Communication: Reduced density matrices in molecular systems: Grand-canonical electron states

Grand-canonical like descriptions of many electron atomic and molecular open systems which are characterized by a non-integer number of electrons are presented. Their associated reduced density matrices (RDMs) are obtained by introducing the contracting mapping for this type of distributions. It is shown that there is loss of information when connecting RDMs of different order by partial contractions. The energy convexity property of these systems simplifies the description. Consequently, this formulation opens the possibility to a new look for chemical descriptors such as chemical potential and reactivity among others. Examples are presented to discuss the theoretical aspects of this work. © 2013 AIP Publishing LLC.Fil:Bochicchio, R.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Rial, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Opinión de los empleadores respecto al desempeño de los egresados del Plan Único de Especialización en Enfermería de la ENEO

ResumenIntroducciónLas Instituciones de Educación Superior requieren evaluar de manera permanente la pertinencia de su oferta educativa en función de las demandas del mercado de trabajo, a fin de garantizar las mejores condiciones para la inserción, desarrollo y desempeño profesional de sus egresados.ObjetivoIdentificar la opinión de los empleadores sobre el desempeño de los egresados del Plan Único de Especialización en Enfermería (PUEE) de la ENEO-UNAM.MétodosSe entrevistaron a empleadores de 11 instituciones de salud (9 públicas, una privada y una asociación civil), ubicadas en su mayoría en el D.F. y del tercer nivel de atención. Las variables estudiadas fueron las competencias generales, conocimientos específicos, atributos, actitudes y valores, para cada una se elaboraron diferentes ítems conforme a las características señaladas en el perfil del egresado del PUEE, el instrumento quedó integrado por 39 ítems en total, con una escala de respuestas que califica el desempeño de 1 al 5 equivalente a muy deficiente, deficiente, aceptable, muy aceptable y excelente, respectivamente.ResultadosLos empleadores consideran que los egresados tienen un nivel muy aceptable de conocimientos propios de la especialidad, de los cuidados especializados, del Proceso de Atención de Enfermería (PAE) y del lenguaje especializado; hubo diferencias en las calificaciones según el tamaño de las instituciones, las foráneas otorgaron mejores que los institutos nacionales de salud. DiscusiónEl nivel de desempeño es acorde con calidad en la atención, y debiera permanecer como distintivo del actuar del profesional de enfermería. Se requiere reforzar la capacidad de toma de decisiones, de autocrítica, entre otras y, analizar casos particulares de instituciones que otorgaron calificaciones menores.AbstractIntroductionHigh Level Education Institutions need to assess their education offer pertinence in terms of the labor market demands in order to guarantee the best conditions for the professional development of their graduates.ObjectiveIdentify the opinion of employers on the performance of the ENEO-UNAM Nursing Specialization Unique Plan (PUEE) graduates.MethodsEmployers from eleven 3rd level attention health institutions (9 public, one private, and one civil association) and located mainly in the Federal District, were interviewed. Studied variables included general competencies, specific knowledge, attributes, attitudes and values. The final instrument had 39 items to be graded as 1=very deficient, 2=deficient, 3=acceptable, 4=very acceptable, or 5=outstanding.ResultsEmployers considered that the graduates have a very acceptable level of specialty knowledge, specialized care, nursing attention process (NAP), and specialized language. There were differences in the grades depending on the institution size; the distant ones giving better scores than the national institutes of health.DiscussionThe performance level is proportional to the attention quality, and should stay as a nursing professional distinctive. It is necessary to strengthen the decision taking and self-assessment capacity, among other, and analyze the particular cases of the institutions which gave lower scores

Is the Sgr dSph a dark matter dominated system?

We study the evolution of possible progenitors of Sgr dSph}using several numerical N-body simulations of different dwarf spheroidal galaxies both with and without dark matter, as they orbit the Milky Way. The barionic and dark components of the dwarfs were made obeying a Plummer and NFW potentials of one million particles respectively. The Milky Way was modeled like a tree-component rigid potential and the simulations were performed using a modified Gadget-2 code. We found that none of the simulated galaxies without dark matter reproduced the physical properties observed in Sgr dSph, suggesting that, at the beginning of its evolution, Sgr dSph might have been immersed in a dark matter halo. The simulations of progenitors immersed in dark matter halos suggest that Sgr dSph at its beginning might have been an extended system, i.e. its Plummer radius could have had a value approximated to 1.2 kpc or higher; furthermore, this galaxy could have been immersed in a dark halo with a mass higher than 10^8 solar masses. These results are important for the construction of a model of the formation of Sgr dSph.Comment: 13 pages, 6 figures, New Astronomy - accepte

Branching Fractions for D0 -> K+K- and D0 -> pi+pi-, and a Search for CP Violation in D0 Decays

Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we have measured ratios of branching fractions for the two-body singly-Cabibbo-suppressed charged decays of the D0: (D0 -> KK)/(D0 -> Kpi) = 0.109 +- 0.003 +- 0.003, (D0 -> pipi)/(D0 -> Kpi) = 0.040 +- 0.002 +- 0.003, and (D0 -> KK)/(D0 -> pipi) = 2.75 +- 0.15 +- 0.16. We have looked for differences in the decay rates of D0 and D0bar to the CP eigenstates K+K- and pi+pi-, and have measured the CP asymmetry parameters A_CP(K+K-) = -0.010 +- 0.049 +- 0.012 and A_CP(pi+pi-) = -0.049 +- 0.078 +- 0.030, both consistent with zero.Comment: 10 Postscript pages, including 2 figures. Submitted to Phys. Lett.

