WorldWideScience

Sample records for period 1997-2002 mechanical

  1. The frequency of resistance to antibiotics of most frequently isolated bacteria from blood cultures during the period 1997-2002

    Directory of Open Access Journals (Sweden)

    Mirović Veljko

    2004-01-01

    Full Text Available The aim of this study was to determine the frequency of resistance to antibiotics of the most frequently isolated bacteria from blood cultures of hospitalized patients during the period 1997-2002. The resistance to antibiotics was determined by disk diffusion method according to National Committee for Clinical Laboratory Standards procedures. The majority of staphylococci isolates were resistant to methicillin, and the proportion of methicillin-resistant Staphylococcus aureus was stable (76.8-81.6%, during the follow-up period. None of the staphylococci isolates were resistant to vancomycin, but there was a very high incidence of high-level resistance of enterococci to aminoglycosides (47.2-72.2%. In 1998, only one strain among enterococci was resistant to vancomycin (Enterococcus faecium, VanA fenotype. Enterococcus spp isolates expressed variable frequency of resistance to ampicillin (15-40.1% during the follow-up period. Among Enterobacteriaceae there were no isolates resistant to imipenem, but dramatic increase of the resistance to ceftriaxone was found from 35.9% in 1997 to 95.9% in 2002 (p<0.001. Extended spectrum beta-lactamases production was found in all the species of enterobacteria isolates. Resistance to imipenem was observed in Acinetobacter spp isolates in 2002 for the first time. Pseudomonas spp isolates expressed high and very variable resistance to all antibiotics tested during the follow-up period.

  2. Institutional plan. FY 1997-2002

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    The FY 1997-2002 Institutional Plan provides an overview of the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) mission, strategic plan, core business areas, critical success factors, and the resource requirements to fulfill its mission in support of national needs in fundamental science and technology, energy resources, and environmental quality. Of particular significance this year is the role of computing sciences in supporting a broad range of research activities, at Berkeley Lab in particular and throughout the entire Department of Energy system in general. The Institutional Plan is a management report for integration with the Department of Energy`s mission and programs and is an element of Department of Energy`s strategic management planning activities, developed through an annual planning process. The plan identifies technical and administrative directions in the context of the national energy policy and research needs and the Department of Energy`s program planning initiatives.

  3. Hepatitis B vaccination of male neonates and autism diagnosis, NHIS 1997-2002.

    Science.gov (United States)

    Gallagher, Carolyn M; Goodman, Melody S

    2010-01-01

    Universal hepatitis B vaccination was recommended for U.S. newborns in 1991; however, safety findings are mixed. The association between hepatitis B vaccination of male neonates and parental report of autism diagnosis was determined. This cross-sectional study used weighted probability samples obtained from National Health Interview Survey 1997-2002 data sets. Vaccination status was determined from the vaccination record. Logistic regression was used to estimate the odds for autism diagnosis associated with neonatal hepatitis B vaccination among boys age 3-17 years, born before 1999, adjusted for race, maternal education, and two-parent household. Boys vaccinated as neonates had threefold greater odds for autism diagnosis compared to boys never vaccinated or vaccinated after the first month of life. Non-Hispanic white boys were 64% less likely to have autism diagnosis relative to nonwhite boys. Findings suggest that U.S. male neonates vaccinated with the hepatitis B vaccine prior to 1999 (from vaccination record) had a threefold higher risk for parental report of autism diagnosis compared to boys not vaccinated as neonates during that same time period. Nonwhite boys bore a greater risk.

  4. Synthesis report regarding the Forest Industry Program 1997-2002[Energy research]; Skogsindustriell energiforskning syntesrapport 1997-2002

    Energy Technology Data Exchange (ETDEWEB)

    Kjoerk, Anders; Olle, Nystroem

    2003-07-01

    This synthesis report commissioned by the Thermal Engineering Research Institute (Varmeforsk) constitutes a summary of the Forest Industry Program up to and including turn of the year 2002/2003. According to the assignment the resulting reports of the program has specifically been related to the present and expected EU-directives and, as a base for interpretation, national rules and regulations of relevance to the programme. Also there is a discussion, from a broad perspective, of the value and usefulness of these reports as well as of how the resources should be spent and prioritised in a coming program. As a basis for the analysis a survey of the program directions and the aims descriptions for the periods 97-98, 99-00 and 01-02 has been carried out. Throughout the three periods there is a tendency going from specific areas of interest to a more general approach which in the last program period has resulted in program directions emphasizing utilization of energy, energy integration and coordination with industry and enterprises outside the forest industry where it applies. A survey of the relevant EU-directives has been carried out. A division was made between directives related to legislation overall, permits related to combustion, operation of combustion plants and landfilling of refuse. In total 26 reports have been summarized and evaluated. They include some, which, at the time of finishing the present report, had not yet been published. The overall result has been synthesized in a discussion covering contents, aims, fulfillment and value of the reports. The work have been structured and presented based on some main activity areas that have been possible to identify from the program directions and policy statements, they are: combustion efficiency, improved energy utilization and novel concepts. Some reports, which have not been possible to arrange under these headings and furthermore are difficult to associate with the main areas defined are covered under a

  5. Rocky Mountain spotted fever in the United States, 1997-2002.

    Science.gov (United States)

    Chapman, Alice S; Murphy, Staci M; Demma, Linda J; Holman, Robert C; Curns, Aaron T; McQuiston, Jennifer H; Krebs, John W; Swerdlow, David L

    2006-01-01

    Rocky Mountain spotted fever (RMSF) is the most commonly reported fatal tick-borne disease in the United States. During 1997-2002, 3,649 cases of RMSF were reported to the Centers for Disease Control and Prevention via the National Electronic Telecommunications System for Surveillance; 2,589 case report forms, providing supplemental information, were also submitted. The average annual RMSF incidence during 1997-2002 was 2.2 cases/million persons. The annual incidence increased during 1997-2002 to a rate of 3.8 cases/million persons in 2002. The incidence was lowest among persons aged<5 and 10-29 years, and highest among adults aged 60-69 years. The overall case-fatality rate was 1.4%; the rate peaked in 1998 at 2.9% and declined to 0.7% in 2001 and 2002. Children<5 years of age had a case-fatality rate (5%) that was significantly greater than the rates for age groups<60 years of age, except for that for 40-49 years of age. Continued national surveillance is needed to assess the effectiveness of prevention efforts and early treatment in decreasing severe morbidity and mortality associated with RMSF.

  6. Geometric mechanics of periodic pleated origami.

    Science.gov (United States)

    Wei, Z Y; Guo, Z V; Dudte, L; Liang, H Y; Mahadevan, L

    2013-05-24

    Origami structures are mechanical metamaterials with properties that arise almost exclusively from the geometry of the constituent folds and the constraint of piecewise isometric deformations. Here we characterize the geometry and planar and nonplanar effective elastic response of a simple periodically folded Miura-ori structure, which is composed of identical unit cells of mountain and valley folds with four-coordinated ridges, defined completely by two angles and two lengths. We show that the in-plane and out-of-plane Poisson's ratios are equal in magnitude, but opposite in sign, independent of material properties. Furthermore, we show that effective bending stiffness of the unit cell is singular, allowing us to characterize the two-dimensional deformation of a plate in terms of a one-dimensional theory. Finally, we solve the inverse design problem of determining the geometric parameters for the optimal geometric and mechanical response of these extreme structures.

  7. El gasto en la atención y la prevención del VIH/SIDA en México: tendencias y estimaciones 1997-2002 HIV/AIDS care and prevention expenditures in Mexico: trends and estimations 1997-2002

    Directory of Open Access Journals (Sweden)

    Carlos Magis-Rodríguez

    2005-10-01

    Full Text Available OBJETIVO: Presentar un análisis de la tendencia seguida por el gasto ejercido en el combate de la epidemia de VIH/SIDA en México durante el periodo 1997-2002, contrastando el gasto y la distribución actual con las proyecciones internacionales y la situación imperante en otros países de la región. MATERIAL Y MÉTODOS: A partir de 1997, y durante tres bienios consecutivos, se ha desarrollado el análisis contable, sistematizado y exhaustivo de los flujos de financiamiento y gasto orientados al suministro de bienes y servicios relacionados con la atención y la prevención del VIH/SIDA, ejercicio denominado Cuentas Nacionales de SIDA. RESULTADOS: Se observa un incremento real y sostenido en el gasto total destinado al combate de la epidemia, estimado en 143% y ejercido en diferentes rubros, pero particularmente en el gasto en medicamentos antirretrovirales. No obstante, comparado con otros países de la región, el gasto mexicano en VIH/SIDA tiene un menor sesgo en cuanto a la asignación entre prevención y tratamiento. DISCUSIÓN: El gobierno mexicano se ha comprometido a garantizar el acceso universal al tratamiento antirretroviral para los pacientes con VIH/SIDA que lo necesiten y, al mismo tiempo, a mantener e incluso aumentar los esfuerzos en prevención. Estas actividades demandan incrementos en los recursos destinados para combatir la epidemia, por lo que es importante dar seguimiento a la eficiencia con que se estén utilizando los mismos, de forma que se pueda mejorar su asignación y focalización.OBJECITVE: This paper first presents the trend of HIV/AIDS expenditures in Mexico between 1997 and 2002. It then compares the allocation and magnitude of such expenditures within the international context and, in particular, how other countries in the region are allocating HIV/AIDS resources. MATERIAL AND METHODS: Since 1997, Mexico has developed and been utilizing a method for systematically and comprehensively analyze national resource

  8. Response to various periods of mechanical stimuli in Physarum plasmodium

    International Nuclear Information System (INIS)

    Umedachi, Takuya; Ito, Kentaro; Kobayashi, Ryo; Ishiguro, Akio; Nakagaki, Toshiyuki

    2017-01-01

    Response to mechanical stimuli is a fundamental and critical ability for living cells to survive in hazardous conditions or to form adaptive and functional structures against force(s) from the environment. Although this ability has been extensively studied by molecular biology strategies, it is also important to investigate the ability from the viewpoint of biological rhythm phenomena so as to reveal the mechanisms that underlie these phenomena. Here, we use the plasmodium of the true slime mold Physarum polycephalum as the experimental system for investigating this ability. The plasmodium was repetitively stretched for various periods during which its locomotion speed was observed. Since the plasmodium has inherent oscillation cycles of protoplasmic streaming and thickness variation, how the plasmodium responds to various periods of external stretching stimuli can shed light on the other biological rhythm phenomena. The experimental results show that the plasmodium exhibits response to periodic mechanical stimulation and changes its locomotion speed depending on the period of the stretching stimuli. (paper)

  9. Intrinsic periodicity: the forgotten lesson of quantum mechanics

    International Nuclear Information System (INIS)

    Dolce, Donatello

    2013-01-01

    Wave-particle duality, together with the concept of elementary particles, was introduced by de Broglie in terms of intrinsically periodic phenomena. However, after nearly 90 years, the physical origin of such undulatory mechanics remains unrevealed. We propose a natural realization of the de Broglie periodic phenomenon in terms of harmonic vibrational modes associated to space-time periodicities. In this way we find that, similarly to a vibrating string or a particle in a box, the intrinsic recurrence imposed as a constraint to elementary particles represents a fully consistent quantization condition. The resulting cyclic dynamics formally match ordinary relativistic Quantum Mechanics in both the canonical and Feynman formulations. Interactions are introduced in a geometrodynamical way, similarly to general relativity, by simply considering that variations of kinematical state can be equivalently described in terms of modulations of space-time recurrences, as known from undulatory mechanics. We present this novel quantization prescription from an historical prospective.

  10. Trajetórias de um grupo interinstitucional em um programa de formação de educadores ambientais no estado do Paraná (1997-2002 Trajectories of an inter-institutional group in a formation process of environmental teachers in the state of Paraná (1997-2002

    Directory of Open Access Journals (Sweden)

    Liana Márcia Justen

    2006-06-01

    Full Text Available A importância do registro de experiências de formação de educadores ambientais motivou a realização desta pesquisa sobre a trajetória de atuação de um grupo de professores e técnicos ambientais, em um programa desenvolvido no Estado do Paraná (1997-2002. A integração de propostas governamentais de Educação Ambiental (EA, desenvolvidas nas redes públicas de ensino e comunidades, visava a implementação dos programas ambientais coordenados pelo governo do estado, em parceria com os municípios, nas gestões 1995/1998 e 1999/2002. Para efetivar ações conjuntas entre as Secretarias de Estado de Educação e do Meio Ambiente e Recursos Hídricos, foram criadas equipes interinstitucionais de EA compostas por professores e técnicos ambientais. A partir das percepções dos dois grupos de participantes do processo sobre suas interações afetivas e profissionais, diferenças conceituais e efetividade do programa, procuraram-se sistematizar aspectos relevantes desse singular processo de formação de educadores ambientais, promovido na esfera política e administrativa governamental, reconhecendo indicativos básicos para a atuação de equipes interinstitucionais e subsidiando a reflexão sobre processos formativos em EA. A atuação conjunta de professores e técnicos ambientais consistiu em uma experiência no terreno da diversidade, possibilitando-lhes o reconhecimento da outridade, o exercício do diálogo entre saberes e fazeres, a convivência com o dissenso e a busca de soluções inclusivas para as questões ambientais - princípios básicos da EA.The importance of recording education experiences of environmental teachers has motivated this research about the performance of a group of teachers and environmental technicians, in a program developed in the State of Paraná (1997-2002. The integration of government proposals of EE (Environmental Education developed at public schools and communities, had the objective of

  11. Self-isospectral periodic potentials and supersymmetric quantum mechanics

    International Nuclear Information System (INIS)

    Dunne, G.; Feinberg, J.

    1998-01-01

    We discuss supersymmetric quantum mechanical models with periodic potentials. The important new feature is that it is possible for both isospectral potentials to support zero modes, in contrast with the standard nonperiodic case where either one or neither (but not both) of the isospectral pair has a zero mode. Thus it is possible to have supersymmetry unbroken and yet also have a vanishing Witten index. We present some explicit exactly soluble examples for which the isospectral potentials have identical band spectra, and which are open-quotes self-isospectralclose quotes in the sense that the potentials have identical shape, but are translated by one half-period relative to one another. copyright 1997 The American Physical Society

  12. The wave attenuation mechanism of the periodic local resonant metamaterial

    Science.gov (United States)

    Chang, I.-Ling; Liang, Zhen-Xian; Kao, Hao-Wei; Chang, Shih-Hsiang; Yang, Chih-Ying

    2018-01-01

    This research discusses the wave propagation behavior and attenuation mechanism of the elastic metamaterial with locally resonant sub-structure. The dispersion relation of the single resonance system, i.e., periodic spring mass system with sub-structure, could be derived based on lattice dynamics and the band gap could be easily identified. The dynamically equivalent properties, i.e., mass and elastic property, of the single resonance system are derived and found to be frequency dependent. Negative effective properties are found in the vicinity of the local resonance. It is examined whether the band gap always coincides with the frequency range of negative effective properties. The wave attenuation mechanism and the characteristic dynamic behavior of the elastic metamaterial are also studied from the energy point of view. From the analysis, it is clarified that the coupled Bragg-resonance band gap is much wider than the narrow-banded local resonance and the corresponding effective material properties at band gap could be either positive or negative. However, the band gap is totally overlapping with the frequency range of negative effective properties for the metamaterial with band gap purely caused by local resonance. The presented analysis can be extended to other forms of elastic metamaterials involving periodic resonator structures.

  13. Institutional plan. Fiscal Year 1997--2002

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    Sandia National Laboratories is operated for the United States Department of Energy by a subsidiary of Lockheed Martin Corporation. National security programs and defense-related environmental programs for DOE comprise 65 percent of Sandia`s work. We are the DOE Defense Programs laboratory responsible for engineering development of all US nuclear weapons and for systems integration of the nuclear weapons with their delivery vehicles. Our responsibilities include design, certification, and assessment of the nonnuclear subsystems of nuclear weapons; safety, security, reliability, and use control; issues associated with production and dismantlement of nuclear weapons; surveillance and support of weapons in the stockpile; and work in nuclear intelligence, nonproliferation, and treaty verification technologies. Sandia is a multiprogram laboratory. Ten percent of our work supports DOE missions in energy science, research, and development. When appropriate, we also perform work for other government agencies, particularly the Department of Defense, in programs where unique competencies built our mission responsibilities can add value. This report discusses the activities of these responsibilities at the Sandia National Laboratories.

  14. Institutional plan. Fiscal year, 1997--2002

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    The Institutional Plan is the culmination of Argonne`s annual planning cycle. The document outlines what Argonne National Laboratory (ANL) regards as the optimal development of programs and resources in the context of national research and development needs, the missions of the Department of Energy and Argonne National Laboratory, and pertinent resource constraints. It is the product of ANL`s internal planning process and extensive discussions with DOE managers. Strategic planning is important for all of Argonne`s programs, and coordination of planning for the entire institution is crucial. This Institutional Plan will increasingly reflect the planning initiatives that have recently been implemented.

  15. Suppressing non-periodically repeating disturbances in mechanical servo systems

    NARCIS (Netherlands)

    Tousain, R.L.; Boissy, J.C.; Norg, M.L.; Steinbuch, M.; Bosgra, O.H.

    1998-01-01

    Non-periodically repeating (NPR) disturbances are fixed-shape disturbances that occur randomly in time. We can provide a control system with the capability to suppress this type of disturbance by adding in parallel to the input of the nominal feedback controller a learning look-up-table based

  16. Mechanical characterisation of a periodic auxetic structure produced by SEBM

    Energy Technology Data Exchange (ETDEWEB)

    Schwerdtfeger, J. [Institute of Advanced Materials and Processes (ZMP), University of Erlangen-Nuernberg, Dr.-Mack-Str. 81, 90762 Fuerth (Germany); Schury, F.; Stingl, M.; Wein, F. [Institute of Applied Mathematics 2 (AM2), University of Erlangen-Nuernberg, Martensstr. 3, 91058 Erlangen (Germany); Singer, R.F.; Koerner, C. [Institute of Materials Science and Technology (WTM), University of Erlangen-Nuernberg, Martensstr. 5, 91058 Erlangen (Germany)

    2012-07-15

    We present a thorough investigation of the mechanical behaviour of a non-stochastic cellular auxetic structure. A combination of experimental and numerical methods is used to gain a deeper understanding of the mechanical behaviour and its dependence on the geometric properties of the cellular structure. The experimental samples are built from Ti-6Al-4V using selective electron beam melting, an additive manufacturing process giving the possibility to vary the geometry of the structure in a highly controlled manner. The use of finite element simulations and mathematical homogenisation allows us also to investigate off-axis properties of the cellular material. This leads to a more comprehensive understanding of the mechanical behaviour of the auxetics. Ultimately, the gained knowledge can be used to tailor auxetic materials to specific applications. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Mechanical Engineering Department technical abstracts for the period January-June 1985

    International Nuclear Information System (INIS)

    Woo, H.H.

    1986-01-01

    This document contains the abstracts from 116 reports produced by the Mechanical Engineering Department of the Lawrence Livermore National Laboratory during the period January - June, 1985. The Mechanical Engineering Department is reponsible for the design, analysis, fabrication, testing, and field installation of all mechanical components and systems required by Defence Systems, Lasers, Magnetic Fusion Energy, Physics, and Biomedical and Environmental Research. Similar support is provided to the Chemistry and Computation Departments. Keyword, author, and report-number indices are included

  18. Kinetics and mechanism of oxidation of tellurium (IV) by periodate in alkaline medium

    International Nuclear Information System (INIS)

    Srinivas, K.; Vani, P.; Dikshitulu, L.S.A.

    1995-01-01

    Detailed kinetic study of the oxidation of tellurium (IV) by periodate in alkaline medium has been carried out to compare the mechanisms of oxidation in the acid and alkaline media. It is interesting to note that the rate step involves a two-electron transfer from tellurium (IV) to periodate in alkaline medium although the kinetic pattern is somewhat different from that in the acid medium. 7 refs., 1 tab

  19. Detecting method for crude oil price fluctuation mechanism under different periodic time series

    International Nuclear Information System (INIS)

    Gao, Xiangyun; Fang, Wei; An, Feng; Wang, Yue

    2017-01-01

    Highlights: • We proposed the concept of autoregressive modes to indicate the fluctuation patterns. • We constructed transmission networks for studying the fluctuation mechanism. • There are different fluctuation mechanism under different periodic time series. • Only a few types of autoregressive modes control the fluctuations in crude oil price. • There are cluster effects during the fluctuation mechanism of autoregressive modes. - Abstract: Current existing literatures can characterize the long-term fluctuation of crude oil price time series, however, it is difficult to detect the fluctuation mechanism specifically under short term. Because each fluctuation pattern for one short period contained in a long-term crude oil price time series have dynamic characteristics of diversity; in other words, there exhibit various fluctuation patterns in different short periods and transmit to each other, which reflects the reputedly complicate and chaotic oil market. Thus, we proposed an incorporated method to detect the fluctuation mechanism, which is the evolution of the different fluctuation patterns over time from the complex network perspective. We divided crude oil price time series into segments using sliding time windows, and defined autoregressive modes based on regression models to indicate the fluctuation patterns of each segment. Hence, the transmissions between different types of autoregressive modes over time form a transmission network that contains rich dynamic information. We then capture transmission characteristics of autoregressive modes under different periodic time series through the structure features of the transmission networks. The results indicate that there are various autoregressive modes with significantly different statistical characteristics under different periodic time series. However, only a few types of autoregressive modes and transmission patterns play a major role in the fluctuation mechanism of the crude oil price, and these

  20. A new type of sandwich panel with periodic cellular metal cores and its mechanical performances

    International Nuclear Information System (INIS)

    Lim, Chae-Hong; Jeon, Insu; Kang, Ki-Ju

    2009-01-01

    Many studies have been performed on the mechanical properties and optimization of truss PCMs (periodic cellular metals), but those on the fabrication process, which is one of key factors determining the survivability of PCMs in the market, have been relatively limited. This study introduces a new idea on the fabrication of quasi Kagome truss cored sandwich panels, which is based on the expanded-metal process. And the mechanical behavior of the sandwich panels is to be evaluated. The mechanical strengths and failure mechanisms under compression and bending load are estimated based on elementary mechanics of materials, and the optimal design is derived. Its validity is proved by comparison with the results of experiments. The results showed that the new idea is promising with respect to all three requirements, i.e., the morphology, fabrication cost, and raw materials. The simple mechanical analysis was sufficiently effective and accurate for estimating the performance and failure mode of the sandwich panels. In the experiments, sandwich panel specimens of three different designs were compared in their bending behaviors to demonstrate sensitivity of geometric parameters. Namely, although all the designs had little difference in their load capacity-per-weight, the failure mechanisms and the behaviors after a peak load were totally different.

  1. Computation of Quasi-Periodic Normally Hyperbolic Invariant Tori: Algorithms, Numerical Explorations and Mechanisms of Breakdown

    Science.gov (United States)

    Canadell, Marta; Haro, Àlex

    2017-12-01

    We present several algorithms for computing normally hyperbolic invariant tori carrying quasi-periodic motion of a fixed frequency in families of dynamical systems. The algorithms are based on a KAM scheme presented in Canadell and Haro (J Nonlinear Sci, 2016. doi: 10.1007/s00332-017-9389-y), to find the parameterization of the torus with prescribed dynamics by detuning parameters of the model. The algorithms use different hyperbolicity and reducibility properties and, in particular, compute also the invariant bundles and Floquet transformations. We implement these methods in several 2-parameter families of dynamical systems, to compute quasi-periodic arcs, that is, the parameters for which 1D normally hyperbolic invariant tori with a given fixed frequency do exist. The implementation lets us to perform the continuations up to the tip of the quasi-periodic arcs, for which the invariant curves break down. Three different mechanisms of breakdown are analyzed, using several observables, leading to several conjectures.

  2. Mechanism design of reverse auction on concession period and generalized quality for PPP projects

    Institute of Scientific and Technical Information of China (English)

    Xianjia WANG; Shiwei WU

    2017-01-01

    Reverse auctions of PPP projects usually require the bid to specify several characteristics of quality and the concession period to be fulfilled.This paper sets up a summary function of generalized quality,which contributes to reducing the dimensions of information.Thus,the multidimensional reverse auction model of a PPP project can be replaced by a two-dimensional direct mechanism based on the concession period and the generalized quality.Based on the theory of the revelation principle,the feasibility conditions,equilibrium solution and generalized quality requirements of such a mechanism,considering the influence of a variable investment structure are described.Moreover,two feasible multidimensional reverse auctions for implementing such a direct mechanism:Adjusting the scoring function and establishing a special reverse auction rule are built.The analysis shows that in these types of reverse auctions,optimal allocation can be achieved,the social benefit under the incomplete information will be maximized,and the private sector with the highest integrated management level wins the bid.In such a direct mechanism,the investment and financial pressure of the public sector can be reduced.

  3. Energy storage and dispersion of surface acoustic waves trapped in a periodic array of mechanical resonators

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    It has been shown previously that surface acoustic waves can be efficiently trapped and slowed by steep ridges on a piezoelectric substrate, giving rise to two families of shear-horizontal and vertically polarized surface waves. The mechanisms of energy storage and dispersion are explored by using...... the finite element method to model surface acoustic waves generated by high aspect ratio electrodes. A periodic model is proposed including a perfectly matched layer to simulate radiation conditions away from the sources, from which the modal distributions are found. The ratio of the mechanical energy...... confined to the electrode as compared to the total mechanical energy is calculated and is found to be increasing for increasing aspect ratio and to tend to a definite limit for the two families of surface waves. This observation is in support of the interpretation that high aspect ratio electrodes act...

  4. Proteomics approach reveals mechanism underlying susceptibility of loquat fruit to sunburn during color changing period.

    Science.gov (United States)

    Jiang, Ji-Mou; Lin, Yong-Xiang; Chen, Yi-Yong; Deng, Chao-Jun; Gong, Hui-Wen; Xu, Qi-Zhi; Zheng, Shao-Quan; Chen, Wei

    2015-06-01

    The objective of this work was to investigate why loquat fruit peels are more sensitive to high temperature and strong sunlight, making them highly susceptible to sunburn, during the color changing period (CCP). Two dimensional gel electrophoresis (2-DE) of the fruit peel proteins was performed over three developmental periods, namely green fruit period (GFP), color changing period and yellow ripening period (YRP). Fifty-five protein spots with at least 2-fold differences in abundance were successfully identified by MALDI-TOF-TOF/MS. The identified proteins were divided into categories related to heat-shock response, stress response and defense, energy metabolism, photosynthesis and protein biosynthesis. The results showed that expression of proteins related to anaerobic respiration and photorespiration were increased while the proteins related to ROS scavenging, polyamine biosynthesis, defense pathogens and photosynthesis were decreased during CCP under heat stress. Our findings provide new insights into the molecular mechanism of loquat fruit susceptible to sunburn during CCP. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Mechanical low-frequency filter via modes separation in 3D periodic structures

    Science.gov (United States)

    D'Alessandro, L.; Belloni, E.; Ardito, R.; Braghin, F.; Corigliano, A.

    2017-12-01

    This work presents a strategy to design three-dimensional elastic periodic structures endowed with complete bandgaps, the first of which is ultra-wide, where the top limits of the first two bandgaps are overstepped in terms of wave transmission in the finite structure. Thus, subsequent bandgaps are merged, approaching the behaviour of a three-dimensional low-pass mechanical filter. This result relies on a proper organization of the modal characteristics, and it is validated by performing numerical and analytical calculations over the unit cell. A prototype of the analysed layout, made of Nylon by means of additive manufacturing, is experimentally tested to assess the transmission spectrum of the finite structure, obtaining good agreement with numerical predictions. The presented strategy paves the way for the development of a class of periodic structures to be used in robust and reliable wave attenuation over a wide frequency band.

  6. Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

    Science.gov (United States)

    Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-05-01

    Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

  7. The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

    International Nuclear Information System (INIS)

    Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen

    2013-01-01

    Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage

  8. The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2013-06-15

    Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage.

  9. Mechanism for boundary crises in quasiperiodically forced period-doubling systems

    International Nuclear Information System (INIS)

    Kim, Sang-Yoon; Lim, Woochang

    2005-01-01

    We investigate the mechanism for boundary crises in the quasiperiodically forced logistic map which is a representative model for quasiperiodically forced period-doubling systems. For small quasiperiodic forcing ε, a chaotic attractor disappears suddenly via a 'standard' boundary crisis when it collides with the smooth unstable torus. However, when passing a threshold value of ε, a basin boundary metamorphosis occurs, and then the smooth unstable torus is no longer accessible from the interior of the basin of the attractor. For this case, using the rational approximations to the quasiperiodic forcing, it is shown that a nonchaotic attractor (smooth torus or strange nonchaotic attractor) as well as a chaotic attractor is destroyed abruptly through a new type of boundary crisis when it collides with an invariant 'ring-shaped' unstable set which has no counterpart in the unforced case

  10. Mechanism for boundary crises in quasiperiodically forced period-doubling systems

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang-Yoon [Department of Physics, Kangwon National University, Chunchon, Kangwon-Do 200-701 (Korea, Republic of)]. E-mail: sykim@kangwon.ac.kr; Lim, Woochang [Department of Physics, Kangwon National University, Chunchon, Kangwon-Do 200-701 (Korea, Republic of)]. E-mail: wclim@kwnu.kangwon.ac.kr

    2005-01-10

    We investigate the mechanism for boundary crises in the quasiperiodically forced logistic map which is a representative model for quasiperiodically forced period-doubling systems. For small quasiperiodic forcing {epsilon}, a chaotic attractor disappears suddenly via a 'standard' boundary crisis when it collides with the smooth unstable torus. However, when passing a threshold value of {epsilon}, a basin boundary metamorphosis occurs, and then the smooth unstable torus is no longer accessible from the interior of the basin of the attractor. For this case, using the rational approximations to the quasiperiodic forcing, it is shown that a nonchaotic attractor (smooth torus or strange nonchaotic attractor) as well as a chaotic attractor is destroyed abruptly through a new type of boundary crisis when it collides with an invariant 'ring-shaped' unstable set which has no counterpart in the unforced case.

  11. Evolution and mechanism of the periodical structures formed on Ti plate under femtosecond laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong, E-mail: ld20501@126.com; Chen, Chuansong, E-mail: chencs@sdnu.edu.cn; Man, Baoyuan, E-mail: byman@sdnu.edu.cn; Meng, Xue; Sun, Yanna, E-mail: sunyuannaa@163.com; Li, Feifei

    2016-08-15

    Highlights: • Investigate the evolution and succession of three types of fs-laser induced periodic surface structures (FLIPSSs). • Achieve the laser processing window of each type of the FLIPSS. • Explain the formation and evolvement of the ripple structure in the respective of surface plasma wave (SPW). • Ascribe the interaction between the transmitted laser and the reflected laser at the two surfaces of the biconvex lens to the formation of ring structure. - Abstract: This work investigates the femtosencond laser (fs-laser) induced periodical surface structures (FLIPSS) on titanium plate including the concentric rings, microgrooves and subwavelength ripples. The evolution of the three types of the structures at different laser fluence and shot number is investigated experimentally in detail. The competition mechanisms exist among the different FLIPSS. A processing window for each resulting FLIPSS is obtained. In order to give an overall understanding of the FLIPSS, the formation mechanisms of each type of FLIPSS are discussed. The formation of the ripples is well explained by the propagating of the surface plasma wave (SPW) on the air/Ti interface. The evolutions of the ripple distribution are well understood according to this model as well. It is concluded that the interaction of the scattered wave of the laser light with the surface wave is concluded to give rise to the microgroove structure. According to our observation, the shape of the concentric rings does not change with the variation of the laser fluence and pulse number. The structure could be originated from the optical interference between the transmitted and reflected laser beams by the two surfaces of the biconvex lens. This investigation could not only make a further understanding of the formations of FLIPSS but also provide the possibility to control the surface morphologies in laser processing.

  12. Quantum mechanical analysis of fractal conductance fluctuations: a picture using self-similar periodic orbits

    International Nuclear Information System (INIS)

    Ogura, Tatsuo; Miyamoto, Masanori; Budiyono, Agung; Nakamura, Katsuhiro

    2007-01-01

    Fractal magnetoconductance fluctuations are often observed in experiments on ballistic quantum dots. Although the analysis of the exact self-affine fractal has been given by the semiclassical theory using self-similar periodic orbits in systems with a soft-walled potential with a saddle, there has been no corresponding quantum mechanical investigation. We numerically calculate the quantum conductance with use of the recursive Green's function method applied to open cavities characterized by a Henon-Heiles type potential. The conductance fluctuations show exact self-affinity just as in some of the experimental observations. The enlargement factor for the horizontal axis can be explained by the scaling factor of the area of self-similar periodic orbits, and therefore be attributed to the curvature of the saddle in the cavity potential. The fractal dimension obtained through the box counting method agrees with those evaluated with use of the Hurst exponent, and coincides with the semiclassical prediction. We further investigate the variation of the fractal dimension by changing the control parameters between the classical and quantum domains. (fast track communication)

  13. Reliability of mechanisms with periodic random modal frequencies using an extreme value-based approach

    International Nuclear Information System (INIS)

    Savage, Gordon J.; Zhang, Xufang; Son, Young Kap; Pandey, Mahesh D.

    2016-01-01

    Resonance in a dynamic system is to be avoided since it often leads to impaired performance, overstressing, fatigue fracture and adverse human reactions. Thus, it is necessary to know the modal frequencies and ensure they do not coincide with any applied periodic loadings. For a rotating planar mechanism, the coefficients in the mass and stiffness matrices are periodically varying, and if the underlying geometry and material properties are treated as random variables then the modal frequencies are both position-dependent and probabilistic. The avoidance of resonance is now a complex problem. Herein, free vibration analysis helps determine ranges of modal frequencies that in turn, identify the running speeds of the mechanism to be avoided. This paper presents an efficient and accurate sample-based approach to determine probabilistic minimum and maximum extremes of the fundamental frequencies and the angular positions of their occurrence. Then, given critical lower and upper frequency constraints it is straightforward to determine reliability in terms of probability of exceedance. The novelty of the proposed approach is that the original expensive and implicit mechanistic model is replaced by an explicit meta-model that captures the tolerances of the design variables over the entire range of angular positions: position-dependent eigenvalues can be found easily and quickly. Extreme-value statistics of the modal frequencies and extreme-value statistics of the angular positions are readily computed through MCS. Limit-state surfaces that connect the frequencies to the design variables may be easily constructed. Error analysis identifies three errors and the paper presents ways to control them so the methodology can be sufficiently accurate. A numerical example of a flexible four-bar linkage shows the proposed methodology has engineering applications. The impact of the proposed methodology is two-fold: it presents a safe-side analysis based on free vibration methods to

  14. Coeur d'Alene Tribe Fisheries Program Research, Monitoring and Evaluation Plan; Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation, 1997-2002 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Angelo; Lamb, Dave; Peters, Ronald

    2002-11-01

    channel forms. In addition, ponds have been constructed to trap sediment from rill and gully erosion associated with agricultural practices, and to provide flow enhancement and ameliorate elevated stream temperatures during the summer base flow period. The implementation of restoration efforts that target the key habitats and lifestages for resident westslope cutthroat trout on the Coeur d'Alene Reservation is one means the Tribe is using to partially mitigate for lost anadromous fisheries. In this context, restoration is consistent with the definition provided by Ebersole et al. (1997), who described stream restoration as the reexpression of habitat capacity in a stream system. At the reach scale, habitat capacity is affected by biotic (e.g., riparian vegetation) and physical (e.g., flooding) processes. Superimposed on the natural biotic and physical processes are anthropogenic stressors (e.g., logging, roads and grazing) that suppress habitat capacity and can result in simplified, degraded stream reaches. The effectiveness of habitat restoration, measured as an increase in native trout abundance, is dependent on reducing limiting factors (e.g., passage barriers, high water temperatures, sediment transport from source areas) in areas that are critical for spawning and rearing lifestages. This plan outlines a monitoring strategy to help determine the effectiveness of specific restoration/enhancement treatments and to track the status of trout populations in four target watersheds.

  15. Recrudescence mechanisms and gene expression profile of the reproductive tracts from chickens during the molting period.

    Directory of Open Access Journals (Sweden)

    Wooyoung Jeong

    Full Text Available The reproductive system of chickens undergoes dynamic morphological and functional tissue remodeling during the molting period. The present study identified global gene expression profiles following oviductal tissue regression and regeneration in laying hens in which molting was induced by feeding high levels of zinc in the diet. During the molting and recrudescence processes, progressive morphological and physiological changes included regression and re-growth of reproductive organs and fluctuations in concentrations of testosterone, progesterone, estradiol and corticosterone in blood. The cDNA microarray analysis of oviductal tissues revealed the biological significance of gene expression-based modulation in oviductal tissue during its remodeling. Based on the gene expression profiles, expression patterns of selected genes such as, TF, ANGPTL3, p20K, PTN, AvBD11 and SERPINB3 exhibited similar patterns in expression with gradual decreases during regression of the oviduct and sequential increases during resurrection of the functional oviduct. Also, miR-1689* inhibited expression of Sp1, while miR-17-3p, miR-22* and miR-1764 inhibited expression of STAT1. Similarly, chicken miR-1562 and miR-138 reduced the expression of ANGPTL3 and p20K, respectively. These results suggest that these differentially regulated genes are closely correlated with the molecular mechanism(s for development and tissue remodeling of the avian female reproductive tract, and that miRNA-mediated regulation of key genes likely contributes to remodeling of the avian reproductive tract by controlling expression of those genes post-transcriptionally. The discovered global gene profiles provide new molecular candidates responsible for regulating morphological and functional recrudescence of the avian reproductive tract, and provide novel insights into understanding the remodeling process at the genomic and epigenomic levels.

  16. Goals of Pugwash in its ninth quinquennium (1997-2002)

    International Nuclear Information System (INIS)

    1999-01-01

    The enduring goals of the Pugwash Conference are: to anticipate and to find ways to avoid or diminish the ways in which innovations in science and technology may imperil the human condition (above all the threat to the every existence of mankind from nuclear weapons); to identify, to develop and promote the possibilities for more effective application of science and technology for the improvement of human well-being; to promote reflection on the ethical responsibilities of scientists to consider the consequence of their work (possible intended or unintended consequences) and ti try to individually or collectively minimize the chance of destructive consequences

  17. Pacific Northwest National Laboratory institutional plan FY 1997--2002

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    Pacific Northwest National Laboratory`s core mission is to deliver environmental science and technology in the service of the nation and humanity. Through basic research fundamental knowledge is created of natural, engineered, and social systems that is the basis for both effective environmental technology and sound public policy. Legacy environmental problems are solved by delivering technologies that remedy existing environmental hazards, today`s environmental needs are addressed with technologies that prevent pollution and minimize waste, and the technical foundation is being laid for tomorrow`s inherently clean energy and industrial processes. Pacific Northwest National Laboratory also applies its capabilities to meet selected national security, energy, and human health needs; strengthen the US economy; and support the education of future scientists and engineers. Brief summaries are given of the various tasks being carried out under these broad categories.

  18. An Optical Fiber Viscometer Based on Long-Period Fiber Grating Technology and Capillary Tube Mechanism

    Directory of Open Access Journals (Sweden)

    Jian-Neng Wang

    2010-12-01

    Full Text Available This work addresses the development and assessment of a fiber optical viscometer using a simple and low-cost long-period fiber grating (LPFG level sensor and a capillary tube mechanism. Previous studies of optical viscosity sensors were conducted by using different optical sensing methods. The proposed optical viscometer consists of an LPFG sensor, a temperature-controlled chamber, and a cone-shaped reservoir where gravitational force could cause fluid to flow through the capillary tube. We focused on the use of LPFGs as level sensors and the wavelength shifts were not used to quantify the viscosity values of asphalt binders. When the LPFG sensor was immersed in the constant volume (100 mL AC-20 asphalt binder, a wavelength shift was observed and acquired using LabVIEW software and GPIB controller. The time spent between empty and 100 mL was calculated to determine the discharge time. We simultaneously measured the LPFG-induced discharge time and the transmission spectra both in hot air and AC-20 asphalt binder at five different temperatures, 60, 80, 100, 135, and 170 Celsius. An electromechanical rotational viscometer was also used to measure the viscosities, 0.15–213.80 Pa·s, of the same asphalt binder at the above five temperatures. A non-linear regression analysis was performed to convert LPFG-induced discharge time into viscosities. Comparative analysis shows that the LPFG-induced discharge time agreed well with the viscosities obtained from the rotational viscometer.

  19. High-speed landslide mechanism extracted from long-period surface waves

    Science.gov (United States)

    Zhao, Juan

    2016-04-01

    Long-period seismic signals gathered at stations far from landslide area can be used to recover the landslide source force applied on ground during the rapid sliding process. This force history is helpful to improve our ability to deduce the characteristics of the event as well as the dynamic properties of bulk motion. We use source mechanism inversion to analyse two different large landslides. Seismic waves generated by these two events have been recorded respectively by more than 5 stations, with the distance range from 69km to 1325km. The first event is the sudden failure happened at Qianjiangping village (30.97°N, 110.61°E) on 13 July 2003, on the bank of the Qinggan river. The landslide flow brought about 20 million cubic meters rock and soil masses right into the river in a short time. It moved about 250 meters in the main sliding direction of S45°E before stopped by the opposite bank. It is a typical reservoir landslide, which has been compared to the 1963 Vaiont landslide in Italy. The other event is the Xiaolin (120.64°E; 23.16°N) deep-seated landslide, located in southwestern Taiwan and had volume of about 27 million cubic meters. The landslide moved in the westward direction, divided into two streams at about the middle of the run-out, because there had been a small ridge and two valleys extended from the west side of the ridge. The deposit spreading length of this landslide is about 2300 meters. We discuss the different characteristics of the two events in both geological structure and movement mode based on the field survey. Then we show that those differences are also revealed by the source force-time functions from inversion.

  20. Formation mechanisms of periodic longitudinal microstructure and texture patterns in friction stir welded magnesium AZ80

    Energy Technology Data Exchange (ETDEWEB)

    Hiscocks, J., E-mail: j.hiscocks@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, Ontario (Canada); Diak, B.J. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, Ontario (Canada); Gerlich, A.P. [Department of Mechanical and Mechatronics Engineering, Waterloo University, Waterloo, Ontario (Canada); Daymond, M.R. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, Ontario (Canada)

    2016-12-15

    Many studies of friction stir welding have shown that periodicity of metal flow around the tool pin may result in the formation of periodic differences in microstructure and texture in the weld nugget area correlated with the weld pitch. The current work investigates the periodicity of magnesium weld microtexture in the nugget region and its association with material flow using optical and electron microscopy. Two welds created in AZ80 at different processing conditions are presented in detail, one illustrating periodic longitudinal texture change, and one showing for the first time that periodic variations in texture, grain size, or composition are not defining features of periodic nugget flow. While nugget texture is dominated by shear deformation, it was found here to be affected to a lesser degree by compaction of material behind the welding tool, which led to reduction in intensity of the shear texture fiber. The decreased tendency for magnesium based alloys to form periodic patterns as compared to aluminum based alloys is explained with reference to the shear textures. - Highlights: •It is shown here that periodic material flow in the nugget does not necessitate longitudinal texture patterns. •Longitudinal texture patterns are shown to be present or absent in Mg AZ80 based on processing conditions. •Texture in the nugget is mainly dictated by shear deformation, but has measurable effects from other deformation modes. •Explanation of why longitudinal texture change is frequently reported in aluminum but not magnesium alloys is provided. •A new vector visualization of material flow based on EBSD data analysis is shown.

  1. Existence and asymptotic estimates of periodic solutions of El Niño mechanism of atmospheric physics

    International Nuclear Information System (INIS)

    Xiao-Jing, Li

    2010-01-01

    This paper is devoted to studying the El Niño mechanism of atmospheric physics. The existence and asymptotic estimates of periodic solutions for its model are obtained by employing the technique of upper and lower solution, and using the continuation theorem of coincidence degree theory. (general)

  2. Effective mechanical means of uterine cervix accelerating maturity in pregnant women of first mature age period of different somatotypes

    Directory of Open Access Journals (Sweden)

    Yakovleva О.V.

    2013-03-01

    Full Text Available The purpose is to evaluate the effectiveness of stimulation of delivery in first mature age period of pregnant women mechanically in different somatotypes. Materials and Methods: 658 patients at 38-41 weeks of gestation of the first period of mature age (22-35 years have been considered. Differentiation by somatotypes has been performed by the method of HT Kaarma (1991. All patients of each somatotype have been divided into primiparous (n = 402 and multiparous (n = 256. Preparation for delivery by mechanical means: on the 1 st day it was introduced into the cervical canal for 16 hours, on the 2nd day — Foley catheter for 8-16 hours (before the birth. Results: In multiparous women the application of mechanical preparation of the birth canal has been effective regardless of somatotype. The percentage of operative delivery in mechanical induction has been lower in multiparous women and also not related to somatotype. In nulliparous women of asthenic and normosthenic type greater efficiency of mechanical induction in preparation for delivery has been revealed. In asthenic and pyknictype mechanical induction has been inefficient and therefore has not been recommended for the use. Conclusion: Application of mechanical means of stimulation of delivery in nulliparous pregnant women should be performed according to their somatotype.

  3. 77 FR 2988 - Extension of Public Comment Period; Mechanisms of Compliance With United States Citizenship...

    Science.gov (United States)

    2012-01-20

    ... with a wide variety of complex organizational structures and trading practices. DATES: Comments and... mechanisms employed by companies that utilize a wide variety of organizational structures, and the additional... on the ``Submit a Comment'' box, which will then become highlighted in blue. In the ``Document Type...

  4. On a possible mechanism of quasi periodic pulses of the quiet Sun decametric radio emission

    International Nuclear Information System (INIS)

    Levin, B.N.; Snegireva, S.D.

    1983-01-01

    The observed fluctuations of the quiet Sun decametric radio emission are interpreted on the basis of the plasma mechanism of generation. These fluctuations may be caused by modulation of the optical depth of the radio source due to propagation of the sound wave packet through the corona

  5. Periodic, Quasi-Periodic and Chaotic Motions in Celestial Mechanics: Theory and Applications Selected papers from the Fourth Meeting on Celestial Mechanics, CELMEC IV San Martino al Cimino (Italy), 11–16 September 2005

    CERN Document Server

    Celletti, A

    2006-01-01

    The book provides the most recent advances of Celestial Mechanics, as provided by high-level scientists working in this field. It covers theoretical investigations as well as applications to concrete problems. Outstanding review papers are included in the book and they introduce the reader to leading subjects, like the variational approaches to find periodic orbits, the stability theory of the N-body problem, the spin-orbit resonances and chaotic dynamics, the space debris polluting the circumterrestrial space.

  6. Tsallis non-extensive statistical mechanics in the ionospheric detrended total electron content during quiet and storm periods

    Science.gov (United States)

    Ogunsua, B. O.; Laoye, J. A.

    2018-05-01

    In this paper, the Tsallis non-extensive q-statistics in ionospheric dynamics was investigated using the total electron content (TEC) obtained from two Global Positioning System (GPS) receiver stations. This investigation was carried out considering the geomagnetically quiet and storm periods. The micro density variation of the ionospheric total electron content was extracted from the TEC data by method of detrending. The detrended total electron content, which represent the variation in the internal dynamics of the system was further analyzed using for non-extensive statistical mechanics using the q-Gaussian methods. Our results reveals that for all the analyzed data sets the Tsallis Gaussian probability distribution (q-Gaussian) with value q > 1 were obtained. It was observed that there is no distinct difference in pattern between the values of qquiet and qstorm. However the values of q varies with geophysical conditions and possibly with local dynamics for the two stations. Also observed are the asymmetric pattern of the q-Gaussian and a highly significant level of correlation for the q-index values obtained for the storm periods compared to the quiet periods between the two GPS receiver stations where the TEC was measured. The factors responsible for this variation can be mostly attributed to the varying mechanisms resulting in the self-reorganization of the system dynamics during the storm periods. The result shows the existence of long range correlation for both quiet and storm periods for the two stations.

  7. Short-period atmospheric gravity waves - A study of their statistical properties and source mechanisms

    Science.gov (United States)

    Gedzelman, S. D.

    1983-01-01

    Gravity waves for the one year period beginning 19 October 1976 around Palisades, New York, are investigated to determine their statistical properties and sources. The waves have typical periods of 10 min, pressure amplitudes of 3 Pa and velocities of 30 m/s. In general, the largest, amplitude waves occur during late fall and early winter when the upper tropospheric winds directly overhead are fastest and the static stability of the lower troposphere is greatest. Mean wave amplitudes correlate highly with the product of the mean maximum wind speed and the mean low level stratification directly aloft. A distinct diurnal variation of wave amplitudes with the largest waves occurring in the pre-dawn hours is also observed as a result of the increased static stability then. The majority of waves are generated by shear instability; however, a number of waves are generated by distant sources such as nuclear detonations or large thunderstorms. The waves with distant sources can be distinguished on the basis of their generally much higher coherency across the grid and velocities that depart markedly from the wind velocity at any point in the sounding.

  8. The mechanics of green power : emission benefits and credits in voluntary and commitment periods

    International Nuclear Information System (INIS)

    Hyndman, R.

    1998-01-01

    The challenge facing the electric power industry in reducing greenhouse gas emissions under the Kyoto Protocol was discussed. The paper illustrates the emission reduction incentives prior to and during the commitment period, with particular focus on pricing. It was noted that in the absence of greenhouse gas emission reduction incentives and prices, coal has a lower running cost and would be dispatched ahead of oil and natural gas. The same situation exists with respect to nuclear, hydro and wind, all of which have lower marginal running costs than fossil fuel plants, thus will run ahead of fossil fuel plants wherever they are available. Various models of the electricity market in North America were demonstrated. The issue of how to determine the amount of greenhouse gas offset and its significance was also addressed. figs

  9. Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans

    OpenAIRE

    Silvani, Alessandro; Calandra-Buonaura, Giovanna; Johnson, Blair D.; van Helmond, Noud; Barletta, Giorgio; Cecere, Anna G.; Joyner, Michael J.; Cortelli, Pietro

    2017-01-01

    The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological mechanisms that mediate the coupling between HP and SAP in response to different postures, we analyzed the cross-correlation functions between low-frequency HP and SAP fluctuations and estimated cBR...

  10. Quantum mechanical analysis of the equilateral triangle billiard: Periodic orbit theory and wave packet revivals

    International Nuclear Information System (INIS)

    Doncheski, M.A.; Robinett, R.W.

