970 resultados para theoretical basis


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Double degree. A Work Project presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA- School of Business and Economics and Warsaw School of Economics

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Introduction The aim of this study was to explore the environment of Echinococcus granulosus (E. granulosus) protoscolices and their relationship with their host. Methods Proteins from the hydatid-cyst fluid (HCF) from E. granulosus were identified by proteomics. An inductively coupled plasma atomic emission spectrometer (ICP-AES) was used to determine the elements, an automatic biochemical analyzer was used to detect the types and levels of biochemical indices, and an automatic amino acid analyzer was used to detect the types and levels of amino acids in the E. granulosus HCF. Results I) Approximately 30 protein spots and 21 peptide mass fingerprints (PMF) were acquired in the two-dimensional gel electrophoresis (2-DE) pattern of hydatid fluid; II) We detected 10 chemical elements in the cyst fluid, including sodium, potassium, calcium, magnesium, copper, and zinc; III) We measured 19 biochemical metabolites in the cyst fluid, and the amount of most of these metabolites was lower than that in normal human serum; IV) We detected 17 free amino acids and measured some of these, including alanine, glycine, and valine. Conclusions We identified and measured many chemical components of the cyst fluid, providing a theoretical basis for developing new drugs to prevent and treat hydatid disease by inhibiting or blocking nutrition, metabolism, and other functions of the pathogen.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The main object of the present paper consists in giving formulas and methods which enable us to determine the minimum number of repetitions or of individuals necessary to garantee some extent the success of an experiment. The theoretical basis of all processes consists essentially in the following. Knowing the frequency of the desired p and of the non desired ovents q we may calculate the frequency of all possi- ble combinations, to be expected in n repetitions, by expanding the binomium (p-+q)n. Determining which of these combinations we want to avoid we calculate their total frequency, selecting the value of the exponent n of the binomium in such a way that this total frequency is equal or smaller than the accepted limit of precision n/pª{ 1/n1 (q/p)n + 1/(n-1)| (q/p)n-1 + 1/ 2!(n-2)| (q/p)n-2 + 1/3(n-3) (q/p)n-3... < Plim - -(1b) There does not exist an absolute limit of precision since its value depends not only upon psychological factors in our judgement, but is at the same sime a function of the number of repetitions For this reasen y have proposed (1,56) two relative values, one equal to 1-5n as the lowest value of probability and the other equal to 1-10n as the highest value of improbability, leaving between them what may be called the "region of doubt However these formulas cannot be applied in our case since this number n is just the unknown quantity. Thus we have to use, instead of the more exact values of these two formulas, the conventional limits of P.lim equal to 0,05 (Precision 5%), equal to 0,01 (Precision 1%, and to 0,001 (Precision P, 1%). The binominal formula as explained above (cf. formula 1, pg. 85), however is of rather limited applicability owing to the excessive calculus necessary, and we have thus to procure approximations as substitutes. We may use, without loss of precision, the following approximations: a) The normal or Gaussean distribution when the expected frequency p has any value between 0,1 and 0,9, and when n is at least superior to ten. b) The Poisson distribution when the expected frequecy p is smaller than 0,1. Tables V to VII show for some special cases that these approximations are very satisfactory. The praticai solution of the following problems, stated in the introduction can now be given: A) What is the minimum number of repititions necessary in order to avoid that any one of a treatments, varieties etc. may be accidentally always the best, on the best and second best, or the first, second, and third best or finally one of the n beat treatments, varieties etc. Using the first term of the binomium, we have the following equation for n: n = log Riim / log (m:) = log Riim / log.m - log a --------------(5) B) What is the minimun number of individuals necessary in 01der that a ceratin type, expected with the frequency p, may appaer at least in one, two, three or a=m+1 individuals. 