2,212 research outputs found
Формирование композиционных покрытий никель – бор – азот
The methods of X-ray analysis and electron microscopy have been used to study the structure
of nitrogen-ion implanted electrochemical Ni–B coatings with the boron concentration of 8,14
and 20 at %. The implantation is shown to increase coating microhardness from 5,1-5,9 GPa to
10,8-11,7 GPa.
The hardness increase of coatings is attributed to decrease of nickel boride particle size and
formation of γ-BN
Feasibility study and pilot cluster randomised controlled trial of the GoActive Intervention aiming to promote physical activity among adolescents: outcomes and lessons learnt
Assess the feasibility of implementing the GoActive intervention in secondary schools, to identify improvements, test study procedures, determine preliminary effectiveness to increase moderate-to-vigorous physical activity (MVPA), and inform power calculations to establish programme effectiveness.
Feasibility study (1 school) and pilot CRCT (2 intervention;1 control school(s))
460 participants (46.6% female; 13.2(0.4) years-old).
8-week intervention (2013) involved: classes choosing weekly activities encouraged by Mentors (older adolescents) and in-class peer-leaders. Students gain points for trying activities which are entered into an intra-mural competition.
Planned quantitative (questionnaire) and qualitative (focus groups) process evaluation addressed enjoyment, confidence, participation, suggested improvements. Outcomes were assessed at baseline and follow-up (week 8) in pilot CRCT and included: accelerometer-assessed MVPA; adolescent-reported activity type, wellbeing, peer-support, shyness, sociability. ANCOVA was used to assess preliminary effectiveness as change in MVPA adjusted for baseline.
All Year 9 students in intervention schools were exposed to the intervention; over all schools 77% of eligible students were measured. 71% boys and 74% girls found GoActive ‘fun’; 38% boys and 32% girls said it increased confidence and 64% boys and 59% girls said they would continue with a GoActive activity. Suggested improvements included more Mentorship; improved training; streamlined points recording. Pilot results indicated potential effectiveness ((adjusted mean difference (95%CI)p-value) (MVPA mins) 5.1(1.1,9.2)p=0.014)) and suggest recruitment of 16 schools (2400 adolescents) for a full trial. Compared to control, intervention students reported greater peer support 0.5(0.1,0.9)p=0.03, wellbeing 1.8(0.1, 3.4)p=0.04 but no difference in shyness/sociability. Participation in activity types approached significance (intervention group 2.3(-0.2,4.7)p=0.07 more activity types).
Results suggest feasibility and indicate potential effectiveness of GoActive to increase MVPA and support a fully-powered evaluation of effectiveness and cost-effectiveness. Process evaluation data was used to refine GoActive prior to a full trial.
ISRCTN registry ISRCTN31583496.Funding for this study and the work of all authors was supported, wholly or in part, by the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence (RES-590-28-0002). Funding from the British Heart Foundation, Department of Health, Economic and Social Research Council, Medical Research Council, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. The work of Kirsten Corder, Helen Brown and Esther M F van Sluijs was supported by the Medical Research Council (MC_UU_12015/7)
Spectroscopic Transit Search: a self-calibrating method for detecting planets around bright stars
We search for transiting exoplanets around the star Pictoris using
high resolution spectroscopy and Doppler imaging that removes the need for
standard star observations. These data were obtained on the VLT with UVES
during the course of an observing campaign throughout 2017 that monitored the
Hill sphere transit of the exoplanet Pictoris b. We utilize line
profile tomography as a method for the discovery of transiting exoplanets. By
measuring the exoplanet distortion of the stellar line profile, we remove the
need for reference star measurements. We demonstrate the method with white
noise simulations, and then look at the case of Pictoris, which is a
Scuti pulsator. We describe a method to remove the stellar pulsations
and perform a search for any transiting exoplanets in the resultant data set.
