Study of young stellar objects and associated filamentary structures in the inner Galaxy

Young Stellar Objects (YSOs) in the inner Galactic region $10^0 < l < 15^0$ and $-1^0 < b < 1^0$ are studied using GLIMPSE images and GLIMPSE data catalogue. A total number of 1107 Class I and 1566 Class II sources are identified in this Galactic region. With the help of GLIMPSE 5.8 $\mu$m & 8 $\mu$m images, we have identified the presence of 10 major star forming sites in the Galactic midplane, of which 8 of them are filamentary while 2 are possible clusters of Class I & II sources. The length of the identified filaments are estimated as 8'-33' ($\sim$ 9 - 56 pc). Occurrence of Hub-Filamentary System (HFS) is observed in many filamentary star forming sites. Most of the Class I sources are found to be aligned along the length of these filamentary structures, while Class II sources have a random distribution. Mass and age distribution of 425 Class I and 241 Class II sources associated with filaments & clusters are studied through their SED analysis. Most of the Class I sources detected have mass $>$ 8M$_\odot$, while Class II sources have relatively low mass regime. Class I sources have ages $\le$ 0.5 Myr, while Class II sources have ages in the range $\sim$0.1 - 3 Myr. Along with the help of high mass star forming tracers, we demonstrate that the 10 regions studied here are forming a large number of high-mass stars.Comment: 19 pages, 18 figures. Accepted for publication in MNRA

ACUTE TOXICITY STUDY AND THERAPEUTIC ACTIVITY OF MODIFIED ARJUNARISHTA ON ISOPROTERENOL-INDUCED MYOCARDIAL INFARCTION IN RATS

Objective: Ayurvedic formulation derived phytomedicine could bring a specific remedy against myocardial infarction (MI) without any side effects. Arjunarishta is a cardio tonic that nourishes and strengthens the myocardial muscle and promotes cardiac function. The preparation of Arjunarishta is modified and it does not involve fermentation. So it is alcohol-free and safe to all age groups. The study of acute toxicity and therapeutic activity of Modified Arjunarishta (MA) in isoproterenol (IPN) induced MI in rats was conducted to bring scientific evidence. Methods: Acute toxicity study: Mice are divided into three groups. Group I-control group; Group II and group III were test groups and they received an oral dose of 1000 mg/kg and 2000 mg/kg of MA, respectively. The experimental mice were observed for behaviour changes and clinical signs. Their body weight was also recorded. At the end of the experiment, blood sample was collected and glucose, liver function test (LFT), renal function test (RFT) and haematology parameters were analysed. Then they also subjected to gross pathological examination of all the major internal organs. Therapeutic study: Rats were divided into six groups. Group 1-normal control; Group 2 (induced)-IPN 85 mg/kg for the first two days; Group 3 (MA low dose)-received IPN as per group 2 followed by MA 200 mg/kg from the 3rd day to the end of the experiment; Group 4 (MA medium dose)-400 mg/kg; Group 5 (MA high dose)-600 mg/kg; Group 6 (Standard)-IPN as per group 2 followed by Arjunarishta 2 ml/kg body weight from the 3rd day to the end of the experiment. The collected serum sample was used for the estimation of myocardium-expressed proinflammatory cytokines. Heart tissue was homogenized for the estimation of calcium and lipid profile. Results: Acute toxicity: There were no signs of toxicity and no significant change in body weight. The value of glucose, RFT, LFT and haematological parameters are remained normal. Histopathological report showed normal architecture. Therapeutic activity: In the heart samples, significantly (p&lt;0.001) increased cholesterol, Triglyceride (TGL), Free Fatty acids (FFA) and calcium in IPN induced groups was noted. They are all significantly (p&lt;0.001) decreased in MA administrated groups of three different groups. In serum sample, a significantly (p&lt;0.001) increased cytokines of Tumor necrosis factor α (TNFα), Interlukins (IL-6, IL-1α and IL-1β) in IPN induced rats was recorded were as they get significantly (p&lt;0.001) decreased in MA administrated groups of three different doses. Conclusion: The results obtained from the acute toxicity experiment concluded that MA was found to be safe for oral administration. The therapeutic experiment results clearly emphasize the beneficial action of MA against IPN induced MI in rats

