Descarga em barreira dielétrica: construção de um reator DBD e caracterização mediante análises ópticas e elétricas do plasma produzido

The plasma produced by Dielectric Barrier Discharge (DBD) is a promising technique for producing plasma in atmospheric pressure and has been highlighted in several areas, especially in biomedical and textile industry, this is due to the fact that the plasma generated by DBD not reaches high temperatures, enabling use it for thermally sensitive materials. But still it is necessary the development of research related to understanding of the chemical, physical and biological interaction between the non-thermal plasma at atmospheric pressure with cells, tissues, organs and organisms. This work proposes to develop equipment DBD and characterize it in order to obtain a better understanding of the process parameters of plasma production and how it behaves under the parameters adopted in the process, such as distance, frequency and voltage applied between electrodes. For this purpose two techniques were used to characterize distinct from each other. The first was the method of Lissajous figures, this technique is quite effective and accurately for complete electrical characterization equipment DBD. The second technique used was Optical Emission Spectroscopy (EEO) very effective tool for the diagnosis of plasma with it being possible to identify the excited species present in the plasma produced. Finally comparing the data obtained by the two techniques was possible to identify a set of parameters that optimize the production when combined DBD plasma atmosphere in the equipment was built precisely in this condition 0.5mm-15kV 600Hz, giving way for further work

O bibliotecário e o mercado da documentação popular: CPDCs

CARVALHO, Luciana Moreira. O bibliotecário e a diversidade do mercado da documentação popular: CPDCs. Informação & Sociedade. Estudos, João Pessoa, v. 9, n.2, p. 439-454, 1999.

Influência da suplementação de retinol palmitato sobre os níveis de vitamina A no leite de puérperas saudáveis

The tendency towards reduction of serum retinol levels, an existing placental barrier and the increase of retinol demand, are factors that place puerperal and lactating women at risk for Vitamin A deficiency. This micronutrient is an essential component of vital processes such as differentiation, cellular proliferation, and apoptosis. The objective of this study is to evaluate the effect of palmitate retinol supplementation (100.000UI) upon the milk retinollevels in puerperal women at the Januário Cicco University Maternity Hospital. This intervention has been adopted by the Ministry of Health since 2002. The longitudinal experiment was conducted with 106 puerperal women (68 comprised the supplemented group and 38 the control group). The High Performance Liquid Chromatography (HPLC) method was used to dose the retinol of the milk and serum samples, and the creamtocrit method to determine the milk fat levels. The retinol means for the colostrums were 99.0 ± 64.4 ug/dL and 160.1 ± 94,4 ug/dl 6 hours afier supplementation; 68.9 ± 33.5 ug/dL for the transitional milk, and 30.6 ± 15.2 ug/dL for the mature milk of the supplemented group. Ali the difterences between means were statistically significant. The difterence between retinol means in the control group were also significant, with these being greater in the colostrum, 88.6 ± 62.1 ug/dL with 61.9 ± 30.1 ug/dl in the transition milk and 32.9 ±32.9 ± 17.6 ug/dL in the mature milk. No significant difference was observed in the retinol means of the three types ot milk in the supplemented group when compared to their respective means in the control group. The prevalence in serum (35.1 % and 81.1 % for the cutting point 20 ug/dL, respectively) and in milk (51.4%) revealed vitamin A deficiency as a public health problem. COlostrum, transition, and mature milk tats varied similarly in the supplemented group (1,92 ± 0,96; 3,25 ± 1,27 and 3,31 ± 1,36 grams) and in the control group (1,87 ± 1,14; 3,25 ± 1,31 and 3,36 ± 1,67 grams), with an observed difference between the colostrum/transition milk and the colostrum/mature milk fats. No difference was observed between the groups. The study showed that the 200.000UI supplementation was not sufficient to increase the milk retinol to the desired levels nor to meet the demands of the mothers with deprived hepatic reserves. It is suggested that another similar dose be offered within 30 days or less, and within 2 months post-partum, while continual/y monitoring for possible pregnancy

Desenvolvimento de bloco de vedação com barita na composição de partida para blindagem de radiação X

