The critical role of children and schools in internet adoption

Children are fast learners, and the speed at which they learn can have an impact on the broader adoption of new technology. In particular, the provision of broadband in schools can be an effective way to encourage household internet uptake in neighbouring areas

BROADBAND IN SCHOOLS: DOES IT HELP OR HURT STUDENT PERFORMANCE?

This paper provides empirical evidence on the effects of broadband Internet usage in schools on student performance in terms of national exams scores. We use a rich panel of data that has information on test scores, as well as broadband usage for all schools in Portugal, allowing us to control for school-specific effects. Additionally we use an instrument to account for possible unobserved time-varying effects. For 9th grade students, our estimates indicate that a higher use of broadband Internet is detrimental for students\u27 test scores, despite this effect seeming to be wearing off with time. We find that the adverse effect tends to be reinforced for boys and weakened for girls, compared to the pooled estimates. We also find that schools with worse performance right before the introduction of broadband Internet in schools suffered the most. Our results suggest that introduction of broadband Internet in schools is not enough to improve students\u27 performance. Broadband deployment in schools needs to be accompanied by complementary measures that support the use of the technology in productive ways

Target the ego or target the group: evidence from a randomized experiment in proactive churn management

We propose a new strategy for proactive churn management that actively uses social network information to help retain consumers. We collaborate with a major telecommunications provider to design, deploy, and analyze the outcomes of a randomized control trial at the household level to evaluate the effectiveness of this strategy. A random subset of likely churners were selected to be called by the firm. We also randomly selected whether their friends would be called. We find that listing likely churners to be called reduced their propensity to churn by 1.9 percentage points from a baseline of 17.2%. When their friends were also listed to be called, their likelihood of churn reduced an additional 1.3 percentage points. The client lifetime value of likely churners increased 2.1% with traditional proactive churn management, and this statistic becomes 6.4% when their friends were also listed to be called by the firm. We show that, in our setting, likely churners receive a signal from their friends that reduces churn among the former. We also discuss how this signal may trigger mechanisms akin to both financial comparisons and conformity that may explain our findings.info:eu-repo/semantics/acceptedVersio

Aplicação de zeólitos hierárquicos a reacções de acilação de Friedel-Crafts

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia QuímicaEste trabalho teve por objectivo estudar o comportamento catalítico de zeólitos comerciais e hierárquicos como catalisadores alternativos na reacção de acilação de Friedel-Crafts de heteroaromáticos, na perspectiva de contribuição para uma química reaccional mais ecológica. Numa primeira fase do trabalho foram testados várias estruturas zeolíticas microporosas e hierárquicas – MOR, MFI e BEA, bem como o zeólito MCM-22, previamente sintetizado. Após uma primeira série de resultados foram seleccionadas as estruturas BEA e MCM-22 para continuar o trabalho. No caso do zeólito BEA foi realizado um estudo mais abrangente, usando várias razões Si/Al, onde os materiais foram sujeitos a tratamentos de dessilicação e dessilicação seguido de tratamento ácido de modo a obter zeólitos hierárquicos. Os tratamentos de dessilicação deram origem a um aumento da mesoporosidade e redução de microporosidade, devido à transformação dos microporos em mesoporos. No entanto este tratamento teve como consequência alguma obstrução dos microporos com espécies extra-rede provenientes do tratamento alcalino. O tratamento ácido posterior revelou-se bastante eficaz na remoção de espécies extra-rede provenientes da dessilicação, contribuindo a nível geral para o aumento da porosidade das amostras e acessibilidade aos centros activos dos catalisadores. Os materiais de partida, juntamente com as amostras modificadas, foram caracterizadas por difracção de raios-X, ressonância magnética nuclear de 29Si e 27Al, análise elementar por absorção atómica e adsorção de azoto a -196ºC. Na reacção de acilação de Friedel-Crafts de heteroaromáticos verificou-se que as amostras do tipo BEA foram as que proporcionaram um rendimento superior, independentemente do substrato da reacção em estudo. Para o furano, que foi o heteroaromático mais estudado, verificaram-se os melhores rendimentos. Para o pirrole, heteroaromático cuja polaridade superior contribui para o menor número de interacções zeólito-substrato, observaram-se menores rendimentos do que o furano e ainda a formação de dois isómeros monoacilados. Para o anisol, verificou-se rendimentos ainda inferiores ao obtido para as duas moléculas anteriores, o que se deve à elevada desactivação causada pelo produto acilado do anisol, que é fortemente adsorvido pelos catalisadores. Este fenómeno é particularmente visível nas amostras dessilicadas, principalmente as que são provenientes do zeólito MCM-22, cujo entupimento das entradas das supercavidades reduzem em muito o acesso aos centros ácidos e a desadsorção dos produtos reaccionais.Abstract: This work aimed to study the catalytic behaviour of commercial and hierarchical zeolites like alternative catalysts in reaction of Friedel-Crafts acylation of heteroaromatic, in perspective of contribution to a greener reaction chemistry. In a first phase of work were tested several microporous and hierarchical zeolites structures - MOR, MFI and BEA, as well as the MCM-22 zeolite, previously synthesized. After a first series of results were selected BEA and MCM-22 structures to continue the work. In the case of zeolite BEA was carried out a more comprehensive study, using severals Si/Al ratios, where the materials were subjected to treatments of desilication and desilication followed by acid treatment for hierarchical zeolites. Desilication treatments led to an increase in mesoporosity and reduction of microporosity, due to the transformation of micropores in mesoporous. However this treatment has resulted in some obstruction of micropores, caused by extra -framework species from the alkaline treatment. Acid treatment later proved to be quite effective in removing extra framework species generated from desilication treatment, contributingfor and increased porosity of samples and access to active centers of catalysts. The starting materials, along with the modified samples were characterized by X-ray diffraction, nuclear magnetic resonance of 27Al and 29Si, elemental analysis by atomic absorption and adsorption of nitrogen to -196°C. In reaction of Friedel-Crafts acylation of heteroaromatic was found that samples of type BEA provided the higher yields, regardless of the substrate of the reaction under investigation. For furan, which was the most studied heteroaromatic, the best yields was observed. For the pirrole, heteroaromatic whose higher polarity contributes to the smallest number of zeolite-substrate interactions, lower yield were observed than the furan and the formation of two monoacylated isomers. For anisole, the obtained yield there was still lower than the yields obtained for the two previous molecules, which is due to the high deactivation caused by acylated product of anisole,which is strongly adsorbed by catalysts. This phenomenon is particularly visible in the desilicated samples, mainly those from the zeolite MCM-22, whose entries blocking the supercages reducing the acidic centres access and desorption of products

