3,167 research outputs found
Identification and evaluation of grizzly bear habitat in the Bob Marshall Wilderness Area Montana
Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana
We estimated grizzly bear (Ursus arctos) population vital rates and trend for the Northern Continental Divide Ecosystem, Montana, between 2004–2009 by following radio-collared females and observing their fate and reproductive performance. Our estimates of dependent cub and yearling survival were 0.612 (95% CI = 0.300–0.818) and 0.682 (95% CI= 0.258–0.898). Our estimates of subadult and adult female survival were 0.852 (95% CI = 0.628–0.951) and 0.952 (95% CI = 0.892–0.980). From visual observations, we estimated a mean litter size of 2.00 cubs/litter. Accounting for cub mortality prior to the first observations of litters in spring, our adjusted mean litter size was 2.27 cubs/litter. We estimated the probabilities of females transitioning from one reproductive state to another between years. Using the stable state probability of 0.322 (95% CI = 0.262–0.382) for females with cub litters, our adjusted fecundity estimate (mx) was 0.367 (95% CI = 0.273–0.461). Using our derived rates, we estimated that the population grew at a mean annual rate of approximately 3 percent (? = 1.0306, 95% CI = 0.928–1.102), and 71.5% of 10,000 Monte Carlo simulations produced estimates of ? > 1.0. Our results indicate an increasing population trend of grizzly bears in the NCDE. Coupled with concurrent studies of population size, we estimate that approximately 1000 grizzly bears reside in and adjacent to this recovery area. We suggest that monitoring of population trend and other vital rates using radioed females be continued
A Comparison of Risk Exposure in Aquaculture and Agricultural Businesses
Agriculture and aquaculture have common features associated with their biological nature affecting risk exposure of the businesses. The aim of this paper is to compare risk exposure in salmon farming and agricultural enterprises in Norway by using an implicit error component model to examine the risk structure of yields, prices and economic returns at the farm level. Results indicate a higher farm-level year-to-year variability in yields, prices and economic returns in salmon farming than in agricultural enterprises. The variability in livestock enterprises was generally lower than for crop enterprises. Return on assets was highest in salmon farming with an average annual return of 9.2%. All of the agricultural farm types exhibited a negative average return on assets on average. Stochastic dominance tests of the distribution of economic returns from aquaculture and agricultural farm types showed salmon farming to be the most risk efficient alternative and salmon farming was most attractive from an investor’s perspective.Risk analysis, variability, Norway, Risk and Uncertainty,
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Treatment of Tuberculosis in Complex Emergencies in Developing Countries: A Scoping Review
Almost 172 million people live in complex emergencies globally resulting from political and/or economic instability. The provision and continuity of health care in complex emergencies remain a significant challenge. Health agencies are often hesitant to implement tuberculosis programmes in particular because its treatment requires a longer commitment than most acute diseases. However, not treating tuberculosis promptly increases mortality and untreated tuberculosis further increases the incidence of tuberculosis. Given that complex emergencies are increasing globally, there is an urgent need to analyse the available evidence to improve our understanding of how best to deliver tuberculosis programmes in such settings. Using a scoping review method, we selected and analysed fifteen studies on tuberculosis programmes in complex emergencies. We found that despite the challenges, tuberculosis programmes have been successful in complex emergencies. We identified seven cross-cutting factors that were found to be important: service providers and treatment regime, training and supervision, donor support, adherence, leadership and coordination, monitoring, and government and community support. In general, programmes showed greater creativity and flexibility to adapt to the local conditions and at times, it also meant diverting from the WHO guidelines. We identify areas of further research including the need to study the effectiveness of programmes that divert from the WHO guidelines and their implication on drug resistance
Detection of Coulomb Charging around an Antidot
We have detected oscillations of the charge around a potential hill (antidot)
in a two-dimensional electron gas as a function of a perpendicular magnetic
field B. The field confines electrons around the antidot in closed orbits, the
areas of which are quantised through the Aharonov-Bohm effect. Increasing B
reduces each state's area, pushing electrons closer to the centre, until enough
charge builds up for an electron to tunnel out. This is a new form of the
Coulomb blockade seen in electrostatically confined dots. We have also studied
h/2e oscillations and found evidence for coupling of opposite spin states of
the lowest Landau level.Comment: 3 pages, 3 Postscript figures, submitted to the proceedings of
EP2DS-1
Dynamics of Learning with Restricted Training Sets I: General Theory
We study the dynamics of supervised learning in layered neural networks, in
the regime where the size of the training set is proportional to the number
of inputs. Here the local fields are no longer described by Gaussian
probability distributions and the learning dynamics is of a spin-glass nature,
with the composition of the training set playing the role of quenched disorder.
We show how dynamical replica theory can be used to predict the evolution of
macroscopic observables, including the two relevant performance measures
(training error and generalization error), incorporating the old formalism
developed for complete training sets in the limit as a
special case. For simplicity we restrict ourselves in this paper to
single-layer networks and realizable tasks.Comment: 39 pages, LaTe
Wind-tunnel calibration of a combined pitot-static tube and vane-type flow-angularity indicator at Mach numbers of 1.61 and 2.01
A limited calibration of a combined pitot-static tube and vane-type flow-angularity indicator has been made in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.61 and 2.01. The results indicated that the angle-of-yaw indications were affected by unsymmetric shock effects at low angles of attack
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