Reproductive characteristics of the african pygmy hedgehog, atelerix albiventris

Reproduction ◽  
2000 ◽  
pp. 143-150 ◽  
Author(s):  
JM Bedford ◽  
OB Mock ◽  
SK Nagdas ◽  
VP Winfrey ◽  
GE Olson

To obtain further perspective on reproduction and particularly gamete function among so-called primitive mammals presently grouped in the Order Insectivora, we have examined the African hedgehog, Atelerix albiventris, in light of unusual features reported in shrews and moles. Atelerix proves to share many but not all of the characteristics seen in these other insectivores. The penis of Atelerix has a 'snail-like' form, but lacks the surface spines common in insectivores and a number of other mammals. Hedgehog spermatozoa display an eccentric insertion of the tail on the sperm head, and they manifest the barbs on the perforatorium that, in shrews, probably effect the initial binding of the sperm head to the zona pellucida. As a possible correlate, the structural matrix of the hedgehog acrosome comprises only two main components, as judged by immunoblotting, rather than the complex of peptides seen in the matrix of some higher mammals. The Fallopian tube of Atelerix is relatively simple; it displays only minor differences in width and in the arborized epithelium between the isthmus and ampulla, and shows no evidence of the unusual sperm crypts that characterize the isthmus or ampulla, depending on the species, in shrews and moles. In common with other insectivores, Atelerix appears to be an induced ovulator, as judged by the ovulation of some 6-8 eggs by about 23 h after injection of hCG. The dense cumulus oophorus appeared to have little matrix, in keeping with the modest dimensions of the tubal ampulla and, while it was not quite as discrete as that of soricids, it did show the same insensitivity to 0.5% (w/v) ovine or bovine hyaluronidase.

1952 ◽  
Vol 5 (4) ◽  
pp. 460 ◽  
Author(s):  
AWH Braden

The properties of the membranes of rat and rabbit eggs-the zona pellucida, cumulus oophorus, and in the rabbit, the so-called "albumen" layerhave been studied. By histochemical techniques, it has been shown that all the membranes contain a large proportion of polysaccharide. The zonas are shown to be neutral or weakly acidic mucoproteins, being less acidic than the matrix of the cumulus oophorus, which is composed of hyaluronic acid and protein. Protein is demonstrable histochemically only in the zonas, but ready dissolution of the "albumen" layer and the matrix of the cumulus by pure proteinases indicates that protein forms an integral part of the structure of these layers. The term "albumen" is inappropriate, as the layer so designated has the properties of a strongly acidic mucoprotein.


Author(s):  
S. A. Bortz

Experiments have been performed which indicate the potential of metal-fiber reinforced-ceramic matrix composites for use as a high temperature structural matrix. The results of this work reveal that metal-fiber reinforced ceramics obey compostie theory, and that after cracks occur in the matrix, a pseudo-ductility can be introduced into the composite. This toughness can be predicted from equations of work required to pull the fibers through the matrix. The relationship between strength, toughness, and crack depths, are dependent on the inter-facial bond between the fibers and matrix as well as fiber diameter and length. Based on the results of these experiments, multicomponent materials with superior resistance to failure from oxidation, thermal shock, and high mechanical stresses in air above 2400 F can be postulated. These materials have potential for use as gas turbine engine vanes.


1988 ◽  
Vol 36 (11) ◽  
pp. 1441-1447 ◽  
Author(s):  
F W Kan ◽  
S St-Jacques ◽  
G Bleau

The zona pellucida is an extracellular matrix of glycoproteins which surrounds the mammalian oocyte and preimplantation embryo. We have recently developed monoclonal antibodies against oviductal zona pellucida of the golden hamster. We applied the post-embedding immunocytochemical method using a monoclonal antibody (IgGl,k) to determine the precise location of antigenic sites in the cumulus oophorus complex of the superovulated hamster. By applying the high-resolution protein A-gold technique, we demonstrated that the sites of immunoreactivity were exclusively in the zona pellucida encompassing the oocyte. Other structures within the oocyte and neighboring cumulus cells were not labeled by gold particles. Moreover, gold particles were evenly distributed throughout the entire thickness of the zona pellucida, indicating that this extracellular layer is at least in part made up of an antigen recognized by the monoclonal antibody that is uniformly distributed in the zona matrix.


