SYSTEM RESPONSE TIME, OPERATOR PRODUCTIVITY AND JOB SATISFACTION

This study examines the impact of on-line system response time on CRT operator productivity and job satisfaction. It was predicted that increase in response time would affect total transaction volume and total errors adversely, that is, total transaction volume would decrease with longer response times and total errors would increase. Total productive transactions, the difference between total transactions and total errors, was expected to decrease as response time increased. Operator job satisfaction was also expected to decrease. The study confirmed the prediction with regard to total transactions and productive transactions: both decreased as response time increased. Total errors actually decreased as response time increased, up to times of 12 seconds. When response time exceeded 12 seconds, errors increased. The impact of response time on productivity suggests nearly all transactions should be completed in 12 seconds or less. Beyond this level, the organization in the study suffered severe penalties in lost productivity. A relationship was also found between increased response times and reduced job satisfaction.Information Systems Working Papers Serie

Analysis of reapplications made to the Worcester Children's Friend Society from October 1931 to October 1941

This item was digitized by the Internet Archive. Thesis (M.S.)--Boston Universityhttps://archive.org/details/analysisofreappl00bro

Reliability training

Discussed here is failure physics, the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low cost reliable products. A review of reliability for the years 1940 to 2000 is given. Next, a review of mathematics is given as well as a description of what elements contribute to product failures. Basic reliability theory and the disciplines that allow us to control and eliminate failures are elucidated

Temporally and genetically discrete periods of wheat sensitivity to high temperature

Successive single day transfers of pot-grown wheat to high temperature (35/30oC day/night) replicated controlled environments, from the second node detectable to the milky-ripe growth stages, provides the strongest available evidence that the fertility of wheat can be highly vulnerable to heat stress during two discrete peak periods of susceptibility: early booting (decimal growth stage (GS) 41-45) and early anthesis (GS 61-65). A double Gaussian fitted simultaneously to grain number and weight data from two contrasting elite lines (Renesansa, listed in Serbia, Ppd-D1a, Rht8; Savannah, listed in UK, Ppd-D1b, Rht-D1b) identified peak periods of main stem susceptibility centred on 3 (s.e.= 0.82) and 18 (s.e. = 0.55) days (mean daily temperature = 14.3oC) pre-GS 65 for both cultivars. Severity of effect depended on genotype, growth stage and their interaction: grain set relative to that achieved at 20/15oC dropped below 80% for Savannah at booting and Renesansa at anthesis. Savannah was relatively tolerant to heat stress at anthesis. A further experiment including 62 lines of the mapping, doubled-haploid progeny of Renesansa x Savannah found tolerance at anthesis to be associated with Ppd-D1b, Rht-D1b, and a QTL from Renesansa on chromosome 2A. None of the relevant markers were associated with tolerance during booting. Rht8 was never associated with heat stress tolerance, a lack of effect confirmed in a further experiment where Rht8 was included in a comparison of near isogenic lines in a cv. Paragon background. Some compensatory increases in mean grain weight were observed, but only when stress was applied during booting and only where Ppd-D1a was absent

Identifying beneficial traits for heat stress around reproductive phases of growth in wheat

There is a need for heat tolerant traits in wheat to be identified in order to maintain and increase yields in future climates. The aim of this project was to assess genotypic variation in crop response to heat stress by comparing a southern European wheat genotype (Renesansa; Rht-D1a, Rht8, Ppd-D1a) with a UK genotype (Savannah; RhtD1b, Ppd-D1b, 1BL/1RS) and their doubled haploid progeny. This would allow for the identification of traits and alleles that would benefit UK and European wheat production under climate change scenarios through the use of a combination of phenotyping, genotyping and crop modelling. Heat stress experiments were conducted in controlled environments to identify the most susceptible growth stages to heat stress within the population and to identify potentially tolerant traits. An appraisal of the crop model SIRIUS and how it simulates heat stress was undertaken. Finally, a field trial was conducted to identify which traits perform well in UK field conditions. Two periods of susceptibility in Savannah and Renesansa were identified as susceptible to heat stress, through reductions in grain number. The first period was identified around booting, with the second being identified one day before mid anthesis. The period around heading was found to be relatively tolerant. Compensation of reduced grain numbers through increases in grain size was limited and variable. Rht8 was not found to influence heat stress tolerance. The photoperiod insensitivity allele Ppd-D1a was found to increase susceptibility to heat stress, while the semi dwarfing allele Rht-D1b was found to confer tolerance to it. Rht8 was associated with reduced yield in UK field conditions. Simulations from SIRIUS suggest that yield loss due to heat stress could increase by three fold in central Europe by 2090, though it is not expected to be a major issue in the UK

Incompressible Quantum Liquids and New Conservation Laws

In this letter we investigate a class of Hamiltonians which, in addition to the usual center-of-mass (CM) momentum conservation, also have center-of-mass position conservation. We find that regardless of the particle statistics, the energy spectrum is at least q-fold degenerate when the filling factor is $p/q$, where $p$ and $q$ are coprime integers. Interestingly the simplest Hamiltonian respecting this type of symmetry encapsulates two prominent examples of novel states of matter, namely the fractional quantum Hall liquid and the quantum dimer liquid. We discuss the relevance of this class of Hamiltonian to the search for featureless Mott insulators.Comment: updated version, to be published by PR

