A cosmological concordance model with dynamical vacuum term

We demonstrate that creation of dark-matter particles at a constant rate implies the existence of a cosmological term that decays linearly with the Hubble rate. We discuss the cosmological model that arises in this context and test it against observations of the first acoustic peak in the cosmic microwave background (CMB) anisotropy spectrum, the Hubble diagram for supernovas of type Ia (SNIa), the distance scale of baryonic acoustic oscillations (BAO) and the distribution of large scale structures (LSS). We show that a good concordance is obtained, albeit with a higher value of the present matter abundance than in the \Lambda CDM model. We also comment on general features of the CMB anisotropy spectrum and on the cosmic coincidence problem.Comment: Revised version. Accepted for publication in Physics Letters

Update On Nonsurgical, Ultraconservative Approaches To Treat Effectively Non-cavitated Caries Lesions In Permanent Teeth

Dental caries on tooth surfaces is still a problem in many industrialized countries. For many years, dentistry was influenced by a mechanical approach characterized by the use of high-speed rotary cutting instruments, and dentists predominantly used surgical methods to address caries. This included radical removal of diseased portions of the tooth, along with material-driven geometric extensions to areas that were assumed to be caries-resistant. This concept of extension for prevention was introduced by G. V. Black and influenced dentists for more than 120 years. Recently, a new paradigm of operative conservatism, sometimes referred to as "minimally invasive dentistry," has gained popularity. This paradigm is designed to promote maximum preservation of healthy dental structures over a lifetime. The aim of this review is to discuss the efficacy of current nonsurgical treatments for non-cavitated caries lesions in permanent teeth. Based on results obtained from clinical trials, this review evaluates treatments such as consumption of CPP-ACP added gums, resin infiltration and fissure sealing. Although in a few cases an invasive approach is needed to arrest caries progression, the non-surgical approach generally provides potential benefits that include conserving structure by delaying intervention or minimizing the operative procedure. All current non-invasive methods are effective in treating non-cavitated caries lesions. The adoption of non-invasive approaches in the management of these lesions can preserve dental tissues, thus increasing tooth longevity.52229236Bader, J.D., Shugars, D.A., The evidence supporting alternative management strategies for early occlusal caries and suspected occlusal dentinal caries (2006) J Evid Base Dent Pract, 6, pp. 91-100Beauchamp, J., Caufield, P.W., Crall, J.J., Evidence-based clinical recommendations for the use of pit-and-fissure sealants: a report of the America Dental Association council on scientific affairs (2009) Dent Clin N Am, 53, pp. 131-147Paris, S., Meyer-Lueckel, H., Kielbassa, A.M., Resin infiltration of natural caries lesions (2007) J Dent Res, 86, pp. 662-666Morgan, M.V., Adams, G.G., Bailey, D.L., The anticariogenic effect of sugar-free gum containing CPP-ACP nanocomplexes on approximal caries determined using digital bitewing radiography (2008) Caries Res, 42, pp. 171-184Kuisch, V.K., Dental caries: a new look at an old disease (2009) Inside Dent, 5, pp. 60-65Feacherstone, J.D., Dental caries: a dynamic disease process (2008) Aust Dent J, 53, pp. 286-291Diefenderfer, K.E., Stahl, J., Caries remineralization therapy: implications for dental readiness (2008) Mil Med, 173, pp. 48-50Maltz, M., Jardim, J.J., Alves, L.R., Health promotion and dental caries (2010) Braz Oral Res, 24 (SPEC ISSUE 1), pp. 18-25Sharma, S., Kugel, G., Amorphous calcium phosphate sealants - the potential to remineralize (2009) Inside Dent, 5Bartlett, D.W., Bureau, G.P., Anggiansah, A., Evaluation of the pH of a new carbonated soft drink beverage: an in vivo investigation (2003) J Prosthodont, 12, pp. 21-25Khan, A.A., Jain, S.K., Shrivastav, A., Prevalence of dental caries among the population of Gwalior (India) in relation of different associated factors (2008) Eur J Dent, 2, pp. 81-85Kugel, G., Arsenault, P., Papas, A., Treatment modalities for caries management, including a new resin infiltration system (2009) Compend Contin Educ Dent, 30 (SPEC ISSUE 3), pp. 1-10Kidd, E.A., Fejerskov, O., What Constitutes Dental Caries? Histopathology of carious enamel and dentin related to the action of cariogenic biofilms (2004) J Dent Res, 83 (SPEC ISSUE C), pp. C35-C38Mount, G.J., A new paradigm for operative dentistry (2007), 52, pp. 264-270Black, G.V., Operative Dentistry (1908) Chicago: Medico-Dental Publishing, 121Massler, M., Changing concepts in the treatment of carious lesions (1967) Br Dent J, 123, pp. 547-548ten Cate, J.M., Duijsters, P.P., Alternating demineralization