Isotope effects in the vibrational deactivation of large molecules

Collisional deactivation of highly vibrationally excited gas phase toluene‐d8 and benzene‐d6 pumped at 248 nm, has been investigated by monitoring the time resolved infrared fluorescence from the C–D stretch modes near 4.3 μm. For toluene‐d8, energy transfer data were obtained for about 20 collider gases, including unexcited toluene‐d8; for benzene‐d6, only a few colliders were investigated. For both systems the data were analyzed by an inversion technique that converts the fluorescence decay to the bulk average energy, from which is calculated the average energy transferred per collision, 〈〈ΔE〉〉inv. Data obtained earlier for benzene‐d0 were reanalyzed and the revised results are reported. Results for both normal and deuterated excited species show 〈〈ΔE〉〉inv to be nearly directly proportional to the vibrational energy 〈〈E〉〉inv of the excited molecule from 5 000 to 25 000 cm−1. However, for pure toluene‐d8, benzene‐d6, and a few other collider gases at high energies, the slope of the 〈〈ΔE〉〉inv vs 〈〈E〉〉inv curve is reduced and even becomes negative at sufficiently high energies. The results obtained for normal and deuterium‐containing species are discussed in terms of possible quantum effects and mechanisms for energy transfer. In particular, it is considered likely that V–T/R energy transfer dominates over V–V, and the lowest frequency vibrational modes are the conduits for the energy transfer, in agreement with results for small molecules. Attention is called to a fundamental difference between classical and quantum statistics and how this difference may adversely affect classical trajectory simulations of large molecules.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69901/2/JCPSA6-97-3-1809-1.pd

Excitation of CO2 by energy transfer from highly vibrationally excited benzene derivatives

The time‐resolved infrared fluorescence technique has been used to study V–V and V–T/R energy transfer to carbon dioxide from highly excited benzene, benzene‐d6, toluene, and toluene‐d8. The highly vibrationally excited aromatics in the electronic ground state are obtained by radiationless transitions after pumping with a KrF laser at 248 nm to the S1 excited electronic level. The V–V energy transfer from the excited parent to the asymmetric stretch mode of CO2 was measured by observing the characteristic emission of CO@B|2 near 4.3 μm. From these measurements, the probability per collision of formation of CO∗2 was determined as a function of the internal energy in the excited aromatic. In all cases investigated, this probability is ≤0.1% at the initial excitation energy of 40 000 cm−1 and it is approximately directly proportional to the vibrational energy of the excited aromatic. The total concentration of CO@B|2 produced as a result of the many collisions needed to totally deactivate the excited aromatic amounted to >5% of the initial concentration of the excited aromatic and the quantitative values obtained are in excellent agreement with other work.A simple dipole–dipole interaction model is shown to explain the observed magnitude of V–V energy transfer and it is used to predict the amount of energy transferred to the bending mode of CO2. A key feature of this model is that the states of the highly vibrationally excited polyatomic are assumed to be broadened by rapid intramolecular vibrational redistribution of energy. In addition to the V–V energy‐transfer measurements, the average energy lost per collision by the excited aromatic was determined as a function of the vibrational energy of the aromatic, and the rate constants were determined for CO∗2 deactivation by the nondeuterated species. For the deuterated species, the results implicated a contribution from resonant V–V transfer between the C–D stretch modes and the asymmetric stretch mode of CO2. The overall results for the CO2 collider gas indicate that V–V energy transfer contributes a relatively small portion of the total energy transfer, and that portion can be described with the dipole–dipole interactions model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71252/2/JCPSA6-95-11-8108-1.pd

Reactant states model: Predicted k(E,J) for NO2(2A1)→O(3P)+NO(2Π), based on spectroscopic data

High‐order spectroscopic data for the reactant are used exclusively to determine both the sum of open reactive channels and the density of states, which are used in a statistical theory to predict dissociation rate constants. Practical methods are introduced for calculating sums of reactive channels and densities of states, when couplings among all degrees of freedom are included. An empirical method is described for reconciling spectroscopic parameters with known dissociation energies (also determined spectroscopically). The predicted k(E,J)’s and thermal k∞(T) for NO2 dissociation are in good agreement with experimental data, especially when the effects of electronically excited states are included. The predicted low pressure thermal rate constants are generally in fair agreement with experiment, although a slightly different temperature dependence is calculated; this discrepancy is probably due to the absence of unknown higher order spectroscopic terms and to the crude corrections made for excited electronic states. When high order spectroscopic (or theoretical) data are available and when the effects due to excited electronic states are considered, this theory is useful for predicting, fitting, and interpreting unimolecular rate data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70846/2/JCPSA6-91-4-2239-1.pd

Cyclone-anticyclone asymmetry in rotating thin fluid layers

We report of a series of laboratory experiments and numerical simulations of freely-decaying rotating turbulent flows confined in domains with variable height. We show that the vertical confinement has important effects on the formation of large-scale columnar vortices, the hallmark of rotating turbulence, and in particular delays the development of the cyclone-anticyclone asymmetry. We compare the experimental and numerical results face-to-face, showing the robustness of the results.Comment: 12 pages, 10 figure