1963 ◽  
Vol 26 (3) ◽  
pp. 307-NP ◽  
Author(s):  
M. J. K. HARPER

SUMMARY Fifty-five mature oestrous does were injected intravenously with luteinizing hormone (LH) and subsequently killed between 9 hr. 52 min. and 14 hr. 30 min. after injection. At autopsy the number of freshly ruptured follicles was counted and was expressed as a percentage of the total number of follicles (ruptured and unruptured) counted, that had undergone pre-ovulatory swelling. This method of calculating 'percentage ovulation' gave results which agreed very closely with previously reported data. The calculation showed no ovulation by 10 hr., 50% ovulation between 10½ and 10¾ hr., and 100% ovulation by 14 hr. after the injection of LH. In thirty-nine out of these fifty-five does a special study was carried out to determine in what position (in the ruptured follicle, on the surface of the ovary or in the Fallopian tube) the eggs from the ruptured follicles were recovered in relation to the time elapsing after LH injection. Between 10½ and 11½ hr. after injection about 17% of the eggs were found either still inside the ruptured follicle, or within the cumulus oophorus protruding from the follicle or adhering to the ovarian surface. However, at 11½–13 hr. after injection only 3·6–5·9% were still in the follicle or on the ovarian surface. From 13 hr. after LH injection all the eggs recovered were found in the Fallopian tube. These results suggest that not all the eggs are ejected from the follicle at the time of rupture, and that some appreciable time may elapse between follicular rupture and entry of eggs into the tube.


1967 ◽  
Vol 18 (5) ◽  
pp. 755 ◽  
Author(s):  
RJ Lightfoot ◽  
KP Croker ◽  
HG Neil

Sixteen ewes were drawn from each of two ewe flocks, one of which had grazed on oestrogenic pastures for annual periods over the previous 5 years ("clover" treatment) while the other grazed on green oats ("oats" treatment). Fertility of ewes on the clover treatment had decreased progressively, whereas in those on the oats treatment it had remained high. Oestrous ewes were allocated alternately to receive either two or eight services then killed 24 hr post coitus and the numbers of sperm in the cervix, uterus, and fallopian tubes determined. There was no difference in ovarian activity between the two groups; however, highly significant differences were found in the numbers of sperm recovered from the cervix, uterus, and fallopian tubes. Average sperm numbers per fallopian tube were 17,160 and 350 for ewes on the oats and clover treatments respectively. In addition to the reduction in sperm numbers, both the percentage of motile sperm flushed from the cervix and the proportion of recovered ova with sperm attached to the zona pellucida were lower in ewes on the clover treatment. The results suggest that primary failure of sperm transport in ewes on the clover treatment occurred when sperm did not enter the cervix in adequate numbers following service. The significance of these observations in relation to possible causal mechanisms is discussed.


Reproduction ◽  
2011 ◽  
Vol 142 (3) ◽  
pp. 409-415 ◽  
Author(s):  
Sumio Ishijima

The flagellar force generated by a hyperactivated monkey spermatozoon was evaluated using the resistive force theory applied to the activated (nonhyperactivated) and hyperactivated flagellar waves that were obtained using high-speed video microscopy and digital image processing in order to clarify the mechanism of sperm penetration through the zona pellucida. No difference in the maximum propulsive force, which was parallel to the longitudinal sperm head axis, was found between the activated and hyperactivated spermatozoa. The maximum transverse force (45 pN), which was perpendicular to the longitudinal sperm head axis, of the hyperactivated spermatozoon was ∼2.5 times its propulsive force. As the beat frequency of the flagellar beating remarkably decreased during the hyperactivation, the slowly oscillating transverse force (5 Hz) by the hyperactivated spermatozoon seems to be most effective for sperm penetration through the zona pellucida.


