Geomicrobiological characterization of the evaporitic ecosystem in the hypersaline lake Laguna Verde (Andean Puna, Northwestern Argentina).

Laguna Verde's dome-shaped structures are distinctive formations within the Central Andes, displaying unique geomicrobiological features. This study represents a pioneering investigation into these structures, assessing their formation, associated taxa, and ecological significance. Through a multifaceted approach that includes chemical analysis of the water body, multiscale characterization of the domes, and analysis of the associated microorganisms, we reveal the complex interplay between geology and biology in this extreme environment. The lake's alkaline waters that are rich in dissolved cations and anions such as chloride, sodium sulfate, and potassium, coupled with its location at the margin of the Antofalla salt flat, fed by alluvial fans and hydrothermal input, provide favorable conditions for mineral precipitation and support for the microorganism's activity. Laguna Verde's dome-shaped structures are mainly composed of gypsum and halite, displaying an internal heterogeneous mesostructure consisting of three zones: microcrystalline, organic (orange and green layers), and crystalline. The green layer of the organic zone is predominantly composed of Proteobacteria, Bacteroidetes, and Cyanobacteria, while the orange layer is mostly inhabited by Cyanobacteria. The results of the study suggest that oxygenic photosynthesis performed by Cyanobacteria is the main carbon fixation pathway in the microbial community, supported by carbon isotopic ratios of specific biomarkers. This finding highlights the important role played by Cyanobacteria in this ecosystem.

Análisis In vitro de yesos dentales de alta resistencia y baja expansión disponibles en Perú / In vitro analysis of high resistance and low expansion dental plasters available in Peru

Objetivo. Comparar la dureza, estabilidad dimensional y resistencia a la compresión de los yesos dentales de alta resistencia y baja expansión disponibles en el Perú. Métodos. Se realizó un estudio descriptivo, observacional y transversal. Se confeccionaron muestras de forma cilíndrica (8) y rectangular (8), de siete yesos dentales de alta resistencia y baja expansión. Se evaluó la dureza utilizando el Durómetro Universal Identec, la estabilidad dimensional con un calibrador digital y la resistencia a compresión con la Máquina de Ensayo Universal. Para determinar si hay diferencia en cada una de estas propiedades se empleó el análisis de varianza, la prueba F y la prueba de Duncan. Además, se empleó la prueba de comparación de medias, t de Student, para evaluar si difieren con los valores de la ADA (Asociación Dental Americana). Resultados. La dureza, estabilidad dimen-sional y resistencia a la compresión promedio de los yesos dentales presentó diferencias significativas (p<0.05) entre cada uno con los promedios estándares establecidos por la ADA. Conclusiones. En relación resistencia a la compresión el 100% de los yesos analizados cumplen con los parámetros establecidos por la ADA, en relación estabilidad dimensional solo el 28.6% y el 100% no alcanzan los estándares de dureza promedio establecidos por la ADA.

Objective. To compare the hardness, dimensional stability, and compressive strength of high-strength, low-expansion dental plasters available in Peru, according to ADA criteria. Methods. A descriptive, observational and cross-sectional study was developed. A selection of 8 cylindrical-shaped samples and 8 rectangular- shaped ones, from seven high-resistance, low-expansion dental plasters were fabricated. The hardness was evaluated using the Identec Universal Durometer. Dimensional stability was evaluated with a digital caliper and compressive strength was evaluated with the Instron Universal Testing Machine. To determine if there is a difference in each of these properties, the analysis of variance, F test, and the Duncan's test were used. In addition, to assess whether these values differ from those of the ADA, the mean comparison test, student's t table, were used. Results. The hardness, dimensional stability and average compressive strength of the high-strength, low-expansion dental plasters showed that there are significant di-fferences (p<0.05) between each of the dental plasters and with the standard averages established by the American Dental Association. (ADA). Conclusions. 100% of the high-strength, low-expansion dental casts meet the parameters established by the ADA in terms of their compressive strength, only 28.6% of these comply with the ADA in terms of dimensional stability and that 100% of these do not meet the average hardness standards established by the ADA.

Soil amendments to reduce cadmium in cacao (Theobroma cacao L.): A comprehensive field study in Ecuador.

The new EU regulations on maximum levels of cadmium (Cd) in cacao products sparked research on countermeasures to reduce Cd concentrations in cacao beans. This study was set up to test the effects of soil amendments in two established cacao orchards (soil pH 6.6 and 5.1) in Ecuador. Soil amendments included: 1) agricultural limestone at 2.0 and 4.0 Mg ha-1 y-1, 2) gypsum at 2.0 and 4.0 Mg ha-1 y-1 and 3) compost at 12.5 and 25 Mg ha-1 y-1, all amendments were applied at the surface during two subsequent years. Lime application increased the soil pH by one unit down to 20 cm depth. On the acid soil, leaf Cd concentrations decreased by lime application and the reduction factor gradually rose to 1.5 after 30 months. No effects of liming or gypsum on leaf Cd was found in the pH neutral soil. Compost application in the pH neutral soil reduced leaf Cd concentration with factor 1.2 at 22 months but that effect was absent at 30 months after application. Bean Cd concentrations were unaffected by any of the treatments at 22 months after application (acid soil) or 30 months (pH neutral soil) suggesting that any treatment effects on bean Cd might be even more delayed than in leaves. Soil columns experiments in the laboratory showed that mixing lime with compost largely enhanced the depth of lime penetration compared to lime only. Compost + lime reduced 10-3 M CaCl2 extractable Cd in soil without lowering extractable Zn. Our results suggest that soil liming has the potential to lower Cd uptake in cacao in the long term in acid soils and that the compost + lime treatment should be tested at field scale to accelerate the effects of the mitigation.