Evaluation of Removed and Recycled Mineral Nutrients in Italian Commercial Persimmon Orchards

Persimmon is a typical fruit crop of the Mediterranean region and, since it is considered a minor species, little information is available on its nutrients need. In the present experiment, it was estimated the quantity of removed and recycled nutrients by Kaki Tipo and Rojo Brillante, the two main varieties of persimmon grown in Emilia-Romagna region (Po Valley, Italy). Plants from ten mature orchards were selected and harvested; organs (leaves in summer, fruits at harvest, abscissed leaves, roots and skeleton) biomass and mineral composition were determined. The yearly uptake of macronutrients was similar for the 2 varieties, accounting for (kg/ ha): N 89-91, P 10-11, K 79-91, Ca 132-162, Mg 22-26 and S 9. While K was mostly found in fruits, Ca and Mg were mainly partitioned to leaves. Among micronutrients, Mn and Fe showed the highest values (1.1–1.3 and 1.2–2.1 kg/ha, respectively), followed by B (370 g/ha), while Cu and Zn showed the smallest amounts (less 100 g/ha). Nitrogen, Ca, Mg and S were those more recycled than removed, while K showed an opposite trend; among the microelements, the annual recycled fractions of B and Mn were higher than that removed

Time dependent thermal lensing measurements of V–T energy transfer from highly excited NO2

The time dependent thermal lensing technique has been used to measure the vibrational relaxation of NO2 (initially excited at 21 631 cm−1) by Ar, Kr, and Xe. The energy transfer analysis was carried out in terms of 〈〈ΔE〉〉, the bulk average energy transferred per collision. This quantity was found to have a very strong dependence on vibrational energy, with a marked increase at energies greater than about 10 000 cm−1, where several electronic excited states (2B2, 2B1, and 2A2) mix with the ground state (2A1). This effect may be due to large amplitude vibrational motions associated with the coupled electronic states. Even at low energies, deactivation is faster than in other triatomic systems, probably because NO2 is an open shell molecule and electronic curve crossings provide efficient pathways for vibrational deactivation. The V–T rate constant for deactivation of NO2(010) by argon is estimated to be (5.1±1.0)×10−14 cm3 s−1. Results obtained for NO@B|2–NO2 collisions gave 〈〈ΔE〉〉 values in good agreement with literature results from fluorescence quenching experiments, indicating that V–T may be more important than V–V energy transfer in the quenching process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70683/2/JCPSA6-92-8-4793-1.pd

Tecnicatura en Gestión y Administración Universitaria. Universidad Nacional de Santiago del Estero

La administración de las universidades latinoamericanas desde la creación de la primera Universidad en 1538, ha seguido los modelos que se han ido imponiendo en las distintas etapas de la administración pública. Ya que el siglo XXI es considerado como el “siglo del conocimiento”, es primordial la formación de recursos humanos, capacitados para gerenciar la transformación que necesitan las instituciones universitarias. En las nuevas organizaciones, Mintzberg (1979) analiza, qué es el “ajuste mutuo” o coordinación entre las personas, y sugiere que se deben formar nuevos profesionales, así como, capacitar y actualizar a los antiguos. En este marco, el personal profesionalizado contribuirá a que la institución aumente su capacidad de adaptación al cambiante mundo moderno, lo que redundará en la actualización del uso de las nuevas tecnologías y en el mejoramiento de la calidad y eficiencia de los procesos administrativos. Por ello, es que proponemos la Carrera: “Tecnicatura en Gestión y Administración Universitaria”. El proyecto se enmarca dentro de los modelos abiertos de acceso y de transformación permanentes que permite que los nuevos técnicos-profesionales contribuyan a revertir el actual modelo organizacional estático y cerrado, en un modelo capaz de producir cambios en el proceso de retroalimentación. Se prevé además que el personal de servicio egresado, deba actualizarse permanentemente mediante cursos y planes de capacitación, ya que los cambios constantes y acelerados de la universidad y de su entorno, así lo exigen. La característica principal del proyecto, es que genera un entrenamiento laboral interactivo, en servicio y para el servicio (en el sentido que lo administrativo esta orientado al servicio de la gestión) y es la Universidad la demandante de sus egresados. La carrera, con una duración de tres años y una carga horaria de 1800 horas, es de modalidad semipresencial y está organizada en dos áreas: de las Competencias o Conocimientos Generales y de las Competencias o Conocimientos Específicos. En la primera, se desarrollarán las habilidades básicas de la comunicación: la expresión oral y escrita, la interpretación, el cálculo y la informática. En la segunda, se privilegiará la capacidad los conocimientos organizacionales, administrativos, normativos, de planificación y de gestión. Se contempla además, la realización de una Residencia en el área de sus competencias. El perfil del egresado es el de un profesional capaz de integrar equipos de trabajo, colaborar en la determinación y ejecución de las políticas de la institución, detectar y resolver problemas, formular propuestas alternativas de cambio y responder creativamente ante situaciones nuevas en lo institucional, profesional y comunitario y Tener una actitud favorable hacia la capacitación y el perfeccionamiento permanente

PROGRAMA DE POSTGRADO “ESPECIALIZACIÓN Y MAESTRIA EN GESTION DE LA EDUCACIÓN SUPERIOR” – ESCUELA DE INNOVACIÓN EDUCATIVA (EIE)-UNIVERSIDAD NACIONAL DE SANTIAGO DEL ESTERO (UNSE).

