Strategies employed by e-commerce firms in Portugal : an empirical investigation

A survey integrating different theoretical views of value creation was developed, then sent to Portuguese e-ommerce firms to assess the underlying dimensions and the most important characteristics of their e-Commerce strategies. The survey was sent to 188 firms in 2007 and repeated in 2010 to validate the results, obtaining a total sample of 62 e-Commerce firms. Through factorial analysis, three e-Commerce strategy dimensions were identified: one relates to differentiation via marketing based on reputation and brand identification, in which advertising and innovation in marketing techniques and methods are important; a second differentiation dimension focuses on product development and is supported by technical capabilities; and a cost leadership dimension which uses strategic networks to obtain economies of scale and scope, and exploits technological advancements to reduce transaction costs

Estratégias de E-Commerce e o seu Impacto na Performance Empresarial: uma Abordagem pelo Processo de Criação de Valor

Tese de doutoramento em Gestão de Empresas, na especialidade de Estratégia, apresentada à Faculdade de Economia da Universidade de CoimbraA identificação das estratégias de e-commerce e a avaliação do seu impacto na performance empresarial foram os principais objectivos desta investigação. Foi elaborado um questionário integrando várias teorias de criação de valor, que foi enviado a empresas portuguesas de e-commerce, de forma a determinar as dimensões subjacentes às suas estratégias de comércio electrónico, bem como as principais características das mesmas. O questionário foi enviado a 188 empresas em 2007, e replicado em 2010 para validar os resultados, tendo sido possível obter uma amostra de 62 empresas. Através da análise factorial foram evidenciadas três dimensões estratégicas: uma dimensão relacionada com uma estratégia de diferenciação via marketing, baseada na reputação e na marca, na qual a publicidade e a inovação nas técnicas e métodos de marketing são importantes; uma segunda dimensão correspondente a uma estratégia de diferenciação via inovação de produtos, suportada por capacidades técnicas; e por último, uma dimensão associada a uma estratégia de liderança pelos custos, na qual se procura obter economias de escala e de âmbito através da utilização de redes estratégicas, bem como a redução dos custos de transacção por via da exploração de avanços tecnológicos. Os resultados da análise de clusters permitiram identificar dois grupos estratégicos, com uma orientação estratégica semelhante, mas com diferentes graus de intensidade na sua implementação. O grupo que atribui maior importância às dimensões atrás mencionadas, apresentou uma melhor performance. A análise de regressão evidencia que só os factores associados à diferenciação têm impacto na performance, no contexto dos mercados virtuais, quando se tem em conta a influência da orientação estratégica, sendo o marketing e a inovação os dois principais determinantes da variabilidade observada na performance empresarial. A importância da diferenciação sugere que as empresas de e-commerce devem ter um posicionamento estratégico, de forma a conseguirem uma vantagem competitiva, e que a maior parte das teorias de criação de valor desenhadas para o mundo físico se mantêm válidas, embora seja necessária a sua integração para explicar a criação de valor neste contexto. No final do dia o e-commerce é só commerce, apesar das características específicas dos mercados virtuais permitirem diferentes combinações de recursos, potenciando a inovação e criando novas oportunidades.The identification of e-commerce strategies and their impact on corporate performance was the main purpose of the investigation. A survey integrating different theoretical views of value creation was developed, then sent to Portuguese e-commerce firms to assess the underlying dimensions and the most important characteristics of their e-commerce strategies. The survey was sent to 188 firms in 2007 and repeated in 2010 to validate the results, obtaining a total sample of 62 ecommerce firms. Through factorial analysis, three e-commerce strategy dimensions were identified: one relates to differentiation via marketing, based on reputation and brand identification, in which advertising and innovation in marketing techniques and methods are important; a second differentiation dimension focuses on product innovation and is supported by technical capabilities; and a cost leadership dimension which uses strategic networks to obtain economies of scale and scope, and exploits technological advancements to reduce transaction costs. The results of the clustering analysis identified two strategic groups with similar strategic orientation, which corresponds to a differentiation strategy. However, the group that gives more importance to the strategic dimensions highlighted above shows better performance. Moreover, the regression analysis reveals that only the differentiation factors impact on performance in the context of virtual markets, being marketing and innovation the two main determinants of e-commerce companies’ performance, when considering firms’ strategic orientation. The importance given to differentiation dimensions suggest that e-commerce firms should have a strategic positioning in order to achieve a competitive advantage, and most of the theories of value creation built for the physical world remain valid, although an integration of different theories is needed to explain value creation in the context of virtual markets. At the end of the day, e-commerce is just commerce, even though virtual markets have specific characteristics which allow for different combinations of resources, thus boosting innovation and creating new opportunities

