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- Körning-Ljungberg, Jessica, et al.
(författare)
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Cognitive after-effects of vibration and noise exposure and the role of subjective noise sensitivity
- 2007
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Ingår i: Journal of Occupational Health. - : Wiley. - 1341-9145 .- 1348-9585. ; 49:2, s. 111-116
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effects on attention performance after exposure to noise and whole-body vibration in relation to subjective noise sensitivity. Sixteen high and 16 low sensitivity male students, as determined by the Weinstein Noise Sensitivity Questionnaire, participated in a within-subjects experiment. Noise and vibration stimuli similar to those usually occurring in forestry vehicles were presented either individually, combined or not at all in four separate sessions lasting approximately 44 min. After exposure, participants completed an attention task and made subjective ratings of alertness. No main effect of noise sensitivity was observed in MANOVA, thus the data was pooled with the data from a pilot study using the exact same procedure without using a noise sensitivity inclusion criterion. The combined data revealed performance degradation in the attention task after exposure to vibration, regardless as to whether it was presented alone or in combination with noise. Increased ratings of alertness after vibration exposure and decreased ratings of alertness after noise exposure were also found. Neither synergistic nor antagonistic effects were observed from the combined noise and vibration exposure.
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- Lindros, Ola, et al.
(författare)
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Accidents in family forestry´s firewood production
- 2008
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Ingår i: Accident Analysis and Prevention. - : Elsevier. - 0001-4575 .- 1879-2057. ; 40, s. 877-886
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Tidskriftsartikel (refereegranskat)abstract
- Firewood is commonly used around the world, but little is known about the work involved in its production and associated accidents. The objectives were to identify relationships between accidents and time exposure, workers’ age and sex, equipment used and work activities in family forestry’s firewood production. Data from a postal survey in Northern Sweden were compared to a database of injuries in the same region. Most accidents occurred to 50–69 year old men, who also worked most hours. No significant differences in sex and age were found between expected and recorded accident frequencies when calculated from total work hours; however, when calculated using numbers of active persons significant differences were found for both age and sex. Frequency of accidents per unit worked time was higher for machine involving activities than for other activities. Accidents that occurred when using wedge splitter machines were responsible for most of this overrepresentation. Fingers were the most commonly injured body parts. Mean accident rate for the equipment used was 87 accidents per million work hours, and the rate was highest for wedge splitters (122 accidents per million work hours). Exposure to elevated risks due to violation of safety procedures is discussed, as well as possible preventative measures.
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| 8. |
- Ljungberg, Jessica K., 1971-, et al.
(författare)
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Stress, subjective experience and cognitive performance during exposure to noise an vibration
- 2007
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Ingår i: Journal of Environmental Psychology. - : Elsevier. - 0272-4944 .- 1522-9610. ; 27:1, s. 44-54
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effects of noise and whole-body vibration on saliva cortisol levels and subjectively rated difficulty and stress while performing cognitive tasks. In the first experiment, 24 men completed a logical reasoning task and a short-term memory task while, on separate occasions, being exposed to noise, vibration, combined stimuli, and control conditions. The environmental stimuli were designed to simulate the exposure from a forestry vehicle. The main finding was that participants made significantly higher ratings of stress when the noise stimulus was present, either alone or in combination with vibration. There were, however, some indications that noise sensitivity might moderate both subjective and objective measures such as higher ratings of stress and elevated cortisol levels in high noise sensitive participants. A second experiment was conducted where noise sensitivity was used as an inclusion criterion. A low sensitive and a high sensitive group were created, each containing 16 participants. The results of the second experiment, found only marginal effects of noise sensitivity and no effects at all on performance or cortisol. Increased ratings of stress and difficulty were found whenever either environmental stressor was present, whether by itself or in combination. The same result was seen even when pooling the data from both experiments. The main conclusion of the study is that relatively short exposures to noise and vibration typical of those levels that are found in industrial vehicles do not significantly affect performance in cognitive tasks nor saliva cortisol levels even if work in these environments can be experienced as more difficult or stressful.
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| 9. |
- Neely, Gregory, et al.
