9,041 research outputs found
Astrophysical properties of binary star clusters in the Small Magellanic Cloud
To study the evolution of binary star clusters we have imaged 7 systems in
the Small Magellanic Cloud with SOAR 4-m telescope using B and V filters. The
sample contains pairs with well-separated components (d < 30 pc) as well as
systems that apparently merged, as evidenced by their unusual structures. By
employing isochrone fittings to their CMDs we have determined reddening, age
and metallicity and by fitting King models to their radial stellar density
profile we have estimated core radius. Disturbances of the density profile are
interpreted as an evidence of interaction. Circunstances as distances between
components and their age difference are addressed in terms of the timescales
involved to access the physical connection of the system. In two cases the age
difference is above 50 Myr, which suggests chance alignment, capture or
sequential star formation.Comment: 4 pages, 1 figure. To appear in online version of Proc. IAU Symp. 266
(Star clusters), eds. R. de Grijs and J. Lepin
Convex Trace Functions on Quantum Channels and the Additivity Conjecture
We study a natural generalization of the additivity problem in quantum
information theory: given a pair of quantum channels, then what is the set of
convex trace functions that attain their maximum on unentangled inputs, if they
are applied to the corresponding output state?
We prove several results on the structure of the set of those convex
functions that are "additive" in this more general sense. In particular, we
show that all operator convex functions are additive for the Werner-Holevo
channel in 3x3 dimensions, which contains the well-known additivity results for
this channel as special cases.Comment: 9 pages, 1 figure. Published versio
Effects of winglet on transonic flutter characteristics of a cantilevered twin-engine-transport wing model
A transonic model and a low-speed model were flutter tested in the Langley Transonic Dynamics Tunnel at Mach numbers up to 0.90. Transonic flutter boundaries were measured for 10 different model configurations, which included variations in wing fuel, nacelle pylon stiffness, and wingtip configuration. The winglet effects were evaluated by testing the transonic model, having a specific wing fuel and nacelle pylon stiffness, with each of three wingtips, a nonimal tip, a winglet, and a nominal tip ballasted to simulate the winglet mass. The addition of the winglet substantially reduced the flutter speed of the wing at transonic Mach numbers. The winglet effect was configuration-dependent and was primarily due to winglet aerodynamics rather than mass. Flutter analyses using modified strip-theory aerodynamics (experimentally weighted) correlated reasonably well with test results. The four transonic flutter mechanisms predicted by analysis were obtained experimentally. The analysis satisfactorily predicted the mass-density-ratio effects on subsonic flutter obtained using the low-speed model. Additional analyses were made to determine the flutter sensitivity to several parameters at transonic speeds
The standardisation and use of performance tests of intelligence under Indian conditions, including illiterates
We have. In the first chapter of this work,
started with the desirability and necessity of having
Intelligence tests, particularly in those countries
which are yet undeveloped. We have then discussed
the problems of Intelligence testing in India in the
context of the country*s social and cultural conditions.
We have indicated our general standpoint in regard to
these problems and have defined the scope of the
present work in general terme.We have, in the second chapter, while discussing
the general nature of Intelligence, considered it
helpful to give an historical background to the
current theories about Intelligence. We have traced
the development of the converging notions about
Intelligence up to 1927, the date of appearance of
Spearman's work "Abilities of Man" and the enunciation
of his hypothesis of Intelligence in terms of "g".
