673 research outputs found
The agriculture-industry continuum
This is a very condensed examination of the reciprocal interactions
between agriculture and industry in the development process. It is argued that
today's 'late developing countries' -- those characterised by an economic structure
in which agriculture still accounts for some 60 to 80 per cent of the country's
total labour force and by rapid rates of growth of both population and labour force
-- confront special problems and opportunities. One consequence of those structural/
demographic characteristics is that the nature and time sequence of farm innovations
will determine the proportion of a country's farmers that is able to participate
in the process of agricultural modernisation. And whether or not a country's agricultural
strategy leads to wide participation of the rural population in technical
and economic advance has major implications for the achievement of both the economic
and social goals of national development
Objectives and scope of a food and nutrition policy
This general paper suggests that the scope of a country's food and
nutrition policy should embrace three related objectives: (1) the design and
implementation of an agricultural strategy that achieves an appropriate rate
and pattern of expansion of food and other farm products; (2) action to bring
nutritional objectives to bear in influencing the combination of foods produced
and the processing techniques employed; and (3) the identification and
implementation of supplementary programmes of nutrition intervention aimed
directly at certain important welfare objectives, such as overcoming nutritional
deficiencies that may be common among some segments of the under-five age group.
Principal emphasis is given in this, paper to the first objective. It is argued
that an agricultural strategy that brings about the progressive modernisation
of a large and increasing fraction of a country's farm households is fundamental
to the success of efforts to promote overall economic growth and structural
transformation as well as achieving the social goals of employment creation,
better income distribution, and improvements in nutrition and health
A Search for the Optical Counterpart of the Luminous X-ray Source in NGC 6652
We examine images of the field of X1832-330, the luminous (Lx ~ 10^36 erg/s)
X-ray burst source near the center of the globular cluster NGC 6652, in order
to identify the optical counterpart for further study. U and B ground-based
images allow us to set a limit M_B > 3.5 for the counterpart at the time of
those observations, provided that the color is (U-B)_0 ~ -1, similar to the
sources known in other clusters. Archival Hubble Space Telescope observations
survey most but not all of the 1 sigma X-ray error circle, and allow us to set
limits M_B > 5.9 and M_B > 5.2 in the WF/PC and WFPC2 regions, respectively. In
the WF/PC images we do weakly detect a faint object with UV-excess, but it is
located 11.7'' from the ROSAT X-ray position. This considerable (2.3 sigma)
discrepancy in position suggests that this candidate be treated with caution,
but it remains the only reasonable one advanced thus far. We measure for this
star m_439 = 20.2 +- 0.2, (m_336 - m_439) = -0.5 +- 0.2, and estimate M_B =
5.5, (U-B)_0 = -0.9, similar to other known optical counterparts. If this
candidate is not the identification, our limits imply that the true
counterpart, not yet identified, is probably the optically-faintest cluster
source yet known, or alternatively that it did not show significant UV excess
at the time of these observations. Finally, we assess the outlook for the
identification of the remaining luminous globular cluster X-ray sources.Comment: 15 pages including 5 figures and no tables. Accepted for publication
in The Astronomical Journal; to appear in Volume 116, September 1998. A
preprint with full resolution figures may be downloaded from
http://www.astro.washington.edu/deutsch/pubs
Chandra Observation of the Globular Cluster NGC 6440 and the Nature of Cluster X-ray Luminosity Functions
As part of our campaign to determine the nature of the various source
populations of the low-luminosity globular cluster X-ray sources, we have
obtained a Chandra X-ray Observatory ACIS-S3 image of the globular cluster NGC
6440. We detect 24 sources to a limiting luminosity of ~2 times 10^31 erg/s
(0.5-2.5keV) inside the cluster's half-mass radius, all of which lie within ~2
core radii of the cluster center. We also find excess emission in and around
the core which could be due to unresolved point sources. Based upon X-ray
luminosities and colors, we conclude that there are 4-5 likely quiescent
low-mass X-ray binaries and that most of the other sources are cataclysmic
variables. We compare these results to Chandra results from other globular
clusters and find the X-ray luminosity functions differ among the clusters.Comment: 9 pages, 4 figures, accepted by ApJ, minor changes, added table of
clusters' physical parameter
Space object identification using phase-diverse speckle
Space-object identification from ground-based telescopes is challenging because of the degradation in resolution arising from atmospheric turbulence. Phase-diverse speckle is a novel post-detection correction method that can be used to overcome turbulence-induced aberrations for telescopes with or without adaptive optics. We present a simulation study of phase-diverse speckle satellite reconstructions for the Air Force Maui Optical station 1.6-meter telescope. For a given turbulence strength, satellite reconstruction fidelity is evaluated as a function of quality and quantity of data. The credibility of this study is enhanced by reconstructions from actual compensated data collected with the 1.5-meter telescope at the Starfire Optical Range. Consistent details observed across a time series of reconstructions from a portion of a satellite pass enhance the authenticity of these features. We conclude that phase-diverse speckle can restore fine-resolution features not apparent in the raw aberrated images of space objects
Outcomes of less invasive J-incision approach to aortic valve surgery
ObjectiveLess invasive approaches to aortic valve surgery are increasingly used; however, few studies have investigated their impact on outcome. We sought to compare clinical outcomes after these approaches with full sternotomy using propensity-matching methods.MethodsFrom January 1995 to January 2004, a total of 2689 patients underwent isolated aortic valve surgery, 1193 via upper J-hemisternotomy and 1496 via full sternotomy. Because of important differences in patient characteristics between these groups, a propensity score based on 42 variables was used to obtain 832 well-matched patient pairs (70% of possible cases).ResultsIn-hospital mortality was identical for propensity-matched patients, 0.96% (8 in each). Occurrences of stroke (P > .9), renal failure (PÂ =Â .8), and myocardial infarction (PÂ =Â .7) were similar. However, 24-hour mediastinal drainage was a third less after less invasive surgery (median, 250 vs 350 mL; P < .0001), and fewer patients received transfusions (24% vs 34%; P < .0001). More patients undergoing less invasive surgery were extubated in the operating room (12% vs 1.6%; P < .0001), postoperative forced 1-second expiratory volume was higher (PÂ =Â .009), and fewer had respiratory failure (PÂ =Â .01). Early after operation, pain scores were lower (P < .0001) after less-invasive surgery and postoperative length of stay shorter (PÂ <Â .0001).ConclusionsWithin that portion of the spectrum of isolated aortic valve surgery where propensity matching was possible, minimally invasive aortic valve surgery had not only cosmetic advantages, but blood product use, respiratory, pain, and resource utilization advantages over full sternotomy, and no apparent detriments. Less invasive aortic valve surgery should be considered for most aortic valve operations
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