576 research outputs found
Winter activity of a population of greater horseshoe bats (Rhinolophus ferrumequinum)
Activity patterns of a greater horseshoe bats Rhinolophus ferrumequinum were investigated at caves in Cheddar (south-west England) during the hibernation season. An ultrasound detector and datalogger were used to monitor and record the number of echolocation calls in a single cave. Activity of R. ferrumequinum remained largely nocturnal throughout winter, and the mean time of activity over 24 hours was 88 to 369 minutes (1.47 to 6.15 hours) after sunset. There was an increase in diurnal activity from late May to early June, probably because bats remained active after foraging at dawn towards the end of the hibernation season. Visits to the cave did not increase bat activity. Cave air temperature reflected external climatic temperature, although there was variation in cave temperature and its range within and across caves. Individual R. ferrumequinum are usually dispersed in caves in regions where temperature fluctuations correlate with climatic variations in temperature. There was a positive correlation between the number of daily bat passes monitored by the bat detector and datalogger (= daily activity) and cave temperature. Nocturnal activity may sometimes be associated with winter feeding. Neither date nor barometric pressure had a significant effect on daily activity. Activity patterns largely reflected the findings from individual R. ferrumequinum studied by telemetry (Park, 1998), in that bat activity increased with cave and climatic temperatures, and the temporal pattern of activity remained consistently nocturnal throughout winter, starting at dusk
Torpor, arousal and activity of hibernating greater horseshoe bats (Rhinolophus ferrumequinum)
1. Patterns of torpor, arousal, and activity in free-living greater horseshoe bats, Rhinolophus ferrumequinum, were investigated during the hibernation period by using temperature-sensitive radio-transmitters. 2. Torpor bouts varied between 0.1 - 11.8 days, with individual means ranging from 1.3 - 7.4 days. Torpor bout duration decreased with increasing ambient temperature. 3. Activity duration varied from 37 minutes – 54 hours 24 minutes, with individual means ranging from 2:29 to 8:58 hours. Activity duration increased with ambient temperatures above approximately 10oC. 4. Ten of 11 bats synchronised their arousals with dusk. The circadian rhythm of one bat showed a free-running pattern over a period of about five weeks. Arousals were more highly synchronised, and closer to dusk, in individuals with lower body condition. 5. That bats forage in mild weather is supported by the strong synchronisation of arousals with dusk, especially in bats with low body condition. 6. Patterns of torpor and subsequent activity are consistent with predictions that torpor lasts until a critical metabolic or water imbalance is achieved. Because metabolism and water loss are temperature-dependent, torpor bout duration decreases with increasing temperature. The imbalance is corrected during subsequent activity, which is relatively constant in duration until a temperature threshold of 10oC, above which increasing levels of foraging lead to longer activity bouts
Single neutral pion production by charged-current (nu)over-bar(mu) interactions on hydrocarbon at \u3c E-nu \u3e=3.6 GeV
Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the MINERvA detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for (nu) over bar (e) appearance oscillation experiments. The differential cross sections for pi(0) momentum and production angle, for events with single observed pi(0) and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the pi(0) kinematics for this process. (C) 2015 The Authors. Published by Elsevier B.V
Reducing model bias in a deep learning classifier using domain adversarial neural networks in the MINERvA experiment
We present a simulation-based study using deep convolutional neural networks
(DCNNs) to identify neutrino interaction vertices in the MINERvA passive
targets region, and illustrate the application of domain adversarial neural
networks (DANNs) in this context. DANNs are designed to be trained in one
domain (simulated data) but tested in a second domain (physics data) and
utilize unlabeled data from the second domain so that during training only
features which are unable to discriminate between the domains are promoted.
MINERvA is a neutrino-nucleus scattering experiment using the NuMI beamline at
Fermilab. -dependent cross sections are an important part of the physics
program, and these measurements require vertex finding in complicated events.
