1,678 research outputs found

    Generalized retarded integral inequalities

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    We prove some new retarded integral inequalities. The results generalize those in [J. Math. Anal. Appl. 301 (2005), no. 2, 265--275].Comment: Changes suggested by the referee don

    Phenotype and genotype correlation of the microconversion from the CYP21A1P to the CYP21A2 gene in congenital adrenal hyperplasia

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    Deficiency of 21-hydroxylase is the most common form of congenital adrenal hyperplasia (CAH-21OH). We determined by allele-specific PCR the frequency of microconversion in the CYP21A2 gene in 50 Brazilian patients with the classical (salt wasting: SW and simple virilizing: SV) forms and nonclassical (NC) form of CAH-21OH and correlated genotype with phenotype. Genotypes were classified into three mutation groups (A, B, and C) based on the amount of enzymatic activity in in vitro studies using adrenal cells. In 94 unrelated alleles, we diagnosed 76% of the affected alleles after screening for 7 microconversions. The most frequent point mutations observed in this series were I172N (19%), V281L (18%), and IVS2,A/C>G,-12 (15%). In the SW form, the most frequent mutation was IVS2,A/C>G,-12 (38%), in the SV form it was I172N (53%), and in the NC form it was V281L (57.7%). We observed a good correlation between genotype and phenotype. Discordance between genotype and phenotype was found in one SV patient with a mild mutation in one of the alleles (R356W/V281L). However, we cannot rule out the presence of an additional mutation in these alleles. We also observed a good correlation of genotype with 17alpha-hydroxyprogesterone, testosterone, and androstenedione levels. The severity of external genitalia virilization correlated with the severity of mutation. In conclusion, the frequencies described in the present study did not differ from worldwide studies, including the Brazilian population. The few differences observed may reflect individual sample variations. This new Brazilian cohort study suggests the presence of new mutations in Brazilian patients with different forms of CAH-21OH.1311131

    Optimality conditions for the calculus of variations with higher-order delta derivatives

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    We prove the Euler-Lagrange delta-differential equations for problems of the calculus of variations on arbitrary time scales with delta-integral functionals depending on higher-order delta derivatives.Comment: Submitted 26/Jul/2009; Revised 04/Aug/2010; Accepted 09/Aug/2010; for publication in "Applied Mathematics Letters

    Atomic X-ray Spectroscopy of Accreting Black Holes

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    Current astrophysical research suggests that the most persistently luminous objects in the Universe are powered by the flow of matter through accretion disks onto black holes. Accretion disk systems are observed to emit copious radiation across the electromagnetic spectrum, each energy band providing access to rather distinct regimes of physical conditions and geometric scale. X-ray emission probes the innermost regions of the accretion disk, where relativistic effects prevail. While this has been known for decades, it also has been acknowledged that inferring physical conditions in the relativistic regime from the behavior of the X-ray continuum is problematic and not satisfactorily constraining. With the discovery in the 1990s of iron X-ray lines bearing signatures of relativistic distortion came the hope that such emission would more firmly constrain models of disk accretion near black holes, as well as provide observational criteria by which to test general relativity in the strong field limit. Here we provide an introduction to this phenomenon. While the presentation is intended to be primarily tutorial in nature, we aim also to acquaint the reader with trends in current research. To achieve these ends, we present the basic applications of general relativity that pertain to X-ray spectroscopic observations of black hole accretion disk systems, focusing on the Schwarzschild and Kerr solutions to the Einstein field equations. To this we add treatments of the fundamental concepts associated with the theoretical and modeling aspects of accretion disks, as well as relevant topics from observational and theoretical X-ray spectroscopy.Comment: 63 pages, 21 figures, Einstein Centennial Review Article, Canadian Journal of Physics, in pres

    Modelação da actividade de voo da mosca-da-azeitona, Bactrocera oleae (Gmelin) para previsão do risco de prejuízos

