bluuebunny/crossref_metadata_2025 huggingface dataset:
Interobserver variability of ventilatory anaerobic threshold in asymptomatic volunteers
Authors: Kaczmarek Sabine , Habedank Dirk , Obst Anne , Dörr Marcus , Völzke Henry , Gläser Sven , Ewert Ralf
Published: January 2020

Background: The ventilatory anaerobic threshold (VO2@AT) has been used in preoperative risk assessment and rehabilitation for many years. Our aim was to determine the interobserver variability of AT using cardiopulmonary exercise (CPET) data from a large epidemiological study (SHIP, Study of Health in Pomerania). Methods: VO2@AT was determined from CPET of 1,079 cross-sectional volunteers, according to American Heart Association guidelines. VO2@AT determinations were compared between two experienced physicians, between physicians and qualified medical assistants, and between physicians or medical assistants and software-based algorithms. For the first 522 data sets, the two physicians discussed discrepant readings to reach consensus; the remaining data sets were analyzed without consensus discussion. Results: VO2@AT was detectable in 1,056 data sets. The physicians recorded identical VO2@AT values in 319 out of 522 cases before consensus discussion (61.1%; intraclass correlation coefficient [ICC]: 0.90; 95% confidence interval [CI]: 0.88–0.92) and in 700 out of 1,056 cases overall (66.3%; ICC: 0.95; 95% CI: 0.95–0.96), with an interobserver difference of 0 ± 8% (95% limits of agreement [LOA]: ±161 mL/min). The interobserver difference was − 2 ± 18% (95% LOA: ±418 mL/min) between a physician and medical assistants, and − 19 ± 24% to − 22 ± 26% (95% LOAs: ±719–806 mL/min) between physicians or medical assistants and software-based algorithms. Conclusions: Experienced physicians show high agreement when determining AT in asymptomatic volunteers. However, agreement between physicians and qualified medical assistants is lower, and there is substantial deviation in AT determination between physicians or medical assistants and software-based algorithms. This must be considered when using AT as a decision tool.
Long term management of obstructive sleep apnea and its comorbidities
Authors: Marin-Oto Marta , Vicente Eugenio E. , Marin Jose M.
Published: January 2020

Obstructive sleep apnea (OSA) is a worldwide highly prevalent disease associated with systemic consequences, including excessive sleepiness, impairment of neurocognitive function and daytime performance, including driving ability. The long-term sequelae of OSA include and increase risk for cardiovascular, cerebrovascular and metabolic syndrome disorders that ultimately lead to premature death if untreated. To ensure optimal long-term outcomes, the assessment and management of OSA should be personalized with the involvement of the appropriate specialist. Most studies have demonstrated inmediate improvement in daytime somnolence and quality of life with CPAP and other therapies, but the effect of long-term treatment on mortality is still under debate. Currently, the long-term management of OSA should be based on a) identifying physiological or structural abnormalities that are treatable at the time of patient evaluation and b) comprehensive lifestyle interventions, especially weight-loss interventions, which are associated with improvements in OSA severity, cardiometabolic comorbidities, and quality of life. In long-term management, attention should be paid to the clinical changes related to a potential reoccurrence of OSA symptoms and it is also necessary to monitor throughout the follow up how the main associated comorbidities evolve.
Efficacy and safety profile of doxofylline compared to theophylline in asthma: a meta-analysis
Authors: Rogliani Paola , Calzetta Luigino , Ora Josuel , Cazzola Mario , Matera Maria Gabriella
Published: January 2020

Background: Oral methylxanthines are effective drugs for the treatment of chronic obstructive respiratory disorders. The novel methylxanthine doxofylline, that has bronchodilator and anti-inflammatory activities, is not affected by the major drawback of theophylline. Nowadays large-scale quantitative synthesis comparing the efficacy and safety profile of doxofylline vs. theophylline in the treatment of asthma is still lacking. Therefore, we performed a quantitative synthesis to compare the efficacy/safety profile of doxofylline and theophylline in asthma. Methods: A pairwise and network meta-analyses were performed to assess the impact of doxofylline vs. theophylline and placebo on the change in asthma events, risk of adverse events (AEs), forced expiratory volume in 1 s (FEV1), and salbutamol use. Results: Data obtained from 696 asthmatic patients were extracted from 4 randomized controlled trials published between 2015 and 2018. Doxofylline was significantly (P < 0.05) more effective than theophylline in reducing the daily asthma events (mean difference − 0.14, 95%CI -0.27 – 0.00) and risk of AEs (relative risk 0.76, 95%CI 0.59–0.99). Doxofylline was as effective as theophylline in improving FEV1, and a trend of superiority (P = 0.058) was detected for doxofylline over theophylline with respect to the reduction in the use of salbutamol as rescue medication. The rank of effectiveness was doxofylline>theophylline> > placebo, and the rank of safety was placebo>doxofylline> > theophylline. Conclusions: Doxofylline is an effective and safe methylxanthine for the treatment of asthma, with an efficacy/ safety profile greater than that of theophylline. Trial registration: Meta-analysis registration: CRD42019119849.
Comparison of different conditions for DNA extraction in sputum - a pilot study
Authors: Oriano Martina , Terranova Leonardo , Teri Antonio , Sottotetti Samantha , Ruggiero Luca , Tafuro Camilla , Marchisio Paola , Gramegna Andrea , Amati Francesco , Nava Fabrizio , Franceschi Elisa , Cariani Lisa , Blasi Francesco , Aliberti Stefano
Published: January 2020

