981 research outputs found

    Aerobic And Anaerobic Changes In Collegiate Male Runners Across A Cross-Country Season

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    The purpose of this study was to assess the physiological characteristics of trained NCAA Division III male runners across a competitive season of cross-country. Eight male distance runners (age 20.6±1.4 y) were administered a battery of aerobic and anaerobic laboratory tests at the beginning and end of an 8-10 week racing season. Aerobic testing included maximal oxygen uptake (VO2max), running economy (RE), ventilatory threshold (VT) and the onset of blood lactate accumulation (OBLA). Anaerobic testing consisted of the vertical jump (VJ) and the Wingate test. Final testing revealed anaerobic Wingate peak power significantly declined (11.8±1.1 to 10.7±1.0 W·kg-1) (P = 0.006), while no significant changes were seen in VJ or any aerobic parameters (P \u3e 0.05). These results indicate that a competitive cross-country season of training and racing diminished anaerobic peak power and failed to elicit quantifiable aerobic adaptations in previously trained collegiate distance runners

    Spurengasmessungen in der Tropopausenregion zur Charakterisierung von StratosphÀren-TroposphÀren-Austauschprozessen

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    Die Chemie und der Strahlungshaushalt der ErdatmosphĂ€re werden durch die nur in relativ geringen Konzentrationen vorhandenen Spurengase und Aerosolpartikel beherrscht. Mit den zunehmenden anthropogenen Emissionen von atmosphĂ€rischen Spurengasen, verursacht durch die wachsende Weltbevölkerung und die zunehmende Industrialisierung, wurde in den letzten Dekaden ein globaler Wandel bei der Zusammensetzung der ErdatmosphĂ€re festgestellt: Konzentrationen von atmosphĂ€rischen Spurenstoffen verĂ€ndern sich nicht mehr auf vergleichsweise langsamen geologischen Zeitskalen, sondern mit viel höheren Geschwindigkeiten, in einzelnen FĂ€llen von bis zu einem Prozent pro Jahr. Die wohl bekanntesten Folgen dieser VerĂ€nderungen sind die globale ErwĂ€rmung durch die ansteigenden Emissionen von Treibhausgasen und der mit dem antarktischen 'Ozonloch" entdeckte drastische Ozonverlust in der StratosphĂ€re durch anthropogene Fluor-Chlor-Kohlenwasserstoffe (FCKW). Die Verteilung der fĂŒr Ozonchemie und Klima relevanten Spurengase in der AtmosphĂ€re hĂ€ngt dabei nicht nur von der Verteilung ihrer Quellen und Senken ab, sondern wird maßgeblich durch verschiedene Transportprozesse beeinflußt. Der Austausch zwischen der mit anthropogenen Emissionen belasteten TroposphĂ€re und den höheren AtmosphĂ€renschichten StratosphĂ€re und MesosphĂ€re spielt dabei eine zentrale Rolle. Im Rahmen der Dissertation wurde zum besseren VerstĂ€ndnis von StratosphĂ€ren-TroposphĂ€ren-Austauschprozessen die Verteilung von langlebigen Spurengasen in den beiden atmosphĂ€rischen Kompartimenten TroposphĂ€re und StratosphĂ€re untersucht. Dazu wurde bei einer Meßkampagne im Sommer 1998 im Rahmen des von der EuropĂ€ischen Union geförderten Forschungsprojektes STREAM 98 der flugzeuggetragene Gaschromatograph GhOST (Gas chromatograph for the Observation of Stratospheric Tracers) an Bord einer Cessna Citation II der TU Delft in Höhen bis 13 km eingesetzt. Dabei konnten bei zwanzig Meß- und TransferflĂŒgen ĂŒber Kanada, dem Atlantik und Westeuropa umfangreiche Messungen der langlebigen Spurengase N20, F11 und F12 in der oberen TroposphĂ€re und der Untersten StratosphĂ€re durchgefĂŒhrt werden. Unter Flugbedingungen wurde mit GhOST wĂ€hrend der Kampagne eine Reproduzierbarkeit (1 o) von besser als 0,6 % und eine absolute Genauigkeit von besser als 2 % fĂŒr alle nachgewiesenen Spurengase erreicht. Diese hohe MeßprĂ€zision konnte durch zahlreiche Vergleichsmessungen mit anderen MeßgerĂ€ten und Meßverfahren - im Flugbetrieb und im Labor sichergestellt werden; die LinearitĂ€t des GerĂ€ts wurde zudem mit Hilfe einer barometrisch hergestellten VerdĂŒnnungsreihe untersucht. Die mit GhOST bei STREAM 98 gewonnenen Meßwerte wurden zusammen mit Messungen und Modelldaten der am Projekt beteiligten Arbeitsgruppen zur Untersuchung von Spurengasverteilungen und StratosphĂ€ren-TroposphĂ€ren-Austauschprozessen herangezogen. Untersucht wurden dabei unter anderem die Verteilung und VariabilitĂ€t von N20, F11 und F12 in der TroposphĂ€re und in der Untersten StratosphĂ€re der mittleren Breiten, Austausch- und Mischungsprozesse in der Tropopausenregion und die VariabilitĂ€t von Tracer/Tracer-Korrelationen in der Untersten StratosphĂ€re. Aufbauend auf den Erfahrungen bei STREAM 98 wurde fĂŒr das vom BMBF geförderte Projekt SPURT im Rahmen dieser Doktorarbeit der in-situ-Gaschromatograph GhOST II entwickelt. Unter Beibehaltung der gaschromatographischen Komponenten von GhOST wurden zur Messung der Spurengase SF6 und CO zwei zusĂ€tzliche Detektoren integriert und zahlreiche technische Verbesserungen durchgefĂŒhrt. FĂŒr die vollautomatische rechnergestĂŒtzte Elektronik zur Steuerung des neuen GerĂ€tes wurden zusammen mit der institutseigenen Elektronikwerkstatt verschiedene Baugruppen zur SignalfĂŒhrung und -verarbeitung, zur Temperaturmessung und zur Ansteuerung von Leistungskomponenten entwickelt. WĂ€hrend einer Testkampagne im April 2001 wurde GhOST II erfolgreich mechanisch und elektrisch auf einem Learjet 35A integriert und kam bei zwei MeßflĂŒgen der Meßkampagne SPURT 1 im November 2001 zum Einsatz

