Download or read book The role of physical and biological soil crusts on the water balance in semiarid ecosystems written by Sonia Chamizo de la Piedra and published by Universidad Almería. This book was released on 2014-11-06 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: In arid and semiarid areas, the interplant spaces are usually covered by physical and biological soil crusts. These crusts, though representing an almost negligible portion of the soil profile, have a number of crucial roles. Soil crusts form the boundary between soil and atmosphere and therefore control gas, water and nutrient exchange into and through soils. Concretely, in the last decade, the study of biological soil crusts (BSCs) (complex communities of cyanobacteria, algae, fungi, lichens, mosses and other microorganisms in intimate association with soil particles) has drawn the attention of a growing number of researchers due to the key role they play in numerous processes in the ecosystems where they appear. Unlike physical crusts, BSCs protect soils against erosion by water and wind, and increase soil fertility by fixing atmospheric C and N, synthesising polysaccharides and reducing nutrient losses by runoff and erosion. Through their influence on numerous properties that affect how water moves though soils such as roughness, porosity, hydrophobicity, cracking, and albedo, BSCs play a key role in water processes, such as infiltration and runoff, evaporation and soil moisture. It is widely known the role of physical crusts in decreasing soil porosity and hydraulic conductivity, thus decreasing infiltration. However, there is controversy regarding the role of BSCs in infiltration and runoff processes. Some studies indicate that BSCs increase infiltration, and consequently, decrease runoff, whereas others have reported that they decrease infiltration and increase runoff or that they have no effect on either of them. In addition, the influence of BSCs on other soil water balance components such as evaporation and soil moisture has hardly been studied and the scarce existing studies also show contradicting results. With the aim of enlightening the role that BSCs play in the water balance in semiarid areas, in this thesis it has been analysed the influence of different soil crust types, physical crusts and various developmental stages of BSCs, on key soil water balance components such as infiltration-runoff, evaporation and soil moisture, at plot scale. Furthermore, to better understand how these crusts affect hydrological processes, the influence of the type of crust and developmental stage of the crust on different properties that affect water movement and retention in soils has been analysed. Last, spectral characteristics of the different crust types, as well as of vegetation, have been examined with the aim of developing a spectral classification system for differentiation of these common ground covers in semiarid areas that allows their mapping and the modelling of the effects of the crusted areas on hydrological and erosion processes on larger spatial scales (hillslope and catchment). To conduct this research, two areas where BSCs are widespread and that represent key spatial distributions of BSCs in semiarid ecosystems were chosen in the province of Almeria (SE Spain): El Cautivo (in the Tabernas Desert), a badlands catchment with silty-loam textured soils, and Las Amoladeras (in the Cabo de Gata-Níjar Natural Park), a flat area with sandy-loam textured soils. Our results show that BSCs increase aggregate stability, water retention capacity, and organic carbon and total nitrogen content compared to physical crusts and, within BSCs, these properties increase in the crust and the underlying soil as the crust is more developed (in terms of greater biomass and later-successional species composition). The increase in soil properties with the presence of BSCs is especially noticeable in the top layer of soil (0.01 m) and decreases with depth (0.01-0.05 m) (Chapter I). Through their effect increasing surface roughness and physico-chemical soil properties, BSCs increase infiltration and decrease runoff compared to physical crusts. In general, infiltration increases with greater BSC development (Chapter II). However, there are exceptions to this general pattern that are conditioned by other factors such as the spatial scale under study or the type of rainfall. At small plot sizes (0.25 m2) and after 1h-high intensity simulated rainfall (50 mmh-1), we found that well-developed BSCs such as lichens, generate higher runoff rates than less developed BSCs as cyanobacteria, and similar runoff rates to physical crusts (Chapter II). Thus, at microplot scales and under extreme events, the effect of well-developed BSCs in enhancing infiltration due to their greater roughness can be overcome by their ability to clog soil pores when wet, thus increasing runoff. However, when the influence of BSCs on infiltration and runoff is analysed under natural rain events and at larger spatial scales (1-10 m2), we found that, in low intensity rainfalls, runoff decreases with the cover of well-developed BSCs (lichens) and this effect is higher as the plot size increases (Chapter III). Such decrease in runoff with the presence of well-developed BSCs is due to the microtopography that these crusts confer to soils. Under high intensity rainfalls, BSC cover has no significant effect on runoff yield and the main factor acting to determine runoff generation is rainfall intensity (Chapter III). The removal of the crust initially causes infiltration to increase. But this effect diminishes over time as raindrop impact reseals the surface and a new physical crust is formed that increases runoff (Chapter II). Moreover, crust disturbance by trampling but, especially by removal, causes a dramatic increase in erosion (Chapter II). Erosion also depends on the type of BSC. Well-developed crusts as lichens and mosses generate lower erosion rates than less developed crusts as cyanobacteria. Regarding the influence of BSCs on soil evaporation, under saturation conditions and warm ambient temperatures, soil water loss is quick in all types of surfaces and no significant differences are found in soils with or without BSCs (Chapter V). However, during long cold wet periods, soil water loss is faster in soils devoid of BSCs than in those covered by them. Thus, BSC-crusted soils maintain more soil moisture at the upper soil layer (0.03 m) than adjacent soils where the BSC has been removed, during wet periods. At deeper soil (0.10 m), soil moisture is similar in both BSC-crusted and uncrusted soils. The removal of the BSC causes a higher decrease in soil moisture in fine-textured soils (Cautivo), where the presence of BSCs has a stronger influence on increasing porosity and infiltration, than in coarse-textured soils (Las Amoladeras). During dry soil periods, soil moisture is similar in soils with or without BSCs (Chapter V). Last, a quantitative analysis of spectral characteristics of vegetation, physical crusts and BSC developmental stages has demonstrated the possibility of classifying these common ground covers in semiarid areas based on distinctive spectral features (Chapter VI). The application of the classification system developed to multi and hiperspectral provides the possibility for future mapping of spatial distribution and temporal dynamics of BSCs, which is crucial to incorporating the effects of crusted surfaces in current hydrological and erosion models. Summarizing, compared to physical crusts, the presence of BSCs increase physico-chemical properties of underlying soils, especially in the first centimeters of soil, and this enhancement is greater as the BSC is more developed. Due to this increase in soil properties and the higher roughness that BSCs provide to soils, BSCs increase water input by increasing infiltration and soil moisture, and soil moisture, and reduce water output by reducing soil evaporation. Hence, compared to physical crusts, the presence of BSCs and, especially the presence of well-developed BSCs, have an overall positive effect on the local water balance in semiarid ecosystems, in addition to having a major role in protecting soils from erosion.

