55,708 research outputs found
Tests of Power Corrections for Event Shapes in e+e- Annihilation
A study of perturbative QCD calculations combined with power corrections to
model hadronisation effects is presented. The QCD predictions are fitted to
differential distributions and mean values of event shape observables measured
in e+e- annihilation at centre-of-mass energies from 14 to 189 GeV. We
investigate the event shape observables thrust, heavy jet mass, C-parameter,
total and wide jet broadening and differential 2-jet rate and observe a good
description of the data by the QCD predictions. The strong coupling constant
alpha_S(M_Z) and the free parameter of the power correction calculations
alpha_0(2 GeV) are measured to be alpha_S(M_Z) = 0.1171 +/- 0.0032/0.0020 and
alpha_0(2 GeV) = 0.513 +/- 0.066/0.045. The predicted universality of alpha_0
is confirmed within the uncertainties of the measurements.Comment: 28 pages, LaTeX2e, 21 .eps-files included, accepted by Eur. Phys. J.
Inequalities in maternity care and newborn outcomes: one-year surveillance of births in vulnerable slum communities in Mumbai
Background: Aggregate urban health statistics mask inequalities. We described maternity care in
vulnerable slum communities in Mumbai, and examined differences in care and outcomes between
more and less deprived groups.
Methods: We collected information through a birth surveillance system covering a population of
over 280 000 in 48 vulnerable slum localities. Resident women identified births in their own
localities and mothers and families were interviewed at 6 weeks after delivery. We analysed data
on 5687 births over one year to September 2006. Socioeconomic status was classified using
quartiles of standardized asset scores.
Results: Women in higher socioeconomic quartile groups were less likely to have married and
conceived in their teens (Odds ratio 0.74, 95% confidence interval 0.69â0.79, and 0.82, 0.78â0.87,
respectively). There was a socioeconomic gradient away from public sector maternity care with
increasing socioeconomic status (0.75, 0.70â0.79 for antenatal care and 0.66, 0.61â0.71 for
institutional delivery). Women in the least poor group were five times less likely to deliver at home
(0.17, 0.10â0.27) as women in the poorest group and about four times less likely to deliver in the
public sector (0.27, 0.21â0.35). Rising socioeconomic status was associated with a lower
prevalence of low birth weight (0.91, 0.85â0.97). Stillbirth rates did not vary, but neonatal mortality
rates fell non-significantly as socioeconomic status increased (0.88, 0.71â1.08).
Conclusion: Analyses of this type have usually been applied across the population spectrum from
richest to poorest, and we were struck by the regularly stepped picture of inequalities within the
urban poor, a group that might inadvertently be considered relatively homogeneous. The poorest
slum residents are more dependent upon public sector health care, but the regular progression
towards the private sector raises questions about its quality and regulation. It also underlines the
need for healthcare provision strategies to take account of both sectors
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Finite-size effects in lead scandium tantalate relaxor thin films
Large electromechanical effects in relaxor ferroelectrics are generally attributed to the collective response of an ensemble of correlated, nanometer-sized polar structures induced by chemical and charge disorder. Here, we study finite-size effects on such polar order (i.e., how it evolves when sample dimensions approach the polarization correlation length) in 7-70-nm-thick films of the relaxor ferroelectric PbSc0.5Ta0.5O3. Temperature-dependent polarization studies reveal a linear suppression of the polarization and nonlinearity associated with relaxor order as the film thickness decreases to â30 nm. Below this thickness, however, the suppression rapidly accelerates, and polarization is completely absent by film thicknesses of â7 nm, despite the continued observation of a broad peak in dielectric permittivity and frequency dispersion. Diffuse-scattering measurements reveal the diffuse-scattering symmetry, and analysis suggests the films have a polarization correlation length of â23 nm. Taken together, it is apparent that reduction of sample size and the resulting distribution of polar structures drive suppression and eventual quenching of the electrical response of relaxors, which may be attributed to increasing dipole-dipole and dipole-interface interactions
