967 resultados para Experimental conditions


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The sensory characteristics color and flavor of food play an important role not only in the selection, but also in the determination of consumption, satiation, and ingestion. With the objective to determine and evaluate the influence of color on the acceptance and identification of flavor of foods for adults, sensory analysis was performed on jellies by non-trained tasters of both sexes aged between 18 and 60 years (1750 tests). A hedonic scale and combinations of five colors (red, yellow, green, blue and purple) and three flavors (strawberry, pineapple, and limes) were used in the acceptance test totaling 15 samples. In the duo-trio discrimination test, together with the reference sample (R), one sample identical to the reference and another of identical color and different flavor were offered, and the judges were requested to identify the sample that was different from the reference sample. The colors used did not influence the acceptance of the samples (P > 0.05), and as there was not significant interaction between color and flavor. However, the limes flavor negatively influenced acceptance when compared to the other flavors. With regard to flavor differentiation, the colors used did not influence flavor identification (P > 0.05); However, differentiated behavior was identified between females and males, and the latter were more error-prone. Therefore, under the experimental conditions tested, color did not influence the acceptance and identification of the flavor of the samples by adults.

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This study aims to optimize an alternative method of extraction of carrageenan without previous alkaline treatment and ethanol precipitation using Response Surface Methodology (RSM). In order to introduce an innovation in the isolation step, atomization drying was used reducing the time for obtaining dry carrageenan powder. The effects of extraction time and temperature on yield, gel strength, and viscosity were evaluated. Furthermore, the extracted material was submitted to structural analysis, by infrared spectroscopy and nuclear magnetic resonance spectroscopy (¹H-NMR), and chemical composition analysis. Results showed that the generated regression models adequately explained the data variation. Carrageenan yield and gel viscosity were influenced only by the extraction temperature. However, gel strength was influenced by both, extraction time and extraction temperature. Optimal extraction conditions were 74 ºC and 4 hours. In these conditions, the carrageenan extract properties determined by the polynomial model were 31.17%, 158.27 g.cm-2, and 29.5 cP for yield, gel strength, and viscosity, respectively, while under the experimental conditions they were 35.8 ± 4.68%, 112.50 ± 4.96 g.cm-2, and 16.01 ± 1.03 cP, respectively. The chemical composition, nuclear magnetic resonance spectroscopy, and infrared spectroscopy analyses showed that the crude carrageenan extracted is composed mainly of κ-carrageenan.

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The opportunity to supplement common cassava biscuits with a product of higher nutritional value meets consumer expectations. In this work it was studied the effects of process parameters and flaxseed addition on physical properties of expanded snacks. Extrusion process was carried out using a single screw extruder in a factorial central composite rotatable design with four factors: flaxseed flour percentage (0-20%), moisture (12-20%), extrusion temperature (90-130 °C) and screw speed (190-270). The effect of extrusion variables was investigated in terms of expansion index, specific volume, water absorption index, water solubility index, color parameters (L*, a* ,b*) and hardness. The data analysis showed that variable parameters of the extrusion process and flaxseed flour affected physical properties of puffed snacks. Among the experimental conditions used in the present study, expanded snack products with good physical properties can be obtained under the conditions of 10% flaxseed flour, 230 rpm screw speed, temperature of 90 °C and moisture of 12%.

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The physical and chemical alterations in palm oil during continuous industrial par frying of breaded chicken snacks were evaluated using a pseudo first-order kinetic model. The acidity index, refractive index, concentration of polar compounds, viscosity, color, and absorbance (232 and 268 nm) of 238 samples of the frying oil collected during 26 days of production were analyzed. For all of the analyses, the results of the oil were below the limits recommended for oil disposal, indicating that the processing conditions were safe and that under these experimental conditions the oil remained suitable for frying. The linear regressions were significant for refractive index, content of polar compounds, and lightness (L*). The content of polar compounds was determined using a cooking oil tester, and it had the best fit to the proposed model and can be used as an effective index for monitoring palm oil during the continuous par frying of breaded chicken snacks. The high turnover rate of the oil was important for maintaining the oil in good running conditions.

