A rice low temperature-induced albino variant was determined by the recessive ltia1 and ltia2 genes.LTIA1 and LTIA2 encode highly conserved mini-ribonucleasesⅢlocated in chloroplasts and expressed in aerial parts of ...A rice low temperature-induced albino variant was determined by the recessive ltia1 and ltia2 genes.LTIA1 and LTIA2 encode highly conserved mini-ribonucleasesⅢlocated in chloroplasts and expressed in aerial parts of the plant.At low temperature,LTIA1 and LTIA2 redundantly affect chlorophyll levels,non-photochemical quenching,photosynthetic quantum yield of PSⅡand seedling growth.LTIA1 and LTIA2 proteins are involved in splicing of atp F and the biogenesis of 16S and 23S rRNA in chloroplasts.Presence/absence variation of LTIA1,the ancestral copy,was found only in japonica but that of LTIA2 in all rice subgroups.Accessions with LTIA2 presence tended to be distributed more remote from the equator compared to those with LTIA2 absence.LTIA2 duplicated from LTIA1 at the early stage of divergence of the AA genome Oryza species but deleted againin O.nivara.In cultivated rice,absence of LTIA2 is derived from O.nivara.LTIA1 absence occurred more recently in japonica.展开更多
With the rapid development of immersive multimedia technologies,360-degree video services have quickly gained popularity and how to ensure sufficient spatial presence of end users when viewing 360-degree videos become...With the rapid development of immersive multimedia technologies,360-degree video services have quickly gained popularity and how to ensure sufficient spatial presence of end users when viewing 360-degree videos becomes a new challenge.In this regard,accurately acquiring users’sense of spatial presence is of fundamental importance for video service providers to improve their service quality.Unfortunately,there is no efficient evaluation model so far for measuring the sense of spatial presence for 360-degree videos.In this paper,we first design an assessment framework to clarify the influencing factors of spatial presence.Related parameters of 360-degree videos and headmounted display devices are both considered in this framework.Well-designed subjective experiments are then conducted to investigate the impact of various influencing factors on the sense of presence.Based on the subjective ratings,we propose a spatial presence assessment model that can be easily deployed in 360-degree video applications.To the best of our knowledge,this is the first attempt in literature to establish a quantitative spatial presence assessment model by using technical parameters that are easily extracted.Experimental results demonstrate that the proposed model can reliably predict the sense of spatial presence.展开更多
The analysis of company data useful for economic decisions,if not interpreted in an overall view of the company situation,can lead to wrong conclusions.This is the case when a company has to choose between several sal...The analysis of company data useful for economic decisions,if not interpreted in an overall view of the company situation,can lead to wrong conclusions.This is the case when a company has to choose between several sales options for one or more products in the presence of a limiting factor.The continuation of the investigation often denies the initial analysis.Not everything is as it appears,therefore,at the beginning of the deepening of the data useful for economic decisions.As it is well known,the choices of profitability concerning the planning of the sale of company products take place,at least in the majority of cases,through the determination of the contribution margin,i.e.the profitability margin connected to the individual goods/services sold by the companies(selling price net of variable costs).The contribution margin can be determined with four objectives:(1)Determination of the yield of the single product,net of variable costs only.In this case,the margin defines unitary,from net product yield to unitary contribution margin.(2)Determination of the return on total sales of an individual product,net of variable costs.In this hypothesis,reference is made to the first level(or gross)contribution margin.(3)Determination of the ability of the individual product to contribute to the coverage of fixed costs common to the company.This margin is determined net of special product variable and fixed costs.This aggregate is defined as a Level II(or semi-gross)margin.(4)Determination of the useful value in the planning choices in case of presence of scarce productive factors.In this case,it must identify the so-called unitary margin for low factor.Here we will only deal with the problem of the use of the contribution margin in the presence of rare factors.To complete the analysis,below are some very brief considerations regarding,respectively,the unitary,level I,and level II contribution margin in order to better understand where the problem of the most convenient choice of income is located in the event of the presence of rare production factors,especially in an environment characterized by a plurality of sales options.展开更多
The following are our views regarding the“letter to the editor”(Helicobacter is preserved in yeast vacuoles!Does Koch’s postulates confirm it?)by Alipour and Gaeini,and the response“letter to the editor”(Candida ...The following are our views regarding the“letter to the editor”(Helicobacter is preserved in yeast vacuoles!Does Koch’s postulates confirm it?)by Alipour and Gaeini,and the response“letter to the editor”(Candida accommodates nonculturable Helicobacter pylori in its vacuole-Koch’s postulates aren’t applicable)by Siavoshi and Saniee.Alipour and Gaeini rejected the methods,results,discussion,and conclusions summarized in a review article by Siavoshi and Saniee.The present article reviews and discusses evidence on the evolutionary adaptation of Helicobacter pylori(H.pylori)to thrive in Candida cell vacuoles and concludes that Candida could act as a Trojan horse,transporting potentially infectious H.pylori into the stomach of humans.展开更多
