The results of a multi-year research program to identify the factors associated with variations in subjective workload within and between different types of tasks are reviewed. Subjective evaluations of 10 workload-related factors were obtained from 16 different experiments. The experimental tasks included simple cognitive and manual control tasks, complex laboratory and supervisory control tasks, and aircraft simulation. Task-, behavior-, and subject-related correlates of subjective workload experiences varied as a function of difficulty manipulations within experiments, different sources of workload between experiments, and individual differences in workload definition. A multi-dimensional rating scale is proposed in which information about the magnitude and sources of six workload-related factors are combined to derive a sensitive and reliable estimate of workload.

Development of NASA-TLX (Task Load Index): Results of Empirical and Theoretical Research

ContextModifiable behavioral risk factors are leading causes of mortality in
the United States. Quantifying these will provide insight into the effects
of recent trends and the implications of missed prevention opportunities.ObjectivesTo identify and quantify the leading causes of mortality in the United
States.DesignComprehensive MEDLINE search of English-language articles that identified
epidemiological, clinical, and laboratory studies linking risk behaviors and
mortality. The search was initially restricted to articles published during
or after 1990, but we later included relevant articles published in 1980 to
December 31, 2002. Prevalence and relative risk were identified during the
literature search. We used 2000 mortality data reported to the Centers for
Disease Control and Prevention to identify the causes and number of deaths.
The estimates of cause of death were computed by multiplying estimates of
the cause-attributable fraction of preventable deaths with the total mortality
data.Main Outcome MeasuresActual causes of death.ResultsThe leading causes of death in 2000 were tobacco (435 000 deaths;
18.1% of total US deaths), poor diet and physical inactivity (400 000
deaths; 16.6%), and alcohol consumption (85 000 deaths; 3.5%). Other
actual causes of death were microbial agents (75 000), toxic agents (55 000),
motor vehicle crashes (43 000), incidents involving firearms (29 000),
sexual behaviors (20 000), and illicit use of drugs (17 000).ConclusionsThese analyses show that smoking remains the leading cause of mortality.
However, poor diet and physical inactivity may soon overtake tobacco as the
leading cause of death. These findings, along with escalating health care
costs and aging population, argue persuasively that the need to establish
a more preventive orientation in the US health care and public health systems
has become more urgent.

/pdf/actual-causes-of-death-in-the-united-states-2000-3bff2yf5eo.pdf

Actual causes of death in the United States, 2000.

NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

Pedro Andreo, Dosimetry and Medical Radiation Physics Section, IAEA David T Burns, Bureau International des Poids et Measures (BIPM) Klaus Hohlfeld, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany M Saiful Huq, Thomas Jefferson University, Philadelphia, USA Tatsuaki Kanai, National Institute of Radiological Sciences (NIRS), Chiba, Japan Fedele Laitano, Ente per le Nuove Tecnologie L’Energia e L’Ambiente (ENEA), Rome, Italy Vere Smyth, National Radiation Laboratory (NRL), Christchurch, New Zealand Stefaan Vynckier, Catholic University of Louvain (UCL), Brussels, Belgium

/pdf/absorbed-dose-determination-in-external-beam-radiotherapy-an-53v80q702z.pdf

Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry based on Standards of Absorbed Dose to Water

Transgender and gender non-conforming people face rampant discrimination in every area of life: education, employment, family life, public accommodations, housing, health, police and jails, and ID documents. This data is so shocking that it will change the way you think about transgender people and it should change the way you advocate. The National Transgender Discrimination Survey was conducted by the National Gay and Lesbian Task Force and the National Center for Transgender Equality.

Injustice at Every Turn: A Report of the National Transgender Discrimination Survey

The importance of knowledge on tolerance of normal tissue organs to irradiation by radiation oncologists cannot be overemphasized. Unfortunately, current knowledge is less than adequate. With the increasing use of 3-D treatment planning and dose delivery, this issue, particularly volumetric information, will become even more critical. As a part of the NCI contract N01 CM-47316, a task force, chaired by the primary author, was formed and an extensive literature search was carried out to address this issue. In this issue. In this manuscript we present the updated information on tolerance of normal tissues of concern in the protocols of this contract, based on available data, with a special emphasis on partial volume effects. Due to a lack of precise and comprehensive data base, opinions and experience of the clinicians from four universities involved in the contract have also been contributory. Obviously, this is not and cannot be a comprehensive work, which is beyond the scope of this contract.

