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"I Am So Proud of You"
"I Am So Proud of You" (short), 2008. A man with unspecified neurological problems, chapter two.
Written by, directed by & starring Don Hertzfeldt.
Story: 2/4 (Indifferent)
Characters: 3/4 (Good)
Dialog: 4/4 (Great)
Pacing: 4/4 (Great)
Cinematography: 4/4 (Great)
Special effects/design: 4/4 (Great)
Acting: 4/4 (Great). It would have been nice to have an actor do the narration, but he does better on this one than the other two chapters.
Music: 4/4 (Great)
Subjective Rating: 10/10 (Favorite of my favorites, 4/4). The comedy of the Beautiful Day trilogy, and Hertzfeldt's masterpiece. I can't think of anything else that combines hilarity and beauty like this, keeping both of them going at the same time. The sequence in which we learn Bill's family history is probably the best thing from any film I've ever seen.
Objective Rating (Average): 3.6/4 3.7/4 (Great)
(update of a previous post - original is here)
Posted by Daniel at 12:39 PM No comments:
Best of My 2012
The best titles in each of my ratings categories, of everything I saw for the first time since last year's year-end list:
1. The Wiz, 1978
2. The War of the Worlds, 1953
3. Fantastic Planet, 1973
1. 4 Months, 3 Weeks and 2 Days, 2007
2. Looper, 2012
3. A Separation, 2011
1. Beginners, 2011
2. Moonrise Kingdom, 2012
3. Breaking Bad (tv series), 2008
1. The Guard, 2011
2. Animal Crackers, 1930
1. Swing Time, 1936
2. The Avengers, 2012
3. The Lady Eve, 1941
1. Planet Earth (tv series), 2006
2. Skyfall, 2012
3. Days of Heaven, 1978
Special Effects/Design
1. Prometheus, 2012
2. Brave, 2012
3. Band of Brothers (tv series), 2001
1. Shame, 2011
2. A Woman Under the Influence, 1974
3. Tinker Tailor Soldier Spy, 2011
1. Hedwig and the Angry Inch, 2001
2. Dr. No, 1962
3. Midnight in Paris, 2011
Subjective Rating
1. Moonrise Kingdom, 2012 (9/10)
2. The Avengers, 2012 (9/10)
3. Doctor Who (tv series), 2011-2012 (9/10)
4. Swing Time, 1936 (8/10)
5. Game of Thrones (tv series), 2011 (8/10)
Objective Rating
1. Moonrise Kingdom, 2012 (3.7/4)
2. Looper, 2012 (3.5/4)
3. Warrior, 2011 (3.4/4)
4. The Guard, 2011 (3.4/4)
5. Skyfall, 2012 (3.4/4)
Labels: lists
"It's Such a Beautiful Day"
"It's Such a Beautiful Day" (short), 2011. A man with unspecified neurological problems, chapter three.
Concept: 2/4 (Indifferent)
Pacing: 2/4 (Indifferent). It's the first Don Hertzfeldt film where I found myself checking the time.
Acting: 2/4 (Indifferent). The voice work continues to be mediocre, but this time the animation doesn't make up for it - the character is too out of it to warrant any acting.
Music: 3/4 (Good)
Subjective Rating: 8/10 (Great, 4/4). There's hardly any humor. There's none of the amazing expressiveness to the animation that I loved so much in the previous installment. Mostly the focus is on special effects and novel visuals. It's a beautiful, and beautifully sad, film, but it's more pretentious than fun.
Objective Rating (Average): 2.9/4 (Good)
The Dick Van Dyke Show: Season One
The Dick Van Dyke Show: Season One, 1961-1962. A goofy husband/father writes for a TV show.
Created by Carl Reiner. Directed by John Rich (23 episodes), Sheldon Leonard (3), Robert Butler (2) & James Komack (2). Written by Reiner (19 episodes), David Adler (3), Walter Kempley (2), Norm Liebmann (2), Ed Haas (2), Jack Raymond (1), Arnold Peyser (1), Lois Peyser (1), Leo Solomon (1), Ben Gershman (1) & John Whedon (1). Starring Dick Van Dyke.
Story: 1/4 (Bad)
Dialog: 3/4 (Good)
Pacing: 3/4 (Good)
Special effects/design: 2/4 (Indifferent)
Acting: 2/4 (Indifferent). Great performances; okay acting.
Subjective Rating: 7/10 (Good, 3/4). Hilarious, but too sitcom-y. I guess that's unavoidable with an early 60's sitcom. I just wish this cast was in a variety show instead. The best parts are when they stop the plot for a few minutes and just put on an act of some sort.
Labels: dick van dyke show
"Orange Blossoms for Violet"
"Orange Blossoms for Violet" (short), 1952. A monkey melodrama.
Unknown director. Written by Friz Freleng & Chuck Jones. Starring Mel Blanc.
Concept: 1/4 (Bad)
Story: 0/4 (Terrible)
Characters: 0/4 (Terrible)
Dialog: 1/4 (Bad)
Pacing: 2/4 (Indifferent)
Acting: 1/4 (Bad). Mel Blanc couldn't even be troubled to give the different characters unique voices.
Subjective Rating: 2/10 (Terrible, 0/4). The Looney Tunes staff tortures animals for a laugh. They don't even have them do or say anything funny; just their being on screen is supposed to be enough, I guess.
Objective Rating (Average): 1.1/4 (Bad)
Posted by Daniel at 1:45 PM No comments:
Doctor Who #107: Nightmare of Eden
Doctor Who: "Nightmare of Eden," 1979 (the fourth story of six from season seventeen). A passenger spaceship carrying a drug smuggler materializes on top of another ship.
Created by Sydney Newman, C.E. Webber & Donald Wilson. Directed by Alan Bromly & Graham Williams. Written by Bob Baker. Starring Tom Baker & Lalla Ward.
Cinematography: 1/4 (Bad)
Special effects/design: 1/4 (Bad). Mediocre design, terrible effects.
Music: 1/4 (Bad)
Subjective Rating: 5/10 (Indifferent, 2/4). Occasional great dialog and some clever ideas keep it watchable. The script is a mess, but it's a silly mess that might have made for a fun serial. It's execution, though, is bad at best.
Objective Rating (Average): 1.8/4 (Eh)
Labels: doctor who 1963
Game of Thrones: Season One
From my Best TV Shows We've Never Seen marathon - part 4 of 5.
Game of Thrones: Season One, 2011. Various factions plot to gain political control over a fantasy world.
Created by David Benioff & D. B. Weiss, based on books by George R. R. Martin. Directed by Brian Kirk (3 episodes), Daniel Minahan (3), Tim Van Patten (2) & Alan Taylor (2). Written by Benioff (8 episodes), Weiss (8), Bryan Cogman (1), Jane Espenson (1) & Martin (1). Starring Sean Bean.
Story: 3/4 (Good)
Characters: 4/4 (Great)
Pacing: 3/4 (Good). It could have been an hour or two shorter without losing anything. That didn't bother me while I was watching it (except when that damn raven dream kept repeating), but I expect it would seriously mar the show's rewatchability.
Special effects/design: 3/4 (Good). Crazy good for a TV show.
Acting: 3/4 (Good)
Subjective Rating: 8/10 (Great, 4/4). I'm reluctantly giving it an 8 instead of a 9. I loved watching it, but there are a few major problems. Some key plot points are unexplained. Martin's obsession with incest is off-putting. Some of the villains are senselessly evil just for the sake of being villains (huge pet peeve of mine). Oddly, the biggest problem is that there is a ridiculous amount of gratuitous sex and nudity, to the point where it becomes funny. The general rule seems to be that if there's no good reason for characters to not be having sex during their scene, then what are their clothes still on for goddamnit? HBO viewers demand titties! Fantasy is always treading a fine line between immersing and silly, so a show like this that takes itself Very Seriously couldn't do much worse than give you a reason to laugh at it.
Labels: best tv shows marathon, game of thrones
"Haunted Spooks"
"Haunted Spooks" (short), 1920. A girl must marry someone and live in a house in order to inherit it.
Directed by Alfred J. Goulding & Hal Roach. Written by H.M. Walker. Starring Harold Lloyd & Mildred Davis.
Characters: 1/4 (Bad)
Special effects/design: 3/4 (Good)
Acting: 3/4 (Good). Mildred Davis is adorable in this. At one point she almost steals a scene just by laughing at Harold.
Subjective Rating: 6/10 (Okay, 2/4). Most of the film is good. Some of Lloyd's funniest bits are in it, and it doesn't have any down time. But once they finally get around to the haunted spooks part (which is just at the end), it turns racist; they put the gags on hold for some minstrel crap.
"Beep, Beep"
"Beep, Beep" (short), 1952. Coyote tries to catch Roadrunner.
Directed by Chuck Jones. Written by Michael Maltese.
Subjective Rating: 8/10 (Great, 4/4). Roadrunner cartoons might be recycled, repetitive, and effectively made on an assembly line, but that doesn't matter much because in the end they work. Jones and Maltese know how to pull off gags brilliantly, and this format lets them just do that with nothing else to get in the way.
The Sound of Music, 1965. A governess brings music and joy back into a motherless home; also, Nazis.
Directed by Robert Wise. Written by Ernest Lehman, based on a play by Howard Lindsay & Russel Crouse. Starring Julie Andrews.
Cinematography: 3/4 (Good)
Music: 3/4 (Good). The songs are great, but they aren't great film music. They rarely do anything to advance the story, there's too many of them, and they go on for too long (often with nothing happening on screen while they're sung).
Subjective Rating: 6/10 (Okay, 2/4). It has it's moments - nowhere near enough of them to warrant a three-hour movie, but they're in there.
Downton Abbey: Series One
Downton Abbey: Series One, 2010. The goings-on in a large English household in the 1910s.
Created by Julian Fellowes. Directed by Brian Percival (3 episodes), Ben Bolt (2) & Brian Kelly (2). Written by Fellowes, with Shelagh Stephenson (1 episode) & Tina Pepler (1). Starring Hugh Bonneville, Brendan Coyle, Michelle Dockery, Rob James-Collier & Dan Stevens.
Story: 2/4 (Indifferent). Spiteful people backstabbing each other is not my idea of entertaining drama.
Characters: 2/4 (Indifferent). And occasionally finding out secrets about characters is not my idea of development.
Subjective Rating: 6/10 (Okay, 2/4). It's well done for what it is. I just don't see the appeal of this sort of thing. It probably doesn't help that it portrays an oppressive world as something good and noble. At one point the family patriarch makes a little speech about being merely a custodian of his estate, implying that he's burdened with responsibility and not, contrary to all evidence, obscenely privileged. And of course he's fair and protective of his underlings, and they're all much happier in servitude than they would be otherwise. It's pretty disgusting. But then, I'm a straight male, so no one expects me to enjoy this kind of show. My wife liked it.
Labels: downton abbey
"Gift Wrapped"
"Gift Wrapped" (short), 1952. Sylvester vs. Tweety on Christmas morning.
Directed by Friz Freleng. Written by Warren Foster. Starring Mel Blanc.
Subjective Rating: 5/10 (Indifferent, 2/4). More typical Sylvester and Tweety. Not too bad. Doesn't do anything to justify its existence (except for that one shot of Sylvester above, which perfectly captures my feelings toward Tweety Bird).
Objective Rating (Average): 2.0/4 (Indifferent)
4 Months, 3 Weeks and 2 Days
4 luni, 3 saptamâni si 2 zile, 2007. A girl helps her friend get an illegal abortion in Communist Romania.
Written & directed by Cristian Mungiu. Starring Anamaria Marinca.
Concept: 0/4 (Terrible). It has an amazing score of 97 on metacritic.com, so into the Netflix queue it went. If I had bothered to read a synopsis, then the fact that it's supposed to be one of the best movies ever made would probably have been insufficient enticement to watch it. If only I had.
Story: 4/4 (Great)
Pacing: 2/4 (Indifferent). Deliberately very slow. If it had been a movie that wasn't 100% misery, it might have been great, interesting pacing. As it is, it's excruciating.
Cinematography: 3/4 (Good). Shakey cam, but used appropriately.
Music: 2/4 (Indifferent). No music, with a lot of uncomfortable silences. It would have been a very different movie if it had music, probably less harrowing, and I would be A-Okay with that. And then there's the closing credits, with a terrible pop song.
Subjective Rating: 2/10 (Terrible, 0/4). Next time I'm tempted to call a film "joyless," I will have to think twice; my perspective on how relentlessly miserable a film can be has been changed. It's the kind of movie that's perfectly executed, couldn't be more effective, and I wish it wasn't - because what Mungiu is evoking is, to say the least, not something I want to experience. I literally had to scream after watching it. I'm still recovering.
"Tweet Tweet Tweety"
"Tweet Tweet Tweety" (short), 1951. Sylvester vs. Tweety in a national park.
Special effects/design: 4/4 (Great). Wonderful backgrounds.
Music: 4/4 (Great). Stalling's score is great enough to compensate for Tweety's singing.
Subjective Rating: 4/10 (Eh, 2/4). I just... I just do not understand why they kept making Tweety cartoons. The more I watch, the more I hate them.
It's a Very Merry Muppet Christmas Movie
It's a Very Merry Muppet Christmas Movie (tv special), 2002. The Muppets are broke, and Kermit wishes he'd never been born.
Directed by Kirk R. Thatcher. Written by Tom Martin & Jim Lewis. Starring Steve Whitmire, Dave Goelz, Bill Barretta & Eric Jacobson.