A multiscale model for dilute turbulent gas-particle flows based on the equilibration of energy concept

The objective of this study is to improve Eulerian-Eulerian models of particle-laden turbulent flow. We begin by understanding the behavior of two existing models—one proposed by Simonin [von Kármán Institute of Fluid Dynamics Lecture Series, 1996], and the other by Ahmadi [Int. J. Multiphase Flow16, 323 (1990)]—in the limiting case of statistically homogeneous particle-laden turbulent flow. The decay of particle-phase and fluid-phase turbulent kinetic energy (TKE) is compared with direct numerical simulation results. Even this simple flow poses a significant challenge to current models, which have difficulty reproducing important physical phenomena such as the variation of turbulent kinetic energy decay with increasing particle Stokes number. The model for the interphase TKE transfer time scale is identified as one source of this difficulty. A new model for the interphase transfer time scale is proposed that accounts for the interaction of particles with a range of fluid turbulence scales. A new multiphase turbulence model—the equilibration of energy model (EEM)—is proposed, which incorporates this multiscale interphase transfer time scale. The model for Reynolds stress in both fluid and particle phases is derived in this work. The new EEM model is validated in decaying homogeneous particle-laden turbulence, and in particle-laden homogeneous shear flow. The particle and fluid TKE evolution predicted by the EEM model correctly reproduce the trends with important nondimensional parameters, such as particle Stokes number

Classification and disk parameters of Herbig Ae/Be stars using WISE and AKARI data

We present the classification and disk parameters of 50 Herbig Ae/Be stars using WISE and AKARI data. These stars have been classified into 4 groups based on the scheme proposed by Koenig et al. (2012) using WISE pass bands and by constructing their SEDs using data up to 12 pass bands. We could successfully classify 18 sources as Class I, 22 as Class II, 6 as Class III and 4 as sources with transitional disk. One-third of the sample (classification of 14 of 50 and disk parameters of 19 of 50) were studied for the first time. SEDs created with and without AKARI data were found to be similar for a good fraction of sources, though some sources showed large deviation. The SEDs are also used to derive the stellar as well as the circumstellar disk parameters. Our analysis suggests that sources more massive than &#8764;6 M&#x2299; may have a very short Class II phase. We have studied the correlation between various stellar and disk parameters. Among the present sample, this study tentatively suggests that one set of stars are found to lose their disk rapidly, within 3-4 Myr, whereas another set of sources are found to retain their disk as well as accretion till 6-8 Myr

Genome sequence of a novel alloherpesvirus isolated from glass catfish (Kryptopterus bicirrhis)

The 149,343-bp genome of silurid herpesvirus 1, which was isolated in Thailand from glass catfish, was sequenced. The genome was most closely related to that of ictalurid herpesvirus 2, which infects black bullhead catfish. To our knowledge, this was the first silurid catfish alloherpesvirus genome to be sequenced

Pre-main sequence stars, emission stars and recent star formation in the Cygnus Region

The recent star formation history in the Cygnus region is studied using 5 clusters (IC 4996, NGC 6910, Berkeley 87, Biurakan 2 and Berkeley 86). The optical data from the literature are combined with the 2MASS data to identify the pre-main sequence (pre-MS) stars as stars with near IR excess. We identified 93 pre-MS stars and 9 stars with H$_\alpha$ emission spectra. The identified pre-MS stars are used to estimate the turn-on age of the clusters. The duration of star formation was estimated as the difference between the turn-on and the turn-off age. We find that, NGC 6910 and IC 4996 have been forming stars continuously for the last 6 -- 7 Myr, Berkeley 86 and Biurakan 2 for 5 Myr and Berkeley 87 for the last 2 Myr. This indicates that the Cygnus region has been actively forming stars for the last 7 Myr, depending on the location. 9 emission line stars were identified in 4 clusters, using slit-less spectra (Be 87 - 4 stars; Be 86 - 2 stars, NGC 6910 - 2 stars and IC 4996 - 1 star). The individual spectra were obtained and analysed to estimate stellar as well as disk properties. All the emission stars are in the MS, well below the turn-off, in the core hydrogen burning phase. These stars are likely to be Classical Be (CBe) stars. Thus CBe phenomenon can be found in very young MS stars which are just a few (2 -- 7) Myrs old. This is an indication that CBe phenomenon need not be an evolutionary effect.Comment: 37 pages, 20 figure

