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Variations in neuronal connectivity occur widely in nervous systems from invertebrates to mammals. Yet, it is unclear how neuronal variability originates, to what extent and at what time scales it exists, and what functional consequences it might carry. To assess inter- and intraindividual neuronal variability, it would be ideal to analyze the same identified neuron across different brain hemispheres and individuals. Here, using genetic labeling and electron microscopy connectomics, we show that an identified inhibitory olfactory local interneuron, TC-LN, exhibits extraordinary variability in its glomerular innervation patterns. Moreover, TC-LN’s innervation of the VL2a glomerulus, which processes food signals and modulates mating behavior, is sexually dimorphic, is influenced by female’s courtship experience, and correlates with food intake in mated females. Mating also affects output connectivity of TC-LN to specific local interneurons. We propose that mating-associated variability of TC-LNs regulates how food odor is interpreted by an inhibitory network to modulate feeding.

Several large or mid-scale collections of Drosophila enhancer traps have been recently created to allow for genetic swapping of GAL4 coding sequences to versatile transcription activators or suppressors such as LexA, QF, split-GAL4 (GAL4-AD and GAL4-DBD), GAL80 and QS. Yet a systematic analysis of the feasibility and reproducibility of these tools is lacking. Here we focused on InSITE GAL4 drivers that specifically label different subpopulations of olfactory neurons, particularly local interneurons (LNs), and genetically swapped the GAL4 domain for LexA, GAL80 or QF at the same locus. We found that the major utility-limiting factor for these genetic swaps is that many do not fully reproduce the original GAL4 expression patterns. Different donors exhibit distinct efficacies for reproducing original GAL4 expression patterns. The successfully swapped lines reported here will serve as valuable reagents and expand the genetic toolkits of Drosophila olfactory circuit research.

Drosophila olfactory local interneurons (LNs) in the antennal lobe are highly diverse and variable. How and when distinct types of LNs emerge, differentiate, and integrate into the olfactory circuit is unknown. Through systematic developmental analyses, we found that LNs are recruited to the adult olfactory circuit in three groups. Group 1 LNs are residual larval LNs. Group 2 are adult-specific LNs that emerge before cognate sensory and projection neurons establish synaptic specificity, and Group 3 LNs emerge after synaptic specificity is established. Group 1 larval LNs are selectively reintegrated into the adult circuit through pruning and re-extension of processes to distinct regions of the antennal lobe, while others die during metamorphosis. Precise temporal control of this pruning and cell death shapes the global organization of the adult antennal lobe. Our findings provide a road map to understand how LNs develop and contribute to constructing the olfactory circuit., Local interneurons (LNs) in the Drosophila olfactory system are highly diverse. Here, the authors labeled different LN types and described how different LN subtypes are integrated into the developing circuit.

China is quickly installing advanced metering infrastructure (AMI), which could provide tremendous opportunities in developing and utilizing demand response resources. Demand response may potentially create a profitable industry and contribute to efficiency improvement, cost reduction, and pollution mitigation of the entire electricity sector. However, China lags behind the developed world in utilizing demand response. Institutional barriers, including the lack of competitive electricity market and the resistance by the state grid corporations, are preventing the commercialization of demand response. In order to fully realize the potential of smart grid, China needs to push forward the reforms toward establishing an open access electricity market so the pollution-free demand response resources may compete with power generators on leveled field.

The Chinese government is promoting several coal conversion technologies as a part of its clean coal action plan. All of these coal conversion technologies have very high carbon footprints. The pro...

The Drosophila olfactory system is an attractive model for exploring the wiring logic of complex neural circuits. Remarkably, olfactory local interneurons exhibit high diversity and variability in their morphologies and intrinsic properties. Although olfactory sensory and projection neurons have been extensively studied of development and wiring; the development, mechanisms for establishing diversity, and integration of olfactory local interneurons into the developing circuit remain largely undescribed. In this review, we discuss some challenges and recent advances in the study of Drosophila olfactory interneurons.

