954 resultados para Ore pellets


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A large class of special functions are solutions of systems of linear difference and differential equations with polynomial coefficients. For a given function, these equations considered as operator polynomials generate a left ideal in a noncommutative algebra called Ore algebra. This ideal with finitely many conditions characterizes the function uniquely so that Gröbner basis techniques can be applied. Many problems related to special functions which can be described by such ideals can be solved by performing elimination of appropriate noncommutative variables in these ideals. In this work, we mainly achieve the following: 1. We give an overview of the theoretical algebraic background as well as the algorithmic aspects of different methods using noncommutative Gröbner elimination techniques in Ore algebras in order to solve problems related to special functions. 2. We describe in detail algorithms which are based on Gröbner elimination techniques and perform the creative telescoping method for sums and integrals of special functions. 3. We investigate and compare these algorithms by illustrative examples which are performed by the computer algebra system Maple. This investigation has the objective to test how far noncommutative Gröbner elimination techniques may be efficiently applied to perform creative telescoping.

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Gu??a did??ctica que tiene como objetivo explicar los contenidos del programa y ofrecer pautas a profesores y tutores sobre las posibilidades de las t??cnicas de estudio aplicables en el marco escolar. La gu??a est?? estructurada en unidades did??cticas atendiendo no s??lo al individuo sino al colectivo de clase. Cada una de las unidades se compone de tres actividades y dos reflexiones. Los temas abordados son: t??cnicas y h??bitos de estudio; din??mica del grupo-clase; investigaciones en el aula. Bibliograf??a p. 112.

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PremessaSebbene numerosi studi prospettici, controllati e randomizzati abbiano dimostrato il successo della ventilazione non-invasiva a pressione positiva (NIV) in casi selezionati di insufficienza respiratoria acuta ipercapnica (IRA) in setting con intensità di cura differenti, i dati di pratica clinica relativi all’uso della NIV nel “mondo reale” sono limitati. Scopo Riportare i risultati della nostra esperienza clinica sulla NIV nell’IRA applicata nell’Unità di Terapia Semi-Intensiva Respiratoria (UTSIR) allocata all’interno dell’Unità Operativa di Pneumologia di Arezzo negli anni 1996-2006 in termini di: tollerabilità, effetti sui gas ematici, tasso di successo e fattori predittivi del fallimento.MetodiTrecentocinquanta dei 1484 pazienti (23.6%) consecutivamente ammessi per IRA nella nostra Unità Operativa di Pneumologia durante il periodo di studio hanno ricevuto la NIV in aggiunta alla terapia standard, in seguito al raggiungimento di criteri predefiniti impiegati di routine.RisultatiOtto pazienti (2.3%) non hanno tollerato la NIV per discomfort alla maschera, mentre i rimanenti 342 (M: 240, F: 102; età: mediana (interquartili) 74.0 (68.0-79.3) anni; BPCO: 69.3%) sono stati ventilati per >1 ora. I gas ematici sono significativamente migliorati dopo 2 ore di NIV (media (deviazione standard) pH: 7.33 (0.07) versus 7.28 (7.25-7.31), p<0.0001; PaCO2: 71.4 (15.3) mmHg versus 80.8 (16.6) mmHg, p<0.0001; PaO2/FiO2: 205 (61) versus 183 (150-222), p<0.0001). La NIV ha evitato l’intubazione in 285/342 pazienti (83.3%) con una mortalità ospedaliera del 14.0%. Il fallimento della NIV è risultato essere predetto in modo indipendente dall’Apache III (Acute Physiology and Chronic Health Evaluation III) score, dall’indice di massa corporea e dal fallimento tardivo della NIV (> 48 ore di ventilazione) dopo iniziale risposta positiva.ConclusioniSecondo la nostra esperienza clinica di dieci anni realizzata in una UTSIR, la NIV si conferma essere ben tollerata, efficace nel migliorare i gas ematici e utile nell’evitare l’intubazione in molti episodi di IRA non-responsivi alla terapia standard.

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Se presenta un análisis prospectivo del comportamiento de la oferta y la demanda del Mineral de Cobre en el Mundo, en Latinoamerica y en Colombia, creando diferentes escenarios con futuros posibles, consientes y detallados que servirán para entender la dinámica de mercado y la creación de estrategias de penetración, disminución de costos y aumento de productividad en compañías que operan tanto en países donde la industria del cobre se encuentra muy desarrollada, como en aquellos donde la explotación del mineral es todavía muy incipiente (Colombia).

