3,593 research outputs found
The LSTS open-source communication and autonomy software: enabling networked vehicle systems to find track, and sample dynamic features of the ocean
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Impact of gamma irradiation on nutritional composition and antioxidant activity of Aloysia citriodora Paláu and Melittis melissophyllum L.
Aloysia citriodora Paláu and Melittis melissophyllum L. are examples of plants that have been used for medicinal purposes as dietary supplements or infusions [1,2]. The incorporation of plant extracts/compounds in pharmaceuticals has been increasing. However, due to the high demand of the pharmaceutical industry for the use of raw materials with good microbiological quality, decontamination techniques should be applied. Irradiation arises as an alternative [3]. The aim of this work was to evaluate the effects of gamma irradiation (0 kGy – control, 1 kGy and 10 kGy) on nutritional value and antioxidant activity of A. triphylla and M. melissophyllum. The nutritional value was determined following official analysis methodologies; free sugars were analyzed by high performance liquid chromatography coupled to a refraction index detector (RI-HPLC), fatty acids by gas chromatography coupled with a flame ionization detector (GC-FID), and tocopherols by HPLC-fluorescence. The antioxidant properties of the infusions were evaluated through free radicals scavenging activity, reducing power and inhibiting of lipid peroxidation. In general, gamma irradiation protected fructose, trehalose, and the major fatty acids found in A. citriodora. Furthermore, the dose of 10 kGy protected oxalic, malic, and quinic acids, as also protein and ash levels and revealed the highest antioxidant activity for the majority of the assays. The dose of 1 kGy protected all isoforms of tocopherols detected in the plant. Regarding M. melissophyllum, it was concluded that the control sample (non-irradiated) showed the highest antioxidant activity, as well as the highest levels of -tocopherol. However, in general, it was observed that a dose of 10 kGy maintains the nutritional properties of the plant, such as protein and ash levels. Thus, we can conclude that irradiation is a decontaminating technique that does not interfere drastically with the chemical properties of the studied plants.Proder (Project nº 53514, AROMAP) and to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). The authors are also grateful to “MaisErvas - Aromáticas e Medicinais” for samples providing
Rare earth elements in gneiss regoliths in southern Minas Gerais, Brazil
Regolith characterization in its entirety is particularly difficult in gneissic regoliths due to the heterogeneity of their rock structure. Rare earth elements (REE) are a useful tool in helping understand the evolution of regoliths. This study relates the mineralogy and weathering indexes of three gneisses regoliths (P1-leucocratic, P2-mesocratic and P3-melanocratic gneisses) to the distribution of REE at depth. In soil, clay activity, iron and manganese oxides, CaO, SiO2, P2O5, TiO2, Fe2O3, and MgO showed high positive correlation with REE. The absolute content of REE was enriched in mafic minerals. At the interface between the soil and saprolite, the sum of absolute REE content was greater in soil than in saprolite in P1, while the opposite pattern was found in P2 and P3. The sums of absolute REE in the whole profiles did not overlap between P1, P2 and P3, and the absolute concentration of Gadolinium (Gd) differentiated the three gneisses in all and every horizon/layer of their regoliths without overlapping values. Normalized REE content was greater in the subsurface of P1 due to Eu content in plagioclase, and fractionation had less variation when estimated by Light REE / Heavy REE (LREE/HREE) than by La/Yb, since the variation in REE is great in gneisses (due to the segregation of minerals into bands), and had low levels of association with the Chemical Index of Alteration (CIA) and the Weathering Index of Parker (WIP)
Efeito dos investimentos nos fundamentos e na reação de mercado de empresas brasileiras pré-operacionais e operacionais do período de 2006 a 2012
This paper provides evidence on the market reaction to corporate investment decisions whose shareholder value is largely attributed to growth options. The exploratory research raised pre-operational companies and their operational pairs on the same economy segments. It had the purpose of investigating the existence of statistical differentiation from financial indicators that reflect the installed assets and growth assets, and then study the market reaction to changes in fixed assets as a signaling element about investment decisions. The formation process of operational assets and shareholder value almost exclusively dependent on asset growth stands out in the pre-operational companies. As a result, differentiation tests confirmed that the pre-operational companies had their value especially derived on growth options. The market reaction was particularly bigger in pre-operational companies with abnormal negative stock returns, while the operational companies had positive returns, which may indicate that the quality of the investment is judged based on the financial disclosure. Additionally, operational companies' investors await the disclosure to adjust their prices. We conclude that the results are consistent with the empirical evidence and the participants in financial markets to long-term capital formation investments should give that special attention.O trabalho fornece evidências sobre a reação do mercado às decisões de investimento de empresas cujo valor acionário é predominantemente atribuído às opções de crescimento. A pesquisa exploratória levantou empresas pré-operacionais e seus pares operacionais dos mesmos segmentos da economia. Investigou-se a existência de diferenciação estatística a partir de indicadores financeiros que refletissem os ativos instalados e os ativos de crescimento para, em seguida, estudar a reação do mercado às variações do ativo não circulante como elemento de sinalização acerca das decisões de investimento. Destaca-se nas empresas pré-operacionais o processo de formação do ativo operacional e o valor acionário quase exclusivamente dependente dos ativos de crescimento. Como resultado, os testes de diferenciação confirmaram que as empresas pré-operacionais têm seu valor especialmente derivado das opções de crescimento. A reação do mercado foi maior nas empresas pré-operacionais, apresentando retornos anormais negativos, enquanto