bluuebunny/crossref_metadata_2025_split huggingface dataset:
Consonant clusters in child phonology and the directionality of syllable structure assignment
Authors: Lleó Conxita , Prinz Michael 
Published: September 2008

ABSTRACTThe production of target consonant clusters at early stages of acquisition is analysed from a phonological representational perspective. The data stem from five normal monolingual German and four normal monolingual Spanish children at ages from 0;9 to 2;1, observed in naturalistic settings. At the beginning stages, target clusters are reduced to a single consonantal position, due to lack of branching of the syllabic constituents. This finding coincides with other results in the literature, which have in general been explained by means of universal principles. Nevertheless, there is an essential difference between the German and the Spanish data: German children tend to prefer the first consonant and Spanish children the second one. This difference can only be explained in terms of parameterization of syllabification, which in German takes place from left to right and in Spanish from right to left. At later stages, when clusters begin to be produced with two consonantal positions, they offer evidence for the beginning of branching of syllabic constituents, due to parameterization, and for the chronological order of the setting of the subsyllabic parameters. Our data offer evidence in favour of the following acquisitional hierarchy: CV > CVC > CVCC > CCVCC.
Eighteen-month-old children learn words in non-ostensive contexts
Authors: Tomasello Michael , Strosberg Randi , Akhtar Nameera 
Published: September 2008

ABSTRACTPrevious studies have demonstrated that children aged 2;0 can learn new words in a variety of non-ostensive contexts. The current two studies were aimed at seeing if this was also true of children just beginning to learn words at 1;6. In the first study an adult interacted with 48 children. She used a nonce word to announce her intention to find an object (‘Let's find the gazzer’), picked up and rejected an object with obvious disappointment, and then gleefully found the target object (using no language). Children learned the new word as well in this condition as in a condition in which the adult found the object immediately. In the second study the adult first played several rounds of a finding game with each of 60 children, in which it was first established that one of several novel objects was always in a very distinctive hiding place (a toy barn). The adult then used a nonce word to announce her intention to find an object (‘Let's find the toma’) and then proceeded to the barn. In the key condition the barn was mysteriously ‘locked’; the child thus never saw the target object after the nonce word was introduced. Children learned the new word as well in this condition as in a condition in which the adult found the object immediately. The results of these two studies suggest that from very early in language acquisition children learn words not through passive, associative pro- cesses, but rather through active attempts to understand adult behaviour in a variety of action and discourse contexts.
Competition on the face: affect and language in ASL motherese
Authors: Reilly Judy Snitzer , Bellugi Ursula 
Published: September 2008

ABSTRACTResearch on early mother-child interaction has documented the crucial role affect plays in the content and modulation of early interactions. For hearing mothers, voice quality is considered to be the single most informative channel for affective expression. For deaf caregivers who use American Sign Language (ASL), the vocal channel is unavailable, and facial expression is critically important. Not only do facial behaviours signal affective and communicative information, but specific facial behaviours also function as obligatory grammatical markers. This multifunctionality of facial expression presents a dilemma for deaf parents signing to their toddlers as these two systems potentially compete for expression on the face. This study addresses how affective facial expression interacts with the linguistic forms in ASL motherese. To address this issue, we present data from both cross-sectional and longitudinal videotaped interaction from a total of 15 deaf mothers signing with their deaf toddlers (ages 0;9–2;8). Using Ekman & Friesen's Facial Action Coding System (FACS) (1978) we analysed child-directed maternal wh- questions. Because they are frequent in early discourse, AND they require furrowed brows which also signal anger and puzzlement, wh- questions represent an ideal context to address the potential conflict of grammatical and affective facial expression in ASL motherese. Our studies indicate a shift from affect to grammar at about the child's second birthday. These findings shed new insight on the nature and possible role of input on the language acquisition process.
An outbreak of hepatitis A in recently vaccinated students from ice snacks made from contaminated well water
Authors: ZHANG L. J. , WANG X. J. , BAI J. M. , FANG G. , LIU L. G. , ZHANG Y. , FONTAINE R. E. 
Published: September 2008

