Field-emission Properties Of Sulphur Doped Nanocrystalline Diamonds

Nanostructured diamond doped with sulphur has been prepared using a hot-filament assisted chemical vapour deposition system fed with an ethyl alcohol, carbon disulfide, hydrogen, and argon mixture. The reduction of diamond grains to the nanoscale is relevant to create a network of defective grain boundaries which may be n-type doped to facilitate the transport and injection of electrons to the diamond grains located at the vacuum interface, enhancing the electron field-emission properties of the samples. The downsizing was produced by secondary nucleation and defects induced by sulphur and argon atoms in the chemical vapour deposition surface reactions. Sulphur also acts as an n-type dopant of diamond. Raman measurements show that the samples are nanodiamonds embedded in a matrix of graphite and disordered carbon grains and the morphology, revealed by field electron scanning microscopy, shows that the grains are in the range of 10 to 30 nm. The lowest threshold achieved for field emission was 13.20 V/μm. © 2007 IOP Publishing Ltd.6116670Yang, A.T.S., Lay, J.Y., Wong, M.S., Cheng, C.L., (2002) J. Appl. Phys., 92 (4), p. 2133Mammana, V.P., Tea, S., Mammana, A., Baranauskas, V., Ceragioli, H.J., Peterlevitz, A.C., (2002) Appl. Phys. Lett., 81 (18), p. 3470Baranauskas, V., Fontana, M., Ceragioli, H.J., Peterlevitz, A.C., (2004) Nanotech., 15 (10), p. 678Gruen, D.M., (1998) MRS Bull., 9, p. 32Jin, B.M., Kim, C.C., (1997) Appl. Phys. A: Solid Surf., 65 (1), p. 53Himpsel, F.J., Knapp, J.A., Vanvechten, J.A., Eastman, P.E., (1979) Phys. Rev., 20 (2), p. 624Bandis, B., Pate, B.B., (1996) Appl. Phys Lett., 69 (3), p. 366Okano, K., Yamada, T., Suave, A., Koizumi, S., Pate, B.B., (1999) Appl. Surf. Sci., 146 (1-4), p. 274Kurt Bonard, R.J.M., Karimi, A., (2001) Diam. Rel. Mater., 10 (11), p. 1962Bonnot, A.M., Deldem, M., Beaugnon, M., Fournier T.schouler, M.C., Mermoux, M., (1999) Diam. Rel. Mater., 8 (2-5), p. 631Gruen, D.M., Liu, S., Krauss, A.R., Liuy, A., Luo, J., Foster, C.M., (1994) J. Vac. Sci. Technol., 12 (4), p. 1491Gupta Weiner, S.B.R., Morell, G., (2002) Diam. Rel. Mater., 11 (3-6), p. 799Gupta Weiner, S.B.R., Morell, G., (2005) J. Appl. Phys., 97, p. 094307Morell, G., Gonzlez-Berríos, A., Weiner, B.R., Gupta, S., (2006) J. Mater. Sci: Mater. Electron, 17 (6), p. 443Koeck, F.A.M., Zumer, M., Nemanic, V., Nemanich, R.J., (2006) Diam. Rel. Mater., 15 (4-8), p. 880Shroder Nemanich, R.E.R.J., Glass, J.T., (1990) Phys. Rev., 41 (6), p. 3738Birrell, J., Gerbi, J.E., Auciello, O., Gibson, J.M., Johnson, J., Carlisle, J.A., (2005) Diam. Rel. Mater., 14 (1), p. 86Ferrari, A.C., Robertson, J., (2001) Phys. Rev., 63, pp. 121405RWu, K., Wang, E.G., Cao, Z.X., Wang, Z.L., Jiang, X., (2000) J. Appl. Phys., 88 (5), p. 2967Proffitt, S.S., Probert, S.J., Whitfield, M.D., Foord, J.S., Jackman, R.B., (1999) Diam. Rel. Mater., 8 (2-5), p. 76

