70 research outputs found
TMEDA in IronâCatalyzed Hydromagnesiation: Formation of Iron(II)âAlkyl Species for Controlled Reduction to AlkeneâStabilized Iron(0)
N,N,Nâ,NââTetramethylethylenediamine (TMEDA) has been one of the most prevalent and successful additives used in ironâcatalysis, finding application in reactions as diverse as crossâcoupling, CâH activation and borylation. However, the role that TMEDA plays in these reactions remains largely undefined. Herein, studying the ironâcatalyzed hydromagnesiation of styrene derivatives using TMEDA has provided molecularâlevel insight into the role of TMEDA in achieving effective catalysis. Key is the initial formation of TMEDAâiron(II) alkyl species which undergo a controlled reduction to selectively form catalytically active styreneâstabilized iron(0)âalkyl complexes. While TMEDA is not bound to the catalytically active species, these active iron(0) complexes cannot be accessed in the absence of TMEDA. This mode of action, allowing for controlled reduction and access to iron(0) species, represents a new paradigm for the role of this important reaction additive in iron catalysis
Toward mid-infrared, subdiffraction, spectral-mapping of human cells and tissue: SNIM (scanning near-field infrared microscopy) tip fabrication
Scanning near-field infrared microscopy (SNIM) potentially enables subdiffraction, broadband mid-infrared (MIR:3â25-Îźm wavelength range) spectral-mapping of human cells and tissue for real-time molecular sensing, with prospective use in disease diagnosis. SNIM requires an MIR-transmitting tip of small aperture for photon collection. Here, chalcogenide-glass optical fibers are reproducibly tapered at one end to form a MIR transmitting tip for SNIM. A wet-etching method is used to form the tip. The tapering sides of the tip are Al-coated. These Al-coated tapered-tips exhibit near-field power-confinement when acting either as the launch-end or exit-end of the MIR optical fiber. We report first time optimal cleaving of the end of the tapered tip using focused ion beam milling. A flat aperture is produced at the end of the tip, which is orthogonal to the fiber-axis and of controlled diameter. A FIB-cleaved aperture is used to collect MIR spectra of cells mounted on a transflection plate, under illumination of a synchrotron- generated wideband MIR beam
âTriple winsâ or âtriple faultsâ? Analysing the equity implications of policy discourses on climate-smart agriculture (CSA)
This paper analyses contrasting discourses of âclimate-smart agricultureâ (CSA) for their implications on control over and access to changing resources in agriculture. One of the principal areas of contestation around CSA relates to equity, including who wins and who loses, who is able to participate, and whose knowledge and perspectives count in the process. Yet to date, the equity implications of CSA remain an under-researched area. We apply an equity framework centred on procedure, distribution and recognition, to four different discourses. Depending on which discourses are mobilised, the analysis helps to illuminate: (1) how CSA may transfer the burden of responsibility for climate change mitigation to marginalised producers and resource managers (distributive equity); (2) how CSA discourses generally fail to confront entrenched power relations that may constrain or block the emergence of more âpro-poorâ forms of agricultural development, adaptation to climate change, or carbon sequestration and storage (procedural equity); (3) how CSA discourses can have tangible implications for the bargaining power of the poorest and most vulnerable groups (recognition). The paper contributes to work showing the need for deeper acknowledgement of the political nature of the transformations necessary to address the challenges caused by a changing climate for the agricultural sector
Too Big to Fail â U.S. Banksâ Regulatory Alchemy: Converting an Obscure Agency Footnote into an âAt Willâ Nullification of Dodd-Frankâs Regulation of the Multi-Trillion Dollar Financial Swaps Market
The multi-trillion-dollar market for, what was at that time wholly unregulated, over-the-counter derivatives (âswapsâ) is widely viewed as a principal cause of the 2008 worldwide financial meltdown. The Dodd-Frank Act, signed into law on July 21, 2010, was expressly considered by Congress to be a remedy for this troublesome deregulatory problem. The legislation required the swaps market to comply with a host of business conduct and anti-competitive protections, including that the swaps market be fully transparent to U.S. financial regulators, collateralized, and capitalized. The statute also expressly provides that it would cover foreign subsidiaries of big U.S. financial institutions if their swaps trading could adversely impact the U.S. economy or represent the use of extraterritorial trades as an attempt to âevadeâ Dodd-Frank. In July 2013, the CFTC promulgated an 80-page, triple-columned, and single-spaced âguidanceâ implementing Dodd-Frankâs extraterritorial reach, i.e., that manner in which Dodd-Frank would apply to swaps transactions executed outside the United States. The key point of that guidance was that swaps trading within the âguaranteedâ foreign subsidiaries of U.S. bank holding company swaps dealers were subject to all of Dodd-Frankâs swaps regulations wherever in the world those subsidiariesâ swaps were executed. At that time, the standardized industry swaps agreement contemplated that, inter alia, U.S. bank holding company swaps dealersâ foreign subsidiaries would be âguaranteedâ by their corporate parent, as was true since 1992. In August 2013, without notifying the CFTC, the principal U.S. bank holding company swaps dealer trade association privately circulated to its members standard contractual language that would, for the first time, âdeguaranteeâ their foreign subsidiaries. By relying only on the obscure footnote 563 of the CFTC guidanceâs 662 footnotes, the trade association assured its swaps dealer members that the newly deguaranteed foreign subsidiaries could (if they so chose) no longer be subject to Dodd-Frank. As a result, it has been reported (and it also has been understood by many experts within the swaps industry) that a substantial portion of the U.S. swaps market has shifted from the large U.S. bank holding companies swaps dealers and their U.S. affiliates to their newly deguaranteed âforeignâ subsidiaries, with the attendant claim by these huge big U.S. bank swaps dealers that Dodd-Frank swaps regulation would not apply to these transactions. The CFTC also soon discovered that these huge U.S. bank holding company swaps dealers were âarranging, negotiating, and executingâ (âANEâ) these swaps in the United States with U.S. bank personnel and, only after execution in the U.S., were these swaps formally âassignedâ to the U.S. banksâ newly âdeguaranteedâ foreign subsidiaries with the accompanying claim that these swaps, even though executed in the U.S., were not covered by Dodd-Frank. In October 2016, the CFTC proposed a rule that would have closed the âdeguaranteeâ and âANEâ loopholes completely. However, because it usually takes at least a year to finalize a âproposedâ rule, this proposed rule closing the loopholes in question was not finalized prior to the inauguration of President Trump. All indications are that it will never be finalized during a Trump Administration. Thus, in the shadow of the recent tenth anniversary of the Lehman failure, there is an understanding among many market regulators and swaps trading experts that large portions of the swaps market have moved from U.S. bank holding company swaps dealers and their U.S. affiliates to their newly deguaranteed foreign affiliates where Dodd- Frank swaps regulation is not being followed. However, what has not moved abroad is the very real obligation of the lender of last resort to rescue these U.S. swaps dealer bank holding companies if they fail because of poorly regulated swaps in their deguaranteed foreign subsidiaries, i.e., the U.S. taxpayer. While relief is unlikely to be forthcoming from the Trump Administration or the Republican-controlled Senate, some other means will have to be found to avert another multi-trillion-dollar bank bailout and/or a financial calamity caused by poorly regulated swaps on the books of big U.S. banks. This paper notes that the relevant statutory framework affords state attorneys general and state financial regulators the right to bring so-called âparens patriaeâ actions in federal district court to enforce, inter alia, Dodd- Frank on behalf of a stateâs citizens. That kind of litigation to enforce the statuteâs extraterritorial provisions is now badly needed
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