7,006 research outputs found

    The suitability of various spacecraft for future space applications missions

    Get PDF
    The Space Applications Advisory Committee (SAAC) of NASA's Advisory Council was asked by the Associate Administrator for Space Science and Applications to consider the most suitable future means for accomplishing space application missions. To comply with this request, SAAC formed a Task Force whose report is contained in this document. In their considerations, the Task Force looked into the suitability of likely future spacecraft options for supporting various types of application mission payloads. These options encompass a permanent manned space station, the Space Shuttle operating in a sortie mode, unmanned platforms that integrate a wide variety of instruments or other devices, and smaller free fliers that accommodate at most a few functions. The Task Force also recognized that the various elements could be combined to form a larger space infrastructure. This report summarizes the results obtained by the Task Force. It describes the approach utilized, the findings and their analysis, and the conclusions

    Coping Ability of Medical and Nursing Students: A Cause of Concern

    Get PDF
    Background: Medical students today are subject to a variety of stress; academic, social, emotional or stress in the form of affliction of health during their stay at medical school. The physiological response to these depends on various factors including their inherent coping abilities. This study was designed to examine the coping ability of medical and nursing students at the time of admission to medical school. Materials and Methods: 42 medical and 34 nursing students volunteered for the study. They were administered the BAI questionnaire and classified as good and poor adjusters based on their score. Results: The study revealed an unsatisfactory overall coping ability to be prevalent among medical and nursing students. Conclusion: This study showed that there is a need for orientation and counselling of medical and nursing students at the start of college

    Harvest index of lupins, Low tillering cereals and Maturity by sowing date in cereals.

    Get PDF
    Trial 87GE21 Effect of plant density on branching, pod setting and yield development of lupins. Location: Geraldton To determine the influence of plant density and between-plant variability in vegetative growth on the branching, pod setting and yield development of lupins Trial 87GE9 Chemicals to control vegetative growth and improve pod set in lupins. Location: West Binnu To examine the effect of a number of growth regulating chemicals on the branching, pod setting and yield of lupins under conditions favoring high biomass production. Trial 87GE19 Chemicals to control vegetative growth and improve pod set in lupins. Location: Nabawa To examine the effect of a number of growth regulating chemicals on the branching, pod setting and yield of lupins under conditions favouring high biomass production. Trial 87GE72 Effect of plant density on growth and yield of lupins. Location: South Yuna To determine the influence of plant density on the growth, branching, pod setting and yield development of branching and reduced branching lupins under conditions producing different levels of biomass Trial 87E34 Effect of sowing time on yield of lupin varieties. Location: Esperance Downs Research Station. Lupins are well adapted to the cooler, long-season environments of the southern coastal sandplain. of Western Australia. This trial aims to help establish varietal characteristics required to produce high-yielding lupin crops in the cool, long-season environment of southern Australia. The specific aim is to determine the influence of sowing date on the growth and yield of lupin varieties differing in maturity and branching habit in the south-coast environment. LVT Sampling - 1986 and 1987 seasons - Effect of genotype and environment on growth, yield components, harvest index and yield of lupins. Low harvest index (H.I.) is often suggested as the cause of poor lupin seed yields, and it is argued that all vegetative lupin crops have inherently poor pod set and low harvest index. By sampling LVT\u27s across a wide range of sites in 1986 and selected sites in 1987, we aimed to determine the effect of environment on lupin growth, branching, seed yield, H.I. and yield components. Sampling of two branching genotypes and a reduced branching line would permit the assessment of genotypic effects and any G x E interactions. Trial 87C66 Effect of maturity and sowing date on wheat and barley. Location Chapman Research Stations Two similar trials at North Mullewa and East Chapman were not harvested due to severe drought and high weed populations, respectively. Dr J. Hamblin\u27s summary reports the results of three further sowing date trials

