946 research outputs found

    Simple bounds for queues fed by Markovian sources: a tool for performance evaluation

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    ATM traffic is complex but only simple statistical models are amenable to mathematical analysis. We discuss a class of queuing models which is wide enough to provide models which can reflect the features of real traffic, but which is simple enough to be analytically tractable, and review the bounds on the queue-length distribution that have been obtained. We use them to obtain bounds on QoS parameters and to give approximations to the effective bandwidth of such sources. We present some numerical techniques for calculating the bounds efficiently and describe an implementation of them in a computer package which can serve as a tool for qualitative investigations of performance in queuing systems

    Amanita drummondii and A. quenda (Basidiomycota), two new species from Western Australia, and an expanded description of A. walpolei

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    Three species of Amanita Pers. are documented from Western Australia. Amanita drummondii E.M.Davison is described from the south-west region; it appears to be widespread but infrequent. Amanita quenda E.M.Davison is described from the Perth Metropolitan area. Amanita walpolei O.K.Mill. is redescribed to include additional collections, drawing attention to the presence of clamp connections in all tissues. A BLASTn search has shown that there are no exact matches of the nuclear ribosomal internal transcribed spacer (ITS) region of each species with those in GenBank

    A primary phosphorus-deficient skeletal phenotype in juvenile Atlantic salmon Salmo salar : the uncoupling of bone formation and mineralization

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    To understand the effect of low dietary phosphorus (P) intake on the vertebral column of Atlantic salmon Salmo salar, a primary P deficiency was induced in post-smolts. The dietary P provision was reduced by 50% for a period of 10 weeks under controlled conditions. The animal's skeleton was subsequently analysed by radiology, histological examination, histochemical detection of minerals in bones and scales and chemical mineral analysis. This is the first account of how a primary P deficiency affects the skeleton in S. salar at the cellular and at the micro-anatomical level. Animals that received the P-deficient diet displayed known signs of P deficiency including reduced growth and soft, pliable opercula. Bone and scale mineral content decreased by c. 50%. On radiographs, vertebral bodies appear small, undersized and with enlarged intervertebral spaces. Contrary to the X-ray-based diagnosis, the histological examination revealed that vertebral bodies had a regular size and regular internal bone structures; intervertebral spaces were not enlarged. Bone matrix formation was continuous and uninterrupted, albeit without traces of mineralization. Likewise, scale growth continues with regular annuli formation, but new scale matrix remains without minerals. The 10 week long experiment generated a homogeneous osteomalacia of vertebral bodies without apparent induction of skeletal malformations. The experiment shows that bone formation and bone mineralization are, to a large degree, independent processes in the fish examined. Therefore, a deficit in mineralization must not be the only cause of the alterations of the vertebral bone structure observed in farmed S. salar. It is discussed how the observed uncoupling of bone formation and mineralization helps to better diagnose, understand and prevent P deficiency-related malformations in farmed S. salar

    Alignment and preliminary outcomes of an ELT-size instrument to a very large telescope: LINC-NIRVANA at LBT

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    LINC-NIRVANA (LN) is a high resolution, near infrared imager that uses a multiple field-of-view, layer-oriented, multi-conjugate AO system, consisting of four multi-pyramid wavefront sensors (two for each arm of the Large Binocular Telescope, each conjugated to a different altitude). The system employs up to 40 star probes, looking at up to 20 natural guide stars simultaneously. Its final goal is to perform Fizeau interferometric imaging, thereby achieving ELT-like spatial resolution (22.8 m baseline resolution). For this reason, LN is also equipped with a fringe tracker, a beam combiner and a NIR science camera, for a total of more than 250 optical components and an overall size of approximately 6x4x4.5 meters. This paper describes the tradeoffs evaluated in order to achieve the alignment of the system to the telescope. We note that LN is comparable in size to planned ELT instrumentation. The impact of such alignment strategies will be compared and the selected procedure, where the LBT telescope is, in fact, aligned to the instrument, will be described. Furthermore, results coming from early night-time commissioning of the system will be presented.Comment: 8 pages, 6 pages, AO4ELT5 Proceedings, 201

    The relationship between cognitive functioning, age and employment in people with severe mental illnesses in an urban area in India: a longitudinal study.

