El cambio estratégico en la adquisición del conocimiento: la metodología microgenética

El desarrollo de estrategias cognitivas durante la infancia no es un proceso lineal en el que éstas emergen de manera progresiva sin vaivenes ni retrocesos, sino que de acuerdo con numerosos estudios empíricos (Kuhn, 1995, 2002; Siegler, 1996, 2002) el proceso mediante el cual las estrategias cognitivas emergen y se van consolidando es muy irregular. Consistiría en una secuencia de progresiones y regresiones difícil de captar mediante metodologías estáticas como los diseños clásicos transversales y longitudinales. La perspectiva microgenética aporta una mirada dinámica al proceso de desarrollo y cambio cognitivo. Esta perspectiva utiliza una metodología de recogida de datos de manera intensiva y continuada que permite examinar el cambio mientras éste tiene lugar con el fin de proponer los mecanismos subyacentes al mismo. En el presente trabajo se discuten dos estudios de caso microgenéticos relativos al cambio en las estrategias de adquisición de conocimiento.

Deep radio images of the HEGRA and Whipple TeV sources in the Cygnus OB2 region.

The modern generation of Cherenkov telescopes has revealed a new population of gamma-ray sources in the Galaxy. Some of them have been identified with previously known X-ray binary systems while other remain without clear counterparts a lower energies. Our initial goal here was reporting on extensive radio observations of the first extended and yet unidentified source, namely TeV J2032+4130. This object was originally detected by the HEGRA telescope in the direction of the Cygnus OB2 region and its nature has been a matter of debate during the latest years. The situation has become more complex with the Whipple and MILAGRO telescopes new TeV detections in the same field which could be consistent with the historic HEGRA source, although a different origin cannot be ruled out. Aims.We aim to pursue our radio exploration of the TeV J2032+4130 position that we initiated in a previous paper but taking now into account the latest results from new Whipple and MILAGRO TeV telescopes. The data presented here are an extended follow up of our previous work. Methods.Our investigation is mostly based on interferometric radio observations with the Giant Metre Wave Radio Telescope (GMRT) close to Pune (India) and the Very Large Array (VLA) in New Mexico (USA). We also conducted near infrared observations with the 3.5 m telescope and the OMEGA2000 camera at the Centro Astronómico Hispano Alemán (CAHA) in Almería (Spain). Results.We present deep radio maps centered on the TeV J2032+4130 position at different wavelengths. In particular, our 49 and 20 cm maps cover a field of view larger than half a degree that fully includes the Whipple position and the peak of MILAGRO emission. Our most important result here is a catalogue of 153 radio sources detected at 49 cm within the GMRT antennae primary beam with a full width half maximum (FWHM) of 43 arc-minute. Among them, peculiar sources inside the Whipple error ellipse are discussed in detail, including a likely double-double radio galaxy and a one-sided jet source of possible blazar nature. This last object adds another alternative counterpart possibility to be considered for both the HEGRA, Whipple and MILAGRO emission. Moreover, our multi-configuration VLA images reveal the non-thermal extended emission previously reported by us with improved angular resolution. Its non-thermal spectral index is also confirmed thanks to matching beam observations at the 20 and 6 cm wavelengths.

Discovery of a High-Energy Gamma-Ray-Emitting Persistent Microquasar

Microquasars are stellar x-ray binaries that behave as a scaled down version of extragalactic quasars. The star LS 5039 is a new microquasar system with apparent persistent ejection of relativistic plasma at a 3 kiloparsec distance from the sun. It may also be associated with a gamma-ray source discovered by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the COMPTON-Gamma Ray Observatory satellite. Before the discovery of LS 5039, merely a handful of microquasars had been identified in the Galaxy, and none of them was detected in high-energy gamma-rays.

