cssi/SciSciGPT-SciSciNet huggingface dataset:
What to do in the event of an adverse anaesthetic event or medical error

Based on the principles of safe and patient-centred medical care, what would I want, if I, or a member of my family, was harmed during medical treatment? What is the right thing to do?
Understanding the sources of spatial disparity and convergence : evidence from Bangladesh

This paper utilizes the mixed effects model to measure and decompose spatial disparity in per capita expenditure in Bangladesh between 2000 and 2010. It finds a significant decline in spatial disparity in urban areas and the country as a whole but no substantial change in rural areas. The decomposition analysis indicates that average years of education, the percentage of households with electricity connections, and phone ownership account for most of the spatial variations in welfare. Spatial convergence in urban areas can be explained primarily by the expansion of electricity and phone networks for household use. Improved access to these services had little effect on spatial disparity in rural areas. This paper offers several explanations for the difference in convergence rates between urban and rural areas.
Only accessible information is useful: insights from gradient-mediated patterning

Information theory is gaining popularity as a tool to characterize performance of biological systems. However, information is commonly quantified without reference to whether or how a system could extract and use it; as a result, information-theoretic quantities are easily misinterpreted. Here, we take the example of pattern-forming developmental systems which are commonly structured as cascades of sequential gene expression steps. Such a multi-tiered structure appears to constitute sub-optimal use of the positional information provided by the input morphogen because noise is added at each tier. However, one must distinguish between the total information in a morphogen and information that can be usefully extracted and interpreted by downstream elements. We demonstrate that quantifying the information that is accessible to the system naturally explains the prevalence of multi-tiered network architectures as a consequence of the noise inherent to the control of gene expression. We support our argument with empirical observations from patterning along the major body axis of the fruit fly embryo. We use this example to highlight the limitations of the standard information-theoretic characterization of biological signalling, which are frequently de-emphasized, and illustrate how they can be resolved.
Optical Spectra of Supernovae

Supernova flux and polarization spectra bring vital information on the geometry, physical conditions, and composition structure of the ejected matter. For some supernovae the circumstellar matter is also probed by the observed spectra. Some of this information can be inferred directly from the observed line profiles and fluxes but, because of the Doppler broadening and severe line blending, interpretation often involves the use of synthetic spectra. The emphasis in this chapter is on recent results obtained with the help of synthetic spectra.
Noise-robust detection and tracking of salt domes in postmigrated volumes using texture, tensors, and subspace learning

ABSTRACTThe identification of salt-dome boundaries in migrated seismic data volumes is important for locating petroleum reservoirs. The presence of noise in the data makes computer-aided salt-dome interpretation even more challenging. We have developed noise-robust algorithms that could label boundaries of salt domes effectively and efficiently. Our research is twofold. First, we used a texture-based gradient to accomplish salt-dome detection. We found that by using a dissimilarity measure based on the 2D discrete Fourier transform, the algorithm was capable of efficiently detecting salt-dome boundaries with accuracy. At the same time, our analysis determined that the proposed algorithm was robust to noise. Once the detection is performed for an initial 2D seismic section, we track the initial boundaries through the data volume to accomplish an efficient labeling process by avoiding the parameter tuning that would have been necessary if detection had been performed for every seismic section. The tracking ...
ON THE DUAL NATURE OF CHANCE IN EVOLUTIONARY BIOLOGY AND PALEOBIOLOGY

The identification of randomness and nonrandomness is a perennial problem in evolu- tionary research. Stochastic thinking in evolutionary biology and paleobiology has solidified the use of a statistical notion of chance, but the idea of chance in evolutionary studies goes beyond statistics. A duality arises from the use of a statistical meaning on the one hand, and a more strictly evolutionary meaning on the other. The former implies a combination of indiscriminate sampling and unpredictability due to multiple causes; the latter codifies independence from adaptation and the directionality imposed by natural selection. Often these meanings are kept separate in evolu- tionary research, used in isolation according to the empirical situation or the goal of the investigator (recognition of pattern versus process). I argue that evolutionary studies in general and paleobi- ological studies in particular can benefit from the simultaneous application of statistical and evo- lutionary notions of chance. Following some background on the notion of chance and its use, I dis- cuss a series of examples in which insight can be gained by explicit consideration of both meanings. Thus, typologies of extinction become clearer when phenomena like wanton extinction are made explicit; exaptive radiations are exposed as an alternative to adaptive radiations; the possible non- adaptive nature of deterministic chaos becomes sensible; the nonrandomness of community-assem- bly is put into question; parallel taxonomies of sorting rooted in different notions of nonrandom- ness are suggested as a means of facilitating understanding of relationships across the hierarchy; developmental constraints and self-organization are more easily distinguished from selective con- straints; and a new term, "incidentals," is suggested to refer to both exaptations and nonaptations. Finally, I point to ways in which the dichotomy between chance and necessity can be approached in evolutionary theory, by showing that the dual nature of chance in evolution entails a distinction between functional and structural necessity, and that chance ultimately becomes a unifying concept for a number of criticisms to neo-Darwinism.
WISE-2005 tutorial: web content mining

