Energy demands in taekwondo athletes during combat simulation

The purpose of this study was to investigate energy system contributions and energy costs in combat situations. The sample consisted of 10 male taekwondo athletes (age: 21 +/- 6 years old; height: 176.2 +/- 5.3 cm; body mass: 67.2 +/- 8.9 kg) who compete at the national or international level. To estimate the energy contributions, and total energy cost of the fights, athletes performed a simulated competition consisting of three 2 min rounds with a 1 min recovery between each round. The combats were filmed to quantify the actual time spent fighting in each round. The contribution of the aerobic (WAER), anaerobic alactic (W-PCR), and anaerobic lactic (Wleft perpendicularLA-right perpendicular) energy systems was estimated through the measurement of oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the change in blood lactate concentration in each round, respectively. The mean ratio of high intensity actions to moments of low intensity (steps and pauses) was similar to 1:7. The W-AER, W-PCR and (Wleft perpendicularLA-right perpendicular) system contributions were estimated as 120 +/- 22 kJ (66 +/- 6%), 54 +/- 21 kJ (30 +/- 6%), 8.5 kJ (4 +/- 2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the highintensity actions), and of the aerobic system (responsible by the recovery process between high- intensity actions).

Characterization of an extrapolation chamber for low-energy X-rays: Experimental and Monte Carlo preliminary results

The extrapolation chamber is a parallel-plate ionization chamber that allows variation of its air-cavity volume. In this work, an experimental study and MCNP-4C Monte Carlo code simulations of an ionization chamber designed and constructed at the Calibration Laboratory at IFEN to be used as a secondary dosimetry standard for low-energy X-rays are reported. The results obtained were within the international recommendations, and the simulations showed that the components of the extrapolation chamber may influence its response up to 11.0%. (C) 2011 Elsevier Ltd. All rights reserved.

The SUCEST-FUN regulatory network database: Designing an energy grass

Modern sugarcane cultivars are complex hybrids resulting from crosses among several Saccharum species. Traditional breeding methods have been employed extensively in different countries over the past decades to develop varieties with increased sucrose yield and resistance to pests and diseases. Conventional variety improvement, however, may be limited by the narrow pool of suitable genes. Thus, molecular genetics is seen as a promising tool to assist in the process of developing improved varieties. The SUCEST-FUN Project (http://sucest-fun.org) aims to associate function with sugarcane genes using a variety of tools, in particular those that enable the study of the sugarcane transcriptome. An extensive analysis has been conducted to characterise, phenotypically, sugarcane genotypes with regard to their sucrose content, biomass and drought responses. Through the analysis of different cultivars, genes associated with sucrose content, yield, lignin and drought have been identified. Currently, tools are being developed to determine signalling and regulatory networks in grasses, and to sequence the sugarcane genome, as well as to identify sugarcane promoters. This is being implemented through the SUCEST-FUN (http://sucest-fun.org) and GRASSIUS databases (http://grassius.org), the cloning of sugarcane promoters, the identification of cis-regulatory elements (CRE) using Chromatin Immunoprecipitation-sequencing (ChIP-Seq) and the generation of a comprehensive Signal Transduction and Transcription gene catalogue (SUCAST Catalogue).

Influence of pattern gradation on the design of piezocomposite energy harvesting devices using topology optimization

Piezoelectric materials can be used to convert oscillatory mechanical energy into electrical energy. Energy harvesting devices are designed to capture the ambient energy surrounding the electronics and convert it into usable electrical energy. The design of energy harvesting devices is not obvious, requiring optimization procedures. This paper investigates the influence of pattern gradation using topology optimization on the design of piezocomposite energy harvesting devices based on bending behavior. The objective function consists of maximizing the electric power generated in a load resistor. A projection scheme is employed to compute the element densities from design variables and control the length scale of the material density. Examples of two-dimensional piezocomposite energy harvesting devices are presented and discussed using the proposed method. The numerical results illustrate that pattern gradation constraints help to increase the electric power generated in a load resistor and guides the problem toward a more stable solution. (C) 2012 Elsevier Ltd. All rights reserved.

CdSe/CdTe interface band gaps and band offsets calculated using spin-orbit and self-energy corrections

We performed ab initio calculations of the electronic structures of bulk CdSe and CdTe, and their interface band alignments on the CdSe in-plane lattice parameters. For this, we employed the LDA-1/2 self-energy correction scheme [L.G. Ferreira, M. Marques, L.K. Teles, Phys. Rev. B 78 (2008) 125116] to obtain corrected band gaps and band offsets. Our calculations include the spin-orbit effects for the bulk cases, which have shown to be of importance for the equilibrium systems and are possibly degraded in these strained semiconductors. Therefore, the SO showed reduced importance for the band alignment of this particular system. Moreover, the electronic structure calculated along the transition region across the CdSe/CdTe interface shows an interesting non-monotonic variation of the band gap in the range 0.8-1.8 eV, which may enhance the absorption of light for corresponding frequencies at the interface between these two materials in photovoltaic applications. (C) 2012 Elsevier B.V. All rights reserved.