Background: The analysis of microbiome in respiratory samples is a topic of great interest in chronic respiratory diseases. The method used to prepare sputum samples for microbiome analysis is very heterogeneous. The selection of the most suitable methodology for DNA extraction is fundamental to have the most representative data. The objective of this study was to compare different conditions for DNA extraction from sputum in adult patients with bronchiectasis. Methods: Five sputum samples from bronchiectasis patients were collected at the Policlinico Hospital in Milan, Italy. Eighteen conditions for DNA extraction were compared, including two enzyme-based (Roche and Zymo) and one beads-based (Mobio) technique. These techniques were tested with/without Dithiothreitol (DTT) and with/without lysostaphin (0.18 and 0.36 mg/mL) step. DNA was quantified, tested using Real-time PCR for 16S rDNA and S. aureus and, then, microbiome was evaluated. Results: Although 16S rDNA was similarly detected across all the different techniques, Roche kit gave the highest DNA yield. The lowest Ct values for Real-time PCR for S. aureus was identified when lysostaphin was added. Considering genera from microbiome, alpha diversity indices did not show any significant differences between techniques, while relative abundances were more similar in presence of DTT. Conclusions: None of the conditions emerged to be superior to the others even if enzyme-based kits seem to be needed in order to have a higher extraction yield.
Indoor bacterial load and its correlation to physical indoor air quality parameters in public primary schools
Authors: Andualem Zewudu , Gizaw Zemichael , Bogale Laekemariam , Dagne Henok
Published: January 2020

Background: Poor indoor air quality is a great problem in schools due to a high number of students per classroom, insufficient outside air supply, poor construction and maintenance of school buildings. Bacteria in the indoor air environment pose a serious health problem. Determination of bacterial load in the indoor environment is necessary to estimate the health hazard and to create standards for indoor air quality control. This is especially important in such densely populated facilities like schools. Methods: Institutional based cross-sectional study was conducted among 51 randomly selected classrooms of eight public primary schools from March 29–April 26, 2018. To determine the bacterial load passive air sampling settle plate method was used by exposing a Petri dish of blood agar media for an hour. The Pearson correlation matrix was employed to assess the correlation between bacterial load and physical parameters. Results: The grand total mean bacterial load was 2826.35 CFU/m3 in the morning and 4514.63 CFU/m3 in the afternoon. The lowest and highest mean bacterial load was recorded at school 3 (450.67 CFU/m3) and school 5 (7740.57 CFU/m3) in the morning and afternoon, respectively. In the morning relative humidity (r = −0.7034), PM2.5 (r = 0.5723) and PM10 (r = 0.6856); in the afternoon temperature (r = 0.3838), relative humidity (r = − 0.4014) were correlated with indoor bacterial load. Staphylococcus aureus, Coagulase-negative Staphylococcus species and Bacillus species were among isolated bacteria. Conclusions: High bacterial load was found in public primary schools in the Gondar city as compared to different indoor air biological standards. Temperature, relative humidity and particulate matter concentration (PM2.5 and PM10) were associated with the indoor bacterial load. Staphylococcus aureus, Coagulase-negative Staphylococcus species and Bacillus species were among isolated bacterial species. Attention should be given to control those physical factors which favour the growth and multiplication of bacteria in the indoor environment of classrooms to safeguard the health of students and teachers in school.
Immunostimulants in respiratory diseases: focus on Pidotimod
Authors: Puggioni Francesca , Alves-Correia Magna , Mohamed Manar-Farouk , Stomeo Niccolò , Mager Riccardo , Marinoni Massimiliano , Racca Francesca , Paoletti Giovanni , Varricchi Gilda , Giorgis Veronica , Melioli Giovanni , Canonica Giorgio Walter , Heffler Enrico
Published: January 2020

Usefulness of Pidotimod and its role as immunostimulant, has been discussed, we know, for several decades. Nevertheless, there is still much to know. Understanding its mechanisms and its potential usefulness in airway infections and its prevention, asthma both Th2 and non Th2 type, bronchiectasis, as adjuvant in vaccination and in allergen immunotherapy still remains to clearly unveil. The aim of this paper was to provide a useful updated review of the role of the main available immunostimulants, giving particular focus on Pidotimod use and its potentials utility in respiratory diseases. Pidotimod showed its usefulness in reducing need for antibiotics in airway infections, increasing the level of immunoglobulins (IgA, IgM, IgG) and T-lymphocyte subsets (CD3+, CD4+) endowed with immunomodulatory activity that affect both innate and adaptive immune responses. Higher expression of TLR2 and of HLA-DR molecules, induction of dendritic cell maturation and release of pro-inflammatory molecules, stimulation of T lymphocyte proliferation and differentiation toward a Th1 phenotype, as well as an increase of the phagocytosis have been demonstrated to be associated with Pidotimod in in vitro studies. All these activities are potentially useful for several respiratory conditions such as asthma, COPD, and recurrent respiratory tract infections.
Correction to: Patients’ usability of seven most used dry-powder inhalers in COPD
Authors: Dal Negro Roberto W. , Turco Paola , Povero Massimiliano
Published: January 2020

Correction to: Multidiscip RespirMed (2019) 14:30 https://doi.org/10.1186/s40248-019-0192-5After publication of the Original research article [1] it was brought to our attention that the sentence at the bottom of the section entitled Discussion (pag 6 of 9, just below Fig. 4) must be corrected as follows: “In real life, DPIs are highly prescribed in Italian COPD patients being their prescription usually independent of their known basic characteristics and technical differences, such as the different number of main actions required for their actuation (7 for Breezhaler, 4 for Turbohaler, and 3 for the remaining devices),” and their intrinsic resistance, ranging from 0.017 kPa0.5 L/min to 0.039 kPa0 .5 L/min [28, 29].
Absenteeism, labour turnover and management style
Authors: Human P. G.
Published: January 2020

