DIFFERENT SOILLESS CULTURE SYSTEMS AND THEIR MANAGEMENT

Soilless culture is growing plants without use of soil as a rooting medium, and divided into water culture and substrate culture. Among the water culture techniques, float hydroponics is adopted for the cultivation of fresh-cut leafy vegetables and aromatic plants. Substrate culture by using plastic bags has been applied successfully at commercial level for fruiting vegetables. Production scale, crops, growing cycles and length of each cycle, cost and management skills should be considered as well as environmental concerns in the decision of soilless culture system. Therefore, closed loop systems have gained importance for increasing sustainability in soilless cultivation. This presentation aims to summarize different soilless culture systems and the potential of their use in vegetable production

Efectos de la nutrición y de Bacillus amyloliquefaciens en tomate (Solanum lycopersicum, L.) cultivado en perlita

Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria that, as their name suggests, promote plant growth. However, they can also be of help in the biological control of plant diseases. This study reports the effects of two different commercially available strains of Bacillus amyloliquefaciens (FZB24 and FZB42) on tomato production in open and closed systems in the presence of different amounts of nutrients. Three factors were tested: (1) the type of nutrition system (open or closed), (2) the concentration of the nutrient solution (full or half strength), and (3) the PGPR applied (either B. amyloliquefaciens FZB24 or B. amyloliquefaciens FZB42, or a no-PGPR control). Perlite was used as the growth medium. Variables related to water use efficiency, yield and fruit quality were assessed. The use of half strength nutrient solution was sufficient for full growth in the open system in both spring and autumn seasons. However, the same strength nutrient solution was associated with reduced yields in the closed system during the autumn season. The application of either strain of B. amyloliquefaciens increased the yield of the tomato plants by 8-9% in the open system in the spring, whereas they had an adverse effect on yield in the closed system under half strength nutrient solution conditions during the autumn.Las rhizobacterias promotoras del crecimiento de las plantas (PGPR) son bacterias que viven libres y, como su nombre indica, promueven el crecimiento de las plantas. Sin embargo, también pueden ser de ayuda en el control biológico de las enfermedades de las plantas. En este estudio se investigaron los efectos de dos cepas comerciales de Bacillus amyloliquefaciens (FZB24 y FZB42) sobre la producción de tomate en sistemas abiertos y cerrados, en presencia de diferentes cantidades de nutrientes. Los tratamientos fueron: (1) tipo de sistema de nutrición (abierto o cerrado), (2) concentración de nutrientes (solución nutritiva completa o incompleta), (3) la PGPR aplicada (B. amyloliquefaciens FZB24, B. amyloliquefaciens FZB42, o un control sin PGPR). Se utilizó perlita como medio de crecimiento. Se evaluaron las variables relacionadas con la eficiencia del uso del agua, producción de tomate y calidad del fruto. La solución de nutrientes menos concentrada fue suficiente para un pleno crecimiento en el sistema abierto en ambas estaciones (primavera y otoño). Sin embargo, la misma solución de nutrientes disminuyó en otoño la producción en el sistema cerrado. La aplicación de ambas cepas de B. amyloliquefaciens aumentó la producción de las plantas de tomate un 8-9% en el sistema abierto en primavera, mientras que tuvo un efecto adverso sobre la producción en otoño en el sistema cerrado con la solución menos concentrada

Strategies for the evolution of sex

We find that the hypothesis made by Jan, Stauffer and Moseley [Theory in Biosc., 119, 166 (2000)] for the evolution of sex, namely a strategy devised to escape extinction due to too many deleterious mutations, is sufficient but not necessary for the successful evolution of a steady state population of sexual individuals within a finite population. Simply allowing for a finite probability for conversion to sex in each generation also gives rise to a stable sexual population, in the presence of an upper limit on the number of deleterious mutations per individual. For large values of this probability, we find a phase transition to an intermittent, multi-stable regime. On the other hand, in the limit of extremely slow drive, another transition takes place to a different steady state distribution, with fewer deleterious mutations within the asexual population.Comment: RevTeX, 11 pages, multicolumn, including 12 figure

Multi-Particle Collision Dynamics -- a Particle-Based Mesoscale Simulation Approach to the Hydrodynamics of Complex Fluids

