278 research outputs found
Quark-antiquark composite systems: the Bethe-Salpeter equation in the spectral-integration technique
The Bethe-Salpeter equations for the light-quark composite systems, q q-bar,
are written in terms of spectral integrals. For the q q-bar -mesons
characterized by the mass M, spin J and radial quantum number n, the equations
are presented for the following (n,M^2)-trajectories: pi_J, eta_J, a_J, f_J,
rho_J, omega_J, h_J and b_J.Comment: 42 pages, 5 figures, typos correcte
The Political Economy of Myanmar's Transition
This is an Author's Original Manuscript of an article whose final and definitive form, the Version of Record, has been published in the JOURNAL OF CONTEMPORARY ASIA, 07 Feb 2013, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/00472336.2013.764143.Since holding elections in 2010, Myanmar has transitioned from a direct military dictatorship to a formally democratic system and has embarked on a period of rapid economic reform. After two decades of military rule, the pace of change has startled almost everyone and led to a great deal of cautious optimism. To make sense of the transition and assess the case for optimism, this article explores the political economy of Myanmar's dual transition from state socialism to capitalism and from dictatorship to democracy. It analyses changes within Myanmar society from a critical political economy perspective in order to both situate these developments within broader regional trends and to evaluate the country's current trajectory. In particular, the emergence of state-mediated capitalism and politico-business complexes in Myanmar's borderlands are emphasised. These dynamics, which have empowered a narrow oligarchy, are less likely to be undone by the reform process than to fundamentally shape the contours of reform. Consequently, Myanmar's future may not be unlike those of other Southeast Asian states that have experienced similar developmental trajectories
An ultrasensitive reverse transcription polymerase chain reaction assay to detect asymptomatic low-density Plasmodium falciparum and Plasmodium vivax infections in small volume blood samples.
BackgroundHighly sensitive, scalable diagnostic methods are needed to guide malaria elimination interventions. While traditional microscopy and rapid diagnostic tests (RDTs) are suitable for the diagnosis of symptomatic malaria infection, more sensitive tests are needed to screen for low-density, asymptomatic infections that are targeted by interventions aiming to eliminate the entire reservoir of malaria infection in humans.MethodsA reverse transcription polymerase chain reaction (RT- PCR) was developed for multiplexed detection of the 18S ribosomal RNA gene and ribosomal RNA of Plasmodium falciparum and Plasmodium vivax. Simulated field samples stored for 14 days with sample preservation buffer were used to assess the analytical sensitivity and specificity. Additionally, 1750 field samples from Southeastern Myanmar were tested both by RDT and ultrasensitive RT-PCR.ResultsLimits of detection (LoD) were determined under simulated field conditions. When 0.3 mL blood samples were stored for 14 days at 28 °C and 80% humidity, the LoD was less than 16 parasites/mL for P. falciparum and 19.7 copies/µL for P. vivax (using a plasmid surrogate), about 10,000-fold lower than RDTs. Of the 1739 samples successfully evaluated by both ultrasensitive RT-PCR and RDT, only two were RDT positive while 24 were positive for P. falciparum, 108 were positive for P. vivax, and 127 were positive for either P. vivax and/or P. falciparum using ultrasensitive RT-PCR.ConclusionsThis ultrasensitive RT-PCR method is a robust, field-tested screening method that is vastly more sensitive than RDTs. Further optimization may result in a truly scalable tool suitable for widespread surveillance of low-level asymptomatic P. falciparum and P. vivax parasitaemia
Calibrated Sub-Bundles in Non-Compact Manifolds of Special Holonomy
This paper is a continuation of math.DG/0408005. We first construct special
Lagrangian submanifolds of the Ricci-flat Stenzel metric (of holonomy SU(n)) on
the cotangent bundle of S^n by looking at the conormal bundle of appropriate
submanifolds of S^n. We find that the condition for the conormal bundle to be
special Lagrangian is the same as that discovered by Harvey-Lawson for
submanifolds in R^n in their pioneering paper. We also construct calibrated
submanifolds in complete metrics with special holonomy G_2 and Spin(7)
discovered by Bryant and Salamon on the total spaces of appropriate bundles