Soil acidity and soy phytometry under application of limestone and agricultural gypsum / Acidez do solo e fitometria de soja sob aplicação de calcário e gesso agrícola

The soybean is one of the main agricultural crops in Brazil, because the use of its grains is an important source of protein and vegetable oil. One of the main limiting factors for obtaining high yields in soybean in tropical soils is related to the need to correct soil acidity. The objective of this study was to evaluate the growth of (Glycine max (L.) Merrill) and the variation of soil pH values under the application of limestone and agricultural gypsum. The experimental design was completely randomized, distributed in a 4x4 factorial scheme. The treatments consisted of doses of 0, 1.5, 3.0 and 4.5 t ha-1of only limestone, only gypsum and the combination of limestone and gypsum, repeated four times, totaling 64 experimental units. The soil pH was evaluated at 30, 45, 60, 75 days before sowing. The growth variables were: number of pods, shoot dry mass, root dry mass, root length and shoot/root ratio. The variables pH 75 days, root length and shoot/root ratio were significantly influenced by the treatments, alone or in interaction. For pH 30, pH 45 and pH 60 days, number of pods and shoot dry mass, there were isolated effects of treatments for gypsum and limestone. In root dry mass, the effect of the treatment was verified only with the use of limestone. As a conclusion, the application of limestone and gypsum reduces the soil acidity, obtaining higher pH values from the doses of 3000 kg ha-1, with the combination of limestone and gypsum. The use of gypsum consortium with limestone promotes significant results in the growth of soybean plants.

A soja é uma das principais culturas agrícolas do Brasil, pois, a utilização de seus grãos é uma importante fonte de proteínas e óleo vegetal. Um dos principais fatores limitantes para obtenção de altos rendimentos na soja, em solos tropicais, está relacionado à necessidade de correção da acidez do solo. O objetivo do estudo foi avaliar o crescimento de (Glycine max (L.) Merrill) e a variação dos valores de pH do solo sob a aplicação de calcário e gesso agrícola. O delineamento experimental utilizado foi inteiramente casualizado, distribuídos em esquema fatorial 4x4, os tratamentos constaram de doses 0, 1,5, 3,0 e 4,5 t ha-1sendo elas somente calcário, somente o gesso e a combinação de calcário e gesso, repetidos quatro vezes, totalizando 64 unidades experimentais. O pH do solo foi avaliado a 30, 45, 60 e 75 dias antes da semeadura. As variáveis de crescimento foram: número de vagens, massa seca da parte aérea, massa seca da raiz, comprimento da raiz e relação parte aérea/raiz. As variáveis pH 75 dias, comprimento da raiz e relação parte aérea/raiz, foram influenciadas significativamente pelos tratamentos, isoladamente ou em interação. Para o pH 30, 45 e 60 dias, número de vagens e massa seca da parte aérea ocorreram efeitos isolados dos tratamentos para gesso e calcário. Na massa seca da raiz o efeito do tratamento foi verificado apenas com a utilização do calcário. Como conclusão, a aplicação de calcário e gesso reduz a acidez do solo, obtendo maiores valores de pH a partir das doses de 3000 kg ha-1, com a combinação de calcário e gesso. A utilização do gesso consorciado com o calcário promove resultados significativos no crescimento das plantas de soja.

The Lepidoptera of Cuatrociénegas Protected Area 1. A new species in the genus Callistege Hübner, [1823] (Erebidae, Erebinae, Euclidiini) from the Chihuahuan Desert, Coahuila, Mexico.

A new species of Callistege Hübner, [1823] (Lepidoptera, Erebidae, Erebinae, Euclidiini) is described from Cuatrociénegas Protected Area and Biosphere Preserve in Coahuila, Mexico. Adult male and female moths are illustrated, including genitalia. Callistege clara Homziak & Metzler, sp. nov. is one of 27 new species of insects discovered during an inventory survey of arthropods of White Sands National Monument, USA, and Cuatrociénegas Protected Area (Mexico), funded by the U.S. National Park Service. The Cuatrociénegas Basin is known for high endemism of aquatic and wetland biota within the Chihuahuan Desert. Callistege clara Homziak & Metzler, sp. nov. was found in a wetland environment.

Preconsolidation stress of gibbsitic and kaolinitic Oxisols under a multipractice conservationist coffee system / Pressão de pré-consolidação de Latossolos gibbsítico e caulinítico sob sistema de multipraticas conservacionista no cultivo cafeeiro

Our goal was to analyze the impact of a multipractice soil conservationist system on coffee production in tropical soils (LATOSSOLO VERMELHO-AMARELO caulinítico/kaolinitic Haplustox and LATOSSOLO VERMELHO-gibbsítico/gibbsitic Acrustox) in Minas Gerais, Brazil. In the experimental area, the soil management involved a set of multiple conservationist practices during cultivation for more than 3.5 yrs. Soil samples were collected at 0-5, 10-15, and 20-25 cm depths at two positions: planting rows and between rows. The soil physical and mechanical properties were determined, with a focus mainly on the preconsolidation stress model (preconsolidation stress versus matric tension). For the purpose of analysis, a split-split plot experimental design was implemented. A linear mixed regression model (LMR) was fitted, and Wald's test was performed (P < 0.05). An improvement of soil physical quality for both Oxisols was observed at the planting row position. The effects of multipractice soil management after 3.5 yrs of cultivation in association with increased gibbsite content could promote new soil structure organization, as revealed by LMR, resulting in more resilient soils (between rows) and increasing the resistance to external pressures on gibbsitic Acrustox. Overall, the findings herein are in concordance with global trends towards conservationist practices that may alleviate soil compaction in agricultural systems to maintain environmental sustainability.(AU)

