Let μ be a nonnegative Radon measure on Rd, which only satisfies the polynomial growth condition. Under this assumption, the authors obtain some weighted weaktype estimates for the commutators generated by the multil...Let μ be a nonnegative Radon measure on Rd, which only satisfies the polynomial growth condition. Under this assumption, the authors obtain some weighted weaktype estimates for the commutators generated by the multilinear CalderSn-Zygmund op- erators and RBMO(μ) functions.展开更多
Let μ be a non-negative Radon measure on R^d which satisfies some growth conditions. The boundedness of multilinear Calderon-Zygmund singular integral operator T and its commutators with RBMO functions on Morrey-Herz...Let μ be a non-negative Radon measure on R^d which satisfies some growth conditions. The boundedness of multilinear Calderon-Zygmund singular integral operator T and its commutators with RBMO functions on Morrey-Herz spaces are obtained if T is bounded from L^1(μ)χ…χ L^1(μ) to L1/m,∞(μ).展开更多
In the paper we obtain vector-valued inequalities for Calderon-Zygmund operator, simply CZO on Herz space and weak Herz space. In particular, we obtain vector-valued inequalities for CZO on L^q(R^d,|x|^α d μ)spa...In the paper we obtain vector-valued inequalities for Calderon-Zygmund operator, simply CZO on Herz space and weak Herz space. In particular, we obtain vector-valued inequalities for CZO on L^q(R^d,|x|^α d μ)space, with 1〈q〈∞,-n〈α〈n(q-1),and on L^1,∞ (R^d,|x|^α d μ)space,with -n〈α〈0.展开更多
Let μ be a non-negative Radon measure on Rd which only satisfies the following growth condition that there exists a positive constant C such that μ(B(x,r)) ≤ Crn?for all x∈ Rd, r > 0 and some fixed n ∈ (0,d]. ...Let μ be a non-negative Radon measure on Rd which only satisfies the following growth condition that there exists a positive constant C such that μ(B(x,r)) ≤ Crn?for all x∈ Rd, r > 0 and some fixed n ∈ (0,d]. This paper is interested in the properties of the iterated commutators of multilinear singular integral operators on Morrey spaces?.Precisely speaking, we show that the iterated commutators generated by multilinear singular integrals operators are bounded from to where (Regular Bounded Mean Oscillation space) and 1 qj ≤ pj ∞ with 1/p = 1/p1 + ... + 1/pm and 1/q = 1/q1+ ... + 1/qm.展开更多
The authors give a natural definition of Morrey spaces for Radon measures which may be non-doubling but satisfy certain growth condition, and investigate the boundedness in these spaces of some classical operators in ...The authors give a natural definition of Morrey spaces for Radon measures which may be non-doubling but satisfy certain growth condition, and investigate the boundedness in these spaces of some classical operators in harmonic analysis and their vector-valued extension.展开更多
The boundedness in Lebesgue spaces for commutators generated by multilinear singular integrals and RMBO(μ) functions of Tolsa with non-doubling measures is obtained, provided that ∥μ∥ = ∞ and multilinear singular...The boundedness in Lebesgue spaces for commutators generated by multilinear singular integrals and RMBO(μ) functions of Tolsa with non-doubling measures is obtained, provided that ∥μ∥ = ∞ and multilinear singular integrals are bounded from L 1(μ) × L 1(μ) to L 1/2,∞(μ).展开更多
Let μ be a non-negative Radon measure on R^d which satisfies only some growth conditions. Under this assumption, the boundedness in some Hardy-type spaces is established for a class of maximal Calderón-Zygmund o...Let μ be a non-negative Radon measure on R^d which satisfies only some growth conditions. Under this assumption, the boundedness in some Hardy-type spaces is established for a class of maximal Calderón-Zygmund operators and maximal commutators which are variants of the usual maximal commutators generated by Calder6ón- Zygmund operators and RBMO(μ) functions, where the Hardytype spaces are some appropriate subspaces, associated with the considered RBMO(μ) functions, of the Hardv soace H^I(μ) of Tolsa.展开更多
