| 1. |
- Abbasi, R., et al.
(författare)
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Cosmic ray composition and energy spectrum from 1-30 PeV using the 40-string configuration of IceTop and IceCube
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 42, s. 15-32
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Tidskriftsartikel (refereegranskat)abstract
- The mass composition of high energy cosmic rays depends on their production, acceleration, and propagation. The study of cosmic ray composition can therefore reveal hints of the origin of these particles. At the South Pole, the IceCube Neutrino Observatory is capable of measuring two components of cosmic ray air showers in coincidence: the electromagnetic component at high altitude (2835 m) using the IceTop surface array, and the muonic component above ∼1 TeV using the IceCube array. This unique detector arrangement provides an opportunity for precision measurements of the cosmic ray energy spectrum and composition in the region of the knee and beyond. We present the results of a neural network analysis technique to study the cosmic ray composition and the energy spectrum from 1 PeV to 30 PeV using data recorded using the 40-string/40-station configuration of the IceCube Neutrino Observatory.
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| 2. |
- Abbasi, R., et al.
(författare)
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Searches for high-energy neutrino emission in the galaxy with the combined icecube-amanda detector
- 2013
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 763:1, s. 33-
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Tidskriftsartikel (refereegranskat)abstract
- We report on searches for neutrino sources at energies above 200 GeV in the Northern sky of the Galactic plane, using the data collected by the South Pole neutrino telescope, IceCube, and AMANDA. The Galactic region considered in this work includes the local arm toward the Cygnus region and our closest approach to the Perseus Arm. The searches are based on the data collected between 2007 and 2009. During this time AMANDA was an integrated part of IceCube, which was still under construction and operated with 22 strings (2007-2008) and 40 strings (2008-2009) of optical modules deployed in the ice. By combining the advantages of the larger IceCube detector with the lower energy threshold of the more compact AMANDA detector, we obtain an improved sensitivity at energies below ∼10 TeV with respect to previous searches. The analyses presented here are a scan for point sources within the Galactic plane, a search optimized for multiple and extended sources in the Cygnus region, which might be below the sensitivity of the point source scan, and studies of seven pre-selected neutrino source candidates. For one of them, Cygnus X-3, a time-dependent search for neutrino emission in coincidence with observed radio and X-ray flares has been performed. No evidence of a signal is found, and upper limits are reported for each of the searches. We investigate neutrino spectra proportional to E -2 and E -3 in order to cover the entire range of possible neutrino spectra. The steeply falling E -3 neutrino spectrum can also be used to approximate neutrino energy spectra with energy cutoffs below 50 TeV since these result in a similar energy distribution of events in the detector. For the region of the Galactic plane visible in the Northern sky, the 90% confidence level muon neutrino flux upper limits are in the range E 3 dN/dE ∼ 5.4-19.5 × 10-11 TeV2 cm-2 s-1 for point-like neutrino sources in the energy region [180.0 GeV-20.5 TeV]. These represent the most stringent upper limits for soft-spectra neutrino sources within the Galaxy reported to date.
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| 3. |
- Abbasi, R., et al.
(författare)
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An improved method for measuring muon energy using the truncated mean of dE/dx
- 2013
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 703, s. 190-198
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of muon energy is critical for many analyses in large Cherenkov detectors, particularly those that involve separating extraterrestrial neutrinos from the atmospheric neutrino background. Muon energy has traditionally been determined by measuring the specific energy loss (dE/dx) along the muon's path and relating the dE/dx to the muon energy. Because high-energy muons (Eμ>1TeV) lose energy randomly, the spread in dE/dx values is quite large, leading to a typical energy resolution of 0.29 in log10(Eμ) for a muon observed over a 1 km path length in the IceCube detector. In this paper, we present an improved method that uses a truncated mean and other techniques to determine the muon energy. The muon track is divided into separate segments with individual dE/dx values. The elimination of segments with the highest dE/dx results in an overall dE/dx that is more closely correlated to the muon energy. This method results in an energy resolution of 0.22 in log10(Eμ), which gives a 26% improvement. This technique is applicable to any large water or ice detector and potentially to large scintillator or liquid argon detectors.
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| 4. |
- Goey, Kaitlyn K. H., et al.
(författare)
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Reporting of patient characteristics and stratification factors in phase 3 trials investigating first-line systemic treatment of metastatic colorectal cancer : A systematic review
- 2018
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049 .- 1879-0852. ; 96, s. 115-124
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Forskningsöversikt (refereegranskat)abstract
- Background: Patient characteristics and stratification factors are important factors influencing trial outcomes. Uniform reporting on these parameters would facilitate cross-study comparisons and extrapolation of trial results to clinical practice. In 2007, standardisation on patient characteristics reporting and stratification in metastatic colorectal cancer (mCRC) trials was proposed. We investigated the reporting of prognostic factors and implementation of this proposal in mCRC trials published from 2005 to 2016.Methods: We searched PubMed and Embase (January 2005 – June 2016) for first-line phase 3 mCRC trials. Patient characteristics reporting and use of stratification factors were extracted and analysed for adherence to the proposal from 2007.Results: Sixty-seven trials (35,315 patients) were identified, reporting 48 different patient characteristics (median: 9 [range: 5–18] per study). Age, gender, performance status (PS), primary tumour site and adjuvant chemotherapy were frequently reported (87%–100%), in contrast to laboratory values, such as alkaline phosphatase, lactate dehydrogenase and white blood cell count (10%–25%). We identified 29 different stratification factors (median: 3 [range: 1–9] per study). The most common strata were PS and treatment centre (>60%). A median of 8/12 (range: 4–11) of the proposed parameters was reported. Although the percentage of studies reporting each factor slightly increased over time, there was no significant correlation between publication year and adherence to the proposal from 2007.Conclusions: We observed persistent heterogeneity in the reporting of patient characteristics and use of stratification factors in first-line mCRC trials. The proposal from 2007 has not led to increased uniformity of patient characteristics reporting and use of stratification over time. There is an urgent need to address this issue to improve the interpretation of trial results.
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| 5. |
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| 6. |
- Sorbye, H., et al.
(författare)
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Patient characteristics and stratification in medical treatment studies for metastatic colorectal cancer : a proposal for standardization of patient characteristic reporting and stratification
- 2007
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 18:10, s. 1666-1672
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prognostic factors have the potential to determine the survival of patients to a greater extent than current antineoplastic agents. Despite this knowledge, there is no consensus on, first, what patient characteristics to report and, second, what stratification factors to use in metastatic colorectal cancer trials. Patients and methods: Seven leading oncology and medical journals were reviewed for phase II and III publications reporting on medical treatment of metastatic colorectal cancer patients during 2001–2005. One hundred and forty-three studies with 21 214 patients were identified. The reporting of patient characteristics and use of stratification was noted. Results: Age, gender, performance status, metastases location, sites and adjuvant chemotherapy were often reported (99–63%). Laboratory values as alkaline phosphatase, lactate dehydrogenase and white blood cell count, repeatedly found to be of prognostic relevance, were rarely reported (5–9%). Stratification was used in all phase III trials; however, only study centre was used with any consistency. Conclusion: There is considerable inconsistency in the reporting of patient characteristics and use of stratification factors in metastatic colorectal cancer trials. We propose a standardization of patient characteristics reporting and stratification factors. A common set of characteristics and strata will aid in trial reporting, interpretation and future meta-analyses.
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