6,612 research outputs found
There Is No Special Problem About Scientific Representation
In recent years, philosophers of science have devoted considerable attention to questions about scientific models, and particularly to the issue of how models can represent the world. We propose that scientific representation is best understood as a special case of a more general notion of representation, and that the relatively well worked-out and plausible philosophical theories of the latter are directly applicable to the scientific special case. Construing scientific representation in this way makes the so-called ``problem of scientific representation'' look much less interesting than it has seemed to many, and also suggests that some of the (hotly contested) debates in the literature are concerned with non-issues
Gauge Mediated Mini-Split
We propose a simple model of split supersymmetry from gauge mediation. This
model features gauginos that are parametrically a loop factor lighter than
scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple
solution to the problem. The gaugino mass suppression can be
understood as resulting from collective symmetry breaking. Imposing collider
bounds on and requiring viable electroweak symmetry breaking implies
small -terms and small -- the stop mass ranges from to
10^8 \mbox{ GeV}. In contrast with models with anomaly + gravity mediation
(which also predict a one-loop loop suppression for gaugino masses), our gauge
mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos,
electroweakinos and Higgsinos can be accessible at the LHC and/or future
colliders for a wide region of the allowed parameter space.Comment: 16 pages, 1 figure. Journal version, references adde
Optical Dielectric Functions of III-V Semiconductors in Wurtzite Phase
Optical properties of semiconductors can exhibit strong polarization
dependence due to crystalline anisotropy. A number of recent experiments have
shown that the photoluminescence intensity in free standing nanowires is
polarization dependent. One contribution to this effect is the anisotropy of
the dielectric function due to the fact that most nanowires crystalize in the
wurtzite form. While little is known experimentally about the band structures
wurtzite phase III-V semiconductors, we have previously predicted the bulk band
structure of nine III-V semiconductors in wurtzite phase.Here, we predict the
frequency dependent dielectric functions for nine non-Nitride wurtzite phase
III-V semiconductors (AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs and InSb).
Their complex dielectric functions are calculated in the dipole approximation
by evaluating the momentum matrix elements on a dense grid of special k-points
using empirical pseudopotential wave functions. Corrections to the momentum
matrix elements accounting for the missing core states are made using a scaling
factor which is determined by using the optical sum rules on the calculated
dielectric functions for the zincblende polytypes. The dielectric function is
calculated for polarizations perpendicular and parallel to the c-axis of the
crystal
The Hyperbolic Higgs
We introduce the Hyperbolic Higgs, a novel solution to the little hierarchy
problem that features Standard Model neutral scalar top partners. At one-loop
order, the protection from ultraviolet sensitivity is due to an accidental
non-compact symmetry of the Higgs potential that emerges in the infrared. Once
the general features of the effective description are detailed, a completion
that relies on a five dimensional supersymmetric framework is provided. Novel
phenomenology is compared and contrasted with the Twin Higgs scenario.Comment: 25 pages, 3 figures; v2: minor changes, JHEP version; v3 minor
correctio
The time has come to make cervical cancer prevention an essential part of comprehensive sexual and reproductive health services for HIV-positive women in low-income countries.
IntroductionHIV and cervical cancer are intersecting epidemics that disproportionately affect one of the most vulnerable populations in the world: women in low- and middle-income countries (LMICs). Historically, the disparity in cervical cancer risk for women in LMICs has been due to the lack of organized screening and prevention programmes. In recent years, this risk has been augmented by the severity of the HIV epidemic in LMICs. HIV-positive women are at increased risk for developing cervical precancer and cancer, and while the introduction of antiretroviral therapy has dramatically improved life expectancies among HIV-positive women it has not been shown to improve cancer-related outcomes. Therefore, an increasing number of HIV-positive women are living in LMICs with limited or no access to cervical cancer screening programmes. In this commentary, we describe the gaps in cervical cancer prevention, the state of evidence for integrating cervical cancer prevention into HIV programmes and future directions for programme implementation and research.DiscussionDespite the biologic, behavioural and demographic overlap between HIV and cervical cancer, cervical cancer prevention has for the most part been left out of sexual and reproductive health (SRH) services for HIV-positive women. Lower cost primary and secondary prevention strategies for cervical cancer are becoming more widely available in LMICs, with increasing evidence for their efficacy and cost-effectiveness. Going forward, cervical cancer prevention must be considered a part of the essential package of SRH services for HIV-positive women. Effective cervical cancer prevention programmes will require a coordinated response from international policymakers and funders, national governments and community leaders. Leveraging the improvements in healthcare infrastructure created by the response to the global HIV epidemic through integration of services may be an effective way to make an impact to prevent cervical cancer among HIV-positive women, but more work remains to determine optimal approaches.ConclusionsCervical cancer prevention is an essential part of comprehensive HIV care. In order to ensure maximal impact and cost-effectiveness, implementation strategies for screening programmes must be adapted and rigorously evaluated through a framework that includes equal participation with policymakers, programme planners and key stakeholders in the target communities
There is no special problem about scientific representation
We propose that scientific representation is a special case of a more general notion of representation, and that the relatively well worked-out and plausible theories of the latter are directly applicable to the scientific special case. Construing scientific representation in this way makes the so-called Āæproblem of scientific representationĀæ look much less interesting than it has seemed to many, and suggests that some of the (hotly contested) debates in the literature are concerned with non-issues
There Is No Special Problem About Scientific Representation
In recent years, philosophers of science have devoted considerable attention to questions about scientific models, and particularly to the issue of how models can represent the world. We propose that scientific representation is best understood as a special case of a more general notion of representation, and that the relatively well worked-out and plausible philosophical theories of the latter are directly applicable to the scientific special case. Construing scientific representation in this way makes the so-called ``problem of scientific representation'' look much less interesting than it has seemed to many, and also suggests that some of the (hotly contested) debates in the literature are concerned with non-issues
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