Asymmetries between the production of D+ and D- mesons from 500 GeV/c pi- nucleon interactions as a function of xF and pt**2

We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used

Search for Rare and Forbidden Dilepton Decays of the D+, Ds, and D0 Charmed Mesons

We report the results of a search for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examine the pi,l,l and K,l,l decay modes of D+ and Ds and the l+l- decay modes of D0. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 24 decay modes examined. Eight of these modes have no previously reported limits, and fourteen are reported with significant improvements over previously published results.Comment: 12 pages, 3 figures, LaTeX, elsart.cls, epsf.sty, amsmath.sty Submitted to Physics Letters

Search for CP Violation in Charged D Meson Decays

We report results of a search for CP violation in the singly Cabibbo-suppressed decays D+ -> K- K+ pi+, phi pi+, K*(892)0 K+, and pi- pi+ pi+ based on data from the charm hadroproduction experiment E791 at Fermilab. We search for a difference in the D+ and D- decay rates for each of the final states. No evidence for a difference is seen. The decay rate asymmetry parameters A(CP), defined as the difference in the D+ and D- decay rates divided by the sum of the decay rates, are measured to be: A(CP)(K K pi) = -0.014 +/- 0.029, A(CP)(phi pi) = -0.028 +/- 0.036, A(CP)(K*(892) K) = -0.010 +/- 0.050, and A(CP)(pi pi pi) = -0.017 +/- 0.042.Comment: 13 pages, 5 figures, 1 table; Elsevier LaTe

Measurement of the form-factor ratios for D+ --> K* l nu

The form factor ratios rv=V(0)/A1(0), r2=A2(0)/A1(0) and r3=A3(0)/A1(0) in the decay D+ --> K* l nu, K* -->K-pi+ have been measured using data from charm hadroproduction experiment E791 at Fermilab. From 3034 (595) signal (background) events in the muon channel, we obtain rv=1.84+-0.11+-0.09, r2=0.75+-0.08+-0.09 and, as a first measurement of r3, we find 0.04+-0.33 +-0.29. The values of the form factor ratios rv and r2 measured for the muon channel are combined with the values of rv and r2 that we have measured in the electron channel. The combined E791 results for the muon and electron channels are rv=1.87+-0.08+-0.07 and r2=0.73+-0.06+-0.08.Comment: 9 pages + 3 figures ; submitted to PL

Differential cross sections, charge production asymmetry, and spin-density matrix elements for D*(2010) produced in 500 GeV/c pi^- nucleon interactions

We report differential cross sections for the production of D*(2010) produced in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also report the D* +/- charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are \eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles, respectively.Comment: LaTeX2e (elsart.cls). 13 pages, 6 figures (eps files). Submitted to Physics Letters

Mass Splitting and Production of Σc0\Sigma_c^0 and Σc++\Sigma_c^{++} Measured in 500GeV500 {GeV} π−−\pi^- -N Interactions

From a sample of $2722 \pm 78$ $\Lambda_c^+$ decaying to the $pK^-\pi^+$ final state, we have observed, in the hadroproduction experiment E791 at Fermilab, $143 \pm 20$ $\Sigma_c^0$ and $122 \pm 18$ $\Sigma_c^{++}$ through their decays to $\Lambda_c^+ \pi^{\pm}$. The mass difference $M(\Sigma_c^0) - M(\Lambda_c^+$) is measured to be $(167.38\pm 0.29\pm 0.15) {MeV}$; for $M(\Sigma_c^{++}) - M(\Lambda_c^+)$, we find $(167.76\pm 0.29\pm0.15) {MeV}$. The rate of $\Lambda_c^+$ production from decays of the $\Sigma_c$ triplet is (22\pm 2\pm 3) {%} of the total $\Lambda_c^+$ production assuming equal rate of production from all three, as measured for $\Sigma_c^0$ and $\Sigma_c^{++}$. We do not observe a statistically significant $\Sigma_c$ baryon-antibaryon production asymmetry. The $x_F$ and $p_t^2$ spectra of $\Lambda_c^+$ from $\Sigma_c$ decays are observed to be similar to those for all $\Lambda_c^+$'s produced.Comment: 15 pages, uuencoded postscript 3 figures uuencoded, tar-compressed fil