The symbiotic binary system RX Puppis: a possible recurrent nova with a Mira companion

We present an analysis of photometric and spectroscopic observations of the symbiotic binary system RX Pup with the aims of developing a reliable binary for the system and identifying mechanisms responsible for its spectacular activity. The binary is composed of a long-perod Mira variable surrounded by a thick dust shell and a hot white dwarf companion. The hot component produces practically all activity observed in the UV, optical and radio range, while variable obscuration of the Mira by circumstellar dust is responsible for long-term changes in the near-IR magnitudes. The observations show RX Pup underwent a nova-like eruption during the last three decades. The hot component contracted in radius at roughly constant luminosity from 1975 to 1986, and was the source of a strong stellar wind which prevented it from accreting material lost in the Mira wind. Around 1988/9 the hot component turned over in the HR diagram and by 1991 its luminosity had faded by a factor of about 30 with respect to the maximum plateau value and the hot wind had practically ceased. By 1995 the nova remnant started to accrete material from the Mira wind, as indicated by a general increase in intensity of the optical continuum and HI emission. The quiescent spectrum resembles the quiescent spectra of symbiotic recurrent novae, and its intensity indicates the hot component must accrete as much as about 1 per cent of the Mira wind, which is more or less the amount predicted by Bondi-Hoyle theory. The earliest observational records from the 1890s suggest that another nova-like eruption of RX Pup occurred around 1894.Comment: 23 pages, 12 figues, MNRAS - accepte

Young people with diabetes and their peers

Type 1 Diabetes (T1D) is amongst the most common form of chronic illness affecting young people in the UK. Self- management is crucial, but managing their T1D is often difficult for young people

CD8+ T Cell Immunity in Human Immunodeficiency Virus-1 (HIV-1) Infection

A detailed understanding of the immune response to human immunodeficiency virus (HIV)-1 infection is needed to inform preventative and therapeutic strategies against HIV-1. HIV-1 specific CD8+ T cells contribute to control of HIV-1 throughout infection and will likely be an important component of any vaccine approach; however, it remains unclear what mechanisms of CD8+ T cell function mediate viral control. To that end, we analyzed samples from an acutely HIV-1 infected cohort and from persons living with HIV-1 (PLWH) durably suppressed on antiretroviral therapy (ART) to investigate the HIV-1 specific T cell response. In the latter group, we also explored the existence of pre-ART escape in the latent replication-competent HIV-1 reservoir, which contributes to HIV-1 rebound and may limit the capacity of T cells to detect and clear virally infected cells. Our studies show that HIV-1 infection induces a dynamic and robust HIV-1 specific CD8+ T cell response, with a large breadth of response that negatively correlated with viral load set point. The primary HIV-1 specific CD8+ T cell response was both highly activated and cytotoxic, and waned with the establishment of viral load set point. While total memory CD8+ T cells also expressed this phenotype, this phenotype was far more variable in human cytomegalovirus (HCMV)-specific CD8+ T cells. In the context of PLWH on ART, we report that while HIV-1 specific T cell targeting of the HIV-1 proteome was similar to patterns reported in untreated HIV-1 infection, the overall magnitude of the HIV-1 specific T cell response was ~10 fold lower than in untreated HIV-1 infection but remained detectable and highly stable. Importantly, we also report that the majority (68%) of virus variants in the latent HIV-1 reservoir did not escape T cell recognition, and that escape frequently occurred in less conserved regions of HIV-1. Collectively, our data suggest that circulating T cells in PLWH on ART could be harnessed for HIV-1 curative approaches, and that T cell immunotherapies shifting HIV-1 specific T cells to conserved regions of HIV-1 may mitigate past and future viral escape from T cells and overcome population level immunogenicity.Doctor of Philosoph

Phonotactics, graphotactics and contrast:The history of Scots dental fricative spellings

The spelling conventions for dental fricatives in Anglic languages (Scots and English) have a rich and complex history. However, the various – often competing – graphemic representations (<þ>, <ð>, <y> and <th>, among others) eventually settled on one digraph, <th>, for all contemporary varieties, irrespective of the phonemic distinction between /ð/ and /θ/. This single representation is odd among the languages’ fricatives, which tend to use contrasting graphemes (cf. <f> vs <v> and <s> vs <z>) to represent contrastive voicing, a sound pattern that emerged nearly a millennium ago. Close examinations of the scribal practices for English in the late medieval period, however, have shown that northern texts had begun to develop precisely this type of distinction for dental fricatives as well. Here /ð/ was predominantly represented by <y> and /θ/ by <th> (Jordan 1925; Benskin 1982). In the late fifteenth and early sixteenth centuries, this ‘Northern System’ collapsed, due to the northward spread of a London-based convention using exclusively <th> (Stenroos 2004). This article uses a rich body of corpus evidence for fifteenth-century Scots to show that, north of the North, the phonemic distinction was more clearly mirrored by spelling conventions than in any contemporary variety of English. Indeed, our data for Older Scots local documents (1375–1500) show a pattern where <y> progressively spreads into voiced contexts, while <th> recedes into voiceless ones. This system is traced back to the Old English positional preferences for <þ> and <ð> via subsequent changes in phonology, graphemic repertoire and letter shapes. An independent medieval Scots spelling norm is seen to emerge as part of a developing, proto-standard orthographic system, only to be cut short in the sixteenth century by top-down anglicisation processes

