Acidification effects on biofouling communities: winners and losers

How ocean acidification affects marine life is a major concern for science and society. However, its impacts on encrusting biofouling communities, that are both the initial colonizers of hard substrata and of great economic importance, are almost unknown. We showed that community composition changed significantly, from 92% spirorbids, 3% ascidians and 4% sponges initially to 47% spirorbids, 23% ascidians and 29% sponges after 100days in acidified conditions (pH 7.7). In low pH, numbers of the spirorbid Neodexiospira pseudocorrugata were reduced x5 compared to controls. The two ascidians present behaved differently with Aplidium sp. decreasing x10 in pH 7.7, whereas Molgula sp. numbers were x4 higher in low pH than controls. Calcareous sponge (Leucosolenia sp.) numbers increased x2.5 in pH 7.7 over controls. The diatom and filamentous algal community was also more poorly developed in the low pH treatments compared to controls. Colonization of new surfaces likewise showed large decreases in spirorbid numbers, but numbers of sponges and Molgula sp. increased. Spirorbid losses appeared due to both recruitment failure and loss of existing tubes. Spirorbid tubes are comprised of a loose prismatic fabric of calcite crystals. Loss of tube materials appeared due to changes in the binding matrix and not crystal dissolution, as SEM analyses showed crystal surfaces were not pitted or dissolved in low pH conditions. Biofouling communities face dramatic future changes with reductions in groups with hard exposed exoskeletons and domination by soft-bodied ascidians and sponges.EU [227799, 00415/2010]; Natural Environment Research Council [bas0100036, bas0100025

Duration of ruptured membranes and mother-to-child HIV transmission: a prospective population-based surveillance study

OBJECTIVE: To investigate the association between duration of rupture of membranes (ROM) and mother-to-child HIV transmission (MTCT) rates in the era of combination antiretroviral therapy (cART). DESIGN: The National Study of HIV in Pregnancy and Childhood (NSHPC) undertakes comprehensive population-based surveillance of HIV in pregnant women and children. SETTING: UK and Ireland. POPULATION: A cohort of 2398 singleton pregnancies delivered vaginally, or by emergency caesarean section, in women on cART in pregnancy during the period 2007-2012 with information on duration of ROM; HIV infection status was available for 1898 infants. METHODS: Descriptive analysis of NSHPC data. MAIN OUTCOME MEASURES: Rates of MTCT. RESULTS: In 2116 pregnancies delivered at term, the median duration of ROM was 3 hours 30 minutes (interquartile range, IQR 1-8 hours). The overall MTCT rate for women delivering at term with duration of ROM ≥4 hours was 0.64% compared with 0.34% for ROM <4 hours, with no significant difference between the groups (OR 1.90, 95% CI 0.45-7.97). In women delivering at term with a viral load of <50 copies/ml, there was no evidence of a difference in MTCT rates with duration of ROM ≥4 hours, compared with <4 hours (0.14% for ≥4 hours versus 0.12% for <4 hour; OR 1.14, 95% CI 0.07-18.27). Among infants born preterm with infection status available, there were no transmissions in 163 deliveries where the maternal viral load was <50 copies/ml. CONCLUSIONS: No association was found between duration of ROM and MTCT in women taking cART. TWEETABLE ABSTRACT: Rupture of membranes of more than 4 hours is not associated with MTCT of HIV in women on effective ART delivering at term

CryoEM and stability analysis of virus-like particles of potyvirus and ipomovirus infecting a common host

Sweet potato feathery mottle virus (SPFMV) and Sweet potato mild mottle virus (SPMMV) are members of the genera Potyvirus and Ipomovirus, family Potyviridae, sharing Ipomoea batatas as common host, but transmitted, respectively, by aphids and whiteflies. Virions of family members consist of flexuous rods with multiple copies of a single coat protein (CP) surrounding the RNA genome. Here we report the generation of virus-like particles (VLPs) by transient expression of the CPs of SPFMV and SPMMV in the presence of a replicating RNA in Nicotiana benthamiana. Analysis of the purified VLPs by cryo-electron microscopy, gave structures with resolutions of 2.6 and 3.0 Å, respectively, showing a similar left-handed helical arrangement of 8.8 CP subunits per turn with the C-terminus at the inner surface and a binding pocket for the encapsidated ssRNA. Despite their similar architecture, thermal stability studies reveal that SPMMV VLPs are more stable than those of SPFMV

Reasoning from connectives and relations between entities

This article reports investigations of inferences that depend both on connectives between clauses, such as or else, and on relations between entities, such as in the same place as. Participants made more valid inferences from biconditionals—for instance, Ann is taller than Beth if and only if Beth is taller than Cath—than from exclusive disjunctions (Exp. 1). They made more valid transitive inferences from a biconditional when a categorical premise affirmed rather than denied one of its clauses, but they made more valid transitive inferences from an exclusive disjunction when a categorical premise denied rather than affirmed one of its clauses (Exp. 2). From exclusive disjunctions, such as Either Ann is not in the same place as Beth or else Beth is not in the same place as Cath, individuals tended to infer that all three individuals could be in different places, whereas in fact this was impossible (Exps. 3a and 3b). The theory of mental models predicts all of these results

