Pre-stimulus influences on auditory perception arising from sensory representations and decision processes

The qualities of perception depend not only on the sensory inputs but also on the brain state before stimulus presentation. Although the collective evidence from neuroimaging studies for a relation between prestimulus state and perception is strong, the interpretation in the context of sensory computations or decision processes has remained difficult. In the auditory system, for example, previous studies have reported a wide range of effects in terms of the perceptually relevant frequency bands and state parameters (phase/power). To dissociate influences of state on earlier sensory representations and higher-level decision processes, we collected behavioral and EEG data in human participants performing two auditory discrimination tasks relying on distinct acoustic features. Using single-trial decoding, we quantified the relation between prestimulus activity, relevant sensory evidence, and choice in different task-relevant EEG components. Within auditory networks, we found that phase had no direct influence on choice, whereas power in task-specific frequency bands affected the encoding of sensory evidence. Within later-activated frontoparietal regions, theta and alpha phase had a direct influence on choice, without involving sensory evidence. These results delineate two consistent mechanisms by which prestimulus activity shapes perception. However, the timescales of the relevant neural activity depend on the specific brain regions engaged by the respective task

Additional time-dependent phase in the flavor-conversion formulas

In the framework of intermediate wave-packets for treating flavor oscillations, we quantify the modifications which appear when we assume a strictly peaked momentum distribution and consider the second-order corrections in a power series expansion of the energy. By following a sequence of analytic approximations, we point out that an extra time-dependent phase is merely the residue of second-order corrections. Such phase effects are usually ignored in the relativistic wave-packet treatment, but they do not vanish non-relativistically and can introduce some small modifications to the oscillation pattern even in the ultra-relativistic limit.Comment: 9 pages, 3 figure

Development and testing of a virtual nursing intervention to increase walking after a cardiac event : a randomized trial

