Protein synthesis in Plasmodium falciparum gametocytes cultured in vitro

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Accounting for multivariate probabilities of failure in vertical seawall reliability assessments

The aim of this paper is to appraise the current knowledge on seawall performance and reliability, and to make the case for improved reliability assessments of vertical seawalls, which are used here as a representative for coastal flood defences. In order to achieve this aim, a brief introduction to flood risk management is first given. Then, vertical seawalls are introduced, and their most prominent failure modes are discussed. Reliability analysis is introduced within the context of flood risk management. More specifically, the fragility curve approach that is currently in use in industry is described, and its limitations are discussed. Finally, it is argued that recent advances in multivariate extreme value models would enable improvements to the approaches currently applied in practice. It is stressed that future risk assessment models of coastal flood defences ought to include multiple failure modes and their interactions, a thorough analysis of the model uncertainties, and potential computational costs, in view of providing practitioners with an improved and functional risk assessment tool. Carter, Magar, Simm, Gouldby & Walli

Effects of index selection on the carcass composition of sheep given either ad libitum or controlled amounts of food

Sheep of a line (S) selected on an index to increase lean weight and decrease fatness at an age, and a control line (C), were given a high quality food at different levels including ad libitum. Live performance was measured from about 21 to 114 kg live weight, The carcasses of each line were analysed for lean, fat and bone at three widely varying weights in both males and females. Level of feeding did not affect the extent to which S was superior to C in either the level of fatness in the carcass (0·86 as much) or the ratio of lean tofat (1·28 as much). The lean to bone ratio was slightly greater in S (1·028 of the value of C; P \u3c 0,05) and was higher on the lowest level of feeding compared with the two higher levels used (P \u3c 0·05 in one experiment on females and P \u3c 0,001 in another on males). On ad libitum feeding the S line grew 1·19 times as fast and was 1·17 times as efficient compared with C. These advantages to S decreased as level of feeding decreased to become virtually zero at the lowest level of feeding used, which allowed C to grow at only 0·53 of the rate seen on ad libitum feeding. On ad libitum feeding growth was well described by a Gompertz growth function of the form W= (Z/B) exp(-exp (Go -8 t)). The maximum growth rate is (Z/e). Line S had a value of 2 that was 1·10 that of C averaged across the two sexes. A Spillman function W= Wo+ (A-WO) (l-exp (-k F)) was used to describe weight, W, in terms of cumulative intake, F. It worked well for ad libitum feeding andfor the two restricted regimes used. The value of the combined parameter (A k) varied across treatments in the same wayas efficiency did

Effects of index selection on the carcass composition of sheep given either ad libitum or controlled amounts of food

Sheep of a line (S) selected on an index to increase lean weight and decrease fatness at an age, and a control line (C), were given a high quality food at different levels including ad libitum. Live performance was measured from about 21 to 114 kg live weight, The carcasses of each line were analysed for lean, fat and bone at three widely varying weights in both males and females. Level of feeding did not affect the extent to which S was superior to C in either the level of fatness in the carcass (0·86 as much) or the ratio of lean tofat (1·28 as much). The lean to bone ratio was slightly greater in S (1·028 of the value of C; P \u3c 0,05) and was higher on the lowest level of feeding compared with the two higher levels used (P \u3c 0·05 in one experiment on females and P \u3c 0,001 in another on males). On ad libitum feeding the S line grew 1·19 times as fast and was 1·17 times as efficient compared with C. These advantages to S decreased as level of feeding decreased to become virtually zero at the lowest level of feeding used, which allowed C to grow at only 0·53 of the rate seen on ad libitum feeding. On ad libitum feeding growth was well described by a Gompertz growth function of the form W= (Z/B) exp(-exp (Go -8 t)). The maximum growth rate is (Z/e). Line S had a value of 2 that was 1·10 that of C averaged across the two sexes. A Spillman function W= Wo+ (A-WO) (l-exp (-k F)) was used to describe weight, W, in terms of cumulative intake, F. It worked well for ad libitum feeding andfor the two restricted regimes used. The value of the combined parameter (A k) varied across treatments in the same wayas efficiency did

Detection of hepatitis C virus in the nasal secretions of an intranasal drug-user

