bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early lexical development: the contribution of parental labelling and infants' categorization abilities
Authors: Poulin-Dubois Diane , Graham Susan , Sippola Lorrie 
Published: September 2008

ABSTRACTIn the present longitudinal study, we examined changes in parental labelling and infants' categorization skills as potential predictors of vocabulary composition, the age of the naming explosion, and the acquisition of subordinate labels. Sixteen French- and English-speaking parent–child dyads were videotaped during a 2O-minute free-play session every month beginning when the child was 1;0 and ending at 2;0. The children received object-manipulation tasks every three months and their vocabulary growth was recorded. Parental labelling practices were assessed monthly using a picture-book reading task. Both parental labelling and children's categorization skills predicted the content of children's lexicon, with children with more names in their vocabulary having better categorization skills. Furthermore, the naming explosion was found to coincide with improvement of categorization skills. These findings suggest that the influence of each factor varies as a function of the stage and aspect of lexical development considered.
Rice balls and bear hunts: Japanese and North American family narrative patterns
Authors: Minami Masahiko , McCabe Allyssa 
Published: September 2008

ABSTRACTIn past research, the form of Japanese children's personal narratives was found to be distinctly different from that of English-speaking children. Despite follow-up questions that encouraged them to talk about one personal narrative at length, Japanese children spoke succinctly about collections of experiences rather than elaborating on any one experience in particular (Minami & McCabe, 1991). Conversations between mothers and children in the two cultures were examined in order partly to account for the way in which cultural narrative style is transmitted to children. Comparison of mothers from the two cultures yielded the following salient contrasts: (1) In comparison to the North American mothers, the Japanese mothers requested proportionately less description from their children. (2) Both in terms of frequency and proportion, the Japanese mothers gave less evaluation and showed more verbal attention to children than did North American mothers. (3) Japanese mothers pay verbal attention more frequently to boys than to girls. In addition, at five years, Japanese children produce 1·22 utterances per turn on average, while North American children produce 2·00 utterances per turn, a significant difference. Thus, by frequently showing verbal attention to their children's narrative contributions, Japanese mothers not only support their children's talk about the past but also make sure that it begins to take the shape of narration valued in their culture. The production of short narratives in Japan is understood and valued differently from such production in North America.
Children's comprehension of the distinction betweenwantandneed
Authors: Moore Chris , Gilbert Cheryl , Sapp Felicity 
Published: September 2008

ABSTRACTTwo experiments examined the development of children's understanding of the difference betweenwantandneed. In experiment 1, children were tested on their knowledge thatwantrepresents an intrinsic desire whereasneedrepresents an instrumental desire. Forty-five children between three and five years of age heard four stories in which one character encountered a problem, while another did not. A desirable object which could alleviate the problem was then introduced, and after both characters requested the object, the children were asked whether each characterwantsthe object orneedsit. Three-year-olds were unable to differentiate the two terms in such contexts, whereas four- and five-year-olds were significantly more likely to say that the character experiencing the problem needed the object, while the other wanted it. In experiment 2, 45 subjects between three and five years of age were tested on their understanding that a request employingneedexpresses a stronger desire than one employingwant. Subjects were required to give an object to one of two characters, one of whom asked for it usingneedand the other usingwant. In this experiment, three-year-olds were equally likely to give the object to the character usingwantas to the one usingneed. Both four- and five–year–olds were significantly more likely to give the object to the character who usedneed. The results from these two experiments show that the understanding of the semantic and pragmatic difference betweenwantandneeddevelops at about four years of age.
An experimental test of phonemic cyclicity
Authors: Gierut Judith A. 
Published: September 2008

ABSTRACTLaryngeal-supralaryngeal cyclicity has been put forth as an acquisition principle that describes expansion of the phonemic inventory as a bivalent cycle with alternations between the elaboration of laryngeal and supralaryngeal properties of the system (Gierut, 1994). This study evaluated experimentally the claims of the principle by manipulating the domain of the cycle and the phase relationship of the cycle as independent variables, and by monitoring longitudinally the order of emergent phonemic distinctions in the sound systems of seven children with phonological delays (aged 3;4 to 5;8) as the dependent variable. Three general findings emerged: (1) the course of acquisition for all children was consistent with cyclicity; (2) there were no differences in phonemic acquisition between children taught a laryngeal as opposed to a supralaryngeal distinction; and (3) children taught out-of-phase with the cycle evidenced greater phonemic expansion than those taught inphase with the cycle.
Measuring the vocabulary spurt: a reply to Mervis & Bertrand
Authors: Goldfield Beverly A. , Reznick J. Steven 
Published: September 2008