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Potato pulp waste (PPW) drying was investigated under different experimental conditions (temperatures from 50 to 70 °C and air flow from 0.06 to 0.092 m³ m- 2 s- 1) as a possible way to recover the waste generated by potato chip industries and to select the best-fit model to the experimental results of PPW drying. As a criterion to evaluate the fitting of mathematical models, a method based on the sum of the scores assigned to the four evaluated statistical parameters was used: regression coefficient (R²), relative mean error P (%), root mean square error (RMSE), and reduced chi-square (χ²). The results revealed that temperature and air velocity are important parameters to reduce PPW drying time. The models Midilli and Diffusion had the lowest sum values, i.e., with the best fit to the drying data, satisfactorily representing the drying kinetics of PPW.

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Suuri osa käytössä olevista lääkeaineista on kiraalisia yhdisteitä. Lääkevalmisteet sisältävät yhdisteen enantiomeerien ominaisuuksista riippuen joko yksittäistä enantiomeeria tai näiden seosta. Antitromboottisiin eli veren hyytymistä estäviin lääkeaineisiin kuuluvat varfariini ja rivaroksabaani ovat kiraalisia yhdisteitä, joiden enantiomeerien ominaisuudet poikkeavat antitromboottisen vaikutuksen voimakkuuden suhteen. Varfariinia käytetään kliinisesti enantiomeeriensa raseemisena seoksena, kun taas rivaroksabaani on käytössä lääkevalmisteena puhtaana S-enantiomeerinaan. Lääkeaineen enantiomeerien erottaminen toisistaan on tärkeää esimerkiksi enantiomeerien puhdistamiseksi, lääkevalmisteen oikean koostumuksen varmistamiseksi tai yksittäisten enantiomeerien käyttäytymisen arvioimiseksi elimistössä. Tässä kirjallisuustyössä käsiteltiin nestekromatografian käyttöä antitromboottisiin lääkeaineisiin kuuluvien antikoagulanttien enantiomeerien fraktioinnissa. Kirjallisuudesta saadun tiedon perusteella arvioitiin, millä erotusmateriaaleilla ja millaisissa koeolosuhteissa varfariinin sekä rivaroksabaanin enantiomeerit tulisi erottaa toisistaan. Varfariinin enantiomeerien erotukseen parhaiten sopivaksi erotusmateriaaliksi todettiin kirjallisuuden perusteella kiraalinen vankomysiinipohjainen stationaarifaasi (Chirobiotic V) metanolin, etikkahapon ja veden seoksen toimiessa eluenttina. Eluentin virtausnopeudella 0,3 mL/min ja pienellä injektiotilavuudella varfariinin enantiomeerit saatiin erottumaan täydellisesti ja nopeasti toisistaan. Kirjallisuuden perusteella rivaroksabaanin enantiomeerien erotuksessa erotusmateriaalina toimii parhaiten kiraalinen selluloosapohjainen stationaarifaasi (Chiralcel OD-RH), kun eluenttina käytetään n-heksaanin ja isopropanolin seosta virtausnopeudella 1 mL/min. Varfariinin ja rivaroksabaanin enantiomeerien fraktiointiin parhaiten sopivia menetelmiä voidaan käyttää eri tilanteissa, kuten lääkevalmisteiden laadunvarmistuksessa tai enantiomeerien erotuksessa niiden synteesin jälkeen.

