Vision

2017 ◽  
Author(s):  
Graham R. Martin
Keyword(s):  
Natural Selection ◽  
Contrast Sensitivity ◽  
Spatial Resolution ◽  
Colour Vision ◽  
World View ◽  
Visual Fields ◽  
Primary Source ◽  
Absolute Sensitivity ◽  
Trade Offs ◽  
Source Of Information

Vision is the primary source of information about the environments in which birds live. But vision is not ‘all-seeing’; it is subject to many constraints, trade-offs, and compromises. Furthermore, the basic components of eyes (optics, image analysing systems, and eye positions) have been subject to intense and persistent natural selection which has resulted in eyes whose capacities are tuned in many and subtle ways to the perceptual challenges posed by life in different environments. Colour vision, spatial resolution, contrast sensitivity, absolute sensitivity, and visual fields all differ markedly between species. Even two birds with eyes that appear very similar may have quite different bird’s eye views, and all birds have a different world view from our own. Knowledge of these differences is vital for understanding the behaviours of birds. While vision provides key information only rarely is it sufficient to guide behaviour, information from other senses must come into play.

scholarly journals High resolution of colour vision, but low contrast sensitivity in a diurnal raptor

2018 ◽  
Vol 285 (1885) ◽  
pp. 20181036 ◽  
Author(s):  
Simon Potier ◽  
Mindaugas Mitkus ◽  
Almut Kelber
Keyword(s):  
High Resolution ◽  
Contrast Sensitivity ◽  
Spatial Resolution ◽  
Colour Vision ◽  
Bird Species ◽  
Resolving Power ◽  
Low Contrast ◽  
Achromatic Contrast ◽  
Parabuteo Unicinctus ◽  
Chromatic Sensitivity

Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the achromatic contrast sensitivity function and (ii) the spatial resolution of the chromatic channel of a diurnal raptor, the Harris's hawk Parabuteo unicinctus . The maximal spatial resolution for achromatic gratings was 62.3 c deg −1 , but the contrast sensitivity was relatively low (10.8–12.7). The spatial resolution for isoluminant red-green gratings was 21.6 c deg −1 —lower than that of the achromatic channel, but the highest found in the animal kingdom to date. Our study reveals that Harris's hawks have high spatial resolving power for both achromatic and chromatic vision, suggesting the importance of colour vision for foraging. By contrast, similar to other bird species, Harris's hawks have low contrast sensitivity possibly suggesting a trade-off with chromatic sensitivity. The result is interesting in the light of the recent finding that double cones—thought to mediate high-resolution vision in birds—are absent in the central fovea of raptors.

Nutrient supplementation among pregnant women in China: an observational study

2021 ◽  
pp. 1-19
Author(s):  
Tao Han ◽  
Jingwen Dong ◽  
Jiangtao Zhang ◽  
Chenxiao Zhang ◽  
Yuxuan Wang ◽  
...  
Keyword(s):  
Vitamin D ◽  
Folic Acid ◽  
Pregnant Women ◽  
Family Members ◽  
Primary Source ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Nutrient Supplementation ◽  
Face To Face ◽  
Source Of Information

Abstract Objective: To clarify nutrient supplementation usage and primary source of information among pregnant women in China. Design: This cross-sectional study used information on nutrient supplementation and primary source of information collected via face-to-face interviews. Data on the usage of folic acid, calcium/vitamin D, iron, vitamins, docosahexaenoic acid, and other dietary supplements were collected. Primary source of information were categorized as family/relatives, friends/co-workers, the Internet, books/magazines, television/radio, doctors, other people, and oneself. Setting: Maternal and Child Health Hospital in Chengdu, China. Participants: 1081 Chinese pregnant women aged ≥ 20 years with singleton pregnancies. Results: In all three trimesters of pregnancy, usage was highest and most stable for folic acid (81.7%), followed by vitamins (vitamin A, B-group vitamins, vitamin C, and multivitamins; 75.0%), whereas calcium/vitamin D (51.4%) and iron (18.1%) usage was low, potentially indicating a deficiency risk. All supplementation usage percentages increased with pregnancy duration (p < 0.05). Notably, approximately 10% of the pregnant women in our study did not use any nutrient supplementation, and this was especially common in early pregnancy. More than 50% of the women reported getting information on nutrient supplementation from family members, and about 30% reported getting this information from doctors. Conclusions: Among pregnant women in China, awareness about nutrient supplementation increases as the pregnancy progresses, but some types of nutrient supplementation (such as calcium/vitamin D and iron) remain at low levels. It is necessary to pay more attention to the health education of pregnant women in China, and the influence of family members should be emphasized.

