225 research outputs found
Qualitative research within trials: developing a standard operating procedure for a clinical trials unit
<p>BACKGROUND: Qualitative research methods are increasingly used within clinical trials to address broader research questions than can be addressed by quantitative methods alone. These methods enable health professionals, service users, and other stakeholders to contribute their views and experiences to evaluation of healthcare treatments, interventions, or policies, and influence the design of trials. Qualitative data often contribute information that is better able to reform policy or influence design.</p>
<p>METHODS: Health services researchers, including trialists, clinicians, and qualitative researchers, worked collaboratively to develop a comprehensive portfolio of standard operating procedures (SOPs) for the West Wales Organisation for Rigorous Trials in Health (WWORTH), a clinical trials unit (CTU) at Swansea University, which has recently achieved registration with the UK Clinical Research Collaboration (UKCRC). Although the UKCRC requires a total of 25 SOPs from registered CTUs, WWORTH chose to add an additional qualitative-methods SOP (QM-SOP).</p>
<p>RESULTS: The qualitative methods SOP (QM-SOP) defines good practice in designing and implementing qualitative components of trials, while allowing flexibility of approach and method. Its basic principles are that: qualitative researchers should be contributors from the start of trials with qualitative potential; the qualitative component should have clear aims; and the main study publication should report on the qualitative component.</p>
<p>CONCLUSIONS: We recommend that CTUs consider developing a QM-SOP to enhance the conduct of quantitative trials by adding qualitative data and analysis. We judge that this improves the value of quantitative trials, and contributes to the future development of multi-method trials.</p>
The role of venture capitalists in the regional innovation ecosystem : a comparison of networking patterns between private and publicly backed venture capital funds
This paper empirically examines the development of social networks among venture capitalists and other professionals of the regional innovation ecosystem. Using an online survey of venture capitalists, the article considers their networking behaviour, focusing particularly on the distinction between those employed by private and those employed by publicly backed venture capital funds, and on the composition and spatial search of their networks. It investigates whether the frequency of interaction between venture capitalists and other members of the innovation ecosystem is associated with the nature of the venture capital funds. The paper provides the first detailed investigation of the relationship between different types of venture capitalists and other players of the innovation ecosystem such as universities incubators, research institutes, and business support organisations. The results show that there are distinctive differences within the two seemingly similar professional groups (private and public venture capitalists), and public dependence of the venture capital fund is strongly and significantly associated with higher volumes of interactions. The more publicly dependent a fund is, the more it interacts with other players of the innovation system. This finding has important implications for both academics and practitioners and suggests that publicly backed funds have a wider role to play in mobilising the different players of the regional innovation ecosystem
Spitzer reveals what's behind Orion's Bar
We present Spitzer Space Telescope observations of 11 regions SE of the
Bright Bar in the Orion Nebula, along a radial from the exciting star
theta1OriC, extending from 2.6 to 12.1'. Our Cycle 5 programme obtained deep
spectra with matching IRS short-high (SH) and long-high (LH) aperture grid
patterns. Most previous IR missions observed only the inner few arcmin. Orion
is the benchmark for studies of the ISM particularly for elemental abundances.
Spitzer observations provide a unique perspective on the Ne and S abundances by
virtue of observing the dominant ionization states of Ne (Ne+, Ne++) and S
(S++, S3+) in Orion and H II regions in general. The Ne/H abundance ratio is
especially well determined, with a value of (1.01+/-0.08)E-4. We obtained
corresponding new ground-based spectra at CTIO. These optical data are used to
estimate the electron temperature, electron density, optical extinction, and
the S+/S++ ratio at each of our Spitzer positions. That permits an adjustment
for the total gas-phase S abundance because no S+ line is observed by Spitzer.
