Hydrothermal synthesis and structure of [Ni(en)(2)V6O14](n)

A new complex [Ni (en)(2)V6O14](n) was hydrothermally synthesized and characterized by 2-dimensional vanadium oxide framework pillared by Ni(en)(2)group. Single crystal X-ray analysis indicates that this compound crystallizes in monoclinic system, space group P2(1)/c with a=0. 892 17(18) nm, b = 1. 711 1(3) nm, c=0. 662 73(13) nm, beta=111. 58(3)degrees, V=0.940 8(3) nm(3), Z=2, D-c=2.501 g/cm(3), R=0. 042 3, omegaR=0. 060 9, S=1. 006.

Crystal structure and drawing-induced polymorphism in poly(aryl ether ether ketone). IV

A new crystal modification induced by strain and denoted as form II exists alongside the dominant form I structure in the uniaxially oriented poly(ether ether ketone) (PEEK) and the related polymers. The crystal structure of form II for PEEK is also found to possess a two-chain orthorhombic packing with unit cell parameters of a equal to 0.475 nm, b equal to 1.060 nm, and c equal to 1.086 nm. More extended and flattened chain conformation of form II relative to that of form I is expected to account for an 8% increase in c-axis dimension, which is attributed to the extensional deformation fixed in situ through strain-induced crystallization during uniaxial drawing. Annealing experiments suggest that form II is thermodynamically metastable and can be transformed into more stable form I by chain relaxation and reorganization at elevated temperature without external tension. This strain-induced polymorphism exists universally in the poly(aryl ether ketone) family. (C) 1999 John Wiley & Sons, Inc.

草毡寒冻雏形土有机质补给、分解及大气CO2通量交换

调查草毡寒冻雏形土生物量及土壤有机质,利用涡度相关技术观测该区域作用层与大气CO2通量.结果表明：地下90%生物量集中于0～10 cm的表土层,年总净初级生产量约935.0 g/m2;土壤有机质含量在6.401～7.060%之间;净CO2通量呈明显的日变化和季节变化规律;5月中旬到9月底为CO2的净吸收（780 g CO2/m2）,其中以7月最高,净吸收量明显高于非生长季的,10月到翌年5月初CO2的净排放量（383 g CO2/m2）;全年固定碳高达397 g/m2.

