Analytical study of hydrogen turbopump cycles for advanced nuclear rockets Progress report, Sep. 15, 1964 - Sep. 15, 1965

Hydrogen turbopump cycles for obtaining high engine inlet pressures in advanced nuclear rockets, and data on gaseous nuclear reactors and heavy gas containmen

Simultaneous determination of wave speed and arrival time of reflected waves using the pressure-velocity loop

This is the post print version of the article. The official published version can be found at the link below.In a previous paper we demonstrated that the linear portion of the pressure–velocity loop (PU-loop) corresponding to early systole could be used to calculate the local wave speed. In this paper we extend this work to show that determination of the time at which the PU-loop first deviates from linearity provides a convenient way to determine the arrival time of reflected waves (Tr). We also present a new technique using the PU-loop that allows for the determination of wave speed and Tr simultaneously. We measured pressure and flow in elastic tubes of different diameters, where a strong reflection site existed at known distances away form the measurement site. We also measured pressure and flow in the ascending aorta of 11 anaesthetised dogs where a strong reflection site was produced through total arterial occlusion at four different sites. Wave speed was determined from the initial slope of the PU-loop and Tr was determined using a new algorithm that detects the sampling point at which the initial linear part of the PU-loop deviates from linearity. The results of the new technique for detecting Tr were comparable to those determined using the foot-to-foot and wave intensity analysis methods. In elastic tubes Tr detected using the new algorithm was almost identical to that detected using wave intensity analysis and foot-to-foot methods with a maximum difference of 2%. Tr detected using the PU-loop in vivo highly correlated with that detected using wave intensity analysis (r 2 = 0.83, P < 0.001). We conclude that the new technique described in this paper offers a convenient and objective method for detecting Tr, and allows for the dynamic determination of wave speed and Tr, simultaneously

Prevention of falls and fractures in old people by administration of calcium and vitamin d. randomized clinical trial

<p>Abstract</p> <p>Background</p> <p>There are many studies that associate vitamin D serum levels in older persons with muscle strength, physical performance and risk of fractures and falls. However, current evidence is insufficient to make a general recommendation for administrating calcium and vitamin D to older persons. The objective of this study is to determine the effectiveness of calcium and vitamin D supplementation in improving musculoskeletal function and decreasing the number of falls in person aged over 65 years.</p> <p>Methods/Design</p> <p>Phase III, randomized, double blind, placebo-controlled trial to evaluate the efficacy of already marketed drugs in a new indication. It will be performed at Primary Care doctor visits at several Healthcare Centers in different Spanish Health Areas. A total of 704 non-institutionalized subjects aged 65 years or older will be studied (sample size calculated for a statistical power of 80%, alpha error 0.05, annual incidence of falls 30% and expected reduction of 30% to 20% and expected loss to follow up of 20%). The test drug containing 800 IU of vitamin D and 1000 mg of calcium will be administered daily. The control group will receive a placebo. The subjects will be followed up over two years. The primary variable will be the incidence of spontaneous falls. The secondary variables will include: consequences of the falls (fractures, need for hospitalization), change in calcidiol plasma levels and other analytical determinations (transaminases, PTH, calcium/phosphorous, albumin, creatinine, etc.), change in bone mass by densitometry, change in muscle strength in the dominant hand and change in musculoskeletal strength, risk factors for falls, treatment compliance, adverse effects and socio-demographic data.</p> <p>Discussion</p> <p>The following principles have been considered in the development of this Project: the product data are sufficient to ensure that the risks assumed by the study participants are acceptable, the study objectives will probably provide further knowledge on the problem studied and the available information justifies the performance of the study and its possible risk for the participants.</p> <p>If calcium and vitamin D supplementation is effective in the prevention of falls and fractures in the elderly population, a recommendation may be issued with the aim of preventing some of the consequences of falls that affect quality of life and the ensuing personal, health and social costs.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01452243">NCT01452243</a></p> <p>Clinical trial authorized by the Spanish Medicines Agency: EudraCT number 2006-001643-63.</p

Falls Assessment Clinical Trial (FACT): design, interventions, recruitment strategies and participant characteristics

