2,132 research outputs found
Abelian arithmetic Chern-Simons theory and arithmetic linking numbers
Following the method of Seifert surfaces in knot theory, we define arithmetic
linking numbers and height pairings of ideals using arithmetic duality
theorems, and compute them in terms of n-th power residue symbols. This
formalism leads to a precise arithmetic analogue of a 'path-integral formula'
for linking numbers
Macroeconomic impacts of demographic change in Scotland : a computable general equilibrium analysis
This paper combines a multi-period economic Computable General Equilibrium (CGE) modelling framework with a demographic model to analyse the macroeconomic impact of the projected demographic trends in Scotland. Demographic trends are defined by the existing fertility-mortality rates and the level of annual net-migration. We employ a combination of a demographic and a CGE simulation to track the impact of changes in demographic structure upon macroeconomic variables under different scenarios for annual migration. We find that positive net migration can cancel the expected negative impact upon the labour market of other demographic changes. (Pressure on wages, falling employment). However, the required size of the annual net-migration is far higher than the current trends. The policy implication suggested by the results is that active policies are needed to attract migrants. We nevertheless report results when varying fertility and mortality assumptions. The impact of varying those assumptions is rather small
Macroeconomic Impact of Ageing Population in Scotland. A Computable General Equilibrium Analysis.
This paper combines a multi-period economic Computable General Equilibrium (CGE) modelling framework with a demographic model to analyse the macroeconomic impact of the projected demographic trends in Scotland. Demographic trends are defined by the existing fertility-mortality rates and the level of annual net-migration. We employ a combination of a demographic and a CGE simulation to track the impact of changes in demographic structure upon macroeconomic variables under different scenarios for annual migration. We find that positive net migration can cancel the expected negative impact upon the labour market of other demographic changes. (Pressure on wages, falling employment). However, the required size of the annual net-migration is far higher than the current trends. The policy implication suggested by the results is that active policies are needed to attract migrants. We nevertheless report results when varying fertility and mortality assumptions. The impact of varying those assumptions is rather small.
Electric-field noise from carbon-adatom diffusion on a Au(110) surface: first-principles calculations and experiments
The decoherence of trapped-ion quantum gates due to heating of their motional
modes is a fundamental science and engineering problem. This heating is
attributed to electric-field noise arising from the trap-electrode surfaces. In
this work, we investigate the source of this noise by focusing on the diffusion
of carbon-containing adsorbates on the surface of Au(110). We show by density
functional theory, based on detailed scanning probe microscopy, how the carbon
adatom diffusion on the gold surface changes the energy landscape, and how the
adatom dipole moment varies with the diffusive motion. A simple model for the
diffusion noise, which varies quadratically with the variation of the dipole
moment, qualitatively reproduces the measured noise spectrum, and the estimate
of the noise spectral density is in accord with measured values.Comment: 8 pages, 6 figure
Consumers' Shopping Patterns and Expenditures on Ethnic Produce: A Case Study from the Eastern Coastal U.S.A.
This study was undertaken to examine the possible niche markets which East Coast farmers might be able to use to regain their advantage. Their future economic success could hinge on shifting the focus from traditional fruits and vegetables to high-value specialty ethnic produce for which there might be a growing demand. The study results indicate that there is a strong market demand and interest for ethnic produce in the East Coast. Local producers can benefit by concentrating their efforts in producing ethnic vegetables and fresh produce and making these newer products available in the local and regional markets.Food Consumption/Nutrition/Food Safety,
Single Cell Manipulation using Ferromagnetic Composite Microtransporters
For biomedical applications, such as single cell manipulation, it is important to fabricate microstructures that can be powered and controlled wirelessly in fluidic environments. In this letter, we describe the construction and operation of truly micron-sized, biocompatible ferromagnetic microtransporters driven by external magnetic fields. Microtransporters were fabricated using a simple, single step fabrication method and can be produced in large numbers. We demonstrate that they can be navigated to manipulate single cells with micron-size precision without disturbing the local environment
Modulating calcium phosphate formation using CO2 laser engineering of a polymeric material
The use of simulated body fluid (SBF) is widely used as a screening technique to assess the ability of materials to promote calcium phosphate formation. This paper details the use of CO2 laser surface treatment of nylon® 6,6 to modulate calcium phosphate formation following immersion in SBF for 14 days. Through white light interferometry (WLI) it was determined that the laser surface processing gave rise to maximum Ra and Sa parameters of 1.3 and 4.4 µm, respectively. The use of X-ray photoelectron spectroscopy (XPS) enabled a maximum increase in surface oxygen content of 5.6 %at. to be identified. The laser-induced surface modifications gave rise to a modulation in the wettability characteristics such that the contact angle, θ, decreased for the whole area processed samples, as expected, and increased for the patterned samples. The increase in θ can be attributed to a transition in wetting nature to a mixed-state wetting regime. It was seen for all samples that calcium phosphate formed on each surface following 14 days. The largest increase in mass, Δg, owed to calcium phosphate formation, was brought about by the whole area processed sample irradiated with a fluence of 51 Jcm-2. No correlation between the calcium phosphate formation and the laser patterned surface properties was determined due to the likely affect of the mixed-state wetting regime. Strong correlations between θ, the surface energy parameters and the calcium phosphate formation for the whole area processed samples allow one to realize the potential for this surface treatment technique in predicting the bone forming ability of laser processed materials
The impact of United States Medical Licensing Exam (USMLE) step 1 cutoff scores on recruitment of underrepresented minorities in medicine: A retrospective cross-sectional study.
Background and Aims:United States Medical Licensing Exam (USMLE) scores are the single, most objective criteria for admission into residency programs in the country. Underrepresented minorities in medicine (URiM) are found to have lower USMLE scores compared to their White counterparts. The objective of this study is to examine how USMLE step 1 cutoff scores may exclude self-reported URiM from the residency interview process across various specialties. Methods:This was a retrospective cross-sectional study of 10 541 applicants to different residency programs at Zucker School of Medicine at Hofstra/Northwell Health between May 2014 and May 2015. We identified Blacks and Hispanics as URiM. The primary outcome is the percentage of applicants with USMLE step 1 score above different ranges of cutoff score, from 205 to 235 in five-point increments, by race/ethnicity and by URiM status. Secondary outcome is percentages of URiM vs non-URiM above and below mean USMLE step 1 scores by different specialties (internal medicine, obstetrics/gynecology, pediatrics, and psychiatry). Results:The study sample included 2707 White, 722 Black, 805 Hispanic, 5006 Asian, and 562 Other Race/Ethnicity applicants. Overall, 50.2% were male, 21.3% URiM, 7.4% had limited English proficiency, 67.6% attended international medical schools, and 2.4% are Alpha Omega Alpha Honor Medical Society (AOA) members. The mean (±SD) USMLE step 1 score was significantly greater among non-URiM applicants as compared to URiM applicants (223.7 ± 19.4 vs 216.1 ± 18.4, P \u3c .01, two-sample t-test). Non-URiM applicants were younger, and the percentage of male and AOA applicants was greater among non-URiM applicants as compared to URiM applicants (50.5% vs 47.7%, P = .02, Chi-Square test; 2.9% vs 1.2%, P \u3c .01, Chi-Square test, respectively). Conclusion:Using a USMLE step 1 cutoff score as an initial filter for applicant recruitment and selection could jeopardize the benefits of a diverse residency program. Practical implications are discussed
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