Clay pot irrigation for tomato (Lycopersicon esculentum Mill) production in the north east semiarid region of Ethiopia

Water shortage is one of the major constraints for production of horticultural crops in arid and semiarid regions. A field experiment was conducted to determine irrigation water and fertilizer use efficiency, growth and yield of tomato under clay pot irrigation at the experimental site of Sekota Dryland Agricultural Research Center, Lalibela, Ethiopia in 2009/10. The experiment comprised of five treatments including furrow irrigated control and clay pot irrigation with different plant population and fertilization methods, which were arranged in Randomized Complete Block Design with three replications. The highest total and marketable fruit yields were obtained from clay pot irrigation combined with application of nitrogen fertilizer with irrigation water irrespective of difference in plant population. The clay pot irrigation had seasonal water use of up to 143.71 mm, which resulted in significantly higher water use efficiency (33.62 kg m^-3) as compared to the furrow irrigation, which had a seasonal water use of 485.50 mm, and a water use efficiency of 6.67 kg m^-3. Application of nitrogen fertilizer with irrigation water in clay pots improved fertilizer use efficiency of tomato by up to 52% than band application with furrow or clay pot irrigation. Thus, clay pot irrigation with 33,333 plants ha^-1 and nitrogen fertilizer application with irrigation water in clay pots was the best method for increasing the yield of tomato while economizing the use of water and nitrogen fertilizer in a semiarid environment.

Large-Size AlGaN/GaN HEMT Large-Signal Electrothermal Characterization and Modeling for Wireless Digital Communications

The rapid growth in high data rate communication systems has introduced new high spectral efficient modulation techniques and standards such as LTE-A (long term evolution-advanced) for 4G (4th generation) systems. These techniques have provided a broader bandwidth but introduced high peak-to-average power ratio (PAR) problem at the high power amplifier (HPA) level of the communication system base transceiver station (BTS). To avoid spectral spreading due to high PAR, stringent requirement on linearity is needed which brings the HPA to operate at large back-off power at the expense of power efficiency. Consequently, high power devices are fundamental in HPAs for high linearity and efficiency. Recent development in wide bandgap power devices, in particular AlGaN/GaN HEMT, has offered higher power level with superior linearity-efficiency trade-off in microwaves communication. For cost-effective HPA design to production cycle, rigorous computer aided design (CAD) AlGaN/GaN HEMT models are essential to reflect real response with increasing power level and channel temperature. Therefore, large-size AlGaN/GaN HEMT large-signal electrothermal modeling procedure is proposed. The HEMT structure analysis, characterization, data processing, model extraction and model implementation phases have been covered in this thesis including trapping and self-heating dispersion accounting for nonlinear drain current collapse. The small-signal model is extracted using the 22-element modeling procedure developed in our department. The intrinsic large-signal model is deeply investigated in conjunction with linearity prediction. The accuracy of the nonlinear drain current has been enhanced through several issues such as trapping and self-heating characterization. Also, the HEMT structure thermal profile has been investigated and corresponding thermal resistance has been extracted through thermal simulation and chuck-controlled temperature pulsed I(V) and static DC measurements. Higher-order equivalent thermal model is extracted and implemented in the HEMT large-signal model to accurately estimate instantaneous channel temperature. Moreover, trapping and self-heating transients has been characterized through transient measurements. The obtained time constants are represented by equivalent sub-circuits and integrated in the nonlinear drain current implementation to account for complex communication signals dynamic prediction. The obtained verification of this table-based large-size large-signal electrothermal model implementation has illustrated high accuracy in terms of output power, gain, efficiency and nonlinearity prediction with respect to standard large-signal test signals.

Grain size analyses in tin-lead glazes based on 2d-sections

A problem in the archaeometric classification of Catalan Renaissance pottery is the fact, that the clay supply of the pottery workshops was centrally organized by guilds, and therefore usually all potters of a single production centre produced chemically similar ceramics. However, analysing the glazes of the ware usually a large number of inclusions in the glaze is found, which reveal technological differences between single workshops. These inclusions have been used by the potters in order to opacify the transparent glaze and to achieve a white background for further decoration. In order to distinguish different technological preparation procedures of the single workshops, at a Scanning Electron Microscope the chemical composition of those inclusions as well as their size in the two-dimensional cut is recorded. Based on the latter, a frequency distribution of the apparent diameters is estimated for each sample and type of inclusion. Following an approach by S.D. Wicksell (1925), it is principally possible to transform the distributions of the apparent 2D-diameters back to those of the true three-dimensional bodies. The applicability of this approach and its practical problems are examined using different ways of kernel density estimation and Monte-Carlo tests of the methodology. Finally, it is tested in how far the obtained frequency distributions can be used to classify the pottery