In this review, we describe and analyze a mesoscale simulation method for fluid flow, which was introduced by Malevanets and Kapral in 1999, and is now called multi-particle collision dynamics (MPC) or stochastic rotation dynamics (SRD). The method consists of alternating streaming and collision steps in an ensemble of point particles. The multi-particle collisions are performed by grouping particles in collision cells, and mass, momentum, and energy are locally conserved. This simulation technique captures both full hydrodynamic interactions and thermal fluctuations. The first part of the review begins with a description of several widely used MPC algorithms and then discusses important features of the original SRD algorithm and frequently used variations. Two complementary approaches for deriving the hydrodynamic equations and evaluating the transport coefficients are reviewed. It is then shown how MPC algorithms can be generalized to model non-ideal fluids, and binary mixtures with a consolute point. The importance of angular-momentum conservation for systems like phase-separated liquids with different viscosities is discussed. The second part of the review describes a number of recent applications of MPC algorithms to study colloid and polymer dynamics, the behavior of vesicles and cells in hydrodynamic flows, and the dynamics of viscoelastic fluids

Treatments for people who use anabolic androgenic steroids: a scoping review.

BACKGROUND: A growing body of evidence suggests that anabolic androgenic steroids (AAS) are used globally by a diverse population with varying motivations. Evidence has increased greatly in recent years to support understanding of this form of substance use and the associated health harms, but there remains little evidence regarding interventions to support cessation and treat the consequences of use. In this scoping review, we identify and describe what is known about interventions that aim to support and achieve cessation of AAS, and treat and prevent associated health problems. METHODS: A comprehensive search strategy was developed in four bibliographic databases, supported by an iterative citation searching process to identify eligible studies. Studies of any psychological or medical treatment interventions delivered in response to non-prescribed use of AAS or an associated harm in any setting were eligible. RESULTS: In total, 109 eligible studies were identified, which included case reports representing a diverse range of disciplines and sources. Studies predominantly focussed on treatments for harms associated with AAS use, with scant evidence on interventions to support cessation of AAS use or responding to dependence. The types of conditions requiring treatment included psychiatric, neuroendocrine, hepatic, kidney, cardiovascular, musculoskeletal and infectious. There was limited evidence of engagement with users or delivery of psychosocial interventions as part of treatment for any condition, and of harm reduction interventions initiated alongside, or following, treatment. Findings were limited throughout by the case report study designs and limited information was provided. CONCLUSION: This scoping review indicates that while a range of case reports describe treatments provided to AAS users, there is scarce evidence on treating dependence, managing withdrawal, or initiating behaviour change in users in any settings. Evidence is urgently required to support the development of effective services for users and of evidence-based guidance and interventions to respond to users in a range of healthcare settings. More consistent reporting in articles of whether engagement or assessment relating to AAS was initiated, and publication within broader health- or drug-related journals, will support development of the evidence base

Effects of nutrition and "Bacillus amyloliquefaciens" on tomato ("Solanum lycopersicum L.") growing in perlite

Las rhizobacterias promotoras del crecimiento de las plantas (PGPR) son bacterias que viven libres y, como su nombre indica, promueven el crecimiento de las plantas. Sin embargo, también pueden ser de ayuda en el control biológico de las enfermedades de las plantas. En este estudio se investigaron los efectos de dos cepas comerciales de Bacillus amyloliquefaciens (FZB24 y FZB42) sobre la producción de tomate en sistemas abiertos y cerrados, en presencia de diferentes cantidades de nutrientes. Los tratamientos fueron: (1) tipo de sistema de nutrición (abierto o cerrado), (2) concentración de nutrientes (solución nutritiva completa o incompleta), (3) la PGPR aplicada (B. amyloliquefaciens FZB24, B. amyloliquefaciens FZB42, o un control sin PGPR). Se utilizó perlita como medio de crecimiento. Se evaluaron las variables relacionadas con la eficiencia del uso del agua, producción de tomate y calidad del fruto. La solución de nutrientes menos concentrada fue suficiente para un pleno crecimiento en el sistema abierto en ambas estaciones (primavera y otoño). Sin embargo, la misma solución de nutrientes disminuyó en otoño la producción en el sistema cerrado. La aplicación de ambas cepas de B. amyloliquefaciens aumentó la producción de las plantas de tomate un 8-9% en el sistema abierto en primavera, mientras que tuvo un efecto adverso sobre la producción en otoño en el sistema cerrado con la solución menos concentrada.Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria that, as their name suggests, promote plant growth. However, they can also be of help in the biological control of plant diseases. This study reports the effects of two different commercially available strains of Bacillus amyloliquefaciens (FZB24 and FZB42) on tomato production in open and closed systems in the presence of different amounts of nutrients. Three factors were tested: (1) the type of nutrition system (open or closed), (2) the concentration of the nutrient solution (full or half strength), and (3) the PGPR applied (either B. amyloliquefaciens FZB24 or B. amyloliquefaciens FZB42, or a no-PGPR control). Perlite was used as the growth medium. Variables related to water use efficiency, yield and fruit quality were assessed. The use of half strength nutrient solution was sufficient for full growth in the open system in both spring and autumn seasons. However, the same strength nutrient solution was associated with reduced yields in the closed system during the autumn season. The application of either strain of B. amyloliquefaciens increased the yield of the tomato plants by 8-9% in the open system in the spring, whereas they had an adverse effect on yield in the closed system under half strength nutrient solution conditions during the autumn

