text:
Mate choice, parasitism and predation
Manipulation of mate choice
Parasite-augmented mate choice as an extended phenotype
TOXOPLASMOSIS| 01 January 2013
Parasite-augmented mate choice and reduction in innate fear in rats infected by Toxoplasma gondii
Ajai Vyas
School of Biological Sciences, Nanyang Technological University
60 Nanyang Drive
avyas@ntu.edu.sg
Received: 25 Mar 2012
Accepted: 12 Jul 2012
© 2013. Published by The Company of Biologists Ltd
J Exp Biol (2013) 216 (1): 120–126.
https://doi.org/10.1242/jeb.072983
A related article has been published: HOW PERNICIOUS PARASITES TURN VICTIMS INTO ZOMBIES
Ajai Vyas; Parasite-augmented mate choice and reduction in innate fear in rats infected by Toxoplasma gondii. J Exp Biol 1 January 2013; 216 (1): 120–126. doi: https://doi.org/10.1242/jeb.072983
Typically, female rats demonstrate clear mate choice. Mate preference is driven by the evolutionary need to choose males with heritable parasite resistance and to prevent the transmission of contagious diseases during mating. Thus, females detect and avoid parasitized males. Over evolutionary time scales, parasite-free males plausibly evolve to advertise their status. This arrangement between males and females is obviously detrimental to parasites, especially for sexually transmitted parasites. Yet Toxoplasma gondii, a sexually transmitted parasite, gets around this obstacle by manipulating mate choice of uninfected females. Males infected with this parasite become more attractive to uninfected females. The ability of T. gondii to not only advantageously alter the behavior and physiology of its host but also secondarily alter the behavior of uninfected females presents a striking example of the 'extended phenotype' of parasites. Toxoplasma gondii also abolishes the innate fear response of rats to cat odor; this likely increases parasite transmission through the trophic route. It is plausible that these two manipulations are not two distinct phenotypes, but are rather part of a single pattern built around testosterone-mediated interplay between mate choice, parasitism and predation.
anti-predator behavior, behavioral manipulation, major urinary proteins, parasitism, sexual selection, sexual transmission, trophic transmission, testosterone
Parasitism is usually thought of as a relationship of exploitation. A parasite exploits its host to derive benefits of food, to obtain shelter and to gain access to a subsequent new host. Often such exploitation takes the form of behavioral manipulation, whereby the parasite alters the behavior of the infected host in order to increase its own transmission efficiency. For example, many parasites have evolved a two-host life cycle that alternates between a prey species and a predator species, taking advantage of natural predation to gain entry into new hosts. In several of these cases, the parasite changes the behavior or appearance of the infected host in ways that are likely to increase rates of predation (Moore, 2000). The ability of the parasite to alter the behavior of its host presents a striking example of the 'extended phenotype', where the genotype of the parasite manifests its phenotype outside the physical confines of its body (Dawkins, 1982).
The protozoan parasite Toxoplasma gondii has been extensively studied in the context of parasitic change in host behavior. Toxoplasma gondii undergoes a two-stage life cycle that alternates between its definitive host (felines) and intermediate hosts (almost all warm-blooded organisms, including rats). Rats retain an evolutionarily conserved innate fear of cat odors (Apfelbach et al., 2005), which is detrimental to the parasite because it relies on predation to gain entry into definitive host. Thus, T. gondii alters the behavior of infected rats by abolishing innate fear, creating instead a 'fatal attraction' (Berdoy et al., 2000). Very interestingly, the behavioral effects of T. gondii infection are fairly specific to innate fear, leaving many other related or energetically costly behaviors intact (Berdoy et al., 1995; Lamberton et al., 2008; Vyas et al., 2007a). This specificity argues that effects of infection are a specific behavioral manipulation, rather than arising from generic sickness.
Toxoplasma gondii is also transmitted sexually in sheep, dogs and rats (Arantes et al., 2009; Dass et al., 2011; de Moraes et al., 2010). For example, the parasite invades rat testes and is ejaculated along with semen, infecting females and resultant pups. In another leap of manipulative brilliance, the parasite alters mate choice in rats whereby infected males are deemed more attractive by sexually receptive females (Dass et al., 2011). This change in the behavior of uninfected females is likely to increase sexual transmission of T. gondii. But there is a bit of evolutionary depravity in these events. In general, females tend to detect and avoid males infected with an array of bacteria, protozoan, lice and nematodes (Kavaliers et al., 2006; Kavaliers et al., 2005a). The odor of parasitized males is stressful for females; for example, it initiates an analgesic response in female mice (Kavaliers and Colwell, 1992). Female avoidance of parasitized males likely reflects the cost of mating with a male of poor genetic legacy and/or risk of direct transmission of parasites (Able, 1996; Hamilton and Zuk, 1982). Toxoplasma gondii infection results in inversion of this innate aversion of females, instead instituting an attraction to parasitized males.
Thus, T. gondii-infected rats demonstrate two distinct behavioral manipulations in fear response and in mate choice. In this Review, I will first discuss the relationship between parasites, predation and mate choice. I will then discuss plausible mediators of changes in mate choice in infected rats. Subsequently, I will discuss the inter-relationship between changes in mate choice and changes in fear response.
In many species, females provide greater parental care and investment than males. This leads to a biased operational sex ratio, manifested as more sexually receptive males than females. As a direct result of such bias, males compete between themselves for access to females and females have the opportunity to choose from many suitors. This leads to sexual selection, resulting in evolution of male traits that are useful in fighting competitor males (intra-sexual selection) and influencing mate choice of females (inter-sexual selection) (Andersson, 1994; Andersson and Simmons, 2006). The intra-sexual selection often results in evolution of conspicuous male phenotypes that aim to advertise and attract females (e.g. bright plumage in birds).
From the perspective of this review, mechanisms driving mate choice in rats are of special interest. Several mechanisms have been proposed to explain preference of females for certain male traits.
It is possible that females choose males that provide a direct and immediate benefit to the female and/or their progeny (Møller and Jennions, 2001). Relevant examples include parental care or nuptial gifts (food or material tokens transferred by male during courtship or mating). Male rats provide neither parental care nor nuptial gifts. However, it is possible that female rats choose males in order to reduce the chances of direct associative transmission of parasites or diseases (Able, 1996). That will constitute a mate choice driven by direct benefit.
It is also possible that mate choice is based on indirect benefits that hinge on the greater fitness manifested by a female's offspring if she is mated with a preferred male. There are two main categories of models that have been proposed to explain indirect benefits (Andersson, 1994; Jones and Ratterman, 2009). In the first instance, preferred male traits evolve through a circular process whereby the female prefers a male trait, and she then goes on to produce male offspring with the preferred trait and female offspring with the preference of that trait. This results in a Fisherian runaway selection until the advantage of preferred traits becomes balanced by natural selection for its cost (Fisher, 1915; Hall et al., 2000). This view does not require a positive relationship between the preferred trait and male genetic quality. In the second instance, mate choice evolves because males with preferred traits produce offspring with greater viability (Andersson, 1994; Jones and Ratterman, 2009; Smith, 1991). In other words, preferred traits serve as proxies for the genetic legacy that a male can impart to the offspring. This legacy can be in the form of, among others, better defenses against parasites and/or diseases, increased ability to produce heavier muscle mass to fight competitors, or increased ability to combat oxidative stress. These 'good gene' models suffer a serious problem in that continual selection should eliminate any heritable variation in the preferred trait. Thus if female rats prefer males with a particular pheromone, males possessing that pheromone will leave more offspring and eventually all males will have the preferred pheromone. In order to reconcile this problem, it has been suggested that preferred traits are selected because they are co-related with 'good genes' that provide heritable resistance to the parasites (Endler and Lyles, 1989; Getty, 2002; Hamilton and Zuk, 1982; John, 1997; Read, 1988). Because of constant co-evolutionary cycles between host and parasite, genes for resistance never reach equilibrium, and thus can sustain continual variation and selection. It is not yet possible to ascertain whether either of these scenarios (or both simultaneously) have played a role in mate choice of rats.
Yet, it is interesting that female rodents detect and avoid males infected with a variety of parasites, including ectoparasites, protozoans, nematodes and bacteria (Ehman and Scott, 2002; Kavaliers et al., 2006; Kavaliers et al., 2005a; Kavaliers et al., 2005b; Kavaliers and Colwell, 1992; Kavaliers and Colwell, 1995; Kavaliers et al., 1998a; Kavaliers et al., 1998b; Kavaliers et al., 2003; Klein and Nelson, 1999; Willis and Poulin, 2000; Zala et al., 2008). Female rodents have evolved dedicated neural machinery that serves to detect odors emanating from infected individuals and to generate an aversive response. Thus female mate choice is influenced by the parasitic status of the male. It is difficult to hypothesize whether aversion to parasitized males evolved because of an evolutionary need of females to avoid direct associative infection or to provide for heritable resistance to the parasites.
Rat females show mate preference even when they have access to only male urine marks or soiled bedding (Dass et al., 2011; Taylor et al., 1982). The vomeronasal system is likely to be important for the determination of mate quality, in synergy with the main olfactory system (Baum and Kelliher, 2009; Tirindelli et al., 2009). This system emanates from the vomeronasal organ and contains several transmembrane receptors that bind to odorants. These receptors include members of the vomeronasal receptor family and formyl peptide receptors (reviewed in Baum and Kelliher, 2009; Tirindelli et al., 2009). The formyl peptide recptors are postulated to play an important role in the determination of diseased states (Rivière et al., 2009). Olfactory information emanating from the vomeronasal system is relayed via the accessory olfactory bulb to the medial amygdala and hypothalamic nuclei that mediate behavioral and physiological responses (Baum and Kelliher, 2009). Nonapeptide oxytocin plays an important part in recognizing pathological states during the processing of olfactory information in the medial amygdala (Kavaliers and Choleris, 2011). Hence, sexual signals in rats appear to be olfactory in nature. Rat urine contains a high amount of proteins, including major urinary proteins of the lipocalin family (Beynon et al., 2008). The major urinary proteins are testosterone dependent (Roy et al., 1987; Soares Vda et al., 1987). Thus, it can be speculated based on the available evidence that major urinary proteins serve as sexual signals in rats.
Thus, sexually selected traits might evolve in order to advertise heritable capacity to ward off parasites and/or decrease the risk of direct transmission of parasites during sexual encounters (Able, 1996; Hamilton and Zuk, 1982). At the crux of this interpretation is the idea that, in many species, sexually selected traits are expensive in terms of metabolism and opportunity, setting up a trade-off. The cost of sustaining these traits confers a form of honesty whereby only fit males can afford to display them.
Thus, the costs of sexual display are important in maintaining honesty of mate choice. What are the costs? First, sexually selected traits are, by necessity, conspicuous; they evolve to communicate and advertise. One of the collateral costs of such traits is that predators find it easier to locate conspicuous males, thus setting up a trade-off (Zuk and Kolluru, 1998). Second, expression of sexually selected traits requires testosterone in many species, including rats (Ardia et al., 2010; Bonisoli-Alquati et al., 2011; Bottoni et al., 1993; Folstad and Karter, 1992; Longpre and Katz, 2011; Roney et al., 2006; Taylor et al., 1982; Wingfield et al., 1997; Zala et al., 2008). Testosterone is a steroid produced in the testes, essential to create an immune-privileged environment for developing sperm. Over evolutionary time scales, testosterone has been co-opted to mediate a trade-off between sexually selected traits and investment in the immune system. The immune-suppressive cost of testosterone confers honesty, allowing only fit males to display the sexually selected traits. Further, in addition to its role in organizing sexual behaviors, testosterone can cross the blood–brain barrier and reduces the fear response (Aikey et al., 2002; Hermans et al., 2006; Kavaliers et al., 2001; King et al., 2005), which might further increase the predation rates on high-testosterone males.
Exploitation of sexual signals by parasites is fairly common in animals (Haynes and Yeargan, 1999; Zuk and Kolluru, 1998). Sexual signals are usually an open broadcast system, liable to reception by both the intended audience (females) and an unintended audience (parasites). Thus many parasites use host sexual signals to locate a new host. Such exploitation can lead to robust selection pressure on the host. For example, male crickets use acoustic signals to attract females. In the Hawaiian Islands, where the range of distribution of crickets overlaps with that of a parasitoid fly, the parasitoid uses the sound of calling males to locate its host and lay eggs. The developing parasitoid larva burrows into the male and consumes it from inside-out. Because calling males are disproportionately targeted by the parasitoid, natural selection has recently resulted in emergence of a novel phenotype on the island of Kauai, whereby males no longer produce calling songs but become satellites to the few remaining calling males (Zuk et al., 2006). This, along with many more examples, demonstrates that parasites are a very significant cost to host mate choice, representing a robust selection force to constraint host sexual selection. Usually this exploitation takes the form of parasites using sexual signals or mimicking sexual signals to locate their host; parasites in these cases do not manipulate mate choice directly.
The rich interplay between host sexual selection and parasites posits a very interesting and as yet under-explored possibility. From the perspective of the parasite, it is highly beneficial to successfully manipulate the mate choice of the host. For example, a sexually transmitted parasite will benefit directly if it could augment the attractiveness of the host male. This is also true for parasites that depend on close physical proximity of hosts for dispersal, for in many species the sexual encounter requires the male and female to be in close contact. Related to that, host itself benefits from infection in this situation, as parasitic manipulation enhances its odds of reproducing with more females. Relatively less obvious is the possibility that a trophically transmitted parasite might also benefit from augmented host mate choice, even if the parasite does not depend on sexual intercourse for transmission (Lafferty, 1999). More attractive infected males will increase the probability of parasite transmission, because sexually displaying males are easier to locate by predators and the testosterone that sustains the sexual display also reduces fear. Moreover, manipulation of host mate choice will result in the host recouping some of the cost of parasitism, thus blunting selection pressure from the co-evolving host. If a parasite relies on both sexual/vertical and trophic routes, the benefits of manipulation are additive. The possibility of such 'love-potion' parasitism has been discussed sporadically (Lafferty, 1999), but has not been experimentally tested. We discuss presently available experimental evidence for this phenomenon using the T. gondii rat association.
In this association, T. gondii is trophically transmitted when an infected rat is eaten by a cat. Recent evidence suggests that this parasite is also transmitted during sexual intercourse. For example, T. gondii is transferred along with the semen of infected male dogs, resulting in infection of the mated female and sired progeny (Arantes et al., 2009). Sexual transmission has also been noted in rabbits (Liu et al., 2006). Similarly, artificial insemination of sheep using semen spiked with T. gondii results in transmission of the parasite to females (de Moraes et al., 2010). Recently we have demonstrated successful transmission of the parasite from infected rats to mated females and resultant pups (Dass et al., 2011). Dual transmission routes reflect an additive advantage of manipulating host mate choice for this parasite. We tested this possibility in laboratory conditions by quantifying the preference of sexually naive females in estrus for cues of either control or infected males (Dass et al., 2011). We also compared the competitive ability of control and infected males to attract females. Uninfected females preferred parts of an arena containing urine marks deposited by infected males, compared with parts containing urine marks from control males (Dass et al., 2011). When females were allowed to choose between mating with either a control or an infected male, infected males consistently secured more intromissions and ejaculations. In the preceding experiment, a female mated in an arena housing one control and one infected male. Under non-competitive settings, i.e. where a female mated in an arena containing only one male, both control and infected males showed comparable reproductive performance. This distinction is important because it demonstrates that effects of infection were restricted to mate choice and not to the act of reproduction itself.
The role of T. gondii infection in rat mating success has been investigated previously (Berdoy et al., 1995). It was reported that infection did not alter mating success as defined by number of ejaculations and occurrences of mounting. Reproductive success of males in this arrangement is a product of both male–male competition and mate choice. One possibility is that females in this arena had less opportunity to control the timing and frequency of sexual interaction, for example by hiding in home-boxes that had an opening small enough to allow only females and not males. Several studies have established that intermittent cycles of solicitation and withdrawal by females is an essential feature of reproductive ritual in rats, and it facilitates successful pregnancy (e.g. Solomon and Keane, 2007). Another possibility is that male–male competition heavily contributed to the mating success in the semi-naturalistic setting, overriding the influence of female mate choice. This possibility will require further experimentation in the form of careful dissociation of both intra-sexual and inter-sexual behaviors. Pending that, it is difficult to ascertain whether parasitic manipulation of mate choice will result in a significant gain in reproductive fitness of infected males.
Mate choice often serves as a proxy of reproductive worth of a male because physiological conditions conducive to the production of sexual signals conflict with physiological or opportunistic demands of other life-history choices (Andersson, 1994; Andersson and Simmons, 2006). Sexual signals in many species are testosterone dependent. For example, in rats, females prefer males with greater testosterone (Taylor et al., 1982). Yet, testosterone is costly to produce and maintain (Alonso-Alvarez et al., 2009; Folstad and Karter, 1992; Wingfield et al., 1997). Firstly, the testosterone has immune-suppressive effects, leading to a trade-off on the part of males between higher testosterone and lowered capacity to fight infections. Secondly, testosterone facilitates behaviors that increase predation, leading to an opportunity cost.
In view of the centrality of testosterone to mate choice, we next asked whether T. gondii infection enhanced mate choice through enhanced testosterone. We demonstrated that T. gondii infection increased synthesis of testicular testosterone production in male rats (Lim et al., 2012). The majority of testosterone in male rats is produced by Leydig cells present in the interstitial tissue of the testes. We compared the expression of steroidogenic enzymes in these cells using quantitative PCR. The infection enhanced the expression of steroidogenic enzymes, resulting in greater production of testosterone. What is interesting about these findings is that testosterone production was enhanced through a coordinated modulation of physiological checks and balances inherent to testicular steroidogenesis. Modulation of testosterone production has been well studied in the context of its decline in aging populations (Chen et al., 2009). The synthesis of testosterone is regulated by levels of luteinizing hormone secreted from the anterior pituitary gland. This hormone binds to the luteinizing hormone receptor (LHR) in Leydig cells of the testes, driving a second messenger system that successively recruits steroidogenic machinery (Azhar and Reaven, 2007; Payne, 2007). During aging, the number of LHRs in the Leydig cells drops, without significant changes in the amount of luteinizing hormone or the number of Leydig cells (Chen et al., 2009). The decrease in LHRs results in downregulation of cholesterol transport to the mitochondria and further biochemical modification of cholesterol, all necessary for testosterone production. The effects of T. gondii infection mirrored these physiological changes, albeit in the reverse direction. The infection enhanced expression of LHR without affecting luteinizing hormone. Furthermore, enhancement of LHR in infected animals resulted in upregulation of the same enzymes that are known to be diminished in aging. This points to a coordinated organizing principle that would be difficult to bring about by mere accidental effect or pathology, and thus represents a true physiological manipulation.
The effect of T. gondii infection on testosterone has previously been studied in mice and humans. In contrast to rats, T. gondii infection in mice reduces testosterone levels (Kaňková et al., 2011). We have observed that male mice infected with the parasite do not increase their sexual attractiveness to females, unlike male rats. While female mice respond to the infection with loss of innate fear, similar to male rats (Kannan et al., 2010; Vyas et al., 2007a), evidence for behavioral change in male mice has been rather mixed in our laboratory and published studies (e.g. Xiao et al., 2012). Toxoplasma gondii is more virulent in mice, often leading to sickness behavior and mortality (Hodková et al., 2007a; Hrdá et al., 2000), while infection in rats seldom results in sickness or death. It is likely that acute stress of infection in mice suppresses gonadal function (Sapolsky, 1985). It is currently not known why T. gondii is relatively more virulent in mice compared with rats. One possibility is that current laboratory strains of the parasite co-evolved with rats and not mice. In absence of any experimental evidence, this remains a speculation. In male human volunteers, T. gondii infection is associated with a statistically non-significant increase in salivary testosterone levels (Flegr et al., 2008). In parallel, female volunteers rate portraits of infected males as being more dominant and masculine compared with uninfected males (Hodková et al., 2007b) [see review by Flegr (Flegr, 2013) for a detailed discussion of toxoplasmosis in humans].
Apart from manipulating host mate choice, T. gondii also alters host response to predator odors (Berdoy et al., 2000; Vyas et al., 2007a; Vyas et al., 2007b; Webster and McConkey, 2010). Rats infected with T. gondii loose their natural aversion to cat odor and instead develop an attraction. This behavioral change is thought to be beneficial for the parasite as it can engage in sexual recombination only in the cat intestine. Moreover, passage through the cat provides the opportunity for oocysts to be widely disseminated in the environment, potentially infective to a wide range of other warm-blooded organisms. It is pertinent to ask here whether both behavioral changes – in mate choice and innate fear – are distinct or related. Two strands of evidence support the notion that parasitic changes in mate choice and predation are instead part of a single pattern built around testosterone-mediated interplay between mate choice and predation (Fig. 1) [see reviews by Webster et al. (Webster et al., 2013) and McConkey et al. (McConkey et al., 2013) for a detailed discussion of mechanisms].
Firstly, the greater testosterone levels necessary to augment mate choice can reduce the innate fear response through collateral actions in the brain. Testosterone is believed to reduce fear in a variety of species and experimental paradigms. Administration of exogenous testosterone reduces the fear response in humans and rodents (Aikey et al., 2002; Hermans et al., 2006; Kavaliers et al., 2001), while castration potentiates the fear response to predator odors in rodents (King et al., 2005). Testosterone also imparts attractiveness to males in birds, goats, rats and humans (Ardia et al., 2010; Bonisoli-Alquati et al., 2011; Bottoni et al., 1993; Longpre and Katz, 2011; Roney et al., 2006; Taylor et al., 1982). Parts of the limbic system that regulate fear contain generous amounts of receptors that bind to either testosterone or its aromatized metabolite, estrogen (Cooke, 2006; Kostarczyk, 1986; Swann and Fiber, 1997). These regions are sexually dimorphic, suggesting that testosterone plays an organizational role in sculpting them. Moreover, these regions retain structural and molecular plasticity in adulthood in response to testosterone. For example, castration produces epigenetic changes in arginine-vasopressin in the medial amygdala, a brain region important for regulation of social behavior (Auger et al., 2011). It is possible that parasite-induced enhancement of testosterone results in long-term plastic changes within the medial amygdala, resulting in a reduced fear response. Related to this, infected animals exhibit atypical activation of the posterodorsal part of the medial amygdala, which is responsible for sexual behaviors in normal situations and is highly responsive to testosterone (House et al., 2011). Furthermore, testosterone provides negative feedback to stress hormone secretion (Viau, 2002). In turn, stress hormones play a crucial facilitatory role in generating and maintaining fear. For example, exogenous application of the stress hormone corticosterone results in plastic changes in the basolateral amygdala, resulting in excessive anxiety (Mitra and Sapolsky, 2008). Thus, testosterone could reduce fear response either directly through its action in the brain or indirectly through its suppressive effects on the stress response (Mitra et al., 2012). The main challenge for these possibilities is the fact that behavioral effects of T. gondii are rather specific (Lamberton et al., 2008; Vyas et al., 2007a; Vyas and Sapolsky, 2010). For example, although it affects innate fear, the infection does not change unconditioned anxiety or conditioned fear, although reduced anxiety has also been reported in rats (Gonzalez et al., 2007; Webster et al., 1994).
Fig.1.
Possible role of testosterone in mediating host behavioral changes after infection with Toxoplasma gondii.
Secondly, parasite-augmented mate choice could enhance predation simply because testosterone enhances sexual signaling. Sexual signals are conspicuous and thus infected animals could be eaten more readily because they are easier to catch. This possibility has not been directly tested. An indirect observation supports this speculation. Rodents use odors to communicate. If infected animals enhance their sexual signaling, and if such sexual signaling can be intercepted as kairomones by other species, it can be argued that prey species will show greater aversion to odors from infected males. Mice are readily consumed by rats, and as a result mice exhibit a robust fear response to rat odors. In agreement with greater kairomonal activity, mice exhibit greater fear of urine from infected rats when compared with controls.
Thus, in short, T. gondii infection augments the attractiveness of infected males, plausibly through its effects on testosterone (Fig. 1). Collateral effects of testosterone could also explain loss of fear in infected rats (Fig. 1). It should be noted here that precise determination of reproductive fitness for rats or the parasite has not been carried out and remains a rather difficult task. The nocturnal habits and subterranean lifestyle of rats makes them a challenging species to study in field conditions. Moreover, it is difficult to determine whether the benefits of behavioral change outweigh the cost for the parasite or whether the cost of infection outweighs the benefits for the host. The host, the parasite, the predator and the prey reciprocally affect each other, leading to a complex cascade of effects. For example, the reproductive benefit to the infected rat due to enhanced attractiveness is countered by the cost of greater predation by cats and the cost of losing prey that can smell infected rats better than non-infected rats. In the absence of greater quantitative understanding of these trade-offs, it is very difficult to confirm the adaptive significance of the parasitic manipulation of mate choice. And it is even more difficult to determine whether parasite-augmented mate choice is frequent occurrence in nature or what kind of ecological situations favor such an association. A related issue is that of individual variation (Thomas et al., 2011). Not all rats respond similarly to cat odor or to T. gondii infection. For example, although the majority of rats show robust anxiety-like behaviors in response to cat cues, some individuals remain unaffected (Mitra et al., 2009). Similarly, not all infected animals develop an attraction to cat odors (Berdoy et al., 2000; Vyas et al., 2007a). Physiological and genetic substrates mediating this individual variation remain undetermined.
Parasites change host behavior in a multitude of ways, and not all of these are behavioral manipulation by the parasite. Some of these changes are merely adaptive responses mounted by the host and some are side effects of host–parasite interactions. Poulin has proposed four criteria to recognize true manipulation (Poulin, 1995; Poulin, 2010): (1) complexity of effect; (2) purposiveness of design; (3) convergence in several lineages; and (4) increased fitness of the parasite due to manipulation (Poulin, 1995). Does parasite-augmented mate choice satisfy these criteria?
A complex behavioral change requires an organizing principle and is less likely to be an accidental effect. Male sexual signaling is expensive to create and maintain. Sexually selected traits are limited by their physiological and opportunity costs. Infected males do not increase the strength of sexual display; in fact, they become less attractive. For example, female mice avoid males infected with Eimeria vermiformis, a close relative of T. gondii, and have an aversive physiological reaction to the smell of such males (Kavaliers and Colwell, 1992; Kavaliers and Colwell, 1995). Toxoplasma gondii-infected males overcome the cost of display, producing enough upregulation in their attractiveness to affect the behavior of another individual who herself is not infected, and these naive females change not only their mate choice but their actual mating decisions. This is a complex feat that arguably supports it being a co-evolutionary change (Poulin, 1995).
Purposiveness
A behavioral manipulation is 'too well fitted' to its purpose to arrive by chance. In other words, there needs to be conformity between the observed change and 'a priori design specification that an engineer might use' (Poulin, 1995). In this regard, making infected males more attractive to females via increased testosterone production is an 'a priori design specification' – an obvious solution to increase parasite transmission through sexual intercourse. Furthermore, physiological changes in infected males follow an organized logic similar to other biological situations where testosterone production is affected, albeit in the reverse direction.
If similar effects arise in widely different lineages it is less likely that behavioral change is accidental. We are not aware of other examples where parasites augment attractiveness of infected males; the reverse is more often found. Related to this, increased circulating testosterone has also been observed in male rats infected with Seoul virus, a pathogen that is transmitted by wounding during aggressive encounters between males (Easterbrook et al., 2007). In addition, male midges infected by Unionicola ypsilophora have greater success at forming a mating pair (McLachlan, 1999), though the role of mate choice in this observation is not clear.
Fitness effects
A behavioral manipulation should lead to increased fitness of the parasite (Cézilly et al., 2010). We show that presence of behavioral manipulation leads to sexual opportunities in a competitive setting, which result in the transfer of semen containing parasites to females. These observations show that change in behavior correlates with parasite transmission. However, it must be noted that measurement of fitness is a difficult task. Moreover, fitness is often dependent on the environmental context in which experiments are conducted. The current state of research does not allow us to convincingly conclude that behavioral changes of infected rats indeed increase the fitness of the parasite.
Although not one of Poulin's criteria, the specificity of behavioral change is important. A generalized sickness behavior is considerably less interesting than a specific behavioral change, for example increasing energy demand of the infected animal to the point of lethargy, leading to its predation. The case of Toxoplasma infection is different. Infected males do not have any deficit in reproductive behavior, they do not exhibit any sickness behavior, they do not lose weight after infection, and they sire a comparable number of offspring as non-infected males when mated with a female. Infection effects in this case are very specific to mate choice of uninfected females.
Several 'good gene' models assume that male sexual signaling is an 'honest' proxy of genetic legacy. I suggest here that in some cases parasites can manipulate this supposedly honest signaling by augmenting mate choice through enhanced testosterone. I further suggest that enhanced testosterone in the infected animals plays an important role in the reduction of innate fear observed in infected rats after T. gondii infection.
This research was funded by the Nanyang Assistant Professorship program of Nanyang Technological University, Singapore, and by the Ministry of Education, Singapore.
D. J.
The contagion indicator hypothesis for parasite-mediated sexual selection
Aikey
J. L.
Nyby
J. G.
Anmuth
D. M.
P. J.
Testosterone rapidly reduces anxiety in male house mice (Mus musculus)
Horm. Behav.
Alonso-Alvarez
Pérez-Rodríguez
J. T.
Testosterone-mediated trade-offs in the old age: a new approach to the immunocompetence handicap and carotenoid-based sexual signalling
Proc. Biol. Sci.
L. W.
Sexual selection and mate choice
Apfelbach
C. D.
The effects of predator odors in mammalian prey species: a review of field and laboratory studies
Neurosci. Biobehav. Rev.
Arantes
Lopes
W. D.
Pieroni
J. S.
V. M.
Toxoplasma gondii: evidence for the transmission by semen in dogs
Exp. Parasitol.
Ardia
D. R.
Gleicher
Short-term exposure to testosterone propionate leads to rapid bill color and dominance changes in zebra finches
C. J.
Coss
Forbes-Lorman
Epigenetic control of vasopressin expression is maintained by steroid hormones in the adult male rat brain
Reaven
Regulation of Leydig cell cholesterol metabolism
Contemporary Endocrinology: The Leydig Cell in Health and Disease
Humana Press
K. R.
Complementary roles of the main and accessory olfactory systems in mammalian mate recognition
Berdoy
J. P.
D. W.
Parasite-altered behaviour: is the effect of Toxoplasma gondii on Rattus norvegicus specific?
Fatal attraction in rats infected with Toxoplasma gondii
Beynon
Turton
D. H. L.
S. D.
Cheetham
MacNicoll
Humphries
R. E.
Urinary lipocalins in Rodenta: is there a generic model?
Chemical Signals in Vertebrates
, Vol.
S. C.
Bonisoli-Alquati
Ambrosini
Rubolini
Dessì-Fulgheri
Saino
Effects of egg testosterone on female mate choice and male sexual behavior in the pheasant
R. W.
Mate choice and reproductive success in the red-legged partridge (Alectoris rufa)
Cézilly
Perrot-Minnot
Host-manipulation by parasites with complex life cycles: adaptive or not?
Trends Parasitol.
R. S.
Zirkin
B. R.
Leydig cells: from stem cells to aging
Mol. Cell. Endocrinol.
B. M.
Steroid-dependent plasticity in the medial amygdala
Vasudevan
Soh
L. J.
Sapolsky
Protozoan parasite Toxoplasma gondii manipulates mate choice in rats by enhancing attractiveness of males
The Extended Phenotype: The Long Reach of the Gene
E. P.
Faria
A. C.
V. A.
Experimental infection by Toxoplasma gondii using contaminated semen containing different doses of tachyzoites in sheep
Vet. Parasitol.
Easterbrook
J. D.
J. B.
G. E.
Pletnikov
M. V.
S. L.
Elevated testosterone and reduced 5-HIAA concentrations are associated with wounding and hantavirus infection in male Norway rats
Ehman
Female mice mate preferentially with non-parasitized males
Endler
Bright ideas about parasites
The evolution of sexual preference
Eugen. Rev.
Flegr
Influence of latent Toxoplasma infection on human personality, physiology and morphology: pros and cons of the Toxoplasma–human model in studying the manipulation hypothesis
Lindová
Kodym
Sex-dependent toxoplasmosis-associated differences in testosterone concentration in humans
Folstad
Karter
A. K.
Parasites, bright males and the immunocompetence handicap
Am. Nat.
Signaling health versus parasites
L. E.
Colasante
Toxoplasma gondii infection lower anxiety as measured in the plus-maze and social interaction tests in rats: a behavioral analysis
Behav. Brain Res.
Kirkpatrick
Runaway sexual selection when female preferences are directly selected
Heritable true fitness and bright birds: a role for parasites?
K. F.
Yeargan
K. V.
Exploitation of intraspecific communication systems: illicit signalers and receivers
Ann. Entomol. Soc. Am.
Hermans
E. J.
Putman
Koppeschaar
H. P.
van Honk
A single administration of testosterone reduces fear-potentiated startle in humans
Biol. Psychiatry
Hodková
Poorer results of mice with latent toxoplasmosis in learning tests: impaired learning processes or the novelty discrimination mechanism?
Kolbeková
Skallová
Higher perceived dominance in Toxoplasma infected men – a new evidence for role of increased level of testosterone in toxoplasmosis-associated changes in human behavior
Neuroendocrinol. Lett.
P. K.
Predator cat odors activate sexual arousal pathways in brains of Toxoplasma gondii infected rats
Hrdá
Votýpka
Transient nature of Toxoplasma gondii-induced behavioral changes in mice
J. Parasitol.
The Hamilton-Zuk theory and initial test: an examination of some parasitological criticisms
Ratterman
N. L.
Mate choice and sexual selection: what have we learned since Darwin?
Kaňková
Direct evidence of Toxoplasma-induced changes in serum testosterone in mice
Moldovan
J. C.
Yolken
R. H.
Jones-Brando
Toxoplasma gondii strain-dependent effects on mouse behaviour
Folia Parasitol.
Kavaliers
Choleris
Sociality, pathogen avoidance, and the neuropeptides oxytocin and arginine vasopressin
Psychol. Sci.
Colwell
Exposure to the scent of male mice infected with the protozoan parasite, Eimeria vermiformis, induces opioid- and nonopioid-mediated analgesia in female mice
Physiol. Behav.
Discrimination by female mice between the odours of parasitized and non-parasitized males
Analgesic responses of male mice exposed to the odors of parasitized females: effects of male sexual experience and infection status
Behav. Neurosci.
Parasitized female mice display reduced aversive responses to the odours of infected males
Brief exposure to female odors "emboldens" male mice by reducing predator-induced behavioral and hormonal responses
Muglia
Impaired discrimination of and aversion to parasitized male odors by female oxytocin knockout mice
Genes Brain Behav.
Genes, odours and the recognition of parasitized individuals by rodents
Recognition and avoidance of the odors of parasitized conspecifics and predators: differential genomic correlates
W. J.
Inadvertent social information and the avoidance of parasitized male mice: a role for oxytocin
De Oliveira
W. L.
Deficits in testosterone facilitate enhanced fear response
Psychoneuroendocrinology
Activation of the immune-endocrine system with lipopolysaccharide reduces affiliative behaviors in voles
Kostarczyk
E. M.
The amygdala and male reproductive functions: I. Anatomical and endocrine bases
Lafferty
The evolution of trophic transmission
Parasitol. Today
Lamberton
P. H.
Specificity of the Toxoplasma gondii-altered behaviour to definitive versus non-definitive host predation risk
Hari Dass
Toxoplasma gondii infection enhances testicular steriodogeneis in rat
Mol. Ecol.
doi: 10.1111/mec.12042
S. G.
Z. J.
Study on the transmission of Toxoplasma gondii by semen in rabbits
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi
Longpre
L. S.
Estrous female goats use testosterone-dependent cues to assess mates
McConkey
H. L.
Toxoplasma gondii infection and behaviour – location, location, location?
McLachlan
Parasites promote mating success: the case of a midge and a mite
Acute corticosterone treatment is sufficient to induce anxiety and amygdaloid dendritic hypertrophy
Adamec
Resilience against predator stress and dendritic morphology of amygdala neurons
Toxoplasma gondii infection induces dendritic retraction in basolateral amygdala accompanied by reduced corticosterone secretion
Dis. Model Mech.
doi:10.1242/dmm.009928
Møller
Jennions
How important are direct fitness benefits of sexual selection?
Parasites and the Behavior of Animals
Steroidogenic enzymes in Leydig cells
"Adaptive" changes in the behaviour of parasitized animals: a critical review
Parasite manipulation of host behavior: an update and frequently asked questions
Adv. Study Behav.
A. F.
Sexual selection and the role of parasites
Challet
Fluegge
Spehr
Formyl peptide receptor-like proteins are a novel family of vomeronasal chemosensors
Roney
J. R.
K. N.
Maestripieri
Reading men's faces: women's mate attractiveness judgments track men's testosterone and interest in infants
Chatterjee
Murty
C. V.
Sarkar
F. H.
Majumdar
Androgenic regulation of hepatic gene expression
J. Steroid Biochem.
Stress-induced suppression of testicular function in the wild baboon: role of glucocorticoids
Theories of sexual selection
Soares
V. C.
Gubits
Feigelson
Tissue-specific and hormonally regulated expression of a rat alpha 2u globulin gene in transgenic mice
Mol. Cell. Biol.
Reproductive strategies in female rodents
Rodent Societies: an Ecological and Evolutionary Perspective
J. O.
P. W.
Sex differences in function of a pheromonally stimulated pathway: role of steroids and the main olfactory system
Brain Res. Bull.
G. T.
Female rats prefer an area vacated by a high testosterone male
Brodeur
Maure
Franceschi
Blanchet
Intraspecific variability in host manipulation by parasites
Infect. Genet. Evol.
Tirindelli
Dibattista
Pifferi
Menini
From pheromones to behavior
Physiol. Rev.
Functional cross-talk between the hypothalamic-pituitary-gonadal and -adrenal axes
J. Neuroendocrinol.
Manipulation of host behaviour by Toxoplasma gondii: what is the minimum a proposed proximate mechanism should explain?
S. K.
Boothroyd
Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors
The effects of toxoplasma infection on rodent behavior are dependent on dose of the stimulus
Toxoplasma gondii-altered host behaviour: clues as to mechanism of action
C. F.
Effect of Toxoplasma gondii upon neophobic behaviour in wild brown rats, Rattus norvegicus
Kaushik
Toxoplasma gondii infection, from predation to schizophrenia: can animal behaviour help us understand human behaviour?
Preference of female rats for the odours of non-parasitised males: the smell of good genes?
Hillgarth
Ecological constraints and the evolution of hormone-behavior interrelationships
Brannock
Krasnova
I. N.
Sex-specific changes in gene expression and behavior induced by chronic Toxoplasma infection in mice
S. M.
Potts
W. K.
Genetic resistance to infection influences a male's sexual attractiveness and modulation of testosterone
Brain Behav. Immun.
Kolluru
G. R.
Exploitation of sexual signals by predators and parasitoids
Q. Rev. Biol.
Rotenberry
Tinghitella
Silent night: adaptive disappearance of a sexual signal in a parasitized population of field crickets
Biol. Lett.