湖泊生态系统铁同位素与硫同位素地球化学研究--以红枫湖、阿哈湖为例

湖泊生态系统是陆地水体生态系统的重要组成部分。随着社会经济的不断发展，各种人为因素对湖泊生态系统的影响日益突出，打破了其自然演变规律，诸如 “二次污染”、水体富营养化、重金属污染等环境问题接踵而来。而铁是水生生态系统初级生产力所必需的重要微量营养元素之一，在一定的条件下可以控制和影响浮游藻类的生长速度和种类；而且，铁的氧化还原敏感性很强，其价态的改变往往会影响其它相关重金属的迁移和转化。因此，湖泊生态系统中铁的生物地球化学循环研究具有非常重要的意义。近年来的研究显示，铁同位素分析技术可以用于各种生物作用和非生物作用过程的研究，在海洋和河流生态系统中已有广泛的应用，而对湖泊生态系统的研究则鲜见报导。乌江流域中等富营养化的湖泊――红枫湖和贵阳西南郊矿化程度较高的湖泊――阿哈湖是研究湖泊生态系统中铁生物地球化学循环的理想场所。本文选取这两个性质不同的湖泊为研究对象，运用硫同位素、铁同位素及重金属和营养盐等地球化学方法手段，对两湖流域内硫酸盐的来源、硫同位素的季节和剖面变化特征、铁的来源及铁同位素组成的季节和剖面变化特征及其控制和影响因素等进行了研究和探讨，进一步完善了铁同位素分馏机理，为深化理解和研究湖泊生态系统中铁和硫的生物地球化学循环提供一定的科学依据。论文所获的主要认识总结如下： 两湖流域内湖水与河水的硫酸盐硫同位素地球化学 （1）阿哈湖流域和红枫湖流域水体的硫酸盐浓度和δ34S值均有较宽的分布范围。各入湖支流中，受煤矿废水或煤矸石淋溶液污染的河水的δ34S值相对较低（-8.10‰～-14.92‰），而受生活污水影响严重的河水则具有相对较高的δ34S值（-5.68‰～+0.88‰）。相比而言，阿哈湖流域水体纳入了大量的煤矿废水和煤矸石淋溶液，硫污染程度较红枫湖流域更为严重。因此，阿哈湖湖水具有相对较高的硫酸根浓度（平均为2.30 mmol.L-1）和相对较低的δ34S值（平均为-8.10‰），而红枫湖则具有相对较低的硫酸根浓度（平均为0.96 mmol.L-1）和相对较高的δ34S值（平均为-6.80‰）。 （2）阿哈湖湖水中的硫酸盐主要受煤矿废水、煤矸石淋溶液以及雨水等的控制；红枫湖湖水的硫酸盐主要来源于煤中黄铁矿的氧化和雨水输入，土壤硫化物的氧化和蒸发岩的溶解对湖水硫酸盐硫同位素组成的贡献较小。相比之下，雨水对红枫湖湖水硫同位素的影响更为明显。 （3）红枫湖和阿哈湖湖水的硫酸盐的δ34S值均具有明显的剖面变化特征，而且两湖的变化趋势相似，总体表现为，夏秋季节表层湖水和底层湖水的δ34S值相对较高，而冬春季节湖水剖面上下几乎没有变化。湖水硫酸盐浓度也呈现类似的变化特征，这主要与季节性厌氧湖泊夏季分层冬季混和的典型特点有关。夏季湖水分层期间，大量降雨在湖泊表层的滞留使得δ34S值升高而硫酸盐浓度降低，湖泊底部水层中硫酸盐细菌的还原作用使得底层湖水的硫酸盐浓度降低，而δ34S值升高。 两湖流域内铁同位素地球化学 （1）阿哈湖流域各类样品的δ56Fe值分布在-2.03‰～+0.12‰之间，分布范围较宽。其中湖水悬浮颗粒物的δ56Fe值在-1.36‰～-0.03‰之间，整体相对偏负。湖周各支流河水悬浮颗粒物的δ56Fe值在-0.88‰～+0.07‰之间，也相对富集轻的铁同位素；湖底沉积物和孔隙水的δ56Fe值的分布范围分别为-1.75‰～-0.59‰和-2.03‰～+0.12‰；大气颗粒物和浮游藻类的δ56Fe值分别为+0.06±0.02‰和+0.08‰。与阿哈湖相比，红枫湖流域各类样品的δ56Fe值的分布范围相对较窄，在-0.92‰～+0.36‰之间。湖水悬浮颗粒物的δ56Fe值在-0.85‰～+0.14‰之间，河水悬浮颗粒物的铁同位素组成变化范围为-0.89‰～+0.10‰，二者的变化范围相似。红枫湖沉积物的δ56Fe值在-0.18‰～+0.08‰之间，明显比阿哈湖沉积物的铁同位素组成偏正；而对应孔隙水的铁同位素组成的变化范围为-0.59‰～-0.24‰，均要比对应沉积物的铁同位素值要低。藻类和鲫鱼鱼肉的δ56Fe值分别为+0.36‰和-0.92‰。 （2）通过对两湖研究区湖水悬浮颗粒物与各输入端员环境样品的铁同位素值的研究表明，湖水悬浮颗粒物的δ56Fe值不仅受各输入端员的控制和影响，湖泊内部相关的生物地球化学过程也对湖水悬浮颗粒物的铁同位素组成变化产生了重要影响。两湖研究区内湖水悬浮颗粒物的铁同位素组成均存在季节变化特征，但受湖泊自身特点的影响，主要控制因素方面存在一定差异。夏季阿哈湖湖水悬浮颗粒物的铁同位素值变幅较大，其变化主要表现在表层和底层。表层因受陆源输入的有机结合态铁的影响而具有较负的δ56Fe值，而大气沉降颗粒物和湖泊表层的浮游藻类的影响并不显著。夏季湖水分层期间，“Ferrous Wheel”铁循环对于界面附近铁同位素的重分配起到了主要的控制和影响作用，湖水悬浮颗粒物的铁同位素值在氧化－还原界面附近达到了极负值。水－沉积物界面附近滞水层中亚铁类硫化物的生成可能也是水－沉积物界面附近水层内颗粒物的δ56Fe值偏负的原因之一。而冬季湖水混和时期，阿哈湖湖水剖面悬浮颗粒物的δ56Fe值的变幅明显减小。与阿哈湖不同，藻类的吸附作用可能在夏季红枫湖上层水体中占有主导地位，其湖水悬浮颗粒物的铁同位素组成随叶绿素水平的降低而逐渐降低。下层湖水悬浮颗粒物的铁同位素组成变化也受“Ferrous Wheel”铁循环的影响，在红枫湖后五剖面 20m 处达到-0.18‰，大坝剖面底层约为-0.46‰，其变幅没有阿哈湖悬浮颗粒物的δ56Fe值大，可能是受到了湖水中大量有机物质的影响。冬季红枫湖后五剖面的变化趋势与夏季相似，上层和下层水体悬浮颗粒物分别受不同影响因素的控制。上层水体悬浮颗粒物的铁同位素变化不明显，与Fe、Al、Mn、Zn、Co等元素的含量呈现良好的正相关关系；而底层水体悬浮颗粒物的δ56Fe值变幅比夏季要大，HW采样点20m处可达-0.85‰，与Fe、Al、Zn、Co等呈现良好的负相关关系，具体影响因素还有待于进一步研究。

