Interaction between a cationic surfactant-like peptide and lipid vesicles and its relationship to antimicrobial activity

We investigate the properties of an antimicrobial surfactant-like peptide (Ala)6(Arg), A6R, containing a cationic headgroup. The interaction of this peptide with zwitterionic (DPPC) lipid vesicles is investigated using a range of microscopic, X-ray scattering, spectroscopic, and calorimetric methods. The β-sheet structure adopted by A6R is disrupted in the presence of DPPC. A strong effect on the small-angle X-ray scattering profile is observed: the Bragg peaks from the DPPC bilayers in the vesicle walls are eliminated in the presence of A6R and only bilayer form factor peaks are observed. All of these observations point to the interaction of A6R with DPPC bilayers. These studies provide insight into interactions between a model cationic peptide and vesicles, relevant to understanding the action of antimicrobial peptides on lipid membranes. Notably, peptide A6R exhibits antimicrobial activity without membrane lysis.

Simple M-factor algorithm for improved estimation of the basic maximum usable frequency of radio waves reflected from the ionospheric F-region

The equations of Milsom are evaluated, giving the ground range and group delay of radio waves propagated via the horizontally stratified model ionosphere proposed by Bradley and Dudeney. Expressions for the ground range which allow for the effects of the underlying E- and F1-regions are used to evaluate the basic maximum usable frequency or M-factors for single F-layer hops. An algorithm for the rapid calculation of the M-factor at a given range is developed, and shown to be accurate to within 5%. The results reveal that the M(3000)F2-factor scaled from vertical-incidence ionograms using the standard URSI procedure can be up to 7.5% in error. A simple addition to the algorithm effects a correction to ionogram values to make these accurate to 0.5%.

Revealing the whiteboard to blind students: An inclusive approach to provide mediation in synchronous e-learning activities

Promoting the inclusion of students with disabilities in e-learning systems has brought many challenges for researchers and educators. The use of synchronous communication tools such as interactive whiteboards has been regarded as an obstacle for inclusive education. In this paper, we present the proposal of an inclusive approach to provide blind students with the possibility to participate in live learning sessions with whiteboard software. The approach is based on the provision of accessible textual descriptions by a live mediator. With the accessible descriptions, students are able to navigate through the elements and explore the content of the class using screen readers. The method used for this study consisted of the implementation of a software prototype within a virtual learning environment and a case study with the participation of a blind student in a live distance class. The results from the case study have shown that this approach can be very effective, and may be a starting point to provide blind students with resources they had previously been deprived from. The proof of concept implemented has shown that many further possibilities may be explored to enhance the interaction of blind users with educational content in whiteboards, and further pedagogical approaches can be investigated from this proposal. (C) 2009 Elsevier Ltd. All rights reserved.

Palaeodrainage on Marajo Island, northern Brazil, in relation to Holocene relative sea-level dynamics

A large area in northeastern Marajo Island, northern Brazil, has been characterized geomorphologically, applying information acquired from Landsat imagery. This study was combined with detailed sedimentologic analysis of continuous cores, which provided a record of depositional settings developed in this area through the Holocene. The results revealed well-preserved, meandering to anastomosed drainage networks of wide palaeochannels that were superimposed by a narrower palaeochannel system. In both cases, the sedimentary record consists of sands, heterolithic deposits and muds, locally rich in plant debris. The strata are organized into fining upward successions that reach approximately 18 m thick in the wide channels and 4 m thick in the narrow channels. Sedimentary features suggestive of a coastal location for the wider palaeochannels and reworking of sediments by tidal currents include the prevalence of well to moderately sorted, rounded to sub-rounded, fine- to medium-grained sands displaying foreset packages separated by mud couplets, suggestive of tidal cycles. The data presented herein point to a rise in relative sea level reaching the Lake Arari area during the early to late/mid Holocene. This event was followed by a relative sea level drop. Tectonics seem to have contributed to an overall lowering in relative sea level in the study area since the mid-Holocene, which does not follow the same pattern recorded in other areas along the northern Brazilian coast.