The high-quality development of tourism aims to improve tourists'sense of well-being and fulfillment.The improvement of tourists'sense of well-being will not only enable tourists to obtain positive emotional e...The high-quality development of tourism aims to improve tourists'sense of well-being and fulfillment.The improvement of tourists'sense of well-being will not only enable tourists to obtain positive emotional experiences but is also an important way to improve their quality of life.However,the existing research has not yet reached a clear conclusion on how tourists'sense of well-being is formed,whether tourists'sense of well-being will spill over(i.e.,knowledge sharing)after tourists obtain it,and whether the destination familiarity brought by the spillover of sense of well-being(i.e.,knowledge sharing)will affect other tourists.Therefore,based on the experience marketing theory and the embodiment theory,this paper empirically examines the formation and spillover effect of tourists'sense of well-being through structural equation modeling(SEM).The research shows that:(a)Subject presence has a positive effect on tourists'sense of well-being,which further promotes knowledge sharing and realizes the spillover of tourists'sense of well-being,and tourists'sense of well-being plays a mediating role between subject presence and knowledge sharing;(b)Destination familiarity resulting from the spillover of sense of wellbeing(i.e.,knowledge sharing)plays a negative moderating role in the positive impact of subject presence on tourists'sense of well-being.This paper not only expands the boundaries of research on tourists'sense of well-being and embodiment theory to some extent but also provides theoretical support and countermeasures for the high-quality development of China's tourism and even service industry.展开更多
Over the past few years,China’s higher education institutions have experienced remarkable growth in online teaching.However,it remains uncertain whether and how the sense of presence perceived by students affects the...Over the past few years,China’s higher education institutions have experienced remarkable growth in online teaching.However,it remains uncertain whether and how the sense of presence perceived by students affects their online learning outcomes when teachers use online teaching media for communication.This sense specifically pertains to the extent to which students perceive themselves as“real persons”and establish connections with others.Therefore,this study constructs a conceptual model elucidating the impact of presence on students’online learning outcomes and empirically examines the mechanism through which three types of presence influence students’online learning.The test results of the structural equation modeling(SEM)indicate that:(a)teaching presence,social presence,and cognitive presence all exhibit significantly positive outcomes on students’online learning outcomes;(b)these three types of presence can also indirectly and positively influence students’online learning outcomes through the mediating effect of flow experience and learning satisfaction;and(c)flow experience and learning satisfaction play a sequential mediating role in the process by which presence impacts students’online learning outcomes.We hope that the relevant research findings may contribute to unveiling the“black box”of the impact of presence on students’online learning outcomes and offer valuable insights for college educators to overcome online teaching constraints and enhance online teaching quality.展开更多
We extend Bespalov-Talanov (B-T) theory on small-scale self-focusing (SSSF) to include vector effect of a very narrow intense laser beam with application of the vector self-focusing model. The gain spectrum for pertur...We extend Bespalov-Talanov (B-T) theory on small-scale self-focusing (SSSF) to include vector effect of a very narrow intense laser beam with application of the vector self-focusing model. The gain spectrum for perturbations is obtained by using the standard linear instability analysis. It is shown that the influence on SSSF of vector effect is closely related to the beam width. For a very narrow beam, the role played by vector effect becomes significant, it reduces the fastest growing frequency and the maximum growth rate, and shortens the frequency range for perturbation growing, and thus deviates the gain spectrum from that of B-T theory.展开更多
Antibodies to the ubiquitous group of stress proteins known as heat shock proteins (Hsps) have been found to be associated with a number of diseases in humans. Hsps are known to be induced by certain xenobiotics, some...Antibodies to the ubiquitous group of stress proteins known as heat shock proteins (Hsps) have been found to be associated with a number of diseases in humans. Hsps are known to be induced by certain xenobiotics, some of which are common in the working environment. The biological significance of the presence of such autoantibodies is presently unclear. In the present study, we used immunoblotting to investigate the presence of antibodies against the different stress proteins, Hsp27, Hsp60, Hsp71, Hse (heat shock cognate ) 73 and Hsp89a and D in groups of workers exposed to high temperature or carbon monoxide. These data were related to a detailed clinical evaluation and to various laboratory measurements including electrocardiogram (ECG), B echogram, white blood cell counts and typing, the activity of alanine aminotransferase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) and lymphocyte DNA damage. Antibodies to Hsp27 and Hsp71 were found more frequently in the high temperature and carbon monoxide-exposed groups than in controls (P (0.05 ). The carbon monoxide-exposed group showed the highest incidence of anti-Hsp antibodies. Anti-Hsp60 antibodies were only detected in workers