A novel and simple test of gait adaptability predicts gold standard measures of functional mobility in stroke surviveors

Background Although there is evidence that stroke survivors have reduced gait adaptability, the underlying mechanisms and the relationship to functional recovery are largely unknown. We explored the relationships between walking adaptability and clinical measures of balance, motor recovery and functional ability in stroke survivors. Methods Stroke survivors (n = 42) stepped to targets, on a 6 m walkway, placed to elicit step lengthening, shortening and narrowing on paretic and non-paretic sides. The number of targets missed during six walks and target stepping speed was recorded. Fugl–Meyer (FM), Berg Balance Scale (BBS), self-selected walking speed (SWWS) and single support (SS) and step length (SL) symmetry (using GaitRite when not walking to targets) were also assessed. Stepwise multiple-linear regression was used to model the relationships between: total targets missed, number missed with paretic and non-paretic legs, target stepping speed, and each clinical measure. Results Regression revealed a significant model for each outcome variable that included only one independent variable. Targets missed by the paretic limb, was a significant predictor of FM (F(1,40) = 6.54, p = 0.014,). Speed of target stepping was a significant predictor of each of BBS (F(1,40) = 26.36, p < 0.0001), SSWS (F(1,40) = 37.00, p < 0.0001). No variables were significant predictors of SL or SS asymmetry. Discussion Speed of target stepping was significantly predictive of BBS and SSWS and paretic targets missed predicted FM, suggesting that fast target stepping requires good balance and accurate stepping demands good paretic leg function. The relationships between these parameters indicate gait adaptability is a clinically meaningful target for measurement and treatment of functionally adaptive walking ability in stroke survivors

Measuring the initial-final mass relation using wide double white dwarf binaries from Gaia DR3

The initial-final mass relation (IFMR) maps the masses of main-sequence stars to their white dwarf descendants. The most common approach to measure the IFMR has been to use white dwarfs in clusters. However, it has been shown that wide double white dwarfs can also be used to measure the IFMR using a Bayesian approach. We have observed a large sample of 90 Gaia double white dwarfs using FORS2 on the VLT. Considering 52 DA + DA, DA + DC, and DC + DC pairs, we applied our extended Bayesian framework to probe the IFMR in exquisite detail. Our monotonic IFMR is well constrained by our observations for initial masses of 1–5 M⊙, with the range of 1–4 M⊙ mostly constrained to a precision of 0.03 M⊙ or better. We add an important extension to the framework, using a Bayesian mixture-model to determine the IFMR robustly in the presence of systems departing from single star evolution. We find a large but uncertain outlier fraction of 59 ± 21 per cent, with outlier systems requiring an additional 0.70_{-0.22}^{+0.40} Gyr uncertainty in their cooling age differences. However, we find that this fraction is dominated by a few systems with massive components near 0.9 M⊙, where we are most sensitive to outliers, but are also able to establish four systems as merger candidates

A DZ white dwarf with a 30 MG magnetic field

Magnetic white dwarfs with field strengths below 10 MG are easy to recognize since the Zeeman splitting of spectral lines appears proportional to the magnetic field strength. For fields ≳100 MG, however, transition wavelengths become chaotic, requiring quantum-chemical predictions of wavelengths and oscillator strengths with a non-perturbative treatment of the magnetic field. While highly accurate calculations have previously been performed for hydrogen and helium, the variational techniques employed become computationally intractable for systems with more than three to four electrons. Modern computational techniques, such as finite-field coupled-cluster theory, allow the calculation of many-electron systems in arbitrarily strong magnetic fields. Because around 25 per cent of white dwarfs have metal lines in their spectra, and some of those are also magnetic, the possibility arises for some metals to be observed in very strong magnetic fields, resulting in unrecognizable spectra. We have identified SDSS J114333.48+661531.83 as a magnetic DZ white dwarf, with a spectrum exhibiting many unusually shaped lines at unknown wavelengths. Using atomic data calculated from computational finite-field coupled-cluster methods, we have identified some of these lines arising from Na, Mg, and Ca. Surprisingly, we find a relatively low field strength of 30 MG, where the large number of overlapping lines from different elements make the spectrum challenging to interpret at a much lower field strength than for DAs and DBs. Finally, we model the field structure of SDSS J1143+6615 finding the data are consistent with an offset dipole

