Las propiedades físicas de los sustratos especialmente las relacionadas con la disponibilidad de agua-aire para las raíces de las plantas son las más importantes dentro del estudio de estos materiales usados en cultivos en contenedores. Para un óptimo crecimiento de la planta un sustrato debe contener suficiente cantidad de agua y aire y ambos estar disponibles. A nivel mundial el estudio de las propiedades que determinan esta disponibilidad comenzó desde las ciencias del suelo y fue adaptándose a las características propias de la amplia gama de productos que pueden ser utilizados, surgiendo así variables y métodos de medida específicos para la caracterización física de sustratos. En la Argentina el estudio de sustratos para plantas constituye un área de conocimiento nueva y en desarrollo, por ello exige un trabajo interdisciplinario donde hay que concordar un lenguaje común de términos técnicos, la elección de los métodos analíticos de referencia específicos y una legislación actualizada para sustratos. Haciendo un estudio crítico de la gran cantidad de información al respecto que proviene de otros países se podrán adaptar a nuestra realidad y a nuestros materiales. En esta revisión se enumeran resumidamente los más importantes conceptos a tener en cuenta para la evaluación física de sustratos a fin de que puedan servir de base para una mejor comprensión y discusión del tema. | The study of the physical properties of substrates for container plant production is very important because the water and air availability for plant roots is involved. A substrate must contain a sufficient amount of available water and air to produce an optimum plant growth and development. Worldwide, the study of the properties that determine the water and air availability started from soil sciences and has been evolving to the present existence of a great variety of products that can be used, concomitant with the identification of parameters and specific measurement methods for the physical characterization of the substrates. In Argentina, the study of plant substrates is a new area under development and it demands an interdisciplinary work that should agree with a common language of technical terms, the election of specific analytical methods of reference and an updated legislation for substrate materials. A critical assessment of the great amount of information provided by other countries could be adapted to our reality and our materials. In this review, we listed the most important concepts for the physical evaluation of the substrates as the foundation for a better understanding and discussion of the subject.

Las propiedades físicas de los sustratos especialmente las relacionadas con la disponibilidad de agua-aire para las raíces de las plantas son las más importantes dentro del estudio de estos materiales usados en cultivos en contenedores. Para un óptimo crecimiento de la planta un sustrato debe contener suficiente cantidad de agua y aire y ambos estar disponibles. A nivel mundial el estudio de las propiedades que determinan esta disponibilidad comenzó desde las ciencias del suelo y fue adaptándose a las características propias de la amplia gama de productos que pueden ser utilizados, surgiendo así variables y métodos de medida específicos para la caracterización física de sustratos. En la Argentina el estudio de sustratos para plantas constituye un área de conocimiento nueva y en desarrollo, por ello exige un trabajo interdisciplinario donde hay que concordar un lenguaje común de términos técnicos, la elección de los métodos analíticos de referencia específicos y una legislación actualizada para sustratos. Haciendo un estudio crítico de la gran cantidad de información al respecto que proviene de otros países se podrán adaptar a nuestra realidad y a nuestros materiales. En esta revisión se enumeran resumidamente los más importantes conceptos a tener en cuenta para la evaluación física de sustratos a fin de que puedan servir de base para una mejor comprensión y discusión del tema.<br>The study of the physical properties of substrates for container plant production is very important because the water and air availability for plant roots is involved. A substrate must contain a sufficient amount of available water and air to produce an optimum plant growth and development. Worldwide, the study of the properties that determine the water and air availability started from soil sciences and has been evolving to the present existence of a great variety of products that can be used, concomitant with the identification of parameters and specific measurement methods for the physical characterization of the substrates. In Argentina, the study of plant substrates is a new area under development and it demands an interdisciplinary work that should agree with a common language of technical terms, the election of specific analytical methods of reference and an updated legislation for substrate materials. A critical assessment of the great amount of information provided by other countries could be adapted to our reality and our materials. In this review, we listed the most important concepts for the physical evaluation of the substrates as the foundation for a better understanding and discussion of the subject.

