Probing global aspects of a geometry by the self-force on a charge: Spherical thin-shell wormholes

The self-interaction for a static point charge in the space-time of a thin-shell wormhole constructed connecting two identical Schwarzschild geometries is calculated in a series expansion. The electrostatic self-force is evaluated numerically. It is found to be attractive towards the throat except for some values of the throat radius proximate to the value of the Schwarzschild horizon for which the force is repulsive or attractive depending on the position of the charge. The result differs from the self-force in the space-time of the Schwarzschild black hole, where it is always repulsive from the center. Although these wormhole and black hole geometries are locally indistinguishable, the different topologies of both backgrounds are manifested in the electrostatic field of a point charge.Comment: 17 pages, 4 figue

Differences in reactivation of tuberculosis induced from anti-tnf treatments are based on bioavailability in granulomatous tissue

The immune response to Mycobacterium tuberculosis (Mtb) infection is complex. Experimental evidence has revealed that tumor necrosis factor (TNF) plays a major role in host defense against Mtb in both active and latent phases of infection. TNF-neutralizing drugs used to treat inflammatory disorders have been reported to increase the risk of tuberculosis (TB), in accordance with animal studies. The present study takes a computational approach toward characterizing the role of TNF in protection against the tubercle bacillus in both active and latent infection. We extend our previous mathematical models to investigate the roles and production of soluble (sTNF) and transmembrane TNF (tmTNF). We analyze effects of anti-TNF therapy in virtual clinical trials (VCTs) by simulating two of the most commonly used therapies, anti-TNF antibody and TNF receptor fusion, predicting mechanisms that explain observed differences in TB reactivation rates. The major findings from this study are that bioavailability of TNF following anti-TNF therapy is the primary factor for causing reactivation of latent infection and that sTNF-even at very low levels-is essential for control of infection. Using a mathematical model, it is possible to distinguish mechanisms of action of the anti-TNF treatments and gain insights into the role of TNF in TB control and pathology. Our study suggests that a TNF-modulating agent could be developed that could balance the requirement for reduction of inflammation with the necessity to maintain resistance to infection and microbial diseases. Alternatively, the dose and timing of anti-TNF therapy could be modified. Anti-TNF therapy will likely lead to numerous incidents of primary TB if used in areas where exposure is likely. © 2007 Marino et al

Quantitative Trait Loci mapping for sugar-related traits in sweet sorghum based on high-density SNP markers : P0187

Sweet sorghum, a C4 tropical grass, is becoming an important bioenergy crop. Characterizing quantitative trait loci (QTL) controlling sugar content in its stem can lead to the identification of target regions for molecular breeding programs. These QTLs may be conserved in related species such as sugarcane, expanding their potential usefulness for bioenergy production. In this study, 223 recombinant inbred lines (RILs) derived from the sweet sorghum parents, Brandes and Wray, were genotyped-by-sequencing (GBS). A lattice experiment with three replicates was established for evaluating three sugar related traits: soluble solids content (BRIX, in °Brix), sucrose content (POL, in %), and reducing sugars (RSU, in %). Phenotypic analysis and QTL scanning were conducted using mixed and general linear models approaches, using the softwares GenStat and TASSEL, respectively. GBS provided wide genome coverage, with ~1200 single-nucleotide polymorphisms (SNPs) per chromosome. Major QTLs were detected for BRIX and POL on chromosome 3, and for RSU on chromosome 4, explaining up to 20.8%, 18.9% and 15.5% of the phenotypic variance. False discovery rate correction suggested that QTLs were co-located on chromosome 1 for all traits as well. The QTLs identified here will be further investigated for possible use in marker-assisted selection targeting biofuel production in sweet sorghum. (Résumé d'auteur

La mutualità nel caregiving: una revisione della letteratura

Mutuality, considered the feeling of intimacy and the positive relationship between a caregiver and a arereceiver, is gaining an increasing interest in the international research arena, on the light of the socio-demographic changes and the increase in chronic degenerative diseases. The purpose of this article is to make a critical analysis of the literature on mutuality in order to identify its predictors and outcomes. A literature review was performed with the following databases: PubMed, CINAHL, PsycInfo, ASSIA and Pciological Abstract. Twenty articles were selected. From the critical analysis of the literature mutuality emerges as key variable in the process of caregiving and in the mental and physical health of the caregiver and carereceiver. In caregivers, high levels of mutuality are associated with less stress, depression and burden and a better quality of life and perceived health; in patients, high mutuality improves the recovery process from an illness, reduces anxiety and depression and improves the quality of life. Future studies aimed at the study of this variable also in the Italian population could support the development of programs to improve the quality of life of caregivers and carereceiver

Caracterização genética e química de germoplasma de imbuia do BAG de Três Barras, SC.

Um banco de germoplasma de imbuia foi instalado por equipe da Embrapa Florestas, em Três Barras, SC, em 2008,. com as populações coletadas em Colombo, Canoinhas e Caçador no ano de 2004. A população de Canoinhas conta com 28 progênies, sendo 6 selecionadas e 22 não selecionadas; Colombo: 26 progênies, sendo 22 selecionadas e 4 não selecionadas e Caçador: 25 progênies, sendo 19 selecionadas e 06 não selecionadas. Estudos preliminares foram realizados para verificar as potencialidades da espécie para uso futuro. Foi realizada a caracterização genética na fase de sementes e de mudas, bem como a caracterização química das sementes. A composição centesimal aproximada das sementes, quanto à umidade, cinzas, lipídios e proteínas, foi determinada pelos métodos descritos nas Normas Analíticas do Instituto Adolfo Lutz: perda por dessecação, resíduo por incineração, extração direta com éter etílico em aparelho tipo Soxhlet, processo de digestão Kjeldahl, respectivamente. A análise química mostrou que, na composição dos ácidos graxos, o óleo da semente de imbuia é altamente saturado (67 % de ácidos graxos saturados), apresentando como componente principal o ácido láurico (11,49 %). Foi evidenciada uma maior quantidade de proteína na polpa em relação aos demais componentes bioquímicos estudados. O alto teor de ácido láurico favorece seu uso na indústria de cosméticos e sabões, se eliminadas eventuais substâncias nocivas à saúde. As estimativas de parâmetros genéticos e a seleção genética foram realizadas pela metodologia dos modelos lineares mistos (procedimento REML/BLUP. No prémelhoramento da imbuia, concluiu-se que a maior variabilidade genética dentro de populações constitui indicação de predominância de alogamia na espécie, que a herdabilidade média, coeficiente de variação genético individual e os ganhos genéticos obtidos indicam o potencial destas populações para melhoramento genético e que os melhores genitores pertencem à população de Colombo, seguida da população de Canoinhas

Time asymmetries in quantum cosmology and the searching for boundary conditions to the Wheeler-DeWitt equation

The paper addresses the quantization of minisuperspace cosmological models by studying a possible solution to the problem of time and time asymmetries in quantum cosmology. Since General Relativity does not have a privileged time variable of the newtonian type, it is necessary, in order to have a dynamical evolution, to select a physical clock. This choice yields, in the proposed approach, to the breaking of the so called clock-reversal invariance of the theory which is clearly distinguished from the well known motion-reversal invariance of both classical and quantum mechanics. In the light of this new perspective, the problem of imposing proper boundary conditions on the space of solutions of the Wheeler-DeWitt equation is reformulated. The symmetry-breaking formalism of previous papers is analyzed and a clarification of it is proposed in order to satisfy the requirements of the new interpretation.Comment: 25 pages, 1 figur