A zero-thickness mortar/ interface formulation with application to fracture mechanics

A zero-thickness mortar/interface element formulation is briefly described and demonstrated. This element may be considered as an extension of traditional zero-thickness interface element, in order to represent material interfaces located in between subdomains with non-matching FE meshes. In the context of small strain analysis, these elements may be equipped with the same type of constitutive laws as traditional interface elements. Therefore, if friction or fracture-mechanics-based laws are adopted, mortar/interface elements may be used to represent frictional sliding or cracking following the lines (surfaces) along which they have been pre-inserted. Two basic verification examples of this type are presented, showing that the model can correctly represent uniform states of stress and deformation when connecting unmatched mesh subdomains

A zero-thickness mortar / Interface formulation with application to fracture mechanics

A zero-thickness mortar/interface element formulation is briefly described and demonstrated. This element may be considered as an extension of traditional zero-thickness interface element, in order to represent material interfaces located in between subdomains with non-matching FE meshes. In the context of small strain analysis, these elements may be equipped with the same type of constitutive laws as traditional interface elements. Therefore, if friction or fracture-mechanics-based laws are adopted, mortar/interface elements may be used to represent frictional sliding or cracking following the lines (surfaces) along which they have been pre-inserted. Two basic verification examples of this type are presented, showing that the model can correctly represent uniform states of stress and deformation when connecting unmatched mesh subdomains.Postprint (published version

Estimation of quantiles and the interquartile range in complex surveys

An estimator of the population distribution function that can be used with the complex sampling designs found in survey sampling is given. This estimator is used to define a quantile estimator and an estimator of the interquartile range that are based on the survey design. A design-consistent superpopulation model is assumed, and large sample properties of estimators constructed from single-stage stratified cluster samples are presented. Extensions to other complex designs are discussed. Based on these results, large-sample procedures for constructing confidence sets for quantiles and the interquartile range are given. Design-based variance estimators for both the quantile estimator and the interquartile range are derived form these procedures;The proposed estimation procedures have been incorporated into PC CARP, a computer program which analyzes data from one-stage or two-stage stratified cluster samples. Computational procedures used to esimate the distribution function, quantiles, the interquartile range, and other associated statistics are briefly described;Three Monte Carlo simulation studies were performed to evaluate the performance of this implementation of the proposed estimation procedures. For the populations and sample sizes included in the studies, sample quantiles of order 0.25, 0.50, and 0.75 displayed near zero bias. Comparison of observed variances of the quantile estimators to the average of variance estimators across simulated samples showed that the proposed variance estimator is acceptable. In all cases, the obtained coverage probabilities for confidence intervals were near the nominal level of 95 percent

Soil salinization in marshes : study case: Samborombón Bay wetland, Argentina

En el sector sur de la Bahía de Samborombón (Buenos Aires, Argentina) se desarrolla una extensa marisma que forma un humedal intermareal. En ella se realizaron distintas obras de ingeniería con el fin de evitar el ingreso del flujo mareal y lograr una mayor extensión del área de pastoreo. El objetivo del trabajo es evaluar si la regulación de los flujos mareales ocasiona una modificación en el contenido de cloruros en los sedimentos superficiales, afectando la salinidad de los suelos del humedal. Se realizaron interpretaciones de imágenes satelitales, relevamientos de campo, muestreos de sedimentos y mediciones de niveles y conductividad eléctrica del agua superficial y subterránea. Los resultados obtenidos permitieron reconocer cómo las obras de ingeniería (terraplenes de contención y caminos internos) alteran el comportamiento hidrológico natural y en consecuencia el contenido de cloruros en el sedimento. Problemas de salinización de suelos se reconocen en sectores donde el agua mareal se acumula y luego se evapora formando precipitados de halita. Las futuras obras deberán planificarse de forma tal de minimizar la alteración de los flujos de agua con el fin de lograr un manejo sustentable de los recursos naturales en el humedal.The southern sector of the Samborombón Bay (Buenos Aires, Argentina) is an extensive marsh that is associated with an intertidal wetland environment. Different engineering works were built to avoid tidal inflow and to increase the livestock grazing areas. The objective of this work is to assess if the regulation of tidal inflow causes a chloride content change in the surface sediments, affecting the soil salinity of the wetland. Interpretation of satellite images, field surveys, sampling of sediments, and electrical conductivity and levels measurements of surface and groundwater were carried out. The results allowed us to recognize how engineering works (embankments and internal roads) alter the natural hydrological behavior, and, therefore the chloride content in the sediment. Soil salinization problems are recognized in areas where the tidal water accumulates and then evaporates forming halite precipitates. Future engineering works should be planned so as to minimize the alteration of the water flow in order to achieve a sustainable management of natural resources in the wetland.Fil: Carol, Eleonora S.. Universidad Nacional de La PlataFil: Kruse, Eduardo E.. Universidad Nacional de La PlataFil: Cellone, Francisco A.. Universidad Nacional de La Plat

