A noncommutative framework for topological insulators

We study topological insulators, regarded as physical systems giving rise to topological invariants determined by symmetries both linear and anti-linear. Our perspective is that of noncommutative index theory of operator algebras. In particular we formulate the index problems using Kasparov theory, both complex and real. We show that the periodic table of topological insulators and superconductors can be realised as a real or complex index pairing of a Kasparov module capturing internal symmetries of the Hamiltonian with a spectral triple encoding the geometry of the sample's (possibly noncommutative) Brillouin zone.Comment: 32 pages, final versio

Wasted opportunities: Problematic alcohol and drug use among gay men and bisexual men

This report describes the findings from a qualitative and quantitative study of alcohol and drug use among gay and bisexual men and other men that have sex with men (MSM) in England. The qualitative element describes the experiences and understandings of men who identified themselves as being concerned about their alcohol or drug use. The quantitative element shows the broader picture of use and concern about use among MSM. So we go from a broad picture of the extent of alcohol and drug use and concern about it, to a narrower and more detailed focus on men experiencing concern and problems related to alcohol and drug use. The aims of the study are to qualitatively explore the contexts and attendant needs of men who are concerned about their substance use, to locate that use within the broader MSM population and to suggest ways in which the drug-related needs of MSM might be better met. So we have specifically recruited men who were concerned about their substance use and investigated the way these men used drugs and alcohol, what drugs and alcohol mean to them and the harms caused by drugs and alcohol. Many men, perhaps the majority, use alcohol and other drugs without any mishap or unhappiness. However, the range of experiences described highlight the pervasive and often detrimental role that alcohol and other drugs play in the social and personal lives of many men. Although there is some research which examines the effects of substance use treatments on sexual risk behaviour (that is, do drugs services reduce unsafe sex), there is little or no research which investigates the accessibility, acceptability or effectiveness of current substance use services for gay men and other MSM. So in the qualitative interviews we also sought information about the role services played in meeting drug-related needs, for example information, motivational and practical support

Low levels of chemsex among men who have sex with men, but high levels of risk among men who engage in chemsex: analysis of a cross-sectional online survey across four countries

Background: This paper establishes the prevalence of chemsex drug use among men who have sex with men (MSM), the extent to which these drugs are used in a sexual context, as well as their associated behaviours and circumstances of use. Methods: Data from a cross-sectional, online survey of 2328 MSM recruited via gay sociosexual media in Scotland, Wales, Northern Ireland and the Republic of Ireland were analysed. Results: While almost half (48.8%) of participants had ever taken illicit drugs, lifetime chemsex drug use was less common (18.0%) and far fewer reported chemsex drug use in the last year (8.2%) or last 4 weeks (3.0%). Just over one-quarter (27.1%) of men who used chemsex drugs in the last year reported no sexualised drug use, but almost three-quarters (72.9%) did. Only 6.1% of the whole sample reported sexualised chemsex drug use in the last year. The odds of reporting chemsex in the last year were significantly higher for men aged 36–45 years (AOR = 1.96), single men (AOR = 1.83), men who were HIV positive (AOR = 4.01), men who report high-risk sex (AOR = 4.46), being fisted (AOR = 7.77) or had sex in exchange for goods other than money (AOR = 4.7) in the last year and men who reported an HIV test in the last 3 months (AOR = 1.53). Discussion: Only a small proportion of MSM in Scotland, Wales, Northern Ireland and the Republic of Ireland reported chemsex, and, for the first time, it is demonstrated that not all chemsex drug use was sexualised. Nevertheless, MSM who engage in chemsex (MWEC) reported substantial sexual risk inequalities. These novel findings highlight several opportunities for intervention, particularly around the multiple vulnerabilities of MWEC, opportunities for early identification of those most vulnerable to chemsex-related harm and the potential to develop a specialised responsive patient pathway

Relative Safety 2: Risk and unprotected anal intercourse among gay men diagnosed with HIV

