Download Citation on ResearchGate | Selección de abejas africanizadas para producción de propóleo | Algunas colonias de abejas Apis mellifera producen. Full Text Available El objetivo del estudio fue comparar la producción de miel y los niveles de Varroa destructor entre colonias de abejas africanizadas (AA. identificacion de las abejas africanizadas de America del Sur []. De Santis, L . Cornejo, L.G.. Access the full text: NOT AVAILABLE. Lookup the document at.

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Tiempo para un cambio. En la reunion celebrada en diciembre dei ano pasado informe al Consejo de mi deseo de terminar mi contrato como Director General de la ESO una vez que fuera aprobado el proyecto dei VLT, que se espera sucedera hacia fines de este aAo. Cuando fue renovada mi designacion hace tres aAos, el Consejo conocia mi intencion de no completar los cinco aAos dei contrato debido a mi deseo de disponer de mas tiempo para otras actividades.

Ahora, una vez terminada la fase preparatoria para el VLT, Y habiendose presentado el proyecto formalmente al Consejo el dia 31 de marzo, y esperando su muy probable aprobacion antes dei termino de este ano, me parece que el 10 de enero de presenta una excelente fecha para que se produzca un cambio en la administracion de la ESO.

In this fiscal year, we first examined the relationship between the availability of alternative fuels and station infrastructure.

Specifically, we studied how electric vehicle charging infrastructure affects the ability of EVs to compete with vehicles that rely on mature, conventional petroleum-based fuels. Last, we began analysis of impacts of alternative energy technologies on Class 8 trucks to isolate those that may most efficaciously advance HDV efficiency and petroleum use reduction goals. Generating para -water from para -hydrogen: A novel conceptual approach is described that is based on the transfer of hyperpolarization from para -hydrogen in view of generating a population imbalance between the two spin isomers of H 2 O.

The spin order transfer is expected to be most efficient at avoided level africanizadaas.

The highest achievable enrichment levels of para – and ortho-water are discussed. Separating para and ortho water.

Water exists as two nuclear-spin isomers, para and ortho, determined by the overall spin of its two hydrogen nuclei. For isolated water molecules, the conversion between these isomers is forbidden and they act as different molecular species. Yet, these species are not readily separated, and no pure para sample has been produced. Accordingly, little is known about their specific physical and chemical properties, conversion mechanisms, or interactions.

The production of isolated samples of both spin isomers is demonstrated in pure beams of para and ortho water in their respective absolute ground state.

These single-quantum-state samples are ideal targets for unraveling spin-conversion mechanisms, for precision spectroscopy and fundamental symmetry-breaking studies, and for spin-enhanced applications, for example laboratory astrophysics and astrochemistry or hypersensitized NMR experiments.

Nonrelativistic para -Lorentzian mechanics. The corresponding dynamics is developed. Most of the experimental support of special relativity is reconsidered in the light of the new theory.

It is concluded that the relativity of simultaneity has so far not been tested. Programa de conservacion para aves migratorias neotropicales. Mas de especies de aves terrestres migran a Norte America durante la epoca reproductiva para aprovechar los sistemas templados. No obstante, las aves migratorias neotropicales pasan la mayor parte de su ciclo de vida en los habitat tropicales y subtropicales de paises latinoamericanos y caribefios donde viven en una asociacion cercana con las aves residentes.

Nonclassical and semiclassical para -Bose states. Motivated by the proposal to simulate para -Bose oscillators in a trapped-ion setup [C. Huerta Alderete and B. A 95, The states spanning these bases can be experimentally realized in the trapped-ion simulation via time evolution. The para -Bose states show both nonclassical and semiclassical statistics on their Fock state distribution, asymmetric field quadrature variances, and do not minimize the uncertainty relation for the field quadratures.

These properties are analytically controlled by the para -Bose order and the evolution time; both parameters might be feasible for fine tuning in the trapped-ion quantum simulation. A para -Water Dopant in para -Hydrogen. We present the first simulation study of bosonic clusters doped with an asymmetric top molecule. The path-integral Monte Carlo method with the latest methodological advance in treating rigid-body rotation [Noya, E.

The growth pattern of the doped clusters is similar in nature to that of pure clusters. The para -water molecule appears to rotate freely in the cluster. The presence of para -water substantially quenches the superfluid response of para -hydrogen with respect to the space-fixed frame.


