O e-consumidor à luz da teoria do valor percebido: um estudo sobre a aceitação ao mobile commerce

With the advancement of technologies and devices such as smartphones that allow connection to the internet, other forms of online consumption have emerged. E-commerce, once defined as a computer-mediated trading market, has turned into mobile commerce, or m-commerce, an abbreviated form of the term. However, not all consumers are willing to adopt this new format to consume products and services. The consumer tends to have the intention to consume products and services in which he or she perceives added value in the exchange process. Therefore, this study sought to analyze the antecedent factors of the perceived value and how these factors influence the intention to purchase m-commerce via cell phones. In methodological terms, the data collection was performed through the application of online questionnaires with the help of the Google Forms tool, with 452 of the questionnaires being validated. Constructs from Theories and Models of acceptance of technology are viewed in this study as the prism through which to analyze the acceptance of m-commerce by consumers. Moreover, they are the predictors for the perceived value. The results showed that the constructs perceived utility, perceived ease of use, relative advantage, compatibility, pleasure, and perceived security have a direct influence on the perceived value.Keywords: smartphones, e-consumer, m-commerce, perceived value.Com o avanço de tecnologias e dispositivos como smartphones que permitem conexão com a internet, outras formas de consumir online emergiram. O e-commerce, que antes era definido como um mercado de trocas mediado por computador, transforma-se no mobile commerce, ou m-commerce, uma forma abreviada do termo. Todavia, nem todos os consumidores estão dispostos a adotarem esse novo formato de consumir produtos e serviços. O consumidor tende a ter a intenção em consumir produtos e serviços nos quais ele percebe valor agregado na relação de troca. Nessa direção, este estudo buscou analisar os fatores antecedentes do valor percebido, e como esse influencia a intenção de compra no m-commerce por intermédio de telefones celulares. Em termos metodológicos, a coleta de dados se deu por meio da aplicação de questionários online com o auxílio da ferramenta Google Forms, sendo validados 452 deles. Constructos de teorias e modelos de aceitação de tecnologia são vistos neste estudo como o prisma através do qual se analisa a aceitação do m-commerce pelos consumidores. Além disso, eles são os preditores do valor percebido. Os resultados mostraram que os construtos utilidade percebida, facilidade de uso percebida, vantagem relativa, compatibilidade, prazer e segurança percebida têm influência direta sobre o valor percebido.Palavras-chave: smartphones, e-consumidor, m-commerce, valor percebido

A new gravitational N-body simulation algorithm for investigation of cosmological chaotic advection

Recently alternative approaches in cosmology seeks to explain the nature of dark matter as a direct result of the non-linear spacetime curvature due to different types of deformation potentials. In this context, a key test for this hypothesis is to examine the effects of deformation on the evolution of large scales structures. An important requirement for the fine analysis of this pure gravitational signature (without dark matter elements) is to characterize the position of a galaxy during its trajectory to the gravitational collapse of super clusters at low redshifts. In this context, each element in an gravitational N-body simulation behaves as a tracer of collapse governed by the process known as chaotic advection (or lagrangian turbulence). In order to develop a detailed study of this new approach we develop the COsmic LAgrangian TUrbulence Simulator (COLATUS) to perform gravitational N-body simulations based on Compute Unified Device Architecture (CUDA) for graphics processing units (GPUs). In this paper we report the first robust results obtained from COLATUS.Comment: Proceedings of Sixth International School on Field Theory and Gravitation-2012 - by American Institute of Physic

Comparing Mixed & Integer Programming vs. Constraint Programming by solving Job-Shop Scheduling Problems

Scheduling is a key factor for operations management as well as for business success. From industrial Job-shop Scheduling problems (JSSP), many optimization challenges have emerged since de 1960s when improvements have been continuously required such as bottlenecks allocation, lead-time reductions and reducing response time to requests.  With this in perspective, this work aims to discuss 3 different optimization models for minimizing Makespan. Those 3 models were applied on 17 classical problems of examples JSSP and produced different outputs.  The first model resorts on Mixed and Integer Programming (MIP) and it resulted on optimizing 60% of the studied problems. The other models were based on Constraint Programming (CP) and approached the problem in two different ways: a) model CP1 is a standard IBM algorithm whereof restrictions have an interval structure that fail to solve 53% of the proposed instances, b) Model CP-2 approaches the problem with disjunctive constraints and optimized 88% of the instances. In this work, each model is individually analyzed and then compared considering: i) Optimization success performance, ii) Computational processing time, iii) Greatest Resource Utilization and, iv) Minimum Work-in-process Inventory. Results demonstrated that CP-2 presented best results on criteria i and ii, but MIP was superior on criteria iii and iv and those findings are discussed at the final section of this work

