Aims. In archival 2.2 m MPG-ESO/WFI data we discovered several mass peaks through weak gravitational lensing, forming a possible supercluster at redshift 0.45. Through wide-field imaging and ...spectroscopy we aim to identify the supercluster centre, confirm individual member clusters, and detect possible connecting filaments. Methods. Through multi-colour imaging with CFHT/Megaprime and INT/WFC we identify a population of early-type galaxies and use it to trace the supercluster network. EMMI/NTT multi-object spectroscopy is used to verify the initial shear-selected cluster candidates. We use weak gravitational lensing to obtain mass estimates for the supercluster centre and the filaments. Results. We identified the centre of the SCL2243-0935 supercluster, MACS J2243-0935, which was found independently by Ebeling et al. (2001, 2010). We found 13 more clusters or overdensities embedded in a large filamentary network. Spectroscopic confirmation for about half of them is still pending. Three \hbox{$(5{-}15)\,h_{70}^{-1}$}(5−15) h70-1 Mpc filaments are detected, and we estimate the global size of SCL2243 to be \hbox{$45\times15\times50\,h_{70}^{-1}$}45×15×50 h70-1 Mpc, making it one of the largest superclusters known at intermediate redshifts. Weak lensing yields \hbox{$r_{200}=(2.06\pm0.13)\,h_{70}^{-1}$}r200=(2.06±0.13) h70-1 Mpc and M200 = (1.54 ± 0.29) × 1015 M⊙ for MACS J2243 with M/L = 428 ± 82, very similar to results from size-richness cluster scaling relations. Integrating the weak lensing surface mass density over the supercluster network (defined by increased i-band luminosity or g − i colours), we find (1.53 ± 1.01) × 1015 M⊙ and M/L = 305 ± 201 for the three main filaments, consistant with theoretical predictions. The filaments’ projected dimensionless surface mass density κ varies between 0.007 − 0.012, corresponding to ρ/ρcrit = 10 − 100 depending on location and de-projection. The greatly varying density of the cosmic web is also reflected in the mean colour of galaxies, e.g. ⟨ g − i ⟩ = 2.27 mag for the supercluster centre and 1.80 mag for the filaments. Conclusions. SCL2243 is significantly larger and much more richly structured than other known superclusters such as A901/902 or MS0302 studied with weak lensing before. It is a text-book supercluster with little contamination along the line of sight, making it a perfect sandbox for testing new techniques probing the cosmic web.
Cosmic shear, that is weak gravitational lensing by the large-scale matter structure of the Universe, is a primary cosmological probe for several present and upcoming surveys investigating dark ...matter and dark energy, such as Euclid or WFIRST. The probe requires an extremely accurate measurement of the shapes of millions of galaxies based on imaging data. Crucially, the shear measurement must address and compensate for a range of interwoven nuisance effects related to the instrument optics and detector, noise in the images, unknown galaxy morphologies, colors, blending of sources, and selection effects. This paper explores the use of supervised machine learning as a tool to solve this inverse problem. We present a simple architecture that learns to regress shear point estimates and weights via shallow artificial neural networks. The networks are trained on simulations of the forward observing process, and take combinations of moments of the galaxy images as inputs. A challenging peculiarity of the shear measurement task, in terms of machine learning applications, is the combination of the noisiness of the input features and the requirements on the statistical accuracy of the inverse regression. To address this issue, the proposed training algorithm minimizes bias over multiple realizations of individual source galaxies, reducing the sensitivity to properties of the overall sample of source galaxies. Importantly, an observational selection function of these source galaxies can be straightforwardly taken into account via the weights. We first introduce key aspects of our approach using toy-model simulations, and then demonstrate its potential on images mimicking Euclid data. Finally, we analyze images from the GREAT3 challenge, obtaining competitively low multiplicative and additive shear biases despite the use of a simple training set. We conclude that the further development of suited machine learning approaches is of high interest to meet the stringent requirements on the shear measurement in current and future surveys. We make a demonstration implementation of our technique publicly available.