Nosso objetivo foi analisar o impacto de um sistema de manejo do solo com multi-práticas conservacionistas para o cultivo cafeeiro em solos tropicais (LATOSSOLO VERMELHO-AMARELO caulinítico/ kaolinitic Haplustox and LATOSSOLO VERMELHO gibbsítico/ gibbsitic Acrustox) em Minas Gerais, Brasil. Na área experimental, o manejo do solo incluiu um conjunto de multi-práticas conservacionistas por mais de 3,5 anos. Amostras de solo foram coletadas em 0-5; 10-15; e profundidades de 20 a 25 cm em duas posições: linha e entrelinha. As propriedades físicas e mecânicas do solo foram determinadas, concentrando-se principalmente na modelagem da compactação (estresse de pré-consolidação versus tensão matricial). Para fins de análise, foi considerado o delineamento experimental de parcelas subsubdivididas. Foi ajustado o modelo de regressão linear mista (RLM), bem como o teste F de Wald (P < 0,05). Melhorias na qualidade física do solo em ambos os Latossolos foi observada na linha de plantio. Os efeitos do sistema de manejo multipráticas usado após 3,5 anos de cultivo associado ao maior conteúdo de gibbsita podem promover uma nova organização da estrutura do solo revelada pelo RLM, que resulta em solos mais resilientes (na entrelinha), melhorando a resistência às pressões externas aplicadas ao Latossolo gibbsítico. No geral, os resultados aqui apresentadas estão de acordo com as tendências globais em direção a práticas conservacionistas que podem aliviar a compactação do solo em sistemas agrícolas e manter a sustentabilidade ambiental.(AU)

Evaluating the effect of different combination of impression and pouring materials on marginal and internal adaptation of zirconia crowns / Evaluación del efecto de diferentes combinaciones de materiales de impresión y vertido en la adaptación marginal e interna de las coronas de circonio

Purpose: Two important factors in dental prosthesis are making an accurate impression and producing a suitable cast which represents the exact relationship between prepared tooth and oral structures. This study, aimed to investigate the effects of different combinations of impression and pouring materials on marginal and internal adaptation of premolar zirconia crowns. Material and Methods: Forty maxillary premolars were prepared considering round shoulder finish line. The impressions were made either by additional (Panasil) or condensation (Speedex) silicon, and poured by two different types of gypsum materials (Siladent or GC gypsum) (N=10). Zirconia crowns were fabricated using a CAD-CAM system. The crowns were cemented, and the samples were cut in bucco-lingual direction. Marginal and internal gaps were measured by stereomicroscope (×25). Results: The mean marginal gaps for Pansil-Siladent, Panasil-GC, Speedex-Siladent, and Speedex-GC were 141 µm, 143 µm, 131 µm, and 137 µm respectively. The internal gaps were 334 µm, 292 µm, 278 µm, and 257 µm respectively. The independent T-Student test showed no significant differences in average marginal or internal gap among various impression and gypsum materials or their interactions (p>0.05). Two-way ANOVA test showed no significant differences in maximum marginal or internal gap among various impression and gypsum materials and their interactions (p>0.05). Conclusion: The present study revealed no statistically significant difference in marginal/internal gap among crowns prepared using different combinations of impression-pouring materials evaluated.

Introducción: Dos factores importantes en la prótesis dental son hacer una impresión precisa y la producción de un modelo adecuado que represente la relación exacta entre el diente preparado y las estructuras orales. Este estudio, tuvo como objetivo investigar los efectos de diferentes combinaciones de materiales de impresión y vertido sobre la adaptación marginal e interna de coronas de zirconio premolar. Material y Métodos: Se prepararon cuarenta premolares maxilares considerando la línea de meta del hombro redondo. Las impresiones se realizaron con silicio adicional (Panasil) o de condensación (Speedex) y se vertieron con dos tipos diferentes de materiales de yeso (yeso Siladent o GC) (N = 10). Las coronas de zirconio se fabricaron utilizando el sistema CAD-CAM. Las coronas se cementaron y las muestras se cortaron en dirección buco-lingual. La brecha marginal e interna se midió con estereomicroscopio (×25). Resultados: Las brechas marginales medias para Pansil-Siladent, Panasil-GC, Speedex-Siladent y Speedex-GC fueron de 141µm, 143µm, 131µm y 137µm, respectivamente. Las brechas internas fueron 334µm, 292µm, 278µm y 257µm, respectivamente. La prueba de T-Student independiente no mostró diferencias significativas en la brecha marginal o interna promedio entre varios materiales de impresión y yeso o sus interacciones (p>0.05). La prueba ANOVA bidireccional no mostró diferencias significativas en el espacio marginal o interno máximo entre varios materiales de yeso y de impresión y sus interacciones (p>0.05). Conclusión: El presente estudio no reveló diferencias estadísticamente significativas en la brecha marginal/interna entre las coronas preparadas con diferentes combinaciones de materiales de impresión y vertido evaluados.

