558 research outputs found
Modelling the effect of environmental variables on the reproductive success of Griffon Vulture (Gyps fulvus) in Sardinia, Italy
Old World vultures are experiencing dramatic population declines and now are among
the species most threatened with extinction. Understanding the environmental variables
that can influence the reproductive indexes of vulture populations can facilitate both
habitat and species management. The aim of this study was to identify which environmental
variables primarily affect the breeding successes of the Griffon Vulture Gyps fulvus
in northern Sardinia by applying a Bayesian hierarchical model. A unique dataset of
reproductive records (197 nests monitored over 39 years for a total of 992 breeding
records) was used. Eight environmental and topographical variables describing the habitat
at the nesting sites were considered as potential predictors of breeding success. These
included mean annual temperature, mean annual precipitation, isothermality, elevation,
the normalized difference vegetation index, wind speed, and the aspect and slope of the
land surface. In addition, we also considered the effect of human disturbance and the
type of nest. According to our best model, the probability of successfully raising a chick
in Griffon Vultures was higher in nests exposed to a high wind speed, not covered by
natural shelters, where the vegetation was mostly represented by shrub and pastures,
with low human disturbance and in years with low rainfall. This model will be useful for
management of the breeding habitat and to identify the area most suitable for Griffon
Vulture reproduction. This information is crucial for programming conservation measures
aimed at enlarging the area of occupancy of the species.Postprin
A ROBUST CONDENSATION STRATEGY FOR STOCHASTIC DYNAMIC SYSTEMS
In traditional design of engineering systems, it is normally assumed the mean values of the physical and mechanical properties. However, in real-world applications it may not characterize with reasonable accuracy the modifications on the dynamic behavior of the resulting systems induced by small changes on their design variables. Thus, it is interesting to perform a stochastic modeling strategy in order to take into account the presence of uncertainties. However, the stochastic finite element modeling of a more complex engineering structure composed by a large number of degrees of freedom, or its use in dynamic analyses requiring several evaluations such as in optimization and model updating, the computational cost can be prohibited or sometimes unfeasible. In these situations, the proposition of condensation strategy especially adapted for the resulting stochastic systems is interesting. This paper is devoted to the investigation of a robust model condensation strategy to reduce the random matrices of the stochastic system. The basis to be used is formed by a nominal basis evaluated by performing firstly an eigenvalue problem of the mean model enriched by static residues due to the small modifications introduced. To illustrate the main features and capabilities of the proposed strategy, numerical simulations were performed for a plate model in which the stochastic mass and stiffness matrices were generated by applying the so-called Karhunen-LoĂšve expansion. The stochastic results are presented in terms frequency response function envelopes for the full and reduced stochastic dynamic systems subjected to a deterministic excitation
Coordinated response to imported vaccine-derived poliovirus infection, Barcelona, Spain, 2019-2020
In 2019, the Public Health Agency of Barcelona, Spain, was notifi ed of a vaccine-derived poliovirus infection. The patient had an underlying common variable immunodefi ciency and no signs of acute fl accid paralysis. We describe the ongoing coordinated response to contain the infection, which included compassionate-use treatment with pocapavir
Leading order analysis of neutrino induced dimuon events in the CHORUS experiment
We present a leading order QCD analysis of a sample of neutrino induced
charged-current events with two muons in the final state originating in the
lead-scintillating fibre calorimeter of the CHORUS detector. The results are
based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign
dimuon events collected during the exposure of the detector to the CERN Wide
Band Neutrino Beam between 1995 and 1998. % with GeV
and GeV collected %between 1995 and 1998. The analysis yields a
value of the charm quark mass of \mc = (1.26\pm 0.16 \pm 0.09) \GeVcc and a
value of the ratio of the strange to non-strange sea in the nucleon of , improving the results obtained in similar analyses
by previous experiments.Comment: Submitted to Nuclear Physics
Associated Charm Production in Neutrino-Nucleus Interactions
In this paper a search for associated charm production both in neutral and
charged current -nucleus interactions is presented. The improvement of
automatic scanning systems in the {CHORUS} experiment allows an efficient
search to be performed in emulsion for short-lived particles. Hence a search
for rare processes, like the associated charm production, becomes possible
through the observation of the double charm-decay topology with a very low
background. About 130,000 interactions located in the emulsion target
have been analysed. Three events with two charm decays have been observed in
the neutral-current sample with an estimated background of 0.180.05. The
relative rate of the associated charm cross-section in deep inelastic
interactions, has been
measured. One event with two charm decays has been observed in charged-current
interactions with an estimated background of 0.180.06 and the
upper limit on associated charm production in charged-current interactions at
90% C.L. has been found to be .Comment: 10 pages, 4 figure
Charged-Particle Multiplicities in Charged-Current Neutrino-- and Anti-Neutrino--Nucleus Interactions
The CHORUS experiment, designed to search for
oscillations, consists of a nuclear emulsion target and electronic detectors.
In this paper, results on the production of charged particles in a small sample
of charged-current neutrino-- and anti-neutrino--nucleus interactions at high
energy are presented. For each event, the emission angle and the ionization
features of the charged particles produced in the interaction are recorded,
while the standard kinematic variables are reconstructed using the electronic
detectors. The average multiplicities for charged tracks, the pseudo-rapidity
distributions, the dispersion in the multiplicity of charged particles and the
KNO scaling are studied in different kinematical regions. A study of
quasi-elastic topologies performed for the first time in nuclear emulsions is
also reported. The results are presented in a form suitable for use in the
validation of Monte Carlo generators of neutrino--nucleus interactions.Comment: 17 pages, 5 figure
Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower
The results of the analysis of the data collected with the NEMO Phase-2
tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are
presented. Cherenkov photons detected with the photomultipliers tubes were used
to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution
was measured and the results compared with Monte Carlo simulations. An
evaluation of the systematic effects due to uncertainties on environmental and
detector parameters is also included. The associated depth intensity relation
was evaluated and compared with previous measurements and theoretical
predictions. With the present analysis, the muon depth intensity relation has
been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic
Quantification of milk adulterants (starch, H2O2, and NaClO) using colorimetric assays coupled to smartphone image analysis
In this paper, a colorimetric method for the detection of milk adulterants using smartphone image analysis is reported. This is based on the reactions to detect hydrogen peroxide, sodium hypochlorite, and starch in milk, where a color variation is observed for each substance. The image analysis was performed by using lab-made apps (PhotoMetrixÂź, and RedGIMÂź) based on partial least squares regression with the histograms of the red-green-blue images. The image histograms are automatically calculated using the smartphone camera and processed within the app. The results have shown the capability of this method to predict the concentration of the three adulterants, demonstrating the potential of the use of digital images and smartphone applications associated with chemometric tools. This method presents a fast, low-cost, and portable way to quantify adulterants in Cow milk
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