bluuebunny/crossref_metadata_2025_split huggingface dataset:
The cultural basis of prosodic modifications to infants and children: a response to Fernald's universalist theory
Authors: Ingram David 
Published: September 2008

ABSTRACTFernald and her colleagues have argued for the universality of prosodic modifications in speech addressed to infants (e.g. Fernald, 1987; Fernald, Taeschner, Dunn, Papousek, de Boysson-Bardies & Fukui, 1989). An alternative proposal in Bernstein-Ratner & Pye (1984) and Pye (1986) argues that speech modifications to children are the result of a set of conventions that may vary from culture to culture. This note presents arguments against Fernald and in support of the cultural account of prosodic modifications to infants and children. First, in response to criticisms in Fernaldet al., data are presented which defend the conclusion in Bernstein-Ratner & Pye that Quiché mothers show less prosodic modification to children than do mothers in other cultures studied to date. Second, data used to support the universal position in Fernald (1987) on adult identification of infant affective states are reinterpreted and shown to be equally interpretable as the result of a set of culturally transmitted rules.
Phonetic and phonological contrasts in the acquisition of voicing: voice onset time production in Hindi and English
Authors: Davis Katharine 
Published: September 2008

ABSTRACTThe present study examines adult and child word-initial voice onset time productions in English and Hindi (10 adults and 20 children in each language) to determine the age of acquisition of the phonemic voice contrast. Cross-linguistic differences in patterns of acquisition were found, but these need not be traced to the different phonological Systemsper se. An examination of the data indicates that the best predictor of age of voice contrast acquisition across languages is one which rests on the actual acoustic differences between members of phonologically contrastive pairs. In general it was found that the larger the post-release voice onset time differences between pair members in the adult model, the earlier the contrast is reliably produced by child language learners.
Relative clauses are barriers to wh-movement for young children
Authors: Villiers Jill De , Roeper Thomas 
Published: September 2008

ABSTRACTTwo studies are described which investigate preschool children's sensitivity to relative clauses as barriers to the movement of wh-questions. The children were presented with short stories followed by questions in which the wh-word had two possible sites of interpretation, the ungrammatical option being inside a relative clause. A cross-sectional study with 23 children aged 3;1 to 6;1, and a longitudinal study over the course of one year with 12 children aged 3;1 to 4;1 at the start, found young children refused to extract wh-questions from the ungrammatical site inside a relative clause. This confirms other findings that children's early grammars are sensitive to universal constraints on movement. In addition, the children differentiated between wh-complements and relative clauses in their tendency to mistakenly answer the medial wh-complementizer but not the wh-relative pronoun. Explanations for the latter are framed in terms of children's initial assumptions about the attachment of complements.
Functional changes in early child language: the appearance of references to the past and of explanations
Authors: Veneziano Edy , Sinclair Hermina 
Published: September 2008

ABSTRACTSpontaneous speech samples from children during the period of transition from one word to multi-word utterances in interaction with their French-speaking mothers were explored in order to study the appearance and development of functional changes in their use of language. Two types of such change were noted in the longitudinal records of four children when they were still essentially one-word speakers: the beginnings of references to the past, and the appearance of explanations and justifications, especially in communicative situations of request and refusal. The co-appearance of these behaviours is discussed in relation to two more general developmental changes: a detachment from the immediately perceptible situation linked to a further elaboration of the signifier-signified relation, and a socio-cognitive development leading to a view of the interlocutor as an alter ego, as a person whose psychological states may be different from the child's own.
Language differentiation in early bilingual development
Authors: Genesee Fred , Nicoladis Elena , Paradis Johanne 
Published: September 2008

