939 resultados para Lightcone fluctuation


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Pollutants that once enter into the earth’s atmosphere become part of the atmosphere and hence their dispersion, dilution, direction of transportation etc. are governed by the meteorological conditions. The thesis deals with the study of the atmospheric dispersion capacity, wind climatology, atmospheric stability, pollutant distribution by means of a model and the suggestions for a comprehensive planning for the industrially developing city, Cochin. The definition, sources, types and effects of air pollution have been dealt with briefly. The influence of various meteorological parameters such as vector wind, temperature and its vertical structure and atmospheric stability in relation to pollutant dispersal have been studied. The importance of inversions, mixing heights, ventilation coefficients were brought out. The spatial variation of mixing heights studies for the first time on a microscale region, serves to delineate the regions of good and poor dispersal capacity. A study of wind direction fluctuation, σθ and its relation to stability and mixing heights were shown to be much useful. It was shown that there is a necessity to look into the method of σθ computation. The development of Gausssian Plume Model along with the application for multiple sources was presented. The pollutant chosen was sulphur dioxide and industrial sources alone were considered. The percentage frequency of occurrence of inversions and isothermals are found to be low in all months during the year. The spatial variation of mixing heights revealed that a single mixing height cannot be taken as a representative for the whole city have low mixing heights and monsoonal months showed lowest mixing heights. The study of ventilation co-efficients showed values less than the required optimum value 6000m2/5. However, the low values may be due to the consideration of surface wind alone instead of the vertically averaged wind. Relatively more calm conditions and light winds during night and strong winds during day time were observed. During the most of the year westerlies during day time and northeasterlies during night time are the dominant winds. Unstable conditions with high values of σθ during day time and stable conditions with lower values of σθ during night time are the prominent features. Monsoonal months showed neutral stability for most of the time. A study σθ of and Pasquill Stability category has revealed the difficulty in giving a unique value of for each stability category. For the first time regression equations have been developed relating mixing heights and σθ. A closer examination of σθ revealed that half of the range of wind direction fluctuations is to be taken, instead of one by sixth, to compute σθ. The spatial distribution of SO2 showed a more or less uniform distribution with a slight intrusion towards south. Winter months showed low concentrations contrary to the expectations. The variations of the concentration is found to be influenced more by the mixing height and the stack height rather than wind speed. In the densely populated areas the concentration is more than the threshold limit value. However, the values reported appear to be high, because no depletion of the material is assumed through dry or wet depositions and also because of the inclusion of calm conditions with a very light wind speed. A reduction of emission during night time with a consequent rise during day time would bring down the levels of pollution. The probable locations for the new industries could be the extreme southeast parts because the concentration towards the north falls off very quickly resulting low concentrations. In such a case pollutant spread would be towards south and west, thus keeping the city interior relatively free from pollution. A more detailed examination of the pollutant spread by means of models that would take the dry and wet depositions may be necessary. Nevertheless, the present model serves to give the trend of the distribution of pollutant concentration with which one can suggest the optimum locations for the new industries

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Chapter 1 presents a brief note on the state at which the construction industry stands at present, bringing into focus the significance of the critical study. Relevance of the study, area of investigation and objectives of the study are outlined in this chapter. The 2nd chapter presents a review of the literature on the relevant areas. In the third chapter an analysis on time and cost overrun in construction highlighting the major factors responsible for it has been done. A couple of case studies to estimate loss to the nation on account of delay in construction have been presented in the chapter. The need for an appropriate estimate and a competent contractor has been emphasised for improving effectiveness in the project implementation. Certain useful equations and thoughts have been formulated on this area in this chapter that can be followed in State PWD and other Govt. organisations. Case studies on project implementation of major projects undertaken by Government sponsored/supported organizations in Kerala have been dealt with in Chapter 4. A detailed description of the project of Kerala Legislature Complex with a critical analysis has been given in this chapter. A detailed account of the investigations carried out on the construction of International Stadium, a sports project of Greater Cochin Development Authority is included here. The project details of Cochin International Airport at Nedumbassery, its promoters and contractors are also discussed in Chapter 4. Various aspects of implementation which led the above projects successful have been discussed in chapter 5. The data collected were analysed through discussion and perceptions to arrive at certain conclusions. The emergence of front-loaded contract and its impact on economics of the project execution are dealt with in this chapter. Analysis of delays in respect of the various project narrated in chapter 3 has been done here. The root causes of the project time and overrun and its remedial measures are also enlisted in this chapter. Study of cost and time overrun of any construction project IS a part of construction management. Under the present environment of heavy investment on construction activities in India, the consequences of mismanagement many a time lead to excessive expenditure which are not be avoidable. Cost consciousness, therefore has to be keener than ever before. Optimization in investment can be achieved by improved dynamism in construction management. The successful completion of coristruction projects within the specified programme, optimizing three major attributes of the process - quality, schedule and costs - has become the most valuable and challenging task for the engineer - managers to perform. So, the various aspects of construction management such as cost control, schedule control, quality assurance, management techniques etc. have also been discussed in this fifth chapter. Chapter 6 summarises the conclusions drawn from the above criticalr1 of rhajor construction projects in Kerala.