Letμbe a nonnegative Radon measure on R^d which only satisfiesμ(B(x,r))≤C_0r^n for all x∈R^d,r>0,and some fixed constants C_0>0 and n∈(0,d].In this paper,some weighted weak type estimates with A_(p,(log L)~...Letμbe a nonnegative Radon measure on R^d which only satisfiesμ(B(x,r))≤C_0r^n for all x∈R^d,r>0,and some fixed constants C_0>0 and n∈(0,d].In this paper,some weighted weak type estimates with A_(p,(log L)~σ)~ρ(μ) weights are established for the commutators generated by Calder■n-Zygmund singular integral operators with RBMO(μ) functions.展开更多
Let μ be a Radon measure on Rd which may be non-doubling. The only condition that μ must satisfy is μ(B(x,r)) ≤ Urn for all x∈Rd, r 〉 0 and for some fixed 0 〈 n 〈 d. In this paper, under this assumption, w...Let μ be a Radon measure on Rd which may be non-doubling. The only condition that μ must satisfy is μ(B(x,r)) ≤ Urn for all x∈Rd, r 〉 0 and for some fixed 0 〈 n 〈 d. In this paper, under this assumption, we prove that 0-type Calder6n-Zygmund operator which is bounded on L2 (μ) is also bounded from L^∞(μ) into RBMO (μ) and from Hb (μ) into L1(μ). According to the interpolation theorem introduced by Tolsa, the LP(μ)-boundedness (1 〈 p 〈 ∞) is established for θ-type Calder6n-Zygmund operators. Via a sharp maximal operator, it is shown that commutators and multilinear commutators of θ-type CMderθn-Zygmundoperator with RBMO (μ) function are bounded on LP(μ) (1 〈 p 〈 ∞).展开更多
Let (y, d, dλ) be (Rn, |·|,μ), where |·| is the Euclidean distance, μ is a nonnegative Radon measure on Rn satisfying the polynomial growth condition, or the Gauss measure metric space (Rn, |...Let (y, d, dλ) be (Rn, |·|,μ), where |·| is the Euclidean distance, μ is a nonnegative Radon measure on Rn satisfying the polynomial growth condition, or the Gauss measure metric space (Rn, |·|,dγ), or the space (S, d, p), where S - Rn×R+ is the (ax + b)-group, d is the left-invariant Riemannian metric and p is the right Haar measure on S with exponential growth. In this paper, the authors introduce and establish some properties of the atomic Hardy-type spaces {Xs(Y))0〈s≤∞ and the BM0-type spaces {BM0(y, s)}0〈s≤∞. Let Hi(Y) be the known atomic Hardy space and L01(y) the subspace of f ∈ L1(Y) with integral 0. The authors prove that the dual space of Xs(Y) is SM0(Y,s) when s∈ (0, ∞), Xs(Y) = H1(Y) when s ∈ (0, 1], and X∞(y) = L01(Y) (or L1(Y)). As applications, the authors show that if T is a linear operator bounded from H1 (Y) to L1 (Y) and from L1(y) to L1,∞(Y), then for all r ∈ (1, ∞) and s ∈ (r, ∞], T is bounded from Xr(y) to the Lorentz space L1,8(y), which applies to the Calderon-Zygmund operator on (Rn, |·|,μ), the imaginary powers of the 0rnstein-Uhlenbeck operator on (Rn, |·|,dγ) and the spectral operator associated with the spectral multiplier on (S, d, p). All these results generalize the corresponding results of Sweezy, Abu-Shammala and Torchinsky on Euclidean spaces.展开更多
Under the assumption that μ is a non-doubling measure on R^d which only satisfies the polynomial growth condition, the authors obtain the boundedness of the multilinear fractional integrals on Morrey spaces, weak-Mor...Under the assumption that μ is a non-doubling measure on R^d which only satisfies the polynomial growth condition, the authors obtain the boundedness of the multilinear fractional integrals on Morrey spaces, weak-Morrey spaces and Lipschitz spaces associated with it, which, in the case when μ is the d-dimensional Lebesgue measure, also improve the known results.展开更多
Let μ be a nonnegative Radon measure on Rd which satisfies the polynomial growth condition that there exist positive constants Co and n ∈ (0,d) such that, for all x ∈ Rd and r 〉 0, μ(B(x, r))≤ Corn, where ...Let μ be a nonnegative Radon measure on Rd which satisfies the polynomial growth condition that there exist positive constants Co and n ∈ (0,d) such that, for all x ∈ Rd and r 〉 0, μ(B(x, r))≤ Corn, where B(x, r) denotes the open ball centered at x and having radius r. In this paper, we show that, if μ(Rd) 〈∞, then the boundedness of a Calderdn-Zygmund operator T on L2(μ) is equivalent to that of T from the localized atomic Hardy space h1(μ) to L1,∞(μ) or from h1(μ) to L1(μ).展开更多