Changes in chemical soil and corn yield after application of gypsum and potassium doses / Mudanças no solo químico e na produtividade do milho após a aplicação de doses de gesso e potássio

Soil liming is a common practice in agriculture. It aims to reduce soil acidity and to supply calcium and magnesium. Lime, however, is not easily soluble in the soil, and its reaction products are often concentrated in the application zone, which is mainly the topsoil layer. In order to increase the concentration of nutrients in deeper layers, agricultural gypsum­a byproduct of phosphoric acid production process, rich in calcium and sulfur­is used. In this context, the objective of this study was to evaluate the chemical attributes of the oxysoil and the corn ́s yield to the application of gypsum associated with potassium (K) rates. The study was developed in Uberaba city, Minas Gerais state, Brazil. The factorial scheme was used 5x5, with five rates of K (0, 100, 180, 240, 360 kg ha-1 K2O) and five gypsum rates (0, 500, 1000, 2000, 4000 kg ha-1) in a randomized complete block design with four replications. The soil chemical attributes were evaluated at 0.0-0.20 m and 0.20-0.40 m depth and the biometric and productive attributes of corn. The application of gypsum resulted in the increase of calcium (Ca) and sulfur (S) contents in all depths; reduced the levels of pH, manganese, potential acidity (H + Al) in the 0.0-0.20 m depth, and increase the levels of base of saturation and sum of bases on the 0.20-0.40 m depth. Corn yield and biometric attributes no were influenced by the factors evaluated.

A calagem é uma prática comum na agricultura. Esta prática visa reduzir a acidez do solo, além de fornecer cálcio e magnésio. Contudo, devido ao fato de o calcário apresentar baixa solubilidade no solo, os produtos de sua reação ficam retidos na camada onde o produto foi aplicado, a qual geralmente é na camada superficial do solo. Para se aumentar a concentração de nutrientes em camadas mais profundas, o gesso agrícola - um subproduto da produção de ácido fosfórico, rico em cálcio e enxofre tem sido usado. Neste contexto, o objetivo deste trabalho foi avaliar a influência da aplicação de diferentes doses de gesso em associação a doses de potássio, nos atributos químicos do solo e na produtividade de grãos de milho. O estudo foi conduzido no Instituto Federal de Educação, Ciência e Tecnologia do Triângulo Mineiro (IFTM), Campus Uberaba, localizado no município de Uberaba-MG, Brasil. O experimento foi instalado em esquema fatorial 5x5, sendo cinco doses de gesso (0, 500, 1000, 2000 e 4000 kg ha-1) e cinco doses de K2O (0, 100, 180, 240 e 360 kg ha-1) no delineamento em blocos completos casualizados, com quatro repetições. Os atributos químicos do solo foram avaliados nas camadas de 0,0 a 0,20 m e de 0,20 a 0,40 m, além das características biométricas e produtivas da cultura do milho. A aplicação de gesso resultou no aumento de cálcio e enxofre em ambas as profundidades; reduziu os níveis de pH, manganês, acidez potencial (H + Al) na camada de 0,0-0,20m; e, aumentou os níveis de saturação por bases e soma de bases na camada de 0,20-0,40 m. A produção de milho não foi influenciada pelos fatores avaliados.

Soil biomass and microbial activity in soybean crop area under different cover crops and different soil correction systems / Biomassa e atividade microbiana do solo em área de cultivo de soja sob diferentes plantas de cobertura e diferentes sistemas de correção de solo

This study aimed to evaluate soil biomass and microbial activity and soybean yield under different limestone and gypsum doses and different cover crops. The experiment was carried out in the experimental area of the Fundação de Apoio a Pesquisa Agropecuária de Chapadão, on a Dystrophic Red Latosol, using cultivar Desafio. The experiment consisted of a randomized blocks design, in a split-plot factorial scheme (3x4x3), with three replications. Plots consisted of three gypsum doses: control (without gypsum), recommended dose (2.3 Mg ha-1), and double dose (4.6 Mg ha-1). Subplots consisted of four limestone doses (2, 4, and 6 Mg ha-1) and the control (without limestone). Each block had three different cover crops: Brachiaria, Millet, and allow. The values obtained with the test revealed that brachiaria had better basal respiration in the absence of gypsum. Conversely, millet had better basal respiration in with the gypsum dose. Basal respiration, using brachiaria as cover crop, was higher at the dose of 2700 kg ha-1 of limestone. However, for the fallow and the millet, basal respiration was higher when using the highest limestone dose of 6000 kg ha-1. The variable microbial biomass showed differences between cover crops only in the absence of gypsum. Brachiaria and fallow presented the highest mean for microbial biomass. The use of millet as a cover crop together with gypsum doses increased the microbial biomass. The variables mass of 100 grains and grain yield had higher mean at the limestone dose of 6000 kg ha-1 .

O objetivo do trabalho foi avaliar a biomassa e atividade microbiana do solo, e produtividade da soja sob efeito das diferentes doses de calcário e gesso e diferentes coberturas de solo. O experimento foi conduzido na área experimental da Fundação de Apoio a Pesquisa Agropecuária de Chapadão, sob Latossolo Vermelho Distrófico, com a cultivar Desafio. O delineamento experimental utilizado foi em blocos casualizados, em esquema fatorial (3x4x3) de parcelas subdividas, com 3 repetições. As parcelas foram constituídas por 3 quantidades de gesso agrícola, sendo: controle (sem gesso), recomendado (2,3 Mg ha-1) e o dobro (4,6 Mg ha-1), as subparcelas por 4 doses de calcário (2, 4 e 6 Mg ha-1), além do controle (sem calcário), onde cada bloco apresentou 3 coberturas diferentes: Braquiaria, Milheto e Pousio. Os resultados foram submetidos ao teste de Tukey 5%. Com os valores obtidos pudemos observar que a respiração basal foi melhor para braquiária na ausência de gesso, e na presença o milheto se saiu melhor. A respiração basal, utilizando a braquiária como cobertura, foi maior na dose de 2700 kg ha-1 de calcário. Já utilizando o pousio e o milheto foi na maior dose 6000 kg ha-1. A variável biomassa microbiana apresentou diferença entre as coberturas apenas na ausência de gesso, onde a braquiária e o pousio apresentaram as maiores médias para esta variável. A utilização do milheto como cobertura em conjunto com as doses de gesso acarretou aumento da biomassa microbiana. A massa de 100 grãos e a produtividade de grãos apresentaram maior média na dose de 6000 kg ha-1 de calcário.

