Espectros fractais em sistemas nanoestruturados e cristais fotônicos

The study of the elementary excitations such as photons, phonons, plasmons, polaritons, polarons, excitons and magnons, in crystalline solids and nanostructures systems are nowdays important active field for research works in solid state physics as well as in statistical physics. With this aim in mind, this work has two distinct parts. In the first one, we investigate the propagation of excitons polaritons in nanostructured periodic and quasiperiodic multilayers, from the description of the behavior for bulk and surface modes in their individual constituents. Through analytical, as well as computational numerical calculation, we obtain the spectra for both surface and bulk exciton-polaritons modes in the superstructures. Besides, we investigate also how the quasiperiodicity modifies the band structure related to the periodic case, stressing their amazing self-similar behavior leaving to their fractal/multifractal aspects. Afterwards, we present our results related to the so-called photonic crystals, the eletromagnetic analogue of the electronic crystalline structure. We consider periodic and quasiperiodic structures, in which one of their component presents a negative refractive index. This unusual optic characteristic is obtained when the electric permissivity and the magnetic permeability µ are both negatives for the same range of angular frequency ω of the incident wave. The given curves show how the transmission of the photon waves is modified, with a striking self-similar profile. Moreover, we analyze the modification of the usual Planck´s thermal spectrum when we use a quasiperiodic fotonic superlattice as a filter.

Avaliando o impacto da utilização de renderizações panorâmicas para a navegação em ambientes virtuais

Panoramic rendering is the visualization of three-dimensional objects in a virtual environment through a wide viewing angle. This work investigated if the use of panoramas is able to promote faster searches in a virtual environment. Panoramas allow the presentation of space through less need to change the orientation of the camera, especially for the case of projections spanning 360º surrounding the user, which can benefit searching. However, the larger the angle, more distorted is the visualization of the environment, causing confusion in navigation. The distortion is even bigger when the user changes the pitch of the camera, by looking up or down. In this work we developed a technique to eliminate specifically the distortions caused by changes in pitch, which was called hemispheric projection. Experiments were done to evaluate the performance of search navigation through perspective, cylindrical and hemispherical projections. The results indicate that navigating with perspective projection is superior than navigating with panoramic projections, possibly due to factors such as (i) lack of experience of the participants in understanding the scenes displayed as panoramas, (ii) the inherent presence of distortion in panoramic projections and (iii) a lower display resolution because the objects are presented in smaller sizes in panoramic projections, making the perception of details more difficult. However, the hemispherical projection was better than the cylindrical, indicating that the developed technique provides benefits for navigation compared to current techniques of panoramic projection. The hemispheric projection also provided the least amount of changes of camera orientation, which is an indication that the hemispheric projections may be particularly useful in situations where there are restrictions on the ease to change the orientation. Future research will investigate the performance of cameras interactions on slower devices, such as using only keyboard, or brain-machine interfaces

A responsabilidade enunciativa na sentença judicial condenatória

The Textual Analysis of Discourse has its origin in Text Linguistics and it aims at studying the co(n)text meaning production based on the analysis of concrete texts by offering elements to the understanding of the text as a discourse practice throughout the plans or levels of linguistic analysis. In this perspective, we intend to investigate the enunciative responsibility phenomenon in the sentencing court judgment. To do so, we review the theoretical contributions of Textual Analysis of Discourse (ADAM, 2011) and the Enunciative Linguistics from various authors, among them, Rabatel (1998, 2003, 2004, 2005, 2008, 2009, 2010), Nølke (2001, 2005, 2009, 2013), Nølke, Fløttum and Norén (2004), Guentchéva (1994, 1996) and Guentchéva et al. (1994). In this direction, we investigate the enunciative responsibility through a range that comprises the phenomenon from four gradations, each one with a kind of point of view (PoV) and with links that may mark the assumption or the distance from the point of view. Regarding the legal approach of the thesis, our theoretical anchoring follows several authors, among them, Petri (1994), Soto (2001), Alvarez (2002), Alves (2003), Cornu (2005), Albi (2007), Bittar (2010), Asensio and Polanco (2011), López Samaniego (2006), López Montolío and Samaniego (2008), Montolío (2002, 2010, 2011, 2012, 2013), Sterling (2010), Prieto (2013), Lawrence and Rodrigues (2013) and Rodrigues, Passeggi and Silva Neto (2014). Our corpus is composed of 13 sentences from criminal cases arising from the district of Currais Novos-RN, completed in 2012. The results reveal how the judge, from various enunciative instances, builds the court decision, which allowed us to understand the configuration of (non) assumption of enunciative responsibility in the sentencing court judgment discourse genre. In conclusion, we perceive that the discourse units are envisaged or through the assumption, or the non assumption of PoV by the enunciative instances, what guides the producer organization argumentative text and his (her) communicative purposes. With that, the judge creates and/or modifies values and beliefs, induces and/or guides his (her) interlocutor by being able to demonstrate objectivity and/or preventing his (her) face through the mediated constructions or engage through the assumption of the enunciative responsibility of the propositional content of an utterance. In short, we reaffirm our belief that the (non) assumption of the enunciative responsibility configures as an argumentative mechanism strongly marked by the producer of the text with a view to their communicative purposes. The sentence, therefore, is constructed in this game of taking and/or not taking of statements according to argumentative orientation and the objectives of the text producer.

