Role of quantum nuclei and local fields in the x-ray absorption spectra of water and ice

We calculate the x-ray absorption spectra of liquid water at ambient conditions and of hexagonal ice close to melting, using a static GW approach that includes approximately local field effects. Quantum dynamics of the nuclei is taken into account by averaging the absorption cross section over molecular configurations generated by path integral simulations. We find that inclusion of quantum disorder is essential to bring the calculated spectra in close agreement with experiment. In particular, the intensity of the pre-edge feature, a spectral signature of broken and distorted hydrogen bonds, is accurately reproduced, in water and ice, only when quantum nuclei are considered. The effect of the local fields is less important but non negligible, particularly in ice

DECISION SUPPORT SYSTEMS: ISSUES AND PERSPECTIVES

Information Systems Working Papers Serie

Estudo comparativo de dois métodos de arraste principal do desbaste de Pinus taeda L.

Desempenho e custos na operação de arraste principal de dois tratores agrícolas com implementos diferentes foram submetidos a uma análise crítica, em uma plantação de Pinus taeda, com nove anos de idade e desbastada de forma sistemática e seletiva. A pesquisa foi instalada na Fazenda Monte Alegre, município de Telêmaco Borba, PR. Foram testados tratores do tipo MF 265 e os seguintes implementos de arraste: a) barra com fendas para engatar correntes, de segurar feixes de fustes, e b) pinça hidráulica traseira e lâmina hidráulica na frente. Sob as mesmas condições de distância e volume arrastado, os rendimentos foram similares, porém apresentaram grandes diferenças, quando baseados em volumes médios da carga. O trator com barra e correntes apresentou um volume médio de 0,8 m3 por ciclo e, numa distância média de 200 m, um rendimento de 6,85 m3/h, a um custo de Cr$60,80/m3. O trator com pinça hidráulica e lâmina dianteira, sob as mesmas condições de arraste, porém com um volume médio por ciclo de 0,5 m3, atingiu um rendimento de 5,39 m3/h, a um custo de Cr$ 82,10/m3. Sob as condições testadas, convém utilizar o trator com barra quando houver disponibilidade de mão-de-obra, pois arrasta maior volume de madeira por unidade de tempo a um custo mais baixo e com um grau de mecanização menor, portanto menos susceptível a falhas mecânicas. A exigência de maior tempo de oficina, com consertos e manutenção, em função da necessidade do equipamento, reduz a produção média anual em 35%, aproximadamente, no caso do trator com pinça. Detectaram-se, em ambos os métodos, grandes possibilidades de racionalização e, por conseguinte, de redução dos custos de arraste entre 24 e 27%

A Workflow-centric Study of Organizational Knowledge Distribution

Organizations require mechanisms to efficiently distribute knowledge such as news releases, seminar announcements, and memos. While the machinery for information storage, manipulation. and retrieval exists, research dealing directly with knowledge distribution in an organizational context is scarce. In this paper, we address this need by first examining the pros and cons of the conventional "mailing lists" approach and then proposing new workflow mechanisms that improve the efficiency and effectiveness of knowledge distribution. The main contributions of this study include: (I) a workflow perspective on organizational knowledge distribution. (2) workflow analysis of two new knowledge distribution methods based on dynamic mailing lists and profile matching, respectively, and (3) a new way of matching knowledge supply and demand that extends existing information filtering algorithms.Information Systems Working Papers Serie

X-Ray Detection of Transient Magnetic Moments Induced by a Spin Current in Cu

We have used a MHz lock-in x-ray spectro-microscopy technique to directly detect changes of magnetic moments in Cu due to spin injection from an adjacent Co layer. The elemental and chemical specificity of x-rays allows us to distinguish two spin current induced effects. We detect the creation of transient magnetic moments of $3\times 10^{-5}$ $\mu_\mathrm{B}$ on Cu atoms within the bulk of the 28 nm thick Cu film due to spin-accumulation. The moment value is compared to predictions by Mott's two current model. We also observe that the hybridization induced existing magnetic moments on Cu interface atoms are transiently increased by about 10% or $4\times 10^{-3}$ $\mu_\mathrm{B}$. This reveals the dominance of spin-torque alignment over Joule heat induced disorder of the interfacial Cu moments during current flow

SIGPAM Workshop on Process Automation and Management

The trend towards e-business is increasing the complexity of intra-organizational and inter-organizational processes. To accommodate these needs, organizations must integrate their services in real time to attract and maintain customers. In the last few years, process automation and management have become a central theme in many businesses. Research areas addressing problems in this domain include: electronic commerce, business process reengineering, enterprise application integration, knowledge process management, groupware, workflow automation, electronic markets, and computer supported collaborative work. These areas have unique research approaches, but have a common interest in advancing process automation to support intra-organizational and inter-organizational work in the Internet era. Consequently, there is a great need to bring together researchers with diverse backgrounds to discuss process-related topics. The objective of this workshop is to provide a forum for researchers and practitioners interested in process automation and management to meet and exchange research ideas and results. The workshop promotes a range of research issues, though not limited to: · Business process facilitation in distributed environments · Change management in highly automated business processes · Integration of business processes in both intra- and inter-enterprises · Methodologies and tools of process automation and management · Managing business processes on the Web · Process aware system security · Process centric model driven architectures · Process flexibility, interoperability, and scalability · Process-driven knowledge delivery · Theories of conceptual, logical, and physical process modeling · Wireless process management systems · Workflow automation and management for virtual enterprises · Workflow-centric component-based software engineerin