1) For p between 0,1 and 0,9 and using the Gaussean approximation we have: on - ó. p (1-p) n - a -1.m b= δ. 1-p /p e c = m/p } -------------------(7) n = b + b² + 4 c/ 2 n´ = 1/p n cor = n + n' ---------- (8) We have to use the correction n' when p has a value between 0,25 and 0,75. The greek letters delta represents in the present esse the unilateral limits of the Gaussean distribution for the three conventional limits of precision : 1,64; 2,33; and 3,09 respectively. h we are only interested in having at least one individual, and m becomes equal to zero, the formula reduces to : c= m/p o para a = 1 a = { b + b²}² = b² = δ2 1- p /p }-----------------(9) n = 1/p n (cor) = n + n´ 2) If p is smaller than 0,1 we may use table 1 in order to find the mean m of a Poisson distribution and determine. n = m: p C) Which is the minimun number of individuals necessary for distinguishing two frequencies p1 and p2? 1) When pl and p2 are values between 0,1 and 0,9 we have: n = { δ p1 ( 1-pi) + p2) / p2 (1 - p2) n= 1/p1-p2 }------------ (13) n (cor) We have again to use the unilateral limits of the Gaussean distribution. The correction n' should be used if at least one of the valors pl or p2 has a value between 0,25 and 0,75. A more complicated formula may be used in cases where whe want to increase the precision : n (p1 - p2) δ { p1 (1- p2 ) / n= m δ = δ p1 ( 1 - p1) + p2 ( 1 - p2) c= m / p1 - p2 n = { b2 + 4 4 c }2 }--------- (14) n = 1/ p1 - p2 2) When both pl and p2 are smaller than 0,1 we determine the quocient (pl-r-p2) and procure the corresponding number m2 of a Poisson distribution in table 2. The value n is found by the equation : n = mg /p2 ------------- (15) D) What is the minimun number necessary for distinguishing three or more frequencies, p2 p1 p3. If the frequecies pl p2 p3 are values between 0,1 e 0,9 we have to solve the individual equations and sue the higest value of n thus determined : n 1.2 = {δ p1 (1 - p1) / p1 - p2 }² = Fiim n 1.2 = { δ p1 ( 1 - p1) + p1 ( 1 - p1) }² } -- (16) Delta represents now the bilateral limits of the : Gaussean distrioution : 1,96-2,58-3,29. 2) No table was prepared for the relatively rare cases of a comparison of threes or more frequencies below 0,1 and in such cases extremely high numbers would be required. E) A process is given which serves to solve two problemr of informatory nature : a) if a special type appears in n individuals with a frequency p(obs), what may be the corresponding ideal value of p(esp), or; b) if we study samples of n in diviuals and expect a certain type with a frequency p(esp) what may be the extreme limits of p(obs) in individual farmlies ? I.) If we are dealing with values between 0,1 and 0,9 we may use table 3. To solve the first question we select the respective horizontal line for p(obs) and determine which column corresponds to our value of n and find the respective value of p(esp) by interpolating between columns. In order to solve the second problem we start with the respective column for p(esp) and find the horizontal line for the given value of n either diretly or by approximation and by interpolation. 2) For frequencies smaller than 0,1 we have to use table 4 and transform the fractions p(esp) and p(obs) in numbers of Poisson series by multiplication with n. Tn order to solve the first broblem, we verify in which line the lower Poisson limit is equal to m(obs) and transform the corresponding value of m into frequecy p(esp) by dividing through n. The observed frequency may thus be a chance deviate of any value between 0,0... and the values given by dividing the value of m in the table by n. In the second case we transform first the expectation p(esp) into a value of m and procure in the horizontal line, corresponding to m(esp) the extreme values om m which than must be transformed, by dividing through n into values of p(obs). F) Partial and progressive tests may be recomended in all cases where there is lack of material or where the loss of time is less importent than the cost of large scale experiments since in many cases the minimun number necessary to garantee the results within the limits of precision is rather large. One should not forget that the minimun number really represents at the same time a maximun number, necessary only if one takes into consideration essentially the disfavorable variations, but smaller numbers may frequently already satisfactory results. For instance, by definition, we know that a frequecy of p means that we expect one individual in every total o(f1-p). If there were no chance variations, this number (1- p) will be suficient. and if there were favorable variations a smaller number still may yield one individual of the desired type. r.nus trusting to luck, one may start the experiment with numbers, smaller than the minimun calculated according to the formulas given above, and increase the total untill the desired result is obtained and this may well b ebefore the "minimum number" is reached. Some concrete examples of this partial or progressive procedure are given from our genetical experiments with maize.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

