Fast Monte Carlo simulations and singularities in the probability distributions of non-equilibrium systems

A numerical technique is introduced that reduces exponentially the time required for Monte Carlo simulations of non-equilibrium systems. Results for the quasi-stationary probability distribution in two model systems are compared with the asymptotically exact theory in the limit of extremely small noise intensity. Singularities of the non-equilibrium distributions are revealed by the simulations.Comment: 4 pages, 4 figure

Novel integrated tunable laser using filtered feedback for simple and very fast tuning

We present a novel integrated tunable laser based on filtered feedback, which combines a simple tuning method with ns switching speed

Fast integrated tunable laser using filtered feedback

A novel integrated tunable laser is presented which combines a simple tuning method with ns switching speed. The Photonic Integrated Circuit consists of a Fabry-Perot laser with deeply-etched DBR mirrors. The Fabry-Perot modes can be selected independently using an Arrayed Waveguide Grating and then re-injected into the laser cavity, forcing single mode operation at the wavelength of that mode. 4ns switching time as well as 15 dB SMSR is demonstrated on the prototype device

Integrated filtered-feedback tunable laser with enhanced control of feedback phase

Recently we presented a novel discretely tunable laser that consists of a Fabry-Perot laser which was forced to operate in single-mode condition by applying on-chip filtered feedback. The laser switches extremely fast (3 ns) and requires simple on/off control currents to switch the wavelength. In these first devices it was not possible to control the phase of the feedback light independently from the feedback intensity. In was solved by adding an extra electrode allowing us to control the phase separately. In this paper we present the new device and study the effect of the control ofthefeedbackphase in order to improve the performance ofthe original tunable laser concept

Composting Rice Straw in Semi-Arid Conditions

Five experiments were conducted, three with 10-kg lots (in cement cylinders/digesters) and two in heaps with 500-kg lots of rice straw. Results from three—one with cement cylinders and two with heaps—are reported here. All were conducted at Patancheru from 1998 to 2000 in the hot summer period (April–May). The use of 0.76% N (as urea) with or without added micro-organisms more quickly decomposed the rice straw (by a subjective visual rating scale and C:N ratio) by about 1 week than otherwise. Also, the compost of N-applied treatments had at least 40% more N than that from the non-applied control. But N loss, indicated by the odour of ammonia, was noticed only from the N-applied treatments. All the treatments, except the control, received 25% rock phosphate (RP), when composting was done in cement digesters. For heap composting, RP was reduced to 6% so that its concentration would not be excessive when the compost is applied to crops at high rates. Composting was accomplished within 45 days whether in the digesters or in heaps, even with a reduced use of N (0.36% in 1999 and 0.1% in the year 2000). Treatment effects due to N that were apparent in the final product, disappeared when N-application was reduced to 0.3% or 0.1%. It was only through the visual rating that amendment with N and micro-organisms was perceived to shorting composting time. The resultant compost, however, did not indicate differences in chemical characteristics (N, P, K, OC%) across treatments in heap composting. One apparent biological difference across treatments was the presence of fruiting bodies of Sclerotium rolfsii (causes root rots in many crops) in control treatments. This fungus was not seen in treatments receiving microbial inoculation. In the experiment in 1999, we composted over 6 t of rice straw in a single session, in multiple heaps of 500 kg. The composting protocol is proposed for a small-scale village-level enterprise and is not intended for individual farmer

Quasinormal modes of a Schwarzschild black hole surrounded by free static spherically symmetric quintessence: Electromagnetic perturbations

In this paper, we evaluated the quasinormal modes of electromagnetic perturbation in a Schwarzschild black hole surrounded by the static spherically symmetric quintessence by using the third-order WKB approximation when the quintessential state parameter $w_{q}$ in the range of $-1/3<w_{q}<0$. Due to the presence of quintessence, Maxwell field damps more slowly. And when at $-1<w_{q}<-1/3$, it is similar to the black hole solution in the ds/Ads spacetime. The appropriate boundary conditions need to be modified.Comment: 6 pages, 3 figure

A new index to assess soil quality and sustainability of wheat-based cropping systems

Sustainability index was calculated to assess soil quality under the influence of different fertilizer management practices. It is based on the area of the triangle in which nutrient index, microbial index and crop index of soil represented the three vertices of a triangle. Nutrient index reflected the nutrient status of soil and was calculated from the measurements of various soil chemical parameters. Microbial index was calculated by determining various soil microbial and biochemical activities and crop index by measuring of crop yield parameters. Eighteen soil indicators were determined to assess nutrient index, microbial index and crop index in order to compare the effect of different sources of nutrients such as green manure, farmyard manure and chemical fertilizer in a rice/corn-wheat rotation. The indices were applied to assess the sustainability of five field experiments with respect to the different fertilizer treatments. The long-term application of organic manures in rice/corn-wheat cropping system increased the index value because it increased the nutrient index, microbial index and crop index of soils. The use of only chemical fertilizers in the rice-wheat cropping system resulted in poor soil microbial index and crop index. In corn-wheat system, additional application of FYM at 10 t ha-1 before sowing corn made the system more sustainable than application of 100% NPK; the sustainability index values were 2.43 (the highest for this system) and 0.93, respectivel

Preparation and evaluation of Rice-Straw Compost

Rice-straw is an important cattle field in several asian countries even though its quality is low. But in some areas of at least five countries it is burnt. A procedure for rapid composting of rice straw in lots of 10 kg straw in the semi-arid tropics was standardised using Aspergillus awamori, Pseudomonas stritata and bacillus polymyxa..........

Flat bands in topological media

Topological media are systems whose properties are protected by topology and thus are robust to deformations of the system. In topological insulators and superconductors the bulk-surface and bulk-vortex correspondence gives rise to the gapless Weyl, Dirac or Majorana fermions on the surface of the system and inside vortex cores. Here we show that in gapless topological media, the bulk-surface and bulk-vortex correspondence is more effective: it produces topologically protected gapless fermions without dispersion -- the flat band. Fermion zero modes forming the flat band are localized on the surface of topological media with protected nodal lines and in the vortex core in systems with topologically protected Fermi points (Weyl points). Flat band has an extremely singular density of states, and we show that this property may give rise in particular to surface superconductivity which could exist even at room temperature.Comment: 9 pages, 5 figures, version to appear in JETP Letter