65,306 research outputs found

    Prospects for measuring |Vts| at the LHC

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    36th International Conference on High Energy Physics, July 4-11, 2012 Melbourne, AustraliaWe study the prospects of measuring the CKM matrix element |Vts| at the LHC with the top quarks produced in the processes pp → ttXÂŻ and pp → t/tXÂŻ , and the subsequent decays t → W+s and tÂŻ → W−sÂŻ. To reduce the jet activity in top quark decays, we insist on tagging the W± leptonically, W± → ` ±Μ` (` = e,”, τ), and analyse the anticipated jet profiles in the signal process t → W s and the dominant background from the decay t → W b. To that end, we analyse the V0 (K 0 and Λ) distributions in the s- and b-quark jets concentrating on the energy and transverse momentum distributions of these particles. Noting that the V0s emanating from the t → W b branch have displaced decay vertexes from the interaction point due to the weak decays b → c → s, and that the b-quark jets are rich in charged leptons, the information from the secondary vertex distributions and the absence of energetic charged leptons in the jet provide additional (b-jet vs. s-jet) discrimination in top quark decays. These distributions are used to train a boosted decision tree (BDT), a technique used successfully in measuring the CKM matrix element |Vtb| in single top production at the Tevatron. We show that the BDT-response functions corresponding to the signal (t →W s) and background (t →W b) are very different. Detailed simulations undertaken by us with the Monte Carlo generator PYTHIA are used to estimate the background rejection versus signal efficiency for two representative LHC energies √ s = 7 TeV and 14 TeV. We argue that a benchmark with 5% signal (t → W s) efficiency and a background (t → bW ) rejection by a factor 103 (required due to the anticipated value of the ratio |Vts| 2/|Vtb| 2 ' 1.6×10−3 ) can be achieved at the LHC, given the promised luminosit

    Spatial effects on the aggregate demand

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    This paper analyses if several spatial variables coming from cities and transportation system can affect the money market, specially the income velocity of circulation. The specification of the theoretical model include the income velocity of circulation into the IS-LM multipliers. Considering the Baumol-Tobin model for transaction money demand, the Central Place Theory, and some gravity models, we can conclude that the incom velocity of circulation and the supply money in monetary terms are dependent, among others, of seven spatial variables such as the country first city population, the population density, the passenger-kilometers transported by railways, and several ratios referred to some geographical variables. The model has been applied across 64 countries during the period 1978-1997. Panel data techniques has been used for estimating the model. Thresults indicate that most of the explanatory variables are significant on income velocity of circulation and the money supply. The macroeconomic equilibriunm is affected by the spatial explanatory variables because these last affect the LM curve, an hence prices and output level maybe influenced because of that.

    Spatial Effects on the Aggregate Demand

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    The main aim of this paper is to analyse if determined variables related with transportation, demography and geography can cause fluctuations in the aggregate demand function and hence affect the prices,employment and output levels in an economy.The panel data to carry out this analysis includes 64 countries (19 european, 14 african, 17 asian, 14 american) during 21 years (1978-98).The specification of the model is based in to relate the Baumol-Tobin model for demand money transaction, with the central places theory for obtaining a relationship between money velocity and variables such as population density, passenger-kilometers and net tons-kilometers transported by railway, the first city population, and several ratios corresponding with road transportation. Panel data techniques have been aplyed and estimation results indicate that all explanatory variables are significant and all cause Granger on money velocity during this period. Unit roots test of Harris-Tzavalis and cointegration test of Chiwa Kao notify that the relationship between money velocity and this explanatory variables is not spurious and it is a long run relation. But money velocity at long run is a component of the slope of LM curve, and hence fluctuations in the explanatory variables can cause movements in the LM curve and in the aggregate demand function affecting the output level and prices.

    Spatial effects on technical progress: growth, and convergence among countries

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    This paper analyses how several spatial variables coming from cities and transportation system can affect money market, specially the income velocity of circulation, assuming an unit-elastic aggregate demand function and considering money velocity as a variable. Fluctuations in velocity caused by some spatial variables, under certain conditions, can affect the aggregate demand curve. The specification of the main relation-ship has found in the Baumol-Tobin model for transaction money demand, and in Christaller-Lösch central place theory. The estimation of the model has been based on panel data techniques and applied across 61 countries during 14 years in the 1978-1991 period. Theoretical and econometric results indicates that seven spatial variables like the country’s first city population, the population density, the passengers-kilometer transported by railways, and several ratios referred to some geographical variables, can provokes fluctuations on aggregate demand curve in the short run. In the long run, the aggregate supply can be also affected by means of these variables. In order to checking this question, considering that these spatial variables are not product factor, we propose to observe if these variables can affect the technological progress coefficient, A, concerning to an aggregate production function, according to a neo-classical growth model. Results by means of the Mankiw, Romer and Weil method, and also by means of an endogenous growth model of technology diffusion, indicates that some spatial variables affect the speed of convergence relative to the real per head income, across these 61 countries. However, a certain amount in some of these variables generates a congestion process in some countries. For checking it, we utilize a Barro and Sala i Martin endogenous growth model which reflects government activities. The concluding remarks indicates that some of these spatial variables above mentioned increases the speed of convergence but generates congestion in some countries. These spatial variables also affect the aggregate supply, and hence the price and output levels. Key words: transportation, regional growth, convergence, congestion. JEL Class.: R41