Revisión bibliométrica de la producción científica en balonmano

El propósito de este estudio fue realizar una revisión bibliométrica de la producción científica en balonmano. Las publicaciones se recopilaron de las bases de datos Web of Science y MEDLINE en el periodo 1900-2012 y 1950-2012 respectivamente. El análisis evaluó el tipo de documento, idioma, tendencia anual de publicación, número medio de autores por artículo, disciplinas y temas de investigación, tendencias de publicación en las disciplinas de investigación, principales revistas, productividad de autores y distribución por países. Solo los artículos centrados principalmente en balonmano fueron considerados, para un total de 373 artículos. En los últimos años se observó un incremento significativo en el número de artículos publicados y en el número medio de autores por artículo, lo que permite considerar al balonmano como un área de investigación en expansión, tanto en términos de producción científica como en colaboración entre investigadores. La medicina deportiva fue la disciplina con más publicaciones, siendo los estudios de lesiones el tema principal. En las últimas dos décadas se observó un destacable crecimiento anual en las disciplinas de teoría del entrenamiento deportivo, antropometría y biomecánica. En el 87,94% de los artículos participaron autores europeos, siendo los noruegos los más prolíficos, lo que revela el dominio de Europa en la investigación en balonmano. Este estudio aporta información sobre potenciales líneas de investigación para el futuro, tanto para investigadores como para instituciones académicas interesadas en el balonmano

A importância da alimentação em paralisia cerebral

Uma das definições mais recentes da paralisia cerebral descreve-a como um grupo de alterações permanentes, mas não inalteráveis,do movimento e da postura, que causa limitações na atividade, as quais são atribuídas a lesões não progressivas queocorrem no cérebro imaturo e em desenvolvimento.Nesta população são comuns as dificuldades alimentares. Estas podem resultar de uma deficiência oro-motora (dificuldadesde mastigação e/ou deglutição), disfagia e deficiência sensorial, com ou sem distúrbios comportamentais. A estas dificuldadesalimentares podem, ainda, estar associados problemas de saúde como aspiração de alimentos e infeções pulmonares, refluxogastroesofágico e obstipação. A baixa ingestão hídrica, ou até mesmo desidratação, o aumento do tempo despendido paraefetuar uma refeição e a ingestão insuficiente (que pode levar a baixo peso) são outras das consequências destes problemasna alimentação. Por outro lado, existem situações em que é comum observar-se excesso ponderal por diversas razões (porexemplo, sedentarismo).A intervenção a nível alimentar/nutricional é, por isso, fundamental para a melhoria da qualidade de vida do indivíduo. É, ainda,imprescindível que os cuidadores disponham de toda a informação e motivação para lidar com as suas especificidades, de formaa que as refeições sejam o mais agradáveis e seguras possível. Nesta população, a alimentação pode ser o nosso maior aliadoOne of the most recent definitions of cerebral palsy describes it as a group of permanent changes, but not unchangeable, of themovement and posture, causing limitations in activity, that are attributed to non-progressive damage occurring in the immaturebrain and under development.In this population feeding difficulties are common. These can result from oral-motor disability (chewing and/or swallowing difficulties),dysphagia and sensory impairment, with or without behavioral disorders. These feeding difficulties may also be associatedwith common health problems, such as aspiration and lung infections, gastroesophageal reflux and constipation. Low water intake,or even dehydration, the increase in the time to take a meal and insufficient intake (which can lead to low weight) are otherconsequences of feeding problems. On other hand, there are situations where it is common overweight for various reasons (forexample, sedentary lifestyle).Dietary/nutritional intervention is essential to improve the individuals quality of life. It is also primordial that caregivers are providedwith all the information and motivation to address their specificities, so that the meals are as pleasant and safe as possible. In thispopulation, food can be our greatest ally

