Breaking time-inversion invariance through decoherence : energetic consequences for attosecond neutron scattering

Nuclei and electrons in condensed matter and/or molecules are usually entangled, due to the prevailing (mainly electromagnetic) interactions. However, the "environment" of a microscopic scattering system (e.g. a proton) causes ultrafast decoherence, thus making atomic and/or nuclear entanglement e®ects not directly accessible to experiments. However, our neutron Compton scattering experiments from protons (H-atoms) in condensed systems and molecules have a characteristic collisional time about 100|1000 attoseconds. The quantum dynamics of an atom in this ultrashort, but ¯nite, time window is governed by non-unitary time evolution due to the aforementioned decoherence. Unexpectedly, recent theoretical investigations have shown that decoherence can also have the following energetic consequences. Disentangling two subsystems A and B of a quantum system AB is tantamount to erasure of quantum phase relations between A and B. This erasure is widely believed to be an innocuous process, which e.g. does not a®ect the energies of A and B. However, two independent groups proved recently that disentangling two systems, within a su±ciently short time interval, causes increase of their energies. This is also derivable by the simplest Lindblad-type master equation of one particle being subject to pure decoherence. Our neutron-proton scattering experiments with H2 molecules provide for the first time experimental evidence of this e®ect. Our results reveal that the neutron-proton collision, leading to the cleavage of the H-H bond in the attosecond timescale, is accompanied by larger energy transfer (by about 2|3%) than conventional theory predicts. Preliminary results from current investigations show qualitatively the same e®ect in the neutron-deuteron Compton scattering from D2 molecules. We interpret the experimental findings by treating the neutron-proton (or neutron-deuteron) collisional system as an entangled open quantum system being subject to fast decoherence caused by its "environment" (i.e., two electrons plus second nucleus of H2 or D2). The presented results seem to be of generic nature, and may have considerable consequences for various processes in condensed matter and molecules, e.g. in elementary chemical reactions.