Labour turnover and absenteeism rates are relatively easily measurable forms of behaviour. This article investigates the validity of these rates as indicators of organizational effectiveness. It is argued that management style and motivational strategies are related to absenteeism and labour turnover. Absenteeism and labour turnover are viewed as examples of deviant industrial behaviour and consequently as reflections of employee dissatisfaction with management. The implications of the incidence of and variations in these two phenomena are discussed together with their relevance to successful management, and their practical applicability as tools to aid the employer.Arbeidsomset- en werksafwesigheidsyfers is redelik maklik meetbare verskynsels en word jaarliks in meeste bedryfsorganisasies bepaal. Hierdie artikel ondersoek die geldigheid van hierdie syfers as indikatore van organisasie-effektiwiteit. Die argument is dat bestuurstyl en motiveringstrategie aan die een kant, verband hou met werksafwesigheid en arbeidsomset aan die ander kant. Werksafwesigheid en arbeidsomset word beskryf as voorbeelde van afwykende industriele gedrag en daarom as wyses waarop werknemers hul ontevredenheid ten opsigte van die werkgewers uitdruk. Die implikasies van die voorkoms en variasies van hierdie twee verskynsels word bespreek, asook hulle praktiese toepasbaarheid as hulpmiddels vir die werkgewer, en hulle verband met suksesvolle bestuur.
Training for performance appraisal
Authors: Hofmeyr Karl B.
Published: January 2020

The article discusses some of the typical problems associated with the successful implementation of performance appraisal. The problem of inadequate training of managers in how to deal with the face-to-face aspect of performance appraisal is highlighted. A relatively new approach to training in interpersonal skills, namely behaviour modelling, is described. This applied learning approach is aimed initially at changing behaviour rather than attitudes, with the intention that attitudes will later change to fall in line with the new behaviour. A particular performance appraisal system is briefly described and it is then shown how the four phases of behaviour modelling, i.e. key behaviours, modelling, role-playing and transfer of training, may be used to train managers how to appraise performance.Die artikel bespreek sommige van die tipiese probleme wat met die geslaagde implementering van prestasiewaardasie ondervind word. Die probleem van onvoldoende opleiding van bestuurders in die hantering van die mens-tot-mens aspek van prestasie-waardasie word beklemtoon. 'n Relatief nuwe benadering tot opleiding in interpersoonlike vaardighede, te wete gedragsmodellering, word beskryf. Hierdie toegepaste leerbenadering is daarop gemik om aanvanklik gedrag eerder as houdings te verander, met die doel dat houdings later sal verander om by die nuwe gedrag aan te pas. 'n Besondere stelsel van prestasie-waardasie word kortllks beskryf, en dit word dan aangetoon hoe die vier fases van gedragsmodellering: sleuteloptredes of -stappe, modellering, rol-spel en oordrag van opleiding, gebruik kan word om bestuurders op te lei in die praktyk van prestasie-waardasie.
A model of managerial power in the organization
Authors: Templer Andrew J.
Published: January 2020

In this first article in a series of three on power, the concept of managerial power is introduced and a model developed of its operation in the organization. The nature of managerial power is investigated and its importance as a medium of organizational analysis is emphasized. Attention is given to the theoretical requirements of an adequate model of managerial power and the proposed model is evaluated in terms of these criteria requirements. It is shown that an adequate model must cover both macro and micro-levels of analysis. In this article, the focus is on the macro-level application of the power model.Hierdie eerste van 'n reeks van drie artikels oor mag, gee 'n inleiding tot die konsep van bestuursmag, en beskryf 'n model van die werking van bestuursmag in die organisasie. Die aard van bestuursmag word ondersoek en die belangrikheid daarvan as hulpmiddel tot organisasie-ontleding word beklemtoon. Aandag word gegee aan die teoretiese vereistes van 'n bruikbare model van bestuursmag, en die voorgestelde model word volgens hierdie kriteria ge-evalueer. Dit word aangetoon dat 'n bruikbare model sowel makro- as mikrovlakke van ontleding moet dek. In hierdie artikel is die klem op die makrovlaktoepassing van die mags model.
Marketing case study: How to beat the litterbug
Authors: Clarke Hugh G.
Published: January 2020

No abstract available.
Working women and organizations: Are they compatible?
Authors: Kellerman Rita
Published: January 2020

Problems regarding the more permanent integration of women into organizations are considered. Organizations must regard female employees as a profitable investment before they will be prepared to spend time and money on their training and development. On the other hand, it is women's responsibility to convince organizations that a woman can be as committed to a career as a man. Only then can they expect organizations to give them equal recognition and equal treatment. Factors influencing women's attitudes towards work and career achievement are discussed, followed by an analysis of the characteristics and family relationships of career women. Proposals are made on how women and employers can overcome problems regarding the full utilization of women.Probleme ten opsigte van die meer permanente integrasie van vroue in organisasies word oorweeg. Organisasies moet vroulike werknemers as 'n winsgewende belegging beskou alvorens tyd en geld aan hulle opleiding en ontwikkeling bestee sal word. Vroue, aan die ander kant, het die verantwoordelikheid om organisasies te oortuig dat die vrou net so loopbaanverbonde as die man kan wees. Eers dan kan hulle van organisasies verwag om hulle gelyke erkenning en gelyke behandeling te gee. Faktore wat vroue se houdings teenoor werk en loopbane beinvloed word bespreek, gevolg deur 'n ontleding van die eienskappe en gesins-verhoudings van loopbaan-vroue. Voorstelle word gemaak oor hoe vroue en werkgewers probleme met betrekking tot die volle benutting van vroue kan oorkom.
Uncertainty-reducing techniques in technological innovation
Authors: Sparrius A. J.A.
Published: January 2020

