Group size and ectoparasitism affect daily survival probability in a colonial bird

Little is known in general about how group size or ectoparasitism affect survival in colonial animals. We estimated daily within-season survival probabilities for nesting adult and recently fledged juvenile cliff swallows (Petrochelidon pyrrhonota) at 239 colonies from 1983 to 2003 in southwestern Nebraska, USA. Some colonies had been fumigated to remove ectoparasites. We conducted mark-recapture at each colony site to estimate daily survival. There were no systematic differences between males and females in daily survival. Adults and juveniles occupying parasite-free colonies had, on average, 4.4% and 62.2% greater daily survival, respectively, than their counterparts in naturally infested colonies. Daily survival of all birds increased with colony size for both parasite-free colonies and those under natural conditions, although the effect was stronger for adults at fumigated sites and for juveniles. Average daily survival probability for adults tended to increase during warmer and drier summers. Although daily survival varied at some sites over the course of the nesting cycle, there were no strongly consistent within-year temporal effects on survival. Even small differences in daily survival probability can translate into large effects on mean lifespan. The deleterious effects of ectoparasites on daily survival within the season represent a previously unknown cost of ectoparasitism. The increase in within-season survival with colony size reflects the net effects of many costs and benefits associated with colony size. Ectoparasitism is probably the most important cost that tends to partly balance the positive effects of large colonies. The greater survival of cliff swallows in the larger colonies is a previously unknown advantage of colonial nesting.Communicated by P. Heeb     

Maternal Serum CA 125 for aneuploidy detection in early pregnancy

Maternal serum CA 125 levels were determined at 9–11 menstrual weeks for 26 cases of trisomy 13 (n = 4), trisomy 18 (n = 7), trisomy 21 (n = 15), and appropriate controls. There were no statistically significant differences between groups.     

Overview of Environmental Hazards and Health Effects of Pollution in Developing Countries: A Case Study of Nigeria

Pollution has taken on a global dimension, and the effects are most obvious in developing countries. The effects take a toll on human health, animals, and vegetation, as well as on soil, air, and water quality. The objective of this article is to discuss the current relationships among pollution, environmental quality, and human health within the frame of anthropogenic activities in developing countries. In addition to personal observations, we review relevant literature on conditions throughout the developing world and case studies on conditions and activities in Nigeria. Key findings show the significant, adverse contributions to human health and environmental risk from current waste generation and handling practices, indoor and outdoor air pollution, wastewater and effluent generation and disposal, the hazardous nature and pollution potential of wastes, and the human behaviors that contribute to pollution in developing countries. There is an urgent need to create awareness among the various segments of society of the human health hazards posed by pollution as well as a need for the comprehensive development and enforcement of appropriate policies to prevent a descent into an abyss of deteriorating human and environmental health.     

Fluorides in groundwater and its impact on health

Fluoride is a naturally occurring toxic mineral present in drinking water and causes yellowing of teeth, tooth problems etc. Fluorspar, Cryolite and Fluorapatite are the naturally occurring minerals, from which fluoride finds its path to groundwater through infiltration. In the present study two groundwater samples, Station I and Station II at Hyderabad megacity, the capital of Andhra Pradesh were investigated for one year from January 2001 to December 2001. The average fluoride values were 1.37 mg/l at Station I and 0.91 mg/l at Station II. The permissible limit given by BIS (1983) 0.6-1.2 mg/l and WHO (1984) 1.5 mg/l for fluoride in drinking water. The groundwaters at Station I exceeded the limit while at Station II it was within the limits. The study indicated that fluoride content of 0.5 mg/l is sufficient to cause yellowing of teeth and dental problems.     

Reactivity of chlorine dioxide with amino acids, peptides, and proteins

Amino acids, proteins, and peptides are found ubiquitously in waters. They can form harmful byproducts during water treatment by reaction with disinfectants. Chlorination and chloramination of water containing natural organic matter is known to result in the production of toxic substances, often referred to as disinfection byproducts. The main advantage of using chlorine dioxide (ClO₂) over other known chlorine-containing disinfectants is the minimization of the formation of harmful trihalomethanes. Because ClO₂ is a promising alternative to other chlorine-containing disinfectants, the chemistry of ClO₂ interactions with amino acids, proteins, and peptides should be understood to ensure the safety of potable water supplies. Here, we present an overview of the aqueous chemistry of ClO₂ and its reactivity with amino acids, peptides, and proteins. The kinetics and products of the reactions are reviewed. Only a few amino acids have been reported to be reactive with ClO₂, and they have been found to follow second-order kinetics for the overall reaction. The rate constants vary from 10^?2 to 10^7?M^?1?s^?1 and follow an order of reactivity: cysteine?>?tyrosine?>?tryptophan?>?histidine?>?proline. For reactions of histidine, tryptophan, and tyrosine with ClO₂, products vary depending largely on the molar ratios of ClO₂ with the specific amino acid. Products of ClO₂ oxidation differ with the presence or absence of oxygen in the reaction mixture. Excess molar amounts of ClO₂ relative to amino acids are associated with the production of low molecular weight compounds. The oxidation of the biochemically important compounds bovine serum albumin and glucose-6-phosphate dehydrogenase by ClO₂ suggests a denaturing of proteins by ClO₂ by an attack on tryptophan and tyrosine residues and relates to the inactivation of microbes by ClO₂.