bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary central nervous system posttransplantation lymphoproliferative disorder after heart and lung transplantation
Authors: Gifford G. , Fay K. , Jabbour A. , Ma D. D.
Published: May 2015

Primary central nervous system posttransplantation lymphoproliferative disorder (PCNS‐PTLD) is uncommon, especially after heart or lung transplantation. Database analysis from a single heart and lung transplantation centre and a literature review pertaining to PCNS‐PTLD was performed. In this study, the prevalence of PCNS‐PTLD was 0.18% after heart and/or lung transplants. Of 1674 transplants, three cases of PCNS‐PTLD developed 14 months, 9 years and 17 years posttransplant, and all were Epstein–Barr virus driven malignancies. Literature review of the topic revealed predominantly retrospective studies, with most reported cases after renal transplantation. The overall survival is poor, and it may be improved by early diagnosis and treatment. There are no published guidelines on the management of PCNS‐PTLD; immune‐chemotherapy in conjunction with reduction of immune suppression is preferred based on available evidence.
The Effect of Rainfall on Migration from Mexico to the United States
Authors: Puente Gerónimo Barrios , Perez Francisco , Gitter Robert J.
Published: May 2015

There has been very little work on the impact of rainfall on migration from Mexico or even elsewhere. We use satellite data from NASA to examine the effect of the lagged level of rainfall relative to an area's historical average, on migration from small Mexican communities to the United States. Controlling for the level of education, proportion married, and historic migration levels, we find higher levels of rainfall significantly reduce Mexican migration to the United States and a 20 percentage point higher-than-normal level of rainfall leads to a predicted 10.3 percent decrease in migration.
The Investigations of the Pr, Gd, Si–N Doping, and Phosphor Curvature Effects on the Performances of YAG‐Based WLEDs
Authors: Chiang Chung‐Hao , Tsai Hung‐Yi , Kuo Hung‐Yi , Lin Han‐Yu , Chu Sheng‐Yuan
Published: May 2015

The effect of the phosphor curvature in the range 0.1766–0.2589 mm−1 on the luminous efficacy of Y2.95Al5O12:0.05Ce3+ (YAG)‐based white‐light‐emitting diodes (WLEDs) was investigated at the similar correlated color temperature (CCT) of ~6300 K by tuning the concentration of YAG phosphors in the phosphor layer ranging from 7.5 to 15 wt%. It was found that both the luminous efficacy and luminous power increased monotonically with the increasing curvature. The luminous efficacy (=82.4 lm/W) and luminous power (=297.85 mW) of the YAG‐based WLED at the preferable phosphor curvature of 0.2589 mm−1 were 19.44% and 17.36%, respectively, higher than those at the curvature of 0.1766 mm−1 under 350 mA. This finding reveals that the surface curvature of phosphor layers is a critical factor which cannot be ignored for the investigation of the light output of phosphor‐converted WLEDs. Moreover, the color rendering index (CRI) enhancement of YAG‐based WLED with substitution of Y2.94Al5O12:0.05Ce3+, 0.01Pr3+ (YPrAG), Y2.45Gd0.5Al5O12:0.05Ce3+ (YGdAG), and Y2.95Al4.8Si0.2O11.8N0.2:0.05Ce3+ (YAlSiON) for YAG were assessed under the same phosphor curvature of 0.2589 mm−1 and the similar CCT ~6350 K. Taking the luminous efficacy, preparation cost of phosphors, and CRI into consideration, we suggest that the YGdAG is a preferable candidate for replacing the YAG for use in WLEDs among the four kinds of phosphors. Compared with the YAG (7.5 wt%)‐based WLED, the YGdAG (7 wt%)‐based WLED exhibited an improved CRI, less preparation cost of phosphors, and the acceptable reduction in luminous efficacy under 350 mA.
A New Closed‐Form Model for Solid‐State Sintering Kinetics
Authors: Missiaen Jean‐Michel , Lebrun Jean‐Marie
Published: May 2015

The aim of this work was to revisit the two‐sphere model of solid‐state sintering kinetics to make it consistent with the morphological evolution of the particle contacts during most of the sintering process. Mass transport equations for solid‐state sintering are written in a closed‐form. The usual simplifications of tangent or secant spheres are avoided and the true evolution of the neck geometry is taken into account, depending on the relative weight of densifying / nondensifying mechanisms. Finite difference methods are used to compute the evolution of geometrical parameters and of the shrinkage rate as a function of time and temperature. The model combines the usual mechanisms of volume, surface, and grain‐boundary diffusion as well as vapor transport. The ratio of concave to convex surfaces is deduced from neck growth and from the packing coordination number. A smooth transition from the classical first stage to the intermediate stage of sintering, where curvature gradients have vanished at the particle surface, is obtained. The same model can then be applied to describe sintering kinetics until pore closure. This model providing a realistic evolution of the contact morphology makes it possible to analyze the competition between densifying and nondensifying mechanisms throughout the early and intermediate stages of sintering. The competition between lattice diffusion and vapor transport or surface diffusion is thus analyzed.
What Do Liberal Democratic States Owe the Victims of Disasters? A Rawlsian Account
Authors: Voice Paul
Published: May 2015