In 1999 Sigma Research published Relative safety: an investigation of risk and unprotected anal intercourse among gay men diagnosed with HIV (Keogh et al. 1999). This study explored the social, psychological and cultural meanings associated with unprotected anal intercourse (UAI) among men with diagnosed HIV. It highlighted both the complexity of sexual interaction for men with diagnosed HIV, and the many potential costs and benefits perceived by them. Now, with more than 24,000 homosexually active men diagnosed with HIV in the UK (Health Protection Agency 2008), a figure that is set to increase in years to come, it is vital that agencies involved in HIV prevention interrogate their own beliefs about UAI and ensure that their interventions meet the needs of men with diagnosed HIV. . . . . The following chapter explains how the study was undertaken, outlines the broad topic areas addressed during the interviews, and describes the sample of men who took part. Chapter 3 outlines the range of harms that men with HIV perceive when engaging in UAI. Chapters 4 and 5 explore the ways in which men responded to these perceived harms, firstly those relating to the risk of onward HIV infection, or superinfection, and latterly those concerning the potential for harms to their personal and social identities. Chapter 6 considers the implications of these findings for health promotion interventions targeting men with HIV, and with homosexually active men more broadly

What qualities in a potential HIV pre-exposure prophylaxis service are valued by black men who have sex with men in London? A qualitative acceptability study.

Black men who have sex with men (BMSM) have higher HIV incidence and prevalence when compared to other MSM, despite similar levels of condom use and testing. Pre-exposure prophylaxis (PrEP) could be a useful intervention to reduce these inequalities. This research therefore aims to understand the dimensions of acceptability of a potential PrEP service for BMSM aged 18-45 years in London. In-depth semi-structured interviews were conducted with 25 PrEP-eligible BMSM between April and August 2016. Interviews were recorded and transcribed verbatim, then subject to a thematic framework analysis, informed by intersectionality theory. BMSM had distinct preferences for sexual health services, which have implications for PrEP service development. Three primary domains emerged in our analysis: proximity and anonymity; quality, efficiency and reassurance; and understanding, empathy and identity. These relate, respectively, to preferences regarding clinic location and divisions from community, features of service delivery and staff characteristics. Due to concerns about confidentiality, community-based services may not be useful for this group. Careful consideration in regards to components used in service development will facilitate ongoing engagement. Interpersonal skills of staff are central to service acceptability, particularly when staff are perceived to be from similar cultural backgrounds as their patients

The KO-valued spectral flow for skew-adjoint Fredholm operators

In this article we give a comprehensive treatment of a `Clifford module flow' along paths in the skew-adjoint Fredholm operators on a real Hilbert space that takes values in KO${}_{*}(\mathbb{R})$ via the Clifford index of Atiyah-Bott-Shapiro. We develop its properties for both bounded and unbounded skew-adjoint operators including an axiomatic characterization. Our constructions and approach are motivated by the principle that $$\text{spectral flow} = \text{Fredholm index}.$$ That is, we show how the KO--valued spectral flow relates to a KO-valued index by proving a Robbin-Salamon type result. The Kasparov product is also used to establish a spectral flow $=$ Fredholm index result at the level of bivariant K-theory. We explain how our results incorporate previous applications of $\mathbb{Z}/ 2\mathbb{Z}$-valued spectral flow in the study of topological phases of matter.Comment: v2: 47 pages, applications to physics expande

HIV diagnosis and disclosure

For those we interviewed the knowledge that either they or their partner had diagnosed HIV needed to be managed on both an individual and collective level. It impacted on how each partner saw themselves and also how they perceived the future of their relationship. This report begins by exploring how participants with diagnosed HIV became aware of their HIV status, and how they have tried to come to terms with it, before describing their decision making about sharing this status with their partner and their means of doing so. The thoughts and experiences of participants who had not disclosed their status are described. Finally it explores the reactions of the HIV negative or untested partners to disclosure, its impact on a personal level and how they sought to come to terms with this news

Protocol for a systematic review: understanding the motivations and barriers to uptake and use of female-initiated, primary biomedical HIV prevention technologies in sub-Saharan Africa.

