Planetesimal formation by the streaming instability in a photoevaporating disk

Recent years have seen growing interest in the streaming instability as a candidate mechanism to produce planetesimals. However, these investigations have been limited to small-scale simulations. We now present the results of a global protoplanetary disk evolution model that incorporates planetesimal formation by the streaming instability, along with viscous accretion, photoevaporation by EUV, FUV, and X-ray photons, dust evolution, the water ice line, and stratified turbulence. Our simulations produce massive (60-130 $M_\oplus$) planetesimal belts beyond 100 au and up to $\sim 20 M_\oplus$ of planetesimals in the middle regions (3-100 au). Our most comprehensive model forms 8 $M_\oplus$ of planetesimals inside 3 au, where they can give rise to terrestrial planets. The planetesimal mass formed in the inner disk depends critically on the timing of the formation of an inner cavity in the disk by high-energy photons. Our results show that the combination of photoevaporation and the streaming instability are efficient at converting the solid component of protoplanetary disks into planetesimals. Our model, however, does not form enough early planetesimals in the inner and middle regions of the disk to give rise to giant planets and super-Earths with gaseous envelopes. Additional processes such as particle pileups and mass loss driven by MHD winds may be needed to drive the formation of early planetesimal generations in the planet forming regions of protoplanetary disks.Comment: 20 pages, 12 figures; accepted to Ap

Nutrient Management for Higher Productivity of Swarna Sub1 Under Flash Floods Areas

Two field experiments were conducted at Regional Agricultural Research Station, Tarahara, Nepal during 2012 and 2013 to determine the effect of agronomic management on growth and yield of Swarna Sub1 under flash floods. The first experiment was laid out in a split plot design with three replications; and four different nutrient combinations at nursery as main plots and three age groups of rice seedlings as sub plots. The second experiment was laid out in a randomized complete block design and replicated thrice; with three post flood nutrient doses at six and 12 days after de-submergence (dad). The experiments were complete submerged at 10 days after transplanting for 12 days. The survival percentage, at 21 dad, was significantly higher in plots planted with 35 (90.25%) and 40 (91.58%) days-old seedlings compared to 30 days-old seedlings (81.75%). Plots with 35 days-old seedlings produced 5.15 t ha-1 with advantage of 18.83% over 30 days-old seedlings. Plots with 100-50-50 kg N-P2O5-K2O/ha at nursery recorded the highest grain filling of 79.41% and grain yield of 5.068 t/ha with more benefit. Post flood application of 20-20 N-K20kg/ha at 6 dad resulted in higher plant survival and taller plants, leading to significantly higher grain yield of 5.183 t/ha and straw yield of 5.315 t/ha. Hence, 35-40 days old seedlings raised with 100-50-50 kg N-P2O5-K2O /ha in nursery and the additional application of20-20 kg N-K2O /ha at 6 dad improved plant survival and enhanced yield of Swarna Sub1 under flash flood conditions. The practice has prospects of saving crop loss with getting rice yield above national average yield leading to enhanced food security in the flood prone areas of Nepal

Invitro Antimicrobial Activity and Phytochemical Analysis of Ficus religiosa L. and Ficus bengalensis L. against Diarrhoeal Enterotoxigenic E. coli

The barks of Ficus religiosa L. and Ficus bengalensis L., which belongs to family Moraceae, were investigated for invitro antibacterial activity and phytochemical analysis. The various solvents extract like aqueous, methanol, chloroform, petroleum ether and hexane were screened for antibacterial activity against Enterotoxigenic E. coli isolated from diarrhoeal patients. The preliminary phytochemical analysis of the methanol extracts of both the plants showed the presence of carbohydrates, flavonoids, aminoacids, steroids, saponins and tannins. The extracts were subjected for antibacterial activity against Enterotoxignic E.coli (ETEC) at 200mg/ml concentration by disc diffusion method. The results of antibacterial activity revealed that methanol extracts of both the plants barks exhibits good activity compared to chloroform and aqueous extracts. Petroleum ether and hexane extracts did not show any activity. The antibacterial activities of extracts were compared with standard antibiotics

Anthelmintic Activity of Trikatu Churna and its Ingredients

The alcoholic extract of Trikatu churna and its ingredients were evaluated for anthelmintic activity. The dried fruits of Piper nigrum L. (Piperaceae), Piper longum L. (Piperaceae) and rhizome of Zingiber officinale Roscoe. (Zingiberaceae) were powdered and mixed together in equiproportions to get a polyherbal formulation, Trikatu churna. All these three ingredients are spicy, commonly used in our daily diet, also well known for their tremendous therapeutic potential, since from the Vedic period. The alcoholic extract of Trikatu churna and its ingredients were screened for preliminary phytochemical studies and also tested for anthelmintic activity against Pheritima posthuma and recorded the time taken for induction of paralysis and death. Piperazine citrate (10 mg/ml) was included as standard reference and distilled water as control. The results demonstrated that, the extracts of Trikatu churna and its plant ingredients showed the presence of alkaloids, flavonoids, tannins, lignins and steroids, these test samples were also exhibited potent anthelmintic activity, but the highest activity was noticed in Trikatu churna, this might be due to the multifunctional effect of all the three plant ingredients of Trikatu churna. Based on the above results, it is confirmed that, combination of Piper nigrum, Piper longum and Zingiber officinale in Trikatu churna offered promising anthelmintic effect than using the ingredients alone

