bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of spermiogenesis in the gastropod Calliotropis glyptus Watson (Prosobranchia: Trochidae)with special reference to the embedded acrosome
Authors: Healy John M. 
Published: February 2005

AbstractTesticular spermatozoa and sperm development in the archaeogastropod Calliotropis glyptus Watson (Trochoidae: Trochidae) are examined using transmission electron microscopy and formalin‐fixed tissues. During spermiogenesis, the acrosome, formed evidently through fusion of Golgi‐derived proacrosomal vesicles, becomes deeply embedded in the condensing spermatid nucleus. Two centrioles (proximal and distal), both showing triplet microtubular substructure, are present in spermatids—the distal centriole giving rise to the sperm tail and its associated rootlet. During formation of the basal invagination in the spermatid nucleus, centrioles, and rootlet move towards the nucleus and come to lie totally within the basal invagination. Mitochondria are initially positioned near the base of the nucleus but subsequently become laterally displaced. Morphology of the mature spermatozoon is modified from that of the classic primitive or ect‐aquasperm type by having 1) the acrosome embedded in the nucleus (the only known example within the Mollusca), 2) a deep basai invagination in the nucleus containing proximal and distal centrioles and an enveloping matrix (derived from the rootlet), 3) laterally displaced periaxonemal mitochondria, and 4) a tail extending from the basal invagination of the nucleus. Implantation of the acrosomal complex and centrioles within imaginations of the nucleus and lateral displacement of mitochondria effectively minimize the length of the sperm head and midpiece. Such modifications may be associated with motility demands, but this remains to be established. The unusual features of C. glyptus spermatozoa, though easily derivable from ‘typical’ trochoid sperm architecture, may prove useful in delineating the genus Calliotropis or tracing its relationship to other genera within the trochid subfamily Margaritinae.
Trout sertoli cells and germ cells in primary culture: I. Morphological and ultrastructural study
Authors: Loir Maurice 
Published: February 2005

AbstractIn order to characterize trout Sertoli cells and germ cells obtained after testis dissociation and cell separation, we have studied their morphology, ultrastructure, survival, and ability to express differentiated activities in primary cultures. After dissociation, the fine structure of Sertoli cells does not differ from that observed in situ and only minor changes are shown for at least 13 days. Until they are flattened in a monolayer, they keep the ability to retain germ cells on their surface. When flattened, some of them are able to divide. At the opposite of meiotic germ cells, spermatogonia can develop independently of Sertoli cells. They are able to proliferate during at least 10 days. Spermatocytes and spermatids are obtained as single cells and multinucleated giant cells (symplasts). In the absence of somatic cells, their maximal viability is approximately 5 days, whereas spermatocytes adhering to Sertoli cells can survive at least 10–12 days, provided trout lipoproteins are present. Spermatocytes are able to differentiate to spermatids, although this process is impaired for some ceils. The adhesion of spermatogonia and spermatocytes to Sertoli cells is specific, mediated by desmosome‐like junctions and favored by lipoproteins. These data are compared to what is known in mammals and in amphibians.
Adrenergic stimulation of sea urchin sperm cells
Authors: Nelson Leonard , Cariello Lucio 
Published: February 2005

AbstractThe noradrenergic agonists norepinephrine and isoproterenol elicit greater stimulatory swim ming responses in sea urchin spermatozoa than epinephrine. The β‐blocker atenolol induces an even greater motile rate, while the α‐blocker phentolamine has only a moderate effect, it also causes a minimal reduction in the sperm cells' response to atenolpol. Caffeine increases the motility but to a lesser degree than 8‐Br‐cAMP. In drug interaction assays, both caffeine and 8‐Br‐cAMP depress the adrenergic effects. Agents that affect access of calcium to the flagellar apparatus (verapamil and trifluoperazine) depress the motility below the level of the controls when incubated separately with the sperm suspensions and counteract the stimulation due to atenolol. Adrenergic modulation of sperm motility thus appears to be both a calcium‐dependent and a cyclic nucleotide‐dependent process.
Lectin binding characterstics of mouse epididymal fluid and sperm extracts
Authors: Rankin Tracy L. , Holland Michael K. , Orgebin‐Crist Marie‐Claire 
Published: February 2005

