bluuebunny/crossref_metadata_2025 huggingface dataset:
Interferons as Essential Modulators of Atherosclerosis
Authors: Boshuizen Marieke C.S. , de Winther Menno P.J.
Published: May 2015

Interferons (IFNs) are key regulators of both innate and adaptive immune responses. The family of IFN cytokines can be divided into 3 main subtypes of which type I and type II IFNs are most well-defined. IFNs are known to be important mediators in atherosclerosis. Evidence from both in vitro and in vivo studies shows that the IFNs are generally proatherosclerotic. However, their role in atherosclerosis is complex, with distinct roles for these cytokines throughout different stages of the disease. In this review, we will discuss the current knowledge on the role of type I and type II IFNs in atherosclerosis development, specifically focusing on their role in endothelial activation, cell recruitment, foam cell formation, and regulation of apoptosis. Furthermore, we will discuss whether IFNs could be considered as new molecular targets for therapeutic intervention in atherosclerosis.
Molecular Mechanisms of Skeletal Muscle Atrophy in a Mouse Model of Cerebral Ischemia
Authors: Desgeorges Marine Maud , Devillard Xavier , Toutain Jérome , Divoux Didier , Castells Josiane , Bernaudin Myriam , Touzani Omar , Freyssenet Damien Gilles
Published: May 2015

Background and Purpose—

Loss of muscle mass and function is a severe complication in patients with stroke that contributes to promoting physical inactivity and disability. The deleterious consequences of skeletal muscle mass loss underline the necessity to identity the molecular mechanisms involved in skeletal muscle atrophy after cerebral ischemia.

Methods—

Transient focal cerebral ischemia (60 minutes) was induced by occlusion of the right middle cerebral artery in C57BL/6J male mice. Skeletal muscles were removed 3 days later and analyzed for the regulation of critical determinants of muscle mass homeostasis (Akt/mammalian target of rapamycin pathway, myostatin-Smad2/3 and bone morphogenetic protein-Smad1/5/8 signaling pathways, ubiquitin-proteasome and autophagy-lysosome proteolytic pathways).

Results—

Cerebral ischemia induced severe sensorimotor deficits associated with muscle mass loss of the paretic limbs. Mechanistically, cerebral ischemia repressed Akt/mammalian target of rapamycin pathway and increased expression of key players of ubiquitin-proteasome pathway (MuRF1 [muscle RING finger-1], MAFbx [muscle atrophy F-box], Musa1 [muscle ubiquitin ligase of SCF complex in atrophy-1]), together with a marked increase in myostatin expression, in both paretic and nonparetic skeletal muscles. The Smad1/5/8 pathway was also activated.

Conclusions—

Our data fit with a model in which a repression of Akt/mammalian target of rapamycin pathway and an increase in the expression of key players of ubiquitin-proteasome pathway are critically involved in skeletal muscle atrophy after cerebral ischemia. Cerebral ischemia also caused an activation of bone morphogenetic protein-Smad1/5/8 signaling pathway, suggesting that compensatory mechanisms are also concomitantly activated to limit the extent of skeletal muscle atrophy.
Racial/Ethnic Variation in Carotid Artery Revascularization Utilization and Outcomes
Authors: Wayangankar Siddharth A. , Kennedy Kevin F. , Aronow Herbert D. , Rundback John , Tafur Alfonso , Drachman Douglas , Patel Bhavin , Sivaram Chittur A. , Latif Faisal
Published: May 2015

Background and Purpose—

It is not known whether racial or ethnic disparities observed with other revascularization procedures are also seen with carotid artery stenting (CAS) and endarterectomy (CEA).

Methods—

We compared the utilization and outcomes of CAS and CEA across racial/ethnic groups within the CARE Registry between May 2007 and December 2012.

Results—

Between 2007 and 2012, of the 13 129 patients who underwent CAS, majority were non-Hispanic whites (89.3%), followed by blacks (4.4%), Hispanics (4.3%), and other groups (2.0%). A similar distribution was observed among the 10 953 patients undergoing CEA (non-Hispanic whites, 92.6%; blacks, 3.5%; Hispanics, 2.8%; and other groups, 1.1%). During this time period, a trend toward proportionate increase in CAS utilization was observed in non-Hispanic whites and other groups, whereas the opposite was observed among Hispanics and blacks. This trend persisted even when hospitals performing both CAS and CEA were exclusively analyzed. Adherence to antiplatelet and statin therapy was significantly lower among blacks post CEA. In-hospital major adverse cardiac and cerebrovascular events remained comparable across groups post CAS and CEA. At 30 days, the incidence of stroke (7.2%) and major adverse cardiac and cerebrovascular events (8.8%) was higher among blacks post CEA (
P
<0.05), after risk adjustment.