Is there a principled way to understand what liberal democratic states owe, as a matter of justice, to the victims (survivors) of disasters? This article shows what is normatively special and distinctive about disasters and argues for the view that there are substantial duties of justice for liberal democratic states. The article rejects both a libertarian and a utilitarian approach to this question and, based on broadly Rawlsian principles, argues for a ‘political definition’ of disasters that is concerned with the restoration of citizens' dignity and their capacities for effective citizenship.
Hobbesian Right to Healthcare
Authors: Courtland Shane D.
Published: May 2015

Over the last few years we have had a debate regarding the role of government in providing healthcare. There has been a question as to whether or not the state's proper role requires protection of its subjects from the calamities associated with a lack of healthcare. In this article, I will argue that straightforward Hobbesian principles require the state to provide healthcare. It might seem odd (or, at the very least, anachronistic) that such a positive right can be justified by a philosopher who famously conceives of individuals as motivated by self‐interest. Nonetheless, Hobbes's political theory provides the framework for such a right.
Is weight gain associated with the incidence of periodontitis? A systematic review and meta‐analysis
Authors: Nascimento Gustavo G. , Leite Fábio R.M. , Do Loc G. , Peres Karen G. , Correa Marcos B. , Demarco Flávio F. , Peres Marco A.
Published: May 2015

Aim

This study aimed to conduct a systematic review assessing the effects of weight gain on the incidence of periodontitis in adults.

Methods

Electronic searches in four databases were performed up to and including February 2015. Only prospective longitudinal studies assessing the association between weight gain and the incidence of periodontitis in adults were eligible to be included in this study. All studies should state a clear description of nutritional status (Body Mass Index; Waist Circumference) as well as the case definition of periodontitis. Pooled relative risks (RR) for becoming overweight and obese on the incidence of periodontitis were estimated by meta‐analysis. Quality was assessed with the Newcastle–Ottawa scale for cohort studies.

Results

Five articles were included in this review and meta‐analysis with 42,198 subjects enrolled. Subjects who became overweight and obese presented higher risk to develop new cases of periodontitis (RR 1.13; 95%CI 1.06–1.20 and RR 1.33 95%CI 1.21–1.47 respectively) compared with counterparts who stayed in normal weight.

Conclusions

A clear positive association between weight gain and new cases of periodontitis was found. However, these results are originated from limited evidence. Thus, more studies with longitudinal prospective design are needed.
Strategy of health information seeking among physicians, medical residents, and students after introducing digital library and information technology in teaching hospitals of Iran
Authors: kahouei Mehdi , Alaei Safollah , Shariat Panahi Sohaila Sadat Ghazavi , Zadeh Jamileh Mahdi
Published: May 2015

Objectives

It is important for physicians, medical students and health care organizations of developing countries to use reliable clinical information in order to deliver the best practice. Therefore, health sector of Iran endeavored to encourage physicians and medical students to integrate research findings into practice since 2005. Several educational interventions in the areas of information technology and databases were performed. Digital library was introduced in the teaching hospitals. The purpose of this study was to investigate whether these interventions increased the use of evidence‐based health information resources among physicians, medical residents and students.

Methods

This descriptive study involved 315 physicians, assistants and medical students in affiliated hospitals of Semnan University of medical sciences in 2013.

Results

A total 52.9% of physicians and 79.5% of medical residents and students always used patient data. 81.3% of physicians and 67.1% of medical residents and students reported using their own experiences, 26.5% of physicians and 16.9% of medical residents and students always used databases such as PubMed and MEDLINE for patient care.

Conclusion

Our results revealed that in spite of providing educational and technical infrastructures for accomplishment of research utilization in medical education, the study subjects often identified and used what they regarded as reliable and relevant information from sources that do not truly represent the best evidence that is available.
Comparative imaging of European eels (Anguilla anguilla) for the evaluation of swimbladder nematode (Anguillicoloides crassus) infestation
Authors: Frisch K , Davie A , Schwarz T , Turnbull JF
Published: May 2015

This study compares diagnostic imaging tools in detecting the parasitic swimbladder nematode Anguillicoloides crassus in Anguilla anguilla (L.) and focuses on ultrasound in an attempt to develop a non‐destructive, field diagnostic test. Ultrasound use could allow the parasite to be diagnosed without decreasing the number of critically endangered European eels through post‐mortem. In the preliminary study, eels were examined with computed radiography, computed tomography, magnetic resonance imaging, 14 MHz high‐end ultrasound and 5 MHz low‐end portable ultrasound, and the results were compared with post‐mortem findings. This ultrasound scanning technique did not produce any promising results. A second batch of eels was examined using the same high‐end and low‐end ultrasounds, but employing a different scanning technique and comparing the results with post‐mortem. This second study, scanning along the midline from below, allowed for the detection of anomalies associated with moderately infected animals. None of the eels used in this study were severely infected; thus, no conclusions can be made regarding the use of ultrasound in those animals. Overall, it was found that none of the techniques were useful in diagnosing mildly infected individuals; therefore, no single diagnostic imaging tool is sensitive enough to replace post‐mortem for definite diagnosis.
Testate amoeba Rhogostoma minus Belar, 1921, associated with nodular gill disease of rainbow trout, Oncorhynchus mykiss (Walbaum)
Authors: Dyková I , Tyml T
Published: May 2015

