The Atomic and Electronic Structure of Liquid N- Methylformamide as Determined from Diffraction Experiments

The structure of liquid N-methylformamide (NMF) has been investigated using synchrotron radiation at 77 and 95 keV. The use of high energy photons has several advantages, in this case especially the large accessible momentum transfer range, the low absorption and the direct comparability with neutron diffraction. The range of momentum transfer covered is 0.6 \AA$^{-1} <$ Q $<$24.0 \AA$^{-1}$. Neutron diffraction data on the same sample in the same momentum transfer range have been published previously. In that study two differently isotope - substituted species were investigated. In order to compare neutron and photon diffraction data properly Reverse Monte Carlo (RMC-) simulations have been performed. Some modifications had to be added to the standard RMC- code introducing different constraints for inter- and intramolecular distances as these distances partly overlap in liquid NMF. RMC- simulations having only the neutron data as input were carried out in order to test the quality of the X-ray data. The photon structure factor calculated from the RMC- configurations is found to agree well with the present experimental data, while it deviates considerably from earlier X-ray work using low energy photons (17 keV). Finally we discuss whether the different interaction mechanisms of neutrons and photons can be used to directly access the electronic structure in the liquid. Evidence is presented that the elastic self scattering part of liquid NMF is changed with respect to the independent atom approximation. This modification can be accounted for by a simple charged atoms model.Comment: Accepted for publication in Molecular Physics, LaTex file, 12 pages, figures not include

An intermediate value theorem in ordered Banach spaces

We consider a monotone increasing operator in an ordered Banach space having $u_-$ and $u_+$ as a strong super- and subsolution, respectively. In contrast with the well studied case $u_+ < u_-$, we suppose that $u_- < u_+$. Under the assumption that the order cone is normal and minihedral, we prove the existence of a fixed point located in the ordered interval $[u_-,u_+].

Modulation of human JAK-STAT pathway signaling by functionally conserved regulators

Both the core JAK-STAT pathway components and their in vivo roles have been widely conserved between vertebrates and invertebrate models such as Drosophila melanogaster. Misregulation of JAK-STAT pathway activity has also been identified as a key factor in the development of multiple human malignancies. Recently, whole genome RNA interference (RNAi) screens in cultured Drosophila cells have identified both positively and negatively acting JAK-STAT pathway regulators. Here, we describe the analysis of 73 human genes representing homologs of 56 Drosophila genes originally identified by genome-wide RNAi screening as regulators of JAK-STAT signaling. Using assays for human STAT1 and STAT3 protein levels and phosphorylation status, as well as assays measuring the expression of endogenous STAT1 and STAT3 transcriptional targets, we have tested siRNAs targeting these 73 human genes and have identified potential JAK-STAT pathway regulatory roles in 69 (95%) of these. The genes identified represent a wide range of human JAK-STAT pathway regulators and include genes not previously known to modulate this signaling cascade. These results underline the value of model system based approaches for the identification of pathway regulators and have led to the identification of loci whose misregulation may ultimately be implicated in JAK-STAT pathway-mediated human disease

Петрология, геохимия и рудоносность анорогенных гранитоидов шибеликского комплекса Горного Алтая

Актуальность проведенных исследований определяется необходимостью изучения петрологии, геохимии и оруденения анорогенных гранитоидов шибеликского комплекса Горного Алтая, который представлен сильно фракционированными разностями. С ними пространственно и парагенетически связаны различные типы оруденения Zr, Nb, Ta и TR. Цель исследования: изучить петрологические, геохимические особенности пород, акцессорного циркона и оруденения Шибеликского ареала с использованием экспериментальных диаграмм, позволяющих выявлять генетические проблемы и физико-химические особенности магматогенного и гидротермального цирконов. Методы исследований включали изучение зональных и незональных кристаллов сфена и апатита с применением лазерно-абляционного анализа методом индуктивно-связанной плазмы на спектрометре «ОРTIMA-4300» с высокой чувствительностью определения элементов в Лаборатории Объединённого института геологии и геофизики Сибирского отделения РАН (г. Новосибирск). Определение элементов-примесей в цирконах выполнено методом LA-ICP-MS (масс-спектрометрия с индуктивно связанной плазмой и с лазерной абляцией) на масс-спектрометре ELEMENT 2 (фирма Thermo Finnigan Mat) с лазерной приставкой UP-2B, Nd: YAG (фирма New Wave Research) в ИГМ СО РАН (г. Новосибирск). Результаты. В статье приведены данные по геохимии и петрологии щелочных гранитоидов, магматического и гидротермального циркона шибеликского комплекса Горного Алтая. На основе представительных анализов пород и акцессорного циркона расшифровываются особенности генерации гранитоидов, их рудоносности и типизации. Гранитоиды отнесены к агпаитовым сильно фракционированным разностям. В них и в цирконе проявлен тетрадный эффект фракционирования (ТЭФ) РЗЭ М-типа, обусловленный высокой насыщенностью фтор-обогащёнными флюидами. Увеличение значений ТЭФ РЗЭ коррелируется с возрастанием кислотности среды. Выявляется экстремальная некогерентность отношений элементов к хондриту и несоответствие поведения заряд-радиусным характеристикам. Магматогенный циркон характеризуется призматической и пирамидальной формой кристаллов и высокими концентрациями Hf, Y, Sc и тяжёлых РЗЭ. Гидротермальный циркон имеет более высокие концентрации Nb, Ta и суммы TR.The relevance of the discussed issue is caused by the need of researching petrology, geochemistry and ore mineralization of anorogenic granitoids of Shibelikskii complex which is represented by strong fractionated rocks. Different types of ore mineralization of Zr, Nb, Ta and REE are related to such rocks spatially and paragenetically. The main aim of the research is to study petrology, geochemical features of rocks, accessory mineral zircon and ore mineralization of Shibelikskii areal using the experimental diagrams, which allow revealing the genetic problems and determining physic-chemical features of magamatic and hydrothermal zircon crystals. The methods used in the study. Rare and scattered elements were determined in rocks by inductively coupled plasma method on the mass spectrometer «ОРTIMA-4300», the rest elements, including REE, were determined by La-ISP-MS methods in the Laboratory OIGaG SO RAN (Novosibirsk). Chemical elements in zircon were determined by La-ISP-MS mass-spectrometry method with inductively coupled plasma and laser ablation on the mass-spectrometer ELEMENT 2 (Thermo Finnigan Mat) with laser device UP-2B, Nd: YAG (New Wave Research) in the Laboratory OIGaG SO RAN (Novosibirsk). Results. The paper introduces the data on geochemistry and petrology of alkali granitoids and accessory magmatic and hydrothermal zircon of Shibelikskii complex in Gorny Altai. Based on the representative analysis of rocks and zircon the features of granitoids generation, their ore mineralization and typification are determined. The granitoids refer to agpaitic strong fractionation rocks. The tetradic effect of REE M-type fractionation appears in the rocks and in zircon. It is caused by high saturation with fluoro-rich fluids. Increase in meanings of tetradic effect of REE is correlated with the growth of the environment acidity. The author has determined the extreme non-coherence of elements ratio to chondrite and non-conformity of behavior to charge-and-radius-controlled characteristics. Magmatic zircon is characterized by prismatic and pyramid crystal form and high contents of Hf, Y, Sc, and heavy REE. Hydrothermal zircon has higher contents of Nb, Ta and sum of REE