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El proyecto consiste en la realización simultánea de los proyectos Elaboración de itinerarios literarios, Creación de una antología poética, y Hoy es el Día del Libro. Los objetivos son reflexionar, interpretar y analizar los textos literarios; aprender a investigar; valorar y respetar las normas de la comunicación; realizar tareas en grupo con actitudes solidarias y constructivas; reconocer y apreciar las producciones literarias que forman parte del patrimonio cultural; aceptar la diversidad de personas y culturas, para superar prejuicios y discriminaciones; aprender las normas para leer correctamente y la elaboración de fichas y resúmenes; adquirir hábitos de lectura; y crear producciones literarias. Las actividades son la lectura personal de textos por el alumnado; la elaboración de fichas de lectura con los aspectos de estudio por grupos; elaboración y visita de un itinerario literario; consulta en la biblioteca de textos poéticos; memorización y recitado expresivo e interpretativo de los poemas en el aula; elaboración de una antología con todos los poemas; selección de personas de la comunidad educativa para la lectura continuada de obras de Cervantes y de Shakespeare en el Día del Libro; concurso de relatos y poemas; elaboración de carteles sobre la biografía, aspectos históricos y fragmentos de las obras de Cervantes y de Shakespeare. La evaluación valora la lectura expresiva de textos, el uso correcto de la lengua oral, la observación de las normas de participación en clase, la identificación en textos e imágenes de expresiones discriminatorias y la búsqueda de alternativas para evitarlos, análisis de un poema, comentario de textos literarios, consulta de fuentes de información, y presentación de los trabajos con corrección. Se elaboran materiales, algunos incluidos en los anexos, como trabajos de los alumnos sobre Cervantes, Shakespeare y Baroja; la antología poética; antología poética creativa, con poemas de los alumnos; y obras premiadas en el concurso.

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Manual para todos los profesores que tratan con el trastorno de hiperactividad por déficit de atención. Su objetivo es proporcionar a los maestros información actualizada y una variedad de situaciones en que pueden desempeñar un papel activo para ayudar en los problemas de socialización que sufren los niños con TDAH, especialmente en lo que respecta a los compañeros, hermanos y padres.

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Günter Strauss is Ph.D. in geology from the University of Munich in 1965. He is a German living by long time in Spain. Naw he is a SAPEC High Advisser His doctoral thesis, submitted in 1965, with the title "About the Geology of the Province of pyrite Southwest of the Iberian Peninsula and its oil fields, especially in the pyrite mine Louzal - Portugal" Systematized the term" Iberian Pyrite Belt ", called for the deposits of iron ore cuprífera, rich in sulfur and other metallic minerals, which occurs between the rivers Sado and Guadalquivir, where they settled several mining complexes, of Louzal, Rio Tinto, through Castro Verde, Santo Domingo and Tharsis. Local mining tradition with an ancient where today seeks to preserve the legacy and memory of mining through measures to enhance equity. The result of work carried out Louzal then formed the basis of geological and documentary collection that has survived and has been proposed for cultural units under the activities of the mining museum Louzal. The richness and importance of this collection, consisting of several hundred documents, geological samples classified, minerals and cartography, comes from its presence Situ"In its state of preservation, that despite the various threats it is still within reach of their preservation, and the relative rarity of such collections, with the units of mining production. This communication aims to reveal the contribution of Mr Strauss for the formation of this collection and submit his proposal for cultural units, with the hope that those responsible for safeguarding them understand the need for its preservation and dissemination. So discuss the scientific and professional way Günter Strauss, a geologic formation of the estate of Mines Louzal, and the draft musealization proposition.

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In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by U-238 and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (<= 8.8 Bq/g) of U-238 Were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (<= 11 Bq/g) of Ra-226 were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution. (c) 2005 Elsevier Ltd. All rights reserved.

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Trace elements may present an environmental hazard in the vicinity of mining and smelting activities. However, the factors controlling trace element distribution in soils around ancient and modem mining and smelting areas are not always clear. Tharsis, Riotinto and Huelva are located in the Iberian Pyrite Belt in SW Spain. Tharsis and Riotinto mines have been exploited since 2500 B.C., with intensive smelting taking place. Huelva, established in 1970 and using the Flash Furnace Outokumpu process, is currently one of the largest smelter in the world. Pyrite and chalcopyrite ore have been intensively smelted for Cu. However, unusually for smelters and mines of a similar size, the elevated trace element concentrations in soils were found to be restricted to the immediate vicinity of the mines and smelters, being found up to a maximum of 2 kin from the mines and smelters at Tharsis, Riotinto and Huelva. Trace element partitioning (over 2/3 of trace elements found in the residual immobile fraction of soils at Tharsis) and soil particles examination by SEM-EDX showed that trace elements were not adsorbed onto soil particles, but were included within the matrix of large trace element-rich Fe silicate slag particles (i.e. 1 min circle divide at least 1 wt.% As, Cu and Zn, and 2 wt.% Pb). Slag particle large size (I mm 0) was found to control the geographically restricted trace element distribution in soils at Tharsis, Riotinto and Huelva, since large heavy particles could not have been transported long distances. Distribution and partitioning indicated that impacts to the environment as a result of mining and smelting should remain minimal in the region. (c) 2006 Elsevier B.V. All rights reserved.