This work main objective is to study the use of bricks in barium X-rays rooms in order to contribute to the optimization of shielding rooms diagnosis. The work was based on experimental measurements of X-ray attenuation (40 to 150 kV), using ceramic seal bearing the incorporation of barium sulfat (BaSO4). Different formulations were studied in three different firing temperatures and evaluated for incorporation in the ceramic body. The composition of 20% of barite processed at a temperature of 950 ° C showed better physical and mechanical properties, is considered the most suitable for the purpose of this work. Were produced bricks sealing composition formulated based on that presented the best technological features. These blocks were tested physically as a building material and wall protective barrier. Properties such as visual, deviation from the square, face flatness, water absorption and compressive strength were evaluated for all the blocks produced. The behavior of this material as attenuator for X-rays was investigated by experimental results which take into account mortar manufacturers barium through the different strains and compared with the reference material (Pb). The simulation results indicated that the ceramic block barium shows excellent properties of attenuation equivalence lead taking into account the energy used in diagnostic X-ray

Efeito de argilas organofílicas na estrutura e propriedades de nanocompósitos de poli(metacrilato de metila)

Nacomposites of polymers and lamellar clayminerals, has generated high scientific and technological interest, for having mechanical properties and gas barriers differentiated of polymers and conventional composites. In this work, it was developed nanocomposites by single screw extruder and injection, utilizing commercial raw material, with the goal to investigate the quality of new developed materials. It was evaluated the influence of the content and the kind of clay in the structure and in the nanocomposites properties. It was used regular and elastomeric poly (methyl methacrylate) (Acrigel LEP 100 and Acrigel ECP800) and six montmorillonites (Cloisite 10A, 11B, 15A, 20A, 25A e 30B) at the concentration of 1% e 3% in weight. The nanocomposites were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), colorimetric, optical transparency, flexural and tensile tests, Rockwell hardness and esclerometry. It was founded that is possible to obtain intercalated and exfoliated nanocomposites PMMA/MMT, and the top results was obtained in the materials with 1%in clay weight organophilizated with 2M2HT (Cloisite 15A and 20A) presented intercalate and hybrid morphology (exfoliated and flocullated). The ones that was produced with organophilizated clay with 2MHTL8 (Cloisite 30B) had excellent visual quality, but the majority presented hybrid morphology. In the materials processed with organophilizated clay with MT2ETOH (Cloisite 30B), there were color change and loss of transparency. It occurs improvement in a few mechanical properties, mainly in the materials produced with PMMA elastomeric (Acrigel ECP800), being more significant, the increase in the resistance to stripping in those nanocomposites

Estudo do comportamento de pastas compósitas cimento/sílica/poliuretana para poços de petróleo HPHT

Os poços HPHT atravessam zonas anormalmente pressurizadas e com altos gradientes de temperatura. Esses poços apresentam elevadas concentrações de tensões produzidas pelas operações de perfuração e fraturamento hidráulico, flutuações da pressão e temperatura, forças dinâmicas geradas durante a perfuração, formações inconsolidadas, entre outros aspectos, podendo resultar em falhas mecânicas na bainha de cimento. Tais falhas comprometem a estabilidade mecânica do poço e o isolamento das zonas produtoras de óleos e/ou gás. Para que operações corretivas não se façam necessárias, é preciso adequar as pastas às condições de cada poço. Sistemas de pastas de cimento para poços HPHT requerem um bom controle de suas propriedades termo-mecânicas. Visto que a temperaturas superiores a 110 oC (230 oF) o cimento, após alcançar um valor máximo de resistência, inicia um processo de perda de resistência (retrogressão). Para prevenir esse efeito substitui-se parcialmente o cimento Portland por sílica com objetivo de incrementar a reação pozolânica. Esta reação modifica a trajetória do processo natural de hidratação do cimento, o gel de silicato de cálcio hidratado (C-S-H) se converte em várias outras fases com maior resistência. Polímeros também são adicionados para proporcionar maior flexibilidade e agir como barreira à propagação de trincas desenvolvidas sob tensão. O presente trabalho teve como objetivo estudar o comportamento do sistema cimento/sílica/polímero quando submetido às condições de alta temperatura e alta pressão. Foram formuladas pastas de cimento puro, pastas contendo 40 % BWOC de sílica flour e pastas com diferentes concentrações de poliuretana (5 % a 25 %) e 40 % BWOC de sílica flour. O peso específico das pastas foi fixado em 1,87 g/cm3 (15,6 lb/gal). Os resultados demonstram que as resistências da pasta contendo 40% de sílica e das com adição de polímero foram muito superiores a da pasta de cimento puro, não ocorrendo o efeito da retrogressão. As pastas com polímero apresentaram um crescente aumento da tenacidade com o aumento da concentração da mesma, sendo assim capaz de suportar as tensões. Além de se manterem estáveis termicamente acima de 180 ºC. O sistema também apresentou excelentes resultados de filtrado, reologia, água livre, estabilidade e permeabilidade. Sendo assim, o mesmo mostrou ser aplicável a poços HPHT

