Integrable Impurities as Boundary Conditions

A few exactly solvable interacting quantum many-body problems with impurities were previously reported to exhibit unusual features such as non-localization and absence of backscattering. In this work we consider the use of these integrable impurities as boundary conditions in the framework of linear transport problems. We first show that such impurities enhance the density of states at the Fermi surface, thus increasing the effective system size. The study of the real time-dynamics of a wave packet sent through a series of them inserted in both non-interacting and interacting leads then indicates that these impurities are transparent and do not add artefacts to the measurement of transport properties. We finally apply these new boundary conditions to study the conductance of an interacting scatterer using the embedding method.Comment: 6 figure

Sprachstandardisierung unter Mehrsprachigkeitsbedingungen. Das Deutsche in Luxemburg im 19. Jahrhundert

Der Beitrag beschreibt die Grundstruktur des Forschungsprojekts ‚Standardization in Diversity (SDiv). The case of German in Luxembourg 1795–1920‘, das im Zeitraum 2013–2016 vom Fonds National de la Recherche (Luxemburg) und der DFG gefördert wird. Weitere Informationen auf der Internetseite des Projekts unter http://infolux.uni.lu/standardization

Exact time-dependent density functional theory for impurity models

We employ the density matrix renormalization group to construct the exact time-dependent exchange correlation potential for an impurity model with an applied transport voltage. Even for short-ranged interaction we find an infinitely long-ranged exchange correlation potential which is built up {instantly} after switching on the voltage. Our result demonstrates the fundamental difficulties of transport calculations based on time-dependent density functional theory. While formally the approach works, important information can be missing in the ground-state functionals and may be hidden in the usually unknown non-equilibrium functionals

Cage-based small-pore catalysts for NH3-SCR prepared by combining bulky organic structure directing agents with modified zeolites as reagents

[EN] It has been possible to efficiently synthesize high-silica ERI and AFX zeolites with nano-sized primary crystallites (30-200 nm). This was achieved by using a dicationic and rigid organic structure directing agent (OSDA) that fits within the large cavities of these zeolites, and the use of FAU zeolites as initial Si and Al-sources. Cu- and Fe-based ERI and AFX materials were prepared following both post-synthetic cation exchange and direct synthesis methodologies, showing good activity for the selective catalytic reduction (SCR) of nitrogen oxide using ammonia. Accelerated hydrothermal ageing of the zeolites at high temperature (i.e. 750 degrees C) shows the necessity of removing the alkali cations remaining in the zeolites to obtain stable materials. Furthermore, the catalytic performance of the prepared Cu- and Fe-containing AFX catalyst, both before and after ageing treatment, approaches the catalytic activity of Cu- and Fe-CHA. (C) 2017 Elsevier B.V. All rights reserved.This work has been supported by Haldor Topsoe A/S, by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), and MAT2015-71261-R, by the European Union through ERC-AdG-2014-671093 (SynCatMatch) and by the Fundacion Ramon Areces through a research contract of the "Life and Materials Science" program. N. M. thanks MINECO for economical support through pre-doctoral fellowship (BES-2013-064347). The authors thank Isabel Millet for technical support.Martín-García, N.; Paris, C.; Vennestrom; Peter Nicolai Ravnborg; Thogersen, JR.; Corma Canós, A.; Moliner Marin, M. (2017). Cage-based small-pore catalysts for NH3-SCR prepared by combining bulky organic structure directing agents with modified zeolites as reagents. Applied Catalysis B Environmental. 217:125-136. https://doi.org/10.1016/j.apcatb.2017.05.082S12513621

Embedding method for the scattering phase in strongly correlated quantum dots

The embedding method for the calculation of the conductance through interacting systems connected to single channel leads is generalized to obtain the full complex transmission amplitude that completely characterizes the effective scattering matrix of the system at the Fermi energy. We calculate the transmission amplitude as a function of the gate potential for simple diamond-shaped lattice models of quantum dots with nearest neighbor interactions. In our simple models we do not generally observe an interaction dependent change in the number of zeroes or phase lapses that depend only on the symmetry properties of the underlying lattice. Strong correlations separate and reduce the widths of the resonant peaks while preserving the qualitative properites of the scattering phase.Comment: 11 pages, 3 figures. Proceedings of the Workshop on Advanced Many-Body and Statistical Methods in Mesoscopic Systems, Constanta, Romania, June 27th - July 2nd 2011. To appear in Journal of Physics: Conference Serie

Spatiotemporal regulation of lateral root organogenesis in Arabidopsis by cytokinin

