Flexner's legacy and the future of medical education:Embracing challenge and opportunity

This editorial comments on the article by Alzerwi.We focus on the development course,present challenges,and future perspectives of medical education.Modern medical education is gradually undergoing significant and profound changes worldwide.The emergence of new ideas,methodologies,and techniques has created opportunities for medical education developments and brought new concerns and challenges,ultimately promoting virtuous progress in medical education reform.The sustainable development of medical education needs joint efforts and support from governments,medical colleges,hospitals,researchers,administrators,and educators.

略论游憩机会谱(Recreation Opportunity Spectrum,ROS)框架体系

游憩机会谱为规划和管理游憩资源提供了框架。它被证明是一种有效的游憩机会清单分类方法,能够帮助确认管理决策的后果以及作为一种手段向公众通告有关游憩资源环境的信息及其预期的体验。对ROS的概念进行了阐述,并介绍了确定谱系分级因子的标准以及主要的应用目的。最后对游憩机会谱在中国的应用前景提出了两点展望。

Agricultural Land Use Responses to the Rising Labor Opportunity Cost in Sui County,China

Rising labor opportunity cost is one of the most important characteristics of farmers' economic environment in present China,and brings great agricultural land use changes correspondingly.Based on the stratified random sample of rural households in Sui County,this paper estimates the opportunity cost of farm labors,and then analyzes its effect on farmers' agricultural land use decisions.The findings show that the households with higher labor opportunity cost are more likely to reduce labor intensity and increase labor-saving input in their land use decisions.From the descriptive analysis,we also find these households always prefer grain crop planting,reduce yield-raising input or even rent out their cultivated land.As labor and yield-raising input are two essential positive factors for grain production,continuous declining of labor input and yield-raising input caused by rising labor opportunity cost may influence the grain yield per unit area in the future.

Agricultural opportunity costs assessment based on planting suitability:a case study in a mountain county in southwest China

Payment for ecosystem services(PES) has become an increasingly popular means of ecosystem conservation. Opportunity cost is an important factor to increase the investment efficiency of PES projects.However, the distribution of opportunity cost is usually unclear in mountainous regions due to the obvious environment changes. In this study, we developed a framework to assess the distribution of agricultural opportunity costs in mountainous regions and applied this method to Baoxing County, a typical mountainous county in Sichuan Province of southwest China. Planting suitability of 17 crops was assessed based on agricultural statistics and natural conditions data within a GIS environment.Agricultural opportunity cost was quantified with a weighted summation of farmers' willingness to cultivate and each crop's opportunity cost. Finally,specific agricultural opportunity cost was obtained according to the spatial areas of the protection programs and land use status. The results showed that agricultural opportunity costs of PES in Baoxing County were estimated to be more than $30 million,with a mean of 400.85 $/ha. Agricultural opportunity costs in mountainous regions displayed some obvious spatial variation and areas with lower agricultural opportunity costs could be selected as priority areas for PES. Our findings revealed that the planting suitability evaluation can make agricultural opportunity costs mapping more reasonable. It will be helpful for the PES programs implementation in mountainous regions.

Risk-opportunity analyses and production peak forecasting on world conventional oil and gas perspectives

To investigate the situation of conventional oil and gas, this paper examines the global oil and gas discoveries, proved reserves, production, consumption and price. All the influencing factors can be subjected to risk and opportunity analyses, so in the paper, we build upon a risk-opportunity analysis framework, which is a new train of thought. To forecast the peak time of oil and gas production, we used the methods of multi-Hubbert model forecasting and data forecasting. Our results showed that the world oil production will reach a peak between 2010 and 2015 and the gas production will reach a peak around 2030 Oil peak is coming and gas peak is on the way. The main purpose of forecasting oil and gas production peak is give people enough time for preparing mitigation and adaptation plans. This means taking decisive action well before the problem is obvious.

Analysis of Factors Influencing Farmers' Identification of Entrepreneurial Opportunity

Based on the survey data of entrepreneurship concerning farmers in China,this article uses the multivariate adjustment regression analysis method,to analyze the factors influencing farmers' identification of entrepreneurial opportunity and the mechanism. The results show that demographic characteristics are still an important factor influencing farmers' identification of entrepreneurial opportunity,but the extent of its influence is weaker than entrepreneurs' trait. The new trait theory is verified in farmers' entrepreneurship opportunity behavior; entrepreneurship environment is becoming an important factor influencing entrepreneurial opportunity identification,whose regulation effect on entrepreneurs' social network and previous experience is stronger than the regulation effect on entrepreneurs' psychological trait.

