Irregular Shifts Research Articles

Kinematics of Eddy–Mean Flow Interaction in an Idealized Atmospheric Model

Abstract The authors analyze atmospheric variability simulated in a two-layer baroclinic β-channel quasigeostrophic model by combining Eulerian and feature-tracking analysis approaches. The leading mode of the model's low-frequency variability (LFV) is associated with the irregular shifts of the zonal-mean jet to the north and south of its climatological position accompanied by simultaneous intensification of the jet, while the deviations from the zonal-mean fields are dominated by propagating anomalies with wavenumbers 3–5. The model's variability is shown to stem from the life cycles of cyclones and anticyclones. In particular, synthetic streamfunction fields constructed by launching idealized composite-mean eddies along the actual full-model-simulated cyclone/anticyclone tracks reproduce nearly perfectly not only the dominant propagating waves, but also the jet-shifting LFV. The composite eddy tracks conditioned on the phase of the jet-shifting variability migrate north or south along with the zonal-mean jet. The synoptic-eddy life cycles in the states with poleward (equatorward) zonal-jet shift exhibit longer-than-climatological lifetimes; this is caused, arguably, by a barotropic feedback associated with preferred anticyclonic (cyclonic) wave breaking in these respective states. Lagged correlation and cross-spectrum analyses of zonal-mean jet position time series and the time series representing mean latitudinal location of the eddies at a given time demonstrate that jet latitude leads the storm-track latitude at low frequencies. This indicates that the LFV associated with the jet-shifting mode here is more dynamically involved than being a mere consequence of the random variations in the distribution of the synoptic systems.

Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers

OBJECTIVE: To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers.METHODS: A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support.RESULTS: Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively). The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05). Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively) than moderately-active day-shift workers (116 and 73.3 mmHg, respectively) (p < 0.05) as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively) (p = 0.01). Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively) than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05).CONCLUSIONS: Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical activity.

Leisure-time physical activity does not fully explain the higher body mass index in irregular-shift workers

To elucidate the influence of leisure-time physical activity on body mass index (BMI), appetite-related hormones, and sleep when working irregular shifts. A cross-sectional study was undertaken of 57 male truck drivers, 31 irregular-shift workers and 26 day-shift workers. Participants completed the International Physical Activity Questionnaire and were assessed for BMI. Subjects also provided a fasting blood sample for analysis of appetite-related hormones and wore an actigraphy device for seven consecutive days. Although leisure-time physical activity (LTPA) was generally low (<150 min/week) in both groups, the irregular-shift workers were more physically active than day-shift workers (99 ± 166 vs. 23 ± 76 min/week, p < 0.01). In spite of this, mean BMI of irregular-shift workers was 2 kg/m² greater than day-shift workers (28.4 ± 3.8 vs. 26.4 ± 3.6 kg/m², p = 0.04). Mean leptin concentration was 61 % higher in irregular-shift workers (5,205 ± 4,181 vs. 3,179 ± 2,413 pg/ml, p = 0.04). Among obese individuals, irregular-shift workers had higher leptin concentration (p < 0.01) and shorter sleep duration (p = 0.01) than obese day-shift workers. Elevated BMI was associated with high leptin and low ghrelin levels in this population of irregular-shift workers. No influence of LTPA on appetite-related hormones or sleep duration was found. We conclude that moderate LTPA is insufficient to attenuate the higher BMI associated with this type of irregular-shift work in truck drivers.

