4,444 research outputs found
Levels of Multiplexity in Entrepreneur's Networks: Implications for Dynamism and Value Creation
© 2016 by De Gruyter. Relationships and networks are important to how entrepreneurs create value. However, many aspects about relationships and networks remain poorly understood because their characteristics are often reduced to one-dimensional variables or dichotomous measures. This paper unpacks the concept of multiplexity and proposes a hierarchy of four different levels (social, relational, strategic, and closed). Each level is associated with a different level of dynamism which governs how rapidly entrepreneurs can alter their network. The hierarchy of multiplexity and associated levels of dynamism, have implications regarding different value creation processes that are associated with these network conditions
Sexual health interventions delivered to participants by mobile technology: a systematic review and meta-analysis of randomised controlled trials
Background: The use of mobile technologies to prevent STIs is recognised as a promising approach worldwide; however, evidence has been inconclusive, and the field has developed rapidly. With about 1 million new STIs a day globally, up-to-date evidence is urgently needed. // Objective: To assess the effectiveness of mobile health interventions delivered to participants for preventing STIs and promoting preventive behaviour. // Methods: We searched seven databases and reference lists of 49 related reviews (January 1990–February 2020) and contacted experts in the field. We included randomised controlled trials of mobile interventions delivered to adolescents and adults to prevent sexual transmission of STIs. We conducted meta-analyses and assessed risk of bias and certainty of evidence following Cochrane guidance. // Results: After double screening 6683 records, we included 22 trials into the systematic review and 20 into meta-analyses; 18 trials used text messages, 3 used smartphone applications and 1 used Facebook messages as delivery modes. The certainty of evidence regarding intervention effects on STI/HIV occurrence and adverse events was low or very low. There was moderate certainty of evidence that in the short/medium-term text messaging interventions had little or no effect on condom use (standardised mean differences (SMD) 0.02, 95% CI −0.09 to 0.14, nine trials), but increased STI/HIV testing (OR 1.83, 95% CI 1.41 to 2.36, seven trials), although not if the standard-of-care control already contained an active text messaging component (OR 1.00, 95% CI 0.68 to 1.47, two trials). Smartphone application messages also increased STI/HIV testing (risk ratio 1.40, 95% CI 1.22 to 1.60, subgroup analysis, two trials). The effects on other outcomes or of social media or blended interventions is uncertain due to low or very low certainty evidence
Pulsed electromagnetic energy treatment offers no clinical benefit in reducing the pain of knee osteoarthritis: a systematic review
Background
The rehabilitation of knee osteoarthritis often includes electrotherapeutic modalities as well as advice and exercise. One commonly used modality is pulsed electromagnetic field therapy (PEMF). PEMF uses electro magnetically generated fields to promote tissue repair and healing rates. Its equivocal benefit over placebo treatment has been previously suggested however recently a number of randomised controlled trials have been published that have allowed a systematic review to be conducted.
Methods
A systematic review of the literature from 1966 to 2005 was undertaken. Relevant computerised bibliographic databases were searched and papers reviewed independently by two reviewers for quality using validated criteria for assessment. The key outcomes of pain and functional disability were analysed with weighted and standardised mean differences being calculated.
Results
Five randomised controlled trials comparing PEMF with placebo were identified. The weighted mean differences of the five papers for improvement in pain and function, were small and their 95% confidence intervals included the null.
Conclusion
This systematic review provides further evidence that PEMF has little value in the management of knee osteoarthritis. There appears to be clear evidence for the recommendation that PEMF does not significantly reduce the pain of knee osteoarthritis
Pressure dependent electronic properties of MgO polymorphs: A first-principles study of Compton profiles and autocorrelation functions
The first-principles periodic linear combination of atomic orbitals method
within the framework of density functional theory implemented in the CRYSTAL06
code has been applied to explore effect of pressure on the Compton profiles and
autocorrelation functions of MgO. Calculations are performed for the B1, B2,
B3, B4, B8_1 and h-MgO polymorphs of MgO to compute lattice constants and bulk
moduli. The isothermal enthalpy calculations predict that B4 to B8_1, h-MgO to
B8_1, B3 to B2, B4 to B2 and h-MgO to B2 transitions take place at 2, 9, 37, 42
and 64 GPa respectively. The high pressure transitions B8_1 to B2 and B1 to B2
are found to occur at 340 and 410 GPa respectively. The pressure dependent
changes are observed largely in the valence electrons Compton profiles whereas
core profiles are almost independent of the pressure in all MgO polymorphs.
Increase in pressure results in broadening of the valence Compton profiles. The
principal maxima in the second derivative of Compton profiles shifts towards
high momentum side in all structures. Reorganization of momentum density in the
B1 to B2 structural phase transition is seen in the first and second
derivatives before and after the transition pressure. Features of the
autocorrelation functions shift towards lower r side with increment in
pressure.Comment: 19 pages, 8 figures, accepted for publication in Journal of Materials
Scienc
A companion to a quasar at redshift 4.7
There is a growing consensus that the emergence of quasars at high redshifts
is related to the onset of galaxy formation, suggesting that the detection of
concentrations of gas accompanying such quasars should provide clues about the
early history of galaxies. Quasar companions have been recently identified at
redshifts up to . Here we report observations of Lyman-
emission (a tracer of ionised hydrogen) from the companion to a quasar at
=4.702, corresponding to a time when the Universe was less than ten per cent
of its present age. We argue that most of the emission arises in a gaseous
nebula that has been photoionised by the quasar, but an additional component of
continuum light -perhaps quasar light scattered from dust in the companion
body, or emission from young stars within the nebula- appears necessary to
explain the observations. These observations may be indicative of the first
stages in the assembly of galaxy-sized structures.Comment: 8 pages, 4 figures, plain LaTeX. Accepted for publication in Natur
Isothermal Recombinase Polymerase amplification (RPA) of Schistosoma haematobium DNA and oligochromatographic lateral flow detection
© 2015 Rosser et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article
Longer fixation duration while viewing face images
The spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity. We recorded monkeys’ saccadic eye movements as they freely viewed monkey face and natural scene images. The face and natural scene images attracted similar number of fixations, but viewing of faces was accompanied by longer fixations compared with natural scenes. These longer fixations were dependent on the context of facial features. The duration of fixations directed at facial contours decreased when the face images were scrambled, and increased at the later stage of normal face viewing. The results suggest that face and natural scene images can generate different patterns of visuomotor activity. The extra fixation duration on faces may be correlated with the detailed analysis of facial features
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