3,967 research outputs found
Efecto de la radiación UV-C y del agua caliente en el contenido de calcio y calidad poscosecha de manzanas
To increase the storage shelf life of "Red Delicious" and "Golden Delicious" apples they were treated with UV-C irradiation at doses of 0, 5 and 15 min irradiation at 1.435 x 10E-4 W/square cm and with hot water containing 4% CaCl2 at four levels (control, dipping at 25 deg C for 10 min, dipping at 38 deg C for 5 min and dipping in 54 deg C for 1 min) in a factorial design with 4 replicates. The results showed that UV-C irradiation and dipping of fruit in hot water increased the storage life and improved fruit quality factors in "Red Delicious" and "Golden Delicious" apples at the end of cold storage. Both UV-C and hot water treatments decreased pH and total soluble solids/titratable acids ratio and increased fruit titratable acids and firmness. UV-C and hot water treatment increased fruit Ca content during storage. The results showed that UV-C and hot water treatment can retard fruit ripening and maintain fruit quality in cold storage. These treatments can also increase Ca concentration of fruit flesh and thus increase the nutritional value of the apples.Con el fin de prolongar el periodo de vida útil durante la conservación frigorífica de manzanas "Red Delicious" y "Golden Delicious", éstas se trataron con radiación UV-C en tres dosis (0, 5 y 15 min de irradiación a 1,435 x 10E-4 W/cm cuadrado) y agua caliente con CaCl2 al 4% en cuatro niveles (control 0, inmersión a 25 grados C 10 min, 38 grados C 5 min ó 54 grados C 1 min), en un diseño factorial con 4 repeticiones por tratamiento. La irradiación con UV-C y la inmersión de los frutos en agua caliente permitió alargar el periodo de conservación y mejoró la calidad de manzanas "Red Delicious" y "Golden Delicious" tras el almacenamiento en frío. Ambos tratamientos aumentaron la acidez titulable y la firmeza de los frutos, también disminuyeron el pH y la relación sólidos solubles/acidez. El tratamiento con UV-C y agua caliente incrementó el contenido en calcio de los frutos durante el almacenamiento. Los resultados muestran que estos tratamientos pueden retrasar los procesos de maduración de los frutos y mantener su calidad durante el almacenamiento frigorífico, así como aumentar el contenido en Ca de la pulpa del fruto y por tanto incrementar su valor nutricional
Retrograde Laryngeal Block: A New Technique for Awake Intubation Compared With Conventional Regional Airway Block
Introduction: Retrograde laryngeal block is a new technique that blocks complete supraglottic and glottic area by introducing catheter
retrograde from trachea to these regions.
Methods and Materials: This is a clinical trial conducted on two groups each containing 15 patients, who were candidate for awake intubation. The first group (A) underwent conventional method of airway block, by multiple injections of local anesthetic. The second group (B) underwent retrograde laryngeal block as a new method of regional airway anesthesia. In this method the catheter is inserted from cricothyriod membrane through a flexible guide wire, and then local anesthetic drug will be administered by direct vision
of tip of the catheter by employing glide scope. The catheter has three separate orifices; each will stay on distinct area of either supraglottic and glottis area which can be adjusted at any level through this area that is considered to be blocked.
Result: Both groups had hemodynamic stability during performing block. In group A we had two incidences of laryngospasm due to pain of multiple needle insertion; in group B we had no incidence of laryngospasm (P=0.1). In group A we had 5 patients with partial airway block which needed further intervention during awake intubation but in group B all the cases had complete and perfect airway block (P=0.001). Patients comfort was better in group B with single injection than group A with multiple injections
(P=0.005).
Discussion: The advantage of this method is single injection and high quality of block performance in comparison with the other technique. It can be conducted for the patients with neck pathologies that make conventional airway block impossible.
