Bringing together the viewpoints of leading experts in taxonomy, ecology and biogeography of different taxa, this book synthesises discussion surrounding the so-called 'everything is everywhere' ...hypothesis. It addresses the processes that generate spatial patterns of diversity and biogeography in organisms that can potentially be cosmopolitan. The contributors discuss questions such as: are microorganisms (e.g. prokaryotes, protists, algae, yeast and microscopic fungi, plants and animals) really cosmopolitan in their distribution? What are the biological properties that allow such potential distribution? Are there processes that would limit their distribution? Are microorganisms intrinsically different from macroscopic ones? What can microorganisms tell us about the generalities of biogeography? Can they be used for experimental biogeography? Written for graduate students and academic researchers, the book promotes a more complete understanding of the spatial patterns and the general processes in biogeography.
The fish faunas of continental South and Central America constitute one of the greatest concentrations of aquatic diversity on Earth, consisting of about 10 percent of all living vertebrate species. ...Historical Biogeography of Neotropical Freshwater Fishes explores the evolutionary origins of this unique ecosystem. The chapters address central themes in the study of tropical biodiversity: why is the Amazon basin home to so many distinct evolutionary lineages? What roles do ecological specialization, speciation, and extinction play in the formation of regional assemblages? How do dispersal barriers contribute to isolation and diversification? Focusing on whole faunas rather than individual taxonomic groups, this volume shows that the area's high regional diversity is not the result of recent diversification in lowland tropical rainforests. Rather, it is the product of species accumulating over tens of millions of years and across a continental arena.
This comprehensive handbook covers all the rodents occurring in Southern, Central, East and West Africa, south of the Sahara. Genus and species accounts include diagnostic descriptions, systematics ...and taxonomy, biogeographical environment, fossil species, photographs of skull and mandible, illustrations of molar dentition, photographs of live animals, distribution maps and tables of standard museum measurements.
Sharp exacerbations of the US overdose crisis are linked to polysubstance use of synthetic compounds. Xylazine is a veterinary tranquilizer, long noted in the street opioid supply of Puerto Rico, and ...more recently Philadelphia. Yet its national trends, geographic distribution, and health risks are poorly characterized.
In this sequential mixed-methods study, xylazine was increasingly observed by ethnographers in Philadelphia among drug-sellers and people who inject drugs (PWID). Subsequently, we systematically searched for records describing xylazine-present overdose mortality across the US and assessed time trends and overlap with other drugs.
In 10 jurisdictions – representing all four US Census Regions – xylazine was increasingly present in overdose deaths, rising from 0.36% of deaths in 015m 6.7% in 2020. The highest xylazine prevalence data was observed in Philadelphia, (25.8% of deaths), followed by Maryland (19.3%) and Connecticut (10.2%). Illicitly-manufactured-fentanyls were present in 98.4% of xylazine-present-overdose-deaths – suggesting a strong ecological link – as well as cocaine (45.4%), benzodiazepines (28.4%), heroin (23.3%), and alcohol (19.7%). PWID in Philadelphia described xylazine as a sought-after adulterant that lengthens the short duration of fentanyl injections. They also linked it to increased risk of soft tissue infection and naloxone-resistant overdose.
Xylazine is increasingly present in overdose deaths, linked to the proliferation of illicitly-manufactured-fentanyls. Ethnographic accounts associate it with profound risks for PWID. Nevertheless, many jurisdictions do not routinely test for xylazine, and it is not comprehensively tracked nationally. Further efforts are needed to provide PWID with services that can help minimize additional risks associated with a shifting drug supply.
•Xylazine (veterinary tranquilizer) increasingly involved in overdose in all Census Regions.•Among 10 jurisdictions, prevalence rose from 0.36% of overdose deaths in 2015 to 6.7% in 2020.•Fentanyl was found in 98% of xylazine-involved deaths, suggesting strong link.•Ethnographic data suggest xylazine increases short duration of fentanyl, adds euphoria.•Xylazine presents novel health risks, e.g. abscesses, naloxone-resistant overdose.
Atmospheric blocking due to anomalous, persistent meandering of the jet stream often causes weather extremes in the midlatitudes. Despite its ubiquity, the onset mechanism of blocking is not well ...understood. Here we demonstrate with meteorological data that there exists a close analogy between blocking and traffic congestion on a highway, and that they can be described by a common mathematical theory. The theory predicts that the jet stream has a capacity for the flux of wave activity (a measure of meandering), just as the highway has traffic capacity, and when it is exceeded, blocking manifests as congestion. Stationary waves modulate the jet stream's capacity for transient waves and localize block formation. Climate change likely affects blocking frequency by modifying the jet stream's proximity to capacity.
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