1,731 research outputs found

    A period of calm in Scottish seas: a comprehensive study of ΔR values for the northern British Isles coast and the consequent implications for archaeology and oceanography

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    The Marine Radiocarbon Reservoir Effect (MRE) is a 14C age offset between contemporaneous marine- and terrestrially-derived carbon. In Northern Hemisphere surface waters it is of the order of 400 years but temporal and spatial deviations, known as ΔR, occur. This study provides a comprehensive dataset of 21 ΔR and MRE values for the east coast of Scotland and 21 recalculated values for the west coast of Scotland and Ireland, for the period c. 3500 BC to 1450 AD. They are presented as mean, site-specific ΔR and MRE values, together with their associated uncertainties, calculated as standard errors for predicted values. The ΔR values range from -320 ± 35 to +150 ± 28 14C years and show no spatial or temporal trends. The MRE values range from 59 ± 40 to 531 ± 26, show an almost identical distribution pattern to the ΔR values and again show no spatial or temporal trends. Results show that ΔR values calculated for a single site using statistically indistinguishable groups of terrestrial and marine radiocarbon age measurements can produce variability of up to 225 14C years. ΔR is an important factor in the accurate calibration of samples containing marine-derived carbon for archaeological interpretation but is often also used as an indicator of changes in 14C specific activity of the oceans, and therefore a proxy for changes in ocean circulation and/or climate. Using the methods outlined in this paper, it is apparent that ΔR values for the northern part of the British Isles have been relatively stable, within our ability to quantify non-random variation in the data. The fact that significant climatic shifts have been recorded during this time, yet these are not visible in the ΔR data, presents a cautionary tale regarding the use of ΔR to infer large-scale oceanographic or climatic changes. Upon the exclusion of 5 outliers from the 42 values, the remaining ΔR values are statistically indistinguishable from one another and range from -142 ± 61 to +40 ± 47 14C years. 34 of these values are from Scottish archaeological sites and can be combined to produce a mean value for Scotland of -47 ± 52 14C years for the period 3500 BC to 1450 AD, to be used only in the absence of site- and period-specific data

    <sup>14</sup>C AMS at SUERC: improving QA data from the 5 MV tandem AMS and 250 kV SSAMS

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    In 2003, a National Electrostatics Corporation (NEC) 5MV tandem accelerator mass spectrometer was installed at SUERC, providing the radiocarbon laboratory with 14C measurements to 4–5‰ repeatability. In 2007, a 250kV single-stage accelerator mass spectrometer (SSAMS) was added to provide additional 14C capability and is now the preferred system for 14C analysis. Changes to the technology and to our operations are evident in our copious quality assurance data: typically, we now use the 134-position MC-SNICS source, which is filled to capacity. Measurement of standards shows that spectrometer running without the complication of on-line δ13C evaluation is a good operational compromise. Currently, 3‰ 14C/13C measurements are routinely achieved for samples up to nearly 3 half-lives old by consistent sample preparation and an automated data acquisition algorithm with sample random access for measurement repeats. Background and known-age standard data are presented for the period 2003–2008 for the 5MV system and 2007–2008 for the SSAMS, to demonstrate the improvements in data quality

    The low recombining pericentromeric region of barley restricts gene diversity and evolution but not gene expression

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    The low-recombining pericentromeric region of the barley genome contains roughly a quarter of the genes of the species, embedded in low-recombining DNA that is rich in repeats and repressive chromatin signatures. We have investigated the effects of pericentromeric region residency upon the expression, diversity and evolution of these genes. We observe no significant difference in average transcript level or developmental RNA specificity between the barley pericentromeric region and the rest of the genome. In contrast, all of the evolutionary parameters studied here show evidence of compromised gene evolution in this region. First, genes within the pericentromeric region of wild barley show reduced diversity and significantly weakened purifying selection compared with the rest of the genome. Second, gene duplicates (ohnolog pairs) derived from the cereal whole-genome duplication event ca. 60MYa have been completely eliminated from the barley pericentromeric region. Third, local gene duplication in the pericentromeric region is reduced by 29% relative to the rest of the genome. Thus, the pericentromeric region of barley is a permissive environment for gene expression but has restricted gene evolution in a sizeable fraction of barley's genes

    The effects of a single whole-body cryotherapy exposure on physiological, performance and perceptual responses of professional academy soccer players following repeated sprint exercise

