Purpose:The purpose of this study is to develop and compare model choice strategies in context of logistic regression.Model choice means the choice of the covariates to be included in the model.Design/methodology/appr...Purpose:The purpose of this study is to develop and compare model choice strategies in context of logistic regression.Model choice means the choice of the covariates to be included in the model.Design/methodology/approach:The study is based on Monte Carlo simulations.The methods are compared in terms of three measures of accuracy:specificity and two kinds of sensitivity.A loss function combining sensitivity and specificity is introduced and used for a final comparison.Findings:The choice of method depends on how much the users emphasize sensitivity against specificity.It also depends on the sample size.For a typical logistic regression setting with a moderate sample size and a small to moderate effect size,either BIC,BICc or Lasso seems to be optimal.Research limitations:Numerical simulations cannot cover the whole range of data-generating processes occurring with real-world data.Thus,more simulations are needed.Practical implications:Researchers can refer to these results if they believe that their data-generating process is somewhat similar to some of the scenarios presented in this paper.Alternatively,they could run their own simulations and calculate the loss function.Originality/value:This is a systematic comparison of model choice algorithms and heuristics in context of logistic regression.The distinction between two types of sensitivity and a comparison based on a loss function are methodological novelties.展开更多
Social networks like Facebook, X (Twitter), and LinkedIn provide an interaction and communication environment for users to generate and share content, allowing for the observation of social behaviours in the digital w...Social networks like Facebook, X (Twitter), and LinkedIn provide an interaction and communication environment for users to generate and share content, allowing for the observation of social behaviours in the digital world. These networks can be viewed as a collection of nodes and edges, where users and their interactions are represented as nodes and the connections between them as edges. Understanding the factors that contribute to the formation of these edges is important for studying network structure and processes. This knowledge can be applied to various areas such as identifying communities, recommending friends, and targeting online advertisements. Several factors, including node popularity and friends-of-friends relationships, influence edge formation and network growth. This research focuses on the temporal activity of nodes and its impact on edge formation. Specifically, the study examines how the minimum age of friends-of-friends edges and the average age of all edges connected to potential target nodes influence the formation of network edges. Discrete choice analysis is used to analyse the combined effect of these temporal factors and other well-known attributes like node degree (i.e., the number of connections a node has) and network distance between nodes. The findings reveal that temporal properties have a similar impact as network proximity in predicting the creation of links. By incorporating temporal features into the models, the accuracy of link prediction can be further improved.展开更多
Introduction: The use of foods containing high levels of sugar is increasing all the time. This is a risk factor for increased incidence of type 2 diabetes. There are few studies that have investigated the availabilit...Introduction: The use of foods containing high levels of sugar is increasing all the time. This is a risk factor for increased incidence of type 2 diabetes. There are few studies that have investigated the availability of low-sugar müsli products in grocery stores. Purpose: The study aims to identify which types of müsli contain high respectively low levels of sugar, and which brands are involved. Methods: The material consists of both qualitative interviews and observations from five grocery stores: City Gross, Hemköp, Ica Maxi, Stora Coop and Willy’s in Helsingborg, Sweden. The qualitative interviews had a semi-structured character and were recorded. The interviews took approx. 20 minutes and a textual analysis was conducted of the results. Data from observation was analyzed based on brand, nutritional composition and flavors, and also, where low sugar products were placed on store shelves. Results: The grocery stores provided together brands from AXA, Coop, Finax, Frebaco, Garant, ICA, Risenta, Saltå Kvarn och Urtekram, in total 24 müsli products. Of these products, 19 were high in sugar. The observation reveals that müsli products with high sugar content (17 - 29 g per 100 g müsli) are more prominently displayed than those with low sugar content. From the interviews with the store managers, it became clear that it would be valuable to highlight healthy müsli products on the shelves. However, central bureaucracy puts obstacles to such measures. Discussion: The study emphasizes the need for increased visibility of low-sugar products and proposes solutions such as negotiating with responsible person at the head office in Stockholm. Several reviews have shown that if the grocery store raises the prices of unhealthy food, the consumer is willing to purchase healthier müsli and other products. Conclusion: This study shows the need for grocery stores to upgrade healthy müsli products along with advertising to be able to influence customer’s shopping habits. Also, further research is needed how type 2 diabetes is affected by high intakes of food products with high sugar content.展开更多
