1,761 research outputs found
Deuterium-deuterium nuclear cross-sections in insulator and metallic environments
The three-dimensional Thomas-Fermi (TF) model is used to simulate the
variation of the d+d to t + p cross-section at low impact energies, when the
target deuterium nucleus is embedded in metallic or insulator environments.
Comparison of the computational results to recent experiments demonstrates that
even though the TF model can explain some increase in the low energy cross
section for metallic host, a full explanation of the experimental results is
still lacking. Possible reasons for the disagreement are discussed.Comment: 6 pages;6 figures. Accepted for publication in Eur. Phys. Jour.
Alpha decay rate enhancement in metals: An unlikely scenario
It has been recently suggested that one might drastically shorten the alpha
lifetime of nuclear waste products, if these are embedded in metals at low
temperatures. Using quantum mechanical tunneling arguments, we show that such
an effect is likely to be very small, if present at all.Comment: RevTeX4. 5 pages, 1 figure. Accepted by Nucl. Phys.
Numerical modelling of the quantum-tail effect on fusion rates at low energy
Results of numerical simulations of fusion rate d(d,p)t, for low-energy
deuteron beam, colliding with deuterated metallic matrix (Raiola et al. Phys.
Lett.B 547 (2002) 193 and Eur. Phys J. A 13 (2002) 377) confirm analytical
estimate given in Coraddu et al. nucl-th/0401043, taking into account quantum
tails in the momentum distribution function of target particles, and predict an
enhanced astrophysical factor in the 1 keV region in qualitative agreement with
experiments.Comment: 6 pages, without figure
Empirical eigenfunctions: application in unsteady aerodynamics
Mención Internacional en el título de doctorThe main aim of modal decompositions is to obtain a set of functions which can describe
in a compact way the variability contained in a set of observables/data. While this
can be easily obtained by means of the eigenfunctions of the operator from which the
observables depends, the empirical eigenfunctions allow to obtain a similar result from
a set of data, without the knowledge of the problem operator. In Fluid Mechanics and
related sciences one of the most prominent techniques to obtain empirical eigenfunctions
is referred to as Proper Orthogonal Decomposition (POD).
This thesis contains applications of the empirical eigenfunctions to (Experimental)
Aerodynamics data. The mathematical framework of the POD is introduced following
the bi-orthogonal approach by Aubry (1991). The mathematical derivation of the
POD is given, wherever possible, in its most general formulation, without bounding
it to the decomposition of a specific quantity. This choice of the author depends
on the variety of POD applications which are included in this dissertation, ranging
from signal processing problems to applications more strictly related with flow physics.
The mathematical framework includes also one of the POD extensions, the Extended
POD (EPOD), which allows to extract modes linearly correlated to the empirical
eigenfunctions of a second quantity.
The first two applications of the empirical eigenfunctions are strictly connected
with the signal treatment in experimental techniques for Fluid Mechanics. In Chapter
3, the empirical eigenfunctions are identified as an optimal basis in which perform a
"low-pass" spectral filter of experimental fluid data, such as velocity fields measured
with Particle Image Velocimetry (PIV). This filtering is extremely beneficial to reduce
the random errors contained in the PIV fields and obtain a more accurate estimate
of derivative quantities (such as, for instance, vorticity), which are more affected by
random errors. In Chapter 4 the POD is exploited for the pre-treatment of a sequence
of PIV images. The aim is to remove background and reflections, which are sources
of uncertainty in PIV measurements. In this case a "high-pass" spectral filtering is
applied to the PIV image ensemble in order to remove the highly-coherent part of the
signal corresponding to the background.
In the third and fourth applications, the POD is applied to recover the underlying
dynamics of a flow. More specifically, in Chapter 5 the POD is applied to the complex
wake of a pair of cylinders in tandem arrangement with the additional perturbation
of the wall proximity. Through this technique it is possible to track the changes in
the oscillatory behaviour of the wake instabilities ascribed to different geometrical
configurations of the cylinders. In Chapter 6 the POD and the EPOD are applied
respectively to the flow fields around an airfoil in plunging and pitching motion and
to the unsteady aerodynamic forces acting on the airfoil. The decomposition allows
to extract a reduced set of modes of the flow field which are related to the force
generation mechanism. These modes correspond to well-recognizable phenomena of
the flow which can be identified for diverse airfoil kinematics. This flow-field driven
force decomposition is analysed on the light of existing force models, enabling their
reinterpretation and driving towards possible corrections.