Objetivando-se avaliar a utilização do biossólido como estratégia de fertilização de água na produção de Daphnia sp., foram conduzidos três experimentos no Laboratório de Nutrição de peixes do Departamento de Zootecnia da Universidade Federal de Viçosa (UFV). O primeiro experimento, conduzido no período de fevereiro e março de 2008, com duração de treze dias, teve como objetivo avaliar a utilização de diferentes fertilizantes - fosfato bicálcico (FB), biossólido (BS) e fezes de codorna (FC) na produção de plâncton. Foram utilizados 24 tanques de cimento amianto com volume útil de 100 L cada, distribuídos em delineamento inteiramente casualizado, com quatro tratamentos (os três fertilizantes e um tratamento controle, sem adubação - SA) e seis repetições. Como variáveis de controle foram avaliados a produção de Daphnia sp. e os seguintes parâmetros de qualidade da água: clorofila-a, condutividade elétrica, pH, oxigênio dissolvido, temperatura, nitrogênio amoniacal e orgânico, fósforo total e dureza total. O peso da biomassa de Daphnia sp. foi medido ao final do experimento (13º dia). Os parâmetros de controle de qualidade da água foram aferidos em três momentos ao longo do período experimental: primeiro, oitavo e décimo terceiro dias. O peso máximo da biomassa de Daphnia sp. foi encontrado nos tanques adubados com FC (36,0 g), seguido do BS (16,8 g), SA (6,8 g) e FB (5,2 g). Observou-se correspondência entre os valores de clorofila-a e o peso da biomassa de Daphnia sp., o que, muito provavelmente, reflete interações entre as comunidades fito e zooplanctônicas. No segundo experimento, realizado no período de fevereiro e março de 2008, procurou-se avaliar a aplicação de diferentes níveis de biossólidos na produção de plâncton. Foram utilizados 25 tanques, distribuídos em delineamento inteiramente casualizado com cinco tratamentos (quatro níveis de biossólidos - 25 g, 50 g, 75 g e 100 g e um tratamento controle, sem adubação) e cinco repetições. As variáveis de controle e o plano de amostragem foram os mesmos do primeiro experimento. Os pesos médios de biomassa de Daphnia sp. encontrados nos tanques foram: 16,51 g com 100 g de biossólidos; 14,63 g com 75 g de biossólidos; 14,10 g com 50 g de biossólidos; 12,85 g com 25 g de biossólidos; 5,80 g no tanque sem adubação. A aplicação de quantidades crescentes de biossólidos não comprometeu qualidade da água a ponto de torná-la inadequada ao cultivo de organismos aquáticos. Entretanto, a despeito da produção crescente de fitoplâncton de acordo com níveis crescentes de biossólidos, a produção de Daphnia sp. tendeu a estabilizar-se a partir da aplicação de 50 g de biossólidos. O terceiro experimento, realizado de março a abril de 2008 com duração de quatorze dias, envolveu a utilização de biossólidos com diferentes ajustes de NPK. Foram utilizados os mesmos 25 tanques de cimento amianto e delineamentos anteriores, com cinco tratamentos (cinco níveis de NPK em 50 g de biossólidos) e cinco repetições. As variáveis de controle e o plano de amostragem foram essencialmente os mesmos dos experimentos anteriores, porém medindo-se e nitrato e fósforo solúvel em lugar de nitrogênio orgânico e fósforo total. A aplicação de biossólidos com diferentes formulações de NPK não comprometeu a qualidade da água a ponto de torná-la inadequada ao cultivo de organismos aquáticos. Entretanto, a despeito da produção crescente de fitoplâncton de acordo com níveis crescentes de fósforo na formulação dos fertilizantes, os pesos médios de biomassa de Daphnia sp. encontrados nos tanques, em torno de 10 g, não diferiram estatisticamente para os diversos tratamentos. Os resultados sugerem que biossólidos podem ser utilizados com sucesso como fertilizante de águas para produção de fitoplâncton e de zooplâncton. | Aiming to evaluate the use of biosolid as a water fertilization strategy in the production of Daphnia sp., were conducted three experiments in the Fish Nutrition Laboratory of the Department of Animal Science of the Federal University of Viçosa (UFV). The first experiment, conducted during February and March 2008, to last for thirteen days, aimed to evaluate the use of different fertilizers - dicalcium phosphate (DF), biosolid (BS) and feces of quail (FQ). Were used 24 tanks of asbestos cement with useful volume of 100 L each, distributed in a completely randomized design, with four treatments (the three fertilizers and a control treatment without fertilization - WF) and six repetitions. As control variables were assessed the production of Daphnia sp. and the following water quality parameters: chlorophyll-a, electrical conductivity, pH, dissolved oxygen, temperature, ammonia nitrogen and organic nitrogen, total phosphorus and total hardness. The weight of the biomass of Daphnia sp. was measured at the end of the experiment (day 13). The control parameters of water quality were measured at three times during the experimental period: the first, eighth and thirteenth day. The maximum weight of the biomass of Daphnia sp. was found in tanks fertilized with FQ (35.6 grams), followed by the BS (16.8 grams), WF (6.8 g) and DF (5.2 g). There was a correlation between the values of chlorophyll-a and the weight of the biomass of Daphnia sp., which will very likely reflects interactions between phytoplankton and zooplankton communities. The results suggest that biosolids can be successfully used as water fertilizer, for production of phytoplankton and, consequently, of zooplankton. In the second