Interactions between grain size and composition of sediments: two examples

Two contrasting case studies of sediment and detrital mineral composition are investigated in order to outline interactions between chemical composition and grain size. Modern glacial sediments exhibit a strong dependence of the two parameters due to the preferential enrichment of mafic minerals, especially biotite, in the fine-grained fractions. On the other hand, the composition of detrital heavy minerals (here: rutile) appears to be not systematically related to grain-size, but is strongly controlled by location, i.e. the petrology of the source rocks of detrital grains. This supports the use of rutile as a well-suited tracer mineral for provenance studies. The results further suggest that (i) interpretations derived from whole-rock sediment geochemistry should be flanked by grain-size observations, and (ii) a more sound statistical evaluation of these interactions require the development of new tailor-made statistical tools to deal with such so-called two-way compositions

A Log-linear model of grain size influence on the geochemistry of sediments

Sediment composition is mainly controlled by the nature of the source rock(s), and chemical (weathering) and physical processes (mechanical crushing, abrasion, hydrodynamic sorting) during alteration and transport. Although the factors controlling these processes are conceptually well understood, detailed quantification of compositional changes induced by a single process are rare, as are examples where the effects of several processes can be distinguished. The present study was designed to characterize the role of mechanical crushing and sorting in the absence of chemical weathering. Twenty sediment samples were taken from Alpine glaciers that erode almost pure granitoid lithologies. For each sample, 11 grain-size fractions from granules to clay (ø grades <-1 to >9) were separated, and each fraction was analysed for its chemical composition. The presence of clear steps in the box-plots of all parts (in adequate ilr and clr scales) against ø is assumed to be explained by typical crystal size ranges for the relevant mineral phases. These scatter plots and the biplot suggest a splitting of the full grain size range into three groups: coarser than ø=4 (comparatively rich in SiO2, Na2O, K2O, Al2O3, and dominated by “felsic” minerals like quartz and feldspar), finer than ø=8 (comparatively rich in TiO2, MnO, MgO, Fe2O3, mostly related to “mafic” sheet silicates like biotite and chlorite), and intermediate grains sizes (4≤ø <8; comparatively rich in P2O5 and CaO, related to apatite, some feldspar). To further test the absence of chemical weathering, the observed compositions were regressed against three explanatory variables: a trend on grain size in ø scale, a step function for ø≥4, and another for ø≥8. The original hypothesis was that the trend could be identified with weathering effects, whereas each step function would highlight those minerals with biggest characteristic size at its lower end. Results suggest that this assumption is reasonable for the step function, but that besides weathering some other factors (different mechanical behavior of minerals) have also an important contribution to the trend. Key words: sediment, geochemistry, grain size, regression, step function

Statistical treatment of grain-size curves and empirical distributions: densities as compositions?

The preceding two editions of CoDaWork included talks on the possible consideration of densities as infinite compositions: Egozcue and D´ıaz-Barrero (2003) extended the Euclidean structure of the simplex to a Hilbert space structure of the set of densities within a bounded interval, and van den Boogaart (2005) generalized this to the set of densities bounded by an arbitrary reference density. From the many variations of the Hilbert structures available, we work with three cases. For bounded variables, a basis derived from Legendre polynomials is used. For variables with a lower bound, we standardize them with respect to an exponential distribution and express their densities as coordinates in a basis derived from Laguerre polynomials. Finally, for unbounded variables, a normal distribution is used as reference, and coordinates are obtained with respect to a Hermite-polynomials-based basis. To get the coordinates, several approaches can be considered. A numerical accuracy problem occurs if one estimates the coordinates directly by using discretized scalar products. Thus we propose to use a weighted linear regression approach, where all k- order polynomials are used as predictand variables and weights are proportional to the reference density. Finally, for the case of 2-order Hermite polinomials (normal reference) and 1-order Laguerre polinomials (exponential), one can also derive the coordinates from their relationships to the classical mean and variance. Apart of these theoretical issues, this contribution focuses on the application of this theory to two main problems in sedimentary geology: the comparison of several grain size distributions, and the comparison among different rocks of the empirical distribution of a property measured on a batch of individual grains from the same rock or sediment, like their composition

El Treball en equip: com es pot desenvolupar la competència al llarg del pla d'estudis