El programa de postgrado :“Especialización y Maestría en Gestión de la Educación Superior” de la UNSE, fue creado en 1999 por Resol del H.C.S. Nº 083, con habilitación provisoria del Ministerio de Educación por Res Nº 906/99, mientras que la CONEAU, no lo acreditó. Esto generó una crisis de confianza, que determinó la paralización de las actividades, por lo que a partir de junio de 2002, se llevaron a cabo acciones tendientes a recrear las carreras de postgrado. En el nuevo diseño, se tuvieron en cuenta las observaciones de la CONEAU, así como los relevamientos realizados a estudiantes, docentes, graduados y autoridades. Esto nos llevó a concebir que las carreras debían estar dentro de la estructura de una Unidad Académica como la Escuela de Innovación Educativa, permitiendo mantener la pertinencia y continuidad, entre el grado que allí se dicta y los programas de postgrado propuestos. El proyecto tiene estrecha relación con la función universitaria de transmitir un conocimiento interdisciplinario sobre la gestión de la Educación Superior. Para ello, es necesario la formación de recursos humanos calificados, que produzcan los cambios necesarios en la gestión y organización educativa. Se establecen dos ciclos: la Especialidad y la Maestría en Gestión de la Educación Superior. En el primer ciclo: la Especialización, hemos considerado cuatro dimensiones: una teórica, una orientada a la gestión, una a los recursos de la Educación Superior y una de aplicación en donde se consideran aspectos de organización, administración, normativos y de gestión de recursos. El objetivo es la capacitación en aspectos teóricos de la gestión de la Educación Superior y el perfil, es el de gestor especializado. En el segundo ciclo: la Maestría, complementará la formación del Especialista, y se justifica en la demanda de recursos humanos que puedan producir cambios en la organización y en el currículo, optimizando la calidad institucional y gestando nuevos modelos y funciones en los sistemas de educación superior. El perfil del Magíster será el de un experto en gestión de la educación superior, que conoce los fundamentos de las teorías y enfoques que deben aplicarse en la resolución de problemas; que pueda diagnosticar, diseñar políticas académicas e investigaciones sobre el funcionamiento de las instituciones. El ciclo de Especialización es de un año académico, para el dictado de los cursos y elaboración del trabajo final, con una carga horaria de 420 hs. El ciclo de Maestría, también de un año académico, tiene una carga horaria de 720 hs., incluyendo las destinadas a la elaboración de la Tesis de Maestría. Estos postgrados cuentan con el respaldo institucional de las Universidades Nacionales del Norte Grande y de las Universidades Nacionales de Mar del Plata y Tres de Febrero, con quienes se han firmado acuerdos de cooperación

Stress-Free Two-Way Shape Memory Effect of Poly(ethylene glycol)/ Poly(epsilon-caprolactone) Semicrystalline Networks

In this work, poly(ethylene glycol) (PEG)/poly(epsilon- caprolactone) (PCL) semicrystalline networks were prepared by photo-cross-linking of methacrylated macromonomers with different molecular weights and in different proportions to obtain amphiphilic materials capable of displaying properly designed shape memory effects. Networks based on PCL 10 kDa and PEG 3 kDa showed suitable thermal and mechanical properties with well-separated crystallization and melting regions to achieve a self-standing two-way shape memory effect. Particularly, after the application of a specific thermomechanical history, these materials are capable of cyclically changing their shape between two configurations upon cooling-heating cycles in the absence of any external load applied. The effect of the composition of the networks and of the employed thermomechanical parameters, such as the applied strain and the actuation temperature, was investigated to shed light on the shape memory mechanism for this class of materials, which are considered promising for applications in the biomedical field and as reversible actuators for soft robotics

Evaluation of plant derivatives of Meliaceae family as a source of nitrogen for trees

Soil application of fresh organic matter is a way to increase soil organic matter and provide nutrients to trees. The effect of application of organic matter depends on the interaction among soil, root and microbial biomass. The aim of this research was to evaluate the potential release of N for hybrid GF677 (P. persica x P. dulcis) uptake, of 6 neemcakes available on the Italian market compared with fresh leaves of Melia azedarach, an ornamental tree that grows in the area of investigation. The release of N, and consequently root uptake was related to C:N ratio, the lower the ratio the higher the N concentration in plant tissues and plant growth. Using the 15N isotope technique, we found that up to 30% of the N applied with fresh Melia leaves, was accumulated in the tree, however the mineral N concentration in soil and plant and plant growth was not affected by the application of plant derivatives