456 research outputs found
Constraints on a Parity-Conserving/Time-Reversal-Non-Conserving Interaction
Time-Reversal-Invariance non-conservation has now been unequivocally
demonstrated in a direct measurement at CPLEAR. What about tests of
time-reversal-invariance in systems other than the kaon system? Tests of
time-reversal-invariance belong to two classes: searches for parity violating
(P-odd)/time-reversal-invariance-odd (T-odd) interactions, and for P-even/T-odd
interactions (assuming CPT conservation this implies C-conjugation
non-conservation). Limits on a P-odd/T-odd interaction follow from measurements
of the electric dipole moment of the neutron (with a present upper limit of 6 x
10^-26 e.cm [95% C.L.]). It provides a limit on a P-odd/T-odd pion-nucleon
coupling constant which is less than 10^-4 times the weak interaction strength.
Experimental limits on a P-even/T-odd interaction are much less stringent.
Following the standard approach of describing the nucleon-nucleon interaction
in terms of meson exchanges, it can be shown that only charged rho-meson
exchange and A_1 meson exchange can lead to a P-even/T-odd interaction. The
better constraints stem from measurements of the electric dipole moment of the
neutron and from measurements of charge-symmetry breaking in neutron-proton
elastic scattering. The latter experiments were executed at TRIUMF (497 and 347
MeV) and at IUCF (183 MeV). Weak decay experiments may provide limits which
will possibly be comparable. All other experiments, like gamma decay
experiments, detailed balance experiments, polarization - analyzing power
difference determinations, and five-fold correlation experiments with polarized
incident nucleons and aligned nuclear targets, have been shown to be at least
an order of magnitude less sensitive.Comment: 15 pages LaTeX, including 5 PostScript figures. Uses ijmpe1.sty. To
appear in International Journal of Modern Physics E (IJMPE). Slight change in
short abstrac
Modal Rayleigh-like streaming in layered acoustofluidic devices
Classical Rayleigh streaming is well known and can be modelled using Nyborg’s limiting velocity method as driven by fluid velocities adjacent to the walls parallel to the axis of the main acoustic resonance. We have demonstrated previously the existence and the mechanism of four-quadrant transducer plane streaming patterns in thin-layered acoustofluidic devices which are driven by the limiting velocities on the walls perpendicular to the axis of the main acoustic propagation. We have recently found experimentally that there is a third case which resembles Rayleigh streaming but is a more complex pattern related to three-dimensional cavity modes of an enclosure. This streaming has vortex sizes related to the effective wavelength in each cavity axis of the modes which can be much larger than those found in the one-dimensional case with Rayleigh streaming. We will call this here modal Rayleigh-like streaming and show that it can be important in layered acoustofluidic manipulation devices. This paper seeks to establish the conditions under which each of these is dominant and shows how the limiting velocity field for each relates to different parts of the complex acoustic intensity patterns at the driving boundaries
Predicting mobility using limited data during early stages of a pandemic
The COVID-19 pandemic has changed consumer behavior substantially. In this study, we explore the drivers of consumer mobility in several metropolitan areas in the United States under the perceived risks of COVID-19. We capture multiple dimensions of perceived risk using local and national cases and death counts of COVID-19, along with real-time Google Trends data for personal protective equipment (PPE). While Google Trends data are popular inputs in many studies, the risk of multicollinearity escalates with the addition of more relevant terms. Therefore, multicollinearity-alleviating methods are needed to appropriately leverage information provided by Google Trends data. We develop and utilize a novel optimization scheme to induce linear models containing strictly significant covariates and minimal multicollinearity. We find that there are a variety of unique factors that drive mobility in different geographic locations, as well as several factors that are common to all locations
Modeling Social Transmission Dynamics of Unhealthy Behaviors for Evaluating Prevention and Treatment Interventions on Childhood Obesity
