Bidifferential calculus, matrix SIT and sine-Gordon equations

We express a matrix version of the self-induced transparency (SIT) equations in the bidifferential calculus framework. An infinite family of exact solutions is then obtained by application of a general result that generates exact solutions from solutions of a linear system of arbitrary matrix size. A side result is a solution formula for the sine-Gordon equation.Comment: 7 pages, 2 figures, 19th International Colloquium on Integrable Systems and Quantum Symmetries (ISQS19), Prague, Czech Republic, June 201

Understanding the Why, What, and How of Theories in IS Research

Researchers have emphasized theory’s pivotal importance in the information systems (IS) discipline since its inception. As in many science disciplines, IS scholars’ ability to understand and contribute to theory is an important qualification in research practice. As a discipline, we require solid foundations for why we engage with theory, what theory is for us, and how we work with theory. We synthesize and reflect on the debates on theories and theorizing in the IS discipline. In doing so, we inform (particularly new) authors about the current state of the IS discipline’s debate on theory and theorizing and help them identify opportunities in theorizing to put theory to work. We do not intend to advocate or cement that status quo we portray but rather, through informing the community about it, to support early efforts to further develop and move beyond the current state of the debate on theory and theorizing in IS research

Endothelin-1 precursor peptides correlate with severity of disease and outcome in patients with community acquired pneumonia

<p>Abstract</p> <p>Background</p> <p>Circulating levels of endothelin-1 are increased in sepsis and correlate with severity of disease. A rapid and easy immunoassay has been developed to measure the more stable ET-1 precursor peptides proET-1. The objective of this study was to assess the diagnostic and prognostic value of proET-1 in a prospective cohort of mainly septic patients with community-acquired pneumonia.</p> <p>Methods</p> <p>We evaluated 281 consecutive patients with community acquired pneumonia. Serum proET-1 plasma levels were measured using a new sandwich immunoassay.</p> <p>Results</p> <p>ProET-1 levels exhibited a gradual increase depending on the clinical severity of pneumonia as assessed by the pneumonia severity index (PSI) and the CURB65 scores (p < 0.001 and p < 0.01). The diagnostic accuracy to predict bacteraemia of procalcitonin (AUC 0.84 [95% 0.74–0.93]) was superior than C-reactive protein (AUC 0.67 [95%CI 0.56–0.78]) and leukocyte count (AUC 0.66 [95%CI 0.55–0.78]) and in the range of proET-1(AUC of 0.77 [95%CI 0.67–0.86]). ProET-1 levels on admission were increased in patients with adverse medical outcomes including death and need for ICU admission. ROC curve analysis to predict the risk for mortality showed a prognostic accuracy of proET-1 (AUC 0.64 [95%CI 0.53–0.74]), which was higher than C-reactive protein (AUC 0.51 [95%CI 0.41–0.61]) and leukocyte count (AUC 0.55 [95%CI 0.44–0.65]) and within the range of the clinical severity scores (PSI AUC 0.69 [95%CI 0.61–0.76] and CURB65 0.67 [95%CI 0.57–0.77]) and procalcitonin (AUC 0.59 [95% 0.51–0.67]). ProET-1 determination improved significantly the prognostic accuracy of the CURB65 score (AUC of the combined model 0.69 [95%CI 0.59–0.79]). In a multivariate logistic regression model, only proET1 and the clinical severity scores were independent predictors for death and for the need for ICU admission.</p> <p>Conclusion</p> <p>In community-acquired pneumonia, ET-1 precursor peptides correlate with disease severity and are independent predictors for mortality and ICU admission. If confirmed in future studies, proET-1 levels may become another helpful tool for risk stratification and management of patients with community-acquired pneumonia.</p> <p>Trial registration</p> <p>ISRCTN04176397</p

Assessing the long‐term carbon‐sequestration potential of the semi‐natural salt marshes in the European Wadden Sea

Salt marshes and other blue carbon ecosystems have been increasingly recognized for their carbon (C)‐sink function. Yet, an improved assessment of organic carbon (OC) stocks and C‐sequestration rates is still required to include blue C in C‐crediting programs. Particularly, factors inducing variability in the permanence of sequestration and allochthonous contributions to soil OC stocks require an improved understanding. This study evaluates the potential for long‐term C sequestration in the semi‐natural salt marshes of the European Wadden Sea (WS), conducting deep (1.3 m) down‐core OC‐density assessments in sites with known site histories and accretion records. Because these young marshes have developed from tidal‐flat ecosystems and have undergone rapid succession during the last 80–120 yr, the identification of different ecosystem stages down‐core was crucial to interpret possible changes in OC density. This was conducted based on the down‐core distribution of different foraminiferal taxa and grain sizes. Comparisons of historic and recent accretion rates were conducted to understand possible effects of accretion rate on down‐core changes in OC density. δ13C in OC was used to assess the origin of accumulated OC (autochthonous vs. allochthonous sources). We show that large amounts of short‐term accumulated OC are lost down‐core in the well‐aerated marsh soils of the WS region and thus emphasize the importance of deep sampling to avoid overestimation of C sequestration. Despite steep declines in OC‐density down‐core, minimum values of OC density in the salt‐marsh soils were considerably higher than those of the former tidal‐flat sediments that the marshes were converted from, illustrating the greater C‐sequestration potential of the vegetated ecosystem. However, our data also suggest that marine‐derived allochthonous OC makes up a large fraction of the effectively, long‐term preserved OC stock, whereas atmospheric CO2 removal by marsh vegetation contributes relatively little. The implication of this finding for C‐crediting approaches in blue C ecosystems has yet to be clarified