Effect of Gypsum on the Early Hydration of Cubic and Na-Doped Orthorhombic Tricalcium Aluminate.

The tricalcium aluminate (C3A) and sulfate content in cement influence the hydration chemistry, setting time and rheology of cement paste, mortar and concrete. Here, in situ experiments are performed to better understand the effect of gypsum on the early hydration of cubic (cub-)C3A and Na-doped orthorhombic (orth-)C3A. The isothermal calorimetry data show that the solid-phase assemblage produced by the hydration of C3A is greatly modified as a function of its crystal structure type and gypsum content, the latter of which induces non-linear changes in the heat release rate. These data are consistent with the in situ X-ray diffraction results, which show that a higher gypsum content accelerates the consumption of orth-C3A and the subsequent precipitation of ettringite, which is contrary to the cub-C3A system where gypsum retarded the hydration rate. These in situ results provide new insight into the relationship between the chemistry and early-age properties of cub- and orth-C3A hydration and corroborate the reported ex situ findings of these systems.

Effect of the mixing method on the dimensional stability of dental stones / Efeito do método de mistura na estabilidade dimensional de gessos odontológicos

Objective: The aim of this study was to evaluate the influence of mixing method and the empiric water/powder ratio on the dimensional change of two types of dental stones (type III and type IV) at different setting times: baseline, loss of brightness, initial and final setting (1/4 and 1pound Gilmore´s needle, respectively) and, after 48 hours at 37°C. Material and Methods: Five mixing methods were used: Gc ­ manufacturer´s recommendation, G1 ­ weighed powder/ empiric water volume and powder on water, G2 - weighed powder/ empiric water volume and water on powder, G3 ­ empiric powder volume, graduated water and powder on water, G4 - empiric powder volume, graduated water and water on powder. The linear expansion was measured according to ISO 6873. The expansion values (x10-2mm) were analyzed by Two-way ANOVA and Tukey HSD test (α=0.05). Results: For type III, the results showed significance for both factors and for interaction; for type IV, only the time were significant ( p<0.05). Limited by methodology, it could be concluded that both dental stones expanded more than the recommended by ISO. Conclusion: The expansion of type III was dependent on the mixing method, and once correct consistency is reached with type IV, there is no influence of mixing method on dimensional stability. (AU)

Objetivo: O objetivo deste estudo foi avaliar a influência do método de mistura e da relação empírica de água/pó na alteração dimensional de dois tipos de gessos odontológicos (tipo III e tipo IV) em diferentes tempos de trabalho: baseline, perda de brilho, inicial e final (agulha de Gilmore de 1/4 e 1 libra, respectivamente) e, após 48 horas a 37 ° C. Material e Métodos: Cinco métodos de mistura foram utilizados: Gc - recomendação do fabricante, G1 - pó pesado / volume empírico de água e pó na água, G2 - pó pesado / volume empírico de água e água no pó, G3 - volume empírico de pó, água graduada e pó na água, G4 - volume de pó empírico, água graduada e água no pó. A expansão linear foi medida de acordo com a norma ISO 6873 (1998). Os valores de expansão (x10-2mm) foram analisados pelo teste ANOVA dois fatores e teste de Tukey HSD (α = 0,05). Resultados: Para o tipo III, os resultados mostraram significância para ambos os fatores e para interação; para o tipo IV, apenas o tempo foi significativo (p < 0,05). Limitado pela metodologia, pode-se concluir que ambos os gessos odontológicos expandiram mais do que o recomendado pela ISO. Conclusão: A expansão do tipo III foi dependente do método de mistura e, uma vez atingida a consistência correta com o tipo IV, não há influência do método de mistura na estabilidade dimensional. (AU)

Arsenic contamination in irrigation water, agricultural soil and maize crop from an abandoned smelter site in Matehuala, Mexico.

Mobility of Arsenic (As) from metallurgical wastes in Matehuala, Mexico has been accounted for ultra-high concentration of As in water (4.8-158mg/L) that is used for recreational purposes as well as cultivation of maize. In this study, we (i) measured As concentrations in soils irrigated with this water, (ii) investigated the geochemical controls of available As, and (iii) measured bioaccumulation of As in maize. Water, soil, and maize plant samples were collected from 3 different plots to determine As in environmental matrices as well as water soluble As in soils. Soil mineralogy was determined by X-ray diffraction analysis. Bioaccumulation of As in maize plants was estimated from the bioconcentration and translocation factors. We recorded As built-up in agricultural soils to the extent of 172mg/kg, and noted that this As is highly soluble in water (30% on average). Maize crops presented high bioaccumulation, up to 2.5 times of bioconcentration and 45% of translocation. Furthermore, we found that water extractable As was higher in soils rich in calcite, while it was lower in soils containing high levels of gypsum, but As bioconcentration showed opposite trend. Results from this study show that irrigation with As rich water represents a significant risk to the population consuming contaminated crops.

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 9. A new species of Givira Walker (Cossidae, Hypoptinae) dedicated to Delinda Mix, including a list of species of Cossidae recorded from the Monument.

The U.S. National Park Service initiated a 10-year study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico in late 2006. Givira delindaesp. n., discovered in 2007 during the first year of study, is described here. The male and female adult moths and genitalia are illustrated. The name is dedicated to Delinda Mix, mother of Steve Mix. The species of Cossidae recorded from the Monument during the study are listed.