The gas-phase S/H abundance ratio is (7.68+/-0.30)E-6. The Ne/S abundance ratio
may be determined even when the weaker hydrogen line, H(7-6) here, is not
measured. The mean value, adjusted for the optical S+/S++ ratio, is Ne/S =
13.0+/-0.6. We derive the electron density versus distance from theta1OriC for
[S III] and [S II]. Both distributions are for the most part decreasing with
increasing distance. A dramatic find is the presence of high-ionization Ne++
all the way to the outer optical boundary ~12' from theta1OriC. This IR result
is robust, whereas the optical evidence from observations of high-ionization
species (e.g. O++) at the outer optical boundary suffers uncertainty because of
scattering of emission from the much brighter inner Huygens Region.Comment: 60 pages, 16 figures, 10 tables. MNRAS accepte
Properties of the ionized gas in HH202. II: Results from echelle spectrophotometry with UVES
We present results of deep echelle spectrophotometry of the brightest knot of
the HH202 in the Orion Nebula --HH202-S-- using the ultraviolet Visual Echelle
Spectrograph (UVES). The high spectral resolution has permitted to separate the
component associated with the ambient gas from that associated with the gas
flow. We derive electron densities and temperatures for both components, as
well as the chemical abundances of several ions and elements from collisionally
excited lines, including the first determinations of Ca^{+} and Cr^{+}
abundances in the Orion Nebula. We also calculate the He^{+}, C^{2+}, O^{+} and
O^{2+} abundances from recombination lines. The difference between the O^{2+}
abundances determined from collisionally excited and recombination lines --the
so-called abundance discrepancy factor-- is 0.35 dex and 0.11 dex for the shock
and nebular components, respectively. Assuming that the abundance discrepancy
is produced by spatial variations in the electron temperature, we derive values
of the temperature fluctuation parameter, t^2, of 0.050 and 0.016, for the
shock and nebular components, respectively. Interestingly, we obtain almost
coincident t^2 values for both components from the analysis of the intensity
ratios of He I lines. We find significant departures from case B predictions in
the Balmer and Paschen flux ratios of lines of high principal quantum number n.
We analyze the ionization structure of HH202-S, finding enough evidence to
conclude that the flow of HH202-S has compressed the ambient gas inside the
nebula trapping the ionization front. We measure a strong increase of the total
abundances of nickel and iron in the shock component, the abundance pattern and
the results of photoionization models for both components are consistent with
the partial destruction of dust after the passage of the shock wave in HH202-S.Comment: 23 pages, 7 figures. Accepted for publication in MNRA
Planetary nebulae in the direction of the Galactic bulge: On nebulae with emission-line central stars
We present a homogeneous set of spectroscopic measurements secured with
4-meter class telescopes for a sample of 90 planetary nebulae (PNe) located in
the direction of the Galactic bulge. We derive their plasma parameters and
chemical abundances. For half of the objects this is done for the first time.
We discuss the accuracy of these data and compare it with other recently
published samples. We analyze various properties of PNe with emission-line
central stars in the Galactic bulge. Investigating the spectra we found that 7
of those PNe are ionized by Wolf-Rayet ([WR]) type stars of the very late (VL)
spectral class [WC 11] and 8 by weak emission-line (WEL) stars. From the
analysis we conclude that the PN central stars of WEL, VL and remaining [WR]
types form three, evolutionary unconnected forms of enhanced mass-loss among
central stars of PNe. [WR] PNe seem to be intrinsically brighter than other
PNe. Overall, we find no statistically significant evidence that the chemical
composition of PNe with emission-line central stars is different from that of
the remaining Galactic bulge PNe.Comment: 19 pages, 23 figures, 16 pages of online material, A&A in pres
The dynamics of entry, exit and profitability: an error correction approach for the retail industry
We develop a two equation error correction model to investigate determinants of and dynamic interaction between changes in profits and number of firms in retailing. An explicit distinction is made between the effects of actual competition among incumbants, new firms competition and potential competition from firms outside the market. Effects of cost, demand and general income changes on profitability are investigated to gain insight in the role of retailing in the cost, demand and wage inflationary processes. The relative importance of profitability, growth and unemployment as determinants of net entry are studied. The model is tested using a panel data set of 36 Dutch shoptypes covering the 1977–1988 period
The ionized gas at the center of IC 10: A possible localized chemical pollution by Wolf-Rayet stars
We present results from integral field spectroscopy with the Potsdam
Multi-Aperture Spectrograph at the 3.5m telescope at Calar Alto Observatory of
the intense star-forming region [HL90] 111 at the center of the starburst
galaxy IC 10. We have obtained maps with a spatial sampling of 1" x 1" = 3.9 pc
x 3.9 pc of different emission lines and analyzed the extinction, physical
conditions, nature of the ionization, and chemical abundances of the ionized
gas, as well determined locally the age of the most recent star-formation
event. By defining several apertures, we study the main integrated properties
of some regions within [HL90] 111. Two contiguous spaxels show an unambiguous
detection of the broad He II 4686 emission line, this feature seems to be
produced by a single WNL star. We also report a probable N and He enrichment in