Oxygen reduction reaction on a Pt/carbon fuel cell catalyst in the presence of trace quantities of ammonium ions: An RRDE study

The effect of trace quantities of ammonia on oxygen reduction reaction (ORR) on carbon-supported platinum catalysts in perchloric acid solutions is assessed using rotating ring disk electrode (RRDE) technique. The study demonstrates that ammonia has detrimental effects on ORR. The most significant effect takes place in the potential region above 0.7 V vs RHE. The effect is explained by the electrochemical oxidation of ammonia, which blocks Pt active sites and increases the formation of H2O2. This leads to losses in the disk currents and increments in the ring currents. The apparent losses in ORR currents may occur in two ways, namely, through the blocking of the active sites for ORR as well as by generating a small anodic current, which is believed to have a lower contribution. In addition, a detrimental effect of sodium cations in the potential range below 0.75 V vs RHE was demonstrated. This effect is most likely due to the co-adsorption of sodium cations and perchlorate anions on the Pt surface. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Effects of high-energy astrophysical events on habitable planets

With the possible exception of meteor impacts, high-energy astrophysical events such as supernovae, gamma-ray bursts (GRB) and flares are usually not taken into account for biological and evolutionary studies due to their low rates of occurrence. We show that a class of these events may occur at distances and time scales in which their biological effects are non-negligible, maybe more frequent than the impacts of large asteroids. We review the effects of four transient astrophysical sources of ionizing radiation on biospheres - stellar flares, giant flares from soft gamma repeaters (SGR), supernovae and GRB. The main damaging features of them are briefly discussed and illustrated. We point out some open problems and ongoing work. Received 28 February 2012, accepted 6 July 2012, first published online 10 August 2012

SEARCH FOR POINT-LIKE SOURCES OF ULTRA-HIGH ENERGY NEUTRINOS AT THE PIERRE AUGER OBSERVATORY AND IMPROVED LIMIT ON THE DIFFUSE FLUX OF TAU NEUTRINOS

The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E-nu between 10(17) eV and 10(20) eV from point-like sources across the sky south of +55 degrees and north of -65 degrees declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of similar to 3.5 years of a full surface detector array for the Earth-skimming channel and similar to 2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k(PS) . E-nu(-2). from a point-like source, 90% confidence level upper limits for k(PS) at the level of approximate to 5x10(-7) and 2.5x10(-6) GeV cm(-2) s(-1) have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos, respectively.

Density Functional Theory (DFT) Study of Edaravone Derivatives as Antioxidants

Quantum chemical calculations at the B3LYP/6-31G* level of theory were employed for the structure-activity relationship and prediction of the antioxidant activity of edaravone and structurally related derivatives using energy (E), ionization potential (IP), bond dissociation energy (BDE), and stabilization energies(Delta E-iso). Spin density calculations were also performed for the proposed antioxidant activity mechanism. The electron abstraction is related to electron-donating groups (EDG) at position 3, decreasing the IP when compared to substitution at position 4. The hydrogen abstraction is related to electron-withdrawing groups (EDG) at position 4, decreasing the BDECH when compared to other substitutions, resulting in a better antioxidant activity. The unpaired electron formed by the hydrogen abstraction from the C-H group of the pyrazole ring is localized at 2, 4, and 6 positions. The highest scavenging activity prediction is related to the lowest contribution at the carbon atom. The likely mechanism is related to hydrogen transfer. It was found that antioxidant activity depends on the presence of EDG at the C-2 and C-4 positions and there is a correlation between IP and BDE. Our results identified three different classes of new derivatives more potent than edaravone.

Mapping the Energy Distribution of SERRS Hot Spots from Anti-Stokes to Stokes Intensity Ratios

The anomalies in the anti-Stokes to Stokes intensity ratios in single-molecule surface-enhanced resonance Raman scattering were investigated. Brilliant green and crystal violet dyes were the molecular probes, and the experiments were carried out on an electrochemically activated Ag surface. The results allowed new insights into the origin of these anomalies and led to a new method to confirm the single-molecule regime in surface-enhanced Raman scattering. Moreover, a methodology to estimate the distribution of resonance energies that contributed to the imbalance in the anti-Stokes to Stokes intensity ratios at the electromagnetic hot spots was proposed. This method allowed the local plasmonic resonance energies on the metallic surface to be spatially mapped.

From inflation to dark energy through a dynamical Λ: an attempt at alleviating fundamental cosmic puzzles

After decades of successful hot big-bang paradigm, cosmology still lacks a framework in which the early inflationary phase of the universe smoothly matches the radiation epoch and evolves to the present “quasi” de Sitter spacetime. No less intriguing is that the current value of the effective vacuum energy density is vastly smaller than the value that triggered inflation. In this paper, we propose a new class of cosmologies capable of overcoming, or highly alleviating, some of these acute cosmic puzzles. Powered by a decaying vacuum energy density, the spacetime emerges from a pure nonsingular de Sitter vacuum stage, “gracefully” exits from inflation to a radiation phase followed by dark matter and vacuum regimes, and, finally, evolves to a late-time de Sitter phase.