ABSTRACTIt has been claimed that children simultaneously acquiring two languages go through an initial stage when they are unable to differentiate between their two languages. Such claims have been based on the observation that at times virtually all bilingual children mix elements (e.g. lexical, morphological) from their two languages in the same utterance. That most, if not all, children acquiring two languages simultaneously mix linguistic elements in this way is widely documented. Although such code-mixing is not well understood or explained, there are a number of explanations unrelated to lack of language differentiation that may explain it. Moreover, while language differentiation is widely attested among bilingual children once functional categories emerge, usually during the third year, there is still some question as to how early in development differentiation is present. In this study, we examined language differentiation in five bilingual children prior to the emergence of functional categories (they ranged in age from 1;10 to 2;2 and in MLU from 1·23 to 2·08). They were observed with each parent separately and both together, on separate occasions. Our results indicate that while these children did code mix, they were clearly able to differentiate between their two languages. We also examine the possibility that the children's mixing is due to (a) their language dominance, and (b) their parents' rate of mixing. We could find no evidence that their mixing was due to parental input, but there was some evidence that language dominance played a role.
Conserving Mackinder's eagle owls in farmlands of Kenya: assessing the influence of pesticide use, tourism and local knowledge of owl habits in protecting a culturally loathed species
Authors: OGADA DARCY L. , KIBUTHU PAUL MURIITHI 
Published: September 2008

SUMMARYFarmlands can be good habitat for owls and owls can benefit farmers, but pesticide use can negatively affect owls and within many regions of Africa owls are loathed owing to beliefs that they bring misfortune or death. Since 1997, a small-scale owl tourism initiative that educates farmers about owls and benefits them financially has been operating in central Kenya. Pesticide use, farmers' beliefs and knowledge about owls, and the impacts that tourism can have on farmers' attitudes and behaviour towards owls in rural Kenya were surveyed. Agricultural pests were the most serious problem facing farmers, though only 28 % of farmers said they controlled vertebrate pests using pesticides. The insecticide carbofuran was often misused to kill vertebrate pests. Common control measures were either to ‘do nothing’ or to chase pests from farms. Farmers knew of Mackinder's eagle owls living adjacent to their farms, but 68 % said they didn't adhere to the culturally negative beliefs about owls. Knowledge of owl diet amongst farmers was high (75 %). Farmers who benefited from owl tourism were more likely to know more about owl diet and habits. Where farmers gained financial benefits from tourism or knew more about owls, they were more likely to categorize owls as ‘good’, but farmers who knew about owl diet were more likely to use pesticides or kill owl prey on their farms. Though knowledge of owls did not have a positive effect on farmers' behaviour toward owls, this was probably the result of a lack of ecological literacy rather than any deliberate antagonism toward owls. Financial rewards are very important to poor farmers, but may not result in actions that enhance species conservation unless farmers have a basic understanding of ecological processes.
Self-similar solutions of the second kind for the modified porous medium equation
Authors: Hulshof Josephus , Vazquez Juan Luis 
Published: September 2008

We construct compactly supported self-similar solutions of the modified porous medium equation (MPME)They have the formwhere the similarity exponents α and β depend on ε, m and the dimension N. This corresponds to what is known in the literature as anomalous exponents or self-similarity of the second kind, a not completely understood phenomenon. This paper performs a detailed study of the properties of the anomalous exponents of the MPME.
Cloning, sequencing and oocyte-specific expression of the marmoset sperm receptor protein, ZP3
Authors: Thillai-Koothan P , van Duin Marcel , Aitken R. John 
Published: September 2008

SummaryThe zona pellucida surrounding the mammalian oocyte contains a major glycoprotein species, ZP3, that serves as a cell- and species-specific receptor for spermatozoa. In this study we have determined the primary amino acid structure of marmoset ZP3 (marZP3) and examined the expression of marZP3 mRNA within the ovary. The marZP3 gene possesses an open reading frame of 1272 nucleotides which is expressed specifically by the oocyte and encodes a polypeptide chain of 424 amino acids that exhibits 91% homology with the human ZP3 sequence. The disparity between these molecules was confined to a short domain spanning residues 322–352; otherwise the molecules were very similar, showing conservation of many structural features including theN–linked glycosylation sites, location and number of cysteine and proline residues and hydrophobicity profile. The results of this study have important implications for the use of the marmoset monkey as an animal model for the development of contraceptive vaccines targeting ZP3.
Vitrification of rat blastocysts developed in vitro
Authors: Nakamichi R , Ohboshi S , Fujihara N 
Published: September 2008

