Decrease of preccurent behavior as training increases : effects of task complexity

When someone is described as memorizing ~ phone number, part of what is being asserted is that the person is capable of dialing the number without looking it up in the directory. Such responses, which may decrease and stop occurring as training increases, can be interpreted as nonrequired precurrent behavior. In different experiments, participants could look up an auxiliary screen to see the numbers (Experiment 1) or arbitrary characters (Experiment 3) corresponding to different shapes. In Experiment 2, a typing task with a covered keyboard was used, in which participants could look up an auxiliary screen to see key positions. Duration of precurrent response, divided by correct current responses, decreased as a linear function of the logarithm ot trials in ali three experiments. In Experiment 3, the complexity of the task was changed, by altering the number of responses to be learned per pair, per position, and in the total task. Results indicated that these variables produced systematic effects on performance and are compatible with an interpretation of task complexity based upon the quantification of the programmed contingencies of reinforcement

Examining the moderating effect of individual-level cultural values on users’ acceptance of E-learning in developing countries: a structural equation modeling of an extended technology acceptance model

In this study, we examine the effects of individual-level culture on the adoption and acceptance of e-learning tools by students in Lebanon using a theoretical framework based on the Technology Acceptance Model (TAM). To overcome possible limitations of using TAM in developing countries, we extend TAM to include subjective norms (SN) and quality of work life constructs as additional constructs and a number of cultural variables as moderators. The four cultural dimensions of masculinity/femininity (MF), individualism/collectivism, power distance and uncertainty avoidance were measured at the individual level to enable them to be integrated into the extended TAM as moderators and a research model was developed based on previous literature. To test the hypothesised model, data were collected from 569 undergraduate and postgraduate students using e-learning tools in Lebanon via questionnaire. The collected data were analysed using the structural equation modelling technique in conjunction with multi-group analysis. As hypothesised, the results of the study revealed perceived usefulness (PU), perceived ease of use (PEOU), SN and quality of work life to be significant determinants of students’ behavioural intention (BI) towards e-learning. The empirical results also demonstrated that the relationship between SN and BI was particularly sensitive to differences in individual-cultural values, with significant moderating effects observed for all four of the cultural dimensions studied. Some moderating effects of culture were also found for both PU and PEOU, however, contrary to expectations the effect of quality of work life was not found to be moderated by MF as some previous authors have predicted. The implications of these results to both theory and practice are explored in the paper

Psicología Y educación a distancia : una revisión de la literatura

O presente estudo investigou as contribuições da Psicologia para a educação a distância – EAD. Para isso, realizou-se revisão bibliográfica de publicações nacionais, entre 1999 e 2009, nas bases de dados SciELO, Lilacs, PsycINFO, BVS e Google Acadêmico. Foram selecionados 69 estudos, dos quais se excluíram 15, por não serem compatíveis com a pesquisa. Os resultados evidenciaram nove eixos temáticos: (1) tecnologia educacional a distância com fundamentos psicológicos, (2) afeição, (3) papel do tutor/professor, (4) teorias psicológicas, (5) interatividade, (6) evasão, (7) relatos de experiências, (8) avaliação de treinamento, desenvolvimento e educação a distância e (9) outros. Os temas tecnologia educacional a distância com fundamentos psicológicos e afeição obtiveram maior frequência nas publicações. Neste estudo, registrou-se, também, que, embora em ascensão desde 2006, os anos de maiores publicações da Psicologia na educação a distância foram 2008 e 2009. Sugere-se que estudos futuros ampliem esta pesquisa para incluir bases de dados internacionais.This study investigated the contributions of Psychology to Distance Learning. A literature review of national publications between 1999 to 2009 was made in the electronic databases SciELO, LILACS, PsycINFO, BVS and Google Scholar. From the 69 studies selected, 15 were excluded because they were not compatible with the research. The results showed nine themes: (1) the distance learning technology with psychological grounding, (2) affection, (3)the role of the tutor/professor, (4) psychological theories, (5) interactivity, (6) dropout, (7) reports of experiences, (8) assessment of distance training, development and education and (9) others. The topics distance education technology with psychological grounding and affection had a larger frequency in the publications. Since 2006, there was an increasing number of publications in psychology distance education, but the years of major publications were from 2008 to 2009. It is suggested that future studies expand this research including international databases.El presente estudio investigó las contribuciones de la Psicología para la Educación a Distancia – EAD. Para eso, fue realizada una revisión bibliográfica de publicaciones nacionales, entre 1999 y 2009 en las bases de datos SciELO, Lilacs, PsycINFO, BVS y Google Académico. Fueron seleccionados 69 estudios, de los cuales se excluyeron 15, por no ser compatibles con la pesquisa. Los resultados evidenciaron nueve ejes temáticos (1) tecnología educacional la distancia con fundamentos psicológicos; (2) afección; (3) papel del tutor/profesor; (4) teorías psicológicas; (5) interactividad; (6) evasión; (7) relatos de experiencias, (8) evaluación de entrenamiento, desarrollo y educación distancia y (9) otros. Los temas tecnología educacional a distancia con fundamentos psicológicos y afección obtuvieron mayor frecuencia en las publicaciones. En ese estudio se registró, también, que, aunque en ascensión desde 2006, los años de mayores publicaciones de la psicología en la educación a distancia, fueron 2008 y 2009. Se sugiere que estudios futuros amplíen esa pesquisa para incluir bases de datos internacionales