ABSTRACTWe reply to Mervis & Bertrand's report of three children (aged 1; 6–1; 8 at the start of the study) who evidenced a ‘late’ vocabulary spurt. Differences in assessing productive vocabulary, and the questionable inference that size of the lexicon is a reliable indicator of the vocabulary spurt, make it inappropriate to compare these children to previous studies that directly measure change in rate of word learning. Further work using continuous records of lexical development and controls for repeated cognitive assessments is needed to test hypotheses about the spurt and related cognitive and linguistic achievements.
A mathematical model for washing a tow of fibres: Part 2
Authors: Byatt-Smith J. G. , Terrill E. L. 
Published: September 2008

In Part I of this paper (Terrill & Byatt-Smith, 1993) the problem of the flow between an obstacle in the form of a wedge and a porous flexible tow was modelled using lubrication theory. In the region close to the wedge where bending is important the following equationwas derived for the non-dimensional gap width,H(X), between the tow and the wedge.
On the asymptotics of solutions of a class of linear functional-differential equations
Authors: Derfel G. , Vogl F. 
Published: September 2008

A sharp estimate of the growth of solutions of the initial value problem for systems of the formwhere Cj(t) are matrices with elements of power growth, is found. As a corollary of this result, it follows, for instance, that each solution of the initial value problem satisfies the estimate ‖u(t)‖ ≤ Cexp{γln2(1+|t|)} for some C > 0 and γ > 0.
Structural and functional differentiation of follicular and oviductal mouse oocytes visualised with FITC-protein conjugates
Authors: Kim Haekwon , Schuetz Allen W. 
Published: September 2008

SummaryThe fluroscence labelling characteristics of mouse oocytes were examined at various stages of periovulatory differentiation using FITC-protein conjugates. The zona pellucida perivitelline space and plasma membrane underwent visible changes which were developmentally and environmentally related. Following exposure to fluorescein isothiocyanate (FITC)-casein conjugates, the zona pellucida (ZP) of germinal vesicle stage (GV) ovarian oocytes exhibited a bright, amorphous, mesh-like staining pattern (immature type). In contrast, mature polar body stage (PB) oocytes, either ovarian or oviductal, displayed faint, spotty fluorescence labelling of the ZP (mature type). The perivitelline space (PVS) of mature ovarian oocytes (12 h post-hCG) failed to label, whereas approximately 50% of oviductal oocytes showed PVS labelling. The incidence of PVS staining increased with postovulatory age, possibly as a result of the accumulation of materials secreted by the oviduct. Followingin vivoorin vitrofertilisation of oocytes, a characteristic pattern of plasma membrane (PM) labelling was observed. Similar patterns of PM labelling were seen in oocytes parthenogenetically activated with ethanol or ionophore (A23187) but not in control oocytes. The pattern of PM labelling observed with FITC-protein conjugates was strikingly similar to that observed with FITC-labelled lectins, which are thought to interact with glycoconjugates released from cortical granules. Immature type of ZP staining also occurred when GV oocytes were treated with FITC alone or with a variety of FITC-protein conjugates. Thus, protein may not be required for labelling of the ZP by FITC-protein conjugates as previously thought. FITCconjugated proteins including casein, bovine serum albumin, peroxidase and non-immune immunoglobulin G (IgG), all labelled the PM of activated oocytes; however, FITC-IgG failed to label the PVS. Results demonstrate for the first time that various components of viable mouse oocytes exhibit and undergo characteristic structural and functional changes during periovulatory differentiation as evidenced by their interaction with one or more FITC-protein conjugates and/or FITC. On the basis of these results the intrafollicular and oviductal mechanisms mediating these changes are discussed as is the possibility that the fluorescent molecule attached to conjugates may play a role in oocyte labelling.
The parental origin of the distal pronucleus in dispermic human zygotes
Authors: Tang Ya-xu , Munné Santiago , Reing Adrienne , Schattman Glenn , Grifo Jamie , Cohen Jacques 
Published: September 2008