SummaryApproximately 50% of rat 8-cell embryos obtained from the oviduct on day 4 of pregnancy developed to the balstocyst stage after 18 h of incubation in vitro. The embroys were compared with in vivo blastocysts derived from the uterus on day 5 of pregnancy as regards their response to vitrification treatment. Before vitrification, both types of embryos were exposed to vitrification solution, and subsequent embryonic development was inhibited with increasing time of exposure. A greater suppression of development after exposure was observed in the embryos cultured in vitro compared with in vivo blastocysts. However, development was gradually restored as in vitro incubation was continued. The response of embryos to vitrification and warming treatments was shown to be almost the same for both in vitro and in vivo blastocysts, though the former were significantly (p < 0.05) less tolerant of exposure to vitrification solution. These results suggest that in vitro blastocysts were much more susceptible to vitrification solution than in vivo blastocysts. The degree of damage caused by vitrification and thawing treatments, and the inhibition of in vitro embryonic development, were significantly (p < 0.05) more serious for in vitro blastocysts.
Ultrastructural studies of early mouse embryos obtained by oocyte fusion
Authors: Nogués Carme , ponsà Montserrat , Egozcue Josep , Vidal Francesa 
Published: September 2008

SummaryOocyte fusion induced by inactivated Sendai virus results in the production of ‘zygotes’that are able to undergo the first stages of embryonic development. The oocyte fusion products (OFP) obtained follow a morphological developmental pattern equivalent to that of control embryos, at least up to the 8-cell stage. The percentage of OFP that reach the 8-cell stage is extremely low(3%)compared with control embryos culturedin vitro(95%). On light microscopy, the OFP obtained show morphological characteristics identical to control embryos, although their cell diameters are larger. The cortical reaction, meiotic reactivation, extrusion of second polar bodies and pronucleus formation take place as observed in controls. The ultrastructural characteristics of oocyte fusion products at the 1-2-4- and 8- cell stages are analogous to those of controls, including the presence of structures related to the activation of the embryo genome. However some differences concerning cell ultrastructure, mainly in the nucleus, are observed and discussed in the text.
Isolation and microinjection of active sperm nuclei into egg cells and central cells of isolated maize embryo sacs
Authors: Matthys-Rochon E. , Mòl R. , Heizmann P. , Dumas C. 
Published: September 2008

SummaryArtificial fertilisation was attempted in maize by microinjecting sperm nuclei into the egg cell or central cell of isolated embryo sacs. A protocol for isolation of nuclei from pollen grains was developed and a pure fraction of sperm nuclei was obtained after centrifugation on a Percoll gradient. The in vitro transcriptional activity of the nuclei was tested by incorporation of radioactive UTP into RNA. The level of labelled nucleotide incorporation increased and reached a maximum after between 30 and 40 min in the incubation medium. The embryo sacs were enzymatically isolated and their viability determined by observation of cytoplasmic streaming in the female cells. The embryo sacs were immobilised by embedding in low-melting-point agarose and a single male nucleus was injected with a bevelled microcapillary. The presence of the injected nucleus in the egg or central cell was demonstrated using a cytological approach. This paper presents an alternative method for studying the intimate processes of fertilisation in plants.
Mammalian follicle-stimulating hormone stimulates DNA synthesis in secondary spermatogonia and Sertoli cells in organ culture of testes fragments from the newt,Cynops pyrrhogaster
Authors: Ji Zai Si , Abeé Shin-Ichi 
Published: September 2008

SummaryWe previously showed in organ culture of testes fragments fromCynops pyrrhogasterthat mammalian folicle-stimulating hormone (FSH) stimulates secondary spermatogonia to differentiate into primary spermatocytes. In this report, we demonstrate in organ culture that FSH stimulates DNA synthesis in secondary spermatogonia and Sertoli cells: the numbers of secondary spermatogonia and Sertoli cells incorporating 5-bromo-2′ -deoxyuridine (BrdU)throughout the culture period in the presence of FSH were 3-5 times those incorporating BrdU in the absence of FSH. Moreover, addition of FSH, induced after a day a remarkable increase in the number of spermatogonia and Sertoli cells incorporating BrdU. The above results indicate that FSH stimulates and induces DNA synthesis in spermatogonia and Sertoli cells. Most of the spermatogonia within a cyst were labelled simultaneously and at the same density, indicating that they underwent synchronous DNA synthesis, whereas all the Sertoli cells within a cyst were not labelled simultaneously, indicating that they synthesised DNA asynchronously. When testes fragments pulse-labelled with Brdu were cultured in FSH for 14 days, the secondary spermatogonia differentiated into primary spermatocytes, whereas in the absence of FSH they failed to differentiate and most died by the 7th day. The above results together show that FSH is required for the proliferation of both secondary spermatogonia and Sertoli cells as well as the differentiation of secondary spermatogonia into primary spermatocytes.
Confocal microscopy of F-actin distribution inXenopusoocytes
Authors: Roeder Amy D. , Gard David L. 
Published: September 2008