The dynamics of a topological change in a system of soap films

Hutzler, S., Saadatfar, M., van der Net, A., Weaire, D. and Cox, S.J. (2007) The dynamics of a topological change in a system of soap films. Coll. Surf. A, 323:123-131. Sponsorship: This research was supported by the European Space Agency (contracts 14914/02/NL/SH and 14308/00/NL/SH), Science Foundation Ireland. (RFP 05/REP/PHY00/6), and the EU program COST P21 (The Physics of droplets). SJC acknowledges support from EPSRC (EP/D071127/1). MS is supported by the Irish Higher Education Authority (PRTLI-IITAC).

Asesoría de diseño en producción de los productos para la cadena productiva del mopa mopa.

52 hojas : ilustraciones, fotografías a color.

Fuzzy ART Choice Functions

Adaptive Resonance Theory (ART) models are real-time neural networks for category learning, pattern recognition, and prediction. Unsupervised fuzzy ART and supervised fuzzy ARTMAP networks synthesize fuzzy logic and ART by exploiting the formal similarity between tile computations of fuzzy subsethood and the dynamics of ART category choice, search, and learning. Fuzzy ART self-organizes stable recognition categories in response to arbitrary sequences of analog or binary input patterns. It generalizes the binary ART 1 model, replacing the set-theoretic intersection (∩) with the fuzzy intersection(∧), or component-wise minimum. A normalization procedure called complement coding leads to a symmetric theory in which the fuzzy intersection and the fuzzy union (∨), or component-wise maximum, play complementary roles. A geometric interpretation of fuzzy ART represents each category as a box that increases in size as weights decrease. This paper analyzes fuzzy ART models that employ various choice functions for category selection. One such function minimizes total weight change during learning. Benchmark simulations compare peformance of fuzzy ARTMAP systems that use different choice functions.