    Quality capital and economic growth

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    The productivity generated by capital goods is not uniform, specially over the time. The productivity obtained from phisical goods is minor than one generated by new capital goods, or quality capital goods. It seems that the difference between both kinds of capital stems from the fact that vintage capital is affected by an additional form of technical progress. When capital is affected by this kind of technical progress, it is so-called capital jelly from Solow (1960). There are hence two possible forms of understand technical progress: the classical one or, alternatively, this new class of technical progress tath affects only to capital. Both kinds of technical progress affect growth in two separate ways, and for this reason it is interesting to develop a special analysis on the investment in capital goods in order to identify what is the difference between the productivity derived from physical capital and from vintage capital. The main aim of this paper is to analyse how two types of technical progress affcet the real income growth rate in the countries belonging to three world areas: North America, the Euro zone, and some countries of the Pacific Rim, during the period 1960-2000. Precursory works of the present research have found in Hulten (1992), Greenwood, Hercowitz and Krusell (1997), Gordon (1999) and Hobijn (2000).

    La obra de Henry Mackenzie y las secuencias tĂ­picas de la narrativa sentimental

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    El miembro de la IlustraciĂłn escocesa Henry Mackenzie es autor de tres novelas de las cuales la primera, The Man of Feeling, alcanza un Ă©xito considerable dentro de la moda cultural del sentimentalismo britĂĄnico. Nos interesa la definiciĂłn de ciertos motivos temĂĄticos y narrativos centrales en esta Ă©poca y esta cultura: la benevolencia del hombre sentimental, el engaño del que es a menudo vĂ­ctima, la seducciĂłn trĂĄgica de una heroĂ­na virtuosa a cargo de un villano libertino y la seducciĂłn protagonizada por estos mismos personajes tĂ­picos con un final feliz. Tales temas y tramas son centrales en la obra de Mackenzie y solamente a partir de ellos se puede articular el mundo de sus tres novelas y sus relatos mĂĄs cĂ©lebres. Por tanto, Mackenzie ha sido visto como la quintaesencia de lo sentimental. En sus temas y tipos se resume un cierto concepto de virtud (para el que utilizaremos el concepto de “ideologema”) propio de la narrativa de esta Ă©poca y corriente cultural.The Scottish Enlightenment writer Henry Mackenzie is the author of three novels, the first of which, The Man of Feeling, achieves a notable success in the cultural trend of British sentimentalism. We are interested in certain narrative and thematic motives which are central to this age and this culture: the benevolence of the man of feeling, the fraud to which he is often a victim, the tragical seduction of a heroine by a libertine villain and the variant of the same plot, protagonized by the same type characters but with a happy ending. Such plots and types are central in Mackenzie and only through them is built the microcosmos of his novels and his most famous short stories. Consequently, Mackenzie’s work has been seen as quintessentially sentimental. In his themes and plots is comprehended a certain notion of virtue (we will use for it the concept of "idelogeme”) which characterizes the narrative of this age and this cultural trend

    Technical progress effects on productivity and growth in the Commonwealth of Nations (1993-2009)

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    ABSTRACT. The productivity generated by capital goods is not uniform along the time. When there exist conventional physical capital goods the productivity obtained is minor that the one generated by quality capital goods. To obtain a correct measure of growth in presence of this embodied technical progress there exist three schools: first, the traditional growth accounting school appears due to limitations existing in the measures in efficiency units of the quality of the real investment, because of the investment is not really comparable along the time. The analysis is based in to adjust the quality or productivity of the investment goods constructing hedonic prices indices. This school is represented among others by Hulten (1992), Jovanovic and Nyarko (1996), Bartelsman and Dhrymes (1998), and Gordon (1999). The second school analyzes the productivity using longitudinal micro-level data sets. The most important contributions of this school are Griliches and Ringstad (1971), Olley and Pakes (1996), Caves (1998), McGuckin and Stiroh (1999), and Tybout (2000). The third school is the equilibrium growth accounting school, which measures the balance growth by means of vintage capital models, being represented by Greenwood, Hercowitz and Krusell (1997), Campbell (1998), Hobijn (2000), and Comin (2002). The main aim of this paper is to analyze which are the effects of the two form of technical progress, neutral and directly embodied while capital is accumulated, on the economic growth and the labour productivity. The application has been made to compare the responsibility of the embodied technical progress on the economic growth and productivity during the period (1993-2009) in the most representative economies of the Commonwealth of Nations. The vintage capital model has been made taking quarterly and annual data to each country, coming from the OECD Statistics. We use multivariate time series and cointegration techniques, in special autoregressive integrated moving average and vector autoregressive models (VAR), and autoregressive distributed lags models (ARDL). Keywords: Endogenous technical progress, Vintage capital, Investment-specific technological change. JEL Class: O47, O57.