Worthing's Pier's Southern Pavilion has recently been restored to its Art Deco glory. It feels somewhat like the lounge of a cruise liner, especially as it is laid out cabaret-style with a low-rise stage and clusters of tables and chairs for the visit of Steve Harley tonight. There are no white tuxes, but plenty of black t-shirts.
There's a mezzanine gallery around the outside of the room, where the green room resides. Steve Harley descends from that upper level, crutch in hand, via a tight-looking spiral staircase. Watching a man in his 60s who is rehabilitating from a recently-broken hip enter a gig in this manner is more nerve-racking than words can possibly describe.
But it doesn't half make for a splendid release of tension when he settles, centre stage on his necessary perch of a high stool, and launches into Ordinary People. He's flanked by long-standing Cockney Rebel honchos, Barry Wickens (violin and guitar) and James Lascelles (piano and percussion). Taking full-band songs that the audience knows and most definitely loves, they offer an improvisational take on Harley's work, using their knowledge of the material and familiarity with each other to let some elements of the performance feel like a joyous jam. It's the antithesis of Harley's recent full-band, choir and orchestra performances of Psychomodo and The Human Menagerie that will culminate in their final performances in mid-May.
Harley himself is on bristlingly rebellious form. He is as charming as the spark in his eye, as warm as the timbre of his voice, as irreverent as the edge to his stories and as abrasive as the light stubble that he sports. If he'd have started with an ironic few bars of Chumbawamba ("I get knocked down, but I get up again") you wouldn't have been surprised. He's gone on record in addressing just how much his recent injury has been a challenge, especially the need to cancel gigs for the first time in his career.
Yet it's not all banter. He talks of having put his father into a residential home and of fundraising for breast cancer charities. He talks fondly of his strong family connections in Hove, the places he would play as a child (now a Sainsbury's car park). He draws our attention to the lyrics of the now even more poignantly named Tumbling Down, and "See the Titanic sail into Brighton" to point out that it was probably in the King Alfred lido, aged three, that he contracted polio.
Very much a man finding his feet again and gaining momentum after an existential shake-up, it is a privilege to get up close and hear him being so personal. Having already made us happy, they finish with Make Me Smile. And then they have to go back up those bloody spiral stairs again.