Web mining aims to develop a new generation of techniques to effectively mine useful information or knowledge from the Web. It consists of Web usage mining, Web structure mining, and Web content mining. Web usage mining refers to the discovery of user access patterns from Web usage logs. Web structure mining tries to discover useful knowledge from the structure of Web hyperlinks. Web content mining aims to extract and mine useful information or knowledge from Web page contents. This tutorial focuses on Web Content Mining. In the past few years, there was a rapid expansion of activities in this area. In this tutorial, I will introduce the main web content mining tasks and problems and state-of-the-art techniques for dealing with them. All parts of the tutorial have a mix of research and industry flavor, addressing seminal research concepts and looking at the technology from an industry angle.
On Simplex Pivoting Rules and Complexity Theory

We show that there are simplex pivoting rules for which it is PSPACE-complete to tell if a particular basis will appear on the algorithm’s path. Such rules cannot be the basis of a strongly polynomial algorithm, unless P = PSPACE. We conjecture that the same can be shown for most known variants of the simplex method. However, we also point out that Dantzig’s shadow vertex algorithm has a polynomial path problem. Finally, we discuss in the same context randomized pivoting rules.
Green's Function Methods

The Greens function method is a powerful techniques for solving boundary value problems. Greens function was named after George Green (17931841), who developed a general method to obtain solutions of Poissons equation in potential theory. This method was described in an essay by Green entitled “On the application of mathematical analysis to the theories of electricity and magnetism,” published in 1828. Keywords: Green's function; delta function; eigenfunction; dyad
In vivo robotics: the automation of neuroscience and other intact-system biological fields

Robotic and automation technologies have played a huge role in in vitro biological science, having proved critical for scientific endeavors such as genome sequencing and high-throughput screening. Robotic and automation strategies are beginning to play a greater role in in vivo and in situ sciences, especially when it comes to the difficult in vivo experiments required for understanding the neural mechanisms of behavior and disease. In this perspective, we discuss the prospects for robotics and automation to influence neuroscientific and intact-system biology fields. We discuss how robotic innovations might be created to open up new frontiers in basic and applied neuroscience and present a concrete example with our recent automation of in vivo whole-cell patch clamp electrophysiology of neurons in the living mouse brain.
Efficient object localization using Convolutional Networks

Recent state-of-the-art performance on human-body pose estimation has been achieved with Deep Convolutional Networks (ConvNets). Traditional ConvNet architectures include pooling and sub-sampling layers which reduce computational requirements, introduce invariance and prevent over-training. These benefits of pooling come at the cost of reduced localization accuracy. We introduce a novel architecture which includes an efficient ‘position refinement’ model that is trained to estimate the joint offset location within a small region of the image. This refinement model is jointly trained in cascade with a state-of-the-art ConvNet model [21] to achieve improved accuracy in human joint location estimation. We show that the variance of our detector approaches the variance of human annotations on the FLIC [20] dataset and outperforms all existing approaches on the MPII-human-pose dataset [1].
Response to a population bottleneck can be used to infer recessive selection

Here we present the first genome wide statistical test for recessive selection. This test uses explicitly non-equilibrium demographic differences between populations to infer the mode of selection. By analyzing the transient response to a population bottleneck and subsequent re-expansion, we qualitatively distinguish between alleles under additive and recessive selection. We analyze the response of the average number of deleterious mutations per haploid individual and describe time dependence of this quantity. We introduce a statistic, BR, to compare the number of mutations in different populations and detail its functional dependence on the strength of selection and the intensity of the population bottleneck. This test can be used to detect the predominant mode of selection on the genome wide or regional level, as well as among a sufficiently large set of medically or functionally relevant alleles.
Biological Evaluation of Proteins

Publisher Summary Dietary proteins, through digestion in the gastrointestinal tract, furnish amino acids and polypeptides, which are the raw materials needed to build the body proteins of animals. These body proteins essentially form the matrix of the living system; the centers around which the dynamic equilibria of life develop. This chapter focuses on the biological evaluation of these proteins. The biological value of a protein refers to the amount of nitrogen retained in the body of an animal. A new phase of research on the nutritive value of proteins includes mixtures of amino acids replacing proteins. The pattern of essential amino acids varies with the physiological state of the animal and with the species. The retention of nitrogen in the animal is a function of this pattern. The simplest method used to evaluate nitrogen retention in an animal is to determine the difference between nitrogen intake and nitrogen excreted. This difference, called nitrogen balance, shows whether an animal is maintaining, losing, or gaining nitrogen. Correlations between the nutritive value of a protein and the amino acid composition can be excellent, when the composition represents the pattern of amino acids, which are absorbed into the animal. Along with the evaluation through nitrogen balance, evaluation of proteins through growth and tissue regeneration is also presented.
Using a radial, switchable, sector ground screen to produce azimuthal directivity for a monopole antenna