The RBP's mission in the continuing medical education

Universidade de São Paulo Departamento de PsiquiatriaDuke University Departamento de Psicologia e NeurociênciaUniversidade Federal doRio de Janeiro Instituto dePsiquiatria Departamento de Psiquiatria e Medicina LegalUniversidade de São Paulo Faculdade de Medicina Instituto de PsiquiatriaUniversidade Federal do Rio Grande do Sul Departamento de PsiquiatriaUniversidade Federal de São Paulo (UNIFESP) Departamento de PsiquiatriaUNIFESP, Depto. de PsiquiatriaSciEL

Solid-state fermentation of plant feedstuff mixture affected the physiological responses of European seabass (Dicentrarchus labrax) reared at different temperatures and subjected to salinity oscillation

This study aimed to evaluate the effects of dietary inclusion of plant feedstuff mixture (PFM) pre-treated by solid-state fermentation (SSF) on the physiological responses of European seabass. For that purpose, two diets were formulated to contain: 20% inclusion level of non-fermented plant ingredients mixture (20Mix) and 20Mix fermented by A. niger in SSF conditions (20Mix-SSF). Seabass juveniles (initial body weight: 20.9 ± 3.3 g) were fed the experimental diets, reared at two different temperatures (21 and 26 °C) and subjected to weekly salinity oscillations for six weeks. Growth performance, digestive enzyme activities, humoral immune parameters, and oxidative stress indicators were evaluated. A reduction in weight gain, feed intake, and thermal growth coefficient was observed in fish fed the fermented diet (20Mix-SSF). Salinity oscillation led to an increase in weight gain, feed efficiency, daily growth index, and thermal growth coefficient, regardless of dietary treatment. Higher rearing temperatures also increased daily growth index. No dietary effect was observed on digestive enzymes activities, whereas rearing temperature and salinity oscillation modulated digestive enzyme activities. Oxidative stress responses were significantly affected by experimental diets, temperature, and salinity conditions. Catalase and glutathione peroxidase activities showed an interactive effect. Fish reared at 21 °C showed higher enzymatic activity when fed the 20Mix-SSF. Conversely, fish reared at 26 °C showed higher GPx activity when fed the 20Mix diet. Fish reared at 26 °C showed reduced peroxidase and lysozyme activities, while salinity fluctuation led to increased lysozyme activity and decreased ACH50 activity. ACH50 activity increased in fish fed the 20Mix-SSF. Overall, the dietary inclusion of PFM fermented by A. niger was unable to mitigate the impact of environmental stress on physiological performance in European seabass. In fact, fermented feed caused an inhibition of growth performances and an alteration of some physiological stress indicators.This work was funded by the Ocean3R project (NORT-01-0145-FEDER-000064), supported by the North Portugal Regional Operational Program (NORT2020), under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF). This research was partially supported by national funds through FCT—Foundation for Science and Technology within the scope of UIDB/04423/2020 and UIDP/04423/2020.info:eu-repo/semantics/publishedVersio

