35,592 research outputs found
Regulation, competition, and liberalization
In many countries throughout the world, regulators are struggling to determine whether and how to introduce competition into regulated industries. This essay examines the complexities involved in the liberalization process. While stressing the importance of case-specific analyses, this essay distinguishes liberalization policies that generally are pro-competitive from corresponding anti-competitive liberalization policies
A survey of thermodynamic properties of the compounds of the elements CHNOPS Progress report, 1 Oct. - 31 Dec. 1966
Thermodynamic properties for compounds of the elements carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfu
The silent burden of anaemia in Tanzania children:a community-based study
Objective was to document the prevalence, age-distribution, and risk factors for anaemia in Tanzanian children less than 5 years old,thereby assisting in the development of effective strategies for controlling anaemia.\ud
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Cluster sampling was used to identify 2417 households at random from four contiguous districts in south-eastern\ud
United Republic of Tanzania in mid-1999. Data on various social and medical parameters were collected and analysed.\ud
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Blood haemoglobin concentrations (Hb) were available for 1979 of the 2131 (93%) children identified and ranged from 1.7 to 18.6 g/dl. Overall, 87% (1722) of children had an Hb <11 g/dl, 39% (775) had an Hb <8 g/dl and 3% (65) had an Hb <5 g/dl. The highest prevalence of anaemia of all three levels was in children aged 6–11 months, of whom 10% (22/226) had an Hb <5 g/dl. However, the prevalence of anaemia was already high in children aged 1–5 months (85% had an Hb <11 g/dl, 42% had an Hb <8 g/dl, and 6% had an Hb <5 g/dl). Anaemia was usually asymptomatic and when symptoms arose they were nonspecific and rarely identified as a serious illness by the care provider. A recent history of treatment with antimalarials and iron\ud
was rare. Compliance with vaccinations delivered through the Expanded Programme of Immunization (EPI) was 82% and was notassociated with risk of anaemia.\ud
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Anaemia is extremely common in south-eastern United Republic of Tanzania, even in very young infants. Further implementation of the Integrated Management of Childhood Illness algorithm should improve the case management of anaemia. However, the asymptomatic nature of most episodes of anaemia highlights the need for preventive strategies. The EPI has good coverage of the target population and it may be an appropriate channel for delivering tools for controlling anaemia and malaria
Cruise report hydro acoustic survey for blue whiting (Micromesistius poutassou) with R.V. Tridens, 17 March - 04 April 2008
This is the report of the Dutch part of the international North East Atlantic hydro acoustic survey for blue whiting. The survey is coordinated by ICES and has been executed annually. The purpose of the survey is to estimate the blue whiting stock of the North East Atlantic. The ICES uses this estimation is as a “tuning index” to assess the North East Atlantic blue whiting stock. The applied method was echo integration. By sailing transects over the survey area, the total acoustic cross-section can be calculated by surface area sampled. Trawling identified species composition of localized schools. The length composition of each species was determined. Blue whiting was examined on age and fecundity from which a split up stock structure was mad
Calibrating the Cepheid Period-Luminosity relation with the VLTI
The VLTI is the ideal instrument for measuring the distances of nearby
Cepheids with the Baade-Wesselink method, allowing an accurate recalibration of
the Cepheid Period-Luminosity relation. The high accuracy required by such
measurement, however, can only be reached taking into account the effects of
limb darkening, and its dependence on the Cepheid pulsations. We present here
our new method to compute phase- and wavelength-dependent limb darkening
profiles, based on hydrodynamic simulation of Classical Cepheid atmospheres.Comment: 3 pages, 2 postscript figures, uses eas.cls LaTeX class file, to
appear in the proc. Eurowinter School "Observing with the VLTI", Feb 3-8
2002, Les Houches (France
Bound states of Dipolar Bosons in One-dimensional Systems
We consider one-dimensional tubes containing bosonic polar molecules. The
long-range dipole-dipole interactions act both within a single tube and between
different tubes. We consider arbitrary values of the externally aligned dipole
moments with respect to the symmetry axis of the tubes. The few-body structures
in this geometry are determined as function of polarization angles and dipole
strength by using both essentially exact stochastic variational methods and the
harmonic approximation. The main focus is on the three, four, and five-body
problems in two or more tubes. Our results indicate that in the weakly-coupled
limit the inter-tube interaction is similar to a zero-range term with a
suitable rescaled strength. This allows us to address the corresponding
many-body physics of the system by constructing a model where bound chains with
one molecule in each tube are the effective degrees of freedom. This model can
be mapped onto one-dimensional Hamiltonians for which exact solutions are
known.Comment: 22 pages, 7 figures, revised versio
Observations Supporting the Role of Magnetoconvection in Energy Supply to the Quiescent Solar Atmosphere
Identifying the two physical mechanisms behind the production and sustenance
of the quiescent solar corona and solar wind poses two of the outstanding
problems in solar physics today. We present analysis of spectroscopic
observations from the Solar and Heliospheric Observatory that are consistent
with a single physical mechanism being responsible for a significant portion of
the heat supplied to the lower solar corona and the initial acceleration of the
solar wind; the ubiquitous action of magnetoconvection-driven reprocessing and
exchange reconnection of the Sun's magnetic field on the supergranular scale.
We deduce that while the net magnetic flux on the scale of a supergranule
controls the injection rate of mass and energy into the transition region
plasma it is the global magnetic topology of the plasma that dictates whether
the released ejecta provides thermal input to the quiet solar corona or becomes
a tributary that feeds the solar wind.Comment: 34 pages, 13 figures - In press Astrophysical Journal (Jan 1 2007
Two-Dimensional Sigma-Hole Systems in Boron Layers: A First-Principles Study on Mg_{1-x}Na_xB_2 and Mg_{1-x}Al_xB_2
We study two-dimensional sigma-hole systems in boron layers by calculating
the electronic structures of Mg_{1-x}Na_xB_2 and Mg_{1-x}Al_xB_2. In
Mg_{1-x}Na_xB_2, it is found that the concentration of sigma holes is
approximately described by (0.8 + 0.8 x) * 10^{22} cm^{-3} and the largest
attainable concentration is about 1.6 * 10^{22} cm^{-3} in NaB_2. In
Mg_{1-x}Al_xB_2, on the other hand, it is found that the concentration of sigma
holes is approximately described by (0.8 - 1.4 x) * 10^{22} cm^{-3} and sigma
holes are disappeared at x of about 0.6. These relations can be used for
experimental studies on the sigma-hole systems in these materials.Comment: 5 pages, 5 figure
charmonium state decay into in QCD models including constituent quark mass corrections
Stimulated by the experimental observation, made by the E760 Collaboration at
Fermilab, of the state of charmonium resonantly formed in
annihilation, we perform a calculation of the decay width for the process. To this end, we employ a phenomenological model which adds
constituent quark mass corrections to the usual massless QCD models for
exclusive processes. For massless models, in fact, the process under
consideration is forbidden by the so-called helicity selection rules, while it
is allowed in our extended model. We find to be
in the range eV. We also compare our results with previous, indirect
estimates, based on QCD multipole expansion models.Comment: 17 pages, REVTeX 3.0, 1 postscript figure included. Revised version,
to be published in Physical Review D. Brief discussion of the role of other
nonperturbative effects and three references added in the introduction;
Comparison with QCD multipole expansion model slightly reformulated; Some
sentences added in the conclusions; Results unchange
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