X509CLOUD - FRAMEWORK FOR A UBIQUITOUS PKI

The SSL protocol has been widely used for verifying digital identities and to secure Internet traffic since the early days of the web. Although X.509 certificates have been in existence for more than two decades, individual user uptake has been low due to the high cost of issuance and maintenance of such certs. This has led to a situation whereby users are able to verify the identity of an organization or e-commerce retailer via their digital certificate, but organizations have to rely on weak username and password combinations to verify the identity of customers registered with their service. We propose the X509Cloud framework which enables organizations to issue certificates to their users at zero cost, and allows them to securely store and disseminate client certificates using the Bitcoin inspired blockchain protocol. This in turn will enable organizations and individuals to authenticate and to securely communicate with other users on the Internet

A shock recovery experiment and its implications for Mercury's surface : The effect of high pressure on porous olivine powder as a regolith analog

We conducted classic dynamic high - pressure experiments on porous San Carlos (SC) olivine powder to examine if and how different shock stages modify corresponding reflectance mid – infrared (MIR) spectra. Microscopic investigation of the thin sections produced of our shocked samples indicates local peak pressures of >60 GPa along with all lower grade shock stages. Spectral analyses of optically identified shock areas were documented and compared in terms of Christiansen Feature (CF) and the position of olivine – diagnostic Reststrahlenbands (RBs). We found that one RB (fundamental vibrations of the orthosilicate - ion) of olivine occurring at 980 cm−1 (corresponding to ≈ 10.2 μm) shows the least energetic shift in the investigated MIR spectra and could therefore serve as a proxy for the presence of olivine in remote sensing application. Furthermore, a peak located at ≈ 1060 cm−1 (≈ 9.4 μm) shows a significant intensity change probably related to the degree of shock exposure or grain orientation effects, as we observe a decline in intensity of this band from our averaged reference olivine spectra of our IRIS database (diffuse reflectance measurement) down to spectra of grains showing mosaicism and recrystallized areas. We also report the presence of a weak band in some of the olivine spectra located at ≈ 1100 cm−1 (9.1 μm) that has an influence on the position of the CF when spectral data of olivine are averaged.Peer reviewe

Flattening the curve in 52 days: characterisation of the COVID-19 pandemic in the Principality of Liechtenstein - an observational study.

BACKGROUND The principality of Liechtenstein had its first COVID-19 case at the beginning of March 2020. After exponential growth, the pandemic’s first wave was contained, with the last case being diagnosed 52 days after the initial occurrence. AIM To characterise the COVID-19 pandemic in Liechtenstein. METHODS All patients diagnosed in Liechtenstein were followed up until recovery and again 6–8 weeks after symptom onset. They were contacted every 2 days to record their clinical status until the resolution of their symptoms. The diagnosis of COVID-19 was based on clinical symptoms and molecular testing. Household and close workplace contacts were included in the follow-up, which also comprised antibody testing. In addition, public health measures installed during the pandemic in Liechtenstein are summarised. RESULTS During the first wave, 5% of the population obtained a reverse transcriptase polymerase chain reaction test. A total of 95 patients (median age 39 years) were diagnosed with COVID-19 (82 who resided in Liechtenstein), resulting in an incidence in Liechtenstein of 0.211%. One patient, aged 94, died (mortality rate 1%). Only 62% of patients could retrospectively identify a potential source of infection. Testing the patients’ household and close workplace contacts (n = 170) with antibody tests revealed that 25% of those tested were additional COVID-19 cases, a quarter of whom were asymptomatic. Those households which adhered to strict isolation measures had a significantly lower rate of affected household members than those who didn’t follow such measures. The national public health measures never restricted free movement of residents. Masks were only mandatory in healthcare settings. The use of home working for the general workforce was promoted. Gatherings were prohibited. Schools, universities, certain public spaces (like sports facilities and playgrounds), childcare facilities, nonessential shops, restaurants and bars were closed. Social distancing, hygienic measures, solidarity and supporting individuals who were at risk were the main pillars of the public health campaigns. CONCLUSION The close collaboration of all relevant stakeholders allowed for the complete workup of all COVID-19 patients nationwide. A multitude of factors (e.g., young age of the patients, low-threshold access to testing, close monitoring of cases, high alertness and adherence to public health measures by the population) led to the early containment of the first wave of the pandemic, with a very low rate of serious outcomes. Antibody testing for SARS-CoV-2 revealed a substantial proportion of undiagnosed COVID-19 cases among close contacts of the patients