The case study targeted to determine the aetiology of nodular gill disease (NGD) of farmed rainbow trout. The methods included microscopical examination of gill material in fresh, culturing of isolated organisms, histology, transmission electron microscopy and molecular biology identification. The results revealed an intravital colonization of fish gills by the testate amoeba Rhogostoma minus Belar, 1921. Rhogostoma infection was found in all fish examined microscopically (15/15); in contrast, naked amoebae related to fully developed NGD lesions were found in minority of these fish (5/15). They belonged to four genera, Acanthamoeba, Vermamoeba, Naegleria and Vannella. Results presented in this study contribute to the mosaic of findings that contrary to amoebic gill disease of marine fish turn attention to the possibility of the heterogeneous, multi‐amoeba‐species and multifactorial aetiology of NGD.
Programmed cell death in seeds of angiosperms
Authors: López‐Fernández María Paula , Maldonado Sara
Published: May 2015

During the diversification of angiosperms, seeds have evolved structural, chemical, molecular and physiologically developing changes that specially affect the nucellus and endosperm. All through seed evolution, programmed cell death (PCD) has played a fundamental role. However, examples of PCD during seed development are limited. The present review examines PCD in integuments, nucellus, suspensor and endosperm in those representative examples of seeds studied to date.
Using the Unfolding Case Study in Midwifery Education
Authors: Carr Katherine Camacho
Published: May 2015

One of the challenges in teaching clinicians is helping health care provider students, including midwives, develop the critical thinking and clinical decision‐making skills needed for various situations encountered in practice. Health care provider students need to master the required core knowledge and skills but also need to assess, analyze, judge, decide on action, act, and evaluate their actions. Lecture‐heavy classroom teaching, which is usually delivered separately from clinical experiences in health care education, focuses on knowledge acquisition, often leaving knowledge application to trial and error. Case studies are commonly used by faculty with a problem‐based learning approach, which is more analytic but sometimes static. The unfolding case study presents students with a patient scenario that changes over time and allows for discussion; lecture points as needed; and decision making as the situation or condition changes, reflecting what happens in real‐life clinical practice. The use of the unfolding case study moves health care provider education from fact‐based lecturing to situation‐based discussion and decision making as a person's condition or situation changes. Use of the unfolding case facilitates collaborative learning, covers necessary content, and assists students to think beyond the facts and use their clinical imagination. Unfolding case studies require students to begin to grasp the nature of a clinical situation and adjust interventions as the clinical situation unfolds. Steps in developing and using an unfolding case study for midwifery students are presented, including 2 examples.

This article is part of a special series of articles that address midwifery innovations in clinical practice, education, interprofessional collaboration, health policy, and global health.
Sensing and surviving hypoxia in vertebrates
Authors: Jonz Michael G. , Buck Leslie T. , Perry Steve F. , Schwerte Thorsten , Zaccone Giacomo
Published: May 2015

Surviving hypoxia is one of the most critical challenges faced by vertebrates. Most species have adapted to changing levels of oxygen in their environment with specialized organs that sense hypoxia, while only few have been uniquely adapted to survive prolonged periods of anoxia. The goal of this review is to present the most recent research on oxygen sensing, adaptation to hypoxia, and mechanisms of anoxia tolerance in nonmammalian vertebrates. We discuss the respiratory structures in fish, including the skin, gills, and air‐breathing organs, and recent evidence for chemosensory neuroepithelial cells (NECs) in these tissues that initiate reflex responses to hypoxia. The use of the zebrafish as a genetic and developmental model has allowed observation of the ontogenesis of respiratory and chemosensory systems, demonstration of a putative intracellular O2 sensor in chemoreceptors that may initiate transduction of the hypoxia signal, and investigation into the effects of extreme hypoxia on cardiorespiratory development. Other organisms, such as goldfish and freshwater turtles, display a high degree of anoxia tolerance, and these models are revealing important adaptations at the cellular level, such as the regulation of glutamatergic and GABAergic neurotransmission in defense of homeostasis in central neurons.
The Partisan Battle Over College Student Voting: An Analysis of Student Voting Behavior in Federal, State, and Local Elections*
Authors: Ardoin Phillip J. , Bell C. Scott , Ragozzino Michael M.
Published: May 2015

Objective

We aim to test the hypothesis that college students provide Democratic candidates with greater electoral support and whether this varies among federal, state, and local elections. We also test whether college students mobilized by presidential campaigns are more likely to abstain from voting for state and local elections.

Methods

To examine these questions, we employed OLS and difference‐of‐means tests to analyze the distribution of votes cast in competitive elections for the November 2008 elections in 86 precincts located on 42 college campuses across five states as compared to the distribution of votes cast in noncollege precincts. College precincts were identified by representatives from each community's local Board of Elections.

