5,854 research outputs found
Recommended from our members
Effect of linear energy transfer (LET) on complexity of alpha-particle-induced chromosome aberrations in human CD34+ cells.
The aim of this study was to assess the relative influence of linear energy transfer (LET) of α-particles on chromosome aberration complexity in the absence of significant other track structure differences. To do this we irradiated human haemopoietic stem cells (CD34+) with The aim of this study was to assess the relative influence of linear energy transfer (LET) of α-particles of various incident LET values (110 - 152 keV/µm, with mean LETs through the cell of 119 – 182 keV/µm) at an equi-fluence of approximately 1 α-particle/cell and assayed for chromosome aberrations by m-FISH. Based on a single harvest time to collect early division mitosis , complex aberrations were observed at comparable frequencies irrespective of incident LET, however when expressed as a proportion of the total exchanges detected, their occurrence was seen to increase with increasing LET. Cycle analysis to predict theoretical DNA double strand break rejoining cycles was also carried out on all complex chromosome aberrations detected. By doing this we found that the majority of complex aberrations are formed in single non-reducible cycles that involve just 2 or 3 different chromosomes and 3 or 4 different breaks. Each non-reducible cycle is suggested to represent ‘an area’ of finite size within the nucleus where double strand break repair occurs. We suggest that local density of damage induced and proximity of independent repair areas within the interphase nucleus determine the complexity of aberration resolved in metaphase. Overall, the most likely outcome of a single nuclear traversal of a single α-particle in CD34+ cells is a single chromosome aberration per damaged cell. As the incident LET of the α-particle increases, the likelihood of this aberration being classed as complex is greater
Forecasting the severity of the Newfoundland iceberg season using a control systems model
The iceberg hazard for the Grand Banks area to the east of Newfoundland varies dramatically from one year to the next. In some years no icebergs penetrate south of 48°N, while in others well over 1000 icebergs enter the main shipping lanes between Europe and NE North America. Advance knowledge of this seasonal hazard would have major implications for ship routing, as well as the resources required for maintaining an effective ice hazard service. Here, a Windowed Error Reduction Ratio control system identification approach is used to forecast the severity of the 2018 iceberg season off Newfoundland, in terms of the predicted number of icebergs crossing 48°N, as well as to hindcast iceberg numbers for 2017. The best estimates are for 766 ± 297 icebergs crossing 48°N before the end of September 2017 and 685 ± 207 for 2018. These are both above the recent observed average of 592 icebergs for that date, and substantially so for 2017. Given the bimodal nature of the annual iceberg number, this means that our predictions for both 2017 and 2018 are for a high iceberg season, with a 71% level of confidence. However, it is most likely that the 2018 iceberg numbers will be somewhat less than 1000, while our higher hindcast for 2017 is consistent with the observed level of 1008. Our verification analysis, covering the 20-year period up to 2016, shows our model's correspondence to the high or low nature of the 48°N iceberg numbers is statistically robust to the 0.05% level, with a skill level of 80%
Weather influences feed intake and feed efficiency in a temperate climate
A key goal for livestock science is to ensure that food production meets the needs of an increasing global population. Climate change may heighten this challenge through increases in mean temperatures and in the intensity, duration, and spatial distribution of extreme weather events, such as heat waves. Under high ambient temperatures, livestock are expected to decrease dry matter intake (DMI) to reduce their metabolic heat production. High yielding dairy cows require high DMI to support their levels of milk production, but this may increase susceptibility to heat stress. Here, we tested how feed intake and the rate of converting dry matter to milk (feed efficiency, FE) vary in response to natural fluctuations in weather conditions in a housed experimental herd of lactating Holstein Friesians in the United Kingdom. Cows belonged to 2 lines: those selected for high genetic merit for milk traits (select) and those at the UK average (control). We predicted that (1) feed intake and FE would vary with an index of temperature and humidity (THI), wind speed, and the number of hours of sunshine, and that (2) the effects of (1) would depend on the cows' genetic merit. Animals received a mixed ration, available ad libitum, from automatic feed measurement gates. Using >73,000 daily feed intake and FE records from 328 cows over 8 yr, we found that select cows produced more fat- and protein-corrected milk, and had higher DMI and FE than controls. Cows of both lines decreased DMI and fat- and protein-corrected milk but, importantly, increased FE as THI increased. This suggests that improvements in the efficiency of converting feed to milk may partially offset the costs of reduced milk yield owing to a warmer climate, at least under conditions of mild heat stress. The rate of increase in FE with THI was steeper in select cows than in controls, which raises the possibility that select cows use more effective coping tactics. This is, to our knowledge, the first longitudinal study on the effects of weather on FE. Understanding how weather influences feed intake and efficiency can help us to develop management and selection practices that optimize productivity under unfavorable weather conditions. This will be an important aspect of climate resilience in future
