scholarly journals XX.—Notes on an Ancient Boat found at Brigg

Archaeologia ◽  
1887 ◽  
Vol 50 (2) ◽  
pp. 361-370 ◽  
Author(s):  
Alfred Atkinson
Keyword(s):  
Primitive Type ◽  
Fair State

In the month of April, 1886, during the excavation of a pit at the Brigg gas-works, a most interesting boat, of a very primitive type, was found. The upper edges of the sides were first bared; and, as these differed from the “car wood” or buried trees which are so often found in the neighbourhood, the workmen fortunately made a further examination, instead of chopping up the timber to remove it piecemeal. It was then seen to be a boat, in a very fair state of preservation.

The Primitive Type of Arahnid Appendage

1928 ◽  
Vol 62 (681) ◽  
pp. 383-384 ◽  
Author(s):  
H. E. Ewing
Keyword(s):  
Primitive Type

scholarly journals On the adaptation of ticks to the habits of their hosts

Parasitology ◽  
1911 ◽  
Vol 4 (1) ◽  
pp. 46-67 ◽  
Author(s):  
George H. F. Nuttall
Keyword(s):  
Larval Stage ◽  
Feeding Habits ◽  
Small Aperture ◽  
Loss Of Life ◽  
Primitive Type ◽  
Prolonged Starvation

A consideration of the facts presented in the foregoing pages appears to warrant certain conclusions which must, however, be regarded in part as provisional and subject to revision when our knowledge of the various species of ticks has become more extended. The views here expressed may prove of practical use in the study of the Ixodidae.The Argasidae represent the relatively primitive type of ticks because they are less constantly parasitic than are the Ixodidae. Their nymphs and adults are rapid feeders and chiefly infest the habitat of their hosts. In certain Argasidae (O. moubata and O. savignyi) the disadvantage of their possessing an “active” larval stage has resulted in the development of an “inactive” larva, i.e. the young nymph being the first to suck blood. In O. megnini we have a considerable adaptation brought about by the difficulty there must be in the tick entering the small aperture of the ear more than once. Owing to the Argasidae infesting the habitats of their hosts, their resistance to prolonged starvation and their rapid feeding habits, they do not need to bring forth a large progeny, because there is less loss of life in the various stages, as compared to Ixodidae, prior to their attaining maturity.The Ixodidae are more highly specialized parasites than the preceding. The majority are parasitic on hosts having no fixed habitat and consequently all stages, as a rule, occur upon the host. In the genus Ixodes we find an adaptation of certain species according to the habits of the hosts upon which they are parasitic. In the species which usually occur upon wandering hosts both sexes are found upon the host, whereas in other species which occur on hosts possessing more or less fixed habitats the males are rarely or never found upon the host. The males of species of Ixodes, both sexes of which occur upon the host, are characterized, as a rule, by the possession of hypostomes with prominent teeth, the reverse being the case in forms wherein the males do not occur upon the host. Where species occur upon a wandering host it is essential, for their propagation in nature, that both sexes should be carried about upon the host.

scholarly journals Functional and Evolutionary Implications of the Distribution of Phosphagens in Primitive-Type Spermatozoa

1998 ◽  
Vol 195 (3) ◽  
pp. 264-272 ◽  
Author(s):  
W. R. Ellington ◽  
S. T. Kinsey
Keyword(s):  
Primitive Type

scholarly journals From Insect Vision to a Novel Bio-Inspired Algorithm for Image Denoising

2020 ◽  
Author(s):  
Manfred Hartbauer
Keyword(s):  
Image Denoising ◽  
Color Images ◽  
Insect Vision ◽  
Night Vision ◽  
Primitive Type ◽  
Noise Estimate ◽  
Local Means ◽  
Static Images ◽  
Image Details ◽  
Novel Algorithm

Night active insects inspired the development of image enhancement methods that uncover the information contained in dim images or movies. Here, I describe a novel bionic night vision (NV) algorithm that operates in the spatial domain to remove noise from static images. The parameters of this NV algorithm can be automatically derived from global image statistics and a primitive type of noise estimate. In a first step, luminance values were ln-transformed, and then adaptive local means’ calculations were executed to remove the remaining noise without degrading fine image details and object contours. Its performance is comparable with several popular denoising methods and can be applied to grey-scale and color images. This novel algorithm can be executed in parallel at the level of pixels on programmable hardware.

