297 research outputs found

    Recent advances on information transmission and storage assisted by noise

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    The interplay between nonlinear dynamic systems and noise has proved to be of great relevance in several application areas. In this presentation, we focus on the areas of information transmission and storage. We review some recent results on information transmission through nonlinear channels assisted by noise. We also present recent proposals of memory devices in which noise plays an essential role. Finally, we discuss new results on the influence of noise in memristors.Comment: To be published in "Theory and Applications of Nonlinear Dynamics: Model and Design of Complex Systems", Proceedings of ICAND 2012 (Springer, 2014

    The individual and combined effects of obesity- and ageing-induced systemic inflammation on human skeletal muscle properties.

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    BACKGROUND/OBJECTIVES: The purpose of this study was to determine whether circulating pro-inflammatory cytokines, elevated with increased fat mass and ageing, were associated with muscle properties in young and older people with variable adiposity. SUBJECTS/METHODS: Seventy-five young (18-49 yrs) and 67 older (50-80 yrs) healthy, untrained men and women (BMI: 17-49 kg/m(2)) performed isometric and isokinetic plantar flexor maximum voluntary contractions (MVCs). Volume (Vm), fascicle pennation angle (FPA), and physiological cross-sectional area (PCSA) of the gastrocnemius medialis (GM) muscle were measured using ultrasonography. Voluntary muscle activation (VA) was assessed using electrical stimulation. GM specific force was calculated as GM fascicle force/PCSA. Percentage body fat (BF%), body fat mass (BFM), and lean mass (BLM) were assessed using dual-energy X-ray absorptiometry. Serum concentration of 12 cytokines was measured using multiplex luminometry. RESULTS: Despite greater Vm, FPA, and PCSA (P0.05), while IL-8 correlated with VA in older but not young adults (r⩾0.378, P⩽0.027). TNF-alpha correlated with MVC, lean mass, GM FPA and maximum force in older adults (r⩾0.458; P⩽0.048). CONCLUSIONS: The age- and adiposity-dependent relationships found here provide evidence that circulating pro-inflammatory cytokines may play different roles in muscle remodelling according to the age and adiposity of the individual.International Journal of Obesity accepted article preview online, 29 August 2016. doi:10.1038/ijo.2016.151

    Eta Carinae -- Physics of the Inner Ejecta

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    Eta Carinae's inner ejecta are dominated observationally by the bright Weigelt blobs and their famously rich spectra of nebular emission and absorption lines. They are dense (n_e ~ 10^7 to 10^8 cm^-3), warm (T_e ~ 6000 to 7000 K) and slow moving (~40 km/s) condensations of mostly neutral (H^0) gas. Located within 1000 AU of the central star, they contain heavily CNO-processed material that was ejected from the star about a century ago. Outside the blobs, the inner ejecta include absorption-line clouds with similar conditions, plus emission-line gas that has generally lower densities and a wider range of speeds (reaching a few hundred km/s) compared to the blobs. The blobs appear to contain a negligible amount of dust and have a nearly dust-free view of the central source, but our view across the inner ejecta is severely affected by uncertain amounts of dust having a patchy distribution in the foreground. Emission lines from the inner ejecta are powered by photoionization and fluorescent processes. The variable nature of this emission, occurring in a 5.54 yr event cycle, requires specific changes to the incident flux that hold important clues to the nature of the central object.Comment: This is Chapter 5 in a book entitled: Eta Carinae and the Supernova Impostors, Kris Davidson and Roberta M. Humphreys, editors Springe

    Selenium Toxicity to Honey Bee (Apis mellifera L.) Pollinators: Effects on Behaviors and Survival

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    We know very little about how soil-borne pollutants such as selenium (Se) can impact pollinators, even though Se has contaminated soils and plants in areas where insect pollination can be critical to the functioning of both agricultural and natural ecosystems. Se can be biotransferred throughout the food web, but few studies have examined its effects on the insects that feed on Se-accumulating plants, particularly pollinators. In laboratory bioassays, we used proboscis extension reflex (PER) and taste perception to determine if the presence of Se affected the gustatory response of honey bee (Apis mellifera L., Hymenoptera: Apidae) foragers. Antennae and proboscises were stimulated with both organic (selenomethionine) and inorganic (selenate) forms of Se that commonly occur in Se-accumulating plants. Methionine was also tested. Each compound was dissolved in 1 M sucrose at 5 concentrations, with sucrose alone as a control. Antennal stimulation with selenomethionine and methionine reduced PER at higher concentrations. Selenate did not reduce gustatory behaviors. Two hours after being fed the treatments, bees were tested for sucrose response threshold. Bees fed selenate responded less to sucrose stimulation. Mortality was higher in bees chronically dosed with selenate compared with a single dose. Selenomethionine did not increase mortality except at the highest concentration. Methionine did not significantly impact survival. Our study has shown that bees fed selenate were less responsive to sucrose, which may lead to a reduction in incoming floral resources needed to support coworkers and larvae in the field. If honey bees forage on nectar containing Se (particularly selenate), reductions in population numbers may occur due to direct toxicity. Given that honey bees are willing to consume food resources containing Se and may not avoid Se compounds in the plant tissues on which they are foraging, they may suffer similar adverse effects as seen in other insect guilds

