376 research outputs found

    Optimal options for rendezvous and impact missions to NEOs

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    In this paper some potentially interesting transfer options for missions to Near Earth Objects have been studied. Due to thehigh number of potential targets and to the large variety of possible missions that can be considered, especially if resorting to low-thrust propulsion, an extensive analysis of transfer options requires a preliminary approach oriented toward an effective global search, and an appropriately simplified trajectory transcription. Low-thrust options have been modeled through a novel shape-based approach and a global optimization method has been used to look for globally optimal transfers. Different targets have been identified and various mission scenarios have been considered: rendezvous, sample return missions both with and without Earth gravity assist and impact missions

    Big Pimpin’. Een big data-benadering van de verspreiding van het leenwoord pimpen in het Nederlands

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    peer reviewedThis article illustrates some of the opportunities and challenges of pursuing a big data approach in linguistic research. To do so, we investigate the diffusion of the loan verb pimpen ‘to fancify’ in Dutch based on Twitter data. First, we focus on the derivations of the verb (e.g.: terugpimpen ‘to pimp back’, herpimpen ‘to repimp’, etc.) and plot the diversity of these forms through time, using the Chao-Wang-Jost estimation of Shannon entropy. We follow this up with an alternation study that compares pimpen not only to its ‘native’ alternative opleuken, but also its most frequent derivation oppimpen, using multinomial regression. It is found that, while pimpen’s early expansion in Dutch has proceeded at breakneck speed, resulting e.g. in a plethora of derivations that has so far gone undetected, its current momentum seems to be waning

    Direct 16S rRNA-seq from bacterial communities: a PCR-independent approach to simultaneously assess microbial diversity and functional activity potential of each taxon

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    The analysis of environmental microbial communities has largely relied on a PCR-dependent amplification of genes entailing species identity as 16S rRNA. This approach is susceptible to biases depending on the level of primer matching in different species. Moreover, possible yet-to-discover taxa whose rRNA could differ enough from known ones would not be revealed. DNA-based methods moreover do not provide information on the actual physiological relevance of each taxon within an environment and are affected by the variable number of rRNA operons in different genomes. To overcome these drawbacks we propose an approach of direct sequencing of 16S ribosomal RNA without any primer- or PCR-dependent step. The method was tested on a microbial community developing in an anammox bioreactor sampled at different time-points. A conventional PCR-based amplicon pyrosequencing was run in parallel. The community resulting from direct rRNA sequencing was highly consistent with the known biochemical processes operative in the reactor. As direct rRNA-seq is based not only on taxon abundance but also on physiological activity, no comparison between its results and those from PCR-based approaches can be applied. The novel principle is in this respect proposed not as an alternative but rather as a complementary methodology in microbial community studies

    First-Response ABCDE Management of Status Epilepticus: A Prospective High-Fidelity Simulation Study

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    Respiratory infections following status epilepticus (SE) are frequent, and associated with higher mortality, prolonged ICU stay, and higher rates of refractory SE. Lack of airway protection may contribute to respiratory infectious complications. This study investigates the order and frequency of physicians treating a simulated SE following a systematic Airways-Breathing-Circulation-Disability-Exposure (ABCDE) approach, identifies risk factors for non-adherence, and analyzes the compliance of an ABCDE guided approach to SE with current guidelines. We conducted a prospective single-blinded high-fidelity trial at a Swiss academic simulator training center. Physicians of different affiliations were confronted with a simulated SE. Physicians (; n; = 74) recognized SE and performed a median of four of the five ABCDE checks (interquartile range 3-4). Thereof, 5% performed a complete assessment. Airways were checked within the recommended timeframe in 46%, breathing in 66%, circulation in 92%, and disability in 96%. Head-to-toe (exposure) examination was performed in 15%. Airways were protected in a timely manner in 14%, oxygen supplied in 69%, and antiseizure drugs (ASDs) administered in 99%. Participants' neurologic affiliation was associated with performance of fewer checks (regression coefficient -0.49;; p; = 0.015). We conclude that adherence to the ABCDE approach in a simulated SE was infrequent, but, if followed, resulted in adherence to treatment steps and more frequent protection of airways

    Renal function impairment predicts mortality in patients with chronic heart failure treated with resynchronization therapy

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    Background: The use of cardiac resynchronization therapy (CRT) and implantable cardioverter- defibrillator (ICD) for advanced heart failure (HF) is increasing. Renal dysfunction is a common condition in HF which is associated with a worse survival. The study aims at identifying in patients with advanced HF treated with CRT the effect of baseline glomerular filtration rate (GFR), GFR improvement and left ventricular ejection fraction (LVEF) change, after 6-months of CRT implant, on survival. Methods: The study population consisted of 375 advanced HF patients who received a CRT between 1999 and 2009, of these 277 received also an ICD implant. Clinical characteristics (New York Heart Association [NYHA] functional class, ischemic vs. non-ischemic etiology, atrial fibrillation, diabetes, hypertension, LVEF, QRS duration and GFR were recorded. The use of common used drugs was evaluated. Cox proportional hazards analysis was calculated in order to evaluate variables associated to mortality. Results: During a median follow-up of 43.0 months, 93 (24.8%) patients died. Patients deceased during the study had at baseline higher NYHA class and lower LVEF and GFR. In Cox regression analysis, GFR predicts long-term mortality (hazard ratio [HR] 0.983; 95% confidence interval [CI] 0.969–0.998; p = 0.023) independently from the effect of others covariates. In addition, a positive GFR improvement 6 months after CRT implant is significantly associated with a lower hazard of mortality (for each 10 mL/min of GFR improvement HR 0.86; 95% CI 0.75–0.99; p = 0.038). Conclusions: GFR is a significant predictor of mortality in advanced HF patients who received CRT. A GFR improvement 6 months after CRT implant is significantly associated with a lower hazard of mortality.
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