972 resultados para 4-level


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We construct a nonrelativistic wave equation for spinning particles in the noncommutative space (in a sense, a theta modification of the Pauli equation). To this end, we consider the nonrelativistic limit of the theta-modified Dirac equation. To complete the consideration, we present a pseudoclassical model (a la Berezin-Marinov) for the corresponding nonrelativistic particle in the noncommutative space. To justify the latter model, we demonstrate that its quantization leads to the theta-modified Pauli equation. We extract theta-modified interaction between a nonrelativistic spin and a magnetic field from such a Pauli equation and construct a theta modification of the Heisenberg model for two coupled spins placed in an external magnetic field. In the framework of such a model, we calculate the probability transition between two orthogonal Einstein-Podolsky-Rosen states for a pair of spins in an oscillatory magnetic field and show that some of such transitions, which are forbidden in the commutative space, are possible due to the space noncommutativity. This allows us to estimate an upper bound on the noncommutativity parameter.

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In this work a series of tetrakis complexes C[Tm(acac)(4)] where C(+) = Li(+) Na(+) and K(+) countercations and acac = acetylacetonate ligand were synthesized and characterized for photoluminescence investigation The relevant aspect is that these complexes are water-free in the first coordination sphere The emission spectra of the tetrakis Tm(3+)-complexes present narrow bands characteristic of the (1)G(4)->(3)H(6) (479 nm) (1)G(4)->(3)F(4) (650 nm) and (1)G(4) ->(3)H(5) (779 nm) transitions of the Tm(3+) ion with the blue emission color at 479 nm as the most prominent one The lifetime values (tau) of the emitting (1)G(4) level of the C[Tm(acac)(4)] complexes were 344 360 and 400 ns for the Li(+) Na(+) and K(+) countercations respectively showing an increasing linear behavior versus the ionic radius of the alkaline ion An efficient intramolecular energy transfer process from the triplet state (T) of the ligands to the emitting (1)G(4) state of the Tm(3+) ion is observed This fact together with the absence of water molecules in first coordination sphere allows these tetrakis Tm(3+)-complexes to act as efficient blue light conversion molecular devices (c) 2010 Elsevier B V All rights reserved

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The objective of this research is to assess the influences of basal canker on wood properties for the kraft pulp production. The material consisted of seeded E. grandis trees classified into 4 levels of basal canker severity (0, 1, 2 and 3) and installed in three soil types classified by texture (AQ1 and AQ2 - 10 to 15% clay, and LEm2 - 26 to 35 clay). The sampling consisted of randomly selecting five trees for each for each canker severity level and soil type, totaling 60 trees (4 canker levels x 3 soil types x 5 trees). These trees were fallen and cut into sections at 0, 25, 50, 75 and 100% of the commercial height for the collection of disk and logs of wood. The results showed that the soil texture influences in the Eucalyptus canker severity and this fact should be considered when assessing the wood properties and their final destination. The texture of the soil and the severe levels of basal canker influence the wood properties, and therefore the kraft pulping.

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In this work, we report a theoretical and experimental investigation of the energy transfer mechanism in two isotypical 2D coordination polymers, (infinity)[(Tb1-xEux)(DPA)(HDPA)], where H(2)DPA is pyridine 2,6-dicarboxylic acid and x = 0.05 or 0.50. Emission spectra of (infinity)[(Tb0.95Eu0.05)(DPA)(HDPA)] and (infinity)[(Tb0.5Eu0.5)(DPA)(HDPA)], (I) and (2), show that the high quenching effect on Tb3+ emission caused by Eu3+ ion indicates an efficient Tb3+-> Eu3+ energy transfer (ET). The k(ET) of Tb3+-> Eu3+ ET and rise rates (k(r)) of Eu3+ as a function of temperature for (1) are on the same order of magnitude, indicating that the sensitization of the Eu3+5D0 level is highly fed by ET from the D-5(4) level of Tb3+ ion. The eta(ET) and R-0 values vary in the 67-79% and 7.15 to 7.93 angstrom ranges. Hence, Tb3+ is enabled to transfer efficiently to Eu3+ that can occupy the possible sites at 6.32 and 6.75 angstrom. For (2), the ET processes occur on average with eta(ET) and R-0 of 97% and 31 angstrom, respectively. Consequently, Tb3+ ion is enabled to transfer energy to Eu3+ localized at different layers. The theoretical model developed by Malta was implemented aiming to insert more insights about the dominant mechanisms involved in the ET between lanthanides ions. Calculated single Tb3+-> Eu3+ ETs are three orders of magnitude inferior to those experimentally; however, it can be explained by the theoretical model that does not consider the role of phonon assistance in the Ln(3+)-> Ln(3+) ET processes. In addition, the Tb3+-> Eu3+ ET processes are predominantly governed by dipole-dipole (d-d) and dipole-quadrupole (d-q) mechanisms.

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Symptomatic cervical spinal arteriovenous malformations (AVMs) located on the anterior aspect of the spinal cord are rare and surgical removal of these AVMs presents considerable challenges and risks. Surgical techniques to date have usually been by posterior approach and lateral dissection around the cord or via midline myelotomy, both approaches involving cord manipulation and retraction and in the latter, dissection through the spinal cord. We present two teenage patients with symptomatic anteriorly placed mid to high cervical spinal AVMs and associated aneurysm in which excision of the AVMs and aneurysm was performed by an anterior approach using vertebrectomy/corpectomy. The first case had a small perimedullary glomus-type AVM with an aneurysm on the anterior aspect of the cord at the C3/4 level; excision was performed using a single level vertebrectomy/corpectomy, the patient remaining neurologically intact. The second case had a medium-sized juvenile AVM with an aneurysm, both perimedullary and intramedullary, centred at the C5/6 level; excision was performed using a two-level vertebrectomy/corpectomy with no deterioration in the marked pre-operative tetraparesis, which at long-term follow up had improved and stabilised. Anterior approaches have been recently described for treatment of anteriorly placed cervical arteriovenous fistulas (AVFs) and an intramedullary haemangioblastoma, but not as yet for spinal AVMs. These are the first two reported cases of anteriorly situated cervical AVMs successfully removed surgically by an anterior approach and with good neurological outcomes.

