1,947 research outputs found

    Dependence Logic with Generalized Quantifiers: Axiomatizations

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    We prove two completeness results, one for the extension of dependence logic by a monotone generalized quantifier Q with weak interpretation, weak in the meaning that the interpretation of Q varies with the structures. The second result considers the extension of dependence logic where Q is interpreted as "there exists uncountable many." Both of the axiomatizations are shown to be sound and complete for FO(Q) consequences.Comment: 17 page

    A Steering Wheel Reversal Rate Metric for Assessing Effects of Visual and Cognitive Secondary Task Load

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    This paper presents a steering wheel reversal rate metric intended for assessment of the effects of secondary tasks, such as interacting with in-vehicle information systems, on vehicle lateral control performance. The metric was compared to a number of other common steering wheel metrics with respect to the sensitivity to visual and cognitive secondary task load. It was shown that the proposed reversal rate metric, together with the existing steering entropy metric, was the most sensitive across experimental conditions. Different parameter settings for the metric were systematically investigated and suitable values for capturing the effects of visual and cognitive secondary task load recommended

    Homogenization of random degenerated nonlinear monotone operators

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    This paper deals with homogenization of random nonlinear monotone operators in divergence form. We assume that the structure conditions (strict monotonicity and continuity conditions) degenerate and are given in terms of a weight function. Under proper integrability assumptions on the weight function we construct the effective operator and prove the homogenization result

    Bildskärmsarbetarens primära arbetsmiljö : orsakssamband till utmattning ochmuskuloskeletala besvär

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    Only abstract. Paper copies of master’s theses are listed in the Helka database (http://www.helsinki.fi/helka). Electronic copies of master’s theses are either available as open access or only on thesis terminals in the Helsinki University Library.Vain tiivistelmä. Sidottujen gradujen saatavuuden voit tarkistaa Helka-tietokannasta (http://www.helsinki.fi/helka). Digitaaliset gradut voivat olla luettavissa avoimesti verkossa tai rajoitetusti kirjaston opinnäytekioskeilla.Endast sammandrag. Inbundna avhandlingar kan sökas i Helka-databasen (http://www.helsinki.fi/helka). Elektroniska kopior av avhandlingar finns antingen öppet på nätet eller endast tillgängliga i bibliotekets avhandlingsterminaler.Arbete med datorer blir allt vanligare. De flesta kontorsarbetare idag jobbar med bildskärmsarbete största delen av arbetsdagen, vilket innebär att man sitter på samma plats en stor del av sin tid. Därför är det viktigt att man fäster uppmärksamhet på bildskärmsarbetarens primära arbetsomgivning. I och med att bildskärmsarbete blivit vanligare har också förekomsten av utmattning ökat. Likaså har förekomsten av muskuloskeletetala besvär, speciellt problem i nacke och axlar tilltagit. Tidigare undersökningar har också visat ett starkt samband mellan dessa. Utmattning antas i flera undersökningar starkt korrelera med muskuloskeletala besvär. Dessutom förknippas såväl utmattning som muskuloskeletala besvär ofta med låg arbetstillfredställelse, sämre arbetseffektivitet och långa sjukledigheter. Bildskärmsarbetarens primära arbetsmiljö innefattar många faktorer som antas påverka individens hälsa. Såväl psykosociala faktorer, såsom arbetets krav, egenkontroll och socialt stöd, och fysiska faktorer, såsom luftkvalitet och ergonomi, antas påverka förekomsten av ohälsa. Därför är det viktigt att utreda sambanden mellan dessa faktorer. Syftet med undersökningen är att påvisa hur faktorer i den psykosociala arbetsmiljön i samband med upplevelsen av den fysiska arbetsmiljön hos bildskärmarbetare påverkar utmattning och muskuloskeletala besvär. Problemet undersöks genom fyra hypoteser. Först utreds hur kombinationer av de psykosociala faktorerna, arbetskrav, egenkontroll och socialt stöd, samvarierar med utmattning genom variansanalys. Därefter undersöks sambandet mellan den psykosociala arbetsmiljön och den fysiska arbetsmiljön och deras inverkan på utmattning och muskuloskeletala besvär. Till sist granskades variansen mellan utmattning och muskuloskeletala besvär. Undersökningen är en tvärsnittsundersökning gjord bland personer som huvudsakligen arbetar med bildskärmsarbete inom Helsingfors universitets administration och på Folkpensionanstalten i Päijät-Tavastland. Tillsammans deltog 286 personer i undersökningen. Resultatet av undersökningen visar signifikanta samband mellan såväl den psykosociala som den fysiska arbetsmiljön och utmattning samt muskuloskeletala besvär. I denna undersökning förklarar psykosociala faktorer en större del av förekomsten av utmattning och muskuloskeletala besvär än fysiska faktorer. Däremot påverkar de fysiska faktorerna sambandet ytterligare

    Survival of Clostridium perfringens During Simulated Transport and Stability of Some Plasmid-borne Toxin Genes under Aerobic Conditions