Introduction

Introduction Catherine Russell (bio) The Clock has been travelling to different museums and galleries around the world since it opened in London in 2010, challenging many conventions of film practice and spectatorship. Christian Marclay’s impressive, entertaining, and philosophical work engages tropes of found-footage film and video in a gallery installation to create a monumental form of digital cinema. It exists in the form of a hard drive and a tandem computer program that synchronizes the projection to the real time of the audience, such that the work itself literally tells time over a twenty-four hour period using close to a hundred thousand extracts from feature films. The installation also includes a specific seating arrangement of white sofas placed in a darkened room, evoking a home theater in a public space. The Clock has generated a great deal of discussion in the art world, the film world, and in the popular press. The articles presented here aim to situate the piece and the buzz it has generated in a critical perspective, contextualizing it within museum culture, moving image history, and theoretical paradigms of spectatorship, temporality, and the archive. A common theme in the critical discourse around The Clock is the lament, even among those who are critical, that they didn’t think of it first. It seems so easy and so obvious; and in fact, as Eli Horwatt points out, it’s possible that another filmmaker—Christophe Girardet—did think of it first.1 As digital tools have made found-footage filmmaking into a practice accessible and available to all computer-users, the mash-up and the video essay have become popular forms of experimental media. From the YouTube fan tributes to favorite stars, to Oscar night homages, to sophisticated video essays in web journals such as Frames and Vectors, ripping clips from films for reassembly is now standard practice, even if [End Page 163] it often remains legally circumspect. That Marclay was able to borrow fragments from thousands of films under fair use guidelines within the rarified auspices of the art world tends to ruffle feathers, even while it contributes to the awesome statement that the work has made. Although one critic has suggested that “this whole assembly could have been made by a computer program,”2 in fact it was a huge expenditure of manual labour. Marclay’s six assistants collected the material over a course of three years, while Marclay edited the segments together. The soundtrack, for which Marclay collaborated with Quentin Chiappetta, is a tour de force of mixing, remastering, and counterpoint. Whatever one may think of its blockbuster appeal, The Clock is a technically and formally accomplished work of picture and sound editing.3 The montage is at many points highly expressive, while at others subtly invisible, and Marclay fully exploits devices of suspense, comedy, and contrast. On these levels, the piece sustains a rhythmic pace that varies, constantly, with irregular timings and shifts in mood and tempo. There is no question that it has a seductive appeal, due in part to the extensive use of suspense effects and the proliferation of movie stars. Many descriptions of The Clock suggest that a clock face is seen in every shot, but in fact Marclay has used a variety of techniques for telling time. The time of day may be mentioned verbally, along with periods of time that may or may not be accurately measured by the compilation, as in: “I’ll wait for just five minutes!” He also includes scenes in which characters discuss time more abstractly, as in multiple clips from The Time Machine (George Pal, US, 1960), and people asking “what time is it?” or people looking at their watch with no specific time mentioned, or clocks on which the time is slightly illegible. Marclay weaves series of scenes from a given film into the collage, not all of which feature timepieces. The Clock, in fact, includes many shots with no mention of time whatsoever, and no clock or watch-face either. These sequences are important means by which the work incorporates another sense of time besides clock time, which we might nevertheless say is produced by clock time by being outside...

Conflict Between Work and Family Roles and Satisfaction among Nurses in Different Shift Systems in Croatia: a Questionnaire Survey

The objective of this study was to examine the perception of conflict between work and family roles and job, family, and life satisfaction among nurses in Croatia. One hundred and twenty-nine nurses (married mothers) working in hospitals in Zadar, Šibenik, and Split were divided in four groups according to their worktime schedule. The participants completed a survey, which included a set of sociodemographic-type questions, questions about the level and allocation of family responsibilities between spouses, and scales measuring the perceived negative effects of worktime, psychological demands of the work, work-family conflict, and semantic differential scales for measuring the affective and cognitive-evaluative component of job, family, and life satisfaction. This was the first study in Croatia to deal with work-family conflict among nurses or workers with different shift systems.The results of this study indicate that nurses working morning shifts only experienced less conflict between work and family than other groups of nurses, who worked the morning, afternoon, and the night shift. The cognitive-evaluative component of job satisfaction was the highest among morning shift nurses and the lowest in nurses who worked 12-hour shifts, while the affective component of life satisfaction was the lowest in nurses working irregular and backward rotated shifts. These results confirm that shiftwork makes the work-family role conflict even worse. They also support the view that the type of shift rotation matters.

