630 research outputs found
Governing Uncertainties in Sustainable Energy Transitions - Insights from Local Heat Supply in Switzerland
The governance of sustainable energy transitions (SET) is facing multiple technological, economic, societal and political uncertainties. In practice, these energy-related uncertainties play a role not only at the level of âmajor politics,â but also in the policymaking of local decision makers and planners. This paper seeks to attain a more differentiated understanding of how uncertainties concerning the energy transition play out and are dealt with in policymaking and planning âon the ground.â To do so, the paper combines conceptual reflections with an explorative empirical study on local heat supply policy in Switzerland. In conceptual regards, it proposes some distinctions of types of uncertainties related to energy transitions, and a typology of strategic decision options for dealing with uncertainty. On this basis, the paper reveals similarities and differences regarding the perception of uncertainties and ways of dealing with them in a number of Swiss cities. These insights evoke further questions about the causes and effects of different sensitivities to uncertainty and ways of dealing with them
Tailored Charge Transfer Kinetics in Precursors for Organic Radical Batteries: A Joint SyntheticâTheoretical Approach **
Abstract The development of sustainable energy storage devices is crucial for the transformation of our energy management. In this scope, organic batteries attracted considerable attention. To overcome the shortcomings of typically applied materials from the classes of redoxâactive conjugated polymers (i.âe., unstable cell voltages) and soft matterâembedded stable organic radicals (i.âe., low conductivity), a novel design concept was introduced, integrating such stable radicals within a conductive polymer backbone. In the present theoryâdriven design approach, redoxâactive (2,2,6,6âtetramethylpiperidinâ1âyl)oxyls (TEMPOs) were incorporated in thiopheneâbased polymer model systems, while structureâproperty relationships governing the thermodynamic properties as well as the charge transfer kinetics underlying the charging and discharging processes were investigated in a systematical approach. Thereby, the impact of the substitution pattern, the length as well as the nature of the chemical linker, and the ratio of TEMPO and thiophene units was studied using stateâofâtheâart quantum chemical and quantum dynamical simulations for a set of six molecular model systems. Finally, two promising candidates were synthesized and electrochemically characterized, paving the way to applications in the frame of novel organic radical batteries.Radical approach : Molecular models of stable organic radicals incorporated in a conjugated backbone, with application in the field of organic radical batteries, are investigated by means of multiconfigurational methods. The theoryâguided design allows to tune the charge transfer kinetics as well as the underlying thermodynamics. Auspicious systems are synthesized and characterized electrochemically. imag
Balloon dilatation and stenting for aortic coarctation: a systematic review and meta-analysis
BackgroundâThere is no systematic assessment of available evidence on effectiveness and comparative effectiveness of balloon dilatation and stenting for aortic coarctation. Methods and ResultsâWe systematically searched 4 online databases to identify and select relevant studies of balloon dilatation and stenting for aortic coarctation based on a priori criteria (PROSPERO 2014:CRD42014014418). We quantitatively synthesized results for each intervention from single-arm studies and obtained pooled estimates for relative effectiveness from pairwise and network meta-analysis of comparative studies. Our primary analysis included 15 stenting (423 participants) and 12 balloon dilatation studies (361 participants), including patients â„10 years of age. Post-treatment blood pressure gradient reduction to â€20 and â€10 mmâHg was achieved in 89.5% (95% confidence interval, 83.7â95.3) and 66.5% (44.1â88.9%) of patients undergoing balloon dilatation, and in 99.5% (97.5â100.0%) and 93.8% (88.5â99.1%) of patients undergoing stenting, respectively. Odds of achieving â€20 mmâHg were lower with balloon dilatation as compared with stenting (odds ratio, 0.105 [0.010â0.886]). Thirty-day survival rates were comparable. Numerically more patients undergoing balloon dilatation experienced severe complications during admission (6.4% [2.6â10.2%]) compared with stenting (2.6% [0.5â4.7%]). This was supported by meta-analysis of head-to-head studies (odds ratio, 9.617 [2.654â34.845]) and network meta-analysis (odds ratio, 16.23, 95% credible interval: 4.27â62.77) in a secondary analysis in patients â„1 month of age, including 57 stenting (3397 participants) and 62 balloon dilatation studies (4331 participants). ConclusionsâDespite the limitations of the evidence base consisting predominantly of single-arm studies, our review indicates that stenting achieves superior immediate relief of a relevant pressure gradient compared with balloon dilatation
Determination of the side-separated pulmonary right-toleft shunt volume
Background :With the present method of intrapulmonary right-to-left shunt volume calculation, no differentiation can be made between the shunt volume shares of the right and left lungs. For a better understanding of pathophysiological processes during thorax surgery with side-separated ventilation, a side-separated shunt volume determination would be useful. Materials and Methods : In 14 young female pigs, catheters were implanted into the left atrium after left thoracotomy. After transient clamping of the ipsilateral pulmonary veins, pulmonary venous blood was selectively obtained from the right lung. Cardiac output (CO) and side-separated pulmonary perfusion were determined with flowprobes at the pulmonary trunk and the left pulmonary artery. The shunt volumes were determined before and after thoracotomy during two-lung ventilation (Two-LV), after one-lung (right) ventilation (One-LV) with a continuous positive airway pressure (CPAP) of +7.5, +5.0 cm H2O, and under atelectasis of the non-dependent left lung (NDL). Results : After thoracotomy in lateral decubitus position and Two-LV, the shunt volumes of the two lungs differ. The right lung holds the major share (11.0±1.7%CO) [mean±SD]. The share of the left NDL is only 3.3±1.4. Under One-LV (right) and CPAP in the NDL, the total pulmonary shunt volume rises. This is caused by the increase in the NDL shunt volume share to 8.8±5.2 under CPAP +7.5 (p<0.05) and to 9.7±2.5 under CPAP +5.0 (p<0.05). Conclusions : The new intraoperative method of side-separated arterial blood gas analysis in conjunction with side-separated perfusion measurement makes side- separated rightto- left shunt volume determination possible and may lead to interesting new pathophysiological insights
Transcatheter Closure of Atrial Septal Defect with Carag Bioresorbable Septal Occluderâą: First-in-Child Experience with 12-MonthFollow-Up
BACKGROUND
Nowadays, transcatheter device closure of an atrial septal defect (ASD) is a standard approach in children. Potential early and long-term side effects or complications related to the metal framework of the devices are a known issue. A bioresorbable device such as the Carag Bioresorbable Septal Occluderâą (CBSO) could resolve such complications. Material and Results. The Carag Bioresorbable Septal Occluderâą (CBSO; Carag AG, Baar, Switzerland) is a self-centering double disk, repositionable, and retractable device with a bioresorbable framework (polylactic-co-glycolic acid), which is almost completely resorbed by 18-24âmonths postimplantation. This manuscript reports the four first-in-child ASD device closures using a CBSO. The patients' age was median (IQ1-IQ3), 4.5âyears (4-7.25). Weight was 21.3âkg (17.6-32.7). We demonstrated procedural feasibility and safety. Effective defect closure with the device was 100%. Echocardiographic measurements of the thickness of the interatrial septum did not show any relevant increase over a 12-monthfollow-up period. There were no residual defects found after the procedure or later during the resorption process. The patients showed no evidence of any local or systemic inflammatory reaction.
CONCLUSIONS
The CBSO device system could offer a new treatment option for transcatheter ASD device closure in the pediatric and adult fields. In our first-in-child experience, it was effectively and safely implanted. During the first 12 months of follow-up, no complications occurred
Interference of Clocks: A Quantum Twin Paradox
The phase of matter waves depends on proper time and is therefore susceptible
to special-relativistic (kinematic) and gravitational time dilation (redshift).
Hence, it is conceivable that atom interferometers measure general-relativistic
time-dilation effects. In contrast to this intuition, we show that light-pulse
interferometers without internal transitions are not sensitive to gravitational
time dilation, whereas they can constitute a quantum version of the
special-relativistic twin paradox. We propose an interferometer geometry
isolating the effect that can be used for quantum-clock interferometry.Comment: 9 Pages, 2 Figure
Unc13A and Unc13B contribute to the decoding of distinct sensory information in Drosophila
The physical distance between presynaptic Ca2+ channels and the Ca2+ sensors triggering the release of neurotransmitter-containing vesicles regulates short-term plasticity (STP). While STP is highly diversified across synapse types, the computational and behavioral relevance of this diversity remains unclear. In the Drosophila brain, at nanoscale level, we can distinguish distinct coupling distances between Ca2+ channels and the (m)unc13 family priming factors, Unc13A and Unc13B. Importantly, coupling distance defines release components with distinct STP characteristics. Here, we show that while Unc13A and Unc13B both contribute to synaptic signalling, they play distinct roles in neural decoding of olfactory information at excitatory projection neuron (ePN) output synapses. Unc13A clusters closer to Ca2+ channels than Unc13B, specifically promoting fast phasic signal transfer. Reduction of Unc13A in ePNs attenuates responses to both aversive and appetitive stimuli, while reduction of Unc13B provokes a general shift towards appetitive values. Collectively, we provide direct genetic evidence that release components of distinct nanoscopic coupling distances differentially control STP to play distinct roles in neural decoding of sensory information
The Effects of Intervention on Heart Power in Aortic Coarctation
Background In aortic coarctation, current guidelines recommend reducing
pressure gradients that exceed given thresholds. From a physiological
standpoint this should ideally improve the energy expenditure of the heart and
thus prevent long term organ damage. Objectives The aim was to assess the
effects of interventional treatment on external and internal heart power (EHP,
IHP) in patients with aortic coarctation and to explore the correlation of
these parameters to pressure gradients obtained from heart catheterization.
Methods In a collective of 52 patients with aortic coarctation 25 patients
received stenting and/or balloon angioplasty, and 20 patients underwent MRI
before and after an interventional treatment procedure. EHP and IHP were
computed based on catheterization and MRI measurements. Along with the power
efficiency these were combined in a cardiac energy profile. Results By
intervention, the catheter gradient was significantly reduced from 21.8±9.4 to
6.2±6.1mmHg (p<0.001). IHP was significantly reduced after intervention, from
8.03±5.2 to 4.37±2.13W (p < 0.001). EHP was 1.1±0.3 W before and 1.0±0.3W
after intervention, p = 0.044. In patients initially presenting with IHP above
5W intervention resulted in a significant reduction in IHP from 10.99±4.74 W
to 4.94±2.45W (p<0.001), and a subsequent increase in power efficiency from 14
to 26% (p = 0.005). No significant changes in IHP, EHP or power efficiency
were observed in patients initially presenting with IHP < 5W. Conclusion It
was demonstrated that interventional treatment of coarctation resulted in a
decrease in IHP. Pressure gradients, as the most widespread clinical
parameters in coarctation, did not show any correlation to changes in EHP or
IHP. This raises the question of whether they should be the main focus in
coarctation interventions. Only patients with high IHP of above 5W showed
improvement in IHP and power efficiency after the treatment procedure. Trial
Registration clinicaltrials.gov NCT0259194
Suffizienz im Alltag. Vielversprechende Schritte auf dem Weg zur Erreichung einer CO2-armen Gesellschaft
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