Spectroscopic study of a few Herbig Ae/Be stars in young open clusters

We present the spectroscopic study of 5 Herbig Ae/Be stars in young open clusters. These are identified from a survey of emission-line stars in young open clusters. The Herbig Ae/Be stars are found to show a linear correlation in Hα equivalent width versus reddening corrected (H−Ks) colour plot, with a clear offset from the distribution of Classical Be stars. The candidates are found to show near infrared excess which was revealed through de-reddened (J−H) versus (H−Ks) colour-colour diagram and spectral energy distribution. From optical/near-IR photometry and spectroscopy, we suggest that Bochum 6-1, IC 1590-1 and NGC 6823-1 are Herbig Be while IC 1590-2 and NGC 7380-4 are Herbig Ae candidates. Bochum 6-1 is an interesting Herbig B[e] star with a high Hα equivalent width of −206&#197;, which is the highest among the A surveyed stars. We combined the optical and near-IR photometry to estimate the duration of star formation in the clusters, Bochum 6, IC 1590, NGC 6823 and NGC 7380. We found ongoing star formation in all these clusters, with an appreciable number of pre-main sequence stars. The age of these Herbig Ae/Be stars, estimated using pre-main sequence isochrones, were found to range between 0.25−3 Myr. IC 1590 is found to be an interesting young cluster (∼ 4 Myr) with 3 emission stars, each belonging to Herbig Ae, Herbig Be and Classical Be respectively. All the four clusters studied here were found to be forming stars for the last 10 Myr

Setting Real Time WIP Levels in Production Lines

A new algorithm is developed for setting WIP level in production lines. It is a pull policy that determines when to authorize a job to be processed. Dynamic information in the system such as machine failures and repairs, and demand variations are taken into consideration to provide an efficient method to dynamically determine the WIP level. Two types of production lines are examined in this paper. The first is production lines which have few random interruptions and the second production line is exposed to frequent interruptions. Experiment results from these two types of production lines illustrate that the new algorithm generates higher service level with lower WIP compared to the CONWIP policy. In addition, the superiority of the new algorithm is more significant when the production line is exposed to frequent random interruptions.Singapore-MIT Alliance (SMA

Influence of convex and concave curvatures in a coastal dike line on wave run-up

Due to climatic change and the increased usage of coastal areas, there is an increasing risk of dike failures along the coasts worldwide. Wave run-up plays a key role in the planning and design of a coastal structure. Coastal engineers use empirical equations for the determination of wave run-up. These formulae generally include the influence of various hydraulic, geometrical and structural parameters, but neglect the effect of the curvature of coastal dikes on wave run-up and overtopping. The scope of this research is to find the effects of the dike curvature on wave run-up for regular wave attack by employing numerical model studies for various dike-opening angles and comparing it with physical model test results. A numerical simulation is carried out using DualSPHysics, a mesh-less model and OpenFOAM, a mesh-based model. A new influence factor is introduced to determine the influence of curvature along a dike line. For convexly curved dikes (ad = 210° to 270°) under perpendicular wave attack, a higher wave run-up was observed for larger opening angles at the center of curvature whereas for concavely curved dikes (ad = 90° to 150°) under perpendicular wave attack, wave run-up increases at the center of curvature as the opening angle decreases. This research aims to contribute a more precise analysis and understanding the influence of the curvature in a dike line and thus ensuring a higher level of protection in the future development of coastal structures.Peer ReviewedPostprint (published version