257 research outputs found
Nudging Youth to Develop Savings Habits: Experimental Evidence Using SMS Messages
In this working paper, we report on a field experiment articulating financial information via cellphone text messages and financial decisions among low-income youth in Colombia. For twelve months, youth accountholders are randomly assigned to receive either: (a) monthly financial education messages, (b) monthly savings reminders, (c) semimonthly reminders, or (d) control. After 12 months, account balances in monthly and semimonthly reminders groups increase by 28% and 43%, respectively, relative to controls. Financial education messages do not increase balances. Over two thirds of balance increases in reminder groups are net savings. Savings effects of reminders last eight months after youth stop receiving messages
Top quark physics at colliders
Presented by E.W.N. Glover at the final meeting of the European Network “Physics
at Colliders”, Montpellier, France, september 26–27, 2004.We review some recent developments in top quark production and decay at current and future colliders.This work has been supported by the European Community’s Human Potential Programme under contract HPRN-CT-2000-00149
Heavy neutrino signals at large hadron colliders
We study the LHC discovery potential for heavy Majorana neutrino singlets in
the process pp -> W+ -> l+ N -> l+ l+ jj (l=e,mu) plus its charge conjugate.
With a fast detector simulation we show that backgrounds involving two
like-sign charged leptons are not negligible and, moreover, they cannot be
eliminated with simple sequential kinematical cuts. Using a likelihood analysis
it is shown that, for heavy neutrinos coupling only to the muon, LHC has 5
sigma sensitivity for masses up to 200 GeV in the final state mu+- mu+- jj.
This reduction in sensitivity, compared to previous parton-level estimates, is
driven by the ~ 10^2-10^3 times larger background. Limits are also provided for
e+- e+- jj and e+- mu+- jj final states, as well as for Tevatron. For heavy
Dirac neutrinos the prospects are worse because backgrounds involving two
opposite charge leptons are much larger. For this case, we study the
observability of the lepton flavour violating signal e+- mu-+ jj. As a
by-product of our analysis, heavy neutrino production has been implemented
within the ALPGEN framework.Comment: Latex 36 pages, 49 PS figures. Major extension incorporating analysis
for e+- e+-, e+- mu+- and e+- mu-+ final states. Final version to appear in
JHE
l W nu production at CLIC: a window to TeV scale non-decoupled neutrinos
We discuss single heavy neutrino production e+ e- -> N nu -> l W nu, l = e,
mu, tau, at a future high energy collider like CLIC, with a centre of mass
energy of 3 TeV. This process could allow to detect heavy neutrinos with masses
of 1-2 TeV if their coupling to the electron V_eN is in the range 0.004-0.01.
We study the dependence of the limits on the heavy neutrino mass and emphasise
the crucial role of lepton flavour in the discovery of a positive signal at
CLIC energy. We present strategies to determine heavy neutrino properties once
they are discovered, namely their Dirac or Majorana character and the size and
chirality of their charged current couplings. Conversely, if no signal is
found, the bound V_eN < 0.002-0.006 would be set for masses of 1-2 TeV,
improving the present limit up to a factor of 30. We also extend previous work
examining in detail the flavour and mass dependence of the corresponding limits
at ILC, as well as the determination of heavy neutrino properties if they are
discovered at this collider.Comment: LaTeX 32 pages. Added comments and references. Matches version to
appear in JHE
Categorías de riesgo coronario y logro de la meta de LDL colesterol según edad y género en la población adulta de Trujillo, La Libertad, Perú 2007
Introducción: el Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults estableció el LDL colesterol como blanco primario de tratamiento.
Objetivo: determinar la frecuencia de las categorías de riesgo coronario y logro de las metas de LDL en adultos de Trujillo según edad y género.
Material y método: a 123 mujeres y 123 varones, en grupos iguales de 20 a 39 , 40 a 59 y 60 a 79 años, seleccionados al azar, se les hizo evaluación clínica, de glicemia y perfil lipídico.