To illustrate the impact of the DANN we used a modified set of simulation in
place of physics data during the training of the DANN and then used the label
of the modified simulation during the evaluation of the DANN. We find that deep
learning based methods offer significant advantages over our prior track-based
reconstruction for the task of vertex finding, and that DANNs are able to
improve the performance of deep networks by leveraging available unlabeled data
and by mitigating network performance degradation rooted in biases in the
physics models used for training.Comment: 41 page
Organization theory and military metaphor: time for a reappraisal?
A ‘conventional’ use of military metaphor would use it to convey attributes such as hierarchical organization, vertical communication and limited autonomy. This is often used in contrast to a looser form of organization based on the metaphor of the network. However, this article argues that military practice is more complex, with examples of considerable autonomy within the constraints of central direction. It is suggested that not only might this be a more useful metaphor for many contemporary organizations, but also that simplistic uses of military metaphor divert our attention away from the functions that management hierarchies play. The discussion is embedded within a critical realist account of metaphor, arguing for both its value and the need for its further development
Polarization transfer in the HeH reaction
Polarization transfer in the 4He(e,e'p)3H reaction at a Q^2 of 0.4 (GeV/c)^2
was measured at the Mainz Microtron MAMI. The ratio of the transverse to the
longitudinal polarization components of the ejected protons was compared with
the same ratio for elastic ep scattering. The results are consistent with a
recent fully relativistic calculation which includes a predicted medium
modification of the proton form factor based on a quark-meson coupling model.Comment: 5 pages, Latex, 2 postscript figures, submitted to Physics Letters
Measurement of the recoil polarization in the p (\vec e, e' \vec p) pi^0 reaction at the \Delta(1232) resonance
The recoil proton polarization has been measured in the p (\vec e,e'\vec p)
pi^0 reaction in parallel kinematics around W = 1232 MeV, Q^2 = 0.121 (GeV/c)^2
and epsilon = 0.718 using the polarized c.w. electron beam of the Mainz
Microtron. Due to the spin precession in a magnetic spectrometer, all three
proton polarization components P_x/P_e = (-11.4 \pm 1.3 \pm 1.4) %, P_y =
(-43.1 \pm 1.3 \pm 2.2) %, and P_z/P_e = (56.2 \pm 1.5 \pm 2.6) % could be
measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio CMR =
(-6.4\pm 0.7_{stat}\pm 0.8_{syst}) % was determined from P_x in the framework
of the Mainz Unitary Isobar Model. The consistency among the reduced
polarizations and the extraction of the ratio of longitudinal to transverse
response is discussed.Comment: 5 pages LaTeX, 1 table, 2 eps figure
A precise extraction of the induced polarization in the 4He(e,e'p)3H reaction
We measured with unprecedented precision the induced polarization Py in
4He(e,e'p)3H at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2. The induced polarization
is indicative of reaction-mechanism effects beyond the impulse approximation.
Our results are in agreement with a relativistic distorted-wave impulse
approximation calculation but are over-estimated by a calculation with strong
charge-exchange effects. Our data are used to constrain the strength of the
spin independent charge-exchange term in the latter calculation.Comment: submitted to Physical Review Letter
Polarization Transfer in the 4He(e,e'p)3H Reaction at Q^2 = 0.8 and 1.3 (GeV/c)^2
Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H
reaction at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2 with unprecedented precision.
The polarization-transfer coefficients are found to differ from those of the
1H(e,e' p) reaction, contradicting a relativistic distorted-wave approximation,
and favoring either the inclusion of medium-modified proton form factors
predicted by the quark-meson coupling model or a spin-dependent charge-exchange
final-state interaction. For the first time, the polarization-transfer ratio is
studied as a function of the virtuality of the proton
The MINERA Data Acquisition System and Infrastructure
MINERA (Main INjector ExpeRiment -A) is a new few-GeV neutrino
cross section experiment that began taking data in the FNAL NuMI (Fermi
National Accelerator Laboratory Neutrinos at the Main Injector) beam-line in
March of 2010. MINERA employs a fine-grained scintillator detector capable
of complete kinematic characterization of neutrino interactions. This paper
describes the MINERA data acquisition system (DAQ) including the read-out
electronics, software, and computing architecture.Comment: 34 pages, 16 figure
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