Automated classification of landforms on terraces of northeast Patagonian Massif, Argentina

Se realizó una clasificación automatizada de las geoformas en terrazas del noreste del Macizo Norpatagónico, Argentina. La clasificación se realizó mediante parametrización del relieve a partir del modelo digital de elevación del proyecto Shuttle Radar Topography Mission (NASA), a través del empleo de un Sistema de Información Geográfica. En este estudio se derivaron modelos digitales como el índice de posición topográfica (TPI) y pendiente, que se emplearon como base para la clasificación. Se realizaron sucesivos ajustes en la definición del TPI y de las reglas de clasificación de geoformas, apoyados en la supervisión de la cartografía, fotografías aéreas, imágenes satelitales y observaciones en el terreno. De acuerdo con la clasificación propuesta en este estudio, el área está dominada por las geoformas pendiente abierta y planicie, que alcanzan el 45 y 33% del área total, respectivamente. Las restantes clases geomorfológicas cubren superficies menores: lomas, cerros y sierras (8%); bajos, valles en V (7,5%); valles en U (3%) y pendiente alta (2,6%).We made an automated classification of landforms on terraces of northeast Patagonian Massif, Argentina. Classification of landforms was carried out using parameterization of the relief from the Shuttle Radar Topography Mission digital elevation model within a geographical information system. Digital models such as topographic position index (TPI) and slope derived from elevation data were employed as a basis for classification. Successive adjustments were made for TPI and classification rules, which were supervised base on aerial photographs, satellite imagery and survey of land. According to the classification proposed in the present study, the area is dominated by open slope and plain landforms, reaching 45 and 33% of the total area, respectively. The remaining classes occupy smaller areas: ridges, hills and mountains (8%), low, valleys in the form of V (7.5%); valleys in the form of U (3%) and high slope (2.6%).Fil: Genchi, Sibila Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Carbone, Maria Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Respuesta hidrológica de las cuencas de drenaje que intersectan el balneario Las Grutas, Argentina

The town of Las Grutas, in a semiarid region on the north west coast of San Matías Gulf (Argentina), is intersected by two drainage basins that are activated immediately after intense rainfall events. These events generate flows capable of producing local flooding, such as the flood of April 2004. The purpose of this study is to establish the hydrologic behavior of these geoforms and the manner in which the land use interacts with them. The lack of hydrometric records necessitates the explanation and prediction of hydrologic responses through empirical approaches such as fluvial morphometry and the USDA Soil Conservation Service curve number (1972), supported by Geographical Information System technology. The study area has characteristics that favor the concentration of runoff into streams during extreme events. First-order segments play an important role in the hydrologic response, showing great potential to receive surface runoff. The effect of urbanization produces an additional runoff of 17.3% and 2.1% in the respective basins. A potential increase in the number of these extreme events in the future due to climate change may lead to more disturbances in the urbanized area. The results of the present study will contribute to the implementation of measures to mitigate the consequences of floods.La localidad de Las Grutas está emplazada en una región semiárida, en la costa Noroccidental del Golfo San Matías (Argentina) y es intersectada por dos cuencas de drenaje que responden ante eventos de precipitaciones intensas. Estos eventos generan flujos capaces de producir riesgos de inundación local, tal como la inundación de abril de 2004. El objetivo de este trabajo es establecer el comportamiento hidrográfico de dichas geoformas y la manera en el cual los usos de la tierra interactúan con ellas. La falta de registros hidrométricos conduce a explicar y predecir respuestas a través de aproximaciones empíricas como el análisis morfométrico fluvial y el número de curva del Servicio de Conservación del Suelo de los Estados Unidos (1972), apoyados en sistemas de información geográfica. El área en estudio presenta características que favorecen la concentración del escurrimiento en cauces durante eventos extremos. Los segmentos de primer orden juegan un rol importante en la respuesta hidrológica. El efecto de la urbanización produce un efecto adicional del 17.3 y 2.1% de escurrimiento en cada cuenca. El incremento potencial del número de eventos extremos en el futuro debido al cambio climático, podría conducir a mayores perturbaciones en el área urbanizada. Los resultados contribuirán a implementar medidas que mitiguen posibles consecuencias de los peligros de inundación.Fil: Genchi, Sibila Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Carbone, Maria Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; ArgentinaFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentin

Human impact on the quality of the surface waters of the Claromecó Creek mid-basin, Argentina