The first year of the1980's was memorable for political drama, cable TV (which included the first 24/7 news channel), addictive video games and the movie release of Urban Cowboy. The movie would inspire a new generation of cowboy hat and boot enthusiasts that would forever change the western wear industry.
Pedro Muñoz's venture into the fashion boot industry began that same year at the height of the Urban Cowboy craze.
"I was 23 years old, studying chemistry and biology, hoping to become a veterinarian," he said. "There were two main industries in El Paso at the time – the jean business and the boot business. After Urban Cowboy came out, people wanted cowboy boots. I loved cowboy boots and thought the boot business in El Paso had great potential, so that's what I did." Stallion Boot Company was founded that year (1980) by Muñoz and his two partners, Jose Gallegos and Plutarco Rodriguez. "There were three of us, two master boot makers and me, a 23 year old, new at making boots. I had $2000, and that was borrowed," laughed Pedro.
Little did Pedro know that filling that "niche" of building a better made boot would find him and his company featured in many magazines, newspapers and publications such as the New York Times, the Art of the Boot by the late Tyler Beard and that Stallion Boot Company would be named one of the Top 25 Boot Makers in 2002.
Being a native of El Paso, Pedro is very proud of his roots and the fact the city has been named the boot capital of the world, which he and his team are an intricate part of that designation.
When you meet Pedro, his passion and enthusiasm are contagious. He oozes charisma. Standing up and designing boots with him (because he rarely sits down), you are instantly drawn into his inspiration and creativity.
My favorite place in the shop is their remarkable leather room. Pedro is a master at finding the most unique and highest quality leathers from around the world. He will even purchase skins from the crust and send it to the best tanners in Japan to have special one-of-a-kind coloring and dyes applied. Alligator, Nile crocodile and horse hides are some of his finest leathers, however you will find every legal skin in his unbelievable leather library.
Stallion is known for their impeccable finish, every centimeter of the boot is flawless. Their demand for excellence is evident when you pick them up and inspect all the incredible details.
Pedro loves to study old boots and design a modern version. "I am only the conductor. I design the boot, but our employees bring them to life. Without the right musicians, we don't make beautiful music." A Stallion Boot begins with imagination. It is then turned over to the team of expert hands, which turn a thought into a lifetime wearable work of art.
Stallion's small production shop makes a handful of high-end boots per day. Prices start at a $1000 and up. Many of the Stallion boot makers have over 40 years of experience and have brought their sons and grandsons into the boot-building business. This multi-generational trade is truly a gem in today's world.
Pedro's adventurous, free-spirit has taken him all over the world promoting and placing his footwear in countries such as Switzerland, Japan, Germany and France. His clients include Madonna, Robert Plant, Bob Dylan, Ashley Judd and Tom Cruise, to name a few.
Pedro Muñoz is now the sole owner of Stallion Boot and Belt Company, but he doesn't do it by himself; Pedro has a unique partner that knows the Stallion Boots business completely, his ex-wife Annette Lawrence. Annette had worked at Stallion off and on while raising their children. When they divorced, Annette quit Stallion and went into the restaurant business. Annette is an incredible cook/chef and a smart business woman; this paired with an incredible work ethic, made her restaurant flourish. Years later, after Pedro had hired several different office managers, he knew he needed Annette's savvy business sense back at Stallion. Annette, growing weary of the demands of owning and operating a restaurant, decided to close her restaurant and in 2012, she agreed to come back on as Vice President of the Stallion Boot Company. Annette currently oversees many aspects of the business. Their son, Alejandro, is helping his parents with the electronic side of business. He takes photos, does computer work, orders materials and helps with organization. Their daughter, Annette, helps with all the accounting, fish & wildlife permits, among other things. Another daughter, Vanessa Muñoz –Pretzell, lives in Berlin and helps with the European stores and customers. Vanessa carries a small inventory; offering iconic western boots to a European culture that loves quality.
The Muñoz children have learned different aspects of the business from both of their parents.
It has been almost 38 years since the release of Urban Cowboy; a movie that stirred the interest of a young man infatuated with boots. Now the Muñoz family employs 20 skilled boot makers that work with them, producing roughly 40 to 50 pairs of boots per week. Their goal is to create a boot-making legacy of the highest standard in craftsmanship and design in a production cowboy boot.
What's next for Stallion Boot Company? Pedro has bought land in New Mexico and has a dream to open a larger shop, hire and train more boot makers and bump his production up to a max capacity of 200 pair per week. His love and passion for boots has only grown over the years, and one thing is for sure, if you ever pull on a pair of remarkable Stallion Boots – you too will get the boot bug. Beware: they come with an addiction warning!


