483 research outputs found
The End Magnets of the Ifusp Race-track Microtron Booster
The end magnets of the IFUSP race-track microtron booster, second stage of the electron accelerator under construction at the Linear Accelerator Laboratory, are presented. They deflect, focus and return the beam to the accelerating section. Details about the project are discussed, Poisson code was used to give the final geometry of the end magnets. The end magnets incorporate auxiliary pole pieces (clamps) which create a reverse fringe field region that avoids the beam vertical defocusing and reduces the horizontal displacement produced by extended fringe fields (EFF). The small gap height used for the clamps provided reverse field distributions with fringe fields of short extensions, avoiding the traditional use of inactive clamps. Measurements and calculations concerning particle trajectories and reverse field distribution are presented. The floating wire technique, employing an original procedure to register orbits, was used to corroborate the calculated beam trajectories and represents a good experimental option in the lack of the accelerator beam. The experimental results showed agreement of about 0.1% with the calculations
Identificación de parvovirus canino tipo 2C en cachorros de Nicaragua
Objetivo. Identificar los genotipos de parvovirus canino-circulantes en cachorros en dos municipios de Nicaragua.
Materiales y métodos. Se recolectaron muestras por hisopado rectal de 45 cachorros con y sin antecedentes de vacunación, con menos 6 meses de edad, con y sin sintomatología compatible con parvovirosis. Las muestras y dos de las vacunas que se comercializan en Nicaragua (vacuna nº1 y vacuna nº2) fueron analizadas por Reacción en Cadena de la Polimerasa (PCR) convencional para un producto de ˜ 630 pb del gen VP2. Además, se secuenciaron en sentido inverso cuatro muestras de campo elegidas al azar y ambas cepas de vacunas.
Resultados. El 28.9% (13/45) de las muestras analizadas fueron positivas en PCR. No se encontraron diferencias significativas en la detección por PCR del fragmento de VP2, respecto al estado de vacunación de los animales (p=0.05). Las cuatro muestras de campo secuenciadas fueron identificadas como genotipo CPV-2C y las dos cepas vacunales se identificaron como genotipo CPV-2A.
Conclusiones. La inferencia evolutiva de las secuencias alineadas de cepas vacunales mostró alta divergencia evolutiva respecto a las cepas de campo. Este hallazgo lleva a replantear el tema sobre la eficacia de las vacunas analizadas en este trabajo y que son aplicadas en Nicaragua.
Objective. To identify genotypes of canine parvovirus circulating in puppies in two municipalities of Nicaragua.
Materials and methods. Rectal swab samples from 45 puppies less under 6 months of age were collected and processed for presence of parvovirus bur conventional PCR technique. Puppies might or not have been vaccinated and with or without parvovirus infection symptoms. Two commercially available parvovirus vaccines in Nicaragua (vaccine no1 and vaccine no2) were also analyzed by conventional Polymerase Chain Reaction (PCR) resulting in a product of approximate to 630 bp of the VP2 gene. In addition, Sanger sequences of four randomly chosen field samples and both vaccine strains were obtained.
Results. 28.9% (13/45) of the analyzed samples were positive by PCR, for CPV VP2 gene. No statistically significant differences (p >= 0.05) were obtained in PCR detection between dogs with or without vaccination history. The four sequenced field samples were identified as CPV-2C genotype while both vaccine strains were identified as CPV-2A genotype.
Conclusions. The aligned sequences showed high evolutionary divergence of filed strains with respect to vaccines strains, leading us to reconsider the efficacy of the analyzed vaccines commercially available in Nicaragua nowadays
The Brand Development Strategy Research of Lilanz Garment Enterprise
随着经济全球化的迅速发展和现代科学技术的不断进步,世界已进入品牌竞争时代。品牌成为衡量一个国家综合经济实力的重要标志。而在这样一个极速变化的市场条件下,在消费者消费观念、消费行为不断变化的背景下,企业如何打造基于消费需求的品牌发展战略,就成为任何一个企业能够在新的市场竞争中立足并获得竞争优势的关键。 改革开放以来,我国服装工业得到迅猛发展,在满足需求、繁荣市场、争创外汇、增加税收、安排就业等方面,为国民经济的发展做出了很大贡献。作为中国最重要的服装生产基地和品牌聚集地,泉州服装产业已经得到了快速发展,形成了从上游的纺织、染整,到下游的成衣制造,再到配套原辅材料的完整产业链和以低成本扩张的低端...With the rapid development of economic globalization and advancement of modern science and technology, the world has entered the era of brand competition. Brand as a measure of a country's overall economic strength of the regiment. In such a speed changing market conditions,the consumer concept of consumption, consumer behavior changing context of consumer demand for enterprises to build on the br...学位:工商管理硕士院系专业:管理学院高级经理教育中心(EMBA项目)_高级管理人员工商管理硕士(EMBA)学号:X200615611
Cardiac Myocardial Disease States Cause Left Ventricular Remodeling with Decreased Contractility and Lead to Heart Failure;Interventions by Coronary Arterial Bypass Grafting and Surgical Ventricular Restoration Can Reverse LV Remodeling with Improved Cont
Biaxial deformation of collagen and elastin fibers in coronary adventitia
The microstructural deformation-mechanical loading relation of the blood vessel wall is essential for understanding the overall mechanical behavior of vascular tissue in health and disease. We employed simultaneous mechanical loading-imaging to quantify in situ deformation of individual collagen and elastin fibers on unstained fresh porcine coronary adventitia under a combination of vessel inflation and axial extension loading. Specifically, the specimens were imaged under biaxial loads to study microscopic deformation-loading behavior of fibers in conjunction with morphometric measurements at the zero-stress state. Collagen fibers largely orientate in the longitudinal direction, while elastin fibers have major orientation parallel to collagen, but with additional orientation angles in each sublayer of the adventitia. With an increase of biaxial load, collagen fibers were uniformly stretched to the loading direction, while elastin fibers gradually formed a network in sublayers, which strongly depended on the initial arrangement. The waviness of collagen decreased more rapidly at a circumferential stretch ratio of λθ = 1.0 than at λθ = 1.5, while most collagen became straightened at λθ = 1.8. These microscopic deformations imply that the longitudinally stiffer adventitia is a direct result of initial fiber alignment, and the overall mechanical behavior of the tissue is highly dependent on the corresponding microscopic deformation of fibers. The microstructural deformation-loading relation will serve as a foundation for micromechanical models of the vessel wall
Geometry of River Networks II: Distributions of Component Size and Number
The structure of a river network may be seen as a discrete set of nested
sub-networks built out of individual stream segments. These network components
are assigned an integral stream order via a hierarchical and discrete ordering
method. Exponential relationships, known as Horton's laws, between stream order
and ensemble-averaged quantities pertaining to network components are observed.
