| 1. |
|
|
| 2. |
- Mattsson, Niklas, 1979, et al.
(författare)
-
The Alzheimer's Association external quality control program for cerebrospinal fluid biomarkers.
- 2011
-
Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 7:4
-
Tidskriftsartikel (refereegranskat)abstract
- The cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ)-42, total-tau (T-tau), and phosphorylated-tau (P-tau) demonstrate good diagnostic accuracy for Alzheimer's disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories. The Alzheimer's Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch-to-batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program.
|
|
| 3. |
- Giosan, Liviu, et al.
(författare)
-
Fluvial landscapes of the Harappan civilization
- 2012
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:26, s. E1688-E1694
-
Tidskriftsartikel (refereegranskat)abstract
- The collapse of the Bronze Age Harappan, one of the earliest urban civilizations, remains an enigma. Urbanism flourished in the western region of the Indo-Gangetic Plain for approximately 600 y, but since approximately 3,900 y ago, the total settled area and settlement sizes declined, many sites were abandoned, and a significant shift in site numbers and density towards the east is recorded. We report morphologic and chronologic evidence indicating that fluvial landscapes in Harappan territory became remarkably stable during the late Holocene as aridification intensified in the region after approximately 5,000 BP. Upstream on the alluvial plain, the large Himalayan rivers in Punjab stopped incising, while downstream, sedimentation slowed on the distinctive mega-fluvial ridge, which the Indus built in Sindh. This fluvial quiescence suggests a gradual decrease in flood intensity that probably stimulated intensive agriculture initially and encouraged urbanization around 4,500 BP. However, further decline in monsoon precipitation led to conditions adverse to both inundation- and rain-based farming. Contrary to earlier assumptions that a large glacier-fed Himalayan river, identified by some with the mythical Sarasvati, watered the Harappan heartland on the interfluve between the Indus and Ganges basins, we show that only monsoonal-fed rivers were active there during the Holocene. As the monsoon weakened, monsoonal rivers gradually dried or became seasonal, affecting habitability along their courses. Hydroclimatic stress increased the vulnerability of agricultural production supporting Harappan urbanism, leading to settlement downsizing, diversification of crops, and a drastic increase in settlements in the moister monsoon regions of the upper Punjab, Haryana, and Uttar Pradesh.
|
|
| 4. |
- Glasser, Neil F., et al.
(författare)
-
Glacial lake drainage in Patagonia (13-8 kyr) and response of the adjacent Pacific Ocean
- 2016
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Large freshwater lakes formed in North America and Europe during deglaciation following the Last Glacial Maximum. Rapid drainage of these lakes into the Oceans resulted in abrupt perturbations in climate, including the Younger Dryas and 8.2 kyr cooling events. In the mid-latitudes of the Southern Hemisphere major glacial lakes also formed and drained during deglaciation but little is known about the magnitude, organization and timing of these drainage events and their effect on regional climate. We use 16 new single-grain optically stimulated luminescence (OSL) dates to define three stages of rapid glacial lake drainage in the Lago General Carrera/Lago Buenos Aires and Lago Cohrane/Pueyrredon basins of Patagonia and provide the first assessment of the effects of lake drainage on the Pacific Ocean. Lake drainage occurred between 13 and 8 kyr ago and was initially gradual eastward into the Atlantic, then subsequently reorganized westward into the Pacific as new drainage routes opened up during Patagonian Ice Sheet deglaciation. Coupled ocean-atmosphere model experiments using HadCM3 with an imposed freshwater surface hosing to simulate glacial lake drainage suggest that a negative salinity anomaly was advected south around Cape Horn, resulting in brief but significant impacts on coastal ocean vertical mixing and regional climate.
|
|
| 5. |
- Harrison, Stephan, et al.
(författare)
-
Early and mid-Holocene age for the Tempanos moraines, Laguna San Rafael, Patagonian Chile
- 2012
-
Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 31, s. 82-92
-
Tidskriftsartikel (refereegranskat)abstract
- Data about the nature and timing of Holocene events from the Southern Hemisphere, especially in southern South America, are required to provide insight into the extent and nature of past climate change in a region where land-based records are restricted. Here we present the first use of single grain Optically Stimulated Luminescence (OSL) dating of a moraine sequence recording glacial advance along the western side of the Patagonian Icefields. Dates from the Tempanos moraines at Laguna San Rafael (LSR) show that the San Rafael Glacier (SRG) advanced to maximum Holocene positions during the period 9.3 to 9.7 ka and at 5.7 ka. Outwash lying beneath the moraine in its northern portion, dated to 7.7 ka, indicates that the glacier front was also advanced at this time. Since these advances span both the regional early Holocene warm-dry phase (11.5 ka to 7.8 ka) and the subsequent cooling and rise in precipitation in the mid-late Holocene (since 6.6 ka) we infer that the advances of the SRG are not simply climate-driven, but that the glacier has also probably responded strongly to non-climatic stimuli such as internal ice dynamics and the transition between calving and non-calving. Many westwards-flowing glaciers in Patagonia were probably calving during much of the Late Pleistocene and Holocene, so we conclude that establishing robust glacial chronologies where climatic and non-climatic factors cannot be distinguished is likely to remain a challenge.
|
|