Quintosana e seus derivados conjugados com ácido gálico: avaliação de seu potencial antioxidante e de interferência na formação de cristais de oxalato de cálcio

Chitin is the second most abundant polysaccharide in nature and its derivative chitosan has been widely studied due to its unique chemical and pharmacological properties. However, studies show that when this molecule is used as food, drug, etc. it tends to accumulate in renal tissue and promotes an increase in calcium excretion. Nevertheless, the effect of chitosan on the formation of calcium oxalate (OxCa) crystals has never been evaluated. The formation of kidney stones (urolithiasis) is the disease that most often affects the kidneys and the urinary system. In addition, this is a disease with high prevalence and recurrence. Many molecules with antioxidant activity have been shown to decrease the potential for in vitro OxCa crystals formation. Thus, the aim of this study was to evaluate the effect of low molecular weight chitosan and its derivatives conjugated to gallic acid (AG) as antioxidant and inhibitor of OxCa crystals formation. The physico-chemical analysis confirmed the identity of chitosan. This molecule was subjected to five antioxidant tests and showed an excellent copper chelating activity. However, chitosan did not show other significant antioxidant activity. When chitosan was subjected to in vitro crystal formation tests, it increased the number of OxCa monohydrate crystals, modified the morphology of the crystals, modified the proportions between populations of crystals in solution and increased the zeta potential of these crystals formed. Four molecules of chitosan conjugated with GA were obtained. The physico-chemical analysis confirmed that chitosan and AG were covalently bonded. However, the amount of GA liked to chitosan did not increase even when 10 times more GA was used in experiment. When these derivatives were subjected to antioxidant tests, all chitosan conjugates showed higher antioxidant potential than their precursors. However, they showed different activity between them, which indicating that the position where AG is conjugated is an important factor for chitosan-GA activity. When conjugated chitosans were submitted to in vitro crystal formation tests, a reduction in the crystals number was observed when compared with those formed in the presence of unconjugated chitosan. Chitosan has a strong capacity for inducing OxCa monohydrate crystal formation, as well as modify their morphology and zeta potential. Over all, the process of conjugating AG to chitosan led to an increase in antioxidant potential of this molecule and was also able to decrease its capacity of inducing in vitro crystal formation

O canto dos vestibulandos em 140 caracteres: linguagem e construção de identidades no Twitter

The revolution caused by the internet and its various social networks eventually bring forth fruitful reflections on cyberculture and the power of identity construction. What seemed purely fashion has become way of being, representation of self, reality creation (Lévy, 1996). Considering language as a social phenomenon, which occurs through interaction, as explicit in Bakhtin (1929), the speech aired on social networks shapes the profile of their users, constructing identities which, according to Hall (2006), are multiple and non-permanent . This research seeks to examine the use of Twitter by school students, developing a reflection on the construction of their own identities in cyberspace. The subjects are students of Educandário Nossa Senhora das Vitórias, private school in Assú/RN, all graduates from high school. Understanding the Vestibular year as a decisive and a reflection engine ever present about their condition of students, subjects eventually express their anxieties, fears and perspectives in the virtual environment, providing us with enough material to analyze how they are high school students, expectations for appropriate selection processes, plus several representations belonging to the school environment. From the discourse conveyed on Twitter expressed in Featured posts, this study reveals the identities of high school students that emerge from it, which led the cast of some evidence. From them, despite the multiplicity of identities observed, presented some common aspects that corroborate the requirements provided for specific objectives, such as: feeling of belonging to a group - class and school; change of routine and behavior towards education; desecration of traditional teaching practices; changing the identity of students'writings. The analysis of postings enables us to know the perceptions of students regarding the school, the disciplines , the pace of studies, interest in school practices, and from such evidence, the perception of how vestibular modify your daily life and a fondness their identities as school students.