Subjective Rating: 7/10 (Good, 3/4). Inconsistent. Sometimes it's great, sometimes it's cringe-inducingly bad. The World In Which Kermit Was Never Born sequence is great enough to keep me liking the movie and think of it as part of the Muppets Tonight/Muppets from Space era, rather than the disastrous Disney TV Movie era.
Destiny, 1921. A woman challenges Death for the life of her fiancé.
Directed by Fritz Lang. Written by Lang & Thea von Harbou. Starring Lil Dagover, Walter Janssen & Bernhard Goetzke.
Concept: 4/4 (Great)
Subjective Rating: 4/10 (Eh, 2/4). It's divided into five segments, each with a distinct tone. The first three are pretty good - first a folktale-ish horror story, followed by a couple adventure-packed melodramas. Then it goes suddenly and horrendously racist. After that, returning to the original story for its conclusion, I'd completely lost interest in the movie. Sadly, one part bad movie plus four parts good movie adds up to one bad movie.
The Wire: Season One
The Wire: Season One, 2002. A backward police department tries to catch a drug kingpin.
Created by David Simon. Directed by Clark Johnson (3 episodes), Clement Virgo (2), Peter Medak (1), Ed Bianchi (1), Joe Chappelle (1), Gloria Muzio (1), Milčo Mančevski (1), Brad Anderson (1), Steve Shill (1) & Tim Van Patten (1). Written by David Simon (8 episodes), Ed Burns (2), Rafael Alvarez (1), David H. Melnick (1), Shamit Choksey (1), Joy Lusco (1) & George Pelecanos (1); story by Simon & Burns. Starring Dominic West.
Characters: 4/4 (Great). There are about a dozen main characters, and every one of them has a distinct voice and a well-developed arc. I don't sympathize with any of them (and don't even particularly enjoy watching most of them), but they are interesting and seem completely real.
Subjective Rating: 7/10 (Good, 3/4). Solidly written and engaging. Normally I couldn't care less about drug dealers or corrupt cops, but this show's got me curious to see what happens next.
Labels: best tv shows marathon, wire
"A Bear for Punishment"
"A Bear for Punishment" (short), 1951. The three bears celebrate Father's Day.
Directed by Chuck Jones. Written by Michael Maltese. Starring Bea Benaderet, Billy Bletcher & Stan Freberg.
Subjective Rating: 5/10 (Indifferent, 2/4). Most of the gags don't make me laugh. It has its moments, though; Ma Bear is amusing, and there's some great animation here and there.
"From Hand to Mouth"
"From Hand to Mouth" (short), 1919. A tramp saves an heiress.
Directed by Alfred J. Goulding & Hal Roach. Written by Harold Lloyd & H.M. Walker. Starring Harold Lloyd & Mildred Davis.
Subjective Rating: 6/10 (Okay, 2/4). It steps into Charlie Chaplin territory more than a little, and of course Lloyd is no Chaplin. It's pretty funny, though.
"Cheese Chasers"
"Cheese Chasers" (short), 1951. Suicidal mice try to get a cat to eat them.
Directed by Chuck Jones. Written by Michael Maltese. Starring Mel Blanc.
Subjective Rating: 7/10 (Good, 3/4). Twisted, and very funny. It has no ending, though. And the quality of the animation is inconsistent.
Hedwig and the Angry Inch, 2001. An unsuccessful glam rocker tells and sings her life story.
Written by, directed by & starring John Cameron Mitchell, based on a play by Mitchell & Stephen Trask.
Subjective Rating: 8/10 (Great, 4/4). The story of Unfair Show Business and Generally Having a Crappy Life isn't interesting (especially since Hedwig is too much of a diva to get any sympathy), but that's not too important. It's sufficient story to hang the music on, and the music is what matters. If a typical musical is a story with songs injected, this is the other way around - kind of like an elaborate concert film, with story injected to keep it rolling.
Goldfinger, 1964. A gold smuggler plans to break into Fort Knox.
Directed by Guy Hamilton. Written by Richard Maibaum & Paul Dehn, based on a book by Ian Fleming. Starring Sean Connery & Gert Fröbe.
Subjective Rating: 7/10 (Good, 3/4). All the nonsense and plot holes of Dr. No, but without nearly as much fun. And James Bond does nothing whatsoever to stop the evil plot. Still pretty good, though. Almost everything in it is iconic.
Doctor Who: Series Seven, Part One
Doctor Who: Series Seven Part One, 2012. An alien travels through space and time with a human couple.
Created by Sydney Newman, C.E. Webber & Donald Wilson. Directed by Nick Hurran (2 episodes), Saul Metzstein (2) & Douglas Mackinnon (1). Written by Steven Moffat (2 episodes), Chris Chibnall (2) & Toby Whithouse (1). Starring Matt Smith, Karen Gillan & Arthur Darvill.
Story: 2/4 (Indifferent). The plots are either predictable, or Swiss cheese. It's a huge improvement over season six, but Moffat's still more interested in writing Clever Twists than telling stories.
Dialog: 3/4 (Good). Not as many great joke lines as I expect from Moffat's Doctor, and some occasional awfulness.
Pacing: 2/4 (Indifferent). Too fast. Mostly good, but the Ponds' exit is frustratingly incomplete.
Special effects/design: 3/4 (Good). Often great, sometimes terrible.
Subjective Rating: 9/10 (One of my favorites, 4/4 5/4). I don't find any of the individual episodes to be particularly remarkable (at least not compared to what the show was doing a few years ago); the best ones fall apart at the end when the plot holes are brushed aside with babble. But the tone of the show is back to the old standard of fun and adventure, and I'm back to being Unreasonably Excited about watching it.
Objective Rating (Average): 2.9/4 3.0/4 (Good)
El secreto de sus ojos, 2009. A retired court employee writes a book about a 25-year-old case.
Directed by Juan José Campanella. Written by Eduardo Sacheri & Campanella, based on Sacheri's book. Starring Ricardo Darín & Soledad Villamil.
Pacing: 1/4 (Bad)
Special effects/design: 1/4 (Bad). Appallingly bad aging makeup. He actually looks older in the flashbacks.
Subjective Rating: 4/10 (Eh, 2/4). It could have been worse; there are a couple scenes that work very well. If it had just been a crime/mystery story, it might have been good, but it's all framed within a terribly-written love story. Why are we expected to care (especially with all the other stuff going on in this movie) about a couple of boring characters' inability to express their feelings?
Breaking Bad: Season One
Breaking Bad: Season One, 2008. A terminally ill science teacher takes up cooking meth.
Created by Vince Gilligan. Directed by Adam Bernstein (2 episodes), Gilligan (1), Jim McKay (1), Tricia Brock (1), Bronwen Hughes (1) & Tim Hunter (1). Written by Gilligan (4 episodes), Patty Lin (1), George Mastras (1) & Peter Gould (1). Starring Bryan Cranston.
Subjective Rating: 8/10 (Great, 4/4). Well that was fun. People might be on to something with this whole Watching TV thing that's so popular lately.
Objective Rating (Average): 3.3/4 (Very good)
Labels: best tv shows marathon, breaking bad
Doctor Who: "The Doctor, the Widow and the Wardrobe"
Doctor Who: "The Doctor, the Widow and the Wardrobe" (tv special), 2011. A British family during WWII is treated to an unusual Christmas holiday.
Created by Sydney Newman, C.E. Webber & Donald Wilson. Directed by Farren Blackburn. Written by Steven Moffat. Starring Matt Smith & Claire Skinner.
Concept: 4/4 (Great). Domestic Doctor is always welcome.
Subjective Rating: 9/10 (One of my favorites, 4/4 5/4). Now that I've finally gotten around to watching this, I'm very relieved to find Doctor Who turning in the complete opposite direction of the cluttered, fast-forward mess of series six. There are still a lot of problems with the story, but nothing too bad. The focus is back on characters, and taking the time to let the audience care about what's happening to them. As far as emotional impact goes, this is the strongest episode so far of the Smith/Moffat era - maybe of the entire series.
Objective Rating (Average): 3.1/4 3.2/4 (Very good)
"French Rarebit"
"French Rarebit" (short), 1951. Bugs Bunny vs. French chefs.
Directed by Robert McKimson. Written by Tedd Pierce. Starring Mel Blanc.
Subjective Rating: 4/10 (Eh, 2/4). Old gags that weren't that great to begin with, executed poorly. Apart from a nice performance by Mel Blanc, it's got nothing going for it.
Skyfall, 2012. James Bond vs. a computer hacker from M's past.
Directed by Sam Mendes. Written by Neal Purvis, Robert Wade & John Logan, based on characters by Ian Fleming. Starring Daniel Craig, Judi Dench & Javier Bardem.
Concept: 2/4 (Indifferent). Oh no, he's in the computers! Quick, Hipster Q, type faster than him! Okay, that's only about ten minutes of the movie, but still, it is the basic premise behind the plot. Your audiences are no longer computer illiterate, Hollywood; that shit is just ridiculous.
Story: 3/4 (Good). Very good, but there's too much of it for one movie.
Cinematography: 4/4 (Great). Holy bejesus this movie is pretty - even by Roger Deakins standards.
Acting: 4/4 (Great)
Music: 3/4 (Good). Sometimes great, sometimes generic Action Movie Noises.
Subjective Rating: 8/10 (Great, 4/4). Granted, I've only seen five of them in recent memory, but this is easily the best James Bond movie I've seen. Lots of fun, and expertly crafted. Serious Director + Action Movie = Everybody Wins.
"Bumping into Broadway"
"Bumping into Broadway" (short), 1919. A boy and girl trying to make it into show business have no money.
Directed by Hal Roach. Written by H.M. Walker. Starring Harold Lloyd & Bebe Daniels.
Subjective Rating: 6/10 (Okay, 2/4). Slow at first, but eventually gets around to zany, madcap antics.
Chicken Run, 2000. Chickens try to escape from a farm.
Directed by Peter Lord & Nick Park. Written by Karey Kirkpatrick, with Mark Burton & John O'Farrell; story by Lord & Park. Starring Julia Sawalha & Mel Gibson.
Dialog: 2/4 (Indifferent). Mostly bad, with moments of greatness.
Subjective Rating: 6/10 (Okay, 2/4). The story and character arcs could not be more generic, and most of the jokes aren't funny. It still manages to be an entertaining movie, though; there's enough Aardman charm to make up for the script.
Star Trek: The Next Generation: Season Seven
Star Trek: The Next Generation: Season Seven, 1993-1994. A giant space ship flies around the galaxy, ostensibly exploring but usually running errands.
Created by Gene Roddenberry. Directed by Alexander Singer (3 episodes), Cliff Bole (3), Robert Wiemer (3), Winrich Kolbe (3), Patrick Stewart (2), Les Landau (2), Jonathan Frakes (2), Peter Lauritson (1), Robert Lederman (1), Robert Scheerer (1), LeVar Burton (1), Gabrielle Beaumont (1), Gates McFadden (1), Corey Allen (1) & Jonathan West (1). Written by Brannon Braga (8 episodes), René Echevarria (6), Ronald D. Moore (6), Naren Shankar (5), Joe Menosky (3), Christopher Hatton (2), Nicholas Sagan (2), Jeanne Carrigan-Fauci (1), Lisa Rich (1), Roger Eschbacher (1), Jaq Greenspon (1), Hilary J. Bader (1), Dan Koeppel (1), Spike Steingasser (1), William N. Stape (1), Jeri Taylor (1), Jeanna F. Gallo (1), Ron Wilkerson (1), Jean Louise Matthias (1), Shawn Piller (1), Antonia Napoli (1) & Mark Kalbfeld (1). Starring Patrick Stewart & Jonathan Frakes.
Subjective Rating: 6/10 (Okay, 2/4). It's more concerned with wrapping up old unresolved storylines (that had been left unresolved because no one gave a crap about them) than with doing anything interesting. By my count, there are only two great episodes, about six other good episodes, three or four bad episodes, and a couple of terrible episodes (including the clear Worst TNG Episode Ever). That leaves about half a season of mediocrity - a pretty sad way for the show to go out.
Labels: star trek tng
Band of Brothers (tv series), 2001. A company of WWII paratroopers fights through Europe.
Directed by Mikael Salomon (2 episodes), David Frankel (2), Phil Alden Robinson (1), Richard Loncraine (1), David Nutter (1), Tom Hanks (1), David Leland (1) & Tony To (1). Written by Erik Jendresen (3 episodes), Bruce C. McKenna (3), John Orloff (2), Graham Yost (2), Erik Bork (2), Tom Hanks (1) & E. Max Frye (1); based on a book by Stephen E. Ambrose. Starring Damian Lewis (4 episodes), David Schwimmer (1), Marc Warren (1), Michael Cudlitz (1), Shane Taylor (1), Donnie Wahlberg (1), Eion Bailey (1), Colin Hanks (1) & Ron Livingston (1).
Characters: 2/4 (Indifferent). I had a hard time keeping the supporting characters straight. There's a lot of story and action; with only ten episodes, there's not enough time left to clearly establish an army of characters.
Music: 3/4 (Good). Mostly mediocre, with moments of greatness.
Subjective Rating: 5/10 (Indifferent, 2/4). Very engrossing, but draining. I never looked forward to the next episode.
