The ability of kittens (45-135 days of age) to segment images based on textural differences was examined using a two-alternative forced-choice procedure on the jumping stand. Tasks based on 3 textural cues--element size, element density and element orientation--were presented concurrently in a within-subject design. Texture segmentation based on element size appeared as early as 47 days of age,...

An intriguing unanswered question about the evolution of bilateral animals with internal skeletons is how an internal skeleton evolved in the first place. Computational modeling of the development of bilateral symmetric organisms suggests an answer to this question. Our hypothesis is that an internal skeleton may have evolved from a bilaterally symmetric ancestor with an external skeleton. By g...

Plants are sessile organisms that are permanently restricted to their site of germination. To compensate for their lack of mobility, plants evolved unique mechanisms enabling them to rapidly react to ever changing environmental conditions and flexibly adapt their postembryonic developmental program. A prominent demonstration of this developmental plasticity is their ability to bend organs in or...

the purpose of performing this research was studying relationship of religious orientation and interpersonal trust with educational progress of students. the research was descriptive correlation one.statistical population included all highschool students of birjand city in educational year 93-94 ,which was based on morgan table and random cluster method ,355 samples was chosen and studied. to g...

Adults exhibit relative behavioral difficulties in processing inanimate, artificial faces compared to real human faces, with implications for using research and designing social agents. However, the developmental trajectory of inanimate face perception is unknown. To address this gap, we used electroencephalography investigate cross-sectional groups 5–10-year-old children adults. A inversion ma...

The functional architecture of mammalian visual cortex has been elucidated in impressive detail by experimental work of the past 20-25 years. The origin of many of the salient features of this architecture, however, has remained unexplained. This paper is the first of three (the others will appear in subsequent issues of these Proceedings) that address the origin and organization of feature-ana...

Cells of the early Caenorhabditis elegans embryo divide in an invariant pattern. Here I show that the division axes of some early cells (EMS and E) are controlled by specific cell-cell contacts (EMS-P2 or E-P3 contact). Altering the orientation of contact between these cells alters the axis along which the mitotic spindle is established, and hence the orientation of cell division. Contact-depen...

For decades, the work of cell and developmental biologists has demonstrated the striking ability of the mesenchyme and the stroma to instruct epithelial form and function in the mammary gland, but the role of extracellular matrix (ECM) molecules in mammary pattern specification has not been elucidated. Here, we show that stromal collagen I (Col-I) fibers in the mammary fat pad are axially orien...

Background: One important reproductive characteristic of Mammals is the production of milk to nurse the neonate. In order to better understand the evolution of milk we have investigated gene expression in milk cells from monotremes which are the most ancient representative of the mammalian lineage. Materials and Methods: Using a milk cell cDNA sequencing approach we characterise milk protein se...