Los cursos fluviales de la cuenca media del Arroyo Claromecó en su recorrido atraviesan la localidad de Tres Arroyos con más de 59 000 habitantes. El objetivo de este trabajo es analizar la calidad de agua de los cursos superficiales de la cuenca media para estudiar el impacto humano en este sector del sistema fluvial. Se seleccionaron 5 estaciones de muestreo para la concentración de metales pesados en el sedimento de los cauces y en cuatro de ellas se obtuvieron valores de nutrientes en agua. Estas mediciones se realizaron durante agosto del 2007 y se repitieron durante agosto del 2009. La determinación de nutrientes se realizó mediante el uso de un autoanalizador Technicon AutoAnalyzer II secuencial y por espectrofotometría se analizó la Materia Orgánica Particulada. Los valores de nutrientes hallados presentaron mayor variabilidad entre los años 2007 y 2009. Los máximos se observaron durante el primer año de medición, mientras que el máximo de amonio se observó en el colector principal para el año 2009. Se detectaron variables superiores a los niveles guía de protección de la vida acuática, como el caso de nitratos y fosfatos en el Arroyo Claromecó, tendencia que se mantuvo en casi todos los parámetros químicos, lo que se correspondería con descargas cloacales y secundariamente industriales de las plantas procesadoras por las que atraviesa este curso fluvial en el área urbana y periurbana de la localidad de Tres Arroyos. Los sedimentos fluviales analizados presentaron valores de metales pesados bajos-intermedios. El análisis de las variables físicas y químicas del agua reflejan para los afluentes del Arroyo Claromecó las características de sustrato y la influencia del uso agrícola ganadero circundante. El curso principal presenta un predominio del uso urbano e industrial a partir del mayor aporte de nutrientes a sus aguas, provenientes de descargas domésticas directas sin tratamiento.The creeks of the middle basin of the Arroyo Claromecó cross the town of Tres Arroyos with over 59 000 inhabitants, where an industrial plant and a wastewater treatment plant city is located. The aim of this paper is to analyze the quality of surface water courses of the basin to study human impact on this sector of the river system. We selected 5 sampling stations for the concentration of heavy metals in the sediment of rivers. In four of them values of nutrients in the water were obtained. These measurements were conducted during August 2007 and repeated in August 2009. The determination of nutrients was performed using a sequential Technicon Autoanalyzer II and the Particulate OrganicMatter was analyzed by spectrophotometry. The nutrient values showed greater variability between 2007 and 2009. The maxima were observed during the first year of measurement, while the maximum of ammonium was observed in the main sewer in 2009. Variables were detected above guideline levels for the protection of aquatic life, as the case of nitrates and phosphates in the Arroyo Claromecó. This trend was maintained for almost all the chemical parameters, which would correspond to secondary sewage and industrial discharges from plants processing by the river that runs through this course in peri-urban areas of the town of Tres Arroyos. The analyzed river sediments showed low to intermediate values of heavy metals. For the tributaries of the Arroyo Claromecó, the analysis of the physical and chemical variables of water reflects substrate characteristics and the influence of surrounding agricultural livestock. The main course presents a predominance of urban and industrial use from the increased supply of nutrients to the water, that come directly from untreated domestic dischargesFil: Carbone, Maria Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: García Martínez, B.. Universidad de Sevilla. Facultad de Geografía e Historia; EspañaFil: Marcovecchio, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentin

Incidencia de la variabilidad hidrológica en la morfología de cauces del arroyo Claromecó (Buenos Aires, Argentina)

En este trabajo se pone de manifiesto la variabiliclad hidrológica del Arroyo Claromecó, asi como la configuración morfológica de 10s cauces y las márgenes cle su tramo principal y sus principales afluentes. Los resultados son entre otros, la designación de un régimen pluvial oceánico matizado, de escasa irregularidad y con un escaso coeficiente cle escorrentia; y la detección de psocesos de zaparniento, socavamiento e incisión fluvial en su tramo principal. Estos procesos estin reactivados por la ejecución de encauzamientos y rectificaciones en la red fluvial del Claromecó.This paper focuses on the hydrological variability of the Claromec6 Creek as well as on the morphology of both its courses and the banks of the main course and major affluents. The outcome of this research helped determine its rainfall pattern as oceanic- though with a very small irregularity and runoff rate- and detect the processes of excavation, subsidence and fluvial incision in the main course. These processes have been reactivated by the channelling and straightening of the Claromec6 fluvial network.Fil: Garcia Martínez, Belén. Universidad de Sevilla; EspañaFil: Carbone, Maria Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Características morfo-anatómicas de las hojas y tallos de Baccharis notosergila (Asteraceae) y su relación con el ambiente y control químico

