Conserved developmental expression of Fezf in chordates and Drosophila and the origin of the Zona Limitans Intrathalamica (ZLI) brain organizer

Background: The zona limitans intrathalamica (ZLI) and the isthmus organizer (IsO) are two major secondary organizers of vertebrate brain development. These organizers are located at the interface of the expression domains of key patterning genes (Fezf-Irx and Otx-Gbx, respectively). To gain insights into the evolutionary origin of the ZLI, we studied Fezf in bilaterians. Results: In this paper, we identified a conserved sequence motif (Fezf box) in all bilaterians. We report the expression pattern of Fezf in amphioxus and Drosophila and compare it with those of Gbx, Otx and Irx. We found that the relative expression patterns of these genes in vertebrates are fully conserved in amphioxus and flies, indicating that the genetic subdivisions defining the location of both secondary organizers in early vertebrate brain development were probably present in the last common ancestor of extant bilaterians. However, in contrast to vertebrates, we found that Irx-defective flies do not show an affected Fezf expression pattern. Conclusions: The absence of expression of the corresponding morphogens from cells at these conserved genetic boundaries in invertebrates suggests that the organizing properties might have evolved specifically in the vertebrate lineage by the recruitment of key morphogens to these conserved genetic locations.

Beneficial effects of word final stress in segmenting a new language: evidence from ERPs

Background: How do listeners manage to recognize words in an unfamiliar language? The physical continuity of the signal, in which real silent pauses between words are lacking, makes it a difficult task. However, there are multiple cues that can be exploited to localize word boundaries and to segment the acoustic signal. In the present study, word-stress was manipulated with statistical information and placed in different syllables within trisyllabic nonsense words to explore the result of the combination of the cues in an online word segmentation task. Results: The behavioral results showed that words were segmented better when stress was placed on the final syllables than when it was placed on the middle or first syllable. The electrophysiological results showed an increase in the amplitude of the P2 component, which seemed to be sensitive to word-stress and its location within words. Conclusion: The results demonstrated that listeners can integrate specific prosodic and distributional cues when segmenting speech. An ERP component related to word-stress cues was identified: stressed syllables elicited larger amplitudes in the P2 component than unstressed ones.

Hardness of FRHC-Cu determined by statistical analysis

A statistical indentation method has been employed to study the hardness value of fire-refined high conductivity copper, using nanoindentation technique. The Joslin and Oliver approach was used with the aim to separate the hardness (H) influence of copper matrix, from that of inclusions and grain boundaries. This approach relies on a large array of imprints (around 400 indentations), performed at 150 nm of indentation depth. A statistical study using a cumulative distribution function fit and Gaussian simulated distributions, exhibits that H for each phase can be extracted when the indentation depth is much lower than the size of the secondary phases. It is found that the thermal treatment produces a hardness increase, due to the partly re-dissolution of the inclusions (mainly Pb and Sn) in the matrix.

Defining ecologically relevant water quality targets for lakes in Europe

1. The implementation of the Water Framework Directive requires EU member states to establish and harmonize ecological status class boundaries for biological quality elements. In this paper, we describe an approach for defining ecological class boundaries that delineates shifts in lake ecosystem functioning and, therefore, provides ecologically meaningful targets for water policy in Europe. 2. We collected an extensive data set of 810 lake-years from nine Central European countries, and we used phytoplankton chlorophyll a, a metric widely used to measure the impact of eutrophication in lakes. Our approach establishes chlorophyll a target values in relation to three significant ecological effects of eutrophication: the decline of aquatic macrophytes, the dominance of potentially harmful cyanobacteria and the major functional switch from a clear water to a turbid state. 3. Ranges of threshold chlorophyll a concentrations are given for the two most common lake types in lowland Central Europe: for moderately deep lakes (mean depth 3–15 m), the greatest ecological shifts occur in the range 10–12 lg L 1 chlorophyll a, and for shallow lakes (<3 m mean depth), in the range 21–23 lg L 1 chlorophyll a. 4. Synthesis and applications. Our study provides class boundaries for determining the ecological status of lakes, which have robust ecological consequences for lake functioning and which, therefore, provide strong and objective targets for sustainable water management in Europe. The results have been endorsed by all participant member states and adopted in the European Commission legislation, marking the first attempt in international water policy to move from physico-chemical quality standards to harmonized ecologically based quality targets.

