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Detecting gastrointestinal (GI) infection transmission among men who have sex with men (MSM) in England is complicated by a lack of routine sexual behavioural data. We investigated whether gender distributions might generate signals for increased transmission of GI pathogens among MSM. We examined the percentage male of laboratory-confirmed patient-episodes for patients with no known travel history for 10 GI infections of public health interest in England between 2003 and 2013, stratified by age and region. An adult male excess was observed for Shigella spp. (annual maximum 71% male); most pronounced for those aged 25–49 years and living in London, Brighton and Manchester. An adult male excess was observed every year for Entamoeba histolytica (range 59.8–76.1% male), Giardia (53.1–57.6%) and Campylobacter (52.1–53.5%) and for a minority of years for hepatitis A (max. 69.8%) and typhoidal salmonella (max. 65.7%). This approach generated a signal for excess male episodes for six GI pathogens, including a characterised outbreak of Shigella among MSM. Stratified analyses by geography and age group were consistent with MSM transmission for Shigella. Optimisation and routine application of this technique by public health authorities elsewhere might help identify potential GI infection outbreaks due to sexual transmission among MSM, for further investigation.
Dense suspensions of hard particles are important as industrial or environmental materials (e.g. fresh concrete, food, paint or mud). To date, most constitutive models developed to describe them are, explicitly or effectively, ‘fabric evolution models’ based on: (i) a stress rule connecting the macroscopic stress to a second-rank microstructural fabric tensor
; and (ii) a closed time-evolution equation for
. In dense suspensions, most of the stress comes from short-ranged pairwise steric or lubrication interactions at near-contacts (suitably defined), so a natural choice for
is the deviatoric second moment of the distribution
of the near-contact orientations
. Here we test directly whether a closed time-evolution equation for such a
can exist, for the case of inertialess non-Brownian hard spheres in a Newtonian solvent. We perform extensive numerical simulations accessing high levels of detail for the evolution of
under shear reversal, providing a stringent test for fabric evolution models. We consider a generic class of these models as defined by Hand (J. Fluid Mech., vol. 13, 1962, pp. 33–46) that assumes little as to the micromechanical behaviour of the suspension and is only constrained by frame indifference. Motivated by the smallness of microstructural anisotropies in the dense regime, we start with linear models in this class and successively consider those increasingly nonlinear in
. Based on these results, we suggest that no closed fabric evolution model properly describes the dynamics of the fabric tensor under reversal. We attribute this to the fact that, while a second-rank tensor captures reasonably well the microstructure in steady flows, it gives a poor description during significant parts of the microstructural evolution following shear reversal. Specifically, the truncation of
at second spherical harmonic (or second-rank tensor) level describes ellipsoidal distributions of near-contact orientations, whereas on reversal we observe distributions that are markedly four-lobed; moreover,
has oblique axes, not collinear with those of
in the shear plane. This structure probably precludes any adequate closure at second-rank level. Instead, our numerical data suggest that closures involving the coupled evolution of both a fabric tensor and a fourth-rank tensor might be reasonably accurate.
In England, dual tests detecting chlamydia and gonorrhoea are used in specialist and community-based sexual health services (SHSs). Test performance is poor when prevalence is low, therefore UK national guidelines recommend against opportunistic gonorrhoea screening unless there is a clear local public health need. While surveillance data on gonorrhoea prevalence is comprehensive in specialist SHSs, it is sparse in community SHSs. We aimed to estimate gonorrhoea prevalence in heterosexual men and women aged 15–24 attending community SHSs to inform testing care pathways. We used linear and quadratic regression to model the relationship between prevalence in community and specialist SHSs in local authorities (LAs) with available surveillance data. We applied best-fitting models to predict prevalence in community SHSs in remaining LAs. Data from community SHSs were available for 102/326 LAs. There was a weak positive association between gonorrhoea prevalence in community and specialist SHSs in corresponding LAs within (R2 = 0·13, P = 0·058) and outside (R2 = 0·07, P = 0·02) London. Applying best-fitting models, we estimated a median gonorrhoea prevalence of 0·5% (mean 0·6%; range 0·2%–2·7%) in heterosexuals attending community SHSs. Despite some unexplained variation, our analyses suggest gonorrhoea prevalence in young heterosexuals attending community SHSs is below 1% in most English LAs. Our findings re-inforce the current national guidelines that recommend care pathways for gonorrhoea testing in community SHSs include confirmatory testing to reduce the risk of misdiagnosis and inappropriate management.