CERKL-associated retinal dystrophy: Genetics, Phenotype and Natural History

PURPOSE: To analyze the clinical characteristics, natural history, and genetics of CERKL-associated retinal dystrophy in the largest series to date. DESIGN: Multicenter retrospective cohort study. SUBJECTS: 47 patients (37 families) with likely disease-causing CERKL variants METHODS: Review of clinical notes, ophthalmic images, and molecular diagnosis from two international centres. MAIN OUTCOME MEASURES: Visual function, retinal imaging and characteristics were evaluated and correlated. RESULTS: The mean age at the first visit was 29.6 + 13.9 years and the mean follow-up time was 9.1 + 7.4 years. The most frequent initial symptom was central vision loss (40%) and the most common retinal feature was well-demarcated areas of macular atrophy (57%). Seventy percent of the participants had double-null genotypes and 64% had electrophysiological assessment. Amongst the latter, 53% showed similar severity of rod and cone dysfunction, 27% revealed a rod-cone, 10% a cone-rod, and 10% a macular dystrophy dysfunction pattern. Patients without double-null genotypes tended to have fewer pigment deposits and included a higher proportion of older patients with a relatively mild electrophysiological phenotype. Longitudinal analysis showed that over half of the cohort lost 15 ETDRS letters or more in at least one eye during the first 5 years of follow up. CONCLUSIONS: The phenotype of CERKL-retinal dystrophy is broad, encompassing isolated macular disease to severe retina-wide involvement, with a range of functional phenotypes, generally not fitting in the rod-cone/cone-rod dichotomy. Disease onset is often earlier, with more severe retinal degenerative changes and photoreceptor dysfunction, in nullizygous cases

