2,678 research outputs found
Asymptotics and local constancy of characters of p-adic groups
In this paper we study quantitative aspects of trace characters
of reductive -adic groups when the representation varies. Our approach
is based on the local constancy of characters and we survey some other related
results. We formulate a conjecture on the behavior of relative to
the formal degree of , which we are able to prove in the case where
is a tame supercuspidal. The proof builds on J.-K.~Yu's construction and the
structure of Moy-Prasad subgroups.Comment: Proceedings of Simons symposium on the trace formul
Dust detection by the wave instrument on STEREO: nanoparticles picked up by the solar wind?
The STEREO/WAVES instrument has detected a very large number of intense
voltage pulses. We suggest that these events are produced by impact ionisation
of nanoparticles striking the spacecraft at a velocity of the order of
magnitude of the solar wind speed. Nanoparticles, which are half-way between
micron-sized dust and atomic ions, have such a large charge-to-mass ratio that
the electric field induced by the solar wind magnetic field accelerates them
very efficiently. Since the voltage produced by dust impacts increases very
fast with speed, such nanoparticles produce signals as high as do much larger
grains of smaller speeds. The flux of 10-nm radius grains inferred in this way
is compatible with the interplanetary dust flux model. The present results may
represent the first detection of fast nanoparticles in interplanetary space
near Earth orbit.Comment: In press in Solar Physics, 13 pages, 5 figure
The association between calf circumference and appendicular skeletal muscle mass index of black urban women in Tlokwe City
Background: Sarcopenia, the loss of muscle mass and strength, is associated with adverse health outcomes. Calf circumference (CC) has been proposed as a surrogate measure of muscle mass in the elderly; however, ethnic/sex specific cut-off values remain to be established.Objective: A study was undertaken to investigate the relationship between CC and appendicular skeletal muscle mass (ASM), and the ASM index (ASMI), as well as to determine whether CC could be used to diagnose sarcopenia.Methods: This was a cross-sectional study of 247 older black women living from Tlokwe, South Africa. ASM was measured using dual-energy X-ray absorptiometry, and the ASMI was calculated. Receiver operator characteristics curves and maximum Youden index were applied to identify a CC cut-off point for sarcopenia according to low gait speed (< 0.8 m/s), low hand-grip strength (< 16 kg) and low ASMI using a South African cut-off point for sarcopenia (ASMI < 4.94 kg/m2).Results: A strong positive correlation between CC and ASMI (r = 0.84, p < 0.001) was observed. The CC to predict low hand-grip strength was 34.3 cm and 37.8 cm for low gait speed. A CC of 29.9 cm was indicative of sarcopenia. The area under the curve for all outcomes was > 0.60.Conclusion: A CC of 30 cm is proposed as a simple and inexpensive way to predict, screen or diagnose sarcopenia in black women in low-resource health settings. An accessible, inexpensive screening or diagnostic tool could facilitate timely interventions and prevention.Keywords: gait speed, geriatric, hand-grip strength, muscle strength, sarcopeni
Radiative Capture of Tensor Polarized Deuterons on Hydrogen Isotopes
This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440
Dynamics of Phase Transitions by Hysteresis Methods I
In studies of the QCD deconfining phase transition or crossover by means of
heavy ion experiments, one ought to be concerned about non-equilibrium effects
due to heating and cooling of the system. Motivated by this, we look at
hysteresis methods to study the dynamics of phase transitions. Our systems are
temperature driven through the phase transition using updating procedures in
the Glauber universality class. Hysteresis calculations are presented for a
number of observables, including the (internal) energy, properties of
Fortuin-Kasteleyn clusters and structure functions. We test the methods for 2d
Potts models, which provide a rich collection of phase transitions with a
number of rigorously known properties. Comparing with equilibrium
configurations we find a scenario where the dynamics of the transition leads to
a spinodal decomposition which dominates the statistical properties of the
configurations. One may expect an enhancement of low energy gluon production
due to spinodal decomposition of the Polyakov loops, if such a scenario is
realized by nature.Comment: 12 pages, revised after referee report, to appear in Phys. Rev.
Seasonality of the Mediterranean fruit fly (Diptera: Tephritidae) on Terceira and São Jorge islands, Azores, Portugal
Research ArticlePopulation dynamics studies are very important for any area-wide control program as they provide detailed
knowledge about the relationship of Medfly [Ceratitis capitata (Wiedemann)] life cycle with host availability and
abundance. The main goal of this study is to analyse seasonality of C. capitata in Terceira and Sao Jorge
Islands (Azores archipelago) using field and laboratory data collected during (2010–2014) CABMEDMAC (MAC/
3/A163) project. The results from Sao Jorge Island indicate significantly lower male/female ratio than on
Terceira Island. This is an important finding specially regarding when stablishing the scenario parameters for a
sterile insect technique application in each island. The population dynamics of C. capitata are generally linked
with host fruit availability and abundance. However, on Terceira Island fruit infestation levels are not synchronized
with the trap counts. For example, there was Medfly infestations in some fruits [e.g., Solanum mauritianum
(Scop.)] while in the nearby traps there were no captures at the same time. From this perspective, it is important
to denote the importance of wild invasive plants, on the population dynamics of C. capitata, as well
important to consider the possibility of having different densities of traps according to the characteristics of
each area in order to improve the network of traps surveillance’s sensitivity on Terceira Islandinfo:eu-repo/semantics/publishedVersio
Pairing correlations. Part 1: description of odd nuclei in mean-field theories
In order to extract informations on pairing correlations in nuclei from
experimental mass differences, the different contributions to odd-even mass
differences are investigated within the Skyrme HFB method. In this first paper,
the description of odd nuclei within HFB is discussed since it is the key point
for the understanding of the above mentioned contributions. To go from an even
nucleus to an odd one, the advantage of a two steps process is demonstrated and
its physical content is discussed. New results concerning time-reversal
symmetry breaking in odd-nuclei are also reported.
PACS: 21.10Dr; 21.10.Hw; 21.30.-x.
Keywords: Mean-field theories; Pairing correlations; odd nuclei;Comment: 34 pages, 8 figures. Submitted to Phys. Rev.
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Why Are People's Decisions Sometimes Worse with Computer Support?
In many applications of computerised decision support, a recognised source of undesired outcomes is operators' apparent over-reliance on automation. For instance, an operator may fail to react to a potentially dangerous situation because a computer fails to generate an alarm. However, the very use of terms like "over-reliance" betrays possible misunderstandings of these phenomena and their causes, which may lead to ineffective corrective action (e.g. training or procedures that do not counteract all the causes of the apparently "over-reliant" behaviour). We review relevant literature in the area of "automation bias" and describe the diverse mechanisms that may be involved in human errors when using computer support. We discuss these mechanisms, with reference to errors of omission when using "alerting systems", with the help of examples of novel counterintuitive findings we obtained from a case study in a health care application, as well as other examples from the literature
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