Labels: best tv shows marathon
"Room and Bird"
"Room and Bird" (short), 1951. Sylvester and Tweety in a hotel.
Directed by Friz Freleng. Written by Tedd Pierce & Warren Foster. Starring Mel Blanc.
Music: 2/4 (Indifferent). Why must Tweety sing?
Subjective Rating: 5/10 (Indifferent, 2/4). I hate 1950s Tweety so much. It's like they think it's funny to make him as obnoxious as possible.
Animal Crackers, 1930. Some Marx Brothers characters show up at a socialite party.
Directed by Victor Heerman. Written by Morrie Ryskind, with Pierre Collings, based on a play by George S. Kaufman, Ryskind, Bert Kalmar & Harry Ruby. Starring The Marx Brothers.
Acting: 1/4 (Bad)
Music: 3/4 (Good). It opens with a barrage of terrible numbers, but later musical interludes are the best things in the movie.
Subjective Rating: 6/10 (Okay, 2/4). It has a traditional farce plot, which is at odds with the Marx Brothers' style - when silliness breaks out, it's jarring and confusing as often as funny (usually both), and when it returns to the story it's a tedious distraction. The jokes are great, and a lot of the routines are hilarious, but overall it's a badly-made movie.
"Bangville Police"
"Bangville Police" (short), 1913. Police respond to a farm girl's call.
Directed by Henry Lehrman. Starring Fred Mace & Mabel Normand.
Dialog: 1/4 (Bad). Not enough of it, and never any jokes.
Subjective Rating: 3/10 (Bad, 1/4). I guess this is supposed to be a comedy? It's just a lot of exaggerated gestures and expressions, like someone might make who's trying to entertain a baby.
Moonrise Kingdom, 2012. Two kids run away together.
Directed by Wes Anderson. Written by Anderson & Roman Coppola. Starring Jared Gilman & Kara Hayward.
Pacing: 4/4 (Great). Great as far as the story on hand is concerned. However, there are a lot of great supporting characters who don't get nearly enough screen time to do them justice. There could be entire movies about most of them.
Subjective Rating: 9/10 (One of my favorites, 4/4 5/4). Anderson's best movie. It's kind of like the ideas from his earlier stuff is filtered through Fantastic Mr. Fox's cartoony-ness, ending up with the best of both worlds.
"Bunny Hugged"
"Bunny Hugged" (short), 1951. Bugs Bunny in a wrestling match.
Subjective Rating: 6/10 (Okay, 2/4). There are some good laughs in there, but a lot of the gags didn't do anything for me.
From Russia with Love, 1963. SPECTRE sets a trap for James Bond.
Directed by Terence Young. Written by Richard Maibaum; adapted by Johanna Harwood from a book by Ian Fleming. Starring Sean Connery.
Subjective Rating: 6/10 (Okay, 2/4). It's not fun enough. The action scenes are bad and go on too long. It doesn't have the great sense of style that Dr. No has. On the other hand, it also doesn't have any of the story problems that Dr. No has.
Meet the Robinsons
Meet the Robinsons, 2007. An orphan is taken to the future by a boy with his parents' time machine.
Directed by Stephen J. Anderson. Written by Jon Bernstein, Michelle Bochner, Don Hall, Nathan Greno, Aurian Redson, Joseph Mateo & Stephen J. Anderson, based on a book by William Joyce. Starring Daniel Hansen, Jordan Fry, Wesley Singerman & Stephen J. Anderson.
Story: 1/4 (Bad). A cookie-cutter story arc, and long stretches of stuff that has nothing to do with anything.
Pacing: 2/4 (Indifferent). A frantic mess, but often in a good way.
Special effects/design: 3/4 (Good). Great design. Some pretty bad animation.
Acting: 3/4 (Good). The child leads are mediocre at best, but there are some great comedic performances.
Subjective Rating: 7/10 (Good, 3/4). Manic beyond all reason, and hilarious. One of those surprise movies that has no business being as good as it is.
"The Girl and Her Trust"
"The Girl and Her Trust" (short), 1912. A telegraph operator is alone at a train station when it is robbed.
Directed by D.W. Griffith. Written by George Hennessy. Starring Dorothy Bernard & Wilfred Lucas.
Characters: 3/4 (Good). A female action hero in 1912. Neat.
Acting: 3/4 (Good). There's the occasional Theater Pose, but mostly it's very good.
Subjective Rating: 6/10 (Okay, 2/4). Surprisingly entertaining. I wouldn't quite go so far as to call it exciting, but it does pretty well.
Nanook of the North
Nanook of the North, 1922. A look at the difficult life of an Inuit family.
Written & directed by Robert J. Flaherty. Starring Allakariallak.
Cinematography: 3/4 (Good). Surprisingly modern.
Special effects/design: n/a
Acting: n/a
Subjective Rating: 5/10 (Indifferent, 2/4). It's kind of like looking at a series of museum dioramas, except that they move. And Nanook is a ham.
Mulan, 1998. A woman joins the army in drag to save her elderly father.
Directed by Tony Bancroft & Barry Cook. Written by Rita Hsiao, Chris Sanders, Philip LaZebnik, Raymond Singer, Eugenia Bostwick-Singer, Dean DeBlois, Robert D. San Souci & 24 others. Starring Ming-Na Wen.
Music: 0/4 (Terrible)
Subjective Rating: 5/10 (Indifferent, 2/4). Crap. It moves fast enough and has enough action to keep it from being too painful to watch.
VSM: The Best TV Shows We've Never Seen
These are the titles with the highest IMDb score and at least 25,000 votes (and that are available in the US) that we haven't seen. And they all happen to be TV shows, which suits us as we've been itching to watch more TV lately.
Very Slow Marathon #12 - The Best TV Shows We've Never Seen
-Band of Brothers (2001)
-Breaking Bad (season 1, 2008)
-The Wire (season 1, 2002)
-Game of Thrones (season 1, 2011)
-The Sopranos (season 1, 1999)
Brave, 2012. A teenage princess has her mother turned into a bear.
Directed by Mark Andrews, Brenda Chapman & Steve Purcell. Written by Andrews, Purcell, Chapman & Irene Mecchi; story by Chapman. Starring Kelly Macdonald.
Subjective Rating: 8/10 (Great, 4/4). Very underrated. No, it's not the best Pixar movie (that's hardly a fair comparison to make for any movie), but it might be the strongest emotionally. My wife observes that it's the first time a fight scene made her cry.
"La Luna"
"La Luna" (short), 2012. A boy learns the family trade, on the moon.
Written & directed by Enrico Casarosa. Starring Krista Sheffler, Tony Fucile & Phil Sheridan.
Subjective Rating: 7/10 (Good, 3/4). Cute, with some nice whimsy. But apart from the basic idea, there's nothing to the story. And its tendency for swelling music and slow motion make it feel like it has a high opinion of itself.
Rebel without a Cause
Rebel without a Cause, 1955. Angsty teenagers get into trouble.
Directed by Nicholas Ray. Written by Stewart Stern; adapted by Irving Shulman; story by Ray. Starring James Dean, Natalie Wood & Sal Mineo.
Subjective Rating: 7/10 (Good, 3/4). The first half is great. After the "chickie run," it's still good, but the tension drops out. I can't quite say why, but I just don't feel it anymore; there's a lot of waiting around for inevitable tragedy.
The Storyteller (tv series), 1988. An old man tells folktales to his dog.
Created by Jim Henson. Directed by Steve Barron (3 episodes), Jim Henson (2), Charles Sturridge (1), Jon Amiel (1), Peter Smith (1) & Paul Weiland (1). Written by Anthony Minghella. Starring John Hurt.
Subjective Rating: 8/10 (Great, 4/4). At its best it's fun, and at its worst it's at least interesting. It's one of the only faithful screen adaptation of fairy tales. They just don't make shows like this - and understandably. Henson and Minghella apparently just said "fuck it" to every conventional idea of what audiences like and made the weird-ass show they felt like making.
Star Trek: Deep Space Nine: Season One
Star Trek: Deep Space Nine: Season One, 1993. Democratic imperialists and former terrorists work together on a space station in order to keep away fascist imperialists.
Created by Rick Berman & Michael Piller. Directed by Paul Lynch (5 episodes), David Carson (4), David Livingston (3), Winrich Kolbe (2), Les Landau (2), Corey Allen (1), Robert Legato (1), Cliff Bole (1) & James L. Conway (1). Written by Michael Piller (8 episodes), Ira Steven Behr (3), Robert Hewitt Wolfe (3), Peter Allan Fields (3), Rick Berman (2), Lisa Rich (2), Jeanne Carrigan-Fauci (2), Katharyn Powers (1), Gerald Sanford (1), Michael McGreevey (1), Naren Shankar (1), Sally Caves (1), Jill Sherman Donner (1), Hannah Louise Shearer (1), D.C. Fontana (1), Morgan Gendel (1), Frederick Rappaport (1), David Livingston (1), Sam Rolfe (1), Richard Danus (1), Evan Carlos Somers (1), Hilary J. Bader (1), Kurt Michael Bensmiller (1), Nell McCue Crawford (1), William L. Crawford (1), Don Carlos Dunaway (1), Jim Trombetta (1) & Joe Menosky (1). Starring Avery Brooks.
Concept: 1/4 (Bad). It takes the entire two-hour pilot just to explain the set-up, which is crap, but it doesn't matter much anyway since it's irrelevant for most of the show.
Characters: 1/4 (Bad). O'Brien is the only main character who isn't a jackass.
Special effects/design: 1/4 (Bad). It's good, in-so-far as everything looks exactly like it should look. It's not the artists' fault that the writers asked for a world that's dull and vaguely unpleasant to look at.
Acting: 1/4 (Bad). Some truly awful acting. (Although, again, O'Brien is the exception to the rule.)
Subjective Rating: 5/10 (Indifferent, 2/4). At its best, it's just barely an okay show. Usually, it's crap. The stories are the biggest offender - poorly conceived, uninteresting, and filled with plot holes and continuity problems. The show has a pretty good reputation, though, so I'd like to hope that that area will be fixed in later seasons. But short of a complete retooling, it could never be as good as TNG, simply because none of these characters get along. DS9's whole concept is that it's about unpleasant people, forced to work together on a job they don't want to do, in a place they don't want to be. What's fun about watching that?
Labels: star trek ds9
The Little Mermaid, 1989. A mermaid falls in love with a human and makes a deal with a witch.
Written & directed by Ron Clements & John Musker, based on the fairy tale by Hans Christian Andersen. Starring Jodi Benson, Christopher Daniel Barnes, Pat Carroll & Samuel E. Wright.
Pacing: 2/4 (Indifferent). Slow to get started, then over too fast once it gets good.
Music: 2/4 (Indifferent). Some pretty bad songs, but they're usually an effective and integral part of the storytelling.
Subjective Rating: 7/10 (Good, 3/4). There's a strong sense of fun and charm that's sadly rare in Disney films from this era. It's also genuinely scary and intense in places.
Before the Devil Knows You're Dead
From my Sidney Lumet marathon, part 8 of 8.
Before the Devil Knows You're Dead, 2007. Two brothers rob their parents' jewelry store.
Directed by Sidney Lumet. Written by Kelly Masterson. Starring Philip Seymour Hoffman, Ethan Hawke, Albert Finney & Marisa Tomei.
Story: 3/4 (Good). Nearly great, but two of the main characters have no resolution.
Subjective Rating: 7/10 (Good, 3/4). Too long, but very good. If it had been promoted as a drama (which it is) instead of an action thriller (which it is decidedly not), it would probably have a much better reputation.
Labels: sidney lumet marathon
"Billy Blazes, Esq."
"Billy Blazes, Esq." (short), 1919. A cowboy rescues the girl from the bad guys.
Directed by Hal Roach. Written by Roach & H.M. Walker. Starring Harold Lloyd.
Subjective Rating: 5/10 (Indifferent, 2/4). Lloyd doesn't even show up until halfway through the film. And by the time he's introduced, they've pretty much run out of jokes - apart from two or three mediocre gags, you wouldn't even think it was a comedy.
"Nero, or the Fall of Rome"
"Nero, or the Fall of Rome" (short), 1909. The emperor's love life leads to revolt.
Directed by Luigi Maggi. Written by Decoroso Bonifanti & Arrigo Frusta. Starring Alberto Capozzi.
Story: 1/4 (Bad). Not a bad plot, but its execution could hardly be worse.
Dialog: 1/4 (Bad). Each scene is preceded by captions which are supposed to explain what's going on, but I can't say they do their job.
Pacing: 0/4 (Terrible)
Acting: 0/4 (Terrible)
Subjective Rating: 3/10 (Bad, 1/4). An absolutely awful film. The acting is bad enough to provide some heckling value, though.
"So Much for So Little"
"So Much for So Little" (short), 1949. The Public Health Service makes an argument for the Public Health Service.
Directed by Chuck Jones. Written by Friz Freleng & Jones. Starring Frank Graham.
Concept: 0/4 (Terrible)
Subjective Rating: 8/10 (Great, 4/4). It's got everything one loves about mid-century educational films, crossed with a heavy dose of Chuck Jones. And although it's a propaganda film, I don't imagine it did much for the government. The tone straddles a line between entertainingly educational, and satire.


