High-Dimensional Fused Lasso Regression Using Majorization–Minimization and Parallel Processing

In this article, we propose a majorization–minimization (MM) algorithm for high-dimensional fused lasso regression (FLR) suitable for parallelization using graphics processing units (GPUs). The MM algorithm is stable and flexible as it can solve the FLR problems with various types of design matrices and penalty structures within a few tens of iterations. We also show that the convergence of the proposed algorithm is guaranteed. We conduct numerical studies to compare our algorithm with other existing algorithms, demonstrating that the proposed MM algorithm is competitive in many settings including the two-dimensional FLR with arbitrary design matrices. The merit of GPU parallelization is also exhibited. Supplementary materials are available online.     

Observation of the decay Omega(0)(c)-->Omega(-)e(+)nu(e)

Using the CLEO detector at the Cornell Electron Storage Ring we have observed the Omega(0)(c) (css ground state) in the decay Omega(0)(c)-->Omega(-)e(+)nu(e). We find a signal of 11.4+/-3.8(stat) events. The probability that we have observed a background fluctuation is 7.6x10(-5). We measure B(Omega(0)(c)-->Omega(-)e(+)nu(e)).sigma(e(+)e(-)-->Omega(0)(c)X)=(42.2+/-14.1(stat)+/-5.7(syst)) fb and R=[Gamma(Omega(0)(c)-->Omega(-)pi(+))]/[Gamma(Omega(0)(c)-->Omega(-)enu(e))]=00.41+/-0.19(stat)+/-0.04(syst). This is the first statistically significant observation of an individual decay mode of the Omega(0)(c) in e(+)e(-) annihilation and the first example of a baryon decaying via beta emission, where no quarks from the first generation participate in the reaction.     

Rate measurement of D(0)-->K+pi(-)pi(0) and constraints on D(0) -- D(0) mixing

We present an observation and time-integrated rate measurement of the decay D(0)-->K(+)pi(-)pi(0) produced in 9 fb(-1) of e(+)e(-) collisions near the Upsilon(4S) resonance. The signal is inconsistent with an upward fluctuation of the background by 4.9 standard deviations. We measured the time-integrated rate of D(0)-->K(+)pi(-)pi(0) normalized to the rate of D(0)-->K(+)pi(-)pi(0) to be 0.0043(+0.0011)(-0.0010) (stat)+/-0.0007 (syst). This decay can be produced by doubly Cabibbo-suppressed decays or by the D(0) evolving into a D(0) through mixing, followed by a Cabibbo-favored decay to K(+)pi(-)pi(0). We also found the CP asymmetry A = (9(+25)(-22))% be consistent with zero.     

Choline hydroxide: An efficient and biodegradable catalyst for the synthesis of 2-amino-3-nitro-4H-chromene derivatives in an aqueous medium

Abstract

An expedient, eco-friendly and efficient procedure for the synthesis of novel 2-amino-3-nitro-4H-chromene derivatives has been developed through the reaction of various 2-hydroxybenzaldehydes and (E)-N-methyl-1-(methylthio)-2-nitroethenamine in the presence of the basic ionic liquid catalyst (choline hydroxide (ChOH)) at room temperature an aqueous medium. The advantageous of this method is a biodegradable and recyclable catalyst, mild, environmentally friendly and high products yields (83-96%) in short reaction times.     

Humectants effect on aqueous fluids absorption of γ-irradiated PVA hydrogel followed by freeze thawing

To evaluate the effect of humectants such as glycerol, poly(vinyl alcohol)/glycerol (P/G) hydrogels were prepared by using γ-ray irradiation followed by freeze thawing (FT). The gel fraction ratio (G) and equilibrium swelling ratio (S) of the P/G hydrogels were investigated as functions of glycerol content and FT cycles. Interestingly, G increases while S decreases with increase in glycerol content. This result indicates that even if the glycerol is useful to improve the smoothness and moisture of the hydrogels, further consideration of conditioning the use of glycerol to improve the absorption of exudates from wounds for an advanced wound healing is needed.     

