Internal sensations as a source of fear: exploring a link between hypoxia and flight phobia

Although flight phobia is very common in the general population, knowledge of the underlying mechanisms is limited. The aim of the current study is to determine whether hypoxia is selectively associated with flight anxiety. We wanted to explore levels of oxygen saturation (SpO2) and the associated subjective somatic sensations in flight phobics and controls. The data collected in this study were obtained from 103 participants: 54 had flight phobia, 49 were controls. SpO2 as well as a subjective report of somatic sensations and anxiety were measured during short haul flights, both at ground level and at cruising altitude. Results indicated that both flight phobics and controls showed a comparable clinical significant decrease in SpO2 from sea level to cruising altitude. Next, at ground level the flight phobic group reported more somatic sensations, most likely due to the elevated levels of anxiety at that point. However, at cruising altitude the flight phobic group still reported more somatic sensations while the level of anxiety was no longer significantly different from controls. This finding points to altered symptom perception in flight phobia and stresses the importance of somatic sensations in this particular phobia

Parameters for Carrot Quality: and the development of the Inner Quality concept

The life processes of the carrot plant were demonstrated by various parameters in this study. Growth processes, including photosynthesis, absorption of nitrogen and other nutrients and formation of cells, tissues and organs, are measured by the parameters weight of leaves and roots and emission 30-50 white of delayed luminescence. The nitrate content may indicate growth but has to be investigated further. Differentiation processes, including refining, ordering, ripening and secondary metabolisms, are measured by the parameters root stumpiness, saccharose, sweetness, dry matter and emission 30-50 ratio of delayed luminescence. Some other parameters may indicate differentiation processes but have to be further investigated: leaves/root weight ratio, monosaccharides/saccharose ratio, carotenes, initial and total emission white, hyperbolicity ratio and slope white of delayed luminescence. Integration of growth and differentiation is measured by resistance to pests and disease, total appreciation and storage test. Some other parameters may indicate integration but need further investigation: carrot taste, slope white of delayed luminescence. Copper chloride crystallisation did not produce clear pictures due to failure of the method applied and should be further investigated since, in the Apple-1 and -2 studies (Bloksma et al., 2001, 2004 b), it was one of the indicators of the life processes. Electro-chemical parameters, except possibly pH, did not indicate growth processes in his study or in the Apple-1 and -2 studies

A Randomized Case-Series Study Comparing the Stability of Implant with Two Different Surfaces Placed in Fresh Extraction Sockets and Immediately Loaded

Background. Hydrophilic and moderately rough implant surfaces have been proposed to enhance the osseointegration response. Aim. The aim of this study was to compare early changes of stability for two implants with identical macrodesign but with different surface topographies. Materials and Methods. In 11 patients, a total of 22 implants (11 bimodal (minimally rough, control) and 11 proactive (moderately rough and hydrophilic, test), Neoss Ltd., Harrogate, UK) were immediately placed into fresh extraction sockets and immediately loaded. The peak insertion torque (IT) was measured in Ncm at placement. Resonance Frequency Analysis (RFA) measurements were made at baseline and 2, 4, 6, and 12 weeks after surgery. Results. The two implant types showed similar IT and RFA values at placement (NS). A dip of RFA values after 2 weeks followed by an increase was observed, where the test implant showed a less pronounced decrease and a more rapid recovery than the control implant. The test implants were significantly more stable than the control ones after 12 weeks. Conclusions. The results from the present study indicated that the hydrophilic and rougher test implant was more resistant to immediate loading and showed a significantly higher stability than the smoother control implant after 12 weeks

Een nieuwe methode om de slaagkans van therapie bespreekbaar te maken

Het voorspellen van behandeluitkomsten is een onderbelicht facet van het klinisch handelen. Ondanks toenemende aandacht voor klinische significantie van bevindingen in uitkomstonderzoek ontbrak een methode om helder te communiceren over behandeleffectiviteit van therapie. In dit artikel bespreken we een nieuwe methode, de probability of treatment benefit tabel, om op een eenvoudigere manier te communiceren over behandeluitkomsten

A short-term clinical study of marginal bone level change around microthreaded and platform-switched implants

