A Current Source Inverter Fed Induction Motor Drive with Power Factor Angle Control Using Microprocessor

This paper describes a method of adjusting the stator power factor angle for the control of an induction motor fed from a current source inverter (CSI) based on the concept of space vectors (or park vectors). It is shown that under steady state, if the torque angle is kept constant over the entire operating range, it has the advantage of keeping the slip frequency constant. This can be utilized to dispose of the speed feedback and simplify the control scheme for the drive, such that the stator voltage integral zero crossings alone can be used as a feedback for deciding the triggering instants of the CSI thyristors under stable operation of the system. A closed-loop control strategy is developed for the drive based on this principle, using a microprocessor-based control system and is implemented on a laboratory prototype CSI fed induction motor drive.

A New Three-Phase Current Source Inverter with Flexible PWM Capability

A new three-phase current source inverter topology is presented, consisting of three single-phase bridge inverters connected in series and feeding the isolated windings of a standard three-phase induction motor. Because a current zero in one phase now does not affect the others, it enables the implementation of a wide range of current PWM patterns for the reduction and selective elimination of torque pulsations. Furthermore, this system allows for very fast control of the fundamental load current through the use of sinusoidal PWM, a method that was not possible to implement on existing inverter topologies.

Rice molecular breeding laboratories in the genomics era: Current status and future considerations

Using DNA markers in plant breeding with marker-assisted selection (MAS) could greatly improve the precision and efficiency of selection, leading to the accelerated development of new crop varieties. The numerous examples of MAS in rice have prompted many breeding institutes to establish molecular breeding labs. The last decade has produced an enormous amount of genomics research in rice, including the identification of thousands of QTLs for agronomically important traits, the generation of large amounts of gene expression data, and cloning and characterization of new genes, including the detection of single nucleotide polymorphisms. The pinnacle of genomics research has been the completion and annotation of genome sequences for indica and japonica rice. This information-coupled with the development of new genotyping methodologies and platforms, and the development of bioinformatics databases and software tools-provides even more exciting opportunities for rice molecular breeding in the 21st century. However, the great challenge for molecular breeders is to apply genomics data in actual breeding programs. Here, we review the current status of MAS in rice, current genomics projects and promising new genotyping methodologies, and evaluate the probable impact of genomics research. We also identify critical research areas to "bridge the application gap" between QTL identification and applied breeding that need to be addressed to realize the full potential of MAS, and propose ideas and guidelines for establishing rice molecular breeding labs in the postgenome sequence era to integrate molecular breeding within the context of overall rice breeding and research programs.

A New PWM Control Method for Three-Phase Autosequentially Commutated Current Source Inverters

A new current pulsewidth modulation (PWM) method is presented which uses the principle of creating zero three-phase currents at selected instants of time, through which the load current harmonic content can be controlled along with the magnitude of its fundamental content. This gives rise to reduction of motor torque ripples through the selection of suitable PWM patterns and a fast current control in the inverter by varying the pulsewidths of the PWM pattern. Under this new PWM mode of operation, the autosequentially commutated inverter (ASCI) circuit can be modified easily so that a higher number of pulses can be accomodated within a half-cycle, compared to the normal ASCI circuit. The experimental oscillograms verify the effectiveness of the new PWM method.

The ACA effect: Examining how current affairs programs shape victim understandings and responses to online fraud

In recent years, numerous current affairs stories on online fraud victimisation have been broadcast on Australian television. These stories typically feature highly organised, international ‘sting’ operations, in which alleged offenders are arrested and investigated by law enforcement. These portrayals of police responses influence the expectations that some online fraud victims have about how their individual cases will be handled by law enforcement. Based on interviews with 80 online fraud victims, this article argues that a narrow media portrayal of online fraud by television current affairs programs — termed the ‘ACA effect’ — informs victims’ understandings of online fraud and their responses to it. In particular, current affairs programs influence what victims of online fraud expect from police. The article further demonstrates that current affairs programs present themselves as de facto law enforcement agencies, to which victims who receive an unsatisfactory response from police might turn. Overall, the article highlights the importance of current affairs programs portraying a more realistic image of official responses to online fraud.