Results

In line with conventional wisdom, the results of the analyses indicate Democratic candidates for federal offices do consistently receive greater electoral support from precincts located on college campuses as compared to noncollege precincts. However, the analyses of state and local elections highlight substantial variation in the level of support that Democratic candidates receive from precincts located on college campuses. Moreover, we found many college students in 2008 cast their ballots for Obama, but chose not to participate in lower‐level elections.

Conclusion

Republican fears regarding college students turning small towns on their heads via the ballot box are not supported by our analyses. On average, students vote more democratically than nonstudents but they are also more likely to simply choose not to vote for local candidates. By and large, they come to the polls to vote for national offices, not local ones.
Wear Analysis of Two Revolute Joints With Clearance in Multibody Systems
Authors: Li Pei , Chen Wei , Li Desheng , Yu Rufei , Zhang Wenjing
Published: May 2015

The wear of multiple joints with clearance is one of the main impacts on the life of mechanical systems while very limited study has been done on this subject. To be different with many existed researches focused on the dynamic analysis of multibody systems with multiple clearance joints, the wear of two revolute joints with clearance in multibody systems is analyzed in this paper by coupling dynamics with tribology. Based on a planar slider crank mechanism with two clearance joints, it is observed that the clearance sizes nonlinearly influence the wear depths of the two joints with clearance. Meanwhile, an appropriate relationship between the two joints' clearance sizes can significantly decrease the wear of the joints, which would greatly improve the system life. Both the independent and interactive influences of the two joints with clearances on the wear are investigated in this paper. The relation equations of the two clearances obtained in this work will significantly decrease the wear of the two clearance joints.
A Low-Noise Biopotential Amplifier with an Optimized Noise Efficiency Factor
Authors: Li Yang-Guo , Haider Mohammad Rafiqul , Massoud Yehia
Published: May 2015

Implantable wireless neural recording microsystems have demonstrated their efficacies in neuroscience studies in the past decades. However, with the advances of neurobiology, higher sensitivity and higher precision neural recording microsystems are becoming the critical need. A biopotential amplifier is the first stage of a neural recording microsystem, the performance of which decides the signal-to-noise ratio and the power dissipation of each recording-channel. In this paper, we present a low-noise biopotential amplifier with a noise efficiency factor (NEF) optimized closer to the theoretical limit of a folded cascode structure. A high transconductance input nMOSFET pair is designed to guarantee a low input-referred noise. A self-biased scheme comprising a weak positive feedback and a strong negative feedback is employed to further enhance the transconductance. By optimizing the noise performance while maintaining the NEF value close to the theoretical limit, a very low input-referred noise and a higher power-noise efficiency are achieved in our design. Using a standard 0.13-μm CMOS process, the proposed amplifier achieves an input-referred noise of 1.98 μVrms at the expense of 7.5 μW power, corresponding to a NEF of 2.31. The gain of the proposed amplifier is 40.84 dB at a -3 dB bandwidth from 6.65 Hz to 9.38 kHz.
Intersection homology of linkage spaces
Authors: Schütz Dirk
Published: May 2015

We consider the moduli spaces [Formula: see text] of a closed linkage with [Formula: see text] links and prescribed lengths [Formula: see text] in [Formula: see text]-dimensional Euclidean space. For [Formula: see text] these spaces are no longer manifolds generically, but they have the structure of a pseudomanifold.

We use intersection homology to assign a ring to these spaces that can be used to distinguish the homeomorphism types of [Formula: see text] for a large class of length vectors in the case of [Formula: see text] even. This result is a high-dimensional analogue of the Walker conjecture which was proven by Farber, Hausmann and the author.
A critical review of mechanisms regulating remote preconditioning-induced brain protection
Authors: Meller Robert , Simon Roger P.
Published: May 2015

Remote preconditioning (rPC) is the phenomenon whereby brief organ ischemia evokes an endogenous response such that a different (remote) organ is protected against subsequent, normally injurious ischemia. Experiments show rPC to be effective at evoking cardioprotection against ischemic heart injury and, more recently, neuroprotection against brain ischemia. Such is the enthusiasm for rPC that human studies have been initiated. Clinical trials suggest rPC to be safe (phase II trial) and effective in reducing stroke incidence in a population with high stroke risk. However, despite the therapeutic potential of rPC, there is a large gap in knowledge regarding the effector mechanisms of rPC and how it might be orchestrated to improve outcome after stroke. Here we provide a critical review of mechanisms that are directly attributable to rPC-induced neuroprotection in preclinical trials of rPC.
On the Secular Requirement
Authors: Agnafors Marcus
Published: May 2015

It is often claimed that a democratic state ought to be secular, a claim labeled here as the secular requirement. The claim is regularly treated as axiomatic by scholars and intellectuals. In the present paper, the secular requirement is challenged, and an extensive critique of the five most frequent arguments used in its support is offered. It is argued that the foundation of the secular requirement is much weaker than is commonly perceived, and that a secular state may not always be warranted.
The History of Jesuit Libraries in Croatia
Authors: Šapro-Ficović Marica , Vegh Željko
Published: May 2015