he effort to give voters a say in whether red light cameras are used in their community is spreading across Texas. Already, voters in College Station, Baytown, Houston and Dayton have rejected the use of automated ticketing machines. Yesterday the city council in League City voted to put the issue on the November ballot, and voters in Port Lavaca turned in sufficient signatures last week to force an election.
Red light camera vendor American Traffic Solutions (ATS) is furious that police in Kansas City, Missouri released a report last week evaluating photo enforcement intersections without giving the company a chance to modify the data. In many cities, ATS plays a key role in authoring such studies, but in this case the Kansas City police department went its own way, arriving at conclusions consistent with other, independent research on the topic.
Lightning destroyed a Australian speed camera and a shotgun destroyed Italian photo radar.
The South Carolina legislature put the final nail in the coffin of photo enforcement earlier this month. Both the state House and Senate last year had unanimously approved legislation making it clear that automated ticketing machines were illegal in the state. As part of a compromise, state Senator Tom Davis (R-Beaufort) dropped his opposition to the bill in exchange for the creation of the South Carolina Traffic Enforcement Commission, which he hoped would draft a report he could use to convince his colleagues to give photo ticketing a second chance.
The Insurance Institute for Highway Safety (IIHS) grabbed headlines last February with a self-published study claiming installation of red light cameras nationwide would have prevented 815 deaths. The Florida Public Health Review, a peer-reviewed journal, published a systematic critique yesterday that found the methods used in the IIHS report were sloppy and inconsistent, reflecting a bias towards the insurance industry that IIHS serves.


