Morphology and stability of aggregates of an Oxisol according to tillage system and gypsum application

Morphological characterization and aggregate stability is an important factor in evaluating management systems. The aim of this paper is to evaluate the stability and morphology of the aggregates of a dystrophic Oxisol managed with no-tillage and conventional tillage with and without the residual action of gypsum. The experimental design was randomized blocks arranged in split-split plot, where the treatments were two soil management systems (plots) with 0 and 2000 kg ha-1 of gypsum (subplots) and five depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20 and 0.20-0.30 m) as the subsubplots, with four replications. The aggregate morphology was determined through images and later evaluated by the Quantporo software. Stability was determined by the wet method. The results showed that the no-tillage system, with or without gypsum residual effect, provided the aggregates with the largest geometric diameters. The combination of no-tillage system and the gypsum residual effect provided rougher aggregates.

Improving Remote Voting Security with Code Voting

One of the major problems that prevents the spread of elections with the possibility of remote voting over electronic networks, also called Internet Voting, is the use of unreliable client platforms, such as the voter's computer and the Internet infrastructure connecting it to the election server. A computer connected to the Internet is exposed to viruses, worms, Trojans, spyware, malware and other threats that can compromise the election's integrity. For instance, it is possible to write a virus that changes the voter's vote to a predetermined vote on election's day. Another possible attack is the creation of a fake election web site where the voter uses a malicious vote program on the web site that manipulates the voter's vote (phishing/pharming attack). Such attacks may not disturb the election protocol, therefore can remain undetected in the eyes of the election auditors. We propose the use of Code Voting to overcome insecurity of the client platform. Code Voting consists in creating a secure communication channel to communicate the voter's vote between the voter and a trusted component attached to the voter's computer. Consequently, no one controlling the voter's computer can change the his/her's vote. The trusted component can then process the vote according to a cryptographic voting protocol to enable cryptographic verification at the server's side.

Learning dependent sources using mixtures of Dirichlet: applications on hyperspectral unmixing

This paper is an elaboration of the DECA algorithm [1] to blindly unmix hyperspectral data. The underlying mixing model is linear, meaning that each pixel is a linear mixture of the endmembers signatures weighted by the correspondent abundance fractions. The proposed method, as DECA, is tailored to highly mixed mixtures in which the geometric based approaches fail to identify the simplex of minimum volume enclosing the observed spectral vectors. We resort then to a statitistical framework, where the abundance fractions are modeled as mixtures of Dirichlet densities, thus enforcing the constraints on abundance fractions imposed by the acquisition process, namely non-negativity and constant sum. With respect to DECA, we introduce two improvements: 1) the number of Dirichlet modes are inferred based on the minimum description length (MDL) principle; 2) The generalized expectation maximization (GEM) algorithm we adopt to infer the model parameters is improved by using alternating minimization and augmented Lagrangian methods to compute the mixing matrix. The effectiveness of the proposed algorithm is illustrated with simulated and read data.

Reasoning and proof in classroom (9th grade)

This paper is research oriented and pretends to contribute toward giving empirical evidence about how students develop their reasoning and how they achieved to a proof construction in school context. Its main theme is epistemology. It describes the way in which four students in 9th Grade explored a task related with the discovery of symmetry axes in various geometric figures. The proof constructed by students had essentially an explaining function and it was related with the symmetry axes of regular polygons. The teacher’s role in meaning negotiation of the proof and its need is described through illustrative episodes. The paper presents part of a study which purpose is to analyse the nature of mathematical proof in classroom, its role and the nature of the relationship between the construction of a proof and the social interactions. Assuming a social perspective, attention is focussed on the social construction of knowledge and on the structuring resources that shape mathematical experience. The study’s methodology has an interpretative nature. One outcome of the study discussed here is that students develop first a practical understanding with no awareness of the reasons founding mathematical statements and after a theoretical one leading them to a proof elaboration.

Dor abdominal aguda como apresentação de porfirias

As porfirias são um grupo de oito doenças metabólicas raras, em resultado de uma deficiência enzimática em cada uma das oito enzimas envolvidas na biossíntese do grupo heme. São doenças maioritariamente hereditárias, mas podem também ser adquiridas aquando da exposição a certos fatores ambientais e/ou patológicos. Estes fatores externos, denominados de porfirinogénicos também têm um papel preponderante no diagnóstico das porfirias, uma vez que mimetizam os sintomas clínicos de um ataque agudo de porfiria, contribuindo para subestimar esta doença, levando a um atraso no diagnóstico e diminuído o sucesso do prognóstico. Os ataques agudos de porfiria, nomeadamente na porfiria aguda intermitente, porfiria variegata, coproporfiria hereditária, e deficiência da desidratase do ácido delta-aminolevulínico, apesar de serem doenças multissistémicas, têm em comum como apresentação clínica, a dor abdominal aguda. A pesquisa de porfobilinogénio (PBG) na urina, através da realização do teste de Hoesch, é uma forma rápida e fácil de excluir a suspeita clínica de porfiria. Pretendemos com este trabalho, alertar para a necessidade de um diagnóstico laboratorial atempado, que pela sua simplicidade poderá descartar ou confirmar se a dor abdominal aguda, tão frequente nas urgências hospitalares, será ou não uma manifestação clínica de um ataque agudo de porfiria. Este estudo contribuirá não só para aumentar o nosso conhecimento acerca destas doenças, como também permitirá uma melhor compreensão dos mecanismos de patogenicidade das porfirias, o qual ainda permanece pouco conhecido.