The purpose of this study is to provide a historical overview of the Jesuit libraries in Croatia from their foundation to the present. The first known libraries were at Jesuit high schools, called “colleges,” established during the seventeenth century. This article deals with foundation of libraries at the Jesuit colleges in Zagreb, Varaždin, Požega, Rijeka, and Dubrovnik, emphasizing their role supporting education and the dissemination of knowledge. These libraries were witness to a strong influence of Jesuits colleges on the spiritual, educational, and intellectual life of many Croats. Highlighted in this respect is the famous library of the Jesuit school in Dubrovnik (Collegium Ragusinum). After the suppression of Jesuit order in 1773, the colleges were closed, and their libraries scattered and plundered. Nevertheless, many books survived. Portions of the collections of the former Jesuit colleges are today an invaluable part of the patrimony of the largest Croatian libraries.
The genus Picris (Asteraceae) in southern Italy: contribution to its systematic knowledge
Authors: Astuti Giovanni , Roma-Marzio Francesco , Peruzzi Lorenzo
Published: May 2015

In southern Italy two species of Picris occur: the widespread P. hieracioides subsp. hieracioides and the endemic P. scaberrima. The latter is still lacking any karyological knowledge, it is imperfectly known as concerns cypselae morphology and its name requires typification. Thus, the name Picris scaberrima is here lectotypified and a map summarizing its distribution is presented. In addition, new data concerning cypselae morphology and karyology of the topotype population of P. scaberrima and of a nearly co-occurring population of P. hieracioides subsp. hieracioides are provided.
Ultrastructure and taxonomic position of Cymbella latestriata Pantocsek (Bacillariophyta)
Authors: Buczkó Krisztina , Ognjanova-Rumenova Nadja , Wojtal Agata Z. , Stenger-Kovács Csilla
Published: May 2015

A rare Neogene species, Cymbella latestriata, was studied by light and scanning electron microscopy. Cymbella latestriata was found to have apical pore fields on both apices, although these are simple, very small. Because of the presence of apical pore fields APF the transfer of this species to the genus Cymbopleura is not justified as previously was suggested by Krammer. Thus, the study confirms Pantocsek’s original assignment of the taxon as Cymbella latestriata.
Sensitivity of Precipitation Statistics to Resolution, Microphysics, and Convective Parameterization: A Case Study with the High-Resolution WRF Climate Model over Europe
Authors: Pieri Alexandre B. , von Hardenberg Jost , Parodi Antonio , Provenzale Antonello
Published: May 2015

We explore the impact of different resolutions, convective closures, and microphysical parameterizations on the representation of precipitation statistics (climatology, seasonal cycle, and intense events) in 20-yr-long simulations over Europe with the regional climate Weather Research and Forecasting (WRF) Model. The simulations are forced in the period 1979–98, using as boundary conditions the ERA-Interim fields over the European region. Special attention is paid to the representation of precipitation in the Alpine area. We consider spatial resolutions ranging from 0.11° to 0.037°, allowing for an explicit representation of convection at the highest resolution. Our results show that while there is a good overall agreement between observed and modeled precipitation patterns, the model outputs display a positive precipitation bias, particularly in winter. The choice of the microphysics scheme is shown to significantly affect the statistics of intense events. High resolution and explicitly resolved convection help to considerably reduce precipitation biases in summer and the reproduction of precipitation statistics.
Measuring Turbulent Kinetic Energy Dissipation at a Wavy Sea Surface
Authors: Sutherland Peter , Melville W. Kendall
Published: May 2015

Wave breaking is thought to be the dominant mechanism for energy loss by the surface wave field. Breaking results in energetic and highly turbulent velocity fields, concentrated within approximately one wave height of the surface. To make meaningful estimates of wave energy dissipation in the upper ocean, it is then necessary to make accurate measurements of turbulent kinetic energy (TKE) dissipation very near the surface. However, the surface wave field makes measurements of turbulence at the air–sea interface challenging since the energy spectrum contains energy from both waves and turbulence over the same range of wavenumbers and frequencies. Furthermore, wave orbital velocities can advect the turbulent wake of instrumentation into the sampling volume of the instrument. In this work a new technique for measuring TKE dissipation at the sea surface that overcomes these difficulties is presented. Using a stereo pair of longwave infrared cameras, it is possible to reconstruct the surface displacement and velocity fields. The vorticity of that velocity field can then be considered to be representative of the rotational turbulence and not the irrotational wave orbital velocities. The turbulent kinetic energy dissipation rate can then be calculated by comparing the vorticity spectrum to a universal spectrum. Average surface TKE dissipation calculated in this manner was found to be consistent with near-surface values from the literature, and time-dependent dissipation was found to depend on breaking.
Celebrating the Accomplishments of Others
Authors: Conoley Collie W. , Vasquez Elisa , Bello Beatriz Del Carmen , Oromendia Mercedes Fernández , Jeske Daniel R.
Published: May 2015