SummaryThe purpose of this investigation was to determine the parental origin og the pronucleus furthest from the second polar body (the distal pronucleus) in dispermic human zygotes. Infact dispermic embryos (n = 53) and those from which the distal pronucles (n =50) was removed at the zygote stage were biopsied after cleavage. Blastomeres were sexed using either coamplification of X and Y probes using a duplex polymerase chain reaction (PCR), or simultaneous fluorescence in situ hybridisation (FISH) with directly fluorochrome-labelled probes for chromosomes X, Y and 18. The ratio X/Y was determined in both groups of embryos by assessing a minimum of two blastomeres. If the pronuclei in dispermic zygotes are topographcially in a fixed position, the X/Y ratio should change from 1:3 in dispermic embryos to 1:1 in enucleated ones. The ratio of embryos containing only an X chromosome and those with X as well as Y chromosomes in the intact dispermic zygotes was 1.0:2.3 which is similar to the theoretical ratio of 1:3. This ratio was 1.0:1.3 in dispermic zygotes from which the distal pronuclei were removed. This ratio is not significantly different from the 1:1 ratio based on a statistical analysis with a sample size of 50. These sex ratios would have been considered different if more than 200 enucleations had been performed. Although the ratio X/Y was altered following removal of distal pronuclei, suggesting frequent targeting of male pronuclei, accidental removal of the female pronucleus could not be excluded. This indicates that enucleation of dispermic zygotes could produce high yields of gynogenetic and androgenetic embryos for research purposes. Clinical application aimed at producing biparental zygotes may be hazardous, since mosaicism was common among enucleated embryos.
The spindle apparatus in early embryonic divisions ofEphestia Kuehniella Z.(Pyralidae, Lepidoptera) is formed by alignment of minispindles
Authors: Wolf Klaus Werner 
Published: September 2008

SummarySpindles were isolated from deposited eggs of the Mediterranean mealmoth,Ephestia Kuehniella. Their structure and development were studied using anti-tubulin immunofluorescence. The microtubules were labelled with three different monoclonal antibodies. These were directed against β-tubulin, tyrosinated α-tubulin and acetylated α-tubulin. Significant differences in the staining behaviour were not detected with the three antibodies. An unusual mode of spindle formation was observed during the first mitotic division after fusion of the pronuclei. Several of the ensuing embryonic divisions may show the same phenomenon. Prophase of these divisions was characterised by an irregular arrangement of microtubules in the nuclear area. The microtubule mass in the nuclear area increased concomitantly with chromosome condensation. Microtubular foci, comparable to the forming asters of canonical spindles, were not detected. The formation of an orderly pattern in the microtubule mass was signalled by the appearance of minispindles apparently developing around individual chromosomes. Several minispindles subsequently aligned and formed metaphase-like entities within the nuclear area. The metaphase-like entities, in turn, aligned with one another and gave rise to a conventional bipolar metaphase spindle with small asters. The further development of the spindle was conventional. The chromosomes migrated towards the spindle poles and finally daughter nuclei formed. The anaphase and telophase spindles possessed both a prominent array of interzone microtubules and asters. The events in prophase of early embryonic mitosis of E.kuehniellamay represent a rare case of chromosomeinduced spindle formation.
Human cumulus cell complexes studied in vitro by light microscopy and scanning electron microscopy
Authors: Kennedy Sian , England Marjorie A. , Mills Carla 
Published: September 2008