Hanoi’s rapid urbanization has led to a surge in private vehicle ownership, particularly motorcycles, amidst inadequate public transportation infrastructure. Despite government efforts, many still prefer motorized tr...Hanoi’s rapid urbanization has led to a surge in private vehicle ownership, particularly motorcycles, amidst inadequate public transportation infrastructure. Despite government efforts, many still prefer motorized transport, citing mobility and safety concerns, exacerbated by insufficient pedestrian infrastructure. This study examines the motivations behind this reliance on motorized vehicles, particularly motorcycles, in Hanoi. Findings reveal safety and convenience as primary factors driving motorized transport use, especially for accessing bus stations. Economic incentives could promote non-motorized travel and public transport adoption. Policy implications highlight the importance of addressing economic factors and improving access infrastructure to manage motorized vehicle reliance and foster sustainable urban mobility in Hanoi.展开更多
As the Editor-in-Chief of World Journal of Gastroenterology,every week prior to a new issue’s online publication,I perform a careful review of all encompassed articles,including the title,clinical and/or research imp...As the Editor-in-Chief of World Journal of Gastroenterology,every week prior to a new issue’s online publication,I perform a careful review of all encompassed articles,including the title,clinical and/or research importance,originality,novelty,and ratings by the peer reviewers.Based on this review,I select the papers of choice and suggest pertinent changes(e.g.,in the title)to the Company Editors responsible for publication.This process,while time-consuming,is very important for assuring the quality of publications and highlighting important articles that Readers may revisit.展开更多
AIM:To evaluate residents’perceptions and attitudes toward the various aspects of a comprehensive ophthalmic examination,and to determine if these factors correlate with their choices for fellowship and future career...AIM:To evaluate residents’perceptions and attitudes toward the various aspects of a comprehensive ophthalmic examination,and to determine if these factors correlate with their choices for fellowship and future career plans.METHODS:This is a cross-sectional study.A questionnaire on the perception of the ophthalmic exam was sent via SurveyMonkey to ophthalmology residents throughout Israel.Eighty of them(one-half of all ophthalmology residents in 2019)completed it.The first part related to how they perceived each component of the ophthalmic evaluation.The second part related to their future fellowship plans.The Chi-squared test was used to compare categorical variables and Student’s t-test and One-way ANOVA were used to compare continuous variables.Multivariate logistic regression analysis was applied as needed to detect interactions between variables and to exclude confounder effects.RESULTS:Slit-lamp examination of the anterior and posterior segments ranked as the most likeable aspects,whereas gonioscopy,ocular motility examination and visual acuity assessment were least likeable.Anterior segment and retina subspecialties were the ones most sought after.Forty-nine respondents(61.3%)noted a direct correlation between their preferred parts of comprehensive ophthalmic evaluations and their choice of subspecialty.Perceptions of selected components of those evaluations were significantly associated with responders’intentions to pursue anterior segment,retina,or oculoplastic fellowships(P<0.05).CONCLUSION:Perspectives of residents toward the ophthalmic examination,and most specifically its individual components,play an important role in their choice of subspecialty training.展开更多
In the context of rising life expectancy,there is a significant discrepancy between Chinese seniors’self-perceptions of the start of old age and the expectations of society around this age.The traditional paradigm,wh...In the context of rising life expectancy,there is a significant discrepancy between Chinese seniors’self-perceptions of the start of old age and the expectations of society around this age.The traditional paradigm,which forecasts individual economic behavior and formulates economic policies based on societal standards of age,is put to the test by this disparity.This study,which draws from the China Longitudinal Aging Society Survey(CLASS),examines the factors,processes,and improvement strategies that affect how older people choose to work.The following are our conclusions:(i)Chinese elderly believe their old age starts from 70 years on average;delaying perceived old age is a denial of aging and raises the likelihood of finding work.Elders who are youthful at heart have a 2.4%higher chance of remaining employed than elders who are old at heart.