Conclusion—

During the study period, utilization of CAS and CEA was highest among non-Hispanic whites. There was a trend toward increased CAS utilization over time among non-Hispanic whites and other groups, and a trend toward increased CEA utilization among Hispanics and blacks. In-hospital major adverse cardiac and cerebrovascular events remained comparable between groups, whereas 30-day major adverse cardiac and cerebrovascular events were significantly higher in blacks.
Functional and Motor Outcome 5 Years After Stroke Is Equivalent to Outcome at 2 Months
Authors: Meyer Sarah , Verheyden Geert , Brinkmann Nadine , Dejaeger Eddy , De Weerdt Willy , Feys Hilde , Gantenbein Andreas R. , Jenni Walter , Laenen Annouschka , Lincoln Nadina , Putman Koen , Schuback Birgit , Schupp Wilfried , Thijs Vincent , De Wit Liesbet
Published: May 2015

Background and Purpose—

Recovery of patients within the first 6 months after stroke is well documented, but there has been little research on long-term recovery. The aim of this study was to analyze functional and motor recovery between admission to rehabilitation centres and 5 years after stroke.

Methods—

This follow-up of the Collaborative Evaluation of Rehabilitation in Stroke Across Europe study, included patients from 4 European rehabilitation centres. Patients were assessed on admission, at 2 and 6 months, and 5 years after stroke, using the Barthel Index, Rivermead Motor Assessment Gross Function, Leg and Trunk function, and Arm function. Linear mixed models were used, corrected for baseline characteristics. To account for the drop-out during follow-up, the analysis is likelihood-based (assumption of missingness at random).

Results—

A total of 532 patients were included in this study, of which 238 were followed up at 5 years post stroke. Mean age at stroke onset was 69 (±10 SD) years, 53% were men, 84% had ischemic strokes, and 53% had left-sided motor impairment. Linear mixed model analysis revealed a significant deterioration for all 4 outcomes between 6 months and 5 years (
P
<0.0001). Scores at 2 months were not statistically significant different from scores at 5 years after stroke. Higher age (
P
<0.0001) and increasing stroke severity on admission (
P
<0.0001) negatively affected long-term functional and motor recovery.

Conclusions—

Five-year follow-up revealed deterioration in functional and motor outcome, with a return to the level measured at 2 months. Increasing age and increasing stroke severity negatively affected recovery up to 5 years after stroke.
Punishment and Psychology in Plato’s Gorgias
Authors: Shaw J. Clerk
Published: May 2015

In the Gorgias, Socrates argues that just punishment, though painful, benefits the unjust person by removing injustice from her soul. This paper argues that Socrates thinks the true judge (i) will never use corporal punishment, because such procedures do not remove injustice from the soul; (ii) will use refutations and rebukes as punishments that reveal and focus attention on psychological disorder (= injustice); and (iii) will use confiscation, exile, and death to remove external goods that facilitate unjust action.
Aristotle’s Political Economy: Three Waves of Interpretation
Authors: Dinneen Nathan
Published: May 2015

Aristotle’s thoughts on economic matters are included in his inquiry into the nature of politics. They are certainly ancillary to his thoughts on the education requisite for excellence. Yet this ranking should not cause one to overlook Aristotle’s contributions to the field of normative political economy. To appreciate these contributions, it is helpful to look to the scholarship on Aristotle’s political economy. In this essay such an inquiry is approached through categorizing the scholarship into three stages or waves of interpretation: 1) ‘Aristotle’s Economic Thought’ (Karl Polanyi and M.I. Finely), 2) ‘Aristotle’s “Political” Economy’, (William James Booth, Abram Shulsky, Harvey C. Mansfield, Jr.), and 3) ‘Aristotle on the Best Possible Political Economy’ (Michael D. Chan, Victor Davis Hanson, and Judith Swanson). The overall goal of this essay is to provide an account of the stages by which it might be useful to think through Aristotle’s political economy.
Zeno’s Republic, Plato’s Laws, and the Early Development of Stoic Natural Law Theory
Authors: Atkins Jed W.
Published: May 2015

Recent scholarship on Stoic political thought has sought to explain the relationship between Zeno’s Republic and the concept of a natural law regulating a cosmic city of gods and human beings that is attributed to later Stoics. This paper provides a reassessment of this relationship by exploring the underappreciated influence of Plato’s Laws on Zeno’s Republic and, through Zeno, on the subsequent Stoic tradition. Zeno’s attempt to remove perceived inconsistencies in Plato’s treatment of ‘law’ and ‘nature’ established a philosophical framework that overturned the republicanism of Plato and Aristotle; this same framework established the preconditions for the cosmic city of gods and human beings regulated by natural law. Thus, the early Stoic tradition on the topic of natural law is characterized by continuity rather than by discontinuity.
Guerra com a lingoa
Authors: Windmuller-Luna Kristen
Published: May 2015

This article examines the book culture of the Jesuit mission to Ethiopia (1557–1632). Combining archival and field research, it considers the composition of the mission’s now-lost libraries, the use of books as tools of conversion, book production, and missionary engagement with Ethiopian Orthodox book culture. Furthermore, it illuminates the Jesuit reliance upon Ethiopian collaborators both to understand Orthodox texts and to produce Catholic manuscripts in the absence of a printing press. Using the personal libraries of Pedro Páez, S.J. and Afonso Mendes, S.J. as case studies, it posits that the gradual acceleration of acts performed by Jesuits upon Orthodox books—including collecting, translating, editing, and destroying—paralleled the rising aggression and cultural intolerance of the mission. Ultimately, this resulted in the expulsion and murder of the Jesuits, and the destruction of their libraries in a series of state-sanctioned book burnings that permitted a revival of Ethiopian Orthodoxy.
Pollen morphology of Sabinaria magnifica (Cryosophileae, Coryphoideae, Arecaceae)
Authors: Bogota Giovanni Raul , Hoorn Carina , Star Wim , Langelaan Rob , Banks Hannah , Galeano Gloria , Bernal Rodrigo
Published: May 2015