Technology-intensive innovation is fraught with all sorts of uncertainties - uncertainties which can neither be averted nor ignored but have to be managed. This paper discusses techniques on how to handle such uncertainties in high-technology development projects under conditions of severe time pressure. The key lies in postponing decision-making if uncertainty is intolerably high, and structuring the development project in such a manner that progress is not delayed, while taking steps to rapidly and systematically reduce the uncertainty. These techniques turn out to be simple but profound.Tegnologie-intensiewe innovasie word gekenmerk deur allerlei soorte onsekerhede - onsekerhede wat nog vermy nog verontagsaam kan word. Hierdie artikel bespreek tegnieke vir die hantering van sulke onsekerhede in hoe-tegnologie ontwikkelingsprojekte onder ernstige tydsdruk. Die sleutel le in die uitstel van besluitneming indien die onsekerhede ontoelaatbaar groot is, en in die strukturering van die ontwikkelingsprojek in so 'n wyse dat vordering nie belemmer word nie, terwyl stappe geneem word om die onsekerhede vinnig maar stelselmatig uit die weg te ruim. Hierdie tegnieke blyk eenvoudig dog diepgaande te wees.
Leadership for the 80's
Authors: Schutte Grant
Published: January 2020

From a speech at the MBI graduation dinner, Johannesburg, 9 May 1980.
The rise and fall of network techniques in project management
Authors: Ghyoot V.
Published: January 2020

No abstract available.
Theory and practice in management education: A perspective for Business Schools
Authors: Orpen Christopher
Published: January 2020

It is argued that the effective teaching of management requires both students and teachers to be involved in collaborative research of one kind or another. This, in turn, requires an integration of theory and practice in which students and teachers jointly; apply research-based generalizations to a variety of situations based on their diagnoses of those situations; modify these generalizations on the basis of their success or failure in application, and apply the modified generalizations to still further situations - a circular process that lies at the heart of any research effort. A number of practical suggestions are made for the attainment of this kind of integration between teaching (theory) and learning (practice). The integrative model proposed in this paper is contrasted with the traditional model, in terms of which research conducted by independent researchers stands apart from teaching and the practical application of knowledge.Dit word aangevoer dat effektiewe onderrig van die bestuurskuns van beide studente en dosente vereis dat hulle in samewerking by een of ander navorsingsprojek betrokke sal wees. Dit vereis weer 'n integrasie van teorie en praktyk waarin studente en dosente gesamentlik, navorsingsgebaseerde veralgemenings op verskillende situasies, na gelang van hulle diagnose van daardie situasies, toepas; hierdie veralgemenings op die basis van hulle sukses of mislukkings in die toepassing daarvan wysig, en die wysigings in verdere situasies toepas - 'n kringloopproses wat betrekking het op enige navorsingspoging. 'n Aantal praktiese voorstelle vir die bereiking van hierdie soort integrasie tussen onderrig (teorie) en leer (praktiese toepassing) word aan die hand gegee. Die geintegreerde model wat in hierdie artikel voorgestel word is in kontras met die tradisionele model, in terme waarvan navorsing deur onafhanklike navorsers geskei is van die onderrig en die praktiese toepassing van kennis.
The institution of consumer instalment sales credit and its relationship to cyclical fluctuations
Authors: Meyer W. N.
Published: January 2020

The contribution of consumer instalment sales credit (hire purchase credit) to fluctuations in economic activity is the source of some conflict between two diverse viewpoints. On the one side there are those who use a Keynesian analysis to argue that an increasing volume of consumer instalment sales credit has an accelerating effect on the expansion of effective demand far out of proportion to its own relative size and that a subsequent retardation in consumer instalment extensions will cause a more rapid acceleration in the contraction phase of the cycle. The results, respectively, would be a higher peak to a boom and a deeper recession. On the other hand, some writers, while not refuting the Keynesian analysis, feel that, although consumer hire purchase credit's influence on cyclical fluctuations merits careful study, its possible destabilizing effect is not so significant as to overshadow all its desirable aspects. They argue that the cyclical behaviour is questionable and cannot be isolated from other elements of the economy. This article will analyse and evaluate some of the existing theories to discover their weaknesses and strong points.Die bydrae van verbruikershuurkoopkrediet tot fluktuasies in ekonomiese aktiwiteit is die bron van konflik tussen twee uiteenlopende gesigspunte. Aan die eenkant is daar die wat deur die toepassing van 'n Keynesiaanse analise argumenteer dat 'n toenemende volume van verbruikershuurkoopkrediet 'n versnellende effek op die uitbreiding van effektiewe aanvraag het buite verhouding tot sy eie relatiewe grootte, en dat 'n daaropvolgende afname in verbruikershuurkoopkrediet 'n vinniger versnelling in die kontraksiefase van die siklus sal veroorsaak. Die gevolge is, onderskeidelik, 'n hoer piek in die oplewing en 'n daaropvolgende diaper depressie. Aan die ander kant is sommige skrywers, terwyl hulle nie die Keynesiaanse analise verwerp nie, van mening dat, hoewel verbruikershuurkoopkrediet se invloed op sikliese fluktuasies deeglike studie regverdig, die moontlike onbestendige effek daarvan nie so beduidend is dat dit al die gunstige aspekte daarvan oorskadu nie. Hulle argument is dat sikliese gedrag bevraagteken kan word en nie van ander elemente van die ekonomie geskei kan word nie. Hierdie artikel analiseer en evalueer sommige van die bestaande teoriee om hulle swakhede en goeie eienskappe uit te lig.
Mediumtermynvooruitskatting deur die ontleding en sintese van periodisiteit
Authors: Reinecke R.
Published: January 2020

