131 research outputs found

    Disorder-induced melting of the charge order in thin films of Pr0.5Ca0.5MnO3

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    We have studied the magnetic-field-induced melting of the charge order in thin films of Pr0.5Ca0.5MnO3 (PCMO) films on SrTiO3 (STO) by X-ray diffraction, magnetization and transport measurement. At small thickness (25 nm) the films are under tensile strain and the low-temperature melting fields are of the order of 20 T or more, comparable to the bulk value. With increasing film thickness the strain relaxes, which leads to a strong decrease of the melting fields. For a film of 150 nm, with in-plane and out-of-plane lattice parameters closer to the bulk value, the melting field has reduced to 4 T at 50 K, with a strong increase in the hysteretic behavior and also an increasing fraction of ferromagnetic material. Strain relaxation by growth on a template of YBa2Cu3O(7-delta) or by post-annealing yields similar results with an even stronger reduction of the melting field. Apparently, strained films behave bulk-like. Relaxation leads to increasing suppression of the CO state, presumably due to atomic scale disorder produced by the relaxation process.Comment: 7 pages, 4 fig

    Non-Fermi-liquid behavior in Ce(Ru1x_{1-x}Fex_x)2_2Ge2_2: cause and effect

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    We present inelastic neutron scattering measurements on the intermetallic compounds Ce(Ru1x_{1-x}Fex_x)2_2Ge2_2 (xx=0.65, 0.76 and 0.87). These compounds represent samples in a magnetically ordered phase, at a quantum critical point and in the heavy-fermion phase, respectively. We show that at high temperatures the three compositions have the identical response of a local moment system. However, at low temperatures the spin fluctuations in the critical composition are given by non-Fermi-liquid dynamics, while the spin fluctuations in the heavy fermion system show a simple exponential decay in time. In both compositions, the lifetime of the fluctuations is determined solely by the distance to the quantum critical point. We discuss the implications of these observations regarding the possible origins of non-Fermi-liquid behavior in this system.Comment: 4 figures, submitted to PR

    Proximity effects in the superconductor / heavy fermion bilayer system Nb / CeCu_6

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    We have investigated the proximity effect between a superconductor (Nb) and a 'Heavy Fermion' system (CeCu_6) by measuring critical temperatures TcT_c and parallel critical fields H_{c2}^{\parallel}(T) of Nb films with varying thickness deposited on 75 nm thick films of CeCu_6, and comparing the results with the behavior of similar films deposited on the normal metal Cu. For Nb on CeCu_6 we find a strong decrease of T_c with decreasing Nb thickness and a finite critical thickness of the order of 10 nm. Also, dimensional crossovers in H_{c2}^{\parallel}(T) are completely absent, in strong contrast with Nb/Cu. Analysis of the data by a proximity effect model based on the Takahashi-Tachiki theory shows that the data can be explained by taking into account both the high effective mass (or low electronic diffusion constant), {\it and} the large density of states at the Fermi energy which characterize the Heavy Fermion metal.Comment: 7 pages, 2 figure. Manuscript has been submitted to a refereed journa

    The Haroche-Ramsey experiment as a generalized measurement

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    A number of atomic beam experiments, related to the Ramsey experiment and a recent experiment by Brune et al., are studied with respect to the question of complementarity. Three different procedures for obtaining information on the state of the incoming atom are compared. Positive operator-valued measures are explicitly calculated. It is demonstrated that, in principle, it is possible to choose the experimental arrangement so as to admit an interpretation as a joint non-ideal measurement yielding interference and ``which-way'' information. Comparison of the different measurements gives insight into the question of which information is provided by a (generalized) quantum mechanical measurement. For this purpose the subspaces of Hilbert-Schmidt space, spanned by the operators of the POVM, are determined for different measurement arrangements and different values of the parameters.Comment: REVTeX, 22 pages, 5 figure

    All sky imaging-based short-term solar irradiance forecasting with Long Short-Term Memory networks

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    The intermittent nature of solar irradiance, primarily due to cloud movements, leads to rapid short-term fluctuations in the power output of photovoltaic (PV) systems. These fluctuations pose a significant challenge for integrating this renewable energy source into the power grid. Accurate forecasting of solar irradiance is not only crucial but also multi-beneficial. It enables more precise grid management by allowing operators to anticipate power output fluctuations and adjust energy distribution and storage strategies accordingly. This proactive approach reduces the reliance on backup power sources, which are often less sustainable and more expensive. Furthermore, accurate forecasts enhance the overall efficiency and reliability of energy systems by minimizing the impact of power variability on the grid, thereby supporting a more stable and sustainable energy supply. Addressing this need, our study focuses on the development of a forecasting model through innovative feature engineering, systematic design of specific attributes, and optimization of sequence length. The model is tailored to perform efficiently across various weather conditions and offers predictions for a time horizon of 0 to 20 min ahead. Utilizing a Long Short-Term Memory (LSTM) model, we achieve a remarkable ramp Forecast Skill Score of 39% in sunny and 25% in partially cloudy conditions. This work not only contributes to the existing literature but also presents a pioneering methodology for solar energy integration, highlighting the importance and application of accurate short-term solar irradiance forecasting

