2,371 research outputs found
Neural mechanisms of response-preparation and inhibition in bilingual and monolingual children: Lateralized Readiness Potentials (LRPs) during a nonverbal Stroop task
Inhibitory control is a core executive function (EF) skill, thought to involve cognitive 'interference suppression' and motor 'response inhibition' sub-processes. A few studies have shown that early bilingualism shapes interference suppression but not response inhibition skills, however current behavioral measures do not fully allow us to disentangle these subcomponents. Lateralized Readiness Potentials (LRPs) are centroparietal event-related potentials (ERPs) that track motor response-preparations between stimulus-presentation and behavioral responses. We examine LRPs elicited during successful inhibitory control on a nonverbal Stroop task, in 6-8 year-old bilingual (n = 44) and monolingual (n = 48) children from comparable socio-economic backgrounds. Relative to monolinguals, bilinguals showed longer and stronger incorrect-response preparations, and a more mature pattern of correct-response preparation (shorter peak-latencies), underlying correct responses on Stroop-interference trials. Neural markers of response-inhibition were comparable between groups and no behavioral differences were found between-groups on the Stroop task. Results suggest group differences in underlying mechanisms of centroparietal motor-response preparation mechanisms in this age group, contrary to what has been shown using behavioral tasks previously. We discuss neural results in the context of speed-accuracy trade-offs. This is the first study to examine neural markers of motor-responses in bilingual children.Published versio
Review: Biological imprinting: Some genetic considerations
Genetic imprinting represents one of the most puzzling, still unexplained, phenomena in genetics. Changing some agreed upon concepts and redefinition of some common traditional terms in classical genetics seems imperative for understanding the nature of imprinting, as well as for interpretation of possible mechanisms implicated in its occurrence.Keywords: Genetic imprinting; Mutations; Re-sense mutation; Epigenetic alterations; DNA methylation/demethylation; Parthenogenesis; Position-effect variegation; Post-fertilization genomic imprinting; microRNA; Chromatin modifications; Pyknon
A comparative study of high-field diamagnetic fluctuations in deoxygenated YBa2Cu3O(7-x) and polycrystalline (Bi-Pb)2Sr2Ca3O(10)
We studied three single crystals of YBa2Cu3O{7-x} with Tc= 62.5, 52, and 41
K, and a textured specimen of (Bi-Pb)2Sr2Ca2Cu3O10 with Tc=108 K, for H//c
axis. The reversible data were interpreted in terms of 2D lowest-Landau-level
fluctuation theory. The data were fit well by the 2D LLL expression for
magnetization obtained by Tesanovic etal., producing reasonable values of kappa
but larger values of dHc2/dT. Universality was studied by obtaining a
simultaneous scaling of Y123 data and Bi2223. An expression for the 2D x-axis
LLL scaling factor used to obtain the simultaneous scaling was extracted from
theory, and compared with the experimental values. The comparison between the
values of the x-axis produced a deviation of 40% which suggests that the
hypothesis of universality of the 2D-LLL fluctuations is not supported by the
studied samples. We finaly observe that Y123 magnetization data for
temperatures above obbey a universal scaling obtained for the diamagnetic
fluctuation magnetization from a theory considering non-local field effects.
The same scaling was not obbeyed by the corresponding magnetization calculated
from the two-dimensional lowest-Landau-level theory.Comment: 7 pages 5 figures, accept in Journ. Low Temp. Phy
Would Demarketing Strategies Rationalize Household Food Waste Consumption?
The objective of this research was to explore the influence of demarketing strategies on rationalization of household food waste “HFW” in the Gaza Strip “GS”, Palestine. More specifically, this paper concentrated on better understanding of the nature and meaning of demarketing, as well as identifying the factors that drive demarketing and develop a HFW demarketing model. To gather primary data, an empirical research was conducted with 326 questionnaires from the Palestinian citizens in the GS. The findings indicate that there is a relationship between independent variables (product, price, place, and promotion) and the dependent variable (the customer’s behavioral intention towards rationalization of HFW) for a number of reasons that were investigated during the research. The paper then concluded with recommendations for future academic studies and policymakers in Palestine
Array comparative genomic hybridization screening in IVF significantly reduces number of embryos available for cryopreservation
Objective
During IVF, non-transferred embryos are usually selected for cryopreservation on the basis of morphological criteria. This investigation evaluated an application for array comparative genomic hybridization (aCGH) in assessment of surplus embryos prior to cryopreservation.