    2002-01-01

    Using the fact that the energy eigenstates of the equilateral triangle infinite well (or billiard) are available in closed form, we examine the connections between the energy eigenvalue spectrum and the classical closed paths in this geometry, using both periodic orbit theory and the short-term semi-classical behavior of wave packets. We also discuss wave packet revivals and show that there are exact revivals, for all wave packets, at times given by T rev =9μa 2 /4(h/2π) where a and μ are the length of one side and the mass of the point particle, respectively. We find additional cases of exact revivals with shorter revival times for zero-momentum wave packets initially located at special symmetry points inside the billiard. Finally, we discuss simple variations on the equilateral (60 deg. -60 deg. -60 deg. ) triangle, such as the half equilateral (30 deg. -60 deg. -90 deg.) triangle and other 'foldings', which have related energy spectra and revival structures

  11. Working memory delay period activity marks a domain-unspecific attention mechanism.

    Science.gov (United States)

    Katus, Tobias; Müller, Matthias M

    2016-03-01

    Working memory (WM) recruits neural circuits that also perform perception- and action-related functions. Among the functions that are shared between the domains of WM and perception is selective attention, which supports the maintenance of task-relevant information during the retention delay of WM tasks. The tactile contralateral delay activity (tCDA) component of the event-related potential (ERP) marks the attention-based rehearsal of tactile information in somatosensory brain regions. We tested whether the tCDA reflects the competition for shared attention resources between a WM task and a perceptual task under dual-task conditions. The two tasks were always performed on opposite hands. In different blocks, the WM task had higher or lower priority than the perceptual task. The tCDA's polarity consistently reflected the hand where the currently prioritized task was performed. This suggests that the process indexed by the tCDA is not specific to the domain of WM, but mediated by a domain-unspecific attention mechanism. The analysis of transient ERP components evoked by stimuli in the two tasks further supports the interpretation that the tCDA marks a goal-directed bias in the allocation of selective attention. Larger spatially selective modulations were obtained for stimulus material related to the high-, as compared to low-priority, task. While our results generally indicate functional overlap between the domains of WM and perception, we also found evidence suggesting that selection in internal (mnemonic) and external (perceptual) stimulus representations involves processes that are not active during shifts of preparatory attention. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Periodic Density Functional Theory Study of the Structure, Raman Spectrum, and Mechanical Properties of Schoepite Mineral.

    Science.gov (United States)

    Colmenero, Francisco; Cobos, Joaquín; Timón, Vicente

    2018-04-16

    The structure and Raman spectrum of schoepite mineral, [(UO 2 ) 8 O 2 (OH) 12 ]·12H 2 O, was studied by means of theoretical calculations. The computations were carried out by using density functional theory with plane waves and pseudopotentials. A norm-conserving pseudopotential specific for the U atom developed in a previous work was employed. Because it was not possible to locate H atoms directly from X-ray diffraction (XRD) data by structure refinement in previous experimental studies, all of the positions of the H atoms in the full unit cell were determined theoretically. The structural results, including the lattice parameters, bond lengths, bond angles, and powder XRD pattern, were found to be in good agreement with their experimental counterparts. However, the calculations performed using the unit cell designed by Ostanin and Zeller in 2007, involving half of the atoms of the full unit cell, led to significant errors in the computed powder XRD pattern. Furthermore, Ostanin and Zeller's unit cell contains hydronium ions, H 3 O + , which are incompatible with the experimental information. Therefore, while the use of this schoepite model may be a very useful approximation requiring a much smaller amount of computational effort, the full unit cell should be used to study this mineral accurately. The Raman spectrum was also computed by means of density functional perturbation theory and compared with the experimental spectrum. The results were also in agreement with the experimental data. A normal-mode analysis of the theoretical spectra was performed to assign the main bands of the Raman spectrum. This assignment significantly improved the current empirical assignment of the bands of the Raman spectrum of schoepite mineral. In addition, the equation of state and elastic properties of this mineral were determined. The crystal structure of schoepite was found to be stable mechanically and dynamically. Schoepite can be described as a brittle material exhibiting

  13. Mechanical and tribological properties of a-C/a-C:Ti multilayer films with various bilayer periods

    Energy Technology Data Exchange (ETDEWEB)

    Bai, W.Q.; Cai, J.B.; Wang, X.L., E-mail: wangxl@zju.edu.cn; Wang, D.H.; Gu, C.D.; Tu, J.P., E-mail: tujp@zju.edu.cn

    2014-05-02

    Thick a-C/a-C:Ti multilayer films with bilayer periods of 12–70 nm were deposited on Ti6Al4V alloy substrate by means of closed field unbalance magnetron sputtering. The morphology and microstructure of the multilayer films were investigated by scanning electron microscopy, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Nanocrystalline TiC was distributed in the a-C:Ti layer and at the interface between the two adjacent layers. The mechanical and tribological properties were evaluated by Rockwell and scratch tests, a nanoindentor and a ball-on-disk tribometer. The multilayer film with a bilayer period of 12 nm showed the highest adhesion strength, hardness (26 GPa) and elastic modulus (232 GPa); it also had the lowest average coefficient of friction (0.09) and a wear rate of 8.06 × 10{sup −17} m{sup 3} N{sup −1} m{sup −1}. - Highlights: • a-C/a-C:Ti multilayers with various bilayer periods were prepared. • Nanocrystalline TiCs were confirmed in the a-C:Ti layer and at the interface. • These multilayers show fine ability to comply with substrate deformation. • The multilayer with a bilayer period of 12 nm exhibits the best properties.

  14. Mechanical properties of ceramic structures based on Triply Periodic Minimal Surface (TPMS) processed by 3D printing

    Science.gov (United States)

    Restrepo, S.; Ocampo, S.; Ramírez, J. A.; Paucar, C.; García, C.

    2017-12-01

    Repairing tissues and organs has been the main goal of surgical procedures. Since the 1990s, the main goal of tissue engineering has been reparation, using porous scaffolds that serve as a three-dimensional template for the initial fixation of cells and subsequent tissue formation both in vitro and in vivo. A scaffold must have specific characteristics of porosity, interconnectivity, surface area, pore volume, surface tortuosity, permeability and mechanical properties, which makes its design, manufacturing and characterization a complex process. Inspired by nature, triply periodic minimal surfaces (TPMS) have emerged as an alternative for the manufacture of porous pieces with design requirements, such as scaffolds for tissue repair. In the present work, we used the technique of 3D printing to obtain ceramic structures with Gyroid, Schwarz Primitive and Schwarz Diamond Surfaces shapes, three TPMS that fulfil the geometric requirements of a bone tissue scaffold. The main objective of this work is to compare the mechanical properties of ceramic pieces of three different forms of TPMS printed in 3D using a commercial ceramic paste. In this way it will be possible to clarify which is the TPMS with appropriate characteristics to construct scaffolds of ceramic materials for bone repair. A dependence of the mechanical properties with the geometry was found being the Primitive Surface which shows the highest mechanical properties.

  15. Analysis of Seismotektonic Patterns in Sumatra Region Based on the Focal Mechanism of Earthquake Period 1976-2016

    Science.gov (United States)

    Indah, F. P.; Syafriani, S.; Andiyansyah, Z. S.

    2018-04-01

    Sumatra is in an active subduction zone between the indo-australian plate and the eurasian plate and is located at a fault along the sumatra fault so that sumatra is vulnerable to earthquakes. One of the ways to find out the cause of earthquake can be done by identifying the type of earthquake-causing faults based on earthquake of focal mechanism. The data used to identify the type of fault cause of earthquake is the earth tensor moment data which is sourced from global cmt period 1976-2016. The data used in this research using magnitude m ≥ 6 sr. This research uses gmt software (generic mapping tolls) to describe the form of fault. From the research result, it is found that the characteristics of fault field that formed in every region in sumatera island based on data processing and data of earthquake history of 1976-2016 period that the type of fault in sumatera fault is strike slip, fault type in mentawai fault is reverse fault (rising faults) and dip-slip, while the fault type in the subduction zone is dip-slip.

  16. Periodic driving control of Raman-induced spin-orbit coupling in Bose-Einstein condensates: The heating mechanisms

    Science.gov (United States)

    Gomez Llorente, J. M.; Plata, J.

    2016-06-01

    We focus on a technique recently implemented for controlling the magnitude of synthetic spin-orbit coupling (SOC) in ultracold atoms in the Raman-coupling scenario. This technique uses a periodic modulation of the Raman-coupling amplitude to tune the SOC. Specifically, it has been shown that the effect of a high-frequency sinusoidal modulation of the Raman-laser intensity can be incorporated into the undriven Hamiltonian via effective parameters, whose adiabatic variation can therefore be used to tune the SOC. Here, we characterize the heating mechanisms that can be relevant to this method. We identify the main mechanism responsible for the heating observed in the experiments as basically rooted in driving-induced transfer of population to excited states. Characteristics of that process determined by the harmonic trapping, the decay of the excited states, and the technique used for preparing the system are discussed. Additional heating, rooted in departures from adiabaticity in the variation of the effective parameters, is also described. Our analytical study provides some clues that may be useful in the design of strategies for curbing the effects of heating on the efficiency of the control methods.

  17. Periodic Viscous Shear Heating Instability in Fine-Grained Shear Zones: Possible Mechanism for Intermediate Depth Earthquakes and Slow Earthquakes?

    Science.gov (United States)

    Kelemen, P. B.; Hirth, G.

    2004-12-01

    creep and grain boundary sliding as a function of stress and strain, and undergoes diffusive growth during diffusion creep. For strain rates ca E-13 per second and initial temperatures ca 600 to 850 C, this model produces periodic viscous shear heating events with periods of 100's of years. Strain rates during these events approach 1 per second as temperatures reach 1400 C, so future models will incorporate inertial terms in the stress. Cooling between events returns the shear zone almost to its initial temperature, but ultimately shear zone temperature between events exceeds 850 C resulting in stable viscous creep. Back of the envelope calculations based on model results support the view that viscous deformation in both shear zone and host will be mainly via grain-size sensitive creep, and thus deformation will remain localized in shear zones. Similarly, we infer that inertial terms will remain small. Future models will test and quantify these inferences. The simple model described above provides an attractive explanation for intermediate-depth earthquakes, especially those in subduction zones that occur in a narrow thermal window (e.g., Hacker et al JGR 2003). We think that a "smoother"periodic instability might be produced via the same mechanism in weaker materials, which could provide a viscous mechanism for some slow earthquakes. By AGU, we will construct a second, simple model using quartz rheology to investigate this. Finally, coupling of viscous shear heating instabilities in the shallow mantle with brittle stick-slip deformation in the weaker, overlying crust may influence earthquake frequency.

  18. Thermo-Mechanical Effect on Poly Crystalline Boron Nitride Tool Life During Friction Stir Welding (Dwell Period)

    Science.gov (United States)

    Almoussawi, M.; Smith, A. J.

    2018-03-01

    Poly Crystalline Boron Nitride (PCBN) tool wear during the friction stir welding of high melting alloys is an obstacle to commercialize the process. This work simulates the friction stir welding process and tool wear during the plunge/dwell period of 14.8 mm EH46 thick plate steel. The Computational Fluid Dynamic (CFD) model was used for simulation and the wear of the tool is estimated from temperatures and shear stress profile on the tool surface. Two sets of tool rotational speeds were applied including 120 and 200 RPM. Seven plunge/dwell samples were prepared using PCBN FSW tool, six thermocouples were also embedded around each plunge/dwell case in order to record the temperatures during the welding process. Infinite focus microscopy technique was used to create macrographs for each case. The CFD result has been shown that a shear layer around the tool shoulder and probe-side denoted as thermo-mechanical affected zone (TMAZ) was formed and its size increase with tool rotational speed increase. Maximum peak temperature was also found to increase with tool rotational speed increase. PCBN tool wear under shoulder was found to increase with tool rotational speed increase as a result of tool's binder softening after reaching to a peak temperature exceeds 1250 °C. Tool wear also found to increase at probe-side bottom as a result of high shear stress associated with the decrease in the tool rotational speed. The amount of BN particles revealed by SEM in the TMAZ were compared with the CFD model.

  19. Thermo-Mechanical Effect on Poly Crystalline Boron Nitride Tool Life During Friction Stir Welding (Dwell Period)

    Science.gov (United States)

    Almoussawi, M.; Smith, A. J.

    2018-05-01

    Poly Crystalline Boron Nitride (PCBN) tool wear during the friction stir welding of high melting alloys is an obstacle to commercialize the process. This work simulates the friction stir welding process and tool wear during the plunge/dwell period of 14.8 mm EH46 thick plate steel. The Computational Fluid Dynamic (CFD) model was used for simulation and the wear of the tool is estimated from temperatures and shear stress profile on the tool surface. Two sets of tool rotational speeds were applied including 120 and 200 RPM. Seven plunge/dwell samples were prepared using PCBN FSW tool, six thermocouples were also embedded around each plunge/dwell case in order to record the temperatures during the welding process. Infinite focus microscopy technique was used to create macrographs for each case. The CFD result has been shown that a shear layer around the tool shoulder and probe-side denoted as thermo-mechanical affected zone (TMAZ) was formed and its size increase with tool rotational speed increase. Maximum peak temperature was also found to increase with tool rotational speed increase. PCBN tool wear under shoulder was found to increase with tool rotational speed increase as a result of tool's binder softening after reaching to a peak temperature exceeds 1250 °C. Tool wear also found to increase at probe-side bottom as a result of high shear stress associated with the decrease in the tool rotational speed. The amount of BN particles revealed by SEM in the TMAZ were compared with the CFD model.

  20. Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans.

    Science.gov (United States)

    Silvani, Alessandro; Calandra-Buonaura, Giovanna; Johnson, Blair D; van Helmond, Noud; Barletta, Giorgio; Cecere, Anna G; Joyner, Michael J; Cortelli, Pietro

    2017-01-01

    The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological mechanisms that mediate the coupling between HP and SAP in response to different postures, we analyzed the cross-correlation functions between low-frequency HP and SAP fluctuations and estimated cBRS with the sequence technique in healthy male subjects during passive head-up tilt test (HUTT, n = 58), during supine wakefulness, supine slow-wave sleep (SWS), and in the seated and active standing positions ( n = 8), and during progressive loss of 1 L blood ( n = 8) to decrease central venous pressure in the supine position. HUTT, SWS, the seated, and the standing positions, but not blood loss, entailed significant increases in the positive correlation between HP and the previous SAP values, which is the expected result of arterial baroreflex control, compared with baseline recordings in the supine position during wakefulness. These increases were mirrored by increases in the low-frequency variability of SAP in each condition but SWS. cBRS decreased significantly during HUTT, in the seated and standing positions, and after blood loss compared with baseline during wakefulness. These decreases were mirrored by decreases in the RMSSD index, which reflects cardiac vagal modulation. These results support the view that the cBRS decrease associated with the upright posture is a byproduct of decreased cardiac vagal modulation, triggered by the arterial baroreflex in response to central hypovolemia. Conversely, the greater baroreflex contribution to cardiac control associated with upright posture may be explained, at least in part, by enhanced fluctuations of SAP, which elicit a more effective entrainment of HP fluctuations by the arterial baroreflex. These SAP fluctuations may result

  1. Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

    International Nuclear Information System (INIS)

    Gao, Gongming; Shen, Nan; Jiang, Xuefeng; Sun, Huiqing; Xu, Nanwei; Zhou, Dong; Nong, Luming; Ren, Kewei

    2016-01-01

    The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferation (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.

  2. Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Gongming [Department of Orthopedics, The Affiliated Changzhou No. 2 Hospital of Nanjing Medical University, Changzhou 213003 (China); Shen, Nan [Department of Clinical Pharmacy, The Affiliated Jiangyin Hospital of Southeast University Medical School, Jiangyin 214400 (China); Jiang, Xuefeng; Sun, Huiqing [Department of Orthopedics, The Affiliated Jiangyin Hospital of Southeast University Medical School, Jiangyin 214400 (China); Xu, Nanwei; Zhou, Dong [Department of Orthopedics, The Affiliated Changzhou No. 2 Hospital of Nanjing Medical University, Changzhou 213003 (China); Nong, Luming, E-mail: lumingnong@hotmail.com [Department of Orthopedics, The Affiliated Changzhou No. 2 Hospital of Nanjing Medical University, Changzhou 213003 (China); Ren, Kewei, E-mail: keweiren@hotmail.com [Department of Orthopedics, The Affiliated Jiangyin Hospital of Southeast University Medical School, Jiangyin 214400 (China)

    2016-01-15

    The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferation (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.

  3. Exercise following a short immobilization period is detrimental to tendon properties and joint mechanics in a rat rotator cuff injury model.

    Science.gov (United States)

    Peltz, Cathryn D; Sarver, Joseph J; Dourte, Leann M; Würgler-Hauri, Carola C; Williams, Gerald R; Soslowsky, Louis J

    2010-07-01

    Rotator cuff tears are a common clinical problem that can result in pain and disability. Previous studies in a rat model showed enhanced tendon to bone healing with postoperative immobilization. The objective of this study was to determine the effect of postimmobilization activity level on insertion site properties and joint mechanics in a rat model. Our hypothesis was that exercise following a short period of immobilization will cause detrimental changes in insertion site properties compared to cage activity following the same period of immobilization, but that passive shoulder mechanics will not be affected. We detached and repaired the supraspinatus tendon of 22 Sprague-Dawley rats, and the injured shoulder was immobilized postoperatively for 2 weeks. Following immobilization, rats were prescribed cage activity or exercise for 12 weeks. Passive shoulder mechanics were determined, and following euthanasia, tendon cross-sectional area and mechanical properties were measured. Exercise following immobilization resulted in significant decreases compared to cage activity in range of motion, tendon stiffness, modulus, percent relaxation, and several parameters from both a structurally based elastic model and a quasi-linear viscoelastic model. Therefore, we conclude that after a short period of immobilization, increased activity is detrimental to both tendon mechanical properties and shoulder joint mechanics, presumably due to increased scar production. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc

  4. Control technique of spontaneous combustion in fully mechan ized stope during period of end caving under complex mining influence

    Science.gov (United States)

    Yuan, Benqing

    2018-01-01

    In view of the phenomenon of spontaneous combustion of coal seam occurring during the period of end caving under complex mining conditions, taking the 1116 (3) stope of Guqiao mine as the object of study, the causes of spontaneous combustion during the period of end caving are analyzed, according to the specific geological conditions of the stope to develop corresponding fire prevention measures, including the reduction of air supply and air leakage in goaf, reduce the amount of coal left, reasonable drainage, nitrogen injection for spontaneous combustion prevention, grouting for spontaneous combustion prevention and permanent closure, fundamentally eliminates the potential for spontaneous combustion during the period of 1116(3) stope end caving. The engineering practice shows that this kind of measure has reference value for the prevention and control of spontaneous combustion during the period of stope end caving.

  5. Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans

    NARCIS (Netherlands)

    Silvani, A.; Calandra-Buonaura, G.; Johnson, B.D.; Helmond, N. van; Barletta, G.; Cecere, A.G.; Joyner, M.J.; Cortelli, P.

    2017-01-01

    The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological

  6. Effect of modulation periods on the microstructure and mechanical properties of DLC/TiC multilayer films deposited by filtered cathodic vacuum arc method

    International Nuclear Information System (INIS)

    Xu, Zhaoying; Sun, H.; Leng, Y.X.; Li, Xueyuan; Yang, Wenmao; Huang, N.

    2015-01-01

    Highlights: • DLC/TiC multilayer films with different modulation periods at same modulation ratio 1:1 were deposited by FCVA. • The residual stress of DLC/TiC multilayer films decreases with the modulation periods decrease. • The hardness of the multilayer DLC films decreases with modulation periods increasing. - Abstract: The high stress of diamond-like carbon (DLC) film limits its thickness and adhesion on substrate. Multilayer structure is one approach to overcome this disadvantage. In this paper, the DLC/TiC multilayer films with different modulation periods (80 nm, 106 nm or 160 nm) at same modulation ratio of 1:1 were deposited on Si(1 0 0) wafer and Ti-6Al-4V substrate by filtered cathodic vacuum arc (FCVA) technology. X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoindention and wear test were employed to investigate the effect of modulation periods on the microstructure and mechanical properties of the multilayer films. The results showed that the residual stress of the DLC/TiC multilayer films could be effectively reduced and the residual stress decreased with the modulation periods decreasing. The hardness of the DLC/TiC multilayer films increased with modulation periods decreasing. The DLC/TiC multilayer film with modulation period of 106 nm had the best wear resistance due to the good combination of hardness, ductility and low compressive stress

  7. LONG-ORBITAL-PERIOD PREPOLARS CONTAINING EARLY K-TYPE DONOR STARS. BOTTLENECK ACCRETION MECHANISM IN ACTION

    International Nuclear Information System (INIS)

    Tovmassian, G.; González–Buitrago, D.; Zharikov, S.; Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P.; Miroshnichenko, A. S.

    2016-01-01

    We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems

  8. LONG-ORBITAL-PERIOD PREPOLARS CONTAINING EARLY K-TYPE DONOR STARS. BOTTLENECK ACCRETION MECHANISM IN ACTION

    Energy Technology Data Exchange (ETDEWEB)

    Tovmassian, G.; González–Buitrago, D.; Zharikov, S. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 877, Ensenada, Baja California, 22800 México (Mexico); Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Campus Box 3255, Chapel Hill, NC 27599 (United States); Miroshnichenko, A. S., E-mail: gag@astro.unam.mx, E-mail: dgonzalez@astro.unam.mx, E-mail: zhar@astro.unam.mx [Department of Physics and Astronomy, University of North Carolina at Greensboro, Greensboro, NC 27402-6170 (United States)

    2016-03-01

    We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems.

  9. Contact angle hysteresis on doubly periodic smooth rough surfaces in Wenzel's regime: The role of the contact line depinning mechanism.

    Science.gov (United States)

    Iliev, Stanimir; Pesheva, Nina; Iliev, Pavel

    2018-04-01

    We report here on the contact angle hysteresis, appearing when a liquid meniscus is in contact with doubly sinusoidal wavelike patterned surfaces in Wenzel's wetting regime. Using the full capillary model we obtain numerically the contact angle hysteresis as a function of the surface roughness factor and the equilibrium contact angle for a block case and a kink case contact line depinning mechanism. We find that the dependencies of the contact angle hysteresis on the surface roughness factor are different for the different contact line depinning mechanisms. These dependencies are different also for the two types of rough surfaces we studied. The relations between advancing, receding, and equilibrium contact angles are investigated. A comparison with the existing asymptotical, numerical, and experimental results is carried out.

  10. Synergetic effect of topological cue and periodic mechanical tension-stress on osteogenic differentiation of rat bone mesenchymal stem cells.

    Science.gov (United States)

    Liu, Yao; Yang, Guang; Ji, Huanzhong; Xiang, Tao; Luo, En; Zhou, Shaobing

    2017-06-01

    Mesenchymal stem cells (MSCs) are able to self-renew and differentiate into tissues of mesenchymal origin, making them to be significant for cell-based therapies, such as metabolic bone diseases and bone repair. Regulating the differentiation of MSCs is significant for bone regeneration. Electrospun fibers mimicking natural extracellular matrix (ECM), is an effective artificial ECM to regulate the behaviors and fates of MSCs. The aligned electrospun fibers can modulate polar cell pattern of bone mesenchymal stem cells, which leads to more obvious osteogenic differentiation. Apart from the topographic effect of electrospun fibers, mechanical cues can also intervene the cell behaviors. In this study, the osteogenic differentiation of rat bone mesenchymal stem cells was evaluated, which were cultured on aligned/random electrospun fiber mats materials under mechanical tension intervention. Scanning electron microscope and immune-fluorescent staining were used to directly observe the polarity changing of cellular morphology and cytoskeleton. The results proved that aligned electrospun fibers could be more conducive to promote osteogenic differentiation of rat bone mesenchymal stem cells and this promotion of osteogenic differentiation was enhanced by tension intervention. These results were correlated to the quantitative real-time PCR assay. In general, culturing rat bone mesenchymal stem cells on electrospun fibers under the intervention of mechanical tension is an effective way to mimic a more real cellular microenvironment. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Influence of temperature of the short-period heat treatment on mechanical properties of the NiTi alloy

    Directory of Open Access Journals (Sweden)

    Jaroslav Čapek

    2014-01-01

    Full Text Available The equiatomic alloy of nickel and titanium, known as nitinol, possesses unique properties such as superelasticity, pseudoplasticity, shape memory, while maintaining good corrosion resistance and sufficient biocompatibility. Therefore it is used for production of various devices including surgery implants. Heat treatment of nickel-rich NiTi alloys can result in precipitation of nickel-rich phases, which strongly influence tensile and fatigue behaviour of the material.In this work we have studied influence of short-period heat treatment on tensile behaviour and fatigue life of the NiTi (50.9 at. % Ni wire intended for fabrication of surgery stents.

  12. [Mechanism of renal elimination of 2 elements of group IIIA of the periodic table : aluminum and indium].

    Science.gov (United States)

    Galle, P

    1981-01-05

    Aluminium and indium, two elements of group IIIA of the periodic table, are concentrated by the kidney inside lysosomes of proximal tubule cell. In these lysosomes, aluminium and indium are precipitated as non-soluble phosphate salts and these precipitates are then expelled in the tubular lumen and eliminated with the urinary flow. These data have been visualized by analytical microscopy (ion microscopy and X ray microanalysis). Local acid phosphatases are assumed to permit the concentration of aluminium and indium salts inside the lysosomes.

  13. Periodicity in the autocorrelation function as a mechanism for regularly occurring zero crossings or extreme values of a Gaussian process.

    Science.gov (United States)

    Wilson, Lorna R M; Hopcraft, Keith I

    2017-12-01

    The problem of zero crossings is of great historical prevalence and promises extensive application. The challenge is to establish precisely how the autocorrelation function or power spectrum of a one-dimensional continuous random process determines the density function of the intervals between the zero crossings of that process. This paper investigates the case where periodicities are incorporated into the autocorrelation function of a smooth process. Numerical simulations, and statistics about the number of crossings in a fixed interval, reveal that in this case the zero crossings segue between a random and deterministic point process depending on the relative time scales of the periodic and nonperiodic components of the autocorrelation function. By considering the Laplace transform of the density function, we show that incorporating correlation between successive intervals is essential to obtaining accurate results for the interval variance. The same method enables prediction of the density function tail in some regions, and we suggest approaches for extending this to cover all regions. In an ever-more complex world, the potential applications for this scale of regularity in a random process are far reaching and powerful.

  14. Periodicity in the autocorrelation function as a mechanism for regularly occurring zero crossings or extreme values of a Gaussian process

    Science.gov (United States)

    Wilson, Lorna R. M.; Hopcraft, Keith I.

    2017-12-01

    The problem of zero crossings is of great historical prevalence and promises extensive application. The challenge is to establish precisely how the autocorrelation function or power spectrum of a one-dimensional continuous random process determines the density function of the intervals between the zero crossings of that process. This paper investigates the case where periodicities are incorporated into the autocorrelation function of a smooth process. Numerical simulations, and statistics about the number of crossings in a fixed interval, reveal that in this case the zero crossings segue between a random and deterministic point process depending on the relative time scales of the periodic and nonperiodic components of the autocorrelation function. By considering the Laplace transform of the density function, we show that incorporating correlation between successive intervals is essential to obtaining accurate results for the interval variance. The same method enables prediction of the density function tail in some regions, and we suggest approaches for extending this to cover all regions. In an ever-more complex world, the potential applications for this scale of regularity in a random process are far reaching and powerful.

  15. Effects of electron beam irradiation on properties of corn starch undergone periodate oxidation mechanism blended with polyvinyl alcohol

    Science.gov (United States)

    Bee, Soo-Tueen; Sin, Lee Tin; Ratnam, C. T.; Yap, Bee-Fen; Rahmat, A. R.

    2018-02-01

    This work was performed to examine the properties of pristine PVOH and PVOH-starch blends under exposure of different irradiation dosages. The periodate oxidation method was used to produce dialdehyde starch. The application of low dosages of electron beam irradiation (≤10 kGy) has improved the tensile strength by forming crosslinking networks. However, the tensile strength drastically declined when radiated at 30 kGy due to the reduction of available hydroxyl groups inside polymer matrix for intermolecular interaction. Also, the incorporation of corn starch and dialdehyde starch has significantly reduced the melting temperature and enthalpy of melting of PVOH blends due to cessation of the hydrogen bonding between PVOH and starch molecules. The crystallite size for deflection planes (1 0 1), (1 0 1) and (2 0 0) for all PVOH blends was significant reduced when irradiated. The electron beam irradiation has also weakened the hydrophilic characteristic of all PVOH blends as evidenced in infrared and microscopy analysis.

  16. Periodic repression by the bHLH factor Hes7 is an essential mechanism for the somite segmentation clock

    Science.gov (United States)

    Bessho, Yasumasa; Hirata, Hiromi; Masamizu, Yoshito; Kageyama, Ryoichiro

    2003-01-01

    Hes7, a bHLH gene essential for somitogenesis, displays cyclic expression of mRNA in the presomitic mesoderm (PSM). Here, we show that Hes7 protein is also expressed in a dynamic manner, which depends on proteasome-mediated degradation. Spatial comparison revealed that Hes7 and Lunatic fringe (Lfng) transcription occurs in the Hes7 protein-negative domains. Furthermore, Hes7 and Lfng transcription is constitutively up-regulated in the absence of Hes7 protein and down-regulated by stabilization of Hes7 protein. Thus, periodic repression by Hes7 protein is critical for the cyclic transcription of Hes7 and Lfng, and this negative feedback represents a molecular basis for the segmentation clock. PMID:12783854

  17. On the mechanism of vomiting in the primary reaction period following whole-body irradiation at high doses

    International Nuclear Information System (INIS)

    Martirosov, K.S.; Grigor'ev, Yu.G.; Zorin, V.V.; Norkin, I.M.

    1997-01-01

    In the experiments of dogs exposed to ionizing radiations at doses of 50 and 70 Gy, an essential role of the central mechanism in the origin of early postradiation vomiting has been confirmed. Insufficient efficiency of dimethpramide, a dophaminolytics, in this case may be connected either with initiation of other (non-dophaminosensitive) structures of the chemoreceptor trigger zone or with a growing role of the reflex way of vomiting arising due to a considerable intestinal injury that causes diarrhea. The inhibition of intestinal M-cholinoreceptors by methacine prevented diarrhea but didn't change the intensity of the vomiting reaction which, however, dose not eliminate the possibility of afferentation from receptors that respond to others biologically active substances. (author)

  18. Computational and experimental fluid mechanics. Progress report no. 5 for period January 1. to December 31. 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The general purpose of the program is the development of efficient algorithms, their implementation in codes of Computational Fluid Mechanics (CFD), and the experimental verification of these codes. Flows of both fundamental and applied nature will be investigated, including flows in industrial process equipment, about aerodynamics structures and ships, and flows over bed forms of importance for sediment transport. The experimental work will include the development of improved techniques, emphasizing optical methods. The objectives will be met through a coordinated experimental and theoretical/computational research program, organized in 7 specific projects: 1. CFD-methods and algorithms. 2. Spectral element simulation of ultrafiltration. 3. Turbulent swirling flows. 4. Near-wall models of turbulence. 5. Flow over bed forms. 6. Flow past ship hull. 7. Development of experimental techniques. (EG) 10 refs.

  19. Factors associated to the length of time on mechanical ventilation in the postoperative period of cardiac surgery

    Directory of Open Access Journals (Sweden)

    Laura Fonseca

    Full Text Available Our objective was to identify factors associated with the duration of mechanical ventilation (MV postoperative to cardiac surgery and assess the association between duration of endotracheal intubation, length of stay in the Intensive Care Unit (ICU and hospital. Longitudinal, retrospective study of medical records of 116 adults undergoing cardiac surgery from March 2012 to May 2013. The mean age was 57±14 years, predominantly male and coronary artery bypass grafting surgery (52.6%. The MV time was 15.25(7.66 to 23.68 hours. Associated with longer MV was the age (r=0.5,p<0.001, comorbidities (r=0.344,p<0.001, cardiopulmonary bypass time (r=0.244,p=0.008, duration of continuous sedation (r=0.607,p<0.001, sedative doses (r=0.4, p<0.001, time of vasoconstrictors and vasodilators (r=0.711, p< 0.001, r=0.368, p<0.001, drainage of the 1st time (r=0.201, p<0.031, presence of drains (r=0.445, p<0.001, postoperative complications (r=0.524, p< 0.001 and hospital stay. Our data confirms that both preoperative, transoperative and postoperative variables prolong the VM and therefore the hospital stay.

  20. Trends and molecular mechanisms of antimicrobial resistance in clinical staphylococci isolated from companion animals over a 16 year period.

    Science.gov (United States)

    Couto, Natacha; Monchique, Cláudia; Belas, Adriana; Marques, Cátia; Gama, Luís T; Pomba, Constança

    2016-06-01

    The objective of this study was to investigate the evolution of resistance to antimicrobials, corresponding mechanisms and molecular characteristics of Staphylococcus spp., between 1999 and 2014. Susceptibility to 38 antimicrobials was determined for 632 clinical staphylococcal isolates obtained from companion animals (dogs, cats, horses and other animals). Twenty antimicrobial resistance genes, including mecA and mecC, were screened by PCR. Methicillin-resistant staphylococci were characterized by spa (Staphylococcus aureus), SCCmec, MLST and PFGE typing. Statistical analyses were performed using SAS v9.3 and differences were considered relevant if P ≤ 0.05. The mecA gene was identified in 74 staphylococcal isolates (11.6%): 11 MRSA (40.7%), 40 methicillin-resistant Staphylococcus pseudintermedius (MRSP; 8.7%) and 23 methicillin-resistant CoNS (26.7%). Resistance to the majority of antimicrobials and the number of mecA-positive isolates increased significantly over time. Eighteen spa types were identified, including two new ones. MRSA isolates were divided into three PFGE clusters that included ST22-IV, ST105-II, ST398-V and ST5-VI. Most methicillin-resistant Staphylococcus epidermidis isolates were of clonal complex (CC) 5, including a new ST, and clustered in eight PFGE clusters. MRSP were grouped into five PFGE clusters and included ST45-NT, ST71-II-III, ST195-III, ST196-V, ST339-NT, ST342-IV and the new ST400-III. Methicillin-resistant Staphylococcus haemolyticus clustered in two PFGE clusters. The significant increase in antimicrobial-resistant and mecA-positive isolates in recent years is worrying. Furthermore, several isolates are MDR, which complicates antimicrobial treatment and increases the risk of transfer to humans or human isolates. Several clonal lineages of MRSA and methicillin-resistant S. epidermidis circulating in human hospitals and the community were found, suggesting that companion animals can become infected with and contribute to the

  1. Source mechanisms of persistent shallow earthquakes during eruptive and non-eruptive periods between 1981 and 2011 at Mount St. Helens, Washington

    Science.gov (United States)

    Lehto, Heather L.; Roman, Diana C.; Moran, Seth C.

    2013-01-01

    Shallow seismicity between 0 and 3-km depth has persisted at Mount St. Helens, Washington (MSH) during both eruptive and non-eruptive periods for at least the past thirty years. In this study we investigate the source mechanisms of shallow volcano-tectonic (VT) earthquakes at MSH by calculating high-quality hypocenter locations and fault plane solutions (FPS) for all VT events recorded during two eruptive periods (1981–1986 and 2004–2008) and two non-eruptive periods (1987–2004 and 2008–2011). FPS show a mixture of normal, reverse, and strike-slip faulting during all periods, with a sharp increase in strike-slip faulting observed in 1987–1997 and an increase in normal faulting in 1998–2004. FPS P-axis orientations show a ~ 90° rotation with respect to regional σ1 (N23°E) during 1981–1986 and 2004–2008, bimodal orientations (~ N-S and ~ E-W) during 1987–2004, and bimodal orientations at ~ N-E and ~ S-W from 2008–2011. We interpret these orientations to likely be due to pressurization accompanying the shallow intrusion and subsequent eruption of magma as domes during 1981–1986 and 2004–2008 and the buildup of pore pressure beneath a seismogenic volume (located at 0–1 km) with a smaller component due to the buildup of tectonic forces during 1987–2004 and 2008–2011.

  2. A new mechanism for periodic bursting of the recirculation region in the flow through a sudden expansion in a circular pipe

    Science.gov (United States)

    Lebon, Benoit; Nguyen, Minh Quan; Peixinho, Jorge; Shadloo, Mostafa Safdari; Hadjadj, Abdellah

    2018-03-01

    We report the results of a combined experimental and numerical study of specific finite-amplitude disturbances for transition to turbulence in the flow through a circular pipe with a sudden expansion. The critical amplitude thresholds for localized turbulent patch downstream of the expansion scale with the Reynolds number with a power law exponent of -2.3 for experiments and -2.8 for simulations. A new mechanism for the periodic bursting of the recirculation region is uncovered where the asymmetric recirculation flow develops a periodic dynamics: a secondary recirculation breaks the symmetry along the pipe wall and bursts into localized turbulence, which travels downstream and relaminarises. Flow visualizations show a simple flow pattern of three waves forming, growing, and bursting.

  3. Bamboo-like 3C-SiC nanowires with periodical fluctuating diameter: Homogeneous synthesis, synergistic growth mechanism, and their luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Meng; Zhao, Jian [School of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province 266061 (China); Li, Zhenjiang, E-mail: zhenjiangli@qust.edu.cn [School of Sino-German Science and Technology, Qingdao University of Science and Technology, Qingdao 266061, China (China); Yu, Hongyuan [School of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province 266061 (China); Wang, Yaqi [School of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province 266042 (China); Meng, Alan, E-mail: alanmengqust@163.com [School of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province 266042 (China); Li, Qingdang [School of Sino-German Science and Technology, Qingdao University of Science and Technology, Qingdao 266061, China (China)

    2016-11-15

    Herein, bamboo-like 3C-SiC nanowires have been successfully fabricated on homogeneous 6H-SiC substrate by a simple chemical vapor reaction (CVR) approach. The obtained 3C-SiC nanostructure with periodical fluctuating diameter, is composed of two alternating structure units, the typical normal-sized stem segment with perfect crystallinity and obvious projecting nodes segment having high-density stacking faults. The formation of the interesting morphology is significantly subjected to the peculiar growth condition provided by the homogeneous substrate as well as the varying growth elastic energy. Furthermore, the photoluminescence (PL) performance measured on the bamboo-like SiC nanowire shows an intensive emission peaks centered at 451 nm and 467 nm, which has been expected to make a positive progress toward the optical application of the SiC-based one-dimensional (1D) nanostructures, such as light emission diode (LED). - Graphical abstract: Based on the synergistic growth mechanism from homogeneous substrate and elastic energy, bamboo-like 3C-SiC nanowires with periodically fluctuating diameter have been synthesized on 6H-SiC. The blue-violet light emission properties of the bamboo-like nanowires have also been investigated for exploring their peculiar optical application. - Highlights: • Bamboo-like 3C-SiC nanowires with periodically fluctuating diameter have been synthesized on 6H-SiC. • A synergistic growth mechanism from homogeneous substrate and elastic energy has been proposed firstly. • The blue-violet light emission properties of the products displayed peculiar optical application.

  4. Bamboo-like 3C-SiC nanowires with periodical fluctuating diameter: Homogeneous synthesis, synergistic growth mechanism, and their luminescence properties

    International Nuclear Information System (INIS)

    Zhang, Meng; Zhao, Jian; Li, Zhenjiang; Yu, Hongyuan; Wang, Yaqi; Meng, Alan; Li, Qingdang

    2016-01-01

    Herein, bamboo-like 3C-SiC nanowires have been successfully fabricated on homogeneous 6H-SiC substrate by a simple chemical vapor reaction (CVR) approach. The obtained 3C-SiC nanostructure with periodical fluctuating diameter, is composed of two alternating structure units, the typical normal-sized stem segment with perfect crystallinity and obvious projecting nodes segment having high-density stacking faults. The formation of the interesting morphology is significantly subjected to the peculiar growth condition provided by the homogeneous substrate as well as the varying growth elastic energy. Furthermore, the photoluminescence (PL) performance measured on the bamboo-like SiC nanowire shows an intensive emission peaks centered at 451 nm and 467 nm, which has been expected to make a positive progress toward the optical application of the SiC-based one-dimensional (1D) nanostructures, such as light emission diode (LED). - Graphical abstract: Based on the synergistic growth mechanism from homogeneous substrate and elastic energy, bamboo-like 3C-SiC nanowires with periodically fluctuating diameter have been synthesized on 6H-SiC. The blue-violet light emission properties of the bamboo-like nanowires have also been investigated for exploring their peculiar optical application. - Highlights: • Bamboo-like 3C-SiC nanowires with periodically fluctuating diameter have been synthesized on 6H-SiC. • A synergistic growth mechanism from homogeneous substrate and elastic energy has been proposed firstly. • The blue-violet light emission properties of the products displayed peculiar optical application.

  5. que morreram de tétano neonatal em minas gerais (1997-2002

    Directory of Open Access Journals (Sweden)

    Lúcio José Vieira

    2006-01-01

    Full Text Available La finalidad de este artículo fue comprender, através del discurso de 19 madres de niños que murieron a consecuencia del tétanos neonatal en el Estado de Minas Gerais, Brasil, las representaciones sobre los medios de prevención de la enfermedad, destacándose la manera como fue cuidado el cordón umbilical. Datos secundarios, obtenidos en la Tarjeta de la Mujer Embarazada y en las Tarjetas de Notificación, fueron utilizados con miras a una mejor comprensión de los discursos de las entrevistadas. La metodología adoptada fue de naturaleza cuali-cuantitativa con enfoque en las representaciones sociales sobre la experiencia de la enfermedad. Para el análisis de las entrevistas fue utilizado el instrumento “discurso del sujeto colectivo”. Se observó la presencia de la creencia popular sobre los cuidados con el cordón umbilical y la deficiencia de los servicios en el proceso de la educación para la salud. Es urgente programar esfuerzos estratégicos específicos, dirigidos hacia la capacitación de parteras y profesionales de la salud, incrementar servicios de prenatal y ampliar la cobertura de vacunación, principalmente, en las regiones de donde provienen los casos de la investigación, contribuyendo asi para la eliminación de la enfermedad.

  6. Avaliação do projeto Cédula da Terra (1997-2002

    Directory of Open Access Journals (Sweden)

    João Márcio Mendes Pereira

    2012-08-01

    Full Text Available O artigo avalia o projeto-piloto Cédula da Terra, inspirado no modelo de "reforma agrária assistida pelo mercado" do Banco Mundial, implementado a partir de 1994 sob formatos diferenciados, em países marcados por graves problemas agrários e fortes tensões sociais no campo, como Colômbia, África do Sul, Guatemala e Filipinas. No Brasil, o Cédula foi implantado em cinco Estados da federação e foi aclamado pelo Banco como uma experiência exitosa e exemplar. A partir dele surgiram outros programas similares em maior escala. O artigo interroga se o diagnóstico do Banco Mundial de fato se justifica e se o Cédula constituiu mesmo uma referência viável a ser replicada em maior escala no Brasil.The article evaluates the pilot-project Cédula da Terra, inspired on the "market-assisted land reform" model of the World Bank, implemented since 1994 under various formats in countries marked by the deep agrarian problems and strong social tensions in the countryside, such as Colombia, South Africa, Guatemala and the Philippines. In Brazil, the project was implemented in five states of the federation and was acclaimed by the Bank as a successful and textbook experience. From it were developed other similar programs on a large scale. The article questions if the World Bank's diagnostics are indeed justifiable and if the Cédula da Terra was really a viable reference to be replicated in Brazil in larger scale.

  7. Resistencia antimicrobiana de Salmonella, Shigella y Vibrio cholerae: Perú 1997-2002

    Directory of Open Access Journals (Sweden)

    Isabel Arias B

    2004-10-01

    Full Text Available La resistencia a los antimicrobianos es un problema de salud pública, en este caso se presentan los resultados de la resistencia antimicrobiana de Salmonella, Shigella y Vibrio cholerae entre los años 1997 y 2002 de las cepas confirmadas por el Instituto Nacional de Salud, procedentes de los laboratorios referenciales regionales de las diferentes direcciones de salud del Perú. La confirmación se realizó mediante bioquímica y serotipificación; para las pruebas de sensibilidad se utilizó el método de disco difusión. Se evaluaron un total de 542 cepas de Salmonella, 1034 de Shigella y 603 de Vibrio cholerae. La resistencia de Shigella frente a ampicilina muestra un promedio de 74,4% durante los 6 años; cloramfenicol con 65,9 %, cotrimoxazol con 72,2 %. En Salmonella se observa un promedio de 3,46 % para ampicilina; 2,83 % para cloranfenicol; en gentamicina 3,9 % y cotrimoxazol 1,1. V. Cholerae entre 1997 y 1999 mostraron promedios de resistencia de 19 % a cotrimoxazol, 12,1 % a tetraciclina y 10,2 % a ampicilina. A partir del año 2000, no se reportaron casos, por lo que se recibieron pocas cepas de esta especie. Se evidencia el problema de resistencia de Shigella frente a ampicilina, cloramfenicol y cotrimoxazol.

  8. Source mechanism of small long-period events at Mount St. Helens in July 2005 using template matching, phase-weighted stacking, and full-waveform inversion

    Science.gov (United States)

    Matoza, Robin S.; Chouet, Bernard A.; Dawson, Phillip B.; Shearer, Peter M.; Haney, Matthew M.; Waite, Gregory P.; Moran, Seth C.; Mikesell, T. Dylan

    2015-01-01

    Long-period (LP, 0.5-5 Hz) seismicity, observed at volcanoes worldwide, is a recognized signature of unrest and eruption. Cyclic LP “drumbeating” was the characteristic seismicity accompanying the sustained dome-building phase of the 2004–2008 eruption of Mount St. Helens (MSH), WA. However, together with the LP drumbeating was a near-continuous, randomly occurring series of tiny LP seismic events (LP “subevents”), which may hold important additional information on the mechanism of seismogenesis at restless volcanoes. We employ template matching, phase-weighted stacking, and full-waveform inversion to image the source mechanism of one multiplet of these LP subevents at MSH in July 2005. The signal-to-noise ratios of the individual events are too low to produce reliable waveform-inversion results, but the events are repetitive and can be stacked. We apply network-based template matching to 8 days of continuous velocity waveform data from 29 June to 7 July 2005 using a master event to detect 822 network triggers. We stack waveforms for 359 high-quality triggers at each station and component, using a combination of linear and phase-weighted stacking to produce clean stacks for use in waveform inversion. The derived source mechanism pointsto the volumetric oscillation (~10 m3) of a subhorizontal crack located at shallow depth (~30 m) in an area to the south of Crater Glacier in the southern portion of the breached MSH crater. A possible excitation mechanism is the sudden condensation of metastable steam from a shallow pressurized hydrothermal system as it encounters cool meteoric water in the outer parts of the edifice, perhaps supplied from snow melt.

  9. Potential of acute phase proteins as predictor of postpartum uterine infections during transition period and its regulatory mechanism in dairy cattle

    Directory of Open Access Journals (Sweden)

    A. Manimaran

    2016-01-01

    Full Text Available Among the various systemic reactions against infection or injury, the acute phase response is the cascade of reaction and mostly coordinated by cytokines-mediated acute phase proteins (APPs production. Since APPs are sensitive innate immune molecules, they are useful for early detection of inflammation in bovines and believed to be better discriminators than routine hematological parameters. Therefore, the possibility of using APPs as a diagnostic and prognostic marker of inflammation in major bovine health disorders including postpartum uterine infection has been explored by many workers. In this review, we discussed specifically importance of postpartum uterine infection, the role of energy balance in uterine infections and potential of APPs as a predictor of postpartum uterine infections during the transition period and its regulatory mechanism in dairy cattle.

  10. Methanol to olefin Conversion on HSAPO-34 zeolite from periodic density functional theory calculations: a complete cycle of side chain hydrocarbon pool mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.M.; Wang, Y.D.; Xie, Z.K.; Liu, Z.P. [SINOPEC, Shanghai (China)

    2009-03-15

    For its unique position in the coal chemical industry, the methanol to olefin (MTO) reaction has been a hot topic in zeolite catalysis. Due to the complexities of catalyst structure and reaction networks, many questions such as how the olefin chain is built from methanol remain elusive. On the basis of periodic density functional theory calculations, this work establishes the first complete catalytic cycle for MTO reaction via hexamethylbenzene (HMB) trapped in HSAPO-34 zeolite based on the so-called side chain hydrocarbon pool mechanism. The cycle starts from the methylation of HMB that leads to heptamethylbenzenium ion (heptaMB{sup +}) intermediate. This is then followed by the growth of side chain via repeated deprotonation of benzenium ions and methylation of the exocyclic double bond. Ethene and propene can finally be released from the side ethyl and isopropyl groups of benzenium ions by deprotonation and subsequent protonation steps. We demonstrate that (i) HMB/HSAPO-34 only yields propene as the primary product based on the side chain hydrocarbon pool mechanism and (ii) an indirect proton-shift step mediated by water that is always available in the system is energetically more favorable than the traditionally regarded internal hydrogen-shift step. Finally, the implications of our results toward understanding the effect of acidity of zeolite on MTO activity are also discussed.

  11. Circadian Clock Synchronization of the Cell Cycle in Zebrafish Occurs through a Gating Mechanism Rather Than a Period-phase Locking Process.

    Science.gov (United States)

    Laranjeiro, Ricardo; Tamai, T Katherine; Letton, William; Hamilton, Noémie; Whitmore, David

    2018-04-01

    Studies from a number of model systems have shown that the circadian clock controls expression of key cell cycle checkpoints, thus providing permissive or inhibitory windows in which specific cell cycle events can occur. However, a major question remains: Is the clock actually regulating the cell cycle through such a gating mechanism or, alternatively, is there a coupling process that controls the speed of cell cycle progression? Using our light-responsive zebrafish cell lines, we address this issue directly by synchronizing the cell cycle in culture simply by changing the entraining light-dark (LD) cycle in the incubator without the need for pharmacological intervention. Our results show that the cell cycle rapidly reentrains to a shifted LD cycle within 36 h, with changes in p21 expression and subsequent S phase timing occurring within the first few hours of resetting. Reentrainment of mitosis appears to lag S phase resetting by 1 circadian cycle. The range of entrainment of the zebrafish clock to differing LD cycles is large, from 16 to 32 hour periods. We exploited this feature to explore cell cycle entrainment at both the population and single cell levels. At the population level, cell cycle length is shortened or lengthened under corresponding T-cycles, suggesting that a 1:1 coupling mechanism is capable of either speeding up or slowing down the cell cycle. However, analysis at the single cell level reveals that this, in fact, is not true and that a gating mechanism is the fundamental method of timed cell cycle regulation in zebrafish. Cell cycle length at the single cell level is virtually unaltered with varying T-cycles.

