Large-Scale Convex Optimization via Saddle Point Computation

This article proposes large-scale convex optimization problems to be solved via saddle points of the standard Lagrangian. A recent approach for saddle point computation is specialized, by way of a specific perturbation technique and unique scaling method, to convex optimization problems with differentiable objective and constraint functions. In each iteration the update directions for primal and dual variables are determined by gradients of the Lagrangian. These gradients are evaluated at perturbed points which are generated from current points via auxiliary mappings. The resulting algorithm suits massively parallel computing. Sparsity can be exploited efficiently. Employing simulation of parallel computations, an experimental code embedded into GAMS is tested on two sets of nonlinear problems. The first set arises from multi-stage stochastic optimization of the US energy economy. The second set consists of multi-currency bond portfolio problems. In such stochastic optimization problems the serial time appears approximatively proportional to the number of scenarios, while the parallel time seems independent of the number of scenarios. Thus, we observe that the serial time of our approach in comparison with Minos increases slower with the problem size. Consequently, for large problems with reasonable precision requirements, our method appears faster than Minos even in a serial computer

Development and application of model selection methods for investigating brain function

The goal of any scientific discipline is to learn about nature, usually through the process of evaluating competing hypotheses for explaining observations. Brain research is no exception. Investigating brain function usually entails comparing models, expressed as mathematical equations, of how the brain works. The aim of this thesis is to provide and evaluate new model comparison techniques that facilitate this research. In addition, it applies existing comparison methods to disambiguate between hypotheses of how neuronal activity relates to blood ow, a topic known as neurovascular coupling. In neuroimaging, techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) allow to routinely image the brain, whilst statistical frameworks, such as statistical parametric mapping (SPM), allow to identify regionally specific responses, or brain activations. In this thesis, SPM is first used to address the problem of neurovascular coupling, and compare different putative coupling functions, which relate fMRI signals to different features of the EEG power spectrum. These inferences are made using linear models and a model selection approach based on F-tests. Although valid, this approach is restricted to nested models. This thesis then focuses on the development of a Bayesian technique, to construct posterior model probability maps (PPMs) for group studies. PPMs are analogous to F-tests but not limited to nested hypotheses. The work presented here then focuses again on neurovascular coupling, this time from a mechanistic perspective, not afforded by linear models. For this purpose, a detailed biophysical framework is used to explore the contribution of synaptic and spiking activity in the generation of hemodynamic signals in visual cortex, using simultaneous EEG-fMRI. This approach is a special case of brain connectivity models. Finally, using fMRI data, this thesis validates a recently proposed Bayesian approach for quickly comparing large numbers of connectivity models based on inverting a single model

Component-Resolved in Vitro Diagnosis in Peach-Allergic Patients

BACKGROUND: The in vitro diagnosis of pollen-related food allergy presents low specifi city and reproducibility with many conventional extracts. This can be improved using natural purifi ed allergens, recombinant purifi ed allergens, or both. OBJECTIVE: We compared specifi c immunoglobulin (Ig) E determination (sIgE), the basophil activation test (BAT), the histamine release test (HRT), and the cellular allergen stimulation test (CAST) using natural and recombinant allergens in the diagnosis of peach allergy. METHODS: Thirty-two peach allergic patients were studied. Skin prick tests were performed with commercial peach and extract with Mal d 1, nPru p 3, and profi lin (nPho d 2). sIgE, BAT, CAST, and HRT were determined using rPru p 3, rMal d 3, rBet v 1, rMal d 1, and rMal d 4. RESULTS: Agreement between the techniques was good with all the allergens, except HRT with rMal d 1 and rMal d 4. With rPru p 3, sIgE, CAST, BAT, and HRT showed sensitivity values of 88%, 81%, 72%, and 69% and specifi city values of 100%, 93%, 97%, and 83%, respectively. In patients with systemic symptoms or contact urticaria, the values were 100%, 85%, 81%, and 81%. In patients with oral allergy syndrome, sensitivity to profi lins or homologues of Bet v 1 was detected in 100% of the cases by all the techniques, except by HRT with rMal d 1, which detected 66% of the cases. CONCLUSIONS: The use of single allergens in the in vitro diagnosis of peach allergy by specifi c IgE determination, BAT, and CAST offers high specifi city and sensitivity, with better results than the HRT

