Discrete classification of smokers by intention to quit is desirable in many public health and clinical settings.
Two methodological studies examine measurement properties of measures of discrete-time intention to quit smoking used in population-based tobacco surveillance surveys: an ecological comparison of rates of positive intention in relation to the form of measure used and a prospective analysis examining predictive validity of self-reported quit intentions using multiple possible points of dichotomization of an ordinal measure of intention to quit. The prospective analysis used a repeated measures design and follow-up to 1 year for 2,047 smokers in the Ontario Tobacco Survey cohort.
The estimated percent of smokers intending to quit was significantly higher using the Stages of Change intention measure, relative to another single question measure. Significant dose-response effects were found. The sooner one intended to quit the more likely one was to make an attempt or achieve at least 30 days abstinence in the next 6 months. Intending to quit in a month or later was not associated with cessation during follow-up among respondents without prior attempts. Examination of cutpoints revealed no value, which maximized both positive and negative prediction. Regardless of quit attempt history, greatest predictive validity was found where respondents stated that they had no intention at all.
Measures of intentions quit smoking in specific time periods and expressed as dichotomies have limited psychometric properties but utility in applied research. Our findings suggest a possible measurement effect warranting caution in comparisons across studies.
Managers of marine protected areas (MPAs) must often seek ways to allow for visitation while minimizing impacts to the resources they are intended to protect. Using shipboard observers, we quantified the "zone of disturbance" for Kittlitz's and marbled murrelets (Brachyramphus brevirostris and B. marmoratus) exposed to large cruise ships traveling through Glacier Bay National Park, one of the largest MPAs in North America. In the upper reaches of Glacier Bay, where Kittlitz's murrelets predominated, binary logistic regression models predicted that 61% of all murrelets within 850 m perpendicular distance of a cruise ship were disturbed (defined as flushing or diving), whereas in the lower reaches, where marbled murrelets predominated, this percentage increased to 72%. Using survival analysis, murrelets in both reaches were found to react at greater distances when ships approached indirectly, presumably because of the ship's larger profile, suggesting murrelets responded to visual rather than audio cues. No management-relevant covariates (e.g., ship velocity, route distance from shore) were found to be important predictors of disturbance, as distance from ship to murrelet accounted for > 90% of the explained variation in murrelet response. Utilizing previously published murrelet density estimates from Glacier Bay, and applying an average empirical disturbance probability (68%) out to 850 m from a cruise ship's typical route, we estimated that a minimum of 9.8-19.6% of all murrelets in Glacier Bay are disturbed per ship entry. Whether these disturbance levels are inconsistent with Park management objectives, which include conserving wildlife as well as providing opportunities for visitation, depends in large part on whether disturbance events caused by cruise ships have impacts on murrelet fitness, which remains uncertain.
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The objective of this study was to identify factors associated with a positive outcome of vocational rehabilitation, and to identify groups that have been successfully rehabilitated in a Swedish rural area. In this study vocational rehabilitation is defined as medical multidisciplinary, psychological, social and occupational activities aiming to re-establish, among sick or injured people with previous work history, their working capacity and prerequisites for returning to the labour market. The study was based on 732 people on registered long-term sick-leave who, in a rural area in northern Sweden during 1992-94, became objects for vocational rehabilitation. Bivariate and stepwise logistic regression analysis was used to identify factors associated with the outcome. By successful vocational rehabilitation is meant reporting well (no economical benefit) at all three time-points 6, 12 and 24 months after termination of rehabilitation, or lowered benefit levels. The results indicate that younger, male, employed persons, with an early start on rehabilitation, in a programme entailing education, and partly sick-listed before the start of this programme, had the greatest chance of successful rehabilitation. In contrast, older, female, unemployed people, with a delayed start on rehabilitation, without education, and fully sick-listed before the start, greatly risked being unsuccessful with vocational rehabilitation. The results indicate how to improve the rehabilitation process: several process-related factors shown to be connected with successful vocational rehabilitation include time before the start of rehabilitation, partial instead of full sickness benefit, and education programmes.
The aim of the study was to measure occupational exposure to electric and magnetic fields during various work tasks at switching and transforming stations of 110 kV (in some situations 20 kV), and analyze if the action values of European Union Directive 2004/40/EC or reference values of International Commission on Non-ionizing Radiation Protection (ICNIRP) were exceeded. The electric (n = 765) and magnetic (n = 203) fields were measured during various work tasks. The average values of all measurements were 3.6 kV m(-1) and 28.6 µT. The maximum value of electric fields was 15.5 kV m(-1) at task 'maintenance of operating device of circuit breaker from service platform'. In one special work task close to shunt reactor cables (20 kV), the highest magnetic field was 710 µT. In general, the measured magnetic fields were below the reference values of ICNIRP.