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera.
Seven new species expand the morphological spectrum of Haslea. A comparison with Gyrosigma and Pleurosigma (Bacillariophyta)
Authors: STERRENBURG FRITHJOF A.S. , TIFFANY MARY ANN , HINZ FRIEDEL , HERWIG WULF E. , HARGRAVES PAUL E.
Published: May 2015

Seven new Haslea species demonstrate that the genus has evolved a richer morphological repertoire than so far reported. H. feriarum sp. nov. has a valve contour suggesting an Amphora; H. staurosigmoidea sp. nov. has a sigmoid valve with a pseudostauros; H. tsukamotoi sp. nov. and the closely similar H. meteorou sp. nov. possess uniquely shaped external central raphe endings and a fully sideways-tilted internal raphe system; H. clevei sp. nov. and H. avium sp. nov. also have central raphe ending shapes not yet described in the genus; H. amicorum shows interrupted longitudinal fissures besides the continuous fissures characteristic of Haslea. A survey of the Haslea species described, for differentiation of our taxa, led to two conclusions: 1) the data in the protologue of H. indica Desikachary & Prema are spurious and 2) “Navicula” duerrenbergiana Hustedt is here transferred to the genus Haslea. The basic Haslea morphology is a sandwich-type valve, with a grate-like inner layer (here called basal layer) and an outer layer (here called tegumental layer) perforated by continuous longitudinal fissures. These two layers are shored by upright longitudinal “bulkheads”, here called saepes, seen to be perforated in the valves that permitted their observation. This morphology is closely similar to that of Gyrosigma (and Pleurosigma). The great variety of central external raphe ending patterns in Haslea, Gyrosigma and Pleurosigma is shown and discussed.
A new caruncle-bearing Limnonectes (Anura: Dicroglossidae) from northeastern Thailand
Authors: AOWPHOL ANCHALEE , RUJIRAWAN ATTAPOL , TAKSINTUM WUT , CHUAYNKERN YODCHAIY , STUART BRYAN L.
Published: May 2015

A new species of the dicroglossid frog genus Limnonectes is described from Ubon Ratchathani Province, northeastern Thailand. Limnonectes lauhachindai sp. nov. differs from its congeners by having males with a low-profiled, U-shaped caruncle with free posterior margin that completely occupies, but does not extend beyond, the interobital region. The new species is most closely related to L. gyldenstolpei and L. dabanus. Its description brings the total number of caruncle-bearing species of Limnonectes to five.
High-Elevation Precipitation Patterns: Using Snow Measurements to Assess Daily Gridded Datasets across the Sierra Nevada, California*
Authors: Lundquist Jessica D. , Abel Mimi R. , Henn Brian , Gutmann Ethan D. , Livneh Ben , Dozier Jeff , Neiman Paul
Published: May 2015

Gridded spatiotemporal maps of precipitation are essential for hydrometeorological and ecological analyses. In the United States, most of these datasets are developed using the Cooperative Observer (COOP) network of ground-based precipitation measurements, interpolation, and the Parameter–Elevation Regressions on Independent Slopes Model (PRISM) to map these measurements to places where data are not available. Here, we evaluate two daily datasets gridded at ° resolution against independent daily observations from over 100 snow pillows in California’s Sierra Nevada from 1990 to 2010. Over the entire period, the gridded datasets performed reasonably well, with median total water-year errors generally falling within ±10%. However, errors in individual storm events sometimes exceeded 50% for the median difference across all stations, and in many cases, the same underpredicted storms appear in both datasets. Synoptic analysis reveals that these underpredicted storms coincide with 700-hPa winds from the west or northwest, which are associated with post-cold-frontal flow and disproportionately small precipitation rates in low-elevation valley locations, where the COOP stations are primarily located. This atmospheric circulation leads to a stronger than normal valley-to-mountain precipitation gradient and underestimation of actual mountain precipitation. Because of the small average number of storms (<10) reaching California each year, these individual storm misses can lead to large biases (~20%) in total water-year precipitation and thereby significantly affect estimates of statewide water resources.
Assessment of the High-Resolution Rapid Refresh Model’s Ability to Predict Mesoscale Convective Systems Using Object-Based Evaluation
Authors: Pinto James O. , Grim Joseph A. , Steiner Matthias
Published: May 2015

