449 research outputs found
The functional relationship between yawning and vigilance
No full textBACKGROUND: Although yawning is a ubiquitous and phylogenetically old phenomenon, its origin and purpose remain unclear. The study aimed at testing the widely held hypothesis that yawning is triggered by drowsiness and brings about a reversal or suspension of the process of falling asleep. METHODS: Subjects complaining of excessive sleepiness were spontaneously yawning while trying to stay awake in a quiet and darkened room. Changes in their electroencephalogram (EEG) and heart rate variability (HRV) associated with yawning were compared to changes associated with isolated voluntary body movements. Special care was taken to remove eye blink- and movement-artefacts from the recorded signals. RESULTS: Yawns were preceded and followed by a significantly greater delta activity in EEG than movements (p< or =0.008). After yawning, alpha rhythms were attenuated, decelerated, and shifted towards central brain regions (p< or =0.01), whereas after movements, they were attenuated and accelerated (p<0.02). A significant transient increase of HRV occurred after the onset of yawning and movements, which was followed by a significant slow decrease peaking 17s after onset (p<0.0001). No difference in HRV changes was found between yawns and movements. CONCLUSIONS: Yawning occurred during periods with increased drowsiness and sleep pressure, but was not followed by a measurable increase of the arousal level of the brain. It was neither triggered nor followed by a specific autonomic activation. Our results therefore confirm that yawns occur due to sleepiness, but do not provide evidence for an arousing effect of yawning
Family and Everyday Life in Selected Tales by Ignat Herrmann
No full textVe své diplomové práci jsem se zaměřila na systematický rozbor několika vybraných povídek spisovatele Ignáta Herrmanna. Ignát Herrmann (1854-1935) byl novinářem, fejetonistou, romanopiscem, autorem mnoha povídek a vzpomínek na starou Prahu. K jeho nejznámějším dílům patří existenciální román U snědeného krámu a humoristický román Otec Kondelík a ženich Vejvara. Ve své práci jsem se orientovala na způsob zobrazení jednotlivých postav v rámci jejich fikčních světů, které jsou tvořeny především rodinným prostředím. Ve vybraných dílech jsem analyzovala literární ztvárnění rodiny, vzájemných rodinných vztahů a každodennosti. Výzkum jsem zaměřila na díla vydaná mezi lety 1893 až 1913 s důrazem na různě zobrazené téma rodiny. Pro svůj výzkum jsem vybrala povídky z těchto svazků povídkových souborů: Evička a jiné výjevy rodinné, Páté přes deváté, Rodiny a rodinky, Staří mládenci, Z pamětí starého mrzouta. Jako metodu výzkumu jsem zvolila analýzu z hlediska skladby, počtu a typologie členů jednotlivých rodin, jejich vzájemných vazeb a vztahů, rodinných událostí a každodennosti.In my work, I have focused to stance of making literature family, its members and relations in the writings of Ignát Herrmann. Ignát Herrmann (1854-1935) was a reporter, feulletonist, author of novels, tales and memories of Prague. His most familiar writings are: Otec Kundelík a ženich Vejvara, U snědeného krámu and Vdavky Nanynky Kulichové. I have worked with writings publicated between years 1893 and 1913, and I focused on the common relation theme of family. To my research, I have chosen novels: Evička a jiné výjevy rodinné, Páté přes deváté, Rodiny a rodinky, Staří mládenci, Z pamětí starého mrzouta. Used reserch method has been analytics. I have examined every role played by characters of a novel family. Factualy there are fathers, mothers, children, husbands, brides and married couples. I have taken care of showing common days in chosen writings.Ústav historických vědPrezentace magisterské diplomové práce.
Komise byla seznámena s posudky vedoucího práce a opnonenta.
Diplomantka reagovala na posudky a vznesené otázky.Dokončená práce s úspěšnou obhajobo
S-heterocyclic carbene with a disilane backbone
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EEG correlation and power during maintenance of wakefulness test after sleep-deprivation
No full textTo investigate whether there are any objective EEG characteristics that change significantly between specific time periods during maintenance of wakefulness test (MWT) and whether such changes are associated with the ability to appropriately communicate sleepiness
Naturalizing institutions: Evolutionary principles and application on the case of money
No full textIn recent extensions of the Darwinian paradigm into economics, the replicator-interactor duality looms large. I propose a strictly naturalistic approach to this duality in the context of the theory of institutions, which means that its use is seen as being always and necessarily dependent on identifying a physical realization. I introduce a general framework for the analysis of institutions, which synthesizes Searle's and Aoki's theories, especially with regard to the role of public representations (signs) in the coordination of actions, and the function of cognitive processes that underly rule-following as a behavioral disposition. This allows to conceive institutions as causal circuits that connect the population-level dynamics of interactions with cognitive phenomena on the individual level. Those cognitive phenomena ultimately root in neuronal structures. So, I draw on a critical restatement of the concept of the meme by Aunger to propose a new conceptualization of the replicator in the context of institutions, namely, the replicator is a causal conjunction between signs and neuronal structures which undergirds the dispositions that generate rule-following actions. Signs, in turn, are outcomes of population-level interactions. I apply this framework on the case of money, analyzing the emotions that go along with the use of money, and presenting a stylized account of the emergence of money in terms of the naturalized Searle-Aoki model. In this view, money is a neuronally anchored metaphor for emotions relating with social exchange and reciprocity. Money as a meme is physically realized in a replicator which is a causal conjunction of money artefacts and money emotions. --Generalized Darwinism,institutions,replicator/interactor,Searle,Aoki,naturalism,memes,emotions,money
Mechanisms underlying prion protein toxicity and therapeutic strategies
No full textPrion diseases such as Creutzfeldt-Jakob disease (CJD) and Kuru in humans, scrapie in sheep and bovine spongiform encephalopathy (BSE) in cattle are a group of neurodegenerative diseases that invariably lead to death. The current hypothesis states that the cellular prion protein (PrPC) gets converted into a misfolded form
PrPSc, characterized by a high β-sheet content (Aguzzi and Calella, 2009). The misfolded PrPSc oligomerizes and grows into fibrils. Broken fibrils can then serve as a
seed and lead to further conversion and oligomerization, and therefore be used as a surrogate for infectivity (Knowles et al., 2009). The in vivo conformation of prion fibrils is not defined; hence, developing specific inhibitors remains challenging.
