4,399 research outputs found
Occurrence of Leucophanes(Leucobryaceae, Bryopsida) in Brazilian Amazonia
The first occurrence of Leucophanes brasiliense BROTH. and L. calymperatum C. MUELL. (Leucobryaceae, Bryopsida) in Brazilian Amazonia, is herein reported. These species grow on tree trunks and on lianas in humid forests. As the specimens were not fertile, identifications were based on morphological characters of the gametophytes. Illustrations of these specimens, necessary for taxonomical identification, are included
Conformal Transformations of the Wigner Function and Solutions of the Quantum Corrected Vlasov Equation
We study conformal properties of the quantum kinetic equations in curved
spacetime. A transformation law for the covariant Wigner function under
conformal transformations of a spacetime is derived by using the formalism of
tangent bundles. The conformal invariance of the quantum corrected Vlasov
equation is proven. This provides a basis for generating new solutions of the
quantum kinetic equations in the presence of gravitational and other external
fields. We use our method to find explicit quantum corrections to the class of
locally isotropic distributions, to which equilibrium distributions belong. We
show that the quantum corrected stress--energy tensor for such distributions
has, in general, a non--equilibrium structure. Local thermal equilibrium is
possible in quantum systems only if an underlying spacetime is conformally
static (not stationary). Possible applications of our results are discussed.Comment: 30 page
On paraquaternionic submersions between paraquaternionic K\"ahler manifolds
In this paper we deal with some properties of a class of semi-Riemannian
submersions between manifolds endowed with paraquaternionic structures, proving
a result of non-existence of paraquaternionic submersions between
paraquaternionic K\"ahler non locally hyper paraK\"ahler manifolds. Then we
examine, as an example, the canonical projection of the tangent bundle, endowed
with the Sasaki metric, of an almost paraquaternionic Hermitian manifold.Comment: 13 pages, no figure
Lax pair tensors and integrable spacetimes
The use of Lax pair tensors as a unifying framework for Killing tensors of
arbitrary rank is discussed. Some properties of the tensorial Lax pair
formulation are stated. A mechanical system with a well-known Lax
representation -- the three-particle open Toda lattice -- is geometrized by a
suitable canonical transformation. In this way the Toda lattice is realized as
the geodesic system of a certain Riemannian geometry. By using different
canonical transformations we obtain two inequivalent geometries which both
represent the original system. Adding a timelike dimension gives
four-dimensional spacetimes which admit two Killing vector fields and are
completely integrable.Comment: 10 pages, LaTe
Heterogeneous Effects of Intensive Glycemic and Blood Pressure on Cardiovascular Events Among Diabetes by Living Arrangements
糖尿病患者における厳格な血糖・血圧管理の効果が、居住形態によって異なることが明らかに. 京都大学プレスリリース. 2024-07-03.Background: Although living alone versus with others is a key social element for cardiovascular prevention in diabetes, evidence is lacking about whether the benefit of intensive glycemic and blood pressure (BP) control differs by living arrangements. We thus aim to investigate heterogeneity in the joint effect of intensive glycemic and BP control on cardiovascular events by living arrangements among participants with diabetes. Methods and results: This study included 4731 participants with diabetes in the ACCORD-BP (Action to Control Cardiovascular Risk in Diabetes-Blood Pressure) trial. They were randomized into 4 study arms, each with glycated hemoglobin target (intensive, <6.0% versus standard, 7.0-7.9%) and systolic BP target (intensive, <120 mm Hg versus standard <140 mm Hg). Cox proportional hazard models were used to estimate the joint effect of intensive glycemic and BP control on the composite cardiovascular outcome according to living arrangements. At a mean follow-up of 4.7 years, the cardiovascular outcome was observed in 445 (9.4%) participants. Among participants living with others, intensive treatment for both glycemia and BP showed decreased risk of cardiovascular events compared with standard treatment (hazard ratio [HR], 0.68 [95% CI, 0.51-0.92]). However, this association was not found among participants living alone (HR, 0.96 [95% CI, 0.58-1.59]). P for interaction between intensive glycemic and BP control was 0.53 among participants living with others and 0.009 among those living alone (P value for 3-way interaction including living arrangements was 0.049). Conclusions: We found benefits of combining intensive glycemic and BP control for cardiovascular outcomes among participants living with others but not among those living alone. Our study highlights the critical role of living arrangements in intensive care among patients with diabetes