exposed to high temperature or carbon monoxide. The percentage of workers with abnormal ECG, B echogram changes and displaying hepatitis B antigen (HBsAg ) was higher in the carbon monoxide group than in the control group (P<0.05 ).There was a significant inerease in the activity of ALT in the high temperature and carbon monoxide groups and in the activities of ACP and ALP in the carbon monoxide group (P<0.05 ). The extent of DNA damage measured in lymphoeytes was higher in workers from the high temperature and carbon monoxide-cxposed groups. We suggest that the increased frequeney of antibodies to Hsps is the result of these damages, of the release of denatured Hsps and of a decrease in the phagocytic ability of macrophages in these workers. The data gathered in the present study show a statistical relation between the occurrence of antibodies against Hsps and the frequency of health problems in workers and suggest a potential role for the antibodies as useful biomarkers to assess whether workers are experieneing environmental stress展开更多
The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K_sS_sO_s-water in the presence of Barium Sulfate(BS)powder was investigated under varied conditions within the range of BS powder quantity...The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K_sS_sO_s-water in the presence of Barium Sulfate(BS)powder was investigated under varied conditions within the range of BS powder quantity,initiator concentration and reaction temperature.Experimental results showed that the rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of the initiator concentration.There is a linear relationship of 2/3-power for the conversion and time.A process for the polymerization is propose to explain the experimental results.展开更多
Evolution of spatial distribution of charged particulates under the action of an external force is investigated. It is found that starting from a homogeneous Maxwellian distribution of particulates, clusters can form ...Evolution of spatial distribution of charged particulates under the action of an external force is investigated. It is found that starting from a homogeneous Maxwellian distribution of particulates, clusters can form and aggregate. The evolution process, as well as the asymptotic number and configuration of the clusters formed, depends strongly on the strength of the external force. The particulates in most of the final clusters are in the crystal state, as can also be deduced from the corresponding velocity and auto-correlation functions.展开更多
BACKGROUND Surgical intervention is usually a traumatic event that causes stress and anxiety in the pediatric patient and the family environment.To reduce the harmful effects of presurgical anxiety,parental presence d...BACKGROUND Surgical intervention is usually a traumatic event that causes stress and anxiety in the pediatric patient and the family environment.To reduce the harmful effects of presurgical anxiety,parental presence during induction of anesthesia(PPIA)is one of the more notable interventions used in medical centers.However,data on this measure are difficult to evaluate and often face resistance from healthcare staff.AIM To analyze the perception of the healthcare workers after the implementation of a PPIA program.METHODS A survey was developed and sent by email to all the healthcare staff working in the children’s area of a tertiary hospital.It consisted of 14 items divided into positive aspects of PPIA and negative aspects of PPIA evaluated with the use of a Likert scale(1 to 5).The demographics of the respondents were included in the data collected.The answers to the questions were interpreted through the Net Promoter Score(NPS).The statistical analysis compared the differences in the responses to each question of the survey made by the different groups of health personnel included.RESULTS A total of 141 surveys were sent out,with a response rate of 69%.Of the total number of responses,68%were from women and 32%from men.The average age of the participants was 42.3±10.6 years.As for the positive questions about the PPIA,83%had an NPS>50,and only one had a score between 0 and 50,which means that the quality of the service was rated as excellent or good by 100%of the respondents.On the other hand,100%of the negative questions about the PPIA had a negative NPS.Responses to the question“PPIA increases patient safety”were significantly different(P=0.037),with a lower percentage of pediatric surgeons(70%)thinking that PPIA increased patient safety,compared with anesthesiologists(90%),nursing(92%),and other medical personnel(96%).CONCLUSION The personnel who participated in the PPIA program at our center were in favor of implementation.There were no validated arguments to support worker resistance to the development of the PPIA.展开更多
We demonstrate theoretically the anisotropic quantum transport of electrons through an electric field on monolayer and multilayer phosphorene. Using the long-wavelength Hamiltonian with continuum approximation, we fin...We demonstrate theoretically the anisotropic quantum transport of electrons through an electric field on monolayer and multilayer phosphorene. Using the long-wavelength Hamiltonian with continuum approximation, we find that the transmission probability for transport through an electric field is an oscillating function of incident angle, electric field intensity, as well as the incident energy of electrons. By tuning the electric field intensity and incident angle, the channels can be transited from opaque to transparent. The conductance through the quantum waveguides depends sensitively on the transport direction because of the anisotropic effective mass, and the anisotropy of the conductance can be tuned by the electric field intensity and the number of layers. These behaviors provide us an efficient way to control the transport of phosphorene-based microstructures.展开更多
