Preference of pigs for illuminance

2003 ◽  
Vol 2003 ◽  
pp. 38-38
Author(s):  
N.R. Taylor ◽  
G. Perry ◽  
M. Potter ◽  
N.B. Prescott ◽  
C.M. Wathes
Keyword(s):  
Visual System ◽  
Wild Boar ◽  
Activity Patterns ◽  
Artificial Lighting ◽  
Light Levels ◽  
Wide Range

Pigs housed under artificial lighting currently experience a wide range of illuminances and photoperiods, which may be more appropriate to the visual capabilities and needs of stockpersons rather than pigs. Pigs and wild boar can show nocturnal, diurnal and crepuscular activity patterns, suggesting that their visual system may function well under a wide range of light levels, unlike humans. Inappropriate lighting affects many aspects of an animal’s physiology, anatomy and behaviour and may compromise welfare. This experiment was designed to investigate the preference of juvenile pigs to occupy and conduct certain behaviours in different illuminances, and gain some indication of their preferred photoperiod.

Foraging ecology of the night-active bull ant Myrmecia pyriformis

2013 ◽  
Vol 61 (2) ◽  
pp. 170 ◽  
Author(s):  
Samuel F. Reid ◽  
Ajay Narendra ◽  
Robert W. Taylor ◽  
Jochen Zeil
Keyword(s):  
Visual System ◽  
Foraging Ecology ◽  
Activity Patterns ◽  
Colony Founding ◽  
Liquid Food ◽  
Mating Season ◽  
Wild Populations ◽  
Ecological Information ◽  
Light Levels ◽  
Nest Activity

Here we report on the nocturnal bull ant Myrmecia pyriformis, a species whose activity to and from the nest is mainly restricted to the dawn and dusk twilight respectively. Recent research on M. pyriformis has focussed on its visual system, the timing of activity patterns, and the navigational strategies employed by individuals while foraging. There is, however, a lack of basic ecological information about this species. The present study describes the behaviour and foraging ecology of wild populations of M. pyriformis. We find that most foragers make only one foraging journey per night, leaving the nest at dusk twilight and returning during dawn twilight. Individuals who make multiple trips typically return with prey. We provide evidence that foragers imbibe liquid food while abroad and likely share these resources via trophallaxis once within the nest. Activity during the night varies with moon illumination, and we postulate that this is due to changes in light levels, which influence navigation to and from the nest. This hypothesis is supported by observations of activity during overcast conditions. Finally, we also describe some aspects of colony founding, colony demise and the behaviour of reproductive individuals during the mating season.

scholarly journals Early Dropout Prediction in MOOCs through Supervised Learning and Hyperparameter Optimization

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1701
Author(s):  
Theodor Panagiotakopoulos ◽  
Sotiris Kotsiantis ◽  
Georgios Kostopoulos ◽  
Omiros Iatrellis ◽  
Achilles Kameas
Keyword(s):  
Online Education ◽  
Online Courses ◽  
Early Stage ◽  
Activity Patterns ◽  
Daily Basis ◽  
Machine Learning Algorithms ◽  
Supervised Machine Learning ◽  
Educational Institutions ◽  
Student Dropout ◽  
Wide Range

Over recent years, massive open online courses (MOOCs) have gained increasing popularity in the field of online education. Students with different needs and learning specificities are able to attend a wide range of specialized online courses offered by universities and educational institutions. As a result, large amounts of data regarding students’ demographic characteristics, activity patterns, and learning performances are generated and stored in institutional repositories on a daily basis. Unfortunately, a key issue in MOOCs is low completion rates, which directly affect student success. Therefore, it is of utmost importance for educational institutions and faculty members to find more effective practices and reduce non-completer ratios. In this context, the main purpose of the present study is to employ a plethora of state-of-the-art supervised machine learning algorithms for predicting student dropout in a MOOC for smart city professionals at an early stage. The experimental results show that accuracy exceeds 96% based on data collected during the first week of the course, thus enabling effective intervention strategies and support actions.

The sleep maths: A strong correlation between more daytime light and better night-time sleep

2021 ◽  
Vol 53 (5) ◽  
pp. 423-435
Author(s):  
MG Figueiro ◽  
C Jarboe ◽  
L Sahin
Keyword(s):  
Sleep Quality ◽  
Visual System ◽  
Psychological Health ◽  
Strong Correlation ◽  
Emotional Health ◽  
Circadian System ◽  
The Self ◽  
Night Time ◽  
Online Surveys ◽  
Light Levels

Lighting for workplaces and schools is typically specified to meet the needs of the visual system without sufficient regard to the lighting characteristics that are required by the human circadian system. In 2020, many workers and students were compelled by the COVID-19 pandemic to work and study from home, where light levels are typically even lower than those found in most schools and workplaces. Using online surveys, this study sought to quantify potential changes in daytime light exposures resulting from teleworking or self-isolating at home and how those changes might have affected self-reported sleep quality, psychological health and emotional health. The first survey was administered in early May 2020, and the second survey was administered in September 2020. In broad terms, our analysis indicates that the greater the amount of light one is exposed to during the day (either in the home or outdoors), the better the self-reported sleep outcomes. Stress and mood were also correlated with greater self-reported daytime light exposures. The results suggest that spending one to two hours outdoors or staying in a bright to very bright room indoors may improve night-time sleep. These results have important implications for daytime lighting in homes, offices and schools.

