The combined effects of pH and temperature on red pigment production and fungal morphology were evaluated in a submerged culture
of Penicillium purpurogenum GH2, using Czapek-Dox media with d-xylose as a carbon source. An experimental design with a factorial fix was used: three pH values (5, 7, and 9) and two temperature
levels (24 and 34 °C) were evaluated. The highest production of red pigment (2.46 g/L) was reached with a pH value of 5 and
a temperature of 24 °C. Biomass and red pigment production were not directly associated. This study demonstrates that P. purpurogenum GH2 produces a pigment of potential interest to the food industry. It also shows the feasibility of producing and obtaining
natural water-soluble pigments for potential use in food industries. A strong combined effect (p<0.05) of pH and temperature was associated with maximal red pigment production (2.46 g/L). 相似文献
AbstractThis paper is intended as an exploration of university faculty and students’ perceptions of a number of dimensions involved in the written composition of academic texts. We analysed the responses to scale 3 in the European Writing Survey (EUWRIT) (in its Spanish version: Encuesta Europea sobre la Escritura Académica, EEEA) by a group of social science and humanities students (n = 1,030) and faculty (n = 230) from nine Spanish universities. We then examined the similarities and differences in their perceptions and established a factorial structure of the different dimensions underlying the writing process. The data indicate that both groups concur in the value assigned to both changing ideas in the course of the composition process (although this process seems to be understood differently by each group) and the revision and feedback processes. The students, however, claim to be involved in more planning and previous reading activities than the teachers perceive them to be. The significance of these results for a process-oriented perspective in academic writing is discussed. 相似文献
When students are grouped into school tracks, this has lasting consequences for their learning and later careers. In Germany to date, some groups of students (boys, ethnic minority students) are underrepresented in the highest track. Stereotypes about these groups exist that entail negative expectations about their suitability for the highest track. Based on the shifting standards model, the present research examines if and how stereotypes influence tracking recommendations. According to this theory, members of negatively stereotyped groups will be judged more leniently or more strictly depending on the framing of the judgment situation (by inducing minimum or confirmatory standards). N = 280 teacher students participated in a vignette study in which they had to choose the amount of positive evidence for suitability they wanted to see before deciding to recommend a fictitious student to the highest track. A 2 (judgment standard: minimum vs. confirmatory) × 2 (target student’s gender: male vs. female) × 2 (target student’s ethnicity: no migration background vs. Turkish migration background) between-subjects design was used. No effects of target gender occurred, but the expected interaction of target’s ethnicity and judgment standard emerged. In the minimum standard condition, less evidence was required for the ethnic minority student to be recommended for the highest track compared to the majority student. In the confirmatory standards condition, however, participants tended to require less evidence for the ethnic majority student. Our experiment underlines the importance of the framing of the recommendation situation, resulting in a more lenient or stricter assessment of negatively stereotyped groups.
The main objective of this research was to review the characteristics of portfolios and their outcomes for teaching professionalism to undergraduate medical students. A systematic review on the use of portfolios in teaching professionalism to medical students identified 1257 papers. Of these, 11 articles met all inclusion criteria. According to the papers, the use of portfolios for teaching professionalism shows versatility, supports learning strategies and has the potential to be used in different contexts, including for formative and summative purposes. The weaknesses were based on the artificiality of the reflections, deficient instructions, time-consuming processes and preference among students for other teaching methods. Students complained about feeling that the reflection was ‘forced’, and they tended to write based on social conventions rather than reveal their true thoughts. Reflection is a powerful component of the portfolio, but the method by which it is taught could easily ruin its potential to boost professionalism. Requiring reflection did not ensure its achievement; increased understanding by students regarding how and why they were doing it, the clarity of assessment methods and constructive feedback might strengthen the potential for success. A framework was designed to support faculty members in developing and applying portfolios with a clear and broad view of this teaching strategy. 相似文献
Basic numerical representations are seen as the building block for the successful development of more complex numerical and arithmetic competencies. Extending previous studies focusing on improving basic numerical representations by means of embodied training schemes, the current study focused on an embodied training of children’s place-value understanding. In this vein, 49 secondgraders were trained on solving a number line estimation task by stepping on different fields of a dance mat allowing for separate estimations of tens and units with more effort needed to step on the tens. In a partially randomized cross-over design, two control conditions were used to controll for training effects caused exclusively by the numerical content trained or the use of the dance mat. Interestingly, results revealed specific training effects after both the embodied and the control conditions. However, training effects were significantly more pronounced after the embodied training, thereby providing further evidence for the benefit of an embodied training of the place-value structure of the Arabic number system. 相似文献
The present research examines discordant acculturation attitudes of host society members and immigrants as an antecedent to intergroup threat. Based on integrated threat theory and the concordance model of acculturation, we posited that discordance on culture maintenance and on desire for contact would predict intergroup threat beyond the influence of other antecedents of threat, such as in-group identification, knowledge, and negative contact. A study with 202 German host society members and 151 Turkish and Italian immigrants was conducted. In line with our assumptions, path analyses revealed that culture discordance and contact discordance contribute independently to the prediction of realistic threat, symbolic threat, and intergroup anxiety for host society members and immigrants. Moreover, differences in threat between cultures were mediated by the discordance in acculturation attitudes. 相似文献