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    Although there is substantial evidence of the association between cognitive impairment and work in people with severe mental illnesses (SMI) in developed countries, less is known about this relationship in developing countries such as India. Studies showing higher rates of employment in people with SMI in developing countries than developed ones raise the question of whether cognitive functioning is related to work status and characteristics of work (e.g., wages earned). We conducted a one-year follow-up study to investigate the relationship between employment and cognitive functioning, assessed with the Montreal Cognitive Assessment (MoCA), in 150 participants with SMI (92% schizophrenia) living in an urban area and receiving psychiatric outpatient treatment at a public hospital in India. The MoCA had good internal reliability and test-retest reliability over the one-year period. Better cognitive functioning was associated with younger age, shorter duration of illness, higher education, and male gender. Both younger and older participants with higher cognitive functioning at baseline were more likely to be employed at baseline and one year later. Work status at baseline and one year follow-up was consistently related to executive functions among younger participants, and to attention among older participants, suggesting changes over the course of illness in the importance of specific cognitive domains for achieving satisfactory work performance. The findings suggest that cognitive functioning is associated with employment in people with SMI in India. Attention to impaired cognitive functioning may be critical to improving employment outcomes in this population.Dudley Allen Sargent Research Fund; Boston UniversityPublished versio

    A randomized controlled trial of Goal Management Training for executive functioning in schizophrenia spectrum disorders or psychosis risk syndromes

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    Background Executive functioning is essential to daily life and severely impaired in schizophrenia and psychosis risk syndromes. Goal Management Training (GMT) is a theoretically founded, empirically supported, metacognitive strategy training program designed to improve executive functioning. Methods A randomized controlled parallel group trial compared GMT with treatment as usual among 81 participants (GMT, n = 39 versus Wait List Controls, n = 42) recruited from an early intervention for psychosis setting. Computer generated random allocation was performed by someone independent from the study team and raters post-intervention were unaware of allocation. The primary objective was to assess the impact of GMT administered in small groups for 5 weeks on executive functioning. The secondary objective was to explore the potential of the intervention in influencing daily life functioning and clinical symptoms. Results GMT improved self-reported executive functioning, measured with the Behavior Rating Inventory of Executive Function – Adult version (BRIEF-A), significantly more than treatment as usual. A linear mixed model for repeated measures, including all partial data according to the principle of intention to treat, showed a significant group x time interaction effect assessed immediately after intervention (post-test) and 6 months after intervention (follow-up), F = 8.40, p .005, r .37. Improvement occurred in both groups in objective executive functioning as measured by neuropsychological tests, functional capacity, daily life functioning and symptoms of psychosis rated by clinicians. Self-reported clinical symptoms measured with the Symptoms Check List (SCL-10) improved significantly more after GMT than after treatment as usual, F = 5.78, p .019, r .29. Two participants withdrew due to strenuous testing and one due to adverse effects. Conclusions GMT had clinically reliable and lasting effects on subjective executive function. The intervention is a valuable addition to available treatment with considerable gains at low cost. Trial registration Registered at clinicaltrials.gov NCT03048695 09/02/2017.publishedVersio

    Donepezil Effects on Mood in Patients with Schizophrenia and Schizoaffective Disorder

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    Donepezil, 5 mg/d for 6 wk then 10 mg/d for 6 wk, and placebo daily for 12 wk in a double-blind cross-over paradigm, was added to the therapeutic regimen of 13 patients with schizophrenia or schizoaffective disorders, clinically stable on atypical antipsychotic medications. Patients had varying degrees of depressive symptoms, ranging from no depression to clinically significant depression. There was no worsening or induction of depression in individual patients or the group as a whole. In addition there was a statistically significant antidepressant effect in the group as a whole during the donepezil condition and a clinically significant antidepressant effect in the patients with clinically significant depressive symptoms, although there were not enough depressed patients in the group to conclude that donepezil may have antidepressant effects. Thus, in this study, donepezil did not induce or worsen depressive symptoms in schizophrenic and schizoaffective disorder patients

    Cognitive and social functioning correlates of employment among people with severe mental illness

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    We assess how social and cognitive functioning is associated to gaining employment for 213 people diagnosed with severe mental illness taking part in employment programs in Andalusia (Spain). We used the Repeatable Battery for the Assessment of Neuropsychological Status and the Social Functioning Scale and conducted two binary logistical regression analyses. Response variables were: having a job or not, in ordinary companies (OCs) and social enterprises (SEs), and working in and OC or not. There were two variables with significant adjusted odds ratios for having a job: “attention” and “Educational level”. There were five variables with significant odds ratios for having a job in an OC: “Sex”, “Educational level”, “Attention”, “Communication”, and “Independence-competence”. The study looks at the possible benefits of combining employment with support and social enterprises in employment programs for these people and underlines how both social and cognitive functioning are central to developing employment models
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