The architecture of a plant's root system, established postembryonically, results from both coordinated root growth and lateral root branching. The plant hormones auxin and cytokinin are central endogenous signaling molecules that regulate lateral root organogenesis positively and negatively, respectively. Tight control and mutual balance of their antagonistic activities are particularly important during the early phases of lateral root organogenesis to ensure continuous lateral root initiation (LRI) and proper development of lateral root primordia (LRP). Here, we show that the early phases of lateral root organogenesis, including priming and initiation, take place in root zones with a repressed cytokinin response. Accordingly, ectopic overproduction of cytokinin in the root basal meristem most efficiently inhibits LRI. Enhanced cytokinin responses in pericycle cells between existing LRP might restrict LRI near existing LRP and, when compromised, ectopic LRI occurs. Furthermore, our results demonstrate that young LRP are more sensitive to perturbations in the cytokinin activity than are developmentally more advanced primordia. We hypothesize that the effect of cytokinin on the development of primordia possibly depends on the robustness and stability of the auxin gradient

NH3-SCR catalysts for heavy-duty diesel vehicles: Preparation of CHA-type zeolites with low-cost templates

Computer-assistance allows selecting the most adequate low-cost organic structure directing agents (OSDAs) for the crystallization of Al-rich CHA-type zeolites. The host-guest stabilization energies of tetraethylammonium (TEA), methyltriethylammonium (MTEA) and dimethyldiethylammonium (DMDEA), in combination with Na, were first theoretically evaluated. This “ab-initio” analysis reveals that two TEA show a serious steric hindrance in a cha cavity, whereas two MTEA would present excellent host-guest confinements. The synthesis of Al-rich CHA-type zeolites has been accomplished using TEA and MTEA. Electron diffraction and high-resolution transmission electron microscopy reveal large CHA-domains with narrow faulted GME-domains in the CHA-type material synthesized with TEA, confirming the better OSDA-directing roles of MTEA cations towards the cha cavity, in good agreement with DFT calculations. Cu-exchanged Al-rich CHA-type samples achieved with MTEA and TEA show excellent catalytic activity and hydrothermal stability for the selective catalytic reduction (SCR) of NOx with ammonia under conditions relevant for future heavy duty diesel conditions.This work has been supported by Umicore and by the Spanish Government-MCIU through RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE) and PID2020-112590GB-C21 (AEI/FEDER, UE). T.W. acknowledges financial support by the Swedish Research Council (Grant No. 2019-05465). E.B. acknowledges the Spanish Government-MCIU for a FPI scholarship (PRE2019-088360). P.F. thanks ITQ for a contract. The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. The computations were performed on the Tirant III cluster of the Servei d'Informàtica of the University of Valencia

Iron deficiency contributes to resistance to endogenous erythropoietin in anaemic heart failure patients

Aims Abnormal endogenous erythropoietin (EPO) constitutes an important cause of anaemia in chronic diseases. We analysed the relationships between iron deficiency (ID) and the adequacy of endogenous EPO in anaemic heart failure (HF) patients, and the impact of abnormal EPO on 12-month mortality. Methods and results We investigated 435 anaemic HF patients (age: 74 +/- 10 years; males: 60%; New York Heart Association class I or II: 39%; left ventricular ejection fraction: 43 +/- 17%). Patients with EPO higher than expected for a given haemoglobin were considered EPO-resistant whereas those with EPO lower than expected - EPO-deficient. ID was defined as serum ferriti

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Sprachstandardisierung unter Mehrsprachigkeitsbedingungen: Das Deutsche in Luxemburg im 19. Jahrhundert

Der Beitrag behandelt Aspekte der Standardisierung des Deutschen in Luxemburg während des ‚langen’19. Jahrhunderts. Luxemburg ist durch eine weit zurück reichende Mehrsprachigkeit gekennzeichnet und bildet so ein willkommenes Beispiel, um Sprachstandardisierung unter Mehrsprachigkeits-bedingungen zu untersuchen. Sprachstandardisierung, verstanden als Selekti-on, Kodifikation, Implementierung und Ausbau von Normen (Haugen 1966), wurde bisher weitgehend unter nationalsprachlichen oder komparativen Ge-sichtspunkten (vgl. Vandenbussche 2007) betrachtet. Hingegen wurden As-pekte der Mehrsprachigkeit und des Sprachkontakts sowohl in der empiri-schen Beschreibung wie auch in der Theoriebildung kaum berücksichtigt. Um diese Forschungslücke zu füllen, werden diese Faktoren im hier vorgestellten Ansatz zentralgesetzt