SummaryVarious researchers describe the morphology of cumulus cells (CC) in vitro, but few have investigated their behaviour on plastic. Knowledge concerning the behaviour of human CC could be useful in improving the success of in vitro fertilisation procedures. This study aimed to describe the morphology and behaviour of CC in vitro and to investigate movement on a collagen-coated substrate. Following collection some cumulus were mechanically dissected from those surrounding the oocyte. Cumulus aggregates were cultured over 24 h using Earle's medium supplemented with 8% albumin. Substrata were plastic coverslips coated with collagens I, IV, or mixed collagens. Cumulus cultured over corresponding time periods on uncoated coverslips served as controls. Specimens were fixed and prepared for scanning electron microscopy. Over 24 h the controls began exhibiting the morphological features associated with cell movement: cell surface protrusions changed from blebs to microridges, lamellipodia and leading lamellae; cell shape altered from rounded and upright, to flattened. Extracellularmatrix (ECM) transformed from a thick, sheet-like substance to a thin, fibrous material. By 24 h, cells contacting ECM remained rounded showing few features of movement. Collagens enhanced attachment of CC as a monolayer on the substrate. Cell morphology varied according to the collagen type used. On mixed collagens, cells attached rapidly, appearing to be predominantly non-motile. On collagen type I there was less attachment of cells but increased motility. On collagen type IV there was decreased attachment and the cells remained spherical. In conclusion, collagens enhance the settling of cumulus cells on a plastic substrate and the cells exhibit some specificity in attaching to collagens.
Gap junction communication and cell adhesion in development
Authors: DeHaan Robert L. 
Published: September 2008

AbstractDuring the past decade growing evidence has suggested that cell-cell communication via gap junctions is crucial for early developmental processes (Warneret al., 1984; Guthrie & Gilula, 1989; Serraset al., 1989). It has been shown that embryos of mice (Kalimi & Lo, 1988), teleosts (Kimmelet al., 1984), insects (Warner & Lawrence, 1982; Ruangvoravat & Lo, 1992) and molluscs (Serraset al., 1989) become regionally organized into restricted domains of junctionally connected cells that share developmental potential. In the mouse gastrula, for example, dye-coupling experiments have demonstrated that cells within a developmental compartment have a high degree of coupling whereas cells across compartmental boundaries have reduced coupling (Kalimi & Lo, 1988). Classic experiments (Townes & Holtfretter, 1955; Steinberg, 1963) demonstrated that as cells begin to differentiate along common pathways, they develop selective adhesion properties and the ability to sort themselves from unlike neighbours (for review see Edelman 1988; Edelmanet al., 1990). More recently a multitude of specific cell adhesion molecules (CAMs) have been identified that mediate these processes and trigger the cytoplasmic events that drive further differentiation (Edelmanet al., 1990; Albelda, 1991; Geiger & Ayalon, 1992).
Provisional bilateral symmetry inXenopuseggs is estiblished during maturation
Authors: Brown E.E. , Margelot K.M. , Danilchik M.V. 
Published: September 2008

SummaryDorsal–ventral patterning in theXenopusegg becomes established midway through the first cell cycle during a 30° rotation of the subcortical yolk mass relative to the egg cortex. This rotation of symmetrisation is microtubule dependent, and its direction is thought to be cued by the usually eccentric sperm centrosome. The fact that parthenogenetically activated eggs also undergo a directed rotation, despite the absence of a sperm centrosome, suggests that an endogenous asymmetry in the unfertilised egg supports the directed polymerisation of microtubules in the vegetal cortex, in the way that an eccentric sperm centrosome would in fertilised eggs. Consistent with this idea, we noticed that the maturation spot is usually located an average of more than 15° from the geometric centre of the pigmented animal hemisphere. In parthenogenetically activated eggs, this eccentric maturation spot can be used to predict the direction of rotation. Although in most fertilised eggs the yolk mass rotates toward the sperm entry point (SEP) meridian, occasionally this relationship is perturbed significantly; in such eggs, the maturation spot is never on the same side of the egg as the SEP. In oocytes tilted 90° from upright during maturationin vitro, the maturation spot developed 15° or more from the centre of the pigmented hemisphere, always displaced towards the point on the equator that was up during maturation. This experimentally demonstrated lability is consistent with an off-axis oocyte orientation during oogenesis determining its eccentric maturation spot position, and, in turn, its endogenous rotational bias.
Pronuclear formation and cleavage of mammalian eggs after microsurgical injection of freeze-dried sperm nuclei
Authors: Hoshi Kazuhiko , Yanagida Kaoru , Katayose Haruo , Yazawa Hiroyuki 
Published: September 2008