Ground-mounted monopole antennas are usually driven against a radial-wire ground system to control the input impedance and to improve the radiation efficiency. This results in a radiation pattern that is uniform in azimuth angle with a front-to-back ratio of 1, or 0 dB.
Direct estimation of evoked hemoglobin changes by multimodality fusion imaging

In the last two decades, both diffuse optical tomography DOT and blood oxygen level dependent BOLD-based functional magnetic resonance imaging fMRI methods have been developed as noninvasive tools for imaging evoked cerebral hemodynamic changes in studies of brain activity. Although these two technologies measure functional contrast from similar physiological sources, i.e., changes in hemoglobin levels, these two modalities are based on distinct physi- cal and biophysical principles leading to both limitations and strengths to each method. In this work, we describe a unified linear model to combine the complimentary spatial, temporal, and spectro- scopic resolutions of concurrently measured optical tomography and fMRI signals. Using numerical simulations, we demonstrate that con- current optical and BOLD measurements can be used to create cross- calibrated estimates of absolute micromolar deoxyhemoglobin changes. We apply this new analysis tool to experimental data ac- quired simultaneously with both DOT and BOLD imaging during a motor task, demonstrate the ability to more robustly estimate hemo- globin changes in comparison to DOT alone, and show how this approach can provide cross-calibrated estimates of hemoglobin changes. Using this multimodal method, we estimate the calibration of the 3 tesla BOLD signal to be 0.55% ±0.40% signal change per micromolar change of deoxyhemoglobin.
Experimental signatures of non-standard pre-BBN cosmologies

If detected, dark matter particles such as WIMPs and sterile neutrinos will be the earliest relics we can study, the first coming from before Big Bang Nucleosynthesis, an epoch from which we have no data so far. Here we discuss how different pre-BBN cosmological models affect the properties of these particles, and how these properties could thus allow to determine the evolution of the Universe before BBN.
Relating STM, ARPES, and transport in the cuprate superconducting state

We discuss a wealth of data from various types of experiments which together suggest that the superconducting state of optimally to over-doped BSCCO-2212 can be well-described by the BCS theory with a d-wave gap together with small-angle scattering from out-of-plane defects. These include scanning tunnelling Fourier transform spectroscopy observation of nanoscale inhomogeneity in the local gap edge position, the narrowing of the antinodal ARPES spectrum when BSCCO becomes superconducting, as well as the behavior of the microwave and thermal conductivities. We suggest that the large amount of small-angle scattering in BSCCO can account for the differences between the superconducting properties of BSCCO and YBCO.
Co9S8 as a catalyst for electroreduction of O2: quantum chemistry predictions.

The slab band quantum computational approach in the Vienna ab initio simulation package (VASP) is used to calculate the adsorption energies of reactants, reaction intermediates, and products in O2 reduction and in water oxidation in acid on three crystallographic surfaces of pentlandite structure Co9S8. Reversible potentials for the reaction steps involving electron and proton transfer are determined by using the energies in a linear Gibbs free energy relationship. On the basis of these results, we find that the partially OH-covered (202) surface is active toward O2 reduction and should have overpotential behavior similar to that observed for platinum electrodes. One structure in the predicted four-electron reduction mechanism is novel: S2- provides an adsorption site for O following O−O bond scission, which, unlike the case of platinum electrodes, takes place prior to the first reduction step.
The Role of Public, Relational and Organizational Trust in Economic Affairs

Trust, when established, contributes to the smooth running of political and economic systems which require the success of collective undertakings. Trust must be based on trustworthiness of the actors involved and the reliability of the institutions that are created to provide for the public good. Public trust is low when this is not the case. Even in the realm of business enterprises, market-based transactions, and the world of for-profit entities, trustworthiness and reliability build confidence in those who are the potential clients or consumers. In this paper, we discuss the role of trustworthiness in relations between physicians and their clients as one example of the role of public trust in professionals. We also discuss the role of trustworthiness in the realm of strategic alliances focusing on organizational culture and contractual safeguards as significant determinants of trust formation. We discuss the implications of this research and related work on the potential for increased trust at the relational, organizational and general societal levels in an ever-changing complex, global and interdependent world.
Face rings of simplicial complexes with singularities

The face ring of a simplicial complex modulo m generic linear forms is shown to have finite local cohomology if and only if the link of every face of dimension m or more is nonsingular, i.e., has the homology of a wedge of spheres of the expected dimension. This is derived from an enumerative result for local cohomology of face rings modulo generic linear forms, as compared with local cohomology of the face ring itself. The enumerative result is generalized to squarefree modules. A concept of Cohen–Macaulay in codimension c is defined and characterized for arbitrary finitely generated modules and coherent sheaves. For the face ring of an r-dimensional complex Δ, it is equivalent to nonsingularity of Δ in dimension r − c; for a coherent sheaf on projective space, this condition is shown to be equivalent to the same condition on any single generic hyperplane section. The characterization of nonsingularity in dimension m via finite local cohomology thus generalizes from face rings to arbitrary graded modules.
Upper tails for triangles