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    A mosca da azeitona, Bactrocera (Gmelin), é o principal inimigo da oliveira a nível mundial, cujos prejuízos, em alguns anos, ultrapassam o valor da produção. Uma avaliação correcta do risco de prejuízos e essencial para a definição de estratégias racionais de protecção da cultura. Os modelos de simulação do desenvolvimento da cultura e das principais pragas a ela associadas podem ser utilizados na avaliação do risco de prejuízos, permitindo fundamentar adequadamente as tomadas de decisão fitossanitária, limitando as intervenções as situações em que para tal exista justificação de natureza económica

    Microwave irradiation synthesis to obtain La0.7-xPrxCa0.3MnO3 perovskites : electrical and electrochemical performance

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    Atzin Ferrel is grateful for her grants from CONACYT and SIP- IPN. The authors also appreciate the financial support provided by the Consejo Nacional de Ciencia y Tecnología (CONACYT), México, Comisión de Operación y Fomento de Actividades Académicas del IPN (COFAA), México and Secretaría de Investigación y Posgrado (SIP) of the Instituto Politécnico Nacional (IPN) México through the CB2015–252181, 20201278, 20201279, 20201280, 20202443 and 20200909 projects as well as the SNI-CONACyT.La0.7-xPrxCa0.3MnO3 (LPCM) perovskites previously synthesized by the microwave-assisted method at 4 min and with different stoichiometry (x = 0.35, 0.52 and 0.63) were evaluated through thermogravimetric analysis (TGA), electrical conductivity, thermal expansion coefficient (TEC), scanning electron microscopy (SEM), Brunauer- Emmet- Teller (BET) analysis and electrochemical impedance spectroscopy (EIS) using yttria stabilized zirconia (YSZ) as an electrolyte. The results are discussed in terms of the potential as cathode material to be applied in solid oxide fuel cells (SOFCs) applications at temperatures from 600 to 800 °C. Results derived from TGA showed that Pr promotes the uncoupling oxygen and oxygen vacancies favoring the fuel combusting. Also, TEC analysis revealed adequate stability between the YSZ electrolyte and the La0.7-xPrxCa0.3MnO3 to avoid cracking or failing, especially with high amount of Pr. The transition in morphology from irregular to regular shapes improves the BET and Barret- Joyner- Halenda (BJH) surfaces and promotes the triple phase boundary (TPB) connectivity. The electrical conductivity correlated to the availability in oxygen vacancies showed maximum conductivities in the order of 10−2 S cm−1. Activation energy (Ea) was found to be reduced with a minimum quantity of Pr (0.071 eV). EIS results indicate that the oxygen vacancies in the LPCM/YSZ system were better promoted with the highest amount of Pr = 0.63 (η = 0.9 V, 800 °C and 0.06 V of amplitude) in comparison with the minimum, Pr = 0.35 (η = 1.2 V, 800 °C and 0.06 V of amplitude).PostprintPeer reviewe

    Isoperimetric problems of the calculus of variations with fractional derivatives

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    In this paper we study isoperimetric problems of the calculus of variations with left and right Riemann-Liouville fractional derivatives. Both situations when the lower bound of the variational integrals coincide and do not coincide with the lower bound of the fractional derivatives are considered.Comment: Submitted 02-Oct-2009; revised 30-Jun-2010; accepted 10-May-2011; for publication in the journal Acta Mathematica Scienti

    Dental Caries And Treatment Needs In Adolescents From The State Of Sao Paulo, Brazil

