Spin correlations in the electron-doped high-transition-temperature superconductor Nd{2-x}Ce{x}CuO{4+/-delta}

High-transition-temperature (high-Tc) superconductivity develops near antiferromagnetic phases, and it is possible that magnetic excitations contribute to the superconducting pairing mechanism. To assess the role of antiferromagnetism, it is essential to understand the doping and temperature dependence of the two-dimensional antiferromagnetic spin correlations. The phase diagram is asymmetric with respect to electron and hole doping, and for the comparatively less-studied electron-doped materials, the antiferromagnetic phase extends much further with doping [1, 2] and appears to overlap with the superconducting phase. The archetypical electron-doped compound Nd{2-x}Ce{x}CuO{4\pm\delta} (NCCO) shows bulk superconductivity above x \approx 0.13 [3, 4], while evidence for antiferromagnetic order has been found up to x \approx 0.17 [2, 5, 6]. Here we report inelastic magnetic neutron-scattering measurements that point to the distinct possibility that genuine long-range antiferromagnetism and superconductivity do not coexist. The data reveal a magnetic quantum critical point where superconductivity first appears, consistent with an exotic quantum phase transition between the two phases [7]. We also demonstrate that the pseudogap phenomenon in the electron-doped materials, which is associated with pronounced charge anomalies [8-11], arises from a build-up of spin correlations, in agreement with recent theoretical proposals [12, 13].Comment: 5 pages, 4 figure

Perturbation and disruption of plant hormone signaling by organic xenobiotic pollutions

International audiencePlant hormone signaling plays an important role in many physiological and developmental processes including stress response. With the advent of new post-genomic molecular techniques the potential for increasing our understanding of the impact of hormone signaling on gene expression and adaptive processes has never been higher. Unlocking the molecular underpinnings of these promises show great promise for the development of new plant biotechnologies and improved crop varieties. Plant Hormone Signaling Under Stress brings together the latest advances as well as the work being done to apply these findings more practically to plant and crop science. Plant Hormone Signaling Under Stress explores the role that signal pathways and transduction have in gene expression, plant adaptation, and stress response. Chapters look both broadly at stress environments and others explore the response to specific abiotic stressors. The book also contains several chapters that look to translate basic findings into sustainable and biotechnological advances

What Fosters Individual-Level Absorptive Capacity in MNCs? : An Extended Motivation-Ability-Opportunity Framework

Absorptive capacity has been marked as one of the most important capabilities of Multinational Corporations for effective management of knowledge. To address calls for research on micro-level origins of the concept, this paper focuses on the determinants of individual-level absorptive capacity. We examine the extent to which individuals' capability to recognize, assimilate and exploit new knowledge from the environment is shaped by different forms of work motivation (i.e., intrinsic and extrinsic), overall ability, exposure to diverse country contexts and personal characteristics. Drawing on and extending the Motivation-Ability-Opportunity framework, we develop and test a set of hypotheses. Using a unique dataset collected from 648 individuals in a multinational corporation, we show that individuals' intrinsic motivation and overall ability are the key antecedents of absorptive capacity. In contrast, extrinsic motivation does not emerge as a significant predictor. We find that past international assignments to distant countries could be detrimental to individuals' absorptive capacity. However, our results suggest that for those individuals who are open to new experiences, assignments to distant countries become useful opportunity for absorptive capacity development. These findings contribute to existing literature by showing effects of alternative types of motivation and underscoring the importance of using selective assignment when considering exposure to diverse country context as a tool for employee capability development