over self-dual Einstein four manifolds. The submanifolds are constructed as
certain subbundles over immersed surfaces. We show that this construction
requires the surface to be minimal in the associative and Cayley cases, and to
be (properly oriented) real isotropic in the coassociative case. We also make
some remarks about using these constructions as a possible local model for the
intersection of compact calibrated submanifolds in a compact manifold with
special holonomy.Comment: 20 pages; for Revised Version: Minor cosmetic changes, some
paragraphs rewritten for improved clarit
Bound q\bar q Systems in the Framework of the Different Versions of the 3-Dimensional Reductions of the Bethe-Salpeter Equation
Bound q\bar q systems are studied in the framework of different 3-dimensional
relativistic equations derived from the Bethe-Salpeter equation with the
instantaneous kernel in the momentum space. Except the Salpeter equation, all
these equations have a correct one-body limit when one of the constituent quark
masses tends to infinity. The spin structure of the confining qq interaction
potential is taken in the form ,
with . At first stage, the one-gluon-exchange potential is
neglected and the confining potential is taken in the oscillator form. For the
systems (u\bar s), (c\bar u), (c\bar s) and (u\bar u), (s\bar s) a comparative
qualitative analysis of these equations is carried out for different values of
the mixing parameter x and the confining potential strength parameter. We
investigate: 1)the existence/nonexistence of stable solutions of these
equations; 2) the parameter dependence of the general structure of the meson
mass spectum and leptonic decay constants of pseudoscalar and vector mesons. It
is demonstrated that none of the 3-dimensional equations considered in the
present paper does simultaneously describe even general qualitative features of
the whole mass spectrum of q\bar q systems. At the same time, these versions
give an acceptable description of the meson leptonic decay characteristics.Comment: 22 pages, 5 postscript figures, LaTeX-file (revtex.sty
Charmed quark component of the photon wave function
We determine the c-anti-c component of the photon wave function on the basis
of (i) the data on the transitions e+ e- -> J/psi(3096), psi(3686), psi(4040),
psi(4415), (ii) partial widths of the two-photon decays eta_{c0}(2979),
chi_{c0}(3415), chi_{c2}(3556) -> gamma-gamma, and (iii) wave functions of the
charmonium states obtained by solving the Bethe-Salpeter equation for the
c-anti-c system. Using the obtained c-anti-c component of the photon wave
function we calculate the gamma-gamma decay partial widths for radial
excitation 2S state, eta_{c0}(3594) -> gamma-gamma, and 2P states
chi_{c0}(3849), chi_{c2}(3950) -> gamma-gamma.Comment: 20 pages, 8 figure
Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge II.} Charmonia
In the precedent paper of the authors (hep-ph/0510410), the states
were treated in the framework of the spectral integral equation, together with
simultaneous calculations of radiative decays of the considered bottomonia. In
the present paper, such a study is carried out for the charmonium
states. We reconstruct the interaction in the -sector on the basis of
data for the charmonium levels with , , ,
, , and radiative transitions
, , ,
and , ,
. The levels and their wave functions
are calculated for the radial excitations with . Also, we determine the
component of the photon wave function using the annihilation
data: , , , , , and perform the calculations of the partial widths of
the two-photon decays for the states: , ,
, and states:
, , . We discuss the status of the recently observed states
X(3872) and Y(3941): according to our results, the X(3872) can be either
or , while Y(3941) is .Comment: 24 pages, 9 figure
Quark-diquark Systematics of Baryons: Spectral Integral Equations for Systems Composed by Light Quarks
For baryons composed by the light quarks () we write spectral integral
equation using the notion of two diquarks: (i) axial--vector state,
, with the spin and isospin and (ii) scalar one,
, with the spin and isospin . We present spectral
integral equations for the and states taking into
account quark--diquark confinement interaction.Comment: 13 pages, 2 figure
Rhinobatos annandalei, Bengal Guitarfish
The Bengal Guitarfish (Rhinobatos annandalei) is a small (to 95 cm total length) guitarfish that occurs in
the northern Indian Ocean from the United Arab Emirates (UAE) to Bangladesh, including Sri Lanka. The