A note on spin-s duality

Duality is investigated for higher spin (s ≥ 2), free, massless, bosonic gauge fields. We show how the dual formulations can be derived from a common "parent", first-order action. This goes beyond most of the previous treatments where higher-spin duality was investigated at the level of the equations of motion only. In D = 4 spacetime dimensions, the dual theories turn out to be described by the same Pauli-Fierz (s = 2) or Fronsdal (s ≥ 3) action (as it is the case for spin 1). In the particular s = 2 D = 5 case, the Pauli-Fierz action and the Curtright action are shown to be related through duality. A crucial ingredient of the analysis is given by the first-order, gauge-like, reformulation of higher spin theories due to Vasiliev. © SISSA/ISAS 2003.

Chromatin: bind at your own RSC.

Recent work has identified a novel RSC-nucleosome complex that both strongly phases flanking nucleosomes and presents regulatory sites for ready access. These results challenge several widely held views.

Private equity and employment - the Davos/WEF/Harvard study

The World Economic Forum at Davos has published a major study showing that workplaces of firms taken over by private equity have 10% less employees 5 years after the takeover, than other similar workplaces. The rate of plant closures, opening, acquisitions and disposals is twice as high as in other firms, and the net effect is still a job loss of 3.6%-4.5% after only 2 years, compared with other firms. Firms taken over by private equity are also more likely to go bankrupt than publicly quoted firms.

El hombre metrosexual como Narciso contemporáneo: el papel del discurso publicitario actual en la construcción de la masculinidad

Existen diferentes definiciones del concepto de masculinidad. Por un lado están las normativas, que la entienden como lo que los hombres deberían ser y, por otro, los enfoques semióticos, que la definen como no-feminidad. Partiendo de este último enfoque y teniendo en cuenta que la feminidad ha evolucionado en los últimos años junto con la sociedad desdibujando la frontera entre lo que forma parte del rol femenino y lo que no, se puede afirmar que han surgido a partir de los renovados modelos de feminidad, diferentes y nuevas masculinidades entre las que se encuentra la del hombre metrosexual. Es en este tipo de masculinidad en concreto en la que se centra la presente investigación y en cómo se construye la narración de dicha masculinidad en el discurso publicitario actual recurriendo a la figura mítica de Narciso. Así, a partir de una revisión bibliográfica y de un análisis de contenido, se pretende analizar la influencia de la publicidad en la aparición del hombre metrosexual como nueva masculinidad en respuesta a la transformación de la feminidad, a la par que confirmar la presencia de la figura de Narciso como recurso en la construcción de la masculinidad en la publicidad actual.

Effect of a COL1A1 Sp1 Binding Site Polymorphism on Arterial Pulse Wave Velocity: An Index of Compliance.

Reduced arterial compliance precedes changes in blood pressure, which may be mediated through alterations in vessel wall matrix composition. We investigated the effect of the collagen type I-1 gene (COL1A1) +2046G>T polymorphism on arterial compliance in healthy individuals. We recruited 489 subjects (251 men and 238 women; mean age, 22.6±1.6 years). COL1A1 genotypes were determined using polymerase chain reaction and digestion by restriction enzyme Bal1. Arterial pulse wave velocities were measured in 3 segments, aortoiliac (PWVA), aortoradial (PWVB), and aorto-dorsalis-pedis (PWVF), as an index of compliance using a noninvasive optical method. Data were available for 455 subjects. The sample was in Hardy-Weinberg equilibrium with genotype distributions and allele frequencies that were not significantly different from those reported previously. The T allele frequency was 0.22 (95% confidence interval, 0.19 to 0.24). Two hundred eighty-three (62.2%) subjects were genotype GG, 148 (35.5%) subjects were genotype GT, and 24 (5.3%) subjects were genotype TT. A comparison of GG homozygotes with GT and TT individuals demonstrated a statistically significant association with arterial compliance: PWVF 4.92±0.03 versus 5.06±0.05 m/s (ANOVA, P=0.009), PWVB 4.20±0.03 versus 4.32±0.04 m/s (ANOVA, P=0.036), and PWVA 3.07±0.03 versus 3.15±0.03 m/s (ANOVA, P=0.045). The effects of genotype were independent of age, gender, smoking, mean arterial pressure, body mass index, family history of hypertension, and activity scores. We report an association between the COL1A1 gene polymorphism and arterial compliance. Alterations in arterial collagen type 1A deposition may play a role in the regulation of arterial compliance

