Closed-loop model re-identification of processes under MPC with zone control

This work deals with a procedure for model re-identification of a process in closed loop with ail already existing commercial MPC. The controller considered here has a two-layer structure where the upper layer performs a target calculation based on a simplified steady-state optimization of the process. Here, it is proposed a methodology where a test signal is introduced in a tuning parameter of the target calculation layer. When the outputs are controlled by zones instead of at fixed set points, the approach allows the continuous operation of the process without an excessive disruption of the operating objectives as process constraints and product specifications remain satisfied during the identification test. The application of the method is illustrated through the simulation of two processes of the oil refining industry. (c) 2008 Elsevier Ltd. All rights reserved.

Traceability system in cod fishing

The objective of this research was to examine how various factors in Icelandic cod fishing can influence the quality of the raw material, using traceability systems to link these factors, and how transfer that knowledge and techniques to the Brazilian seafood industry. Data were collected in 2007 and analysed, to find a functional relationship between various quality factors. The analysis, showed, that there is a correlation between the number of parasites in the fillets and location of the fishing ground. It also showed that fishing ground and volume in haul can influence gaping, and that fillet yield differs between fishing grounds. These conclusions could only be drawn because of the ability to trace the fish from catch and all the way through processing. Recommendations drawn from this research to the Brazilian Competent Authority are to revise the countries fisheries legislation in order to enable the implementation of a traceability system that could be used as a tool to improve the quality of the raw material. (C) 2010 Elsevier Ltd. All rights reserved.

Inhibition of Auxin Transport from the Ovary or from the Apical Shoot Induces Parthenocarpic Fruit-Set in Tomato Mediated by Gibberellins

Fruit-set in tomato (Solanum lycopersicum) depends on gibberellins and auxins (GAs). Here, we show, using the cv MicroTom, that application of N-1-naphthylphthalamic acid (NPA; an inhibitor of auxin transport) to unpollinated ovaries induced parthenocarpic fruit-set, associated with an increase of indole-3-acetic acid (IAA) content, and that this effect was negated by paclobutrazol (an inhibitor of GA biosynthesis). NPA-induced ovaries contained higher content of GA(1) (an active GA) and transcripts of GA biosynthetic genes (SlCPS, SlGA20ox1, and -2). Interestingly, application of NPA to pollinated ovaries prevented their growth, potentially due to supraoptimal IAA accumulation. Plant decapitation and inhibition of auxin transport by NPA from the apical shoot also induced parthenocarpic fruit growth of unpollinated ovaries. Application of IAA to the severed stump negated the plant decapitation effect, indicating that the apical shoot prevents unpollinated ovary growth through IAA transport. Parthenocarpic fruit growth induced by plant decapitation was associated with high levels of GA(1) and was counteracted by paclobutrazol treatment. Plant decapitation also produced changes in transcript levels of genes encoding enzymes of GA biosynthesis (SlCPS and SlGA20ox1) in the ovary, quite similar to those found in NPA-induced fruits. All these results suggest that auxin can have opposing effects on fruit-set, either inducing (when accumulated in the ovary) or repressing (when transported from the apical shoot) that process, and that GAs act as mediators in both cases. The effect of NPA application and decapitation on fruit-set induction was also observed in MicroTom lines bearing introgressed DWARF and SELF-PRUNING wild-type alleles.

Hormonal modulation of photomorphogenesis-controlled anthocyanin accumulation in tomato (Solanum lycopersicum L. cv Micro-Tom) hypocotyls: Physiological and genetic studies