Study of the three-dimensional shape and dynamics of coronal loops observed by Hinode/EIS

We study plasma flows along selected coronal loops in NOAA Active Region 10926, observed on 3 December 2006 with Hinode's EUV Imaging Spectrograph (EIS). From the shape of the loops traced on intensity images and the Doppler shifts measured along their length we compute their three-dimensional (3D) shape and plasma flow velocity using a simple geometrical model. This calculation was performed for loops visible in the Fe VIII 185 Ang., Fe X 184 Ang., Fe XII 195 Ang., Fe XIII 202 Ang., and Fe XV 284 Ang. spectral lines. In most cases the flow is unidirectional from one footpoint to the other but there are also cases of draining motions from the top of the loops to their footpoints. Our results indicate that the same loop may show different flow patterns when observed in different spectral lines, suggesting a dynamically complex rather than a monolithic structure. We have also carried out magnetic extrapolations in the linear force-free field approximation using SOHO/MDI magnetograms, aiming toward a first-order identification of extrapolated magnetic field lines corresponding to the reconstructed loops. In all cases, the best-fit extrapolated lines exhibit left-handed twist (alpha < 0), in agreement with the dominant twist of the region.Comment: 17 pages, 6 figure

Assessing customer satisfaction and loyalty in the retail sector

info:eu-repo/semantics/publishedVersio

Sucesso escolar nas escolas secundárias portuguesas : a importância da gestão do desempenho

info:eu-repo/semantics/publishedVersio

Initial in vitro evaluations of antibacterial activities of glucosinolate enzymatic hydrolysis products against plant pathogenic bacteria

Aims: The aim of the study was to evaluate the in vitro antibacterial effects of glucosinolate hydrolysis products (GHP) against plant pathogenic micro-organisms namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas juglandis. Methods and Results: Using a disc diffusion assay, seven different doses of 10 GHP were tested against each bacteria. The results showed that the isothiocyanates were potent antibacterials, whilst the other GHP were much less efficient. Moreover, the antibacterial effects were dose-dependent, increasing with the dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest inhibitory effects. The overall results show a great potential for using the isothiocyanates as an alternative tool to control undesired bacterial growth in plants. Conclusions: Glucosinolate hydrolysis products and more specifically the isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate Mix and sulforaphane, were effective phytochemicals against the in vitro growth of the phytopathogenic bacteria. The antibacterial activity exhibited by these phytochemicals reinforces their potential as alternatives to the traditional chemical control of phytopathogenic bacteria. Significance and Impact of the Study: This current in vitro study is the first providing comparative data on GHP as potential control agents for plant pathogenic bacteria. However, more studies are needed to determine their possible allelopathic impacts e.g. inhibition of plant growth and negative effects on beneficial soil bacteria and fungi (mycorrhizae

Evaluación De Métodos Indirectos Para Estimar Biomasa En Un Pastizal Natural Del Sur De Córdoba (Argentina Central)

To optimize grassland management, it is important to evaluate seasonal changes in quality and production according to the characteristics of the environment, allowing planning and rational use of resources. With the objective of finding estimators that fit the actual production of aerial biomass in natural pastures, it was proposed to estimate biomass with the average height of the pasture and by double sampling, by determination by direct weight estimation and by estimation with index assignment. For this purpose, a natural grassland located in the area of influence of the final section of the Chucul River Basin (La Felipa Natural Reserve) was surveyed. Periodically from April 2013 to March 2016, in ten samples taken with 0.25 m2 quadrants, the biomass was cut and weighed, and the height of the present species was measured. In the area surrounding each quadrant, 50 uncorrected visual observations were made by assigning indexes from 1 to 5 and values of estimated weight according to the amount of forage available. Then a correlation analysis was performed and linear regressions were determined between the parameters studied. Real biomass (BR) showed a significant correlation with biomass estimated by Weight (BEP) and biomass estimated by Index (BEI) (p≤0.05)

Parasitismo gastrintestinal e o seu controlo em asininos residentes nas Salinas do Samouco – Alcochete, Portugal