Characterization Of Boron Doped Nanocrystalline Diamonds

Nanostructured diamond doped with boron was prepared using a hot-filament assisted chemical vapour deposition system fed with an ethyl alcohol, hydrogen and argon mixture. The reduction of the diamond grains to the nanoscale was produced by secondary nucleation and defects induced by argon and boron atoms via surface reactions during chemical vapour deposition. Raman measurements show that the samples are nanodiamonds embedded in a matrix of graphite and disordered carbon grains, while morphological investigations using field electron scanning microscopy show that the size of the grains ranges from 20 to 100 nm. The lowest threshold fields achieved were in the 1.6 to 2.4 V/μm range. © 2008 IOP Publishing Ltd.100PART 5Himpsel, F.J., Knapp, J.A., VanVechten, J.A., Eastman, P.E., (1979) Phys. Rev., 20 B, p. 624Bandis, B., Pate, B.B., (1996) Appl. Phys Lett., 69, p. 366Mammana, V.P., Santos, T.E.A., Mammana, A., Baranauskas, V., Ceragioli, H.J., Peterlevitz, A.C., (2002) Appl. Phys. Lett., 81, p. 3470Baranauskas, V., Fontana, M., Ceragioli, H.J., Peterlevitz, A.C., (2004) Nanotech., 15 (10), pp. S678Shroder, R.E., Nemanich, R.J., Glass, J.T., (1990) Phys. Rev., 41 B, p. 3738Ferrari, A.C., Robertson, J., (2001) Phys. Rev., 63 B. , 121405(R)Jiang, X., Frederick, C.K.Au., Lee, S.T., (2002) J. Appl. Phys., 92 (5), p. 2880Lee, Y.C., Lin, S.J., Lin, I.N., Cheng, H.F., (2005) J. Appl. Phys., 97, p. 05431

METODOLOGIA DE ENSINO DE GEOMORFOLOGIA NA REGIÃO DO NORDESTE DE MINAS GERAIS E EXTREMO SUL DA BAHIA

Metodologias eficazes na compreensão da geomorfologia podem se tratar de técnicas inovadoras ou variações eficientes das tradicionais. Este artigo aborda a construção do conhecimento por aulas teóricas, elaboração pré-relatório para trabalho de campo baseado em aulas teóricas e pesquisas em artigos, livros e periódicos, em seguida, execução deste e a finalização do relatório apresentando os resultados e discussões das análises executadas no decorrer do percurso Teófilo Otoni/MG a Prado/BA

Leguminous cover crops improve the profitability and the sustainability of rainfed olive (Olea europaea L.) orchards: from soil biology to physiology of yield determination

The olive sector has a crucial economic, social, cultural and ecological relevance in the Mediterranean region, where tillage and herbicides application still are generalized practices. However, these techniques oppose to the recommendations of UE policy. Thus, other methods are needed to reduce adverse environmental impacts and to improve biodiversity, soil carbon sink and fertility, to save fossil fuels and to increase yield and the safety and nutritional value of food products. Meanwhile, since Mediterranean basin is particularly vulnerable to climate change, including lower precipitation in summer, olive tree will experiment some hard changes, mainly under rainfed conditions. Therefore, we propose an adequate management of cover crops to shift tillage and herbicides, in order to minimize runoff and evaporation water losses, conserve soil moisture storage and promote the infiltration of water in soil. The experiment was carried out during 4 years on a commercial orchard (cv. Cobrançosa) in Northeast Portugal. The treatments laid out were: (1) ordinary tillage techniques (OT) used by local growers (two tillage trips per year); (2) cover crop with self-reseeding annual legume species (AL); (3) natural vegetation fertilized (NVF) with 60 kg N hm2 (as in OT); (4) natural vegetation (NV) left unfertilized. The results revealed that AL treatment is the best option, reaching 37, 53 and 95% higher cumulative yield than NVF, OT and NV, respectively, in a closely association with greater physiological performance during the summer, mainly evidenced by lower oxidative damage and by favourable changes in water status and net photosynthetic rate, due to lower stomatal and mesophyll limitations. Moreover, the AL covered soil presented considerable microbial diversity and enzymatic activities, which may contribute to promote and conserve soil quality and health, as well the stability of ecosystems. Thus, leguminous cover crops improve the profitability and the sustainability of rainfed olive orchards.info:eu-repo/semantics/publishedVersio

