539 research outputs found
Bilingual Preschoolers ’ Speech is Associated with Non-Native Maternal Language Input
Published online: 11 Nov 2018Bilingual children are often exposed to non-native speech through their parents. Yet, little is known about the relation between bilingual preschoolers’ speech production and their speech input. The present study investigated the production of voice onset time (VOT) by Dutch-German bilingual preschoolers and their sequential bilingual mothers. The findings reveal an association between maternal VOT and bilingual children’s VOT in the heritage language German as well as in the majority language Dutch. By contrast, no input-production association was observed in the VOT production of monolingual German-speaking children and monolingual Dutch-speaking children. The results of this study provide the first empirical evidence that non-native and attrited maternal speech contributes to the often-observed linguistic differences between bilingual children and their monolingual peers
A SILAC-based Approach Identifies Substrates of Caspase-dependent Cleavage upon TRAIL-induced Apoptosis
The extracellular ligand-induced extrinsic pathway of apoptosis is executed via caspase protease cascades that activate downstream effectors by means of site-directed proteolysis. Here we identify proteome changes upon the induction of apoptosis by the cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a Jurkat T cell line. We detected caspase-dependent cleavage substrates by quantifying protein intensities before and after TRAIL induction in SDS gel slices. Apoptotic protein cleavage events are identified by a characteristic stable isotope labeling with amino acids in cell culture (SILAC) ratio pattern across gel slices that results from differential migration of the cleaved and uncleaved proteins. We applied a statistical test to define apoptotic substrates in the proteome. Our approach identified more than 650 of these cleaved proteins in response to TRAIL-induced apoptosis, including many previously unknown substrates and cleavage sites. Inhibitor treatment combined with triple SILAC demonstrated that the detected cleavage events were caspase dependent. Proteins located in the lumina of organelles such as mitochondria and endoplasmic reticulum were significantly underrepresented in the substrate population. Interestingly, caspase cleavage is generally observed in not only one but several members of stable complexes, but often with lower stoichiometry. For instance, all five proteins of the condensin I complex were cleaved upon TRAIL treatment. The apoptotic substrate proteome data can be accessed and visualized in the MaxQB database and might prove useful for basic and clinical research into TRAIL-induced apoptosis. The technology described here is extensible to a wide range of other proteolytic cleavage events
Feature generalization in Dutch–German bilingual and monolingual children’s speech production
First Published November 29, 2021Dutch and German employ voicing contrasts, but Dutch lacks the ‘voiced’ dorsal plosive /ɡ/. We exploited this accidental phonological gap, measuring the presence of prevoicing and voice onset time durations during speech production to determine (1) whether preliterate bilingual Dutch–German and monolingual Dutch-speaking children aged 3;6–6;0 years generalized voicing to /ɡ/ in Dutch; and (2) whether there was evidence for featural cross-linguistic influence from Dutch to German in bilingual children, testing monolingual German-speaking children as controls. Bilingual and monolingual children’s production of /ɡ/ provided partial evidence for feature generalization: in Dutch, both bilingual and monolingual children either recombined Dutch voicing and place features to produce /ɡ/, suggesting feature generalization, or resorted to producing familiar /k/, suggesting segment-level adaptation within their Dutch phonological system. In German, bilingual children’s production of /ɡ/ was influenced by Dutch although the Dutch phoneme inventory lacks /ɡ/. This suggests that not only segments but also voicing features can exert cross-linguistic influence. Taken together, phonological features appear to play a crucial role in aspects of bilingual and monolingual children’s speech production.This work was supported by the Basque Government [BERC 2018-2021 program]; the Spanish
State Research Agency [BCBL Severo Ochoa excellence accreditation SEV-2015-0490]; the
European Union’s Horizon 2020 research and innovation program [Marie Skłodowska-Curie grant
843533]; and the National Science Foundation [BCS1349110; OISE 1545900]
