Simulations of solar radiative transfer in measured and generated cloud fields

Um ein besseres Verständnis des Einflusses von Wolken auf den Strahlungstransport zu erlangen, müssen neben direkten Messungen der Strahlungsgrößen auch Strahlungstransportrechnungen durchgeführt werden. Dabei werden mikrophysikalische Eigenschaften aus Fernerkundungs- und in situ Messungen sowie generierte Wolkenfelder verwendet. In den BBC1- und BBC2 (= Baltex Bridge Cloud 1 und 2)-Messkampagnen wurden Messungen der mikrophysikalischen Wolkeneigenschaften und der Strahlungsgrößen durchgeführt. In diesem Bericht werden Ergebnisse von spektralen Monte Carlo Simulationen des Strahlungstransports in der Kurzwellenregion für Wellenlängen zwischen 350 nm und 850 nm für einen in BBC1 gemessenen Stratocumulus gezeigt. Zusätzlich wurden auch Strahlungstransportssimulationen für einen LES (= Large Eddy Simulation)- simulierten Cumulus und für eine entsprechende IAAFT (= Iterative Amplitude Adapted Fourier Transform)-Surrogatwolke mit denselben statistischen Eigenschaften wie die ursprüngliche Wolke durchgeführt.For a better understanding of the role that clouds play in the radiative transfer (RT) across the atmosphere, computer RT simulations with microphysical data retrieved from remote sensing and in situ measurements as well as with cloud fields provided by cloud generators have to be carried out in addition to field measurements campaigns. In this work we show spectral RT results for two cloud studies. During the BBC1 and BBC2 (=Baltex Bridge Cloud 1 and 2) campaigns measurements of cloud radiation and microphysics properties have been performed. We present here the results of a series of quasi-spectral simulations covering the shortwave region (from 350 nm up to 850 nm) for a remote-sensing captured stratocumulus. RT calculations have also been carried out for a LES (=Large Eddy Simulation) cumulus and an IAAFT (=Iterative Amplitude Adapted Fourier Transform) surrogate cloud with the same statistics as the original

Fault-tolerance thresholds for the surface code with fabrication errors

The construction of topological error correction codes requires the ability to fabricate a lattice of physical qubits embedded on a manifold with a non-trivial topology such that the quantum information is encoded in the global degrees of freedom (i.e. the topology) of the manifold. However, the manufacturing of large-scale topological devices will undoubtedly suffer from fabrication errors---permanent faulty components such as missing physical qubits or failed entangling gates---introducing permanent defects into the topology of the lattice and hence significantly reducing the distance of the code and the quality of the encoded logical qubits. In this work we investigate how fabrication errors affect the performance of topological codes, using the surface code as the testbed. A known approach to mitigate defective lattices involves the use of primitive SWAP gates in a long sequence of syndrome extraction circuits. Instead, we show that in the presence of fabrication errors the syndrome can be determined using the supercheck operator approach and the outcome of the defective gauge stabilizer generators without any additional computational overhead or the use of SWAP gates. We report numerical fault-tolerance thresholds in the presence of both qubit fabrication and gate fabrication errors using a circuit-based noise model and the minimum-weight perfect matching decoder. Our numerical analysis is most applicable to 2D chip-based technologies, but the techniques presented here can be readily extended to other topological architectures. We find that in the presence of 8% qubit fabrication errors, the surface code can still tolerate a computational error rate of up to 0.1%.Comment: 10 pages, 15 figure

Evaluating central bank asset purchases in a term structure model with a forward-looking supply factor

La literatura teórica de modelos de curva de tipos enfatiza la importancia de la absorción de riesgo de duración esperada durante la vida residual de los bonos para entender el efecto de las compras de activos de los bancos centrales sobre las curvas de tipos. Motivados por esto, construimos una medida de oferta esperada, a horizontes de largo plazo, de bonos soberanos del área del euro neta de tenencias del Eurosistema, y la empleamos para estimar el impacto de los programas de compra de activos del BCE en un modelo afín de curva de tipos sin arbitraje. Encontramos que un shock de compra de activos equivalente al 10 % del PIB del área del euro reduce el tipo medio a diez años de los cuatro grandes países del área del euro en 59 puntos básicos (pb) y la prima de plazo asociada en 50 pb. Aplicando el modelo a la curva de tipos libre de riesgo (OIS), el mismo shock reduce el tipo a diez años y la prima de plazo en 35 pb y 26 pb, respectivamente.The theoretical literature on term structure models emphasises the importance of the expected absorption of duration risk during the residual life of term bonds in order to understand the yield curve effect of central banks’ government bond purchases. Motivated by this, we develop a forward-looking, long-horizon measure of euro area government bond supply net of Eurosystem holdings, and use it to estimate the impact of the ECB’s asset purchase programmes in the context of a no-arbitrage affine term structure model. We find that an asset purchase shock equivalent to 10% of euro area GDP lowers the 10-year average yield of the euro area big four by 59 basis points (bp) and the associated term premium by 50 bp. Applying the model to the risk-free (OIS) yield curve, the same shock lowers the 10-year rate and term premium by 35 and 26 bp, respectively