Purchasing online journal access for a hospital medical library: how to identify value in commercially available products
BACKGROUND: Medical practice today requires evaluating large amounts of information which should be available at all times. This information is found most easily in a digital form. Some information has already been evaluated for validity (evidence based medicine sources) and some is in unevaluated form (paper and online journals). In order to improve access to digital information, the School of Clinical Medicine and Research at the University of the West Indies and Queen Elizabeth Hospital decided to enhance the library by offering online full text medical articles and evidence based medicine sources. The aim of this paper is to evaluate the relative value of online journal commercial products available for a small hospital and medical school library. METHODS: Three reference standards were chosen to represent the ideal list of core periodicals for a broad range of medical care: 2 Brandon/Hill selected lists of journals for the small medical library (BH and BH core) and the academic medical library core journal collection chosen for the Florida State University College of Medicine Medical Library. Six commercially available collections were compared to the reference standards and to the current paper journal subscription list as regards to number of journals matched and cost per journal matched. Ease of use and presence of secondary sources were also considered. RESULTS: The cost per journal matched ranged from US 81. Because of their low subscription prices, the Biomedical Reference Collection and Proquest products were the most cost beneficial. However, they provided low coverage of the ideal lists (12 – 17% and 21–32% respectively) and contained significant embargoes on current editions, were not user friendly and contained no secondary sources. The Ovid Brandon/Hill Plus Collection overcame these difficulties but had a much higher cost-benefit range while providing higher coverage of the ideal lists (14–47%). CONCLUSION: After considering costs, benefits, ease of use, embargoes, presence of secondary sources (ACP Journal Club, DARE), the Ovid Brandon/Hill Plus Collection was the best choice for our hospital considering our budget. However, the option to individually select our own journal list from Ovid and pay per journal has a certain appeal as well
Measuring attitude towards Buddhism and Sikhism : internal consistency reliability for two new instruments
This paper describes and discusses the development and empirical properties of two new
24-item scales – one measuring attitude toward Buddhism and the other measuring attitude
toward Sikhism. The scale is designed to facilitate inter-faith comparisons within the
psychology of religion alongside the well-established Francis Scale of Attitude toward
Christianity. Data were obtained from a multi-religious sample of 369 school pupils aged
between 13 and 15 in London. Application of the two scales demonstrated that adolescents
had a more positive attitude to Buddhism than Sikhism. The findings confirm the reliability
of the scales and commend them for further use
Infectious Disease Ontology
Technological developments have resulted in tremendous increases in the volume and diversity of the data and information that must be processed in the course of biomedical and clinical research and practice. Researchers are at the same time under ever greater pressure to share data and to take steps to ensure that data resources are interoperable. The use of ontologies to annotate data has proven successful in supporting these goals and in providing new possibilities for the automated processing of data and information. In this chapter, we describe different types of vocabulary resources and emphasize those features of formal ontologies that make them most useful for computational applications. We describe current uses of ontologies and discuss future goals for ontology-based computing, focusing on its use in the field of infectious diseases. We review the largest and most widely used vocabulary resources relevant to the study of infectious diseases and conclude with a description of the Infectious Disease Ontology (IDO) suite of interoperable ontology modules that together cover the entire infectious disease domain
Interventions for stroke rehabilitation: analysis of the research contained in the OTseeker evidence database