Background and aims: Baccharis notosergila is an aggressive weed inhabiting the Salado river basin, Buenos Aires province, Argentina. The aims were: to analyze the morpho-anatomy and histochemistry of aerial vegetative organs in order to understand the adaptation strategies that ensure its survival, as well as to expand knowledge on traits determining resistance to the control methods applied. M&M: The material collected was prepared and examined with conventional techniques of microscopy. Histochemical tests were performed. Results: The major features found were small and deciduous leaves; uniseriate epidermis with massive and striate cuticle; stomata at level or slightly above the other epidermal cells and glandular trichomes secreting oily substances; stomata on both surfaces and isobilateral mesophyll. Starch, phenolic and lipophilic substances, and resins were identified in leaves and stems, and calcium oxalate crystals in leaves, stems and capitate trichomes. Conclusions: The aerial vegetative organs features of B. notosergila explain its tolerance to the unfavorable conditions of the Salado river basin area, as well as its competitive ability over others species of the natural prairie. The reduced and deciduous leaves, the epidermal traits, and chemical substances found constitute a physical and chemical barrier reducing dehydration as well as the penetration of the herbicides applied for its control. Botanical knowledge of B. notosergila is the basis to develop new and appropiate management methods for this species.Introducción y objetivos: Baccharis notosergila es una maleza agresiva que habita la Depresión del Salado, provincia Buenos Aires, Argentina. Los objetivos de este trabajo fueron: analizar la morfo-anatomía e histoquímica de los órganos vegetativos aéreos para entender las estrategias de adaptación que aseguran su sobrevivencia, así como profundizar el conocimiento sobre los caracteres que determinan la resistencia a los métodos de control. M&M: El material recolectado fue preparado y analizado con técnicas convencionales para microscopía. Se realizaron pruebas histoquímicas para identificar almidón, resinas, polifenoles y sustancias lipofílicas. Resultados: Los principales caracteres encontrados fueron las hojas pequeñas y caedizas, anfistomáticas con mesofilo isobilateral; la epidermis uniseriada, cutícula masiva y estriada, estomas a nivel o ligeramente elevados y tricomas glandulares que secretan sustancias oleosas. Los tests histoquímicos dieron reacción positiva para almidón, taninos y sustancias lipofílicas en las hojas y tallos; polifenoles, resinas y aceites fueron identificados en los conductos y se hallaron cristales de oxalato de calcio en las hojas, tallos y tricomas capitados. Conclusiones: Las características de los órganos vegetativos aéreos de B. notosergila explican su tolerancia a las condiciones desfavorables del área de la Depresión del Salado, así como su alta habilidad competitiva y predominancia sobre otras especies de la pradera natural. Las hojas pequeñas y deciduas, sus características epidérmicas y sustancias químicas encontradas constituyen una barrera física y química para la deshidratación así como la penetración de los herbicidas aplicados para su control. El conocimiento botánico de B. notosergila es la base para el diseño y desarrollo de nuevos y apropiados métodos para el manejo de esta especie.Facultad de Ciencias Agrarias y ForestalesInstituto de Fisiología Vegeta

Prospective Multicenter Study of Community-Associated Skin and Skin Structure Infections due to Methicillin-Resistant Staphylococcus aureus in Buenos Aires, Argentina

