769 research outputs found

    Capacity bounds for dense massive MIMO in a line-of-sight propagation environment

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    The use of large-scale antenna arrays grants considerable benefits in energy and spectral efficiency to wireless systems due to spatial resolution and array gain techniques. By assuming a dominant line-of-sight environment in a massive multiple-input multiple-output scenario, we derive analytical expressions for the sum-capacity. Then, we show that convenient simplifications on the sum-capacity expressions are possible when working at low and high signal-to-noise ratio regimes. Furthermore, in the case of low and high signal-to-noise ratio regimes, it is demonstrated that the Gamma probability density function can approximate the probability density function of the instantaneous channel sum-capacity as the number of served devices and base station antennas grows, respectively. A second important demonstration presented in this work is that a Gamma probability density function can also be used to approximate the probability density function of the summation of the channel's singular values as the number of devices increases. Finally, it is important to highlight that the presented framework is useful for a massive number of Internet of Things devices as we show that the transmit power of each device can be made inversely proportional to the number of base station antennas.20

    Understanding rostral-caudal auditory cortex contributions to auditory perception

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    There are functional and anatomical distinctions between the neural systems involved in the recognition of sounds in the environment and those involved in the sensorimotor guidance of sound production and the spatial processing of sound. Evidence for the separation of these processes has historically come from disparate literatures on the perception and production of speech, music and other sounds. More recent evidence indicates that there are computational distinctions between rostral and caudal primate auditory cortex that may underlie functional differences in auditory processing. These functional differences may originate from differences in the response times and temporal profiles of neurons in the rostral and caudal auditory cortex, suggesting that computational accounts of primate auditory pathways should focus on the implications of these temporal response differences

    Ictiofauna Da Bacia Do Rio Mundaú, Estado Do Ceará, Nordeste Do Brasil

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Mundaú river basin is located at Center-North Ceará State and occupies a total area of 2,227 km2, including Estuário do Rio Mundaú Environmental Protection Area. This study aimed to catalog the fishes of this basin. Collections were performed with active and passive gear in 35 sampling sites, between 2012 and 2014, in several habitats (main channels, streams, floodplains, permanent and temporary pools, ponds, and dams). A total of 2,545 specimens were collected, belonging to 55 species distributed in 10 orders, 31 families, and 50 genera; 30 of these are strictly freshwater species, and 25 estuarine-marine species. Three species (Hemigrammus guyanensis Gery, 1995, H. rodwayi Durbin, 1909 and Poecilia sarrafae Bragança & Costa, 2011) represent new records for the Mid-Northeastern Caatinga ecoregion. Besides, two cynolebiid species, Hypsolebias sp. and Anablepsoides cearensis (Costa & Vono, 2009), were found and the latter, currently classified as critically endangered, had its occurrence area widened. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17123038.005584/2012-20, CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorFUNCAP, Fundação Cearense de Apoio ao Desenvolvimento Científico e TecnológicoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    An Illustrative Case Of Léri-weill Dyschondrosteosis