Perfect Simulation of a Coupling Achieving the (d)over-bar-distance Between Ordered Pairs of Binary Chains of Infinite Order

We explicitly construct a stationary coupling attaining Ornstein`s (d) over bar -distance between ordered pairs of binary chains of infinite order. Our main tool is a representation of the transition probabilities of the coupled bivariate chain of infinite order as a countable mixture of Markov transition probabilities of increasing order. Under suitable conditions on the loss of memory of the chains, this representation implies that the coupled chain can be represented as a concatenation of i.i.d. sequences of bivariate finite random strings of symbols. The perfect simulation algorithm is based on the fact that we can identify the first regeneration point to the left of the origin almost surely.

On Approximate KKT Condition and its Extension to Continuous Variational Inequalities

In this work, we introduce a necessary sequential Approximate-Karush-Kuhn-Tucker (AKKT) condition for a point to be a solution of a continuous variational inequality, and we prove its relation with the Approximate Gradient Projection condition (AGP) of Garciga-Otero and Svaiter. We also prove that a slight variation of the AKKT condition is sufficient for a convex problem, either for variational inequalities or optimization. Sequential necessary conditions are more suitable to iterative methods than usual punctual conditions relying on constraint qualifications. The AKKT property holds at a solution independently of the fulfillment of a constraint qualification, but when a weak one holds, we can guarantee the validity of the KKT conditions.

Fingerprint Segmentation

In this thesis, a new algorithm has been proposed to segment the foreground of the fingerprint from the image under consideration. The algorithm uses three features, mean, variance and coherence. Based on these features, a rule system is built to help the algorithm to efficiently segment the image. In addition, the proposed algorithm combine split and merge with modified Otsu. Both enhancements techniques such as Gaussian filter and histogram equalization are applied to enhance and improve the quality of the image. Finally, a post processing technique is implemented to counter the undesirable effect in the segmented image. Fingerprint recognition system is one of the oldest recognition systems in biometrics techniques. Everyone have a unique and unchangeable fingerprint. Based on this uniqueness and distinctness, fingerprint identification has been used in many applications for a long period. A fingerprint image is a pattern which consists of two regions, foreground and background. The foreground contains all important information needed in the automatic fingerprint recognition systems. However, the background is a noisy region that contributes to the extraction of false minutiae in the system. To avoid the extraction of false minutiae, there are many steps which should be followed such as preprocessing and enhancement. One of these steps is the transformation of the fingerprint image from gray-scale image to black and white image. This transformation is called segmentation or binarization. The aim for fingerprint segmentation is to separate the foreground from the background. Due to the nature of fingerprint image, the segmentation becomes an important and challenging task. The proposed algorithm is applied on FVC2000 database. Manual examinations from human experts show that the proposed algorithm provides an efficient segmentation results. These improved results are demonstrating in diverse experiments.

Motion Cues Analysis for Parkinson Gait Recognition

Background: Previous assessment methods for PG recognition used sensor mechanisms for PG that may cause discomfort. In order to avoid stress of applying wearable sensors, computer vision (CV) based diagnostic systems for PG recognition have been proposed. Main constraints in these methods are the laboratory setup procedures: Novel colored dresses for the patients were specifically designed to segment the test body from a specific colored background. Objective: To develop an image processing tool for home-assessment of Parkinson Gait(PG) by analyzing motion cues extracted during the gait cycles. Methods: The system is based on the idea that a normal body attains equilibrium during the gait by aligning the body posture with the axis of gravity. Due to the rigidity in muscular tone, persons with PD fail to align their bodies with the axis of gravity. The leaned posture of PD patients appears to fall forward. Whereas a normal posture exhibits a constant erect posture throughout the gait. Patients with PD walk with shortened stride angle (less than 15 degrees on average) with high variability in the stride frequency. Whereas a normal gait exhibits a constant stride frequency with an average stride angle of 45 degrees. In order to analyze PG, levodopa-responsive patients and normal controls were videotaped with several gait cycles. First, the test body is segmented in each frame of the gait video based on the pixel contrast from the background to form a silhouette. Next, the center of gravity of this silhouette is calculated. This silhouette is further skeletonized from the video frames to extract the motion cues. Two motion cues were stride frequency based on the cyclic leg motion and the lean frequency based on the angle between the leaned torso tangent and the axis of gravity. The differences in the peaks in stride and lean frequencies between PG and normal gait are calculated using Cosine Similarity measurements. Results: High cosine dissimilarity was observed in the stride and lean frequencies between PG and normal gait. High variations are found in the stride intervals of PG whereas constant stride intervals are found in the normal gait. Conclusions: We propose an algorithm as a source to eliminate laboratory constraints and discomfort during PG analysis. Installing this tool in a home computer with a webcam allows assessment of gait in the home environment.

