409 research outputs found
Robust Sure Independence Screening for Non-polynomial dimensional Generalized Linear Models
We consider the problem of variable screening in ultra-high dimensional (of
non-polynomial order) generalized linear models (GLMs). Since the popular SIS
approach is extremely unstable in the presence of contamination and noises,
which may frequently arise in the large scale sample data (e.g., Omics data),
we discuss a new robust screening procedure based on the minimum density power
divergence estimator (MDPDE) of the marginal regression coefficients. Our
proposed screening procedure performs extremely well both under pure and
contaminated data scenarios. We also theoretically justify the use of this
marginal MDPDEs for variable screening from the population as well as sample
aspects; in particular, we prove that these marginal MDPDEs are uniformly
consistent leading to the sure screening property of our proposed algorithm. We
have also proposed an appropriate MDPDE based extension for robust conditional
screening in the GLMs along with the derivation of its sure screening property.Comment: Work in Progres
Robust sure independence screening for nonpolynomial dimensional generalized linear models
We consider the problem of variable screening in
ultra-high-dimensional generalized linear models
(GLMs) of nonpolynomial orders. Since the popular
SIS approach is extremely unstable in the presence
of contamination and noise, we discuss a new robust
screening procedure based on the minimum density
power divergence estimator (MDPDE) of the marginal
regression coefficients. Our proposed screening procedure performs well under pure and contaminated data
scenarios. We provide a theoretical motivation for the
use of marginal MDPDEs for variable screening from
both population as well as sample aspects; in particular, we prove that the marginal MDPDEs are uniformly
consistent leading to the sure screening property of
our proposed algorithm. Finally, we propose an appropriate MDPDE-based extension for robust conditional
screening in GLMs along with the derivation of its sure
screening property. Our proposed methods are illustrated through extensive numerical studies along with
an interesting real data application
Pathological cell assembly dynamics in a striatal MSN network model
Under normal conditions the principal cells of the striatum, medium spiny neurons (MSNs), show structured cell assembly activity patterns which alternate sequentially over exceedingly long timescales of many minutes. It is important to understand this activity since it is characteristically disrupted in multiple pathologies, such as Parkinson's disease and dyskinesia, and thought to be caused by alterations in the MSN to MSN lateral inhibitory connections and in the strength and distribution of cortical excitation to MSNs. To understand how these long timescales arise we extended a previous network model of MSN cells to include synapses with short-term plasticity, with parameters taken from a recent detailed striatal connectome study. We first confirmed the presence of sequentially switching cell clusters using the non-linear dimensionality reduction technique, Uniform Manifold Approximation and Projection (UMAP). We found that the network could generate non-stationary activity patterns varying extremely slowly on the order of minutes under biologically realistic conditions. Next we used Simulation Based Inference (SBI) to train a deep net to map features of the MSN network generated cell assembly activity to MSN network parameters. We used the trained SBI model to estimate MSN network parameters from ex-vivo brain slice calcium imaging data. We found that best fit network parameters were very close to their physiologically observed values. On the other hand network parameters estimated from Parkinsonian, decorticated and dyskinetic ex-vivo slice preparations were different. Our work may provide a pipeline for diagnosis of basal ganglia pathology from spiking data as well as for the design pharmacological treatments
The megalithic building of S.Erasmo di Cesi: architecture, astronomy, and landscape
