915 research outputs found
CHANDRA Observations of X-ray Jet Structure on kpc to Mpc Scales
With its exquisite spatial resolution of better than 0.5 arcsecond, the
Chandra observatory is uniquely capable of resolving and studying the spatial
structure of extragalactic X-ray jets on scales of a few to a few hundred
kilo-parsec. Our analyses of four recent Chandra images of quasar jets
interpret the X-ray emission as inverse Compton scattering of high energy
electrons on the cosmic microwave background. We infer that these jets are in
bulk relativistic motion, carrying kinetic powers upwards of 10^46 ergs/s to
distances of hundreds of kpc, with very high efficiency.Comment: 4 pages, 3 figures, to be published in the proceedings of the Bologna
jet workshop, "The Physics of Relativistic Jets in the CHANDRA and XMM Era.
AFRICAN INDIGENOUS AND TRADITIONAL VEGETABLES IN TANZANIA: PRODUCTION, POST-HARVEST MANAGEMENT AND MARKETING
Indigenous and traditional African vegetables (AITVs) are important
sources of nutrition for sub-Saharan Africans (SSA), especially the
low-income and food insecure. The U.S. Agency for International
Development directed Horticulture Collaborative Research Support
Program, now named the Horticulture Innovation Lab, builds
international partnerships for fruit and vegetable research to improve
livelihoods in developing countries. For this Programme a study was
carried out to provide baseline information on AITVs in Tanzania and to
determine research needs. A questionnaire-based survey was conducted in
four regions of Tanzania with a total of 160 sellers and producers of
AITVs, with attention to post-harvest management. Key concerns were
demographics, i.e. who is growing, transporting, and selling AITVs,
AITV identities and quantities, production, harvest, transport,
wholesale and retail patterns, processing, and surplus. Common AITVs
are greens of amaranths, nightshade, cowpea, cucurbits, Ipomea ,
cassava tree, spider flower and Ethiopian mustard; plus African
eggplant and okra fruits. Ninety six percent of sellers and 71% of
producers were female. Most AITVs are sold in roofed open markets,
secondarily on streets by mobile or semi-mobile sellers. Amaranth was
the number one seller for 83% of sellers. Issues covered were: (i)
cultural practices, AITV plot size, seed sources, irrigation and
pesticide use; (ii) post-harvest: harvest to market storage and
transport times and modes, grading, packaging and bundling, and
washing; and (iii) marketing: retail markup, price variation by season,
year and region, average daily sales; cell phone use, retail space size
and cost, retailer storage, remainders, processing and less common
AITVs. OLS regression was done to elucidate factors affecting sales
volume and regional differences. Post-harvest losses of AITVs do not
appear to be significant as the value chain participants demonstrate an
acute knowledge of consumer demand and daily market dynamics.Les l\ue9gumes indig\ue8nes et traditionnelles africaines (AITVs)
constituent une source importante de nutrition pour l\u2019Afrique
sub-saharienne, sp\ue9cialement \ue0 bas revenus et \ue0
ins\ue9curit\ue9 alimentaire. Le programme de soutien \ue0 la
recherche collaborative de l\u2019agence internationale
am\ue9ricaine pour le d\ue9veloppement, aussi appel\ue9
\u2018Horticulture Innovation Lab\u2019 institue des partenariats
internationaux pour la recherche sur les fruits et les l\ue9gumes
pour am\ue9liorer les conditions de vie dans les pays en voie de
d\ue9veloppement. Une \ue9tude \ue9tait conduite afin
d\u2019\ue9tablir une information de base sur AITVs en Tanzanie et
d\ue9terminer les besoins en recherche. Une enqu\ueate \ue9tait
conduite dans quatre r\ue9gions de la Tanzanie avec un total de 160
vendeurs et producteurs de AITVs, avec attention \ue0 la gestion
post-r\ue9colte. La question la plus importante concernait la
d\ue9mographie, par exemple, qui cro\ueet, transporte et vend AITV,
identit\ue9s et quantit\ue9s de l\u2019AITV, production,
r\ue9colte, transport, grossistes et d\ue9taillants, transformation
et surplus. Les AITVs usuels sont des amarantes, morelles, pois cajan,
cucurbites, Ipomea , manioc, cl\ue9ome et moutarde \ue9thiopienne.
