1,066 research outputs found

    An Innovative Dynamic Test Method for Piles

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    The system described involves using solid propellant fuels to accelerate a reaction mass of the test pile. The force required to accelerate the reaction mass upwards acts equally downward on the pile. Very high forces be may applied to the pile in a controlled, linearly increasing manner. The duration of the applied load is approximately 100 milliseconds. This rate of loading is slow enough to allow the pile and soil to react together as a composite rigid body. The effects combine to produce pile and soil response no longer dominated by the transfer of force via stress pulse (as with impact). State of the art instrumentation systems are used to obtain test data. Displacement is monitored directly using a laser datum and integrated receiver located at the center axis of the pile. Force is also monitored directly using a calibrated load cell

    Species Composition and Distribution of Adult Anopheles (Diptera: Culicidae) in Panama

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    Anopheles (Diptera: Culicidae) species composition and distribution were studied using human landing catch data over a 35-yr period in Panama. Mosquitoes were collected from 77 sites during 228 Þeld trips carried out by members of the National Malaria Eradication Service. Fourteen Anopheles species were identiÞed. The highest average human biting rates were recorded from Anopheles (Nyssorhynchus) albimanus (Wiedemann) (9.8 bites/person/night) andAnopheles (Anopheles) punctimacula (Dyar and Knab) (6.2 bites/person/night). These two species were also the most common, present in 99.1 and 74.9%, respectively, of the sites. Anopheles (Nyssorhynchus) aquasalis (Curry) was encountered mostly in the indigenous Kuna Yala Comarca along the eastern Atlantic coast, where malaria case history and average human biting rate (9.3 bites/person/night) suggest a local role in malaria transmission. An. albimanus, An. punctimacula, and Anopheles (Anopheles) vestitipennis (Dyar and Knab) were more abundant during the rainy season (MayÐDecember), whereas An. aquasalis was more abundant in the dry season (JanuaryÐApril). Other vector species collected in this study were Anopheles (Kerteszia) neivai (Howard, Dyar, and Knab) and Anopheles (Anopheles) pseudopunctipenniss.l. (Theobald). High diversity of Anophelesspecies and six conÞrmed malaria vectors in endemic areas of Panama emphasize the need for more detailed studies to better understand malaria transmission dynamics.Anopheles (Diptera: Culicidae) species composition and distribution were studied using human landing catch data over a 35-yr period in Panama. Mosquitoes were collected from 77 sites during 228 Þeld trips carried out by members of the National Malaria Eradication Service. Fourteen Anopheles species were identiÞed. The highest average human biting rates were recorded from Anopheles (Nyssorhynchus) albimanus (Wiedemann) (9.8 bites/person/night) andAnopheles (Anopheles) punctimacula (Dyar and Knab) (6.2 bites/person/night). These two species were also the most common, present in 99.1 and 74.9%, respectively, of the sites. Anopheles (Nyssorhynchus) aquasalis (Curry) was encountered mostly in the indigenous Kuna Yala Comarca along the eastern Atlantic coast, where malaria case history and average human biting rate (9.3 bites/person/night) suggest a local role in malaria transmission. An. albimanus, An. punctimacula, and Anopheles (Anopheles) vestitipennis (Dyar and Knab) were more abundant during the rainy season (MayÐDecember), whereas An. aquasalis was more abundant in the dry season (JanuaryÐApril). Other vector species collected in this study were Anopheles (Kerteszia) neivai (Howard, Dyar, and Knab) and Anopheles (Anopheles) pseudopunctipenniss.l. (Theobald). High diversity of Anophelesspecies and six conÞrmed malaria vectors in endemic areas of Panama emphasize the need for more detailed studies to better understand malaria transmission dynamics

    Correlating Molecular Phylogeny with Venom Apparatus Occurrence in Panamic Auger Snails (Terebridae)

