111 research outputs found
The Crystallography of Color Superconductivity
We develop the Ginzburg-Landau approach to comparing different possible
crystal structures for the crystalline color superconducting phase of QCD, the
QCD incarnation of the Larkin-Ovchinnikov-Fulde-Ferrell phase. In this phase,
quarks of different flavor with differing Fermi momenta form Cooper pairs with
nonzero total momentum, yielding a condensate that varies in space like a sum
of plane waves. We work at zero temperature, as is relevant for compact star
physics. The Ginzburg-Landau approach predicts a strong first-order phase
transition (as a function of the chemical potential difference between quarks)
and for this reason is not under quantitative control. Nevertheless, by
organizing the comparison between different possible arrangements of plane
waves (i.e. different crystal structures) it provides considerable qualitative
insight into what makes a crystal structure favorable. Together, the
qualitative insights and the quantitative, but not controlled, calculations
make a compelling case that the favored pairing pattern yields a condensate
which is a sum of eight plane waves forming a face-centered cubic structure.
They also predict that the phase is quite robust, with gaps comparable in
magnitude to the BCS gap that would form if the Fermi momenta were degenerate.
These predictions may be tested in ultracold gases made of fermionic atoms. In
a QCD context, our results lay the foundation for a calculation of vortex
pinning in a crystalline color superconductor, and thus for the analysis of
pulsar glitches that may originate within the core of a compact star.Comment: 41 pages, 13 figures, 1 tabl
Inhaled corticosteroids in COPD and onset of type 2 diabetes and osteoporosis: matched cohort study
Some studies suggest an association between onset and/or poor control of type 2 diabetes mellitus and inhaled corticosteroid (ICS) therapy for chronic obstructive pulmonary disease (COPD), and also between increased fracture risk and ICS therapy; however, study results are contradictory and these associations remain tentative and incompletely characterized. This matched cohort study used two large UK databases (1983â2016) to study patients (â„ 40 years old) initiating ICS or long-acting bronchodilator (LABD) for COPD from 1990â2015 in three study cohorts designed to assess the relation between ICS treatment and (1) diabetes onset (N = 17,970), (2) diabetes progression (N = 804), and (3) osteoporosis onset (N = 19,898). Patients had â„ 1-year baseline and â„ 2-year outcome data. Matching was via combined direct matching and propensity scores. Conditional proportional hazards regression, adjusting for residual confounding after matching, was used to compare ICS vs. LABD and to model ICS exposures. Median follow-up was 3.7â5.6 years/treatment group. For patients prescribed ICS, compared with LABD, the risk of diabetes onset was significantly increased (adjusted hazard ratio 1.27; 95% CI, 1.07â1.50), with overall no increase in risk of diabetes progression (adjusted hazard ratio 1.04; 0.87â1.25) or osteoporosis onset (adjusted hazard ratio 1.13; 0.93â1.39). However, the risks of diabetes onset, diabetes progression, and osteoporosis onset were all significantly increased, with evident doseâresponse relationships for all three outcomes, at mean ICS exposures of 500 ”g/day or greater (vs. < 250 ”g/day, fluticasone propionateâequivalent). Long-term ICS therapy for COPD at mean daily exposure of â„ 500 ”g is associated with an increased risk of diabetes, diabetes progression, and osteoporosis
A Theory for the High-T_c Cuprates: Anomalous Normal-State and Spectroscopic Properties, Phase Diagram, and Pairing
A theory of highly correlated layered superconducting materials isapplied for
the cuprates. Differently from an independent-electron approximation, their
low-energy excitations are approached in terms of auxiliary particles
representing combinations of atomic-like electron configurations, where the
introduction of a Lagrange Bose field enables treating them as bosons or
fermions. The energy spectrum of this field accounts for the tendency of
hole-doped cuprates to form stripe-like inhomogeneities. Consequently, it
induces a different analytical behavior for auxiliary particles corresponding
to "antinodal" and "nodal" electrons, enabling the existence of different
pairing temperatures at T^* and T_c. This theory correctly describes the
observed phase diagram of the cuprates, including the non-Fermi-liquid to FL
crossover in the normal state, the existence of Fermi arcs below T^* and of a
