7,838 research outputs found
Updated Performance of the T-Seeding
Improvements to the performance of the track seeding since the start of the DC '06 data challenge are described. For tracks above 2~GeV an efficiency of is achieved for a ghost rate of 8.1~\%. In addition, the expected performance of the algorithm during the 2007 pilot run is discussed
Association between match activity variables, measures of fatigue and neuromuscular performance capacity following elite competitive soccer matches
The aim of the study was to assess the relationships between match activity variables, subsequent fatigue and neuromuscular performance capacity in elite soccer players. Subjects (n = 10) were professional soccer players participating in the English Championships. Match activity variables and markers of fatigue status were measured before and following two matches. Creatine kinase (CK) and muscle soreness were measured at baseline, immediately following, as well as 40 and 64 h post-match. Countermovement jump performance and perceived ratings of wellness were measured at baseline, then 40 and 64 h post-match. Relationships were shown between CK and the total number of accelerations and decelerations immediately (r = 0.63; large), 40 h (r = 0.45; moderate) and 64 h post-match (r = 0.35; moderate) (p < 0.05). Relationships between CK and total sprint distance (r = 0.39; moderate) and the number of sprints (r = 0.35; moderate) 40 h post-match (p < 0.05) were observed. Furthermore, relationships were shown between the perceived rating of wellness and number of accelerations 40 (r = 0.52; large) and 64 h (r = 0.40; moderate) post-match, sprint distance 40 h post-match (r = 0.40; moderate) and the total number of sprints 40 h post-match (r = 0.51; large) (p < 0.05). The quantification of match activity variables, particularly the total number of accelerations and decelerations and the number of sprints, provides insights into the fatigue status in elite soccer players 40 and 64 h post-match
Standalone Track Reconstruction in the T-stations
An algorithm for fast and efficient tracking in the T-stations is describedtogether with its performance in the DC06 data challenge. An efficiency of94-- is achieved for tracks with momenta above 2~GeV for a ghost rate of
Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy
International audienceBy controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C) containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate) proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine) and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments
Applicability and Utility of the Astromaterials X-Ray Computed Tomography Laboratory at Johnson Space Center
The Astromaterials Acquisition and Curation Office at NASAs Johnson Space Center is responsible for curating all of NASAs astromaterial sample collections (i.e. Apollo samples, Luna Samples, Antarctic Meteorites, Cosmic Dust Particles, Microparticle Impact Collection, Genesis solar wind atoms, Stardust comet Wild-2 particles, Stardust interstellar particles, and Hayabusa asteroid Itokawa particles) [1-3]. To assist in sample curation and distribution, JSC Curation has recently installed an X-ray computed tomography (XCT) scanner to visualize and characterize samples in 3D. [3] describes the instrumental set-up and the utility of XCT to astromaterials curation. Here we describe some of the current and future projects and illustrate the usefulness of XCT in studying astromaterials
Using ordinary multiplication to do relativistic velocity addition
Relativistic addition of velocities in one dimension, though a mainstay of
introductory physics, contributes much less physical insight than it could. For
such calculations, we propose the use of velocity factors (two-way doppler
factors). Velocities can easily, often by inspection, be turned into velocity
factors, and vice versa. Velocity factors compose by ordinary multiplication.
This simple device considerably extends the kinds of questions that can be
asked and answered in an introductory course.Comment: 6 page
Surveillance for Toxoplasma gondii in the white-tailed deer (Odocoileus virginianus) in Ohio
Author Institution: Department of Entomology, The Ohio State UniversitySerum samples from 147 white-tailed deer, Odocoileus virginianus, were collected at deer-check stations and Columbus area metropolitan park deer hunts during November and December of Ohio's 1996-97 and 97-98 hunting seasons. These samples were tested for Toxoplasma gondii antibodies using a modified direct agglutination assay. Forty-four percent (65/147) of the samples tested positive. Sixteen percent had a titer of 25, 16% had a titer of 50, 3% had a titer of 250 and 9% had a titer of >500. Percentage of positive deer varied greatly between geographical locations. Fifty-five percent of 45 serum samples collected from Hocking County were positive while only 6% of the 18 deer sampled from Franklin County tested positive. No significant differences in infection rates were observed between sexes. This is the first report of T. gondii antibodies from a game animal in Ohio. Pregnant women should thoroughly cook venison before it is consumed to avoid complications from this pathogen
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