841 research outputs found
Educational Attainment, Labour Market Conditions and Unobserved Heterogeneity: The Timing of First and Higher-Order Births in Britain
This paper analyses the effects of women’s education and aggregate unemployment rates on fertility in Britain. We combine micro-data on two cohorts who had different experience of education with macro-data on labour market conditions and examine how these factors impacted on the timing of births in Britain. We present results from hazard models estimated separately for each of two cohorts. The models analyse the timing of the first and second births, focusing on the associations of birth hazards with education level and a time-varying unemployment covariate. In addition we include in the models a range of other factors which may influence fertility behaviour and we utilise a method of controlling for unobserved heterogeneity in a robust fashion
How does genetic risk information for Lynch syndrome translate to risk management behaviours?
Background There is limited research on why some individuals who have undergone predictive genetic testing for Lynch syndrome do not adhere to screening recommendations. This study aimed to explore qualitatively how Lynch syndrome non-carriers and carriers translate genetic risk information and advice to decisions about risk managment behaviours in the Australian healthcare system. Methods Participants of the Australasian Colorectal Cancer Family Registry who had undergone predictive genetic testing for Lynch syndrome were interviewed on their risk management behaviours. Transcripts were analysed thematically using a comparative coding analysis. Results Thirty-three people were interviewed. Of the non-carriers (n = 16), 2 reported having apparently unnecessary colonoscopies, and 6 were unsure about what population-based colorectal cancer screening entails. Of the carriers (n = 17), 2 reported they had not had regular colonoscopies, and spoke about their discomfort with the screening process and a lack of faith in the procedure’s ability to reduce their risk of developing colorectal cancer. Of the female carriers (n = 9), 2 could not recall being informed about the associated risk of gynaecological cancers. Conclusion Non-carriers and female carriers of Lynch syndrome could benefit from further clarity and advice about appropriate risk management options. For those carriers who did not adhere to colonoscopy screening, a lack of faith in both genetic test results and screening were evident. It is essential that consistent advice is offered to both carriers and non-carriers of Lynch syndrome
Simulating shallow morphodynamic flows on evolving topographies
We derive general depth-integrated model equations for overland flows
featuring the evolution of suspended sediment that may be eroded from or
deposited onto the underlying topography ('morphodynamics'). The resulting
equations include geometric corrections that account for large variations in
slope angle. These are often non-negligible for Earth-surface flows and may
consequently be important for simulating natural hazards. We also show how to
adapt existing finite volume schemes for the classical shallow water equations,
to simulate our new equations in a way that preserves uniform steady states and
exactly conserves the combined mass of the flow and bed. Finally, to
demonstrate our formulation, we present computations using simple example model
closures, fed by point flux sources. On initially constant slopes, flows
exhibit different behaviours depending on the grade. Shallow slopes lead to
weakly morphodynamic spreading flows that agree well with analytical similarity
solutions. On more severe slopes, rapid erosion occurs, leading to
self-channelising flows and ultimately a 'super-erosive' state, in which
sediment entrainment and gravitational acceleration perpetually reinforce each
other.Comment: 28 pages, 8 figures, 1 tabl
Dense, Parsec-Scale Clumps near the Great Annihilator
We report on Combined Array for Research in Millimeter-Wave Astronomy (CARMA)
and James Clerk Maxwell Telescope (JCMT) observations toward the Einstein
source 1E 1740.7-2942, a LMXB commonly known as the "Great Annihilator." The
Great Annihilator is known to be near a small, bright molecular cloud on the
sky in a region largely devoid of emission in 12-CO surveys of the Galactic
Center. The region is of interest because it is interior to the dust lanes
which may be the shock zones where atomic gas from HI nuclear disk is converted
into molecular gas. We find that the region is populated with a number of dense
(n ~ 10^5 cm^-3) regions of excited gas with small filling factors, and
estimate that up to 1-3 x 10^5 solar masses of gas can be seen in our maps. The
detection suggests that a significant amount of mass is transported from the
shock zones to the GC star-forming regions in the form of small, dense bundles.Comment: 26 pages, 7 figures, accepted for publication by the Astrophysical
Journal, abstract abridge
Cosmic cookery : making a stereoscopic 3D animated movie.
This paper describes our experience making a short stereoscopic movie visualizing the development of structure in
the universe during the 13.7 billion years from the Big Bang to the present day. Aimed at a general audience for
the Royal Society's 2005 Summer Science Exhibition, the movie illustrates how the latest cosmological theories
based on dark matter and dark energy are capable of producing structures as complex as spiral galaxies and
allows the viewer to directly compare observations from the real universe with theoretical results. 3D is an
inherent feature of the cosmology data sets and stereoscopic visualization provides a natural way to present the
images to the viewer, in addition to allowing researchers to visualize these vast, complex data sets.
The presentation of the movie used passive, linearly polarized projection onto a 2m wide screen but it was
also required to playback on a Sharp RD3D display and in anaglyph projection at venues without dedicated
stereoscopic display equipment. Additionally lenticular prints were made from key images in the movie. We
discuss the following technical challenges during the stereoscopic production process; 1) Controlling the depth
presentation, 2) Editing the stereoscopic sequences, 3) Generating compressed movies in display speci¯c formats.