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The frequency and type of agonistic displays involved in male-male encounters should be significantly influenced by the presence of females. Discrete agonistic displays vary in energy expenditure and risk, and therefore should be dependent on available resources. The influence of live females and the scent of females, on the frequency of male agonistic displays was observed in a laboratory terrarium using the field cricket Gryllus bimaculatus. The effect of energy constraints on display frequency was also determined. Half the males were fed a diet high in protein and fet; the other males were fed a lower quality diet, for a 7-11 day period. The frequency of five individual displays and mating frequency were recorded using an Event Recorder and notebook. Each group of males was presented with three experimental conditions, over three days, involving the presence or absence of live females and female scent. The presence of females elicited an increase in all displays except antennation; female scent increased the frequency of antennations, mandible flares and grapples, but to a lesser extent than did live females. The frequency of grapples significantly increased for males fed the high quality diet; however diet did not influence the other displays. The combined influence of diet and condition was significant for mandible flare only. Mating frequency was not influenced by diet. However, the frequency ofthe displays were positively correlated with mating frequency for high quality fed males. Escalated displays involving high costs, such as grapple and mandible flare, increased in frequency when the benefits of winning contests were high in G.bimaculatus. Escalation to grapple behaviour was less evident for males fed the lower quality diet as this imposed energy constraints on high cost displays.

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This experimental study examined the effects of cooperative learning and a question-answering strategy called elaborative interrogation ("Why is this fact true?") on the learning of factual information about familiar animals. Retention gains were compared across four study conditions: elaborative-interrogation-plus-cooperative learning, cooperative-learning, elaborative-interrogation, and reading-control. Sixth-grade students (n=68) were randomly assigned to the four conditions. All participants were given initial training and practice in cooperative learning procedures via three 45-minute sessions. After studying 36 facts about six animals, students' retention gains were measured via immediate free recall, immediate matched association, 30-day, and GO-day matched association tests. A priori comparisons were made to analyze the data. For immediate free recall and immediate matched association, significant differences were found between students in the three experimental conditions versus those in the control condition. Elaborative-interrogation and elaborativeinterrogation- plus-cooperative-learning also promoted longterm retention (measured via 30-day matched association) of the material relative to repetitive reading with elaborative-interrogation promoting the most durable gains (measured via GO-day matched association). The relationship between the types of elaborative responses and probability of subsequent retention was also examined. Even when students were unable to provide adequate answers to the why questions, learning was facilitated more so than repetitive reading. In general, generation of adequate elaborations was associated with greater probability of recall than was provision of inadequate answers. The findings of the study demonstrate that cooperative learning and the use of elaborative interrogation, both individually and collaboratively, are effective classroom procedures for facilitating children's learning of new information.

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This thesis can be broken down into two sections. Section one is a study . of the ionization mechanisms and the ion source optimization for Fast Atom Bombardment (FAB) ionization. For this study, several specially designed probe tips were created and tested under various experimental conditions. The aIm of this section is to understand the operating characteristics of a FAB IOn source better. The second section involves the study of several Vitamin B6 Schiff Base complexes using both positive and negative ion FAB MS. This section is an exploration of the usefulness of FAB MS as a structure probe for the metalcoordination complexes of Vitamin B6.

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This study investigated three methods for teaching children how to spell. Third grade students were divided into three conditions for a one-week training period consisting of 15- to 20-minute lessons. One of the two experimental conditions used a whole language approach along with explicit strategy instruction. The second condition used strategy instruction within a traditional setting. The control used strictly a whole language approach to le~ing hO\\l to spell. The spelling perfonnance of all three conditions improved after the one-week training period. However, students in the strategy instruction groups did significantly better on the study "'7ords than the whole language only group. The students in whole-Ianguage-plusstrateg)! instruction outperformed both other groups. Significantly better spelling perfonnance was observed even at the nine-week posttest. This study frrst supported the hypothesis that children can make significantly greater improven1ents in their spelling when explicitly taught how to use spelling strategies. Secondl)', this study indicated that whole language provided a relevant context for the study words, clearly giving the students in the whole-Ianguage-plus-strategy condition an additional advantage.