Capitalization, sharing positive personal information in a relationship, has gained considerable attention for benefitting the discloser of positive information. However, this study is the first to examine the effects of capitalization on the listener who celebrates the news, the celebrator. Thirty-nine college students participated in a daily diary capitalization intervention for 4 weeks in which every other week they celebrated capitalization. In diaries, participants reported experiencing more positive emotions when celebrating than when not celebrating. The discloser’s positive reaction to the celebration mediated the relationship between the number of celebrations and the celebrator’s higher positive emotions. In addition, more celebrations per day and feeling more authentic during celebrations predicted higher positive emotions. However, the perceived closeness of the relationship between the discloser and the celebrator was not associated with the effect of celebrating. Implications for the use of capitalization in different contexts and relationships are discussed.
The Use of an Auxiliary Matrix to Count Trees in Bipartite and Complete Graphs
Authors: Fielder D. C. , Hoggatt V. E.
Published: May 2015

Use is made of an auxiliary matrix to count trees of complete bipartite graphs. One form of the auxiliary matrix achieves partial diagonalization of the node admittance matrix and a second form of the same matrix completes the enumeration. Extension of the results is shown to be compatible with a known count for trees of complete graphs.
Electronic Circuit Analysis Using Apl
Authors: Mitchell R. H. , Penstone S. R.
Published: May 2015

This paper describes the use of a time-shared APL interactive facility in the teaching of electronic circuit analysis and design

A set of APL functions are described which allow students to use a step-by-step procedure to solve network problems. These functions calculate the admittance matrix, determinants, cofactors, transfer impedances and gains. An a.c. response program which uses the above functions to calculate the overall frequency response is also presented.
Examinations and Continuous Assessment
Authors: Bailey A. G. , Beynon J. D. E. , Sims G. D.
Published: May 2015

No course may be properly assessed before several, almost self-evident, basic questions about course objectives have been answered. Several types of continuous assessment are considered in the light of practical experience which show that continuous assessment techniques tend to produce a more uniform performance throughout a class, with fewer failures but also fewer students with very high marks. Continuous assessment techniques seem to be particularly appropriate for certain first year undergraduate courses.
The Influence of High Source Impedance on Controlled Bridge Rectifiers
Authors: Smith I. R. , Williams S.
Published: May 2015

An analysis is presented of inductively-loaded single-phase and three-phase thyristor bridge rectifier circuits, in which the source impedance cannot be neglected. It is shown that, as the ratio of the source reactance to the load resistance is raised, modes of operation with differing characteristics occur. Although the effect of an increased delay in the thyristor firing signals is normally to reduce the output voltage, it is shown that under certain conditions no change whatsoever is produced in the circuit wave-forms.
Analogue Computer Simulation of Delta-Modulators
Authors: McIntosh F. G. , Topping J. D.
Published: May 2015

Normal and adaptive delta-modulation is simulated allowing display, examination and investigation of quantization noise, slope overload and threshold of coding. Suggestions for the construction of a special purpose unit are also given. The simulation formed part of the investigation and subsequent design of an adaptive delta-modulation delay system.
Faraday's Law and Newton's Law of Motion
Authors: Freeston I. L.
Published: May 2015

By considering the motion of electrons in a plasma-filled capacitor, the mass of the electrons is shown to give rise to an apparent inductance.
An Unnecessary Controversy
Authors: Scroggie M. G.
Published: May 2015

There is ample evidence of misunderstandings and confusion over conventions relating to even such a simple circuit as a generator feeding a load. The reasons for this are traced and a simple solution offered which harmonizes opposing arguments and renders controversy unnecessary.
An Approach to Optimal Control for Engineering Undergraduates — Part 1
Authors: Owens D. H.
Published: May 2015

The paper illustrates an approach to the teaching of optimal control in the presence of hard constraints at an undergraduate level. The treatment is rigorous but simple and includes concepts essential for postgraduate studies and the introduction of numerical optimization methods.
Applications of the Transit-Time Current — Voltage Relationships to Negative — Conductance Devices
Authors: Lam Y. W.
Published: May 2015

The current-voltage relationships developed in the previous paper is applied to two examples: the transistor transit-time oscillator and the Read avalanche diode. It is shown that transit time in the semiconductor alone is insufficient to create negative conductance which is essential for oscillation to take place. Instead additional phase shift must be introduced. In both examples treated in this paper, the additional phase shift comes from the carrier-injection mechanism.
Some Comments on Thomson's Theorem
Authors: Mahedero B. , Rodríguez-Izquierdo G. , Civit A.
Published: May 2015

In this work some proofs of Thomson's theorem are discussed. Attention is focused on some points which seem to be disregarded by some authors. In this way a more thorough comprehension of the physical situation involved is gained.
A Note regarding the Condition of Oscillation for a Y Oscillator in Terms of the Cascading Parameters
Authors: Rahneberg E. W.
Published: May 2015

The condition for oscillation for a Y-type oscillator whose topology is suitable for microstrip circuits is derived in terms of the cascading parameters. This derivation may be used as an instructive example demonstrating the application of the cascading parameters.
Use of Mini-Computers for Fault Studies
Authors: Oghanna W.
Published: May 2015