AbstractGlycoproteins from luminal fluid of the mouse cauda epiciidymidis have been compared with glycoproteins from Triton X‐100 extracts of mouse spermatozoa from varying regions of the epididymis, using lectins with specific affinity for different sugar residues. Concanavalin A recognizes 11 glycocomponents on Western blots of fractionated caudal fluid; wheat germ agglutinin (WGA) binds 12 proteins; Ulex europaeus agglutinin (UEA) binds seven; and Dolichos biflorus agglutinin (DBA) recognizes nine. Several of these glycoproteins display an affinity for more than one lectin, indicating a diversity in their exposed carbohydrate residues; whereas other proteins bind only one of the four lectins used. The results also show that some glycoproteins exhibit a higher affinity for particular lectins. Eight glycoproteins of similar mobility and lectin‐binding characteristics are detected in Triton X‐100 extracts of spermatozoa from different regions of the epididymis and in caudal fluid. The lectin affinity of some proteins appears or increases in spermatozoa from distal epididymal regions (54 kD, 32 kD), whereas the lectin affinity of others decreases (29 kD, 40 kD). There are differences in lectin affinities between proteins in sperm extracts and in caudal fluid. Some proteins show an affinity for three or four lectins in caudal fluid, but proteins of similar electrophoretic mobility in sperm extracts bind only one or two of the lectins. These data show that glycoproteins of similar mobility are present in caudal fluid and in Triton‐X‐100 sperm extracts, implying a potential interaction between caudal fluid components and epididymal sperm.
In vitro capacitation of boar ejaculated spermatozoa: Effect of conditioned media prepared from preincubated sperm suspension
Authors: Hamano S. , Naito K. , Fukuda Y. , Toyoda Y. 
Published: February 2005

AbstractThe fertilizing ability of boar ejaculated spermatozoa was examined in vitro after prcincubation at a concentration of 2.5 × 108/ml for 4 hr in several conditioned media (CM). For preparation of CM, boar spermatozoa were incubated in a modified Krebs‐Ringer bicarbonate solution (TYH) at concentrations of 20 to 40 × 108/ml for several hours up to 4 hr; then their supernatant fluids were collected by centrifugation. When boar ejaculated spermatozoa were preincubated in TYH alone, 14.1% of oocytes were penetrated by them as we reported previously. On the other hand, preincubating them with CM, their fertilizing ability was elevated according as the incubation time of CM preparation was lengthened. The fertilization rate reached 75.0%, using 4 hr‐incubated CM for the preincubation medium. The effect of CM was not deteriorated by heat treatments (56°C, 30 min, or 100°C, 5 min). The components of CM were separated at a molecular weight of 25,000 by ultrafiltration, and high fertilization rate (69.8%) was obtained when low molecular weight fraction was used for the preincubation medium. Sperm extracts prepared from directly frozen‐thawed sperm suspension and 0.1–10 mM of taurine or hypotaurine had no effect on the fertilizing ability of boar spermatozoa. These results suggest that substances stimulating boar sperm capacitation were accumulated from viable spermatozoa into the medium during incubation and that the effective substances were heat‐stable and of low molecular weight and were not taurine and hypotaurine.
Interval estimation of the difference in proportions under m‐to‐one matching
Authors: Lui Kung‐Jong 
Published: February 2005