text:
package org.jetbrains.plugins.scala
package lang
package psi
package impl
package expr

import com.intellij.lang.ASTNode
import com.intellij.psi.{PsiElementVisitor, PsiField, ResolveState}
import org.jetbrains.plugins.scala.lang.psi.api.ScalaElementVisitor
import org.jetbrains.plugins.scala.lang.psi.api.expr._
import org.jetbrains.plugins.scala.lang.psi.api.statements.params.ScClassParameter
import org.jetbrains.plugins.scala.lang.psi.api.statements.{ScFunction, ScVariable}
import org.jetbrains.plugins.scala.lang.psi.types.Compatibility.Expression
import org.jetbrains.plugins.scala.lang.psi.types.Unit
import org.jetbrains.plugins.scala.lang.psi.types.result.{Success, TypingContext}
import org.jetbrains.plugins.scala.lang.resolve.processor.MethodResolveProcessor
import org.jetbrains.plugins.scala.lang.resolve.{ScalaResolveResult, StdKinds}

/**
 * @author Alexander Podkhalyuzin
 */

class ScAssignStmtImpl(node: ASTNode) extends ScalaPsiElementImpl(node) with ScAssignStmt {
  override def toString: String = "AssignStatement"

  protected override def innerType(ctx: TypingContext) = {
    getLExpression match {
      case call: ScMethodCall => call.getType(ctx)
      case _ =>
        resolveAssignment match {
          case Some(resolveResult) =>
            mirrorMethodCall match {
              case Some(call) => call.getType(TypingContext.empty)
              case None => Success(Unit, Some(this))
            }
          case _ => Success(Unit, Some(this))
        }
    }
  }

  override def accept(visitor: PsiElementVisitor) {
    visitor match {
      case visitor: ScalaElementVisitor => super.accept(visitor)
      case _ => super.accept(visitor)
    }
  }

  @volatile
  private var assignment: Option[ScalaResolveResult] = null

  @volatile
  private var assignmentModCount: Long = 0L

  def resolveAssignment: Option[ScalaResolveResult] = {
    val count = getManager.getModificationTracker.getModificationCount
    var res = assignment
    if (res != null && count == assignmentModCount) return assignment
    res = resolveAssignmentInner(shapeResolve = false)
    assignmentModCount = count
    assignment = res
    res
  }

  @volatile
  private var shapeAssignment: Option[ScalaResolveResult] = null

  @volatile
  private var shapeAssignmentModCount: Long = 0L

  def shapeResolveAssignment: Option[ScalaResolveResult] = {
    val count = getManager.getModificationTracker.getModificationCount
    var res = shapeAssignment
    if (res != null && count == shapeAssignmentModCount) return shapeAssignment
    res = resolveAssignmentInner(shapeResolve = true)
    shapeAssignmentModCount = count
    shapeAssignment = res
    res
  }

  @volatile
  private var methodCall: Option[ScMethodCall] = null

  @volatile
  private var methodCallModCount: Long = 0L

  def mirrorMethodCall: Option[ScMethodCall] = {
    def impl(): Option[ScMethodCall] = {
      getLExpression match {
        case ref: ScReferenceExpression =>
          val text = s"${ref.refName}_=(${getRExpression.map(_.getText).getOrElse("")})"
          val mirrorExpr = ScalaPsiElementFactory.createExpressionWithContextFromText(text, getContext, this)
          mirrorExpr match {
            case call: ScMethodCall =>
              call.getInvokedExpr.asInstanceOf[ScReferenceExpression].setupResolveFunctions(
                () => resolveAssignment.toArray, () => shapeResolveAssignment.toArray
              )
              Some(call)
            case _ => None
          }
        case methodCall: ScMethodCall =>
          val invokedExpr = methodCall.getInvokedExpr
          val text = s"${invokedExpr.getText}.update(${methodCall.args.exprs.map(_.getText).mkString(",")}," +
            s" ${getRExpression.map(_.getText).getOrElse("")}"
          val mirrorExpr = ScalaPsiElementFactory.createExpressionWithContextFromText(text, getContext, this)
          //todo: improve performance: do not re-evaluate resolve to "update" method
          mirrorExpr match {
            case call: ScMethodCall => Some(call)
            case _ => None
          }
        case _ => None
      }
    }

    val count = getManager.getModificationTracker.getModificationCount
    var res = methodCall
    if (res != null && count == methodCallModCount) return methodCall
    res = impl()
    methodCallModCount = count
    methodCall = res
    res
  }

  private def resolveAssignmentInner(shapeResolve: Boolean): Option[ScalaResolveResult] = {
    getLExpression match {
      case ref: ScReferenceExpression =>
        ref.bind() match {
          case Some(r: ScalaResolveResult) =>
            ScalaPsiUtil.nameContext(r.element) match {
              case v: ScVariable => None
              case c: ScClassParameter if c.isVar => None
              case f: PsiField => None
              case fun: ScFunction if ScalaPsiUtil.isViableForAssignmentFunction(fun) =>
                val processor = new MethodResolveProcessor(ref, fun.name + "_=",
                  getRExpression.map(expr => List(Seq(new Expression(expr)))).getOrElse(Nil), Nil, ref.getPrevTypeInfoParams,
                  isShapeResolve = shapeResolve, kinds = StdKinds.methodsOnly)
                r.fromType match {
                  case Some(tp) => processor.processType(tp, ref)
                  case None =>
                    fun.getContext match {
                      case d: ScDeclarationSequenceHolder =>
                        d.processDeclarations(processor, ResolveState.initial(), fun, ref)
                      case _ =>
                    }
                }
                val candidates = processor.candidatesS
                if (candidates.size == 1) Some(candidates.toArray.apply(0))
                else None
              case _ => None
            }
          case _ => None
        }
      case _ => None
    }
  }
}

redpajama_set_name: RedPajamaGithub


The iPad is a great device to record and document your family's special events. So, when you take it with you to the San Jose Children's Discovery Museum to capture your child's day experiencing the interactive exhibits, you are one of many parents with an iPad in hand.
Ifixers ifixers repareert smartphones binnen het uur. Kom langs in 1 van onze filialen of kies de pick-up service. Iphone 4 Glass Replacement If you're looking for a Galaxy S9 or an iPhone X lookalike with the notch … The display, a 5.2-inch Full HD model, is protected by the latest Corning Gorilla Glass 5 technology.
With more than 100,000 iPhone and iPad fixed, we are the best in the San Francisco San Jose Bay Area. Get your iPad in perfect working order with a quick turnaround time.
iPad Screen Repair San Jose, California. One of the most frequent repairs is a cracked screen. To get your iPad back in your hands quickly and running smoothly, CPR offers screen repairs that are high quality, affordable, and timely.


