723 research outputs found
Formation of a molecular Bose-Einstein condensate and an entangled atomic gas by Feshbach resonance
Processes of association in an atomic Bose-Einstein condensate, and
dissociation of the resulting molecular condensate, due to Feshbach resonance
in a time-dependent magnetic field, are analyzed incorporating non-mean-field
quantum corrections and inelastic collisions. Calculations for the Na atomic
condensate demonstrate that there exist optimal conditions under which about
80% of the atomic population can be converted to a relatively long-lived
molecular condensate (with lifetimes of 10 ms and more). Entangled atoms in
two-mode squeezed states (with noise reduction of about 30 dB) may also be
formed by molecular dissociation. A gas of atoms in squeezed or entangled
states can have applications in quantum computing, communications, and
measurements.Comment: LaTeX, 5 pages with 4 figures, uses REVTeX
Paleoseismological evidence of holocene activity of the Los Tollos fault (Murcia, se Spain): a lately formed quaternary tectonic feature of the eastern betic shear zone
The Los Tollos Fault is a recent and important feature of the Eastern Betic Shear Zone, one of the major tectonic structures in South Iberia accommodating the convergence between Nubian and Eurasian plates in the western Mediterranean. The Los Tollos Fault became active by the end of Middle Pleistocene introducing some paleogeographical modifications. Previously mapped as a secondary normal fault related to the Carrascoy Fault, recent research evidences that the Los Tollos Fault is an independent Holocene active left-lateral reverse fault extending for at least 15 km. Data analysis from 4 trenches dug across the fault has revealed the occurrence of at least two paleo-earthquake events during the Holocene. The most recent event is dated between 2,740 and 2,140 yr BP (8th to 2nd centuries BC). The size of the paleoevents is calculated to be Mw 6.3 – 6.6 following empirical regressions on surface rupture length. The recurrence interval is estimated to be between 2,200-6,860 years, fitting a slip rate for the fault between 0.12 and 0.17 mm/yr. Such parameters highlight the Los Tollos Fault as a tectonic structure with a considerable activity located relatively close to densely populated areas. These seismogenic parameters should be considered in future reassessments of the seismic hazard of the regionThis work forms part of the research activities carried out in the FASEGEO Project (CGL2009-09726) funded by the Spanish Ministry of Science and Innovatio
Statistical disclosure control in tabular data
Data disseminated by National Statistical Agencies (NSAs) can be classified
as either microdata or tabular data. Tabular data is obtained from microdata by
crossing one or more categorical variables. Although cell tables provide aggregated
information, they also need to be protected. This chapter is a short introduction to
tabular data protection. It contains three main sections. The first one shows the different
types of tables that can be obtained, and how they are modeled. The second
describes the practical rules for detection of sensitive cells that are used by NSAs.
Finally, an overview of protection methods is provided, with a particular focus on
two of them: “cell suppression problem” and “controlled tabular adjustment”.Postprint (published version
Myosin Light Chain Kinase (MLCK) Gene Influences Exercise Induced Muscle Damage during a Competitive Marathon
Myosin light chain kinase (MLCK) phosphorylates the regulatory light chain (RLC) of myosin producing increases in force development during skeletal muscle contraction. It has been suggested that MLCK gene polymorphisms might alter RLC phosphorylation thereby decreasing the ability to produce force and to resist strain during voluntary muscle contractions. Thus, the genetic variations in the MLCK gene might predispose some individuals to higher values of muscle damage during exercise, especially during endurance competitions. The aim of this investigation was to determine the influence of MLCK genetic variants on exercise-induced muscle damage produced during a marathon. Sixty-seven experienced runners competed in a marathon race. The MLCK genotype (C37885A) of these marathoners was determined. Before and after the race, a sample of venous blood was obtained to assess changes in serum myoglobin concentrations and leg muscle power changes were measured during a countermovement jump. Self-reported leg muscle pain and fatigue were determined by questionnaires. A total of 59 marathoners (88.1%) were CC homozygotes and 8 marathoners (11.9%) were CA heterozygotes. The two groups of participants completed the race with a similar time (228 ± 33 vs 234 ± 39 min; P = 0.30) and similar self-reported values for fatigue (15 ± 2 vs 16 ± 2 A.U.; P = 0.21) and lower-limb muscle pain (6.2 ± 1.7 vs 6.6 ± 1.8 cm; P = 0.29). However, CC marathoners presented higher serum myoglobin concentrations (739 ± 792 vs 348 ± 144 μg·mL-1; P = 0.03) and greater pre-to-post- race leg muscle power reduction (-32.7 ± 15.7 vs -21.2 ± 21.6%; P = 0.05) than CA marathoners. CA heterozygotes for MLCK C37885A might present higher exercise-induced muscle damage after a marathon competition than CC counterparts
Interindividual variability in sweat electrolyte concentration in marathoners
Background: Sodium (Na+) intake during exercise aims to replace the Na+ lost by sweat to avoid electrolyteimbalances, especially in endurance disciplines. However, Na+ needs can be very different among individuals because of the great inter-individual variability in sweat electrolyte concentration. The aim of this investigation was to determine sweat electrolyte concentration in a large group of marathoners.
