欧洲和中国的创意城市

在过去十几年里,没有一个概念能够像“创意城市”那样对欧洲的学术论著、城市政策和战略思考等产生如此强烈的影响.很多人认为创意城市理念已经成长为城市发展的一种新范式;但在另一部分人眼里,它不过是一种不可持续的、创造性的概念热潮而已,一旦人们发现创意城市实际能带来的现实效应非常有限,它的政治吸引力就会逐渐消失.事实上,尽管创意城市的概念非常模糊和笼统,但在全球化和城市竞争日益加剧的特殊时代背景下,它仍然激励着无数规划师、政策决策者和城市开发管理人员,想方设法地通过“创意”来推进文化、经济和城市的全面发展:     

Advanced solid-state NMR characterization of marine dissolved organic matter isolated using the coupled reverse osmosis/electrodialysis method

Advanced (13)C solid-state techniques were employed to investigate the major structural characteristics of two surface-seawater dissolved organic matter (DOM) samples isolated using the novel coupled reverse osmosis/electrodialysis method. The NMR techniques included quantitative (13)C direct polarization/magic angle spinning (DP/MAS) and DP/MAS with recoupled dipolar dephasing, (13)C cross-polarization/total sideband suppression (CP/TOSS), (13)C chemical shift anisotropy filter, CH, CH(2), and CH(n) selection, two-dimensional (1)H-(13)C heteronuclear correlation NMR (2D HETCOR), 2D HETCOR combined with dipolar dephasing, and (15)N cross-polarization/magic angle spinning (CP/MAS). The two samples (Coastal and Marine DOM) were collected at the mouth of the Ogeechee River and in the Gulf Stream, respectively. The NMR results indicated that they were structurally distinct. Coastal DOM contained significantly more aromatic and carbonyl carbons whereas Marine DOM was markedly enriched in alkoxy carbon (e.g., carbohydrate-like moieties). Both samples contained significant amide N, but Coastal DOM had nitrogen bonded to aromatic carbons. Our dipolar-dephased spectra indicated that a large fraction of alkoxy carbons were not protonated. For Coastal DOM, our NMR results were consistent with the presence of the major structural units of (1) carbohydrate-like moieties, (2) lignin residues, (3) peptides or amino sugars, and (4) COO-bonded alkyls. For Marine DOM, they were (1) carbohydrate-like moieties, (2) peptides or amino sugars, and (3) COO-bonded alkyls. In addition, both samples contained significant amounts of nonpolar alkyl groups. The potential sources of the major structural units of DOM were discussed in detail. Nonprotonated O-alkyl carbon content was proposed as a possible index of humification.     

A method for identifying water foraging bees by refractometer analysis: a spotlight on daily and seasonal water collecting activities of Apis mellifera L.

The current discussion about the relevance of guttation as a water source for honey bees (Apis mellifera L.) draws attention to the activity of water foraging bees. However, due to the wide foraging range, field observations of water foraging bees are difficult to carry out. Therefore, samples of returning bees were collected in front of the entrance early in the morning as well as during the day in summer and autumn 2010. In the laboratory, honey sacs of bees without pollen or propolis were examined. Honey sac samples with a weight of ≥0.005?g were classified as successful foragers. For the determination of water or nectar foragers, the honey sac contents of successful foragers were analyzed with a refractometer. Due to the dilution and the precision of the refractometer, an accuracy of 5?% was possible. Based on the known range of sugar concentrations in nectars, the analyzed samples were divided into nectar foragers (25–65?% sugar) and water foragers (0–15?% sugar). The study reveals that nectar and water foraging bees can be discriminated by analyzing the honey sac extracts with a refractometer. In autumn, the water demand of honey bee colonies is almost exclusively covered by water collection, whereas during summer nectar is mainly used as a substitute for water. In general, water collection is not restricted to certain times of the day.     

