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The Molonglo Observatory Synthesis Telescope (MOST) is an 18000 m2 radio telescope located 40 km from Canberra, Australia. Its operating band (820–851 MHz) is partly allocated to telecommunications, making radio astronomy challenging. We describe how the deployment of new digital receivers, Field Programmable Gate Array-based filterbanks, and server-class computers equipped with 43 Graphics Processing Units, has transformed the telescope into a versatile new instrument (UTMOST) for studying the radio sky on millisecond timescales. UTMOST has 10 times the bandwidth and double the field of view compared to the MOST, and voltage record and playback capability has facilitated rapid implementaton of many new observing modes, most of which operate commensally. UTMOST can simultaneously excise interference, make maps, coherently dedisperse pulsars, and perform real-time searches of coherent fan-beams for dispersed single pulses. UTMOST operates as a robotic facility, deciding how to efficiently target pulsars and how long to stay on source via real-time pulsar folding, while searching for single pulse events. Regular timing of over 300 pulsars has yielded seven pulsar glitches and three Fast Radio Bursts during commissioning. UTMOST demonstrates that if sufficient signal processing is applied to voltage streams, innovative science remains possible even in hostile radio frequency environments.
The class of radio transients called Fast Radio Bursts (FRBs) encompasses enigmatic single pulses, each unique in its own way, hindering a consensus for their origin. The key to demystifying FRBs lies in discovering many of them in order to identity commonalities – and in real time, in order to find potential counterparts at other wavelengths. The recently upgraded UTMOST in Australia, is undergoing a backend transformation to rise as a fast transient detection machine. The first interferometric detections of FRBs with UTMOST, place their origin beyond the near-field region of the telescope thus ruling out local sources of interference as a possible origin. We have localised these bursts to much better than the ones discovered at the Parkes radio telescope and have plans to upgrade UTMOST to be capable of much better localisation still.
The effects of fragmentation and overstorey tree diversity on tree regeneration were assessed in tropical rain forests of the Western Ghats, India. Ninety plots were sampled for saplings (1–5 cm diameter at breast height (dbh); 5×5-m plots) and overstorey trees (>9.55 cm dbh; 20×20-m plots) within two fragments (32 ha and 18 ha) and two continuous forests. We tested the hypotheses that fragmentation and expected seed-dispersal declines (1) reduce sapling densities and species richness of all species and old-growth species, and increase recruitment of early-successional species, (2) reduce the prevalence of dispersed recruits and (3) increase influence of local overstorey on sapling densities and richness. Continuous forests and fragments had similar sapling densities and species richness overall, but density and richness of old-growth species declined by 62% and 48%, respectively, in fragments. Fragments had 39% lower densities and 24% lower richness of immigrant saplings (presumed dispersed into sites as conspecific adults were absent nearby), and immigrant densities of old-growth bird-dispersed species declined by 79%. Sapling species richness (overall and old-growth) increased with overstorey species richness in fragments, but was unrelated to overstorey richness in continuous forests. Our results show that while forest fragments retain significant sapling diversity, losses of immigrant recruits and increased overstorey influence strengthen barriers to natural regeneration of old-growth tropical rain forests.
To evaluate the inter-fraction variation in interstitial high-dose-rate (HDR) brachytherapy. To assess the positional displacement of catheters during the fractions and the resultant impact on dosimetry.
Although brachytherapy continues to be a key cornerstone of cancer care, it is clear that treatment innovations are needed to build on this success and ensure that brachytherapy continues to provide quality care for patients. The dosimetric advantages offered by HDR brachytherapy to the tumour volume rely on catheter positions being accurately reproduced for all fractions of treatment.
Materials and methods
A total of 66 patients treated over a period of 22 months were considered for this study. All the patients underwent computer tomography (CT) scan and three-dimensional treatment planning was carried out. Brachytherapy treatment was delivered by the HDR afterloading system. On completing the last fraction, CT scan was repeated and treatment re-planning was done. The variation in position of the implanted applicators and their impact on dosimetric parameters were analysed using both the plans.
For all breast-implant patients, the catheter displacement and D90 dose to clinical target volume were <3 mm and 3%, respectively. The displacement for carcinoma of the tongue, carcinoma of the buccal mucosa, carcinoma of the floor of mouth, carcinoma of the cervix, soft-tissue sarcoma and carcinoma of the lip were comparatively high.
Inter-fraction errors occur frequently in interstitial HDR brachytherapy. If no action is taken, it will result in a significant risk of geometrical miss and overdose to the organs at risk. It is not recommended to use a single plan to deliver all the fractions. Imaging is recommended before each fraction and decision on re-planning must be taken.