Let μ be a Borel measure on R^d which may be non doubling. The only condition that μ must satisfy is μ(Q) ≤ col(Q)^n for any cube Q belong to R^d with sides parallel to the coordinate axes and for some fixed ...Let μ be a Borel measure on R^d which may be non doubling. The only condition that μ must satisfy is μ(Q) ≤ col(Q)^n for any cube Q belong to R^d with sides parallel to the coordinate axes and for some fixed n with 0 〈 n ≤ d. The purpose of this paper is to obtain a boundedness property of fractional integrals in Hardy spaces H^1(μ).展开更多
Introduction: COVID-19 is a pandemic disease caused by the coronavirus SARS-COV2 appeared in China in 2019. The aim of the study was to evaluate the practice of barrier measures against COVID-19 and to identify associ...Introduction: COVID-19 is a pandemic disease caused by the coronavirus SARS-COV2 appeared in China in 2019. The aim of the study was to evaluate the practice of barrier measures against COVID-19 and to identify associated factors among diabetics followed at Departmental University Hospital Center Ouémé-Plateau, Benin, in 2021. Methods: This was a cross-sectional study conducted from June to August 2021, including diabetics aged 18 and over, hospitalized or received for medical visits in the department of medicine at the target hospital. Data were collected during an interview with each participant thanks to a questionnaire. “Good practice” was defined as regular practice of at least two of three barrier measures: hand washing, physical distancing and mask-wearing. Results: A total of 110 diabetics were included with a female predominance (55.5%) and a mean age of 57 ± 11.3 years. Among them, 89.1% washed their hands, 41.8% respected physical distancing and 12.7% wore a mask. The proportion of good practice was 47.3%. Only 5 practiced the three barrier measures. Only age group was associated with good practice. Conclusion: The study showed a low proportion of good practice of barrier measures against COVID-19 among diabetic people surveyed. It is important to continue the action for COVID-19 prevention among diabetic people in the targeted hospital and in other hospitals in Benin.展开更多
Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the speci...Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the specific disasterreduction effects of these measures and their economic,social and ecological benefits is yet to be performed.The western region of Sichuan Province frequentlysuffers from geohazards such as debris flow, and thegovernment has adopted many mitigation measures.This study assessed the benefits of debris flowmitigation measures and identified the key influencingfactors via a field-based study conducted in 81 villagesin western Sichuan province, China. A framework forthe evaluation of the benefits of rural debris flowmitigation measures was constructed andquantitatively evaluated using a survey. Snowballsampling was performed to recruit 81 village leadersand 468 farmers. The results showed that managementand engineering measures were the main methodsused to mitigate debris flow;ecological measures wereauxiliary. The average satisfaction scores of farmers forthese three types of measures were 4.07, 3.90, and 3.56,respectively (as measured on a five-point Likert scale).In contrast, in terms of the benefits of these mitigationmeasures, only a small proportion of villages (11.11%)obtained a high level of comprehensive benefits fromthe debris flow mitigation measures, while the majority(88.89%) received medium to low-level benefits. Toimprove this situation, we further studied and foundthat the main factors that restricted villages fromachieving high-level comprehensive benefits were theunpredictable nature of debris flows, labour forceoutflow and remoteness. Effective control measures, agood economic environment and strong governmentassistance were reported as crucial factors forimproving these comprehensive benefits. This studyprovides socio-scientific references for decisionmakingon rural debris flow mitigation measures while keeping villages at the centre of economic development.展开更多
