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| 2. |
- Abdalla, H., et al.
(författare)
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TeV Emission of Galactic Plane Sources with HAWC and HESS
- 2021
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 917:1
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Tidskriftsartikel (refereegranskat)abstract
- The High Altitude Water Cherenkov (HAWC) observatory and the High Energy Stereoscopic System (H.E.S.S.) are two leading instruments in the ground-based very-high-energy gamma-ray domain. HAWC employs the water Cherenkov detection (WCD) technique, while H.E.S.S. is an array of Imaging Atmospheric Cherenkov Telescopes (IACTs). The two facilities therefore differ in multiple aspects, including their observation strategy, the size of their field of view, and their angular resolution, leading to different analysis approaches. Until now, it has been unclear if the results of observations by both types of instruments are consistent: several of the recently discovered HAWC sources have been followed up by IACTs, resulting in a confirmed detection only in a minority of cases. With this paper, we go further and try to resolve the tensions between previous results by performing a new analysis of the H.E.S.S. Galactic plane survey data, applying an analysis technique comparable between H.E.S.S. and HAWC. Events above 1 TeV are selected for both data sets, the point-spread function of H.E.S.S. is broadened to approach that of HAWC, and a similar background estimation method is used. This is the first detailed comparison of the Galactic plane observed by both instruments. H.E.S.S. can confirm the gamma-ray emission of four HAWC sources among seven previously undetected by IACTs, while the three others have measured fluxes below the sensitivity of the H.E.S.S. data set. Remaining differences in the overall gamma-ray flux can be explained by the systematic uncertainties. Therefore, we confirm a consistent view of the gamma-ray sky between WCD and IACT techniques.
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| 3. |
- Gonzalez-Ortiz, Fernando, et al.
(författare)
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A novel ultrasensitive assay for plasma p-tau217: Performance in individuals with subjective cognitive decline and early Alzheimer's disease.
- 2024
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - 1552-5279. ; 20:2, s. 1239-1249
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Tidskriftsartikel (refereegranskat)abstract
- Detection of Alzheimer's disease (AD) pathophysiology among individuals with mild cognitive changesand those experiencing subjective cognitive decline (SCD) remains challenging. Plasma phosphorylated tau 217 (p-tau217) is one of the most promising of the emerging biomarkers for AD. However, accessible methods are limited.We employed a novel p-tau217 immunoassay (University of Gothenburg [UGOT] p-tau217) in four independent cohorts (n=308) including a cerebrospinal fluid (CSF) biomarker-classified cohort (Discovery), two cohorts consisting mostly of cognitively unimpaired (CU) and mild cognitively impaired (MCI) participants (MYHAT and Pittsburgh), and a population-based cohort of individuals with SCD (Barcelonaβeta Brain Research Center's Alzheimer's At-Risk Cohort [β-AARC]).UGOT p-tau217 showed high accuracy (area under the curve [AUC]=0.80-0.91) identifying amyloid beta (Aβ) pathology, determined either by Aβ positron emission tomography or CSF Aβ42/40 ratio. In individuals experiencing SCD, UGOT p-tau217 showed high accuracy identifying those with a positive CSF Aβ42/40 ratio (AUC=0.91).UGOT p-tau217 can be an easily accessible and efficient way to screen and monitor patients with suspected AD pathophysiology, even in the early stages of the continuum.
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| 4. |
- Gonzalez-Ortiz, Fernando, et al.
(författare)
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A novel ultrasensitive assay for plasma p-tau217: performance in individuals with subjective cognitive decline and early Alzheimer's disease.
