1,076 research outputs found
A call to introduce newborn screening for spinal muscular atrophy (SMA) in Scotland
Peer reviewedPublisher PD
IPDâthe Immuno Polymorphism Database
The Immuno Polymorphism Database (IPD), http://www.ebi.ac.uk/ipd/ is a set of specialist databases related to the study of polymorphic genes in the immune system. The IPD project works with specialist groups or nomenclature committees who provide and curate individual sections before they are submitted to IPD for online publication. The IPD project stores all the data in a set of related databases. IPD currently consists of four databases: IPD-KIR, contains the allelic sequences of killer-cell immunoglobulin-like receptors, IPD-MHC, a database of sequences of the major histocompatibility complex of different species; IPD-HPA, alloantigens expressed only on platelets; and IPD-ESTDAB, which provides access to the European Searchable Tumour Cell-Line Database, a cell bank of immunologically characterized melanoma cell lines. The data is currently available online from the website and FTP directory. This article describes the latest updates and additional tools added to the IPD project
Model refinements and experimental testing of highly flexible piezoelectric energy harvesters
This paper addresses limitations to existing analytical models for piezoelectric energy harvesters. The presented model is targeted at predicting behaviours of highly flexible piezoelectric devices (FPEDs) and includes high orders of substrate and piezoelectric material nonlinearity, geometric nonlinearity, and additionally the effects of both self-weight and pre-stress. Validation through experimental testing is provided.
The influence of self-weight on vibratory dynamics becomes important in FPEDs due to both material composition and dimension. The developed model facilitates the simulation of FPED performance mounted at specified angles to the horizontal. In one study, for a FPED of 120 mm in length, the resonant frequency changed by over 30 percent with mounting angle. Consideration of mounting orientation is advised as self-weight increases damping and significantly lowers FPED performance â over a 50 percent reduction in one presented case
The IMGT/HLA database
It is 14 years since the IMGT/HLA database was first released, providing the HLA community with a searchable repository of highly curated HLA sequences. The HLA complex is located within the 6p21.3 region of human chromosome 6 and contains more than 220 genes of diverse function. Of these, 21 genes encode proteins of the immune system that are highly polymorphic. The naming of these HLA genes and alleles and their quality control is the responsibility of the World Health Organization Nomenclature Committee for Factors of the HLA System. Through the work of the HLA Informatics Group and in collaboration with the European Bioinformatics Institute, we are able to provide public access to these data through the website http://www.ebi.ac.uk/imgt/hla/. Regular updates to the website ensure that new and confirmatory sequences are dispersed to the HLA community and the wider research and clinical communities. This article describes the latest updates and additional tools added to the IMGT/HLA project
The Gradients in the 47 Tuc Red Giant Branch Bump and Horizontal Branch are Consistent With a Centrally-Concentrated, Helium-Enriched Second Stellar Generation
We combine ground and space-based photometry of the Galactic globular cluster
47 Tuc to measure four independent lines of evidence for a helium gradient in
the cluster, whereby stars in the cluster outskirts would have a lower initial
helium abundance than stars in and near the cluster core. First and second, we
show that the red giant branch bump (RGBB) stars exhibit gradients in their
number counts and brightness. With increased separation from the cluster
center, they become more numerous relative to the other red giant (RG) stars.