    DCO+^+, DCN and N2_2D+^+ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296

    Get PDF
    The formation pathways of deuterated species trace different regions of protoplanetary disks and may shed light into their physical structure. We aim to constrain the radial extent of main deuterated species; we are particularly interested in spatially characterizing the high and low temperature pathways for enhancing deuteration of these species. We observed the disk surrounding the Herbig Ae star HD 163296 using ALMA in Band 6 and obtained resolved spectral imaging data of DCO+^+ (JJ=3-2), DCN (JJ=3-2) and N2_2D+^+ (JJ=3-2). We model the radial emission profiles of DCO+^+, DCN and N2_2D+^+, assuming their emission is optically thin, using a parametric model of their abundances and radial excitation temperature estimates. DCO+^+ can be described by a three-region model, with constant-abundance rings centered at 70 AU, 150 AU and 260 AU. The DCN radial profile peaks at about ~60 AU and N2_2D+^+ is seen in a ring at ~160 AU. Simple models of both molecules using constant abundances reproduce the data. Assuming reasonable average excitation temperatures for the whole disk, their disk-averaged column densities (and deuterium fractionation ratios) are 1.6-2.6×1012\times 10^{12} cm−2^{-2} (0.04-0.07), 2.9-5.2×1012\times 10^{12} cm−2^{-2} (∼\sim0.02) and 1.6-2.5 ×1011\times 10^{11} cm−2^{-2} (0.34-0.45) for DCO+^+, DCN and N2_2D+^+, respectively. Our simple best-fit models show a correlation between the radial location of the first two rings in DCO+^+ and the DCN and N2_2D+^+ abundance distributions that can be interpreted as the high and low temperature deuteration pathways regimes. The origin of the third DCO+^+ ring at 260 AU is unknown but may be due to a local decrease of ultraviolet opacity allowing the photodesorption of CO or due to thermal desorption of CO as a consequence of radial drift and settlement of dust grains

    Environmental determinants of acute respiratory symptoms and diarrhoea in young coloured children living in urban and peri-urban areas of South Africa

    Get PDF
    The impact of environmental risk factors associated with housing was examined in relation to diarrhoeal disease and acute respiratory symptoms in South African coloured children. A multistage cluster sample representative of all coloured people living in the major urban and peri-urban areas of South Africa was used for the study. Interviews were conducted with respondents from 1 227 households. Overall, 8,5% children under 5 years were reported to have had diarrhoea, while 29% had experienced coughing and breathing problems in a 2-week recall period. Individual risk factors identified using the odds ratios (ORs) for diarrhoea included not having an inside tap or a flush toilet in the homes (both yielded an OR of 3,3), not owning a refuse receptacle (OR = 2,5), not being connected to an electricity supply (OR = 2,5), low household income (OR = 1,8), more than 2 people per room (OR = 2,0) and less than Standard 5 maternal education (OR = 1,6). Absence of an inside toilet, not having a refuse receptacle and overcrowding all remained as independent risk factors after logistic regression analyses. Multiple logistic regression analyses revealed that not having a refuse receptacle and the absence of electricity for heating purposes were independently associated with respiratory symptoms. The overall preventive potentials for respiratory symptoms were significantly less than those for diarrhoea. Improving physical access to essential environmental health services in urban areas and improvements in the educational status of women are urgently needed if childhood infections are to be prevented

    Exploring DCO+^+ as a tracer of thermal inversion in the disk around the Herbig Ae star HD163296

    Get PDF
    We aim to reproduce the DCO+^+ emission in the disk around HD163296 using a simple 2D chemical model for the formation of DCO+^+ through the cold deuteration channel and a parametric treatment of the warm deuteration channel. We use data from ALMA in band 6 to obtain a resolved spectral imaging data cube of the DCO+^+ JJ=3--2 line in HD163296 with a synthesized beam of 0."53×\times 0."42. We adopt a physical structure of the disk from the literature that reproduces the spectral energy distribution. We then apply a simplified chemical network for the formation of DCO+^+ that uses the physical structure of the disk as parameters along with a CO abundance profile, a constant HD abundance and a constant ionization rate. Finally, from the resulting DCO+^+ abundances, we calculate the non-LTE emission using the 3D radiative transfer code LIME. The observed DCO+^+ emission is reproduced by a model with cold deuteration producing abundances up to 1.6×10−111.6\times 10^{-11}. Warm deuteration, at a constant abundance of 3.2×10−123.2\times 10^{-12}, becomes fully effective below 32 K and tapers off at higher temperatures, reproducing the lack of DCO+^+ inside 90 AU. Throughout the DCO+^+ emitting zone a CO abundance of 2×10−72\times 10^{-7} is found, with ∼\sim99\% of it frozen out below 19 K. At radii where both cold and warm deuteration are active, warm deuteration contributes up to 20\% of DCO+^+, consistent with detailed chemical models. The decrease of DCO+^+ at large radii is attributed to a temperature inversion at 250 AU, which raises temperatures above values where cold deuteration operates. Increased photodesorption may also limit the radial extent of DCO+^+. The corresponding return of the DCO+^+ layer to the midplane, together with a radially increasing ionization fraction, reproduces the local DCO+^+ emission maximum at ∼\sim260 AU.Comment: 9 pages, 5 figures, accepted 7th July 201
    • …
    corecore