Lone‐Pair‐Induced Covalency as the Cause of Temperature‐ and Field‐Induced Instabilities in Bismuth Sodium Titanate

Bismuth sodium titanate (BNT)‐derived materials have seen a flurry of research interest in recent years because of the existence of extended strain under applied electric fields, surpassing that of lead zirconate titanate (PZT), the most commonly used piezoelectric. The underlying physical and chemical mechanisms responsible for such extraordinary strain levels in BNT are still poorly understood, as is the nature of the successive phase transitions. A comprehensive explanation is proposed here, combining the short‐range chemical and structural sensitivity of in situ Raman spectroscopy (under an applied electric field and temperature) with macroscopic electrical measurements. The results presented clarify the causes for the extended strain, as well as the peculiar temperature‐dependent properties encountered in this system. The underlying cause is determined to be mediated by the complex‐like bonding of the octahedra at the center of the perovskite: a loss of hybridization of the 6s² bismuth lone pair interacting with the oxygen p‐orbitals occurs, which triggers both the field‐induced phase transition and the loss of macroscopic ferroelectric order at the depolarization temperature.     

Important drug-micronutrient interactions: A selection for clinical practice

Abstract

Interactions between drugs and micronutrients have received only little or no attention in the medical and pharmaceutical world in the past. Since more and more pharmaceutics are used for the treatment of patients, this topic is increasingly relevant. As such interactions – depending on the duration of treatment and the status of micronutrients – impact the health of the patient and the action of the drugs, physicians and pharmacists should pay more attention to such interactions in the future. This review aims to sensitize physicians and pharmacists on drug micronutrient interactions with selected examples of widely pescribed drugs that can precipitate micronutrient deficiencies. In this context, the pharmacist, as a drug expert, assumes a particular role. Like no other professional in the health care sector, he is particularly predestined and called up to respond to this task. The following article intends to point out the relevance of mutual interactions between micronutrients and various examples of widely used drugs, without claiming to be exhaustive.     

I like it because I said that I like it: Evaluative conditioning effects can be based on stimulus-response learning.

Evaluative conditioning (EC) effects are often assumed to be based on a learned mental link between the CS (conditioned stimulus) and the US (unconditioned stimulus). We demonstrate that this link is not the only one that can underlie EC effects, but that if evaluative responses are actually given during the learning phase also a direct link between the CS and an evaluative response—a CS-ER link—can be learned and lead to EC effects. In Experiment 1, CSs were paired with USs and participants were asked to evaluate the pairs during the conditioning phase. Resulting EC effects were unaffected by a later revaluation of the USs, suggesting that these EC effects can be attributed to CS-ER learning rather than to CS-US learning. Experiment 2 replicated Experiment 1 with the difference that no evaluative responses were given during the learning phase. EC effects in this study were influenced by US revaluation, suggesting that these EC effects are mainly based on CS-US learning. In Experiment 3, it was shown that EC effects can be found even if the USs are entirely removed from the procedure and the CSs are only paired with enforced evaluative responses. Together the experiments show that the valence of a stimulus can change because of a contingency with an evaluative response. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Nanobiotechnology: A new look for nanopore sensing

Coating solid-state nanopores with fluid lipid bilayers can reduce the translocation speeds of molecules and prevent the nanopores from clogging.     

Mechanical properties of non-cohesive polygonal particle aggregates

We numerically investigate the effective material properties of aggregates consisting of soft convex polygonal particles, using the discrete element method. First, we construct two types of “sand piles” by two different procedures. Then we measure the averaged stress and strain, the latter via imposing a 10% reduction of gravity, as well as the fabric tensor. Furthermore, we compare the vertical normal strain tensor between sand piles qualitatively and show how the construction history of the piles affects their strain distribution as well as the stress distribution. In the next step, elastic constants are determined, assuming Hooke’s law to be locally valid throughout the sand piles. We determine the relationship between invariants of the stress and strain tensor, observing that the behaviour is nonlinear. While linear elastic behaviour near the centre of the pile is compatible with our data, nonlinearity signals the transition to plastic behaviour near its surface. A similar behaviour was assumed by Cantelaube et al. (Static multiplicity of stress states in granular heaps. Proc R Soc Lond A 456:2569–2588, 2000). We find that the macroscopic stress and fabric tensors are not collinear in the sand pile and that the elastic behaviour is anisotropic in an essential way.