With ξ the number of triangles in the usual (Erdős-Renyi) random graph G(m,p), p > 1/m and η > 0, we show (for some Cη > 0) \documentclass{article} \usepackage{mathrsfs} \usepackage{amsmath, amssymb} \pagestyle{empty} \begin{document}\begin{align*} \text {Pr}(\xi > (1+\eta){{\sf E}} \xi) < \exp\lbrack -C_{\eta}\min\{ m^2p^2\log(1/p),m^3p^3\}\rbrack.\end{align*} \end{document} This is tight up to the value of Cη. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 40, 452–459, 2012 © 2012 Wiley Periodicals, Inc.
Regiospecific synthesis of mono- or diacetylated polyethylenepolyamine derivatives

Abstract Acetylated polyethylenepolyamines CH3CONHCH2(CH2-NH-CH2)CH2NH2 (n=1,2;) were synthesized using α-D-pentaacetyl-glucose as an acetylating agent.
Bethe ansatz for QCD pomeron

The equivalence is found between high–energy QCD in the generalized leading logarithmic approximation and the one-dimensional Heisenberg magnet. According to Regge theory, the high energy asymptotics of hadronic scattering amplitudes are related to singularities of partial waves in the complex angular momentum plane. In QCD, the partial waves are determined by nontrivial two-dimensional dynamics of the transverse gluonic degrees of freedom. The “bare” gluons interact with each other to form a collective excitation, the Reggeon. The partial waves of the scattering amplitude satisfy the BetheSalpeter equation whose solutions describe the color singlet compound states of Reggeons – Pomeron, Odderon and higher Reggeon states. We show that the QCD Hamiltonian for reggeized gluons coincides in the multi–color limit with the Hamiltonian of XXX Heisenberg magnet for spin s = 0 and spin operators the generators of the conformal SL(2,C) group. As a result, the Schrodinger equation for the compound states of Reggeons has a sufficient number of conservation laws to be completely integrable. A generalized Bethe ansatz is developed for the diagonalization of the QCD Hamiltonian and for the calculation of hadron-hadron scattering. Using the Bethe Ansatz solution of high–energy QCD we investigate the properties of the Reggeon compound states which govern the Regge behavior of the total hadron-hadron cross sections and the small−x behavior of the structure functions of deep inelastic scattering.
C–H Bond Functionalization with the Formation of a C–C Bond: A Free Radical Condensation Reaction Based on the Phthalimido‐N‐oxyl Radical

The development of a new chemical process that effects the conversion RH + C=C–C–X → R–C–C=C + HX, in which X is the phthalimido-N-oxyl radical (PINO·), is reported. The reaction yields are high, mass balances are excellent, and C–H bond functionalization and C–C bond formation are achieved in a single transformation. The byproduct of the reaction, N-hydroxyphthalimide, precipitates from solution and can be easily removed by simple filtration (and recycled). The kinetic chain lengths are shorter and the reaction times are longer (relative to those of the analogous reactions of allyl bromides), most likely because PINO· is a less-reactive hydrogen-atom abstractor. There appears to be no significant difference in efficiency in the addition–elimination steps. Competition experiments reveal that Br· and PINO· are comparable in leaving group ability.
Immigration and housing rents in American cities

Is there a local economic impact of immigration? Immigration pushes up rents and housing values in US destination cities. The positive association of rent growth and immigrant inflows is pervasive in time series for all metropolitan areas. I use instrumental variables based on a “shift-share” of national levels of immigration into metropolitan areas. An immigration inflow equal to 1% of a city’s population is associated with increases in average rents and housing values of about 1%. The results suggest an economic impact that is an order of magnitude bigger than that found in labor markets.
Simplified Solution of the Compressible Lifting Surface Problem

A simplified application of planar lifting-surface theory is presented for determining the load (distribution on finite wings in compressible subsonic flow. Classical theoretical forms are used to define functions for the pressure coefficient distribution. The Kernel function integral is evaluated in a closed form/finite summation manner, resulting in a well-behaved coefficient matrix similar to that obtained in vortex lattice theory. The Mangier-type singularity is avoided. Chordwise and spanwise integrals for lift and induced drag are reduced to simple summation, with the number of terms equal to the number of collocation points used. Analytical results are compared with experimental data and with other methods; quick convergence and computational efficiency are illustrated. b c c ccd
Configuration spaces and the space of rational curves on a toric variety