<p>Abstract</p> <p>Background</p> <p>Guidelines recommend multifactorial intervention programmes to prevent falls in older adults but there are few randomised controlled trials in a real life health care setting. We describe the rationale, intervention, study design, recruitment strategies and baseline characteristics of participants in a randomised controlled trial of a multifactorial falls prevention programme in primary health care.</p> <p>Methods</p> <p>Participants are patients from 19 primary care practices in Hutt Valley, New Zealand aged 75 years and over who have fallen in the past year and live independently. Two recruitment strategies were used – waiting room screening and practice mail-out. Intervention participants receive a community based nurse assessment of falls and fracture risk factors, home hazards, referral to appropriate community interventions, and strength and balance exercise programme. Control participants receive usual care and social visits. Outcome measures include number of falls and injuries over 12 months, balance, strength, falls efficacy, activities of daily living, quality of life, and physical activity levels.</p> <p>Results</p> <p>312 participants were recruited (69% women). Of those who had fallen, 58% of people screened in the practice waiting rooms and 40% when screened by practice letter were willing to participate. Characteristics of participants recruited using the two methods are similar (p > 0.05). Mean age of all participants was 81 years (SD 5). On average participants have 7 medical conditions, take 5.5 medications (29% on psychotropics) with a median of 2 falls (interquartile range 1, 3) in the previous year.</p> <p>Conclusion</p> <p>The two recruitment strategies and the community based intervention delivery were feasible and successful, identifying a high risk group with multiple falls. Recruitment in the waiting room gave higher response rates but was less efficient than practice mail-out. Testing the effectiveness of an evidence based intervention in a 'real life' setting is important.</p> <p>Trial registration</p> <p>Australian Clinical Trials Register ID 12605000054617.</p

The impact of quality management systems on construction performance in the North West of England

As the total construction output in the North West of England (NWE) is forecast to rise by an average of 2.5% over the next five years. It is imperative for organizations in the region to improve their overall construction performance, particularly if they are to hit the targets presented by UK Government in the construction 2025 report. Despite the known benefits of quality management systems (QMS) its implementation in relation to construction performance is very limited, particularly in the UK. Therefore, the purpose of this paper is to examine whether QMS can affect construction performance in the NWE. A pragmatic mixed method approach of sequential explanatory strategy was adopted to conduct this research. This initially involved a quantitative approach of questionnaire surveys to gain opinions and views of a representative sample of industry professionals based in the NWE. The quantitative results were analyzed to discover relationships in the data and further formulate the questions for the qualitative interviews. Three interviews with leading industry professionals were then conducted and the data was analyzed using a thematic approach. The themes identified in the interviews were then cross-referenced with the data discovered in the questionnaire survey and literature review. The findings provide a clear indication that the implementation of a QMS has a positive effect on construction performance in the NWE. Immediate improvements in efficiency of a construction organization when implementing a QMS were discovered, including greater managerial control and the recording and reduction in defects. Long term effects of changing company attitude by setting out company requirements and responsibilities through highlighting the significance of quality, and furthermore encouraging a culture of co-operation and teamwork, were also proven to increase construction performance as time progresses. To further enhance this research the focus could be on the whole of the UK. However, a greater amount of time would be required to gain the required representative sample. Furthermore, although the questionnaire survey was distributed equally within the selected sample, a greater number of respondents working for contractors responded. Therefore, the respondents of the questionnaire survey were not equal in terms of organization (client, contractor, sub-contractor, project manager). According to the best knowledge of the authors and through searching many sources, there are no specific studies examining QMS and their effect on construction performance in the UK and particularly in the NWE. Therefore, it is believed the study is the first of its kind. The study discovered many findings that can be considered as a contribution to practice and theory. Moreover, it can be considered as a fundamental base for future studies in this research area. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group

Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%

Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)

Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the $h_b(1P)$ spin-singlet partner of the P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications

Measurement of the relative rate of prompt χc0, χc1 and χc2 production at √s=7TeV

Prompt production of charmonium χc0, χc1 and χc2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of √s=7TeV. The χc mesons are identified through their decay to J/ψγ, with J/ψ→μ+mu− using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χc1 and χc2 in the rapidity range 2.0<y<4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χc0 meson production at a hadron collider is also presented