a reliable quantitative structure retention relationship (qsrr) study has been evaluated to predict the retention indices (ris) of a broad spectrum of compounds, namely 118 non-linear, cyclic and heterocyclic terpenoids (both saturated and unsaturated), on an hp-5ms fused silica column. a principal component analysis showed that seven compounds lay outside of the main cluster. after elimination...

Until quite recently, theories on thermophoresis of particles predicted very low thermophoretic velocities of metal particles in liquids. This prediction was based on the understanding that the very high thermal conductivities of metals relative to most liquid media resulted in quite low temperature gradients across the metal particle thereby leading to low net force on the particle. In this pa...

Many academics and practitioners have reiterated the importance of online customer retention in order to ensure long-term profitability. For this reason, a number of studies have identified various means and ends of developing customer retention with a greater emphasis on creating customer loyalty. However, retaining customers, especially in Internet, is very difficult because of the low search...

The present study investigated the relative contributions of experiential and ability factors to second language (L2) passage comprehension and L2 vocabulary retention. Participants included a cross section of 99 adult learners of Spanish as a foreign language enrolled in beginning through advanced level university Spanish courses. Participants completed a standardized reading proficiency test ...

Metabolite profiling in biomarker discovery, enzyme substrate assignment, drug activity/specificity determination, and basic metabolic research requires new data preprocessing approaches to correlate specific metabolites to their biological origin. Here we introduce an LC/MS-based data analysis approach, XCMS, which incorporates novel nonlinear retention time alignment, matched filtration, peak...

In situ modification of bacterial cellulose (BC) allows structural and morphological tuning which determines the crucial properties such as water absorption/retention rheological behaviour. This work reports effect in carried out by adding two biopolymers Agar Chitosan to standard culture media for synthesis. The agar modified BC (Agar-BC) form a network with reduced pore volume, much denser ne...

Taking a memory test not only assesses what one knows, but also enhances later retention, a phenomenon known as the testing effect. We studied this effect with educationally relevant materials and investigated whether testing facilitates learning only because tests offer an opportunity to restudy material. In two experiments, students studied prose passages and took one or three immediate free-...

An experiment was performed to investigate the effects of practice and spacing on retention of Japanese-English vocabulary paired associates. The relative benefit of spacing increased with increased practice and with longer retention intervals. Data were fitted with an activation-based memory model, which proposes that each time an item is practiced it receives an increment of strength but that...

The present research investigated whether test-enhanced learning can be used to promote transfer. More specifically, 4 experiments examined how repeated testing and repeated studying affected retention and transfer of facts and concepts. Subjects studied prose passages and then either repeatedly restudied or took tests on the material. One week later, they took a final test that had either the ...