Size and shape of eggs of Neognathae: effects of developmental mode and phylogeny

2017 ◽  
Vol 95 (5) ◽  
pp. 359-366 ◽  
Author(s):  
I.S. Mytiai ◽  
O.V. Shatkovska ◽  
M. Ghazali
Keyword(s):  
Absolute Size ◽  
Phylogenetic Relatedness ◽  
Developmental Mode ◽  
Size And Shape ◽  
Egg Shape ◽  
Lateral Zone ◽  
Shape Indices ◽  
The Absolute ◽  
Pointed End ◽  
Egg Diameter

We evaluated the variation in absolute size and shape of birds’ eggs and the effects of developmental mode and phylogenetic relatedness on these traits. Eggs were characterized by length, diameter, and three indices of egg shape. Indices of egg shape were calculated as the ratio of radii that described the curvature of pointed end (cloacal zone), blunt end (infundibular zone), and lateral zone to egg diameter. We found that eggs shape was less variable than the absolute size of eggs. Index of the cloacal zone was the most changeable and index of the infundibular zone was very conservative. Size and shape of eggs could be better explained with phylogenetic relatedness than developmental mode.

Gravity as a Monocular Cue for Perception of Absolute Distance and/or Absolute Size

Perception ◽  
1992 ◽  
Vol 21 (1) ◽  
pp. 69-76 ◽  
Author(s):  
John S Watson ◽  
Martin S Banks ◽  
Claes von Hofsten ◽  
Constance S Royden
Keyword(s):  
Wave Motion ◽  
Moving Objects ◽  
Formal Analysis ◽  
Free Fall ◽  
Absolute Distance ◽  
Absolute Size ◽  
The Absolute ◽  
Pendulum Wave

When the motion of an object is influenced by gravity (eg free fall, pendulum, wave motion), that influence may provide a cue to computing the absolute distance and/or size of the object. Formal analysis supports the claim that the distance and size of moving objects are generally computable with reference to the gravitational component of motion. Informal evidence from judgments of realism in films is consistent with this gravity-cue hypothesis.

scholarly journals Early and Late Changes in the Distal Forelimb Representation of the Supplementary Motor Area After Injury to Frontal Motor Areas in the Squirrel Monkey

2008 ◽  
Vol 100 (3) ◽  
pp. 1498-1512 ◽  
Author(s):  
Ines Eisner-Janowicz ◽  
Scott Barbay ◽  
Erica Hoover ◽  
Ann M. Stowe ◽  
Shawn B. Frost ◽  
...  
Keyword(s):  
Supplementary Motor Area ◽  
Temporal Dynamics ◽  
Squirrel Monkeys ◽  
Motor Area ◽  
Adaptive Plasticity ◽  
Behavioral Recovery ◽  
Retrieval Task ◽  
Absolute Size ◽  
The Absolute ◽  
Motor Areas

Neuroimaging studies in stroke survivors have suggested that adaptive plasticity occurs following stroke. However, the complex temporal dynamics of neural reorganization after injury make the interpretation of functional imaging studies equivocal. In the present study in adult squirrel monkeys, intracortical microstimulation (ICMS) techniques were used to monitor changes in representational maps of the distal forelimb in the supplementary motor area (SMA) after a unilateral ischemic infarct of primary motor (M1) and premotor distal forelimb representations (DFLs). In each animal, ICMS maps were derived at early (3 wk) and late (13 wk) postinfarct stages. Lesions resulted in severe deficits in motor abilities on a reach and retrieval task. Limited behavioral recovery occurred and plateaued at 3 wk postinfarct. At both early and late postinfarct stages, distal forelimb movements could still be evoked by ICMS in SMA at low current levels. However, the size of the SMA DFL changed after the infarct. In particular, wrist-forearm representations enlarged significantly between early and late stages, attaining a size substantially larger than the preinfarct area. At the late postinfarct stage, the expansion in the SMA DFL area was directly proportional to the absolute size of the lesion. The motor performance scores were positively correlated to the absolute size of the SMA DFL at the late postinfarct stage. Together, these data suggest that, at least in squirrel monkeys, descending output from M1 and dorsal and ventral premotor cortices is not necessary for SMA representations to be maintained and that SMA motor output maps undergo delayed increases in representational area after damage to other motor areas. Finally, the role of SMA in recovery of function after such lesions remains unclear because behavioral recovery appears to precede neurophysiological map changes.