Shifting prey distributions due to global warming are expected to generate dramatic ecosystem-wide changes in trophic structure within Arctic marine ecosystems. Yet a relatively poor understanding of contemporary Arctic food webs makes it difficult to predict the consequences of such changes for Arctic predators. Doing so requires quantitative approaches that can track contemporary changes in predator diets through time, using accurate, well-defined methods. Here we use fatty acids (FA) to quantify differences in consumer diet using permutational multivariate analysis of variance tests that characterize spatial and temporal changes in consumer FA signatures. Specifically we explore differences in Greenland shark (Somniosus microcephalus) FA to differentiate their potential trophic role between Svalbard, Norway and Cumberland Sound, Canada. Greenland shark FA signatures revealed significant inter-annual differences, probably driven by varying seal and Greenland halibut responses to environmental conditions such as the NAO, bottom temperature, and annual sea-ice extent. Uncommon FA were also found to play an important role in driving spatial and temporal differences in Greenland shark FA profiles. Our statistical approach should facilitate quantification of changing consumer diets across a range of marine ecosystems.
The nutrient choline is necessary for membrane synthesis and methyl donation, with increased requirements during lactation. The majority of immune development occurs postnatally, but the importance of choline supply for immune development during this critical period is unknown. The objective of this study was to determine the importance of maternal supply of choline during suckling on immune function in their offspring among rodents. At parturition, Sprague–Dawley dams were randomised to either a choline-devoid (ChD; n 7) or choline-sufficient (ChS, 1 g/kg choline; n 10) diet with their offspring euthanised at 3 weeks of age. In a second experiment, offspring were weaned to a ChS diet until 10 weeks of age (ChD-ChS, n 5 and ChS-ChS, n 9). Splenocytes were isolated, and parameters of immune function were measured. The ChD offspring received less choline in breast milk and had lower final body and organ weight compared with ChS offspring (P<0·05), but this effect disappeared by week 10 with choline supplementation from weaning. ChD offspring had a higher proportion of T cells expressing activation markers (CD71 or CD28) and a lower proportion of total B cells (CD45RA+) and responded less to T cell stimulation (lower stimulation index and less IFN-γ production) ex vivo (P<0·05). ChD-ChS offspring had a lower proportion of total and activated CD4+ T cells, and produced less IL-6 after mitogen stimulation compared with cells from ChS-ChS (P<0·05). Our study suggests that choline is required in the suckling diet to facilitate immune development, and choline deprivation during this critical period has lasting effects on T cell function later in life.
Previous research in leeward Kohala, Hawai'i Island, has determined that the Leeward Kohala Field System (LKFS), a vast agricultural zone covering ∼60 km2, developed between the 14th and 18th centuries AD. Additional analyses have documented the establishment of traditional socioeconomic territories, known as ahupua'a, in tandem with the expansion of the field system. This article further refines the chronology of human settlement and socioeconomic development in leeward Kohala through the analysis of deposits associated with prehistoric residences. Based upon survey and excavation, we present a chronology for Hawaiian household transition and economic development in 2 study areas of leeward Kohala, spanning the field system to the coast. Forty-nine radiocarbon dates from short-lived plant materials and 5 230Th dates on corals from residential and ritual features are synthesized into 3 temporal periods, which allow for comparison of residential size, distribution, number, and associated faunal materials from archaeological deposits. Changes in household composition and economy are suggested to have developed in tandem with the establishment of individual ahupua'a and land divisions within them, and the further development of agricultural production.
Data were pooled from three Australian sentinel general practice influenza surveillance networks to estimate Australia-wide influenza vaccine coverage and effectiveness against community presentations for laboratory-confirmed influenza for the 2012, 2013 and 2014 seasons. Patients presenting with influenza-like illness at participating GP practices were swabbed and tested for influenza. The vaccination odds of patients testing positive were compared with patients testing negative to estimate influenza vaccine effectiveness (VE) by logistic regression, adjusting for age group, week of presentation and network. Pooling of data across Australia increased the sample size for estimation from a minimum of 684 to 3,683 in 2012, from 314 to 2,042 in 2013 and from 497 to 3,074 in 2014. Overall VE was 38% [95% confidence interval (CI) 24–49] in 2012, 60% (95% CI 45–70) in 2013 and 44% (95% CI 31–55) in 2014. For A(H1N1)pdm09 VE was 54% (95% CI–28 to 83) in 2012, 59% (95% CI 33–74) in 2013 and 55% (95% CI 39–67) in 2014. For A(H3N2), VE was 30% (95% CI 14–44) in 2012, 67% (95% CI 39–82) in 2013 and 26% (95% CI 1–45) in 2014. For influenza B, VE was stable across years at 56% (95% CI 37–70) in 2012, 57% (95% CI 30–73) in 2013 and 54% (95% CI 21–73) in 2014. Overall VE against influenza was low in 2012 and 2014 when A(H3N2) was the dominant strain and the vaccine was poorly matched. In contrast, overall VE was higher in 2013 when A(H1N1)pdm09 dominated and the vaccine was a better match. Pooling data can increase the sample available and enable more precise subtype- and age group-specific estimates, but limitations remain.
