224 research outputs found

    Social network engagement and subjective well-being: a life-course perspective

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    Social networking is a digital phenomenon embraced by billions worldwide. Use of online social platforms has the potential to generate a number of benefits including to well-being from enhanced social connectedness and social capital accumulation, but is also associated with several negative behaviours and impacts. Employing a life-course perspective, this paper explores social networking use and its relationship with measures of subjective well-being. Large-scale UK panel data from wave 3 (2011-12) and 6 (2014-15) of Understanding Society reveals that social network users are on average younger, aged under 25, but that rising use is reported across the life-course including into old age. Probit, multinomial logistic, and ANCOVA and change-score estimations reveal that membership, and greater use, of social networks is associated with higher levels of overall life satisfaction. However, heavy use of social networking sites has negative impacts, reflected in reductions in subjective well-being. Socio-economic disadvantage may drive these impacts among young (in education), unemployed and economically inactive heavy SNS users

    Home-based Reach-to-Grasp training for people after stroke is feasible: A pilot randomised controlled trial

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    © The Author(s) 2016. Objective: To determine feasibility of a randomised controlled trial (RCT) of home-based Reach-to-Grasp training after stroke. Design: single-blind parallel group RCT. Participants: Residual arm deficit less than 12 months post-stroke. Interventions: Reach-to-Grasp training in 14 one-hour therapist's visits over 6 weeks, plus one hour self-practice per day (total 56 hours). Control: Usual care. Main Measures: Action Research Arm Test (ARAT), Wolf Motor Function Test (WMFT), pre-randomisation, 7, 12, 24 weeks post-randomisation. Results: Forty-seven participants (Reach-to-Grasp=24, usual care=23) were randomised over 17 months. Reach-to-Grasp participants received a median (IQR) 14 (13,14) visits, and performed 157 (96,211) repetitions per visit; plus 30 minutes (22,45) self-practice per day. Usual care participants received 10.5 (5,14) therapist visits, comprising 38.6 (30,45) minutes of arm therapy with 16 (6,24) repetitions of functional tasks per visit. Median ARAT scores in the reach-to-grasp group were 8.5 (3.0,24.0) at baseline and 14.5 (3.5,26.0) at 24 weeks compared to median of 4 at both time points (IQR: baseline (3.0,14.0), 24 weeks (3.0,30.0)) in the usual-care group. Median WMFT tasks completed at baseline and 24 weeks were 6 (3.0,11.5) and 8.5 (4.5,13.5) respectively in the reach-to-grasp group and 4 (3.0,10.0), 6 (3.0,14.0) in the usual care group. Incidence of arm pain was similar between groups. The study was stopped before 11 patients reached the 24 weeks assessment. Conclusions: An RCT of home-based Reach-to-Grasp training after stroke is feasible and safe. With ARAT being our preferred measure it is estimated that 240 participants will be needed for a future two armed trial

    Ab-initio Quantum Enhanced Optical Phase Estimation Using Real-time Feedback Control

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    Optical phase estimation is a vital measurement primitive that is used to perform accurate measurements of various physical quantities like length, velocity and displacements. The precision of such measurements can be largely enhanced by the use of entangled or squeezed states of light as demonstrated in a variety of different optical systems. Most of these accounts however deal with the measurement of a very small shift of an already known phase, which is in stark contrast to ab-initio phase estimation where the initial phase is unknown. Here we report on the realization of a quantum enhanced and fully deterministic phase estimation protocol based on real-time feedback control. Using robust squeezed states of light combined with a real-time Bayesian estimation feedback algorithm, we demonstrate deterministic phase estimation with a precision beyond the quantum shot noise limit. The demonstrated protocol opens up new opportunities for quantum microscopy, quantum metrology and quantum information processing.Comment: 5 figure