L'ús de les tecnologies audiovisuals com a recurs didàctic en museus d'història i espais de presentació del patrimoni

La presentació del patrimoni en els museus i altres espais afins (exposicions, parcs arqueològics, centres d"interpretació patrimonial, etcètera) s"està beneficiant en els últims anys dels avenços a nivell didàctic que ofereixen les noves tecnologies. Però, sovint es fa palès que aquestes estratègies comunicatives no impliquen necessàriament una òptima assimilació del discurs històric i museogràfic per part del públic. La modernització dels espais patrimonials amb la incorporació d"audiovisuals i sistemes informàtics multimèdia no serveix de gran cosa si es planteja com un mer recurs passiu de delectació o com una concessió a la creixent implantació social de les noves tecnologies. És per això que es fa imprescindible plantejar des d"un punt de vista didàctic i comunicatiu com aquests recursos poden construir i/o enriquir el discurs a l"entorn del patrimoni (històric, arqueològic, artístic, etcètera) per a una museografia veritablement comprensiva i, més enllà dels objectes, educadora en valors.

Current Sheet Regulation of Solar Near-relativistic Electron Injection Histories

We present a sample of three large near-relativistic (>50 keV) electron events observed in 2001 by both the ACE and the Ulysses spacecraft, when Ulysses was at high-northern latitudes (>60◦) and close to 2 AU. Despite the large latitudinal distance between the two spacecraft, electrons injected near the Sun reached both heliospheric locations. All three events were associated with large solar flares, strong decametric type II radio bursts and accompanied by wide (>212◦) and fast (>1400 km s−1) coronal mass ejections (CMEs). We use advanced interplanetary transport simulations and make use of the directional intensities observed in situ by the spacecraft to infer the electron injection profile close to the Sun and the interplanetary transport conditions at both low and high latitudes. For the three selected events, we find similar interplanetary transport conditions at different heliolatitudes for a given event, with values of the mean free path ranging from 0.04 AU to 0.27 AU. We find differences in the injection profiles inferred for each spacecraft. We investigate the role that sector boundaries of the heliospheric current sheet (HCS) have on determining the characteristics of the electron injection profiles. Extended injection profiles, associated with coronal shocks, are found if the magnetic footpoints of the spacecraft lay in the same magnetic sector as the associated flare, while intermittent sparse injection episodes appear when the spacecraft footpoints are in the opposite sector or a wrap in the HCS bounded the CME structure.

On the Hall effect in polycrystalline semiconductors

Some problems involved in the interpretation of Hall‐effect measurements in polycrystalline semiconductors have not been resolved, especially when the contribution of the boundaries is appreciable. Using the Herring theory of transport properties in inhomogeneous semiconductors, we present an alternative interpretation to that previously proposed. This model permits the calculation of the Hall coefficient under general conditions.

Electronic transport in low temperature nanocrystalline silicon thin-film transistors obtained by Hot-Wire CVD

Hydrogenated nanocrystalline silicon (nc-Si:H) obtained by hot-wire chemical vapour deposition (HWCVD) at low substrate temperature (150 °C) has been incorporated as the active layer in bottom-gate thin-film transistors (TFTs). These devices were electrically characterised by measuring in vacuum the output and transfer characteristics for different temperatures. The field-effect mobility showed a thermally activated behaviour which could be attributed to carrier trapping at the band tails, as in hydrogenated amorphous silicon (a-Si:H), and potential barriers for the electronic transport. Trapped charge at the interfaces of the columns, which are typical in nc-Si:H, would account for these barriers. By using the Levinson technique, the quality of the material at the column boundaries could be studied. Finally, these results were interpreted according to the particular microstructure of nc-Si:H.

