114 research outputs found

    A model of horse mussel reef formation in the Bay of Fundy based on population growth and geological processes

    Get PDF
    From a total of 14 geological sediment provinces recognized in the Bay of Fundy only five: sand with bioherms, gravel/cobble, gravel /scallop bed, mottled gravel and glacio-marine mud were found to have significant populations of the horse mussel, Modiolus modiolus. Valve increment measures of annual growth rings in the early years of life of populations of these Bay of Fundy horse mussels, suggest that growth rates vary with the geological province where they are found. Horse mussel populations grow fastest on sand with bioherms, closely followed by those growing on gravel/scallop bed; the slowest growing are found on gravel/ cobble and mottled gravel geological provinces. Multibeam bathymetry and backscatter data have been collected in an area of mussel reefs in the central part of the Bay of Fundy. The data indicates that the mussel reefs (bioherms) tend to occur on the eastern side of small, gravel covered, glacial ridges on the seabed and form a variety of single and multiple, long and short reefs that rise above the seabed up to 3 m high. They are always associated with sand in transport at the seabed in a variety of bedforms. A conceptual model of formation and location is presented that considers: current velocity and turbulence, well-mixed water masses, seabed morphology, sediment distribution and sediment transport, as causative factors. RÉSUMÉ D’un total de 14 classes de sédiments géologiques reconnues dans la baie de Fundy, seulement cinq (biohermes, gravier/galets, gravier/fond de pétoncle, gravier tacheté et boue glacio-marine) renfermaient des populations importantes de modiole Modiolus modiolus. Les mesures de l’augmentation valvaire des cernes d’accroissement annuels durant les premières années de vie des populations de modioles dans la baie de Fundy indiqueraient que les taux de croissance varient selon la classe de sédiment géologique où ils se trouvent. Les populations de modioles croissent plus rapidement dans le sable renfermant des biohermes, et la croissance est presque aussi grande chez les modioles présents dans les classes de sédiments composées de gravier/fond de pétoncles; la croissance la plus lente a été observée dans les classes de sédiments géologiques composées de gravier/galets et de gravier tacheté. Des données ont été recueillies au moyen de la bathymétrie par secteurs et de la rétrodiffusion dans une zone de récifs de moules de la partie centrale de la baie de Fundy. Les données indiquent que les récifs de moules (biohermes) semblent se former sur le côté est de petites crêtes glaciaires recouvertes de gravier sur le plancher sous‑marin, et qu’ils forment divers récifs uniques et multiples, longs et courts, qui s’élèvent sur le plancher sous-marin jusqu’à une hauteur de trois mètres. Ils sont toujours associés avec le sable déplacé sur le plancher sous-marin dans diverses morphologies de fond. On présente un modèle conceptuel de la formation et de l’emplacement qui considère comme facteurs de causalité les éléments suivants : la vitesse et la turbulence actuelles, les masses d’eau homogènes, la morphologie du plancher sous-marin, la répartition des sédiments et les transports sédimentaires. [Traduit par la redaction

    A research agenda for Fundy: results from the 2006 ‘Fundy Session’ at the Atlantic Geoscience Society Colloquium

    Get PDF
    Publisher's version/PDFAbstract of a presentation from the Atlantic Geoscience Society 2008 Colloquium and Annual General Meeting held at the Holiday Inn Harbourside, Dartmouth, Nova Scotia, on February 1 and 2, 2008

    Illumination of Parainfluenza Virus Infection and Transmission in Living Animals Reveals a Tissue-Specific Dichotomy

    Get PDF
    The parainfluenza viruses (PIVs) are highly contagious respiratory paramyxoviruses and a leading cause of lower respiratory tract (LRT) disease. Since no vaccines or antivirals exist, non-pharmaceutical interventions are the only means of control for these pathogens. Here we used bioluminescence imaging to visualize the spatial and temporal progression of murine PIV1 (Sendai virus) infection in living mice after intranasal inoculation or exposure by contact. A non-attenuated luciferase reporter virus (rSeV-luc(M-F*)) that expressed high levels of luciferase yet was phenotypically similar to wild-type Sendai virus in vitro and in vivo was generated to allow visualization. After direct intranasal inoculation, we unexpectedly observed that the upper respiratory tract (URT) and trachea supported robust infection under conditions that result in little infection or pathology in the lungs including a low inoculum of virus, an attenuated virus, and strains of mice genetically resistant to lung infection. The high permissivity of the URT and trachea to infection resulted in 100% transmission to naïve contact recipients, even after low-dose (70 PFU) inoculation of genetically resistant BALB/c donor mice. The timing of transmission was consistent with the timing of high viral titers in the URT and trachea of donor animals but was independent of the levels of infection in the lungs of donors. The data therefore reveals a disconnect between transmissibility, which is associated with infection in the URT, and pathogenesis, which arises from infection in the lungs and the immune response. Natural infection after transmission was universally robust in the URT and trachea yet limited in the lungs, inducing protective immunity without weight loss even in genetically susceptible 129/SvJ mice. Overall, these results reveal a dichotomy between PIV infection in the URT and trachea versus the lungs and define a new model for studies of pathogenesis, development of live virus vaccines, and testing of antiviral therapies