Context: COVID-19 can spread rapidly in haemodialysis centres, leading to fatal outcomes. Implementing physical measures is crucial in limiting the spread of infection. Aims: To assess adherence to physical measures a...Context: COVID-19 can spread rapidly in haemodialysis centres, leading to fatal outcomes. Implementing physical measures is crucial in limiting the spread of infection. Aims: To assess adherence to physical measures against SARS-Cov2 in haemodialysis patients. Methods and Material: From 13 to 19 July 2021, we administered the questionnaire to haemodialysis patients during or immediately after the dialysis session. The dependent variables were adherence to wearing masks, hand washing outside the dialysis centre, social distancing of at least 1.5 meters, and cough and sneeze hygiene. Statistical Analysis Used: Data were analyzed using Epi info software;descriptive statistics were presented as mean, headcount, and percentage;related factors were determined by multi-logistic regression. The significance level was 5%. The Health Research Ethics Committee approved the research protocol. Results: 142 patients were included (mean age: 42.5 ± 14 years). Wearing masks, hand-washing, social distancing, and coughing and sneezing hygiene were observed by 88%, 75%, 47%, and 60% of patients, respectively. Conclusion: Wearing masks was the most respected physical measure, while social distancing was the least respected.展开更多
This research focuses on the effects of migration on the TB infection rate and its prevention in Saudi Arabia, which has a large number of expatriates from TB-affected countries. Despite, based on the current global s...This research focuses on the effects of migration on the TB infection rate and its prevention in Saudi Arabia, which has a large number of expatriates from TB-affected countries. Despite, based on the current global statistics of TB occurrence, it is evident that the national incidence of TB has reduced from 10.55 per 100,000 in 2015 to 8.36 per 100,000 in 2019;despite this, there are still some difficulties because migrants bring new strains of Mycobacterium tuberculosis. Hindrances, including language barriers and perceived immigration status, hinder patients from seeking medical attention or doctors from diagnosing diseases. Each patient and each cultural group need special attention to public health, enhancing living circumstances, and health care support. Community participation, inclusion of TB control programs into functional healthcare facilities, and the functioning of TB programs need to be stressed to address TB issues. Considering the focus on social, economic, and cultural approaches, the country can make severe advancements in TB control and population protection. This holistic analysis is critical for a long-term effective strategy to combat TB in the Kingdom.展开更多
Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail med...Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.展开更多
BACKGROUND Intravenous infusion is a common method of drug administration in clinical practice.Errors in any aspect of the infusion process,from the verification of medical orders,preparation of the drug solution,to i...BACKGROUND Intravenous infusion is a common method of drug administration in clinical practice.Errors in any aspect of the infusion process,from the verification of medical orders,preparation of the drug solution,to infusion by nursing staff,may cause adverse infusion events.AIM To analyzed the value of improving nursing measures and enhancing nursing management to reduce the occurrence of adverse events in pediatric infusion.METHODS The clinical data of 130 children who received an infusion in the pediatric department of our hospital from May 2020 to May 2021 were analyzed and divided into two groups according to the differences in nursing measures and nursing management:65 patients in the control group received conventional nursing and nursing management interventions,while 65 patients in the observation group received improved nursing measure interventions and enhanced nursing management.The occurrence of adverse events,compliance of children,satisfaction of children’s families,and complaints regarding the transfusion treatment were recorded in both groups.RESULTS The incidence of fluid extravasation and infusion set dislodgement in the observation group were 3.08%and 1.54%,respectively,which were significantly lower than 12.31%and 