Bien que l'augmentation de l'activité physique entraîne plusieurs effets bénéfiques sur la santé après un syndrome coronarien aigu (Anderson et al., 2016; Moholdt, Lavie, & Nauman, 2018), seulement 40 à 60% des patients coronariens atteignent le niveau d'activité physique recommandé (De Smedt et al., 2016; Janssen & Jolliffe, 2006; Reid et al., 2006). Bien que les interventions sur le Web offrent de nouvelles modalités permettant de rejoindre de larges populations de patients coronariens, peu d’études ont utilisé des mesures objectives de l’activité physique pour en évaluer les effets (Devi et al., 2015). Le développement d'une intervention infirmière personnalisée sur le Web de quatre semaines, TAVIE en m@rche, a été guidé par l’approche de soins fondée sur les forces et la théorie de l'autodétermination. Le but de l'intervention était d'augmenter la durée de la marche à pied d'intensité modérée à 150 minutes par semaine, comme recommandé chez des patients coronariens insuffisamment actifs. L’intervention est centrée sur les vidéos d'une infirmière proposant un contenu adapté aux niveaux de la motivation autonome, de la compétence perçue et de la marche à pied auto-rapportée. Le but primaire de cet essai contrôlé randomisé multicentrique à deux groupes parallèles était de tester l'effet de TAVIE en m@rche sur l'augmentation du nombre de pas par jour à douze semaines post-randomisation. Les buts secondaires visaient à évaluer l'effet de l'intervention sur l'augmentation du nombre de pas par jour à cinq semaines ainsi que l'augmentation de la marche à pied et de l'activité physique modérée à vigoureuse à cinq et douze semaines. Nous avons également exploré l'effet de l'intervention sur la motivation et la confiance à atteindre la recommandation pour la marche à pied ainsi que sur la qualité de vie, le tabagisme, l’adhérence à la médication cardiaque, la participation à un programme de prévention secondaire, les visites aux urgences, les hospitalisations et la fréquence des douleurs angineuses. Les patients présentant un syndrome coronarien aigu éligible devaient déclarer un niveau d'activité physique inférieur à celui recommandé durant les six mois avant l'hospitalisation et pouvoir accéder à l'intervention sur le Web. La randomisation a eu lieu entre la quatrième et la sixième semaine post-hospitalisation au cours desquelles les participants ont été assignés au hasard au groupe expérimental, pour recevoir TAVIE en m@rche, ou au groupe contrôle, pour recevoir des hyperliens vers des sites Web publics. Les données ont été collectées à cinq et douze semaines selon les buts de l’étude. Soixante participants ont été randomisés dans les deux groupes et trente-neuf ont fourni des données complètes sur le résultat principal. À douze semaines, en comparaison au groupe contrôle, une augmentation minimale, mais non-significative, du nombre de pas par jour ainsi qu’une amélioration notable sur le plan clinique, mais non-significative, de l'activité physique d'intensité modérée à vigoureuse ont été observées dans le groupe expérimental. Aucune différence significative n'a été observée entre les groupes en ce qui concerne les autres buts secondaires et exploratoires. L’augmentation minimale et non-significative observée quant au résultat principal pourrait s’expliquer par le fait que la plupart des participants avaient déjà augmenté leur nombre de pas par jour avant même d'avoir accès à l'intervention. L'amélioration sur le plan clinique de l'activité physique modérée à vigoureuse, même si non-significative, pourrait néanmoins être bénéfique à la santé. Cependant, l’interprétation de ce résultat est faite avec prudence en raison des limites suivantes: les types d'activités physiques qui auraient pu expliquer cette amélioration n'ont pas été collectés, un risque de biais lié à l’attrition est présent et la marge d’erreur est grande vu le petit nombre de participants. Cette étude contribue néanmoins à l'avancement de la théorie en proposant une conceptualisation et une opérationnalisation solide d'une nouvelle intervention infirmière sur le Web. Les contributions empiriques découlent des réflexions sur les adaptations possibles de l'intervention et du devis de la recherche et qui permettraient de mieux atteindre la population-cible et de mieux répondre à leurs besoins de soutien pour accroître l'activité physique.Although increasing physical activity produces several health benefits after an acute coronary syndrome event (Anderson et al., 2016; Moholdt et al., 2018), only 40 to 60% of coronary patients attain the recommended physical activity level (De Smedt et al., 2016; Janssen & Jolliffe, 2006; Reid et al., 2006). Whereas web-based interventions offer novel modalities scalable to large populations of coronary patients, there is a paucity of evidence using objective measures of physical activity behaviour (Devi et al., 2015). The development of a four-week web-based tailored nursing intervention, TAVIE en m@rche, was guided by a framework integrating Strengths-Based Nursing Care and Self-Determination Theory. The intervention goal was to increase moderate-intensity walking to the recommended 150 minutes per week in insufficiently active acute coronary syndrome patients. The intervention is centered on videos of a nurse delivering content tailored to baseline self-reported autonomous motivation, perceived competence, and walking behavior. The primary aim of this parallel two-group multicenter randomized controlled trial was to test the effect of TAVIE en m@rche on increasing steps per day at twelve-weeks post-randomization. Secondary aims included testing the effect of the intervention on increasing steps per day at five weeks, and increasing walking and moderate to vigorous physical activity at five and twelve weeks. We also explored the effect of the intervention on motivation and confidence to attain the walking recommendation, quality of life, smoking status, cardiac medication adherence, secondary prevention program attendance, emergency department visits, hospitalizations, and angina frequency. Eligible acute coronary syndrome patients reported performing less than the recommended physical activity level six-months prior hospitalization and having the ability to access the web-based intervention. Randomization occurred between the fourth and sixth week post-hospitalization upon which the participants were assigned to either the experimental group, receiving TAVIE en m@rche, or the control group, receiving hyperlinks to public websites. Outcome data were collected at five and or twelve weeks according to the aims. Sixty participants were randomized equally among the two groups, in which thirty-nine provided completed data for the primary outcome. At twelve weeks, relative to the control v groupe, a minimal and non-significant increase in steps per day as well as a non-significant improvement in moderate to vigorous intensity physical activity were found in the experimental group. No significant effects were observed between groups regarding other secondary or any exploratory outcomes. The minimal and non-significant increase in the primary outcome may be explained by most participants attaining the intervention goal before receiving access to the intervention. The magnitude of improvement in moderate to vigorous physical activity, albeit non-significant, could nonetheless represent important health gains in the experimental group. However, caution in interpretation is warranted in this result for the following limitations: the types of physical activities that could have explained this improvement were not collected, a risk of attrition bias was present, and the result shows statistical uncertainty that occurred from a small sample size. This study contributes to the advancement of theory in intervention design by demonstrating the conceptualization and operationalization of a novel web-based intervention using a nursing approach. Empirical contributions arise from stimulating thinking on possible adaptions of the intervention and research design to best reach the intended population for intervention and to best meet their needs for support in increasing physical activity

A study in developing a positive self concept in preschool children

The purpose of this study is threefold. One is to find out if a positive self concept develops when four and five year old nursery school children are exposed to sensory activities, and secondly, to compare this growth with four and five year old nursery school children who have not participated in such a program. The third purpose is to find out if the younger children have a greater growth toward positive self concept than the older children

Neutrino oscillations and the effect of the finite lifetime of the neutrino source