The Beloved Disciple, the Fourth Evangelist, and the Authorship of the Fourth Gospel

2018 ◽  
Author(s):  
Tom Thatcher
Keyword(s):  
Social Science ◽  
Gospel Of John ◽  
Primary Source ◽  
Fourth Gospel ◽  
The Past ◽  
Historical Individual ◽  
Source Of Information ◽  
Beloved Disciple

Discussions of the authorship of the Gospel of John must answer two questions: who is the Beloved Disciple who is portrayed as the book’s primary source of information, and how is this individual related to the author, John the evangelist? On the first question, scholars are divided on whether the Beloved Disciple is a real historical individual or an ideal symbolic figure. Data from the text itself and from social-science perspectives on the reputations of key figures from the past suggest that both are correct: the Beloved Disciple was a legendary associate of Jesus whose presentation reflects his reputation as a source of information that was critical to the Johannine theological outlook. On the second question, data suggests that the evangelist was not the Beloved Disciple but rather a disciple of that individual, perhaps basing his own book on an earlier document produced by the Beloved Disciple.

Effects of strabismus on responsivity, spatial resolution, and contrast sensitivity of cat lateral geniculate neurons

1984 ◽  
Vol 52 (3) ◽  
pp. 538-552 ◽  
Author(s):  
K. R. Jones ◽  
R. E. Kalil ◽  
P. D. Spear
Keyword(s):  
Contrast Sensitivity ◽  
Spatial Resolution ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Orienting Response ◽  
Lateral Geniculate ◽  
Spatial Frequencies ◽  
Area Centralis ◽  
X Cells ◽  
Y Cells

Rearing cats with esotropia is known to cause a number of deficits in visual behavior tested through the deviated eye. These include a loss of orienting response to stimuli presented in the nasal visual field of the deviated eye, a reduction in visual acuity, and a general reduction in contrast sensitivity at all spatial frequencies. To assess the involvement of the lateral geniculate nucleus (LGN) in these deficits, we measured the following: 1) the visual responsiveness of lamina A1 cells with peripheral (more than 10 degrees from area centralis) receptive fields in three esotropic and three normal cats and 2) the spatial resolution and contrast sensitivity of lamina A X-cells with central (within 5 degrees of the area centralis) receptive fields in six esotropic and six normal cats. For comparison, we also measured LGN X-cell spatial resolutions in four exotropic cats and in two cats raised with an esotropia in one eye and the lids of the other eye sutured shut (MD-estropes). Recordings from the lateral portion of lamina A1 in esotropic cats yielded similar numbers of visually responsive cells with far nasal receptive fields as were seen in normal animals. Peak and mean response rates to a flashing spot also were normal. In addition, no differences were found between esotropes and normals in the percentages of X- and Y-cells encountered. These results suggest that the loss of orienting response to stimuli presented in the nasal field (12, 20) is not due to a loss of neural responses in the LGN of esotropic cats. In addition, they suggest that decreases in cell size in lamina A1 of esotropic cats (13, 36; R. E. Kalil, unpublished observations) are not accompanied by marked functional abnormalities of the cells and that cortical abnormalities ipsilateral to the deviated eye (22) are likely to have their origin within striate cortex itself. Recordings from lamina A cells with receptive fields near area centralis revealed that the average X-cell spatial resolution in esotropes (2.1 cycles/deg) was significantly lower than that in normal cats (3.1 cycles/deg). This reduction was seen in all esotropic cats tested and was due both to an increase in the proportion of X-cells with very low spatial resolution and to a loss of X-cells responding to high spatial frequencies (greater than 3.25 cycles/deg). The average spatial resolution of X-cells driven by the deviated eye in MD-esotropes fell midway between those of esotropes and normals. In exotropes, mean X-cell spatial resolution was normal.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Covariance Structure of Compositional Tables