An object-based verification technique that keys off the radar-retrieved vertically integrated liquid (VIL) is used to evaluate how well the High-Resolution Rapid Refresh (HRRR) predicted mesoscale convective systems (MCSs) in 2012 and 2013. It is found that the modeled radar VIL values are roughly 50% lower than observed. This mean bias is accounted for by reducing the radar VIL threshold used to identify MCSs in the HRRR. This allows for a more fair evaluation of the model’s skill at predicting MCSs. Using an optimized VIL threshold for each summer, it is found that the HRRR reproduces the first (i.e., counts) and second moments (i.e., size distribution) of the observed MCS size distribution averaged over the eastern United States, as well as their aspect ratio, orientation, and diurnal variations. Despite threshold optimization, the HRRR tended to predict too many (few) MCSs at lead times less (greater) than 4 h because of lead time–dependent biases in the modeled radar VIL. The HRRR predicted too many MCSs over the Great Plains and too few MCSs over the southeastern United States during the day. These biases are related to the model’s tendency to initiate too many MCSs over the Great Plains and too few MCSs over the southeastern United States. Additional low biases found over the Mississippi River valley region at night revealed a tendency for the HRRR to dissipate MCSs too quickly. The skill of the HRRR at predicting specific MCS events increased between 2012 and 2013, coinciding with changes in both the model physics and in the methods used to assimilate the three-dimensional radar reflectivity.
Being a ‘suspect community’ in a post 9/11 world – The impact of the war on terror on Muslim communities in Australia
Authors: Cherney Adrian , Murphy Kristina
Published: May 2015

The suspect community thesis has been used to explain how and why Muslims have become a stigmatised minority, subject to increased state surveillance and public discourse that constructs Muslims as a potential terrorist threat. Breen-Smyth (2014) argues that a suspect community is generated through national or state security policies and reproduced and reinforced by societal responses and social practices. This influences how Muslims perceive themselves as a suspect community and influences their support for counter-terrorism efforts. This paper will explore the ‘experiential consequences’ of Muslims being stigmatised and labelled as a suspect community and the perceptions this has generated among Muslims living in Australia. We examine how Muslims have reacted to being defined as a terrorist threat and the coping mechanisms they adopt to defend their religious beliefs given Islam is seen by authorities, the media and the public as justifying violence. This paper will explore these issues by reporting results from focus group data collected from Muslims living in Sydney, Brisbane and Melbourne ( N = 104 participants in total). Results illustrate how being defined as a suspect community influences the appraisals Muslims have of themselves, their faith, their community and Australian authorities. Implications for counter-terrorism policies are also identified.
Harassment, stalking, threats and attacks targeting New Zealand politicians: A mental health issue
Authors: Every-Palmer Susanna , Barry-Walsh Justin , Pathé Michele
Published: May 2015

Objective:

Due to the nature of their work, politicians are at greater risk of stalking, harassment and attack than the general population. The small, but significantly elevated risk of violence to politicians is predominantly due not to organised terrorism or politically motivated extremists but to fixated individuals with untreated serious mental disorders, usually psychosis. Our objective was to ascertain the frequency, nature and effects of unwanted harassment of politicians in New Zealand and the possible role of mental illness in this harassment.

Methods:

New Zealand Members of Parliament were surveyed, with an 84% response rate ( n = 102). Quantitative and qualitative data were collected on Parliamentarians’ experiences of harassment and stalking.

Results:

Eighty-seven percent of politicians reported unwanted harassment ranging from disturbing communications to physical violence, with most experiencing harassment in multiple modalities and on multiple occasions. Cyberstalking and other forms of online harassment were common, and politicians felt they (and their families) had become more exposed as a result of the Internet. Half of MPs had been personally approached by their harassers, 48% had been directly threatened and 15% had been attacked. Some of these incidents were serious, involving weapons such as guns, Molotov cocktails and blunt instruments. One in three politicians had been targeted at their homes. Respondents believed the majority of those responsible for the harassment exhibited signs of mental illness.

Conclusion:

The harassment of politicians in New Zealand is common and concerning. Many of those responsible were thought to be mentally ill by their victims. This harassment has significant psychosocial costs for both the victim and the perpetrator and represents an opportunity for mental health intervention.
Assessing the significance of women in combat roles
Authors: Trisko Darden Jessica
Published: May 2015

What should we know about the roles of women in armed conflicts? I review the existing literature on women’s roles in regular and irregular conflicts to identify gaps in our understanding of the significance of female combatants. I draw on contemporary and historical cases of women’s combat participation across world regions and, in so doing, I challenge existing assumptions about the limits of women’s participation in armed conflict. Examining women as a group and expecting conflict to affect this group in predictable and easily identifiable ways only reinforces existing assumptions about women and war. To understand the range of motivations underlying women’s decisions to fight or to not fight, we should give greater attention to opportunity structures and other social conditions rather than simply assuming that women have different incentives than men.
Design of an Industrial Distribution System for Reliability
Authors: Sharma J.
Published: May 2015

A comparative study of various types of industrial distribution systems is made from reliability considerations. A two-state mathematical model is used for analytical prediction of system reliability. A method is discussed to maximise reliability of industrial distribution system by utilising redundant components. The computational procedure is illustrated by an example.
An Algorithm for Transients in a Transmission System with Non-Linear Resistive Element
Authors: Tripathy S. C. , Khan M. Yusuf
Published: May 2015