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In classical field theory, the ordinary potential V is an energy density for that state in which the field assumes the value ¢. In quantum field theory, the effective potential is the expectation value of the energy density for which the expectation value of the field is ¢o. As a result, if V has several local minima, it is only the absolute minimum that corresponds to the true ground state of the theory. Perturbation theory remains to this day the main analytical tool in the study of Quantum Field Theory. However, since perturbation theory is unable to uncover the whole rich structure of Quantum Field Theory, it is desirable to have some method which, on one hand, must go beyond both perturbation theory and classical approximation in the points where these fail, and at that time, be sufficiently simple that analytical calculations could be performed in its framework During the last decade a nonperturbative variational method called Gaussian effective potential, has been discussed widely together with several applications. This concept was described as a means of formalizing our intuitive understanding of zero-point fluctuation effects in quantum mechanics in a way that carries over directly to field theory.

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We analyze the heat transfer between two nanoparticles separated by a distance lying in the near-field domain in which energy interchange is due to the Coulomb interactions. The thermal conductance is computed by assuming that the particles have charge distributions characterized by fluctuating multipole moments in equilibrium with heat baths at two different temperatures. This quantity follows from the fluctuation-dissipation theorem for the fluctuations of the multipolar moments. We compare the behavior of the conductance as a function of the distance between the particles with the result obtained by means of molecular dynamics simulations. The formalism proposed enables us to provide a comprehensive explanation of the marked growth of the conductance when decreasing the distance between the nanoparticles.

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The thesis deals with the study of super conducting properties of layered cuprates within the frame work of a modified Lawrence-Doniach (LD) model. The thesis is organized in seven chapters. Chapter I is a survey of the phenomena and theories of conventional superconductivity which can serve as a springboard for launching the study of the new class of oxide superconductors and it also includes a chronological description of the efforts made to overcome the temperature barrier. Chapter II deals with the structure and properties of the copper oxide superconductors and also the experimental constraints on the theories of high te:::nperature superconductivity. A modified Lawrence-Doniach type of phenomenological model which forms the basis of the presnt study is also discussed. In chapter III~ the temperature dependence of the upper critical field both parallel and perpendicular to the layers is determined and the results are compared with d.c. magnetization measurements on different superconducting compoilllds. The temperature and angular dependence of the lower critical field both parallel and perpendicular to the layers is also discussed. Chapters IV, V and VI deal with thermal fluctuation effects on superconducting properties. Fluctuation specific heat is studied in chapter IV. Paraconductivity both parallel and perpendicular to the layers is discussed in chapter V. Fluctuation diamagnetism is dealt with in chapter VI. Dimensional cross over in the fluctuation regime of all these quantities is also discussed. Chapter VII gives a summary of the results and the conclusions arrived at.

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In Sri Lanka policy responses have direct impacts on rural dwellers. Over 80% of Sri Lanka’s population live in rural areas and 90% of them represent low income dwellers. Their production system may be hampered by fragmented landholding, poor economics of scale, low investment levels resulting from poor financial services as well as inappropriate or limited technology. They are vulnerable to price hikes of basic foods and food security issues due to fragmented landholding and poor financial services. Policy measures to reduce the transmission of higher international prices in domestic markets exist to protect the food security of the vulnerable population. This paper will discuss the food policy and strategies implemented by the government and outside to the above facts this paper also describes the effectiveness of the policies forwarded by the government. The objective of this study is to analyse the impact of policy responses to the food price crisis and rural food security in Sri Lanka. Outside of the above facts this study also treats the impact of policies and decisions on the nutritional condition of rural dwellers. Furthermore this study is to analyse the fluctuation of buying power with the price hikes and the relation of above facts with issues like malnutrition. This paper discusses why policy makers should pay greater attention to rural dwellers and describes the multiple pathways through which food price increases have on rural people. It also provides evidence of the impact of this crisis in particular, through hidden hunger, and discusses how current policy responses should adjust and improve to protect the rural dwellers in the short and long term.