Methods
First-time IVF patients undergoing elective single embryo transfer and having at least one extra non-transferred embryo suitable for cryopreservation were offered enrollment in the study. Patients were randomized into two groups: Patients in group A (n=55) had embryos assessed first by morphology and then by aCGH, performed on cells obtained from trophectoderm biopsy on post-fertilization day 5. Only euploid embryos were designated for cryopreservation. Patients in group B (n=48) had embryos assessed by morphology alone, with only good morphology embryos considered suitable for cryopreservation.
Results
Among biopsied embryos in group A (n=425), euploidy was confirmed in 226 (53.1%). After fresh single embryo transfer, 64 (28.3%) surplus euploid embryos were cryopreserved for 51 patients (92.7%). In group B, 389 good morphology blastocysts were identified and a single top quality blastocyst was selected for fresh transfer. All group B patients (48/48) had at least one blastocyst remaining for cryopreservation. A total of 157 (40.4%) blastocysts were frozen in this group, a significantly larger proportion than was cryopreserved in group A (p=0.017, by chi-squared analysis).
Conclusion
While aCGH and subsequent frozen embryo transfer are currently used to screen embryos, this is the first investigation to quantify the impact of aCGH specifically on embryo cryopreservation. Incorporation of aCGH screening significantly reduced the total number of cryopreserved blastocysts compared to when suitability for freezing was determined by morphology only. IVF patients should be counseled that the benefits of aCGH screening will likely come at the cost of sharply limiting the number of surplus embryos available for cryopreservation
Utilisation du PEG 6000 dans la détermination de l'activité biologique des tannins de certains arbustes méditerranéens
5 páginas, 2 tablas.--In Porqueddu C. (ed.), Ríos S. (ed.) . The contributions of grasslands to the conservation of Mediterranean biodiversity . Zaragoza : CIHEAM-IAMZ/CIBIO/FAO/SEEP, 2010. p. 209-213 : 12 réf., 2 tabl.: (Options Méditerranéennes : Série A. Séminaires Méditerranéens ; n. 92). 13. Meeting of the Sub-Network on Mediterranean Forage Resources of the FAO-CIHEAM International Network for the Research and Development of Pasture and Forage Crops, 2010/04/07-10, Alicante (Spain)[EN] Samples of foliage from some Tunisian shrub species (Erica arborea, Myrtus communis, Pistacia
lentiscus and Phillyrea angustifolia) harvested in summer from a semi arid grazing mountain area of Tunisia
were examined for their chemical composition and kinetics of gas production in presence and absence of
polyethylene glycol (PEG 6000). Total condensed tannin contents (TCT) were also analysed. Crude protein
(CP) content varied widely (40-93 g/kg DM) NDF content ranged from 440 g/kg DM in M. communis to 587
g/kg DM in P. lentiscus. The highest ADF content was for E. arborea (410 g/kg DM) and the lowest for M.
communis (270 g/kg DM). High levels of CT were observed in E. arborea followed by P. lentiscus, and M.
communis, whereas CT was almost absent in Ph. angustifolia. Asymptotic gas production (A), rate of gas
production (c) and gas produced at 24 h of incubation (G24) were generally low in E. arborea and high in
Ph. angustifolia. Addition of PEG to the incubation medium increased the parameters of gas production (A,
G24 and c). This increase was more noticeable in E. arborea and less detected in Ph. angustifolia. Based
on their crude protein and tannin contents, M. communis and P. angustifolia, may play an important role in
providing fodder for ruminants even during the dry season when the other forages are scarce. However the
foliage of E. arborea and P. lentiscus could have a potential nutritive value as when its tannin content is
biologically inactivated by using a tannin-binding agent.[FR] La composition chimique et la cinétique de production de gaz en présence et en absence du PEG
ont été examinées sur des échantillons de certaines espèces arbustives (Erica arborea, Myrtus communis,
Pistacea lentiscus and Phillyrea angustifolia) collectées en été sur la montagne du nord ouest (semi-aride)
de la Tunisie. Les teneurs de ces espèces en tannins condensés (TC) ont été aussi déterminées. Le
contenu en protéine brut (PB) oscille entre 40 et 93 g/kg MS Le contenu en fibre neutre digestible (FND)
varie de 440 g/kg MS (M. communis ) à 587 g/kg MS (P. lenticus). Le contenu le plus élevé en fibre acide
digestible (FAD) a été enregistré au niveau de E. arborea. Cependant les TC ont été pratiquement absents
dans le feuillage de Ph. angustifolia. La production de gaz assymptotique (A), le rythme de production de
gaz (c) et la production de gaz à 24h d'incubation (G24) ont été généralement faibles pour E. arborea et
élevés pour Ph. angustifolia. L'addition du PEG au milieu d'incubation s'est accompagnée par une
augmentation des paramètres de production de gaz (A, G24 and c). Cette élévation a été plus notable pour
E. arborea et moins détectée pour Ph. angustifolia. En se basant sur les teneurs en PB et en TC, les
feuillages de M. communis et Ph. Angustifolia pourraient jouer un rôle important dans l'approvisionnement
des aliments aux ruminants même durant la période de sécheresse lorsque les autres fourrages sont rares.