Population differentiation at a regional scale in spadefoot toads: contributions of distance and divergent selective environments

The causes of population differentiation can provide insight into the origins of early barriers to gene flow. Two key drivers of population differentiation are geographic distance and local adaptation to divergent selective environments. When reproductive isolation arises because some populations of a species are under selection to avoid hybridization while others are not, population differentiation and even speciation can result. Spadefoot toad populations Spea multiplicata that are sympatric with a congener have undergone reinforcement. This reinforcement has resulted not only in increased reproductive isolation from the congener, but also in the evolution of reproductive isolation from nearby and distant conspecific allopatric populations. We used multiple approaches to evaluate the contributions of geographic distance and divergent selective environments to population structure across this regional scale in S. multiplicata, based on genotypes from six nuclear microsatellite markers. We compared groups of populations varying in both geographic location and in the presence of a congener. Hierarchical F-statistics and results from cluster analyses and discriminant analyses of principal components all indicate that geographic distance is the stronger contributor to genetic differentiation among S. multiplicata populations at a regional scale. However, we found evidence that adaptation to divergent selective environments also contributes to population structure. Our findings highlight how variation in the balance of evolutionary forces acting across a species’ range can lead to variation in the relative contributions of geographic distance and local adaptation to population differentiation across different spatial scales

Exploring how young people think about and respond to diabetes in their peers

Adolescence is a difficult time for people with diabetes and it is often accompanied by a deterioration in blood glucose control. This article looks at the effect the attitudes of peers can have on adolescents with diabetes. Three focus groups of 12–14-year-olds were asked about their knowledge of diabetes and were then presented with realistic vignettes about the condition, which they discussed. They then took part in a mythbusting session to help address misconceptions. The research team identified themes that emerged from the focus groups. Their findings suggest that a supportive peer network may be a valuable resource in good management of diabetes in young people. The research team suggest that more education about the condition is needed in schools and should be designed in collaboration with young people with diabetes

Visualising pre-standard spelling practice:Understanding the interchange of ‹ch(t)› and ‹th(t)› in Older Scots

No abstract available

Charting the rise and demise of a phonotactically motivated change in Scots

Although Old English [f] and [v] are represented unambiguously in Older Scots orthography by <f> and <v> (or <u>) in initial and morpheme-internal position, in morpheme-final position <f> and <v>/<u> appear to be used interchangeably for both of these Old English sounds. As a result, there is often a mismatch between the spellings and the etymologically expected consonant. This paper explores these spellings using a substantial database of Older Scots texts, which have been grapho-phonologically parsed as part of the From Inglis to Scots (FITS) project. Three explanations are explored for this apparent mismatch: (1) it was a spelling-only change; (2) there was a near merger of /f/ and /v/ in Older Scots; (3) final [v] devoiced in (pre-)Older Scots but this has subsequently been reversed. A close analysis of the data suggests that the Old English phonotactic constraint against final voiced fricatives survived into the pre-Literary Scots period, leading to automatic devoicing of any fricative that appeared in word-final position (a version of Hypothesis 3), and this, interacting with final schwa loss, gave rise to the complex patterns of variation we see in the Older Scots data. Thus, the devoicing of [v] in final position was not just a phonetically natural sound change, but also one driven by a pre-existing phonotactic constraint in the language. This paper provides evidence for the active role of phonotactic constraints in the development of sound changes, suggesting that phonotactic constraints are not necessarily at the mercy of the changes which conflict with them, but can be involved in the direction of sound change themselves

Keeping the Light On: Academic Librarians & Burnout (Conference Presentation)

There is substantial research about sources of burnout among academic librarians; however, very little addresses the impact of the local environment. Responding to regional and institutional shifts while still trying to uphold the values of librarianship such as providing confidential and free access to information can quickly lead to mental, emotional, and physical exhaustion, classic symptoms of burnout. A panel discussion was hosted at the Arkansas Library Association (ArLA) / Southeast Library Association (SELA) Joint Conference, on Saturday, October 14, 2023. Academic librarians from different Southern states discussed their local environments, their libraries’ responses to recent events, and their strategies for working through burnout. Some of the aspirational outcomes from the discussion were: recognition that burnout is a common experience; how to find ways to serve patrons despite fluctuating hurdles; and understanding how personal burnout can impact the entire library organization