Simulation of old open clusters for UVIT on ASTROSAT

Ultra Violet Imaging Telescope (UVIT) is one of the payloads on the first Indian multi wavelength satellite ASTROSAT expected to be launched by Indian Space Research Organisation (ISRO) in the year 2015. We have performed simulations of UV studies of old open clusters for the UVIT. The colour magnitude diagrams (CMDs) and spatial appearances have been created using 10 filters of FUV channel (130 - 180 nm) and NUV channel (200 - 300nm) available for observations on the UVIT, for three old open clusters M67, NGC 188 and NGC 6791. The CMDs are simulated for different filter combinations, and they are used to identify the loci of various evolutionary sequences, white dwarfs, blue stragglers, red giants, sub giants, turn off stars and the main sequence of the clusters. The present work helps in identifying the potential area of study in the case of three old open clusters, by considering the availability of filters and the detection limits of the instrument. We also recommend filter combinations, which can be used to detect and study the above mentioned evolutionary stages. The simulations and the results presented here are essential for the optimal use of the UVIT for studies of old open clusters.Comment: Accepted for publication in RAA; 25 pages, 19 figures, 1 tabl

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

Enskog kinetic theory for monodisperse gas–solid flows

The Enskog kinetic theory is used as a starting point to model a suspension of solid particles in a viscous gas. Unlike previous efforts for similar suspensions, the gas-phase contribution to the instantaneous particle acceleration appearing in the Enskog equation is modelled using a Langevin equation, which can be applied to a wide parameter space (e.g. high Reynolds number). Attention here is limited to low Reynolds number flow, however, in order to assess the influence of the gas phase on the constitutive relations, which was assumed to be negligible in a previous analytical treatment. The Chapman–Enskog method is used to derive the constitutive relations needed for the conservation of mass, momentum and granular energy. The results indicate that the Langevin model for instantaneous gas–solid force matches the form of the previous analytical treatment, indicating the promise of this method for regions of the parameter space outside of those attainable by analytical methods (e.g. higher Reynolds number). The results also indicate that the effect of the gas phase on the constitutive relations for the solid-phase shear viscosity and Dufour coefficient is non-negligible, particularly in relatively dilute systems. Moreover, unlike their granular (no gas phase) counterparts, the shear viscosity in gas–solid systems is found to be zero in the dilute limit and the Dufour coefficient is found to be non-zero in the elastic limit

A comparison of lung function in pranayama trained and untrained medical students

Background: Pranayama is a form of breathing exercise. It is a very useful in reducing the weight and improving the respiratory function. The study was designed to assess the effect of pranayama on pulmonary Function among adult male students.Methods: The control and the study groups each consisted of 50 number of male MBBS students aged between 16 to 22 years, studying at Madras Medical College, were recruited for the present study. The study group were taught pranayama and allowed to practice it daily twice in morning and evening for 15 minutes for 10 weeks under supervision. Parameters like weight, BMI, chest expansion, respiratory rate and spirometric parameters like FVC, FEV1 and PEFR were recorded before and after the study.Results: A significant increase in chest expansion, FVC, FEV1 and PEFR with p value <0.05were recorded in study group in comparison with control group.Conclusions: Pranayama improves the lung function among medical students

Insights into the spectral versatility of fluorescent proteins by single molecule spectroscopy

Understanding the photophysics of fluorescent proteins is essential for accurate interpretation of the biological and biochemical processes illuminated by the fluorescent proteins as well as for the development of biosensors based on fluorescent proteins.We used spectrally resolved single molecule spectroscopy to analyse aspects of fluorescent protein photophysics that are not accessible by conventional ensemble spectroscopy. We were able to identify and characterize different subensembles and spectral forms of a range of fluorescent proteins. We could follow transitions between the different spectral forms on the single molecule level and draw conclusions on the underlying molecular origins. Fluorescent proteins are excellent systems to analyze the interaction between a chromophore and its nanoenvironment since the local environment of the emitting chromophore is precisely defined by the protein that encapsulates the chromophore. We find that for the fluorescent proteins studied, the width of the distribution of the single molecule emission maximum positions is strictly correlated with the flexibility of the chromophore nanoenvironment. Further we analyzed the fluorescence resonance energy transfer coupling of different chromophores within one protein tetramer. We find that in a fraction of the tetramers the different chromophores are not effectively coupled. We propose an interruption of the energy transfer chain within the multichromophoric system by proteins lacking a chromophore

