88 research outputs found
Potato
Soil erosion is a serious agricultural problem. Most of the available literature
on the subject concerns nonirrigated cropland where natural precipitation
and snowmelt water produce the forces needed to erode soil and transport
sediment. Most of the water providing those forces for erosion on irrigated
land is that applied by humans to supply water to growing crops. The purpose
of this chapter is to provide a review of irrigation-induced soil erosion
and to supply some insight into its hazards and control
Effects of total sleep deprivation on performance in a manual spacecraft docking task
Sleep deprivation and circadian rhythm disruptions are highly prevalent in shift workers, and also among astronauts. Resulting sleepiness can reduce cognitive performance, lead to catastrophic occupational events, and jeopardize space missions. We investigated whether 24âhours of total sleep deprivation would affect performance not only in the Psychomotor Vigilance Task (PVT), but also in a complex operational task, i.e. simulated manual spacecraft docking. Sixty-two healthy participants completed the manual docking simulation 6df and the PVT once after a night of total sleep deprivation and once after eight hours of scheduled sleep in a counterbalanced order. We assessed the impact of sleep deprivation on docking as well as PVT performance and investigated if sustained attention is an essential component of operational performance after sleep loss. The results showed that docking accuracy decreased significantly after sleep deprivation in comparison to the control condition, but only at difficult task levels. PVT performance deteriorated under sleep deprivation. Participants with larger impairments in PVT response speed after sleep deprivation also showed larger impairments in docking accuracy. In conclusion, sleep deprivation led to impaired 6df performance, which was partly explained by impairments in sustained attention. Elevated motivation levels due to the novelty and attractiveness of the task may have helped participants to compensate for the effects of sleepiness at easier task levels. Continued testing of manual docking skills could be a useful tool both to detect sleep loss-related impairments and assess astronautsâ readiness for duty during long-duration missions
Impact of Common Diabetes Risk Variant in MTNR1B
The risk of type 2 diabetes (T2D) is increased by abnormalities in sleep quantity and quality, circadian alignment, and melatonin regulation. A common genetic variant in a receptor for the circadian-regulated hormone melatonin (MTNR1B) is associated with increased fasting blood glucose and risk of T2D, but whether sleep or circadian disruption mediates this risk is unknown. We aimed to test if MTNR1B diabetes risk variant rs10830963 associates with measures of sleep or circadian physiology in intensive in-laboratory protocols (n = 58â96) or cross-sectional studies with sleep quantity and quality and timing measures from self-report (n = 4,307â10,332), actigraphy (n = 1,513), or polysomnography (n = 3,021). In the in-laboratory studies, we found a significant association with a substantially longer duration of elevated melatonin levels (41 min) and delayed circadian phase of dim-light melatonin offset (1.37 h), partially mediated through delayed offset of melatonin synthesis. Furthermore, increased T2D risk in MTNR1B risk allele carriers was more pronounced in early risers versus late risers as determined by 7 days of actigraphy. Our results provide the surprising insight that the MTNR1B risk allele influences dynamics of melatonin secretion, generating a novel hypothesis that the MTNR1B risk allele may extend the duration of endogenous melatonin production later into the morning and that early waking may magnify the diabetes risk conferred by the risk allele
Many Labs 5:Testing pre-data collection peer review as an intervention to increase replicability
