The smectitic minerals in a bentonite deposit from melo (Uruguay)

International audienceA nearly monomineralic 1.5 m thick bentonite bed sampled in Melo (Uruguay) appears to be a pure high-charge montmorillonite: [Si3.94 Al0.06] (Al1.40 Fe 3+ 0.11 Ti0.02 Mg0.49 Mn0.01) O10 (OH)2 Na0.01 K0.08 Ca0.18. However, contrasting swelling behaviors have been evidenced by fitting the experimental X-ray diffraction patterns recorded on oriented preparations of the same sample in different saturation states. According to the expandability of the layers in the Ca-, K- and K-Ca-saturated (that is saturated first with K + and subsequently with Ca2+) states, three "layer types" were defined. Low-, intermediate-, and high-charge layers are fully, partly, and not expandable, respectively, after K-saturation. Collapse of high-charge layers is not reversible after subsequent Ca-saturation, most likely because of tetrahedral substitutions. These three different layer types are segregated in two distinct randomly interstratified mixedlayer phases. TSA and CEC are shown to depend on the interlayer cation composition

Use of Green Sulla Forage for Feeding. 1. Effects on Lamb Growth and Gastrointestinal Nematode Parasite Infestation

Recent studies have shown that some forage legumes containing condensed tannins (CT), such as sulla (Hedysarum coronarium L.), can reduce the gastrointestinal nematode burden in sheep (Niezen et al., 1998) and increase post-ruminal protein availability (Waghorn et al., 1994). This study aimed to evaluate the anthelmintic and nutritional properties of sulla forage in relation to its CT content. Thus, the growth performance and the level of nematode infestation of lambs fed sulla were compared with those of lambs fed ryegrass (Lolium multiflorum Lam. subsp. wersterwoldicum), lacking in CT

Coexistence of halloysite and kaolinite: a study on the genesis of kaolin clays of Campo Alegre Basin, Santa Catarina State, Brazil

Kaolin at Campo Alegre Basin, Santa Catarina State, Brazilwas formed from alteration of volcanic acid rocks. Halloysite clays dominate the clay fraction of the matrix of the kaolin body, whereas a poorly crystalline kaolinite is abundant in veins. Some primary blocky structures have high amounts of illite, in one mine, but in general, only low contents of illite-smectite, illite, chlorite-vermiculite, vermiculite and quartz were identified in the clay fraction of the samples. Toward the top of the mines, hematite and lepidocrocite appear in horizontal red and ochre colored levels and the amount of kaolinite increases compared to halloysite. The vertical zoning of alteration levels, the changes in mineralogy, the positive correlation between depth and Cation Exchange Capacity of the clays, the preservation of different types of rock textures in the kaolin bodies, the dominant tube morphology of the halloysite clays indicate a supergene genesis for the deposits. Criteria to distinguish between supergene and hypogene kaolin are discussed. Transmission Electron Microscopy of the cross sections of halloysite tubes showed polygonal forms that are ascribed to be transitional between kaolinite and halloysite. It is proposed that some of the kaolinite of these deposits be inherited from the dehydration of halloysite tubes

Caracterización de parámetros reproductivos y endocrinos en una población de conejas ibicencas

