The growth of point source plumes at Rayleigh numbers up to 108 and Prandtl numbers up to 1000

Two-dimensional numerical simulations were conducted of the growth of thermal plumes from a point heat source at Rayleigh numbers up to 108 and Prandtl numbers up to 1000. Scaling the convection equations by the free fall velocity rather than the thermal diffusivity, increased the Prandtl number range available to numerical simulation by one order of magnitude from Prandtl number 100 to 1000. We present animations showing how the plumes grow with time for different Prandtl numbers. Plumes with Prandtl numbers around 7 (water) were found to be unstable to sinuous instabilities; whereas those at Prandtl numbers of 1000 had straight stems and fewer sinuous instabilities. Wavelet analysis was used to analyze the scales at which plumes initiated, and the scales at which sinuous instabilities occurred. The scale of both the plume structures and instabilities was found to decrease with Prandtl number.     

The future of the mobile phone business

One of the fastest growing technologies of our times is that of mobile phones. In this article we use the assumption that the diffusion of mobile technology, as measured by the number of active mobile accounts, follows the well known S-curve of natural growth in competition systems. The accuracy of the logistic fit is tested against actual data for the whole world, Europe, China and the GSM system. Using the produced models predictions concerning the future of mobile business are deliberated.According to these models active mobile accounts around the globe are expected to grow from 1.7 billion in 2004 to approximately 2 billion in 2008, reaching a peak penetration of 29.2%. Growth barriers, apart from the age of the potential user, are also low income and extreme poverty. Europe, early adopter of mobile technology and leader in active mobile accounts against all other regions in the world, has apparently reached a peak with almost every European, apart from the very young or very old, using a mobile phone. The mobile market in China is anticipated to exceed 500 million active accounts and may increase even further depending on the economic and social reform that is currently under way in that part of the world. GSM will most likely remain the leading mobile technology in the future as it is today.The growth process for the world, Europe, and the GSM system is almost completed and during this stage instabilities may occur before the potential emergence of a new wave of growth.     

An Approach to a Visual Language for Convective Fluid Flows: Visualization of Geophysical Simulations

It was known that deep within numbers and binary data from simulations of geophysical convective flows resided various patterns. Two models of convective fluid flows were being considered. One was a model of two-dimensional (768 × 256) air convection with finite Prandtl number of one and Rayleigh number of 10⁸?10¹⁰, and another was a model of three-dimensional (up to 120 × 120 × 90) mantle convection with infinite Prandtl number and Rayleigh number of 10⁶?10⁸. Clearly, phenomena existed which superceded each individual dimensionless computer model to provide a piece of information regarding actual fluid flows. The problem was how to find, prove, and communicate these patterns and phenomena for convection simulations with gigabytes of data. In a search for such an analytical and communicative tool, the alternative of visualization was considered. The need for visualization was recognized and discussed. Then, utilizing both two- and three-dimensional models of high Rayleigh number convection, basic techniques of style and content were developed. Applications of the visualization techniques were designed utilizing IBM’s Data Explorer in order to create communicative images and movies, and after the applications, the problems of data storage and transfer became apparent. Throughout the process though, it became clear how important the language of vision actually could be in the geophysics community. In a field in which words such as plumes and internal waves have in ways replaced mathematics as the basic language for science, there is a need for another resource, another language-the visualization of convective fluid flows.     

Investment and employment from large-scale photovoltaics up to 2050

Investments in renewable energy were at US$211 billion in 2010 and developing economies overtook developed ones for the first time in terms of new financial investments in renewable energy. Photovoltaics for generation of electricity from sunlight has the highest growth rate among the competing forms of renewable energy and has now begun to achieve grid parity in some regions. If these trends of investments continue, solar energy will play a major economic role. We analyze these developments and assess the ensuing amounts of investment and employment for a range of sizes of the sector of solar energy. We find that by 2050 electricity from photovoltaics could cover up to 90% of total global energy demand, with a then global capital investment in our main scenario in photovoltaic manufacturing capacity at 500 billion US$211 billion in 2010 and developing economies overtook developed ones for the first time in terms of new financial investments in renewable energy. Photovoltaics for generation of electricity from sunlight has the highest growth rate among the competing forms of renewable energy and has now begun to achieve grid parity in some regions. If these trends of investments continue, solar energy will play a major economic role. We analyze these developments and assess the ensuing amounts of investment and employment for a range of sizes of the sector of solar energy. We find that by 2050 electricity from photovoltaics could cover up to 90% of total global energy demand, with a then global capital investment in our main scenario in photovoltaic manufacturing capacity at 500 billion US₂₀₁₀ by around 2030 and 1,500 billion by 2050. Employment in photovoltaic manufacturing is predicted to rise to 6 million by 2050. Sensitivity analysis with respect to the core parameters of assumptions is supplied.     