A ceci s\u2019ajoute les aubergines africaines et les fruits
d\u2019Okra. Quatre vingt seize pour cent des vendeurs et 71% des
producteurs \ue9taient des femmes. La plupart d\u2019AITVs sont
vendus dans des march\ue9s t\uf4l\ue9s ouverts sur les rues par
des vendeurs mobiles ou semi-mobiles. Les amarantes \ue9taient les
plus vendues (83%). Les probl\ue8mes rencontr\ue9s \ue9taient:
(i) pratiques culturales, la taille des parcelles sous AITV, sources
des semences, utilisation des pesticides et de l\u2019irrigation; (ii)
post-r\ue9colte: de la r\ue9colte au magasin du march\ue9 et
temps et mode de transport, cat\ue9gorisation, emballage et
empaquetage, et le lavage, et (iii) promotion sur le march\ue9:
fixation des prix des d\ue9tails, variation des prix par saison,
ann\ue9e et r\ue9gion, ventes moyennes journali\ue8res,
utilisation des t\ue9l\ue9phone cellulaires, la taille et le
co\ufbt de l\u2019espace pour vente des produits, le magasin des
petits vendeurs, les produits restants apr\ue8s vente, la
transformation et les AITVs les moins communs. La r\ue9gression
d\u2019OLS \ue9tait faite apr\ue8s vente pour \ue9lucider les
facteurs qui affectent le volume des ventes et les diff\ue9rences
r\ue9gionales. Des pertes post-r\ue9coltes d\u2019AITVs ne
paraissent pas \ueatre significatives \ue9tant donn\ue9 que les
participants dans la chaine des valeurs font montre d\u2019une
connaissance suffisante sur la demande du consommateur et les
dynamiques quotidiennes du march\ue9
The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in United States high school football (2005-2006 through 2013-2014) and National collegiate athletic association football (2004-2005 through 2013-2014)
Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of football injury data. Objective: To describe the epidemiology of injuries sustained in high school football in the 2005-2006 through 2013-2014 academic years and collegiate football in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from football teams of high school boys (annual average ¼ 100) and collegiate men (annual average ¼ 43). Patients or Other Participants: Football players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected time-loss injury (24 hours) and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online system documented 18 189 time-loss injuries during 4 539 636 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 22 766 time-loss injuries during 3 121 476 AEs. The injury rate was higher among collegiate than high school (7.29 versus 4.01/1000 AEs; IRR ¼ 1.82; 95% CI ¼ 1.79, 1.86) athletes. Most injuries occurred during competitions in high school (53.2%) and practices in college (60.9%). The competition injury rate was higher than the practice injury rate among both high school (IRR ¼ 5.62; 95% CI ¼ 5.46, 5.78) and collegiate (IRR ¼ 6.59; 95% CI ¼ 6.41, 6.76) players. Most injuries at both levels affected the lower extremity and the shoulder/clavicle and were diagnosed as ligament sprains and muscle/tendon strains. However, concussion was a common injury during competitions among most positions. Conclusions: Injury rates were higher in college than in high school and higher for competitions than for practices. Concussion was a frequent injury sustained during competitions, which confirms the need to develop interventions to mitigate its incidence and severity
Search for Small Trans-Neptunian Objects by the TAOS Project
The Taiwan-America Occultation Survey (TAOS) aims to determine the number of
small icy bodies in the outer reach of the Solar System by means of stellar
occultation. An array of 4 robotic small (D=0.5 m), wide-field (f/1.9)
telescopes have been installed at Lulin Observatory in Taiwan to simultaneously
monitor some thousand of stars for such rare occultation events. Because a
typical occultation event by a TNO a few km across will last for only a
fraction of a second, fast photometry is necessary. A special CCD readout
scheme has been devised to allow for stellar photometry taken a few times per
second. Effective analysis pipelines have been developed to process stellar
light curves and to correlate any possible flux changes among all telescopes. A
few billion photometric measurements have been collected since the routine
survey began in early 2005. Our preliminary result of a very low detection rate
suggests a deficit of small TNOs down to a few km size, consistent with the
extrapolation of some recent studies of larger (30--100 km) TNOs.Comment: 4 pages, 3 figures, IAU Symposium 23
Lower Extremity Musculoskeletal Injury in US Military Academy Cadet Basic Training: A Survival Analysis Evaluating Sex, History of Injury, and Body Mass Index