and remineralization of artificial enamel lesions (1982) Caries Res, 16, pp. 201-210Featherstone, J.B., The continuum of dental caries - evidence for a dynamic disease process (2004) J Dent Res, 83 (SPEC ISSUE C), pp. 39-42Featherstone, J.B., Clinical aspects of the de/remineralization of teeth (1995) Adv Dent Res, 9, pp. 1-340. , edBrännström, M., (1982) Dentin and pulp in restorative dentistry, , London: Wolfe Medical Publications LtdReynolds, E.C., Walsh, I.J., Additional aids to the remineralization of tooth structure (2005) Preservation and restoration of tooth structure, pp. 111-118. , Mount GJ, Hume WR, eds., 2 nd edn. Brisbane: Knowledge Books and SoftwareNgo, H.C., Mount, G.J., McIntyre, J., Chemical exchange between glass-ionomer restorations and residual carious dentine in permanent molar: an in vivo study (2006) J Dent, 34, pp. 608-613Pitts, N.B., Modern concepts of caries measurement (2004) J Dent Res, 83 (SPEC ISSUE C), pp. 43-47McComb, D., Systematic review of conservative operative caries management strategies (2001) J Dent Educ, 65, pp. 1154-1161Zero, D.T., Dentifrices, mouthwashes, and remineralization/ caries arrestment strategies (2006) BMC Oral Health, 6, pp. S9Mjör, I.A., Holst, D., Eriksen, H.M., Caries and restoration prevention (2008) J Am Dent Assoc, 139, pp. 565-570Reynolds, E.C., Cain, C.J., Shen, P., Retention in plaque and remineralization of enamel lesions by various forms of calcium in a mouthrinse or sugar-free chewing gum (2003) J Dent Res, 82, pp. 206-211Manton, D.J., Walker, G.D., Cai, F., Cochrane, N.J., Shen, P., Reynolds, E.C., Remineralization of enamel subsurface lesions in situ by the use of three commercially available sugar-free gums (2008) Int J Paediatr Dent, 18, pp. 284-290Walker, G.D., Cai, F., Shen, P., Casein phosphopeptideamorphous calcium phosphate incorporated into sugar confections inhibit the progression of enamel subsurface lesions in situ (2010) Caries Res, 44, pp. 33-40Paris, S., Meyer-Lueckel, H., Inhibition of caries progression by resin infiltration in situ (2010) Caries Res, 44, pp. 47-54Paris, S., Meyer-Lueckel, H., Colfen, H., Resin infiltration of artificial enamel caries lesions with experimental light curing resins (2007) Dent Mater J, 26, pp. 582-588Paris, S., Hopfenmuller, W., Meyer-Lueckel, H., Resin infiltration of caries lesion: an efficacy randomized trial (2010) J Dent Res, , doi: 10. 1177/0022034510369289Martignon, S., Ekstrand, K.R., Ellwood, R., Efficacy of sealing proximal early active lesions: an 18-month clinical study evaluated by conventional and subtraction radiography (2006) Caries Res, 40, pp. 382-388Phark, J.H., Duarte Jr., S., Meyer-Lueckel, H., Caries infiltration with resins: a novel treatment option for interproximal caries (2009) Compend Contin Educ Dent, 30 (SPES ISSUE 3), pp. 13-17ten Cate, J.M., Remineralization of deep enamel dentin caries lesions (2008) Aust Dent J, 53, pp. 281-285Doméjean-Orliaguet, S., Tubert-Jeannin, S., Riordan, P.J., French dentists' restorative treatment decisions (2004) Oral Health Prev Dent, 2, pp. 125-131Traebert, J., Wesoloski, C.I., Lacerda, J.T., Threshold of restorative decision in dental caries treatment among dentists from small Brazilian cities (2007) Oral Health Prev Dent, 5, pp. 131-135Mertz-Fairhurst, E.J., Curtis-Jr., J.W., Ergle, J.W., Ultraconservative and cariostatic sealed restorations: results at year 10 (1998) J Am Dent Assoc, 129, pp. 55-66Alves, L.S., Fontanella, V., Damo, A.C., Qualitative and quantitative radiographic assessment of sealed carious dentin: a 10-year prospective study (2010) Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 109, pp. 135-141Maltz, M., Oliveira, E.F., Fontanella, V., A clinical, microbiologic, and radiographic study of deep lesions, after incomplete caries removal (2002) Quintessence Int, 33, pp. 151-159Weerheijm, K.L., van Amerongen, W.E., Eggink, C.O., The clinical diagnosis of occlusal caries: a problem (1989) ASDC J Dent Child, 56, pp. 196-200Murdoch-Kinck, C., McLean, M., Minimally invasive dentistry (2003) J Am Dent Assoc, 134, pp. 87-95Brostck, A., Early diagnosis and minimally invasive treatment of occlusal caries - a clinical approach (2004) Oral Health Prev Dent, 2 (SUPPL. 1), pp. 313-319Borges, B.C., Campos, G.B., da Silveira, A.D., de Lima, K.C., Pinheiro, I.V., Efficacy of a pit and fissure sealant in arresting dentin non-cavitated caries: a 1-year follow-up, randomized, single-blind, controlled clinical trial (2010) Am J Dent, 23, pp. 311-316Silveira, A.D., Borges, B.C., Varela, H.A., Progression of non-cavitated lesions in dentin through a nonsurgical approach: a preliminary 12-month clinical observation (2010) Eur J Dent, , in pressUysal, T., Amasyali, M., Koyuturk, A.E., Efficiency of amorphous calcium phosphate-containing orthodontic composite and resin modified glass ionomer cement on demineralization evaluated by a new laser fluorescence device (2009) Eur J Dent, 3, pp. 127-13