Conclusion: This method can be applied in patients with neck pathologies that make conventional block impossible
Comparison of 2D and 3D modeling for deriving effective hydraulic properties of stony soils
Stone, gravel or rock fragments that are embedded in a matrix of fine soil have a substantial effect on effective soil hydraulic and transport properties. Understanding the role of stones in soils is important not only for soil water transport processes such as infiltration, evaporation and redistribution, but also for related solute transport processes. A variety of models has been proposed in the past to predict the systematic effect of varying amounts of stones on effective saturated conductivity and water retention of a soil-stone mixture. Respective studies for unsaturated hydraulic conductivity are still missing. To test the accuracy and validity of such predictive models, and to expand them to unsaturated conductivity, the investigation of virtual porous media, which can be obtained by numerical forward modeling of water and solute transport in soil-stone mixtures is the method of choice. Furthermore, to test the postulate that effective homogeneous properties exist and can replace the heterogeneous system, the ability of a 1D model with assumed homogeneous soil properties to match “observed” state variables and fluxes of a higher-dimensional heterogeneous model under a variety of conditions is a necessary requirement. With few exceptions, such heterogeneous modeling studies have hitherto been performed only for simplified cases, i.e., either under fully saturated conditions, or with a reduced dimensionality, i.e., 2D simulations of soil/stone mixtures. In this work, we use the simulation tool HYDRUS-2D3D to investigate the systematic differences that occur when modeling partially unsaturated transient water in stony soils, based on the Richards equation. Specifically, we compare truly 3D with 2D simulations and discuss the implications for effective 1D hydraulic properties
Magnetic properties of the spin Heisenberg chain with hexamer modulation of exchange
We consider the spin-1/2 Heisenberg chain with alternating spin exchange %on
even and odd sites in the presence of additional modulation of exchange on odd
bonds with period three. We study the ground state magnetic phase diagram of
this hexamer spin chain in the limit of very strong antiferromagnetic (AF)
exchange on odd bonds using the numerical Lanczos method and bosonization
approach. In the limit of strong magnetic field commensurate with the
dominating AF exchange, the model is mapped onto an effective Heisenberg
chain in the presence of uniform and spatially modulated fields, which is
studied using the standard continuum-limit bosonization approach. In absence of
additional hexamer modulation, the model undergoes a quantum phase transition
from a gapped string order into the only one gapless L\"uttinger liquid (LL)
phase by increasing the magnetic field. In the presence of hexamer modulation,
two new gapped phases are identified in the ground state at magnetization equal
to 1/3 and 2/3 of the saturation value. These phases reveal themselves also in
magnetization curve as plateaus at corresponding values of magnetization. As
the result, the magnetic phase diagram of the hexamer chain shows seven
different quantum phases, four gapped and three gapless and the system is
characterized by six critical fields which mark quantum phase transitions
between the ordered gapped and the LL gapless phases.Comment: 21 pages, 5 figures, Journal of Physics: Condensed Matter, 24,
116002, (2012
CEQE: Contextualized Embeddings for Query Expansion
In this work we leverage recent advances in context-sensitive language models to improve the task of query expansion. Contextualized word representation models, such as ELMo and BERT, are rapidly replacing static embedding models. We propose a new model, Contextualized Embeddings for Query Expansion (CEQE), that utilizes query-focused contextualized embedding vectors. We study the behavior of contextual representations generated for query expansion in ad-hoc document retrieval. We conduct our experiments on probabilistic retrieval models as well as in combination with neural ranking models. We evaluate CEQE on two standard TREC collections: Robust and Deep Learning. We find that CEQE outperforms static embedding-based expansion methods on multiple collections (by up to 18% on Robust and 31% on Deep Learning on average precision) and also improves over proven probabilistic pseudo-relevance feedback (PRF) models. We further find that multiple passes of expansion and reranking result in continued gains in effectiveness with CEQE-based approaches outperforming other approaches. The final model incorporating neural and CEQE-based expansion score achieves gains of up to 5% in P@20 and 2% in AP on Robust over the state-of-the-art transformer-based re-ranking model, Birch
Supercapacitor management system:A comprehensive review of modeling, estimation, balancing, and protection techniques
A fast computational algorithm to evaluate large transmit-arrays
Transmit-arrays (TAs) have become popular solutions for point-to-point communications due to their lowprofile and high-efficiency. However, simulation of these large and detailed structures demands a great amount of memory and time. Here, we propose a fast algorithm to estimate the performance of a beam-steering TA to accelerate its design optimization process. The results and the required resources of the algorithm are compared with the ones of Ansys HFSS. It is shown that this algorithm can fairly evaluate the key factors of the performance of a TA within couple of minutes with memory resource of only 1 GB.info:eu-repo/semantics/acceptedVersio
Equivalent circuit modeling to design a dual-band dual linear-to-circular polarizer surface
The working principle of a thin dual-band dual-linear to circular polarizer is presented here. This polarizer not only converts incident linearly polarized (LP) waves to circularly polarized (CP) waves in two frequency bands, but it also reverses the handedness of each signal. The electromagnetic behavior of the cell is carefully analyzed and two equivalent circuit models (ECMs) are presented to model the responses of
the cell to linearly polarized waves at normal incidence. The ECMs show how utilizing interlayer coupling can be leveraged to achieve reversed CP senses in two bands using a compact design. Analytical formulas are presented to provide initial values of the ECM components including the mutual coupling inductances. We present measurement results that agree well with the full-wave simulation and the ECM results, thus validating the proposed ECM model.info:eu-repo/semantics/acceptedVersio
Effects of fish meal replacement by silkworm pupae on growth, survival and body chemical composition of rainbow trout (Oncorhynchus mykiss)
Silkworm pupae meal is a non-conventional animal protein feedstuff. It is the by-product after the silk thread has been wound off from the cocoon. To investigate the effects of animal protein on growth and survival of rainbow trout (Oncorhynchus mykiss), a sixty-day feeding experiment was conducted. Four replacement levels (0, 5, 10 and 15 percent) of silkworm pupae meal were compared using a completely random design. We used 360 juvenile rainbow trout (average weight 55±3.42g) divided into 4 groups and 3 replications, each containing 30 trout for 60 days. Sampling for nutritional effects was carried out every 10 days and at the end of the experiment, weight gain, feed conversion ratio, specific growth rate, protein and efficiency ratio were compared which showed no significant differences (P>0.05) among the treatments. Total length and survival rate were not significantly affected in the treatment groups. The highest percentage of carcass protein and the lowest percentage of carcass fat belonged to the control treatment. Our findings showed that silkworm pupae meal could replace 15% of fish meal diet in rainbow trout culture
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