Replication studies in psychological science sometimes fail to reproduce prior findings. If these studies use methods that are unfaithful to the original study or ineffective in eliciting the phenomenon of interest, then a failure to replicate may be a failure of the protocol rather than a challenge to the original finding. Formal pre-data-collection peer review by experts may address shortcomings and increase replicability rates. We selected 10 replication studies from the Reproducibility Project: Psychology (RP:P; Open Science Collaboration, 2015) for which the original authors had expressed concerns about the replication designs before data collection; only one of these studies had yielded a statistically significant effect (p < .05). Commenters suggested that lack of adherence to expert review and low-powered tests were the reasons that most of these RP:P studies failed to replicate the original effects. We revised the replication protocols and received formal peer review prior to conducting new replication studies. We administered the RP:P and revised protocols in multiple laboratories (median number of laboratories per original study = 6.5, range = 3?9; median total sample = 1,279.5, range = 276?3,512) for high-powered tests of each original finding with both protocols. Overall, following the preregistered analysis plan, we found that the revised protocols produced effect sizes similar to those of the RP:P protocols (?r = .002 or .014, depending on analytic approach). The median effect size for the revised protocols (r = .05) was similar to that of the RP:P protocols (r = .04) and the original RP:P replications (r = .11), and smaller than that of the original studies (r = .37). Analysis of the cumulative evidence across the original studies and the corresponding three replication attempts provided very precise estimates of the 10 tested effects and indicated that their effect sizes (median r = .07, range = .00?.15) were 78% smaller, on average, than the original effect sizes (median r = .37, range = .19?.50)
Trading Accuracy for Speed in Selective Attention Tasks during Sleep Deprivation
Objective
Selective attention is a critical cognitive function in tasks that require careful monitoring of visual information. An increasing amount of night work on jobs that meet such requirements motivates the study of the effects of sleep deprivation (SD) on selective attention. Monitoring tasks in occupational settings can be operationalized for study in the laboratory by visual search tasks, in which the subject has to identify rare target items among distractor items. Visual search under SD leads to a decrease of overall response speed and accuracy. However, an increase of response speed per item with increasing number of items was also found under SD. This might indicate an unfavorable speed-accuracy trade-off: decision speed per item increases, while accuracy decreases in turn. Eye gaze tracking may provide additional indications for the duration of individual decisions during the search process.
Methods
We recorded gaze behavior during two standard visual search tasks to explore if SD leads to faster and sloppier decisions per item (shorter fixation durations). Visual search performance (response time and sensitivity dâ) in the conjunction (CST) and spatial configuration (SST) search task and the associated gaze behavior were tested in two groups of subjects. While sleep deprived participants (N=24, age: 25 ± 5 SD; 12 women) were kept awake during a 24 hour period, participants of a control group (N=24, age: 26 ± 4 SD; 10 women) were allowed to sleep (TIB: 8 hours).
Results
We found an increase of response time under SD compared to the control group (CST: p = 0.019, MSD= 128 ms ± 220 SD , MC= 1 ms ± 169 SD; SST: p < 0.001, MSD= 65 ms ± 755 SD , MC=- 45 ms ± 604 SD) and a decrease in sensitivity dâ (CST: p = 0.03, MSD= -0.14 ± 0.65 SD , MC= 0.01 ± 0.58 SD; SST: p < 0.001, MSD=-0.43 ± 0.82 SD , MC= 0.10 ± 0.64 SD) . For gaze behavior, we found indications of a cognitive slowing in slower saccade velocities for the SD group compared to the control group (CST: p < 0.001, MSD= -38.8 °/s ± 42.4 SD , MC= -5.1 °/s ± 33.8 SD; SST: p < 0.001, MSD= -29.0 °/s ± 32.4 SD , MC= -2.8 °/s ± 23.7 SD) but not in terms of longer fixation durations. On the contrary, fixation durations decreased in the SD group relative to the control group (CST: p = 0.018, MSD= -16.1 ms ± 30.3 SD , MC= -6.2 ms ± 25.1 SD; SST: p = 0.008, MSD= -11.0 ms ± 23.4 SD , MC= -2.2 ms ± 19.7 SD). Moreover, the change in fixation duration was positively correlated with the change in task accuracy (CST: Ï = 0.29, p = 0.048; SST: Ï = 0.33, p = 0.022), suggesting that subjects that showed the strongest decrease in fixation duration exhibited also the strongest decrease in search accuracy. Further analysis showed that the general decrease of fixation duration was mainly associated with a steep increase of the frequency of very brief fixation durations, so called âexpress fixationsâ with durations shorter than 120 ms.