    Dissecting mitosis by RNAi in Drosophila tissue culture cells

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    Here we describe a detailed methodology to study the function of genes whose products function during mitosis by dsRNA-mediated interference (RNAi) in cultured cells of Drosophila melanogaster. This procedure is particularly useful for the analysis of genes for which genetic mutations are not available or for the dissection of complicated phenotypes derived from the analysis of such mutants. With the advent of whole genome sequencing it is expected that RNAi-based screenings will be one method of choice for the identification and study of novel genes involved in particular cellular processes. In this paper we focused particularly on the procedures for the proper phenotypic analysis of cells after RNAi-mediated depletion of proteins required for mitosis, the process by which the genetic information is segregated equally between daughter cells. We use RNAi of the microtubule-associated protein MAST/Orbit as an example for the usefulness of the technique

    NGTS-13b: A hot 4.8 Jupiter-mass planet transiting a subgiant star

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    We report the discovery of the massive hot Jupiter NGTS-13b by the Next Generation Transit Survey (NGTS). The V = 12.7 host star is likely in the subgiant evolutionary phase with log g_{*} = 4.04 ±\pm 0.05, Teff_{eff} = 5819 ±\pm 73 K, M_{*} = 1.300.18+0.11^{+0.11}_{-0.18} M_{\odot}, and R_{*} = 1.79 ±\pm 0.06 R_{\odot}. NGTS detected a transiting planet with a period of P = 4.12 days around the star, which was later validated with the Transiting Exoplanet Survey Satellite (TESS; TIC 454069765). We confirm the planet using radial velocities from the CORALIE spectrograph. Using NGTS and TESS full-frame image photometry combined with CORALIE radial velocities we determine NGTS-13b to have a radius of RP_{P} = 1.142 ±\pm 0.046 RJup_{Jup}, mass of MP_{P} = 4.84 ±\pm 0.44 MJup_{Jup} and eccentricity e = 0.086 ±\pm 0.034. Some previous studies suggest that \sim4 MJup_{Jup} may be a border between two separate formation scenarios (e.g., core accretion and disk instability) and that massive giant planets share similar formation mechanisms as lower-mass brown dwarfs. NGTS-13b is just above 4 MJup_{Jup} making it an important addition to the statistical sample needed to understand the differences between various classes of substellar companions. The high metallicity, [Fe/H] = 0.25 ±\pm 0.17, of NGTS-13 does not support previous suggestions that massive giants are found preferentially around lower metallicity host stars, but NGTS-13b does support findings that more massive and evolved hosts may have a higher occurrence of close-in massive planets than lower-mass unevolved stars

    NGTS-5b: A highly inflated planet offering insights into the sub-Jovian desert

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    Context: Planetary population analysis gives us insight into formation and evolution processes. For short-period planets, the subJovian desert has been discussed in recent years with regard to the planet population in the mass/period and radius/period parameter space without taking stellar parameters into account. The Next Generation Transit Survey (NGTS) is optimised for detecting planets in this regime, which allows for further analysis of the sub-Jovian desert. Aims: With high-precision photometric surveys (e.g. with NGTS and TESS), which aim to detect short period planets especially around M/K-type host stars, stellar parameters need to be accounted for when empirical data are compared to model predictions. Presenting a newly discovered planet at the boundary of the sub-Jovian desert, we analyse its bulk properties and use it to show the properties of exoplanets that border the sub-Jovian desert. Methods: Using NGTS light curve and spectroscopic follow-up observations, we confirm the planetary nature of planet NGTS-5b and determine its mass. Using exoplanet archives, we set the planet in context with other discoveries. Results: NGTS-5b is a short-period planet with an orbital period of 3.3569866 +- 0.0000026 days. With a mass of 0.229 +- 0.037 MJup and a radius of 1.136 +- 0.023 RJup, it is highly inflated. Its mass places it at the upper boundary of the sub-Jovian desert. Because the host is a K2 dwarf, we need to account for the stellar parameters when NGTS-5b is analysed with regard to planet populations. Conclusions: With red-sensitive surveys (e.g. with NGTS and TESS), we expect many more planets around late-type stars to be detected. An empirical analysis of the sub-Jovian desert should therefore take stellar parameters into account

