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The increasing demand for efficiently growing vegetation in greenhouses requires continual improvement of the control of the growth environment experienced by the plants. The single most important factor in maximizing the crop's growth is the quantity, quality, and geometrical distribution of radiation intercepted at every moment. Few available greenhouse coverings are capable of responding to changes in sunlight conditions by themselves, limiting the grower's control: they must use additional technologies, including screens, artificial lighting, heating, and cooling. This review considers existing efforts in providing adaptable greenhouse covering systems and advanced optical materials for controlling the color, intensity, and/or distribution of sunlight transmitted into greenhouse‐like structures by describing existing static materials and their responsive equivalents. This work also offers speculation on potential applications of other light‐control elements, mostly designed for use in the urban environment that can be adapted for greenhouse use in the future. [ABSTRACT FROM AUTHOR]

Research on closed plant production systems, such as artificially illuminated and highly insulated plant factories, has offered perspectives for urban food production but more insight is needed into their resource use efficiency. This paper assesses the potential of this ‘novel’ system for production in harsh climates with either low or high temperatures and solar radiation levels. The performance of plant factories is compared with cultivation in traditional greenhouses by analysing the use of resources in the production of lettuce. We applied advanced climate models for greenhouses and buildings, coupled with a lettuce model that relates growth to microclimate. This analysis was performed for three different climate zones and latitudes (24–68°N). In terms of energy efficiency, plant factories (1411 MJ kg −1 dry weight) outperform even the most efficient greenhouse (Sweden with artificial illumination; 1699 MJ kg −1 dry weight). Additionally, plant factories achieve higher productivity for all other resources (water, CO 2 and land area). With respect to purchased energy, however, greenhouses excel as they use freely available solar energy for photosynthesis. The production of 1 kg dry weight of lettuce requires an input of 247 kWhe in a plant factory, compared to 70, 111, 182 and 211 kWhe in greenhouses in respectively the Netherlands, United Arab Emirates and Sweden (with and without additional artificial illumination). The local scarcity of resources determines the suitability of production systems. Our quantitative analysis provides insight into the effect of external climate on resource productivity in plant factories and greenhouses. By elucidating the impact of the absence of solar energy, this provides a starting point for determining the economic viability of plant factories. [ABSTRACT FROM AUTHOR]

The article presents a case study on necrotizing pneumonia and pleuritis and their association with extraintestinal pathogenic Escherichia (E.) coli in Panthera tigris, also known as a tiger cub. E. coli causes diseases both in animals and humans wherein the affected organs are those outside the alimentary canal. Inflammatory cells, fibrin strands, and edema were found in the alveolar spaces.

The aim of this study was to analyse air exchange and temperature distribution in a greenhouse with combined mechanical and natural ventilation and to design more efficient mechanical ventilation systems. For this purpose, a computational fluid dynamics (CFD) model of the greenhouse was used. Three configurations were considered: Configuration 1 (mechanical ventilation and closed roof ventilators), Configurations 2 and 3 (mechanical ventilation and roof ventilators open 30% and 100%, respectively). After validation, the CFD model was used to improve the design of the greenhouse mechanical ventilation system in each of the three configurations analyzed. Four greenhouse lengths, 28 m, 50 m, 75 m and 100 m, were used in the simulations. Compared to fan ventilation only, roof ventilation improved the climate of fan-ventilated greenhouses in terms of the air exchange rate (22%) and climate uniformity because the internal air was mixed better than with mechanical ventilation only. As the greenhouse length increased, more advantages were achieved with natural ventilation compared to mechanical ventilation. For most configurations, there was a strong linear correlation between temperature gradient and greenhouse length. The greenhouse whose regression line had the steepest slope was the one with closed roof ventilators. Increasing the fan capacity produced a general reduction in temperature, but the effect was less intense for the greenhouses with open roof ventilators. Compared to box inlet ventilators, an enlarged continuous inlet in the wall opposite the fans increased overall system performance because it eliminated backflow recirculation zones, which are prone to produce high temperatures. [ABSTRACT FROM AUTHOR]

The present study was conducted to study the effect of pre-harvest factors such as salinity and greenhouse air CO 2 enrichment on the quality of a high commercial value, tomato cultivar. The experiment was carried out in two identical, adjacent multispan greenhouses, with polyethylene plastic covering. Hybrid Raf (cv. Delizia), tomato plants, were exposed to two treatments of salinity (5 and 7 dS m −1 ) and two ambient CO 2 concentrations (350 and 800 μmol mol −1 ) in which CO 2 enrichment was applied during the daytime according to a strategy linked to ventilation. The high salinity treatment (7 dS m −1 ) increased firmness (N), total soluble solids content (SSC), titratable acidity (TA) and the percentage of dry matter of the fruit (% DM), however, the pH was reduced. In return, CO 2 enrichment did not affect firmness, TA and pH, whereas SSC and % DM were increased. On the other hand, the climatic variations as temperature, radiation and CO 2 concentration, during the period of fruit development (PFD) affected its duration. The effective degree days (EDDs) model that combines temperature and radiation was used to study the relationship with the PFD and quality parameters. A good correlation was found between PFD and EDDs ( r 2 = 0.95). Thus the thermal time model by incorporating radiation can be recommended for our region to predict the period of fruit development in a hybrid Raf tomato crop. With respect to quality parameters, an increasing trend was observed between fruit firmness in high salinity conditions and the EDDs though the correlation was weak ( r 2 = 0.50). We did not find a relationship on SSC, TA, pH and % DM. CO 2 enrichment shortened two days of the PFD and salinity did not affect this parameter. According to the results, CO 2 enrichment allows increasing the production of a high value commercial crop grown under saline conditions by reducing the time needed for complete fruit development without compromising organoleptic quality. [ABSTRACT FROM AUTHOR]