Practical considerations regarding power factor for nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThe choice of LC compensator may be constrained by the availability of manufacturers units. To account for this, the capacitor values are chosen from among standard values and for each value the transmission losses is minimized, or power factor is maximized, or transmission efficiency is maximized. The global minimum or maximum is obtained by scanning all local minims or maxims. The performance of the obtained compensator is discussed by means of numerical examples

LC compensators for power factor correction of nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEA method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples

Mirror neuron activation in children with developmental coordination disorder: A functional MRI study.

The aim of this study was to reveal cortical areas that may contribute to the movement difficulties seen in children with Developmental Coordination Disorder (DCD). Specifically, we hypothesized that there may be a deficit in the mirror neuron system (MNS), a neural system that responds to both performed and observed actions. Using functional MRI, 14 boys with DCD (x¯=10.02 years±1.28, range=8.33-11.17 years) and 12 typically developing controls (x¯=10.10 years±1.16, range=8.02-12 years) were scanned observing, executing and imitating a finger sequencing task using their right hand. Cortical activations of mirror neuron regions, including posterior inferior frontal gyrus, ventral premotor cortex, anterior inferior parietal lobule and superior temporal sulcus were examined. Children with DCD had decreased cortical activation mirror neuron related regions, including the precentral gyrus and inferior frontal gyrus, as well as in the posterior cingulate and precuneus complex when observing the sequencing task. Region of interest analysis revealed lower activation in the pars opercularis, a primary MNS region, during imitation in the DCD group compared to controls. These findings provide some preliminary evidence to support a possible MNS dysfunction in children with DCD

A novel pathway producing dimethylsulphide in bacteria is widespread in soil environments

The volatile compound dimethylsulphide (DMS) is important in climate regulation, the sulphur cycle and signalling to higher organisms. Microbial catabolism of the marine osmolyte dimethylsulphoniopropionate (DMSP) is thought to be the major biological process generating DMS. Here we report the discovery and characterisation of the first gene for DMSP-independent DMS production in any bacterium. This gene, mddA, encodes a methyltransferase that methylates methanethiol (MeSH) and generates DMS. MddA functions in many taxonomically diverse bacteria including sediment-dwelling pseudomonads, nitrogen-fixing bradyrhizobia and cyanobacteria, and mycobacteria, including the pathogen Mycobacterium tuberculosis. The mddA gene is present in metagenomes from varied environments, being particularly abundant in soil environments, where it is predicted to occur in up to 76% of bacteria. This novel pathway may significantly contribute to global DMS emissions, especially in terrestrial environments, and could represent a shift from the notion that DMSP is the only significant precursor of DMS

Huntingtin gene repeat size variations affect risk of lifetime depression

Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect depression risk in the general population. Using binary logistic regression, we assessed the association between HTT CAG repeat size and depression risk in two well-characterized Dutch cohorts─the Netherlands Study of Depression and Anxiety and the Netherlands Study of Depression in Older Persons─including 2165 depressed and 1058 non-depressed persons. In both cohorts, separately as well as combined, there was a significant non-linear association between the risk of lifetime depression and HTT CAG repeat size in which both relatively short and relatively large alleles were associated with an increased risk of depression (β = −0.292 and β = 0.006 for the linear and the quadratic term, respectively; both P < 0.01 after adjustment for the effects of sex, age, and education level). The odds of lifetime depression were lowest in persons with a HTT CAG repeat size of 21 (odds ratio: 0.71, 95% confidence interval: 0.52 to 0.98) compared to the average odds in the total cohort. In conclusion, lifetime depression risk was higher with both relatively short and relatively large HTT CAG repeat sizes in the normal range. Our study provides important proof-of-principle that repeat polymorphisms can act as hitherto unappreciated but complex genetic modifiers of depression

Digital and Non-Digital Feedback Modes in Private Higher Institution: Students’ Perception.

The use of effective and high-quality instructional feedback has been identified as a key element of quality teaching and learning. The is a major change in the provision of instructional feedback in higher education due to the rapid growth of internet strategy resulting in different forms of feedback modes provided by lecturers. Instructional feedback is generally provided in digital modes and non-digital modes through two various mediums known as text-based feedback comments (electronic annotations, marking sheet or rubric, handwritten) and verbal feedback comments (face-to-face and digitally recorded). These feedback modes are used to monitor student learning in response to instruction and provide prompts to students to confirm, refine, or clarify their understandings. Even though there is recognition of the significant role and value that feedback plays in student learning, very little is understood about how students perceive the feedback they receive on their work. So, this study aims to investigate students’ perceptions of the uses of digital and non-digital feedback modes in Kolej Poly-Tech MARA Alor Setar (KPTMAS). This study employed a quantitative approach through an online survey and the survey items adapted from Ryan, Henderson &amp; and Phillips (2019). The population of the study consisted of Kolej Poly-Tech MARA Alor Setar students. Hopefully, these findings enhance our understanding of the students' preferences in the use of feedback modes in higher education. Henderson &amp; Phillips (2019). The population of the study consisted of Kolej Poly-Tech MARA Alor Setar students. Hopefully, these findings enhance our understanding of the students' preferences in the use of feedback modes in higher education

A Study on the Use of Online Learning System (OLeS) among Academic Staffs in Private Higher Education Institutions.

There is a significant transformation for higher education to confront intense competition, enhance the academic program to meet the challenges of this competition and develop new teaching and learning strategies to fulfil the demand of the global marketplace. Furthermore, the rapid growth of internet-based innovations has resulted in changes in teaching approaches, and learning development manifested in different forms of e-learning. Even the traditional method such as tutorials and face-to-face tutorial lecturers are still strongly dominant, and higher education intensively invests in learning technologies to facilitate greater quality enhancements in students learning experiences. This study was conducted to explore the uses of the online learning system (OLeS) in the teaching and learning process among lecturers in Kolej Poly-Tech Mara Alor Setar. This study employed a  qualitative approach; semistructured interviews and online learning records. The population of study consisted of 41 lecturers and was conducted November in 2018. Thematic analysis was used for semi-structured interview data, whereas Descriptive Analysis was utilized to analyse the online learning records. Through the thematic analysis; three main themes were revealed such as management encouragement and support, lecturers’ positive attitudes toward the use of online learning and the benefits of online learning towards students. Overall, the result showed positive attitudes among lecturers toward the uses of online learning due to the management efforts and perceive usefulness. Hopefully, these findings enhance our understanding of the uses of online learning in higher education, indicating several issues to consider while implementing online learning in teaching and learning

Antifungal activity of a novel chromene dimer

The activity on Aspergillus spp. growth and on ochratoxin A production of two novel chromene dimers (3) was evaluated. The results of the bioassays indicate that the chromene dimer 3a inhibited mycelia growth by approximately 50% (EC50) at 140.1 μmol L−1 for A. niger, 384.2 μmol L−1 for A. carbonarius, 69.1 μmol L−1 for A. alliaceus and 559.1 μmol L−1 for A. ochraceus. When applied at concentrations of 2 mmol L−1, 3a totally inhibited the growth of all Aspergillus spp. tested. Furthermore, ochratoxin A production by A. alliaceus was reduced by about 94% with a 200 μmol L−1 solution of this compound. A moderate inhibitory effect was observed for the analogous structure 3b on ochratoxin A production but not in mycelia growth. No inhibition was registered for compounds 2a and 2b, used as synthetic precursors of the dimeric species 3.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/ 11228/2002