Deep GMRT radio observations and a multi-wavelength study of the region around HESS J1858+020

Context. There are a number of very high energy sources in the Galaxy that remain unidentified. Multi-wavelength and variability studies, and catalogue searches, are powerful tools to identify the physical counterpart, given the uncertainty in the source location and extension. Aims. This work carries out a thorough multi-wavelength study of the unidentified, very high energy source HESS J1858+020 and its environs. Methods. We have performed Giant Metrewave Radio Telescope observations at 610 MHz and 1.4 GHz to obtain a deep, low-frequency radio image of the region surrounding HESS J1858+020. We analysed archival radio, infrared, and X-ray data as well. This observational information, combined with molecular data, catalogue sources, and a nearby Fermi gamma-ray detection of unidentified origin, are combined to explore possible counterparts to the very high energy source. Results. We provide with a deep radio image of a supernova remnant that might be related to the GeV and TeV emission in the region. We confirm the presence of an H ii region next to the supernova remnant and coincident with molecular emission. A potential region of star formation is also identified. We identify several radio and X-ray sources in the surroundings. Some of these sources are known planetary nebulae, whereas others may be non-thermal extended emitters and embedded young stellar objects. Three old, background Galactic pulsars also neighbour HESS J1858+020 along the line of sight. Conclusions. The region surrounding HESS J1858+020 is rich in molecular structures and non-thermal objects that may potentially be linked to this unidentified very high energy source. In particular, a supernova remnant interacting with nearby molecular clouds may be a good candidate, but a star forming region, or a non-thermal radio source of yet unclear nature, may also be behind the gamma-ray source. The neighbouring pulsars, despite being old and distant, cannot be discarded as candidates. Further observational studies are needed, however, to narrow the search for a counterpart to the HESS source.

Optical spectroscopy of microquasar candidates at low Galactic latitudes

We report optical spectroscopic observations of a sample of 6 low-galactic latitude microquasar candidates selected by cross-identification of X-ray and radio point source catalogs for |b|<5 degrees. Two objects resulted to be of clear extragalactic origin, as an obvious cosmologic redshift has been measured from their emission lines. For the rest, none exhibits a clear stellar-like spectrum as would be expected for genuine Galactic microquasars. Their featureless spectra are consistent with being extragalactic in origin although two of them could be also highly reddened stars. The apparent non-confirmation of our candidates suggests that the population of persistent microquasar systems in the Galaxy is more rare than previously believed. If none of them is galactic, the upper limit to the space density of new Cygnus X-3-like microquasars within 15 kpc would be 1.1\times10^{-12} per cubic pc. A similar upper limit for new LS 5039-like systems within 4 kpc is estimated to be 5.6\times10^{-11} per cubic pc.

EVN+MERLIN observations of microquasar candidates at low galactic latitudes

In an attempt to increase the number of known microquasars, Paredes et al. (2002) have presented a long-term project focused on the search for new objects of this type. They performed a cross-identification between X-ray and radio catalogs under very restrictive selection criteria for sources with |b|<5 degrees, and obtained a sample of 13 radio-emitting X-ray sources. Follow-up observations of 6 of these sources with the VLA provided accurate coordinates, which were used to discover optical counterparts for all of them. We have observed these six sources with the EVN and MERLIN at 5 GHz. Five of the six objects have been detected and imaged, presenting different morphologies: one source has a two-sided jet, three sources have one-sided jets, and one source is compact. With all the presently available information, we conclude that two of the sources are promising microquasar candidates in our Galaxy.

High mass microquasars and low latitude gamma-ray sources

Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a strong concentration toward the inner spiral arms of the Galaxy. Variability, spectral and correlation analysis indicate that this population is not homogeneous. In particular, there is a subgroup of sources that display clear variability in their gamma-ray fluxes on timescales from days to months. Following the proposal by Kaufman Bernad\'o et al. (2002), we suggest that this group of sources might be high-mass microquasars, i.e. accreting black holes or neutron stars with relativistic jets and early-type stellar companions. We present detailed inhomogeneous models for the gamma-ray emission of these systems that include both external and synchrotron self-Compton interactions. We have included effects of interactions between the jet and all external photon fields to which it is exposed: companion star, accretion disk, and hot corona. We make broadband calculations to predict the spectral energy distribution of these objects from radio up to GeV energies. The results and predictions can be tested by present and future gamma-ray instruments like INTEGRAL, AGILE, and GLAST.