(ii)In contrast to old-at-heart elders,young-at-heart elders are more likely to maintain their middle-age lifestyles,continue working,become motivated to engage in social activities,and gain the confidence to face challenges and continue in their career.(iii)If the perceived old age is above 70 years,the milestone event of aging is retirement from work,and there are external pressures,particularly pressures from family intergenerational support,the perception of old age will have a more proactive impact on older workers.(iv)Despite rising pension benefits,older people’s decision to remain in the workforce is still heavily influenced by their perception of their age.However,this effect is notably gender-specific,as older women’s decision to remain in the workforce is not greatly influenced by their own perception of their age.展开更多
This paper examined consumers’experiences in and preferences for plant-based meat(PBM)food and their respective correlates,based on data from an online survey of 579 consumers in four major cities in China in early 2...This paper examined consumers’experiences in and preferences for plant-based meat(PBM)food and their respective correlates,based on data from an online survey of 579 consumers in four major cities in China in early 2021.We first described consumers’experiences in consuming and purchasing PBM food and their correlates,and then analyzed consumer preferences using hypothetical choice experiment.The experiment offered consumers various options to purchase burgers made from PBM or animal-based meat(ABM),combined with different countries of origin(COO),taste labels,and prices.Our data showed that respondents hold overall positive attitudes toward PBM food;85 and 82%of respondents reported experience in eating and purchasing PBM food,respectively.More than half of them ate PBM food because they wanted to try new food(58%),or were interested in healthy food(56%).Income,religion,and dietary restrictions were significantly correlated with consumers’experiences in PBM food consumption.Results from the Random Parameter Logit Model based on the hypothetical choice experiment data showed that 79%of respondents chose PBM burgers and were willing to pay an average of 88 CNY for a PBM burger.We also found that 99.8 and 83%of respondents are willing to buy burgers made in China and those with a taste label,with a willingness to pay(WTP)of 208 and 120 CNY,respectively.The heterogeneity test revealed that females and those with at least a bachelor’s degree,higher income,religious beliefs,and dietary restrictions are more likely to buy PBM burgers than their counterparts.展开更多
In response to the unprecedented uncertain rare events of the last decade,we derive an optimal portfolio choice problem in a semi-closed form by integrating price diffusion ambiguity,volatility diffusion ambiguity,and...In response to the unprecedented uncertain rare events of the last decade,we derive an optimal portfolio choice problem in a semi-closed form by integrating price diffusion ambiguity,volatility diffusion ambiguity,and jump ambiguity occurring in the traditional stock market and the cryptocurrency market into a single framework.We reach the following conclusions in both markets:first,price diffusion and jump ambiguity mainly determine detection-error probability;second,optimal choice is more significantly affected by price diffusion ambiguity than by jump ambiguity,and trivially affected by volatility diffusion ambiguity.In addition,investors tend to be more aggressive in a stable market than in a volatile one.Next,given a larger volatility jump size,investors tend to increase their portfolio during downward price jumps and decrease it during upward price jumps.Finally,the welfare loss caused by price diffusion ambiguity is more pronounced than that caused by jump ambiguity in an incomplete market.These findings enrich the extant literature on effects of ambiguity on the traditional stock market and the evolving cryptocurrency market.The results have implications for both investors and regulators.展开更多
Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincia...Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincial panel data from 2016 to 2019 to study the impact mechanism of R&D investment on green technology innovation,and introduces the level of digitization,using the panel threshold model to discuss its role in the impact mechanism of R&D investment on green technology innovation.The study found that when the level of digitalization in a region is low,increasing R&D investment does not necessarily improve the ability of green technology innovation;when the level of digitalization is relatively high,R&D investment has a positive role in promoting green technology innovation.Therefore,it is necessary to improve policies to encourage enterprises to increase investment in research and development;at the same time,it is necessary to promote the coordinated development of digital foundation,digital investment,digital literacy,digital economy and digital application,and promote the deep integration of digitalization and green technology innovation.展开更多
