Does residential context matter? Neighborhood migrant concentration and citizenship acquisition in the Netherlands

Published online: 12 December 2022Existing studies analyzing the relation between immigrants’ residential environment and their propensity to naturalize produce contradictory findings. These results are difficult to interpret, as studies typically do not measure residential characteristics at a sufficiently fine-grained scale to test hypotheses about social networks and naturalization, do not model the data’s multi-level structure appropriately, and do not account for selection into the residential environment. To address these shortcomings, this article draws on longitudinal micro-data from administrative registers at the neighborhood level in the Netherlands (approximately 1300 residents per neighborhood). We employ a stratified Cox proportional hazard model with shared frailty and inverse probability of treatment weighting to reduce bias due to self-selection into neighborhoods and draw on proxies of social networks in such areas. Our analyses provide support for the ‘migrant enclosure hypothesis,’ as we find that greater migrant concentration in the neighborhood is associated with lower naturalization rates and largely driven by the density of migrant social networks in those residential areas. In the Dutch context, this negative effect of migrant enclosure is especially prevalent among the large, long-settled migrant communities from Morocco and Turkey. We also find support for the ‘naturalization diffusion hypothesis’ and observe that the negative naturalization effect of residing in neighborhoods with higher levels of migrant concentration is offset by the presence of immigrants who have completed the naturalization procedure. Together, these findings reveal a nuanced picture that contrasts with de-contextualized cost-benefit theories of immigrant naturalization and highlights the relevance of the local context of immigrant settlement

In situ reduction of charge noise in GaAs/AlGaAs Schottky-gated devices

We show that an insulated electrostatic gate can be used to strongly suppress ubiquitous background charge noise in Schottky-gated GaAs/AlGaAs devices. Via a 2-D self-consistent simulation of the conduction band profile we show that this observation can be explained by reduced leakage of electrons from the Schottky gates into the semiconductor through the Schottky barrier, consistent with the effect of "bias cooling". Upon noise reduction, the noise power spectrum generally changes from Lorentzian to $1/f$ type. By comparing wafers with different Al content, we exclude that DX centers play a dominant role in the charge noise.Comment: 4 pages, 3 figure

The hard X-ray and Ti-44 emission of Cas A

We present an analysis of the BeppoSAX high X-ray energy spectrum of the supernova remnant Cassiopeia A with an observation time of 83 ks. We measure a flux upper limit of 4.1E-5 ph/cm^2/s (99.7% confidence) of the nuclear decay lines of Ti-44 at 68 keV and 78 keV that is lower and inconsistent with the flux of an accompanying line at 1157 keV measured by CGRO's Comptel. However, if the underlying X-ray continuum is lower, because the spectrum is steepening, the actual Ti-44 flux may be higher and consistent with the Comptel result, although the measured flux of (2.9 +/- 1.0)E-5 ph/cm^2/s under this assumption is still lower than the flux measured by Comptel.Comment: ; JVs present address: AIP, Potsdam ([email protected]). To be published in Advances of Space Research (proc. of the Cospar Conference, Nagoya, 1998). 6 pages, 3 figure

Inhibition of insulin- and insulin-like growth factor-I-stimulated growth of human breast cancer cells by 1,25-dihydroxyvitamin D3 and the vitamin D3 analogue EB1089

1, 25 Dihydroxyvitamin D3 (1,25-(OH)2D3) and a number of synthetic vitamin D3 analogues with low calcaemic activity, have been shown to inhibit breast cancer cell growth in vitro as well as in vivo. The purpose of the present study was to investigate a possible interaction of 1, 25-(OH)2D3 and the vitamin D3 analogue EB1089 with the insulin-IGF-I regulatory system. The oestrogen receptor-positive MCF-7 human breast cancer cells used in this study are able to grow autonomously and their growth is stimulated by insulin. In order to avoid interference of IGF-binding proteins (IGF-BPs), we used an analogue of IGF-I, long R3 IGF-I, which stimulated MCF-7 cell growth similar to insulin. The growth stimulation by insulin and by long R3 IGF-I was completely inhibited by 1,25-(OH)2D3 and EB1089. Autonomous growth was also inhibited by 1,25-(OH)2D3 and EB1089. The analogue EB1089 was active at 50 times lower concentrations than 1,25-(OH)2D3. It was shown that growth inhibition was not achieved through downregulation of insulin and IGF-I binding after 48 h. Paradoxically, after prolonged treatment (8 days), an upregulation of insulin and IGF-I binding was observed. Two possible intracellular mediators of the insulin-IGF mitogenic signal are C-FOS and mitogen-activated protein (MAP) kinase. Insulin-induced C-FOS mRNA was inhibited by 1,25-(OH)2D3, suggesting that it could be involved in the growth inhibition by 1,25-(OH)2D3. MAP kinase activation appeared not to be involved in growth stimulation by both insulin and IGF-I. Together, the present study demonstrates that vitamin D3 compounds can block the mitogenic activity of insulin and IGF-I, which may contribute to their tumour suppressive activity observed in vivo. Copyrigh

Combined brain-derived neurotrophic factor and neurotrophin-3 treatment is preferred over either one separately in the preservation of the auditory nerve in deafened guinea pigs

Severe hearing loss or deafness is often caused by cochlear hair cell loss and can be mitigated by a cochlear implant (CI). CIs target the auditory nerve, consisting of spiral ganglion cells (SGCs), which degenerate gradually, following hair cell loss. In animal models, it has been established that treatment with the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) reduce SGC degeneration. In this study, we aimed to investigate whether treatment with both BDNF and NT-3 (Cocktail) is superior to treatment with each neurotrophin separately regarding cell preservation and neural responsiveness to electrical stimulation. To this end, deafened guinea pigs received neurotrophic treatment in their right ear via a gelatin sponge on the perforated round window membrane, followed by cochlear implantation 4 weeks later in the same ear for electrophysiological recordings to various stimulation paradigms. Normal-hearing and deafened untreated guinea pigs were included as positive and negative controls, respectively. Substantial SGC loss occurred in all deafened animals. Each of the neurotrophic treatments led to enhanced SGC survival mainly in the basal turn of the cochlea, gradually decreasing toward the apex. The Cocktail treatment resulted in the highest SGC survival in the treated ear, followed by BDNF, with the least protection of SGCs following NT-3 treatment. Survival of the SGC's peripheral processes (PPs) followed the same trend in response to the treatment. However, survival of SGCs and PPs in the contralateral untreated ears was also highest in the Cocktail group. Consequently, analysis of the ratio between the treated and untreated ears showed that the BDNF group, which showed low SGC survival in the untreated ear, had the highest relative SGC survival of the three neurotrophin-treated groups. Neurotrophic treatment had positive effects in part of the electrically evoked compound action-potential recording paradigms. These effects were only observed for the BDNF or Cocktail treatment. We conclude that treatment with either BDNF or a cocktail of BDNF and NT-3 is preferred to NT-3 alone. Furthermore, since the Cocktail treatment resulted in better electrophysiological responsiveness and overall higher SGC survival than BDNF alone, we are inclined to recommend the Cocktail treatment rather than BDNF alone