Costa Rica's payment for environmental services program: intention, implementation, and impact.

We evaluated the intention, implementation, and impact of Costa Rica's program of payments for environmental services (PSA), which was established in the late 1990s. Payments are given to private landowners who own land in forest areas in recognition of the ecosystem services their land provides. To characterize the distribution of PSA in Costa Rica, we combined remote sensing with geographic information system databases and then used econometrics to explore the impacts of payments on deforestation. Payments were distributed broadly across ecological and socioeconomic gradients, but the 1997-2000 deforestation rate was not significantly lower in areas that received payments. Other successful Costa Rican conservation policies, including those prior to the PSA program, may explain the current reduction in deforestation rates. The PSA program is a major advance in the global institutionalization of ecosystem investments because few, if any, other countries have such a conservation history and because much can be learned from Costa Rica's experiences.

Prevalence of MRSA and Antimicrobial Resistance of Staphylococcus aureus in Maryland Ground Meat Products

Gemstone Team Antibiotic Resistance

Phase II Archaeological Excavations at 99 Main Street, 18AP21 (Sign of the Whale), Annapolis, Maryland

Historical Annapolis Foundation (HAF) conducted terrestrial archaeological investigations at site 18AP21 in the city of Annapolis, Maryland. Excavations were carried out at this National Register site ostensibly as a Phase II project to evaluate the site and assess the need for further work. The site is at 99 Main Street in the center of downtown Annapolis, near the Annapolis waterfront. The project was carried out as part of the advanced work for the Annapolis History Center project, to be built in the adjoining buildings of 99 Main and 196 Green Streets. The buildings are the property of the Historic Annapolis Foundation and located in Maryland Research Unit 7. The excavations were undertaken by HAF, and funded by HAFF. The work was conducted for HAF and MHT, who holds an archaeological easement on the property. This preliminary phase of work included stratigraphic excavation of two testpit units. These two units revealed that the site of the existing 99 Main Street building was the location of three previous constructions. The current building at 99 Main Street, built in 1791, was preceded by an earlier brick dwelling, evidenced by a stout pier of bricks, which was attached to a wooden-sided structure that stood on a foundation of brick and stone. Ceramics indicate that these buildings date to the early-middle of the 18th century. A third structure of post-in-ground construction, evidenced by recovery of burned posts and wood fragments, likely existed prior to these, but evidence was scant. These excavations reveal that the site of 18AP21 holds potential for understanding Annapolis's early cultural developments, especially in the area of initial settlement and the origins of waterfront commerce. The assemblage of artifacts recovered includes a broad sample of common 18th century pottery such as creamware and Chinese export porcelain, and also includes some early colonial types such as tin-glazed earthenware and various red-bodied slipwares. The excavations do not provide conclusive evidence of the construction sequence. Consultation with MHT representatives indicates that further work at the site will likely be needed before modifications to the floor of the building can progress.

Probabilistic Fréchet means for time varying persistence diagrams

© 2015, Institute of Mathematical Statistics. All rights reserved.In order to use persistence diagrams as a true statistical tool, it would be very useful to have a good notion of mean and variance for a set of diagrams. In [23], Mileyko and his collaborators made the first study of the properties of the Fréchet mean in (Dp, Wp), the space of persistence diagrams equipped with the p-th Wasserstein metric. In particular, they showed that the Fréchet mean of a finite set of diagrams always exists, but is not necessarily unique. The means of a continuously-varying set of diagrams do not themselves (necessarily) vary continuously, which presents obvious problems when trying to extend the Fréchet mean definition to the realm of time-varying persistence diagrams, better known as vineyards. We fix this problem by altering the original definition of Fréchet mean so that it now becomes a probability measure on the set of persistence diagrams; in a nutshell, the mean of a set of diagrams will be a weighted sum of atomic measures, where each atom is itself a persistence diagram determined using a perturbation of the input diagrams. This definition gives for each N a map (Dp)^N→ℙ(Dp). We show that this map is Hölder continuous on finite diagrams and thus can be used to build a useful statistic on vineyards.

Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder.

Fear conditioning is an established model for investigating posttraumatic stress disorder (PTSD). However, symptom triggers may vaguely resemble the initial traumatic event, differing on a variety of sensory and affective dimensions. We extended the fear-conditioning model to assess generalization of conditioned fear on fear processing neurocircuitry in PTSD. Military veterans (n=67) consisting of PTSD (n=32) and trauma-exposed comparison (n=35) groups underwent functional magnetic resonance imaging during fear conditioning to a low fear-expressing face while a neutral face was explicitly unreinforced. Stimuli that varied along a neutral-to-fearful continuum were presented before conditioning to assess baseline responses, and after conditioning to assess experience-dependent changes in neural activity. Compared with trauma-exposed controls, PTSD patients exhibited greater post-study memory distortion of the fear-conditioned stimulus toward the stimulus expressing the highest fear intensity. PTSD patients exhibited biased neural activation toward high-intensity stimuli in fusiform gyrus (P<0.02), insula (P<0.001), primary visual cortex (P<0.05), locus coeruleus (P<0.04), thalamus (P<0.01), and at the trend level in inferior frontal gyrus (P=0.07). All regions except fusiform were moderated by childhood trauma. Amygdala-calcarine (P=0.01) and amygdala-thalamus (P=0.06) functional connectivity selectively increased in PTSD patients for high-intensity stimuli after conditioning. In contrast, amygdala-ventromedial prefrontal cortex (P=0.04) connectivity selectively increased in trauma-exposed controls compared with PTSD patients for low-intensity stimuli after conditioning, representing safety learning. In summary, fear generalization in PTSD is biased toward stimuli with higher emotional intensity than the original conditioned-fear stimulus. Functional brain differences provide a putative neurobiological model for fear generalization whereby PTSD symptoms are triggered by threat cues that merely resemble the index trauma.

