874 research outputs found
CP violation in 5D Split Fermions Scenario
We give a new configuration of split fermion positions in one extra dimension
with two different Yukawa coupling strengths for up-type, , and down-type,
, quarks at . The new configurations can give enough
CP violating (CPV) phase for accommodating all currently observed CPV
processes. Therefore, a 5D standard model with split fermions is viable. In
addition to the standard CKM phase, new CPV sources involving Kaluza-Klein(KK)
gauge bosons coupling which arise from the fact that unitary rotation which
transforms weak eigenstates into their mass eigenstates only holds for the zero
modes which are the SM fields and not for the KK excitations. We have examined
the physics of kaon, neutron, and mesons and found the most stringent
bound on the size of the extra dimension comes from .
Moreover, it depends sensitively on the width, , of the Gaussian
wavefunction in the extra dimension used to describe of the fermions. When
, the constraint will be lifted due to GIM suppression on the
flavor changing neutral current(FCNC) and CPV couplings.Comment: 24 pages, 8 figure
Dynamic Capabilities in Media Management Research: A Literature Review
Abstract Purpose – This study explores Dynamic Capabilities (DC) as one of the most prolific streams of research within the field of management and looks its applicability for media management research. Argumentation – It argues that reviewing the lineages of DC is a useful exercise for answering questions surrounding the fundamental change in the media industry, the challenges that media organizations and their managers are currently facing under the impact of digital change, and the theoretical grounding DC offers for media management scholars in understand the breadth and complexity of these challenges. Design/Methodology/Approach – This study uses a systematic reviewing methodology on DC in media management research. Findings – The study shows that DC help media research understand how media firms can best respond to changing environments. Research activity published from 2003 to 2019 in the field of media management has grown considerably. In the number of research papers related to the dynamic capabilities concept in the media management field between. Originality/Value – The study qualifies the validity of the DC framework in media management research and discusses conceptual bridges between the fields, its constituencies and perspectives
Estimation of the Direct Cost of HIV-Infected Patients in Greece on an Annual Basis
AbstractObjectiveHIV infection is currently regarded as a global chronic disease. The purpose of this study was to assess the direct cost of illness per patient per year in Greece.MethodsA retrospective study for the estimation of the direct cost of HIV infection was performed from the third-party payer perspective. Data from 447 patients monitored in a general hospital of Athens were collected from their medical records. The survey involved all services and treatments that patients (stratified into three health states according to the number of CD4 cells/ml as defined by the Centers for Disease Control and Prevention classification system for HIV infection) received in 1 year, as well as demographic data.ResultsThe annual direct cost per patient was calculated at €6859 ± €4699. Antiretroviral therapy cost was estimated at €5741, while the annual cost of providing health care services regardless of health state was computed at €1118, with laboratory investigation and imaging studies representing €924 (13.5%), outpatient visits €34 (0.5%), and hospitalization €160 (2.3%) of total cost, respectively. Overall, direct cost per patient was found to increase as the CD4 T lymphocytes decreased, leading to prolonged hospitalization and an increase in the number of laboratory tests. Direct cost for patients with more than 500 CD4 cells/μl was estimated at €6067, whereas for those with 200 to 499 cells/μl and less than 200 cells/μl, it was assessed at €6857 and €7654, respectively.ConclusionsThe direct cost of HIV infection per patient increased as CD4 T lymphocytes decreased. The largest part of expenses was attributed to antiretroviral therapy, followed by laboratory tests/imaging studies, hospitalization, and finally outpatient visits
Sustainable small ruminant breeding program for climate-smart villages in Kenya
Improving productivity of sheep and goats (i.e. small ruminants- SR) under smallholder
farming systems faced with challenges of unfavourable climatic events has been identified as
one means of enhancing livelihoods of communities living in these areas. Interventions are
targeted through clusters of farmers grouped into “climate smart villages” (CSV) under a
collaborative action by CCAFS, ViAgroforestry, World Neighbours and the Kenya
Agricultural and Livestock Research Organization. This baseline study was implemented to
understand the socio-economic aspects, population structure, management practices and
production constraints of SR in the CSV of the Lower Nyando basin of Kenya. The results
indicate that the community is mainly comprised of young people (mainly students) and men
and women above 50 years of age who manage the various households. Land sizes owned are
small, with 58% of the households owning less than one hectare of land on which they grow
crops and rear on average eight SR in addition to some cattle and poultry. The SR reared are
mainly indigenous breeds, with some crossbreds resulting from the few introduced Red
Maasai sheep and the Galla goats for improved productivity. Breeding of SR is not controlled,
and since larger animals fetch better prices on the market, over time negative selection has
affected the SR population. SR are generally left to graze on stovers from crops, and take a
long time to grow to maturity (up to 4 years). Farmers in the CSV know what traits they
desire in their SR, and are willing to learn and change their practices in order to improve their
livelihoods. It is evident that the organization of the households into CSVs provides a great
opportunity for capacity development which should have a strong component of engaging the
youth, and the development of a selection and breed improvement program for SR in the
Lower Nyando area
A numerical study of multi-soliton configurations in a doped antiferromagnetic Mott insulator
We evaluate from first principles the self-consistent Hartree-Fock energies
for multi-soliton configurations in a doped, spin-1/2, antiferromagnetic Mott
insulator on a two-dimensional square lattice. We find that nearest-neighbor
Coulomb repulsion stabilizes a regime of charged meron-antimeron vortex soliton
pairs over a region of doping from 0.05 to 0.4 holes per site for intermediate
coupling 3 < U/t <8. This stabilization is mediated through the generation of
``spin-flux'' in the mean-field antiferromagnetic (AFM) background. Holes
cloaked by a meron-vortex in the spin-flux AFM background are charged bosons.
