27,328 research outputs found

    Path count asymptotics and Stirling numbers

    Get PDF
    We obtain formulas for the growth rate of the numbers of certain paths in infinite graphs built on the two-dimensional Eulerian graph. Corollaries are identities relating Stirling numbers of the first and second kinds.Comment: Misprint corrected. To appear in Proc. Amer. Math. So

    Torus invariant divisors

    Full text link
    Using the language of polyhedral divisors and divisorial fans we describe invariant divisors on normal varieties X which admit an effective codimension one torus action. In this picture X is given by a divisorial fan on a smooth projective curve Y. Cartier divisors on X can be described by piecewise affine functions h on the divisorial fan S whereas Weil divisors correspond to certain zero and one dimensional faces of it. Furthermore we provide descriptions of the divisor class group and the canonical divisor. Global sections of line bundles O(D_h) will be determined by a subset of a weight polytope associated to h, and global sections of specific line bundles on the underlying curve Y.Comment: 16 pages; 5 pictures; small changes in the layout, further typos remove

    Differential patterns of PMN-elastase and type III procollagen peptide in knee joint effusions due to acute and chronic sports injuries

    Get PDF
    In 38 traumatic knee joint effusions the proteolytic enzyme PMN-elastase (PMN-E) and the repair marker procollagen III aminoterminal peptide (PIIINP) were determined. According to the period between trauma and first aspiration of the effusion, the patients were divided into 3 groups. Group I (17 patients; period between trauma and first aspiration not longer than 72 hours) showed high concentrations of PMN-E (up to 5400 ng/ml) and low concentrations of PIIINP (<13 U/ml). Group II (11 patients; aspiration within 4 to 14 days) had mean PMN-E and PIIINP concentrations of 125.6 ng/ml and 52.1 U/ ml, respectively. In group III (10 patients, aspiration after 14 days) mean PMN-E concentration was 123.8 ng/ml and mean PIIINP concentration was 63.4 U/ml. Graphic depiction of PMN-E and PIIINP levels in each individual sample as a function of time between trauma and fluid collection revealed highly increasing PMN-E levels during the first 24 posttraumatic hours, followed by rapidly decreasing levels within 72 hours post trauma, and no change after the 4th posttraumatic day. In contrast, PIIINP increased continuously up to the first posttraumatic week and stayed at high levels up to 90 days (end of the observation period). The differential patterns of PMN-E and PIIINP concentration in knee joint effusions may be useful in estimating the period between trauma and first treatment (aspiration of effusion) and should, therefore, be helpful in detecting degenerative lesions, which seem to be characterized by low PMN-E concomitantly with high PIIINP levels

    Does Lipoprotein(a) Inhibit Elastolysis in Abdominal Aortic Aneurysms?

    Get PDF
    AbstractPurpose: to test the hypothesis that there is a negative association between serum levels of lipoprotein(a) (Lp(a)) and elastin-derived peptides (EDP) as well as matrix metalloproteinase (MMP)-9 activation in the aneurysm wall in patients with asymptomatic abdominal aortic aneurysms (AAA).Material and Methods: from 30 patients operated for asymptomatic AAAs, preoperative serum samples and AAA biopsies were collected. Lp(a) (mg/L) and EDP (ng/ml) in serum were measured by enzyme linked immunosorbent assays. MMP-9 activity (arbitrary units) in the AAA wall was measured by gelatin zymography and the ratio: active MMP-9/total MMP-9 were calculated.Results: there was a significant negative correlation (Spearman's rho) between serum levels of Lp(a) and EDP (r=−0.707, p<0.001), as well as the share of activated MMP-9 (r=−0.461, p=0.01) in the AAA wall.Conclusion: this preliminary study indicate that Lp(a) inhibit elastolysis in asymptomatic AAA

    Multiple stressors in a top predator seabird: potential ecological consequences of environmental contaminants, population health and breeding conditions

    Get PDF
    Environmental contaminants may have impacts on reproduction and survival in wildlife populations suffering from multiple stressors. This study examined whether adverse effects of persistent organic pollutants (POPs) increased with poor population health and breeding conditions in three colonies (60–74°N) of great skua (Stercorarius skua) in the north-eastern Atlantic (Shetland, Iceland and Bjørnøya [Bear Island]). POPs (organochlorines [OCs] and polybrominated diphenyl ethers [BDEs]) were measured in plasma of incubating birds (n = 222), concentrations differing nearly tenfold among colonies: Bjørnøya (2009) &gt; Bjørnøya (2010) &gt; Iceland (2009) &gt; Shetland (2009). Reproductive success (hatching success and chick survival) showed that breeding conditions were favourable in Shetland and at Bjørnøya (2010), but were very poor in Iceland and at Bjørnøya (2009). Biomarkers indicated that health was poor in the Shetland population compared to the other populations. Females whose chicks hatched late had high POP concentrations in all colonies except at Bjørnøya (2010), and females losing their eggs at Bjørnøya (2009) tended to have higher concentrations than those hatching. Moreover, there was a negative relationship between female POP concentrations and chick body condition at hatching in Iceland and at Bjørnøya (2010). Supplementary feeding experiments were conducted, and in Iceland where feeding conditions were poor, significant negative relationships were found between female POP concentrations and daily growth-rate in first-hatched chicks of control nests, but not in food supplemented nests. This suggests that negative impacts of POPs were mitigated by improved feeding conditions. For second-chicks, there was a strong negative relationship between the female POP concentrations and growth-rate, but no effects of supplementary feeding. Lowered adult return-rate between breeding seasons with increasing POP loads were found both at Bjørnøya (2009) and in Shetland, especially related to BDEs. This indicates stronger fitness consequences of POPs following seasons with very poor breeding conditions and/or high reproductive effort. This study suggests that the impacts of POPs may differ depending on population health and breeding conditions, and that even low concentrations of POPs could have ecological consequences during adverse circumstances. This is important with regard to risk assessment of biomagnifying contaminants in marine ecosystems