SUMMARYOn 30 May 2006, township S in Sichuan Province, China, reported an outbreak of hepatitis A (HA) in students who had recently received HA vaccine. The concern was raised that the vaccine had caused the outbreak. We attempted to identify the source of infection and mode of transmission. A HA case was defined as onset of jaundice or anorexia since 1 April 2006 with a twofold elevation of alanine aminotransferase (ALT) and anti-HA virus-IgM in a resident of or visitor to the township. Exposures to vaccine and snacks of 90 case-students to those of 107 control-students were compared. Thirty-four per cent of cases ate ice slush compared to 4·7% of controls (OR 4·1), and 51% of cases ate snow cones compared to 17% of controls (OR 8·3). The ice snacks were made with well water. HA virus RNA was detected by reverse transcription–polymerase chain reaction from patients' blood and well water. Untreated well water poses important dangers to the public in areas where piped, potable water is available.
LargeSalmonellaEnteritidis outbreak with prolonged transmission attributed to an infected food handler, Texas, 2002
Authors: BEATTY M. E. , SHEVICK G. , SHUPE-RICKSECKER K. , BANNISTER E. , TULU A. , LANCASTER K. , ALEXANDER N. , ZELLNER D. E. , LYSZKOWICZ E. , BRADEN C. R. 
Published: September 2008

SUMMARYIn March 2002, an outbreak ofSalmonellaEnteritidis (SE) infections occurred at a convention centre in Dallas, Texas and continued for 6 weeks. We conducted epidemiological studies, obtained clinical and environmental cultures, and interviewed employees to identify risk factors for infection. From 17 March–25 April 2002, the implicated hotel kitchen catered 41 multi-day conferences attended by 9790 persons. We received 617 illness reports from residents of 46 states. Sauces or items served with sauces were implicated in three cohort studies. SE phage-type 8 was identified as the agent. Eleven food service employees, including one who prepared sauces and salsa, had stool cultures that yielded SE. Although the original source was not determined, prolonged transmission resulted in the largest food handler-associated outbreak reported to date, affecting persons from 46 US states. Transmission ended with implementation of policies to screen food handlers and exclude those whose stool cultures yielded salmonellas.
Thermal runaway in a non-local problem modelling Ohmic heating: Part I: Model derivation and some special cases
Authors: Lacey A. A. 
Published: September 2008

We consider the non-local problemwhich models the temperature when an electric current flows through a material with temperature dependent electrical resistivity f(u) > 0, subject to a fixed potential difference. It is found that for some special cases where f is decreasing andso the problem can be scaled to makethen:(a) for λ < 8 there is a unique steady state which is globally asymptotically stable: (b) for λ = 8 there is no steady state and u is unbounded; (c) for λ > 8 there is no steady state and u blows up for all x, – 1 < x < 1.
On nonclassical invertible transformations of hyperbolic equations
Authors: Sokolov V. V. , Svinolupov S. I. 
Published: September 2008

The main result of this paper is a complete description of local invertible transformationsrelating one equation of the form uxy = F(x, y, u, ux, uy) to another equation of the form υxy = G(x, y, υ, υx, υy).
Thermal runaway in a non-local problem modelling Ohmic heating. Part II: General proof of blow-up and asymptotics of runaway
Authors: Lacey A. A. 
Published: September 2008

We consider the non-local problemIt is found that for the case of decreasingfthen: (i) forthere is a unique steady state which is globally asymptotically stable; (ii) forthen the problem can be scaled so thatin which case: (a) for λ < 8 there is a unique steady state which is globally asymptotically stable; (b) for λ = 8 there is no steady state anduis unbounded; (c) for λ > 8 there is no steady state andublows up for allx, −1 <x, < 1. Some formal asymptotic estimates for the local behaviour ofuas it blows up are obtained.
Asymptotic behaviour of functional-differential equations with proportional time delays
Authors: Liu Yunkang 
Published: September 2008

This paper discusses the initial value problemwhereA, BiandCiared × dcomplex matrices,pi,qi∈ (0, 1),i= 1, 2, …, andy0is a column vector in ℂd. By using ideas from the theory of ordinary differential equations and the theory of functional equations, we give a comprehensive analysis of the asymptotic behaviour of analytic solutions of this initial value problem.
Non-equilibrium imbibition of a porous block
Authors: Gilman Arkady 
Published: September 2008

