| 1. |
- Schellart, P., et al.
(författare)
-
Detecting cosmic rays with the LOFAR radio telescope
- 2013
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 560, s. 1-14
-
Tidskriftsartikel (refereegranskat)abstract
- The low frequency array (LOFAR), is the first radio telescope designed with the capability to measure radio emission from cosmic-ray induced air showers in parallel with interferometric observations. In the first ~2 years of observing, 405 cosmic-ray events in the energy range of 1016−1018 eV have been detected in the band from 30−80 MHz. Each of these air showers is registered with up to ~1000 independent antennas resulting in measurements of the radio emission with unprecedented detail. This article describes the dataset, as well as the analysis pipeline, and serves as a reference for future papers based on these data. All steps necessary to achieve a full reconstruction of the electric field at every antenna position are explained, including removal of radio frequency interference, correcting for the antenna response and identification of the pulsed signal.
|
|
| 2. |
- Corstanje, A., et al.
(författare)
-
LOFAR : Detecting Cosmic Rays with a Radio Telescope
- 2011
-
Ingår i: Proceedings of the 32nd International Cosmic Ray Conference. - : International Union of Pure and Applied Physics (IUPAP). ; , s. 192-195
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- LOFAR (the Low Frequency Array), a distributed digital radio telescope with stations in the Netherlands, Germany, France, Sweden, and the United Kingdom, is designed to enable full-sky monitoring of transient radio sources. These capabilities are ideal for the detection of broadband radio pulses generated in cosmic ray air showers. The core of LOFAR consists of 24 stations within 4 square kilometers, and each station contains 96 low-band antennas and 48 high-band antennas. This dense instrumentation will allow detailed studies of the lateral distribution of the radio signal in a frequency range of 10-250 MHz. Such studies are key to understanding the various radio emission mechanisms within the air shower, as well as for determining the potential of the radio technique for primary particle identification. We present the status of the LOFAR cosmic ray program, including the station design and hardware, the triggering and filtering schemes, and our initial observations of cosmic-ray-induced radio pulses.
|
|
| 3. |
- Ding, Ding, et al.
(författare)
-
Perceived neighborhood environment and physical activity in 11 countries : Do associations differ by country?
- 2013
-
Ingår i: International Journal of Behavioral Nutrition and Physical Activity. - : Springer Science and Business Media LLC. - 1479-5868. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Increasing empirical evidence supports associations between neighborhood environments and physical activity. However, since most studies were conducted in a single country, particularly western countries, the generalizability of associations in an international setting is not well understood. The current study examined whether associations between perceived attributes of neighborhood environments and physical activity differed by country. Methods: Population representative samples from 11 countries on five continents were surveyed using comparable methodologies and measurement instruments. Neighborhood environment x country interactions were tested in logistic regression models with meeting physical activity recommendations as the outcome, adjusted for demographic characteristics. Country-specific associations were reported. Results: Significant neighborhood environment attribute x country interactions implied some differences across countries in the association of each neighborhood attribute with meeting physical activity recommendations. Across the 11 countries, land-use mix and sidewalks had the most consistent associations with physical activity. Access to public transit, bicycle facilities, and low-cost recreation facilities had some associations with physical activity, but with less consistency across countries. There was little evidence supporting the associations of residential density and crime-related safety with physical activity in most countries. Conclusion: There is evidence of generalizability for the associations of land use mix, and presence of sidewalks with physical activity. Associations of other neighborhood characteristics with physical activity tended to differ by country. Future studies should include objective measures of neighborhood environments, compare psychometric properties of reports across countries, and use better specified models to further understand the similarities and differences in associations across countries.
|
|
| 4. |
- Thoudam, Satyendra, et al.
(författare)
-
An air shower array for LOFAR : LORA
- 2011
-
Ingår i: Astrophysics and Space Sciences Transactions (ASTRA). - : Copernicus GmbH. - 1810-6528 .- 1810-6536. ; 7, s. 195-199
-
Tidskriftsartikel (refereegranskat)abstract
- LOFAR is a new form of radio telescope which can detect radio emission from air showers induced by very high-energy cosmic rays. It can also look for radio emission from particle cascades on the Moon induced by ultra high-energy cosmic rays or neutrinos. To complement the radio detection, we are setting up a small particle detector array LORA (LOfar Radboud Air shower array) within an area of ~300 m diameter in the LOFAR core. It will help in triggering and confirming the radio detection of air showers with the LOFAR antennas. In this paper, we present a short overview about LORA and discuss its current status.
|
|
| 5. |
- Adams, Marc A., et al.
