Lifetime Hours Research Articles

Hobbies with solvent exposure and risk of non-Hodgkin lymphoma

Occupational exposure to solvents has been reported to increase non-Hodgkin lymphoma (NHL) risk in some, but not all, studies. In a population-based case-control study, we examined whether participation in selected hobbies involving solvent exposure increases NHL risk. We identified NHL cases diagnosed at ages 20-74 years between 1998 and 2000 in Iowa or metropolitan Los Angeles, Detroit, and Seattle. Controls were selected using random digit dialing or Medicare files. Computer-assisted personal interviews (551 cases, 462 controls) elicited data on model building, painting/silkscreening/artwork, furniture refinishing, and woodworking/home carpentry. Hobby participation (68% of cases, 69% of controls) was not associated with NHL risk (OR = 0.9, 95% CI = 0.7-1.2). Compared to people with none of the hobbies evaluated, those who built models had significantly lower risk (OR = 0.7, CI = 0.5-1.0), but risk did not vary with the number of years or lifetime hours. Risk estimates for the other hobbies were generally less than one, but the associations were not significant and there were no notable patterns with duration of exposure. Use of oil-based, acrylic, or water-based paints; paint strippers; polyurethane; or varnishes was not associated with NHL risk. We conclude that participation in hobbies involving exposure to organic solvents is unlikely to increase NHL risk.

Hobbies with Solvent Exposure and Risk of Non-Hodgkin Lymphoma

Occupational exposure to solvents has been reported to increase non-Hodgkin lymphoma (NHL) risk in some, but not all, studies. In a population-based case-control study, we examined whether participation in selected hobbies involving solvent exposure increases NHL risk. We identified NHL cases diagnosed at ages 20-74 years between 1998 and 2000 in Iowa or metropolitan Los Angeles, Detroit, and Seattle. Controls were selected using random digit dialing or Medicare files. Computer-assisted personal interviews (551 cases, 462 controls) elicited data on model building, painting/silkscreening/artwork, furniture refinishing, and woodworking/home carpentry. Hobby participation (68% of cases, 69% of controls) was not associated with NHL risk (OR = 0.9, 95% CI = 0.7-1.2). Compared to people with none of the hobbies evaluated, those who built models had significantly lower risk (OR = 0.7, CI = 0.5-1.0), but risk did not vary with the number of years or lifetime hours. Risk estimates for the other hobbies were generally less than one, but the associations were not significant and there were no notable patterns with duration of exposure. Use of oil-based, acrylic, or water-based paints; paint strippers; polyurethane; or varnishes was not associated with NHL risk. We conclude that participation in hobbies involving exposure to organic solvents is unlikely to increase NHL risk.

An undesirable cardiac impact of vigorous sport practice: Lone atrial fibrillation

Atrial fibrillation (AF), characterized by rapid chaotic electrical impulses of 300–600 per minute circulating within the atria and resulting in dysfunctional atrial activity and an irregular heart rate, is the most common sustained arrhythmia encountered in clinical practice. Lone AF is defined as AF in the absence of structural heart disease or other identifiable causes as hyperthyroidism or alcohol abuse. Regular physical activity have been well known to be associated with reduced cardiovascular morbidity [1,2]. However, some investigators have reported a significant association between excessive sport practice in competitive athletes and in recreational athletes and the occurrence of lone AF [3–5] during the last years. In a recently published paper, Elosua et al. [6] have evaluated the relation between sport practice and the prevalence of lone AF in men. In an agematched case-control study, 51 patients with lone AF and 109 control subjects were included. They have used a questionnaire to assess former and current sport practice and the number of lifetime hours of sport practice. The combination of current and prolonged lifetime sport practice (lifetime sport practice greater than 1500 h) have been shown to be associated with higher risk of lone AF. Similarly, Mont et al. [3] have investigated the association between long-term sport practice and lone AF in men. They have shown that a high proportion of men with lone AF (63%) had practised sport regularly for many years. This proportion is significantly higher than the proportion of males younger than 65 years who practise sport regularly in the general pop-

A search for massive magnetic monopoles at the Baksan Underground Scintillation Telescope (BUST)

The experiment has been performed for both fast ( β ⩾ 0.4 ) and slow ( 2 × 10 −4 ⩽ β ⩽ 10 −1 ) monopoles. In velocity range β ⩾ 0.4 , we made use of the cascade trigger (large energy deposition in facility), time-of-flight method was used for 10 −4 ⩽ β ⩽ 10 −1 range. No candidate for monopole was obtained during 35400 hours and 127630 hours of live time respectively.