We consider a phenomenological model proposed by Barenblatt [1] for non-equilibrium two-phase flow in porous media. In the case of zero total flow it reduces to a pair of equations:where Φ(σ) is a non-decreasing (not necessarily increasing) smooth function defined in the interval 0 ≤ σ ≤ 1. We consider initial-boundary problems for this system in which the initial data are given only for s, and the boundary data only for ς (which corresponds to the physical sense of the model). The degenerate character of the system allows us to apply simple topological methods. We show that the boundary problem is well-posed, in the sense that there exits a unique (weak) solution which satisfies the maximum principle and depends continuously on the initial data. The solution is no less smooth than the initial and boundary data.
Ratio confocal imaging of free cytoplasmic calcium gradients in polarising and polarisedFucuszygotes
Authors: Berger Frederic , Brownlee Colin 
Published: September 2008

SummaryIn the marine brown alga,Fucus, two poles are differentiated before cell division determining the future rhizoid or thallus. We have used a combination of the Ca2+-sensitive dye Calcium Green and the pH-sensitive dye SNARF monitored at pH-insensitive wavelengths to obtain confocal ratio images of free cytoplasmic calcium distribution at different stages in polarisingFucuszygotes. These dyes have the advantage that they can be used in most confocal microscopes and their longer excitation wavelengths greatly reduce autofluorescence problems. Dyes of varying molecular weights (free acid form, 10 000 mol.wt or 70 000 mol.wt dextran-conjugated) were pressure microinjected into early zygotes which were allowed to polarise in unidirectional light. Dextran-conjugated dyes remained non-compartmentalised and fluorescence could be monitored for up to 3 days following microinjection. Currently we have been able to detect Ca2+gradients at the tip of the rhizoid, confirming earlier results. Localised Ca2+elevations have also been observed at the rhizoid pole of the polarising zygote before the onset of rhizoid germination. Limitations of this technique and the significance of these Ca2+gradients are discussed.
Assessment of the cellular DNA content of whole mounted mouse and human oocytes and of blastomeres containing single or multiple nuclei
Authors: Winston Nicola J. , Johnson Martin H. , Braude Peter R. 
Published: September 2008

SummaryThe nuclear DNA content of intact, live or fixed, human and mouse oocytes and blastomeres has been measured rapidly and reliably. Chromosomal DNA has been stained with DAPI, the fluorescent emission from which has been measured photocytometrically.In vitrofertilised mouse oocytes and embryos at various stages of development were assessed for their DNA content. The mean values of 1C, 2C and 4C DNA content were clearly different, and it was possible to assign correctly individual values for DNA content to each class with 92%, 61% and 81% confidence respectively. Maintaining the cells as whole mounts allowed other morphological and structural features to be examined. When formation of multiple micronuclei was induced in mouse oocytes by their insemination in the presence of nocodazole, the additive signal from all the micronuclei in one zygote was equivalent to the expected DNA content. Application to early human blastomeres of this photocytometric technique for measurement of the total cellular DNA content revealed that multinucleated blastomeres contained 2C to 4C DNA levels, consistent with a diploid DNA content.
Bovine blastocyst development after follicle-stimulating hormone and platelet-derived growth factor treatment for oocyte maturationin vitro
Authors: Harper Kathleen M. , Brackett Benjamin G. 
Published: September 2008

SummaryBovine embryonic viability afterin vitrofertilisation (IVF) was affected by addition of platelet-derived growth factor (PDGF) or growth factor combinations to gonadotrophin-supplemented serum-free medium forin vitromaturation (IVM). Thus, 0.1, 1.0 or 10.0 ng PDGF/ml combined with 500 ng follicle-stimulating hormone (FSH)/ml enhanced oocyte maturation as reflected by greater proportions (p< 0.05) of matured and inseminated oocytes developing to blastocystsin vitrothan were afforded by PDGF alone, i.e. 32.4%, 28.2% and 31.0% respectively vs. 11.4%, 13.5% and 8.6% respectively. By contrast, luteinising hormone (LH, 500 ng/ml) combined with the same concentrations of PDGF did not increase the proportions of oocytes developing to blastocysts (16.2%, 12.5% and 16.9%). Epidermal growth factor (EGF) + insulin-like growth factor-I (IGF-I) with or without PDGF when added to low concentrations of FSH or LH did not significantly improve cleavage or morula development. Significant improvement (p& 0.05) in blastocyst formation was seen when FSH was supplemented with either EGF (38.0%) or EGF + IGF-I + PDGF (40.7%) compared with FSH alone (27.4%) or FSH + LH (24.3%), but no improvement followed FSH + EGF + IGF-I (33.6%) or FSH + LH + EGF + IGF-I + PDGF (29.2%) treatments for IVM. Results revealed a positive influence on blastocyst development of FSH and PDGF or EGF ± PDGF during IVM and suggest the possibility of a concerted action of gonadotrophins with growth factors in physiological (functional) oocyte maturation.
Thimerosal reveals calcium-induced calcium release in unfertilised sea urchin eggs
Authors: McDougall Alex , Gillot Isabelle , Whitaker Michael 
Published: September 2008