    Evolution of atmospheric connectivity in the 20th century

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    We aim to study the evolution of the upper atmosphere connectivity over the 20th century as well as to distinguish the oceanically forced component from the atmospheric internal variability. For this purpose we build networks from two different reanalysis data sets using both linear and nonlinear statistical similarity measures to determine the existence of links between different regions of the world in the two halves of the last century. We furthermore use symbolic analysis to emphasize intra-seasonal, intra-annual and inter-annual timescales. Both linear and nonlinear networks have similar structures and evolution, showing that the most connected regions are in the tropics over the Pacific Ocean. Also, the Southern Hemisphere extratropics have more connectivity in the first half of the 20th century, particularly on intra-annual and intra-seasonal timescales. Changes over the Pacific main connectivity regions are analyzed in more detail. Both linear and nonlinear networks show that the central and western Pacific regions have decreasing connectivity from early 1900 up to about 1940, when it starts increasing again until the present. The inter-annual network shows a similar behavior. However, this is not true of other timescales. On intra-annual timescales the minimum connectivity is around 1956, with a negative (positive) trend before (after) that date for both the central and western Pacific. While this is also true of the central Pacific on intra-seasonal timescales, the western Pacific shows a positive trend during the entire 20th century. In order to separate the internal and forced connectivity networks and to study their evolution through time, an ensemble of atmospheric general circulation model outputs is used. The results suggest that the main connectivity patterns captured in the reanalysis networks are due to the oceanically forced component, particularly on inter-annual timescales. Moreover, the atmospheric internal variability seems to play an important role in determining the intra-seasonal timescale networks

    Depositional evolution of La Parra karstic lake (Iberian Chain, Spain) during the last 1,600 years: climate and human impact implications

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    La laguna de La Parra (39o 50.948’, 1o 52’, 1014 m) es un lago pequeño relativamente profundo (Zmax = 17.5 m) de agua dulce, monomĂ­ctico y con morfologĂ­a circular (116 m diĂĄmetro). Forma parte de un complejo kĂĄrstico constituido por siete lagos situado en la Cordillera IbĂ©rica (Cuenca, este de España), originado en una dolina que interceptĂł el acuĂ­fero regional. El registro sedimentario de la zona mĂĄs profunda del lago se ha estudiado mediante tĂ©cnicas sedimentolĂłgicas, microscĂłpicas, geoquĂ­micas y fĂ­sicas. EstĂĄ constituido principalmente por sedimentos clĂĄsticos carbonatados, caracterizados por una gran variabilidad de facies sedimentarias que estĂĄn controladas por cambios en la entrada de detrĂ­ticos al sistema. Al mismo tiempo, estas fluctuaciones reflejan una amplia variabilidad hidrolĂłgica durante los Ășltimos 1600 años. El modelo cronolĂłgico de la secuencia sedimentaria se basa en 7 dataciones de 14C AMS. La historia sedimentaria de la laguna de La Parra comprende 5 etapas: (i) el comienzo de la sedimentaciĂłn lacustre hacia el año 300 DC; (ii) un lago somero que aumenta progresivamente su nivel durante la Baja Edad Media (500 – 900 DC); (iii) niveles del lago bajos, con aumento en los aportes detrĂ­ticos coincidiendo con la AnomalĂ­a ClimĂĄtica Medieval (ACM); (iv) un periodo con predominio de niveles altos del lago, pero algĂșn episodo de niveles bajos, con desarrollo de meromixis frecuente durante la Pequeña Edad del Hielo (PEH, 1400 . 1850 DC) y (v) un ligero aumento de los niveles del lago en tiempos recientes (1900 - actualidad), precedido por un periodo inicial de bajo nivel de agua a finales del siglo XIX. La principal afecciĂłn antrĂłpica en el lago y su entorno estĂĄ relacionada con cambios en el uso de la tierra durante la Edad Media debido a la agricultura y la transhumancia, lo que implicĂł un aumento en los aportes detrĂ­ticos al lago; y mĂĄs recientemente, con la extracciĂłn de aguas subterrĂĄneas del acuĂ­fero regional mediante pozosagrĂ­colas. Las fluctuaciones paleohidrolĂłgicas y paleoambientales de la laguna de La Parra son coherentes con otros registros paleoclimĂĄticos de la PenĂ­nsula IbĂ©rica, mostrando una fase mĂĄs ĂĄrida durante la ACM y mĂĄs hĂșmeda durante la PEH en el MediterrĂĄneo occidental. Este nuevo aporte refuerza la hipĂłtesis de un comportamiento antitĂ©tico este-oeste del clima en la region mediterrĂĄnea desde el 900 DC