An Elephant in the Room: Using Sampling for Detecting Heavy-Hitters in Programmable Switches

The ability to detect elephant flows in the forwarding device itself, i.e., a switch, facilitates the deployment of new advanced applications such as load-balancing, per-flow QoS management, etc. Sketches and Space Saving summarization techniques are used for elephant flow detection. However, their memory and computing requirements force the cooperation of an external controller device, due to the scarce resources of current programmable switches. To overcome this limitation, we adapt Sketch and Space Saving elephant flow detection techniques to operate with instant notification and sampled traffic. We evaluate the performance of the resulting techniques with three real traffic traces. The use of sampling allows the identification of a large share of the total traffic corresponding to the elephant flows with a low memory footprint and a reduction of the computing requirements in two orders of magnitude compared to unsampled versions. In turn, we observe a slight increase in the number of false positives and the number of flow notifications.The work of Alberto García-Martínez and Marcelo Bagnulo was supported by the TRUE5G Project ('Evolución hacia redes y servicios auto-gestionados para el 5G del futuro') by the Spanish National Research Agency under Grant PID2019-108713RB-C52/AEI/10.13039/501100011033

Bartolomeu: An SDN rebalancing system across multiple interdomain paths

Bartolomeu is a solution to enable stub networks to perform adaptive egress traffic load balancing across multiple interdomain routes by spreading the traffic across available paths according to a passive measurement of their performance. It defines a BGP-SDN architecture that increases the number of BGP routes that can be used by stub networks. Bartolomeu measures the available capacity of each path to any destination prefix, and allocates to each path a number of large flows that is proportional to its capacity. This strategy reduces the mean sojourn time, i.e., mean time to flow completion, compared to state-of-the-art traffic balancing techniques as ECMP. We develop a mathematical model to compute this time and compare with ECMP and single path (fast path) selection. An analysis of the traffic traces of two content providers was performed to ensure that our solution is deployable. An experiment with traffic exchange over the Internet is used to show that Bartolomeu can provide gains with real interfering traffic. A discrete-event simulator fed with the traces captured is used to asses Bartolomeu's gains with prefixes with different number of flows, and flows with different sizes and arrival time. We observe in this experiment that Bartolomeu can reduce the sojourn time, compared to ECMP, by half when path rates differ in a factor of 3, or to a sixth when path rates differ in a factor of 10. We compute the maximum number of per-flow entries and the maximum entry change request rate to show that the resources required fit in with the specifications of the current generation of SDN switches.The work of Pedro Rodrigues Torres-Jr. was partially supported by the Fundación Carolina, program Mobilidad SEGIB 2019. The work of Alberto García-Martínez was supported by the 5G-TRANSFORMER project, H2020-761536. The work of and Marcelo Bagnulo was supported in part by the 5G-TRANSFORMER project, and by the Spanish Ministry of Economy and Competitiveness under 5GCity project, TEC2016-76795-C6-3-R

Pulmonary changes on HRCT scans in nonsmoking females with COPD due to wood smoke exposure