An algorithm closely following Bergeron's method has been developed to calculate transients in a transmission system with step input. The transmission system includes a transmission line, a transformer, a load, and a thyrite arrester. It is shown how an exact solution can be obtained with the help of this algorithm when a resistive non-linearity is presented in the system.
GaAs Liquid Epitaxy-A Useful Aid in Teaching Electronic Materials Technology
Authors: Hartnagel H. L.
Published: May 2015

It is shown that a liquid—epitaxy system for GaAs is relatively easily set up as a useful means of teaching electronic materials technology. The equipment required, essential aspects of operating such a system, the assessment methods for the single-crystal layers produced and a brief review of the possible new device developments are presented. Some experimental results are given which are obtained by such an educational system.
A New Introductory Electronics Laboratory at Nottingham
Authors: Pugh Alan
Published: May 2015

An original, introductory approach to the teaching of electronic circuits in the laboratory is described, based on the amplifier as the fundamental building block. Students are first required to assemble two amplifiers, on printed cards, without the need for a complete understanding of the circuit details. These amplifiers are then used for various experiments.
An Indirect Method for Solving Non-Linear Optimal Control Problems in Power Systems-Part 2
Authors: Malik O. P. , Mukhopadhyay B. K. , Subramaniam P.
Published: May 2015

This paper describes the application of quasilinearization algorithm and its various modifications to solve the non-linear optimal control problems in power systems. Results obtained by this indirect numerical technique are compared to those obtained by other, direct methods. It is shown that a proposed hybrid approach, in conjunction with the continuation method, can be considered as an effective iterative procedure for most practical problems in power systems.
Maxwell Stress and Force on Current-Carrying Conductor
Authors: Majmudar Harit
Published: May 2015

This article contains a new derivation of the formula, BLi, for a force on a current-carrying conductor placed in a magnetic field. This derivation uses the concept of Maxwell stress. The conductor is assumed to be a rectangular bar with negligible width, but with finite height and finite length. The bar is placed in a magnetic field that is parallel to its height and perpendicular to its length. The force on the conductor is determined by finding compressive stresses on the two surfaces parallel to the field. This is accomplished by recognizing that flux density at the two surfaces is modified by the current in the bar.
Transformer Project
Authors: Greenwood P.
Published: May 2015

The paper describes a teaching experiment which was performed in a degree course at an institute of technology in an underdeveloped country. A project was followed in the laboratory which integrated aspects of a 25 kVA distribution transformer construction, design and testing with lectures. All the tests were of industrial standard.
Continuous Assessment and Student Motivation in Management Studies
Authors: Carpenter Norman
Published: May 2015

Experiments are described which suggest that the allocation of substantial marks for continuous assessment in relation to those attainable in formal examinations can induce more consistent study habits leading to better attendance at lectures, more regular submission of exercises and coursework submissions of better quality.
Electronic Buffer Memories
Authors: Philokyprou G. , Halatsis C. C.
Published: May 2015

The paper covers the classification and functional description of electronic buffer memories (i.e., buffers made of semiconductor store and logic). The classification is made according to the servicing policies imposed upon the input stream. Within each class various buffering schemes are examined taking into consideration the input stream characteristics, speed and buffer size requirements, types of memory and circuit technology. Application areas of the buffers, such as computer channels and information distribution systems are cited.
The Current-Voltage Relationships Due to Transit-Time Effects in an Intrinsic Semiconductor
Authors: Lam Y. W.
Published: May 2015

The analysis is based on the small-signal theory whereby all variables are linearized to a d.c. component and an a.c. component at the fundamental frequency. A general equation is then obtained for the a.c. terminal voltage in terms of the a.c. current and transit time. A special case of practical importance is also considered in which the electric field throughout the semiconductor is sufficiently high so that carriers move at their saturation velocity.
Electricity in a General Engineering Degree Course
Authors: Fuller A. J. Baden
Published: May 2015

The electrical content of the syllabus of a unified engineering degree course is analysed in order to show its relevance to students who wish to become electrical or electronic engineers.
Alpha, Delta and Zero Components for the Analysis of Three-Phase Systems
Authors: Narayana C. L. , Radhakrishna C.
Published: May 2015

This paper presents a set of new substitute variables (α, δ, 0), components for the analysis of 3-phase circuits and machines. Their application to various types of imbalances when studied on a Network Analyser is given. Advantages of these components over others are mentioned.
Graphical Methods for the Analysis of Linear and Nonlinear Circuits
Authors: Madani Henry
Published: May 2015

Graphical methods are developed for the analysis and design of electronic circuits, with inherent accuracies superior to those obtainable from small-signal equivalent circuits. Among the typical examples outlined are the emitter follower, the common-emitter with external emitter resistance, the Darlington Pair, the cascode amplifier, and various diode and transistor clipping circuits. Once mastered, the methods can be extended to other and more complex circuits, and to transient analysis.
A Method of Introducing Computer-Aids into an Undergraduate Course in Electronics
Authors: Daruvala D.J.
Published: May 2015

