953 research outputs found

    The effects of riparian forestry on invertebrate drift and brown trout in upland streams of contrasting acidity

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    International audienceVariations in macroinvertebrate drift and benthic invertebrate abundance were assessed in 30 upland Welsh streams of varying acidity (pH 6.0) and riparian land-use (conifer, moorland or native broadleaf). The consequences for the diet and condition of wild brown trout Salmo trutta were also assessed. As expected from previous studies, there were significant reductions in benthic invertebrate abundance, aquatic drift density (by >60%), aquatic drift biomass (by >35%), total drift density (by >35%) and total drift biomass (by >20%) at acid sites by comparison with circumneutral sites due largely to the scarcity of mayflies. Absolute drift from terrestrial sources was unrelated to stream pH but formed a significantly greater proportion of total drift at acid sites (30-65% of density) than at circumneutral sites (20-40%) as aquatic contributions declined. Most of this apparent land use effect reflected significantly increased terrestrial drift under broadleaves. There was no significant reduction in terrestrial or aquatic drift at conifer forest sites per se after accounting for low pH. Trout diet varied substantially between locations partly reflecting variations in drift: significantly fewer mayflies and stoneflies were eaten at acid sites, and significantly more terrestrial prey were eaten under broadleaves. However, acidity did not reduce trout condition or gut-fullness. Unexpectedly, trout condition was significantly enhanced at conifer sites, irrespective of their pH. Hence, acidity has greater effects on the benthic abundance and drift density of invertebrates in upland streams than does riparian land use. However, trout forage flexibly enough to offset any possible food deficit, for example by switching to chironomids and terrestrial invertebrates. Enhanced terrestrial contributions to invertebrate drift from riparian broadleaf trees may be important in supplementing foraging opportunities for trout where aquatic prey are scarce. These data illustrate the value of native tree species in riparian locations in upland Britain and the energy subsidy they provide might well be disproportionately important for otherwise impoverished acid streams Keywords: brown trout, land-use, acidification, drift, forestry, stream

    Analysing decision logs to understand decision-making in serious crime investigations

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    Objective: To study decision-making by detectives when investigating serious crime through the examination of Decision Logs to explore hypothesis generation and evidence selection. Background: Decision logs are used to record and justify decisions made during serious crime investigations. The complexity of investigative decision-making is well documented, as are the errors associated with miscarriages of justice and inquests. The use of decision logs has not been the subject of an empirical investigation, yet they offer an important window into the nature of investigative decision-making in dynamic, time-critical environments. Method: A sample of decision logs from British police forces was analyzed qualitatively and quantitatively to explore hypothesis generation and evidence selection by police detectives. Results: Analyses revealed diversity in documentation of decisions that did not correlate with case type, and identified significant limitations of the decision log approach to supporting investigative decision-making. Differences emerged between experienced and less experienced officers’ decision log records in exploration of alternative hypotheses, generation of hypotheses, and sources of evidential enquiry opened over phase of investigation. Conclusion: The practical use of decision logs is highly constrained by their format and context of use. Despite this, decision log records suggest that experienced detectives display strategic decision-making to avoid confirmation and satisficing that affect less experienced detectives. Application: Potential applications of this research include both training in case documentation and the development of new decision log media that encourage detectives, irrespective of experience, to generate multiple hypotheses and optimize the timely selection of evidence to test them

    The statistical laws of popularity: Universal properties of the box office dynamics of motion pictures

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    Are there general principles governing the process by which certain products or ideas become popular relative to other (often qualitatively similar) competitors? To investigate this question in detail, we have focused on the popularity of movies as measured by their box-office income. We observe that the log-normal distribution describes well the tail (corresponding to the most successful movies) of the empirical distributions for the total income, the income on the opening week, as well as, the weekly income per theater. This observation suggests that popularity may be the outcome of a linear multiplicative stochastic process. In addition, the distributions of the total income and the opening income show a bimodal form, with the majority of movies either performing very well or very poorly in theaters. We also observe that the gross income per theater for a movie at any point during its lifetime is, on average, inversely proportional to the period that has elapsed after its release. We argue that (i) the log-normal nature of the tail, (ii) the bimodal form of the overall gross income distribution, and (iii) the decay of gross income per theater with time as a power law, constitute the fundamental set of {\em stylized facts} (i.e., empirical "laws") that can be used to explain other observations about movie popularity. We show that, in conjunction with an assumption of a fixed lower cut-off for income per theater below which a movie is withdrawn from a cinema, these laws can be used to derive a Weibull distribution for the survival probability of movies which agrees with empirical data. The connection to extreme-value distributions suggests that popularity can be viewed as a process where a product becomes popular by avoiding failure (i.e., being pulled out from circulation) for many successive time periods. We suggest that these results may apply to popularity in general.Comment: 14 pages, 11 figure

