64 research outputs found
Spatial risk modeling of cattle depredation by black vultures in the midwestern United States
ock operations through depredation of stock are a cause of human‐wildlife conflict. Management of such conflict requires identifying environmental and non‐environmental factors specific to a wildlife species\u27 biology and ecology that influence the potential for livestock depredation to occur. Identification of such factors can improve understanding of the conditions placing livestock at risk. Black vultures (Coragyps atratus) have expanded their historical range northward into the midwestern United States. Concomitantly, an increase in concern among agricultural producers regarding potential black vulture attacks on livestock has occurred. We estimated area with greater or lesser potential for depredation of domestic cattle by black vultures across a 6‐state region in the midwestern United States using an ensemble of small models (ESM). Specifically, we identified landscape‐scale spatial factors, at a zip code resolution, associated with reported black vulture depredation on cattle in midwestern landscapes to predict future potential livestock depredation. We hypothesized that livestock depredation would be greatest in areas with intensive beef cattle production close to preferred black vulture habitat (e.g., areas with fewer old fields and early successional vegetation paired with more direct edge between older forest and agricultural lands). We predicted that the density of cattle within the county, habitat structure, and proximity to anthropogenic landscape features would be the strongest predictors of black vulture livestock‐depredation risk. Our ESM estimated the relative risk of black vulture‐cattle depredation to be between 0.154–0.631 across our entire study area. Consistent with our hypothesis, areas of greatest predicted risk of depredation correspond with locations that are favorable to vulture life‐history requirements and increased potential to encounter livestock. Our results allow wildlife managers the ability to predict where black vulture depredation of cattle is more likely to occur in the future. It is in these areas where extension and outreach efforts aimed at mitigating this conflict should be focused. Researchers and wildlife managers interested in developing or employing tools aimed at mitigating livestock‐vulture conflicts can also leverage our results to select areas where depredation is most likely to occur
Relationship Between the North Atlantic Oscillation and spring migration phenology of Broad-Winged Hawks (Buteo platypterus) at Hawk Mountain Sanctuary, 1998-2013
Climatic factors influence migration behavior in both short- and long-distance migratory birds. The Broad-winged Hawk (Buteo platypterus) is a long-distance migrant that exhibits a regular calendar-like migration pattern, with some interannual variability during both the northbound and southbound migrations. We examined the relationship between the North Atlantic Oscillation (NAO) and the timing of spring migration in Broad-winged Hawks based on standardized migration count data collected at Hawk Mountain Sanctuary from 1998 to 2013. A strong negative correlation was found between a higher April NAO index and earlier passage dates for the first 50% (r 5 20.723, P , 0.01) and 95% (r 5 20.565, P 5 0.02) and mean passage date (r 5 20.730, P , 0.01) of the hawks passing the watchsite. The April NAO values may serve as a useful indicator of the conditions encountered by Broad-winged Hawks during their northbound migration and our analyses suggest a possible climatic effect on their migration timing, as measured at the migration watchsites in the northeastern United States
Metabolite ratios as potential biomarkers for type 2 diabetes:a DIRECT study
Aims/hypothesis
Circulating metabolites have been shown to reflect metabolic changes during the development of type 2 diabetes. In this study we examined the association of metabolite levels and pairwise metabolite ratios with insulin responses after glucose, glucagon-like peptide-1 (GLP-1) and arginine stimulation. We then investigated if the identified metabolite ratios were associated with measures of OGTT-derived beta cell function and with prevalent and incident type 2 diabetes.
Methods
We measured the levels of 188 metabolites in plasma samples from 130 healthy members of twin families (from the Netherlands Twin Register) at five time points during a modified 3 h hyperglycaemic clamp with glucose, GLP-1 and arginine stimulation. We validated our results in cohorts with OGTT data (n = 340) and epidemiological case–control studies of prevalent (n = 4925) and incident (n = 4277) diabetes. The data were analysed using regression models with adjustment for potential confounders.