中美能源库兹涅茨曲线研究——基于正交偏最小二乘法

中国与美国能源库兹涅茨曲线是存在的,中国将在人均GDP达到2万美元左右到达能源消费总量拐点,产业结构变化影响较弱,经济危机反而刺激了能源消费;美国在2007年前后已经到达拐点,第三产业产值与工业比值每提高1个百分点,会减少大约1百万吨标准煤,每次经济危机会减少当年3千万吨标准煤。通过对比可知,目前中国属于高能耗模式,不利于可持续发展,应对经济危机应发挥市场自身的调节作用,从而达到优胜劣汰实现结构转型。     

THE VALUE OF VOLUNTEER LABOR AND THE FACTORS INFLUENCING PARTICIPATION: EVIDENCE FOR THE UNITED STATES FROM 2002 THROUGH 2005

According to the U.S. Department of Labor, the number of people who volunteered rose from 59.8 million in 2002 to 65.4 million in 2005. Those volunteering benefit from their activity in various ways; however, these benefits are non-pecuniary and are generally not recognized in the national economic accounts used to measure gross domestic product (GDP). This paper uses data from the 2002–05 Current Population Survey Volunteer Supplements to assign a dollar value to volunteering. Different methodologies yield annual estimates from $116 to $153 billion (in 2005 dollars) over the four years (between 0.9 and 1.3 percent of 2005 GDP). Additionally, characteristics of individuals most likely to volunteer are identified. The volunteer rate varies by demographic characteristics in addition to geographic location, labor force participation, and business sector. Furthermore, the data suggest that volunteering is a "normal good" because participation increases with income even after controlling for observables.     

An assessment of two environmental and economic benefits of ‘Cash for Clunkers’

This research aims to provide a more comprehensive, life cycle accounting of two categories of environmental and economic benefits associated with the $3 billion US “Cash for Clunkers” vehicle scrappage program. First, using a life cycle emissions methodology developed in Lenski et al. (2010), we find that about 29,000 metric tons of criteria pollutant emissions were avoided, for a benefit of about $23 million; avoided carbon dioxide emissions, by comparison, provided a benefit worth $90 million. Second, we compare the market value of scrapped vehicles to the rebates provided, calculating the consumer surplus or “gift” to participants to be up to $2 billion (about $2000 to $3000 per vehicle). This is significantly more than offered in previous vehicle scrappage programs, and suggests opportunities to get more environmental and economic “bang for the buck.” Finally, these two categories of benefits are found to be heavily concentrated geographically around urban centers. About 2% of US counties (50 counties) received 50% and 30% of the aggregate benefits from avoided criteria pollutant emissions and consumer surplus from the rebates, respectively.     

A global estimate of benefits from ecosystem-based marine recreation: potential impacts and implications for management

Participation in ecosystem-based marine recreational activities (MRAs) has increased around the world, adding a new dimension to human use of the marine ecosystem and another good reason to strengthen effective management measures. A first step in studying the effects of MRAs at a global scale is to estimate their socioeconomic benefits, which are captured here by three indicators: the amount of participation, employment and direct expenditure by users. A database of reported expenditure on MRAs was compiled for 144 coastal countries. A meta-analysis was then performed to calculate the yearly global benefits of MRAs in terms of expenditure, participation and employment. It is estimated that 121 million people a year participate in MRAs, generating 47 billion USD (2003) in expenditures and supporting one million jobs. The results of this study have several implications for resource managers and for the tourism industry. Aside from offering the first estimation of the global socioeconomic benefits of MRAs, this work provides insights on the drivers of participation and possible ecological impacts of these activities. Our results could also help direct efforts to promote adequate implementation of MRAs. Furthermore, we hope this work will provide a template for data collection on MRAs worldwide.     

Finite Prandtl number 2-D convection at high Rayleigh numbers

Finite Prandtl number thermal convection is important to the dynamics of planetary bodies in the solar system. For example, the complex geology on the surface of the Jovian moon Europa is caused by a convecting, brine-rich global ocean that deforms the overlying icy “lithosphere”. We have conducted a systematic study on the variations of the convection style, as Prandtl numbers are varied from 7 to 100 at Rayleigh numbers 106 and 108. Numerical simulations show that changes in the Prandtl number could exert significant effects on the shear flow, the number of convection cells, the degree of layering in the convection, and the number and size of the plumes in the convecting fluid. We found that for a given Rayleigh number, the convection style can change from single cell to layered convection, for increasing Prandtl number from 7 to 100. These results are important for determining the surface deformation on the Jovian moon Europa. They also have important implications for surface heat flow on Europa, and for the interior heat transfer of the early Earth during its magma ocean phase. Electronic Supplementary Material is available if you access this article at http://dx.doi.org/10.1007/s10069-002-0004-4. On that page (frame on the left side), a link takes you directly to the supplementary material.     