Microquasar models for 3EG J1828+0142 and 3EG J1735-1500

Microquasars are promising candidates to emit high-energy gamma-rays. Moreover, statistical studies show that variable EGRET sources at low galactic latitudes could be associated with the inner spiral arms. The variable nature and the location in the Galaxy of the high-mass microquasars, concentrated in the galactic plane and within 55 degrees from the galactic center, give to these objects the status of likely counterparts of the variable low-latitude EGRET sources. We consider in this work the two most variable EGRET sources at low-latitudes: 3EG J1828+0142 and 3EG J1735-1500, proposing a microquasar model to explain the EGRET data in consistency with the observations at lower energies (from radio frequencies to soft gamma-rays) within the EGRET error box.

La llibertat condicional a Catalunya

La recerca analitza quines són les claus actuals de l’ús dela LCa Catalunya. Per fer-ho, primer de tot explica quina és la realitat de les polítiques criminals i d’execució penal practicades a Catalunya i a Espanya i les compara amb altres realitats europees. Els resultats d’aquesta primera part fonamenten la conveniència de fer augmentar de manera significativa la seva aplicació i com aquest augment repercutiria positivament en la millora de les taxes de reincidència, en el desistiment del delicte i en la reinserció social de les persones encarcerades. En la segona part de l’estudi s’analitza el perfil de les persones que arriben a la LC però també de les que no hi arriben, tot i complir algunes de les condicions objectives per fer-ho. De l’estudi d’aquests perfils s’analitzen les similituds i diferències en les característiques dels penats i es fan propostes de millora en la classificació de grau penitenciari i la possibilitat de progressió sense que augmenti el risc teòric de reincidència ni el de recursos a assignar, tot i que sí resulti necessari pensar i fer-ne una redistribució dels actualment existents. La tercera part de l’estudi es dedica a analitzar els obstacles que té l’Administració per poder fer propostes de millora per augmentar la seva implementació. Entre les dificultats analitzades es comenten: el model d’aplicació espanyol sobre la LC, la satisfacció de la responsabilitat civil, els estrangers que es troben en situació administrativa irregular a Espanya, els retards en la concessió dels permisos ordinaris i les progressions de grau i el seguiment i control de la LC. L’estudi ha fet servir metodologies quantitatives i qualitatives simultàniament. La informació obtinguda es triangula i s’assenyalen aquells punts on el consens és més global i aquells punts més controvertits on els resultats no permeten extreure’n conclusions fefaents. En la part quantitativa s’han analitzat utilitzant diferents tècniques estadístiques 3.340 casos que es trobaven l’any 2012 en LC, 3r grau i 2n grau. En la part qualitativa, s’ha fet anàlisi de casos, entrevistes en profunditat, grups focals, tècnica Delphi i recull bibliogràfic i de legislació comparada. La recerca acaba proposant 23 propostes de millora agrupades en 6 blocs d’intervenció.

