Presentación

La idea de que el ahorro desempeña un papel crucial en el proceso de desarrollo económico ha permeado a la literatura económica desde hace ya varias décadas. Se ha postulado que el ahorro determina la tasa de financiamiento de la acumulación de capital, lo que a su vez es determinante del crecimiento en el largo plazo. Si bien es cierto que la causalidad precisa entre ahorro, inversión y crecimiento está aún en debate, existe evidencia empírica de que hay una correlación positiva entre dichas variables. Por ejemplo, durante el periodo conocido como del Desarrollo Estabilizador en México (1959-1967), el crecimiento del producto interno bruto real, que fue de 6.5% anual en promedio, estuvo acompañado de un aumento en la propensión marginal a ahorrar de los individuos. De acuerdo con Ortiz Mena (1970), esta propensión aumentó de 0.13 entre 1951-1958 a 0.21 entre 1959-1967. Otro ejemplo es el observado en Chile durante la década de 1980, lapso en el cual coexistieron altas tasas de crecimiento de producto y del ahorro, como ha sido documentado en diversos estudios. Finalmente, tenemos el ejemplo de los países del sudeste asiático, los cuales mantuvieron durante muchos años un crecimiento sostenido acompañado de altas tasas de ahorro. En México este tema ha cobrado especial importancia en los últimos años, en particular a partir de la crisis del peso en diciembre de 1994. Las repercusiones negativas que tuvo la alta volatilidad de los flujos externos de capital obligó a las autoridades a subrayar la necesidad de aumentar el ahorro interno como elemento crucial para un crecimiento sostenido en el mediano y largo plazos. En el Plan Nacional de Desarrollo, el actual gobierno establece como uno de los puntos centrales de su proyecto económico recuperar los niveles pasados de ahorro interno para evitar que éste se constituya en una restricción para el crecimiento económico. Incluso se plantea un crecimiento en esta variable para el año 2000 de alrededor de 6 puntos porcentuales del producto. La posibilidad de lograr esta meta depende en gran medida del conocimiento que se tenga en la determinación del ahorro y de sus componentes, así como del entendimiento sobre su comportamiento, lo que permitirá diseñar las políticas adecuadas para su promoción. El contenido de este número de la revista Economía Mexicana, Nueva Época es el resultado de un esfuerzo conjunto realizado por el Centro de Investigación y Docencia Económicas (CIDE) y la Comisión Nacional del Sistema de Ahorro para el Retiro (Consar), por contribuir a una mayor comprensión y discusión sobre este importante tema. Los estudios aquí presentados forman parte del proyecto “Perspectivas del Ahorro en México” y fueron presentados y discutidos en un Seminario Internacional realizado en la ciudad de Puebla el 30 y 31 de octubre de 1998, al cual fueron invitados destacados especialistas nacionales e internacionales de los sectores académico, privado y público.

The Persistence and Functional Impact of English Language Difficulties Experienced by Children Learning English as an Additional Language and Monolingual Peers

Purpose This study explored whether a monolingual-normed English language battery could identify children with English as an additional language (EAL) who have persistent English language learning difficulties that affect functional academic attainment. Method Children with EAL (n = 43) and monolingual English-speaking children (n = 46) completed a comprehensive monolingual-normed English language battery in Year 1 (ages 5–6 years) and Year 3 (ages 7–8 years). Children with EAL and monolingual peers, who either met monolingual criteria for language impairment or typical development on the language battery in Year 1, were compared on language growth between Year 1 and Year 3 and on attainment in national curriculum assessments in Year 2 (ages 6–7 years). Results Children with EAL and monolingual peers who met monolingual criteria for language impairment in Year 1 continued to display comparably impaired overall language ability 2 years later in Year 3. Moreover, these groups displayed comparably low levels of academic attainment in Year 2, demonstrating comparable functional impact of their language difficulties. Conclusion Monolingual-normed language batteries in the majority language may have some practical value for identifying bilingual children who need support with language learning, regardless of the origin of their language difficulties