OBJECTIVE: To identify and characterize alterations seen on HRCT scans in nonsmoking females with COPD due to wood smoke exposure. METHODS: We evaluated 42 nonsmoking females diagnosed with wood smokerelated COPD and 31 nonsmoking controls with no history of wood smoke exposure or pulmonary disease. The participants completed a questionnaire regarding demographic data, symptoms, and environmental exposure. All of the participants underwent spirometry and HRCT of the chest. The COPD and control groups were adjusted for age (23 patients each). RESULTS: Most of the patients in the study group were diagnosed with mild to moderate COPD (83.3%). The most common findings on HRCT scans in the COPD group were bronchial wall thickening, bronchiectasis, mosaic perfusion pattern, parenchymal bands, tree-in-bud pattern, and laminar atelectasis (p < 0.001 vs. the control group for all). The alterations were generally mild and not extensive. There was a positive association between bronchial wall thickening and hour-years of wood smoke exposure. Centrilobular emphysema was uncommon, and its occurrence did not differ between the groups (p = 0.232). CONCLUSIONS: Wood smoke exposure causes predominantly bronchial changes, which can be detected by HRCT, even in patients with mild COPD.OBJETIVO: Identificar e caracterizar alterações na TCAR de tórax em mulheres com DPOC causada por exposiçãoà fumaça da combustão de lenha. MÉTODOS: Foram selecionadas 42 pacientes com DPOC relacionada à exposição à fumaça de lenha, não fumantes, e 31 mulheres não fumantes e sem história de exposição à fumaça de lenha ou de doença pulmonar. Empregou-se um questionário para a obtenção de dados demográficos e informações sobre sintomas e exposições ambientais. Todas as participantes realizaram espirometria e TCAR de tórax. Os grupos DPOC e controle foram ajustados por idade, com 23 pacientes cada. RESULTADOS: A maioria das pacientes do grupo de estudo apresentava DPOC de leve a moderado (83,3%). Os achados de TCAR mais frequentes no grupo DPOC foram espessamento das paredes brônquicas, bronquiectasias, perfusão em mosaico, bandas parenquimatosas, padrão de árvore em brotamento e atelectasias laminares (p < 0,001 para todos na comparação com o grupo controle). As alterações, em geral, foram leves e de pequena extensão. Houve uma associação positiva entre espessamento das paredes brônquicas e duração da exposição à fumaça de lenha em horas-ano. O achado de enfisema centrolobular foi infrequente e não diferiu entre os grupos (p = 0,232). CONCLUSÕES: A exposição à fumaça de lenha provoca alterações predominantemente brônquicas, que podem ser detectadas por TCAR, mesmo nos casos de DPOC leve.Universidade Federal de Goiás Faculdade de MedicinaUniversidade Federal de Goiás Faculdade de EnfermagemUniversidade Federal de Goiás Faculdade de Medicina Hospital das ClínicasUniversidade Federal de Goiás Faculdade de Medicina Departamento de Imagenologia e PatologiaClínica Multimagem DiagnósticosUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Psicologia Social Comunitária e Agroecologia: uma experiência de formação no contexto amazônico

Neste artigo, temos por objetivo apresentar e discutir uma experiência da disciplina Psicologia Social Comunitária, no segundo semestre de 2018, com um grupo de agricultores de alimentos orgânicos da zona rural do município de Iranduba/AM, que segue os princípios agroecológicos. Descrevemos e discutimos a elaboração do Plano de Ação nas seguintes etapas: familiarização com os agricultores em seu cotidiano; levantamento dos problemas e necessidades; elaboração das estratégias de ação e sua colocação em prática; avaliação final. Concluímos que a aproximação com os agricultores nos trouxe valiosa bagagem para a atuação profissional por: atuarmos em um contexto rural; agirmos como parceiros, em vez de termos apenas uma escuta qualificada; ampliarmos nossas consciências sobre a realidade local amazônica, e não meramente a deles; percebermos que a alimentação e escolha de produtos orgânicos é um ato político; aproximarmo-nos da Agroecologia e de sua proposta de transformação da sociedade

The histone-like protein HupB influences biofilm formation and virulence in Xanthomonas citri ssp. citri through the regulation of flagellar biosynthesis

Citrus canker is an important disease of citrus, whose causal agent is the bacterium Xanthomonas citri ssp. citri (Xcc). In previous studies, we found a group of Xcc mutants, generated by the insertion of the Tn5 transposon, which showed impaired ability to attach to an abiotic substrate. One of these mutants carries the Tn5 insertion in hupB, a gene encoding a bacterial histone-like protein, homologue to the β-subunit of the Heat-Unstable (HU) nucleoid protein of Escherichia coli. These types of protein are necessary to maintain the bacterial nucleoid organization and the global regulation of gene expression. Here, we characterized the influence of the mutation in hupB regarding Xcc biofilm formation and virulence. The mutant strain hupB was incapable of swimming in soft agar, whereas its complemented strain partially recovered this phenotype. Electron microscope imaging revealed that impaired motility of hupB was a consequence of the absence of the flagellum. Comparison of the expression of flagellar genes between the wild-type strain and hupB showed that the mutant exhibited decreased expression of fliC (encoding flagellin). The hupB mutant also displayed reduced virulence compared with the wild-type strain when they were used to infect Citrus lemon plants using different infection methods. Our results therefore show that the histone-like protein HupB plays an essential role in the pathogenesis of Xcc through the regulation of biofilm formation and biosynthesis of the flagellum.Fil: Conforte, Valeria Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Malamud, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Yaryura, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; ArgentinaFil: Toum, Laila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Torres, Pablo Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: de Pino, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Chazarreta, Cristian Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Gudesblat, Gustavo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Castagnaro, Atilio Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Marano Roude, María de Los Milagros. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Vojnov, Adrián Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; Argentin