PURPOSE: The marginal bone levels around implants following restoration are used as a reference for evaluating implant success and survival. Two design concepts that can reduce crestal bone resorption are the microthread and platform-switching concepts. The aims of this study were to analyze the placement of microthreaded and platform-switched implants and their short-term survival rate, as well as the level of bone around the implants. METHODS: The subjects of this study were 27 patients (79 implants) undergoing treatment with microthreaded and platform-switched implants between October 2008 and July 2009 in the Dental Hospital of Yonsei University Department of Periodontology. The patients received follow-up care more than 6 months after the final setting of the prosthesis, at which time periapical radiographs were taken. The marginal bone level was measured from the reference point to the lowest observed point of contact between the marginal bone and the fixture. Comparisons were made between radiographs taken at the time of fixture installation and those taken at the follow-up visit. RESULTS: During the study period (average of 11.8 months after fixture installation and 7.4 months after the prosthesis delivery), the short-term survival rate of microthreaded and platform-switched implants was 100% and the marginal bone loss around implants was 0.16±0.08 mm, the latter of which is lower than the previously reported values. CONCLUSIONS: This short-term clinical study has demonstrated the successful survival rates of a microthread and platform-switched implant system, and that this system is associated with reduced marginal bone loss.ope

The nature of fear of flying: exploring possible underlying mechanisms in the development of fear of flying

The aim of the present PhD project was to investigate a bio-psychological model about possible underlying working mechanisms of fear of flying. In this model the role of internal stimuli (e.g. bodily sensations) related to specific environmental factors in aviation is explored, as well as information processing factors relevant to interoception. The results showed that biological factors like hypoxia that are a consequence of the cabin environment, do not seem to play a major role in fear of flying: they do not seem to differentiate between flight phobics and controls. On the other hand, information processing of internal sensations seems to be all the more important in fear of flying. Individuals with fear of flying show enhanced processing of words related to internal sensations and they specifically show enhanced interoceptive awareness for respiratory cues. And although it seems that there was no relation with interoceptive awareness regarding cardiac cues, there was an enhanced interoceptive awareness for these cues in individuals with fear of flying low in anxiety sensitivity (AS). AS revealed to be of key importance in fear of flying. Throughout the studies, it was shown that the fear of flying samples had higher levels of AS. Moreover, two studies specifically studying the role of AS in fear of flying demonstrated that AS moderates the relationship between somatic sensations and flight anxiety. In individuals higher in AS, somatic sensations significantly predict flight anxiety, while this is not the case for individuals lower in AS. To summarize, the current investigation into a bio-psychological etiological model of fear of flying has shown that the proposed biological factors do not seem play a major role, whereas psychological factors are the ones that really matter. In relation to this general conclusion we would like to quote the conclusion of a review by McNally (2002): “The psychological response to bodily sensations and not differences in the magnitude of physiological changes determines whether an individual will become anxious or fearful.”

Quels sont les effets des stratégies des traders à haute fréquence sur le marché des actions américain?

Ce mémoire a pour question de recherche les effets des stratégies de traders à haute fréquence sur le marché des actions américain. Pour ce faire, il est décomposé en trois parties dont la première étudie les événements historiques et les diverses régulations qui ont mené à l’essor du trading à haute fréquence aux Etats-Unis. Dans cette même partie sont définis le trading algorithmique et le trading à haute fréquence dont l’analyse des principales caractéristiques clôture celle-ci. En seconde partie, il est procédé à l’analyse détaillée des stratégies les plus couramment utilisées par les traders à haute fréquence. Celles-ci sont regroupées en quatre catégories, les stratégies de market making, les stratégies d’arbitrage, les stratégies directionnelles et les stratégies structurelles. Enfin, la troisième et dernière partie est une revue de littérature visant à regrouper les études scientifiques ayant étudié l’impact du trading à haute fréquence sur différents critères d’évaluation de la qualité d’un marché d’action. Ces quatre critères sont la liquidité, le spread, la volatilité et la formation des prix. En conclusion, le consens scientifique semble indiquer que les stratégies de market making des traders à haute fréquence contribuent à l’amélioration de la liquidité du marché des actions américain. Ensuite, il semble que ces mêmes stratégies aient contribué partiellement à la diminution du spread observée sur le marché des actions américain depuis le début des années 2000. D’autres études ont également mis en avant que les stratégies directionnelles et les stratégies d’arbitrage utilisées par les traders à haute fréquence améliorent le processus de formation des prix, notamment grâce à une intégration plus rapide de l'information. Quant aux effets de ces stratégies sur la volatilité du marché, les avis sont plus mitigés. Certains auteurs estiment que ces stratégies contribuent à diminuer la volatilité du marché alors que d’autres en sont arrivés à la conclusion que ces stratégies exacerbent la volatilité du marché en cas d’extrême variation.Master [120] en sciences de gestion, Université catholique de Louvain, 201