文摘Purpose:The purpose of this study is to develop and compare model choice strategies in context of logistic regression.Model choice means the choice of the covariates to be included in the model.Design/methodology/approach:The study is based on Monte Carlo simulations.The methods are compared in terms of three measures of accuracy:specificity and two kinds of sensitivity.A loss function combining sensitivity and specificity is introduced and used for a final comparison.Findings:The choice of method depends on how much the users emphasize sensitivity against specificity.It also depends on the sample size.For a typical logistic regression setting with a moderate sample size and a small to moderate effect size,either BIC,BICc or Lasso seems to be optimal.Research limitations:Numerical simulations cannot cover the whole range of data-generating processes occurring with real-world data.Thus,more simulations are needed.Practical implications:Researchers can refer to these results if they believe that their data-generating process is somewhat similar to some of the scenarios presented in this paper.Alternatively,they could run their own simulations and calculate the loss function.Originality/value:This is a systematic comparison of model choice algorithms and heuristics in context of logistic regression.The distinction between two types of sensitivity and a comparison based on a loss function are methodological novelties.
文摘Social networks like Facebook, X (Twitter), and LinkedIn provide an interaction and communication environment for users to generate and share content, allowing for the observation of social behaviours in the digital world. These networks can be viewed as a collection of nodes and edges, where users and their interactions are represented as nodes and the connections between them as edges. Understanding the factors that contribute to the formation of these edges is important for studying network structure and processes. This knowledge can be applied to various areas such as identifying communities, recommending friends, and targeting online advertisements. Several factors, including node popularity and friends-of-friends relationships, influence edge formation and network growth. This research focuses on the temporal activity of nodes and its impact on edge formation. Specifically, the study examines how the minimum age of friends-of-friends edges and the average age of all edges connected to potential target nodes influence the formation of network edges. Discrete choice analysis is used to analyse the combined effect of these temporal factors and other well-known attributes like node degree (i.e., the number of connections a node has) and network distance between nodes. The findings reveal that temporal properties have a similar impact as network proximity in predicting the creation of links. By incorporating temporal features into the models, the accuracy of link prediction can be further improved.
文摘Introduction: The use of foods containing high levels of sugar is increasing all the time. This is a risk factor for increased incidence of type 2 diabetes. There are few studies that have investigated the availability of low-sugar müsli products in grocery stores. Purpose: The study aims to identify which types of müsli contain high respectively low levels of sugar, and which brands are involved. Methods: The material consists of both qualitative interviews and observations from five grocery stores: City Gross, Hemköp, Ica Maxi, Stora Coop and Willy’s in Helsingborg, Sweden. The qualitative interviews had a semi-structured character and were recorded. The interviews took approx. 20 minutes and a textual analysis was conducted of the results. Data from observation was analyzed based on brand, nutritional composition and flavors, and also, where low sugar products were placed on store shelves. Results: The grocery stores provided together brands from AXA, Coop, Finax, Frebaco, Garant, ICA, Risenta, Saltå Kvarn och Urtekram, in total 24 müsli products. Of these products, 19 were high in sugar. The observation reveals that müsli products with high sugar content (17 - 29 g per 100 g müsli) are more prominently displayed than those with low sugar content. From the interviews with the store managers, it became clear that it would be valuable to highlight healthy müsli products on the shelves. However, central bureaucracy puts obstacles to such measures. Discussion: The study emphasizes the need for increased visibility of low-sugar products and proposes solutions such as negotiating with responsible person at the head office in Stockholm. Several reviews have shown that if the grocery store raises the prices of unhealthy food, the consumer is willing to purchase healthier müsli and other products. Conclusion: This study shows the need for grocery stores to upgrade healthy müsli products along with advertising to be able to influence customer’s shopping habits. Also, further research is needed how type 2 diabetes is affected by high intakes of food products with high sugar content.