AbstractWhen the number of potential controls is large relative to the number of available cases, or when little effort needs to be expended in collecting the relevant information on the controls, we often apply multiple matching to attain the validity or increase the efficiency of our inference in epidemiological studies. In this paper, we focus interval estimation on the difference in proportions for m‐to‐one matching. We consider four asymptotic interval estimators, including the estimator directly using the Mantel–Haenszel (MH) point estimator, the estimator using the tanh−1(x) transformation, the estimator derived from the Cochran–Mantel–Haenszel (CMH) test statistic, and the estimator derived from the quadratic inequality developed in this paper. To evaluate and compare the performance of these estimators, we employ Monte Carlo simulation. We find that the estimator directly using the MH estimator can have the coverage probability less than the desired confidence level when the number of matched sets is small. We note that the estimator derived from the quadratic inequality can perform well when the underlying difference is close to 0 even for a small number of matched sets. However, this estimator tends to have the coverage probability less than the desired confidence level as well when the underlying difference in proportions is large. By contrast, the estimator using the CMH statistic tends to have the coverage probability larger than the desired confidence level when the underlying difference is small. We also find that the estimator using the tanh−1(x) transformation consistently outperforms the interval estimator directly using the MH estimator. We use the data regarding the association between induced abortions and ectopic pregnancy to illustrate the use of these estimators. Copyright © 2005 John Wiley & Sons, Ltd.
Single‐Walled Carbon Nanotubes Under the Influence of Dynamic Coordination and Supramolecular Chemistry
Authors: Chichak Kelly S. , Star Alexander , Altoé M. Virginia P. , Stoddart J. Fraser 
Published: February 2005

AbstractA dynamic coordinative‐directed solubilization of single‐walled carbon nanotubes (SWNTs) in aqueous solutions has been achieved through a combination of a ZnII metalloporphyrin complex and a cis‐protected PdII complex, which are believed to form charged acyclic and/or cyclic adducts on or around the side walls of SWNTs. The solubilization of SWNTs in aqueous solution only occurs when these acyclic and/or cyclic complexes are allowed to enter simultaneously into a self‐assembly process with SWNTs under mild conditions. The aqueous solubility properties that these dynamic complexes confer upon SWNTs are believed to involve noncovalent bonding interactions between the two entities. They have been probed in solution using ultraviolet and visible absorption spectroscopy and in thin films using high‐resolution transmission electron microscopy. The supramolecular electronic effects that the individual components of their acyclic and/or cyclic complexes impart upon a single semiconducting SWNT have been probed within a nanotube field‐effect transistor device.
Noble Metal Nanoparticles Deposited on Self‐Assembled Monolayers by Pulsed Laser Deposition Show Coulomb Blockade at Room Temperature
Authors: Speets Emiel A. , Dordi Barbara , Ravoo Bart Jan , Oncel Nuri , Hallbäck Ann‐Sofie , Zandvliet Harold J. W. , Poelsema Bene , Rijnders Guus , Blank Dave H. A. , Reinhoudt David N. 
Published: February 2005

AbstractNanometer‐sized noble‐metal clusters are fabricated on top of alkylthiolate self‐assembled monolayers (SAMs) on annealed gold by pulsed laser deposition at elevated pressures. The size distribution of the clusters depends on the metal and on the pressure during the deposition. Scanning tunneling microscopy (STM) and conductive probe atomic force microscopy (CP‐AFM) showed that the metal clusters are insulated from the substrate on top of the SAM. Coulomb blockades could be measured at room temperature by STM for palladium clusters on decanethiol SAMs.
Carbon Nanotubes for Microelectronics?
Authors: Graham Andrew P. , Duesberg Georg S. , Seidel Robert V. , Liebau Maik , Unger Eugen , Pamler Werner , Kreupl Franz , Hoenlein Wolfgang 
Published: February 2005

AbstractDespite all prophecies of its end, silicon‐based microelectronics still follows Moore's Law and continues to develop rapidly. However, the inherent physical limits will eventually be reached. Carbon nanotubes offer the potential for further miniaturization as long as it is possible to selectively deposit them with defined properties.
A functional logic for higher level reasoning about computation
Authors: Staples John , Robinson Peter J. , Hazel Daniel 
Published: February 2005

Abstract
In many areas of computation and reasoning, the value of an expression may depend on an implicit parameter, which may for example represent a program state, or time, or a possible world. In this paper we describe a formal first order logic which captures a general notion of expressions which depend on an implicit parameter. Both semantics and syntax are discussed. An important application of the logic, used as a running example, is to provide a basis for unifying the Hoare logic of procedural programs with the mathematically powerful techniques of classical logic and set theory. It is, however, beyond the scope of this paper to develop this application fully.
A predicate transformer for the progress property ‘to-always’
Authors: Dijkstra Rutger M. , Sanders Beverly A. 
Published: February 2005