They also become fainter. For our third and fourth lines of evidence, we show
that the horizontal branch (HB) of the cluster becomes both fainter and redder
for sightlines farther from the cluster center. These four results are
respectively detected at the 2.3, 3.6, 7.7 and
4.1 levels. Each of these independent lines of evidence is found to be
significant in the cluster-outskirts; closer in, the data are more compatible
with uniform mixing. Our radial profile is qualitatively consistent with but
quantitatively tighter than previous results based on CN absorption. These
observations are qualitatively consistent with a scenario wherein a second
generation of stars with modestly enhanced helium and CNO abundance formed deep
within the gravitational potential of a cluster of previous generation stars
having more canonical abundances.Comment: 20 pages, 6 figures, 1 table, submitted to The Astrophysical Journa
Combined hydrogen diesel combustion : an experimental investigation into the effects of hydrogen addition on the exhaust gas emissions, particulate matter size distribution and chemical composition
This investigation examines the effects of load, speed, exhaust gas recirculation (EGR) level and hydrogen addition level on the exhaust gas emissions, particulate matter size distribution and chemical composition. The experiments were performed on a 2.0 litre, 4 cylinder, direct injection engine. EGR levels were then varied from 0% to 40%. Hydrogen induction was varied between 0 and 10% vol. of the inlet charge. In the case of using hydrogen and EGR, the hydrogen replaced air. The load was varied from 0 to 5.4 bar BMEP at two engine speeds, 1500 rpm and 2500 rpm. For this investigation the carbon monoxide (CO), total unburnt hydrocarbons (THC), nitrogen oxides (NOX) and the filter smoke number (FSN) were all measured. The in-cylinder pressure was also captured to allow the heat release rate to be calculated and, therefore, the combustion to be analysed. A gravimetric analysis of the particulate matter size distribution was conducted using a nano-MOUDI. Finally, a GC-MS was used to determine the chemical composition of the THC emissions. The experimental data showed that although CO, FSN and THC increase with EGR, NOX emissions decrease. Inversely, CO, FSN and THC emissions decrease with hydrogen, but NOX increases. When hydrogen was introduced the peak cylinder pressure was increased, as was the maximum rate of in-cylinder pressure rise. The position of the peak cylinder pressure was delayed as hydrogen addition increased. This together with the obtained heat release patterns shows an increase in ignition delay, and a higher proportion of premixed combustion. The experimental work showed that the particulate matter size distribution was not dramatically altered by the addition of EGR, but the main peak was slightly shifted towards the nucleation mode with the addition of hydrogen. Hydrogen addition does not appear to have a large effect on the chemical composition of the THC, but does dramatically decrease the emissions.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Combined hydrogen diesel combustion : an experimental investigation into the effects of hydrogen addition on the exhaust gas emissions, particulate matter size distribution and chemical composition
This investigation examines the effects of load, speed, exhaust gas recirculation (EGR) level and hydrogen addition level on the exhaust gas emissions, particulate matter size distribution and chemical composition. The experiments were performed on a 2.0 litre, 4 cylinder, direct injection engine. EGR levels were then varied from 0% to 40%. Hydrogen induction was varied between 0 and 10% vol. of the inlet charge. In the case of using hydrogen and EGR, the hydrogen replaced air. The load was varied from 0 to 5.4 bar BMEP at two engine speeds, 1500 rpm and 2500 rpm. For this investigation the carbon monoxide (CO), total unburnt hydrocarbons (THC), nitrogen oxides (NOX) and the filter smoke number (FSN) were all measured. The in-cylinder pressure was also captured to allow the heat release rate to be calculated and, therefore, the combustion to be analysed. A gravimetric analysis of the particulate matter size distribution was conducted using a nano-MOUDI. Finally, a GC-MS was used to determine the chemical composition of the THC emissions. The experimental data showed that although CO, FSN and THC increase with EGR, NOX emissions decrease. Inversely, CO, FSN and THC emissions decrease with hydrogen, but NOX increases. When hydrogen was introduced the peak cylinder pressure was increased, as was the maximum rate of in-cylinder pressure rise. The position of the peak cylinder pressure was delayed as hydrogen addition increased. This together with the obtained heat release patterns shows an increase in ignition delay, and a higher proportion of premixed combustion. The experimental work showed that the particulate matter size distribution was not dramatically altered by the addition of EGR, but the main peak was slightly shifted towards the nucleation mode with the addition of hydrogen. Hydrogen addition does not appear to have a large effect on the chemical composition of the THC, but does dramatically decrease the emissions.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