The C-start escape response ofPolypterus senegalus: bilateral muscle activity and variation during stage 1 and 2

2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
High Speed ◽  
Wave Speed ◽  
Activity Patterns ◽  
Motor Pattern ◽  
The Body ◽  
Wide Range ◽  
Fast Start ◽  
Stage 1

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.

scholarly journals Harmonic Brain Modes: A Unifying Framework for Linking Space and Time in Brain Dynamics

2017 ◽  
Vol 24 (3) ◽  
pp. 277-293 ◽  
Author(s):  
Selen Atasoy ◽  
Gustavo Deco ◽  
Morten L. Kringelbach ◽  
Joel Pearson
Keyword(s):  
Neural Activity ◽  
Brain Activity ◽  
Activity Patterns ◽  
Structural Connectivity ◽  
Building Blocks ◽  
Mental States ◽  
Brain Dynamics ◽  
Space And Time ◽  
Wide Range ◽  
The Brain

A fundamental characteristic of spontaneous brain activity is coherent oscillations covering a wide range of frequencies. Interestingly, these temporal oscillations are highly correlated among spatially distributed cortical areas forming structured correlation patterns known as the resting state networks, although the brain is never truly at “rest.” Here, we introduce the concept of harmonic brain modes—fundamental building blocks of complex spatiotemporal patterns of neural activity. We define these elementary harmonic brain modes as harmonic modes of structural connectivity; that is, connectome harmonics, yielding fully synchronous neural activity patterns with different frequency oscillations emerging on and constrained by the particular structure of the brain. Hence, this particular definition implicitly links the hitherto poorly understood dimensions of space and time in brain dynamics and its underlying anatomy. Further we show how harmonic brain modes can explain the relationship between neurophysiological, temporal, and network-level changes in the brain across different mental states ( wakefulness, sleep, anesthesia, psychedelic). Notably, when decoded as activation of connectome harmonics, spatial and temporal characteristics of neural activity naturally emerge from the interplay between excitation and inhibition and this critical relation fits the spatial, temporal, and neurophysiological changes associated with different mental states. Thus, the introduced framework of harmonic brain modes not only establishes a relation between the spatial structure of correlation patterns and temporal oscillations (linking space and time in brain dynamics), but also enables a new dimension of tools for understanding fundamental principles underlying brain dynamics in different states of consciousness.

scholarly journals Transformation from independent to integrative coding of multi-object arrangements in human visual cortex

2017 ◽  
Author(s):  
Daniel Kaiser ◽  
Marius V. Peelen
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Activity Patterns ◽  
Spatial Arrangement ◽  
Living Room ◽  
Natural Scenes ◽  
Response Patterns ◽  
Object Representations ◽  
Individual Object ◽  
Object Coding

AbstractTo optimize processing, the human visual system utilizes regularities present in naturalistic visual input. One of these regularities is the relative position of objects in a scene (e.g., a sofa in front of a television), with behavioral research showing that regularly positioned objects are easier to perceive and to remember. Here we use fMRI to test how positional regularities are encoded in the visual system. Participants viewed pairs of objects that formed minimalistic two-object scenes (e.g., a “living room” consisting of a sofa and television) presented in their regularly experienced spatial arrangement or in an irregular arrangement (with interchanged positions). Additionally, single objects were presented centrally and in isolation. Multi-voxel activity patterns evoked by the object pairs were modeled as the average of the response patterns evoked by the two single objects forming the pair. In two experiments, this approximation in object-selective cortex was significantly less accurate for the regularly than the irregularly positioned pairs, indicating integration of individual object representations. More detailed analysis revealed a transition from independent to integrative coding along the posterior-anterior axis of the visual cortex, with the independent component (but not the integrative component) being almost perfectly predicted by object selectivity across the visual hierarchy. These results reveal a transitional stage between individual object and multi-object coding in visual cortex, providing a possible neural correlate of efficient processing of regularly positioned objects in natural scenes.

scholarly journals Unique spatial integration in mouse primary visual cortex and higher visual areas

2019 ◽  
Author(s):  
Kevin A. Murgas ◽  
Ashley M. Wilson ◽  
Valerie Michael ◽  
Lindsey L. Glickfeld
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Spatial Information ◽  
Spatial Scales ◽  
Spatial Integration ◽  
Global Features ◽  
Wide Range ◽  
Visual Areas ◽  
Higher Visual Areas

AbstractNeurons in the visual system integrate over a wide range of spatial scales. This diversity is thought to enable both local and global computations. To understand how spatial information is encoded across the mouse visual system, we use two-photon imaging to measure receptive fields in primary visual cortex (V1) and three downstream higher visual areas (HVAs): LM (lateromedial), AL (anterolateral) and PM (posteromedial). We find significantly larger receptive field sizes and less surround suppression in PM than in V1 or the other HVAs. Unlike other visual features studied in this system, specialization of spatial integration in PM cannot be explained by specific projections from V1 to the HVAs. Instead, our data suggests that distinct connectivity within PM may support the area’s unique ability to encode global features of the visual scene, whereas V1, LM and AL may be more specialized for processing local features.