The paper describes how, by providing a comprehensive set of subroutines, methods of computer-aided analysis may be incorporated fully in an undergraduate course in Electrical Engineering.
The Errors in Marking Examination Scripts in Electronic Engineering
Authors: McVey P. J.
Published: May 2015

Independent multiple-marking of 186 examination scripts, and non-independent double marking of 766 scripts, are reported. The impression of close agreement given by the latter is apparently spurious for the independent marking showed much greater discrepancies. Though between-marker correlations were high, the range of marks awarded to a script was often disturbingly large.
Power Electronics in an Undergraduate Curriculum
Authors: Oghanna W.
Published: May 2015

This paper establishes the need for a course in Solid-State Power Electronics in the undergraduate electrical engineering curriculum. The appropriate level and duration of a suitable course are discussed and contact hours are recommended from experience with an existing course. A suggested course outline is provided.
A Low-Frequency Waveform Sampling Unit
Authors: Basak A.
Published: May 2015

A unit has been designed to enable a pen recorder to record low frequency waveforms ranging from 20 Hz to 20 KHz, using the technique of Time Sampling. The whole unit has been built quite inexpensively and the components were readily available in the laboratory.
Determination of Overvoltages in Transmission Line Terminations Using a Physical Model
Authors: Binns D. F. , Habibollahi H.
Published: May 2015

Switching transients have been studied for a short line terminated by an inductor. Resonance with the third harmonic of the transient voltage in the line can produce a peak of 5 pu in the termination, while the fifth harmonic can produce 4.2 pu. Source inductance reduces these voltages appreciably.
An Electromagnetic Force Apparatus — A Note
Authors: Padmanabhan K.
Published: May 2015

A simple apparatus is described for students to measure electromagnetic force, calculate flux, reluctance of composite circuit and plot the B-H curves of magnetic materials. Only an ammeter and spring balance are handled and the results are comparable to more involved measurements.
Synchronous Machine Performance with Automatic Voltage Regulator
Authors: O'Kelly D.
Published: May 2015

The undergraduate treatment of steady state synchronous machine performance by power/rotor angle characteristics is extended to include a physical concept of the operation of a machine with automatic voltage regulator control.
La Relativite Restreinte Dans L'Enseignement De La Theorie Electromagnetique Aux Ingenieurs
Authors: Hoefer Wolfgang J. R.
Published: May 2015

In recent years, many renowed physicists have emphasized relativity when introducing their students to electromagnetic theory. This is an excellent way to present electromagnetic concepts not only to future physicists but also to future electrical engineers. The present paper outlines some difficulties in the classical approach that may be overcome by using concepts of special relativity.
A Graphical Method for the Solution of D.C. Network Problems
Authors: Thomas G.
Published: May 2015

A general method of solving d.c. network problems by constructing graphically the electrical characteristics of the circuit components is developed. This graphical technique, which has not previously been fully utilized, is shown to be an alternative to the well-known algebraic techniques. The method is illustrated with standard network examples.
ConformalTransformations in the Presence of Field Components along a Third Axis — Part I
Authors: Schinzinger Roland
Published: May 2015

The presence of field components along a third axis does not prevent the application of planar conformal transformation techniques. Some complications are introduced in that the characteristics of the media are altered in the model, but in many cases this poses no major difficulties.
Interdisciplinary Courses in Control Engineering
Authors: Athani Vithal V.
Published: May 2015

This paper describes the interdisciplinary courses in Control Engineering being developed at IIT - Bombay. The need for such interdisciplinary courses is explained in the beginning, and the three basic interdisciplinary courses in Control Engineering are discussed. Then are described advanced level and specialized courses offered by various departments.
Aspects of Electronics Engineering Teaching in Papua New Guinea
Authors: Kormilo S. R. , King R. W.
Published: May 2015

In this paper we attempt to identify the major problems encountered in teaching Electronics and Communications Engineering at the Papua New Guinea University of Technology. We describe how we are attempting to make our presentation of the course material more relevant to the needs of the students.
Introducing Symmetrical Components with a Visual Aid on the Overhead Projector
Authors: Thomas D. H.
Published: May 2015

A configuration of clear plastic gears demonstrates phasor addition of a negative set in variable phase to a fixed positive sequence. Overlays are suggested for presenting symmetrical component theory without mathematics, whilst indicating applications. The description indicates the method of construction.
Q
Authors: Rose-Innes A. C.
Published: May 2015

A method is described of presenting Q so that its basic significance can be understood. The point is made that Q is a parameter of any device able to store energy. It can then easily be seen why it is applicable to both resonant circuits and single non-resonant components.
Analogue Measurement of Linear Velocity
Authors: Basak A. , Rossiter P. L. , Overshott K. J.
Published: May 2015

A non-contact method of measuring the linear displacement and velocity of a moving body with time has been constructed and tested. The method is particularly applicable for laboratory measurements and uses photoelectric devices spaced along the track which are activated by a light source on the moving body.
Conformal Transformations in the Presence of Field Components along a Third Axis — Part 2
Authors: Schinzinger Roland
Published: May 2015

