Photocatalytic Detoxification of Antibiotic- and Bacteria-Contaminated Water using Cobalt-Doped Ni–Zn Ferrites Magnetic Separable Nanopowders

Here, metronidazole (MZ) antibiotic degradation and bactericidal efficacy of Co–Ni0.5Zn0.5Fe2O4 (Co–NZF) with and without photoactivation by UV light is reported as a viable cost-competitive water disinfection solution. Co–NZF has a total pore volume of 0.298 cm3 g− 1, a specific surface area of 70.2 m2 g− 1 and sufficiently high magnetic properties (80.35 emu g− 1). After 360 min of UV–assisted irradiation at pH 3, 10 mg Co–NZF, and 4 mM H2O2, the maximum MZ degradation was reached (92.8%). The adsorption result of 10 mg Co–NZF in the dark for 12 h resulted in 70.2% MZ removal, whereas MZ self-degradation was significantly minimal in a blank trial. In the presence of interfering anions and very high molecular weight tylosin antibiotic, Co–NZF maintained 51.7–75.4% degradation efficiency. The effect of the Co–NZF dosage on the viability of Staphylococcus aureus and Escherichia coli strains showed that 15 mg of the catalyst was sufficient to cause bactericidal activity after 180 min in the presence of UV light, while 25 mg is needed under dark conditions. In addition, when compared to Escherichia coli strains, Co–NZF showed higher inhibition against Staphylococcus aureus in time-kill experiments under dose variation.

Optimal plot size in the evaluation of papaya scions: proposal and comparison of methods

ABSTRACT Evaluating the quality of scions is extremely important and it can be done by characteristics of shoots and roots. This experiment evaluated height of the aerial part, stem diameter, number of leaves, petiole length and length of roots of papaya seedlings. Analyses were performed from a blank trial with 240 seedlings of "Golden Pecíolo Curto". The determination of the optimum plot size was done by applying the methods of maximum curvature, maximum curvature of coefficient of variation and a new proposed method, which incorporates the bootstrap resampling simulation to the maximum curvature method. According to the results obtained, five is the optimal number of seedlings of papaya "Golden Pecíolo Curto" per plot. The proposed method of bootstrap simulation with replacement provides optimal plot sizes equal or higher than the maximum curvature method and provides same plot size than maximum curvature method of the coefficient of variation.

The ability of language-disordered children to use and modify hypotheses in discrimination learning

Blank-trial probe discrimination learning tasks were used to evaluate the hypothesis-testing abilities of 15 language-disordered and 30 normally developing children matched for mental age and language age. Children were presented with a series of two-dimensional learning set and orthogonal problems. No significant group differences were found in the learning set problems. All the children reached learning set criterion quickly, used a high proportion of simple object hypotheses, and maintained a high proportion of confirmed hypotheses. On the orthogonal problems, however, the language-disordered and mental-aged- (MA) matched children performed significantly better than the younger normal children. These findings suggest that the cognitive and linguistic deficits language-disordered children exhibit do not reflect an underlying failure to generate and test hypotheses. This conclusion, however, does not seem to apply to all language-disordered children. In the final section of the paper, language-disordered children's cognitive strengths and weaknesses are interpreted within the context of an information-processing model.

Effects of Concrete Reward/Cost Contingencies upon Discrimination-Learning Styles of Prekindergarten and Kindergarten Children

13 kindergarten and 10 prekindergarten children received elaborated instructions and material reward/cost contingencies in discrimination-learning problems containing blank-trial probes. Kindergarteners' performance was superior both to that obtained in a previous study, and to prekindergarteners' performance. Further exploration of task variables and individual differences is suggested.

The Inference of Covert Hypotheses by Verbal Reports in Concept-Learning Research

A paradigm designed to examine the degree to which verbal reports represent the subject's learning was evaluated using a concept-acquisition task. Specifically, the degree to which hypotheses verbalized during the concept-acquisition procedure represent the covert hypotheses controlling category responding was examined. Subjects were required to make category responses, verbal reports, and sorts and re-sorts (blank-trial probes) of the stimuli at intervals in a reception paradigm. By comparing the sorts made during the acquisition procedure, the re-sorts after a 1-week delay, and the sorts made by subjects who had not participated in the acquisition procedure, it was determined that the verbal reports do not accurately represent the underlying hypothesis-testing process under all conditions. Verbal reports elicited at the beginning of the acquisition procedure and at criterion accurately represented the underlying hypotheses; those elicited at intervening points did not. The ambiguity of the verbal reports was a similar function of acquisition trials.

Cognitive Strategies as a Dependent Variable in Media Research

Although the need to investigate the cognitive processes by media research was recognized as early as 1961, there has been hardly any such attempt. The lack of experimental techniques by which the “black box” can be reached is probably responsible for the lack of research attention. This experiment employs a technique called blank trial to investigate cognitive strategies used by S in solving problems presented by slide. It is assumed that this technique may systematically investigate and presumably externalize cognitive processes.