Monitoramento da morfologia costeira em setores da bacia potiguar sob influência da indústria petrolífera utilizando geodésia de alta precisão e laser escâner terrestre

The objective of this Doctoral Thesis was monitoring, in trimestral scale, the coastal morphology of the Northeastern coast sections of Rio Grande do Norte State, in Brazil, which is an area of Potiguar Basin influenced by the oil industry activities. The studied sections compose coastal areas with intense sedimentary erosion and high environmental sensitivity to the oil spill. In order to achieve the general objective of this study, the work has been systematized in four steps. The first one refers to the evaluation of the geomorphological data acquisition methodologies used on Digital Elevation Model (DEM) of sandy beaches. The data has been obtained from Soledade beach, located on the Northeastern coast of Rio Grande Norte. The second step has been centered on the increasing of the reference geodetic infrastructure to accomplish the geodetic survey of the studied area by implanting a station in Corta Cachorro Barrier Island and by conducting monitoring geodetic surveys to understand the beach system based on the Coastline (CL) and on DEM multitemporal analysis. The third phase has been related to the usage of the methodology developed by Santos; Amaro (2011) and Santos et al. (2012) for the surveying, processing, representation, integration and analysis of Coastlines from sandy coast, which have been obtained through geodetic techniques of positioning, morphological change analysis and sediment transport. The fourth stage represents the innovation of surveys in coastal environment by using the Terrestrial Laser Scanning (TLS), based on Light Detection and Ranging (LiDAR), to evaluate a highly eroded section on Soledade beach where the oil industry structures are located. The evaluation has been achieved through high-precision DEM and accuracy during the modeling of the coast morphology changes. The result analysis of the integrated study about the spatial and temporal interrelations of the intense coastal processes in areas of building cycles and destruction of beaches has allowed identifying the causes and consequences of the intense coastal erosion in exposed beach sections and in barrier islands

Variação temporal da riqueza de táxons, abundância e biomassa de artrópodes em ambiente de restinga do Rio Grande do Norte, Brasil

Arthropods are abundant organisms possess great wealth and diversity representing about 82% of all known animal species. Contribute as a source of biomass and their abundance is an indicator of ecological change. The aim of this study was to evaluate the biomass and abundance found in the salt marsh environment throughout the year and relate them to the climatic factors (temperature, precipitation and relative humidity) that can influence the abundance and biomass of arthropods. The study was conducted at the Centro de Lançamento de Foguetes Barreira do Inferno, city of Parnamirim, Rio Grande do Norte, in the period February 2011 to January 2012, using pitfall traps, stationary window and beating tray. Among the 26 orders found, the most abundant were: Hymenoptera, Orthoptera, Araneae. Taxa Hymenoptera, Blattodea and Orthoptera showed higher biomass volume. Climatic factors did not influence the fall of Arthropods in the traps, however, the lowest abundance during the rainy season the action of raindrops, reduced the activity of these arthropods on vegetation, reducing its capture in traps (pitfall traps and stationary window ) and method of collection(entomological umbrella)

