828 research outputs found

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    Liberal Foundations of Democratic Authority

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    In Democratic Authority, David Estlund argues that decision-procedures are to be judged solely by their tendency to generate morally superior decisions, but that because any relationship of authority must be acceptable to all qualified moral points of view, the epistemic benefits of less equal procedures must be evident beyond qualified objection. If all doctrines involved in political justification must be qualifiedly acceptable, however, the qualified acceptability requirement must itself be acceptable to qualified points of view. This article provides reasons for doubting that this ‘insularity’ can be achieved, and explores ways of reformulating the principle so that it does not exclude itself

    Classification of Marine Vessels in a Littoral Environment Using a Novel Training Database

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    Research into object classification has led to the creation of hundreds of databases for use as training sets in object classification algorithms. Datasets made up of thousands of cars, people, boats, faces and everyday objects exist for general classification techniques. However, no commercially available database exists for use with detailed classification and categorization of marine vessels commonly found in littoral environments. This research seeks to fill this void and is the combination of a multi-stage research endeavor designed to provide the missing marine vessel ontology. The first of the two stages performed to date introduces a novel training database called the Lister Littoral Database 900 (LLD-900) made up of over 900 high-quality images. These images consist of high-resolution color photos of marine vessels in working, active conditions taken directly from the field and edited for best possible use. Segmentation masks of each boat have been developed to separate the image into foreground and background sections. Segmentation masks that include boat wakes as part of the foreground section are the final image type included. These are included to allow for wake affordance detection algorithms rely on the small changes found in wakes made by different moving vessels. Each of these three types of images are split into their respective general classification folders, which consist of a differing number of boat categories dependent on the research stage. In the first stage of research, the initial database is tested using a simple, readily available classification algorithm known as the Nearest Neighbor Classifier. The accuracy of the database as a training set is tested and recorded and potential improvements are documented. The second stage incorporates these identified improvements and reconfigures the database before retesting the modifications using the same Nearest Neighbor Classifier along with two new methods known as the K-Nearest Neighbor Classifier and the Min-Mean Distance Classifier. These additional algorithms are also readily available and offer basic classification testing using different classification techniques. Improvements in accuracy are calculated and recorded. Finally, further improvements for a possible third iteration are discussed. The goal of this research is to establish the basis for a training database to be used with classification algorithms to increase the security of ports, harbors, shipping channels and bays. The purpose of the database is to train existing and newly created algorithms to properly identify and classify all boats found in littoral areas so that anomalous behavior detection techniques can be applied to determine when a threat is present. This research represents the completion of the initial steps in accomplishing this goal delivering a novel framework for use with littoral area marine vessel classification. The completed work is divided and presented in two separate papers written specifically for submission to and publication at appropriate conferences. When fully integrated with computer vision techniques, the database methodology and ideas presented in this thesis research will help to provide a vital new level of security in the littoral areas around the world

    Sloan Letter Visual Acuity Charts and computer monitor pixilation

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    Purpose This research investigates how pixilation of computer monitors affects visual acuity measurement. Methods Stimuli were presented on a computer monitor as 8 lines of 5 Sloan letter optotypes in standard logarithmic progression format, ranging in size from -0.4 to 0.3 logMAR. Test distance was varied so that pixels on the monitor subtended different angles: 0.125, 0.200, 0.315, 0.50, 0.79, 1.25, 1.97 minutes of arc. Two pixel-sampling strategies were used: unfiltered sampling in which each pixel was rendered either black or white; or filtered sampling, in which pixel brightness was taken as the average letter brightness integrated across a pixel-sized aperture (i.e. grey-scale smoothing of letter edges). Binocular acuity was measured at each distance on 10 participants aged 19 to 38 years (mean 27.9 ± 7.0) using their best spectacle correction. Results Each observer’s logMAR acuity v log pixel size data was fitted with a broken line function, in which LogMAR acuity was described by a horizontal straight line below a critical pixel size (Pcrit) and by a linear relationship between acuity and pixel size above Pcrit. For small pixels sizes (below Pcrit), average asymptotic thresholds were a mean of -0.209 logMAR (SD 0.06) for the filtered letters, just slightly but significantly better than for the unfiltered letters with a mean -0.184 logMAR (SD 0.06) (t9 = 2.26, p = 0.050). Average Pcrit was significantly (p Conclusion For the purposes of visual acuity measurement, Sloan letters can be well rendered by relatively coarse sampling. Filtered letters (i.e. with grey-scale smoothed edges) can be rendered with much coarser (apparently sub-Nyquist) pixel sampling than unfiltered letters

    Screening for post-traumatic stress symptoms in looked after children

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    Purpose: Many children who are looked after by the state have experienced adverse and traumatic life circumstances prior to being removed from their biological parents. Previous research has highlighted that many of them experience barriers to accessing psychological therapies. The purpose of this paper is to investigate the feasibility of assessing post-traumatic stress disorder (PTSD)-like symptoms using a screening tool, and through this to determine the prevalence of PTSD-like symptoms in looked after children presenting with emotional and/or behavioural problems.   Design/methodology/approach: The Child Revised Impact of Events Scale (CRIES-8) was identified as a suitable screening tool for PTSD-like symptoms. This measure was piloted for three months, and the prevalence of PTSD-like symptoms amongst respondents ( n=27) was recorded.   Findings: Prevalence of PTSD-like symptoms was found to be high 75 per cent amongst respondents. The psychometric properties of the CRIES-8 were similar to those found in a previous study assessing PTSD following a single-incident trauma. Health care professionals reported finding the CRIES-8 to be a clinically useful measure.   Originality/value: Prevalence of PTSD-like symptoms may be high amongst looked after children, and the CRIES-8 appears to have good psychometric properties when used with this population. It is likely that this highly treatable condition is under-detected: thus, recommendations are made for clinical practice and further research

