311 research outputs found

    A comparison of oceanic skin effect parameterisations using ship borne radiometer data

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    Sea surface temperature data from a shipborne radiometer were used to assess the thermal skin effect parameterization schemes of Saunders [1967], Hasse [1971], Schlüssel et al. [1990], and Soloviev and Schlüssel [1994]. Under low-wind, high-insolation conditions, the presence of a near surface thermocline resulted in an apparent skin effect which depended on the history of the surface heating. Neglecting these cases, the Saunders [1967] and other schemes which omit solar radiation were the most effective. The observed variation with wind speed of the adjustable coefficient, λ s , in the Saunders formulae was similar to that predicted by Soloviev and Schlüssel [1994], but the values were significantly higher, resulting in a greater magnitude of the observed skin effect. For the conditions occurring in this data set the better formulae predicted the skin effect with a standard deviation of ±0.16° C compared to a variation of the observed skin effect of nearly ±0.3°C

    Mindfulness-based exposure and response prevention for obsessive compulsive disorder: study protocol for a pilot randomised controlled trial

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    Background Obsessive Compulsive Disorder (OCD) is a distressing and debilitating condition affecting 1-2% of the population. Exposure and response prevention (ERP) is a behaviour therapy for OCD with the strongest evidence for effectiveness of any psychological therapy for the condition. Even so, only about half of people offered ERP show recovery after the therapy. An important reason for ERP failure is that about 25% of people drop out early, and even for those who continue with the therapy, many do not regularly engage in ERP tasks, an essential element of ERP. A mindfulness-based approach has the potential to reduce drop-out from ERP and to improve ERP task engagement with an emphasis on accepting difficult thoughts, feelings and bodily sessions and on becoming more aware of urges, rather than automatically acting on them. Methods/Design This is a pilot randomised controlled trial of mindfulness-based ERP (MB-ERP) with the aim of establishing parameters for a definitive trial. Forty participants diagnosed with OCD will be allocated at random to a 10-session ERP group or to a 10-session MB-ERP group. Primary outcomes are OCD symptom severity and therapy engagement. Secondary outcomes are depressive symptom severity, wellbeing and obsessive-compulsive beliefs. A semi-structured interview with participants will guide understanding of change processes. Discussion Findings from this pilot study will inform future research in this area, and if effect sizes on primary outcomes are in favour of MB-ERP in comparison to ERP, funding for a definitive trial will be sought

    Comparative susceptibility of mosquito populations in North Queensland, Australia to oral infection with dengue virus.

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    Dengue is the most prevalent arthropod-borne virus, with at least 40% of the world's population at risk of infection each year. In Australia, dengue is not endemic, but viremic travelers trigger outbreaks involving hundreds of cases. We compared the susceptibility of Aedes aegypti mosquitoes from two geographically isolated populations to two strains of dengue virus serotype 2. We found, interestingly, that mosquitoes from a city with no history of dengue were more susceptible to virus than mosquitoes from an outbreak-prone region, particularly with respect to one dengue strain. These findings suggest recent evolution of population-based differences in vector competence or different historical origins. Future genomic comparisons of these populations could reveal the genetic basis of vector competence and the relative role of selection and stochastic processes in shaping their differences. Lastly, we show the novel finding of a correlation between midgut dengue titer and titer in tissues colonized after dissemination

    Comparing fishers\u27 and scientists\u27 estimates of size-at-maturity and maximum body size as indicators of overfishing

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    We tested whether fishers’ local ecological knowledge (LEK) of two fish life-history parameters, size at maturity (SAM) at maximum body size (MS), was comparable to scientific estimates (SEK) of the same parameters, and whether LEK influenced fishers’ perceptions of sustainability. Local ecological knowledge was documented for 82 fishers from a small-scale fishery in Samaná Bay, Dominican Republic, whereas SEK was compiled from the scientific literature. Size at maturity estimates derived from LEK and SEK overlapped for most of the 15 commonly harvested species (10 of 15). In contrast, fishers’ maximum size estimates were usually lower than (eight species), or overlapped with (five species) scientific estimates. Fishers’ size-based estimates of catch composition indicate greater potential for overfishing than estimates based on SEK. Fishers’ estimates of size at capture relative to size at maturity suggest routine inclusion of juveniles in the catch (9 of 15 species), and fishers’ estimates suggest that harvested fish are substantially smaller than maximum body size for most species (11 of 15 species). Scientific estimates also suggest that harvested fish are generally smaller than maximum body size (13 of 15), but suggest that the catch is dominated by adults for most species (9 of 15 species), and that juveniles are present in the catch for fewer species (6 of 15). Most Samaná fishers characterized the current state of their fishery as poor (73%) and as having changed for the worse over the past 20 yr (60%). Fishers stated that concern about overfishing, catching small fish, and catching immature fish contributed to these perceptions, indicating a possible influence of catch-size composition on their perceptions. Future work should test this link more explicitly because we found no evidence that the minority of fishers with more positive perceptions of their fishery reported systematically different estimates of catch-size composition than those with the more negative majority view. Although fishers’ and scientific estimates of size at maturity and maximum size parameters sometimes differed, the fact that fishers make routine quantitative assessments of maturity and body size suggests potential for future collaborative monitoring efforts to generate estimates usable by scientists and meaningful to fishers

