Effects of light and soil flooding on the growth and photosynthesis of ramin (Gonystylus bancanus) seedlings in Malaysia

We studied the ecophysiology of ramin (Gonystylus bancanus) seedlings in an experimental set up at the Forest Research Centre in Kuching, Sarawak, Malaysia. Ramin seedlings were grown on flooded and drained peat soil under 100, 76, 46 and 23% sunlight, thus simulating effects of different light conditions (canopy gap size) and drainage that occur in natural ramin populations. Seedling growth was highest in partial sunlight (76%) and reduced with reducing light levels. Aboveground productivity and fine root development were significantly higher in seedlings grown on flooded soil compared with those on drained soil. In contrast, investment in coarse root biomass was significantly higher in seedlings grown on drained soil. It appeared that the aboveground growth benefits in flooded conditions were the result of more advantageous conditions for allocation of carbon to leaves, thus enhancing overall relative growth rates through higher light interception rates despite lower photosynthetic capacity. The results of this experiment suggested that drainage of peat swamp forests would seriously hamper natural regeneration of ramin by limiting the growth of seedlings. It is also suggested that selective logging operations which produce medium-size canopy gaps improve ramin regeneration in hydrologically undisturbed mixed swamp forest

Why do high jumpers use a curved approach?

Currently all elite high jumpers use the Fosbury Flop technique with a curved approach. This suggests that the curved approach presents some clear advantage although there is no general agreement upon the mechanism or the mechanics. This study aimed to determine the characteristics of the approach curve and to investigate how it contributes to the generation of somersault rotation. A simple theoretical model was used to demonstrate that a tightening approach curve would change the inward lean towards the centre of the curve into outwards lean. Three-dimensional video analysis was conducted on performances of two elite male high jumpers in competition. It was found that in each case the radius of the approach curve and the inward lean angle both decreased towards the end of the approach (p < 0.01). The amount of outward lean angular velocity generated was shown to be a major proportion of the required somersault angular velocity for a jump. It was concluded that the main advantage of a curved approach was that it resulted in the generation of somersault velocity providing the curve tightened towards the end of the approach

Structural and electrical properties of Nb-substituted LiTa1-xNbxO3

Single phase LiTa1-xNbxO3 solid solution with 0.00 ≤ x ≤ 1.00 was successfully synthesised via conventional solid-state method at 950°C for 24 h. These materials were refined and fully indexed with hexagonal crystal system, space group of R3c; lattice parameters, a ranging from 5.1410(6) Ǻ to 5.1471(3) Ǻ and c ranging from 13.7467(1) Ǻ to 13.8341(1) Ǻ; with α = β = 90° and γ = 120°. Variation of the lattice parameters in these materials was found to be negligibly small throughout the subsolidus solution. No thermal event was detected within the studied temperature range of 50 to 1000°C. The electrical properties of samples were characterised by AC impedance analyser, HP4192A at temperature ranging from room temperature to 850°C over a frequency range of 5 Hz to 13 MHz. LiTa1-xNbxO3 materials exhibited bulk response with associated capacitances in the order of 10-12 F cm-1 and the temperature-dependent conductivities were found to increase with increasing temperatures. The results showed that LiTa1-xNbxO3 samples were of typical ferroelectrics

Influence of Nb2O5 substitution on the structural and electrical properties of Bi3TaO7 ceramics

Herein we report the doping mechanism and impedance study of the Nb-substituted Bi3Ta1-xNbxO7 (0 ≤ x ≤ 0.5) prepared via conventional solid-state method at 900 °C over 24 h. The substitutional solid solution crystallised in a cubic fluorite structure, space group Fm-3m and with lattice parameter, a = b = c, in the range 5.4477 (±0.0037)–5.4654 (±0.0011) Å. An insignificant unit cell expansion was observed with increasing Nb2O5 content and the linear correlation between lattice parameter and composition variable showed that the Vegard's Law was obeyed. Both TGA and DTA analyses confirmed that the Bi3Ta1-xNbxO7 solid solution was thermally stable as neither phase transition nor weight loss was observed within the studied temperature range, ∼28 °C–1000 °C. The electrical conductivities of these samples were found to increase with increasing Nb concentration; the Bi3Ta0.5Nb0.5O7 exhibited the highest conductivity, ∼1.2 × 10−2 S cm−1 at 700 °C with a low activation energy of 1.03 eV

Phase formation and dielectric properties of pentavalent cation doped non-stoichiometric Bismuth Zinc Niobate (BZN) cubic pyrochlore.

In an attempt to synthesize new solid solutions and search for better performance materials, pentavalent cation dopants were introduced into the non stoichiometric BZN cubic pyrochlore, Bi3Zn1.84Nb3O13.84. Extensive solid solutions were formed in Bi3Zn1.84Nb3-xDxO13.84 with limit at x = 3 and 2.6 for D = Ta and Sb, respectively. This illustrates the possibility of cationexchange solid solutions due to similarity in dopants’ ionic radii. The elemental analysis confirmed the stoichiometry of doped materials with no deleterious Bi2O3 loss. Ta / Sb doped samples were highly resistive with activation energies ranging from 1.2 - 1.9 eV. Temperature coefficient of capacitance, TCC, decreased from -396 ppm / oC to ~ -180 ppm / oC and ~ -90 ppm / oC for both end members, respectively

Quantum Cryptography Using Single Particle Entanglement

A quantum cryptography scheme based on entanglement between a single particle state and a vacuum state is proposed. The scheme utilizes linear optics devices to detect the superposition of the vacuum and single particle states. Existence of an eavesdropper can be detected by using a variant of Bell's inequality.Comment: 4 pages, 3figures, revte

Associations of Leisure-Time Physical Activity and Television Viewing With Life Expectancy Free of Nonfatal Cardiovascular Disease: The ARIC Study

Background High levels of physical activity have been associated with longer life expectancy free of cardiovascular disease (CVD), but specific types of CVD and sedentary behavior have not been examined. We examined associations of leisure-time moderate-to-vigorous physical activity (LTPA) and television viewing with life expectancy free of 3 types of CVD. Methods and Results We included 13 534 participants from the ARIC (Atherosclerosis Risk in Communities) cohort. We used multistate survival models to estimate associations of LTPA in the past year (no LTPA, less than the median, equal to or greater than the median) and television viewing (often or very often, sometimes, seldom or rarely) with life expectancy at age 50 free of nonfatal coronary heart disease (CHD), stroke, and heart failure (HF). Over 27 years of follow-up, 4519 participants developed one of the 3 nonfatal CVDs and 5475 deaths occurred. Compared with participants who engaged in no LTPA, participants who engaged in LTPA equal to or greater than the median had longer life expectancy free of nonfatal CHD (men: 1.5 years [95% CI, 1.0-2.0]; women: 1.6 years [95% CI, 1.1-2.2]), stroke (men: 1.8 years [95% CI, 1.2-2.3]; women: 1.8 years [95% CI, 1.3-2.3]), and HF (men: 1.6 years [95% CI, 1.1-2.1]; women: 1.7 years [95% CI, 1.2-2.2]). Compared with viewing more television, watching less television was associated with longer life expectancy free of CHD, stroke, and HF (≈0.8 year). Conclusions Higher levels of LTPA and less television viewing were associated with longer life expectancy free of CHD, stroke, and HF. Engaging in LTPA and watching less television may increase the number of years lived free of CHD, stroke, and HF