Ambulatory dispersal in Tetranychus urticae: an artificial selection experiment on propensity to disperse yields no response
Dispersal to new hosts is an important process for an invasive herbivore, such as the two-spotted spider mite. A recent study, using artificial selection experiments, has suggested that genetic variation and genetic trade-offs are present for propensity to disperse in this species. However, due to the experimental setup alternative explanations for the response to selection could not be ruled out. Using an altered setup, we investigated whether the propensity for ambulatory dispersal differs genetically between individuals and whether genetic correlations with life-history traits exist. Upward and downward selection on propensity to leave the colony was performed for seven generations in four replicate artificial selection experiments and the results were compared to control lines. No consistent responses to selection were found and no significant effect on life-history traits (oviposition rate, juvenile survival, development rate and number of adult offspring) or sex ratio was present across the replicates. The data suggest that our base population of spider mites harbours at best a low amount of additive genetic variation for this behaviour
Towards the conversion of carbohydrate biomass feedstocks to biofuels via hydroxylmethylfurfural
This review appraises the chemical conversion processes recently reported for the production of
hydroxylmethylfurfural (HMF), a key biorefining intermediate, from carbohydrate biomass
feedstocks. Catalytic sites or groups required for the efficient and selective conversion of hexose
substrates to HMF are examined. The principle of concerted catalysis was used to rationalise the
dehydration of fructose and glucose to HMF in non-aqueous media. A survey of reported reaction
routes to diesel-range biofuel intermediates from HMF or furfural is presented and self-condensation
reaction routes for linking two or more HMF and furfural units together toward obtaining kerosene and diesel-range biofuel intermediates are highlighted. The reaction routes include: benzoin condensation, condensation of furfuryl alcohols, hetero Diels–Alder reaction and ketonisation
reaction. These reaction routes are yet to be exploited despite their potential for obtaining kerosene and diesel-range biofuel intermediates exclusively from furfural or hydroxylmethylfurfural
Turbulence in Boundary Flow of Superfluid He Triggered by Free Vortex Rings
The transition to turbulence in the boundary flow of superfluid He is
investigated using a vortex--free vibrating wire. At high wire vibration
velocities, we found that stable alternating flow around the wire enters a
turbulent phase triggered by free vortex rings. Numerical simulations of vortex
dynamics demonstrate that vortex rings can attach to the surface of an
oscillating obstacle and expand unstably due to the boundary flow of the
superfluid, forming turbulence. Experimental investigations indicate that the
turbulent phase continues even after stopping the injection of vortex rings,
which is also confirmed by the simulations.Comment: 4 pages, 4 figures, submitted to AP
High Potential of a Transposon mPing as a Marker System in japonica × japonica Cross in Rice
Although quantitative traits loci (QTL) analysis has been widely performed to isolate agronomically important genes, it has been difficult to obtain molecular markers between individuals with similar phenotypes (assortative mating). Recently, the miniature inverted-repeat transposable element mPing was shown to be active in the japonica strain Gimbozu EG4 where it had accumulated more than 1000 copies. In contrast, most other japonicas, including Nipponbare, have 50 or fewer mPing insertions in their genome. In this study we have exploited the polymorphism of mPing insertion sites to generate 150 PCR markers in a cross between the closely related japonicas, Nipponbare × Gimbozu (EG4). These new markers were distributed in genic regions of the whole genome and showed significantly higher polymorphism (150 of 183) than all other molecular markers tested including short sequence repeat markers (46 of 661). In addition, we performed QTL analysis with these markers using recombinant inbred lines derived from Nipponbare × Gimbozu EG4, and successfully mapped a locus involved in heading date on the short arm of chromosome 6. Moreover, we could easily map two novel loci involved in the culm length on the short arms of chromosomes 3 and 10
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