7 research outputs found
The hydro-geomorphological setting of the Old Kingdom town of al-Ashmūnayn in the Egyptian Nile Valley
The ancient Egyptian city of al-Ashmūnayn (Minyā Governorate, Egypt) has been an important regional centre since at least the Old Kingdom (c. 2686–2160 BC). It is assumed to have been founded on the banks of the Nile, although no scientific evidence was hitherto available to support this claim. In this multidisciplinary study, the results of a geoarchaeological survey were combined with the study of pottery fragments. Boreholes placed at al-Ashmūnayn produced thick layers of late Old Kingdom pottery in association with the local occurrence of river channel deposits, allowing us to conclude that it is very likely that al-Ashmūnayn originated on the banks of the Nile River. The regional borehole survey demonstrates that major geomorphological reconfigurations of the fluvial landscape occurred throughout the late Holocene, notably by the process of river avulsion. An interconnectedness of changes in the natural Nile Valley landscape and cultural dynamics of the ancient Egyptian riverine society seems possible, based on the coincidence of river reconfigurations with shifts in the preferential locations for high-status burials in the region
Recent advances in paleoflood hydrology: From new archives to data compilation and analysis
8 pags, 4 figsAssessments of present and future flood hazard are often limited by the scarcity and short time span of the instrumental time series. In pursuit of documenting the occurrence and magnitude of pre-instrumental flood events, the field of paleoflood hydrology emerged during the second half of the 20th century. Historically, this field has mainly been developed on the identification and dating of flood evidence in fluvial sedimentary archives. In the last two decades, paleoflood hydrology approaches have also been deployed to investigate past floods contained in other natural archives. This article reviews major methodological and technological advancements in the study of lake sediments with the aim to showcase new, robust and continuous paleoflood series. Methodological advancements of flood archives such as tree rings and speleothems are also addressed. The recent developments in these fields have resulted in a growing paleoflood community that opens for cross-disciplinary analysis and synthesis of large data sets to meet the pressing scientific challenges in understanding changes in flood frequency and magnitude
Challenges in the attribution of river flood events
Advances in the field of extreme event attribution allow to estimate how anthropogenic global warming affects the odds of individual climate disasters, such as river floods. Extreme event attribution typically uses precipitation as proxy for flooding. However, hydrological processes and antecedent conditions make the relation between precipitation and floods highly nonlinear. In addition, hydrology acknowledges that changes in floods can be strongly driven by changes in land-cover and by other human interventions in the hydrological system, such as irrigation and construction of dams. These drivers can either amplify, dampen or outweigh the effect of climate change on local flood occurrence. Neglecting these processes and drivers can lead to incorrect flood attribution. Including flooding explicitly, that is, using data and models of hydrology and hydrodynamics that can represent the relevant hydrological processes, will lead to more robust event attribution, and will account for the role of other drivers beyond climate change. Existing attempts are incomplete. We argue that the existing probabilistic framework for extreme event attribution can be extended to explicitly include floods for near-natural cases, where flood occurrence was unlikely to be influenced by land-cover change and human hydrological interventions. However, for the many cases where this assumption is not valid, a multi-driver framework for conditional event attribution needs to be established. Explicit flood attribution will have to grapple with uncertainties from lack of observations and compounding from the many processes involved. Further, it requires collaboration between climatologists and hydrologists, and promises to better address the needs of flood risk management. This article is categorized under: Paleoclimates and Current Trends > Modern Climate Change Paleoclimates and Current Trends > Detection and Attribution Assessing Impacts of Climate Change > Observed Impacts of Climate Change.</p
Shift away from Nile incision at Luxor ~4000 years ago impacted ancient Egyptian landscapes
