The Cretaceous-Paleogene boundary deposit in the Gulf of Mexico : oceanic basin response to the Chicxulub impact and geomechanics of reservoir-scale sand injectites, Panoche Hills, California

Hydrocarbon exploration in the last decade has yielded sufficient data to evaluate the Gulf of Mexico basin response to the Chicxulub asteroid impact. Given its passive marine setting and proximity to the impact structure on the Yucatán Peninsula, the Gulf is the premier locale in which to study the near-field geologic effect of a massive bolide impact. We mapped a thick (dm- to hm-scale) deposit of carbonate debris at the Cretaceous-Paleogene boundary that is ubiquitous in the Gulf and readily identifiable on borehole and seismic data. We interpret deposits seen in seismic and borehole data in the distal deepwater Gulf to be predominately muddy debrites with minor turbidites based on cores in the southeastern Gulf. Mapping of the deposit in the northern Gulf of Mexico reveals that the impact redistributed roughly 1.05 x 10⁵ km³ of sediment therein, and over 1.98 x 10⁵ km³ Gulf-wide. Deposit distribution suggests that the majority of sediment derived from coastal and shallow-water environments throughout the Gulf via seismic and megatsunamic processes initiated by the impact. The Texas shelf and northern margin of the Florida Platform were primary sources of sediment, while the central and southern Florida Platform underwent more localized platform collapse. Crustal structure of the ancestral Gulf influenced post-impact deposition both directly and indirectly through its control on salt distribution in the Louann salt basin. Nevertheless, impact-generated deposition overwhelmed virtually all topography and depositional systems at the start of the Cenozoic, blanketing the Gulf with carbonate debris within days. The Panoche Giant Injection Complex (PGIC) in central California is a complete injectite system. We measured hundreds of injectites over ~600 m of stratigraphic thickness in two locales in order to determine geomechanical controls on injection. We document an injectite architecture in the PGIC that we interpret to reflect a reversal in paleostress state from reverse to strike-slip or normal with proximity to the paleoseafloor. We demonstrate that injectite aperture and bulk strain decrease with distance from the injection source. We model this behavior with three hydraulic fracture geometries and conclude that injectites formed via radially propagating hydraulic fractures. We document a northeast-southwest paleo-orientation preference of subvertical injectites, which reflects the control of Farallon plate subduction on stress state at the PGIC. We estimate that the PGIC was complete and active for ~1 Ma and punctuated by ~20–150 ky-long periods of quiescence based on thickness and spacing of extrudites in the PGIC.Geological Science

Switchgrass (Panicum virgatum L.) polyubiquitin gene (PvUbi1 and PvUbi2) promoters for use in plant transformation

<p>Abstract</p> <p>Background</p> <p>The ubiquitin protein is present in all eukaryotic cells and promoters from ubiquitin genes are good candidates to regulate the constitutive expression of transgenes in plants. Therefore, two switchgrass (<it>Panicum virgatum </it>L.) ubiquitin genes (<it>PvUbi1 </it>and <it>PvUbi2</it>) were cloned and characterized. Reporter constructs were produced containing the isolated 5' upstream regulatory regions of the coding sequences (i.e. <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters) fused to the <it>uidA </it>coding region (<it>GUS</it>) and tested for transient and stable expression in a variety of plant species and tissues.</p> <p>Results</p> <p><it>PvUbi1 </it>consists of 607 bp containing <it>cis</it>-acting regulatory elements, a 5' untranslated region (UTR) containing a 93 bp non-coding exon and a 1291 bp intron, and a 918 bp open reading frame (ORF) that encodes four tandem, head -to-tail ubiquitin monomer repeats followed by a 191 bp 3' UTR. <it>PvUbi2 </it>consists of 692 bp containing <it>cis</it>-acting regulatory elements, a 5' UTR containing a 97 bp non-coding exon and a 1072 bp intron, a 1146 bp ORF that encodes five tandem ubiquitin monomer repeats and a 183 bp 3' UTR. <it>PvUbi1 </it>and <it>PvUbi2 </it>were expressed in all examined switchgrass tissues as measured by qRT-PCR. Using biolistic bombardment, <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters showed strong expression in switchgrass and rice callus, equaling or surpassing the expression levels of the CaMV <it>35S, 2x35S, ZmUbi1</it>, and <it>OsAct1 </it>promoters. GUS staining following stable transformation in rice demonstrated that the <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters drove expression in all examined tissues. When stably transformed into tobacco (<it>Nicotiana tabacum</it>), the <it>PvUbi2+3 </it>and <it>PvUbi2+9 </it>promoter fusion variants showed expression in vascular and reproductive tissues.</p> <p>Conclusions</p> <p>The <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters drive expression in switchgrass, rice and tobacco and are strong constitutive promoter candidates that will be useful in genetic transformation of monocots and dicots.</p