Possible evidence of the resonant influence of solar forcing on the climate system

An assumption of the existence of natural climatic oscillations driven by solar activity enables an explanation of phase differences between variations in solar activity and rainfall level in Fortaleza, Brazil. Decadal and interdecadal variations in rainfall level can be reproduced using a forced oscillation equation with a driving force term that describes the variation in the sunspot number and with the assumption of the existence of 31.7-year interdecadal and 12.96-year decadal natural climatic oscillations. This equation satisfactorily reproduces the periodicity with a length of approximately 22yr in the interdecadal rainfall variation before and up to the middle of the past century as well as the subsequent phase inversion, period and amplitude increase in the variation that followed the corresponding increases in the interdecadal sunspot number variation. The equation accurately reproduces the irregular phase shifts between decadal variations in rainfall level and in sunspot number over the entire 160yr of recorded observations.

Morning Cortisol Levels and Perceived Stress in Irregular Shift Workers Compared with Regular Daytime Workers

The 24/7 work environment and irregular shifts may markedly enhance the psychological pressure of media work. Changes in the hypothalamic-pituitary-adrenal axis reflect adaptation to stress. We analysed the correlation between subjective stress, sleep, salivary cortisol, and melatonin hormones among Finnish media workers with regular daytime work (RDW) and with irregular shift work (ISW) while controlling confounders. From 874 employees with regular daytime work or with irregular shift work, 70 employees from both groups were randomly selected. The final number of employees with a complete salivary cortisol profile was 66 in the RDW group and 65 in the ISW group. Five saliva samples were gathered from each subject before and during a working day. The salivary cortisol level of the sample taken 60 minutes after awakening (T1) was compared to the salivary cortisol level taken immediately after awakening (T0, T1/T0 ratio). The ratio was higher in the ISW group than in RDW group. Irregular shift work (P < 0.001), severe stress (P < 0.05), and less sleep (P < 0.05) were independently associated with an augmented cortisol response after awakening. A stressful work environment and irregular shift work enhance cortisol excretion after waking. In the long run, this may become detrimental to health.

Irregular working times and metabolic disorders among truck drivers: a review

A number of studies to better understand the complex physiological mechanism involved in regulating body weight have been conducted. More specifically, the hormones related to appetite, leptin and ghrelin, and their association to obesity have been a focus of investigation. Circadian patterns of these hormones are a new target of research. The behaviour of these hormones in individuals subject to atypical working times such as shiftwork remains unclear. Shiftwork is characterized by changes in biological rhythms and cumulative circadian phase changes, being associated with high rates of obesity and metabolic syndrome. Truck drivers, who work irregular shifts, frequently present a high prevalence of obesity, which might be associated with work-related factors and/or lifestyle. In this context, the aim of this paper was to discuss the relationship of body mass index, appetite-related hormones and sleep characteristics in truck drivers who work irregular shifts compared with day workers.

Antecedents, Work-Related Consequences, and Buffers of Job Burnout Among Indian Software Developers

This study examines the antecedents, consequences, and buffers of job burnout among software developers using job demands resources theory. Data were collected from 372 software developers in India using questionnaires. Results reveal that software developers experiencing more role ambiguity, role conflict, schedule pressure, irregular shifts, group noncooperation, psychological contract violation, and work–family conflict are at a greater risk of job burnout. The most important antecedent of job burnout was found to be work–family conflict. Job burnout increased job performance but decreased organizational commitment and interpersonal relationships. Subjective well-being and practicing yoga and meditation were inversely related to burnout-linked job performance. Subjective well-being, social support, and practicing yoga and meditation were also found to decrease the adverse association of job burnout with organizational commitment and interpersonal relationships. In the context of work-related consequences, job burnout had the biggest adverse association with organizational commitment, and practicing yoga and meditation was found to be the most influential buffer to counter the adverse consequences of job burnout.

