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Search Results: 1 - 10 of 876 matches for " CONSTANZA IVETTE; HARLOW "
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Condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México
Salud Pública de México , 1997, DOI: 10.1590/S0036-36341997000100002
Abstract: objective. to study the association between maternal working conditions and low birth-weight in mexico city. material and methods. interviews of 2 623 workers who gave birth in mexico city hospitals during 1992 were analyzed. information on the main biologic and social factors associated to low birth-weight was registered. occupational stress was determined with the instrument designed by karasek. logistic regression models to evaluate the relationship between working conditions and low birth-weight were used, controlling by confounding variables. results. low birth-weight was more frequent in workers with working periods of more than 50 h/week (or= 1.6; 95% ci= 1.17, 2.28) and with problems at work (or= 1.5; 95% ci= 1.0, 2.25). lack of tangible social support was identified as a risk factor for low birth-weight (or= 1.7; 95% ci= 1.20, 2.33). preventive working measures such as changes in tasks, shortening of working hours and leaves of absence due to illness did not show a beneficial effects on birth-weight, except for the maternity leave of absence. mothers with no right to this had a 2.2 higher probability of giving birth to low weight children (95% ci= 1.66, 2.93). conclusions. these results emphasize the importance of identifying the occupational risk factors during pregnancy.
Condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México
Salud Pública de México , 1997,
Abstract: Objetivo. Estudiar la asociación entre condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México. Material y métodos. Se encuestaron 2 623 trabajadoras que atendieron sus partos en tres grandes hospitales de la Ciudad de México en 1992. Se obtuvo información sobre los principales factores biológicos y sociales que se asocian al bajo peso al nacer; asimismo, se determinó el estrés ocupacional utilizando el instrumento desarrollado por Karasek. Se utilizaron modelos de regresión logística para evaluar la relación de las condiciones de trabajo con el bajo peso al nacer, controlando por variables confusoras. Resultados. El bajo peso al nacer fue más alto en trabajadoras con jornadas mayores a 50 horas semanales (RM= 1.6; IC= 1.17, 2.28) y con conflictos laborales (RM= 1.5; IC= 1.0, 2.25). La falta de apoyo social tangible fue identificado como un factor de riesgo de bajo peso al nacer (RM= 1.7; IC= 1.20, 2.33). Las medidas preventivas laborales como el cambio de tareas, disminución de la jornada y las salidas por enfermedad no mostraron un efecto benéfico en el peso al nacer, a excepción de la licencia de maternidad; las madres que no la tuvieron mostraron una probabilidad 2.2 veces mayor para bajo peso al nacer (IC= 1.66, 2.93). Conclusiones. Estos hallazgos resaltan la importancia de identificar los factores de riesgo ocupacional en el embarazo..
Public Spheres, Personal Papers, Pedagogical Practices: Ruth First’s Academic Postings to/ from Dar es Salaam and Maputo
B Harlow
Africa Development , 2010,
Abstract: This article proposes to consider, in particular, Ruth First’s work in her final years at the University of Dar es Salaam (Tanzania) and Universidade Eduardo Mondlane, Maputo, Mozambique (UEM), with reference to her own biographical trajectory and towards a reconsideration of contemporary and subsequent developments in the institutional history of post-independence education: public spheres (the university), personal papers (the archive), and pedagogical practices (the classroom).
Note on Pterergates in the Californian Harvester Ant
Harlow Shapley
Psyche , 1920, DOI: 10.1155/1920/73165
A Simple Bound on the Error of Perturbation Theory in Quantum Mechanics
Daniel Harlow
Physics , 2009,
Abstract: I provide a straightforward proof that a simple harmonic oscillator perturbed by an (almost) arbitrary positive interaction has a perturbative expansion for any finite-time Euclidian transition amplitude which obeys the following result: the difference of the sum of the first N terms of the series and the exact result is bounded in absolute value by the next term in the series. The proof makes no assumptions about either the strength of the interactions or the convergence of the perturbation series. I then argue that the result generalizes immediately to a much broader class of quantum mechanical systems, including bare perturbation theory in quantum field theory. The case of renormalized perturbation theory is more subtle and remains open, as does the generalization to energy levels and connected S-matrix elements.
Complementarity, not Firewalls
Daniel Harlow
Physics , 2012,
Abstract: In this note I argue that a version of complementarity is possible which evades the need for the "firewalls" recently proposed by Almheiri, Marolf, Polchinski, and Sully to burn up observers falling into black hole horizons. In particular I claim that it is consistent for an infalling observer to fall through an "old" black hole horizon without burning up, without this observer or any other seeing information loss or a violation of low energy effective field theory in an unexpected place. The reason that AMPS find the opposite conclusion is because they attempt to use low energy physics to translate between the quantum mechanics of different observers rather than to describe the experiments of only a single observer; I argue that this translation is polluted by short-distance physics related to stretched horizons.
Analytic Coleman-De Luccia Geometries
Xi Dong,Daniel Harlow
Physics , 2011, DOI: 10.1088/1475-7516/2011/11/044
Abstract: We present the necessary and sufficient conditions for a Euclidean scale factor to be a solution of the Coleman-De Luccia equations for some analytic potential $V(\phi)$, with a Lorentzian continuation describing the growth of a bubble of lower-energy vacuum surrounded by higher-energy vacuum. We then give a set of explicit examples that satisfy the conditions and thus are closed-form analytic examples of Coleman-De Luccia geometries.
Quantum Computation vs. Firewalls
Daniel Harlow,Patrick Hayden
Physics , 2013, DOI: 10.1007/JHEP06(2013)085
Abstract: In this paper we discuss quantum computational restrictions on the types of thought experiments recently used by Almheiri, Marolf, Polchinski, and Sully to argue against the smoothness of black hole horizons. We argue that the quantum computations required to do these experiments take a time which is exponential in the entropy of the black hole under study, and we show that for a wide variety of black holes this prevents the experiments from being done. We interpret our results as motivating a broader type of non-locality than is usually considered in the context of black hole thought experiments, and claim that once this type of non-locality is allowed there may be no need for firewalls. Our results do not threaten the unitarity of of black hole evaporation or the ability of advanced civilizations to test it.
El proceso creativo de la interfaz del sistema de gestión de la información
Revista Interamericana de Bibliotecología , 2010,
Abstract: often, users get to know the information management system (sgi) while using it. this can cause problems in information retrieval, especially if there is a discrepancy between the needs and expectations of the user and the representation of the task to be accomplished in the interface. this paper illustrates the design of the sgi interface from its inception. it takes intoaccount the user, the task (mental model), and the completion of the task (activity), with the support of cognitive ergonomics, the emotional design, usability, and an evaluation of the interface project. the techniques applied to this end were the analysis of the task and activity, systematic observation, paper prototyping, the target group, the questionnaire, the interview, and card management. the use of these techniques was based on the logic employed by the users and the logic of analysts and information professionals. this can facilitate the development and implementation of suggestions that would add value to the understanding and the analysis of the issues involved in the design of the sgi interface and it can also encourage increased user satisfaction.
Observations of a Labidus Coecus (Latreille) Underground Raid in the Central Highlands ofCosta Rica
Ivette Perfecto
Psyche , 1992, DOI: 10.1155/1992/47525
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