We inject fake planet transits with varying orbital periods and planet radii
into the spectra and determine the recovery fraction. In the photon noise
limited case we can recover planets down to a Neptune radius with an 80%
success rate, using an 8 m telescope with a spectrograph and 20
minutes of observations per night. The pulsations of Pictoris limit our
sensitivity to Jupiter-sized planets, but a pulsation removal algorithm
improves this limit to Saturn-sized planets. We present two planet candidates,
but argue that their signals are most likely caused by other phenomena. We have
demonstrated a method for searching for transiting exoplanets that (i) does not
require ancillary calibration observations, (ii) can work on any star whose
rotational broadening can be resolved with a high spectral dispersion
spectrograph and (iii) provides the lowest limits so far on the radii of
transiting Jupiter-sized exoplanets around Pictoris with orbital
periods from 15 days to 200 days with >50% coverage.Comment: Accepted for publication in A&A, 8 pages, 8 figures. The Github
repository can be found at
https://github.com/lennartvansluijs/Spectroscopic-Transit-Searc
Evidence for weathering and volcanism during the PETM from Arctic Ocean and Peri-Tethys osmium isotope records
Sudden global warming during the Paleocene–Eocene Thermal Maximum (PETM, 55.9 Ma) occurred because of the rapid release of several thousand gigatonnes of isotopically light carbon into the oceans and atmosphere; however, the cause of this release is not well understood. Some studies have linked carbon injection to volcanic activity associated with the North Atlantic Igneous Province (NAIP), while others have emphasised carbon cycle feedbacks associated with orbital forcing. This study presents the osmium isotope compositions of mudrocks that were deposited during the PETM at four locations (one from the Arctic Ocean, and three from the Peri-Tethys). The Os-isotope records all exhibit a shift of similar magnitude towards relatively radiogenic values across the PETM. This observation confirms that there was a transient, global increase in the flux of radiogenic Os from the weathering of continental rocks in response to elevated temperatures at that time. The tectonic effects of NAIP volcanic emplacement near the onset of the PETM is recorded by anomalously radiogenic Os-isotope compositions of PETM-age Arctic Ocean samples, which indicate an interval of hydrographic restriction that can be linked tectonic uplift due to hotspot volcanism in the North Atlantic seaway. The Peri-Tethys data also document a transient, higher flux of unradiogenic osmium into the ocean near the beginning of the PETM, most likely from the weathering of young mafic rocks associated with the NAIP. These observations support the hypothesis that volcanism played a major role in triggering the cascade of environmental changes during the PETM, and highlight the influence of paleogeography on the Os isotope characteristics of marine water masses
The implementation of quality management systems in hospitals: a comparison between three countries
BACKGROUND: Is the implementation of Quality Management (QM) in health care proceeding satisfactorily and can national health care policies influence the implementation process? Policymakers and researchers in a country need to know the answer to this question. Cross country comparisons can reveal whether sufficient progress is being made and how this can be stimulated. The objective of the study was to investigate agreement and disparities in the implementation of QMS between The Netherlands, Hungary and Finland with respect to the evaluation model used and the national policy strategy of the three countries. METHODS: The study has a cross sectional design, based on measurements in 2000. Empirical data about QM-activities in hospitals were gathered by a self-administered questionnaire. The questionnaires were answered by the directors of the hospitals or the quality coordinators. The analyses are based on data from 101 hospitals in the Netherlands, 116 hospitals in Hungary and 59 hospitals in Finland. Outcome measures are the developmental stage of the Quality Management System (QMS), the development within five focal areas, and distinct QM-activities which were listed in the questionnaire. RESULTS: A mean of 22 QM-activities per hospital was found in the Netherlands and Finland versus 20 QM-activities in Hungarian hospitals. Only a small number of hospitals has already implemented a QMS (4% in The Netherlands,0% in Hungary and 3% in Finland). More hospitals in the Netherlands are concentrating on quality documents, whereas Finnish hospitals are concentrating on training in QM and guidelines. Cyclic quality improvement activities have been developed in the three countries, but in most hospitals the results were not used for improvements. All three countries pay hardly any attention to patient participation. CONCLUSION: The study demonstrates that the implementation of QM-activities can be measured at national level and that differences between countries can be assessed. The hypothesis that governmental legislation or financial reimbursement can stimulate the implementation of QM-activities, more than voluntary recommendations, could not be confirmed. However, the results show that specific obligations can stimulate the implementation of QM-activities more than general, framework legislation
Management of slipped capital femoral epiphysis: results of a survey of the members of the European Paediatric Orthopaedic Society
