Probabilistic models to describe the dynamics of migrating microbial communities

In all but the most sterile environments bacteria will reside in fluid being transported through conduits and some of these will attach and grow as biofilms on the conduit walls. The concentration and diversity of bacteria in the fluid at the point of delivery will be a mix of those when it entered the conduit and those that have become entrained into the flow due to seeding from biofilms. Examples include fluids through conduits such as drinking water pipe networks, endotracheal tubes, catheters and ventilation systems. Here we present two probabilistic models to describe changes in the composition of bulk fluid microbial communities as they are transported through a conduit whilst exposed to biofilm communities. The first (discrete) model simulates absolute numbers of individual cells, whereas the other (continuous) model simulates the relative abundance of taxa in the bulk fluid. The discrete model is founded on a birth-death process whereby the community changes one individual at a time and the numbers of cells in the system can vary. The continuous model is a stochastic differential equation derived from the discrete model and can also accommodate changes in the carrying capacity of the bulk fluid. These models provide a novel Lagrangian framework to investigate and predict the dynamics of migrating microbial communities. In this paper we compare the two models, discuss their merits, possible applications and present simulation results in the context of drinking water distribution systems. Our results provide novel insight into the effects of stochastic dynamics on the composition of non-stationary microbial communities that are exposed to biofilms and provides a new avenue for modelling microbial dynamics in systems where fluids are being transported

Characterization of substance use among underrepresented sexual and gender minority participants in The Population Research in Identity and Disparities for Equality (PRIDE) Study

Background: Profiles of substance use among less commonly described subgroups of sexual and gender minority (SGM) people (e.g., queer, genderqueer) remain largely unknown. Objective(s): To identify substance use differences among less commonly described SGM identity-based subgroups. Methods: The PRIDE Study is a national, online, longitudinal cohort study of self-identified SGM adults living in the U.S. Between 2015–2017, an iPhone application was used to administer three cross-sectional health questionnaires to participants, one of which included questions about binge alcohol, marijuana, and other drug use (substance use). This study was a secondary data analysis of participant responses to substance use survey items. Logistic regression and generalized linear modeling assessed relationships between sexual orientation or gender and use of or reported problems with substances within the past year. Results: Among the 1790 participants included in this study, 51.0% reported binge alcohol use, 39.8% reported marijuana use, and 19.7% reported other drug use (65.9% endorsed use of one or more of these) within the past year. Over 30% indicated substance use had been a problem in their life. Asexual individuals had lower odds of reporting past year binge alcohol and marijuana use (aOR: 0.27, 95% CI: 0.12–0.61; aOR: 0.38, 95% CI: 0.15–0.96, respectively), and queer participants had higher odds of reporting past year marijuana use (aOR: 2.52, 95% CI: 1.58–4.03) compared to lesbian participants. Gender nonbinary participants had lower odds of reporting past year binge alcohol use (aOR: 0.48, 95% CI: 0.32–0.71) and transmasculine participants had higher odds of reporting past year marijuana use (aOR: 2.18, 95% CI: 1.10–4.31) compared to cisgender women. Conclusions: Substance use heterogeneity exists between SGM groups. Comprehensive assessment of sexual orientation and gender may improve understanding of substance use and increase equity within support and treatment services for SGM populations.Highlights We examined substance use among less represented sexual and gender minority groups. Alcohol and other drug use were examined by both sexual orientation and gender identity. Analyses included identities such as queer, pansexual, genderqueer and nonbinary. Alcohol use differed across asexual, genderqueer and gender nonbinary groups. Marijuana use differed across queer, asexual and transmasculine groups

