Straight Lines, ‘Uncurved Lines’, and Helmholtz's ‘Great Circles on the Celestial Sphere’

Perception ◽  
10.1068/p5652 ◽  
2007 ◽  
Vol 36 (9) ◽  
pp. 1275-1289 ◽  
Author(s):  
Brian Rogers ◽  
Kenneth Brecher
Keyword(s):  
Visual System ◽  
Visual Space ◽  
Listing's Law ◽  
Lack Of Information ◽  
Listing’S Law ◽  
The World ◽  
Celestial Sphere ◽  
Straight Lines ◽  
Different Parts

Helmholtz's famous pincushioned chessboard figure has been used to make the point that straight lines in the world are not always perceived as straight and, conversely, that curved lines in the world can sometimes be seen as straight. However, there is little agreement as to the cause of these perceptual errors. Some authors have attributed the errors to the shape of the retina, or the amount of cortex devoted to the processing of images falling on different parts of the retina, while others have taken the effects to indicate that visual space itself is curved. Helmholtz himself claimed that the ‘uncurved lines on the visual globe’ corresponded to ‘direction circles’ defined as those arcs described by the line of fixation when the eye moves according to Listing's law. Careful re-reading of Helmholtz together with some additional observations lead us to the conclusion that two other factors are also involved in the effect: (i) a lack of information about the distance of peripherally viewed objects and (ii) the preference of the visual system for seeing the pincushion squares as similar in size.

scholarly journals V1 neurons encode the perceptual compensation of “false torsion” arising from Listing’s law

2018 ◽  
Author(s):  
Mohammad Farhan Khazali ◽  
Peter Thier
Keyword(s):  
Eye Movements ◽  
Visual System ◽  
Eye Position ◽  
V1 Neurons ◽  
Listing's Law ◽  
Listing’S Law ◽  
Torsional Component

AbstractWe try to deploy the retinal fovea to optimally scrutinize an object of interest by directing our eyes to it. Horizontal and vertical components of these fixation eye movements are determined by the object’s location. However, fixation eye movements also involve a torsional component, which according to Listing’s law is fully determined by the 2D eye position acquired. According to Von Helmholtz knowledge of the torsion provided by this law alleviates the perceptual interpretation of the image tilt that changes with fixation, a view supported by psychophysical experiments he pioneered. We address the question where and how Listing’s law is implemented in the visual system and we show that neurons in monkey area V1 use knowledge of torsion to compensate the image tilt associated with specific eye positions as set by Listing’s law.

scholarly journals V1 neurons encode the perceptual compensation of false torsion arising from Listing’s law

2020 ◽  
Vol 117 (31) ◽  
pp. 18799-18809
Author(s):  
Mohammad Farhan Khazali ◽  
Hamidreza Ramezanpour ◽  
Peter Thier
Keyword(s):  
Visual System ◽  
Eye Position ◽  
Two Dimensional ◽  
V1 Neurons ◽  
Listing's Law ◽  
Listing’S Law ◽  
Torsional Component ◽  
Eye Torsion

We try to deploy the retinal fovea to optimally scrutinize an object of interest by directing our eyes to it. The horizontal and vertical components of eye positions acquired by goal-directed saccades are determined by the object’s location. However, the eccentric eye positions also involve a torsional component, which according to Donder’s law is fully determined by the two-dimensional (2D) eye position acquired. According to von Helmholtz, knowledge of the amount of torsion provided by Listing’s law, an extension of Donder’s law, alleviates the perceptual interpretation of the image tilt that changes with 2D eye position, a view supported by psychophysical experiments he pioneered. We address the question of where and how Listing’s law is implemented in the visual system and we show that neurons in monkey area V1 use knowledge of eye torsion to compensate the image tilt associated with specific eye positions as set by Listing’s law.

BIOASSAY CHARACTERISTICS OF INDIVIDUAL URINARY GONADOTROPHIN EXTRACTS

1963 ◽  
Vol 42 (2) ◽  
pp. 214-224
Author(s):  
Raymond C. Mellinger ◽  
Jalileh A. Mansour ◽  
Richmond W. Smith
Keyword(s):  
Reference Material ◽  
Young Women ◽  
Reference Standard ◽  
General Acceptance ◽  
Modifying Factors ◽  
Large Numbers ◽  
The World ◽  
Quantitative Bioassay ◽  
Different Parts ◽  
Age And Sex

ABSTRACT A reference standard is widely sought for use in the quantitative bioassay of pituitary gonadotrophin recovered from urine. The biologic similarity of pooled urinary extracts obtained from large numbers of subjects, utilizing groups of different age and sex, preparing and assaying the materials by varying techniques in different parts of the world, has lead to a general acceptance of such preparations as international gonadotrophin reference standards. In the present study, however, the extract of pooled urine from a small number of young women is shown to produce a significantly different bioassay response from that of the reference materials. Gonadotrophins of individual subjects likewise varied from the multiple subject standards in many instances. The cause of these differences is thought to be due to the modifying influence of non-hormonal substances extracted from urine with the gonadotrophin and not necessarily to variations in the gonadotrophins themselves. Such modifying factors might have similar effects in a comparative assay of pooled extracts contributed by many subjects, but produce significant variations when material from individual subjects is compared. It is concluded that the expression of potency of a gonadotrophic extract in terms of pooled reference material to which it is not essentially similar may diminish rather than enhance the validity of the assay.