Cumulative early life adversity predicts longevity in wild baboons.

In humans and other animals, harsh circumstances in early life predict morbidity and mortality in adulthood. Multiple adverse conditions are thought to be especially toxic, but this hypothesis has rarely been tested in a prospective, longitudinal framework, especially in long-lived mammals. Here we use prospective data on 196 wild female baboons to show that cumulative early adversity predicts natural adult lifespan. Females who experience ≥3 sources of early adversity die a median of 10 years earlier than females who experience ≤1 adverse circumstances (median lifespan is 18.5 years). Females who experience the most adversity are also socially isolated in adulthood, suggesting that social processes partially explain the link between early adversity and adult survival. Our results provide powerful evidence for the developmental origins of health and disease and indicate that close ties between early adversity and survival arise even in the absence of health habit and health care-related explanations.

Diseño del colector y ocurrencia de deslizamiento de pezoneras durante el ordeñe de vacas y vaquillonas : (Estudio de caso)

El objetivo de este trabajo fue comparar el número de deslizamientos de pezoneras ocurridos durante el ordeñe con colectores de diferente diseño. La diferencia entre colectores consistió en la posición de los nipples que conectan la tapa del colector con las pezoneras de los cuartos traseros de la ubre. Se utilizó un colector con nipples paralelos (P) y otro con nipples no paralelos (Np) en cada ordeñe, realizando un ordeñe con cada diseño de colector. El diseño P mejoraría el posicionamiento de las pezoneras durante el ordeñe y reduciría la ocurrencia deslizamiento en comparación con el diseño Np. Este trabajo se desarrollo en un tambo comercial en donde se evalúo el número de deslizamientos ocurridos en dos ordeñes consecutivos realizados con uno u otro diseño de colector. Se ordeñaron 411 animales divididos en dos grupos cada vez (215 vacas y 196 vaquillonas), durante cada ordeñe se observo y registró la ocurrencia de deslizamiento de pezoneras en cada animal de cada grupo. El numero de animales con deslizamientos de pezoneras fue mayor cuando se utilizó el colector Np que con P, y menor en vacas que en vaquillonas.

Caza y comercio de cueros de Tupinambis spp. en un departamento de la provincia de San Luis y la relación con los mercados mundiales y las políticas de conservación

p.187-196

Incremento de las precipitaciones (1921/1998) en el centro este de la provincia de La Pampa (Argentina)

p.193-196

Alumnos recursantes de Botánica Agrícola I : un análisis descriptivo de esta situación

p.191-196

De nietos y aves

Soluciones a los Problemas de los abuelos, estudio de las respuestas a uno de los problemas planteados en el Torneo de Matemáticas para 2º de la ESO de la Sociedad Canaria Isaac Newton de profesores de matemáticas. Actividad de resolución de problemas en una clase de 6º de Primaria.

Análisis didáctico-matemático de un error algebraico en estudiantes y profesores

La investigación tiene dos fases: 1) Se plantea a los estudiantes de primer ingreso a la Universidad Panamericana, Guadalajara, México la simplificación de la expresión algebraica ; analizándose las respuestas equivocadas con su posible origen. 2) Se hace un estudio con 7 profesores de educación media básica y media superior, en el cual, se les presenta la simplificación errónea (a la izq.) con la consigna de mencionar el origen del error y cómo le ayudarían al alumno. Alumnos cometen errores de muy diverso origen, y los profesores encuestados no siempre analizan a profundidad el origen del error cometido por este alumno.

Aprendiendo a reconocer evidencias del proceso de generalización de los estudiantes a través de un debate virtual

Este estudio tiene como objetivo examinar cómo los futuros profesores de secundaria (EPS) reconocen evidencias de la comprensión del proceso de generalización en estudiantes de secundaria. Los EPS realizaron dos tareas: (1) describir las respuestas dadas por estudiantes de secundaria a dos problemas de generalización lineal y agrupar las que reflejaban características comunes de la comprensión del proceso de generalización; (2) participar en un debate virtual sobre las características de la comprensión del proceso de generalización. Los resultados indican que la participación en el debate virtual permitió a los EPS centrar su mirada en las ideas que subyacen en el proceso de generalización (generalización cercana y lejana e intento de expresar la regla general, pasando de una estrategia aditiva a una funcional) más que en el procedimiento realizado.