We present a bright galaxy sample with accurate and precise photometric redshifts (photo-zs), selected using ugriZYJHKs photometry from the Kilo-Degree Survey (KiDS) Data Release 4. The highly pure ...and complete dataset is flux-limited at r < 20 mag, covers ∼1000 deg2, and contains about 1 million galaxies after artifact masking. We exploit the overlap with Galaxy And Mass Assembly spectroscopy as calibration to determine photo-zs with the supervised machine learning neural network algorithm implemented in the ANNz2 software. The photo-zs have a mean error of |⟨δz⟩|∼5 × 10−4 and low scatter (scaled mean absolute deviation of ∼0.018(1 + z)); they are both practically independent of the r-band magnitude and photo-z at 0.05 < zphot < 0.5. Combined with the 9-band photometry, these allow us to estimate robust absolute magnitudes and stellar masses for the full sample. As a demonstration of the usefulness of these data, we split the dataset into red and blue galaxies, used them as lenses, and measured the weak gravitational lensing signal around them for five stellar mass bins. We fit a halo model to these high-precision measurements to constrain the stellar-mass–halo-mass relations for blue and red galaxies. We find that for high stellar mass (M⋆ > 5 × 1011 M⊙), the red galaxies occupy dark matter halos that are much more massive than those occupied by blue galaxies with the same stellar mass.
The prevalence of overweight and elevated cardiovascular disease (CVD) risk among workers in the construction industry is relatively high. Improving lifestyle lowers CVD risk and may have ...work-related benefits. The purpose of the study was to evaluate the effects on physical activity (PA), diet, and smoking of a lifestyle intervention consisting of individual counseling among male workers in the construction industry with an elevated risk of cardiovascular disease (CVD).
In a randomized controlled trial including 816 male blue- and white-collar workers in the construction industry with an elevated risk of CVD, usual care was compared to a 6-month lifestyle intervention. The intervention consisted of individual counseling using motivational interviewing techniques, and was delivered by an occupational physician or occupational nurse. In three face to face and four telephone contacts, the participant's risk profile, personal determinants, and barriers for behavior change were discussed, and personal goals were set. Participants chose to aim at either diet and PA, or smoking. Data were collected at baseline and after six and 12 months, by means of a questionnaire. To analyse the data, linear and logistic regression analyses were performed.
The intervention had a statistically significant beneficial effect on snack intake (β-1.9, 95%CI -3.7; -0.02) and fruit intake (β 1.7, 95%CI 0.6; 2.9) at 6 months. The effect on snack intake was sustained until 12 months; 6 months after the intervention had ended (β -1.9, 95%CI -3.6; -0.2). The intervention effects on leisure time PA and metabolic equivalent-minutes were not statistically significant. The beneficial effect on smoking was statistically significant at 6 (OR smoking 0.3, 95%CI 0.1;0.7), but not at 12 months (OR 0.8, 95%CI 0.4; 1.6).
Beneficial effects on smoking, fruit, and snack intake can be achieved by an individual-based lifestyle intervention among male construction workers with an elevated risk of CVD. Future research should be done on strategies to improve leisure time PA and on determinants of maintenance of changed behavior. Considering the rising prevalence of unhealthy lifestyle and CVD, especially in the aging population, implementation of this intervention in the occupational health care setting is recommended.
Current Controlled Trials ISRCTN60545588
Abstract Objective To study the association between commuter cycling and all-cause sickness absence, and the possible dose–response relationship between absenteeism and the distance, frequency and ...speed of commuter cycling. Method Cross-sectional data about cycling in 1236 Dutch employees were collected using a self-report questionnaire. Company absenteeism records were checked over a one-year period (May 2007–April 2008). Propensity scores were used to make groups comparable and to adjust for confounders. Zero-inflated Poisson models were used to assess differences in absenteeism between cyclists and non-cyclists. Results The mean total duration of absenteeism over the study year was more than 1 day shorter in cyclists than in non-cyclists. This can be explained by the higher proportion of people with no absenteeism in the cycling group. A dose–response relationship was observed between the speed and distance of cycling and absenteeism. Compared to people who cycle a short distance (≤ 5 km) three times a week, people who cycle more often and longer distances are absent for fewer days on average. Conclusion Cycling to work is associated with less sickness absence. The more often people cycle to work and the longer the distance travelled, the less they report sick.