We conclude that the generation of high quality stereoscopic movie content using desktop tools and equipment
is feasible. This does require careful quality control and manual intervention but we believe these overheads
are worthwhile when presenting inherently 3D data as the result is signi¯cantly increased impact and better
understanding of complex 3D scenes
Visualising single molecules of HIV-1 and miRNA nucleic acids
BackgroundThe scarcity of certain nucleic acid species and the small size of target sequences such as miRNA, impose a significant barrier to subcellular visualization and present a major challenge to cell biologists. Here, we offer a generic and highly sensitive visualization approach (oligo fluorescent in situ hybridization, O-FISH) that can be used to detect such nucleic acids using a single-oligonucleotide probe of 19–26 nucleotides in length.ResultsWe used O-FISH to visualize miR146a in human and avian cells. Furthermore, we reveal the sensitivity of O-FISH detection by using a HIV-1 model system to show that as little as 1–2 copies of nucleic acids can be detected in a single cell. We were able to discern newly synthesized viral cDNA and, moreover, observed that certain HIV RNA sequences are only transiently available for O-FISH detection.ConclusionsTaken together, these results suggest that the O-FISH method can potentially be used for in situ probing of, as few as, 1–2 copies of nucleic acid and, additionally, to visualize small RNA such as miRNA. We further propose that the O-FISH method could be extended to understand viral function by probing newly transcribed viral intermediates; and discern the localisation of nucleic acids of interest. Additionally, interrogating the conformation and structure of a particular nucleic acid in situ might also be possible, based on the accessibility of a target sequence
DTN Implementation and Utilization Options on the International Space Station
This slide presentation reviews the implementation and future uses of Delay/Disruption Tolerant Networking (DTN) for space communication, using the International Space Station as the primary example. The presentation includes: (1) A brief introduction of the current communications architecture of the ISS (2) How current payload operations are handled in the non-DTN environment (3) Making the case to implement DTN into the current payload science operations model (4) Phase I DTN Operations: early implementation with BioServe's CGBA Payload (5) Phase II DTN Operations: Developing the HOSC DTN Gatewa
Plasmodium falciparum: linkage disequilibrium between loci in chromosomes 7 and 5 and chloroquine selective pressure in Northern Nigeria.
In view of the recent discovery (Molecular Cell 6, 861-871) of a (Lys76Thr) codon change in gene pfcrt on chromosome 7 which determines in vitro chloroquine resistance in Plasmodium falciparum, we have re-examined samples taken before treatment in our study in Zaria, Northern Nigeria (Parasitology, 119, 343-348). Drug resistance was present in 5/5 cases where the pfcrt 76Thr codon change was seen (100% positive predictive value). Drug sensitivity was found in 26/28 cases where the change was absent (93% negative predictive value). Allele pfcrt 76Thr showed strong linkage disequilibrium with pfmdr1 Tyr86 on chromosome 5, more complete than that between pfcrt and cg2 alleles situated between recombination cross-over points on chromosome 7. Physical linkage of cg2 with pfcrt may account for linkage disequilibrium between their alleles but in the case of genes pfmdr1 and pfcrt, on different chromosomes, it is likely that this is maintained epistatically through the selective pressure of chloroquine
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Balloon pulmonary angioplasty for inoperable chronic thromboembolic pulmonary hypertension: the UK experience.
OBJECTIVE: Inoperable chronic thromboembolic pulmonary hypertension (CTEPH) managed medically has a poor prognosis. Balloon pulmonary angioplasty (BPA) offers a new treatment for inoperable patients. The national BPA service for the UK opened in October 2015 and we now describe the treatment of our initial patient cohort. METHODS: Thirty consecutive, inoperable, anatomically suitable, symptomatic patients on stable medical therapy for CTEPH were identified and offered BPA. They initially underwent baseline investigations including Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) quality of life (QoL) questionnaire, cardiopulmonary exercise test, 6 min walk distance (6MWD), transthoracic echocardiography, N-terminal probrain natriuretic peptide (NT pro-BNP) and right heart catheterisation. Serial BPA sessions were then performed and after completion, the treatment effect was gauged by comparing the same investigations at 3 months follow-up. RESULTS: A median of 3 (IQR 1-6) BPA sessions per patient resulted in a significant improvement in functional status (WHO functional class ≥3: 24 vs 4, p<0.0001) and QoL (CAMPHOR symptom score: 8.7±5.4 vs 5.6±6.1, p=0.0005) with reductions in pulmonary pressures (mean pulmonary artery pressure: 44.7±11.0 vs 34.4±8.3 mm Hg, p<0.0001) and resistance (pulmonary vascular resistance: 663±281 vs 436±196 dyn.s.cm-5, p<0.0001). Exercise capacity improved (minute ventilation/carbon dioxide production: 55.3±12.2 vs 45.0±7.8, p=0.03 and 6MWD: 366±107 vs 440±94 m, p<0.0001) and there was reduction in right ventricular (RV) stretch (NT pro-BNP: 442 (IQR 168-1607) vs 202 (IQR 105-447) pg/mL, p<0.0001) and dimensions (mid RV diameter: 4.4±1.0 vs 3.8±0.7 cm, p=0.002). There were no deaths or life-threatening complications and the mild-moderate per-procedure complication rate was 10.5%. CONCLUSIONS: BPA is safe and improves the functional status, QoL, pulmonary haemodynamics and RV dimensions of patients with inoperable CTEPH
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