928 resultados para Non-perturbative methods


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Obesity is the most common nutritional problem in dogs and it can cause various harmful effects on animal health. However, the effect of this condition on systolic blood pressure (SBP) in obese dogs is controversial. The indirect method of measuring PAS is the most commonly used in veterinary medicine for the diagnosis of systemic hypertension, because it is more practical and easy to access. There is little scientific information about the comparison of the two non- invasive methods of measurement of blood pressure in obese dogs. Therefore, the objective of this study was to evaluate the SBP in obese dogs by comparing both indirect methods of measuring blood pressure, with oscillometric and doppler vascular in order to verify the differences in blood pressure values, but also the best method to assess the SBP dogs in this body score condition. The study complain blood pressure measurement of 50 dogs, with were divided in obese dogs with mean body condition score (BCS) of 8.42 +/- 0.50 (n = 25) and dogs with ideal BCS of 4.56 +/- 0.51 (n = 25). At comparison of blood pressure values, SBP values obtained by doppler method (152 +/- 16mmHg) were higher than the oscillometric (136 +/- 11mmHg). Correspondence analysis determined by multivariate statistical analysis showed correlation between body condition and the procedure of the SBP. These findings suggest that the indirect method doppler can better reflect the SBP in obese dogs.

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Pós-graduação em Física - IFT

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Prairie dog (Cynomys ludovicianus) control has historically consisted of lethal methods to maintain, reduce, or eliminate populations in South Dakota and throughout the species range. Non-lethal methods of control are desired to meet changing management objectives for the black-tailed prairie dog. The use of naturally occurring buffer strips as vegetative barriers may be effective in limiting prairie dog town expansion. The objectives of this study were: 1) to evaluate effective width of vegetative barriers in limiting prairie dog towns expansion in western South Dakota; and 2) to document effect native vegetation height on expansion of prairie dog towns in western South Dakota. Five study sites were established in western South Dakota on rangelands containing prairie dog towns of adequate size. Electric fences were constructed for the purpose of excluding cattle and creating buffer strips of native grasses and shrubs. Prairie dogs were poisoned to create a prairie dog free buffer zone adjacent to active prairie dog towns. Grazing was allowed on both sides of the buffer strip. When grazing pressure was not sufficient, mowing was used to simulate grazing. Buffer strips were 100 meters long and 10, 25, and 40 meters in width. A zero meter control was included on all study sites. Quadrats (25) were randomly distributed throughout the buffer strips. Evaluation of study sites included visual obstruction, vegetation cover, vegetation frequency, vegetation height, and vegetation identification. Barrier penetration was evaluated by the presence of new active burrows behind vegetative barriers. Significant relationships were documented for both VOR and vegetation height. No significant difference was found between frequency of breakthroughs and buffer widths.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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We estimate the masses of the 1(--) heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in alpha(s) but including non-perturbative terms up to the complete dimension-six condensate contributions. This approach allows to fix more precisely the value of the QCD continuum threshold (often taken ad hoc) at which the optimal result is extracted. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. We also study the effects of the heavy quark mass definitions on these LO results. The SU(3) mass-splittings of about (50-110) MeV and the ones of about (250-300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavor independent. The mass predictions summarized in Table 4 are compared with the ones in the literature (when available) and with the three Y-c(4260, 4360, 4660) and Y-b(10890) 1(--) experimental candidates. We conclude (to this order approximation) that the lowest observed state cannot be a pure 1(--) four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0(++) four-quark and molecule states which are about (0.5-1) GeV heavier than the corresponding 1(--) states, while the splittings between the 0(++) lowest ground state and the 1st radial excitation is about (300-500) MeV. We complete the analysis by estimating the decay constants of the 1(--) and 0(++) four-quark states which are tiny and which exhibit a 1/M-Q behavior. Our predictions can be further tested using some alternative non-perturbative approaches or/and at LHCb and some other hadron factories. (c) 2012 Elsevier B.V. All rights reserved.

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The fall of the Berlin Wall opened the way for a reform path – the transition process – which accompanied ten former Socialist countries in Central and South Eastern Europe to knock at the EU doors. By the way, at the time of the EU membership several economic and structural weaknesses remained. A tendency towards convergence between the new Member States (NMS) and the EU average income level emerged, together with a spread of inequality at the sub-regional level, mainly driven by the backwardness of the agricultural and rural areas. Several progresses were made in evaluating the policies for rural areas, but a shared definition of rurality is still missing. Numerous indicators were calculated for assessing the effectiveness of the Common Agricultural Policy and Rural Development Policy. Previous analysis on the Central and Eastern European countries found that the characteristics of the most backward areas were insufficiently addressed by the policies enacted; the low data availability and accountability at a sub-regional level, and the deficiencies in institutional planning and implementation represented an obstacle for targeting policies and payments. The next pages aim at providing a basis for understanding the connections between the peculiarities of the transition process, the current development performance of NMS and the EU role, with particular attention to the agricultural and rural areas. Applying a mixed methodological approach (multivariate statistics, non-parametric methods, spatial econometrics), this study contributes to the identification of rural areas and to the analysis of the changes occurred during the EU membership in Hungary, assessing the effect of CAP introduction and its contribution to the convergence of the Hungarian agricultural and rural. The author believes that more targeted – and therefore efficient – policies for agricultural and rural areas require a deeper knowledge of their structural and dynamic characteristics.