The space of holomorphic maps from $S^2$ to a complex algebraic variety $X$, i.e. the space of parametrized rational curves on $X$, arises in several areas of geometry. It is a well known problem to determine an integer $n(D)$ such that the inclusion of this space in the corresponding space of continuous maps induces isomorphisms of homotopy groups up to dimension $n(D)$, where $D$ denotes the homotopy class of the maps. The solution to this problem is known for an important but special class of varieties, the generalized flag manifolds: such an integer may be computed, and $n(D)\to\infty$ as $D\to\infty$. We consider the problem for another class of varieties, namely, toric varieties. For smooth toric varieties and certain singular ones, $n(D)$ may be computed, and $n(D)\to\infty$ as $D\to\infty$. For other singular toric varieties, however, it turns out that $n(D)$ cannot always be made arbitrarily large by a suitable choice of $D$.
Factorization problem on the Hilbert‐Schmidt group and the Camassa‐Holm equation

In this paper we solve the Camassa-Holm equation for a relatively large class of initial data by using a factorization problem on the Hilbert-Schmidt group. © 2007 Wiley Periodicals, Inc.
A computability theoretic equivalent to Vaught’s conjecture

We prove that, for every theory T which is given by anL!1;! sentence, T has less than 2 @ 0 many countable models if and only if we have that, for every X2 2 ! on a cone of Turing degrees, every X-hyperarithmetic model of T has an X-computable copy. We also nd a concrete description, relative to some oracle, of the Turing-degree spectra of all the models of a counterexample to Vaught's conjecture.
A Formal [3 + 3] Cycloaddition Approach to Natural-Product Synthesis

A formal [3 + 3] cycloaddition strategy for constructing complex heterocycles is reviewed here. This formal cycloaddition involves condensation of α,β-unsaturated iminium salts with 1,3-dicarbonyl equivalents. These reactions consist of a Knoevenagel-type condensation followed by a reversible 6π-electron electrocyclic ring-closure. They constitute a stepwise formal [3 + 3] cycloaddition protocol with the net result being the formation of two σ-bonds in addition to a new stereocenter adjacent to the heteroatom. This review describes in some detail, but not comprehensively, some precedents, problems, solutions, and stereochemical mechanistic issues, and focuses on applications of this formal cycloaddition strategy in natural product synthesis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Bonus symmetries of N = 4 super-Yang-Mills correlation functions via AdS duality

General conjectures about the SL(2,cZ) modular transformation properties of N = 4 superYang-Mills correlation functions are presented. It is shown how these modular transformation properties arise from the conjectured duality with IIB string theory on AdS5 × S5. We discuss in detail a prediction of the AdS duality: that N = 4 field theory, in an appropriate limit, must exhibit bonus symmetries, corresponding to the enhanced symmetries of IIB string theory in its supergravity limit.
Generalized classical BRST cohomology and reduction of Poisson manifolds

In this paper, we formulate a generalization of the classical BRST construction which applies to the case of the reduction of a Poisson manifold by a submanifold. In the case of symplectic reduction, our procedure generalizes the usual classical BRST construction which only applies to symplectic reduction of a symplectic manifold by a coisotropic submanifold, i.e. the case of reducible “first class” constraints. In particular, our procedure yields a method to deal with “second-class” constraints. We construct the BRST complex and compute its cohomology. BRST cohomology vanishes for negative dimension and is isomorphic as a Poisson algebra to the algebra of smooth functions on the reduced Poisson manifold in zero dimension. We then show that in the general case of reduction of Poisson manifolds, BRST cohomology cannot be identified with the cohomology of vertical differential forms.
Energy Analysis to the Design of Rotor-Bearing Systems

In the design of rotating machinery, it is often desirable and necessary to change a subset of system parameters to meet the design requirements. The success in designing rotor-bearing systems and in solving the vibration problems depends heavily upon the understanding of fundamental physical properties and insights of the systems. The modeling improvements and computational techniques have been extensively presented over the years. The design methodologies and fundamental properties have not been widely addressed to assist design engineers in solving their practical problems. The objective of this paper is to relate the various forms of energy and work and their contributions to the system dynamic characteristics. The design strategies and methodologies using the energy approach are also presented and illustrated in a turbine-driven machine.
Minimal discrepancies of toric singularities

The main purpose of this paper is to prove that minimal discrepancies ofn-dimensional toric singularities can accumulate only from above and only to minimal discrepancies of toric singularities of dimension less thann. I also prove that some lower-dimensional minimal discrepancies do appear as such limit.
THEORETICAL CONFIRMATION OF GA-STABILIZED ANTI-FERROMAGNETISM IN PLUTONIUM METAL

Density functional theory (DFT) for plutonium metal is shown to be consistent with recent magnetic measurements that suggest anti-ferromagnetism in Pu–Ga alloys at low temperatures. The theoretical model predicts a stabilization of the face-centered-cubic (fcc, δ) form of plutonium in an anti-ferromagnetic configuration when alloyed with gallium. The ordered magnetic phase occurs because Ga removes the mechanical instability that exists for unalloyed δ-Pu. The cause of the Ga-induced stabilization is a combination of a lowering of the band (kinetic) and electrostatic (Coulomb) energies for the cubic relative to the tetragonal phase. Similarly, gallium plays an important role in stabilizing anti-ferromagnetism in the tetragonal P4/mmm Pu3Ga compound.
Recent changes in Arctic Ocean sea ice motion associated with the North Atlantic Oscillation

