Embeddings of SL(2,Z) into the Cremona group

Geometric and dynamic properties of embeddings of SL(2,Z) into the Cremona group are studied. Infinitely many non-conjugate embeddings which preserve the type (i.e. which send elliptic, parabolic and hyperbolic elements onto elements of the same type) are provided. The existence of infinitely many non-conjugate elliptic, parabolic and hyperbolic embeddings is also shown. In particular, a group G of automorphisms of a smooth surface S obtained by blowing-up 10 points of the complex projective plane is given. The group G is isomorphic to SL(2,Z), preserves an elliptic curve and all its elements of infinite order are hyperbolic.Comment: to appear in Transformation Group

Trust, Distrust and Economic Integration. Setting the Stage

© Cambridge University Press 2012. Introduction The concept of integration, the dependent variable of this study, has received different interpretations by lawyers, political scientists and economists. Lawyers generally understand the concept as referring to ‘legal integration’, which is defined as ‘the gradual penetration’ of EU law ‘into the domestic law of its member states’. Economists prefer the concept of ‘economic integration’, defined as ‘the elimination of economic frontiers between two or more economies’. The removal of trade impediments between participating nations and ‘the establishment of certain elements of cooperation and coordination between them’ characterize the process of economic integration, as opposed to other forms of international cooperation. Political scientists have been more reluctant to provide a ready-made definition of ‘integration’ and have focused their analysis on the ‘political context in which integration occurs’, the dependent variable being generally conceived in broad and descriptive terms as the transfer of authority to a supranational level. The relatively recent emergence of the concept of ‘integration’ owes a lot to functionalist theories, which were the first to break away from ‘the traditional link between authority and a definite territory by ascribing authority to activities based in areas of agreement’. States exercise several functions (activities), some of which require action at the international level. This transfer initiates the process of integration, which is driven by the continuous pursuit of these functions, in the context of an international institution created for that purpose. According to functionalism, ‘(e)very function is left to generate others gradually; in every case the appropriate authority is left to grow and develop out of actual performance.’ Based on this approach, neo-functionalism was able to construct a theory of regional integration employing the model of European integration as the archetypical paradigm of the concept. The functionalist approach and the concept of integration are profoundly interlinked: without the functionalist emphasis on the existence of separate functions, where authority can be transferred, there can be no integration, in the sense political scientists give to this term

Charge Radii of beta-Stable Nuclei

In previous work it was shown that the radius of nucleus R is determined by the alpha-cluster structure and can be estimated on the number of alpha-clusters disregarding to the number of excess neutrons. A hypothesis also was made that the radius R_m of a beta-stable isotope, which is actually measured at electron scattering experiments, is determined by the volume occupied by the matter of the core plus the volume occupied by the peripheral alpha-clusters. In this paper it is shown that the condition R_m = R restricts the number of excess neutrons filling the core to provide the beta-stability. The number of peripheral clusters can vary from 1 to 5 and the value of R for heavy nuclei almost do not change, whereas the number of excess neutrons should change with the number of peripheral clusters to get the value of R_m close to R. It can explain the path of the beta-stability and its width. The radii R_m of the stable isotopes with 12 =< Z =< 83 and the alpha-decay isotopes with 84 =< Z =< 116 that are stable to beta-decay have been calculated.Comment: Latex2e 2.09, 10 pages, 3 figure

Sound range-dependent propagation : An experiment on down-slope propagation over the Argentinian continental slope