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    Clostridium perfringens is a pathogen of great concern in veterinary medicine, because it causes enteric diseases and different types of toxaemias in domesticated animals. It is important that bacteria in tissue samples, which have been collected in the field, survive and for the classification of C. perfringens into the correct toxin group, it is crucial that plasmid-borne genes are not lost during transportation or in the diagnostic laboratory. The objectives of this study were to investigate the survival of C. perfringens in a simulated transport of field samples and to determine the stability of the plasmid-borne toxin genes cpb1 and etx after storage at room temperature and at 4°C. Stability of the plasmid-borne genes cpb1 and etx of C. perfringens CCUG 2035, and cpb2 from C. perfringens CIP 106526, JF 2255 and 6 field isolates in aerobic atmosphere was also studied. Survival of C. perfringens was similar in all experiments. The cpb1 and etx genes were detected in all isolates from samples stored either at room temperature or at 4°C for 24–44 h. Repeated aerobic treatment of C. perfringens CCUG 2035 and CIP 106526 did not result in the loss of the plasmid-borne genes cpb1, cpb2 or etx. Plasmid-borne genes in C. perfringens were found to be more stable than generally reported. Therefore, C. perfringens toxinotyping by PCR can be performed reliably, as the risk of plasmid loss seems to be a minor problem

    A 2-pyridone-amide inhibitor targets the glucose metabolism pathway of Chlamydia trachomatis.

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    UnlabelledIn a screen for compounds that inhibit infectivity of the obligate intracellular pathogen Chlamydia trachomatis, we identified the 2-pyridone amide KSK120. A fluorescent KSK120 analogue was synthesized and observed to be associated with the C. trachomatis surface, suggesting that its target is bacterial. We isolated KSK120-resistant strains and determined that several resistance mutations are in genes that affect the uptake and use of glucose-6-phosphate (G-6P). Consistent with an effect on G-6P metabolism, treatment with KSK120 blocked glycogen accumulation. Interestingly, KSK120 did not affect Escherichia coli or the host cell. Thus, 2-pyridone amides may represent a class of drugs that can specifically inhibit C. trachomatis infection.ImportanceChlamydia trachomatis is a bacterial pathogen of humans that causes a common sexually transmitted disease as well as eye infections. It grows only inside cells of its host organism, within a parasitophorous vacuole termed the inclusion. Little is known, however, about what bacterial components and processes are important for C. trachomatis cellular infectivity. Here, by using a visual screen for compounds that affect bacterial distribution within the chlamydial inclusion, we identified the inhibitor KSK120. As hypothesized, the altered bacterial distribution induced by KSK120 correlated with a block in C. trachomatis infectivity. Our data suggest that the compound targets the glucose-6-phosphate (G-6P) metabolism pathway of C. trachomatis, supporting previous indications that G-6P metabolism is critical for C. trachomatis infectivity. Thus, KSK120 may be a useful tool to study chlamydial glucose metabolism and has the potential to be used in the treatment of C. trachomatis infections

    VAScular and Chronic Obstructive Lung disease (VASCOL): a longitudinal study on morbidity, symptoms and quality of life among older men in Blekinge county, Sweden

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    Purpose: Despite data showing breathlessness to be more prevalent in older adults, we have little detail about the severity or multidimensional characteristics of breathlessness and other self-reported measures (such as quality of life and other cardiorespiratory-related symptoms) in this group at the population level. We also know little about the relationship between multidimensional breathlessness, other symptoms, comorbidities and future clinical outcomes such as quality of life, hospitalisation and mortality. This paper reports the design and descriptive findings from the first two waves of a longitudinal prospective cohort study in older adults. Participants: Between 2010 and 2011, 1900 men in a region in southern Sweden aged 65 years were invited to attend for VAScular and Chronic Obstructive Lung disease (VASCOL) baseline (Wave 1) assessments which included physiological measurements, blood sampling and a self-report survey of lifestyle and previous medical conditions. In 2019, follow-up postal survey data (Wave 2) were collected with additional self-report measures for breathlessness, other symptoms and quality of life. At each wave, data are cross-linked with nationwide Swedish registry data of diseases, treatment, hospitalisation and cause of death. Findings to date: 1302/1900 (68%) of invited men participated in Wave 1, which include 56% of all 65-year-old men in the region. 5% reported asthma, 2% chronic obstructive pulmonary disease, 56% hypertension, 10% diabetes and 19% had airflow limitation. The VASCOL cohort had comparable characteristics to those of similarly aged men in Sweden. By 2019, 109/1302 (8.4%) had died. 907/1193 (76%) of the remainder participated in Wave 2. Internal data completeness of 95% or more was achieved for most Wave 2 measures. Future plans: A third wave will be conducted within 4 years, and the cohort will be followed through repeated follow-ups planned every fourth year, as well as national registry data of diagnosis, treatments and cause of death

    Modeling driver control behavior in both routine and near-accident driving

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    Building on ideas from contemporary neuroscience, a framework is proposed in which drivers’ steering and pedal behavior is modeled as a series of individual control adjustments, triggered after accumulation of sensory evidence for the need of an adjustment, or evidence that a previous or ongoing adjustment is not achieving the intended results. Example simulations are provided. Specifically, it is shown that evidence accumulation can account for previously unexplained variance in looming detection thresholds and brake onset timing. It is argued that the proposed framework resolves a discrepancy in the current driver modeling literature, by explaining not only the short-latency, well-tuned, closed-loop type of control of routine driving, but also the degradation into long-latency, ill-tuned open-loop control in more rare, unexpected, and urgent situations such as near-accidents
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