Hormones are likely to be important factors modulating the light-dependent anthocyanin accumulation. Here we analyzed anthocyanin contents in hypocotyls of near isogenic Micro-Tom (MT) tomato lines carrying hormone and phytochrome mutations, as single and double-mutant combinations. In order to recapitulate mutant phenotype, exogenous hormone applications were also performed Anthocyanin accumulation was promoted by exogenous abscisic acid (ABA) and inhibited by gibberellin (GA), in accordance to the reduced anthocyanin contents measured in ABA-deficient (notabills) and GA-constitutive response (procera) mutants. Exogenous cytokinin also enhanced anthocyanin levels in MT hypocotyls. Although auxin-insensitive chageotropica mutant exhibited higher anthocyanin contents, pharmacological approaches employing exogenous auxin and a transport inhibitor did not support a direct role of the hormone in anthocyanin accumulation Analysis of mutants exhibiting increased ethylene production (epwastic) or reduced sensitivity (Never ripe), together with pharmacological data obtained from plants treated with the hormone, indicated a limited role for ethylene in anthocyanin contents. Phytochrome-deficiency (aurea) and hormone double-mutant combinations exhibited phenotypes suggesting additive or synergistic interactions, but not fully espistatic ones, in the control of anthocyanin levels in tomato hypocotyls. Our results indicate that phytochrome-mediated anthocyanin accumulation in tomato hypocotyls is modulated by distinct hormone classes via both shared and independent pathways. (C) 2010 Elsevier Ireland Ltd. All rights reserved

An estimate of biometric parameters in eucalyptus clone plantations in Southern Bahia: an application of the airborne laser scanning (ALS) technology

The application of airborne laser scanning (ALS) technologies in forest inventories has shown great potential to improve the efficiency of forest planning activities. Precise estimates, fast assessment and relatively low complexity can explain the good results in terms of efficiency. The evolution of GPS and inertial measurement technologies, as well as the observed lower assessment costs when these technologies are applied to large scale studies, can explain the increasing dissemination of ALS technologies. The observed good quality of results can be expressed by estimates of volumes and basal area with estimated error below the level of 8.4%, depending on the size of sampled area, the quantity of laser pulses per square meter and the number of control plots. This paper analyzes the potential of an ALS assessment to produce certain forest inventory statistics in plantations of cloned Eucalyptus spp with precision equal of superior to conventional methods. The statistics of interest in this case were: volume, basal area, mean height and dominant trees mean height. The ALS flight for data assessment covered two strips of approximately 2 by 20 Km, in which clouds of points were sampled in circular plots with a radius of 13 m. Plots were sampled in different parts of the strips to cover different stand ages. The clouds of points generated by the ALS assessment: overall height mean, standard error, five percentiles (height under which we can find 10%, 30%, 50%,70% and 90% of the ALS points above ground level in the cloud), and density of points above ground level in each percentile were calculated. The ALS statistics were used in regression models to estimate mean diameter, mean height, mean height of dominant trees, basal area and volume. Conventional forest inventory sample plots provided real data. For volume, an exploratory assessment involving different combinations of ALS statistics allowed for the definition of the most promising relationships and fitting tests based on well known forest biometric models. The models based on ALS statistics that produced the best results involved: the 30% percentile to estimate mean diameter (R(2)=0,88 and MQE%=0,0004); the 10% and 90% percentiles to estimate mean height (R(2)=0,94 and MQE%=0,0003); the 90% percentile to estimate dominant height (R(2)=0,96 and MQE%=0,0003); the 10% percentile and mean height of ALS points to estimate basal area (R(2)=0,92 and MQE%=0,0016); and, to estimate volume, age and the 30% and 90% percentiles (R(2)=0,95 MQE%=0,002). Among the tested forest biometric models, the best fits were provided by the modified Schumacher using age and the 90% percentile, modified Clutter using age, mean height of ALS points and the 70% percentile, and modified Buckman using age, mean height of ALS points and the 10% percentile.

