Invasive dynamics of the crayfish Procambarus clarkii (Girard, 1852) in the international section of the River Minho (NW of the Iberian Peninsula)     

Ronaldo Sousa  Fabiana E. P. Freitas  Micaela Mota  António J. A. Nogueira  Carlos Antunes 《水产资源保护:海洋与淡水生态系统》2013,23(5):656-666

Economic feasibility for producing Imperial Zebra pleco (Hypancistrus zebra) in recirculating aquaculture systems: An alternative for a critically endangered ornamental fish     

Danilo Araujo Soares Pereira  Marcelo Barbosa Henriques 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):428-448

Abstract

The L46 (Hypancistrus zebra) stands out as one of the most valuable Amazonian species in the international market for ornamental fish and faces a notable problem: the risk of extinction versus the demand for new specimens for aquariums. Considering that breeding in captivity can be a conservational tool for aquatic species and an alternative source for generating income, the objective of the present paper was to verify the economic feasibility of producing H. zebra in recirculation aquaculture systems (RAS), in different scenarios of rearing: residential breeding (S1), mid-size store production (S2) and large-scale production as a supplier (S3). The main profitability indicators used were: net present value (NPV), internal rate of return (IRR) and payback period (PP). The selling price per unit was fixed in US$260.15 (S1/S2) and US$156.09 (S3). The largest investments were made with the acquisition of broodstocks (S1/S2) and property (S3), while the highest costs were with labor (S2/S3) and taxes (S1). Only S1 demonstrated economic profitability (NPV 8.50%?=?US$28,187.85; IRR?=?74.71%; PP?=?1.80?years). Conclusion: the production in this study appeared to be profitable on smaller scales, however the profitability of large-scale production depends upon reducing expenses and increasing the selling price.  相似文献   

Glyphosate sustainability in South American cropping systems   总被引：1，自引：0，他引：1  

Christoffoleti PJ  Galli AJ  Carvalho SJ  Moreira MS  Nicolai M  Foloni LL  Martins BA  Ribeiro DN 《Pest management science》2008,64(4):422-427

South America represents about 12% of the global land area, and Brazil roughly corresponds to 47% of that. The major sustainable agricultural system in South America is based on a no-tillage cropping system, which is a worldwide adopted agricultural conservation system. Societal benefits of conservation systems in agriculture include greater use of conservation tillage, which reduces soil erosion and associated loading of pesticides, nutrients and sediments into the environment. However, overreliance on glyphosate and simpler cropping systems has resulted in the selection of tolerant weed species through weed shifts (WSs) and evolution of herbicide-resistant weed (HRW) biotypes to glyphosate. It is a challenge in South America to design herbicide- and non-herbicide-based strategies that effectively delay and/or manage evolution of HRWs and WSs to weeds tolerant to glyphosate in cropping systems based on recurrent glyphosate application, such as those used with glyphosate-resistant soybeans. The objectives of this paper are (i) to provide an overview of some factors that influence WSs and HRWs to glyphosate in South America, especially in Brazil, Argentina and Paraguay soybean cropped areas; (ii) to discuss the viability of using crop rotation and/or cover crops that might be integrated with forage crops in an economically and environmentally sustainable system; and (iii) to summarize the results of a survey of the perceptions of Brazilian farmers to problems with WSs and HRWs to glyphosate, and the level of adoption of good agricultural practices in order to prevent or manage it.  相似文献   

Esparto wool as reinforcement in hybrid polyurethane composite foams     

Marcelo Antunes  Álvaro CanoLaia Haurie  José Ignacio Velasco 《Industrial Crops and Products》2011,34(3):1641-1648

In the present work polyurethane foams containing variable concentrations of nano-sized clay and esparto wool were prepared and studied, with the objective of developing new multi-scalar rigid foams. The addition of montmorillonite clay favoured foaming and the formation of finer and homogeneous cellular structures, resulting in foams with compressive elastic moduli and collapse stresses lower than that of the polyurethane foams. Nevertheless, a comparative analysis versus the foams’ relative density demonstrated that both properties follow one single trend for the two materials. The combination of esparto and montmorillonite further reduced the cell size of foams, at the same time promoting higher open cell contents, resulting in the foams with the lowest mechanical properties. Although no important differences in thermal conductivity were found with adding montmorillonite, its value decreasing with reducing the relative density, the incorporation of esparto led to higher thermal conductivities, independently of the relative density. The combination of esparto and montmorillonite resulted in foams with thermal conductivities halfway between the esparto-reinforced and the montmorillonite-reinforced foams, related to a higher open cell content.  相似文献   

New invasion of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> Mediterranean species in Brazil associated to ornamental plants     

Letícia Aparecida de Moraes  Julio Massaharu Marubayashi  Valdir Atsushi Yuki  Murad Ghanim  Vinicius Henrique Bello  Bruno Rossitto De Marchi  Leonardo da Fonseca Barbosa  Laura M. Boykin  Renate Krause-Sakate  Marcelo Agenor Pavan 《Phytoparasitica》2017,45(4):517-525

