2,689 research outputs found
Factors Influencing Student Selection of a Collegiate Aviation Program
This study aims to identify the most influential characteristics that drive undergraduate students to select collegiate aviation flight programs in the US. Using preference aggregation techniques, a list of the most influential attributes is created as a result of the investigation
Scaling of the elastic contribution to the surface free energy of a nematic on a sawtoothed substrate
We characterize the elastic contribution to the surface free energy of a
nematic in presence of a sawtooth substrate. Our findings are based on
numerical minimization of the Landau-de Gennes model and analytical
calculations on the Frank-Oseen theory. The nucleation of disclination lines
(characterized by non-half-integer winding numbers) in the wedges and apexes of
the substrate induces a leading order proportional to qlnq to the elastic
contribution to the surface free energy density, q being the wavenumber
associated with the substrate periodicity.Comment: 7 pages, 6 figures, accepted for publication in Physical Review
Metabolic and Stress Responses in Senegalese Soles (Solea senegalensis Kaup) Fed Tryptophan Supplements: E ects of Concentration and Feeding Period
The objective of this study was to assess the impact of di erent dietary Trp concentrations on
the stress and metabolism response of juvenile Senegalese soles (Solea senegalensis). Fish (38.1 1.9 g)
were fed di erent Trp-enriched feeds (0%, 1% and 2% Trp added) for two and eight days, and later
exposed to air stress for three min. Samples were taken pre- and 1 h post-stress (condition). Plasma
cortisol, lactate, glucose and proteins were significantly a ected by the sampling time, showing higher
values at 1 h post-stress. Trp concentration in food also had significant e ects on lactate and glucose
levels. However, the feeding period did not a ect these parameters. Post-stress values were higher
than in the pre-stress condition for every plasma parameter, except for lactate in two days and 1% Trp
treatment. Nevertheless, cortisol, glucose and lactate did not vary significantly between pre- and
post-stress samplings in fish fed the 1% Trp-enriched diet for two days. The lack of variability in
cortisol response was also due to the high pre-stress value, significantly superior to pre-stress control.
The exposure time to Trp feeding did not significantly a ect any enzyme activity; however, Trp added
and condition influenced protein-related enzyme activities. In spite of decreasing stress markers,
Trp-enriched diets altered the protein metabolism
Hippocampal long-term potentiation is disrupted during expression and extinction but is restored after reinstatement of morphine place preference
Learned associations between environmental cues and morphine use play an important role in the maintenance and/or relapse of opioid addiction. Although previous studies suggest that context-dependent morphine treatment alters glutamatergic transmission and synaptic plasticity in the hippocampus, their role in morphine conditioned place preference (CPP) and reinstatement remains unknown. We investigated changes in synaptic plasticity and NMDAR expression in the hippocampus after the expression, extinction, and reinstatement of morphine CPP. Here we report that morphine CPP is associated with increased basal synaptic transmission, impaired hippocampal long-term potentiation (LTP), and increased synaptic expression of the NR1 and NR2b NMDAR subunits. Changes in synaptic plasticity, synaptic NR1 and NR2b expression, and morphine CPP were absent when morphine was not paired with a specific context. Furthermore, hippocampal LTP was impaired and synaptic NR2b expression was increased after extinction of morphine CPP, indicating that these alterations in plasticity may be involved in the mechanisms underlying the learning of drug–environment associations. After extinction of morphine CPP, a priming dose of morphine was sufficient to reinstate morphine CPP and was associated with LTP that was indistinguishable from saline control groups. In contrast, morphine CPP extinguished mice that received a saline priming dose did not show CPP and had disrupted hippocampal LTP. Finally, we found that reinstatement of morphine CPP was prevented by the selective blockade of the NR2b subunit in the hippocampus. Together, these data suggest that alterations in synaptic plasticity and glutamatergic transmission play an important role in the reinstatement of morphine CPP
Evaluation of an integrated system for classification, assessment and comparison of services for long-term care in Europe: the eDESDE-LTC study
