473 research outputs found

    On the homomorphism order of labeled posets

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    Partially ordered sets labeled with k labels (k-posets) and their homomorphisms are examined. We give a representation of directed graphs by k-posets; this provides a new proof of the universality of the homomorphism order of k-posets. This universal order is a distributive lattice. We investigate some other properties, namely the infinite distributivity, the computation of infinite suprema and infima, and the complexity of certain decision problems involving the homomorphism order of k-posets. Sublattices are also examined.Comment: 14 page

    On the ability of spectroscopic SZ effect measurements to determine the temperature structure of galaxy clusters

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    (abridged) We explore in this paper the ability of spatially resolved spectroscopic measurements of the SZ effect (SZE) to determine the temperature profile of galaxy clusters. We derive a general formalism for the thermal SZE in galaxy clusters with a non-uniform temperature profile that can be applied to both cool-core clusters and non-cool core cluster with an isothermal or non-isothermal temperature structure. We derive an inversion technique through which the electron distribution function can be extracted from spectroscopic SZE observations over a wide frequency range. We study the fitting procedure to extract the cluster temperature from a set of simulated spatially resolved spectroscopic SZE observations in different bands of the spectrum, from 100 to 450 GHz. The results of our analysis for three different cluster prototypes (A2199 with a low-temperature cool core, Perseus with a relatively high-temperature cool core, Ophiuchus with an isothermal temperature distribution) provide both the required precision of the SZE observations and the optimal frequency bands for a determination of the cluster temperature similar or better than that obtainable from X-ray observations. The precision of SZE-derived temperature is also discussed for the outer regions of clusters. We also study the possibility to extract, from our method, the parameters characterizing the non-thermal SZE spectrum of the relativistic plasma contained in the lobes of radio galaxies as well as the spectrum of relativistic electrons co-spatially distributed with the thermal plasma in clusters with non-thermal phenomena. We find that the next generation SZE experiments with spectroscopic capabilities can provide precise temperature distribution measurements (...)Comment: Submitted to Astronomy & Astrophysic

    Evaluating Retinal Function in Age-Related Maculopathy with the ERG Photostress Test

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    PURPOSE. To evaluate the diagnostic potential of the electroretinogram (ERG) photostress test and the focal cone ERG in age-related maculopathy (ARM). METHODS. The cohort comprised 31 patients with ARM and 27 age-matched control subjects. The ERG photostress test was used to monitor cone adaptation after intense light adaptation. Focal 41- and 5-Hz cone ERGs were recorded monocularly (central 20°) to assess steady state retinal function. Univariate analysis identified electrophysiological parameters that differed between groups, and receiver operating characteristic (ROC) curves were constructed to assess their diagnostic potential. Logistic regression analysis determined the diagnostic potential of a model incorporating several independent predictors of ARM. RESULTS. The rate of recovery of the ERG photostress test was reduced (recovery was slower) in subjects with ARM. The parameter exhibited good diagnostic potential (P = 0.002, area under ROC curve = 0.74). The implicit times of the 5-Hz (a-wave, P = 0.002; b-wave, P < 0.001) and the 41-Hz (P < 0.001) focal cone ERGs were increased, and the 41-Hz focal cone ERG amplitude (P = 0.003) and focal to full-field amplitude ratio (P = 0.001) were reduced in the ARM group. Logistic regression analysis identified three independent predictors of ARM, including the rate of recovery of the ERG photostress test. CONCLUSIONS. Early ARM has a marked effect on the kinetics of cone adaptation. The clinical application of the ERG photostress test increases the sensitivity and specificity of a model for the diagnosis of ARM. Improved assessment of the functional integrity of the central retina will facilitate early diagnosis and evaluation of therapeutic interventions

    Comparing cost-effectiveness of surface water flood management interventions in a UK catchment