In Brazil, the first major invasion event of Bemisia tabaci was that of Middle East–Asia Minor 1 (MEAM1) species, formerly termed as B biotype, which commenced in the 1990s mainly by ornamental plants in São Paulo State. More than two decades after this invasion, the presence of the Mediterranean (MED) species of B. tabaci, formerly Q biotype, was reported in Rio Grande do Sul, the southernmost State of Brazil, and now in São Paulo and Paraná States, in southeastern Brazil. Specimens of whiteflies collected from commercial begonia, hydrangea, petunia and poinsettia greenhouses in São Paulo, and also from begonias and poinsettias collected in flower shops in Paraná, were all identified as belonging to MED species. Furthermore, the secondary endosymbionts Arsenophonus, Hamiltonella and Rickettsia of MED from São Paulo and Paraná were detected by PCR and their presence confirmed by sequencing and FISH analysis, and those results differed from MED detected in Rio Grande do Sul that harbored only Hamiltonella and Cardinium. Our results suggest a new MED invasion into Brazil and is associated with ornamental plants. The two MED populations are genetically different and suggest that they are separate invasions.  相似文献   

Cardiopulmonary effects of reverse Trendelenburg position at 5° and 10° in sevoflurane-anesthetized steers     

Marcelo A. Araújo  Maurício Deschk  Juliana T. Wagatsuma  Beatriz P. Floriano  Carlos E. Siqueira  Valéria NLS. Oliva  Paulo SP. Santos 《Veterinary anaesthesia and analgesia》2017,44(4):854-864

Objective

To assess the cardiopulmonary effects caused by reverse Trendelenburg position (RTP) at 5° and 10° in sevoflurane-anesthetized yearling steers.

Study design

Prospective, experimental study.

Animals

Eight Holstein steers aged (mean ± standard deviation) 12 ± 2 months and weighing 145 ± 26 kg.

Methods

In the first phase of the study, the individual minimum alveolar concentration (MAC) of sevoflurane was determined using electrical stimulation. In the second phase, the effects of RTP were assessed. The animals were anesthetized on three separate events separated by ≥7 days in an incomplete crossover design: control treatment using a table without tilt (RTP0); treatment with the table at 5° RTP (RTP5) and table tilted 10° RTP (RTP10). Subjects were physically restrained in dorsal recumbency on the table, which was already tilted according to each treatment. Anesthesia was induced with sevoflurane at 8% in 5 L minute^–1 oxygen via face mask followed by maintenance with sevoflurane at 1.3 MAC and spontaneous breathing. Cardiopulmonary variables were obtained immediately after instrumentation (T₀) and then after 30, 60, 120 and 180 minutes (T₃₀, T₆₀, T₁₂₀ and T₁₈₀, respectively).

Results

The mean sevoflurane MAC for the eight steers was 2.12 ± 0.31%. Cardiac output was lower at all time points and the systemic vascular resistance index was higher at T₁₂₀ and T₁₈₀ in RTP10 compared with RTP0. Oxygen consumption was lower at T₀ and at T₁₈₀ in RTP10 compared with RTP0 and at all time points except T₃₀ compared with RTP5. Oxygen extraction was lower at T₀ in RTP10 compared with RTP0 and RTP5, and at T₆₀ and T₁₈₀ compared with RTP5.

Conclusions and clinical relevance

RTP 5° and 10° did not improve ventilatory and oxygenation variables in sevoflurane-anesthetized steers when compared with no tilt, however the cardiovascular variables were adversely affected in RTP10.  相似文献   

Hydraulic Retention Time Influence on Improving Flocculation in the Activated Sludge Processes Through Polyelectrolytes     

Cristina E. Almeida-Naranjo  Patricio J. Espinoza-Montero  Marcelo I. Muñoz-Rodríguez  Cristina A. Villamar-Ayala 《Water, air, and soil pollution》2017,228(7):253

Hydraulic retention time (HRT) influence improving sludge flocculation with adding the polyelectrolytes (non-ionic, anionic, and cationic) was studied on an activated sludge (AS) system fed with synthetic domestic wastewater (SDW), dairy industry wastewater (DIW), and caramel industry wastewater (CIW). The sludge volumetric index, food/microorganism ratio (F/M), and mixed liquor volatile suspended solids at different HRTs (6, 8 and 10 h) were monitored on an experimental model. Results showed that both SDW and IW had the best sludge flocculation conditions at 8 h and 100 mL of non-ionic polyelectrolyte (0.2 mg L^?1). In addition, this phenomenon reached the organic matter removal efficiencies of 95.9, 95.7, and 94.2% for SDW, DIW, and CIW, respectively. Therefore, optimum HRT increased the organic matter removal efficiencies by 10%, sludge concentration by 37% (22–55%), and F/M ratio by 70%. Moreover, the polyelectrolytes used in AS improved the sludge flocculation by 2.9 times.  相似文献   