Endovascular Therapy for Chronic Cerebrospinal Venous Insufficiency in Multiple Sclerosis

Recent reports have emerged suggesting that multiple sclerosis (MS) may be due to abnormal venous outflow from the central nervous system, termed chronic cerebrospinal venous insufficiency (CCSVI). These reports have generated strong interest and controversy over the prospect of a treatable cause of this chronic debilitating disease. This review aims to describe the proposed association between CCSVI and MS, summarize the current data, and discuss the role of endovascular therapy and the need for rigorous randomized clinical trials to evaluate this association and treatment

Adapting the randomised controlled trial (RCT) for precision medicine: introducing the nested-precision RCT (npRCT)

Adaptations to the gold standard randomised controlled trial (RCT) have been introduced to decrease trial costs and avoid high sample sizes. To facilitate development of precision medicine algorithms that aim to optimise treatment allocation for individual patients, we propose a new RCT adaptation termed the nested-precision RCT (npRCT). The npRCT combines a traditional RCT (intervention A versus B) with a precision RCT (stratified versus randomised allocation to A or B). This combination allows online development of a precision algorithm, thus providing an integrated platform for algorithm development and its testing. Moreover, as both the traditional and the precision RCT include participants randomised to interventions of interest, data from these participants can be jointly analysed to determine the comparative effectiveness of intervention A versus B, thus increasing statistical power. We quantify savings of the npRCT compared to two independent RCTs by highlighting sample size requirements for different target effect sizes and by introducing an open-source power calculation app. We describe important practical considerations such as blinding issues and potential biases that need to be considered when designing an npRCT. We also highlight limitations and research contexts that are less suited for an npRCT. In conclusion, we introduce the npRCT as a novel precision medicine trial design strategy which may provide one opportunity to efficiently combine traditional and precision RCTs

Etiology, 3-Month Functional Outcome and Recurrent Events in Non-Traumatic Intracerebral Hemorrhage

BACKGROUND AND PURPOSE Knowledge about different etiologies of non-traumatic intracerebral hemorrhage (ICH) and their outcomes is scarce. METHODS We assessed prevalence of pre-specified ICH etiologies and their association with outcomes in consecutive ICH patients enrolled in the prospective Swiss Stroke Registry (2014 to 2019). RESULTS We included 2,650 patients (mean±standard deviation age 72±14 years, 46.5% female, median National Institutes of Health Stroke Scale 8 [interquartile range, 3 to 15]). Etiology was as follows: hypertension, 1,238 (46.7%); unknown, 566 (21.4%); antithrombotic therapy, 227 (8.6%); cerebral amyloid angiopathy (CAA), 217 (8.2%); macrovascular cause, 128 (4.8%); other determined etiology, 274 patients (10.3%). At 3 months, 880 patients (33.2%) were functionally independent and 664 had died (25.1%). ICH due to hypertension had a higher odds of functional independence (adjusted odds ratio [aOR], 1.33; 95% confidence interval [CI], 1.00 to 1.77; P=0.05) and lower mortality (aOR, 0.64; 95% CI, 0.47 to 0.86; P=0.003). ICH due to antithrombotic therapy had higher mortality (aOR, 1.62; 95% CI, 1.01 to 2.61; P=0.045). Within 3 months, 4.2% of patients had cerebrovascular events. The rate of ischemic stroke was higher than that of recurrent ICH in all etiologies but CAA and unknown etiology. CAA had high odds of recurrent ICH (aOR, 3.38; 95% CI, 1.48 to 7.69; P=0.004) while the odds was lower in ICH due to hypertension (aOR, 0.42; 95% CI, 0.19 to 0.93; P=0.031). CONCLUSIONS Although hypertension is the leading etiology of ICH, other etiologies are frequent. One-third of ICH patients are functionally independent at 3 months. Except for patients with presumed CAA, the risk of ischemic stroke within 3 months of ICH was higher than the risk of recurrent hemorrhage

Importance of Orbital Spectroscopy on Venus

Using five band orbital emissivity measurements in the 1 micron region has tremendous potential to provide global maps of Venus surface rock types. Combining this with 480°C laboratory measurement will poise Venus science for a dramatic improvement in understanding of surface geology and the formation and internal processes of Earth’s twin planet