The Hyper Suprime-Cam SSP survey: Overview and survey design

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey

Video game studies using a natural experiment

We utilize a natural experiment in Japan and study how video games affect people

Causal effect of video game play on mental well-being: a quasi-experimental study among Japanese population

Findings from previous observational and experimental studies on the relationship between video gaming and mental well-being have been inconsistent, warranting further investigation of their causal relationship outside a laboratory setting. Through the unique use of game console lotteries as a quasi-experiment, we identified the causal relationship between video gaming and well-being. We employed multiple causal inference methods, including multivariate regression, propensity score matching, and instrumental variable method, to estimate the average causal effect. Further, we utilized machine learning to evaluate the individual causal effects. Multiple-round online surveys of game players and non-players collected data from 97,602 Japanese participants aged 10-69 between 2020 and 2022. Exposures included ownership of popular game consoles (Nintendo Switch and PlayStation5) and gameplay time. We found that owning a Nintendo Switch or PlayStation5 and gameplay time improved mental health and life satisfaction, assessed by the Kessler Psychological Distress Scale (K6) and the Satisfaction with Life Scale (SWLS). Specifically, Nintendo Switch ownership reduced psychological distress by 0.60 standard deviations (SD), while PlayStation5 ownership decreased it by 0.12 SD. Similarly, PlayStation5 ownership improved life satisfaction by 0.23 SD. Further, an additional gaming hour reduced psychological distress by 0.20 SD and improved life satisfaction by 0.26 SD, though gaming beyond three hours daily lessened the psychological benefits. Machine learning revealed divergent impacts between consoles, with PlayStation5 showing lower benefits for females and adolescents, while no such pattern emerged for Nintendo Switch. These findings underscore moderate video gaming’s benefits for digital well-being and call for additional investigation into underlying mechanisms

Magnetic Moment of the Isomeric State of 75^{75}Cu Measured with a Highly Spin-aligned Beam

International audienceThe magnetic moment of the isomeric state of the neutron-rich ^75Cu nucleus was measured using a highly spin-aligned beam produced via a two-step reaction scheme. In the experiment carried out at the BigRIPS at RIBF, we achieved to produce spin alignment reaching 30% by employing the one-proton removal from ^76Zn to produce ^75Cu. In the magnetic moment measurement, a method of time-differential perturbed angular distribution (TDPAD) was employed. Precession of the isomeric state with spin parity of 3/2^− was clearly observed with significance larger than 5σ in the TDPAD spectrum. The magnetic moment of the isomeric state of ^75Cu was determined to be μ = 1.40(6)μ_N

Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program

International audienceThis paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg|$^2$| in all five broad-band filters (⁠|$grizy$|⁠) to the nominal survey exposure (10 min in |$gr$| and 20 min in |$izy$|⁠). Partially observed areas are also included in the release; about 1100 deg|$^2$| is observed in at least one filter and one exposure. The median seeing in the i-band is |${0_{.}^{\prime \prime }6}$|⁠, demonstrating the superb image quality of the survey. The Deep (26 deg|$^2$|⁠) and UltraDeep (4 deg|$^2$|⁠) data are jointly processed and the UltraDeep-COSMOS field reaches an unprecedented depth of |$i\sim 28$| at |$5 \, \sigma$| for point sources. In addition to the broad-band data, narrow-band data are also available in the Deep and UltraDeep fields. This release includes a major update to the processing pipeline, including improved sky subtraction, PSF modeling, object detection, and artifact rejection. The overall data quality has been improved, but this release is not without problems; there is a persistent deblender problem as well as new issues with masks around bright stars. The user is encouraged to review the issue list before utilizing the data for scientific explorations. All the image products as well as catalog products are available for download. The catalogs are also loaded into a database, which provides an easy interface for users to retrieve data for objects of interest. In addition to these main data products, detailed galaxy shape measurements withheld from Public Data Release 1 (PDR1) are now available to the community. The shape catalog is drawn from the S16A internal release, which has a larger area than PDR1 (160 deg|$^2$|⁠). All products are available at the data release site, https://hsc-release.mtk.nao.ac.jp/

Third data release of the Hyper Suprime-Cam Subaru Strategic Program

This paper presents the third data release of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), a wide-field multi-band imaging survey with the Subaru 8.2 m telescope. HSC-SSP has three survey layers (Wide, Deep, and UltraDeep) with different area coverages and depths, designed to address a wide array of astrophysical questions. This third release from HSC-SSP includes data from 278 nights of observing time and covers about 670 deg2 in all five broad-band filters (grizy) at the full depth (∼26 mag at 5σ depending on filter) in the Wide layer. If we include partially observed areas, the release covers 1470 deg2. The Deep and UltraDeep layers have ∼ 80% of the originally planned integration times, and are considered done, as we have slightly changed the observing strategy in order to compensate for various time losses. There are a number of updates in the image processing pipeline. Of particular importance is the change in the sky subtraction algorithm; we subtract the sky on small scales before the detection and measurement stages, which has significantly reduced the number of false detections. Thanks to this and other updates, the overall quality of the processed data has improved since the previous release. However, there are limitations in the data (for example, the pipeline is not optimized for crowded fields), and we encourage the user to check the quality assurance plots as well as a list of known issues before exploiting the data

The Hyper Suprime-Cam SSP survey: Overview and survey design

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey

National trends in the outcomes of subarachnoid haemorrhage and the prognostic influence of stroke centre capability in Japan: retrospective cohort study

Objectives To examine the national, 6-year trends in in-hospital clinical outcomes of patients with subarachnoid haemorrhage (SAH) who underwent clipping or coiling and the prognostic influence of temporal trends in the Comprehensive Stroke Center (CSC) capabilities on patient outcomes in Japan.Design Retrospective study.Setting Six hundred and thirty-one primary care institutions in Japan.Participants Forty-five thousand and eleven patients with SAH who were urgently hospitalised, identified using the J-ASPECT Diagnosis Procedure Combination database.Primary and secondary outcome measures Annual number of patients with SAH who remained untreated, or who received clipping or coiling, in-hospital mortality and poor functional outcomes (modified Rankin Scale: 3–6) at discharge. Each CSC was assessed using a validated scoring system (CSC score: 1–25 points).Results In the overall cohort, in-hospital mortality decreased (year for trend, OR (95% CI): 0.97 (0.96 to 0.99)), while the proportion of poor functional outcomes remained unchanged (1.00 (0.98 to 1.02)). The proportion of patients who underwent clipping gradually decreased from 46.6% to 38.5%, while that of those who received coiling and those left untreated gradually increased from 16.9% to 22.6% and 35.4% to 38%, respectively. In-hospital mortality of coiled (0.94 (0.89 to 0.98)) and untreated (0.93 (0.90 to 0.96)) patients decreased, whereas that of clipped patients remained stable. CSC score improvement was associated with increased use of coiling (per 1-point increase, 1.14 (1.08 to 1.20)) but not with short-term patient outcomes regardless of treatment modality.Conclusions The 6-year trends indicated lower in-hospital mortality for patients with SAH (attributable to better outcomes), increased use of coiling and multidisciplinary care for untreated patients. Further increasing CSC capabilities may improve overall outcomes, mainly by increasing the use of coiling. Additional studies are necessary to determine the effect of confounders such as aneurysm complexity on outcomes of clipped patients in the modern endovascular era