1,148 research outputs found
The Cosmic Microwave Background and Particle Physics
In forthcoming years, connections between cosmology and particle physics will
be made increasingly important with the advent of a new generation of cosmic
microwave background (CMB) experiments. Here, we review a number of these
links. Our primary focus is on new CMB tests of inflation. We explain how the
inflationary predictions for the geometry of the Universe and primordial
density perturbations will be tested by CMB temperature fluctuations, and how
the gravitational waves predicted by inflation can be pursued with the CMB
polarization. The CMB signatures of topological defects and primordial magnetic
fields from cosmological phase transitions are also discussed. Furthermore, we
review current and future CMB constraints on various types of dark matter (e.g.
massive neutrinos, weakly interacting massive particles, axions, vacuum
energy), decaying particles, the baryon asymmetry of the Universe,
ultra-high-energy cosmic rays, exotic cosmological topologies, and other new
physics.Comment: 43 pages. To appear in Annual Reviews of Nuclear and Particle Scienc
Female partners of patients after surgical prostate cancer treatment: interactions with physicians and support needs
<p>Abstract</p> <p>Background</p> <p>Few studies have explored the women's experiences as a result of a partners' diagnosis of prostate cancer. This study begins to explore women's interactions with physicians (primary care and urologist) and the support needs associated with the diagnosis and treatment of their partners' prostate cancer.</p> <p>Methods</p> <p>Two focus groups (n = 14) of women whose partners were diagnosed with prostate cancer (diagnoses' 1 - 18 months). A trained facilitator used open-ended questions to explore ideas. The framework approach was used to analyze the transcripts.</p> <p>Results</p> <p>Three main themes emerged: 1. <b>More support</b>. Validation and information is needed for women including emotional support and opportunities to share experiences. 2. <b>Role of the physician</b>. The transfer of care once specialized treatment is no longer needed remained poorly defined, which increased confusion and feelings of abandonment related to the role of the primary physician. 3. <b>Partners' relationship changes</b>. Men became more dependent on their partners for support and to act as the primary communicator and caregiver.</p> <p>Conclusions</p> <p>Additional research is needed in this field to confirm the importance of training primary care physicians to consider holistic treatment approaches that recognize the partner and family needs as important in the complete physical and emotional healing of their patients.</p
Aidnogenesis via Leptogenesis and Dark Sphalerons
We discuss aidnogenesis, the generation of a dark matter asymmetry via new
sphaleron processes associated to an extra non-abelian gauge symmetry common to
both the visible and the dark sectors. Such a theory can naturally produce an
abundance of asymmetric dark matter which is of the same size as the lepton and
baryon asymmetries, as suggested by the similar sizes of the observed baryonic
and dark matter energy content, and provide a definite prediction for the mass
of the dark matter particle. We discuss in detail a minimal realization in
which the Standard Model is only extended by dark matter fermions which form
"dark baryons" through an SU(3) interaction, and a (broken) horizontal symmetry
that induces the new sphalerons. The dark matter mass is predicted to be
approximately 6 GeV, close to the region favored by DAMA and CoGeNT.
Furthermore, a remnant of the horizontal symmetry should be broken at a lower
scale and can also explain the Tevatron dimuon anomaly.Comment: Minor changes, discussion of present constraints expanded. 16 pages,
2 eps figures, REVTeX
The Cosmology of Composite Inelastic Dark Matter
Composite dark matter is a natural setting for implementing inelastic dark
matter - the O(100 keV) mass splitting arises from spin-spin interactions of
constituent fermions. In models where the constituents are charged under an
axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark
matter scatters inelastically off Standard Model nuclei and can explain the
DAMA/LIBRA annual modulation signal. This article describes the early Universe
cosmology of a minimal implementation of a composite inelastic dark matter
model where the dark matter is a meson composed of a light and a heavy quark.