text:
\section{Introduction}

The density at which a particular molecular transition is excited has always been
an interesting quantity for studies of molecular gas in the interstellar medium.
Two concepts have been developed, the critical density and the effective excitation
density, to quantify the excitation density of a transition.
A traditional approach in studying the critical density has been to consider
the molecular rotational energy levels as a simple two level system.  While
this approach has pedagogical advantages, the interpretation of
concepts, such as critical density, are oversimplified and incorrect.  Molecules
are fundamentally multi-level systems with radiative and collisional processes between
the levels (Figure 1).  It is almost never appropriate to approximate commonly observed
dense gas tracers, such as HCO$^+$ , HCN, NH$_3$, N$_2$H$^+$ , etc., as two level systems.
Therefore, in this tutorial, we eschew the two level approximation and consider
the full multi-level nature of molecular excitation.  It is assumed
that the reader has a basic familiarity with statistical equilibrium, radiative transfer,
and molecular spectroscopy.  For a summary of radiative transfer techniques and
molecular data used in those calculations, see van der Tak (2011) and references therein.
The purpose of this tutorial is to quantify and
systematize the use of critical density and effective excitation density for
dense gas molecular tracers.

We shall use the excitation of two molecules, HCO$^+$\ and NH$_3$, as examples throughout
this tutorial.  Figure 1 shows the energy level structure for both molecules.
HCO$^+$\ is an abundant linear molecule with a simple $^{1}\Sigma$ electronic ground state
meaning that there is zero net electronic spin and zero net electronic angular momentum that
could interact with and split the rotational levels of the molecule.  Electric dipole
selection rules limit transitions to $\Delta J = \pm 1$.
The $1-0$ ground state rotational transition is a millimeter transition at 89 GHz (3.3 mm)
and the frequency of rotational transitions progress linearly into the submillimeter
part of the spectrum.

NH$_3$ is an abundant pyramidal
symmetric top molecule with a simple $^{1}A_1$ electronic ground state also
meaning that there is zero net electronic spin and zero net electronic angular momentum.
The energy levels are designed by $J_K$ where $J$ is the total rotational angular
momentum and $K$ is the projection of the angular momentum
onto the NH$_3$ symmetry axis.  Electric dipole
transition do not allow the projected angular momentum to change ($\Delta K = 0$).
As a results, the energy level structure is usually organized in K-ladders with each
K-ladder designated as either ortho ($K$ = 0, 3, 6, etc.) or para ($K$ = 1, 2, 4, 5, etc.)
due to the spin symmetry required to satisfy Fermi-Dirac statistics
for each rotational energy level.  The plane of three
H atoms can tunnel from positions above and below the N atom resulting in inversion splitting
of each rotational level (with symmetry denoted by $\pm$)
except for levels with $K = 0$ for which half of the inversion levels
are missing due to the Pauli exclusion principle (see Townes \& Schwalow 1975 for
a detailed explanation).  Electric dipole transitions are allowed between the inversion-split levels
with different symmetries and these inversion transitions occur at wavelengths near 1.3 cm
(24 GHz).
Since $J$ and $K$ do not change in a pure inversion transition,
the shorthand notation $(J,K)$ has been adopted.
As with HCO$^+$ , there are rotational transition with $\Delta J = \pm 1$, but since NH$_3$ is a
lighter molecule than HCO$^+$\ ($E_{rot} \propto 1/I$ where I is the moment of inertia of
the molecule measured from a coordinate system at the center-of-mass),
the transitions occur at submillimeter and far-infrared
wavelengths.  Thus, the lowest energy transitions of HCO$^+$\ and NH$_3$ cover a wide range of
wavelengths from the centimeter to the far-infrared.

\begin{figure}
\figurenum{1}
\epsscale{1.0}
\plottwo{f1a.eps}{f1b.eps}
\figcaption{
Left: The energy level structure for HCO$^+$\ showing the lowest $4$ energy levels.
Electric dipole allowed transitions are shown along with the quantum numbers
($J$) to the right of each level and statistical weights in red to the left of each energy level.
Right:  The energy level structure for NH$_3$ showing the lowest $9$ energy levels.
Electric dipole allowed transitions
are shown along with the quantum numbers ($J_K^{\pm}$) to the right of each level
and statistical weights in red to the left of each energy level.  This figure was
adapted from figures in Mangum \& Shirley (2015).}
\end{figure}

\section{Critical Density}

The critical density has traditionally been used as a measure of the density
at which a particular transition is excited and is observed at radio wavelengths. The definition
of the critical density is not consistent throughout the
literature.  Some definitions only consider the two energy levels involved in the transition
(2 level approximation) while other definitions use the multi-level nature of collisions
to sum over all collisions out of the upper energy level or only from the upper
energy level to lower energy levels.  All of the standard definitions assume the molecular
emission is optically thin and ignore radiative trapping which
is very important and cannot be ignored for many commonly observed dense gas tracers
(e.g. HCN $1-0$, HCO$^+$ $1-0$, N$_2$H$^+$ $1-0$, etc.; see \S2.2).  The standard
definitions also usually ignore continuum backgrounds (see \S4).

We start by defining the critical density as the density
for which the net radiative decay rate from $j \rightarrow k$
equals the rate of
collisional depopulation out of the upper level $j$ for a multilevel system.
The net radiative decay rate from $j \rightarrow k$ is the
spontaneous decay rate from $j \rightarrow k$ plus the stimulated emission rate
from $j \rightarrow k$ minus the absorption rate from $k \rightarrow j$.
Mathematically, the ratio of rates is
\begin{equation}
\Re = \frac{n_j A_{jk} + n_j B_{jk} u_{\nu_{jk}} - n_k B_{kj} u_{\nu_{jk}}}
{n_{c} n_j \sum_{i \neq j} \gamma_{ji}} \;\; ,
\end{equation}
where
$n_j$ is the number density (cm$^{-3}$) of molecules in the upper level of the transition,
$n_k$ is the number density (cm$^{-3}$) of molecules in the lower level of the transition,
$n_c$ is the number density (cm$^{-3}$)  of colliding particles (typically H$_2$, H, or e$^-$),
and $\gamma_{ji}$ are the collision rates (cm$^3$ s$^{-1}$) out of level $j$ into
another level $i$.
$n_c$ is equal to $n_{crit}$ when $\Re = 1$.
$A_{jk}$ and $B_{jk}$ are the Einstein $A$ (s$^{-1}$) and $B$
(erg$^{-1}$ cm$^{3}$ s$^{-2}$) coefficients related by
\begin{equation}
\frac{g_k}{g_j} B_{kj} = B_{jk} = \frac{c^3}{8\pi h\nu^3_{jk}} A_{jk} \;\;\; .
\end{equation}
$u_{\nu_{jk}}$ is the energy density (erg cm$^{-3}$ Hz$^{-1}$) of the radiation fields
at the frequency of the transition $\nu_{jk}$.  The energy density is
written in terms of a Planck function and is related to the angle and
polarization averaged photon occupation number, $n_{ph}$, by
\begin{equation}
u_{\nu}(T) = \frac{8\pi h \nu^3}{c^3} \frac{1}{e^{h\nu/kT} - 1} = \frac{8\pi h \nu^3}{c^3} n_{ph}(T,\nu) \;\;\;.
\end{equation}
The total energy density can include contributions from
the cosmic microwave background (CMB), dust continuum emission from
the interstellar radiation field, dust continuum emission local to the molecular cloud,
optically thick molecular emission at the frequency $\nu_{jk}$,
and other continuum and spectral line sources.

\subsection{Optically Thin Approximation}

We define the optically thin critical density without a background by solving for $n_c$
in Equation 1 when $\Re = 1$ and ignoring the stimulated emission and absorption terms:
\begin{equation}
n_{crit}^{thin, no\; bg} = \frac{ A_{jk} }{\sum_{i \neq j}
\gamma_{ji}} =
\frac{ A_{jk}}{\sum_{i < j} \gamma_{ji} + \sum_{i > j}
\frac{g_i}{g_j} \gamma_{ij} e^{-(E_i - E_j)/kT_k} } \;\;\; .
\end{equation}
The sum over collision rates in the denominator of Equation 4
has been split in two terms depending on whether the collision from level $j$ is to an
energy level lower in energy (first sum) or higher in energy (second sum) than level $j$.
Upward collision rates are related to downward collision rates using detailed
balance by
\begin{equation}
\gamma_{ji} = \gamma_{ij} \frac{g_i}{g_j} e^{-(E_i - E_j)/kT_k} \;\; \rm{for} \;\; E_i > E_j
\end{equation}
where $T_k$ is the kinetic temperature of the collisional partner.
Published collision rates (i.e. the Leiden molecular database\footnote{http://home.strw.leidenuniv.nl/$\sim$moldata/ }; Sch{\"o}ier et al. 2005)
quote only downward collision rates.
In the two level approximation, which is widely quoted but rarely appropriate,
the sums reduce to a single term such that
$n_{crit, 2lvl}^{thin,no\; bg} = \frac{A_{jk}}{\gamma_{jk}}$.  As a result,
$n_{crit, 2lvl}^{thin,no\; bg}$ will always be larger (usually by at least a factor of a few)
than $n_{crit}^{thin, no\; bg}$.

\begin{figure}
\figurenum{2}
\epsscale{1.0}
\plotone{f2.eps}
\figcaption{
Top: The excitation temperature is plotted for the NH$_3$ (1,1) inversion
transition (23.7 GHz, 1.3 cm)
and $1_0-0_0$ rotational transition (572.5 GHz, 0.52 mm) for a gas kinetic
temperature of $10$K and a total NH$_3$ reference column density of
$\log N = 14.8$ cm$^{-3}$ (an ortho to para ratio of $2:1$ is assumed).
The blue dashed line and the green dotted line indicate $n_{crit}^{thin, no\; bg}$
for the (1,1) and $1_0-0_0$ transitions respectively.
Bottom: The variation of excitation temperature for the NH$_3$ (1,1) transition
with gas kinetic temperature is plotted for $T_k =$ 10, 20, and 30 K.}
\end{figure}