13.85%in the control group(P<0.05),while repeated punctures and medication addition errors in the observation group were 3.08%and 0.00%,respectively,which were lower than 9.23%and 3.08%in the control group,but there was no significant difference(P>0.05).The compliance rate of children in the observation group was 98.46%(64/65),which was significantly higher than 87.69%(57/65)in the control group,and the satisfaction rate of children’s families was 96.92%(63/65),which was significantly higher than 86.15%(56/65)in the control group(P<0.05).The observation group did not receive any complaints from the child’s family,whereas the control group received four complaints,two of which were due to the crying of the child caused by repeated punctures,one due to the poor attitude of the nurse,and one due to medication addition errors,with a cumulative complaint rate of 6.15%.The cumulative complaint rate of the observation group was significantly lower than that of the control group(P<0.05).CONCLUSION Improving nursing measures and enhancing nursing management can reduce the incidence of fluid extravasation and infusion set dislodgement in pediatric patients,improve children’s compliance and satisfaction of their families,and reduce family complaints.展开更多
基金supported by National Natural Science Foundation of China (10701078)supported by National Science Foundation for Distinguished Young Scholars (10425106)
文摘Let μ be a nonnegative Radon measure on Rd, which only satisfies the polynomial growth condition. Under this assumption, the authors obtain some weighted weaktype estimates for the commutators generated by the multilinear CalderSn-Zygmund op- erators and RBMO(μ) functions.
基金Supported by the National Natural Science Foundation of China(10971228)Supported by the Science and Technology Innovation Plan for Graduate Students of Jiangsu Educational Department(CXZZll-0633)+1 种基金Supported by the Science and Technology Innovation Plan for Graduate Students of Nangtong University (YKC111051)Supported by the NSF of Nantong University(llZY002)
文摘Let μ be a non-negative Radon measure on R^d which satisfies some growth conditions. The boundedness of multilinear Calderon-Zygmund singular integral operator T and its commutators with RBMO functions on Morrey-Herz spaces are obtained if T is bounded from L^1(μ)χ…χ L^1(μ) to L1/m,∞(μ).
文摘In the paper we obtain vector-valued inequalities for Calderon-Zygmund operator, simply CZO on Herz space and weak Herz space. In particular, we obtain vector-valued inequalities for CZO on L^q(R^d,|x|^α d μ)space, with 1〈q〈∞,-n〈α〈n(q-1),and on L^1,∞ (R^d,|x|^α d μ)space,with -n〈α〈0.
文摘Let μ be a non-negative Radon measure on Rd which only satisfies the following growth condition that there exists a positive constant C such that μ(B(x,r)) ≤ Crn?for all x∈ Rd, r > 0 and some fixed n ∈ (0,d]. This paper is interested in the properties of the iterated commutators of multilinear singular integral operators on Morrey spaces?.Precisely speaking, we show that the iterated commutators generated by multilinear singular integrals operators are bounded from to where (Regular Bounded Mean Oscillation space) and 1 qj ≤ pj ∞ with 1/p = 1/p1 + ... + 1/pm and 1/q = 1/q1+ ... + 1/qm.
基金the 21st century COE program at Graduate School of Mathemtical Sciences The University of Tokyo and the sceond author is supported by Fjyukai foundation
文摘The authors give a natural definition of Morrey spaces for Radon measures which may be non-doubling but satisfy certain growth condition, and investigate the boundedness in these spaces of some classical operators in harmonic analysis and their vector-valued extension.
基金This work was partially supported by Scientific Research Fund of Hunan Provincial Education Department(Grant No.06B059)the Natural Science Foundation of Hunan Province of China(Grant No.06JJ5012)the National Natural Science Foundation of China(Grant Nos.60474070 and 10671062)
文摘The boundedness in Lebesgue spaces for commutators generated by multilinear singular integrals and RMBO(μ) functions of Tolsa with non-doubling measures is obtained, provided that ∥μ∥ = ∞ and multilinear singular integrals are bounded from L 1(μ) × L 1(μ) to L 1/2,∞(μ).