(författare)
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Self-reported incidents, accidents, and use of protective gear among small-scale forestry workers in Sweden
- 2006
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 44:8, s. 723-732
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Tidskriftsartikel (refereegranskat)abstract
- Self-reported data were collected from 156 self-employed small-scale forestry workers regarding their work, including use of safety gear and number and type of incidents and accidents. About 40% of the respondents reported that during the previous 24 months they had some kind of work-related accident where an injury occurred, and/or experienced in incident, a close call that could have resulted in an injury. Of those injured or involved in an accident, 50% reported that at the time of the accident or incident they were not fully using their safety gear. Sixty-seven percent of the accident victims reported seeking medical attention for their injuries. No significant relationships were found between production level, age, use of safety gear or sensation seeking tendencies and the reports of accidents and incidents. Accidents and incidents were most likely to occur during felling, thinning and transportation activities and were usually caused by unforeseen interactions with falling trees/branches or equipment. Compared to earlier surveys of Swedish small-scale forestry workers, consistent use of all required safety gear was down by 10% to 50%. Protective pants and gloves were the items least likely to be used while ear, eye and foot protection were most likely to be used. The results indicate that better planning during felling processes may be the key to reducing the number of accidents for this population.
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- Phillipson, Mia, et al.
(författare)
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Vav1 is essential for mechanotactic crawling and migration of neutrophils out of the inflamed microvasculature
- 2009
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 182:11, s. 6870-6878
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Tidskriftsartikel (refereegranskat)abstract
- Mac-1-dependent crawling is a new step in the leukocyte recruitment cascade that follows LFA-1-dependent adhesion and precedes emigration. Neutrophil adhesion via LFA-1 has been shown to induce cytoskeletal reorganization through Vav1-dependent signaling, and the current study investigates the role of Vav1 in the leukocyte recruitment process in vivo with particular attention to the events immediately downstream of LFA-1-dependent adhesion. Intravital and spinning-disk-confocal microscopy was used to investigate intravascular crawling in relation to endothelial junctions in vivo in wild-type and Vav1(-/-) mice. Adherent wild-type neutrophils almost immediately began crawling perpendicular to blood flow via Mac-1 until they reached an endothelial junction where they often changed direction. This pattern of perpendicular, mechanotactic crawling was recapitulated in vitro when shear was applied. In sharp contrast, the movement of Vav1(-/-) neutrophils was always in the direction of flow and appeared more passive as if the cells were dragged in the direction of flow in vivo and in vitro. More than 80% of Vav1(-/-) neutrophils moved independent of Mac-1 and could be detached with LFA-1 Abs. An inability to release the uropod was frequently noted for Vav1(-/-) neutrophils, leading to greatly elongated tails. The Vav1(-/-) neutrophils failed to stop or follow junctions and ultimately detached, leading to fewer emigrated neutrophils. The Vav1(-/-) phenotype resulted in fewer neutrophils recruited in a relevant model of infectious peritonitis. Clearly, Vav1 is critical for the complex interplay between LFA-1 and Mac-1 that underlies the programmed intravascular crawling of neutrophils.
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| 12. |
- van den Berg, Johannes, et al.
(författare)
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Electroencephalography and subjective ratings of sleep deprivation
- 2005
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Ingår i: Sleep Medicine. - : Elsevier BV. - 1389-9457 .- 1878-5506. ; 6:3, s. 231-240
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Tidskriftsartikel (refereegranskat)abstract
- Sleep-related vehicle accidents account for many injuries and fatalities each year on monotonous motorways and roads. To effectively prevent such incidents requires greater knowledge of the mechanisms and development of the effects of sleep deprivation. Ten volunteers participated in a laboratory study aimed to analyze the way changes in wakefulness were described in terms of EEG changes and subjective ratings. Patients and methods For each subject, the study consisted of four testing sessions that varied in length on different days: one session each of 60, 90, and 120 min when sleep-deprived, and one session of 120 min when rested. Changes in wakefulness were analyzed using electroencephalographic recordings and ratings on two different scales, the Karolinska Sleepiness Scale (KSS) and the Category-Ratio Scale (CR-10). Results The results indicate quite conclusively that significant changes in the perception of sleepiness occur during the first 60–90 min of sedentary, monotonous work. Beyond this time period, subjective and physiological changes remained constant throughout the rest of the 120-min period. Conclusion In general, the subjective rating scales highly and significantly correlated with theta activity in both tired and rested states and with alpha activity in the rested state. Similar results were seen using both subjective rating scales.