Abstract. One of the most enigmatic megalithic buildings of Italy is the structure which lies on the S. Erasmo hill near Cesi, in Umbria, a huge complex encompassing an area of around 8000 square meters and enclosed by refined cyclopean walls. Although its date is uncertain, suggested dates comprise the Iron Age and archaic period, down to the third century B.C. The building’s function is also uncertain. Usually identified as a fortified structure, in fact there is a megalithic platform at the southern end of the enclosure which could have served as foundation of a temple or palace and, from the top of Monte Torre Maggiore, a complex of temples dating from the fourth century B.C. overlooks the hill. Similar combinations of megalithic buildings resting half-way to temples placed on high peaks are known to exist. In order to clarify the function of this structure and its position in relation to the surrounding landscape, with particular attention to its visibility and to the directions of visibility from the complex, as well as to the possible astronomical alignments, we present a multi-disciplinary approach to the study of the S. Erasmo complex, which includes the mapping of the sky at the various possible epochs of construction, the creation of a digital model of the landscape in forms of digital maps using Geographic Information System technologies, and a 3D model using various 3D software packages
Catalizadores de oro y oxido de cobalto para la oxidación de naftaleno y material particulado
En este trabajo se presenta un estudio de la combustión catalítica de naftaleno y material particulado, contaminantes provenientes de los motores de combustión interna, con catalizadores de óxido de cobalto y oro soportados en óxido de circonio y óxido de circonio hidratado. Se caracterizaron con técnicas fisicoquímicas (DRX, BET, FTIR). Los resultados obtenidos son promisorios, particularmente en lo referente a la aplicación de estos sistemas en la combustión de naftaleno donde se ha encontrado una alta conversión de naftaleno a CO₂ a baja temperatura (250ºC).Centro de Investigación y Desarrollo en Ciencias Aplicada
Testosterone, cortisol, and status-striving personality features: A review and empirical evaluation of the dual hormone hypothesis
Decades of research in behavioral endocrinology has implicated the gonadal hormone testosterone in the reg-
ulation of mating effort, often expressed in primates in the form of aggressive and/or status-striving behavior.
Based on the idea that neuroendocrine axes influence each other, recent work among humans has proposed that
links between testosterone and indices of status-striving are rendered conditional by the effects of glucocorti-
coids. The Dual Hormone hypothesis is one particular instance of this argument, predicting that cortisol blocks
the effects of testosterone on dominance, aggression, and risk-taking in humans. Support for the Dual Hormone
hypothesis is wide-ranging, but considerations of theoretical ambiguity, null findings, and low statistical power
pose problems for interpreting the published literature. Here, we contribute to the development of the Dual
Hormone hypothesis by (1) critically reviewing the extant literature—including p-curve analyses of published
findings; and, (2) “opening the file drawer” and examining relationships between testosterone, cortisol, and
status-striving personality features in seven previously published studies from our laboratories (total N = 718;
median N per feature = 318) that examined unrelated predictions. Results from p-curve suggest that published
studies have only 16% power to detect effects, while our own data show no robust interactions between tes-
tosterone and cortisol in predicting status-striving personality features. We discuss the implications of these
results for the Dual Hormone hypothesis, limitations of our analyses, and the development of future research
Efecto de la presencia de vapor de agua en la actividad catalítica de catalizadores de cobalto soportado sobre zirconia
El presente trabajo está dirigido al estudio de la estabilidad hidrotérmica del sistema Co/ZrO2 como catalizador de la reacción de reducción de NO empleando un hidrocarburo saturado, propano, como reductor en presencia de oxígeno. Se prepararon los catalizadores con diferentes métodos, se caracterizaron los materiales obtenidos, enfatizando el análisis de las características estructurales del soporte y de las propiedades fisicoquímicas de las especies de cobalto y se analizará la correlación entre estructura y estabilidad.Facultad de Ciencias Exacta
14q12q13.2 microdeletion syndrome: Clinical characterization of a new patient, review of the literature, and further evidence of a candidate region for CNS anomalies