Sport practice and the risk of lone atrial fibrillation: A case–control study

Background Lone atrial fibrillation (LAF) is characterized by the presence of atrial fibrillation in the absence of structural heart disease or other identifiable cause of arrhythmia. In a recent study, we reported sport practice to be more frequent in LAF patients than in the general population. The aim of the study was to determine the association between sport practice and the prevalence of LAF in men. Methods An age-matched case–control study was designed. Cases were identified from consecutive patients who attended an outpatient clinic; 51 men with LAF were included, 20 of them with vagal characteristics. Controls were selected from the general population ( n = 109). A questionnaire to assess former and current sport practice and the number of lifetime hours of sport practice was administered. Conditional logistic regression was used for statistical analysis. Results The proportion of patients with LAF who reported current sport practice (31%) was higher than that observed in controls (14%). In the logistic regression, current practice of sport was associated with a higher prevalence of LAF (OR = 3.13; 95% CI: 1.39–7.05). The practice of more than 1500 lifetime hours of sport appears to be the threshold for the observed association. Current practice of sport with a lifetime practice greater than 1500 h was associated with LAF (OR = 2.87; 95% CI: 1.20–6.91). Conclusion In men, the combination of current and prolonged lifetime sport practice is associated with higher risk of LAF.

Photovoltage Enhancement: Analysis of Polaron Formation and Charge Transport at the Junctions of Organic Polythiophene and Inorganic Semiconductors

We report the charge transport properties at the junction of organic polythiophene (PT) and inorganic semiconductors. Using a Kelvin probe and surface photovoltage spectroscopy, we have found that excitation of inorganic semiconductor band gaps led to hole migration across the inorganic-organic interface (IOI) and subsequently creation of polaron states in PT polymer chains. Of particular interesting is that these polaron states yield photovoltage responses initially at 675 nm, and eventually over the entire region of the visible spectrum. Because of their long lifetime (hours to days), the density of these polaron states increases with the exposure time of photoexcitations of the inorganic semiconductor until saturation is reached. The net result is that photovoltage is enhanced over the visible spectrum through charge transfer of polaronlike states in PT to inorganic semiconductors. Sunlight can induce obvious photovoltage enhancement at these IOI junctions, which show potential promise in the future application of large area photovoltaic technology.

Experimental limit on the cosmic diffuse ultrahigh energy neutrino flux.

We report results from 120 h of live time with the Goldstone lunar ultrahigh energy neutrino experiment (GLUE). The experiment searches for < or = 10 ns microwave pulses from the lunar regolith, appearing in coincidence at two large radio telescopes separated by 22 km and linked by optical fiber. Such pulses would arise from subsurface electromagnetic cascades induced by interactions of > or = 100 EeV (1 EeV = 10(18) eV neutrinos in the lunar regolith. No candidates are yet seen, and the implied limits constrain several current models for ultrahigh energy neutrino fluxes.

Handheld cellular telephones and risk of acoustic neuroma.

The hypothesis that intracranial energy deposition from handheld cellular telephones causes acoustic neuroma was tested in an epidemiologic study of 90 patients and 86 control subjects. The relative risk was 0.9 (p = 0.07) and did not vary significantly by the frequency, duration, and lifetime hours of use. In patients who used cellular telephones, the tumor occurred more often on the contralateral than ipsilateral side of the head. Further efforts should focus on potentially longer induction periods.

Epidemiology of digital epiluminescence microscopy features of acquired melanocytic naevi.

This study addressed the independent association of past and recent sun exposure indicators and other host factors with the prevalence of major digital epiluminescence microscopy (D-ELM) features such as the pigment network (PN), brown globules (BGs), and pigment dots (PDs) in acquired melanocytic naevi. In a consecutive series of 189 patients (median age 28 years; range 10-73 years) with one or more naevi as diagnosed on D-ELM, we evaluated 35 solitary lesions and one naevus randomly selected from each of the 154 patients with multiple lesions. D-ELM images were classified for the presence or absence of PN, BGs and PDs on two blind readings. Data analysis was based on multiple logistic regression. Patient age was positively associated with PN and inversely associated with BGs. The probability of PN increased with more than 110 days since last exposure to the sun, whereas a rapid decrease for BGs and PDs was observed after approximately 1 month. PDs were significantly more likely among lesions with 6-10 h/day of recent exposure. Sex, total lifetime hours of exposure, sunbed use, skin type and colour of hair exerted no effect. In conclusion, major D-ELM features appeared to differ in their relationship with sun exposure indicators.

