771 research outputs found
Screening for Drought Tolerance in Thirty Three Taro Cultivars
Taro [Colocasia esculenta (L.) Schott] is a root crop which is an important staple food in many regions of the world, producing 10.5 million tonnes on 1.4 million hectares a year. The crop is cultivated in wet (rain fed) or irrigated conditions, requiring on average 2,500 mm water per year, and in many countries it is cultivated in flooded plots. It is estimated that taro production could decrease by 40% as a result of the increase in drought and other severe events. In this work, thirty three accessions, including local cultivars, selected and hybrid lines were submitted to long duration drought stress and screened for tolerance. Twelve physiological, morphological and agronomic traits were measured at harvest, and subject to multivariate analysis. Stress indices, Water Use Efficiency and Factorial Analysis were useful for discriminating accessions regarding drought tolerance and yield stability, and drought tolerant and susceptible cultivars were identified. Our results confirm that different taro cultivars have different drought avoidance and tolerance strategies to cope with water scarcity. Better yield performers minimised biomass and canopy loss, while tolerance was observed in cultivars that presented low potential yield, but efficiently transferred resources to enhance corm formation. Among the 33 accessions, two local cultivars showed high yield stability and could be considered as suitable parents for breeding programs, while two others are well adapted to drought, but with overall low yield potential
Quasivariational solutions for first order quasilinear equations with gradient constraint
We prove the existence of solutions for an evolution quasi-variational
inequality with a first order quasilinear operator and a variable convex set,
which is characterized by a constraint on the absolute value of the gradient
that depends on the solution itself. The only required assumption on the
nonlinearity of this constraint is its continuity and positivity. The method
relies on an appropriate parabolic regularization and suitable {\em a priori}
estimates. We obtain also the existence of stationary solutions, by studying
the asymptotic behaviour in time. In the variational case, corresponding to a
constraint independent of the solution, we also give uniqueness results
Análise Espacial Da Produtividade De Serapilheira Em Uma Mata De Galeria
The gallery forests have great genetic diversity and important ecological functions, such as protecting the headwaters, controlling erosion, and functioning as buffer zones and filtering chemicals. Litterfall, which can be used as an indicator of ecological productivity, is widely collected using litter traps that are randomly distributed in a forest plot. However, vegetation distribution may present spatial dependence, thus the yield of the litterfall can be mapped using geostatistical techniques allowing the delineation of management zones. Therefore, the objective of this study was to evaluate the efficiency of geostatistical methods using the zoning management productivity of litterfall on a gallery forest in central Brazil. The study was conducted on the gallery forest along the ‘Lava-pés’ stream in Goiás State, Brazil where the experimental site (3 ha) was structured in a grid of 60 litterfall traps, each of 0.33 m2 held 0.65 m above the ground, georeferenced, spaced at 32 x 32 m intervals. Litterfall was monthly collected from December 2011 to November 2012. All litterfall samples were manually separated into three fractions: leaves (LE), branch bark (BB), and reproductive parts (RP) and they were expressed in kg ha-1. Statistical analyses consisted of data description and geostatistics. The litterfall of for LE and total showed strong spatial dependence. The BB and RP showed pure nugget effect. The total litterfall maps obtained by the Kriging interpolation method indicated zones in the map ranging from 900 to 10,900 kg ha-1 per yr. The kriging interpolation technique delineate management zones of productivity in the gallery forest litterfall studied, which allowed the specific forest management of litterfall. © 2016, Universidade Federal de Santa Maria. All Rights Reserved.26248950
Potential for macro and micronutrients extraction from tomato plants with different soil water stresses
Different tomato cultivars may present differentiated water needs, making it
indispensable to study water demand. Thus, the objective of this work was to evaluate the
influence of six water stresses in the soil on the extraction potential of macro and micronutrients
in the aerial part of tomato in vegetative stage, cultivar ‘Dominador’ F1, under protected
cultivation and drip. The experiment was installed in a greenhouse with a randomized block
design with four replications. The treatments consisted of six soil water stresses as indicative of
the time of irrigation. The preset stresses were 20, 45, 70, 95, 120 and 145 kPa at 20 cm depth.
At 140 days after transplanting, the variables evaluated were: the macro and micronutrient content
of shoots. The results showed that to obtain higher levels of macro (P and S) and micronutrients
(B and Cu) of the total aerial part of the ‘Dominador’ tomato plant F1, it was obtained at a voltage
of 20 kPa, and its value was reduced linearly with the increase of the water tension in the soil
Anti-Inflammatory Effect of Dexamethasone Controlled Released From Anterior Suprachoroidal Polyurethane Implants on Endotoxin-Induced Uveitis in Rats.
Targeted drug delivery to the ocular tissues remains a challenge. Biodegradable intraocular implants allow prolonged controlled release of drugs directly into the eye. In this study, we evaluated an anterior suprachoroidal polyurethane implant containing dexamethasone polyurethane dispersions (DX-PUD) as a drug delivery system in the rat model of endotoxin-induced uveitis (EIU).