  12. The Periodic Pyramid

    Science.gov (United States)

    Hennigan, Jennifer N.; Grubbs, W. Tandy

    2013-01-01

    The chemical elements present in the modern periodic table are arranged in terms of atomic numbers and chemical periodicity. Periodicity arises from quantum mechanical limitations on how many electrons can occupy various shells and subshells of an atom. The shell model of the atom predicts that a maximum of 2, 8, 18, and 32 electrons can occupy…

  13. Influence of temperature histories during reactor startup periods on microstructural evolution and mechanical properties of austenitic stainless steel irradiated with neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kasahara, Shigeki, E-mail: kasahara.shigeki@jaea.go.jp [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kitsunai, Yuji [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Chimi, Yasuhiro [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chatani, Kazuhiro; Koshiishi, Masato [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Nishiyama, Yutaka [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

    2016-11-15

    This paper addresses influence of two different temperature profiles during startup periods in the Japan Materials Testing Reactor and a boiling water reactor upon microstructural evolution and mechanical properties of austenitic stainless steel irradiated with neutrons to about 1 dpa and 3 dpa. One of the temperature profiles was that the specimens experienced neutron irradiation in both reactors, under which the irradiation temperature transiently increased to 290 °C from room temperature with increasing reactor power during reactor startup periods. Another was that the specimens were pre-heated to about 150 °C prior to the irradiation to suppress the transient temperature increase. Tensile tests at 290 °C and Vickers hardness tests at room temperature were carried out, and their microstructures were observed by FEG-TEM. Difference of the temperature profiles was observed obviously in interstitial cluster formation, in particular, growth of Frank loops. Although influence of neutron irradiation involving transient temperature increase to 290 °C from room temperature on the yield strength and the Vickers hardness is buried in the trend curves of existing data, the influence was also found certainly in increment of in yield strength, existence of modest yield drop, and loss of strain hardening capacity and ductility. As a result, Frank loops, which were observed in austenitic stainless steel irradiated at doses of 1 dpa or more, seemed to have important implications regarding the interpretation of not irradiation hardening, but deformation of the austenitic stainless steel.

  14. Repeated touch and needle-prick stimulation in the neonatal period increases the baseline mechanical sensitivity and postinjury hypersensitivity of adult spinal sensory neurons.

    Science.gov (United States)

    van den Hoogen, Nynke J; Patijn, Jacob; Tibboel, Dick; Joosten, Bert A; Fitzgerald, Maria; Kwok, Charlie H T

    2018-03-08

    Noxious stimulation at critical stages of development has long-term consequences on somatosensory processing in later life, but it is not known whether this developmental plasticity is restricted to nociceptive pathways. Here, we investigate the effect of repeated neonatal noxious or innocuous hind paw stimulation on adult spinal dorsal horn cutaneous mechanical sensitivity. Neonatal Sprague-Dawley rats of both sexes received 4 unilateral left hind paw needle pricks (NPs, n = 13) or 4 tactile (cotton swab touch) stimuli, per day (TC, n = 11) for the first 7 days of life. Control pups were left undisturbed (n = 17). When adult (6-8 weeks), lumbar wide-dynamic-range neuron activity in laminae III-V was recorded using in vivo extracellular single-unit electrophysiology. Spike activity evoked by cutaneous dynamic tactile (brush), pinch and punctate (von Frey hair) stimulation, and plantar receptive field areas were recorded, at baseline and 2 and 5 days after left plantar hind paw incision. Baseline brush receptive fields, von Frey hair, and pinch sensitivity were significantly enhanced in adult NP and TC animals compared with undisturbed controls, although effects were greatest in NP rats. After incision, injury sensitivity of adult wide-dynamic-range neurons to both noxious and dynamic tactile hypersensitivity was significantly greater in NP animals compared with TC and undisturbed controls. We conclude that both repeated touch and needle-prick stimulation in the neonatal period can alter adult spinal sensory neuron sensitivity to both innocuous and noxious mechanical stimulation. Thus, spinal sensory circuits underlying touch and pain processing are shaped by a range of early-life somatosensory experiences.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

  15. High-Precision Locations and the Stress Field from Instrumental Seismicity, Moment Tensors, and Short-Period Mechanisms through the Mina Deflection, Central Walker Lane

    Science.gov (United States)

    Ruhl, C. J.; Smith, K. D.

    2012-12-01

    well as available and developed short-period focal mechanisms are compiled to evaluate the stress field to assess mechanisms of slip accommodation. Based on the complex distribution of fault orientations, the stress field varies locally northward from the SWL throughout the MD; however, in many cases, fault plane alignments can be isolated from high-precision locations, providing better constraints on stress and slip orientations.

  16. A Novel Two-Tier Cooperative Caching Mechanism for the Optimization of Multi-Attribute Periodic Queries in Wireless Sensor Networks

    Science.gov (United States)

    Zhou, ZhangBing; Zhao, Deng; Shu, Lei; Tsang, Kim-Fung

    2015-01-01

    Wireless sensor networks, serving as an important interface between physical environments and computational systems, have been used extensively for supporting domain applications, where multiple-attribute sensory data are queried from the network continuously and periodically. Usually, certain sensory data may not vary significantly within a certain time duration for certain applications. In this setting, sensory data gathered at a certain time slot can be used for answering concurrent queries and may be reused for answering the forthcoming queries when the variation of these data is within a certain threshold. To address this challenge, a popularity-based cooperative caching mechanism is proposed in this article, where the popularity of sensory data is calculated according to the queries issued in recent time slots. This popularity reflects the possibility that sensory data are interested in the forthcoming queries. Generally, sensory data with the highest popularity are cached at the sink node, while sensory data that may not be interested in the forthcoming queries are cached in the head nodes of divided grid cells. Leveraging these cooperatively cached sensory data, queries are answered through composing these two-tier cached data. Experimental evaluation shows that this approach can reduce the network communication cost significantly and increase the network capability. PMID:26131665

  17. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  18. Source mechanism of Vulcanian degassing at Popocatépetl Volcano, Mexico, determined from waveform inversions of very long period signals

    Science.gov (United States)

    Chouet, Bernard A.; Dawson, Phillip B.; Arciniega-Ceballos, Alejandra

    2005-01-01

    The source mechanism of very long period (VLP) signals accompanying volcanic degassing bursts at Popocatépetl is analyzed in the 15–70 s band by minimizing the residual error between data and synthetics calculated for a point source embedded in a homogeneous medium. The waveforms of two eruptions (23 April and 23 May 2000) representative of mild Vulcanian activity are well reproduced by our inversion, which takes into account volcano topography. The source centroid is positioned 1500 m below the western perimeter of the summit crater, and the modeled source is composed of a shallow dipping crack (sill with easterly dip of 10°) intersecting a steeply dipping crack (northeast striking dike dipping 83° northwest), whose surface extension bisects the vent. Both cracks undergo a similar sequence of inflation, deflation, and reinflation, reflecting a cycle of pressurization, depressurization, and repressurization within a time interval of 3–5 min. The largest moment release occurs in the sill, showing a maximum volume change of 500–1000 m3, pressure drop of 3–5 MPa, and amplitude of recovered pressure equal to 1.2 times the amplitude of the pressure drop. In contrast, the maximum volume change in the dike is less (200–300 m3), with a corresponding pressure drop of 1–2 MPa and pressure recovery equal to the pressure drop. Accompanying these volumetric sources are single-force components with magnitudes of 108 N, consistent with melt advection in response to pressure transients. The source time histories of the volumetric components of the source indicate that significant mass movement starts within the sill and triggers a mass movement response in the dike within a few seconds. Such source behavior is consistent with the opening of a pathway for escape of pent-up gases from slow pressurization of the sill driven by magma crystallization. The opening of this pathway and associated rapid evacuation of volcanic gases induces the pressure drop. Pressure

  19. Problem Periods

    Science.gov (United States)

    ... ovary syndrome. Read our information on PCOS for teens , and see your doctor if you think you may have PCOS. Major weight loss. Girls who have anorexia will often stop having periods. When to see ...

  20. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  1. Mechanisms of Plastic and Fracture Instabilities for Alloy Development of Fusion Materials. Final Project Report for period July 15, 1998 - July 14, 2003

    Energy Technology Data Exchange (ETDEWEB)

    Ghoniem, N. M.

    2003-07-14

    The main objective of this research was to develop new computational tools for the simulation and analysis of plasticity and fracture mechanisms of fusion materials, and to assist in planning and assessment of corresponding radiation experiments.

  2. Mechanisms of Plastic and Fracture Instabilities for Alloy Development of Fusion Materials. Final Project Report for period July 15, 1998 - July 14, 2003

    International Nuclear Information System (INIS)

    Ghoniem, N.M.

    2003-01-01

    The main objective of this research was to develop new computational tools for the simulation and analysis of plasticity and fracture mechanisms of fusion materials, and to assist in planning and assessment of corresponding radiation experiments

  3. Chemical mechanisms of /sup 60/Co transport in ground water from intermediate-level liquid waste trench 7: progress report for period ending June 30, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Means, J.L.; Crerar, D.A.; Duguid, J.O.

    1976-11-01

    A seep approximately 50 meters east of trench 7 within the ORNL restricted area contains /sup 60/Co in concentrations of 10/sup 4/ to 10/sup 6/ dpm/g in the soil and 10/sup 3/ dpm/ml in the water. Traces of /sup 125/Sb and various transuranics have also been detected in the soil. However, because the volume of water discharge from the seep is small, the total radionuclide contribution from the trench 7 area to White Oak Creek and the Clinch River is insignificant. The /sup 60/Co is transported in the ground-water from the trench to the seep as organic complexes and is absorbed by manganese oxides and to a lesser extent by iron sesquioxides in the shale and soil. In the absence of these organic complexing agents, /sup 60/Co mobilization would be negligible because the sediment absorption capacity for inorganic forms of /sup 60/Co is extremely high. The primary objective of this study has been to investigate /sup 60/Co transport and absorption mechanisms as observed in the study area. Because the organic complexing characteristics of transition metals and transuranics are similar, the mechanisms of /sup 60/Co transport determined in this study may also apply to plutonium and other alpha-emitters. Also the experimental and analytical methods employed in this study apply to the identification of other migrating radionuclide complexes from other disposal trenches and pits at ORNL. The increased knowledge of transport and adsorption mechanisms will provide insight into methods of controlling the movement of radionuclides from these and future disposal areas.

  4. Chemical mechanisms of 60Co transport in ground water from intermediate-level liquid waste trench 7: progress report for period ending June 30, 1975

    International Nuclear Information System (INIS)

    Means, J.L.; Crerar, D.A.; Duguid, J.O.

    1976-11-01

    A seep approximately 50 meters east of trench 7 within the ORNL restricted area contains 60 Co in concentrations of 10 4 to 10 6 dpm/g in the soil and 10 3 dpm/ml in the water. Traces of 125 Sb and various transuranics have also been detected in the soil. However, because the volume of water discharge from the seep is small, the total radionuclide contribution from the trench 7 area to White Oak Creek and the Clinch River is insignificant. The 60 Co is transported in the ground-water from the trench to the seep as organic complexes and is absorbed by manganese oxides and to a lesser extent by iron sesquioxides in the shale and soil. In the absence of these organic complexing agents, 60 Co mobilization would be negligible because the sediment absorption capacity for inorganic forms of 60 Co is extremely high. The primary objective of this study has been to investigate 60 Co transport and absorption mechanisms as observed in the study area. Because the organic complexing characteristics of transition metals and transuranics are similar, the mechanisms of 60 Co transport determined in this study may also apply to plutonium and other alpha-emitters. Also the experimental and analytical methods employed in this study apply to the identification of other migrating radionuclide complexes from other disposal trenches and pits at ORNL. The increased knowledge of transport and adsorption mechanisms will provide insight into methods of controlling the movement of radionuclides from these and future disposal areas

  5. The mechanism and theoretical basis of the management of intensity of the heat transfer control through periodic influences on the turbulent boundary layer

    Science.gov (United States)

    Kovalnogov, Vladislav N.; Fedorov, Ruslan V.; Khakhaleva, Larisa V.; Chukalin, Andrey V.; Bondarenko, Aleksandr A.; Kovrizhnykh, Evgeny N.

    2017-07-01

    Generalization of classical model of a displacement way on the transfer of heat exchange and mass exchange of a stream in the boundary layer, confirmed by the control action of the different nature, is undertaken. Here are given the results of numerical research which have allowed explaining the mechanism, to reveal efficiency and limits of various ways of management of intensity in exchange processes. The possibility of management of intensity in processes of a thermolysis and friction by use of the perforated surface with the damping cavities is analyzed.

  6. The Influence of Good Corporate Governance Mechanism on Earnings Management: Empirical Study in Indonesian Stock Exchange Listed Company for Periods of 2006-2010

    Directory of Open Access Journals (Sweden)

    Hermiyetti Hermiyetti

    2013-01-01

    Full Text Available The purpose of this research is to examine the influence of good corporate governance mechanism about earnings management in companies listed in Indonesian Stock Exchange during 2006 to 2010. The independent variables include the size of commissioner board, independent commissioner board percentage, size of audit committee, and commissioner meeting frequency. The dependent variable is earnings management which is measured by discretionary revenue model (Stubben, 2010. Size of company is used as the control variable in this research. The population of this research is 465 samples from companies listed at Indonesian Stock Exchange during 2006 to 2010. The sampling method used in this research is purposive sampling method. In addition, the data analysis method used is regression analysis and descriptive statistics. The result of this research indicates that the mechanism of good corporate governance which is represented by the size of commissioner board, independent commissioner board percentage, size of audit committee, and commissioner meeting frequency do not have any significant impact on earnings management. However, the result shows that company size gave positive influence toward earning management. Keywords: Good corporate governance, size of commissioner board, independent commissioner board percentage, size of audit committee, commissioner meeting frequency, earnings management

  7. Contingent capture of visual-spatial attention depends on capacity-limited central mechanisms: evidence from human electrophysiology and the psychological refractory period.

    Science.gov (United States)

    Brisson, Benoit; Leblanc, Emilie; Jolicoeur, Pierre

    2009-02-01

    It has recently been demonstrated that a lateralized distractor that matches the individual's top-down control settings elicits an N2pc wave, an electrophysiological index of the focus of visual-spatial attention, indicating that contingent capture has a visual-spatial locus. Here, we investigated whether contingent capture required capacity-limited central resources by incorporating a contingent capture task as the second task of a psychological refractory period (PRP) dual-task paradigm. The N2pc was used to monitor where observers were attending while they performed concurrent central processing known to cause the PRP effect. The N2pc elicited by the lateralized distractor that matched the top-down control settings was attenuated in high concurrent central load conditions, indicating that although involuntary, the deployment of visual-spatial attention occurring during contingent capture depends on capacity-limited central resources.

  8. The investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis: Final report for period April 1, 1972-June 30, 1987

    International Nuclear Information System (INIS)

    Grossweiner, L.I.

    1987-07-01

    Laser flash was employed to investigate initial photolysis mechanisms in enzymes and constituent aromatic amino acids. The key role of photoionization and solvated electron generation was demonstrated. The photochemistry of furocoumarins employed for phototherapy of skin diseases was investigated, emphasizing the production and subsequent reactions of singlet molecular oxygen. The photochemistry of porphyrins employed for photodynamic therapy of malignant tumors was studied, emphasizing photosensitization of model membranes, liposomes and resealed red blood cell membranes. Photosensitization in light-scattering media was investigated in a tissue model, consisting of polystyrene microspheres in an aqueous dye solution and analyzed with the diffusion approximation to radiative transfer. The diffusion approximation was employed to develop a dosimetry model for photodynamic therapy

  9. Computational and experimental fluid mechanics. Draft version of annex to final report for period January 1st 1993 to December 31st 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    The general purpose of the program has been the development of efficient algorithms, their implementation in codes of Computational Fluid Mechanics (CFD), and the experimental verification of these codes. Flows of both fundamental and applied nature has been investigated, including flows in industrial process equipment, about aerodynamics structures and ships, and flows over bed forms of importance for sediment transport. The experimental work has included the development of improved techniques, emphasizing optical methods. The objectives were realized through a coordinated experimental and theoretical/computation research program, organized in 6 specific projects: 1. CFD-methods and algorithms. 2. Special element simulation of ultrafiltration. 3. Turbulent swirling flows; 4. Near-wall models of turbulence and development of experimental techniques. 5. Flow over bed forms. 6. Flow past ship hull. (au)

  10. [Difference of anti-fracture mechanical characteristics between lateral-root branches and adjacent upper straight roots of four plant species in vigorous growth period].

    Science.gov (United States)

    Liu, Peng-fei; Liu, Jing; Zhu, Hong-hui; Zhang, Xin; Zhang, Ge; Li, You-fang; Su, Yu; Wang, Chen-jia

    2016-01-01

    Taking four plant species, Caragana korshinskii, Salix psammophila, Hippophae rhamnides and Artemisia sphaerocephala, which were 3-4 years old and in vigorous growth period, as test materials, the anti-fracture forces of lateral-root branches and adjacent upper straight roots were measured with the self-made fixture and the instrument of TY 8000. The lateral-root branches were vital and the diameters were 1-4 mm. The results showed that the anti-fracture force and anti-fracture strength of lateral-root branches were lesser than those of the adjacent upper straight roots even though the average diameter of lateral-root branches was greater. The ratios of anti-fracture strength of lateral-root branches to the adjacent upper straight roots were 71.5% for C. korshinskii, 62.9% for S. psammophila, 45.4% for H. rhamnides and 35.4% for A. sphaerocephala. For the four plants, the anti-fracture force positively correlated with the diameter in a power function, while the anti-fracture strength negatively correlated with diameter in a power function. The anti-fracture strengths of lateral-root branches and adjacent upper straight roots for the four species followed the sequence of C. korshinskii (33.66 and 47.06 MPa) > S. psammophila (17.31 and 27.54 MPa) > H. rhamnides (3.97 and 8.75 MPa) > A. sphaerphala (2.18 and 6.15 MPa).

  11. Focal Mechanism of a Catastrophic Earthquake of the Last Rococo Period (1783) in Southern Italy Retrieved by Inverting Historical Information on Damage

    Science.gov (United States)

    Sirovich, L.; Pettenati, F.

    2007-05-01

    Using geophysical inversion to discover the fault source of a blind earthquake, that took place before the invention of the seismograph, seemed impossible. We demonstrated that sometimes it is possible using our simplified KF model (Sirovich, 1996) through automatic genetic inversion (Gentile et al., 2004 in BSSA; Sirovich and Pettenati, 2004 in JGR), and determined it conclusively by treating the Coalinga 1983, Loma Prieta 1989, and Northridge 1994 earthquakes (Pettenati and Sirovich, 2007 in BSSA). KF is able to simulate the body-wave radiation from a linear source, and eleven source parameters are retrieved: the three nucleation coordinates, the fault-plane solution, the seismic moment, the rupture velocities and lengths along-strike and anti-strike, the shear wave velocity in the half-space. To find the minima on the hypersurface of the residuals in the multi-parameter model space, we use a genetic process with niching since we have already shown that the problem is bimodal for pure dip-slip mechanisms. The objective function of the nonlinear inversion is the sum of the squared residuals (calculated-minus-observed intensity at all sites). Here, we use the very good intensity data provided in the MCS scale by the INGV of Italy for the M 6.9 earthquake of Feb. 5, 1783 (see the Italian intensity data bank on http:emidius.mi.ingv.it/DOM/consultazione.html). The data of 1783 were created by seismologists and historians who interpreted the reports of the time and many other historical sources. Given the limitations of the KF approach, we limited our inversion to a square area of 200 by 200 km around the most heavily damaged zone. 341 surveyed towns and hamlets received intensity degrees by INGV (we discarded 6 of them as statistical outliers according to the classical Chauvenet method). Thus, 335 data were inverted. The match between experimental and synthetic isoseismals is really noteworthy. The found mechanism is almost pure dip-slip and, thus, the problem is

  12. Directional wave and temperature data from six buoys at Diablo Canyon, CA, 1997-2002 (NODC Accession 0000761)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Data Information Program (CDIP) is an extensive network for monitoring waves along the coastlines of the United States, with a strong emphasis on our...

  13. Family size, cognitive outcomes, and familial interaction in stable, two-parent families: United States, 1997-2002.

    Science.gov (United States)

    Sandberg, John; Rafail, Patrick

    2014-10-01

    Measures of children's time use, particularly with parents and siblings, are used to evaluate three hypotheses in relation to the vocabulary and mathematical skills development: (1) the resource dilution hypothesis, which argues that parental and household resources are diluted in larger families; (2) the confluence hypothesis, which suggests that the intellectual milieu of families is lowered with additional children; and (3) the admixture ("no effect") hypothesis, which suggests that the negative relationship between family size and achievement is an artifact of cross-sectional research resulting from unobserved heterogeneity. Each hypothesis is tested using within-child estimates of change in cognitive scores over time with the addition of new children to families.

  14. La nueva comunicación eclesial a la luz de los documentos magisteriales del lustro 1997-2002

    Directory of Open Access Journals (Sweden)

    Hugo Tagle

    2003-01-01

    Full Text Available RESUMEN Las afirmaciones sobre un cambio epocal a raíz de la explosión de los medios de comunicación no exageran. El fenómeno descrito por el teórico de las comunicaciones McLuhan sobre la "aldea global" hace algunos decenios se hacen día a día realidad. No nos extraña poder ver el mundial de fútbol en Corea, los juegos olímpicos en Suiza o que el Papa le hable a mil millones de personas simultáneamente en su mensaje de Navidad. Podemos trasladar una biblioteca entera de un país a otro o "bajarla" de Internet en cosa de minutos. Los cambios comunicacionales son de tal envergadura que se habla de una revolución como la que experimentó la humanidad a fines del siglo XIX con la revolución industrial. Y eso que nos encontramos recién en sus comienzos(22. Los continuos cambios en este campo de las ciencias tan gravitante ha gatillado una serie de documentos del magisterio, donde la Iglesia ha tomado postura ante ellos y dado valiosas orientaciones sobre su uso y validez. Sobre estos aspectos trataremos en las próximas páginas.The assertions about an era change caused by the explosion of the media, are not an exaggeration. The phenomenon described some decades ago by the media theorist McLuhan on the `global village' are a reality today. We are no longer surprised to watch the football world cup in Korea, the Olympic games in Switzerland or the Pope giving his Christmas message to millions of people simultaneously. In the Internet, we can `download' whole libraries from other countries in a matter of minutes. The changes in communications are such, that they are said to match the revolution the humanity went through at the end of the XIX century with the Industrial Revolution. Nevertheless, these changes are only in their early stages. The ongoing shifts in this field have encouraged the Magisterium to publish a series of documents. In them, the Church has adopted a position and has given valuable orientations on their use and validity. These issues will be dealt with in this article.

  15. Hepatitis A virus strains circulating during 1997-2015 in Campania, a Southern Italy region with periodic outbreaks.

    Science.gov (United States)

    Costantino, Angela; Coppola, Nicola; Spada, Enea; Bruni, Roberto; Taffon, Stefania; Equestre, Michele; Marcantonio, Cinzia; Sagnelli, Caterina; Dell'Isola, Chiara; Tosone, Grazia; Mascolo, Silvia; Sagnelli, Evangelista; Ciccaglione, Anna Rita

    2017-11-01

    In Italy, the incidence of hepatitis A has progressively declined over the last 30 years, though not homogeneously throughout the country. In Campania, Southern Italy, high annual incidence rates have been reported and several periodic outbreaks have occurred. To investigate the phylogenetic and epidemiologic relationships among HAV strains circulating in Campania over the period 1997-2015, 87 hepatitis A cases were investigated. The most frequent risk factor was the consumption of raw/undercooked shellfish (75/87, 86.2%). During 1997-2002 most viral strains were subtype IA (16/23, 70%); the phylogenetic pattern suggests that the incidence peaks observed in 2000-2001 had likely been caused by multiple strains. During a large 2004 outbreak, almost all viral variants were subtype IB (38/41, 93%); most of them (22/38, 58%) were recognized to be one of two main strains (differing for just a single nucleotide), the remaining sequences were strictly related variants. In 2014/2015, only IA strains were observed; two phylogenetically related but distinct strains were responsible, respectively, for a small cluster in 2014 and an outbreak in 2015. In each outbreak, several strains unrelated to those responsible for most cases were detected in a minority of patients, documenting a background of sporadic cases occurring even in the course of outbreaks; some of them proved to be identical to strains detected 11-14 years previously. Overall, the data suggest that several related and unrelated HAV strains have endemically circulated over the last 15 years in Campania, with some strains gaining epidemic transmission likely because of a local combination of multiple factors, including inadequate waste water purification and dietary habits. © 2017 Wiley Periodicals, Inc.

  16. [Two traditions in the scientific learning of the world. A case study of creation and reception of quantum mechanics over the period 1925-1927, on the bases of discussion between Werner Heisenberg and Albert Einstein].

    Science.gov (United States)

    Krajniak, Wiktor

    2014-01-01

    The purpose of this article is the analyses of discussion between Albert Einstein and Werner Heisenberg in the period 1925-1927. Their disputes, relating to the sources of scientific knowledge, its methods and the value of knowledge acquired in this way, are part of the characteristic for the European science discourse between rationalism and empirism. On the basis of some sources and literature on the subject, the epistemological positions of both scholars in the period were reconstructed. This episode, yet poorly known, is a unique example of scientific disputes, whose range covers a broad spectrum of methodological problems associated with the historical development of science. The conducted analysis sheds some light on the source of popularity of logical empirism in the first half of the 20th century. A particular emphasis is placed on the impact of the neopositivist ideas which reflect Heisenberg's research program, being the starting point for the Copenhagen interpretation of quantum mechanics. The main assumption of logical empirism, concerning acquisition of scientific knowledge only by means of empirical procedures and logical analysis of the language of science, in view of the voiced by Einstein arguments, bears little relationship with actual testing practices in the historical aspect of the development of science. The criticism of Heisenberg's program, carried out by Einstein, provided arguments for the main critics of the neopositivist ideal and contributed to the bankruptcy of the idea of logical empirism, thereby starting a period of critical rationalism prosperity, arising from criticism of neopositivism and alluding to Einstein's ideas.

  17. Polysheroidal periodic functions

    International Nuclear Information System (INIS)

    Truskova, N.F.

    1985-01-01

    Separation of variables in the Helmholtz N-dimensional (N≥4) equation in polyspheroidal coordinate systems leads to the necessity of solving equations going over into equations for polyspheroidal periodic functions used for solving the two-centre problem in quantum mechanics, the three-body problem with Coulomb interaction, etc. For these functions the expansions are derived in terms of the Jacobi polynomials and Bessel functions. Their basic properties, asymptotics are considered. The algorithm of their computer calculations is developed. The results of numerical calculations are given

  18. Evolution of periodicity in periodical cicadas.

    Science.gov (United States)

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  19. Effects of heat treatment on the morphology of long-period stacking ordered phase and the corresponding mechanical properties of Mg–9Gd–xEr–1.6Zn–0.6Zr magnesium alloys

    International Nuclear Information System (INIS)

    Wang, Jingfeng; Song, Pengfei; Huang, Song; Pan, Fusheng

    2013-01-01

    This study investigates the effects of heat treatment on the morphology of long-period stacking ordered phase (LPSO) and the corresponding mechanical properties of Mg–9Gd–xEr–1.6Zn–0.6Zr (1–4 wt%) using optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, transmission electron microscopy, and tensile tests. The microstructure analysis of the as cast alloys showed that the volume fraction of the (Mg, Zn) 3 (Gd, Er) phase increased with increasing Er content. The (Mg, Zn) 3 (Gd, Er) phase in grain boundaries transformed into the 14H-LPSO phase Mg 12 Zn(Gd, Er) after heat treatment between 400 °C and 515 °C. The bulk shaped LPSO phases distributed along the grain boundaries produced isometric crystal grains in and enhanced the ductility of the as-extruded alloys. However, the lamellar LPSO phases precipitating in the grain interior induced strip-shaped grains in and improved the strength of the as-extruded alloys

  20. Minimum period and the gap in periods of Cataclysmic binaries

    International Nuclear Information System (INIS)

    Paczynski, B.; Sienkiewicz, R.

    1983-01-01

    The 81 minute cutoff to the orbital periods of hydrogen-rich cataclysmic binaries is consistent with evolution of those systems being dominated by angular momentum losses due to gravitational radiation. Unfortunately, many uncertainties, mainly poorly known atmospheric opacities below 2000 K, make is physically impossible to verify the quadrupole formula for gravitational radiation by using the observed cutoff at 81 minutes. The upper boundary of the gap in orbital periods observed at about 3 hours is almost certainly due to enhanced angular momentum losses from cataclysmic binaries which have longer periods. The physical mechanism of those losses is not identified, but a possible importance of stellar winds is pointed out. The lower boundary of the gap may be explained with the oldest cataclysmic binaries, whose periods evolved past the minimum at 81 minutes and reached the value of 2 hours within about 12 x 10 9 years after the binary had formed. Those binaries should have secondary components of only 0.02 solar masses, and their periods could be used to estimate ages of the oldest cataclysmic stars, and presumably the age of Galaxy. An alternative explanation for the gap requires that binaries should be detached while crossing the gap. A possible mechanism for this phenomenon is discussed. It requires the secondary components to be about 0.2 solar masses in the binaries just below the gap

  1. Evolution of aerosol chemistry in Xi'an, inland China, during the dust storm period of 2013 - Part 1: Sources, chemical forms and formation mechanisms of nitrate and sulfate

    Science.gov (United States)

    Wang, G. H.; Cheng, C. L.; Huang, Y.; Tao, J.; Ren, Y. Q.; Wu, F.; Meng, J. J.; Li, J. J.; Cheng, Y. T.; Cao, J. J.; Liu, S. X.; Zhang, T.; Zhang, R.; Chen, Y. B.

    2014-11-01

    A total suspended particulate (TSP) sample was collected hourly in Xi'an, an inland megacity of China near the Loess Plateau, during a dust storm event of 2013 (9 March 18:00-12 March 10:00 LT), along with a size-resolved aerosol sampling and an online measurement of PM2.5. The TSP and size-resolved samples were determined for elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC) and nitrogen (WSON), inorganic ions and elements to investigate chemistry evolution of dust particles. Hourly concentrations of Cl-, NO3-, SO42-, Na+ and Ca2+ in the TSP samples reached up to 34, 12, 180, 72 and 28 μg m-3, respectively, when dust peak arrived over Xi'an. Chemical compositions of the TSP samples showed that during the whole observation period NH4+ and NO3- were linearly correlated with each other (r2=0.76) with a molar ratio of 1 : 1, while SO42- and Cl- were well correlated with Na+, Ca2+, Mg2+ and K+ (r2 > 0.85). Size distributions of NH4+ and NO3- presented a same pattern, which dominated in the coarse mode (> 2.1 μm) during the event and predominated in the fine mode (hours, but both exhibited two equivalent peaks in both the fine and the coarse modes during the non-event, due to the fine-mode accumulations of secondarily produced SO42- and biomass-burning-emitted Cl- and the coarse-mode enrichments of urban soil-derived SO42- and Cl-. Linear fit regression analysis further indicated that SO42- and Cl- in the dust samples possibly exist as Na2SO4, CaSO4 and NaCl, which directly originated from Gobi desert surface soil, while NH4+ and NO3- in the dust samples exist as NH4NO3. We propose a mechanism to explain these observations in which aqueous phase of dust particle surface is formed via uptake of water vapor by hygroscopic salts such as Na2SO4 and NaCl, followed by heterogeneous formation of nitrate on the liquid phase and subsequent absorption of ammonia. Our data indicate that 54 ± 20% and 60 ± 23% of NH4+ and NO3- during the dust period

  2. Book Reviews in Periodicals.

    Science.gov (United States)

    Ettelt, Harold J.

    All recent issues of periodicals found which contain indexed book reviews are listed in this compilation from Drake Memorial Library at the New York State University at Brockport. The periodicals are listed by 29 subject headings in this informal guide designed to be used at Drake Library. The number of reviews in the periodical in a recent year…

  3. Painful menstrual periods

    Science.gov (United States)

    Menstruation - painful; Dysmenorrhea; Periods - painful; Cramps - menstrual; Menstrual cramps ... into two groups, depending on the cause: Primary dysmenorrhea Secondary dysmenorrhea Primary dysmenorrhea is menstrual pain that ...

  4. Middle Helladic Period

    DEFF Research Database (Denmark)

    Sarri, Kalliopi

    1999-01-01

    and their quality was improved considerably toward the end of this period. The profound cultural innovations of the Middle Helladic period were initially interpreted as a result of violent population movement and troubles provoked by the coming of the first Indo-European races. However, this matter does no more...... Helladic period is considered as a period of economic and social decline it was the time during which the mainland features merged with the insular influence, that is all the Aegean elements which led to the creation of the Mycenaean civilization were mixed in a creative way....

  5. On some periodicity effects

    DEFF Research Database (Denmark)

    Sorokin, Sergey V.

    2015-01-01

    The talk is concerned with the modelling of wave propagation in and vibration of periodic elastic structures. Although analysis of wave-guide properties of infinite periodic structures is a well establish research subject, some issues have not yet been fully addressed in the literature. The aim o...

  6. The Living Periodic Table

    Science.gov (United States)

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  7. Periods and Nori motives

    CERN Document Server

    Huber, Annette

    2017-01-01

    This book casts the theory of periods of algebraic varieties in the natural setting of Madhav Nori’s abelian category of mixed motives. It develops Nori’s approach to mixed motives from scratch, thereby filling an important gap in the literature, and then explains the connection of mixed motives to periods, including a detailed account of the theory of period numbers in the sense of Kontsevich-Zagier and their structural properties. Period numbers are central to number theory and algebraic geometry, and also play an important role in other fields such as mathematical physics. There are long-standing conjectures about their transcendence properties, best understood in the language of cohomology of algebraic varieties or, more generally, motives. Readers of this book will discover that Nori’s unconditional construction of an abelian category of motives (over fields embeddable into the complex numbers) is particularly well suited for this purpose. Notably, Kontsevich's formal period algebra represents a to...

  8. A Research of Construction Mechanism of Vassal State's City Group during Spring and Autumn Period Based on the Analyzation of Geographic Image - Take south region of Shandong as example

    Science.gov (United States)

    Gao, X.; Li, B.; Zhou, X.

    2015-08-01

    Spring and Autumn period, the vassal states began to carry out country defense construction actively, brought changes to building the ideological. At that time, the south region of Shandong, as an independent unit of geography, seldom affected by external factors, and had striking cultural characteristics. Vassal states there constructed their capital mainly to defense the neighboring countries and cope with small scale mergers war, not involving the nationwide military deployment. Therefore, the region reflect the construction thought changes during the Spring and Autumn Period, and consistent with the research purpose. Based on this judgment, the author analyzed each capital's location and terrain feature by topographic map. In brief, the Spring and Autumn Period, feudal states acted of one's own free will, the relationship between cities contained the one within and between vassal states. Within vassal state relationships included economic support, entrenching each other and protecting the country together. Meanwhile, strategic defensing, scrambling for resources and geographical location comprised of the competition between vassal states. In the agrarian age, the political centers and agricultural areas were interdependent, giving priority to the development of political cities. Transformation of capitals' space layout was actually the process of carving up farming plains, the powerful states occupy favorable geographical position, and the small countries would be encroached and annexed gradually.

  9. Mean-periodic functions

    Directory of Open Access Journals (Sweden)

    Carlos A. Berenstein

    1980-01-01

    Full Text Available We show that any mean-periodic function f can be represented in terms of exponential-polynomial solutions of the same convolution equation f satisfies, i.e., u∗f=0(μ∈E′(ℝn. This extends to n-variables the work of L. Schwartz on mean-periodicity and also extends L. Ehrenpreis' work on partial differential equations with constant coefficients to arbitrary convolutors. We also answer a number of open questions about mean-periodic functions of one variable. The basic ingredient is our work on interpolation by entire functions in one and several complex variables.

  10. Painful periods (dysmenorrhea) (image)

    Science.gov (United States)

    Primary dysmenorrhea is a normal cramping of the lower abdomen caused by hormone-induced uterine contractions before the period. Secondary dysmenorrhea may be caused by abnormal conditions such as ...

  11. Vaginal bleeding between periods

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003156.htm Vaginal bleeding between periods To use the sharing features ... this page, please enable JavaScript. This article discusses vaginal bleeding that occurs between a woman's monthly menstrual ...

  12. Super periodic potential

    Science.gov (United States)

    Hasan, Mohammd; Mandal, Bhabani Prasad

    2018-04-01

    In this paper we introduce the concept of super periodic potential (SPP) of arbitrary order n, n ∈I+, in one dimension. General theory of wave propagation through SPP of order n is presented and the reflection and transmission coefficients are derived in their closed analytical form by transfer matrix formulation. We present scattering features of super periodic rectangular potential and super periodic delta potential as special cases of SPP. It is found that the symmetric self-similarity is the special case of super periodicity. Thus by identifying a symmetric fractal potential as special cases of SPP, one can obtain the tunnelling amplitude for a particle from such fractal potential. By using the formalism of SPP we obtain the close form expression of tunnelling amplitude of a particle for general Cantor and Smith-Volterra-Cantor potentials.

  13. Establishing contract periods

    International Nuclear Information System (INIS)

    Huffman, F.C.

    1978-01-01

    The lead time for executing the Adjustable Fixed-Commitment (AFC) contract and exceptions which may be considered are discussed. The initial delivery period is also discussed. Delays, deferrals, and schedule adjustment charges are finally considered

  14. The Periodic Table CD.

    Science.gov (United States)

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  15. Setting the Periodic Table.

    Science.gov (United States)

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  16. Supersymmetrically transformed periodic potentials

    OpenAIRE

    C, David J. Fernandez

    2003-01-01

    The higher order supersymmetric partners of a stationary periodic potential are studied. The transformation functions associated to the band edges do not change the spectral structure. However, when the transformation is implemented for factorization energies inside of the forbidden bands, the final potential will have again the initial band structure but it can have bound states encrusted into the gaps, giving place to localized periodicity defects.

  17. Thyrotoxic periodic paralysis

    OpenAIRE

    Rojith Karandode Balakrishnan; Suresh Rama Chandran; Geetha Thirumalnesan; Nedumaran Doraisamy

    2011-01-01

    This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recove...

  18. Evolutionary dynamics of incubation periods.

    Science.gov (United States)

    Ottino-Loffler, Bertrand; Scott, Jacob G; Strogatz, Steven H

    2017-12-21

    The incubation period for typhoid, polio, measles, leukemia and many other diseases follows a right-skewed, approximately lognormal distribution. Although this pattern was discovered more than sixty years ago, it remains an open question to explain its ubiquity. Here, we propose an explanation based on evolutionary dynamics on graphs. For simple models of a mutant or pathogen invading a network-structured population of healthy cells, we show that skewed distributions of incubation periods emerge for a wide range of assumptions about invader fitness, competition dynamics, and network structure. The skewness stems from stochastic mechanisms associated with two classic problems in probability theory: the coupon collector and the random walk. Unlike previous explanations that rely crucially on heterogeneity, our results hold even for homogeneous populations. Thus, we predict that two equally healthy individuals subjected to equal doses of equally pathogenic agents may, by chance alone, show remarkably different time courses of disease.

  19. Periodic review in natural resource contracts | Mandelbaum ...

    African Journals Online (AJOL)

    Periodic contract review mechanisms, which are provisions in contracts that formally require parties to meet at particular intervals to review the terms of the contract, are mechanisms that may facilitate the process of negotiating contractual changes to accommodate changing circumstances over the term of extractive ...

  20. Long-Period Solar Variability

    Energy Technology Data Exchange (ETDEWEB)

    GAUTHIER,JOHN H.

    2000-07-20

    Terrestrial climate records and historical observations of the Sun suggest that the Sun undergoes aperiodic oscillations in radiative output and size over time periods of centuries and millenia. Such behavior can be explained by the solar convective zone acting as a nonlinear oscillator, forced at the sunspot-cycle frequency by variations in heliomagnetic field strength. A forced variant of the Lorenz equations can generate a time series with the same characteristics as the solar and climate records. The timescales and magnitudes of oscillations that could be caused by this mechanism are consistent with what is known about the Sun and terrestrial climate.

  1. Periodic table of elements

    International Nuclear Information System (INIS)

    Fluck, E.; Heumann, K.G.

    1985-01-01

    Following a recommendation by the International Union for Pure and Applied Chemistry (IUPAC), the groups of the periodic table shall be numbered from 1 to 18, instead of I to VIII as before. The recommendations has been approved of by the Committee on Nomenclature of the American Chemical Society. The new system abandons the distinction between main groups (a) and auxiliary groups (b), which in the past frequently has been the reason for misunderstandings between European and American chemists, due to different handling. The publishing house VCH Verlagsgesellschaft recently produced a new periodic table that shows the old and the new numbering system together at a glance, so that chemists will have time to get familiar with the new system. In addition the new periodic table represents an extensive data compilation arranged by elements. The front page lists the chemical properties of elements, the back page their physical properties. (orig./EF) [de

  2. Thyrotoxic periodic paralysis

    Directory of Open Access Journals (Sweden)

    Rojith Karandode Balakrishnan

    2011-01-01

    Full Text Available This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recovery after the medical intervention and was discharged after 24 hours with no residual paralysis. Thyrotoxic periodic paralysis (TPP is a complication of thyrotoxicosis, more common amongst males in Asia. It presents as acute flaccid paralysis in a case of hyperthyroidism with associated hypokalemia. The features of thyrotoxicosis may be subtle or absent. Thus, in cases of recurrent or acute flaccid muscle paralysis, it is important to consider thyrotoxicosis as one of the possible causes, and take measures accordingly.

  3. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  4. Hereditary periodic fever syndromes

    NARCIS (Netherlands)

    McDermott, MF; Frenkel, J

    Hereditary periodic fever syndromes are defined by recurrent attacks of generalised inflammation for which no infectious or auto-immune cause can be identified. For most of these disorders, the molecular basis has recently been elucidated. This has opened the prospect of novel therapeutic

  5. Almost periodic Schroedinger operators

    International Nuclear Information System (INIS)

    Bellissard, J.; Lima, R.

    1984-01-01

    These lectures are devoted to recent developments in the theory of almost-periodic Schroedinger Operators. We specially describe the algebraic point of view, with applications to gap-labelling theorems. Particular models are also presented which exhibit various spectral properties. (orig.)

  6. Astrophysical implications of periodicity

    International Nuclear Information System (INIS)

    Muller, R.A.

    1988-01-01

    Two remarkable discoveries of the last decade have profound implications for astrophysics and for geophysics. These are the discovery by Alvarez et al., that certain mass extinctions are caused by the impact on the earth of a large asteroid or comet, and the discovery by Raup and Sepkoski that such extinctions are periodic, with a cycle time of 26 to 30 million years. The validity of both of these discoveries is assumed and the implications are examined. Most of the phenomena described depend not on periodicity, but just on the weaker assumption that the impacts on the earth take place primarily in showers. Proposed explanations for the periodicity include galactic oscillations, the Planet X model, and the possibility of Nemesis, a solar companion star. These hypotheses are critically examined. Results of the search for the solar companion are reported. The Deccan flood basalts of India have been proposed as the impact site for the Cretaceous impact, but this hypotheisis is in contradiction with the conclusion of Courtillot et al., that the magma flow began during a period of normal magnetic field. A possible resolution of this contradiction is proposed

  7. Periodic Table of Students.

    Science.gov (United States)

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  8. A Modern Periodic Table.

    Science.gov (United States)

    Herrenden-Harker, B. D.

    1997-01-01

    Presents a modern Periodic Table based on the electron distribution in the outermost shell and the order of filling of the sublevels within the shells. Enables a student to read off directly the electronic configuration of the element and the order in which filling occurs. (JRH)

  9. Directional wave and temperature data from thirteen buoys at San Nicolas Island, Dana Point and Oceanside, CA, 1997-2002 (NODC Accession 0000774)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Data Information Program (CDIP) is an extensive network for monitoring waves along the coastlines of the United States, with a strong emphasis on our...

  10. Long term behaviour of low and intermediate level waste packages under repository conditions. Results of a co-ordinated research project 1997-2002

    International Nuclear Information System (INIS)

    2004-06-01

    The development and application of approaches and technologies that provide long term safety is an essential issue in the disposal of radioactive waste. For low and intermediate level radioactive waste, engineered barriers play an important role in the overall safety and performance of near surface repositories. Thus, developing a strong technical basis for understanding the behaviour and performance of engineered barriers is an important consideration in the development and establishment of near surface repositories for radioactive waste. In 1993, a Co-ordinated Research Project (CRP) on Performance of Engineered Barrier Materials in Near Surface Disposal Facilities for Radioactive Waste was initiated by the IAEA with the twin goals of addressing some of the gaps in the database on radionuclide isolation and long term performance of a wide variety of materials and components that constitute the engineered barriers system (IAEA-TECDOC-1255 (2001)). However, during the course of the CRP, it was realized that that the scope of the CRP did not include studies of the behaviour of waste packages over time. Given that a waste package represents an important component of the overall near surface disposal system and the fact that many Member States have active R and D programmes related to waste package testing and evaluation, a new CRP was launched, in 1997, on Long Term Behaviour of Low and Intermediate Level Waste Packages Under Repository Conditions. The CRP was intended to promote research activities on the subject area in Member States, share information on the topic among the participating countries, and contribute to advancing technologies for near surface disposal of radioactive waste. Thus, this CRP complements the afore mentioned CRP on studies of engineered barriers. With the active participation and valuable contributions from twenty scientists and engineers from Argentina, Canada, Czech Republic, Egypt, Finland, India, Republic of Korea, Norway, Romania, Russian Federation, Spain, Thailand, United Kingdom, and the United States of America, this report provides an overview of scientific and technical issues related to the behaviour and performance of a wide range of low and intermediate level waste packages in the context of overall repository performance and safety. Specific approaches for the testing and assessment of waste package components, including modelling considerations in predicting waste package performance, are presented and discussed. In addition, the major findings of the research projects, carried out within the framework of the CRP, are presented, summarizing the variety of approaches and technologies used in waste package development, testing and evaluation

  11. Aspectos epidemiológicos do dengue no Município de São Luís, Maranhão, Brasil, 1997-2002

    Directory of Open Access Journals (Sweden)

    Gonçalves Neto Vicente Silva

    2004-01-01

    Full Text Available Foram notificados 12.008 casos de dengue no período de 1997 a 2002, com picos em 1997 (35,80% e 1998 (45,80%. A doença predominou na faixa etária de 15-49 anos (72,20% e na estação chuvosa (83,30%, correlacionando-se positivamente com a precipitação pluviométrica (r = 0,84 e a umidade relativa (r = 0,76, e negativamente com a temperatura (r = -0,78. Não houve diferença significativa (chi2 = 2,319; p > 0,05 no número de casos entre os sexos masculino (49,00% e feminino (51,00%. Os sete distritos sanitários resultaram positivos: Tirirical (27,00%, Coroadinho (17,00%, Bequimão (16,00%, Cohab (14,00%, Itaqui-Bacanga (11,00%, Centro (8,00% e Vila Esperança (7,00%. O índice de infestação predial oscilou de 1,01 a 7,15 e o índice de Breteau, de 1,10 a 8,18. Os depósitos mais freqüentes foram: tambor e similares (80,00%, vaso de planta (4,70%, garrafa, lata e plástico (3,60%, pneu (3,30% e caixa d'água (2,70%; os demais representaram 5,7%. Para Ae. aegyptiforam encontrados 134.631 depósitos positivos, predominando os do tipo B (80,00%, seguidos pelos dos tipos C (4,70%, E (3,60% e A (3,30%.

  12. Aspectos epidemiológicos do dengue no Município de São Luís, Maranhão, Brasil, 1997-2002

    Directory of Open Access Journals (Sweden)

    Vicente Silva Gonçalves Neto

    Full Text Available Foram notificados 12.008 casos de dengue no período de 1997 a 2002, com picos em 1997 (35,80% e 1998 (45,80%. A doença predominou na faixa etária de 15-49 anos (72,20% e na estação chuvosa (83,30%, correlacionando-se positivamente com a precipitação pluviométrica (r = 0,84 e a umidade relativa (r = 0,76, e negativamente com a temperatura (r = -0,78. Não houve diferença significativa (chi2 = 2,319; p > 0,05 no número de casos entre os sexos masculino (49,00% e feminino (51,00%. Os sete distritos sanitários resultaram positivos: Tirirical (27,00%, Coroadinho (17,00%, Bequimão (16,00%, Cohab (14,00%, Itaqui-Bacanga (11,00%, Centro (8,00% e Vila Esperança (7,00%. O índice de infestação predial oscilou de 1,01 a 7,15 e o índice de Breteau, de 1,10 a 8,18. Os depósitos mais freqüentes foram: tambor e similares (80,00%, vaso de planta (4,70%, garrafa, lata e plástico (3,60%, pneu (3,30% e caixa d'água (2,70%; os demais representaram 5,7%. Para Ae. aegyptiforam encontrados 134.631 depósitos positivos, predominando os do tipo B (80,00%, seguidos pelos dos tipos C (4,70%, E (3,60% e A (3,30%.

  13. Thyrotoxic periodic paralysis

    International Nuclear Information System (INIS)

    Ferreiro, J.E.; Arguelles, D.J.; Rams, H. Jr.