Christianity in the Twentieth Century

2019 ◽  
Author(s):  
Brian Stanley
Keyword(s):  
Latin America ◽  
Racial Identity ◽  
Sub Saharan Africa ◽  
Central Importance ◽  
Regional Survey ◽  
History Of Christianity ◽  
The World ◽  
History Of ◽  
Sub Saharan ◽  
Different Parts

This book charts the transformation of one of the world's great religions during an age marked by world wars, genocide, nationalism, decolonization, and powerful ideological currents, many of them hostile to Christianity. The book traces how Christianity evolved from a religion defined by the culture and politics of Europe to the expanding polycentric and multicultural faith it is today—one whose growing popular support is strongest in sub-Saharan Africa, Latin America, China, and other parts of Asia. The book sheds critical light on themes of central importance for understanding the global contours of modern Christianity, illustrating each one with contrasting case studies, usually taken from different parts of the world. Unlike other books on world Christianity, this one is not a regional survey or chronological narrative, nor does it focus on theology or ecclesiastical institutions. The book provides a history of Christianity as a popular faith experienced and lived by its adherents, telling a compelling and multifaceted story of Christendom's fortunes in Europe, North America, and across the rest of the globe. It demonstrates how Christianity has had less to fear from the onslaughts of secularism than from the readiness of Christians themselves to accommodate their faith to ideologies that privilege racial identity or radical individualism.

THE 2019 NOVEL PANDEMIC OF CORONAVIRUS DISEASE (COVID-19): A STUDY OF EXISTING EVIDENCE IN THE INDIAN POPULATION

2020 ◽  
Vol 7 (2) ◽  
pp. 199-204
Author(s):  
Shrikant Verma ◽  
Mohammad Abbas ◽  
Sushma Verma ◽  
Syed Tasleem Raza ◽  
Farzana Mahdi
Keyword(s):  
Disease Transmission ◽  
Indian Population ◽  
Respiratory Infections ◽  
Clinical Signs ◽  
Case Fatality ◽  
Public Health Emergency ◽  
The World ◽  
And Control ◽  
General Wellbeing ◽  
Different Parts

A novel spillover coronavirus (nCoV), with its epicenter in Wuhan, China's People's Republic, has emerged as an international public health emergency. This began as an outbreak in December 2019, and till November eighth, 2020, there have been 8.5 million affirmed instances of novel Covid disease2019 (COVID-19) in India, with 1,26,611 deaths, resulting in an overall case fatality rate of 1.48 percent. Coronavirus clinical signs are fundamentally the same as those of other respiratory infections. In different parts of the world, the quantity of research center affirmed cases and related passings are rising consistently. The COVID- 19 is an arising pandemic-responsible viral infection. Coronavirus has influenced huge parts of the total populace, which has prompted a global general wellbeing crisis, setting all health associations on high attentive. This review sums up the overall landmass, virology, pathogenesis, the study of disease transmission, clinical introduction, determination, treatment, and control of COVID-19 with the reference to India.

Awareness on Sustainability Perspective among Consumers’ of Tea

2019 ◽  
Vol 118 (7) ◽  
pp. 111-116
Author(s):  
Dr. M. Ayisha Millath ◽  
Dr. K. Malik Ali
Keyword(s):  
Sample Size ◽  
Positive Relationship ◽  
Health Benefits ◽  
High Price ◽  
Educational Qualification ◽  
Lack Of Information ◽  
The World ◽  
Correlation Result ◽  
Day By Day

Tea is an imperative beverage elsewhere in the world.  The need and demand for tea are increasing day by day.  Tea Association of USA expects continued growth in tea sales due to awareness on its health benefits. There are more than 3000 kinds of tea varieties are there but only four varieties are widely used. The authors investigated the opinion on sustainability perspectives and problems faced by them while they intend to buy. Willing Participants are included in survey with the sample size of 237.  The correlation result revealed that there is a positive relationship between educational qualification and sustainability perspectives of tea products among consumers. .  It is also found that lack of information and high price were the major problems faced by tea consumers while intend to buy sustainable tea. So the tea manufacturers and processors must throw light on these issues to improve its preference among consumers.

Jiangnan Style

2017 ◽  
Author(s):  
Chris Wickham
Keyword(s):  
Middle Ages ◽  
Economic Activity ◽  
Global Economy ◽  
Medieval Period ◽  
The World ◽  
Transnational Connections ◽  
New Research ◽  
Different Parts

Building on impressive new research into the concept of a ‘global middle ages’, this chapter offers insights into how economic formations developed around the world. Drawing on new research on both Chinese and Mediterranean economies in the ‘medieval’ period, it compares structures of economy and exchange in very different parts of the world. The point of such comparisons is not simply to find instances of global economic flows but to understand the logic of medieval economic activity and its intersections with power and culture; and, in so doing, to remind historians that economic structures, transnational connections, and the imbrications of economy and politics do not arrive only with modernity, nor is the shape of the ‘modern’ global economy the only pattern known to humankind.