Naturalness and theoretical constraints on the Higgs boson mass

Arbitrary regularization dependent parameters in Quantum Field Theory are usually fixed on symmetry or phenomenology grounds. We verify that the quadratically divergent behavior responsible for the lack of naturalness in the Standard Model (SM) is intrinsically arbitrary and regularization dependent. While quadratic divergences are welcome for instance in effective models of low energy QCD, they pose a problem in the SM treated as an effective theory in the Higgs sector. Being the very existence of quadratic divergences a matter of debate, a plausible scenario is to search for a symmetry requirement that could fix the arbitrary coefficient of the leading quadratic behavior to the Higgs boson mass to zero. We show that this is possible employing consistency of scale symmetry breaking by quantum corrections. Besides eliminating a fine-tuning problem and restoring validity of perturbation theory, this requirement allows to construct bounds for the Higgs boson mass in terms of $\delta m^2/m^2_H$ (where $m_H$ is the renormalized Higgs mass and $\delta m^2$ is the 1-loop Higgs mass correction). Whereas $\delta m^2/m^2_H<1$ (perturbative regime) in this scenario allows the Higgs boson mass around the current accepted value, the inclusion of the quadratic divergence demands $\delta m^2/m^2_H$ arbitrarily large to reach that experimental value.Comment: 6 pages, 4 figure

Key Game Indicators in NBA Players’ Performance Profiles

The aim of the present study was to identify and describe players’ performances in NBA games using individual and team-based game variables. The sample was composed by 535 balanced games (score differences below or equal to eight points) from the regular season (n=502) and the playoffs (n=33). A total of 472 players were analysed. The individual-based variables were: minutes on court, effective field-goal percentage, free-throws/field-goals ratio, offensive rebound percentage, turnover percentage and playing position. The team-based variables were: team points minus opponent’s points (on and off court), NET score (player’s on values minus his/her off values), maximum negative and positive point difference, team’s winning percentage, game pace, defensive and offensive ratings. A two-step cluster analysis was performed to identify the player’s profiles during regular season and playoff games. The results identified five performance profiles during regular season games and four performance profiles during playoff games. The profiles identified were mainly characterized by the game quarter and the negative NET indicator (players’ performance on court minus their performance off court) in regular season games and the positive NET indicator during playoff games and second and third game-quarters. Coaching staffs can fine-tune these profiles to develop more team-specific models and, conversely, use the results to monitor and rebuild team formation under the constrained dynamics of the game and competition stages

Synthesis And Characterization Of Boron-doped Carbon Nanotubes

Boron-doped carbon nanotubes have been prepared by chemical vapour deposition of ethyl alcohol doped with B2O3 using a hot-filament system. Multi-wall carbon nanotubes of diameters in the range of 30 - 100 nm have been observed by field emission scanning electron microscopy (FESEM). Raman measurements indicated that the degree of C-C sp2 order decreased with boron doping. Lowest threshold fields achieved were 1.0 V/μm and 2.1 V/μm for undoped and boron-doped samples, respectively. © 2008 IOP Publishing Ltd.100PART 5Bonard, J.M., Kind, H., Stöckli, T., Nilsson, L.O., (2001) Sol. State Electron., 45, p. 893Maultzsch, J., Reich, S., Thomsen, C., Webster, S., Czerw, R., Carroll, D.L., Vieira, S.M.C., Rego, C.A., (2002) Appl.Phys.Lett., 81, p. 2647Mondal, K.C., Coville, N.J., Witcomb, M.J., Tejral, G., Havel, J., (2007) Chem. Phys. Lett., , in pressChen, C.F.C., Tsai, C.L., Lin, C.L., (2003) Diam. Rel. Mater., 12, p. 1500Sharma, R.B., Late Joag, D.S., Govindaraj Rao, C.N.R., (2006) Chem.Phys.Lett, 428, p. 102Mennella, V., Monaco, G., Colanoeli, L., Bussoletti, E., (1995) Carbon, 33 (2), p. 11