que nas operacionais tais retornos foram positivos, o que pode indicar que a qualidade do investimento é julgada a partir da divulgação financeira. Ademais, a divulgação é aguardada pelos investidores de empresas operacionais para ajustarem seus preços. Conclui-se que os resultados estão de acordo com as evidências empíricas e que atenção especial deva ser dada aos investimentos de formação de capital de longo prazo pelos participantes dos mercados financeiros.El trabajo proporciona evidencia sobre la reacción del mercado en las decisiones de inversión de las empresas, que el valor del accionista se atribuye en gran medida a opciones de crecimiento. La investigación exploratoria planteó empresas pre-operacionales y sus pares operativos en los mismos segmentos de la economía. Se investigó la existencia de diferenciación estadística de indicadores financieros que reflejan los activos instalados y activos de crecimiento para luego estudiar la reacción del mercado a los cambios en activos fijos como elemento de señalización sobre las decisiones de inversión. Se destaca en las empresas pre-operacionales del proceso de formación de los activos operativos y el valor del accionista depende casi exclusivamente en el crecimiento de los activos. Las pruebas confirmaron que el valor de las empresas pre-operacionales se deriva especialmente de las opciones de crecimiento. La reacción del mercado fue particularmente alto en las empresas pre-operacionales con rendimientos de las acciones negativas anormales, mientras que los otros tuvieron resultados positivos, lo que puede indicar que la calidad de la inversión se juzga basado en la divulgación de información financiera. Y la revelación es esperada por los inversores para ajustar sus precios. Los resultados son consistentes con la evidencia empírica y la atención especial se debe dar por los participantes en los mercados financieros a las inversiones de formación de capital a largo plazo
Deciphering a multi-event in a non-complex set of detrital zircon U–Pb ages from Carboniferous graywackes of SW Iberia
The determination of U–Pb ages from detrital zircons of sedimentary rocks using LA-ICP-MS has been widely
used for the purpose of provenance analysis. One problem that frequently arises is finding a population that
appears to be non-complex despite several perceptible age peaks in its spectrum. These peaks are qualitatively
defined by means of relative probability diagrams, or PDFs, but it is difficult to quantify their statistical significance
relative to a zircon forming multi-event. Thus, can a multi-event in a non-complex set of detrital zircon
U–Pb ages be deciphered and characterized?
The aim of this study is to attempt to provide an answer to this question by means of statistical analysis. Its
objectives are: a) to determine the best minimum number of zircon age populations (peaks), BmPs, b) for the
characterization of each peak in terms of age and event duration; c) to compare the results obtained from two
datasets showing similar zircon ages; and d) to demonstrate the usefulness of deciphering these BmPs. First,
cluster analysis is carried out, aimed at grouping zircon ages into a set of consistent clusters. A Gaussian Kernel
function is then fitted to each cluster and summed to obtain a theoretical PDFm (modeled probability density
function). Finally, the selected modeled PDFm (that built on the BmPs) is that which reports the lowest number
of peaks for which the difference as compared with the original gPDF (global probability density function) is
equal to or below 5%. Deciphered BmP peaks can be characterized and used for characterizing and providing
an understanding of related event(s).
A geological interpretation, based on the results obtained, is attempted. This includes a robust measure for
maximum age of deposition for both Cabrela and Mértola graywackes
Hand Posture Effects on Handedness Recognition as Revealed by the Simon Effect
We investigated the influence of hand posture in handedness recognition, while varying the spatial correspondence between stimulus and response in a modified Simon task. Drawings of the left and right hands were displayed either in a back or palm view while participants discriminated stimulus handedness by pressing either a left or right key with their hands resting either in a prone or supine posture. As a control, subjects performed a regular Simon task using simple geometric shapes as stimuli. Results showed that when hands were in a prone posture, the spatially corresponding trials (i.e., stimulus and response located on the same side) were faster than the non-corresponding trials (i.e., stimulus and response on opposite sides). In contrast, for the supine posture, there was no difference between corresponding and non-corresponding trials. Control experiments with the regular Simon task showed that the posture of the responding hand had no influence on performance. When the stimulus is the drawing of a hand, however, the posture of the responding hand affects the spatial correspondence effect because response location is coded based on multiple reference points, including the body of the hand
Analytical methods applied to assess the effects of gamma irradiation on color, chemical composition and antioxidant activity of Ginkgo biloba L
The extracts from the leaves of Ginkgo biloba are widely used in medicines and food supplements in order to overcome different health problems. To provide decontamination, irradiation is a safe and effective technique, particularly suitable to be integrated in quality control of the postharvest samples. In this study, different analytical methods were applied to assess the effects of gamma irradiation (1 and 10 kGy) in G. biloba color, chemical composition and antioxidant properties. Irradiation preserved macronutrients, fatty acids, γ- and δ-tocopherols, fructose, trehalose, quinic and shikimic acids. In particular, 1 kGy protected α-tocopherol, oxalic and malic acids contents, while 10 kGy decreased α-tocopherol, glucose, sucrose, oxalic and malic acids level. Nevertheless, this dose was the most effective for antioxidant activity. Overall, 1 kGy would be the recommended dose to maintain nutritional profile of G. biloba, protect specific molecules and also increase antioxidant activity of infusion and methanolic extracts prepared from its leaves.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). The authors are also grateful to Clarinda Paixão, from Américo Duarte Paixão Lda, for samples providing
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