7,490 research outputs found
Volatility and stock market direction: a study on emerging markets.
Volatility indices, such VIX, can be used for determining stock market direction. In this paper, we analyze the relationship between changes in the VIX direction and changes in the turning point of S&P 500 and the MSCI Latin-America Emerging Market index, in order to see whether they anticipate the changes. Also, the volatility of emerging markets measured by standard deviation and their relationship with the stock market movements within this market are calculated, since the greater the value of the volatility, the greater the likelihood of a rise or fall. In order to locate the turning point and the upward and downward phases of the cycles, empirical methods are applied and are characterized by using a set of decision rules that reflect the practical experience gained by analysts. Our conclusions include: Turning points, or peaks and troughs, in the VIX are coincident with peaks and troughs in the opposite direction for the S&P 500 index and in emerging markets
Tensor and tensor-isospin terms in the effective Gogny interaction
We discuss the need of including tensor terms in the effective Gogny
interaction used in mean-field calculations. We show in one illustrative case
that, with the usual tensor term that is employed in the Skyrme interaction
(and that allows us to separate the like-nucleon and the neutron-proton tensor
contributions), we can describe the evolution of the N=28 neutron gap in
calcium isotopes. We propose to include a tensor and a tensor-isospin term in
finite-range interactions of Gogny type. The parameters of the two tensor terms
allow us to treat separately the like-nucleon and the neutron-proton
contributions. Two parameterizations of the tensor terms have been chosen to
reproduce different neutron single-particle properties in the 48Ca nucleus and
the energy of the first 0- state in the 16O nucleus. By employing these two
parameterizations we analyze the evolution of the N=14, 28, and 90 neutron
energy gaps in oxygen, calcium and tin isotopes, respectively. We show that the
combination of the parameters governing the like-nucleon contribution is
crucial to correctly reproduce the experimental (where available) or
shell-model trends for the evolution of the three neutron gaps under study.Comment: 20 pages, 6 figures. Accepted for publication in Physical Review
L’autonomia scolastica e le politiche di valutazione degli insegnanti nei paesi europei
Recent years have seen intensified awareness about teachers’ role in promoting student learning and, consequently, an increased emphasis on evaluating teachers and their work. Among many school factors, the teaching quality is a key-parameter of student learning. For these reasons, in many national contexts teacher performance evaluation is one of the elements that draw significantattention, in terms of both international surveys and concrete measures.Starting from the state of the art in several European school systems, our goal is to describe, compare and analyse models adopted to assess teaching quality. We attempt to highlight any differences in perspectives and models agreed by the European systems and to reflect on risks and opportunities, strengths and weaknesses associated with the use of such instruments in the teacher evaluation. The teachers are only one of many factors that influence student achievements, but the evaluation of teachers is necessary because there is an increased awareness of how crucial the teachers are in the achievement of students and in the progress of society.Negli ultimi anni si è intensificata la consapevolezza sul ruolo degli insegnanti nel promuovere l’apprendimento degli studenti e, di conseguenza, sono aumentate le indagini sulla valutazione degli insegnanti e sul loro lavoro. Tra i molti fattori scolastici, la qualità dell’insegnamento è un parametro chiaveper lo sviluppo degli apprendimenti degli studenti. Per questi motivi, il tema della valutazione della performance degli insegnanti costituisce uno degli elementi su cui si è maggiormente concentrata l’attenzione sia sul piano delle indagini internazionali che delle concrete misure messe a punto all’internodei diversi contesti nazionali. L’articolo nasce da queste premesse. Partendo dallo stato dell’arte nei diversi sistemi scolastici europei, il nostro obiettivo è quello di analizzare i modelli utilizzati per valutare la qualità dell’insegnamento al fine di mettere in evidenza i punti di forza, i nodi critici e le problematicità
Stock Market Crisis in Spain and their Comparison with Other International Market: Analysis of the Principal Characteristics
Periódicamente en los mercados bursátiles se producen periodos de caídas drásticas que
son denominados como “crisis bursátiles”. El análisis de estas crisis sobre el mercado bursátil
Español y sus repercusiones, puede permitir a gestores e inversores anticipar sus estrategias
ante las mismas. Las variables empíricas más importantes que definen a una crisis, las cuales
serán objeto de este estudio, son el porcentaje de caída desde el máximo, la duración de
la caída y el tiempo necesario hasta recuperar el máximo anterior. La comparación de estas
variables con las obtenidas del análisis de los mercados Americano, Alemán e Inglés, nos
permitirá ver el grado de correlación entre crisis a nivel internacional y realizar previsiones.Regularly there are periods of a dramatic decline in stock markets that are defined as “stock
market crashes” and cause “stock market crisis”. Analysis of the influence of this crisis over
the Spanish stock market and their repercussions can enable stockbrokers and investor to use
anticipating strategies. The most outstanding empirical variables which define a crisis, which are
the object of this study, are the maximum drawndown percentage, de duration of the decline and
the recovery time. The comparison of these variables with those obtained from the American,
German and English markets analysis allows us to see the degree of correlation between these
crises and to do forecasting
Effective tensor forces and neutron rich nuclei
We study the effects of the tensor term of the effective nucleon-nucleon
interaction on nuclear excited states. Our investigation has been conducted by
using a self-consistent Random Phase Approximation approach. We investigate
various nuclei in different regions of the isotopes chart. Results for a set of
calcium isotopes are shown.Comment: 4 pages, 4 figures, 1 table Proc. 10th International Spring Seminar
on Nuclear Physics New Quests in Nuclear Structure, Vietri Sul Mare, May
21-25, 201
Dolphin Morbillivirus in Eurasian Otters, Italy
We report biomolecular evidence of dolphin morbillivirus in 4 wild Eurasian otters (Lutra lutra) from southern Italy; 2 animals showed simultaneous immunohistochemical reactivity against morbilliviral antigen. These cases add further concern and support to the progressively expanding host range of dolphin morbillivirus in the western Mediterranean Sea
English on the Screen: Using Audiovisual Resources in the Communicative Classroom
Proyecto en el que se defiende el potencial de los medios audiovisuales como recurso para enseñar el inglés como lengua extranjera, más concretamente un largometraje en versión original, el cual será el punto de partida para un proyecto cooperativo en grupos
Enhanced Industrial Machinery Condition Monitoring Methodology based on Novelty Detection and Multi-Modal Analysis
This paper presents a condition-based monitoring methodology based on novelty detection applied to industrial machinery. The proposed approach includes both, the classical classification of multiple a priori known scenarios, and the innovative detection capability of new operating modes not previously available. The development of condition-based monitoring methodologies considering the isolation capabilities of unexpected scenarios represents, nowadays, a trending topic able to answer the demanding requirements of the future industrial processes monitoring systems. First, the method is based on the temporal segmentation of the available physical magnitudes, and the estimation of a set of time-based statistical features. Then, a double feature reduction stage based on Principal Component Analysis and Linear Discriminant Analysis is applied in order to optimize the classification and novelty detection performances. The posterior combination of a Feed-forward Neural Network and One-Class Support Vector Machine allows the proper interpretation of known and unknown operating conditions. The effectiveness of this novel condition monitoring scheme has been verified by experimental results obtained from an automotive industry machine.Postprint (published version
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