Examination of a new ice motion dataset of the Arctic Ocean over a recent eighteen year period (1978-1996) reveals patterns of variability that can be linked directly to the North Atlantic Oscillation. The intensity of the Icelandic Low, one of its centers of action, modulates the sea level pressure distribution over a broad region of the Arctic Ocean and the Greenland-Iceland-Norwegian and Barents Seas. Over the winters of 1988 through 1995, the Oscillation has remained in its positive phase contributing to coherent large-scale changes in the intensity and character of ice transport in the Arctic Ocean. The significant changes include: the weakening of the Beaufort Gyre; the increase in ice export through the Fram Strait; the increase in ice import from the Barents/Kara Seas; the enhanced eastward transport of sea ice from the Laptev Sea; the weakening of the Transpolar Drift Stream; and, the reduction in ice extent in the Nordic Seas. All of these changes affect the regional and total sea ice mass balance of the Arctic Ocean.
One-pot three-step thioconjugate addition-oxidation-Diels–Alder reactions of ethyl propiolate

Ethyl propiolate undergoes one-pot three-step thioconjugate addition-oxidation-Diels–Alder cycloaddition when treated with a variety of thiols in the presence of catalytic base, meta-chloroperbenzoic acid, lithium perchlorate, and cyclopentadiene. The reaction of S-aryl thiols is catalyzed by trialkylamines, and the reaction of aliphatic thiols requires catalytic alkoxide base. Yields of the major diastereomer of the conveniently functionalized bicyclic products range from 47% to 81% depending upon the thiol reactant, which compares favorably to yields observed when the entire synthesis is performed step-by-step.
Self-paced brain-computer interface control of ambulation in a virtual reality environment.

Objective. Spinal cord injury (SCI) often leaves affected individuals unable to ambulate. Electroencephalogram (EEG) based brain–computer interface (BCI) controlled lower extremity prostheses may restore intuitive and able-body-like ambulation after SCI. To test its feasibility, the authors developed and tested a novel EEG-based, data-driven BCI system for intuitive and self-paced control of the ambulation of an avatar within a virtual reality environment (VRE). Approach. Eight able-bodied subjects and one with SCI underwent the following 10-min training session: subjects alternated between idling and walking kinaesthetic motor imageries (KMI) while their EEG were recorded and analysed to generate subject-specific decoding models. Subjects then performed a goal-oriented online task, repeated over five sessions, in which they utilized the KMI to control the linear ambulation of an avatar and make ten sequential stops at designated points within the VRE. Main results. The average offline training performance across subjects was 77.2±11.0%, ranging from 64.3% (p = 0.001 76) to 94.5% (p = 6.26×10−23), with chance performance being 50%. The average online performance was 8.5±1.1 (out of 10) successful stops and 303±53 s completion time (perfect = 211 s). All subjects achieved performances significantly different than those of random walk (p < 0.05) in 44 of the 45 online sessions. Significance. By using a data-driven machine learning approach to decode users’ KMI, this BCI–VRE system enabled intuitive and purposeful self-paced control of ambulation after only 10 minutes training. The ability to achieve such BCI control with minimal training indicates that the implementation of future BCI-lower extremity prosthesis systems may be feasible.
Phosphoramidite Gold(I)-Catalyzed Diastereo- and Enantioselective Synthesis of 3,4-Substituted Pyrrolidines

In this article the utility of phosphoramidite ligands in enantioselective AuI catalysis was explored in the development of highly diastereo- and enantioselective AuI-catalyzed cycloadditions of allenenes. A AuI-catalyzed synthesis of 3,4-disubstituted pyrrolidines and γ-lactams is described. This reaction proceeds through the enantioselective AuI-catalyzed cyclization of allenenes to form a carbocationic intermediate that is trapped by an exogenous nucleophile, resulting in the highly diastereoselective construction of three contiguous stereogenic centers. A computational study (DFT) was also performed to gain some insight into the underlying mechanisms of these cycloadditions. The utility of this new methodology was demonstrated through the formal synthesis of (−)-isocynometrine.
Influence of dust composition on cloud droplet formation