SummaryThe fertilisation calcium wave in sea urchin eggs triggers the onset of development. The wave is an explosive increase in intracellular free calcium concentrationthat begins at the point of sperm entry and crosses the egg in about 20 s. Thimerosal is a sulphydryl reagent that sensitises calcium release from intracellular stores in a variety of cell types. Treatment of unfertilised eggs with thimerosal causes a slow increasethat results eventually in a large, spontaneous calcium transient and egg activation. At shorter times after thimerosal treatment, egg activation and the calcium transient can be triggered by calcium influx through voltage-gated calcium channels, a form of calcium-induced/calcium release (CICR). Thimerosal treatment also reduces the latency of the fertilisation calcium response and increases the velocity of the fertilisation wave. These results indicate that thimerosal can unmask CICR in sea urchin eggs and suggest that the ryanodine receptor channel based CICR may contribute to explosive calcium release during the fertilisation wave.
Electrical maturation of the murine oocyte: an increase in calcium current coincides withacquisition of meiotic competence
Authors: Murnane Joan M. , DeFelice Louis J. 
Published: September 2008

SummaryWe have used the whole-cell recording technique to compare three stages of primary and secondary oocytes from F1hybrid mice (C57BL/6J x SJL/J):neonatal germinal vesicle (NGV) stage primary oocytes from 10- to 20-day-old, prepubescent mice; mature germinal vesicle (MGV) stage primary oocytes from 12-week-old, post-pubescent, superovulated mice; first polar body (FPB) stage secondary oocytes from 12-week-old, post-pubescent mice during the normal oestrus cycle or following superovulation. NGV, MGV and FPB oocytes all exhibit two voltage-dependent currents: an inward, rapidly activating/inactivating current, and an outward, slowly activating/non-inactivating current. In 1.5 mmol/1 external Ca the average peak inward current is − 2.9, − 12.4 and − 13.8 μA/cm2in NGV, MGV and FPB oocytes, respectively. In 20 mmol/1 Ca these currents increase and the reversal potential shifts to the right. The outward current decreases slightly with growth and development: at 40 mV test potentials, NGV oocytes have average outward currents of 8.9 μA/cm2, and MGV and FPB oocytes have currents of 5.0 and 5.5 μA/cm2, respectively. Thus, MGV oocytes express FPB current patterns. The reversal potentials, kinetics and pharmacology of the currents indicate that Ca channels carry the inward current and K channels carry the outward current. During growthin vivoa gradual depolarisation accompanies maturation. Resting potentialsranged from − 45 to − 30 mV in NGV oocytes to − 35 to − 17 mV in MGV oocytes to − 20 mV to − 3 mV in FPB oocytes. These data suggest that a selective increase occurs in the number of Ca channels during oocyte growth. This increase precedes nuclear maturation and coincides with the acquisition of meiotic competence.
Jelly plug dissolution in Discoglossus pictus eggs (Anura) involves peroxidase-like activity and oxidative opening of disulphide bonds
Authors: Pitari G. , Dupré S. , Fusco C. , Maurizi G. , Campanella C. 
Published: September 2008