Compositional variability in a cold-water scleractinian, Lophelia pertusa : new insights into “vital effects”

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 7 (2006): Q12004, doi:10.1029/2006GC001354.We analyzed Sr/Ca and Mg/Ca ratios in the thecal wall of Lophelia pertusa, a cold-water coral, using SIMS ion microprobe techniques. The wall grows by simultaneous upward extension and outward thickening. Compositional variability displays similar trends along the upward and outward growth axes. Sr/Ca and Mg/Ca ratios oscillate systematically and inversely. The sensitivity of Lophelia Sr/Ca ratios to the annual temperature cycle (−0.18 mmol · mol−1/°C) is twice as strong as that exhibited by tropical reef corals, and four times as strong as the temperature dependence of Sr/Ca ratios of abiogenic aragonites precipitated experimentally from seawater. A comparison of the skeletal composition of Lophelia with results from precipitation calculations carried out using experimentally determined partition coefficients suggests that both temperature-dependent element partitioning and seasonal changes in the mass fraction of aragonite precipitated from the calcifying fluid influence the composition of Lophelia skeleton. Results from calculations that combine these effects reproduce both the exaggerated amplitude of the Sr/Ca and Mg/Ca oscillations and the inverse relationship between Sr/Ca and Mg/Ca ratios.This study was supported in part by a WHOI Ocean Life Institute fellowship to ALC, by NSF grant OCE-0527350 to G.A.G. and A.L.C., and by the EU 6FP project HERMES, EC contract GOCE-CT-2005-511234 to T.L

Long‐Term Outcome and Quality of Life in Patients With Stroke Presenting With Extensive Early Infarction

Background The benefit of mechanical thrombectomy in patients with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) for short‐term outcomes is debatable and long‐term outcomes remain unknown. This retrospective, monocentric cohort study aimed to assess the association between reperfusion grade and the long‐term functional outcome measured with modified Rankin scale as well as the long‐term health‐related quality of life recorded at the last follow‐up in patients according to baseline ASPECTS (0–5 versus 6–10). Methods Deceased patients were identified from the Swiss population register and follow‐up telephone interviews were conducted with all surviving patients with stroke treated with mechanical thrombectomy between January 1, 2010, and December 31, 2018. Favorable outcome was defined as modified Rankin scale 0 to 3; health‐related quality of life was assessed using the 3‐level version of the EuroQol 5‐dimensional questionnaire. The EuroQol 5‐dimension utility index was calculated for statistical analyses. The reperfusion grade was core laboratory adjudicated using the expanded treatment in cerebral ischemia score. Adjusted odds ratios for the association between the reperfusion grade assessed by expanded treatment in cerebral ischemia and outcomes were calculated from multivariable logistic regression. Results Of the 1114 patients with available long‐term follow‐up records (median follow‐up, 3.67 years), 997 were included in the final analysis. Respectively, patients with low ASPECTS more often had complaints regarding mobility (67.1% versus 42.1%, P<0.001), self‐care (53.4% versus 31.2%, P<0.001), and usual activities (65.8% versus 41.4%, P<0.001) than patients with high ASPECTS, whereas reported pain/discomfort (65.7% versus 69.9%, P=0.49) and anxiety/depression (71.2% versus 78.9%, P=0.17) did not differ. In patients with low ASPECTS, increasing reperfusion grade was associated with a higher likelihood of long‐term favorable functional outcome (adjusted odds ratio, 1.43; 95% CI, 1.09–1.88 [P=0.01]) and health‐related quality of life (adjusted linear correlation coefficient, 0.05; 95% CI, 0.02–0.08) despite early extensive infarction. Conclusion Despite low baseline ASPECTS, a higher reperfusion grade results in better functional outcomes and may improve health‐related quality of life in the long term

Long-Term Effect of Mechanical Thrombectomy in Stroke Patients According to Advanced Imaging Characteristics.