Real-time reverse transcription polymerase chain reaction development for rapid detection of Tomato brown rugose fruit virus and comparison with other techniques
Background: Tomato brown rugose fruit virus (ToBRFV) is a highly infectious tobamovirus that causes severe disease in tomato (Solanum lycopersicum L.) crops. In Italy, the first ToBRFV outbreak occurred in 2018 in several provinces of the Sicily region. ToBRFV outbreak represents a serious threat for tomato crops in Italy and the Mediterranean Basin. Methods: Molecular and biological characterisation of the Sicilian ToBRFV ToB-SIC01/19 isolate was performed, and a sensitive and specific Real-time RT-PCR TaqMan minor groove binder probe method was developed to detect ToBRFV in infected plants and seeds. Moreover, four different sample preparation procedures (immunocapture, total RNA extraction, direct crude extract and leaf-disk crude extract) were evaluated. Results: The Sicilian isolate ToB-SIC01/19 (6,391 nt) showed a strong sequence identity with the isolates TBRFV-P12-3H and TBRFV-P12-3G from Germany, Tom1-Jo from Jordan and TBRFV-IL from Israel. The ToB-SIC01/19 isolate was successfully transmitted by mechanical inoculations in S. lycopersicum L. and Capsicum annuum L., but no transmission occurred in S. melongena L. The developed real-time RT-PCR, based on the use of a primer set designed on conserved sequences in the open reading frames3, enabled a reliable quantitative detection. This method allowed clear discrimination of ToBRFV from other viruses belonging to the genus Tobamovirus, minimising false-negative results. Using immunocapture and total RNA extraction procedures, the real-time RT-PCR and end-point RT-PCR gave the same comparable results. Using direct crude extracts and leaf-disk crude extracts, the end-point RT-PCR was unable to provide a reliable result. This developed highly specific and sensitive real-time RT-PCR assay will be a particularly valuable tool for early ToBRFV diagnosis, optimising procedures in terms of costs and time
Morphological number-count and redshift distributions to I < 26 from the Hubble Deep Field: Implications for the evolution of Ellipticals, Spirals and Irregulars
We combine the photometric redshift data of Fernandez-Soto et al. (1997) with
the morphological data of Odewahn et al. (1996) for all galaxies with I < 26.0
detected in the Hubble Deep Field. From this combined catalog we generate the
morphological galaxy number-counts and corresponding redshift distributions and
compare these to the predictions of high normalization zero- and passive-
evolution models. From this comparison we conclude the following: (1) E/S0s are
seen in numbers and over a redshift range consistent with zero- or minimal
passive- evolution to I = 24. Beyond this limit fewer E/S0s are observed than
predicted implying a net negative evolutionary process --- luminosity dimming,
disassembly or masking by dust --- at I > 24. (2) Spiral galaxies are present
in numbers consistent with zero- evolution predictions to I = 22. Beyond this
magnitude some net- positive evolution is required. Although the number-counts
are consistent with the passive-evolution predictions to I=26.0 the redshift
distributions favor number AND luminosity evolution. (3) There is no obvious
explanation for the late-type/irregular class and this category requires
further subdivision. While a small fraction of the population lies at low
redshift (i.e. true irregulars), the majority lie at redshifts, 1 < z < 3. At z
> 1.5 mergers are frequent and, taken in conjunction with the absence of normal
spirals at z > 2, the logical inference is that they represent the progenitors
of normal spirals forming via hierarchical merging.Comment: Accepted for publication in ApJ Letters, colour plates available from
http://www.phys.unsw.edu.au/~spd/bib.htm
Public Health England's recovery tools: potential teaching resources?
