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Earth and Environmental Science	50%

Selected Abstracts

Proximity to the US,Mexico border: a key to explaining geographic variation in US methamphetamine, cocaine and heroin purity

ADDICTION, Issue 10 2010
James K. Cunningham
ABSTRACT Aims Although illicit drug purity is a widely discussed health risk, research explaining its geographic variation within a country is rare. This study examines whether proximity to the US,Mexico border, the United States' primary drug import portal, is associated with geographic variation in US methamphetamine, heroin and cocaine purity. Design Distances (proximity) between the US,Mexico border and locations of methamphetamine, cocaine and heroin seizures/acquisitions (n = 239 070) recorded in STRIDE (System to Retrieve Information from Drug Evidence) were calculated for the period of 1990,2004. The association of drug purity with these distances and other variables, including time and seizure/acquisition size, was examined using hierarchical multivariate linear modeling (HMLM). Setting Coterminous United States. Findings Methamphetamine, cocaine and heroin purity generally decreased with distance from the US,Mexico border. Heroin purity, however, after initially declining with distance, turned upwards,a U-shaped association. During 2000,04, methamphetamine purity also had a U-shaped association with distance. For each of the three drugs, temporal changes in the purity of small acquisitions (<10 g) were typically more dynamic in areas closer to the US,Mexico border. Conclusions Geographic variance in methamphetamine, cocaine and heroin purity throughout the coterminous United States was associated with US,Mexico border proximity. The U-shaped associations between border-distance and purity for heroin and methamphetamine may be due to imports of those drugs via the eastern United States and southeast Canada, respectively. That said, areas closer to the US,Mexico border generally had relatively high illicit drug purity, as well as more dynamic change in the purity of small (,retail level') drug amounts. [source]

Differential mortality of wintering shorebirds on the Banc d'Arguin, Mauritania, due to predation by large falcons

IBIS, Issue 2008
PIET J. VAN DEN HOUT
Predators may influence many aspects of the daily life and seasonal movements of their prey. Here we quantify direct, and evaluate indirect effects of predation by three falcon species (Lanner Falcon Falco biarmicus, Barbary Falcon Falco pelegrinoides and Peregrine Falcon Falco peregrinus) on coastal shorebirds wintering on the Banc d'Arguin, Mauritania, an area hosting approximately 30% of the East Atlantic Flyway population of shorebirds. On the basis of 754 h of observation over five winters, 97 witnessed attacks and 585 collected prey remains, we show that shorebirds were safer in larger flocks, which tended to be attacked less often. Furthermore, species that forage relatively close to shore and in small flocks were depredated more often than expected from their relative abundance. In three species, Red Knot Calidris canutus canutus, Bar-tailed Godwit Limosa lapponica taymyrensis and Dunlin Calidris alpina, the juveniles were more vulnerable than adults. We estimated that on average 1% of the juvenile and 0.1% of the adult Red Knots present were killed by large falcons each winter. For Red Knots we simultaneously quantified annual survival on the basis of an individual colour-marking programme: mortality due to predation by falcons accounted for an estimated 6.2% (juveniles) and 0.8% (adults) of annual mortality. We suggest that juvenile Red Knots are 10 times as likely to be killed by falcons because they use riskier habitats, i.e. early and late tide foraging areas closer to shores where surprise attacks are both more common and more successful. These results indicate that the strength of indirect effects of predation operating in a shorebird population largely outweigh the effects of mortality per se. [source]

Responses of large volcanic eruptions in the instrumental and documentary climatic data over Central Europe

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 4 2006
Jan Písek
Abstract Responses of large volcanic eruptions in selected long temperature series from Austria, the Czech Republic and Germany as well as in three global radiation series in Central Europe are studied. In the example of seven large tropical eruptions (Krakatau 1883; Pelée, Soufriére and Santa María 1902; Agung, 1963; El Chichón, 1982; Mt Pinatubo, 1991) it has been demonstrated that volcanic signal in regional series is not so strongly expressed as in the hemispheric scale owing to different local effects and circulation patterns. This is also valid in the case of two further discussed eruptions of Tambora (1815) and Katmai (1912). The responses of eruptions in areas closer to Central Europe such as Iceland or Italy are more important. In nine analysed cases with VEI = 4,5 with a single exception of the Hekla eruption (1917), cold seasons were observed to follow the eruption. Responses to the Lakagígar eruption (1783) of Iceland with important impacts are also discussed in detail. Moreover, correlation between temperatures (annual and winter half-year series) and NAOI is prevailingly smaller for the period following eruptions than in the period preceding eruptions. The importance of documentary evidence as a valuable source of the information about the impacts of volcanic eruptions is demonstrated. Copyright © 2006 Royal Meteorological Society. [source]

Moon phase and nocturnal density of Atlantic salmon parr in the Sainte-Marguerite River, Québec

JOURNAL OF FISH BIOLOGY, Issue 1 2005
I. Imre
Nocturnal underwater counts of Atlantic salmon Salmo salar parr were made on four consecutive occasions (two lunar cycles, samplings at both the full and new moon) at four 40 m long sites in the Sainte-Marguerite River, Québec, Canada, between 30 June and 14 August 2003. Atlantic salmon parr counts did not differ significantly between moon phases. Cloud cover ranged from 0 to 100% during the study, and had no significant effect on parr counts. There were significantly more Atlantic salmon parr in the near shore than in the midstream areas. The findings of this study suggest that the sampling strategy of summer studies aimed at assessing population abundance or developing habitat quality models can be designed without taking moon phase or cloud cover into consideration, but it should account for the higher relative abundance of Atlantic salmon parr in the near shore areas as compared to areas closer to the middle of streams. [source]