When Does Stress End? Evidence of a Prolonged Stress Reaction in Shiftworking Truck Drivers

This study aimed to analyze individual cortisol levels in relation to work conditions, sleep, and health parameters among truck drivers working day shifts (n = 21) compared to those working irregular shifts (n = 21). A total of 42 male truck drivers (39.8 ± 6.2 yrs) completed questionnaires about sociodemographics, job content, work environment, health, and lifestyle. Rest-activity profiles were measured using actigraphy, and cardiovascular blood parameters were collected. Salivary cortisol samples were obtained: (i) at waking time, (ii) 30 min after waking, and (iii) at bedtime, during both one workday and one day off from work. Irregular-shift workers, compared to day-shift workers, showed significantly higher waist-hip ratio, very-low-density lipoprotein (VLDL) cholesterol, tiredness after work, years working as a driver, truck vibration, and less job demand (p < .05). High cortisol levels in irregular-shift workers were correlated with certain stressors, such as short sleep duration and low job satisfaction, and to metabolic parameters, such as total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), VLDL, and triglycerides. Day-shift workers had higher cortisol levels collected 30 min after waking (p = .03) and a higher cortisol awakening response (CAR; p = .02) during workdays compared to off days. Irregular-shift workers had higher cortisol levels on their off days compared to day-shift workers (p = .03). In conclusion, for the day-shift workers, a higher cortisol response was observed on workdays compared to off days. Although no direct comparisons could be made between groups for work days, on off days the irregular-shift workers had higher cortisol levels compared to day-shift workers, suggesting a prolonged stress response in the irregular-shift group. In addition, cortisol levels were correlated with stressors and metabolic parameters. Future studies are warranted to investigate further stress responses in the context of irregular work hours. (Author correspondence: crmoreno@usp.br)

Half Job—Half Training? Management Perceptions of Part-time Employee Training in the Hospitality Industry

The author used a qualitative research approach in this study to investigate why hospitality managers provide fewer training opportunities to part-time employees in comparison to their full-time colleagues. Data was collected through in-depth, one-on-one interviews with 22 hotel and restaurant owners/managers in South Wales, United Kingdom. The results showed seven main obstacles for training part-time employees: cost of training and return on investment; time of training; the working of irregular shifts; working background; low enthusiasm of part-time employees; high turnover of part-time employees; lack of resources, knowledge, and suitable training provision. These obstacles are all interlinked and they are all associated with managers’ perception of part-time employees and their assumptions that part-time employees are not interested in training and development.

Zn(II), Cd(II) and Hg(I) complexes of cinnamic acid: FT-IR, FT-Raman, 1H and 13C NMR studies

The effect of zinc, cadmium(II) and mercury(I) ions on the electronic structure of cinnamic acid (phenylacrylic acid) was studied. In this research many miscellaneous analytical methods, which complement one another, were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance ( 1H, 13C NMR) and quantum mechanical calculations. The spectroscopic studies provide some knowledge on the distribution of the electronic charge in molecule, the delocalization energy of π-electrons and the reactivity of metal complexes. In the series of Zn(II) → Cd(II) → Hg(I) cinnamates: (1) systematic shifts of several bands in the experimental and theoretical IR and Raman spectra and (2) regular chemical shifts for protons 1H and 13C nuclei were observed.