    1986-01-01

    A case of thyrotoxic periodic paralysis is reported in a Hispanic man with an unusual recurrence six weeks after radioactive iodine treatment. Thyrotoxic periodic paralysis has now been well characterized in the literature: it occurs primarily in Orientals with an overwhelming male preponderance and a higher association of specific HLA antigens. Clinical manifestations include onset after high carbohydrate ingestion or heavy exertion, with progressive symmetric weakness leading to flaccid paralysis of the extremities and other muscle groups, lasting several hours. If hypokalemia is present, potassium administration may help abort the attack. Although propranolol can be efficacious in preventing further episodes, the only definitive treatment is establishing a euthyroid state. The pathophysiology is still controversial, but reflects altered potassium and calcium dynamics as well as certain morphologic characteristics within the muscle unit itself

  14. Deciphering Periodic Methanol Masers

    Science.gov (United States)

    Stecklum, Bringfried; Caratti o Garatti, Alessio; Henning, Thomas; Hodapp, Klaus; Hopp, Ulrich; Kraus, Alex; Linz, Hendrik; Sanna, Alberto; Sobolev, Andrej; Wolf, Verena

    2018-05-01

    Impressive progress has been made in recent years on massive star formation, yet the involved high optical depths even at submm/mm wavelengths make it difficult to reveal its details. Recently, accretion bursts of massive YSOs have been identified to cause flares of Class II methanol masers (methanol masers for short) due to enhanced mid-IR pumping. This opens a new window to protostellar accretion variability, and implies that periodic methanol masers hint at cyclic accretion. Pinning down the cause of the periodicity requires joint IR and radio monitoring. We derived the first IR light curve of a periodic maser host from NEOWISE data. The source, G107.298+5.639, is an intermediate-mass YSO hosting methanol and water masers which flare every 34.5 days. Our recent joint K-band and radio observations yielded first but marginal evidence for a phase lag between the rise of IR and maser emission, respectively, and revealed that both NEOWISE and K-band light curves are strongly affected by the light echo from the ambient dust. Both the superior resolution of IRAC over NEOWISE and the longer wavelengths compared to our ground-based imaging are required to inhibit the distractive contamination by the light echo. Thus, we ask for IRAC monitoring of G107 to cover one flare cycle, in tandem with 100-m Effelsberg and 2-m Wendelstein radio and NIR observations to obtain the first high-quality synoptic measurements of this kind of sources. The IR-maser phase lag, the intrinsic shape of the IR light curves and their possible color variation during the cycle allow us to constrain models for the periodic maser excitation. Since methanol masers are signposts of intermediate-mass and massive YSOs, deciphering their variability offers a clue to the dynamics of the accretion-mediated growth of massive stars and their feedback onto the immediate natal environment. The Spitzer light curve of such a maser-hosting YSO would be a legacy science product of the mission.

  15. Periodic folding of viscous sheets

    Science.gov (United States)

    Ribe, Neil M.

    2003-09-01

    The periodic folding of a sheet of viscous fluid falling upon a rigid surface is a common fluid mechanical instability that occurs in contexts ranging from food processing to geophysics. Asymptotic thin-layer equations for the combined stretching-bending deformation of a two-dimensional sheet are solved numerically to determine the folding frequency as a function of the sheet’s initial thickness, the pouring speed, the height of fall, and the fluid properties. As the buoyancy increases, the system bifurcates from “forced” folding driven kinematically by fluid extrusion to “free” folding in which viscous resistance to bending is balanced by buoyancy. The systematics of the numerically predicted folding frequency are in good agreement with laboratory experiments.

  16. Supersymmetric mechanics

    International Nuclear Information System (INIS)

    Stelle, Kellogg S

    2007-01-01

    With the development of the electronic archives in high-energy physics, there has been increasing questioning of the role of traditional publishing styles, particularly in the production of conference books. One aspect of traditional publishing that still receives wide appreciation, however, is in the production of well-focussed pedagogical material. The present two-volume edition, 'Supersymmetric Mechanics-Vol 1', edited by S Bellucci and 'Supersymmetric Mechanics-Vol 2', edited by S Bellucci, S Ferrara and A Marrani, is a good example of the kind of well-digested presentation that should still find its way into university libraries. This two-volume set presents the material of a set of pedagogical lectures presented at the INFN National Laboratory in Frascati over a two-year period on the subject of supersymmetric mechanics. The articles include the results of discussions with the attending students after the lectures. Overall, this makes for a useful compilation of material on a subject that underlies much of the current effort in supersymmetric approaches to cosmology and the unification programme. The first volume comprises articles on 'A journey through garden algebras' by S Bellucci, S J Gates Jr and E Orazi on linear supermultiplet realizations in supersymmetric mechanics,'Supersymmetric mechanics in superspace' by S Bellucci and S Krivonos, 'Noncommutative mechanics, Landau levels, twistors and Yang-Mills amplitudes' by V P Nair, 'Elements of (super) Hamiltonian formalism' by A Nersessian and 'Matrix mechanics' by C Sochichiu. The second volume consists entirely of a masterful presentation on 'The attractor mechanism and space time singularities' by S Ferrara. This presents a comprehensive and detailed overview of the structure of supersymmetric black hole solutions in supergravity, critical point structure in the scalar field moduli space and the thermodynamic consequences. This second volume alone makes the set a worthwhile addition to the research

  17. Periodically modulated dark states

    Science.gov (United States)

    Han, Yingying; Zhang, Jun; Zhang, Wenxian

    2018-04-01

    Phenomena of electromagnetically induced transparency (PEIT) may be interpreted by the Autler-Townes Splitting (ATS), where the coupled states are split by the coupling laser field, or by the quantum destructive interference (QDI), where the atomic phases caused by the coupling laser and the probe laser field cancel. We propose modulated experiments to explore the PEIT in an alternative way by periodically modulating the coupling and the probe fields in a Λ-type three-level system initially in a dark state. Our analytical and numerical results rule out the ATS interpretation and show that the QDI interpretation is more appropriate for the modulated experiments. Interestingly, dark state persists in the double-modulation situation where control and probe fields never occur simultaneously, which is significant difference from the traditional dark state condition. The proposed experiments are readily implemented in atomic gases, artificial atoms in superconducting quantum devices, or three-level meta-atoms in meta-materials.

  18. [Childhood periodic syndromes].

    Science.gov (United States)

    Cuvellier, J-C; Lépine, A

    2010-01-01

    This review focuses on the so-called "periodic syndromes of childhood that are precursors to migraine", as included in the Second Edition of the International Classification of Headache Disorders. Three periodic syndromes of childhood are included in the Second Edition of the International Classification of Headache Disorders: abdominal migraine, cyclic vomiting syndrome and benign paroxysmal vertigo, and a fourth, benign paroxysmal torticollis is presented in the Appendix. The key clinical features of this group of disorders are the episodic pattern and intervals of complete health. Episodes of benign paroxysmal torticollis begin between 2 and 8 months of age. Attacks are characterized by an abnormal inclination and/or rotation of the head to one side, due to cervical dystonia. They usually resolve by 5 years. Benign paroxysmal vertigo presents as sudden attacks of vertigo, accompanied by inability to stand without support, and lasting seconds to minutes. Age at onset is between 2 and 4 years, and the symptoms disappear by the age of 5. Cyclic vomiting syndrome is characterized in young infants and children by repeated stereotyped episodes of pernicious vomiting, at times to the point of dehydration, and impacting quality of life. Mean age of onset is 5 years. Abdominal migraine remains a controversial issue and presents in childhood with repeated stereotyped episodes of unexplained abdominal pain, nausea and vomiting occurring in the absence of headache. Mean age of onset is 7 years. Both cyclic vomiting syndrome and abdominal migraine are noted for the absence of pathognomonic clinical features but also for the large number of other conditions to be considered in their differential diagnoses. Diagnostic criteria, such as those of the Second Edition of the International Classification of Headache Disorders and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition, have made diagnostic approach and management easier. Their diagnosis

  19. Nonparametric Inference for Periodic Sequences

    KAUST Repository

    Sun, Ying; Hart, Jeffrey D.; Genton, Marc G.

    2012-01-01

    the periodogram, a widely used tool for period estimation. The CV method is computationally simple and implicitly penalizes multiples of the smallest period, leading to a "virtually" consistent estimator of integer periods. This estimator is investigated both

  20. Magnetomechanically induced long period fiber gratings

    International Nuclear Information System (INIS)

    Causado-Buelvas, Jesus D.; Gomez-Cardona, Nelson D.; Torres, Pedro

    2008-01-01

    In this work, we report a simple, flexible method to create long period fiber gratings mechanically by controlling the repulsion/attraction force between two magnets that pressing a plate with a periodic array of small glass cylinders to a short length of optical fiber. Via the photoelastic effect, the pressure points induce the required periodic refractive index modulation to create the LPFG. We found that the induced device exhibits spectral characteristics similar to those of other types of LPFG. As the optical properties of LPFGs are directly related to the nature of the applied perturbations, we show, to our knowledge for the frrst time, how is the evolution of birefringence effects in mechanically induced LPFGs

  1. Electromagnetic Radiation of Electrons in Periodic Structures

    CERN Document Server

    Potylitsyn, Alexander Petrovich

    2011-01-01

    Periodic magnetic structures (undulators) are widely used in accelerators to generate monochromatic undulator radiation (UR) in the range from far infrared to the hard X-ray region. Another periodic crystalline structure is used to produce quasimonochromatic polarized photon beams via the coherent bremsstrahlung mechanism (CBS). Due to such characteristics as monochromaticity, polarization and adjustability, these types of radiation is of large interest for applied and basic research of accelerator-emitted radiation. The book provides a detailed overview of the fundamental principles behind electromagnetic radiation emitted from accelerated charged particles (e.g. UR, CBS, radiation of fast electrons in Laser flash fields) as well as a unified description of relatively new radiation mechanisms which attracted great interest in recent years. This are the so-called polarization radiation excited by the Coulomb field of incident particles in periodic structures, parametric X-rays, resonant transition radiation a...

  2. Quantum mechanics of rapidly and periodically driven systems

    Indian Academy of Sciences (India)

    ansatz, through the formulation of the Schrödinger equation. The result, like .... The underlying strategy is to make an asymptotic expansion of the generator S ..... MB acknowledges financial support from the Council of Scientific and Industrial.

  3. Periodization Theory: Confronting an Inconvenient Truth.

    Science.gov (United States)

    Kiely, John

    2018-04-01

    Periodization theory has, over the past seven decades, emerged as the preeminent training planning paradigm. The philosophical underpinnings of periodization theory can be traced back to the integration of diverse shaping influences, whereby coaching beliefs and traditions were blended with historically available scientific insights and contextualized against pervading social planning models. Since then, many dimensions of elite preparation have evolved significantly, as driven by a combination of coaching innovations and science-led advances in training theory, techniques, and technologies. These advances have been incorporated into the fabric of the pre-existing periodization planning framework, yet the philosophical assumptions underpinning periodization remain largely unchallenged and unchanged. One particularly influential academic sphere of study, the science of stress, particularly the work of Hans Selye, is repeatedly cited by theorists as a central pillar upon which periodization theory is founded. A fundamental assumption emanating from the early stress research is that physical stress is primarily a biologically mediated phenomenon: a presumption translated to athletic performance contexts as evidence that mechanical training stress directly regulates the magnitude of subsequent 'fitness' adaptations. Interestingly, however, since periodization theory first emerged, the science of stress has evolved extensively from its historical roots. This raises a fundamental question: if the original scientific platform upon which periodization theory was founded has disintegrated, should we critically re-evaluate conventional perspectives through an updated conceptual lens? Realigning periodization philosophy with contemporary stress theory thus presents us with an opportunity to recalibrate training planning models with both contemporary scientific insight and progressive coaching practice.

  4. Testing periodically integrated autoregressive models

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); M.J. McAleer (Michael)

    1997-01-01

    textabstractPeriodically integrated time series require a periodic differencing filter to remove the stochastic trend. A non-periodic integrated time series needs the first-difference filter for similar reasons. When the changing seasonal fluctuations for the non-periodic integrated series can be

  5. Concurrent hypokalemic periodic paralysis and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Chia-Lin Lin

    2015-01-01

    Full Text Available Primary periodic paralysis is a rare autosomal dominant disorder of ion-channel dysfunction, manifested by episodic flaccid paresis secondary to abnormal sarcolemma excitability. Membrane destabilization involving Na, K-ATPase has been hypothesized to be a biological etiology of the bipolar disorder (BD and the mechanisms underlying lithium therapy have been linked to it. To date, there has been only one reported case of BD comorbid with periodic paralysis. Herein, we reported another case of concurrent bipolar mania and hypokalemic periodic paralysis (HPP, one special form of periodic paralysis. Consistent with the previous case, our patient responded well to lithium treatment for both bipolar mania and HPP. This might provide some support to the hypothesis that the therapeutic effects of lithium in both BD and HPP could be due to the correction of the underlying common pathophysiology.

  6. Global bioevents and the question of periodicity

    Science.gov (United States)

    Sepkoski, J. John

    The hypothesis of periodicity in extinction is an empirical claim that extinction events, while variable in magnitude, are regular in timing and therefore are serially dependent upon some single, ultimate cause with clocklike behavior. This hypothesis is controversal, in part because of questions regarding the identity and timing of certain extinction events and because of speculations concerning possible catastrophic extraterrestrial forcing mechanisms. New data on extinctions of marine animal genera are presented that display a high degree of periodicity in the Mesozoic and Cenozoic as well as a suggestion of nonstationary periodicity in the late Paleozoic. However, no periodicity is evident among the as yet poorly documented extinction events of the early and middle Paleozoic.

  7. Broiler adaptation to post-hatching period

    Directory of Open Access Journals (Sweden)

    Maiorka Alex

    2006-01-01

    Full Text Available In the latest years more attention has been given to mechanisms for bird adaptation at post-hatching period by management of environmental conditions and formulations of diets offered during this period when digestive, immune, and thermo-regulating systems suffer slight changes. In post-hatching period, digestive system is anatomically complete, but its functionality is still immature in relation to adult birds. The chick immunity depends on maternal antibodies transferred to egg just before laying. In addition, variations within thermal comfort zone might affect initial development of chick. For example, high temperatures may induce hyperthermia with dehydration, while low temperatures may lead to hypothermia responsible by pulmonary hypertension syndrome. In conclusion, productivity might be enhanced when good conditions are offered to chicks during the period from last embryo development to first days after hatching.

  8. Diagnóstico tardío de la infección por el virus de la inmunodeficiencia humana en la Cohorte VACH (1997-2002 Delayed diagnosis of HIV infection in the Spanish VACH cohort (1997-2002

    Directory of Open Access Journals (Sweden)

    Ramón Teira Cobo

    2007-02-01

    Full Text Available Objetivo: Estudiar la prevalencia del diagnóstico tardío (DT de la infección por el virus de la inmunodeficiencia humana (VIH y sus factores asociados. Métodos: Estudio transversal sobre los pacientes incluidos en la cohorte VACH cuya infección por el VIH hubiese sido diagnosticada entre 1997 y 2002. Consideramos DT los casos diagnosticados de sida concomitantemente o dentro del primer mes desde la primera serología positiva, o con recuento de CD4+ Objective: To study the prevalence of delayed diagnosis of HIV infection and associated factors. Methods: A cross sectional study of patients included in the Spanish VACH cohort who had been diagnosed with HIV infection between 1997 and 2002 was performed. Delayed diagnosis was defined as patients diagnosed with HIV infection and AIDS simultaneously or within the first month after the first positive serologic test, or those with a first CD4+ cell count below 200/ml. The epidemiological characteristics of these patients were compared with those of the remaining patients. Results: Of 2,820 new cases of HIV infection, delayed diagnosis was found in 506 (18%. These patients differed from the remaining patients in their lower mean age and higher HIV viral load, as well as in their distribution by sex (higher proportion of males, occupational status, history of incarceration in prison, and HIV-risk transmission group. The median survival during follow-up was significantly lower among AIDS patients with a delayed diagnosis. Conclusions: Delayed diagnosis remains a cause for concern in our environment, due to its magnitude and its association with mortality. Some epidemiological characteristics provide clues to guide future programs directed at increasing information and improving prevention.

  9. Periodic feedback stabilization for linear periodic evolution equations

    CERN Document Server

    Wang, Gengsheng

    2016-01-01

    This book introduces a number of recent advances regarding periodic feedback stabilization for linear and time periodic evolution equations. First, it presents selected connections between linear quadratic optimal control theory and feedback stabilization theory for linear periodic evolution equations. Secondly, it identifies several criteria for the periodic feedback stabilization from the perspective of geometry, algebra and analyses respectively. Next, it describes several ways to design periodic feedback laws. Lastly, the book introduces readers to key methods for designing the control machines. Given its coverage and scope, it offers a helpful guide for graduate students and researchers in the areas of control theory and applied mathematics.

  10. The redoubtable ecological periodic table

    Science.gov (United States)

    Ecological periodic tables are repositories of reliable information on quantitative, predictably recurring (periodic) habitat–community patterns and their uncertainty, scaling and transferability. Their reliability derives from their grounding in sound ecological principle...

  11. Periodic waves in nonlinear metamaterials

    International Nuclear Information System (INIS)

    Liu, Wen-Jun; Xiao, Jing-Hua; Yan, Jie-Yun; Tian, Bo

    2012-01-01

    Periodic waves are presented in this Letter. With symbolic computation, equations for monochromatic waves are studied, and analytic periodic waves are obtained. Factors affecting properties of periodic waves are analyzed. Nonlinear metamaterials, with the continuous distribution of the dielectric permittivity obtained, are different from the ones with the discrete distribution. -- Highlights: ► Equations for the monochromatic waves in transverse magnetic polarization have been studied. ► Analytic periodic waves for the equations have been obtained. ► Periodic waves are theoretically presented and studied in the nonlinear metamaterials.

  12. Theoretical chemistry periodicities in chemistry and biology

    CERN Document Server

    Eyring, Henry

    1978-01-01

    Theoretical Chemistry: Periodicities in Chemistry and Biology, Volume 4 covers the aspects of theoretical chemistry. The book discusses the stably rotating patterns of reaction and diffusion; the chemistry of inorganic systems exhibiting nonmonotonic behavior; and population cycles. The text also describes the mathematical modeling of excitable media in neurobiology and chemistry; oscillating enzyme reactions; and oscillatory properties and excitability of the heart cell membrane. Selected topics from the theory of physico-chemical instabilities are also encompassed. Chemists, mechanical engin

  13. Nonparametric Inference for Periodic Sequences

    KAUST Repository

    Sun, Ying

    2012-02-01

    This article proposes a nonparametric method for estimating the period and values of a periodic sequence when the data are evenly spaced in time. The period is estimated by a "leave-out-one-cycle" version of cross-validation (CV) and complements the periodogram, a widely used tool for period estimation. The CV method is computationally simple and implicitly penalizes multiples of the smallest period, leading to a "virtually" consistent estimator of integer periods. This estimator is investigated both theoretically and by simulation.We also propose a nonparametric test of the null hypothesis that the data have constantmean against the alternative that the sequence of means is periodic. Finally, our methodology is demonstrated on three well-known time series: the sunspots and lynx trapping data, and the El Niño series of sea surface temperatures. © 2012 American Statistical Association and the American Society for Quality.

  14. Positive periodic solutions of delayed periodic Lotka-Volterra systems

    International Nuclear Information System (INIS)

    Lin Wei; Chen Tianping

    2005-01-01

    In this Letter, for a general class of delayed periodic Lotka-Volterra systems, we prove some new results on the existence of positive periodic solutions by Schauder's fixed point theorem. The global asymptotical stability of positive periodic solutions is discussed further, and conditions for exponential convergence are given. The conditions we obtained are weaker than the previously known ones and can be easily reduced to several special cases

  15. Mechanics without mechanisms

    Science.gov (United States)

    Eisenthal, Joshua

    2018-05-01

    At the time of Heinrich Hertz's premature death in 1894, he was regarded as one of the leading scientists of his generation. However, the posthumous publication of his treatise in the foundations of physics, Principles of Mechanics, presents a curious historical situation. Although Hertz's book was widely praised and admired, it was also met with a general sense of dissatisfaction. Almost all of Hertz's contemporaries criticized Principles for the lack of any plausible way to construct a mechanism from the "hidden masses" that are particularly characteristic of Hertz's framework. This issue seemed especially glaring given the expectation that Hertz's work might lead to a model of the underlying workings of the ether. In this paper I seek an explanation for why Hertz seemed so unperturbed by the difficulties of constructing such a mechanism. In arriving at this explanation, I explore how the development of Hertz's image-theory of representation framed the project of Principles. The image-theory brings with it an austere view of the "essential content" of mechanics, only requiring a kind of structural isomorphism between symbolic representations and target phenomena. I argue that bringing this into view makes clear why Hertz felt no need to work out the kinds of mechanisms that many of his readers looked for. Furthermore, I argue that a crucial role of Hertz's hypothesis of hidden masses has been widely overlooked. Far from acting as a proposal for the underlying structure of the ether, I show that Hertz's hypothesis ruled out knowledge of such underlying structure.

  16. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    DEFF Research Database (Denmark)

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH solution O3 P is formed in a small...

  17. Dispersion Differences and Consistency of Artificial Periodic Structures.

    Science.gov (United States)

    Cheng, Zhi-Bao; Lin, Wen-Kai; Shi, Zhi-Fei

    2017-10-01

    Dispersion differences and consistency of artificial periodic structures, including phononic crystals, elastic metamaterials, as well as periodic structures composited of phononic crystals and elastic metamaterials, are investigated in this paper. By developing a K(ω) method, complex dispersion relations and group/phase velocity curves of both the single-mechanism periodic structures and the mixing-mechanism periodic structures are calculated at first, from which dispersion differences of artificial periodic structures are discussed. Then, based on a unified formulation, dispersion consistency of artificial periodic structures is investigated. Through a comprehensive comparison study, the correctness for the unified formulation is verified. Mathematical derivations of the unified formulation for different artificial periodic structures are presented. Furthermore, physical meanings of the unified formulation are discussed in the energy-state space.

  18. From Periodic Properties to a Periodic Table Arrangement

    Science.gov (United States)

    Besalú, Emili

    2013-01-01

    A periodic table is constructed from the consideration of periodic properties and the application of the principal components analysis technique. This procedure is useful for objects classification and data reduction and has been used in the field of chemistry for many applications, such as lanthanides, molecules, or conformers classification.…

  19. Periodic instantons and scattering amplitudes

    International Nuclear Information System (INIS)

    Khlebnikov, S.Yu.; Rubakov, V.A.; Tinyakov, P.G.

    1991-04-01

    We discuss the role of periodic euclidean solutions with two turning points and zero winding number (periodic instantons) in instanton induced processes below the sphaleron energy E sph . We find that the periodic instantons describe certain multiparticle scattering events leading to the transitions between topologically distinct vacua. Both the semiclassical amplitudes and inital and final states of these transitions are determined by the periodic instantons. Furthermore, the corresponding probabilities are maximal among all states of given energy. We show that at E ≤ E sph , the periodic instantons can be approximated by infinite chains of ordinary instantons and anti-instantons, and they naturally emerge as deformations of the zero energy instanton. In the framework of 2d abelian Higgs model and 4d electroweak theory we show, however, that there is not obvious relation between periodic instantons and two-particle scattering amplitudes. (orig.)

  20. Holonomic systems for period mappings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jingyue, E-mail: jychen@brandeis.edu [Department of Mathematics, Brandeis University, Waltham, MA 02454 (United States); Huang, An, E-mail: anhuang@math.harvard.edu [Department of Mathematics, Harvard University, Cambridge, MA 02138 (United States); Lian, Bong H., E-mail: lian@brandeis.edu [Department of Mathematics, Brandeis University, Waltham, MA 02454 (United States)

    2015-09-15

    Period mappings were introduced in the sixties [4] to study variation of complex structures of families of algebraic varieties. The theory of tautological systems was introduced recently [7,8] to understand period integrals of algebraic manifolds. In this paper, we give an explicit construction of a tautological system for each component of a period mapping. We also show that the D-module associated with the tautological system gives rise to many interesting vanishing conditions for period integrals at certain special points of the parameter space.

  1. Microprocessor controlled digital period meter

    International Nuclear Information System (INIS)

    Keefe, D.J.; McDowell, W.P.; Rusch, G.K.

    1980-01-01

    A microprocessor controlled digital period meter has been developed and tested operationally on a reactor at Argonne National Laboratory. The principle of operation is the mathematical relationship between asymptotic periods and pulse counting circuitry. This relationship is used to calculate and display the reactor periods over a range of /plus or minus/1 second to /plus or minus/999 seconds. The time interval required to update each measurement automatically varies from 8 seconds at the lowest counting rates to 2 seconds at higher counting rates. The paper will describe hardware and software design details and show the advantages of this type of Period Meter over the conventional circuits. 1 ref

  2. Gene Expression Profiling in the Pituitary Gland of Laying Period and Ceased Period Huoyan Geese

    Directory of Open Access Journals (Sweden)

    Xinhong Luan

    2013-07-01

    Full Text Available Huoyan goose is a Chinese local breed famous for its higher laying performance, but the problems of variety degeneration have emerged recently, especially a decrease in the number of eggs laid. In order to better understand the molecular mechanism that underlies egg laying in Huoyan geese, gene profiles in the pituitary gland of Huoyan geese taken during the laying period and ceased period were investigated using the suppression subtractive hybridization (SSH method. Total RNA was extracted from pituitary glands of ceased period and laying period geese. The cDNA in the pituitary glands of ceased geese was subtracted from the cDNA in the pituitary glands of laying geese (forward subtraction; the reverse subtraction was also performed. After sequencing and annotation, a total of 30 and 24 up and down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These genes mostly related to biosynthetic process, cellular nitrogen compound metabolic process, transport, cell differentiation, cellular protein modification process, signal transduction, small molecule metabolic process. Furthermore, eleven genes were selected for further analyses by quantitative real-time PCR (qRT-PCR. The qRT-PCR results for the most part were consistent with the SSH results. Among these genes, Synaptotagmin-1 (SYT1 and Stathmin-2 (STMN2 were substantially over-expressed in laying period compared to ceased period. These results could serve as an important reference for elucidating the molecular mechanism of higher laying performance in Huoyan geese.

  3. Fracture Mechanics

    International Nuclear Information System (INIS)

    Jang, Dong Il; Jeong, Gyeong Seop; Han, Min Gu

    1992-08-01

    This book introduces basic theory and analytical solution of fracture mechanics, linear fracture mechanics, non-linear fracture mechanics, dynamic fracture mechanics, environmental fracture and fatigue fracture, application on design fracture mechanics, application on analysis of structural safety, engineering approach method on fracture mechanics, stochastic fracture mechanics, numerical analysis code and fracture toughness test and fracture toughness data. It gives descriptions of fracture mechanics to theory and analysis from application of engineering.

  4. Forward Period Analysis Method of the Periodic Hamiltonian System.

    Directory of Open Access Journals (Sweden)

    Pengfei Wang

    Full Text Available Using the forward period analysis (FPA, we obtain the period of a Morse oscillator and mathematical pendulum system, with the accuracy of 100 significant digits. From these results, the long-term [0, 1060] (time unit solutions, ranging from the Planck time to the age of the universe, are computed reliably and quickly with a parallel multiple-precision Taylor series (PMT scheme. The application of FPA to periodic systems can greatly reduce the computation time of long-term reliable simulations. This scheme provides an efficient way to generate reference solutions, against which long-term simulations using other schemes can be tested.

  5. Detecting periodicities with Gaussian processes

    Directory of Open Access Journals (Sweden)

    Nicolas Durrande

    2016-04-01

    Full Text Available We consider the problem of detecting and quantifying the periodic component of a function given noise-corrupted observations of a limited number of input/output tuples. Our approach is based on Gaussian process regression, which provides a flexible non-parametric framework for modelling periodic data. We introduce a novel decomposition of the covariance function as the sum of periodic and aperiodic kernels. This decomposition allows for the creation of sub-models which capture the periodic nature of the signal and its complement. To quantify the periodicity of the signal, we derive a periodicity ratio which reflects the uncertainty in the fitted sub-models. Although the method can be applied to many kernels, we give a special emphasis to the Matérn family, from the expression of the reproducing kernel Hilbert space inner product to the implementation of the associated periodic kernels in a Gaussian process toolkit. The proposed method is illustrated by considering the detection of periodically expressed genes in the arabidopsis genome.

  6. Scheduling periodic tasks with slack

    NARCIS (Netherlands)

    Korst, J.H.M.; Aarts, E.H.L.; Lenstra, J.K.

    1997-01-01

    We consider the problem of nonpreemptively scheduling periodic tasks on a minimum number of identical processors, assuming that some slack is allowed in the time between successive executions of a periodic task. We prove that the problem is NP-hard in the strong sense. Necessary and sufficient

  7. Rationalization of Comet Halley's periods

    Science.gov (United States)

    Belton, Michael J. S.

    1990-01-01

    The sense of long axis orientation of Comet Halley during the Vega 1 encounter must be reversed from that deduced by Sagdeev et al. (1986) in order to harmonize the comet nucleus' Vega/Giotto-observed orientations with periodicities extracted from time-series brightness data. It is also demonstrated that Vega/Giotto observations can be satisfied by either a 2.2- or 3.7-day long-axis free precession period. A novel Fourier algorithm is used to reanalyze five independent data sets; strong evidence is adduced for periods harmonically related to a 7.4-day period. The preferred candidate models for Halley's nuclear rotation are characterized by a long-axis precession period of 3.7 days.

  8. Orbital periods of recurrent novae

    International Nuclear Information System (INIS)

    Schaefer, B.E.

    1990-01-01

    The class of recurrent novae (RN) with thermonuclear runaways contains only three systems (T Pyx, U Sco, and V394 CrA), for which no orbital periods are known. This paper presents a series of photometric observations where the orbital periods for all three systems are discovered. T Pyx is found to have sinusoidal modulation with an amplitude of 0.08 mag and a period of 2.3783 h (with a possible alias of 2.6403 h). U Sco is found to be an eclipsing system with an eclipse amplitude of roughly 1.5 mag and an orbital period of 1.2344 days. V394 CrA is found to have sinusoidal modulation with an amplitude of 0.5 mag and a period of 0.7577 days. Thus two out of three RN with thermonuclear runaways (or five out of six for all RN) have evolved companions. 16 refs

  9. Chaos to periodicity and periodicity to chaos by periodic perturbations in the Belousov-Zhabotinsky reaction

    International Nuclear Information System (INIS)

    Li Qianshu; Zhu Rui

    2004-01-01

    A three-variable model of the Belousov-Zhabotinsky reaction system subject to external sinusoidal perturbations is investigated by means of frequency spectrum analysis. In the period-1 window of the model, the transitions from periodicity to chaos are observed; in the chaotic window, the transitions from chaos to periodicity are found. The former might be understood by the circle map of two coupled oscillators, and the latter is partly explained by the resonance between the main frequency of the chaos and the frequency of the external periodic perturbations

  10. Electromagnetic radiation of electrons in periodic structures

    International Nuclear Information System (INIS)

    Potylitsyn, Alexander Petrovich

    2011-01-01

    Periodic magnetic structures (undulators) are widely used in accelerators to generate monochromatic undulator radiation (UR) in the range from far infrared to the hard X-ray region. Another periodic crystalline structure is used to produce quasimonochromatic polarized photon beams via the coherent bremsstrahlung mechanism (CBS). Due to such characteristics as monochromaticity, polarization and adjustability, these types of radiation is of large interest for applied and basic research of accelerator-emitted radiation. The book provides a detailed overview of the fundamental principles behind electromagnetic radiation emitted from accelerated charged particles (e.g. UR, CBS, radiation of fast electrons in Laser flash fields) as well as a unified description of relatively new radiation mechanisms which attracted great interest in recent years. This are the so-called polarization radiation excited by the Coulomb field of incident particles in periodic structures, parametric X-rays, resonant transition radiation and the Smith-Purcell effect. Characteristics of such radiation sources and perspectives of their usage are discussed. The recent experimental results as well as their interpretation are presented. (orig.)

  11. Iraqi architecture in mogul period

    Directory of Open Access Journals (Sweden)

    Hasan Shatha

    2018-01-01

    Full Text Available Iraqi architecture have many periods passed through it until now, each on from these periods have it is architectural style, also through time these styles interacted among us, to creating kind of space forming, space relationships, and architectural elements (detailed treatments, the research problem being from the multi interacted architectural styles causing some of confused of general characteristic to every style, that we could distinguish by it. Research tries to study architecture style through Mogul Conquest to Baghdad. Aim of research follow main characteristic for this architectural style in the Mogul periods on the level of form, elements, and treatments. Research depending on descriptive and analytical all buildings belong to this period, so from analyzing there style by, general form for building, architectural elements, and it architectural treatment, therefore; repeating this procedures to every building we get some similarities, from these similarities we can making conclusion about pure characteristic of the style of these period. Other side, we also discover some Dissimilar in the building periods, these will lead research to make what interacting among styles in this period, after all that we can drew clearly main characteristic of Architectural Style for Mogul Conquest in Baghdad

  12. The Periodic Table in Croatia

    Directory of Open Access Journals (Sweden)

    Raos, N.

    2011-12-01

    Full Text Available The Croatian (Yugoslav Academy of Sciences and Arts was the first academy to elect D. I. Mendeleev as its honorary member (1882, whereas the periodic table of the elements has been taught regularly at the Zagreb University since 1888. The early interest of Croatian chemists in the periodic table should be attributed primarily to their pan-Slavic attitude, particularly as proof that Slavic people were able to produce "their own Newtons" (M. V. Lomonosov and D. I. Mendeleev. Such enthusiastic views, however, did not help in analyzing the contribution of Mendeleev and other scientists to the discovery and development of the periodic table of the elements.

  13. An Alternate Graphical Representation of Periodic table of Chemical Elements

    OpenAIRE

    Abubakr, Mohd

    2009-01-01

    Periodic table of chemical elements symbolizes an elegant graphical representation of symmetry at atomic level and provides an overview on arrangement of electrons. It started merely as tabular representation of chemical elements, later got strengthened with quantum mechanical description of atomic structure and recent studies have revealed that periodic table can be formulated using SO(4,2)* SU(2) group. IUPAC, the governing body in Chemistry, doesn't approve any periodic table as a standard...

  14. Topological imprint for periodic orbits

    International Nuclear Information System (INIS)

    Martín, Jesús San; Moscoso, Ma José; Gómez, A González

    2012-01-01

    The more self-crossing points an orbit has the more complex it is. We introduce the topological imprint to characterize crossing points and focus on the period-doubling cascade. The period-doubling cascade topological imprint determines the topological imprint for orbits in chaotic bands. In addition, there is a closer link between this concept and the braids studied by Lettelier et al (2000 J. Phys. A: Math. Gen. 33 1809–25). (paper)

  15. Episodic spontaneous hypothermia: a periodic childhood syndrome.

    Science.gov (United States)

    Ruiz, Cynthia; Gener, Blanca; Garaizar, Carmen; Prats, José M

    2003-04-01

    Episodic spontaneous hypothermia is an infrequent disorder, with unknown pathogenic mechanisms. A systemic cause or underlying brain lesion has not been found for the disease. We report four new patients, 3-9 years old, with episodic hypothermia lower than 35 degrees C, marked facial pallor, and absent shivering. The episodes could last a few hours or four days, and recurred once a week or every 2-3 months. Two patients also demonstrated bradycardia, mild hypertension, and somnolence during the events; in one of them, profuse sweating was also a feature, and all four presented with either headache, a periodic childhood syndrome, or both (recurrent abdominal pain, cyclic vomiting, or vertigo). Three patients reported a family history of migraine. Neurologic examination, endocrine function, and imaging studies were normal. Migraine prophylactic therapy was of moderate efficacy. Spontaneous resolution was observed in one patient. The clinical characteristics of the syndrome allow for its inclusion as a childhood periodic syndrome related to migraine.

  16. Puzzling Mechanisms

    Science.gov (United States)

    van Deventer, M. Oskar

    2009-01-01

    The basis of a good mechanical puzzle is often a puzzling mechanism. This article will introduce some new puzzling mechanisms, like two knots that engage like gears, a chain whose links can be interchanged, and flat gears that do not come apart. It illustrates how puzzling mechanisms can be transformed into real mechanical puzzles, e.g., by…

  17. Commuting periodic operators and the periodic Wigner function

    International Nuclear Information System (INIS)

    Zak, J

    2004-01-01

    Commuting periodic operators (CPO) depending on the coordinate x-hat and the momentum p-hat operators are defined. The CPO are functions of the two basic commuting operators exp(i x-hat 2π/a) and exp(i/h p-hat a), with a being an arbitrary constant. A periodic Wigner function (PWF) w(x, p) is defined and it is shown that it is applicable in a normal expectation value calculation to the CPO, as done in the original Wigner paper. Moreover, this PWF is non-negative everywhere, and it can therefore be interpreted as an actual probability distribution. The PWF w(x, p) is shown to be given as an expectation value of the periodic Dirac delta function in the phase plane. (letter to the editor)

  18. Marginal elasticity of periodic triangulated origami

    Science.gov (United States)

    Chen, Bryan; Sussman, Dan; Lubensky, Tom; Santangelo, Chris

    Origami, the classical art of folding paper, has inspired much recent work on assembling complex 3D structures from planar sheets. Origami, and more generally hinged structures with rigid panels, where all faces are triangles have special properties due to having a bulk balance of mechanical degrees of freedom and constraints. We study two families of periodic triangulated origami structures, one based on the Miura ori and one based on a kagome-like pattern due to Ron Resch. We point out the consequences of the balance of degrees of freedom and constraints for these ''metamaterial plates'' and show how the elasticity can be tuned by changing the unit cell geometry.

  19. Centroid motion in periodically focused beams

    International Nuclear Information System (INIS)

    Moraes, J.S.; Pakter, R.; Rizzato, F.B.

    2005-01-01

    The role of the centroid dynamics in the transport of periodically focused particle beams is investigated. A Kapchinskij-Vladimirskij equilibrium distribution for an off-axis beam is derived. It is shown that centroid and envelope dynamics are uncoupled and that unstable regions for the centroid dynamics overlap with previously stable regions for the envelope dynamics alone. Multiparticle simulations validate the findings. The effects of a conducting pipe encapsulating the beam are also investigated. It is shown that the charge induced at the pipe may generate chaotic orbits which can be detrimental to the adequate functioning of the transport mechanism

  20. Nanopublication beyond the sciences: the PeriodO period gazetteer

    Directory of Open Access Journals (Sweden)

    Patrick Golden

    2016-02-01

    Full Text Available The information expressed in humanities datasets is inextricably tied to a wider discursive environment that is irreducible to complete formal representation. Humanities scholars must wrestle with this fact when they attempt to publish or consume structured data. The practice of “nanopublication,” which originated in the e-science domain, offers a way to maintain the connection between formal representations of humanities data and its discursive basis. In this paper we describe nanopublication, its potential applicability to the humanities, and our experience curating humanities nanopublications in the PeriodO period gazetteer.

  1. Periodic testing in operative action

    International Nuclear Information System (INIS)

    Larm, T.

    2005-01-01

    Periodic testing forms a remarkable part of the regular work tasks of the shift crew. Testing is generally carried out beside the daily monitoring and control work. Even remarkable plant related differences may occur in the procedures and routines used in periodic testing. The goal is still always the same, to regularly ensure that the systems and equipment are in working order according to their design. This presentation studies with examples the execution and scope of periodic testing as well as the routines and procedures used in the testing in Loviisa power plant. The presentation is based on the testing procedures of Loviisa power plant and the aim is not to compare them to the procedures of other plants. The scope of periodic testing has increased and the routines and procedures have been developed as the operation experience has increased. The assessment of the need of periodic testing and the consideration of the practical execution possibilities should be a part of the plant's planning phase as a part of the planning process. (orig.)

  2. A Study on Affect Mechanism of Employment Quality in the New Period in China:An Empirical Analysis Based on Survey Data%我国新时期个人就业质量影响因素研究--基于调查数据的实证分析

    Institute of Scientific and Technical Information of China (English)

    苏丽锋; 陈建伟

    2015-01-01

    从提升个人就业质量的视角出发,文章利用调查数据,通过多个指标对我国新时期个人就业质量进行了比较分析,并构建了包含个人就业满意度信息的就业质量指标,利用有序Logit模型对我国新时期个人就业质量的主要影响机制进行了实证分析。结果表明,劳动报酬因素对提升就业质量的作用明显;在工作时间因素中,工作生活平衡度对个人就业质量具有更为重要的影响;在职业发展方面,如果工作与专业匹配度越高,则劳动者的就业质量就越高;职业尊重因素的回归结果表明,所从事职业的受尊重程度,已成为新时期影响我国劳动者个人就业质量的最为重要的因素。该研究对我国制定新时期劳动力市场政策,实现更高质量就业目标具有现实意义。%From the point of view of improving employment quality , this article analyzed the employment quality of our country through a number of indicators using the survey data . We constructed an employment quality index containing personal job satisfaction information and tested empirically the main effecting mechanism to the employment quality through ordered Logit Model . The study found that the factors of labor remuneration significantly enhance the quality of employment .The balance between work and life has an important influence on the working time factors.To career development , the employment quality will be higher if the matching degree between work and professional technique is higher .Then the regression results showed that the career respect factors affect the quality of employment in the new period of China significantly .This research would be important to develop the labor market in the new period and achieve a higher quality of employment .

  3. Inflation from periodic extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Higaki, Tetsutaro [Department of Physics, Keio University, Kanagawa 223-8522 (Japan); Tatsuta, Yoshiyuki, E-mail: thigaki@rk.phys.keio.ac.jp, E-mail: y_tatsuta@akane.waseda.jp [Department of Physics, Waseda University, Tokyo 169-8555 (Japan)

    2017-07-01

    We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra dimension can have a periodicity, there will appear (quasi-)periodic functions under transformations of moduli of the extra dimensions in low energy scales. Such a periodic property can lead to a UV completion of so-called multi-natural inflation model where inflaton potential consists of a sum of multiple sinusoidal functions with a decay constant smaller than the Planck scale. As an illustration, we construct a SUSY breaking model, and then show that such an inflaton potential can be generated by a sum of world sheet instantons in intersecting brane models on extra dimensions containing orbifold. We show also predictions of cosmic observables by numerical analyzes.

  4. Periodicity, the Canon and Sport

    Directory of Open Access Journals (Sweden)

    Thomas F. Scanlon

    2015-10-01

    Full Text Available The topic according to this title is admittedly a broad one, embracing two very general concepts of time and of the cultural valuation of artistic products. Both phenomena are, in the present view, largely constructed by their contemporary cultures, and given authority to a great extent from the prestige of the past. The antiquity of tradition brings with it a certain cachet. Even though there may be peripheral debates in any given society which question the specifics of periodization or canonicity, individuals generally accept the consensus designation of a sequence of historical periods and they accept a list of highly valued artistic works as canonical or authoritative. We will first examine some of the processes of periodization and of canon-formation, after which we will discuss some specific examples of how these processes have worked in the sport of two ancient cultures, namely Greece and Mesoamerica.

  5. Periodicity and repeatability in data

    Science.gov (United States)

    Southwood, D.

    Using magnetic data from the first two years in Saturn orbit, the basic periodicity of apparent is examined with the aim of elucidating the `cam' shaft model of Espinosa et al. (2003) identifying the nature of the `cam' and giving a definitive period for its rotation. An initial hypothesis, supported by the spectral analysis of analysis of the first 8 months in orbit Gianpieri et al. (2006), is made that the source of the period is linked to something inside the planet and therefore that the source inertia means that the period effectively does not change over the 2 years. Moreover one expects that the source phase is fixed. Using this approach, not only can the period identified by spectral analysis (647.1 + 0.6 min.) be verified but also by phase analysis between successive passes over the 2 years the period can be refined to 647.6 + 0.1 min. The signal itself is remarkably reproducible from pass to pass. It appears in all three components of the field and its polarisation is unambiguously not attributable to direct detection of an internal field. Not only does the signal not decay rapidly with distance from the planet, but although it has the m=1 symmetry of a tilted dipole, the field lines diverge from the planet indicating an exterior source. This feature led to the `cam' model. The polarisation and comparisons of passes with different latitude profiles show a surprising north-south symmetry in the azimuthal field. The absence of asymmetry with respect to the magnetic equator rules out a direct magnetospheric-ionospheric interaction source. Accordingly, it is proposed that the basic `cam' effect is generated by a single hemisphere anomaly which creates hemisphere to hemisphere field aligned currents. The existence of Saturn phase related anomaly appears to produce a basic asymmetry in the inner magnetosphere that sets the phase of both an inflowing and outflowing sector in a rotating circulation system.

  6. An improved test for periodicity

    International Nuclear Information System (INIS)

    Davies, S.R.

    1990-01-01

    I discuss two widely used methods of testing for periodicity, phase dispersion minimization and epoch-folding. Using an analysis of variance approach, I demonstrate the close relationship between these two methods. I also show that the significance test sometimes used in phase dispersion minimization is statistically inaccurate, and that the test used in epoch-folding is an approximation valid only for large sample sizes. I propose a new test statistic, applicable to either epoch-folding or PDM, which is statistically sound for all sample sizes, and which is also more sensitive to periodicity than the test statistics previously used with these two methods. (author)

  7. Sigmoid Volvulus Complicating Postpartum Period

    Directory of Open Access Journals (Sweden)

    Kelsey E. Ward

    2017-01-01

    Full Text Available Background. Sigmoid volvulus is a rare complication of pregnancy and the puerperium. Case. A 19-year-old patient, gravida 1 para 0 at 41 0/7 weeks of gestation, admitted for late-term induction of labor underwent an uncomplicated primary low transverse cesarean delivery for arrest of descent. Her postoperative period was complicated by sudden onset of abdominal pain and the ultimate diagnosis of sigmoid volvulus. Conclusion. Prompt surgical evaluation of an acute abdomen in the postpartum period is essential; delayed diagnosis and treatment can lead to significant maternal morbidity and mortality.

  8. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  9. Availability of periodically tested systems

    International Nuclear Information System (INIS)

    Signoret, J.P.

    1979-01-01

    There is at the present time a need in accurate models to asess the availability of periodically tested stand-by systems. This paper shows how to improve the well known 'saw-tooth curve' model in order to take into account various reliability parameters. A model is developed to assess the pointwise and the mean availabilities of periodically tested stand-by systems. Exact and approxination formulae are given. In addition, the model developed herein leads to optimize the test interval in order to minimize the mean unavailability. A safety diesel in a nuclear power plant is given as an example

  10. Effect of the period of extrinsic mechanical compression following sclerotherapy in veins in rabbit ears Efeito do tempo da compressão mecânica extrínseca após escleroterapia em veias de orelhas de coelhos

    Directory of Open Access Journals (Sweden)

    Cláudio Santana Ivo

    2011-06-01

    Full Text Available PURPOSE: Research whether a post-sclerotherapy venous compression period of up to 120 hours is sufficient to avoid reperfusion in treated veins; whether there is a relationship between the inflammatory intensity in venous walls and adjacent tissue and the size of venous thrombosis; whether the intensity of the post-sclerotherapy inflammation varies with the period of compression; whether there is a relationship between the presence of hemosiderin in the tissues adjacent to the sclerosing blood vessels and venous blood clots. METHODS: Twenty eight rabbits, all male, were utilized, distributed into four groups (0, 24, 72 and 120. All the animals were administered with 0.25 ml of 1% polidoconal solution and, as a control, 0.25 ml of 0.9% sodium chloride solution in the marginal dorsal vein of the right and left ears, respectively. Mechanical compression was applied to the perfused stretch of the vein, except for the animals in group 0. The period of compression varied from 0 to 120 hours in the groups. An anatomopathological examination of the section of the right and left marginal dorsal veins of all the animals was conducted. RESULTS: There was no significant difference among the various compression periods, both in terms of the degree of vein thrombosis and in the inflammatory intensity in both ears of the various groups. A positive and significant correlation was observed between the inflammatory intensity and the size of the thrombus and in the occurrence of thrombi and hemosiderin. CONCLUSIONS: A compression period of up to 120 hours is not sufficient to prevent reperfusion in sclerosing blood vessels. The intensity of tissue inflammation is related to the size of the thrombus, but not to the compression period. The presence of hemosiderin in the tissues adjacent to the vessels subjected to sclerosis is related to the presence of venous coagulation.OBJETIVO: Pesquisar se o tempo de compressão venosa de até 120 horas pós-escleroterapia

  11. Periodic and quasiperiodic revivals in periodically driven interacting quantum systems

    Science.gov (United States)

    Luitz, David J.; Lazarides, Achilleas; Bar Lev, Yevgeny

    2018-01-01

    Recently it has been shown that interparticle interactions generically destroy dynamical localization in periodically driven systems, resulting in diffusive transport and heating. In this Rapid Communication we rigorously construct a family of interacting driven systems which are dynamically localized and effectively decoupled from the external driving potential. We show that these systems exhibit tunable periodic or quasiperiodic revivals of the many-body wave function and thus of all physical observables. By numerically examining spinless fermions on a one-dimensional lattice we show that the analytically obtained revivals of such systems remain stable for finite systems with open boundary conditions while having a finite lifetime in the presence of static spatial disorder. We find this lifetime to be inversely proportional to the disorder strength.

  12. Cosmophysical periods in European history

    International Nuclear Information System (INIS)

    Vladimirskij, B.M.; Kislovskij, L.D.

    1995-01-01

    In social systems there are rhythms synchronised by cosmical periods. These rhythms have partly biological origin. Some natural cycles also might influence upon historical processes (as such as climatic and epidemical). The analysis of the literature shows that there is rhythmic component in European history where solar activity cycles -11 and 340 years are presented. 17 refs., 2 tabs

  13. Genius of the periodic table

    International Nuclear Information System (INIS)

    1969-01-01

    'Isn't it the work of a genius!' exclaimed Academician V.I. Spitsyn, USSR, a member of the Scientific Advisory Committee when talking to an Agency audience in January. His listeners shared his enthusiasm. Academician Spitsyn was referring to the first formulation a hundred years ago by Professor Dmitry I. Mendeleyev of the Periodic Law of Elements. (author)

  14. Glass Waveguides for Periodic Poling

    DEFF Research Database (Denmark)

    Fage-Pedersen, Jacob; Jacobsen, Rune Shim; Kristensen, Martin

    2005-01-01

    Planar silica-based waveguide devices have been developed for second-harmonic generation by poling with periodic electrodes. We show that detrimental charge transport can occur along interfaces, but with proper choice of fabrication, high-quality devices are obtained....

  15. Periodic linear differential stochastic processes

    NARCIS (Netherlands)

    Kwakernaak, H.

    1975-01-01

    Periodic linear differential processes are defined and their properties are analyzed. Equivalent representations are discussed, and the solutions of related optimal estimation problems are given. An extension is presented of Kailath and Geesey’s [1] results concerning the innovations representation

  16. Model selection in periodic autoregressions

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); R. Paap (Richard)

    1994-01-01

    textabstractThis paper focuses on the issue of period autoagressive time series models (PAR) selection in practice. One aspect of model selection is the choice for the appropriate PAR order. This can be of interest for the valuation of economic models. Further, the appropriate PAR order is important

  17. Periodic progress report, 6 months

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Nielsen, Jakob Skov

    This is the first progress report of the BriteEuram project named "High Power Laser Cutting for Heavy Industry" ("Powercut"). The report contains a summary of the objectives of the first period, an overview of the technical progress, a comparison between the planed and the accomplished work...

