Partition functions and elliptic genera from supergravity

We develop the spacetime aspects of the computation of partition functions for string/M-theory on AdS(3) xM. Subleading corrections to the semi-classical result are included systematically, laying the groundwork for comparison with CFT partition functions via the AdS(3)/CFT(2) correspondence. This leads to a better understanding of the "Farey tail" expansion of Dijkgraaf et. al. from the point of view of bulk physics. Besides clarifying various issues, we also extend the analysis to the N=2 setting with higher derivative effects included.Comment: 34 page

Digital holography using a photographic camera

In this work an experimental device for surface deformation assessment on components and structures is presented. The system is based in a holographic interferometric technique and benefits from all the advantages associated with these techniques such as: high resolution, full field, non contact and the possibility of post processing the obtained numerical data. To perform measurements the proposed device uses digital holograms recorded with a standard digital photographic camera. In order to test and validate the system proposed some experimental results are presented and discussed

Counting Dyons in N=8 String Theory

A recently discovered relation between 4D and 5D black holes is used to derive exact (weighted) BPS black hole degeneracies for 4D N=8 string theory from the exactly known 5D degeneracies. A direct 4D microscopic derivation in terms of weighted 4D D-brane bound state degeneracies is sketched and found to agree.Comment: 10 page

Proposal of a lightweight, offline, full-text search engine for an mHealth app

A patients ability to recall and retrieve health information contributes to a better health management. HealthTalks was developed to address these issues by recording a summary of a medical appointment, uttered by the physician, and transcribing it. For each appointment, the user can also take free-text notes. Nowadays, search engines have become a ubiquitous part of everyones life and are expected on most applications. Here, we describe the development of a search engine for HealthTalks. The apps characteristics demand a lightweight and offline engine, which requires a specific solution rather than an existing library or service. Our approach combines SQLites Full-Text Search 4 module, which includes n-gram indexing, with traditional information retrieval techniques to rank the documents. We created a test collection with summaries of clinical appointments (our documents), information needs, search queries, and relevance assessments for an initial search engine evaluation. Using this test collection, we assessed performance using NDCG@10, the first rank position of a totally relevant result, and query latency. Results are promising, with an average NDCG of 0.97. The median rank position of the first relevant result varies between 1.9 and 1.95, depending on the use of 4-gram character tokenization, an aspect that did not significantly affect the results. We expect this work to be useful for future developments of full-text search engines in mobile environments

How Does a Fundamental String Stretch its Horizon?

It has recently been shown that if we take into account a class of higher derivative corrections to the effective action of heterotic string theory, the entropy of the black hole solution representing elementary string states correctly reproduces the statistical entropy computed from the degeneracy of elementary string states. So far the form of the solution has been analyzed at distance scales large and small compared to the string scale. We analyze the solution that interpolates between these two limits and point out a subtlety in constructing such a solution due to the presence of higher derivative terms in the effective action. We also study the T-duality transformation rules to relate the moduli fields of the effective field theory to the physical compactification radius in the presence of higher derivative corrections and use these results to find the physical radius of compactification near the horizon of the black hole. The radius approaches a finite value even though the corresponding modulus field vanishes. Finally we discuss the non-leading contribution to the black hole entropy due to space-time quantum corrections to the effective action and the ambiguity involved in comparing this result to the statistical entropy.Comment: LaTeX file, 38 pages; v2: minor changes and added reference

Propagação das ondas de flexão em placas compósitas

Este trabalho tem como objectivo principal o estudo experimental/numérico da propagação de ondas de flexão em estruturas laminadas tipo placa. A medição do campo de deslocamentos é efectuada por holografia TV de duplo impulso. Para o efeito foi desenvolvida uma montagem experimental utilizando um LASER de Rubi e um sistema de controlo para, com elevada precisão, gerar e registar no tempo a evolução da força de impacto. Vários registos foram efectuados para diferentes instantes de tempo em duas placas laminadas compósitas. Um programa de elementos finitos, Ansys ®, foi utilizado para, nas mesmas condições de carga e de tempo, simular numericamente a resposta das placas. Por fim, é apresentado o estudo comparativo dos resultados obtidos pelas diferentes técnicas.Os autores agradecem à Fundação para a Ciência e a Tecnologia –FCT o apoio financeiro no âmbito do projecto POCI/EME/63236/2004

Dynamics of soil and canopy temperature: a conceptual approach for Alentejo vineyards

