Holocene lowering of the Laurentide ice sheet affects North Atlantic gyre circulation and climate

The Laurentide ice sheet, which covered Canada during glacial periods, had a major influence on atmospheric circulation and surface climate, but its role in climate during the early Holocene (9–7 ka), when it was thinner and confined around Hudson Bay, is unclear. It has been suggested that the demise of the ice sheet played a role in the 8.2 ka event (an abrupt 1–3 °C Northern Hemisphere cooling lasting ~ 160 years) through the influence of changing topography on atmospheric circulation. To test this hypothesis, and to investigate the broader implications of changing ice sheet topography for climate, we analyse a set of equilibrium climate simulations with ice sheet topographies taken at 500 year intervals from 9.5 to 8.0 ka. Between 9.5 and 8.0 ka, our simulations show a 2 °C cooling south of Iceland and a 1 °C warming between 40° and 50°N in the North Atlantic. These surface temperature changes are associated with a weakening of the subtropical and subpolar gyres caused by a decreasing wind stress curl over the mid-North Atlantic as the ice sheet lowers. The climate response is strongest during the period of peak ice volume change (9.5–8.5 ka), but becomes negligible after 8.5 ka. The climatic effects of the Laurentide ice sheet lowering during the Holocene are restricted to the North Atlantic sector. Thus, topographic forcing is unlikely to have played a major role in the 8.2 ka event and had only a small effect on Holocene climate change compared to the effects of changes in greenhouse gases, insolation and ice sheet meltwater

Axial acoustic field barrier for fluidic particle manipulation

An acoustic field barrier integrated within a flow tubing system to achieve high-throughput separation of particles in fluid is reported in this work. We investigate the axial acoustic field of a piezo-tube with an inside diameter of 34 mm, a length of 25 mm, and an operating frequency of 1.15 MHz. Energy concentrates within the tube, and leakage at the ends provides a sharp monotonic acoustic pressure field within a fluidic circuit. This process is not the conventional standing wave mechanism; instead, the geometry produces a spatially stable filtering action without fouling. This powerful filtering action is confirmed theoretically via a COMSOL simulation and demonstrated experimentally by concentrating suspensions of 5 μm proteoglycan tracer particles at a flow rate of 20 ml/min: The corresponding acoustic contrast factor is 0.243, and the trapping force is 11pN. This tube geometry tackles the limitations of microfluidic standing wave based acoustic concentrators, namely, complex extraction, low-throughput, and distributed focus, by harnessing a stable monotonic field profile

Acidification in the Cairngorms and Lochnagar: a palaeoecological assessment

Sensitive lakes in areas of the United Kingdom with moderate to high sulphur deposition have been acidified since the middle of the nineteenth century- (Battarbee et al. 1988). Regions such as Galloway, south west Scotland (eg. Flower and Battarbee 1983, Flower et al. 1987), Wales (eg. Battarbee et al. 1988, Fritz et aL 1990), Cumbria (eg. Battarbee et al 1988, Atkinson and Haworth 1990), and Rannoch Moor in the central Scottish Highlands (eg. Flower et al 1988) have been affected. This study extends the geographical survey of lake acidification to the Caimgorm and Lochnagar regions of north east Scotland (Figure 1). The Caimgorms and Lochnagar are areas of considerable conservation value, forming the largest single area of land over 1000 m in the UK. The Caimgorm mountain plateau is a National Nature Reserve, noted for its alpine flora and fauna, whilst the Lochnagar range is a Scottish Wildlife Trust reserve. A secondary- aim of the study was to evaluate the 11land-use 11 hypothesis (eg. Rosenqvist 1977, 1978, 1981) as a mechanism for lake acidification by examining high altitude sites with no active land-management. Sites selected are all remote, lie above the tree line and have undisturbed catchments. Lochnagar and the Caimgorms are situated on sensitive granite geology (Kinniburgh and Edmunds 1986, Wells et al. 1986) in an area of moderate acid deposition (c. 0.95 g S yr-1 ). It can be predicted that sensitive lakes in this area (those having Ca2 + values of <60 μeq i-1 ) will have acidified (Battarbee 1989)

Hospital-based preventative interventions for people experiencing homelessness in high-income countries: A systematic review