BACKGROUND: One controversial source of infection for hepatitis C virus (HCV) involves the sharing of contaminated implements, such as straws or spoons, used to nasally inhale cocaine and other powdered drugs. An essential precondition for this mode of transmission is the presence of HCV in the nasal secretions of intranasal drug users. METHODS: Blood and nasal secretion samples were collected from five plasma-positive chronic intranasal drug users and tested for HCV RNA using RT-PCR. RESULTS: HCV was detected in all five blood samples and in the nasal secretions of the subject with the highest serum viral load. CONCLUSIONS: This study is the first to demonstrate the presence of HCV in nasal secretions. This finding has implications for potential transmission of HCV through contact with contaminated nasal secretions

Responses to selection for lean growth in sheep

This paper reports the selection responses achieved, and related results, following 9 years of index selection for lean growth in Suffolk sheep. The breeding goal of the index used comprised carcass lean weight and carcass fat weight at a constant age, with relative economic values of + 3 and –1 per kg. The selection criteria were live weight (LWT), ultrasonic fat depth (UFD) and ultrasonic muscle depth (UMD) adjusted to a constant age of 150 days. By year 9, responses in LWT, UFD and UMD in both sexes, as judged by the divergence between selection and control line performance, amounted to 4·88 kg, –1·1 mm and 2·8 mm respectively; these responses are between 7 and 15% of the overall means of the traits concerned. Although selection was originally on index scores based on phenotypic records, the retrospective analyses reported here used the mixed model applications of residual maximum likelihood to estimate parameters and best linear unbiased prediction to predict breeding values. The statistical model comprised fixed effects plus random effects accounting for direct additive, maternal additive and temporary environmental variation. Estimated genetic trends obtained by regressing estimated breeding values on year of birth were similar to annual responses estimated by comparing selection and control line means. Estimates of direct heritabilities were 0·054, 0·177, 0·286, 0·561 and 0·410 for birth weight (BWT), weaning weight (WWT), LWT, UFD and UMD respectively. Corresponding estimates of maternal heritabilities were 0·287, 0·205, 0·160, 0·083 and 0·164. Phenotypic correlations between all pairs of traits were positive and usually moderately high. There were low negative direct additive correlations between BWT and WWT, and between BWT and LWT, but higher positive maternal additive correlations between all other pairs of weight traits

Genetic relationship between longevity and objectively or subjectively assessed performance traits in sheep using linear censored models

Genetic parameters of longevity in crossbred mule ewes, and genetic relationships among longevity, growth, body composition, and subjectively assessed traits on mule lambs and ewes have been estimated using Bayesian linear censored models. Additionally, the genetic associations between longevity and culling reasons were examined. Data comprised 1,797 observations of mule ewes for longevity, culling reasons, growth, body composition, mouth scores, and type traits. Longevity was defined as the time (in years) from 2 yr of age (the age at first lambing of most ewes) to culling or death. Censored data (i.e., observations for which only the lower bound of the true longevity is known, such as when the animals are still alive) comprised 24% of all observations for longevity. Bivariate analyses were used to analyze the longevity of the ewe with each performance trait by fitting linear Bayesian models considering censored observations. Longevity was split into 3 different sub-traits: age at culling due to teeth/mouth conditions, age at culling due to udder conditions, and age at culling due to other culling reasons. These sub-traits and their aggregation into the overall trait of longevity were analyzed in a multiple-trait model. The heritability of longevity was moderate at 0.27, whereas heritabilities of the growth and body composition traits ranged from 0.11 for average of shoulder, loin, and gigot conformation to 0.36 for ewe BW at first premating. Mouth scores and type traits had heritabilities ranging from 0.13 for jaw position to 0.39 for fleece quality. All analyzed traits showed low genetic correlations with longevity, ranging from –0.20 for average conformation scores in live animals to 0.18 for tooth angle. Teeth/mouth conditions resulted in the greatest heritability (0.15) among the sub-traits based on the separate culling reasons. Genetic correlations between separate culling reasons were low to high (0.12 to 0.63 for teeth/mouth conditions with udder conditions and other culling reasons, respectively). Longevity may be preferred as a selection criterion because of (i) its moderate heritability compared with its component sub-traits based on specific culling reasons, and (ii) its moderate to high genetic correlation with these component sub-traits. The moderate heritability for longevity reflects the potential of this trait for genetic improvement, especially when longevity is based on clearly defined culling reasons

