993 research outputs found
Métodos multivariados aplicados ao melhoramento genético do feijoeiro visando ao aumento da tolerância ao estresse osmótico e biofortificação de grãos
O feijoeiro (Phaseolus vulgaris L.) é uma cultura agrÃcola muito importante economicamente e nutricionalmente para a população brasileira e necessita de metodologias simples e eficazes que auxiliem o processo de melhoramento genético. As técnicas empregadas devem minimizar os efeitos indesejáveis da multicolinearidade entre as caracterÃsticas estudadas durante o processo de seleção. A produção de sementes de feijão, normalmente, é limitada pela escassez hÃdrica e solos salinos. No entanto, devido a grande variabilidade genética, caracterÃstica da espécie, é possÃvel encontrar materiais genéticos mais tolerantes a esses estresses osmóticos. A germinação e o desenvolvimento inicial da plântula são fases crÃticas e desta maneira é importante selecionar os matérias genéticos mais tolerantes nestas fases. Além de selecionar genótipos tolerantes é necessário selecionar materiais genéticos que sejam ricos nutricionalmente, principalmente, em relação à composição mineralógica. Os principais objetivos almejados com este trabalho foram reduzir a multicolinearidade e selecionar genótipos para a tolerância ao estresse osmótico e a biofortificação dos grãos do feijoeiro, com base nos valores genéticos. Desta maneira, foram utilizadas duas técnicas para reduzir a influência da multicolinearidade: o descarte de variáveis redundantes pelas variáveis canônicas, e o uso das análises de fatores para reduzir o número de variáveis. As variáveis analisadas foram: porcentagem de germinação e de plântulas normais, tempo médio de germinação, Ãndice de velocidade de germinação, comprimentos de raiz e de hipocótilo, massas seca de raiz e da parte aérea, razão raiz/parte aérea e o produto da porcentagem de plântulas normais pelo comprimento das plântulas. Avaliou-se também a composição mineralógica dos grãos em relação à concentração de cálcio, ferro, zinco, potássio, magnésio, manganês e fósforo. Adicionalmente, para estimar os parâmetros e os valores genéticos realizou-se análise via modelos mistos, utilizando-se a técnica de REML/BLUP. Os genótipos foram selecionados com base da média genética, estabilidade e adaptabilidade, utilizando-se a técnica da média harmônica da performance relativa dos valores genéticos. Os genótipos que apresentaram as maiores tolerâncias, adaptabilidade e estabilidade quanto aos estresses osmóticos foram: CNFC 15466, CNFC 15462, CNFC 15630, BRS Valente, Capixaba Precoce, CNFP 15290, CNFP 15292 e CNFP 15302. Enquanto os genótipos mais ricos e divergentes geneticamente do grupo comercial carioca foram: CNFC 15475 e CNFC 15625, e do grupo comercial preto foram: CNFP 15310 e CNFP 15304. Conclui-se que a utilização de técnicas multivariadas facilita a seleção de genótipos promissores como parentais na formação de linhagens tolerantes ao estresse osmótico e biofortificados.