Conclusion
The decrease in fixation duration under SD is further evidence for a shifted speed-accuracy trade-off as indicated by earlier search studies. SD seemingly leads to an increase of decision speed at the cost of reduced accuracy. Consequently, SD not only results in overall cognitive slowing but also in an impairment of adequate resource allocation in selective attention, potentially due to the absence of prefrontal inhibitory control
Sleep and anxiety: From mechanisms to interventions
Anxiety is the most common mental health problem worldwide. Epidemiological studies show that sleep disturbances, particularly insomnia, affect -50% of individuals with anxiety, and that insufficient sleep can instigate or further exacerbate it. This review outlines brain mechanisms underlying sleep and anxiety, by addressing recent human functional/structural imaging studies on brain networks underlying the anxiogenic impact of sleep loss, and the beneficial effect of sleep on these brain networks. We discuss recent developments from human molecular imaging studies that highlight the role of specific brain neurotransmitter mechanisms, such as the adenosinergic receptor system, on anxiety, arousal, and sleep. This review further discusses frontline sleep interventions aimed at enhancing sleep in individuals experiencing anxiety, such as nonbenzodiazepines/antidepressants, lifestyle and sleep interventions and cognitive behavioral therapy for insomnia. Notwithstanding therapeutic success, up to -30% of individuals with anxiety can be nonresponsive to frontline treatments. Thus, we address novel noninvasive brain stimulation techniques that can enhance electroencephalographic slow waves, and might help alleviate sleep and anxiety symptoms. Collectively, these findings contribute to an emerging biological framework that elucidates the interrelationship between sleep and anxiety, and highlight the prospect of slow wave sleep as a potential therapeutic target for reducing anxiety. (c) 2021 Elsevier Ltd. All rights reserved
Die BeeintrÀchtigung der Schlafarchitektur durch nÀchtlichen FluglÀrm bei Grundschulkindern
Fragestellung: Ungestörter Schlaf gilt als eine bedeutsame Voraussetzung fĂŒr eine gesunde körperliche und geistige Entwicklung von Kindern. FluglĂ€rm kann Ănderungen in der Schlafarchitektur sowie Aufwachreaktionen hervorrufen. Da insbesondere Grundschulkinder zu Zeiten schlafen, zu denen das Flugverkehrsaufkommen und die resultierende LĂ€rmbelastung noch relativ hoch sind, gilt ihr Schlaf als vulnerabel gegenĂŒber FluglĂ€rmwirkungen. Studien zu den Akutwirkungen von nĂ€chtlichem FluglĂ€rm auf den kindlichen Schlaf existierten bisher jedoch nicht. Die Studie untersuchte daher den Einfluss nĂ€chtlichen FluglĂ€rms auf die Schlafarchitektur im Grundschulalter.
Methoden: In einer Feldstudie wurden 51 gesunde und normalhörende Kinder (8-10 Jahre, 23 MĂ€dchen) zu Hause wĂ€hrend vier aufeinanderfolgender NĂ€chte schlafphysiologisch untersucht. Die Messung der FluglĂ€rmbelastung erfolgte kontinuierlich wĂ€hrend jeder Nacht im Kinderschlafzimmer am Ohr des schlafenden Kindes. Die Studie fand im Umfeld des Flughafens Köln/Bonn statt, an dem durchgehend Nachtflugbetrieb vorherrscht. In einer Mixed ANOVA wurden zentrale Schlafparameter (die Einschlaflatenz, die Dauer von Tiefschlaf, REM-Schlaf, Wachphasen sowie die Schlafeffizienz) in zwei LĂ€rmbelastungsgruppen verglichen. Es wurde unterschieden zwischen höherer und niedrigerer Belastung, definiert durch die Anzahl an ĂberflĂŒgen mit einem Innenmaximalpegel von mindestens 30 dB(A) (Median-Split aller 144 auswertbaren NĂ€chte bei 37,5 ĂberflĂŒgen pro Nacht).
Ergebnisse: Kinder, die in NĂ€chten mit einer höheren FluglĂ€rmbelastung schliefen, verbrachten weniger Zeit im Tiefschlaf (p=.010), lagen wĂ€hrend der Schlafperiodenzeit lĂ€nger wach (p=.016) und zeigten mehr lĂ€rmassoziierte Wechsel in S1 oder wach (p<.001) als Kinder, die bei niedrigerer LĂ€rmbelastung schliefen. AuĂerdem war die Schlafeffizienz in Tendenz (p=.054) niedriger, die Einschlaflatenz dagegen tendenziell lĂ€nger (p=.077) in der höher lĂ€rmbelasteten Gruppe. Die im REM-Schlaf verbrachte Zeit unterschied sich zwischen den beiden Gruppen nicht (p=.682).