The harmonization of European health systems brings with it a need for tools to allow the standardized collection of information about medical care. A common coding system and standards for the description of services are needed to allow local data to be incorporated into evidence-informed policy, and to permit equity and mobility to be assessed. The aim of this project has been to design such a classification and a related tool for the coding of services for Long Term Care (DESDE-LTC), based on the European Service Mapping Schedule (ESMS). Methods. The development of DESDE-LTC followed an iterative process using nominal groups in 6 European countries. 54 researchers and stakeholders in health and social services contributed to this process. In order to classify services, we use the minimal organization unit or "Basic Stable Input of Care" (BSIC), coded by its principal function or "Main Type of Care" (MTC). The evaluation of the tool included an analysis of feasibility, consistency, ontology, inter-rater reliability, Boolean Factor Analysis, and a preliminary impact analysis (screening, scoping and appraisal). Results: DESDE-LTC includes an alpha-numerical coding system, a glossary and an assessment instrument for mapping and counting LTC. It shows high feasibility, consistency, inter-rater reliability and face, content and construct validity. DESDE-LTC is ontologically consistent. It is regarded by experts as useful and relevant for evidence-informed decision making. Conclusion: DESDE-LTC contributes to establishing a common terminology, taxonomy and coding of LTC services in a European context, and a standard procedure for data collection and international comparison
Introducing mobile edge computing capabilities through distributed 5G Cloud Enabled Small Cells
Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtualised resources. On the other hand, mobile edge computing makes use of processing and storage capabilities close to the air interface in order to deploy optimised services with minimum delay. The confluence of both trends is a hot topic in the definition of future 5G networks. The full centralisation of both technologies in cloud data centres imposes stringent requirements to the fronthaul connections in terms of throughput and latency. Therefore, all those cells with limited network access would not be able to offer these types of services. This paper proposes a solution for these cases, based on the placement of processing and storage capabilities close to the remote units, which is especially well suited for the deployment of clusters of small cells. The proposed cloud-enabled small cells include a highly efficient microserver with a limited set of virtualised resources offered to the cluster of small cells. As a result, a light data centre is created and commonly used for deploying centralised eNB and mobile edge computing functionalities. The paper covers the proposed architecture, with special focus on the integration of both aspects, and possible scenarios of application.Peer ReviewedPostprint (author's final draft
Dysregulated Erythroid Mg2+ Efflux in Type 2 Diabetes
CEECIND/01053/2017
UIDB/04647/2020
UIDP/04647/2020Hyperglycemia is associated with decreased Mg2+ content in red blood cells (RBC), but mechanisms remain unclear. We characterized the regulation of Mg2+ efflux by glucose in ex vivo human RBC. We observed that hemoglobin A1C (HbA1C) values correlated with Na+-dependent Mg2+ efflux (Na+/Mg2+ exchange) and inversely correlated with cellular Mg content. Treatment of cells with 50 mM D-glucose, but not with sorbitol, lowered total cellular Mg (2.2 ± 0.1 to 2.0 ± 0.1 mM, p < 0.01) and enhanced Na+/Mg2+ exchange activity [0.60 ± 0.09 to 1.12 ± 0.09 mmol/1013 cell × h (flux units, FU), p < 0.05]. In contrast, incubation with selective Src family kinase inhibitors PP2 or SU6656 reduced glucose-stimulated exchange activation (p < 0.01). Na+/Mg2+ exchange activity was also higher in RBC from individuals with type 2 diabetes (T2D, 1.19 ± 0.13 FU) than from non-diabetic individuals (0.58 ± 0.05 FU, p < 0.01). Increased Na+/Mg2+ exchange activity in RBC from T2D subjects was associated with lower intracellular Mg content. Similarly increased exchange activity was evident in RBC from the diabetic db/db mouse model as compared to its non-diabetic control (p < 0.03). Extracellular exposure of intact RBC from T2D subjects to recombinant peptidyl-N-glycosidase F (PNGase F) reduced Na+/Mg2+ exchange activity from 0.98 ± 0.14 to 0.59 ± 0.13 FU (p < 0.05) and increased baseline intracellular Mg content (1.8 ± 0.1 mM) to normal values (2.1 ± 0.1 mM, p < 0.05). These data suggest that the reduced RBC Mg content of T2D RBC reflects enhanced RBC Na+/Mg2+ exchange subject to regulation by Src family kinases and by the N-glycosylation state of one or more membrane proteins. The data extend our understanding of dysregulated RBC Mg2+ homeostasis in T2D.publishersversionpublishe
Breather trapping and breather transmission in a DNA model with an interface
We study the dynamics of moving discrete breathers in an interfaced piecewise
DNA molecule.