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En la presente monografía se propondrá responder a la pregunta ¿De qué manera los discursos políticos de los líderes de la Transición española, Adolfo Suárez, Felipe González, Manuel Fraga y Santiago Carrillo, jugaron un papel en la construcción democrática durante las coyunturas políticas vividas entre los años 1976 y 1982 en España? Ante esto, se planea responder que los discursos políticos de los líderes de la Transición española jugaron un papel en la construcción democrática mediante la elaboración de consensos sociales alrededor de los valores democráticos y la construcción de disensos sociales en torno a las ideologías partidarias, que fluctuaron en intensidad según el Modelo de Contexto elaborado a partir de la coyuntura política respectiva.

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Los resultados financieros de las organizaciones son objeto de estudio y análisis permanente, predecir sus comportamientos es una tarea permanente de empresarios, inversionistas, analistas y académicos. En el presente trabajo se explora el impacto del tamaño de los activos (valor total de los activos) en la cuenta de resultados operativos y netos, analizando inicialmente la relación entre dichas variables con indicadores tradicionales del análisis financiero como es el caso de la rentabilidad operativa y neta y con elementos de estadística descriptiva que permiten calificar los datos utilizados como lineales o no lineales. Descubriendo posteriormente que los resultados financieros de las empresas vigiladas por la Superintendencia de Sociedades para el año 2012, tienen un comportamiento no lineal, de esta manera se procede a analizar la relación de los activos y los resultados con la utilización de espacios de fase y análisis de recurrencia, herramientas útiles para sistemas caóticos y complejos. Para el desarrollo de la investigación y la revisión de la relación entre las variables de activos y resultados financieros se tomó como fuente de información los reportes financieros del cierre del año 2012 de la Superintendencia de Sociedades (Superintendencia de Sociedades, 2012).

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Resumen: Este texto explora el sentido y la posibilidad de introducir la teoría de Ilya Prigogine “estructuras disipativas” en el contexto de las organizaciones. La tesis aquí propuesta afirma que las organizaciones son sistemas abiertos, alejados del equilibrio y tiene que ver con posibilidades creativas, antes que con realidades fácticas. Por lo tanto, las organizaciones de no-equilibrio están constituidas por fenómenos de comportamientos espontáneos o coherentes que reclaman para sobrevivir cierta disipación de energía y, por tanto, el mantenimiento de una interacción con el mundo exterior. Con ello la gerencia adquiere un papel destacado en el estudio de las organizaciones como estructuras disipativas encaminadas a generar y permitir el Biodesarrollo. Palabras claves: Estructuras Disipativas, Fluctuaciones, Bifurcaciones, Gerencia, Biodesarrollo, Auto-eco-organizador. Abstract:  This text explores the sense and possibility of introducing Ilya Prigogine´s theory “dissipative structures”, into organizations´ context. The thesis proposed here states that organizations are open systems which are far away from equilibrium and had to deal with creative possibilities before being practical realities. Thus, no-equilibrium organizations are made of spontaneous or coherent behavioral phenomenon that strives to survive a certain amount of energy loss, hence the maintenance of interaction with external world. This way organizations management acquires an outstanding roll in studying organizations as dissipative structures prone to create and allow bio-development.Key Words: Dissipative Structures, Fluctuation, Bifurcation, Management, Bio-development, eco-self-organizer.

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INTRODUCCION La hipotensión arterial por anestesia raquídea en embarazadas llevadas a cesárea es frecuente y deletérea para la madre y el feto, sin que a la fecha exista una herramienta clínicamente útil para predecirla. La variabilidad de la frecuencia cardiaca es una medida que estima la actividad del sistema nervioso autónomo y algunos estudio iniciales indican una posible utilidad como herramienta predictiva de hipotensión arterial en esta población. METODOLOGIA Se realizó un estudio observacional descriptivo para examinar el comportamiento de la variabilidad de la frecuencia cardiaca, medida como razón de Baja frecuencia/Alta frecuencia, con un punto de corte de 2.5 tomada con un reloj POLAR RS800CX, en una población de pacientes con embarazo a término llevadas a cesárea, en un hospital de tercer nivel en Bogotá- Colombia entre Febrero y Abril del 2015. RESULTADOS El estudio incluyó 82 pacientes. Se determinó que la razón Baja frecuencia/Alta frecuencia mayor a 2,5 era poco frecuente en nuestra población (15.85%), y su asociación no fue significativa. DISCUSION El presente estudio demostró que la asociación entre la presencia de hipotensión y un índice Baja frecuencia/Alta frecuencia con punto de corte de 2.5 no es significativo para nuestra población de mujeres con embarazo a término llevadas a cesárea con anestesia espinal. Según los resultados se sugieres un punto de corte de 1.6 como punto de partida para la realización de nuevos estudios que permitan validar este valor.