Chemical properties of an Oxisol after gypsum application / Extrato de saturação e condutividade elétrica de um Latossolo vermelho eutroférrico após a gessagem

Gypsum utilization is a critical practice in agriculture because of the high solubility and consequent relative neutralization of subsurface toxic aluminum. However, it has been observed that in most cases, gypsum is being randomly utilized without scientifically established parameters or even the need to use it as a soil amendment at all. The objective of this study was to evaluate the chemical composition and electrical conductivity of an Oxisols saturation extract under different gypsum doses (0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1). This experiment was conducted in a greenhouse environment. Soil columns (V = 1.57 dm3) were filled with sifted (2 mm) soil collected from the upper layer (0-20 cm). The experimental design adopted was completely randomized with five repetitions. The treatments consisted of a 5 × 2 factorial through five gypsum doses (0.0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1 of gypsum consisting of 224.1 g kg-1 S, 314.8 g kg-1 CaO, and 7 g kg-1 P2O5) and two depth evaluations (0-10 and 10-20 cm). After the treatments, soil from both 0-10 cm and 10-20 cm layers was removed from the columns, sifted once (2 mm), and subjected to vacuum extraction to assess the saturation extract. The data acquired was processed and submitted to variance analysis (when due) and adjusted to regression equations when statistically relevant. Significant increases were observed for Ca, Mg, K, P, and S, although Al, Si, and pH presented no statistically significant difference. The electrical conductivity value of this soil in particular is directly related to the gypsum dose.

A aplicação do gesso agrícola é importante na agricultura por sua alta solubilidade e consequente neutralização relativa do alumínio tóxico na camada superficial do solo. Entretanto, tem-se observado a ocorrência de aplicações com base em critérios aleatórios, sem embasamento científico coerente com a experimentação agrícola. O objetivo desse estudo foi avaliar a composição química e condutividade elétrica do extrato de saturação de um Latossolo Vermelho eutroférrico sob diferentes doses de gesso (0; 1,0; 2,0; 4,0 Mg ha-1). O experimento foi conduzido em ambiente de casa de vegetação. Colunas de solo (V = 1,57 dm3) foram preenchidos com solo peneirado (2 mm) coletado na camada superficial (0-20 cm). O delineamento experimental utilizado foi inteiramente casualizado, com cinco repetições. Os tratamentos testados resultaram de um fatorial 5 x 2 em que os fatores foram cinco doses de gesso (0,0 1,0 2,0 4,0 e 8,0 Mg ha-1 de gesso agrícola (224,1 g kg-1 de S, 314,8 g kg-1 de CaO e 7 g kg-1 de P2O5) e 2 profundidades de amostragem (0-10 e 10-20 cm). Após os tratamentos, ambas as camadas de solo (0-10 cm e 10-20 cm) foram removidas das colunas, peneiradas (2 mm) e submetidas a extração à vácuo para obtenção do extrato de saturação. Os dados obtidos foram submetidos a análises de variância e ajustados às equações de regressão, quando diferiram estatisticamente. Enquanto os teores de Al, Si, e o pH do extrato de saturação do solo não foram influenciados, os teores de Ca, Mg, K, P e S aumentam em função da aplicação superficial de doses de gesso agrícola. Após a aplicação de diferentes doses de gesso agrícola, não ocorreram variações significativas nos teores de P, Si, Al e do pH da camada subsuperficial (10-20) do solo. A condutividade elétrica (CE) do extrato de saturação do solo estudado aumentou com o aumento das doses de gesso.

Chemical properties of an Oxisol after gypsum application / Extrato de saturação e condutividade elétrica de um Latossolo vermelho eutroférrico após a gessagem

Gypsum utilization is a critical practice in agriculture because of the high solubility and consequent relative neutralization of subsurface toxic aluminum. However, it has been observed that in most cases, gypsum is being randomly utilized without scientifically established parameters or even the need to use it as a soil amendment at all. The objective of this study was to evaluate the chemical composition and electrical conductivity of an Oxisols saturation extract under different gypsum doses (0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1). This experiment was conducted in a greenhouse environment. Soil columns (V = 1.57 dm3) were filled with sifted (2 mm) soil collected from the upper layer (0-20 cm). The experimental design adopted was completely randomized with five repetitions. The treatments consisted of a 5 × 2 factorial through five gypsum doses (0.0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1 of gypsum consisting of 224.1 g kg-1 S, 314.8 g kg-1 CaO, and 7 g kg-1 P2O5) and two depth evaluations (0-10 and 10-20 cm). After the treatments, soil from both 0-10 cm and 10-20 cm layers was removed from the columns, sifted once (2 mm), and subjected to vacuum extraction to assess the saturation extract. The data acquired was processed and submitted to variance analysis (when due) and adjusted to regression equations when statistically relevant. Significant increases were observed for Ca, Mg, K, P, and S, although Al, Si, and pH presented no statistically significant difference. The electrical conductivity value of this soil in particular is directly related to the gypsum dose.(AU)

