99 research outputs found
A continuum description of the energetics and evolution of stepped surfaces in strained nanostructures
As a departure from existing continuum approaches for describing the
stability and evolution of surfaces of crystalline materials, this article
provides a description of surface evolution based on the physics of the main
feature imposed by the discrete nature of the material, namely,
crystallographic surface steps. It is shown that the formation energy of
surface steps depends on the sign of extensional strain of the crystal surface,
and this behavior plays a crucial role in surface evolution. The nature of this
dependence implies that there is no energetic barrier to nucleation of islands
on the growth surface during deposition, and that island faces tend toward
natural orientations which have no counterpart in unstrained materials. This
behavior is expressed in terms of a small number of parameters that can be
estimated through atomistic analysis of stepped surfaces. The continuum
framework developed is then applied to study the time evolution of surface
shape of an epitaxial film being deposited onto a substrate. The kinetic
equation for mass transport is enforced in a weak form by means of a
variational formulation [...].Comment: 25 pages, 7 figs, KEYWORDS=surface diffusion, surface energy,
morphology evolution, semiconductor material, stability and bifurcatio
Cardiovascular autonomic modulation differences between moderate-intensity continuous and high-intensity interval aerobic training in women with PCOS: A randomized trial
Background: Moderate-intensity continuous training (MICT) is strongly recommended for polycystic ovarian syndrome (PCOS) treatment. However, recent studies have suggested that high-intensity interval training (HIIT) would promote great benefits for cardiac autonomic control. Therefore, we investigated whether the benefits of HIIT related to cardiovascular autonomic control were greater than those of MICT in women with PCOS.
Methods: Women with PCOS were randomly allocated through a blind draw into three groups: control, MICT, and HIIT. The control group did not undergo exercise, whereas those in the MICT and HIIT groups underwent 16 weeks of aerobic physical training. All groups were evaluated before and after the 16 weeks of intervention in the following aspects: quantification of serum lipids, testosterone, fasting insulin and blood glucose; physical fitness through cardiopulmonary testing; analysis of heart rate variability (HRV) by linear (time domain and frequency domain) and non-linear (symbolic analysis) methods, analysis of blood pressure variability (BPV) and spontaneous baroreflex sensitivity (BRS).
Results: The final analysis, each group comprised 25 individuals. All groups had similar baseline parameters. After 16 weeks, intragroup comparison showed that the MICT and HIIT groups had a reduction in baseline heart rate (P < 0.001; P < 0.001, respectively) and testosterone levels P < 0.037; P < 0.012, respectively) associated with an increase in VO2peak (MICT, P < 0.001; HIIT, P < 0.001). The MICT (P < 0.36) and HIIT (P < 0.17) groups also showed an increase in cardiac vagal modulation, however only observed in the non-linear analysis. The intergroup comparison showed no differences between the MICT and HIIT groups in any of the hormonal, metabolic and autonomic parameters evaluated, including testosterone, peak oxygen uptake (VO2peak), HRV, BPV and BRS.
Conclusion: HIIT and MICT showed similar results for the different parameters evaluated. This suggests that both training protocols can be recommended for the treatment of PCOS. Brazilian Clinical Trials Registry (RBR-78qtwy)
Soliton back-action evading measurement using spectral filtering
We report on a back-action evading (BAE) measurement of the photon number of
fiber optical solitons operating in the quantum regime. We employ a novel
detection scheme based on spectral filtering of colliding optical solitons. The
measurements of the BAE criteria demonstrate significant quantum state
preparation and transfer of the input signal to the signal and probe outputs
exiting the apparatus, displaying the quantum-nondemolition (QND) behavior of
the experiment.Comment: 5 pages, 5 figure
Tétano em pequenos ruminantes: estudo retrospectivo dos principais achados clínico-epidemiológicos em 11 casos
Efeito do peso ao abate nos rendimentos dos processamentos do pacu (Piaractus mesopotamicus)
Analysis of floristic composition and structure as an aid to monitoring protected areas of dense rain forest in southeastern Brazil
Pré-tratamento com ácido sulfúrico na germinação de sementes de Ziziphus joazeiro Mart.: Rhamnaceae
Intralesional polysulphated glycosaminoglycan as treatment of equine collagenase induced tendinitis: clinical, ultrasonographic and histopathologic evaluation
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