A Cross-cohort Description of Young People’s Housing Experience in Britain over 30 Years: An Application of Sequence Analysis

Methods. Sequence Analysis supported by Event History Analysis. Key Findings. Despite only 12 years separating both cohorts, the younger 1970 cohort exhibited very different patterns of housing including a slower progression out of the parental home and into stable tenure, and an increased reliance on privately rented housing. Returns to the parental home occurred across the twenties and into the thirties in both cohorts, although occurred more frequently and were more concentrated among certain groups in the 1970 cohort compared to the 1958 cohort. Although fewer cohort members in the 1970 cohort experienced social housing, and did so at a later age, social housing was also associated with greater tenure immobility in this younger cohort. Conclusions. The housing experiences of the younger cohort became associated with more unstable tenure (privately rented housing) for the majority. Leaving the parental home was observed to be a process, as opposed to a one-off event, and several returns to the parental home were documented, more so for the 1970 cohort. These findings are not unrelated, and in the current environment of rising house prices, collapses in the (youth) labour market and rising costs of higher education, are likely to increase in prevalence across subsequent cohorts

Cretaceous-to-recent record of elevated 3He/4He along the Hawaiian-Emperor volcanic chain

Helium isotopes are a robust geochemical tracer of a primordial mantle component in hot spot volcanism. The high 3He/4He (up to 35 RA, where RA is the atmospheric 3He/4He ratio of 1.39 × 10−6) of some Hawaiian Island volcanism is perhaps the classic example. New results for picrites and basalts from the Hawaiian-Emperor seamount chain indicate that the hot spot has produced high 3He/4He lavas for at least the last 76 million years. Picrites erupted at 76 Ma have 3He/4He (10–14 RA), which is at the lower end of the range for the Hawaiian Islands but still above the range of modern mid-ocean ridge basalt (MORB; 6–10 RA). This was at a time when hot spot volcanism was occurring on thin lithosphere close to a spreading ridge and producing lava compositions otherwise nearly indistinguishable from MORB. After the hot spot and spreading center diverged during the Late Cretaceous, the hot spot produced lavas with significantly higher 3He/4He (up to 24 RA). Although 3He/4He ratios stabilized at relatively high values by 65 Ma, other chemical characteristics such as La/Yb and 87Sr/86Sr did not reach and stabilize at Hawaiian-Island-like values until ~45 Ma. Our limited 3He/4He record for the Hawaiian hot spot shows a poor correlation with plume flux estimates (calculated from bathymetry and residual gravity anomalies [Van Ark and Lin, 2004]). If 3He is a proxy for the quantity of primordial mantle material within the plume, then the lack of correlation between 3He/4He and calculated plume flux suggests that variation in primordial mantle flux is not the primary factor controlling total plume flux

Hyperfine-field-mediated spin beating in electrostatically bound charge carrier pairs

Journal ArticleOrganic semiconductors offer a unique environment to probe the hyperfine coupling of electronic spins to a nuclear spin bath. We explore the interaction of spins in electron-hole pairs in the presence of inhomogeneous hyperfine fields by monitoring the modulation of the current through an organic light emitting diode under coherent spin-resonant excitation. At weak driving fields, only one of the two spins in the pair precesses. As the driving field exceeds the difference in local hyperfine field experienced by electron and hole, both spins precess, leading to pronounced spin beating in the transient Rabi flopping of the current. We use this effect to measure the magnitude and spatial variation in hyperfine field on the scale of single carrier pairs, as required for evaluating models of organic magnetoresistance, improving organic spintronics devices, and illuminating spin decoherence mechanisms

Differentiation between polaron-pair and triplet-exciton polaron spin-dependent mechanisms in organic light-emitting diodes by coherent spin beating

Pulsed electrically detected magnetic resonance offers a unique avenue to distinguish between polaron-pair (PP) and triplet-exciton polaron (TEP) spin-dependent recombination, which control the conductivity and magnetoresistivity of organic semiconductors. Which of these two fundamental processes dominates depends on carrier balance: by injecting surplus electrons we show that both processes simultaneously impact the device conductivity. The two mechanisms are distinguished by the presence of a half-field resonance, indicative of TEP interactions, and transient spin beating, the signature of PPs. Coherent spin Rabi flopping in the half-field (triplet) channel is observed, demonstrating that the triplet exciton has an ensemble phase coherence time of at least 60 ns, offering insight into the effect of carrier correlations on spin dephasing

Slow Hopping and Spin Dephasing of Coulombically Bound Polaron Pairs in an Organic Semiconductor at Room Temperature

Polaron pairs are intermediate electronic states that are integral to the optoelectronic conversion process in organic semiconductors. Here, we report on electrically detected spin echoes arising from direct quantum control of polaron pair spins in an organic light-emitting diode at room temperature. This approach reveals phase coherence on a microsecond time scale, and offers a direct way to probe charge recombination and dissociation processes in organic devices, revealing temperature-independent intermolecular carrier hopping on slow time scales. In addition, the long spin phase coherence time at room temperature is of potential interest for developing quantum-enhanced sensors and information processing systems which operate at room temperature