Individual leaf area estimations of a dioecious tropical tree species <Emphasis Type="Italic">Carpotroche brasiliensis</Emphasis> (Raddi) A. Gray,Achariaceae     

Ediófila Brito-Rocha  Letícia dos Anjos  Ana Cristina Schilling  Ândrea Carla Dalmolin  Marcelo S. Mielke 《Agroforestry Systems》2017,91(1):9-15

Carpotroche brasiliensis is a dioecious tree species native of the Brazilian Atlantic rainforest. Due to medical and industrial use of the oil extracted from its seeds, C. brasiliensis has a great potential for cultivation as non-timber forest product in agroforestry systems. This study was conducted with the objective to analyze the leaf dimensions of male and female adult trees and seedlings of C. brasiliensis. Two hypotheses were tested: (a) leaf dimensions do not differ between male and female adult genotypes; and (b) it is possible to develop single regression models for predicting leaf area (LA) from dimensional variables encompassing male and female adult genotypes and seedlings. LA, leaf length (L) and maximum leaf width (W) were measured in leaves collected from seven male and seven female adult genotypes and three seedling lots. The feasibility of using a single model for leaves of males and females, and seedlings and adults, was tested by analysis of covariance (ANCOVA). The prediction errors (PE) for each of the regression models were calculated from the cross-validation method. The average values of L, W and LA were, respectively, 136, 142 and 457 % higher in adults than in seedlings, and the average values of leaf shapes (L:W) of seedlings were intermediate between the average values of L:W of adult males and females. The average values of L did not differ between adult males and females, but significant differences were observed between males and females for W, LA and L:W (both p < 0.01, nested ANOVA). The mean L:W values of adult males and females, and seedlings, indicate that leaf shape should be used as a criterion for sex differentiation in this species. It was not possible to develop single models encompassing adult males and females, and seedlings; but high accurate predictive models of LA from L × W measurements were developed for adult males (R² = 0.98, PE = 0.69, n = 350), adult females (R² = 0.98, PE = 0.01, n = 350), and seedlings (R² = 0.99, PE = 6.80, n = 150).  相似文献   

Liming as an ameliorator of copper toxicity in black oat (Avena strigosa Schreb.)     

Vítor Gabriel Ambrosini  Daniel José Rosa  Alex Basso  Marcelo Borghezan  Rosete Pescador  Alcione Miotto 《Journal of plant nutrition》2017,40(3):404-416

This study aimed to assess the effect of liming as an ameliorator of copper (Cu) toxicity in black oats (Avena strigosa Schreb.) grown in soil with a sandy texture. The treatments were soil supplementation with increasing doses of lime (0.0, 0.5 and 1.0 g kg^?1) and two of Cu (0 and 50 mg kg^?1). Pre-germinated black oat seeds were sown for 30 days in the soil, subsequently, the plant height, root and shoot dry mass and concentration of total chlorophyll, chlorophylls a and b, carotenoids and total soluble carbohydrates and starch were analyzed. The dose of 50 mg kg^?1 soil Cu caused a toxic effect on black oat plant growth and development, affected the internal distribution of nutrients, decreased the leaf chlorophyll concentration and increased the leaf concentration of total soluble carbohydrates and starch. Increasing lime doses ameliorated the toxic effects of Cu.  相似文献   

Inheritance of coffee leaf rust resistance and identification of AFLP markers linked to the resistance gene     

Giovani Greigh de Brito  Eveline Teixeira Caixeta  Ana Paula Gallina  Eunize Maciel Zambolim  Laércio Zambolim  Valdir Diola  Marcelo Elhers Loureiro 《Euphytica》2010,173(2):255-264

The most important disease of Coffea arabica is coffee leaf rust caused by the fungus Hemileia vastatrix. The purpose of this study was to characterize the inheritance of coffee resistance gene(s) to race II of this pathogen and to identify and map molecular markers linked to this trait. Different populations were used: F₂ (160 plants), BCr (20), and BCs (135), derived from a cross between the resistant genotype Híbrido de Timor UFV 427-15 and the susceptible cultivar Catuaí Amarelo UFV 2143-236 (IAC 30). The segregation analysis showed that the resistance of Híbrido de Timor to race II of the H. vastatrix is conferred by a single dominant gene. The amplification of 176 AFLP (Amplified fragment length polymorphism) primer combinations using bulked segregant analysis (BSA) allowed the identification of three molecular markers linked to the resistance gene. Genetic mapping of these three markers in the F₂ population indicated that they are distributed on both sides, flanking the resistance gene. The markers E.CTC/M.TTT405 and E.CGT/M.TGT300 were found linked to the resistance gene at 8.69 cM (LOD 18.91) and 25.10 cM (LOD 5.37), respectively, while E.CCT/M.TTC230 was localized on the other side of the gene, at 20.50 cM (LOD 6.15). These markers are the first rust resistance markers identified in Híbrido de Timor and can be useful for marker assisted selection in coffee breeding programs.  相似文献