Ortho- para -hydrogen equilibration on Jupiter. Voyager IRIS observations reveal that the Jovian para -hydrogen fraction is not in thermodynamic equilibrium near the NH3 cloud top, implying that a vertical gradient exists between the high-temperature equilibrium value of 0. The height-dependent para -hydrogen profile is obtained using an anisotropic multiple-scattering radiative transfer model.

A vertical correlation is found to exist between the location of the para -hydrogen gradient and the NH3 cloud, strongly suggesting that paramagnetic conversion on NH3 cloud particle surfaces is the dominant equilibration mechanism. Below the NH3 cloud layer, the para fraction is constant with depth and equal to the high-temperature equilibrium value of 0.

The degree of cloud-top equilibration appears to depend on the optical depth of the NH3 cloud layer. Belt-zone variations in the para -hydrogen profile seem to be due to differences in the strength of the vertical mixing.

Superoxide reaction with tyrosyl radicals generates para -hydroperoxy and para -hydroxy derivatives of tyrosine. Tyrosine-derived hydroperoxides are formed in peptides and proteins exposed to enzymatic or cellular sources of superoxide and oxidizing species as a result of the nearly diffusion-limited reaction between tyrosyl radical and superoxide. However, the structure of these products, which informs their reactivity in biology, has not been unequivocally established. We report here the complete characterization of the products formed in the addition of superoxide, generated from xanthine oxidase, to several peptide-derived tyrosyl radicals, formed from horseradish peroxidase.

RP-HPLC, LC-MS, and NMR experiments indicate that the primary stable products of superoxide addition to tyrosyl radical are para -hydroperoxide derivatives para relative to the position of the OH in tyrosine that can be reduced to the corresponding para -alcohol.

In the case of glycyl-tyrosine, a stable 3- 1-hydroperoxyoxocyclohexa-2,5-dienyl -L-alanine was formed. In tyrosyl-glycine and Leu-enkephalin, which have N-terminal tyrosines, bicyclic indolic para -hydroperoxide derivatives were formed 2S,3aR,7aR -3a-hydroperoxyoxo-2,3,3a,6,7,7a-hexahydro-1H-indolecarboxylic acid by the conjugate addition of the free amine to the cyclohexadienone.

It was also found that significant amounts of the para -OH derivative were generated from the hydroxyl radical, formed on exposure of tyrosine-containing peptides to Fenton conditions. The para -OOH and para -OH derivatives are much more reactive than other tyrosine oxidation products and may play important roles in physiology and disease.

Para -hydrogen perspectives in hyperpolarized NMR. The first instance of para -hydrogen induced polarization PHIP in an NMR experiment was serendipitously observed in the s while investigating a hydrogenation reaction Seldler et al.

Remarkably a theoretical investigation of the applicability of para -hydrogen as a hyperpolarization agent was being performed in the ‘s thereby quickly providing a theoretical basis for the PHIP-effect Bowers and Weitekamp, [2]. The discovery of signal amplification by a non-hydrogenating interaction with para -hydrogen has recently extended the interest to exploit the PHIP effect, as it enables investigation of compounds without structural alteration while retaining the advantages of spectroscopy with hyperpolarized compounds [5].

abejas africanizadas para: Topics by

Africaniadas this article we xfricanizadas place more emphasis africqnizadas the future applications of the method while only briefly discussing the efforts that have been made in the understanding of the phenomenon and the development of the method so far. Producing and quantifying enriched para -H2. The production of enriched para -H 2 is useful for many scientific applications, but the technology for producing and measuring para -H 2 is not yet widespread. We also discuss para -H 2 storage and back conversion rates, and improvements to three techniques thermal conductance, NMR, and solid hydrogen impurity spectroscopy used to quantify the para -H 2 enrichment.

Dipolar induced para -hydrogen-induced polarization. Analytical expressions for the signal enhancement in solid-state PHIP NMR spectroscopy mediated by homonuclear dipolar interactions and single pulse or spin-echo excitation are developed and simulated numerically.

It is shown that an efficient enhancement of the africanziadas NMR signal in solid-state NMR studies of chemisorbed hydrogen on surfaces is possible. Employing typical reaction efficacy, enhancement-factors of ca.