  18. Quantum mechanics

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The book is on quantum mechanics. The emphasis is on the basic concepts and the methodology. The chapters include: Breakdown of classical concepts; Quantum mechanical concepts; Basic postulates of quantum mechanics; solution of problems in quantum mechanics; Simple harmonic oscillator; and Angular Momentum

  19. Continuum mechanics

    CERN Document Server

    Spencer, A J M

    2004-01-01

    The mechanics of fluids and the mechanics of solids represent the two major areas of physics and applied mathematics that meet in continuum mechanics, a field that forms the foundation of civil and mechanical engineering. This unified approach to the teaching of fluid and solid mechanics focuses on the general mechanical principles that apply to all materials. Students who have familiarized themselves with the basic principles can go on to specialize in any of the different branches of continuum mechanics. This text opens with introductory chapters on matrix algebra, vectors and Cartesian ten

  20. Autoinflammatory Diseases with Periodic Fevers.

    Science.gov (United States)

    Sag, Erdal; Bilginer, Yelda; Ozen, Seza

    2017-07-01

    One purpose of this review was to raise awareness for the new autoinflammatory syndromes. These diseases are increasingly recognized and are in the differential diagnosis of many disease states. We also aimed to review the latest recommendations for the diagnosis, management, and treatment of these patients. Familial Mediterranean fever (FMF), cryopyrin-associated periodic syndrome (CAPS), tumor necrosis factor receptor-associated periodic fever syndrome (TRAPS), and hyperimmunoglobulinemia D and periodic fever syndrome/mevalonate kinase deficiency (HIDS/MVKD) are the more common autoinflammatory diseases that are characterized by periodic fevers and attacks of inflammation. Recently much collaborative work has been done to understand the characteristics of these patients and to develop recommendations to guide the physicians in the care of these patients. These recent recommendations will be summarized for all four diseases. FMF is the most common periodic fever disease. We need to further understand the pathogenesis and the role of single mutations in the disease. Recently, the management and treatment of the disease have been nicely reviewed. CAPS is another interesting disease associated with severe complications. Anti-interleukin-1 (anti-IL-1) treatment provides cure for these patients. TRAPS is characterized by the longest delay in diagnosis; thus, both pediatricians and internists should be aware of the characteristic features and the follow-up of these patients. HIDS/MVKD is another autoinflammatory diseases characterized with fever attacks. The spectrum of disease manifestation is rather large in this disease, and we need further research on biomarkers for the optimal management of these patients.

  1. Vertebrate fauna of the Roman period, migrations period and Medieval period in Vojvodina (Serbia

    Directory of Open Access Journals (Sweden)

    Radmanović Darko P.

    2014-01-01

    Full Text Available Based on current published and unpublished research results, a total of 16 vertebrate species members of mammal (Mammalia, bird (Aves and osteichthyes (Osteichthyes classes have been registered at 11 archaeological sites from the Roman Period in Vojvodina. Mammals dominate with 12 species and one genus, birds are present with 3 species, and osteichthyes with one. From the Migration Period, at 9 sites, 22 vertebrate species have been registered, of which 13 species and one genus of mammals, 4 species and one genus of birds, and 5 species from the Osteichthyes class. At 8 sites from the Medieval Period, 16 vertebrate species have been registered. Mammals are the most numerous class with 10 species and one genus, while birds are present with 4 species and one genus. Furthermore, two species of osteichthyes have also been registered.

  2. Performance of the periodic pulse technique--4. Periodic pulse reaction kinetics of oxidative dehydrogenation of isobutyraldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, T.; Ii, M.; Murakami, Y.

    1980-07-01

    The periodic pulse method was used to study the reaction mechanism and kinetics of the oxidative dehydrogenation of isobutyraldehyde (IBA) by following the formation rates of methacrolein (MA), carbon monoxide and dioxide (CO/sub x/), and other products (P) as a function of pulse widths and reactant partial pressures at 350/sup 0/C over a 2:3 antimony oxide/molybdenum trioxide catalyst. The results were consistent with a mechanism according to which IBA reacts with oxygen retained by the catalyst to form MA, causing reduction of the catalyst. The IBA also adsorbed on the surface as an oxygenated species which either reacted with gas-phase oxygen to form CO/sub x/ or desorbed as an oxygenated P. The reduced catalyst surface was reoxidized by oxygen adsorption. Implications of catalyst tailoring for increased MA yields by improving the redox mechanism and inhibiting the surface reactions, are discussed.

  3. Period of an Interrupted Pendulum

    Science.gov (United States)

    Miller, Bradley E.

    2002-11-01

    While demonstrating a classic conservation-of-energy problem to my AP Physics students, I became curious about the periodic motion that ensued for certain initial conditions. The original problem consists of releasing a mass at the end of a string from an initial position horizontal to the plane of a table. The string comes in contact with a peg some distance below the point where the string is attached at the top. One is asked to find what minimum fraction of the string's length should the peg be placed to have the mass complete a circle about the peg. However, when the mass is released from much lower heights, the system undergoes periodic motion that can be thought of as an interrupted pendulum.

  4. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  5. On nonlinear periodic drift waves

    International Nuclear Information System (INIS)

    Kauschke, U.; Schlueter, H.

    1990-09-01

    Nonlinear periodic drift waves are investigated on the basis of a simple perturbation scheme for both the amplitude and inverse frequency. The coefficients for the generation of the forced harmonics are derived, a nonlinear dispersion relation is suggested and a criterion for the onset of the modulational instability is obtained. The results are compared with the ones obtained with the help of a standard KBM-treatment. Moreover cnoidal drift waves are suggested and compared to an experimental observation. (orig.)

  6. Long Period Seismological Research Program

    Science.gov (United States)

    1974-10-31

    in central Asia as observed at the high-gain long- period sites. Preliminary results from observations at Chiang Mai (CHG) show that the complexity...Preliminary results from observations at Chiang Mai (CHG) show that the complexity of the surface wave signals from many events in the Tadzhik-Kirgiz...and receivers. A number of Interesting features can be illustrated by examining portions of three selsmograms recorded at Chiang Mai (CHO

  7. Mammalian cycles: internally defined periods and interaction-driven amplitudes

    Directory of Open Access Journals (Sweden)

    LR Ginzburg

    2015-08-01

    Full Text Available The cause of mammalian cycles—the rise and fall of populations over a predictable period of time—has remained controversial since these patterns were first observed over a century ago. In spite of extensive work on observable mammalian cycles, the field has remained divided upon what the true cause is, with a majority of opinions attributing it to either predation or to intra-species mechanisms. Here we unite the eigenperiod hypothesis, which describes an internal, maternal effect-based mechanism to explain the cycles’ periods with a recent generalization explaining the amplitude of snowshoe hare cycles in northwestern North America based on initial predator abundance. By explaining the period and the amplitude of the cycle with separate mechanisms, a unified and consistent view of the causation of cycles is reached. Based on our suggested theory, we forecast the next snowshoe hare cycle (predicted peak in 2016 to be of extraordinarily low amplitude.

  8. C-type period-doubling transition in nephron autoregulation

    DEFF Research Database (Denmark)

    Laugesen, Jakob Lund; Mosekilde, Erik; Holstein-Rathlou, Niels-Henrik

    2011-01-01

    The functional units of the kidney, called nephrons, utilize mechanisms that allow the individual nephron to regulate the incoming blood flow in response to fluctuations in the arterial pressure. This regulation tends to be unstable and to generate self-sustained oscillations, period-doubling bif......The functional units of the kidney, called nephrons, utilize mechanisms that allow the individual nephron to regulate the incoming blood flow in response to fluctuations in the arterial pressure. This regulation tends to be unstable and to generate self-sustained oscillations, period......-doubling bifurcations, mode-locking and other nonlinear dynamic phenomena in the tubular pressures and flows. Using a simplified nephron model, the paper examines how the regulatory mechanisms react to an external periodic variation in arterial pressure near a region of resonance with one of the internally generated...

  9. Mechanical Ventilation

    Science.gov (United States)

    ... ventilation is a life support treatment. A mechanical ventilator is a machine that helps people breathe when ... to breathe enough on their own. The mechanical ventilator is also called a ventilator , respirator, or breathing ...

  10. Mechanical design

    CERN Document Server

    Risitano, Antonino

    2011-01-01

    METHODOLOGICAL STATEMENT OF ENGINEERING DESIGNApproaches to product design and developmentMechanical design and environmental requirementsPROPERTIES OF ENGINEERING MATERIALSMaterials for mechanical designCharacterization of metalsStress conditionsFatigue of materialsOptimum material selection in mechanical designDESIGN OF MECHANICAL COMPONENTS AND SYSTEMSFailure theoriesHertz theoryLubrificationShafts and bearingsSplines and keysSpringsFlexible machine elementsSpur gearsPress and shrink fitsPressure tubesCouplingsClutchesBrakes

  11. NLC Mechanical

    Science.gov (United States)

    text only Mechanical Systems.gif (14697 bytes) NLC Home Page NLC Technical SLAC Permanent Magnets Organization Overview The Mechanical Systems Group Organization is shown on the NLC Project Group Organization Chart (Next Linear Collider Technical Web Page). The Mechanical Systems Group operates on a matrixed

  12. Mechanical Kinesiology.

    Science.gov (United States)

    Barham, Jerry N.

    Mechanical kinesiology is defined as a study of the mechanical factors affecting human movement, i.e., applying the physical laws of mechanics to the study of human motor behavior. This textbook on the subject is divided into thirty lessons. Each lesson is organized into three parts: a part on the text proper; a part entitled "study…

  13. Mechanisms Design

    DEFF Research Database (Denmark)

    Restrepo-Giraldo, John Dairo

    2006-01-01

    Most products and machines involve some kind of controlled movement. From window casements to DVD players, from harbor cranes to the shears to prune your garden, all these machines require mechanisms to move. This course intends to provide the analytical and conceptual tools to design such mechan......Most products and machines involve some kind of controlled movement. From window casements to DVD players, from harbor cranes to the shears to prune your garden, all these machines require mechanisms to move. This course intends to provide the analytical and conceptual tools to design...... using criteria such as size, performance parameters, operation environment, etc. Content: Understanding Mechanisms Design (2 weeks) Definitions, mechanisms representations, kinematic diagrams, the four bar linkage, mobility, applications of mechanisms, types of mechanisms, special mechanisms, the design......: equations for various mechanisms. At the end of this module you will be able to analyze existing mechanisms and to describe their movement. Designing mechanisms (7 weeks) Type synthesis and dimensional synthesis, function generation, path generation, three precision points in multi-loop mechanisms...

  14. Pairs of dual periodic frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Goh, Say Song

    2012-01-01

    The time–frequency analysis of a signal is often performed via a series expansion arising from well-localized building blocks. Typically, the building blocks are based on frames having either Gabor or wavelet structure. In order to calculate the coefficients in the series expansion, a dual frame...... is needed. The purpose of the present paper is to provide constructions of dual pairs of frames in the setting of the Hilbert space of periodic functions L2(0,2π). The frames constructed are given explicitly as trigonometric polynomials, which allows for an efficient calculation of the coefficients...

  15. Periodic dynamics in queuing networks

    Energy Technology Data Exchange (ETDEWEB)

    Addabbo, Tommaso [Information Engineering Department, University of Siena, Via Roma 56, 53100 Siena (Italy)], E-mail: addabbo@dii.unisi.it; Kocarev, Ljupco [Macedonian Academy of Sciences and Arts, bul. Krste Misirkov 2, P.O. Box 428, 1000 Skopje, Republic of Macedonia (Macedonia, The Former Yugoslav Republic of)], E-mail: lkocarev@ucsd.edu

    2009-08-30

    This paper deals with state-dependent open Markovian (or exponential) queuing networks, for which arrival and service rates, as well as routing probabilities, may depend on the queue lengths. For a network of this kind, following Mandelbaum and Pats, we provide a formal definition of its associated fluid model, and we focus on the relationships which may occur between the network stochastic dynamics and the deterministic dynamics of its corresponding fluid model, particularly focusing on queuing networks whose fluid models have global periodic attractors.

  16. Periodic permanent magnet focused klystron

    Science.gov (United States)

    Ferguson, Patrick; Read, Michael; Ives, R Lawrence

    2015-04-21

    A periodic permanent magnet (PPM) klystron has beam transport structures and RF cavity structures, each of which has permanent magnets placed substantially equidistant from a beam tunnel formed about the central axis, and which are also outside the extent of a cooling chamber. The RF cavity sections also have permanent magnets which are placed substantially equidistant from the beam tunnel, but which include an RF cavity coupling to the beam tunnel for enhancement of RF carried by an electron beam in the beam tunnel.

  17. Forgiveness in the intertestamental period

    Directory of Open Access Journals (Sweden)

    Sang-Mong Lee

    2012-02-01

    Full Text Available The article suggests answers to the following questions: what are the characteristics of God�s forgiveness in the intertestamental literature and what connection do these characteristics have with the Old Testament? Important passages in the late Second Temple period that expose the characteristics of God�s forgiveness, such as certain Qumran texts (1QH 12:35�37, 1QH 13:2 and the Damascus Document 14:18�19, the writings of Philo and Josephus, the Apocrypha and the Pseudepigrapha, are investigated for this purpose.

  18. Image Segmentation Based on Period Difference of the Oscillation

    Institute of Scientific and Technical Information of China (English)

    王直杰; 张珏; 范宏; 柯克峰

    2004-01-01

    A new method for image segmentation based on pulse neural network is proposed. Every neuron in the network represents one pixel in the image and the network is locally connected.Each group of the neurons that correspond to each object synchronizes while different gronps of the neurons oscillate at different period. Applying this period difference,different objects are divided. In addition to simulation, an analysis of the mechanism of the method is presented in this paper.

  19. Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

    Science.gov (United States)

    McLaughlin, J. A.; Nakariakov, V. M.; Dominique, M.; Jelínek, P.; Takasao, S.

    2018-02-01

    Solar flare emission is detected in all EM bands and variations in flux density of solar energetic particles. Often the EM radiation generated in solar and stellar flares shows a pronounced oscillatory pattern, with characteristic periods ranging from a fraction of a second to several minutes. These oscillations are referred to as quasi-periodic pulsations (QPPs), to emphasise that they often contain apparent amplitude and period modulation. We review the current understanding of quasi-periodic pulsations in solar and stellar flares. In particular, we focus on the possible physical mechanisms, with an emphasis on the underlying physics that generates the resultant range of periodicities. These physical mechanisms include MHD oscillations, self-oscillatory mechanisms, oscillatory reconnection/reconnection reversal, wave-driven reconnection, two loop coalescence, MHD flow over-stability, the equivalent LCR-contour mechanism, and thermal-dynamical cycles. We also provide a histogram of all QPP events published in the literature at this time. The occurrence of QPPs puts additional constraints on the interpretation and understanding of the fundamental processes operating in flares, e.g. magnetic energy liberation and particle acceleration. Therefore, a full understanding of QPPs is essential in order to work towards an integrated model of solar and stellar flares.

  20. Central configurations, periodic orbits, and Hamiltonian systems

    CERN Document Server

    Llibre, Jaume; Simó, Carles

    2015-01-01

    The notes of this book originate from three series of lectures given at the Centre de Recerca Matemàtica (CRM) in Barcelona. The first one is dedicated to the study of periodic solutions of autonomous differential systems in Rn via the Averaging Theory and was delivered by Jaume Llibre. The second one, given by Richard Moeckel, focusses on methods for studying Central Configurations. The last one, by Carles Simó, describes the main mechanisms leading to a fairly global description of the dynamics in conservative systems. The book is directed towards graduate students and researchers interested in dynamical systems, in particular in the conservative case, and aims at facilitating the understanding of dynamics of specific models. The results presented and the tools introduced in this book include a large range of applications.

  1. Manipulating the Cellular Circadian Period of Arginine Vasopressin Neurons Alters the Behavioral Circadian Period.

    Science.gov (United States)

    Mieda, Michihiro; Okamoto, Hitoshi; Sakurai, Takeshi

    2016-09-26

    As the central pacemaker in mammals, the circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus is a heterogeneous structure consisting of multiple types of GABAergic neurons with distinct chemical identities [1, 2]. Although individual cells have a cellular clock driven by autoregulatory transcriptional/translational feedback loops of clock genes, interneuronal communication among SCN clock neurons is likely essential for the SCN to generate a highly robust, coherent circadian rhythm [1]. However, neuronal mechanisms that determine circadian period length remain unclear. The SCN is composed of two subdivisions: a ventral core region containing vasoactive intestinal peptide (VIP)-producing neurons and a dorsal shell region characterized by arginine vasopressin (AVP)-producing neurons. Here we examined whether AVP neurons act as pacemaker cells that regulate the circadian period of behavior rhythm in mice. The deletion of casein kinase 1 delta (CK1δ) specific to AVP neurons, which was expected to lengthen the period of cellular clocks [3-6], lengthened the free-running period of circadian behavior as well. Conversely, the overexpression of CK1δ specific to SCN AVP neurons shortened the free-running period. PER2::LUC imaging in slices confirmed that cellular circadian periods of the SCN shell were lengthened in mice without CK1δ in AVP neurons. Thus, AVP neurons may be an essential component of circadian pacemaker cells in the SCN. Remarkably, the alteration of the shell-core phase relationship in the SCN of these mice did not impair the generation per se of circadian behavior rhythm, thereby underscoring the robustness of the SCN network. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Discrete mechanics

    CERN Document Server

    Caltagirone, Jean-Paul

    2014-01-01

    This book presents the fundamental principles of mechanics to re-establish the equations of Discrete Mechanics. It introduces physics and thermodynamics associated to the physical modeling.  The development and the complementarity of sciences lead to review today the old concepts that were the basis for the development of continuum mechanics. The differential geometry is used to review the conservation laws of mechanics. For instance, this formalism requires a different location of vector and scalar quantities in space. The equations of Discrete Mechanics form a system of equations where the H

  3. Discrete mechanics

    International Nuclear Information System (INIS)

    Lee, T.D.

    1985-01-01

    This paper reviews the role of time throughout all phases of mechanics: classical mechanics, non-relativistic quantum mechanics, and relativistic quantum theory. As an example of the relativistic quantum field theory, the case of a massless scalar field interacting with an arbitrary external current is discussed. The comparison between the new discrete theory and the usual continuum formalism is presented. An example is given of a two-dimensional random lattice and its duel. The author notes that there is no evidence that the discrete mechanics is more appropriate than the usual continuum mechanics

  4. Global Magnetic Variability at Planetary Wave Periods

    Science.gov (United States)

    Forbes, J. M.; Behm, J.

    2017-12-01

    Planetary waves (PW) and PW-tide interactions are thought to introduce multi-day periodicities ( 2-20 days) in the electric fields and currents induced by the wind dynamo mechanism in the ionospheric E-region (ca. 100-150 km), and thus can provide important insights on coupling between the lower atmosphere and the ionosphere. Previous studies have used a relatively small subset of available data to infer the existence of these variations in ground magnetic measurements. In some cases connections were made with contemporaneous measurements of neutral wind dynamics. In the present work, we employ ground-based magnetometer data from over 100 stations from the INTERMAGNET network during 2009 to gain a global perspective on eastward- and westward-propagating and zonally-symmetric oscillations with PW periods. Our presentation describes how the unevenly-spaced global data are re-gridded onto an icosahedral grid prior to analysis, and assesses how gaps in the distribution of points across the grid affect extraction of some parts of the spectrum. Consideration is also given to possible contamination by recurrent magnetic activity at subharmonics of 27 days. The global evolution of several PW components during 2009 are depicted and interpreted.

  5. Periodic cavitation shedding in a cylindrical orifice

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, C.; Barber, T.; Milton, B.; Rosengarten, G. [University of New South Wales, School of Mechanical and Manufacturing Engineering, Sydney (Australia)

    2011-11-15

    Cavitation structures in a large-scale (D = 8.25 mm), plain orifice style nozzle within a unique experimental rig are investigated using high-speed visualisation and digital image processing techniques. Refractive index matching with an acrylic nozzle is achieved using aqueous sodium iodide for the test fluid. Cavitation collapse length, unsteady shedding frequency and spray angles are measured for cavitation conditions from incipient to supercavitation for a range of Reynolds numbers, for a fixed L/D ratio of 4.85. Periodic cavitation shedding was shown to occur with frequencies between 500 and 2,000 Hz for conditions in which cavitation occupied less than 30% of the nozzle length. A discontinuity in collapse length was shown to occur once the cavitation exceeded this length, coinciding with a loss of periodic shedding. A mechanism for this behaviour is discussed. Peak spray angles of approximately {theta} {approx} 14 were recorded for supercavitation conditions indicating the positive influence of cavitation bubble collapse on the jet atomisation process. (orig.)

  6. Origin of very-short orbital-period binary systems

    International Nuclear Information System (INIS)

    Miyaji, S.

    1983-01-01

    Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both X-ray close binaries and cataclysmic variables. Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of which belongs to any globular cluster, are too abundant to be explained by the capturing mechanism of a white dwarf. Therefore it seemed to be worthwhile to present an evolutionary scenario from an original binary system which can be applied for all VSOP binaries. (Auth.)

  7. Periodic weather and climate variations

    International Nuclear Information System (INIS)

    Ivanov, Vladimir V

    2002-01-01

    Variations in meteorological parameters are largely due to periodic processes and can be forecast for several years. Many such processes are related to astronomical factors such as the gravitational influences of the Moon and the Sun, and the modulation of solar irradiance by lunar and planetary motion. The Moon, Jupiter, and Venus have the strongest effect. These influences produce lines in the spectra of meteorological variations, which are combinations of the harmonics of the frequencies of revolution of the planets, the Earth, and the Moon around the Sun with the harmonics of the lunar revolution around the Earth. Due to frequency differences between the orbital and radial motions, fine spectral features of three types appear: line splitting, line-profile complications due to radial oscillations, and additional lines due to the combination of radial-oscillation frequencies with perturbation harmonics. (reviews of topical problems)

  8. The periodic table in Flatland

    International Nuclear Information System (INIS)

    Kibler, M.

    1995-01-01

    The D-dimensional Coulomb system serves as a starting point for generating generalized atomic shells. These shells are ordered according to a generalized Madelung rule in D dimensions. This rule together with an Aufbau Prinzip is applied to produce a D-dimensional periodic table. A model is developed to rationalize the ordering of the shells predicted by the generalized Madelung rule. This model is based on the introduction of an Hamiltonian, invariant under the q-deformed algebra U q (so(D)), that breaks down the SO (D + 1) dynamical symmetry of the hydrogen atom in D dimensions. The D = 2 case (Flatland) is investigated with some details. It is shown that the neutral atoms and the (moderately) positive ions correspond to the values q = 0.8 and q = 1, respectively, of the deformation parameter q. (authors). 55 refs

  9. A periodic table for cancer.

    Science.gov (United States)

    Epstein, Richard J

    2015-01-01

    Cancers exhibit differences in metastatic behavior and drug sensitivity that correlate with certain tumor-specific variables such as differentiation grade, growth rate/extent and molecular regulatory aberrations. In practice, patient management is based on the past results of clinical trials adjusted for these biomarkers. Here, it is proposed that treatment strategies could be fine-tuned upfront simply by quantifying tumorigenic spatial (cell growth) and temporal (genetic stability) control losses, as predicted by genetic defects of cell-cycle-regulatory gatekeeper and genome-stabilizing caretaker tumor suppressor genes, respectively. These differential quantifications of tumor dysfunction may in turn be used to create a tumor-specific 'periodic table' that guides rational formulation of survival-enhancing anticancer treatment strategies.

  10. Optimal ventilatory patterns in periodic breathing.

    Science.gov (United States)

    Ghazanshahi, S D; Khoo, M C

    1993-01-01

    The goal of this study was to determine whether periodic breathing (PB), which is highly prevalent during sleep at high altitudes, imposes physiological penalties on the respiratory system in the absence of any accompanying disease. Using a computer model of respiratory gas exchange, we compared the effects of a variety of PB patterns on the chemical and mechanical costs of breathing to those resulting from regular tidal breathing. Although PB produced considerable fluctuation in arterial blood gas tensions, for the same cycle-averaged ventilation, higher arterial oxygen saturation and lower arterial carbon dioxide levels were achieved. This result can be explained by the fact that the combination of large breaths and apnea in PB leads to a substantial reduction in dead space ventilation. At the same time, the savings in mechanical cost achieved by the respiratory muscles during apnea partially offset the increase during the breathing phase. Consequently, the "pressure cost," a criterion based on mean inspiratory pressure, was elevated only slightly, although the average work rate of breathing increased significantly. We found that, at extreme altitudes, PB patterns with clusters of 2 to 4 large breaths that alternate with apnea produce the highest arterial oxygenation levels and lowest pressure costs. The common occurrence of PB patterns with closely similar features has been reported in sleeping healthy sojourners at extreme altitudes. Taken together, these findings suggest that PB favors a reduction in the oxygen demands of the respiratory muscles and therefore may not be as detrimental as it is generally believed to be.

  11. Explore Stochastic Instabilities of Periodic Points by Transition Path Theory

    Science.gov (United States)

    Cao, Yu; Lin, Ling; Zhou, Xiang

    2016-06-01

    We consider the noise-induced transitions from a linearly stable periodic orbit consisting of T periodic points in randomly perturbed discrete logistic map. Traditional large deviation theory and asymptotic analysis at small noise limit cannot distinguish the quantitative difference in noise-induced stochastic instabilities among the T periodic points. To attack this problem, we generalize the transition path theory to the discrete-time continuous-space stochastic process. In our first criterion to quantify the relative instability among T periodic points, we use the distribution of the last passage location related to the transitions from the whole periodic orbit to a prescribed disjoint set. This distribution is related to individual contributions to the transition rate from each periodic points. The second criterion is based on the competency of the transition paths associated with each periodic point. Both criteria utilize the reactive probability current in the transition path theory. Our numerical results for the logistic map reveal the transition mechanism of escaping from the stable periodic orbit and identify which periodic point is more prone to lose stability so as to make successful transitions under random perturbations.

  12. Mechanical drawing

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Ho Seon; Lee, Geun Hui

    2004-04-15

    This book deals with how to read and draw the mechanical drawing, which includes the basic of drawing like purpose, kinds, and criterion, projection, special projection drawing, omission of the figure, section, and types of section, dimensioning method, writing way of allowable limit size, tolerance of regular size, parts list and assembling drawing, fitting, mechanical elements like screw, key, pin, rivet, spring, bearing, pipe, valve, welding, geometric tolerance and mechanical materials.

  13. Classical mechanics

    CERN Document Server

    Benacquista, Matthew J

    2018-01-01

    This textbook provides an introduction to classical mechanics at a level intermediate between the typical undergraduate and advanced graduate level. This text describes the background and tools for use in the fields of modern physics, such as quantum mechanics, astrophysics, particle physics, and relativity. Students who have had basic undergraduate classical mechanics or who have a good understanding of the mathematical methods of physics will benefit from this book.

  14. Mechanical science

    CERN Document Server

    Bolton, W C

    2013-01-01

    This book gives comprehensive coverage of mechanical science for HNC/HND students taking mechanical engineering courses, including all topics likely to be covered in both years of such courses, as well as for first year undergraduate courses in mechanical engineering. It features 500 problems with answers and 200 worked examples. The third edition includes a new section on power transmission and an appendix on mathematics to help students with the basic notation of calculus and solution of differential equations.

  15. Continuum Mechanics

    CERN Document Server

    Romano, Antonio

    2010-01-01

    This book offers a broad overview of the potential of continuum mechanics to describe a wide range of macroscopic phenomena in real-world problems. Building on the fundamentals presented in the authors' previous book, Continuum Mechanics using Mathematica(R), this new work explores interesting models of continuum mechanics, with an emphasis on exploring the flexibility of their applications in a wide variety of fields.Specific topics, which have been chosen to show the power of continuum mechanics to characterize the experimental behavior of real phenomena, include: * various aspects of nonlin

  16. Variable mechanical ventilation.

    Science.gov (United States)

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

  17. The physiological period length of the human circadian clock in vivo is directly proportional to period in human fibroblasts.

    Directory of Open Access Journals (Sweden)

    Lucia Pagani

    Full Text Available BACKGROUND: Diurnal behavior in humans is governed by the period length of a circadian clock in the suprachiasmatic nuclei of the brain hypothalamus. Nevertheless, the cell-intrinsic mechanism of this clock is present in most cells of the body. We have shown previously that for individuals of extreme chronotype ("larks" and "owls", clock properties measured in human fibroblasts correlated with extreme diurnal behavior. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have measured circadian period in human primary fibroblasts taken from normal individuals and, for the first time, compared it directly with physiological period measured in vivo in the same subjects. Human physiological period length was estimated via the secretion pattern of the hormone melatonin in two different groups of sighted subjects and one group of totally blind subjects, each using different methods. Fibroblast period length was measured via cyclical expression of a lentivirally delivered circadian reporter. Within each group, a positive linear correlation was observed between circadian period length in physiology and in fibroblast gene expression. Interestingly, although blind individuals showed on average the same fibroblast clock properties as sighted ones, their physiological periods were significantly longer. CONCLUSIONS/SIGNIFICANCE: We conclude that the period of human circadian behaviour is mostly driven by cellular clock properties in normal individuals and can be approximated by measurement in peripheral cells such as fibroblasts. Based upon differences among sighted and blind subjects, we also speculate that period can be modified by prolonged unusual conditions such as the total light deprivation of blindness.

  18. Dynamical diffraction in periodic multilayers

    CERN Document Server

    Sears, V F

    1997-01-01

    Exact reflectivity curves are calculated numerically for various periodic multilayers using the optical matrix method in order to test the dynamical theory of diffraction. The theory is generally valid for values of the bilayer thickness d up to about 100 A. For somewhat larger values of d, where the theory begins to break down, the initial discrepancy is in the phase of the oscillations in the wings of the peaks. For very large values of d, where the first-order Bragg peak approaches the edge of the mirror reflection, two general types of multilayers can be distinguished. In the first (typified in the present work by Ni/Ti), there is a large (30% or more) reduction in the actual value of the critical wave vector for total reflection while, in the second (typified here by Fe/Ge), there is very little reduction (3 % or so). The origin of these two very different types of behavior is explained. It is also shown that, within the dynamical theory of diffraction, the change in the position of the center of the Dar...

  19. Towards friction control using laser-induced periodic surface structures

    NARCIS (Netherlands)

    Eichstädt, J.; Römer, Gerardus Richardus, Bernardus, Engelina; Huis in 't Veld, Bert; Schmidt, M.; Zaeh, M.

    2011-01-01

    This paper aims at contributing to the study of laser-induced periodic surface structures (LIPSS) and the description of their tribological properties in order to facilitate the knowledge for contact mechanical applications. To obtain laser parameters for LIPSS formation, we propose to execute two

  20. Towards Periodicity Based Anomaly Detection in SCADA Networks

    NARCIS (Netherlands)

    Barbosa, R.R.R.; Sadre, R.; Pras, Aiko

    Supervisory Control and Data Acquisition (SCADA) networks are commonly deployed to aid the operation of large industrial facilities. The polling mechanism used to retrieve data from field devices causes the data transmission to be highly periodic. In this paper, we propose an approach that exploits

  1. Problems of Software Detection of Periodic Features in a Time ...

    African Journals Online (AJOL)

    Problems arise when attempts are made to extract automatically, visually obvious periodic features indicative of defects in a vibration time series for diagnosis using computers. Such problems may be interpretational in nature arising either from insufficient knowledge of the mechanism, or the convolution of the source signal ...

  2. Automotive Mechanics.

    Science.gov (United States)

    Linder, Ralph C.; And Others

    This curriculum guide, which was validated by vocational teachers and mechanics in the field, describes the competencies needed by entry-level automotive mechanics. This guide lists 15 competencies; for each competency, various tasks with their performance objective, student learning experiences, suggested instructional techniques, instructional…

  3. Quantum mechanics

    CERN Document Server

    Rae, Alastair I M

    2016-01-01

    A Thorough Update of One of the Most Highly Regarded Textbooks on Quantum Mechanics Continuing to offer an exceptionally clear, up-to-date treatment of the subject, Quantum Mechanics, Sixth Edition explains the concepts of quantum mechanics for undergraduate students in physics and related disciplines and provides the foundation necessary for other specialized courses. This sixth edition builds on its highly praised predecessors to make the text even more accessible to a wider audience. It is now divided into five parts that separately cover broad topics suitable for any general course on quantum mechanics. New to the Sixth Edition * Three chapters that review prerequisite physics and mathematics, laying out the notation, formalism, and physical basis necessary for the rest of the book * Short descriptions of numerous applications relevant to the physics discussed, giving students a brief look at what quantum mechanics has made possible industrially and scientifically * Additional end-of-chapter problems with...

  4. Respiratory mechanics

    CERN Document Server

    Wilson, Theodore A

    2016-01-01

    This book thoroughly covers each subfield of respiratory mechanics: pulmonary mechanics, the respiratory pump, and flow. It presents the current understanding of the field and serves as a guide to the scientific literature from the golden age of respiratory mechanics, 1960 - 2010. Specific topics covered include the contributions of surface tension and tissue forces to lung recoil, the gravitational deformation of the lung, and the interdependence forces that act on pulmonary airways and blood vessels. The geometry and kinematics of the ribs is also covered in detail, as well as the respiratory action of the external and internal intercostal muscles, the mechanics of the diaphragm, and the quantitative compartmental models of the chest wall is also described. Additionally, flow in the airways is covered thoroughly, including the wave-speed and viscous expiratory flow-limiting mechanisms; convection, diffusion and the stationary front; and the distribution of ventilation. This is an ideal book for respiratory ...

  5. College mechanics

    CERN Document Server

    Şengül, Caner

    2016-01-01

    College Mechanics QueBank has been designed to be different, enthusiastic, interesting and helpful to you. Therefore, it is not just a test bank about mechanics but also it is like a compass in order to find your way in mechanics Each chapter in this book is put in an order to follow a hierarchy of the mechanics topics; from vectors to simple harmonic motion. Throughout the book there are many multiple choice and long answer questions for you to solve. They have been created for YGS, LYS, SAT, IB or other standardized exams in the world because mechanics has no boundaries and so Physics has no country. Learn the main principle of each chapter and explore the daily life applications. Then you can start to solve the questions by planning a problem solving method carefully. Finally, enjoy solving the questions and discover the meachanics of the universe once more.

  6. Fracture Mechanics

    CERN Document Server

    Zehnder, Alan T

    2012-01-01

    Fracture mechanics is a vast and growing field. This book develops the basic elements needed for both fracture research and engineering practice. The emphasis is on continuum mechanics models for energy flows and crack-tip stress- and deformation fields in elastic and elastic-plastic materials. In addition to a brief discussion of computational fracture methods, the text includes practical sections on fracture criteria, fracture toughness testing, and methods for measuring stress intensity factors and energy release rates. Class-tested at Cornell, this book is designed for students, researchers and practitioners interested in understanding and contributing to a diverse and vital field of knowledge. Alan Zehnder joined the faculty at Cornell University in 1988. Since then he has served in a number of leadership roles including Chair of the Department of Theoretical and Applied Mechanics, and Director of the Sibley School of Mechanical and Aerospace Engineering.  He teaches applied mechanics and his research t...

  7. Sensitive periods in affective development: nonlinear maturation of fear learning.

    Science.gov (United States)

    Hartley, Catherine A; Lee, Francis S

    2015-01-01

    At specific maturational stages, neural circuits enter sensitive periods of heightened plasticity, during which the development of both brain and behavior are highly receptive to particular experiential information. A relatively advanced understanding of the regulatory mechanisms governing the initiation, closure, and reinstatement of sensitive period plasticity has emerged from extensive research examining the development of the visual system. In this article, we discuss a large body of work characterizing the pronounced nonlinear changes in fear learning and extinction that occur from childhood through adulthood, and their underlying neural substrates. We draw upon the model of sensitive period regulation within the visual system, and present burgeoning evidence suggesting that parallel mechanisms may regulate the qualitative changes in fear learning across development.

  8. Periodic solutions of asymptotically linear Hamiltonian systems without twist conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Rong [Coll. of Mathematics and Physics, Nanjing Univ. of Information Science and Tech., Nanjing (China); Dept. of Mathematics, Southeast Univ., Nanjing (China); Zhang Dongfeng [Dept. of Mathematics, Southeast Univ., Nanjing (China)

    2010-05-15

    In dynamical system theory, especially in many fields of applications from mechanics, Hamiltonian systems play an important role, since many related equations in mechanics can be written in an Hamiltonian form. In this paper, we study the existence of periodic solutions for a class of Hamiltonian systems. By applying the Galerkin approximation method together with a result of critical point theory, we establish the existence of periodic solutions of asymptotically linear Hamiltonian systems without twist conditions. Twist conditions play crucial roles in the study of periodic solutions for asymptotically linear Hamiltonian systems. The lack of twist conditions brings some difficulty to the study. To the authors' knowledge, very little is known about the case, where twist conditions do not hold. (orig.)

  9. Self-organizing periodicity in development: organ positioning in plants.

    Science.gov (United States)

    Bhatia, Neha; Heisler, Marcus G

    2018-02-08

    Periodic patterns during development often occur spontaneously through a process of self-organization. While reaction-diffusion mechanisms are often invoked, other types of mechanisms that involve cell-cell interactions and mechanical buckling have also been identified. Phyllotaxis, or the positioning of plant organs, has emerged as an excellent model system to study the self-organization of periodic patterns. At the macro scale, the regular spacing of organs on the growing plant shoot gives rise to the typical spiral and whorled arrangements of plant organs found in nature. In turn, this spacing relies on complex patterns of cell polarity that involve feedback between a signaling molecule - the plant hormone auxin - and its polar, cell-to-cell transport. Here, we review recent progress in understanding phyllotaxis and plant cell polarity and highlight the development of new tools that can help address the remaining gaps in our understanding. © 2018. Published by The Company of Biologists Ltd.

  10. Statistical mechanics of anyons

    International Nuclear Information System (INIS)

    Arovas, D.P.

    1985-01-01

    We study the statistical mechanics of a two-dimensional gas of free anyons - particles which interpolate between Bose-Einstein and Fermi-Dirac character. Thermodynamic quantities are discussed in the low-density regime. In particular, the second virial coefficient is evaluated by two different methods and is found to exhibit a simple, periodic, but nonanalytic behavior as a function of the statistics determining parameter. (orig.)

  11. Crystallography beyond periodic Crystal perfection

    International Nuclear Information System (INIS)

    Estevez-Rams, E.

    2008-01-01

    Full text: The discovery of the quasi-crystals [D. Schechtman et. Al., Phys.] Rev. Lett. [53, 1951-1953 (1984)] made very narrow definition of the crystalline state based on the periodicity of a local arrangement of atoms. Since the definition of this State has been a matter of much controversy [G.R. Desiraju, Nature 423, 485 (2003); S. van Smaalen, IUCR Aperiodic Commission Reports. August 7, 2002; International Union of Crystallography. Report of the Executive Committee for 1991; ACTA Cryst. A48, 922-946 (1992)]. We will make a presentation of the current time of the crystallography in this regard from the conceptual point of view. We show the use of the formalism of algorithmic complexity or Kolmogorov [M. Li and P. Vitanyi, An Introduction to Kolmogorov Complexity and Its Applications (Springer Verlag, Heidelberg, 1993), W.H. Zurek, Phys.] Rev. 40, 4731 (1989); Nature 341, 119-124 (1989)] provides a different perspective on the nature of the Crystallographic order. Infinite crystals can be considered solid with zero algorithmic complexities by atom. Show statistical analysis of inorganic compounds [J.L.C. Daams et al., Atlas of Crystal Structure Types for Intermetallic Phases (ASM International, Ohio, 1991), Fachinformationszentrum/NIST Inorganic Crystal Structure Database, Karlsruhe (2003) icsd.fkf.mpg.de] demonstrating that the minimization of complexity is a trend in the crystalline arrangement. We will then compare the degree of disorder of some typical solids according to their algorithmic complexity. Finally, space diffraction will be studied from this same perspective and will be discussed that zero algorithmic complexities by point in space of diffraction does not necessarily imply the same thing for the Atomic arrangement. The discrete portion of the diffraction pattern is a fingerprint of the underlying order but not the actual existence of long-range order. Experimental results will be showcased [E. Estévez-Rams et al., Physical Review B, 63 (2001

  12. Quantum mechanics

    CERN Document Server

    Powell, John L

    2015-01-01

    Suitable for advanced undergraduates, this thorough text focuses on the role of symmetry operations and the essentially algebraic structure of quantum-mechanical theory. Based on courses in quantum mechanics taught by the authors, the treatment provides numerous problems that require applications of theory and serve to supplement the textual material.Starting with a historical introduction to the origins of quantum theory, the book advances to discussions of the foundations of wave mechanics, wave packets and the uncertainty principle, and an examination of the Schrödinger equation that includ

  13. Quantum mechanics

    International Nuclear Information System (INIS)

    Rae, A.I.M.

    1981-01-01

    This book, based on a thirty lecture course given to students at the beginning of their second year, covers the quantum mechanics required by physics undergraduates. Early chapters deal with wave mechanics, including a discussion of the energy states of the hydrogen atom. These are followed by a more formal development of the theory, leading to a discussion of some advanced applications and an introduction to the conceptual problems associated with quantum measurement theory. Emphasis is placed on the fundamentals of quantum mechanics. Problems are included at the end of each chapter. (U.K.)

  14. Indexing mechanisms

    International Nuclear Information System (INIS)

    Wood, A.G.; Parker, G.E.; Berry, R.

    1976-01-01

    It is stated that the indexing mechanism described can be used in a nuclear reactor fuel element inspection rig. It comprises a tubular body adapted to house a canister containing a number of fuel elements located longtitudinally, and has two chucks spaced apart for displacing the fuel elements longitudinally in a stepwise manner, together with a plunger mechanism for displacing them successively into the chucks. A measuring unit is located between the chucks for measuring the diameter of the fuel elements at intervals about their circumferences, and a secondary indexing mechanism is provided for rotating the measuring unit in a stepwise manner. (U.K.)

  15. Robot Mechanisms

    CERN Document Server

    Lenarcic, Jadran; Stanišić, Michael M

    2013-01-01

    This book provides a comprehensive introduction to the area of robot mechanisms, primarily considering industrial manipulators and humanoid arms. The book is intended for both teaching and self-study. Emphasis is given to the fundamentals of kinematic analysis and the design of robot mechanisms. The coverage of topics is untypical. The focus is on robot kinematics. The book creates a balance between theoretical and practical aspects in the development and application of robot mechanisms, and includes the latest achievements and trends in robot science and technology.

  16. Rhythm generation through period concatenation in rat somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Mark A Kramer

    2008-09-01

    Full Text Available Rhythmic voltage oscillations resulting from the summed activity of neuronal populations occur in many nervous systems. Contemporary observations suggest that coexistent oscillations interact and, in time, may switch in dominance. We recently reported an example of these interactions recorded from in vitro preparations of rat somatosensory cortex. We found that following an initial interval of coexistent gamma ( approximately 25 ms period and beta2 ( approximately 40 ms period rhythms in the superficial and deep cortical layers, respectively, a transition to a synchronous beta1 ( approximately 65 ms period rhythm in all cortical layers occurred. We proposed that the switch to beta1 activity resulted from the novel mechanism of period concatenation of the faster rhythms: gamma period (25 ms+beta2 period (40 ms = beta1 period (65 ms. In this article, we investigate in greater detail the fundamental mechanisms of the beta1 rhythm. To do so we describe additional in vitro experiments that constrain a biologically realistic, yet simplified, computational model of the activity. We use the model to suggest that the dynamic building blocks (or motifs of the gamma and beta2 rhythms combine to produce a beta1 oscillation that exhibits cross-frequency interactions. Through the combined approach of in vitro experiments and mathematical modeling we isolate the specific components that promote or destroy each rhythm. We propose that mechanisms vital to establishing the beta1 oscillation include strengthened connections between a population of deep layer intrinsically bursting cells and a transition from antidromic to orthodromic spike generation in these cells. We conclude that neural activity in the superficial and deep cortical layers may temporally combine to generate a slower oscillation.

  17. Platelet function in the postprandial period

    Directory of Open Access Journals (Sweden)

    Sinzinger Helmut

    2012-09-01

    Full Text Available Abstract Background Postprandial hyperlipidemia and hyperglycemia have been related to cardiovascular events. Among different underlying mechanisms platelet activation seems to be responsible too. No comparable data between various tests in normo- vs. hyperlipidemics before and at different time intervals are available after a fat meal. We aimed to compare 9 of them within the same patients at several time points in postprandial hyperlipidemia. Results For some tests baseline values between the groups were significantly different (TXB2, platelet sensitivity, sedimentation and WU-test. However, hyperlipidemia revealed a variable influence on the tests examined. Some of the available tests apparently sensitive to show platelet activation reflect the increase in triglycerides (TG, such as the sedimentation index. ADP-induced platelet aggregatory activity in count adjusted washed isolated platelet samples during postprandial hyperlipidemia indicates mildly enhanced platelet activity, but does not seem to induce significant changes in aggregation. In patients with severe hypertriglyceridemia (> 400 mg/dl fasting changes in platelet function are more pronounced due to delayed decay and may last up to 16 hours paralleling TG reaching the prevalue. The overwhelming majority of platelet function tests do not significantly respond to postprandial hyperlipidemia. The correlation between the tests applied is poor. For standardization purpose, platelet aggregation tests, aimed to examine proaggregatory capacity in atherosclerosis, should only be performed at the same time of the day after a fasting period > 6 hours. The great variation in preanalytical work-up on comparison of various tests, large number of platelet tests available and their respective potential value are discussed. Conclusions At present, the suspicion that platelet function is significantly activated in the postprandial period cannot be supported by any of the tests used. The

  18. Fracture mechanics

    CERN Document Server

    Perez, Nestor

    2017-01-01

    The second edition of this textbook includes a refined presentation of concepts in each chapter, additional examples; new problems and sections, such as conformal mapping and mechanical behavior of wood; while retaining all the features of the original book. The material included in this book is based upon the development of analytical and numerical procedures pertinent to particular fields of linear elastic fracture mechanics (LEFM) and plastic fracture mechanics (PFM), including mixed-mode-loading interaction. The mathematical approach undertaken herein is coupled with a brief review of several fracture theories available in cited references, along with many color images and figures. Dynamic fracture mechanics is included through the field of fatigue and Charpy impact testing. Explains computational and engineering approaches for solving crack-related problems using straightforward mathematics that facilitate comprehension of the physical meaning of crack growth processes; Expands computational understandin...

  19. Analytical mechanics

    CERN Document Server

    Lemos, Nivaldo A

    2018-01-01

    Analytical mechanics is the foundation of many areas of theoretical physics including quantum theory and statistical mechanics, and has wide-ranging applications in engineering and celestial mechanics. This introduction to the basic principles and methods of analytical mechanics covers Lagrangian and Hamiltonian dynamics, rigid bodies, small oscillations, canonical transformations and Hamilton–Jacobi theory. This fully up-to-date textbook includes detailed mathematical appendices and addresses a number of advanced topics, some of them of a geometric or topological character. These include Bertrand's theorem, proof that action is least, spontaneous symmetry breakdown, constrained Hamiltonian systems, non-integrability criteria, KAM theory, classical field theory, Lyapunov functions, geometric phases and Poisson manifolds. Providing worked examples, end-of-chapter problems, and discussion of ongoing research in the field, it is suitable for advanced undergraduate students and graduate students studying analyt...

  20. Engineering mechanics

    CERN Document Server

    Gross, Dietmar; Schröder, Jörg; Wall, Wolfgang A; Rajapakse, Nimal

    Statics is the first volume of a three-volume textbook on Engineering Mechanics. The authors, using a time-honoured straightforward and flexible approach, present the basic concepts and principles of mechanics in the clearest and simplest form possible to advanced undergraduate engineering students of various disciplines and different educational backgrounds. An important objective of this book is to develop problem solving skills in a systematic manner. Another aim of this volume is to provide engineering students as well as practising engineers with a solid foundation to help them bridge the gap between undergraduate studies on the one hand and advanced courses on mechanics and/or practical engineering problems on the other. The book contains numerous examples, along with their complete solutions. Emphasis is placed upon student participation in problem solving. The contents of the book correspond to the topics normally covered in courses on basic engineering mechanics at universities and colleges. Now in i...

  1. Soil Mechanics

    OpenAIRE

    Verruijt, A.

    2010-01-01

    This book is the text for the introductory course of Soil Mechanics in the Department of Civil Engineering of the Delft University of Technology, as I have given from 1980 until my retirement in 2002. It contains an introduction into the major principles and methods of soil mechanics, such as the analysis of stresses, deformations, and stability. The most important methods of determining soil parameters, in the laboratory and in situ, are also described. Some basic principles of applied mecha...

  2. QUASI-PERIODICITIES AT YEAR-LIKE TIMESCALES IN BLAZARS

    Energy Technology Data Exchange (ETDEWEB)

    Sandrinelli, A.; Treves, A. [Università degli Studi dell’Insubria, Dipartimento di Scienza ed Alta Tecnologia, Via Valleggio 11, I-22100 Como (Italy); Covino, S. [INAF—Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Brera, Via Emilio Bianchi 46, I-23807 Merate (Italy); Dotti, M. [Università degli Studi di Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano (Italy)

    2016-03-15

    We searched for quasi-periodicities on year-like timescales in the light curves of six blazars in the optical—near-infrared bands and we made a comparison with the high energy emission. We obtained optical/NIR light curves from Rapid Eye Mounting photometry plus archival Small and Moderate Aperture Research Telescope System data and we accessed the Fermi light curves for the γ-ray data. The periodograms often show strong peaks in the optical and γ-ray bands, which in some cases may be inter-related. The significance of the revealed peaks is then discussed, taking into account that the noise is frequency dependent. Quasi-periodicities on a year-like timescale appear to occur often in blazars. No straightforward model describing these possible periodicities is yet available, but some plausible interpretations for the physical mechanisms causing periodic variabilities of these sources are examined.

  3. Climatology and forest decay - stresses caused by dry periods

    International Nuclear Information System (INIS)

    Havlik, D.

    1991-01-01

    In the discussion of forest decline in the Eighties, stresses due to dry weather is often named as a secondary cause. The concept of 'climatological dry periods' is introduced in this article and applied to records for the Basel and Aachen regions. The time distribution of dry periods of different length and different water deficiency (40 mm, 60 mm, 100 mm) is analyzed. In the case of the Basel data, the dry periods are related to the 'forest damage caused by draught' recorded for the Basel region since 1930. The results support the theory that increasingly larger and more frequent dry periods with water shortage have contributed significantly to forest damage in the last 15 years. Apart from the 'dry stress' itself, also the enhanced production of photooxidants is a damaging mechanism. (orig.) [de

  4. Periodic precursors of nonlinear dynamical transitions

    International Nuclear Information System (INIS)

    Jiang Yu; Dong Shihai; Lozada-Cassou, M.

