43 resultados para Principle of alternative possibilities
em Scielo Saúde Pública - SP
Resumo:
Assassin bugs (Reduviidae) are voracious insects that prey on other arthropods. Recent evidences have pointed out that these predators also feed on plant derived substances in rare opportunities. The present study describes the feeding behavior of the reduviid Atopozelus opsimus on extrafloral nectaries of Inga vera (Fabaceae) in a Neotropical savanna area. It was investigated if the insects feed more frequently of extrafloral nectar or prey, and if individuals of different stages of development vary according to feeding behavior. Notably, the results suggest that the diet of all instars and adults consist mainly of extrafloral nectar (N = 1013), in detriment of captured prey ingestion (N = 18). Also, there was no variation on feeding behavior and life stage.
Resumo:
The current high price of potassium chloride and the dependence of Brazil on imported materials to supply the domestic demand call for studies evaluating the efficiency of alternative sources of nutrients. The aim of this work was to evaluate the effect of silicate rock powder and a manganese mining by-product, and secondary materials originated from these two materials, on soil chemical properties and on brachiaria production. This greenhouse experiment was conducted in pots with 5 kg of soil (Latossolo Vermelho-Amarelo distrófico - Oxisol). The alternative nutrient sources were: verdete, verdete treated with NH4OH, phonolite, ultramafic rock, mining waste and the proportion of 75 % of these K fertilizers and 25 % lime. Mixtures containing 25 % of lime were heated at 800 ºC for 1 h. These sources were applied at rates of 0, 150, 300, 450 and 600 kg ha-1 K2O, and incubated for 45 days. The mixtures of heated silicate rocks with lime promoted higher increases in soil pH in decreasing order: ultramafic rock>verdete>phonolite>mining waste. Applying the mining waste-lime mixture increased soil exchangeable K, and available P when ultramafic rock was incorporated. When ultramafic rock was applied, the release of Ca2+ increased significantly. Mining subproduct released the highest amount of Zn2+ and Mn2+ to the soil. The application of alternative sources of K, with variable chemical composition, altered the nutrient availability and soil chemical properties, improving mainly plant development and K plant uptake, and are important nutrient sources.
Resumo:
ABSTRACT When Hume, in the Treatise on Human Nature, began his examination of the relation of cause and effect, in particular, of the idea of necessary connection which is its essential constituent, he identified two preliminary questions that should guide his research: (1) For what reason we pronounce it necessary that every thing whose existence has a beginning should also have a cause and (2) Why we conclude that such particular causes must necessarily have such particular effects? (1.3.2, 14-15) Hume observes that our belief in these principles can result neither from an intuitive grasp of their truth nor from a reasoning that could establish them by demonstrative means. In particular, with respect to the first, Hume examines and rejects some arguments with which Locke, Hobbes and Clarke tried to demonstrate it, and suggests, by exclusion, that the belief that we place on it can only come from experience. Somewhat surprisingly, however, Hume does not proceed to show how that derivation of experience could be made, but proposes instead to move directly to an examination of the second principle, saying that, "perhaps, be found in the end, that the same answer will serve for both questions" (1.3.3, 9). Hume's answer to the second question is well known, but the first question is never answered in the rest of the Treatise, and it is even doubtful that it could be, which would explain why Hume has simply chosen to remove any mention of it when he recompiled his theses on causation in the Enquiry concerning Human Understanding. Given this situation, an interesting question that naturally arises is to investigate the relations of logical or conceptual implication between these two principles. Hume seems to have thought that an answer to (2) would also be sufficient to provide an answer to (1). Henry Allison, in his turn, argued (in Custom and Reason in Hume, p. 94-97) that the two questions are logically independent. My proposal here is to try to show that there is indeed a logical dependency between them, but the implication is, rather, from (1) to (2). If accepted, this result may be particularly interesting for an interpretation of the scope of the so-called "Kant's reply to Hume" in the Second Analogy of Experience, which is structured as a proof of the a priori character of (1), but whose implications for (2) remain controversial.
Resumo:
Farmers have difficult of determining the evenness of transverse distribution and the working width, due the tests with this aim require equipments and complex methodologies. So, this study evaluates some alternative containers with the aim to allow a more accessible adjustment of the full width of the solid fertilizer spreaders. Four different containers were tested: i) standard container constructed in accordance with ISO 5690/1; ii) container of polyethylene (plastic trays) with screen shading to prevent the ricochet of material; iii) containers composed by boxes of long-life milk, and iv) containers composed by flowerpots (number 3.5). Also, three different spreaders were used for the tests. Alternative containers showed greater retention of particles than the standardized containers. The full width of work obtained for the coefficients of variation of 12.5; 15; 17.5 and 20%, ranged due the containers in the different pathways. The flowerpots of polyethylene showed similar results to the standardized containers. The heights of the containers were more important for its efficiency than its area of collection.