The programme suit TEMPOS is an aid to medium-term forecasting of national major economic time series. It is based on the assumption that the well-known recurrent, but non-periodic business cycles can be represented by simple but strictly periodic cyclic movements, each driven by a separate but not necessarily known external economic factor. As the elements of such a model are individually extrapolatable, the model as a whole may be extrapolated over a limited horizon.Die suite rekenaarprogramme TEMPOS is 'n hulpmiddel vir vooruitskatting in die mediumtermyn van nasionale omvang ekonomiese tydreekse. As uitgangspunt geld die aanname dat die bekende herhalende maar nie-periodieke konjunktuurgolwe voorgestel kan word deur eenvoudiger maar streng periodieke golwe, elk gedrewe deur eiesoortige eksterne ekonomiese faktore.
Marketing control in retailing
Authors: Abratt Russell
Published: January 2020

Control has long been recognized as one of the tasks a manager must perform. The objective of this paper is to detail the steps involved for marketing control from a retail managers point of view. There is an abundance of literature that deals with control and especially marketing control. Yet there is very little specific information for retail managers to follow. This paper discusses why marketing control is necessary in the retail firm and then gives an in-depth view of the marketing control process. It also attempts to show how effective marketing control in retailing may help the retailer to survive in a rapidly changing environment in Southern Africa today.Dit is reeds geruime tyd aanvaar dat beheer een van die take van 'n bestuurder is. Die oogmerk van hierdie artikel is om die stappe wat betrokke is in bemarkingsbeheer vanuit die bestuur se oogpunt in besonderhede te bespreek. Daar bestaan baie literatuur waarin beheer, veral bemarkingsbeheer bespreek word, maar daar is baie min inligting beskikbaar wat veral op die kleinhandelbestuur betrekking het. Hier word 'n uiteensetting gegee waarom bemarkingsbeheer in die kleinhandelsonderneming nodig is, en die bemarkingsbeheerproses word in diepte beskou. Die artikel is verder ook 'n poging om aan te toon hoe doeltreffende bemarkingsbeheer in die kleinhandel sal help om die kleinsakeman kop bo water te laat hou in die snel veranderende omgewing van Suider-Afrika.
Recommendations of the first report of the inter-departmental committee of inquiry into certain specific pension matters
Authors: Swanepoel W. B.
Published: January 2020

No abstract available.
Die Johannesburgse Effektebeurs as rasionele kapitaalmark
Authors: Brummer Leon M. , Jacobs Pieter J.
Published: January 2020

The Johannesburg Stock Exchange as an efficient market. Finality has not yet been reached on the question whether the Johannesburg Stock Exchange complies with the requirements of the efficient market hypothesis. The results of the research that are published in this article is therefore an attempt to make a contribution to the debate regarding the Johannesburg Stock Exchange as an efficient market. By way of serial correlations as well as runs tests an investigation was carried out into the behaviour of the prices of 94 quoted shares for the period 1970 to 1977. The results of the study give rise to the conclusion that the Johannesburg Stock Exchange does not statistically comply with the weak form of the efficient market hypothesis (the random walk hypothesis), as a measure of dependence between successive price changes was found. Seen from an economic point of view it is, however, doubtful whether investors could use this small degree of dependence between price changes to gain higher returns on share investments.Uitsluitsel met betrekking tot die mate waartoe die Johannesburgse Effektebeurs aan die vereistes vir 'n rasionele mark voldoen, is nog nie verkry nie. Die resultate wat in hierdie artikel voorkom is daarom 'n poging om 'n bydrae in die debat rakende die Johannesburgse Effektebeurs as 'n rasionele mark, te maak. 'n Ondersoek na die markpryse van 94 genoteerde aandele vir die periode 1970-77 is deur middel van reekskorrelasiekoeffisiente en die lopietoets uitgevoer. Die resultate van die studie gee aanleiding tot die gevolgtrekking dat die Johannesburgse Effektebeurs nie statisties aan die swak vorm van die rasionele markhipotese (die willekeurige beweging van markpryse) voldoen nie, aangesien 'n mate van afhanklikheid tussen opeenvolgende prysveranderings gevind is. Uit 'n ekonomiese oogpunt gesien is dit egter twyfelagtig of beleggers hierdie afhanklikheid sal kan aanwend om hoer opbrengste op aandelebeleggings te bewerkstellig.
Setting Black advancement strategy
Authors: Badenhorst J. U.
Published: January 2020

Paper presented at Unisa SBL seminar 'Black advancement - The reality and challenge', in Pretoria, July 8, 1981.
Whither physiotherapy?
Authors: Editor The
Published: January 2020

No abstract available.
Temperature changes induced by continuous ultrasound
Authors: MacDonald B. L. , Shipster S. B.
Published: January 2020