Context and purpose of the study - Climate change imposes increasing restrictions and risks to Mediterranean viticulture. Extreme heat and drought stress events are becoming more frequent which puts in risk sustainability of Mediterranean viticulture. Moreover row crops e.g. grapevine for wine, are increasingly prone to the impact of more intense/longer exposure time to heat stress. The amplified effects of soil surface energy reflectance and conductance on soil-atmosphere heat fluxes can be harmful for leaf and berry physiology. Leaf/canopy temperature is a biophysical variable with both physiological and agronomic meaning. Improved comprehension of spatial and temporal dynamics of soil and leaf/canopy temperature (thermal microclimate) in irrigated vineyards can support improved crop and soil monitoring and management under more extreme and erratic climate conditions. In this work we propose a conceptual approach to integrate information on major soil-vine-atmosphere interactions under deficit irrigation. Ultimately a conceptual model based on temperature relations is proposed to support assessment of the impact of air and soil temperatures on canopy and berry temperatures, leaf senescence and gas exchange. This model may support Decision Support Systems (DSS) for canopy and soil management and irrigation scheduling in Mediterranean vineyards. In addition a set of temperatures (e.g. canopy, soil) are proposed to feed the conceptual models to support the DSSinfo:eu-repo/semantics/publishedVersio

Using soil and canopy temperature to support efficient management of irrigated vineyards

Extreme heat and drought events are becoming more frequent and erratic in Mediterranean Europe. Better comprehension of spatial and temporal dynamics of heat fluxes and thermal microclimate in vineyards can support vineyard’s management and minimize the impact of climate variability. Field experiments were carried out in South Portugal with two red cvs. Touriga Nacional and Aragonez (syn. Tempranillo) under deficit irrigation. Canopy temperature (Tc) is a robust predictor of plant water status, especially when measured under more stressful conditions. In parallel, soil temperature (TS) had a positive influence on TC especially at the cluster zoneinfo:eu-repo/semantics/publishedVersio

Canopy and soil thermal patterns to support management of irrigated vineyards

Irrigated viticulture expanded fast in Southern European countries such as Portugal to optimize berry yield and quality and to increase vine’s longevity. However, intensive irrigation increases pressure over the local and regional water resources, that are getting scarcer, and increases also management costs. Additionally, row crops such as grapevine, are more vulnerable to heat stress due to the additional effects of soil heat fluxes which can negatively influence canopy and berry thermal condition. Therefore, a better understanding of grapevine responses (diurnal and seasonal) to environmental factors (air temperature, soil water) and agronomic practices (deficit irrigation, soil management) are on demand by the industry. Ground based thermography was used to monitor the vertical profile of canopy temperature as well as soil temperature patterns along the day and season as means to assess plant water status and predict risks of heat stress damage. As part of the EU-INNOVINE project, field trials were carried in 2013, 2014 and 2015 in Alentejo (South Portugal). We examined the diurnal and seasonal response of two V. vinifera varieties Aragonez (syn. Tempranillo) and Touriga Nacional subjected to sustained deficit irrigation (SDI), and regulated deficit irrigation (RDI, about 50% of the SDI). Diurnal canopy (TC), and soil surface (Tsoil) temperatures were assessed by thermography. Punctual measurements of leaf temperature with thermal couples, leaf water potential and leaf gas exchange were also done. TC values were above the optimal temperature for leaf photosynthesis during part of the day light period (11:00-14:00h to 17:00h), especially under stressful atmospheric conditions (high VPD, high Tair) and under regulated deficit irrigation. Tsoil was on average about 10-15°C higher than TC. We found strong correlation between TC (derived from thermography) and major physiological traits (leaf water potential and leaf gas exchange). Our results suggest that Tc can be explored as a simple but robust non-intrusive thermal indicator of grapevine performance and also as a parameter to feed grapevine growth models and to estimate heat and water fluxes in irrigated vineyardsinfo:eu-repo/semantics/publishedVersio

Aplicação da interferometria holografia subaquática para análise de estruturas

Pretende-se com este trabalho estudar a aplicação das técnicas de interferometria holográfica à análise estrutural em ambiente subaquático. Estas técnicas estão hoje bem divulgadas e com aplicações em diversas áreas. No entanto, a sua aplicação em ambientes subaquáticos, apresenta alguns desafios. Neste trabalho estuda-se a aplicação de duas técnicas, ESPI e holografia digital, comparando-as e apresentando vantagens e desvantagens de cada uma delas. Faz-se um breve estudo sobre a influência das instabilidades resultantes da turbulência das águas e da presença de partículas em suspensão bem como possíveis soluções para minimizar estes problemas