Are Conditional Cash Transfers Effective in Urban Areas? Evidence from Mexico

Conditional cash transfer (CCT) programs have spread worldwide as a new form of social assistance for the poor. Previous evaluations of CCT programs focus mainly on rural settings, and little is known about their effects in urban areas. This paper studies the short-term (one and two-year) effects of the Mexican Oportunidades CCT program on urban children/youth. The program provides financial incentives for children/youth to attend school and for family members to visit health clinics. To participate, families had to sign up for the program and be deemed eligible. Difference-in-difference propensity score matching estimates indicate that the program is successful in increasing school enrollment, schooling attainment and time devoted to homework and in decreasing working rates of boys.conditional cash transfer programs, matching estimators, program evaluation

Multiple scattering effects in quasi free scattering from halo nuclei: a test to Distorted Wave Impulse Approximation

Full Faddeev-type calculations are performed for $^{11}$Be breakup on proton target at 38.4, 100, and 200 MeV/u incident energies. The convergence of the multiple scattering expansion is investigated. The results are compared with those of other frameworks like Distorted Wave Impulse Approximation that are based on an incomplete and truncated multiple scattering expansion.Comment: 7 pages, 16 figures, to be published in Phys. Rev.

Discrete generalized half-normal distribution and its applications in quantile regression

A new discrete two-parameter distribution is introduced by discretizing a generalized half-normal distribution. The model is useful for fitting overdispersed as well as underdispersed data. The failure function can be decreasing, bathtub shaped or increasing. A reparameterization of the distribution is introduced for use in a regression model based on the median. The behaviour of the maximum likelihood estimates is studied numerically, showing good performance in finite samples. Three real data set applications reveal that the new model can provide a better explanation than some other competitors

Changes in the proteome of pea (Pisum sativum L.) seeds germinating under optimal and osmotic stress conditions and subjected to post-stress recovery

Plants growing under natural conditions are exposed to a variety of stresses, which can lead to undesirable changes in the physiological processes and yielding. These changes can be regulated at different levels, resulting in the synthesis of specific proteins which participate in the plant's response to stress. The purpose of this study was to determine changes in the accumulation of proteins in germinating pea (Pisum sativum L.) seeds under optimal and osmotic (short- and long-term) stress conditions as well as recovery following a short-term stress. For identification of the proteins, two-dimensional electrophoresis and mass spectrometry (MALDI-TOF) were employed. Germination in optimal conditions increased the accumulation of several proteins involved in glycolysis, Krebs cycle, synthesis of fatty acids, cell growth, cellular transport and detoxification. Osmotic stress, in turn, depressed the accumulation of proteins involved in glycolysis, synthesis of fatty acids, detoxication, methionine conversions, cellular transport, translation, growth control and of cytoskeletal proteins, but raised the accumulation of enzymes of the tricarboxylic acid cycle as well as proteins participating in signal transduction and protection (chaperones). One protein, 6a-hydroxymaackian-3-O-methyltransferase, which is involved in the synthesis of pisatin, was present only under osmotic stress conditions and recovery. Pisatin is synthesized mainly in response to microbiological infections and under stress conditions, indicating its key role in the acquisition of stress tolerance by plants

Application of dosimetry measurements to analyze the neutron activation of a stainless steel sample in a training nuclear reactor

All materials present in the core of a nuclear reactor are activated by neutron irradiation. The activity so generated produces a dose around the material. This dose is a potential risk for workers in the surrounding area when materials are withdrawn from the reactor. Therefore, it is necessary to assess the activity generated and the dose produced. In previous works, neutron activation of control rods and doses around the storage pool where they are placed have been calculated for a Boiling Water Reactor using the MCNP5 code based on the Monte Carlo method. Most of the activation is produced indeed in stainless steel components of the nuclear reactor core not only control rods. In this work, a stainless steel sample is irradiated in the Training Reactor AKR-2 of the Technical University Dresden. Dose measurements around the sample have been performed for different times after the irradiation. Experimental dosimetric values are compared with results of Monte Carlo simulation of the irradiation. Comparison shows a good agreement. Hence, the activation Monte Carlo model can be considered as validated.Ródenas Diago, J.; Gallardo Bermell, S.; Weirich, F.; Hansen, W. (2014). Application of dosimetry measurements to analyze the neutron activation of a stainless steel sample in a training nuclear reactor. Radiation Physics and Chemistry. 104:368-371. doi:10.1016/j.radphyschem.2014.05.013S36837110

Scale Mixture of Rayleigh Distribution

In this paper, the scale mixture of Rayleigh (SMR) distribution is introduced. It is proven that this new model, initially defined as the quotient of two independent random variables, can be expressed as a scale mixture of a Rayleigh and a particular Generalized Gamma distribution. Closed expressions are obtained for its pdf, cdf, moments, asymmetry and kurtosis coefficients. Its lifetime analysis, properties and Rényi entropy are studied. Inference based on moments and maximum likelihood (ML) is proposed. An Expectation-Maximization (EM) algorithm is implemented to estimate the parameters via ML. This algorithm is also used in a simulation study, which illustrates the good performance of our proposal. Two real datasets are considered in which it is shown that the SMR model provides a good fit and it is more flexible, especially as for kurtosis, than other competitor models, such as the slashed Rayleigh distribution

Towards a definition of quantum integrability

We briefly review the most relevant aspects of complete integrability for classical systems and identify those aspects which should be present in a definition of quantum integrability. We show that a naive extension of classical concepts to the quantum framework would not work because all infinite dimensional Hilbert spaces are unitarily isomorphic and, as a consequence, it would not be easy to define degrees of freedom. We argue that a geometrical formulation of quantum mechanics might provide a way out.Comment: 37 pages, AmsLatex, 1 figur

Different Methods for the Two-Nucleon T-Matrix in the Operator Form

We compare three methods to calculate the nucleon-nucleon t-matrix based on the three-dimensional formulation of J. Golak et al., Phys. Rev. C 81, 034006, (2010). In the first place we solve a system of complex linear inhomogeneous equations directly for the t-matrix. Our second method is based on iterations and a variant of the Lanczos algorithm. In the third case we obtain the t-matrix in two steps, solving a system of real linear equations for the k-matrix expansion coefficients and then solving an on-shell equation, which connects the scalar coefficients of the k- and t-matrices. A very good agreement among the three methods is demonstrated for selected nucleon-nucleon scattering observables using a chiral next-to-next-to-leading-order neutron-proton potential. We also apply our three-dimensional framework to the demanding problem of proton-proton scattering, using a corresponding version of the nucleon-nucleon potential and supplementing it with the (screened) Coulomb force, taken also in the three-dimensional form. We show converged results for two different screening functions and find a very good agreement with other methods dealing with proton-proton scattering.Comment: 18 pages, 10 figures (54 eps files

A Note on the Log-Alpha-Skew-Normal Model with Geochemical Applications.

In this paper we introduce an extension of the log-normal distribution, based on the alpha-skew-normal distribution introduced by Elal-Olivero [10]. Basic properties, moments, moment estimators, maximum likelihood estimators and a simulation study are discussed. We apply the approach developed in this paper to data sets related to neodymium and nickel concentrations in soil samples. Model fit indicates good performance of the proposed model when compared with less flexible models