1,624 research outputs found
CALL BROADCASTING AND AUTOMATED RECORDERS AS TOOLS FOR ANURAN SURVEYS IN A SUBARCTIC TUNDRA LANDSCAPE
Relatively little is known about population ecology of anurans in arctic and subarctic tundra regions, in part because it is difficult to survey anurans in these landscapes. Anuran survey protocols developed for temperate regions have limited applicability in arctic and subarctic tundra landscapes, which may lack roads and vehicle access, and experience variable and inclement weather during short anuran breeding seasons. To evaluate approaches to address some of the limitations of surveying anurans in tundra landscapes, we assessed the effectiveness of using breeding call broadcasts to increase detection of Boreal Chorus Frogs (Pseudacris maculata) and Wood Frogs (Lithobates sylvaticus) near Cape Churchill, Manitoba, Canada. We also evaluated how counts of anurans derived from automated audio recorders compared with those obtained simultaneously by observers. We detected on average 0.4 additional Wood Frogs per survey when we broadcasted calls (x = 0.82, SD = 1.38), an increase of > 40% compared to surveys without broadcasts (x = 1.24, SD = 1.51; Wilcoxon test; Z = 2.73, P = 0.006). In contrast, broadcasting Boreal Chorus Frog calls did not increase the number of chorus frog detections (Wilcoxon test; Z < 0.001, P > 0.90). Detections of Wood Frogs in a 100-m radius were lower via automated recorders (x = 0.60, SD = 0.87 SD) than by observers during simultaneous surveys (x = 0.96, SD = 1.27 Z = 2.07, P = 0.038), but those of Boreal Chorus Frogs were not different (x = 1.72, SD = 1.31;x = 1.44, SD = 1.5; Z = 1.55, P > 0.121). Our results suggest that broadcasting calls can increase detection of Wood Frogs, and that automated recorders are useful in detecting both Wood Frogs and Boreal Chorus Fogs in arctic and subarctic tundra landscapes
Post-transcriptional regulation of satellite cell quiescence by TTP-mediated mRNA decay.
Skeletal muscle satellite cells in their niche are quiescent and upon muscle injury, exit quiescence, proliferate to repair muscle tissue, and self-renew to replenish the satellite cell population. To understand the mechanisms involved in maintaining satellite cell quiescence, we identified gene transcripts that were differentially expressed during satellite cell activation following muscle injury. Transcripts encoding RNA binding proteins were among the most significantly changed and included the mRNA decay factor Tristetraprolin. Tristetraprolin promotes the decay of MyoD mRNA, which encodes a transcriptional regulator of myogenic commitment, via binding to the MyoD mRNA 3' untranslated region. Upon satellite cell activation, p38α/β MAPK phosphorylates MAPKAP2 and inactivates Tristetraprolin, stabilizing MyoD mRNA. Satellite cell specific knockdown of Tristetraprolin precociously activates satellite cells in vivo, enabling MyoD accumulation, differentiation and cell fusion into myofibers. Regulation of mRNAs by Tristetraprolin appears to function as one of several critical post-transcriptional regulatory mechanisms controlling satellite cell homeostasis
Breast cancer risk is increased in the years following false-positive breast cancer screening
A small number of studies have investigated breast cancer (BC) risk among women with a history of false-positive recall (FPR) in BC screening, but none of them has used time-to-event analysis while at the same time quantifying the effect of false-negative diagnostic assessment (FNDA). FNDA occurs when screening detects BC, but this BC is missed on diagnostic assessment (DA). As a result of FNDA, screenings that detected cancer are incorrectly classified as FPR. Our study linked data recorded in the Flemish BC screening program (women aged 50-69 years) to data from the national cancer registry. We used Cox proportional hazards models on a retrospective cohort of 298 738 women to assess the association between FPR and subsequent BC, while adjusting for potential confounders. The mean follow-up was 6.9 years. Compared with women without recall, women with a history of FPR were at an increased risk of developing BC [hazard ratio = 2.10 (95% confidence interval: 1.92-2.31)]. However, 22% of BC after FPR was due to FNDA. The hazard ratio dropped to 1.69 (95% confidence interval: 1.52-1.87) when FNDA was excluded. Women with FPR have a subsequently increased BC risk compared with women without recall. The risk is higher for women who have a FPR BI-RADS 4 or 5 compared with FPR BI- RADS 3. There is room for improvement of diagnostic assessment: 41% of the excess risk is explained by FNDA after baseline screening
IARC Monographs: 40 Years of Evaluating Carcinogenic Hazards to Humans
Background: Recently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.
Objectives: The authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed.
Discussion: We concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.
Conclusions: The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public’s health
Evaluating GAIA performances on eclipsing binaries. II. Orbits and stellar parameters for V781 Tau, UV Leo and GK Dra
The orbits and physical parameters of three close, double-lined G0 eclipsing
binaries have been derived combining H_P, V_T, B_T photometry from the
Hipparcos/Tycho mission with 8480-8740 \AA ground-based spectroscopy. The setup
is mimicking the photometric and spectroscopic observations that should be
obtained by GAIA. The binaries considered here are all of G0 spectral type, but
each with its own complications: V781 Tau is an overcontact system with
components of unequal temperature, UV Leo shows occasional surface spots and GK
Dra contains a delta-Scuti variable. Such peculiarities will be common among
binaries to be discovered by GAIA. We find that the values of masses, radii and
temperatures for such stars can be derived with a 1-2% accuracy using the
adopted GAIA-like observing mode.Comment: accepted for publication in Astronomy and Astrophysics, contains 5
Tables and 3 Figures; correction of an important typ
Codimension three bifurcation of streamline patterns close to a no-slip wall: A topological description of boundary layer eruption
Policy Environment and Public Service Motivation
This article analyzes whether and to what extent the policy environment of civil servants has an
impact on their level of Public Service Motivation (PSM). It hypothesizes that public employees
working in different policy domains and stages of the policy cycle are diversely motivated by four
PSM orientations (Compassion, Commitment to the public interest, Self-sacrifice and Attraction to
politics). The empirical results are based on a survey of 6885 Swiss civil servants. They show that
those in charge of Welfare State policies are inclined to have higher levels of 'Compassion', whereas
those performing core state functions report lower levels. Furthermore, employees whose main
tasks are related to policy formulation display high levels of the 'Attraction to politics' dimension
of PSM. This study questions the generalization of previous findings on PSM that are based on
heterogeneous survey populations
Correlations among Multi-Wavelength Luminosities of Star-Forming Galaxies
It has been known for two decades that a tight correlation exists between
far-infrared (FIR) and radio (1.4 and 4.8 GHz) global fluxes/luminosities from
galaxies, which may be explained in terms of massive star formation activities
in these galaxies. For this very reason, a correlation might also exist between
X-ray and FIR/radio global luminosities of galaxies. We analyze data from {\it
ROSAT} All-Sky Survey and {\it IRAS} to show that such correlation does indeed
exist between FIR (42.5m) and soft X-ray (0.12.4keV) luminosities
in active star-forming galaxies (ASFGs).In order to establish a physical
connection between the L_{\rmX}-L_{\rm FIR} correlation and global star
formation rate (SFR) in galaxies, we empirically derive both and relations. Futhermore, we propose a relation
between soft X-ray luminosity and SFR in star-forming galaxies. To further
understand the relation, we construct an empirical
model in which both FIR and X-ray emissions consist of two components with one
being closely associated with star formation and the other not.Comment: 9 pages, 6 figures, accepted by MNRA
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