2,804 research outputs found
Spin-orbit splitting of image states
We quantify the effect of the spin-orbit interaction on the Rydberg-like
series of image state electrons at the (111) and (001) surface of Ir, Pt and
Au. Using relativistic multiple-scattering methods we find Rashba-like
dispersions with Delta E(K)=gamma K with values of gamma for n=1 states in the
range 38-88 meV Angstrom. Extending the phase-accumulation model to include
spin-orbit scattering we find that the splittings vary like 1/(n+a)^3 where a
is the quantum defect and that they are related to the probability of spin-flip
scattering at the surface. The splittings should be observable experimentally
being larger in magnitude than some exchange-splittings that have been resolved
by inverse photoemission, and are comparable to linewidths from inelastic
lifetimes.Comment: 10 pages, 4 figure
Mucus entrapment of particles by a suspension-feeding tilapia (Pisces: Cichlidae)
A miniature fiberoptic endoscope was used to observe the processes of particle encounter and retention inside the buccopharyngeal cavity of suspension-feeding tilapia. Small particles (38 µm to 1.0 mm in diameter) were trapped in strands and aggregates of mucus, which usually slid posteriorly on the ceratobranchials of arches IIV towards the esophagus while the fish pumped water through the buccopharyngeal cavity. During stage 1 of periodic reversals of water flow inside the buccopharynx, mucus-bound particles usually lifted off the arch surfaces and travelled a short distance in an anterior or anterodorsal direction. During stage 2 of a reversal, the mucus usually resumed travel in a posterior or posteroventral direction and exited the field of view. Mucus was present less often during feeding on large particles (310 mm in diameter) than on small particles, and large particles were rarely observed to be attached to mucus. We discuss the advantages to suspension-feeding fishes of using aerosol filtration by mucus entrapment rather than sieving, and predict that many cichlid and cyprinid suspension feeders that consume bacteria and phytoplankton use mucus for aerosol filtration
Why Pad\'e Approximants reduce the Renormalization-Scale dependence in QFT?
We prove that in the limit where the beta function is dominated by the 1-loop
contribution (``large beta_0 limit'') diagonal Pad\'e Approximants (PA's) of
perturbative series become exactly renormalization scale (RS) independent. This
symmetry suggest that diagonal PA's are resumming correctly contributions from
higher order diagrams that are responsible for the renormalization of the
coupling-constant. Non-diagonal PA's are not exactly invariant, but generally
reduce the RS dependence as compared to partial-sums. In physical cases,
higher-order corrections in the beta function break the symmetry softly,
introducing a small scale and scheme dependence. We also compare the Pad\'e
resummation with the BLM method. We find that in the large-N_f limit using the
BLM scale is identical to resumming the series by a non-diagonal PA.Comment: 25 pages, LateX. Replaced so that the figures would fit into the page
siz
A system�based intervention to reduce Black�White disparities in the treatment of early stage lung cancer: A pragmatic trial at five cancer centers
Background: Advances in early diagnosis and curative treatment have reduced high
mortality rates associated with non�small cell lung cancer. However, racial disparity
in survival persists partly because Black patients receive less curative treatment than
White patients.
Methods: We performed a 5�year pragmatic, trial at five cancer centers using a system�based intervention. Patients diagnosed with early stage lung cancer, aged 18�85
were eligible. Intervention components included: (1) a real�time warning system derived from electronic health records, (2) race�specific feedback to clinical teams on
treatment completion rates, and (3) a nurse navigator. Consented patients were compared to retrospective and concurrent controls. The primary outcome was receipt of
curative treatment.
Results: There were 2841 early stage lung cancer patients (16% Black) in the retrospective group and 360 (32% Black) in the intervention group. For the retrospective
baseline, crude treatment rates were 78% for White patients vs 69% for Black patients (P < 0.001); difference by race was confirmed by a model adjusted for age,
treatment site, cancer stage, gender, comorbid illness, and income�odds ratio (OR)
0.66 for Black patients (95% CI 0.51�0.85, P = 0.001). Within the intervention cohort, the crude rate was 96.5% for Black vs 95% for White patients (P = 0.56). Odds
ratio for the adjusted analysis was 2.1 (95% CI 0.41�10.4, P = 0.39) for Black vs
White patients. Between group analyses confirmed treatment parity for the
intervention.
Conclusion: A system�based intervention tested in five cancer centers reduced racial
gaps and improved care for all
The Pine Needle, May 1947
Libraries and archives collect materials from different cultures and time periods to preserve and make available the historical record. As a result, materials such as those presented here may reflect sexist, misogynistic, abusive, racist, or discriminatory attitudes or actions that some may find disturbing, harmful, or difficult to view.
Both a humor and literary magazine, The Pine Needle was a University of Maine student-produced periodical that began publication in the fall of 1946, the first post-World War II semester that saw GIs returning to campus.
The Needle reflected an edginess and rebellion not found in previous student publications. While past student publications relied on euphemisms for alcohol and dating on campus, The Needle openly promoted the sexualization of co-eds and the use of drugs, tobacco, and alcohol by students who experienced war.