The Independence of the Soul from the Body

2019 ◽  
pp. 106-123
Author(s):  
Satoshi Ogihara
Keyword(s):  
The Body ◽  
Primitive Type

Chapter 7 identifies a principle that governs much of Socrates’ discussion in the Philebus and shows how it is at work in 31b–36c, where he discusses bodily pleasures of restoration and begins discussion of psychic pleasures. That is, he starts with the most primitive type of experience in which the soul just passively receives influence from the body (Philebus’ focus in life), and gradually points out more and more significant ways in which the soul works independently from the body. Such a procedure is meant to familiarize Protarchus with Socrates’ viewpoint from which various workings of the soul are valued independently of their power to promote pleasure. To prepare the discussion, the chapter first argues that the Philebus presents no substantial unitary account of pleasure. In particular, the account in terms of restoration of a harmony and the account in terms of filling do not overlap exactly.

Secretion and ultrastructure of the periostracum of some terebratulide brachiopods

1978 ◽  
Vol 202 (1147) ◽  
pp. 191-209 ◽  
Keyword(s):  
Outer Boundary ◽  
Basal Layer ◽  
Dense Layer ◽  
Simple Type ◽  
Cell Region ◽  
Primitive Type ◽  
Representative Species ◽  
Different Types ◽  
History Of ◽  
Partial Resorption

A survey of the periostracum of representative species of living terebratulide brachiopods reveals that it originates within a slot separating the lobate and vesicular cells of the outer mantle lobe and that three fundamentally different types are synthesized beneath a mucopolysaccharide film exuded by the lobate cells. The simplest type, which is found among the Terebratulacea, consist of a uniformly textured, electron-dense layer, either splaying externally at irregular intervals into acutely disposed subsidiary sheets up to 4 μm long as in Terebratulina , or bearing externally scattered secretion droplets and rare vesicles as in Liothyrella . This simple type of periostracum is a correlative of an undifferentiated basal layer which underlies the periostracal succession of all known terebratellaceans, not only in its structure, but also in its secretion by the vesicular cell region of the outer mantle lobe. The basal layer of terebratellaceans, however, supports a complex superstructure. In Waltonia and other terebratellids as well as dallinids, kraussinids, laqueids and possibly platitiids, the superstructure is an elaborate proteinous succession composed of vesicles and secretion droplets amalgamated by accretionary growth and fashioned by partial resorption into a labyrinthine structure covered by fibrillar proteinous rods arranged in undulating interconnected rows. In the megathyridid Gwynia , the superstructure consists of proteinous sheets secreted as a series of isoclinal folds normal to the basal layer. Both types of superstructure as well as the secretion droplets and vesicles of Liothyrella are exuded mainly by distal lobate cells forming the outer boundary of the periostracal slot. This difference in origin between the basal layer and the superstructure precludes consideration of periostraca as chronologically stratified successions. Concordance of the various types with the phylogenetic history of the Order based mainly on the evolution of the lophophore supports, suggests that the simplest periostracum is the most primitive type and that it may have been widespread among Palaeozoic brachiopods.

Ultrastructural study of spermatozoa of the paddlefish, Polyodon spathula

Zygote ◽  
2005 ◽  
Vol 13 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Otilia Zarnescu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Primitive Type ◽  
Polyodon Spathula ◽  
Transmission Electron ◽  
Architectural Features

Paddlefish, Polyodon spathula, spermatozoa were examined by transmission electron microscopy. Their structure has the same characteristic architectural features as sturgeon spermatozoa. Paddlefish spermatozoa are of the primitive type and consist of a rod-shaped head, a midpiece and a long flagellum. The head is about 5.15 mm in length and contains the nucleus and an apical acrosomal complex. Inside the nucleus there are three nuclear channels that begin in the subacrosomal area and have a triple helical arrangement. An nuclear fossa is present centrally, at the posterior end of the nucleus. The midpiece contains a pair of centrioles in a perpendicular arrangement, mitochondria and a narrow cytoplasmic sleeve. The flagellum has a central axoneme with a 9+2 pattern and two lateral projections or fins.