A aplicação do gesso agrícola é importante na agricultura por sua alta solubilidade e consequente neutralização relativa do alumínio tóxico na camada superficial do solo. Entretanto, tem-se observado a ocorrência de aplicações com base em critérios aleatórios, sem embasamento científico coerente com a experimentação agrícola. O objetivo desse estudo foi avaliar a composição química e condutividade elétrica do extrato de saturação de um Latossolo Vermelho eutroférrico sob diferentes doses de gesso (0; 1,0; 2,0; 4,0 Mg ha-1). O experimento foi conduzido em ambiente de casa de vegetação. Colunas de solo (V = 1,57 dm3) foram preenchidos com solo peneirado (2 mm) coletado na camada superficial (0-20 cm). O delineamento experimental utilizado foi inteiramente casualizado, com cinco repetições. Os tratamentos testados resultaram de um fatorial 5 x 2 em que os fatores foram cinco doses de gesso (0,0 1,0 2,0 4,0 e 8,0 Mg ha-1 de gesso agrícola (224,1 g kg-1 de S, 314,8 g kg-1 de CaO e 7 g kg-1 de P2O5) e 2 profundidades de amostragem (0-10 e 10-20 cm). Após os tratamentos, ambas as camadas de solo (0-10 cm e 10-20 cm) foram removidas das colunas, peneiradas (2 mm) e submetidas a extração à vácuo para obtenção do extrato de saturação. Os dados obtidos foram submetidos a análises de variância e ajustados às equações de regressão, quando diferiram estatisticamente. Enquanto os teores de Al, Si, e o pH do extrato de saturação do solo não foram influenciados, os teores de Ca, Mg, K, P e S aumentam em função da aplicação superficial de doses de gesso agrícola. Após a aplicação de diferentes doses de gesso agrícola, não ocorreram variações significativas nos teores de P, Si, Al e do pH da camada subsuperficial (10-20) do solo. A condutividade elétrica (CE) do extrato de saturação do solo estudado aumentou com o aumento das doses de gesso.(AU)

Evaluación de una resina epóxica experimental como material alternativo para obtención de modelos odontológicos / Evaluation of an experimental epoxy resin as an alternative material for dental casts

El objetivo de este estudio fue comparar la fidelidad de copia y estabilidad dimensional entre modelos de resina epóxica y modelos de yeso (Fuji Rock EP - GC Europe; Implant Stone - Polidental). Fue realizada la impresión de una matriz de acero para obtener 30 especímenes (n=10). La matriz simulaba dos piezas dentarias talladas para recibir coronas totales, sobre éstas fueron adaptados dos copings metálicos con aletas horizontales. Se evaluó al microscopio (Microscopio Measurescope, Nikon) la distancia entre el coping y la línea de terminación de las piezas talladas (en adelante, "desadaptación vertical") y la distancia entre las aletas horizontales de los copings (en adelante, "desadaptación horizontal"), las medidas obtenidas entre la matriz de acero y copings metálicos fueron consideradas como grupo control. Los copings metálicos fueron después adaptados sobre los modelos de yeso y sobre la resina experimental y fue realizada la evaluación al microscopio del mismo modo que el descrito anteriormente. Fueron realizadas 3 mediciones en dos tiempos (24 y 48 horas). Respecto a la desadaptación horizontal, el yeso FujiRock presentó una mejor estabilidad dimensional después de 24 horas, ya que la desadaptación fue similar estadísticamente a la desadaptación de la matriz (control) (p>0,05). Después de 48 horas, todos los grupos presentaron valores similares a la matriz (p>0,05). Respecto a la desadaptación vertical, todos los materiales presentaron diferencia estadísticamente significante en relación a la matriz (p?0,05), sin embargo, no hubo diferencia entre los materiales evaluados (p>0,05). La resina epóxica experimental puede ser una alternativa viable para la obtención de modelos odontológicos...

The aim of this study was to compare the accuracy of surface detail reproduction and dimensional stability of casts made from an experimental epoxy resin and gypsum (Fuji Rock EP - GC Europe; Implant Stone - Polidental). A steel matrix was molded to obtain 30 cast samples (n=10). The matrix simulated two teeth prepared to receive total crowns on which two metal copings with horizontal flaps were adapted. Three readings were performed (Measurescope microscope, Nikon) in order to measure the vertical and horizontal misfit and those readings were used as control. Metal copings were adapted over the gypsum and epoxy resin casts and three measurements were made in two periods (24 and 48 hours). Regarding the horizontal misfit, Fujirock had better dimensional stability after 24 hours, being statistically similar to the matrix (p> 0.05). After 48 hours, all groups had statistically similar values to the matrix (p> 0.05). Regarding the vertical misfit, all materials were statistically different in relation to the matrix (p ? 0.05). However, there was no statistically significant difference between the materials evaluated (p> 0.05). The experimental epoxy resin could be a suitable alternative to obtain dental casts...

Mecanismo de tolerância interna das plantas ao alumínio / Internal mechanism of tolerance to the aluminum on the plants

A ocorrência de alumínio (Al) em concentrações tóxicas no solo é considerada como a principal causa da baixa fertilidade dos solos do cerrado no Brasil, visto que o Al é um constituinte das partículas de argila do solo. O efeito negativo da acidez do solo e da toxidez por Al na produção agrícola tem sido menos frequente em sistema de plantio direto, com ausência de resposta das culturas tanto à calagem quanto a gessagem, fato relacionado à complexação de Al pelos ácidos orgânicos. Os mecanismos de tolerância internos são aqueles em que o Al entra no simplasto e a tolerância é encontrada pela formação de quelatos no citossol, compartimentalização no vacúolo, ligação do alumínio a proteínas e atuação de enzimas tolerantes ao Al. A tolerância ao Al é geneticamente controlada e as espécies de plantas diferem significativamente quanto ao grau dessa tolerância. Devido à complexidade da fitotoxicidade do Al e dos mecanismos de tolerância apresentados pelas plantas há necessidade de investigação científica mais aprofundada para a obtenção de cultivares tolerantes, com o intuito de elevar a produtividade dos solos com presença de Al.