The FERRUM project: laboratory-measured transition probabilities for Cr II
Aims: We measure transition probabilities for Cr II transitions from the z
^4H_J, z ^2D_J, y ^4F_J, and y ^4G_J levels in the energy range 63000 to 68000
cm^{-1}. Methods: Radiative lifetimes were measured using time-resolved
laser-induced fluorescence from a laser-produced plasma. In addition, branching
fractions were determined from intensity-calibrated spectra recorded with a UV
Fourier transform spectrometer. The branching fractions and radiative lifetimes
were combined to yield accurate transition probabilities and oscillator
strengths. Results: We present laboratory measured transition probabilities for
145 Cr II lines and radiative lifetimes for 14 Cr II levels. The
laboratory-measured transition probabilities are compared to the values from
semi-empirical calculations and laboratory measurements in the literature.Comment: 13 pages. Accepted for publication in A&
Functional consequences of Palaeozoic reef collapse
Biogenic reefs have been hotspots of biodiversity and evolutionary novelty throughout the Phanerozoic. The largest reef systems in Earthâs history occurred in the Devonian period, but collapsed during the Late Devonian Mass Extinction. However, the consequences for the functional diversity of Palaeozoic reefs have received little attention. Here, we examine changes in the functional diversity of tabulate coral assemblages over a 35 million year period from the middle Devonian to the Carboniferous, straddling the multiphase extinction event to identify the causes and ecological consequences of the extinction for tabulate corals. By examining five key morphological traits, we show a divergent response of taxonomic and functional diversity to the mass extinction: taxonomic richness peaked during the Givetian (~ 388â383 Ma) and coincided with peak reef building, but functional diversity was only moderate because many species had very similar trait combinations. The collapse of taxonomic diversity and reef building in the late Devonian had minimal impact on functional richness of coral assemblages. However, non-random shifts towards species with larger corallites and lower colony integration suggest a shift from photosymbiotic to asymbiotic taxa associated over the study period. Our results suggest that the collapse of the huge Devonian reef systems was correlated with a breakdown of photosymbiosis and extinction of photosymbiotic tabulate coral taxa. Despite the appearance of new tabulate coral species over the next 35 million years, the extinction of taxa with photosymbiotic traits had long-lasting consequences for reef building and, by extension, shallow marine ecosystems in the Palaeozoic
The Lyman-alpha Forest and Heavy Element Systems of GB1759+7539
(abridged) We present observations of the high-redshift QSO GB1759+7539
(z=3.05) obtained with HIRES on the Keck 10m telescope. The spectrum has a
resolution of FWHM = 7 km/s, and a typical signal-to-noise ratio per 2 km/s
pixel of ~25 in the Ly-alpha forest region, and ~60 longward of the Ly-alpha
emission. The observed Ly-alpha forest systems have a mean redshift of z=2.7.
There is marginal evidence of clustering along the line of sight over the
velocity range 100 < v < 250 km/s. The 1-point and 2-point joint probability
distributions of the transmitted flux for the Ly-alpha forest were calculated,
and shown to be very insensitive to the heavy element contamination. We could
find no evidence of Voigt profile departures due to infalling gas, as observed
in the simulated forest spectra. Twelve heavy-element absorption systems were
identified, including damped Lyman-alpha systems at z=2.62 and 2.91. The C, N,
O, Al, Si, P, S, Mg, Fe, and Ni absorption features of these systems were
studied, and the elemental abundances calculated for the weak unsaturated
lines. The systems have metallicities of Z(2.62) ~1/20 Z(solar) and Z(2.91)
\~1/45 Z(solar). Both systems appear to have a low dust content. They show an
over-abundance of alpha-elements relative to Fe-peak elements, and an
under-abundance of odd atomic number elements relative to even. Nitrogen was
observed, and found to be under-abundant relative to oxygen, in line with the
time delay model of primary nitrogen production. C II* was also seen, allowing
us to determine an upper limit to the cosmic microwave background temperature
at z=2.62 of T(CMB)<12.9K.Comment: Added reference, and new S & N abundance determinations for z=2.91
syste
- âŠ