Effect of different irrigation schedules, substrates and substrate volumes on fruit quality and yield of greenhouse

This study was conducted to determine the effects of three irrigation schedules in combination with locally available substrates and different bag volumes on yield, fruit quality and water consumption of tomato (cv. Fantastic). The substrates were: (1) perlite, (2) pumice, (3) volcanic ash, (4) perlite + peat (4:1, v/v), (5) pumice + peat (4:1, v/v) and (6) volcanic ash + peat (4:1, v/v). Irrigation was carried out according to the drainage volume as (1) once, (2) twice and (3) four times a day. The experimental design was split split plots with 3 replicates. The main plots, subplots and sub-subplots were irrigation schedule, substrate volume (4 and 8 litres) and substrate, respectively. Cumulative yield at two week intervals and some quality parameters (average fruit weight, total soluble solids, total dry matter content, pH, EC, vitamin C, titratable acidity) were determined. Experimental factors were found to significantly affect on yield after the 10th week. The higher total yields were obtained from plants grown in perlite+peat (7.4 kg/plant) and perlite (7.2 kg/plant). 8 litres rooting volume per plant resulted in a higher total yield (7.4 kg/plant) in comparison with 4 litres (6.2 kg/plant). Total yield obtained from the plants irrigated once a day (6.4 kg/plant) was lower than those obtained from the plants irrigated twice (6.9 kg/plant) and four times (7.1 kg/plant) daily. Fruit quality parameters varied according to treatments and sampling dates

Effects of oxyfertigation and plant growth promoting rhizobacteria on greenhouse lettuce grown in perlite

This study was conducted in order to determine the effects of oxygen enrichment of nutrient solution coupled with plant growth promoting rhizobacteria on soilless grown iceberg lettuce (cv. ‘Papiro’) production. Seeds were treated with Bacillus subtilis, Pseudomonas putida, P. fluorescens, P. punonensis and combined application of B. subtilis + P. fluorescens and were sown into vermicompost : peat (1 : 1.5, v/v) mixture on January 14th, 2015. After germination in growth chamber, seedlings were moved to a greenhouse for seedling growing till they were ready for planting. Seedlings were transplanted to the polyethylene greenhouse 35 days after sowing. Perlite as growing medium was used in open-system soilless culture. Nutrient solution was aerated with an air compressor and applied to plants 2 days after planting with drip irrigation. To diffuse oxygen into nutrient solution in large bubbles, a circular air-stone commonly used in fisheries was used. The nutrient solution without oxyfertigation and plants not treated with bacteria constituted the control treatment. Experiments were conducted in randomized plots design with 2 factors and 3 replications. Heads were harvested 2 months after transplanting. Yield and head quality parameters of head were determined. It was concluded that oxygen enrichment of nutrient solution through a compressor (aeration) provided increases in yield and plant growth. Especially root development, head size and leaf number were higher in plants grown with aerated nutrient solution. Among the tested bacteria, B. subtilis, P. fluorescens and B. subtilis + P. fluorescens were found promising due to the their higher performance under aerated conditions on greenhouse lettuce grown in perlite