En aquest article s’exposen els resultats del projecte desenvolupat a l’Escola Politècnica Superior de Castelldefels per incorporar les quatre competències recollides en el seu pla d’estudis: treball en equip, comunicació eficaç, aprenentatge autònom i treball per projectes. El projecte desenvolupa les quatre competències de manera coordinada amb els programes de les assignatures dels plans d’estudi. En aquest document s’exposen els resultats d’aplicar un pla d’activitats dissenyat per desenvolupar la capacitat de treballar en equip entre els estudiants de primer curs de les titulacions de Telemàtica, Telecomunicacions i Aeronàutica. Mitjançant qüestionaris i informes, els estudiants mostren quina és la seva percepció sobre els punts forts i els febles. També reflexionen sobre els aspectes que s’han de millorar del seu propi grup. El projecte inclou un sistema de recollida de dades que permet analitzar les respostes dels estudiants. Els resultats de l’experiència mostren una evolució positiva en l’actitud i en la percepció que els estudiants tenen respecte a la competència de treball en grup. En els apartats següents es presenta la valoració de l’experiència centrada en una de les possibles línies d’investigació

De com la literatura pot ser útil a la geografia. Reflexions arran de la lectura d'un llibre

Reflexió sobre com la literatura pot servir de suport als estudiosos de la geografia humanística. L’autor comenta diversos exemples literaris per a il•lustrar-ho i arriba a la conclusió que l’anàlisi fenomenològica de la literatura obre al geògraf un camp d’infinites possibilitats

El control de la pot??ncia en la preparaci?? d'un grup d'escaladors de competici??

Resumen tomado del autor

El mestre immers dins l´escola d´avui, poc se pot recordar de Barbiana. 'El maestro inmerso dentro de la escuela de hoy, poco puede acordarse de Barbiana'.

Resumen tomado de la publicación

¿Pot interessar Costa i Llobera a l'alumnat del segle XXI?. '¿Puede interesarle Costa i Llobera al alumnado del siglo XXI?'.

Incluido en el número dedicado a los escritores Joan Alcover, Miquel Costa i Llobera y Pere Capellà

How do I set up my thesis so it meets the University's Page Setup regulations for paper size and margins?

This video shows how to ensure the document: • has mirror margins that alternate on left and right hand pages • is A4 in size • has margins that are in-line with the regulations • has its major sections starting on the right hand (odd numbered) page Although this video shows how to perform these tasks in Word 2010, they are virtually identical in Word 2013. In Word 2011 for Mac the steps are very similar and precise details can be found in the Word 2011 Sections manual.

La escuela y la familia en la Kampuchea democrática: análisis de las transformaciones promovidas por Pol Pot, a la luz de la teoría marxista

La presente monografía tiene por interés estudiar el caso de violencia masiva vivida en Camboya bajo el mando de los Jemeres Rojos. De manera particular, pretende analizar las drásticas transformaciones promovidas por Pol Pot sobre las instituciones de la escuela y la familia; transformaciones que derivaron en una grave desintegración social cuyo significado histórico resulta inexpresable. Teniendo en cuenta el contexto político, social y económico que condujo al régimen de la Kampuchea Democrática, se hace uso del marxismo como enfoque teórico para analizar lo sucedido en Camboya. Partiendo del concepto de estructura social, se profundiza en la teoría a través de sus planteamientos básicos, para así llegar a la comprensión del papel y la importancia que juegan en ella las instituciones de la familia y la escuela en tanto que Aparatos Ideológicos de Estado. Este ejercicio permite identificar las principales distorsiones entre la teoría, apelada por Pol Pot, y las prácticas de los Jemeres Rojos en Camboya.

La participació dels infants pot ser una realitat : manual per a la participació. 'La participación de los niños puede ser una realidad : manual para la participación'.

Este manual pretende ser un instrumento para los profesionales de la educación, de la dinamización y de la enseñanza, y para los agentes sociales, y el primer paso para un cambio en la concepción de los niños y adolescencia. Son agentes activos, capaces de descubrir problemas sociales y familiares, y con capacidad para presentar propuestas y soluciones. En primer lugar se define lo que es la participación social, en segundo lugar se plantean las bases pedagógicas de la participación, en tercer lugar se abordan las habilidades necesarias (comunicación y liderazgo), seguidamente se comenta el papel del adulto como dinamizador del proceso participativo, y a continuación se aborda con detenimiento el grupo, sus características, condiciones, etapas y roles. Más adelante se comentan los aspectos a evaluar y las consecuencias de la participación. El material se completa con referencias bibliográficas.

The Intrapreneur Innovation:Led by Medium and Small Size Companies‘Managers*(Qualitative Research)

This research is focused on an exploratory study developed with Pymes managers and theirroles as intrapreneurs. Using their leadership to impel innovation into organizations.Looking to determined how Pymes employers incentive into organizations individuals or groupinnovations. Therefore, it is possible to think that managers lead the innovation process, whichis classified gradually according to companies needs in order to improve their competitiveness.Organization must have intrapreneuring and organized culture with flexible structure to generateindividual autonomy. A characteristic is the amount of capital risk needed; that is why it isnecessary encourage their work and their risk tolerance.