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Flow-mediated dilation reference values for evaluation of endothelial function and cardiovascular health
Get PDFAims: Endothelial function is essential for cardiovascular health, and flow-mediated dilation (FMD) is an established technique to measure it. This paper is to assess FMD values in apparently healthy individuals and provide reference values to facilitate wider clinical use.Methods and Results: In 1,579 apparently healthy individuals (aged 18-76), fasted FMD values (data from 44 studies, 6 institutions, 22 operators) were normally distributed and inversely univariately correlated with age, body-mass-index, glucose, cholesterol, blood pressure, and brachial artery diameter. Significant multivariate predictors of FMD were age (-0.4%/decade), BMI (0.04%/kg/m2), smoking (-0.7%), and brachial artery diameter (-0.44%/mm) that together explained 19% of the variability independent of operator, institution or ultrasound machine. Individuals in the high FMD tertile (>6.8%) were younger, had smaller brachial artery diameter, lower blood pressure and cholesterol. In individuals with low- and intermediate fatal cardiovascular risk (SCORE), 26% and 53% of individuals, respectively, had FMD values in the low tertile (c=0.841, p) showed that FMD of >6.5% excluded CAD (95% sensitivity; 60% specificity) and FMD I2=0.97) FMD in healthy individuals was on average 6.4% (95%CI: 6.2%, 6.7%) with no significant differences between countries but a significant age-dependent decline (-0.3%/decade, R2=0.13).Conclusions: We provide an age-adapted frame of FMD reference intervals in apparently healthy individuals for use as a biomarker of CV health. As the degree of vascular endothelial function integrates environmental and genetic factors with classical CV risk factors, FMD may more comprehensively classify individuals with and without standard modifiable cardiovascular risk factors and serve as a target for cardiovascular prevention.</p
Systematics of E2 strength in the sd-shell with the valence-space in-medium similarity renormalization group
Get PDFBackground: Recent developments in {\it ab initio} nuclear theory demonstratepromising results in medium- to heavy-mass nuclei. A particular challenge formany of the many-body methodologies, however, is an accurate treatment of theelectric-quadrupole, , strength associated with collectivity. Purpose: Thevalence-space in-medium similarity renormalization group (VS-IMSRG) is aparticularly powerful method for accessing medium- and high-mass nuclei but hasbeen found to underpredict strengths. The purpose of this work is toevaluate the isospin dependence of this underprediction. Methods: We perform asystematic comparison of valence-space in-medium similarity renormalizationgroup (VS-IMSRG) calculations with available literature. We make use ofisoscalar and isovector contributions to the matrix elements to assessisoscalar and isovector contributions to the missing strength. Results: It isfound that the strength is consistent throughout, , and pairs within the -shell.Furthermore, no isovector contribution to the deficiency is identified.Conclusions: A comparison with toy-models and coupled-cluster calculations isused to discuss potential origins of the missing strength, which arises frommissing many-particle, many-hole excitations out of the model space. Theabsence of any significant isovector contribution to the missing strengthindicates that the strength discrepancy, and therefore any correction, islargely independent of the isospin of the nuclei in question
Halo Properties in Helium Nuclei from the Perspective of Geometrical Thermodynamics
Get PDFThe nuclear matter and charge radii of the helium isotopes (A=4,6,8) are calculated by quantitative geometrical thermodynamics (QGT) taking as input the symmetry of the alpha-particle, the very weak binding (and hence halo nature) of the heavier helium isotopes, and a characteristic length scale given by the proton size. The results follow by considering each isotope in its ground state, with QGT representing each system as a maximum entropy configuration that conforms to the Holographic Principle. This allows key geometric parameters to be determined from the number of degrees of freedom available. QGT treats 6He as a 4He core plus a concentric neutron shell comprising a holomorphic pair of neutrons, and the 8He neutron halo is treated as a holomorphic pair of holomorphic pairs. Considering that the information content of each system allows a correlation angle of 2/3 between the holomorphic entities to be inferred, then the charge radii of the three isotopes can be calculated from the displacement of the 4He core from the centre of mass. The calculations for the charge and matter radii of 4,6,8He agree closely with observed values. Similar QGT calculation of the sizes of the self-conjugate A=4n nuclei {4He, 8Be, 12C, 16O, 20Ne, 24Mg, 28Si, 32S, 36Ar, 40Ca} also agree well with experiment
Knowledge management practices of tourism consultants: A project ecology perspective
Get PDFThis study advances the contextual understanding of knowledge management practices adopted by tourism consultants in the setting of tourism development projects. It goes beyond the traditional understanding of the bounded nature of firms to analyse knowledge management issues through a project-based multi-layered perspective, namely project ecology. An innovative participant-observation methodology is utilised to study 15 episodic projects at three tourism development companies over a 12-month period. This provides an insider perspective to enhance understanding of the knowledge management practices and collaborations of tourism consultants. The study reveals two underlying logics that shape knowledge management practices: the logics of creativity and accumulation. The findings exhibit how knowledge management is moulded by the practices within, and interactions among, the four tiers of a multi-level project-specific contextual framework.•Analysis of project knowledge management focussed on the holistic social contexts of episodic projects instead of the bounded firm or the destination networks.•Innovative participant observation fieldwork took place in 15 tourism development projects over 12 months.•This is the first study that utilises the project ecology perspective in tourism research.•Two contrasting but interacted logics of knowledge management practices adopted by tourism consultants in tourism development projects are identified: the logic of creativity and the logic of accumulation