干旱区草型湖泊湿地价值量化评估

本文以典型干旱区草型湖泊乌梁素海湿地为研究区,在实地调查和试验的基础上,依据资源经济学和生态经济学的理论和方法,针对乌梁素海湿地资源的特点,对乌梁素海湿地的价值进行了货币化评估。评估结果表明,乌梁素海湿地的总价值为28．24×10~8元,其中直接实物产品价值为7164．70×10~4元,直接非实物服务价值为18 193．43×10~4元,间接价值为81 960．58×10~4元,目前非使用类价值为17．51×10~8元。只有合理开发乌梁素海湿地资源,保护好这一对区域环境具有重要意义的干旱区湿地生态系统,才能实现乌梁素海湿地资源的可持续利用,保证湖区经济的可持续发展。     

Macroeconomic costs to large scale disruptions of food production: The case of foot- and-mouth disease in the United States

We forecast the economic consequences of a widespread contamination of the food system based on a hypothetical outbreak of foot-and-mouth disease (FMD). Since the immediate effect on the livestock sector could affect the entire supply chain and US livestock, meat and dairy exports, we measure these impacts using GTAP, a multi-region, multi-sector computable general equilibrium (CGE) model of the global economy. The immediate “shocks” to the US livestock, raw milk and other animal products sectors indirectly affect all sectors of the economy, as well as international markets and trade. We decompose these effects due to each component of the initial shocks, and estimate the importance of these shocks to the national food system for the Mid-Atlantic Region using IMPLAN. Our GTAP results indicate that losses to the USA economy would be about $11.7 billion, and with the ripple effect throughout the rest of the world including beneficiary nations (Argentina, Brazil, Latin America, Australia and New Zealand) and losers (Canada, Mexico, European Union) would be 14.1 billion. We estimate the proportion of the domestic impact affecting the Mid-Atlantic Region. Based on a regional input–output model of that region, we estimate that total losses in value added are nearly $800 million; losses in labor income total about $565 million; and there are job losses of just over 12 thousand.     

Ubiquitous interactive visualization of 3D mantle convection using a web-portal with Java and Ajax framework

We have developed a new strategy and espouse a novel paradigm for large-scale computing and real-time interactive visualization. This philosophy calls for intense interactive sessions for a couple of hours at a time at the expense of storing data on many disk drives during regular or heroic runs on massively parallel systems. We have already carried out successfully real-time volume-rendering visualization by employing hundreds of processors for a grid with over 25 million unknowns. Both Cartesian and spherical 3D mantle convection are visualized. The volume-rendered images are viewed on a large display device, with many panels holding around 13 million pixels. We will employ a software strategy involving an hierarchical rendering service, which will have as software an Ajax interface for interactive visualization of large data sets on many different platforms from desktop PC’s to hand-held devices, such as the OQO and the Nokia N-800. An option for stereo viewing is also implemented. We have installed a user interface as web application, using Java and Ajax framework in order to achieve over the Internet reasonable accessibility to our ongoing runs. Our goal is to expand the array of interactive devices, which will make it feasible to carry out ubiquitous visualization and monitoring of large-scale simulations or onsite events and to allow for collaborations across oceans.     

Modelling economy-ecology linkages in mangroves: Economic evidence for promoting conservation in Bintuni Bay, Indonesia

Woodchip exports pose a potential threat to a 300 000-ha mangrove ecosystem in the Bintuni Bay area of Irian Jaya, Indonesia. The bay supports an important shrimp export industry, and coastal areas support 3000 households. Traditional non-commercial uses of mangroves have an estimated value of Rp20 billion/yr (US$10 million/yr); commercial fisheries are valued at Rp70 billion/yr (US$35 million/yr) and selective commercial mangrove cutting schemes have a maximum value of Rp40 billion/yr (US$20 million/yr).Forest management options, ranging from clear cutting to a cutting ban, are evaluated in a cost–benefit analysis incorporating linkages among mangrove conversion, offshore fishery productivity, traditional uses, and benefits of erosion control and biodiversity maintenance functions. “Linkage scenarios” are developed that reflect potential ecosystem component interactions in Bintuni Bay. Clear cutting is optimal only if linkages are ignored. A cutting ban is optimal if linear and immediate linkages between ecosystem components exist. Under a scenario with linear but delayed linkages of 5 years, selective cutting of 25% of the harvestable mangrove is the optimal strategy; it has a present value of Rp70 billion (US$35 million) greater than the clear cutting option, and more extensive cutting would yield no additional net benefits.Strong economic arguments exist for conservative mangrove clearing. Where strong ecological linkages occur, severe restrictions on clearing activities will be economically optimal. Where ecosystem dynamics are uncertain, programs reducing linkage effects – such as greenbelts, replanting, or selective cutting – will minimise potential economic losses.     

