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Unbiased Diffusion to Escape Complex Geometries: Is Reduction to Effective One-Dimensional Description Adequate to Assess narrow Escape Times?

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Applied Mathematics 2014年第8期5卷 1218-1225页

作者： Yoshua chávez Guillermo chacón-Acosta Marco-Vinicio Vázquez Leonardo Dagdug Applied Mathematics and Systems Department Universidad Autónoma Metropolitana-Cuajimalpa México DF México chemistry Department Universidad Autónoma Metropolitana-Iztapalapa México DF México Physics Department Universidad Autónoma Metropolitana-Iztapalapa México DF México

This study is devoted to unbiased diffusion of point Brownian particles inside a tube of varying cross-section (see Figure 1). An expression for the mean survival time, , of the particles inside the tube is obtained in terms of the bulk diffusion constant, D0 and the system’s geometrical parameters, namely, the tube’s axial semi-length, L, the minor radius, , and the slope of the tube’s wall, . Our expression for correctly retrieves the limit behavior of the system under several conditions. We ran Monte Carlo numerical simulations to compute the mean survival time by averaging the survival time of 5 × 104 trajectories, with time step t = 10-6, D0 = 1, and L = 1. The simulations show good agreement with our model. When the geometrical parameters of this system are varied while keeping constant the tube’s enclosed volume, it resembles the problems of narrow Escape Time (J. chem. Phys. 116(22), 9574 (2007)). A previous study on the use of the reduction to effective one-dimension technique (J. Mod. Phys. 2, 284 (2011)) in complex geometries has shown excellent agreement between the theoretical model and numerical simulations. However, in this particular system, the general assumptions of the Hill problem are seemingly inapplicable. The expression obtained shows good agreement with our simulations when 0 ≤ ≤ 1, but fails when grows larger. On the other hand, some errors are found when 0, but the expression holds reasonably well for a broad range of values of . These comparisons between simulations and theoretical predictions, and the expressions obtained for , are the main results of this work.

关键词： Component Formatting Style Styling Insert

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characteristics of ionospheric scintillation climatology over Indian low-latitude region during the 24th solar maximum period

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Geodesy and Geodynamics 2019年第2期10卷 110-117页

作者： K.Sahithi M.Sridhar Sarat K.Kotamraju K.ch.Sri Kavya G.Sivavaraprasad D.Venkata Ratnam ch.Deepthi Department of Electronics and Communication Engineering Koneru Lakshamaiah Education Foundation

The amplitude and phase of L-band satellite signals are fluctuated randomly due to small scale electron density irregularity structures in the ionosphere which result in fleeting variations, known as 'ionospheric scintillations'. The Global navigation Satellite System(GnSS) is a profound remote sensing tool to monitor, model and forecast the ionospheric weather conditions. In this paper, the GnSS amplitude scintillation data has been analyzed during the year 2013 at Bengaluru(12.9°n, 77.59°E) and Lucknow(26.8467°n, 80.9462°E) stations to reinforce climatology of ionospheric scintillation over Indian low-latitude region. The probability of scintillation occurrence and their variations over equatorial and Equatorial Ionization Anomaly(EIA) regions in India are analyzed during various geomagnetic quiet and disturbed days, months and seasons. The annual occurrence of amplitude scintillations are mapped with the function of local time. It is observed from the experimental results that the probability of scintillations occurrences is higher over EIA region than over the equatorial region. The probability of scintillations is higher during March equinox and December solstice, and lowest during June *** of scintillations is intense during post-sunset period. The maximum percentage of scintillation occurrences at the two stations are recorded in november. Moreover, the highest percentage of scintillation occurrences took place on storm day(March 17, 2013) at the two stations. This work would be helpful for understanding the features of GnSS amplitude scintillations over Southern and northern Indian regions. Moreover, these kinds of investigations are helpful for developing new algorithms to nowcast and forecast ionospheric scintillations over Indian Sub-continent.

关键词： GnSS Ionospheric scintillations Indian low-latitude region

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Study nanostructure of a Biomaterial with Medicine Therapeutic Activity

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Microscopy Research 2016年第2期4卷 32-38页

作者： Marilú chávez-Castillo Martha Lilia Domínguez-Patiño Rosa María Melgoza-Alemán Centro de Investigación en Ingeniería y Ciencias Aplicadas Universidad Autónoma del Estado de Morelos Cuernavaca México Facultad de Ciencias Químicas e Ingeniería Universidad Autónoma del Estado de Morelos Cuernavaca México