Low-Income Mothers' Nighttime and Weekend Work: Daily Associations With Child Behavior, Mother-Child Interactions, and Mood

This study investigated low-income mothers' daily nighttime and weekend work and family outcomes. Sixty-one mothers of preschool-aged children reported daily on work hours, mood, mother-child interaction, and child behavior for two weeks (N = 724 person-days). Although nighttime and weekend work are both schedules, results showed adverse associations of working nighttime hours on family outcomes-more negative mood and mother-child interactions; less positive child behavior-but no relationship between weekend work and family outcomes. Key Words: low-income families, parent-child relationships, work and families, working mothers. In the last half century, the number of women participating in the labor force in the United States has increased dramatically, with particular increases among low-income women (Blank, 2002). At the same time, the nature of work in the United States has evolved. Service and sales sectors have expanded, and the economy increasingly operates around the clock, amplifying demand for workers outside the traditional 9-to-5 workday (Presser, 2003). It is now common for individuals to work schedules - in the evening, nights, or on weekends - leading to concerns about the effects of work scheduling on families and children. Nonstandard work is more common among lower-income individuals (Presser), and so children in low-income families are more likely to be affected by their parents' work schedules. Research on the effects of work schedules on both workers and their families has generally found that work schedules have negative effects, particularly in studies of mixed- and higher-income families (Han, 2005, 2006; Han & Waldfogel, 2007; Strazdins, Clements, Korda, Broom, & D'Souza, 2006; Strazdins, Korda, Lim, Broom, & D'Souza, 2004). Studies focused on low-wage workers, however, have produced mixed results (Han, 2008; Hsueh & Yoshikawa, 2007; Joshi & Bogen, 2007; Phillips, 2002), and additional information is still needed about how mothers' work schedules affect low-income families. Prior research has commonly compared parents categorized as working or schedules, on the basis of a typical work week. That design has three limitations: unobserved selection into different schedules may bias results; standard and nonstandard categories may mask withinperson variability in work schedules; and, in most studies, the nonstandard category includes both nights and weekends, although their consequences may differ. This study addressed a number of limitations in the literature on work during schedules. First, it focused on an understudied group, low-wage workers with preschool-age children. Second, it collected daily reports from low-income working mothers over a period of two weeks regarding work schedules, maternal mood, mother-child interaction, and child behavior. Rather than comparing workers who have been grouped into static work schedule categories, the design of this study allowed for the examination of within-family variability in work schedules. Thus, the results presented here more rigorously address the selection problem that has plagued studies of work schedules. Finally, this study considered the effects of different types of schedules - nighttime work and weekend work - separately. NONSTANDARD WORK SCHEDULES IN LOW-INCOME FAMILIES Although researchers' exact definitions of work schedules differ, most agree that work includes evenings, nights, or weekends, and on rotating or irregular shifts (Presser, 2003). Standard schedules are defined as fixed daytime hours, Monday to Friday. Work during schedules is increasingly common. Across income levels, 29% of working mothers worked schedules in 2004 (McMenamin, 2007). That rate is even higher in the services and hospitality industries, which employ high numbers of low- wage workers. …

Relationship between work–family conflict and a sense of coherence among Japanese registered nurses

Work-family conflict (WFC) refers to the conflict that arises between a person's work and family life. Previous studies have reported workload, job demands, and irregular working shifts as related to the WFC among nurses and have clarified that WFC is a predictor of job satisfaction, morale, and turnover intention. Very few studies have investigated WFC among Japanese nurses and no study has taken into consideration the sense of coherence (SOC) that helps nurses to cope with stress. The present study aimed to determine the relationship between WFC and SOC and to clarify how WFC and a SOC influence the mental and physical health of nurses in order to suggest ways of establishing work environments that enable nurses to achieve a balance between their work and family life. A self-report questionnaire survey of 388 Japanese female nurses was conducted. The data from 138 nurses who were a mother and/or wife were analyzed. Work-family conflict was significantly related to the SOC. It had a larger impact on the physical and mental health of nurses than their work and family characteristics. The SOC also had a major influence on the physical and mental health of nurses, while having a buffering effect on WFC with respect to depression. Our findings underscore the importance of taking organizational steps to create work environments that contribute to an enhanced SOC in order to reduce the WFC among nurses.