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| 13. |
- van den Berg, Johannes, et al.
(författare)
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Heart rate variability during sedentary work and sleep in normal and sleep-deprived states
- 2005
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 25:1, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of using heart rate variability (HRV) as an indicator of sleepiness was investigated by analysing heart rate (HR) activity and electroencephalography (EEG) recordings from 10 individuals who performed a monotonous attention task for 120 min in both sleep-deprived and rested states. In both conditions, measurements were collected during 60 min of sleep immediately following a 120 min of non-sleep (awake phase). Although HR decreased significantly in both the rested and the sleep-deprived states during the awake phase, HR significantly changed sooner when subjects were sleep-deprived than when they were rested. No significant changes in HRV were found during the awake phase; however, HRV correlated significantly with alpha and theta power densities when rested but not when sleep-deprived. During the sleep phase, the total HRV and very low and low frequency HRV components significantly decreased approximately 40 min after sleeping in the sleep-deprived condition. These HRV components were also significantly and negatively correlated with delta power densities. HRV does not seem to be a viable indicator of sleepiness; however, HRV may be useful for determining sleep stages.
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| 14. |
- van den Berg, Johannes, 1962-
(författare)
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Indicators and predictors of sleepiness
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sleep is a basic need as important as physical fitness and good nutrition. Without enough sleep, we will create a sleep debt and experience sleepiness. Sleepiness can be defined as the inability to stay awake, a condition that has become a health problem in our 24-hour-7-day-a-week society. Estimates suggest that up to one-third of the population suffers from excessive sleepiness. Among other interactions, sleepiness affects our performance, increasing the risk of being involved in accidents. A considerable portion of work related accidents and injuries are related to sleepiness resulting in large costs for the individuals and society. Professional drivers are one example of workers who are at risk of sleepiness related accidents. Up to 40% of heavy truck accidents could be related to sleepiness. A better knowledge about reliable indicators and predictors of sleepiness is important in preventing sleepiness related accidents.This thesis investigates both objective and subjective indicators of sleepiness, how these relate to each other, and how their pattern changes over time. The indicators investigated were electroencephalography, heart rate variability, simple reaction time, head movement, and subjective ratings of sleepiness (Study I-IV). In Study V, a questionnaire study was conducted with professional drivers in northern Sweden. This study mainly deals with predictors of sleepiness. When subjects were sleep deprived both objective and subjective ratings indicated a rapid increase in sleepiness during the first hour of the test followed by a levelling off. This change in pattern was evident for all the indicators except heart rate and heart rate variability. On the other hand, HRV was correlated with the increase of EEG parameters during the post-test sleep period. The changes in pattern of the indicators included in the thesis are analysed in the perspective of temporal patterns and relationships. Of the tested indicators, a subjective rating of sleepiness with CR-10 was considered to be the most reliable indicator of sleepiness. Of the investigated predictors of sleepiness, prior sleep habits were found to be strongly associated to sleepiness and the sleepiness related symptoms while driving. The influences of driving conditions and individual characteristics on sleepiness while driving were lower. A multidisciplinary approach when investigating and implementing indicators and predictors of sleepiness is important. In addition to their actual relations to the development of sleepiness, factors such as technical and practical limitations, work, and individual and situational needs must be taken into account.
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| 15. |
- van den Berg, Johannes, et al.
(författare)
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Performance on a simple reaction time task while sleep deprived
- 2006
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Ingår i: Perceptual and Motor Skills. - 0031-5125 .- 1558-688X. ; 102:2, s. 589-599
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Tidskriftsartikel (refereegranskat)abstract
- Divergent results have been reported on the effect of a night's sleep loss on performance of a single monotonous task. The present experiment examined the effect that partial sleep deprivation had on 10 participants' performance on a simple reaction time task requiring low responding for 120 min. compared to performance on the same task when well rested. Participants missed significantly more signals and had slower reaction times when sleep deprived. Reaction times increased with time when participants were both sleep deprived and rested, but the number of misses did not significantly change over time. Reaction time was significantly correlated with subjective ratings of sleepiness and heart rate in both conditions. EEG and heart-rate variability measures did not correlate significantly with reaction time. Misses correlated significantly with subjective ratings and heart rate but only in the rested condition.
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