Author(s):  
Nathan Salowitz ◽  
Ameralys Correa ◽  
Afsaneh Moghadam

Self-healing material structures with the inherent capability to mend damage will lead to a paradigm shift in design as fracture may no longer constitute a failure. Generally, there are two techniques of self-healing that operate at different scales, require different approaches and often are dealt with separately; geometric restoration and crack filling/bonding. Geometric restoration uses shape memory materials that can mechanically close fractures after they occur. Crack filling and bonding fills and chemically bonds fractured parts in place. Materials capable of recovering from complete fractures, that have propagated across the entire component, have typically taken a sparse fiber composite form with a structural matrix encapsulating shape memory fibers. This form of self-healing material has demonstrated the ability recover original bulk geometry. However, lacking bonding, the healed structures have not had the ability to resist subsequent externally applied loads without re-opening the crack. A new approach of pre-straining the shape memory fibers before curing them in a matrix in the pre-strained state is presented in this paper with basic theory and experimental results. Pre-straining the shape memory fibers before casting them in the matrix causes them to undergo constrained recovery upon activation. Thus, the samples create closing loads across the crack which are capable of withstanding external loads without re-opening.


1989 ◽  
Vol 23 (3) ◽  
pp. 279-287 ◽  
Author(s):  
Lesley McGregor ◽  
Sean P. Flaherty ◽  
William G. Breed

Author(s):  
Елена Васильевна Бутенко

Введение. Проведено лингвостилистическое исследование паремиологических трансформаций в кинотексте и рассмотрены возможности эквивалентной передачи трансформа в языке перевода. Актуальность исследования обусловлена широкой употребительностью пословичных единиц в художественном языке, в частности в кинодискурсе. Встраиваясь в матрицу кинодиалога, они становятся основой для последующих преобразований в высказываниях персонажей, создавая своей окказиональностью значительный экспрессивный потенциал. Цель. Поскольку свидетельством эффективной трансформации является узнаваемость исходной пословицы в трансформе, целью исследования стало выявление лингвостилистических средств, способствующих узнаванию, декодированию и адекватному зрительскому восприятию трансформа в языке принимающей культуры. Материал и методы. Материалом исследования послужили пословичные трансформы в высказываниях персонажей анимационного фильма “The Lion King. Hakuna Matata” («Король Лев. Акуна Матата»). Проводимое исследование имело теоретико-эмпирический характер, при котором анализ материала осуществлялся посредством структурного и описательного методов, позволяющих установить определенные лингвистические закономерности паремиологических трансформаций. Результаты и обсуждение. Анализируемый авторский трансформ является по сути сентенцией, афористическим, то есть лаконичным и поучительным, изречением. Сентенция воспроизводит типические черты народной пословицы: дидактичность, переосмысленность, имплицитность. Оживляя традиционную форму паремиологической единицы, она сохраняет семантико-стилистическое тождество с прецедентным текстом. Наряду со смысловой тождественностью с исходной пословицей, трансформ-сентенция демонстрирует и синтаксическую схожесть, при этом бесшовно включаясь в контекст диалога. Констатируемые проявления трансформационного процесса закономерны, так как трансформ создается по пословичным алгоритмам, что обеспечивает его соотносимость с исходной пословицей. Их имплицитная общность предопределяет и в некоторой степени ограничивает вариативность лексического содержания, а также синтаксической структуры трансформа. Это дедуктивное положение может стать небольшим научным вкладом в лингвостилистические исследования в области паремиологической трансформации. Оно эффективно работает в художественном языке, где обеспечивающая адекватное восприятие логическая структура традиционной пословицы способна производить дериваты, выделяющиеся своеобразием формы. Проводимым лингвостилистическим исследованием изучаются людические (игровые) ресурсы полисемии, применяемые в трансформе, и анализируются изыскиваемые возможности перевода каламбурных речений. Внесение модифицированной пословичной единицы – сентенции – в структуру кинодиалога рассматривается как прием стилистической цитации, функциональная ценность которой подтверждается уместностью употребления в определенной ситуации общения. Статус интертекстуального знака, приобретаемый сентенцией в высказывании персонажа, наделяет ее особой значимостью и способствует возникновению направленных ассоциаций, служит средством усиления аргументации и выражения оценки. Заключение. Трансформация паремиологических единиц – это результат художественно-обработанного прецедентного текста, где структурно-семантическая устойчивость обновляется окказиональным, но идентичным по содержанию выражением. Таким образом, модифицированные паремии не воспринимаются как безжизненные фольклорные штампы, они являются актуальными составляющими речевого узуса. Поскольку краткость входит одним из основных компонентов в понятие «пословица», ее семантико-стилистическому деривату также свойственны смысловая емкость и синтаксическая сжатость. Подобные формы способствуют созданию языковой компрессии, необходимой в субтитровании, наиболее востребованном виде киноперевода. Этот фактор подтверждает