In species that lay their eggs in rafts, rafts do not form adventitiously; the female Culex settles carefully on still water with its hind legs crossed, and as it lays the eggs one by one, it twitches to arrange them into a head-down array that sticks together to form the raft.Aedes females generally drop their eggs singly, much as Anopheles do, but not as a rule into water. Instead, they lay their eggs on damp mud or other surfaces near the waters edge. Such an oviposition site commonly is the wall of a cavity such as a hollow stump or a container such as a bucket or a discarded vehicle tire. The eggs generally do not hatch until they are flooded, and they may have to withstand considerable desiccation before that happens. They are not resistant to desiccation straight after oviposition, but must develop to a suitable degree first. After that, they can enter diapause for several months if they dry out. Clutches of eggs of the majority of mosquito species hatch as soon as possible, and all the eggs in the clutch hatch at much the same time. In contrast, a batch of Aedes eggs in diapause tends to hatch irregularly over an extended period of time. This makes it much more difficult to control such species than those mosquitoes whose larvae can be killed all together as they hatch. Some Anopheles species do also behave in such a manner, though not to the same degree of sophistication.
The prevalence of hypocholesterolemia in the elderly ranges between 2% to 36%, depending on specific cutoff levels and age range investigated. Alerting physicians to hypocholesterolemia may benefit some of their patients who take cholesterol-lowering drugs and decrease the rate of their emergency room visits. Critical illness
In the setting of critical illness, low cholesterol levels are predictive of clinical deterioration, and are correlated with altered cytokine levels. Causes
Possible causes of low cholesterol are:
statins
hyperthyroidism, or an overactive thyroid gland
adrenal insufficiency
liver disease
malabsorption (inadequate absorption of nutrients from the intestines), such as in celiac disease
malnutrition
abetalipoproteinemia - a rare genetic disease that causes cholesterol readings below 50 mg/dL. It is found mostly in Jewish populations. hypobetalipoproteinemia - a genetic disease that causes cholesterol readings below 50 mg/dL
manganese deficiency
Smith–Lemli–Opitz syndrome
Marfan syndrome
leukemias and other hematological diseases

Diagnosis
Classification
According to the American Heart Association in 1994, only total cholesterol levels below 160 mg/dL or 4.1 mmol/L are to be classified as "hypocholesterolemia". However, this is not agreed on universally and some put the level lower. References


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