Tolerance of normal tissue to therapeutic irradiation.

Optimization of a treatment plan for radiation therapy will produce a plan with the highest probability for tumor control without exceeding an acceptable complication rate. To achieve this goal it is necessary to have a means to estimate probabilities of local control and normal tissue complication. In general, good treatment plans deliver a high uniform dose to the target volume and lower doses to the surrounding normal tissues. The tolerance dose values available for various normal tissues are usually assumed to apply to partial or full volumes of the tissue which have been uniformly irradiated. These values are the best guidelines for estimating complication probabilities in tissues that receive a uniform dose to a fraction of the tissue and no dose to the remainder. Dose-volume histograms are one means of evaluating the uniformity of the irradiation on the tissues. Frequently the normal tissues are not uniformly irradiated as is demonstrated by dose-volume histograms for different treatment plans. A recursive algorithm which uses these tolerance dose data has been written and can be applied to arbitrary dose-volume histograms to estimate the complication probability.

Complication Probability as Assessed from Dose-Volume Histograms

The national center for health statistics

To predict the likelihood of success of a therapeutic strategy, one must be able to assess the effects of the treatment upon both diseased and healthy tissues. This paper proposes a method for determining the probability that a healthy organ that receives a non-uniform distribution of X-irradiation, heat, chemotherapy, or other agent will escape complications. Starting with any given dose distribution, a dose-cumulative-volume histogram for the organ is generated. This is then reduced by an interpolation scheme (involving the volume-weighting of complication probabilities) to a slightly different histogram that corresponds to the same overall likelihood of complications, but which contains one less step. The procedure is repeated, one step at a time, until there remains a final, single-step histogram, for which the complication probability can be determined. The formalism makes use of a complication response function C(D, V) which, for the given treatment schedule, represents the probability of complications arising when the fraction V of the organ receives dose D and the rest of the organ gets none. Although the data required to generate this function are sparse at present, it should be possible to obtain the necessary information from in vivo and clinical studies. Volume effects are taken explicitly into account in two ways: the precise shape of the patient's histogram is employed in the calculation, and the complication response function is a function of the volume.

Optimization of radiation therapy, III: A method of assessing complication probabilities from dose-volume histograms.

Although it is well known that the tolerance of the liver to external beam irradiation depends on the volume of liver irradiated, few data exist which quantify this dependence Therefore, a review was carried out of our clinical trial for the treatment of intrahepatic malignancies in which the dose of radiation delivered depended on the volume of normal liver treated Three dimensional treatment planning using dose-volume histogram analysis of the normal liver was used for all patients Nine of the 79 patients treated developed clinical radiation hepatitis None of the patient related variables assessed were associated with radiation hepatitis All patients who developed radiation hepatitis received whole liver irradiation, as all or part of their treatment, which produced a mean dose greater than or equal to 37 Gy Dose volume histograms were used to calculate normal tissue complication probabilities based on parameters derived from the literature The risk of complication was greatly overestimated among patients receiving a high dose of radiation to part of the liver without whole liver treatment An estimation of model parameters based on the clinical results indicated a larger magnitude for the "volume effect parameter" than the literature estimate (n = 069 +/- 005 vs 032; p less than 0001) Computation of the normal tissue complication probabilities using the larger value of n produced a good description of the observed risk of radiation hepatitis These findings suggest that dose volume histogram analysis can be used to quantify the tolerance of the liver to radiation The predictive value of this parameterization of the normal tissue complication probability model will need to be tested with liver tolerance and dose volume histogram data from an independent clinical trial

John Lyman

Papers

Tolerance of normal tissue to therapeutic irradiation.

Complication Probability as Assessed from Dose-Volume Histograms

The national center for health statistics

Optimization of radiation therapy, III: A method of assessing complication probabilities from dose-volume histograms.

The use of 3-D dose volume analysis to predict radiation hepatitis.