    Interventions for hidradenitis suppurativa: a Cochrane systematic review incorporating GRADE assessment of evidence quality

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    Background More than 50 interventions have been used to treat hidradenitis suppurativa (HS) and so therapy decisions can be challenging. Objectives To summarise and appraise randomised controlled trial (RCT) evidence for HS interventions in adults. Materials and methods Searches were conducted in MEDLINE, EMBASE, CENTRAL, LILACS, five trials registers and abstracts from eight dermatology conferences until 13 August 2015. Two review authors independently assessed study eligibility, extracted data and assessed methodological quality. Primary outcomes were quality of life and adverse effects of the interventions. Results Twelve trials, from 1983 to 2015, investigating 15 different interventions met our inclusion criteria. Median trial duration was 16 weeks and the median number of participants was 27. Adalimumab 40mg weekly improved the Dermatology Life Quality Index by 4.0 points, which equates to the minimal clinically important difference for the scale, compared to placebo (95% confidence interval (CI) -6.5 to -1.5 points). Evidence quality was reduced to ‘moderate’ because results are based on only a single study. Adalimumab 40mg every other week was ineffective in a meta-analysis of two studies comprising 124 participants. Infliximab 5mg/kg improved DLQI score by 8.4 points after eight weeks in a moderate quality study completed by 33 of 38 participants. Etanercept 50mg twice weekly was ineffective. Inclusion of a gentamicin sponge prior to primary closure did not improve outcomes. Other interventions including topical and oral antibiotics, were investigated by relatively small studies, preventing treatment recommendations due to imprecision. Conclusions More, larger RCTs are required to investigate most HS interventions, particularly oral treatments and surgical therapy. Moderate quality evidence suggests that adalimumab given weekly and infliximab are effective whereas adalimumab every other week is ineffective

    Drawing the answers: Sketching to support free and probed recall by child witnesses and victims with autism spectrum disorder

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    The success of witness interviews in the criminal justice system depends on the accuracy of information obtained, which is a function of both amount and quality of information. Attempts to enhance witness retrieval such as mental reinstatement of context have been designed with typically developed adults in mind. In this paper, the relative benefits of mental and sketch reinstatement mnemonics are explored with both typically developing children and children with autism. Children watched a crime event video, and their retrieval of event information was examined in free and probed recall phases of a cognitive interview. As expected, typically developing children recalled more correct information of all types than children with autism during free and probed recall phases. Sketching during free recall was more beneficial for both groups in both phases in reducing the amount of incorrect items, but the relative effect of sketching on enhancing retrieval accuracy was greater for children with autism. The results indicate the benefits of choosing retrieval mnemonics that are sensitive to the specific impairments of autistic individuals, and suggest that retrieval accuracy during interviews can be enhanced, in some cases to the same level as that of typically developing individuals

    Comparison of the two most commonly used treatments for pyoderma gangrenosum: results of the STOP GAP randomised controlled trial