The file attached to this record is the author's final peer reviewed version.Training to combat chemical and radiation accidents, incidents or attacks is critical for health professionals
due to recent events involving these hazards or their use as unconventional weapons, such as the use of
the nerve agent novichok in Salisbury, UK. Health professionals need to have appropriate knowledge and
skills to effectively respond to future events involving any of these substances, which requires a rapid and
coordinated response from different professionals to protect the environment and minimise the number of
people exposed and reduce morbidity and mortality. However, despite chemical and radiation incidents
becoming increasingly prevalent, literature reviews have shown that there is a lack of teaching of
appropriate competences to face future crises in Europe, particularly amongst clinicians and other health
professionals that would be part of the initial response. Thus, De Montfort University (DMU, UK) in
collaboration with different academics from the University of AlcalĂĄ (Spain) and researchers from Public
Health England (PHE) with comprehensive experience in environmental decontamination and restoration,
have created a short training course for providing undergraduate/postgraduate students with basic skills
to respond to chemical incidents, basic skills that are based on the major competences recently identified
by the European Commission [1]. This novel training has been tested with students from different
backgrounds in various European universities, recording high degrees of acquisition of the various basic
competences that we developed to initially respond to chemical events [2]. To develop the practical part
of this chemical training, we have incorporated the novel guidance and methodology developed by PHE
to successfully tailor a protection and recovery response to any incident involving chemical substances,
which is available in the âUK Recovery Handbook for Chemical Incidentsâ [3] and its web-based tools:
âChemical Recovery Navigation Toolâ (CRNT, [4]) and âChemical Recovery Record Formâ (CRRF, [5]).
These innovative resources aid the user to select effective protection, decontamination and restoration
techniques or strategies from a pool of up-to-date options applicable to different environments according
to the physicochemical properties of the chemical(s) involved and the area affected. The CRNT is
accompanied by the CRRF, which facilitates collection and analysis of the necessary data to inform
decisions, and an e-learning resource named âChemical Recovery: Backgroundâ (CRB, [6]), which could
facilitate the learning of environmental decontamination and restoration. We are currently developing a
short training course to cover minor radiation incidents; this radiation training will follow the same methods
used to develop the chemical training, but with the specific PHE recovery tools to tackle such events,
specifically the âUK Recovery Handbooks for Radiation Incidentsâ [7] and its associated web-based tools
âRadiation Recovery Navigation Toolâ (Rad RNT, [8]), one for each environment: food production systems,
inhabited areas and drinking water supplies. This communication will explore the use of the PHEâs
Recovery Navigation Tools as potential resources to facilitate the acquisition of basic knowledge to tailor
protection and recovery interventions for minor chemical and radiation incidents to protect the public
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Large Polarization and Susceptibilities in Artificial Morphotropic Phase Boundary PbZr1âxTixO3 Superlattices
The ability to produce atomically precise, artificial oxide heterostructures allows for the possibility of producing exotic phases and enhanced susceptibilities not found in parent materials. Typical ferroelectric materials either exhibit large saturation polarization away from a phase boundary or large dielectric susceptibility near a phase boundary. Both large ferroelectric polarization and dielectric permittivity are attained wherein fully epitaxial (PbZr0.8Ti0.2O3)n/(PbZr0.4Ti0.6O3)2n (n = 2, 4, 6, 8, 16 unit cells) superlattices are produced such that the overall film chemistry is at the morphotropic phase boundary, but constitutive layers are not. Long- (n â„ 6) and short-period (n = 2) superlattices reveal large ferroelectric saturation polarization (Ps = 64 ”C cmâ2) and small dielectric permittivity (Δr â 400 at 10 kHz). Intermediate-period (n = 4) superlattices, however, exhibit both large ferroelectric saturation polarization (Ps = 64 ”C cmâ2) and dielectric permittivity (Δr = 776 at 10 kHz). First-order reversal curve analysis reveals the presence of switching distributions for each parent layer and a third, interfacial layer wherein superlattice periodicity modulates the volume fraction of each switching distribution and thus the overall material response. This reveals that deterministic creation of artificial superlattices is an effective pathway for designing materials with enhanced responses to applied bias
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