A abordagem histórico-investigativa no ensino de Ciências

A abordagem Histórico-Investigativa (HI) vem sendo construída ao longo das duas últimas décadas no contexto da busca por caminhos para incentivar motivação, engajamento e argumentação dos alunos em sala de aula. A HI destaca-se por propiciar competências relevantes ao fazer científico, além de tornar os alunos mais ativos e participativos do processo de aprendizagem e contextualizar os conhecimentos escolares. Essa abordagem caracteriza-se pelo uso de atividades experimentais de cunho investigativo, pautadas por episódios históricos, centradas nos alunos e orientadas pelo professor, de modo a criar situações de ensino e aprendizagem que propiciem a reflexão sobre conteúdos específicos da ciência e conteúdos metacientíficos, a prática experimental e a argumentação. Este artigo discute as bases pedagógicas e epistemológicas, objetivos e contribuições da abordagem histórico-investigativa aoEnsino de Ciências.The Historical-Investigative approach (HI) has been built over the last two decades in the context of the search for strategies to encourage students’ motivation, engagement, and argumentation in the classroom. HI provides relevant scientific skills, makes students more active and participatory in the learning process, and contextualizes school knowledge. This approach is characterized by the use of investigative experimental activities, guided by cases from the history of Science. The activities are student- -centered and teacher-oriented, and aim to create teaching and learning situations that foster reflection on specific scientific and meta-scientific contents, experimental practice, and argumentation. This paper discusses the pedagogical and epistemological foundations, objectives and contributions of the historical-investigative approach to Science teaching

Comparação da fauna de formigas de serapilheira entre área de floresta atlântica secundária e plantação adjacente de pinus no sudeste do Brasil

We investigated the influence of Pinus afforestation on the structure of leaf-litter ant communities in the southeastern Brazilian Atlantic Forest, studying an old secondary forest and a nearly 30 year-old never managed Pinus elliottii reforested area. A total of 12,826 individual ants distributed among 95 species and 32 genera were obtained from 50 1 m² samples/ habitat. Of these, 60 species were recorded in the pine plantation and 82 in the area of Atlantic forest; almost 50% of the species found in the secondary forest area were also present in the pine plantation. The number of species per sample was significantly higher in the secondary forest than in the pine plantation. Forest-adapted taxa are the most responsible for ant species richness differences between areas, and the pine plantation is richer in species classified as soil or litter omnivorous-dominants. The specialized ant predators registered in the pine plantation, as seven Dacetini, two Basiceros, two Attini and two Discothyrea, belong to widely distributed species. The NMDS (non-metric multidimensional scaling) ordination also suggested strong differences in similarity among samples of the two areas. Furthermore, this analysis indicated higher sample heterogeneity in the secondary forest, with two clusters of species, while in the pine plantation the species belong to a single cluster. We applied the ant mosaic hypothesis to explain the distribution of the leaf-litter fauna and spatial autocorrelation tests among samples. We argue that the results are likely related to differences in quality and distribution of the leaf-litter between the pine plantation and the secondary area.A influência do reflorestamento com Pinus na estrutura da fauna de formigas de serapilheira foi investigada, estudando uma floresta Atlântica secundária inalterada há 30 anos e uma área reflorestada com Pinus elliottii no Sudeste do Brasil. Em 50 amostras de 1 m² tomadas em cada área, foram coletados 12.826 indivíduos, distribuídos em 95 espécies e 32 gêneros de formigas. Foram identificadas 60 espécies na área reflorestada com Pinus e 82 espécies na área de floresta secundária; aproximadamente 50% das espécies foram registradas nas duas áreas. A mediana do número de espécies por amostra foi maior na floresta secundária. Táxons com biologia especializada são responsáveis por grande parte das diferenças de composição de fauna, sendo a área de reflorestamento com Pinus mais rica em espécies onívoras e dominantes. Predadoras especializadas registradas na área de Pinus, como sete espécies de Dacetini, duas Basiceros, duas Attini e duas Discothyrea, têm ampla distribuição na Floresta Atlântica. A ordenação das amostras com o escalonamento multidimensional não-métrico (NMDS) indicou grande diferença na similaridade entre as amostras das áreas. Adicionalmente, essa análise sugere maior heterogeneidade na composição das amostras da floresta secundária, identificando dois agrupamentos de espécies, enquanto a área de Pinus apresenta um agrupamento apenas. Para investigar quais fatores podem explicar a heterogeneidade observada, testes de co-ocorrência e de autocorrelação espacial foram aplicados entre amostras de cada área. Nossa conclusão é que as diferenças observadas devem estar relacionadas com diferenças na qualidade e distribuição da serapilheira entre as áreas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)UMC - Fundação de Amparo ao Ensino e Pesquis