the precise spaxels where the WR features are detected. The enrichment pattern
is roughly consistent with that expected for the pollution of the ejecta of a
single or a very small number of WR stars. Furthermore, this chemical pollution
is very localized (~2"~7.8 pc) and it should be difficult to detect in
star-forming galaxies beyond the Local Volume. We also discuss the use of the
most-common empirical calibrations to estimate the oxygen abundances of the
ionized gas in nearby galaxies from 2D spectroscopic data. The ionization
degree of the gas plays an important role when applying these empirical
methods, as they tend to give lower oxygen abundances with increasing
ionization degree.Comment: 18 pages, 13 figures, accepted for publication in MNRA
Choline Dehydrogenase Polymorphism rs12676 Is a Functional Variation and Is Associated with Changes in Human Sperm Cell Function
Approximately 15% of couples are affected by infertility and up to half of these cases arise from male factor infertility. Unidentified genetic aberrations such as chromosomal deletions, translocations and single nucleotide polymorphisms (SNPs) may be the underlying cause of many cases of idiopathic male infertility. Deletion of the choline dehydrogenase (Chdh) gene in mice results in decreased male fertility due to diminished sperm motility; sperm from Chdh−/− males have decreased ATP concentrations likely stemming from abnormal sperm mitochondrial morphology and function in these cells. Several SNPs have been identified in the human CHDH gene that may result in altered CHDH enzymatic activity. rs12676 (G233T), a non-synonymous SNP located in the CHDH coding region, is associated with increased susceptibility to dietary choline deficiency and risk of breast cancer. We now report evidence that this SNP is also associated with altered sperm motility patterns and dysmorphic mitochondrial structure in sperm. Sperm produced by men who are GT or TT for rs12676 have 40% and 73% lower ATP concentrations, respectively, in their sperm. rs12676 is associated with decreased CHDH protein in sperm and hepatocytes. A second SNP located in the coding region of IL17BR, rs1025689, is linked to altered sperm motility characteristics and changes in choline metabolite concentrations in sperm
Ionized gas diagnostics from protoplanetary discs in the Orion Nebula and the abundance discrepancy problem
We present results from integral field spectroscopy with PMAS. The observed
field contains: five protoplanetary discs (also known as proplyds), the
high-velocity jet HH 514 and a bowshock. Spatial distribution maps are obtained
for different emission line fluxes, the c(H{\beta}) coefficient, electron
densities and temperatures, ionic abundances of different ions from
collisionally excited lines (CELs), C2+ and O2+ abundances from recombination
lines (RLs) and the abundance discrepancy factor of O2+, ADF(O2+). We find that
collisional de-excitation has a major influence on the line fluxes in the
proplyds. If this is not properly accounted for then physical conditions
deduced from commonly used line ratios will be in error, leading to unreliable
chemical abundances for these objects. We obtain the intrinsic emission of the
proplyds 177-341, 170-337 and 170-334 by a direct subtraction of the background
emission, though the last two present some background contamination due to
their small sizes. A detailed analysis of 177-341 spectra reveals the presence
of high-density gas (3.8\times10^5 cm^-3) in contrast to the typical values
observed in the background gas of the nebula (3800 cm^-3). We also explore how
the background subtraction could be affected by the possible opacity of the
proplyd. We construct a physical model for the proplyd 177-341 finding a good
agreement between the predicted and observed line ratios. Finally, we find that
the use of reliable physical conditions returns an ADF(O2+) about zero for the
intrinsic spectra of 177-341, while the background emission presents the
typical ADF(O2+) observed in the Orion Nebula. We conclude that the presence of
high-density ionized gas is severely affecting the abundances determined from
CELs and, therefore, those from RLs should be considered as a better
approximation to the true abundances.Comment: 22 pages, 11 figures. Accepted for publication in MNRA
M1-78: a nitrogen-rich Galactic compact HII region beyond the Perseus arm
There is considerable controversy surrounding the nature of M1-78, a compact
nebula located beyond the Perseus arm. It was first classified as a planetary
nebula and is nowadays generally considered to be a compact HII region. To
investigate the nature M1-78 further, we present a detailed spectroscopic study
of M1-78 in the optical and near-infrared. M1-78 is a high-density nebula with
substantial physical differences between its two main morphological zones: a
bright arc to the SW and a blob of emission in the NE. Specifically, the blob
in the NE has a higher electron temperature and visual extinction than the SW
arc. The most important result, however, is the confirmation of a nitrogen
enrichment in M1-78. This enrichment is stronger at the location of the NE blob
and is correlated with a defficiency in the O abundance and a (dubious) He
enrichment. Such an abundance pattern is typical of ejecta nebulae around
evolved massive stars such as Wolf-Rayet and Luminous Blue Variable stars. The
spatial variations in the physical conditions and chemical abundances and the
presence of more than one possible ionizing source indicates, however, that
M1-78 is better described as a combination of a compact HII region + ejecta.
Finally, we detect H2 emission that extends over a large (~30 arcsec) area
around the ionized nebula. Analysis of the near-infrared H2 lines indicates
that the excitation mechanism is UV fluorescence.Comment: 14 pages, 8 figures. Accepted for publication in A&
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