Potential use of ground‐based sensor technologies for weed detection     

Gerassimos G. Peteinatos  Martin Weis  Dionisio Andújar  Victor Rueda Ayala  Roland Gerhards 《Pest management science》2014,70(2):190-199

Site‐specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground‐based or near‐range sensors in combination with decision rules and precise application technologies. Near‐range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe‐ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given. © 2013 Society of Chemical Industry  相似文献   

Morphologic study of the liver of lambari (Astyanax altiparanae) with emphasis on the distribution of cytokeratin     

Chayrra Chehade  Mônica Cassel  Maria Inês Borella  Fabiano Gonçalves Costa 《Fish physiology and biochemistry》2014,40(2):571-576

Studies on the morphology of the liver of teleosts reflect some controversy in the interpretation of the data, but also provide confirmation of variations in the structure of the organ in several species. Thus, we intend to understand the specific structural organization of the liver of Astyanax altiparanae. Specimens were collected in the city of Andirá, Paraná, Brazil. The livers were processed according to histological routine for inclusion in Paraplast, and the sections were stained with HE and Mallory’s trichrome or followed the protocol for fluorescence immunohistochemistry, anti-cytokeratin. The liver of A. altiparanae was covered by a capsule of connective tissue, without delimiting lobes. The hepatocytes had an arrangement in cords around sinusoids. Melanomacrophage centers were observed. The vascular components and intrahepatic pancreatic acini were distributed between hepatocytes. Presence of cytokeratin was detected in tissues that lined the liver and endothelial cells of sinusoids. The comparison of the liver of A. altiparanae to other characids corroborates with the fact that there is variation in the morphology of the liver even between closely related species. Moreover, it appears that in this species, endothelial cells of sinusoids can synthesize the cytokeratin filaments required for the regulation of blood flow in capillaries in adults.  相似文献   

Characterization of catalytic efficiency parameters of brain cholinesterases in tropical fish     

Caio Rodrigo Dias de Assis  Amanda Guedes Linhares  Vagne Melo Oliveira  Renata Cristina Penha França  Juliana Ferreira Santos  Marina Marcuschi  Elba Verônica Matoso Maciel Carvalho  Ranilson Souza Bezerra  Luiz Bezerra Carvalho Jr. 《Fish physiology and biochemistry》2014,40(6):1659-1668

Brain cholinesterases from four fish (Arapaima gigas, Colossoma macropomum, Rachycentron canadum and Oreochromis niloticus) were characterized using specific substrates and selective inhibitors. Parameters of catalytic efficiency such as activation energy (AE), k _cat and k _cat/k _m as well as rate enhancements produced by these enzymes were estimated by a method using crude extracts described here. Despite the BChE-like activity, specific substrate kinetic analysis pointed to the existence of only acetylcholinesterase (AChE) in brain of the species studied. Selective inhibition suggests that C. macropomum brain AChE presents atypical activity regarding its behavior in the presence of selective inhibitors. AE data showed that the enzymes increased the rate of reactions up to 10¹² in relation to the uncatalyzed reactions. Zymograms showed the presence of AChE isoforms with molecular weights ranging from 202 to 299 kDa. Values of k _cat and k _cat/k _m were similar to those found in the literature.  相似文献   

Effect of feeding frequency on growth,feed efficiency and nutrient utilization of juvenile flounder (Platichthys flesus luscus)     

Ercan Küçük  İlhan Aydın  Hamza Polat  Orhan Tufan Eroldoğan  Temel Şahin 《Aquaculture International》2014,22(2):723-732