A positive growth response to NaCl applications in Eucalyptus plantations established on K-deficient soils

Contrasting responses of Eucalyptus trees to K fertilizer applications have been reported on soils with low K contents. A complete randomized block experiment was set up in Brazil to test the hypothesis that large atmospheric deposits of NaCl in coastal regions might lead to a partial substitution of K by Na in Eucalyptus physiology and enhance tree growth. Treatments with application of 1.5, 3.0, 4.5 kmol K ha(-1) (K(1.5), K(3.0), 1(4.5, respectively) as KCl, 3.0 kmol K ha(-1) applied as K(2)SO(4), 3.0 kmol Na ha(-1) (Na(3.0)) as NaCl commercialized for cattle feeding, and a mixture of 1.5 kmol K + 1.5 kmol Na ha(-1) (K(1.5) + Na(1.5)) were compared to a control treatment (C) with no K and Na applications. All the plots were fertilized with large amounts of the other nutrients. A positive effect of NaCl applications on the growth of E. grandis trees was observed. NaCl and KCl additions in treatments Na(3.0) and K(3.0) increased above-ground biomass by 56% and 130% three years after planting, respectively, in comparison with the C treatment. By contrast, accumulated litterfall up to age 3 years was not significantly modified. NaCl applications in the Na(3.0) treatment significantly increased Na accumulation in above-ground tree components but did not modify K accumulation, whatever the sampling age. A partial substitution of K by Na in tree physiology, as observed for various agricultural crops, might explain this behaviour. Our results suggest the possibility of applying inexpensive K fertilizers, which are less purified in Na, and explain why high yields are achieved without K fertilizer applications in areas with large dry depositions of marine aerosols. Further investigations are necessary to identify the processes involving Na in Eucalyptus tree physiology. (C) 2009 Elsevier B.V. All rights reserved.

Fungal pathogens as classical biological control agents against arthropods

Fungal entomopathogens have been used more frequently than other types of pathogens for classical biological control. Among 136 programs using different groups of arthropod pathogens, 49.3% have introduced fungal pathogens (including both the traditional fungi and microsporidia). The most commonly introduced species was Metarhizium anisopliae (Metschnikoff) Sorokin, with 13 introductions, followed by Entomophaga maimaiga Humber, Shimazu & Soper, which was released seven times. The majority of introduction programs have focused on controlling invasive species of insects or mites (70.7%) rather than on native hosts (29.4%). Almost half of the introductions of traditional fungi targeted species of Hemiptera and 75% of the microsporidia introduced have been introduced against lepidopteran species. The United States was the country where most introductions of fungi took place (n = 24). From 1993 to 2007, no arthropod pathogens were released in the US due to the rigorous regulatory structure, but in 2008 two species of microsporidia were introduced against the gypsy moth, Lymantria dispar (L.). Establishment of entomopathogenic fungi in programs introducing traditional fungi was 32.1% and establishment was 50.0% for programs introducing microsporidia. In some programs, releases have resulted in permanent successful establishment with no non-target effects. In summary, classical biological control using fungal entomopathogens can provide a successful and environmentally friendly avenue for controlling arthropod pests, including the increasing numbers of invasive non-native species.

Role of entomopathogenic fungi in the control of Tetranychus evansi and Tetranychus urticae (Acari: Tetranychidae), pests of horticultural crops

The spider mites Tetranychus urticae Koch and Tetranychus evansi Baker and Pritchard are important pests of horticultural crops. They are infected by entomopathogenic fungi naturally or experimentally. Fungal pathogens known to cause high infection in spider mite populations belong to the order Entomophthorales and include Neozygites spp. Studies are being carried out to develop some of these fungi as mycoacaricides, as standalone control measures in an inundative strategy to replace the synthetic acaricides currently in use or as a component of integrated mite management. Although emphasis has been put on inundative releases, entomopathogenic fungi can also be used in classical, conservation and augmentative biological control. Permanent establishment of an exotic agent in a new area of introduction may be possible in the case of spider mites. Conservation biological control can be achieved by identifying strategies to promote any natural enemies already present within crop ecosystems, based on a thorough understanding of their biology, ecology and behaviour. Further research should focus on development of efficient mass production systems, formulation, and delivery systems of fungal pathogens.