This result has important consequences for the practical application of the method, since it potentially allows the design of an in-situ flow setup, where the para -hydrogen is adsorbed and desorbed from catalyst surfaces inside the NMR magnet.

identificacion de las abejas africanizadas de America del Sur

Time domain para hydrogen induced polarization. Para hydrogen induced polarization PHIP is a powerful hyperpolarization technique, which increases the NMR sensitivity by several orders of magnitude. However the hyperpolarized signal is created as an anti-phase signal, which necessitates high magnetic field homogeneity and spectral resolution in the conventional PHIP schemes. This hampers the application of PHIP enhancement africainzadas many fields, as for example in food science, materials science or MRI, where low B 0 -fields or low B 0 -homogeneity do decrease spectral resolution, africabizadas to potential extinction if in-phase and anti-phase hyperpolarization signals cannot be resolved.


As low field TD-spectrometers are commonly used in industry or biomedicine for the relaxometry of oil-water mixtures, food, nano-particles, or other systems, we compare two variants of para -hydrogen induced polarization with data-evaluation in the time domain TD-PHIP.

The results africanizafas that the time-domain detection of PHIP-enhanced signals opens up new application areas for low-field PHIP-hyperpolarization, such as non-invasive africanzadas detection or new contrast agents and biomarkers in low-field Magnetic Resonance Imaging MRI.

Cooling by Para -to-Ortho-Hydrogen Conversion.

Catalyst speeds conversion, increasing capacity of solid hydrogen cooling system. In radial-flow catalytic converter, para -hydrogen is converted to equilibrium mixture of para -hydrogen and ortho-hydrogen as it passes through porous cylinder of catalyst. Addition of catalyst increases capacity of hydrogen sublimation cooling systems for radiation detectors. A quarter of a century ago, in Octoberthe first africxnizadas cord injury center in Switzerland was opened at Geneva University Hospital.

At that time all para – and tetraplegics were classified as “high-risk” patients. The available resources for diagnostic aficanizadas were limited to clinical examination and neuroradiological assessment subsequently improved by the introduction of tomography and gas myelography. A great many patients suffered a deteriorated neurological level due to inadequate, multiple transfers between hospitals.

Most patients who are paralyzed following a road-traffic accident show severe polytrauma. Their chances of survival and functional recovery have greatly improved in recent years due to efficient emergency transport by helicopter, admission to an intensive care unit respiratory therapy, prophylactic anticoagulation, gastrointestinal cytoprotection, prevention of pressure sores, etc.

identificacion de las abejas africanizadas de America del Sur [1979]

Evaluation of the spine and spinal cord by NMR and CT scan allows precise assessment of the extent of CNS damage and provides additional guide-lines regarding efficient surgical reposition and spinal fusion. Ongoing experimental research in neurophysiology and neurobiochemistry of the brain and spinal cord is presently yielding some interesting results which hold out new hopes for functional recovery in some specific types of incomplete spinal cord trauma.

Polymorphism and Modulation of Para -Substituted l-Phenylalanine. The methyl-substituent in para -methyl-l-phenylalanine has, in contrast to fluorine, no polar interactions with protons of neighboring molecules, which might allow for the well-defined modulation of the crystal structure at K.

Para athletes are a high-risk population for inadequate dietary intake leading to insufficiencies in nutrients important to athletic performance. This is partly due to minimal support and resources, especially in sport nutrition education, combined with limited prior nutrition knowledge and risks associated with different impairment types. Inadequate energy, carbohydrate, protein, iron, and vitamin D status are of particular concern in Para athletes. Assessment of these key nutrients, along with sport nutrition education, is needed to empower Para athletes with the knowledge to understand their individual nutrition needs and maximize athletic performance.

Cooling by conversion of para to ortho-hydrogen. The cooling capacity of a solid hydrogen cooling system is significantly increased by exposing vapor created during evaporation of a solid hydrogen mass to a catalyst and thereby accelerating the endothermic para -to-ortho transition of the vapor to equilibrium hydrogen. Catalyst such as nickel, copper, iron or metal hydride gels of films in a low pressure drop catalytic reactor are suitable for accelerating the endothermic para -to-ortho conversion.

Para hydrogen equilibration in the atmospheres of the outer planets. The thermodynamic behavior of the atmospheres of the Jovian planets is strongly dependent on the extent to which local thermal equilibration of the ortho and para states of molecular hydrogen is achieved.

Voyager IRIS data from Jupiter imply substantial departures of the para hydrogen fraction from equilibrium in the upper troposphere at low latitudes, but with values approaching equilibrium at higher latitudes.

Data from Saturn are less sensitive to the orth- para ratio, but suggest para hydrogen fractions near the equilibrium value. Above approximately the K temperature level, para hydrogen conversion can enhance the efficiency of convection, resulting in a substantial increase in overturning times on all of the outer planets.