SummaryWe have used rhodamine-conjugated phalloidin and confocal microscopy to examine the organisation of filamentous actin (F-actin) during oogenesis inXenopus laevis. F-actin was restricted to a thin shell in the cortex of oogonia and post-mitotic oocytes less than 35 μm in diameter. In oocytes with diameters of 35–50 μm F-actin was observed in three cellular domains: in the cortex, in the germinal vesicle (GV) and in a network of cytoplasmic cables. Initially, actin cables were sparsely distributed in the cytoplasm, with no evidence of discrete organising centres. In larger stage I oocytes, a dense network of actin cables extended throughout the cytoplasm, linking the GV and mitochondrial mass to the cortical actin shell. Apart from the F-actin associated with the mitochondrial mass, no evidence of a polarised distribution of F-actin was apparent in stage I oocytes. F-actin was observed also in the cortex and the GV of stage VI oocytes, and a network of cytoplasmic cables surrounded the GV. Cytoplasmic actin cables extended from the GV to the animal cortex, and formed a three-dimensional network surrounding clusters of yolk platelets in the vegetal cytoplasm. Finally, disruption of F-actin in stage VI oocytes with cytochalasin resulted in distortion and apparent rotation of the GV in the animal hemisphere, suggesting that actin plays a role in maintaining the polarised organisation of amphibian oocytes.
Sperm entry into fertilised mouse eggs
Authors: Maluchnik Darek , Borsuk Ewa 
Published: September 2008

SummaryWe have investigated the oolemma block to polyspermy in the mouse. Zona-free and zona-intact eggs were fertilised and subsequently re-inseminated (the latter following zona pellucida removal). The ‘perivitelline’ block to polyspermy in zona-intact eggs renders motile sperm in the perivitelline space unable to bind to the oolemma. This is not connected with irreversible changes in the egg plasma membrane, because freshly added sperm can still fuse with such eggs freed from the zona. Fertilised eggs eventually lose the ability to fuse with sperm within 1 h, while still being able to bind many sperm.
Producing exposed cota-free embryos
Authors: Daily Michael F. , Latham Virginia H. , Garcia Claudia M. , Hockman Cynthia L. , Chun Helen , Oppenheimer Mark L. , West Steven P. , Rostamiany Karolin , Chao Richard L.C. , Pollock Edward G. , Oppenheimer Steven B. 
Published: September 2008

SummaryProduction of embryos that are free of tough outer coats facilitates studies that are not possible with embryos surrounded by impenetrable envelopes. This report describes a new procedure for preventing formation of fertilisation membranes in the sea urchin (Lytechinus pictus) model. This procedure involves treating unfertilised eggs with the enzyme alpha-amylase, which cleaves alpha-1,4 glucosidic bonds in the vitelline layer. A major advantage of this method is that it is very well defined and completely controllable with alpha-amylase inhibitor. The results suggest that intact alpha-1,4 glucosidic bonds are essential for vitelline layer integrity required for formation of the fertilisation membrane. Eggs treated with alpha-amylase possessed the same surface lectin receptors as untreated eggs and, as shown by light and transmission electron microscopy, produced healthy, cleaving embryos that were free of fertilisation envelopes.
Plasminogen activatior inhibitor type 1 in rat spermatozoa: localisation in the tail, in the acrosome and on the surface of the head
Authors: Manske Marianne , Welte Beate , Hitschke Karen , Wack Andreas , Bade Ernesto G. 
Published: September 2008