- 2023
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Ingår i: medRxiv : the preprint server for health sciences.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Detection of Alzheimer's disease (AD) pathophysiology among cognitively unimpaired individuals and those experiencing subjective cognitive decline (SCD) remains challenging. Plasma p-tau217 is one of the most promising of the emerging biomarkers for AD. However, accessible methods are limited.We employed a novel p-tau217 immunoassay (UGOT p-tau217) in four independent cohorts (n=308) including a cerebrospinal fluid (CSF) biomarker-classified cohort (Discovery), two cohorts consisting mostly of cognitively unimpaired participants (MYHAT and Pittsburgh), and a population-based cohort of individuals with SCD (β-AARC).UGOT p-tau217 showed high accuracy (AUC= 0.80-0.91) identifying Aβ pathology, determined either by Aβ positron emission tomography or CSF Aβ42/40 ratio. In individuals experiencing SCD, UGOT p-tau217 showed high accuracy identifying those with a positive CSF Aβ42/40 ratio (AUC= 0.91).UGOT p-tau217 can be an easily accessible and efficient way to screen and monitor patients with suspected AD pathophysiology, even in the early stages of the continuum.
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| 5. |
- Abdalla, H., et al.
(författare)
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HESS and MAGIC observations of a sudden cessation of a very-high-energy gamma-ray flare in PKS 1510-089 in May 2016
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 648
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Tidskriftsartikel (refereegranskat)abstract
- The flat spectrum radio quasar (FSRQ) PKS 1510-089 is known for its complex multiwavelength behaviour and it is one of only a few FSRQs detected in very-high-energy (VHE, E>100 GeV) gamma rays. The VHE gamma -ray observations with H.E.S.S. and MAGIC in late May and early June 2016 resulted in the detection of an unprecedented flare, which revealed, for the first time, VHE gamma -ray intranight variability for this source. While a common variability timescale of 1.5 h has been found, there is a significant deviation near the end of the flare, with a timescale of similar to 20 min marking the cessation of the event. The peak flux is nearly two orders of magnitude above the low-level emission. For the first time, a curvature was detected in the VHE gamma -ray spectrum of PKS 1510-089, which can be fully explained by the absorption on the part of the extragalactic background light. Optical R-band observations with ATOM revealed a counterpart of the gamma -ray flare, even though the detailed flux evolution differs from the VHE gamma -ray light curve. Interestingly, a steep flux decrease was observed at the same time as the cessation of the VHE gamma -ray flare. In the high-energy (HE, E> 100 MeV) gamma -ray band, only a moderate flux increase was observed with Fermi-LAT, while the HE gamma -ray spectrum significantly hardens up to a photon index of 1.6. A search for broad-line region (BLR) absorption features in the gamma -ray spectrum indicates that the emission region is located outside of the BLR. Radio very-long-baseline interferometry observations reveal a fast-moving knot interacting with a standing jet feature around the time of the flare. As the standing feature is located similar to 50 pc from the black hole, the emission region of the flare may have been located at a significant distance from the black hole. If this is indeed a true correlation, the VHE gamma rays must have been produced far down in the jet, where turbulent plasma crosses a standing shock.
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| 6. |
- Algaba, Juan-Carlos, et al.
(författare)
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
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Forskningsöversikt (refereegranskat)abstract
- In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
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| 7. |
- Jones, Benedict C, et al.
(författare)
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To which world regions does the valence-dominance model of social perception apply?
- 2021
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Ingår i: Nature Human Behaviour. - : Springer Science and Business Media LLC. - 2397-3374. ; 5:1, s. 159-169
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Tidskriftsartikel (refereegranskat)abstract
- Over the past 10 years, Oosterhof and Todorov's valence-dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgements of faces. Because this model has primarily been developed and tested in Western regions, it is unclear whether these findings apply to other regions. We addressed this question by replicating Oosterhof and Todorov's methodology across 11 world regions, 41 countries and 11,570 participants. When we used Oosterhof and Todorov's original analysis strategy, the valence-dominance model generalized across regions. When we used an alternative methodology to allow for correlated dimensions, we observed much less generalization. Collectively, these results suggest that, while the valence-dominance model generalizes very well across regions when dimensions are forced to be orthogonal, regional differences are revealed when we use different extraction methods and correlate and rotate the dimension reduction solution. PROTOCOL REGISTRATION: The stage 1 protocol for this Registered Report was accepted in principle on 5 November 2018. The protocol, as accepted by the journal, can be found at https://doi.org/10.6084/m9.figshare.7611443.v1 .
