What Enables Size-Selective Trophy Hunting of Wildlife?

Although rarely considered predators, wildlife hunters can function as important ecological and evolutionary agents. In part, their influence relates to targeting of large reproductive adults within prey populations. Despite known impacts of sizeselective harvests, however, we know little about what enables hunters to kill these older, rarer, and presumably more wary individuals. In other mammalian predators, predatory performance varies with knowledge and physical condition, which accumulates and declines, respectively, with age. Moreover, some species evolved camouflage as a physical trait to aid in predatory performance. In this work, we tested whether knowledge-based faculty (use of a hunting guide with accumulated experience in specific areas), physical traits (relative body mass [RBM] and camouflage clothing), and age can predict predatory performance. We measured performance as do many hunters: size of killed cervid prey, using the number of antler tines as a proxy. Examining ,4300 online photographs of hunters posing with carcasses, we found that only the presence of guides increased the odds of killing larger prey. Accounting for this effect, modest evidence suggested that unguided hunters presumably handicapped with the highest RBM actually had greater odds of killing large prey. There was no association with hunter age, perhaps because of our coarse measure (presence of grey hair) and the performance tradeoffs between knowledge accumulation and physical deterioration with age. Despite its prevalence among sampled hunters (80%), camouflage had no influence on size of killed prey. Should these patterns be representative of other areas and prey, and our interpretations correct, evolutionarily-enlightened harvest management might benefit from regulatory scrutiny on guided hunting. More broadly, we suggest that by being nutritionally and demographically de-coupled from prey and aided by efficient killing technology and road access, wildlife hunters in the developed world might have overcome many of the physical, but not knowledge-based, challenges of hunting

Limited Activity Of Miltefosine In Murine Models Of Cryptococcal Meningoencephalitis And Disseminated Cryptococcosis

Miltefosine is an alkyl phosphocholine with good oral bioavailability and in vitro activity against Cryptococcus species that has gained interest as an additional agent for cryptococcal infections. Our objective was to further evaluate the in vivo efficacy of miltefosine in experimental in vivo models of cryptococcal meningoencephalitis and disseminated cryptococcosis. Mice were infected intracranially or intravenously with either C. neoformans USC1597 or H99. Miltefosine treatment (1.8 to 45 mg/kg of body weight orally once daily) began at either 1 h or 1 day postinoculation. Fluconazole (10 mg/kg orally twice daily) or amphotericin B deoxycholate (3 mg/kg intraperitoneally once daily) served as positive controls. In our standard models, miltefosine did not result in significant improvements in survival or reductions in fungal burden against either C. neoformans isolate. There was a trend toward improved survival with miltefosine at 7.2 mg/kg against disseminated cryptococcosis with the H99 strain but only at a low infecting inoculum. In contrast, both fluconazole and amphotericin B significantly improved survival in mice with cryptococcal meningoencephalitis and disseminated cryptococcosis due to USC1597. Amphotericin B also improved survival against both cryptococcal infections caused by H99. Combination therapy with miltefosine demonstrated neither synergy nor antagonism in both models. These results demonstrate limited efficacy of miltefosine and suggest caution with the potential use of this agent for the treatment of C. neoformans infections.Pharmac

What wild dogs want: habitat selection differs across life stages and orders of selection in a wide-ranging carnivore

Habitat loss is a key threat to the survival of many species. Habitat selection studies provide key information for conservation initiatives by identifying important habitat and anthropogenic characteristics influencing the distribution of threatened species in changing landscapes. However, assumptions about the homogeneity of individual choices on habitat, regardless of life stage, are likely to result in inaccurate assessment of conservation priorities. This study addresses a knowledge gap in how animals at different life stages diverge in how they select habitat and anthropogenic features, using a free-ranging population of African wild dogs living in a human-dominated landscape in Kenya as a case study. Using GPS collar data to develop resource selection function and step selection function models, this study investigated differences between second order (selection of home range across a landscape) and third order (selection of habitat within the home range) habitat selection across four life history stages when resource requirements may vary: resident-non-denning, resident-heavily-pregnant, resident-denning and dispersing