Dislocation Nucleation and Propagation in Semiconductor Heterostructures

This paper considers misfit dislocation nucleation and propagation in dilute magnetic semiconductor heterostructures in the CdTe-ZnTe-MnTe system. It is shown that, where the deposit is in tension, 1/2 \u3c 110 \u3e dislocations with inclined Burgers vectors propagate by glide along interfacial \u3c 110 \u3e directions and may dissociate giving intrinsic stacking faults. In cases where the deposit is in compression, 1/2 \u3c 110 \u3e dislocations show no evidence of dissociation and propagate by extensive cross-slip to give networks of dislocations close to interfacial \u3c 100 \u3e directions. Evidence for dislocation sources in ZnTe/GaSb films is presented. ZnTe films contained stacking fault pyramids, single Frank faults and a new type of diamond defect are present at densities up to about 107 cm-2. Analysis showed that the diamond defects, which were four-sided defects on {111} planes with \u3c 110 \u3e edges, were of vacancy type with 1/3 \u3c 111 \u3e Frank Burgers vectors and intrinsic stacking faults. Although faulted defects showed no tendency to grow by climb, evidence is given for an unfaulted reaction in which a glissile 1/2 \u3c 110 \u3e dislocation is generated. This new model for dislocation nucleation is discussed

Against the Standards: Analyzing Expectations and Discourse of Educators regarding Students with Disabilities in a Kindergarten Classroom

This two-year ethnographic case study critically examines the language educators use to describe students with disabilities who are considered to present challenging behaviors in one classroom. Focusing on the language and practices used by one special education teacher and three teaching assistants, this paper explores how educators respond to students' behaviors by analyzing educators' utterances and the implication of such use for the education of the students. Using critical discourse analysis, this paper highlights how educators' language in the classroom reflects a discourse of expectations that is based on various social standards and pressures that educators have to juggle. Educators expressed academic and behavioral standards by comparing students' performance to the expected norm as well as through comparisons between students. Based on such comparisons, some students were constructed as always lacking and ultimately defined by the adjectives originally used to describe them. Students were perceived to embody defiance or smartness, the characteristics by which they were defined

HIV-infected sex workers with beneficial HLA-variants are potential hubs for selection of HIV-1 recombinants that may affect disease progression

Cytotoxic T lymphocyte (CTL) responses against the HIV Gag protein are associated with lowering viremia; however, immune control is undermined by viral escape mutations. The rapid viral mutation rate is a key factor, but recombination may also contribute. We hypothesized that CTL responses drive the outgrowth of unique intra-patient HIV-recombinants (URFs) and examined gag sequences from a Kenyan sex worker cohort. We determined whether patients with HLA variants associated with effective CTL responses (beneficial HLA variants) were more likely to carry URFs and, if so, examined whether they progressed more rapidly than patients with beneficial HLA-variants who did not carry URFs. Women with beneficial HLA-variants (12/52) were more likely to carry URFs than those without beneficial HLA variants (3/61) (p < 0.0055; odds ratio = 5.7). Beneficial HLA variants were primarily found in slow/standard progressors in the URF group, whereas they predominated in long-term non-progressors/survivors in the remaining cohort (p = 0.0377). The URFs may sometimes spread and become circulating recombinant forms (CRFs) of HIV and local CRF fragments were over-represented in the URF sequences (p < 0.0001). Collectively, our results suggest that CTL-responses associated with beneficial HLA variants likely drive the outgrowth of URFs that might reduce the positive effect of these CTL responses on disease progression

Distributed expertise: Qualitative study of a British network of multidisciplinary teams supporting parents of children with chronic kidney disease

© 2014 The Authors. Background: Long-term childhood conditions are often managed by hospital-based multidisciplinary teams (MDTs) of professionals with discipline specific expertise of a condition, in partnership with parents. However, little evidence exists on professional-parent interactions in this context. An exploration of professionals' accounts of the way they individually and collectively teach parents to manage their child's clinical care at home is, therefore, important for meeting parents' needs, informing policy and educating novice professionals. Using chronic kidney disease as an exemplar this paper reports on one aspect of a study of interactions between professionals and parents in a network of 12 children's kidney units in Britain. Methods: We conducted semi-structured, qualitative interviews with a convenience sample of 112 professionals (clinical-psychologists, dietitians, doctors, nurses, pharmacists, play-workers, therapists and social workers), exploring accounts of their parent-educative activity. We analysed data using framework and the concept of distributed expertise. Results: Four themes emerged that related to the way expertise was distributed within and across teams: (i) recognizing each other's' expertise, (ii) sharing expertise within the MDT, (iii) language interpretation, and (iv) acting as brokers. Two different professional identifications were also seen to co-exist within MDTs, with participants using the term 'we' both as the intra-professional 'we' (relating to the professional identity) when describing expertise within a disciplinary group (for example: 'As dietitians we aim to give tailored advice to optimize children's growth'), and the inter-professional 'we' (a 'team-identification'), when discussing expertise within the team (for example: 'We work as a team and make sure we're all happy with every aspect of their training before they go home'). Conclusions: This study highlights the dual identifications implicit in 'being professional' in this context (to the team and to one's profession) as well as the unique role that each member of a team contributes to children's care. Our methodology and results have the potential to be transferred to teams managing other conditions