Epidemiological status of bovine brucellosis in the Federal District, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Distrito Federal (DF). No total foram amostrados 2.019 animais, provenientes de 278 propriedades. Em cada propriedade visitada aplicou-se um questionário epidemiológico para verificar o tipo de exploração e as práticas de criação e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo utilizado foi o da triagem com o teste do antígeno acidificado tamponado e a confirmação dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo quando pelo menos um animal foi reagente às duas provas sorológicas. A prevalência no DF foi de 2,5% [1,0-5,1%] para propriedades e de 0,16% [0,04-0,28%] para animais. Em razão dos resultados encontrados, que permitem pensar em estratégias de erradicação, recomenda-se que o DF intensifique o diagnóstico de brucelose, tanto na forma de testes sorológicos sistemáticos como pela introdução de mecanismos de detecção rápida em laticínios, em ambos os casos a fim de aumentar o número de propriedades certificadas como livres da doença e melhorar a sensibilidade do sistema de vigilância ativa.A study to characterize the epidemiological status of brucellosis was carried out in the Federal District of Brazil. A total of 2,019 serum samples from 278 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal Test (RBT), and all positive sera were re-tested by the 2-mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. Herd prevalence was estimated as 2.5% [1.0-5.1%] whereas animal prevalence was 0.16% [0.04-0.28%]. Given these results, that may warrant the implementation of eradication strategies, there is a case for intensifying the serological testing in the Federal District, coupled with the introduction of rapid detection methods by the dairy industries, with a view to increasing the number of accredited free herds and improving the sensitivity of the surveillance system..FAPESPCNPqSEAP-DFMAPA Ministério da Agricultura, Pecuária e Abasteciment