Download or read book Procesos creativos en investigaci n cualitativa I written by Eugenia Trigo and published by Lulu.com. This book was released on 2013-09-04 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: La investigación es preguntar y saber lo que pregunto... no es esperar respuestas, sino adquirir conocimiento. Este libro surge de la necesidad de presentar a docentes y estudiantes de Maestrías y Doctorados, ejemplos de lineamientos básicos investigativos de enfoque cualitativo. Considerando que la investigación es creación, propuesta, desafío, nunca la verdad, se muestran cuatro tesis doctorales realizadas en los últimos años en tres países y contextos académicos distintos. Hay elementos que se repiten en cada tesis -son los fundamentos de la investigación cualitativa que, de una u otra manera, deben estar presentes en todo el enfoque. Y, al mismo tiempo, hay diferencias en la manera como cada autor abordó su proyecto. Ahí está la riqueza de este trabajo.

Download or read book Microencapsulaci n de nanopart culas de quitosano para la administraci n pulmonar de macromol culas terap uticas written by and published by Univ Santiago de Compostela. This book was released on with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book La formaci n doctoral en Am rica Latina m s de lo mismo una cuesti n pendiente written by Eugenia Trigo and published by Lulu.com. This book was released on 2014-01-04 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: La actitud competitiva e individualista de la "sociedad capitalista del conocimiento" ha generado y sigue generando una carrera loca en la apertura de programas doctorales en Colombia y América Latina. Estos programas, en su generalidad, están ofreciendo más de lo mismo en el sentido de repetir los modelos extranjeros con una visión colonialista de mantener el status quo. Consideramos que el libro "La formación doctoral en América Latina... ¿más de lo mismo?, ¿una cuestión pendiente?" aspira a desvelar los entresijos de esta formación y proponer otras visiones que intentan ofrecer respuestas posibles a los numerosos interrogantes que nos planteamos para la región. Invitamos a los lectores a participar del desafío.