Models show that to avert dangerous levels of climate change, global carbon dioxide emissions must fall to zero later this century. Most of these emissions arise from energy use. Davis et al. review what it would take to achieve decarbonization of the energy system. Some parts of the energy system are particularly difficult to decarbonize, including aviation, long-distance transport, steel and cement production, and provision of a reliable electricity supply. Current technologies and pathways show promise, but integration of now-discrete energy sectors and industrial processes is vital to achieve minimal emissions. Net emissions of CO2 by human activities - including not only energy services and industrial production but also land use and agriculture - must approach zero in order to stabilize global mean temperature. Energy services such as light-duty transportation, heating, cooling, and lighting may be relatively straightforward to decarbonize by electrifying and generating electricity from variable renewable energy sources (such as wind and solar) and dispatchable ("on-demand") nonrenewable sources (including nuclear energy and fossil fuels with carbon capture and storage). However, other energy services essential to modern civilization entail emissions that are likely to be more difficult to fully eliminate. These difficult-to-decarbonize energy services include aviation, long-distance transport, and shipping; production of carbon-intensive structural materials such as steel and cement; and provision of a reliable electricity supply that meets varying demand. Moreover, demand for such services and products is projected to increase substantially over this century. The long-lived infrastructure built today, for better or worse, will shape the future. Here, we review the special challenges associated with an energy system that does not add any CO2 to the atmosphere (a net-zero emissions energy system). We discuss prominent technological opportunities and barriers for eliminating and/or managing emissions related to the difficult-to-decarbonize services; pitfalls in which near-term actions may make it more difficult or costly to achieve the net-zero emissions goal; and critical areas for research, development, demonstration, and deployment. It may take decades to research, develop, and deploy these new technologies. DOI Link: https://doi.org/10.1126/science.aas9793

China has a unique urban pipeline network of three types of fuel gases: manufactured gas (coal gas), Liquefied Petroleum Gas (LPG), and natural gas. Manufactured gas, which is often seen as an outdated technology in the western world, is still widely used in Chinese cities. LPG is distributed through community-based pipelines in many Chinese cities, in addition to its distribution in cylinders and can- isters in rural areas. Natural gas consumption is increasing throughout China, particularly as a cooking fuel. Expanding the production and supply of natural gas in China faces many challenges. In particular, China's controls on natural gas prices have deterred investment in exploration and natural gas imports. However, recent price decontrols of unconventional natural gas (defined in Chinas as shale gas, coal-bed methane, and coal-to-natural-gas), and recent pricing reforms, appear likely to increase natural gas use. The prospect for increased exploration is promising but will still depend greatly on the future of insti- tutional reforms. In the near term, regulatory reforms toward a more market-driven system will be the most critical issue in the development of China's fuel gas sector.

In 2013, China׳s national government abandoned its previous cautious policy and started to promote large-scale deployment of coal-based synthetic natural gas (SNG). Coal-based SNG is both carbon-intensive and very water-intensive. Driven by a smog crisis and the recession of coal industry, China׳s 2013 policy change is major setback in its long-term efforts in carbon mitigation and water conservation. The government of China made the policy change before the commercial commencement of China׳s first SNG demonstration plant. Since the commencement of China׳s SNG demonstration plant, many problems have started to appear. In this article, I discuss the nature of demonstration project and explain the danger in starting a crash program without evaluating the demonstration comprehensively and transparently.

China has made improving the thermal efficiencies of its coal-fired power plants a national priority. Official data show that the average thermal efficiency was enhanced from 31.3% in 2000 to 33.2% in 2005 and 36.9% in 2010. This paper aims to assess the validity of China's claimed improvement, examine major responsible factors, and identify future improvement opportunities. Recognizable factors can account for about 80% of the reported progress in the 10th Five-Year Plan (2001–2005) and about 85% in the 11th (2006–2010) to largely verify the reported progress. Engineering approaches—especially replacing inefficient power units with more efficient ones—are the largest contributing factors, while optimization approaches—particularly electricity dispatch—remains inefficient in China. In 2010, the explainable efficiency improvement might have avoided around 500 million tons of CO2 emissions. In comparison, although the United States was fairly static with most of its coal-fired power plants seriously outdated, it has more efficient electricity dispatch. In China's ongoing 12th Five-Year Plan (2011–2015), better dispatch patterns could be more important as opportunities for improvement through engineering approaches have been largely exhausted.