We consider a neutrino source at rest and discuss a condition for the existence of neutrino oscillations which derives from the finite lifetime $\tau_S$ of the neutrino source particle. This condition is present if the neutrino source is a free particle such that its wave function is non-stationary. For a Gaussian wave function and with some simplifying assumptions, we study the modification of the usual oscillation probability stemming from $\tau_S$. In the present accelerator experiments the effect of $\tau_S$ can be neglected. We discuss some experimental situations where the source lifetime becomes relevant in the oscillation formula.Comment: 13 pages latex file with 2 figure

Grid computing in image analysis

Diagnostic surgical pathology or tissue–based diagnosis still remains the most reliable and specific diagnostic medical procedure. The development of whole slide scanners permits the creation of virtual slides and to work on so-called virtual microscopes. In addition to interactive work on virtual slides approaches have been reported that introduce automated virtual microscopy, which is composed of several tools focusing on quite different tasks. These include evaluation of image quality and image standardization, analysis of potential useful thresholds for object detection and identification (segmentation), dynamic segmentation procedures, adjustable magnification to optimize feature extraction, and texture analysis including image transformation and evaluation of elementary primitives

E-education in pathology including certification of e-institutions

E–education or electronically transferred continuous education in pathology is one major application of virtual microscopy. The basic conditions and properties of acoustic and visual information transfer, of teaching and learning processes, as well as of knowledge and competence, influence its implementation to a high degree. Educational programs and structures can be judged by access to the basic conditions, by description of the teaching resources, methods, and its program, as well as by identification of competences, and development of an appropriate evaluation system. Classic teaching and learning methods present a constant, usually non-reversible information flow. They are subject to personal circumstances of both teacher and student. The methods of information presentation need to be distinguished between static and dynamic, between acoustic and visual ones. Electronic tools in education include local manually assisted tools (language assistants, computer-assisted design, etc.), local passive tools (slides, movies, sounds, music), open access tools (internet), and specific tools such as Webinars. From the medical point of view information content can be divided into constant (gross and microscopic anatomy) and variable (disease related) items. Most open access available medical courses teach constant information such as anatomy or physiology. Mandatory teaching resources are image archives with user–controlled navigation and labelling, student–oriented user manuals, discussion forums, and expert consultation. A classic undergraduate electronic educational system is WebMic which presents with histology lectures. An example designed for postgraduate teaching is the digital lung pathology system. It includes a description of diagnostic and therapeutic features of 60 rare and common lung diseases, partly in multimedia presentation. Combining multimedia features with the organization structures of a virtual pathology institution will result in a virtual pathology education institution (VPEI), which can develop to a partly automated distant learning faculty in medicine

Space-time description of neutrino flavour oscillations

Recently the issue of EPR-like correlations in the mutual probability of detecting neutrino together with accompanying charged lepton has received a new impetus. In this paper we describe this effect using the propagators of the particles involved in the Schwinger's parametric integral representation. We find this description more simple and more suitable to the purpose than the usual momentum-space analysis. We consider the cases of monochromatic neutrino source, wave packet source, and neutrino creation in a localised space-time region. In the latter case we note that the space-time oscillation amplitude depends on the values of the neutrino masses, and becomes rather small for large relative mass differences (mass hierarchy). We obtain the expressions for the oscillation and coherence lengths in various circumstances. In the region of overlap our results confirm those of Dolgov et al. [hep-ph/9703241].Comment: 19 pages, latex, epsfig, 1 figure; text slightly extended, some errors corrected and Appendix is adde

Remarks upon the mass oscillation formulas

The standard formula for mass oscillations is often based upon the approximation $t \approx L$ and the hypotheses that neutrinos have been produced with a definite momentum $p$ or, alternatively, with definite energy $E$. This represents an inconsistent scenario and gives an unjustified reduction by a factor of two in the mass oscillation formulas. Such an ambiguity has been a matter of speculations and mistakes in discussing flavour oscillations. We present a series of results and show how the problem of the factor two in the oscillation length is not a consequence of gedanken experiments, i.e. oscillations in time. The common velocity scenario yields the maximum simplicity.Comment: 9 pages, AMS-Te

Real Oscillations of Virtual Neutrinos

We study the conditions for neutrino oscillations in a field theoretical approach by taking into account that only the neutrino production and detection processes, which are localized in space around the coordinates $\vec{x}_P$ and $\vec{x}_D$, respectively, can be manipulated. In this sense the neutrinos whose oscillations are investigated appear as virtual lines connecting production with detection in the total Feynman graph and all neutrino fields or states to be found in the discussion are mass eigenfields or eigenstates. We perform a thorough examination of the integral over the spatial components of the inner neutrino momentum and show that in the asymptotic limit $L=|\vec{x}_D - \vec{x}_P| \rightarrow \infty$ the virtual neutrinos become ``real'' and under certain conditions the usual picture of neutrino oscillations emerges without ambiguities.Comment: 12 pages, pure LaTeX file, no figure