Habitus e prática docente nas escolas do ensino fundamental I em Parnamirim-RN

The notion of habitus, developed by Pierre Bourdieu, and laying it down with the teaching practice and vice versa comprise the analysis undertaken here. Naturally, concepts such as field, capital and symbolic power, also prepared by him throughout their sociological research, represent important tools in this research work about the components that make up the Faculty practice. Thus, we focus on the actions that characterize this practice and which has the habitus its triggering mechanism, i.e. a device that not only produces the actions, but also changes from them. Based on this perspective, therefore, we are using as methodological feature the collective subject discourse (DSC) and your software (Qualiquantsoft), which aim to understand how certain collective thinking regarding the issues that afflict him. In addition, we undertook during the fieldwork, participant observation techniques as a tool to capture some nuances that permeate the school environment. Our proposal was to observe in what circumstances the objective conditions experienced by teachers in elementary schools I in Parnamirim-RN, tend to conflict with the provisions incorporated by them in their daily life. To put it another way, it means that it is not always the practice can reconcile Professorial what had previously been prescribed and thus widely accepted, with the way to perceive, evaluate and act for each. Although usually pass unnoticed, this disharmony is more common than you think. Proof of this are the looks directed those who fortuitously doubters fail to adapt immediately to regulations imposed by the education system (SE).

A criança com transtorno do espectro autista (TEA) e o professor: uma proposta de intervenção baseada na experiência de aprendizagem mediada (EAM)

The presence of students with Autism Spectrum Disorder (ASD) in regular schools has increased and with it, the need to develop interventional strategies that enhance their learning. One of the tools that can facilitate this process is Mediated Learning, defined as an interaction style where the teacher selects, modifies, enhances, and interprets environmental stimuli in order to promote student learning. In recent years several studies have used the Mediated Learning Experience Scale (MLE; Lidz, 1991) as a tool to assess the mediator behavior. These studies have suggested that the EAM Scale can provide important guidelines for planning educational interventions, particularly those involving students with special needs. In order to extend these findings, this study aimed to evaluate the effects of an intervention based on the Mediated Learning Experience on social / academic skills of a child with ASD, enrolled in the 4th grade of a regular elementary school. This collaborative study was held in the city of Parnamirim, state of Rio Grande do Norte, in 2014. A 9-year old boy with ASD and his teacher participated in the study. The research used a quasi-experimental A-B design (baseline and treatment) to evaluate the teacher's behavior. Qualitative procedures were also used to analyze the dyad´s responses. Teacher and student behaviors were observed in three school routines during baseline. Based on the results of this phase, a training program was designed for the teacher. Dyad behavior was analyzed again after training in the same routines. The results of this phase showed qualitative and quantitative changes in levels of teacher mediation. Additionally, data indicated that the child enhanced his social and academic skills during the intervention.

Tratamento de argila montmorilonítica para a produção de nanocompósitos poliméricos com retardo de propagação de chama

Compared to conventional composites, polymer matrix nanocomposites typically exhibit enhanced properties at a significantly lower filler volume fraction. Studies published in the literature indicate t hat the addition of nanosilicate s can increase the resistance to flame propagation in polymers. In this work, a treatment of montmorillonite (MMT) nano clay and the effect of its ad dition o n flame propagation characteristics of vinyl ester were studied. The resea rch was conducted in two stages. The first stage focused on the purification and activation of the MMT clay collected from a natural deposit to improve compatibility with the polymer matrix . Clay modification with sodium acetate was also studied to improve particle dispersion in the polymer. The second step was focused on the effect of the addition of the treated clay on nanocomposites ’ properties. Nanocomposites with clay con tents of 1, 2, 4 wt. % were processed. T he techniques for the characterization of the clay included X - ray fluorescence (XRF), X - r ay d iffraction (XRD), thermogravimetric a nalysis (TGA), d ifferential scanning c alorimetry (DSC) , s urface area (BET) and Fourier transform infrared spectroscopy (FTIR). For t he characterization of the nanocomposites , the techniques used were thermogravimetric a nalysis (TGA) , differential scanning c alorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) , scanning electron mi croscopy (SEM), transmission electron m icroscopy (TEM), and the determination of tensile strength, modulus of elasticity and resistance to flame propagation. According to the results, the purification and activation treatment with freeze - drying used in thi s work for the montmorillonite clay was efficient to promote compatibility and dispersion in the polymer matrix as evidenced by the characterization of the nanocomposite s . It was also observed that the clay modifica tion using sodium acetate did not produce any significant effect to improve compatibilization of the clay with the polymer. The addition of the treated MMT resulted in a reduction of up to 53% in the polymer flame propagation speed and did not affect the mechanical tensile strength and modulus o f elas ticity of the polymer, indicating compatibility between the clay and polymer. The effectiveness in reducing flame propagation speed peaked for nanocomposites with 2 wt. % clay, indicating that this is the optimum clay concentration for this property. T he clay treatment used in this work enables the production of vinylester matrix nanocomposites with flame - retardancy properties .

Análise do desempenho de um refrigerador doméstico funcionando com uma válvula de expansão micrométrica

Household refrigerators are equipments that represent a significant portion on the eletricity consumption of Brazilian homes. The use of these devices with low energy efficiency contributes to increase the energy consumption. The energy efficiency of a refrigerator is a function of the interaction between the coolant fluid and the components of the thermodynamic cycle. Changes in load and/or nature of the coolant may modify the condensing and/or evaporation pressures. The volumetric capacity of the compressor, the mass flow of coolant and the compression power are dependent parameters of the condensation and evaporation pressures. Thus, the expansion devices exert an importante role in the balance of these pressures, being fundamental for the better performance of the refrigeration cycle. This experimental research aims to investigate the sensitivity of the performance parameters of a household refrigerator operating with R134a and at different evaporation pressures. Therefore, a small refrigerator was instrumented with temperature, pressure sensors and other variables of interest, installed along the cooling circuit, in order to allow the thermal mapping and the evaluation of the equipment performance parameters. The variation of pressure loss in the coolant fluid resulting from the operation of the expansion valve with micrometric adjustment that modifies the evaporation temperature, influencing significantly the performance parameters of the thermodynamic refrigeration cycle.

Qualidade da água de um reservatório e do solo da zona ripária sob diferentes usos na região semiárida do Rio Grande do Norte

Reservoirs are artificial ecosystems intermediate between rivers and lakes widely used in the Brazilian semiarid region as a way to provide water supply due to the said region’s water scarcity. The use of water from these supply sources for multiple uses, along with occupation and utilization of its riparian zone without proper management, directly influences the increased nutrient flow into aquatic environments, there with contributing to the acceleration of eutrophication. The semi-arid region is characterized by peculiar weather conditions, such as severe evaporation, high temperatures with little variation throughout the year and long water residence time, making it susceptible to prolonged drought occurrence, which tends to concentrate the nutrients in reservoirs, which favors the development of eutrophic conditions. Moreover, it is common soil use and occupation by carrying out activities with potential environmental impact on natural resources such as agriculture, livestock farming and lack of sanitation. The aim of this study is both to evaluate the water quality of the Cruzeta Reservoir, located in the semiarid region of Rio Grande do Norte, during a prolonged drought period, and assess the quality of its riparian zone soil under different uses, by monitoring physical-chemical variables. Along the prolonged drought, high levels of turbidity, suspended solids, nutrients and chlorophyll a were verified as present, therefore featuring low water quality. In the riparian zone of Cruzeta Reservoir, the areas under use of agriculture and livestock farming appeared as one of the main diffuse sources of nutrients to the said reservoir, featuring the highest levels of phosphorus and nitrogen in the soil, originated from decomposition of animal excreta and from the use of fertilizers, creating a tendency to increased eutrophication of such water supply source. The indicators of water and soil quality are useful for monitoring and evaluating the conservation status of natural resources, allowing the control and mitigation of the reservoir eutrophication process. This study confirmed the hypothesis that the reduction of water level, resulting from prolonged drought event, aggravates the symptoms of eutrophication; and also that using the soil under severalways modifies the physic chemical properties of the soil, having livestock farming and agriculture as the usages with greatest potential towards yielding P and N to the aquatic environment.