ANTIBACTERIAL ACTIVITY OF TRIBULUS TERRESTRIS L. AGAINST ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS

أجريت الدراسة على القطبة (الحسك) Tribulus terrestris L. من العائلة الرطراطية Zygophyllaceae الذي جمع من محافظة الضالع في منطقة خوبر خلال شهر مارس 2022، وتم عمل الاستخلاص المائي والميثانولي في مختبر قسم العقاقير لكلية الصيدلة – جامعة عدن، و من ثم أجريت الدراسة على نوعين من البكتيريا أحداهما موجبة الجرام Staphylococcus aurous والأخرى سالبة الجرام Escherichia coli. أجريت التجربة الميكروبية في مختبر الأحياء الدقيقة – جامعة العلوم والتكنولوجيا حيث أجريت تجربة عاملية ذات ثلاثة عوامل (نوع المذيب، التركيز والوقت)، وكررت كل معاملة ثلاث مرات، وكانت النتائج المتحصل عليها كالتالي: أظهر المستخلص لكلا المذيبين أكبر منطقة تثبيط ضد كلا النوعين من البكتيريا و ذلك عند التراكيز العالية 400، 600 و 800 مغ/مل و كانت أفضل النتائج بعد 72 ساعة لكلا النوعين من البكتيريا، إذ أعطت طريقة الأقراص فعالية ضد بكتيريا Staphylococcus aureus، بينما كانت طريقة الحفر هي الفعالة ضد بكتيريا Escherichia coli. التداخل بين العاملين (التراكيز المستخدمة و نوع المذيب) أظهر أفضل النتائج عند المتخلص الميثانولي باستخدام طريقة الأقراص ضد بكتيريا Escherichia coli عند تركيز 200 مغ/مل و 800 مغ/مل ضد بكتيريا Staphylococcus aureus . التداخل بين العاملين (الوقت و نوع المذيب) أظهر أفضل النتائج بعد 72 ساعة في المستخلص المائي باستخدام طريقة الحفر ضد بكتيريا Escherichia coli، بينما كانت أفضل نتائج ضد بكتيريا Staphylococcus aureus بعد 72 ساعة في المستخلص الميثانولي باستخدام طريقة الأقراص. التداخل بين العاملين (التراكيز والوقت) أظهر أفضل النتائج بعد 72 ساعة عند تركيز 800 مغ/مل باستخدام طريقة الحفر ضد بكتيريا Escherichia coli، بينما أظهر أفضل النتائج ضد بكتيريا Staphylococcus aureus بعد 72 ساعة عند تركيز 400 مغ/مل باستخدام طريقة الأقراص. تشير النتائج المتحصل عليها من التداخل بين الثلاث العوامل (نوع المذيب، التراكيز والوقت) أن المستخلص الميثانولي عند تركيز 200 مغ/مل بعد 72 ساعة باستخدام طريقة الأقراص أعلى قدرة تثبيطية ضد النوع Escherichia coli، بينما المستخلص المائي عند تركيز 600 مغ/مل بعد 72 ساعة أظهر أكبر فعالية ضد النوع Staphylococcus aureus.The experiment was performed on the plant Tribulus terrestris L. which was collected from Khobar region in Al Dhale’ Governorate, Republic of Yemen on March. The extracts used (aqueous and methanol) were prepared in Lab of Pharmacognosy, Faculty of Pharmacy – Aden University. The experiment was done on two types of bacteria, one Gram negative (Escherichia coli) and one Gram positive (Staphylococcus aureus). The antimicrobial part of the experiment was carried out in the Microbiology Lab - University of Science and Technology, Aden, Yemen. The experiment was performed in triplicates, and using three factors (Type of solvent, Time and Concentrations). The results obtained were the following: The best solvent for extracting antibacterial substances was methanol in both bacteria (E. coli and S. aureus). The concentrations that produced the highest inhibition zones in E. coli were 600 and 800 mg/ml using well method, while in S. aureus the best concentrations were 400 and 600 mg /ml. The best result was obtained after 72 h using disk method on S. aureus, and using well method on E. coli. Interaction between concentrations and type of solvent showed that the best result was obtained by methanol extract using disk method at 200 mg/ml against E. coli, while the best result against S. aureus was obtained by methanol extract using disk method at 800 mg/ml. Interaction between different times and type of solvent indicated that the best result against E. coli was observed after 72h by aqueous extract using well method, while the best result against S. aureus was observed after 72h by methanol extract using disk method. Interaction between concentrations and different times showed that the best result was obtained after 72h at concentration 800mg/ml using well method against E. coli, while the best result against S. aureus was after 72h at concentration 400mg/ml using disk method. Interaction between type of solvent, concentrations and different times indicated that the best result in E. coli was observed after 72h by methanol extract at 200mg/ml using disk method, while the best result in S. aureus was observed after 72h by aqueous extract at 600mg/ml using disk method

Computational study on organochlorine insecticides extraction using ionic liquids

Insecticides pose hazardous environmental effects and can enter the food chain and contaminate water resources. Ionic liquids (ILs) have recently drawn much interest as environmentally friendly solvents and have been an efficient choice for extracting pesticides because of their outstanding thermophysical characteristics and tunable nature. In this study, ILs were screened using COSMO-RS (Conductor-like Screening Model for Real Solvents) to extract organochlorine insecticides from water at 289 K. A total of 165 ILs, a combination of 33 cations with five anions, were screened by COSMO-RS to predict the selectivity and capacity of the organochlorine insecticides at infinite dilution. The Organochlorine insecticide compounds, such as benzene hexachloride (BHC), Heptachlor, Aldrin, Gamma-Chlordane (γ-Chlordane), Endrin, and Methoxychlor are selected for this study. Charge density profiles show that Endrin and Methoxychlor compounds are strong H-bond acceptors and weak H-bond donors, while the rest of the compounds are H-bond donors with no H-bond acceptor potential. Moreover, it has been shown that ILs composed of halides and heteroatomic anions in conjunction with cations have enhanced selectivity and capacity for insecticides. Moreover, the hydrophobic phosphonium-based ILs have enhanced selectivity and capacity for insecticides. In BHC extraction, the selectivity of 1,3-dimethyl-imidazolium chloride was found to be the highest at 1074.06, whereas 2-hydroxyethyl trimethyl ammonium chloride exhibited the highest capacity being 84.0.1,3-dimethyl-imidazolium chloride exhibits the highest performance index, which is 57064.77. In addition, the ILs that have been chosen are well-recognized as environmentally friendly and very effective solvents to extract insecticides from water. As a result, this study evaluated that ILs could be promising solvents that may be further developed for the extraction of insecticides from contaminated water.This work was made possible by the support of an International Research Collaboration Co-Fund (IRCC ) grant from Qatar University , grant reference number IRCC-2022-607. Open Access funding provided by Qatar National Library . The statements made herein are solely the responsibility of the authors.Scopu