SummaryIsolated seminiferous tubules of rat testis contain considerable urokinase-inhibiting activity. An immunohistological analysis revealed the presence of plasminogen activator inhibitor type 1 (PAI-1) in the basement membrane as well as in the interior of the tubules. Distribution and intensity of the intratubular immunoreactivity depends on the tubules. Distribution and intensity of the intratubular immunoreactivity depends on the stage of the seminiferous cycle. A relatively weak signal is present around elongated nuclei of spermatids at the beginning of chromatin condensation. The signal intensity increases in the course of differentiation until a maximum is reached at stages VII-VIII. In these stages PAI-1 immunoreactivity is localised around the nuclei of the late spermatids as well as along their tails. Spermatozoa in the ductus epididymis also strongly react with the PAI-1-specific antiserum, suggesting that the inhibitor remains associated with the germ cells after spermiation and during maturation in the epididymis. In intact mature spermatozoa isolated from epididymis cauda by ‘swimming-up’ in non-capacitation medium, PAI-1 antigen is localised on the plasma membrane surrounding the head. In addition, in fixed and permeabilised cells the immunoreactivity is detectable in the acrosome and in the tail. Possible functions of PAI-1 in spermatogenesis, sperm motility and sperm-egg interaction are discussed.
Inhibition of sperm-egg fusion in the hamster and mouse by carbohydrates
Authors: Ponce Ruben H. , Urch Umbert A. , Yanagimachi Ryuzo 
Published: September 2008

SummaryAfter spermatozoa bind to and penetrate the extracellular matrix of the egg, the zona pellucida, they adhere to and fuse with the plasma membrane of the egg. Since sperm–egg fusion may involve membrane glycoproteins and/or carbohydrate binding proteins, we sought to test this hypothesis by challenging sperm–egg fusion in hamster and in mouse with added carbohydrates. In this study, a number of carbohydrate and glycoconjugates were examined for their ability to inhibit sperm–eggfusion. In the hamster, D(+)-glucosamine, D(+)-galactosamine, albumin-bovine-glucosamide and-galactosamide, fucoidan and dextran sulphate inhibited the fusion of spermatozoa with zona-free eggs. The same effects were seen in the mouse, except for the toxic effects of D(+)-galactosamine. These facts suggest a role of carbohydrate binding proteins or glycoproteins in the fertilisation process at the level of binding to and fusing with the oolemma.
Transcription of paternal Y-linked genes in the human zygote as early as the pronucleate stage
Authors: Ao Asangla , Erickson Robert P. , Winston Robert M.L. , Handysude Alan H 
Published: September 2008

SummaryGlobal activation of the embryonic genome occurs at the 4– to 8–cell stage in human embryos and is marked by continuation of early cleavage divisions in the presence of transcriptional inhibitors. Here we demonstrate, using recerse transcripase–polymerase chin reaction (Rt–PCR), the presence of transcripts for wo paternal Y chromosomal genes,ZFYandSRYin human preimplantation embryos.ZFYtranscripts were detected as early as the pronucleate stage, 20–24 h post-inseminationIn vitroand at intermediate stages up to the blastocyst stage.SRYTranscripts were also detected at 2–cell to blastocyos observed in many mammalian species focuses attention on the role of events in six determination prior to gonad differentiation.
Expression of the cell cycle control protein cdc25 in cleavage stage bovine embryos
Authors: Jones J.M. , First N.L. 
Published: September 2008

SummaryWe have examined the synthesis and expression of a homologue of the cell cycle protein cdc25 by early cleavage stage bovine embryos. cdc25 is the protein phosphatase responsible for activating p34cdc2 by dephosphorylating the threonine 14 (Thr 14) and tyrosine 15 (Tyr 15) residues of p34cdc2. Human cdc25 antibody was utilised in western blots immunoprecipitations to examine the presence and synthesis of cdc25 in bovine embryos. cdc25 is present as a 52 kDa non-phosphorylated and a 66 kDa presumably phosphorylated form in bovine 1−, 2−, 4− and 8−cell embryos. However, cdc25 is actively synthesised only in 8-Cell embryos, indicating that the cdc25 present prior to this stage is inherited from the oocyte. In addition, the synthesis of cdc25 was induced in 2-cell embryos in which cleavage was blocked with the DNA synthesis inhibitor aphidicolin.