文摘Hanoi’s rapid urbanization has led to a surge in private vehicle ownership, particularly motorcycles, amidst inadequate public transportation infrastructure. Despite government efforts, many still prefer motorized transport, citing mobility and safety concerns, exacerbated by insufficient pedestrian infrastructure. This study examines the motivations behind this reliance on motorized vehicles, particularly motorcycles, in Hanoi. Findings reveal safety and convenience as primary factors driving motorized transport use, especially for accessing bus stations. Economic incentives could promote non-motorized travel and public transport adoption. Policy implications highlight the importance of addressing economic factors and improving access infrastructure to manage motorized vehicle reliance and foster sustainable urban mobility in Hanoi.
文摘As the Editor-in-Chief of World Journal of Gastroenterology,every week prior to a new issue’s online publication,I perform a careful review of all encompassed articles,including the title,clinical and/or research importance,originality,novelty,and ratings by the peer reviewers.Based on this review,I select the papers of choice and suggest pertinent changes(e.g.,in the title)to the Company Editors responsible for publication.This process,while time-consuming,is very important for assuring the quality of publications and highlighting important articles that Readers may revisit.
文摘AIM:To evaluate residents’perceptions and attitudes toward the various aspects of a comprehensive ophthalmic examination,and to determine if these factors correlate with their choices for fellowship and future career plans.METHODS:This is a cross-sectional study.A questionnaire on the perception of the ophthalmic exam was sent via SurveyMonkey to ophthalmology residents throughout Israel.Eighty of them(one-half of all ophthalmology residents in 2019)completed it.The first part related to how they perceived each component of the ophthalmic evaluation.The second part related to their future fellowship plans.The Chi-squared test was used to compare categorical variables and Student’s t-test and One-way ANOVA were used to compare continuous variables.Multivariate logistic regression analysis was applied as needed to detect interactions between variables and to exclude confounder effects.RESULTS:Slit-lamp examination of the anterior and posterior segments ranked as the most likeable aspects,whereas gonioscopy,ocular motility examination and visual acuity assessment were least likeable.Anterior segment and retina subspecialties were the ones most sought after.Forty-nine respondents(61.3%)noted a direct correlation between their preferred parts of comprehensive ophthalmic evaluations and their choice of subspecialty.Perceptions of selected components of those evaluations were significantly associated with responders’intentions to pursue anterior segment,retina,or oculoplastic fellowships(P<0.05).CONCLUSION:Perspectives of residents toward the ophthalmic examination,and most specifically its individual components,play an important role in their choice of subspecialty training.
基金supported by the General Project of the National Social Science Fund of China(NSSFC)(Grant No.19BRK028)Humanities and Social Science Research Youth Fund Project of the Ministry of Education:“Study on the Trends and Management of Population Outflow in China’s Border Regions”(Grant No.21YJC840021).
文摘In the context of rising life expectancy,there is a significant discrepancy between Chinese seniors’self-perceptions of the start of old age and the expectations of society around this age.The traditional paradigm,which forecasts individual economic behavior and formulates economic policies based on societal standards of age,is put to the test by this disparity.This study,which draws from the China Longitudinal Aging Society Survey(CLASS),examines the factors,processes,and improvement strategies that affect how older people choose to work.The following are our conclusions:(i)Chinese elderly believe their old age starts from 70 years on average;delaying perceived old age is a denial of aging and raises the likelihood of finding work.Elders who are youthful at heart have a 2.4%higher chance of remaining employed than elders who are old at heart.(ii)In contrast to old-at-heart elders,young-at-heart elders are more likely to maintain their middle-age lifestyles,continue working,become motivated to engage in social activities,and gain the confidence to face challenges and continue in their career.(iii)If the perceived old age is above 70 years,the milestone event of aging is retirement from work,and there are external pressures,particularly pressures from family intergenerational support,the perception of old age will have a more proactive impact on older workers.(iv)Despite rising pension benefits,older people’s decision to remain in the workforce is still heavily influenced by their perception of their age.However,this effect is notably gender-specific,as older women’s decision to remain in the workforce is not greatly influenced by their own perception of their age.