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| 9. |
- Navarro Suárez, Adriana, 1983, et al.
(författare)
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Poly(quinone-amine)/nanocarbon composite electrodes with enhanced proton storage capacity
- 2017
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 5:44, s. 23292-23298
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Tidskriftsartikel (refereegranskat)abstract
- Novel redox active bi- and terpolymers, containing quinone-amine blocks and wired by nanocarbons have been synthesized and studied as negative electrodes for electrochemical proton storage. Two kinds of diamine (aliphatic and aromatic) were condensed with benzoquinone to enhance the storage capacity. The reaction between the benzoquinone and the diamines created an electroactive polymer displaying pseudo-faradaic proton transfer processes. Besides this transfer process, the aromatic diamine showed an additional reversible redox reaction, between the nitrogen atoms conjugated to the quinone molecule and the hydrogen ions. The incorporation of carbon conductive nanofillers with specific dimensionality provided an additional and straightforward strategy to maximize both the electron conductivity and the proton storage capacity of the polymers. Homogeneous dispersion of nanocarbon redox polymer particles in the composite (along with the creation of a polymer-carbon interphase) was essential, in order to maximize the proton storage capacity. A clear correlation between the nanostructure of the polymer particles, the dimensionality of the nanocarbons and the polymerization process was found. These low-cost redox polymers reached up to 230 mA h g-1 and 75 ?A h cm-2 at 0.08 A g-1 in an aqueous-based electrolyte, paving the way for the use of these materials for technologies such as thin-film devices and grid energy storage.
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| 10. |
- Nelldal, Bo-Lennart, 1946-
(författare)
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Requirements toward the freight system of 2030/2050 : Capacity4Rail Deliverable 21.2, EC Contract No FP7- 605650
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The total demand for freight in Europe has increased rapidly in recent decades, but rail freight has lost market share and most of the increase has been handled by trucks. In the last decade, rail markets share has increased in some countries because of deregulation, investments in rail and truck fees, but is still very low in many countries. In the new member states the markets have decreased rapidly when rail monopoly has been taken away.Rail deregulation has not been implemented in practice in all countries while at the same time truck deregulation has been implemented fully and resulted in a low-cost truck market. Moreover, the cost of external effects has not yet been implemented. Most forecasts show an increase of 60% in total freight demand by 2050 and an approximately constant market share with a business-as-usual scenario. To fulfil the targets in the EU white paper, it is necessary to roughly double rails’ market share from 18% in 2011 to at least 36% in 2050. This means that the tonne-kilometres will be 3.6 times as much as today and 2.4 times as much as in a business-as-usual scenario in 2050.To reach the white paper target, it is necessary to both increase quality and capacity and lower the cost of rail freight. The customers must be able to trust the delivery time to meet the requirements of their logistic chain and the cost must be competitive with road freight. A system approach is therefore needed and the critical development lines must be identified. From the customer’s transportation needs that put demands on the wagons – the wagons are coupled together into trains where available tractive power is taken into account – the train utilises the infrastructure with a certain performance along a link and ultimately in a network from origin to destination.Much of today’s freight train system and infrastructure is based on an old standard 3-4 MW locomotive that means trains of approximately 1,500 gross tonnes and a train length of 650-750 metres. But modern locomotives have a tractive power of 5-6 MW capable of hauling 2,000-2,500 tonne trains of up to 1,000m in length. In Europe, train lengths up to 850m already exist and experiments have been made with 2x750m=1,500m long trains with radio-controlled locomotives in the middle of the train. Not only the tractive power but also the locomotives’ axle load is critical for optimal traction. To increase the axle load from normally around 20 tonnes to 22.5 or for heavy haul, 25-30 tonnes is a possibility to operate heavier trains combined with track-friendly bogies.Concerning the wagons, one important question is whether development will be incremental, as it has been so far, or if it is possible to make a system change. An incremental change means successively higher axle