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    We report on a girl presenting Léri-Weill dyschondrosteosis (LWD) due to deletion of the SHOX gene. Her family included individuals with short stature alone or with both short stature and mesomelia or Madelung's deformity. The deletion was demonstrated through detection of hemizygosity for microsatellite markdrs SHOX-CA repeat, DXYS10092, DXYS10093 and DXYS10091 localized around the SHOX gene, with retention of paternal alleles in the proband and three of her sisters who had short stature as the only clinical feature. Hemizygosity for these loci was also observed in their mother, who had short stature too. The deletion in the proband was however larger, including locus DXY 10083. The proband's only sister with normal height did not carry the deletion. Family history suggests transmission of the deletion from the proband's maternal great-grandfather to her grandfather via the Y chromosome, and from the grandfather to the proband's mother via the X chromosome after crossing-over in the pseudoautosomal region proximal to the SHOX gene. Copyright © 2008, Sociedade Brasileira de Genética.314839842Belin, V., Cusin, V., Viot, G., Girlich, D., Toutain, A., Moncla, A., Vekemans, M., Cormier-Daire, V., SHOX mutations in dyschondrosteosis (Léri-Weill syndrome) (1998) Nat Genet, 19, pp. 67-69Benito-Sanz, S., del Blanco, D.G., Aza-Carmona, M., Magano, L.F., Lapunzina, P., Argente, J., Campos-Barros, A., Heath, K.E., PAR1 deletions downstream of SHOX are the most frequent defect in a Spanish cohort of Léri-Weill dyschondrosteosis (LWD) probands (2006) Hum Mutat, 27, p. 1062Benito-Sanz, S., del Blanco, D.G., Huber, C., Thomas, N.S., Aza-Carmona, M., Bunyan, B., Maloney, V., Campos-Barros, A., Characterization of SHOX deletions in Léri-Weill dyschondrosteosis (LWD) reveals genetic heterogeneity and no recombination hotspots (2006) Am J Hum Genet, 79, pp. 409-412Benito-Sanz, S., Thomas, N.S., Huber, C., Gorbenko del Blanco, D., Aza-Carmona, M., Crolla, J.A., Maloney, V., Campos-Barros, A., A novel class of pseudoautosomal region 1 deletions downstream of SHOX Is associated with Léri-Weill dyschondrosteosis (2005) Am J Hum Genet, 77, pp. 533-544Clement-Jones, M., Schiller, S., Rao, E., Blaschke, R.J., Zuniga, A., Zeller, R., Robson, S.C., Strachan, T., The short stature homeobox gene SHOX is involved in skeletal abnormalities in Turner syndrome (2000) Hum Mol Genet, 9, pp. 695-702Ellison, J.W., Wardak, Z., Young, M.F., Gehron Robey, P., Laig-Webster, M., Chiong, W., PHOG, a candidate gene for involvement in the short stature of Turner syndrome (1997) Hum Mol Genet, 6, pp. 1341-1347Filatov, D.A., Gerrard, D.T., High mutation rates in human and ape pseudoautosomal genes (2003) Gene, 317, pp. 67-77Fukami, M., Kato, F., Tajima, T., Yokoya, S., Ogata, T., Transactivation function of an approximately 800-bp evolutionarily conserved sequence at the SHOX 3′ region: Implication for the downstream enhancer (2006) Am J Hum Genet, 78, pp. 167-170Henry, A., Thorburn, M.J., Madelung's deformity. A clinical and cytogenetic study (1967) J Bone Joint Surg, 49 B, pp. 66-73Jorge, A.A., Souza, S.C., Nishi, M.Y., Billerbeck, A.E., Liborio, D.C., Kim, C.A., Arnhold, I.J., Mendonca, B.B., SHOX mutations in idiopathic short stature and Leri-Weill dyschondrosteosis: Frequency and phenotypic variability (2007) Clin Endocrinol, 66, pp. 130-135Lien, S., Szyda, J., Schechinger, B., Rappold, G., Arnheim, N., Evidence for heterogeneity in recombination in the human pseudoautosomal region: High resolution analysis by sperm typing and radiation-hybrid mapping (2000) Am J Hum Genet, 66, pp. 557-566Rao, E., Weiss, B., Fukami, M., Rump, A., Niesler, B., Mertz, A., Muroya, K., Winkelmann, M., Pseudoautosomal deletions encompassing a novel homeobox gene cause growth failure in idiopathic short stature and Turner syndrome (1997) Nat Genet, 16, pp. 54-63Rappold, G., Blum, W.F., Shavrikova, E.P., Crowe, B.J., Roeth, R., Quigley, C.A., Ross, J.L., Niesler, B., Genotypes and phenotypes in children with short stature: Clinical indicators of SHOX haploinsufficiency (2007) J Med Genet, 44, pp. 306-313Rappold, G.A., Fukami, M., Niesler, B., Schiller, S., Zumkeller, W., Bettendorf, M., Heinrich, U., Onigata, K., Deletions of the homeobox gene SHOX(short stature homeobox) are an important cause of growth failure in children with short stature (2002) J Clin Endocrinol Metab, 87, pp. 1402-1406Schneider, K.U., Sabherwal, N., Jantz, K., Röth, R., Muncke, N., Blum, W.F., Cutler Jr, G.B., Rappold, G., Identification of major raombinant hotspot in patients with short stature and SHOX deficiency (2005) Am J Hum Genet, 77, pp. 89-96Shears, D.J., Vassal, H.J., Goodman, F.R., Palmer, R.W., Reardon, W., Superti-Furga, A., Scambler, P.J., Winter, R.M., Mutation and deletion of the pseudoautosomal gene SHOX cause Léri-Weill dyschondrosteosis (1998) Nat Genet, 19, pp. 70-72Zebala, L.P., Manske, P.R., Goldfarb, C.A., (200't) Madelung's deformity: A spectrum of presentation.. The J Hand Surg, 32 A, pp. 1393-1401Zinn, A.R., Ramos, P., Ross, J., (1006) A second recombination hotspot associated with SHOX deletions Am J Hum Genet, 78, pp. 523-52