Examples are given to show that the simplicity in configuration attainable by conformal transformation can outweigh the modifications which are required in the characteristics of the medium when field components in a third dimension are present.
An Improved Right-Hand Rule of Electro-Magnetism
Authors: Haider A. K.
Published: May 2015

The improved rule uses the right-hand and a pencil held normal to the stretched palm. The rule is based upon fundamental electro-magnetic principles, emphasizes the reversibility of motor-generator operation, and demonstrates the interaction between the parameters of a motor or of a generator.
Interfacing an Existing Analogue Installation to a Mini-Computer
Authors: Deighton S. A. , Preece C.
Published: May 2015

A simply implemented digital-analogue computer interface is described. The system allows the study of digital control of plant to be carried out experimentally using high level language programming readily understood by undergraduates. Considerable use is made of Varian-supplied ADAPTS system software.
Stability of Load Frequency Control System for Interconnected Power Systems with Governor Dead-Band Nonlinearity
Authors: Tripathy S. C. , Saha N.
Published: May 2015

The domain separation method is used for an appropriate choice of parameters on the basis of a linear model of load frequency control. A Popov plot is then used to check if the system is stable with governor dead-band nonlinearity.
Designing the Electrical Distribution System of a Teaching Laboratory
Authors: Tavner P.J.
Published: May 2015

The article has particular relevance to designing electrical engineering laboratories in developing countries and discusses some of the problems of planning the power circuit distribution system. Tables of power supplies, outlets and stabilisation equipment suitable for a laboratory are presented with a comprehensive bibliography.
Considerations in Developing University Microcircuit Fabrication Laboratories
Authors: Gaylord T.K.
Published: May 2015

The fabrication of microcircuits can be efficiently pursued at a university if a clear philosophy is maintained to make the fabrication facility as useful and as economical as possible. The questions of what equipment should be purchased and how sophisticated it should be must be answered in a logical way.
Duality in Switching Functions
Authors: Bell E. C. , Rhodes R. L.
Published: May 2015

Various aspects of duality, in switching algebra and mapping techniques, are examined. It is shown that familiarity with the principles of duality, as applied to switching networks, leads to a deeper understanding of switching theory and can give improvements in manipulative methods.
A Note on the Teaching of the Stochastic Digital to Analogue Converter
Authors: Ritchey A.
Published: May 2015

A brief article describing a technique of introducing students to the stochastic digital to analogue converter, particularly those with no background knowledge of random signal theory.
The Education, Training and Career Development of Professional Engineers in the UK and its Influence on Women Engineers
Authors: Laverick E
Published: May 2015

This paper discusses the position of women vis-a-vis a professional engineering career in the U.K. It is concluded that degree courses and post-graduate training schemes are well suited to the woman engineer and that activities in the field of career development could also help her after a career ‘break’.
Design and Performance of a Delta Modulator
Authors: Cheung W. N.
Published: May 2015

The article describes an undergraduate experiment on communication systems using delta modulation. The circuitry involved may be assembled in any electronics laboratory and the experiment serves to demonstrate to students the process of encoding analogue signals into digital form for transmission.
The Effect of ‘Paper Error’ on the Reliability of Examinations
Authors: James C.
Published: May 2015

An investigation is reported in which twenty-four students in electronics and physics sat two different three-hour examinations covering the same syllabus on consecutive days under conventional examination conditions. These papers were later re-marked and the results suggest that inter-paper variation is much larger than inter-marker variation.
O ΦΥΣIKOΣ KOΣMOΣ
Authors: Maritsas D. G.
Published: May 2015

A brief article describes a monthly magazine published by the Hellenic Physical Society, in Greece, and aimed at the 13 to 18 year old grammar school student.
Measurement of Flux in a Ceramic Permanent Magnet of Complex Shape
Authors: Basak A.
Published: May 2015

The flux measurement in a permanent magnet by producing a relative movement between it and a search coil is restricted to its simple shape. The almost-linear normal demagnetization characteristics of most ceramic magnet materials enable employment of a novel method to determine the flux distribution in complex shaped magnets.
Some Notes on Winding Analysis and the Measurement of Machine Parameters
Authors: Battersby G. A. , Mansell A. D.
Published: May 2015

The paper considers the relationship between winding harmonics and slot numbers and the reason for differences in the performance of machines when connected in star or delta. An equivalent circuit which can be used to calculate the magnetising current for an irregular winding is then discussed and finally a means of measuring the harmonic flux content is described.
Simple Calculation of Critical Clearing Time
Authors: Fox B.
Published: May 2015

A direct method for the calculation of critical clearing time is presented. The method is only applicable to the most severe fault condition. However, this is the most important condition, as it determines the maximum combined relay and circuit breaker operating time for maintenance of synchronism under all fault conditions.
Analytic Techniques for Designing Digital Non-Recursive Filters
Authors: Attikiouzel J. , Bennett R.
Published: May 2015

Non-iterative analytic techniques are presented which employ orthogonal polynomials in the design of linear phase non-recursive digital/filters. Pass band and stop band transformations are desired to approximate an ideal low pass digital filter. Also the economization of power series technique is employed to derive near optimum responses.
Introduction to Microprocessor Systems — Part 3
Authors: Best P. J. , Depledge P. G. , Escuder M. A. , Powner E. T.
Published: May 2015