Violent Hiccups: An Infrequent Cause of Bradyarrhythmias

A hiccup, or singultus, results from a sudden, simultaneous, vigorous contraction of the diaphragm and inspiratory muscles, accompanied by closure of the glottis. Hiccups can be associated with bradyarrhythmias. The mechanism of this phenomenon is likely hiccup-induced Valsalva maneuver and increased parasympathetic tone. We present a case of a patient with violent hiccups producing a bradyarrhythmia

Septal Pouch in the Left Atrium A New Anatomical Entity With Potential for Embolic Complications

ObjectivesThe purpose of this study was to develop a better understanding of the pathophysiology of the condition, we studied the patterns by which the septum primum (SP) and septum secundum (SS) fuse.BackgroundA patent foramen ovale (PFO) is a communication across the interatrial septum between a nonadherent SP and SS and is considered to be a risk factor for serious clinical syndromes.MethodsWe examined the interatrial septum in 94 randomly selected autopsied hearts, with a focus on the SP and SS and the patterns by which the 2 structures fuse.ResultsOf the 94 specimens that were suitable for analysis, 26 (27.66%) had a PFO. Of the remaining 68 hearts, complete fusion of the SP and SS along the entire zone of overlap was seen in 27 (28.7%) hearts. In the remaining 41 hearts (60.29%), a PFO was absent, but incomplete fusion of the SP and SS was seen. Of 41 hearts, 37 (90%) had a septal pouch that opened into the left atrial (LA) cavity. Four hearts (10%) had a pouch accessible from the right atrium. Hearts with left-sided pouches tended to be younger (50 ± 18 years of age) than hearts where there was complete fusion (age 63 ± 23 years) (p = 0.06).ConclusionsOur data suggest that when a foramen ovale closes spontaneously, the SP and SS fuse initially at the caudal limit of the zone of overlap of the 2 structures. This incomplete fusion results in a pouch that, in the majority of instances, communicates with the LA cavity

Anatomical Basis for the Mobility of the Esophagus: Implications for Catheter Ablation of Atrial Fibrillation

We present autopsy data from a patient that illustrates the anatomical factors that allow the esophagus to be a mobile structure, especially with respect to the posterior left atrial wall

Searching for the Least Invasive Management of Pelvi-Ureteric Junction Obstruction in Children: A Critical Literature Review of Comparative Outcomes

Introduction: To review the published evidence on the minimally invasive pyeloplasty techniques available currently with particular emphasis on the comparative data about the various minimally invasive alternatives to treat pelvi-ureteric junction obstruction and gauge if one should be favored under certain circumstances. Materials and Methods: Non-systematic review of literature on open and minimally invasive pyeloplasty including various kinds of laparoscopic procedures, the robotic-assisted laparoscopic pyeloplasty, and endourological procedures. Results: Any particular minimally invasive pyeloplasty procedure seems feasible in experienced hands, irrespective of age including infants. Comparative data suggest that the robotic-assisted procedure has gained wider acceptance mainly because it is ergonomically more suited to surgeon well-being and facilitates advanced skills with dexterity thanks to 7 degrees of freedom. However, costs remain the major drawback of robotic surgery. In young children and infants, instead, open surgery can be performed via a relatively small incision and quicker time frame. Conclusions: The best approach for pyeloplasty is still a matter of debate. The robotic approach has gained increasing acceptance over the last years with major advantages of the surgeon well-being and ergonomics and the ease of suturing. Evidence, however, may favor the use of open surgery in infancy