    Discrete Emotion Effects on Lexical Decision Response Times

    Get PDF
    Our knowledge about affective processes, especially concerning effects on cognitive demands like word processing, is increasing steadily. Several studies consistently document valence and arousal effects, and although there is some debate on possible interactions and different notions of valence, broad agreement on a two dimensional model of affective space has been achieved. Alternative models like the discrete emotion theory have received little interest in word recognition research so far. Using backward elimination and multiple regression analyses, we show that five discrete emotions (i.e., happiness, disgust, fear, anger and sadness) explain as much variance as two published dimensional models assuming continuous or categorical valence, with the variables happiness, disgust and fear significantly contributing to this account. Moreover, these effects even persist in an experiment with discrete emotion conditions when the stimuli are controlled for emotional valence and arousal levels. We interpret this result as evidence for discrete emotion effects in visual word recognition that cannot be explained by the two dimensional affective space account

    Smoking patterns and stimulus control in intermittent and daily smokers

    Get PDF
    Intermittent smokers (ITS) - who smoke less than daily - comprise an increasing proportion of adult smokers. Their smoking patterns challenge theoretical models of smoking motivation, which emphasize regular and frequent smoking to maintain nicotine levels and avoid withdrawal, but yet have gone largely unexamined. We characterized smoking patterns among 212 ITS (smoking 4-27 days per month) compared to 194 daily smokers (DS; smoking 5-30 cigarettes daily) who monitored situational antecedents of smoking using ecological momentary assessment. Subjects recorded each cigarette on an electronic diary, and situational variables were assessed in a random subset (n = 21,539 smoking episodes); parallel assessments were obtained by beeping subjects at random when they were not smoking (n = 26,930 non-smoking occasions). Compared to DS, ITS' smoking was more strongly associated with being away from home, being in a bar, drinking alcohol, socializing, being with friends and acquaintances, and when others were smoking. Mood had only modest effects in either group. DS' and ITS' smoking were substantially and equally suppressed by smoking restrictions, although ITS more often cited self-imposed restrictions. ITS' smoking was consistently more associated with environmental cues and contexts, especially those associated with positive or "indulgent" smoking situations. Stimulus control may be an important influence in maintaining smoking and making quitting difficult among ITS. © 2014 Shiffman et al

    The MPI Facial Expression Database — A Validated Database of Emotional and Conversational Facial Expressions

    Get PDF
    The ability to communicate is one of the core aspects of human life. For this, we use not only verbal but also nonverbal signals of remarkable complexity. Among the latter, facial expressions belong to the most important information channels. Despite the large variety of facial expressions we use in daily life, research on facial expressions has so far mostly focused on the emotional aspect. Consequently, most databases of facial expressions available to the research community also include only emotional expressions, neglecting the largely unexplored aspect of conversational expressions. To fill this gap, we present the MPI facial expression database, which contains a large variety of natural emotional and conversational expressions. The database contains 55 different facial expressions performed by 19 German participants. Expressions were elicited with the help of a method-acting protocol, which guarantees both well-defined and natural facial expressions. The method-acting protocol was based on every-day scenarios, which are used to define the necessary context information for each expression. All facial expressions are available in three repetitions, in two intensities, as well as from three different camera angles. A detailed frame annotation is provided, from which a dynamic and a static version of the database have been created. In addition to describing the database in detail, we also present the results of an experiment with two conditions that serve to validate the context scenarios as well as the naturalness and recognizability of the video sequences. Our results provide clear evidence that conversational expressions can be recognized surprisingly well from visual information alone. The MPI facial expression database will enable researchers from different research fields (including the perceptual and cognitive sciences, but also affective computing, as well as computer vision) to investigate the processing of a wider range of natural facial expressions

    Using viral vectors as gene transfer tools (Cell Biology and Toxicology Special Issue: ETCS-UK 1 day meeting on genetic manipulation of cells)

    Get PDF
    In recent years, the development of powerful viral gene transfer techniques has greatly facilitated the study of gene function. This review summarises some of the viral delivery systems routinely used to mediate gene transfer into cell lines, primary cell cultures and in whole animal models. The systems described were originally discussed at a 1-day European Tissue Culture Society (ETCS-UK) workshop that was held at University College London on 1st April 2009. Recombinant-deficient viral vectors (viruses that are no longer able to replicate) are used to transduce dividing and post-mitotic cells, and they have been optimised to mediate regulatable, powerful, long-term and cell-specific expression. Hence, viral systems have become very widely used, especially in the field of neurobiology. This review introduces the main categories of viral vectors, focusing on their initial development and highlighting modifications and improvements made since their introduction. In particular, the use of specific promoters to restrict expression, translational enhancers and regulatory elements to boost expression from a single virion and the development of regulatable systems is described
    corecore