1,378 research outputs found
Contribution to modeling of soil-plant-atmosphere interactions and coupled hydro-geophysical data assimilation
Full text linkUnderstanding the complex feedback mechanisms regulating the land-atmosphere system has become a scientific imperative, as human induced changes may impact the stability of the Biosphere, both locally and globally. The present thesis work aims at improving current understanding and forecasting capabilities of the Soil-Plant-Atmosphere (SPA) continuum. To this purpose a numerical model of soil moisture dynamics is coupled with plant transpiration and photosynthesis. Soil moisture dynamics is modeled by the 3-D Richards equation and plant uptake is described by an Ohm's law type model accounting for water potential gradients and root, xylem and stomatal conductances. The transpiration flux from soil to the atmosphere is driven by the leaf water potential which is controlled by both local soil moisture conditions and atmospheric forcing. The hydraulic model is linked to the atmosphere by the calculation of the stomatal conductance which is optimized for maximum carbon gain considering Fickian mass transfer of CO2 and H2O through stomata and a biochemical model of photosynthesis. The model is used to investigate competition for water among multiple tree rooting systems in a Loblolly pine (Pinus Taeda) plantation and then coupled with a crop growth module to investigate farmland productivity at the field scale. In order to provide a fully-coupled description of the SPA system, the soil-plant model is then coupled with a slab representation of the Atmospheric Boundary Layer (ABL) and used to investigate the role of water table fluctuations and free atmospheric state on convective rainfall initiation. Model results compared well with measurements of soil moisture, sap flow in the plant xylem as well as energy fluxes above the canopy and convective rainfall initiation time.
In order to deal with the high degree of uncertainty related to both measurement and model errors the applicability of a data assimilation algorithm has also been explored to incorporate physical measurements into the transient hydrological model. Given the recent development of indirect geophysical surveys to monitor soil-plant interactions in the vadose zone, we tested an innovative iterative particle filter approach for coupled hydro-geophysical inversion of Electrical Resistivity Tomography (ERT) data. Model results demonstrate the ability of the method to improve model prediction and estimate multiple model parameters and this work lays the foundation for application of the methodology to soil-plant-atmosphere modeling.La comprensione dei molteplici meccanismi che regolano l'interazione tra suolo, vegetazione e atmosfera è oggi divenuta un imperativo nel campo della ricerca scientifica, poichè numerose sono le conseguenze che la presenza antropica puo avere sulla stabilità della Biosfera, a livello sia globale che locale. Questo lavoro di tesi si propone l'obiettivo di sviluppare nuovi strumenti modellistici che consentano una più accurata comprensione e descrizione del sistema suolo-vegetazione-atmosfera. A tal fine, un modello di trapirazione e fotosintesi della vegetazione è stato introdotto in un codice numerico per la descrizione del flusso in mezzi porosi. La dinamica dell'umidita del suolo e descritta dall'equazione tridimensionale di Richards, mentre il trasporto d'acqua attraverso le radici ed all'interno della pianta e definito tramite un modello di resistenze e potenziali idrici basato sulla legge di Ohm. Il flusso traspirativo è regolato dal potenziale fogliare, a sua volta determinato da condizioni locali di umidità del suolo e dalle forzanti atmosferiche. Il modello idraulico di assorbimento radicale è collegato all'atmosfera tramite il calcolo della resistenza stomatica, determinata sulla base di un modello di ottimizzazione dell'apertura degli stomi che massimizza la fotosintesi (descritta per mezzo di un modello biochimico) e minimizza la traspirazione. Tale approccio modellistico è stato impiegato per comprendere i meccanismi di competizione tra diverse piante per l'assorbimento idrico in una piantagione di Pinus Taeda. Il modello è stato inoltre integrato con un modulo di crescita del mais (Zea mays L.) per studiare la produttività agricola alla scala di bacino. Al fine di descrivere in modo completo le interazioni fra vegetazione ed atmosfera, il modello è stato poi accoppiato con la dinamica dello strato limite planetario ed utilizzato per comprendere l'effetto della falda e delle condizioni dell'atmosfera libera sugli eventi di precipitazione dovuti alla formazione di nubi convettive. I risultati modellistici illustrati in questa tesi sono confrontati con osservazioni di contenuto d'acqua nel suolo, misure di flussi xilematici, flussi energetici al di sopra della canopy ed eventi convettivi di precipitazione, dimostrando le ottime capacità predittive del modello sviluppato.
