3,304 research outputs found

    Gravitational waves from binary systems in circular orbits: Convergence of a dressed multipole truncation

    Get PDF
    The gravitational radiation originating from a compact binary system in circular orbit is usually expressed as an infinite sum over radiative multipole moments. In a slow-motion approximation, each multipole moment is then expressed as a post-Newtonian expansion in powers of v/c, the ratio of the orbital velocity to the speed of light. The bare multipole truncation of the radiation consists in keeping only the leading-order term in the post-Newtonian expansion of each moment, but summing over all the multipole moments. In the case of binary systems with small mass ratios, the bare multipole series was shown in a previous paper to converge for all values v/c < 2/e, where e is the base of natural logarithms. In this paper, we extend the analysis to a dressed multipole truncation of the radiation, in which the leading-order moments are corrected with terms of relative order (v/c)^2 and (v/c)^3. We find that the dressed multipole series converges also for all values v/c < 2/e, and that it coincides (within 1%) with the numerically ``exact'' results for v/c < 0.2.Comment: 9 pages, ReVTeX, 1 postscript figur

    Sensor-Based Intelligent Traffic Light Control System: A Panacea to Traffic Congestion in Nigerian Motorways

    Get PDF
    Traffic congestion is one of the major problems in our nation motorways. As a result, many man-hours are being lost on daily bases. Traffic congestion occurs when a volume of traffic or modal split generates demand for space greater than the available road capacity. There are a number of specific circumstances which cause or aggravate congestion; most of them reduce the capacity of a road at a given point or over a certain length, or increase the number of vehicles required for a given volume of people or goods. It is the impedance vehicles impose on each other, due to the speed-flow relationship, in conditions where the use of a transport system approaches capacity. It has been causing many critical problems and challenges in the major and most populated cities. Due to these congestion problems, people lose time, miss opportunities, and get frustrated. There is also loss in productivity from workers, trade opportunities are lost, and delivery gets delayed. Health hazards are on the increase due to emission of carbon dioxide from the exhausts of idling vehicles on the roads. Accident risks are also escalating as traffic density increases. Traffic congestion is essentially a relative phenomenon that is linked to the difference between the roadway system performance that users expect and how the system actually performs. The congestion control system available has not yielded the needed result as they are pre-timed in which case, each lane will be allocated a pre-signed time even when there is no vehicle on queue. Hence, the need for a knowledge-based system which can use pressure sensors/switches that can know and keep track of vehicular movement on each lane so as to be able to influence appropriately the timing allocated to each of the traffic lights pointing at the roads. This removes the normal allocation of same timing to the lane that has less or no vehicle at all and allocates it to that with higher vehicular density. This paper is aimed at showing how a Sensor-based Intelligent Traffic Light Control System can be employed to significantly enhance traffic congestion management and to effectively manage traffic jam and incidents, reduce pollution and improved public transport services and by implication reduce accidents on our road junctions and the health hazards associated with it. Keywords: Sensor, Congestion, Traffic Signal, Stop Light, Traffic Lamp, Semaphore

    Thromboembolic and neurologic sequelae of discontinuation of an antihyperlipidemic drug during ongoing warfarin therapy

    Get PDF
    Warfarin and antihyperlipidemics are commonly co-prescribed. Some antihyperlipidemics may inhibit warfarin deactivation via the hepatic cytochrome P450 system. Therefore, antihyperlipidemic discontinuation has been hypothesized to result in underanticoagulation, as warfarin metabolism is no longer inhibited. We quantified the risk of venous thromboembolism (VTE) and ischemic stroke (IS) due to statin and fibrate discontinuation in warfarin users, in which warfarin was initially dose-titrated during ongoing antihyperlipidemic therapy. Using 1999-2011 United States Medicaid claims among 69 million beneficiaries, we conducted a set of bidirectional self-controlled case series studies-one for each antihyperlipidemic. Outcomes were hospital admissions for VTE/IS. The risk segment was a maximum of 90 days immediately following antihyperlipidemic discontinuation, the exposure of interest. Time-varying confounders were included in conditional Poisson models. We identified 629 study eligible-persons with at least one outcome. Adjusted incidence rate ratios (IRRs) for all antihyperlipidemics studied were consistent with the null, and ranged from 0.21 (0.02, 2.82) for rosuvastatin to 2.16 (0.06, 75.0) for gemfibrozil. Despite using an underlying dataset of millions of persons, we had little precision in estimating IRRs for VTE/IS among warfarin-treated persons discontinuing individual antihyperlipidemics. Further research should investigate whether discontinuation of gemfibrozil in warfarin users results in serious underanticoagulation

    ORGANIZATIONAL CITIZENSHIP BEHAVIOR AND LEADER-MEMBER EXCHANGE AS CORRELATES OF WORKPLACE VIOLENCE AMONG WORKERS: MODERATING ROLE OF AUTONOMY

    Get PDF
    The present study investigated the moderating role of autonomy in the relationship among organizational citizenship behaviours, leader member exchange and workplace violence. Two hundred and twenty (220) non-teaching staff of Nnamdi Azikiwe University, Awka campus participated in the study. They comprised of 176 females and 44 males. Their age ranged from 22 to 53 years with their mean age of 33.1yearsand standard deviation of 5.7. Four instruments were adopted in the study, namely 12-item workplace violence scale developed by Wang (2002), 20-item organizational citizenship behavior scale developed by Spector, Fox, Goh, Brussema & Kessler (2012), 11-item leader member exchange scale developed by Graen and Taylor (2004). Correlational design was employed for the study. Pearson product moment correlation statistics and multiple regression were also employed as the statistical tool to test the 4 hypotheses generated. The results of the hypotheses tested showed that organizational citizenship behavior positively and significantly correlated with workplace violence (r=.88,

    Redox-Based Probes for Protein Tyrosine Phosphatases

    Full text link
    No AbstractPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83769/1/4423_ftp.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/83769/2/anie_201007871_sm_miscellaneous_information.pd

    Novel actions of next-generation taxanes benefit advanced stages of prostate cancer.

