4,951 research outputs found
Mock Catalogs for UHECR Studies
We provide realistic mock-catalogs of cosmic rays above 40 EeV, for a pure
proton composition, assuming their sources are a random subset of ordinary
galaxies in a simulated, volume-limited survey, for various choices of source
density: 10^-3.5 Mpc^-3, 10^-4.0 Mpc^-3 and 10^-4.5 Mpc^-3. The spectrum at the
source is taken to be E^-2.3 and the effects of cosmological redshifting as
well as photo-pion and e^+ e^- energy losses are included.Comment: 7 pages, 4 figure
Effective CP violation in the Standard Model
We study the strength of effective CP violation originating from the CKM
matrix in the effective action obtained by integrating out the fermions in the
Standard Model. Using results obtained by Salcedo for the effective action in a
general chiral gauge model, we find that there are no CKM CP-violating terms to
fourth order in a gauge-covariant derivative expansion that is non-perturbative
in the Higgs field. The details of the calculation suggest that, at zero
temperature, the strength of CP violation is approximately independent of the
overall scale of the Yukawa couplings. Thus, order of magnitude estimates based
on Jarlskog's invariant could be too small by a factor of about 10^{17}.Comment: 19 pages, no figure
Correction to “Intraseasonal variability near 10°N in the eastern tropical Pacific Ocean”
Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): C03011, doi:10.1029/2007JC004135
An Investigation of the Character Traits of Decision-Makers Open to Intuition as a Tool
The increasing complexity of business environments has resulted in decision-making also becoming more complicated. While classical decision-making theories purport strategic decision-making to be a result of rational contemplation, more recent research findings have put forward a more holistic view, which includes intuition as a tool for decision-making processes. Studies illustrate, that the implementation of intuition as a part of decision-making in companies can lead to improved company performance. Dealing with decisions and the way decisions are made is very individual and according to Musso and Francioni (2012) is mostly influenced by the decision maker’s personality. Traditionally, there has been a differentiation made between decision-makers that employ a rational method of decision-making and those that use intuition. Successful decision-makers appear to be able to commingle both of these decision-making methods and it is the character traits of precisely these decision-makers which will be scrutinized. The aim of this paper is to discuss the personality of the decision-maker who is open to intuition
Moored surface buoy observations of the diurnal warm layer
Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 4553–4569, doi:10.1002/jgrc.20360.An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5–15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models.J.P. was supported
for part of this work by a graduate exchange studentship from the
Graduate School of the National Oceanography Centre, Southampton.
J.T.F. was supported by NSF OCE Award 0745508, the Charles D. Hollister
Fund for Assistant Scientist Support, and the John E. and Anne W.
Sawyer Endowed Fund in Special Support of Scientific Staff. R.A.W. was
supported by the Office of Naval Research for the deployment of the Arabian
Sea surface mooring, and by the NOAA Climate Program and Climate
Observation Division for the deployment of the PACS and Stratus
surface moorings. J.T.F. was supported under a cooperative program
between WHOI and King Abdullah University of Science and Technology
(KAUST; Awards USA00001, USA00002, and KSA00011) of the Kingdom
of Saudi Arabia for the deployment of the KAUST surface moorings.2014-03-1
CBLAST 2003 field work report
The long-range scientific objective of the Coupled Boundary Layer Air Sea Transfer
(CBLAST) project is to observe and understand the temporal and spatial variability of the
upper ocean, to identify the processes that determine that variability, and to examine its
predictability. Air-sea interaction is of particular interest, but attention is also paid to the
coupling of the sub-thermocline ocean to the mixed layer and to both the open ocean and
littoral regimes. We seek to do this over a wide range of environmental conditions with
the intent of improving our understanding of upper ocean dynamics and of the physical
processes that determine the vertical and horizontal structure of the upper ocean.
Field work for CBLAST was conducted during the summers of 2001, 2002, and 2003 off
the south shore of Martha’s Vineyard, Massachusetts. The 2003 field work was conducted
from the following platforms: heavy moorings, light moorings, drifters, F/V Nobska,
CIRPAS Pelican aircraft, and an IR Cessna Aircraft. This report documents the 2003 field
work and includes field notes, platform descriptions, discussion of data returns, and
mooring logs. The 2003 Intensive Operating Period (IOP) was very successful and a high
data return was seen.Funding was provided by the Office of Naval Research under contract numbers
N00014-01-1-0029 and N00014-05-10090
Hadron Helicity Violation in Exclusive Processes: Quantitative Calculations in Leading Order QCD
We study a new mechanism for hadronic helicity flip in high energy hard
exclusive reactions. The mechanism proceeds in the limit of perfect chiral
symmetry, namely without any need to flip a quark helicity. The fundamental
feature of the new mechanism is the breaking of rotational symmetry of the hard
collision by a scattering plane in processes involving independent quark
scattering. We show that in the impulse approximation there is no evidence for
of the helicity violating process as the energy or momentum transfer is
increased over the region 1 GeV^2 < Q^2 < 100 GeV^2. In the asymptotic region
Q^2> 1000 GeV^2, a saddle point approximation with doubly logarithmic accuracy
yields suppression by a fraction of power of Q^2. ``Chirally--odd" exclusive
wave functions which carry non--zero orbital angular momentum and yet are
leading order in the high energy limit, play an important role.Comment: uuencoded LaTeX file (21 pages) and PostScript figure
Statistical Matrix for Electroweak Baryogenesis
In electroweak baryogenesis, a domain wall between the spontaneously broken
and unbroken phases acts as a separator of baryon (or lepton) number,
generating a baryon asymmetry in the universe. If the wall is thin relative to
plasma mean free paths, one computes baryon current into the broken phase by
determining the quantum mechanical transmission of plasma components in the
potential of the spatially changing Higgs VEV. We show that baryon current can
also be obtained using a statistical density operator. This new formulation of
the problem provides a consistent framework for studying the influence of
quasiparticle lifetimes on baryon current. We show that when the plasma has no
self-interactions, familiar results are reproduced. When plasma
self-interactions are included, the baryon current into the broken phase is
related to an imaginary time temperature Green's function.Comment: 20 pages, no figures, Late
Interacting Dark Matter and Dark Energy
We discuss models for the cosmological dark sector in which the energy
density of a scalar field approximates Einstein's cosmological constant and the
scalar field value determines the dark matter particle mass by a Yukawa
coupling. A model with one dark matter family can be adjusted so the
observational constraints on the cosmological parameters are close to but
different from what is predicted by the Lambda CDM model. This may be a useful
aid to judging how tightly the cosmological parameters are constrained by the
new generation of cosmological tests that depend on the theory of structure
formation. In a model with two families of dark matter particles the scalar
field may be locked to near zero mass for one family. This can suppress the
long-range scalar force in the dark sector and eliminate evolution of the
effective cosmological constant and the mass of the nonrelativistic dark matter
particles, making the model close to Lambda CDM, until the particle number
density becomes low enough to allow the scalar field to evolve. This is a
useful example of the possibility for complexity in the dark sector.Comment: 15 pages, 6 figures; added a reference and a minor correctio
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