    2004-01-01

    We study the resonant response of a nonlinear system to external periodic perturbations. We show by numerical simulation that the periodic resonance curve may anticipate the dynamical instability of the unperturbed nonlinear periodic system, at parameter values far away from the bifurcation points. In the presence of noise, the buried intrinsic periodic dynamics can be picked out by analyzing the system's response to periodic modulation of appropriate intensity

  5. Leaching mechanisms

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Colombo, P.

    1984-01-01

    Sufficient data are lacking to provide a basis for adequately assessing the long term leaching behavior of solidified low level radioactive waste forms in their disposal environment. Although the release of radioactivity from a waste form to an aqueous environment is recognized to be due to one or more mechanisms such as diffusion, dissolution, corrosion or ion exchange, the leaching mechanisms and the factors which control the leaching behavior of waste forms are not fully understood. This study will determine the prevailing mechanisms for a variety of selected LLW solidification agents which are being considered for use by defense and commercial generators and which will cover the broadest possible number of mechanisms. The investigation will proceed by the postulation of mathematical models representative of the prevailing mechanism(s) and the use of statistically designed experiments to test the actual leaching behavior of laborattory samples against the postulated representations. Maximum use of existing leach data in the literature will be made by incorporating literature results into a computerized data base along with the experimental results generated in this task

  6. Preferred Hosts for Short-Period Exoplanets

    Science.gov (United States)

    Kohler, Susanna

    2015-12-01

    In an effort to learn more about how planets form around their host stars, a team of scientists has analyzed the population of Kepler-discovered exoplanet candidates, looking for trends in where theyre found.Planetary OccurrenceSince its launch in 2009, Kepler has found thousands of candidate exoplanets around a variety of star types. Especially intriguing is the large population of super-Earths and mini-Neptunes planets with masses between that of Earth and Neptune that have short orbital periods. How did they come to exist so close to their host star? Did they form in situ, or migrate inwards, or some combination of both processes?To constrain these formation mechanisms, a team of scientists led by Gijs Mulders (University of Arizona and NASAs NExSS coalition) analyzed the population of Kepler planet candidates that have orbital periods between 2 and 50 days.Mulders and collaborators used statistical reconstructions to find the average number of planets, within this orbital range, around each star in the Kepler field. They then determined how this planet occurrence rate changed for different spectral types and therefore the masses of the host stars: do low-mass M-dwarf stars host more or fewer planets than higher-mass, main-sequence F, G, or K stars?Challenging ModelsAuthors estimates for the occurrence rate for short-period planets of different radii around M-dwarfs (purple) and around F, G, and K-type stars (blue). [Mulders et al. 2015]The team found that M dwarfs, compared to F, G, or K stars, host about half as many large planets with orbital periods of P 50 days. But, surprisingly, they host significantly more small planets, racking up an average of 3.5 times the number of planets in the size range of 12.8 Earth-radii.Could it be that M dwarfs have a lower total mass of planets, but that mass is distributed into more, smaller planets? Apparently not: the authors show that the mass of heavy elements trapped in short-orbital-period planets is higher for M

  7. Approaches and Methods of Periodization in Literary History

    Directory of Open Access Journals (Sweden)

    Naser Gholi Sarli

    2013-10-01

    Full Text Available Abstract One of the most fundamental acts of historiography is to classify historical information in diachronic axis. The method of this classification or periodization shows the theoretical approach of the historian and determines the structure and the form of his history. Because of multiple criteria of analysis and various literary genres, periodization in literary history is more complicated than that of general history. We can distinguish two approaches in periodization of literary history, although these can be used together: extrinsic or social-cultural approach (based on criteria extrinsic to literature and intrinsic or formalist approach (based on criteria intrinsic to literature. Then periodization in literary history can be formulated in different methods and may be based upon various criteria: chronological such as century, decade and year organic patterns of evolution great poets and writers literary emblems and evaluations of every period events, concepts and periods of general or political history analogy of literary history and history of ideas or history of arts approaches and styles of language dominant literary norms. These methods actually are used together and everyone has adequacy in special kind of literary history. In periodization of Persian contemporary literature, some methods and models current in periodization of poetry have been applied identically to periodization of prose. Periodization based upon century, decade and year is the simplest and most mechanical method but sometimes certain centuries in some countries have symbolic and stylistic meaning, and decades were used often for subdivisions of literary history, especially nowadays with fast rhythm of literary change. Periodization according to organic patterns of evolution equates the changes of literary history with the life phases of an organism, and offers an account of birth, mature and death (and sometimes re-birth of literary genres, but this method have

  8. Approaches and Methods of Periodization in Literary History

    Directory of Open Access Journals (Sweden)

    Dr. N. Gh. Sarli

    Full Text Available One of the most fundamental acts of historiography is to classify historical information in diachronic axis. The method of this classification or periodization shows the theoretical approach of the historian and determines the structure and the form of his history. Because of multiple criteria of analysis and various literary genres, periodization in literary history is more complicated than that of general history. We can distinguish two approaches in periodization of literary history, although these can be used together: extrinsic or social-cultural approach (based on criteria extrinsic to literature and intrinsic or formalist approach (based on criteria intrinsic to literature. Then periodization in literary history can be formulated in different methods and may be based upon various criteria: chronological such as century, decade and year; organic patterns of evolution; great poets and writers; literary emblems and evaluations of every period; events, concepts and periods of general or political history; analogy of literary history and history of ideas or history of arts; approaches and styles of language; dominant literary norms. These methods actually are used together and everyone has adequacy in special kind of literary history. In periodization of Persian contemporary literature, some methods and models current in periodization of poetry have been applied identically to periodization of prose. Periodization based upon century, decade and year is the simplest and most mechanical method but sometimes certain centuries in some countries have symbolic and stylistic meaning, and decades were used often for subdivisions of literary history, especially nowadays with fast rhythm of literary change.Periodization according to organic patterns of evolution equates the changes of literary history with the life phases of an organism, and offers an account of birth, mature and death (and sometimes re-birth of literary genres, but this method have

  9. Approaches and Methods of Periodization in Literary History

    Directory of Open Access Journals (Sweden)

    Naser Gholi Sarli

    2013-11-01

    Full Text Available Abstract One of the most fundamental acts of historiography is to classify historical information in diachronic axis. The method of this classification or periodization shows the theoretical approach of the historian and determines the structure and the form of his history. Because of multiple criteria of analysis and various literary genres, periodization in literary history is more complicated than that of general history. We can distinguish two approaches in periodization of literary history, although these can be used together: extrinsic or social-cultural approach (based on criteria extrinsic to literature and intrinsic or formalist approach (based on criteria intrinsic to literature. Then periodization in literary history can be formulated in different methods and may be based upon various criteria: chronological such as century, decade and year organic patterns of evolution great poets and writers literary emblems and evaluations of every period events, concepts and periods of general or political history analogy of literary history and history of ideas or history of arts approaches and styles of language dominant literary norms. These methods actually are used together and everyone has adequacy in special kind of literary history. In periodization of Persian contemporary literature, some methods and models current in periodization of poetry have been applied identically to periodization of prose. Periodization based upon century, decade and year is the simplest and most mechanical method but sometimes certain centuries in some countries have symbolic and stylistic meaning, and decades were used often for subdivisions of literary history, especially nowadays with fast rhythm of literary change. Periodization according to organic patterns of evolution equates the changes of literary history with the life phases of an organism, and offers an account of birth, mature and death (and sometimes re-birth of literary genres, but this method have

  10. AFSC/NMML/CCEP: California Current Ecosystem Program and Cascadia Research Collective: Aerial and small boat line transect data in waters of OR/WA/BC from 1989, 1990, 1991, 1996, 1997, 2002, and 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) a division of NOAA's Alaska Fisheries Science Center (Seattle, WA) and Cascadia Research Collective (Olympia, WA)...

  11. Coeur d'Alene Tribe Fish and Wildlife Program Habitat Protection Plan; Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation, 1997-2002 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Angelo; Roberts, Frank; Peters, Ronald

    2002-06-01

    Throughout the last century, the cumulative effects of anthropogenic disturbances have caused drastic watershed level landscape changes throughout the Reservation and surrounding areas (Coeur d'Alene Tribe 1998). Changes include stream channelization, wetland draining, forest and palouse prairie conversion for agricultural use, high road density, elimination of old growth timber stands, and denuding riparian communities. The significance of these changes is manifested in the degradation of habitats supporting native flora and fauna. Consequently, populations of native fish, wildlife, and plants, which the Tribe relies on as subsistence resources, have declined or in some instances been extirpated (Apperson et al. 1988; Coeur d'Alene Tribe 1998; Lillengreen et al. 1996; Lillengreen et al. 1993; Gerry Green Coeur d'Alene Tribe wildlife Biologist, personal communication 2002). For example, bull trout (Salvelinus confluentus) are not present at detectable levels in Reservation tributaries, westslope cutthroat trout (Oncorhynchus clarki lewisi) are not present in numbers commensurate with maintaining harvestable fisheries (Lillengreen et al. 1993, 1996), and the Sharp-tailed grouse (Tympanuchus phasianellus) are not present at detectable levels on the Reservation (Gerry Green, Coeur d'Alene Tribe wildlife biologist, personal communication). The Coeur d'Alene Tribe added Fisheries and Wildlife Programs to their Natural Resources Department to address these losses and protect important cultural, and subsistence resources for future generations. The Tribal Council adopted by Resolution 89(94), the following mission statement for the Fisheries Program: 'restore, protect, expand and re-establish fish populations to sustainable levels to provide harvest opportunities'. This mission statement, focused on fisheries restoration and rehabilitation, is a response to native fish population declines throughout the Tribe's aboriginal territory, including the Coeur d'Alene Indian Reservation (Coeur d'Alene Tribe 1998). Implicit in this statement is a commitment to provide native subsistence resources in the present and near future as well as the long-term by employing all the mitigation and conservation measures available to them. The development of this Habitat Protection Plan is intended to provide additional planning level guidance as the implementation of conservation measures moves forward. The purpose of this plan is to develop a systematic approach to habitat restoration that will ultimately lead to self-perpetuating, harvestable populations of native fish, wildlife and botanical species. Specifically, it is our intention to apply the principles and analyses presented in this plan to prioritize future restoration efforts that receive funding under the Northwest Power Planning Council's Resident Fish and Wildlife Mitigation Programs. Using an ecosystem restoration approach based on landscape ecology concepts (Primack 1993), the basic premise of the plan is to (1) protect functioning habitat conditions and (2) restore degraded habitat conditions. This plan focuses on habitat conditions at the watershed scale (macrohabitat) rather than on the needs of single species and/or species guilds. By focusing restoration efforts at a macrohabitat level, restoration efforts target all native species inhabiting that area. This approach marks a paradigm shift that emphasizes ecological based restoration rather than species-specific restoration. Traditionally, fish managers and wildlife managers have approached restoration independently, often dedicating resources to a single species by focusing on specific habitat types on a small spatial scale (microhabitat) (Robinson and Bolen 1989, Marcot et al. 2002). This management technique has done little to curb declines despite large budgets (Pianka 1994). Restoration on a landscape level has shown promising results (Holling 1992) and many riparian and wetland restoration projects throughout the northwest have inadvertently improved habitats for non-targeted species. Landscape level restoration addresses the overall habitat condition of the regional area (macrohabitat), restoring the native species composition, density, and diversity by restoring the native ecosystem function. In the context of the development and implementation of this Habitat Protection Plan, it is important to understand that this is primarily a conservation tool, and is not intended to displace efforts that mitigate for lost resources. This plan is intended to primarily address long-term conservation needs and may not accommodate immediate short-term needs that address lost resources. Therefore, areas selected to address short-term mitigation needs may not be located in the high priority areas identified in this Plan. It needs to be clear that these projects and areas are no less important than those identified in this Plan.

  12. Temperature, salinity, nutrients, oxygen and other data profiles from CTD and bottle casts from NOAA/NMFS cruises of NOAA Ship Townsend Cromwell in the central north Pacific, 1997-2002 (NODC Accession 0100295)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains measurements from CTD hydrocast stations from seven cruises of NOAA Ship Townsend Cromwell in the central north Pacific from 1997 to 2002...

  13. Comparative Survival Study (CSS) of Hatchery PIT-tagged Spring/Summer Chinook; Migration Years 1997-2002 Mark/Recapture Activities and Bootstrap Analysis, 2003-2004 Biennial Report.

    Energy Technology Data Exchange (ETDEWEB)

    Berggren, Thomas J.; Franzoni, Henry; Basham, Larry R. (Columbia Basin Fish and Wildlife Authority, Fish Passage Center, Portland, OR)

    2003-11-01

    The Comparative Survival Study (CSS) was initiated in 1996 as a multi-year program of the fishery agencies and tribes to estimate survival rates over different life stages for spring and summer Chinook (hereafter, Chinook) produced in major hatcheries in the Snake River basin and from selected hatcheries in the lower Columbia River. Much of the information evaluated in the CSS is derived from fish tagged with Passive Integrated Transponder (PIT) tags. A comparison of survival rates of Chinook marked in two different regions (which differ in the number of dams Chinook have to migrate through) provides insight into the effects of the Snake/Columbia hydroelectric system (hydrosystem). The CSS also compares the smolt-to-adult survival rates (SARs) for Snake River Chinook that were transported versus those that migrated in-river to below Bonneville Dam. Additional comparisons can be made within in-river experiences as well as comparison between the different collector projects from which smolts are transported. CSS also compares survival rates for wild Snake River spring and summer Chinook. These comparisons generate information regarding the relative effects of the current management actions used to recover this listed species. Scientists and managers have recently emphasized the importance of delayed hydrosystem mortality to long-term management decisions. Delayed hydrosystem mortality may be related to the smolts experience in the Federal Columbia River Power System, and could occur for both smolts that migrate in-river and smolts that are transported. The CSS PIT tag information on in-river survival rates and smolt-to-adult survival rates (SARs) of transported and in-river fish are relevant to estimation of ''D'', which partially describes delayed hydrosystem mortality. The parameter D is the differential survival rate of transported fish relative to fish that migrate in-river, as measured from below Bonneville Dam to adults returning to Lower Granite Dam. When D = 1, there is no difference in survival rate after hydrosystem passage. When D < 1, then transported smolts die at a greater rate after release below Bonneville Dam than smolts that have migrated in-river to below Bonneville Dam Major objectives of the CSS include: (1) development of a long-term index of transport SAR to in-river SAR for Snake River hatchery and wild spring and summer Chinook smolts measured at Lower Granite Dam; (2) develop a long-term index of survival rates from release of smolts at Snake River hatcheries to return of adults to the hatcheries; (3) compute and compare the overall SARs for selected upriver and downriver spring and summer Chinook hatchery and wild stocks; and (4) begin a time series of SARs for use in hypothesis testing and in the regional long-term monitoring and evaluation program. Primary CSS focus in this report is for wild and hatchery spring/summer Chinook that outmigrated in 1997 to 2002 and their respective adult returns through 2004.

  14. The "sticking period" in a maximum bench press.

    Science.gov (United States)

    van den Tillaar, Roland; Ettema, Gertjan

    2010-03-01

    The purpose of this study was to examine muscle activity and three-dimensional kinematics in the ascending phase of a successful one-repetition maximum attempt in bench press for 12 recreational weight-training athletes, with special attention to the sticking period. The sticking period was defined as the first period of deceleration of the upward movement (i.e. from the highest barbell velocity until the first local lowest barbell velocity). All participants showed a sticking period during the upward movement that started about 0.2 s after the initial upward movement, and lasted about 0.9 s. Electromyography revealed that the muscle activity of the prime movers changed significantly from the pre-sticking to the sticking and post-sticking periods. A possible mechanism for the existence of the sticking period is the diminishing potentiation of the contractile elements during the upward movement together with the limited activity of the pectoral and deltoid muscles during this period.

  15. Complex trajectories in a classical periodic potential

    International Nuclear Information System (INIS)

    Anderson, Alexander G; Bender, Carl M

    2012-01-01

    This paper examines the complex trajectories of a classical particle in the potential V(x) = −cos (x). Almost all the trajectories describe a particle that hops from one well to another in an erratic fashion. However, it is shown analytically that there are two special classes of trajectories x(t) determined only by the energy of the particle and not by the initial position of the particle. The first class consists of periodic trajectories; that is, trajectories that return to their initial position x(0) after some real time T. The second class consists of trajectories for which there exists a real time T such that x(t + T) = x(t) ± 2π. These two classes of classical trajectories are analogous to valence and conduction bands in quantum mechanics, where the quantum particle either remains localized or else tunnels resonantly (conducts) through a crystal lattice. These two special types of trajectories are associated with sets of energies of measure 0. For other energies, it is shown that for long times the average velocity of the particle becomes a fractal-like function of energy. (paper)

  16. Complex trajectories in a classical periodic potential

    Science.gov (United States)

    Anderson, Alexander G.; Bender, Carl M.

    2012-11-01

    This paper examines the complex trajectories of a classical particle in the potential V(x) = -cos (x). Almost all the trajectories describe a particle that hops from one well to another in an erratic fashion. However, it is shown analytically that there are two special classes of trajectories x(t) determined only by the energy of the particle and not by the initial position of the particle. The first class consists of periodic trajectories; that is, trajectories that return to their initial position x(0) after some real time T. The second class consists of trajectories for which there exists a real time T such that x(t + T) = x(t) ± 2π. These two classes of classical trajectories are analogous to valence and conduction bands in quantum mechanics, where the quantum particle either remains localized or else tunnels resonantly (conducts) through a crystal lattice. These two special types of trajectories are associated with sets of energies of measure 0. For other energies, it is shown that for long times the average velocity of the particle becomes a fractal-like function of energy.

  17. Periodic Poisson Solver for Particle Tracking

    International Nuclear Information System (INIS)

    Dohlus, M.; Henning, C.

    2015-05-01

    A method is described to solve the Poisson problem for a three dimensional source distribution that is periodic into one direction. Perpendicular to the direction of periodicity a free space (or open) boundary is realized. In beam physics, this approach allows to calculate the space charge field of a continualized charged particle distribution with periodic pattern. The method is based on a particle mesh approach with equidistant grid and fast convolution with a Green's function. The periodic approach uses only one period of the source distribution, but a periodic extension of the Green's function. The approach is numerically efficient and allows the investigation of periodic- and pseudo-periodic structures with period lengths that are small compared to the source dimensions, for instance of laser modulated beams or of the evolution of micro bunch structures. Applications for laser modulated beams are given.

  18. Unstable periodic orbits and chaotic economic growth

    International Nuclear Information System (INIS)

    Ishiyama, K.; Saiki, Y.

    2005-01-01

    We numerically find many unstable periodic solutions embedded in a chaotic attractor in a macroeconomic growth cycle model of two countries with different fiscal policies, and we focus on a special type of the unstable periodic solutions. It is confirmed that chaotic behavior represented by the model is qualitatively and quantitatively related to the unstable periodic solutions. We point out that the structure of a chaotic solution is dissolved into a class of finite unstable periodic solutions picked out among a large number of periodic solutions. In this context it is essential for the unstable periodic solutions to be embedded in the chaotic attractor

  19. Quantum mechanics

    CERN Document Server

    Fitzpatrick, Richard

    2015-01-01

    Quantum mechanics was developed during the first few decades of the twentieth century via a series of inspired guesses made by various physicists, including Planck, Einstein, Bohr, Schroedinger, Heisenberg, Pauli, and Dirac. All these scientists were trying to construct a self-consistent theory of microscopic dynamics that was compatible with experimental observations. The purpose of this book is to present quantum mechanics in a clear, concise, and systematic fashion, starting from the fundamental postulates, and developing the theory in as logical manner as possible. Topics covered in the book include the fundamental postulates of quantum mechanics, angular momentum, time-dependent and time-dependent perturbation theory, scattering theory, identical particles, and relativistic electron theory.

  20. Analytical mechanics

    CERN Document Server

    Helrich, Carl S

    2017-01-01

    This advanced undergraduate textbook begins with the Lagrangian formulation of Analytical Mechanics and then passes directly to the Hamiltonian formulation and the canonical equations, with constraints incorporated through Lagrange multipliers. Hamilton's Principle and the canonical equations remain the basis of the remainder of the text. Topics considered for applications include small oscillations, motion in electric and magnetic fields, and rigid body dynamics. The Hamilton-Jacobi approach is developed with special attention to the canonical transformation in order to provide a smooth and logical transition into the study of complex and chaotic systems. Finally the text has a careful treatment of relativistic mechanics and the requirement of Lorentz invariance. The text is enriched with an outline of the history of mechanics, which particularly outlines the importance of the work of Euler, Lagrange, Hamilton and Jacobi. Numerous exercises with solutions support the exceptionally clear and concise treatment...

  1. Quantum mechanics

    CERN Document Server

    Ghosh, P K

    2014-01-01

    Quantum mechanics, designed for advanced undergraduate and graduate students of physics, mathematics and chemistry, provides a concise yet self-contained introduction to the formal framework of quantum mechanics, its application to physical problems and the interpretation of the theory. Starting with a review of some of the necessary mathematics, the basic concepts are carefully developed in the text. After building a general formalism, detailed treatment of the standard material - the harmonic oscillator, the hydrogen atom, angular momentum theory, symmetry transformations, approximation methods, identical particle and many-particle systems, and scattering theory - is presented. The concluding chapter discusses the interpretation of quantum mechanics. Some of the important topics discussed in the book are the rigged Hilbert space, deformation quantization, path integrals, coherent states, geometric phases, decoherene, etc. This book is characterized by clarity and coherence of presentation.

  2. Wave Mechanics or Wave Statistical Mechanics

    International Nuclear Information System (INIS)

    Qian Shangwu; Xu Laizi

    2007-01-01

    By comparison between equations of motion of geometrical optics and that of classical statistical mechanics, this paper finds that there should be an analogy between geometrical optics and classical statistical mechanics instead of geometrical mechanics and classical mechanics. Furthermore, by comparison between the classical limit of quantum mechanics and classical statistical mechanics, it finds that classical limit of quantum mechanics is classical statistical mechanics not classical mechanics, hence it demonstrates that quantum mechanics is a natural generalization of classical statistical mechanics instead of classical mechanics. Thence quantum mechanics in its true appearance is a wave statistical mechanics instead of a wave mechanics.

  3. Mechanical seals

    CERN Document Server

    Mayer, E

    1977-01-01

    Mechanical Seals, Third Edition is a source of practical information on the design and use of mechanical seals. Topics range from design fundamentals and test rigs to leakage, wear, friction and power, reliability, and special designs. This text is comprised of nine chapters; the first of which gives a general overview of seals, including various types of seals and their applications. Attention then turns to the fundamentals of seal design, with emphasis on six requirements that must be considered: sealing effectiveness, length of life, reliability, power consumption, space requirements, and c

  4. Statistical mechanics

    CERN Document Server

    Davidson, Norman

    2003-01-01

    Clear and readable, this fine text assists students in achieving a grasp of the techniques and limitations of statistical mechanics. The treatment follows a logical progression from elementary to advanced theories, with careful attention to detail and mathematical development, and is sufficiently rigorous for introductory or intermediate graduate courses.Beginning with a study of the statistical mechanics of ideal gases and other systems of non-interacting particles, the text develops the theory in detail and applies it to the study of chemical equilibrium and the calculation of the thermody

  5. PERIODIC AND APERIODIC VARIABILITY IN THE MOLECULAR CLOUD ρ OPHIUCHUS

    International Nuclear Information System (INIS)

    Parks, J. Robert; Plavchan, Peter; Gee, Alan H.; White, Russel J.

    2014-01-01

    Presented are the results of a near-IR photometric survey of 1678 stars in the direction of the ρ Ophiuchus (ρ Oph) star forming region using data from the 2MASS Calibration Database. For each target in this sample, up to 1584 individual J-, H-, and K s -band photometric measurements with a cadence of ∼1 day are obtained over three observing seasons spanning ∼2.5 yr; it is the most intensive survey of stars in this region to date. This survey identifies 101 variable stars with ΔK s -band amplitudes from 0.044 to 2.31 mag and Δ(J – K s ) color amplitudes ranging from 0.053 to 1.47 mag. Of the 72 young ρ Oph star cluster members included in this survey, 79% are variable; in addition, 22 variable stars are identified as candidate members. Based on the temporal behavior of the K s time-series, the variability is distinguished as either periodic, long time-scale or irregular. This temporal behavior coupled with the behavior of stellar colors is used to assign a dominant variability mechanism. A new period-searching algorithm finds periodic signals in 32 variable stars with periods between 0.49 to 92 days. The chief mechanism driving the periodic variability for 18 stars is rotational modulation of cool starspots while 3 periodically vary due to accretion-induced hot spots. The time-series for six variable stars contains discrete periodic ''eclipse-like'' features with periods ranging from 3 to 8 days. These features may be asymmetries in the circumstellar disk, potentially sustained or driven by a proto-planet at or near the co-rotation radius. Aperiodic, long time-scale variations in stellar flux are identified in the time-series for 31 variable stars with time-scales ranging from 64 to 790 days. The chief mechanism driving long time-scale variability is variable extinction or mass accretion rates. The majority of the variable stars (40) exhibit sporadic, aperiodic variability over no discernable time-scale. No chief variability mechanism

  6. PERIODIC AND APERIODIC VARIABILITY IN THE MOLECULAR CLOUD ρ OPHIUCHUS

    Energy Technology Data Exchange (ETDEWEB)

    Parks, J. Robert; Plavchan, Peter; Gee, Alan H. [Infrared Processing and Analysis Center, California Institute of Technology, Mail Code 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); White, Russel J., E-mail: parksj@chara.gsu.edu [Georgia State University, Department of Physics and Astronomy, 25 Park Place, Room 605, Atlanta, GA 30303 (United States)

    2014-03-01

    Presented are the results of a near-IR photometric survey of 1678 stars in the direction of the ρ Ophiuchus (ρ Oph) star forming region using data from the 2MASS Calibration Database. For each target in this sample, up to 1584 individual J-, H-, and K{sub s} -band photometric measurements with a cadence of ∼1 day are obtained over three observing seasons spanning ∼2.5 yr; it is the most intensive survey of stars in this region to date. This survey identifies 101 variable stars with ΔK{sub s} -band amplitudes from 0.044 to 2.31 mag and Δ(J – K{sub s} ) color amplitudes ranging from 0.053 to 1.47 mag. Of the 72 young ρ Oph star cluster members included in this survey, 79% are variable; in addition, 22 variable stars are identified as candidate members. Based on the temporal behavior of the K{sub s} time-series, the variability is distinguished as either periodic, long time-scale or irregular. This temporal behavior coupled with the behavior of stellar colors is used to assign a dominant variability mechanism. A new period-searching algorithm finds periodic signals in 32 variable stars with periods between 0.49 to 92 days. The chief mechanism driving the periodic variability for 18 stars is rotational modulation of cool starspots while 3 periodically vary due to accretion-induced hot spots. The time-series for six variable stars contains discrete periodic ''eclipse-like'' features with periods ranging from 3 to 8 days. These features may be asymmetries in the circumstellar disk, potentially sustained or driven by a proto-planet at or near the co-rotation radius. Aperiodic, long time-scale variations in stellar flux are identified in the time-series for 31 variable stars with time-scales ranging from 64 to 790 days. The chief mechanism driving long time-scale variability is variable extinction or mass accretion rates. The majority of the variable stars (40) exhibit sporadic, aperiodic variability over no discernable time-scale. No chief

  7. Mechanisms and mechanics of porosity formation in ductile iron castings

    Directory of Open Access Journals (Sweden)

    M. Perzyk

    2007-12-01

    Full Text Available Shrinkage defects in ductile iron castings can be of two basic types: shrinkage cavities associated with the liquid contraction prior to the expansion period of the iron as well as the porosity, which may appear even if the liquid shrinkage is fully compensated. In the present paper two possible mechanisms of the porosity are presented and analyzed. The first one is the Karsay’s mechanism based on the secondary shrinkage concept. The second one is the mechanism acting during the expansion period of the iron, first suggested by Ohnaka and co-authors and essentially modified by the present authors. The mechanical interactions between casting and mould are determined for the both mechanisms. Their analysis leads to the conclusion, that porosity forms during expansion period of the melt. The direct cause is the negative pressure which appears in the central part of the casting due to the differences in expansion coefficients of the fast cooling surface layer and slow cooling inner region. Observations concerning feeding behavior of ductile iron castings, based on this mechanism, agree well with industrial practice. The secondary shrinkage is not only needless to induce the porosity, but the corresponding mechanism of its occurrence, proposed by Karsay, does not seem to be valid.

  8. Depression in pregnancy and postpartum period.

    Science.gov (United States)

    Sood, Mamta; Sood, A K

    2003-01-01

    This prospective study was carried out in a service hospital, with the aim to study the prevalence and incidence of depression in pregnancy and postpartum period. Eighty Four consecutive patients attending the antenatal outpatient in the Obstetrics & Gynaecology department in their last trimester of pregnancy were recruited for the study. They were assessed on Beck Depression Inventory thrice viz. during third trimester of pregnancy, within 3 days of delivery (early postpartum period) & within 4-8 weeks of delivery (late postpartum period).The prevalence of depression was 8.3%, 20% and 12.8% respectively at three ratings. The incidence was 16% and 10% in the early & late postpartum period respectively. Further analysis revealed that depression in pregnancy correlated significantly with depression in early postpartum period, but not with late postpartum period. Depression in early postpartum period correlated with depression in late postpartum period.These findings have implications for early detection and care of women at risk for developing depression.

  9. Periodic solutions of nonlinear vibrating beams

    Directory of Open Access Journals (Sweden)

    J. Berkovits

    2003-01-01

    Full Text Available The aim of this paper is to prove new existence and multiplicity results for periodic semilinear beam equation with a nonlinear time-independent perturbation in case the period is not prescribed. Since the spectrum of the linear part varies with the period, the solvability of the equation depends crucially on the period which can be chosen as a free parameter. Since the period of the external forcing is generally unknown a priori, we consider the following natural problem. For a given time-independent nonlinearity, find periods T for which the equation is solvable for any T-periodic forcing. We will also deal with the existence of multiple solutions when the nonlinearity interacts with the spectrum of the linear part. We show that under certain conditions multiple solutions do exist for any small forcing term with suitable period T. The results are obtained via generalized Leray-Schauder degree and reductions to invariant subspaces.

  10. Existence of Periodic Orbits with Zeno Behavior in Completed Lagrangian Hybrid Systems

    OpenAIRE

    Or, Yizhar; Ames, Aaron D.

    2009-01-01

    In this paper, we consider hybrid models of mechanical systems undergoing impacts, Lagrangian hybrid systems, and study their periodic orbits in the presence of Zeno behavior-an infinite number of impacts occurring in finite time. The main result of this paper is explicit conditions under which the existence of stable periodic orbits for a Lagrangian hybrid system with perfectly plastic impacts implies the existence of periodic orbits in the same system with non-plastic impacts. Such periodic...

  11. Fluid mechanics

    International Nuclear Information System (INIS)

    Granger, R.A.

    1985-01-01

    This text offers the most comprehensive approach available to fluid mechanics. The author takes great care to insure a physical understanding of concepts grounded in applied mathematics. The presentation of theory is followed by engineering applications, helping students develop problem-solving skills from the perspective of a professional engineer. Extensive use of detailed examples reinforces the understanding of theoretical concepts

  12. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  13. Period-dependent source rupture behavior of the 2011 Tohoku earthquake estimated by multi period-band Bayesian waveform inversion

    Science.gov (United States)

    Kubo, H.; Asano, K.; Iwata, T.; Aoi, S.

    2014-12-01

    rupture off Fukushima at 90-135 s. The dominant-period difference of the seismic-wave radiation between two deep ruptures off Miyagi may result from the mechanism that small-scale heterogeneities on the fault are removed by the first rupture. This difference can be also interpreted by the concept of multi-scale dynamic rupture (Ide & Aochi, 2005).

  14. Periodic pulling of the drift instability in a thermal plasma

    International Nuclear Information System (INIS)

    Abrams, R.H. Jr.

    1970-01-01

    The primary objective of this thesis is to show that a mode of oscillation in a plasma can be represented by a van der Pol oscillator. The results of an experiment performed on a drift wave in a Q-machine are interpreted in terms of a mechanism developed by Lashinsky. The mechanism, called periodic pulling, predicts a specific kind of spectrum for certain experimental conditions when a van der Pol oscillator is perturbed by a small signal. The observed spectrum, along with other observations, lends credence to the van der Pol oscillator model of a plasma mode

  15. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used in...

  16. 39 CFR 121.2 - Periodicals.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Periodicals. 121.2 Section 121.2 Postal Service UNITED STATES POSTAL SERVICE POST OFFICE SERVICES [DOMESTIC MAIL] SERVICE STANDARDS FOR MARKET-DOMINANT MAIL PRODUCTS § 121.2 Periodicals. (a) End-to-End. (1) For all SCF turnaround Periodicals properly...

  17. 27 CFR 70.244 - Payroll period.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Payroll period. 70.244... Excise and Special (Occupational) Tax Limitations § 70.244 Payroll period. For purpose of determining the... established calendar period regularly used by the employer or other person levied upon for payroll or payment...

  18. 40 CFR 35.9035 - Budget period.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Budget period. 35.9035 Section 35.9035... ASSISTANCE Financial Assistance for the National Estuary Program § 35.9035 Budget period. An applicant may choose its budget period in consultation with and subject to the approval of the Regional Administrator. ...

  19. 10 CFR 603.1295 - Periodic audit.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Periodic audit. 603.1295 Section 603.1295 Energy... Used in this Part § 603.1295 Periodic audit. An audit of a participant, performed at an agreed-upon... an audit may cover. A periodic audit of a participant differs from an award-specific audit of an...

  20. 32 CFR 37.1325 - Periodic audit.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Periodic audit. 37.1325 Section 37.1325 National... TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in This Part § 37.1325 Periodic audit. An audit of... awards. Appendix C to this part describes what such an audit may cover. A periodic audit of a participant...

  1. 49 CFR 236.588 - Periodic test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Periodic test. 236.588 Section 236.588..., Train Control and Cab Signal Systems Inspection and Tests; Locomotive § 236.588 Periodic test. Except as provided in § 236.586, periodic test of the automatic train stop, train control, or cab signal apparatus...

  2. 47 CFR 22.1035 - Construction period.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Construction period. 22.1035 Section 22.1035 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1035 Construction period. The construction period (see § 22.142) for...

  3. Handgun waiting periods reduce gun deaths.

    Science.gov (United States)

    Luca, Michael; Malhotra, Deepak; Poliquin, Christopher

    2017-11-14

    Handgun waiting periods are laws that impose a delay between the initiation of a purchase and final acquisition of a firearm. We show that waiting periods, which create a "cooling off" period among buyers, significantly reduce the incidence of gun violence. We estimate the impact of waiting periods on gun deaths, exploiting all changes to state-level policies in the Unites States since 1970. We find that waiting periods reduce gun homicides by roughly 17%. We provide further support for the causal impact of waiting periods on homicides by exploiting a natural experiment resulting from a federal law in 1994 that imposed a temporary waiting period on a subset of states. Copyright © 2017 the Author(s). Published by PNAS.

  4. A highly specific test for periodicity

    Energy Technology Data Exchange (ETDEWEB)

    Ansmann, Gerrit, E-mail: gansmann@uni-bonn.de [Department of Epileptology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn (Germany); Helmholtz Institute for Radiation and Nuclear Physics, University of Bonn, Nussallee 14–16, 53115 Bonn (Germany); Interdisciplinary Center for Complex Systems, University of Bonn, Brühler Straße 7, 53175 Bonn (Germany)

    2015-11-15

    We present a method that allows to distinguish between nearly periodic and strictly periodic time series. To this purpose, we employ a conservative criterion for periodicity, namely, that the time series can be interpolated by a periodic function whose local extrema are also present in the time series. Our method is intended for the analysis of time series generated by deterministic time-continuous dynamical systems, where it can help telling periodic dynamics from chaotic or transient ones. We empirically investigate our method's performance and compare it to an approach based on marker events (or Poincaré sections). We demonstrate that our method is capable of detecting small deviations from periodicity and outperforms the marker-event-based approach in typical situations. Our method requires no adjustment of parameters to the individual time series, yields the period length with a precision that exceeds the sampling rate, and its runtime grows asymptotically linear with the length of the time series.

  5. A highly specific test for periodicity

    International Nuclear Information System (INIS)

    Ansmann, Gerrit

    2015-01-01

    We present a method that allows to distinguish between nearly periodic and strictly periodic time series. To this purpose, we employ a conservative criterion for periodicity, namely, that the time series can be interpolated by a periodic function whose local extrema are also present in the time series. Our method is intended for the analysis of time series generated by deterministic time-continuous dynamical systems, where it can help telling periodic dynamics from chaotic or transient ones. We empirically investigate our method's performance and compare it to an approach based on marker events (or Poincaré sections). We demonstrate that our method is capable of detecting small deviations from periodicity and outperforms the marker-event-based approach in typical situations. Our method requires no adjustment of parameters to the individual time series, yields the period length with a precision that exceeds the sampling rate, and its runtime grows asymptotically linear with the length of the time series

  6. Mechanical engineering

    International Nuclear Information System (INIS)

    1988-01-01

    The Mechanical Engineering Division provides the other NAC divisions with design and construction services. Items of special mechanical significance are discussed here. The projects which received major design attention during the past year were: a coupling capacitor for SPC2; a bending magnet and solenoid for ECR ion source; a scanner for outer orbits of the SSC; a scattering chamber for an experimental beamline; a beam swinger; a rotary target magazine for isotope production; a robot arm for isotope production; an isotope transport system and a target cooling system for isotope production. The major projects that were under construction are: a magnetic spectrometer; a second injector cyclotron (SPC2) and extensions to the high-energy beamlines. 4 figs

  7. Statistical mechanics

    CERN Document Server

    Schwabl, Franz

    2006-01-01

    The completely revised new edition of the classical book on Statistical Mechanics covers the basic concepts of equilibrium and non-equilibrium statistical physics. In addition to a deductive approach to equilibrium statistics and thermodynamics based on a single hypothesis - the form of the microcanonical density matrix - this book treats the most important elements of non-equilibrium phenomena. Intermediate calculations are presented in complete detail. Problems at the end of each chapter help students to consolidate their understanding of the material. Beyond the fundamentals, this text demonstrates the breadth of the field and its great variety of applications. Modern areas such as renormalization group theory, percolation, stochastic equations of motion and their applications to critical dynamics, kinetic theories, as well as fundamental considerations of irreversibility, are discussed. The text will be useful for advanced students of physics and other natural sciences; a basic knowledge of quantum mechan...

  8. Fracture mechanics

    International Nuclear Information System (INIS)

    Miannay, D.P.

    1995-01-01

    This book entitle ''Fracture Mechanics'', the first one of the monograph ''Materiologie'' is geared to design engineers, material engineers, non destructive inspectors and safety experts. This book covers fracture mechanics in isotropic homogeneous continuum. Only the monotonic static loading is considered. This book intended to be a reference with the current state of the art gives the fundamental of the issues under concern and avoids the developments too complicated or not yet mastered for not making reading cumbersome. The subject matter is organized as going from an easy to a more complicated level and thus follows the chronological evolution in the field. Similarly the microscopic scale is considered before the macroscopic scale, the physical understanding of phenomena linked to the experimental observation of the material preceded the understanding of the macroscopic behaviour of structures. In this latter field the relatively recent contribution of finite element computations with some analogy with the experimental observation is determining. However more sensitive analysis is not skipped

  9. Statistical mechanics

    CERN Document Server

    Jana, Madhusudan

    2015-01-01

    Statistical mechanics is self sufficient, written in a lucid manner, keeping in mind the exam system of the universities. Need of study this subject and its relation to Thermodynamics is discussed in detail. Starting from Liouville theorem gradually, the Statistical Mechanics is developed thoroughly. All three types of Statistical distribution functions are derived separately with their periphery of applications and limitations. Non-interacting ideal Bose gas and Fermi gas are discussed thoroughly. Properties of Liquid He-II and the corresponding models have been depicted. White dwarfs and condensed matter physics, transport phenomenon - thermal and electrical conductivity, Hall effect, Magneto resistance, viscosity, diffusion, etc. are discussed. Basic understanding of Ising model is given to explain the phase transition. The book ends with a detailed coverage to the method of ensembles (namely Microcanonical, canonical and grand canonical) and their applications. Various numerical and conceptual problems ar...

  10. Pseudomonas fluorescens' view of the periodic table.

    Science.gov (United States)

    Workentine, Matthew L; Harrison, Joe J; Stenroos, Pernilla U; Ceri, Howard; Turner, Raymond J

    2008-01-01

    Growth in a biofilm modulates microbial metal susceptibility, sometimes increasing the ability of microorganisms to withstand toxic metal species by several orders of magnitude. In this study, a high-throughput metal toxicity screen was initiated with the aim of correlating biological toxicity data in planktonic and biofilm cells to the physiochemical properties of metal ions. To this end, Pseudomonas fluorescens ATCC 13525 was grown in the Calgary Biofilm Device (CBD) and biofilms and planktonic cells of this microorganism were exposed to gradient arrays of different metal ions. These arrays included 44 different metals with representative compounds that spanned every group of the periodic table (except for the halogens and noble gases). The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) values were obtained after exposing the biofilms to metal ions for 4 h. Using these values, metal ion toxicity was correlated to the following ion-specific physicochemical parameters: standard reduction-oxidation potential, electronegativity, the solubility product of the corresponding metal-sulfide complex, the Pearson softness index, electron density and the covalent index. When the ions were grouped according to outer shell electron structure, we found that heavy metal ions gave the strongest correlations to these parameters and were more toxic on average than the other classes of the ions. Correlations were different for biofilms than for planktonic cells, indicating that chemical mechanisms of metal ion toxicity differ between the two modes of growth. We suggest that biofilms can specifically counter the toxic effects of certain physicochemical parameters, which may contribute to the increased ability of biofilms to withstand metal toxicity.

  11. Mechanical engineering

    CERN Document Server

    Darbyshire, Alan

    2010-01-01

    Alan Darbyshire's best-selling text book provides five-star high quality content to a potential audience of 13,000 engineering students. It explains the most popular specialist units of the Mechanical Engineering, Manufacturing Engineering and Operations & Maintenance Engineering pathways of the new 2010 BTEC National Engineering syllabus. This challenging textbook also features contributions from specialist lecturers, ensuring that no stone is left unturned.

  12. Impact Mechanics

    Science.gov (United States)

    Stronge, W. J.

    2004-03-01

    Impact mechanics is concerned with the reaction forces that develop during a collision and the dynamic response of structures to these reaction forces. The subject has a wide range of engineering applications, from designing sports equipment to improving the crashworthiness of automobiles. This book develops several different methodologies for analysing collisions between structures. These range from rigid body theory for structures that are stiff and compact, to vibration and wave analyses for flexible structures. The emphasis is on low-speed impact where damage is local to the small region of contact between the colliding bodies. The analytical methods presented give results that are more robust or less sensitive to initial conditions than have been achieved hitherto. As a text, Impact Mechanics builds upon foundation courses in dynamics and strength of materials. It includes numerous industrially relevant examples and end-of-chapter homework problems drawn from industry and sports. Practising engineers will also find the methods presented in this book useful in calculating the response of a mechanical system to impact.

  13. Seismic isolation of two dimensional periodic foundations

    International Nuclear Information System (INIS)

    Yan, Y.; Mo, Y. L.; Laskar, A.; Cheng, Z.; Shi, Z.; Menq, F.; Tang, Y.

    2014-01-01

    Phononic crystal is now used to control acoustic waves. When the crystal goes to a larger scale, it is called periodic structure. The band gaps of the periodic structure can be reduced to range from 0.5 Hz to 50 Hz. Therefore, the periodic structure has potential applications in seismic wave reflection. In civil engineering, the periodic structure can be served as the foundation of upper structure. This type of foundation consisting of periodic structure is called periodic foundation. When the frequency of seismic waves falls into the band gaps of the periodic foundation, the seismic wave can be blocked. Field experiments of a scaled two dimensional (2D) periodic foundation with an upper structure were conducted to verify the band gap effects. Test results showed the 2D periodic foundation can effectively reduce the response of the upper structure for excitations with frequencies within the frequency band gaps. When the experimental and the finite element analysis results are compared, they agree well with each other, indicating that 2D periodic foundation is a feasible way of reducing seismic vibrations.

  14. Mechanism of nanofiber crimp

    Directory of Open Access Journals (Sweden)

    Chen Rou-Xi

    2013-01-01

    Full Text Available Fabrication of crimped fibers has been caught much attention recently due to remarkable improvement surface-to-volume ratio. The precise mechanism of the fiber crimp is, however, rare and preliminary. This paper finds that pulsation of fibers is the key factor for fiber crimp, and its configuration (wave formation corresponds to its nature frequency after solidification. Crimping performance can be improved by temperature control of the uncrimped fibers. In the paper, polylactide/ dimethylfomamide solution is fabricated into crimped nanofibers by the bubble electrospinning, an approximate period- amplitude relationship of the wave formation is obtained.

  15. Quantum mechanics

    International Nuclear Information System (INIS)

    Basdevant, J.L.; Dalibard, J.; Joffre, M.

    2008-01-01

    All physics is quantum from elementary particles to stars and to the big-bang via semi-conductors and chemistry. This theory is very subtle and we are not able to explain it without the help of mathematic tools. This book presents the principles of quantum mechanics and describes its mathematical formalism (wave function, Schroedinger equation, quantum operators, spin, Hamiltonians, collisions,..). We find numerous applications in the fields of new technologies (maser, quantum computer, cryptography,..) and in astrophysics. A series of about 90 exercises with their answers is included. This book is based on a physics course at a graduate level. (A.C.)

  16. Fluid mechanics

    International Nuclear Information System (INIS)

    Paraschivoiu, I.; Prud'homme, M.; Robillard, L.; Vasseur, P.

    2003-01-01

    This book constitutes at the same time theoretical and practical base relating to the phenomena associated with fluid mechanics. The concept of continuum is at the base of the approach developed in this work. The general advance proceeds of simple balances of forces as into hydrostatic to more complex situations or inertias, the internal stresses and the constraints of Reynolds are taken into account. This advance is not only theoretical but contains many applications in the form of solved problems, each chapter ending in a series of suggested problems. The major part of the applications relates to the incompressible flows

  17. Reaction mechanisms

    International Nuclear Information System (INIS)

    Nguyen Trong Anh

    1988-01-01

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported [fr

  18. Quantum mechanics

    CERN Document Server

    Rae, Alastair I M

    2007-01-01

    PREFACESINTRODUCTION The Photoelectric Effect The Compton Effect Line Spectra and Atomic Structure De Broglie Waves Wave-Particle Duality The Rest of This Book THE ONE-DIMENSIONAL SCHRÖDINGER EQUATIONS The Time-Dependent Schrödinger Equation The Time-Independent Schrödinger Equation Boundary ConditionsThe Infinite Square Well The Finite Square Well Quantum Mechanical Tunneling The Harmonic Oscillator THE THREE-DIMENSIONAL SCHRÖDINGER EQUATIONS The Wave Equations Separation in Cartesian Coordinates Separation in Spherical Polar Coordinates The Hydrogenic Atom THE BASIC POSTULATES OF QUANTUM MEC

  19. Quantum mechanics

    CERN Document Server

    Mandl, Franz

    1992-01-01

    The Manchester Physics Series General Editors: D. J. Sandiford; F. Mandl; A. C. Phillips Department of Physics and Astronomy, University of Manchester Properties of Matter B. H. Flowers and E. Mendoza Optics Second Edition F. G. Smith and J. H. Thomson Statistical Physics Second Edition F. Mandl Electromagnetism Second Edition I. S. Grant and W. R. Phillips Statistics R. J. Barlow Solid State Physics Second Edition J. R. Hook and H. E. Hall Quantum Mechanics F. Mandl Particle Physics Second Edition B. R. Martin and G. Shaw The Physics of Stars Second Edition A. C. Phillips Computing for Scient

  20. Discrete symmetries in periodic-orbit theory

    International Nuclear Information System (INIS)

    Robbins, J.M.

    1989-01-01

    The application of periodic-orbit theory to systems which possess a discrete symmetry is considered. A semiclassical expression for the symmetry-projected Green's function is obtained; it involves a sum over classical periodic orbits on a symmetry-reduced phase space, weighted by characters of the symmetry group. These periodic orbits correspond to trajectories on the full phase space which are not necessarily periodic, but whose end points are related by symmetry. If the symmetry-projected Green's functions are summed, the contributions of the unperiodic orbits cancel, and one recovers the usual periodic-orbit sum for the full Green's function. Several examples are considered, including the stadium billiard, a particle in a periodic potential, the Sinai billiard, the quartic oscillator, and the rotational spectrum of SF 6

  1. How periodic are terahertz quantum cascade lasers?

    International Nuclear Information System (INIS)

    Kubis, T; Vogl, P

    2009-01-01

    We apply a novel non-equilibrium Green's function method for open quantum devices to analyze quantum cascade lasers. We find the carrier distribution in typical resonant phonon THz-QCLs to develop a periodicity that differs from the geometric periodicity of the QCL. We propose a design improvement that thermalizes electrons at threshold bias and thereby pins the electron density to the QCL periodicity.

  2. How periodic are terahertz quantum cascade lasers?

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, T; Vogl, P, E-mail: tillmann.kubis@wsi.tum.d [Walter Schottky Institute, Technische Universitaet Muenchen, Am Coulombwall 3, 85748 Garching (Germany)

    2009-11-15

    We apply a novel non-equilibrium Green's function method for open quantum devices to analyze quantum cascade lasers. We find the carrier distribution in typical resonant phonon THz-QCLs to develop a periodicity that differs from the geometric periodicity of the QCL. We propose a design improvement that thermalizes electrons at threshold bias and thereby pins the electron density to the QCL periodicity.

  3. Southern hemisphere searches for short period pulsars

    International Nuclear Information System (INIS)

    Manchester, R.N.