RELATIONSHIP BETWEEN HORMONAL BALANCE AND GROWTH IN MALNOURISHED CHILDREN AND RATS

1. Plasma concentrations of insulin, cortisol and growth hormone, and growth velocities have been measured in a group of Gambian village children up to 3 years of age. All three hormones showed changes in concentration with age, as did rates of growth. 2. Plasma insulin concentrations in the children were directly correlated with velocity of growth in height and weight, whereas cortisol concentrations showed inverse relationships. The values for insulin:cortisol concentration correlated more closely with growth velocity than did either hormone individually. Growth hormone values in plasma exhibited only marginal correlations with growth in height or weight, and these were negative. 3. Similar relationships between these hormones and growth were obtained from an animal experiment in which the rates of growth of rats were altered by restricting dietary intake of protein or energy or both. 4. Possible mechanisms for these observations are discussed in the light of recent knowledge concerning the hormonal control of growth rates

Screening gender minority people for harmful alcohol use

This study identifies how to screen for harmful alcohol use among gender minority (e.g., transgender and gender-expansive) people using brief screening methods and identifies which screening methods perform best among gender-expansive, transfeminine, and transmasculine subgroups, as screening recommendations are not currently available. Using 2018 Annual Questionnaire data from The PRIDE Study, area under the curve (AUC) values were compared to identify which screening methods (“4 or more” or “5 or more” drinks on one occasion in the past year, or one or more items from the Alcohol Use Disorders Identification Test [AUDIT]) best predicted (i) harmful alcohol use and (ii) one or more past year alcohol dependence symptoms or consequences. Among 1892 participants, “5 or more” drinks on one occasion (AUC ranges: 0.82-0.86) performed better than “4 or more” drinks (AUC ranges: 0.78-0.81) in predicting harmful drinking. The screening methods “4 or more” drinks, “5 or more” drinks, and the consumption items of the AUDIT (AUDIT-C) using a cutoff score of 3 all maximized sensitivity and specificity to predict alcohol dependence symptoms or consequences in gender minority people overall (AUC: 0.77-0.78). Screening for “5 or more” drinks on one occasion within the past year performed as well as or better than other screening methods to detect both harmful drinking and alcohol dependence-related symptoms or consequences. This single-item screening method can identify if more extensive alcohol use assessment is warranted with gender minority people

Functional near infrared spectroscopy (fNIRS) to assess cognitive function in infants in rural Africa

Cortical mapping of cognitive function during infancy is poorly understood in low-income countries due to the lack of transportable neuroimaging methods. We have successfully piloted functional near infrared spectroscopy (fNIRS) as a neuroimaging tool in rural Gambia. Four-to-eight month old infants watched videos of Gambian adults perform social movements, while haemodynamic responses were recorded using fNIRS. We found distinct regions of the posterior superior temporal and inferior frontal cortex that evidenced either visual-social activation or vocally selective activation (vocal > non-vocal). The patterns of selective cortical activation in Gambian infants replicated those observed within similar aged infants in the UK. These are the first reported data on the measurement of localized functional brain activity in young infants in Africa and demonstrate the potential that fNIRS offers for field-based neuroimaging research of cognitive function in resource-poor rural communities