2,118 research outputs found
NNEP: The Navy NASA Engine Program
A computer code capable of simulating almost any conceivable turbine engine is described. This code uses stacked component maps and multiple flowpaths to simulate variable cycle engines with variable component geometry. It is capable of design and off-design (matching) calculations and can optimize free variables such as nozzle areas to minimize specific fuel consumption
Estimating sustainable yield from biomass and harvest rates: what are the appropriate approaches for tropical species with high values of M?
Fisheries thematic mapping : a prerequisite for intelligent management and development of fisheries
Le document discute la pertinence de la cartographie thématique dans le contexte général de l'halieutique et indique l'importance de la cartographie des ressources, en particulier dans les ZEE des pays en développement. La perspective historique du développement de la science halieutique dans les zones de pêches traditionnelles confirme que la cartographie des ressources est une première et importante étape de l'évaluation des stocks, particulièrement dans la zone côtière. Certaines méthodes d'évaluation découlant directement de cette cartographie sont mentionnées, ainsi que les dangers d'une utilisation abusive de modèles supposant que les hypothèses d'homogénéité s'appliquent à des populations géographiquement grégaires et sous-dispersées. Le document passe en revue les diverses considérations spatiales qui affectent les divers types d'analyses effectuées sur les pêcheries. On y propose quelques critères et une classification grossière des divers types d'application de la cartographie aux pêches, y compris leur utilisation pour la pêche exploratoire, les prospections des navires de recherche, les systèmes de collecte des statistiques, la préparation des plans d'aménagement, l'allocation de l'espace maritime pour l'aquaculture, l'aménagement du littoral et les études d'impact, les négociations concernant les frontières maritimes et les accords de pêche. La périodicité de la mise à jour des cartes varie selon les applications. Dans certains cas, le principal souci doit être la facilité de mise à jour plutôt qu'une grande précision dont la nécessité est souvent limitée par les capacités de positionnement des petits bateaux de pêche. Le document insiste, enfin, sur la nécessité de promouvoir l'application en routine de technologies telles que les microordinateurs et la télédétection, ainsi que l'élaboration de logiciels pour l'établissement et la mise à jour rapide des cartes thématiques. (Résumé d'auteur
Alcohol Breath Tests: Criterion Times for Avoiding Contamination by “Mouth Alcohol”
Using either a gas chromatography or an infrared absorption technique, series of blood alcohol concentrations (BACs) determined by breath tests were obtained from human subjects immediately subsequent to their having only oral contact with beverages ranging in ethyl alcohol concentration from 4% to 95% +. Times for total dissipation of mouth alcohol residuals to a level of practical nonsignificance ranged from 10 to 19 min. Dissipation rates were an inverse and approximately exponential function of the ethyl alcohol concentration of the beverage and were greatly shortened by rinsing the mouth with warm (34°C) water prior to testing. The results are discussed in terms of their relevance to the methodology of a number of research studies employing BAC breath-testing equipment
Effects of saddle angle on heavy intensity time trial cycling: Implications of the UCI rule 1.3.014
The UCI dictates that during sanctioned events, the saddle of the bicycle may be at angle of no more than 3° of forward rotation, so as to prevent performance advantages (Rule 1.3.014). This research investigates the effect on performance when rotating the saddle beyond the mandated angle during a laboratory 4km time trial (TT). Eleven competitive male cyclists (age 26±6 (mean±SD) yrs, height 179.2±6.7 cm, body mass 72.5±6.7 kg; V̇O2max 70.9±8.6 ml∙kg-1∙min-1) completed laboratory 4km TTs using saddle angles of 0°, 3° and 6°. Completion time and mean power were recorded, in addition to lower appendage kinematics, crank torque kinetics and cardiorespiratory responses. There were no significant changes in TT time, power output, cardiorespiratory variables or crank torque kinetics as a function of saddle angle (P>0.05). There were significant effects on minimum and maximum hip angle and the horizontal displacement of the greater trochanter (P<0.05). At 6° the maximum hip angle and forward displacement of the greater trochanter was greater compared to 0° and 3°. Minimum hip angle was greater at 6° than 3° (P<0.05). In conclusion, contravening UCI rule 1.3.014 by using a saddle angle beyond 3° does not result in performance advantages during a laboratory 4 km. However, tilting the saddle does appear to cause a forward displacement of the pelvis leading to an opening of the hip angle at the top and bottom of the pedal stroke
The effects of forward rotation of posture on heavy intensity cycling: Implications of UCI rule 1.3.013
UCI rule 1.3.013 limits the forward displacement of the nose of the saddle to 5cm rearward of the centre of the bottom-bracket. This study tests the effects of contravening this rule on 4km laboratory time trials and highlights biomechanical and physiological responses that could be of interest to coaches and bike fitters. Ten competitive male cyclists age 26±2 (mean±SD) yrs, height 180±5 cm, body mass 71±6 kg; V̇ O2max 70.9±8.6 ml·kg-1·min-1) completed 4km time trials and heavy intensity bouts. Riding posture was rotated forward where the nose of the saddle was 0, 2, 4, and 6cm to the rear of the bottom bracket (P0, P2, P4 and P6). End time, power, cardiorespiratory responses, lower appendage kinematics and crank torque kinetics were measured. There was no significant effect of position on 4 km time trials completion time or power. During 4 km time trials and heavy intensity bouts, gas exchange variables and lower limb range of motion were unchanged (P>0.05). Trunk lean angle, cardiac output and stroke volume were greater at P6 than other positions (P0.05). Results indicate, contravening rule 1.3.013 does not bring about improvements to 4km laboratory TTs. The rearward shift in peak crank torque most likely occurs as a function of altered muscle activation. Haemodynamic variations are possibly related to changes in peripheral resistance at the most forward position. Further work is necessary to allude to probable improvements in aerodynamics
Multispecies fisheries management in the Mediterranean Sea: application of the Fcube methodology
Genogroup IV and VI canine noroviruses interact with histo-blood group antigens.
