6,160 research outputs found
Theory of size-dependent resonance Raman intensities in InP nanocrystals
The resonance Raman spectrum of InP nanocrystals is characterized by features ascribable to both longitudinal (LO) and transverse (TO) optical modes. The intensity ratio of these modes exhibits a strong size dependence. To calculate the size dependence of the LO and TO Raman cross sections, we combine existing models of Raman scattering, the size dependence of electronic and vibrational structure, and electron vibration coupling in solids. For nanocrystals with a radius >10 Ã…, both the LO and TO coupling strengths increase with increasing radius. This, together with an experimentally observed increase in the electronic dephasing rate with decreasing size, allows us to account for the observed ratio of LO/TO Raman intensities
Detection of antibiotics and antibiotic resistance genes in manures from different pig producing systems and in biogas plants
Predictors of emergency department attendance following NHS 111 calls for children and young people: analysis of linked data
Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons
The conventional Wien filter is a device with orthogonal static magnetic and
electric fields, often used for velocity separation of charged particles. Here
we describe the electromagnetic design calculations for a novel waveguide RF
Wien filter that will be employed to solely manipulate the spins of protons or
deuterons at frequencies of about 0.1 to 2 MHz at the COoler SYnchrotron COSY
at J\"ulich. The device will be used in a future experiment that aims at
measuring the proton and deuteron electric dipole moments, which are expected
to be very small. Their determination, however, would have a huge impact on our
understanding of the universe.Comment: 10 pages, 10 figures, 4 table
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Reference-based analysis of lung single-cell sequencing reveals a transitional profibrotic macrophage.
Tissue fibrosis is a major cause of mortality that results from the deposition of matrix proteins by an activated mesenchyme. Macrophages accumulate in fibrosis, but the role of specific subgroups in supporting fibrogenesis has not been investigated in vivo. Here, we used single-cell RNA sequencing (scRNA-seq) to characterize the heterogeneity of macrophages in bleomycin-induced lung fibrosis in mice. A novel computational framework for the annotation of scRNA-seq by reference to bulk transcriptomes (SingleR) enabled the subclustering of macrophages and revealed a disease-associated subgroup with a transitional gene expression profile intermediate between monocyte-derived and alveolar macrophages. These CX3CR1+SiglecF+ transitional macrophages localized to the fibrotic niche and had a profibrotic effect in vivo. Human orthologs of genes expressed by the transitional macrophages were upregulated in samples from patients with idiopathic pulmonary fibrosis. Thus, we have identified a pathological subgroup of transitional macrophages that are required for the fibrotic response to injury
Digital pulse-shape discrimination of fast neutrons and gamma rays
Discrimination of the detection of fast neutrons and gamma rays in a liquid
scintillator detector has been investigated using digital pulse-processing
techniques. An experimental setup with a 252Cf source, a BC-501 liquid
scintillator detector, and a BaF2 detector was used to collect waveforms with a
100 Ms/s, 14 bit sampling ADC. Three identical ADC's were combined to increase
the sampling frequency to 300 Ms/s. Four different digital pulse-shape analysis
algorithms were developed and compared to each other and to data obtained with
an analogue neutron-gamma discrimination unit. Two of the digital algorithms
were based on the charge comparison method, while the analogue unit and the
other two digital algorithms were based on the zero-crossover method. Two
different figure-of-merit parameters, which quantify the neutron-gamma
discrimination properties, were evaluated for all four digital algorithms and
for the analogue data set. All of the digital algorithms gave similar or better
figure-of-merit values than what was obtained with the analogue setup. A
detailed study of the discrimination properties as a function of sampling
frequency and bit resolution of the ADC was performed. It was shown that a
sampling ADC with a bit resolution of 12 bits and a sampling frequency of 100
Ms/s is adequate for achieving an optimal neutron-gamma discrimination for
pulses having a dynamic range for deposited neutron energies of 0.3-12 MeV. An
investigation of the influence of the sampling frequency on the time resolution
was made. A FWHM of 1.7 ns was obtained at 100 Ms/s.Comment: 26 pages, 14 figures, submitted to Nuclear Instruments and Methods in
Physics Research
Factors affecting public access defibrillator placement decisions in the United Kingdom: A survey study
AIM: This study aimed to understand current community PAD placement strategies and identify factors which influence PAD placement decision-making in the United Kingdom (UK). METHODS: Individuals, groups and organisations involved in PAD placement in the UK were invited to participate in an online survey collecting demographic information, facilitators and barriers to community PAD placement and information used to decide where a PAD is installed in their experiences. Survey responses were analysed through descriptive statistical analysis and thematic analysis. RESULTS: There were 106 included responses. Distance from another PAD (66%) and availability of a power source (63%) were most frequently used when respondents are deciding where best to install a PAD and historical occurrence of cardiac arrest (29%) was used the least. Three main themes were identified influencing PAD placement: (i) the relationship between the community and PADs emphasising community engagement to create buy-in; (ii) practical barriers and facilitators to PAD placement including securing consent, powering the cabinet, accessibility, security, funding, and guardianship; and (iii) ‘risk assessment’ methods to estimate the need for PADs including areas of high footfall, population density and type, areas experiencing health inequalities, areas with delayed ambulance response and current PAD provision. CONCLUSION: Decision-makers want to install PADs in locations that maximise impact and benefit to the community, but this can be constrained by numerous social and infrastructural factors. The best location to install a PAD depends on local context; work is required to determine how to overcome barriers to optimal community PAD placement
A review on the genetic resources, domestication and breeding history of spinach (Spinacia oleracea L.)
This paper addresses the genetic resources, domestication and breeding history of spinach as a comprehensive review of these crop aspects is currently unavailable. It is shown that the availability of genetic resources of wild relatives belonging to the primary gene pool is currently very limited, which hampers breeding and research activities. Therefore, new collecting expeditions are clearly warranted. The domestication of spinach is discussed on the basis of its presumed migration routes and the traits that were probably involved in the domestication syndrome. Spinach is thought to have domesticated in former Persia. Migration then occurred eastwards to China and westwards to Europe, but additional genetic data are needed to reveal the most likely migration routes. Morphological changes in pistillate flowers and loss of dormancy are identified as the main traits involved in the domestication syndrome of spinach. To a large extent we could re-construct the relationships between spinach cultivars that were developed until the 1950s, but this appeared difficult for the more recent cultivars due to intellectual property protection by breeding companies. Resistance against downy mildew has been the main breeding target in spinach. The introgression of NBS-LRR resistance genes from wild relatives is the major strategy to develop downy mildew resistant cultivars. However, the use of loss-of-function alleles of susceptibility genes may provide a more durable strategy to develop resistant cultivars. So far, abiotic resistance and quality traits have received minor attention in spinach research and breeding. This is expected to change considering the potential effects of climate change on these traits
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