Resumo:
The principle of patient autonomy is a cornerstone of bioethics. According to this concept, patients should be given the power to make decisions related to their treatment. It is an important component of modern medical ethics, which has received much interest in current literature. However, the rate of participation of patients and their willingness to participate are variable according to the cultural, social and family environments in which they are inserted. The aim of this paper is to promote a brief descriptive review on autonomy, the preferences of patients and the use of informed consent as an instrument for the exercise of autonomy in literature, and to stress the lack of debate, as well as the pressing need for discussion of these current issues nationwide.
Resumo:
Cyanide-resistant alternative oxidase (AOX) is not limited to plant mitochondria and is widespread among several types of protists. The uncoupling protein (UCP) is much more widespread than previously believed, not only in tissues of higher animals but also in plants and in an amoeboid protozoan. The redox energy-dissipating pathway (AOX) and the proton electrochemical gradient energy-dissipating pathway (UCP) lead to the same final effect, i.e., a decrease in ATP synthesis and an increase in heat production. Studies with green tomato fruit mitochondria show that both proteins are present simultaneously in the membrane. This raises the question of a specific physiological role for each energy-dissipating system and of a possible functional connection between them (shared regulation). Linoleic acid, an abundant free fatty acid in plants which activates UCP, strongly inhibits cyanide-resistant respiration mediated by AOX. Moreover, studies of the evolution of AOX and UCP protein expression and of their activities during post-harvest ripening of tomato fruit show that AOX and plant UCP work sequentially: AOX activity decreases in early post-growing stages and UCP activity is decreased in late ripening stages. Electron partitioning between the alternative oxidase and the cytochrome pathway as well as H+ gradient partitioning between ATP synthase and UCP can be evaluated by the ADP/O method. This method facilitates description of the kinetics of energy-dissipating pathways and of ATP synthase when state 3 respiration is decreased by limitation of oxidizable substrate.
Resumo:
Modeling of water movement in non-saturated soil usually requires a large number of parameters and variables, such as initial soil water content, saturated water content and saturated hydraulic conductivity, which can be assessed relatively easily. Dimensional flow of water in the soil is usually modeled by a nonlinear partial differential equation, known as the Richards equation. Since this equation cannot be solved analytically in certain cases, one way to approach its solution is by numerical algorithms. The success of numerical models in describing the dynamics of water in the soil is closely related to the accuracy with which the water-physical parameters are determined. That has been a big challenge in the use of numerical models because these parameters are generally difficult to determine since they present great spatial variability in the soil. Therefore, it is necessary to develop and use methods that properly incorporate the uncertainties inherent to water displacement in soils. In this paper, a model based on fuzzy logic is used as an alternative to describe water flow in the vadose zone. This fuzzy model was developed to simulate the displacement of water in a non-vegetated crop soil during the period called the emergency phase. The principle of this model consists of a Mamdani fuzzy rule-based system in which the rules are based on the moisture content of adjacent soil layers. The performances of the results modeled by the fuzzy system were evaluated by the evolution of moisture profiles over time as compared to those obtained in the field. The results obtained through use of the fuzzy model provided satisfactory reproduction of soil moisture profiles.
Resumo:
The formulation of the so-called law of rectilinear diameter for the determination of the critical volume of substances in the concluding decades of the nineteenth century became in a very useful and acceptably exact alternative tool for researchers in the field of critical phenomena. Its corresponding original expression, and even those of its early few modifications, were so mathematically simple that their use did not limit to exclusively contribute to remove the by then experimental obstacle for the estimating of this critical parameter, but also extended along several decades in the increasing applications of the principle of corresponding states.