    Get PDF
    PURPOSE: To improve the outcomes of patients with castration-resistant prostate cancer (CRPC), there is an urgent need for more effective therapies and approaches that individualize specific treatments for patients with CRPC. These studies compared the novel taxane cabazitaxel with the previous generation docetaxel, and aimed to determine which tumors are most likely to respond. EXPERIMENTAL DESIGN: Cabazitaxel and docetaxel were compared via in vitro modeling to determine the molecular mechanism, biochemical and cell biologic impact, and cell proliferation, which was further assessed ex vivo in human tumor explants. Isogenic pairs of RB knockdown and control cells were interrogated in vitro and in xenograft tumors for cabazitaxel response. RESULTS: The data herein show that (i) cabazitaxel exerts stronger cytostatic and cytotoxic response compared with docetaxel, especially in CRPC; (ii) cabazitaxel induces aberrant mitosis, leading to pyknotic and multinucleated cells; (iii) taxanes do not act through the androgen receptor (AR); (iv) gene-expression profiling reveals distinct molecular actions for cabazitaxel; and (v) tumors that have progressed to castration resistance via loss of RB show enhanced sensitivity to cabazitaxel. CONCLUSIONS: Cabazitaxel not only induces improved cytostatic and cytotoxic effects, but also affects distinct molecular pathways, compared with docetaxel, which could underlie its efficacy after docetaxel treatment has failed in patients with CRPC. Finally, RB is identified as the first potential biomarker that could define the therapeutic response to taxanes in metastatic CRPC. This would suggest that loss of RB function induces sensitization to taxanes, which could benefit up to 50% of CRPC cases

    Tyrosine Phosphorylation of Botulinum Neurotoxin Protease Domains

    Get PDF
    Botulinum neurotoxins are most potent of all toxins. Their N-terminal light chain domain (Lc) translocates into peripheral cholinergic neurons to exert its endoproteolytic action leading to muscle paralysis. Therapeutic development against these toxins is a major challenge due to their in vitro and in vivo structural differences. Although three-dimensional structures and reaction mechanisms are very similar, the seven serotypes designated A through G vastly vary in their intracellular catalytic stability. To investigate if protein phosphorylation could account for this difference, we employed Src-catalyzed tyrosine phosphorylation of the Lc of six serotypes namely LcA, LcB, LcC1, LcD, LcE, and LcG. Very little phosphorylation was observed with LcD and LcE but LcA, LcB, and LcG were maximally phosphorylated by Src. Phosphorylation of LcA, LcB, and LcG did not affect their secondary and tertiary structures and thermostability significantly. Phosphorylation of Y250 and Y251 made LcA resistant to autocatalysis and drastically reduced its kcat/Km for catalysis. A tyrosine residue present near the essential cysteine at the C-terminal tail of LcA, LcB, and LcG was readily phosphorylated in vitro. Inclusion of a competitive inhibitor protected Y426 of LcA from phosphorylation, shedding light on the role of the C-terminus in the enzyme’s substrate or product binding

    Beta cell function in type 1 diabetes determined from clinical and fasting biochemical variables

    Get PDF
    AIMS/HYPOTHESIS: Beta cell function in type 1 diabetes is commonly assessed as the average plasma C-peptide concentration over 2 h following a mixed-meal test (CPAVE). Monitoring of disease progression and response to disease-modifying therapy would benefit from a simpler, more convenient and less costly measure. Therefore, we determined whether CPAVE could be reliably estimated from routine clinical variables. METHODS: Clinical and fasting biochemical data from eight randomised therapy trials involving participants with recently diagnosed type 1 diabetes were used to develop and validate linear models to estimate CPAVE and to test their accuracy in estimating loss of beta cell function and response to immune therapy. RESULTS: A model based on disease duration, BMI, insulin dose, HbA1c, fasting plasma C-peptide and fasting plasma glucose most accurately estimated loss of beta cell function (area under the receiver operating characteristic curve [AUROC] 0.89 [95% CI 0.87, 0.92]) and was superior to the commonly used insulin-dose-adjusted HbA1c (IDAA1c) measure (AUROC 0.72 [95% CI 0.68, 0.76]). Model-estimated CPAVE (CPEST) reliably identified treatment effects in randomised trials. CPEST, compared with CPAVE, required only a modest (up to 17%) increase in sample size for equivalent statistical power. CONCLUSIONS/INTERPRETATION: CPEST, approximated from six variables at a single time point, accurately identifies loss of beta cell function in type 1 diabetes and is comparable to CPAVE for identifying treatment effects. CPEST could serve as a convenient and economical measure of beta cell function in the clinic and as a primary outcome measure in trials of disease-modifying therapy in type 1 diabetes
    corecore