India occupies 2nd position in the world with a total fruit production of 42 million tonnes. Papaya (Carica papaya) fruit production in India is 1.3 million tonnes. After extraction of juice from fruit, around 25-30% of the processed fruit is left as waste containing skins and seeds, called as papaya pomace. Generally this goes as a waste causing environmental pollution and if utilized properly will contribute to national economy and reduce pollution effect. Available information on chemical composition and utilization of papaya skins in feeding growing pullets (Fouzder et al., 1999) indicate the potential value of papaya pomace for animal feeding. In view of paucity of information on papaya pomace utilization in animal feeding, an attempt was made to study the effect of inclusion of varying levels of papaya pomace in concentrate mixtures on the nutrient utilization in native male buffaloes.
In a 30-ha permanent plot of tropical evergreen forest at Varagalaiar, Indian Western Ghats, all trees ≥
30 cm girth at breast height (gbh) were examined for the presence of lianas ≥ 1 cm dbh. The plot contained 13 445
trees in 152 species and 11 200 lianas in 75 species. Twenty-eight per cent of trees supported lianas and the mean
number of lianas per tree was 0.38 ± 0.72. Association analysis between lianas and trees of 16 tree families and 20
abundant tree species indicated that tree susceptibility to lianas was better pronounced at species rather than at family
level. Overall, at Varagalaiar site, the aggregation of lianas followed neither Poisson nor clumped distribution. Among
the four dominant tree families Dipterocarpaceae and Clusiaceae fit to the negative binomial model better than Euphorbiaceae and Meliaceae. These four families differed in their susceptibility level with 34.6% , 36.7% , 24.1% and 27.7%
of trees ≥ 30 cm gbh respectively supporting lianas. At the species level, the proportion of trees with lianas was
positively correlated with the mean branch free bole height of trees ≥ 30-40 and ≥ 40 cm gbh classes, and the mean
number of lianas per tree was also positively correlated with the mean branch bole height of trees ≥ 30 cm gbh. Of
the 16 abundant families, Euphorbiaceae contributed 31% and dominated the lower canopy, but its susceptibility to
lianas was lower when compared to most other families.
The crystal structure of a covalently cross-linked
Lactobacillus casei thymidylate synthase has been
determined at 2.8 Å resolution. The sites for mutation
to achieve the bis-disulfide linked dimer were identified
using the disulfide modeling program MODIP. The mutant
so obtained was found to be remarkably thermostable. This
increase in stability has been reasoned to be entirely
a consequence of the covalent gluing between the two subunits.
Munjal is a mutton-type sheep found in some districts of the Haryana, Punjab and Rajasthan states. A sample survey was conducted in two districts of Rajasthan and one district of Punjab to record characteristics of Munjal sheep. Information was recorded on morphological characteristics, body measurements and body weight. Munjal sheep are quite big in size, tall, rectangular and massive with a dark brown face. Measurements were recorded of body length, height, heart girth, paunch girth, ear length and tail length. Adult body weights were also recorded. Wool samples were collected and analysed for their quality attributes. Wool from this breed is very coarse and hairy.
SAO 244567 (= Hen 1357) is a very young planetary nebula. It was discovered by Parthasarathy et al. (1993, A and A 267, L19). Based on the spectrum obtained around 1950 Henize (1976, ApJ Suppl 30, 491) classified it as a B or A type H-alpha emission line star. The optical spectrum of SAO 244567 obtained in 1971 shows that it was a post-AGB B1 supergiant at that time. It has turned into a planetary nebula within the last 20 years (Parthasarathy et al. 1995, A and A 300, L25).
A study of two-layer quasi-geostrophic vortex flow is performed to determine the effect of a current difference between the layers on a vortex initially extending through both layers. In particular, the conditions under which the vortex can resist being torn by the current difference are examined. The vortex evolution is determined using versions of the contour dynamics and discrete vortex methods which are modified for two-layer quasi-geostrophic flows. The vortex response is found to depend upon the way in which the current difference between the layers is maintained. In the first set of flows studied, the current difference is generated by a (stronger) third vortex in the upper layer located at a large distance from the (weaker) vortex under study. Flows of this type are important for understanding the interactions of vortices of different sizes in geophysical turbulence. A set of flows is also considered in which an ambient geostrophic current difference is produced by a non-uniform background potential vorticity field. In this case, an additional (secondary) flow field about the vortex patch in each layer is generated by redistribution of the ambient potential vorticity field.