Background. Community-associated methicillin-resistant Staphylococcus aureus(CAMRSA) is now the most common cause of skin and skin structure infections (SSSI) in several world regions. In Argentina prospective, multicenter clinical studies have only been conducted in pediatric populations. Objective. Primary: describe the prevalence, clinical and demographic characteristics of adult patients with community acquired SSSI due to MRSA; secondary: molecular evaluation of CA-MRSA strains. Patients with MRSA were compared to those without MRSA. Material and Methods. Prospective, observational, multicenter, epidemiologic study, with molecular analysis, conducted at 19 sites in Argentina (18 in Buenos Aires)between March 2010 and October 2011. Patients were included if they were ≥ 14 years, were diagnosed with SSSI, a culture was obtained, and there had no significant healthcare contact identified. A logistic regression model was used to identify factors associated with CA-MRSA. Pulse field types, SCCmec, and PVL status were also determined. Results. A total of 311 patients were included. CA-MRSA was isolated in 70% (218/311) of patients. Clinical variables independently associated with CA-MRSA were: presence of purulent lesion (OR 3.29; 95%CI 1.67, 6.49) and age <50 years (OR 2.39; 95%CI 1.22, 4.70). The vast majority of CA-MRSA strains causing SSSI carried PVL genes (95%) and were SCCmec type IV. The sequence type CA-MRSA ST30 spa t019 was the predominant clone. Conclusions. CA-MRSA is now the most common cause of SSSI in our adult patients without healthcare contact. ST30, SCCmec IV, PVL+, spa t019 is the predominant clone in Buenos Aires, Argentina.Fil: Lopez Furst, Maria Jose. Sanatorio Municipal Dr. Julio Méndez, Ciudad Autónoma de Buenos Aires; Argentina;Fil: de Vedia, Lautaro. Gobierno de la Ciudad de Buenos Aires. Htal.de Infecciosas F.j. Muñiz; Argentina;Fil: Fernandez, Silvina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica. Cat.de Microbiologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Gardella, Noella Mariel. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica. Cat.de Microbiologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Ganaha, Cristina. Pcia. de Buenos Aires. Hospital Vicente López y Planes, Gral. Rodríguez; Argentina;Fil: Prieto, Sergio. Provincia de Buenos Aires. Hospital Nuestra Señora de Luján; Argentina;Fil: Carbone, Edith. Hospital Aeronautico Central; Argentina;Fil: Lista, Nicolás. Gobierno de la Ciudad de Buenos Aires. Htal.de Infecciosas F.j. Muñiz; Argentina;Fil: Rotryng, Flavio. Universidad Abierta Interamericana; Argentina;Fil: Morera, Graciana I.. Hospital Dr. Jose Cullen; Argentina;Fil: Mollerach, Marta Eugenia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica. Cat.de Microbiologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Stryjewski, Martin E.. Centro de Educaciones Medicas E Investig.Clinica "Norberto Quirno"; Argentina

Magnetic nanosystem for cancer therapy using oncocalyxone A, an antitomour secondary metabolite isolated from a Brazilian plant

none14siThis paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series of pharmacological properties: antioxidant, cytotoxic, analgesic, anti-inflammatory, antitumor and antiplatelet. Onco A was associated with magnetite nanoparticles in order to obtain magnetic properties. The components of MO-20 were characterized by XRD, FTIR, TGA, TEM and Magnetization curves. The MO-20 presented a size of about 30 nm and globular morphology. In addition, drug releasing experiments were performed, where it was observed the presence of the anomalous transport. The results found in this work showed the potential of onco A for future applications of the MO-20 as a new magnetic drug release nanosystem for cancer treatment.openBarreto, Antônio C.H.; Santiago, Vivian R.; Freire, Rafael M.; Mazzetto, Selma E.; Denardin, Juliano C.; Mele, Giuseppe; Cavalcante, Igor M.; Ribeiro, Maria E.N.P.; Ricardo, Nágila M.P.S.; Gonçalves, Tamara; Carbone, Luigi; Lemos, Telma L.G.; Pessoa, Otília D.L.; Fechine, Pierre B.A.*Barreto, Antônio C. H.; Santiago, Vivian R.; Freire, Rafael M.; Mazzetto, Selma E.; Denardin, Juliano C.; Mele, Giuseppe; Cavalcante, Igor M.; Ribeiro, Maria E. N. P.; Ricardo, Nágila M. P. S.; Gonçalves, Tamara; Carbone, Luigi; Lemos, Telma L. G.; Pessoa, Otília D. L.; Fechine, Pierre B. A

Surgical site infection after caesarean section. Space for post-discharge surveillance improvements and reliable comparisons

Surgical site infections (SSI) after caesarean section (CS) represent a substantial health system concern. Surveying SSI has been associated with a reduction in SSI incidence. We report the findings of three (2008, 2011 and 2013) regional active SSI surveillances after CS in community hospital of the Latium region determining the incidence of SSI. Each CS was surveyed for SSI occurrence by trained staff up to 30 post-operative days, and association of SSI with relevant characteristics was assessed using binomial logistic regression. A total of 3,685 CS were included in the study. A complete 30 day post-operation follow-up was achieved in over 94% of procedures. Overall 145 SSI were observed (3.9% cumulative incidence) of which 131 (90.3%) were superficial and 14 (9.7%) complex (deep or organ/space) SSI; overall 129 SSI (of which 89.9% superficial) were diagnosed post-discharge. Only higher NNIS score was significantly associated with SSI occurrence in the regression analysis. Our work provides the first regional data on CS-associated SSI incidence, highlighting the need for a post-discharge surveillance which should assure 30 days post-operation to not miss data on complex SSI, as well as being less labour intensive