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    Objective To determine whether ciclosporin is superior to prednisolone for the treatment of pyoderma gangrenosum, a painful, ulcerating skin disease with a poor evidence base for management. Design Multicentre, parallel group, observer blind, randomised controlled trial. Setting 39 UK hospitals, recruiting from June 2009 to November 2012. Participants 121 patients (73 women, mean age 54 years) with clinician diagnosed pyoderma gangrenosum. Clinical diagnosis was revised in nine participants after randomisation, leaving 112 participants in the analysis set (59 ciclosporin; 53 rednisolone). Intervention Oral prednisolone 0.75 mg/kg/day compared with ciclosporin 4 mg/kg/day, to a maximum dose of 75 and 400 mg/day, respectively. Main outcome measures The primary outcome was speed of healing over six weeks, captured using digital images and assessed by blinded investigators. Secondary outcomes were time to healing, global treatment response, resolution of inflammation, self reported pain, quality of life, number of treatment failures, adverse reactions, and time to recurrence. Outcomes were assessed at baseline and six weeks and when the ulcer had healed (to a maximum of six months). Results Of the 112 participants, 108 had complete primary outcome data at baseline and six weeks (57 ciclosporin; 51 rednisolone). Groups were balanced at baseline. The mean (SD) speed of healing at six weeks was −0.21 (1.00) cm2/day in the ciclosporin group compared with −0.14 (0.42) cm2/day in the prednisolone group. The adjusted mean difference showed no between group difference (0.003 cm2/day, 95% confidence interval −0.20 to 0.21; P=0.97). By six months, ulcers had healed in 28/59 (47%) participants in the ciclosporin group compared with 25/53 (47%) in the prednisolone group. In those with healed ulcers, eight (30%) receiving ciclosporin and seven (28%) receiving prednisolone had a recurrence. Adverse reactions were similar for the two groups (68% ciclosporin and 66% prednisolone), but serious adverse reactions, especially infections, were more common in the prednisolone group. Conclusion Prednisolone and ciclosporin did not differ across a range of objective and patient reported outcomes. Treatment decisions for individual patients may be guided by the different side effect profiles of the two drugs and patient preference. Trial registration Current Controlled Trials ISRCTN35898459

    Corporate governance and financial constraints on strategic turnarounds

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    The paper extends the Robbins and Pearce (1992) two-stage turnaround response model to include governance factors. In addition to the retrenchment and recovery, the paper proposes the addition of a realignment stage, referring specifically to the re-alignment of expectations of principal and agent groups. The realignment stage imposes a threshold that must be crossed before the retrenchment and hence recovery stage can be entered. Crossing this threshold is problematic to the extent that the interests of governance-stakeholder groups diverge in a crisis situation. The severity of the crisis impacts on the bases of strategy contingent asset valuation leading to the fragmentation of stakeholder interests. In some cases the consequence may be that management are prevented from carrying out turnarounds by governance constraints. The paper uses a case study to illustrate these dynamics, and like the Robbins and Pearce study, it focuses on the textile industry. A longitudinal approach is used to show the impact of the removal of governance constraints. The empirical evidence suggests that such financial constraints become less serious to the extent that there is a functioning market for corporate control. Building on governance research and turnaround literature, the paper also outlines the general case necessary and sufficient conditions for successful turnarounds

    Global Systems Science and Policy

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    The vision of Global Systems Science (GSS) is to provide scientific evidence and means to engage into a reflective dialogue to support policy-making and public action and to enable civil society to collectively engage in societal action in response to global challenges like climate change, urbanisation, or social inclusion. GSS has four elements: policy and its implementation, the science of complex systems, policy informatics, and citizen engagement. It aims to give policy makers and citizens a better understanding of the possible behaviours of complex social systems. Policy informatics helps generate and evaluate policy options with computer-based tools and the abundance of data available today. The results they generate are made accessible to everybody—policymakers, citizens—through intuitive user interfaces, animations, visual analytics, gaming, social media, and so on. Examples of Global Systems include epidemics, finance, cities, the Internet, trade systems and more. GSS addresses the question of policies having desirable outcomes, not necessarily optimal outcomes. The underpinning idea of GSS is not to precisely predict but to establish possible and desirable futures and their likelihood. Solving policy problems is a process, often needing the requirements, constraints, and lines of action to be revisited and modified, until the problem is ‘satisficed’, i.e. an acceptable compromise is found between competing objectives and constraints. Thus policy problems and their solutions coevolve much as in a design process. Policy and societal action is as much about attempts to understand objective facts as it is about the narratives that guide our actions. GSS tries to reconcile these apparently contradictory modes of operations. GSS thus provides policy makers and society guidance on their course of action rather than proposing (illusionary) optimal solutions
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