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„Risikomaße in der Finanzmathematik“ Der Value-at -Risk (VaR) ist ein Risikomaß, dessen Verwendung von der Bankenaufsicht gefordert wird. Der Vorteil des VaR liegt – als Quantil der Ertrags- oder Verlustverteilung - vor allem in seiner einfachen Interpretierbarkeit. Nachteilig ist, dass der linke Rand der Wahrscheinlichkeitsverteilung nicht beachtet wird. Darüber hinaus ist die Berechnung des VaR schwierig, da Quantile nicht additiv sind. Der größte Nachteil des VaR ist in der fehlenden Subadditivität zu sehen. Deswegen werden Alternativen wie Expected Shortfall untersucht. In dieser Arbeit werden zunächst finanzielle Risikomaße eingeführt und einige ihre grundlegenden Eigenschaften festgehalten. Wir beschäftigen uns mit verschiedenen parametrischen und nichtparametrischen Methoden zur Ermittlung des VaR, unter anderen mit ihren Vorteilen und Nachteilen. Des Weiteren beschäftigen wir uns mit parametrischen und nichtparametrischen Schätzern vom VaR in diskreter Zeit. Wir stellen Portfoliooptimierungsprobleme im Black Scholes Modell mit beschränktem VaR und mit beschränkter Varianz vor. Der Vorteil des erstens Ansatzes gegenüber dem zweiten wird hier erläutert. Wir lösen Nutzenoptimierungsprobleme in Bezug auf das Endvermögen mit beschränktem VaR und mit beschränkter Varianz. VaR sagt nichts über den darüber hinausgehenden Verlust aus, während dieser von Expected Shortfall berücksichtigt wird. Deswegen verwenden wir hier den Expected Shortfall anstelle des von Emmer, Korn und Klüppelberg (2001) betrachteten Risikomaßes VaR für die Optimierung des Portfolios im Black Scholes Modell.

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Il pomodoro è una delle colture principali del panorama agro-alimentare italiano e rappresenta un ingrediente base della tradizione culinaria nazionale. Il pomodoro lavorato dall’industria conserviera può essere trasformato in diverse tipologie merceologiche, che si differenziano in base alla tecniche di lavorazione impiegate ed alle caratteristiche del prodotto finito. la percentuale di spesa totale destinata all’acquisto di cibo fuori casa è in aumento a livello globale e l’interesse dell’industria alimentare nei confronti di questo canale di vendita è quindi crescente. Mentre sono numerose le indagine in letteratura che studiano i processi di acquisto dei consumatori finali, non ci sono evidenze di studi simili condotti sugli operatori del Food Service. Obiettivo principale della ricerca è quello di valutare le preferenze dei responsabili acquisti del settore Food Service per diverse tipologie di pomodoro trasformato, in relazione ad una gamma di attributi rilevanti del prodotto e di caratteristiche del cliente. La raccolta dei dati è avvenuta attraverso un esperimento di scelta ipotetico realizzato in Italia e alcuni mercati esteri. Dai risultati ottenuti dall’indagine emerge che i Pelati sono la categoria di pomodoro trasformato preferita dai responsabili degli acquisti del settore Food Service intervistati, con il 35% delle preferenze dichiarate nell'insieme dei contesti di scelta proposti, seguita dalla Polpa (25%), dalla Passata (20%) e dal Concentrato (15%). Dai risultati ottenuti dalla stima del modello econometrico Logit a parametri randomizzati è emerso che alcuni attributi qualitativi di fiducia (credence), spesso impiegati nelle strategie di differenziazione e posizionamento da parte dell’industria alimentare nel mercato Retail, possono rivestire un ruolo importante anche nell’influenzare le preferenze degli operatori del Food Service. Questo potrebbe quindi essere un interessante filone di ricerca da sviluppare nel futuro, possibilmente con l'impiego congiunto di metodologie di analisi basate su esperimenti di scelta ipotetici e non ipotetici.