    An Evidence-Based Rationale for Dose De-escalation of Subcutaneous Atezolizumab

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    Background: Atezolizumab is a programmed death-ligand 1 (PD-L1) checkpoint inhibitor for the treatment of different forms of cancer. The subcutaneous formulation of atezolizumab has recently received approval. However, treatment with atezolizumab continues to be expensive, and the number of patients needing treatment with this drug continues to increase. Objective: We propose two alternative dosing regimens for subcutaneous atezolizumab to reduce drug expenses while ensuring effective exposure; one may be directly implemented in the clinic. Patients and Methods: We developed two alternative dose interval prolongation strategies based on pharmacokinetic modeling and simulation. The first dosing regimen was based on patients’ weight while maintaining equivalent systemic drug exposure by adhering to Food and Drug Administration (FDA) guidelines for in silico dose adjustments. The second dosing regimen aimed to have a minimum atezolizumab concentration above the 6 µg/mL threshold, associated with 95% intratumoral PD-L1 receptor saturation for at least 95% of all patients. Results: We found that, for the weight-based dosing regimen, the approved 3-week dosing interval could be extended to 5 weeks for patients &lt; 50 kg and 4 weeks for patients weighing 50–65 kg. Besides improving patient convenience, these alternative dosing intervals led to a predicted 7% and 12% cost reduction for either the USA or European population. For the second dosing regimen, we predicted that a 6-week dosing interval would result in 95% of the patients above the 6 µg/mL threshold while reducing costs by 50%. Conclusions: We have developed and evaluated two alternative dosing regimens that resulted in a cost reduction. Our weight-based dosing regimen can be directly implemented and complies with FDA guidelines for alternative dosing regimens of PD-L1 inhibitors. For the more progressive alternative dosing regimen aimed at the intratumoral PD-L1 receptor threshold, further evidence on efficacy and safety is needed before implementation.</p

    Effect of the Size of Clods Contained Covering Soil on the Seedling Emergence of Rice Plant Sown under Upland Field Condition

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    水稲農林23号を用いて, 覆土の土塊の大きさが, 乾田に深播き(覆土7cm)された個体の出芽ならびに幼苗諸器官の長さに及ぼす影響について, 覆土が3cmの場合と比較しながら検討した。乾田に播種された種子が大きい土塊で覆土されると, 覆土が3cmの場合には鞘葉の伸長が抑制される。しかし, 不完全葉はほとんどの個体で3cm以上に伸長する。また大土塊の間隙が小土塊で充足された場合は, 鞘葉および不完全葉ともに, 大土塊だけの場合よりも長くなる。その結果, すべての区の出芽率は, 播種後12日目には90%以上に達する。覆土が7cmの場合には, 覆土の土塊が大きくても, 鞘葉および不完全葉は覆土が3cmの場合よりも著しく長くなる。その結果, 第1本葉が不完全葉から抽出する位置が高められる。しかし, 鞘葉および不完全葉の伸長のみによっては出芽することはできず, 出芽するためには, 第2節間および第1本葉が伸長しなければならない。覆土の土塊が大きい場合には, 第2節間の伸長が抑制される。と同時に, 出芽までの間に幼芽の伸長を妨げる土塊の数も多くなるので, 出芽率は著しく低下する。しかし, 大土塊の間隙が小さい土塊によって充足されると, 第2節間が著しく長くなり, 第1本葉をおしあげる。その結果, 出芽率は単一土塊の場合に比べて著しく高まる。以上の結果と土壌中への光の侵入量との関係について, 若干考察した。 / This experiment was carried out to clarify the effects of size of clods in covering soil on the emergence and the elongation of rice seedling sown under upland field condition in pot (10cm×10cm×12cm) culture. Variety used was Norin No. 23. Seeds were covered with 3cm and 7cm depth of soil. In the case of 3cm in depth of seeding, if seeds were covered with larger clods, the elongation of coleoptile was inhibited, but the profile elongated longer than 3cm. When gaps between larger clods were filled with smaller clods, the length of coleoptile and profile became longer. Consequently, the emergence percentage of all plots reached more than 90% the 12th day after seeding. In the case of 7cm in depth of seeding, if seeds were covered with larger clods, coleoptile or profile elongated to 3 to 4cm in length, but the elongation of second internode was inhibited. As a result, the emergence percentage decreased significantly. When gaps between larger clods were filled with smaller clods, however, the length of second internode increased and first leaf was pushed up through the soil by second internode. Consequently, the emergence percentage increased significantly

    Consensus guidelines for the use and interpretation of angiogenesis assays

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    The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference
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