The NESSUS finite element code

The objective of this development is to provide a new analysis tool which integrates the structural modeling versatility of a modern finite element code with the latest advances in the area of probabilistic modeling and structural reliability. Version 2.0 of the NESSUS finite element code was released last February, and is currently being exercised on a set of problems which are representative of typical Space Shuttle Main Engine (SSME) applications. NESSUS 2.0 allows linear elastostatic and eigenvalue analysis of structures with uncertain geometry, material properties and boundary conditions, which are subjected to a random mechanical and thermal loading environment. The NESSUS finite element code is a key component in a broader software system consisting of five major modules. NESSUS/EXPERT is an expert system under development at Southwest Research Institute, with the objective of centralizing all component-specific knowledge useful for conducting probabilistic analysis of typical Space Shuttle Main Engine (SSME) components. NESSUS/FEM contains the finite element code used for the structural analysis and parameter sensitivity evaluation of these components. The task of parametrizing a finite element mesh in terms of the random variables present is facilitated with the use of the probabilistic data preprocessor in NESSUS/PRE. An external database file is used for managing the bulk of the data generated by NESSUS/FEM

Tuning paramagnetic spin-excitations of single adatoms

Around 50 years ago, Doniach [Proc. Phys. Soc. 91, 86 (1967)] predicted the existence of paramagnons in nearly ferromagnetic materials, recently measured in bulk Pd [Phys. Rev. Lett. 105, 027207 (2010)]. Here we predict the analogous effect for single adatoms, namely paramagnetic spin-excitations (PSE). Based on time-dependent density functional theory, we demonstrate that these overdamped excitations acquire a well-defined peak structure in the meV energy region when the adatom's Stoner criterion for magnetism is close to the critical point. In addition, our calculations reveal a subtle tunability and enhancement of PSE by external magnetic fields, exceeding by far the response of bulk paramagnons and even featuring the atomic version of a quantum phase transition. We further demonstrate how PSE can be detected as moving steps in the $\mathrm{d}I/dV$ signal of state-of-the-art inelastic scanning tunneling spectroscopy, opening a potential route for experimentally accessing fundamental electronic properties of non-magnetic adatoms, such as the Stoner parameter.Comment: 6 pages, 3 figure

Searching for unknown open clusters in the Tycho-2 catalog

We present 11 new open cluster candidates found in a systematic search for unknown star clusters using the astrometric and photometric data included in the Tycho2 catalog. The possible existence of these stellar aggregates is supported by the analysis of proper motions, color-magnitude diagrams, stellar density distributions, and by the visual inspection of the Digitized Sky Survey (DSS) plates. With these tools we were able to determine mean absolute proper motions as well as preliminary reddenings, distances and ages for the majority of the candidates. We found that most of them are possibly nearby (closer than about 600 pc) open clusters never studied before.Comment: 14 pages, 6 figures. Accepted by A&

Homogeneous metallicities and radial velocities for Galactic globular clusters. II. New CaT metallicities for 28 distant and reddened globular clusters

Although the globular clusters in the Milky Way have been studied for a long time, a significant fraction of them lack homogeneous metallicity and radial velocity measurements. In an earlier paper we presented the first part of a project to obtain metallicities and radial velocities of Galactic globular clusters from multiobject spectroscopy of their member stars using the ESO Very Large Telescope. In this paper we add metallicities and radial velocities for a new sample of 28 globular clusters, including in particular globular clusters in the MW halo and the Galactic bulge. Together with our previous results, this study brings the number of globular clusters with homogeneous measurements to $\sim 69$ \% of those listed in the W. Harris' catalogue. As in our previous work, we have used the CaII triplet lines to derive metallicities and radial velocities. For most of the clusters in this study, this is the first analysis based on spectroscopy of individual member stars. The metallicities derived from the CaII triplet are then compared to the results of our parallel study based on spectral fitting in the optical region and the implications for different calibrations of the CaII triplet line strengths are discussed. We also comment on some interesting clusters and investigate the presence of an abundance spread in the globular clusters here. A hint of a possible intrinsic spread is found for NGC 6256, which therefore appears to be a good candidate for further study.Comment: 13 pages, 9 figures, accepted for publication in Astronomy and Astrophysic

Levantamento e conservação da mastofauna em um remanescente da floresta ombrófila mista do Estado do Paraná, Brasil.

Resumo

Chuva de sementes e ciclagem de nutrientes no Parque Estadual Vila Rica do Espírito Santo, Fênix, PR.

Organizado por Patricia Póvoa de Mattos, Celso Garcia Auer, Rejane Stumpf Sberze, Katia Regina Pichelli e Paulo César Botosso

Levantamento e conservação da mastofauna em um remanescente de floresta ombrófila mista, Paraná, Brasil.

A Floresta Ombrófila Mista (FOM), também denominada Floresta com Araucária, recobria 37% da superfície do Paraná, mas hoje resta, nesse Estado, menos de 1% deste ecossistema florestal em estádio avançado de regeneração. Assim, o principal objetivo do presente estudo é contribuir com o conhecimento e a conservação da mastofauna paranaense, sobretudo das espécies que ocorrem na FOM. O trabalho de campo foi conduzido na área da Embrapa Florestas (25º19? S ? 49º09? W), que possui 301 ha, dos quais 105 ha são recobertos por FOM primária alterada e os 196 ha restantes o são por vegetação secundária e por plantios monoespecíficos de espécies florestais. Os registros de mamíferos foram realizados duas vezes por semana entre abril de 2003 e fevereiro de 2004, por meio de métodos diretos e indiretos que incluíram registros visuais, análise de vestígios, coleta de animais mortos, caçados ou atropelados, entrevistas e trabalho museológico. Juntas, estas técnicas revelaram a presença de 27 espécies de mamíferos, um número subestimado, uma vez que as espécies de pequeno porte foram subamostradas. Entretanto, a presença de espécies raras e/ou ameaçadas na área de estudo, como Cabassous tatouay, Mimon bennettii, Leopardus triginus, L. wiedii e Mazama spp., reforçam a importância de pequenos remanescentes florestais para a conservação dos mamíferos da FOM do Estado do Paraná