IPD—the Immuno Polymorphism Database
The Immuno Polymorphism Database (IPD) (http://www.ebi.ac.uk/ipd/) is a set of specialist databases related to the study of polymorphic genes in the immune system. IPD currently consists of four databases: IPD-KIR, contains the allelic sequences of Killer-cell Immunoglobulin-like Receptors; IPD-MHC, a database of sequences of the Major Histocompatibility Complex of different species; IPD-HPA, alloantigens expressed only on platelets; and IPD-ESTAB, which provides access to the European Searchable Tumour Cell-Line Database, a cell bank of immunologically characterized melanoma cell lines. The IPD project works with specialist groups or nomenclature committees who provide and curate individual sections before they are submitted to IPD for online publication. The IPD project stores all the data in a set of related databases. Those sections with similar data, such as IPD-KIR and IPD-MHC share the same database structure. The sharing of a common database structure makes it easier to implement common tools for data submission and retrieval. The data are currently available online from the website and ftp directory; files will also be made available in different formats to download from the website and ftp server. The data will also be included in SRS, BLAST and FASTA search engines at the European Bioinformatics Institute
The Milky Way's satellite population in a LambdaCDM universe
We compare the structure and kinematics of the 11 known satellites of the
Milky Way with high resolution simulations of the formation of its dark halo in
a LambdaCDM universe. In contrast to earlier work, we find excellent agreement.
The observed kinematics are exactly those predicted for stellar populations
with the observed spatial structure orbiting within the most massive
``satellite'' substructures in our simulations. Less massive substructures have
weaker potential wells than those hosting the observed satellites. If there is
a halo substructure ``problem'', it consists in understanding why halo
substructures have been so inefficient in making stars. Suggested modifications
of dark matter properties (for example, self-interacting or warm dark matter)
may well spoil the good agreement found for standard Cold Dark Matter.Comment: 5 pages, 2 figures, replaced with version accepted by MNRAS (minor
changes
Wavelength dependent ac-Stark shift of the 1S0 - 3P1 transition at 657 nm in Ca
We have measured the ac-Stark shift of the 4s2 1S0 - 4s4p 3P1 line in 40Ca
for perturbing laser wavelengths between 780 nm and 1064 nm with a time domain
Ramsey-Borde atom interferometer. We found a zero crossing of the shift for the
mS = 0 - mP = 0 transition and \sigma polarized perturbation at 800.8(22) nm.
The data was analyzed by a model deriving the energy shift from known
transition wavelengths and strengths. To fit our data, we adjusted the Einstein
A coefficients of the 4s3d 3D - 4s4p 3P and 4s5s 3S - 4s4p 3P fine structure
multiplets. With these we can predict vanishing ac-Stark shifts for the 1S0 m =
0 - 3P1 m = 1 transition and \sigma- light at 983(12) nm and at 735.5(20) nm
for the transition to the 3P0 level.Comment: 8 pages, 5 figures, 2 table
A New Approach to the Study of Stellar Populations in Early-Type Galaxies: K-band Spectral Indices and an Application to the Fornax Cluster
New measurements of K-band spectral features are presented for eleven
early-type galaxies in the nearby Fornax galaxy cluster. Based on these
measurements, the following conclusions have been reached: (1) in galaxies with
no signatures of a young stellar component, the K-band Na I index is highly
correlated with both the optical metallicity indicator [MgFe]' and central
velocity dispersion; (2) in the same galaxies, the K-band Fe features saturate
in galaxies with sigma > 150 km/s while Na I (and [MgFe]') continues to
increase; (3) [Si/Fe] (and possibly [Na/Fe]) is larger in all observed Fornax
galaxies than in Galactic open clusters with near-solar metallicity; (4) in
various near-IR diagnostic diagrams, galaxies with signatures of a young
stellar component (strong Hbeta, weak [MgFe]') are clearly separated from
galaxies with purely old stellar populations; furthermore, this separation is
consistent with the presence of an increased number of M-giant stars (most
likely to be thermally pulsating AGB stars); (5) the near-IR diagrams discussed
here seem as efficient for detecting putatively young stellar components in
early-type galaxies as the more commonly used age/metallicity diagnostic plots