AIM: To determine current practice recommendations for the treatment of slipped capital femoral epiphysis (SCFE) among members of the European Paediatric Orthopaedic Society (EPOS). MATERIALS AND METHODS: A questionnaire with 4 case vignettes of a 12-year-old boy presenting with a stable and unstable SCFE. Each, stable and unstable slips, was of mild (20° epiphyseal-shaft angle) and of severe (60° epiphyseal-shaft angle) degree was sent to all members of EPOS in 2009 in order to ascertain their views on the best management of SCFE. Specifically, respondents were asked about the role of reduction, methods of fixation, prophylactic fixation of the non-affected hip, postoperative management and their view on the anticipated need for secondary surgery. RESULTS: The response rate was 25% (72/287). The participating surgeons' average workload was 76% in paediatric orthopaedics, with mean 16 years of experience. Surgeons were most consistent in their advice for stable slips, where around 90% of the respondents did not recommend a reduction of the slip regardless of severity of slip. Seventy per cent of the respondents recommended the use of only one screw for fixation of a stable slip and for mild unstable slips. For severe unstable slips, 46% of surgeons recommended reduction only by positioning of the hip on the fracture table, 35% by manipulation and 11% advised open reduction. Responders were less consistent in their advice on the anticipated need for secondary osteotomies (in mild slips about 40% and about 60% in severe slips would advise an osteotomy) and on treatment of the contralateral hip (with 32% of surgeons recommending prophylactic fixation of the contralateral hip). CONCLUSION: Within members of EPOS, there is controversy on several aspects of the management of SCFE particularly on aspects of the treatment of unstable SCFE. SIGNIFICANCE: Members of EPOS predominantly use traditional means of treatment for patients with SCFE. In contrast, the more modern treatment concepts, such as open reduction via surgical dislocation, are rarely used
Dementia in Parkinson's Disease Correlates with α-Synuclein Pathology but Not with Cortical Astrogliosis
Dementia is a common feature in Parkinson's disease (PD) and is considered to be the result of limbic and cortical Lewy bodies and/or Alzheimer changes. Astrogliosis may also affect the development of dementia, since it correlates well with declining cognition in Alzheimer patients. Thus, we determined whether cortical astrogliosis occurs in PD, whether it is related to dementia, and whether this is reflected by the presence of glial fibrillary acidic protein (GFAP) and vimentin in cerebrospinal fluid (CSF). We have examined these proteins by immunohistochemistry in the frontal cortex and by Western blot in CSF of cases with PD, PD with dementia (PDD), dementia with Lewy bodies (DLB) and nondemented controls. We were neither able to detect an increase in cortical astrogliosis in PD, PDD, or DLB nor could we observe a correlation between the extent of astrogliosis and the degree of dementia. The levels of GFAP and vimentin in CSF did not correlate to the extent of astrogliosis or dementia. We did confirm the previously identified positive correlation between the presence of cortical Lewy bodies and dementia in PD. In conclusion, we have shown that cortical astrogliosis is not associated with the cognitive decline in Lewy body-related dementia
Cycle training and factors associated with cycling among adolescents in England.
BACKGROUND: Cycling has the potential to encourage physical activity as well as advancing societal goals such as reducing carbon emissions; encouraging cycling is therefore a policy goal in many contexts. We analysed individual level data from the whole of England on factors associated with cycling among adolescents, including cycle training delivered by the age of 11 years in primary schools. METHODS: Data came from the nationally representative Millennium Cohort Study collected when participants were aged 13-15 years (adolescents). We assessed frequency of cycling at least once per week (regular cycling) and used logistic regression to assess how this differed across characteristics including demographic, health and environmental factors, as well as receiving cycle training ('Bikeability') in primary school. RESULTS: We found that 21.0% of adolescents cycled at least once per week. In fully adjusted analyses, this was more common among boys than girls (32.5% vs. 9.4%, p < 0.001), and those in rural areas than urban areas (24.9% vs. 20.3%, p < 0.001). Adolescents in areas with higher prevalence of adult cycle commuting were more likely to cycle regularly (26.1% in high cycling areas vs. 19.3% in low cycling areas, p < 0.001). Participants offered cycle training in primary school were not more likely to cycle regularly as adolescents (21.7% vs. 22.3%, p = 0.528). DISCUSSION: Approximately one in five adolescents in England cycles regularly, although being offered cycle training in primary school was not linked to greater cycling. Many of the factors associated with adolescent cycling are similar to those for adults and adolescents are more likely to cycle in areas with higher levels of adult cycling
Southern ocean warming, sea level and hydrological change during the Paleocene-Eocene thermal maximum
A brief (~150 kyr) period of widespread global average surface warming marks the transition between the Paleocene and Eocene epochs, ~56 million years ago. This so-called "Paleocene-Eocene thermal maximum" (PETM) is associated with the massive injection of <sup>13</sup>C-depleted carbon, reflected in a negative carbon isotope excursion (CIE). Biotic responses include a global abundance peak (acme) of the subtropical dinoflagellate <i>Apectodinium</i>. Here we identify the PETM in a marine sedimentary sequence deposited on the East Tasman Plateau at Ocean Drilling Program (ODP) Site 1172 and show, based on the organic paleothermometer TEX<sub>86</sub>, that southwest Pacific sea surface temperatures increased from ~26 °C to ~33°C during the PETM. Such temperatures before, during and after the PETM are >10 °C warmer than predicted by paleoclimate model simulations for this latitude. In part, this discrepancy may be explained by potential seasonal biases in the TEX<sub>86</sub> proxy in polar oceans. Additionally, the data suggest that not only Arctic, but also Antarctic temperatures may be underestimated in simulations of ancient greenhouse climates by current generation fully coupled climate models. An early influx of abundant <i>Apectodinium</i> confirms that environmental change preceded the CIE on a global scale. Organic dinoflagellate cyst assemblages suggest a local decrease in the amount of river run off reaching the core site during the PETM, possibly in concert with eustatic rise. Moreover, the assemblages suggest changes in seasonality of the regional hydrological system and storm activity. Finally, significant variation in dinoflagellate cyst assemblages during the PETM indicates that southwest Pacific climates varied significantly over time scales of 10<sup>3</sup> – 10<sup>4</sup> years during this event, a finding comparable to similar studies of PETM successions from the New Jersey Shelf
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