    1984-01-01

    Two searches of the southern sky for short period pulsars are briefly described. The first, made using the 64-m telescope at Parkes, is sensitive to pulsars with periods greater than about 10 ms and the second, made using the Molonglo radio telescope, has sensitivity down to periods of about 1.5 ms. Four pulsars were found in the Parkes survey and none in the Molonglo survey, although analysis of the latter is as yet incomplete. 10 references, 1 figure, 2 tables

  4. Long-Period Variability in o Ceti

    Science.gov (United States)

    Templeton, Matthew R.; Karovska, Margarita

    2009-02-01

    We carried out a new and sensitive search for long-period variability in the prototype of the Mira class of long-period pulsating variables, o Ceti (Mira A), the closest and brightest Mira variable. We conducted this search using an unbroken light curve from 1902 to the present, assembled from the visual data archives of five major variable star observing organizations from around the world. We applied several time-series analysis techniques to search for two specific kinds of variability: long secondary periods (LSPs) longer than the dominant pulsation period of ~333 days, and long-term period variation in the dominant pulsation period itself. The data quality is sufficient to detect coherent periodic variations with photometric amplitudes of 0.05 mag or less. We do not find evidence for coherent LSPs in o Ceti to a limit of 0.1 mag, where the amplitude limit is set by intrinsic, stochastic, low-frequency variability of approximately 0.1 mag. We marginally detect a slight modulation of the pulsation period similar in timescale to that observed in the Miras with meandering periods, but with a much lower period amplitude of ±2 days. However, we do find clear evidence of a low-frequency power-law component in the Fourier spectrum of o Ceti's long-term light curve. The amplitude of this stochastic variability is approximately 0.1 mag at a period of 1000 days, and it exhibits a turnover for periods longer than this. This spectrum is similar to the red noise spectra observed in red supergiants.

  5. Mechanisms in ancient Chinese books with illustrations

    CERN Document Server

    Hsiao, Kuo-Hung

    2014-01-01

    This book presents a unique approach for studying mechanisms and machines with drawings that were depicted unclearly in ancient Chinese books. The historical, cultural and technical backgrounds of the mechanisms are explained, and various mechanisms described and illustrated in ancient books are introduced. By utilizing the idea for the conceptual design of modern mechanisms, all feasible designs of ancient mechanisms with uncertain members and joints that meet the technical standards of the subjects’ time periods are synthesized systematically. Ancient Chinese crossbows (the original crossbow and repeating crossbows), textile mechanisms (silk-reeling mechanism, spinning mechanisms, and looms), and many other artisan's tool mechanisms are used as illustrated examples.  Such an approach provides a logical method for the reconstruction designs of ancient mechanisms with uncertain structures. It also provides an innovative direction for researchers to further identify the original structures of mechanisms...

  6. Epidural Analgesia in the Postoperative Period

    National Research Council Canada - National Science Library

    Mathsen, Curtis

    2001-01-01

    .... This descriptive study was conducted to determine which surgical patients experienced the most analgesia with the fewest side effects when receiving epidural analgesia in the postoperative period...

  7. Project 2nd Periodic Report - Section 2

    DEFF Research Database (Denmark)

    Healy, Mark; Knowles, Emma; Johnstone, Cameron

    The work described in this publication has received support from the European Community - Research Infrastructure Action under the FP7 “Capacities” Specific Programme through grant agreement number 262552, MaRINET. Project Periodic Report. 2nd Period: October 2012 – March 2014 inclusive.......The work described in this publication has received support from the European Community - Research Infrastructure Action under the FP7 “Capacities” Specific Programme through grant agreement number 262552, MaRINET. Project Periodic Report. 2nd Period: October 2012 – March 2014 inclusive....

  8. Periodic Continuing Disability Review Case Backlog

    Data.gov (United States)

    Social Security Administration — The Social Security Administration (SSA) conducts periodic CDRs to ensure that only those beneficiaries who remain disabled continue to receive monthly benefits. The...

  9. Word learning mechanisms.

    Science.gov (United States)

    He, Angela Xiaoxue; Arunachalam, Sudha

    2017-07-01

    How do children acquire the meanings of words? Many word learning mechanisms have been proposed to guide learners through this challenging task. Despite the availability of rich information in the learner's linguistic and extralinguistic input, the word-learning task is insurmountable without such mechanisms for filtering through and utilizing that information. Different kinds of words, such as nouns denoting object concepts and verbs denoting event concepts, require to some extent different kinds of information and, therefore, access to different kinds of mechanisms. We review some of these mechanisms to examine the relationship between the input that is available to learners and learners' intake of that input-that is, the organized, interpreted, and stored representations they form. We discuss how learners segment individual words from the speech stream and identify their grammatical categories, how they identify the concepts denoted by these words, and how they refine their initial representations of word meanings. WIREs Cogn Sci 2017, 8:e1435. doi: 10.1002/wcs.1435 This article is categorized under: Linguistics > Language Acquisition Psychology > Language. © 2017 Wiley Periodicals, Inc.

  10. Mechanical integrity of canisters

    International Nuclear Information System (INIS)

    Nilsson, Fred

    1992-12-01

    This document constitutes the final report from 'SKBs reference group for mechanical integrity of canisters for spent nuclear fuel'. A complete list of all reports initiated by the reference group can be found in the summary report in this document. The main task of the reference group has been to advice SKB regarding the choice (ranking of alternatives) of canister type for different types of storage. The choice should be based on requirements of impermeability for a given time period and identification of possible limiting mechanisms. The main conclusions from the work were: From mechanical point of view, low phosphorous oxygen free copper (Cu-OFP) is a preferred canisters material. It exhibits satisfactory ductility both during tensile and creep testing. The residual stresses in the canisters are of such a magnitude that the estimated time to creep rupture with the data obtained for the Cu-OFP material is essentially infinite. Based on the present knowledge of stress corrosion cracking of copper there appears to be a small risk for such to occur in the projected environment. This risk need some further study. Rock shear movements of the size of 10 cm should pose no direct threat to the integrity of the canisters. Considering mechanical integrity, the composite copper/steel canister is an advantageous alternative. The recommendations for further research included continued studies of the creep properties of copper and of stress corrosion cracking. However, the studies should focus more directly on the design and fabrication aspect of the canister

  11. Introductory Education for Mechanical Engineering by Exercise in Mechanical Disassembly

    Science.gov (United States)

    Matsui, Yoshio; Asakawa, Naoki; Iwamori, Satoru

    An introductory program “Exercise for engineers in mechanical disassembly” is an exercise that ten students of every team disassemble a motor scooter to the components and then assemble again to the initial form in 15 weeks. The purpose of this program is to introduce mechanical engineering by touching the real machine and learning how it is composed from various mechanical parts to the students at the early period after the entrance into the university. Additional short lectures by young teachers and a special lecture by a top engineer in the industry encourage the students to combine the actual machine and the mechanical engineering subjects. Furthermore, various educations such as group leader system, hazard prediction training, parts filing are included in this program. As a result, students recognize the importance of the mechanical engineering study and the way of group working.

  12. Trends and interaction of polypharmacy and potentially inappropriate prescribing in primary care over 15 years in Ireland: a repeated cross-sectional study.

    LENUS (Irish Health Repository)

    Moriarty, Frank

    2015-03-01

    To examine: (1) changes in polypharmacy in 1997, 2002, 2007 and 2012 and; (2) changes in potentially inappropriate prescribing (PIP) prevalence and the relationship between PIP and polypharmacy in individuals aged ≥65 years over this period in Ireland.

  13. Prevalence of diseases among sheep and goats in Edo State, Nigeria

    African Journals Online (AJOL)

    Clinical records of small ruminant (Sheep and Goat) diseases treated were collected from the veterinary clinics, Ministry of Agriculture and Natural Resources of three Local Government areas in Edo state, for a period of five years (1997-2002). To identify the disease occurrence and prevalence as it militates against the ...

  14. 38 CFR 3.252 - Annual income; pension; Mexican border period and later war periods.

    Science.gov (United States)

    2010-07-01

    ...; Mexican border period and later war periods. 3.252 Section 3.252 Pensions, Bonuses, and Veterans' Relief... Dependency, Income and Estate § 3.252 Annual income; pension; Mexican border period and later war periods. (a) Annual income limitations; old-law pension. Where the right to old-law pension is payable under section...

  15. Quantum mechanics

    International Nuclear Information System (INIS)

    Ghatak, A.K.; Lokanathan, S.

    1975-01-01

    This textbook on quantum mechanics is intended for students at the graduate and post-graduate level. A balanced account of theory and applications is presented. Emphasis is laid on making results plausible and methods to be followed in solving problems. The various chapters in the book are devoted to the following: (1) Wave particle duality and uncertainty principle (2) Wave packets and time-dependent Schroedinger equation (3) Simple solutions of Schroedinger equation (4) Vector spaces and linear operators : Dirac notation (5) Angular momentum and spin (6) Addition of angular momenta (7) Time independent perturbation theory (8) The variational method (9) The WKB approximation (10) Elementary theory of scattering (11) Time-dependent perturbation theory (12) Motion in a magnetic field (13) Interaction of radiation with matter and (14) Relativistic theory. (A.K.)

  16. Soil Mechanics

    DEFF Research Database (Denmark)

    Gottlieb, Sara Wisbech Jacobsen; Hededal, Ole; Foged, Niels Nielsen

    by stress and strain and their behaviour is convergent. Numerical models exist that simulate clay behaviour over time, the majority derived from Perzyna (1966). An empirical expression for the ‘index of viscosity’ was derived by Leinenkugel (1976). This suggests the change of strain rate is proportional......It is widely accepted that there is a connection between the undrained shear strength and the strain rate. Thixotropy and creep behaviour are connected to the mechanical properties of clay. Thixotropy is the ability of clay to recover its shear strength over time when the shear stress is released...... of equilibrium in viscosity over time at a given stress level for a thixotropic fluid. In rheology, this type of material is known as a non-Newtonian thixotropic fluid. A Newtonian fluid has no yield stress, resembling a strictly elastic material; whereas a non-Newtonian fluid cannot be expressed by a direct...

  17. 46 CFR 403.115 - Accounting period.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Accounting period. 403.115 Section 403.115 Shipping COAST GUARD (GREAT LAKES PILOTAGE), DEPARTMENT OF HOMELAND SECURITY GREAT LAKES PILOTAGE UNIFORM ACCOUNTING SYSTEM General § 403.115 Accounting period. Each Association subject to this part shall maintain...

  18. 18 CFR 367.5 - Accounting period.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Accounting period. 367.5 Section 367.5 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... Instructions § 367.5 Accounting period. Each service company must keep its books on a monthly basis so that for...

  19. 24 CFR 221.775 - Option period.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Option period. 221.775 Section 221.775 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... § 221.775 Option period. The mortgagee may exercise its option to assign within one year following the...

  20. 42 CFR 409.60 - Benefit periods.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Benefit periods. 409.60 Section 409.60 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM HOSPITAL INSURANCE BENEFITS Scope of Hospital Insurance Benefits § 409.60 Benefit periods. (a) When benefit...

  1. 28 CFR 524.75 - Periodic review.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Periodic review. 524.75 Section 524.75... TRANSFER CLASSIFICATION OF INMATES Central Inmate Monitoring (CIM) System § 524.75 Periodic review. The Warden shall ensure that the status of an inmate's CIM assignment is considered at each program review...

  2. 50 CFR 424.21 - Periodic review.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Periodic review. 424.21 Section 424.21... SPECIES AND DESIGNATING CRITICAL HABITAT Revision of the Lists § 424.21 Periodic review. At least once every 5 years, the Secretary shall conduct a review of each listed species to determine whether it...

  3. Attractors for discrete periodic dynamical systems

    Science.gov (United States)

    John E. Franke; James F. Selgrade

    2003-01-01

    A mathematical framework is introduced to study attractors of discrete, nonautonomous dynamical systems which depend periodically on time. A structure theorem for such attractors is established which says that the attractor of a time-periodic dynamical system is the unin of attractors of appropriate autonomous maps. If the nonautonomous system is a perturbation of an...

  4. Discontinuous Spirals of Stable Periodic Oscillations

    DEFF Research Database (Denmark)

    Sack, Achim; Freire, Joana G.; Lindberg, Erik

    2013-01-01

    We report the experimental discovery of a remarkable organization of the set of self-generated periodic oscillations in the parameter space of a nonlinear electronic circuit. When control parameters are suitably tuned, the wave pattern complexity of the periodic oscillations is found to increase...

  5. Multi-periodic nanostructures for photon control

    DEFF Research Database (Denmark)

    Kluge, Christian; Adam, Jost; Barié, Nicole

    2014-01-01

    We propose multi-periodic nanostructures yielded by superposition of multiple binary gratings for wide control over photon emission in thin-film devices. We present wavelength- and angle-resolved photoluminescence measurements of multi-periodically nanostructured organic light-emitting layers...

  6. Quantized gauge invariant periodic TDHF solutions

    International Nuclear Information System (INIS)

    Kan, K.-K.; Griffin, J.J.; Lichtner, P.C.; Dworzecka, M.

    1979-01-01

    Time-dependent Hartree-Fock (TDHF) is used to study steady state large amplitude nuclear collective motions, such as vibration and rotation. As is well known the small amplitude TDHF leads to the RPA equation. The analysis of periodicity in TDHF is not trivial because TDHF is a nonlinear theory and it is not known under what circumstances a nonlinear theory can support periodic solutions. It is also unknown whether such periodic solution, if they exist, form a continuous or a discrete set. But, these properties may be important in obtaining the energy spectrum of the collective states from the TDHF description. The periodicity and Gauge Invariant Periodicity of solutions are investigated for that class of models whose TDHF solutions depend on time through two parameters. In such models TDHF supports a continuous family of periodic solutions, but only a discrete subset of these is gauge invariant. These discrete Gauge Invariant Periodic solutions obey the Bohr-Summerfeld quantization rule. The energy spectrum of the Gauge Invariant Periodic solutions is compared with the exact eigenergies in one specific example

  7. 20 CFR 410.501 - Payment periods.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Payment periods. 410.501 Section 410.501 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Payment of Benefits § 410.501 Payment periods. Benefits are paid to...

  8. The decreasing period of AG Phe

    International Nuclear Information System (INIS)

    Cerruti, M.A.

    1986-01-01

    Seven UBV photoelectric times of minimum light are presented. They shift the photographically known period 0 . d 613 to 0 . d 380. The improvement of the light elements leads to a reliable shortening of the period. A rough determination of the mass-ratio permitted to give an estimate of the mass transfer in the system. 13 refs., 1 fig., 1 tab. (author)

  9. Selecting Full-Text Undergraduate Periodicals Databases.

    Science.gov (United States)

    Still, Julie M.; Kassabian, Vibiana

    1999-01-01

    Examines how libraries and librarians can compare full-text general periodical indices, using ProQuest Direct, Periodical Abstracts (via Ovid), and EBSCOhost as examples. Explores breadth and depth of coverage; manipulation of results (email/download/print); ease of use (searching); and indexing quirks. (AEF)

  10. 20 CFR 655.205 - Recruitment period.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Recruitment period. 655.205 Section 655.205... FOREIGN WORKERS IN THE UNITED STATES Labor Certification Process for Logging Employment and Non-H-2A Agricultural Employment § 655.205 Recruitment period. (a) If the OFLC Administrator determines that the...

  11. Buffer Overflow Period in a MAP Queue

    Directory of Open Access Journals (Sweden)

    Andrzej Chydzinski

    2007-01-01

    Full Text Available The buffer overflow period in a queue with Markovian arrival process (MAP and general service time distribution is investigated. The results include distribution of the overflow period in transient and stationary regimes and the distribution of the number of cells lost during the overflow interval. All theorems are illustrated via numerical calculations.

  12. Shock dynamics in layered periodic media

    KAUST Repository

    Ketcheson, David I.; Leveque, Randall J.

    2012-01-01

    of shock waves in a one-dimensional periodic layered medium by a computational study of time-reversibility and entropy evolution. We find that periodic layered media tend to inhibit shock formation. For small initial conditions and large impedance variation

  13. Survival period, infectivity and morphological composition of ...

    African Journals Online (AJOL)

    Open Access DOWNLOAD FULL TEXT ... At the end of each maintenance period (hours), three clean albino mice were ... for up to 12 and 24 hours respectively were infective for the mice inoculation test. ... period (21.0days) higher peak parasitaemia (15-20 parasites per field) and higher population of slender forms.

  14. Online Periodic Table: A Cautionary Note

    Science.gov (United States)

    Izci, Kemal; Barrow, Lloyd H.; Thornhill, Erica

    2013-01-01

    The purpose of this study was (a) to evaluate ten online periodic table sources for their accuracy and (b) to compare the types of information and links provided to users. Limited studies have been reported on online periodic table (Diener and Moore 2011; Slocum and Moore in "J Chem Educ" 86(10):1167, 2009). Chemistry students'…

  15. The periodic table of elementary particles

    International Nuclear Information System (INIS)

    Bhattacharjee, B.J.

    1994-01-01

    It is shown that a periodic classification of elementary particles (eps) may be done with the basic properties of eps: viz. mass, spin and parity. Further application of spacing rule and GMO mass formulae show repetitions at very regular intervals. It is found that properties of eps are periodic function of rest mass. (author). 17 refs., 6 tabs

  16. The periodic table of elementary particles

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, B J [St. Anthony' s College, Shillong (India). Dept. of Physics

    1994-01-01

    It is shown that a periodic classification of elementary particles (eps) may be done with the basic properties of eps: viz. mass, spin and parity. Further application of spacing rule and GMO mass formulae show repetitions at very regular intervals. It is found that properties of eps are periodic function of rest mass. (author). 17 refs., 6 tabs.

  17. 12 CFR 226.7 - Periodic statement.

    Science.gov (United States)

    2010-01-01

    ... consumer with a periodic statement that discloses the following items, to the extent applicable: (a... convenience of the user, the revised text is set forth as follows: § 226.7 Periodic statement. (a) Rules... consumers may obtain from the creditor more information about the balance computation method and how...

  18. 5 CFR 9901.512 - Probationary periods.

    Science.gov (United States)

    2010-01-01

    ... 9901.512 Administrative Personnel DEPARTMENT OF DEFENSE HUMAN RESOURCES MANAGEMENT AND LABOR RELATIONS SYSTEMS (DEPARTMENT OF DEFENSE-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF DEFENSE NATIONAL SECURITY... Probationary periods. (a) Initial probationary period. (1) An employee who is given a career, career...

  19. Resonances in a periodically driven bosonic system

    NARCIS (Netherlands)

    Quelle, Anton; de Morais Smith, Cristiane

    2017-01-01

    Periodically driven systems are a common topic in modern physics. In optical lattices specifically, driving is at the origin of many interesting phenomena. However, energy is not conserved in driven systems, and under periodic driving, heating of a system is a real concern. In an effort to better

  20. Almost periodic Hamiltonians: an algebraic approach

    International Nuclear Information System (INIS)

    Bellissard, J.

    1981-07-01

    We develop, by analogy with the study of periodic potential, an algebraic theory for almost periodic hamiltonians, leading to a generalized Bloch theorem. This gives rise to results concerning the spectral measures of these operators in terms of those of the corresponding Bloch hamiltonians

  1. Period Variations for the Cepheid VZ Cyg

    Science.gov (United States)

    Sirorattanakul, Krittanon; Engle, Scott; Pepper, Joshua; Wells, Mark; Laney, Clifton D.; Rodriguez, Joseph E.; Stassun, Keivan G.

    2017-12-01

    The Cepheid Period-Luminosity law is a key rung on the extragalactic distance ladder. However, numerous Cepheids are known to undergo period variations. Monitoring, refining, and understanding these period variations allows us to better determine the parameters of the Cepheids themselves and of the instability strip in which they reside, and to test models of stellar evolution. VZ Cyg, a classical Cepheid pulsating at ˜4.864 days, has been observed for over 100 years. Combining data from literature observations, the Kilodegree Extremely Little Telescope (KELT) transit survey, and new targeted observations with the Robotically Controlled Telescope (RCT) at Kitt Peak, we find a period change rate of dP/dt = -0.0642 ± 0.0018 s yr-1. However, when only the recent observations are examined, we find a much higher period change rate of dP/dt = -0.0923 ± 0.0110 s yr-1. This higher rate could be due to an apparent long-term (P ≈ 26.5 years) cyclic period variation. The possible interpretations of this single Cepheid’s complex period variations underscore both the need to regularly monitor pulsating variables and the important benefits that photometric surveys such as KELT can have on the field. Further monitoring of this interesting example of Cepheid variability is recommended to confirm and better understand the possible cyclic period variations. Further, Cepheid timing analyses are necessary to fully understand their current behaviors and parameters, as well as their evolutionary histories.

  2. David's Understanding of Functions and Periodicity

    Science.gov (United States)

    Gerson, Hope

    2008-01-01

    This is a study of David, a senior enrolled in a high school precalculus course. David's understandings of functions and periodicity was explored, through clinical interviews and contextualized through classroom observations. Although David's precalculus class was traditional his understanding of periodic functions was unconventional David engaged…

  3. Periodic and secular changes in SS 433

    International Nuclear Information System (INIS)

    Collins, G.W.; Newsom, G.H.

    1983-01-01

    The recent history of SS 433 is reviewed with particular attention being given to the discovery of the periodic phenomena displayed by this object. Several periods ranging from days to months are established as being present in the spectrum of the ''moving'' lines as well as in other aspects of the emission from the object. In addition evidence for secular change in some of the defining parameters of the system is presented. Although these secular changes may eventually prove to be periodic on a rather long time scale, some interpretation of both the periodic and secular phenomena is possible. It is shown that it is possible to interpret all the known periodic phenomena in terms of a processing object responding to the time-varying torques that one would expect in a binary system

  4. Hypokalemic periodic paralysis: Three rare secondary causes

    Directory of Open Access Journals (Sweden)

    Prasanna Eswaradass Venkatesan

    2015-01-01

    Full Text Available Periodic paralysis is a rare neuromuscular disorder, related to a defect in muscle ion channels, characterized by episodes of painless muscle weakness, which may be precipitated by heavy exercise, fasting, or high-carbohydrate meals. Hypokalemic periodic paralysis may be familial (primary or secondary. Here, we report three cases of secondary causes of hypokalemic periodic paralysis. On evaluation, case 1 had distal renal tubular acidosis (RTA due to Sjogren′s syndrome, case 2 had drug induced proximal RTA (Fanconi′s syndrome and case 3 had thyrotoxicosis. Clinician must be aware of causes of secondary PP as recognition and diagnosis can completely prevent further attacks of periodic paralysis. Each of the above case is rare, but completely treatable if diagnosed. Low dose steroids with bicarbonate replacement in case 1, stopping tenofovir in case 2 and carbimazole therapy in case 3 prevented further attacks of periodic paralysis and cardiopulmonary complications.

  5. Periodic-cylinder vesicle with minimal energy

    International Nuclear Information System (INIS)

    Xiao-Hua, Zhou

    2010-01-01

    We give some details about the periodic cylindrical solution found by Zhang and Ou-Yang in [1996 Phys. Rev. E 53 4206] for the general shape equation of vesicle. Three different kinds of periodic cylindrical surfaces and a special closed cylindrical surface are obtained. Using the elliptic functions contained in mathematic, we find that this periodic shape has the minimal total energy for one period when the period–amplitude ratio β ≈ 1.477, and point out that it is a discontinuous deformation between plane and this periodic shape. Our results also are suitable for DNA and multi-walled carbon nanotubes (MWNTs). (cross-disciplinary physics and related areas of science and technology)

  6. Probing the (empirical quantum structure embedded in the periodic table with an effective Bohr model

    Directory of Open Access Journals (Sweden)

    Wellington Nardin Favaro

    2013-01-01

    Full Text Available The atomic shell structure can be observed by inspecting the experimental periodic properties of the Periodic Table. The (quantum shell structure emerges from these properties and in this way quantum mechanics can be explicitly shown considering the (semi-quantitative periodic properties. These periodic properties can be obtained with a simple effective Bohr model. An effective Bohr model with an effective quantum defect (u was considered as a probe in order to show the quantum structure embedded in the Periodic Table. u(Z shows a quasi-smoothed dependence of Z, i.e., u(Z ≈ Z2/5 - 1.

  7. Bifurcation analysis of the logistic map via two periodic impulsive forces

    International Nuclear Information System (INIS)

    Jiang Hai-Bo; Li Tao; Zeng Xiao-Liang; Zhang Li-Ping

    2014-01-01

    The complex dynamics of the logistic map via two periodic impulsive forces is investigated in this paper. The influences of the system parameter and the impulsive forces on the dynamics of the system are studied respectively. With the parameter varying, the system produces the phenomenon such as periodic solutions, chaotic solutions, and chaotic crisis. Furthermore, the system can evolve to chaos by a cascading of period-doubling bifurcations. The Poincaré map of the logistic map via two periodic impulsive forces is constructed and its bifurcation is analyzed. Finally, the Floquet theory is extended to explore the bifurcation mechanism for the periodic solutions of this non-smooth map. (general)

  8. Borrowing constraints, multiple equilibria and monetary policy

    NARCIS (Netherlands)

    Assenza, T.

    2007-01-01

    The appealing feature of Kiyotaki and Moore's Financial Accelerator model (Kiyotaki and Moore, 1997, 2002) is the linkage of asset price changes and borrowing constraints. This framework therefore is the natural vehicle to explore the net worth channel of the monetary transmission mechanism. In the

  9. Periodic sediment shift in migrating ripples influences benthic microbial activity

    Science.gov (United States)

    Zlatanović, Sanja; Fabian, Jenny; Mendoza-Lera, Clara; Woodward, K. Benjamin; Premke, Katrin; Mutz, Michael

    2017-06-01

    Migrating bedforms have high levels of particulate organic matter and high rates of pore water exchange, causing them to be proposed as hot spots of carbon turnover in rivers. Yet, the shifting of sediments and associated mechanical disturbance within migrating bedforms, such as ripples, may stress and abrade microbial communities, reducing their activity. In a microcosm experiment, we replicated the mechanical disturbances caused by the periodic sediment shift within ripples under oligotrophic conditions. We assessed the effects on fungal and bacterial biomass ratio (F:B), microbial community respiration (CR), and bacterial production (BCP) and compared with stable undisturbed sediments. Interactions between periodic mechanical disturbance and sediment-associated particulate organic matter (POM) were tested by enriching sediments collected from migrating ripples with different qualities of POM (fish feces, leaf litter fragments and no addition treatments). F:B and BCP were affected by an interaction between mechanical disturbance and POM quality. Fish feces enriched sediments showed increased F:B and BCP compared to sediments with lower POM quality and responded with a decrease of F:B and BCP to sediment disturbance. In the other POM treatments F:B and BCP were not affected by disturbance. Microbial respiration was however reduced by mechanical disturbance to similar low activity levels regardless of POM qualities added, whereas fish feces enriched sediment showed short temporary boost of CR. With the worldwide proliferation of migrating sand ripples due to massive catchment erosion, suppressed mineralization of POM will increasingly affect stream metabolism, downstream transport of POM and carbon cycling from reach to catchment scale.

  10. Elimination of spiral chaos by periodic force for the Aliev-Panfilov model

    OpenAIRE

    Sakaguchi, Hidetsugu; Fujimoto, Takefumi

    2003-01-01

    Spiral chaos appears in the two dimensional Aliev-Panfilov model. The generation mechanism of the spiral chaos is related to the breathing instability of pulse trains. The spiral chaos can be eliminated by applying periodic force uniformly. The elimination of spiral chaos is most effective, when the frequency of the periodic force is close to that of the breathing motion.

  11. Cyberspatial mechanics.

    Science.gov (United States)

    Bayne, Jay S

    2008-06-01

    In support of a generalization of systems theory, this paper introduces a new approach in modeling complex distributed systems. It offers an analytic framework for describing the behavior of interactive cyberphysical systems (CPSs), which are networked stationary or mobile information systems responsible for the real-time governance of physical processes whose behaviors unfold in cyberspace. The framework is predicated on a cyberspace-time reference model comprising three spatial dimensions plus time. The spatial domains include geospatial, infospatial, and sociospatial references, the latter describing relationships among sovereign enterprises (rational agents) that choose voluntarily to organize and interoperate for individual and mutual benefit through geospatial (physical) and infospatial (logical) transactions. Of particular relevance to CPSs are notions of timeliness and value, particularly as they relate to the real-time governance of physical processes and engagements with other cooperating CPS. Our overarching interest, as with celestial mechanics, is in the formation and evolution of clusters of cyberspatial objects and the federated systems they form.

  12. Umbilical mechanism

    Science.gov (United States)

    Barron, Daniel R. (Inventor); Jasulaitis, Vytas (Inventor); Morrill, Brion F. (Inventor)

    1995-01-01

    Apparatus is described for automatically mating a pair of connectors and protecting them prior to mating, which minimizes weight and uses relatively simple and reliable mechanisms. Lower and upper connectors (24, 26) are held in lower and upper parts (14, 16) of a housing, with the upper connector mounted on a carrier (32) that is motor driven to move down and mate the connectors. A pair of movable members (36, 38) serve as shields, as coarse alignment aids, and as force transmitters. The movable members are pivotally mounted at the bottom of the upper housing, and as the carrier moves down it pivots the members out of the way. The movable members have socket elements (116) that closely receive pin elements (120) on the lower housing part, to coarsely align the connectors and to react mating and unmating forces between the housings. The carrier has a pair of plate portions (60, 62) with slots (64), and the movable members have cam followers engaged with the slot walls, to move the members with precision. The carrier plate-like portions engage follower members (82) that pivot open lower shield parts (44, 46) covering the lower connector, which is mounted on four stacks of Belleville washers (142).

  13. Variable-Period Undulators for Synchrotron Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

    2005-02-22

    A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

  14. Variable-Period Undulators For Synchrotron Radiation

    Science.gov (United States)

    Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

    2005-02-22

    A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high-energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

  15. Optimal glucose management in the perioperative period.

    Science.gov (United States)

    Evans, Charity H; Lee, Jane; Ruhlman, Melissa K

    2015-04-01

    Hyperglycemia is a common finding in surgical patients during the perioperative period. Factors contributing to poor glycemic control include counterregulatory hormones, hepatic insulin resistance, decreased insulin-stimulated glucose uptake, use of dextrose-containing intravenous fluids, and enteral and parenteral nutrition. Hyperglycemia in the perioperative period is associated with increased morbidity, decreased survival, and increased resource utilization. Optimal glucose management in the perioperative period contributes to reduced morbidity and mortality. To readily identify hyperglycemia, blood glucose monitoring should be instituted for all hospitalized patients. Published by Elsevier Inc.

  16. Convectons in periodic and bounded domains

    International Nuclear Information System (INIS)

    Mercader, Isabel; Batiste, Oriol; Alonso, Arantxa; Knobloch, Edgar

    2010-01-01

    Numerical continuation is used to compute spatially localized convection in a binary fluid with no-slip laterally insulating boundary conditions and the results are compared with the corresponding ones for periodic boundary conditions (PBC). The change in the boundary conditions produces a dramatic change in the snaking bifurcation diagram that describes the organization of localized states with PBC: the snaking branches turn continuously into a large amplitude state that resembles periodic convection with defects at the sidewalls. Odd parity convectons are more affected by the boundary conditions since the sidewalls suppress the horizontal pumping action that accompanies these states in spatially periodic domains.

  17. Convectons in periodic and bounded domains

    Energy Technology Data Exchange (ETDEWEB)

    Mercader, Isabel; Batiste, Oriol; Alonso, Arantxa [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, Barcelona (Spain); Knobloch, Edgar [Department of Physics, University of California, Berkeley, CA 94720 (United States)

    2010-04-15

    Numerical continuation is used to compute spatially localized convection in a binary fluid with no-slip laterally insulating boundary conditions and the results are compared with the corresponding ones for periodic boundary conditions (PBC). The change in the boundary conditions produces a dramatic change in the snaking bifurcation diagram that describes the organization of localized states with PBC: the snaking branches turn continuously into a large amplitude state that resembles periodic convection with defects at the sidewalls. Odd parity convectons are more affected by the boundary conditions since the sidewalls suppress the horizontal pumping action that accompanies these states in spatially periodic domains.

  18. Diffraction Theory and Almost Periodic Distributions

    Science.gov (United States)

    Strungaru, Nicolae; Terauds, Venta

    2016-09-01

    We introduce and study the notions of translation bounded tempered distributions, and autocorrelation for a tempered distribution. We further introduce the spaces of weakly, strongly and null weakly almost periodic tempered distributions and show that for weakly almost periodic tempered distributions the Eberlein decomposition holds. For translation bounded measures all these notions coincide with the classical ones. We show that tempered distributions with measure Fourier transform are weakly almost periodic and that for this class, the Eberlein decomposition is exactly the Fourier dual of the Lebesgue decomposition, with the Fourier-Bohr coefficients specifying the pure point part of the Fourier transform. We complete the project by looking at few interesting examples.

  19. Attractors of the periodically forced Rayleigh system

    Directory of Open Access Journals (Sweden)

    Petre Bazavan

    2011-07-01

    Full Text Available The autonomous second order nonlinear ordinary differential equation(ODE introduced in 1883 by Lord Rayleigh, is the equation whichappears to be the closest to the ODE of the harmonic oscillator withdumping.In this paper we present a numerical study of the periodic andchaotic attractors in the dynamical system associated with the generalized Rayleigh equation. Transition between periodic and quasiperiodic motion is also studied. Numerical results describe the system dynamics changes (in particular bifurcations, when the forcing frequency is varied and thus, periodic, quasiperiodic or chaotic behaviour regions are predicted.

  20. Periodicity in Age-Resolved Populations

    Science.gov (United States)

    Esipov, Sergei

    We discuss the interplay between the non-linear diffusion and age-resolved population dynamics. Depending on the age properties of collective migration the system may exhibit continuous joint expansion of all ages or continuous expansion with age segregation. Between these two obvious limiting regimes there is an interesting window of periodic expansion, which has been previously used by us in modeling bacterial colonies of Proteus mirabilis. In order to test whether the age-dependent collective migration leads to periodicity in other systems we performed a Fourier analysis of historical data on ethnic expansions and found multiple co-existing periods of activity.

  1. Periodic solutions of dissipative systems revisited

    Directory of Open Access Journals (Sweden)

    Górniewicz Lech

    2006-01-01

    Full Text Available We reprove in an extremely simple way the classical theorem that time periodic dissipative systems imply the existence of harmonic periodic solutions, in the case of uniqueness. We will also show that, in the lack of uniqueness, the existence of harmonics is implied by uniform dissipativity. The localization of starting points and multiplicity of periodic solutions will be established, under suitable additional assumptions, as well. The arguments are based on the application of various asymptotic fixed point theorems of the Lefschetz and Nielsen type.

  2. Periodic solutions of dissipative systems revisited

    Directory of Open Access Journals (Sweden)

    Lech Górniewicz

    2006-05-01

    Full Text Available We reprove in an extremely simple way the classical theorem that time periodic dissipative systems imply the existence of harmonic periodic solutions, in the case of uniqueness. We will also show that, in the lack of uniqueness, the existence of harmonics is implied by uniform dissipativity. The localization of starting points and multiplicity of periodic solutions will be established, under suitable additional assumptions, as well. The arguments are based on the application of various asymptotic fixed point theorems of the Lefschetz and Nielsen type.

  3. Sensitive periods in human development: evidence from musical training.

    Science.gov (United States)

    Penhune, Virginia B

    2011-10-01

    One of the primary goals of cognitive neuroscience is to understand the interaction between genes, development and specific experience. A particularly fascinating example of this interaction is a sensitive period - a time during development when experience has a differential effect on behavior and the brain. Behavioral and brain imaging studies in musicians have provided suggestive evidence for a possible sensitive period for musical training; showing that musicians who began training early show better task performance and greater changes in auditory and motor regions of the brain. However, these studies have not controlled for likely differences between early- (ET) and late-trained (LT) musicians in the number of years of musical experience. This review presents behavioral work from our laboratory comparing the performance of ET (before age seven) and LT musicians who were matched for years of experience on the ability to tap in synchrony with auditory and visual rhythms. The results demonstrate the existence of a possible sensitive period for musical training that has its greatest impact on measures of sensorimotor integration. Work on motor learning in children and how this might relate to the observed sensitive period effect is also reviewed. These studies are described in the context of what is currently known about sensitive periods in animals and humans; drawing on evidence from anatomy and physiology, studies of deafness, as well as structural and functional neuroimaging studies in trained musicians. The possible mechanisms underlying sensitive periods for musical training are discussed based on current theories describing the influence of both low-level features of sensory experience and higher-level cognitive processing. Copyright © 2011 Elsevier Srl. All rights reserved.

  4. Mechanical Design

    Energy Technology Data Exchange (ETDEWEB)

    Shook, Richard; /Marquette U. /SLAC

    2010-08-25

    The particle beam of the SXR (soft x-ray) beam line in the LCLS (Linac Coherent Light Source) has a high intensity in order to penetrate through samples at the atomic level. However, the intensity is so high that many experiments fail because of severe damage. To correct this issue, attenuators are put into the beam line to reduce this intensity to a level suitable for experimentation. Attenuation is defined as 'the gradual loss in intensity of any flux through a medium' by [1]. It is found that Beryllium and Boron Carbide can survive the intensity of the beam. At very thin films, both of these materials work very well as filters for reducing the beam intensity. Using a total of 12 filters, the first 9 being made of Beryllium and the rest made of Boron Carbide, the beam's energy range of photons can be attenuated between 800 eV and 9000 eV. The design of the filters allows attenuation for different beam intensities so that experiments can obtain different intensities from the beam if desired. The step of attenuation varies, but is relative to the thickness of the filter as a power function of 2. A relationship for this is f(n) = x{sub 0}2{sup n} where n is the step of attenuation desired and x{sub 0} is the initial thickness of the material. To allow for this desired variation, a mechanism must be designed within the test chamber. This is visualized using a 3D computer aided design modeling tool known as Solid Edge.

  5. Mechanical Design

    International Nuclear Information System (INIS)

    2010-01-01

    The particle beam of the SXR (soft x-ray) beam line in the LCLS (Linac Coherent Light Source) has a high intensity in order to penetrate through samples at the atomic level. However, the intensity is so high that many experiments fail because of severe damage. To correct this issue, attenuators are put into the beam line to reduce this intensity to a level suitable for experimentation. Attenuation is defined as 'the gradual loss in intensity of any flux through a medium' by (1). It is found that Beryllium and Boron Carbide can survive the intensity of the beam. At very thin films, both of these materials work very well as filters for reducing the beam intensity. Using a total of 12 filters, the first 9 being made of Beryllium and the rest made of Boron Carbide, the beam's energy range of photons can be attenuated between 800 eV and 9000 eV. The design of the filters allows attenuation for different beam intensities so that experiments can obtain different intensities from the beam if desired. The step of attenuation varies, but is relative to the thickness of the filter as a power function of 2. A relationship for this is f(n) = x 0 2 n where n is the step of attenuation desired and x 0 is the initial thickness of the material. To allow for this desired variation, a mechanism must be designed within the test chamber. This is visualized using a 3D computer aided design modeling tool known as Solid Edge.

  6. 77 FR 73452 - Grace Period Study

    Science.gov (United States)

    2012-12-10

    ... survey may be distributed in waves for convenience. The Grace Period Study survey will be an electronic... information that is used for sampling purposes will be maintained in a separate file from the quantitative...

  7. Time-Varying Periodicity in Intraday Volatility

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

    We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

  8. Multi-Period Trading via Convex Optimization

    DEFF Research Database (Denmark)

    Boyd, Stephen; Busseti, Enzo; Diamond, Steve

    2017-01-01

    We consider a basic model of multi-period trading, which can be used to evaluate the performance of a trading strategy. We describe a framework for single-period optimization, where the trades in each period are found by solving a convex optimization problem that trades off expected return, risk......, transaction cost and holding cost such as the borrowing cost for shorting assets. We then describe a multi-period version of the trading method, where optimization is used to plan a sequence of trades, with only the first one executed, using estimates of future quantities that are unknown when the trades....... In this paper, we do not address a critical component in a trading algorithm, the predictions or forecasts of future quantities. The methods we describe in this paper can be thought of as good ways to exploit predictions, no matter how they are made. We have also developed a companion open-source software...

  9. Optimization on replacement period of plant equipment

    International Nuclear Information System (INIS)

    Kasai, Masao; Asano, Hiromi

    2002-01-01

    Optimization of the replacement period of plant equipment is one of the main items to rationalize the activities on plant maintenance. There are several models to replace the equipment and the formulations for optimizing the replacement period are different among these models. In this study, we calculated the optimum replacement periods for some equipment parts based on the replacement models and found that the optimum solutions are not so largely differ from the replacement models as far as the replacement period is not so large. So we will be able to use the most usable model especially in the early phase of rationalization on plant maintenance, since there are large uncertainties in data for optimization. (author)

  10. Early and Periodic Screening, Diagnosis and Treatment

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Early and Periodic Screening, Diagnostic and Treatment (EPSDT) benefit provides comprehensive and preventive health care services for children under age 21 who...

  11. 12 CFR 219.24 - Retention period.

    Science.gov (United States)

    2010-01-01

    ... PROVIDING FINANCIAL RECORDS; RECORDKEEPING REQUIREMENTS FOR CERTAIN FINANCIAL RECORDS (REGULATION S... period of time, taking into consideration the nature of the record and the amount of time that has...

  12. The period-luminosity relation for Cepheids

    International Nuclear Information System (INIS)

    Brodie, J.P.

    1980-01-01

    Numerical simulations of the empirical determination of the period-luminosity-colour relation for classical Cepheids are presented. In this study the quantitative effects of random errors, reddening, sample size and the presence of both colour and period cut-offs (imposed by the finite extent of the instability strip) on the observational redetermination of the original relation are evaluated. Both random errors in the photometry and correlated errors in the reddening corrections are shown to have systematic effects. Especially sensitive to these errors is the colour coefficient in the period-luminosity-colour relation, where the ratio of the error to the width of the instability strip is the determining factor. With present observations only broad confidence limits can be placed on present knowledge of the intrinsic period-luminosity-colour relation and/or its variations from galaxy to galaxy. (author)

  13. Genetics Home Reference: hypokalemic periodic paralysis

    Science.gov (United States)

    ... M, Franques J, Bendahhou S, Lory P, Hainque B, Fournier E, Nicole S, Fontaine B. Hypokalemic Periodic Paralysis. 2002 ... related congenital muscular dystrophy Melorheostosis Rhabdoid tumor predisposition syndrome All New & Updated Pages Reviewed : October 2017 Published : ...

  14. The ACM Periodical Bank: A Retrospective View.

    Science.gov (United States)

    Clarke, Jack A.

    1980-01-01

    Evaluates a cooperative venture in interlibrary lending of periodicals planned and executed by ten midwestern colleges. The study traces the consortium's history from 1967 to the present, describing successes and problems. (RAA)

  15. Ecological periodic tables: In principle and practice

    Science.gov (United States)

    The chemical periodic table, the Linnaean system of classification and the Hertzsprung-Russell diagram are iconic information organizing structure in chemistry, biology and astronomy, respectively, because they are simple, exceptionally useful and they foster the expansion of sci...

  16. Galactic Dark Matter and Terrestrial Periodicities

    National Research Council Canada - National Science Library

    Clube, S

    1998-01-01

    .... The Earth may thus be regarded as a probe of the disc environment; and to account for the periodicity, the Galactic disc is required to have a substantial dark matter component ( approx .15 molar mass/cu pc...

  17. Periodical test program in depth revision

    International Nuclear Information System (INIS)

    Feltin, C.; Zermizoglou, R.

    1987-11-01

    Inspection visits made to different sites during 1980 and 1981 evidenced the need to extend and define more precisely the periodical tests performed on safety related systems; thus Electricite de France was requested by the Safety Authorities to re-examine the periodical test program for all safety related systems. This paper presents the methodology adopted by Electricite de France in order to perform an exhaustive analysis of the periodical test program for the 900 and 1300 MWe plants, and the organization set up at the IPSN at one hand and Electricite de France on the other hand for the purpose of elaborating a periodical test program which would be ratified by the Safety Authorities

  18. Toward an Organic Chemist's Periodic Table.

    Science.gov (United States)

    Hall, H. K., Jr.

    1980-01-01

    An analogy between electron transfer reactions of the elements and those of organic molecules is offered. Examples of organic electron transfer reactions are presented. The rationale of constructing an organic chemists' periodic table is also discussed. (HM)

  19. Theodore William Richards and the Periodic Table

    Science.gov (United States)

    Conant, James B.

    1970-01-01

    Discusses the contribution of Theodore Richards to the accurate determination of atomic weights of copper and other elements; his major contribution was to the building of the definitive periodic table of the elements. (BR)

  20. Spectral properties of almost-periodic Hamiltonians

    International Nuclear Information System (INIS)

    Lima, R.

    1983-12-01

    We give a description of some spectral properties of almost-periodic hamiltonians. We put the stress on some particular points of the proofs of the existence of absolutely continuous or pure point spectrum [fr

  1. Astrobee Periodic Technical Review (PTR) Delta 3

    Science.gov (United States)

    Provencher, Christopher; Smith, Marion F.; Smith, Ernest Everett; Bualat, Maria Gabriele; Barlow, Jonathan Spencer

    2017-01-01

    Astrobee is a free flying robot for the inside of the International Space Station (ISS). The Periodic Technical Review (PTR) delta 3 is the final design review of the system presented to stakeholders.

  2. Periodic words connected with the Fibonacci words

    Directory of Open Access Journals (Sweden)

    G. M. Barabash

    2016-06-01

    Full Text Available In this paper we introduce two families of periodic words (FLP-words of type 1 and FLP-words of type 2 that are connected with the Fibonacci words and investigated their properties.

  3. A Bayesian Approach to Period Searching in Solar Coronal Loops

    Energy Technology Data Exchange (ETDEWEB)

    Scherrer, Bryan; McKenzie, David [Montana State University, P.O. Box 173840 Bozeman, MT 59717-3840 (United States)

    2017-03-01

    We have applied a Bayesian generalized Lomb–Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each light curve of the data. Both the amplitudes and noise are taken as free parameters. It is argued that this procedure should be used alongside Fourier and wavelet analyses to more accurately extract periodic intensity modulations in coronal loops. The data analyzed are from XRT Observation Program 129C: “MHD Wave Heating (Thin Filters),” which occurred during 2006 November 13 and focused on active region 10293, which included coronal loops. The first data set spans approximately 10 min with an average cadence of 2 s, 2″ per pixel resolution, and used the Al-mesh analysis filter. The second data set spans approximately 4 min with a 3 s average cadence, 1″ per pixel resolution, and used the Al-poly analysis filter. The final data set spans approximately 22 min at a 6 s average cadence, and used the Al-poly analysis filter. In total, 55 periods of sinusoidal coronal loop oscillations between 5.5 and 59.6 s are discussed, supporting proposals in the literature that resonant absorption of magnetic waves is a viable mechanism for depositing energy in the corona.

  4. Quasi-periodic latitudinal shift of Saturn's main auroral emission

    Science.gov (United States)

    Roussos, E.; Palmaerts, B.; Grodent, D. C.; Radioti, K.; Krupp, N.; Yao, Z.

    2017-12-01

    The main component of the ultraviolet auroral emissions at Saturn consists in a ring of emission around each pole of the planet. This main ring of emission has been revealed to oscillate by a few degrees in the prenoon-premidnight direction with a period of 10.8h. This auroral oscillation is thought to be induced by a rotating external magnetospheric current system associated with the planetary period oscillations. Here we report, by means of auroral imaging sequences obtained with the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft, the first direct observation of an additional motion of the main emission superimposed to this oscillation. The whole main emission ring exhibits step-like displacements in latitude mainly towards dayside, decoupled from the 10.8h oscillation. These latitude shifts recur around every hour, which is a typical short periodicity at Saturn previously identified in the aurora intensity, in the charged particle fluxes and in the magnetic field. This unique observation directly demonstrates what has been inferred from past in-situ and remote measurements: the 1-hour periodicities reveal a global and fundamental magnetospheric oscillation mode that acts independently of the local magnetospheric conditions. However, the magnetospheric mechanism responsible for these 1-hour auroral shifts is still unknown. It is possible that Alfvén waves inducing hourly magnetic fluctuations might also modify the place where the field-aligned electrons precipitate in the ionosphere and produce the main emission.

  5. Prognosis following cancer surgery during holiday periods.

    Science.gov (United States)

    Lagergren, Jesper; Mattsson, Fredrik; Lagergren, Pernilla

    2017-11-15

    Surgery is the mainstay curative treatment in most cancer. We aimed to test the new hypothesis that cancer surgery performed during holiday periods is associated with worse long-term prognosis than for non-holiday periods. This nationwide Swedish population-based cohort study included 228,927 patients during 1997-2014 who underwent elective resectional surgery for a cancer where the annual number of resections was over 100. The 16 eligible cancer sites were grouped into 10 cancer groups. The exposure, holiday periods, was classified as wide (14-weeks) or narrow (7-weeks). Surgery conducted inside versus outside holiday periods was compared regarding overall disease-specific (main outcome) and overall all-cause (secondary outcome) mortality. Cox regression provided hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, sex, comorbidity, hospital volume, calendar period and tumor stage. Surgery conducted during wide and narrow holiday periods were associated with increased HRs of disease-specific mortality for cancer of the breast (HR 1.08, 95% CI 1.03-1.13 and HR 1.06, 95% CI 1.01-1.12) and possibly of cancer of the liver-pancreas-bile ducts (HR 1.09, 95% CI 0.99-1.20 and HR 1.12, 95% CI 0.99-1.26). Sub-groups with cancer of the colon-rectum, head-and-neck, prostate, kidney-urine bladder and thyroid also experienced statistically significantly worse prognosis following surgery conducted during holiday periods. No influence of surgery during holiday was detected for cancer of the esophagus-stomach, lung or ovary-uterus. All-cause HRs were similar to the disease-specific HRs. The prognosis following cancer surgery might not be fully maintained during holiday periods for all cancer sites. © 2017 UICC.

  6. Entanglement of periodic anisotropic XY chains

    International Nuclear Information System (INIS)

    Zhang Lifa; Tong Peiqing

    2005-01-01

    By using the concept of concurrence, the entanglement of periodic anisotropic XY chains in a transverse field is studied numerically. It is found that the derivatives ∂ λ C(1) of nearest-neighbour concurrence diverge at quantum critical points. By proper scaling, we found that all the derivatives ∂ λ C(1) for periodic XY chains in the vicinity of quantum critical points have the same behaviours as that of a uniform chain

  7. Coupled mode theory of periodic waveguides arrays

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Chigrin, Dmitry N.

    We apply the scalar coupled mode theory to the case of waveguides array consisting om two periodic waveguides. One of the waveguides is arbitrary shifted along another. A longitudinal shift acts as a parameter in the coupled mode theory. The proposed theory explains peculiarities of modes dispers...... dispersion and transmission in coupled periodic waveguides systems. Analytical results are compared with the numerical ones obtained by the plane wave expansion and FDTD methods....

  8. IUPAC Periodic Table of the Isotopes

    Science.gov (United States)

    Holden, N.E.; Coplen, T.B.; Böhlke, J.K.; Wieser, M.E.; Singleton, G.; Walczyk, T.; Yoneda, S.; Mahaffy, P.G.; Tarbox, L.V.