    A mixed methods inquiry: How dairy farmers perceive the value(s) of their involvement in an intensive dairy herd health management program

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    <p>Abstract</p> <p>Background</p> <p>Research has been scarce when it comes to the motivational and behavioral sides of farmers' expectations related to dairy herd health management programs. The objectives of this study were to explore farmers' expectations related to participation in a health management program by: 1) identifying important ambitions, goals and subjective well-being among farmers, 2) submitting those data to a quantitative analysis thereby characterizing perspective(s) of value added by health management programs among farmers; and 3) to characterize perceptions of farmers' goals among veterinarians.</p> <p>Methods</p> <p>The subject was initially explored by means of literature, interviews and discussions with farmers, herd health management consultants and researchers to provide an understanding (a concourse) of the research entity. The concourse was then broken down into 46 statements. Sixteen Danish dairy farmers and 18 veterinarians associated with one large nationwide veterinary practice were asked to rank the 46 statements that defined the concourse. Next, a principal component analysis was applied to identify correlated statements and thus families of perspectives between respondents. Q-methodology was utilized to represent each of the statements by one row and each respondent by one column in the matrix. A subset of the farmers participated in a series of semi-structured interviews to face validate the concourse and to discuss subjects like animal welfare, veterinarians' competences as experienced by the farmers and time constraints in the farmers' everyday life.</p> <p>Results</p> <p>Farmers' views could be described by four families of perspectives: Teamwork, Animal welfare, Knowledge dissemination, and Production. Veterinarians believed that farmers' primary focus was on production and profit, however, farmers' valued teamwork and animal welfare more.</p> <p>Conclusion</p> <p>The veterinarians in this study appear to focus too much on financial performance and increased production when compared to most of the participating farmers' expectations. On the other hand veterinarians did not focus enough on the major products, which farmers really wanted to buy, i.e. teamwork and animal welfare. Consequently, disciplines like sociology, economics and marketing may offer new methodological approaches to veterinarians as these disciplines have understood that accounting for individual differences is central to motivate change, i.e. 'know thy customer'.</p

    Cuidados prestados à mulher na visita domiciliar da “Primeira Semana de Saúde Integral”

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    Objetivo: Avaliar o cuidado prestado à mulher na visita domiciliar da “Primeira Semana de Saúde Integral”.Método: Estudo transversal realizado em serviço especializado do Recife, Pernambuco. Entre setembro e dezembro de 2013, 190 puérperas cadastradas na Estratégia Saúde da Família responderam a um questionário para verificar a existência de associação entre a visita domiciliar e as variáveis investigadas, utilizando o teste Qui-quadrado, com nível de confiança de 95%.Resultados: Predominou idade de até 29 anos (68,5%) e risco gestacional alto (59,5%), sendo 46,9% primíparas. Na primeira semana pós-alta, 42,1% receberam visita. Constatou-se associação entre atenção pré-natal em nível local e visita na primeira semana (p=0,049). A participação do enfermeiro na visita estava associada à maior realização de exame de mama (p=0,000), abdômen (p=0,000) e investigação de condições emocionais (p=0,029).Conclusões: Evidencia-se a necessidade de instituir um planejamento rotineiro para efetuar a visita domiciliar programática, priorizando as puérperas de risco.Palavras-chave: Período pós-parto. Visita domiciliar. Estratégia Saúde da Família. Saúde da mulher. Avaliação em saúde

    Effects of an Early Handling-Like Procedure and Individual Housing on Anxiety-Like Behavior in Adult C57BL/6J and DBA/2J Mice