Download or read book EUI Review written by and published by . This book was released on 2007 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amazonia written by James M. Cooper and published by Apollo Books. This book was released on 2013 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: A title that sets out how the Amazon Basin's indigenous self-determination meets corporate profiteering, where the future of natural resource stewardship is hotly debated, where subsistence living, extreme poverty, and the vagaries of the international commodities markets are revealed.

Download or read book European Kiss Beso Europeo written by Leanen Menorti and published by Palibrio. This book was released on 2019-11-11 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fiorella Smargiassi loves stories and has many suitors; and she will only love the man who can conquer her with a story. Antolini Calizzo writes letters to the love of his life, and the letters tell the following story: “A French painter teaches his younger brother to make a woman fall in love, without knowing that she is the woman he loves in silence.” The book is written in two languages. (English & Spanish) Fiorella Smargiassi ama las historias y tiene muchos pretendientes; y ella únicamente amará al hombre que pueda conquistarla con una historia. Antolini Calizzo escribe cartas al amor de su vida, y las cartas cuentan la siguiente historia: “Un pintor francés enseña a su hermano menor a enamorar a una mujer, sin saber que ella es la mujer que él ama en silencio”. El libro está escrito en dos idiomas. (Inglés & Español)

Download or read book Aqu All Y Acull written by Vincent A. Serpa and published by . This book was released on 1988-04-19 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: A textbook for intermediate students learning Spanish.

Download or read book Arte y oficio del director teatral en Am rica Latina written by Gustavo Geirola and published by Lulu.com. This book was released on 2012 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: The art and practice of directing in Latin America: Central America and United States. Part of a series of interviews with directors from Latin America.

Download or read book Anuario written by Universidad Nacional Autónoma de México. Escuela de Graduados and published by . This book was released on 1949 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Policy Analysis in Argentina written by Nelson Cardozo and published by Policy Press. This book was released on 2023-07-20 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest edition in the International Library of Policy Analysis series explores a comprehensive overview of policy analysis in Argentina. It explores theoretical frameworks, views of the State, the development of the field, and current paradigms before examining knowledge produced at different levels (federal, provincial, and local); the application of the discipline by 'Internal Policy Advisory Councils, Consultants, and Committees'; the role of think tanks, NGOs, and political parties; and the developments provided by university teaching and research. Analysing the conceptual frameworks and methodologies used from a meta-theoretical perspective, it provides a panoramic picture of the perspectives and challenges of policy analysis in Argentina.

Download or read book One dimensional few photon scattering numerical and analytical techniques written by Sánchez Burillo, Eduardo and published by Prensas de la Universidad de Zaragoza. This book was released on 2017-12-19 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hemos estudiado "scattering" de fotones en guías de onda en 1D interaccionado con átomos mediante MPS. Hemos encontrado un comportamiento no trivial en la emisión espontánea de un átomo acoplado a una guía. Se ha determinado la estructura de la matriz S. Hemos encontrado que los sistemas lineales no inducen correlaciones y caracterizado la emergencia de fotónica lineal. Usando distintas configuraciones de fotones y átomos, hemos visto "scattering" Raman perfecto, generación de 2 fotones perfecta, ausencia de las correlaciones fotón-fotón y hemos propuesto una puerta cuántica.

Download or read book Biblica Vol 71 written by and published by St. Martin's Press. This book was released on with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Procesos creativos en investigaci n cualitativa II written by EUGENIA TRIGO and published by Lulu.com. This book was released on 2013-09-04 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: La investigación es preguntar y saber lo que pregunto... no es esperar respuestas, sino adquirir conocimiento. Este libro surge de la necesidad de presentar a docentes y estudiantes de Maestrías y Doctorados, ejemplos de lineamientos básicos investigativos de enfoque cualitativo. Considerando que la investigación es creación, propuesta, desafío, nunca la verdad, se muestran cuatro tesis doctorales realizadas en los últimos años en tres países y contextos académicos distintos. Hay elementos que se repiten en cada tesis -son los fundamentos de la investigación cualitativa que, de una u otra manera, deben estar presentes en todo el enfoque. Y, al mismo tiempo, hay diferencias en la manera como cada autor abordó su proyecto. Ahí está la riqueza de este trabajo.