La libertad condicional en Cataluña

La investigación analiza cuáles son las claves actuales del uso de la libertad condicional (LC) en Cataluña. Para hacerlo, primero explica cuáles son las realidades de las políticas criminales y de ejecución penal practicadas en Cataluña y España y las compara con otras realidades europeas. Los resultados de esta primera parte fundamentan la conveniencia de aumentar de manera significativa su aplicación y cómo este aumento repercutiría positivamente en la mejora de las tasas de reincidencia, en el desistimiento del delito y en la reinserción social de las personas encarceladas. En la segunda parte del estudio se analiza el perfil de las personas que llegan a LC, pero también de las que no llegan, a pesar de cumplir algunas de las condiciones objetivas para hacerlo. Del estudio de estos perfiles se analizan las similitudes y diferencias en las características de los penados y se hacen propuestas de mejora en la clasificación de grado penitenciario y la posibilidad de progresión sin que aumente el riesgo teórico de reincidencia ni el de recursos a asignar, aunque sí hacer una redistribución de los actualmente existentes. La tercera parte del estudio analiza los obstáculos que tiene la Administración para poder hacer propuestas de mejora para aumentar la aplicación de la LC. Entre las dificultades analizadas se comentan: el modelo de aplicación español sobre la LC, la satisfacción de la responsabilidad civil, los extranjeros que se encuentran en situación administrativa irregular en España, los retrasos en la concesión de los permisos ordinarios y las progresiones de grado y el seguimiento y control de la LC. El estudio ha utilizado metodologías cuantitativas y cualitativas simultáneamente. La información obtenida se triangula y se señalan aquellos puntos donde el consenso es más global y aquellos puntos más controvertidos donde los resultados no permiten extraer conclusiones fehacientes. En la parte cuantitativa se han analizado 3.340 casos que se encontraban en 2012 en LC, 3 º grado y 2 º grado utilizando diferentes técnicas estadísticas. En la parte cualitativa, se han hecho análisis de casos, entrevistas en profundidad, grupos focales, técnica Delphi y recopilación bibliográfica y de legislación comparada. La investigación termina proponiendo 23 propuestas de mejora agrupadas en 6 bloques de intervención.

Biopolítica de Estados expulsores

La biopolítica sobre los migrantes se fundamenta en el binomio dejar entrar-residir o expulsar. Las leyes de extranjería están elaboradas sobre dos ejes: por un lado, en la regulación de los lujos migratorios en función del mercado de trabajo y las demandas de la economía y, por otro, en el control policial y la persecución de la inmigración irregular. Para la realización del primer eje del binomio, dejar entrar y residir, los Estados se dotan de mecanismos de regulación e intervención sobre el inmigrante concebido como fuerza de trabajo productiva. Asimismo los Estados crean mecanismos de control-sanción para las personas migrantes que incumplen los requisitos establecidos para entrar y residir en el territorio. En este punto la biopolítica sobrela población migrante se solapa o toma forma en el ejercicio de la soberanía por el Leviatán. Las medidas de control y sanción que los gobiernos ponen en marcha sobre los sin papeles han creado una imponente maquinaria de coacción en el interior de las instituciones del Estado de derecho hasta el punto de convertirlo en un Estado expulsor.

Estados expulsores y semipersonas en la Unión Europea

La aprobación en junio de 2008 por el Parlamento Europeo de la Directiva de retorno denominada también Directiva de la infamia o Directiva de expulsión consolida el proceso de involución que sobre los derechos humanos se viene produciendo en la Unión Europea desde que el miedo a la inmigración irregular se incardinó en sus instituciones. Si bien las legislaciones de extranjería de los años ochenta contenían normas que regulaban el internamiento y la expulsión no es hasta la Directiva 2001/40/CE que comienza a tomar forma una política comunitaria centrada en la inmigración irregular y las expulsiones de migrantes. Las medidas de retorno son, dice la Comisión europea,"una piedra angular de la política de migración de la UE". Desde entonces, la barbarie de los centros de retención e internamiento, el socavamiento de los derechos y la exclusión y criminalización de los migrantes extranjeros se han convertido en el caballo de batalla de las asociaciones defensoras de los derechos humanos. La erosión que las legislaciones y medidas de expulsión están provocado en los derechos y libertades y en las instituciones del Estado de derecho es inmensa. El retroceso y la erosión en los derechos y libertades es tan grande que ya no es posible continuar hablando sin más de Estados de derecho en la UE, sino más bien de máquinas administrativas para el internamiento y la expulsión, de"Estados expulsores"(1), donde las personas extranjeras son tratadas como semipersonas (2) e incluso como"no-personas" (3).