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    In professional youth soccer players, the physiological, performance and perceptual effects of a single whole body cryotherapy (WBC) session performed shortly after repeated sprint exercise were investigated. In a randomized, counter-balanced and crossover design, 14 habituated English Premier League academy soccer players performed 15 x 30 m sprints (each followed by a 10 m forced deceleration) on two occasions. Within 20 min of exercise cessation, players entered a WBC chamber (Cryo: 30 s at -60°C, 120 s at -135°C) or remained seated (Con) indoors in temperate conditions (~25°C). Blood and saliva samples, peak power output (countermovement jump) and perceptual indices of recovery and soreness were assessed pre-exercise and immediately, 2 h and 24 h post exercise. When compared to Con, a greater testosterone response was observed at 2 h (+32.5 ± 32.3 pg·ml-1, +21%) and 24 h (+50.4 ± 48.9 pg·ml-1, +28%) post-exercise (both P=0.002) in Cryo (trial x treatment interaction: P=0.001). No between trial differences were observed for other salivary (cortisol and testosterone/cortisol ratio), blood (lactate and Creatine Kinase), performance (peak power output) or perceptual (recovery or soreness) markers (all trial x treatment interactions: P>0.05); all of which were influenced by exercise (time effects: all P<0.05). A single session of WBC performed within 20 min of repeated sprint exercise elevated testosterone concentrations for 24 h but did not affect any other performance, physiological or perceptual measurements taken. While unclear, WBC may be efficacious for professional soccer players during congested fixture periods

    Canopy nitrogen, carbon assimilation, and albedo in temperate and boreal forests: Functional relations and potential climate feedbacks

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    The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth\u27s climate system has been considered. Despite this, few studies have included continuous variation in plant N status as a driver of broad-scale carbon cycle analyses. This is partly because of uncertainties in how leaf-level physiological relationships scale to whole ecosystems and because methods for regional to continental detection of plant N concentrations have yet to be developed. Here, we show that ecosystem CO2 uptake capacity in temperate and boreal forests scales directly with whole-canopy N concentrations, mirroring a leaf-level trend that has been observed for woody plants worldwide. We further show that both CO2 uptake capacity and canopy N concentration are strongly and positively correlated with shortwave surface albedo. These results suggest that N plays an additional, and overlooked, role in the climate system via its influence on vegetation reflectivity and shortwave surface energy exchange. We also demonstrate that much of the spatial variation in canopy N can be detected by using broad-band satellite sensors, offering a means through which these findings can be applied toward improved application of coupled carbon cycle–climate models

    Western Pacific hydroclimate linked to global climate variability over the past two millennia

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    Interdecadal modes of tropical Pacific ocean-atmosphere circulation have a strong influence on global temperature, yet the extent to which these phenomena influence global climate on multicentury timescales is still poorly known. Here we present a 2,000-year, multiproxy reconstruction of western Pacific hydroclimate from two speleothem records for southeastern Indonesia. The composite record shows pronounced shifts in monsoon rainfall that are antiphased with precipitation records for East Asia and the central-eastern equatorial Pacific. These meridional and zonal patterns are best explained by a poleward expansion of the Australasian Intertropical Convergence Zone and weakening of the Pacific Walker circulation (PWC) between ~1000 and 1500 CE Conversely, an equatorward contraction of the Intertropical Convergence Zone and strengthened PWC occurred between ~1500 and 1900 CE. Our findings, together with climate model simulations, highlight the likelihood that century-scale variations in tropical Pacific climate modes can significantly modulate radiatively forced shifts in global temperature

    Support at Home: Interventions to Enhance Life in Dementia (SHIELD) – evidence, development and evaluation of complex interventions