In Mexico, the medicinal plants have been for used since ancient times and still continue to use by rural populations to treat conditions such as infectious diseases (skin, gastrointestinal or respiratory), metabolics, inflammatory problems, among others. This work includes a proposal that initiates the study and development of new biomaterials or vehicles with therapeutic application. The nanomolecular interaction of the organic extract of a plant (EOV) Distictis buccinatoria (dc) with different materials inert supports of inorganic type (bentonite, gel) determining their and combined anti-inflammatory activity is studied individually [1] [2]. The importance of the characterization of biomaterials by scanning electron microscopy (SEM) is ability to analyze the structure on the surface of materials (organic, inorganic and biological) in the micro and nanometrics levels in order to correlate it with the sample surface properties such as roughness, interfacial phenomena, etc. With this technique we can also perform the chemical analysis at different levels (micro and nano) for information on the nature and composition of the materials [3] [4]. The biomaterial shows that higher anti-inflammatory activity is to be generated through the combination of EOV-gel, the nanostructure interaction SEM shows integrated particles agglome-rated form and porous due to the presence of EOV and some flat areas indicated the gel preponderance situation generated by the low interaction between materials of organic type and polar type (gel).

关键词： Biomaterials nanomolecular Anti-Inflamatory Vehicles

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Retroperitoneal epithelioid sarcoma: A case report

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World Journal of Gastrointestinal Endoscopy 2017年第12期9卷 579-582页

作者： JoséA Coronado Migueláchávez Martín A Manrique Jony Cerna Ana L Trejo Division of Gastrointestinal Endoscopy Hospital Juarez de Mexico Division of Anatomic Pahology Hospital Juarez de Mexico

Epithelioid sarcoma(ES), a mesenchymatous malign neoformation, is often diagnosed in later stages and associated with high recurrence index, metastasis and mortality. We report a case of a 65 years old male, with history of abdominal pain and upper gastrointestinal bleeding. Endoscopy demonstrated a posterior duodenal wall perforation communicating with a solid retroperitoneal neoformation. Endoscopic biopsy was performed, with a final report of ES. The patient was submitted for surgical palliation due to the tumor's unresectability. Retroperitoneal ES is an extremely rare condition with limited reports in the literature where guidelines for its optimal treatment are not well established.

关键词： Epithelioid sarcoma Retroperitoneal Mesenchymatous neoformation Duodenal perforation Endoscopy

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Penetrating neck Trauma in a 4-Year-Old child

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Case Reports in Clinical Medicine 2015年第4期4卷 145-150页

作者： V. Lambropoulos I. Lazaridis n. Melas ch. Kepertis K. Anastasiades Clinic of Pediatric Surgery Aristotle University of Thessaloniki G. Hospital Papageorgiou Thessaloniki Greece Surgical Clinic Aristotle University of Thessaloniki G. Hospital Papageorgiou Thessaloniki Greece

Penetrating neck injuries are uncommon in children and a post traumatic common carotid artery to internal jugular vein fistula rarely occurs. We present one case of a 4-year-old girl with a penetrating injury from flying glass fragments in the midportion of the neck, caused by an explosion in a military warehouse. She was referred to our facility upon a request of a hospital of a neighbour country, two days after sustaining a penetrating cervical trauma. The presentation, diagnostic procedures and surgical management of this very rare injury are discussed. no neck penetrating trauma should be underestimated and a selective surgical intervention based on clinical examination and investigation tests findings is associated with good long-term outcomes.

关键词： neck Trauma Carotid-Jugular Fistula children Diagnosis Surgery

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对《消费经济》的展望与期望——庆祝《消费经济》创刊20周年

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消费经济 2006年第2期22卷 3-4页

作者：何炼成西北大学经济管理学院

在我国著名消费经济学家尹世杰教授的亲手领导和指导下，《消费经济》杂志迎来了20周年华诞，可喜可贺。作为贵刊的忠实读者与作者，谨对贵刊的创建者和指导者表示崇高的敬意，并对贵刊全体工作人员表示诚挚的感谢。

关键词：消费经济创刊20周年期望展望经济学家工作人员尹世杰指导者

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基于人均GDP的上海房地需求分析

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消费经济 2005年第2期21卷 52-54页

作者：陈鹏程复旦大学管理学院上海200433

目前上海市房地产需求处于数量和质量并重的发展阶段,本文以上海市人均GDP为基础,采用上海市1985-2003年的历史数据,建立了上海市人均住房面积与人均GDP的回归模型,利用这一回归模型对上海市2020年前的主要年份住房需求进行了预测。

关键词：上海房地产业人均GDP 房地产需求房地产市场

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论消费者权益案中的举证责任配置

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消费经济 2005年第2期21卷 72-74页

作者：谌小永湖南省怀化市委党校湖南怀化418008

与商品生产经营者相比,消费者在保护消费者权益过程中发生的经济关系中处于弱势地位,因而在侵权诉讼中配置举证责任时应向消费者倾斜,即消费者只需负责举证受损害的事实证据,其他举证责任则应由商品生产经营者负责。

