382 research outputs found
Nonlinear Isometries on Schatten- p
Let H be a complex Hilbert space; denote by Alg and p(H) the atomic nest algebra associated with the atomic nest on H and the space of Schatten-p class operators on, H respectively. Let p(H)∩Alg be the space of Schatten-p class operators in Alg . When 1≤p<+∞ and p≠2, we give a complete characterization of nonlinear surjective isometries on p(H)∩Alg . If p=2, we also prove that a nonlinear surjective isometry on 2(H)∩Alg is the translation of an orthogonality preserving map
Digital Divide: Adoption of Internet in China
With the development of information and communications technology (ICTs), Internet has been one of the major driving forces of the new economy. Nevertheless, access to the new technology remains extremely unequally distributed across and within societies, and there have a good deal of popular discussions about this “digital divide” in academia and business communities of every society. This study provides empirical evidence on China’s Internet development and diffusion in recent years. Findings show that there is a clear digital divide among the nation’s three economic zones, and while the growth rate for new Internet users is accelerating and the infrastructure of network is improving, the digital divide is growing narrower. In addition, by undertaking a set of regression analysis, the paper also finds that income and education play a critical role in shaping the divide. Based on the result, the paper offers some related policy suggestions to promote a wider diffusion of internet in poorer regions
Generalized Jordan Semitriple Maps on Hilbert Space Effect Algebras
Let ℰ(H) be the Hilbert space effect algebra on a Hilbert space H with dimH≥3, α,β two positive numbers with 2α+β≠1 and Φ:ℰ(H)→ℰ(H) a bijective map. We show that if Φ(AαBβAα)=Φ(A)αΦ(B)βΦ(A)α holds for all A,B∈ℰ(H), then there exists a unitary or an antiunitary operator U on H such that Φ(A)=UAU* for every A∈ℰ(H)
Is epinephrine still the drug of choice during cardiac arrest in the emergency department of the hospital? A meta-analysis
Epinephrine is the first-line emergency drug for cardiac arrest and anaphylactic reactions but is reported to be associated with many challenges resulting in its under- or improper utilization. Therefore, in this meta-analysis, the efficacy and safety of epinephrine as a first-line cardiac emergency drug for both out-of-hospital and in-hospital patients was assessed. Pertinent articles were searched in central databases like PubMed, Scopus, and Web of Science, using appropriate keywords as per the PRISMA guidelines. Retrospective and prospective studies were included according to the predefined PICOS criteria. RevMan and MedCalc software were used and statistical parameters such as odds ratio and risk ratio were calculated. Twelve clinical trials with a total of 208,690 cardiac arrest patients from 2000 to 2022 were included, in accordance with the chosen inclusion criteria. In the present meta-analysis, a high odds ratio (OR) value of 3.67 (95 % CI 2.32–5.81) with a tau2 value of 0.64, a chi2 value of 12,446.86, df value of 11, I2 value of 100 %, Z-value 5.53, and a p-value < 0.00001 were reported. Similarly, the risk ratio of 1.89 (95 % CI 1.47–2.43) with a tau2 value of 0.19, chi2 value of 11,530.67, df value of 11, I2 value of 100 %, Z-value of 4.95, and p-value < 0.000001. The present meta-analysis strongly prefers epinephrine injection as the first cardiac emergency drug for both out-of-hospital and in-hospital patients during cardiac arrest
External Application of Traditional Chinese Medicine for Venous Ulcers: A Systematic Review and Meta-Analysis
Objective. To evaluate the effectiveness of external application of traditional Chinese medicine (EA-TCM) on venous ulcers. Methods. Seven databases were searched until April 2015 for randomized controlled trials (RCTs) of EA-TCM for venous ulcers. Risk of bias was assessed using Cochrane Handbook guidelines. Study outcomes were presented as risk ratios (RRs) for dichotomous data or mean differences (MDs) for continuous data. Results. Sixteen of 193 potentially relevant trials met the inclusion criteria; however, their methodological qualities were low. Comparison of the same intervention strategies revealed significant differences in total effectiveness rates between EA-TCM and conventional therapy groups (RR = 1.22, 95% confidence interval [CI] = 1.16–1.29, and P<0.00001). Compared to conventional therapy, EA-TCM combined with conventional therapy had a superior total effectiveness rate (RR = 1.11, 95% CI = 1.04–1.19, and P=0.003). There were no significant differences in recurrence rates during followup and final pain measurements between the experimental and those in the control groups (RR = 0.86, 95% CI = 0.31–2.39, and P=0.85; MD −0.75, 95% CI = −2.15–0.65, and P=0.29). Conclusion. The evidence that EA-TCM is an effective treatment for venous ulcers is encouraging, but not conclusive due to the low methodological quality of the RCTs. Therefore, more high-quality RCTs with larger sample sizes are required
Role resources and work-family enrichment: The role of work engagement
The majority of work-family research has focused on negative spillover between demands and outcomes and between the work and family domains (e.g., work-family conflict; see review by Eby, Casper, Lockwood, Bordeaux, & Brinley, 2005). The theory that guided this research was in most cases role stress theory (Greenhaus & Beutell, 1985) or the role scarcity hypothesis (Edwards & Rothbard, 2000). However, according to spillover theory, work-related activities and satisfaction also affect non-work performance, and vice versa. Recently, in line with the positive psychology movement (Seligman & Csikszentmihalyi, 2000), work-family interaction research has also included concepts of positive spillover (Bakker & Schaufeli, 2008; Grzywacz & Marks, 2000). This emerging focus supplements the dominant conflict perspective by identifying new ways of cultivating human resource strength
Element Replacement Approach by Reaction with Lewis Acidic Molten Salts to Synthesize Nanolaminated MAX Phases and MXenes
Nanolaminated materials are important because of their exceptional properties
and wide range of applications. Here, we demonstrate a general approach to
synthesize a series of Zn-based MAX phases and Cl-terminated MXenes originating
from the replacement reaction between the MAX phase and the late transition
metal halides. The approach is a top-down route that enables the late
transitional element atom (Zn in the present case) to occupy the A site in the
pre-existing MAX phase structure. Using this replacement reaction between Zn
element from molten ZnCl2 and Al element in MAX phase precursors (Ti3AlC2,
Ti2AlC, Ti2AlN, and V2AlC), novel MAX phases Ti3ZnC2, Ti2ZnC, Ti2ZnN, and V2ZnC
were synthesized. When employing excess ZnCl2, Cl terminated MXenes (such as
Ti3C2Cl2 and Ti2CCl2) were derived by a subsequent exfoliation of Ti3ZnC2 and
Ti2ZnC due to the strong Lewis acidity of molten ZnCl2. These results indicate
that A-site element replacement in traditional MAX phases by late transition
metal halides opens the door to explore MAX phases that are not
thermodynamically stable at high temperature and would be difficult to
synthesize through the commonly employed powder metallurgy approach. In
addition, this is the first time that exclusively Cl-terminated MXenes were
obtained, and the etching effect of Lewis acid in molten salts provides a green
and viable route to prepare MXenes through an HF-free chemical approach.Comment: Title changed; experimental section and discussion revise
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