Null Reductions of M5-Branes

We perform a general reduction of an M5-brane on a spacetime that admits a null Killing vector, including couplings to background 4-form fluxes and possible twisting of the normal bundle. We give the non-abelian extension of this action and present its supersymmetry transformations. The result is a class of supersymmetric non-lorentzian gauge theories in 4+1 dimensions, which depend on the geometry of the six-dimensional spacetime. These can be used for DLCQ constructions of M5-branes reduced on various manifolds.Comment: 21 pages; more typos corrected and additional comment in the introduction, to appear in JHEP (hopefully

Development of a New Lewis Acid-Catalyzed [3,3]-Sigmatropic Rearrangement: The Allenoate-Claisen Rearrangement

A new Lewis acid-catalyzed Claisen rearrangement has been developed that allows the stereoselective construction of β-amino-α,β,ε,ζ-unsaturated-γ,δ-disubstituted esters from simple allylic amines and allenoate esters. This reaction, which is contingent upon the use of Lewis acid, can be conducted with a range of metal salts (Yb(OTf)_3, AlCl_3, Sn(OTf)_2, Cu(OTf)_2, MgBr_2·Et_2O, FeCl_3, Zn(OTf)2) with catalyst loadings as low as 5 mol %. This catalytic process provides access to a diverse range of β-amino-α,β,ε,ζ-unsaturated-γ,δ-disubstituted esters in high yield and with excellent levels of diastereoselectivity for a series of allyl pyrrolidines (R_1 = H, Me, i-Pr, Ph, NR_2 = pyrrolidine, piperidine, Nme_2; ≥81% yield, ≥94:6 syn:anti) and allenoate esters (R_2 = H, Me, i-Pr, Ph, allyl, NPht, Cl; ≥75% yield, ≥91:9 syn:anti). The capacity of this new Claisen rearrangement to provide catalytic access to elusive structural motifs has also been demonstrated in the stereospecific formation of quaternary carbon bearing frameworks arising from geranyl- and neryl pyrrolidine (≥93% yield, >98:2 dr)

Schumpeter, the Banking System, and Innovation: Small versus Big Business

Joseph Schumpeter’s writings on entrepreneurship and innovation have had a profound impact on economic theory and economic thought. Schumpeter initially saw the small entrepreneur as the source of innovation and economic growth within an economic system but later saw large corporations as the source of much innovation. Because large corporations, and in modern times many governments and universities as well, play such a large role in funding research and development and new innovations, much of the bank financing of innovation is done by smaller banks for small entrepreneurs and their ideas. Venture capitalists and self-financing are the other two major forms of small entrepreneur/small business financing. Meanwhile, the financial markets (stocks and bond markets) only indirectly play a role in funding the innovation of large corporations via changes in these firms’ stock prices. Changes in stock prices reflect an estimate of the large firms’ research and development efforts and their prospects for profitable, future innovation. Much corporate research and development is financed internally within the organization as an expense of doing business. Meanwhile, government and university funding through tax dollars and non-profit sources indirectly subsidize corporate innovation because governmental entities and universities take on risks that the private sector will often not tolerate. Yet, large corporations are often the beneficiaries of such governmental and university financing of research and development efforts. In today’s times, Schumpeter would be impressed with the success of large firms regarding innovation but probably would be disappointed about the marginalization of the small entrepreneurial firm and the banking system and their diminished roles in innovation. This paper summarizes Schumpeter’s views on how the banking system and financial markets could play a role in innovation and explains how a modern day monopoly capital system (Baran and Sweezy 1966) and its financial system have transformed entrepreneurship and innovation away from small business and innovation by the small entrepreneur. Baran, Paul A, and Paul M Sweezy. 1966. Monopoly Capital: An Essay on the American Economic and Social Order. New York: Monthly Review Press

Schumpeter, the Banking System, and Innovation: Small versus Big Business

Joseph Schumpeter’s writings on entrepreneurship and innovation have had a profound impact on economic theory and economic thought. Schumpeter initially saw the small entrepreneur as the source of innovation and economic growth within an economic system but later saw large corporations as the source of much innovation. Because large corporations, and in modern times many governments and universities as well, play such a large role in funding research and development and new innovations, much of the bank financing of innovation is done by smaller banks for small entrepreneurs and their ideas. Venture capitalists and self-financing are the other two major forms of small entrepreneur/small business financing. Meanwhile, the financial markets (stocks and bond markets) only indirectly play a role in funding the innovation of large corporations via changes in these firms’ stock prices. Changes in stock prices reflect an estimate of the large firms’ research and development efforts and their prospects for profitable, future innovation. Much corporate research and development is financed internally within the organization as an expense of doing business. Meanwhile, government and university funding through tax dollars and non-profit sources indirectly subsidize corporate innovation because governmental entities and universities take on risks that the private sector will often not tolerate. Yet, large corporations are often the beneficiaries of such governmental and university financing of research and development efforts. In today’s times, Schumpeter would be impressed with the success of large firms regarding innovation but probably would be disappointed about the marginalization of the small entrepreneurial firm and the banking system and their diminished roles in innovation. This paper summarizes Schumpeter’s views on how the banking system and financial markets could play a role in innovation and explains how a modern day monopoly capital system (Baran and Sweezy 1966) and its financial system have transformed entrepreneurship and innovation away from small business and innovation by the small entrepreneur. Baran, Paul A, and Paul M Sweezy. 1966. Monopoly Capital: An Essay on the American Economic and Social Order. New York: Monthly Review Press