Effect of Butoconazole Nitrate 2% Vaginal Cream and Miconazole Nitrate 2% Vaginal Cream Treatments in Patients with Vulvovaginal Candidiasis

In a multicenter, randomized, invesgtigator-blind, parallel study, 398 patients were dispensed topical butoconazole nitrate 2% cream for 3 days (n = 199) or miconazole nitrate 2% cream for 7 days (n = 199) for vaginal use. Efficacy analyses included 254 patients with culture-confirmed Candida (119 butoconazole and 135 miconazole users). Of the 398 patients issued study medication, 9 were lost to follow-up. Therefore, safety analyses included 389 patients (197 butoconazole and 192 miconazole users). Evaluations upon admission and approximately 8 and 30 days post-treatment included Candida cultures, potassium hydroxide (KOH) wet mounts, and vulvovaginal examinations, with rating of vulvovaginal signs and symptoms using a 4-point scale. Rates of clinical cure (based on sign/symptom scores), microbiologic cure (based on cultures and wet mounts), and therapeutic cure (both clinical and microbiologic cures) were assessed and were to be similar between the regimens. Therapeutic cure rates were 57.8% and 61.4% for butoconazole and miconazole, respectively. Three-day butoconazole treatment was as safe and effective as 7-day miconazole therapy in treating vulvovaginal candidiasis

Clinical manifestations of geriatric depression in a memory clinic: Toward a proposed subtyping of geriatric depression

BACKGROUND: As the older population increases so does the number of older psychiatric patients. Elderly psychiatric patients manifest certain specific and unique characteristics. Different subtypes of depressive syndromes exist in late-life depression, and many of these are associated with cognitive impairment. MATERIALS AND METHODS: A total of 109 depressive patients and 30 normal subjects matched by age and educational level were evaluated using a neuropsychiatric interview and an extensive neuropsychological battery. Depressive patients were classified into four different groups by SCAN 2.1 (schedules for clinical assessment in Neuropsychiatry): major depression disorder (n: 34), dysthymia disorder (n: 29), subsyndromal depression (n: 28), and depression due to mild dementia of Alzheimer's type (n: 18). RESULTS: We found significant associations (p<.05) between depressive status and demographic or clinical factors that include marital status (OR: 3.4, CI: 1.2-9.6), level of daily activity (OR: 5.3, CI: 2-14), heart disease (OR: 12.5, CI: 1.6-96.3), and high blood cholesterol levels (p:.032). Neuropsychological differences were observed among the four depressive groups and also between depressive patients and controls. Significant differences were observed in daily life activities and caregivers' burden between depressive patients and normal subjects. CONCLUSION: Geriatric depression is associated with heart disease, high cholesterol blood levels, marital status, and daily inactivity. Different subtypes of geriatric depression have particular clinical features, such as cognitive profiles, daily life activities, and caregivers' burden, that can help to differentiate among them. LIMITATIONS: The cohort referred to a memory clinic with memory complaints is a biased sample, and the results cannot be generalized to other non-memory symptomatic cohorts.Fil: Dillon, Carol. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: MacHnicki, Gerardo. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Serrano, Cecilia M.. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Rojas, Galeno. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Vazquez, Gustavo. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Allegri, Ricardo Francisco. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Erosión costera en el parque costero del sur: la importancia de proteger los humedales