Efeitos imediatos da plataforma vibratória no desempenho neuromuscular do quadríceps femoral, após reconstrução do LCA: ensaio controlado, randomizado e cego

Objective: to investigate the immediate effect of the vibrating platform on the neuromuscular performance of the quadriceps femoris and on the postural oscillation of subjects submitted to Anterior Cruciate Ligament (ACL) reconstruction. Materials and methods: this study is a randomized and blind clinical trial. Forty-four male volunteers (average age of 27,4 ±6,2 IMC of 26,85± 3,8 Kg/m² and post surgery timeframe of 17± 1,4 weeks) were randomized into two groups: OFF platform (n=22, protocol of exercise over the vibrating platform off) and ON platform (n=22 protocol of exercise over the vibrating platform on, 50Hz frequency and 4mm of amplitude). All volunteers were submitted to assessment the isokinetic evaluation of the quadriceps femoris (isometric and isokinetic at 60°/s) and of the electromyography activity of the muscles Vasto Lateralis (VL) and Vasto Medialis (VM), besides the postural oscillation (baropodometry) in two distinct moments: before and immediately after the intervention protocol. The data was analyzed through the SPSS 20.0 software, with a 5% significance level. To verify the homogeneity of the groups it was used an ANOVA one way, and a ANOVA mixed model to compare the intra and inter groups. Results: it was observed differences between the pre and the post, to latero lateral velocity, isometric torque peak and total work in comparison with intragroup. However, it wasn’t verified any difference in comparing the intergroup in the preevaluation and in the post-evaluation protocol over the vibrating platform. Conclusion: the use of the vibrating platform doesn’t change as an immediate manner the isokinetic performance of the quadriceps femoris, the electromyography activity of the VL and the VM, also doesn’t interfere with the postural oscillation of individuals that were submitted to the ACL reconstruction.

Hepatite C crônica em serviço de referência no nordeste do Brasil: um estudo retrospectivo de dezoito anos de acompanhamento

Chronic Hepatitis C is the leading cause of chronic liver disease in advanced final stage of hepatocellular carcinoma (HCC) and of death related to liver disease. Evolves progressively in time 20-30 years. Evolutionary rates vary depending on factors virus, host and behavior. This study evaluated the impact of hepatitis C on the lives of patients treated at a referral service in Hepatology of the University Hospital Onofre Lopes - Liver Study Group - from May 1995 to December 2013. A retrospective evaluation was performed on 10,304 records, in order to build a cohort of patients with hepatitis C, in which all individuals had their diagnosis confirmed by gold standard molecular biological test. Data were obtained directly from patient charts and recorded in an Excel spreadsheet, previously built, following an elaborate encoding with the study variables, which constitute individual data and prognostic factors defined in the literature in the progression of chronic hepatitis C. The Research Ethics Committee approved the project. The results were statistically analyzed with the Chi-square test and Fisher's exact used to verify the association between variable for the multivariate analysis, we used the Binomial Logistic regression method. For both tests, it was assumed significance p < 0.05 and 95%. The results showed that the prevalence of chronic hepatitis C in NEF was 4.96 %. The prevalence of cirrhosis due to hepatitis C was 13.7%. The prevalence of diabetes in patients with Hepatitis C was 8.78 % and diabetes in cirrhotic patients with hepatitis C 38.0 %. The prevalence of HCC was 5.45%. The clinical follow-up discontinuation rates were 67.5 %. The mortality in confirmed cases without cirrhosis was 4.10% and 32.1% in cirrhotic patients. The factors associated with the development of cirrhosis were genotype 1 (p = 0.0015) and bilirubin > 1.3 mg % (p = 0.0017). Factors associated with mortality were age over 35 years, abandon treatment, diabetes, insulin use, AST> 60 IU, ALT> 60 IU, high total bilirubin, extended TAP, INR high, low albumin, treatment withdrawal, cirrhosis and hepatocarcinoma. The occurrence of diabetes mellitus increased mortality of patients with hepatitis C in 6 times. Variables associated with the diagnosis of cirrhosis by us were blood donor (odds ratio 0.24, p = 0.044) and professional athlete (odds ratio 0.18, p = 0.35). It is reasonable to consider a revaluation in screening models for CHC currently proposed. The condition of cirrhosis and diabetes modifies the clinical course of patients with chronical hepatitis C, making it a disease more mortality. However, being a blood donor or professional athlete is a protective factor that reduces the risk of cirrhosis, independent of alcohol consumption. Public policies to better efficient access, hosting and resolution are needed for this population.