    Sleep Disturbances and Suicidality in Posttraumatic Stress Disorder: An Overview of the Literature

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    A causal relationship between sleep disturbances and suicidal behavior has been previously reported. Insomnia and nightmares are considered as hallmarks of posttraumatic stress disorder (PTSD). In addition, patients with PTSD have an increased risk for suicidality. The present article gives an overview about the existing literature on the relationship between sleep disturbances and suicidality in the context of PTSD. It aims to demonstrate that diagnosing and treating sleep problems as still underestimated target symptoms may provide preventive strategies with respect to suicidality. However, heterogeneous study designs, different samples and diverse outcome parameters hinder a direct comparison of studies and a causal relationship cannot be shown. More research is necessary to clarify this complex relationship and to tackle the value of treatment of sleep disturbances for suicide prevention in PTSD

    Rapid eye movements during sleep in mice: High trait-like stability qualifies rapid eye movement density for characterization of phenotypic variation in sleep patterns of rodents

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    <p>Abstract</p> <p>Background</p> <p>In humans, rapid eye movements (REM) density during REM sleep plays a prominent role in psychiatric diseases. Especially in depression, an increased REM density is a vulnerability marker for depression. In clinical practice and research measurement of REM density is highly standardized. In basic animal research, almost no tools are available to obtain and systematically evaluate eye movement data, although, this would create increased comparability between human and animal sleep studies.</p> <p>Methods</p> <p>We obtained standardized electroencephalographic (EEG), electromyographic (EMG) and electrooculographic (EOG) signals from freely behaving mice. EOG electrodes were bilaterally and chronically implanted with placement of the electrodes directly between the musculus rectus superior and musculus rectus lateralis. After recovery, EEG, EMG and EOG signals were obtained for four days. Subsequent to the implantation process, we developed and validated an Eye Movement scoring in Mice Algorithm (EMMA) to detect REM as singularities of the EOG signal, based on wavelet methodology.</p> <p>Results</p> <p>The distribution of wakefulness, non-REM (NREM) sleep and rapid eye movement (REM) sleep was typical of nocturnal rodents with small amounts of wakefulness and large amounts of NREM sleep during the light period and reversed proportions during the dark period. REM sleep was distributed correspondingly. REM density was significantly higher during REM sleep than NREM sleep. REM bursts were detected more often at the end of the dark period than the beginning of the light period. During REM sleep REM density showed an ultradian course, and during NREM sleep REM density peaked at the beginning of the dark period. Concerning individual eye movements, REM duration was longer and amplitude was lower during REM sleep than NREM sleep. The majority of single REM and REM bursts were associated with micro-arousals during NREM sleep, but not during REM sleep.</p> <p>Conclusions</p> <p>Sleep-stage specific distributions of REM in mice correspond to human REM density during sleep. REM density, now also assessable in animal models through our approach, is increased in humans after acute stress, during PTSD and in depression. This relationship can now be exploited to match animal models more closely to clinical situations, especially in animal models of depression.</p