Estruturas tradicionais vs. termoargila em zonas sísmicas

Com a crescente divulgação no mercado português de métodos construtivos de alvenaria resistente tipo Termoargila, compara-se neste trabalho a sua rentabilidade económica, em relação à execução em betão armado, com paredes não estruturais de alvenaria. Estudam-se três tipologias de estruturas com geometria regular (1 piso, 2 pisos, 4 pisos), em zonas sísmicas A e D segundo o Regulamento de Segurança e Acções. A análise dos resultados permite verificar a eficiência dos métodos construtivos para cada tipologia de edifício, assim como os seus custos. Analisa-se se o motivo pelo qual em Portugal não é corrente a aplicação de soluções estruturais de alvenaria resistente tipo Termoargila, se unicamente económico ou se existe uma inércia dos intervenientes na construção, privilegiando os métodos construtivos tradicionais.

Evaluation of intermolecular interactions in thioxanthone derivatives: substituent effect on crystal diversity

A family of 9H-thioxanthen-9-one derivatives and two precursors, 2-[(4-bromophenyl) sulfanyl]-5-nitrobenzoic acid and 2-[(4-aminophenyl) sulfanyl]-5-nitrobenzoic acid, were synthesized and studied in order to assess the role of the different substituent groups in determining the supramolecular motifs. From our results we can conclude that Etter's rules are obeyed: whenever present the -COOH head to head strong hydrogen bonding dimer, R-2(2)(8) synthon, prevails as the dominant interaction. As for -NH2, the best donor when present also follows the expected hierarchy, an NH center dot center dot center dot O(COOH) was formed in the acid precursor (2) and an NH center dot center dot center dot O(C=O) in the thioxanthone (4). The main role played by weaker hydrogen bonds such as CH center dot center dot center dot O, and other intermolecular interactions, pi-pi and Br center dot center dot center dot O, as well as the geometric restraints of packing patterns shows the energetic interplay governing crystal packing. A common feature is the relation between the p-p stacking and the unit cell dimensions. A new synthon notation, R`, introduced in this paper, refers to the possibility of accounting for intra- and intermolecular interactions into recognizable and recurring aggregate patterns.

Spatio-temporal alignment of pedobarographic image sequences

O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).

Intelligent supervisory control system for home devices using a cyber physical approach

Although we have many electric devices at home, there are just few systems to evaluate, monitor and control them. Sometimes users go out and leave their electric devices turned on what can cause energy wasting and dangerous situations. Therefore most of the users may want to know the using states of their electrical appliances through their mobile devices in a pervasive way. In this paper, we propose an Intelligent Supervisory Control System to evaluate, monitor and control the use of electric devices in home, from outside. Because of the transferring data to evaluate, monitor and control user's location and state of home (ex. nobody at home) may be opened to attacks leading to dangerous situations. In our model we include a location privacy module and encryption module to provide security to user location and data. Intelligent Supervising Control System gives to the user the ability to manage electricity loads by means of a multi-agent system involving evaluation, monitoring, control and energy resource agents.

Contexts-management strategy in considering the security in urban computing based on urban design

Urban Computing (UrC) provides users with the situation-proper information by considering context of users, devices, and social and physical environment in urban life. With social network services, UrC makes it possible for people with common interests to organize a virtual-society through exchange of context information among them. In these cases, people and personal devices are vulnerable to fake and misleading context information which is transferred from unauthorized and unauthenticated servers by attackers. So called smart devices which run automatically on some context events are more vulnerable if they are not prepared for attacks. In this paper, we illustrate some UrC service scenarios, and show important context information, possible threats, protection method, and secure context management for people.

Immunogenicity of WHO-17D and Brazilian 17DD yellow fever vaccines: a randomized trial

OBJECTIVE: To compare the immunogenicity of three yellow fever vaccines from WHO-17D and Brazilian 17DD substrains (different seed-lots). METHODS: An equivalence trial was carried out involving 1,087 adults in Rio de Janeiro. Vaccines produced by Bio-Manguinhos, Fiocruz (Rio de Janeiro, Brazil) were administered following standardized procedures adapted to allow blocked randomized allocation of participants to coded vaccine types (double-blind). Neutralizing yellow fever antibody titters were compared in pre- and post-immunization serum samples. Equivalence was defined as a difference of no more than five percentage points in seroconversion rates, and ratio between Geometric Mean Titters (GMT) higher than 0.67. RESULTS: Seroconversion rates were 98% or higher among subjects previously seronegative, and 90% or more of the total cohort of vaccinees, including those previously seropositive. Differences in seroconversion ranged from -0.05% to -3.02%. The intensity of the immune response was also very similar across vaccines: 14.5 to 18.6 IU/mL. GMT ratios ranged from 0.78 to 0.93. Taking the placebo group into account, the vaccines explained 93% of seroconversion. Viremia was detected in 2.7% of vaccinated subjects from Day 3 to Day 7. CONCLUSIONS: The equivalent immunogenicity of yellow fever vaccines from the 17D and 17DD substrains was demonstrated for the first time in placebo-controlled double-blind randomized trial. The study completed the clinical validation process of a new vaccine seed-lot, provided evidence for use of alternative attenuated virus substrains in vaccine production for a major manufacturer, and for the utilization of the 17DD vaccine in other countries.

Atividades de investigação em Geometria: uma experiência no 2º ano de escolaridade

Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ciências da Educação, especialidade Educação Matemática na Educação Pré-Escolar e nos 1.º e 2.º Ciclos do Ensino Básico

Avaliação de um sistema CAD na deteção de lesões em imagens mamográficas

Mestrado em Radiações Aplicadas às Tecnologias da Saúde - Área de especialização: Imagem Digital por Radiação X.

O impacto da Lei nº 37/2007 (Lei do Tabaco) no consumo de tabaco em ambiente profissional na ilha Terceira e a sua influência na produtividade e absentismo laboral

Dissertação de Mestrado, Ambiente, Saúde e Segurança, 19 de Julho de 2013, Universidade dos Açores.