This is a DNA chain in which all the base pairs are identical and there
exists an interface such that the base pairs dipole moments at each side are
oriented in opposite directions.
The Hamiltonian of the Peyrard--Bishop model is augmented with a term that
includes the dipole--dipole coupling between base pairs. Numerical simulations
show the existence of two dynamical regimes. If the translational kinetic
energy of a moving breather launched towards the interface is below a critical
value, it is trapped in a region around the interface collecting vibrational
energy. For an energy larger than the critical value, the breather is
transmitted and continues travelling along the double strand with lower
velocity. Reflection phenomena never occur.
The same study has been carried out when a single dipole is oriented in
opposite direction to the other ones.
When moving breathers collide with the single inverted dipole, the same
effects appear. These results emphasize the importance of this simple type of
local inhomogeneity as it creates a mechanism for the trapping of energy.
Finally, the simulations show that, under favorable conditions, several
launched moving breathers can be trapped successively at the interface region
producing an accumulation of vibrational energy. Moreover, an additional
colliding moving breather can produce a saturation of energy and a moving
breather with all the accumulated energy is transmitted to the chain.Comment: 15 pages, 11 figure
Role of Na+ transporters HKT1;1 and HKT1;2 in tomato salt tolerance. I. Function loss of cheesmaniae alleles in roots and aerial parts
We wish to thank Elena Sanchez Romero (EEZ-CSIC) for her technical assistance, the Scientific Instrumentation Service at EEZ-CSIC, Granada, for their ICP-OES mineral analysis and Michael O'Shea for proofreading the manuscript. The study was funded by grant AGL201782452-C2-1R (A.B.) and grant AGL2017-82452-C2-2R (M.J.A.), both from the Spanish Ministerio de Ciencia e Innovacion/Agencia Estatal de Investigacion, MCIN/AEI/10.13039/501100011033, and FEDER "Una manera de hacer Europa", as well as grant ACCESP2018 (J.A.T.) from the University of Granada. J.E. was supported by a JAE Intro-CSIC grant, JAEINT_19_00566.We analyzed the physiological impact of function loss on cheesmaniae alleles at the HKT1;1 and HKT1;2 loci in
the roots and aerial parts of tomato plants in order to determine the relative contributions of each locus in the
different tissues to plant Na+/K+ homeostasis and subsequently to tomato salt tolerance. We generated different
reciprocal rootstock/scion combinations with non-silenced, single RNAi-silenced lines for ScHKT1;1 and
ScHKT1;2, as well as a silenced line at both loci from a near isogenic line (NIL14), homozygous for the Solanum
cheesmaniae haplotype containing both HKT1 loci and subjected to salinity under natural greenhouse conditions.
Our results show that salt treatment reduced vegetative growth and altered the Na+/K+ ratio in leaves and
flowers; negatively affecting fruit production, particularly in graft combinations containing single silenced
ScHKT1;2- and double silenced ScHKT1;1/ScHKT1;2 lines when used as scion. We concluded that the removal of
Na+ from the xylem by ScHKT1;2 in the aerial part of the plant can have an even greater impact than that on Na+
homeostasis at the root level under saline conditions. Also, ScHKT1;1 function loss in rootstock greatly reduced
the Na+/K+ ratio in leaf and flower tissues, minimized yield loss under salinity. Our results suggest that, in
addition to xylem Na+ unloading, ScHKT1;2 could also be involved in Na+ uploading into the phloem, thus
promoting Na+ recirculation from aerial parts to the roots. This recirculation of Na+ to the roots through the
phloem could be further favoured by ScHKT1;1 silencing at these roots.Spanish Ministerio de Ciencia e Innovacion/Agencia Estatal de Investigacion AGL2017-82452-C2-1R
AGL2017-82452-C2-2RFEDER "Una manera de hacer Europa" MCIN/AEI/10.13039/501100011033University of Granada ACCESP2018JAE Intro-CSIC grant JAEINT_19_0056
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