基金Program for New Century Excellent Talents in University(NCET-04-0142)of China
文摘Let μ be a non-negative Radon measure on R^d which satisfies only some growth conditions. Under this assumption, the boundedness in some Hardy-type spaces is established for a class of maximal Calderón-Zygmund operators and maximal commutators which are variants of the usual maximal commutators generated by Calder6ón- Zygmund operators and RBMO(μ) functions, where the Hardytype spaces are some appropriate subspaces, associated with the considered RBMO(μ) functions, of the Hardv soace H^I(μ) of Tolsa.
基金This work was partly supported by the National Natural Science Foundation of China (Grant No.10671210)the National Science Foundation for Distinguished Young Scholars (Grant No.10425106)the Program for New Century Excellent Talents in University of the Ministry of Education of China (Grant No.04-0142)
文摘Letμbe a nonnegative Radon measure on R^d which only satisfiesμ(B(x,r))≤C_0r^n for all x∈R^d,r>0,and some fixed constants C_0>0 and n∈(0,d].In this paper,some weighted weak type estimates with A_(p,(log L)~σ)~ρ(μ) weights are established for the commutators generated by Calder■n-Zygmund singular integral operators with RBMO(μ) functions.
基金Supported by National Natural Science Foundation of China (No.10371087)Natural Science Foundation of Education Committee of Anhui Province (No.KJ2011A138, No.KJ2012B116)
文摘Let μ be a Radon measure on Rd which may be non-doubling. The only condition that μ must satisfy is μ(B(x,r)) ≤ Urn for all x∈Rd, r 〉 0 and for some fixed 0 〈 n 〈 d. In this paper, under this assumption, we prove that 0-type Calder6n-Zygmund operator which is bounded on L2 (μ) is also bounded from L^∞(μ) into RBMO (μ) and from Hb (μ) into L1(μ). According to the interpolation theorem introduced by Tolsa, the LP(μ)-boundedness (1 〈 p 〈 ∞) is established for θ-type Calder6n-Zygmund operators. Via a sharp maximal operator, it is shown that commutators and multilinear commutators of θ-type CMderθn-Zygmundoperator with RBMO (μ) function are bounded on LP(μ) (1 〈 p 〈 ∞).
基金Supported by National Natural Science Foundation of China (Grant No. 10871025)
文摘Let (y, d, dλ) be (Rn, |·|,μ), where |·| is the Euclidean distance, μ is a nonnegative Radon measure on Rn satisfying the polynomial growth condition, or the Gauss measure metric space (Rn, |·|,dγ), or the space (S, d, p), where S - Rn×R+ is the (ax + b)-group, d is the left-invariant Riemannian metric and p is the right Haar measure on S with exponential growth. In this paper, the authors introduce and establish some properties of the atomic Hardy-type spaces {Xs(Y))0〈s≤∞ and the BM0-type spaces {BM0(y, s)}0〈s≤∞. Let Hi(Y) be the known atomic Hardy space and L01(y) the subspace of f ∈ L1(Y) with integral 0. The authors prove that the dual space of Xs(Y) is SM0(Y,s) when s∈ (0, ∞), Xs(Y) = H1(Y) when s ∈ (0, 1], and X∞(y) = L01(Y) (or L1(Y)). As applications, the authors show that if T is a linear operator bounded from H1 (Y) to L1 (Y) and from L1(y) to L1,∞(Y), then for all r ∈ (1, ∞) and s ∈ (r, ∞], T is bounded from Xr(y) to the Lorentz space L1,8(y), which applies to the Calderon-Zygmund operator on (Rn, |·|,μ), the imaginary powers of the 0rnstein-Uhlenbeck operator on (Rn, |·|,dγ) and the spectral operator associated with the spectral multiplier on (S, d, p). All these results generalize the corresponding results of Sweezy, Abu-Shammala and Torchinsky on Euclidean spaces.