It is instructive to compare how the optically thin critical density compares to the excitation temperature.
For a particular transition between levels $j \rightarrow k$,
the level population are related to the excitation temperature, $T_{ex}$, between
the two levels by Boltzmann's equation
\begin{equation}
\frac{n_j}{n_k} = \frac{g_j}{g_k} \exp\left( - \frac{E_j - E_k}{kT_{ex}} \right) \;\; \rm{for} \;\; E_j > E_k \;\; .
\end{equation}
The excitation temperature (and therefore the level populations) depend on the
density of colliding partners ($n_c$), the gas
kinetic temperature of colliding partners ($T_k$), and the energy density of radiation
fields that the molecules are exposed to.  The dependence of $T_{ex}$
on the density and gas kinetic temperature for the ground state
transitions of ortho and para NH$_3$ are
shown in Figure 2.  The only background radiation field assumed in this
example is the CMB.  At low densities ($n_c < 10^3$ cm$^{-3}$), the level populations
come into equilibrium with the CMB and $T_{ex}$ approaches $T_{cmb} = 2.725$ K.
As the density increases, collisions become more important in determining
the level populations.  The excitation temperature of $(1,1)$ centimeter wavelength
inversion transition equilibrates to $T_k$ by densities $> 10^{5.5}$ cm$^{-3}$
while the submillimeter $1_0 - 0_0$ rotational transition equilibrates to
$T_k$ at significantly higher densities ($> 10^7$ cm$^{-3}$).  The general shape
of the $T_{ex}$ with $\log n_c$ curves is a sigmoid curve with stimulated
coupling with the background radiation field setting the lower bound at low
densities and collisions with colliding partners at $T_k$ setting the upper bound.
At densities where $T_{ex} < T_k$, the level populations are said to be
sub-thermally populated.  This is the situation for most of the commonly observed
dense gas transitions in the ISM.
When $T_{ex}$ approaches $T_k$, the level populations are said to be thermalized.\footnote{Note that the $T_{ex}$ curve for NH$_3$ (1,1) shows a region of super-thermal
excitation ($T_{ex} > T_k$) at densities immediately before thermalization for
the $T_k = 30$ K curve.
This is due to a bottleneck in radiative transitions, caused by the five orders of
magnitude difference between the spontaneous emission rates for
the inversion transition and the THz rotational transition into the upper
inversion level, resulting in a slight overpopulation of the upper level of
the inversion transition.  This effect is more pronounced for higher $T_k$
because upward collisions to the $J_K = 2_1$ levels are more efficient at high $T_k$
(see Equation 5).}

At optical wavelengths (the high frequency limit), critical density
is interpreted as the density at which an atomic forbidden line is quenched by
collisions meaning that a collisional de-excitation occurs before a photon can be generated from
spontaneous emission.  In the optical, quenching occurs when $T_{ex}$ is thermalized
($T_{ex} \rightarrow T_{k}$).
At radio wavelengths (the low frequency limit)
the critical density
occurs at different positions along the sigmoid $T_{ex}$ curve for different molecular tracers
and different transitions.
In the case of the 1.3 cm (23.7 GHz)
NH$_3$ (1,1) transition, the optically thin critical density
is two orders of magnitude below the thermalization
density (Figure 2).  Early radio astronomy observations of molecules such as OH and NH$_3$
occurred at centimeter wavelengths and since the critical density at these low
frequencies is just above the regime where the $T_{ex}$ starts to rise
above equilibration with the CMB, critical density was used to indicate the density
at which a transition would appear in emission.  As the frequency of the transition
increases, the critical density moves farther up the $T_{ex}$ curve.
For the $0.52$ mm ($572$ GHz) NH$_3$ $1_0 - 0_0$ transition, the critical density is nearly
equal to the density required for thermalization.  Millimeter transitions are an
intermediate case; thus, neither the radio interpretation of critical density being
the density at which an emission line is excited nor the optical interpretation
of critical density being the density at which an emission line is quenched is appropriate.

\subsection{Optically Thick Emission}

In reality, radiative trapping is very important for many molecular transitions observed
in the dense interstellar medium and cannot be ignored.   The energy
density is then modified using the solution to the equation of radiative transfer
to include emission from the molecule at the excitation temperature describing the
level populations for a transition from $j \rightarrow k$ as
\begin{equation}
u_{\nu_{jk}} = u_{\nu_{jk}}(T_{bg})\bar{\beta} + u_{\nu_{jk}}(T_{ex})(1 - \bar{\beta}) \;\;\; ,
\end{equation}
where \mbox{$\bar{\beta}$}\ is the solid angle averaged escape fraction
(see Chapter 19 of Draine 2011 for a derivation). If we multiply the energy density
by the conversion factor between Einstein $B_{jk}$ and $A_{jk}$
terms from Equation 2, then we find that
\begin{equation}
\frac{c^3}{8\pi h\nu^3_{jk}} u_{\nu_{jk}} = n_{ph}(T_{bg},\nu_{jk})\bar{\beta}
+ n_{ph}(T_{ex},\nu_{jk})(1 - \bar{\beta}) \;\; .
\end{equation}
In the limit that
the background radiation can be ignored ($u_{\nu_{jk}}(T_{bg})\bar{\beta} \ll  u_{\nu_{jk}}(T_{ex})(1 - \bar{\beta})$),
the critical density becomes
\begin{eqnarray}
n_{crit}^{thick, no\; bg}  & = &  \frac{ n_j A_{jk} + n_j A_{jk} n_{ph}(T_{ex},\nu_{jk}) (1 - \bar{\beta})
- n_k \frac{g_j}{g_k} A_{jk} n_{ph}(T_{ex},\nu_{jk})(1 - \bar{\beta)}}
{n_j \sum_{i \neq j} \gamma_{ji} }
\nonumber \\
 & = &
\frac{ n_j A_{jk} \left[ 1 + (1 - \frac{g_j}{g_k}\frac{n_k}{n_j})n_{ph}(T_{ex},\nu_{jk})(1 - \bar{\beta}) \right] }
{n_j \sum_{i \neq j} \gamma_{ji}  }   \nonumber \\
& = &
\frac{ A_{jk} \left[ 1 + (\frac{-1}{n_{ph}(T_{ex},\nu_{jk})})n_{ph}(T_{ex},\nu_{jk})(1 - \bar{\beta}) \right] }
{\sum_{i \neq j} \gamma_{ji}  }   \nonumber \\
& = &
\frac{ \bar{\beta} A_{jk} }
{ \sum_{i \neq j} \gamma_{ji} } \;\;.
\end{eqnarray}
Comparing Equation 9 with Equation 4, we see that
the effect of radiative trapping is to reduce the spontaneous transition
rate by the escape
fraction \mbox{$\bar{\beta}$} $A_{jk}$ (see Scoville \& Solomon 1974, Goldreich \& Kwan 1974).

The relationship between \mbox{$\bar{\beta}$}\ and the line of sight optical depth, $\tau_{\nu_{jk}}$, depends on the geometry and kinematics
of the region.
In the case of a static, uniform density sphere
\begin{equation}
\bar{\beta} = \frac{3}{4\tau_{\nu_{jk}}} - \frac{3}{8\tau^3_{\nu_{jk}}} + e^{-2\tau_{\nu_{jk}}}\left( \frac{3}{4\tau^2_{\nu_{jk}}}
+ \frac{3}{8\tau^3_{\nu_{jk}}} \right)
\end{equation}
(Osterbrock 1989), while
in the case of a spherical cloud with a large velocity gradient $v \propto r$
(the LVG or Sobolev approximation),
\begin{equation}
\bar{\beta} = \frac{(1 - e^{-\tau_{\nu_{jk}}})}{\tau_{\nu_{jk}}}
\end{equation}
(Sobolev 1960, Castor 1970).
For large optical depths ($\tau_{\nu_{jk}} >\sim 5$),
the effective spontaneous transition rate is then given by
$\bar{\beta}A_{jk} \sim A_{jk}/\tau_{\nu_{jk}}$.

This result has an important effect on the critical density by reducing its
value from the optically thin value.  The most commonly observed transition
of molecular gas is $^{12}$CO $1-0$.  The optically thin
critical density at $T_k = 10$ K is $n_{crit}^{thin, no\; bg} = 1 \times 10^3$ cm$^{-3}$;
however, since $^{12}$CO $1-0$ has optical depths that are typically
more than a factor of $10$ in molecular clouds (and usually much higher),
it is easy to observe
strong lines ($> 1$ K km/s) in gas that has densities $< 10^2$ cm$^{-3}$.
Optical trapping is so important for CO that it does not make
sense to use the optically thin critical density.

Commonly observed lines of dense gas tracers in cores and clumps also
tend to be optically thick.
The upper left panel of Figure 3 shows the predicted
optical depth of HCO$^+$\ $1-0$ through $4-3$
at different densities from a simple (single density,
single temperature) radiative transfer model predicting that these
transition are expected to be very optically thick over a wide
range of densities.  Observations support this prediction.
For example, several hundred high-mass clumps mapped in the MALT90 Galactic survey
have a median optical depth of $\tau = 23$ for the HCO$^+$\ $1-0$ transition
(Hoq et al. 2013).  Clumps observed in the Bolocam Galactic Plane Survey (BGPS)
in the higher frequency transition HCO$^+$\ $3-2$ have an average $\tau = 10$
(Shirley et al. 2013).
As a result, the analytically calculated
critical densities using the optically thin approximation (Equation 4)
are systematically biased toward higher densities by an order of magnitude
or more.  HCO$^+$\ is not unique as most commonly observed dense gas tracers
(i.e. HCN, CS, N$_2$H$^+$, etc.)
in the dense, cold neutral medium are typically both sub-thermally populated
($T_{ex} < T_k$) and optically thick (also see Plume et al. 1997, Gerner et al. 2014).
In practice, to properly estimate
the optical depth, a coupled radiative transfer and
statistical equilibrium calculation must be performed to find the
level populations upon which the optical depth depends
(since $\tau_{\nu_{jk}} \propto \int (n_k B_{kj} - n_j B_{jk}) \, ds$ along
the line-of-sight $s$).
Since the escape fraction depends nonlinearly
with column density (for modest optical depths), nonlinearly with geometry, and
nonlinearly with gas kinetic temperature,
it is difficult to make a simple
tabulation of a \mbox{$\bar{\beta}$}\ correction to $n_{crit}^{thin, no\; bg}$.

\begin{figure}
\figurenum{3}
\epsscale{1.0}
\plotone{f3.eps}
\figcaption{
Top Left: Line of sight optical depth for HCO$^+$\ transitions.
A column density of $\log N = 14.0$ and a gas kinetic temperature
of $T_k = 10$ K were assumed.
Top Right: The integrated intensity for HCO$^+$\ transitions.
A column density of $\log N = 14.0$ and a gas kinetic temperature
of $T_k = 10$ K were assumed.
The horizontal dashed line is the criterion for the definition of
\mbox{$n_{eff}$}\ used in this paper.
Bottom Left: $n_{eff}$
is inversely proportional column density.
Only the HCO$^+$\ $1-0$ and $4-3$ transitions
are shown for clarity.  The solid line is calculated at $T_k = 20$ K while the dashed
lines above and below the solid line correspond to $T_k = 10$ K and $T_k = 30$ K.
Bottom Right: The dependence of
$n_{eff}$ on choice of gas kinetic temperature for the four lowest rotational transitions
of HCO$^+$ .  $n_{eff}$ was calculated assuming the reference column density of
$\log N = 14.0$.}
\end{figure}

\section{Effective Excitation Density}

It is possible to detect strong ($1$ K km/s) molecular lines at densities
well below the critical density (see Figure 3).
An alternative definition has been developed to
trace the effective density at which a modest line intensity is observed that is
based on radiative transfer calculations with reasonable assumptions
about the column density and gas kinetic temperature of the region (Evans 1999).
The effective excitation density is defined as
\begin{equation}
n_{eff} = n_c \; \ni \; \int T_R \, \mathrm{dv} = 1 \; \rm{K} \, \rm{km/s} \;\;\; ,
\end{equation}
the density which results in a molecular line with an integrated intensity of $1$ K km/s.
The choice of $1$ K km/s is arbitrary but represents an easily detectable integrated intensity
\footnote{The radiation temperature is related to the observed flux density $S_{\nu_{jk}}$
through $T_R = \frac{c^2}{2k\nu_{jk}^2\Omega_{beam}} \, S_{\nu_{jk}}$ where
$\Omega_{beam} = \frac{\pi \theta_{beam}^2}{4 \ln 2}$ is the solid angle of the telescope
beam with FWHM $\theta_{beam}$.  A $1$ K km/s integrated intensity corresponds to
an integrated flux density of $0.818$ Jy km/s $(\frac{\nu_{jk}}{100 \rm{GHz}})^2 \, (\frac{\theta_{beam}}{10^{\prime\prime}})^2$.}.
For lower integrated intensity criteria, \mbox{$n_{eff}$}\ decreases (Figure 3).
It is important to note
that the effective excitation density is based on a simple empirical criterion and is not
based on $\Re = 1$ or any specific ratio of radiative rates
to collisional depopulation rates.  \mbox{$n_{eff}$}\ does however account for the effects of
radiative trapping.
The original definition presented in Evans (1999) defined $n_{eff}$ as the density
resulting in $T_R = 1$ K line and used a LVG radiative transfer code to calculate
$n_{eff}$.
We shall use the radiative transfer code RADEX
(van der Tak et al. 2007)
with the escape probability formalism for a static, uniform density sphere,
with the CMB as the only background radiation field, and with H$_2$ as the
dominant collision partner for all calculations.
The definition in Equation 12 is approximately equivalent to the Evans 1999 definition
when a FWHM linewidth of 1 km/s is assumed in RADEX calculations.