Background Virtual-reality(VR)fusion techniques have become increasingly popular in recent years,and several previous studies have applied them to laboratory education.However,without a basis for evaluating the effect...Background Virtual-reality(VR)fusion techniques have become increasingly popular in recent years,and several previous studies have applied them to laboratory education.However,without a basis for evaluating the effects of virtual-real fusion on VR in education,many developers have chosen to abandon this expensive and complex set of techniques.Methods In this study,we experimentally investigate the effects of virtual-real fusion on immersion,presence,and learning performance.Each participant was randomly assigned to one of three conditions:a PC environment(PCE)operated by mouse;a VR environment(VRE)operated by controllers;or a VR environment running virtual-real fusion(VR VRFE),operated by real hands.Results The analysis of variance(ANOVA)and t-test results for presence and self-efficacy show significant differences between the PCE*VR-VRFE condition pair.Furthermore,the results show significant differences in the intrinsic value of learning performance for pairs PCE*VR VRFE and VRE*VR-VRFE,and a marginally significant difference was found for the immersion group.Conclusions The results suggest that virtual-real fusion can offer improved immersion,presence,and self efficacy compared to traditional PC environments,as well as a better intrinsic value of learning performance compared to both PC and VR environments.The results also suggest that virtual-real fusion offers a lower sense of presence compared to traditional VR environments.展开更多
Based on the time-convolutionless master-equation approach, the entropic uncertainty in the presence of quantum memory is investigated for a two-atom system in two dissipative cavities. We find that the entropic uncer...Based on the time-convolutionless master-equation approach, the entropic uncertainty in the presence of quantum memory is investigated for a two-atom system in two dissipative cavities. We find that the entropic uncertainty can be controlled by the non-Markovian effect and the atom-cavity coupling. The results show that increasing the atom-cavity coupling can enlarge the oscillating frequencies of the entropic uncertainty and can decrease the minimal value of the entropic uncertainty. Enhancing the non-Markovian effect can reduce the minimal value of the entropic uncertainty. In particular, if the atom-cavity coupling or the non-Markovian effect is very strong, the entropic uncertainty will be very dose to zero at certain time points, thus Bob can minimize his uncertainty about Alice's measurement outcomes,展开更多
Using bis(p-methoxyphenyl)telluroxide(BMPTO)as the catalyst, phenylsulphonyl acetonitrile condensed easily with aromatic aldehydes at room temperature to give -cyano- ,β-unsaturated sulphones in high yields.
To investigate soapless emulsion copolymerization in the presence of a solid phase, copolymerization experiments were carried out for the styrene-butyl acrylate-K_2S_2O_8-water system by using barium sulfate powder,wh...To investigate soapless emulsion copolymerization in the presence of a solid phase, copolymerization experiments were carried out for the styrene-butyl acrylate-K_2S_2O_8-water system by using barium sulfate powder,which is assumed to be chemically inert.Reaction conditions were varied with respect to barium sulfate powder quantity,initiator concen- tration and temperature.These factors were investigated with respect to the effect on reaction rate and conversion,polymer particle number and diameter,and latex stability.展开更多
Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is...Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is often difficult to distinguish between algal blooms and aquatic vegetation due to their similar spectral characteristics. In this paper, we used modified vegetation presence frequency index(VPF) based on Moderate-resolution Imaging Spectroradiometer(MODIS) imagery to distinguish algal blooms from aquatic vegetation, and analyzed the spatial and temporal variations of algal blooms and aquatic vegetation from a phenological perspective for five large natural lakes with frequent algal bloom outbreaks in China from 2019 to 2020. We simplified the VPF method to make it with a higher spatial transferability so that it could be applied to other lakes in different climatic zones. Through accuracy validation, we found that the modified VPF method can effectively distinguish between algal blooms and aquatic vegetation, and the results vary from lake to lake. The highest accuracy of 97% was achieved in Hulun Lake, where the frequency of algal outbreaks is low and the extent of aquatic vegetation is stable, while the lowest accuracy of 76% was achieved in Dianchi Lake, which is rainy in summer and the lake is small. Analyses suggests that the time period when algal blooms occur most frequently might not coincide with that when they have the largest area. However, in most cases these two are close in terms of time period. The modified VPF method has a broad scope of application, is easy to implement, and has a high practical value. Furthermore, the method could be established using only a small amount of measured data, which is useful for water quality monitoring on large spatial scales.展开更多
Tb(111) and Ca(11) ion equilibria in the presence of glutamic acid and glutamine were studied by potentiometric titration at 37'C and an ionic strength of 0. 15mol/L(NaCl) .The stability constants for Tb(111) and ...Tb(111) and Ca(11) ion equilibria in the presence of glutamic acid and glutamine were studied by potentiometric titration at 37'C and an ionic strength of 0. 15mol/L(NaCl) .The stability constants for Tb(111) and Ca(11)complexes in the systems were obtained. The species and their distribution in the systems were discussed.展开更多
Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ter...Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ternary complex becomes more stable than before. For analytical application, the derivative spectrofluorimetric method has high sensitivity and the effect of foreign ions is very low. The optimum conditions were obtained. The calibration graph is linear over 5~100μg/mL.展开更多
基金supported by Zhejiang Provincial Natural Science Foundation of China (LD24C130002)Scientific Research Foundation of China Jiliang University。
文摘A rice low temperature-induced albino variant was determined by the recessive ltia1 and ltia2 genes.LTIA1 and LTIA2 encode highly conserved mini-ribonucleasesⅢlocated in chloroplasts and expressed in aerial parts of the plant.At low temperature,LTIA1 and LTIA2 redundantly affect chlorophyll levels,non-photochemical quenching,photosynthetic quantum yield of PSⅡand seedling growth.LTIA1 and LTIA2 proteins are involved in splicing of atp F and the biogenesis of 16S and 23S rRNA in chloroplasts.Presence/absence variation of LTIA1,the ancestral copy,was found only in japonica but that of LTIA2 in all rice subgroups.Accessions with LTIA2 presence tended to be distributed more remote from the equator compared to those with LTIA2 absence.LTIA2 duplicated from LTIA1 at the early stage of divergence of the AA genome Oryza species but deleted againin O.nivara.In cultivated rice,absence of LTIA2 is derived from O.nivara.LTIA1 absence occurred more recently in japonica.
基金supported in part by ZTE Industry⁃University⁃Institute Coop⁃eration Funds.
文摘With the rapid development of immersive multimedia technologies,360-degree video services have quickly gained popularity and how to ensure sufficient spatial presence of end users when viewing 360-degree videos becomes a new challenge.In this regard,accurately acquiring users’sense of spatial presence is of fundamental importance for video service providers to improve their service quality.Unfortunately,there is no efficient evaluation model so far for measuring the sense of spatial presence for 360-degree videos.In this paper,we first design an assessment framework to clarify the influencing factors of spatial presence.Related parameters of 360-degree videos and headmounted display devices are both considered in this framework.Well-designed subjective experiments are then conducted to investigate the impact of various influencing factors on the sense of presence.Based on the subjective ratings,we propose a spatial presence assessment model that can be easily deployed in 360-degree video applications.To the best of our knowledge,this is the first attempt in literature to establish a quantitative spatial presence assessment model by using technical parameters that are easily extracted.Experimental results demonstrate that the proposed model can reliably predict the sense of spatial presence.
文摘The analysis of company data useful for economic decisions,if not interpreted in an overall view of the company situation,can lead to wrong conclusions.This is the case when a company has to choose between several sales options for one or more products in the presence of a limiting factor.The continuation of the investigation often denies the initial analysis.Not everything is as it appears,therefore,at the beginning of the deepening of the data useful for economic decisions.As it is well known,the choices of profitability concerning the planning of the sale of company products take place,at least in the majority of cases,through the determination of the contribution margin,i.e.the profitability margin connected to the individual goods/services sold by the companies(selling price net of variable costs).The contribution margin can be determined with four objectives:(1)Determination of the yield of the single product,net of variable costs only.In this case,the margin defines unitary,from net product yield to unitary contribution margin.(2)Determination of the return on total sales of an individual product,net of variable costs.In this hypothesis,reference is made to the first level(or gross)contribution margin.(3)Determination of the ability of the individual product to contribute to the coverage of fixed costs common to the company.This margin is determined net of special product variable and fixed costs.This aggregate is defined as a Level II(or semi-gross)margin.(4)Determination of the useful value in the planning choices in case of presence of scarce productive factors.In this case,it must identify the so-called unitary margin for low factor.Here we will only deal with the problem of the use of the contribution margin in the presence of rare factors.To complete the analysis,below are some very brief considerations regarding,respectively,the unitary,level I,and level II contribution margin in order to better understand where the problem of the most convenient choice of income is located in the event of the presence of rare production factors,especially in an environment characterized by a plurality of sales options.
基金Supported by the National Natural Science Foundation of China,No.82260402Basic Research Program of Guizhou Science and Technology Plan,No.ZK[2022]341Foundation of Key Laboratory of Education Department of Guizhou province,No.[2022]019.
文摘The following are our views regarding the“letter to the editor”(Helicobacter is preserved in yeast vacuoles!Does Koch’s postulates confirm it?)by Alipour and Gaeini,and the response“letter to the editor”(Candida accommodates nonculturable Helicobacter pylori in its vacuole-Koch’s postulates aren’t applicable)by Siavoshi and Saniee.Alipour and Gaeini rejected the methods,results,discussion,and conclusions summarized in a review article by Siavoshi and Saniee.The present article reviews and discusses evidence on the evolutionary adaptation of Helicobacter pylori(H.pylori)to thrive in Candida cell vacuoles and concludes that Candida could act as a Trojan horse,transporting potentially infectious H.pylori into the stomach of humans.