Abstract

The temporal property ‘to-always’ has been proposed for specifying progress properties of concurrent programs. Although the ‘to-always’ properties are a subset of the ‘leads-to’ properties for a given program, ‘to-always’ has more convenient proof rules and in some cases more accurately describes the desired system behavior. In this paper, we give a predicate transformer
wta
, derive some of its properties, and use it to define ‘to-always’. Proof rules for ‘to-always’ are derived from the properties of
wta
. We conclude by briefly describing two application areas, nondeterministic data flow networks and self-stabilizing systems where ‘to-always’ properties are useful.
Distributed maximum maintenance on hierarchically divided graphs
Authors: Lentfert P. J. A. , Swierstra S. D. 
Published: February 2005

Abstract
The design and verification of distributed and concurrent algorithms is highly complex, and thus error-prone. It is our experience that the intertwined use of an informal description as well as a formal method in designing and studying an algorithm, is a fruitful one. The advantage of the informal description is the ease with which algorithms can be produced, studied and discussed. In contrast with formal methods however, errors are easily made in informal arguments about programs that seem to be correct, but in fact are not.
In this paper we use an informal argument, carefully augmented with the use of the UNITY formalism, in the design of a distributed algorithm for maintaining the maximum value of a bag of frequently changing integers on a hierarchically divided network. The resulting algorithm is obtained by first designing an abstract algorithm on a virtual datastructure. Next, the abstract algorithm is transformed into the distributed algorithm.
Partial logics reconsidered: A conservative approach
Authors: Owe Olaf 
Published: February 2005

Abstract
Partial functions play an important role in computer science. In order to reason about partial functions one may extend classical logic to a logic supporting partial functions, a so-called partial logic. Usually such an extension necessitates side-conditions on classical proof rules in order to ensure consistency, and introduces non-classical proof rules in order to maintain completeness. These complications depend on the choice of consequence relation and non-monotonic operators. In computer science applications such complications are undesirable, because they affect (semi-) mechanical reasoning methods, and make manual reasoning difficult for computer scientists who are not logicians.

By carefully choosing the consequence relation and non-monotonic operators, a simple calculus for partial functions arises. The resulting logic is “healthy” in the sense that “meaningless” formulas (such as top(emptystack) > 1) cannot be concluded, except from contradictory or false assumptions, and a meaningless assumption provides no information. This requires all axioms to be healthy; and as a consequence the “excluded middle” (
a
V ¬a) must be weakened (to meaningful
a's
). All the well-known classical rules preserve healthiness and are therefore sound in the logic, provided substitutions are restricted to meaningful terms. This means that program reasoning methods based on classical logic usually can be adapted to the presented partial logic.
MetateM: An introduction
Authors: Barringer H. , Fisher M. , Gabbay D. , Gough G. , Owens R. 
Published: February 2005

AbstractIn this paper a methodology for the use of temporal logic as an executable imperative language is introduced. The approach, which provides a concrete framework, calledMetateM, for executing temporal formulae, is motivated and illustrated through examples. In addition, this introduction provides references to further, more detailed, work relating to theMetateMapproach to executable logics.
Communicating processes with value-passing and assignments
Authors: Hennessy M. , Ingólfsdóttir A. 
Published: February 2005

Abstract

A semantic theory of an imperative language which allows value-passing and assignments as a simple action prefixing is described. Three different semantic approaches are given: denotational based on the mathematical model Acceptance Trees, axiomatic based on inequations and behavioural in terms of testing. The equivalence of these different approaches is shown. The results are compared with similar results for other languages such as
CSP
and
Occam
.
A CCS-based investigation of deadlock in a multi-process electronic mail system
Authors: Brebner Gordon 
Published: February 2005