text:
Trump travel ban extension raises concern
Posted on Feb 6, 2020 by Viggo Stacey
Posted in News, under North America.
Tagged with NAFSA, Nigeria, travel ban, US.
US president Donald Trump has added six more countries to his administration's visa and travel ban – including Africa's largest economy, Nigeria – to the dismay of international education professionals in the US.
The Trump administration claims the security and travel proclamations have "immeasurably improved" national security. Photo: wikimedia
About Viggo Stacey
Viggo has previously worked in teaching in Germany and Turkey, until his change of career in 2017. Known as 'Sitting-Vig' to his friends, in his free time he is normally watching a film as he attempts to watch more films than anyone else. Get in touch with Viggo on viggo@thepienews.com.
Members of the country's international education sector are concerned it will mar the USA's reputation
Citizens from Myanmar, Eritrea, Kyrgyzstan, and Nigeria will no longer be issued immigrant visa, while "certain nationals" of Sudan and Tanzania will be unable to participate in the 'Visa Lottery'.
"As international educators…we are deeply disturbed by this latest travel ban expansion"
Although the extension of the ban will reportedly not restrict international students from entering the US, members of the country's international education sector are concerned it will mar the USA's reputation.
"As international educators committed to fostering a peaceful, more welcoming US, we are deeply disturbed by this latest travel ban expansion and the message it sends: that the US is not a place that welcomes or respects people of diverse backgrounds and perspectives," said NAFSA's executive director and CEO, Esther D. Brimmer.
The latest iteration of the ban will "undoubtedly accelerate the alarming decline of international students in the US", she added.
The Trump administration claims the security and travel proclamations have "immeasurably improved" national security and "dramatically strengthened" the integrity of the US immigration system.
The number of international students in the US has shrunk by more than 10% over the last three years, Brimmer continued.
"Policies like these and the unwelcoming rhetoric from some of our nation's leaders continue to hinder our ability to succeed in today's global competition for talent," she said.
According to NAFSA, more than 17,000 international students and scholars from the six countries generated around US$619 million in economic activity in 2019.
"While some may claim that by preventing legitimate travel from these countries is a necessary precaution… foreign policy leaders for decades have agreed that true security lies in understanding the nature of specific threats and focusing on individuals who mean to cause us harm—not in preventing entire nationalities from entering the US," Brimmer added.
Speaking with The PIE News, professor of Educational Policy Studies & Practice at the University of Arizona, Jenny Lee, warned that the extended travel ban is "an extended Muslim ban as well as the beginnings of an African ban".
The effect would be a narrowing of diversity on US campuses, she added.
"International students from these countries may continue to enter the US, but they are nevertheless directly impacted by the expanded travel ban," Lee noted.
"The effect would be a narrowing of diversity on US campuses"
"International graduate students especially travel with their families and oftentimes with intentions to stay and apply their advanced degrees. These individuals contribute greatly as an integral part of the US' highly skilled workforce."
A "sweeping ban" based on nationality sends a xenophobic message that students are not welcome in the US, Lee added.
"Students from other countries, particularly from these same regions, may also feel uncertain about their future prospects in the US. It is doubtful that this is the last travel ban to come," she said.

redpajama_set_name: RedPajamaCommonCrawl


text:
Der Gelbspötter (Hippolais icterina) ist ein Singvogel aus der Familie der Rohrsängerartigen (Acrocephalidae). Dieser Spötter besiedelt Teile der westlichen und zentralen Paläarktis vom Nordosten Frankreichs, der Schweiz und dem Südwesten Skandinaviens nach Osten bis in das nordwestliche Vorland des Altai. Der Gelbspötter bewohnt ein breites Spektrum von Habitaten mit lockerem Baumbestand und höherem Gebüsch, in Mitteleuropa unter anderem Auwälder und feuchte Laubmischwälder, aber auch Feldgehölze, Friedhöfe und naturnahe Parkanlagen. Die Art ist Langstreckenzieher und überwintert im tropischen Zentral- und Südafrika.

Der Bestand gilt vor allem im Westen des Areals in Mitteleuropa als leicht rückläufig, als eine der Ursachen wird dort Konkurrenz mit dem zunehmenden und sich ausbreitenden Orpheusspötter vermutet. Weltweit wird der Gelbspötter von der IUCN aber aufgrund des großen Verbreitungsgebietes und des sehr hohen Gesamtbestandes als ungefährdet ("least concern") eingestuft.

Beschreibung
Gelbspötter sind recht kleine, schlanke Singvögel mit eher großem Kopf, recht kräftigem Schnabel, langen Flügeln und relativ kurzem Schwanz. Sie sind verglichen mit anderen Spöttern recht auffallend gefärbt mit einer im frischen Gefieder bräunlich olivgrünen Ober- und einer hellgelben Unterseite, zeigen aber ansonsten wie alle Spötter keine auffallenden Zeichnungen. Die Geschlechter unterscheiden sich bezüglich Größe und Färbung nicht.

Mit einer Körperlänge von 12,0 bis 13,5 cm und einem Gewicht von 11 bis 19 g ist die Art deutlich kleiner als ein Haussperling und nur etwa halb so schwer. Bei adulten Vögeln ist die gesamte Oberseite des Rumpfes sowie Hals und Kopf einfarbig bräunlich olivgrün. Die Zügelregion, der kurze Überaugenstreif sowie die Augenumgebung sind blassgelb. Die mittleren Armdecken sind dunkelbraun, die großen Armdecken olivbraun. Die Schwingen sind schwärzlich braun, die Handschwingen und die Schirmfedern zeigen schmale, die Armschwingen breitere gelbliche Säume an den Außenfahnen und gelbliche Spitzen. Die Steuerfedern sind dunkelbraun und sehr schmal heller braun gerandet. Die gesamte Rumpfunterseite, die Unterflügeldecken sowie die Unterschwanzdecken sind hell gelb, wobei die intensivere Gelbfärbung oft auf Kehle und Vorderbrust beschränkt ist. Brustseiten und Flanken zeigen einen bräunlichen Anflug.

Die Iris ist dunkelbraun. Der Schnabel ist deutlich zweifarbig; der Oberschnabel ist dunkelbraun, der gesamte Unterschnabel gelblich. Die Beine sind bleigrau.

Im Jugendkleid ist die Oberseite mehr braungrau und weniger oliv, die Unterseite blasser gelb mit ausgedehnter braunen Flanken. Schwingen, Steuerfedern und die Deckfedern der Oberseite sind warm bräunlich gerandet.

Die innerartliche Variation ist sehr gering und es werden keine Unterarten anerkannt.

Verwechslungsmöglichkeiten
Der im westlichen Europa und westlichen Mittelmeergebiet einschließlich Italien vorkommende Orpheusspötter ist dem Gelbspötter sehr ähnlich. Die Verbreitungsgebiete dieser Arten überschneiden sich im nordwestlichen Frankreich, in Belgien, in den Niederlanden und auch zunehmend im südwestlichen Deutschland. Der Flügel des Gelbspötters, genauer gesagt die Federn der Handschwingen, sind jedoch länger. Mit etwas Erfahrung kann man an sitzenden Tieren die längere sogenannte "Handschwingenprojektion" erkennen. Die Schirmfedern des Gelbspötters sind außerdem hell gerandet und bilden beim sitzenden Vogel ein aufgehelltes Feld auf dem Flügel, das beim Orpheusspötter fehlt. In Gebieten wo beide Arten vorkommen besiedelt der Orpheusspötter eher Buschvegetation in offenen Landschaften, ein Biotop das für Gelbspötter ungewöhnlich ist.
Alle anderen Spötterarten Europas haben keine grün-gelbe, sondern eine grau-weiße oder braune-weiße Färbung.

Für vogelkundliche Anfänger ähnelt der Gelbspötter auch verschiedenen Laubsängern, wie Fitis und Zilpzalp. Laubsänger sind jedoch kleiner und gedrungener, ihr Schnabel deutlich dünner und kürzer.

Lautäußerungen

Der laute, schnelle und am Anfang der Brutzeit häufig lang anhaltende Gesang wird von den Männchen im Revier von einer Warte vorgetragen, die sich meist gut gedeckt im Laub von Büschen oder Bäumen befindet. Er enthält zahlreiche kurze Imitationen anderer Vogelgesänge oder -rufe. Charakteristisch werden dazwischen immer wieder kurze, nasale oder jammernde, mehrfach wiederholte Laute wie "GÍe-GÍe" oder "hiäh" sowie melodische, lange Pfeiftöne eingeflochten. Der Lockruf am Brutplatz ist ein melodisches, dreisilbiges "tä-tä-LÜÜit", die Warnrufe sind scharf wie "täck" oder gereiht "tä tä tä …".

Verbreitung

Der Gelbspötter besiedelt Teile der westlichen und zentralen Paläarktis von der borealen bis in die gemäßigte Zone. In Ost-West-Richtung reicht die Verbreitung vom Nordosten Frankreichs und der Schweiz bis in das nordwestliche Vorland des Altai. Die Nordgrenze der geschlossenen Verbreitung verläuft von Südskandinavien, etwa 62° N in Südfinnland und etwa 61°30 N an der Petschora, bis Tomsk in Westsibirien; die Südgrenze vom Nordrand der Alpen über den Norden der Balkanhalbinsel bis in den Nordosten Bulgariens und dann entlang der Ost- und Nordküste des Schwarzen Meeres über die Krim, bis in den Bereich südöstlich des Asowschen Meeres und dann bei etwa 52° N an Ural und Wolga und etwa 52–54° N in Kasachstan bis zum Nordrand des Altai.