Although the Nile is one of the largest rivers in the world and played a central role in ancient Egyptian life, little is known about its response to climatic change during the Holocene. Here we present a framework for the evolution of the Egyptian Nile, demonstrating how climatic and environmental changes have shaped the landscape of the Egyptian Nile Valley over the past 11,500 years, including the civilization of ancient Egypt (~5,000 to 2,000 years ago). Using data from over 80 sediment cores drilled in a transect spanning the Nile Valley near Luxor, pinned in time by 48 optically stimulated luminescence ages, we reconstruct the dynamics of the Nile River during the Holocene in the vicinity of UNESCO World Heritage sites such as Karnak and Luxor temples. According to our reconstruction, valley incision occurred from the start of the record until approximately 4,000 years ago and then rapidly shifted to massive floodplain aggradation. We argue that this relatively abrupt change in the riverine landscape near Luxor from the Middle to Late Holocene was linked to a shift towards a drier regional hydroclimate around this time. Such a dramatic change in river sediment dynamics could have had local agro-economic consequences
Common and different genetic background for rheumatoid arthritis and coeliac disease
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81471.pdf (publisher's version ) (Closed access)Recent genome-wide association studies (GWAS) have revealed genetic risk factors in autoimmune and inflammatory disorders. Several of the associated genes and underlying pathways are shared by various autoimmune diseases. Rheumatoid arthritis (RA) and coeliac disease (CD) are two autoimmune disorders which have commonalities in their pathogenesis. We aimed to replicate known RA loci in a Dutch RA population, and to investigate whether the effect of known RA and CD risk factors generalize across the two diseases. We selected all loci associated to either RA or CD in a GWAS and confirmed in an independent cohort, with a combined P-value cut-off P < 5 x 10(-6). We genotyped 11 RA and 11 CD loci in 1368 RA patients, 795 CD patients and 1683 Dutch controls. We combined our results in a meta-analysis with UK GWAS on RA (1860 cases; 2938 controls) and CD (767 cases; 1422 controls). In the Dutch RA cohort, the PTPN22 and IL2/IL21 variants showed convincing association (P = 3.4 x 10(-12) and P = 2.8 x 10(-4), respectively). Association of RA with the known CD risk variant in the SH2B3 was also observed, predominantly in the subgroup of rheumatoid factor-positive RA patients (P = 0.0055). In a meta-analysis of Dutch and UK data sets, shared association with six loci (TNFAIP3, IL2/IL21, SH2B3, LPP, MMEL1/TNFRSF14 and PFKFB3/PRKCQ) was observed in both RA and CD cohorts. We confirmed two known loci and identified four novel ones for shared CD-RA genetic risk. Most of the shared loci further emphasize a role for adaptive and innate immunity in these diseases
High treatment uptake in human immunodeficiency virus/ hepatitis C virus-coinfected patients after unrestricted access to direct-acting antivirals in the Netherlands
Background
The Netherlands has provided unrestricted access to direct-acting antivirals (DAAs) since November 2015. We analyzed the nationwide hepatitis C virus (HCV) treatment uptake among patients coinfected with human immunodeficiency virus (HIV) and HCV.
Methods
Data were obtained from the ATHENA HIV observational cohort in which >98% of HIV-infected patients ever registered since 1998 are included. Patients were included if they ever had 1 positive HCV RNA result, did not have spontaneous clearance, and were known to still be in care. Treatment uptake and outcome were assessed. When patients were treated more than once, data were included from only the most recent treatment episode. Data were updated until February 2017. In addition, each treatment center was queried in April 2017 for a data update on DAA treatment and achieved sustained virological response.
Results
Of 23574 HIV-infected patients ever linked to care, 1471 HCV-coinfected patients (69% men who have sex with men, 15% persons who [formerly] injected drugs, and 15% with another HIV transmission route) fulfilled the inclusion criteria. Of these, 87% (1284 of 1471) had ever initiated HCV treatment between 2000 and 2017, 76% (1124 of 1471) had their HCV infection cured; DAA treatment results were pending in 6% (92 of 1471). Among men who have sex with men, 83% (844 of 1022) had their HCV infection cured, and DAA treatment results were pending in 6% (66 of 1022). Overall, 187 patients had never initiated treatment, DAAs had failed in 14, and a pegylated interferon-alfa–based regimen had failed in 54.
Conclusions
Fifteen months after unrestricted DAA availability the majority of HIV/HCV-coinfected patients in the Netherlands have their HCV infection cured (76%) or are awaiting DAA treatment results (6%). This rapid treatment scale-up may contribute to future HCV elimination among these patients