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    Central to the discovery of neuroactive compounds produced by predatory marine snails of the superfamily Conoidea (cone snails, terebrids, and turrids) is identifying those species with a venom apparatus. Previous analyses of western Pacific terebrid specimens has shown that some Terebridae groups have secondarily lost their venom apparatus. In order to efficiently characterize terebrid toxins, it is essential to devise a key for identifying which species have a venom apparatus. The findings presented here integrate molecular phylogeny and the evolution of character traits to infer the presence or absence of the venom apparatus in the Terebridae. Using a combined dataset of 156 western and 33 eastern Pacific terebrid samples, a phylogenetic tree was constructed based on analyses of 16S, COI and 12S mitochondrial genes. The 33 eastern Pacific specimens analyzed represent four different species: Acus strigatus, Terebra argyosia, T. ornata, and T. cf. formosa. Anatomical analysis was congruent with molecular characters, confirming that species included in the clade Acus do not have a venom apparatus, while those in the clade Terebra do. Discovery of the association between terebrid molecular phylogeny and the occurrence of a venom apparatus provides a useful tool for effectively identifying the terebrid lineages that may be investigated for novel pharmacological active neurotoxins, enhancing conservation of this important resource, while providing supplementary information towards understanding terebrid evolutionary diversification

    Bias, accuracy, and impact of indirect genetic effects in infectious diseases

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    Selection for improved host response to infectious disease offers a desirable alternative to chemical treatment but has proven difficult in practice, due to low heritability estimates of disease traits. Disease data from field studies is often binary, indicating whether an individual has become infected or not following exposure to an infectious disease. Numerous studies have shown that from this data one can infer genetic variation in individuals’ underlying susceptibility. In a previous study, we showed that with an indirect genetic effect (IGE) model it is possible to capture some genetic variation in infectivity, if present, as well as in susceptibility. Infectivity is the propensity of transmitting infection upon contact with a susceptible individual. It is an important factor determining the severity of an epidemic. However, there are severe shortcomings with the Standard IGE models as they do not accommodate the dynamic nature of disease data. Here we adjust the Standard IGE model to (1) make expression of infectivity dependent on the individuals’ disease status (Case Model) and (2) to include timing of infection (Case-ordered Model). The models are evaluated by comparing impact of selection, bias, and accuracy of each model using simulated binary disease data. These were generated for populations with known variation in susceptibility and infectivity thus allowing comparisons between estimated and true breeding values. Overall the Case Model provided better estimates for host genetic susceptibility and infectivity compared to the Standard Model in terms of bias, impact, and accuracy. Furthermore, these estimates were strongly influenced by epidemiological characteristics. However, surprisingly, the Case-Ordered model performed considerably worse than the Standard and the Case Models, pointing toward limitations in incorporating disease dynamics into conventional variance component estimation methodology and software used in animal breeding

    Randomised controlled trial and health economic evaluation of the impact of diagnostic testing for influenza, respiratory syncytial virus and Streptococcus pneumoniae infection on the management of acute admissions in the elderly and high-risk 18- to 64-year-olds

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    Please cite the published version which is available via the DOI link in this record.Western industrialised nations face a large increase in the number of older people. People over the age of 60 years account for almost half of the 16.8 million hospital admissions in England from 2009 to 2010. During 2009-10, respiratory infections accounted for approximately 1 in 30 hospital admissions and 1 in 20 of the 51.5 million bed-days.HTA ProgrammeNational Institute for Health Research (NIHR

    Grain refinement of wire arc additively manufactured titanium by the addition of silicon

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    This study demonstrates that silicon additions are effective in refining the microstructure of additive layer manufactured (ALM) titanium components. The addition of up to 0.75 wt% silicon to commercially pure titanium manufactured by wire arc ALM results in a significant reduction of the prior-β grain size. It is observed that silicon also reduces the width of the columnar grains and allows for the nucleation of some equiaxed grains through the development of constitutional supercooling and growth restriction. The grain size of the ALM components is compared to a casting process and it is found that the as-deposited microstructure produced during ALM exhibits larger average grain sizes. Using the Interdependence model for predicting grain size, it was determined that the population of nucleant particles that naturally occur in titanium, has comparable potency (i.e. ability to activate at a similar undercooling) regardless of the processing method, however, the ALM process contains fewer, sufficiently potent, nucleant particles than for the casting process due to the effect of subsequent cycles of remelting and heating
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