For fault studies users of commercial programs lose a feeling for the system under study because of remoteness and lack of understanding of the working program. To overcome this deficiency a program is written in BASIC for a PDP8/e mini-computer. The main feature of this program is the form of questions and answers so that users waste no time in preparing required forms or reading instructions. Furthermore users continuously follow the progress of the program calculations.
A Note on the Laplace Transform
Authors: Brady T. W.
Published: May 2015

A new method of obtaining inverse transforms is suggested, which shows some advantages over partial fraction expansion methods. It uses linear combinations of the complex variable ‘ s’ as differential or integral operators; it also uses properties which a transform and its derivatives possess at the origin of time. The convolution integral is used for some difficult inversions.
Methods for the Summation of Infinite Series in Closed Form
Authors: Al-Hakkak Mohammed
Published: May 2015

The paper discusses four analytical methods for the summation of infinite series in closed form. Many illustrative examples are given including some with direct relevance to electrical engineering subjects like Fourier analysis of circuits, potential solutions of Laplace's equation, and finite differences.
A Multi-Function Transducer for Use in a Machines Laboratory
Authors: Kulkarni D. V. , Bowhay B. K.
Published: May 2015

The need frequently arises in a machines laboratory for an instrument which provides analog outputs corresponding to quantities such as speed, current, load angle and power normally measured by conventional means. The article describes the principle of operation and some applications of an instrument designed to provide such outputs. These outputs have been used to drive X-Y recorders and in control systems in both the steady and the dynamic state.
A Survey of Industrial Attitudes to Undergraduate Electrical Engineering Courses
Authors: Halder A. K. , Jordan T. A. , Carter G.
Published: May 2015

A questionnaire survey of the opinions of major employers of Electrical Engineering graduates concerning the relevance to their needs of undergraduate courses in this discipline, in the University of Salford, has been conducted. The generally poor response does not allow detailed comparisons to be made, but a few of the more important consensus views concerning the style of courses and the qualities of graduates are summarized.
A Demonstration Fourier Synthesizer
Authors: Taylor P. L. , Fitzpatrick M.
Published: May 2015

The instrument comprises a fundamental RC oscillator at a frequency of 256 Hz, and harmonic oscillators up to the twelfth all phase-locked to the fundamental. The output of each oscillator is variable in amplitude, and in phase through 360° using an unusual resistive phase-shifter.
An Iterative Parameter Approach to the Analysis of Unsymmetrical Multiconductor Systems
Authors: Indulkar C. S. , Thiruvengadam S.
Published: May 2015

A method of computing the matrix iterative admittances and matrix propagation functions for a multiconductor unsymmetrical system is presented. The admittance parameters of the unsymmetrical system are then derived in terms of its iterative parameters. Finally, the method of obtaining the admittance parameters of an n-section recurrent cascade is described.
Teaching Electronics Using Self-Paced Instruction
Authors: Dorey A. P. , Wilkins B. R.
Published: May 2015

An introductory course in Electronic Circuits and Systems has been established for first year Electronics students using a form of self-paced instruction. After describing the organisation of the course, the paper discusses the first year of operation, with reference to student reactions and examination performance.
A New Approach to Examinations
Authors: Hardie N. S.
Published: May 2015

The view is expressed that engineering examinations would satisfy many of their critics if they were designed to assess directly the skills which an engineer needs in his work.
Manpower for Engineering Laboratory Courses
Authors: Aharoni Herzl , Cohen Arnon
Published: May 2015

Two major problems of student laboratory courses are analyzed and discussed: (1) the qualifications and motivations of typical laboratory instructors, and (2) the attitude at the departmental policy-making level towards the laboratory. The paper concentrates mainly on the presentation of problems, but also suggests some short-term solutions.
A Simple and Formal Demonstration of the Degrading Effect of Intersymbol Interference in Data Transmission
Authors: Boutin N. , Morissette S. , Campagna M.
Published: May 2015

Experimentally, it is well known that intersymbol interference always degrades performances of data transmission. A simple formal mathematical proof of that statement is derived in this paper.
Simple Experiments in Digital Video Transmission
Authors: Leung C. K. , Wade J. G.
Published: May 2015

Aspects of digital video transmission systems are incorporated into a low-cost equipment for engineering training purposes. The equipment described simulates a p.c.m. monochrome video link and incorporates scrambling, automatic word framing and error concealment, Word framing and the problem of error extension are discussed in some detail.
An Effective Demonstration of the Armature Reaction in a Synchronous Machine
Authors: Ma W. F.
Published: May 2015

Two-axis excitation is employed advantageously with a modified slip-ring induction machine to demonstrate vividly the armature m.m.f. of an alternator so that the physical concepts or visualization of its armature reaction and synchronous reactance are improved.
Sparse Matrices and Linear Graph Theory
Authors: Mullineux N. , Reed J. R.
Published: May 2015

Motivation for the choice of order of elimination in dealing with sparse symmetric matrices is provided by consideration of a network analogue and then generalized to asymmetric matrices.
An Economical Implementation of an Ultrasonic Pulse Compression System for Non-Destructive Testing
Authors: Lam F. K.
Published: May 2015