Cependant, les feuillages de E. arborea et P. lentiscus pourraient avoir une valeur nutritionnelle importante
une fois leurs tannins sont biologiquement désactivés en utilisant un agent détecteur des tannins.Peer reviewe
Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study
Background
Single embryo transfer (SET) remains underutilized as a strategy to reduce multiple gestation risk in IVF, and its overall lower pregnancy rate underscores the need for improved techniques to select one embryo for fresh transfer. This study explored use of comprehensive chromosomal screening by array CGH (aCGH) to provide this advantage and improve pregnancy rate from SET.
Methods
First-time IVF patients with a good prognosis (age <35, no prior miscarriage) and normal karyotype seeking elective SET were prospectively randomized into two groups: In Group A, embryos were selected on the basis of morphology and comprehensive chromosomal screening via aCGH (from d5 trophectoderm biopsy) while Group B embryos were assessed by morphology only. All patients had a single fresh blastocyst transferred on d6. Laboratory parameters and clinical pregnancy rates were compared between the two groups.
Results
For patients in Group A (n=55), 425 blastocysts were biopsied and analyzed via aCGH (7.7 blastocysts/patient). Aneuploidy was detected in 191/425 (44.9%) of blastocysts in this group. For patients in Group B (n=48), 389 blastocysts were microscopically examined (8.1 blastocysts/patient). Clinical pregnancy rate was significantly higher in the morphology+aCGH group compared to the morphology-only group (70.9 and 45.8%, respectively; p=0.017); ongoing pregnancy rate for Groups A and B were 69.1 vs. 41.7%, respectively (p=0.009). There were no twin pregnancies.
Conclusion
Although aCGH followed by frozen embryo transfer has been used to screen at risk embryos (e.g., known parental chromosomal translocation or history of recurrent pregnancy loss), this is the first description of aCGH fully integrated with a clinical IVF program to select single blastocysts for fresh SET in good prognosis patients. The observed aneuploidy rate (44.9%) among biopsied blastocysts highlights the inherent imprecision of SET when conventional morphology is used alone. Embryos randomized to the aCGH group implanted with greater efficiency, resulted in clinical pregnancy more often, and yielded a lower miscarriage rate than those selected without aCGH. Additional studies are needed to verify our pilot data and confirm a role for on-site, rapid aCGH for IVF patients contemplating fresh SET
Experimental observation of high field diamagnetic fluctuations in Niobium
We have performed a magnetic study of a bulk metallic sample of Nb with
critical temperature K. Magnetization versus temperature (M {\it
vs} T) data obtained for fixed magnetic fields above 1 kOe show a
superconducting transition which becomes broader as the field is increased. The
data are interpreted in terms of the diamagnetic lowest Landau level (LLL)
fluctuation theory. The scaling analysis gives values of the superconducting
transition temperature consistent with % . We search for
universal 3D LLL behavior by comparing scaling results for Nb and YBaCuO, but
obtain no evidence for universality.Comment: 5 pages, 6 figures, Accepted for publication in Phys.Rev.
Data Clustering Analysis of the Factors Affecting Palestinian Customers’ Attitudes Towards SMS Advertising
The aim of this article is to identify the factors affecting customer attitudes toward SMS advertising in the Palestinian banking sector using data clustering. A survey questionnaire was designed and distributed to collect primary data. In total 412 usable questionnaires were analyzed using data clustering. The findings reveal that relevancy, entertainment, informativeness, and creditability have positive impact on the attitudes of the Palestinian customers towards the Banks’ SMS advertising. Data clustering, however, provided empirical evidence that most of the respondents are annoyed by the SMS advertising which requires developing policies and procedures at the bank level to get the customers consent (permission) to receive SMS advertisements prior to sending them to customers
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