Resumo:
The resistance of barnyardgrass (Echinochloa crus-galli) to imidazolinone herbicides is a worldwide problem in paddy fields. A rapid diagnosis is required for the selection of adequate prevention and control practices. The objectives of this study were to develop expedite bioassays to identify the resistance to imidazolinone herbicides in barnyardgrass and to evaluate the efficacy of alternative herbicides for the post-emergence control of resistant biotypes. Three experiments were conducted to develop methods for diagnosis of resistance to imazethapyr and imazapyr + imazapic in barnyardgrass at the seed, seedling and tiller stages, and to carry out a pot experiment to determine the efficacy of six herbicides applied at post-emergence in 13 biotypes of barnyardgrass resistant to imidazolinones. The seed soaking bioassay was not able to differentiate the resistant and susceptible biotypes. The resistance of barnyardgrass to imidazolinones was effectively discriminated in the seedlings and tiller bioassays seven days after incubation at the concentrations of 0.001 and 0.0001 mM, respectively, for both imazethapyr and imazapyr + imazapic. The biotypes identified as resistant to imidazolinones showed different patterns of susceptibility to penoxsulam, bispyribac-sodium and pyrazosulfuron-ethyl, and were all controlled with profoxydim and cyhalofop-butyl. The seedling and tiller bioassays are effective in the diagnosis of barnyardgrass resistance to imidazolinone herbicides, providing an on-season opportunity to identify the need to use alternative herbicides to be applied at post-emergence for the control of the resistant biotypes.
Resumo:
ABSTRACTDepending on the cultivar, the use of desiccants in the preharvest can favor maintenance of physiological quality. The objective of the study was to assess the physiological quality of soybean seeds as due to the use of apreharvest desiccant and desiccation time in two harvests (2011/12 and 2012/13). The treatments were five soybean cultivars, two growth stages of application, a control (without desiccant application), and three desiccants (glufosinate-ammonium, carfentrazone-ethyl and paraquat) (2011/12 harvest). In the 2012/13 harvest the carfentrazone-ethyl desiccant was replaced by diquat. The physiological quality of seeds was assessed by the percentage of viability and vigor (cold test, tetrazolium test and accelerated aging test). In 2011/12 harvest, there was an early harvest in six days with the use of glufosinate-ammonium and paraquat desiccants, when desiccation was done in stage R7.1, with maintenance of seed quality; however it was dependent on the cultivar. In the 2012/13 harvest there was no early harvesting due to the presence of rain in the preharvest and the use of desiccation did not affect the physiological quality of the seeds either. Cultivar NA5909 RG was more tolerant to remaining in the cultivation environment and maintained higher viability than 90% and greater vigor of 71% by the cold test compared to cultivar BMX Turbo (2011/12 harvest). It is concluded that desiccation can be a viable alternative to the soybean early harvesting, but it depends on the cultivar, the time of desiccation, the active principle of the desiccant and the absence of rain in preharvest.
Resumo:
The use of unconventional sources of K for plants has been widely studied, but the effects of alternative materials on physiological seed quality are still relatively unknown. The objective of this study was to evaluate the physiological quality of soybean and wheat seeds after using different potassium sources in a crop succession. The experimental design was a completely randomized block with four replications. Treatments consisted of three K sources (KCl, alkaline rock and ground phonolite, with 58%, 11% and 8.42% of K2O, respectively) applied in four doses (0, 25, 50 and 100 kg K2O ha-1). Potassium doses were applied in soybean and their residual effects were evaluated on the following wheat crop. Soybean and wheat seeds were evaluated immediately after harvesting by tests for moisture content, seed weight, germination, first count, electrical conductivity, seedling length and seedling dry matter. Soybean plants fertilized with alternative sources of K produced heavier seeds with a lower coat permeability compared to KCl; the physiological quality of soybean seeds and the weight of wheat seeds increase due to higher K2O doses, independently of their source.
Resumo:
OBJECTIVE: To compare the immunogenicity of three yellow fever vaccines from WHO-17D and Brazilian 17DD substrains (different seed-lots). METHODS: An equivalence trial was carried out involving 1,087 adults in Rio de Janeiro. Vaccines produced by Bio-Manguinhos, Fiocruz (Rio de Janeiro, Brazil) were administered following standardized procedures adapted to allow blocked randomized allocation of participants to coded vaccine types (double-blind). Neutralizing yellow fever antibody titters were compared in pre- and post-immunization serum samples. Equivalence was defined as a difference of no more than five percentage points in seroconversion rates, and ratio between Geometric Mean Titters (GMT) higher than 0.67. RESULTS: Seroconversion rates were 98% or higher among subjects previously seronegative, and 90% or more of the total cohort of vaccinees, including those previously seropositive. Differences in seroconversion ranged from -0.05% to -3.02%. The intensity of the immune response was also very similar across vaccines: 14.5 to 18.6 IU/mL. GMT ratios ranged from 0.78 to 0.93. Taking the placebo group into account, the vaccines explained 93% of seroconversion. Viremia was detected in 2.7% of vaccinated subjects from Day 3 to Day 7. CONCLUSIONS: The equivalent immunogenicity of yellow fever vaccines from the 17D and 17DD substrains was demonstrated for the first time in placebo-controlled double-blind randomized trial. The study completed the clinical validation process of a new vaccine seed-lot, provided evidence for use of alternative attenuated virus substrains in vaccine production for a major manufacturer, and for the utilization of the 17DD vaccine in other countries.