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The OPERA experiment is designed to search for ν μ →ν τ oscillations in appearance mode, i.e., through the direct observation of the τ lepton in ν τ -charged current interactions. The experiment has taken data for five years, since 2008, with the CERN Neutrino to Gran Sasso beam. Previously, two ν τ candidates with a τ decaying into hadrons were observed in a subsample of data of the 2008–2011 runs. Here we report the observation of a third ν τ candidate in the τ − →μ − decay channel coming from the analysis of a subsample of the 2012 run. Taking into account the estimated background, the absence of ν μ →ν τ oscillations is excluded at the 3.4 σ level.

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The ability of public health practitioners (PHPs) to work efficiently and effectively is negatively impacted by their lack of knowledge of the broad range of evidence-based practice information resources and tools that can be utilized to guide them in their development of health policies and programs. This project, a three-hour continuing education hands-on workshop with supporting resources, was designed to increase knowledge and skills of these resources. The workshop was presented as a pre-conference continuing education program for the Texas Public Health Association (TPHA) 2008 Annual Conference. Topics included: identification of evidence-based practice resources to aid in the development of policies and programs; identification of sources of publicly available data; utilization of data for community assessments; and accessing and searching the literature through a collection of databases available to all citizens of Texas. Supplemental resources included a blog that served as a gateway to the resources explored during the presentation, a community assessment workbook that incorporates both Healthy People 2010 objectives and links to reliable sources of data, and handouts providing additional instruction on the use of the resources covered during the workshop.^ Before- and after-workshop surveys based on Kirkpatrick's 4-level model of evaluation and the Theory of Planned Behavior were administered. Of the questions related to the trainer, the workshop, and the usefulness of the workshop, participants gave "Good" to "Excellent" responses to all one question. Confidence levels overall increased a statistically significant amount; measurements of attitude, social norms, and control showed no significant differences before and after the workshop. Lastly, participants indicated they were likely to use resources shown during the workshop within a one to three month time period on average. ^ The workshop and creation of supplemental resources served as a pilot for a funded project that will be continued with the development and delivery of four 4-week long webinar-based training sessions to be completed by December 2008. ^

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"Illinois highway safety program."

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Introducción: El síndrome de agotamiento profesional o de burnout se define como una respuesta al estrés laboral crónico, afecta con frecuencia a los trabajadores del sector salud y ha sido descrito según la Organización Mundial de la Salud (OMS) como un riesgo laboral. En su desarrollo intervienen distintos factores principalmente sociodemográficos y laborales. Objetivo: Determinar la prevalencia de síndrome de agotamiento profesional y su relación con las condiciones de trabajo del personal de salud de la zona rural del Cauca. Metodología: Se realizó un estudio de corte transversal en 4 hospitales rurales nivel I, con un muestreo probabilístico aleatorio simple, para un total de 212 trabajadores, de los cuales el 74.5% fueron asistenciales y el 25.5% administrativos, Se les aplicó el cuestionario Maslash Burnout Inventory (MBI) que consta de 22 ítems y mide los 3 aspectos del síndrome: cansancio emocional, despersonalización y falta de realización personal y el cuestionario nacional de condiciones de trabajo del instituto nacional de seguridad e higiene en el trabajo de España (INSHT). Se realizó un análisis de datos en STATA versión 12. Resultados: Se encontró una prevalencia general de síndrome de agotamiento profesional de 39.7% y según cada dimensión para cansancio emocional de 21.7%, para despersonalización de 15.1% y para realización personal de 13.7%. Se halló significancia estadística con relación a la edad y baja realización personal (p=0.037), con los factores de riesgo psicolaborales por sobrecarga y cansancio emocional (p=0.020), falta de autonomía y cansancio emocional (p=0.021) entre otros. En los factores de riesgo biomecánicos por falta de iluminación y cansancio emocional (p=0.000), falta de iluminación y despersonalización (p=0.017) y falta de iluminación y síndrome en general (p=0.000). Conclusión: La prevalencia de síndrome de agotamiento profesional en el personal de salud que trabaja en zona rural del Cauca fue de 39.7%, la dimensión más determinante fue cansancio emocional seguido de despersonalización y por ultimo realización personal. Se recomienda iniciar en la institución con un programa de vigilancia epidemiológica de prevención para el agotamiento laboral e intervenir en los factores biomecánicos y factores psicolaborales.

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Background. Toll-like receptors (TLR) recognize a variety of ligands, including pathogen-associated molecular patterns and link innate and adaptive immunity. Individual receptors can be up-regulated during infection and inflammation. We examined the expression of selected TLRs at the protein level in various types of renal disease.Methods. Frozen sections of renal biopsies were stained with monoclonal antibodies to TLR-2, -4 and -9.Results. Up-regulation of the three TLRs studied was seen, although the extent was modest. TLR-2- and -4-positive cells belonged to the population of infiltrating inflammatory cells; only in the case of TLR-9 were intrinsic glomerular cells positive in polyoma virus infection and haemolytic uraemic syndrome (HUS).Conclusions. Evidence for the involvement of the three TLRs tested in a variety of human renal diseases was found. These findings add to our understanding of the role of the innate immune system in kidney disease.