El present estudi es centra en els programes d’activitat física adreçats a persones grans en situació de dependència, que es esenvolupen en grup i que utilitzen el moviment actiu com a principal eina de treball. Es tracta d’una recerca que, per una banda, estudia i analitza les bases teòriques que avalen la importància i la necessitat de l’aplicació d’aquest tipus de programes. Per l’altra, justifica i defineix, amb detall, les línies directrius que han de guiar el seu desenvolupament i la seva aplicació en l’àmbit d’institucions d’atenció a les persones grans (residències, centres de dia i centres sòciosanitaris). El marc conceptual (capítol II) es construeix a partir d’una àmplia recerca bibliogràfica sobre les quatre dimensions d’anàlisi clau (l’envelliment, la dependència, l’atenció a les persones grans i l’activitat física) que fonamenta i justifica la proposta de programa que es fa en la segona part (capítol III). En aquesta es defineixen els referents, les finalitats, els objectius, els recursos que es poden utilitzar, les indicacions bàsiques per a organitzar el treball, els aspectes metodològics essencials per a l’aplicació del programa i les condicions necessàries per a poder-lo implementar. El resultat de tot el procés de recerca i estudi permet dir que, a nivell teòric, l’activitat física és una eina útil, eficaç i amb moltes possibilitats cara a l’atenció a les persones grans en situació de dependència. Que els esmentats programes han de ser fruit d’un procés de planificació, han de considerar les diferents dimensions de l’ésser en interacció constant, han de ser aplicats donant més importància al procés que al producte i que els recursos disponibles s’han d’utilitzar d’acord amb aquests plantejaments. En les línies de futur per a aquesta recerca, es planteja la seva continuació a partir de l’aplicació del programa VAFiD en diferents grups i la seva avaluació (seguint el model d’avaluació responent de Robert Stake) per determinar-ne la coherència i la qualitat.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The sensitivity of altitudinal and latitudinal tree-line ecotones to climate change, particularly that of temperature, has received much attention. To improve our understanding of the factors affecting tree-line position, we used the spatially explicit dynamic forest model TreeMig. Although well-suited because of its landscape dynamics functions, TreeMig features a parabolic temperature growth response curve, which has recently been questioned. and the species parameters are not specifically calibrated for cold temperatures. Our main goals were to improve the theoretical basis of the temperature growth response curve in the model and develop a method for deriving that curve's parameters from tree-ring data. We replaced the parabola with an asymptotic curve, calibrated for the main species at the subalpine (Swiss Alps: Pinus cembra, Larix decidua, Picea abies) and boreal (Fennoscandia: Pinus sylvestris, Betula pubescens, P. abies) tree-lines. After fitting new parameters, the growth curve matched observed tree-ring widths better. For the subalpine species, the minimum degree-day sum allowing, growth (kDDMin) was lowered by around 100 degree-days; in the case of Larix, the maximum potential ring-width was increased to 5.19 mm. At the boreal tree-line, the kDDMin for P. sylvestris was lowered by 210 degree-days and its maximum ring-width increased to 2.943 mm; for Betula (new in the model) kDDMin was set to 325 degree-days and the maximum ring-width to 2.51 mm; the values from the only boreal sample site for Picea were similar to the subalpine ones, so the same parameters were used. However, adjusting the growth response alone did not improve the model's output concerning species' distributions and their relative importance at tree-line. Minimum winter temperature (MinWiT, mean of the coldest winter month), which controls seedling establishment in TreeMig, proved more important for determining distribution. Picea, P. sylvestris and Betula did not previously have minimum winter temperature limits, so these values were set to the 95th percentile of each species' coldest MinWiT site (respectively -7, -11, -13). In a case study for the Alps, the original and newly calibrated versions of TreeMig were compared with biomass data from the National Forest Inventor), (NFI). Both models gave similar, reasonably realistic results. In conclusion, this method of deriving temperature responses from tree-rings works well. However, regeneration and its underlying factors seem more important for controlling species' distributions than previously thought. More research on regeneration ecology, especially at the upper limit of forests. is needed to improve predictions of tree-line responses to climate change further.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Debido al gran número de transistores por mm2 que hoy en día podemos encontrar en las GPU convencionales, en los últimos años éstas se vienen utilizando para propósitos generales gracias a que ofrecen un mayor rendimiento para computación paralela. Este proyecto implementa el producto sparse matrix-vector sobre OpenCL. En los primeros capítulos hacemos una revisión de la base teórica necesaria para comprender el problema. Después veremos los fundamentos de OpenCL y del hardware sobre el que se ejecutarán las librerías desarrolladas. En el siguiente capítulo seguiremos con una descripción del código de los kernels y de su flujo de datos. Finalmente, el software es evaluado basándose en comparativas con la CPU.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

