Thin-shell wormholes in dilaton gravity

In this work we construct charged thin-shell Lorentzian wormholes in dilaton gravity. The exotic matter required for the construction is localized in the shell and the energy conditions are satisfied outside the shell. The total amount of exotic matter is calculated and its dependence with the parameters of the model is analysed.Comment: 7 pages, 1 figure; v2: shortened and improved. Accepted for publication in Physical Review

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

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

Resumo

In Vivo Length Changes Between the Attachments of the Medial Patellofemoral Complex Fibers in Knees With Anatomic Risk Factors for Patellar Instability

Background: Medial patellofemoral complex (MPFC) reconstruction plays an important role in the surgical treatment of patellar instability. Anatomic reconstruction is critical in re-creating the native function of the ligament, which includes minimizing length changes that occur in early flexion. Anatomic risk factors for patellar instability such as trochlear dysplasia, patella alta, and increased tibial tuberosity to trochlear groove (TT-TG) distance have been shown to influence the function of the MPFC graft in cadaveric studies, but the native length change patterns of the MPFC fibers in knees with anatomic risk factors have not been described. Purpose: To describe the in vivo length changes of the MPFC fibers in knees with anatomic risk factors for patellar instability and identify the optimal attachment sites for MPFC reconstruction. Study Design: Controlled laboratory study. Methods: Dynamic computed tomography imaging was performed on the asymptomatic knee in patients with contralateral patellar instability. Three-dimensional digital knee models were created to assess knees between 0° and 50° of flexion in 10° increments. MPFC fiber lengths were calculated at each flexion angle between known anatomic attachment points on the extensor mechanism (quadriceps tendon, MPFC midpoint [M], and patella) and femur (1, 2, and 3, representing the proximal to distal femoral footprint). Changes in MPFC fiber length were compared for each condition and assessed for their relationships to morphologic risk factors (trochlear depth, Caton Deschamps Index [CDI], and TT-TG distance). Results: In 22 knees, native MPFC fibers were found to be longer at 0° than at 20° to 50° of flexion. Length changes observed between 0° and 50° increased with the number of risk factors present. In the central fibers of the MPFC (M-2), 1.7% ± 3.1% length change was noted in knees with no anatomic risk factors, which increased to 5.6% ± 4.6%, 17.0% ± 6.4%, and 26.7% ± 6.8% in the setting of 1, 2, and 3 risk factors, respectively. Nonanatomic patella-based attachments were more likely to demonstrate unfavorable length change patterns, in which length was greater at 50° than 0°. In patellar attachments, an independent relationship was found between increasing length changes and TT-TG distance, while in quadriceps tendon attachments, a trend toward a negative relationship between length changes and CDI was noted. All configurations demonstrated a strong relationship between percentage change in length and number of morphologic risk factors present, with the greatest influence found in patella-based attachments. Conclusion: The MPFC fibers demonstrated increased length changes in knees when a greater number of morphological risk factors for patellar instability were present, which worsened in the setting of nonanatomic configurations. This suggests that the function of the intact MPFC in patients with anatomic risk factors may not reflect previously described findings in anatomically normal knees. Further studies are needed to understand the pathoanatomy related to these changes, as well as the implications for graft placement and assessment of length changes during MPFC reconstruction techniques. Clinical Relevance: MPFC length change patterns vary based on the number of morphologic risk factors for patellar instability present and should be considered during reconstructive procedures.</p

Manual de qualidade laboratorial: laboratório de análises de sementes florestais (LASF).

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A Nonsingular Brans Wormhole: An Analogue to Naked Black Holes

In a recent paper, we showed the Jordan frame vacuum Brans Class I solution provided a wormhole analogue to Horowitz-Ross naked black hole in the wormhole range -3/2<{\omega}<-4/3. Thereafter, the solution has been criticized by some authors that, because of the presence of singularity in that solution within this range, a wormhole interpretation of it is untenable. While the criticism is correct, we show here that (i) a singularity-free wormhole can actually be obtained from Class I solution by performing a kind of Wick rotation on it, resulting into what Brans listed as his independent Class II solution (ii) the Class II solution has all the necessary properties of a regular wormhole in a revised range -2<{\omega}<-3/2 and finally, (iii) naked black holes, as described by Horowitz and Ross, are spacetimes where the tidal forces attain their maxima above the black hole horizon. We show that in the non-singular Class II spacetime this maxima is attained above the throat and thus can be treated as a wormhole analogue. Some related issues are also addressed.Comment: 20 pages, 4 figure