Purpose: To analyse the stroke content in OTseeker in terms of the quantity of the research evidence, the quality of the randomised controlled trials (RCTs), and the types of interventions and outcome measures used. Method: A survey of stroke-related content in the OTseeker database was conducted in 2007. The year of publication and intervention categories used in each stroke-related RCT and systematic review (SR) were recorded. The internal validity of RCTs using the PEDro scale (partitioned) and the outcome measures used were also recorded. Results: Of the 4,369 articles indexed on OTseeker, 452 (10.3%) related to stroke were conducted between 1979 and 2006. The five most frequently studied intervention categories were movement training (43.2%), models of service delivery (31.2%), physical modalities/orthotics/splinting (30.1%), exercise/stretching/strength training (19.5%), and skill acquisition/training (9.3%). Random allocation (96.1%) was the most frequently satisfied internal validity criterion and therapist blinding (3.1%) was least often satisfied. The five most frequently used outcome measurement categories were basic and extended activities of daily living (70.1%), hand and upper limb function (56.1%), walking/gait (44.1%), movement/motor function (32.7%), and quality of life/general overall health (27.9%). Conclusion: The stroke-related content on OTseeker is useful for allied health professionals. This study highlights a need for better definitions of interventions and consensus about the best outcome measures. Few interventions or outcome measures were participation focused
Troubling "understanding mathematics-in-depth": Its role in the identity work of student-teachers in England
Copyright @ The Author(s) 2013. This article is published with open access at Springerlink.comThis article has been made available through the Brunel Open Access Publishing Fund.In this paper, we focus on an initiative in England devised to prepare non-mathematics graduates to train as secondary mathematics teachers through a 6-month Mathematics Enhancement Course (MEC) to boost their subject knowledge. The course documentation focuses on the need to develop “understanding mathematics in-depth” in students in order for them to become successful mathematics teachers. We take a poststructural approach, so we are not interested in asking what such an understanding is, about the value of this approach or about the effectiveness of the MECs in developing this understanding in their participants. Instead we explore what positions this discourse of “understanding mathematics in-depth” makes available to MEC students. We do this by looking in detail at the “identity work” of two students, analysing how they use and are used by this discourse to position themselves as future mathematics teachers. In doing so, we show how even benign-looking social practices such as “understanding mathematics in-depth” are implicated in practices of inclusion and exclusion. We show this through detailed readings of interviews with two participants, one of whom fits with the dominant discourses in the MEC and the other who, despite passing the MEC, experiences tensions between her national identity work and MEC discourses. We argue that it is vital to explore “identity work” within teacher education contexts to ensure that becoming a successful mathematics teacher is equally available to all.King’s College Londo
Prescribing practices of primary-care veterinary practitioners in dogs diagnosed with bacterial pyoderma
Concern has been raised regarding the potential contributions of veterinary antimicrobial use to increasing levels of resistance in bacteria critically important to human health. Canine pyoderma is a frequent, often recurrent diagnosis in pet dogs, usually attributable to secondary bacterial infection of the skin. Lesions can range in severity based on the location, total area and depth of tissue affected and antimicrobial therapy is recommended for resolution. This study aimed to describe patient signalment, disease characteristics and treatment prescribed in a large number of UK, primary-care canine pyoderma cases and to estimate pyoderma prevalence in the UK vet-visiting canine population
Targeting TLR4 during vaccination boosts MAdCAM-1+ lymphoid stromal cell activation and promotes the aged germinal center response
The failure to generate enduring humoral immunity after vaccination is a hallmark of advancing age. This can be attributed to a reduction in the germinal center (GC) response, which generates long-lived antibody-secreting cells that protect against (re)infection. Despite intensive investigation, the primary cellular defect underlying impaired GCs in aging has not been identified. Here, we used heterochronic parabiosis to demonstrate that GC formation was dictated by the age of the lymph node (LN) microenvironment rather than the age of the immune cells. Lymphoid stromal cells are a key determinant of the LN microenvironment and are also an essential component underpinning GC structure and function. Using mouse models, we demonstrated that mucosal adressin cell adhesion molecule-1 (MAdCAM-1)-expressing lymphoid stromal cells were among the first cells to respond to NP-KLH + Alum immunization, proliferating and up-regulating cell surface proteins such as podoplanin and cell adhesion molecules. This response was essentially abrogated in aged mice. By targeting TLR4 using adjuvants, we improved the MAdCAM-1+ stromal cell response to immunization. This correlated with improved GC responses in both younger adult and aged mice, suggesting a link between stromal cell responses to immunization and GC initiation. Using bone marrow chimeras, we also found that MAdCAM-1+ stromal cells could respond directly to TLR4 ligands. Thus, the age-associated defect in GC and stromal cell responses to immunization can be targeted to improve vaccines in older people
- …