28 research outputs found
Performance benchmarks for scholarly metrics associated with fisheries and wildlife faculty
Research productivity and impact are often considered in professional evaluations of academics, and performance metrics based on publications and citations increasingly are used in such evaluations. To promote evidence-based and informed use of these metrics, we collected publication and citation data for 437 tenure-track faculty members at 33 research-extensive universities in the United States belonging to the National Association of University Fisheries and Wildlife Programs. For each faculty member, we computed 8 commonly used performance metrics based on numbers of publications and citations, and recorded covariates including academic age (time since Ph.D.), sex, percentage of appointment devoted to research, and the sub-disciplinary research focus. Standardized deviance residuals from regression models were used to compare faculty after accounting for variation in performance due to these covariates. We also aggregated residuals to enable comparison across universities. Finally, we tested for temporal trends in citation practices to assess whether the law of constant ratios , used to enable comparison of performance metrics between disciplines that differ in citation and publication practices, applied to fisheries and wildlife sub-disciplines when mapped to Web of Science Journal Citation Report categories. Our regression models reduced deviance by 1/4 to 1/2. Standardized residuals for each faculty member, when combined across metrics as a simple average or weighted via factor analysis, produced similar results in terms of performance based on percentile rankings. Significant variation was observed in scholarly performance across universities, after accounting for the influence of covariates. In contrast to findings for other disciplines, normalized citation ratios for fisheries and wildlife sub-disciplines increased across years. Increases were comparable for all sub-disciplines except ecology. We discuss the advantages and limitations of our methods, illustrate their use when applied to new data, and suggest future improvements. Our benchmarking approach may provide a useful tool to augment detailed, qualitative assessment of performance. © 2016 Swihart et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Discovery, Timing, and Multiwavelength Observations of the Black Widow Millisecond Pulsar PSR J1555-2908
We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 M ⊙. This fast and energetic ( Ė=3×1035 erg s-1) millisecond pulsar was first detected as a gamma-ray point source in Fermi Large Area Telescope (LAT) sky survey observations. Guided by a steep-spectrum radio point source in the Fermi error region, we performed a search at 820 MHz with the Green Bank Telescope that first discovered the pulsations. The initial radio pulse timing observations provided enough information to seed a search for gamma-ray pulsations in the LAT data, from which we derive a timing solution valid for the full Fermi mission. In addition to the discovery and timing of radio and gamma-ray pulsations, we searched for X-ray pulsations using NICER but no significant pulsations were detected. We also obtained time-series r-band photometry that indicates strong heating of the companion star by the pulsar wind. Material blown off the heated companion eclipses the 820 MHz radio pulse during inferior conjunction of the companion for ≈10% of the orbit, which is twice the angle subtended by its Roche lobe in an edge-on system. © 2022. The Author(s). Published by the American Astronomical Society
Discovery, Timing, and Multiwavelength Observations of the Black Widow Millisecond Pulsar PSR J1555-2908
We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray
pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052
. This fast and energetic ( erg/s)
millisecond pulsar was first detected as a gamma-ray point source in Fermi LAT
sky survey observations. Guided by a steep spectrum radio point source in the
Fermi error region, we performed a search at 820 MHz with the Green Bank
Telescope that first discovered the pulsations. The initial radio pulse timing
observations provided enough information to seed a search for gamma-ray
pulsations in the LAT data, from which we derive a timing solution valid for
the full Fermi mission. In addition to the radio and gamma-ray pulsation
discovery and timing, we searched for X-ray pulsations using NICER but no
significant pulsations were detected. We also obtained time-series r-band
photometry that indicates strong heating of the companion star by the pulsar
wind. Material blown off the heated companion eclipses the 820 MHz radio pulse
during inferior conjunction of the companion for ~10% of the orbit, which is
twice the angle subtended by its Roche lobe in an edge-on system.Comment: 15 pages, 6 figures, accepted by Ap
Modeling Routes of Chronic Wasting Disease Transmission: Environmental Prion Persistence Promotes Deer Population Decline and Extinction
Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose transmitted through direct, animal-to-animal contact, and indirectly, via environmental contamination. Considerable attention has been paid to modeling direct transmission, but despite the fact that CWD prions can remain infectious in the environment for years, relatively little information exists about the potential effects of indirect transmission on CWD dynamics. In the present study, we use simulation models to demonstrate how indirect transmission and the duration of environmental prion persistence may affect epidemics of CWD and populations of North American deer. Existing data from Colorado, Wyoming, and Wisconsin's CWD epidemics were used to define plausible short-term outcomes and associated parameter spaces. Resulting long-term outcomes range from relatively low disease prevalence and limited host-population decline to host-population collapse and extinction. Our models suggest that disease prevalence and the severity of population decline is driven by the duration that prions remain infectious in the environment. Despite relatively low epidemic growth rates, the basic reproductive number, R0, may be much larger than expected under the direct-transmission paradigm because the infectious period can vastly exceed the host's life span. High prion persistence is expected to lead to an increasing environmental pool of prions during the early phases (i.e. approximately during the first 50 years) of the epidemic. As a consequence, over this period of time, disease dynamics will become more heavily influenced by indirect transmission, which may explain some of the observed regional differences in age and sex-specific disease patterns. This suggests management interventions, such as culling or vaccination, will become increasingly less effective as CWD epidemics progress
Reproducibility of regional cerebral blood measurements : menstrual cycle and run order effects
The present study investigated the effects of menstruation and run order on the reproducibility of regional cerebral blood flow measurements (rCBF) across time. Twenty female subjects were utilized within a two- group crossover design. Two rCBF measurements were performed per subject under conditions of minimal external sensory stimulation. Measurements were obtained during premenstrual and postmenstrual cycle phases. Quantification of menstrually related symptomology, anxiety, and numerous physiological parameters was performed at each measurement point. Nonparametric statistical analyses revealed no significant effect of either phase of menstrual cycle or run order. Prevalence and severity of menstrually related symptomology was significantly greater prior to premenstrual measurements. Degree of anxiety was significantly greater prior to first rCBF measurements. Change in rCBF across time was negatively correlated with change in respiration rate and mean arterial blood pressure. The effect of differing intermeasure interval lengths on the reproducibility of rCBF measurements, across time is discussed.Psychology, Department o
Texas Research Institute of Mental Sciences Therapy Notes
Brief, monthly newsletter of the Texas Research Institute of Mental Sciences featuring articles by staff specialists on current treatments and other topics of importance to clinicians in the mental health profession. This issue discusses "Neuropsychological assessment of the aged patient.
Cache placement, pilfering, and a recovery advantage in a seed-dispersing rodent: Could predation of scatter hoarders contribute to seedling establishment? Acta OecologicaInternational
a b s t r a c t Scatter-hoarding mammals are thought to rely on spatial memory to relocate food caches. Yet, we know little about how long these granivores (primarily rodents) recall specific cache locations or whether individual hoarders have an advantage when recovering their own caches. Indeed, a few recent studies suggest that high rates of pilferage are common and that individual hoarders may not have a retriever's advantage. We tested this hypothesis in a high-density (>7 animals/ha) population of eastern gray squirrels (Sciurus carolinensis) by presenting individually marked animals (>20) with tagged acorns, mapping cache sites, and following the fate of seed caches. PIT tags allowed us to monitor individual seeds without disturbing cache sites. Acorns only remained in the caches for 12e119 h (0.5e5 d). However, when we livetrapped and removed some animals from the site immediately after they stored seeds (thus simulating predation), their seed caches remained intact for significantly longer periods (16e27 d). Cache duration corresponded roughly to the time at which squirrels were returned to the study area. These results suggest that squirrels have a retriever's advantage and may remember specific cache sites longer than previously thought. We further suggest that predation of scatter hoarders who store seeds for long periods and also possess a recovery advantage may be one important mechanism by which seed establishment is achieved
Citation practices in fisheries and wildlife sub-disciplines do not obey the law of constant ratios.
<p>Eighteen categories from Web of Science Journal Citation Reports<sup>®</sup> were clustered into the 7 sub-disciplinary categories (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155097#pone.0155097.t002" target="_blank">Table 2</a>) to derive annual averages for citations per article, normalized to mathematics. Ratios increased over time, with comparable rates except for ecology.</p