Undergraduate participants were tested in 144 pairs, with one member of each pair randomly assigned to a "witness" role and the other to an "investigator" role. Each witness viewed a target person on video under good or poor witnessing conditions and was then interviewed by an investigator, who administered a photo line up and rated his or her confidence in the witness. Witnesses also (separately) rated their own confidence. Investigators discriminated between accurate and inaccurate witnesses, but did so less well than witnesses' own confidence ratings and were biased toward accepting witnesses' decisions. Moreover, investigators' confidence made no unique contribution to the prediction of witnesses' accuracy. Witnesses' confidence and accuracy were affected in the same direction by witnessing conditions, and there was a substantial confidence-accuracy correlation when data were collapsed across witnessing conditions. Confidence can be strongly indicative of accuracy when witnessing conditions vary widely, and witnesses' confidence may be a better indicator than investigators'.
In this study, we examined the validity and clinical utility of the MMPI-2 (Butcher, Graham, Tellegen, Dahlstrom, & Kaemmer, 2001) Malingering Depression scale (Md) in relation to the MMPI-2 F scales (F, F(B), F(P)) to detect feigned depression. Overall, the F(B) scale and the F/F(P) scale combination were the best single predictors, although the Md scale did discriminate successfully cases of feigned depression from patients with bona fide depression. The Md scale added predictive capacity over the F scales, and the F(B) scale and the F/F(P) scale combination added predictive capacity over the Md scale; however, the actual increase in the number of cases predicted was minimal in each instance. In sum, although the Md scale is able to detect accurately feigned depression on the MMPI-2 (predictive validity), it does not confer a distinct advantage (incremental validity) over the existing standard validity scales-F, F(B), and F(P).
Surveys were conducted on regenerating stands of lodgepole pine to determine the relationship between root deformation and susceptibility to attack by the Warren root collar weevil, Hylobius warreni Wood. The total number of trees attacked by H. warreni did not differ between planted and natural trees. A matched case-control logistic regression suggested that root cross-sectional area was more important in predicting weevil attack for naturally regenerated trees than for planted trees, but weevils were associated with a larger reduction in height-to-diameter ratios for trees with planted root characteristics than for trees with natural root form. Neither the stability of attacked versus unattacked trees differed significantly and there was no significant interaction of weevil attack and tree type, but weevil-killed trees had different root characteristics than alive, attacked trees. Lateral distribution and root cross-sectional area were significant predictors of alive attacked trees versus weevil-killed trees, suggesting that trees with poor lateral spread or poor root cross-sectional area are more likely to die from weevil attack. We conclude that root deformation does not necessarily increase susceptibility to attack but may increase the likelihood of mortality. Thus, measures to facilitate good root form are needed when planting pine in areas with high risk of Warren root collar weevil attack.
The purpose of the current study was to examine the characteristics of those who report fulfillment of sexual desires as a result of internet use for sexual purposes and which sexually related online activities contribute to the fulfillment of sexual desires.
Data were collected through a questionnaire posted on Swedish-language websites in 2009. The sample comprised 1614 respondents who reported using the internet for sexual purposes, 62% women and 38% men.
The results showed that the majority of the respondents had their sexual desires fulfilled as a result of their sexually related activities on the internet; 21% to a great extent and 59% to a small extent, but 20% did not have their sexual desires fulfilled. Using a multinomial logistic regression analysis, respondents who had their sexual desires fulfilled to a small or great extent were each compared with those who did not have their sexual desires fulfilled at all. At the level of individual characteristics and sexual behaviours, those with no fulfillment of their sexual desires did not differ from those who had their sexual desires fulfilled, with the exceptions of age and masturbation. In comparison to fulfillment to a small extent, fulfillment of sexual desires to a great extent was predicted by a larger number of sexually related online activities that were based on interaction.
The findings suggest that the internet may contribute to fulfillment of sexual desires among a large internet population, irrespective of sex or sexual identity.
Wood mouse (Apodemus sylvaticus) populations are expected to show a peak in autumn in the year after a mast year of sessile oak (Quercus petraea), because stored acorns increase winter survival. In Aust-Agder, South Norway, only 16 of 34 mast years from 1939-2014 were followed by a year with a peak in the wood mouse population. For many of the remaining instances, there rather was a minor peak 2 or 3 years after the mast. In multiple logistic regression models, the probability of a wood mouse population peak after a mast year of sessile oak was positively related to a snow-corrected temperature index of the previous winter and negatively to a small rodent population index of the previous autumn. The present study thus supports the hypothesis that longer periods with snow-free ground and subzero temperatures negatively affect wood mouse winter survival. Because it may be difficult for wood mice to survive on a diet consisting of acorns alone, the negative relationship with the rodent population index of the previous year is most likely caused by an over-exploitation of necessary alternative food resources, such as other plant seeds and arthropods. Stored acorns not utilized during one winter are assumed to benefit wood mice in a succeeding winter, giving a delayed population peak relative to the mast year.