Lebensraum
Der Gelbspötter bewohnt ein breites Spektrum von Habitaten mit lockerem Baumbestand und höherem Gebüsch, bevorzugt mehrschichtige Laubgehölze mit einem geringen Deckungsgrad der Oberschicht. In Mitteleuropa besiedelt die Art unter anderem Auwälder und feuchte Laubmischwälder, aber auch Feldgehölze, Hecken, Friedhöfe und naturnahe Parkanlagen.

Ernährung
Die Nahrung besteht in Mitteleuropa zur Brutzeit in erster Linie aus Insekten, seltener aus Webspinnen und selten aus kleinen Schnecken. Früchte werden offenbar nur ausnahmsweise verzehrt. Bei einer Untersuchung der Nestlingsnahrung von vier Brutpaaren in Burgund waren 87,4 % der Nahrungstiere Insekten, 9 % Spinnentiere, 3,2 % Schnecken und 0,45 % Schnurfüßer (Julidae). Unter den Insekten dominierten Fliegen mit 22,5 %, danach folgten Blattläuse mit 16,3 %, Mücken mit 14,1 % und Käfer mit 12,3 %.

Die Nahrungssuche erfolgt in allen Schichten der Vegetation, aber überwiegend in Höhen zwischen 2 und 8 Metern. In den Baumkronen jagen Gelbspötter vor allem im äußeren Bereich. Beute wird meist im Flug, im Sitzen oder hüpfend von der Vegetation abgelesen, weniger häufig fliegend erbeutet und nur selten vom Ansitz aus in der Luft gefangen.

Fortpflanzung

Gelbspötter führen eine monogame Brut- oder Saisonehe. Das Nest wird in Bäumen und Sträuchern jeder Art im Zentrum oder im Randbereich der dichten Zweige und Blätter gebaut. Es wird meist auf einem Ast errichtet und dann durch feine Zweige gestützt, die in die Nestwandung eingeflochten werden, oder in einem kleinen Astquirl aufgehängt. Die Nester werden in Mitteleuropa meist in 1 bis 4 m Höhe errichtet, selten höher oder auf dem Boden in dichter Vegetation.
Das ordentliche, napfförmige und außen wie innen glattwandige Nest wird vorwiegend vom Weibchen meist aus Halmen und anderem feinen pflanzlichen Material gebaut, häufig werden auch Wollfäden, Papierstückchen und Ähnliches verbaut. Im äußeren Wandbereich können auch gröbere Materialien wie Rindenstücke, teilweise zersetzte Laubblätter oder grobe Haare verwendet werden. Die Nestwände werden durch außen aufgebrachte klebende oder elastische Stoffe wie Spinnweben, Kokons, Wollhaare und Ähnliches verfestigt. Zur Auskleidung der eigentlichen Nestmulde werden feine Pflanzenfasern, Tierhaare oder Federn verwendet. Die Nester haben einen Außendurchmesser von 60 bis 90 mm und eine Höhe von 50 bis 120 mm.

Die Eiablage erfolgt je nach geografischer Lage variabel, in Mitteleuropa ausnahmsweise bereits um den 30. April, meist ab Mitte Mai und mit einem Höhepunkt Ende Mai bis Mitte Juni. Letzte Gelege werden Ende Juli begonnen. Zweitbruten kommen in Mitteleuropa wohl nur sehr selten vor. Das Gelege besteht aus 3 bis 7, meist 4 bis 5 Eiern, die auf heller oder dunkler rosarotem Grund locker schwarz oder dunkelbraun gepunktet sind. Die Brutzeit dauert 12 bis 14 Tage, die Bebrütung erfolgt ausschließlich durch das Weibchen. Beide Eltern füttern. Die Jungvögel verlassen mit 13,5 bis 15,5 Tagen das Nest und werden danach noch 8 bis 11 Tage lang von den Eltern geführt und mit Nahrung versorgt. Die Geschlechtsreife wird am Ende des ersten Lebensjahres erreicht.

Wanderungen
Die Art ist Langstreckenzieher. Der Wegzug mittel- und nordeuropäischer Vögel erfolgt Ende Juli bis Mitte September mit einem Höhepunkt Anfang August. Feststellungen im Oktober sind in Mitteleuropa bereits sehr selten. Die Weltpopulation des Gelbspötters überwintert im tropischen zentralen und südlichen Afrika südlich der Sahara unter Aussparung der Wüsten und des tropischen Regenwaldes. Das Winterquartier reicht vom Südosten der Demokratischen Republik Kongo nach Osten bis Ruanda und Tansania, nach Süden über Malawi und Sambia bis Namibia, Botswana und Transvaal. Die Art überwintert überwiegend in der Dornsavanne und in Akazienwäldern. Die ersten Heimzieher werden in Mitteleuropa ausnahmsweise schon Anfang oder Mitte April, im Normalfall aber erst Anfang bis Mitte Mai beobachtet. Der Heimzug erreicht im Mai seinen Höhepunkt und läuft Mitte Juni aus.

Bestand
Gesicherte Angaben zum Weltbestand gibt es nicht, BirdLife International gibt als grobe Schätzung 10 bis 30 Mio. Individuen an.

Quellen

Literatur
 Urs N. Glutz von Blotzheim, Kurt M. Bauer: Handbuch der Vögel Mitteleuropas. Band 12/I: Passeriformes. 3. Teil: Sylviidae. Aula, Wiesbaden 1991, ISBN 3-89104-021-0, S. 568–601.

Einzelnachweise

Weblinks

Sonstige Weblinks

 Federn des Gelbspötters

Rohrsängerartige

redpajama_set_name: RedPajamaWikipedia


Why SelClene Herts & Bucks?
This time of year our floors can take a real battering with the family and pets traipsing through. Here are some top tips for cleaning all different types of flooring.
Lino can be quite difficult to clean and dirt can become ingrained in it. Lino is made up of linseed oil, resin, limestone, wood fibre and cork, which are all natural products.
Mix up a solution of washing up liquid and water, spray the lino in sections then wipe with a micro fibre cloth.
Laminate flooring is very popular but difficult to maintain the appearance. If water goes under the flooring this can start to ruin the look.
Vacuum the laminate, picking up loose debris, then using a dry mop, clean the surface. To remove muddy marks use a damp cloth on the area, this will ensure no water goes under the flooring.
Hardwood is very hygienic and easy to clean as the surface has been sealed.
Gently vacuum the surface, by hoovering on a lower setting this will ensure the surface isn't scratched.
Mop using a mild detergent and a damp mop, try not to use too much water as this will remain on the surface and need to cleared using a cloth.
Stone flooring either needs a specialist cleaner or just diluted washing up liquid. Using a product with too much acid in will damage the stone.
First vacuum the area then mop, again do not saturate the stones.
SelClene Herts & Bucks is a domestic cleaning company who provide cleaners within the local area.
All our cleaners are fully vetted and covered by our insurance.
This entry was posted in Cleaner Updates, Client Updates on January 30, 2018 by Tracey Clee.
Spring clean your appliances make them feel like new again!
Its easy to forget these appliances when doing a spring clean of your property, so make them feel loved again by showing them some attention.
To ensure they are working properly take some time to give them a thorough clean, you know you would be lost without them!
Remove the soap drawer, this always needs maintaining, give it a thorough wash and then wipe over with white vinegar this will remove any bacteria.
The next thing is to tackle the rubber edging that runs around the drum, quite often this is where fluff and mould collect, clean the rubber edging thoroughly and then wipe over with white vinegar.
To disinfect the drum set your washing machine to a high temperature and then add a cup of white vinegar.
The filter is a trickier job, this can become clogged with anything. Make sure you have plenty of towels and a bowl as water will come out of the filter area when the filter is removed. Give the filter a good clean and replace.
The edges of the machine are usually missed, so using a damp cloth wipe these over and then wipe again with white vinegar.
I'm sure you always do remove debris from the drain, but check to see before taking this out and running it under hot water to remove anything left in it, then replace it.
The spinning arms have water holes which can sometimes not work properly as food items maybe blocking them, the ideal item to unblock these is a tooth pick, once this has been carried out rinse with warm water.
The detergent and rinse aid compartment needs a wipe over. Replace or top up your machine with salt and rinse aid and your good to go!
For all your domestic cleaning requirements call SelClene St Albans Ltd on 01727 828875, we offer weekly cleaning and one off cleans at a very competitive rate!
This entry was posted in Cleaner Updates, Client Updates on January 26, 2018 by Tracey Clee.


Q1- Describe briefly the Travelling Salesman Problem.
Q2- Genetic Algorithm brief introduction.
taking screen shots of your program.
Q5- Provide the references that you refer in your assignment as well as the source code.
يبدو أن هذه وظيفة جامعية أو ما شابه، وهذا المكان ليس لحل الوظائف بل لمساعدتك إن واجهتك مشكلة بينما تحاولين حلها.


text:
Miejscowości w Polsce
 Bednarze – wieś w woj. łódzkim, w pow. bełchatowskim, w gminie Szczerców
 Bednarze – wieś w woj. mazowieckim, w pow. węgrowskim, w gminie Korytnica
 Bednarze – część wsi Rybna w województwie małopolskim, w powiecie krakowskim, w gminie Czernichów


text:
NNAF selects publisher of The Atlanta Voice for board of directors
The National Newspaper Association Foundation (NNAF) announced Janis L. Ware, publisher of The Atlanta Voice to its board of directors. As a member of the board, Ware will serve a one year term which began October 2021. "It is an honor to be included on this board of respected newspapers throughout the country," Ware said. "While I have always believed […]The National Newspaper Association Foundation (NNAF) announced Janis L. Ware, publisher of The Atlanta Voice to its board of directors. As a member of the board, Ware will serve a one year term which began October 2021. "It is an honor to be included on this board of respected newspapers throughout the country," Ware said. "While I have always believed […]Read MoreFeedzy
Martel Sharpe
PrevPreviousArchitecture Firm Brings 'Diversity and Sensitivity' to Local Communities
NextArchitecture Firm Brings 'Diversity and Sensitivity' to Local CommunitiesNext


