Search results for "Avoidance"

A new apparatus for the study of avoidance conditioning in fishes

1981

An apparatus for the study of avoidance conditioning in fishes is described. The chamber is cylindrical in shape, with shocking electrodes placed above and below the animals, and response is defined as swimming a predetermined distance in either direction along a circumferential path. This apparatus has several advantages over the conventional shuttlebox: (1)There is little constraint on the direction of swimming; (2) the magnitude of response (swimming distance) required for avoidance can easily be varied over a wide range; and (3) variation in the effectiveness of shock with the position of the animal relative to the position of the electrodes is minimized. Some sample data obtained in a …

Can ultraviolet cues function as aposematic signals?

2001

The fact that birds are sensitive to ultraviolet light (UV, 320–400 nm) has been largely ignored by previous studies of aposematism. Therefore, in the present article we investigated whether great tits preferred ultraviolet-reflecting colors compared to colors without UV reflection and whether UV cues alone could function as aposematic signals. We were able to manipulate prey visibility in UV light by changing the UV reflectance of prey items as well as altering the lighting conditions. In order to perform a preference experiment we used three pairs of colors (green UV vs. green, gray UV vs. gray, yellow UV vs. yellow) on a black background. The birds ate both UV types equally for all three…

Enable concurrent transmissions with beamforming for broadband wireless access in CSMA/CA-based WLANs

2014

In CSMA/CA based wireless local networks, two stations are not allowed to transmit at the same time due to interference generated to each other, resulting in degraded throughput. Concurrent transmission, which enables simultaneous transmission of two or more stations under certain conditions, is able to overcome this problem, leading to enhanced channel utilization efficiency. Different from earlier work on this topic which focuses on omni-direction concurrent transmission, we introduce in this paper beamforming into a co-channel concurrent transmission scheme and investigate the benefits of concurrency with beamforming. The circumstances for concurrent transmission and frame scheduling are…

Avoidance of Cu- and Zn-contaminated soil by three ecologically different earthworm species

2005

Earthworm avoidance response to soils contaminated with harmful substances has been proposed as a potential tool for assessing soil toxicity with low test effort. In the present study, the objective was to find out whether three ecologically different earthworm species, Aporrectodea tuberculata (Eisen), Lumbricus rubellus (Hoffmeister), and Dendrobaena octaedra (Savigny), avoid soils simultaneously spiked with Cu and Zn. In addition, metal-contaminated field soil taken close to a Cu-Ni smelter was tested with A. tuberculata using a two-section avoidance lest procedure. All three earthworm species clearly avoided Cu/Zn contaminated soil but differently: D. octaedra was the most sensitive spe…

Predictors of Psychological Distress and Coronavirus Fears in the First Recovery Phase of the Coronavirus Disease 2019 Pandemic in Germany

2021

Objectives: While previous research has mainly focused on the impact of the first acute phase of the COVID-19 pandemic on mental health, little empirical knowledge exists about depression, anxiety, and somatic symptom levels and possible predictors of symptom levels in the pandemic’s recovery phase. The present study aimed to analyze the mental burden of a convenience ample of the general German population during the first recovery phase of the pandemic and to identify significant predictors of symptom levels.Methods: Standardized measures of anxiety (GAD-2), depression (PHQ-2), somatic symptoms (PHQ-15), and health anxiety, as well as measures of COVID-19 fears and possible vulnerability f…

The angiopoietin-Tie2 pathway regulates Purkinje cell dendritic morphogenesis in a cell-autonomous manner.

2021

Neuro-vascular communication is essential to synchronize central nervous system development. Here, we identify angiopoietin/Tie2 as a neuro-vascular signaling axis involved in regulating dendritic morphogenesis of Purkinje cells (PCs). We show that in the developing cerebellum Tie2 expression is not restricted to blood vessels, but it is also present in PCs. Its ligands angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) are expressed in neural cells and endothelial cells (ECs), respectively. PC-specific deletion of Tie2 results in reduced dendritic arborization, which is recapitulated in neural-specific Ang1-knockout and Ang2 full-knockout mice. Mechanistically, RNA sequencing reveals that Tie…

Virtual reality in the treatment of claustrophobic fear: A controlled, multiple-baseline design

2000

The aim of this study was to determine the effectiveness of virtual reality (VR) exposure in the treatment of claustrophobic fear. We evaluated the intervention following a controlled, multiple-baseline design across 4 participants with claustrophobic fear who sought psychological help in our anxiety disorders clinic. The treatment consisted of 8 individual VR graded exposure sessions. Data were obtained at pretreatment, posttreatment, and 3-month follow-up on several clinical measures: Behavioral Avoidance Test, Self-Efficacy Toward Closed Spaces, Problem-Related Impairment Questionnaire, Beck Depression Inventory (Beck, 1978), and Anxiety Sensitivity Index (Peterson & Reiss, 1992). Result…

Collision Avoidance Problem for an Ekranoplan

2008

Fuzzy-logic-based approach for identifying objects of interest in the PRIDE framework

2008

On-road autonomous vehicle navigation requires real-time motion planning in the presence of static and moving objects. Based on sensed data of the environment and the current traffic situation, an autonomous vehicle has to plan a path by predicting the future location of objects of interest. In this context, an object of interest is a moving or stationary object in the environment that has a reasonable probability of intersecting the path of the autonomous vehicle within a predetermined time frame. This paper investigates the identification of objects of interest within the PRIDE (PRediction In Dynamic Environments) framework. PRIDE is a multi-resolutional, hierarchical framework that predi…

Partisanship, Ideology, and Selective Exposure: A Longitudinal Analysis of Media Consumption in Spain (2008–2019)

2022

La literatura sobre exposición selectiva ha demostrado que la ideología y el voto gobiernan las decisiones de consumo de medios, pero los estudios longitudinales aún son escasos. Para llenar este vacío, este trabajo analiza: (a) si la exposición selectiva guiada por la ideología y el partidismo a tres tipos de medios (televisión, radio y periódicos) es un fenómeno estable en España (2008-2019) como se espera de un medio pluralista polarizado. sistema; y (b) qué variable tiene los efectos más fuertes en las elecciones de noticias (ideología o partidismo). Se realizan regresiones logísticas multinomiales utilizando fuentes de datos de seis encuestas postelectorales realizadas por el Centro de…