Extrinsic Rewards and Intrinsic Motives: Standard and Behavioral Approaches to Agency and Labor Markets

Employers structure pay and employment relationships to mitigate agency problems. A large literature in economics documents how the resolution of these problems shapes personnel policies and labor markets. For the most part, the study of agency in employment relationships relies on highly stylized assumptions regarding human motivation, e.g., that employees seek to earn as much money as possible with minimal effort. In this essay, we explore the consequences of introducing behavioral complexity and realism into models of agency within organizations. Specifically, we assess the insights gained by allowing employees to be guided by such motivations as the desire to compare favorably to others, the aspiration to contribute to intrinsically worthwhile goals, and the inclination to reciprocate generosity or exact retribution for perceived wrongs. More provocatively, from the standpoint of standard economics, we also consider the possibility that people are driven, in ways that may be opaque even to themselves, by the desire to earn social esteem or to shape and reinforce identity

Market Liquidity, Investor Participation and Managerial Autonomy: Why Do Firms Go Private?

We analyze a publicly-traded firm's decision to stay public or go private when managerial autonomy from shareholder intervention affects the supply of productive inputs by management. We show that both the advantage and the disadvantage of public ownership relative to private ownership lie in the liquidity of public ownership. While the liquidity of public ownership lets shareholders trade easily and supply capital at a lower cost, the liquidity-engendered trading also results in stochastic shocks to a firm's shareholder base. This exposes management to uncertainty regarding the identity of future shareholders and their extent of intervention in management decisions and in turn curtails managerial incentives. By contrast, because of its illiquidity, private ownership provides a stable shareholder base and improves these inputprovision incentives but results in a higher cost of capital. Thus, capital market liquidity, while being a principal advantage of public ownership, also has a surprising 'dark side' that discourages public ownership. Our model takes seriously a key difference between private and public equity markets in that, unlike the private market, the firm's shareholder base, namely the extent of investor participation, is stochastic in the public market. This allows us to extract predictions about the effects of investor participation on the stock price level and volatility and on the public firm's incentives to go private, thereby providing a link between investor participation and firm participation in public markets. Lesser investor participation induces lower and more volatile stock prices, encouraging public firms to go private, whereas greater investor participation encourages younger firms to go public. Moreover, IPO underpricing is optimal because it is shown to lead to a higher and less volatile post-IPO stock price, greater autonomy for the manager and a higher supply of privately-costly managerial inputs

Updates in SJS/TEN: collaboration, innovation, and community

Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN) is a predominantly drug-induced disease, with a mortality rate of 15–20%, that engages the expertise of multiple disciplines: dermatology, allergy, immunology, clinical pharmacology, burn surgery, ophthalmology, urogynecology, and psychiatry. SJS/TEN has an incidence of 1–5/million persons per year in the United States, with even higher rates globally. One of the challenges of SJS/TEN has been developing the research infrastructure and coordination to answer questions capable of transforming clinical care and leading to improved patient outcomes. SJS/TEN 2021, the third research meeting of its kind, was held as a virtual meeting on August 28–29, 2021. The meeting brought together 428 international scientists, in addition to a community of 140 SJS/TEN survivors and family members. The goal of the meeting was to brainstorm strategies to support the continued growth of an international SJS/TEN research network, bridging science and the community. The community workshop section of the meeting focused on eight primary themes: mental health, eye care, SJS/TEN in children, non-drug induced SJS/TEN, long-term health complications, new advances in mechanisms and basic science, managing long-term scarring, considerations for skin of color, and COVID-19 vaccines. The meeting featured several important updates and identified areas of unmet research and clinical need that will be highlighted in this white paper