    Fragmentation Experiment and Model for Falling Mercury Drops

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    The experiment consists of counting and measuring the size of the many fragments observed after the fall of a mercury drop on the floor. The size distribution follows a power-law for large enough fragments. We address the question of a possible crossover to a second, different power-law for small enough fragments. Two series of experiments were performed. The first uses a traditional film photographic camera, and the picture is later treated on a computer in order to count the fragments and classify them according to their sizes. The second uses a modern digital camera. The first approach has the advantage of a better resolution for small fragment sizes. The second, although with a poorer size resolution, is more reliable concerning the counting of all fragments up to its resolution limit. Both together clearly indicate the real existence of the quoted crossover. The model treats the system microscopically during the tiny time interval when the initial drop collides with the floor. The drop is modelled by a connected cluster of Ising spins pointing up (mercury) surrounded by Ising spins pointing down (air). The Ising coupling which tends to keep the spins segregated represents the surface tension. Initially the cluster carries an extra energy equally shared among all its spins, corresponding to the coherent kinetic energy due to the fall. Each spin which touches the floor loses its extra energy transformed into a thermal, incoherent energy represented by a temperature used then to follow the dynamics through Monte Carlo simulations. Whenever a small piece becomes disconnected from the big cluster, it is considered a fragment, and counted. The results also indicate the existence of the quoted crossover in the fragment-size distribution.Comment: 6 pages, 3 figure

    Ametryn leaching on Red-Yellow Latosol and Red-Yellow Ultisol with different pH values

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    Objetivou-se com este trabalho avaliar o potencial de lixiviação do ametryn num Argissolo Vermelho-Amarelo e num Latossolo Vermelho-Amarelo utilizados com pastagens no Brasil, com diferentes valores de pH. Para isso, foram avaliados 120 tratamentos (quatro solos associados a três intensidades de chuva e 10 profundidades), em parcela subdividida no delineamento inteiramente casualizado, com três repetições. Colunas de PVC de 50 cm de comprimento por 10 cm de diâmetro foram preenchidas com os solos e umedecidas; em seguida, aplicou-se o herbicida e simularam-se chuvas no topo delas, nas intensidades especificadas de acordo com o tratamento. Após 72 horas, todas as colunas foram dispostas na posição horizontal e abertas longitudinalmente, coletando-se amostras dos solos a cada intervalo de 5 cm de profundidade, para posterior extração e quantificação do herbicida e análise por cromatografia líquida de alta eficiência - CLAE. Posteriormente, no restante das amostras de solo, semeou-se ao longo de cada coluna a espécie indicadora Cucumis sativus. Concluiu-se que solos com baixo teor de matéria orgânica e/ou pH mais elevado apresentaram maiores índices de lixiviação do ametryn. Além disso, o método do bioensaio foi mais eficiente na confirmação da lixiviação do ametryn em comparação à CLAE.The objective of this work was to evaluate ametryn leaching potential in soil used for pasture in Brazil (Red-Yellow Latosol (LVA) and Red-Yellow Ultisol (PVA)) with different pH values. Thus, 120 treatments were evaluated (four soils related to three rainfall intensities and 10 soil column depths). The experiments were arranged in a completely randomized design in split-plots and three replications. PVC columns of 10 cm diameter by 50 cm length were filled with the soil samples, moistened and placed upright for 48 hours to drain the excess water. The herbicide was applied and rainfall was simulated on top of the columns at intensities specified according to the treatment. After 72 hours, the columns were opened longitudinally, placed in a horizontal position and soil samples were collected at each 5 cm interval depth for posterior herbicide extraction and quantification by liquid chromatography (HPLC). The remaining soil columns were sown with the indicator species (Cucumis sativus) in the substrate along the opening to evaluate ametryn leaching. After 21days of emergence, evaluations were conducted to verify the intoxication symptoms caused by ametryn in the plants. It was concluded that soils with low organic matter content and/or higher pH showed higher ametryn leaching rates, and that the bioassay method was more efficient in confirming ametryn leaching than liquid chromatography

    A Biased Review of Sociophysics

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    Various aspects of recent sociophysics research are shortly reviewed: Schelling model as an example for lack of interdisciplinary cooperation, opinion dynamics, combat, and citation statistics as an example for strong interdisciplinarity.Comment: 16 pages for J. Stat. Phys. including 2 figures and numerous reference

    Dopamine D1 receptor stimulation modulates the formation and retrieval of novel object recognition memory: role of the prelimbic cortex

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    Previous studies have shown that dopamine D1 receptor antagonists impair novel object recognition memory but the effects of dopamine D1 receptor stimulation remain to be determined. This study investigated the effects of the selective dopamine D1 receptor agonist SKF81297 on acquisition and retrieval in the novel object recognition task in male Wistar rats. SKF81297 (0.4 and 0.8mg/kg s.c.) given 15 min before the sampling phase impaired novel object recognition evaluated 10 min or 24h later. The same treatments also reduced novel object recognition memory tested 24h after the sampling phase and when given 15min before the choice session. These data indicate that D1 receptor stimulation modulates both the encoding and retrieval of object recognition memory. Microinfusion of SKF81297 (0.025 or 0.05 μg/side) into the prelimbic sub-region of the medial prefrontal cortex (mPFC) in this case 10 min before the sampling phase also impaired novel object recognition memory, suggesting that the mPFC is one important site mediating the effects of D1 receptor stimulation on visual recognition memory
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