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Ox amyl , an insecticide/nematicide with the chemical name; methyl ~'. ~·-dimethyl-~-(methylcarbamoyl)oxy-l-thiooxamimidate, and its major degradation compound; oxime or oximino compound, methyl ~',~'-dimethyl-~-hydroxy-l-thiooxamimidate were studied in this work. NMR and mass spectrometry were utilized in the structural studies. An attempt was made to explain the fragmentation patterns of some major peaks in the mass spectra of oxamyl and oxime. A new gas chromatographic method for the detection and determination of submicrogram levels of intact oxamyl using a electron-capture detector was developed. The principle of this method is to produce a derivative which is highly sensitive to an electron-capture detector. The derivative described is dinitrophenyl methylamine( DNPMA ) • Experimental conditions such as pH , reaction temperature , reaction time, the amount of reagent ( Dinitrofluaro benzene) etc. were thoroughly investigated and optimized. This method was successfully applied to the determination of oxamyl residues in tobacco leaves and soil. Throughout this J9D:oject , thin layer chromatography was also used in the separation:and clean up of oxamyl and oxime samples.

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Forty students from regular, grade five classes were divided into two groups of twenty, a good reader group and a' poor reader group, on the basis. of their reading scores on Canadian Achievement Tests. .The subjects took. part in four experimental conditions iM which they .learned lists of pronounceable and unprono~nceable pseudowords, some with semantic referents, and responded to questions designed tci test visual perceptu~l learning and lexical ·and semantic association learning. It' was hypothesized "that the good reade~ group would be able to make use of graphemic and phonemic redundancy patterns in order to improv~·visuSl perceptual learning and lexical and semantic association lea~ningto a greater extent. than would .the poor reader gr6up. The data supported this hypothesis, and also indicated that, although the poor readers were less adept at using familiar sound and letter patterns, they were more dependent on· such pa~terns as an aid to visual recognition memory and semantic recall than were the good readers. It wa.s postulated that poor readers are in a double- ~ . bind situatio~ of having to choose between using weak graphemic-semantic associations or gr~pheme-phoneme associations which are also weak and which have hindered them in developing automaticity in. reading.

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Underlying intergroup perceptions include processes of social projection (perceiving personal traitslbeliefs in others, see Krueger 1998) and meta-stereotyping (thinking about other groups' perceptions of one's own group, see Vorauer et aI., 1998). Two studies were conducted to investigate social projection and meta-stereotypes in the domain of White-Black racial relations. Study 1, a correlational study, examined the social projection of prejudice and 'prejudiced' meta-stereotypes among Whites. Results revealed that (a) Whites socially projected their intergroup attitudes onto other Whites (and Blacks) [i.e., Whites higher in prejudice against Blacks believed a large percentage of Whites (Blacks) are prejudiced against Blacks (Whites), whereas Whites low in prejudice believed a smaller percentage of Whites (Blacks) are prejudiced]; (b) Whites held the meta:..stereotype that their group (Whites) is viewed by Blacks to be prejudiced; and (c) prejudiced meta-stereotypes may be formed through the social projection of intergroup attitudes (result of path-model tests). Further, several correlates of social projection and meta-stereotypes were identified, including the finding that feeling negatively stereotyped by an outgroup predicted outgroup avoidance through heightened intergroup anxiety. Study 2 replicated and extended these findings, investigating the social projection of ingroup favouritism and meta- and other-stereotypes about ingroup favouritism. These processes were examined experimentally using an anticipated intergroup contact paradigm. The goal was to understand the experimental conditions under which people would display the strongest social projection of intergroup attitudes, and when experimentally induced meta-stereotypes (vs. other-stereotypes; beliefs about the group 11 preferences of one's outgroup) would be most damaging to intergroup contact. White participants were randomly assigned to one of six conditions and received (alleged) feedback from a previously completed computer-based test. Depending on condition, this information suggested that: (a) the participant favoured Whites over Blacks; (b) previous White participants favoured Whites over Blacks; (c) the participant's Black partner favoured Blacks over Whites; (d) previous Black participants favoured Blacks over Whites; (e) the participant's Black partner viewed the participant to favour Whites over Blacks; or (£) Black participants previously participating viewed Whites to favour Whites over Blacks. In a defensive reaction, Whites exhibited enhanced social projection of personal intergroup attitudes onto their ingroup under experimental manipulations characterized by self-concept threat (i.e., when the computer revealed that the participant favoured the ingroup or was viewed to favour the ingroup). Manipulated meta- and otherstereotype information that introduced intergroup contact threat, on the other hand, each exerted a strong negative impact on intergroup contact expectations (e.g., anxiety). Personal meta-stereotype manipulations (i.e., when the participant was informed that her/ his partner thinks s/he favours the ingroup) exerted an especially negative impact on intergroup behaviour, evidenced by increased avoidance of the upcoming interracial interaction. In contrast, personal self-stereotype manipulations (i.e., computer revealed that one favoured the ingroup) ironically improved upcoming intergroup contact expectations and intentions, likely due to an attempt to reduce the discomfort of holding negative intergroup attitudes. Implications and directions for future research are considered.