Methods: A total of 157 experienced runners (141 men and 16 women) completed a marathon race (24.4 ± 3.6 °C and 27.7 ± 4.8 % of humidity). During the race, sweat samples were collected by using sweat patches placed on the runners’ forearms. Sweat electrolyte concentration was measured by using photoelectric flame photometry.
Results: As a group, sweat Na+ concentration was 42.9 ± 18.7 mmol·L−1 (minimal-maximal value = 7.0–95.5 mmol·L−1), sweat Cl− concentration was 32.2 ± 15.6 mmol·L−1 (7.3–90.6 mmol·L−1) and sweat K+ concentration was 6.0 ± 0.9 mmol·L−1 (3.1–8.0 mmol·L−1). Women presented lower sweat Na+ (33.9 ± 12.1 vs 44.0 ± 19.1 mmol·L−1; P = 0.04) andsweat Cl− concentrations (22.9 ± 10.5 vs 33.2 ± 15.8 mmol·L−1; P = 0.01) than men. A 20 % of individuals presented asweat Na+ concentration higher than 60 mmol·L−1 while this threshold was not surpassed by any female marathoner.
Sweat electrolyte concentration did not correlate to sweat rate, age, body characteristics, experience or training.
Although there was a significant correlation between sweat Na+ concentration and running pace (r = 0.18; P = 0.03), this association was weak to interpret that sweat Na+ concentration increased with running pace.
Conclusions: The inter-individual variability in sweat electrolyte concentration was not explained by any individual characteristics except for individual running pace and sex. An important portion (20 %) of marathoners might need special sodium intake recommendations due to their high sweat salt losses
Application of a dynamic event tree methodolgy to steam generator tube rupture sequences
The Integrated Safety Assessment (ISA) methodology, developed by the Spanish Nuclear Safety Council (CSN), has been applied to a thermo-hydraulical analysis of a Westinghouse 3-loop PWR plant by means of the dynamic event trees (DET) for Steam Generator Tube Rupture (SGTR) sequences. The ISA methodology allows obtaining the SGTR Dynamic Event Tree taking into account the operator actuation times. Simulations are performed with SCAIS (Simulation Code system for Integrated Safety Assessment), which includes a dynamic coupling with MAAP thermal hydraulic code. The results show the capability of the ISA
methodology and SCAIS platform to obtain the DET of complex sequences
Automatic Structure Detection in Constraints of Tabular Data
Abstract. Methods for the protection of statistical tabular data—as controlled tabular adjustment, cell suppression, or controlled rounding— need to solve several linear programming subproblems. For large multi-dimensional linked and hierarchical tables, such subproblems turn out to be computationally challenging. One of the techniques used to reduce the solution time of mathematical programming problems is to exploit the constraints structure using some specialized algorithm. Two of the most usual structures are block-angular matrices with either linking rows (primal block-angular structure) or linking columns (dual block-angular structure). Although constraints associated to tabular data have intrin-sically a lot of structure, current software for tabular data protection neither detail nor exploit it, and simply provide a single matrix, or at most a set of smallest submatrices. We provide in this work an efficient tool for the automatic detection of primal or dual block-angular struc-ture in constraints matrices. We test it on some of the complex CSPLIB instances, showing that when the number of linking rows or columns is small, the computational savings are significant
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