The final application is devoted to overcome the low temporal resolution of typical
flow field measurements, such as PIV, by proposing a robust estimation of turbulent
flows dynamics. The method employs a modified version of the EPOD to identify the
correlation between a non-time-resolved field measurement and a time-resolved point
measurement. The estimation of the time-resolved flow fields is obtained exploiting
the correlation of the flow fields with the temporal information contained in the point
measurements.El objetivo principal de las descomposiciones modales es obtener un conjunto de
funciones que sean capaces de describir de una manera compacta la variabilidad
contenida en un conjunto de observables/datos. Si bien este objetivo puede ser
fácilmente realizado mediante el uso de las autofunciones del operador del cual los
observables dependen, las autofunciones empíricas permiten obtener un resultado
similar partiendo de un conjunto de datos sin la necesidad de conocer el operador del
problema. En Mecánica de Fluidos y en ciencias relacionadas con esta disciplina, una
de las técnicas más relevantes para obtener autofunciones empíricas es la conocida
como Descomposición Modal Ortogonal (Proper Orthogonal Decomposition, POD).
Esta tesis contiene diversas aplicaciones de las autofunciones empíricas en datos de
Aerodinámica (Experimental). La base matemática de la POD es introducida siguiendo
la aproximación biortogonal realizada por Aubry (1991). La formulación matemática
de la POD es expresada siempre que es posible en el marco más general posible,
sin condicionarla a la descomposición de una variable en concreto. La elección del
autor dependerá de las diferentes aplicaciones de la POD, todas ellas descritas en
la presente tesis, las cuales abarcan desde problemas de procesado de señales hasta
aplicaciones más estrictamente relacionadas con el análisis de la física del flujo. La
formulación matemática incluye también uno de las extensiones de la POD, la POD
Extendida (EPOD), la cual permite extraer modos linealmente correlacionados con las
autofunciones empíricas de una segunda variable. Las dos primeras aplicaciones de las
autofunciones empíricas están estrictamente relacionadas con el tratamiento de señales
en técnicas experimentales de Mecánica de Fluidos. En el Capítulo 3, las autofunciones
empíricas son identificadas como una base optima, la cual se puede utilizar para realizar
un filtro pasa bajos espectral para datos experimentales de flujos, tales como campos
de velocidad obtenidos mediante la técnica de Velocimetría por Imágenes de Partículas,
(Particle Image Velocimetry, PIV). Este tipo de filtro es muy beneficioso para reducir
los errores de carácter aleatorio contenidos en los campos de PIV y por tanto obtener
una estimación más precisa en las cantidades que precisan del uso de derivadas (por
ejemplo, la vorticidad), ya que están más afectadas por este tipo de errores. En el Capítulo 4, la POD es utilizada para el pretratamiento de una secuencia de imágenes
de PIV. El objetivo es reducir el fondo de la imagen y las reflexiones, ambas fuentes
de incertidumbre en las medidas de PIV. En este caso, un filtro pasa altos espectral
es aplicado al conjunto de imágenes de PIV para poder quitar la parte mayormente
correlacionada de la señal, la cual corresponde con el fondo de la imagen. En la tercera
y cuarta aplicación de la POD, está técnica es utilizada para reconstruir las dinámicas
fundamentales de un flujo. Concretamente, en el Capítulo 5 la POD es utilizada para
analizar la estela compleja que se produce en una pareja de cilindros en tándem con la
perturbación adicional de una pared próxima a ellos. A través de esta técnica, es posible
poder estudiar los cambios en el comportamiento oscilatorio de las inestabilidades de
la estela, las cuales están relacionadas con las diferentes configuraciones geométricas
de los cilindros. En el capítulo 6, la POD y la EPOD son aplicadas respectivamente
a campos fluidos y fuerzas aerodinámicas producidos por un perfil aerodinámico en
movimiento (de rotación y desplazamiento vertical) no estacionario. La técnica de
descomposición permite extraer un conjunto reducido de modos del campo fluido que
están relacionados con el mecanismo que genera las fuerzas aerodinámicas. Estos modos
corresponden con fenómenos característicos del flujo que pueden ser identificados para
diferentes cinemáticas de perfiles aerodinámicos. Estas dinámicas del flujo que están
conectadas con las fuerzas aerodinámicas son analizadas teniendo en cuenta los modelos
ya existentes en la literatura que describen las fuerzas aerodinámicas, permitiendo su
reinterpretación e incluso pudiendo añadir posibles correcciones. La última aplicación
propuesta está destinada a subsanar la baja resolución temporal típica de las medidas
de campo fluido, como en aquellas realizadas utilizando PIV, mediante una estimación
robusta de las dinámicas del flujo turbulento. El método propuesto emplea una versión
modificada de la EPOD para identificar para correlación entre un campo fluido medido
que no está resuelto en el tiempo y una medida puntual que sí que está resulta en el