как практическую значимость исследования, так и его актуальность для киноиндустрии. Introduction. The linguistic research analyzes paremiological transformations in the film text and stud-ies the possibilities of their equivalent translation in the host culture. The relevance of the study is due to the wide use of proverbial units in the artistic language and namely in film discourse. Embedded in the matrix of the film dialogue, they become a basis for subsequent transformations in characters’ speech, creating a significant expressive potential because of their occasional character. Aim and objectives. Since the recognition of the original proverb in the modified version is the proof of an effective transformation, the aim of the study is to identify the linguistic means that contribute to recognition, decoding and adequate perception of the transform in the language of the host culture. Material and methods. The research is based on the proverbial transforms in the characters’ utterances of the animated film “The Lion King. Hakuna Matata”. Being of a theoretical-empirical nature, the lingua-stylistic study required the use of the structural and descriptive methods, which made it possible to pinpoint certain linguistic regularities of paremiological transformations. Results and discussion. The analyzed author’s transform is actually an epigram – an anaphoristic statement, concise and instructive. It reproduces the typical features of a proverb: didacticity, transfig-uration, implication. Renewing the traditional form of the paremiological unit, the epigram retains the semantic-stylistic identity with the precedent text. Alongside the semantic identity with the proverbial prototype, the transform also demonstrates the syntactic similarity, while seamlessly integrating into the context of the dialogue. The stated manifestations of the transformation process are explicable, since the transform is created according to proverbial algorithms, which ensure its correlation with the original proverb. The implicit mutuality predetermines and limits, to a certan extent, the variability of the lexical content and the syn-tactic pattern of a transform. This deductive reasoning can be a scientific contribution to the lingua-stylistic research in the sphere of paremiological transformation. It works efficiently in the artistic lan-guage, where, ensuring an adequate perception, the logical framework of a traditional proverb pro-duces derivatives, various and expressive in form. The lingua-stylistic research explores the game art resources of polysemy used in the transformation unit, and analyzes the exploited possibilities of translating a pun. The introduction of a modified proverbial unit — an epigram, for example – into the structure of a film dialogue is viewed as a stylistic citation technique, the functional value of which is confirmed by the appropriateness of its use in a certain situation of communication. The status of an intertextual unit, acquired by a transform in a character’s utterance, endows it with special significance and promotes the emergence of directed associations, serves as a means of strengthening argumentation and assess-ment. Conclusion. The transformation of paremias is the outcome of an artistically processed precedent text, where the structural and semantic fixity is revived by an expression, identical in content, but peculiar in form. Thus modified paremias are not perceived as lifeless folklore cliches, but real live compo-nents of speech use. Since brevity is one of the main components in the concept of «a proverb», its derivative is also char-acterized by semantic capacity and syntactic conciseness. Such models contribute to the creation of language compression required in subtitling, the most popular kind of film translation. This factor con-firms both the practical significance of the study and its relevance for the film industry.


2018 ◽  
Vol 16 (1) ◽  
pp. 437-444 ◽  
Author(s):  
Elena A. Kandrashina ◽  
Anna S. Zotova

The creation of new management methods that guarantee sustainable economic development in the long-term perspective is impossible without the overall analysis of the existing methods and system elements of enterprise management. Such analysis should take into account the influence of external and internal environment. Most of Russian organizations functioning at the market are characterized by low degree of flexibility and adaptability to the changes at the market and by traditional ways of management which do not correspond to the modern market conditions and it does not allow them to develop perfectly. The article defines the main components of the enterprise sustainable development and offers the matrix model of changes assessment on the basis of sustainable development criterion.Thus, the general aim of the article is to form theoretical and methodical basis for management mechanism aimed at sustainable development of the enterprise, the mechanism that meets the current demands and global trends of economy development. The main methodical instrument used for the enterprise position assessment is the system of matrix coordinates. The choice of the matrix form is due to the fact that matrices are the main tool for strategic positioning of enterprises and the choice of strategic solutions in conditions of multiplicity of parameters through which the expected and actually obtained results are formalized and measured.


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