Factors Related to Performance Variation Among Logging-Machine Operators

La performance et le rendement des opérateurs de machines utilisées en exploitation forestière varient considérablement. Les compagnies forestières désirent évidemment embaucher des opérateurs qui fourniront un rendement élevé et soutenu. Elles aimeraient également pouvoir sélectionner et former des stagiaires aptes à devenir d'excellents opérateurs. L'embauche, la mobilité de la main d'oeuvre et la formation professionnelle sont des activités coûteuses et les employeurs cherchent donc des méthodes de sélection qui faciliteraient le choix des candidats les plus prometteurs. Une sélection plus efficace est possible à condition de mieux comprendre comment certaines caractéristiques d'un opérateur telles qu'aptitudes physiques et intellectuelles, histoire personnelle, motivation et expérience peuvent influer sur son rendement au travail.Les variations dans le rendement de 34 opérateurs de machines équipées de sécateurs hydrauliques sont le sujet de la présente étude dont les buts étaient de: (1) documenter les variations dans le rendement et de mesurer la variabilité « intra-opérateurs », « inter-opérateurs » et « inter-compagnies » ; (2) établir la relation entre les caractéristiques de l'opérateur et son rendement; et (3) proposer des méthodes susceptibles d'augmenter les niveaux moyens de rendement.Ces études, effectuées dans le centre-nord de la Colombie Britannique au cours de la période juin-décembre 1973, ont fourni des données sur 757 quarts d'abattage dans 86 parterres de coupe identifiés. Durant chaque quart d'abattage d'une durée moyenne de 6.2 heures-machines productives (HMP), 115 arbres par HMP furent abattus pour une production moyenne totale de 701 arbres marchands. Le niveau moyen de production par opérateur variait de moins de 50 à plus de 150 arbres par HMP.L'analyse des données a démontré qu'environ V3 de la variabilité dans le rendement était imputable aux différences quotidiennes intra-opérateurs et qu'environ2h était attribuable aux différences inter-opérateurs... La variabilité inter-compagnie s'est avérée presque nulle.Des entrevues et tests ont fourni des renseignements sur l'histoire personnelle, l'expérience professionnelle, l'attitude, la motivation, et sur certaines caractéristiques physiques et intellectuelles des opérateurs.Compte tenu des différences entre les conditions de peuplement, des ajustements furent effectués et il fut ensuite possible d'établir une relation significative entre le rendement et les caractéristiques suivantes de l'opérateur:— perception des distances— durée de l'expérience sur la machine en cause— dextérité manuelle— degré de motivationLa perception des distances, l'expérience et la dextérité manuelle pourraient facilement être évaluées au cours d'un procédé de sélection. La motivation est plus immédiatement influencée par la modification des structures d'organisation et de supervision à l'intérieur de chaque compagnie.Les suggestions proposées pour accélérer la progression des travaux dans ce domaine sont:— Le développement de procédés pour évaluer non seulement les aspects quantitatifs, mais aussi les aspects qualitatifs du rendement, dans divers emplois de l'exploitation forestière.— L'amélioration des modèles théoriques établissant la relation entre les caractéristiques des opérateurs et des groupes de travail en rapport avec le rendement.— L'examen des facteurs humains dans la conception de machines (ergonomie) pour augmenter le rendement au travail, diminuer le temps de formation, améliorer la sécurité au travail et le bien-être des opérateurs.— La préparation d'un recueil de renseignements sur les techniques supérieures de travail dans divers emplois pour le bénéfice des opérateurs et des contremaîtres à tous les niveaux.— La formulation d'un programme pratique pour vérifier l'utilité des procédés d'évaluation du personnel afin de prédire le rendement éventuel de nouveaux employés, ou de stagiaires, dans divers emplois de l'exploitation forestière.Despite the economic importance of large variations in individual productivity of logging-machine operators, few studies have attempted to examine the source of such variations. Based on data obtained for a total of 757 shifts of tree-felling activity, this exploratory study attempted to: (a) document variation in on-the-job performance and assign the variation to sources « within individual operators », « between operators », or « between firms »; (b) relate ob-served performance measured operator characteristics (ability and motivation); and (c) suggest ways in which average levels of job performance could be improved

Experiences in fosfomycin susceptibility testing and resistance mechanism determination in Escherichia coli from urinary tract infections in the UK