Resumo:
OBJECTIVE: To assess the determinants of the lack of pharmacological treatment for hypertension. METHODS: In 2005, 3,323 Mozambicans aged 25-64 years old were evaluated. Blood pressure, weight, height and smoking status were assessed following the Stepwise Approach to Chronic Disease Risk Factor Surveillance. Hypertensives (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg and/or antihypertensive drug therapy) were evaluated for awareness of their condition, pharmacological and non-pharmacological management, as well as use of herbal or traditional remedies. Prevalence ratios (PR) were calculated, adjusted for sociodemographic characteristics, cardiovascular risk factors and non-pharmacological treatment. RESULTS: Most of the hypertensive subjects (92.3%), and nearly half of those aware of their condition were not treated pharmacologically. Among the aware, the prevalence of untreated hypertension was higher in men {PR = 1.61; 95% confidence interval (95%CI 1.10;2.36)} and was lower in subjects under non-pharmacological treatment (PR = 0.58; 95%CI 0.42;0.79); there was no significant association with traditional treatments (PR = 0.75; 95%CI 0.44;1.26). CONCLUSIONS: The lack of pharmacological treatment for hypertension was more frequent in men, and was not influenced by the presence of other cardiovascular risk factors; it could not be explained by the use of alternative treatments as herbal/traditional medicines or non-pharmacological management. It is important to understand the reasons behind the lack of management of diagnosed hypertension and to implement appropriate corrective actions to reduce the gap in the access to healthcare between developed and developing countries.
Resumo:
Sera from 299 fishermen 16 to 80 years old, residents in Cananeia and Iguape counties, southern cost of São Paulo State, Brazil, were studied in order to identify a possible association between the prevalence of specific antibodies to the hepatitis B virus (HBV) and exposure to haematophagus mosquitoes evaluated by the prevalence of arbovirus antibodies. This professional group presented the highest prevalence of arbovirus antibodies (54.1%) in past investigations carried out in this heavily forested region. Detection of antibody to hepatitis B core antigen (anti-HBc) in the sera was done by enzyme immunoassay (Roche). Prevalence of anti-HBc antibodies in this group was 31.4% (94/299) which is very high compared with 7.2% to 15.0% for different groups of healthy adults in State of São Paulo. No significant difference is observed between the prevalences of HBV antibodies in Iguape and Cananeia. Prevalence of anti-HBc and anti-arbovirus antibodies increases with age. There is a concordance in the distribution according to age groups of the frequency of anti-HBc and anti-arbovirus positive sera. Ag HBs was detected in 4% of the studied sera. These results support the hypothesis that the transmission of the hepatitis B virus and the arboviruses may be due to the same factor, one of the possibilities would be by anthropophilic mosquitoes.
Resumo:
A laboratory study was conducted to test the toxicity of synthetic insecticides added to defibrinated sheep blood kept at room temperature and offered as food to the following triatomine species: Triatoma infestans, Panstrongylus megistus, Triatoma vitticeps, Triatoma pseudomaculata, Triatoma brasiliensis and Rhodnius prolixus. The insecticides used, at a concentration of 1g/l, were: HCH, DDT, Malathion and Trichlorfon, and the lethalithy observed at the end of a 7-day period varied according to the active principle of each. HCH was the most effective by the oral route, killing 100% of the insects, except P. megistus (95.7%) and T. pseudomaculata (94.1%). Trichlorfon killed the insects at rates ranging from 71.8% (T. vitticeps) to 98% (R. prolixus). Malathion was slightly less efficient, killing the insects at rates from 56.8% (T. vitticeps) to 97% (T.brasiliensis). DDT was the least effective, with a killing rate of 10% (T. vitticeps) to 75% (T.brasiliensis). Since the tests were performed at room temperature, we suggest that baits of this type should be tried for the control of triatomines in the field.