Eating disorder behaviours begin in adolescence. Few longitudinal studies
have investigated childhood risk and protective factors.
To investigate the prevalence of eating disorder behaviours and
cognitions and associated childhood psychological, physical and parental
risk factors among a cohort of 14-year-old children.
Data were collected from 6140 boys and girls aged 14 years.
Gender-stratified models were used to estimate prospective associations
between childhood body dissatisfaction, body mass index (BMI),
self-esteem, maternal eating disorder and family economic disadvantage on
adolescent eating disorder behaviours and cognitions.
Childhood body dissatisfaction strongly predicted eating disorder
cognitions in girls, but only in interaction with BMI in boys. Higher
self-esteem had a protective effect, particularly in boys. Maternal
eating disorder predicted body dissatisfaction and weight/shape concern
in adolescent girls and dieting in boys.
Risk factors for eating disorder behaviours and cognitions vary according
to gender. Prevention strategies should be gender-specific and target
modifiable predictors in childhood and early adolescence.
The results of a new approach to the problem of the collisional step in the pumping cycle for OH and CH masers are reported. Rotationally inelastic collisions of OH and CH with both open and closed shell collision partners are considered using an expression derived from scattering theory. It is shown how Λ-doublet population inversion may arise in OH and CH. H-atoms and H2 may show opposite behaviour with CH, one partner cooling where collisions with the other lead to inversion. Implications for maser action are discussed and reveal excellent qualitative agreement with observation. Λ-doublet population inversion in OD, CD and NH+ is also considered.
On the evidence of some recent laboratory data for the association reaction H + OH + He → H2O + He, and following previously proposed ion-neutral association reaction schemes, we tentatively suggest that the radiative association reaction of H and OH can be a significant mechanism for the production of H2O in interstellar clouds, when compared with the ion-neutral reaction sequence. The ‘H-atom + radical’ association process may be of some general importance in the production of other small molecules in interstellar clouds.
Identifying childhood predictors of binge eating and understanding risk mechanisms could help improve prevention and detection efforts. The aim of this study was to examine whether features of attention-deficit/hyperactivity disorder (ADHD), as well as childhood eating disturbances, predicted binge eating later in adolescence.
We studied specific risk factors for the development of binge eating during mid-adolescence among 7120 males and females from the Avon Longitudinal Study of Parents and Children (ALSPAC), a cohort study of children in the UK, using data from multiple informants to develop structural equation models. Repeated assessment of eating disturbances during childhood (mid-childhood overeating, late-childhood overeating and early-adolescent strong desire for food), as well as teacher- and parent-reported hyperactivity/inattention during mid- and late childhood, were considered as possible predictors of mid-adolescent binge eating.
Prevalence of binge eating during mid-adolescence in our sample was 11.6%. The final model of predictors of binge eating during mid-adolescence included direct effects of late-childhood overeating [standardized estimate 0.145, 95% confidence interval (CI) 0.038–0.259, p = 0.009] and early-adolescent strong desire for food (standardized estimate 0.088, 95% CI −0.002 to 0.169, p = 0.05). Hyperactivity/inattention during late childhood indirectly predicted binge eating during mid-adolescence (standardized estimate 0.085, 95% CI 0.007–0.128, p = 0.03) via late-childhood overeating and early-adolescent strong desire for food.
Our findings indicate that early ADHD symptoms, in addition to an overeating phenotype, contribute to risk for adolescent binge eating. These findings lend support to the potential role of hyperactivity/inattention in the development of overeating and binge eating.
The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0–∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.
We investigated a mixed outbreak of Legionnaires' disease (LD) and Pontiac fever (PF) at a military base to identify the outbreak's environmental source as well as known legionellosis risk factors. Base workers with possible legionellosis were interviewed and, if consenting, underwent testing for legionellosis. A retrospective cohort study collected information on occupants of the buildings closest to the outbreak source. We identified 29 confirmed and probable LD and 38 PF cases. All cases were exposed to airborne pathogens from a cooling tower. Occupants of the building closest to the cooling tower were 6·9 [95% confidence interval (CI) 2·2–22·0] and 5·5 (95% CI 2·1–14·5) times more likely to develop LD and PF, respectively, than occupants of the next closest building. Thorough preventive measures and aggressive responses to outbreaks, including searching for PF cases in mixed legionellosis outbreaks, are essential for legionellosis control.