    NGTS discovery of a highly inflated Saturn-mass planet and a highly irradiated hot Jupiter: NGTS-26 b and NGTS-27 b

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    We report the discovery of two new transiting giant exoplanets NGTS-26 b and NGTS-27 b by the Next Generation Transit Survey (NGTS). NGTS-26 b orbits around a G6-type main sequence star every 4.52 days. It has a mass of 0.29-0.06+0.07 MJup and a radius of 1.33-0.05+0.06 RJup making it a Saturn-mass planet with a highly inflated radius. NGTS-27 b orbits around a slightly evolved G3-type star every 3.37 days. It has a mass of 0.59-0.07+0.10 MJup and a radius of 1.40±0.04 RJup, making it a relatively standard hot Jupiter. The transits of these two planetary systems were re-observed and confirmed in photometry by the SAAO 1.0-m telescope, 1.2-m Euler Swiss telescope as well as the TESS spacecraft, and their masses were derived spectroscopically by the CORALIE, FEROS and HARPS spectrographs. Both giant exoplanets are highly irradiated by their host stars and present an anomalously inflated radius, especially NGTS-26 b which is one of the largest objects among peers of similar mass

    NGTS-11 b (TOI-1847 b): A Transiting Warm Saturn Recovered from a TESS Single-transit Event

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    We report the discovery of NGTS-11 b (=TOI-1847 b), a transiting Saturn in a 35.46-day orbit around a mid K-type star (Teff=5050 K). We initially identified the system from a single-transit event in a TESS full-frame image light-curve. Following seventy-nine nights of photometric monitoring with an NGTS telescope, we observed a second full transit of NGTS-11 b approximately one year after the TESS single-transit event. The NGTS transit confirmed the parameters of the transit signal and restricted the orbital period to a set of 13 discrete periods. We combined our transit detections with precise radial velocity measurements to determine the true orbital period and measure the mass of the planet. We find NGTS-11 b has a radius of 0.817+0.028-0.032 RJR_J, a mass of 0.344+0.092-0.073 MJM_J, and an equilibrium temperature of just 435+34-32 K, making it one of the coolest known transiting gas giants. NGTS-11 b is the first exoplanet to be discovered after being initially identified as a TESS single-transit event, and its discovery highlights the power of intense photometric monitoring in recovering longer-period transiting exoplanets from single-transit events

    The Next Generation Transit Survey (NGTS)

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    © 2017 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. We describe the Next Generation Transit Survey (NGTS), which is a ground-based project searching for transiting exoplanets orbiting bright stars. NGTS builds on the legacy of previous surveys, most notably WASP, and is designed to achieve higher photometric precision and hence find smaller planets than have previously been detected from the ground. It also operates in red light,maximizing sensitivity to late K and earlyMdwarf stars. The survey specifications call for photometric precision of 0.1 per cent in red light over an instantaneous field of view of 100 deg 2 , enabling the detection of Neptune-sized exoplanets around Sun-like stars and super-Earths around M dwarfs. The survey is carried out with a purpose-built facility at Cerro Paranal, Chile, which is the premier site of the European Southern Observatory (ESO). An array of twelve 20 cm f/2.8 telescopes fitted with back-illuminated deep-depletion CCD cameras is used to survey fields intensively at intermediateGalactic latitudes. The instrument is also ideally suited to ground-based photometric follow-up of exoplanet candidates from space telescopes such as TESS, Gaia and PLATO. We present observations that combine precise autoguiding and the superb observing conditions at Paranal to provide routine photometric precision of 0.1 per cent in 1 h for stars with I-band magnitudes brighter than 13. We describe the instrument and data analysis methods as well as the status of the survey, which achieved first light in 2015 and began full-survey operations in 2016. NGTS data will be made publicly available through the ESO archive
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