基金support from the National Natural Science Foundation of China(71861147003,71925009,72141014).
文摘This paper examined consumers’experiences in and preferences for plant-based meat(PBM)food and their respective correlates,based on data from an online survey of 579 consumers in four major cities in China in early 2021.We first described consumers’experiences in consuming and purchasing PBM food and their correlates,and then analyzed consumer preferences using hypothetical choice experiment.The experiment offered consumers various options to purchase burgers made from PBM or animal-based meat(ABM),combined with different countries of origin(COO),taste labels,and prices.Our data showed that respondents hold overall positive attitudes toward PBM food;85 and 82%of respondents reported experience in eating and purchasing PBM food,respectively.More than half of them ate PBM food because they wanted to try new food(58%),or were interested in healthy food(56%).Income,religion,and dietary restrictions were significantly correlated with consumers’experiences in PBM food consumption.Results from the Random Parameter Logit Model based on the hypothetical choice experiment data showed that 79%of respondents chose PBM burgers and were willing to pay an average of 88 CNY for a PBM burger.We also found that 99.8 and 83%of respondents are willing to buy burgers made in China and those with a taste label,with a willingness to pay(WTP)of 208 and 120 CNY,respectively.The heterogeneity test revealed that females and those with at least a bachelor’s degree,higher income,religious beliefs,and dietary restrictions are more likely to buy PBM burgers than their counterparts.
基金support from the Fundamental Research Funds for the Central Universities(22D110913)Jingzhou Yan gratefully acknowledges the financial support from the National Social Science Foundation Youth Project(21CTJ013)+1 种基金Natural Science Foundation of Sichuan Province(23NSFSC2796)Fundamental Research Funds for the Central Universities,Postdoctoral Research Foundation of Sichuan University(Skbsh2202-18).
文摘In response to the unprecedented uncertain rare events of the last decade,we derive an optimal portfolio choice problem in a semi-closed form by integrating price diffusion ambiguity,volatility diffusion ambiguity,and jump ambiguity occurring in the traditional stock market and the cryptocurrency market into a single framework.We reach the following conclusions in both markets:first,price diffusion and jump ambiguity mainly determine detection-error probability;second,optimal choice is more significantly affected by price diffusion ambiguity than by jump ambiguity,and trivially affected by volatility diffusion ambiguity.In addition,investors tend to be more aggressive in a stable market than in a volatile one.Next,given a larger volatility jump size,investors tend to increase their portfolio during downward price jumps and decrease it during upward price jumps.Finally,the welfare loss caused by price diffusion ambiguity is more pronounced than that caused by jump ambiguity in an incomplete market.These findings enrich the extant literature on effects of ambiguity on the traditional stock market and the evolving cryptocurrency market.The results have implications for both investors and regulators.
文摘Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincial panel data from 2016 to 2019 to study the impact mechanism of R&D investment on green technology innovation,and introduces the level of digitization,using the panel threshold model to discuss its role in the impact mechanism of R&D investment on green technology innovation.The study found that when the level of digitalization in a region is low,increasing R&D investment does not necessarily improve the ability of green technology innovation;when the level of digitalization is relatively high,R&D investment has a positive role in promoting green technology innovation.Therefore,it is necessary to improve policies to encourage enterprises to increase investment in research and development;at the same time,it is necessary to promote the coordinated development of digital foundation,digital investment,digital literacy,digital economy and digital application,and promote the deep integration of digitalization and green technology innovation.