Pumped hydroelectric storage (PHES) is the most established technology for utility-scale electricity storage and has been commercially deployed since the 1890s. Since the 2000s, there has been revived interest in developing PHES facilities worldwide. Because most low-carbon electricity resources (e.g., wind, solar, and nuclear) cannot flexibly adjust their output to match fluctuating power demands, there is an increasing need for bulk electricity storage due to the increasing adoption of renewable energy. PHES has been the traditional way of storing energy. This chapter introduces PHES technology, its pros and cons, its historical developments, and its prospects.

Since China decontrolled coal prices, its coal price has risen steadily and been unusually volatile. In 2011 in particular, high coal prices and capped electricity prices in China discouraged coal-fired power generation, triggering widespread power shortages. We suggest that these coal-price disturbances could be symptomatic of a major change in pricing dynamics of global fossil-fuel markets, with increasing correspondence between coal and oil prices globally. Historically, global coal prices have been more stable and lower than oil and natural gas prices on a per-heat basis. In recent years, however, coal prices have been increasingly volatile worldwide and have tracked other fossil fuel prices more closely. Meanwhile, the recent development of unconventional gas has substantially decoupled US natural gas and oil prices. Technically, low US natural gas prices, with potential fuel switching, could drive US domestic coal prices lower. However, this effect is unlikely to counteract the overall trend in increasing coal consumption globally. China’s market size and unique, partially-controlled energy system make its reform agenda a key force in the global economy. Policymakers in the US, E.U. and elsewhere should monitor China’s economic reform agenda to anticipate and respond to changes accompanying China’s increasing importance in the global energy economy.

For more than a decade, Nobel laureate George Olah and coworkers have advocated the Methanol Economy – replacing petroleum-based fuels and chemicals with methanol and methanol-derivatives – as a path to sustainable development. A first step to this vision appears to be occurring in China. In the past five years, China has quickly built an industry of coal-based methanol and dimethyl ether (DME) that is competitive in price with petroleum-based fuels. Methanol fuels offer many advantages, including a high octane rating and cleaner-burning properties than gasoline. Methanol also has some disadvantages. A coal-based Methanol Economy could enhance water shortages in China, increase net carbon dioxide emissions, and add volatility to regional and global coal prices. China’s rapidly expanding Methanol Economy provides an interesting experiment for what could happen elsewhere if methanol is widely adopted, as proposed by Olah and researchers before him.

China is quickly building up its nuclear power capacity while the hailed nuclear renaissance in the United States has been largely stagnant. The political and industrial structures explain the divergent paths. This paper draws lessons from the French experiences in deploying nuclear power and uses the lessons in comparing Chinese and U.S. policies. An authoritative political system and state-owned utility industry allow China to emulate the French approaches such as government-backed financing and broad-scale deployment with standardized design. The democratic political system and fragmented utility industry, and the laissez-faire ideology in the United States, on the other hand, are unfavorable to a nuclear renaissance. The prospect of a nuclear revival in the United States remains highly uncertain. As China builds up its nuclear industry, it will be able to reduce carbon emissions without a carbon price through a national plan to deploy low-carbon nuclear electricity, while the United States cannot implement a climate policy without a carbon price. American politicians should stop using China's lack of carbon cap as an excuse for postponing the legislation of a carbon price.