Cost efficiency and banking performances in a partial universal banking system: application of the panel smooth threshold model

This paper studies the cost efficiency of bank in a partial universal banking system (PUBS), Taiwan. Instead of assuming one common technology in the bank cost function, two technologies are assumed to be imbedded in the cost function. Fee revenues are used as threshold to divide the banks into two technologies. A bank whose fee revenues exceeding the threshold is designated as universal bank technology while falling below the threshold is designated as traditional deposit-loan technology. The panel smooth transition model is adopted, which allows banks to smoothly adjust between the two technologies. Two criteria are suggested, overbanking and the trend-toward-fee revenues, to assess the new model's performances. With respect to scale economies, the results do find a panel smooth transition model yield more reasonable results than the conventional OLS and random effect of panel data approach. Based on the panel smooth transition model, the optimal fixed asset size is around ten billion New Taiwan dollars.     

中国未来婚姻挤压研究

中国的男孩偏好和对女孩的歧视导致了男性婚姻挤压。在潜在初婚比模型的基础上,使用标准化初婚频率和去进度效应方法设计了两种新的模型,并与现有模型结合,研究中国婚姻挤压状况。在潜在初婚比基础上开发的模型所得到的结论基本相同。2016年到2046年的30年时间里,婚姻市场上男性和女性的潜在初婚比都在1.15以上;2060年之后保持在1.05-1.08水平。从2000年开始,中国会面临严重的男性婚姻挤压,2016年至2046年平均每年过剩男性在120-150万之间,2060年之后每年在50万之下。如果出生性别比得不到有效控制,则未来男性婚姻挤压情况将严重得多。     

Economic impact of ocean fish populations in the global fishery

Our goal in this paper is to estimate the total output in an economy that is currently dependent (at least partially) on current fisheries output. We therefore applied the Leontief technological coefficients at current production and then estimate total output supported throughout the economy at the current level of production. Estimates of gross revenue from capture fisheries suggest that the direct value of output for this sector is US $80–85 billion annually (Sumaila et al., Journal of Bioeconomics 9(1):39–51, 2007; Willmann et al., The Sunken Billions, World Bank, FAO, Washington DC, Rome, 2009). However, as a primary or a potential economic base industry, there are a vast number of secondary economic activities—from boat building to international transport—that are supported by world fisheries, yet these related activities are rarely considered when evaluating the economic impact of fisheries. This study applies an input–output methodology to estimate the total direct, indirect, and induced impact of marine capture fisheries on the world economy. While results suggest that there is a great deal of variation in fishing output multipliers between regions and countries, when we apply the output multipliers to the capture fisheries sector at the global level, we find that significant indirect and induced effects place the impact of this sector to world output nearly three times larger than the value of landings at first sale, at between US $80–85 billion annually (Sumaila et al., Journal of Bioeconomics 9(1):39–51, 2007; Willmann et al., The Sunken Billions, World Bank, FAO, Washington DC, Rome, 2009). However, as a primary or a potential economic base industry, there are a vast number of secondary economic activities—from boat building to international transport—that are supported by world fisheries, yet these related activities are rarely considered when evaluating the economic impact of fisheries. This study applies an input–output methodology to estimate the total direct, indirect, and induced impact of marine capture fisheries on the world economy. While results suggest that there is a great deal of variation in fishing output multipliers between regions and countries, when we apply the output multipliers to the capture fisheries sector at the global level, we find that significant indirect and induced effects place the impact of this sector to world output nearly three times larger than the value of landings at first sale, at between US 225 and 240 billion per year.     