BACKGROUND: Women in sub-Saharan Africa are disproportionately affected by high rates of HIV, yet relatively few products exist for female-initiated HIV prevention. New antiretroviral (ARV)-based prevention options could present opportunities for women to expand their HIV prevention choices; however, acceptability and adherence play a key role in the effectiveness of these products and implementation is still in early stages. To better understand which HIV prevention options might best serve women in sub-Saharan Africa, how and why, this review will explore qualitative evidence from clinical trials and implementation studies alike using a meta-ethnographic approach to synthesise data and interpret results. METHODS/DESIGN: This systematic review will use a meta-ethnographic approach to analyse qualitative data extracted from multiple studies featuring actual use of female-initiated technologies for HIV prevention. The search strategy will be applied in seven databases and papers will be selected using strict inclusion and exclusion criteria. The review will closely follow the guidance set forth by preferred reporting items for systematic reviews and meta-analyses (PRISMA) and Centre for Reviews Dissemination (CRD) where the guidance applies to qualitative data. Two reviewers will review all papers during the paper selection phase, with consultation from a third reviewer to confirm consensus. All papers included in the review will be read and analysed by two reviewers. The final analysis will be conducted by three primary reviewers with additional input from all other authors. DISCUSSION: With new HIV prevention technologies currently in early implementation phases and still more on the horizon, there is much to learn about how best these products may be delivered. A review such as this could help to inform the real-world implementation of the next wave of new HIV prevention technologies such as ARV-based oral pre-exposure prophylaxis (PrEP)

A Primer on Metagenomics

Metagenomics is a discipline that enables the genomic study of uncultured microorganisms. Faster, cheaper sequencing technologies and the ability to sequence uncultured microbes sampled directly from their habitats are expanding and transforming our view of the microbial world. Distilling meaningful information from the millions of new genomic sequences presents a serious challenge to bioinformaticians. In cultured microbes, the genomic data come from a single clone, making sequence assembly and annotation tractable. In metagenomics, the data come from heterogeneous microbial communities, sometimes containing more than 10,000 species, with the sequence data being noisy and partial. From sampling, to assembly, to gene calling and function prediction, bioinformatics faces new demands in interpreting voluminous, noisy, and often partial sequence data. Although metagenomics is a relative newcomer to science, the past few years have seen an explosion in computational methods applied to metagenomic-based research. It is therefore not within the scope of this article to provide an exhaustive review. Rather, we provide here a concise yet comprehensive introduction to the current computational requirements presented by metagenomics, and review the recent progress made. We also note whether there is software that implements any of the methods presented here, and briefly review its utility. Nevertheless, it would be useful if readers of this article would avail themselves of the comment section provided by this journal, and relate their own experiences. Finally, the last section of this article provides a few representative studies illustrating different facets of recent scientific discoveries made using metagenomics

Family Violence Within LGBTQ Communities in Australia: Intersectional Experiences and Associations with Mental Health Outcomes

BackgroundWhile prior research has documented intimate partner violence (IPV) and family of origin violence (FOV) experienced by LGBTQ communities at rates at least comparable to heterosexual and/or cisgender populations, little knowledge exists of how this experience occurs within intersections of these communities and who is most at risk.MethodsThis study utilised data from a from a large nationwide Australian survey of the health and wellbeing of 6835 LGBTQ adults aged 18 + years. Multivariable logistic regression analyses were conducted to identify individual factors associated with reporting ever having experienced FOV or IPV.ResultsIn total, 2675 (43.18%) participants reported ever experiencing FOV and 3716 (60.7%) reported ever experiencing IPV. Non-binary people, cisgender women, and trans men were most likely to have experienced FOV. Non-binary people and cisgender women were most likely to experience IPV. Participants aged 55 + years (compared to 18–24 years) were less likely to have experienced FOV, while the likelihood of experiencing IPV increased with age. Education was associated with both FOV and IPV (highest among the non-university tertiary educated). Having a moderate or severe disability and ever experiencing homelessness were associated with a greater likelihood of experiencing FOV and IPV. Recent experiences of suicidal ideation, suicide attempt and high/very high psychological distress were associated with experiences of FOV and IPV.ConclusionsThis new knowledge regarding the factors that identify LGBTQ people at greater risk of family or intimate partner violence can ensure the tailoring of family violence practice and policy to those most in need