Resultados: la frecuencia de riesgo coronario fueron: bajo 73,98 %, moderado 5,28 %, moderado alto 11,79 % y alto 8,94 %. Los riesgos moderado alto y alto fueron más frecuentes a los 60 a 79 años (p < 0,0004) 26,83 % y 20,8 % respectivamente y en los varones (p=0.045) . El logro de la meta de LDL fue 67,89 %, , sin diferencia de género y disminuyó a los 60 a 79 años, 53,76 %; en riesgo bajo 76,92 %, moderado 61,54 % ,moderado alto 51,72 % y alto 18,18% ; en los diabéticos 12,5 %. La edad, la frecuencia de hipertensión, de diabetes, y las concentraciones de colesterol y LDL fueron significativamente mayores en aquellos que no cumplieron la meta de LDL . El logro de la meta de no HDL colesterol fue 43,8 %
Conclusiones: la frecuencia de las categorías de riesgo coronario más altas aumenta con la edad y en los varones. El logro de la meta de LDL colesterol fue de 67,89 %, similar en ambos géneros, y disminuyó con la edad
Quasinormal Modes of Extremal BTZ Black Hole
Motivated by several pieces of evidence, in order to show that extreme black
holes cannot be obtained as limits of non-extremal black holes, in this article
we calculate explicitly quasinormal modes for Ba\~{n}ados, Teitelboim and
Zanelli (BTZ) extremal black hole and we showed that the imaginary part of the
frequency is zero. We obtain exact result for the scalar an fermionic
perturbations. We also showed that the frequency is bounded from below for the
existence of the normal modes (non-dissipative modes).Comment: 6 pp. Accepted Classical and Quantum Gravity. Typos corrected and
some references was added. Final Versio
Light Higgs boson discovery from fermion mixing
We evaluate the LHC discovery potential for a light Higgs boson in t tbar H
(-> l nu b bbar b bbar jj) production, within the Standard Model and if a new
Q=2/3 quark singlet T with a moderate mass exists. In the latter case, T pair
production with decays T Tbar -> W+ b H tbar / H t W- bbar -> W+ b W- bbar H
provides an important additional source of Higgs bosons giving the same
experimental signature, and other decay modes T Tbar -> H t H tbar -> W+ b W-
bbar H H, T Tbar -> Z t H tbar / H t Z tbar -> W+ b W- bbar H Z further enhance
this signal. Both analyses are carried out with particle-level simulations of
signals and backgrounds, including t tbar plus n=0...5 jets which constitute
the main background by far. Our estimate for SM Higgs discovery in t tbar H
production, 0.4 sigma significance for M_H = 115 GeV and an integrated
luminosity of 30 fb^-1, is similar to the most recent ones by CMS which also
include the full t tbar nj background. We show that, if a quark singlet with a
mass m_T = 500 GeV exists, the luminosity required for Higgs discovery in this
final state is reduced by more than two orders of magnitude, and 5 sigma
significance can be achieved already with 8 fb^-1. This new Higgs signal will
not be seen unless we look for it: with this aim, a new specific final state
reconstruction method is presented. Finally, we consider the sensitivity to
search for Q=2/3 singlets. The combination of these three decay modes allows to
discover a 500 GeV quark with 7 fb^-1 of luminosity.Comment: LaTeX, 37 pages, 57 PS figures. Many improvements in the analysis.
Final version to appear in JHE
Colombian consensus on the diagnosis, treatment, and prevention of candida Spp. disease in children and adults
La Candidiasis Invasora (CI) y la candidemia, como su manifestación más frecuente, se ha convertido en la principal causa de micosis oportunista a nivel hospitalario. Este manuscrito realizado por miembros de la Asociación Colombiana de Infectología (ACIN), tuvo como objetivo proporcionar un conjunto de recomendaciones para manejo, seguimiento y prevención de la CI/candidemia y de la infección candidiásica de mucosas, en población adulta, pediátrica y neonatal, en un
entorno hospitalario, incluyendo las unidades hemato-oncológicas y unidades de cuidado crítico. Todos los datos obtenidos mediante una búsqueda exhaustiva,
fueron revisados y analizados de manera amplia por todos los miembros del grupo, y las recomendaciones emitidas se elaboraron luego de la evaluación de la literatura científica disponible, y el consenso de todos los especialistas involucrados, reconociendo el problema de la emergencia de las infecciones por Candida Spp.