Constitutional stability

Political scientists in the pluralist tradition disagree sharply with public and social choice theorists about the importance of institutions and with William Riker in particular, who argues inLiberalism against Populism that the liberal institutions of indirect democracy ought to be preferred to those of populism. This essay reconsiders this dispute in light of two ideas unavailable to Riker at the time. The first, offered by Russell Hardin, is that if we conceptualize constitutions as coordinating devices rather than as social contracts, then we can develop a more satisfying view of the way in which constitutions become self-enforcing. The second idea derives from the various applications of concepts such as the uncovered set. Briefly, although institutions such as the direct election of president are subject to the usual instabilities that concern social choice theorists, those instabilities do not imply that “anything can happen” —instead, final outcomes will be constrained, where the severity of those constraints depends on institutional details. We maintain that these ideas strengthen Riker's argument about the importance of such constitutional devices as the separation of powers, bicameralism, the executive veto, and scheduled elections, as well as the view that federalism is an important component of the institutions that stabilize the American political system. We conclude with the proposition that the American Civil War should not be regarded as a constitutional failure, but rather as a success. I have benefitted from the comments of a number of people on earlier drafts of this essay, especially William Riker, Emerson Niou, Kenneth Shepsle, Gordon Tullock, Thomas Schwartz, and Matthew Spitzer.     

The effects on agriculture in the United States of an oil import fee

This paper focuses on the effect that a crude oil import fee would have on the various producing sectors, consuming sectors and household categories in the United States where the interrelationships between these entities is explicitly considered. Special attention is given to the agricultural sectors of the economy. Thus, in the context of a general equilibrium model, the effect of a $5.00 per barrel import fee on the producing sectors in general and the three agricultural sectors plus forestry in particular, on the consuming sectors, on households and on the government is calculated. Over the period 1984–90 with such an import fee (relative to the absence of a crude–oil import fee), the model results suggest that there will be a reduction in output by all producing sectors (except the crude-oil industry) by about $13,924 billion, there will be a fall in the consumption of goods and services by about $318 million and there will be a decline in aggregate social welfare (measured as utility) by about $208 mill ion. The government will realize an increase in revenue of about $3,622 billion. The agricultural sectors in the aggregate can expect to see a fall in output of $769 million with an attendant increase in the price of its goods as a consequence of the oil import fee.     

Estimates of the direct and indirect cost savings associated with heart disease that could be avoided through dietary change in the United States

Aims: Diets high in saturated fat are associated with elevated risk of heart disease. This study estimates the savings in direct (medical care) costs and indirect (job absenteeism) costs in the US from reductions in heart disease associated with substituting monounsaturated fats (MUFA) for saturated fats.

Materials and methods: A four-part model of the medical care cost savings from avoided heart disease was estimated using data on 247,700 adults from the 2000–2010 Medical Expenditure Panel Survey (MEPS). The savings from reduced job absenteeism due to avoided heart disease was estimated using a zero-inflated negative binomial model of the number of annual work loss days applied to data on 164,577 adults from the MEPS.

Results: Estimated annual savings in medical care expenditures resulting from a switch from a diet high in saturated fat to a high-MUFA diet totaled ～ $25.7 billion (95% CI = $6.0–$45.4 billion) in 2010, with private insurance plans saving $7.9 billion (95% CI?=?$1.8–$14.0 billion), Medicare saving $9.4 billion (95% CI?=?$2.1–$16.7 billion), Medicaid saving $1.4 billion (95% CI?=?Aims: Diets high in saturated fat are associated with elevated risk of heart disease. This study estimates the savings in direct (medical care) costs and indirect (job absenteeism) costs in the US from reductions in heart disease associated with substituting monounsaturated fats (MUFA) for saturated fats.

Materials and methods: A four-part model of the medical care cost savings from avoided heart disease was estimated using data on 247,700 adults from the 2000–2010 Medical Expenditure Panel Survey (MEPS). The savings from reduced job absenteeism due to avoided heart disease was estimated using a zero-inflated negative binomial model of the number of annual work loss days applied to data on 164,577 adults from the MEPS.

Results: Estimated annual savings in medical care expenditures resulting from a switch from a diet high in saturated fat to a high-MUFA diet totaled ～ $25.7 billion (95% CI = $6.0–$45.4 billion) in 2010, with private insurance plans saving $7.9 billion (95% CI?=?$1.8–$14.0 billion), Medicare saving $9.4 billion (95% CI?=?$2.1–$16.7 billion), Medicaid saving $1.4 billion (95% CI?=?$0.2–$2.5 billion), and patients saving $2.2 billion (95% CI?=?$0.5–$3.8 billion). The annual savings in terms of reduced job absenteeism ranges from a lower bound of $600 million (95% CI?=?$100 million to $1.0 billion) to an upper bound of $1.2 billion (95% CI?=?$0.2–$2.1 billion) for 2010.

Limitations: The data cover only the non-institutionalized population. Decreased costs due to any decreases in the severity of heart disease are not included. Cost savings do not include any reduction in informal care at home.

Conclusions: Diets high in saturated fat impose substantial medical care costs and job absenteeism costs, and substantial savings could be achieved by substituting MUFA for saturated fat.