566 research outputs found

    Prenatal diagnosis and follow-up of congenital splenic cysts

    Get PDF
    Los quistes esplénicos congénitos son entidades poco frecuentes, particularmente en la edad pediátrica. En la literatura especializada existen pocos casos publicados con diagnóstico durante el período prenatal. Los autores describen 2 casos clínicos, identificados por ecografía prenatal a las 34 y 30 semanas de gestación, y su evolución posnatal hasta su resolución espontánea a los 5 meses y a los 2 años de vida, respectivamente. Se revisa la etiología, clínica y evolución de esta patología.Congenital splenic cysts are uncommon entities, especially in children. Few cases diagnosed in the prenatal period have been reported in the literature. We describe two cases that were identified by prenatal sonography at 34 and 30 gestational weeks. Their follow- up until spontaneous full regression at 5 months and 2 years, respectively, is discussed. The etiology, clinical findings, and clinical course of this entity are reviewed

    Fábrica magnética de los diques permo-triásicos del área de La Esperanza, macizo norpatagónico, Argentina

    Get PDF
    Se presentan los resultados preliminares de un estudio de anisotropía de susceptibilidad magnética (ASM) en diques de composiciones ácidas y básicas que intrusionan a rocas del Complejo Plutónico La Esperanza (Provincia de Río Negro, Macizo Norpatagónico, Argentina), con el fin de entender su mecanismo de emplazamiento y posibles edades relativas. El mismo fue complementado con estudios de mineralogía magnética y petrografía. Se distinguen diversas facies composicionales y texturales en los diques. El portador magnético más destacado sería magnetita multi-dominio. Se observa una buena correlación entre la fábrica magnética y el rumbo de las estructuras, pudiéndose asignar esto a direcciones de flujo y ascenso magmático.Preliminary results from anisotropy of magnetic susceptibility (AMS) studies of acid and basic dikes intruding the La Esperanza Plutonic Complex (Rio Negro province, North Patagonian Massif, Argentina) are presented, with the purpose of understanding their emplacement mechanism and possible relative ages. These studies were complemented with magnetic mineralogy and petrographic analysis. Several types are distinguished, both compositional and textural. The most important magnetic carrier is interpreted to be multi-domain magnetite. A very good correlation is observed between the magnetic fabric of the dikes, and their attitudes, which is interpreted to reflect magmatic flow and emplacement kinematics.Fil: Miguez, Maximilano R.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Martínez Dopico, Carmen Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotopica; ArgentinaFil: Rapalini, Augusto Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Lopez, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotopica; ArgentinaFil: Luppo, Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; Argentin

    Evolutionary ecomorphology of the Falkland Islands wolf Dusicyon australis

    Get PDF
    The Falkland Islands wolf Dusicyon australis is an extinct canid that was once the only endemic terrestrial mammal to inhabit the Falkland Islands. There is still a puzzling picture of the morphological adaptations of this wolf that quickly evolved from its mainland fossil ancestor: Dusicyon avus. We employ a geometric morphometric approach to identify patterns of skull shape variation in extant canids and Dusicyon spp. The Falkland Islands wolf and its fossil ancestor show a more carnivorous feeding morphology than other South American foxes, and they cluster morphologically with jackals. This supports convergence in skull shape between Dusicyon and Old World canids, although the convergence is not as strong as that exhibited by their sister hyper- and hypocarnivorous taxa

    Application of an improved global-scale groundwater model for water table estimation across New Zealand

    Get PDF
    Many studies underline the importance of groundwater assessment at the larger, i.e. global, scale. The groundwater models used for these assessments are dedicated to the global scale and therefore not often applied for studies in smaller areas, e.g. catchments, because of their simplifying assumptions. In New Zealand, advanced numerical groundwater flow models have been applied in several catchments. However, that application is piecemeal: only for a limited amount of aquifers and through a variety of groundwater model suites, formats, and developers. Additionally, there are large areas where groundwater models and data are sparse. Hence, an inter-catchment, inter-regional, or nationwide overview of important groundwater information, such as the water table, does not exist. The investment needed to adequately cover New Zealand with high-resolution groundwater models in a consistent approach would be significant and is therefore not considered possible at this stage. This study proposes a solution that obtains a nationwide overview of groundwater that bridges the gap between the (too-)expensive advanced local models and the (too-)simple global-scale models. We apply an existing, global-scale, groundwater flow model and improve it by feeding in national input data of New Zealand terrain, geology, and recharge, and by slight adjustment of model parametrisation and model testing. The resulting nationwide maps of hydraulic head and water table depths show that the model points out the main alluvial aquifers with fine spatial detail (200&thinsp;m grid resolution). The national input data and finer spatial detail result in better and more realistic variations of water table depth than the original, global-scale, model outputs. In two regional case studies in New Zealand, the hydraulic head shows excellent correlation with the available groundwater level data. Sensitivity and other analyses of our nationwide water tables show that the model is mostly driven by recharge, model resolution, and elevation (gravity), and impeded by the geology (permeability). The use of this first dedicated New Zealand-wide model can aid in provision of water table estimates in data-sparse regions. The national model can also be used to solve inconsistency of models in areas of trans-boundary aquifers, i.e. aquifers that cover more than one region in New Zealand. Comparison of the models, i.e. the national application (National Water Table model: NWT) with the global model (Equilibrium Water Table model: EWT), shows that most improvement is achieved by feeding in better and higher-resolution input data. The NWT model still has a bias towards shallow water tables (but less than the EWT model because of the finer model resolution), which could only be solved by feeding in a very high resolution terrain model that incorporates drainage features. Although this is a model shortcoming, it can also be viewed as a valuable indicator of the pre-human water table, i.e. before 90&thinsp;% of wetlands were drained for agriculture since European settlement in New Zealand. Calibration to ground-observed water level improves model results but can of course only work where there are such data available. Future research should therefore focus on both model improvements and more data-driven, improved estimation of hydraulic conductivity, recharge, and the digital elevation model. We further surmise that the findings of this study, i.e. successful application of a global-scale model at smaller scales, will lead to subsequent improvement of the global-scale model equations.</p

