2,192 research outputs found
The imperial war museum’s social interpretation project
This report represents the output from research undertaken by University of Salford and MTM
London as part of the joint Digital R&D Fund for Arts and Culture, operated by Nesta, Arts
Council England and the AHRC. University of Salford and MTM London received funding from
the programme to act as researchers on the Social Interpretation (SI) project, which was led by
the Imperial War Museum (IWM) and their technical partners, The Centre for Digital
Humanities, University College London, Knowledge Integration, and Gooii. The project was
carried out between October 2011 and October 2012
Fractional quantum Hall effect in the absence of Landau levels
It has been well-known that topological phenomena with fractional
excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982}
will emerge when electrons move in Landau levels. In this letter, we report the
discovery of the FQHE in the absence of Landau levels in an interacting fermion
model. The non-interacting part of our Hamiltonian is the recently proposed
topologically nontrivial flat band model on the checkerboard lattice
\cite{sun}. In the presence of nearest-neighboring repulsion (), we find
that at 1/3 filling, the Fermi-liquid state is unstable towards FQHE. At 1/5
filling, however, a next-nearest-neighboring repulsion is needed for the
occurrence of the 1/5 FQHE when is not too strong. We demonstrate the
characteristic features of these novel states and determine the phase diagram
correspondingly.Comment: 6 pages and 4 figure
The Supernova Gamma-Ray Burst Connection
The chief distinction between ordinary supernovae and long-soft gamma-ray
bursts (GRBs) is the degree of differential rotation in the inner several solar
masses when a massive star dies, and GRBs are rare mainly because of the
difficulty achieving the necessary high rotation rate. Models that do provide
the necessary angular momentum are discussed, with emphasis on a new single
star model whose rapid rotation leads to complete mixing on the main sequence
and avoids red giant formation. This channel of progenitor evolution also gives
a broader range of masses than previous models, and allows the copious
production of bursts outside of binaries and at high redshifts. However, even
the production of a bare helium core rotating nearly at break up is not, by
itself, a sufficient condition to make a gamma-ray burst. Wolf-Rayet mass loss
must be low, and will be low in regions of low metallicity. This suggests that
bursts at high redshift (low metallicity) will, on the average, be more
energetic, have more time structure, and last longer than bursts nearby. Every
burst consists of three components: a polar jet (~0.1 radian), high energy,
subrelativistic mass ejection (~1 radian), and low velocity equatorial mass
that can fall back after the initial explosion. The relative proportions of
these three components can give a diverse assortment of supernovae and high
energy transients whose properties may vary with redshift.Comment: 10 pages, to appear in AIP Conf. Proc. "Gamma Ray Bursts in the Swift
Era", Eds. S. S. Holt, N. Gehrels, J. Nouse
Effects of the EQUIP quasi-experimental study testing a collaborative quality improvement approach for maternal and newborn health care in Tanzania and Uganda.
BACKGROUND: Quality improvement is a recommended strategy to improve implementation levels for evidence-based essential interventions, but experience of and evidence for its effects in low-resource settings are limited. We hypothesised that a systemic and collaborative quality improvement approach covering district, facility and community levels, supported by report cards generated through continuous household and health facility surveys, could improve the implementation levels and have a measurable population-level impact on coverage and quality of essential services. METHODS: Collaborative quality improvement teams tested self-identified strategies (change ideas) to support the implementation of essential maternal and newborn interventions recommended by the World Health Organization. In Tanzania and Uganda, we used a plausibility design to compare the changes over time in one intervention district with those in a comparison district in each country. Evaluation included indicators of process, coverage and implementation practice analysed with a difference-of-differences and a time-series approach, using data from independent continuous household and health facility surveys from 2011 to 2014. Primary outcomes for both countries were birth in health facilities, breastfeeding within 1 h after birth, oxytocin administration after birth and knowledge of danger signs for mothers and babies. Interpretation of the results considered contextual factors. RESULTS: The intervention was associated with improvements on one of four primary outcomes. We observed a 26-percentage-point increase (95% CI 25-28%) in the proportion of live births where mothers received uterotonics within 1 min after birth in the intervention compared to the comparison district in Tanzania and an 8-percentage-point increase (95% CI 6-9%) in Uganda. The other primary indicators showed no evidence of improvement. In Tanzania, we saw positive changes for two other outcomes reflecting locally identified improvement topics. The intervention was associated with an increase in preparation of clean birth kits for home deliveries (31 percentage points, 95% CI 2-60%) and an increase in health facility supervision by district staff (14 percentage points, 95% CI 0-28%). CONCLUSIONS: The systemic quality improvement approach was associated with improvements of only one of four primary outcomes, as well as two Tanzania-specific secondary outcomes. Reasons for the lack of effects included limited implementation strength as well a relatively short follow-up period in combination with a 1-year recall period for population-based estimates and a limited power of the study to detect changes smaller than 10 percentage points. TRIAL REGISTRATION: Pan African Clinical Trials Registry: PACTR201311000681314