El conejo ibicenco o conill pagès d’Eivissa es una población originaria de esta isla que actualmente presenta un escaso número de efectivos, ya que está siendo desplazada por otras razas con mayores rendimientos productivos. La conservación de este tipo de poblaciones precisa de la creación de bancos de germoplasma, con lo que es necesario establecer primeramente sus características reproductivas. Por ello, el objetivo del presente trabajo ha sido caracterizar algunos parámetros reproductivos de hembras ibicencas y compararlos con el cruce comercial de California x Neozelandés blanco, que es el habitualmente utilizado en cunicultura para producción. La fertilidad obtenida fue similar en ambos grupos, siendo de un 76,8% y de un 81,3% para las conejas híbridas e ibicencas, respectivamente. La prolificidad, el peso de la camada a 21 días de vida, la producción de leche, el número de gazapos destetados, el peso de la camada al destete y su ganancia media diaria fue superior en los cruces comerciales que en la población ibicenca, presentando ésta última una mayor duración de la gestación y un mayor peso individual al destete. Los ibicencos tardaron un par de días más en alcanzar el peso de sacrificio que los híbridos comerciales, puesto que su ganancia media diaria fue menor y el índice de conversión fue siempre superior, salvo en la última semana que disminuyó y se equiparó al de los híbridos. Respecto a los parámetros endocrinos, tanto las concentraciones de LH como las de progesterona post-ovulación fueron superiores para las hembras híbridas comerciales. finalmente, los datos de caracterización de la respuesta ovárica muestran que las hembras de cruce comercial presentaron un mayor número de folículos preovulatorios y de oocitos por ovario, así como un mayor número de cuerpos lúteos y embriones recuperados, que presentaron además una mayor velocidad de desarrollo embrionario, que las ibicencas. Por tanto, se ha comprobado experimentalmente que el conejo ibicenco, al ser una especie rústica, no seleccionada, presenta características reproductivas menos mejoradas que las de los cruces comerciales, si bien sigue siendo importante su conservación desde el punto de vista del mantenimiento de la biodiversidad genética

Increased glycation and oxidative damage to apolipoprotein B100 of LDL cholesterol in patients with type 2 diabetes and effect of metformin

OBJECTIVE The aim of this study was to investigate whether apolipoprotein B100 of LDL suffers increased damage by glycation, oxidation, and nitration in patients with type 2 diabetes, including patients receiving metformin therapy. RESEARCH DESIGN AND METHODS For this study, 32 type 2 diabetic patients and 21 healthy control subjects were recruited; 13 diabetic patients were receiving metformin therapy (median dose: 1.50 g/day). LDL was isolated from venous plasma by ultracentrifugation, delipidated, digested, and analyzed for protein glycation, oxidation, and nitration adducts by stable isotopic dilution analysis tandem mass spectrometry. RESULTS Advanced glycation end product (AGE) content of apolipoprotein B100 of LDL from type 2 diabetic patients was higher than from healthy subjects: arginine-derived AGE, 15.8 vs. 5.3 mol% (P < 0.001); and lysine-derived AGE, 2.5 vs. 1.5 mol% (P < 0.05). Oxidative damage, mainly methionine sulfoxide residues, was also increased: 2.5 vs. 1.1 molar equivalents (P < 0.001). 3-Nitrotyrosine content was decreased: 0.04 vs. 0.12 mol% (P < 0.05). In diabetic patients receiving metformin therapy, arginine-derived AGE and methionine sulfoxide were lower than in patients not receiving metformin: 19.3 vs. 8.9 mol% (P < 0.01) and 2.9 vs. 1.9 mol% (P < 0.05), respectively; 3-nitrotyrosine content was higher: 0.10 vs. 0.03 mol% (P < 0.05). Fructosyl-lysine residue content correlated positively with fasting plasma glucose. Arginine-derived AGE residue contents were intercorrelated and also correlated positively with methionine sulfoxide. CONCLUSIONS Patients with type 2 diabetes had increased arginine-derived AGEs and oxidative damage in apolipoprotein B100 of LDL. This was lower in patients receiving metformin therapy, which may contribute to decreased oxidative damage, atherogenicity, and cardiovascular disease

Fertilidad, desarrollo embrionaria y prolificidad de conejas nulíparas alimentadas con piensos enriquecidos en ácidos grasos poliinsaturados n-3.