Background: Injury incidence for physically active populations with a high volume of physical load can exceed 79%. There is little existing research focused on timing of injury and how that timing differs based on certain risk factors. Purpose/Hypothesis: The purpose of this study was to report both the incidence and timing of lower extremity injuries during cadet basic training. We hypothesized that women, those with a history of injury, and those in underweight and obese body mass index (BMI) categories would sustain lower extremity musculoskeletal injury earlier in the training period than men, those without injury history, and those in the normal-weight BMI category. Study Design: Cohort study; Level of evidence, 2. Methods: Cadets from the class of 2022, arriving in 2018, served as the study population. Baseline information on sex and injury history was collected via questionnaire, and BMI was calculated from height and weight taken during week 1 at the United States Military Academy. Categories were underweight (BMI <20), middleweight (20-29.99), and obese (≥30). Injury surveillance was performed over the first 60 days of training via electronic medical record review and monitoring. Kaplan-Meier survival curves were used to estimate group differences in time to the first musculoskeletal injury. Cox proportional hazard regression was used to estimate hazard ratios (HRs). Results: A total of 595 cadets participated. The cohort was 76.8% male, with 29.9% reporting previous injury history and 93.3% having a BMI between 20 and 30. Overall, 16.3% of cadets (12.3% of male cadets and 29.7% of female cadets) experienced an injury during the follow-up period. Women experienced significantly greater incident injury than did men (P <.001). Separation of survival curves comparing the sexes and injury history occurred at weeks 3 and 4, respectively. Hazards for first musculoskeletal injury were significantly greater for women versus men (HR, 2.63; 95% CI, 1.76-3.94) and for those who reported a history of injury versus no injury history (HR, 1.76; 95% CI, 1.18-2.64). No differences were observed between BMI categories. Conclusion: Female cadets and those reporting previous musculoskeletal injury demonstrated a greater hazard of musculoskeletal injury during cadet basic training. This study did not observe an association between BMI and injury
Cosmic-ray strangelets in the Earth's atmosphere
If strange quark matter is stable in small lumps, we expect to find such
lumps, called ``strangelets'', on Earth due to a steady flux in cosmic rays.
Following recent astrophysical models, we predict the strangelet flux at the
top of the atmosphere, and trace the strangelets' behavior in atmospheric
chemistry and circulation. We show that several strangelet species may have
large abundances in the atmosphere; that they should respond favorably to
laboratory-scale preconcentration techniques; and that they present promising
targets for mass spectroscopy experiments.Comment: 28 pages, 4 figures, revtex
The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in us high school girls' volleyball (2005-2006 through 2013-2014) and national collegiate athletic association women's volleyball (2004-2005 Through 2013-2014)
Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided in the acquisition of girls' and women's volleyball injury data. Objective: To describe the epidemiology of injuries sustained in high school girls' volleyball in the 2005-2006 through 2013-2014 academic years and collegiate women's volleyball in the 2004-2005 through 2013-2014 academic years using Webbased sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from high school girls' (annual average=100) and collegiate women's (annual average = 50) volleyball teams. Patients or Other Participants: Girls' and women's volleyball players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school and the 2004-2005 through 2013-2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected timeloss (≥24 hours) injury and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online system documented 1634 time-loss injuries during 1 471 872 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2149 time-loss injuries during 563 845 AEs. The injury ratewas higher in college than in high school (3.81/ 1000 versus 1.11/1000 AEs; IRR=3.43; 95%CI=3.22, 3.66), and higher in high schools with ≤1000 students than in those with >1000 students (IRR=1.35; 95% CI=1.23, 1.49). Injury rates did not vary by collegiate division. The injury rate was higher during competitions than practices for high school (IRR=1.23; 95% CI= 1.12, 1.36) but not for college (IRR= 1.01; 95% CI= 0.92, 1.10). Ankle sprains were common in both the high school and collegiate setting. However, liberos had a high incidence of concussion. Conclusions: Injury rates were higher among collegiate than high school players. However, injury rates differed by event type in high school, unlike college. Concussion injury patterns among liberos varied from those for other positions. These findings highlight the need for injury-prevention interventions specific to setting and position