This Summary for Policymakers presents key findings from the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX). The SREX approaches the topic by assessing the scientific literature on issues that range from the relationship between climate change and extreme weather and climate events (‘climate extremes’) to the implications of these events for society and sustainable development. The assessment concerns the interaction of climatic, environmental, and human factors that can lead to impacts and disasters, options for managing the risks posed by impacts and disasters, and the important role that non-climatic factors play in determining impacts. Box SPM.1 defines concepts central to the SREX.
The character and severity of impacts from climate extremes depend not only on the extremes themselves but also on exposure and vulnerability. In this report, adverse impacts are considered disasters when they produce widespread damage and cause severe alterations in the normal functioning of communities or societies. Climate extremes, exposure, and vulnerability are influenced by a wide range of factors, including anthropogenic climate change, natural climate variability, and socioeconomic development (Figure SPM.1). Disaster risk management and adaptation to climate change focus on reducing exposure and vulnerability and increasing resilience to the potential adverse impacts of climate extremes, even though risks cannot fully be eliminated (Figure SPM.2). Although mitigation of climate change is not the focus of this report, adaptation and mitigation can complement each other and together can significantly reduce the risks of climate change. [SYR AR4, 5.3]
Chemical genetics (see this book and ) for an extensive review) offers a complementary approach to loss-of-function mutations in the analysis of complex, multicomponent biological processes. Large-scale mutagenesis screens using genetic model systems have been used very successfully for many years in identifying genes involved in developmental and physiological events. However, such screens are expensive and time consuming. In addition, with respect to later development and organogenesis, these screens can be limited in scope. During embryonic development, many patterning and signaling systems are used multiple times [2–4]. Thus, if an embryo is disrupted at an early time point because of a mutation, later events using the same pathway become difficult to study. Such mutagenesis screens therefore do not allow for the finer temporal control of protein function. The ability to have temporal control over compound addition and thus the modulation of protein function provides a more focused approach to phenotypic assays. This also means that chemical genomic screens are applicable to maternal proteins, which many traditional mutagenesis screens are not, significantly extending the opportunity to identify key endogenous players in biological processes.
In this chapter, we focus on some of the multicellular organisms commonly used for chemical genomic screens, including plants, worm (Caenorhabditis elegans), fruit fly (Drosophila melanogaster), fish (zebrafish), and frog (Xenopus). Table 10.1 shows some of the general advantages and disadvantages of commonly used model organisms. With respect to chemical genetics, which requires high-throughput screening (HTS), organisms producing large numbers of embryos are essential, so chick and mouse are not suitable for such screens. However, because of the conservation of protein sequence and especially protein structure between species, small molecules identified in screens in one species can be tested in another species, with the reasonable expectation that the compound will interact with a similar protein. Thus, molecules identified in screens can be tested in higher organisms such as mouse and chick as well as in other systems such as cell-based assays using human cells. In the case of plants, compounds identified in Arabidopsis spp. can then be tested in other species such as crops. Another advantage is that, in many cases, compounds that are toxic will have been screened out before testing in higher organisms.
Travel is a risk factor for Legionnaires' disease. In 2008, two cases were reported in condominium guests where we investigated a 2001 outbreak. We reinvestigated to identify additional cases and determine whether ongoing transmission resulted from persistent colonization of potable water. Exposures were assessed by matched case-control analyses (2001) and case-series interviews (2008). We sampled potable water and other water sources. Isolates were compared using sequence-based typing. From 2001 to 2008, 35 cases were identified. Confirmed cases reported after the cluster in 2001–2002 were initially considered sporadic, but retrospective case-finding identified five additional cases. Cases were more likely than controls to stay in tower 2 of the condominium [matched odds ratio (mOR) 6·1, 95% confidence interval (CI) 1·6–22·9]; transmission was associated with showering duration (mOR 23·0, 95% CI 1·4–384). We characterized a clinical isolate as sequence type 35 (ST35) and detected ST35 in samples of tower 2's potable water in 2001, 2002, and 2008. This prolonged outbreak illustrates the importance of striving for permanent Legionella eradication from potable water.
The H.M.S. Challenger and D/V Glomar Challenger; it gives those of us who have had the pleasure and good fortune to be associated with the Glomar Challenger and the Deep Sea Drilling Project the greatest of pride to be identified in the name of what was undoubtedly the most progressive of all deep-sea explorations, the voyage of the H.M.S. Challenger one hundred years ago.
As its sequel, we are deeply indebted to those who explored the deep ocean basins in the Challenger before, and whose courageous and inspired explorations were instrumental in making our Glomar Challenger possible.