    Prediagnostic presentations of Parkinson's disease in primary care: a case-control study

    Get PDF
    Background: Parkinson’s disease (PD) has an insidious onset and is diagnosed when typical motor features occur. A number of motor and non-motor features may occur during a “pre-diagnostic” phase, reflecting the early disease process. Previously there has been no comprehensive analysis in the general population of the relative magnitude and timing of their association with PD diagnosis. Aim: To assess the association of first presentation of several pre-diagnostic features in primary care with a subsequent diagnosis of PD, and to chart the timeline of these first presentations before diagnosis of PD. Methods: 8,166 individuals with a first diagnosis of PD and 46,755 individuals without PD were identified from 1st January 1996 to 31st December 2012 from The Health Improvement Network, United Kingdom primary care database. Codes were extracted for a wide range of possible pre-diagnostic or early symptoms comprising motor features (tremor, rigidity, balance impairment, neck pain and shoulder pain), autonomic features (constipation, hypotension, dizziness, erectile dysfunction, urinary dysfunction), mental disturbances (memory problems, depression, anxiety) and additional features (fatigue, insomnia) in the years prior to diagnosis. Incidence rates for symptoms recorded in more than 1% of cases per 1000 person years and incidence risk ratio (RR) were calculated and compared for individuals with and without PD at two, five and ten years before diagnosis. Findings: At two years before PD diagnosis the incidence of all examined pre-diagnostic features except neck pain was higher in patients (n=7,232) than in controls (n=40,541). At five years before diagnosis, patients with PD (n=4,769) had higher incidence rates of tremor (RR 13.70 (95%CI 7.82-24.31), balance impairment (RR, 2.19 (95%CI 1.09-4.16), depression (RR 1.76 (95%CI 1.41-2.17), anxiety (RR 1.41 (95%CI 1.09-1.79), constipation (RR 2.24 (95%CI 2.04-2.46), postural hypotension (RR 3.23 (95%CI 1.85-5.52), dizziness (RR 1.99 (95%CI 1.67-2.37), erectile dysfunction (RR 1.30 (95%CI 1.11-1.51), fatigue (RR 1.56 (95%CI 1.27-1.91), and urinary dysfunction (RR 1.96 (95%CI 1.34-2.80) than controls (n=25,544). At ten years before diagnosis of PD the incidence of constipation (RR 2.01 (95%CI 1.62-2.49) and tremor (RR 7.59 (95%CI 1.1-44.8) was already higher in those with later diagnosis with PD (n=1,680) than in controls (n=8,305). Interpretation: This study for the first time provides evidence for a range of pre-diagnostic features that can be detected several years before diagnosis of PD in primary care, estimating the comparative magnitude of risk for each and where they fit in the prodromal timeline. These data on the pre-diagnostic symptoms of PD can be incorporated into ongoing efforts to identify individuals at the earliest stages of the disease in future trials and help understand progression in the earliest phase of PD

    The Unfulfilled Potential of Data-Driven Decision Making in Agile Software Development

    Get PDF
    With the general trend towards data-driven decision making (DDDM), organizations are looking for ways to use DDDM to improve their decisions. However, few studies have looked into the practitioners view of DDDM, in particular for agile organizations. In this paper we investigated the experiences of using DDDM, and how data can improve decision making. An emailed questionnaire was sent out to 124 industry practitioners in agile software developing companies, of which 84 answered. The results show that few practitioners indicated a widespread use of DDDM in their current decision making practices. The practitioners were more positive to its future use for higher-level and more general decision making, fairly positive to its use for requirements elicitation and prioritization decisions, while being less positive to its future use at the team level. The practitioners do see a lot of potential for DDDM in an agile context; however, currently unfulfilled

    High performance positive electrode for a lead-acid battery

    Get PDF
    An electrode suitable for use as a lead-acid battery plate is formed of a paste composition which enhances the performance of the plate. The paste composition includes a basic lead sulfate, a persulfate and water. The paste may also include lead oxide and fibers. An electrode according to the invention is characterized by good strength in combination with high power density, porosity and surface area

    Lower bounds for heights in relative Galois extensions

    No full text
    The goal of this paper is to obtain lower bounds on the height of an algebraic number in a relative setting, extending previous work of Amoroso and Masser. Specifically, in our first theorem, we obtain an effective bound for the height of an algebraic number α\alpha when the base field K\mathbb{K} is a number field and K(α)/K\mathbb{K}(\alpha)/\mathbb{K} is Galois. Our second result establishes an explicit height bound for any nonzero element α\alpha which is not a root of unity in a Galois extension F/K\mathbb{F}/\mathbb{K}, depending on the degree of K/Q\mathbb{K}/\mathbb{Q} and the number of conjugates of α\alpha which are multiplicatively independent over K\mathbb{K}. As a consequence, we obtain a height bound for such α\alpha that is independent of the multiplicative independence condition

    Prototype of NASA's Global Precipitation Measurement Mission Ground Validation System

    Get PDF
    NASA is developing a Ground Validation System (GVS) as one of its contributions to the Global Precipitation Mission (GPM). The GPM GVS provides an independent means for evaluation, diagnosis, and ultimately improvement of GPM spaceborne measurements and precipitation products. NASA's GPM GVS consists of three elements: field campaigns/physical validation, direct network validation, and modeling and simulation. The GVS prototype of direct network validation compares Tropical Rainfall Measuring Mission (TRMM) satellite-borne radar data to similar measurements from the U.S. national network of operational weather radars. A prototype field campaign has also been conducted; modeling and simulation prototypes are under consideration
    corecore