In response to Alumni complaints that The Needle was ...filled with sex and drinking, the University Publications Committee instituted stricter controls. In this issue, the editorial staff announce that starting in Fall 1947, the publication would publish only four issues of the magazine each year—Fall, Christmas, Spring, and Graduation among other changes.
Cover art for this issue is an unsigned ink illustration of chatting university students lined up outside a shop bearing a sign that reads Jifty Cleaners-Dyers. Signs in the shop window reads We Specialize in Grass Stains. 24 Hour Service
Applying a genetic risk score for prostate cancer to men with lower urinary tract symptoms in primary care to predict prostate cancer diagnosis : a cohort study in the UK Biobank
Background Prostate cancer is highly heritable, with >250 common variants associated in genome-wide association studies. It commonly presents with non-specific lower urinary tract symptoms that are frequently associated with benign conditions. Methods Cohort study using UK Biobank data linked to primary care records. Participants were men with a record showing a general practice consultation for a lower urinary tract symptom. The outcome measure was prostate cancer diagnosis within 2 years of consultation. The predictor was a genetic risk score of 269 genetic variants for prostate cancer. Results A genetic risk score (GRS) is associated with prostate cancer in symptomatic men (OR per SD increase = 2.12 [1.86-2.41] P = 3.5e-30). An integrated risk model including age and GRS applied to symptomatic men predicted prostate cancer (AUC 0.768 [0.739-0.796]). Prostate cancer incidence was 8.1% (6.7-9.7) in the highest risk quintile. In the lowest quintile, prostate cancer incidence was Conclusions This study is the first to apply GRS in primary care to improve the triage of symptomatic patients. Men with the lowest genetic risk of developing prostate cancer could safely avoid invasive investigation, whilst those identified with the greatest risk could be fast-tracked for further investigation. These results show that a GRS has potential application to improve the diagnostic pathway of symptomatic patients in primary care.Peer reviewe
Natural selection towards wild-type in composite cross populations of winter wheat
Most of our crops are grown in monoculture with single genotypes grown over wide acreage. An alternative approach, where segregating populations are used as crops, is an exciting possibility, but outcomes of natural selection upon this type of crop are not well understood. We tracked allelic frequency changes in evolving composite cross populations of wheat grown over ten generations under organic and conventional farming. At three generations, each population was genotyped with 19 SSR and 8 SNP markers. The latter were diagnostic for major functional genes. Gene diversity was constant at SSR markers but decreased over time for SNP markers. Population differentiation between the four locations could not be detected, suggesting that organic vs. non-organic crop management did not drive allele frequency changes. However, we did see changes for genes controlling plant height and phenology in all populations independently and consistently. We interpret these changes as the result of a consistent natural selection towards wild-type. Independent selection for alleles that are associated with plant height suggests that competition for light was central, resulting in the predominance of stronger intraspecific competitors, and highlighting a potential trade-off between individual and population performanc
Bargmann invariants and off-diagonal geometric phases for multi-level quantum systems -- a unitary group approach
We investigate the geometric phases and the Bargmann invariants associated
with a multi-level quantum systems. In particular, we show that a full set of
`gauge-invariant' objects for an -level system consists of geometric
phases and algebraically independent 4-vertex Bargmann
invariants. In the process of establishing this result we develop a canonical
form for U(n) matrices which is useful in its own right. We show that the
recently discovered `off-diagonal' geometric phases [N. Manini and F.
Pistolesi, Phys. Rev. Lett. 8, 3067 (2000)] can be completely analysed in terms
of the basic building blocks developed in this work. This result liberates the
off-diagonal phases from the assumption of adiabaticity used in arriving at
them.Comment: 13 pages, latex, no figure
Geometric Phase: a Diagnostic Tool for Entanglement
Using a kinematic approach we show that the non-adiabatic, non-cyclic,
geometric phase corresponding to the radiation emitted by a three level cascade
system provides a sensitive diagnostic tool for determining the entanglement
properties of the two modes of radiation. The nonunitary, noncyclic path in the
state space may be realized through the same control parameters which control
the purity/mixedness and entanglement. We show analytically that the geometric
phase is related to concurrence in certain region of the parameter space. We
further show that the rate of change of the geometric phase reveals its
resilience to fluctuations only for pure Bell type states. Lastly, the
derivative of the geometric phase carries information on both purity/mixedness
and entanglement/separability.Comment: 13 pages 6 figure
Generalization of geometric phase to completely positive maps
We generalize the notion of relative phase to completely positive maps with
known unitary representation, based on interferometry. Parallel transport
conditions that define the geometric phase for such maps are introduced. The
interference effect is embodied in a set of interference patterns defined by
flipping the environment state in one of the two paths. We show for the qubit
that this structure gives rise to interesting additional information about the
geometry of the evolution defined by the CP map.Comment: Minor revision. 2 authors added. 4 pages, 2 figures, RevTex
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