Trends in the population of the Northern Hairy-nosed Wombat Lasiorhinus krefftii in Epping Forest National Park, Central Queensland

1994 ◽  
Vol 1 (2) ◽  
pp. 141 ◽  
Author(s):  
Doug G. Crossman ◽  
Christopher N. Johnsow ◽  
Alan B. Horsup
Keyword(s):  
National Park ◽  
Absolute Size ◽  
Forest Region ◽  
Prolonged Drought ◽  
Males And Females ◽  
The Absolute ◽  
The Stability ◽  
Almost All

The Northern Hairy-nosed Wombat Lasiorhinus krefftii now survives only in Epping Forest National Park, central Queensland. The species was formerly more widespread in the Epping Forest region than at present. Its decline appears to have occurred in three distinct episodes of contraction, two of which were associated with prolonged drought. Indirect monitoring of abundance suggests that the population was stable from 1974 to 1981, when cattle were excluded from the Park, but has increased since 1983. A trapping programme between 1985 and 1989 suggests that the absolute size of the population may be about 70. The population contains approximately equal numbers of males and females; almost all females breed; and a large and apparently increasing proportion of the population consists of young animals. Further increases in density and range within Epping Forest National Park appear possible. Removal of some animals for translocation should be attempted when it is clear that such removals will not jeopardize the stability and vigour of the Epping Forest population.

XIX.—“ Spheroidal”: A Mutant in Drosophila funebris affecting Egg Size and Shape, and Fecundity

1938 ◽  
Vol 57 ◽  
pp. 255-268 ◽  
Author(s):  
F. A. E. Crew ◽  
Charlotte Auerbach
Keyword(s):  
Egg Size ◽  
Morphological Aspect ◽  
New Mutation ◽  
Size And Shape ◽  
Egg Shape

In the course of a study of fecundity in Drosophila funebris (Donald and Lamy, 1937), it was noted that a particular female was laying very few eggs, and that the shape of these was peculiar. Among her descendants other females of similarly low fecundity and laying eggs of the same abnormal shape were encountered, and it was assumed therefore that a mutation affecting fecundity and egg shape had been recognised. In this paper evidence concerning the type of heredity of these characteristics is presented, and a statistical description of the morphological aspect of the new mutation, the size and shape of the egg, as compared with those of the normal D. funebris egg, is given.

Fiddler Crabs Use the Visual Horizon to Distinguish Predators from Conspecifics: A Review of the Evidence

1997 ◽  
Vol 77 (1) ◽  
pp. 43-54 ◽  
Author(s):  
John Layne ◽  
Michael Land ◽  
Jochen Zeil
Keyword(s):  
Field Experiments ◽  
Angular Size ◽  
White Background ◽  
Fiddler Crabs ◽  
Absolute Size ◽  
Uca Pugilator ◽  
Glass Dish ◽  
Escape Responses ◽  
The Absolute

Male fiddler crabs, Uca pugilator (Crustacea: Decapoda), respond to conspecifics by claw waving, and to predators by freezing or escape. In field experiments it was found that this distinction was not made on the basis of angular size and speed, nor was shape important. The remaining possibilities were either the absolute size of the stimulus, determined from angular size and distance, or the position of the stimulus relative to the horizon. To distinguish between these, a crab was placed in a glass dish, and moved black stimuli on a white background, at a distance of 22 cm. Stimuli below the crab's horizon hardly ever evoked escape. However, identical stimuli partially or wholly above the crab's horizon produced escape responses whose frequency varied with the angular size of the stimulus. Halving the distance of the stimulus showed that it was angular and not absolute size that determines escape frequency; and experiments with a tilted horizon showed that it is the position of the stimulus relative to the eye equator that is important, rather than the geographical horizon itself. It has been concluded that crabs categorize stimuli as dangerous or otherwise by their position relative to the crabs’ visual horizon.

Comments on the concentration-dependence of the viscosity of solutions of discrete particles in a homogeneous continuum

1979 ◽  
Vol 44 (7) ◽  
pp. 2086-2091
Author(s):  
Josef Kovář ◽  
Miloslav Bohdanecký
Keyword(s):  
Concentration Dependence ◽  
Volume Fraction ◽  
Individual Particle ◽  
Absolute Size ◽  
Mathematical Relation ◽  
The Absolute ◽  
Size Of Particles

It has been demonstrated that, for systems containing discrete particles dispersed in a continuum, the mathematical relation between viscosity and concentration is the same over the whole concentration range, provided that certain conditions are fulfilled; those conditions are: a) concentration is expressed as the volume fraction of the particles in the solution; b) the particles interact only hydrodynamically. This statement is true both for monodisperse solutions, in which the absolute size of particles may vary from one solution to another and for heterodisperse solutions but in the latter case it must be stipulated that all the solutions must contain the same qualitative distribution of shapes and sizes, so that they differ from one another only in the sense that each individual particle is scaled (up or down) relatively to the corresponding particle in another solution by a factor which is constant for all the particles.