Effects of field-aligned currents in the ionosphere-thermosphere system

Space weather is one of the most significant natural hazards to modern day civilisation, posing a risk to both space and ground infrastructure. It describes the near-Earth and terrestrial environment as affected by the Sun, namely as a result of radiation, interactions with the interplanetary magnetic field and plasma outflow, the latter termed the solar wind. Field-aligned currents (FACs), that is, solar wind-driven currents aligned with the Earth’s geomagnetic field and closed in its ionosphere, play an essential role in the transfer of energy and circulation between the solar wind and the ionosphere-thermosphere system. We study two main consequences of FACs in this system: the induced ground geomagnetic disturbances (GMDs), which arise as FACs close in the ionosphere, and the resultant Joule heating and perturbed thermospheric neutral winds as the energy transferred by FACs dissipates via their closure currents. We find, within data restrictions, no strong linear correlation between FAC and GMD magnitudes, instead suggesting solar wind parameters as a better indication of the location and strength of harmful ground GMDs. We probe the effect a neutral wind disparity between ground-based instrument and satellite measurements will have on the distribution and magnitude of wind-derived Joule heating, after using a model to show the winds should be equivalent. We suggest the cause of the disparity is due to uncertainties in the satellite wind derivation. Finally, we investigate small-scale FAC-driven Joule heating and electron precipitation as the causes of a satellite-measured cusp density enhancement and FPI-measured cusp and nightside auroral oval upwellings. We model an empirical heating source representative of soft and hard precipitation in these regions. Our simulations support a mechanism of soft precipitation and Joule heating in the cusp but are unable to reproduce the nightside upwelling. We suggest this is a storm-related anomaly, requiring an adjusted mechanism

Trace metal fractional solubility in size-segregated aerosols from the tropical eastern Atlantic Ocean

Soluble and total trace metals were measured in four size fractionated aerosol samples collected over the tropical eastern Atlantic Ocean. In samples that were dominated by Saharan dust, the size distributions of total iron, aluminum, titanium, manganese, cobalt, and thorium were very similar to one another and to the size distributions of soluble manganese, cobalt, and thorium. Finer particle sizes (< ~3 μm) showed enhanced soluble concentrations of iron, aluminum, and titanium, possibly as a result of interactions with acidic sulfate aerosol during atmospheric transport. The difference in fine particle solubility between these two groups of elements might be related to the hyperbolic increase in the fractional solubility of iron, and a number of other elements, during the atmospheric transport of Saharan dust, which is not observed for manganese and its associated elements. In comparison to elements whose solubility varies during atmospheric transport, the stability of thorium fractional solubility should reduce uncertainties in the use of dissolved concentrations of this element in seawater as a proxy for dust deposition, although this topic requires further work

Effectiveness of the Pasos Adelante Chronic Disease Prevention and Control Program in a US-Mexico Border Community, 2005-2008

Introducción "Pasos Adelante" es un programa de intervención sobre hábitos saludables facilitado por trabajadores de salud comunitaria o"promotores de salud" destinado a prevenir y controlar enfermedades crónicas en mexicoamericanos. Los estudios iniciales de"Pasos Adelante" mostraron mejoras significativas en la alimentación y la actividad física autorreportadas por los participantes.Este estudio evaluó si los habitantes de una comunidad en la frontera estadounidense que participaron en el programa mostraronmejorías en determinados valores fisiológicos y si los cambios se mantuvieron en el seguimiento a los 3 meses. Métodos El programa se llevó a cabo en sesiones de 12 semanas de enero del 2005 a mayo del 2008 e incluyó grupos de caminata y clases denutrición y actividad física. Se realizaron cuestionarios, mediciones antropométricas y pruebas de laboratorio al inicio delprograma (n = 305), al final (n = 254) y en el seguimiento a los 3 meses (n = 221). Resultados Al compararse los datos iniciales de referencia con los del final del programa, los participantes mostraron reducciones en su índicede masa corporal (P= .04), circunferencia de cintura y cadera (P< .001), presión arterial diastólica y sistólica (P< .001) y colesterol total (P= .008). Ningún valor empeoró significativamente entre la conclusión del programa y el seguimiento, aexcepción de la presión arterial sistólica. Los niveles de glucosa mejoraron entre la finalización y el seguimiento del programa (P=.01). Conclusión Estos resultados sustentan los hallazgos iniciales referidos a la mejoría autorreportada por los participantes en relación conpatrones de alimentación y actividad física al mostrar cambios en medidas objetivas. Este programa basado en la evidenciademuestra el potencial de los programas de control y prevención de enfermedades crónicas llevados a cabo por promotores desalud para mejorar la salud física abordando la prevención primaria y secundaria en organizaciones y comunidades hispanas

Mental Health in the UK Biobank: A Roadmap to Self-Report Measures and Neuroimaging Correlates

The UK Biobank (UKB) is a highly promising dataset for brain biomarker research into population mental health due to its unprecedented sample size and extensive phenotypic, imaging, and biological measurements. In this study, we aimed to provide a shared foundation for UKB neuroimaging research into mental health with a focus on anxiety and depression. We compared UKB self-report measures and revealed important timing effects between scan acquisition and separate online acquisition of some mental health measures. To overcome these timing effects, we introduced and validated the Recent Depressive Symptoms (RDS-4) score which we recommend for state-dependent and longitudinal research in the UKB. We furthermore tested univariate and multivariate associations between brain imaging-derived phenotypes (IDPs) and mental health. Our results showed a significant multivariate relationship between IDPs and mental health, which was replicable. Conversely, effect sizes for individual IDPs were small. Test–retest reliability of IDPs was stronger for measures of brain structure than for measures of brain function. Taken together, these results provide benchmarks and guidelines for future UKB research into brain biomarkers of mental health