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Im Rahmen des A4-Experiments werden die Beiträge des Strange-Quarks zu den elektromagnetischen Formfaktoren des Protons gemessen. Solche Seequarkeffekte bei Niederenergieobservablen sind für das Verständnis der Hadronenstruktur wichtig, denn sie stellen eine direkte Manifestation der QCD-Freiheitsgrade im nichtperturbativen Bereich dar.rnrnLinearkombinationen der Strangeness-Vektorformfaktoren des Protons $G_E^s$ und $G_M^s$ sind experimentell über die Messung der paritätsverletzenden Asymmetrie im Wirkungsquerschnitt der elastischen Streuung longitudinal polarisierter Elektronen an unpolarisierten Nukleonen zugänglich. Vor dieser Arbeit hatte die A4-Kollaboration zwei solche Messungen unter Vorwärtsstreuwinkeln bei den Viererimpulsübertägen $Q^2$ von jeweils 0.23 und 0.10 (GeV/c)$^2$ veröffentlicht. Um die Separation von $G_E^s$ und $G_M^s$ beim höheren $Q^2$-Wert zu erhalten, wurde eine Messung unter Rückwärtswinkeln mit der Strahlenergie von 315 MeV durchgeführt.rnrnIm A4-Experiment werden die an einem Flüssigwasserstoff-Target gestreuten Elektronen eines longitudinal polarisierten Strahls mit einem Cherenkov-Kalorimeter einzeln gezählt. Durch die kalorimetrische Energiemessung erfolgt die Trennung der elastischen von den inelastischen Ereignissen. Bei Rückwärtswinkeln wurde dieses Apparat mit einem Szintillator als Elektronentagger erweitert, um den $\gamma$-Untergrund aus dem $\pi^0$-Zerfall zu unterdrücken.rnrnUm die Auswertung dieser Messung zu ermöglichen, wurden im Rahmen dieser Arbeit die gemessenen Energiespektren anhand von ausführlichen Simulationen der Streuprozesse und des Antwortverhaltens der Detektoren untersucht, und eine Methode zur Behandlung des restlichen Untergrunds aus der $\gamma$-Konversionrnvor dem Szintillator entwickelt. Die Simulationergebnisse sind auf dem 5%-Niveau mit den Messungen verträglich, und es wurde bewiesen, dass die Methode der Untergrundbehandlung anwendbar ist.rnrnDie Asymmetriemessung bei Rückwärtswinkeln, die man nach Anwendung der hier erarbeiteten Untergrundbehandlung erhält, wurde für die Separation von $G_E^s$ und $G_M^s$ bei $Q^2$=0.22 (GeV/c)^2 mit der Vorwärtswinkelmessung beim selbenrn$Q^2$ kombiniert. Es ergeben sich die Werte:rnrn$G_M^s$= -0.14 ± 0.11_{exp} ± 0.11_{theo} undrn$G_E^s$= 0.050 ± 0.038_{exp} ± 0.019_{theo}, rnrnwobei die systematische Unsicherheit wegen der Untergrundbehandlung im experimentellen Fehler enthalten ist. Am Ende der Arbeit werden die aus diesen Resultaten folgenden Rückschlüsse auf den Einfluss der Strangeness auf die statischen elektromagnetischen Eigenschaften des Protons diskutiert.rn

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The electromagnetic form factors of the proton are fundamental quantities sensitive to the distribution of charge and magnetization inside the proton. Precise knowledge of the form factors, in particular of the charge and magnetization radii provide strong tests for theory in the non-perturbative regime of QCD. However, the existing data at Q^2 below 1 (GeV/c)^2 are not precise enough for a hard test of theoretical predictions.rnrnFor a more precise determination of the form factors, within this work more than 1400 cross sections of the reaction H(e,e′)p were measured at the Mainz Microtron MAMI using the 3-spectrometer-facility of the A1-collaboration. The data were taken in three periods in the years 2006 and 2007 using beam energies of 180, 315, 450, 585, 720 and 855 MeV. They cover the Q^2 region from 0.004 to 1 (GeV/c)^2 with counting rate uncertainties below 0.2% for most of the data points. The relative luminosity of the measurements was determined using one of the spectrometers as a luminosity monitor. The overlapping acceptances of the measurements maximize the internal redundancy of the data and allow, together with several additions to the standard experimental setup, for tight control of systematic uncertainties.rnTo account for the radiative processes, an event generator was developed and implemented in the simulation package of the analysis software which works without peaking approximation by explicitly calculating the Bethe-Heitler and Born Feynman diagrams for each event.rnTo separate the form factors and to determine the radii, the data were analyzed by fitting a wide selection of form factor models directly to the measured cross sections. These fits also determined the absolute normalization of the different data subsets. The validity of this method was tested with extensive simulations. The results were compared to an extraction via the standard Rosenbluth technique.rnrnThe dip structure in G_E that was seen in the analysis of the previous world data shows up in a modified form. When compared to the standard-dipole form factor as a smooth curve, the extracted G_E exhibits a strong change of the slope around 0.1 (GeV/c)^2, and in the magnetic form factor a dip around 0.2 (GeV/c)^2 is found. This may be taken as indications for a pion cloud. For higher Q^2, the fits yield larger values for G_M than previous measurements, in agreement with form factor ratios from recent precise polarized measurements in the Q2 region up to 0.6 (GeV/c)^2.rnrnThe charge and magnetic rms radii are determined as rn⟨r_e⟩=0.879 ± 0.005(stat.) ± 0.004(syst.) ± 0.002(model) ± 0.004(group) fm,rn⟨r_m⟩=0.777 ± 0.013(stat.) ± 0.009(syst.) ± 0.005(model) ± 0.002(group) fm.rnThis charge radius is significantly larger than theoretical predictions and than the radius of the standard dipole. However, it is in agreement with earlier results measured at the Mainz linear accelerator and with determinations from Hydrogen Lamb shift measurements. The extracted magnetic radius is smaller than previous determinations and than the standard-dipole value.