Research evidence indicates that obesity has spread through social networks, but lever points for interventions based on overlapping networks are not well studied. The objective of our research was to construct and parameterize a system dynamics model of the social transmission of behaviors through adult and youth influence in order to explore hypotheses and identify plausible lever points for future childhood obesity intervention research. Our objectives were: (1) to assess the sensitivity of childhood overweight and obesity prevalence to peer and adult social transmission rates, and (2) to test the effect of combinations of prevention and treatment interventions on the prevalence of childhood overweight and obesity. To address the first objective, we conducted two-way sensitivity analyses of adult-to-child and child-to-child social transmission in relation to childhood overweight and obesity prevalence. For the second objective, alternative combinations of prevention and treatment interventions were tested by varying model parameters of social transmission and weight loss behavior rates. Our results indicated child overweight and obesity prevalence might be slightly more sensitive to the same relative change in the adult-to-child compared to the child-to-child social transmission rate. In our simulations, alternatives with treatment alone, compared to prevention alone, reduced the prevalence of childhood overweight and obesity more after 10 years (1.2–1.8% and 0.2–1.0% greater reduction when targeted at children and adults respectively). Also, as the impact of adult interventions on children was increased, the rank of six alternatives that included adults became better (i.e., resulting in lower 10 year childhood overweight and obesity prevalence) than alternatives that only involved children. The findings imply that social transmission dynamics should be considered when designing both prevention and treatment intervention approaches. Finally, targeting adults may be more efficient, and research should strengthen and expand adult-focused interventions that have a high residual impact on children
Analysis of Adipokines and some Steroid Hormones in Myocardial Infarction
الموت الشامل بسبب أمراض القلب والأوعية الدموية هو السبب السائد للوفاة، ومرض القلب الإقفاري هو السبب البارز. هناك ميل لزيادة حساسية الأساليب في المختبر المعاصر لتشخيص الأمراض القلبية الوعائية، وتقييم المفتاح كمؤشرات حيوية للأمراض القلبية الوعائية. المهمة العاجلة هي البحث عن مؤشرات مختلفة كأداة للكشف المبكر عن احتشاء عضلة القلب ومراقبته. ضمت هذه المحاولة ١١٧ متطوعًا، تم تسجيلهم من كلا الجنسين في الفئة العمرية من ٣٢ إلى ٦٤ عامًا. تم تصنيف المتطوعين إلى مجموعتين: ٦٧ مريضًا من احتشاء عضلة القلب، واحتضنت المجموعات الأخرى ٥٠ فردًا سليمًا. تم جمع عينات الدم وتوجيهها للتحليل الكيميائي الحيوي لتقييم مستويات هرمون الاستراديول والتستوستيرون والبروجسترون والأديبونكتين واللبتين والدهون في كل مجموعة. بناءً على التقييم الإحصائي لمعلمات المؤشر الحيوي، يمكن الإعلان عن الاستنتاج التالي من هذه الدراسة، وهو انخفاض كبير في مستويات هرمون التستوستيرون والبروتين الدهني عالي الكثافة (P <0.001) في احتشاء عضلة القلب، ضمن P <0.061 المرتفعة بشكل ملحوظ من مستويات البروجسترون في عضلة القلب مرضى الاحتشاء بالمقارنة مع الأفراد الأصحاء. أشارت الاختبارات الكيميائية الحيوية المتبقية إلى مستويات مرتفعة بشكل ملحوظ في المرضى الذين يعانون من احتشاء عضلة القلب مثل استراديول (P <0.001) ، أديبونكتين (P <0.001)، ليبتين (P <0.001) ، الكلي الكوليسترولالكوليسترول (P <0.001) ، الدهون الثلاثية P) <0.001) ومستويات البروتين الدهني منخفض الكثافة ) P <0.001). تُظهر الأديبوكينات (أديبونكتين ، لبتين) وبعض هرمونات الستيرويد (استراديول ، هرمون التستوستيرون) أدوارًا حاسمة في تحسين أمراض التمثيل الغذائي والقلب والأوعية الدموية ويمكن استخدامها كمؤشر حيوي للتعرض لاحتشاء عضلة القلب، والسلوك الطبي والشدة. يقدم هذا الإقرار التشخيص المبكر للمرض وتطوره.The most common cause of death is cardiovascular disease (CVD), with ischemic heart disease being the most notable type. There is a propensity to raise the sensitivity of methods in contemporary laboratory for diagnosing of CVD, and assessing key as CVD bio-indicators. The urgent task is to seek for different indicators as a hopeful tool for early detection and monitoring of myocardial infarction in blood samples only. This study comprised 117 Volunteers, recorded with both genders in the age range of 32-64 years old. The volunteers were categorized into two groups: 67patients of myocardial infarction, other group embraced 50 healthy individuals. The samples of blood were collected and directed for biochemical analysis to evaluate estradiol, testosterone, progesterone, adiponectin, leptin, and lipid profile [total cholesterol, triglycerides, high density lipoprotein (HDL), and low-density lipoprotein (LDL)] levels in each group. The following conclusion can be drawn from this study based on statistical assessment of bio-indicator parameters, significantly reduced of testosterone and HDL (P <0.001) levels in myocardial infarction, within non-significantly elevated P <0.061 of progesterone levels in myocardial infarction patients as compared with healthy individuals. The remaining biochemical tests indicated significantly elevated levels in patients with myocardial infarction such as estradiol (P <0.001), adiponectin (P <0.001), leptin (P <0.001), total cholesterol (P <0.001), triglycerides (P <0.001) and LDL (P <0.001) levels. Adipokines (adiponectin, leptin) and some steroid hormones (estradiol, testosterone) show crucial roles in the improvement of metabolic and cardiovascular diseases and may be utilized as bio-pointer for myocardial infarction exposure, medical conduct and severity. This acknowledgment offers early diagnosis of disease and progression.