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In January 1992, there was a major pollutant event for the River Canon and downstream with its confluence to the River Fal and the Fal estuary in the west Cornwall. This incident was associated with the discharge of several million gallons of highly polluted water from the abandoned Wheal Jane tin mine that also extracted Ag, Cu and Zn ore. Later that year, the Centre for Ecology and Hydrology (CBH; then Institute of Hydrology) Wallingford undertook daily monitoring of the River Canon for a range of major, minor and trace elements to assess the nature and the dynamics of the pollutant discharges. These data cover an 18-month period when there remained major water-quality problems after the initial phase of surface water contamination. Here, a summary is provided of the water quality found, as a backdrop to set against subsequent remediation. Two types of water-quality determinant grouping were observed. The first type comprises the determinants B, Cs, Ca, Li, K, Na, SO4, Rb and Sr, and their concentrations are positively correlated with each other but inversely correlated with flow. This type of water-quality determinant shows variations in concentration that broadly link to the normal hydrogeochemical processes within the catchment, with limited confounding issues associated with mine drainage. The second type of water-quality determinant comprises Al, Be, Cd, Ce, Co, Cu, Fe, La, Pb, Pr, Nd, Ni, Si, Sb, U, Y and Zn, and concentrations for all this group are positively correlated. The determinants in this second group all have concentrations that are negatively correlated with pH. This group links primarily to pollutant mine discharge. The water-quality variations in the River Camon are described in relation to these two distinct hydrogeochemical groupings. (C) 2004 Elsevier B.V All rights reserved.

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Poor glucose tolerance may be an under-researched contributory factor in the high (10% to 20%) pre-weaning mortality rate observed in pigs. Insulin resistance commences at around week 12 of gestation in the sow, although there are conflicting reports in the literature about the extent to which insulin resistance is modulated by maternal diet. The aim of the study was to determine the effects of supplementing the maternal diet with different dietary oils during either the first half or the second half of gestation on the glucose tolerance of the sow. Sows were offered the control (C: n = 5) diet as pellets or the C diet plus 10% extra energy (h = 16 per group) derived from either. (i) extra pellets; (ii) palm oil; (iii) olive oil; (iv) sunflower oil; or (v) fish oil. Experimental diets were fed during either the first (G1) or second (G2) half of gestation. A glucose tolerance test (GTT) was conducted on day 108 of gestation by administering 0.5g/kg glucose i.v. Blood samples were taken every 5 to 10 min for 90 min post administration. The change in body weight and backfat thickness during gestation was similar but both type and timing of dietary supplementation influenced litter size and weight. With the exception of the sunflower oil group, supplementing the maternal diet in G1 resulted in larger and heavier litters, particularly in mothers offered palm oil. Basal blood glucose concentrations tended to be more elevated in G1 than G2 groups, whilst plasma insulin concentrations were similar Following a GTT, the adjusted area under the curve was greater in G1 compared to G2 sows, despite no differences in glucose clearance. Maternal diet appeared to influence the relationship between glucose curve characteristics following a GTT and litter outcome. In conclusion, the degree of insulin sensitivity can be altered by both the period during which maternal nutritional supplementation is offered and the fatty acid profile of the diet.

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Eighty-eight multiparous sows were used to evaluate whether type and timing of oil supplementation during gestation influences the incidence of low birth weight (LBW). Sows were allocated (eight per treatment) commercial sow pellets (3 kg/d; control diet) or an experimental diet consisting of control diet plus 10 % extra energy in the form of excess pellets, palm oil, olive oil (OO), sunflower oil (SO) or fish oil; experimental diets were fed during either the first half (G1) or second half (G2) of gestation. Growth performance and endocrine profile of LBW ( < 1·09 kg) and normal birth weight (NBW; 1·46–1·64 kg) offspring were compared. Maternal dietary supplementation altered the distribution curve for piglet birth weight. SOG1 sows had a greater proportion of LBW piglets (P < 0·05), whilst it was reduced in the OOG1 group (P < 0·05). Growth rate of LBW piglets was lower compared with their NBW siblings (P < 0·05) when dietary supplementation was offered in G2 but were similar for G1. At birth, LBW offspring of supplemented animals possessed more fat compared with the control group (P < 0·05); LBW offspring of control animals exhibited a more rapid decline in fat free mass/kg prior to weaning. Plasma metabolites and insulin concentrations were influenced by maternal diet and birth weight. In conclusion, maternal dietary supplementation altered the distribution of piglet birth weights and improved the energy status of LBW piglets. Supplementation with MUFA during G1 reduced the incidence of LBW, whereas PUFA had the reverse effect.

