21 research outputs found
On "bettering humanity" in science and engineering education
Science and Engineering Ethics, 13(2): pp. 265-273.Authors such as Krishnamany Selvan argue that “all human endeavors including engineering and science” have a single primary objective: “bettering humanity.” They favor discussing “the history of science and measurement uncertainty.” This paper respectfully disagrees and argues that “human endeavors including engineering and science” should not pursue “bettering humanity” as their primary objective. Instead these efforts should first pursue individual betterment. One cannot better humanity without knowing what that means. However, there is no one unified theory of what is to the betterment of humanity. Simultaneously, there is no one field (neither science, nor engineering, nor philosophy) entitled to rule univocally. Perhaps if theorists tended their own gardens, the common weal would be tended thereby
Expert Elicitation of the Value per Statistical Life in an Air Pollution Context
The monetized value of avoided premature mortality typically dominates the calculated benefits of air pollution regulations; therefore, characterization of the uncertainty surrounding these estimates is key to good policymaking. Formal expert judgment elicitation methods are one means of characterizing this uncertainty. They have been applied to characterize uncertainty in the mortality concentration-response function, but have yet to be used to
characterize uncertainty in the economic values placed on avoided mortality. We report the findings of a pilot expert judgment study for Health Canada designed to elicit quantitative probabilistic judgments of uncertainties in Value-per-Statistical-Life (VSL) estimates for use in an air pollution context. The two-stage elicitation addressed uncertainties in both a base
case VSL for a reduction in mortality risk from traumatic accidents and in benefits transferrelated adjustments to the base case for an air quality application (e.g., adjustments for age, income, and health status). Results for each expert were integrated to develop example quantitative probabilistic uncertainty distributions for VSL that could be incorporated into air
quality models
Long-Term Clinical Safety of High-Dose Proton Radiation Therapy Delivered With Pencil Beam Scanning Technique for Extracranial Chordomas and Chondrosarcomas in Adult Patients: Clinical Evidence of Spinal Cord Tolerance.
PURPOSE
To assess the radiation dose tolerance of the spinal cord by reviewing our institutional experience regarding the incidence of radiation-induced spinal cord toxicity after high-dose pencil beam scanning proton therapy (PBSPT).
METHODS AND MATERIALS
Seventy-six patients (median age 53 years; range, 23-79 years) treated for spinal chordoma (n=55) or chondrosarcoma (n=21) met the following criteria and were retrospectively analyzed: PBSPT only, no reirradiation or concomitant chemotherapy, maximum dose (Dmax) to the spinal cord of ≥45 Gy(relative biological effectiveness [RBE]), ≥18 years of age, and follow-up of ≥12 months. The delivered dose was 59.4 to 75.2 Gy(RBE) [median 73.9 Gy(RBE)] delivered with conventional fractionation between 2000 and 2014. The Dmax, D2%, and V40-V60 of the surface (sSC) and center (cSC) of the spinal cord were recorded. Toxicity was scored according to the Common Terminology Criteria for Adverse Events, version 4.03.
RESULTS
Median follow-up was 65.5Â months (range, 13-173Â months). Patients received a mean Dmax and D2% to the sSC of 59.0 (median 58.7; range, 48.3-75.9) and 55.3 (median 52.7; range, 43.1-73.8) Gy(RBE), respectively. The corresponding values for the cSC were 52.3 (median 52.7; range, 32.3-73.3) and 51.1 (median 52.0; range, 25.3-73.1) Gy(RBE), respectively. Four patients (5%) developed acute radiation-induced neurotoxicity (grade [G] 1, n=1; G2, n=3). Twelve patients (16%) experienced late neurologic toxicities (G1, n=7; G2, n=4; G4, n=1). One patient with a history of pre-PBSPT symptomatic spinal cord compression redeveloped tetraplegia (G4) after receiving a Dmax of 57.8Â Gy(RBE) to the sSC and 54.1Â Gy(RBE) to the cSC. No significant correlation was found between sSC Dmax and D2%, cSC Dmax and D2%, or the length of CTV and toxicity.
CONCLUSIONS
High-dose conformal PBSPT may be delivered safely in close proximity to the spinal cord with minimal neurotoxicity. Dose constraints of 64Â Gy(RBE) as D2% for the sSC and 54Â Gy(RBE) for the cSC seem appropriate for clinical use
Impacts of Air Cleaners on Indoor Air Quality in Residences Impacted by Wood Smoke
Residential wood
combustion is an important source of ambient air
pollution, accounting for over 25% of fine particulate matter (PM<sub>2.5</sub>) emissions in Canada. In addition to these ambient contributions,
wood smoke pollutants can enter the indoor environment directly when
loading or stoking stoves, resulting in a high potential for human
exposure. A study of the effectiveness of air cleaners at reducing
wood smoke-associated PM<sub>2.5</sub> of indoor and outdoor origin
was conducted in 31 homes during winter 2009–10. Day 1, the
residents’ wood burning appliance operated as usual with no
air cleaner. Days 2 and 3, the wood burning appliance was not operational
and the air cleaner was randomly chosen to operate in “filtration”
or “placebo filtration” mode. When the air cleaner was
operating, total indoor PM<sub>2.5</sub> levels were significantly
lower than on placebo filtration days (<i>p</i> = 0.0001)
resulting in a median reduction of 52%. There was also a reduction
in the median PM<sub>2.5</sub> infiltration factor from 0.56 to 0.26
between these 2 days, suggesting the air cleaner was responsible for
increased PM<sub>2.5</sub> deposition on filtration days. Our findings
suggest that the use of an air cleaner reduces exposure to indoor
PM<sub>2.5</sub> resulting from both indoor and ambient wood smoke
sources