Market models with optimal arbitrage

We construct and study market models admitting optimal arbitrage. We say that a model admits optimal arbitrage if it is possible, in a zero-interest rate setting, starting with an initial wealth of 1 and using only positive portfolios, to superreplicate a constant c>1. The optimal arbitrage strategy is the strategy for which this constant has the highest possible value. Our definition of optimal arbitrage is similar to the one in Fernholz and Karatzas (2010), where optimal relative arbitrage with respect to the market portfolio is studied. In this work we present a systematic method to construct market models where the optimal arbitrage strategy exists and is known explicitly. We then develop several new examples of market models with arbitrage, which are based on economic agents' views concerning the impossibility of certain events rather than ad hoc constructions. We also explore the concept of fragility of arbitrage introduced in Guasoni and Rasonyi (2012), and provide new examples of arbitrage models which are not fragile in this sense

Exploring Historically Black College and Universities\u27 Ethos of Racial Uplift: Stem Students\u27 Challenges and Institutions\u27 Practices for Cultivating Learning and Persistence in Stem

Achievement in STEM (Science, Technology, Engineering and Mathematics) is a marker of racial inequality. Despite making up 13 percent of the U.S. populace, Black representation in STEM education and the STEM workforce is far from equitable. A reversal of this trend, however, exists at Historically Black Colleges and Universities (HBCUs), where HBCU graduates represent nearly 18 percent of STEM baccalaureate degrees awarded to Black students. Through a multi-site case study of STEM education at four HBCUs, I interviewed students, faculty and administrators involved in services and programs (i.e. undergraduate research, mentoring) specific to supporting students in the gateway courses. Validation Theory and Science Identity Theory were used to inform the overall design--collection and analysis of data--of the study. I found that these services make a meaningful difference in the achievement of students in STEM by providing them with sound relationships and effective study skills, embedded within a culture of family, that help them overcome the challenges associated with the gateway courses. This difference can also be attributed to the multiple roles that faculty plays outside the classroom to address the challenges that externally bear on their students\u27 achievement. By understanding how these four HBCUs have helped their students overcome this critical stage in the STEM educational pipeline, findings help identify salient practices and strategies that encourage minority student learning and persistence that could be informative to other minority serving institutions and majority institutions struggling to support these student populations. Lastly, this study also demonstrates the ongoing importance of HBCUs in improving minority access to opportunities in the STEM workforce

On the regularity of SLE trace

We revisit regularity of SLE trace, for all κ≠8, and establish Besov regularity under the usual half-space capacity parametrization. With an embedding theorem of Garsia–Rodemich–Rumsey type, we obtain finite moments (and hence almost surely) optimal variation regularity with index min(1+κ/8,2), improving on previous works of Werness, and also (optimal) Hölder regularity à la Johansson Viklund and Lawler

Rapid Organocatalytic Formation of Carbon Monoxide: Application towards Carbonylative Cross Couplings

Herein, the first organocatalytic method for the transformation of non‐derivatized formic acid into carbon monoxide (CO) is introduced. Formylpyrrolidine (FPyr) and trichlorotriazine (TCT), which is a cost‐efficient commodity chemical, enable this decarbonylation. Utilization of dimethylformamide (DMF) as solvent and catalyst even allows for a rapid CO generation at room temperature. Application towards four different carbonylative cross coupling protocols demonstrates the high synthetic utility and versatility of the new approach. Remarkably, this also comprehends a carbonylative Sonogashira reaction at room temperature employing intrinsically difficult electron‐deficient aryl iodides. Commercial 13C‐enriched formic acid facilitates the production of radiolabeled compounds as exemplified by the pharmaceutical Moclobemide. Finally, comparative experiments verified that the present method is highly superior to other protocols for the activation of carboxylic acids

Enucleated eyes after failed intra-arterial infusion of chemotherapy for unilateral retinoblastoma: histopathologic evaluation of vitreous seeding

Selective intra-arterial chemotherapy (IAC) has been adopted by many ocular oncology centers to treat advanced intraocular retinoblastoma. In this report, we describe two patients with unilateral intraocular retinoblastoma and persistent vitreous seeding, who were treated with IAC after failed systemic chemotherapy. Despite multiple sessions and increasing dosage of drug delivery, vitreous seeding in these cases failed to respond to IAC, and ultimately both eyes were enucleated for tumor control. Based on the histopathologic findings in these two cases, IAC appears to have limitations in treating persistent vitreous seeding in eyes which have failed systemic chemotherapy. Possible causes for failure of IAC to treat persistent vitreous seeding include poor vitreous penetration, inactive state of tumor seeds within the avascular vitreous cavity, and chemotherapeutic drug resistance