tiempo. La estimación del campo fluido resuelto en el tiempo es obtenida mediante la
correlación de los campos de flujo con la información temporal contenida en la medida
puntual.This work has been partially supported by the Grant TRA2013-41103-P of the
Spanish Ministry of Economy and Competitiveness, which includes FEDER funding,
and by the Grant DPI2016-79401-R, funded by the Spanish State Research Agency
(SRA) and European Regional Development Fund (ERDF).Programa Oficial de Doctorado en Mecánica de FluidosPresidente: Bharathram Ganapathisubramani.- Secretario: Francisco Javier Rodríguez Rodríguez.- Vocal: Francisco J. Huera-Huart
Basketball feint and non-verbal communication: empirical framework
Bodily communication has its own epistemological framework in which the message follows a process of encoding, transmission and decoding. It establishes contacts and relationships that are developed first by data processing and after by message content evaluating. It has, within it, an ethnic-social substrate that changes in different cultures and contexts. It is a dynamic flow consisting of five basic elements: context, sender, recipient, channel, code and follows a logical and analogical process. The arguments of bodily communication affect the feint, which means manifest intention of achieving a goal through the initial implementation of a plan with specific motor signs, postures, attitudes, which are later implemented in totally different pursuance It refers to the “tactics” decoding of bodily communication. In this way, non-verbal communication have to be included both in experimental and human sciences, so it can investigated by observation and data collected and get together the quantitative and qualitative aspects. The game situations in basketball are so many variables, determined from interacting behaviors engines all players, between teammates and against the opponents. The behaviors of the feints are of great importance both that quality execution technique that every player has and to choice the tactical option. In this study, it is request to recognize the main aspects in basketball, such as in volleyball in past study and to give an argumentative and deductive classification. Method is the observation by descriptive research of three experts: coach of team, experts of body communication and performance analyst. Results show some interested aspects. The body feint is always a deliberate attempt to deceive the opponent to gain an advantage in the context of the game, moreover, it is the basis of the game of basketball, along one players against one, on which is built the complex process of acquisition of tactical advantages over opponents. There are some prerequisites to be able to realize the motor actions of fake, definitely a good knowledge of the rules of the game, knowing how to hesitate (take time before changing direction) or anticipate a move (make a cut changing speed) and especially the ability to read situations game tactics. In conclusion, for young athletes, the education of these aspects becomes essential to ensure the development of the imagination and anticipation motor, which imply the ability of invention and adaptation to different situations of the game. The more a player forces the opponent to react to his feint (shooting, passing or departure dribble), instead of acting, the more likely will have to gain the benefits (time and space) in order to carry out his plan motor effectively (to make an easy score). Although, it is to highlight that, in the modern basketball defensive tactics (zone press, help and recovery, doublings, defensive switch, etc.) start to work out the following game situations: the defender must not have more behavior liabilities compared to the attacker, but in turn must perform the behavior of pretending to try to reverse the situation tactic, creating disorientation, or otherwise, creating an unexpected situation for the attacker; in order to create; an advantage for the defense (recovery of the ball on the dribble, on the steps or on the shoot)
Sport skills and mental health
From a study previously published on the occasion of the scientific meeting of the International Conference on Sports Science and Disability held in Naples at the University Naval February 15, 2014, be clear that "It is appropriate to the study of a process for the effective implementation of these activities and connected to an objective evaluation tool”. This work illustrates a practice used for a pilot project currently underway. Analysis of the practices used. Administering tests validated (FPS, POMS, tests Rockfort, measurement bmi) to an experimental group and a control group. They were also used additional assessment instruments calibrated for the specific use. Graphical representation of the data obtained. The analysis of currently available data is positive, this data will be compared with the final data to get a picture more complete. In Conclusions the data collected if confirmed by the end of the pilot project to encourage the creation of an experimental project in which they are involved more patients and more facilities in order to evaluate the results