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    Objective: To estimate the prevalence of dental caries and treatment needs in 12-year-olds and adolescents. Methods: Cross-sectional study based on results from the epidemiological surveys: Oral Health Conditions in the State of Sao Paulo, 2002 and the Brazilian Oral Health Survey (SBBrasil) 2010. Secondary data for 5,782 (2002) and 369 (2010) 12-year-olds and 880 (2002) and 300 (2010) 15-to 19-year-olds were analyzed. Dental caries attack was evaluated using the DMFT (decayed, missing or fi lled teeth) index and the need for treatment verifi ed using the criteria proposed by the World Health Organization. The Signifi cant Caries Index was used to measure the severity of the decay in the tercile of the group with the highest prevalence of the disease. In order to analyze the results, the Chi-squared and Mann-Whitney tests were used, with a 5% signifi cance. Results: There was a decrease of 39.3 percentage points in the DMFT index for 12-year-olds (p < 0.001) and of 41.1 percentage points for the adolescents (p < 0.001) between 2002 and 2010, and an increase of around 161.0 and 303.0 percentage in the group which was free from dental caries respectively. The percentage of restored teeth decreased in both age groups, although the prevalence of dental caries did not change in the group more affected by dental caries. In the group with few dental caries, there was a decrease in the component 'tooth loss' for adolescents and increase in the component 'decayed teeth' for the 12-yearsold and the adolescents. There was an increase in the need for dental treatment in the group as a whole and in the group of 12-year-olds more affected by dental caries; and among the adolescents, the need for restoration on two or more surface decreased in the group as a whole and also in the group which suffered least from dental caries. Conclusions: The decreasing need for non-complex treatment in adolescents suggests that promotion and prevention activities are having a positive effect on this group. Moreover, the two epidemiological surveys in the state of Sao Paulo show improvements in oral health conditions in both age groups studied and calls for monitoring aimed also at the group least affected by dental caries.47SUPPL.35058Al-Haddad, K.A., Al-Hebshi, N.N., Ak'hali, M.S., Oral health status and treatment needs among school children in Sana'a City, Yemen (2010) Int J Dent Hyg., 8 (2), pp. 80-85. , DOI: 10.1111/j.1601-5037.2009.00398.xArmfield, J.M., Spencer, A.J., Slade, G.D., Changing inequalities in the distribution of caries associated with improving child oral health in Australia (2009) J Public Health Dent., 69 (2), pp. 125-134. , Pesquisa Nacional de Saúde Bucal (SBBrasil) DOI: 10.1111/j.1752-7325.2008.00110.xBagramian, R.A., Franklin, G.G., Anthony, R.V., The global increase in dental caries (2009) A pending public health crisis. Am J Dent., 22 (1), pp. 3-8Bratthall, D., Introducing the Signifi cant Caries Index together with a proposal for a new global oral health goal for 12-year-olds (2000) Int Dent J., 50 (6), pp. 378-384. , DOI: 10.1111/j.1875-595X.2000.tb00572.xCampus, G., Sacco, G., Cagetti, M., Abati, S., Changing trend of caries from 1989 to 2004 among 12-year old Sardinian children (2007) BMC Public Health., 7, p. 28Constante, H.M., Bastos, J.L., Peres, M.A., Trends in dental caries in 12-and 13-year-old schoolchildren from Florianópolis between 1971 and 2009 (2010) Braz J Oral Sci., 9 (3), pp. 410-414Davies, G.M., Jones, C.M., Monaghan, N., Morgan, M.Z., Neville, J.S., Pitts, N.B., The caries experience of 11 to 12 year-old children in Scotland and Wales and 12 year-olds in England in 2008-2009: reports of co-ordinated surveys using BASCD methodology (2012) Community Dent Health., 29 (1), pp. 8-13. , DOI: 10.1111/j.1471-4159.2012.07745.xDash, J.K., Sahoo, P.K., Bhuyan, S.K., Sahoo, S.K., Prevalence of dental caries and treatment needs among children of Cuttack (Orissa) (2002) J Indian Soc Pedo Prev Dent., 20 (4), pp. 