有机化合物结构自动解析专家系统研究

本文建立了一个能用于含N、P、O、S、Si及卤素等多种杂原子的有机化合物结构自动解析专家系统ESESOC(Expert System for the Elucidation of the Structure of Orsanic Compounds)。它可从未知化合物的分子式、光谱数据(包括IR, MS，~1HNMK ~(13)CNMR, 2D-NMR等)及其它化学信息自动地推衍出与己知信息相一致的候选化合物结构。ESESOC系统由三个部分组成：(1)光谱知识库及其光谱解释模块；(2)结构产生器；(3)结构验证模块。其结构解析基本过程为：从分子式、光谱数据或其它化学信息出发，由未知化合物的光谱数据去检索光谱知识库，即进行数据分析并推断出该未知化合物中可能含有的结构碎片，然后由结构产生器从这些结构碎片进行候选化合物结构的穷举生成，最后对候选结构进行验证并输出结果。从而实现由化合物光谱数据鉴别未知化合物结构的自动化。结构产生器是系统的核心模块。对一个结构产生器的基本要求是：穷举性，非冗余性，有效性。要完成一个能实际使用的结构产生器，效率则是至关重要的。ESESOC系统生成结果的穷举和非冗余性己通过与图论计算结果及著名的DENDRAL系统的生成结果相比较得以证明。如由本系统生成的烷烃系列C_nH_(2n+2)，及醇、醚系列C_nH_(2n+2)0的异构体数目与图论理论计算的数目相同；对C_5H_n n = 12，10，8，6，4，2，O；C_6H_n n = 14，12，lO，8，6，4，2，O系列，及含多种杂原子(O、N、S等)的复杂体系，其异构体生成结果则与DENDRAL系统的生成结果完全一致(DENDRAL系统的结构生成算法是经数学证明了是正确的，其结果已被很多系统引为穷举和非冗余性的例证)。关于ESESOC系统的有效性，在同一计算机上测试结果表明ESESOC系统的结构生成效率比著名的日本的CHEMICS系统高很多倍。结构解析专家系统另一重要组成部分为谱图知识库，它是逻辑推理的基础。专家系统的效能取决于其子结构一子光谱相关的知识库的有效性，所以要建造一个有效的~(13)CNMR知识库，关键在于建立一个好的子结构模型．在~(13)CNMR知识库中，子结构的概念与常规的子结构概念有所不同，它包括两个组成部分，(1)中心原子，它对应于一个化学位移；(2)环境部分，结构环境决定了中心原子的化学位移峰的位置。子结构模型的选择要适当兼顾信息全面和防止“组合爆炸”两个因素。ESESOC系统从~(13)CNMR本身的特征出发，提出了不确定层数的子结构模型。即以共振碳原子为中心，以与之相连的完整的官能团为外围环境，对这样的子结构，其外围环境根据官能团的不同可以是一层、或二层乃至多层，即环境层数是可变的。此即为ESESOC系统的广义-层子结构模型，它具有包含结构信息全，所有可能存在的子结构数量适中等优点。在此子结构模型的基础上，从CIAC-~(13)CNMR谱图数据库统计出。~(13)CNMR知识库，即子结构-~(13)CNMR化学位移相关表。ESESOC系统中结构验证方法有： ~(13)CNMR谱峰数预测，~(13)CNMR波谱模拟，应力能计算等。在结构解析专家系统研究中还涉及到如下三个问题：(1)结构编码；(2)结构之间相互比较；(3)结构中原子的对称性分析。在本研究中，对这些问题都提出了新的方案，并均获得较好结果。(1)在建造化合物结构信息系统时，首先要解决化合物结构的计算描述，即结构编码问题，以进行化合物结构的计算机存储和管理。为此我们提出了两种新的拓扑指数编码方案，即ID指数和EAID指数。由ESESOC结构产生器穷生成了含1-22个碳原子的380多万个链烷烃异构体，含1-12四价碳原子的20多万仑复杂多环异构体及40多万个含杂原子的化合物，通过对这3个系列共440多万个化合物结构的验证，结果表明，ID和EAID指数对这440多万个化合物结构均能唯一地区分，即没有出现简并(简并是指两个或多个不同的结构具有相同的拓扑指数值)。这是迄今未见报道的。(2)在计算机结构信息处理中，最常遇到的一个问题就是确认一个结构是新结构还是为已知结构，这就要把该结构与库中的结构进行逐个比较。为了结构的比较，我们以二维连接表描述化合物的结构，因连接表随化合中原子的编序的变化而变化，因而就需要有一套序号赋值规则，无论结构图在画法或形状以及原子的序号上如何变化，都可使得结构图中的各原子按该规则得到唯一的排序方案。ESESOC系统的唯一性序号方案集中了Morgan算法及其改进方案之所长，并加入新的图的不变量，如最小环指数等以正确地划分分子中的原子，从而得到一个新的唯一性排序方案，该方案效率较高，可适用于各类复杂化合物。在ESESOC系统中，我们还以一维的整数数组来存贮和管理二维连接表，即得到压缩连接表，这在结构比较时大大地节省了系统开销，提高了比较速度。在同一结构中，若各原子由两种不同编序方案得到同一连接矩阵，则与某一序号所对应的两个原子所在结构图中的拓扑环境是等价的，也就是说两个节点是拓扑等价的，或具有拓扑对称性(Topological Symmetry)。化合物结构中原子的唯一性排序算法，有机化物结构异构体穷举生成过程中冗余对接的消除，NMR谱模拟等都与拓扑对称性密切相关。在ESESOC系统建造过程中，我们提出了三个新的拓扑等价性分析算法，它们是基于节点矩阵的拓扑等价性算法，基于全通道算法的拓扑等价性算法，以及基于扩展连接矩阵算法的拓扑等价性算法。这些算法结果准确，效率高，适用于各类化合物。

ELECTROCHEMICAL STUDY OF ISOPOLY AND HETEROPOLY ANION TRANSFER ACROSS THE WATER NITROBENZENE INTERFACE .2. VANADIUM-CONTAINING HETEROPOLYTUNGSTATE ANIONS

The electrochemical transfer behaviour of vanadium-containing heteropolytungstate anions [PW12-xVxO40]((3+r)-) (x = 1-4) across the water \nitrobenzene interface has been investigated by cyclic voltammetry and chronopotentiometry with cyclic linear current scanning. The transfer of PW11V1O404-, HPW10V2O404-, H2PW10V2O403-, H3PW9V3O403- and H4PW8V4O(40)(3-) across the water \nitrobenzene interface can be observed within the potential window. The effects were observed of pH in the water phase on the transfer behaviour and the formation of vanadium-containing heteropolytungstate anions in solution. Heteropolytungstate anions become more stable due to their involving the vanadium atom. The degree of protonation and the dissociation constant of the trivalent vanadium-containing heteropolytungstate anion of protonation increase with increasing vanadium content. The transfer processes are diffusion-controlled The standard transfer potential, the standard Gibbs energy and the dissociation constant for vanadium-containing heteropolytungstate anions have been obtained and the transfer mechanisms are discussed.