Community-facility linkage models and maternal and infant health outcomes in Malawi’s PMTCT/ART program: a cohort study

Background: In sub-Saharan Africa, 3 community-facility linkage (CFL) models—Expert Clients, Community Health Workers (CHWs), and Mentor Mothers—have been widely implemented to support pregnant and breastfeeding women (PBFW) living with HIV and their infants to access and sustain care for prevention of mother-to-child transmission of HIV (PMTCT), yet their comparative impact under real-world conditions is poorly understood. Methods and findings: We sought to estimate the effects of CFL models on a primary outcome of maternal loss to follow-up (LTFU), and secondary outcomes of maternal longitudinal viral suppression and infant “poor outcome” (encompassing documented HIV-positive test result, LTFU, or death), in Malawi’s PMTCT/ART program. We sampled 30 of 42 high-volume health facilities (“sites”) in 5 Malawi districts for study inclusion. At each site, we reviewed medical records for all newly HIV-diagnosed PBFW entering the PMTCT program between July 1, 2016 and June 30, 2017, and, for pregnancies resulting in live births, their HIV-exposed infants, yielding 2,589 potentially eligible mother–infant pairs. Of these, 2,049 (79.1%) had an available HIV treatment record and formed the study cohort. A randomly selected subset of 817 (40.0%) cohort members underwent a field survey, consisting of a questionnaire and HIV biomarker assessment. Survey responses and biomarker results were used to impute CFL model exposure, maternal viral load, and early infant diagnosis (EID) outcomes for those missing these measures to enrich data in the larger cohort. We applied sampling weights in all statistical analyses to account for the differing proportions of facilities sampled by district. Of the 2,049 mother–infant pairs analyzed, 62.2% enrolled in PMTCT at a primary health center, at which time 43.7% of PBFW were ≤24 years old, and 778 (38.0%) received the Expert Client model, 640 (31.2%) the CHW model, 345 (16.8%) the Mentor Mother model, 192 (9.4%) ≥2 models, and 94 (4.6%) no model. Maternal LTFU varied by model, with LTFU being more likely among Mentor Mother model recipients (adjusted hazard ratio [aHR]: 1.45; 95% confidence interval [CI]: 1.14, 1.84; p = 0.003) than Expert Client recipients. Over 2 years from HIV diagnosis, PBFW supported by CHWs spent 14.3% (95% CI: 2.6%, 26.1%; p = 0.02) more days in an optimal state of antiretroviral therapy (ART) retention with viral suppression than women supported by Expert Clients. Infants receiving the Mentor Mother model (aHR: 1.24, 95% CI: 1.01, 1.52; p = 0.04) and ≥2 models (aHR: 1.44, 95% CI: 1.20, 1.74; p < 0.001) were more likely to undergo EID testing by age 6 months than infants supported by Expert Clients. Infants receiving the CHW and Mentor Mother models were 1.15 (95% CI: 0.80, 1.67; p = 0.44) and 0.84 (95% CI: 0.50, 1.42; p = 0.51) times as likely, respectively, to experience a poor outcome by 1 year than those supported by Expert Clients, but not significantly so. Study limitations include possible residual confounding, which may lead to inaccurate conclusions about the impacts of CFL models, uncertain generalizability of findings to other settings, and missing infant medical record data that limited the precision of infant outcome measurement. Conclusions: In this descriptive study, we observed widespread reach of CFL models in Malawi, with favorable maternal outcomes in the CHW model and greater infant EID testing uptake in the Mentor Mother model. Our findings point to important differences in maternal and infant HIV outcomes by CFL model along the PMTCT continuum and suggest future opportunities to identify key features of CFL models driving these outcome differences

Contracts in distributed systems

We present a parametric calculus for contract-based computing in distributed systems. By abstracting from the actual contract language, our calculus generalises both the contracts-as-processes and contracts-as-formulae paradigms. The calculus features primitives for advertising contracts, for reaching agreements, and for querying the fulfilment of contracts. Coordination among principals happens via multi-party sessions, which are created once agreements are reached. We present two instances of our calculus, by modelling contracts as (i) processes in a variant of CCS, and (ii) as formulae in a logic. With the help of a few examples, we discuss the primitives of our calculus, as well as some possible variants.Comment: In Proceedings ICE 2011, arXiv:1108.014