Figure 4 shows a third example of the use of KOH-eluent generation in HPAEC-PAD. Patil and Rohrer used a 4-µm-version of the Dionex Carbopac PA20 to optimize the separation of glycoprotein monosaccharides and amino sugars in HCl and TFA hydrolysates. The smaller particle size of this column offers higher peak efficiencies, leading to high-resolution separations and allowing a shorter column format and, ultimately, significantly shorter run times. It results in baseline-resolved peaks that elute within six minutes off the column. The total run time of 20 minutes allows for washing and re-equilibration after the column regeneration step. The chromatogram shows not only the region where the monosaccharides and amino sugars elute but also the column wash and re-equilibration .
Aggrawal and Rohrer demonstrated the use of RFIC for HPAEC-PAD for the analysis of mono- to oligosaccharides in honey. Using a Dionex Carbopac PA210-4µm to separate low concentrations of carbohydrates in the presence of high concentrations of glucose and fructose, this method enabled the detection of honey-adulteration by the addition of industrial sugar syrups .
In all the above-demonstrated cases the user-independent inline and high-pressure electrolytic eluent generation of KOH-eluents, both isocratic and gradient, provides accurate eluent concentrations and precise retention times, which are prerequisites for reproducible and reliable analytical data.
The elution of oligo- and polysaccharides requires the use of a "pushing ion", like acetate or nitrate [5,20]. The "pusher" accelerates the elution of strongly bound species without compromising selectivity or interfering with the pulsed amperometric detection. Until recently applications requiring such eluent compositions had to be performed using manually prepared eluents. With the Dual Eluent Generation Cartridge (Dual EGC) mode of operation (Figure 5, online), electrolytically generated eluents become available for the analysis of complex carbohydrates. In this new mode, RFIC systems employ a methanesulfonic acid (MSA) and EGC KOH cartridge, in series, to electrolytically generate KOH/potassium methanesulfonate (KMSA) eluents. This operating mode is applicable with capillary (0.4 mm) and analytical column formats (1.0 mm). Huang et al. demonstrated its use for profiling galactosyl-oligosaccharides (GOS)  and the analysis of N-linked oligosaccharides from glycoproteins , with a Dionex Carbopac PA200 column set in the 1 mm format. As a representative example for the elution for even stronger retained polysaccharides, Figure 6 (online) shows an inulin-separation in the dual EGC operation mode.
Applying electrolytic eluent generation to HPAEC-PAD improves the consistency of producing low KOH-concentration eluents and KOH gradients for the elution of smaller saccharides. In addition, the method is shown to be user-independent, reproducible and robust in terms of retention time and peak area precision.
The Dual EGC mode enables an analyst to run gradient methods using electrolytically generated KOH/KMSA to elute stronger retained oligo- and polysaccharides. This offers greater reproducibility, eliminates manual preparation of eluents, and maximizes instrument uptime. The Dual EGC mode shows excellent performance for HPAEC-PAD of complex carbohydrates. In its different modes of operation, RFIC improves the reproducibility of HPAEC-IPAD analyses and ensures greater accuracy and comparability between instruments as well as laboratories.


text:
Gold can be whatever you want it to be — which is why you should treat it with caution
Tom Bradley ([email protected])
Published: Nov 20, 2020 at 7 a.m.
Updated: Nov 20, 2020 at 12:50 p.m.
Gold is back in vogue. The price has risen from US$1,200 two years ago to US$1,900 today. Gold ETFs have grown rapidly, and gold miners have rivalled tech giants for stock market leadership.
I think of gold as a chameleon. It fits Merriam-Webster's definition perfectly — "a person who often changes his or her beliefs or behavior in order to please others or to succeed." It can be whatever you want it to be. For people who are passionate about gold, there's always a reason to own it.
Consider the many and varied roles gold plays in portfolios.
Inflation hedge: Gold is bought as insurance against rising inflation. This feature hasn't been tested in a long time, but as accommodative monetary policy continues unabated and liquidity abounds, inflation is back in the conversation.
Safe haven: Gold is perceived to be a store of value in times of financial crisis. The CEO of Barrick Gold, Mark Bristow, told the Financial Times recently, "The deep structural damage to the global economy and society at large (from COVID-19) will be with us for a lot longer, it will be like the Second World War crisis.… The peak (in gold) will be higher than we've seen."
Why investors should spend less time trying to avoid the dips and more time preparing for them
When it comes to investing, don't believe everything you see on TV
If stock valuations seem out of whack, blame the slow burn of a declining discount rate
Currency: Some investors consider gold to be an alternative to the conventional 'fiat' currencies, which can be issued in unlimited quantities and aren't backed by a commodity. Gold doesn't offer a yield, but the opportunity cost of holding it is now minimal given that T-bill yields in the major currencies are near zero.
Hedge against a weak USD : On the currency theme, gold is considered a good place to hide when the U.S. dollar, the world's reserve currency, is weakening. This feature is of less interest to Canadian investors, however, because our loonie tends to appreciate in these circumstances.
Cyclical play : According to the World Gold Council, an industry sponsored organization, jewellery and technology make up 42 per cent of annual gold demand. Earlier in my career, analysts talked a lot about the supply and demand, and even casual observers like me knew where mine production was headed and how strong jewellery demand was. Today, this work has been pushed into the shadows by the other 58 per cent of demand.
Sentiment play: I'm referring here to the gold being bought by investors — Central Banks and ETFs. The expansion (or shrinkage) of reserves and ETFs is now a more important influence on the gold price, which makes it a useful tool for assessing where investors are on the fear-vs.-greed spectrum.
Diversifier: The holy grail for investment managers is finding an asset class or strategy that provides a reasonable return and is not correlated to the stock market, which is the biggest single risk factor in most portfolios. Gold fits the bill. It tends to rise when fear is greatest.
Value stocks: Valuations on gold companies are highly dependent on the gold price assumption, which in turn is heavily influenced by the tone of the market. For decades, gold stocks traded at large premiums to their net asset values (NAV), but the higher price for bullion has narrowed the gap. Companies can now be assessed on their ability to generate cash flow and pay dividends although they're still trading at a premium to NAV and as one analyst put it, "they're not screamingly cheap."
A big plus for high-quality gold stocks is their scarcity value. There aren't many of them.
Heads I win, tails you lose
In the buildup to the U.S. election, Randy Smallwood, chief executive of Wheaton Precious Metals Corp., told the Post that, "any election outcome could trigger gold prices."
Juan Carlos Artigas, the head of research at the World Gold Council, takes this "heads I win, tails you lose" notion a step further, pointing out that consumer demand is positively linked to the economic cycle while investment flows are countercyclical. Therefore, "gold remains in demand both during times of economic expansion and contraction," he noted, in a recent sponsored article in the Economist.
This kind of rose-coloured commentary is a reminder to keep some perspective when investing in gold. Gold produces no cash flow on which to assign a value and is driven by investor emotions, which can turn on a dime. When the last precious metal boom went bust, too many investors suffered life-altering carnage because they got caught up in the compelling case for gold.
Nonetheless, gold is a reliable diversifier and may be more useful than ever given negligible yields on bonds. The Gold Council's recommendation of a two-to-10-per-cent position in your portfolio is a reasonable one.
Tom Bradley is chair and chief investment officer at Steadyhand Investment Funds, a company that offers individual investors low-fee investment funds and clear-cut advice. He can be reached at [email protected] .
More perspectives on business stories
Analysis: Backing up e-commerce — Ottawa's Rewind secures US$15M venture deal
Why the Bank of Canada could be among the first to raise interest rates
Why luxury brands are more resistant to recessions
Six things not to do when dealing with debt
THE WRAP: Wind-ups, start-ups and songs of the sea
'It's a critical situation:' Dragon's Den star Arlene Dickinson on struggle of small business to survive the second lockdown
Analysis: The NHL's cruel new math
Updated Jan 15, 2021 at 10 a.m.
2020 was a year of extremes for investors, but it shouldn't change your approach going forward
Explainer: COVID-19 vaccine shots add to confusion over China's tests for travelers


text:
Home > Art & Culture > Indian Monuments > Indian Regional Monuments > Monuments of Goa > Fortress of Colvale
Fortress of Colvale
Fortress of Colvale located in North Goa was built in the year 1681 by Alvor. It is at present completely in ruins.
The Fortress of Colvale is located near the Colvale village in the Bardez taluka of North Goa. The fortress was located on the left bank of the Bardez River which was one of the finest trading routes in Goa, and flourished during the rule of the Portuguese, Maratha and the Dutch. The fortress is now in ruins but it still attracts a number of tourists. The journey towards the fortress is exciting and creates historical and archaeological interests. It is also known to be a popular picnic spot.
Colvale is believed to have landmarks of the reign of King Porus who defeated Alexander the Great although no such inscriptions or remnants have been found. Colvale is famous for the abundant availability of 'Murdoshi' (lady fish) and Cashew feni, a local drink.
History of Fortress of Colvale
The Fortress of Colvale was constructed in the year 1681 by the court of Alvor as a barrier to safeguard the Bardez frontier against the Marathas and Bhonsles.
In the year 1739 it was annexed by the Maratha warriors and after 2 years later it was recaptured by the Marquis of Lourical. The fort had a small garrison, besides a regiment. In the year 1841, the regiment was shifted to Mapusa and the fortress lost its importance gradually as for a few years it had been abandoned and neglected.
Architecture of Fortress of Colvale
The fort has the influence of the Portuguese and Hindu architecture. During the stay of the Marathas in this fort, they have re-designed some parts of the monument based on the local architectural style. Though most parts of the fort are ruined, its structural importance can still be comprehended.
The fort was primarily made of brick and stone along with mud. The size of the fort is considered to be quite huge. The exterior end of the fort has walls which are quite high that were important for the Portuguese and the Marathas during their rule as it could help them to stop enemies from entering the fort. It is believed that the interior of the fort once had the bastions and cannons of the Marathas and the Portuguese rulers, but since most parts of the fort has ruined in the present day context, very little traces of the same can be seen.
Attractions of Fortress of Colvale
For many who visit the Ruins of the Fortress of Colvale, the place still holds a charm given its fantastic location and panoramic view of the riverfront. It is a popular picnic spot for most locals and travelers who come to this place.
More Articles in Monuments of Goa (17)
Basilica of Bom Jesus (2)
Se Cathedral (1)
Religious Monuments of Go... (1)
Historical Monuments Of G... (2)
Monuments Of Panaji
Pilar Monastery
Chapora Fort
Cabo de Rama Fort
Reis Magos Fort
Cabo Raj Niwas
Recently Updated Articles in Indian Monuments
• Monuments in North-East India
Monuments in North-east India include some of the ancient historical structures in the state including Sikkim, Manipur, Assam, Arunachal Pradesh, Tripura, Nagaland, Meghalya, and Mizroam. These monuments are remnants of history reflecting cultural heritage of the place.
• Monuments in Jammu
Jammu is the winter capital city of Jammu and Kashmir. It has a huge number of ancient pilgrimage as well as historic monuments and sites.
• Monuments Of Central India
Monuments of Central India comprises the splendid architectural pieces of both Madhya Pradesh and Chattisgarh. The monuments of Central India are widely varied and reflect the perfection in architecture and artistic sense.
• Monuments Of Daman
Monuments of Daman have mostly been constructed under colonial Portuguese influence. The monuments of Daman include forts and churches that are evidence of significant events in the history.churches.
• Monuments Of Diu
Monuments of Diu comprises of a number of forts and churches. These monuments are reminiscent of several historical events of the region. The fort at Diu is one of the most important Portuguese forts in Asia.