Aborto em adolesecentes: Ato tão praticado e tão pouco conhecido

O aborto provocado na adolescência como problema de saúde pública, é tema deste estudo que teve como objetivo identificar os motivos que levam adolescentes a provocar o aborto. A multidisciplinariedade do Programa de Pós Graduação em Ciências da Saúde, da Universidade Federal do Rio Grande do Norte, proporcionou o convívio com vários pesquisadores, bem como contribuiu para a coorientação e o crescimento deste estudo e da Pesquisadora com aquisição de conhecimentos diversificados e inovadores. Estudo transversal, quantitativo, analítico, usou questionário semi-estruturado como instrumento que foi aplicado em dez escolas. Trabalhou-se com jovens do sexo feminino, dos 12 aos 19 anos de idade. A amostra representativa foi calculada considerando-se o número de internações por curetagens na cidade de Maceió em 2004. O Banco de Dados foi analisado pelo programa Epi Info versão 3.3.2. Foram usados os testes Quiquadrado, Odds Ratio, Risco Relativo e Regressão Logística. A amostra foi de 2592 jovens, numa distribuição normal, com idade média e mediana de 15 anos, desvio padrão de 1,7. A maioria das jovens era solteira (95,7%), não trabalhava (94,1%), residia com ambos os pais (66,2%) e conhecia algum método contraceptivo (95,5%). Do total das adolescentes estudadas, 52,4% estudava o nível educacional médio. Delas 21,6% tinham vida sexual ativa, 6,4% engravidaram e 5,7 % abortaram. A maioria (95,5%) afirmou conhecer algum método contraceptivo, destas 70,1% tinha mais de 15 anos e os métodos mais citados foram os de barreira/hormonal com 72,4%. Analisando o Risco Relativo observou-se que o risco era significativo e protetor para o começo da vida sexual antes dos 15 anos de idade. Apenas 32,4% delas citaram algum tipo de complicação o aborto. Foi significativa a relação entre a idade e as citações da morte, da esterilidade como a complicação do aborto. A maioria recebeu apoio para abortar (63,8%), amigas foram as que mais apoiaram (32,9%), sendo significativa a relação entre o apoio recebido para abortar e a pratica do ato. O motivo mais citado foi o medo da reação dos pais (57,7%), esteja este motivo apontado como único ou associado a outros. A análise de significância entre as variáveis dicotômicas, forneceu 8 variáveis significativas, 2 protetoras para o abortamento: idade de 12-14 anos e conversar com os pais sobre sexo. As demais variáveis: estado marital com companheiro, vida sexual ativa, gravidez anterior, uso de método contraceptivo, recebimento de apoio para abortar e necessidade de internamento pós-aborto, foram promotoras ao abortamento. Receber apoio para abortar foi a mais significativa para abortar, estado marital com companheiro foi fator de proteção para o ato. Conclui-se que o apoio para abortar foi a variável mais significativa deste estudo reforçando a importância do grupo na adolescência. Sugere-se maior atenção as ações educativas como prevenção para riscos na saúde reprodutiva dos jovens

Seleção de categorias da Classificação Internacional de Funcionalidade, Incapacidade e Saúde para avaliação do paciente com acidente vascular cerebral em reabilitação

Stroke represents the first cause of disabilities among adults. Although different professions work together in treatment of stroke patients, all they use different terminologies for the description of the patients problems and it can constitute an impediment in the communication between the staff members. Thus, the multidisciplinary and interdisciplinary work would be facilitated if using a reference common tool, as the new International Classification of Functioning, Disability and Health (ICF). However, the ICF is very extensive and complex and due to its complexity, it has been evidenced the necessity to select its categories to become it more practical. The aim of the study was to investigate which categories of the ICF are more suitable to evaluate and to describe the stroke patient in the view of teachers and municipal public health professionals. It was a descriptive research, which involved 5 professors and 11 professionals of Physiotherapy that have worked at the health public area in Natal / RN. It was used the Delphi Technique in 3 rounds and the Likert Scale to select the categories among the ICF components. As result, from the 362 IFC categories, 94 were selected. The selected categories correspond to rehabilitative characteristics of Stroke patients in the universe of the Physiotherapy performance. The methodology applied was suitable to the studied object emphasizing the necessity of future studies for validation of the chosen categories

Caracterização sócio-demográfica, ocupacional e de formação profissional de manipuladores de alimentos e bebidas em uma capital da região nordeste do Brasil

Universidade Federal do Rio Grande do Norte

Caracterização e quantificação de marcadores químicos do extrato hidroetanólico das folhas de Kalanchoe brasiliensis Cambess