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    This is the final published version. Available from Wiley via the DOI in this record.Despite significant consequences caused by recent events, surface water flooding has historically been of lower priority relative to fluvial and coastal risks in UK flood management. Legislation and research proposes a variety of innovative interventions to address this; however, widespread application of these remains a challenge due to a number of institutional, economic, and technical barriers. This research applies a framework capable of fast and high-resolution assessment of intervention cost-effectiveness as an opportunity to improve available evidence and encourage uptake of interventions through analysing permutations of type, scale, and distribution in urban catchments. Fast assessment of many scenarios is achieved using a cellular automata flood model and a simplified representation of interventions. Conventional and green strategies are examined across a range of design standard and high-magnitude rainfall events in an urban catchment. Results indicate high-volume rainwater capture interventions demonstrate a significant reduction in estimated annual damage costs, and localised surface water drainage interventions exhibit high cost-effectiveness for damage reduction. Analysis of performance across a wide range of return periods enhances available evidence for option comparison decision support and provides a basis for future resilience assessment of interventions.Engineering and Physical Sciences Research Council (EPSRC

    4-Deoxy-4-fluoro-GalNAz (4FGalNAz) is a metabolic chemical reporter of O-GlcNAc modifications, highlighting the notable substrate flexibility of O-GlcNAc transferase

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    Bio-orthogonal chemistries have revolutionized many fields. For example, metabolic chemical reporters (MCRs) of glycosylation are analogues of monosaccharides that contain a bio-orthogonal functionality, such as azides or alkynes. MCRs are metabolically incorporated into glycoproteins by living systems, and bio-orthogonal reactions can be subsequently employed to install visualization and enrichment tags. Unfortunately, most MCRs are not selective for one class of glycosylation (e.g., N-linked vs O-linked), complicating the types of information that can be gleaned. We and others have successfully created MCRs that are selective for intracellular O-GlcNAc modification by altering the structure of the MCR and thus biasing it to certain metabolic pathways and/or O-GlcNAc transferase (OGT). Here, we attempt to do the same for the core GalNAc residue of mucin O-linked glycosylation. The most widely applied MCR for mucin O-linked glycosylation, GalNAz, can be enzymatically epimerized at the 4-hydroxyl to give GlcNAz. This results in a mixture of cell-surface and O-GlcNAc labeling. We reasoned that replacing the 4-hydroxyl of GalNAz with a fluorine would lock the stereochemistry of this position in place, causing the MCR to be more selective. After synthesis, we found that 4FGalNAz labels a variety of proteins in mammalian cells and does not perturb endogenous glycosylation pathways unlike 4FGalNAc. However, through subsequent proteomic and biochemical characterization, we found that 4FGalNAz does not widely label cell-surface glycoproteins but instead is primarily a substrate for OGT. Although these results are somewhat unexpected, they once again highlight the large substrate flexibility of OGT, with interesting and important implications for intracellular protein modification by a potential range of abiotic and native monosaccharides

    Liquid-gas phase transition in nuclear multifragmentation

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    The equation of state of nuclear matter suggests that at suitable beam energies the disassembling hot system formed in heavy ion collisions will pass through a liquid-gas coexistence region. Searching for the signatures of the phase transition has been a very important focal point of experimental endeavours in heavy ion collisions, in the last fifteen years. Simultaneously theoretical models have been developed to provide information about the equation of state and reaction mechanisms consistent with the experimental observables. This article is a review of this endeavour.Comment: 63 pages, 27 figures, submitted to Adv. Nucl. Phys. Some typos corrected, minor text change

    'Time Out' for Women: Innovation in Scotland in a Context of Change

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    The 218 Centre was set up following consistent concerns about the increasing number of women in prison in Scotland and the high-level needs of many of these women. It is an innovative and high profile attempt to develop appropriate responses to women in the criminal justice system. It offers women an opportunity for ‘time out’ of their normal environment without resorting to ‘time in’ custody, providing both residential and community-based services. This article outlines some of the issues and challenges which characterised the early development and operation of the 218 Centre. It illustrates the ways in which some of the issues that arose during the evaluation resonate with current and ongoing debates within criminology and draws attention to the difficulties in using the criminal justice system to address other issues

    Impaired contractile function of the supraspinatus in the acute period following a rotator cuff tear