O e-consumidor à luz da teoria do valor percebido: um estudo sobre a aceitação ao mobile commerce

With the advancement of technologies and devices such as smartphones that allow connection to the internet, other forms of online consumption have emerged. E-commerce, once defined as a computer-mediated trading market, has turned into mobile commerce, or m-commerce, an abbreviated form of the term. However, not all consumers are willing to adopt this new format to consume products and services. The consumer tends to have the intention to consume products and services in which he or she perceives added value in the exchange process. Therefore, this study sought to analyze the antecedent factors of the perceived value and how these factors influence the intention to purchase m-commerce via cell phones. In methodological terms, the data collection was performed through the application of online questionnaires with the help of the Google Forms tool, with 452 of the questionnaires being validated. Constructs from Theories and Models of acceptance of technology are viewed in this study as the prism through which to analyze the acceptance of m-commerce by consumers. Moreover, they are the predictors for the perceived value. The results showed that the constructs perceived utility, perceived ease of use, relative advantage, compatibility, pleasure, and perceived security have a direct influence on the perceived value.Keywords: smartphones, e-consumer, m-commerce, perceived value.Com o avanço de tecnologias e dispositivos como smartphones que permitem conexão com a internet, outras formas de consumir online emergiram. O e-commerce, que antes era definido como um mercado de trocas mediado por computador, transforma-se no mobile commerce, ou m-commerce, uma forma abreviada do termo. Todavia, nem todos os consumidores estão dispostos a adotarem esse novo formato de consumir produtos e serviços. O consumidor tende a ter a intenção em consumir produtos e serviços nos quais ele percebe valor agregado na relação de troca. Nessa direção, este estudo buscou analisar os fatores antecedentes do valor percebido, e como esse influencia a intenção de compra no m-commerce por intermédio de telefones celulares. Em termos metodológicos, a coleta de dados se deu por meio da aplicação de questionários online com o auxílio da ferramenta Google Forms, sendo validados 452 deles. Constructos de teorias e modelos de aceitação de tecnologia são vistos neste estudo como o prisma através do qual se analisa a aceitação do m-commerce pelos consumidores. Além disso, eles são os preditores do valor percebido. Os resultados mostraram que os construtos utilidade percebida, facilidade de uso percebida, vantagem relativa, compatibilidade, prazer e segurança percebida têm influência direta sobre o valor percebido.Palavras-chave: smartphones, e-consumidor, m-commerce, valor percebido

Quantification and distribution of vibrio species in water from an estuary in Ceará-Brazil impacted by shrimp farming

Vibrios were quantified and their distribution determined for the estuary of the Coreaú river, in Northeastern Brazil, based on 24 water samples collected between June and October 2005. The most probable number of vibrios per 100 mL ranged from 230 x 10³ to 240 x 10(11). The pH value was the environmental factor most strongly associated with the abundance of vibrios. Sixty-two vibrio strains were isolated belonging to 15 species (6 of which observed in June-September and 8 in October). The most frequently isolated species were V. parahaemolyticus and V. cholerae.Foram realizadas análises concernentes à quantificação e distribuição de Vibrio em 24 amostras de água do estuário do Rio Coreaú (CE) no período de junho a novembro de 2005. O Número Mais Provável (NMP/100 mL) de Vibrio oscilou de 230 x 10³ a 240 x 10(11). O pH foi o fator ambiental que mais favoreceu ao aumento da microbiota de Vibrio. Foram isoladas 62 cepas de Vibrio, sendo observada uma distribuição de sete espécies nos meses de junho a setembro, e oito espécies no mês de outubro. As espécies mais freqüentes nos isolamentos foram V. parahaemolyticus e V. cholerae

Lipopolysaccharide and lipotheicoic acid differentially modulate epididymal cytokine and chemokine profiles and sperm parameters in experimental acute epididymitis

