Increases in Future AR Count and Size: Overview of the ARTMIP Tier 2 CMIP5/6 Experiment.

The Atmospheric River (AR) Tracking Method Intercomparison Project (ARTMIP) is a community effort to systematically assess how the uncertainties from AR detectors (ARDTs) impact our scientific understanding of ARs. This study describes the ARTMIP Tier 2 experimental design and initial results using the Coupled Model Intercomparison Project (CMIP) Phases 5 and 6 multi-model ensembles. We show that AR statistics from a given ARDT in CMIP5/6 historical simulations compare remarkably well with the MERRA-2 reanalysis. In CMIP5/6 future simulations, most ARDTs project a global increase in AR frequency, counts, and sizes, especially along the western coastlines of the Pacific and Atlantic oceans. We find that the choice of ARDT is the dominant contributor to the uncertainty in projected AR frequency when compared with model choice. These results imply that new projects investigating future changes in ARs should explicitly consider ARDT uncertainty as a core part of the experimental design.

Etiology of first-ever ischaemic stroke in European young adults: the 15 cities young stroke study.

BACKGROUND AND PURPOSE: Risk factors for IS in young adults differ between genders and evolve with age, but data on the age- and gender-specific differences by stroke etiology are scare. These features were compared based on individual patient data from 15 European stroke centers. METHODS: Stroke etiology was reported in detail for 3331 patients aged 15-49 years with first-ever IS according to Trial of Org in Acute Stroke Treatment (TOAST) criteria: large-artery atherosclerosis (LAA), cardioembolism (CE), small-vessel occlusion (SVO), other determined etiology, or undetermined etiology. CE was categorized into low- and high-risk sources. Other determined group was divided into dissection and other non-dissection causes. Comparisons were done using logistic regression, adjusting for age, gender, and center heterogeneity. RESULTS: Etiology remained undetermined in 39.6%. Other determined etiology was found in 21.6%, CE in 17.3%, SVO in 12.2%, and LAA in 9.3%. Other determined etiology was more common in females and younger patients, with cervical artery dissection being the single most common etiology (12.8%). CE was more common in younger patients. Within CE, the most frequent high-risk sources were atrial fibrillation/flutter (15.1%) and cardiomyopathy (11.5%). LAA, high-risk sources of CE, and SVO were more common in males. LAA and SVO showed an increasing frequency with age. No significant etiologic distribution differences were found amongst southern, central, or northern Europe. CONCLUSIONS: The etiology of IS in young adults has clear gender-specific patterns that change with age. A notable portion of these patients remains without an evident stroke mechanism according to TOAST criteria.

Isolated monoparesis following stroke.

BACKGROUND: Some investigators have stated that monoparesis is almost never the result of a lacunar infarct or cerebral haemorrhage. OBJECTIVE: To describe the topography and aetiology in a consecutive population where first ever stroke was manifested by isolated monoparesis. METHODS: Patients with motor paresis of only one limb were included consecutively in the study. A neuroradiologist determined stroke location, while a neurologist reviewed the clinical records to assign stroke subtype. Both physicians worked blind to each other's findings. RESULTS: 51 of 2003 patients (2.5%) had isolated monoparesis, and of these 39 (76.5%) were ischaemic strokes and 12 (23.5%) were haemorrhagic. Cardioembolism was the cause of stroke in 15.7%, atherosclerosis in 9.8%, and small artery disease in 39.2%. Most of the haemorrhages were in the thalamic-capsular region (5/12). Most of the ischaemic lesions were in the deep territory of the middle cerebral artery, the corona radiate, or the centrum semiovale (20/39); 16 of 39 were in the cortical territories or the watershed region. CONCLUSIONS: Isolated monoparesis is a rare symptom in stroke patients and is often caused by small artery disease or a small haemorrhage.