PURPOSE Data on long-term effect of mechanical thrombectomy (MT) in patients with large ischemic cores (≥ 70 ml) are scarce. Our study aimed to assess the long-term outcomes in MT-patients according to baseline advanced imaging parameters. METHODS We performed a single-centre retrospective cohort study of stroke patients receiving MT between January 1, 2010 and December 31, 2018. We assessed baseline imaging to determine core and mismatch volumes and hypoperfusion intensity ratio (with low ratio reflecting good collateral status) using RAPID automated post-processing software. Main outcomes were cross-sectional long-term mortality, functional outcome and quality of life by May 2020. Analysis were stratified by the final reperfusion status. RESULTS In total 519 patients were included of whom 288 (55.5%) have deceased at follow-up (median follow-up time 28 months, interquartile range 1-55). Successful reperfusion was associated with lower long-term mortality in patients with ischemic core volumes ≥ 70 ml (adjusted hazard ratio (aHR) 0.20; 95% confidence interval (95% CI) 0.10-0.44) and ≥ 100 ml (aHR 0.26; 95% CI 0.08-0.87). The effect of successful reperfusion on long-term mortality was significant only in the presence of relevant mismatch (aHR 0.17; 95% CI 0.01-0.44). Increasing reperfusion grade was associated with a higher rate of favorable outcomes (mRS 0-3) also in patients with ischemic core volume ≥ 70 ml (aOR 3.58, 95% CI 1.64-7.83). CONCLUSION Our study demonstrated a sustainable benefit of better reperfusion status in patients with large ischemic core volumes. Our results suggest that patient deselection based on large ischemic cores alone is not advisable

Comparison of the chemical evolution and characteristics of 495 biomass burning plumes intercepted by the NASA DC-8 aircraft during the ARCTAS/CARB-2008 field campaign

This paper compares measurements of gaseous and particulate emissions from a wide range of biomass-burning plumes intercepted by the NASA DC-8 research aircraft during the three phases of the ARCTAS-2008 experiment: ARCTAS-A, based out of Fairbanks, Alaska USA (3 April to 19 April 2008); ARCTAS-B based out of Cold Lake, Alberta, Canada (29 June to 13 July 2008); and ARCTAS-CARB, based out of Palmdale, California, USA (18 June to 24 June 2008). Extensive investigations of boreal fire plume evolution were undertaken during ARCTAS-B, where four distinct fire plumes that were intercepted by the aircraft over a range of down-wind distances (0.1 to 16 hr transport times) were studied in detail. Based on these analyses, there was no evidence for ozone production and a box model simulation of the data confirmed that net ozone production was slow (on average 1 ppbv h−1 in the first 3 h and much lower afterwards) due to limited NOx. Peroxyacetyl nitrate concentrations (PAN) increased with plume age and the box model estimated an average production rate of ~80 pptv h−1 in the first 3 h. Like ozone, there was also no evidence for net secondary inorganic or organic aerosol formation. There was no apparent increase in aerosol mass concentrations in the boreal fire plumes due to secondary organic aerosol (SOA) formation; however, there were indications of chemical processing of the organic aerosols. In addition to the detailed studies of boreal fire plume evolution, about 500 smoke plumes intercepted by the NASA DC-8 aircraft were segregated by fire source region. The normalized excess mixing ratios (i.e. ΔX/ΔCO) of gaseous (carbon dioxide, acetonitrile, hydrogen cyanide, toluene, benzene, methane, oxides of nitrogen (NOx), ozone, PAN) and fine aerosol particulate components (nitrate, sulfate, ammonium, chloride, organic aerosols and water soluble organic carbon) of these plumes were compared