THE IMMPLEMENTATION LEVEL OF WHEAT GROWERS OF THE GRADUATES IN RELATION TO RECOMMENDATIONS IN SAHL EL -TINA IN SINAI PENINSULA

The research aimed to: identify the degree of implementation levelof wheat growers of the graduates in relation to wheat recommendationsdetermine the corelation relationship between the studied variables and theimmplementation level, recognize the information sources of the graduates,and finally know the the problems faced them.The research was conduced in Sahl El–Tina in Sinai Peninsula on thewheat growers of the graduates. Three villages were selected according tothe cultivated wheat area village No. 2, 4 and 7. Date were collected throughpersonal questionnaire on sample of 164 respondent. Percentages, statisticalaverages and correlation coefficient wers used to analyze data.Findings indicated that 15.2% of the graduates were in the Low Levelof the immplementation of wheat recommendations compared with 25% inthe average level and 59.8% in the high level of immplementatien.Data analysis reported a significant relationship between each of : age,scientifical qualification, cultivated area of wheat, attitudes towardsagricultural innovations, leadership degree, working years in wheatcultivation.Findings also reported that there is no significat relationship betweensize of landholding and family size whith the independent variable.The most important sources of information were neighbors, merchantof seeds and pesticides, xtentions workers, researchers in Desert ResearchCenter, and tv programs. Findings also reported some problemes facilnggraduates to which were as follows: high salinity of soil, irregular shifts ofirrigation, monavialability of seed on time, high prices of fertilizer,herbicides, the transfer of the crop, and the difficulty in obtaining loans, andfinally the problem of high wages for agricultural labor.

Occupational health hazards resulting from elevated work rate situations.

Some occupational health hazards resulting from an elevated rate of work due to recent mechanization and automatization are discussed on the basis of results of health examinations. A rapid increase of a cervicobrachial disorder among young cash register and packing machine operators has been observed. Switching to the use of electronic cash registers has been shown to have only limited efficacy due to increased operation speed, and high-speed complex finger and hand movements of packer operators have also proven to be as hazardous as key-board operations. The high incidence of low-back pain, in particular gradually developing pain, among workers in electric power supply work has been suggested to be the result of quick and intensified work to meet increasing supply demand. Likewise, the workload of electric locomotive and bullet train drivers has increased in accordance with increased train speeds, and has been shown to have had significant effects on their health particularly in regards to neural strain, intra-cab environment such as air pressure change, vibration, and noise, and rotation on irregular shifts. New steps seem required therefore to meet the new health problems arising from a combination of modern technological changes and elevated working speeds.

Physiological Response Of USAR-workers During Training In Extreme Hot Conditions

Urban Search And Rescue (USAR) teams are often deployed in areas where the ambient conditions can be classified as 'extreme'. USAR operations often take several days in which team members work in irregular work shifts. The extreme conditions combined with the irregular work shifts involve high physical demands. Little is known about the physiological requirements of search-and-rescue tasks under extreme conditions over a prolonged period of time. PURPOSE: To evaluate the physiological responses of Dutch USAR-workers during a 4-day training period in the desert near Dubai (UAE). METHODS: The training period was divided in three parts: a 2 day adaptation period in the heat, 4 consecutive days of USAR training and a 2 day recovery period. During the adaptation period the activities as ordered by the training staff were observed by the research team. During the 4 day training period, 8 experienced USAR-workers (42.3±7.2 yr; BMI 27.0±3.7) were monitored. Core temperature (Tcore) and heart rate (HR) was measured with the EquivitalTM-system (Hidalgo Ltd., Cambridge UK). The percentage heart rate reserve (%HRR) as derived from HR was used as measure for the relative physical workload. Environmental conditions were measured and logged with a mobile weather station (QuestTemp 36, Oconomowoc, WI, USA) to calculate the Wet Bulb Globe Temperature (WBGT). RESULTS: During the adaptation period the rescue workers were ordered to stay outdoors as much as possible and be physically active in the heat. This resulted in a 10-15% prevalence of symptoms of heat related problems (headache, nausea, etc.). During the 4 day training period a mean WBGT-value of 27.4±3.6°C (range: 23.7-34.5°C) was measured. A mean core temperature during rescue activities of 38.0±0.3°C was measured. Individual values for Tcore exceeded 39.5°C. The mean workload was 'light to moderate' (between 20-40%HRR), but during some of the activities peak values of 80%HRR were calculated. On the final day of the training period one of the subjects was hospitalized due to severe heat illness. CONCLUSION: It is concluded that the training of the Dutch USAR-team took place under extreme environmental conditions. Although mean physiological responses were not extremely high, individual values pointed out that the USAR-workers were exposed to extreme high risks.