    Problems with Current Dental Documentation in Germany

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    Background: dental documentation is essential for the representation and communication of dental information amongst researchers and practitioners. Dental documentation has to provide the respective means for (a) the representation of the patient status’ and (b) the possible actions. Methods: the consistency of German definitions currently used for dental findings is evaluated by projecting well known examples onto problem axes like “existence of a structure” and “condition of a structure”. Results: it can be shown that current German dental terminology does not support an unambiguous documentation for any situation in dental practice. In some cases, Multiple aspects are merged in several finding statements and make a stringent derivation of the treatment planning difficult. Conclusions: dental documentation in Germany can in some aspects be improved with respect to (a) precision, (b) expressiveness, (c) simplicity and (d) reproducibility. The main axes of dental documentation are enumerated in preparation of a future top-down approach. Clinical Implications: an optimised finding scheme can enhance the communication amongst researchers and practitioners and thus is supposed to improve the treatment quality in the long run

    The Many Faces of Sleep Disorders in Post-Traumatic Stress Disorder: An Update on Clinical Features and Treatment

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    Sleep disorders and nightmares are core symptoms of post-traumatic stress disorder (PTSD). The relationship seems to be bidirectional, and persistent disturbed sleep may influence the course of the disorder. With regard to sleep quality, insomnia and nocturnal anxiety symptoms, as well as nightmares and stressful dreams, are the most prominent sleep symptoms. Polysomnographic measurements reveal alterations of the sleep architecture and fragmentation of rapid eye movement sleep. In addition, sleep disorders, such as sleep-related breathing disorders and parasomnias are frequent comorbid conditions. The complex etiology and symptomatology of trauma-related sleep disorders with frequent psychiatric comorbidity require the application of multimodal treatment concepts, including psychological and pharmacological interventions. However, there is little empirical evidence on the effectiveness of long-term drug treatment for insomnia and nightmares. For nondrug interventions, challenges arise from the current lack of PTSD-treatment concepts integrating sleep- and trauma-focused therapies. Effective therapy for sleep disturbances may consequently also improve well-being during the day and probably even the course of PTSD. Whether early sleep interventions exert a preventive effect on the development of PTSD remains to be clarified in future studies

    Preparations for the Evaluation of a Speech Recognition System in Neonatology (U2)

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    Background: before using a speech recognition system for the neonatal documentation, the underlying neonatal information has to be specified and structured. Up to now, the pre-structuring the first comprehensive examination of newborn (U2) and the respective data set entries has not been described in literature, yet. The common booklet for the documentation of the German U2 does not contain all examinations required nor does it show the choice of all respective finding statements. Objectives: to set up a documentation standard for the U2 distinguishing the most important diseases/disorders at a limited level of detailing. Methods: the finding scheme of the U2 has been specified based on the German national recommendation for the U2. Here, the U2 is the first exhaustive examination of the newborn. Due to a lack of detailed descriptions, the U2 has been formalized and arranged in cooperation with experienced medical experts, which carry out the U2 in daily routine. Results: if all possible finding statements are presented in a hierarchical structure, – even with a small font size – it would cover more than 20 pages. Hence, a more condensed structure has been set up for presentation. If the general practitioner (GP) is to see (a) the finding statements necessary but (b) no more, additional rules can be set up for the masking of finding statements excluded by the results of the prior investigation. Conclusions: the proposed structure for neonatal documentation serves as a basis for statistical analysis. On its basis, investigation can be carried out about (a) problems during the individual examination, (b) problem with the documentation and (c) the benefits of automated speech recognition systems

    Editorial: Sleep, vigilance & disruptive behaviors

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    The Frontiers in Psychiatry Research Theme of Sleep, vigilance, and disruptive behaviors has two aims: first, to promote the understanding of the connections between vigilance and disruptive daytime behavior in the context of sleep deprivation and, second, to explore how naturalistic observations and pattern recognition can play a role in furthering our understanding of these connections. . .
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