UNLABELLED: Human noroviruses (HuNV) are a significant cause of viral gastroenteritis in humans worldwide. HuNV attaches to cell surface carbohydrate structures known as histo-blood group antigens (HBGAs) prior to internalization, and HBGA polymorphism among human populations is closely linked to susceptibility to HuNV. Noroviruses are divided into 6 genogroups, with human strains grouped into genogroups I (GI), II, and IV. Canine norovirus (CNV) is a recently discovered pathogen in dogs, with strains classified into genogroups IV and VI. Whereas it is known that GI to GIII noroviruses bind to HBGAs and GV noroviruses recognize terminal sialic acid residues, the attachment factors for GIV and GVI noroviruses have not been reported. This study sought to determine the carbohydrate binding specificity of CNV and to compare it to the binding specificities of noroviruses from other genogroups. A panel of synthetic oligosaccharides were used to assess the binding specificity of CNV virus-like particles (VLPs) and identified α1,2-fucose as a key attachment factor. CNV VLP binding to canine saliva and tissue samples using enzyme-linked immunosorbent assays (ELISAs) and immunohistochemistry confirmed that α1,2-fucose-containing H and A antigens of the HBGA family were recognized by CNV. Phenotyping studies demonstrated expression of these antigens in a population of dogs. The virus-ligand interaction was further characterized using blockade studies, cell lines expressing HBGAs, and enzymatic removal of candidate carbohydrates from tissue sections. Recognition of HBGAs by CNV provides new insights into the evolution of noroviruses and raises concerns regarding the potential for zoonotic transmission of CNV to humans. IMPORTANCE: Infections with human norovirus cause acute gastroenteritis in millions of people each year worldwide. Noroviruses can also affect nonhuman species and are divided into 6 different groups based on their capsid sequences. Human noroviruses in genogroups I and II interact with histo-blood group antigen carbohydrates, bovine noroviruses (genogroup III) interact with alpha-galactosidase (α-Gal) carbohydrates, and murine norovirus (genogroup V) recognizes sialic acids. The canine-specific strains of norovirus are grouped into genogroups IV and VI, and this study is the first to characterize which carbohydrate structures they can recognize. Using canine norovirus virus-like particles, this work shows that representative genogroup IV and VI viruses can interact with histo-blood group antigens. The binding specificity of canine noroviruses is therefore very similar to that of the human norovirus strains classified into genogroups I and II. This raises interesting questions about the evolution of noroviruses and suggests it may be possible for canine norovirus to infect humans.The authors would like to thank Wood Green Animal Shelter for allowing SC to collect canine saliva samples, and Dr. Nathalie Ruvoën-Clouet and Béatrice Vaidye for the preparation of the anti-CNV antibodies. The authors also thank Dr. Takane Katayama (Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan) for his generous gift of 1,2fucosidase and the Cellular and Tissular Imaging core facility of the Nantes University (MicroPiCell). This collaborative project was greatly facilitated by the Society of Microbiology’s President’s Fund awarded to SC and by the Region des Pays de la Loire ARMINA project. This work was supported by a PhD studentship from the Medical Research Council to SC and a Wellcome Trust Senior Fellowship to IG (Ref: WT097997MA). IG is a Wellcome Senior Fellow.This is the final published version. It's also available from ASM at http://jvi.asm.org/content/88/18/10377.long
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