Impact of health warning labels and calorie labels on selection and purchasing of alcoholic and non‐alcoholic drinks: a randomized controlled trial

Aims: To estimate the impact on selection and actual purchasing of (a) health warning labels (text‐only and image‐and‐text) on alcoholic drinks and (b) calorie labels on alcoholic and non‐alcoholic drinks. Design: Parallel‐groups randomised controlled trial. Setting: Drinks were selected in a simulated online supermarket, before being purchased in an actual online supermarket. Participants: Adults in England and Wales who regularly consumed and purchased beer or wine online (n = 651). Six hundred and eight participants completed the study and were included in the primary analysis. Interventions: Participants were randomized to one of six groups in a between‐subjects three [health warning labels (HWLs) (i): image‐and‐text HWL; (ii) text‐only HWL; (iii) no HWL] × 2 (calorie labels: present versus absent) factorial design (n per group 103–113). Measurements: The primary outcome measure was the number of alcohol units selected (with intention to purchase); secondary outcomes included alcohol units purchased and calories selected and purchased. There was no time limit for selection. For purchasing, participants were directed to purchase their drinks immediately (although they were allowed up to 2 weeks to do so). Findings: There was no evidence of main effects for either (a) HWLs or (b) calorie labels on the number of alcohol units selected (HWLs: F(2,599) = 0.406, P = 0.666; calorie labels: F(1,599) = 0.002, P = 0.961). There was also no evidence of an interaction between HWLs and calorie labels, and no evidence of an overall difference on any secondary outcomes. In pre‐specified subgroup analyses comparing the ‘calorie label only’ group (n = 101) with the ‘no label’ group (n = 104) there was no evidence that calorie labels reduced the number of calories selected (unadjusted means: 1913 calories versus 2203, P = 0.643). Among the 75% of participants who went on to purchase drinks, those in the ‘calorie label only’ group (n = 74) purchased fewer calories than those in the ‘no label’ group (n = 79) (unadjusted means: 1532 versus 2090, P = 0.028). Conclusions: There was no evidence that health warning labels reduced the number of alcohol units selected or purchased in an online retail context. There was some evidence suggesting that calorie labels on alcoholic and non‐alcoholic drinks may reduce calories purchased from both types of drinks

The impact of introducing alcohol‐free beer options in bars and public houses on alcohol sales and revenue: a randomised crossover field trial

Aims: The study aimed to estimate the impact of introducing a draught alcohol‐free beer, thereby increasing the relative availability of these products, on alcohol sales and monetary takings in bars and pubs in England. Design: Randomised crossover field trial. Setting: England. Participants: Fourteen venues that did not previously sell draught alcohol‐free beer. Intervention and comparator: Venues completed two intervention periods and two control periods in a randomised order over 8 weeks. Intervention periods involved replacing one draught alcoholic beer with an alcohol‐free beer. Control periods operated business as usual. Measurements: The primary outcome was mean weekly volume (in litres) of draught alcoholic beer sold. The secondary outcome was mean weekly revenue [in GBP (£)] from all drinks. Analyses adjusted for randomised order, special events, season and busyness. Findings: The adjusted mean difference in weekly sales of draught alcoholic beer was −20 L [95% confidence interval (CI) = −41 to +0.4], equivalent to a 4% reduction (95% CI = 8% reduction to 0.1% increase) in the volume of alcoholic draught beer sold when draught alcohol‐free beer was available. Excluding venues that failed at least one fidelity check resulted in an adjusted mean difference of −29 L per week (95% CI = −53 to −5), equivalent to a 5% reduction (95% CI = 8% reduction to 0.8% reduction). The adjusted mean difference in weekly revenue was +61 GBP per week (95% CI = −328 to +450), equivalent to a 1% increase (95% CI = 5% decrease to 7% increase) when draught alcohol‐free beer was available. Conclusions: Introducing a draught alcohol‐free beer in bars and pubs in England reduced the volume of draught alcoholic beer sold by 4% to 5%, with no evidence of the intervention impacting net revenue