"marginal-FL" critical behavior above it. The qualitative anomalous behavior of
numerous physical quantities is accounted for, including kink- and
waterfall-like spectral features, the drop in the scattering rates below T^*
and more radically below T_c, and an effective increase in the density of
carriers with T and \omega, reflected in transport, optical and other
properties. Also is explained the correspondence between T_c, the
resonance-mode energy, and the "nodal gap".Comment: 28 pages, 7 figure
Towards evidence-based marketing: The case of childhood obesity
Contentious commodities such as tobacco, alcohol and fatty foods are bringing marketing under scrutiny from consumers and policymakers. Yet there is little agreement on whether marketing is harmful to society. Systematic review (SR), a methodology derived from clinical medicine, offers marketers a tool for providing resolution and allowing policymakers to proceed with greater confidence. This article describes how SR methods were applied for the first time to a marketing problem -- the effects of food promotion to children. The review withstood scrutiny and its findings were formally ratified by government bodies and policymakers, demonstrating that SR methods can transfer from clinical research to marketing
Age at first birth in women is genetically associated with increased risk of schizophrenia
Prof. Paunio on PGC:n jÀsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe
Macroinvertebrate Monitoring of Redmond and Blakely Ridge Ephemeral Streams
Since the early 1980âs biological monitoring has developed as a reliable tool for the assessment
of stream and watershed health in an ecological context broader than traditional chemical and
habitat assessment. In late May of 1991, macroinvertebrate samples were collected from 6
streams and 2 wetlands in the proposed Blakely and Redmond Ridge development projects
(UPD) as a biological component of the project monitoring plan. The 1991 collections were
intended to represent a pre-development, biological baseline upon which future monitoring
efforts could be based. In an attempt to evaluate the streams using the benthic index of biological
integrity (B-IBI), macroinvertebrates were again collected in late September 1997 from 5
streams sites and in late September 1998 from 1 stream in the development area. The researchers
found the study streams were variably ephemeral and thus not appropriate for use in a standard
Fall analysis using Puget Sound lowland B-IBI.
To address the ephemeral streams dilemma, a project was undertaken to determine a
period of time during which the UPD streams could be sampled and evaluated using
macroinvertebrates. Following the methods outlined in Karr and Chu (1999), samples were to be
taken at two week intervals beginning in late May on 7 small streams draining the development
area. Sampling would be halted when stream dewatering inhibited sampling efforts. The set of
samples taken two weeks prior to the early drying of streams would then be analyzed to represent
the macroinvertebrate fauna present during the latest appropriate time for sampling the
ephemeral streams and the response of that fauna to varying levels of human impact on the
watershed. The spring and summer 1999 macroinvertebrate assessment effort and lessons from
the study will be described in this report.Xerces Societ
A microfabricated atmospheric-pressure microplasma source operating in air
An atmospheric-pressure air microplasma is ignited and sustained in a 25ÎŒm wide discharge gap formed between two co-planar gold electrodes.
These electrodes are the two ends of a microstrip transmission line that is
microfabricated on an Al2O3 substrate in the shape of a split-ring resonator
operating with a resonant frequency of 895 MHz. At resonance, the device
creates a peak gap voltage of ~390V with an input power of 3W, which is
sufficient to initiate a plasma in atmospheric pressure air. Optical emission
from the discharge is primarily in the ultraviolet region. In spite of an
arc-like appearance, the discharge is not in thermal equilibrium as the N2
rotational temperature is 500â700 K. The intrinsic heating of the Al2O3
substrate (to 100°C) causes a downward shift in the resonant frequency of
the device due to thermal expansion. The temperature rise also results in a
slight decrease in the quality factor (142 > Q > 134) of the resonator. By
decreasing the power supply frequency or using a heat sink, the
microplasma is sustained in air. Microscopic inspection of the discharge gap
shows no plasma-induced erosion after 50 h of use
- âŠ