The paper considers the development of microprocessor systems from a first-time user's viewpoint, particular attention being paid to the utilisation of the development aids described in the previous article. Several applications developed at U.M.I.S.T. are described to highlight the versatility of microprocessor-based designs.
A First-Year Electrical Engineering Laboratory to Satisfy all Requirements?
Authors: Berthoud L. A.
Published: May 2015

This paper describes a first-year laboratory programme which seeks to satisfy several educational aims. The programme comprises three sections, formal experiments, project and ‘advanced’ experiments, each of which is described in detail. The reasons for this structure are then discussed together with initial impressions of its success.
On Teaching a RC Active Filter Course with the Aid of a Digital Computer
Authors: Sánchez-Sinencio Edgar , Rajasekaran Periagaram K.
Published: May 2015

An outline of a specific course on active RC filters is presented. We describe briefly the use of computer simulation as a valuable aid to the laboratory experiments. Highlights include operational amplifier modelling and a novel filter structure that uses the roll-off characteristic of the operational amplifier.
The Analysis of Complex Control Problems: Part 2 — The Graphical Solution of Higher Order Systems
Authors: Arlett P. L. , Vasudeva K. S.
Published: May 2015

A method for the solution of second and higher order systems which may contain non-linear or time-variant elements is presented. These elements may be included in the forward or feedback paths of multi-loop systems as suggested in Part 1 of this contribution. No advanced mathematics are required.
An Original Method for Predicting the Terminal Voltage of an Alternator for a Fixed Excitation by the Two Axis Theory
Authors: Knight G. J. , Haddock L.
Published: May 2015

The paper discusses a method, which, to the best of the authors' knowledge is original, for the prediction of the terminal voltage of a three-phase alternator for a given excitation at any value of load current and power factor, by graphical means. Results obtained by using the method are compared with those obtained by direct experimental measurement.
Sabbatical Leave — A Personal Account
Authors: Hartley M. G.
Published: May 2015

The advantages to both the visitor and the hosts, of sabbatical leave in another country are discussed, and practical advice is offered to anyone contemplating such leave.
A Digital Proportional Position Control Scheme
Authors: Subbayyan R. , Vaithilingam M. C. , Lakshmanna G.
Published: May 2015

This paper describes the principles and fabrication details of a digital proportional position controller using a synchro resolver as position transducer. The digital controller can be readily attached to existing analog position servo demonstration units available in educational laboratories.
The Logical Basis of Electrical Circuit Theory
Authors: Budrikis Z. L.
Published: May 2015

Two assumptions underlie circuit theory: infinite speed of propagation of force and existence at all times of equilibrium in matter. The theory is therefore essentially of static states. Voltages across all circuit components, including inductors, transformers, generators and others, are differences in potential, traceable to Coulomb forces and obeying Poisson's equation.
The Analysis of Complex Control Problems: Part 3 — The Graphical Technique Applied to Systems Containing Transport Delays
Authors: Arlett P. L. , Vasudeva K. S.
Published: May 2015

The use of the graphical technique for the solution of complex and non-linear feedback problems has previously been explained. This contribution further extends the method to the solution of systems containing transport delays. No advanced mathematics is required and examples of systems with transport delays in forward and feedback paths are included.
The Electric Field in Maxwell's Equations
Authors: Budrikis Z. L.
Published: May 2015

The field E in Maxwell's equation curl E = – δB/δ t is limited to induction and Coulomb force. It does not extend to all phenomena that are included in E of Ohm's law, J = σE. Maxwell's equation would need another term to account for additional vorticity of the E in Ohm's law.
The Use of a Graphics Terminal as an Aid to Teaching Fields
Authors: Butler P. , Martin I.
Published: May 2015

The article describes a programme that has been written to aid the teaching of fields. The programme utilises a graphics terminal, on which lines of equipotential around given configurations are given.
Computation of Electric Fields: Part 1 — Determination of Electrical Resistance of Notched Rectangular Laminar Conductors
Authors: McEwan P. M. , Askew J. A.
Published: May 2015

A novel numerical method, for use with a digital computing routine to determine the resistance of notched, laminar rectangular shapes, is given. This method can be used with conventional field mapping methods or experimental measurements to enhance student understanding of Laplacian fields.
Aspects of Applied Statistics Underemphasized in Electrical Metrology
Authors: Spriggs K. R.
Published: May 2015

The academic emphasis given to aspects of statistics in electrical metrology is questioned. It is proposed that textbook, and consequently lecture course treatment of statistics falls short in equipping the engineer for practical measurement analysis. Curriculum modifications are suggested whereby practical error specification, error combination techniques, small sample analysis and curve fitting are adopted as objectives.
Application-Oriented Ray Theory
Authors: Censor Dan
Published: May 2015

This is a tutorial presentation of the subject of ray theory as provided for third-year students of electrical engineering. The concepts of the eikonal and dispersion equation, group velocity, wave packet, Fermat's principle and the ray equations are introduced. This is essential for students majoring in electromagnetic engineering.