High-precision Absolute Distance Measurement using Dual-Laser Frequency Scanned Interferometry Under Realistic Conditions

In this paper, we report on new high-precision absolute distance measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distances were determined by counting the interference fringes produced while scanning the frequencies of the two chopped lasers. High-finesse Fabry-Perot interferometers were used to determine frequency changes during scanning. Dual lasers with oppositely scanning directions, combined with a multi-distance-measurement technique previously reported, were used to cancel drift errors and to suppress vibration effects and interference fringe uncertainties. Under realistic conditions, a precision about 0.2 microns was achieved for a distance of 0.41 meters.Comment: 14 pages, 5 figures, submitted to Applied Optic

An efficient graph algorithm for dominance constraints

Dominance constraints are logical descriptions of trees that are widely used in computational linguistics. Their general satisfiability problem is known to be NP-complete. Here we identify normal dominance constraints and present an efficient graph algorithm for testing their satisfiablity in deterministic polynomial time. Previously, no polynomial time algorithm was known

The Evolution of Economic Governance in EMU

This paper examines the benefits of co-ordination in EMU in a stylised manner and how these benefits have shaped the co-ordination framework in EMU. It then discusses in detail the co-ordination experience in four areas that are particularly important for the functioning of EMU: (i) fiscal policy co-ordination under the Stability and Growth Pact (SGP); (ii) the co-ordination of structural policies under the Lisbon Strategy for Growth and Jobs; (iii) the representation and co-ordination of euro-area positions in international financial fora; and (iv) the co-ordination of macroeconomic statistics. The thrust of the findings is that EMU's system of economic governance has, overall, proven fit for purpose. The current policy assignment to the institutions and instruments that govern the conduct of economic policy in EMU is sound, even though further progress is necessary in several areas, particularly as regards external representation.Governance, EMU, euro area, co-ordination, van den Noord, D�hring, Langedijk, Nogueira-Martins,Pench, Temprano-Arroyo, Thiel

Regional Cerebral Perfusion and Cerebrovascular Reactivity in Elderly Controls With Subtle Cognitive Deficits

Background: Recent studies suggested that arterial spin labeling (ASL)-based measures of cerebral blood flow (CBF) as well as cerebral vasoreactivity to CO2 (CVR CO2) show significant alterations mainly in posterior neocortical areas both in mild cognitive impairment (MCI) and Alzheimer disease. It remains, however, unknown whether similar changes occur in at risk healthy elders without clinically overt symptoms. This longitudinal study investigated patterns of ASL perfusion and CVR CO2 as a function of the cognitive trajectories in asymptomatic elderly individuals.Methods: Seventy-nine community-dwelling subjects (mean age: 78.7 years, 34 male) underwent three neuropsychological assessments during a subsequent 3-year period. Individuals were classified as stable-stable (SS), variable (V), or progressive-progressive (PP). Between-group comparisons were conducted for ASL CBF and transit-time delay maps and β-maps of CO2 response. Spearman’s rho maps assessed the correlation between ASL (respectively, CVR CO2 measures) and Shapes test for working memory, as well as Verbal fluency test for executive functions. Three group-with-continuous-covariate-interaction designs were implemented to investigate group-based differences on the association between neuropsychological scores and ASL or CO2 measures.Results: Comparison of CBF maps demonstrates significantly lower perfusion in the V-group as to PP-cases predominantly in parietal regions, including the precuneus and, to a lesser degree, in temporal and frontal cortex. A stronger CVR CO2 response was found in the PP-group in left parietal areas compared to the V-group. V-cases showed a stronger ASL-Shape value relationship than V-group in right temporoparietal junction and superior parietal lobule. CO2-Shape value correlation was significantly higher in both SS and PP-groups compared to the V-group in right insular and superior perisylvian regions.Conclusion: Our data indicate the presence of decreased ASL and CVR CO2 values mainly in parietal and fronto-temporal areas in cases with the first signs of cognitive instability (V-group). Importantly, the PP-group, at high risk for MCI transition, displays an increase of both parameters in the same areas. Clinicoradiologic correlations also indicate a clear distinction between the V-group and both PP and SS-cases. These data imply the presence of an inverted U-shape pattern of regional blood flow and CVR in old age that might predict subsequent cognitive fate

The perception of touch and the ventral somatosensory pathway

Preusser et al. use MRI-based lesion-symptom mapping to confirm the causal role of a ventral pathway in the perception of touch. This pathway originates downstream of the postcentral gyrus in the parietal operculum, passes the insula and the putamen, before terminating in white matter projections extending to inferior lateral prefrontal corte