Opportunity Costs of Emissions Caused by Land-Use Changes

Amid the euphoria of Reducing Emissions from Deforestation and Forest Degradation (REDD) and REDD+ discussions, the expectations of large financial gains raise the interest of all. A country, however, will only enjoy REDD benefits if the cost of REDD is lower than the benefit. The opportunity cost analysis is an effective tool for assessing the feasibility of REDD+ since the largest portion of costs associated with REDD+ and can help to identify fair compensation for those who change their land use. The opportunity cost analysis has been exercised in Tanjung Jabung Barat (Tanjabar) district-Indonesia to examine the economic-feasibility of carbon emission reduction under different type carbon price scenarios. This study reveals a sharp decline of land-use systems with high carbon-stock and low profitability is obvious. On mineral soil, low carbon-stock and high profitability (mostly oil palm) has increased rapidly, especially in the period 2000-2009. It has become the dominant land-use system. The low-to-medium carbon stock and medium profitability land-use category increased from 1990 to 2005 but declined from 2005 to 2009. The low carbon-stock and low profitability category was constant and the proportion of the area was below 15%. The ex-ante analysis in predicting the potential for future emissions reduction in Tanjabar through REDD+ approaches shows that the cumulative emission of Tanjabar in 2020 is estimated at 61.91 Mg CO2-eq/Ha.Year, while the reduced emission by excluding all land use conversion below $5 threshold is estimated at 51.71 Mg CO2-eq/Ha.Year. This means that there is a potential for 16% emission reduction using $5/ton CO2-eq incentive. Another important finding in this study is that if the price of carbon increases by double to $10, the amount of reduced emission does not change much. This can use as a basis for determining the right amount of incentive for trade-off between economic profitability and climate change mitigation effort in Tanjabar using REDD+ scheme both at seller and buyer perspectives.

Tourism sectorization opportunity spectrum model and space partition of tourism urbanization area:a case of the Mayangxi ecotourism area,Fujian province,China

Nowadays, tourism has become an increasingly significant driving force of modern urbanization in China. However, it has caused varieties of problems, such as resource unreasonable utilization, society unfair play, and environment pollution, etc. Thus, the establishment of an efficient and sustainable space partition model for tourism urbanization, from the geographical perspective, is highly necessary and urgent. Herein, a new evaluation model of tourist town space, referred to as Tourism Sectorization Opportunity Spectrum(TSOS), is established on the relationships between productionliving-ecology spaces. TSOS is a kind of quantitative evaluation model involving such factors as urban living area, ecological conservation area and the tourism industry. Furthermore, the analysis of quantitative production-living-ecology spatial overlap has been utilized for space division in a tourism urbanization area. This paper, using both the TSOS model and GIS technology, analyzes the spatial restructure of the Mayangxi ecotourism area. Theresult demonstrates that tourism industrial space takes the Shanchong Village as a core which shows a pattern of local regional agglomeration and a fuzzy edge extending along the entire Mayangxi River. The urban living area should be consolidated in the Shili village with the supporting facilities and living space for tourism. In addition, Tianzhu Mountain forest park should be the key environmental protection area. The case study on the Mayangxi ecotourism area verifies that the TSOS model has strong operability. Therefore, TSOS model provides a scientific foundation for the space reconstruction of new urbanization area, and an effective tool for optimizing the space partition of a tourism urbanization area.

Challenge and opportunity of ionic liquidsdAn interview with Prof.Douglas R.Macfarlane

Expert Profile:Prof.Douglas R.MacFarlane is an Australian Laureate Fellow at Monash University's School of Chemistry and leader of the Energy Program in the Australian Centre for Electromaterials Science.He is the Australian Academy of Science's Craig Medalist 2018 and winner of the Victoria Prize for Science and Innovation 2018.

ROLE OF INTERVENING OPPORTUNITY IN TOURIST DESTINATION DEVELOPMENT

Intervening opportunity is an important factor in spatial interaction, and has very important impacts on tourist destination development in a region. There are few literatures on this topic in tourist researches, and especially in China fewer tourist researchers pay attention to intervening opportunity theory. This article, taking Lin’an as a case study, aims to introduce intervening opportunity theory in tourist destination development by the comprehensive ana-lysis of some data including literatures, Internet information, longitudinal data and some tourist surveys. Both qualitative and quantitative methods are all used in this research. Firstly, the authors expatiate upon the definition of intervening opportunity, by reviewing the literatures in detail, take Lin’an of Zhejiang Province as a case study, and then analyze some necessary factors of intervening opportunity, such as regional tourist demands and supplies, tourist attractions, spatial distance and transportation, tourist images and costs, regional competition and cooperation in tourist destinations. Finally the impacts of intervening opportunity on Lin’an tourist development are analyzed in detail. The results show that intervening opportunity do not occur everywhere, and there must be some critical factors, and intervening opportunity surely plays important roles in tourist destination development. The tourist development in Lin’an is attributed to intervening opportunity of the spatial location between Hangzhou and Huangshan that are two famous tourist cities in China, and the occurrence of intervening opportunities in Lin’an is the integration of some external and internal factors.

