Comprendre la sécurité énergétique en Chine

La majorité des études portant sur la politique énergétique adopte un cadre d’analyse reposant sur les choix d’un acteur rationnel, soit sous la forme d’une Chine unitaire jouant sur la scène de la géopolitique de l’énergie, soit sous la forme d’une joute entre unités administratives cherchant à protéger leurs intérêts bureaucratiques. Cet article avance plutôt que les différentes mesures qui composent la politique énergétique chinoise sont le résultat d’un débat entre trois cadres de référence — une vision stratégique, une approche « de marché » et une conception de « développement scientifique » — présents simultanément au sein de la communauté politique du secteur de l’énergie. Ces cadres de référence servent de base à la définition des problèmes et à l’élaboration des solutions politiques. Il est cependant aussi nécessaire d’observer que certains facteurs structurels (culture économique, institutions politiques, procédures administratives, par exemple) imposent une sélection entre cadres de référence ou limitent leur conversion en politiques concrètes.Most research about China’s energy policy rely on a rational conception of political actors thus portraying China either under the guise of a rational unitary actor on the scene of energy geopolitics or as a battleground among administrative units protecting their bureaucratic turf. This article wants to shed a different light on China’s energy policy. It postulates that three different political frames — strategic, market, and “scientific development” — can be found within China’s energy policy community. These frames provide the cognitive foundations for problem definition and policy formulation. The measures forming the country’s energy policy are thus the result of debates between advocates of each frame and synthesis between them. Yet, some structural factors (economic culture, political institutions, and administrative procedures to name a few) impose a selection among those frames or limit their conversion into concrete policies

\theta^PMNS_13 = \theta_C / \sqrt2 from GUTs

The recent observations of the leptonic mixing angle \theta^PMNS_13 are consistent with \theta^PMNS_13 = \theta_C / \sqrt2 (with \theta_C being the Cabibbo angle \theta^CKM_12). We discuss how this relation can emerge in Grand Unified Theories (GUTs) via charged lepton corrections. The key ingredient is that in GUTs the down-type quark Yukawa matrix and the charged lepton Yukawa matrix are generated from the same set of GUT operators, which implies that the resulting entries are linked and differ only by group theoretical Clebsch factors. This allows a link \theta^e_12 = \theta_C to be established, which can induce \theta^PMNS_13 = \theta_C / \sqrt2 provided that the 1-3 mixing in the neutrino mass matrix is much smaller than \theta_C. We find simple conditions under which \theta^PMNS_13 = \theta_C / \sqrt2 can arise via this link in SU(5) GUTs and Pati-Salam models. We also discuss possible corrections to this relation. Using lepton mixing sum rules different neutrino mixing patterns can be distinguished by their predictions for the Dirac CP phase \delta^PMNS.Comment: v3: 18 pages, section on corrections to exact relation adde

How Transparency Measures Can Attenuate Initial Failures of Intelligent Decision Support Systems

Owing to high functional complexity, trust plays a critical role for the adoption of intelligent decision support systems (DSS). Especially failures in initial usage phases might endanger trust since users are yet to assess the system’s capabilities over time. Since such initial failures are unavoidable, it is crucial to understand how providers can inform users about system capabilities to rebuild user trust. Using an online experiment, we evaluate the effects of recurring explanations and initial tutorials as transparency measures on trust. We find that recurring explanations are superior to initial tutorials in establishing trust in intelligent DSS. However, recurring explanations are only as effective as tutorials or the combination of both tutorials and recurring explanations in rebuilding trust after initial failures occurred. Our results provide empirical insights for the design of transparency mechanisms for intelligent DSS, especially those with high underlying algorithmic complexity or potentially high damage

Visualizing intramolecular distortions as the origin of transverse magnetic anisotropy

The magnetic properties of metal–organic complexes are strongly influenced by conformational changes in the ligand. The flexibility of Fe-tetra-pyridyl-porphyrin molecules leads to different adsorption configurations on a Au(111) surface. By combining low-temperature scanning tunneling spectroscopy and atomic force microscopy, we resolve a correlation of the molecular configuration with different spin states and magnitudes of magnetic anisotropy. When the macrocycle exhibits a laterally undistorted saddle shape, the molecules lie in a S = 1 state with axial anisotropy arising from a square-planar ligand field. If the symmetry in the molecular ligand field is reduced by a lateral distortion of the molecule, we find a finite contribution of transverse anisotropy. Some of the distorted molecules lie in a S = 2 state, again exhibiting substantial transverse anisotropy

Electronic structure of an iron porphyrin derivative on Au(1 1 1)