We have discussed Spearman's "g", indicated our viewpoint and summarised what we consider to be a helpful
and useful guide for those who would construct tests
of Intelligence. Finally we have discussed Performance tests in general, and indicated the general
principles of our Battery of Tests.In the third chapter we have given a detailed
description of the tests constituting our Battery,
and in the case of tests devised by ourselves specially
for this Battery, have explained the way we have
devised these teats. A copy of instructions for ad¬
ministering the Battery and the method of scoring the
Battery have been given.The fourth chapter contains details of the sample
on which the standardisation is based. In this
connection the difficulties of testing in the countryside in India have "been pointed out and the way to
meet them indicated.The fifth chapter contains the description of the
factorial analysis we carried out on the Battery of
tests together with the Stanford-Binet scale (Revised
193? - Scale L)„ Thurstonefs Centroid Method with
orthogonal axes was used. It has been found that the
Battery gives the evaluation of at least two factors -
one of a general nature, most probably of the nature
of "g" and the other a Memory factor. Indicationsof
a third factor of the nature of WKM are also found,
but it is not statistically significant in our analysis.
This and other factors, particularly in connection with
our Picture test, may also be present in the Battery.
It was not possible to indicate or demonstrate these
conclusively in view of the limited nature of our data
suitable for analysis.The sixth chapter contains details of standardisa¬
tion of the Battery under three separate heads,
(a) For Literates with non-weighted raw scores; (b)
For Illiterates with non-weighted raw scores, and (c)
For Literates with weighted scores to give the best
prediction for the general factor found in the analysis
in Chapter V.The Reliability and Validity of the Battery is
discussed in the seventh chapter, which also contains
a comparison of the performance of the Literate and
the Illiterate groups on the Battery. The fundament¬
al problem of test performance under different environ¬
mental conditions has been briefly discussed and the
author*s own view has been given, which is that al¬
though environmental conditions do influence, at times
markedly (as in the ease of our groups) the performance
of the subjects, so that it is not safe to compare
whole groups among themselves on the basis of such
tests, it nevertheless stands that within a group the
test performance of an individual is a correct guide
to the relative position in intelligence of the
individual within his group. This is markedly borne
out by two evidences in our investigation. We found
that although the means of the two groups were different,
the dispersions, i.e. the standard deviations were
practically the same, so that there were equally all
varieties of comparative performance in each group.
Also, the I.Qs. of the Illiterate group as determined
by our Battery are remarkably in agreement with the
general opinion of the intelligence of individual boys
as held by those who know them intimately. Environ¬
ment and heredity both, it would thus appear, have a
share, but within the same environment, heredity is
predominant in determining individual traits.Lastly, we have given the results of sociological,
educational and clinical value, in the case of both
the Literate and the Illiterate groups, as obtained by
the use of our Battery of Performance tests.In conclusion we have to point out that the
Battery may be used with advantage in the case of
Literates to give an evaluation of the general intelligence of boys between the ages of 11 to 16 years, and
also to predict an ability, mostly of a practical
nature which is in contrast with the verbal intelligence as measured by most verbal tests of intelligence.
This should be helpful in guidance work in schools
and elsewhere.The Battery may be used with confidence to assess
also the intelligence of illiterate boys between the
ages of 11 to 16 years with the help of norms we have
provided. In the case of Illiterates, the present
investigation opens up a number of points, two of the
more important of which, as they appear to us, are the
investigation of the growth curve for Intelligence
from 15 years up to, say, SO years, and the discovery,
if possible, of tests (understood in the most general
terms) which would reduce the gulf between their
performance and those of the Literates
Quantum correlations and least disturbing local measurements
We examine the evaluation of the minimum information loss due to an unread
local measurement in mixed states of bipartite systems, for a general entropic
form. Such quantity provides a measure of quantum correlations, reducing for
pure states to the generalized entanglement entropy, while in the case of mixed
states it vanishes just for classically correlated states with respect to the
measured system, as the quantum discord. General stationary conditions are
provided, together with their explicit form for general two-qubit states.
Closed expressions for the minimum information loss as measured by quadratic
and cubic entropies are also derived for general states of two-qubit systems.