An experiment was conducted to determine the effects of optimal feeding frequency on growth performance, feed efficiency, nutrient utilization and body composition in juvenile flounder. Four feeding frequencies of one (F1), two (F2), three (F3) and four (F4) times a day were evaluated as treatments in triplicate for a period of 60 days. Forty-seven hatchery produced juveniles (2.5 ± 0.7 g) were stocked into 160-L rectangular fiberglass tanks and fed with a commercial diet containing 54 % protein to satiation. At the end of the experiment, the final weight of F1, F2, F3 and F4 were 5.06 ± 0.29, 5.91 ± 0.42, 6.24 ± 0.42 and 6.16 ± 0.46 g, respectively. Growth rates and feed consumption were highest in F3 and lowest in F1. Feed conversion ratios ranged between 0.83 ± 0.04 and 0.90 ± 0.03. There were no significant differences in either moisture or ash content of the fish groups. Protein content decreased with increasing feeding frequency, while lipid content partly increased with increasing feeding frequency. Nitrogen intake and lipid intake were significantly higher in fish fed under F3 and F4 treatment, whereas the nitrogen gain decreased and lipid gain increased with increasing feeding frequency. It is concluded that the flounder juveniles can achieve maximum growth performance and better nutrient utilization when they are fed a given ration two times a day. The findings have practical significance toward establishing an appropriate flounder nursery rearing and will directly benefit the nursery operations.  相似文献   

Measuring development through public policy evaluation? The case of the North Province in New Caledonia     

Jean‐Michel Sourisseau  Pierre‐Marie Bosc  Séverine Bouard  Catherine Gaillard  Jean‐François Bélières  Michel Passouant 《Asia Pacific viewpoint》2014,55(3):355-369

Policies designed for sustainable development are becoming ever more complex and ambiguous. Assessments should thus incorporate development representations and values, rather than only relying on economic and financial normative indicators. This paper proposes a conceptual framework that acknowledges the plurality of the various stakeholders' viewpoints. We suggest that evaluation of grassroots development policies could provide an innovative and more integrative way to measure development by broadening the scope to encompass both livelihood and welfare dimensions. Based on the assessment of a development scheme in New Caledonia, we argue that this cognitive and shared approach could be used to obtain a contextualised measurement of development. Two conditions further strengthen this approach: combining the use of different types of measurement tools, and adopting a rigorous quantitative measurement approach, in line with the collective representations. This promising approach may be applied to gain insight into the ability of implemented policies to address local development choices.  相似文献   

Modulation of neuronal activity and hepatic metabolism by ploidy and l‐carnitine supplement in rainbow trout (Oncorhynchus mykiss)     

B. Nunes  A.F. Miranda  R.O.A. Ozório  F. Gonçalves  J.F.M. Gonçalves  A.T. Correia 《Aquaculture Nutrition》2014,20(3):242-252

l ‐carnitine, a multiphysiological, bioactive and pollution‐free additive, is known to act as a growth‐enhancer and appears to act as an antioxidant compound. However, high dosages may cause detrimental physiological effects to fish. Considering such, a feeding trial was carried out to evaluate the effects of dietary l ‐carnitine content on neuronal activity (acetylcholinesterasic activity), hepatic metabolism (catalase activity) and liver histological markers in both diploid and triploid trout (Oncorhynchus mykiss) juveniles. Fish were hand‐fed for 56 days on three nutritionally identical diets, varying in l ‐carnitine content; unsupplemented diet (15 mg kg^?1) and supplemented (200 or 530 mg kg^?1) diets. Moderate to severe glycogen/lipid depletion was the major liver histopathological disorder observed in all dietary groups. This cause–effect relationship appeared to be dose and time‐dependent, suggesting an important role of l ‐carnitine in the liver metabolism. Moreover, the hepatocite size and nuclear diameter appeared to be larger in l ‐carnitine supplemented groups than in control group. l ‐carnitine caused significant induction of catalase activity and inhibition of AChE. Diploid and triploid trouts showed marked differences in enzymatic activities, reflected by consistently higher values of AChE activities for triploid animals.  相似文献   

Seed germination and viability of herbicide resistant and susceptible Chenopodium album populations after ensiling,digestion by cattle and manure storage     

J Aper  B De Cauwer  S De Roo  M Lourenço  V Fievez  R Bulcke  D Reheul 《Weed Research》2014,54(2):169-177

Chenopodium album became a problem weed in sugar beet production, due to resistance to metamitron, a key herbicide in this crop. Dispersal of the seeds from resistant biotypes may occur due to spread by wind, animals, agricultural machinery or manure. This study examined the effect of ensiling, digestion by cattle and storage in slurry and farmyard manure on the germination and viability of the seeds of one susceptible and three resistant C. album populations. After 4 weeks in a maize silo, seed viability of C. album populations was reduced drastically to 0–5%. Incubation for 24 h in the rumen followed by a post‐ruminal digestion in vitro of intact seeds only resulted in a small reduction in viability in one C. album population. Storage in a slurry cellar for 16 weeks reduced the viability of intact seeds of the C. album populations to 25–60%. Only 0–1% of the seeds remained viable after storage in a farmyard manure heap for 4 weeks. An accelerated ageing experiment showed seed persistence to be population specific and less related to seed weight. Keeping a fresh maize silo closed for at least 4 weeks and heaping farmyard manure are excellent preventive measures to limit the spread of resistant C. album seeds between fields.  相似文献   

Oviposition preference assessment of Diabrotica speciosa (Coleoptera: Chrysomelidae) for different soybean genotypes     

Eduardo Neves Costa  Zulene Antônio Ribeiro  Bruno Henrique Sardinha de Souza  Arlindo Leal Boiça Júnior 《国际虫害防治杂志》2014,60(1):52-58

This study assessed current research methods and applied them to tests of oviposition preference by Diabrotica speciosa (Germar) for different soybean genotypes; the correlation between the number of eggs per plant and leaf intake was evaluated. The experiments were divided into four parts: (i) assessing the preferred oviposition substrate; (ii) standardizing the number of D. speciosa pairs, (iii) evaluating the preferred soybean plant age, and (iv) testing the preference for oviposition on different soybean genotypes, and evaluating its correlation with leaf intake under laboratory conditions. Females of D. speciosa preferred to lay eggs in the soil, with the highest number of eggs laid in the presence of a growing soybean plant. The genotypes PI 227687, DM 339, and PI 274454 were the least preferred varieties for oviposition, while BRSGO 8360 was the most preferred genotype. Egg counts were not correlated with leaf intake, except for the variety IGRA RA 626 RR, which showed positive correlation. Our discoveries may be helpful for second-crop use of resistant genotypes in areas where different crops are cultivated, by reducing the pest density off-season.  相似文献   

Preference and infestation level of Anastrepha fraterculus (Wiedemann, 1830) on fruits of some Psidium guajava L. cultivars and relation to their physicochemical parameters     

Flávia Q. de Oliveira  Arlindo L. Boiça Junior  Maria de Lourdes Z. Costa  Patricia A. Sanches  Julio M. M. Walder  Jacinto de L. Batista 《Phytoparasitica》2014,42(4):475-483

This study aimed to verify the preference and infestation level of Anastrepha fraterculus (Diptera: Tephritidae) [South American fruit fly] in fruits of guava cultivars and to correlate them to variables such as peel coloration, soluble solids and pH of fruit cultivars. The following cultivars were used: Pedro Sato, Paluma, Cascão and Século XXI. The infestation was evaluated in cages, considering two scenarios: no-choice and multiple choice. In both tests, evaluations of the fruit attraction to insects were conducted for a period of 1′, 3′, 5′, 10′, 20′, 30′, 1 h, 2 h, 6 h, 12 h and 24 h. The visit of A. fraterculus on the assayed cultivars in relation to the time was studied by logistic regression. After 10 days, the number of larvae in each fruit was recorded. In the multiple choice test, the visit proportions were significantly higher in the fruits of cvs. Século XXI and Pedro Sato than in those of cvs. Paluma and Cascão. In the no-choice test, the visit proportions were significantly lower in the Paluma fruits. In both tests, the rate of fruit infestation by A. fraterculus did not differ among cvs. Pedro Sato, Paluma and Cascão, whereas the fruits of cv. Século XXI were more infested. The indexes of pH did not interfere with the infestation of A. fraterculus, whereas a high rate of soluble solids and low color angle appear to be crucial for discriminating the fruits of the most susceptible cultivars. Infestation rate of Século XXI fruits displayed significant correlations with: °Brix (r= 0.7078) and color angle (h) (r= –0.9499) of guava fruits under the multiple choice conditions.  相似文献   

Clearance of ingested neonicotinoid pesticide (imidacloprid) in honey bees (Apis mellifera) and bumblebees (Bombus terrestris)     

James E Cresswell  François‐Xavier L Robert  Hannah Florance  Nicholas Smirnoff 《Pest management science》2014,70(2):332-337

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