Triggering Solar-Powered Vehicle Activated Signs using Self Organising Maps with K-means

Solar-powered vehicle activated signs (VAS) are speed warning signs powered by batteries that are recharged by solar panels. These signs are more desirable than other active warning signs due to the low cost of installation and the minimal maintenance requirements. However, one problem that can affect a solar-powered VAS is the limited power capacity available to keep the sign operational. In order to be able to operate the sign more efficiently, it is proposed that the sign be appropriately triggered by taking into account the prevalent conditions. Triggering the sign depends on many factors such as the prevailing speed limit, road geometry, traffic behaviour, the weather and the number of hours of daylight. The main goal of this paper is therefore to develop an intelligent algorithm that would help optimize the trigger point to achieve the best compromise between speed reduction and power consumption. Data have been systematically collected whereby vehicle speed data were gathered whilst varying the value of the trigger speed threshold. A two stage algorithm is then utilized to extract the trigger speed value. Initially the algorithm employs a Self-Organising Map (SOM), to effectively visualize and explore the properties of the data that is then clustered in the second stage using K-means clustering method. Preliminary results achieved in the study indicate that using a SOM in conjunction with K-means method is found to perform well as opposed to direct clustering of the data by K-means alone. Using a SOM in the current case helped the algorithm determine the number of clusters in the data set, which is a frequent problem in data clustering.

Um estudo sobre a percepção do cliente pré-pago quanto ao serviço de roaming de chamadas terminadas

o serviço móvel celular apresentou, nos últimos anos, mudanças significativas em termos de evolução tecnológica e dos produtos e serviços oferecidos ao cliente. O ambiente de prestação do serviço evoluiu a partir de um monopólio estatal para um regime de duopólio regional privado. A introdução da competição trouxe benefícios aos clientes, dentre os quais podem ser citados a redução dos preços de aquisição e das tarifas de uso do serviço e o aumento da oferta de linhas celulares, antes em falta no mercado. A introdução do serviço pré-pago, em 1999, representou um marco na história do Serviço Móvel Celular no Brasil. O produto, adequado para usuários que querem controlar seus gastos com telefonia celular, permitiu o acesso das classes econômicas C e D ao serviço. O pré-pago trouxe vantagens e desvantagens para clientes e prestadores de serviço. Uma de suas limitações, quando lançado, era a impossibilidade de utilização do servIço fora da área de atuação da operadora ("roaming"). O problema técnico que impedia o oferecimento de roammg para chamadas terminadas foi resolvido e as empresas prestadoras adotaram estratégias distintas em relação a isso. Algumas ofereceram o serviço para todos os clientes pré-pago, indistintamente; outras segmentaram o mercado pré-pago, criando produtos novos com a facilidade de roaming e mantendo os produtos já lançados no mercado sem a facilidade de roaming. A Americel, empresa operadora do Serviço Móvel Celular na região Centro Oeste e parte da região Norte, possui dois produtos pré-pago: o primeiro, chamado Legal, não permite o roaming de chamadas terminadas. Foi criado também o Legal Pacas que oferecia, entre outras novas funcionalidades, a possibilidade de roaming de chamadas terminadas. Os dois produtos possuem outras características diferentes e planos de tarifa próprios. O objetivo da pesquisa é avaliar como o cliente pré-pago da Americel percebe a funcionalidade de roaming de chamadas terminadas. A pesquisa pretende avaliar a importância do serviço para o cliente, como ele avalia o serviço prestado pela empresa e como essa funcionalidade é classificada (básica, de desempenho ou de encantamento). A partir da compreensão da percepção do cliente quanto ao roaming, será avaliada a estratégia de marketing de segmentar o mercado pré-pago por meio dessa funcionalidade. VI A metodologia empregada utiliza-se de ferramentas de medição da satisfação dos clientes. A Americel realiza mensalmente uma pesquisa de satisfação com uma amostra de 400 clientes que são entrevistados por telefone. O questionário de pesquisa possui 50 perguntas sobre vários aspectos relacionados à prestação do serviço. Os resultados anteriores dessa pesquisa apontam a cobertura como sendo a característica mais importante do serviço do ponto de vista do cliente e, ao mesmo tempo, uma característica mal avaliada por ele. A pesquisa também demonstra uma confusão do cliente que, quando questionado sobre onde necessita de cobertura, indica regiões onde a empresa não atua e, portanto, não poderia oferecer cobertura, mas roaming. Para uma parte dos clientes, roaming e cobertura são o mesmo atributo. Foram acrescentadas ao questionário padrão perguntas relacionadas ao roaming. As perguntas foram elaboradas para avaliar a freqüência com que os clientes viajam, a importância atribuída ao roaming, a avaliação do serviço de roaming e a avaliação geral da Americel. Os resultados permitem concluir que, apesar do usuário do serviço pré-pago não viajar freqüentemente, ele considera a funcionalidade de roaming como importante ou muito importante. A avaliação do serviço é ruim, o que implica na necessidade de priorizar ações no sentido de melhorar o serviço de roaming para os clientes pré-pago. Isso pode ser feito através da extensão do oferecimento do roaming a todos os clientes pré-pago. O resultado da análise penalidade-recompensa foi de que a funcionalidade de roaming é uma funcionalidade de desempenho do Serviço Móvel Celular. Isso significa que sua ausência causa insatisfação do cliente, enquanto sua presença aumenta a sua satisfação. Sendo assim, mais uma vez é confirmada a necessidade de oferecimento dessa facilidade a toda a base de clientes pré-pago. A pesquisa permite, então, concluir que a estratégia de marketing de segmentar o mercado de clientes pré-pago por meio do uso da facilidade de roaming tem como conseqüência final a insatisfação do cliente, uma vez que, de acordo com sua percepção, o roaming é uma funcionalidade importante do serviço móvel celular, que deve ser oferecido para toda a base de clientes. As características do serviço que devem ser usadas para segmentação devem ser aquelas que, quando ausentes, não causam insatisfação nos clientes, mas, quando presentes, o encantam.