L’organització educativa en una escola de música és un aspecte de l’àmbit de coneixement pedagògic que té el seu propi engranatge i un funcionament particular. Mitjançant l’estudi comparatiu entre les escoles municipals de música de Mataró, Olesa de Montserrat i “El Faristol” de Roda de Ter i Santa Maria del Corcó-L’Esquirol, aquest projecte vol donar una visió general de l’organització dels centres de règim especial d’àmbit musical, tot establint les bases teòriques per poder comprendre l’organització educativa de les escoles de música i analitzant tres grans àrees de gestió: el model educatiu, els recursos i el sistema relacional.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

La tesi doctoral titulada "La Dinàmica de les Pràctiques Científiques des d'un punt de vista experiencialista" té com a objectiu oferir una alternativa a les tesis de Kuhn defensades a l'"Estructura de les Revolucions Científiques". En aquest sentit, s'utilitzaran diferents experiments i models teòrics actuals en l'àmbit de les ciències cognitives per tal de superar la teoria estructuralista de la cognició, quee Kuhn proposa com la base de la seva filosofia de la ciència. Contràriament a aquesta teoria, l'experiencialisme se situa lluny de les tesis estructuralistes, en la mesura en què assumeix que la cognició humana emergeix des de la dinàmica interactiva dels agents cognitius humans entre ells en un entorn material, en tant que agents corporals. A partir d'aquesta interacció dinàmica, l'ésser humà genera un horitzó de sentit. Ja que la interacció entre els éssers humans en un entorn cultural i material és complex, dinàmic i canviant, la generació de sentit emergent no és com una estructura semàntica, coherent i sistemàtica, sinó que ha de ser considerada com un conjunt asistemàtic de perspectives exploratòries que se succeeixen en el temps, en funció dels diferents contextos i propòsits que un agent corporal porta a terme al llarg de la seva interacció dinàmica i temporal amb l'entorn. Com a resultat de tot això, els èssers humans apliquen diferents criteris interactius que donen lloc a diferents perspectives per categoritzar o estructurar el món material i cultural. Aquest punt de vista és completament diferent del kuhnià, donat que el segon argumenta que cada èsser humà té la seva pròpia Gestalt o estructura semàntica que projecta "a priori" sobre la realitat. Aquesta diferència serà molt important no només des d'un punt de vista teòric, sinó també des d'un punt de vista pràctic. Per exemple, s'argumentarà que en l'àmbit de la didàctica de les ciències empíriques, es poden produir canvis beneficiosos significatius si s'utilitzen tesis extretes del model experiencialista de la cognició humana, i es deixen de banda el cognitivisme i el teoreticisme, que són actualment les bases teòriques de la manera en qué funciona l'educació científica. Finalment, conclourem afirmant que la visió experiencialista de la cognició implica assumir una forta relació entre l'ètica i la ciència, puix que els èssers humans són capaços d'utilitzar diferents criteris interactius per explorar la realitat i, per tant, sempre poden buscar millors estragègies per entendre's els uns amb els altres.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Proyecto Delta es una iniciativa escenográfica de un programa de concierto específico constituido con obras de música contemporánea. La propuesta se lleva a cabo gracias a un fundamento teórico que incluye reflexiones en torno a las figuras comprometidas en el acto musical escénico: intérprete, obra y público. En esta digresión sus funciones son objeto de un desfiguramiento, fomentando la capacidad creativa del intérprete como director artístico. El concierto se convierte, de este modo, en un producto acabado. En particular, el Proyecto Delta se construye sobre el diálogo entre lo sonoro y lo visual, lo audible y lo visible: la música y el espacio.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Aquesta recerca té com a objecte d'estudi la utilització dels mitjans de comunicació per a finalitats polítiques i intenta analitzar la relació que els polítics professionals mantenen amb els mitjans i com aquests poden ser importants dins d'un procés polític-electoral i per a la formació de l'opinió pública. El nostre objectiu general és, entre d’altres, analitzar l'estructura d’aquests mitjans i grups polítics i descriure com estan situats, utilitzant com a exemple l'estat del Rio Grande do Norte (RN), al Nord-est de Brasil. Partint de les preguntes, ¿a qui pertanyen els mitjans de comunicació i qui té el poder d'informar en l'aquest Estat? anem construïm el marc teòric, analitzant el monopoli i oligopoli en la comunicació a Brasil, especialment a la radiodifusió, en la qual hi ha una gran concentració de concessions públiques en propietat dels polítics professionals amb mandats electius i/o de grups partidaris, què pot ser anomenat de ‘coronelismo electrònic’

