Countercyclical energy and climate policy for the US

Continuation of the U.S.'s historical pattern addressing energy problems only in times of crisis is unlikely to catalyze a transition to an energy system with fewer adverse social impacts. Instead, the U.S. needs to bolster support for energy innovation when the perceived urgency of energy-related problems appears to be receding. Because of the lags involved in both the energy system and the climate system, decarbonizing the economy will require extraordinary persistence over decades. This need for sustained commitment is in contrast to the last several decades, which have been marked by volatility and cycles of boom and bust. In contrast to the often-repeated phrase that one should 'never let a good crisis go to waste,' the U.S. needs to most actively foster energy innovation when aspects of energy and climate problems appear to be improving. We describe the rationale for a 'countercyclical' approach to energy and climate policy, which involves precommitment to a set of policies that go into effect once a set of trigger conditions are met

Risk-adapted screening in bladder cancer as a new strategy in bladder cancer is feasible using a computer-based questionnaire, Risikocheck V4.0, evaluated in an international multicentre trial

WOS: 00025383980025

μ‑Oxo Dimerization Effects on Ground- and Excited-State Properties of a Water-Soluble Iron Porphyrin CO₂ Reduction Catalyst

Iron 5,10,15,20-tetra(para-N,N,N-trimethylanilinium)porphyrin (Fe-p-TMA) is a water-soluble catalyst capable of electrochemical and photochemical CO2 reduction. Although its catalytic ability has been thoroughly investigated, the mechanism and associated intermediates are largely unknown. Previous studies proposed that Fe-p-TMA enters catalytic cycles as a monomeric species. However, we demonstrate herein that, in aqueous solutions, Fe-p-TMA undergoes formation of a μ-oxo porphyrin dimer that exists in equilibrium with its monomeric form. The propensity for μ-oxo formation is highly dependent on the solution pH and ionic strength. Indeed, the μ-oxo form is stabilized in the presence of electrolytes that are key components of catalytically relevant conditions. By leveraging the ability to chemically control and spectrally address both species, we characterize their ground-state electronic structures and excited-state photodynamics. Global fitting of ultrafast transient absorption data reveals two distinct excited-state relaxation pathways: a three-component sequential model consistent with monomeric relaxation and a two-component sequential model for the μ-oxo species. Relaxation of the monomeric species is best described as a ligand-to-metal charge transfer (τ1 = ∼500 fs), an ionic strength-dependent metal-to-ligand charge transfer (τ2 = 2–4 ps), and finally relaxation of a ligand field excited state to the ground state (τ3 = 5 ps). Conversely, excited-state relaxation of the μ-oxo species proceeds via cleavage of an FeIII–O bond to generate transient FeIVO and FeII porphyrin species (τ1 = 2 ps) that recombine to the ground-state μ-oxo species (τ2 = ∼1 ns). This latter lifetime extends to timescales relevant for chemical reactivity. It is therefore emphasized that further consideration of catalyst speciation and chemical microenvironments is necessary for elucidating the mechanisms of catalytic CO2 reduction reactions

Packing under tolerance constraints (preliminary version)

Available from TIB Hannover: RN 7879(9619) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDeutsche Forschungsgemeinschaft (DFG), Bonn (Germany)DEGerman