基金supported by the Sichuan Social Science Planning Project (General Project)“Research on the Development of Rural Tourism Sharing Economy in Sichuan from the Perspective of Rural Revitalization Strategy and All-for-one Tourism” (SC20B133)the Humanities and Social Sciences Research Special Fund Cultivation Project (2022-2023RW021)of Southwest Petroleum University。
文摘The high-quality development of tourism aims to improve tourists'sense of well-being and fulfillment.The improvement of tourists'sense of well-being will not only enable tourists to obtain positive emotional experiences but is also an important way to improve their quality of life.However,the existing research has not yet reached a clear conclusion on how tourists'sense of well-being is formed,whether tourists'sense of well-being will spill over(i.e.,knowledge sharing)after tourists obtain it,and whether the destination familiarity brought by the spillover of sense of well-being(i.e.,knowledge sharing)will affect other tourists.Therefore,based on the experience marketing theory and the embodiment theory,this paper empirically examines the formation and spillover effect of tourists'sense of well-being through structural equation modeling(SEM).The research shows that:(a)Subject presence has a positive effect on tourists'sense of well-being,which further promotes knowledge sharing and realizes the spillover of tourists'sense of well-being,and tourists'sense of well-being plays a mediating role between subject presence and knowledge sharing;(b)Destination familiarity resulting from the spillover of sense of wellbeing(i.e.,knowledge sharing)plays a negative moderating role in the positive impact of subject presence on tourists'sense of well-being.This paper not only expands the boundaries of research on tourists'sense of well-being and embodiment theory to some extent but also provides theoretical support and countermeasures for the high-quality development of China's tourism and even service industry.
基金the project“Research on the Evaluation Mechanism of College Ideological and Political Education:A Perspective on Teacher-Student Development,”funded by Zhejiang Provincial College Ideological and Political Education Research Project.
文摘Over the past few years,China’s higher education institutions have experienced remarkable growth in online teaching.However,it remains uncertain whether and how the sense of presence perceived by students affects their online learning outcomes when teachers use online teaching media for communication.This sense specifically pertains to the extent to which students perceive themselves as“real persons”and establish connections with others.Therefore,this study constructs a conceptual model elucidating the impact of presence on students’online learning outcomes and empirically examines the mechanism through which three types of presence influence students’online learning.The test results of the structural equation modeling(SEM)indicate that:(a)teaching presence,social presence,and cognitive presence all exhibit significantly positive outcomes on students’online learning outcomes;(b)these three types of presence can also indirectly and positively influence students’online learning outcomes through the mediating effect of flow experience and learning satisfaction;and(c)flow experience and learning satisfaction play a sequential mediating role in the process by which presence impacts students’online learning outcomes.We hope that the relevant research findings may contribute to unveiling the“black box”of the impact of presence on students’online learning outcomes and offer valuable insights for college educators to overcome online teaching constraints and enhance online teaching quality.
基金Supported by the High Technology Research and Development Program of China(Grant No.863-416-5).
文摘We extend Bespalov-Talanov (B-T) theory on small-scale self-focusing (SSSF) to include vector effect of a very narrow intense laser beam with application of the vector self-focusing model. The gain spectrum for perturbations is obtained by using the standard linear instability analysis. It is shown that the influence on SSSF of vector effect is closely related to the beam width. For a very narrow beam, the role played by vector effect becomes significant, it reduces the fastest growing frequency and the maximum growth rate, and shortens the frequency range for perturbation growing, and thus deviates the gain spectrum from that of B-T theory.
