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Everything Under the Sun: A Guide to Siting Solar in the Lone Star State
Encouraging energy production using renewable resources is a widely recognized public policy that is promoted by both the federal and state governments in the U.S., and with recent technological advances, renewable-electricity generation is rapidly becoming economically viable. The Energy Information Administration (EIA) forecasts that electricity production from all renewable sources will increase 72% between 2013 and 2040, with the renewable share of total U.S. electricity generation growing from 13% to 18%.1 The future of solar power is especially bright with a projected growth rate of 6.8% per year between 2013 and 2040. If this projection holds true, solar power will far outpace the growth of other renewables. Combined with the Investment Tax Credit (ITC) introduced in 2006, rapid improvements in photovoltaic (PV) solar panel efficiency and dramatic reductions in PV costs are driving a veritable solar boom in the U.S. In fact, the Solar Energy Industries Association (SEIA) reports a 73% decrease in the cost of installing solar since the implementation of the ITC, and anticipates an additional 20,000 Megawatts (MW) of solar generation capacity will come online in the next two years, doubling current U.S. solar capacity. Likewise, the EIA projects that solar power will account for nearly half of the total 109,000MW of renewable-generation-capacity that is expected to be added to the U.S. electricity grid by 2040.The Kay Bailey Hutchison Center for Energy, Law, and Busines
Thermodynamic characterization of an engineered tetracycline-binding riboswitch
Riboswitches reflect a novel concept in gene regulation that is particularly suited for technological adaptation. Therefore, we characterized thermodynamically the ligand binding properties of a synthetic, tetracycline (tc)-binding RNA aptamer, which regulates gene expression in a dose-dependent manner when inserted into the untranslated region of an mRNA. In vitro, one molecule of tc is bound by one molecule of partially pre-structured and conformationally homogeneous apo-RNA. The dissociation constant of 770 pM, as determined by fluorimetry, is the lowest reported so far for a small molecule-binding RNA aptamer. Additional calorimetric analysis of RNA point mutants and tc derivatives identifies functional groups crucial for the interaction and including their respective enthalpic and entropic contributions we can propose detailed structural and functional roles for certain groups. The conclusions are consistent with mutational analyses in vivo and support the hypothesis that tc-binding reinforces the structure of the RNA aptamer, preventing the scanning ribosome from melting it efficiently
Investment Spikes: New Facts and a General Equilibrium Exploration
Using plant-level data from Chile and the U.S. we show that investment spikes are highly pro-cyclical, so much so that changes in the number of establishments undergoing investment spikes (the "extensive margin") account for the bulk of variation in aggregate investment. The number of establishments undergoing investment spikes also has independent predictive power for aggregate investment, even controlling for past investment and sales. We re-calibrate the Thomas (2002) model (that includes fixed costs of investing) so that it assigns a prominent role to extensive adjustment. The recalibrated model has different properties than the standard RBC model for some shocks.
What's Blocking the Sun?: Solar Photovoltaics for the U.S. Commercial Market
Provides an overview of installation trends and investment climate for solar photovoltaics in the U.S. commercial sector, including policy and economic obstacles. Recommends strategies for the solar industry, the commercial sector, and policy makers
Structural basis for dual roles of Aar2p in U5 snRNP assembly
Yeast U5 small nuclear ribonucleoprotein particle (snRNP) is assembled via a cytoplasmic precursor that contains the U5-specific Prp8 protein but lacks the U5-specific Brr2 helicase. Instead, pre-U5 snRNP includes the Aar2 protein not found in mature U5 snRNP or spliceosomes. Aar2p and Brr2p bind competitively to a C-terminal region of Prp8p that comprises consecutive RNase H-like and Jab1/MPN-like domains. To elucidate the molecular basis for this competition, we determined the crystal structure of Aar2p in complex with the Prp8p RNase H and Jab1/MPN domains. Aar2p binds on one side of the RNase H domain and extends its C terminus to the other side, where the Jab1/MPN domain is docked onto a composite Aar2p–RNase H platform. Known Brr2p interaction sites of the Jab1/MPN domain remain available, suggesting that Aar2p-mediated compaction of the Prp8p domains sterically interferes with Brr2p binding. Moreover, Aar2p occupies known RNA-binding sites of the RNase H domain, and Aar2p interferes with binding of U4/U6 di-snRNA to the Prp8p C-terminal region. Structural and functional analyses of phospho-mimetic mutations reveal how phosphorylation reduces affinity of Aar2p for Prp8p and allows Brr2p and U4/U6 binding. Our results show how Aar2p regulates both protein and RNA binding to Prp8p during U5 snRNP assembly
Adding Sweeteners to Softwood Lumber: The WTO-NAFTA “Spaghetti Bowl” Is Cooking
With the Doha round in trouble, the so-called spaghetti bowl of multilateral trade rules and proliferating regional trade deals, is, once again, prominently on the radar screen of the international trade community. Perfect examples of this image are the longstanding US-Canada softwood lumber and US-Mexico sweetener disputes. Both trade spats, extensively litigated in NAFTA and the WTO, are close to reaching a climax. Fueling the suspense is that the WTO and NAFTA may reach different results
Trick or Heat? Manipulating Critical Temperature-Based Control Systems Using Rectification Attacks
Temperature sensing and control systems are widely used in the closed-loop
control of critical processes such as maintaining the thermal stability of
patients, or in alarm systems for detecting temperature-related hazards.
However, the security of these systems has yet to be completely explored,
leaving potential attack surfaces that can be exploited to take control over
critical systems.
In this paper we investigate the reliability of temperature-based control
systems from a security and safety perspective. We show how unexpected
consequences and safety risks can be induced by physical-level attacks on
analog temperature sensing components. For instance, we demonstrate that an
adversary could remotely manipulate the temperature sensor measurements of an
infant incubator to cause potential safety issues, without tampering with the
victim system or triggering automatic temperature alarms. This attack exploits
the unintended rectification effect that can be induced in operational and
instrumentation amplifiers to control the sensor output, tricking the internal
control loop of the victim system to heat up or cool down. Furthermore, we show
how the exploit of this hardware-level vulnerability could affect different
classes of analog sensors that share similar signal conditioning processes.
Our experimental results indicate that conventional defenses commonly
deployed in these systems are not sufficient to mitigate the threat, so we
propose a prototype design of a low-cost anomaly detector for critical
applications to ensure the integrity of temperature sensor signals.Comment: Accepted at the ACM Conference on Computer and Communications
Security (CCS), 201
Imaging regulatory T cell dynamics and CTLA4-mediated suppression of T cell priming
Foxp3(+) regulatory T cells (Tregs) maintain immune homoeostasis through mechanisms that remain incompletely defined. Here by two-photon (2P) imaging, we examine the cellular dynamics of endogenous Tregs. Tregs are identified as two non-overlapping populations in the T-zone and follicular regions of the lymph node (LN). In the T-zone, Tregs migrate more rapidly than conventional T cells (Tconv), extend longer processes and interact with resident dendritic cells (DC) and Tconv. Tregs intercept immigrant DCs and interact with antigen-induced DC: Tconv clusters, while continuing to form contacts with activated Tconv. During antigen-specific responses, blocking CTLA4-B7 interactions reduces Treg-Tconv interaction times, increases the volume of DC: Tconv clusters and enhances subsequent Tconv proliferation in vivo. Our results demonstrate a role for altered cellular choreography of Tregs through CTLA4-based interactions to limit T-cell priming
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