In recent years, many tailored lifestyle counseling programs have become available through the Internet. Previous research into such programs has shown selective enrollment of relatively healthy ...people. However, because of the known dose-response relationship between the intensity and frequency of counseling and the behavior change outcomes, selective retention may also be a concern.
The aim of this study was to identify rates and determinants of repeat participation in a Web-based health behavior change program.
A Web-based health behavior change program aimed to increase people's awareness of their own lifestyle, to promote physical activity, and to prevent overweight and obesity was available on the Internet from July 2004 onward at no cost. Univariate and multivariate logistic regression analyses were conducted to identify characteristics of people who participated in the program more than once. Age, compliance with physical activity guidelines, body mass index, smoking status, and the consumption of fruit, vegetables, and alcohol were included in the analyses.
A total of 9774 people participated in the baseline test, of which 940 used the site more than once (9.6%). After exclusion of individuals with incomplete data, 6272 persons were included in the analyses. Of these 6272 people, 5560 completed only the baseline test and 712 also participated in follow-up. Logistic regression predicting repeated use determined that older individuals were more likely to participate in follow-up than people aged 15-20 years. The odds ratios for the age categories 41-50, 51-60, and > 60 years were 1.40 (95% CI = 1.02-1.91), 1.43 (95% CI = 1.02-2.01), and 1.68 (95% CI = 1.03-2.72), respectively. Individuals who never smoked were more likely to participate repeatedly than current smokers and ex-smokers (OR = 1.44, 95% CI = 1.14-1.82 and OR = 1.49, 95% CI = 1.17-1.89, respectively). People meeting the guidelines for physical activity of moderate intensity (OR = 1.23 95% CI = 1.04-1.46) and for vegetable consumption (OR = 1.26 95% CI = 1.01-1.57) were also more likely to participate repeatedly than people who did not, as were obese people compared to individuals with normal weight (OR = 1.41 95% CI = 1.09-1.82).
For some variables, this study confirms our concern that behavioral intervention programs may reach those who need them the least. However, contrary to most expectations, we found that obese people were more likely to participate in follow-up than people of normal body weight. The non-stigmatizing way of addressing body weight through the Internet may be part of the explanation for this. Our findings suggest that Web-based health behavior change programs may be more successful in the area of weight management than in many other health-related areas. They also stress the importance of adequate coverage of weight management in Web-based health promotion programs, as a driver to continue participation for overweight and obese people.
► Neglect patients often show an ipsilesional shift of their subjective auditory midline. ► Leftsided optokinetic stimulation (OKS) transiently normalized this auditory midline shift in leftsided ...neglect, and led to a significant positive after-effect 30min post-stimulation. ► Repetitive leftward OKS (20 treatment sessions) led to a significant and enduring reduction of both visual and auditory neglect phenomena while visual scanning therapy had no effect on auditory and only small effects on visual neglect. ► In conclusion, OKS induces significant recovery from auditory and visual neglect.
Optokinetic stimulation (OKS) modulates many facets of the neglect syndrome. This sensory stimulation technique is known to activate multiple brain regions (temporo-parietal cortex, basal ganglia, brain stem, cerebellum) some of which are involved in auditory and visual space coding. Here, we evaluated whether OKS modulates auditory neglect transiently and induces a sustained effect (Study 1), and whether repetitive OKS permanently recovers auditory neglect (Study 2). In Study 1, 20 patients with visuospatial neglect and auditory neglect in an auditory midline task following rightsided stroke were randomly allocated to an experimental and a control group matched for neglect severity and socio-demographic factors. Both groups showed a stable, pathological shift of their auditory subjective median plane (ASMP) in front space to the right side. During leftward OKS the experimental group showed a complete normalization of the shift of the ASMP, which endured until 30min poststimulation, and returned almost to baseline values 24h after OKS. In contrast, the control group who viewed the identical but static dot pattern, showed neither change in their ASMP during this condition, nor any significant change at 30min or 24h poststimulation. In Study 2, we show in two samples of neglect patients (N=3 each) that repetitive leftward OKS with smooth pursuit eye movements as a therapy induces lasting improvements in auditory (the ASMP) and visual neglect while visual scanning therapy yielded no measurable effects on auditory and significantly smaller effects on visual neglect. In conclusion, the experiments show that a single session of OKS induces rapid though transient recovery from auditory neglect including a sustained effect after termination of stimulation, while repetitive OKS therapy yields enduring and multimodal recovery from auditory and visual neglect. OKS therapy with pursuit eye movements therefore represents a multimodally effective and easily applicable technique for the treatment of auditory and visual neglect.