关键词：消费者权益举证责任配置《消费者权益保护法》中国维权工作侵权行为产品质量

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Research on a Dispersed networked CAD/CAM System of Motorcycle

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厦门大学学报（自然科学版） 2002年第S1期41卷 167-168页

作者： WAnG Xian-kun (Dept. of Mech.nical Engineering, Fuzhou University, Fuzhou 350002, ch ina)

In order to improve competitive ability of market, mo torcycle enterprises, special the small and middle sized ones must use IT to org anize social resource and adopt effective production mode, namely the dispersed networked design and manufacturing (DnDM), which was put forward and proved to b e one of vitality production modes in recent years. In responding to the new pro duction mode of VMCE, a dispersed networked CAD/CAM system (DnCADMS) of motorcyc le products should be developed. The objective of this paper is to investigate a new design and manufacturing mode and technical environment of motorcycle produ ction based on the concept of the DnDM for the small and meddle sized motorcycle enterprises. Because there are various CAx software systems, including differen t kinds of isolated CD, CAD, CAE, CAPP, CAM, PDM, and so on, are used at differe nt stages of the life period of motorcycle products under heterogeneous environm ents, to build a DnCADMS of motorcycle with high performance, some key issues, n amely the architecture of the DnCADMS, the integration of the isolated CAx softw are systems (CAxs), the data communication and exch.nge between these isolated s ystems and the data share problem under the dispersed heterogeneous database env ironment, should be solved well. For this, the idea we propose is the combinatio n of Web, CORBA, STEP and Java, which provides an effective mech.nism to support the integration of isolated CAxs, and support communication and interoperabilit y among CAx systems. Each isolated CAx has been encapsulated respectively by a c ontainer, which is implemented by the ORBs and the IDL of the COBRA technology s tandard, and managed by the application index server. Each container is connecte d with the others by a local network or intranet/Extranet/internet and communica tes through network. For exch.nging design and manufacturing information and kno wledge via a local network or the Internet, a commmerical product data translato r has

关键词： dispersed networked CAD/CAM PDM motorcycle We b CORBA

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An Assessment of Water Quality Parameters at the Cerrillos Reservoir, Ponce, Puerto Rico in the Aftermath of Hurricane Maria

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Journal of Water Resource and Protection 2022年第1期14卷 35-49页

作者： Yashira Marie Sánchez-Colón Javier Alejandro chévere-Del Río nichole Marie Sánchez-Guzmán Fred charles Schaffner Public Health Program Ponce Health Sciences University Ponce Puerto Rico Puerto Rico Department of Health San Juan Puerto Rico School of Science and Technology Universidad Ana G Méndez Gurabo Campus Gurabo Puerto Rico

Maintaining the water quality of lakes and reservoirs is part of the 2030 Agenda for Sustainable Development, an initiative promoted by the United nations, including anthropogenic and natural factors that may influence water quality. The water reservoirs of Puerto Rico were built in watersheds to provide runoff control and for primary uses. The Cerrillos Reservoir is one of the largest water reservoirs in southern Puerto Rico, and is used as a source of potable water and for recreational activities. After hurricane Maria, in September 2017, many communities were without public water service and have obtained their drinking water from local rivers or their tributaries, without filtration or purification treatment. This research explored the physical-chemical parameters of Cerrillos Reservoir’s surface water from May 2018 to January 2019. The objective of the present study is to assess seasonal variations in surface water quality with respect to physical (temperature, turbidity, and conductivity), chemical (nutrient concentrations: (Phosphorus (P) (Soluble Reactive Phosphorus, phosphate, or orthophosphate) and nitrogen (n) (nitrate, nitrite, and ammonia)), pH, and dissolved oxygen), and biological (total coliforms and Escherichia coli) parameters. Results suggest that Cerrillos Reservoir did not exceed the parameters of temperature, turbidity, conductivity, pH and DO, established by the Puerto Rico Department of natural and Environmental Resources (PRDnER). The reservoir showed a stable trophic state in relation to inorganic phosphorus and nitrogen as n and P concentrations did not increase sufficiently to disrupt this ecosystem. However, total coliforms exceeded the maximum parameter (23 MPn/100mL - 994 MPn/100mL) established for the Puerto Rico Department of natural and Environmental Resources and are likely to be the results of the disruption caused by hurricane Maria.

关键词： Cerrillos Reservoir Water Quality Puerto Rico Post Hurricane Maria

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