The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boys' ice hockey (2008-2009 through 2013-2014) and National Collegiate Athletic Association men's and women's ice hockey (2004-2005 through 2013-2014)
Context: Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided efforts to collect data on ice hockey injuries. Objective: To describe the epidemiology of injuries sustained in high school boy's ice hockey in the 2008-2009 through 2013-2014 academic years and collegiate men's and women's ice hockey in the 2004-2005 through 2013-2014 academic years using Web-based surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance of ice hockey teams of high school boys (annual average ¼ 34), collegiate men (annual average ¼ 20), and collegiate women (annual average ¼ 11). Patients or Other Participants: Boys', men's, and women's ice hockey players who participated in practices and competitions during the 2008-2009 through 2013-2014 high school academic years or the 2004-2005 through 2013-2014 collegiate academic years. Main Outcome Measure(s): Athletic trainers collected time-loss (24 hours) injury and exposure data. We calculated injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis. Results: The High School Reporting Information Online system documented 831 boys' ice hockey time-loss injuries during 356 997 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2611 men's ice hockey time-loss injuries during 552 642 AEs and 752 women's ice hockey injuries during 232 051 AEs. Injury rates were higher in collegiate men than in high school boys during 2008-2009 through 2013-2014 (4.38 versus 2.33/1000 AEs; IRR ¼ 1.88; 95% CI ¼ 1.73, 2.05) and collegiate women during 2004-2005 through 2013-2014 (IRR ¼ 1.46; 95% CI ¼ 1.34, 1.58). Most injuries occurred during competitions (boys ¼ 80.0%, men ¼ 66.9%, women ¼ 55.3%); injury rates were higher in competitions than in practices for boys (IRR ¼ 8.14; 95% CI ¼ 6.87, 9.65), men (IRR ¼ 6.58; 95% CI ¼ 6.06, 7.13), and women (IRR ¼ 3.63; 95% CI ¼ 3.14, 4.19). At all levels, most injuries occurred to the head/face and shoulder/clavicle and resulted in concussions, contusions, or ligament sprains. Conclusions: Injury rates varied across sports but were consistently higher in competitions than in practices. In competitions, concussions were common injuries, highlighting the need for continued development of injury-prevention strategies
The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boys' wrestling (2005-2006 through 2013-2014) and National Collegiate Athletic Association Men's Wrestling (2004-2005 through 2013-2014)
Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of wrestling injury data. Objective: To describe the epidemiology of injuries sustained in high school boys' wrestling in the 2005-2006 through 2013-2014 academic years and collegiate men's wrestling in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from wrestling teams of high school boys (annual average ¼ 100) and collegiate men (annual average ¼ 11). Patients or Other Participants: Male wrestlers who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected time-loss (24 hours) injuries and exposure data during this time period. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios with 95% confidence intervals, and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online documented 3376 time-loss injuries during 1 416 314 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2387 time-loss injuries during 257 297 AEs. The total injury rate was higher in college than in high school (9.28 versus 2.38/1000 AEs; injury rate ratio ¼ 3.89; 95% confidence interval ¼ 3.69, 4.10). In high school, the most commonly injured body parts for both practices and competitions were the head/face (practices ¼ 19.9%, competitions ¼ 21.4%) and shoulder/clavicle (practices ¼ 14.1%, competitions ¼ 21.0%). In college, the most frequently injured body parts for both practices and competitions were the knee (practices ¼ 16.7%, competitions ¼ 30.4%) and head/face (practices ¼ 12.1%, competitions ¼ 14.6%). Conclusions: Injury rates were higher in collegiate than in high school players, and the types of injuries sustained most often differed. Based on these results, continued study of primary and secondary prevention of injury in wrestlers across levels of competition is warranted
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