566 research outputs found
Prenatal diagnosis and follow-up of congenital splenic cysts
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
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
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
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 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 % 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
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
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
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 %–80 % 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 % 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 m above, in coincidence with the wind speed profile.</p
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