\subsection{Properties of Effective Excitation Density}

The column density of the observed molecule
and the gas kinetic
temperature of the colliding partner must be assumed in order to calculate \mbox{$n_{eff}$} .
The sensitivity of \mbox{$n_{eff}$}\ to these assumptions is explored in Figure 3 for the
HCO$^+$\ molecule.
At lower column densities, a higher \mbox{$n_{eff}$}\ is required to produce a
$1$ K km/s line.  As the column density increases by an order of magnitude, the \mbox{$n_{eff}$}\
decreases by almost exactly an order of magnitude.
The effective excitation density is inversely proportional to column density
\begin{equation}
n_{eff}(T_k,N) \approx n_{eff}(T_k,N_{ref}) \, \frac{N_{ref}}{N} \;\;\; ,
\end{equation}
where $N_{ref}$ is a reference column density.  This simple scaling
proportionality breaks down for $n_{eff} \gtrsim 5 \times 10^6$ cm$^{-3}$
and the relationship between \mbox{$n_{eff}$}\ and $N$ becomes noticeably non-linear
(see the $T_k = 10$ K curve for HCO$^+$\ $4-3$ in the bottom left panel of Figure 3).
In those cases, a new RADEX model should be run to scale tabulated results
to a new column density.

The dependence of \mbox{$n_{eff}$}\ to $T_k$ is nonlinear and
more sensitive at low kinetic temperatures ($T_k < 20$ K)
due to the inefficiency of upward collisions at lower $T_k$ (Figure 3).
An order of magnitude higher
\mbox{$n_{eff}$}\ is required to make a $1$ K km/s line for $T_k = 10$ K than
at $T_k = 30$ K for HCO$^+$\ $3-2$.  This sensitivity is due to the exponential dependence
from upward collisional rates (Equation 4) and becomes more pronounced when the upper energy level
is significantly
higher than $T_k$ (i.e. the effect is stronger for $4-3$ vs. $1-0$ at $T_k < 20$ K
because $E_u/k = 42.8$ K for J = 4 vs. $E_u/k = 4.3$ K for J = 1).

Table 1 gives $n_{eff}$ for $12$ dense gas tracers
at $T_k$ = 10, 15, 20, 50, and 100 K for a reference
column density.
Recent surveys of dense gas in the Milky Way may be used to guide
our choice of the reference column density.  For example, observations of several hundred clumps
by the MALT90 (Meittenen et al. 2013, Hoq et al. 2013), ChaMP (Barnes et al. 2012),
and BGPS (Shirley et al. 2013) surveys indicate that HCO$^+$\ column densities
typically span from $\log N = 12 - 15.5$.  The Hoq et al. and Shirley et al. surveys
find median column densities of clumps drawn from the ATLASGAL and BPGS
Galactic plane surveys that are in agreement near $\log (\rm{med}\{N\}) = 14.4$.
Miettenen's (2014) analysis of infrared dark clouds (IRDCs) indicates a significantly
lower median column density of $\log (\rm{med}\{N\}) = 13.1$.  All of these
surveys use observations of H$^{13}$CO$^+$ to correct the optical depth of the HCO$^+$\ line.
The Barnes et al. (2011) blind mapping survey of a section of the southern Galactic plane find a
smaller value of $\log (\rm{med}\{N\}) = 12.9$, but did not observe H$^{13}$CO$^+$
to make optical depth corrections.
We chose a column density that is intermediate
between the IRDC, low-mass samples, and the Galactic plane surveys of
$\log (N_{ref}) = 14.0$.  For comparison, Evans (1999) tabulate the effective density for
HCO$^+$\ assuming $\log N = 13.5$.

The reference column densities for each molecule in Table 1 are estimated
from surveys in dense gas tracers  (Suzuki et al. 1992, Zylka et al. 1992,
Mangum \& Wootten 1993, Plume et al. 1997, Jijina et al. 1999, Savage et al. 2002,
Pirogov et al. 2003, Purcell et al. 2006, Blair et al. 2008, Rosolowsky et al. 2008,
Falgarone et al. 2008, Hily-Blant et al. 2010, Barnes et al. 2011, Dunham et al. 2011,
Ginsburg et al. 2011, Reiter et al. 2011,
Adande et al. 2012, Benedettini et al. 2012, Wienen et al. 2012,
Hoq et al. 2013, Shirley et al. 2013, Gerner et al. 2014,  Miettenen et al. 2014
Yuan et al. 2014).  Since these surveys contain many biases (i.e. only
study massive high-mass regions or only study
nearby low-mass regions, etc.), $N_{ref}$ represents an educated guess at a typical value
intermediate between high-mass clumps and low-mass cores.
The tabulated $n_{eff}$ can be easily scaled to another column density using
Equation 13.
$^{13}$C isotopologue column densities assume
no fractionation and an isotope ratio of $[^{12}\rm{C}]/[^{13}\rm{C}] = 50$,
appropriate for a source in the Molecular Ring (Wilson \& Rood 1994).
For molecules with ortho and para states, LTE statistical equilibrium was
assumed ($2:1$ ortho to para ratio for NH$_3$ and $3:1$ ortho to para ratio for
H$_2$CO).

\subsection{Comparing Critical Density and Effective Excitation Density}

The panels of
Figure 4 summarize the range in $n_{crit}^{thin, no\; bg}$ and $n_{eff}$ of commonly observed
molecular tracers of dense gas for reference observed column densities and a gas kinetic temperature
of $T_k = 15$ K.  This temperature was chosen to be intermediate between the
typical temperature of nearby low-mass cores ($10$ K, Jijina et al. 1999, Rosolowsky et al.
2008, Seo et al. 2015, submitted)
and high-mass clumps in the Galactic plane ($20$ K, Dunham et al. 2011, Wienen et al. 2012).
$n_{eff}$ is lower than $n_{crit}^{thin, no\; bg}$ in nearly all cases by $1 - 2$ orders of
magnitude.  This is partially due to the sensitivity of $n_{eff}$ to line trapping in optically
thick transitions.  Transitions that are the most optically thick
have the largest average $n_{crit}^{thin, no\; bg} / n_{eff} $ ratios (i.e
$121$ for HCO$^+$\ transitions and $88$ for HCN transitions where the
average is calculated for $1-0$ through $4-3$ transitions).
Less optically thick species have smaller ratios
(i.e. average ratios of $16$ for CN and $10$ for N$_2$H$^+$).
The species plotted with the smallest difference between
$n_{crit}^{thin, no\; bg}$ and $n_{eff}$ is the optically thin isotpologue H$^{13}$CN
with an average ratio of $1.7$.
Some heavier species whose transitions are likely close to
optically thin listed in Table 1 also have low average ratios that are less than $3$ (i.e.
H$_2$CO, HC$_3$N, and CH$_3$CN).
These results indicate that a $1$ K km/s line is typically observed for transitions when
$\Re > 1$ in Equation 1 or when the radiative rates are greater than collisional depopulation
out of the upper energy level of the transition.

There is also typically an increase in $n_{crit}^{thin, no\; bg}$ and $n_{eff}$ with
$J_u$ for a particular molecule (Figure 4).
This behavior can be understood from the functional dependences on $A_{jk}$
and $\gamma_{jk}$ in Equation 4
($n_{crit}^{thin, no\; bg}$ $\sim A_{jk}/\gamma_{jk}$).
The Einstein $A$ for electric dipole allowed transitions is
$A_{jk} \propto \mu_e^2 \nu_{jk}^3$, where $\mu_e$ is the molecular
permanent electric dipole moment.  In general, molecules with larger $\mu_e$ will trace
denser gas. For instance, $\mu_e = 2.99$ D for HCN while $\mu_e = 0.11$ D for CO
(Ebenstein \& Muenter 1984, Goorvitch 1994), partially explaining why HCN is a denser gas tracer
than CO (the other effect being that the optical trapping in $^{12}$CO lines is often very large;
see \S2.2).
Since $\nu_{jk} \propto J_u$ and the Einstein $A_{jk}$ has a $\nu_{jk}^3$ dependence,
higher frequency transitions of a particular molecule
will trace higher densities.  This statement is also true for comparing molecules with similar
permanent electric dipole moments but with transitions at different frequencies.
As an example, the frequency of the NH$_3$ ($\mu_e = 1.47$ D; Ueda \& Iwahori 1986) inversion transitions
(J,K=J) are nearly a factor of $4$ lower than for the $1-0$ transitions of
HCO$^+$\, N$_2$H$^+$\, and HCN, thus the spontaneous transition rate is more than $60$ times smaller,
lowering the critical densities of NH$_3$ (1,1) with respect to the
$1-0$ transitions of HCO$^+$\, N$_2$H$^+$\, and HCN.  One problem with the use of
$n_{crit}^{thin}$ becomes apparent for the NH$_3$ inversion transitions.  Since
NH$_3$ (1,1) through (4,4) are at nearly the same frequency ($23.7$ to $24.1$ GHz),
their $n_{crit}^{thin, no\; bg}$ are nearly identical.  $n_{eff}$ is sensitive to both line trapping
and $E_u/k$ of the transition resulting in an increase in $n_{eff}$ for NH$_3$ (1,1)
and (2,2) (N.B. \mbox{$n_{eff}$}\ for NH$_3$ (3,3) and (4,4) are
undefined at $T_k = 15$ K as we will discuss below).

Differences in collision rates also affect the ranking of molecules with density
in Figure 4.  HCN is observed to have 1 - 2 orders of magnitude
higher $n_{crit}^{thin, no\; bg}$ and $n_{eff}$ than HCO$^+$.
Both HCO$^+$\ and HCN transitions have similar $A_{jk}$ values, but HCO$^+$\ is an
ion and the collisional cross section for collisions with H$_2$ is larger
than for neutral species (see Flower 1999 vs. Dumouchel et al. 2010).
This reduces the critical density and effective
excitation density of HCO$^+$\ relative to HCN.

\begin{figure}
\figurenum{4}
\epsscale{1.0}
\plotone{f4.eps}
\figcaption{
Left: $n_{crit}^{thin, no\; bg}$ calculated at $T_k = 15$ K for popular dense gas
tracers.  Each point corresponds to the upper state rotational quantum number J of
the transition. The ordering of labels correspond to the ordering of the curves in increasing
density for
each molecule.  Note that the curves for
HCO$^+$\ and N$_2$H$^+$ nearly overlap as well as for CN and H$^{13}$CN.
Right: $n_{eff}$ calculated for $T_k = 15$ K and at the reference
column density determined from surveys of Galactic sources (see Table 1).
Note that the curves for HCN and N$_2$H$^+$ nearly overlap.
The critical density is typically one to
two orders of magnitude above $n_{eff}$ for these tracers.}
\end{figure}

The ordering of species with increasing density is different
for $n_{crit}^{thin, no\; bg}$ versus $n_{eff}$ among many of the molecules plotted in Figure 4.
A problem with using $n_{crit}^{thin, no\; bg}$
can be seen when HCO$^+$\ and N$_2$H$^+$\ are compared.
HCO$^+$\ and N$_2$H$^+$\ are both ions
with similar $A_{jk}$ values for transitions and similar collisional cross-sections
and thus have similar $n_{crit}^{thin, no\; bg}$; however,
it is common knowledge to observers
of nearby, low-mass dense cores that N$_2$H$^+$\ is a denser gas tracer than HCO$^+$ .
Due to chemical effects, N$_2$H$^+$\ typically has lower abundance and therefore lower column
density than HCO$^+$\ resulting in a higher \mbox{$n_{eff}$}\ (see Equation 13).