Development of a vaccine for Chlamydia trachomatis: Challenges and current progress

Chlamydia trachomatis remains an enigmatic bacterial pathogen with no vaccine yet available to treat human ocular and genital tract infections caused by tissue-tropic serovars of the organism. Globally, it is the leading cause of preventable blindness as well as the leading cause of bacterial sexually transmitted infections. The pathogen has a range of virulence factors that enable it to successfully evade both the innate and adaptive immune system of the host. The host immune system, although protective, paradoxically is also associated closely with the pathologies of trachoma and pelvic inflammatory disease – disease sequelae of some chlamydial infections and reinfections in some genetically susceptible hosts. In this review, we focus on what is known currently about the pathogenesis of ocular and genital infections caused by this mucosal pathogen. We also discuss novel insights into the pathogenesis of infections caused by the genital and ocular serovars of C. trachomatis, including a discussion of both pathogen and host factors, such as the human microbiota at these mucosal sites as well as the current immunological challenges facing vaccine development. Finally, we discuss the current progress toward development of a vaccine against C. trachomatis. A wide range of recombinant protein antigens are being identified and, hence, are available for vaccine trials. A plasmid-free live strain has recently been produced and evaluated in the mouse (Chlamydia muridarum) and monkey (C. trachomatis) models. The data for ocular infections in the monkey model was particularly encouraging, although the path to regulatory approval of a live vaccine is still uncertain. While still a major challenge, vaccines for ocular and genital C. trachomatis infections are looking more promising.

NOx Reduction and Desorption Studies Under Electric Discharge Plasma Using a Simulated Gas Mixture: A Case Study on the Effect of Corona Electrodes

In this study, reduction and desorption of oxides of nitrogen (NOx) were conducted using an electrical discharge plasma technique. The study was carried out using a simulated gas mixture to explore the possibility of re-generation of used adsorbents by a nonthermal plasma desorption technique. Three different types of corona electrodes, namely, pipe, helical wire, and straight wire, were used for analyzing their effectiveness in NOx reduction/desorption. The pipe-type corona electrode exhibited a nitric oxide (NO) conversion of 50%, which is 1.5 times that of the straight-wire-type electrode at an energy density of 175J/L. The helical-wire-type corona electrode exhibited a NOx desorption efficiency almost 4 times that of the pipe-type electrode,indicating the possibility that corona-generated species play a crucial role in desorption.

Reassessing the earthquake hazard in Kerala based on the historical and current seismicity

Given the lack of proper constraints in understanding earthquake mechanisms in the cratonic interiors and the general absence of good quality database, here we reassess the seismic hazard in the province of Kerala, a part of the aEuro cent stable continental interioraEuro cent, based on an improved historical and instrumental database. The temporal pattern of the current seismicity suggests that > 60% of the microtremors in Kerala occurs with a time lag after the peak rainfall, indicating that hydroseismicity may be a plausible model to explain the low-level seismicity in this region. Further, an increment in overall seismicity rate in the region in the recent years is explained as due to increased anthropogenic activities, which includes changes in hydrological pathways as a consequence of rapid landscape changes. Our analyses of the historical database eliminate a few events that are ascribed to this region; this exercise has also led to identification of a few events, not previously noted. The improved historical database essentially suggests that the central midland region is more prone to seismic activity compared to other parts of Kerala. This region appears to have generated larger number of significant earthquakes; the most prominent being the multiple events (doublets) of 1856 and 1953, whose magnitudes are comparable to that of the 2000/2001 (central Kerala) events. Occurrences of these historical events and the recent earthquakes, and the local geology indicative of pervasive faulting as shown by widely distributed pseudotachylite veins suggest that the NNW-SSE trending faults in central midland Kerala may host discrete potentially active sources that may be capable of generating light to moderate size earthquakes. The frequency of earthquakes in central Kerala evident from the historical database requires that the seismic codes stipulated for this region are made mandatory.

Self-rating scales in the assessment of current and childhood symptoms of attention deficit hyperactivity disorder in adults

Objective: Attention deficit hyperactivity disorder (ADHD) is a life-long condition, but because of its historical status as a self-remitting disorder of childhood, empirically validated and reliable methods for the assessment of adults are scarce. In this study, the validity and reliability of the Wender Utah Rating Scale (WURS) and the Adult Problem Questionnaire (APQ), which survey childhood and current symptoms of ADHD, respectively, were studied in a Finnish sample. Methods: The self-rating scales were administered to adults with an ADHD diagnosis (n = 38), healthy control participants (n = 41), and adults diagnosed with dyslexia (n = 37). Items of the self-rating scales were subjected to factor analyses, after which the reliability and discriminatory power of the subscales, derived from the factors, were examined. The effects of group and gender on the subscales of both rating scales were studied. Additionally, the effect of age on the subscales of the WURS was investigated. Finally, the diagnostic accuracy of the total scores was studied. Results: On the basis of the factor analyses, a four-factor structure for the WURS and five-factor structure for the APQ had the best fit to the data. All of the subscales of the APQ and three of the WURS achieved sufficient reliability. The ADHD group had the highest scores on all of the subscales of the APQ, whereas two of the subscales of the WURS did not statistically differ between the ADHD and the Dyslexia group. None of the subscales of the WURS or the APQ was associated with the participant's gender. However, one subscale of the WURS describing dysthymia was positively correlated with the participant's age. With the WURS, the probability of a correct positive classification was .59 in the current sample and .21 when the relatively low prevalence of adult ADHD was taken into account. The probabilities of correct positive classifications with the APQ were .71 and .23, respectively. Conclusions: The WURS and the APQ can provide accurate and reliable information of childhood and adult ADHD symptoms, given some important constraints. Classifications made on the basis of the total scores are reliable predictors of ADHD diagnosis only in populations with a high proportion of ADHD and a low proportion of other similar disorders. The subscale scores can provide detailed information of an individual's symptoms if the characteristics and limitations of each domain are taken into account. Improvements are suggested for two subscales of the WURS.