Elasto-capillarity in insect fibrillar adhesion.

The manipulation of microscopic objects is challenging because of high adhesion forces, which render macroscopic gripping strategies unsuitable. Adhesive footpads of climbing insects could reveal principles relevant for micro-grippers, as they are able to attach and detach rapidly during locomotion. However, the underlying mechanisms are still not fully understood. In this work, we characterize the geometry and contact formation of the adhesive setae of dock beetles (Gastrophysa viridula) by interference reflection microscopy. We compare our experimental results to the model of an elastic beam loaded with capillary forces. Fitting the model to experimental data yielded not only estimates for seta adhesion and compliance in agreement with previous direct measurements, but also previously unknown parameters such as the volume of the fluid meniscus and the bending stiffness of the tip. In addition to confirming the primary role of surface tension for insect adhesion, our investigation reveals marked differences in geometry and compliance between the three main kinds of seta tips in leaf beetles

Measuring Data

We identify the task of measuring data to quantitatively characterize the composition of machine learning data and datasets. Similar to an object's height, width, and volume, data measurements quantify different attributes of data along common dimensions that support comparison. Several lines of research have proposed what we refer to as measurements, with differing terminology; we bring some of this work together, particularly in fields of computer vision and language, and build from it to motivate measuring data as a critical component of responsible AI development. Measuring data aids in systematically building and analyzing machine learning (ML) data towards specific goals and gaining better control of what modern ML systems will learn. We conclude with a discussion of the many avenues of future work, the limitations of data measurements, and how to leverage these measurement approaches in research and practice

The evolution of cyclopropenium ions into functional polyelectrolytes

Versatile polyelectrolytes with tunable physical properties have the potential to be transformative in applications such as energy storage, fuel cells and various electronic devices. Among the types of materials available for these applications, nanostructured cationic block copolyelectrolytes offer mechanical integrity and well-defined conducting paths for ionic transport. To date, most cationic polyelectrolytes bear charge formally localized on heteroatoms and lack broad modularity to tune their physical properties. To overcome these challenges, we describe herein the development of a new class of functional polyelectrolytes based on the aromatic cyclopropenium ion. We demonstrate the facile synthesis of a series of polymers and nanoparticles based on monomeric cyclopropenium building blocks incorporating various functional groups that affect physical properties. The materials exhibit high ionic conductivity and thermal stability due to the nature of the cationic moieties, thus rendering this class of new materials as an attractive alternative to develop ion-conducting membranes

Gonadotropin administration to mimic mini-puberty in hypogonadotropic males: pump or injections?

Objective: Newborns with congenital hypogonadotropic hypogonadism (CHH) have an impaired postnatal activation of the gonadotropic axis. Substitutive therapy with recombinant gonadotropins can be proposed to mimic physiological male mini-puberty during the first months of life. The aim of this study was to co mpare the clinical and biological efficacy of two treatment modalities of gonadotropins administration during mini-puberty in CHH neonates. Design: Multicenter retrospective analytical epidemiological study comparing two treatments, pump vs injection, between 2004 and 2019. Methods: Clinical (penile size, testis size, testicular descent) and biological parameters (serum concentrations of testosterone, anti-Müllerian hormone (AMH) and Inhibin B) were compared between the two groups by multivariate analyses. Results: Thirty-five patients were included. A significantly higher incre ase in penile length and testosterone level was observed in the injection group compared to the pump group (+0.16 ± 0.02 mm vs +0.10 ± 0.02 mm per day, P = 0.002; and +0.04 ± 0.007 ng/mL vs +0.01 ± 0.008 ng/mL per day, P = 0.001). In both groups, significant increases in penile length and width, testosterone, AMH, and Inhibin B levels were observed, as well as improved testicular descent (odds ratio of not being in a scrotal position at the end of treatment = 0.97 (0.96; 0.99)). Conclusions: Early postnatal administration of recombinant gonadotropins in CHH boys is effective in stimulating penile growth, Sertoli cell proliferati on, and testicular descent, with both treatment modalities