37 research outputs found
HI Shells Behind the Coalsack
We report the discovery of two new large HI shells in the direction of the
Coalsack nebula. Both shells were observed with the Parkes Radio Telescope as
part of the Southern Galactic Plane Survey. The largest shell, GSH 304-00-12,
is at a distance of ~1.2 kpc and has derived physical dimensions of 280 x 200
pc. The second shell, GSH 305+01-24, is at a distance of ~2.2 kpc and has
derived dimensions of 280 x 440 pc. We present a simple numerical model to show
that GSH 305+01-24 most likely formed from stellar winds in the Centaurus OB1
stellar association. There is associated radio, infrared and H-alpha continuum
emission. Both shells are situated in the Sagittarius-Carina arm, with GSH
305+01-24 more distant. The far edge of GSH 304-00-12 is at the near side of
the arm and opens into the interarm region. We find no evidence for closure at
the near side of the shell and therefore describe the geometry as conical.
Emission from the near side of the shell may be lost in absorption by the
Coalsack Nebula.Comment: 12 pages, 5 embedded EPS figures, uses emulateapj5.sty. To appear in
the Astrophysical Journal, vol. 56
Pharmaceutical pollution of the world's rivers
Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals
Recommended from our members
Averting biodiversity collapse in tropical forest protected areas
The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenonÂčâ»Âł. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stressesâŽâ»âč. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the worldâs major tropical regions. Our analysis reveals great variation in reserve âhealthâ: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc
Identification of Individual Leopards (Panthera Pardus Kotiya) Using Spot Pattern Variation
Twentyâone captive leopards Panthera pardus kotiya at the National Zoological Gardens in Sri Lanka were individually identified using spot pattern variation, Based on an identification method established for lions (Panthera leo), a code was devised examining 23 variable characters, each of which had one to three values. These characters ranged from number and spacing of muzzle spots to forehead and eye patterns. Correlation among characters to be used for identification was minimized using principal component cluster analysis. The most variable character was chosen from each of eight nonâoverlapping clusters, and frequencies were calculated for each character value. The probability of occurrence of a given spot pattern was calculated as the sum of the frequencies of each character value. From this probability of occurrence, the information content, in bits, was computed for each pattern. The number of bits per character was also calculated. Using the binomial theorem, the reliability of identification was estimated as the sum of the probabilities of zero or one individual having an identical combination of character values. These binomial probabilities exceeded 0.99 for 15 out of 21 animals, and 0.95 for all but two. In these two animals, the information content was low (5.99 and 5.50 bits, respectively) compared to the others, in which information content ranged from 6.87â10.86. Although the mean number of bits (8.5) was theoretically sufficient for a 99% reliable identification, it was concluded that supplementation with an additional character would be worthwhile for identification of individual leopards
Summary of genetic diversity in sloth bears from central India.
<p>Na-Total number of alleles, Ar-Allelic richness, Pr-Private allele richness, He-Expected heterozygosity, Ho-Observed heterozygosity.</p><p>Summary of genetic diversity in sloth bears from central India.</p