Atmospheric methane with SCIAMACHY: Operational Level 2 data analysis and verification

SCIAMACHY is a passive imaging spectrometer mounted on board ESA’s ENVISAT satellite to probe a large number of atmospheric trace gas species, such as methane, and their global distribution and evolution. Methane (CH4) is particularly interesting as it is one of the most abundant greenhouse gas in the Earth atmosphere. To analyze SCIAMACHY methane measurements, we used the DLR BIRRA (Beer InfraRed Retrieval Algorithm) to retrieve nadir methane concentrations from its infrared spectra in channel 6. By integrating the DLR BIRRA code into ESAs operational Level 2 processor, we expanded it to include atmospheric CH4 column measurements. We have therefore performed an extensive test and verification operation. Our tests are based on separate comparisons with existing space and ground-based obtained measurements of methane column density. We present here our strategy for quality check of this first version of a CH4 product. We will further discuss specific geographical areas we used to validate the products

Thermal energy conversion by coupled shape memory and piezoelectric effects

International audienceThis work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE 'machine' which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE 'machine' with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations

Evaluating the GCN5b bromodomain as a novel therapeutic target against the parasite Toxoplasma gondii

Toxoplasma gondii is a protozoan parasite of great importance in human and veterinary health. The frontline treatment of antifolates suffers a variety of drawbacks, including toxicity and allergic reactions, underscoring the need to identify novel drug targets for new therapeutics to be developed. We previously showed that the Toxoplasma lysine acetyltransferase (KAT) GCN5b is an essential chromatin remodeling enzyme in the parasite linked to the regulation of gene expression. We have previously established that the KAT domain is a liability that can be targeted in the parasite by compounds like garcinol; here, we investigate the potential of the bromodomain as a targetable element of GCN5b. Bromodomains bind acetylated lysine residues on histones, which helps stabilize the KAT complex at gene promoters. Using an inducible dominant-negative strategy, we found that the GCN5b bromodomain is critical for Toxoplasma viability. We also found that the GCN5-family bromodomain inhibitor, L-Moses, interferes with the ability of the GCN5b bromodomain to associate with acetylated histone residues using an in vitro binding assay. Moreover, L-Moses displays potent activity against Toxoplasma tachyzoites in vitro, which can be overcome if parasites are engineered to over-express GCN5b. Collectively, our data support the GCN5b bromodomain as an attractive target for the development of new therapeutics

Coupling spin 'clock states' to superconducting circuits

A central goal in quantum technologies is to maximize GT2, where G stands for the rate at which each qubit can be coherently driven and T2 is the qubit's phase coherence time. This is challenging, as increasing G (e.g. by coupling the qubit more strongly to external stimuli) often leads to deleterious effects on T2. Here, we study a physical situation in which both G and T2 can be simultaneously optimized. We measure the coupling to microwave superconducting coplanar waveguides of pure (i.e. non magnetically diluted) crystals of HoW10 magnetic clusters, which show level anticrossings, or spin clock transitions, at equidistant magnetic fields. The absorption lines give a complete picture of the magnetic energy level scheme and, in particular, confirm the existence of such clock transitions. The quantitative analysis of the microwave transmission allows monitoring the overlap between spin wave functions and gives information about their coupling to the environment and to the propagating photons. The formation of quantum superpositions of spin-up and spin-down states at the clock transitions allows simultaneously maximizing the spin-photon coupling and minimizing environmental spin perturbations. Using the same experimental device, we also explore the coupling of these qubits to a 11.7 GHz cavity mode, arising from a nonperfect microwave propagation at the chip boundaries and find a collective spin to single photon coupling GN = 100 MHz. The engineering of spin states in molecular systems offers a promising strategy to combine sizeable photon-mediated interactions, thus scalability, with a sufficient isolation from unwanted magnetic noise sources.Comment: 7 pages, 5 figure

The zinc cluster protein Sut1 contributes to filamentation in Saccharomyces cerevisiae