Download or read book Research Methods and Methodologies in Education written by James Arthur and published by SAGE. This book was released on 2012-03-19 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'This work will be of immense value to those who are undertaking a significant post-graduate research study in Education. The array of impressive contributors writes in an accessible and clear manner, and brings the attention of the reader to both technical and conceptual terms. This book certainly will be an addition to my own reference library' - Susan Groundwater-Smith, Faculty of Education and Social Work, University of Sydney This straightforward and jargon-free book will provide students with the theoretical understandings, practical knowledge and skills they need to carry out independent research. The international contributors identify key research methodologies, data collection tools and analysis methods, and focus on the direct comparisons between them. Each chapter sets out the strengths and weaknesses of a key research method by: identifying specific research designs presenting a series of relevant data collection tools highlighting which analytical methods which can be used. The chapters cover the full range of methods and methodologies, including internet research, mixed methods research and the various modes of ethnographic research. Additional online materials are also available including links to useful journal articles enabling further reading and exploration of each chapter. This is a key book for M-level students and other postgraduates within Education and Educational Research Methods courses. James Arthur is Head of School and Professor of Education and Civic Engagement at the University of Birmingham, UK. Michael J. Waring is a Senior Lecturer in the School of Sport, Exercise and Human Sciences at Loughborough University, UK. Robert Coe is Professor in the School of Education and Director of the Centre for Evaluation and Monitoring (CEM), Durham University, UK. Larry V. Hedges (PhD) is Board of Trustees Professor of Statistics and Social Policy, at the Institute for Policy Research, Northwestern University, US.

Download or read book Very high energy Gamma ray Observations of Pulsar Wind Nebulae and Cataclysmic Variable Stars with MAGIC and Development of Trigger Systems for IACTs written by Rubén López Coto and published by Springer. This book was released on 2016-09-29 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is a comprehensive work that addresses many of the open questions currently being discusssed in the very-high-energy (VHE) gamma-ray community. It presents a detailed description of the MAGIC telescope together with a glimpse of the future Cherenkov Telescope Array (CTA). One section is devoted to the design, development and characterization of trigger systems for current and future imaging atmospheric Cherenkov telescopes. The book also features a state-of-the-art description of pulsar wind nebula (PWN) systems, the study of the multi-TeV spectrum of the Crab nebula, as well as the discovery of VHE gamma rays at the multiwavelength PWN 3C 58, which were sought at these wavelengths for more than twenty years. It also includes the contextualization of this discovery amongst the current population of VHE gamma-ray PWNe. Cataclysmic variable stars represent a new source of gamma ray energies, and are also addressed here. In closing, the thesis reports on the systematic search for VHE gamma-ray emissions of AE Aquarii in a multiwavelength context and the search for VHE gamma-ray variability of novae during outbursts at different wavelengths.

Download or read book Enciclopedia de Ling stica Hisp nica written by Javier Gutiérrez-Rexach and published by Routledge. This book was released on 2016-01-29 with total page 2157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Enciclopedia de Linguistica Hispánica provides comprehensive coverage of the major and subsidiary fields of Spanish linguistics. Entries are extensively cross-referenced and arranged alphabetically within three main sections: Part 1 covers linguistic disciplines, approaches and methodologies. Part 2 brings together the grammar of Spanish, including subsections on phonology, morphology, syntax and semantics. Part 3 brings together the historical, social and geographical factors in the evolution of Spanish. Drawing on the expertise of a wide range of contributors from across the Spanish-speaking world the Enciclopedia de Linguistica Hispánica is an indispensable reference for undergraduate and postgraduate students of Spanish, and for anyone with an academic or professional interest in the Spanish language/Spanish linguistics.