As concerns about global warming grow, societies are increasingly turning to the use of intermittent renewable energy resources, where energy storage becomes more and more important. Pumped-hydro energy storage (PHES) is the most established technology for utility-scale electricity storage. Although PHES has continued to be deployed globally, its development in the United States has largely been dormant since the 1990s. In recent years, however, there has been a revival of commercial interests in developing PHES facilities. In this paper we examine the historical development of PHES facilities in the United States, analyze case studies on the controversies of disputed projects, examine the challenges to and conflicting views of future development in the United States, and discuss new development activities and approaches. The main limiting factors for PHES appear to be environmental concerns and financial uncertainties rather than the availability of technically feasible sites. PHES developers are proposing innovative ways of addressing the environmental impacts, including the potential use of waste water in PHES applications. In some cases, a properly designed PHES system can even be used to improve water quality through aeration and other processes. Such new opportunities and the increasing need for greater energy storage may lead policymakers to reassess the potential of PHES in the United States, particularly for coupling with intermittent renewable energy sources such as wind and solar power.

The original version of this Article contained errors in Figs. 4 and 6. In Fig. 4, panel a, text labels UAS-FLP and LexAop2>stop>myr::smGdP-HA were shifted upwards during typesetting of the figure, and in Fig. 6, panel h, the number 15 was incorrectly placed on the heat map scale. These have now been corrected in both the PDF and HTML versions of the Article.

China has seen explosive growth in the sales of electric bikes since 1998. The boom was triggered by Chinese local governments' efforts to restrict motorcycles in city centers. However, many Chinese cities have started to extend the restriction to electric bikes. Whether China's electric bike economy will continue to develop is highly uncertain. The experience of China's electric bike boom suggests that limiting the fossil-fueled alternatives could be an effective policy tool in fostering the commercialization of electric vehicles. The failure of Taiwan's electric scooter policy, on the other hand, indicates that subsidies alone may not be a sufficient launching strategy. The policy approach of limiting the alternatives deserves serious consideration if policymakers wish to foster electric vehicles.

Taiwan has not been able to join the existing global climate regime because of its ambiguous international status. The Kyoto Protocol and the restrictive accession rules of the United Nations Frame...

The global demand for platinum has consistently outgrown supply in the past decade. This trend likely will continue and the imbalance may possibly escalate into a crisis. Platinum plays pivotal roles in both conventional automobile emissions control and the envisioned hydrogen economy. A platinum crisis would have profound implications on energy and environment. On the one hand, inadequate platinum supply will prevent widespread commercialization of hydrogen fuel-cell vehicles. On the other hand, expensive platinum may enhance the competitiveness of hybrid, plug-in hybrid, and battery-powered electric cars. Policymakers should weigh the potential impacts of a platinum crisis in energy policy.

Climate change is a chronic yet unprecedented threat to civilization. Large scale abatement of greenhouse-gas emissions would require not only replacing carbon-intensive fuels (like coal and oil) with low-emission or carbon-free energy alternatives, but also replacing much of the infrastructure that uses primary and secondary energy. As a political issue, the scale of the problem makes carbon mitigation unique and difficult to resolve. Its chronic nature is another obstacle to implementation of policy in the near term. It would take decades to displace fossil fuels even if the technologies to do so were available. Furthermore, disagreement has arisen on whether currently available technologies are sufficient to significantly reduce emissions over the next several decades (Pacala and Socolow 2004; Hoffert et al. 2002). The notion of developing new technologies before mandating emissions reductions has gained currency in response to these complexities. The Bush Administration climate policy favors this line of thinking, rejecting any Kyoto-style arrangement involving mandatory targets and proposing the development of new technologies as an alternative (Bush 2005). Here we argue that such approaches are based on the misconception that innovations needed for carbon mitigation can be effectively and efficiently developed without carbon regulations. One concrete version of the “technology first” view has been expressed almost daily by scientists, political leaders, and others: Global warming problem can be solved in a timely fashion only through a crash research and development program similar to the Manhattan Project (Clinton 2005; Friedman 2005) or Apollo Project (See http://www.appolloalliance. org). The target of a “Manhattan Project” on Climate Change would be low-carbon technologies for energy generation and use. A common rationale for this approach is that the fossil-fueled greenhouse effect cannot be regulated away, an assertion that ignores the potential affect of regulation on innovation. Climatic Change (2007) 80:199–204 DOI 10.1007/s10584-006-9202-7