139-143Ditmyer, M., Dounis, G., Mobley, C., Schwarz, E., Inequalities of caries experience in Nevada youth expressed by DMFT index vs (2011) Signifi cant Caries Index (SiC) over time. BMC Oral Health., 11, p. 12. , DOI: 10.1186/1472-6831-11-12Do, L.G., Distribution of caries in children: Variations between and within Populations (2012) J Dent Res., 91 (6), pp. 536-543. , DOI: 10.1177/0022034511434355Duraiswamy, P., Kumar, T.S., Dagli, R.J., Chandrakant, K.S., Dental caries experience and treatment needs of green marble mine laborers in Udaipur district, Rajasthan, India (2008) Indian J Dent Res., 19 (4), pp. 331-334. , DOI: 10.4103/0970-9290.44537Dye, B.A., Arevalo, O., Vargas, C.M., Trends in paediatric dental caries by poverty status in the United States, 1988-1994 and 1999-2004 (2010) Int J Paediatr Dent., 20 (2), pp. 132-143. , DOI: 10.1111/j.1365-263X.2009.01029.xFrias, A.C., Antunes, J.L.F., Narvai, P.C., Precisão e validade de levantamentos epidemiológicos em saúde bucal: cárie dentária na Cidade de São Paulo, 2002 (2004) Rev Bras Epidemiol., 7 (2), pp. 144-154. , DOI: 10.1590/S1415-790X2004000200004Gushi, L.L., Soares, M.C., Forni, T.I.B., Vieira, V., Wada, R.S., Sousa, M.L.R., Cárie dentária em adolescents de 15 a 19 anos de idade no Estado de São Paulo, Brasil, 2002 (2005) Cad Saude Publica., 21 (5), pp. 1383-1391. , DOI: 10.1590/S0102-311X2005000500010Gushi, L.L., Rihs, L.B., Soares, M.C., Forni, T.I.B., Vieira, V., Wada, R.S., Cárie dentária e necessidades de tratamento em adolescentes do estado de São Paulo, 1998 e 2002 (2008) Rev Saude Publica., 42 (3), pp. 480-486. , DOI: 10.1590/S0034-89102008005000015Kulkami, S.S., Deshpande, S.D., Caries prevalence and treatment needs in 11-15 year old children of Belgaum city (2002) J Indian Soc Prev Dent., 20 (1), pp. 12-15Martins, R.J., Garbin, C.A.S., Garbin, A.J.I., Moimaz, S.A.S., Saliba, O., Declínio da cárie em um município da região noroeste do Estado de São Paulo, Brasil, no período de 1998 a 2004 (2006) Cad Saude Publica., 22 (5), pp. 1035-1041. , DOI: 10.1590/S0102-311X2006000500016Mashoto, K.O., Astrom, A.N., Skeie, M.S., Masalu, J.R., Socio-demographic disparity in oral health among the poor: a cross sectional study of early adolescentes in Kilwa district, Tanzania (2010) BMC Oral Health., 10, p. 7. , DOI: 10.1186/1472-6831-10-7Narvai, P.C., Frazão, P., Roncalli, A.G., Antunes, J.L.F., Cárie dentária no Brasil: declínio, iniqüidade e exclusão social (2006) Rev Panam Salud Publica., 19 (6), pp. 385-393. , DOI: 10.1590/S1020-49892006000600004Piovesan, C., Mendes, F.M., Antunes, J.P.F., Ardenghi, T.M., Inequalities in the distribution of dental caries among 12-year-old Brazilian schoolchildren (2011) Braz Oral Res., 25 (1), pp. 69-75. , DOI: 10.1590/S1806-83242011000100012Rihs, L.B., Sousa, M.L.R., Cypriano, S., Abdalla, N.M., Desigualdades na distribuição da cárie dentária em adolescents de Indaiatuba (SP), 2004 (2010) Cienc Saude Coletiva., 15 (4), pp. 2173-2180. , DOI: 10.1590/S1413-81232010000400031Schulte, A.G., Momeni, A., Pieper, K., Caries prevalence in 12-year-old children from Germany (2006) Results of the 2004 national survey. 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    Necessary Optimality Conditions for Higher-Order Infinite Horizon Variational Problems on Time Scales

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    We obtain Euler-Lagrange and transversality optimality conditions for higher-order infinite horizon variational problems on a time scale. The new necessary optimality conditions improve the classical results both in the continuous and discrete settings: our results seem new and interesting even in the particular cases when the time scale is the set of real numbers or the set of integers.Comment: This is a preprint of a paper whose final and definite form will appear in Journal of Optimization Theory and Applications (JOTA). Paper submitted 17-Nov-2011; revised 24-March-2012 and 10-April-2012; accepted for publication 15-April-201
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