Abstract Previous studies suggest that interactions between dust particles and clouds are significant; yet the conditions where dust particles can serve as cloud condensation nuclei (CCN) are uncertain. Since major dust components are insoluble, the CCN activity of dust strongly depends on the presence of minor components. However, many minor components measured in dust particles are overlooked in cloud modeling studies. Some of these compounds are believed to be products of heterogeneous reactions involving carbonates. In this study, we calculate Kohler curves (modified for slightly soluble substances) for dust particles containing small amounts of K+, Mg2+, or Ca2+ compounds to estimate the conditions where reacted and unreacted dust can activate. We also use an adiabatic parcel model to evaluate the influence of dust particles on cloud properties via water competition. Based on their bulk solubilities, K+ compounds, MgSO4·7H2O, Mg(NO3)2·6H2O, and Ca(NO3)2·4H2O are classified as highly soluble substances, which enable activation of fine dust. Slightly soluble gypsum and MgSO3·6H2O, which may form via heterogeneous reactions involving carbonates, enable activation of particles with diameters between about 0.6 and 2 μm under some conditions. Dust particles>2 μm often activate regardless of their composition. Only under very specialized conditions does the addition of a dust distribution into a rising parcel containing fine (NH4)2SO4 particles significantly reduce the total number of activated particles via water competition. Effects of dust on cloud saturation and droplet number via water competition are generally smaller than those reported previously for sea salt. Large numbers of fine dust CCN can significantly enhance the number of activated particles under certain conditions. Improved representations of dust mineralogy and reactions in global aerosol models could improve predictions of the effects of aerosol on climate.
New Synthetic Technology for the Rapid Construction of Novel Heterocycles—Part 2. The Reaction of IBX with Anilides and Related Compounds

The unusual behavior of hypervalent iodine reagents, Dess - Martin periodinane and IBX, with an array of anilides leads to the formation of complex heterocycles in only one synthetic operation (see scheme). Furthermore, the substrates for these transformations are available in one step from readily available commercial building blocks. The mechanism by which these periodinanes interact with anilides is also explored. This exciting new class of chemical reactions was discovered during the course of the total synthesis of the CP molecules and leads to compounds which are relevant to chemical biology investigations and pharmaceutical research.
Effects of Rare Earth Oxide Addition on NdFeB Magnets

The effects of addition of rare-earth oxides on the magnetic properties of Nd-Fe-B sintered magnets are studied. The addition of Dy 2 O 3 and Tb 4 O 7 leads to an increase in intrinsic coercivity. For addition of Dy 2 O 3 , the optimum conditions for powder mixing and the optimum Dy 2 O 3 particle size were determined. A mixing time of more than 10 minutes, and a Dy 2 O 3 particle size of less than 3 ?m, are required to obtain a high intrinsic coercivity. EPMA measurements of NdFeBAl magnets with Dy 2 O 3 added reveal an inhomogeneous distribution of Dy in the Nd 2 Fe 14 B matrix: the material is Dy-rich near grain boundaries, but Dy-poor within the matrix. The appearance of such an inhomogeneous distribution of Dy is attributed to the reduction of Dy 2 O 3 in the Nd-rich phases, followed by diffusion of the resulting Dy atoms into the matrix.
Cosmological parameters from lensing power spectrum and bispectrum tomography

We examine how lensing tomography with the bispectrum and power spectrum can constrain cosmological parameters and the equation of state of dark energy. Our analysis uses the full information at the two- and three-point level from angular scales of a few degrees to 5 arcmin (50 ≤ l ≤ 3000), which will be probed by lensing surveys. We use all triangle configurations, cross-power spectra and bispectra constructed from up to three redshift bins with photometric redshifts, and all relevant covariances in our analysis. We find that the parameter constraints from bispectrum tomography are comparable to those from power spectrum tomography. Combining the two improves parameter accuracies by a factor of 3 due to their complementarity. For the dark energy parametrization w(a) = ω 0 + ω a (1 - a), the marginalized errors from lensing alone are σ(ω 0 ) ∼ 0.03f -1/2 sky and σ(ω a ) ∼ 0.1 f -1/2 sky. We show that these constraints can be further improved when combined with measurements of the cosmic microwave background or Type Ia supernovae. The amplitude and shape of the mass power spectrum are also shown to be precisely constrained. We use hyperextended perturbation theory to compute the non-linear lensing bispectrum for dark energy models. Accurate model predictions of the bispectrum in the moderately non-linear regime, calibrated with numerical simulations, will be needed to realize the parameter accuracy we have estimated. Finally, we estimate how well the lensing bispectrum can constrain a model with primordial non-Gaussianity.
Moving Observers in an Isotropic Universe

This paper considers how the motion of an observer in an isotropic universe may be determined by measurements. This provides a means to identify inertial frames, yielding a simple resolution to the twins paradox of relativity theory in such a universe. We propose that isotropy is a requirement for a frame to be inertial; this makes it possible to relate motion to the large scale structure of the universe.
Two rings in them all: The labdane-related diterpenoids