The Struggle for Public Recognition: Understanding Early Marriage through the Lens of Honour and Shame in Six Countries in South Asia and West Africa

2020 ◽  
Vol 20 (4) ◽  
pp. 328-346
Author(s):  
Esther Miedema ◽  
Winny Koster ◽  
Nicky Pouw ◽  
Philippe Meyer ◽  
Albena Sotirova
Keyword(s):  
International Development ◽  
Female Sexuality ◽  
Social Economic ◽  
Early Marriage ◽  
Social Standing ◽  
Public Recognition ◽  
The World ◽  
Economic Future ◽  
Different Parts

There is a burgeoning body of research on the role of ‘shame’ and ‘honour’ in decisions regarding early marriage in different parts of the world. Conceptualizing shame and honour as idioms through which gendered socio-economic inequalities are created and maintained, we examine early marriage decisions in Bangladesh, Nepal, Pakistan, Ghana, Burkina Faso and Senegal. While we acknowledge the existence of important differences between countries in terms of the nature and manifestations of shame and honour, we argue that regardless of setting, neither shame and honour, nor female sexuality and chastity can be separated from the socio-economic hierarchies and inequalities. Thus, in this article we seek to identify the cross-cutting dynamic of marriage as a means to overcome the shame associated with young single women’s sexuality, protecting family honour and social standing, and/or securing young women’s social-economic future. Building on our data and available scholarship, we question the potential of emphasizing ‘choice’ as a means of reducing early marriage and advancing women’s emancipation in international development efforts. Instead, we argue in favour of initiatives that engage with young people and caregivers on the ways in which, at grassroot levels, communities may revise narratives of respectability, marriageability and social standing.

scholarly journals Epigenetic polymorphism in wild populations of Mus musculus

1963 ◽  
Vol 4 (2) ◽  
pp. 193-220 ◽  
Author(s):  
R. J. Berry
Keyword(s):  
House Mouse ◽  
Mus Musculus ◽  
Stabilizing Selection ◽  
British Isles ◽  
Wild Populations ◽  
Local Populations ◽  
The World ◽  
Different Populations ◽  
Different Parts

It has been suggested (Berry & Searle, 1963) that the discontinuous (‘quasi-continuous’) variants studied by Grüneberg et al. in the skeleton of rodents can be regarded as constituting epigenetic polymorphism in different populations. Comparisons have been made between the incidences of skeletal variants in house mouse populations collected from: corn ricks on a single farm in Hampshire; eleven separated localities in different parts of the British Isles; and nine other places throughout the world. These showed that the method could profitably be used for genetically characterizing and hence comparing populations. There was evidence suggestive of genetical drift between local populations and stabilizing selection over a larger area.

scholarly journals Imaginative geography, neoliberal globalization, and colonial distinctions: docile and dangerous bodies in medical transcription ‘outsourcing’

2012 ◽  
Vol 19 (3) ◽  
pp. 349-364 ◽  
Author(s):  
Amit Prasad ◽  
Srirupa Prasad
Keyword(s):  
The United States ◽  
It Outsourcing ◽  
Neoliberal Globalization ◽  
Global Citizens ◽  
The World ◽  
Imaginative Geography ◽  
Transnational Space ◽  
Transnational Activities ◽  
Discursive Constructions ◽  
Different Parts

Information Technology (IT) ‘outsourcing,’ of which medical transcription in India is a part, has received relatively little attention from geographers. Most often, it has been bracketed more broadly within IT and its role in transforming transnational space-time configurations has been analyzed. IT outsourcing, more specifically, medical transcription outsourcing, which is the focus of this article, is not only marked by tensions, hierarchies, and ambivalences, it also reflects an emergent ‘imaginative geography’ of neoliberal globalization. This imaginative geography, as we argue in this article, is deceptively ambiguous because of its ambivalent articulation. Medical transcription outsourcing, for example, seems to operate on two contradictory registers, particularly in the United States and some European nations from where outsourcing to countries such as India is taking place. There is an acknowledgement and even celebration of the ‘flattening’ and inter-connectedness of different parts of the world, even while there is widespread criticism and fear of these transnational activities, as well as that of the non-western people engaged in them. The criticism and fear are often articulated in relation to instances of data theft. Nevertheless, a closer look shows that there is something more going on. We argue that such discursive constructions exemplify an imaginative geography that is rooted in an ambivalent desire for a reformed and recognizable ‘other’ who could be ‘best global citizens.’ This ambivalence undergirds a forked biopolitical strategy, which seeks to make the neoliberal worker docile and yet continually marks him/her as dangerous. We call this biopolitical strategy colonial governmentality to signify its forked operation as an art of government that seeks to define agenda/non-agenda (and not population or people), but continually draws upon colonial distinctions and practices.

Sign in / Sign up

Export Citation Format

Share Document