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En análisis retrospectivo evaluamos 91 pacientes llevados a cirugía cardiaca entre 2013 y 2014 en la Fundación Cardioinfantil, en quienes se administro Custodiol, analizando los niveles de sodio y osmolalidad plasmática efectiva antes, durante y después del procedimiento quirúrgico. Nosotros evaluamos la relación entre administración de Custodiol y cambios en el sodio y osmolalidad plasmática del paciente llevado a cirugía cardiaca.

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This study investigates the change of the El Niño–Southern Oscillation (ENSO)-South Asian summer monsoon interaction in response to a weakened Atlantic thermohaline circulation (THC) by applying an additional freshwater flux into the North Atlantic. The simulated results indicate that the weakened THC leads to intensified ENSO-South Asian summer monsoon relationship and enhanced South Asian summer monsoon interannual variability. Furthermore, it is suggested that this intensification of the ENSO-monsoon relationship is likely due to the enhanced ENSO variability induced by the weakened THC. This study indicates that the low frequency fluctuation of Atlantic SSTs might have an influence on South Asian summer monsoon interannual variability and the ENSO-monsoon interaction, and suggests a nonlocal mechanism for the observed decadal-multidecadal modulation of ENSO-monsoon relationship.

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Airborne laser altimetry has the potential to make frequent detailed observations that are important for many aspects of studying land surface processes. However, the uncertainties inherent in airborne laser altimetry data have rarely been well measured. Uncertainty is often specified as generally as 20cm in elevation, and 40cm planimetric. To better constrain these uncertainties, we present an analysis of several datasets acquired specifically to study the temporal consistency of laser altimetry data, and thus assess its operational value. The error budget has three main components, each with a time regime. For measurements acquired less than 50ms apart, elevations have a local standard deviation in height of 3.5cm, enabling the local measurement of surface roughness of the order of 5cm. Points acquired seconds apart acquire an additional random error due to Differential Geographic Positioning System (DGPS) fluctuation. Measurements made up to an hour apart show an elevation drift of 7cm over a half hour. Over months, this drift gives rise to a random elevation offset between swathes, with an average of 6.4cm. The RMS planimetric error in point location was derived as 37.4cm. We conclude by considering the consequences of these uncertainties on the principle application of laser altimetry in the UK, intertidal zone monitoring.

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The El Niño–Southern Oscillation (ENSO) is a naturally occurring fluctuation that originates in the tropical Pacific region and affects ecosystems, agriculture, freshwater supplies, hurricanes and other severe weather events worldwide. Under the influence of global warming, the mean climate of the Pacific region will probably undergo significant changes. The tropical easterly trade winds are expected to weaken; surface ocean temperatures are expected to warm fastest near the equator and more slowly farther away; the equatorial thermocline that marks the transition between the wind-mixed upper ocean and deeper layers is expected to shoal; and the temperature gradients across the thermocline are expected to become steeper. Year-to-year ENSO variability is controlled by a delicate balance of amplifying and damping feedbacks, and one or more of the physical processes that are responsible for determining the characteristics of ENSO will probably be modified by climate change. Therefore, despite considerable progress in our understanding of the impact of climate change on many of the processes that contribute to El Niño variability, it is not yet possible to say whether ENSO activity will be enhanced or damped, or if the frequency of events will change.

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Recent coordinated observations of interplanetary scintillation (IPS) from the EISCAT, MERLIN, and STELab, and stereoscopic white-light imaging from the two heliospheric imagers (HIs) onboard the twin STEREO spacecraft are significant to continuously track the propagation and evolution of solar eruptions throughout interplanetary space. In order to obtain a better understanding of the observational signatures in these two remote-sensing techniques, the magnetohydrodynamics of the macro-scale interplanetary disturbance and the radio-wave scattering of the micro-scale electron-density fluctuation are coupled and investigated using a newly constructed multi-scale numerical model. This model is then applied to a case of an interplanetary shock propagation within the ecliptic plane. The shock could be nearly invisible to an HI, once entering the Thomson-scattering sphere of the HI. The asymmetry in the optical images between the western and eastern HIs suggests the shock propagation off the Sun–Earth line. Meanwhile, an IPS signal, strongly dependent on the local electron density, is insensitive to the density cavity far downstream of the shock front. When this cavity (or the shock nose) is cut through by an IPS ray-path, a single speed component at the flank (or the nose) of the shock can be recorded; when an IPS ray-path penetrates the sheath between the shock nose and this cavity, two speed components at the sheath and flank can be detected. Moreover, once a shock front touches an IPS ray-path, the derived position and speed at the irregularity source of this IPS signal, together with an assumption of a radial and constant propagation of the shock, can be used to estimate the later appearance of the shock front in the elongation of the HI field of view. The results of synthetic measurements from forward modelling are helpful in inferring the in-situ properties of coronal mass ejection from real observational data via an inverse approach.