Affinity-Division Multiplexing for Molecular Communications with Promiscuous Ligand Receptors
A key challenge in Molecular Communications (MC) is low data transmission
rates, which can be addressed by channel multiplexing techniques. One way to
achieve channel multiplexing in MC is to leverage the diversity of different
molecule types with respect to their receptor binding characteristics, such as
affinity and kinetic binding/unbinding rates. In this study, we propose a
practical multiplexing scheme for MC, which is based on the diversity of
ligand-receptor binding affinities. This method requires only a single type of
promiscuous receptor on the receiver side, capable of interacting with multiple
ligand types. We analytically derive the mean Bit Error Probability (BEP) over
all multiplexed MC channels as a function of similarity among ligands in terms
of their receptor affinities, the number of receptors, the number of
multiplexed channels, and the ratio of concentrations encoding bit-1 and bit-0.
We investigate the impact of each design parameter on the performance of
multiplexed MC system
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Reprint of "Decision support models for supplier development: Systematic literature review and research agenda"
The continuing trend towards sourcing components and semi-finished goods for less vertically integrated manufacturing systems globally leads to a dramatic increase in supply options for companies. To ensure that companies benefit from the potentials global sourcing offers, supplier-buyer relationships need to be managed efficiently. Due to the decreasing share of value-adding activities provided in-house, suppliers are more and more considered as an essential contributor to the buying company's competitive position. Consequently, to realize and sustain competitive advantages, companies try to establish institutionalized long-term relationships to their most important suppliers and to actively improve the productivity and performance of their supplier base. To support supplier development in practice, researchers have developed decision support models that provide assistance in selecting and implementing suitable supplier development activities.
The aim of this paper is to provide a comprehensive and systematic overview of decision support models for supplier development and to develop a research agenda that helps to identify promising areas for future research in this area. First, typical applications for supplier development as well as potential development measures that can be adopted to improve the performance of suppliers are identified. Secondly, a systematic literature review with a focus on decision support models for supplier development is conducted. Based on the analysis of the literature, we define a research agenda that synthesizes key trends and promising research opportunities and thus highlight areas where more decision support models are needed to foster supplier development initiatives in practice
Clinical significance of salivary, serum, nitric oxide, and arginase in breast cancer
Background: Breast cancer is the most commonly diagnosed cancer among females. A source of sampling for clinical diagnosis is saliva which has been utilized and it is a promising approach as collecting saliva is relatively easy and non-invasive. Over the past two decades, utilizing saliva as a biomarker, specifically for early cancer diagnosis has attracted much research interest.
Aim: To alter the sample collection from blood to saliva for some components such as nitric oxide (NO) and arginase, in order to detect an easy, earlier and noninvasive diagnostic test as biomarkers and prognostic tools in patients with breast cancer.
Methods: A total of 73 female volunteers were participated in this study, 25 healthy volunteers compared with 48 patients with breast cancer in order to estimate and compare both salivary and blood level components such as NO and arginase.
Results: The mean blood and salivary samples for both nitric oxide and arginase levels were significantly raised in patients with breast cancer when they compared with controls (p<0.001).
Conclusions: In this study the changing of salivary levels of NO and arginase as compared with blood may be used as a non-invasive diagnostic tool alternative to serum testing component, which were significantly increased in patients with breast cancer in both blood and saliva and also, may be used as biomarkers and tumor progression tests in diagnosing of breast cancer
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A method of strategic evaluation of energy performance of Building Integrated Photovoltaic in the urban context
This paper presents an integrated bottom-up approach aimed at helping those dealing with strategical analysis of installation of Building Integrated Photo Voltaic (BIPV) to estimate the electricity production potential along with the energy needs of urban buildings at the district scale. On the demand side, hourly energy profiles are generated using dynamic building simulation taking into account actual urban morphologies. On the supply side, electricity generated from the system is predicted considering both the direct and indirect components of solar radiation as well as local climate variables. Python-based Algorithm editor Grasshopper is used to interlink four types of modelling and simulation tools as 1) generation of 3-D model, 2) solar radiation analysis, 3) formatting weather files (TMY data set) and 4) dynamic energy demand. The method has been demonstrated for a cluster of 20 buildings located in the Yasar University in Izmir (Turkey), for which it is found the BIPV system could achieve an annual renewable share of 23%, in line with the Renewable Energy Directive target of 20%. Quantitatively-compared demand and supply information at hourly time step shows that only some energy needs can be met by BIPV, so there is a need for an appropriate matching strategy to better exploit the renewable energy potential
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