Bacterial infections are the most prevalent etiological factors of epididymitis, a commonly diagnosed inflammatory disease in the investigation of male infertility factors. The influence of early pathogenic mechanisms at play during bacterial epididymitis on reproductive outcomes is little understood. We report here that experimental epididymitis induced in rats by Gram-negative (LPS) and Gram-positive (LTA) bacterial products resulted in differential patterns of acute inflammation in the cauda epididymis. LPS elicited a strong inflammatory reaction, as reflected by upregulation of levels of mRNA for seven inflammatory mediators (Il1b, Tnf, Il6, Ifng, Il10, Nos2 and Nfkbia), and tissue concentration of six cytokines/chemokines (IL1A, IL1B, IL6, IL10, CXCL2 and CCL2) within the first 24 h post-treatment. Conversely, LTA induced downregulation of one (Nfkbia) and upregulation of six (Il1b, Il6, Nos2, Il4 Il10 and Ptgs1) inflammatory gene transcripts, whereas increased the tissue concentration of three cytokines/chemokines (IL10, CXCL2 and CCL2). The stronger acute inflammatory response induced by LPS correlated with a reduction of epididymal sperm count and transit time that occurred at 1, 7, and 15 days post-treatment. Our study provides evidence that early epididymal inflammatory signaling events to bacterial activators of innate immunity may contribute to the detrimental effects of epididymitis upon male fertility.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)CNPqSao Paulo Research Foundation (FAPESP)Pro-Reitoria de Pesquisa/UNESPUniv Fed Sao Paulo, Escola Paulista Med, Sect Expt Endocrinol, Dept Pharmacol, BR-04044020 Sao Paulo, SP, BrazilUniv Estadual Paulista, Dept Pharmacol, Inst Biosci Botucatu, Botucatu, SP, BrazilSci & Innovat Ctr Androl, Androsci, BR-03178200 Sao Paulo, SP, BrazilUniv Sao Paulo, Med Sch, Hosp Clin, Reprod Toxicol Unity,Dept Pathol, BR-01246903 Sao Paulo, SP, BrazilUniv Sao Paulo, Med Sch, Hosp Clin, Div Urol, BR-01246903 Sao Paulo, SP, BrazilState Univ Centro Oeste, Dept Pharm, BR-85040080 Guarapuava, PR, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Sect Expt Endocrinol, Dept Pharmacol, BR-04044020 Sao Paulo, SP, Brazil(CNPq)/CSF/BJT: 401718/2012-3CNPq: 479546/2013-4, 455450/2014-5, 308349/2010-5FAPESP: 2010/52711-0, 2015/08227-0Pro-Reitoria de Pesquisa/UNESP: 557Web of Scienc

Differential regulation of PGC-1α expression in rat liver and skeletal muscle in response to voluntary running

<p>Abstract</p> <p>Background</p> <p>The beneficial actions of exercise training on lipid, glucose and energy metabolism and insulin sensitivity appear to be in part mediated by PGC-1α. Previous studies have shown that spontaneously exercised rats show at rest enhanced responsiveness to exogenous insulin, lower plasma insulin levels and increased skeletal muscle insulin sensitivity. This study was initiated to examine the functional interaction between exercise-induced modulation of skeletal muscle and liver PGC-1α protein expression, whole body insulin sensitivity, and circulating FFA levels as a measure of whole body fatty acid (lipid) metabolism.</p> <p>Methods</p> <p>Two groups of male Wistar rats (2 Mo of age, 188.82 ± 2.77 g BW) were used in this study. One group consisted of control rats placed in standard laboratory cages. Exercising rats were housed individually in cages equipped with running wheels and allowed to run at their own pace for 5 weeks. At the end of exercise training, insulin sensitivity was evaluated by comparing steady-state plasma glucose (SSPG) concentrations at constant plasma insulin levels attained during the continuous infusion of glucose and insulin to each experimental group. Subsequently, soleus and plantaris muscle and liver samples were collected and quantified for PGC-1α protein expression by Western blotting. Collected blood samples were analyzed for glucose, insulin and FFA concentrations.</p> <p>Results</p> <p>Rats housed in the exercise wheel cages demonstrated almost linear increases in running activity with advancing time reaching to maximum value around 4 weeks. On an average, the rats ran a mean (Mean ± SE) of 4.102 ± 0.747 km/day and consumed significantly more food as compared to sedentary controls (<it>P </it>< 0.001) in order to meet their increased caloric requirement. Mean plasma insulin (<it>P </it>< 0.001) and FFA (<it>P </it>< 0.006) concentrations were lower in the exercise-trained rats as compared to sedentary controls. Mean steady state plasma insulin (SSPI) and glucose (SSPG) concentrations were not significantly different in sedentary control rats as compared to exercise-trained animals. Plantaris PGC-1α protein expression increased significantly from a 1.11 ± 0.12 in the sedentary rats to 1.74 ± 0.09 in exercising rats (<it>P </it>< 0.001). However, exercise had no effect on PGC-1α protein content in either soleus muscle or liver tissue. These results indicate that exercise training selectively up regulates the PGC-1α protein expression in high-oxidative fast skeletal muscle type such as plantaris muscle.</p> <p>Conclusion</p> <p>These data suggest that PGC-1α most likely plays a restricted role in exercise-mediated improvements in insulin resistance (sensitivity) and lowering of circulating FFA levels.</p