    Implications of sampling design and sample size for national carbon accounting systems

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    <p>Abstract</p> <p>Background</p> <p>Countries willing to adopt a REDD regime need to establish a national Measurement, Reporting and Verification (MRV) system that provides information on forest carbon stocks and carbon stock changes. Due to the extensive areas covered by forests the information is generally obtained by sample based surveys. Most operational sampling approaches utilize a combination of earth-observation data and in-situ field assessments as data sources.</p> <p>Results</p> <p>We compared the cost-efficiency of four different sampling design alternatives (simple random sampling, regression estimators, stratified sampling, 2-phase sampling with regression estimators) that have been proposed in the scope of REDD. Three of the design alternatives provide for a combination of in-situ and earth-observation data. Under different settings of remote sensing coverage, cost per field plot, cost of remote sensing imagery, correlation between attributes quantified in remote sensing and field data, as well as population variability and the percent standard error over total survey cost was calculated. The cost-efficiency of forest carbon stock assessments is driven by the sampling design chosen. Our results indicate that the cost of remote sensing imagery is decisive for the cost-efficiency of a sampling design. The variability of the sample population impairs cost-efficiency, but does not reverse the pattern of cost-efficiency of the individual design alternatives.</p> <p>Conclusions, brief summary and potential implications</p> <p>Our results clearly indicate that it is important to consider cost-efficiency in the development of forest carbon stock assessments and the selection of remote sensing techniques. The development of MRV-systems for REDD need to be based on a sound optimization process that compares different data sources and sampling designs with respect to their cost-efficiency. This helps to reduce the uncertainties related with the quantification of carbon stocks and to increase the financial benefits from adopting a REDD regime.</p

    Widespread effects of climate change on local plant diversity

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    Human activity has sent many measures of biodiversity into long-term decline, and there are suggestions that the sheer scale of this impact is sufficient to consider the modern era as a geological epoch of its own, known as “The Anthropocene”. However, recent meta-analyses show that local alpha diversity is often stable or slightly increasing. Here, we show that the local alpha diversity (species richness) of plants found in quadrats and transects has increased the most in cooler regions of the world that have experienced the highest absolute changes (i.e., changes in either direction) in climate. The greatest statistical support is for the effects of precipitation change. On average, alpha diversity declined slightly (−4.2% per decade) in the third of sites that experienced the lowest precipitation change but increased (+10.8% per decade) in the third of sites with the highest precipitation change. These results suggest that the “perturbation” of local communities during climatic transitions increases the average number of species, at least temporarily, an effect likely to remain important as climate change continues

    Reply to Le Roux et al.

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    Constraining the long-term evolution of the slip rate for a major extensional fault system in the central Aegean, Greece, using thermochronology

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    The brittle/ductile transition is a major rheologic boundary in the crust yet little is known about how or if rates of tectonic processes are influenced by this boundary. In this study we examine the slip history of the large-scale Naxos/Paros extensional fault system (NPEFS), Cyclades, Greece, by comparing published slip rates for the ductile crust with new thermochronological constraints on slip rates in the brittle regime. Based on apatite and zircon fission-track (AFT and ZFT) and (U–Th)/He dating we observe variable slip rates across the brittle/ductile transition on Naxos. ZFT and AFT ages range from 11.8 ± 0.8 to 9.7 ± 0.8 Ma and 11.2 ± 1.6 to 8.2 ± 1.2 Ma and (U–Th)/He zircon and apatite ages are between 10.4 ± 0.4 to 9.2 ± 0.3 Ma and 10.7 ± 1.0 to 8.9 ± 0.6 Ma, respectively. On Paros, ZFT and AFT ages range from 13.1 ± 1.4 Ma to 11.1 ± 1.0 Ma and 12.7 ± 2.8 Ma to 10.5 ± 2.0 Ma while the (U–Th)/He zircon ages are slightly younger between 8.3 ± 0.4 Ma and 9.8 ± 0.3 Ma. All ages consistently decrease northwards in the direction of hanging wall transport. Most of our new thermochronological results and associated thermal modeling more strongly support the scenario of an identical fault dip and a constant or slightly accelerating slip rate of 6–8 km Myr− 1 on the NPEFS across the brittle/ductile transition. Even the intrusion of a large granodiorite body into the narrowing fault zone at 12 Ma on Naxos does not seem to have affected the thermal structure of the area in a way that would significantly disturb the slip rate. The data also show that the NPEFS accomplished a minimum total offset of 50 km between 16 and 8 Ma

    Welfare conditionality, inequality and unemployed people with alternative values

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    Labour and Conservatives’ claims that welfare conditionality is ‘fair’ rely upon an empirically unsupported assumption that almost-equal opportunities can exist alongside starkly unequal outcomes. Fifty interviews examined in-depth a diverse sample’s values, views about work and welfare, and labour market choices. Respondents’ views on equality strongly influenced their views on conditionality and what they considered acceptable labour market behaviour. ‘Alternative’ unemployed respondents, who rejected politicians’ suggestions they ‘should work’, nevertheless favoured an equal society with work obligations and often undertook voluntary work. The article concludes that policymakers should be more sensitive to Jobseeker’s Allowance claimants’ diverse moralities and motivations
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