Compete or rest? Willingness to compete hurt among adolescent elite athletes

Objective Training and competing despite underlying health problems is a common social practice in sport. Adolescent elite athletes are particularly vulnerable to possible health consequences of this risky behavior due to their very sensitive developmental stage. Conceptualizing this phenomenon of playing hurt as sickness presenteeism, and taking the concept of absence/presence legitimacy into account, this paper analyzes the propensity of adolescent elite athletes to compete in the face of health problems. The central aim is to empirically identify characteristics of elite sport subcultures which affect athletes’ willingness to compete hurt (WCH). Materials & methods Based on a comprehensive sample of 1138 German elite adolescent athletes from all Olympic sports (14–18 years), the paper applies classification tree analysis to analyze the social and individual determinants of the WCH. Results Determinants on three hierarchical levels were identified, including type of sport, perceptions of social pressure, coach's leadership style and athletes' age. The group with the highest WCH were athletes from technical sports who have a coach with an autocratic leadership style. Second was athletes from ball games, and those in aesthetic and weight-dependent sports, aged between 17 and 18 years old. The lowest mean WCH-score, by some distance, occurred amongst the group of endurance and power sports athletes who experienced no direct social pressure to play hurt. Conclusions The findings enhance our understanding of absence/presence legitimacy in highly competitive social contexts and contribute to the development of more effective target-group-specific health prevention programs for young athletes

Research data management with BEXIS 2 – An overview and introduction to the special session

In this talk, we will introduce the data management platform BEXIS 2 and provide an overview of its features and capabilities. We will demonstrate how BEXIS 2 can support researchers in managing their data throughout the different aspects of the data life-cycle. Since BEXIS 2 has been designed for large collaborative projects with a central data management, we will also address features relevant to decision makers and system administrators

Fabrication of low-loss III-V Bragg-reflection waveguides for parametric down-conversion

Entangled photon pairs are an important resource for quantum cryptography schemes that go beyond point-to-point communication. Semiconductor Bragg-reflection waveguides are a promising photon-pair source due to mature fabrication, integrability, large transparency window in the telecom wavelength range, integration capabilities for electro-optical devices as well as a high second-order nonlinear coefficient. To increase performance we improved the fabrication of Bragg-reflection waveguides by employing fixed-beam-moving-stage optical lithography, low pressure and low chlorine concentration etching, and resist reflow. The reduction in sidewall roughness yields a low optical loss coefficient for telecom wavelength light of alpha_reflow = 0.08(6)mm^(-1). Owing to the decreased losses, we achieved a photon pair production rate of 8800(300)(mW*s*mm)^(-1) which is 15-fold higher than in previous samples

Time-bin entanglement at telecom wavelengths from a hybrid photonic integrated circuit

Mass-deployable implementations for quantum communication require compact, reliable, and low-cost hardware solutions for photon generation, control and analysis. We present a fiber-pigtailed hybrid photonic circuit comprising nonlinear waveguides for photon-pair generation and a polymer interposer reaching 68dB of pump suppression and photon separation with >25dB polarization extinction ratio. The optical stability of the hybrid assembly enhances the quality of the entanglement, and the efficient background suppression and photon routing further reduce accidental coincidences. We thus achieve a 96(-8,+3)% concurrence and a 96(-5,+2)% fidelity to a Bell state. The generated telecom-wavelength, time-bin entangled photon pairs are ideally suited for distributing Bell pairs over fiber networks with low dispersion

Arterial oxygenation and acid-base status before and during oxygen supplementation in captive European bison (Bison bonasus) immobilized with etorphine-acepromazine-xylazine

Chemical immobilization of captive European bison (Bison bonasus) is often required for veterinary care, transportation, or husbandry practices playing an important role in conservation breeding and reintroduction of the species. We evaluated the efficiency and physiological effects of an etorphine-acepromazine-xylazine combination with supplemental oxygen in 39 captive European bison. Animals were darted with a combination of 1.4 mg of etorphine, 4.5 mg of acepromazine, and 20 mg of xylazine per 100 kg based on estimated body mass. Arterial blood was sampled on average 20 min after recumbency and again 19 min later and analyzed immediately with a portable i-STAT analyzer. Simultaneously, heart rate, respiratory rate, and rectal temperature were recorded. Intranasal oxygen was started after the first sampling at a flow rate of 10 mL.kg(-1).min(-1) of estimated body mass until the end of the procedure. The initial mean partial pressure of oxygen (PaO2) was 49.7 mmHg with 32 out of 35 sampled bison presenting with hypoxemia. We observed decreased respiratory rates and pH and mild hypercapnia consistent with a mild respiratory acidosis. After oxygen supplementation hypoxemia was resolved in 21 out of 32 bison, but respiratory acidosis was accentuated. Bison immobilized with a lower initial drug dose required supplementary injections during the procedure. We observed that lower mean rectal temperatures during the immobilization event were significantly associated with longer recovery times. For three bison, minor regurgitation was documented. No mortality or morbidity related to the immobilizations were reported for at least 2 months following the procedure. Based on our findings, we recommend a dose of 0.015 mg.kg(-1) etorphine, 0.049 mg.kg(-1) acepromazine, and 0.22 mg.kg(-1) xylazine. This dose reduced the need for supplemental injections to obtain a sufficient level of immobilization for routine management and husbandry procedures in captive European bison. Nevertheless, this drug combination is associated with development of marked hypoxemia, mild respiratory acidosis, and a small risk of regurgitation. Oxygen supplementation is strongly recommended when using this protocol