1,440 research outputs found

    DETERMINANTS OF ARGENTINEAN WINE PRICES IN THE U.S. MARKET

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    A hedonic price function for Argentinean wines in the U.S market is estimated in order to evaluate the effect of the most important attributes of wine on price. Results show that labeling practices and the choice of the right wine quality attributes are far more influential on price than expert panel opinions or oenological wine improvements such as aging.wine prices, Argentinean wine, hedonic price model, Demand and Price Analysis,

    ‘A double-edged sword. This is powerful but it could be used destructively’: Perspectives of early career education researchers on learning analytics

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    Learning analytics has been increasingly outlined as a powerful tool for measuring, analysing, and predicting learning experiences and behaviours. The rising use of learning analytics means that many educational researchers now require new ranges of technical analytical skills to contribute to an increasingly data-heavy field. However, it has been argued that educational data scientists are a ‘scarce breed’ (Buckingham Shum et al., 2013) and that more resources are needed to support the next generation of early career researchers in the education field. At the same time, little is known about how early career education researchers feel towards learning analytics and whether it is important to their current and future research practices. Using a thematic analysis of a participatory learning analytics workshop discussions with 25 early career education researchers, we outline in this article their ambitions, challenges and anxieties towards learning analytics. In doing so, we have provided a roadmap for how the learning analytics field might evolve and practical implications for supporting early career researchers’ development

    Determining the Mechanism of Yield Stability in Alfalfa

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    Year-to-year stability of crop yields is important for farmers and, hence, is an important goal of plant breeding programs. Especially in perennial crops like alfalfa, farmers need to know that they can count on consistent yields over a period of three or more years. Alfalfa varieties are composed of a population of many genetically distinct plants (or genotypes), unlike corn hybrids or soybean lines, which are genetically uniform

    Trace Mineral Leaching from Equine Compost

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    Mineral leaching from compost can be environmentally disruptive. Little information is available regarding trace mineral leaching from equine-sourced compost. The objective of this study was to quantify the mineral content and leaching potential of compost produced from feces of horses fed different amounts and forms (organic or inorganic) of trace minerals. Nine horses were fed three treatments in a 3 × 3 replicated Latin Square design. The dietary treatments were provided as a daily pellet: CON (pellet without added trace minerals), ING (added inorganic trace minerals), and ORG (added organic trace minerals). The added trace minerals were Co, Cu, Mn, and Zn. Feces were collected from each horse after a 16-day feeding period, combined with straw, composted, and then subjected to simulated rainfall to measure mineral mobility. Concentrations of Co, Cu, Mn, and Zn were greater in ING and ORG compared to CON compost (p \u3c 0.05); additionally, ING had greater Zn than ORG compost (p \u3c 0.05). More Cu leached from ING and ORG compared to CON (p \u3c 0.05). The most Zn leached from ING, followed by ORG, and the least amount leached from CON compost (p \u3c 0.05). Dietary trace mineral intake affected the trace mineral concentration in the compost and amount available to leach during rainfall events

    Agricultural potential in Latin America and Caribbean for biofuels for transport

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    93 p.The present study presents a general assessment of the productive capacity of Latin American countries for producing biomass1. Biomass can be transformed in secondary liquid energy carriers like biodiesel and bioethanol, fossil fuels substitutes. The document begins with the description of the characteristics of currently used energy crops2 world wide. A specific analysis of Latin American productive conditions was then carried out to determine if the region has the potential to reach, at least, 5% blend levels3. The land availability and energy crop yields for biomass production were also projected for the year 2025, together with two alternative raw materials i.e. waste crops and field residues. Finally, the effects of a demand increase; producer subsidy and price support on energy crop markets were assessed. It was determined that most of Latin American countries could produce sufficient biomass to reach 5% blends. There is land availability for biomass production in 2025 mostly in South American countries. Potentially attainable blends of most Latin American countries for the year 2025, using biomass from agricultural energy crops, are between 30% and 91% for biodiesel, and between 20% and 206% for bioethanol. Blend estimates from forestry biomass are even higher and from residues are much lower. The “price support” measure causes the highest net welfare gain in Latin America countries (1.844 Mill. US)aswellasintheRestoftheWorld(1.623Mill.US) as well as in the Rest of the World (1.623 Mill. US) , whereas the demand shift provokes in the Rest of the World a net welfare loss of 761 Mill. US$

    Carbon monoxide detector

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    A sensitive carbon monoxide detector, developed specifically for spacecraft use, is described. An instrument range of 0 to 60 ppm CO in air was devised. The fuel cell type detector is used as a highly sensitive electrolysis cell for electrochemically detecting gases. The concept of an electrochemical CO detector is discussed and the CO oxidation behavior in phosphoric and sulfuric acid electrolytes is reported