文摘Antibodies to the ubiquitous group of stress proteins known as heat shock proteins (Hsps) have been found to be associated with a number of diseases in humans. Hsps are known to be induced by certain xenobiotics, some of which are common in the working environment. The biological significance of the presence of such autoantibodies is presently unclear. In the present study, we used immunoblotting to investigate the presence of antibodies against the different stress proteins, Hsp27, Hsp60, Hsp71, Hse (heat shock cognate ) 73 and Hsp89a and D in groups of workers exposed to high temperature or carbon monoxide. These data were related to a detailed clinical evaluation and to various laboratory measurements including electrocardiogram (ECG), B echogram, white blood cell counts and typing, the activity of alanine aminotransferase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) and lymphocyte DNA damage. Antibodies to Hsp27 and Hsp71 were found more frequently in the high temperature and carbon monoxide-exposed groups than in controls (P (0.05 ). The carbon monoxide-exposed group showed the highest incidence of anti-Hsp antibodies. Anti-Hsp60 antibodies were only detected in workers exposed to high temperature or carbon monoxide. The percentage of workers with abnormal ECG, B echogram changes and displaying hepatitis B antigen (HBsAg ) was higher in the carbon monoxide group than in the control group (P<0.05 ).There was a significant inerease in the activity of ALT in the high temperature and carbon monoxide groups and in the activities of ACP and ALP in the carbon monoxide group (P<0.05 ). The extent of DNA damage measured in lymphoeytes was higher in workers from the high temperature and carbon monoxide-cxposed groups. We suggest that the increased frequeney of antibodies to Hsps is the result of these damages, of the release of denatured Hsps and of a decrease in the phagocytic ability of macrophages in these workers. The data gathered in the present study show a statistical relation between the occurrence of antibodies against Hsps and the frequency of health problems in workers and suggest a potential role for the antibodies as useful biomarkers to assess whether workers are experieneing environmental stress
文摘The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K_sS_sO_s-water in the presence of Barium Sulfate(BS)powder was investigated under varied conditions within the range of BS powder quantity,initiator concentration and reaction temperature.Experimental results showed that the rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of the initiator concentration.There is a linear relationship of 2/3-power for the conversion and time.A process for the polymerization is propose to explain the experimental results.
基金Supported by the Natural Science Foundation of Zhejiang Province under Grant No LY15A050001the National Natural Science Foundation of China under Grant Nos 11247007 and 11374262the Open Fund of the State Key Laboratory of High-Field Laser Physics at SIOM
文摘Evolution of spatial distribution of charged particulates under the action of an external force is investigated. It is found that starting from a homogeneous Maxwellian distribution of particulates, clusters can form and aggregate. The evolution process, as well as the asymptotic number and configuration of the clusters formed, depends strongly on the strength of the external force. The particulates in most of the final clusters are in the crystal state, as can also be deduced from the corresponding velocity and auto-correlation functions.
文摘BACKGROUND Surgical intervention is usually a traumatic event that causes stress and anxiety in the pediatric patient and the family environment.To reduce the harmful effects of presurgical anxiety,parental presence during induction of anesthesia(PPIA)is one of the more notable interventions used in medical centers.However,data on this measure are difficult to evaluate and often face resistance from healthcare staff.AIM To analyze the perception of the healthcare workers after the implementation of a PPIA program.METHODS A survey was developed and sent by email to all the healthcare staff working in the children’s area of a tertiary hospital.It consisted of 14 items divided into positive aspects of PPIA and negative aspects of PPIA evaluated with the use of a Likert scale(1 to 5).The demographics of the respondents were included in the data collected.The answers to the questions were interpreted through the Net Promoter Score(NPS).The statistical analysis compared the differences in the responses to each question of the survey made by the different groups of health personnel included.RESULTS A total of 141 surveys were sent out,with a response rate of 69%.Of the total number of responses,68%were from women and 32%from men.The average age of the participants was 42.3±10.6 years.As for the positive questions about the PPIA,83%had an NPS>50,and only one had a score between 0 and 50,which means that the quality of the service was rated as excellent or good by 100%of the respondents.On the other hand,100%of the negative questions about the PPIA had a negative NPS.Responses to the question“PPIA increases patient safety”were significantly different(P=0.037),with a lower percentage of pediatric surgeons(70%)thinking that PPIA increased patient safety,compared with anesthesiologists(90%),nursing(92%),and other medical personnel(96%).CONCLUSION The personnel who participated in the PPIA program at our center were in favor of implementation.There were no validated arguments to support worker resistance to the development of the PPIA.
基金Supported by the National Natural Science Foundation of China under Grant No 11374002the Scientific Research Fund of Hunan Provincial Education Department under Grant No 17A001the Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering of Changsha University of Science and Technology
文摘We demonstrate theoretically the anisotropic quantum transport of electrons through an electric field on monolayer and multilayer phosphorene. Using the long-wavelength Hamiltonian with continuum approximation, we find that the transmission probability for transport through an electric field is an oscillating function of incident angle, electric field intensity, as well as the incident energy of electrons. By tuning the electric field intensity and incident angle, the channels can be transited from opaque to transparent. The conductance through the quantum waveguides depends sensitively on the transport direction because of the anisotropic effective mass, and the anisotropy of the conductance can be tuned by the electric field intensity and the number of layers. These behaviors provide us an efficient way to control the transport of phosphorene-based microstructures.