Assessing the adequacy of self-reported alcohol abuse measurement across time and ethnicity: cross-cultural equivalence across Hispanics and Caucasians in 1992, non-equivalence in 2001–2002

<p>Abstract</p> <p>Background</p> <p>Do estimates of alcohol abuse reflect true levels across United States Hispanics and non-Hispanic Caucasians, or does culturally-based, systematic measurement error (i.e., measurement bias) affect estimates? Likewise, given that recent estimates suggest alcohol abuse has increased among US Hispanics, the field should also ask, "Does cross-ethnic change in alcohol abuse across time reflect true change or does measurement bias influence change estimates?"</p> <p>Methods</p> <p>To address these questions, I used confirmatory factor analyses for ordered-categorical measures to probe for measurement bias on two large, standardized, nationally representative, US surveys of alcohol abuse conducted in 1992 and 2001–2002. In 2001–2002, analyses investigated whether 10 items operationalizing DSM-IV alcohol abuse provided equivalent measurement across Hispanic (<it>n </it>= 4,893) and non-Hispanic Caucasians (<it>n </it>= 16,480). In 1992, analyses examined whether a reduced 6 item item-set provided equivalent measurement among 834 Hispanic and 14,8335 non-Hispanic Caucasians.</p> <p>Results</p> <p>In 1992, findings demonstrated statistically significant measurement bias for two items. However, sensitivity analyses showed that item-level bias did not appreciably bias item-set based alcohol abuse estimates among this cohort. For 2001–2002, results demonstrated statistically significant bias for seven items, suggesting caution regarding the cross-ethnic equivalence of alcohol abuse estimates among the current US Hispanic population. Sensitivity analyses indicated that item-level differences <it>did </it>erroneously impact alcohol abuse rates in 2001–2002, underestimating rates among Hispanics relative to Caucasians.</p> <p>Conclusion</p> <p>1992's item-level findings suggest that estimates of drinking related social or legal problems may underestimate these specific problems among Hispanics. However, impact analyses indicated no appreciable effect on alcohol abuse estimates resulting from the item-set. Efforts to monitor change in alcohol abuse diagnoses among the Hispanic community can use 1992 estimates as a valid baseline. In 2001–2002, item-level measurement bias on seven items did affect item-set based estimates. Bias underestimated Hispanics' self-reported alcohol abuse levels relative to non-Hispanic Caucasians. Given the cross-ethnic equivalence of 1992 estimates, bias in 2001–2002 speciously minimizes current increases in drinking behavior evidenced among Hispanics. Findings call for increased public health efforts among the Hispanic community and underscore the necessity for cultural sensitivity when generalizing measures developed in the majority to minorities.</p

A unified approach to molecular epidemiology investigations: tools and patterns in California as a case study for endemic shigellosis

<p>Abstract</p> <p>Background</p> <p>Shigellosis causes diarrheal disease in humans from both developed and developing countries, and multi-drug resistance is an emerging problem. The objective of this study is to present a unified approach that can be used to characterize endemic and outbreak patterns of shigellosis using use a suite of epidemiologic and molecular techniques. The approach is applied to a California case study example of endemic shigellosis at the population level.</p> <p>Methods</p> <p>Epidemiologic patterns were evaluated with respect to demographics, multi-drug resistance, antimicrobial resistance genes, plasmid profiles, and pulsed-field gel electrophoresis (PFGE) fingerprints for the 43 <it>Shigella </it>isolates obtained by the Monterey region health departments over the two year period from 2004-2005.</p> <p>Results</p> <p>The traditional epidemiologic as well as molecular epidemiologic findings were consistent with endemic as compared to outbreak shigellosis in this population. A steady low level of cases was observed throughout the study period and high diversity was observed among strains. In contrast to most studies in developed countries, the predominant species was <it>Shigella flexneri </it>(51%) followed closely by <it>S. sonnei </it>(49%). Over 95% of <it>Shigella </it>isolates were fully resistant to three or more antimicrobial drug subclasses, and 38% of isolates were resistant to five or more subclasses. More than half of <it>Shigella </it>strains tested carried the <it>tetB</it>, <it>catA</it>, or <it>bla</it>_TEMgenes for antimicrobial resistance to tetracycline, chloramphenicol, and ampicillin, respectively.</p> <p>Conclusion</p> <p>This study shows how epidemiologic patterns at the host and bacterial population levels can be used to investigate endemic as compared to outbreak patterns of shigellosis in a community. Information gathered as part of such investigations will be instrumental in identifying emerging antimicrobial resistance, for developing treatment guidelines appropriate for that community, and to provide baseline data with which to compare outbreak strains in the future.</p