SummaryA study was conducted to evaluate the ability of mammalian oocytes to develop to the pronuclear stage and beyond if injected with freeze-dried sperm nuclei. The rate of development of hamster eggs to the pronuclear stage after microinjection of freeze-dried hamster sperm nuclei was 90%. The pronuclear formation rate of hamster eggs injected with freeze-dried human sperm nuclei was 85%. On the other hand, the rates for eggs injected with untreated sperm nuclei were 84% and 89% respectively. The survival rate of rabbit eggs microinjected with freeze-dried rabbit sperm nuclei was 64%, the fertilisation rate 56% and the cleavage rate 38%. The survival, fertilisation and cleavage rates of eggs injected with non-freeze-dried sperm nuclei were 78%, 45% and 34%, respectively. There was no difference between eggs injected with freeze-dried sperm nuclei and those injected with sperm nuclei that had not been freeze-dried. Of the viable rabbit eggs injected with freeze-dried rabbit sperm nuclei, 6% developed to the 6- to 8-cell stage 62 h after injection.
Activation of bovine oocytes penetrated after germinal vesicle breakdown
Authors: Abeydeera Lalantha R. , Okuda Kiyoshi , Niwa Koji 
Published: September 2008

SummaryThe present study was designed to examine the ability of bovine oocytes, after germinal vesicle breakdown (GVBD), to be activated by sperm penetration and the sequence of sperm nuclear transformation. Bovine oovytes cultured for 8 h in maturation medium (tissue culture medium TCM-199 containing 10% fetal calf serum) were inseminated in Brackett and Oilphant's medium supplemented with bovine serum albumin (10 mg/ml), caffeine (5mM) and heparin (10 μg/ml). When oocytes were transferrred to the maturation medium 8 h after insemination and additionally cultured for 5−40 h at 39°C in 5% CO2 in air, 71−76% of oocytes were penetrated and polyspermy (67–75%) was common. The proportions of penetrated oocytes that were activated significantly increased with the lapse of the additional culture time, reaching 88% and 87% by 25 and 40 h after additional culture, respectively. When compared with unpenetrated oocytes, signifcantly higher proportions of penetrated oocytes, reached metaphase II or beyond 15 and 25 h after additional culture. After penetration, sperm nuclei were transformed into metaphase chromosomes and then to telophase chromomes before the formation of male pronuclei. These results provide evidence that bovine oocytes acquire the ability to respond to sperm-mediated activation soon after GVBD.
Interactions in glycine and methionine uptake, conversion and incorporation into proteins in the preimplantation mouse embryo
Authors: Khatchadourian Chaqué , Guillaud Josette , Menezo Yves 
Published: September 2008

SummaryGlycine is the most concentrated amino acid in the female genital tract. In this study, we report its conversion and incorporation into proteins in the presence or absence of methionine, in borth 1-cell and blastocyst mouse embryos. The uptake, incorporation and conversion of radiolabelled glycine were studied in the presence or absence of unlabelled methionine. For control purposes, the reciprocal experiment was performed with labelled methionine in the presence or absence of unlabelled glycine. At the 1-cell stage neither glycine uptake nor its incorporation into proteins is inhibited by methionine. Glycine is, however, highly used as an oxidisable energy substrate, via glycolate. At the blastocyst stage, glycine conversion into other amino acids is high and mainly utilised in the formation of glutamic acid. Glycine is highly incorporated into proteins, resulting in a poor exchange of glycine from the preloaded embryos. Methionine competes for glycine uptake and consequently reduces its overall incorporation into proteins. For methionine, neither its uptake nor its incorporation into proteins is reduced in the presence of glycine for the two embryonic stages tested here. The embryo has different mechanisms for incorporation and utilisation of methionine and glycine. Glycine, which has an important function in the embryo, has an inefficient transport system compared with methionine. We were unable to demonstrate the presence of methyiglycine since SAM-glycine-methyltransferase (EC 2.1.1.20) was not detected. The same results were obtained when exogenous methionine was added. We therefore concluded that glycine does not compete in transmethylation within the embryo.