Comparison of work rates, energy expenditure, and perceived exertion during a 1-h vacuuming task with a backpack vacuum cleaner and an upright vacuum cleaner

The purpose of this study was to evaluate two types of industrial vacuum cleaners, in terms of cleaning rates, energy expenditure, and perceived exertion. Twelve industrial cleaners (six males and six females, age 28-39 yr) performed two 1-h vacuuming tasks with an upright vacuum cleaner (UVC) and a backpack vacuum cleaner (BPVC). Measures for oxygen uptake (VO2) and ratings of perceived exertion (RPE) were collected continuously during the 1-h vacuuming tasks. Cleaning rates for the UVC and BPVC were 7.23 and 14.98 m2min(-1), respectively. On a separate day subjects performed a maximal treadmill exercise test to determine their maximal aerobic capacity (peak VO2). Average absolute energy costs (in Metabolic equivalents), relative energy costs of the vacuum task compared to the subjects' maximal aerobic capacity (% peak VO2), and RPE responses for the 1-h vacuuming tasks were similar between vacuum cleaners, but % peak VO2 and RPE values differed between genders. These results indicate that the BPVC was more efficient than the UVC. With the BPVC, experienced workers vacuumed at a cleaning rate 2.07 times greater than the UVC and had similar levels of energy expenditure and perceived effort, compared to the slower cleaning rate with the UVC.     

A technique for fractionated stereotactic radiotherapy in the treatment of intracranial tumors

PURPOSE: The excellent treatment results obtained with traditional radiosurgery have stimulated attempts to broaden the range of intracranial disorders treated with radiosurgical techniques. For major users of radiosurgery this resulted in a gradual shift from treating vascular diseases in a single session to treating small, well delineated primary tumors on a fractionated basis. In this paper we present the technique currently used in Montreal for the fractionated stereotactic radiotherapy of selected intracranial lesions. METHODS AND MATERIALS: The regimen of six fractions given every other day has been in use for "fractionated stereotactic radiotherapy" in our center for the past 5 years. Our current irradiation technique, however, evolved from our initial method of using the stereotactic frame for target localization and first treatment, and a "halo-ring" with tattoo skin marks for the subsequent treatments. Recently, we developed a more precise irradiation technique, based on an in-house-built stereotactic frame which is left attached to the patient's skull for the duration of the fractionated regimen. Patients are treated with the stereotactic dynamic rotation technique on a 10 MV linear accelerator (linac). RESULTS: In preparation for the first treatment, the stereotactic frame is attached to the patient's skull and the coordinates of the target center are determined. The dose distribution is then calculated, the target coordinates are marked onto a Lucite target localization box, and the patient is placed into the treatment position on the linac with the help of laser positioning devices. The Lucite target localization box is then removed, the target information is tattooed on the patient's skin, and the patient is given the first treatment. The tattoo marks in conjunction with the target information on the Lucite target localization box are used for patient set-up on the linac for the subsequent 5 treatments. The location of the target center is marked with radio-opaque markers on the target localization box and verified with a computerized tomography scanner prior to the second treatment. The same verification is done prior to other treatments when the target center indicated by the target localization box disagrees with that indicated by the tattoo marks. The new position of the target center is then determined and used for treatment positioning. CONCLUSION: The in-house-built frame is inexpensive and easily left attached to the patient's skull for the 12 day duration of the fractionated regimen. Positioning with the Lucite target localization box verified with tattoo marks ensures a high level of precision for individual fractionated treatments.     

Avoidance of bird repellents by mice (Mus musculus)

It is believed that mammalian chemosensory irritants are not aversive to birds and vice versa. Nevertheless, few avian repellents have been tested against mammals. For that reason, we evaluated the efficacy of 1.0% w/v methyl anthranilate, orthoaminoacetophenone, 2-amino-4,5-methoxyacetophenone, 2-methoxyacetophenone, and veratryl amine as mouse repellents in 3-hr no-choice drinking tests. Relative to ingestion of plain water, all test substances significantly reduced (P < 0.05) intake. Orthoaminoaceto-phenone was the most effective repellent, with intake reduced to levels statistically indistinguishable from zero.     

Strategic sensemaking and organizational performance: linkages among scanning, interpretation, action, and outcomes.

This study investigated the strategic "sensemaking" processes of scanning, interpretation, and action and how those activities are linked to organizational performance. Using path analyses on data from 156 hospitals, we tested the direct and indirect effects among these sensemaking processes and performance outcomes and developed a model of their relationships. In a more general sense, the research represents an attempt to provide insight not only into relationships between cognition and action, but also into the links between those fundamental processes and organizational performance outcomes.     

Pressure dependence of T c for lead

The superconducting transition temperature T _c for Pb has been determined as a function of hydrostatic pressure up to 26 kbar. T _c is found to more closely follow a linear pressure dependence, with T _c/P = –(3.61 ± 0.05)× 10^–5K/bar, than a linear volume dependence, as previously reported. The volume dependence of the electron-phonon parameter derived from these measurements, d(ln )/d(ln V) = 4.2 ± 0.1, is in good agreement with theoretical calculations by Ott and Sorbello and by Carbotte and Vashishta. The variation of for larger volume changes is discussed.Supported by the Australian Research Grant Committee.     

Detection of minor constitutents of the stratosphere by far infrared emission spectroscopy

The far infrared (30–110 cm^?1) emission spectrum of the lower stratosphere has been measured from balloon altitudes with a high resolution (0.06 cm^?1) rapid-scanning Michelson interferometer on two flights in 1976. The quality and resolution of the spectra obtained from two altitudes have permitted a careful search for emission lines from environmentally important molecules such as HCl, NO₂, OH, H₂O₂, and CO, among the more prominent and well-known features due to H₂O, O₃ and O₂. Column densities have been determined for H₂O and O₃ and upper limit estimates have been made from tentative identifications of several other constituents. However, the large angular field of view observed by the instrument prevented the determination of concentration profiles from atmospheric limb scans to the horizon. The possible future directions of this technique are outlined on the basis of operating experience over a 6 year programme. The viability of this method of monitoring the concentrations of minor constituents in the stratosphere is discussed with respect to other equivalent techniques.     

Ignitable Liquid Classification and Identification Using the Summed-Ion Mass Spectrum

Abstract

The mass spectra calculated by summing the intensities of each nominal mass over all chromatographic times, the summed ion spectra, were calculated for a set of 440 commercially available ignitable liquids that had been analyzed by gas chromatography–mass spectrometry. Each ignitable liquid is generally comprised of a mixture of chemicals, and the mixtures may be very complex in some cases, e.g., petroleum distillates, gasoline, etc. The summed ion spectra were evaluated to determine if they contained sufficient information content to allow their use for rapid and accurate identification of the ignitable liquid in a database or library. The summed ion nominal mass spectra were encoded in one bit per channel at 1% transition intensity and a set of 96,580 unique pairwise comparisons were made between spectra, resulting in an average of approximately 50 differing channels per comparison. A subset of 62 summed ion spectra were further compared by a similarity metric and found by cluster analysis to group closely along the ASTM ignitable liquid classification scheme. Receiver operator characteristic analysis of the use of the similarity index in combination with the summed ion spectra was shown to provide 99% probability of correct liquid identification and 95% probability of correct ASTM classification by primary and sub-class. Interlaboratory tests found 95% probability of correct liquid identification and 85% probability of correct ASTM classification at the primary class level. These results demonstrate the use of the summed ion spectrum as a first step in the rapid identification of an ignitable liquid by database or library searching.