Collections in Institutional Herbaria listed as Rhizopogon, but not belonging to this genus

Fifty-five collections misidentified and stored in various institutional herbaria, under severa1 Rhizopogon species narnes, are revised. Among these, twelve belong to Ascomycotina and 9 were identified to species level; the other collections, immature fruitbodies wcre impossible to identify with the data available. Forty-two collections are Basidiomycotina and only an immature Scleroderma remain without identification to the species level.

La gestión de los libros electrónicos en la Biblioteca Virtual de la UOC

El texto que se presenta muestra cómo se lleva a cabo la gestión de los libros electrónicos en la Biblioteca Virtual (en adelante BV) de la Universitat Oberta de Catalunya (en adelante UOC). La BV pone especial énfasis en la adquisición de libros digitales para mejorar el acceso de los usuarios a los recursos y a lascolecciones de una universidad caracterizada por su virtualidad. El documento presenta, en primer lugar, el entorno en el que se adquieren y se utilizan los libros electrónicos: se describen los distintos escenarios de adquisición en los que se puede encontrar la BV y se definen los circuitos internos que permiten su gestión, así como los procesos técnicos de los documentos. A continuación, se muestran las distintas opciones de acceso y consulta de libros electrónicos que actualmente se ofrecen desde la BV y se exponenlos análisis de uso de dichos documentos. Por último, se presentan las conclusiones a las que llega la BV sobre el nuevo contexto de libros electrónicos.

From institutional repositories to personal collections of learning resources

Institutional digital repositories are a basic piece to provide preservation and reutilization of learning resources. However, their creation and maintenance is usually performed following a top-down approach, causing limitations in the search and reutilization of learning resources. In order to avoid this problem we propose to use web 2.0 functionalities. In this paper we present how tagging can be used to enhance the search and reusability functionalities of institutional learning repositories as well as promoting their usage. The paper also describes the evaluation process that was performed in a pilot experience involving open educational resources.

Evaluation of an electronic nose to assess fruit ripeness

The main goal of our study was to see whether an artificial olfactory system can be used as a nondestructive instrument to measure fruit maturity. In order to make an objective comparison, samples measured with our electronic nose prototype were later characterized using fruit quality techniques. The cultivars chosen for the study were peaches, nectarines, apples, and pears. With peaches and nectarines, a PCA analysis on the electronic nose measurements helped to guess optimal harvest dates that were in good agreement with the ones obtained with fruit quality techniques. A good correlation between sensor signals and some fruit quality indicators was also found. With pears, the study addressed the possibility of classifying samples regarding their ripeness state after different cold storage and shelf-life periods. A PCA analysis showed good separation between samples measured after a shelf-life period of seven days and samples with four or less days. Finally, the electronic nose monitored the shelf-life ripening of apples. A good correlation between electronic nose signals and firmness, starch index, and acidity parameters was found. These results prove that electronic noses have the potential of becoming a reliable instrument to assess fruit ripeness.

Bioinspired electronic white cane implementation based on a LIDAR, a tri-axial accelerometer and a tactile belt

This work proposes the creation of a bioinspired electronic white cane for blind people using the whiskers principle for short-range navigation and exploration. Whiskers are coarse hairs of an animal's face that tells the animal that it has touched something using the nerves of the skin. In this work the raw data acquired from a low-size terrestrial LIDAR and a tri-axial accelerometer is converted into tactile information using several electromagnetic devices configured as a tactile belt. The LIDAR and the accelerometer are attached to the user’s forearm and connected with a wire to the control unit placed on the belt. Early validation experiments carried out in the laboratory are promising in terms of usability and description of the environment.

Ultrasonic and LIDAR sensors for electronic canopy characterization in vineyards: advances to improve pesticide application methods

Canopy characterization is a key factor to improve pesticide application methods in tree crops and vineyards. Development of quick, easy and efficient methods to determine the fundamental parameters used to characterize canopy structure is thus an important need. In this research the use of ultrasonic and LIDAR sensors have been compared with the traditional manual and destructive canopy measurement procedure. For both methods the values of key parameters such as crop height, crop width, crop volume or leaf area have been compared. Obtained results indicate that an ultrasonic sensor is an appropriate tool to determine the average canopy characteristics, while a LIDAR sensor provides more accuracy and detailed information about the canopy. Good correlations have been obtained between crop volume (CVU) values measured with ultrasonic sensors and leaf area index, LAI (R2 = 0.51). A good correlation has also been obtained between the canopy volume measured with ultrasonic and LIDAR sensors (R2 = 0.52). Laser measurements of crop height (CHL) allow one to accurately predict the canopy volume. The proposed new technologies seems very appropriate as complementary tools to improve the efficiency of pesticide applications, although further improvements are still needed.

Investigation of defect formation and electronic transport in microcrystalline silicon deposited by hot-wire CVD

We have investigated doped and undoped layers of microcrystalline silicon prepared by hot-wire chemical vapour deposition optically, electrically and by means of transmission electron microscopy. Besides needle-like crystals grown perpendicular to the substrate's surface, all of the layers contained a noncrystalline phase with a volume fraction between 4% and 25%. A high oxygen content of several per cent in the porous phase was detected by electron energy loss spectrometry. Deep-level transient spectroscopy of the crystals suggests that the concentration of electrically active defects is less than 1% of the undoped background concentration of typically 10^17 cm -3. Frequency-dependent measurements of the conductance and capacitance perpendicular to the substrate surface showed that a hopping process takes place within the noncrystalline phase parallel to the conduction in the crystals. The parasitic contribution to the electrical circuit arising from the porous phase is believed to be an important loss mechanism in the output of a pin-structured photovoltaic solar cell deposited by hot-wire CVD.