The role of model complexity in assessing water supply system resilience

Assessing water supply system resilience is becoming increasingly important as system pressures, including climate change and population, increase. The resilience of water supply systems in the UK to droughts of differing intensity and duration is now assessed through the simulation of a range of extreme droughts using water resource models. This process can be time consuming, data intensive and in some cases, may not be proportionate to the system response. The drought response surface has become a useful tool in UK water resources planning to quickly visualise modelled outputs, and therefore resilience, to droughts of differing intensity and duration. Work undertaken as part of the NERC Historic Droughts project has sought to compare results within the drought response surface framework to different levels of modelling complexity. Models of increasing complexity were developed that are rapid, accommodate varying data quality and provenance, and can be applied worldwide. Droughts were characterised for a range of reservoir systems based on duration and system response in the historic record. Flexible linear and polynomial regression models were trained on historic storage data and increasingly complex inputs – firstly rainfall, then site-translated historic reconstructed streamflow, and finally site-specific historic reconstructed streamflow – to hindcast reservoir storage to 1891. System understanding was important in drought duration selection, which was dependent on the length and distribution of reservoir storage in the observed record. The models permit the input of fuzzy data points, accommodating anecdotal evidence related to drought intensity and duration. Extreme value analysis of storage allowed for water company levels of service to be considered, therefore providing a description of the system response of an event in terms of the customer experience. Drought response surfaces produced under increasingly complex inputs were compared with those produced through water resource modelling to demonstrate the implications of different levels of modelling complexity. While simple, statistical modelling approaches that do not incorporate physical parameters should not replace deterministic system modelling, they allow for identification of periods and systems of interest that can focus further, more detailed analysis using more complex models and may have particular applications in data and model poor regions

Index Selection in Terminal Sires Improves Lamb Performance at Finishing

Lamb meat is often perceived by consumers as fatty, and consumption has decreased in recent decades. A lean growth index was developed in the UK for terminal sire breeds to increase carcass lean content and constrain fat content at a constant age end point. The purposes of this study were 1) to evaluate the effects of index selection of terminal sires on their crossbred offspring at finishing and 2) to evaluate its effectiveness within terminal sire breeds. Approximately 70% of lambs marketed in the UK have been sired by rams of breeds typically thought of as specialized terminal sires. The most widely used are Charollais, Suffolk, and Texel. These breeds participated in sire referencing schemes from the early 1990s by sharing rams among flocks selected on the lean growth index. From 1999 to 2002 approximately 15 “high” and 15 “low” lean growth index score rams were selected from within their sire referencing schemes and mated to Welsh and Scottish Mule ewes. Their crossbred offspring were commercially reared on 3 farms in the UK. Lambs were finished to an estimated 11% subcutaneous fat by visual evaluation. At finishing, lambs were weighed, ultrasonically scanned, and assessed for condition score and conformation. Records were obtained for 6,356 lambs on finishing BW (FWT), ultrasonic muscle depth (UMD), ultrasonic fat depth, overall condition score (OCS), and conformation of gigot, loin, and shoulder. Ultrasonic fat depth was log transformed (logUFD) to approach normality. High-index-sired lambs were heavier at finishing (1.2 ± 0.2 kg) with thicker UMD (0.7 ± 0.2 mm) and less logUFD (0.08 ± 0.01 mm; P \u3c 0.05). There were no differences in OCS or conformation based on the sire index or breed (P \u3e 0.08). Suffolk-sired lambs were heavier than Charollais (1.0 ± 0.3 kg), which were heavier than Texel (0.9 ± 0.3 kg; P \u3c 0.001). Texel-sired lambs had thicker UMD than Charollais (0.7 ± 0.2 mm; P \u3c 0.001) but were not different than Suffolk. Charollais-sired lambs had greater logUFD than both Texel (0.098 ± 0.016 mm) and Suffolk (0.061 ± 0.017 mm) sired lambs (P \u3c 0.001). Within a breed, high- and low-index-sired lambs differed in performance with the exceptions of FWT and UMD in Suffolks. Index selection produced heavier and leaner lambs at finishing. Producers have flexibility in choosing the terminal sire that best fits their production system