Heavy Flavour Production at Tevatron and Parton Shower Effects
We present hadron-level predictions from the Monte Carlo generator Cascade
and numerical calculations of charm and beauty production at the Fermilab
Tevatron within the framework of the -factorization QCD approach. Our
consideration is based on the CCFM-evolved unintegrated gluon densities in a
proton. The performed analysis covers the total and differential cross sections
of open charm and beauty quarks, and mesons (or rather muons from their
semileptonic decays) and the total and differential cross sections of di-jet hadroproduction. We study the theoretical uncertainties of our
calculations and investigate the effects coming from parton showers in initial
and final states. Our predictions are compared with the recent experimental
data taken by the D0 and CDF collaborations. Special attention is put on the
specific angular correlations between the final-state particles. We demonstrate
that the final state parton shower plays a crucial role in the description of
such observables. The decorrelated part of angular separations can be fully
described, if the process is included.Comment: Fig 8,9 10 replaced, small corrections in text A discussion of the
delta phi results is adde
A new cell primo-culture method for freshwater benthic diatom communities
A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation
from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were tested in step 3:
cell culture medium (Chu No 10 vs Freshwater “WC” medium modified), cell culture vessel, and time of culture. The results showed that using Chu No 10 medium in an Erlenmeyer flask for cell culture was the optimal method,
producing enough biomass for ecotoxicological tests as well as minimising development of other microorganisms. After 96 h of culture, communities differed from the original communities sampled in the two rivers studied.
Species tolerant of eutrophic or saprobic conditions were favoured during culture. This method of diatom community culture affords the opportunity to assess, in vitro, the effects of different chemicals or effluents (water samples andindustrial effluents) on diatom communities, as well as on diatom cells, from a wide range of perspectives
Comparison of the application of low concentration and 80% phenol solution in pilonidal sinus disease
Objectives Many conservative methods have been applied in the treatment of pilonidal sinus disease (PSD). The most commonly used conservative treatment is 80% phenol solution. Our observations demonstrated that 80% phenol solution caused much destruction in the sacrococcygeal region. Design In this study low concentrations of phenol were used with the aim of reducing the unwanted side-effects of high-concentration phenol without reducing the therapeutic effects. Participants We treated 112 patients (18 women, 94 men) with PSD using phenol solution. Patients were divided into two groups: Group A was treated with a 40% solution of phenol solution, and Group B was treated with an 80% solution of phenol solution. Setting All patients were treated on an outpatient basis. One mL of low (40%) or high (80%) concentration phenol solution was injected into the main sinus orifice. During the check it was observed and noted whether there was skin necrosis, fatty tissue necrosis or abscesses. Main outcome measures The mean age was 27.4 years (6–44). The median length of symptoms was seven months (0.5–132). In the 2.8 years (1–6) of mean follow-up period, the disease recurred in 13 (11.6%) patients. Results This treatment procedure was well-tolerated by all the patients except for those who had unwanted results. No patients in group A had skin necrosis, and only one had abscesses. In group B two patients had abscesses, and three had skin necrosis. Fatty tissue necrosis was seen in one patient in Group A and in five patients in Group B. Recurrence rates were four (7.4%) cases in Group A and nine (15.5%) cases in Group B. Conclusions It is possible to treat patients in a shorter time with a considerably smaller loss of working time, since the destruction of peripilonidal adipose tissue and skin is less. Therefore, the use of low-concentration phenol solution is an option to be considered in the treatment of PSD.PubMe
Discovery of the peculiar supernova 1998bw in the error box of GRB980425
The discovery of X-ray, optical and radio afterglows of gamma-ray bursts
(GRBs) and the measurements of the distances to some of them have established
that these events come from Gpc distances and are the most powerful photon
emitters known in the Universe, with peak luminosities up to 10^52 erg/s. We
here report the discovery of an optical transient, in the BeppoSAX Wide Field
Camera error box of GRB980425, which occurred within about a day of the
gamma-ray burst. Its optical light curve, spectrum and location in a spiral arm
of the galaxy ESO 184-G82, at a redshift z = 0.0085, show that the transient is
a very luminous type Ic supernova, SN1998bw. The peculiar nature of SN1998bw is
emphasized by its extraordinary radio properties which require that the radio
emitter expand at relativistical speed. Since SN1998bw is very different from
all previously observed afterglows of GRBs, our discovery raises the
possibility that very different mechanisms may give rise to GRBs, which differ
little in their gamma-ray properties.Comment: Under press embargo at Nature (submitted June 10, 1998
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