The Link Between Medicaid and the Individuals with Disabilities Education Act (IDEA): Recent History and Current Issues

[From Summary] As a condition of accepting funds under IDEA, public schools must provide special education and related services necessary for children with disabilities to benefit from a public education. Generally, states can finance only a portion of these costs with federal IDEA funds. Medicaid, the federal-state program that finances medical and health services for the poor, can cover IDEA required health-related services for enrolled children as well as related administrative activities (e.g., outreach for Medicaid enrollment purposes, medical care coordination/monitoring). However, the link between IDEA and Medicaid has not been seamless. Despite written federal guidance, schools have a difficult time meeting the myriad complex reimbursement rules applicable to all Medicaid participating providers. According to federal investigations and congressional hearings, Medicaid payments to schools have sometimes been improper. The President’s FY2007 budget proposal would prohibit federal Medicaid reimbursement for IDEA-related school-based administration and transportation costs. This report will be updated.

Effects of increasing neuromuscular electrical stimulation current intensity on cortical sensorimotor network activation: A time domain fNIRS study

Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O₂Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O₂Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O₂Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.

Current CAPE-15: A measure of recent psychotic-like experiences and associated distress

Aim Psychotic-like experiences (PLEs) are common in young people and are associated with both distress and adverse outcomes. The Community Assessment of Psychic Experiences-Positive Scale (CAPE-P) provides a 20-item measure of lifetime PLEs. A 15-item revision of this scale was recently published (CAPE-P15). Although the CAPE-P has been used to assess PLEs in the last 12 months, there is no version of the CAPE for assessing more recent PLEs (e.g. 3 months). This study aimed to determine the reliability and validity of the current CAPE-P15 and assess its relationship with current distress. Method A cross-sectional online survey of 489 university students (17–25 years) assessed lifetime and current substance use, current distress, and lifetime and 3-month PLEs on the CAPE-P15. Results Confirmatory factor analysis indicated that the current CAPE-P15 retained the same three-factor structure as the lifetime version consisting of persecutory ideation, bizarre experiences and perceptual abnormalities. The total score of the current version was lower than the lifetime version, but the two were strongly correlated (r = .64). The current version was highly predictive of generalized distress (r = .52) and indices that combined symptom frequency with associated distress did not confer greater predictive power than frequency alone. Conclusion This study provided preliminary data that the current CAPE-P15 provides a valid and reliable measure of current PLEs. The current CAPE-P15 is likely to have substantial practical utility if it is later shown to be sensitive to change, especially in prevention and early intervention for mental disorders in young people.

Can exploring natural recovery from substance misuse in psychosis assist with treatment? A review of current research

Substance misuse in people with psychosis presents significant problems, but trials of treatments to address it show little sustained advantage over control conditions. An examination of mechanisms underpinning unassisted improvements may assist in the refinement of co-morbidity treatments. This study reviewed existing research on natural recovery from substance misuse in people with psychosis. To address this issue, a systematic search identified only 7 articles that fulfilled the criteria. Their results suggest that people with psychosis report similar reasons to change as do non-psychotic groups, although they did not clarify whether the relative frequencies or priority orders were the same. Differences involved issues relating to the disorder and the functional problems faced by this group: receipt of treatment for mental health difficulties, worsening of mental health difficulties, and homelessness. The current research on reasons for change in people with psychosis is sparse and has significant limitations, and as yet it offers little inspiration for new treatments. A more fertile source may prove to be a detailed investigation of successful substance control strategies that are used in self-management by this group.

Weed management in wide-row cropping systems: a review of current practices and risks for Australian farming systems.

Growing agricultural crops in wide row spacings has been widely adopted to conserve water, to control pests and diseases, and to minimise problems associated with sowing into stubble. The development of herbicide resistance combined with the advent of precision agriculture has resulted in a further reason for wide row spacings to be adopted: weed control. Increased row spacing enables two different methods of weed control to be implemented with non-selective chemical and physical control methods utilised in the wide inter-row zone, with or without selective chemicals used on the on-row only. However, continual application of herbicides and tillage on the inter-row zone brings risks of herbicide resistance, species shifts and/or changes in species dominance, crop damage, increased costs, yield losses, and more expensive weed management technology.