Apresentação em painelIntrodução As alterações sócioeconómicas ocorridas em Portugal nos últimos 100 anos, a crescente mecanização da agricultura e o desenvolvimento dos transportes, levaram à redução e ao abandono da Raça asinina Mirandesa. Atualmente são utilizados como animais companhia, em asinoterapia e em atividades ecoturísticas, estando assim associados a um extenso património social, cultural, económico e ecológico que importa preservar. Objetivos Com este trabalho pretendeu-se avaliar o tipo e grau de parasitismo e o controlo do Período de Reaparecimento de Ovos (PRO), com vista à implementação de um programa profilático no núcleo de oito asininos residentes (seis adultos e duas crias) na Fundação para a Proteção e Gestão Ambiental, nas Salinas do Samouco, sob responsabilidade da câmara municipal de Alcochete. Material e métodos O estudo decorreu entre abril e dezembro de 2011, com recolhas de fezes, quinzenalmente, a cada animal. Realizaram-se exames coprológicos qualitativos (técnica de Willis) e quantitativos (técnica de McMaster) e coproculturas. No total, realizaram-se 18 colheitas. Os animais foram desparasitados com ivermectina (Eqvalan®), e a sua eficiência foi avaliada pelo PRO. Resultados Nas amostras de fezes analisadas, identificaram-se ovos de estrongilídeos gastrintestinais (EGI), nos animais adultos e de Strongyloides sp. e ascarídeos, em apenas dois animais, nascidos durante o estudo. As médias de eliminação de ovos de estrongilídeos por grama de fezes (OPG) variaram entre 0 EGI/OPG e 557 EGI/OPG; no entanto, uma das fêmeas em período de periparto, apresentou eliminações severas com o valor máximo de 2700 EGI/OPG. Identificaram-se larvas de terceiro estadio dos géneros Strongylus, Triodontophorus, Cyathostomum e Trichostrongylus. O género Cyathostomum foi o mais frequente, tendo-se identificado em todos os animais. Conclusões O tipo e o grau de parasitismo registados foram idênticos aos referidos por outros autores para esta espécie animal. Apesar do PRO ter ocorrido aos 60 dias após a desparasitação, as médias de eliminação acima dos 200 EGI/OPG, só se registaram aos 120 dias. Os machos apresentarem sempre infeções ligeiras e as fêmeas, 150 dias após a desparasitação, evidenciaram infeções mais severas, com médias de eliminação superiores a 550 EGI/OPG, pelo que o efetivo foi novamente desparasitado. As médias de eliminação ao longo do presente estudo sugerem a implementação de um esquema de tratamento bianual. Abstract Introdution The socio-economic changes that occurred in Portugal over the past 100 years, the increasing of mechanization of agriculture and transport development, led to a reduction and breeding pause of asinine Mirandesa breed. Nowadays asinine are used but as pets, in hippotherapy, in eco-tourism, thus being related to a vast social, cultural, economic and ecological heritage that should be preserved. Aims This work intended to evaluate the type and degree of parasitism and to check out for the Egg Reappearance Period (ERP), aiming to implement a prophylactic program in the nucleus of donkeys residents of the Foundation for Environmental Protection and Management in the Salinas Samouco by responsibility to the municipal council of Alcochete. Material and methods This study took place between Abril and December 2011 with a fortnight faeces sampling for each animal. Coprological exams by qualitative (Willis technique) and quantitative (McMaster techniques) and coprocultures were performed. The donkeys were dewormed with ivermectin (Eqvalan ®), and its effectiveness was evaluated by ERP. Results In stool samples analyzed, gastrointestinal strongyle (GS) eggs were identified in adult animals and Strongyloides sp. and ascaridids in animal born in April. The average of strongyle egg output ranged from 0 GS / EPG to 557 GS / EPG, however, one of the females showed high egg output rates (ranging from 1000 GS / EPG to a maximum of 2700 GS / EPG). Coprocultures allowed the identification of four different infective larvae: Strongylus, Triodontophurus, Cyathostomum and Trichostongylus.The genera Cyathostomum was the most frequent, identified in all animals. Conclusions The type and degree of parasitism was similar to that reported by other authors for this species. In spite of the occurrence of ERP 60 days after deworming, the average of egg output above 200 GS/EPG, only occurred 120 days after deworming. The males always showed light infections, by opposite females 150 days after deworming revealed more severe infections with the egg output average above > 550 GS/EPG, which was decisive for the administration of another deworming of all the animals. Thus, the egg output average observed during this study suggested the implementation of a biannual deworming program