\mbox{$n_{eff}$}\ also does a better job than $n_{crit}^{thin, no\; bg}$
of characterizing the difference in density traced by isotopologues
versus the main species.
The ratio of $A_{jk}$ for the $1 \rightarrow 0$ transition
between H$^{13}$CN and HCN is $0.92$.
This accounts for the slightly lower $n_{crit}^{thin, no\; bg}$ for H$^{13}$CN versus HCN;
however, we know that the isotopologues
should trace higher density gas than the main species because it is more optically thin
and has a lower column density (see Equation 13).
The average ratio of \mbox{$n_{eff}$}\ for H$^{13}$CN/HCN $1 \rightarrow 0$
is $41$ ($T_k \in [10,100]$ K).  This ratio is
not exactly equal to the assumed isotope ratio and column density ratio of $50$
because of differences in $A_{jk}$, collisional rates, and line trapping
between the isotopologue and main species.

These examples illustrates important
advantages in using \mbox{$n_{eff}$}\ rather than the critical density;
however, using $n_{eff}$ has a significant disadvantage
in that \mbox{$n_{eff}$}\ is undefined when an integrated intensity of 1 K km/s cannot be observed.
This is the case for the NH$_3$ (3,3) ($E_u/k = 123.5$ K) and higher inversion lines at
low gas kinetic temperature.
When $E_u/k \gg T_k$, the upper energy state cannot attain a high enough population
to result in large enough radiative rates to produce a $1$ K km/s line.
High $J_u$ transitions for species such as NH$_3$, HCN, HCO$^+$ , and N$_2$H$^+$\
will be undefined at low gas kinetic temperatures $(T_k \lesssim 20$ K).

Another problem with the standard definition of $n_{eff}$ is that the
more complex the spectrum of a molecule (e.g. a heavy asymmetric top
molecule), the less likely a particular transition will attain enough level population
to produce a $1$ K km/s emission line.  For instance, no transitions of
HNCO have intensities greater than $1$ K km/s for the observed
median column density of $\log \rm{med}\{N\} = 12.6$ (Gerner et al. 2014).
$n_{eff}$ for complex organic species (i.e. CH$_3$CHO, CH$_3$OCH$_3$, etc.) will be
undefined.  One solution is to reduce the $1$ K km/s criterion,
Ultimately, the choice for this criterion is arbitrary, but
unless all researchers agree to use the same criterion, $n_{eff}$ could
not be compared among different papers and for different species.
The upper right panel of Figure 3 shows the non-linear sensitivity
of the integrated intensity for different transitions of HCO$^+$\
with density.  As the integrated intensity criterion is lowered, the
curves flatten with $n_c$ indicating that a smaller decrease in the criterion results
in a larger decrease in $n_{eff}$.
These problems limit the utility of $n_{eff}$ compared to $n_{crit}^{thin, no\; bg}$ which
can always be calculated if collision rates are known.

\section{A Caveat About Continuum Radiation Backgrounds}

We ignored continuum background radiation fields in \S2 when deriving the
expressions for $n_{crit}^{thin, no\; bg}$ and $n_{crit}^{thick, no\; bg}$,
while only the CMB was considered as a background in the RADEX models in \S3.
In this section we consider when contributions from the CMB and dust
continuum background are important.

The ratio of the rate of stimulated
emission from $j \rightarrow k$ due to the CMB to spontaneous emission is given by
\begin{equation}
\frac{B_{jk} u_{\nu_{jk}}(T_{cmb})}{A_{jk}} = \frac{1}{e^{h\nu_{jk}/kT_{cmb}} - 1} = n_{ph}(T_{cmb},\nu_{jk}) \;\; .
\end{equation}
This ratio is $2$ for the NH$_3$ (J,K=J) inversion transitions and is a modest $0.26$
at 90 GHz (3.3 mm), near the frequency of the fundamental transitions of commonly
observed dense gas tracers (e.g. HCO$^+$ , HCN, HNC, N$_2$H$^+$ ).  This ratio
drops below $0.1$ for transitions with $\nu_{jk} > 140$ GHz ($\lambda_{jk} < 2.1$ mm).
Table 1 lists $n_{ph}(T_{cmb},\nu_{jk})$ for each transition.
For low frequency (long wavelength) transitions, stimulated emission and absorption
due to the CMB should not be ignored.

Interesting examples of the interaction of low frequency transitions with the
CMB are the K-doublet transitions of ortho-H$_2$CO
($1_{1,0} - 1_{1,1}$, $2_{1,1} - 2_{1,2}$, etc.).  The
$4.6$ GHz ($6.5$ cm) $1_{1,0} - 1_{1,1}$ transition has a stimulated emission
rate to spontaneous emission rate ratio of $11.3$.
Since the statistical weights of the two level are
identical, the absorption rate from the lower level is identical
to the stimulated emission rate from the upper level.
This line is typically observed in absorption for
densities $n \lesssim 10^{5}$ cm$^{-3}$ (Mangum et al. 2008).
The absorption is created by the lowest energy level ($1_{1,1}$) having
a collisionally-induced overpopulation that results in absorption against the CMB
($T_{ex} < T_{cmb}$)
over a wide range of physical conditions (Evans 1975, Garrison 1975).
The calculation of $n_{crit}^{thin,no\; bg}$ gives a ridiculously low value of
$13$ cm$^{-3}$ at $T_k = 10$ K.
Clearly in cases such as these, the simple definition of critical density fails
and more sophisticated radiative transfer and statistical equilibrium calculations
that include the CMB background are required.

In addition to the CMB, dust continuum backgrounds from the Galactic interstellar
radiation field
and from emission local to the cloud can be important in modifying the level
populations.  The main effect of dust continuum emission on our definition
of critical density is to introduce a new stimulated rate out of level $j$
to higher energy levels, $i$.
The energy density is now the energy density for optically thin dust emission
\begin{equation}
u_{\nu_{ij}}^{dust}(T_{dust}) = \tau_{\nu_{ij}}^{dust} u_{\nu_{ij}}(T_{dust}) \;\; ,
\end{equation}
where $\tau_{\nu_{ij}}^{dust}$ is the dust optical depth at
the frequency of the $i \rightarrow j$ transition and
$T_{dust}$ is the isothermal dust temperature (see Equation 4 of Shirley et al. 2011 for
a derivation of the equivalent isothermal dust temperature at a given frequency
in sources with density and temperature gradients).
We only need to consider transitions
between $i \rightarrow j$ that are allowed by electric dipole selection rules
because the Einstein $B_{ji}$ for absorption of $j \rightarrow i$
is directly proportional to the Einstein $A_{ij}$ for spontaneous emission
of $i \rightarrow j$ (see Equation 2).
For many simple molecules (HCO$^+$ , N$_2$H$^+$ , HCN, CS, NH$_3$, etc.)
there is only one electric dipole
permitted transition from $j$ into the upper state $i$ that needs
to be considered.
The ratio of the rate at which this absorption from $j \rightarrow i$
occurs to the spontaneous rate
for the original $j \rightarrow k$ transition is
\begin{eqnarray}
\frac{B_{ji} u_{\nu_{ij}}^{dust}}{A_{jk}} & = &
\frac{g_i}{g_j}\frac{A_{ij}}{A_{jk}}\frac{\tau_{\nu_{ij}}^{dust}}{\exp(h\nu_{ij}/kT_{dust}) - 1}
\nonumber \\
& = &
\frac{g_i}{g_j}\frac{A_{ij}}{A_{jk}} \mu m_{\rm{H}} N_{\rm{H}_2} \kappa_{\nu_{jk}}
n_{ph}(T_{dust}, \nu_{ij}) \;\; ,
\end{eqnarray}
where $\mu = 2.8$ is the mean mass per H$_2$
molecule (see Kauffmann et al. 2008), $N_{\rm{H}_2}$ is the H$_2$ column density (cm$^{-2}$),
and $\kappa_{\nu_{jk}}$ is dust opacity (cm$^2$/gram of gas) at the frequency
of the $j \rightarrow i$ absorption.
The ratio of rates in Equation 16 is linear proportional
to the H$_2$ column density and increases non-linearly with dust temperature.

For the following examples, we calculate the ratio of rates in Equation 16
assuming a H$_2$ column density of $10^{22}$ cm$^{-3}$ (corresponding
to $A_V \sim 10$ mag), a gas mass to dust mass
ratio of $100:1$, and Ossenkopf \& Henning opacities for coagulated grains
with thin ice mantles (OH5, Ossenkopf \& Henning 1994) that are
appropriate for dense cores.
For the NH$_3$ (1,1) transition, the upper level is radiatively coupled to
the $J = 2, K = 1$ level via a 1.168 THz ($267$ $\mu$m) far-infrared transition (see Figure 1).
If NH$_3$ is bathed in a dust continuum of $10$ K,
the stimulated rate of absorption out of the
upper inversion level is four times the spontaneous rate of the (1,1) transition.
This high ratio is partially driven by the ratio of
spontaneous rates between the terahertz transition and the centimeter inversion transition
which is $A_{ij}/A_{jk} = 7.2 \times 10^5$.
The net effect is that \mbox{$n_{eff}$}\ becomes larger as the energy density from dust continuum
increases.
When the upper level of a low frequency transition is radiatively coupled to far-infrared
transitions, the absorption from dust continuum is an important
rate that should not be ignored.
This is the case for the centimeter transitions of molecules such as NH$_3$, OH, and CH.

The effects of dust continuum radiation are significantly less
for the lowest energy transitions of simple linear molecules.
For the $267.5$ GHz (1.1 mm) HCO$^+$\ $3-2$ transition at $10$ K, the
ratio of rates is $6 \times 10^{-4}$.
At 50 K, the ratio of rates rises to a meager $7 \times 10^{-3}$.
These very low ratios indicate
that the absorption due to dust continuum emission
is not important for the level populations associated with
millimeter transitions of linear molecules such as HCO$^+$, HCN, CS, and N$_2$H$^+$ .

We have only considered the rotational
levels of the molecule, but there can also be coupling between the radiation
field and vibrational levels or electronic levels
of the molecule that can effect the level populations
of the ground vibrational state rotational levels.  A mid-infrared
continuum can pump the molecule from the ground vibrational state into
an excited vibrational state which then radiatively decays via ro-vibrational
transitions.  For example, the HCN and HNC molecules have bending modes
($\nu_1,\nu_2,\nu_3 = 0,1,0$) that can be excited
by mid-infrared pumping at $14$ $\mu$m and $21$ $\mu$m respectively.
In environments where such pumping may be important (i.e. the inner envelope of
high-mass protostars or near an AGN), the level populations can be affected
by mid-infrared pumping.  In these cases, more sophisticated radiative
transfer models are needed.

\section{Summary}

In this tutorial, $n_{crit}^{thin, no\; bg}$ and \mbox{$n_{eff}$}\ are defined and their
properties analyzed.  The values for $n_{crit}^{thin, no\; bg}$ and \mbox{$n_{eff}$}\ are
calculated for multiple transitions of
12 commonly observed dense molecular gas species in Table 1.
\mbox{$n_{eff}$}\ inversely depends on the choice of column density and increases non-linearly
as gas kinetic temperatures are lowered ($T_k < 20$ K).  We have estimated
the reference column density for difference species listed in Table 1 from surveys of
cores and clumps
in the Milky Way.  The \mbox{$n_{eff}$}\ quoted can be easily scaled to another column density
using Equation 13.

Since the definition of \mbox{$n_{eff}$}\ is arbitrary (the $1$ K km/s criteria) and does not
depend on a specific ratio of radiative rates to collisional depopulation rates
(c.f. $\Re = 1$ for the definition of $n_{crit}$),
it is seductive to use $n_{crit}^{thin, no\; bg}$ to characterize
the density at which a transition is excited as it
can be analytically calculated; however, $n_{crit}^{thin, no\; bg}$ does
not account for radiative trapping which can easily lower the effective critical
density by more than an order of magnitude for commonly observed dense gas tracers
such as HCO$^+$\ $1-0$, HCN $1-0$, N$_2$H$^+$\ $1-0$, etc.
The combination of $\Re > 1$ and radiative trapping that generate a $1$ K km/s line
lower \mbox{$n_{eff}$}\ by $\sim 1 - 2$
orders of magnitude relative to $n_{crit}^{thin, no\; bg}$ for many commonly
observed millimeter and submillimeter lines.
Furthermore, \mbox{$n_{eff}$}\ can account for abundance or column density differences
to better differentiate the excitation density of different species than
$n_{crit}^{thin, no\; bg}$ (i.e. HCO$^+$\ vs. N$_2$H$^+$\ or isotpologues vs. the main species).
Overall, the effective excitation density gives a better estimate of the
range of densities at which a modest (1 K km/s) molecular line can be observed;
however, use of $n_{eff}$ has the disadvantages that an appropriate column density must be
determined for the observations of interest and that it is not defined for all transitions
(in particular when $E_u/k \gg T_k$) and for all species (e.g. HNCO, CH$_3$CHO, etc.).