The Movement and Sport Science in Italy Towards the European Research Council
AbstractEuropean Research Council Executive Agency, (ERCEA), has the mission to encourage the highest quality research in Europe through competitive funding and to support investigator-driven frontier research across all field, on the basis of scientific excellence. In 2019, European Research Council (ERC) updates the Panel Structure in 3 areas: Social Sciences and Humanities SH, Physical Sciences and Engineering PE, Life Sciences LS, 25 panels and 333 sub-panels. Every UE countries are updating own academic body system to align to the ERC. In Italy, this alignment is not possible because Movement and sport science has been together place SH and LS as academic disciplines of Physical training and Sport sciences. This is the vexata quaestio that makes the Italian academic system different from the other EU countries with consequences on the development of Italian research in Europa. Historical review explains why this division exists and why it begun after the second great war and developed to nowadays, determining an atypical model than others European countries. Movement and sport science should to be reasonably placed in an unique scientific area or alignments coherently at the related subpanels according to the scientific evidences, even if they are placed in more ERC areas. Both options can be applied according to ERC thought to resolve the actual problem
Crossing the Border Line: Interpreting Federal Drug Trafficking Statutes in United States v. Londono-Villa
Pectic enzymes as potential enhancers of ascorbic acid production through the D-galacturonate pathway in Solanaceae
The increase of L-Ascorbic Acid (AsA) content in tomato (Solanum lycopersicum) is a common goal in breeding programs due to its beneficial effect on human health. To shed light into the regulation of fruit AsA content, we exploited a Solanum pennellii introgression line (IL12-4-SL) harbouring one quantitative trait locus that increases the content of total AsA in the fruit. Biochemical and transcriptomic analyses were carried out in fruits of IL12-4-SL in comparison with the cultivated line M82 at different stages of ripening. AsA content was studied in relation with pectin methylesterase (PME) activity and the degree of pectin methylesterification (DME). Our results indicated that the increase of AsA content in IL12-4-SL fruits was related with pectin de-methylesterification/degradation. Specific PME, polygalacturonase (PG) and UDP-D-glucuronic-acid-4-epimerase (UGlcAE) isoforms were proposed as components of the D-galacturonate pathway leading to AsA biosynthesis. The relationship between AsA content and PME activity was also exploited in PMEI tobacco plants expressing a specific PME inhibitor (PMEI). Here we report that tobacco PMEI plants, altered in PME activity and degree of pectin methylesterification, showed a reduction in low methylesterified pectic domains and exhibited a reduced AsA content. Overall, our results provide novel biochemical and genetic traits for increasing antioxidant content by marker-assisted selection in the Solanaceae family
Teaching method of physical education and sports by prescriptive or heuristic learning
The didactics traditionally is imparted by the coach/trainer/teacher with tutorials that have the theoretical basis in the Cognitive approach. It means the coach/trainer/teacher illustrates in greater detail by the coach, are of Partial type, Varied, Randomized and Mental Training. It refers to the models of motor control to Open Loop, Closed Loop, and Motor Program Generalized. Teaching Methods of Physical activity is also imparted by another approach called Ecological-Dynamic where the coach does not require the tutorials, but builds a setting learning environment aimed at variety of learning. It refers to the models for the control of the Motor Imagery and Freedom Degrees. The first one could be in first person and in third person; the second one is three consecutive steps: Reduction, Exploration and Capitalization of the degrees of freedom. Aim is to study the issue of motor control theory and its relation to learning process and body knowledge. It carries out specific aspect of learning approach. Main results show two types of correspondence: 1) between cognitive approach and motor control closed loop, open loop and generalized motor program; furthermore, there is a significant correspondence among order, demand, sequence and timing on movement learning: 2) between ecological dynamic approach and motor control Motor Imagery and Freedom Degrees; furthermore, there is a significant correspondence among setting, learning environment and specific strategies of teaching method such as cooperative learning, role playing, circle time, brain storming, peer education, tutorship, focus group. In this way it can see the invasive role of the coach/trainer/teacher in cognitive approach and non-invasive role in ecological dynamic approach
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