The Changing Climate of the Arctic

The first and strongest signs of global-scale climate change exist in the high latitudes of the planet. Evidence is now accumulating that the Arctic is warming, and responses are being observed across physical, biological, and social systems. The impact of climate change on oceanographic, sea-ice, and atmospheric processes is demonstrated in observational studies that highlight changes in temperature and salinity, which influence global oceanic circulation, also known as thermohaline circulation, as well as a continued decline in sea-ice extent and thickness, which influences communication between oceanic and atmospheric processes. Perspectives from Inuvialuit community representatives who have witnessed the effects of climate change underline the rapidity with which such changes have occurred in the North. An analysis of potential future impacts of climate change on marine and terrestrial ecosystems underscores the need for the establishment of effective adaptation strategies in the Arctic. Initiatives that link scientific knowledge and research with traditional knowledge are recommended to aid Canada’s northern communities in developing such strategies.Les premiers signes et les signes les plus révélateurs attestant du changement climatique qui s’exerce à l’échelle planétaire se manifestent dans les hautes latitudes du globe. Il existe de plus en plus de preuves que l’Arctique se réchauffe, et diverses réactions s’observent tant au sein des systèmes physiques et biologiques que sociaux. Les incidences du changement climatique sur les processus océanographiques, la glace de mer et les processus atmosphériques s’avèrent évidentes dans le cadre d’études d’observation qui mettent l’accent sur les changements de température et de salinité, changements qui exercent une influence sur la circulation océanique mondiale – également appelée circulation thermohaline – ainsi que sur le déclin constant de l’étendue et de l’épaisseur de glace de mer, ce qui influence la communication entre les processus océaniques et les processus atmosphériques. Les perspectives de certains Inuvialuits qui ont été témoins des effets du changement climatique font mention de la rapidité avec laquelle ces changements se produisent dans le Nord. L’analyse des incidences éventuelles du changement climatique sur les écosystèmes marin et terrestre fait ressortir la nécessité de mettre en oeuvre des stratégies d’adaptation efficaces dans l’Arctique. Des initiatives reliant les recherches et connaissances scientifiques aux connaissances traditionnelles sont recommandées afin de venir en aide aux collectivités du Nord canadien pour que celles-ci puissent aboutir à de telles stratégies

SYSTEM RESPONSE TIME, OPERATOR PRODUCTIVITY AND JOB SATISFACTION

This study examines the impact of on-line system response time on CRT operator productivity and job satisfaction. It was predicted that increase in response time would affect total transaction volume and total errors adversely, that is, total transaction volume would decrease with longer response times and total errors would increase. Total productive transactions, the difference between total transactions and total errors, was expected to decrease as response time increased. Operator job satisfaction was also expected to decrease. The study confirmed the prediction with regard to total transactions and productive transactions: both decreased as response time increased. Total errors actually decreased as response time increased, up to times of 12 seconds. When response time exceeded 12 seconds, errors increased. The impact of response time on productivity suggests nearly all transactions should be completed in 12 seconds or less. Beyond this level, the organization in the study suffered severe penalties in lost productivity. A relationship was also found between increased response times and reduced job satisfaction.Information Systems Working Papers Serie

Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS

We present Hubble Space Telescope near-infrared transit photometry of the nearby hot-Jupiter HD189733b. The observations were taken with the NICMOS instrument during five transits, with three transits executed with a narrowband filter at 1.87 microns and two performed with a narrowband filter at 1.66 microns. Our observing strategy using narrowband filters is insensitive to the usual HST intra-orbit and orbit-to-orbit measurement of systematic errors, allowing us to accurately and robustly measure the near-IR wavelength dependance of the planetary radius. Our measurements fail to reproduce the Swain et al. absorption signature of atmospheric water below 2 microns at a 5-sigma confidence level. We measure a planet-to-star radius contrast of 0.15498+/-0.00035 at 1.66 microns and a contrast of 0.15517+/-0.00019 at 1.87 microns. Both of our near-IR planetary radii values are in excellent agreement with the levels expected from Rayleigh scattering by sub-micron haze particles, observed at optical wavelengths, indicating that upper-atmospheric haze still dominates the near-IR transmission spectra over the absorption from gaseous molecular species at least below 2 microns.Comment: 9 pages, 7 figures. Accepted for publication in A&

Nightside Pollution of Exoplanet Transit Depths

Out of the known transiting extrasolar planets, the majority are gas giants orbiting their host star at close proximity. Both theoretical and observational studies support the hypothesis that such bodies emit significant amounts of flux relative to the host star, increasing towards infrared wavelengths. For the dayside of the exoplanet, this phenomenon typically permits detectable secondary eclipses at such wavelengths, which may be used to infer atmospheric composition. In this paper, we explore the effects of emission from the nightside of the exoplanet on the primary transit lightcurve, which is essentially a self-blend. Allowing for nightside emission, an exoplanet's transit depth is no longer exclusively a function of the ratio-of-radii. The nightside of an exoplanet is emitting flux and the contrast to the star's emission is of the order of ~10^(-3) for hot-Jupiters. Consequently, we show that the transit depth in the mid-infrared will be attenuated due to flux contribution from the nightside emission by ~10^(-4). We show how this effect can be compensated for in the case where exoplanet phase curves have been measured, in particular for HD 189733b. For other systems, it may be possible to make a first-order correction by using temperature estimates of the planet. Unless the effect is accounted for, transmission spectra will also be polluted by nightside emission and we estimate that a Spitzer broadband spectrum on a bright target is altered at the 1-sigma level. Using archived Spitzer measurements, we show that the effect respectively increases the 8.0um and 24.0um transit depths by 1-sigma and 0.5-sigma per transit for HD 189733b. Consequently, we estimate that this would be 5-10 sigma effect for near-future JWST observations.Comment: Accepted in MNRA