Main-sequence companions to white dwarfs – II. The age–activity–rotation relation from a sample of Gaia common proper motion pairs

Magnetic activity and rotation are related to the age of low-mass main-sequence stars. To further constrain these relations, we study a sample of 574 main-sequence stars members of common proper motion pairs with white dwarfs, identified thanks to Gaia astrometry. We use the white dwarfs as age indicators, while the activity indexes and rotational velocities are obtained from the main-sequence companions using standard procedures. We find that stars older than 5 Gyr do not display H αnor Ca II H&K emission unless they are fast rotators due to tidal locking from the presence of unseen companions and that the rotational velocities tend to decrease over time, thus supporting the so-called gyrochronology. However, we also find moderately old stars ( 2–6 Gyr) that are active presumably because they rotate faster than they should for their given ages. This indicates that they may be suffering from weakened magnetic braking or that they possibly evolved through wind accretion processes in the past. The activity fractions that we measure for all stars younger than 5 Gyr range between 10 and 40 per cent. This is line with the expectations, since our sample is composed of F, G, K, and early M stars, which are thought to have short ( log( L H α/ L bol ); log( R HK ) > −5) typically found in inactive M stars or weakly active/inactive F, G, K stars

Gaia white dwarfs within 40 pc I : spectroscopic observations of new candidates

We present a spectroscopic survey of 230 white dwarf candidates within 40 pc of the Sun from the William Herschel Telescope and Gran Telescopio Canarias. All candidates were selected from Gaia Data Release 2 (DR2) and in almost all cases had no prior spectroscopic classifications. We find a total of 191 confirmed white dwarfs and 39 main-sequence star contaminants. The majority of stellar remnants in the sample are relatively cool (〈Teff〉 = 6200 K), showing either hydrogen Balmer lines or a featureless spectrum, corresponding to 89 DA and 76 DC white dwarfs, respectively. We also recover two DBA white dwarfs and 9–10 magnetic remnants. We find two carbon-bearing DQ stars and 14 new metal-rich white dwarfs. This includes the possible detection of the first ultra-cool white dwarf with metal lines. We describe three DZ stars for which we find at least four different metal species, including one which is strongly Fe- and Ni-rich, indicative of the accretion of a planetesimal with core-Earth composition. We find one extremely massive (1.31 ± 0.01 M⊙) DA white dwarf showing weak Balmer lines, possibly indicating stellar magnetism. Another white dwarf shows strong Balmer line emission but no infrared excess, suggesting a low-mass sub-stellar companion. High spectroscopic completeness (>99%) has now been reached for Gaia DR2 sources within 40 pc sample, in the northern hemisphere (δ > 0 deg) and located on the white dwarf cooling track in the Hertzsprung-Russell diagram. A statistical study of the full northern sample is presented in a companion paper

Gaia white dwarfs within 40 pc – III. Spectroscopic observations of new candidates in the Southern hemisphere

We present a spectroscopic survey of 248 white dwarf candidates within 40 pc of the Sun; of these 244 are in the Southern hemisphere. Observations were performed mostly with the Very Large Telescope (X-Shooter) and Southern Astrophysical Research Telescope. Almost all candidates were selected from Gaia Data Release 3 (DR3). We find a total of 246 confirmed white dwarfs, 209 of which had no previously published spectra, and two main-sequence star contaminants. Of these, 100 white dwarfs display hydrogen Balmer lines, 69 have featureless spectra, and two show only neutral helium lines. Additionally, 14 white dwarfs display traces of carbon, while 37 have traces of other elements that are heavier than helium. We observe 35 magnetic white dwarfs through the detection of Zeeman splitting of their hydrogen Balmer or metal spectral lines. High spectroscopic completeness (> 97 per cent) has now been reached, such that we have 1058 confirmed Gaia DR3 white dwarfs out of 1083 candidates within 40 pc of the Sun at all declinations

Visuomotor control strategies for precision stepping in man

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