SummaryIn amphibian eggs the formation of a capsular chamber is one of the most striking events occurring either upon oviposition or after fertilisation. In the egg of the anuran Discoglossus pictus a capsular chamber forms following fertilisation or activation; the egg with its vitelline envelope rotates in this chamber according to gravity. Previous work showed that the chamber is the product of plug dissolution. The plug is a lens-shaped jelly coat, typical of Discoglossus, covering only part of the animal hemisphere. Its dissolution is caused by material released from the egg about 15 min after fertilisation through exocytosis of at least two types of vacuoles. Liquefaction of the plug correlates with the reduction of disulphide bonds present in the jelly matrix. In this study we investigated the nature of the substances released from the egg and some changes occurring in the plug during liquefaction. SDS-PAGE showed that the proteic profile of the plug changes dramatically after fertilisation, confirming proteic cleavage in the plug matrix during its dissolution. Through in vitro tests and electrophoretic analysis of the Ringer solution in which the egg exudate was collected, an increase in the activity of the solution was determined in the presence of hydrogen peroxide, and peroxidase activity was depicted in the egg exudate. The presence of free thiol groups and cysteic acid residues (or cysteine sulphinic acid) in the plugs of activated eggs was established, suggesting that during plug dissolution some disulphide bonds are oxidatively opened. This suggests that enzyme(s) with peroxidase activity are released following fertilisation. We surmise that such enzymes are contained in the intraovular vacuoles the exocytosis of which triggers the onset of plug liquefaction. The possible release of hydrogen peroxide from the egg is discussed.
Evidence that acrosin activity is important for the development of fusibility of mammalian spermatozoa with the oolemma: inhibitor studies using the golden hamster
Authors: Takano Hiroko , Yanagimachi R. , Urch Umbert A. 
Published: September 2008

SummaryThe sperm plasma membrane over the equatorial segment of the acrosome gains the ability to fuse with the oolemma some time during, or after, the acrosome reaction. Since acrosin is a major component of the acrosome matrix that dissolves during the acrosome reaction, we sought to determine the effect of acrosin inhibitors on the sperm's ability to fuse with the oolemma. Five acrosin inhibitors (soybean trypsin inhibitor (SBTI), leupeptin, benzamidine,N-p-tosyl-1-lysin-chloromethyl ketone (TLCK) and phenylmethylsulphonyl fluoride (PMSF) and one non-acrosin inhibitor (N-p-tosyl-1-phenylalanine chloromethyl ketone (TPCK) were tested at non-toxic levels (below motility-disturbing concentrations). These inhibitors were added at three different times: (1) during the acrosome reaction of spermatozoa, (2) during sperm-oocyte contact and fusion, and (3) soon after sperm-oocyte fusion was completed. TLCK prevented sperm-oocyte fusion by inhibiting the acrosome reaction.PMSF inhibited gamete fusion, without inhibiting the acrosome reaction. SBTI, leupeptin and benzamidine also inhibited gamete fusion, but they had no effect if spermatozoa were allowed to acrosome-react in inhibitor-free medium. TPCK was without any inhibitory effects, suggesting that chymotrypsin-like enzymes are not involved in gamete fusion. Although acrosin inhibitors prevented acrosome-reacted spermatozoa from becoming fusion-competent, acrosin (and trypsin) alone could not make the plasma membrane of acrosome-intact spermatozoa fusion-competent. The data suggest that (1) the plasma membrane of the acrosomal region first undergoes dramatic changes immediately before or during the acrosome reaction and (2) acrosin released from the acrosome during the acrosome reaction further alters biophysical and biochemical characteristics of the plasma membrane over the equatorial segment. Such dual changes make the plasma membrane of this specialised region of the spermatozoon competent to fuse with the oolemma. Acrosin may not be the only acrosomal enzyme to participate in these changes.
Ultrastructural changes ofArabidopsis thalianapollen during final maturation and rehydration
Authors: Van Aelst A.C. , Pierson E.S. , Van Went J.L. , Cresti M. 
Published: September 2008

SummarySeveral ultrastructural changes occur during dehydration and subsequent rehydration ofArabidopsis thalianapollen. The cytoplasmic channels, present in the outer part of the intine of the mature, dehydrating pollen grain, degenerate and develop into electron-dense inclusions. At the same time a large quantity of electron-dense material is deposited in the cavities of the exine. A large number of vesicles is produced in the vegetative cell, and they become predominantly located in the peripheral region near the intine. Starch of amyloplasts is consumed and the lipid bodies which originally surround the sperm cells become randomly distributed. In addition, the individual lipid bodies become enveloped by single rough endoplasmic reticulum cisterns.