The synthesis of the constituent quarks into dark mesons and baryons results in
several qualitatively different configurations of the resulting dark matter
hadrons depending on the relative mass scales in the system.Comment: 31 pages, 4 figures; references added, typos correcte
Electroweak Baryogenesis and Dark Matter with an approximate R-symmetry
It is well known that R-symmetric models dramatically alleviate the SUSY
flavor and CP problems. We study particular modifications of existing
R-symmetric models which share the solution to the above problems, and have
interesting consequences for electroweak baryogenesis and the Dark Matter (DM)
content of the universe. In particular, we find that it is naturally possible
to have a strongly first-order electroweak phase transition while
simultaneously relaxing the tension with EDM experiments. The R-symmetry (and
its small breaking) implies that the gauginos (and the neutralino LSP) are
pseudo-Dirac fermions, which is relevant for both baryogenesis and DM. The
singlet superpartner of the U(1)_Y pseudo-Dirac gaugino plays a prominent role
in making the electroweak phase transition strongly first-order. The
pseudo-Dirac nature of the LSP allows it to behave similarly to a Dirac
particle during freeze-out, but like a Majorana particle for annihilation today
and in scattering against nuclei, thus being consistent with current
constraints. Assuming a standard cosmology, it is possible to simultaneously
have a strongly first-order phase transition conducive to baryogenesis and have
the LSP provide the full DM relic abundance, in part of the allowed parameter
space. However, other possibilities for DM also exist, which are discussed. It
is expected that upcoming direct DM searches as well as neutrino signals from
DM annihilation in the Sun will be sensitive to this class of models.
Interesting collider and Gravity-wave signals are also briefly discussed.Comment: 50 pages, 10 figure
Stochastic Gravity: Theory and Applications
Whereas semiclassical gravity is based on the semiclassical Einstein equation
with sources given by the expectation value of the stress-energy tensor of
quantum fields, stochastic semiclassical gravity is based on the
Einstein-Langevin equation, which has in addition sources due to the noise
kernel.In the first part, we describe the fundamentals of this new theory via
two approaches: the axiomatic and the functional. In the second part, we
describe three applications of stochastic gravity theory. First, we consider
metric perturbations in a Minkowski spacetime: we compute the two-point
correlation functions for the linearized Einstein tensor and for the metric
perturbations. Second, we discuss structure formation from the stochastic
gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in
the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit
Stochastic Gravity: Theory and Applications
Whereas semiclassical gravity is based on the semiclassical Einstein equation
with sources given by the expectation value of the stress-energy tensor of
quantum fields, stochastic semiclassical gravity is based on the
Einstein-Langevin equation, which has in addition sources due to the noise
kernel. In the first part, we describe the fundamentals of this new theory via
two approaches: the axiomatic and the functional. In the second part, we
describe three applications of stochastic gravity theory. First, we consider
metric perturbations in a Minkowski spacetime, compute the two-point
correlation functions of these perturbations and prove that Minkowski spacetime
is a stable solution of semiclassical gravity. Second, we discuss structure
formation from the stochastic gravity viewpoint. Third, we discuss the
backreaction of Hawking radiation in the gravitational background of a black
hole and describe the metric fluctuations near the event horizon of an
evaporating black holeComment: 100 pages, no figures; an update of the 2003 review in Living Reviews
in Relativity gr-qc/0307032 ; it includes new sections on the Validity of
Semiclassical Gravity, the Stability of Minkowski Spacetime, and the Metric
Fluctuations of an Evaporating Black Hol
The Cosmological Constant
This is a review of the physics and cosmology of the cosmological constant.
