441 research outputs found
Observer error in identifying species using indirect signs: analysis of a river otter track survey technique
Indirect signs of species presence (e.g., tracks, scats, hairs) are frequently used to
detect target species in occupancy, presence/absence, and other wildlife studies. Indirect
signs are often more efficient than direct observation of elusive animals, making such
signs well suited for long-term and broad-scale monitoring programs. However, error
associated with misidentification of indirect signs can be high, and should be measured
if meaningful inferences about population parameters are to be made. This study
addressed the need for systematic approaches to estimate and minimize variation due to
observer error in identifying indirect signs. I reanalyzed data from 4 replicates of a
presence/absence survey of northern river otters (Lontra canadensis) that had been
conducted by Texas Parks and Wildlife Department (1996-2003). Sixteen observers had
recorded tracks at sample points under bridges (n = 250) distributed throughout 27
counties in the Piney-Woods ecoregion of east Texas. My objectives were to 1)
determine if observers were a source of bias in the survey, 2) estimate the proportion of
error associated with track identification skill, and 3) evaluate the use of an international
certification procedure that measured observer tracking skill. The null hypothesis that observers had no effect on the variation in reported sign was rejected. Indeed, binary
logistic regression tests indicated that observers were significantly associated with
variation in reported track presence. Observers were not randomly distributed among
bridge sites, and therefore were significantly correlated with 4 habitat variables that may
have influenced heterogeneity in otter occupancy and probability of detection
(watershed, vegetation-type, water-type, bridge-area). On average, experienced
observers (n = 7) misidentified 44% of otter tracks, with a range of 0% to 100% correct
detection. Also, 13% of the tracks of species determined to be 'otter-like' were
misidentified as belonging to an otter. During the certification procedure, participants
misidentified the tracks of 12 species as otter. Inaccurate identification of indirect signs
is a likely source of error in wildlife studies. I recommend that observer skill in
identification of indirect signs be measured in order to detect and control for observer
bias in wildlife monitoring
Spatial Ecology and Habitat Selection of Montezuma Quail in Texas
Montezuma quail (Cyrtonyx montezumae) occur throughout desert mountain ranges in the southwestern United States and northern Mexico. Considered a popular game bird in Arizona and New Mexico, they are not hunted in Texas. A hunting season was proposed for the species in 1997 but met with strong objections, most citing the dearth of information about the species. Much of the literature on Montezuma quail ecology is anecdotal or outdated. Previous researchers had problems capturing birds for marking and, once captured, keeping radio-marked birds alive. We used trained pointing dogs and conducted a radiotelemetry study on Montezuma quail in the Davis Mountains of Texas from January 2009 through September 2010. We captured 72 birds and recorded 966 locations. Home ranges were calculated for 13 individuals which had at least 25 locations. A 95% fixed kernel was calculated on each individual giving a mean 6 SD home range of 2,149.4 6 4,736.8 ha. Movements varied widely by individuals and the greatest straight-line movement was 12.7 km. We also performed habitat selection analysis. Mountain savannah ecological sites were preferred across all 3 spatial scales. Our results confirm that home range size and movements by Montezuma quail occur at a much larger scale than previously reported. Thus, managing lands on a larger scale and targeting mountain savannah ecological sites should be considered
Ten-year projection of white-nose syndrome disease dynamics at the southern leading-edge of infection in North America
Predicting the emergence and spread of infectious diseases is critical for the effective conservation of biodiversity. White-nose syndrome (WNS), an emerging infectious disease of bats, has resulted in high mortality in eastern North America. Because the fungal causative agent Pseudogymnoascus destructans is constrained by temperature and humidity, spread dynamics may vary by geography. Environmental conditions in the southern part of the continent are different than the northeast, where disease dynamics are typically studied, making it difficult to predict how the disease will manifest. Herein, we modelled WNS pathogen spread in Texas based on cave densities and average dispersal distances of hosts, projecting these results out to 10 years. We parameterized a predictive model of WNS epidemiology and its effects on bat populations with observed cave environmental data. Our model suggests that bat populations in northern Texas will be more affected by WNS mortality than southern Texas. As such, we recommend prioritizing the preservation of large overwintering colonies of bats in north Texas through management actions. Our model illustrates that infectious disease spread and infectious disease severity can become uncoupled over a gradient of environmental variation and highlight the importance of understanding host, pathogen and environmental conditions across a breadth of environments.Peer reviewe