western boundary of this species distribution is uncertain due to confusion with the Spotted Guitarfish
(R. punctifer). It is demersal on the inner continental shelf at depths of 5–73 m. The species is mainly a
bycatch of a range of industrial and artisanal gears including demersal trawls, longlines, and gillnets. The
meat is consumed locally and traded internationally, and the skins are exported from Bangladesh to
Myanmar to be made into accessories (e.g. handbags). There is a high level of fisheries resource use and
increasing fishing pressure across the range of this species. Severe population reduction is inferred from
actual levels of exploitation, as well as several historical accounts and contemporary datasets from the
UAE, Iran, Pakistan, and India. Landings data of guitarfishes and rays from the UAE, Iran, Pakistan, India,
and Bangladesh indicate landings declines of 69–93% consistent with population reductions of 80% over
the past three generation lengths (27 years). These levels of declines are not species-specific but are
informative for understanding the broader levels of guitarfish decline in the region. It is suspected that
the Bengal Guitarfish has undergone a population reduction of >80% over the past three generation
lengths (27 years) due to actual levels of exploitation, and it is assessed as Critically Endangered A2d
Population Pharmacokinetic Properties of Piperaquine in Falciparum Malaria: An Individual Participant Data Meta-Analysis.
BACKGROUND: Artemisinin-based combination therapies (ACTs) are the mainstay of the current treatment of uncomplicated Plasmodium falciparum malaria, but ACT resistance is spreading across Southeast Asia. Dihydroartemisinin-piperaquine is one of the five ACTs currently recommended by the World Health Organization. Previous studies suggest that young children (<5 y) with malaria are under-dosed. This study utilised a population-based pharmacokinetic approach to optimise the antimalarial treatment regimen for piperaquine. METHODS AND FINDINGS: Published pharmacokinetic studies on piperaquine were identified through a systematic literature review of articles published between 1 January 1960 and 15 February 2013. Individual plasma piperaquine concentration-time data from 11 clinical studies (8,776 samples from 728 individuals) in adults and children with uncomplicated malaria and healthy volunteers were collated and standardised by the WorldWide Antimalarial Resistance Network. Data were pooled and analysed using nonlinear mixed-effects modelling. Piperaquine pharmacokinetics were described successfully by a three-compartment disposition model with flexible absorption. Body weight influenced clearance and volume parameters significantly, resulting in lower piperaquine exposures in small children (<25 kg) compared to larger children and adults (≥25 kg) after administration of the manufacturers' currently recommended dose regimens. Simulated median (interquartile range) day 7 plasma concentration was 29.4 (19.3-44.3) ng/ml in small children compared to 38.1 (25.8-56.3) ng/ml in larger children and adults, with the recommended dose regimen. The final model identified a mean (95% confidence interval) increase of 23.7% (15.8%-32.5%) in piperaquine bioavailability between each piperaquine dose occasion. The model also described an enzyme maturation function in very young children, resulting in 50% maturation at 0.575 (0.413-0.711) y of age. An evidence-based optimised dose regimen was constructed that would provide piperaquine exposures across all ages comparable to the exposure currently seen in a typical adult with standard treatment, without exceeding the concentration range observed with the manufacturers' recommended regimen. Limited data were available in infants and pregnant women with malaria as well as in healthy individuals. CONCLUSIONS: The derived population pharmacokinetic model was used to develop a revised dose regimen of dihydroartemisinin-piperaquine that is expected to provide equivalent piperaquine exposures safely in all patients, including in small children with malaria. Use of this dose regimen is expected to prolong the useful therapeutic life of dihydroartemisinin-piperaquine by increasing cure rates and thereby slowing resistance development. This work was part of the evidence that informed the World Health Organization technical guidelines development group in the development of the recently published treatment guidelines (2015)
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