The synchronised dance of the Magellanic Clouds' star formation history
No full textWe use the SMASH survey to obtain unprecedented deep photometry reaching downto the oldest main sequence turn-offs in the colour-magnitude diagrams (CMDs)of the Small Magellanic Cloud (SMC) and quantitatively derive its starformation history (SFH) using CMD fitting techniques. We identify fivedistinctive peaks of star formation in the last 3.5 Gyr, at 3, 2,1.1, 0.45 Gyr ago, and one presently. We compare these to the SFHof the Large Magellanic Cloud (LMC) finding unequivocal synchronicity, withboth galaxies displaying similar periods of enhanced star formation over thepast 3.5 Gyr. The parallelism between their SFHs indicates that tidalinteractions between the MCs have recurrently played an important role in theirevolution for at least the last 3.5 Gyr, tidally truncating the SMC andshaping the LMC's spiral arm. We show, for the first time, an SMC-LMCcorrelated SFH at recent times in which enhancements of star formation arelocalised in the northern spiral arm of the LMC, and globally across the SMC.These novel findings should be used to constrain not only the orbital historyof the MCs but also how star formation should be treated in simulations
How does social context influence appraisal and help-seeking for potential cancer symptoms in adults aged 50 and over? A qualitative interview study
No full textObjectiveTo investigate how social context and social network activation influence appraisal and help-seeking for symptoms potentially indicative of cancer.MethodsSemi-structured telephone interview study. Community dwelling adults who had experienced at least one symptom potentially indicative of cancer within the last month were sampled from a national symptom survey.ResultsThirty-four interviews were conducted. Participants looked to peers and wider society to judge whether symptoms might be normal for their age. Involvement of others in symptom appraisal promoted an active management strategy, such as contacting a healthcare professional or trying a medication. There were practical, emotional, attitudinal, normative and moral barriers to involving others. Cancer narratives from significant others, public health campaigns and the media influenced symptom appraisal. Participants held mental representations of types of people who get cancer, for example, smokers and unfit people. This had two consequences. First, participants did not identify themselves as a candidate for cancer; impeding help-seeking. Second, social judgements about lifestyle introduced stigma.ConclusionInvolving friends/family in symptom appraisal facilitates help-seeking but barriers exist to involving others. Campaigns to promote earlier cancer diagnosis should incorporate age-appropriate narratives, address misconceptions about ‘types’ of people who get cancer and tackle stigma about lifestyle factors.<br
UAV-enabled Edge Computing for Optimal Task Distribution in Target Tracking
Get PDF—Unmanned aerial vehicles (UAVs) are useful devices due to their great manoeuvrability for long-range outdoor target tracking. However, these tracking tasks can lead to sub-optimal performance due to high computation requirements and power constraints. To cope with these challenges, we design a UAV-based target tracking algorithm where computationally intensive tasks are offloaded to Edge Computing (EC) servers. We perform joint optimization by considering the trade-off between transmission energy consumption and execution time to determine optimal edge nodes for task processing and reliable tracking. The simulation results demonstrate the superiority of the proposed UAV-based target tracking on the predefined trajectory over several existing techniques. Index Terms—Edge computing (EC), task offloading, un-manned aerial vehicle (UAV
Power Allocation for FDMA-URLLC Downlink with Random Channel Assignment
Get PDF—Concerning ultra-reliable low-latency communication (URLLC) for the downlink operating in the frequency-division multiple-access with random channel assignment, a lightweight power allocation approach is proposed to maximize the number of URLLC users subject to transmit-power and individual user-reliability constraints. Provided perfect channel-state-information at the transmitter (CSIT), the proposed approach is proven to ensure maximized URLLC users. Assuming imperfect CSIT, the proposed approach still aims to maximize the URLLC users without compromising the individual user reliability by using a pessimistic evaluation of the channel gain. It is demonstrated , through numerical results, that the proposed approach can significantly improve the user capacity and the transmit-power efficiency in Rayleigh fading channels. With imperfect CSIT, the proposed approach can still provide remarkable user capacity at limited cost of transmit-power efficiency
A Low-Complexity Power Allocation Scheme for MIMO-NOMA Systems With Imperfect Channel Estimation
Get PDF—This paper considers a two-user downlink multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) system using minimum mean-squared error (MMSE) detection under imperfect channel estimation. By taking account of both errors in channel estimation and MMSE detection, we derive approximated users' capacities and design a closed-form power allocation scheme to maximize the minimum (max-min) of them. The design problem is equivalent to max-min optimization of users' signal-to-interference-plus-noise ratios (SINRs), and the solution can be obtained by SINR balancing. The proposed power allocation scheme involves solving two quadratic equations, and is easy to implement in practical applications. As compared with an existing robust MIMO-NOMA power allocation method based on generalized singular value decomposition and SINR balancing, the proposed one offers slightly worse bit-error-rate performance with much lower complexity
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