T United States and China are pursuing different choices of hydrocarbon feedstock for making chemicals. While the U.S. chemical industry is increasingly utilizing shale gas as feedstock to produce olefins and methanol, China is developing coal-to-olefins and coal-to-methanol. Shale gas chemicals are cheaper and cleaner than coal-based ones. By replacing those high-carbon coal-to-chemicals, the U.S. export of shale gas chemicals will be both profitable and environmentally beneficial. Ethylene, propylene, and methanol are the three most important building blocks in the chemical industry. In 2014, the world consumed about 160 million metric tons of ethylene, 90 million metric tons of propylene, and about 70 million metric tons of methanol. Ethylene and propylene are often grouped together with other alkenes and referred to as olefins. Olefins are made from steam cracking of hydrocarbons, with naphtha as the most common feedstock, followed by ethane and propane. Since the shale revolution, surplus of ethane and propane has triggered an investment boom in ethane crackers and exponential growth of propane/propylene exports. The announced projects are expected to increase the U.S. olefins production capacities by 14 million metric tons by 2020. The cheap and abundant ethane and propane provide the U.S. chemical industries with several competitive advantages. Manufacturing olefins from ethane and propane is cheaper, simpler, consume less energy, and less polluting than naphtha cracking. Meanwhile, China is pursuing the development of coal-toolefins (CTO). China’s 12th five-year plan (2011 to 2015) for olefins industry listed the development of CTO as a top priority. With favorable policies, China’s CTO production capacities have grown from 1.1 million metric tons per year in 2010 to 6.5 in 2014, and are expected to reach 12.4 by 2016. Coal-to-olefins requires high capital investment, complex processes, high energy consumption (therefore high carbon dioxide (CO2) emissions), and high water consumption. Despite the technical disadvantages, China is quickly building a coal-to-olefins industry with favorable government policies. For each metric ton of olefins output, ethane-to-olefins emit about 0.8 t of CO2, naphtha-to-olefins emit about 0.9 t, 1 whereas coal-to-olefins emit about 5.8 t. Similar dichotomy appears in the feedstock choice for methanol in the United States and China. While the U.S. companies are aggressively expanding methanol production from natural gas, China is building coal-to-methanol capacities. In the United States, the announced methanol projects are expected to increase the nationwide methanol production capacity from 1.6 million metric tons in 2013 to over 12 million metric tons per year by 2018, and nearly 30 million metric tons per year by the early 2020s. Because the U.S. domestic consumption of methanol has remained relatively stable at about 6 million metric tons per year, the expansion will transform the United States from a net importer to a major exporter. China is the world’s largest methanol consumer and the major target for U.S. methanol export. In 2014, China consumed about 41 million metric tons of methanol, which account for 55% of global demand. Meanwhile, China has been building a unique coal-tomethanol industry. Many coal-producing regions encourage investments in coal conversion to boost demand for coal. China has already more than enough methanol production capacities to meet its demand, yet it continues to build more. Coal-tomethanol is carbon intensive. Making a metric ton of methanol from coal emits roughly 5.3 t of CO2, while making the same amount from natural gas emits only 1.7 t. The capital investment for a coal-to-methanol plant is roughly twice as much as a methane-to-methanol plant of comparable capacity, while the feedstock costs are comparable. The capital cost of coal-to-olefins is nearly four times of that of an ethane steam cracker, with comparable feedstock costs. In terms of operation and maintenance (O&M) costs, such as catalysts, water, energy, and pollution treatment, coal-tochemicals are all much more expensive than shale gas chemicals (Figure 1). Due to great cost advantage, aggressive expansion of U.S. shale gas chemicals could eventually force some of the Chinese coal-to-chemicals producers out of business, and contribute to carbon mitigation by replacing the high-carbon coal-tochemicals.

China has recently pushed for investments in large-scale coal-fuelled synthetic natural gas plants. The associated carbon emissions, water needs and wider environmental impacts are, however, mostly neglected and could lock the country into an unsustainable development path.