Marketing de relacionamento como Estratégia de otimização da carteira de clientes: o caso de uma empresa operadora de planos de saúde no Rio Grande do Sul

Os serviços em geral estão em evolução dentro de um cenário de crescente competição, e as particularidades de cada segmento necessitam ser atendidas de forma manter os clientes atuais ampliar carteira dentre os clientes potenciais. papel do relacionamento nas atividades de serviços torna-se cada dia mais importante, em especial se setor da atividade da saúde. saúde um setor onde tecnologia pouco contribui para redução dos custos; ao contrário, encarece prática da medicina, juntamente com acréscimo da demanda das expectativas dos usuários. Além disso, setor passou para condição de concessionário, regulamentado por uma Agência governamental, com forte pressão de nova legislação qual aumentou significativamente as coberturas serem entregues pelos Planos de Saúde seus usuários, ampliada pelos órgãos de defesa do consumidor pela exposição na mídia, por tratar-se de assunto de forte apelo social, econômico político. estudo analisa, através de uma pesquisa, importância de um programa de Marketing de Relacionamento desenvolvido por um Grupo que presta serviços de saúde no interior do Rio Grande do Sul, qual procura manter os clientes atuais ampliar sua carteira. organização desenvolve um programa valorizando os colaboradores, orienta-se para mercado busca fortalecer as relações internas externas, por meio do comprometimento, da confiança da cooperação, que são as bases do relacionamento. Os resultados apontam para validade do programa no tocante fidelização dos atuais clientes, sua evolução permite prever fortalecimento dos vínculos do Grupo com seus colaboradores clientes, necessitando de mais tempo para confirmar eficácia também na ampliação de sua carteira.