    Acquisitions Everywhere: Modeling an Acquisitions Data Standard to Connect a Distributed Environment

    Get PDF
    Acquisitions functions remain operationally crucial in providing access to paid information resources, but data formats and workflows utilized within library acquisitions remain primarily within the traditional integrated library system (ILS). As libraries have evolved to use distributed systems to manage information resources, so too must acquisitions functions adapt to an environment that may include the ILS, e‐resource management systems (ERMS), institutional repositories (IR), and other digital asset management systems (DAMS). This presentation is intended to articulate a vision for applying standards‐based practice—as already employed for resource description—to acquisitions functions in a variety of metadata schema and systems. Utilization of standards will be demonstrated in the proposal of a core acquisitions element set that can exist in any system, with proofs of concept including demonstration of the element set within MODS, JSON, and how it may be reflected within the ILS and ERMS. Building on these proofs of concept in recording interoperable acquisitions data will be an explanation of possible applications, including an exploration of more robust support for semantic web technologies. In particular, this presentation will explore how this element set could utilize published linked datasets, such as the North Carolina State University Organization Name Linked Data and Global Open Knowledgebase (GOKb) linked data service, to provide more accurate and efficient identity management

    Nitrogen Fertilizer Suppresses Mineralization of Soil Organic Matter in Maize Agroecosystems

    Get PDF
    The possibility that N fertilizer increases soil organic matter (SOM) mineralization and, as a result, reduces SOM stocks has led to a great debate about the long-term sustainability of maize-based agroecosystems as well as the best method to estimate fertilizer N use efficiency (FNUE). Much of this debate is because synthetic N fertilizer can positively or negatively affect SOM mineralization via several direct and indirect pathways. Here, we test a series of hypotheses to determine the direction, magnitude, and mechanism of N fertilizer effect on SOM mineralization and discuss the implications for methods to estimate FNUE. We measured the effect of synthetic N fertilizer on SOM mineralization via gross ammonification at two long-term experiments in central and southern Iowa, USA with replicated plots of continuous maize that received one of three “historical” N fertilizer rates (zero, moderate or high) from 1999 to 2014. In 2015, prior to our measurements, we split the historical N fertilizer rate plots into two subplots that received either the site-specific agronomic optimum N rate or zero N fertilizer. At the onset of rapid maize N uptake, N fertilizer reduced gross ammonification by 13–21% (2–5 kg NH4-N ha−1 d−1). A companion laboratory experiment rejected the hypothesis that differences in net primary productivity between fertilized and unfertilized treatments explained the negative effect of N fertilizer on SOM mineralization. Moreover, the NH4+ pool size was negatively correlated with the gross ammonification rate (r2 = 0.85, p \u3c 0.001). Thus, we conclude that NH4+ -N fertilizer had a direct suppressive effect on SOM mineralization. These results demonstrate that the direct effect of N fertilizer on microbial activity can exceed the indirect effects of N fertilizer via large changes in NPP that alter organic matter inputs, soil temperature and moisture content. The magnitude of this effect and specificity to NH4+ -N has significant implications for fertilizer management as well as the measurement and modeling of agroecosystem N dynamics including FNUE

    On the assessment of the moisture transport by the Great Plains low-level jet

    Get PDF
    Low-level jets (LLJs) can be defined as wind corridors of anomalously high wind speed values located within the first kilometre of the troposphere. These structures are one of the major meteorological systems in the meridional transport of moisture on a global scale. In this work, we focus on the southerly Great Plains low-level jet, which plays an important role in the moisture transport balance over the central United States. The Gulf of Mexico is the main moisture source for the Great Plains low-level jet (GPLLJ), which has been identified as a key factor for rainfall modulation over the eastern and central US. The relationship between moisture transport from the Gulf of Mexico to the Great Plains and precipitation has been well documented in previous studies. Nevertheless, a large uncertainty still remains in the quantification of the moisture amount actually carried by the GPLLJ. The main goal of this work is to address this question. For this purpose, a relatively new tool, the regional atmospheric Weather Research and Forecasting Model with 3-D water vapour tracers (WRF-WVT; Insua-Costa and Miguez-Macho, 2018) is used together with the Lagrangian model FLEXPART to estimate the load of precipitable water advected within the GPLLJ. Both models were fed with data from ERA Interim. From a climatology of jet intensity over a 37-year period, which follows a Gaussian distribution, we select five cases for study, representing the mean and 1 and 2 standard deviations above and below it. Results show that the jet is responsible for roughly 70&thinsp;%–80&thinsp;% of the moisture transport occurring in the southern Great Plains when a jet event occurs. Furthermore, moisture transport by the GPLLJ extends to the north-east US, accounting for 50&thinsp;% of the total in areas near the Great Lakes. Vertical distributions show the maximum of moisture advected by the GPLLJ at surface levels and maximum values of moisture flux about 500&thinsp;m above, in coincidence with the wind speed profile.</p
    corecore