Palavras-chave: feijoeiro comum; seleção de genótipos; estresse hÃdrico e salino; multicolinearidade; composição mineral
Quark propagator in a covariant gauge
Using mean--field improved gauge field configurations, we compare the results
obtained for the quark propagator from Wilson fermions and Overlap fermions on
a \3 lattice at a spacing of fm.Comment: 5 pages, 8 figures, talk given by F.D.R. Bonnet at LHP 2001 workshop,
Cairns, Australi
The electric dipole moment of the neutron from 2+1 flavor lattice QCD
We compute the electric dipole moment d_n of the neutron from a fully
dynamical simulation of lattice QCD with 2+1 flavors of clover fermions and
nonvanishing theta term. The latter is rotated into the pseudoscalar density in
the fermionic action using the axial anomaly. To make the action real, the
vacuum angle theta is taken to be purely imaginary. The physical value of d_n
is obtained by analytic continuation. We find d_n = -3.8(2)(9) x 10^{-16}
[theta e cm], which, when combined with the experimental limit on d_n, leads to
the upper bound theta < 7.6 x 10^{-11}.Comment: 12 pages, 8 figures, matches PRL published versio
SPh functionalized bridging-vinyliminium diiron and diruthenium complexes
The SPh functionalized vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(SPh)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C6H4OMe, R′ = Me, 2c; R = Xyl, R′ = CH2OH, 2d; R = Me, R′ = CH2OH, 2e; Xyl = 2,6-Me2C6H3] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(H)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (1a–e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(SPh)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2f) was obtained from the corresponding vinyliminium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(H)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe2{μ-CN(Me)(4-C6H4OMe)}(SPh)(μ-CO)(CO)(Cp)2] (3). The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies
The adaptation of lipid profile of human fibroblasts to alginate 2D films and 3D printed scaffolds
Background: The investigation of the interactions between cells and active materials is pivotal in the emerging 3D printing-biomaterial application fields. Here, lipidomics has been used to explore the early impact of alginate (ALG) hydrogel architecture (2D films or 3D printed scaffolds) and the type of gelling agent (CaCl2 or FeCl3) on the lipid profile of human fibroblasts. Methods: 2D and 3D ALG scaffolds were prepared and characterized in terms of water content, swelling, mechanical resistance and morphology before human fibroblast seeding (8 days). Using a liquid chromatography-triple quadrupole-tandem mass spectrometry approach, selected ceramides (CER), lysophosphatidylcholines (LPC), lysophosphatidic acids (LPA) and free fatty acids (FFA) were analyzed. Results: The results showed a clear alteration in the CER expression profile depending of both the geometry and the gelling agent used to prepare the hydrogels. As for LPCs, the main parameter affecting their distribution is the scaffold architecture with a significant decrease in the relative expression levels of the species with higher chain length (C20 to C22) for 3D scaffolds compared to 2D films. In the case of FFAs and LPAs only slight differences were observed as a function of scaffold geometry or gelling agent. Conclusions: Variations in the cell membrane lipid profile were observed for 3D cell cultures compared to 2D and these data are consistent with activation processes occurring through the mutual interactions between fibroblasts and ALG support. These unknown physiologically relevant changes add insights into the discussion about the relationship between biomaterial and the variations of cell biological functions
Primary Absence of Type II Endoleak is A Positive Prognostic Factor against the Risk of Late Conversion of EVAR for AAA
Introduction: The aim of this study is to analyze 12 late conversion to open surgery after Endovascular Repair of
Abdominal Aortic Aneurysms (EVAR) while comparing the follow up of these cases to that of the definitely
successful procedures (absence of surgical conversion, type I or III endoleaks, or presence of type II endoleaks
without any aneurysmal sac enlargement) .
Methods: From a series of over 300 EVAR procedures performed at our department we have selected 215 cases
with a follow up ≥ 6 month and primary technical success (successful deployment of the devices and discharge of
patients without neither type I nor III endoleaks). Based on the final data recorded at the end of the follow up (mean+
IQR: 38.16 months + 41), these cases were divided into three groups: group 1, with 12 cases (5.6%) which needed
surgical conversion in a later stage (5 to 55 months from EVAR); group 2, with 39 cases (18.1%) with type II
endoleaks without aneurysmal sac enlargement; group 3, with 164 cases (76.5%) without endoleaks. The groups
were compared in relation to the following parameters: a) personal data and common atherogenic risk factor, b)
diameter of the aneurysm, c) kind of the proximal fixation of the endograft (suprarenal or infrarenal), d) presence of
endoleaks at the first postoperative check. We have compared the data from the three groups and we have
analyzed them with chi-square test (Χ2).
Results: Personal data and common atherogenic risk factor have proved no significant difference among the
three groups. The incidence of the other three parameters of group 1 was compared with the incidence of these in
groups 2 and 3: the mean pre-operative diameter of the aneurysm results 51 mm in group 1, 54 mm in group 2 and
55 mm in group 3 (not significant); suprarenal fixation of the prosthesis accounts for 50% in group 1, 51% in group 2
and 60% in group 3 (not significant); presence of type II endoleak at the first post-operative check was 41.6% in
group 1, 56.4% in group 2 (not significant) and 9.7% in group 3 (p<0.001, compared to groups 1 and 2).
Conclusion: In the EVAR procedures with primary technical success, the absence of type II endoleak at the first
post-operative check represents a favorable prognostic factor against the risk of late conversion to open repair.
Personal data, common atherogenic risk factor, diameter of the aneurysm and fixing type of the prosthesis don’t
seem to influence the onset of this complication
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