Six sigma, absorptive capacity and organisational learning orientation

"This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Production Research, available online: http://wwww.tandfonline.com/10.1080/00207543.2010.543175."The importance of the Six Sigma methodology in industry is growing constantly. However, there are few empirical studies that analyze the advantages of this methodology and its positive effects on organizational performance. The purpose of this paper is to extend understanding of the success of Six Sigma quality management initiatives by investigating the effects of Six Sigma teamwork and process management on absorptive capacity. It also seeks to understand the relation between absorptive capacity and organizational learning as two sources of sustainable competitive advantage. The information used comes from a larger study, the data for which were collected from a random sample of 237 European firms. Of these 237 organizations, 58 are Six Sigma organizations. Structural Equation Modelling (SEM) was used to test the hypotheses. The main findings show that Six Sigma teamwork and process management positively affect the development of absorptive capacity. A positive and significant relationship is also observed between absorptive capacity and organizational learning orientation. The findings of this study justify Six Sigma implementation in firms. This study provides us with an in-depth understanding of some structural elements that characterize the Six Sigma methodology, enabling us to provide an explanation for its success

A Replicating Viral Vector Greatly Enhances Accumulation of Helical Virus-Like Particles in Plants

The production of plant helical virus-like particles (VLPs) via plant-based expression has been problematic with previous studies suggesting that an RNA scaffold may be necessary for their efficient production. To examine this, we compared the accumulation of VLPs from two potexviruses, papaya mosaic virus and alternanthera mosaic virus (AltMV), when the coat proteins were expressed from a replicating potato virus X- based vector (pEff) and a non-replicating vector (pEAQ-HT). Significantly greater quantities of VLPs could be purified when pEff was used. The pEff system was also very efficient at producing VLPs of helical viruses from different virus families. Examination of the RNA content of AltMV and tobacco mosaic virus VLPs produced from pEff revealed the presence of vector-derived RNA sequences, suggesting that the replicating RNA acts as a scaffold for VLP assembly. Cryo-EM analysis of the AltMV VLPs showed they had a structure very similar to that of authentic potexvirus particles. Thus, we conclude that vectors generating replicating forms of RNA, such as pEff, are very efficient for producing helical VLPs

Effect of controlled and uncontrolled cooling rate on motility parameters of cryopreserved ram spermatozoa

<p>Abstract</p> <p>Background</p> <p>Ram spermatozoa are sensitive to extreme changes in temperature during the freeze-thaw process. The degree of damage depends on a combined effect of various factors including freezing temperature. The aim of this study was to determine the effects of two cooling method (controlled-rate and uncontrolled-rate) on pre-freezing and post-thaw sperm motility parameters.</p> <p>Results</p> <p>Ejaculates were collected using the artificial vagina from four Chal rams and three replicates of the ejaculates were diluted with a Tris-based extender and packed in 0.25 ml straws. Then, sample processed according to the two methods. Method 1: straws cooled from 37 to 5°C, at a liner rate of -0.3°C/min in a controlled-rate cooling machine (custom-built) and equilibrated at 5°C for 80 min, then the straws were frozen at rate of -0.3°C/min from 5°C to -10°C and -25°C/min from -10°C to -150°C and plunged into liquid nitrogen for storage. Method 2: straws were transferred to refrigerator and maintained at 5°C for 3 h, then the straws were frozen in liquid nitrogen vapor, 4 cm above the liquid nitrogen for 15 min and plunged into liquid nitrogen. Computer-assisted sperm motility analysis was used to analyze sperm motion characteristics.</p> <p>Conclusions</p> <p>Controlled rate of freezing (Method 1) significantly improve the pre-freezing and post-thaw total and progressive motility compared to uncontrolled rate (Method 2). In specific kinetic parameters, Method 1 gives significantly higher value for VSL and VCL in comparison with Method 2. There are no significant differences between the two methods for VAP and LIN. In conclusion, controlled rate of cooling conferred better cryopreserving ability to ram spermatozoa compared to uncontrolled rate of cooling prior to programmable freezing.</p

Cross-National Measurement Invariance of the Teacher and Classmate Support Scale

The cross-national measurement invariance of the teacher and classmate support scale was assessed in a study of 23202 Grade 8 and 10 students from Austria, Canada, England, Lithuania, Norway, Poland, and Slovenia, participating in the Health Behaviour in School-aged Children (HBSC) 2001/2002 study. A multi-group means and covariance analysis supported configural and metric invariance across countries, but not full scalar equivalence. The composite reliability was adequate and highly consistent across countries. In all seven countries, teacher support showed stronger associations with school satisfaction than did classmate support, with the results being highly consistent across countries. The results indicate that the teacher and classmate support scale may be used in cross-cultural studies that focus on relationships between teacher and classmate support and other constructs. However, the lack of scalar equivalence indicates that direct comparison of the levels support across countries might not be warranted