Un total de 105 conejas nulíparas se alimentaron ad libitum un mes antes y durante su primera gestación con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=53) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etéreo y 38% de ácidos grasos poli-insaturados (AG n-3) para la dieta experimental (grupo P; n=52). A los 4,5 meses de edad se determinó la fertilidad después de ser inseminadas artificialmente y tratadas con 20 μg de Gonadorelina (Inducel-GnRH, Ovejero) para inducirles la ovulación. Al parto se determinó la duración de la gestación, el número y peso de los gazapos nacidos vivos y muertos. Se escogieron 16 conejas al azar, 8 de cada grupo, y se realizaron ecografías a los 8, 15 y 22 días de gestación en las que se determinó las dimensiones del embrión y de los anejos fetales. La suplementación con AG n-3 no afectó a los resultados productivos determinados ya que se trata de parámetros que en nulíparas son difíciles de mejorar y suelen ser altos. Tampoco se observaron diferencias en las determinaciones ecográficas pero se han podido definir medidas fisiológicas de los fetos y anejos placentarios de gran utilidad para futuros estudios en esta especie

Fertilidad, desarrollo embrionario y prolificidad de conejas nulíparas alimentadas con piensos enriquecidos en ácidos grasos poliinsaturados n-3

One hundred and five nulliparous rabbit does were fed ad libitum one month before and during pregnancy with two isofibrous, isoenergetic and isoproteic diets supplemented with two different fat sources: 0.75% lard for control diet (C group: n=53) or 1.5% of a supplement (Optomega-50; Optivite International Ltd., España) containing a 50% of ether extract and 38% of n-3 polyunsaturated fatty acids (PUFA) for experimental diet (group P n-3; n=52). Fertility after artificial insemination and induction of ovulation with 20 μg of Gonadorelina (Inducel-GnRH, Ovejero) at 4.5 months of age was assessed. At parturition, pregnancy length and prolificacy (number and weight of born alive and number of stillborn) were observed. A total of 8 pregnant does from each experimental group were chosen at random to study embryo and placenta dimensions by means of ultrasonography at 8, 15 and 22 days of pregnancy. PUFA n-3 supplementation did not affect any productive results due the success on reproductive features of nulliparous does which are difficult to improve. Neither, any differences in ultrasonographic meausrements were obtained; nevertheless we have defined useful physiological parameters of rabbit embryo and placenta to future studies in this specie.Un total de 105 conejas nulíparas se alimentaron ad libitum un mes antes y durante su primera gestación con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=53) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etéreo y 38% de ácidos grasos poli-insaturados (AG n-3) para la dieta experimental (grupo P; n=52). A los 4,5 meses de edad se determinó la fertilidad después de ser inseminadas artificialmente y tratadas con 20 μg de Gonadorelina (Inducel-GnRH, Ovejero) para inducirles la ovulación. Al parto se determinó la duración de la gestación, el número y peso de los gazapos nacidos vivos y muertos. Se escogieron 16 conejas al azar, 8 de cada grupo, y se realizaron ecografías a los 8, 15 y 22 días de gestación en las que se determinó las dimensiones del embrión y de los anejos fetales. La suplementación con AG n-3 no afectó a los resultados productivos determinados ya que se trata de parámetros que en nulíparas son difíciles de mejorar y suelen ser altos. Tampoco se observaron diferencias en las determinaciones ecográficas pero se han podido definir medidas fisiológicas de los fetos y anejos placentarios de gran utilidad para futuros estudios en esta especie

The identification and analysis of making-do waste: insights from two Brazilian construction sites

Making-do has been pointed out as an important category of waste in the construction industry. It refers to a situation in which a task starts or continues without having available all the inputs required for its completion, such as materials, machinery, tools, personnel, external conditions, and information. By contrast, the literature points out that improvisation is a ubiquitous human practice even in highly structured business organizations, and plays an important role when rules and methods fail. The aim of this paper is to provide some insights on the nature of making-do as a type of waste, based on two exploratory case studies carried out on construction sites. The main contributions of this research work are concerned with the identification of different categories of making-do and its main causes. This paper also discusses some strategies for reducing making-do on construction sites