Nonparametric estimation of correlation functions in longitudinal and spatial data, with application to colon carcinogenesis experiments

In longitudinal and spatial studies, observations often demonstrate strong correlations that are stationary in time or distance lags, and the times or locations of these data being sampled may not be homogeneous. We propose a nonparametric estimator of the correlation function in such data, using kernel methods. We develop a pointwise asymptotic normal distribution for the proposed estimator, when the number of subjects is fixed and the number of vectors or functions within each subject goes to infinity. Based on the asymptotic theory, we propose a weighted block bootstrapping method for making inferences about the correlation function, where the weights account for the inhomogeneity of the distribution of the times or locations. The method is applied to a data set from a colon carcinogenesis study, in which colonic crypts were sampled from a piece of colon segment from each of the 12 rats in the experiment and the expression level of p27, an important cell cycle protein, was then measured for each cell within the sampled crypts. A simulation study is also provided to illustrate the numerical performance of the proposed method.Comment: Published in at http://dx.doi.org/10.1214/009053607000000082 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Early-type galaxies in the SDSS. II. Correlations between observables

A magnitude limited sample of nearly 9000 early-type galaxies, in the redshift range 0.01 < z < 0.3, was selected from the Sloan Digital Sky Survey using morphological and spectral criteria. The sample was used to study how early-type galaxy observables, including luminosity L, effective radius R_o, surface brightness I_o, color, and velocity dispersion sigma, are correlated with one another. Measurement biases are understood with mock catalogs which reproduce all of the observed scaling relations and their dependences on fitting technique. At any given redshift, the intrinsic distribution of luminosities, sizes and velocity dispersions in our sample are all approximately Gaussian. A maximum likelihood analysis shows that sigma ~ L^{0.25\pm 0.012}, R_o ~ L^{0.63\pm 0.025}, and R_o ~ I^{-0.75\pm 0.02} in the r* band. In addition, the mass-to-light ratio within the effective radius scales as M_o/L ~ L^{0.14\pm 0.02} or M_o/L ~ M_o^{0.22\pm 0.05}, and galaxies with larger effective masses have smaller effective densities: Delta_o ~ M_o^{-0.52\pm 0.03}. These relations are approximately the same in the g*, i* and z* bands. Relative to the population at the median redshift in the sample, galaxies at lower and higher redshifts have evolved only little, with more evolution in the bluer bands. The luminosity function is consistent with weak passive luminosity evolution and a formation time of about 9 Gyrs ago.Comment: 29 pages, 11 figures. Accepted by AJ (scheduled for April 2003). This paper is part II of a revised version of astro-ph/011034

Personal data broker instead of blockchain for students’ data privacy assurance

Data logs about learning activities are being recorded at a growing pace due to the adoption and evolution of educational technologies (Edtech). Data analytics has entered the field of education under the name of learning analytics. Data analytics can provide insights that can be used to enhance learning activities for educational stakeholders, as well as helping online learning applications providers to enhance their services. However, despite the goodwill in the use of Edtech, some service providers use it as a means to collect private data about the students for their own interests and benefits. This is showcased in recent cases seen in media of bad use of students’ personal information. This growth in cases is due to the recent tightening in data privacy regulations, especially in the EU. The students or their parents should be the owners of the information about them and their learning activities online. Thus they should have the right tools to control how their information is accessed and for what purposes. Currently, there is no technological solution to prevent leaks or the misuse of data about the students or their activity. It seems appropriate to try to solve it from an automation technology perspective. In this paper, we consider the use of Blockchain technologies as a possible basis for a solution to this problem. Our analysis indicates that the Blockchain is not a suitable solution. Finally, we propose a cloud-based solution with a central personal point of management that we have called Personal Data Broker.Peer ReviewedPostprint (author's final draft

Discovery of Four Gravitationally Lensed Quasars from the Sloan Digital Sky Survey

We present the discovery of four gravitationally lensed quasars selected from the spectroscopic quasar catalog of the Sloan Digital Sky Survey. We describe imaging and spectroscopic follow-up observations that support the lensing interpretation of the following four quasars: SDSS J0832+0404 (image separation \theta=1.98", source redshift z_s=1.115, lens redshift z_l=0.659); SDSS J1216+3529 (\theta=1.49", z_s=2.012); SDSS J1322+1052 (\theta=2.00", z_s=1.716); and SDSS J1524+4409 (\theta=1.67", z_s=1.210, z_l=0.320). Each system has two lensed images. We find that the fainter image component of SDSS J0832+0404 is significantly redder than the brighter component, perhaps because of differential reddening by the lensing galaxy. The lens potential of SDSS J1216+3529 might be complicated by the presence of a secondary galaxy near the main lensing galaxy.Comment: 25 pages, 10 figures, 6 tables, accepted for publication in A