Focusing on recent developments, I present a pedagogical overview of cosmology
in the presence of a cosmological constant, observational constraints on its
magnitude, and the physics of a small (and potentially nonzero) vacuum energy.Comment: 50 pages. Submitted to Living Reviews in Relativity
(http://www.livingreviews.org/), December 199
Pharmacological inhibition of leukotrienes in an animal model of bleomycin-induced acute lung injury
Leukotrienes are increased locally in idiopathic pulmonary fibrosis. Furthermore, a role for these arachidonic acid metabolites has been thoroughly characterized in the animal bleomycin model of lung fibrosis by using different gene knock-out settings. We investigated the efficacy of pharmacological inhibition of leukotrienes activity in the development of bleomycin-induced lung injury by comparing the responses in wild-type mice with mice treated with zileuton, a 5-lipoxygenase inhibitor and MK-571, a cys-leukotrienes receptor antagonist. Mice were subjected to intra-tracheal administration of bleomycin or saline and were assigned to receive either MK-571 at 1 mg/Kg or zileuton at 50 mg/Kg daily. One week after bleomycin administration, BAL cell counts, lung histology with van Gieson for collagen staining and immunohistochemical analysis for myeloperoxidase, IL-1 and TNF-α were performed. Following bleomycin administration both MK-571 and zileuton treated mice exhibited a reduced degree of lung damage and inflammation when compared to WT mice as shown by the reduction of:(i) loss of body weight, (ii) mortality rate, (iii) lung infiltration by neutrophils (myeloperoxidase activity, BAL total and differential cell counts), (iv) lung edema, (v) histological evidence of lung injury and collagen deposition, (vi) lung myeloperoxidase, IL-1 and TNF-α staining. This is the first study showing that the pharmacological inhibition of leukotrienes activity attenuates bleomycin-induced lung injury in mice. Given our results as well as those coming from genetic studies, it might be considered meaningful to trial this drug class in the treatment of pulmonary fibrosis, a disease that still represents a major challenge to medical treatment
Military veteran mortality following a survived suicide attempt
<p>Abstract</p> <p>Background</p> <p>Suicide is a global public health problem. Recently in the U.S., much attention has been given to preventing suicide and other premature mortality in veterans returning from Iraq and Afghanistan. A strong predictor of suicide is a past suicide attempt, and suicide attempters have multiple physical and mental comorbidities that put them at risk for additional causes of death. We examined mortality among U.S. military veterans after hospitalization for attempted suicide.</p> <p>Methods</p> <p>A retrospective cohort study was conducted with all military veterans receiving inpatient treatment during 1993-1998 at United States Veterans Affairs (VA) medical facilities following a suicide attempt. Deaths occurring during 1993-2002, the most recent available year at the time, were identified through VA Beneficiary and Records Locator System data and National Death Index data. Mortality data for the general U.S. adult population were also obtained from the National Center for Health Statistics. Comparisons within the veteran cohort, between genders, and against the U.S. population were conducted with descriptive statistics and standardized mortality ratios. The actuarial method was used estimate the proportion of veterans in the cohort we expect would have survived through 2002 had they experienced the same rate of death that occurred over the study period in the U.S. population having the age and sex characteristics.</p> <p>Results</p> <p>During 1993-1998, 10,163 veterans were treated and discharged at a VA medical center after a suicide attempt (mean age = 44 years; 91% male). There was a high prevalence of diagnosed alcohol disorder or abuse (31.8%), drug dependence or abuse (21.8%), psychoses (21.2%), depression (18.5%), and hypertension (14.2%). A total of 1,836 (18.1%) veterans died during follow up (2,941.4/100,000 person years). The cumulative survival probability after 10 years was 78.0% (95% CI = 72.9, 83.1). Hence the 10-year cumulative mortality risk was 22.0%, which was 3.0 times greater than expected. The leading causes overall were heart disease (20.2%), suicide (13.1%), and unintentional injury (12.7%). Whereas suicide was the ninth leading cause of death in the U.S. population overall (1.8%) during the study period, suicide was the leading and second leading cause among women (25.0%) and men (12.7%) in the cohort, respectively.</p> <p>Conclusions</p> <p>Veterans who have attempted suicide face elevated risks of all-cause mortality with suicide being prominent. This represents an important population for prevention activities.</p
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