New Directions in National Economic Accounting

The national income and product accounts (NIPA) are the most important measures of overall economic activity for a nation. Much as a satellite in space can survey the weather across an entire continent, so can the GDP give an overall picture of the state of the economy. Nevertheless, since their inception, there have been concerns that the accounts are incomplete and misleading because they omit vast continents of nonmarket activity such as unpaid work, the value of leisure time, investment in human capital, and most recently, the environment. The threshold question is: why should we devote scarce intellectual resources to studying nonmarket sectors? The basic insight behind nonmarket accounts is that economic and social welfare does not stop at the market’s border, but extends to many nonmarket activities. Three particular areas are worth emphasizing. One important reason why we need better measures of nonmarket activity is because we spend increasingly fewer of our lifetime hours in market activities. A second and more speculative reason concerns the growing importance (or at least the great importance) of nonmarket assets or mispriced market assets such as the environment and technology. A third point is that current measures of national saving and investment are highly defective. The examples later in this paper address each of these issues. Many of these issues were reviewed in a recent report on augmented accounting by the National Academy of Sciences (see Nordhaus and Edward Kokkelenberg, 1999).

Symptoms of hand-arm vibration syndrome in gas distribution operatives.

OBJECTIVES: To survey the prevalence and severity of hand-arm vibration syndrome symptoms (HAVS), and to estimate past and current exposure to hand held vibrating tools in a sample of gas...

Self-reported Noise Exposures Among Ohio Cash Grain Farmers

As part of the NIOSH-funded Ohio Farm Family Health and Hazard Survey (OFFHHS), self-reported noise exposure data were collected from more than 1,700 Principal Operators (POs) of cash grain farms. Information on exposure to occupational and non-occupational noise sources was obtained by means of a statewide mixed-mode survey.With respect to occupational sources, nearly all survey respondents reported a history of cabless tractor operation, approximately 80% had operated a chain saw, and approximately 70% had operated a combine. About 1/3 respondents reported current employment in a noisy job in addition to farming, while nearly 20% reported a history of non-agricultural noisy employment. The most frequently reported nonoccupational sources of noise exposure were hunting (51.5% of respondents), motorcycle riding (21.2%), and target shooting (20.5%). Self-reported equipmentspecific data on total years of operation or use, days of operation or use per year, and mean hours of operation or use per day were used to estimate lifetime hours of exposure to noisy activities/tasks. Of the more than 61 million cumulative lifetime hours of exposure reported by the 1,700+ respondents, more than half was accounted for by operation of cabless tractors. In addition, 2/3 respondents reported they never wear hearing protection when they operate or are around noisy farm equipment. Attempts to identify factors associated with use of hearing protection revealed that although the prevalence of usage varied by age and education, use was poor across all subgroups examined, suggesting that agricultural workers of all ages and levels of education would benefit from interventions designed to reduce the incidence of noiseinduced hearing loss.

Metalorganic chemical vapor epitaxy and doping of ZnMgSSe heterostructures for blue emitting devices

Blue-green semiconductor laser diodes operating at room temperature are still the domain of wide bandgap II–VI compound semiconductors. CW operation at room temperature and hours of lifetime were reported. However, the conductivity control, defect generation and the ohmic contacts still need improvement. Therefore we focused our work on the MOVPE growth and the optimization of ZnMgSSe/ZnSSe/ZnSe heterostructures as well as on nitrogen doping of ZnSe. To verify the layer quality characterization was carried out by X-ray diffraction, electron probe microanalysis, electrical measurements and photoluminescence. ZnMgSSe/ZnSSe/ZnSe and ZnSSeZnSe quantum wells and superlattices were grown to investigate structural as well as interface properties. Electron beam and optical pumping was used to clarify the laser mechanism and to clarify the suitability of a MOVPE process to grow laser quality material. The electrical compensation of ZnSe doped with nitrogen is still controversially discussed whereas high n-type doping with chlorine was reproducible achieved. ZnSe: N doped at different growth conditions (IIVI ratio, growth temperature, nitrogen supply) using N2 excited in a plasma source or by the use of nitrogen containing precursors was investigated to study the compensation mechanisms.

Working less and living longer: Long-term trends in working time and time budgets

Analyses of time series data beginning in the mid-nineteenth century in the industrialized nations, especially the United Kingdom, show that on average people are working significantly less while living longer. Although the average career length has remained around 40 years, the total life hours worked shrank for an average British worker from 124,000 hours in 1856 to 69,000 in 1981. The fraction of disposable lifetime hours spent working declined from 50% to 20%. Meanwhile the female share of career years doubled to 30%. If the long-term trends continue at their historic rates, the work week might average 27 hours by the year 2050. The secular trend away from the formalized work contract to other socially obligatory activities and free time implies numerous challenges for human societies.