Surface-bound porphyrins are promising candidates for molecular switches, electronics and spintronics. Here, we studied the structural and the electronic properties of Fe-tetra-pyridil-porphyrin adsorbed on Au(1 1 1) in the monolayer regime. We combined scanning tunneling microscopy/spectroscopy, ultraviolet photoemission, and two-photon photoemission to determine the energy levels of the frontier molecular orbitals. We also resolved an excitonic state with a binding energy of 420 meV, which allowed us to compare the electronic transport gap with the optical gap

Correlation of vibrational excitations and electronic structure with submolecular resolution

The detection of vibrational excitations of individual molecules on surfaces by scanning tunneling spectroscopy does not obey strict selection rules but rather propensity rules. The experimental verification of these excitations is challenging because it requires the independent variation of specific parameters, such as the electronic structure, while keeping the vibrational modes the same. Here, we make use of the versatile self-assembled structures of Fe-tetra-pyridyl-porphyrin molecules on a Au(111) surface. These molecules exhibit different energy-level alignments of the frontier molecular orbitals, thus allowing the correlation of the electronic structure and detection of vibrations. We identify up to seven vibrational modes in the tunneling spectra of the molecules in some of the arrangements, whereas we observe none in other structures. We find that the presence of vibrational excitations and their distribution along the molecule correlate with the observation of energetically low-lying molecular states. This correlation allows the explanation of the different numbers of vibrational signatures for molecules embedded within different structures as well as the bias asymmetry of the vibrational intensities within an individual molecule. Our observations are in agreement with the resonant enhancement of vibrations by the virtual excitation of electronic states

On the treatment effect heterogeneity of antidepressants in major depression: A Bayesian meta-analysis and simulation study

Background: The average treatment effect of antidepressants in major depression was found to be about 2 points on the 17-item Hamilton Depression Rating Scale, which lies below clinical relevance. Here, we searched for evidence of a relevant treatment effect heterogeneity that could justify the usage of antidepressants despite their low average treatment effect. Methods: Bayesian meta-analysis of 169 randomized, controlled trials including 58,687 patients. We considered the effect sizes log variability ratio (lnVR) and log coefficient of variation ratio (lnCVR) to analyze the difference in variability of active and placebo response. We used Bayesian random-effects meta-analyses (REMA) for lnVR and lnCVR and fitted a random-effects meta-regression (REMR) model to estimate the treatment effect variability between antidepressants and placebo. Results: The variability ratio was found to be very close to 1 in the best fitting models (REMR: 95% highest density interval (HDI) [0.98, 1.02], REMA: 95% HDI [1.00, 1.02]). The between-study standard deviation tau under the REMA with respect to lnVR was found to be low (95% HDI [0.00, 0.02]). Simulations showed that a large treatment effect heterogeneity is only compatible with the data if a strong correlation between placebo response and individual treatment effect is assumed. Conclusions: The published data from RCTs on antidepressants for the treatment of major depression is compatible with a near-constant treatment effect. Although it is impossible to rule out a substantial treatment effect heterogeneity, its existence seems rather unlikely. Since the average treatment effect of antidepressants falls short of clinical relevance, the current prescribing practice should be re-evaluated

Towards numerical prediction of flow-induced fiber displacements during wet compression molding (WCM)

Wet compression molding (WCM) provides large-scale production potential for continuous fiber-reinforced structural components due to simultaneous infiltration and draping during molding. Due to thickness-dominated infiltration of the laminate, comparatively low cavity pressures are sufficient – a considerable economic advantage. Experimental and numerical investigations prove strong mutual dependencies between the physical mechanisms, especially between resin flow (mold filling) and textile forming (draping), similar to other liquid molding techniques (LCM). Although these dependencies provide significant benefits such as improved contact, draping and infiltration capabilities, they may also lead to adverse effects such as flow-induced fiber displacement. To support WCM process and part development, process simulation requires a fully coupled approach including the capability to predict critical process effects. This work aims to demonstrate the suitability of a macroscopic, fully coupled, three-dimensional process simulation approach, to predict the process behavior during WCM, including flow-induced fiber displacements. The developed fluid model is superimposed to a suitable 3D forming model, which accounts for the deformation mechanisms including non-linear transverse compaction behavior. A strong Fluid-Structure-Interaction (FSI) enforced by Terzaghi’s law is applied to assess flow-induced fiber displacements during WCM within a porous UD-NCF stack in a homogenized manner. Accordingly, resulting local deformations are considered within the pressure field. All constitutive equations are formulated with respect to fiber deformation under finite strains. Results of a parametric study underline the relevance of contact conditions within the dry and infiltrated stack. The numerically predicted results are benchmarked and verified using both own and available experimental results from literature