BackgroundAchieving climate targets will require a rapid transition to clean energy. However, renewable energy (RE) firms face financial, policy, and economic barriers to mobilizing sufficient investment in low-carbon technologies, especially in low- and middle-income countries. Here, we analyze the challenges and successes of financing the energy transition in Nigeria and Brazil using three empirically grounded levers: financing environments, channels, and instruments.ResultsWhile Brazil has leveraged innovative policy instruments to mobilize large-scale investment in RE, policy uncertainty and weak financing mechanisms have hindered RE investments in Nigeria. Specifically, Brazil's energy transition has been driven by catalytic finance from the Brazilian Development Bank (BNDES). In contrast, bilateral agencies and multilateral development banks (MDBs) have been the largest financiers of renewables in Nigeria. Policy instruments and public-private partnerships need to be redesigned to attract finance and scale market opportunities for RE project developers in Nigeria.ConclusionsWe conclude that robust policy frameworks, a dynamic public bank, strategic deployment of blended finance, and diversification of financing instruments would be essential to accelerate RE investment in Nigeria. Considering the crucial role of donors and MDBs in Nigeria, we propose a multi-stakeholder model to consolidate climate finance and facilitate the country's energy transition.

Calls to phase out fossil fuels and shift to renewable energy-based solutions dominate the global discussion on low-carbon energy transition. However, the nature of this transition may vary across different countries on account of opportunities for innovative solutions that balance socio-economic and environmental sustainability goals. This piece argues that natural gas (NG) still has a vital role in the near to long-term future energy mix. This position implies that the objective of quickly phasing out NG needs reassessing. We further argue that there remains an opportunity for NG to be a key enabler of a "just" future net-zero emission energy system by mid-century, especially with the political-economic realities of certain countries and new technological innovations around NG utilisation. In this case, we argue that an essential element of "justice" could mean that nations at various levels of economic development adopt different approaches to the energy transition. Thus, decarbonisation efforts must consider socio-economic realities and the different contexts of technology application. The proposed uniform reduced energy demand and the blocking of public financing to NG projects lack the nuance of a sustainable solution, especially related to Sub-Saharan Africa. Accordingly, our analysis suggests that the one-size-fits-all approach to climate action in the context of natural gas commercialisation needs a rethink and countries should be allowed to define low-carbon pathways considering their local circumstances.

Hundreds of gigawatts of renewable technologies, such as wind and solar, need to be installed to reach a zero-carbon electricity system that meets current and future energy needs. Locations of new installations are typically chosen based on wind and solar availability to maximize facilities' capacity factors. Here, we show that this is not always true in least-cost models, and optimal siting depends also on the flexibility of the electricity system. To show this, we use a macro-scale energy model to evaluate capacities and dispatch in least-cost electricity systems with distributed wind and solar generation supported by battery storage. If battery storage were free and widely available, chosen locations for wind and solar installations would inevitably be in regions with the highest wind and solar capacity factors. However, as the battery storage cost increases and thus storage capacity decreases, chosen locations have lower capacity factors and the electricity system is more reliant on wind generation. In the case of a system without energy storage, only wind generation would in fact meet certain periods of electricity demand. This study suggests that current optimal wind and solar siting may no longer be the least-cost solution as the storage cost decreases.

Inspired by the synthesis of XB3C3 (X = Sr, La) compounds in the bipartite sodalite clathrate structure, density functional theory (DFT) calculations are performed on members of this family containing up to two different metal atoms. A DFTchemical pressure analysis on systems with X = Mg, Ca, Sr, Ba reveals that the size of the metal cation, which can be tuned to stabilize the B-C framework, is key for their ambient-pressure dynamic stability. High-throughput density functional theory calculations on 105 Pm (3) over bar symmetry XYB6C6 binary-guest compounds (where X, Y are electropositive metal atoms) find 22 that are dynamically stable at 1 atm, expanding the number of potentially synthesizable phases by 19 (18 metals and 1 insulator). The density of states at the Fermi level and superconducting critical temperature, T-c, can be tuned by changing the average oxidation state of the metal atoms, with T-c being highest for an average valence of +1.5. KPbB6C6, with an ambient-pressure Eliashberg T-c of 88 K, is predicted to possess the highest Tc among the studied Pm (3) over barn XB3C3 or Pm (3) over bar XYB6C6 phases, and calculations suggest it may be synthesized using high-pressure high-temperature techniques and then quenched to ambient conditions.

The phase diagram of the Mg-C system has been constructed up to 20 GPa and similar to 4000 K based on complementary Thermo-Calc simulations and experimental data obtained in both ex situ and in situ experiments using X-ray diffraction with synchrotron radiation. Three high-pressure magnesium carbides, namely, beta-Mg2C3, its high-temperature form gamma-Mg2C3, and antifluorite Mg2C, have p-T domains of thermodynamic stability. At the same time, the carbides accessible by ambient-pressure synthesis, alpha-Mg2C3 and MgC2, are either metastable or unstable, depending on the temperature, at least up to 20 GPa. Experimental observations show that at ambient conditions, all carbides are metastable and remain unchanged at least for years.