Background: Chromosome 14q11-q22 deletion syndrome (OMIM 613457) is a rare contiguous gene syndrome. Two regions of overlap (RO) of the 14q12q21.1 deletion have been identified: a proximal region (RO1), including FOXG1(*164874), NKX2-1(*600635), and PAX9(*167416) and a distal region (RO2), including NKX2-1 and PAX9. We report a 6-year-old boy with mild dysmorphic facial features, global developmental delay, and hypoplasia of the corpus callosum. Methods and Results: Array-CGH analysis revealed a 14q12q13.2 microdeletion. We compared the phenotype of our patient with previously published cases in order to establish a genotype–phenotype correlation. Conclusion: The study hypothesizes the presence of a new RO, not including the previously reported candidate genes, and attempt to define the associated molecular and psychomotor/neurobehavioral phenotype. This region encompasses the distal breakpoint of RO1 and the proximal breakpoint of RO2, and seems to be associated with intellectual disability (ID), hypotonia, epilepsy, and corpus callosum abnormalities. Although more cases are needed, we speculated on SNX6(*606098) and BAZ1A(*605680) as potential candidate genes associated with the corpus callosum abnormalities
Simultaneous Proton Transfer Reaction-Mass Spectrometry and electronic nose study of the volatile compounds released by Plasmodium falciparum infected red blood cells in vitro
The discovery that Volatile Organic Compounds (VOCs) can be biomarkers for several diseases has led to the conception of their possible application as diagnostic tools. In this study, we aimed at defining of diagnostic signatures for the presence of malaria transmissible stages in infected individuals. To do this, we compared VOCs released by asexual and sexual stage cultures of Plasmodium falciparum, the deadliest species of malaria, with those emitted by uninfected red blood cells (RBCs). VOC analysis was carried out with an innovative set-up, where each sample was simultaneously analysed by proton transfer reaction time of flight mass spectrometry (PTR-ToF-MS) and an electronic nose. PTR-Tof-MS results show that sexual stages are characterized by a larger emission of hexanal, compared with uninfected or asexual stage-infected RBCs, which makes them clearly identifiable. PTR-Tof-MS analysis also detected differences in VOC composition between asexual stages and uninfected RBCs. These results have been substantially replicated by the electronic nose analysis and may open the possibility to develop sensitive and easy-to-use devices able to detect sexual parasite stages in infected individuals. This study also demonstrates that the combination of mass spectrometry with electronic noses is a useful tool to identify markers of diseases and to support the development of optimized sensors
Elaboración de galletitas saludables usando harinas de topinambur y amaranto
El topinambur (Helianthus tuberosus) es un tubérculo con alto contenido en inulina, polisacárido prebiótico empleado como ingrediente en alimentos funcionales. Por otra parte, el amaranto (Amaranthus cruentus; A.caudatus; A.hypochondriacus) es un pseudo cereal de origen andino, valorado por su contenido de proteínas y equilibrada composición en aminoácidos esenciales. A partir de ambos productos se obtienen harinas nutricionalmente diferenciadas.
El objetivo de este trabajo fue elaborar galletitas saludables con bajo contenido calórico pero con buen aporte de fibra y proteínas. Se obtuvo harina de topinambur a partir de cultivos propios (en el predio de la FICA-UNSL), y se caracterizó la misma utilizando métodos oficiales de análisis (AOAC, 1990).
Se ensayaron 8 formulaciones con distintas proporciones de harina de topinambur piel blanca de producción propia (HTPB) y harinas comerciales: harina de trigo integral y harina de amaranto. Para que las galletitas sean aptas para personas con diabetes, se debe asegurar un bajo índice glucémico, por ello, la cantidad máxima de harina de trigo integral en las formulaciones fue de un 50%. Cada 100 g de mezcla de harinas se agregó 1 g de sal, 1 g de polvo de hornear, 8 g de aceite y 30 mL de agua.
Teniendo en cuenta las características sensoriales más notorias de las galletitas (color, sabor, apariencia, textura), se seleccionaron tres formulaciones para analizar su aceptabilidad mediante un panel sensorial con panelistas no entrenados. Se encontró una preferencia significativa por las galletitas con mayor contenido de HTPB.
Al analizar la textura, se observó que la formulación con mayor contenido de HTPB presentó mayores valores de dureza, fracturabilidad y masticabilidad.
Se pudo concluir, que la harina de topinambur puede utilizarse para formular galletitas saludables con buena aceptación sensorial.Centro de Investigación y Desarrollo en Criotecnología de Alimento
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