(författare)
-
Patterns of neighborhood environment attributes related to physical activity across 11 countries : a latent class analysis
- 2013
-
Ingår i: International Journal of Behavioral Nutrition and Physical Activity. - : Springer Science and Business Media LLC. - 1479-5868. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Neighborhood environment studies of physical activity (PA) have been mainly single-country focused. The International Prevalence Study (IPS) presented a rare opportunity to examine neighborhood features across countries. The purpose of this analysis was to: 1) detect international neighborhood typologies based on participants' response patterns to an environment survey and 2) to estimate associations between neighborhood environment patterns and PA. Methods: A Latent Class Analysis (LCA) was conducted on pooled IPS adults (N=11,541) aged 18 to 64 years old (mean=37.5 +/- 12.8 yrs; 55.6% women) from 11 countries including Belgium, Brazil, Canada, Colombia, Hong Kong, Japan, Lithuania, New Zealand, Norway, Sweden, and the U. S. This subset used the Physical Activity Neighborhood Environment Survey (PANES) that briefly assessed 7 attributes within 10-15 minutes walk of participants' residences, including residential density, access to shops/services, recreational facilities, public transit facilities, presence of sidewalks and bike paths, and personal safety. LCA derived meaningful subgroups from participants' response patterns to PANES items, and participants were assigned to neighborhood types. The validated short-form International Physical Activity Questionnaire (IPAQ) measured likelihood of meeting the 150 minutes/week PA guideline. To validate derived classes, meeting the guideline either by walking or total PA was regressed on neighborhood types using a weighted generalized linear regression model, adjusting for gender, age and country. Results: A 5-subgroup solution fitted the dataset and was interpretable. Neighborhood types were labeled, "Overall Activity Supportive (52% of sample)", "High Walkable and Unsafe with Few Recreation Facilities (16%)", "Safe with Active Transport Facilities (12%)", "Transit and Shops Dense with Few Amenities (15%)", and "Safe but Activity Unsupportive (5%)". Country representation differed by type (e. g., U. S. disproportionally represented "Safe but Activity Unsupportive"). Compared to the Safe but Activity Unsupportive, two types showed greater odds of meeting PA guideline for walking outcome (High Walkable and Unsafe with Few Recreation Facilities, OR=2.26 (95% CI 1.18-4.31); Overall Activity Supportive, OR=1.90 (95% CI 1.13-3.21). Significant but smaller odds ratios were also found for total PA. Conclusions: Meaningful neighborhood patterns generalized across countries and explained practical differences in PA. These observational results support WHO/UN recommendations for programs and policies targeted to improve features of the neighborhood environment for PA.
|
|
| 6. |
- Velders, Matthijs A., et al.
(författare)
-
Prognosis of elderly patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention in 2001 to 2011 : a report from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) registry
- 2014
-
Ingår i: American Heart Journal. - : Elsevier. - 0002-8703 .- 1097-6744. ; 167:5, s. 666-673
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Elderly patients constitute a growing part of the population presenting with ST-elevation myocardial infarction (STEMI). The use of primary percutaneous coronary intervention (PCI) in this high-risk population remains poorly investigated.METHODS: Using the Swedish Coronary Angiography and Angioplasty Registry (SCAAR), we identified consecutive patients with STEMI 80 years or older undergoing primary PCI during a 10-year period. Temporal trends in care and 1-year prognosis were investigated, and long-term outcome was compared with a reference group of patients with STEMI aged 70 to 79 years. Relative survival was calculated by dividing the observed survival rate with the expected survival rate of the general population. Adjusted end points were calculated using Cox regression.RESULTS: In total, 4,876 elderly patients with STEMI were included. During the study period, average age and presence of comorbidity increased, as well as the use of antithrombotic therapy. Procedural success remained constant. One-year mortality was exclusively reduced between the most recent vs the earliest cohort, whereas the risk of reinfarction, heart failure, stroke, and bleeding remained similar. The risk of death was higher for elderly patients early after PCI, after which the prognosis was slightly better compared with the general population. Long-term risk of adverse events increased markedly with age.CONCLUSIONS: The prognosis of patients older than 80 years treated with primary PCI for STEMI was relatively unchanged during the 10-year inclusion period, despite changes in patient characteristics and treatment. Advanced age increased the risk of adverse events, but survivors of the early phase after PCI had a slightly improved prognosis compared with the general population.
|
|