Kalanchoe brasiliensis Cambess (Crassulaceae), commonly known as saião , coirama branca , folha grossa , is originally from Brazil and commonly found in São Paulo to Bahia, mainly in the coastal zone. Regarding of biological activities, most preclinical studies were found in the literature, mainly about the anti-inflammatory activity of extracts obtained from leaves and / or aerial parts of K. brasiliensis. As regards the chemical constitution, it has been reported mainly the presence of flavonoids in the leaves of the species, but until this moment did not knows which are the active compounds. Although it is a species widely used in traditional medicine in Brazil, there is no monograph about the quality parameters of the plant drug. In this context, this study aims to characterize and quantify the chemical markers of hydroethanolic extract (HE) from the leaves of K. brasiliensis, which can be used in quality control of plant drug and derivatives obtained from this species. The methodology was divided into two parts: i. Phytochemical study: to fractionate, isolate and characterizate of the chemical (s) marker (s) of the HE from the leaves of K. brasiliensis; ii. To Developed validate of analytical method by High Performance Liquid Chromatography (HPLC)-diode array detector (DAD) to quantify the chemical (s) marker (s) of the EH. i. The EH 50% was prepared by turbo extraction method. It was then submitted to liquid-liquid partition, obtaining dichloromethane, n-butanol and ethyl acetate (AcOEt) fractions. The AcOEt fraction was selected to continue the fractionation process, because it has a chemical profile rich in flavonoids. The acOEt fraction was submitted to column chromatography using different systems for obtaining the compound Kb1. To identify this compound, it was submitted to UV analysis ii. For quantitative analysis, the EH was analyzed by HPLC, using different methods. After selecting the most appropriate method, which showed satisfactory resolution and symmetrical peaks, it was validated according to parameters in the RE 899/2003. As result, it was obtained from the AcOEt fraction the compound Kb1 (2.7 mg). Until this moment, the basic nucleus was characterized by UV analysis using shift reagents. The partial chemical structure of the compound Kb1 was identified as a flavonol, containing hydroxyls in 3 , 4 position (ring A), 5 and 7 free (ring B) and a replacement of the C3 hydroxyl by a sugar. As the analysis were performed in the HPLC coupled to a DAD, we observed that the UV spectrum of the major peaks of EH from K. brasiliensis shown similar UV spectrum. According to the literature, it has been reported the presence of patuletin glycosydes derivatives in the leaves of this species. Therefore, it is suggested that the compound Kb1 is glycosylated patuletin derivative. Probably the sugar (s) unit(s) are linked in the C3 in the C ring. . Regarding the development of HPLC analytical method, the system used consists of phase A: water: formic acid (99,7:0,3, v / v) and phase B: methanol: formic acid (99,7:0,3, v / v), elution gradient of 40% B - 58% B in 50 minutes, ccolumn (Hichrom ®) C18 (250x4, 0 mm, 5 μm), flow rate 0.8 mL / min, UV detection at 370 nm, temperature 25 ° C. In the analysis performed with the co-injection of thecompound Kb1 + HE of K. brasiliensis was observed that it is one of the major compounds with a retention time of 12.47 minutes and had a content of 15.3% in EH of leaves from K. brasiliensis. The method proved to be linear, precise, accurate and reproducible. According to these results, it was observed that compound Kb1 can be used as a chemical marker of EH from leaves of K. brasiliensis, to assist in quality control of drug plant and its derivatives

A dimensão simbólica e midiática da política e a história da dona de casa que virou guerreira : a construção da imagem pública de Wilma de Faria em 2002 e 2006

This paper examines two aspects. First, the symbolic dimension of politics and some of the elements that make up this universe, as the scenario, the representation, the myth, the spectacle, the media and the political and electoral marketing. We assume that the policy brings together a set of traits related to both reason and the human subjectivity, and can not be summed up in just a few calculations based on rationality. In the case of elections, in a process (ritual, according Irlys Barrier) of choice, there is a meeting of two systems of representations: to that transmitted by a political actor, in a scene from a particular context, based on a life trajectory unique, and the other from the public, crossed by social relations, situations own wishes, desires, expectations and unique perspectives. Between them there are the means of mass media (especially television), and with them the advent of language media and advertising applied to politics, changing the layout of public visibility and inaugurating what Rejane Accioly Carvalho will call the "aesthetics of mostrabilidade". This does not necessarily mean a preponderance of media on politics as a whole but only its adaptation to that with regard to contact with the public, the ad extra portion of the policy, according to Wilson Gomes. In a second aspect, try to apply these elements to a specific study to verify them in building an effective public image, in this case, the current governor of Rio Grande do Norte, Wilma de Faria. The concept of public image is from the book of Wilson Gomes The transformation was visible in the mass media, and relates to a conceptual image to fix "personality traits" through political history, personal conduct, action of image makers and the public reception. For this we will review some videos aired on Free Time for political propaganda in the years 2002 and 2006.