A linear F.M. ultrasonic pulse compression system suitable for flaw detection has been economically implemented by using an ultrasonic delay line. The operating system has a time bandwidth product of 84 and sidelobe levels below — 25 dB. Results relating to the system detection and resolution capabilities are presented.
Analysis of Highly-Saturated Synchronous Motor with Cylindrical Excited Rotor
Authors: Chalmers B. J. , Önbilgin G.
Published: May 2015

The paper presents an analysis of torque production in a synchronous motor with constant-current supply under highly-saturated conditions, using the Frohlich approximation to represent the magnetisation characteristic. Attention is focussed upon conditions for optimum torque production. It is shown that the torque angle at maximum torque can significantly exceed 90°. Computations are compared with test results.
On the Organization and Operation of a Senior Project Laboratory
Authors: Cohen Arnon
Published: May 2015

A four-year experience with the organization and operation of an undergraduate project laboratory is discussed. The ‘project’ nature of work is emphasized by requiring a detailed proposal, written and oral reports and by strict regulation of team work, budget and time-table. Analysis of cost and manpower problems are given.
Forward Error Correction by Means of Microprocessors
Authors: Green D. H. , Ambler A. P.
Published: May 2015

The feasibility of employing a microprocessor to perform the various tasks involved with the implementation of a number of well known error-control coding schemes is investigated. It is demonstrated that reasonable data-rates can be achieved with even quite powerful codes.
Electrical Engineering Aspects of Science Degree Studies at the University of the South Pacific
Authors: Ward J. F.
Published: May 2015

The University of the South Pacific, now a decade old, serves about eleven sovereign countries of the South Pacific Region. Its science courses introduce electrical topics and principles of communications normally met with in electrical engineering courses. Material science and energy considerations round off this knowledge in the context of the needs of the region.
Longer Courses for Australian Engineers in the Future?
Authors: Gerofi J. P.
Published: May 2015

After describing the awards given by Electrical Engineering schools in Australia, the author discusses course planning for the next decade, considering technological developments and social and employment pressures. He proposes a five year, two award structure for future professional engineering courses, and bridging courses for prospective students with inadequate background in Mathematics and Physics.
Graphical Determination of Load Characteristic of Isolated Salient-Pole Alternator
Authors: Rajaraman K. C.
Published: May 2015

Existing graphical methods of Walker and Knight and Haddock require the plotting of a limacon and give only one point on the load caharacteristic. A simple adaptation of these is suggested which yields an easy and rapid method of deriving the entire load characteristic from open circuit to short circuit.
First Year Practical Project in Electric Motor Design at the University of Nottingham
Authors: Paull C. J. , Bradley K. J.
Published: May 2015

The paper presents a simple approach to the design of a small reluctance motor considered suitable for students of limited engineering experience. A theoretical analysis is followed by a discussion of the relevant practical considerations.
An Approach to Teaching the Design of Electromechanical Devices
Authors: Williamson S. , Penman J.
Published: May 2015

The article is concerned with a method for teaching the design of electromechanical devices to undergraduates. The method is based on the concept of realism, using manufacturer's catalogues and ‘experience’ information wherever possible. The design of an electromagnet is described in detail as an illustration of the method.
Analysis of Current-Fed Induction Machine Including Saturation of Magnetisation Characteristic
Authors: Chalmers B. J. , Bouchiker S.
Published: May 2015

A new analysis of induction machines with constant-current excitation is presented, using a modified Fröhlich approximation to the magnetisation characteristic. The normalised solution for conditions at maximum torque is given in the form of general curves for a range of values of rotor leakage reactance.
Synthesis of Active RC All-Pass Networks
Authors: Ho C. F.
Published: May 2015

A simple method for the synthesis of a second order active RC all-pass network is discussed. It is essentially a coefficient matching technique. The synthesis gives a minimum number of capacitors network and the pole frequency is controlled by resistors only.
An Approach to the Design of Filter Inductors for DC Power Supplies
Authors: Szuba Stefan , Konopinski Tadeusz
Published: May 2015

This paper describes the design method which minimises the d.c. winding resistance of an inductor for power supply. The method uses the normal magnetisation curve and the family of relative incremental permeability curves of magnetic material. The results of calculations and practical design are given and commented on.
Conservation Laws in Circuit Theory
Authors: Logan J. David
Published: May 2015

This article presents a method for determining first integrals for nonlinear second-order differential equations arising in electrical engineering problems. It is based on finding a set of transformations under which the variational problem associated with the given differential equation is invariant. An example involving a simple R-C-L circuit is presented.
Eigenvalue Analysis of Identical Ladder Networks
Authors: Indulkar C. S.
Published: May 2015

Identical ladder networks with open-circuit, short-circuit, and matched terminations have been analysed using the eigenvalue technique. The technique has been applied to determine the steady-state and transient potential distributions across a string of 400 KV insulators. The latter has been calculated by using this technique and the Fourier transform method.
A Degree-Enhancement Scheme in Electronic Engineering
Authors: Sewell J. I.
Published: May 2015

A scheme is outlined which has a five year structure, with a fully integrated academic and industrial training programme. The academic content is discussed in detail and includes main core subjects, laboratory and project work, computer education, industrial lecturers' input and business elements of the course.