Estimating the opportunity costs of avoiding oil palm-based deforestation in Indonesia:Implications for REDD

Reducing emissions due to deforestation is considered a low-cost option for mitigating climate change.However,the recent literature suggests higher opportunity costs because of specific deforestation drivers,which render reducing emissions from deforestation and forest degradation(REDD+)for mitigating climate change an uncertain,less attractive,and controversial option.Indonesia is one of the largest greenhouse gas emitters.Since 1989,53.80%of its oil palm expansion has come from forestlands,which has generated a significant amount of carbon emissions.This study uses official data and results from the relevant literature to estimate the costs of oil palm-based deforestation under various scenario assumptions,including different output prices,yields,time horizons,and discount rates.We also calculate the additional cost to preserve a 1-ha forest.We demonstrate that the average opportunity cost from avoiding oil palm-based deforestation is 24.42 USD/tCO_(2)eq in Indonesia,approximately 1.3 times the 2011 EUA carbon price.Additional sums of around 5,466.90–11,042.96 USD/ha should be provided to landowners for the deforestation avoidance caused by oil palm expansion.Special attention should be given to the extensive oil palm expansion in Indonesia and the resulting high opportunity costs for achieving the REDD+​target.

Astroglial heterogeneity:merely a neurobiological question? Or an opportunity for neuroprotection and regeneration after brain injury?

Pioneer studies by Ramon y Cajal in the early nineteenth century evidenced that astrocytes are a heterogeneous cell population. The initial division of the glial family proposed by Rudolf Albert von Kolliker and William Lloyd Andriezen that separated glia into two groups, fibrous glia and protoplasmic glia, was further refined by Ramon y Cajal,

Strategies for Prioritizing Ecological Construction with Consideration of Agricultural Industry Development in Northern China’s Agro- pastoral Ecotone : A Perspective of Opportunity Cost

In northern China’s agro-pastoral ecotone,there are conflicts between agricultural industry and ecological construction resource competition,and also problems urgently to be solved for economic growth and sustainable ecological improvement.Taking the development concept of"lucid waters and lush mountains being mountains of gold and silver"as the guiding principle of prioritizing ecological and green development,this paper studied the strategies for prioritizing ecological construction with consideration of economic development of agricultural industry from the perspective of opportunity cost.Through the analysis of opportunity cost,externality,and Pareto optimal theory,and using the calculation method of the unit equivalent factor value of terrestrial ecological service function,this paper calculated the ecological service value of forest,grassland,and farmland.It found that the ecological value of forest and grassland per unit area was greater than the ecological value of agricultural industry.This indicates that the opportunity cost of farmland for ecological construction was less than that of agricultural industry.Based on the theoretical and quantitative analysis,it came up with recommendations for establishing a comprehensive system for prioritizing ecological construction with consideration of agricultural industry development and establishing and improving the incentive mechanism of ecological construction.

Oligodendroglioma: CD44 as a possible prognostic opportunity

CD44, in its standard form as well in its isoforms, is a cell surface adhesion glycoprotein which occurs in a widevariety of non-neoplastic and neoplastic ceils. CD44 has been considered to be implicated in tumoral growth andin metastatic potential. We studied the immunohistochemical expression of CD44 standard in 30 oligodendrogliomas(19 primary lesions and 11 recurrences) in order to verify its possible prognostic role. Twelve primary oligoden-

The research on the Bangladesh-China-India-Myanmar economic corridor： opportunity and challenge

This paper discusses the opportunity and challenge faced by the Bangladesh-China-India-Myanmar economic corridor. The opportunities include the complementary of economic structure and natural resources pattern, as well as the geographic linkage. The challenges include the funding shortage, the lack of political trust, the divergence on the investment priority, and the vulnerable ethnic situation. Finally, this paper looks into the future and expresses the optimistic view on the economic corridor.