A New Perspective on Li–SO2 Batteries for Rechargeable Systems

Primary Li–SO₂ batteries offer a high energy density in a wide operating temperature range with exceptionally long shelf life and have thus been frequently used in military and aerospace applications. Although these batteries have never been demonstrated as a rechargeable system, herein, we show that the reversible formation of Li₂S₂O₄, the major discharge product of Li–SO₂ battery, is possible with a remarkably smaller charging polarization than that of a Li–O₂ battery without the use of catalysts. The rechargeable Li–SO₂ battery can deliver approximately 5400 mAh g^?1 at 3.1 V, which is slightly higher than the performance of a Li–O₂ battery. In addition, the Li–SO₂ battery can be operated with the aid of a redox mediator, exhibiting an overall polarization of less than 0.3 V, which results in one of the highest energy efficiencies achieved for Li–gas battery systems.     

Surface functionalization of multiwalled carbon nanotubes with poly(3,4-propylenedioxythiophene) and preparation of its random copolymers: new hybrid materials

Multiwalled carbon nanotubes (MWNTs) were functionalized with poly(3,4-propylenedioxythiophene) (PProDOT) using a simple “chemical grafting” approach. After the conventional acid oxidation (AO) process, the MWNT-COOH was converted to the acyl chloride functionalized MWNTs (MWNT-COCl) by treating them with thionyl chloride. The MWNT-COCl were further reacted with a functionalized monomer based on 3,4-propylenedioxythiophene (ProDOT-OH), followed by oxidative polymerization to prepare the MWNT-g-PProDOT hybrid. The monomer-functionalized MWNTs was further copolymerized with thiophene to prepare conducting copolymers on carbon nanotubes (CNTs). Fourier-transformed infrared spectrophotometry was employed to characterize the change in surface functionalities, which revealed that the PProDOT was covalently grafted to the MWNTs, while TGA was used to study the weight gain due to the functionalization. UV–Vis absorption spectra revealed the functionalization of the conjugated polymer by showing the typical absorption band. The morphology micrographs of the grafted PProDOT on MWNTs as evidenced by field emission scanning electron microscopy and transmission electron microscopy showed apparent effect on the structure and appearance of the MWNTs by growing thicker as expected from surface modification. Using the facile route developed in this study, CNTs can be easily fabricated with other types of polymers for several applications.     

Degradation behavior of poly (l-lactide-co-glycolide) films through gamma-ray irradiation

Gamma-ray irradiation is a very useful tool to improve the physicochemical properties of various biodegradable polymers without the use of a heating and crosslinking agent. The purpose of this study was to investigate the degradation behavior of poly (l-lactide-co-glycolide) (PLGA) depending on the applied gamma-ray irradiation doses. PLGA films prepared through a solvent casting method were irradiated with gamma radiation at various irradiation doses. The irradiation was performed using 60Co gamma-ray doses of 25–500 kGy at a dose rate of 10 kGy/h.The degradation of irradiated films was observed through the main chain scission. Exposure to gamma radiation dropped the average molecular weight (M_n and M_w), and weakened the mechanical strength. Thermograms of irradiated film show various changes of thermal properties in accordance with gamma-ray irradiation doses. Gamma-ray irradiation changes the morphology of the surface, and improves the wettability. In conclusion, gamma-ray irradiation will be a useful tool to control the rate of hydrolytic degradation of these PLGA films.     

A fast algorithm to sample the number of vertexes and the area of the random convex hull on the unit square

We propose an algorithm to sample the area of the smallest convex hull containing \(n\) sample points uniformly distributed over unit square. To do it, we introduce a new coordinate system for the position of vertexes and re-write joint distribution of the number of vertexes and their locations in the new coordinate system. The proposed algorithm is much faster than existing procedure and has a computational complexity on the order of \(O(T)\) , where \(T\) is the number of vertexes. Using the proposed algorithm, we numerically investigate the asymptotic behavior of functionals of the random convex hull. In addition, we apply it to finding pairs of stocks where the returns are dependent on each other on the New York Stock Exchange.