346 research outputs found

    Political ambition and opposition legislative review: Bill scrutiny as an intra-party signalling device

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    Recent research on executive–legislative relations in parliamentary democracies has shown that members of majority parties submit amendments to government bills to police the coalition compromise and to distinguish themselves from their coalition partners. It is poorly understood, however, what motivates members of the opposition to engage in the resource-intensive work of proposing changes to government bills. Not only are amendment proposals by the opposition often unsuccessful (lack of policy motivation), they are largely invisible to the electorate (lack of vote motivation). We argue that amendments by the opposition are best understood as reflecting office motivations of legislators. Ambitious legislators draft amendments to signal skill and expertise to their party peers, which is rewarded with promotions to higher office. We confirm our argument with original data from a German state parliament. The findings further our understanding of legislative review, individual legislative efforts and career trajectories

    Osmosis : a molecular dynamics computer simulation study

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    Osmosis is a phenomenon of critical importance in a variety of processes ranging from the transport of ions across cell membranes and the regulation of blood salt levels by the kidneys to the desalination of water and the production of clean energy using potential osmotic power plants. However, despite its importance and over one hundred years of study, there is an ongoing confusion concerning the nature of the microscopic dynamics of the solvent particles in their transfer across the membrane. In this thesis the microscopic dynamical processes underlying osmotic pressure and concentration gradients are investigated using molecular dynamics (MD) simulations. I first present a new derivation for the local pressure that can be used for determining osmotic pressure gradients. Using this result, the steady-state osmotic pressure is studied in a minimal model for an osmotic system and the steady-state density gradients are explained using a simple mechanistic hopping model for the solvent particles. The simulation setup is then modified, allowing us to explore the timescales involved in the relaxation dynamics of the system in the period preceding the steady state. Further consideration is also given to the relative roles of diffusive and non-diffusive solvent transport in this period. Finally, in a novel modi cation to the classic osmosis experiment, the solute particles are driven out-of-equilibrium by the input of energy. The effect of this modi cation on the osmotic pressure and the osmotic ow is studied and we find that active solute particles can cause reverse osmosis to occur. The possibility of defining a new "osmotic effective temperature" is also considered and compared to the results of diffusive and kinetic temperatures

    Computing the local pressure in molecular dynamics simulations

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    Computer simulations of inhomogeneous soft matter systems often require accurate methods for computing the local pressure. We present a simple derivation, based on the virial relation, of two equivalent expressions for the local (atomistic) pressure in a molecular dynamics simulation. One of these expressions, previously derived by other authors via a different route, involves summation over interactions between particles within the region of interest; the other involves summation over interactions across the boundary of the region of interest. We illustrate our derivation using simulations of a simple osmotic system; both expressions produce accurate results even when the region of interest over which the pressure is measured is very small.Comment: 11 pages, 4 figure

    Diagnostic Parameters of Adenoviremia in Pediatric Stem Cell Transplant Recipients

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    Despite recent progress in the diagnostic risk assessment of human adenovirus (HAdV) infections in immunocompromised patients, clinical complications mediated by these viruses continue contributing to significant morbidity and mortality, particularly in the pediatric hematopoietic allogeneic stem cell transplant (HSCT) setting. Current data highlight the importance of monitoring stool samples to assess the risk of invasive HAdV infections in children undergoing HSCT. The advent of novel, more effective antiviral treatment options might permit successful virus control even at the stage of systemic infection, thus increasing the interest in optimized HAdV monitoring in peripheral blood (PB). We have screened over 300 pediatric HCST recipients by serial monitoring of stool and PB specimens, and identified 31 cases of invasive HAdV infection by quantitative pan-adenovirus RQ-PCR analysis of consecutive PB specimens. The diagnostic parameters assessed included HAdV peak levels (PL) and the time-averaged area under the curve (AAUC) of virus copy numbers. The predictive value for patient outcome reflected by non-relapse and HAdV-related mortality was determined. The patients were assigned to quartiles based on their PL and AAUC, and the readouts were highly correlated (p < 0.0001). Non-relapse mortality in patients by AAUC quartile (lowest to highest) was 26, 50, 75, and 86%, respectively, and AAUC was strongly correlated with non-relapse mortality (p < 0.0001), while the association between PL and non-relapse mortality was less pronounced (p = 0.013). HAdV-related mortality was absent or very low in patients within the two lower quartiles of both PL and AAUC, and increased to ≥70% in the upper two quartiles. Despite the significant correlation of PL and AAUC with patient outcome, it is necessary to consider that the risk of non-relapse mortality even within the lowest quartile was still relatively high, and it might be difficult therefore to translate the results into differential treatment approaches. By contrast, the correlation with HAdV-related mortality might permit the identification of a low-risk patient subset. Nevertheless, the well-established correlation of HAdV shedding into the stool and intestinal expansion of the virus with the risk of invasive infection will expectedly remain an essential diagnostic parameter in the pediatric HSCT setting

    Silver nanoparticles with plasma-polymerized hexamethyldisiloxane coating on 3D printed substrates are non-cytotoxic and effective against respiratory pathogens