Realidade ou ficção? A influência da autopercepção como parceiro romântico e da autoestima na escolha e preferência de parceiros românticos

In general, men and women look for characteristics that can indicate improvement of their reproductive success in their romantic partners. However, partner choice is not only based on what the individual want in a partner, but he/she also takes into consideration how they perceive themselves in a determined environment, in a way that self-perception can change according to the context where the individual is inserted in. Besides the environment, self-esteem can be a factor that modifies romantic partner preferences and the way that people choose these partners for being able to influence how people evaluate themselves. Most of the studies that originate today’s universal standards in the study of romantic partner were conducted with undergraduate students, which may limit the coverage of the conclusions for contemplating people of the same educational level and probably also socioeconomic status (SES). The present research, held in Brazil, where the social inequality rate is high, and part in Canada, country with low social inequality, had as goal verifying romantic partners preferences and choices and self-evaluation as romantic partners in different educational level and SES. Men, mainly of low SES, tend to prioritize social status when looking for a romantic partner while the universal pattern is the preference for physical attractiveness, and women of low SES seem to be aware of this preference when expressing that social status is important for their self-perception. In addition, the results corroborate the influence of the context, selfesteem, and SES in the self-perception as a romantic partner, though the latter two appear to modulate how the is the influence of the context on participants’ perception. Moreover, this research also indicated that the preferences appear to represent the choices for the most important characteristics for each sex, being the other characteristics probably modulated by the quantity of available participants in the environment.

Estudo da adesão de pinos endodônticos modificados superficialmente por plasma de oxigênio

The work presents the effect of plasma treatment when applied in fibers or carbon/glass posts in the adhesion fiber/resin and posts/cement. This has for objective the modification of the surface of the fibers, as well as the wettability of the posts, seeking the improvement of the adhesion and of the connection fiber/resin in the processing of polymeric composites reinforced with the same ones. 120 posts (Reforpost) were used and 30 meters of fibers of carbon and of glass (Fibrex), of the company Angelus. The samples were divided in three groups of 40 specimens: GROUP I - 20 posts of glass fiber and 20 of carbon without treatment to it shapes, GROUP II -20 posts of glass fiber and 20 of carbon treated to it shapes in the surface and GROUP III - 20 posts of glass fiber and 20 of carbon make with fibers in natura after plasma treatment. The plasma treatment was accomplished with oxygen and with temperature in the camera fixed at 200°C, for one hour of exhibition. The posts and the fibers were characterized before and after the treatment. The wettability was measure by pendent drop method, and interface fiber/resin and posts/cement were observed by optical and electronic microscopy. It was observed that both wettability and texture were increased with plasma treatment

Efeitos do tratamento superficial da sílica ativa com soluções de ácidos nítrico e fosfórico em propriedades do concreto

The addition of active silica potentially improves the quality of concrete due to its high reactivity and pore refinement effect. The reactivity of silica is likely related to its charge density. Variations in surface charge alter the reactivity of the material consequently affecting the properties of concrete. The present study aimed at investigating variations in the charge density of silica as a function of acid treatments using nitric or phosphoric acid and different pH values (2.0, 4.0 and 6.0). Effects on concrete properties including slump, mechanical strength, permeability and chloride corrosion were evaluated. To that end, a statistical analysis was carried out and empirical models that correlate studied parameters (pH, acid and cement) with concrete properties were established. The quality of the models was tested by variance analysis. The results revealed that the addition of silica was efficiency in improving the properties of concrete, especially the electrochemical parameters. The addition of silica treated using nitric acid at pH = 4.0 displayed the best cement performance including highest strength, reduced permeability and lowest corrosion current