Alignment of capillary electrophoresis–mass spectrometry datasets using accurate mass information

Capillary electrophoresis-mass spectrometry (CE-MS) is a powerful technique for the analysis of small soluble compounds in biological fluids. A major drawback of CE is the poor migration time reproducibility, which makes it difficult to combine data from different experiments and correctly assign compounds. A number of alignment algorithms have been developed but not all of them can cope with large and irregular time shifts between CE-MS runs. Here we present a genetic algorithm designed for alignment of CE-MS data using accurate mass information. The utility of the algorithm was demonstrated on real data, and the results were compared with one of the existing packages. The new algorithm showed a significant reduction of elution time variation in the aligned datasets. The importance of mass accuracy for the performance of the algorithm was also demonstrated by comparing alignments of datasets from a standard time-of-flight (TOF) instrument with those from the new ultrahigh resolution TOF maXis (Bruker Daltonics).

Parental work schedules and adolescent depression

Using a large contemporary United States data set, the National Longitudinal Survey of Youth-Child Supplement (NLSY-CS), this paper examines the relationship between parental work schedules and adolescent depression at age 13 or 14, paying particular attention to the mechanisms that may explain this relationship. Analysis based on structural equation modelling showed that increased work at night by mothers was significantly associated with a lower quality of home environment and fewer meals together, and this mediator was significantly linked to increased risks for adolescent depression. In addition, evening work by fathers was significantly associated with lower paternal closeness and this mediator was significantly associated with increases in adolescent depression. In contrast, irregular shifts by both mothers and fathers increased the likelihood of mothers knowing where the child was and this relationship in turn reduced adolescent depression. Implications and avenues for future research are discussed.

Shiftwork impacts and adaptation among health care workers

Shiftwork among health care workers impacts upon the safety and health of both employees and patients. To characterize shiftwork-related attitudes, behaviours, symptoms and coping strategies among health care workers, two validated questionnaires (the Standard Shiftwork Index and the Pressure Management Indicator) were used to identify factors predicting shiftwork adaptation. Participants (n = 376, response rate 25%) were grouped according to their work schedule (days, permanent evenings, rotating days plus evenings, permanent nights or relief and combined shifts). Indicators of lifestyle, work organization, sleep disruption, health and pressure management among workers on irregular shifts were compared with participants on day shifts, after adjustment for gender, age and marital status. Principal components analysis and ordinal logistic regression were used among irregular shiftworkers to identify factors predicting schedule adaptation. Night and relief/combined shiftworkers reported a greater ability to accommodate irregular schedules and disrupted sleep, but were also more likely to report work-related impacts than day workers. Permanent night workers generally reported poorer health, more absenteeism and less job satisfaction than day workers. Factors associated with optimal work performance or schedule contentment among shiftworkers included adequate sleep, evening circadian preference, increased age and organizational satisfaction. Reduced work performance or schedule discontent was associated with sleep/wake difficulties and poor health. This study confirmed previous research and identified factors that can be targeted for the development of more effective shiftwork adaptation programmes in a health care setting (sleep timing and duration, exercise and optimal health and organizational satisfaction).