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    Due to the emerging resistance of microorganisms and viruses to conventional treatments, the importance of self-disinfecting materials is highly increasing. Such materials could be silver or its nanoparticles (AgNPs), both of which have been studied for their antimicrobial effect. In this study, we compared the biological effects of AgNP coatings with and without a plasma-polymerized hexamethyldisiloxane (ppHMDSO) protective film to smooth silver or copper coatings under three ambient conditions that mimic their potential medical use (dry or wet environments and an environment simulating the human body). The coatings were deposited on 3D printed polylactic acid substrates by DC magnetron sputtering, and their surface morphology was visualized using scanning electron microscopy. Cytotoxicity of the samples was evaluated using human lung epithelial cells A549. Furthermore, antibacterial activity was determined against the Gram-negative pathogenic bacterium Pseudomonas aeruginosa PAO1 and antiviral activity was assessed using human rhinovirus species A/type 2. The obtained results showed that overcoating of AgNPs with ppHMDSO creates the material with antibacterial and antiviral activity and at the same time without a cytotoxic effect for the surrounding tissue cells. These findings suggest that the production of 3D printed substrates coated with a layer of AgNPs-ppHMDSO could have potential applications in the medical field as functional materials

    The Effect of Non-lexical Verbal Signals on the Perceived Authenticity, Empathy and Understanding of a Listener

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    Active listening plays an important role in the relationship between clients and therapists. Here, we investigated whether variations of the confirmatory nonlexical verbal communication signal "mmh" influenced perceived authenticity, empathy and understanding of a listener. Eighty-one participants were in a conversation with an interviewer and reported about a difficult work experience. They were randomly assigned to one of three groups: The control group did not receive any verbal feedback from the interviewer; In one experimental group (1x-mmh), the interviewer uttered several monosyllabic confirmatory nonlexical verbal signals ("mmh") during the presentation; In a second experimental group (3x-mmh) the interviewer voiced several three syllable "mmh-mmh-mmh" while listening. All participants were then asked to rate the perceived authenticity, empathy and understanding of the interviewer. Participants in the 3x-mmh condition rated the interviewer to be significantly less authentic than those in the other two groups. No differences in reported empathy and understanding were found. The use of consecutive confirmatory nonlexical verbal signals ("mmh") - at least as currently implemented - may influence the perceived authenticity of a listener

    Countering Calcium Blooming With Personalized Contrast Media Injection Protocols: The 1-2-3 Rule for Photon-Counting Detector CCTA

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    OBJECTIVE Photon-counting detector computed tomography (PCD-CT) enables spectral data acquisition of CT angiographies allowing for reconstruction of virtual monoenergetic images (VMIs) in routine practice. Specifically, it has potential to reduce the blooming artifacts associated with densely calcified plaques. However, calcium blooming and iodine attenuation are inversely affected by energy level (keV) of the VMIs, creating a challenge for contrast media (CM) injection protocol optimization. A pragmatic and simple rule for calcium-dependent CM injection protocols is investigated and proposed for VMI-based coronary CT angiography with PCD-CT. MATERIALS AND METHODS A physiological circulation phantom with coronary vessels including calcified lesions (maximum CT value >700 HU) with a 50% diameter stenosis was injected into at iodine delivery rates (IDRs) of 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 2.5, and 3.0 g I/s. Images were acquired using a first-generation dual-source PCD-CT and reconstructed at various VMI levels (between 45 and 190 keV). Iodine attenuation in the coronaries was measured at each IDR for each keV, and blooming artifacts from the calcified lesions were assessed including stenosis grading error (as % overestimation vs true lumen). The IDR to achieve 300 HU at each VMI level was then calculated and compared with stenosis grading accuracy to establish a general rule for CM injection protocols. RESULTS Plaque blooming artifacts and intraluminal iodine attenuation decreased with increasing keV. Fixed windowing (representing absolute worst case) resulted in stenosis overestimation from 77% ± 4% at 45 keV to 5% ± 2% at 190 keV, whereas optimized windowing resulted in overestimation from 29% ± 3% at 45 keV to 4% ± 1% at 190 keV. The required IDR to achieve 300 HU showed a strong linear correlation to VMI energy (R2 = 0.98). Comparison of this linear plot versus stenosis grading error and blooming artifact demonstrated that multipliers of 1, 2, and 3 times the reference IDR for theoretical clinical regimes of no, moderate, and severe calcification density, respectively, can be proposed as a general rule. CONCLUSIONS This study provides a proof-of-concept in an anthropomorphic phantom for a simple pragmatic adaptation of CM injection protocols in coronary CT angiography with PCD-CT. The 1-2-3 rule demonstrates the potential for reducing the effects of calcium blooming artifacts on overall image quality

    Evaluating Quality of Service and Behavioral Reliability of Steer-by-Wire Systems

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    Best Paper Award on Factory Automation. Colloque avec actes et comité de lecture. internationale.International audienceSteer-by-wire systems must meet not only reliability but also real-time requirements. This paper presents an integrated approach for evaluating both the temporal performance and the behavioral reliability of Steer-by-wire systems taking into account the delay variation introduced by network transmission errors. The considered temporal performance is the Quality of Service perceived by the user, i.e. the vehicle stability. Tests in vehicles and simulations have been realized to estimate the maximum tolerable response time of the system, and to evaluate the impact of this delay on the Quality of Service. We quantify then the worst case response time of the system for a generic architecture based on TDMA protocol but independent of the communication network (could actually be TTP/C or FlexRay), and apply these generic results to a case study. We further define the notion of behavioral reliability as the probability that the worst case response time is less than a threshold. In our case study this behavioral reliability is evaluated and linked to the Safety Integrity Levels defined in IEC61508-1 standard. Based on this behavioral reliability concept, the final objective of our work is to propose a new dependability analysis method for X-by-Wire systems by taking into account both dynamic performance, fault-tolerance mechanisms and static redundancy of the system . || Les systèmes de direction électronique (steer-by-Wire) doivent respecter des contraintes à la fois de fiabilité et de temps réel. Ce papier présente une approche intégrée pour évaluer à la fois les performances temporelles et la fiabilité comportemental
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