A Complexity Measure for Continuous Time Quantum Algorithms

We consider unitary dynamical evolutions on n qubits caused by time dependent pair-interaction Hamiltonians and show that the running time of a parallelized two-qubit gate network simulating the evolution is given by the time integral over the chromatic index of the interaction graph. This defines a complexity measure of continuous and discrete quantum algorithms which are in exact one-to-one correspondence. Furthermore we prove a lower bound on the growth of large-scale entanglement depending on the chromatic index.Comment: 6 pages, Revte

Existence of Multistring Solutions of the Self-Gravitating Massive W−W-Boson

We consider a semilinear elliptic system which include the model system of the $W-$strings in the cosmology as a special case. We prove existence of multi-string solutions and obtain precise asymptotic decay estimates near infinity for the solutions. As a special case of this result we solve an open problem posed in \cite{yan}Comment: 12 page

Numerical Bifurcation Analysis of Conformal Formulations of the Einstein Constraints

The Einstein constraint equations have been the subject of study for more than fifty years. The introduction of the conformal method in the 1970's as a parameterization of initial data for the Einstein equations led to increased interest in the development of a complete solution theory for the constraints, with the theory for constant mean curvature (CMC) spatial slices and closed manifolds completely developed by 1995. The first general non-CMC existence result was establish by Holst et al. in 2008, with extensions to rough data by Holst et al. in 2009, and to vacuum spacetimes by Maxwell in 2009. The non-CMC theory remains mostly open; moreover, recent work of Maxwell on specific symmetry models sheds light on fundamental non-uniqueness problems with the conformal method as a parameterization in non-CMC settings. In parallel with these mathematical developments, computational physicists have uncovered surprising behavior in numerical solutions to the extended conformal thin sandwich formulation of the Einstein constraints. In particular, numerical evidence suggests the existence of multiple solutions with a quadratic fold, and a recent analysis of a simplified model supports this conclusion. In this article, we examine this apparent bifurcation phenomena in a methodical way, using modern techniques in bifurcation theory and in numerical homotopy methods. We first review the evidence for the presence of bifurcation in the Hamiltonian constraint in the time-symmetric case. We give a brief introduction to the mathematical framework for analyzing bifurcation phenomena, and then develop the main ideas behind the construction of numerical homotopy, or path-following, methods in the analysis of bifurcation phenomena. We then apply the continuation software package AUTO to this problem, and verify the presence of the fold with homotopy-based numerical methods.Comment: 13 pages, 4 figures. Final revision for publication, added material on physical implication

Far-from-constant mean curvature solutions of Einstein's constraint equations with positive Yamabe metrics

In this article we develop some new existence results for the Einstein constraint equations using the Lichnerowicz-York conformal rescaling method. The mean extrinsic curvature is taken to be an arbitrary smooth function without restrictions on the size of its spatial derivatives, so that it can be arbitrarily far from constant. The rescaled background metric belongs to the positive Yamabe class, and the freely specifiable part of the data given by the traceless-transverse part of the rescaled extrinsic curvature and the matter fields are taken to be sufficiently small, with the matter energy density not identically zero. Using topological fixed-point arguments and global barrier constructions, we then establish existence of solutions to the constraints. Two recent advances in the analysis of the Einstein constraint equations make this result possible: A new type of topological fixed-point argument without smallness conditions on spatial derivatives of the mean extrinsic curvature, and a new construction of global super-solutions for the Hamiltonian constraint that is similarly free of such conditions on the mean extrinsic curvature. For clarity, we present our results only for strong solutions on closed manifolds. However, our results also hold for weak solutions and for other cases such as compact manifolds with boundary; these generalizations will appear elsewhere. The existence results presented here for the Einstein constraints are apparently the first such results that do not require smallness conditions on spatial derivatives of the mean extrinsic curvature.Comment: 4 pages, no figures, accepted for publication in Physical Review Letters. (Abstract shortenned and other minor changes reflecting v4 version of arXiv:0712.0798