COMP3016 Web Technology - Strand 3 "History" Lecture 6

Lecture 6: Where are all the links taking us: Web Science Contains Powerpoint Lecture slides and Hypertext Research Papers: The Literati (The Cyberspace and critical theory website) (Eastgate website); Pervasive Hypertext at Southampton and at Aarhus; Adaptive Hypertext - The Next Big Thing: (De Bra & Chepegin, 2004); Web Science: Creating a Science of the Web (Berners-Lee, Hall, Hendler, Shadbolt & Weitzner, 2006).

Plan de ventas para el cumplimiento de metas y presupuestos de SUMARC TAT

La empresa SUMARC TATS.A.S se ha desempeñado desde su fundación como distribuidor de los productos de NUTRESA en el canal tradicional y durante los últimos ocho años se ha mantenido en el mercado enfrentando retos y desafíos que le permiten hoy en día tener un amplio conocimiento del canal. Sin embargo, en los últimos meses se han detectado falencias en términos de cumplimiento de metas y presupuestos, lo cual implica que la empresa debe diseñar un nuevo esquema comercial que le permita cumplir con sus metas y presupuestos teniendo en cuenta los requerimientos de su socio comercial, NUTRESA. El presente proyecto de aplicación práctica pretende entonces contribuir al mejoramiento de las estrategias comerciales y el esquema organizacional de la empresa para lograr el cumplimiento al 100% de las metas y presupuestos y así garantizar la rentabilidad y el desarrollo eficiente de todas las actividades de la empresa. Para lograr estos objetivos se trabajó en conjunto con la gerencia y el departamento comercial de la empresa, realizando un diagnóstico completo de la situación inicial a través de herramientas cuantitativas y cualitativas, para así focalizar los esfuerzos hacia la solución de las causas raíces del problema. Una vez identificadas las falencias se diseñó un plan de acción para sacar provecho de las fortalezas y oportunidades existentes y hacer frente a las debilidades y amenazas presentes, con el fin de lograr un impacto positivo en todas las áreas funcionales de la empresa, los indicadores de cumplimiento y rentabilidad del negocio y la perdurabilidad del mismo.

Integrated net primary production during POLARSTERN cruise ARK-XXVII/3 (IceArc) in 2012

Depth-integrated in situ rates were calculated for each environment as a function of the available photosynthetically active radiation (PAR). Irradiance profiles were calculated for each environment (sea ice, melt pond, water under the ice and open water) from the daily average incoming solar shortwave irradiance measured by a pyranometer (Kipp & Zonen, Delft, Netherland) mounted on the ship. We used light attenuation coefficients of 10 m**-1 for snow, 1.5 m**-1 for sea ice (Perovich, 1996) and 0.1 m**-1 for Atlantic-influenced Arctic seawater, based on literature values and observations during the cruise. Planar irradiance was transformed to scalar irradiance according to Ehn and Mundy (2013) and Katlein et al., (2014). Water column production was integrated over the euphotic zone (1% of incoming irradiance) and sea ice production over the ice core thickness. Melt pond coverage and sea ice concentration were taken into account when calculating the total primary production per area.

Carbon uptake rate calculated for CTD water samples during POLARSTERN cruise ARK-XXVII/3 (IceArc) in 2012

Net Primary Production was measured using the 14**C uptake method with minor modifications. Seawater samples were spiked with 0.1µCi ml**-1 of 14**C labelled sodium bicarbonate (Moravek Biochemicals, Brea, USA) and distributed in 10 clear bottles (20 ml each). Subsequently they were incubated for 12 h at -1.3°C under different scalar irradiances (0-420 µmol photons m**-2 s**-1) measured with a spherical sensor (Spherical Micro Quantum Sensor US-SQS/L, Heinz Walz, Effeltrich, Germany). At the end of the incubation, samples were filtered onto 0.2 µm nitrocellulose filters and the particulate radioactive carbon uptake was determined by liquid scintillation counting using Filter count scintillation cocktail (Perkin Elmer, Waltham, USA). The carbon uptake values in the dark were subtracted from the carbon uptake values measured in the light incubations. Dissolved inorganic carbon (DIC) was measured for each sample using the flow injection system (Hall and Aller, 1992). The DIC concentration was taken into account to calculate the amount of labeled bicarbonate incorporated into the cell. Carbon fixation rates were normalized volumetrically and by chlorophyll a. Photosynthesis-irradiance curves (PI curves) were fitted using MATLAB® according to the equation proposed by Platt et al. (1980) including a photoinhibition parameter (beta) and providing the main photosynthetic parameters: maximum Chla normalized carbon fixation rate if there were no photoinhibition (Pb) and the initial slope of the saturation curve (alpha). The derived parameters: light intensity at which photosynthesis is maximal (Im), the carbon fixation rate at that maximal irradiance (Pbm) and the adaptation parameter or photoacclimation index (Ik) were calculated according to Platt et al. (1982).