T recent shale gas revolution has increased the supply of ethane to an unprecedented level. The unexpected surplus of ethane has led to exceedingly low prices and a waste of a resource. Currently, the principal use for ethane is ethylene production. The surplus of ethane is turning into an excess of ethylene. The recent collapse of oil prices has greatly lowered the costs of petroleum-based ethylene, and limits the demand for ethane from ethylene producers. A small proportion of ethane may be blended into natural gas, but the heat value specifications limit the amount of ethane allowed. An increasing amount of ethane will likely be flared, which is a controlled burning of the gas only to get rid of it. Some projections suggest that U.S. ethane production may outgrow demand by hundreds of thousands barrels per day in the coming years. Due to the lack of infrastructure to utilize ethane, it is considered a nuisance in shale gas development. The physical and chemical properties of ethane make it a good a transportation fuel. For the same volume, ethane carries slightly more energy than liquefied natural gas (LNG), but is free from the evaporation loss problem in cryogenic LNG systems. The infrastructure required for ethane transportation are similar to those for compressed natural gas (CNG) vehicles, where the same cylinder can carry more than twice amount of energy in ethane than in CNG. A typical welding cylinder designed for CNG with 16.5 MPa pressure rating can hold liquid ethane safely. Even in hot summer days, when the liquid ethane completely evaporates, the pressure will not rise above the pressure rating. The promotion of natural gas vehicles (NGVs) is faced with several challenges. The CNG vehicles have significantly shorter driving ranges per refill than their gasoline or diesel counterparts. The LNG vehicles have similar driving ranges to the conventional vehicles, but require expensive cryogenic supply chain. Ethane vehicles offer longer driving range than LNG vehicles without cryogenic systems. Utilizing ethane to replace natural gas in transportation could potentially lower the market barriers to a clean alternative fuel and accelerate the adoption of gas vehicles in the United States. The end-use carbon intensity of ethane fuel is slightly higher than natural gas, but significantly lower than gasoline and diesel. We were unable to locate any assessments on upstream emissions for ethane. However, because ethane is a byproduct in natural gas production, its upstream emissions should be similar to that of natural gas. Figure 1 shows the well-to-wheel

This paper presents a stochastic optimal control based methodology for real-time local ramp control in response to lane-blocking incidents on freeways. A discrete-time nonlinear stochastic system, which characterizes the time-varying relationships among lane traffic states, control variables, and point detector data, is proposed. In addition, a stochastic optimal control-based algorithm is developed to update the time-varying ramp metering control variables and incident-induced lane traffic states in real time. Preliminary test results indicate that the proposed ramp control method permits alleviating incident impacts efficiently particularly under low-volume and medium-volume incident conditions. Moreover, utilizing the proposed method, time-varying lane traffic states together with incident impacts on queue lengths and capacities can be estimated in parallel with incident-responsive ramp control to monitor the status of incident impact and provide incident-related traffic information for further applications, e.g., incident management.

In advance of the G8 summit held in Germany last month, US President George Bush reiterated his view that the best way to tackle global climate change is through technology, rather than by regulating emissions of greenhouse gases. He is not alone in this view. Indeed, political leaders of all persuasions, including US Senators Hilary Clinton and Charles Schumer, as well as many scientists, are arguing that global warming can only be solved through a crash research and development programme similar to the Manhattan or Apollo projects.

Using density functional theory calculations, we have investigated the effect of specific surface structures on the electronic properties of a graphene layer on the SiO2 substrate. Our results show that graphene monolayer is weakly bound to the siloxane and silanol surfaces via the van der Waals interactions with a binding energy of around 20%–40% of that in graphite. Our calculations also show that the silanol groups on the surface can induce significant valence charge redistribution in the interfacial region as well as on the graphene layer, which appear like the scattering centers that may degrade the carrier mobility in graphene. Nevertheless, we found no doping effect on graphene from the substrate for both the siloxane and silanol surface structures.