    2011-01-01

    For almost 150 years, the Periodic Table of the Elements has served as a guide to the world of elements by highlighting similarities and differences in atomic structure and chemical properties. To introduce students, teachers, and society to the existence and importance of isotopes of the chemical elements, an IUPAC Periodic Table of the Isotopes (IPTI) has been prepared and can be found as a supplement to this issue.

  9. Periodicity and Immortality in Reversible Computing

    OpenAIRE

    Kari , Jarkko; Ollinger , Nicolas

    2008-01-01

    Additional material available on the web at http://www.lif.univ-mrs.fr/~nollinge/rec/gnirut/; We investigate the decidability of the periodicity and the immortality problems in three models of reversible computation: reversible counter machines, reversible Turing machines and reversible one-dimensional cellular automata. Immortality and periodicity are properties that describe the behavior of the model starting from arbitrary initial configurations: immortality is the property of having at le...

  10. Specific features of elite bodybuilders’ training process in competition period

    Directory of Open Access Journals (Sweden)

    A.A. Tihorsky

    2016-12-01

    Full Text Available Purpose: To substantiate methodic of training process construction for elite bodybuilders in competition period with usage of different training methods. Material: elite bodybuilders - members of combined team of Ukraine (n=16 participated in the research. Results: we presented comparative characteristic of the most often used bodybuilding training methodic. Besides, optimal training methodic in competition period was worked out and substantiated. Such methodic permits to improve body proportions at the account of fat layer reduction. By the data of Harvard step-test the sportsmen improved organism’s functional potentials by 6%. Conclusions: the offered methodic noticeably reduces probability of functional unfavorable states (over-training, overloading, traumas. The methodic permits to achieve the required sport form without over-tension adaptation-compensatory mechanisms and acquire maximal muscular relief; improve proportions with minimal losses of muscles’ volume.

  11. PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

    International Nuclear Information System (INIS)

    Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

    2015-01-01

    Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods

  12. Interference pattern period measurement at picometer level

    Science.gov (United States)

    Xiang, Xiansong; Wei, Chunlong; Jia, Wei; Zhou, Changhe; Li, Minkang; Lu, Yancong

    2016-10-01

    To produce large scale gratings by Scanning Beam Interference Lithography (SBIL), a light spot containing grating pattern is generated by two beams interfering, and a scanning stage is used to drive the substrate moving under the light spot. In order to locate the stage at the proper exposure positions, the period of the Interference pattern must be measured accurately. We developed a set of process to obtain the period value of two interfering beams at picometer level. The process includes data acquisition and data analysis. The data is received from a photodiode and a laser interferometer with sub-nanometer resolution. Data analysis differs from conventional analyzing methods like counting wave peaks or using Fourier transform to get the signal period, after a preprocess of filtering and envelope removing, the mean square error is calculated between the received signal and ideal sinusoid waves to find the best-fit frequency, thus an accuracy period value is acquired, this method has a low sensitivity to amplitude noise and a high resolution of frequency. With 405nm laser beams interfering, a pattern period value around 562nm is acquired by employing this process, fitting diagram of the result shows the accuracy of the period value reaches picometer level, which is much higher than the results of conventional methods.

  13. Physical explanation of the periodic table.

    Science.gov (United States)

    Ostrovsky, V N

    2003-05-01

    The Periodic Table of the elements, the most important generalization in chemistry, is often considered as a representative special case in the study of the relation between chemistry and physics. Its quantum interpretation was initiated, but not completed, by Niels Bohr. In this paper, post-Bohr conceptual developments are discussed from historical and epistemological points of view. The difference between high-precision numerical calculations for individual atoms and the theory of the periodic system as a whole is emphasized. Periodic laws met in Nature are not restricted to the chemical Periodic Table. A comparative study of these laws makes it possible to single out essential features that define the particular pattern of periodicity. It is shown that the periodic system of neutral ground state atoms now has a firm nonempirical quantum-theoretical basis. Alternative approaches, based on group theory and other mathematical schemes, are briefly discussed. It is argued that, while quantum theory is capable of fully accurate calculations for relatively simple atoms or molecular objects, the complexity of polyatomic molecules and chemical reactions guarantees the flourishing of chemistry as a separate scientific discipline.

  14. Estimates on the minimal period for periodic solutions of nonlinear second order Hamiltonian systems

    International Nuclear Information System (INIS)

    Yiming Long.

    1994-11-01

    In this paper, we prove a sharper estimate on the minimal period for periodic solutions of autonomous second order Hamiltonian systems under precisely Rabinowitz' superquadratic condition. (author). 20 refs, 1 fig

  15. Bounded and Periodic Solutions of Semilinear Impulsive Periodic System on Banach Spaces

    Directory of Open Access Journals (Sweden)

    Wei W

    2008-01-01

    Full Text Available Abstract A class of semilinear impulsive periodic system on Banach spaces is considered. First, we introduce the -periodic PC-mild solution of semilinear impulsive periodic system. By virtue of Gronwall lemma with impulse, the estimate on the PC-mild solutions is derived. The continuity and compactness of the new constructed Poincaré operator determined by impulsive evolution operator corresponding to homogenous linear impulsive periodic system are shown. This allows us to apply Horn's fixed-point theorem to prove the existence of -periodic PC-mild solutions when PC-mild solutions are ultimate bounded. This extends the study on periodic solutions of periodic system without impulse to periodic system with impulse on general Banach spaces. At last, an example is given for demonstration.

  16. Long Period Source Characteristics of Great Earthquakes: diagnosing complexity

    Science.gov (United States)

    Rivera, L. A.; Kanamori, H.

    2013-12-01

    With the commonly used centroid moment tensor inversions, just one number represents the long period size of the event, the seismic moment Mo (or corresponding Mw). However, several recent studies have clearly demonstrated that this is not satisfactory, at least for some earthquakes. For example, for the 2004 Sumatra-Andaman Is. Earthquake, the amplitudes of long-period normal modes indicated that the effective seismic moment increases from 4.0x1022 to 7.1x1022 N-m as the period increases from 300 to 1000 sec. For the 2009 Samoa Is. earthquake (Mw=8.1), the moment tensor was found to be strongly dependent on frequency because the source of this earthquake consists of at least 2 distinct events with very different mechanisms. It is possible that other large and great earthquakes may have similar complex characteristics, but with the standard moment tensor inversion with a single frequency band, we may not notice this easily. Here we investigate the possible frequency dependence of the moment tensor of large earthquakes by performing W phase inversions using teleseismic data and equally spaced narrow overlapping frequency bands. We investigate frequencies from 2.6 to 3.8 mHz. We focus on the variation with frequency of the scalar moment, the amount of non double couple and the focal mechanism. We apply this technique to 30 major events in the period 1994-2013 and use the results to detect source complexity. We class them in three groups according to the variability of the source parameters with frequency: Simple, Complex and Intermediate events and we discuss the correlation of the result of this approach with independent observations of source complexity.

  17. Physically-insightful equivalent circuit models for electromagnetic periodic structures

    Science.gov (United States)

    Mesa, F.; Rodríguez-Berral, R.; Medina, F.

    2018-02-01

    In this presentation it will be discussed how to obtain analytical or quasi-analytical equivalent circuits to deal with periodic structures such as frequency selective surfaces and/or metasurfaces. Both the topology and the values of the involved elements of these circuits are obtained from a basic rationale to solve the corresponding integral equation. This procedure, besides providing a very efficient analysis/design tool, allows for a good physical insight into the operating mechanisms of the structure in contrast with the almost blind numerical scheme of commercial simulators.

  18. Study for elevator cage position during the braking period

    Science.gov (United States)

    Ungureanu, M.; Crăciun, I.; Bănică, M.; Dăscălescu, A.

    2016-08-01

    An important problem in order to study an elevator cage position for its braking period is to establish a correlation between the studies in the fields of mechanics and electric. The classical approaches to establish the elevator kinematic parameters are position, velocity and acceleration, but the last studies performed in order to determine the positioning performed by introducing supplementary another parameter - the jerk- which is derived with respect to time of acceleration. Thus we get a precise method for cage motion control for third-order trajectory planning.

  19. Mathematical phenomenology of neural stimulation by periodic fields.

    Science.gov (United States)

    Balduzzo, M; Milone, F Ferro; Minelli, T A; Pittaro-Cadore, I; Turicchia, L

    2003-04-01

    Neuron synchronization has been hypothesized as the basic mechanism leading neurological phenomena like low electroencephalographic rhythm dimension or high coherence. Cognitive processes, such as associative memory, can also be explained in terms of neuron synchronization. Inspired by the analysis of an experiment on cortex periodic photostimulation, in resonance conditions, a simple network of integrate and fire (i and f) neurons, has been used to simulate cognitive perturbations by oscillatory and pulsate stimulation of the central nervous system (CNS). In view of realistic simulations of transcranial magnetic stimulation (TMS) phenomena, a discrete extension of the FitzHug-Nagumo nervous fiber model, endowed with regenerative nodes, has been developed too.

  20. Convergence acceleration of quasi-periodic and quasi-periodic-rational interpolations by polynomial corrections

    OpenAIRE

    Lusine Poghosyan

    2014-01-01

    The paper considers convergence acceleration of the quasi-periodic and the quasi-periodic-rational interpolations by application of polynomial corrections. We investigate convergence of the resultant quasi-periodic-polynomial and quasi-periodic-rational-polynomial interpolations and derive exact constants of the main terms of asymptotic errors in the regions away from the endpoints. Results of numerical experiments clarify behavior of the corresponding interpolations for moderate number of in...

  1. Parametric instability in the Watt governor with periodic loading

    International Nuclear Information System (INIS)

    Bhattacharjee, Shayak; Kumar, Krishna

    2014-01-01

    In this work we examine a potential source of instability in the Watt governor, which can occur when the governor is subjected to periodic variation of the load torque. Floquet analysis is used to obtain the condition for existence of the unstable solutions, and results are obtained which supplement the usual Maxwell–Vyshnegradskii conditions for governor stability. Pedagogically, this paper is relevant for senior undergraduate students. It presents a detailed yet simple exposition of classical Floquet theory, a subject often ignored in undergraduate education even though the related concept of Bloch's theorem is popular in quantum mechanics courses. At the same time, it touches on certain practical engineering applications of physical concepts, with its discussion on mechanical governors. (paper)

  2. Periodic Table Target: A Game that Introduces the Biological Significance of Chemical Element Periodicity

    Science.gov (United States)

    Sevcik, Richard S.; McGinty, Ragan L.; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    Periodic Table Target, a game for middle school or high school students, familiarizes students with the form of the periodic table and the biological significance of different elements. The Periodic Table Target game board is constructed as a class project, and the game is played to reinforce the content. Students are assigned several elements…

  3. Period, Place and Mental Space: Using Historical Scholarship to Develop Year 7 Pupils' Sense of Period

    Science.gov (United States)

    Smith, Dan

    2014-01-01

    What is a sense of period? And how can pupils' sense of period be developed? Questions such as these have troubled history teachers for many years, often revolving around debates over the role played by empathy and imagination in coming to know a period on its own terms. Rather than adopt a comparative approach, Dan Smiths decided in his teaching…

  4. mPeriod2 Brdm1 and other single Period mutant mice have normal food anticipatory activity.

    Science.gov (United States)

    Pendergast, Julie S; Wendroth, Robert H; Stenner, Rio C; Keil, Charles D; Yamazaki, Shin

    2017-11-14

    Animals anticipate the timing of food availability via the food-entrainable oscillator (FEO). The anatomical location and timekeeping mechanism of the FEO are unknown. Several studies showed the circadian gene, Period 2, is critical for FEO timekeeping. However, other studies concluded that canonical circadian genes are not essential for FEO timekeeping. In this study, we re-examined the effects of the Per2 Brdm1 mutation on food entrainment using methods that have revealed robust food anticipatory activity in other mutant lines. We examined food anticipatory activity, which is the output of the FEO, in single Period mutant mice. Single Per1, Per2, and Per3 mutant mice had robust food anticipatory activity during restricted feeding. In addition, we found that two different lines of Per2 mutant mice (ldc and Brdm1) anticipated restricted food availability. To determine if FEO timekeeping persisted in the absence of the food cue, we assessed activity during fasting. Food anticipatory (wheel-running) activity in all Period mutant mice was also robust during food deprivation. Together, our studies demonstrate that the Period genes are not necessary for the expression of food anticipatory activity.

  5. Charged particle periodicity in the Saturnian magnetosphere

    International Nuclear Information System (INIS)

    Carbary, J.F.; Krimigis, S.M.

    1982-01-01

    The low energy charged particles (LECP) experiments on the Voyager 1 and 2 spacecraft performed measurements of electrons (approx.22 keV to approx.20 MeV) and ions (approx.28 keV to approx.150 MeV) during the Saturn encounters in 1980 and 1981. Count rate ratios of two of the low energy electron (22 to 35 keV and 183 to 500 keV) and ion (43 to 80 keV and 137 to 215 keV) channels exhibit an approximation 10 hour periodicity in the outer Saturnian magnetosphere beyond the orbit of Titan. Electron ratios vary from approx.50 to approx.300; ion ratios vary from approx.3 to approx.20. Similar but less pronounced periodicities are observed for higher and lower energy electron and ion spectral indices. Three complete cycles were observed during the Voyager 2 outbound portion of the encounter from which were determined an electron ratio period of 10/sup h/21/sup m/ +- 48/sup m/ and an ion ratio period of 9/sup h/49/sup m/ +- 59/sup m/. Using Saturn Kilometric Radiation (SKR) and Saturn Electrostatic Discharge (SED) periods, extrapolation backward from Voyager 2 to Voyager 1 suggests that the periodicities are Saturnian rather than Jovian in nature, and that they persist in phase for time intervals at least as long as 287 days. Ratio minima, or spectral hardenings, occur in the same hemisphere as do auroral brightenings, SKR activity, and spoke enhanement. We interpret the observations as prima facie evidence of an asymmetry in the Saturian magnetic field and the root cause of the observed SKR periodicity

  6. Methodic of practical study teaching on subject 'Characteristic mechanical oscillations'

    International Nuclear Information System (INIS)

    Tenchurina, A.R.

    2006-01-01

    In this article the methodic of the undertaking the practical lesson for subject 'the own mechanical vibrations' is considered and offered the algorithm of the problem decision the finding of the vibration period for the different mechanical systems. (author)

  7. Reward acts as a signal to control delay-period activity in delayed-response tasks.

    Science.gov (United States)

    Ichihara-Takeda, Satoe; Takeda, Kazuyoshi; Funahashi, Shintaro

    2010-03-31

    Prefrontal delay-period activity represents a neural mechanism for the active maintenance of information and needs to be controlled by some signal to appropriately operate working memory. To examine whether reward-delivery acts as this signal, the effects of delay-period activity in response to unexpected reward-delivery were examined by analyzing single-neuron activity recorded in the primate dorsolateral prefrontal cortex. Among neurons that showed delay-period activity, 34% showed inhibition of this activity in response to unexpected reward-delivery. The delay-period activity of these neurons was affected by the expectation of reward-delivery. The strength of the reward signal in controlling the delay-period activity is related to the strength of the effect of reward information on the delay-period activity. These results indicate that reward-delivery acts as a signal to control delay-period activity.

  8. Muscular power, neuromuscular activation, and performance in shot put athletes at preseason and at competition period.

    Science.gov (United States)

    Kyriazis, Thomas A; Terzis, Gerasimos; Boudolos, Konstantinos; Georgiadis, Georgios

    2009-09-01

    The aim of this study was to investigate changes in shot put performance, muscular power, and neuromuscular activation of the lower extremities, between the preseason and the competition period, in skilled shot put athletes using the rotational technique. Shot put performance was assessed at the start of the pre-season period as well as after 12 weeks, at the competition period, in nine shot putters. Electromyographic (EMG) activity of the right vastus lateralis muscle was recorded during all shot put trials. Maximum squat strength (1RM) and mechanical parameters during the countermovement jump (CMJ) on a force platform were also determined at pre-season and at competition period. Shot put performance increased 4.7% (p phase was increased significantly (p training period. Shot put performance was significantly related with muscular power and takeoff velocity during the CMJ, at competition period (r = 0.66, p competition period.

  9. The period-age relation for cepheids

    International Nuclear Information System (INIS)

    Efremov, Yu.N.

    1978-01-01

    The list of 119 cepheid-members of 55 clusters and associations of the Magellanic Clouds, the Galaxy, and M31 is given. The period-age relation is found from the data on 64 cepheids in 29 clusters for which the age determinations are available, the ages of extragalactic clusters were determined mainly from their integral colours. The U-B colours are found to be of much better age parameters than the B-V ones. The composite period-age relation agrees well with the theoretical one. The observed dispersion of the period-age relation leads to an estimate of the age dispersion about 1x10 7 years in the associations. Some peculiarities of the cepheids with the shortest periods amongst others in the same clusters are probably explained if they are overtone pulsators. The period-age relation may be used for an investigation of the recent history of star formation in the galaxies. This relation allows to determine the age gradient across the spiral arm in M31 which is in agreement with the density wave theory predictions. The distribution of cepheids in our Galaxy and neighbouring galaxies is consistent with the conception of star formation lasting for some dozen million years in cells with a dimension of some hundreds of parsecs

  10. Periodic subsystem density-functional theory

    International Nuclear Information System (INIS)

    Genova, Alessandro; Pavanello, Michele; Ceresoli, Davide

    2014-01-01

    By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn–Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn–Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed

  11. Periodic subsystem density-functional theory

    Science.gov (United States)

    Genova, Alessandro; Ceresoli, Davide; Pavanello, Michele

    2014-11-01

    By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn-Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn-Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.

  12. Multiphase averaging of periodic soliton equations

    International Nuclear Information System (INIS)

    Forest, M.G.

    1979-01-01

    The multiphase averaging of periodic soliton equations is considered. Particular attention is given to the periodic sine-Gordon and Korteweg-deVries (KdV) equations. The periodic sine-Gordon equation and its associated inverse spectral theory are analyzed, including a discussion of the spectral representations of exact, N-phase sine-Gordon solutions. The emphasis is on physical characteristics of the periodic waves, with a motivation from the well-known whole-line solitons. A canonical Hamiltonian approach for the modulational theory of N-phase waves is prescribed. A concrete illustration of this averaging method is provided with the periodic sine-Gordon equation; explicit averaging results are given only for the N = 1 case, laying a foundation for a more thorough treatment of the general N-phase problem. For the KdV equation, very general results are given for multiphase averaging of the N-phase waves. The single-phase results of Whitham are extended to general N phases, and more importantly, an invariant representation in terms of Abelian differentials on a Riemann surface is provided. Several consequences of this invariant representation are deduced, including strong evidence for the Hamiltonian structure of N-phase modulational equations

  13. Medicine in Balkans during the Roman Period.

    Science.gov (United States)

    Baykan, Daniş

    2017-08-04

    The aim of this study is to investigate the archaeological finds to enlighten the medical methods of treatments and operations applied in Balkans during Roman Period. Some independent local and regional find groups, taken from existing publications will be grouped together and a holistic point-of-view will be taken against medicine in Balkan Geography during Roman Period. Due to basic differences it contained, the data before Roman Period are excluded. Most of Greece and Aegean Islands are also excluded since the topic selected is "Medicine of Roman Period." Greece and Aegean Islands should be evaluated in another study in connection with West Anatolia which is closer than the Balkan Geography in terms of social relations. The spread of medical tools in Balkans during Roman Period is concentrated around military garrisons, and in settlements built around military pathways, and in settlements containing an amphitheater associated with gladiators. This spread is verified by the studies on Bulgaria in general. The data is also compatible with the assertion suggesting that the amount of application of pharmaceutical treatment increases when one moves away from the military centres.

  14. The Discrete Beverton-Holt Model with Periodic Harvesting in a Periodically Fluctuating Environment

    Directory of Open Access Journals (Sweden)

    Ziyad AlSharawi

    2010-01-01

    Full Text Available We investigate the effect of constant and periodic harvesting on the Beverton-Holt model in a periodically fluctuating environment. We show that in a periodically fluctuating environment, periodic harvesting gives a better maximum sustainable yield compared to constant harvesting. However, if one can also fix the environment, then constant harvesting in a constant environment can be a better option, especially for sufficiently large initial populations. Also, we investigate the combinatorial structure of the periodic sequence of carrying capacities and its effect on the maximum sustainable yield. Finally, we leave some questions worth further investigations.

  15. On complex periodic motions and bifurcations in a periodically forced, damped, hardening Duffing oscillator

    International Nuclear Information System (INIS)

    Guo, Yu; Luo, Albert C.J.

    2015-01-01

    In this paper, analytically predicted are complex periodic motions in the periodically forced, damped, hardening Duffing oscillator through discrete implicit maps of the corresponding differential equations. Bifurcation trees of periodic motions to chaos in such a hardening Duffing oscillator are obtained. The stability and bifurcation analysis of periodic motion in the bifurcation trees is carried out by eigenvalue analysis. The solutions of all discrete nodes of periodic motions are computed by the mapping structures of discrete implicit mapping. The frequency-amplitude characteristics of periodic motions are computed that are based on the discrete Fourier series. Thus, the bifurcation trees of periodic motions are also presented through frequency-amplitude curves. Finally, based on the analytical predictions, the initial conditions of periodic motions are selected, and numerical simulations of periodic motions are carried out for comparison of numerical and analytical predictions. The harmonic amplitude spectrums are also given for the approximate analytical expressions of periodic motions, which can also be used for comparison with experimental measurement. This study will give a better understanding of complex periodic motions in the hardening Duffing oscillator.

  16. Policy Uncertainty, Investment and Commitment Periods

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Today's investment decisions in key sectors such as energy, forestry or transport have significant impacts on the levels of greenhouse gas (GHG) emissions over the coming decades. Given the economic and environmental long-term implications of capital investment and retirement, a climate mitigation regime should aim to encourage capital investment in climate-friendly technologies. Many factors affect technology choice and the timing of investment, including investor expectations about future prices and policies. Recent international discussions have focused on the importance of providing more certainty about future climate policy stringency. The design of commitment periods can play a role in creating this environment. This paper assesses how the length of commitment periods influences policy uncertainty and investment decisions. In particular, the paper analyses the relationship between commitment period length and near term investment decisions in climate friendly technology.

  17. Effective propagation in a perturbed periodic structure

    Science.gov (United States)

    Maurel, Agnès; Pagneux, Vincent

    2008-08-01

    In a recent paper [D. Torrent, A. Hakansson, F. Cervera, and J. Sánchez-Dehesa, Phys. Rev. Lett. 96, 204302 (2006)] inspected the effective parameters of a cluster containing an ensemble of scatterers with a periodic or a weakly disordered arrangement. A small amount of disorder is shown to have a small influence on the characteristics of the acoustic wave propagation with respect to the periodic case. In this Brief Report, we inspect further the effect of a deviation in the scatterer distribution from the periodic distribution. The quasicrystalline approximation is shown to be an efficient tool to quantify this effect. An analytical formula for the effective wave number is obtained in one-dimensional acoustic medium and is compared with the Berryman result in the low-frequency limit. Direct numerical calculations show a good agreement with the analytical predictions.

  18. Effective propagation in a perturbed periodic structure

    International Nuclear Information System (INIS)

    Maurel, Agnes; Pagneux, Vincent

    2008-01-01

    In a recent paper [D. Torrent, A. Hakansson, F. Cervera, and J. Sanchez-Dehesa, Phys. Rev. Lett. 96, 204302 (2006)] inspected the effective parameters of a cluster containing an ensemble of scatterers with a periodic or a weakly disordered arrangement. A small amount of disorder is shown to have a small influence on the characteristics of the acoustic wave propagation with respect to the periodic case. In this Brief Report, we inspect further the effect of a deviation in the scatterer distribution from the periodic distribution. The quasicrystalline approximation is shown to be an efficient tool to quantify this effect. An analytical formula for the effective wave number is obtained in one-dimensional acoustic medium and is compared with the Berryman result in the low-frequency limit. Direct numerical calculations show a good agreement with the analytical predictions

  19. Krsko NPP Periodic Safety Review program

    International Nuclear Information System (INIS)

    Basic, I.; Spiler, J.; Novsak, M.

    2001-01-01

    The need for conducting a Periodic Safety Review for the Krsko NPP has been clearly recognized both by the NEK and the regulator (SNSA). The PSR would be highly desirable both in the light of current trends in safety oversight practices and because of many benefits it is capable to provide. On January 11, 2001 the SNSA issued a decision requesting the Krsko NPP to prepare a program and determine a schedule for the implementation of the program for 'Periodic Safety Review of NPP Krsko'. The program, which is required to be in accordance with the IAEA safety philosophy and with the EU practice, was submitted for the approval to the SNSA by the end of March 2001. The paper summarizes Krsko NPP Periodic Safety Review Program [1] including implemented SNSA and IAEA Expert Mission comments.(author)

  20. Subdomain Precise Integration Method for Periodic Structures

    Directory of Open Access Journals (Sweden)

    F. Wu

    2014-01-01

    Full Text Available A subdomain precise integration method is developed for the dynamical responses of periodic structures comprising many identical structural cells. The proposed method is based on the precise integration method, the subdomain scheme, and the repeatability of the periodic structures. In the proposed method, each structural cell is seen as a super element that is solved using the precise integration method, considering the repeatability of the structural cells. The computational efforts and the memory size of the proposed method are reduced, while high computational accuracy is achieved. Therefore, the proposed method is particularly suitable to solve the dynamical responses of periodic structures. Two numerical examples are presented to demonstrate the accuracy and efficiency of the proposed method through comparison with the Newmark and Runge-Kutta methods.

  1. [Hypertension and pregnancy: Post-partum period].

    Science.gov (United States)

    Hugon-Rodin, Justine; Plu-Bureau, Geneviève

    2016-01-01

    Post-partum period is associated with specific characteristics in women with gestational disorders or preeclampsia. For breastfeeding women, the choice of antihypertensive treatment should take into account the impact on child health. The impact of breastfeeding on health mother must be also discussed. Moreover, for lactation inhibition, bromocriptine should not be used, especially in the context of gestational disorders. In post-partum period, the best contraceptive strategy is only-progestin contraception or non-hormonal contraceptives use. However, this choice will depend on the stabilization or normalization of blood pressure in early post-partum period. Finally, several consultations should be suggested: an information and announcement to explain the consequences of these gestational disorders and organize their multidisciplinary management and follow-up. A preconceptional consultation takes its place to anticipate potential recurrent preeclampsia or gestational hypertension and to schedule a future pregnancy in optimal conditions. Copyright © 2016. Published by Elsevier Masson SAS.

  2. Quasi-periodicity in deep redshift surveys

    International Nuclear Information System (INIS)

    Weygaert, R. van de

    1991-01-01

    The recent result by Broadhurst et al., (1990. Nature 343, 726) showing a striking, nearly periodic, galaxy redshift distribution in a narrow pencil-beam survey, is explained within the Voronoi cellular model of clustering of galaxies. Galaxies, whose luminosities are selected from a Schechter luminosity function, are placed randomly within the walls of this cellular model. Narrow and deep, magnitude-limited, pencil-beam surveys through these structures are simulated. Some 15 per cent of these beams show that observed regular pattern, with a spacing between the peaks of the order of 105 h -1 -150 h -1 Mpc, but most pencil-beams show peaks in the redshift distribution without periodicity, so we may conclude that, even within a cellular universe, periodicity is not a common phenomenon. (author)

  3. Vlasov dynamics of periodically driven systems

    Science.gov (United States)

    Banerjee, Soumyadip; Shah, Kushal

    2018-04-01

    Analytical solutions of the Vlasov equation for periodically driven systems are of importance in several areas of plasma physics and dynamical systems and are usually approximated using ponderomotive theory. In this paper, we derive the plasma distribution function predicted by ponderomotive theory using Hamiltonian averaging theory and compare it with solutions obtained by the method of characteristics. Our results show that though ponderomotive theory is relatively much easier to use, its predictions are very restrictive and are likely to be very different from the actual distribution function of the system. We also analyse all possible initial conditions which lead to periodic solutions of the Vlasov equation for periodically driven systems and conjecture that the irreducible polynomial corresponding to the initial condition must only have squares of the spatial and momentum coordinate. The resulting distribution function for other initial conditions is aperiodic and can lead to complex relaxation processes within the plasma.

  4. Periodic safety analyses; Les essais periodiques

    Energy Technology Data Exchange (ETDEWEB)

    Gouffon, A; Zermizoglou, R

    1990-12-01

    The IAEA Safety Guide 50-SG-S8 devoted to 'Safety Aspects of Foundations of Nuclear Power Plants' indicates that operator of a NPP should establish a program for inspection of safe operation during construction, start-up and service life of the plant for obtaining data needed for estimating the life time of structures and components. At the same time the program should ensure that the safety margins are appropriate. Periodic safety analysis are an important part of the safety inspection program. Periodic safety reports is a method for testing the whole system or a part of the safety system following the precise criteria. Periodic safety analyses are not meant for qualification of the plant components. Separate analyses are devoted to: start-up, qualification of components and materials, and aging. All these analyses are described in this presentation. The last chapter describes the experience obtained for PWR-900 and PWR-1300 units from 1986-1989.

  5. Periodic solutions of Volterra integral equations

    Directory of Open Access Journals (Sweden)

    M. N. Islam

    1988-01-01

    Full Text Available Consider the system of equationsx(t=f(t+∫−∞tk(t,sx(sds,           (1andx(t=f(t+∫−∞tk(t,sg(s,x(sds.       (2Existence of continuous periodic solutions of (1 is shown using the resolvent function of the kernel k. Some important properties of the resolvent function including its uniqueness are obtained in the process. In obtaining periodic solutions of (1 it is necessary that the resolvent of k is integrable in some sense. For a scalar convolution kernel k some explicit conditions are derived to determine whether or not the resolvent of k is integrable. Finally, the existence and uniqueness of continuous periodic solutions of (1 and (2 are btained using the contraction mapping principle as the basic tool.

  6. NASA Ames Fluid Mechanics Laboratory research briefs

    Science.gov (United States)

    Davis, Sanford (Editor)

    1994-01-01

    The Ames Fluid Mechanics Laboratory research program is presented in a series of research briefs. Nineteen projects covering aeronautical fluid mechanics and related areas are discussed and augmented with the publication and presentation output of the Branch for the period 1990-1993.

  7. Postulates of quantum mechanics

    International Nuclear Information System (INIS)

    Cohen-Tannoudji, Claude; Diu, Bernard; Laloe, Franck.

    1977-01-01

    Postulates of quantum mechanics and physical interpretation on observables and their measurement are presented. The physical content of Schroedinger equation, the superposition principle and the physical forecastings are also exposed. In complement are also presented: physical study of a particle in a infinite potential well; study of probability current; mean deviations of two conjugate observables; measurements on a part only of a physical system; density operator; evolution operator; Heisenberg and Schoredinger pictures; gauge invariance; propagator of the Schroedinger equation; unsteady levels lifetime; bound states of a particle in a potential well of any shape; non-bound states of a particle in a well or a potential barrier of some shape; quantum properties of a particle in a one-dimensional periodic structure [fr

  8. Mechanisms of Phosphine Toxicity

    Directory of Open Access Journals (Sweden)

    Nisa S. Nath

    2011-01-01

    Full Text Available Fumigation with phosphine gas is by far the most widely used treatment for the protection of stored grain against insect pests. The development of high-level resistance in insects now threatens its continued use. As there is no suitable chemical to replace phosphine, it is essential to understand the mechanisms of phosphine toxicity to increase the effectiveness of resistance management. Because phosphine is such a simple molecule (PH3, the chemistry of phosphorus is central to its toxicity. The elements above and below phosphorus in the periodic table are nitrogen (N and arsenic (As, which also produce toxic hydrides, namely, NH3 and AsH3. The three hydrides cause related symptoms and similar changes to cellular and organismal physiology, including disruption of the sympathetic nervous system, suppressed energy metabolism and toxic changes to the redox state of the cell. We propose that these three effects are interdependent contributors to phosphine toxicity.

  9. Tunable band gaps in bio-inspired periodic composites with nacre-like microstructure

    Science.gov (United States)

    Chen, Yanyu; Wang, Lifeng

    2014-08-01

    Periodic composite materials have many promising applications due to their unique ability to control the propagation of waves. Here, we report the existence and frequency tunability of complete elastic wave band gaps in bio-inspired periodic composites with nacre-like, brick-and-mortar microstructure. Numerical results show that complete band gaps in these periodic composites derive from local resonances or Bragg scattering, depending on the lattice angle and the volume fraction of each phase in the composites. The investigation of elastic wave propagation in finite periodic composites validates the simulated complete band gaps and further reveals the mechanisms leading to complete band gaps. Moreover, our results indicate that the topological arrangement of the mineral platelets and changes of material properties can be utilized to tune the evolution of complete band gaps. Our finding provides new opportunities to design mechanically robust periodic composite materials for wave absorption under hostile environments, such as for deep water applications.

  10. Impact of the infectious period on epidemics

    Science.gov (United States)

    Wilkinson, Robert R.; Sharkey, Kieran J.

    2018-05-01

    The duration of the infectious period is a crucial determinant of the ability of an infectious disease to spread. We consider an epidemic model that is network based and non-Markovian, containing classic Kermack-McKendrick, pairwise, message passing, and spatial models as special cases. For this model, we prove a monotonic relationship between the variability of the infectious period (with fixed mean) and the probability that the infection will reach any given subset of the population by any given time. For certain families of distributions, this result implies that epidemic severity is decreasing with respect to the variance of the infectious period. The striking importance of this relationship is demonstrated numerically. We then prove, with a fixed basic reproductive ratio (R0), a monotonic relationship between the variability of the posterior transmission probability (which is a function of the infectious period) and the probability that the infection will reach any given subset of the population by any given time. Thus again, even when R0 is fixed, variability of the infectious period tends to dampen the epidemic. Numerical results illustrate this but indicate the relationship is weaker. We then show how our results apply to message passing, pairwise, and Kermack-McKendrick epidemic models, even when they are not exactly consistent with the stochastic dynamics. For Poissonian contact processes, and arbitrarily distributed infectious periods, we demonstrate how systems of delay differential equations and ordinary differential equations can provide upper and lower bounds, respectively, for the probability that any given individual has been infected by any given time.

  11. El pacto periodístico

    OpenAIRE

    Ma. de Lourdes Romero Álvarez

    2002-01-01

    En este artículo se plantea una de las cuestiones fundamentales sobre las que se realiza la actividad periodística y que la autora ha llamado el pacto periodístico. El pacto, celebrado entre el periodista y sus lectores, consiste en que el emisor expresa lo que sucedió tal y como lo vio y el destinatario acepta lo expresado en las mismas condiciones. El compromiso entre ambos participantes los obliga a saber y cumplir con lo estipulado en el contrato, para evitar que alguna de ...

  12. Pulsation properties of Mira long period variables

    International Nuclear Information System (INIS)

    Cahn, J.H.

    1980-01-01

    A matter of great interest to variable star students concerns the mode of pulsation of Mira long period variables. In this report we first give observational evidence for the pulsation constant Q. We then compare the observations with calculations. Next, we review two interesting groups of papers dealing with hydrodynamic properties of long period variables. In the first, a fully dynamic nonlinear calculation maps out the Mira instability domain. In the second, special attention is paid to shock propagation beyond the photosphere which in large measure accounts for the complex spectra from this region. (orig./WL)

  13. Short period tidal variations of earth rotation

    Science.gov (United States)

    Yoder, C. F.; Williams, J. G.; Parke, M. E.; Dickey, J. O.

    1981-01-01

    It is explained that the tidal deformation of the earth's polar moment of inertia by the moon and sun cause periodic variations in rotation. The short period oscillations give rise to a meter-sized, diurnal signature in the lunar laser ranging data obtained at McDonald Observatory. A solution is given for the scale parameter k/C at fortnightly and monthly tidal frequencies. The results are compared with those obtained by other investigators and with a theoretical estimate which includes the effect of oceans and a decoupled fluid core.

  14. Mathematics of Periodic Tables for Benzenoid Hydrocarbons.

    Science.gov (United States)

    Dias, Jerry Ray

    2007-01-01

    The upper and lower bounds for invariants of polyhex systems based on the Harary and Harborth inequalities are studied. It is shown that these invariants are uniquely correlated by the Periodic Table for Benzenoid Hydrocarbons. A modified periodic table for total resonant sextet (TRS) benzenoids based on the invariants of Ds and r(empty) is presented; Ds is the number of disconnections among the empty rings for fused TRS benzenoid hydrocarbons. This work represents a contribution toward deciphering the topological information content of benzenoid formulas.

  15. Orbital Period Changes in WZ Sagittae

    Science.gov (United States)

    Patterson, Joseph; Stone, Geoffrey; Kemp, Jonathan; Skillman, David R.; de Miguel, Enrique; Potter, Michael; Starkey, Donn; Uthas, Helena; Jones, Jim; Slauson, Douglas; Koff, Robert; Myers, Gordon; Menzies, Kenneth; Campbell, Tut; Roberts, George; Foote, Jerry; Vanmunster, Tonny; Cook, Lewis M.; Krajci, Thomas; Ogmen, Yenal; Sabo, Richard; Seargeant, Jim

    2018-06-01

    We report a long-term (1961–2017) study of the eclipse times in the dwarf nova WZ Sagittae, in an effort to learn its rate of orbital-period change. Some wiggles with a timescale of 20–50 years are apparent, and a connection with the ∼23 year interval between dwarf-nova eruptions is possible. These back-and-forth wiggles dominate the O–C diagram, and prevent a secure measurement of the steady rate of orbital-period change.

  16. Radiocarbon clock strikes the glacial period pulse

    International Nuclear Information System (INIS)

    Serebryannyj, L.R.

    1976-01-01

    Discussed are some aspects of the theory of radiocarbon dating in application to the study of the history of the Earth. The accumulation and the decay of C 14 and methods for its recording are desribed. Presented is a block diagram of a scintillation counter for recording C 14 . The chronology of the last glaciation of Europe has been determined: the Interglacial period (between 50 and 40 thousand years) a prolonged preglacil period (between 40 and 25 thousand years), the last glaciation (between 25 and 10 thousand years ago)

  17. [Hypoglycaemic periodic paralysis in hyperthyroidism patients].

    Science.gov (United States)

    Kratochvíl, J; Masopust, J; Martínková, V; Charvát, J

    2008-11-01

    Hypokalemic periodic paralysis (HPP) is a rare disorder characterised by acute, potentially fatal atacks of muscle weakness or paralysis. Massive shift of potassium into cells is caused by elevated levels of insulin and catecholamines in the blood. Hypophosphatemia and hypomagnesemia may be also present. Acidobasic status usually is not impaired. HPP occurs as familiar (caused by ion channels inherited defects) or acquired (in patients with hyperthyroidism). On the basis of two clinical cases we present a review of hypokalemic periodic paralysis in hyperthyroid patients. We discuss patogenesis, clinical and laboratory findings as well as the principles of prevention and treatment of this rare disorder.

  18. Using periodicity to mitigate ground vibration

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard

    2015-01-01

    Introduction of trenches, barriers and wave impeding blocks on the transmission path between a source and receiver can be used for mitigation of ground vibration. However, to be effective a barrier must have a depth of about one wavelength of the waves to be mitigated. Hence, while great reductions......: A soil with periodic stiffening (ground improvement) and a ground with periodic changes in the surface elevation obtained by artificial landscaping. By means of a two-dimensional finite-element model, the stiffness and mass matrices are determined for a single cell of the ground with horizonal...

  19. Reconstruction of periodic signals using neural networks

    Directory of Open Access Journals (Sweden)

    José Danilo Rairán Antolines

    2014-01-01

    Full Text Available In this paper, we reconstruct a periodic signal by using two neural networks. The first network is trained to approximate the period of a signal, and the second network estimates the corresponding coefficients of the signal's Fourier expansion. The reconstruction strategy consists in minimizing the mean-square error via backpro-pagation algorithms over a single neuron with a sine transfer function. Additionally, this paper presents mathematical proof about the quality of the approximation as well as a first modification of the algorithm, which requires less data to reach the same estimation; thus making the algorithm suitable for real-time implementations.

  20. Periodic Boundary Motion in Thermal Turbulence

    International Nuclear Information System (INIS)

    Zhang, Jun; Libchaber, Albert

    2000-01-01

    A free-floating plate is introduced in a Benard convection cell with an open surface. It partially covers the cell and distorts the local heat flux, inducing a coherent flow that in turn moves the plate. Remarkably, the plate can be driven to a periodic motion even under the action of a turbulent fluid. The period of the oscillation depends on the coverage ratio, and on the Rayleigh number of the convective system. The plate oscillatory behavior observed in this experiment may be related to a geological model, in which continents drift in a quasiperiodic fashion. (c) 2000 The American Physical Society

  1. On Helmholtz Problem for Plane Periodical Structures

    International Nuclear Information System (INIS)

    Akishin, P.G.; Vinitskij, S.I.

    1994-01-01

    The plane Helmholtz problem of the periodical disc structures with the phase shifts conditions of the solutions along the basis lattice vectors and the Dirichlet conditions on the basic boundaries is considered. The Green function satisfying the quasi periodical conditions on the lattice is constructed. The Helmholtz problem is reduced to the boundary integral equations for the simple layer potentials of this Green function. The methods of the discretization of the arising integral equations are proposed. The procedures of calculation of the matrix elements are discussed. The reality of the spectral parameter of the nonlinear continuous and discretized problems is shown. 8 refs., 2 figs

  2. APPLE-II type quasi-periodic variably polarizing undulator at HiSOR

    International Nuclear Information System (INIS)

    Sasaki, Shigemi; Miyamoto, Atsushi; Goto, Kiminori

    2012-01-01

    A newly constructed quasi-periodic APPLE-II undulator was installed in the HiSOR ring at Hiroshima Synchrotron Radiation Center, Hiroshima University during the summer shutdown period in 2011. This 1.8 m-long undulator has a period length of 78 mm. In this article, the mechanism of magnetic field generation for various polarization modes of APPLE undulator, the principle of quasi-periodic undulator and the performance of HiSOR QP-APPLE-II undulator are described. (author)

  3. The auxetic behavior of an expanded periodic cellular structure

    Science.gov (United States)

    Ciolan, Mihaela A.; Lache, Simona; Velea, Marian N.

    2018-02-01

    Within nowadays research, when it comes to lightweight sandwich panels, periodic cellular structures are considered real trendsetters. One of the most used type of core in producing sandwich panels is the honeycomb. However, due to its relatively high manufacturing cost, this structure has limited applications; therefore, research has been carried out in order to develop alternative solutions. An example in this sense is the ExpaAsym cellular structure, developed at the Transilvania University of Braşov; it represents a periodic cellular structure manufactured through a mechanically expansion process of a previously cut and perforated sheet material. The relative density of the structure was proven to be significantly lower than the one of the honeycomb. This gives a great advantage to the structure, due to the fact that when the internal angle A of the unit cell is 60°, after the mechanical expansion it results a hexagonal structure. The main objective of this paper is to estimate the in-plane Poisson ratios of the structure, in terms of its geometrical parameters. It is therefore analytically shown that for certain values of the geometric parameters, the in-plane Poisson ratios have negative values when the internal angle exceeds 90°, which determines its auxetic behavior.

  4. Annual Research Review: Epigenetic Mechanisms and Environmental Shaping of the Brain during Sensitive Periods of Development

    Science.gov (United States)

    Roth, Tania L.; Sweatt, J. David

    2011-01-01

    Experiences during early development profoundly affect development of the central nervous system (CNS) to impart either risk for or resilience to later psychopathology. Work in the developmental neuroscience field is providing compelling data that epigenetic marking of the genome may underlie aspects of this process. Experiments in rodents…

  5. Mechanism of single-pulse ablative generation of laser-induced periodic surface structures

    Czech Academy of Sciences Publication Activity Database

    Shugaev, M.V.; Gnilitskyi, I.; Bulgakova, Nadezhda M.; Zhigilei, L.

    2017-01-01

    Roč. 96, č. 20 (2017), s. 1-9, č. článku 205429. ISSN 2469-9950 R&D Projects: GA MŠk LO1602; GA ČR GA16-12960S; GA MŠk LM2015086 EU Projects: European Commission(XE) 739573 - HiLASE CoE Grant - others:OP VVV - HiLASE-CoE(XE) CZ.02.1.01/0.0/0.0/15_006/0000674 Institutional support: RVO:68378271 Keywords : molecular-dynamics simulations * metals * electron * spallation Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 3.836, year: 2016

  6. Periodic Ground State Configurations in a One-Dimensional Hubbard Model of Statistical Mechanics

    International Nuclear Information System (INIS)

    Kipnis, M. M.

    2000-01-01

    This paper considers an averaging procedure for the description of a particles arrangement in a Hubbard model with antiferromagnetic interactions. The arrangements are described by the devil's staircase. Completeness of the staircase is proved

  7. Mechanical properties test data for structural materials. Quarterly progress report for period ending October 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Hill, M R [comp.

    1976-12-01

    Test data on heat resisting reactor materials are presented. These data were obtained in research at EG and G Idaho, Argonne National Laboratory, Oak Ridge National Laboratory, Naval Research Laboratory, Hanford Engineering Development Laboratory, Westinghouse Advanced Reactors Division, General Electric Company, University of Cincinnati, and University of California at Los Angeles. (JRD)

  8. Culture and Cooperation during the Interwar Period

    Directory of Open Access Journals (Sweden)

    Anişoara Popa

    2015-05-01

    Full Text Available Starting from the most important Publications of the International Institute for Intellectual Cooperation (1925-1946 we will explore the ideas concerning culture and personalities involved in the intellectual cooperation during the Interwar Period. Pointing out the role that the International Institute of Intellectual Cooperation had and the Romanian contribution to this cooperation is another purpose of this article.

  9. Periodic Solutions for Highly Nonlinear Oscillation Systems

    DEFF Research Database (Denmark)

    Ghadimi, M; Barari, Amin; Kaliji, H.D

    2012-01-01

    In this paper, Frequency-Amplitude Formulation is used to analyze the periodic behavior of tapered beam as well as two complex nonlinear systems. Many engineering structures, such as offshore foundations, oil platform supports, tower structures and moving arms, are modeled as tapered beams...

  10. Resonances in a periodically driven bosonic system

    Science.gov (United States)

    Quelle, Anton; Smith, Cristiane Morais

    2017-11-01

    Periodically driven systems are a common topic in modern physics. In optical lattices specifically, driving is at the origin of many interesting phenomena. However, energy is not conserved in driven systems, and under periodic driving, heating of a system is a real concern. In an effort to better understand this phenomenon, the heating of single-band systems has been studied, with a focus on disorder- and interaction-induced effects, such as many-body localization. Nevertheless, driven systems occur in a much wider context than this, leaving room for further research. Here, we fill this gap by studying a noninteracting model, characterized by discrete, periodically spaced energy levels that are unbounded from above. We couple these energy levels resonantly through a periodic drive, and discuss the heating dynamics of this system as a function of the driving protocol. In this way, we show that a combination of stimulated emission and absorption causes the presence of resonant stable states. This will serve to elucidate the conditions under which resonant driving causes heating in quantum systems.

  11. 5 CFR 317.503 - Probationary period.

    Science.gov (United States)

    2010-01-01

    .... (b) When a career appointee's executive qualification have been certified by a Qualifications Review... THE SENIOR EXECUTIVE SERVICE Career Appointments § 317.503 Probationary period. (a) An individual's initial appointment as an SES career appointee becomes final only after the individual has served a 1-year...

  12. New Realization of Periodic Cycled Separation

    DEFF Research Database (Denmark)

    Toftegard, Bjarne; Clausen, Charlotte H.; Jørgensen, Sten B.

    2016-01-01

    are drained sequentially rather than simultaneously, such that the vapor flow is not interrupted during the liquid drainage. For different ratios of counter-current vapor/liquid flow rates, column efficiencies for periodically cycled columns are shown experimentally to be two times greater than those...

  13. Teaching the Hitler Period: History and Morality.

    Science.gov (United States)

    Mork, Gordon R.

    1980-01-01

    Outlines six approaches used in a university history course which address the problems of teaching the Hitler period. The assumption underlying all the approaches is that Americans are not entirely different from Germans and that they may be faced with similar moral choices. The approaches avoid the didactic moralism often taught about this era.…

  14. Vitamins and administration periods effects on haematological ...

    African Journals Online (AJOL)

    Vitamins and administration periods effects on haematological parameters of broiler ... Data obtained on haematological indices were subjected to Analysis of ... été répartis sur base de l'égalisation du poids en neuf (9) groupes de traitement, ...

  15. Regular arrangement of periodates bound to lysozyme

    Czech Academy of Sciences Publication Activity Database

    Ondráček, Jan; Weiss, M.S.; Brynda, Jiří; Fiala, J.; Jursík, F.; Řezáčová, Pavlína; Jenner, L.B.; Sedláček, Juraj

    2005-01-01

    Roč. 61, Pt9 (2005), s. 1181-1189 ISSN 0907-4449 Institutional research plan: CEZ:AV0Z50520514 Keywords : hen egg white lysozyme * periodate * epitaxy Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.401, year: 2005

  16. QS Spiral: Visualizing Periodic Quantified Self Data

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Cuttone, Andrea; Jørgensen, Sune Lehmann

    2013-01-01

    In this paper we propose an interactive visualization technique QS Spiral that aims to capture the periodic properties of quantified self data and let the user explore those recurring patterns. The approach is based on time-series data visualized as a spiral structure. The interactivity includes ...

  17. Gestation period and twinning in chimpanzees.

    Science.gov (United States)

    PEACOCK, L J; ROGERS, C M

    1959-04-10

    The length of the gestation period in 118 births in a colony of chimpanzees was found to be 226.8 days, with a standard deviation of 13.3 and a range of 196 to 260 days. Six pairs of twins were born in 120 parturitions; thus the apparent twinning rate is higher than that in man.

  18. Theory of periodic conjugate heat transfer

    CERN Document Server

    Zudin, Yuri B

    2016-01-01

    This book presents the theory of periodic conjugate heat transfer in detail. It offers a simplified description of the interaction between a solid body and a fluid as a boundary value problem of the heat conduction equation for the solid body.

  19. Periodic diffeomorphisms on homotopy E (4) surfaces

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 124; Issue 3. Periodic Diffeomorphisms on Homotopy (4) Surfaces. Hongxia Li. Volume 124 Issue 3 August 2014 pp 437-445. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/pmsc/124/03/0437-0445 ...

  20. Pleural effusions in the postpartum period

    International Nuclear Information System (INIS)

    Stark, P.; Pollack, M.S.

    1986-01-01

    We report on the high frequency of pleural effusions in the immediate postpartum period. Forty-four out of 45 women who examined within 24-48 h after delivery showed evidence of pleural fluid. Under these circumstances, this pleural abnormality should not be considered an indicator of serious cardiopulmonary disease. (orig.) [de