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The objective of the present studies was to determine effects of basal dietary forage source on the response of milk fatty acid composition to an oil supplement based (2:1, respectively, w/w) on soybean oil and marine algae biomass oil high in cis-9, cis-12 C18:2n − 3 and C22:6n − 3, respectively. In Study 1, Hampshire × Dorset ewes (48) were randomly assigned to one of four treatments and 12 pens in a completely randomized design blocked on the basis of lambing date and number of lambs suckled. Control rations (60:40 forage:concentrate, dry matter (DM) basis) based on alfalfa pellets (AP) or corn silage (CS) were fed from lambing. Beginning at 22 days postpartum, three pens of ewes fed AP and three pens of ewes fed CS were supplemented with oil (30 g/kg of ration DM) in place of corn meal. Average ewe DM intake (DMI) and average daily gain (ADG) were measured weekly. Milk yield and composition were measured at 42 days postpartum. DMI was lower (P<0.02) for CS and for oil, but milk yield was not affected by forage source or oil supplementation. Milk fat content was higher for oil (P<0.10) and milk protein content was higher for AP (P<0.04). Total CLA concentration (g/100 g fatty acids) increased (P<0.01) with CS and oil, and the response to oil was greater for AP (P<0.04). Similarly, total trans-C18:1 and C22:6ω−3 concentrations were higher for CS and oil, but the response to oil was greater for CS (P<0.06 and P<0.01, respectively). In Study 2, the experiment was repeated using alfalfa haylage (AH) instead of AP. The DMI decreased (P<0.05) with oil feeding, but was not affected by forage source. Milk yield was decreased by feeding oil with AH, but not by feeding oil with CS (P<0.03). Milk fat content tended to be increased by feeding oil with AH, but tended to be decreased by feeding oil with CS (P<0.08). Total CLA concentration was increased (P<0.01) for AH versus CS and by oil, and the response to oil supplementation was greater for AH (P<0.01). In contrast, total trans-C18:1 concentration was higher for CS versus AH, with a greater response to oil for CS (P<0.05). Feeding marine oil increased the C22:6ω−3 (P<0.01) concentration, and the response was greater for AH (P<0.04). To further characterize the response of milk fat composition to dietary oil in ewes, a third study used six pens of three ewes each assigned to either the control CS diet used for Study 2 or the same diet supplemented with 45 g/kg (DM basis) of the oil mixture. Feeding oil had no effect on DMI, milk yield or milk fat concentration, but again increased (P<0.001) total trans-C18:1 and C22:6ω−3 concentrations and numerically increased (114%) total CLA concentration. Milk fatty acid composition responses to supplemental vegetable and marine oils were affected by forage source. Milk trans-C18:1 concentration was higher when CS was fed in Studies 1 and 2, but the effect of forage species on CLA concentration differed between studies, which may reflect differences in diet PUFA content and consumption, as well as amounts of dietary starch and fiber consumed. Despite large increases in trans-C18:1 concentration, milk fat content was not decreased by feeding unsaturated oils to ewes, even at diet levels of 45 g/kg of ration DM.

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Hydrogen spillover on carbon-supported precious metal catalysts has been investigated with inelastic neutron scattering (INS) spectroscopy. The aim, which was fully realized, was to identify spillover hydrogen on the carbon support. The inelastic neutron scattering spectra of Pt/C, Ru/C, and PtRu/C fuel cell catalysts dosed with hydrogen were determined in two sets of experiments: with the catalyst in the neutron beam and, using an annular cell, with carbon in the beam and catalyst pellets at the edge of the cell excluded from the beam. The vibrational modes observed in the INS spectra were assigned with reference to the INS of a polycyclic aromatic hydrocarbon, coronene, taken as a molecular model of a graphite layer, and with the aid of computational modeling. Two forms of spillover hydrogen were identified: H at edge sites of a graphite layer (formed after ambient dissociative chemisorption of H-2), and a weakly bound layer of mobile H atoms (formed by surface diffusion of H atoms after dissociative chernisorption of H-2 at 500 K). The INS spectra exhibited characteristic riding modes of H on carbon and on Pt or Ru. In these riding modes H atoms move in phase with vibrations of the carbon and metal lattices. The lattice modes are amplified by neutron scattering from the H atoms attached to lattice atoms. Uptake of hydrogen, and spillover, was greater for the Ru containing catalysts than for the Pt/C catalyst. The INS experiments have thus directly demonstrated H spillover to the carbon support of these metal catalysts.