Abstract
The networking software for a VAX/VMS computer system had been implemented as a collection of communicating processes. One night, an unusually high load on the electronic mail component of the software caused deadlock to occur between two of the processes. This paper describes how the deadlock was analysed by modelling the software using the Calculus of Communicating Systems (CCS) and then by investigating the behaviour of the model using the Edinburgh Concurrency Workbench (CWB). The analysis suggested how the software should be restructured to prevent the problem recurring; the new set of processes was analysed, and shown to be deadlock-free.
The sliding-window protocol revisited
Authors: van de Snepscheut Jan L. A. 
Published: February 2005

Abstract
We give a correctness proof of the sliding-window protocol. Both safety and liveness properties are addressed. We show how faulty channels can be represented as nondeterministic programs. The correctness proof is given as a sequence of correctness-preserving transformations of a sequential program that satisfies the original specification, with the exception that it does not have any faulty channels. We work as long as possible with a sequential program, although the transformation steps are guided by the aim of going to a distributed program. The final transformation steps consist in distributing the actions of the sequential program over a number of processes.
Termination of rewrite systems by elementary interpretations
Authors: Lescanne Pierre 
Published: February 2005

AbstractWe focus on termination proofs of rewrite systems, especially of rewrite systems containing associative and commutative operators. We prove their termination by elementary interpretations, more specifically, by functions defined by addition, multiplication and exponentiation. We discuss a method based on polynomial interpretations and propose an implementation of a mechanisation of the comparison of expressions built with polynomials and exponentials.
VDM and Z: A comparative case study
Authors: Hayes Ian 
Published: February 2005

Abstract
The specification notations of VDM and Z are closely related. They both use model-based specification techniques and share a large part of their mathematical notation. However, the approaches taken to writing specifications differ in other, more subtle, ways.

We present a comparative case study of VDM and Z for specifying database systems. John Fitzgerald and Cliff Jones in their paper entitled “Modularising the formal description of a database system” in the proceedings of
VDM '90: VDM and Z
(LNCS Vol. 428, Springer-Verlag) provide the basis for the comparison. We present equivalent Z specifications to the VDM specifications contained in their paper.

The approach taken in writing the Z specifications is to reuse as much as possible of the Z mathematical toolkit and to build the system specification from specifications of components of the system.
In their paper, Fitzgerald and Jones emphasise their modularisation facilities. While the facilities for modularisation in Z are not as powerful, they are adequate for the specification of the database systems presented.
Eating attitudes in a diverse sample of Israeli adolescent females: a comparison study
Authors: Latzer Y. , Tzischinsky O. 
Published: February 2005

AbstractObjectivesTo estimate the eating attitudes in Israeli Jewish female adolescents.Methods: A representative sample of 1270 females in grades 7–12 from five different Israeli schools from five different residential areas were assessed by EAT‐26.ResultsOf the total sample, 19.5% were identified as having abnormal eating attitudes. In terms of age, the 16 year olds were found to have the significantly highest rate of total and positive EAT‐26 scores. As for school subgroups, the secular boarding schools had the significantly highest rate and the kibbutz had the lowest rate of positive EAT‐26 scores for the total and for all subscales.DiscussionEAT‐26 was found to be a useful tool for screening and identifying at‐risk groups in a large adolescent Israeli population.
The short time horizon in the Russian mind
Authors: Shlapentokh Vladimir 
Published: February 2005

An individual’s vision of the future is an important factor that shapes his or her quality of life and behavior. The character and intensity of this factor varies from society to society, group to group, and from one moment to the next. Four actors are central to the analysis of the Russians’ perspective of the future: the leadership, political elites, business elites and the masses.The members of each of these groups have their own ‘‘time horizon,’’ that is, the length of time in the future that influences their decisions, moods, and quality of life. The length of this period depends mostly on how they perceive the level of stability in society, now and in the future. As an actor’s pessimism about the future increases, the time horizon decreases. In extreme cases, the person’s time horizon can decline to the point where they disregard what may or may not happen tomorrow.Another important factor is the power and readiness of the particular actor to influence the future of society and its institutions, not to mention their own lives. When people believe that it is impossible to change the future, or the fate of their nation, they become either fatalistic, or tend to violate social norms, resulting in crime, corruption and violence. The leadership and the elites in the country play an important role in influencing whether the masses believe that something can be done to change the nation for the better.