using optical indices (e.g Hbeta vs. [MgFe]').Comment: 47 pages, 16 figures, ApJ accepte
Substructures in Cold Dark Matter Haloes
We analyse the properties of substructures within dark matter halos
(subhalos) using a set of high-resolution numerical simulations of the
formation of structure in a Lambda-CDM Universe. Our simulation set includes 11
high-resolution simulations of massive clusters as well as a region of mean
density, allowing us to study the spatial and mass distribution of
substructures down to a mass resolution limit of 10^9 h^(-1)Mo. We also
investigate how the properties of substructures vary as a function of the mass
of the `parent' halo in which they are located. We find that the substructure
mass function depends at most weakly on the mass of the parent halo and is well
described by a power-law. The radial number density profiles of substructures
are steeper in low mass halos than in high mass halos. More massive
substructures tend to avoid the centres of halos and are preferentially located
in the external regions of their parent halos. We also study the mass accretion
and merging histories of substructures, which we find to be largely independent
of environment. We find that a significant fraction of the substructures
residing in clusters at the present day were accreted at redshifts z < 1. This
implies that a significant fraction of present-day `passive' cluster galaxies
should have been still outside the cluster progenitor and more active at z~1.Comment: 13 pages, 15 figure. Accepted to MNRA
Mol. Syst. Biol.
Extra chromosome copies markedly alter the physiology of eukaryotic cells, but the underlying reasons are not well understood. We created human trisomic and tetrasomic cell lines and determined the quantitative changes in their transcriptome and proteome in comparison with their diploid counterparts. We found that whereas transcription levels reflect the chromosome copy number changes, the abundance of some proteins, such as subunits of protein complexes and protein kinases, is reduced toward diploid levels. Furthermore, using the quantitative data we investigated the changes of cellular pathways in response to aneuploidy. This analysis revealed specific and uniform alterations in pathway regulation in cells with extra chromosomes. For example, the DNA and RNA metabolism pathways were downregulated, whereas several pathways such as energy metabolism, membrane metabolism and lysosomal pathways were upregulated. In particular, we found that the p62-dependent selective autophagy is activated in the human trisomic and tetrasomic cells. Our data present the first broad proteomic analysis of human cells with abnormal karyotypes and suggest a uniform cellular response to the presence of an extra chromosome
NAD(P)H:quinone oxidoreductase 1 (NQO1) P187S polymorphism and prostate cancer risk in Caucasians
NAD(P)H:quinone oxidoreductase 1 (NQO1) catalyses the reduction of quinoid compounds to hydroquinones, preventing the generation of free radicals and reactive oxygen. A “C” to “T” transversion at position 609 of NQO1, leading to a nonsynonymous amino acid change (Pro187Ser, P187S), results in an altered enzyme activity. No NQO1 protein activity was detected in NQO1 609TT genotype, and low to intermediate activity was detected in NQO1 609CT genotype compared with 609CC genotype. Thus, this polymorphism may result in altered cancer predisposition. For prostate cancer, only sparse data are available. We therefore analyzed the distribution of the NQO1 P187S SNP (single nucleotide polymorphism) in prostate cancer patients and a healthy control group. Allelic variants were determined using RFLP analysis. Overall, 232 patients without any malignancy and 119 consecutive prostate cancer patients were investigated. The genotype distribution in our cohorts followed the Hardy–Weinberg equilibrium in cases and controls. The distribution of the NQO1 codon 187 SNP did not differ significantly between prostate cancer patients and the control group (p = 0.242). There was also no association between the allelic variants and stage or Gleason score of the tumors. The NQO1 P187S SNP was not significantly associated with an increased prostate cancer risk in our cohorts. The SNP has also no influence on histopathological characteristics of the tumors. A combined analysis of all available data from published European studies also showed no significant differences in the genotype distribution between controls and prostate cancer patients. Our data suggest a minor role of the NQO1 nucleotide 609 polymorphism in prostate carcinogenesis
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