PURPOSE: With an increase in the numbers of bacterial isolates resistant to first-line antibiotics, there has been a revival in the use of older drugs including fosfomycin with novel mechanisms of action. We aimed to investigate the prevalence and genotypic nature of fosfomycin resistance in Escherichia coli from urinary tract infections (UTIs) using the various methods available in the clinical microbiology laboratory. METHODOLOGY: In total, 1000 culture-positive urine samples were assessed for the presence of E. coli and fosfomycin susceptibility was determined using the MAST Uri system, microbroth dilution, agar dilution and E-test strips.Results/Key findings. Initial investigation using breakpoint susceptibility testing on the MAST Uri system identified 62 of 657 (9.5 %) E. coli isolates as fosfomycin-resistant (MIC≥32 µg ml-1). However, on further testing, a lower rate of eight of the 62 (1.3 %) were robustly confirmed to be resistant using microbroth dilution, agar dilution and E-test strips. These true resistant isolates belonged to diverse E. coli multi-locus sequence types and each had a unique set of chromosomal alterations in genes associated with fosfomycin resistance. Fosfomycin-resistant isolates were not multiply drug resistant and did not carry plasmidic fosfomycin resistance genes. Therefore, the use of fosfomycin may be unlikely to drive selection of a particular clone or movement of transferable resistance genes. CONCLUSION: Fosfomycin remains a viable option for the treatment of E. coli in uncomplicated UTIs; different susceptibility testing platforms can give very different results regarding the prevalence of fosfomycin resistance, with false positives being a potential problem that may unnecessarily limit the use of this agent

An Empirical Examination Of Pension Rate Estimates: A Benchmark Approach

In this paper, we analyze pension rate choices for a sample of 495 firms over the thirteen-year period from 1994-2006. In recent years, articles have appeared in business publications alleging abuse of the discretion afforded to management in setting pension rates, particularly the pension discount rate and expected rate of return on plan assets. We find that pension discount rate estimates and expected rate of return estimates generally comply with the authoritative requirements, although there appears to be a smoothing effect in setting pension discount rates as well as a lag in fully reflecting economic conditions. We find evidence consistent with discount rate choice being influenced by deteriorating economic conditions, and possibly passage of the Sarbanes-Oxley Act. We also find that, in general, firms’ expected rate of return assumptions tend to reflect their long-run internal rates of return on pension assets, although the recessionary influences in the early 2000s were not fully reflected in the expected rates of return toward the end of our test period. There is also a sizeable minority of firms (approximately 27%) for which their expected rates of return on plan assets consistently overstate their actual, long-run returns

Coupling dye-integrated polymeric membranes with smartphone detection to classify bacteria

We report the use of a colorimetric plastic-based device to discriminate four pathogenic bacteria: Klebsiella pneumoniae, Proteus vulgaris, Proteus mirabilis and Escherichia coli. The colour changes of the plastic membranes were analysed with RGB values extracted from dye-integrated polymeric membrane images obtained with a smartphone and used as input data for non-supervised pattern recognition methods. © The Royal Society of Chemistry 2015

Rational Prediction Of Future Pension Expense: A Simulation Approach

Because future pension expense can have a material influence on a firm’s future earnings, financial analysts are faced with the difficult task of forecasting its impact.  The purpose of this paper is to demonstrate a model that can be used with a simulation approach to predict future pension expense and its associated uncertainties.  Because of the importance and complexity of the pension expense component in the estimate of future earnings, a simulation model acts as a powerful analytical tool that can give the analyst greater confidence as to the magnitude and variability of future pension expense

A new approach to transitive expletives: Evidence from Belfast English

This article discusses the existence of transitive expletives in a variety of English. Belfast English has none of the features previously proposed as licensing transitive expletives, but nevertheless allows these, calling into question previous analyses of the licensing of this structure. This article considers the properties of transitive expletives in this variety, showing that they are restricted to sentences where the associate is quantified, and that the associate can appear in a range of positions, similar but not identical to those available to 'floated' quantifiers. It is argued that Belfast English has a higher merge position for the expletive than does Standard English, and that the general availability in English of quantifier positions between T and vP -perhaps because auxiliaries in English head phases, and phases can be closed by a quantification -means that, even though Belfast English is not a Verb Second language, a position is available for both the expletive and the associate