Mulheres na Política e Autonomia

The proposal of this study was to work with women in the politics, focusing on their trajectories, biographies and speeches, to catch the meanings given by themselves to their insertion in the political field. The privileged instrument of research was the autobiographical narratives of fifteen women who, in Paraíba, had participated of the electoral processes and the life partisan politics in the period from 1998 to 2008, in the state and federal scopes. This permitted us to search the dimension of their lived expericence, to understand the trajectories and the processes of autonomation of the women, in the politics. Moreover, a quantitative mapping of the feminine presence in the processes was made electoral politicians in a wider context. In a similar way, two surveys had been carried throughout the research, among others aspects, to understand that image voters and politicians they construct concerning the feminine participation in this field. These instruments were important not to lose of all the social view where these lives were developed, the places from which these women speak and locate and the social meanings originated from this participation. The research aimed to establish dialogues between knowing and fields of discipline, beyond the dichotomy of actor/structure, preventing generalizations that ignore the plurality of the individuals, to reveal some aspects of the complex and contradictory processes that involve their participation in the political field. At last, it is tried to show that, although the frequent accusations of autonomy lack, when establishing relations in the public space, the women, as all subjects, can reflect about themselves, the motives of their thoughts and their actions escaping from the servitude of the repetition and avoid being only product of the institution that formed them (CASTORIADIS, 1992, p.140-141)

O voto e seus enigmas: A dimensão subjetiva das escolhas eleitorais

Ce travail analyse la portée subjective des Choix Électoraux à travers la notion psychanalytique du désarroi humain. Nous avons développé cette recherche ayant pour référence la pensée de Freud et de Lacan et suivant les jalons posés par les penseurs des sciences sociales nous nous sommes rapprochées de la réalité sociale pour y « atteindre sur son horizon la subjectivité de notre époque ». La condition de désarroi fait partie de la structuration du sujet, du fait qu il dépend entièrement de l Autre pour se construire. Cependant l être humain se crée des mécanismes pour se protéger du désarroi absolu, il trouve des arts de vivre qui lui rendent plus facile sa condition d être. Les idéaux, les pactes sociaux ce sont des modalités de sécurité sans lesquelles le sujet fixe ses particularités sans s engager dans le processus civilisatoire. Nous caractérisons la société contemporaine par la chute successive d une série d idéaux qui fait monter de plus en plus le désarroi. Dans l absence d idéaux sociaux et politiques sur lesquels l électeur puisse se repérer, nous remaquons une tendance vers l individualisme et vers l absence d investissements dans des projets colectifs. Cette façon d opérer se dévoile aussi au moment de choisir un candidat, ce qui se base sur la logique du particulier motivée par des perspectives individuelles, sans liens avec la promotion de la vie publique. Notre enquête a été réalisée à Natal durant la campagne électorale de 2002. Notre objectif est de comprendre surtout la logique des choix électoraux de la population de la périphérie, celle qui se trouve devant un double désarroi : celle de sa condition humaine et celle qu advient de la précaire condition de subsistance. Nous soutenons que l idée selon laquelle le candidat, par la position qu il occupe dans la société, détient la fonction d offrir quelques garanties à l électeur et de cette manière il entre dans la série de ce qui peut soulager et promouvoir un certain réconfort aux personnes, même si l on considère le fait que l électeur ne croit plus à ses représentants. Nous sommes partis des questions suivantes: comment identifier la dimension subjective des choix électoraux et de quelle manière celle-ci se manifeste-t-elle de nos jours ? Comment se passe le choix éléctoral de la population qui est à la marge du système? La thèse que nous soutenons est que l état de désarroi est un substrat subjectif qui est la base de tout choix éléctoral mais qui se configure de façon différenciée à partir des références de l électeur, de son contexte historique, des facteurs économiques, etc. Le sujet, face à son désarroi, construit des chemins pour pouvoir soutenir son existence ce que nous appellons ici un Projet Directionnel. Ce facteur directionnel est l un des éléments de motivation des électeurs dans leurs choix électoraux