In his original exposition of the biogenetic isoprenoid rule, L. Ruzicka noted the structural identity between the fused A/B rings of triterpenoids/sterols and certain multicyclic diterpenoids as part of the impetus leading to that profound insight. His prescient hypothesis that this chemical structure relationship reflects similarities in the initial cyclization of these diterpenoids with that occurring in triterpenoid biosynthesis has since been verified. However, this chemical structure relationship does not continue to hold true for the additional rings found in many of these di- and tri- terpenoid natural products. This is now appreciated to arise from differences in their subsequent biogenesis, specifically further cyclization and/or rearrangement of these diterpenoids after formation of an initial bicyclic intermediate in a separately catalyzed reaction. The trivial name for the hydrocarbon skeleton of the most commonly found version of the corresponding unique intermediate forms the basis for a unifying “labdane-related” designation. This defines a large super-family of diterpenoids that contains nearly 7,000 already known natural products. Many of these are found in plants, where the requisite biosynthetic machinery for gibberellin phytohormones, particularly the relevant diterpene cyclases, provides a biosynthetic reservoir that appears to have been repeatedly drawn upon to evolve new labdane-related diterpenoids. The potent biological activity of the “ancestral” gibberellins, which has led to the independent evolution of distinct gibberellin biosynthetic pathways in plants, fungi, and bacteria, is further discussed as an archetypical example of the selective pressure driving the observed diversification of the large super-family of labdane-related diterpenoid natural products.
Chloroalkylation of aryl aldehydes using alkylboron dichlorides in the presence of oxygen

Abstract Reactions of aryl aldehydes with alkylboron dichlorides in the presence of oxygen at room temperature produces arylalkyl chlorides in good to excellent yields.
Family hierarchy and large neutrino mixings

Abstract The recent neutrino data seem to favor two large and one small mixing angles and a hierarchy of their squared mass differences. We discuss these within the context of hierarchical neutrino masses. We show that this scheme suggests a specific neutrino mass matrix with mild fine-tuning. We then present a Froggatt–Nielsen model that reproduces this matrix.
Image sharpening using image sequence and independent component analysis

The novel approach to the image sharpening problem is proposed in this paper. It is based on the application of the independent component analysis (ICA) algorithm on the image sequence with the appropriate time displacement between the image frames. The novelty is in the data representation required by the ICA algorithms where each selected image frame has been used as a sensor implying that underlying sources are temporally independent. The proposed concept enables blurring effects contributed by atmospheric turbulence to be extracted as separate physical sources. It has been ensured through images registration technique that motion of the video recorder is compensated. Encouraging preliminary results were obtained when ICA algorithm has been applied on the experimental data (video sequence) with the known ground truth. It has been verified that extracted spatial turbulence patterns are highly impulsive with Gaussian exponent between 0.5 and 0.6 where Laplacian distribution is characterized with Gaussian exponent 1.
Henoch-Schönlein purpura

Although Henoch-Schonlein purpura (HSP) can occur at any age from infancy to adulthood, it is overwhelmingly a disease of childhood. Indeed, HSP is the most common vasculitis syndrome affecting children. The clinical features of HSP have been well documented, and the diagnosis is generally not difficult. However, there are substantial gaps in our understanding of the etiology, pathogenesis, and treatment of HSP. This article briefly reviews the clinical aspects of HSP and new information concerning therapy. The major focus of this review is recent information concerning abnormalities of immunoglobulin A1 glycosylation and the role of aberrantly glycosylated immunoglobulin A1 in the pathogenesis of HSP.
Conformal geometrodynamics regained: Gravity from duality

There exist several ways of constructing general relativity from ‘first principles’: Einstein’s original derivation, Lovelock’s results concerning the exceptional nature of the Einstein tensor from a mathematical perspective, and Hojman–Kuchař-Teitelboim’s derivation of the Hamiltonian form of the theory from the symmetries of space–time, to name a few. Here I propose a different set of first principles to obtain general relativity in the canonical Hamiltonian framework without presupposing space–time in any way. I first require consistent propagation of scalar spatially covariant constraints (in the Dirac picture of constrained systems). I find that up to a certain order in derivatives (four spatial and two temporal), there are large families of such consistently propagated constraints. Then I look for pairs of such constraints that can gauge-fix each other and form a theory with two dynamical degrees of freedom per space point. This demand singles out the ADM Hamiltonian either in (i) CMC gauge, with arbitrary (finite, non-zero) speed of light, and an extra term linear in York time, or (ii) a gauge where the Hubble parameter is conformally harmonic.
On providing reliability guarantees in live video streaming with collaborative clients

Although many overlay and P2P approaches have been proposed to assist large-scale live video streaming, how to ensure service quality and reliability still remains a challenging issue. Peer dynamics, especially unscheduled node departures, affect the perceived video quality at a peer node in two ways. In particular, the amplitude of quality fluctuations and the duration for which stable quality video is available at a node heavily depend on the nature of peer departures in the system. In this paper, we first propose a service quality model to quantify the quality and stability of a video stream in a P2P streaming environment. Based on this model, we further develop tree construction algorithms that ensure that every peer in the collaborative network receives a video stream with a statistical reliability guarantee on quality. A key advantage of the proposed approach is that we can now explicitly control the quality and stability of the video stream supplied to every node. This is the fundamental difference of our approach from existing approaches that provide stream stability by over-provisioning resources allocated to every peer. Also, the proposed tree construction schemes decide the position of a node in the delivery tree based on both its estimated reliability and upstream bandwidth contribution while striving to minimize the overall load on the server. Our simulations show that our algorithms use the server resources very efficiently while significantly improving the video stability at peers.