Sia le osservazioni che i risultati numerici sono tuttavia caratterizzati da un certo grado di errore. Per ovviare a tale incertezza è stato pertanto studiato un algoritmo di assimilazione dei dati che consente di incorporare le osservazioni fisiche nel modello dinamico idrologico. Dal momento che recenti studi di settore si sono focalizzati sull'utilizzo di metodi geofisici indiretti per la caratterizzazione dei processi di interazione fra suolo e vegetazione, in questo lavoro di tesi è stato sviluppato un metodo particle filter iterativo per l'inversione idro-geofisica accoppiata di dati di tomografia elettrica. I risultati presentati in questa tesi dimostrano l'abilità del metodo proposto di migliorare le previsioni e stimare i parametri del modello e pongono le basi per un nuovo approccio alla simulazione numerica del sistema suolo-vegetazione-atmosfera
About twin primes and distribution of primes
Full text linkThis paper give us a demonstration of twin primes conjecture using approximation of function �(iupsilon) that we introduce in section 6. Section 1-5 give us introduction to terminology and a clarification on (iupsilon) terms. In particular section
5 is really important because of its Lemma. Section 7 reassume foregoing explanations and it give us two theorems and one corollary;the theorem 7.2 give us exact approximation of twin primes counting function
Improving Groundwater Modeling by Coupled HydroGeophysical Data Assimilation
No full textA sequential Bayesian approach for joint assimilation of hydrological and geophysical data in a variably saturated flow model is presented.
The study aims to improve simulation results and system understanding by assimilation of multiple type data using a Monte Carlo approach and avoiding the inversion of the geophysical measurements.
A SIR based particle filter data assimilation is implemented in a 3D variably saturated flow model.
Point measurements are directly assimilated in time while spatial information are blended in the simulation by assimilating Electrical Resistivity Tomography (ERT) measurements. To avoid the inversion of the latter, a forward 3D model of electrical current distribution is implemented as the
measurements model in the data assimilation algorithm. The connection with the hydrological parameters occurs via the Archie's law.
A synthetic test case is used to test the assimilation of pressure data, ERT data and the joint assimilation of pressure and ERT data. Performance of the proposed modelling approach are evaluated in terms of predicton efficiency and parameter estimation. Perspectives and limitations of
coupled hydrogeophysical data assimilation are discussed
Audience perceptions of athletes’ brand self-presentation on social media
No full textResearch Question: Current literature on athlete branding on social media is divided into two streams: one explores athletes’ self-presentation strategies and the other investigates how external audiences perceive these brands. However, existing studies lack investigations that simultaneously examine athletes’ content strategies with audiences’ perceptions. Thus, this study aims to answer the following research question: How are female athlete brands’ self-presentation strategies perceived by their online audiences?
Research Methods: We collected 1,903 posts from female athletes playing in the Italian women’s first football division (Serie A), employing the Model of Athlete Branding via Social Media (MABSM) to categorize their self-presentation strategies.
Additionally, we quantified volume-based metrics of consumer engagement on social media (CESM) and analyzed the content of 44,190 comments through top-down and bottom-up automated textual analysis techniques.
Results and Findings: Female athletes are perceived as competing athletes when sharing posts about their sport or personal lives and as social media models when emphasizing their attractive appearance. Notably, some followers tend to perceive athletes in a sexually abusive manner, irrespective of the self-presentation
strategy employed. In contrast to male athletes, content focusing on athletic performance generates a lower volume-based CESM in the female context.