We extend these observations to incorporate fluctuations and all higher moments
by developing functional relationships between distributions. The relationships
determined are drawn from a combination of theoretical analysis, analysis of
real river networks including the Mississippi, Amazon and Nile, and numerical
simulations on a model of directed, random networks. Underlying distributions
of stream segment lengths are identified as exponential. Combinations of these
distributions form single-humped distributions with exponential tails, the sums
of which are in turn shown to give power law distributions of stream lengths.
Distributions of basin area and stream segment frequency are also addressed.
The calculations identify a single length-scale as a measure of size
fluctuations in network components. This article is the second in a series of
three addressing the geometry of river networks.Comment: 16 pages, 13 figures, 4 tables, Revtex4, submitted to PR
Critical contribution of KV1 channels to the regulation of coronary blood flow
Ion channels in smooth muscle control coronary vascular tone, but the mechanisms require further investigation. The purpose of this study was to evaluate the functional role of KV1 channels on porcine coronary blood flow by using the selective antagonist correolide. KV1 channel gene transcripts were found in porcine coronary arteries, with KCNA5 (encoding KV1.5) being most abundant (P<0.001). Immunohistochemical staining demonstrated KV1.5 protein in the vascular smooth muscle layer of both porcine and human coronary arteries, including microvessels. Whole-cell patch clamp experiments demonstrated significant correolide-sensitive (1–10 µM) current in coronary smooth muscle. In vivo studies included direct intracoronary infusion of vehicle or correolide into a pressure-clamped left anterior descending artery of healthy swine (n=5 in each group) with simultaneous measurement of coronary blood flow. Intracoronary correolide (~0.3–3 µM targeted plasma concentration) had no effect on heart rate or systemic pressure, but reduced coronary blood flow in a dose-dependent manner (P<0.05). Dobutamine (0.3–10 µg/kg/min) elicited coronary metabolic vasodilation and intracoronary correolide (3 µM) significantly reduced coronary blood flow at any given level of myocardial oxygen consumption (P<0.001). Coronary artery occlusions (15 s) elicited reactive hyperemia and correolide (3 µM) reduced the flow volume repayment by approximately 30% (P<0.05). Taken together, these data support a major role for KV1 channels in modulating baseline coronary vascular tone and perhaps vasodilation in response to increased metabolism and transient ischemia
Pulsatile blood flow, shear force, energy dissipation and Murray's Law
BACKGROUND: Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. METHODS: To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. RESULTS: For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches) of the arterial system. CONCLUSION: A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law
Epidemiología molecular de Bartonella henselae en gatos callejeros y de albergue en Zaragoza, España
Fundamentos: Bartonella henselae produce la enfermedad del araña- zo del gato en las personas y se considera infradiagnosticada. El objetivo fue detectar y cuantificar la carga de ácido desoxiribonucleico (ADN) de B. henselae en muestras de sangre y orales de gatos callejeros y de albergue de Zaragoza, España y analizar su relación con factores epidemiológicos y clínicos.
Métodos: Se estudiaron 47 gatos. El ADN de B. henselae,se detectó mediante reacción en cadena de la polimerasa en tiempo real (qPCR) en sangre y muestras orales. Se usó el paquete estadístico SPSS para analizar la positividad de las muestras pareadas y su relación con factores epidemioló- gicos (edad, sexo, origen, mes de muestreo, presencia de pulgas/garrapatas) y clínicos (estado de salud y presencia de lesiones orales). Se realizó un análisis de regresión logística para conocer la asociación entre la presencia en sangre y cavidad oral y el resto de las variables.
Resultados: el 23,40% de las muestras de sangre y el 27,65% de las orales portaba el ADN de B. henselae. Se observó débil correlación de la positividad de las muestras pareadas (kappa= 0,33; p 0,05) entre la presencia de ADN de B. henselae en las muestras y los factores epidemiológicos y clínicos. Los gatos con lesiones orales portaban una carga más elevada de ADN (3,12/1x106 células) en la boca que los que no tenían lesiones (2,58 /1por106 células), (p=0,032).
Conclusiones: La detección de ADN de B. henselae en sangre no pare- ce estar relacionada con su presencia en cavidad oral y viceversa. Los gatos positivos con lesiones orales pueden significar mayor riesgo de infección por B. henselae para las personas que los manejan
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