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- Brehm, Nicolas, et al.
(författare)
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Tree-rings reveal two strong solar proton events in 7176 and 5259 BCE
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- The Sun sporadically produces eruptive events leading to intense fluxes of solar energetic particles (SEPs) that dramatically disrupt the near-Earth radiation environment. Such events have been directly studied for the last decades but little is known about the occurrence and magnitude of rare, extreme SEP events. Presently, a few events that produced measurable signals in cosmogenic radionuclides such as 14C, 10Be and 36Cl have been found. Analyzing annual 14C concentrations in tree-rings from Switzerland, Germany, Ireland, Russia, and the USA we discovered two spikes in atmospheric 14C occurring in 7176 and 5259 BCE. The ~2% increases of atmospheric 14C recorded for both events exceed all previously known 14C peaks but after correction for the geomagnetic field, they are comparable to the largest event of this type discovered so far at 775 CE. These strong events serve as accurate time markers for the synchronization with floating tree-ring and ice core records and provide critical information on the previous occurrence of extreme solar events which may threaten modern infrastructure.
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| 2. |
- Psychogios, Marios, et al.
(författare)
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European Stroke Organisation guidelines on treatment of patients with intracranial atherosclerotic disease
- 2022
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Ingår i: European Stroke Journal. - : SAGE Publications. - 2396-9881 .- 2396-9873.
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present European Stroke Organisation guideline is to provide clinically useful evidence-basedrecommendations on the management of patients with intracranial atherosclerotic disease (ICAD). The guidelines wereprepared following the Standard Operational Procedure of the European Stroke Organisation guidelines and accordingto GRADE methodology. ICAD represents a major cause of ischemic stroke worldwide, and patients affected by thiscondition are exposed to a high risk for future strokes and other major cardiovascular events, despite best medicaltherapy available. We identified 11 relevant clinical problems affecting ICAD patients and formulated the correspondingPopulation Intervention Comparator Outcomes (PICO) questions. The first two questions refer to the asymptomaticstage of the disease, which is being increasingly detected thanks to the routine use of noninvasive vascular imaging. Wewere not able to provide evidence-based recommendations regarding the optimal detection strategy and management ofasymptomatic ICAD, and further research in the field is encouraged as subclinical ICAD may represent a big opportunityto improve primary stroke prevention. The second block of PICOs (3–5) is dedicated to the management of acutelarge vessel occlusion (LVO) ischemic stroke caused by ICAD, a clinical presentation of this disease that is becomingincreasingly relevant and problematic, since it is associated with more refractory endovascular reperfusion procedures.An operational definition of probable ICAD-related LVO is proposed in the guideline. Despite the challenging context,no dedicated randomized clinical trials (RCTs) were identified, and therefore the guideline can only provide withsuggestions derived from observational studies and our expert consensus, such as the escalated use of glycoproteinIIb-IIIa inhibitors and angioplasty/stenting in cases of refractory thrombectomies due to underlying ICAD. The last blockof PICOs is devoted to the secondary prevention of patients with symptomatic ICAD. Moderate-level evidence wasfound to recommend against the use of oral anticoagulation as preferred antithrombotic drug, in favor of antiplatelets.Low-level evidence based our recommendation in favor of double antiplatelet as the antithrombotic treatment of choicein symptomatic ICAD patients, which we suggest to maintain during 90days as per our expert consensus. Endovasculartherapy with intracranial angioplasty and or stenting is not recommended as a treatment of first choice in high-gradesymptomatic ICAD (moderate-level evidence). Regarding neurosurgical interventions, the available evidence does notsupport their use as front line therapies in patients with high-grade ICAD. There is not enough evidence as to provideany specific recommendation regarding the use of remote ischemic conditioning in ICAD patients, and further RCTsare needed to shed light on the utility of this promising therapy. Finally, we dedicate the last PICO to the importanceof aggressive vascular risk factor management in ICAD, although the evidence derived from RCTs specifically addressingthis question is still scarce
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