Progress in front propagation research

We review the progress in the field of front propagation in recent years. We survey many physical, biophysical and cross-disciplinary applications, including reduced-variable models of combustion flames, Reid's paradox of rapid forest range expansions, the European colonization of North America during the 19th century, the Neolithic transition in Europe from 13 000 to 5000 years ago, the description of subsistence boundaries, the formation of cultural boundaries, the spread of genetic mutations, theory and experiments on virus infections, models of cancer tumors, etc. Recent theoretical advances are unified in a single framework, encompassing very diverse systems such as those with biased random walks, distributed delays, sequential reaction and dispersion, cohabitation models, age structure and systems with several interacting species. Directions for future progress are outlined

Current Sheet Regulation of Solar Near-Relativistic Electron Injection Histories

We present a sample of three large near-relativistic (>50 keV) electron events observed in 2001 by both the ACE and the Ulysses spacecraft, when Ulysses was at high-northern latitudes (>60°) and close to 2 AU. Despite the large latitudinal distance between the two spacecraft, electrons injected near the Sun reached both heliospheric locations. All three events were associated with large solar flares, strong decametric type II radio bursts and accompanied by wide (>212°) and fast (>1400 km s-1) coronal mass ejections (CMEs). We use advanced interplanetary transport simulations and make use of the directional intensities observed in situ by the spacecraft to infer the electron injection profile close to the Sun and the interplanetary transport conditions at both low and high latitudes. For the three selected events, we find similar interplanetary transport conditions at different heliolatitudes for a given event, with values of the mean free path ranging from 0.04 AU to 0.27 AU. We find differences in the injection profiles inferred for each spacecraft. We investigate the role that sector boundaries of the heliospheric current sheet (HCS) have on determining the characteristics of the electron injection profiles. Extended injection profiles, associated with coronal shocks, are found if the magnetic footpoints of the spacecraft lay in the same magnetic sector as the associated flare, while intermittent sparse injection episodes appear when the spacecraft footpoints are in the opposite sector or a wrap in the HCS bounded the CME structure.

El desarrollo personal y profesional mediante el aprendizaje reflexivo : una experiencia en el grado de Educación Social

In the last years, an increase of the interest to develop educational practices in higher education, based on the approach of the reflective learning, is observed. Nevertheless, we scarcely find in our context researches or experiences that allow knowing students’ perceptions about this teaching and learning approach. We have developed an experience in the bachelor of Social Education at the University of Girona with the aim to contribute to the personal and professional development of future social educators in their initial training, using reflective learning methodology. In this article we present an evaluation of the experience based on students’ perceptions. They assessed the usefulness they think the module has for their training, the methodology and the activities. This evaluation has been carried out through in-depth interviews to 17 students who participated in the module in 2010-11 academic year. The results show that students assess positively the experience, either its general usefulness or the methodology of reflective learning, although they acknowledge some difficulties to carry out such a process which involves a high degree of introspection and a difficulty to set the boundaries in the narration of personal questions. The study also shows some challenges related on the need, but also the difficulty, to include personal and professional development as a powerful axis in the higher education curriculum, as well as elements linked to reflective learning assessment

Towards automated specifications of scenarios in enhanced learning technology

Recent standardization efforts in e-learning technology have resulted in a number of specifications, however, the automation process that is considered essential in a learning management system (LMS) is a lessexplored one. As learning technology becomes more widespread and more heterogeneous, there is a growing need to specify processes that cross the boundaries of a single LMS or learning resource repository. This article proposes to obtain a specification orientated to automation that takes on board the heterogeneity of systems and formats and provides a language for specifying complex and generic interactions. Having this goal in mind, a technique based on three steps is suggested. The semantic conformance profiles, the business process management (BPM) diagram, and its translation into the business process execution language (BPEL) seem to be suitable for achieving it.

A catalogue of Primitive Scenario-Types : The First Step to the Automation of Learning Scenarios

Peer-reviewed

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

La identidad en disputa. Conflictos alrededor de la construcción de la transexualidad

Como toda categoría identitaria, transexual tiene una definición normativa —en este caso, muy marcada por su origen médico—, hay unos agentes sociales que controlan su uso y existe un conflicto alrededor de los límites que abarca. En este artículo, analizamos cómo el conflicto por la delimitación de esta categoría se articula a nivel individual y colectivo. En base al análisis de entrevistas, grupos de discusión y mensajes en foros de Internet, se ha observado que hay un choque entre dos concepciones de la transexualidad. La primera defiende, desde postulados biologistas, que los criterios para entrar dentro de esta categoría son el cambio corporal y una identificación normativa con el género reivindicado. La segunda propone una interpretación más inclusiva y estratégica de la categoría. El choque entre estas dos concepciones permite entender el trasfondo de este debate aparentemente terminológico e invita a repensar la forma de entender la conexión entre el género y el cuerpo.