$n_{crit}^{thin, no\; bg}$ and \mbox{$n_{eff}$}\ provide only rough
estimates of the densities traced and should not be over-interpreted.
More sophisticated tools such as the Contribution Function
(Tafalla et al. 2006) may be used to determine the various contributions to
the observed line profile along the line of sight (see Pavlyuchenkov et al. 2008
for a detailed analysis of these techniques).
Ultimately, if one wants to understand their observed spectra, radiative transfer
modeling with publicly available codes are a fast and efficient way to determine the
physical properties of a region.

\section*{Acknowledgments}

I am grateful to the Max-Planck-Institut f\"ur Astronomie and Thomas Henning
for hosting my Sabbatical during which this note was written.
I would also like to thank John Black, Lee Mundy, Neal Evans, Henrik Beuther,
Cecilia Ceccarelli, J.D. Smith, and the anonymous referee for
comments and useful discussions that improved this manuscript.

\newpage

redpajama_set_name: RedPajamaArXiv


Al Qaeda attacked and seized a hotel in Burkina Faso on Friday, killing at least 28. Those who know the history of the terror group know that it was funded (if not created from whole cloth) by the US government back when they were called the "Mujaheddin".
The waning Pallas-Pluto conjunction (currently bridged by the Sun and Mercury) is a "gift that keeps on giving". One hopes that once the conjunction has fully broken up, the long Saturn-Pluto parallel this year (Saturn co-rules Pallas in Aquarius/Capricorn for much of the year) will be too weak to trigger major bloodshed.
1. Pallas conjunct Pluto via stellium, Pallas ruler Saturn parallel Pluto.
2. Venus widely/indirectly square Neptune and square the Nodes.
There is (of course) a Pluto-to-Pallas transit against the chart of Burkina Faso, with transiting Pluto conjunct both natal and progressed Pallas. This nation rarely makes the news in the US, even in the alt-press. Consistent with this Pluto transit to Pallas, the country has recently endured violent protests and a failed coup attempt.


FALUN, Sweden (AP) Jessie Diggins finds herself in a unique situation for an American cross-country skier: trying to defend a world championship title.
Diggins teamed with Kikkan Randall to win the women's team sprint at the 2013 worlds in Val di Fiemme, Italy, becoming the first Americans to win a gold medal in the sport.
On Sunday, Diggins will compete in the same event with a different teammate - Sophie Caldwell - but has hopes of surprising the bigger nations again.
Randall has traditionally been the team's star and is a two-time sprint World Cup champion. However, she has struggled this season and was dropped in favor of Caldwell for the team sprint. Caldwell, of Peru, Vermont, was the best American finisher in the individual classical-style sprint on Thursday when she finished 10th. Randall failed to make it out of qualifying for the quarterfinals, while Diggins - a freestyle specialist - didn't compete.
Despite being the defending champion, the American team is hardly considered the favorite for gold. Norway has that status, despite six-time Olympic champion Marit Bjoergen skipping the event. Norway instead has Maiken Caspersen Falla teaming with Ingvild Flugstad Oestberg, the gold and silver medalists from the individual freestyle sprint at the Sochi Olympics.
But sprint races are notoriously unpredictable because of the many spills and crashes that can happen. And that means the Americans certainly have a chance at repeating.


We often find ourselves in an endless cycle of deadlines and wasted time. Procrastination is a habit that is hard to break, but no one ever said it was impossible. The best way to stay committed to your responsibilities is to have schedule templates that will prepare you for what's to come.
Effective scheduling is something you can improve over time. So in this article, let's look into the major components of a schedule along with a few tips to help you make one.
Heading: The heading will tell you what the schedule is for. You can also use this section to note down instructions or reminders to keep you guided as you go about with your day.
Date: A schedule is typically designed like a calendar to show the time frame of events or tasks that are set to take place. Since most of your responsibilities are specific to a given day, you must specify the exact date as to when a particular activity must be completed.
Time: One of the best ways to avoid conflict between appointments and other obligations is to allocate the exact time to work on each activity. This offers you a glimpse of the amount of time you have to carry out a task and what other assignments may be added to your list of to-dos.
Tasks: The primary objective of a schedule is to record your plans for a given span of time. This may include scheduled appointments, personal gatherings, business meetings, and other engagements. It's important to prioritize your tasks properly to stay focused and productive.
1. List down important tasks and events for the period: A great way to stay organized and committed to your schedule is to begin with a task checklist. This prepares you for whatever circumstances you are set to face in the coming days. Make sure to focus on important activities before you fill in your schedule with useless endeavors.
2. Prioritize essential items: Among the many tasks of your daily routine, lies a few errands and appointments that need to be attended to. The best way to deal with these obligations is to distinguish what's important from what's not on your list. Once identified, you must highlight these items for reference.
3. Keep it flexible: Minor inconveniences and unforeseen circumstances can cause a few changes to your schedule. Knowing this, it's important to set time allowances between activities to make sure you don't fall behind.
4. Avoid multitasking: This is a practice you should never consider doing, as this may lead to poor performance and risky outcomes. One way to avoid this is to make sure your schedule is realistic. An employee schedule, for example, must take an individual's capacity to complete the job into account.
Hourly Schedule: Activities in this type of schedule are noted down by the hour. An hourly schedule allows you to break down a huge list of tasks into smaller, more manageable parts for better execution. This also makes it easier to monitor what you have managed to accomplish within a 24-hour interval.
Daily Schedule: A daily schedule gives you a good look at your daily agenda by offering you a to-do list of activities. The items included in the schedule may be recurring or specific for that particular day, depending on one's usual routine.
Weekly Schedule: This type of schedule is perfect for instances that simply require a summary of tasks and activities for the week. Although weekly schedules tend to be a bit broad, they still provide enough information to keep you on track.
Monthly Schedule: The items plotted on a monthly schedule are usually recurring affairs from the previous months or those following it. Working professionals who have responsibilities and deadlines to meet often use a monthly schedule to set their deliverable in advance.
Yearly Schedule: What's great about a yearly schedule is how it offers a bird's-eye view of all the things that have happened or are set to happen in a year.
A schedule is a timetable used to track and manage the tasks and deliverable of a project. Here, a list of activities and events are arranged in a particular sequence for readers to know what to prioritize and when to fulfill an assignment.
A schedule is a popular time management tool that provides an overview of one's agenda for a given period. This helps users monitor past, present, and future plans in an attempt to avoid a waste in resources. A good time management schedule also motivates productivity by organizing tasks and activities accordingly, leaving you with enough time to focus on other obligations.
With the help of proper scheduling, you can maximize the time on your hands more wisely. Achieve your personal goals today by creating a schedule with the help of the templates provided in Google Docs format.


Have You Considered Fostering Or Adoption ?
Home > Event > What The Friday?
WHAT THE FRIDAY!? Start your weekend in STYLE!
£1.50 selected DRINKS till 1am! WTF! Fridays just got a whole lot CRAZIER!!
Welcome to PrideWest. Our Mission is to be the best online resource for Lesbian, Gay, Bisexual & Transgender people in the Bristol, Wiltshire & Somerset areas. Our site contains local LGBT news, a What's On guide, Scene Maps and links to health & support groups in the local area.


Habersham County School District offers competitive employee salaries.
Regular assessments of positions and pay practices are performed to ensure marketplace comparability and equality within the district. The Board of Education approves all certified and classified employee Salary Schedules annually as part of the fiscal year budget process. Approved schedules are posted here for the purposes of explaining and deriving salaries and do not constitute an offer of employment.
Pay day is the last working day of each month. Exceptions may be granted for November and December based on available revenue.
All new hire employees receive a Salary Sheet at their New Hire Orientation meeting. Every school system employee receives an updated salary sheet annually either in July, August, or September, as applicable.
An Employee Work Calendar is created each fiscal year showing the first work day and the last work day for each position in the school system. Payroll calendars are also created each year detailing the pay period dates, the cutoff dates, and pay dates.
12 month employees work between 218 & 261 days and are paid in 12 equal installments. Pay cycle begins July 1 and ends June 30.
11 month employees work between 200 & 209 days and are paid in 12 equal installments. Pay cycle begins August 1 and ends July 31.
10 month employees work between 180 & 200 days and are paid in 12 equal installments. Pay cycle begins September 1 and ends August 31.
Bus Drivers work 180 days and are paid in 12 equal installments. Pay cycle begins August 1 and ends July 31.
Salary for first year classroom teachers and paraprofessionals is paid in 13 equal installments for year 1 (August thru August). Year 2 pay cycle begins September 1 and ends August 31.
Please follow the instructions below to figure your salary estimate. Actual salary figures are subject to verification of employment and applicable job duties and responsibilities.


The Vacant Home Tour (VHT) was founded in 2014 by students at Carnegie Mellon University, and has since found a home in Wilkinsburg. Wilkinsburg has the highest vacancy rate in Allegheny County. With nearly 800 vacant parcels in 2.3 square miles, the VHT aims to address this problem in a way no one — in our region or anywhere else in the world — has before.
Through storytelling, tour goers learn about Wilkinsburg and the people who lived and worked here by interacting with those that currently do. The properties featured on the tour have been blighted for years, decades even, but not always. People once cared for them. The circumstances that led to the homes' vacancy is different, but the result is much the same. Blight negatively affects communities, not just because it's dangerous, but because it can make residents feel hopeless.
In the Tools & Resource Workshops offered during the tour, residents or tour-goers can learn about the available programs to acquire and rehab vacant properties. In this way, the VHT empowers the community by giving them tools to fight blight in their neighborhood. Though workshops required RSVP, those interested in vacant property can visit the vendor area or seek help at the Wilkinsburg Community Development Corporation anytime throughout the year.
Our hope us that you learn something new about Wilkinsburg, that you learn useful tools to engage vacant property, and that, if you don't already, you come to love this place as much as we and our tour guides and volunteers do. Wilkinsburg is Good All Over, and we're excited to show you why.


text:
Рамзен () — коммуна в Швейцарии, в кантоне Шаффхаузен.

Население составляет 1316 человек (на 31 декабря 2006 года). Официальный код — 2963.

Ссылки
 Официальная страница

redpajama_set_name: RedPajamaWikipedia


If love is a wire; then we end up electrocuted.
feel like, I'm dying inside.
My love for you will not die.
Harped by her eyes; you become unstrung.
as the pages turn slowly.
in a smile, a wave and a blink.
doesn't mean; it is not there.
until it comes out into the open.


I often joke that I've just become a professional schmoozer. Like, nobody cares how well I can rock climb anymore. It just has to do with how well I can schmooze.
I've tried to approach environmentalism the same way I do my climbing: by setting small, concrete goals that build on each other.
We are apes - we should be climbing.
I've done routes where I've climbed 200 feet off the ground and just been, like, 'What am I doing?' I then just climbed back down and went home. Discretion is the better part of valor. Some days are just not your day. That's the big thing with free soloing: when to call it.
I've never really understood the criticism that climbing is inherently selfish, since it could equally be argued about virtually any other hobby or sport. Is gardening selfish?
To be clear, I normally climb with a rope and partner. Free-soloing makes up only a small percentage of my total climbing. But when I do solo, I manage the risk through careful preparation. I don't solo anything unless I'm sure I can do it.
Yosemite has the most impressive and accessible granite big walls in the world. The rock is amazing. And because of that, it's been the mecca for climbing in the U.S. - and the world to a large degree - for all of climbing history. It's the place to test yourself against the historic routes of the past.
The thing with physical preparation is I have tons of friends who train at a really high level and who can give me advice. But with mental training, I don't really know anybody who has a much better mind for climbing, I guess, so I don't really know where I would go. It's not really a limiting factor for me.
I'm sponsored by the solar company Goal Zero, and they were gracious enough to install panels on my van and a nice battery system for the inside. I have lights and a fridge inside the van. And of course I had panels installed on my mom's house.
I make a fair amount of my food choices for environmental-type reasons than nutrition or taste. I'm trying to minimize impact, which is something most people don't necessarily think about when they're shopping.