The Farmer Entrepreneurs' Social Capital and Opportunity Recognition Behavior

Using the multivariate ordered logistic and probit regression method,based on the survey data of entrepreneurship concerning farmers in China,we analyze the impact of social capital ( namely the social network) on the farmers' recognition of entrepreneurial opportunities and property of entrepreneurial opportunities. The research results show that the scale of farmers being embedded in social network has a positive effect on the probability of farmers to recognize entrepreneurial opportunities. The higher the frequency of contact and the greater the size of weak ties network in the social network,then the greater the possibility of farmers to find innovative opportunities. But strong ties network has no significant effect on replicating-type entrepreneurial opportunities. At the same time,the entrepreneurial farmers' education experience, migrant worker experience,innovation capability,and deep entrepreneurial atmosphere,are all important factors affecting the farmers' opportunity recognition

Measuring the effect of opportunity cost of time on participation in sports and exercise

Background: There is limited research on the association between opportunity cost of time and sports and exercise due to lack of data on opportunity cost of time. Using a sample of 14142 adults from Health Survey for England (2006), we develop and test a composite index of opportunity cost of time (to address the current issues with data constraint on opportunity cost of time) in order to explore the relationship between opportunity cost of time and sports participation. Methods: Probit regression models are fitted adjusting for a range of covariates. Opportunity cost of time is measured with two proxy measures: a) composite index (consisting of various indicators of wage earnings) constructed using principal component analysis;and b) education and employment, approach in the literature. We estimate the relative impact of the composite index compared with current proxy measures, on prediction of sports participation. Findings: Findings suggest that higher opportunity cost of time is associated with increased likelihood of sports participation, regardless of the time intensity of activity or the measure of opportunity cost of time used. The relative impacts of the two proxy measures are comparable. Sports and exercise was found to be positively correlated with income. Another important positive correlate of sports and exercise is participation in voluntary activity. The research and policy implications of our findings are discussed.

Biodiversity Risk and Opportunity Assessment in BAT Cooperative Tobacco-growing Areas

Using the method in Biodiversity Risk and Opportunity Assessment Handbook of British American Tobacco Biodiversity Partnership,we assess biodiversity risks and opportunities in BAT and China's cooperative tobacco-growing areas. The assessment results indicate that there are 8 risks and 1 opportunity. Action and monitoring plans have been made for medium and high risks as well as opportunity,to reduce impact on biodiversity.

Multi-QoS Guaranteed Resource Allocation for Multi-Services Based on Opportunity Costs

To meet the booming development of diversified services and new applications in the future, the fifth-generation mobile conmmnication system （5G） has arisen. Resources are increasingly scarce in the @namic time-varying of 5G networks. Allocating resources effectively and ensuring quality of service （QoS） requirements of multi-seiwices come to be a research focus. In this paper, we utilize effective capacity to build a utility function with multi-QoS metrics, including rate, delay bound and packet loss ratio. Taking advantage of opportunity cost （OC）, we also propose a multi-QoS guaranteed resource allocation algm＇ithm for multi-services to consider the future condition of system. In the algorithm, according to different business characteristics and the theory of OC, we propose different selection conditions for QoS users and best effort （BE） users to choose more reasonable resources. Finally, simulation results show that our proposed algorithm achieves superior system utility and relatively better fairness in multi-service scenarios.

Utilizing Occupancy Models and Platforms-of-Opportunity to Assess Area Use of Mother-Calf Humpback Whales

The Hawaiian Islands, and particularly the Maui 4-island region, are a critical breeding and calving habitat for humpback whales (Megaptera novaeangliae) belonging to the Hawaii distinct population segment. Our aims were to test the use of platforms-of-opportunity to determine trends in mother-calf pod use of the region and to present opportunistic platforms as an alternative method of long-term, cross-seasonal monitoring. Data were collected from whale watching vessels over a 4-year period and analyzed using occupancy models to determine the probability of habitat use of pods with calves and pods without calves within the study area. Detection probability was influenced by survey effort and month for all pod types with detection of adult only pods further influenced by year. Pods with a calf showed a preference for shallow (<100 meters) low latitude waters (<20.7°N), while pods without a calf preferred deeper waters (>75 meters). Results presented here align with previous work, both in Hawaii and in other breeding grounds, which show a distinct segregation of mothers with a calf from other age-classes of humpback whales. The need for long-term continuous monitoring of cetacean populations is crucial to ensure species conservation. Data collected aboard platforms-of-opportunity, as presented here, provide important insight on humpback whale spatial and temporal distribution, which are essential for species protection and management.