Stellar Chemical Abundances: In Pursuit of the Highest Achievable Precision

The achievable level of precision on photospheric abundances of stars is a major limiting factor on investigations of exoplanet host star characteristics, the chemical histories of star clusters, and the evolution of the Milky Way and other galaxies. While model-induced errors can be minimized through the differential analysis of spectrally similar stars, the maximum achievable precision of this technique has been debated. As a test, we derive differential abundances of 19 elements from high-quality asteroid-reflected solar spectra taken using a variety of instruments and conditions. We treat the solar spectra as being from unknown stars and use the resulting differential abundances, which are expected to be zero, as a diagnostic of the error in our measurements. Our results indicate that the relative resolution of the target and reference spectra is a major consideration, with use of different instruments to obtain the two spectra leading to errors up to 0.04 dex. Use of the same instrument at different epochs for the two spectra has a much smaller effect (~0.007 dex). The asteroid used to obtain the solar standard also has a negligible effect (~0.006 dex). Assuming that systematic errors from the stellar model atmospheres have been minimized, as in the case of solar twins, we confirm that differential chemical abundances can be obtained at sub-0.01 dex precision with due care in the observations, data reduction and abundance analysis.Comment: Accepted for publication in ApJ; 13 pages, 6 figures, 7 table

Shifting to green economy: Hype or hope for entrepreneurs into medicinal and aromatic plants?

This research aimed at finding out if rural development concerning medicinal and aromatic plants (MAP), in Portugal, was sufficiently consolidated to be considered an alternative lifestyle. Secondary data collected from a panel of 12 high-level experts enabled to picture the sector. Operations were the core knowledge area that helped to find out the implementation of the existing social platform into a technological solution to support a virtual collaborative effort among the stakeholders, as the main requirement to consolidate the sector. The required role of State was also defined as holistic, integrative, supportive, despite not-regulative, to implement a broad MAP policy

Creative Teaching of New Product Development to Operations Managers

New Product Development (NPD) has got its roots on an Engineering background. Thus, one might wonder about the interest, opportunity, contents and delivery process, if students from soft sciences were involved. This paper addressed «What to teach?» and «How to do it?», as the preliminary research questions that originated the introduced propositions. The curriculum-developer model that was purposefully chosen to adapt the coursebook by pursuing macro/micro strategies was found significant by an exploratory qualitative case study. Moreover, learning was developed and value created by implementing the institutional curriculum through a creative, hands-on, experiencing, problem-solving, problem-based but organized teamwork approach. Product design of an orange squeezer complying with ill-defined requirements, including drafts, sketches, prototypes, CAD simulations and a business plan, plus a website, written reports and presentations were the deliverables that confirmed an innovative contribution towards research and practice of teaching and learning of engineering subjects to non-specialist operations managers candidates

Specific heat amplitude ratios for anisotropic Lifshitz critical behaviors

We determine the specific heat amplitude ratio near a $m$-axial Lifshitz point and show its universal character. Using a recent renormalization group picture along with new field-theoretical $\epsilon_{L}$-expansion techniques, we established this amplitude ratio at one-loop order. We estimate the numerical value of this amplitude ratio for $m=1$ and $d=3$. The result is in very good agreement with its experimental measurement on the magnetic material $MnP$. It is shown that in the limit $m \to 0$ it trivially reduces to the Ising-like amplitude ratio.Comment: 8 pages, RevTex, accepted as a Brief Report in Physical Review

Using multiple related ontologies in a fuzzy information retrieval model.

With the Semantic Web progress many independently developed distinct domain ontologies have to be shared and reused by a variety of applications. The use of ontologies in information retrieval applications allows the retrieval of semantically related documents to an initial users´ query. This work presents a fuzzy information retrieval model for improving the document retrieval process considering a knowledge base composed of multiple domain ontologies that are fuzzy related. Each ontology can be represented independently as well as their relationships. This knowledge organization is used in a novel method to expand the user initial query and to index the documents in the collection. Experimental results show that the proposed model presents better overall performance when compared with another fuzzy-based approach for information retrieval.SBIA 2008

Susceptibility Amplitude Ratios Near a Lifshitz Point

The susceptibility amplitude ratio in the neighborhood of a uniaxial Lifshitz point is calculated at one-loop level using field-theoretic and $\epsilon_{L}$-expansion methods. We use the Schwinger parametrization of the propagator in order to split the quadratic and quartic part of the momenta, as well as a new special symmetry point suitable for renormalization purposes. For a cubic lattice (d = 3), we find the result $\frac{C_{+}}{C_{-}} = 3.85$.Comment: 7 pages, late

Seleccion de especies y procedencias del genero Eucalyptus para la region costera de Bahia, Brasil.

Con el objetivo de evaluar y seleccionar las mejores especies y/o procedencias de Eucalyptus para la region costera del Estado de Bahia (Brasil), el presente trabajo fue establecido en la Hacienda Buri, de la empresa Reflora/Ferbasa, provincia de Pojuca, Estado de Bahia, ubicada entre las coordenadas 12ø2S~51"Lat. S y 38ø19~40"Long. W, con altitud respecto al nivel del mar de 55 m. La precipitacion media anual es de 1.200 mm, concentrada entre los meses de abril y julio, con temperatura media de 25øC. Los suelos son acidos y de baja fertilidad natural. Los plantones fueron producidos en vivero de la Ernbrapa Semi-Arido, en Petrolina-PE, y conducidos al campo con altura media de 25 cm y plantados con espaciado de 3,0 m x 1,33 m, sin abono de fundacion. Fueron testadas cinco procedencias de E. urophylla, cuatro de E. camaldulensis, tres de E. brassiana y E. pellita, dos de E. citriodora, E. grandis y E. tereticornis y una de E. drepanophylla. Ei diseflo estadistico fue el de bloques al azar, con parcelas en lineas de cinco plantas, con diez repeticiones. En la evaluacion a los 30 dias del plantio, fue observado 100% de supervivencia en todas las especies y buen desempeflo silvicultural sin problemas fitosanitarios. A los 8 meses de edad los resultados apuntan variaciones significativas para la altura y supervivencia. Las especies/procedencias de mayor desarrollo en la region de Pojuca-BA, fueron E. urophylla, Proc. 14540, E. tereticornis Proc. CPATSA, E. grandis Proc. Rio Claro-SP, E. camaldulensis Proc. 14517, con alturas de 3,94; 3,64; 3,51; 3,46 y 3,45 m respectivamente, y estadisticamente superiores a las demas, con supervivencia por encima de 83%

Critical exponents from parallel plate geometries subject to periodic and antiperiodic boundary conditions

We introduce a renormalized 1PI vertex part scalar field theory setting in momentum space to computing the critical exponents $\nu$ and $\eta$, at least at two-loop order, for a layered parallel plate geometry separated by a distance L, with periodic as well as antiperiodic boundary conditions on the plates. We utilize massive and massless fields in order to extract the exponents in independent ultraviolet and infrared scaling analysis, respectively, which are required in a complete description of the scaling regions for finite size systems. We prove that fixed points and other critical amounts either in the ultraviolet or in the infrared regime dependent on the plates boundary condition are a general feature of normalization conditions. We introduce a new description of typical crossover regimes occurring in finite size systems. Avoiding these crossovers, the three regions of finite size scaling present for each of these boundary conditions are shown to be indistinguishable in the results of the exponents in periodic and antiperiodic conditions, which coincide with those from the (bulk) infinite system.Comment: Modified introduction and some references; new crossover regimes discussion improved; Appendixes expanded. 48 pages, no figure