An investigation was undertaken to measure temperature changes during therapeutic ultrasound. Various frequencies, intensities and times were used. As a result of their work the authors feel that more research should be carried out to determine the point at which high intensities of ultrasound produce dangerous temperature increases.
The high-dimensional cohomology of the moduli space of curves with level structures
Authors: Fullarton Neil J. , Putman Andrew
Published: January 2020

We prove that the moduli space of curves with level structures has an enormous amount of rational cohomology in its cohomological dimension. As an application, we prove that the coherent cohomological dimension of the moduli space of curves is at least

g – 2

. Well known conjectures of Looijenga would imply that this is sharp.
Dynamical aspects of the generalized Schrödinger problem via Otto calculus – A heuristic point of view
Authors: Gentil Ivan , Léonard Christian , Ripani Luigia
Published: January 2020

The defining equation

(\ast)\qquad \dot \omega_t=-F'(\omega_t)

of a gradient flow is
kinetic
in essence. This article explores some
dynamical
(rather than kinetic) features of gradient flows (i) by embedding equation

(\ast)

into the family of slowed down gradient flow equations:

\dot \omega^{\varepsilon}_t=- \varepsilon F'( \omega ^{ \varepsilon}_t)

, where

\varepsilon > 0

, and (ii) by considering the
accelerations

\ddot \omega ^{ \varepsilon}_t

. We shall focus on Wasserstein gradient flows. Our approach is mainly heuristic. It relies on Otto calculus.

A special formulation of the Schrödinger problem consists in minimizing some action on the Wasserstein space of probability measures on a Riemannian manifold subject to fixed initial and final data. We extend this action minimization problem by replacing the usual entropy, underlying the Schrödinger problem, with a general function on the Wasserstein space. The corresponding minimal cost approaches the squared Wasserstein distance when the fluctuation parameter

\varepsilon

tends to zero.

We show heuristically that the solutions satisfy some Newton equation, extending a recent result of Conforti. The connection with Wasserstein gradient flows is established and various inequalities, including evolutional variational inequalities and contraction inequalities under a curvature-dimension condition, are derived with a heuristic point of view. As a rigorous result we prove a new and general contraction inequality for the Schrödinger problem under a Ricci lower bound on a smooth and compact Riemannian manifold.
Heat Transfer Amplification through Special Tube Inserts and Metallic Nanofluids in Heat Exchanger
Authors: Karuppasamy M. , Saravanan R. , Chandrasekaran M. , Muthuraman V.
Published: January 2020

The heat transfer amplification is highly desired in aerospace and IC engine driven vehicles. Such amplification is achieved by active and passive methods. This research focuses the passive method of a specially designed tube insert. The objective of the study is to increase the heat transfer rate in the tube side of the heat exchanger with such special insert which creates the turbulence flow. Usually water is employed as heat transfer fluid. This investigation included the suspensions of metallic particles like alumina and copper oxides to the plain water with neglected pumping loss. The alumina based nanofluid outperforms and supported well for all the considered flow cases.
Investigation of Papaya Seed Methyl Ester Blended Diesel for Emission Reduction in Direct Injection Engines
Authors: Hemanandh J. , Ganesan S. , Shaik Fiaz A. , Gunasekar P.
Published: January 2020

The diesel engines are emitting toxic gases which affect the greenhouse gases. In this research, the methyl esters were extracted from waste papaya seed oil using transesterification process. The Direct Injection Kirloskar diesel engine at constant speed of 1500 rpm and compression ratio of 17.5:1 was used to test the fuel. The injection nozzle holes were varied from 3 to 4 holes. The emissions were recorded using AVL gas analyser. The 20% blend with 4-hole nozzle shows reduction in NOx, CO and CO2 emissions at full load. The performance is increased for 30% blend at full load.
Determination of Engine Misfire Location using Artificial Neural Networks
Authors: Ghazaly Nouby M. , Abdel-Fattah Muhammad , M. Makrahy Mostafa
Published: January 2020

Misfire in spark-ignition engines is one of the major faults that affect the power produced by the engine and pollute the environment and may cause further engine damage. This paper presents an evaluation of an artificial neural network based performance system through three most popular training algorithms namely Gradient Descent, Lavenberg-Marquadt and Quasi-Newton to determine the misfire location. Misfire is simulated by removing ignition coil to that cylinder namely Cylinder 1,2,3,4 and Cylinders 1 and 2, 1 and 4 and 2 and 3 with three different conditions such as idle, 2000 rpm and 3000 rpm. The results showed that the Quasi-Newton is higher in recognition rate average of 98.19 % but it takes more time to train. The Lavenberg-Marquardt algorithm is also good with an average recognition rate of 96.09 % with the fastest performance than Quasi-Newton. The gradient descent algorithm requires the network size to be more complicated to perform well with least time and high recognition rate.
Liquid Propulsion System Reliability Estimation using Computational Bayesian Approach with Multi-level Data
Authors: Muthukumar S. , Subhash Chandra Bose P. , Srivardhan R.A.
Published: January 2020

Liquid propulsion system (LPS) is a highly reliable and complex system that is used for the military and space applications. It consists of many flight critical components arranged in series configuration. Reliability is the most critical parameter for this system, even one subsystem failure leads to total failure of flight vehicle. Determining the achieved reliability of a LPS is a unique challenge for designer of these systems. The system reliability needs to be estimated with limited number of tests due to the destructive nature of tests, time and cost constraints. In this paper, reliability of LPS was estimated with subsystem test data using computational Bayesian approach. Component level, subsystem level and system level data are considered and a framework is created by combing all information. The reliability of the LPS was calculated using Markov Chain Monte Carlo (MCMC) simulation which has avoided numerical integration. Results are compared with Lindstorm Madden method and Bayesian hybrid method. Computational Bayesian approach can give reasonably better reliability estimate with limited test data.
Design, Analysis and Topology Optimization of a Connecting Rod for Single Cylinder 4â€“Stroke Petrol Engine
Authors: Pandiyan A. , Arunkumar G. , Premkumar G.
Published: January 2020