Fertilization and embryonic developmental capacity of epididymal and testicular sperm and immature spermatids and spermatocytes

1997 ◽  
Vol 6 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Orly Lacham-Kaplan ◽  
Alan Trounson
Keyword(s):  
Close Contact ◽  
Mammalian Species ◽  
Type B ◽  
Final Phase ◽  
Testicular Sperm ◽  
Primitive Type ◽  
Developmental Capacity ◽  
Form Type ◽  
Mitotic Proliferation ◽  
Type A Spermatogonia

Spermatogenesis in mammalian species begins after birth. The gonocytes, arrested at G2 of the cell cycle in the foetus, resume mitotic proliferation after birth. As identified in the mouse, the gonocytes migrate towards the periphery of the seminiferous cords at day 4 to day 6 after birth and are located in close contact with the basal lamina. From this stage the gonocytes are referred to as primitive type A spermatogonia. These cells continue mitotic proliferation and differentiate to form type B spermatogonia. By day 10 after birth, many of the type B spermatogonia have formed preleptotene primary spermatocytes which undergo a final phase of DNA synthesis (leptotene) prior to entering meiotic prophase (zygotene).

The Development of the Civilized Mind in the Ancient Civilizations

Philosophy ◽  
1942 ◽  
Vol 17 (67) ◽  
pp. 250-256
Author(s):  
John Murphy
Keyword(s):  
Fourth Century ◽  
Primitive Type ◽  
Modern Mind ◽  
The World ◽  
Science Philosophy ◽  
Natural Variations ◽  
Ancient Civilizations ◽  
The Buddha ◽  
Definite Period ◽  
Hebrew Prophets

The positions which are offered for consideration in this paper may be summarized in the following four points:First, there is a civilized type of mind which may be clearly distinguished from a primitive type.Second, the civilized mind developed from the primitive under certain economic and ethnological conditions which are to be described.Third, this emergence of the civilized mind from the primitive took place at a fairly definite period and reached its height in the remarkable efflorescence of genius between the ninth and fourth century b.c., over an area from Egypt to China. This was the appearance in that period of a mind essentially one in character, with natural variations, in the Greek thinkers, the Hebrew prophets, the early Hindu mystical philosophers and the Buddha in India, and the ethical teachers of China of the Confucian school.Fourth, this type of mind with its characteristic powers was achieved once for all and was never lost. In spite of the decay of most of the ancient civilizations, the civilized mind has been transmitted, chiefly through the survival of Greek and Graeco-Hebraic thought, into science, philosophy, and theology to become the modern mind for the world of culture of to-day.

scholarly journals Non-random distribution of spermatogonia in rats: evidence of niches in the seminiferous tubules

Reproduction ◽  
2003 ◽  
pp. 669-680 ◽  
Author(s):  
H Chiarini-Garcia ◽  
AM Raymer ◽  
LD Russell
Keyword(s):  
Basal Lamina ◽  
Random Distribution ◽  
Type A ◽  
Seminiferous Epithelium ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Primitive Type ◽  
Linear Index ◽  
Type A Spermatogonia

The relationships and distribution of spermatogonia were studied as a function of the stage of the seminiferous epithelium cycle in rats. Primitive spermatogonia in the mouse are located along regions of the basal lamina that face the interstitium. Before studying the distribution of spermatogonia in rats, it was necessary to characterize the various types of spermatogonia, as recently performed for mice. The Strauss' linear index (Li) selectivity method was then used and spermatogonia of the A(single) (A(s)) to A(aligned) (A(al)) lineage were preferentially found to be located in regions opposing the interstitium at stages V, VII and IX of the spermatogenic cycle. Because relatively little tubule-to-tubule contact occurs in rats, the aim of this study was to determine whether tubule-to-tubule contact or tubule proximity (or alternatively, the amount of interstitium) was an important factor in spermatogonial position. In this regard, another method (tubule proximity) was devised to determine spermatogonial position that accounted for the presence of adjacent tubules. This method showed that the position of tubules, rather than tubule contact, was more accurate than the Li method in determining the location of spermatogonia in the rat. The results also showed a non-random distribution of spermatogonia resembling that of the mouse, and that tubule-to-tubule contact is not essential for the positioning of spermatogonia. In conclusion, the results of this study strongly indicate that the most primitive type A spermatogonia (A(s), A(paired) and A(al)) in rats are present in niches located in those areas of the seminiferous tubules that border the interstitial tissue.

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