基金Supported by the National Natural Science Foundation of China(No.10871025)
文摘Under the assumption that μ is a non-doubling measure on R^d which only satisfies the polynomial growth condition, the authors obtain the boundedness of the multilinear fractional integrals on Morrey spaces, weak-Morrey spaces and Lipschitz spaces associated with it, which, in the case when μ is the d-dimensional Lebesgue measure, also improve the known results.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 11171027, 11101339) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120003110003).
文摘Let μ be a nonnegative Radon measure on Rd which satisfies the polynomial growth condition that there exist positive constants Co and n ∈ (0,d) such that, for all x ∈ Rd and r 〉 0, μ(B(x, r))≤ Corn, where B(x, r) denotes the open ball centered at x and having radius r. In this paper, we show that, if μ(Rd) 〈∞, then the boundedness of a Calderdn-Zygmund operator T on L2(μ) is equivalent to that of T from the localized atomic Hardy space h1(μ) to L1,∞(μ) or from h1(μ) to L1(μ).
文摘Let μ be a Borel measure on R^d which may be non doubling. The only condition that μ must satisfy is μ(Q) ≤ col(Q)^n for any cube Q belong to R^d with sides parallel to the coordinate axes and for some fixed n with 0 〈 n ≤ d. The purpose of this paper is to obtain a boundedness property of fractional integrals in Hardy spaces H^1(μ).
文摘Introduction: COVID-19 is a pandemic disease caused by the coronavirus SARS-COV2 appeared in China in 2019. The aim of the study was to evaluate the practice of barrier measures against COVID-19 and to identify associated factors among diabetics followed at Departmental University Hospital Center Ouémé-Plateau, Benin, in 2021. Methods: This was a cross-sectional study conducted from June to August 2021, including diabetics aged 18 and over, hospitalized or received for medical visits in the department of medicine at the target hospital. Data were collected during an interview with each participant thanks to a questionnaire. “Good practice” was defined as regular practice of at least two of three barrier measures: hand washing, physical distancing and mask-wearing. Results: A total of 110 diabetics were included with a female predominance (55.5%) and a mean age of 57 ± 11.3 years. Among them, 89.1% washed their hands, 41.8% respected physical distancing and 12.7% wore a mask. The proportion of good practice was 47.3%. Only 5 practiced the three barrier measures. Only age group was associated with good practice. Conclusion: The study showed a low proportion of good practice of barrier measures against COVID-19 among diabetic people surveyed. It is important to continue the action for COVID-19 prevention among diabetic people in the targeted hospital and in other hospitals in Benin.
基金supported by the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZDRW-08)the Sichuan Science and Technology Program(Grant No.2022JDR0209).
文摘Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the specific disasterreduction effects of these measures and their economic,social and ecological benefits is yet to be performed.The western region of Sichuan Province frequentlysuffers from geohazards such as debris flow, and thegovernment has adopted many mitigation measures.This study assessed the benefits of debris flowmitigation measures and identified the key influencingfactors via a field-based study conducted in 81 villagesin western Sichuan province, China. A framework forthe evaluation of the benefits of rural debris flowmitigation measures was constructed andquantitatively evaluated using a survey. Snowballsampling was performed to recruit 81 village leadersand 468 farmers. The results showed that managementand engineering measures were the main methodsused to mitigate debris flow;ecological measures wereauxiliary. The average satisfaction scores of farmers forthese three types of measures were 4.07, 3.90, and 3.56,respectively (as measured on a five-point Likert scale).In contrast, in terms of the benefits of these mitigationmeasures, only a small proportion of villages (11.11%)obtained a high level of comprehensive benefits fromthe debris flow mitigation measures, while the majority(88.89%) received medium to low-level benefits. Toimprove this situation, we further studied and foundthat the main factors that restricted villages fromachieving high-level comprehensive benefits were theunpredictable nature of debris flows, labour forceoutflow and remoteness. Effective control measures, agood economic environment and strong governmentassistance were reported as crucial factors forimproving these comprehensive benefits. This studyprovides socio-scientific references for decisionmakingon rural debris flow mitigation measures while keeping villages at the centre of economic development.