Results
There were dynamic changes in metabolite levels in response to the different secretagogues. Furthermore, several fasting pairwise metabolite ratios were associated with one or multiple clamp-derived measures of insulin secretion (all p
Conclusion/interpretation
In this study we have shown that the Val_PC ae C32:2 metabolite ratio is associated with an increased risk of type 2 diabetes and measures of insulin secretion and resistance. The observed effects were stronger than that of the individual metabolites and independent of known risk factors.</p
Cavity-enhanced direct frequency comb spectroscopy
Cavity-enhanced direct frequency comb spectroscopy combines broad spectral
bandwidth, high spectral resolution, precise frequency calibration, and
ultrahigh detection sensitivity, all in one experimental platform based on an
optical frequency comb interacting with a high-finesse optical cavity. Precise
control of the optical frequency comb allows highly efficient, coherent
coupling of individual comb components with corresponding resonant modes of the
high-finesse cavity. The long cavity lifetime dramatically enhances the
effective interaction between the light field and intracavity matter,
increasing the sensitivity for measurement of optical losses by a factor that
is on the order of the cavity finesse. The use of low-dispersion mirrors
permits almost the entire spectral bandwidth of the frequency comb to be
employed for detection, covering a range of ~10% of the actual optical
frequency. The light transmitted from the cavity is spectrally resolved to
provide a multitude of detection channels with spectral resolutions ranging
from a several gigahertz to hundreds of kilohertz. In this review we will
discuss the principle of cavity-enhanced direct frequency comb spectroscopy and
the various implementations of such systems. In particular, we discuss several
types of UV, optical, and IR frequency comb sources and optical cavity designs
that can be used for specific spectroscopic applications. We present several
cavity-comb coupling methods to take advantage of the broad spectral bandwidth
and narrow spectral components of a frequency comb. Finally, we present a
series of experimental measurements on trace gas detections, human breath
analysis, and characterization of cold molecular beams.Comment: 36 pages, 27 figure
The role of micro-cavitation on EHL: a study using a multiscale mass conserving approach
The role of micro-cavitation in Elastohydrodynamic Lubrication is numerically investigated using a multiscale approach whereby both the small scale topographical features and the micro-cavitation of the lubricant due to the features are resolved. Micro-cavitation and the fluid׳s shear-thinning property are modelled at the small scale of topological feature. The effects of topographical features on the film thickness of the line contact bearings and friction coefficient are presented with a focus on the role of micro-cavitation. This highlights how a mass conserving small scale model can be used to model both micro-cavitation and cavitation occurring at the bearing scale, and how topological features can be designed to reduce friction while maintaining bearing load
IgG glycosylation and DNA methylation are interconnected with smoking
Background: Glycosylation is one of the most common post-translation modifications with large influences on protein structure and function. The effector function of immunoglobulin G (IgG) alters between pro- and anti-inflammatory, based on its glycosylation. IgG glycan synthesis is highly complex and dynamic. Methods: With the use of two different analytical methods for assessing IgG glycosylation, we aim to elucidate the link between DNA methylation and glycosylation of IgG by means of epigenome-wide association studies. In total, 3000 individuals from 4 cohorts were analyzed. Results: The overlap of the results from the two glycan measurement panels yielded DNA methylation of 7 CpG-sites on 5 genomic locations to be associated with IgG glycosylation: cg25189904 (chr.1, GNG12); cg05951221, cg21566642 and cg01940273 (chr.2, ALPPL2); cg05575921 (chr.5, AHRR); cg06126421 (6p21.33); and cg03636183 (chr.19, F2RL3). Mediation analyses with respect to smoking revealed that the effect of smoking on IgG glycosylation may be at least partially mediated via DNA methylation levels at these 7 CpG-sites. Conclusion: Our results suggest the presence of an indirect link between DNA methylation and IgG glycosylation that may in part capture environmental exposures. General significance: An epigenome-wide analysis conducted in four population-based cohorts revealed an association between DNA methylation and IgG glycosylation patterns. Presumably, DNA methylation mediates the effect of smoking on IgG glycosylation
Blood-borne parasites in the Black Vulture Coragyps atratus in northwestern Costa Rica
Blood parasites of 17 Black Vultures (Coragyps atratus) were surveyed. The birds were captured from two sites- a garbage dump in Miramar, Puntarenas and a beach in Cuajiniquil, Guanacaste, of Costa Rica. Two blood smears were made per bird, stained, and examined for Haemoproteus, Leucocytozoon, Trypanosoma, Plasmodium and microfilaria presence. Both Plasmodium and microfilaria were found, with an overall prevalence of blood parasites of 70.6% (76.92% in Puntarenas, 50% in Guanacaste). The overall prevalence of Plasmodium was 46.2% and of microfilaria 58.8%. Chi-squared tests revealed capture location had no effect on presence of Plasmodium, while microfilariae were significantly more common at the Puntarenas site. No Haemoproteus, Leucocytozoon, or Trypanosoma were observed at either sit
- …