Relevância:

60.00% 60.00%

Publicador:

Resumo:

This Article breaks new ground toward contractual and institutional innovation in models of homeownership, equity building, and mortgage enforcement. Inspired by recent developments in the affordable housing sector and other types of public financing schemes, we suggest extending institutional and financial strategies such as time- and place-based division of property rights, conditional subsidies, and credit mediation to alleviate the systemic risks of mortgage foreclosure. Two new solutions offer a broad theoretical basis for such developments in the economic and legal institution of homeownership: a for-profit shared equity scheme led by local governments alongside a private market shared equity model, one of "bootstrapping home buying with purchase options".

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Extinction, recolonization, and local adaptation are common in natural spatially structured populations. Understanding their effect upon genetic variation is important for systems such as genetically modified organism management or avoidance of drug resistance. Theoretical studies on the effect of extinction and recolonization upon genetic variance started appearing in the 1970s, but the role of local adaptation still has no good theoretical basis. Here we develop a model of a haploid species in a metapopulation in which a locally adapted beneficial allele is introduced. We study the effect of different spatial patterns of local adaptation, and different metapopulation dynamics, upon the fixation probability of the beneficial allele. Controlling for the average selection pressure, we find that a small area of positive selection can significantly increase the global probability of fixation. However, local adaptation becomes less important as extinction rate increases. Deme extinction and recolonization have a spatial smoothing effect that effectively reduces spatial variation in fitness.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Summary: The theoretical basis of syntax

Relevância:

60.00% 60.00%

Publicador:

Resumo:

En este documento se realiza una descripción de los trastornos de identidad de género (TIG) y de su situación a nivel nacional e internacional, teniendo en cuenta la legislación y epidemiología, con el objetivo de consolidar así una base teórica para el estudio. Se diferencian también otras patologías similares para evitar confusión o errores. Se propone un estudio cuantitativo, observacional, transversal, descriptivo y correlacional que tiene como objetivos principales evaluar los conocimientos, habilidades y actitudes necesarios del personal de enfermería para el cuidado de las personas con TIG y comparar las competencias de la enfermería de distintos niveles asistenciales. Como método de recogida de datos se utiliza un cuestionario de elaboración propia, de preguntas cerradas con múltiples opciones de respuesta. El análisis de los datos será inferencial y descriptivo, ya que el objetivo es realizar una estimación a partir de los resultados obtenidos de la muestra sobre el conjunto total de la población con la finalidad de realizar el contraste de la hipótesis formulada; para ello, se realizará la prueba no paramétrica de Chi-­‐ cuadrado.