y brindando una correcta orientación a los profesionales de la salud sobre el manejo de pacientes con enfermedad candidiásica, de una forma racional y práctica,
enfatizando en la evaluación del paciente, estrategias de diagnóstico, profilaxis, tratamiento empírico, tratamiento dirigido y terapia preventiva.Invasive Candidiasis (IC) and candidemia (as its most frequent manifestation) have become the main cause of opportunistic mycosis at hospital settings. This
study, made by members of the Colombian Association of Infectious Diseases (ACIN), was aimed at providing a set of recommendations for the management,
follow-up and prevention of IC / candidemia and mucous membrane candida infection in adult, pediatric and neonatal patients in a hospital setting, including the
hemato-oncological and critical care units. All the data obtained through an exhaustive search were reviewed and analyzed in a comprehensive manner by all the
members of the group, and the recommendations issued are being made after a careful review of the scientific literature available and the consensus of all specialists involved; the emergence of Candida Spp. problem is highlighted and a correct orientation to health professionals regarding the management of patients with
candidiasis is provided in a rational and practical way, emphasizing patient evaluation, diagnostic strategies, prophylaxis, empirical treatment, directed treatment
and preventative therap
Carbapenemase-Producing Extraintestinal Pathogenic Escherichia coli From Argentina: Clonal Diversity and Predominance of Hyperepidemic Clones CC10 and CC131
Extraintestinal pathogenic Escherichia coli (ExPEC) causes infections outside the intestine. Particular ExPEC clones, such as clonal complex (CC)/sequence type (ST)131, have been known to sequentially accumulate antimicrobial resistance that starts with chromosomal mutations against fluoroquinolones, followed with the acquisition of blaCTX–M–15 and, more recently, carbapenemases. Here we aimed to investigate the distribution of global epidemic clones of carbapenemase-producing ExPEC from Argentina in representative clinical isolates recovered between July 2008 and March 2017. Carbapenemase-producing ExPEC (n = 160) were referred to the Argentinean reference laboratory. Of these, 71 were selected for genome sequencing. Phenotypic and microbiological studies confirmed the presence of carbapenemases confirmed as KPC-2 (n = 52), NDM-1 (n = 16), IMP-8 (n = 2), and VIM-1 (n = 1) producers. The isolates had been recovered mainly from urine, blood, and abdominal fluids among others, and some were from screening samples. After analyzing the virulence gene content, 76% of the isolates were considered ExPEC, although non-ExPEC isolates were also obtained from extraintestinal sites. Pan-genome phylogeny and clonal analysis showed great clonal diversity, although the first phylogroup in abundance was phylogroup A, harboring CC10 isolates, followed by phylogroup B2 with CC/ST131, mostly H30Rx, the subclone co-producing CTX-M-15. Phylogroups D, B1, C, F, and E were also detected with fewer strains. CC10 and CC/ST131 were found throughout the country. In addition, CC10 nucleated most metalloenzymes, such as NDM-1. Other relevant international clones were identified, such as CC/ST38, CC155, CC14/ST1193, and CC23. Two isolates co-produced KPC-2 and OXA-163 or OXA-439, a point mutation variant of OXA-163, and three isolates co-produced MCR-1 among other resistance genes. To conclude, in this work, we described the molecular epidemiology of carbapenemase-producing ExPEC in Argentina. Further studies are necessary to determine the plasmid families disseminating carbapenemases in ExPEC in this region.Fil: Sanz, María Belén. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: de Belder, Denise Gisele. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de Mendieta, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Faccone, Diego Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Poklepovich, Tomás. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Lucero, Celeste. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Rapoport, Melina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Campos, Josefina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Tuduri, Ezequiel. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Saavedra, Mathew O.. Houston Methodist Hospital; Estados UnidosFil: Van der Ploeg, Claudia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; ArgentinaFil: Rogé, Ariel Diego. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; ArgentinaFil: Pasteran, Fernando. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Corso, Alejandra. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Rosato, Adriana E.. University of California; Estados UnidosFil: Gómez, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; Argentin
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