28,181 research outputs found
BRST quantization of quasi-symplectic manifolds and beyond
We consider a class of \textit{factorizable} Poisson brackets which includes
almost all reasonable Poisson structures. A particular case of the factorizable
brackets are those associated with symplectic Lie algebroids. The BRST theory
is applied to describe the geometry underlying these brackets as well as to
develop a deformation quantization procedure in this particular case. This can
be viewed as an extension of the Fedosov deformation quantization to a wide
class of \textit{irregular} Poisson structures. In a more general case, the
factorizable Poisson brackets are shown to be closely connected with the notion
of -algebroid. A simple description is suggested for the geometry underlying
the factorizable Poisson brackets basing on construction of an odd Poisson
algebra bundle equipped with an abelian connection. It is shown that the
zero-curvature condition for this connection generates all the structure
relations for the -algebroid as well as a generalization of the Yang-Baxter
equation for the symplectic structure.Comment: Journal version, references and comments added, style improve
(In)Consistencies in responses to sodium bicarbonate supplementation: a randomised, repeated measures, counterbalanced and double-blind study
Objectives:
Intervention studies do not account for high within-individual variation potentially compromising the magnitude of an effect. Repeat administration of a treatment allows quantification of individual responses and determination of the consistency of responses. We determined the consistency of metabolic and exercise responses following repeated administration of sodium bicarbonate (SB).
Design and Methods:
15 physically active males (age 25 ± 4 y; body mass 76.0 ± 7.3 kg; height 1.77 ± 0.05 m) completed six cycling capacity tests at 110% of maximum power output (CCT 110% ) following ingestion of either 0.3 g.kg -1 BM of SB (4 trials) or placebo (PL, 2 trials). Blood pH, bicarbonate, base excess and lactate were determined at baseline, pre-exercise, post-exercise and 5-min post-exercise. Total work done (TWD) was recorded as the exercise outcome.
Results:
SB supplementation increased blood pH, bicarbonate and base excess prior to every trial (all p ≤0.001); absolute changes in pH, bicarbonate and base excess from baseline to pre-exercise were similar in all SB trials (all p > 0.05). Blood lactate was elevated following exercise in all trials (p ≤ 0.001), and was higher in some, but not all, SB trials compared to PL. TWD was not significantly improved with SB vs. PL in any trial (SB1: +3.6%; SB2 +0.3%; SB3: +2.1%; SB4: +6.7%; all p > 0.05), although magnitude-based inferences suggested a 93% likely improvement in SB4. Individual analysis showed ten participants improved in at least one SB trial above the normal variation of the test although five improved in none.
Conclusions:
The mechanism for improved exercise with SB was consistently in place prior to exercise, although this only resulted in a likely improvement in one trial. SB does not consistently improve high intensity cycling capacity, with results suggesting that caution should be taken when interpreting the results from single trials as to the efficacy of SB supplementation.
Trial Registration:
ClinicalTrials.gov NCT0247462
Evapotranspiração de um pomar de mangueiras irrigadas na região do Submédio São Franscisco.
O presente trabalho objetivou determinar aevapotranspiração durante o ciclo produtivo da mangueira,variedade ?Tommy Atknis`, cultivada nas condições declima e solo da região do Submédio São Francisco
Avaliacao tecnico-economica do sistema policultivar do feijao macassar (Vigna unguiculata), no Estado do Piaui.
Influência do erro psicrométrico no balanço de energia pela razão de Bowen em um parreiral sob irrigação localizada no Submédio São Francisco.
- …