| 1. |
- Watts, Anna L., et al.
(författare)
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Dense matter with eXTP
- 2019
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Ingår i: Science China Physics, Mechanics & Astronomy. - : Science Press. - 1674-7348 .- 1869-1927. ; 62:2
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Forskningsöversikt (refereegranskat)abstract
- In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is expected to be launched in the mid 2020s.
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| 2. |
- Xu, Guobao, et al.
(författare)
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Tree ring O-18's indication of a shift to a wetter climate since the 1880s in the western Tianshan Mountains of northwestern China
- 2015
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 120:13, s. 6409-6425
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Tidskriftsartikel (refereegranskat)abstract
- Central Asian droughts have drastically and significantly affected agriculture and water resource management in these arid and semiarid areas. Based on tree ring O-18 from native, dominant Schrenk spruce (Picea schrenkiana Fisch. et Mey.), we developed a 300year (1710-2010) standard precipitation-evaporation index (SPEI) reconstruction from January to August for China's western Tianshan Mountains. The regression model explained 37.6% of the variation in the SPEI reconstruction during the calibration period from 1950 to 2010. Comparison with previous drought reconstructions confirmed the robustness of our reconstruction. The 20th century has been a relatively wet period during the past 300years. The SPEI showed quasi 2, 5, and 10year cycles. Several pluvials and droughts with covariability over large areas were revealed clearly in the reconstruction. The two longest pluvials (lasting for 12years), separated by 50years, appeared in the 1900s and the 1960s. The most severe drought occurred from 1739 to 1761 and from 1886 to 1911 was the wettest period since 1710. Compared to previous investigations of hydroclimatic changes in the western Tianshan Mountains, our reconstruction revealed more low-frequency variability and indicated that climate in the western Tianshan Mountains shifted from dry to wet in 1886. This regime shift was generally consistent with other moisture reconstructions for the northeastern Tibetan Plateau and northern Pakistan and may have resulted from a strengthened westerly circulation. The opposite hydrological trends in the western Tianshan Mountains and southeastern Tibetan Plateau reveal a substantial influence of strengthened westerlies and weakening of the Indian summer monsoon.
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| 3. |
- Xu, Guobao, et al.
(författare)
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Century-scale temperature variability and onset of industrial-era warming in the Eastern Tibetan Plateau
- 2019
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 53:7-8, s. 4569-4590
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Tidskriftsartikel (refereegranskat)abstract
- To improve our understanding of climate variability in the Tibetan Plateau (TP) and its sensitivity to external forcings, recent temperature changes need to be placed in a long-term historical context. Here, we present two tree-ring based temperature reconstructions: a 1003-year (1000-2002 CE) annual temperature reconstruction for the northeastern TP (NETP) based on seven series and a 522-year (1489-2010 CE) summer (June-July-August) temperature reconstruction for the southeastern TP (SETP) based on 11 series. Our reconstructions show six centuries of generally warm NETP temperatures (1000-1586 CE), followed by a transition to cooler temperatures (1587-1887 CE for NETP and 1588-1930 CE for SETP). The transition from the Medieval Climate Anomaly to the Little Ice Age thus happened in the 1580s in NETP and SETP, which is about 150 years later than in larger-scale (e.g. Asia and the Northern Hemisphere) temperature reconstructions. We found that TP temperature variability, especially in SETP, was influenced by the Atlantic multi-decadal oscillation and that the twentieth century was the warmest on record in NETP and SETP. Our reconstructions and climate model simulations both show industrial-era warming trends, the onset of which happened earlier in NETP (1812 CE) compared to SETP (1887 CE) and other temperature reconstructions for Western China, East Asia, Asia, and the Northern Hemisphere. The early NETP onset of industrial-era warming can likely be explained by NETP's faster warming rate and by local feedback factors (i.e., ice-snow cover-albedo). Comparisons between climate model simulations and our reconstructions reveal that cooler TP temperatures from 1600 to 1800 CE might be related to land-use and land-cover change.
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| 4. |
- Semakula, Henry Musoke, et al.
(författare)
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Prediction of future malaria hotspots under climate change in sub-Saharan Africa
- 2017
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 143:3-4, s. 415-428
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Tidskriftsartikel (refereegranskat)abstract
- Malaria is a climate sensitive disease that is causing rampant deaths in sub-Saharan Africa (SSA) and its impact is expected to worsen under climate change. Thus, pre-emptive policies for future malaria control require projections based on integrated models that can accommodate complex interactions of both climatic and non-climatic factors that define malaria landscape. In this paper, we combined Geographical Information System (GIS) and Bayesian belief networks (BBN) to generate GIS-BBN models that predicted malaria hotspots in 2030, 2050 and 2100 under representative concentration pathways (RCPs) 4.5 and 8.5. We used malaria data of children of SSA, gridded environmental and social-economic data together with projected climate data from the 21 Coupled Model Inter-comparison Project Phase 5 models to compile the GIS-BBN models. Our model on which projections were made has an accuracy of 80.65% to predict the high, medium, low and no malaria prevalence categories correctly. The non-spatial BBN model projection shows a moderate variation in malaria reduction for the high prevalence category among RCPs. Under the low prevalence category, an increase in malaria is seen but with little variation ranging between 4.6 and 5.6 percentage points. Spatially, under RCP 4.5, most parts of SSA will have medium malaria prevalence in 2030, while under RCP 8.5, most parts will have no malaria except in the highlands. Our BBN-GIS models show an overall shift of malaria hotspots from West Africa to the eastern and southern parts of Africa especially under RCP 8.5. RCP 8.5 will not expand the high and medium malaria prevalence categories in all the projection years. The generated probabilistic maps highlight future malaria hotspots under climate change on which pre-emptive policies can be based.
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| 5. |
- Wang, Hui, et al.
(författare)
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On the Structure of alpha-BiFeO3
- 2013
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 52:5, s. 2388-2392
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline and monocrystalline alpha-BiFeO3 crystals have been synthesized by solid state reaction and flux growth method, respectively. X-ray, neutron, and electron diffraction techniques are used to study the crystallographic and magnetic structure of alpha-BiFeO3. The present data show that alpha-BiFeO3 crystallizes in space group PI with a = 0.563 17(1) nm, b = 0.563 84(1) nm, c = 0.563 70(1) nm, alpha = 59.33(1)degrees, beta = 59.35(1)degrees, gamma = 59.38(1)degrees, and the magnetic structure of alpha-BiFeO3 can be described by space group PI with magnetic modulation vector in reciprocal space q = 0.0045a* - 0.0045b*, which is the magnetic structure model proposed by I. Sosnowska(1) applied to the new PI crystal symmetry of alpha-BiFeO3
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