Drip fungigation in early blight control of tomato

The aim was to verify if the fungigation via drip irrigation is an alternative to the conventional method of spraying on tomato for controlling early blight. Tomato plants (variety Santa Clara) were grown in pots inside a greenhouse. Fifty days after transplanting, the plants were inoculated with Alternaria solani and treated with four different fungicides: azoxystrobin (8 g 100 L(-1)), difeconazole (50 mL 100 L(-1)), metiram+piraclostrobin (200 g 100 L(-1)) and tebuconazole (100 mL 100 L(-1)) using two applications methods: conventional spraying and fiingigation dripping. The control plants did not receive fungicide application. To assess the severity of the disease, we used a rating scale expressed as the area under the disease progress curve (AUDPC) and production factors, such as number, weight and average diameter of the fruit and its productivity. The experimental design was completely randomized in factorial scheme 4 x 2 + 1 with eight replicates. Each plot had one plant in one pot. A 27% reduction in disease severity was observed when compared with the control plants, with no significant difference noted regarding the application method. The number of fruits did not statistically differ between the treatments. The average weight and diameter of the fruits were superior in the plants that had fungicide application compared to the control plant, reflecting an increase in productivity. Fungigation through water dripping is an alternative to the conventional method of spraying cultured tomatoes.

Crop rotation in center-pivot for phytonematode control: density variation, pathogenicity and crop loss estimation

Crop rotation in center-pivot for phytonematode control: density variation, pathogenicity and crop loss estimation A field study conducted over three consecutive years, on a farm using crop rotation system under center-pivot and infested with the nematodes Pratylenchus brachyurus, P. zeae, Meloidogyne incognita, Paratrichodorus minor, Helicotylenchus dihystera, Mesocriconema ornata and M. onoense, demonstrated that intensive crop systems provide conditions for the maintenance of high densities of polyphagous phytonematodes. Of the crops established on the farm (cotton, maize, soybean and cowpea), cotton and soybean suffered the most severe crop losses, caused respectively by M. incognita and P. brachyurus. Since maize is a good host for both nematodes, but tolerant of M. incognita, its exclusion from cropping system would be favorable to the performance of cotton, soybean and cowpea. Results from experiments carried out in controlled conditions confirmed the pathogenicity of P. brachyurus on cotton. Additional management with genetic resistance was useful in fields infested with M. incognita, although the soybean performance was affected by low resistance of the cultivars used for P. brachyurus. In conclusion, crop rotation must be carefully planned in areas infested with polyphagous nematodes, specifically in the case of occurrence of two or more major pathogenic nematodes.

Copper sprays and windbreaks for control of citrus canker on young orange trees in southern Brazil

The benefit of windbreaks and copper sprays for control of citrus canker caused by Xanthomonas axonopodis pv. citri was investigated in a commercial citrus orchard located in a citrus canker endemic area in southern Brazil. Control of canker was evaluated as incidence and severity of lesions on foliage and by the effect on premature leaf and fruit drop for three production seasons. Effect of the treatments on fruit production was evaluated as incidence of citrus canker on prematurely abscised fruits and harvested fruits. Copper application significantly reduced damage to foliage and fruit, while windbreaks made little contribution to disease control. Copper sprays increased fruit yield for 3 years. This could be attributed to lower incidence of fruit with lesions and fewer fruits abscised due to canker infection. Incidence and severity on the leaves were inversely related to the number of fruits harvested per tree and directly related to the number of fruits abscised per tree. Published by Elsevier Ltd.