Geologia e geoquimica do complexo cambaizinho, sao gabriel - RS

Mapeamentos geológicos feitos pelo autor na região do Arroio Cambaizinho - são Gabriel/RS, resultaram na definição do Complexo Cambaizinho, representado pelas seqüências meta-sedimentar e máfica-ultramáfica, intimamente associadas ao longo de toda a extensão da associação supracrustal. A seqüência meta-se dimentar é constitu1da por gnaisses quartzo-feldspáticos dominan tes, anfibolitos bandados e quartzitos subordinados, derivados de sedimentos areno-pelítico-carbonatados estruturados, de forma ritmica em ambiente subaquoso. Niveis composicionais de ocorrência restrita contendo estaurolita, definem o grau metamórfico (médio) para esta região. Intercalações de serpentinitos, xistos magnesianos variados e anfibolitos a granulação fina, na forma de camadas e/ou lentes interestratificadas nos meta-sedimentos indicam suas derivações a partir de derrames e/ou intrusões , ígneas de pequena profundidade de composição básica-ultrabásica. Este juntamente com níveis de sedimentos qu1micos intercalados e corpos de gabros, constituem a seqüência máfica-ultramáfica. O complexo, representa o segmento norte de um cintu rão supracrustal polideformado de forma geométrica aproximadamente linear, com orientação NNE, que se extende desde a localidade de Passo do Ivo, situado mais a sul, até a região objeto deste trabalho. Quatro fases de deformação dúcteis foram das para a área, estando as duas primeiras (Dl e D2) identifica associadas xx aos eventos metamórficos regionais Ml e M2. O metamorfismo mais antigo (Ml), assinalado por paragêneses diagnósticas em metapelitos alcançou o fácies anfibolito (zona da estaurolita), estando representado em outras litologias pela ocorrência de olivina metamórfica em paragênese com tremolita e/ou talco (meta-serpentinitos) e hornblenda mais oligoclásio/andesina em meta-básicas. O M2, mais jovem, atingiu o fácies xistos verdes, cujas assembléias mineralógicas se associam à foliação S2, de distribuição ir regular ao longo do cinturão. As condições fisicas de Ml foram de média P/T, similares às do metamorfismo Dalradiano. Intrusões graniticas na forma de lâminas (corpos ta bulares) durante a segunda fase de deformação D2, datados pelo mé todo Rb/Sr em 661 :: 29 Ma e agrupados sob a denominação de Granatóides Sanga do Jobim, fornecem idades mínimas para o complexo. Os vários grupos composiciconais da seqüência máfic~ -ultramáfica, individualizados com base em critérios petrográf~ cos e conteúdo de elementos maiores correspondem a: serpentinitos e olivina-talco ultramafitos (cumulados komatilticos); xis tos magnesianos à talco e clorita e anfibólio xistos (komatiitos); clorita-hornblenda xistos (basaltos komatiiticos), litos e metagabros (basaltos e gabros tolelticos). anfibo Estes vários tipos litológicos foram originados através de diferentes graus de fusão parcial do manto como indicado pelo hiato composicional de MgO (11 à 17%) e os diferentes padrões de ETR existentes entre os anfibolitos/metagabros (toleitos) e os serpentinitos/xistos magnesianos (komatiltos).As variações composicionais no interior de cada grupo, foram controladas pelo fracionamento (acumulação ou extração) de olivina e pouco ortopiroxênio (serpentinitos e olivina-talco ultramafitos)clinopiroxênios (clorita e anfibólios xistos, clorita hornblenda xistos), clinopiroxênio e plagioclásio (anfibolitos e metagabros). As abundâncias e os padrões de ERTL (elementos terras raras leves) enriquecidos, juntamente com os baixos valores das razões A1203/Ti02 e CaO/Ti02 das amostras de xistos magnesiinos das camadas A e B sugerem derivações deste material a partir de baixas percentagens de fusão de um manto enriquecido em mentos incompatíveis. As anomalias negativas de Ce e Eu na ele maio ria das rochas da seqüência máfica-ultramáfica indicam que protólitos ígneossofreram alterações em ambiente submarino.