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.

The Electronic Structure of Co-Sputtered Zinc Indium Tin Oxide Thin Films

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses 50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO2 films.

Electronic properties of a quantum wire with arbitrary bending angle

The electron transmission and bound state properties of a quantum wire with a sharp bend at arbitrary angle are studied, extending results on the right angle sharp bend (the L¿shaped wire). These new results are compared to those of a similar structure, the circular bend wire. The possibility of using a bent wire to perform transistor action is also discussed.

La gestión de libros electrónicos de la Biblioteca Virtual de la Universitat Oberta de Catalunya

La comunicación que se presenta, muestra cómo se lleva a cabo la gestión de los procesos técnicos de los libros electrónicos en la Biblioteca Virtual (en adelante BV) de la Universitat Oberta de Catalunya (en adelante UOC). La BV está integrada en el Campus Virtual y en las aulas virtuales de la Universidad. La principal particularidad de la docencia en la UOC se encuentra en el hecho de que se realiza, en su totalidad, por medio de un Campus Virtual.La BV de la UOC pone especial énfasis en la adquisición de libros digitales para mejorar el acceso de los usuarios a sus recursos y colecciones en una universidad con un modelo de aprendizaje caracterizada por su virtualidad (el 13 de abril de 2011, el Consejo de Gobierno acordó priorizar la adquisición de documentos en formato electrónico). La irrupción de los libros electrónicos en la BV ha comportado una revisión de los procesos técnicos, de manera que los circuitos de adquisición, catalogación y gestión de la colección digital trabajen de forma coordinada. En primer lugar, se describe el entorno en el que se adquieren y se utilizan los libros electrónicos, los distintos escenarios de adquisición y modelos de compra con los que se puede encontrar la BV de la UOC. Se valora el importante papel que desempeña el proveedor en la compra de libros electrónicos. La BV siempre intenta encontrar un equilibrio entre las necesidades de los usuarios, las posibilidades del mercado y los recursos disponibles. Las compras pueden o no ser consorciadas. Cuando se trata de compra consorciada de libros electrónicos se han de sopesar las ventajas e inconvenientes que esta gestión conlleva, tanto económicas cómo de acceso a los contenidos. Cuando un libro está disponible desde distintas plataformas, hay que estudiar cuál es la que se adecúa mejor a las necesidades de la BV. A la hora de decidir el modelo de compra a utilizar hay que considerar diferentes elementos, como la adquisición individual o en paquetes, la compra directa o subscripción, etc. En segundo lugar, se describen los circuitos internos y tratamientos técnicos que experimentan los libros electrónicos. La gestión de estos procesos la llevan a cabo, en mayor o menor medida, los responsables de los servicios de Adquisición, Catalogación y gestión de la Colección Digital, dependiendo de cómo se haya realizado la adquisición (a perpetuidad o subscripción). Por último, se muestran las distintas opciones de acceso que tiene la BV de la UOC a los libros electrónicos, utilizando para ello un sistema de autenticación de usuarios mediante IP (a través de un porxy WAM). Los puntos de acceso a los libros electrónicos son: el catálogo de la BV, el quick set de libros electrónicos de Metalib, el listado A-Z de SFX, la herramienta de descubrimiento Summon y, además, un nuevo acceso desde el nuevo Web de la BV de la UOC. El acceso a los libros electrónicos de la BV de la UOC es una cuestión que aún no está totalmente resuelta. Desde la nueva Web de la BV se está trabajando para conseguir un punto de acceso único. La principal razón por la que no siempre es posible este único punto de acceso es la existencia o inexistencia de las funcionalidades de metabúsqueda en los libros electrónicos que ofrece cada proveedor. A pesar de la complejidad del nuevo contexto del libro electrónico, la BV de la UOC sigue apostando por los nuevos formatos de lectura, que en el 2013 ha representado el 32,30% del fondo bibliográfico y un 45% sobre el presupuesto dedicado para el 2013. Este proceso se realiza trabajando estrechamente con el profesorado, mediante los contenidos disponibles en la ¿Biblioteca en el aula¿ y potenciando la flexibilidad de los gestores y la construcción de nuevos flujos de trabajo que permitan optimizar y facilitar la transición de la lectura de libros tradicionales a la consulta de monografías en formato electrónico.

The Evolution of the European Regulatory Framework for Electronic Communications

The paper reviews the historical transformation of the European regulatory framework for electronic communications from the era dominated by state-owned enterprises to the presence of regulated competition. In the course of these developments, the vision of the roles of the public and private sectors in electronic communications changed in expected and unexpected ways. While the period is characterized by a shift toward less direct state intervention, the intensity of regulation has increased in many areas. Most recently, in the wake of the financial crisis, new forms of state intervention can be observed, including public investment in communications infrastructure and public-private partnerships. As a result of the reforms, Europe has been able to achieve major successes but it also suffered unanticipated setbacks compared to other regions. The European Union emerged as the global leader in mobile communications during the 1990s and was able to roll-out first-generation broadband access networks more rapidly than many of its peers. Recently, however, Europe as a whole has not performed as well in deploying next-generation networks and advanced mobile communications services. The paper offers a political-economic explanation for these developments and assesses their effects on the performance of the European electronic communications sector and the economy. From this analysis, the European model emerges as a unique institutional arrangement with peculiar advantages and disadvantages. Once these are recognized, sensible next steps to build the strengths while avoiding the weaknesses of the model can be seen more clearly.