experiment, carried out from February and March 2008, sought to evaluate the application of different levels of biosolids. Were used 25 tanks of asbestos cement with useful volume of 100 L each, distributed in a completely randomized design with five treatments (four levels of biosolids - 25 g, 50 g, 75 g and 100 g and a control treatment without fertilization) and five repetitions. The control variables and the sampling plan were the same as the first experiment. The weight of the biomass of Daphnia sp. was measured at the end of the experiment (day 13). The control parameters of water quality were measured at three times over the experimental period: first, eighth and thirteenth day. The average weight of biomass of Daphnia sp. found in the tanks were: 16.51 g to 100 g of biosolids; 14.63 g to 75 g of biosolids; 14.10 g to 50 g of biosolids; 12.85 g to 25 g of biosolids and 5.80 g in tank without fertilization. The results suggest that biosolids can be successfully used as water fertilizer for production of phytoplankton and, consequently, of zooplankton. The application of increasing quantities of biosolid not committed water quality to the point of making it unsuitable for the cultivation of aquatic organisms. However, despite the growing production of phytoplankton in line with increasing levels of biosolids, the production of Daphnia sp. tended to stabilize itself from the application of 50 grams of biosolids. The third experiment, conducted from March to April of 2008 with duration of fourteen days, involved the use of biosolid with different settings of NPK. Were used 25 tanks of cement and asbestos previous designs, with five treatments (five levels of NPK in 50 g of biosolids) and five repetitions. The control variables and the sampling plan was essentially the same of previous experiments, but measuring up nitrate and soluble phosphorus in place of organic nitrogen and total phosphorus. The application of biosolids with different formulations of NPK not compromised water quality to the point of making it unsuitable for the cultivation of aquatic organisms. However, despite the growing production of phytoplankton in line with increasing levels of phosphorus in the formulation of fertilizers, the weights average of Daphnia sp. biomass found in the tanks, around 10 grams, not statistically different for different treatments. In short, the results suggest that biosolids can be successfully used as water fertilizer for production of phytoplankton and zooplankton. | Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Karst caves exhibit a wide range of hydrological and hydrochemical responses to infiltration events, due to their physical heterogeneity space and dynamic variability over time, and due to non-Gaussian inputs (rain) and outputs (discharge). This paper reviews different approaches of studying seepage water in caves, in order to understand the infiltration regimen in the non-saturated zone of karst areas. As an illustration, we describe a four-year study of the active carbonate-water system the Cueva del Agua (Granada, southern Spain) that automatically logs the discharge from a stalactite. The results indicate that: (1) the drip water regime is not seasonal, but is linked instead to slow infiltration. Sudden changes in drip water regime occur due to infiltration along preferential flow paths and the draining of water of supersaturated water from reserves in the microfissure and pore system; (2) the drip rate is not linear over time. When dripping is constant, barometric oscillation of the air is the principal factor causing a chaotic a drip flow regime. Over a short period of two to three days, a mean variation in air pressure inside the cave of 10 (±3.7) mbar causes a oscillation the drip rate of 0.5 (±0.2) mm/h. The increase air translates into an the relative thickness of the gaseous phase of the drip water at the cost of the aqueous phase, so leading to a reduction the drip rate from the stalactite.

Se ha realizado un estudio de la distribución del tamaño de gotas y de las propiedades viscoelásticas lineales de emulsiones concentradas de aceite en agua, estabilizadas con diferentes proteínas (cangrejo, gluten y soja). Los sistemas estudiados siempre presentan un comportamiento típico de emulsiones altamente concentradas con un alto grado de floculación. Se ha observado que un incremento de la velocidad de agitación empleada durante la preparación o de la concentración de emulsionante dan lugar a un aumento de los módulos viscoelásticos (G&apos; y G&quot;) y a una disminución del tamaño de gotas. Por tanto se produce un reforzamiento del entramado formado por asociación de las gotas de fase dispersa y como consecuencia, un aumento en la estabilidad de las emulsiones. | Droplet Size Distribution (DSD) and linear viscoelastic properties of concentrated o/w emulsions stabilized by different proteins (crayfish, gluten and soybean) have been studied. A typical behaviour of highly concentrated emulsions with a high degree of flocculation has been found. An increase in energy input for the emulsification process or in emulsifier concentration leads to an increase in both viscoelastic moduli (G&apos;, G&quot;) as well as to a decrease in droplet size. Thus, an enhancement of the entanglement network produced by association of protein molecules that are surrounding oil droplets or are present in the continuous phase takes place, leading to a significant improvement of emulsion stability.