Copyright © 2013, American Society for Microbiology. All Rights ReservedSut1 is a transcriptional regulator of the Zn(II)(2)Cys(6) family in the budding yeast Saccharomyces cerevisiae. The only function that has been attributed to Sut1 is sterol uptake under anaerobic conditions. Here, we show that Sut1 is also expressed in the presence of oxygen, and we identify a novel function for Sut1. SUT1 overexpression blocks filamentous growth, a response to nutrient limitation, in both haploid and diploid cells. This inhibition by Sut1 is independent of its function in sterol uptake. Sut1 downregulates the expression of GAT2, HAP4, MGA1, MSN4, NCE102, PRR2, RHO3, and RHO5. Several of these Sut1 targets (GAT2, HAP4, MGA1, RHO3, and RHO5) are essential for filamentation in haploids and/or diploids. Furthermore, the expression of the Sut1 target genes, with the exception of MGA1, is induced during filamentous growth. We also show that SUT1 expression is autoregulated and inhibited by Ste12, a key transcriptional regulator of filamentation. We propose that Sut1 partially represses the expression of GAT2, HAP4, MGA1, MSN4, NCE102, PRR2, RHO3, and RHO5 when nutrients are plentiful. Filamentation-inducing conditions relieve this repression by Sut1, and the increased expression of Sut1 targets triggers filamentous growth.The project was supported by Deutsche Forschungsgemeinschaft grant HO 2098/

Impaired antigen-specific B-cell responses after Influenza vaccination in kidney transplant recipients receiving co-stimulation blockade with Belatacept

Inhibidores de la calcineurina; Vacunación antigripal; Trasplante de riñónCalcineurin inhibitors; Influenza vaccination; Kidney transplantationInhibidors de la calcineurina; Vacunació antigripal; Trasplantament de ronyóEmerging data suggest that costimulation blockade with belatacept effectively controls humoral alloimmune responses. However, whether this effect may be deleterious for protective anti-infectious immunity remains poorly understood. We performed a mechanistic exploratory study in 23 kidney transplant recipients receiving either the calcineurin-inhibitor tacrolimus (Tac, n=14) or belatacept (n=9) evaluating different cellular immune responses after influenza vaccination such as activated T follicular Helper (Tfh), plasmablasts and H1N1 hemagglutinin (HA)-specific memory B cells (HA+mBC) by flow-cytometry, and anti-influenza antibodies by hemagglutination inhibition test (HI), at baseline and days 10, 30 and 90 post-vaccination. The proportion of CD4+CD54RA-CXCR5+ Tfh was lower in belatacept than Tac patients at baseline (1.86%[1.25-3.03] vs 4.88%[2.40-8.27], p=0.01) and remained stable post-vaccination. At M3, HA+mBc were significantly higher in Tac-treated patients (0.56%[0.32-1.49] vs 0.27%[0.13-0.44], p=0.04) and correlated with activated Tfh numbers. When stratifying patients according to baseline HA+mBc frequencies, belatacept patients with low HA+mBC displayed significantly lower HA+mBc increases after vaccination than Tac patients (1.28[0.94-2.4] vs 2.54[1.73-5.70], p=0.04). Also, belatacept patients displayed significantly lower seroprotection rates against H1N1 at baseline than Tac-treated patients (44.4% vs 84.6%) as well as lower seroconversion rates at days 10, 30 and 90 after vaccination (50% vs 0%, 63.6% vs 0%, and 63.6% vs 0%, respectively). We show the efficacy of belatacept inhibiting T-dependent antigen-specific humoral immune responses, active immunization should be highly encouraged before starting belatacept therapy.This work was supported by the Instituto de Salud Carlos III (ISCIII) (grant numbers ICI14/00242 and PI16/01321, PI19/01710) and by the European Union’s Horizon 2020 Research and innovation program (grant agreement 754995). Also, this work was partly supported by the SLT002/16/00183 grant, from the Department of Health of the Generalitat de Catalunya by the call “Accioí instrumental de programes derecerca orientats en l’àmbit de la recerca i la innovacioí en salut.” The authors thank the Research Centers of Catalonia (CERCA) Programme/Generalitat de Catalunya for institutional support. OB was awarded with an intensification grant from the “Instituto de Salud Carlos III” [INT19/00051]

‘Short Interest Pressure’ and Competitive Behaviour

This study introduces and examines a new-to-strategy form of Wall Street pressure – ‘short interest pressure’ – the tension felt by management caused by short sales of the firm\u27s stock. Drawing from a sample of over 5000 competitive actions carried out by competing firms over a 6-year time period, we test whether the level of short interest pressure experienced by the firm in one time period is predictive of properties of the firm\u27s competitive action repertoire in the ensuing time period. Our findings suggest that when faced with short interest pressure firms tend to carry out a higher number of competitive actions in the following time period, as well as a set of actions that deviate from the industry norm. In addition, post hoc analysis reveals that this effect is amplified for poorly performing firms. Thus, our study contributes to a deeper understanding of the relationship between capital market signals and competitive strategy