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| 2. |
- Di Fatta, G., et al.
(författare)
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Preface
- 2011
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Ingår i: IEEE International Conference on Data Mining. Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 1550-4786. ; , s. xlviii-xlvix
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Hassler, B., et al.
(författare)
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Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability
- 2014
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:5, s. 1395-1427
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Tidskriftsartikel (refereegranskat)abstract
- Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid- to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified. In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available. This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given.
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| 4. |
- Granville, S, et al.
(författare)
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Optical conductivity and x-ray absorption and emission study of the band structure of MnN films
- 2005
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 72:20, s. 205127-
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Tidskriftsartikel (refereegranskat)abstract
- The band structure of MnN films prepared by ion assisted deposition has been investigated by optical conductivity and x-ray absorption and emission spectroscopies. X-ray diffraction and extended x-ray absorption fine structure show the films to be nanocrystalline but phase pure and exhibiting the known antiferromagnetic distorted rocksalt phase. X-ray emission spectroscopy of the N K-edge and x-ray absorption near edge spectroscopy of both the N K- and Mn L-edges are used to probe the occupied and empty densities of states, which compare well with the N(2p) and Mn(3d) partial densities of states calculated using the linearized muffin-tin orbital band structure method. A similar comparison is made between the measured optical conductivity and the calculated contribution from interband transitions. It is possible to associate the main features in the measured spectrum with corresponding ones in the calculated optical function. The major differences between calculated and measured spectra can be understood on the basis of a limited electron mean-free-path in these nanocrystalline films, which broadens the features in the joint density of states and relaxes the momentum conservation requirement. The calculated optical functions are analyzed in detail in terms of their dominant band-to-band contributions and in addition the polarization dependence is predicted. Temperature dependent conductivity measurements are also reported and show a clear metallic behavior and a weak Kondo-like low temperature anomaly.
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| 5. |
- Kerstens, Vera S, et al.
(författare)
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Reliability of dopamine transporter PET measurements with [18F]FE-PE2I in patients with Parkinson's disease.
- 2020
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Ingår i: EJNMMI Research. - : Springer Nature. - 2191-219X. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reliable quantification of dopamine transporter (DAT), a biomarker for Parkinson's disease (PD), is essential for diagnostic purposes as well as for evaluation of potential disease-modifying treatment. Due to degeneration of dopaminergic neurons and thus lower expected radioligand binding to DAT, higher measurement variability in PD patients might be expected than earlier reproducibility results in healthy controls. Therefore, we aimed to examine the test-retest properties of [18F]FE-PE2I-PET in PD patients.METHODS: Nine patients with PD (Hoehn and Yahr stage < 3) were included (men/women 6/3; mean age 65.2 ± 6.8 years). Each patient underwent two [18F]FE-PE2I-PET measurements within 7-28 days. The outcome measure was non-displaceable binding potential generated using wavelet-aided parametric imaging with cerebellum as reference region. We assessed test-retest performance using estimates of reliability and repeatability. Regions for primary analysis were caudate, putamen, ventral striatum, and substantia nigra. Exploratory analysis was performed for functional subdivisions of the striatum. We also compared the more vs. less affected side.RESULTS: [18F]FE-PE2I showed absolute variability estimates of 5.3-7.6% in striatal regions and 11% in substantia nigra and ICCs of 0.74-0.97 (median 0.91). The absolute variability for functional striatal subdivisions was 6.0-9.6% and ICCs of 0.76-0.91 (median 0.91). The less affected substantia nigra exhibited greater consistency than the more affected side. According to power calculations based on the current sample size, DAT changes of 5-11% in the striatum and 28% in the substantia nigra can be detected with a power of 0.8 (p < 0.0125).CONCLUSION: DAT-PET measurements with [18F]FE-PE2I in PD patients showed good repeatability and reliability. The slightly lower reliability in the substantia nigra in patients may be explained by lower DAT density and smaller anatomical size. Power calculations suggest that [18F]FE-PE2I PET is a suitable marker for longitudinal DAT decline in PD.TRIAL REGISTRATION: EudraCT 2017-003327-29.
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| 6. |
- Knudsen, Gitte M, et al.
(författare)
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Guidelines for the content and format of PET brain data in publications and archives : A consensus paper
- 2020
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 40:8, s. 1576-1585
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Tidskriftsartikel (refereegranskat)abstract
- It is a growing concern that outcomes of neuroimaging studies often cannot be replicated. To counteract this, the magnetic resonance (MR) neuroimaging community has promoted acquisition standards and created data sharing platforms, based on a consensus on how to organize and share MR neuroimaging data. Here, we take a similar approach to positron emission tomography (PET) data. To facilitate comparison of findings across studies, we first recommend publication standards for tracer characteristics, image acquisition, image preprocessing, and outcome estimation for PET neuroimaging data. The co-authors of this paper, representing more than 25 PET centers worldwide, voted to classify information as mandatory, recommended, or optional. Second, we describe a framework to facilitate data archiving and data sharing within and across centers. Because of the high cost of PET neuroimaging studies, sample sizes tend to be small and relatively few sites worldwide have the required multidisciplinary expertise to properly conduct and analyze PET studies. Data sharing will make it easier to combine datasets from different centers to achieve larger sample sizes and stronger statistical power to test hypotheses. The combining of datasets from different centers may be enhanced by adoption of a common set of best practices in data acquisition and analysis.
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| 7. |
- McGoohan, K, et al.
(författare)
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A Preliminary Investigation of the Views of People With Parkinson's (With and Without Psychosis) and Caregivers on Participating in Clinical Trials During the Covid-19 Pandemic: An Online Survey
- 2020
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Ingår i: Frontiers in psychiatry. - : Frontiers Media SA. - 1664-0640. ; 11, s. 602480-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The coronavirus pandemic is having a profound impact on non-COVID-19 related research, including the delivery of clinical trials for patients with Parkinson's disease.Objectives: A preliminary investigation to explore the views of Parkinson's disease (PD) patients, with and without experience of psychosis symptoms, and carers on the resumption of clinical research and adaptations to trials in light of COVID-19.Methods: An anonymous self-administered online survey was completed by 30 PD patients and six family members/carers via the Parkinson's UK Research Support Network to explore current perceptions on taking part in PD research and how a planned clinical trial for psychosis in PD may be adapted so participants feel safe.Results: Ninety-one percent of respondents were enthusiastic about the continuation of non-COVID-19 related research as long as certain safety measures were in place. Ninety-four percent stated that they would be happy to complete assessments virtually. However, they noted that care should be taken to ensure that this does not exclude participants, particularly those with more advanced PD who may require assistance using portable electronic devices. Regular and supportive communication from the research team was also seen as important for maintaining the psychological well-being of participants while taking part in the trial.Conclusions: In the era of COVID-19 pandemic, standard approaches will have to be modified and rapid adoption of virtual assessments will be critical for the continuation of clinical research. It is important that alongside the traditional methods, new tools are developed, and older ones validated for virtual assessments, to allow safe and comprehensive assessments vital for ongoing research in people with Parkinson's.
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