Enantioselective Synthesis of (+) and (–)-2-[1-(2,6-Dichlorophenoxy)-Ethyl]-1,3-Diazacyclopent-2-Ene

Methods for the enantioselective synthesis of (+) and (−) lofexidine or 2-[1-(2,6)-dichlorophenoxy)-ethyl]-1,3-diazacyclopent-2-ene involve converting (+) or (−) 1-methyl-1-[2,6-dichlorophenoxy]ethanamide to an (+) or (−) imino-ether intermediate by electrophilic attack of the amide oxygen by a trimethoxonium ion and, without isolation, converting the (+) or (−) imino-ether intermediate to (+) or (−) 2-[1-(2,6-dichlorophenoxy)-ethyl]1,3-diazacyclopent-2-ene by adding ethylene diamine; and optionally converting the (+) or (−) 2-[1-(2,6-dichlorophenoxy)-ethyl]1,3-diazacyclopent-2-ene into a pharmaceutically acceptable acid addition salt thereof

cis-2,5-Bis(2-fluoro-5-meth­oxy­pheneth­yl)pyrrolidinium formate

In the title compound, C22H28F2NO2 +·CHO2 −, there are three independent pyrrolidinium formate salt mol­ecules. In each cation, the central pyrrolidinium ring is not planar and the 2,5-disubstituted phenyl­ethyl groups are in equatorial positions. In the crystal, the ions are linked into a pair of chains parallel to the c axis by N—H⋯O hydrogen bonds between the NH group of the pyrrolidinium ring and the formate O atoms

Effects of Dietary Protein and Lipid Levels on Growth and Body Composition of Silver Dollar (Metynnis schreitmuelleri) Fry

Abstract The aims of this study were to determine the effects of different levels of protein and lipid on the growth and body composition of fry of the silver dollar, Metynnis schreitmuelleri (Ahl). The fry were first fed diets containing 25, 35, 45, or 55% protein to determine the optimum protein level. The best growth, body composition, protein efficiency ratio, and food conversion ratio were obtained with the 35% protein diet. The fry were next fed diets containing 35% protein and 0, 3, 6, 9, or 12% lipid. The best growth, body composition, protein efficiency ratio, and food conversion ratio occurred with the diet containing 35% protein and 6% lipid

Monte Carlo Study of Real Time Dynamics on the Lattice

Monte Carlo studies involving real time dynamics are severely restricted by the sign problem that emerges from a highly oscillatory phase of the path integral. In this Letter, we present a new method to compute real time quantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo simulations. The key idea is to deform the path integration domain to a complex manifold where the phase oscillations are mild and the sign problem is manageable. We use the previously introduced "contraction algorithm" to create a Markov chain on this alternative manifold. We substantiate our approach by analyzing the quantum mechanical anharmonic oscillator. Our results are in agreement with the exact ones obtained by diagonalization of the Hamiltonian. The method we introduce is generic and, in principle, applicable to quantum field theory albeit very slow. We discuss some possible improvements that should speed up the algorithm

Supervised Human-Guided Data Exploration

Peer reviewe

Vamsa: Automated Provenance Tracking in Data Science Scripts

There has recently been a lot of ongoing research in the areas of fairness, bias and explainability of machine learning (ML) models due to the self-evident or regulatory requirements of various ML applications. We make the following observation: All of these approaches require a robust understanding of the relationship between ML models and the data used to train them. In this work, we introduce the ML provenance tracking problem: the fundamental idea is to automatically track which columns in a dataset have been used to derive the features/labels of an ML model. We discuss the challenges in capturing such information in the context of Python, the most common language used by data scientists. We then present Vamsa, a modular system that extracts provenance from Python scripts without requiring any changes to the users' code. Using 26K real data science scripts, we verify the effectiveness of Vamsa in terms of coverage, and performance. We also evaluate Vamsa's accuracy on a smaller subset of manually labeled data. Our analysis shows that Vamsa's precision and recall range from 90.4% to 99.1% and its latency is in the order of milliseconds for average size scripts. Drawing from our experience in deploying ML models in production, we also present an example in which Vamsa helps automatically identify models that are affected by data corruption issues

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE