Coffee ripeness monitoring using a UAV-mounted low-cost multispectral camera     

Rosas  Jorge Tadeu Fim  de Carvalho Pinto  Francisco de Assis  de Queiroz  Daniel Marçal  de Melo Villar  Flora Maria  Magalhães Valente  Domingos Sárvio  Nogueira Martins  Rodrigo 《Precision Agriculture》2022,23(1):300-318

Coffee beverage quality is highly correlated with the degree of fruit ripeness. In this sense, monitoring fruit ripeness is of utmost importance for harvest planning and, especially for obtaining high-quality beverages. Currently, this process is carried out through manual counts of unripe fruits, which is laborious and limited to a few plants within the field. This study aimed at evaluating the potential of a low-cost multispectral camera for coffee ripeness monitoring in the Zona da Mata region of Minas Gerais State, Brazil. For that, five fields of Arabica coffee with distinct characteristics were evaluated. During the coffee ripeness period, four flights were carried using a Phantom 4 Pro quadcopter equipped with a Mapir Survey 3W camera for imagery acquisition. After that, nine vegetation indices (VIs) were obtained. For the same dates, the percentage of unripe fruits was obtained using an irregular grid in all fields. The data was split into two ripeness classes: suitable for harvest (R) with?<?30% of unripe fruits; and not suitable for harvest (U), with?>?30% of unripe fruits. Then, a principal component analysis was used to infer the importance of the VIs to discriminate plants with unripe fruits from those with ripe fruits. The first two principal components explained?>?75% of the variance in the datasets from all coffee fields. The VIs were able to discriminate the ripeness classes (U and R) in most fields; however, their performance was directly influenced by the crop yield and canopy volume.

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Nitrogen and irradiance levels affecting net photosynthesis and growth of young coffee plants (Coffea arabica L.)     

J. I. Fahl  M. L. C. Carelli  J. Vega  A. C. Magalhães 《The Journal of Horticultural Science and Biotechnology》2013,88(1):161-169

Summary

Shoot growth attributes, leaf anatomical changes and net photosynthetic rates were determined in young coffee plants fertilized at high and low levels and subjected to shade or full sunlight. High nitrogen supply increased plant height irrespective of the light level imposed during growth, and promoted a larger leaf area in plants of the shade treatment. Specific leaf weight was 15% higher in plants grown in full sunlight than in shaded plants, at both nitrogen levels. The number of leaves developed on the orthotropic stem increased significantly under full irradiance and high nitrogen availability. Leaves were 11% thicker ih unshaded plants than in shaded ones, because of the increased size of the palisade and spongy parenchyma tissues. More thylakoids per granum and more grana per chloroplast were observed in shade-grown plants, mainly in those given high nitrogen treatment. Total nitrogen content expressed on a leaf-area basis was higher in sun plants supplemented with nitrogen, whereas chlorophyll a and b and protochlorophyll contents increased in shade-grown plants. Net photosynthetic rate in high nitrogen plants reached 7.19 µmol CO₂ m^?2 s^?1 in the full irradiance treatment, and 5.46 µmol CO₂ m^?2 s^?1 in shaded plants. Maximum net photosynthetic rates in the low nitrogen plants were 5.28 and 4.90 µmol CO₂ m^?2 s^?1 in sun and shade plants, respectively. Increased photosynthetic light saturation was observed in high irradiance plants (628 µmol m^?2 s^?1) relative to shade plants (359 µmol m^?2 s^?1) in the high nitrogen treatment. The same pattern was observed in low nitrogen plants. The apparent quantum yield of shade acclimated plants was 14% higher than in those grown in full sunlight. Our results indicate that coffee may be classified as a facultative shade species, exhibiting features of sun adapted plants coupled with shade acclimation attributes, this fairly high adaptive capacity to shade:sun transition being strongly influenced by the level of nitrogen nutrition given to the plants.  相似文献   

Dietary protein requirement of zebra sea bream (Diplodus cervinus,Lowe 1838) juveniles          下载免费PDF全文

F. Coutinho  H. Peres  C. Castro  A. Pérez‐Jiménez  R. Magalhães  P. Pousão‐Ferreira  A. Oliva‐Teles 《Aquaculture Nutrition》2016,22(2):465-471

A 14 weeks growth trial was performed to estimate the protein requirement for growth and maintenance of zebra sea bream (Diplodus cervinus) juveniles. For that purpose, nine isolipidic diets were formulated to contain increasing protein levels (from 50 to 550 g kg^?1) at the expense of carbohydrate. Each diet was assigned to duplicate groups of 20 fish, with an average body weight of 7.7 g. Feed efficiency improved with dietary protein up to 400 g kg^?1, no further differences being noticed at higher protein levels. Fish fed the 50 g kg^?1 protein diet lost weight during the trial. In the other groups, weight gain improved as dietary protein increased up to 350–400 g kg^?1. Fish fed diets with 250 g kg^?1 protein or lower had lower whole‐body protein content than the other groups. A curvilinear‐plateau model was used to adjust weight gain and protein gain (g kg ABW^?1 day^?1) to dietary protein levels. Based on that model, the optimum dietary protein requirement for maximum weight gain was estimated to be 437.6 g kg^?1 and for maximum protein gain 461.9 g kg^?1, corresponding to a protein intake of 7.63 g kg ABW^?1 day^?1. Protein requirement for maintenance was estimated to be 1.01 g kg ABW^?1 day^?1.  相似文献   

Expression levels of mRNA-encoding PDGF receptors in goat ovaries and the influence of PDGF on the in vitro development of caprine pre-antral follicles     

Brito IR  Lima IM  Saraiva MV  Silva CM  Magalhães-Padilha DM  Araújo VR  Barreto Luz V  Barbalho Silva AW  Campello CC  Silva JR  Figueiredo JR 《Reproduction in domestic animals》2012,47(5):695-703

The aims of this study were to investigate the expression levels of mRNA for platelet-derived growth factor (PDGF) receptors (PDGFR-α and -β) in caprine follicles at different developmental stages and to evaluate the influence of PDGF on the in vitro development of pre-antral follicles. For this, goat primordial, primary and secondary follicles, as well as small (1-3 mm) and large (3-6 mm) antral follicles, were obtained, and PDGFR-α and -β mRNA levels were quantified by real-time PCR. Furthermore, pre-antral follicles (≥ 200 μm) were isolated from goat ovaries and cultured for 18 days in α- minimum essential medium supplemented with PDGF at 50 or 100 ng/ml, containing or not FSH. Real-time PCR showed highest PDGFR-α mRNA levels in secondary follicles, while PDGFR-β mRNA levels were highest in primary follicles onwards. Both receptors showed higher mRNA levels in granulosa/theca cells from small and large antral follicles than in their corresponding cumulus-oocyte complexes. In culture, the percentage of antrum formation was significantly higher in 100 ng/ml PDGF compared with the same PDGF concentration associated with FSH. After 18 days, PDGF in both concentrations associated with FSH promoted follicular growth significantly higher than the control. Moreover, the addition of FSH to 50 ng/ml PDGF positively influenced the follicular growth when compared with the same PDGF concentration in the absence of FSH. In conclusion, PDGF is important for early goat folliculogenesis, because the presence of PDGFR-α and -β mRNA was detected in all follicular categories, and PDGF associated with FSH stimulated the growth of goat pre-antral follicles isolated and cultured in vitro.  相似文献   

Factors associated with infection by Neospora caninum in dogs in Brazil     

Sicupira PM  de Magalhães VC  Galvão Gda S  Pereira MJ  Gondim LF  Munhoz AD 《Veterinary parasitology》2012,185(2-4):305-308

From August 2006 to 2008, 411 dogs in northeastern Brazil were evaluated for seropositivity to Neospora caninum. The dogs were clinically examined, and their owners were interviewed about the conditions in which the animals were maintained in order to assess the factors associated with infection by this parasite. A serum sample was taken from each dog for serological examination in an indirect fluorescent antibody test for N. caninum. The Yates' Chi-square test or Fisher's exact test was used to select the variables for the multivariate logistic regression model. Seropositivity was detected in 9.26% of dogs. The seropositivity rates of dogs from different environments were 2.6% (4/156) in urban areas, 13.1% (28/214) in peri-urban areas, and 14.6% (6/41) in rural areas. Factors associated with seropositivity for N. caninum were the following: contact with other dogs, access to food outside the home and residing in the peri-urban or rural environments (p<0.05). Results of this study confirm that dogs in urban, rural and peri-urban areas of northeastern Brazil are exposed to N. caninum. Control measures to prevent infection of dogs in the studied region should be focused primarily on preventing access to potential sources of infection, which include environments with other dogs, bovines, and other small intermediate hosts, such as birds and rodents.  相似文献   

Linking like with like: optimising connectivity between environmentally-similar habitats     

Diogo Alagador  Maria Trivi?o  Jorge Orestes Cerdeira  Raul Brás  Mar Cabeza  Miguel Bastos Araújo 《Landscape Ecology》2012,27(2):291-301

Habitat fragmentation is one of the greatest threats to biodiversity. To minimise the effect of fragmentation on biodiversity, connectivity between otherwise isolated habitats should be promoted. However, the identification of linkages favouring connectivity is not trivial. Firstly, they compete with other land uses, so they need to be cost-efficient. Secondly, linkages for one species might be barriers for others, so they should effectively account for distinct mobility requirements. Thirdly, detailed information on the auto-ecology of most of the species is lacking, so linkages need being defined based on surrogates. In order to address these challenges we develop a framework that (a) identifies environmentally-similar habitats; (b) identifies environmental barriers (i.e., regions with a very distinct environment from the areas to be linked), and; (c) determines cost-efficient linkages between environmentally-similar habitats, free from environmental barriers. The assumption is that species with similar ecological requirements occupy the same environments, so environmental similarity provides a rationale for the identification of the areas that need to be linked. A variant of the classical minimum Steiner tree problem in graphs is used to address c). We present a heuristic for this problem that is capable of handling large datasets. To illustrate the framework we identify linkages between environmentally-similar protected areas in the Iberian Peninsula. The Natura 2000 network is used as a positive ‘attractor’ of links while the human footprint is used as ‘repellent’ of links. We compare the outcomes of our approach with cost-efficient networks linking protected areas that disregard the effect of environmental barriers. As expected, the latter achieved a smaller area covered with linkages, but with barriers that can significantly reduce the permeability of the landscape for the dispersal of some species.  相似文献   

Structural organization of the glnBA region of the Azospirillum brasilense genome     

Patrícia Castellen  Roseli Wassem  Rose Adele Monteiro  Leonardo Magalhães Cruz  Maria Berenice R. Steffens  Leda S. Chubatsu  Emanuel Maltempi de Souza  Fabio de Oliveira Pedrosa 《European Journal of Soil Biology》2009,45(1):100-105

The Azospirillum brasilense genomic region containing the glnBA genes was previously cloned in a broad-host range plasmid named pAB441. Previous results from our laboratory have shown that A. brasilense spontaneous mutants resistant to ethylenediamine carrying this plasmid had no nitrogenase activity. The 19 kb insert of this plasmid was fully sequenced and no other gene potentially involved with nitrogen fixation was identified, nor any gene potentially involved in the regulation of nif genes expression. Apart from glnBA, this region contains several genes involved with different functions: assisting protein folding and degradation, DNA organization, electron transport and energy conversion and conserved hypothetical proteins of unknown function. Since previous data on the literature showed that mutation of clpX gene of A. brasilense resulted in higher nitrogenase activity, we hypothesize that higher expression of the clpX gene from the plasmid pAB441 may be involved with Nif^? phenotype of the A. brasilense mutant strains.  相似文献   

Influence of multiple- and single-species infestations on herbivore-induced cotton volatiles and <Emphasis Type="Italic">Anthonomus grandis</Emphasis> behaviour     

Diego Martins Magalhães  Miguel Borges  Raúl Alberto Laumann  Maria Carolina Blassioli Moraes 《Journal of pest science》2018,91(3):1019-1032

Plants interact with multiple organisms throughout their life cycle. As a result, they are commonly attacked by multiple species of herbivores, leading to the induction of plant defence systems. Herbivore-induced plant volatiles (HIPVs) play an important role in the interaction between community members and can be used to manipulate insect pest behaviour, being a valuable tool in integrated pest management strategy. In this study, the interaction of two chewing insects, the boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, and of one piercing-sucking insect, the Neotropical brown stinkbug, Euschistus heros, was evaluated for the induction of volatile compounds in cotton under single- and multiple-species attacks. As a control, the emissions of undamaged plants were also measured. In addition, the effect of HIPVs on boll weevil behaviour was also assessed. Qualitatively, single- and multiple-species herbivory induced a similar volatile blend. There was, however, a difference in the amount and proportion of compounds emitted. Plants infested with E. heros emitted a blend of volatiles more similar to that of the undamaged control compared to the other herbivore-induced treatments. The plant volatiles emitted due to simultaneous multiple-species herbivory were induced faster than volatiles emitted by sequential herbivory events, indicating different induction mechanisms depending on the attack configuration. In addition, cotton volatiles induced by an individual attack of A. grandis were attractive to conspecifics, as were the volatiles induced by multiple-species herbivory in both simultaneous and sequential attacks. The use of cotton HIPVs, both under multiple- and single-species attack, can be used for the development of alternative methods for semiochemical-based weevil management, e.g., enrichment of aggregation pheromone traps with plant volatiles.  相似文献   

Determinants of mild-to-moderate malnutrition in preschoolers in an urban area of Northeastern Brazil: a hierarchical approach     

Oliveira Assis AM  Barreto ML  Magalhães de Oliveira LP  de Oliveira VA  da Silva Prado M  da Silva Gomes GS  Conceição Pinheiro SM  Dos Santos NS  Ribeiro da Silva Rde C  Ramos Sampaio L  Pacheco Santos LM 《Public health nutrition》2008,11(4):387-394

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Modeling and design of an injection dosing system for site-specific management using liquid fertilizer     

da Silva  M. J.  Magalhães  P. S. Graziano 《Precision Agriculture》2019,20(4):649-662

Precision Agriculture - A variable rate of fertilizer according to plant demand and placement (50–100&nbsp;mm deep) beside roots are essential principles for improving nitrogen use...  相似文献