Schlussfolgerung: NĂ€chtlicher FluglĂ€rm wirkte sich auf die Schlafarchitektur von Grundschulkindern aus. Verglichen mit den BeeintrĂ€chtigungen durch schlafbezogene Atemstörungen, die in Studien bei Kindern beobachtet wurden, waren die LĂ€rmeffekte etwas geringer. Welche gesundheitlichen Auswirkungen chronische, verkehrslĂ€rmbedingte Ănderungen in der Schlafarchitektur, insbesondere die andauernde VerkĂŒrzung des Tiefschlafes, haben können, sollte im Fokus zukĂŒnftiger Untersuchungen stehen
KurzzeitbelÀstigung und subjektive Schlafstörungen durch FluglÀrm bei Grundschulkindern: Ergebnisse der Studie MIDAS
Fragestellung: Der kindliche Schlaf gilt gegenĂŒber nĂ€chtlichen VerkehrslĂ€rmwirkungen als gefĂ€hrdet, da Kinder mehr Schlaf benötigen und abends frĂŒh zu Bett gehen, wenn Verkehrsströme und LĂ€rmbelastungen noch relativ hoch sind. LĂ€rmbedingte Schlafstörungen können psychologische SekundĂ€rreaktionen zur Folge haben, z.B. eine erhöhte MĂŒdigkeit und BelĂ€stigung am Tag. Studien zu den Akutwirkungen von nĂ€chtlichem FluglĂ€rm auf den Schlaf und die resultierenden psychologischen Effekte bei Kindern gab es bisher nicht.
Methoden: In einer Feldstudie am Flughafen Köln/Bonn wurden 51 gesunde und normalhörende Kinder (8-10 Jahre, 23 MĂ€dchen) zu Hause wĂ€hrend vier aufeinanderfolgender NĂ€chte untersucht. Die Kinder bewerteten am Morgen nach dem Aufstehen jede vergangene Nacht rĂŒckblickend in Bezug auf ihre KurzzeitbelĂ€stigung durch FluglĂ€rm. ZusĂ€tzlich wurde die subjektive MĂŒdigkeit und SchlafqualitĂ€t erfragt. Persönliche und situative Moderatoren der KurzzeitbelĂ€stigung (z.B. LĂ€rmempfindlichkeit, Bewertung des Flugverkehrs) wurden im Rahmen eines Interviews erfasst. Die Messung der LĂ€rmbelastung erfolgte kontinuierlich wĂ€hrend jeder Nacht im Kinderschlafzimmer. Die FluglĂ€rmbelastung wurde operationalisiert durch die Anzahl der FluglĂ€rmereignisse (FLE) mit einem Maximalpegel â„ 30 dB(A).
Ergebnisse: Eine gemischte ANOVA ergab, dass bezĂŒglich der subjektiven Beurteilung der SchlafqualitĂ€t und der MĂŒdigkeit kein Unterschied zu erkennen war zwischen geringer vs. höher fluglĂ€rmbelasteten NĂ€chten (Median-Split bei 37 FLE, p=0,694 bzw. p=0,269). FĂŒr die KurzzeitbelĂ€stigung fand sich ebenfalls kein Effekt des FluglĂ€rms (p=0,396).
Ein logistisches Regressionsmodell zeigte, dass die Wahrscheinlichkeit wĂ€hrend der Nacht durch FluglĂ€rm belĂ€stigt zu sein, bei Kindern ĂŒberwiegend von persönlichen Eigenschaften abhĂ€ngig war. Sie war höher bei Kindern, die sich selbst als lĂ€rmempfindlich einschĂ€tzten, Flugzeuge als gefĂ€hrlich betrachteten und die bei geistigen Aufgaben lĂ€rmreduzierende MaĂnahmen ergriffen (z.B. Fenster schlieĂen). Sie stand in keinem statistisch signifikanten Zusammenhang mit der tatsĂ€chlichen FluglĂ€rmbelastung in der Nacht, (p=0,050).
Schlussfolgerung: Anders als bei Erwachsenen hat die nĂ€chtliche FluglĂ€rmbelastung kaum Einfluss auf die kurzzeitige BelĂ€stigung und die selbst eingeschĂ€tzte SchlafqualitĂ€t und MĂŒdigkeit bei Kindern. Persönliche Faktoren wie die individuelle LĂ€rmempfindlichkeit der Kinder sind hingegen maĂgebliche Faktoren der Bewertungen
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