loads, wider gauge, better length-utilization in a given train length, higher payload and less tare weight per wagon, more silent brake-blocks, end of train devices and some electronic sensors. A system change will include electro-pneumatic brakes, disc-brakes, full electronic control of the wagons and load and automatic central couplers. The automatic couplers is the most critical component but important not only because it will make shunting and marshalling safer and cheaper but also because it will make it possible to operate longer trains without problems and introduce electronic braking systems and control and to feed the train with electricity.Today, most rail operators use electric locos for long haul and diesel locos for feeder transport and terminal shunting. But the duo-loco has now been introduced into the markets, equipped with both normal electric traction and diesel traction, either for shunting or for line haul. This means that a duo-loco can shunt the wagons itself at a marshalling yard or stop at an un-electrified siding at an industry and change wagons directly. The operators thus need only one loco instead of two and it will also make it possible to introduce new operation principles and change wagons along the line. It will also decrease vulnerability in case of current interruptions. In the long term, it will also make it possible to avoid catenaries at marshalling yards and sidings, which will save money for the IM.Also for intermodal it is an advantage to introduce liner trains. If the terminals are located on an electrified side track where the train can drive straight in and out onto the line again, there is no need for a diesel loco to be switched in. This in turn requires a horizontal transfer technology that can function under the overhead contact wires. The train must be able to be loaded and unloaded during a stop of 15-30 minutes. This also obviates the need to park wagons. The terminals can also be made more compact and require less space. This will reduce the costs which is critical for intermodal.Most trailers today are not designed to be lifted onto a railway wagon. The trailer market is in practice therefore very limited even at conventional intermodal terminals that have lifting equipment. Solutions where trailers do not need to be lifted but can be rolled on and off along a ramp can thus widen the market considerably. They also mean that simple terminals only need to be dimensioned for the trucks’ axle load.To increase the capacity of the rail system, the following measures can be taken: (1) More efficient timetable planning: On double track: Bundling of trains with the same average speed in timetable channels to harmonize speeds. During the day faster freight trains are an option. (2) Use of trains and vehicles with higher capacity: For freight: Longer trains, higher and wider gauge, higher axle load and metre load. For passenger trains: Double-decker and wide-body trains. (3) Differentiation of track access charges to avoid peak hours and overloaded links. (4) Better signalling system, shorter block lengths and in the long term introduction of ERTMS level 3. (5) Adaptation of freight corridors for long and heavy freight trains. (6). Investment in HSR to increase capacity for freight trains and regional trains on the conventional network and in some cases dedicated freight railways.Two targets in the EU white paper at 2011 were that 30% of road freight over 300 km should shift to other modes such as rail or waterborne transport by 2030, and to triple the length of the existing high-speed rail network by 2030. For high speed rail the target seems to be achievable. The actual development of freight is not in line with the target and at present there are no indications that it will be fulfilled. The planned Rail Freight Corridors (RFC) are promising but there is no common plan to increase the standard in the RFC, which would be desirable. With the measures listed above, longer and heavier trains will make it possible to roughly double the capacity for freight trains without building new railways and in the long term with ERTMS level 3 even more.It is possible to reduce GHG emissions for all modes but rail will still be the most efficient mode by 2050. An estimation of the effects of a mode shift to rail transport applying the world’s ‘best practice’ shows that such a mode shift to rail can reduce EU transport GHG emissions over land by about 20 %, compared with a baseline scenario. In combination with low-carbon electricity production a reduction of about 30% may be achieved. A developed rail system can thus substantially contribute to the EU target of reducing GHG emissions in the transport sector by 60% compared to 1990 levels. To enable such a mode shift and to manage the demand for capacity, there is a need for investment. This will also maintain and increase mobility for passengers and freight.
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