Vortices, Instantons and Branes

The purpose of this paper is to describe a relationship between the moduli space of vortices and the moduli space of instantons. We study charge k vortices in U(N) Yang-Mills-Higgs theories and show that the moduli space is isomorphic to a special Lagrangian submanifold of the moduli space of k instantons in non-commutative U(N) Yang-Mills theories. This submanifold is the fixed point set of a U(1) action on the instanton moduli space which rotates the instantons in a plane. To derive this relationship, we present a D-brane construction in which the dynamics of vortices is described by the Higgs branch of a U(k) gauge theory with 4 supercharges which is a truncation of the familiar ADHM gauge theory. We further describe a moduli space construction for semi-local vortices, lumps in the CP(N) and Grassmannian sigma-models, and vortices on the non-commutative plane. We argue that this relationship between vortices and instantons underlies many of the quantitative similarities shared by quantum field theories in two and four dimensions.Comment: 32 Pages, 4 Figure

Cross-national variations in reported discrimination among people treated for major depression worldwide : the ASPEN/INDIGO international study

No study has so far explored differences in discrimination reported by people with major depressive disorder (MDD) across countries and cultures. To (a) compare reported discrimination across different countries, and (b) explore the relative weight of individual and contextual factors in explaining levels of reported discrimination in people with MDD. Cross-sectional multisite international survey (34 countries worldwide) of 1082 people with MDD. Experienced and anticipated discrimination were assessed by the Discrimination and Stigma Scale (DISC). Countries were classified according to their rating on the Human Development Index (HDI). Multilevel negative binomial and Poisson models were used. People living in ‘very high HDI’ countries reported higher discrimination than those in ‘medium/low HDI’ countries. Variation in reported discrimination across countries was only partially explained by individual-level variables. The contribution of country-level variables was significant for anticipated discrimination only. Contextual factors play an important role in anticipated discrimination. Country-specific interventions should be implemented to prevent discrimination towards people with MDD

Escherichia coli and Staphylococcus aureus: bad news and good news from the European Antimicrobial Resistance Surveillance Network (EARS-Net), formerly EARSS), 2002 to 2009

Based on data collected by the European Antimicrobial Resistance Surveillance Network (EARS-Net) and the former EARSS, the present study describes the trends in antimicrobial susceptibility patterns and occurrence of invasive infections caused by Escherichia coli and Staphylococcus aureus in the period from 2002 to 2009. Antimicrobial susceptibility results from 198 laboratories in 22 European countries reporting continuously on these two microorganisms during the entire study period were included in the analysis. The number of bloodstream infections caused by E. coli increased remarkably by 71% during the study period, while bloodstream infections caused by S. aureus increased by 34%. At the same time, an alarming increase of antimicrobial resistance in E. coli was observed, whereas for S. aureus the proportion of meticillin resistant isolates decreased. The observed trend suggests an increasing burden of disease caused by E. coli. The reduction in the proportion of meticillin-resistant S. aureus and the lesser increase in S. aureus infections, compared with E. coli, may reflect the success of infection control measures at hospital level in several European countries.</p

National clinical practice guidelines for Allergen Immunotherapy:an international assessment applying AGREE-II

International audienc

Maternal Group B Streptococcal (GBS) Genital Tract Colonization at Term in Women who Have Asymptomatic GBS Bacteriuria

Objective: To determine the rate of positive group B streptococcus (GBS) cultures at 35–37 weeks gestation in women who have first trimester asymptomatic GBS bacteriuria. Methods: Pregnant women with asymptomatic first trimester GBS bacteriuria had genital cultures for GBS performed at 35–37 weeks gestational age. Serotyping was performed by the standard Lancefield capillary precipitin method. Results: Fifty-three women with positive urine cultures had genital cultures performed at 35–37 weeks. Sixteen of the 53 (30.2%; 95% confidence interval: 18.4–44.3%) third trimester vaginal cultures were positive for GBS. Five of eight (63%) of the women with typable urine serotypes had the same typable serotype in the third trimester genital culture. Conclusion: Genital tract cultures at 35–37 weeks for GBS correlate poorly with first trimester asymptomatic GBS bacteriuria. Recommendations for GBS prophylaxis in labor in women who have first trimester asymptomatic GBS bacteriuria should be investigated further and reconsidered