    Comparing monitoring data collected by volunteers and professionals shows that citizen scientists can detect long-term change on coral reefs

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    Citizen science is increasing and can complement the work of professional scientists, but the value of citizen data is often untested. We therefore compared the long-term changes to coral reefs that were detected by a professional and volunteer monitoring program, operated by University of Rhode Island (URI) staff and Reef Check volunteers, respectively. Both groups monitored reefs in the British Virgin Islands from 1997 to 2012 but mostly monitored different sites (URI 8 sites and Reef Check 4 sites). When URI staff visited the Reef Check sites to perform a side-by-side to comparison, Reef Check fish density estimates were consistently higher than those made by URI observers but benthic indicators showed better agreement. When long-term trends were compared, the two programs detected qualitatively similar trends in the % cover of live coral and coral rubble, but temporal changes in the cover of other benthic indicators were less consistent. The URI program detected a widespread increase in parrotfish densities and a decline in snappers, whereas the Reef Check surveys detected no consistent changes in any fish density indicators. Overall, site-specific temporal trends revealed by the URI program were more often statistically significant than those from Reef Check (twice as often for benthic taxa, and five times as often for fish taxa), which implies greater precision of the scientists’ counts. Nonetheless, volunteers were able to detect important changes in benthic communities and so have a valuable role to play in assessing change on coral reefs

    Risk reduction in general practice and the role of the receptionist

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    Medical receptionists play a crucial and pivotal role in any practice, as they are usually the first points of contact for patients and the intermediaries through whom contacts with the medical practitioners are made. This paper reports the findings of a qualitative study of medical receptionists undertaken to explore their role in general practice, particularly in relation to activities involving direct patient assessment, monitoring, counselling and therapy. The findings highlight a number of significant issues in relation to the potential liability of the receptionists, the medical practitioners, the medical centre owners and their insurers

    The disconnect between knowledge and perceptions: A study of fishermen’s local ecological knowledge and their perception of the state of fisheries and how these are managed in the Dominican Republic

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    Understanding what fishers know about the ecology of the fish they catch, and how they perceive the state and management of their fisheries can guide efforts towards more sustainable fishing practices. We tested relationships between fishers’ local ecological knowledge (LEK) and their perceptions of their fisheries and of marine protected areas in the Dominican Republic. A qualitative-quantitative methodological sequence using data from interviews with 152 multi-species fishers revealed variable, but generally high levels of LEK, particularly of habitat use and predator–prey interactions. The majority reported negative perceptions of the state of their fishery and were aware of local management actions. Contrary to study expectations, we found that fishers’ LEK, measured by Cultural Consensus Analysis, did not significantly co-vary with their perceptions of the state of fisheries or with their awareness of, and support for, marine protected areas. These results highlight the need to identify and understand barriers to information flow and communication in local fisheries’ social/political networks

    The Forgotten Kingdom.: New investigations in the prehistory of Eswatini

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    The kingdom of Eswatini provides a rich archaeological sequence covering all time periods from the Early Stone Age to the Iron Age. For over 27 years though, no or very little archaeological research was conducted in the country. In the scope of a new project funded by the German Research Foundation (DFG) we aim to re-excavate and re-date Lion Cavern, the potentially oldest ochre mine in the world. In addition, we conduct a largescale geological survey for outcrops of ochre and test their geochemical signatures for comparative studies with archaeological ochre pieces from MSA and LSA assemblages in Eswatini. Here we present a review of the research history of the kingdom and some preliminary results from our ongoing project

    Optimistic Planning for Markov Decision Processes

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    International audienceThe reinforcement learning community has recently intensified its interest in online planning methods, due to their relative independence on the state space size. However, tight near-optimality guarantees are not yet available for the general case of stochastic Markov decision processes and closed-loop, state-dependent planning policies. We therefore consider an algorithm related to AO* that optimistically explores a tree representation of the space of closed-loop policies, and we analyze the near-optimality of the action it returns after n tree node expansions. While this optimistic planning requires a finite number of actions and possible next states for each transition, its asymptotic performance does not depend directly on these numbers, but only on the subset of nodes that significantly impact near-optimal policies. We characterize this set by introducing a novel measure of problem complexity, called the near-optimality exponent. Specializing the exponent and performance bound for some interesting classes of MDPs illustrates the algorithm works better when there are fewer near-optimal policies and less uniform transition probabilities
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