Granivore seed-size preferences

2011 ◽  
Vol 21 (2) ◽  
pp. 81-83 ◽  
Author(s):  
Troy M. Radtke
Keyword(s):  
Seed Size ◽  
Optimal Foraging ◽  
Optimal Foraging Theory ◽  
Foraging Theory ◽  
Absolute Size ◽  
Herbaceous Communities ◽  
The Absolute ◽  
Size Preference ◽  
As If

AbstractAlthough seed-size preference by granivores is relative to the sizes of seeds offered by researchers, preferences are often inappropriately discussed and interpreted as if they are for absolute seed sizes. Granivores often prefer relatively small seeds in forests and relatively large seeds in herbaceous communities, although the absolute size of preferred seeds in each is often similar. These results are consistent with predictions of optimal foraging theory. Researchers are encouraged to take heed of optimal foraging theory and both relative and absolute seed size when interpreting seed-size preferences.

Prospects and Strategies for Housing in the Private Rented Sector

1985 ◽  
Vol 14 (2) ◽  
pp. 151-174 ◽  
Author(s):  
C.M.E. Whitehead ◽  
M. Harloe ◽  
A. Bovaird
Keyword(s):  
Free Market ◽  
Market System ◽  
Absolute Size ◽  
Demand And Supply ◽  
The Future ◽  
The Absolute ◽  
Free Market System ◽  
Rented Sector

AbstractThis second article examines the future of the private rented sector in terms of the types of household that will continue to demand accommodation, the types of landlord that will be prepared to continue to let and the match between the requirements of the two groups. It is predicted that, under present policies, the sector will continue to decline but that the problems that will arise will come more from the mismatch between demand and supply than from the absolute size of the sector. The article then examines possible policies that might help to alleviate these problems. It argues that neither a completely free market system nor strengthening existing controls is likely to prove acceptable. Finally, it suggests a number of possible ways forward within a system of partial controls.

scholarly journals Archer Fish Learn to Compensate for Complex Optical Distortions to Determine the Absolute Size of Their Aerial Prey

2004 ◽  
Vol 14 (17) ◽  
pp. 1565-1568 ◽  
Author(s):  
Stefan Schuster ◽  
Samuel Rossel ◽  
Annette Schmidtmann ◽  
Ilonka Jäger ◽  
Julia Poralla
Keyword(s):  
Absolute Size ◽  
The Absolute

Perceived corruption frequency and size of corruption in economies

2014 ◽  
Vol 7 (1) ◽  
pp. 42-60
Author(s):  
Vivekananda Mukherjee ◽  
Aparajita Roy
Keyword(s):  
Scale Effect ◽  
Absolute Level ◽  
Absolute Size ◽  
Content Type ◽  
Low Level ◽  
Hard Data ◽  
Stable Coalition ◽  
Corruption Perception ◽  
The Absolute ◽  
High Level

Purpose – The paper aims to develop a theoretical model to explain the exact process through which the scale effect works to create a possible wedge between a perception-based ranking like the “Corruption Perception Index (CPI) ” and the axiomatic “absolute costs of corruption”-based ranking of economies with low enforcement against corruption. Design/methodology/approach – The paper takes into account corruption both at the “high” and “low” levels of bureaucracies, where the bribes are paid sequentially at the two levels. The bribes are endogenously determined at the equilibrium using a sequential game approach. Findings – The paper finds that in the absence of coalition between the two levels of bureaucrats, both the absolute level of corruption and the welfare level of the economies are expected to vary inversely with the perceived corruption frequency. The paper also explores the possibility of a stable coalition between the “high” and “low” level bureaucrats and shows that with the perception of a stable coalition being formed, the negative monotonic relation between the corruption frequency and the absolute size of corruption breaks down. Originality/value – First, the paper argues that the ranking of the economies with low enforcement against corruption on the basis of perceived corruption frequency may not reflect the ranking of the economies according to their absolute size of corruption; it points out that the perceived higher corruption frequency in an economy as reflected in CPI can be an indicator of both the lower size of “high” level corruption and absolute size of corruption in the economy. Particularly, this happens in economies where coalition between the “high” and “low” level officials does not form. Second, it identifies the exact way in which the scale effect works to create a difference in the CPI ranking and the axiomatic “absolute costs of corruption”-based ranking and explains why similar difference would exist if “absolute costs of corruption”-based ranking is derived from all the sources of hard data on corruption. Third, it explains why a stable coalition between the “high” and “low” level bureaucrats in economies with low enforcement does not usually form.

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