Optical observations of 23 distant Jupiter Family Comets, including 36P/Whipple at multiple phase angles

We present photometry on 23 Jupiter Family Comets (JFCs) observed at large heliocentric distance, primarily using the 2.5-m Isaac Newton Telescope (INT). Snapshot images were taken of 17 comets, of which five were not detected, three were active and nine were unresolved and apparently inactive. These include 103P/Hartley 2, the target of the NASA Deep Impact extended mission, EPOXI. For six comets we obtained time-series photometry and use this to constrain the shape and rotation period of these nuclei. The data are not of sufficient quantity or quality to measure precise rotation periods, but the time-series do allow us to measure accurate effective radii and surface colours. Of the comets observed over an extended period, 40P/Väisälä 1, 47P/Ashbrook-Jackson and P/2004 H2 (Larsen) showed faint activity which limited the study of the nucleus. Light curves for 94P/Russell 4 and 121P/Shoemaker-Holt 2 reveal rotation periods of around 33 and 10h, respectively, although in both cases these are not unique solutions. 94P was observed to have a large range in magnitudes implying that it is one of the most elongated nuclei known, with an axial ratio a/b >= 3. 36P/Whipple was observed at five different epochs, with the INT and ESO's 3.6-m NTT, primarily in an attempt to confirm the preliminary short rotation period apparent in the first data set. The combined data set shows that the rotation period is actually longer than 24h. A measurement of the phase function of 36P's nucleus gives a relatively steep ß = 0.060 +/- 0.019. Finally, we discuss the distribution of surface colours observed in JFC nuclei, and show that it is possible to trace the evolution of colours from the Kuiper Belt Object (KBO) population to the JFC population by applying a `dereddening' function to the KBO colour distribution.

Electron-impact excitation of Cr II A theoretical calculation of collision and effective collision strengths for forbidden transitions

Context. Absorption or emission lines of Cr II are observed in a wide variety of astrophysical spectra and accurate atomic data are urgently needed to interpret these lines. Many of these data are impossible to measure experimentally and a full theoretical treatment is the only means by which these data can be obtained.

Aims. In this paper, we present collision strengths and effective collision strengths for electron-impact excitation of Cr II for forbidden transitions among the lowest-lying 74 fine-structure levels. Effective collision strengths have been computed for 18 individual electron temperatures of astrophysical importance, ranging from 2000-100 000 K.

Methods. The parallel suite of R-matrix packages, RMATRX II, which has recently been extended to allow for the inclusion of relativistic effects, has been used in the present work to compute the collision strengths and effective collision strengths for electron-impact excitation of Cr II. We concentrate in this publication on low-lying forbidden lines among the lowest 74 jj fine-structure levels with configurations 3d(5) and 3d(4)4s, although atomic data has been evaluated for all 39 060 transitions among the 280 jj levels of configurations 3d(5), 3d(4)4s and 3d(4)4p. This work constitutes the largest evaluation ever performed for this ion involving 1932 coupled channels.

Results. Collision and effective collision strengths are presented for all transitions among the lowest 74 J pi states of Cr II and comparisons made with the work of Bautista et al. (2009). While the effective collision strengths agree well for some transitions, significant discrepancies exist for others. We believe that the present atomic data represents the most accurate, most sophisticated and most complete data set for electron-impact excitation of Cr II and we would recommend them to astrophysicists and plasma physicists in their application work. We would expect that the effective collision strengths presented for the important low-lying forbidden lines are accurate to within 15%.