Cigarette Smoking: Risk Factor for Premature Facial Wrinkling

To determine if cigarette smoking is a risk factor for the development of premature facial wrinkling. Cross-sectional study. Smoking cessation clinic and community. Convenience sample of 132 adult smokers and non-smokers in 1988. A questionnaire was administered to quantify cigarette smoking and to obtain information about possibly confounding factors such as skin pigmentation, sun exposure, age, and sex. Wrinkling was assessed using photographs of the temple region, and a severity score based on predetermined criteria was assigned. A logistic regression model, which controlled for confounding variables, was developed to assess the risk for premature wrinkling in response to pack-years of smoking. The prevalence of premature wrinkling was independently associated with sun exposure and pack-years of smoking. After controlling for age, sex, and sun exposure, premature wrinkling increased with increased pack-years of smoking. Heavy cigarette smokers (greater than 50 pack-years) were 4.7 times more likely to be wrinkled than nonsmokers (95% CI, 1.0 to 22.6; P value for trend = 0.05). Sun exposure of more than 50,000 lifetime hours also increased the risk of being excessively wrinkled 3.1-fold (CI, 1.2 to 7.1). When excessive sun exposure and cigarette smoking occurred together, the risk for developing excessive wrinkling was multiplicative (prevalence ratio of 12.0; CI, 1.5 to 530). Cigarette smoking is an independent risk factor for the development of premature wrinkling.

15–100 keV variability in her X-1 observed by HEAO-1

During the 18 month mission lifetime of HEAO-1, Her X-1 was observed for 183 days of scanning by the UCSD/MIT Hard X-Ray and Low Energy Gamma-Ray Experiment, producing 14 hours of on-source livetime over five 35 day cycles. Included in this time are 13 pointed observations made at various 35 day phases, accounting for 29 hours of livetime on-source. Four complete main-ons were observed to have varying durations. Two complete short-ons and two partial short-ons were also observed. We present here results on pulse shape variations with 35 day phase as well as with energy, spectral variations with pulse phase, and pulse fractions with energy and phase. These results may indicate that the the 35d intensity profile is not due to a simple blocking mechanism at the distance of the accretion disk, and that repeatable changes in the accretion geometry near the pulse formation region may be occurring with 35d phase.

Leisure and Life-Styles of the Elderly: Outline of a Research Programme

The leisure of the elderly has not played an important role in gerontological research in Germany up to now. Yet interest in it has increased along with the discussions about the reduction of life-time working hours that are taking place in all the Western industrialised countries. But the little research on this topic, if any, is often of a quantitative kind; it is primarily limited to the general analysis of leisure activities and does not sufficiently differentiate between social groups within the elderly. Thus in this area of gerontology much ground has to be made up in the way of research, which, if carried out properly, may also contribute to further theoretical developments in gerontology. This means mainly that more qualitative research should be conducted. The question is then what kind of approach should be adopted in order to compensate for the deficiencies of gerontology in the field of leisure and, in addition, to bring out the main points for further development. This paper is concerned with such an approach and its application to an empirical study.

Lifetime analyses of error-control coded semiconductor RAM systems

The paper is concerned with developing quantitative results on the lifetime of coded random-access semiconductor memory systems. Although individual RAM chips are highly reliable, when large numbers of chips are combined to form a large memory system, the reliability may not be sufficiently high for the given application. In this case, error-correction coding is used to improve the reliability and hence the lifetime of the system. Formulas are developed which will enable the system designer to calculate the improvement in lifetime (over an uncoded system) for any particular coding scheme and size of memory. This will enable the designer to see if a particular memory system gives the required reliability, in terms of hours of lifetime, for the particular application. In addition, the designer will be able to calculate the percentage of identical systems that will, on average, last a given length of time.

On the Carbon, Oxygen, and Neon Burning Stages.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the Carbon, Oxygen, and Neon Burning Stages. Reeves, Hubert Abstract The conditions under which subsequent nuclear burning stages would follow the hydrogen and helium stages in a stellar core are investigated. Taking as a lower limit to the total energy output of a star its neutrino luminosity, regions of the density temperature plane are determined in which a core can stop its contraction by burning one of these fuels. Upper limits to the lifetime of these stages can then be calculated. Estimating the photon luminosity to lie in the neighborhood of 10 to 102 ergs per gram per second, the carbon burning stage would take place at temperatures of about 0.60 BK for densities of 10 g/cm2 or more, the lifetime being some 30 000 years or so. Only for densities below 3 X l0 g/cm2 is the burning postponed till later temperature. At - 10 it would take place at T-0.9 with lifetime of a few years. For the next stages the photon luminosity can be entirely disregarded in view of the very large neutrino luminosity. For densities around 10 the 0 and fe~ stages would be roughly simultaneous at T- 1.3 to 1.5 and lifetime I to 10 years. At lower densities (o 106) the Ne burning would markedly precede the oxygen burning with T from 1.5 to 1.7, lifetime hours compared with oxygen, T 1.5 to 2.0, lifetime da ~s. Publication: The Astronomical Journal Pub Date: March 1962 DOI: 10.1086/108825 Bibcode: 1962AJ.....67Q.280R full text sources ADS |