300 research outputs found
Monitoring Penguins at Sea using Data Loggers
The activity of four penguin species at sea was studied using new data loggers. One
unit was fixed to the bird's backs and recorded swim speed, swim heading and dive depth
from which the three dimensional movements of the birds at sea could be constructed by
vector calculations. This unit additionally recorded sea temperature and light intensity. A
further, single-channel logger was ingested by the birds and recorded stomach temperature
during the periods at sea. Drops in stomach temperature were indicative of prey
capture and could be ascribed to specific localities
On loss aversion in bimatrix games
ABSTRACT. In this article three different types of loss aversion equilibria in bimatrix games are studied. Loss aversion equilibria are Nash equilibria of games where players are loss averse and where the reference points-points below which they consider payoffs to be lossesare endogenous to the equilibrium calculation. The first type is the fixed point loss aversion equilibrium, introduced in Shalev (2000; Int. J. Game Theory 29(2):269) under the name of 'myopic loss aversion equilibrium.' There, the players' reference points depend on the beliefs about their opponents' strategies. The second type, the maximin loss aversion equilibrium, differs from the fixed point loss aversion equilibrium in that the reference points are only based on the carriers of the strategies, not on the exact probabilities. In the third type, the safety level loss aversion equilibrium, the reference points depend on the values of the own payoff matrices. Finally, a comparative statics analysis is carried out of all three equilibrium concepts in 2 × 2 bimatrix games. It is established when a player benefits from his opponent falsely believing that he is loss averse
The Higgs Boson Production Cross Section as a Precision Observable?
We investigate what can be learned at a linear collider about the sector of
electroweak symmetry breaking from a precise measurement of the Higgs boson
production cross section through the process e+e- -> hZ. We focus on deviations
from the Standard Model arising in its minimal supersymmetric extension. The
analysis is performed within two realistic future scenarios, taking into
account all prospective experimental errors on supersymmetric particle masses
as well as uncertainties from unknown higher order corrections. We find that
information on tan beta and M_A could be obtained from a cross section
measurement with a precision of 0.5 - 1 %. Alternatively, information could be
obtained on the gaugino mass parameters M_2 and mu if they are relatively
small, M_2, mu approximately 200 GeV.Comment: 13 pages, 3 figures. Discussion on experimental errors enlarged,
references added and updated. Version to appear in Phys. Rev.
Itinerant ferromagnetism mediated by giant spin polarization of metallic ligand band in van der Waals magnet Fe5GeTe2
We investigate near-Fermi-energy (EF) element-specific electronic and spin
states of ferromagnetic van der Waals (vdW) metal Fe5GeTe2. The soft x-ray
angle-resolved photoemission spectroscopy (SX-ARPES) measurement provides
spectroscopic evidence of localized Fe 3d band. We also find prominent
hybridization between the localized Fe 3d band and the delocalized Ge/Te p
bands. This picture is strongly supported from direct observation of the
remarkable spin polarization of the ligand p bands near EF, using x-ray
magnetic circular dichroism (XMCD) measurements. The strength of XMCD signal
from ligand element Te shows the highest value, as far as we recognize, among
literature reporting finite XMCD signal for none-magnetic element in any
systems. Combining SX-ARPES and elemental selective XMCD measurements, we
collectively point an important role of giant spin polarization of the
delocalized ligand Te states for realizing itinerant long-range ferromagnetism
in Fe5GeTe2. Our finding provides a fundamental elemental selective view-point
for understanding mechanism of itinerant ferromagnetism in low dimensional
compounds, which also leads insight for designing exotic magnetic states by
interfacial band engineering in heterostructures
The Clean Power Plan: Issues to Watch
Although the Clean Air Act is an imperfect tool for addressing the nation’s greenhouse gas emissions, it is the only available federal mechanism for directly addressing power plant carbon emissions. The Obama Administration’s Clean Power Plan, published in final form in August 2015, tackles the challenge. This paper from the Center for Progressive Reform (CPR) compiles 13 separately authored essays from 11 CPR Member Scholars, each addressing a different topic related to the Clean Power Plan, and each representing the expertise and views of its individual author(s). Published in July 2015, just before the release of the final rule, the essays tee up key questions about the rule’s legality, implications for the energy sector, and a series of discrete implementation questions, including the role of cap-and-trade (and offsets), the nature and distribution of state targets, and implications for environmental justice
The Higgs - photon - Z boson coupling revisited
We analyze the coupling of CP-even and CP-odd Higgs bosons to a photon and a
Z boson in extensions of the Standard Model. In particular, we study in detail
the effect of charged Higgs bosons in two-Higgs doublet models, and the
contribution of SUSY particle loops in the minimal supersymmetric extension of
the Standard Model. The Higgs- coupling can be measured in the decay
+Higgs at colliders running on the Z resonance, or in
the reverse process Higgs with the Higgs boson produced at LHC.
We show that a measurement of this coupling with a precision at the percent
level, which could be the case at future colliders, would allow to
distinguish between the lightest SUSY and standard Higgs bosons in large areas
of the parameter space.Comment: 18 pages LaTex + 7 figures (ps). Typo corrected in eq.(5
Color-Singlet Production at Colliders
We calculate in closed form the complete
color-singlet differential cross section for
scattering. The cross section reduces at high energies to a heavy quark
fragmentation form. We find that the energy scale at which the approximate
fragmentation result becomes reliable exceeds the mass by more than an
order of magnitude. We also discuss the color-singlet model's predictions for
direct angular and energy distributions at CLEO.Comment: 17 pages RevTeX, 5 embedded ps/eps figure
Analytic properties of the Landau gauge gluon and quark propagators
We explore the analytic structure of the gluon and quark propagators of
Landau gauge QCD from numerical solutions of the coupled system of renormalized
Dyson--Schwinger equations and from fits to lattice data. We find sizable
negative norm contributions in the transverse gluon propagator indicating the
absence of the transverse gluon from the physical spectrum. A simple analytic
structure for the gluon propagator is proposed. For the quark propagator we
find evidence for a mass-like singularity on the real timelike momentum axis,
with a mass of 350 to 500 MeV. Within the employed Green's functions approach
we identify a crucial term in the quark-gluon vertex that leads to a positive
definite Schwinger function for the quark propagator.Comment: 42 pages, 16 figures, revtex; version to be published in Phys Rev
Rethinking Sustainability to Meet the Climate Change Challenge
A group of environmental law professors formed the Environmental Law Collaborative with the goal of engaging environmental law scholars in the thorny issues of the day. The members of the Collaborative gathered in the summer of 2012 to produce an intensive and collective assessment of sustainability in the age of climate change. Their writings examine the process of adapting the principles and application of sustainability to the demands of climate change, including framing the term sustainability in climate change discussions; coordinating sustainable practices across disciplines such as law, economics, ethics, and the hard sciences; and conceptualizing the role of sustainability in formulating adaptation and resiliency strategies. Their work also contemplates the role of law and legal systems in crafting effective climate change adaptation strategies and considers feasible strategies in the context of specific examples
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