Mitigation of the instrumental noise transient in gravitational-wave data surrounding GW170817
In the coming years gravitational-wave detectors will undergo a series of
improvements, with an increase in their detection rate by about an order of
magnitude. Routine detections of gravitational-wave signals promote novel
astrophysical and fundamental theory studies, while simultaneously leading to
an increase in the number of detections temporally overlapping with
instrumentally- or environmentally-induced transients in the detectors
(glitches), often of unknown origin. Indeed, this was the case for the very
first detection by the LIGO and Virgo detectors of a gravitational-wave signal
consistent with a binary neutron star coalescence, GW170817. A loud glitch in
the LIGO-Livingston detector, about one second before the merger, hampered
coincident detection (which was initially achieved solely with LIGO-Hanford
data). Moreover, accurate source characterization depends on specific
assumptions about the behavior of the detector noise that are rendered invalid
by the presence of glitches. In this paper, we present the various techniques
employed for the initial mitigation of the glitch to perform source
characterization of GW170817 and study advantages and disadvantages of each
mitigation method. We show that, despite the presence of instrumental noise
transients louder than the one affecting GW170817, we are still able to produce
unbiased measurements of the intrinsic parameters from simulated injections
with properties similar to GW170817.Comment: 11 pages, 3 figures, accepted in PR
Securing the climate benefits of stable forests
Stable forests â those not already significantly disturbed nor facing predictable near-future risks of anthropogenic disturbance â may play a large role in the climate solution, due to their carbon sequestration and storage capabilities. Their importance is recognized by the Paris Agreement, but stable forests have received comparatively little attention through existing forest protection mechanisms and finance. Instead, emphasis has been placed on targeting locations where deforestation and forest degradation are happening actively. Yet stopping deforestation and forest degradation does not guarantee durable success, especially outside the geographic scope of targeted efforts. As a result, today's stable forests may be at risk without additional efforts to secure their long-term conservation.
We synthesize the gaps in existing policy efforts that could address the climate-related benefits derived from stable forests, noting several barriers to action, such as uncertainty around the level of climate services that stable forests provide and difficulties describing the real level of threat posed. We argue that resource and finance allocation for stable forests should be incorporated into countriesâ and donorsâ comprehensive portfolios aimed at tackling deforestation and forest degradation as well as resulting emissions. A holistic and forward-looking approach will be particularly important, given that success in tackling deforestation and forest degradation where it is currently happening will need to be sustained in the long term
Impulsive and self-regulatory processes in risky driving among young people: A dual process model
The present study empirically examined a novel dual process model of self-reported aberrant driving behaviour in young and novice drivers that incorporates both impulsive and self-regulatory processes. Four hundred and nine participants aged 18-25 years (M age = 21.18 years, SD = 2.12; 65.5% females) completed online questionnaires on impulsivity, normlessness, sensation seeking, emotion and self-regulation, and attitudes towards driving safety. Path analysis showed that motor impulsivity was associated with self-reported driving violations, errors, and lapses, whereas sensation seeking was uniquely directly associated with self-reported errors. Non-planning impulsivity, normlessness and sensation seeking had significant indirect effects on self-reported errors, via self-regulation. Finally, motor impulsivity and normlessness had a significant indirect effect on self-reported violations, errors and lapses, via attitudes to driving safety. Based on our findings we suggest that a dual-process approach is relevant to the study of aberrant driving behaviour in young and novice drivers, and the results of the present study have important implications for initiatives to promote driving safety in this population
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
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