The aim of the study is to design, analyse and carry out a topology optimization of a connecting rod for single cylinder four stroke petrol engines. In order to obtain a 3D CAD model from existing physical connecting rod is developed through reverse engineering. A three dimensional CAD model of a connecting rod has been created using SOLIDWORKS and it is imported to ANSYS for the coupled steady-state thermal structural analysis, to verify the design of a connecting rod before and after weight reduction. For material optimization, three different aluminium alloy materials such as ADC12, LM6 and Al 6061â€“T6 alloy were used. From the results obtained from coupled steady-state thermal structural analysis and topology optimization, the optimized design of a connecting rod of Al 6061-T6 alloy shows the von-mises stress of 33.17 MPa, factor of safety 8.32 and total deformation 45.023 mm as compared to other two materials. Based on the topology optimization methodology, it is noted that Al 6061- T6 connecting rod material reduced the weight up to 7.98 % as compared with ADC12 without compromising the strength to weight ratio and ductility.
Semi-analytical Evaluation of Entropy Generation in 1-D Heat Conduction with Variable Thermal Conductivity
Authors: Anupkumar T. , Praveen Reddy A. , Sharma Noble , Narayan Rao N. , Srinivasa Rao B.
Published: January 2020

In the present study, steady state heat transfer in a slab is analysed by applying the principle of variation calculus to the entropy generation minimization. The governing equation of the phenomena is obtained by minimizing the total entropy generation over the slab by considering the irreversibility and variation of thermal conductivity as a function of spatial co-ordinates. The governing equation is solved to obtain the temperature distribution, internal heat generation due to irreversibility, entropy generation number and entropy transport into system. The apparent heat sources that come into existence because of the irreversibility in heat diffusion have made the minimization of entropy generation feasible.
Topology Optimization for Diffusive Heat Transfer in a Domain with Internal Heat Generation using Optimality Criteria
Authors: Anupkumar T. , Sharma Noble , Srinath A. , Satya Dileep G.
Published: January 2020

The standard volume to point heat conduction problem is used to determine the optimal topology that maximises the heat transfer. Unlike the constructed theory, the present investigation considers heat dissipation potential function as the objective function, whose gradient field is taken as the criterion for allocation of the limited amount of high conductivity material over the domain. The considered domain is rectangular in geometry, where all its sides are insulated except a centrally located patch on one of the sides, which is maintained at a constant temperature. FEM is used to compute the temperature and it is supplied to the topology optimization algorithm to determine the distribution of material with varied thermal conductivity over the domain. Grid independency is performed for five different grid sizes varying from 10x10 to 90x90. The variation of computation time and objective function with mesh refinement is reported.
Thermophysical Properties of Pongama Honge Oil Methyl Ester and Rubber Seed Oil Methyl Ester for Wide Temperature Range
Authors: Moulali Shaik , Hanumantha Rao Y.V. , Atgur Vinay , Manvendra G. , Desai G.P.
Published: January 2020

Thermal energy is used in the process of heating, cooling and product design purpose. In this work, two non-edible oils are considered and their thermal conductivity, specific heat and thermal degradation are experimentally determined as a function of temperature using, guarded hot plate method, differential scanning calorimetry (DSC) and thermogravtic analyser (TGA). Miniature difference between the obtained and actual thermal conductivity values are influenced by the fatty acid composition. In the present work Pongamia Honge Oil Methyl Ester (HOME) and Rubber Seed Oil Methyl Ester (ROME) are studied and their properties are determined experimentally for a temperature range of 25 to 80ï‚°C. It has been observed that thermal conductivity of HOME decreases from 0.168 to 0.124 W/mK and for ROME thermal conductivity decreases from 0.143 to 0.113 W/mK. Thermal degradation and specific heat were studied using TGA and DSC. Specific heat was studied in the range from 35 to 120 C. For HOME, the specific heat varies from 2.345 to 2.64 kJ/kgK. For ROME, the specific heat varies from 1.572 to 1.992 kJ/kgK.
Performance Analysis of Shell and Tube Heat Exchanger using Different Nanofluids
Authors: Thavamani J.
Published: January 2020

Heat exchanger is the most important function in industrial sector for transferring heat energy to useful work. Heat transfer occurs between the cold fluid and hot fluid or from hot fluid to cold fluid in conduction and convection mode of through a heat exchanger wall. If heat transfer medium has very low thermal conductivity, it would have limited the efficiency of heat exchanger. Whenever the system is subjected to increased heat load, cooling is the main technical challenge for industries. The main objective of this work is to evaluate the effectiveness of shell and tube heat exchanger experimentally and analyse the flow behaviours of different nanofluids. In our experimental analysis, various nanofluids which consist of water and one percentage volume concentration of Al2O3, CuO and SiO2 passing through tube side in the shell and tube heat exchanger. The nano particle diameter is 70nm. The three dissimilar mass flow rates are considered for the experiments and their results are continuously monitored. The enhancement of heat transfer performance of CuO, Al2O3, SiO2 is compared with the base fluid water. Reynolds number values are calculated with three different mass flow rates and compared with heat transfer characteristics (LMTD, Nusselt number and overall heat transfer coefficient). SEM analysis, energy dispersive spectroscopy, X-ray diffraction of CuO, Al2O3 and SiO2.are conducted. The heat transfer effectiveness is increased by 22.12%, 19.46% and 1.47% respectively for CuO, Al2O3 and SiO2 when compared to base fluid.
Análisis y caracterización de la frecuencia de enlace por retro-dispersión en sistemas UHF-RFID pasivos
Authors: Blanco J. , García A. , Cañas V.
Published: January 2020