A range dependent acoustic down-slope propagation loss (TL) experiment was conducted in 1989 over the Argentinian Continental Slope, along a 50 km track, using two TRACKER aircrafts from the AntiSubmarine Warfare (ASW) squadron. One aircraft flew a prearranged track dropping 1.8 lb of TROTYL, explosive charges, while the second aircraft remained in the area of a deployed calibrated passive sonobuoy, used as sonar receiver. Recorded broadband signals were analyzed with EFT techniques in selected 1/3 octave bands between 100 Ilz and 400 Hz. A code based on the parabolic equation method (PE) was used to model the down-slope propagation losses. A reasonable agreement was obtained when theoretical predictions were compared with experimental evidence. This agreement improves at low frequencies. Moreover, at high frequencies the greater the range the better fit is observed.En 1989 se ha realizado una experiencia sobre el Talud Continental Argentino para medir pérdidas por propagación acústica (TL) en un medio cuyas propiedades físicas dependen de la distancia, en una extensión de 50 km, usando dos aviones TRACKER de la Escuadrilla Naval Antisubmarina. Uno de los aviones arrojaba cargas explosivas de 1.8 libras de TROTYL, siguiendo un rumbo prefijado, mientras el otro permanecía en el área de sembrado de la sonoboya. actuando como sistema receptor. Las señales en banda ancha fueron analizadas con técnicas de FFT, en bandas de 1/3 de octava entre 100 Hz y 400 Hz. Para modelar las pérdidas por propagación se ha utilizado un código basado en el método de la ecuación parabólica. Se obtuvo un ajuste satisfactorio al comparar las predicciones teóricas con la evidencia experimental. Este ajuste es mejor a bajas frecuencias. A altas frecuencias, se observa un acuerdo mayor para grandes distancias.Material digitalizado en SEDICI gracias a la colaboración de la Facultad de Ciencias Astronómicas y Geofísicas (UNLP).Asociación Argentina de Geofísicos y Geodesta

MRSA screening by the Xpert MRSA PCR assay: pooling samples of the nose, throat, and groin increases the sensitivity of detection without increasing the laboratory costs.

The performance of the Xpert MRSA polymerase chain reaction (PCR) assay on pooled nose, groin, and throat swabs (three nylon flocked eSwabs into one tube) was compared to culture by analyzing 5,546 samples. The sensitivity [0.78, 95 % confidence interval (CI) 0.73-0.82] and specificity (0.99, 95 % CI 0.98-0.99) were similar to the results from published studies on separated nose or other specimens. Thus, the performance of the Xpert MRSA assay was not affected by pooling the three specimens into one assay, allowing a higher detection rate without increasing laboratory costs, as compared to nose samples alone

The EnerGEO Platform of Integrated Assessment (PIA): Environmental assessment of scenarios as a web service

With the International Energy Agency estimating that global energy demand will increase between 40 and 50 percent by 2030 (compared to 2003), scientists and policymakers are concerned about the sustainability of the current energy system and what environmental pressures might result from the development of future energy systems. EnerGEO is an ongoing FP7 Project (2009-2013) which assesses the current and future impact of energy use on the environment by linking environmental observation systems with the processes involved in exploiting energy resources. The idea of this European project is to determine how low carbon scenarios, and in particular scenarios with a high share of renewable electricity, affect emissions of air pollutants and greenhouse gases (GHG) and contribute to mitigation of negative energy system impacts on human health and ecosystems. A Platform of Integrated Assessment (PIA) has been elaborated to provide impact results for a selection of scenarios via a set of models (large-scale energy models, Life Cycle Assessment models, ...). This PIA is currently available through a web service. The concept of the PIA is detailed and to illustrate its interest, a set of results is given with the use of the simulation mode of the European version of GAINS for a selection of scenarios

MRSA screening by the Xpert MRSA PCR assay: pooling samples of the nose, throat, and groin increases the sensitivity of detection without increasing the laboratory costs

The performance of the Xpert MRSA polymerase chain reaction (PCR) assay on pooled nose, groin, and throat swabs (three nylon flocked eSwabs into one tube) was compared to culture by analyzing 5,546 samples. The sensitivity [0.78, 95% confidence interval (CI) 0.73-0.82] and specificity (0.99, 95% CI 0.98-0.99) were similar to the results from published studies on separated nose or other specimens. Thus, the performance of the Xpert MRSA assay was not affected by pooling the three specimens into one assay, allowing a higher detection rate without increasing laboratory costs, as compared to nose samples alon

Female labor supply and child care

We use household income tax data to estimate a structural model of female labor supply and utilization of paid child care outside the home. We find that child care costs have little impact on the participation decision of mothers of young children. However, they influence hours of work, as well as the decision to utilize paid child care. We use our results to simulate various policy reforms. Suppressing the APE (Parental Education Aid) would cause the participation rate in our sample to rise by 4 points and the proportion of mothers using outside paid care to rise by 2 points. Examining the effects on aggregate female labor supply of other policies that affect child care costs, we generally find that intensive effects caused by changes in working time are of the same order of magnitude as extensive effects due to changes in female participation.Child Care, female labor supply, fiscal policies