Topical arnica and mucopolysaccharide polysulfate (hirudoid) to decrease bruising and pain associated with haemodialysis cannulation - related infiltration: a pilot study

ABSTRACTBackground:&nbsp;Topical treatments such as Arnica cream and mucopolysaccharide polysulfuric acid (contained in Hirudoid&nbsp;cream) have been used to treat the bruising and pain arising from dialysis-related infiltrations.Aim:&nbsp;To undertake a randomised controlled pilot study comparing the efficacy of Arnica and Hirudoid creams in treating&nbsp;bruising and pain following post-needling infiltration.Methods:&nbsp;One dialysis centre of 40 patients over a 12-month period. Following infiltration, and at the five subsequent dialysis&nbsp;treatments, pain was measured using the Abbey pain scale and size of the bruise was recorded.Results:&nbsp;Eleven cases of infiltration were recorded consisting of seven males (64%) and four females (36%) who had a mean age&nbsp;of 78 years (SD=9). Access for eight patients was via arteriovenous fistula and for three patients via arteriovenous graft. Eight&nbsp;patients experienced bruising and two patients reported mild pain post-infiltration but there were no differences found between&nbsp;the effect of Arnica or Hirudoid in treating either symptom.Conclusion:&nbsp;This pilot study was unable to detect any differences in the effect of Arnica and Hirudoid on pain or bruising. The&nbsp;study demonstrated that a larger, multicentre trial would be required to power a study and that a non-interventional control&nbsp;group should be added.</div

Functional genomics to identify the factors contributing to successful persistence and global spread of an antibiotic resistance plasmid

Background: The spread of bacterial plasmids is an increasing global problem contributing to the widespread dissemination of antibiotic resistance genes including β-lactamases. Our understanding of the details of the biological mechanisms by which these natural plasmids are able to persist in bacterial populations and are able to establish themselves in new hosts via conjugative transfer is very poor. We recently identified and sequenced a globally successful plasmid, pCT, conferring β-lactam resistance. Results: Here, we investigated six plasmid encoded factors (tra and pil loci; rci shufflon recombinase, a putative sigma factor, a putative parB partitioning gene and a pndACB toxin-antitoxin system) hypothesised to contribute to the 'evolutionary success' of plasmid pCT. Using a functional genomics approach, the role of these loci was investigated by systematically inactivating each region and examining the impact on plasmid persistence, conjugation and bacterial host biology. While the tra locus was found to be essential for all pCT conjugative transfer, the second conjugation (pil) locus was found to increase conjugation frequencies in liquid media to particular bacterial host recipients (determined in part by the rci shufflon recombinase). Inactivation of the pCT pndACB system and parB did not reduce the stability of this plasmid. Conclusions: Our findings suggest the success of pCT may be due to a combination of factors including plasmid stability within a range of bacterial hosts, a lack of a fitness burden and efficient transfer rates to new bacterial hosts rather than the presence of a particular gene or phenotype transferred to the host. The methodology used in our study could be applied to other 'successful' globally distributed plasmids to discover the role of currently unknown plasmid backbone genes or to investigate other factors which allow these elements to persist and spread

Joubert syndrome Arl13b functions at ciliary membranes and stabilizes protein transport in Caenorhabditis elegans

The small ciliary G protein Arl13b is required for cilium biogenesis and sonic hedgehog signaling and is mutated in patients with Joubert syndrome (JS). In this study, using Caenorhabditis elegans and mammalian cell culture systems, we investigated the poorly understood ciliary and molecular basis of Arl13b function. First, we show that Arl13b/ARL-13 localization is frequently restricted to a proximal ciliary compartment, where it associates with ciliary membranes via palmitoylation modification motifs. Next, we find that loss-of-function C. elegans arl-13 mutants possess defects in cilium morphology and ultrastructure, as well as defects in ciliary protein localization and transport; ciliary transmembrane proteins abnormally accumulate, PKD-2 ciliary abundance is elevated, and anterograde intraflagellar transport (IFT) is destabilized. Finally, we show that arl-13 interacts genetically with other ciliogenic and ciliary transport-associated genes in maintaining cilium structure/morphology and anterograde IFT stability. Together, these data implicate a role for JS-associated Arl13b at ciliary membranes, where it regulates ciliary transmembrane protein localizations and anterograde IFT assembly stability