In mammalian cell nuclei, the nuclear lamina (NL) underlies the nuclear envelope (NE) to maintain nuclear structure. The nuclear lamins, the major structural components of the NL, are involved in the protection against NE rupture induced by mechanical stress. However, the specific role of the lamins in repair of NE ruptures has not been fully determined. Our analyses using immunofluorescence and live-cell imaging revealed that the nucleoplasmic pool of lamin C rapidly accumulated at sites of NE rupture induced by laser microirradiation in mouse embryonic fibroblasts. The accumulation of lamin C at the rupture sites required both the immunoglobulin-like fold domain that binds to barrier-to-autointegration factor (BAF) and a nuclear localization signal. The accumulation of nuclear BAF and cytoplasmic cyclic GMP-AMP synthase (cGAS) at the rupture sites was in part dependent on lamin A/C. These results suggest that nucleoplasmic lamin C, BAF, and cGAS concertedly accumulate at sites of NE rupture for rapid repair.

Chondrites are undifferentiated meteorites that can provide information on the compositions of materials in the early solar System, including the building blocks of the terrestrial planets. While most chondrites belong to well-defined groups based on their mineralogy and chemical composition, a minor fraction have unusual characteristics and are classified as ungrouped chondrites. These ungrouped chondrites reflect the diversity of chondritic materials in the early solar system; however, they are not as well stud-ied as grouped meteorites and their origins are poorly understood. In this study, we present high -precision mass-independent Cr, Ca and Mg isotope data for 17 ungrouped chondrites. The epsilon 54Cr and epsilon 48Ca (epsilon expresses parts per ten thousand mass-independent isotope deviation) data for ungrouped chon-drites also provide important constraints for assessing their relationships to the known chondrite groups, and the radiogenic Mg isotope ratios (mu 26Mg*) can be used to track the early solar system history. We also present the first high-precision data for a Kakangari (KC) chondrite, an enstatite chondrite, and for four enstatite-rich meteorites. The epsilon 54Cr and epsilon 48Ca values for the KC are-0.44 +/- 0.04 and-1.30 +/- 0.25, respec-tively, and epsilon 48Ca value for SAH 97096 (EH3) is-0.19 +/- 0.22 that overlaps with that of those of Earth -Moon system and ordinary chondrites. All the carbonaceous chondrite-like (CC) ungrouped chondrites show positive epsilon 54Cr and epsilon 48Ca values, and all the non-carbonaceous chondrite-like (NC) ungrouped chon-drites and KCs (also belong to the NC trend) show zero or negative epsilon 54Cr and epsilon 48Ca values. This observa-tion confirms the CC-NC dichotomy for primitive solar system materials. LEW 87232 (KC) also shows the highest 55Mn/52Cr ratio and epsilon 53Cr value amongst all the chondrites. There is a positive trend between 55Mn/52Cr ratios and epsilon 53Cr values among all the chondrites that mostly reflects a mixing between mul-tiple chondritic components. Previously it has been reported that there is a bulk 26Al-26Mg correlation line amongst chondrites. This correlation has been interpreted as being due to mixing of CAIs (high 27Al/24Mg ratios and mu 26Mg* values) and other silicate material (e.g., chondrules and matrix). By provid-ing additional 26Al-26Mg chondrite data, we show that there is no 26Al-26Mg correlation line for the chon-drites, ruling out the two-endmember (i.e., CAIs and other silicates) mixing model.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Protoplanets formed in a marginally gravitationally unstable (MGU) disk by either core accretion or disk instability will be subject to dynamical interactions with massive spiral arms, possibly resulting in inward or outward orbital migration, mergers with each other, or even outright ejection from the protoplanetary system. The latter process has been hypothesized as a possible formation scenario for the unexpectedly high frequency of unbound gas giant exoplanets (free floating planets, FFPs). Previous calculations with the EDTONS fixed grid three-dimensional (3D) hydrodynamics code found that protoplanets with masses from 0.01 M (circle plus) to 3 M (Jup) could undergo chaotic orbital evolutions in MGU disks for similar to 1000 yr without undergoing monotonic inward or outward migration. Here the Enzo 2.5 adaptive mesh refinement 3D hydrodynamics code is used to follow the formation and orbital evolution of protoplanets in MGU disks for up to 2000 yr. The Enzo results confirm the basic disk fragmentation results of the EDTONS code, as well as the absence of monotonic inward or outward orbital migration. In addition, Enzo allows protoplanet mergers to occur, unlike EDTONS, resulting in a significant decrease in the number of protoplanets that survive for 1000-2000 yr in the Enzo models. These models also imply that gas giants should be ejected frequently in MGU disks that fragment into large numbers of protoplanets, supporting ejection as a possible source mechanism for the observed FFPs.