文摘Context: COVID-19 can spread rapidly in haemodialysis centres, leading to fatal outcomes. Implementing physical measures is crucial in limiting the spread of infection. Aims: To assess adherence to physical measures against SARS-Cov2 in haemodialysis patients. Methods and Material: From 13 to 19 July 2021, we administered the questionnaire to haemodialysis patients during or immediately after the dialysis session. The dependent variables were adherence to wearing masks, hand washing outside the dialysis centre, social distancing of at least 1.5 meters, and cough and sneeze hygiene. Statistical Analysis Used: Data were analyzed using Epi info software;descriptive statistics were presented as mean, headcount, and percentage;related factors were determined by multi-logistic regression. The significance level was 5%. The Health Research Ethics Committee approved the research protocol. Results: 142 patients were included (mean age: 42.5 ± 14 years). Wearing masks, hand-washing, social distancing, and coughing and sneezing hygiene were observed by 88%, 75%, 47%, and 60% of patients, respectively. Conclusion: Wearing masks was the most respected physical measure, while social distancing was the least respected.
文摘This research focuses on the effects of migration on the TB infection rate and its prevention in Saudi Arabia, which has a large number of expatriates from TB-affected countries. Despite, based on the current global statistics of TB occurrence, it is evident that the national incidence of TB has reduced from 10.55 per 100,000 in 2015 to 8.36 per 100,000 in 2019;despite this, there are still some difficulties because migrants bring new strains of Mycobacterium tuberculosis. Hindrances, including language barriers and perceived immigration status, hinder patients from seeking medical attention or doctors from diagnosing diseases. Each patient and each cultural group need special attention to public health, enhancing living circumstances, and health care support. Community participation, inclusion of TB control programs into functional healthcare facilities, and the functioning of TB programs need to be stressed to address TB issues. Considering the focus on social, economic, and cultural approaches, the country can make severe advancements in TB control and population protection. This holistic analysis is critical for a long-term effective strategy to combat TB in the Kingdom.
基金Supported by National Natural Science Foundation of China(Grant Nos.U2268210,52302474,52072249).
文摘Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.
文摘BACKGROUND Intravenous infusion is a common method of drug administration in clinical practice.Errors in any aspect of the infusion process,from the verification of medical orders,preparation of the drug solution,to infusion by nursing staff,may cause adverse infusion events.AIM To analyzed the value of improving nursing measures and enhancing nursing management to reduce the occurrence of adverse events in pediatric infusion.METHODS The clinical data of 130 children who received an infusion in the pediatric department of our hospital from May 2020 to May 2021 were analyzed and divided into two groups according to the differences in nursing measures and nursing management:65 patients in the control group received conventional nursing and nursing management interventions,while 65 patients in the observation group received improved nursing measure interventions and enhanced nursing management.The occurrence of adverse events,compliance of children,satisfaction of children’s families,and complaints regarding the transfusion treatment were recorded in both groups.RESULTS The incidence of fluid extravasation and infusion set dislodgement in the observation group were 3.08%and 1.54%,respectively,which were significantly lower than 12.31%and 13.85%in the control group(P<0.05),while repeated punctures and medication addition errors in the observation group were 3.08%and 0.00%,respectively,which were lower than 9.23%and 3.08%in the control group,but there was no significant difference(P>0.05).The compliance rate of children in the observation group was 98.46%(64/65),which was significantly higher than 87.69%(57/65)in the control group,and the satisfaction rate of children’s families was 96.92%(63/65),which was significantly higher than 86.15%(56/65)in the control group(P<0.05).The observation group did not receive any complaints from the child’s family,whereas the control group received four complaints,two of which were due to the crying of the child caused by repeated punctures,one due to the poor attitude of the nurse,and one due to medication addition errors,with a cumulative complaint rate of 6.15%.The cumulative complaint rate of the observation group was significantly lower than that of the control group(P<0.05).CONCLUSION Improving nursing measures and enhancing nursing management can reduce the incidence of fluid extravasation and infusion set dislodgement in pediatric patients,improve children’s compliance and satisfaction of their families,and reduce family complaints.