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    Manipulations of rearing conditions have been used to examine the effects of early experience on adult behavior with varying results. Evidence suggests that postnatal days (PND) 15–21 are a time of particular susceptibility to environmental influences on anxiety-like behavior in mice. To examine this, we subjected C57BL/6J and DBA/2J mice to an early handling-like procedure. Pups were separated from dams from PND 12–20 for 30 minutes daily or received standard care. On PND 21, pups were weaned and either individually- or group- housed. On PND 60, anxiety-like behavior was examined on the elevated zero-maze. Although individually- housed animals took longer to enter an open quadrant of the maze, they spent more time in the open than group-housed animals. Additionally, we observed a trend of reduced anxiety-like behavior in C57BL/6J, but not DBA/2J mice that underwent the handling-like procedure

    Factors influencing sedentary behaviours after stroke:Findings from qualitative observations and interviews with stroke survivors and their caregivers

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    Background Stroke survivors are more sedentary than healthy, age-matched controls, independent of functional capacity. Interventions are needed to encourage a reduction in overall sedentary time, and regular breaks in prolonged periods of sedentary behaviour. This study captured the views and experiences of stroke survivors and their caregivers related to sedentary behaviour after stroke, to inform the development of an intervention to reduce sedentary behaviour. Methods Mixed-methods qualitative study. Non-participant observations were completed in two stroke services, inclusive of inpatient and community settings in the United Kingdom. Semi-structured interviews were conducted with stroke survivors and their caregivers (if available) at six- or nine-months post-stroke. Underpinned by the capability, opportunity and motivation (COM-B) model of behaviour change, observational data (132 h) were analysed thematically and interview data (n = 31 stroke survivors, n = 12 caregivers) were analysed using the Framework approach. Results Observation participants differed in functional ability whereas stroke survivor interviewees were all ambulant. Six themes related to sedentary behaviour after stroke were generated: (1) sedentary behaviour levels and patterns after stroke; (2) the physical and social environment in the stroke service and in the home; (3) standing and movement capability after stroke; (4) emotion and motivation after stroke; (5) caregivers’ influence on, and role in influencing stroke survivors’ sedentary behaviour; and (6) intervening to reduce sedentary behaviour after stroke. Capability, opportunity and motivation were influenced by the impact of the stroke and caregivers’ inclination to support sedentary behaviour reduction. Stroke survivors reported being more sedentary than they were pre-stroke due to impaired balance and co-ordination, increased fatigue, and reduced confidence in mobilising. Caregivers inclination to support stroke survivors to reduce sedentary behaviour depended on factors including their willingness to withdraw from the caregiver role, and their perception of whether the stroke survivor would act on their encouragement. Conclusions Many stroke survivors indicate being open to reducing sedentary behaviour, with appropriate support from stroke service staff and caregivers. The findings from this study have contributed to an intervention development process using the Behaviour Change Wheel (BCW) approach to develop strategies to reduce sedentary behaviour after stroke

    Adenyl cyclases and cAMP in plant signaling - past and present

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    In lower eukaryotes and animals 3'-5'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins

    Settling into an Increasingly Hostile World: The Rapidly Closing “Recruitment Window” for Corals

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    Free space is necessary for larval recruitment in all marine benthic communities. Settling corals, with limited energy to invest in competitive interactions, are particularly vulnerable during settlement into well-developed coral reef communities. This situation may be exacerbated for corals settling into coral-depauperate reefs where succession in nursery microhabitats moves rapidly toward heterotrophic organisms inhospitable to settling corals. To study effects of benthic organisms (at millimeter to centimeter scales) on newly settled corals and their survivorship we deployed terra-cotta coral settlement plates at 10 m depth on the Mesoamerican Barrier Reef in Belize and monitored them for 38 mo. During the second and third years, annual recruitment rates declined by over 50% from the previous year. Invertebrate crusts (primarily sponges) were absent at the start of the experiment but increased in abundance annually from 39, 60, to 73% of the plate undersides by year three. Subsequently, substrates hospitable to coral recruitment, including crustose coralline algae, biofilmed terra-cotta and polychaete tubes, declined. With succession, substrates upon which spat settled shifted toward organisms inimical to survivorship. Over 50% of spat mortality was due to overgrowth by sponges alone. This result suggests that when a disturbance creates primary substrate a “recruitment window” for settling corals exists from approximately 9 to 14 mo following the disturbance. During the window, early-succession, facilitating species are most abundant. The window closes as organisms hostile to coral settlement and survivorship overgrow nursery microhabitats
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