Microcalcification evaluation in computer assisted diagnosis for digital mammography

In order to develop applications for z;isual interpretation of medical images, the early detection and evaluation of microcalcifications in digital mammograms is verg important since their presence is oftenassociated with a high incidence of breast cancers. Accurate classification into benign and malignant groups would help improve diagnostic sensitivity as well as reduce the number of unnecessa y biopsies. The challenge here is the selection of the useful features to distinguish benign from malignant micro calcifications. Our purpose in this work is to analyse a microcalcification evaluation method based on a set of shapebased features extracted from the digitised mammography. The segmentation of the microcalcificationsis performed using a fixed-tolerance region growing method to extract boundaries of calcifications with manually selected seed pixels. Taking into account that shapes and sizes of clustered microcalcificationshave been associated with a high risk of carcinoma based on digerent subjective measures, such as whether or not the calcifications are irregular, linear, vermiform, branched, rounded or ring like, our efforts were addressed to obtain a feature set related to the shape. The identification of the pammeters concerning the malignant character of the microcalcifications was performed on a set of 146 mammograms with their real diagnosis known in advance from biopsies. This allowed identifying the following shape-based parameters as the relevant ones: Number of clusters, Number of holes, Area, Feret elongation, Roughness, and Elongation. Further experiments on a set of 70 new mammogmms showed that the performance of the classification scheme is close to the mean performance of three expert radiologists, which allows to consider the proposed method for assisting the diagnosis and encourages to continue the investigation in the senseof adding new features not only related to the shape

Stable sampling and Fourier multipliers

We study the relationship between stable sampling sequences for bandlimited functions in $L^p(\R^n)$ and the Fourier multipliers in $L^p$. In the case that the sequence is a lattice and the spectrum is a fundamental domain for the lattice the connection is complete. In the case of irregular sequences there is still a partial relationship.

Further insights in trichothiodistrophy: a clinical, microscopic, and ultrastructural study of 20 cases and literature review

Background: Trichothiodistrophy (TTD) is a rare autosomal recessive condition that is characterized by a specific congenital hair shaft dysplasia caused by deficiency of sulfur associated with a wide spectrum of multisystem abnormalities. In this article, we study clinical, microscopic, and ultrastructural findings of 20 patients with TTD with the aim to add further insights regarding to this rare condition. Additionally, analyses of our results are compared with those extracted from the literature in order to enhance its comprehensibility. Materials and Methods: Twenty cases of TTD were included: 7 from Mexico and 14 from Spain. Clinical, microscopic, scanning electron microscopy (SEM) studies and X-ray microanalysis (XrMa) were carried out in all of them. Genetic studies were performed in all seven Mexican cases. Patients with xeroderma pigmentosum and xeroderma pigmentosum/TTD-complex were excluded. Results: Cuticular changes and longitudinal crests of the hair shaft were demonstrated. These crests were irregular, disorganized, following the hair longest axis. Hair shaft sulfur deficiency was disposed discontinuously and intermittently rather than uniformly. This severe decrease of sulfur contents was located close to the trichoschisis areas. Only five patients did not show related disturbances. Micro-dolichocephaly was observed in five cases and represented the most frequent facial dysmorphism found. It is also remarkable that all patients with urologic malformations also combined diverse neurologic disorders. Moreover, three Mexican sisters demonstrated the coexistence of scarce pubic vellus hair, developmental delay, onychodystrophy, and maxillar/mandibullar hypoplasia. Conclusions: TTD phenotype has greatly varied from very subtle forms to severe alterations such as neurologic abnormalities, blindness, lamellar ichthyosis and gonadal malformations. Herein, a multisystem study should be performed mandatorily in patients diagnosed with TTD.