Implications: This research contributes valuable theoretical, methodological, and practical implications to the growing body of literature on athlete branding on social media. Specifically, our study highlights the importance of understanding the nuanced relationship between the types of content shared online by
athlete brands and the resulting audience engagement, both in terms of volume and content
Established and Outsiders at the Same Time - Self-Images and We-Images of Palestinians in the West Bank and in Israel
Full text linkPalestinians frequently present a harmonizing and homogenizing we-image of their own national we-group, as a way of counteracting Israeli attempts to sow divisions among them, whether through Israeli politics or through the dominant public discourse in Israel. However, a closer look reveals the fragility of this homogenizing we-image which masks a variety of internal tensions and conflicts. By applying methods and concepts from biographical research and figurational sociology, the articles in this volume offer an analysis of the Middle East conflict that goes beyond the polar opposition between “Israelis” and “Palestinians”. On the basis of case studies from five urban regions in Palestine and Israel (Bethlehem, Ramallah, East Jerusalem, Haifa and Jaffa), the authors explore the importance of belonging, collective self-images and different forms of social differentiation within Palestinian communities. For each region this is bound up with an analysis of the relevant social and socio-political contexts, and family and life histories. The analysis of (locally) different figurations means focusing on the perspective of Palestinians as members of different religious, socio-economic, political or generational groupings and local group constellations – for instance between Christians and Muslims or between long-time residents and refugees. The following scholars have contributed to this volume: Ahmed Albaba, Johannes Becker, Hendrik Hinrichsen, Gabriele Rosenthal, Nicole Witte, Arne Worm and Rixta Wundrak. Gabriele Rosenthal is a sociologist and professor of Qualitative Methodology at the Center of Methods in Social Sciences, University of Göttingen. Her major research focus is the intergenerational impact of collective and familial history on biographical structures and actional patterns of individuals and family systems. Her current research deals with ethnicity, ethno-political conflicts and the social construction of borders. She is the author and editor of numerous books, including The Holocaust in Three Generations (2009), Interpretative Sozialforschung (2011) and, together with Artur Bogner, Ethnicity, Belonging and Biography (2009)
Gendered Adaptations: Canadian Rewritings of Classical Texts. Author-Translator Conference 2010, University of Swansea, Wales
No full textQuantum many-body scars : realizations and applications
No full textauthor: Gabriele Calliari, BScMasterarbeit Universität Innsbruck 202
The Last Bastion of Architecture
No full textThe essay is a critical interpretation of Rem Koolhaas' theory of Bigness. In fact, of the theories that have best marked the development of architectural culture since World War II – from those of the Smithsons to Rossi, from Eisenman to Venturi and Scott Brown – Rem Koolhaas’s theory of Bigness has probably, more than any other, investigated the intrinsic possibilities of architecture at the end of the 20th century. In light of the number of pseudotheories that have largely characterized the last decade, Bigness is the last constituent fact of recent history: an extremely lucid attempt to draw to a conclusion a history that goes back to the very invention of the modern city, comparing it with architecture’s own immutable core, its physicality, even exposing the theory of Bigness itself to the risk of total failure. The essay investigates the development of the theory of Bigness from its incubation in Koolhaas’s book Delirious New York in 1978, to the "official" presentation in S,M,L,XL in december 1995. The essay presents some parts of the PhD research "L'architettura dei libri. Progetto, scrittura, editoria nella ricerca architettonica contemporanea", developed by the author at Università degli studi G. D'Annunzio, Chieti, Facoltà di Architettura di Pescara, in 2001-2004.
Log 7 Winter/Spring 2006 includes essays of Richard Anderson, Marie J. Aquilino, Amos Gitai, Pier Vittorio Aureli, Manuel Orazi, Jean-Louis Cohen, William Drenttel, Peter Eisenman, Luis Fernandez-Galiano, John Kaliski, Sabir Khan, Reinhold Martin, Gabriele Mastrigli, Deborah Richmond, Julie Rose, Paul Virilio, Eyal Weizman, Mirko Zardini.
Log 7
Winter/Spring 2006
Co-edited by Denise Bratton
Saggi di Richard Anderson, Marie J. Aquilino, Amos Gitai,
Pier Vittorio Aureli, Manuel Orazi, Jean-Louis Cohen, William Drenttel, Peter Eisenman, Luis Fernandez-Galiano, John Kaliski, Sabir Khan, Reinhold Martin, Gabriele Mastrigli, Deborah Richmond, Julie Rose, Paul Virilio, Eyal Weizman, Mirko Zardini
Quantum many-body scars : realizations and applications
No full textauthor: Gabriele Calliari, BScMasterarbeit Universität Innsbruck 202
Quantum many-body scars : realizations and applications
No full textauthor: Gabriele Calliari, BScMasterarbeit Universität Innsbruck 202
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