Significados e percepções de puérperas sobre as síndromes hipertensivas da gravidez e parto prematuro

Hypertensive syndromes in pregnancy (HSP) are configured as one of the major complications in the pregnancy and postpartum period and can lead premature newborn and subsequent hospitalization of the newborn to the Neonatal Intensive Care Unit (NICU). This study aimed to analyze the perceptions, meanings and feelings of mothers on the hypertensive syndromes in pregnancy and premature obstetric labor. The research was qualitative and has a theoretical methodological the Social Representations Theory(SRT) in the approach to the Central Nucleus Theory. The study included 70 women, mean age 29 years, predominantly school to high school, most of them married or in consensual union, primiparous and prevalence of cesarean delivery occurred between 32 and 37 weeks of pregnancy.The data were collected from may to december 2008 in the Maternity School Januário Cicco in Natal , and obtained through the following instruments for data collection: questionnaire including questions about socio-demographic status; the Free Words Association Test (FWAT) and and verbalized mental image construction used three stimuli: such as pregnancy with high blood pressure, preterm birth and NICU, and interview with the following guiding question: what it meant for you to have a pregnancy with high blood pressure and consequently the birth of a premature baby? Data analysis was performed using multi-method obtained from the data processing by EVOC (Ensemble Programmes Permettant L 'Analyze des Évocations) and ALCESTE (Analyse Lexicale par Contexte d'un Ensemble de Segment de Texte) and thematic analysis in categories. The results will be presented in four thematic units under the following representative universes: HSP, prematurity as a result of HSP, NICU and the social representations of mothers on the hypertensive disorder of pregnancy sequenced premature birth and hospitalization of the child in the NICU. The results obtained by multimethod analyses showed similar constructions and point to death as the central nucleus and negative aspects, coping strategies, need of care, knowledge about the disease, fragility and meanings of the NICU as peripheral elements. It is considered that the perceptions, meanings and feelings of puerperal women in relation to HSPs and to premature delivery are a negative social representation, with representational elements that may have influenced the adverse effects on the disease and its consequences. We suggest action on the peripheral elements of this representation, with adequate orientation, early diagnosis, effective conduct, receptive attitude on the part of the team, health promotion measures and effective public policies, in order to improve the care provided to puerperal women, making them feel welcome and minimizing their suffering

Seis sigma :uma proposta para implementação da metodologia em pequenas e médias empresas

The Six Sigma methodology consists of a program guided to the continuous improvement of enterprise processes, which aims at customer satisfaction, as well as increasing financial and operational profits. Considering that more than 99% of the Brazilian companies have up to five hundred employees, this study investigates how Six Sigma can be applied in small or medium size companies. This study was conducted based on literature review and application of the ideas in a medium size newspaper company, which manufactures newspapers that circulate daily in the state of Rio Grande do Norte. The results of the research point to the viability of use of the methodology in this market segment, as well as suggest a method that can be used in similar companies

Otimização de superfícies seletivas de frequência com elementos pré-fractais utilizando rede neural MLP e algoritmos de busca populacional

This thesis describes design methodologies for frequency selective surfaces (FSSs) composed of periodic arrays of pre-fractals metallic patches on single-layer dielectrics (FR4, RT/duroid). Shapes presented by Sierpinski island and T fractal geometries are exploited to the simple design of efficient band-stop spatial filters with applications in the range of microwaves. Initial results are discussed in terms of the electromagnetic effect resulting from the variation of parameters such as, fractal iteration number (or fractal level), fractal iteration factor, and periodicity of FSS, depending on the used pre-fractal element (Sierpinski island or T fractal). The transmission properties of these proposed periodic arrays are investigated through simulations performed by Ansoft DesignerTM and Ansoft HFSSTM commercial softwares that run full-wave methods. To validate the employed methodology, FSS prototypes are selected for fabrication and measurement. The obtained results point to interesting features for FSS spatial filters: compactness, with high values of frequency compression factor; as well as stable frequency responses at oblique incidence of plane waves. This thesis also approaches, as it main focus, the application of an alternative electromagnetic (EM) optimization technique for analysis and synthesis of FSSs with fractal motifs. In application examples of this technique, Vicsek and Sierpinski pre-fractal elements are used in the optimal design of FSS structures. Based on computational intelligence tools, the proposed technique overcomes the high computational cost associated to the full-wave parametric analyzes. To this end, fast and accurate multilayer perceptron (MLP) neural network models are developed using different parameters as design input variables. These neural network models aim to calculate the cost function in the iterations of population-based search algorithms. Continuous genetic algorithm (GA), particle swarm optimization (PSO), and bees algorithm (BA) are used for FSSs optimization with specific resonant frequency and bandwidth. The performance of these algorithms is compared in terms of computational cost and numerical convergence. Consistent results can be verified by the excellent agreement obtained between simulations and measurements related to FSS prototypes built with a given fractal iteration