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The relationship between testosterone concentrations and aggressive behaviour in studies of people has produced very inconsistent findings. However, one consistent fmding that has emerged is that competitive and aggressive interactions potentiate testosterone release in both human and non-human species. It has been argued that socially-induced alterations in testosterone concentrations may function to influence ongoing and/or future social behaviour. Nonetheless, few studies have empirically tested this hypothesis. The current series of experiments was designed to address the extent to which competitioninduced fluctuations in testosterone concentrations were associated with ongoing and/or subsequent social behaviour. In Study 1, men (n = 38) provided saliva samples prior to, and at the conclusion of, the Point Subtraction Aggression Paradigm (PSAP). Although baseline testosterone concentrations were not related to aggressive behaviour, there was a positive correlation between change in testosterone and aggressive behaviour such that men who were most aggressive on the PSAP demonstrated the largest increase in testosterone concentrations. Furthermore, a rise in testosterone during the PSAP predicted willingness to choose a subsequent competitive task. In Study 2, men and women provided saliva samples prior to and after competing against a same-sex opponent on the Number Tracing Task (NTT). The outcome of the competition was rigged such that half of the individuals won most of the races, while the other half lost most of the races, thus experimentally creating a winner and loser in the laboratory. Following the competitive interaction, men and women played the PSAP with their same-sex partner. Results indicated that men selected the aggressive response (but not reward or protection responses), more frequently than women. For men assigned to the loss condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour. For men assigned to the win condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour, but only among those men who scored high on trait dominance. Change in testosterone and trait dominance did not predict aggressive behaviour in women. In Study 3, men provided saliva samples prior to, during, and at the end of the PSAP. They were randomly assigned to one of four experimental conditions that differed in the extent to which they were provoked and whether they received reward for behaving aggressively (i.e., stealing points). Results indicated that baseline testosterone concentrations did not correlate with aggression in any of the experimental conditions. Consistent with Study 1, there was a positive correlation between change in testosterone and aggressive behaviour among men who were provoked, but did not receive reward for aggression (i.e., reactive condition). Men who were provoked but did not receive reward for aggression enjoyed the task the most and were more likely to choose the competitive versus non-competitive task relative to men assigned to the other experimental conditions. Also, individual differences in aggressive behaviour among these men were positively correlated with the extent to which they enjoyed the task. Together, these studies indicate that testosterone dynamics within the context of competition influence subsequent competitive and aggressive behaviours in humans and that testosterone may be a marker of the intrinsically rewarding nature of costly aggressive behaviour.

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Converging evidence has demonstrated learning advantages when an individual is instructed to focus their attention externally. However, many of the motor tasks utilized in past research had clear external objectives (i.e., putting accuracy), creating a compatible relationship between an external focus of attention (i.e., outcome) and an external task objective (i.e., putting accuracy). The present study examined whether or not the consistency of instructions and task objective would differentially impact the acquisition of a golf putting task. Participants performed a putting task in a control condition or in one of four experimental conditions resulting from the factorial interaction of task instructions (internal or external) and task objective (internal or external). The retention and transfer data revealed that participants who received an external task objective demonstrated superior outcome scores. Participants who received technique information paired with outcome information demonstrated superior technique scores.