Physico-chemical parameters for Micro algal culture

Marine microalgae are unicellular in nature, which are the primary producers of the sea. Among microalgae, green algae, flagellate and diatom species, are the primary producers at the base of the marine food chain. It’s an important source of nutrition and is used widely in the aquaculture of other aquatic organisms like finfish and shellfish, etc., either directly or as an added source of basic nutrients. They are cultured in hatcheries for larval rearing of molluscs, crustaceans and fish as a source of nutrition. In hatchery systems, micro algae is also added to the larval rearing tanks to improve ‘quality’ of water. The production of micro algae is very critical in successful hatchery management. Suitably treated seawater enriched with nutrients, like nitrates, phosphates, essential trace elements, vitamins and carbon dioxide is a prerequisite for any successful algal culture. High micro algal biomass with low bacteria content is important to support the growth of finfish or shellfish larvae. In this context Physio-chemical parameters and its management in algal culture systems plays a vital role in enhancing the survival, growth and production of cultivable animals

Quenching Dynamics of a quantum XY spin-1/2 chain in presence of a transverse field

We study the quantum dynamics of a one-dimensional spin-1/2 anisotropic XY model in a transverse field when the transverse field or the anisotropic interaction is quenched at a slow but uniform rate. The two quenching schemes are called transverse and anisotropic quenching respectively. Our emphasis in this paper is on the anisotropic quenching scheme and we compare the results with those of the other scheme. In the process of anisotropic quenching, the system crosses all the quantum critical lines of the phase diagram where the relaxation time diverges. The evolution is non-adiabatic in the time interval when the parameters are close to their critical values, and is adiabatic otherwise. The density of defects produced due to non-adiabatic transitions is calculated by mapping the many-particle system to an equivalent Landau-Zener problem and is generally found to vary as $1/\sqrt{\tau}$, where $\tau$ is the characteristic time scale of quenching, a scenario that supports the Kibble-Zurek mechanism. Interestingly, in the case of anisotropic quenching, there exists an additional non-adiabatic transition, in comparison to the transverse quenching case, with the corresponding probability peaking at an incommensurate value of the wave vector. In the special case in which the system passes through a multi-critical point, the defect density is found to vary as $1/\tau^{1/6}$. The von Neumann entropy of the final state is shown to maximize at a quenching rate around which the ordering of the final state changes from antiferromagnetic to ferromagnetic.Comment: 8 pages, 6 figure

Qualitative and quantitative analysis of antibody response in childhood tuberculosis against antigens of Mycobacterium tuberculosis

Purpose: Serodiagnosis of tuberculosis in children, using available crude antigens, has been difficult. The tests lack sufficient sensitivity and/or specificity. In this study, western blot analysis of M. tuberculosis H37Rv culture filtrate antigen (CFA) was carried out, to identify diagnostically useful antigens. In addition, the CFA was also used in enzyme linked immunosorbent assay (ELISA), to measure antibodies of multiple isotypes. Methods: Specific IgG, IgA and IgM antibodies were estimated in the sera from 26 clinically/ bacteriologically diagnosed cases of childhood tuberculosis (CTB) and 61 normal children (CNHS), using culture filtrate antigen. Western blot analysis with culture filtrate antigen was carried out to qualitatively compare the antibody profile among the CTB, with childhood normal controls and adult TB. Results: IgG positivity was only 7.6% with culture filtrate antigen in the CTB group, while 3.2% among the controls were also positive. However, the results of IgA and IgM isotypes were better. By combination of all the three isotypes an increased sensitivity of 57.7% with a specificity of 93.5%, was obtained. Immunoblot analysis revealed marked difference among antibodies in the region of 16, 19, 38 and 45kDa between CTB and CNHS. Conclusions: Our findings point to a limited sensitivity of 57.7% in ELISA with culture filtrate antigen. However, antibodies around 16, 19,38 and 45kDa region may be useful in differentiating the CTB patients from CNHS by immunoblot assay

Defect production due to quenching through a multicritical point

We study the generation of defects when a quantum spin system is quenched through a multicritical point by changing a parameter of the Hamiltonian as $t/\tau$, where $\tau$ is the characteristic time scale of quenching. We argue that when a quantum system is quenched across a multicritical point, the density of defects ($n$) in the final state is not necessarily given by the Kibble-Zurek scaling form $n \sim 1/\tau^{d \nu/(z \nu +1)}$, where $d$ is the spatial dimension, and $\nu$ and $z$ are respectively the correlation length and dynamical exponent associated with the quantum critical point. We propose a generalized scaling form of the defect density given by $n \sim 1/\tau^{d/(2z_2)}$, where the exponent $z_2$ determines the behavior of the off-diagonal term of the $2 \times 2$ Landau-Zener matrix at the multicritical point. This scaling is valid not only at a multicritical point but also at an ordinary critical point.Comment: 4 pages, 2 figures, updated references and added one figur