As application, we analyze the case of states with maximally mixed marginals,
where a general evaluation is provided, as well as X states and the mixture of
two aligned states.Comment: 10 pages, 3 figure
Determinants of maternal care in a region of South India
A cross-sectional survey was conducted during 1993 in urban and rural areas of Karnataka State, India. The survey included 3595 currently married women aged under 35, who had at least one child under five. Nine out of ten women had at least one antenatal consultation during their most recent fertile pregnancies. Most consultations were with doctors and there was minimal use of the services provided by paramedical staff of the primary health care system. Of all respondents, 38 per cent (57% urban and 29% rural) delivered in a hospital, and a majority of institutional deliveries were in private hospitals. Surgical interventions were made in more than one-third of hospital deliveries. There was a marked imbalance between antenatal and postnatal care as fewer than one-fifth of the mothers had a postnatal checkup. The educational level, economic status and religion of the mother are significant predictors of use of maternal health services. The relationship of problems during pregnancy and delivery with subsequent health-related behaviour is also examined
Accelerating the commercialization of home-grown genetically engineered crops
Transgenic crops offer the state-of-the-art, and yet simple-to-use technologies for sustainable enhancement
of agricultural productivity. During the last 20 years, several research groups in India have developed capabilities in
genetic engineering of crop plant species and some of them have isolated promising genes and promoters, with potential
for commercialization. However, isolated growth of researchers, limited R&D infrastructure and knowledge base
available in the seed industry, and the regulatory processes involved in the release of transgenic cultivars pose serious
challenges to accelerating the conversion of such leads into field crops. There is an urgent need to evolve efficient
managerial approaches for developing and advancing genetically engineered cultivars into Indian agriculture. This article
emphasizes the need to identify the most promising transgenics and genes available in the country, evaluate the related
intellectual property issues and provide unstinted support to accelerate the process of their commercialization. An
approach that would synergize public-public and public-private partnerships needs to be evolved. Initially, it may be
driven by public sector through crop- and trait-specific consortia, comprising researchers and the seed industry. A few
of such examples should be taken to the stage of clearance by GEAC for unregulated release of indigenously developed
transgenic cultivars. These would then serve as role models and catalyse the formation of need-based teams and lasting
partnerships, needed to usher Indian agriculture into a globally competitive phase of sustainable productivity
Entropic uncertainty relations and entanglement
We discuss the relationship between entropic uncertainty relations and
entanglement. We present two methods for deriving separability criteria in
terms of entropic uncertainty relations. Especially we show how any entropic
uncertainty relation on one part of the system results in a separability
condition on the composite system. We investigate the resulting criteria using
the Tsallis entropy for two and three qubits.Comment: 8 pages, 3 figures, v2: small change
A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction
The XA region of the Cygnus Loop is a complex zone of radiative and
nonradiative shocks interacting with interstellar clouds. We combine five far
ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT),
a grid of 24 IUE spectra and a high-resolution longslit Halpha spectrum to
study the spatial emission line variations across the region. These spectral
data are placed in context using ground-based, optical emission line images of
the region and a far-UV image obtained by the Ultraviolet Imaging Telescope
(UIT). The presence of high-ionization ions (OVI, NV, CIV) indicates a shock
velocity near 170 km/s while other diagnostics indicate v_shock=140 km/s. It is
likely that a large range of shock velocities may exist at a spatial scale
smaller than we are able to resolve. By comparing CIV 1550, CIII 977 and CIII]
1909, we explore resonance scattering across the region. We find that a
significant column depth is present at all positions, including those not near
bright optical/UV filaments. Analysis of the OVI doublet ratio suggests an
average optical depth of about unity in that ion while flux measurements of
[SiVIII] 1443 suggest a hot component in the region at just below 10^6K. Given
the brightness of the OVI emission and the age of the interaction, we rule out
the mixing layer interpretation of the UV emission. Furthermore, we formulate a
picture of the XA region as the encounter of the blast wave with a finger of
dense gas protruding inward from the pre-SN cavity.Comment: 21 pages, 9 figures, accepted by the Astronomical Journal, July 2001
Full resolution figures available at http://fuse.pha.jhu.edu/~danforth/xa
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