Other therapies targeting both prion replication and the intracellular signalling pathways that mediate neurotoxicity have not been successful. Consequently, to date no effective prion therapy exists.
Prion disease represents one if not the best-studied protein aggregation disease. An in vitro model for prion-induced pathology has been established in our laboratory.
When cerebellar organotypic cultured slices (COCS) are infected with prions, they exhibit all the characteristic features as prion replication, astro- and microgliosis,
vacuolation and neurotoxicity (Falsig et al., 2008; Falsig et al., 2012).
Luminescent conjugated polythiophenes (LCP) are polymeric fluorescent molecules that preferentially bind to protein aggregates with regular cross-β-sheet structures,
including those formed by PrPSc, and can be used to stain many different amyloids in tissues (Klingstedt and Nilsson, 2012). Recently, our laboratory found that treatment of prion-infected brain homogenates and prion-infected COCS with LCPs reduced infectivity. Interestingly, the prionostatic effect seems to rely on hyperstabilization, rather than dissociation, of PrP aggregates (Margalith et al., 2012).
More recent findings from our lab have shown that full length, monovalent antibodies or single chain antibodies that target the globular domain (termed globular domain ligands; GDL) of prion protein (PrPC) lead to dramatic neuronal cell loss when applied in cultured organotypic cerebellar slices or stereotactically injected in the cerebellum of mice (Sonati et al., 2013). It was also found that neurotoxicity involves the production of reactive oxygen species and activation of calpains.
This thesis focuses on the evaluation of LCPs as a therapy in a mouse model of prion diseases, the comparison of the pathogenetic mechanisms underlying neurotoxicity elicited by GDL or prions and signaling mechanisms involved in prion induced neuronal cell death
Eyelid Closure Behavior of Patients with Idiopathic and Nonorganic Hypersomnia, Narcolepsy-Cataplexy, and Healthy Controls in the Maintenance of Wakefulness Test
No full textPURPOSE
Differential diagnosis of central disorders of hypersomnolence remains challenging, particularly between idiopathic (IH) and nonorganic hypersomnia (NOH). We hypothesized that eyelid closure behavior in the maintenance of wakefulness test (MWT) could be a valuable biomarker.
PATIENTS AND METHODS
MWT recordings of patients with IH, NOH, narcolepsy-cataplexy (NC), and healthy sleep-deprived controls (H) were retrospectively analyzed (15 individuals per group). For each MWT trial, visual scoring of face videography for partial (50-80%) and full eyelid closure (≥80%) was performed from "lights off" to the first microsleep episode (≥3 s).
RESULTS
In all groups, the frequency and cumulative duration of periods with partial and full eyelid closure gradually increased toward the first microsleep episode. On the group level, significant differences occurred for the latency to the first microsleep episode (IH 21 min (18-33), NOH 23 min (17-35), NC 11 min (7-19), H 10 min (6-25); p = 0.009), the ratio between partial and full eyelid closure duration (IH 2.2 (0.9-3.1), NOH 0.5 (0-1.2), NC 2.8 (1.1-5), H 0.7 (0.4-3.3); p = 0.004), and the difference between full and partial eyelid closure duration in the five minutes prior to the first microsleep episode (∆full - partial eyelid closure duration: IH -16 s (-35 to 28); NOH 46 s (9-82); NC -6 s (-26 to 5); H 10 s (-4 to 18); p = 0.007). IH and NOH significantly differed comparing the ratio between partial and full eyelid closure (p = 0.005) and the difference between ∆full - partial eyelid closure duration in the five minutes prior to the first microsleep episode (p = 0.006).
CONCLUSION
In the MWT, eyelid closure behavior (∆full - partial) in the period prior to the first microsleep episode could be of value for discriminating NOH from other etiologies of excessive daytime sleepiness, particularly IH
What's Yours Is Mine and What's Mine Is Mine: Why Tarrant Regional Water District v. Herrmann Signals the Need for Texas to Initiate Interstate Water Compact Modifications
No full textThis article analyzes the Supreme Court’s decision in Tarrant Regional Water District v. Herrmann and its implications for Texas’s water rights. The article explores how the ruling, which denied Texas access to water located in Oklahoma under the Red River Compact, underscores the limitations of existing interstate water agreements. The author argues that increasing population growth, drought, and competing demands make current compacts inadequate for addressing modern water challenges. She advocates for proactive renegotiation and modification of interstate compacts to ensure equitable and sustainable water allocation. Ultimately, the article urges Texas policymakers to pursue cooperative reforms that balance state sovereignty with the region’s shared water needs
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