2015 ◽  
Vol 44 (3) ◽  
pp. 31-44 ◽  
Author(s):  
Kamila Fačevicová ◽  
Karel Hron
Keyword(s):  
Odds Ratio ◽  
Covariance Structure ◽  
Primary Source ◽  
Orthonormal Coordinates ◽  
Source Of Information ◽  
Special Case

Recent experiences with interpretation of orthonormal coordinates in compositionaldata show clearly a necessity of their better understanding in terms of logratios that formthe primary source of information within the logratio methodology. This is even morecrucial in the special case of compositional tables, where both balances and coordinateswith odds ratio interpretation are involved. The aim of the paper is to provide a decompo-sition of covariance structure of orthonormal coordinates in compositional tables in termsof logratio variances that could serve for this purpose. For their better interpretability,the formulas are also accompanied with appropriate comments and graphical illustrations,and implications for the prominent case of 2 2 compositional tables are discussed.

Influence of ethnicity, gender, and immigration status on millennials’ behavior related to seeking health information

2018 ◽  
Vol 37 (6) ◽  
pp. 621-631 ◽  
Author(s):  
Roofia Galeshi ◽  
Jyotsna Sharman ◽  
Jinghong Cai
Keyword(s):  
Young Adults ◽  
Information Seeking ◽  
Primary Source ◽  
Immigration Status ◽  
Health Seeking ◽  
Content Type ◽  
Related Information ◽  
Seeking Behavior ◽  
Health Related ◽  
Source Of Information

Purpose The purpose of this paper is to understand the behavior diversities that exist among young millennials’ subgroups in ways they seek health-related information. Design/methodology/approach The authors ran several sets of analyses on the 2012–2014 US Program for the International Assessment of Adult Competencies (PIAAC) Data using Stata. The population was stratified into four specific subgroups based on their gender, ethnicity—blacks, Hispanics and whites—immigration status, college status—whether they were enrolled in a program of study at the time of the survey. The outcome variables were sources of health information including print (books/magazines/brochures), traditional media (Radio/TV), internet, family/friends/co-workers and health professionals. The independent variables were gender, ethnicity, educational status and immigration status. The authors utilized the appropriate sample weight derived by Organization for Economic Cooperation and Development so the findings can be generalized to the populations. The analysis included several descriptive statistics and χ2 test of independence. Findings Despite similarities, young adults’ health seeking behavior is complex influenced by gender, ethnicity, immigration status and education. The results indicated that while the internet is the primary source of health-related information for all young adults, there are subtle differences in utilizing other available resources. For example while more educated young adults seek help from their family members, the less educated peers use the media to obtain health-related information. Ethnicity has also an effect on young adults’ information seeking behavior. The number of Hispanics and blacks that obtain their information from traditional media is significantly higher than their white counterparts. Research limitations/implications This study has several limitations. First, the authors did not consider the effect of young adults’ digital literacy skills, problem solving skills and numeracy skills on their health seeking approach. Including these cognitive skills could reveal key information about young adults approach to information seeking that is not apparent by race, ethnicity and gender only. Another limitation of this study is the lack of the ability to claim causation, PIAAC data are designed strictly for cross-sectional analysis. Practical implications Although, behaviors often do not change simply by presenting information, trying to change behavior without improving individuals’ understanding of the issue by providing accurate information is likely to fail. Providing standardized health-related information sources that are accessible to all is vitally important. The results indicate that while the majority of young adults use the internet as their primary source of information only a few percentage of young adults seek information from health professional. Consequently, there is a need for an easily accessible and standardized online health-related source of information. Social implications Healthcare facilities and health related industries have the resources and the ability to develop a reliable infrastructure that could potentially provide reliable information that is easy to understand and navigate for adults with a variety of literacy and skills to use. Perhaps adopting the Universal Design for Learning approach and providing information that is accessible to a variety of individuals regardless of their education, learning skills and language skills. Flexible learning resources provided within a standard infrastructure accessible to all can help individuals find trustworthy and consistent information that they can trust. Originality/value Despite the unique characteristics of the millennials and the profound change in the way young adults seek information, there is a paucity of research on the ways young adults seek health-related information. Most existing literature is based on locally developed surveys and convenient sampling with limited reliability and validity information. Consequently making a sweeping statement based on their findings is considered as hasty generalization. The PIAAC, on the other hand, is a nationally representative data, extensively examined for its validity and reliability.