Black hole thermodynamical entropy

As early as 1902, Gibbs pointed out that systems whose partition function diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs (BG) theory. Consistently, since the pioneering Bekenstein-Hawking results, physically meaningful evidence (e.g., the holographic principle) has accumulated that the BG entropy $S_{BG}$ of a $(3+1)$ black hole is proportional to its area $L^2$ ($L$ being a characteristic linear length), and not to its volume $L^3$. Similarly it exists the \emph{area law}, so named because, for a wide class of strongly quantum-entangled $d$-dimensional systems, $S_{BG}$ is proportional to $\ln L$ if $d=1$, and to $L^{d-1}$ if $d>1$, instead of being proportional to $L^d$ ($d \ge 1$). These results violate the extensivity of the thermodynamical entropy of a $d$-dimensional system. This thermodynamical inconsistency disappears if we realize that the thermodynamical entropy of such nonstandard systems is \emph{not} to be identified with the BG {\it additive} entropy but with appropriately generalized {\it nonadditive} entropies. Indeed, the celebrated usefulness of the BG entropy is founded on hypothesis such as relatively weak probabilistic correlations (and their connections to ergodicity, which by no means can be assumed as a general rule of nature). Here we introduce a generalized entropy which, for the Schwarzschild black hole and the area law, can solve the thermodynamic puzzle.Comment: 7 pages, 2 figures. Accepted for publication in EPJ

Structural and doping effects in the half-metallic double perovskite A2A_2CrWO6_6

he structural, transport, magnetic and optical properties of the double perovskite $A_2$CrWO$_6$ with $A=\text{Sr, Ba, Ca}$ have been studied. By varying the alkaline earth ion on the $A$ site, the influence of steric effects on the Curie temperature $T_C$ and the saturation magnetization has been determined. A maximum $T_C=458$ K was found for Sr$_2$CrWO$_6$ having an almost undistorted perovskite structure with a tolerance factor $f\simeq 1$. For Ca$_2$CrWO$_6$ and Ba$_2$CrWO$_6$ structural changes result in a strong reduction of $T_C$. Our study strongly suggests that for the double perovskites in general an optimum $T_C$ is achieved only for $f \simeq 1$, that is, for an undistorted perovskite structure. Electron doping in Sr$_2$CrWO$_6$ by a partial substitution of Sr$^{2+}$ by La$^{3+}$ was found to reduce both $T_C$ and the saturation magnetization $M_s$. The reduction of $M_s$ could be attributed both to band structure effects and the Cr/W antisites induced by doping. Band structure calculations for Sr$_2$CrWO$_6$ predict an energy gap in the spin-up band, but a finite density of states for the spin-down band. The predictions of the band structure calculation are consistent with our optical measurements. Our experimental results support the presence of a kinetic energy driven mechanism in $A_2$CrWO$_6$, where ferromagnetism is stabilized by a hybridization of states of the nonmagnetic W-site positioned in between the high spin Cr-sites.Comment: 14 pages, 10 figure

Trabalho, terra e geração de renda em três décadas de reflorestamentos no alto Jequitinhonha.

A partir dos anos 1970, as chapadas do Alto Jequitinhonha, localizadas no nordeste de Minas Gerais, até então áreas de uso comum de agricultores familiares, foram plantadas com eucaliptos. O objetivo deste artigo é comparar os efeitos do reflorestamento sobre a estrutura fundiária, valor da produção agrícola e ocupação rural com os efeitos da produção agrícola familiar sobre essas mesmas variáveis na microrregião homogênea de Capelinha, no Alto Jequitinhonha. Tal microrregião foi escolhida para o estudo por ser a área de maior concentração de eucaliptais da região. Foram utilizados dados secundários dos Censos do IBGE para os anos de 1970, 1980, 1985 e 1996, além de dados secundários de pesquisas realizadas sobre a região em questão, incluindo entrevistas com dirigentes de empresas e lideranças sindicais. O artigo conclui que, em trinta anos, o reflorestamento concentrou terras e criou um número reduzido de empregos; a agricultura familiar, ao contrário, teve suas áreas de terras comprimidas e super-exploradas em decorrência da perda das chapadas, mas continuou sendo a principal responsável pela geração de ocupações e rendas na região