Criptosporidiose em pacientes acometidos pela síndrome de imunodeficiência adquirida (AIDS), no município de São Paulo, Brasil

Amostras de fezes de 157 pacientes acometidos pela síndrome de imunodeficiência adquirida, residentes no município de São Paulo, foram submetidas a diversas técnicas para pesquisa de Cryptosporidium sp.. Entre as diversas técnicas testadas para o preparo das lâminas (esfregaço direto, método de sedimentação espontânea e concentração pelo formol-éter) a concentração pelo formol-éter foi a que forneceu melhores resultados, superando nitidamente as demais. Nas 157 amostras preparadas por esta técnica, após coloração pelo método de Kinyoun ou pela fucsinacarbólica dimetilsulfóxido, encontraram-se 19 (12,1%) positivas para oocistos de Cryptosporidium sp..Stool samples of 157 patients with AIDS, living in the county of São Paulo, were submitted to several techniques in the search for Cryptosporidium sp.. Among the various techniques tested for slide preparation (direct smear, spontaneous sedimentation method, and formol-ether concentration), the latter, formol-ether concentration, offered the best results, clearly outdoing all the others. Nineteen samples out of 157 prepared by this technique, after dyeing by the Kinyoun method or by carbol fuchsin dimethyl sulfoxide, were found to be positive for Cryptosporidium sp.

Comparison of selection traits for effective popcorn (Zea mays L. var. Everta) breeding under water limiting conditions

Climate change is expected to intensify water restriction to crops, impacting on the yield potential of crops such as popcorn. This work aimed to evaluate the performance of 10 field cultivated popcorn inbred lines during two growing seasons, under well-watered (WW) and water stressed (WS) (ψsoil≥ -1.5 MPa) conditions. Water stress was applied by withholding irrigation in the phenological phase of male pre-anthesis. Additionally, two contrasting inbred lines, P7 (superior line) and L75 (low performer) were compared for grain yield (GY) and expanded popcorn volume (EPV), selected from previous studies, were tested under greenhouse conditions. In the field, no genotype x water condition x crop season (G×WC×CS) interaction was observed, whereas GY (-51%), EPV (-55%) and leaf greenness (SPAD index) measured 17 days after anthesis (DAA) (> -10%) were highly affected by water limitation. In general, root traits (angles, number, and density) presented G×WC×CS interaction, which did not support their use as selection parameters. In relation to leaf senescence, for both WS and WW conditions, the superior inbred lines maintained a stay-green condition (higher SPAD index) until physiological maturity, but maximum SPAD index values were observed later in WW (48.7 by 14 DAA) than in WS (43.9 by 7 DAA). Under both water conditions, negative associations were observed between SPAD index values 15 and 8 days before anthesis DBA), and GY and EPV (r ≥ -0.69), as well as between SPAD index 7, 17, and 22 DAA, and angles of brace root (AB), number of crown roots (NC) and crown root density (CD), in WS (r ≥ -0.69), and AB and CD, in WW (r ≥ -0.70). Lower NC and CD values may allow further root deepening in WS conditions. Under WS P7 maintained higher net photosynthesis values, stomatal conductance, and transpiration, than L75. Additionally, L75 exhibited a lower (i.e., more negative) carbon isotope composition value than P7 under WS, confirming a lower stomatal aperture in L75. In summary, besides leaf greenness, traits related to leaf photosynthetic status, and stomatal conductance were shown to be good indicators of the agronomic performance of popcorn under water constraint