Transmission of Methylobacterium mesophilicum by Bucephalogonia xanthophis for Paratransgenic Control Strategy of Citrus Variegated Chlorosis

Methylobacterium mesophilicum, originally isolated as an endophytic bacterium from citrus plants, was genetically transformed to express green fluorescent protein (GFP). The GFP-labeled strain of M. mesophilicum was inoculated into Catharanthus roseus (model plant) seedlings and further observed colonizing its xylem vessels. The transmission of this endophyte by Bucephalogonia xanthophis, one of the insect vectors that transmit Xylella fastidiosa subsp. pauca, was verified by insects feeding from fluids containing the GFP bacterium followed by transmission to plants and isolating the endophyte from C. roseus plants. Forty-five days after inoculation, the plants exhibited endophytic colonization by M. mesophilicum, confirming this bacterium as a nonpathogenic, xylem-associated endophyte. Our data demonstrate that M. mesophilicum not only occupy the same niche of X. fastidiosa subsp. pauca inside plants but also may be transmitted by B. xanthophis. The transmission, colonization, and genetic manipulation of M. mesophilicum is a prerequisite to examining the potential use of symbiotic control to interrupt the transmission of X. fastidiosa subsp. pauca, the bacterial pathogen causing Citrus variegated chlorosis by insect vectors.

Biochemical responses of glyphosate resistant and susceptible soybean plants exposed to glyphosate

Glyphosate is a wide spectrum, non-selective, post-emergence herbicide. It acts on the shikimic acid pathway inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), thus obstructing the synthesis of tryptophan, phenylalanine, tyrosine and other secondary products, leading to plant death. Transgenic glyphosate-resistant (GR) soybean [Glycine max (L.)] expressing an glyphosate-insensitive EPSPS enzyme has provided new opportunities for weed control in soybean production. The effect of glyphosate application on chlorophyll level, lipid peroxidation, catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GOPX) and superoxide dismutase (SOD) activities, soluble amino acid levels and protein profile, in leaves and roots, was examined in two conventional (non-GR) and two transgenic (GR) soybean. Glyphosate treatment had no significant impact on lipid peroxidation, whilst the chlorophyll content decreased in only one non-GR cultivar. However, there was a significant increase in the levels of soluble amino acid in roots and leaves, more so in non-GR than in GR soybean cultivars. Root CAT activity increased in non-GR cultivars and was not altered in GR cultivars. In leaves, CAT activity was inhibited in one non-GR and one GR cultivar. GOPX activity increased in one GR cultivar and in both non-GR cultivars. Root APX activity increased in one GR cultivar. The soluble protein profiles as assessed by 1-D gel electrophoresis of selected non-GR and GR soybean lines were unaffected by glyphosate treatment. Neither was formation of new isoenzymes of SOD and CAT observed when these lines were treated by glyphosate. The slight oxidative stress generated by glyphosate has no relevance to plant mortality. The potential antioxidant action of soluble amino acids may be responsible for the lack of lipid peroxidation observed. CAT activity in the roots and soluble amino acids in the leaves can be used as indicators of glyphosate resistance.

Canonical discriminant analysis applied to broiler chicken performance

The mechanisms involved in the control of growth in chickens are too complex to be explained only under univariate analysis because all related traits are biologically correlated. Therefore, we evaluated broiler chicken performance under a multivariate approach, using the canonical discriminant analysis. A total of 1920 chicks from eight treatments, defined as the combination of four broiler chicken strains (Arbor Acres, AgRoss 308, Cobb 500 and RX) from both sexes, were housed in 48 pens. Average feed intake, average live weight, feed conversion and carcass, breast and leg weights were obtained for days 1 to 42. Canonical discriminant analysis was implemented by SAS((R)) CANDISC procedure and differences between treatments were obtained by the F-test (P < 0.05) over the squared Mahalanobis` distances. Multivariate performance from all treatments could be easily visualised because one graph was obtained from two first canonical variables, which explained 96.49% of total variation, using a SAS((R)) CONELIP macro. A clear distinction between sexes was found, where males were better than females. Also between strains, Arbor Acres, AgRoss 308 and Cobb 500 (commercial) were better than RX (experimental), Evaluation of broiler chicken performance was facilitated by the fact that the six original traits were reduced to only two canonical variables. Average live weight and carcass weight (first canonical variable) were the most important traits to discriminate treatments. The contrast between average feed intake and average live weight plus feed conversion (second canonical variable) were used to classify them. We suggest analysing performance data sets using canonical discriminant analysis.