It is found that a vortex that initially extends through both layers will undergo a periodic motion, in which the two parts of the initial vortex in the different layers (called the ‘upper’ and ‘lower’ vortices) oscillate about each other, provided that the current difference between the layers is less than a critical value. When the current difference exceeds this critical value, the upper and lower vortices separate permanently and the initial vortex is said to ‘tear’. The effects of various dimensionless parameters that characterize the flow are considered, including the ratio of core radius to internal Rossby radius, the ratio of layer depths and the ratio of the strengths of the upper and lower vortices. These parameters affect both the critical current difference for tearing and the deformation of the vortex cores by their interaction. It is found that for small values of inverse internal Rossby deformation radius, calculations with circular non-deformable vortices (convected at their centrepoints) give results in good agreement with the contour dynamics simulations, since the vortex deformation is small. The results of the study will be useful in determining the conditions under which large geophysical vortex structures, such as cyclones and ocean rings, can extend to large heights (depths) even though the mean winds (currents) in the ambient flow change significantly along the vortex length.
The variation of resistivity of the lithium fast-ion conductor Li3+y Ge1−yO4 (y = 0.25, 0.6, 0.72) has been studied with hydrostatic pressure up to 70 kbar and compared with that of Li16−2x Znx (GeO4)4(x = 1, 2). Both types showed pronounced resistivity maxima between 20–30 kbar and marked decrease thereafter. Measurements as a function of temperature between 120–300 K permitted the determination of activation energies and prefactors that also showed corresponding maxima. The activation volumes (ΔV) of the first type of compound varied between 4.34 to −4.90 cm3/mol at 300 K and decreased monotonically with increasing temperature. For the second type ΔV was much smaller, varied with pressure between 0.58 and −0.24 cm3/mol, and went through a maximum with increasing temperature. High-pressure studies were also conducted on aged samples, and the results are discussed in conjunction with results of impedance measurements and nuclear magnetic resonance (NMR) studies. The principal effect of pressure appears to be variations of the sum of interatomic potentials and hence barrier height, which also causes significant changes in entropy.
In presenting experimental results on turbulent wall jets, most workers have adopted as basic scales the slot height b and jet exit velocity Uj. Although this is a natural choice, experience with other flows like jets and boundary layers, where the details of the initial conditions are eventually (if not always rapidly) forgotten by the flow, prompts the question: cannot a gross parameter like the jet momentum flux Mj rather than Uj and b separately, suffice to determine the flow, at least in some region where the wall jet may be said to have attained a “fully-developed” state? If the answer to the question is yes, it would give a more compact and practically useful description of the flow than is currently available.
It has been suggested that the experimentally observed orientation dependence of the mobility of grain boundaries in f.c.c. metals may be related to the dependence of the rate of self diffusion in grain boundaries on the disorientation across the boundary. Later, this relative orientation effect on the rate of boundary diffusion and self diffusion was experimentally observed. It was shown by Hoffman and Turnbull that in bicrystals of silver misoricnted around (100) by 9° to 28°, self diffusion along the boundary (parallel to the common (100)) may be described in terms of a coefficient of self diffusion in individual grain boundary edge dislocation pipes, orders of magnitude larger than the coefficient of lattice self diffusion. It is significant that the coefficient of self diffusion in grain boundary dislocation pipes was found to be independent of the misorientation (i.e., of the density of edge dislocations in the boundary) at least up to 28°, suggesting that even a boundary of such a great misorientation may be considered as a network of dislocations, as far as self diffusion is concerned.
In recent experiments the relative mobilities of boundaries in various orientations between a deformed (99.98% pure) aluminum single crystal and recrystallized grains growing in it in fairly well defined, lattice orientation relationships were compared. The matrix crystal was rolled to 80% R.A. on a (110) plane in a  direction, after which the strip still retained its initial orientation and the texture was very sharp. Recrystallized grains quite accurately oriented so as to have highest overall boundary mobility, i.e., corresponding to 40° rotations around the two 111 axes of the matrix grain lying in the rolling plane, were produced in large numbers by random nucleation on one side of the strip (rubbing one side with sandpaper and annealing). The re crystallized grains, that were at first growing in very large numbers and quite randomly but only in the thin surface layer highly deformed by abrasion (nucleation side), on annealing for 600 sec at 350°C grew across the whole thickness (0,010″) of the rolled single crystal. As a result of very selective growth, the recrystallized grains reaching the other side of the strip (growth side) showed a very sharp texture consisting of four components with the orientations described.
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