BACKGROUND: People experiencing homelessness have significant unmet needs and high rates of unplanned care. We aimed to describe preventative interventions, defined in their broadest sense, for people experiencing homelessness in a hospital context. Secondary aims included mapping outcomes and assessing intervention effectiveness. METHODS: We searched online databases (MEDLINE, Embase, PsycINFO, HMIC, CINAHL, Web of Science, Cochrane Library) from 1999–2019 and conducted backward and forward citation searches to 31 December 2020 (PROSPERO CRD42019154036). We included quantitative studies in emergency and inpatient settings measuring health or social outcomes for adults experiencing homelessness in high income countries. We assessed rigour using the “Quality Assessment Tool for Quantitative Studies” and summarised findings using descriptive quantitative methods, a binomial test, a Harvest Plot, and narrative synthesis. We used PRISMA and SWiM reporting guidelines. FINDINGS: Twenty-eight studies identified eight intervention types: care coordination (n=18); advocacy, support, and outreach (n=13); social welfare assistance (n=13); discharge planning (n=12); homelessness identification (n=6); psychological therapy and treatment (n=6); infectious disease prevention (n=5); and screening, treatment, and referrals (n=5). The evidence strength was weak (n=16) to moderate (n=10), with two high quality randomised controlled trials. We identified six outcome categories with potential benefits observed for psychosocial outcomes, including housing (11/13 studies, 95%CI=54.6–98.1%, p=0.023), healthcare use (14/17, 56.6–96.2%, p=0.013), and healthcare costs (8/8, 63.1–100%, p=0.008). Benefits were less likely for health outcomes (4/5, 28.3–99.5%, p=0.375), integration with onward care (2/4, 6.8–93.2%, p=1.000), and feasibility/acceptability (5/6, 35.9–99.6%, p=0.219), but confidence intervals were very wide. We observed no harms. Most studies showing potential benefits were multi-component interventions. INTERPRETATION: Hospital-based preventative interventions for people experiencing homelessness are potentially beneficial, but more rigorous research is needed. In the context of high needs and extreme inequities, policymakers and healthcare providers may consider implementing multi-component preventative interventions. FUNDING: SL is supported by an NIHR Clinical Doctoral Research Fellowship (ICA-CDRF-2016-02-042). JD is supported by an NIHR School of Public Health Research Pre-doctoral Fellowship (NU-004252). RWA is supported by a Wellcome Clinical Research Career Development Fellowship (206602)

Genetic background influences tumour development in heterozygous Men1 knockout mice

Multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disorder caused by MEN1 germline mutations, is characterised by parathyroid, pancreatic and pituitary tumours. MEN1 mutations also cause familial isolated primary hyperparathyroidism (FIHP), a milder condition causing hyperparathyroidism only. Identical mutations can cause either MEN1 or FIHP in different families, thereby implicating a role for genetic modifiers in altering phenotypic expression of tumours. We therefore investigated the effects of genetic background and potential for genetic modifiers on tumour development in adult Men1+/- mice, which develop tumours of the parathyroids, pancreatic islets, anterior pituitary, adrenal cortex and gonads, that had been backcrossed to generate C57BL/6 and 129S6/SvEv congenic strains. A total of 275 Men1+/- mice, aged 5–26 months were macroscopically studied, and this revealed that genetic background significantly influenced the development of pituitary, adrenal and ovarian tumours, which occurred in mice over 12 months of age and more frequently in C57BL/6 females, 129S6/SvEv males and 129S6/SvEv females, respectively. Moreover, pituitary and adrenal tumours developed earlier, in C57BL/6 males and 129S6/SvEv females, respectively, and pancreatic and testicular tumours developed earlier in 129S6/SvEv males. Furthermore, glucagon-positive staining pancreatic tumours occurred more frequently in 129S6/SvEv Men1+/- mice. Whole genome sequence analysis of 129S6/SvEv and C57BL/6 Men1+/- mice revealed >54,000 different variants in >300 genes. These included, Coq7, Dmpk, Ccne2, Kras, Wnt2b, Il3ra and Tnfrsf10a, and qRT-PCR analysis revealed that Kras was significantly higher in pituitaries of male 129S6/SvEv mice. Thus, our results demonstrate that Kras and other genes could represent possible genetic modifiers of Men1