Abstract
We present a weak gravitational lensing analysis of 815 deg2 of i-band imaging from the Kilo-Degree Survey (KiDS-i-800). In contrast to the deep r-band observations, which take priority ...during excellent seeing conditions and form the primary KiDS data set (KiDS‐r‐450), the complementary yet shallower KiDS-i-800 spans a wide range of observing conditions. The overlapping KiDS-i-800 and KiDS‐r‐450 imaging therefore provides a unique opportunity to assess the robustness of weak lensing measurements. In our analysis we introduce two new ‘null’ tests. The ‘nulled’ two-point shear correlation function uses a matched catalogue to show that the calibrated KiDS-i-800 and KiDS‐r‐450 shear measurements agree at the level of 1 ± 4 per cent. We use five galaxy lens samples to determine a ‘nulled’ galaxy–galaxy lensing signal from the full KiDS-i-800 and KiDS‐r‐450 surveys and find that the measurements agree to 7 ± 5 per cent when the KiDS-i-800 source redshift distribution is calibrated using either spectroscopic redshifts, or the 30-band photometric redshifts from the COSMOS survey.
Background and purpose
Endovascular therapy (ET) is superior to intravenous thrombolysis (IVT) in selected patients with anterior circulation large vessel occlusions. However, it is unclear if this ...positive effect also applies to patients with extensive early ischaemic changes. The aim of this study was to analyze the impact of the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on the CT angiography source images (SI) on outcome after ET or IVT.
Methods
Using our prospectively obtained stroke database and the admission SI‐ASPECTS divided into three groups (0–5, 6–7 and 8–10), primarily the rates of good outcome modified Rankin Scale (mRS) ≤2 at discharge after either ET (n = 255) or IVT (n = 479) were compared.
Results
A favorable SI‐ASPECTS (8–10) was present in 501 patients, 132 patients had a moderately favorable SI‐ASPECTS (6–7) and 101 patients had an unfavorable SI‐ASPECTS (0–5). Irrespective of the treatment modality, no patient with an unfavorable SI‐ASPECTS had a good outcome and 38% died during hospital stay. Whilst significantly more patients with a favorable SI‐ASPECTS had a good outcome after ET than after IVT (51% vs. 35%, P < 0.01), there was only a non‐significant trend towards a good outcome after ET than after IVT in patients with a moderately favorable ASPECTS (25% vs. 14%, P = 0.1).
Conclusion
Patients with extensive early ischaemic changes on CT scans (SI‐ ASPECTS ≤5) might not profit from ET. The impact of ET on outcome in patients with moderately favorable SI‐ASPECTS should be addressed in further trials.
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Abstract
Accurate photometric calibration of optical data is crucial for photometric redshift estimation. We present the Softassign Procrustes Matching (SPM) method to improve the colour calibration ...upon the commonly used Stellar Locus Regression (SLR) method for the COMBO-17 survey. Our colour calibration approach can be categorised as a point-set matching method, which is frequently used in medical imaging and pattern recognition. We attain a photometric redshift precision Δz/(1 + z
s) of better than 2 per cent. Our method is based on aligning the stellar locus of the uncalibrated stars to that of a spectroscopic sample of the Sloan Digital Sky Survey standard stars. We achieve our goal by finding a correspondence matrix between the two point-sets and applying the matrix to estimate the appropriate translations in multidimensional colour space. The SPM method is able to find the translation between two point-sets, despite the existence of noise and incompleteness of the common structures in the sets, as long as there is a distinct structure in at least one of the colour–colour pairs. We demonstrate the precision of our colour calibration method with a mock catalogue. The SPM colour calibration code is publicly available at https://neuronphysics@bitbucket.org/neuronphysics/spm.git.
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