Congregations

2011 ◽  
Author(s):  
Mark Chaves
Keyword(s):  
Computer Technology ◽  
Primary Source ◽  
High Income ◽  
American Religion ◽  
Congregational Life ◽  
American Life ◽  
Large Churches ◽  
College Educated ◽  
Source Of Information

This chapter discusses six trends in congregational life: looser connections between congregations and denominations, more computer technology, more informal worship, older congregants, more high-income and college-educated congregants, and, what is perhaps most important, more people concentrated in very large churches. Taken together, these trends show that congregations are shaped by the same cultural, social, and economic pressures affecting American life and institutions more generally. The National Congregations Study (NCS), which began in 1998, is the primary source of information for several of the trends described in this chapter. As with change in American religion as a whole, trends in congregational life should be seen against the backdrop of substantial continuity, especially for the relatively brief period covered by the NCS.

Effect of Temporal Arrangement on Multimedia Learning

2018 ◽  
Author(s):  
Victoria Chen
Keyword(s):  
Prior Knowledge ◽  
Cognitive Processing ◽  
Teaching And Learning ◽  
Multimedia Learning ◽  
Primary Source ◽  
Sources Of Information ◽  
Multimedia Teaching ◽  
Text Information ◽  
Source Of Information

The purpose of this study is to examine whether Multimedia learning theory (Mayer, 1997; Schnotz & Kürschner, 2007) holds true when images are the primary source of information and text information is secondary. I will test how temporal arrangement of audio and image presentations affects quality of learning in this situation. I hypothesize that when audio is played before or after the image participants will require increased cognitive processing to mentally integrate the two sources of information resulting in deeper learning and transfer of learning. On the other hand when audio is played while the image is shown, I hypothesize that participants with high prior knowledge of the subject will score lower than participants with low prior knowledge, because prior knowledge will interfere with knowledge from the two sources causing a redundancy effect. This experiment will lead to greater understanding of multimedia teaching and learning in classrooms as well as how it affects deeper learning.

Ecological immunology

2021 ◽  
pp. 109-142
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Energy Consumption ◽  
Natural Selection ◽  
Ecological Immunology ◽  
Costs And Benefits ◽  
Response Delay ◽  
Genetic Covariance ◽  
Trade Offs ◽  
Immunological Factors ◽  
Immune Defences

Infections and parasite loads vary among hosts. Variation results from ecological, genetic, and immunological factors. Immune defences provide benefits as well as costs and are, therefore, a compromise. Costs result from trade-offs with other needs and can be genetically encoded or plastic (i.e. can change depending on circumstances). Costs are physiological (e.g. energy consumption) or based on evolved genetic covariance. Self-damage (immunopathology) is a further, important cost. Natural selection should optimize the costs and benefits of defences and thus leads to various outcomes in terms of specificity, response delay and strength, or the formation of memory. Moreover, hosts can either resist an infection by eventual clearance, or tolerate the consequences of parasitism.

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