Our static Hartree-Fock calculations provide an upper bound on the energy of a
finite density of charged vortices. This upper bound is lower than the energy
of the corresponding charged stripe configurations. A finite density of charge
carrying vortices is shown to produce a large number of unoccupied electronic
levels in the Mott-Hubbard charge transfer gap. These levels lead to
significant band tailing and a broad mid-infrared band in the optical
absorption spectrum as observed experimentally. At very low doping (below 0.05)
the doping charges create extremely tightly bound meron-antimeron pairs or even
isolated conventional spin-polarons, whereas for very high doping (above 0.4)
the spin background itself becomes unstable to formation of a conventional
Fermi liquid and the spin-flux mean-field is energetically unfavorable. Our
results point to the predominance of a quantum liquid of charged, bosonic,
vortex solitons at intermediate coupling and intermediate doping
concentrations.Comment: 12 pages, 25 figures; added references, modified/eliminated some
figure
System characteristics and management practices for small ruminant production in “Climate Smart Villages” of Kenya
The CGIAR research programme on Climate Change Agriculture and Food Security, in collaboration with several partners is testing a portfolio of interventions to address the threat of changing climatic conditions for smallholder farming communities living beside river flood plains, grouped into “Climate Smart Villages” (CSVs). We present characteristics of farms in CSV in relation to small ruminant (SR) production and the scenario for a breeding and improvement programme. Information was collated using participatory systems research methods from 140 households in seven CSVs in Nyando basin, Kenya. Although most households were headed by men, there were a higher proportion of adult women within the communities, and literacy levels were moderate. A total of 58 percent of the population owned <1 ha of land for growing crops and rearing on average 6.96 ± 3.35 Tropical Livestock Units comprising different species of animals. Women headed households owned more sheep which were mainly crosses of unspecified local breeds, than Goats which were mainly the Small East African breed-type. Mating among the SR was random, with no control of inbreeding as flocks mixed in grazing fields and at water points. Farmers desired large and resilient animals for better market prices; however, growth rates were slow. The SR flocks were dynamic with 31 percent of the animals moving in and out of flocks in a year. A community breeding programme optimally using available resources and incorporating gender integrated innovative technologies could be implemented for the CSV, alongside strong capacity development on animal husbandry, health and marketing of products
An Invitation to Higher Gauge Theory
In this easy introduction to higher gauge theory, we describe parallel
transport for particles and strings in terms of 2-connections on 2-bundles.
Just as ordinary gauge theory involves a gauge group, this generalization
involves a gauge '2-group'. We focus on 6 examples. First, every abelian Lie
group gives a Lie 2-group; the case of U(1) yields the theory of U(1) gerbes,
which play an important role in string theory and multisymplectic geometry.
Second, every group representation gives a Lie 2-group; the representation of
the Lorentz group on 4d Minkowski spacetime gives the Poincar\'e 2-group, which
leads to a spin foam model for Minkowski spacetime. Third, taking the adjoint
representation of any Lie group on its own Lie algebra gives a 'tangent
2-group', which serves as a gauge 2-group in 4d BF theory, which has
topological gravity as a special case. Fourth, every Lie group has an 'inner
automorphism 2-group', which serves as the gauge group in 4d BF theory with
cosmological constant term. Fifth, every Lie group has an 'automorphism
2-group', which plays an important role in the theory of nonabelian gerbes. And
sixth, every compact simple Lie group gives a 'string 2-group'. We also touch
upon higher structures such as the 'gravity 3-group' and the Lie 3-superalgebra
that governs 11-dimensional supergravity.Comment: 60 pages, based on lectures at the 2nd School and Workshop on Quantum
Gravity and Quantum Geometry at the 2009 Corfu Summer Institut
A novel use of high density SNP assays to optimize choice of different crossbred dairy cattle genotypes in smallholder systems in East Africa
We present use of SNP technologies to obtain for the first time, rapid, large-scale, in situ estimates of performance of crossbred cows in smallholder herds. Compared to historical approaches, our approach allowed optimum crossbreed choices to be determined more rapidly and without question about the relevance of the environment. High-density SNP assays were used to estimate breed composition for a monitored population comprising 1292 cows from 610 smallholder farms in Kenya. The achieved milk yields are much lower than generally assumed and lactation curves are very flat out to 400 days. In poor production environments, lower grade crosses (containing <60% exotic dairy alleles) had the same yield as high grade crosses. Allowing for the larger size and maintenance requirements of high grade exotics, lower grade exotics will be the most economically productive animals in these environments
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