Solid-state fermentation as green technology to improve the use of plant feedstuffs as ingredients in diets for european sea bass (Dicentrarchus labrax) juveniles

This study aimed to evaluate the utilization by juvenile European sea bass of a SSFed PF mixture with Aspergillus niger CECT 2088. A 22-day digestibility and a 50-day growth trial were performed testing four diets, including 20 or 40% of an unfermented or SSFed PF mixture (rapeseed, soybean, rice bran, and sunflower seed meals, 25% each). SSF of the PF added cellulase and β-glucosidase activity to the diets. Mycotoxin contamination was not detected in any of the experimental diets except for residual levels of zearalenone and deoxynivalenol (100 and 600 times lower than that established by the European Commission Recommendation-2006/576/EC). In diets including 20% PF, SSF did not affect growth but increased apparent digestibility coefficients of protein and energy, feed efficiency, and protein efficiency ratio. On the contrary, in diets including 40% PF, SSF decreased growth performance, feed intake, feed and protein efficiency, and diet digestibility. SSF decreased the intestinal amylase activity in the 40% SSFed diet, while total alkaline proteases decreased in the 20% and 40% SSFed diets. Hepatic amino acid catabolic enzyme activity was not modulated by SSF, and plasma total protein, cholesterol, and triglyceride levels were similar among dietary treatments. In conclusion, dietary inclusion of moderate levels of the SSFed PF, up to 20%, improves the overall feed utilization efficiency without negatively impacting European sea bass growth performance. The replacement of PF with the SSFed PF mixture may contribute to reducing the environmental footprint of aquaculture production.Simple Summary: The rapid growth of the world’s population has increased the demand for seafood, leading to the expansion of aquaculture to fulfill these needs and reduce the pressure on wild fish stocks. Plant feedstuffs (PFs) are often used as the main protein source in aquafeeds due to their wide availability and low cost. However, PFs usually contain high levels of non-starch polysaccharides that limit their utilization in aquafeeds, mainly for carnivorous fish. Solid-state fermentation (SSF) is a cost-effective technological process that may reduce anti-nutritional factor levels while improving nutrient digestibility and the production of several bioactive compounds, enhancing feedstuffs’ nutritional value in aquafeeds. Hence, this study evaluated the effects of using a PF mixture (rapeseed, soybean, rice bran, and sunflower seed meals, 25% each) solid-state fermented (SSFed) with Aspergillus niger CECT 2088 at two inclusion levels (20% and 40%) on European sea bass juveniles’ growth performance, feed digestibility, digestive and catabolic enzyme activity, and plasma metabolites. Overall, the SSFed PF mixture improved the overall feed digestibility, and utilization efficiency, when included at balanced level (20%) without negatively impacting fish growth performance, but not at the higher level (40%).Fundação para a Ciência e a Tecnologia | Ref. UIDB/04423/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/04423/2020Fundação para a Ciência e a Tecnologia | Ref. 2020.05525.BDFundação para a Ciência e a Tecnologia | Ref. SFRH/BD/115870/2016Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/137919/2018Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/143614/201

The impact of time shifting on TV consumption and ad viewership

In this paper we study the impact of time shifting on TV consumption and ad viewership. We analyze the results of a field experiment in which a random sample of “triple-play” households were given a set of premium TV channels broadcasting popular movies and TV shows without commercial breaks. A random subset of these households were given access to these channels with time shifting (automated cloud recording for later viewing or rewinding of broadcasted programs), while the remainder were not. This design allowed us to identify the effects of time shifting on TV consumption. On average, we found that receiving access to the channels with time shifting increased total TV consumption because it increased time-shifted viewership while leaving live viewership unchanged. The increase in the live viewership of these channels was similar to the reduction in the live viewership of the originally available channels, resulting in a net zero effect on live viewership. It appears that time shifting does not change the concentration of live viewership, but it does increase the concentration of total TV viewership, because it is used disproportionately to watch the most popular programs. Finally, we found that time shifting does not change the likelihood of skipping ads during live viewership, suggesting that households

Radioterapia em paciente com neoplasia pulmonar e marcapasso ipsilateral

Durante anos, o tratamento com radioterapia de portadores de dispositivos eletrônicos implantáveis foi considerado perigoso. Se a zona a ser irradiada envolvesse o lado em que o dispositivo estivesse localizado, a estratégia envolvia inclusive mudanças no local do implante. Passaram-se os anos e tanto os dispositivos como a radioterapia evoluíram, e o que antes era regra para a segurança do binômio marcapasso-radioterapia hoje pode ser exceçao. Relatamos o caso de um paciente portador de neoplasia maligna de lobo superior de pulmao direito, em posiçao ipsilateral ao marcapasso implantado previamente