La Reserva Biosfera Parque Costero Sur se desarrolla en el litoral de los partidos de Punta Indio y Magdalena, Buenos Aires, Argentina, donde existen ambientes de humedales de manera prácticamente continua a lo largo de la línea de costa. Históricamente el litoral de la Reserva ha sido afectado en numerosos sectores por la actividad humana, principalmente a través de la actividad turística y del retiro de la vegetación intermareal (comunidad del Juncal, Cagnoni et al., 1996) por los “junqueros”. El presente estudio se enmarca en el sector de la Reserva Biosfera Parque Costero Sur localizado en el litoral noreste del Partido de Punta Indio. La reserva se desarrolla dentro de la planicie costera del Río de la Plata, la cual fue generada a partir de las oscilaciones en el nivel medio del mar y de los eventos transgresivo-regresivos ocurridos durante elPleistoceno tardío y el Holoceno a partir del último máximo glacial, hace unos 18000 años (Cavallotto et al., 2004). Dicha planicie puede ser subdividida en tres unidades de paisaje principales: antigua llanura de mareas, planicie con cordones litorales y marisma, existiendo marcadas diferencias sedimentológicas entre estas unidades. La antigua llanura de mareas corresponde a una zona de topografía muy baja, actualmente desconectada del estuario, ya que se encuentra a unos 5 m sobre el nivel medio actual, pero que preserva la morfología de canales y planicies intermareales. La planicie con cordones está formada por sistemas paralelos a subparalelos de cordones de playa principalmente arenosos y conchiles y poseen una topografía más elevada que el resto de la planicie. La marisma está constituida principalmente por sedimentos arcillosos y constituye un humedal costero donde los procesos sedimentológicos e hidrológicos están principalmente regulados por la acción mareal. Los sedimentos pleistocenos loessicos se encuentran por debajo de los sedimentos de la planicie costera y afloran en la unidad de planicie continental y en una plataforma de abrasión adyacente al estuario.Fil: Cellone, Francisco Aldo. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; ArgentinaFil: Carol, Eleonora Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentin

Transmission dynamics of an insect-specific flavivirus in a naturally infected Culex pipiens laboratory colony and effects of co-infection on vector competence for West Nile virus

AbstractWe established a laboratory colony of Culex pipiens mosquitoes from eggs collected in Colorado and discovered that mosquitoes in the colony are naturally infected with Culex flavivirus (CxFV), an insect-specific flavivirus. In this study we examined transmission dynamics of CxFV and effects of persistent CxFV infection on vector competence for West Nile virus (WNV). We found that vertical transmission is the primary mechanism for persistence of CxFV in Cx. pipiens, with venereal transmission potentially playing a minor role. Vector competence experiments indicated possible early suppression of WNV replication by persistent CxFV infection in Cx. pipiens. This is the first description of insect-specific flavivirus transmission dynamics in a naturally infected mosquito colony and the observation of delayed dissemination of superinfecting WNV suggests that the presence of CxFV may impact the intensity of enzootic transmission of WNV and the risk of human exposure to this important pathogen

Clinical and economic characteristics associated with direct costs of Alzheimer's, frontotemporal and vascular dementia in Argentina

Background: The economic cost of dementia is high and can be predicted by cognitive and neuropsychiatric profiles. The differential costs of the various subtypes of dementia are unknown in Argentina, and this study therefore aimed to compare these costs. Methods: Patients with a diagnosis of dementia of Alzheimer-type (DAT), frontotemporal dementia (FTD) and vascular dementia (VaD), and their primary caregivers, were evaluated between 2002 and 2008. Results: 104 patients with dementia (DAT = 44, FTD = 34, VaD = 26) were screened and matched by age and educational level with 29 healthy subjects. Demographic variables showed no significant differences among dementia patients. The annual direct costs were US$4625 for DAT, US$4924 for FTD, and US$5112 for VaD (p > 0.05 between groups). In the post hoc analysis VaD showed higher hospitalization costs than DAT (p < 0.001). VaD exhibited lower medication costs than FTD (p < 0.001). DAT exhibited higher anti-dementia drug costs; FTD had higher psychotropic costs. In the multivariate analysis, depression, activities of daily living, and caregiver burden were correlated with direct costs (r2 = 0.76). Conclusions: The different dementia types have different costs. Overall, costs increased with the presence of behavioral symptoms, depression and functional impairment of activities of daily living.Fil: Rojas, Galeno. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Bartoloni, Leonardo Carlos. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Dillon, Carol. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Serrano, Cecilia Mariela. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Iturry, Mónica Liliana. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; ArgentinaFil: Allegri, Ricardo Francisco. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin