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Cold Months (cold + month)
Selected AbstractsMultiyear to daily radon variability from continuous monitoring at the Amram tunnel, southern IsraelGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2010S. M. Barbosa SUMMARY Radon is a naturally occurring radioactive noble gas generated within mineral grains of uranium bearing rocks by alpha decay from radium. The Amram tunnel (A. Bloch Geophysical Observatory) is a particularly suitable location for the investigation of radon variability. Located in the arid environment of the Arava desert, near Elat, the 170 m tunnel that constitutes the observatory enables radon monitoring in a desert environment and under fairly stable environmental conditions. The analysis of the temporal variability of continuous measurements of radon and environmental parameters at the Amram tunnel over a period of several years shows a complex temporal pattern characterized by non-stationary and multiscale features. Radon concentrations exhibit multiyear variability in the form of a increasing trend of ,1000 Bq m,3 yr,1 in the mean and much larger trends up to ,2500 Bq m,3 yr,1 in the maximum radon levels. Radon concentrations also display strong seasonal patterns, with maxima in summer and minima in winter, ranging from 2.5 kBq m,3 in winter to 35 kBq m,3 in summer. Intraseasonal variability is characterized by very large radon anomalies, with sharp increases of more than 20 kBq m,3 relative to the base level, that occur in spring and summer and last for several days. Daily periodic variability with maxima around midnight appears also in spring and summer, being absent in the cold months. Radon variability at seasonal, intraseasonal and daily timescales is associated with the air temperature outside the tunnel, specifically the temperature gradient between the external environment and the more stable environment inside the tunnel where the measurements are performed. [source] How starvation risk in Redshanks Tringa totanus results in predation mortality from Sparrowhawks Accipiter nisusIBIS, Issue 2008WILL CRESSWELL Redshanks Tringa totanus that are preyed upon by Sparrowhawks Accipiter nisus at the Tyninghame Estuary, Firth of Forth, Scotland, provide an example of how the starvation,predation risk trade-off results in mortality. In this trade-off, animals cannot always optimize anti-predation behaviour because anti-predation behaviours, such as avoiding predators, are usually incompatible with foraging behaviours that might maximize intake rates. Therefore, as animals compensate for starvation risk, predation risk increases. Sparrowhawks are the main direct cause of death in Redshanks at Tyninghame. Sparrowhawk attack rate is determined by Redshank vulnerability, and vulnerability decreases as group size and distance to cover increase, and probably as spacing decreases. But reduction of predation vulnerability reduces feeding rate because areas away from cover are less food-profitable and grouping results in increased interference competition. Increased starvation risk in midwinter means Redshanks are forced to feed on highly profitable prey, Orchestia amphipods, the behaviour of which means that Redshanks are forced to feed vulnerably, in widely spaced groups, close to predator-concealing cover. Therefore, it is the constraints that limit the ability of Redshanks to feed in large, dense flocks away from cover that ultimately lead to mortality. We investigate this hypothesis further by testing the prediction that mortality can be predicted directly by cold weather and population density. We demonstrate that the overall number of Redshanks and the proportion of Redshanks killed increase in cold months when controlling for population size. We also demonstrate that the proportion of Redshanks killed increases when there are fewer Redshanks present, because the success rate of hunting Sparrowhawks increases, probably because effective management of predation risk through flocking is constrained by a low population size. Redshanks therefore provide an example of how directly mortality caused by predation arises from starvation risk and other constraints that prevent animals from optimizing anti-predation behaviour. [source] Demographic features and seasonal variations in patients with acne vulgaris in Saudi Arabia: a hospital-based studyINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 12 2002Ali M. Al-Ameer MD Aim To review the demographic features and seasonal variations of acne vulgaris in patients diagnosed at the Dermatology Outpatient Clinic, King Fahad Hospital of the University (KFHU), Al-Khobar, Saudi Arabia. Methods Two hundred and twenty cases (142 females, 78 males; mean age, 14.8 and 16.3 years, respectively) seen between January 1, 1999 and December 31, 2000 were studied. Results Patients suffering from acne vulgaris made up 19.6% of the new cases seen at the clinic. The male to female ratio was 1 : 1.8. The mean age of onset was 16.3 ± 2.1 years for males and 14.8 ± 3.9 years for females (P = 0.003). The largest numbers of patients were seen during the cold months of the year (November to February). Conclusions Acne vulgaris constituted nearly one fifth of all visits to the dermatologist with female predominance. It appears nearly one and a half years earlier in females than in males. Seasonal variations were observed in acne as the condition exacerbates in winter, while if often improves during the summer months. [source] Reproductive parameters of wild Trachypithecus leucocephalus: seasonality, infant mortality and interbirth intervalAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2009Tong Jin Abstract Understanding the reproductive parameters of endangered primate species is vital for evaluating the status of populations and developing adequate conservation measures. This study provides the first detailed analysis of the reproductive parameters of wild white-headed langurs (Trachypithecus leucocephalus), based on demographic data collected over an 8-year period in the Nongguan Karst Hills in Chongzuo County, Guangxi, China. From 1998 to 2002, a total of 133 live births were recorded in the population based on systematic censuses. Births occurred throughout the year, but the temporal pattern was highly correlated with seasonal variation in temperature and rainfall, with the birth peak coinciding with the dry and cold months of November,March. The average birthrate was 0.47±0.13 births per female per year and mortality for infants younger than 20 months was 15.8%. From 1998 to 2006, 14 females gave birth to 41 infants in four focal groups. The average age at first birth for female langurs was 5,6 years (n=5) and the interbirth interval (IBI) was 23.2±5.2 months (median=24.5 months, n=27). Infants are weaned at 19,21 months of age. The IBI for females with infant loss before weaning was significantly shorter than those for females whose infants survived. It appears that birth seasonality in the white-headed langurs is influenced by seasonal changes in food availability. The timing of conceptions was found to coincide with peak food availability. The reproductive parameters for white-headed langurs reported here are quite similar to those reported for other colobine species. One major difference is our observation of lower infant mortality in Trachypithecus. Am. J. Primatol. 71:558,566, 2009. © 2009 Wiley-Liss, Inc. [source] Faecal coliforms in pond water, sediments and hybrid tilapia Oreochromis niloticus×Oreochromis aureus in Saudi ArabiaAQUACULTURE RESEARCH, Issue 7 2003Ahmed H Al-Harbi Abstract Total bacterial load, total coliforms faecal coliforms in pond water, sediment, intestine of hybrid tilapia Oreochromis niloticus×Oreochromis aureus and pigeon Columba livia faeces were investigated monthly over a period of 1 year from July 1999 to June 2000. Fish were collected randomly by a cast net. Samples were analysed for coliforms using the multiple-tube fermentation technique. Results showed total viable bacterial counts in the pond water, sediment, intestine of tilapia and pigeon faeces ranging from 1.8±0.9×102 to 6.0±1.2×104 cfu mL,1, 3.2±1.2×105 to 2.8±1.5×107 cfu g,1, 8.2±1.6×105 to 9.9±1.5×107 cfu g,11.0±0.4×107to9.7±0.2×109 cfu g,1respectively. The most probable number (MPN) of coliforms and faecal coliforms ranged from 287±12 to ,1600±0 100 mL,1 in pond water; the MPN ranges for sediment, tilapia intestine and pigeon faeces were 257±29 to ,1100±0 g,1, 237±46 to ,1100±0 g,1 and 403±98 to ,1100±0 g,1 respectively. The abundance of normal bacteria coliforms was greater in the warm months than in the cold months. Ground water was free from any sort of coliform organisms, and there were no sources of human faecal matter in the pond. So, it is clear that faecal coliforms from pigeon faeces significantly contaminated (P<0.05) the ponds and tilapia intestines. Escherichia coli was the only coliform organism found in pond water, sediment, intestine of tilapia and pigeon faeces. [source] | |||||||||||||