    Effects of Chloride Fertilization on Alfalfa Cation-Anion Content

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    Producing low potassium (K) forages has increased due to demand for such forages in the dairy business. In the month prior to calving, a fairly anionic diet is recommended in dairy cows to avoid milk fever, a term used for hypocalcemia, a deficiency in plasma calcium (Ca) at the onset of lactation in dairy cows. This bovine disease affects approximately 6 to 8% of all U.S. dairy cows annually, directly costing the dairy industry up to $200 million/year. As dairy cows enter the lactation stage prior to calving, large amounts of calcium leave the blood and enters milk faster than it can be replaced. This decreased calcium concentration in the blood lowers the pH, causing nerve disorders, muscle weakness, loss of appetite, paralysis, and subsequent death if not treated immediately. Treatment typically includes an intravenous dosage of a calcium solution, usually including a mixture of phosphorus (P), K, magnesium (Mg) and dextrose. Cationic diets, such as forages high in potassium (\u3e2.5%) are meant for the post-calving, lactation stage because of the dairy cow’s diet requirement in producing milk

    Pairwise Discriminative Speaker Verification in the I-Vector Space

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    This work presents a new and efficient approach to discriminative speaker verification in the i-vector space. We illustrate the development of a linear discriminative classifier that is trained to discriminate between the hypothesis that a pair of feature vectors in a trial belong to the same speaker or to different speakers. This approach is alternative to the usual discriminative setup that discriminates between a speaker and all the other speakers. We use a discriminative classifier based on a Support Vector Machine (SVM) that is trained to estimate the parameters of a symmetric quadratic function approximating a log-likelihood ratio score without explicit modeling of the i-vector distributions as in the generative Probabilistic Linear Discriminant Analysis (PLDA) models. Training these models is feasible because it is not necessary to expand the i-vector pairs, which would be expensive or even impossible even for medium sized training sets. The results of experiments performed on the tel-tel extended core condition of the NIST 2010 Speaker Recognition Evaluation are competitive with the ones obtained by generative models, in terms of normalized Detection Cost Function and Equal Error Rate. Moreover, we show that it is possible to train a gender- independent discriminative model that achieves state-of-the-art accuracy, comparable to the one of a gender-dependent system, saving memory and execution time both in training and in testin

    Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust

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    Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12 degrees N, 49 degrees W and M2 at 14 degrees N, 37 degrees W) collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic. The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus) but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241 x 10(7) +/- 76 x 10(7) coccoliths m(-2) d(-1) at station M4 compared to only 66 x 10(7) +/- 31 x 10(7) coccoliths m(-2) d(-1) at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, favoured by the westward deepening of the thermocline and nutricline. Still, most UPZ species also contributed to higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. Such was the case of two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi in January and April 2013 at M4, indicating a fast response to the nutrient enrichment of the UPZ, probably by wind-forced mixing. Later, increased fluxes of G. oceanica and E. huxleyi in October-November 2013 coincided with the occurrence of Amazon-River-affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust flux peaks, we propose a scenario in which atmospheric dust also provided fertilizing nutrients to this area. Enhanced surface buoyancy associated with the river plume indicates that the Amazon acted not only as a nutrient source, but also as a surface density retainer for nutrients supplied from the atmosphere. Nevertheless, lower total coccolith fluxes during these events compared to the maxima recorded in November 2012 and July 2013 indicate that transient productivity by opportunistic species was less important than "background" tropical productivity in the equatorial North Atlantic. This study illustrates how two apparently similar sites in the tropical open ocean actually differ greatly in ecological and oceanographic terms. The results presented here provide valuable insights into the processes governing the ecological dynamics and the downward export of coccolithophores in the tropical North Atlantic.Netherlands Organization for Scientific Research (NWO) [822.01.008]; European Research Council (ERC) [311152]; University of Bremen; European Union [600411]info:eu-repo/semantics/publishedVersio

    The development of a measurement instrument to measure the quality of internet investor relations

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    The purpose of this study was to develop a measurement instrument to measure the quality of Internet investor relations (IIR). This study will aid future research to examine IIR and provide guidance to companies in the development of an IIR strategy. The development of the instrument was based on best practice guidelines issued by the Investor Relations Society, an extensive literature review and a pilot study. The result was a measurement instrument that consists of 346 attributes. Quality is assessed by measuring content as widely as possible, by including attributes to measure the accessibility, navigation and timeliness of information, and by allowing for the measurement of attributes as being partially available based on breadth, usability and timeliness considerations. The reliability and validity of the measurement instrument was confirmed on the basis of the measurement results of a sample of 85 JSE-listed companies
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