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

Modelação matemática da variação da temperatura do pé

Existem doenças que afetam diretamente a planta do pé, podendo ser um fator de elevada importância na qualidade de vida do indivíduo. Sabe-se que a presença de uma dada doença na planta do pé poderá afetar a normal distribuição da temperatura na planta do pé. Este estudo pretende identificar as principais características da distribuição da temperatura na planta de pés saudáveis. Com esse objetivo, foram testadas quatro modelações matemáticas para estimar a matriz de temperatura obtida através de diversas imagens termográficas da planta do pé saudável de diversos indivíduos. Os problemas a resolver pertencem à classe de problemas de otimização não linear com restrições

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

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

Estudo da variação da temperatura na planta do pé

Como é de conhecimento comum, existem doenças que afetam diretamente a planta do pé, como é o caso da diabetes mellitus, que pode levar ao pé diabético. Perante este facto, pode afirmar-se que a locomoção dos indivíduos que apresentam esta doença está em risco e torna-se muitas vezes dolorosa, o que afeta a qualidade de vida dos mesmos. De forma a ajudar na prevenção, e em possíveis diagnósticos alternativos para a identificação precoce de doenças desta categoria, está a ser realizado um estudo onde se comparam imagens termográficas de pés diabéticos com pés saudáveis, uma vez que a presença deste tipo de doenças na planta do pé pode conduzir a alterações na distribuição da temperatura do pé. Neste estudo pretende- -se identificar as variações dessa distribuição da temperatura nos indivíduos e tentar classificá-las de forma a verificar se o indivíduo possui, ou não, uma possível patologia, mesmo que esta não seja visível a olho nu.info:eu-repo/semantics/publishedVersio