The occurrence of toxic Al concentrations in the soil is considered the main cause of low fertility of cerrado soils in Brazil, since as the Al is a component of soil clay particules. The negative effect of soil acidity and Al toxicity in agricultural production has been less common in no tillage, and observed the lack of crop response to liming as much as the gypsum, being related to complexation of Al with organic acids. The internal tolerance mechanisms are those in which Al enters the symplast and tolerance is found for the formation of chelates in the cytosol, compartmentalization in the vacuole, aluminum bound to proteins and evolution of Al-tolerant enzymes. The tolerance to Al is genetically controlled and plant species differ significantly in the degree of tolerance. Due to the complexity of Al phytotoxicity and tolerance mechanisms displayed by plants, further scientific research is desired for obtaining tolerant cultivars to raise the productivity of soils with Al.

Mecanismo de tolerância interna das plantas ao alumínio / Internal mechanism of tolerance to the aluminum on the plants

A ocorrência de alumínio (Al) em concentrações tóxicas no solo é considerada como a principal causa da baixa fertilidade dos solos do cerrado no Brasil, visto que o Al é um constituinte das partículas de argila do solo. O efeito negativo da acidez do solo e da toxidez por Al na produção agrícola tem sido menos frequente em sistema de plantio direto, com ausência de resposta das culturas tanto à calagem quanto a gessagem, fato relacionado à complexação de Al pelos ácidos orgânicos. Os mecanismos de tolerância internos são aqueles em que o Al entra no simplasto e a tolerância é encontrada pela formação de quelatos no citossol, compartimentalização no vacúolo, ligação do alumínio a proteínas e atuação de enzimas tolerantes ao Al. A tolerância ao Al é geneticamente controlada e as espécies de plantas diferem significativamente quanto ao grau dessa tolerância. Devido à complexidade da fitotoxicidade do Al e dos mecanismos de tolerância apresentados pelas plantas há necessidade de investigação científica mais aprofundada para a obtenção de cultivares tolerantes, com o intuito de elevar a produtividade dos solos com presença de Al.(AU)

The occurrence of toxic Al concentrations in the soil is considered the main cause of low fertility of cerrado soils in Brazil, since as the Al is a component of soil clay particules. The negative effect of soil acidity and Al toxicity in agricultural production has been less common in no tillage, and observed the lack of crop response to liming as much as the gypsum, being related to complexation of Al with organic acids. The internal tolerance mechanisms are those in which Al enters the symplast and tolerance is found for the formation of chelates in the cytosol, compartmentalization in the vacuole, aluminum bound to proteins and evolution of Al-tolerant enzymes. The tolerance to Al is genetically controlled and plant species differ significantly in the degree of tolerance. Due to the complexity of Al phytotoxicity and tolerance mechanisms displayed by plants, further scientific research is desired for obtaining tolerant cultivars to raise the productivity of soils with Al.(AU)

Produção, estado nutricional e qualidade da alfafa sob pastejo e ocorrência de plantas daninhas em resposta à calagem, gessagem e adubação potássica / Yield, nutritional status and quality of alfafa under grazing and weed occurence in response to liming, gypsum and potassium fertilization

A alfafa é uma planta extremamente exigente em fertilidade, e os desbalanços na correção do solo e adubação podem levar a perda de vigor do alfafal, originando o desenvolvimento agressivo de plantas daninhas. O objetivo deste trabalho foi avaliar o efeito da aplicação no solo de calcário, gesso e potássio na produção de massa de matéria seca, estado nutricional, qualidade da alfafa e na ocorrência de plantas daninhas. Os resultados indicaram que as práticas da calagem, associada à gessagem e as adubações com potássio podem contribuir decisivamente no aumento da longevidade do alfafal. As maiores repostas da alfafa à adubação potássica ocorreram na maior saturação por bases (V = 80%) do solo. Foi também observada a tendência de diminuição da ocorrência de plantas daninhas com a melhora da fertilidade do solo. A qualidade nutricional da forrageira não foi afetada pelos tratamentos.(AU)

Alfalfa is extremely demanding in fertility, calcium and fertilizer unbalance of soil can lead to loss of alfalfa vigor, causing the development of aggressive weeds. The aim of this study was to evaluate the effect of soil amendment with lime and gypsum and potassium fertilizer on the alfalfa dry matter production, nutritional status and quality and weed occurrence. The results indicated that the practices associated with the lime and gypsum and fertilization with potassium can contribute substantially to the increased longevity of alfalfa. The major responses of alfalfa to potassium fertilization occurred in the highest soil base saturation (V = 80%). A trend of decreasing the occurrence of weeds with the improvement of soil fertility was also observed. The forage nutritional quality was not affected by treatments.(AU)

Soil chemical atributtes on brachiaria spp in integrated crop livestock system / Características químicas do solo em pastagens de Brachiaria em sistema integrado lavoura-pecuária

Integrated crop-livestock systems have attracted more interest in the last few years due to their capacity of improving stability and sustainability of agricultural systems when compared to more specialized production ones. The crop-livestock integration is an effective technique, but complex to maintain pasture productivity and its recovery, whose efficiency depends on soil physical management and its chemical fertility. Regarding the soil fertility, the corrective practices generally begin with the liming due to the high acidity of most Brazilian soils and low levels of Ca and Mg in the exchange complex and high Al saturation. In areas of crop-livestock systems, liming corrects the surface acidity potential. However, this practice can leave the subsoil with excess aluminum and lack of calcium, which inhibit root growth and affect the absorption of water and nutrients. The application of gypsum allows the improvement of the subsoil, reducing Al saturation and increasing levels of calcium and sulfur. The aim of this study was to investigate changes in the soil chemical properties of a Haplorthox soil in integrated crop-livestock system (ICL) with Brachiaria brizantha cv. Marandu and Piatã, Brachiaria ruziziensis with gypsum and liming application. This study was conducted at the Instituto de Zootecnia, Nova Odessa/SP, a pasture established on a soil with medium texture (61.4% s

ês.