In vitro drug release was studied using PUD implants containing 8%, 20%, and 30% (wt/wt) DX. Cytotoxicity of the degradation products of DX-PUD was assessed on human ARPE-19 cells using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) test. Short-term ocular biocompatibility of suprachoroidal DX-PUD implants was evaluated in normal rat eyes. Endotoxin-induced uveitis was then induced in rat eyes preimplanted with DX-PUD. Clinical examination was performed at 24 hours; eyes were used to assess inflammatory cell infiltration and macrophage/microglial activation. Cytokine and chemokine expression in the iris/ciliary body and in the retina was investigated using quantitative PCR. Feasibility of anterior suprachoroidal PUD implantation was also tested using postmortem human eyes.
A burst release was followed by a sustained controlled release of DX from PUD implants. By-products of the DX-PUD were not toxic to human ARPE-19 cells or to rat ocular tissues. Dexamethasone-PUD implants prevented EIU in rat eyes, reducing inflammatory cell infiltration and inhibiting macrophage/microglial activation. Dexamethasone-PUD downregulated proinflammatory cytokines/chemokines (IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]) and inducible nitric oxide synthase (iNOS) and upregulated IL-10 anti-inflammatory cytokine. Polyurethane dispersion was successfully implanted into postmortem human eyes.
Dexamethasone-PUD implanted in the anterior suprachoroidal space may be of interest in the treatment of intraocular inflammation
Antiproliferative activity of synthetic fatty acid amides from renewable resources
AbstractIn the work, the in vitro antiproliferative activity of a series of synthetic fatty acid amides were investigated in seven cancer cell lines. The study revealed that most of the compounds showed antiproliferative activity against tested tumor cell lines, mainly on human glioma cells (U251) and human ovarian cancer cells with a multiple drug-resistant phenotype (NCI-ADR/RES). In addition, the fatty methyl benzylamide derived from ricinoleic acid (with the fatty acid obtained from castor oil, a renewable resource) showed a high selectivity with potent growth inhibition and cell death for the glioma cell line—the most aggressive CNS cancer
Multicenter, International Study of MIC/ MEC Distributions for definition of epidemiological cutoff values for sporothrix species identified by molecular methods
Clinical and Laboratory Standards Institute (CLSI) conditions for testing the susceptibilities of pathogenic Sporothrix species to antifungal agents are based on a collaborative study that evaluated five clinically relevant isolates of Sporothrix schenckii sensu lato and some antifungal agents. With the advent of molecular identification, there are two basic needs: to confirm the suitability of these testing conditions for all agents and Sporothrix species and to establish species-specific epidemiologic cutoff values (ECVs) or breakpoints (BPs) for the species. We collected available CLSI MICs/minimal effective concentrations (MECs) of amphotericin B, five triazoles, terbinafine, flucytosine, and caspofungin for 301 Sporothrix schenckii sensu stricto, 486 S. brasiliensis, 75 S. globosa, and 13 S. mexicana molecularly identified isolates. Data were obtained in 17 independent laboratories (Australia, Europe, India, South Africa, and South and North America) using conidial inoculum suspensions and 48 to 72 h of incubation at 35°C. Sufficient and suitable data (modal MICs within 2-fold concentrations) allowed the proposal of the following ECVs for S. schenckii and S. brasiliensis, respectively: amphotericin B, 4 and 4 /ml; itraconazole, 2 and 2 μg/ml; posaconazole, 2 and 2 μg/ml; and voriconazole, 64 and 32 μg/ml. Ketoconazole and terbinafine ECVs for S. brasiliensis were 2 and 0.12 μg/ml, respectively. Insufficient or unsuitable data precluded the calculation of ketoconazole and terbinafine (or any other antifungal agent) ECVs for S. schenckii, as well as ECVs for S. globosa and S. mexicana. These ECVs could aid the clinician in identifying potentially resistant isolates (non-wild type) less likely to respond to therapy.A. Espinel-Ingroff, D. P. B. Abreu, R. Almeida-Paes, R. S. N. Brilhante, A. Chakrabarti, A. Chowdhary, F. Hagen, S. Córdoba, G. M. Gonzalez, N. P. Govender, J. Guarro, E. M. Johnson, S. E. Kidd, S. A. Pereira, A. M. Rodrigues, S. Rozental, M. W. Szeszs, R. Ballesté Alaniz, A. Bonifaz, L. X. Bonfietti, L. P. Borba-Santos, J. Capilla, A. L. Colombo, M. Dolande, M. G. Isla, M. S. C. Melhem, A. C. Mesa-Arango, M. M. E. Oliveira, M. M. Panizo, Z. Pires de Camargo, R. M. Zancope-Oliveira, J. F. Meis, J. Turnidge
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