La tecnología de identificación por radiofrecuencia (RFID) es clave para la visualización de cada objeto en el marco de la Internet de las Cosas. Y más concretamente, la tecnología pasiva es la más extendida e implantada, ya que un lector puede identificar multitud de etiquetas en un corto periodo de tiempo. Cada etiqueta responde al lector a través de una subportadora denominada Frecuencia de Enlace por Retro-dispersión (Backscatter-Link Frequency, BLF). Con el objetivo de caracterizar este parámetro, en este artículo se emplea un conjunto de pruebas para evaluar la aleatoriedad de valores de BLF medidos y obtenidos de etiquetas comerciales. Los resultados muestran grandes variaciones de este parámetro respecto al primer valor esperado por el lector, así como durante el proceso de comunicación. Este comportamiento puede ser aprovechado como una característica diferenciadora de cada etiqueta y puede emplearse en los procesos de comunicación u otros fines. Consiguiendo, en definitiva, etiquetas pasivas más eficientes.
Generación automática de problemas de diseño de controladores para sistemas lineales autoevaluables con Doctus
Authors: Sánchez C. , Muñoz de la Peña D. , Gómez-Estern F.
Published: January 2020

En este trabajo se presenta una aplicación que permite a un profesor generar de forma automática ejercicios de diseño de controladores para sistemas lineales para la plataforma de e-learning Doctus. Doctus es una aplicación que permite automatizar la recogida, almacenamiento y evaluación de ejercicios de contenido científico-técnico. En general, para utilizar Doctus es necesario escribir scripts de MATLAB, tanto para la evaluación automàtica de la respuesta de los alumnos como para la generación de enunciados personalizados. La aplicación que se presenta es una extensión de Doctus destinada a simplificar este trabajo, permitiendo generar ejercicios personalizados mediante la aplicación de un escalado temporal y de ganancia a partir de un problema semilla que proporciona el profesor. La aplicación presentada resuelve, por lo tanto, dos problemas: primero el de facilitar el uso de Doctus a profesores no expertos, y segundo el de proporcionar a cada estudiante un ejercicio individualizado con solución y dificultad garantizadas.
Arquitectura dual-modular para desarrollos y validación de módulos de decisión y control en vehículos automatizados
Authors: Lattarulo R. , Matute J. A. , Pérez J. , Gomez Garay V.
Published: January 2020

El avance logrado durante las últimas décadas en los sistemas avanzados de asistencia a la conducción (ADAS, Advanced Driver Assistance System) ha posibilitado mejorar múltiples aspectos en los vehículos comerciales, como por ejemplo la seguridad, robustez de los sistemas, eficiencia energética, detección de peatones, aparcamiento asistido y ayudas a la navegación, entre otros. Algunos desarrollos, como el control lateral y la generación óptima de trayectorias en tiempo real, están en pleno desarrollo. En este trabajo se presenta una arquitectura dual-modular cuyas principales características son su capacidad para integrar y probar nuevos algoritmos de control y decisión (modular), y la posibilidad de llevar a cabo pruebas en entornos simulados y en plataformas reales (dual), reduciendo los tiempos y costes de desarrollo. Con esta arquitectura se han podido probar diferentes técnicas de control y de generación de trayectorias, realizando además simulaciones, y comparando los resultados obtenidos con un vehículo real.
Pulmonary complications following cardiac surgery
Authors: Mali Shahriar , Haghaninejad Hasan
Published: January 2020

Coronary heart disease is a common diseases of atherosclerosis. Despite the development of noninvasive therapies and the advancement of pharmacological methods and extensive drug regimens, coronary artery bypass grafting surgery is still the ultimate treatment option in many patients. Among the various complications following open heart surgery, one of the common difficulties is pulmonary complications associated with subsequent morbidity and mortality, which should be studied according to preoperative, perioperative, and postoperative factors. Preoperative factors include genetics, age, family history of pulmonary disease, smoking, coexisting disease, etc. Perioperative factors include surgical procedures like sternotomy incision, cardioplegia, and internal mammary artery harvesting; anaesthesia procedure effects like pulmonary collapse, maintenance drugs and morphine administration; and cardiopulmonary bypass pump by systemic inflammatory response syndromes. And finally, postoperative factors, especially mediastinitis and the role of nursing in the intensive care unit. Pulmonary complications after cardiac surgery include atelectasis, pleural effusions, pneumonia, pulmonary oedema, cardiogenic pulmonary oedema, acute respiratory distress syndrome, pulmonary embolism, phrenic nerve injury, pneumothorax, sternal wound infection, and mediastinitis, with different outbreaks in patients reported. Although the preoperative, perioperative, and postoperative factors play an important role in the occurrence of these complications, the preoperative factors, as factors that can be adjusted, should be considered more than the others and explained to the patient, and the preoperative patient’s assessment should be noted. Also, postoperative care with the goal of reducing infections and pulmonary complications should be addressed by the nursing team.