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    Background: Rotator cuff (RTC) tears are a common clinical problem resulting in adverse changes to the muscle, but there is limited information comparing histopathology to contractile function. This study assessed supraspinatus force and susceptibility to injury in the rat model of RTC tear, and compared these functional changes to histopathology of the muscle. Methods: Unilateral RTC tears were induced in male rats via tenotomy of the supraspinatus and infraspinatus. Maximal tetanic force and susceptibility to injury of the supraspinatus muscle were measured in vivo at day 2 and day 15 after tenotomy. Supraspinatus muscles were weighed and harvested for histologic analysis of the neuromuscular junction (NMJ), intramuscular lipid, and collagen. Results: Tenotomy resulted in eventual atrophy and weakness. Despite no loss in muscle mass at day 2 there was a 30% reduction in contractile force, and a decrease in NMJ continuity and size. Reduced force persisted at day 15, a time point when muscle atrophy was evident but NMJ morphology was restored. At day 15, torn muscles had decreased collagen-packing density and were also more susceptible to contraction-induced injury. Conclusion: Muscle size and histopathology are not direct indicators of overall RTC contractile health. Changes in NMJ morphology and collagen organization were associated with changes in contractile function and thus may play a role in response to injury. Although our findings are limited to the acute phase after a RTC tear, the most salient finding is that RTC tenotomy results in increased susceptibility to injury of the supraspinatus

    Self-reported health status and access to health services in a sample of prisoners in Italy

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    <p>Abstract</p> <p>Background</p> <p>Self-reported health status in underserved population of prisoners has not been extensively explored. The purposes of this cross-sectional study were to assess self-reported health, quality of life, and access to health services in a sample of male prisoners of Italy.</p> <p>Methods</p> <p>A total of 908 prisoners received a self-administered anonymous questionnaire pertaining on demographic and detention characteristics, self-reported health status and quality of life, access to health services, lifestyles, and participation to preventive, social, and rehabilitation programs. A total of 650 prisoners agreed to participate in the study and returned the questionnaire.</p> <p>Results</p> <p>Respectively, 31.6% and 43.5% of prisoners reported a poor perceived health status and a poor quality of life, and 60% admitted that their health was worsened or greatly worsened during the prison stay. Older age, lower education, psychiatric disorders, self-reported health problems on prison entry, and suicide attempts within prison were significantly associated with a perceived worse health status. At the time of the questionnaire delivery, 30% of the prisoners self-reported a health problem present on prison entry and 82% present at the time of the survey. Most frequently reported health problems included dental health problems, arthritis or joint pain, eye problems, gastrointestinal diseases, emotional problems, and high blood pressure. On average, prisoners encountered general practitioners six times during the previous year, and the frequency of medical encounters was significantly associated with older age, sentenced prisoners, psychiatric disorders, and self-reported health problems on prison entry.</p> <p>Conclusions</p> <p>The findings suggest that prisoners have a perceived poor health status, specific care needs and health promotion programs are seldom offered. Programs for correction of risk behaviour and prevention of long-term effects of incarceration on prisoners' health are strongly needed.</p

    Sentencing drug offenders under the 2003 Criminal Justice Act: Challenges for the probation service

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    For the most part the 2003 Criminal Justice Act, which came into effect in England and Wales in April 2005, was accepted by the probation service with relatively little opposition. Given the enormity of its impact acquiescence to this degree of change ought to come as something of a surprise. The 2003 Act changed fundamentally the nature of community supervision, it brought to an end the traditional range of non-custodial penalties and replaced them with a single community order to which sentencers could add any of 12 possible requirements. This paper considers the impact of the 2003 legislation on one particular offender group - drug misusers. Drug misusing offenders have the potential to pose serious difficulties for probation officers; the habitual nature of drug addiction and a tendency toward an irregular lifestyle make drug misusers particularly susceptible to breach. Under the new legislation courts have significantly fewer options available to them when responding to incidents of offender non-compliance. This paper argues that many of the provisions of the 2003 Act together with developments elsewhere in the UK are likely to have impacted disproportionately on those groups whose lifestyles are chaotic and whose routines are incompatible with the terms and conditions of modern day probation practice. It concludes that greater flexibility towards non-compliance, supported by regular and consistent judicial review, would encourage improved rates of compliance and retention in treatment and improved outcomes for offenders
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