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    Background: Dementia is a national priority and this research addresses the Prime Minister’s commitment to dementia research as demonstrated by his 2020 challenge and the new UK Dementia Research Institute. In the UK > 800,000 older people have dementia. It has a major impact on the lives of people with dementia themselves, on the lives of their family carers and on services, and costs the nation £26B per year. Pharmacological cures for dementias such as Alzheimer’s disease are not expected before 2025. If no cure can be found, the ageing demographic will result in 2 million people living with dementia by 2050. People with dementia lose much more than just their memory and their daily living skills; they can also lose their independence, their dignity and status, their confidence and morale, and their roles both within the family and beyond. They can be seen as a burden by society, by their families and even by themselves, and may feel unable to contribute to society. This programme of research aims to find useful interventions to improve the quality of life of people with dementia and their carers, and to better understand how people with dementia can be supported at home and avoid being admitted to hospital. Objectives: (1) To develop and evaluate the maintenance cognitive stimulation therapy (MCST) for people with dementia; (2) to develop the Carer Supporter Programme (CSP), and to evaluate the CSP and Remembering Yesterday, Caring Today (RYCT) for people with dementia both separately and together in comparison with usual care; and (3) to develop a home treatment package (HTP) for dementia, to field test the HTP in practice and to conduct an exploratory trial. Methods: (1) The MCST programme was developed for people with dementia based on evidence and qualitative work. A randomised controlled trial (RCT) [with a pilot study of MCST plus acetylcholinesterase inhibitors (AChEIs)] compared MCST with cognitive stimulation therapy (CST) only. The MCST implementation study conducted a trial of outreach compared with usual care, and assessed implementation in practice. (2) The CSP was developed based on existing evidence and the engagement of carers of people with dementia. The RCT (with internal pilot) compared the CSP and reminiscence (RYCT), both separately and in combination, with usual care. (3) A HTP for dementia, including the most promising interventions and components, was developed by systematically reviewing the literature and qualitative studies including consensus approaches. The HTP for dementia was evaluated in practice by conducting in-depth field testing. Results: (1) Continuing MCST improved quality of life and improved cognition for those taking AChEIs. It was also cost-effective. The CST implementation studies indicated that many staff will run CST groups following a 1-day training course, but that outreach support helps staff go on to run maintenance groups and may also improve staff sense of competence in dementia care. The study of CST in practice found no change in cognition or quality of life at 8-month follow-up. (2) The CSP/RYCT study found no benefits for family carers but improved quality of life for people with dementia. RYCT appeared beneficial for the quality of life of people with dementia but at an excessively high cost. (3) Case management for people with dementia reduces admissions to long-term care and reduces behavioural problems. In terms of managing crises, staff suggested more costly interventions, carers liked education and support, and people with dementia wanted family support, home adaptations and technology. The easy-to-use home treatment manual was feasible in practice to help staff working in crisis teams to prevent hospital admissions for people with dementia. Limitations: Given constraints on time and funding, we were unable to compete the exploratory trial of the HTP package or to conduct an economic evaluation. Future research: To improve the care of people with dementia experiencing crises, a large-scale clinical trial of the home treatment manual is needed. Conclusion: There is an urgent need for effective psychosocial interventions for dementia. MCST improved quality of life and was cost-effective, with benefits to cognition for those on AChEIs. MCST was feasible in practice. Both CSP and RYCT improved the quality of life of people with dementia, but the overall costs may be too high. The HTP was useful in practice but requires evaluation in a full trial. Dementia care research may improve the lives of millions of people across the world. Trial registrations: Current Controlled Trials ISRCTN26286067 (MCST), ISRCTN28793457 (MCST implementation) and ISRCTN37956201 (CSP/RYCT). Funding: This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 5, No. 5. See the NIHR Journals Library website for further project information

    Bhlhe40 controls cytokine production by T cells and is essential for pathogenicity in autoimmune neuroinflammation

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    T(H)1 and T(H)17 cells mediate neuroinflammation in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Pathogenic T(H) cells in EAE must produce the pro-inflammatory cytokine granulocyte-macrophage colony stimulating factor (GM-CSF). T(H) cell pathogenicity in EAE is also regulated by cell-intrinsic production of the immunosuppressive cytokine interleukin 10 (IL-10). Here, we demonstrate that mice deficient for the basic helix-loop-helix (bHLH) transcription factor Bhlhe40 (Bhlhe40(−/−)) are resistant to the induction of EAE. Bhlhe40 is required in vivo in a T cell-intrinsic manner, where it positively regulates the production of GM-CSF and negatively regulates the production of IL-10. In vitro, GM-CSF secretion is selectively abrogated in polarized Bhlhe40(−/−) T(H)1 and T(H)17 cells, and these cells show increased production of IL-10. Blockade of IL-10 receptor in Bhlhe40(−/−) mice renders them susceptible to EAE. These findings identify Bhlhe40 as a critical regulator of autoreactive T cell pathogenicity

    An evaluation of post-registration neuroscience focused education and neuroscience nurses' perceived educational needs

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    Background People with complex neurological conditions require co-ordinated care provided by nurses educated in meeting service needs, understanding the pathophysiological processes of disease and the preparation to care for those with complex needs. However, evidence suggests that neuroscience specific education provision is largely unregulated and set outside of a cohesive professional development context. Furthermore, it largely seems to only address the induction phase into working within neurosciences. Objectives To evaluate the nature of post-registration neuroscience focused education across Europe and neuroscience nurses' perceived educational needs. Methods Post qualifying nurses working in the field of neurosciences were invited to complete a self-reported 29-item on-line questionnaire that contained closed and open-ended questions exploring professional background, clinical and educational experience, educational opportunities available to them and their perspectives on their educational needs. Results 154 participants from fourteen countries across Europe completed the survey. 75% (n = 110) of respondents had undertaken neuroscience focused education with the most accessible education opportunities found to be conferences 77% (n = 96) and study days 69% (n = 86). Overall, 52.6% of courses were multidisciplinary in nature, and 47.4% were exclusively nursing. Most identified that their courses were funded by their employer (57%, n = 63) or partly funded by their employer. Results illustrate a significant variance across Europe, highlighting the need for more effective communication between neuroscience nurses across Europe. Implications for future education provision, recruitment/retention, and funding are discussed, resulting in recommendations for the future of neuroscience nursing. Conclusions This study, the largest of its kind to survey neuroscience nurses, illustrates the absence of a cohesive career development pathway for neuroscience nurses in Europe. Nurses need quality assured specialist education to deliver high quality appropriate healthcare
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