基金the National Key Research and Development Program of China(2018YFB1004902)the National Natural Science Foundation of China(61772329,61373085)。
文摘Background Virtual-reality(VR)fusion techniques have become increasingly popular in recent years,and several previous studies have applied them to laboratory education.However,without a basis for evaluating the effects of virtual-real fusion on VR in education,many developers have chosen to abandon this expensive and complex set of techniques.Methods In this study,we experimentally investigate the effects of virtual-real fusion on immersion,presence,and learning performance.Each participant was randomly assigned to one of three conditions:a PC environment(PCE)operated by mouse;a VR environment(VRE)operated by controllers;or a VR environment running virtual-real fusion(VR VRFE),operated by real hands.Results The analysis of variance(ANOVA)and t-test results for presence and self-efficacy show significant differences between the PCE*VR-VRFE condition pair.Furthermore,the results show significant differences in the intrinsic value of learning performance for pairs PCE*VR VRFE and VRE*VR-VRFE,and a marginally significant difference was found for the immersion group.Conclusions The results suggest that virtual-real fusion can offer improved immersion,presence,and self efficacy compared to traditional PC environments,as well as a better intrinsic value of learning performance compared to both PC and VR environments.The results also suggest that virtual-real fusion offers a lower sense of presence compared to traditional VR environments.
基金Supported by the Science and Technology Plan of Hunan Province under Grant No 2010FJ3148the National Natural Science Foundation of China under Grant No 11374096the Doctoral Science Foundation of Hunan Normal University
文摘Based on the time-convolutionless master-equation approach, the entropic uncertainty in the presence of quantum memory is investigated for a two-atom system in two dissipative cavities. We find that the entropic uncertainty can be controlled by the non-Markovian effect and the atom-cavity coupling. The results show that increasing the atom-cavity coupling can enlarge the oscillating frequencies of the entropic uncertainty and can decrease the minimal value of the entropic uncertainty. Enhancing the non-Markovian effect can reduce the minimal value of the entropic uncertainty. In particular, if the atom-cavity coupling or the non-Markovian effect is very strong, the entropic uncertainty will be very dose to zero at certain time points, thus Bob can minimize his uncertainty about Alice's measurement outcomes,
文摘Using bis(p-methoxyphenyl)telluroxide(BMPTO)as the catalyst, phenylsulphonyl acetonitrile condensed easily with aromatic aldehydes at room temperature to give -cyano- ,β-unsaturated sulphones in high yields.
文摘To investigate soapless emulsion copolymerization in the presence of a solid phase, copolymerization experiments were carried out for the styrene-butyl acrylate-K_2S_2O_8-water system by using barium sulfate powder,which is assumed to be chemically inert.Reaction conditions were varied with respect to barium sulfate powder quantity,initiator concen- tration and temperature.These factors were investigated with respect to the effect on reaction rate and conversion,polymer particle number and diameter,and latex stability.
基金Under the auspices of National Key Research and Development Project of China (No. 2021YFB3901101)National Natural Science Foundation of China (No. 41971322, 42071336, 42001311, 41730104)+2 种基金Jilin Provincial Science and Technology Development Project (No. 20180519021JH)Youth Innovation Promotion Association of Chinese Academy of Sciences (No. 2020234)China Postdoctoral Science Foundation (No. 2020M681057)。
文摘Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is often difficult to distinguish between algal blooms and aquatic vegetation due to their similar spectral characteristics. In this paper, we used modified vegetation presence frequency index(VPF) based on Moderate-resolution Imaging Spectroradiometer(MODIS) imagery to distinguish algal blooms from aquatic vegetation, and analyzed the spatial and temporal variations of algal blooms and aquatic vegetation from a phenological perspective for five large natural lakes with frequent algal bloom outbreaks in China from 2019 to 2020. We simplified the VPF method to make it with a higher spatial transferability so that it could be applied to other lakes in different climatic zones. Through accuracy validation, we found that the modified VPF method can effectively distinguish between algal blooms and aquatic vegetation, and the results vary from lake to lake. The highest accuracy of 97% was achieved in Hulun Lake, where the frequency of algal outbreaks is low and the extent of aquatic vegetation is stable, while the lowest accuracy of 76% was achieved in Dianchi Lake, which is rainy in summer and the lake is small. Analyses suggests that the time period when algal blooms occur most frequently might not coincide with that when they have the largest area. However, in most cases these two are close in terms of time period. The modified VPF method has a broad scope of application, is easy to implement, and has a high practical value. Furthermore, the method could be established using only a small amount of measured data, which is useful for water quality monitoring on large spatial scales.
文摘Tb(111) and Ca(11) ion equilibria in the presence of glutamic acid and glutamine were studied by potentiometric titration at 37'C and an ionic strength of 0. 15mol/L(NaCl) .The stability constants for Tb(111) and Ca(11)complexes in the systems were obtained. The species and their distribution in the systems were discussed.
基金Project supported by the National Natural Science Foundation of China
文摘Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ternary complex becomes more stable than before. For analytical application, the derivative spectrofluorimetric method has high sensitivity and the effect of foreign ions is very low. The optimum conditions were obtained. The calibration graph is linear over 5~100μg/mL.