Abstract P274: Physical Activity Patterns and Determinants Following Acute Myocardial Infarction: Insights From the VIRGO Study (Variation in Recovery: Role of Gender on Outcomes of Young Acute Myocardial Infarction Patients)

Circulation ◽  
2015 ◽  
Vol 131 (suppl_1) ◽  
Author(s):  
Karl E Minges ◽  
Kelly M Strait ◽  
Sarah Camhi ◽  
Judith H Lichtman ◽  
Rachel P Dreyer ◽  
...  
Keyword(s):  
Physical Activity ◽  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Activity Patterns ◽  
Estimating Equation ◽  
Vigorous Activity ◽  
Targeted Interventions ◽  
Factors Associated ◽  
Wide Range ◽  
Over Time

Introduction: Despite the benefits of participation in regular physical activity (PA) following acute myocardial infarction (AMI), little is known about the habitual patterns of PA for young AMI patients, especially expanding beyond findings for those engaged in cardiac rehabilitation. We assessed patterns and determinants in levels of PA over a period of 12-months following AMI. Methods: A 2:1 (women:men) observational study design enrolled 3,572 AMI patients (2,397 women, 67.1%) aged 18-55 years from 103 US, 24 Spanish, and 3 Australian hospitals (2008-2012). Data were obtained by medical record abstraction and patient interviews at baseline (pre-AMI), 1- and 12-months post-AMI. Patients were assigned to AHA defined levels of PA based on self-reported frequency, duration, and intensity, as follows: Active (≥ 150 min/wk moderate or ≥ 75 min/wk vigorous activity), Insufficient (10-149 min/wk moderate or 10-74 min/wk vigorous activity), or Inactive (< 10 min/wk moderate or vigorous activity). We used a generalized estimating equation model to examine the factors associated with insufficient/inactive PA levels over time. Results: At baseline, 1- and 12-months post-AMI, 36.7%, 37.6%, and 40.0% of patients were considered active. There were 27 PA patterns observed from baseline to 12-months (Table). The most frequent were those with no change in PA over time (14% staying active, 7% insufficient, and 13% inactive). Additionally, 25% of patients had an increase (at least a one category change) in PA, while 19% had a decrease between baseline and 12-months post-AMI. Female sex, non-white race, non-active workplaces, smoking, diabetes, hypertension, and obesity were independently associated with being insufficient/inactive over time (all p<.05). Conclusions: Despite clinical recommendations, young adults recovering from AMI experience a wide range of PA patterns. By identifying factors associated with insufficient/inactive PA during recovery, targeted interventions can be introduced prior to hospital discharge.

Surface activity patterns of macrofauna on pocket, tidal beaches: Insights into the role of wrack and artificial lighting

2016 ◽  
Vol 7 ◽  
pp. 63-71 ◽  
Author(s):  
Lucia Fanini ◽  
Lauren E. Hughes ◽  
Roger Springthorpe ◽  
Louise Tosetto ◽  
Jim K. Lowry
Keyword(s):  
Surface Activity ◽  
Activity Patterns ◽  
Artificial Lighting

scholarly journals The color of night: Surface color categorization by color defective observers under dim illuminations

2008 ◽  
Vol 25 (3) ◽  
pp. 475-480 ◽  
Author(s):  
JOEL POKORNY ◽  
MARGARET LUTZE ◽  
DINGCAI CAO ◽  
ANDREW J. ZELE
Keyword(s):  
Color Vision ◽  
Surface Color ◽  
Low Light ◽  
Light Levels ◽  
Color Categories ◽  
Wide Range ◽  
Basic Color ◽  
Color Vision Deficiencies ◽  
Orange Color ◽  
Color Scales

People with normal trichromatic color vision experience variegated hue percepts under dim illuminations where only rod photoreceptors mediate vision. Here, hue perceptions were determined for persons with congenital color vision deficiencies over a wide range of light levels, including very low light levels where rods alone mediate vision. Deuteranomalous trichromats, deuteranopes and protanopes served as observers. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10 to 0.0003 Lux (1.0 to −3.5 log Lux). Triads of samples were chosen representing each of eight basic color categories; “red,” “pink,” “orange,” “yellow,” “green,” “blue,” “purple,” and “gray.” Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above −0.5 log Lux, the dichromatic and anomalous trichromatic observers sorted the samples into the original representative color groups, with some exceptions. At light levels where rods alone mediate vision, the color names assigned by the deuteranomalous trichromats were similar to the color names used by color normals; higher scotopic reflectance samples were classified as blue-green-grey and lower reflectance samples as red-orange. Color names reported by the dichromats at the dimmest light levels had extensive overlap in their sample scotopic lightness distributions. Dichromats did not assign scotopic color names based on the sample scotopic lightness, as did deuteranomalous trichromats and colour-normals. We reasoned that the reduction in color gamut that a dichromat experiences at photopic light levels leads to a limited association of rod color perception with objects differing in scotopic reflectance.

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