67 research outputs found

    Eliciting contextual temporal calibration:The effect of bottom-up and top-down information in reproduction tasks

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    Bayesian integration assumes that a current observation is integrated with previous observations. An example in the temporal domain is the central tendency effect: when a range of durations is presented, a regression towards the mean is observed. Furthermore, a context effect emerges if a partially overlapping lower and a higher range of durations is presented in a blocked design, with the overlapping durations pulled towards the mean duration of the block. We determine under which conditions this context effect is observed, and whether explicit cues strengthen the effect. Each block contained either two or three durations, with one duration present in both blocks. We provided either no information at the start of each block about the nature of that block, provided written ("short" / "long" or "A" / "B") categorizations, or operationalized pitch (low vs high) to reflect the temporal context. We demonstrate that (1) the context effect emerges as long as sufficiently distinct durations are presented; (2) the effect is not modulated by explicit instructions or other cues; (3) just a single additional duration is sufficient to produce a context effect. Taken together, these results provide information on the most efficient operationalization to evoke the context effect, allowing for highly economical experimental designs, and highlights the automaticity by which priors are constructed

    Electronic excitations stabilized by a degenerate electron gas in semiconductors

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    Excitons in semiconductors and insulators consist of fermionic subsystems, electrons and holes, whose attractive interaction facilitates bound quasiparticles with quasi-bosonic character. In the presence of a degenerate electron gas, such excitons dissociate due to free carrier screening. Despite their absence, we found pronounced emission traces in the below-band-edge region of bulk, germanium-doped GaN up to a temperature of 100 K, mimicking sharp spectral features at high free electron concentrations (3.4E19–8.9E19 cm−3). Our interpretation of the data suggests that a degenerate, three-dimensional electron gas stabilizes a novel class of quasiparticles, which we name collexons. These many-particle complexes are formed by exchange of electrons with the Fermi gas. The potential observation of collexons and their stabilization with rising doping concentration is enabled by high crystal quality due to the almost ideal substitution of host atoms with dopants.DFG, 43659573, SFB 787: Semiconductor Nanophotonics: Materials, Models, Device

    Suppression of the quantum-confined Stark effect in polar nitride heterostructures

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    Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

    The Formation of the Collisional Family around the Dwarf Planet Haumea

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    Haumea, a rapidly rotating elongated dwarf planet (~ 1500 km in diameter), has two satellites and is associated with a "family" of several smaller Kuiper Belt objects (KBOs) in similar orbits. All members of the Haumea system share a water ice spectral feature that is distinct from all other KBOs. The relative velocities between the Haumea family members are too small to have formed by catastrophic disruption of a large precursor body, which is the process that formed families around much smaller asteroids in the Main Belt. Here we show that all of the unusual characteristics of the Haumea system are explained by a novel type of giant collision: a graze-and-merge impact between two comparably sized bodies. The grazing encounter imparted the high angular momentum that spun off fragments from the icy crust of the elongated merged body. The fragments became satellites and family members. Giant collision outcomes are extremely sensitive to the impact parameters. Compared to the Main Belt, the largest bodies in the Kuiper Belt are more massive and experience slower velocity collisions; hence, outcomes of giant collisions are dramatically different between the inner and outer solar system. The dwarf planets in the Kuiper Belt record an unexpectedly large number of giant collisions, requiring a special dynamical event at the end of solar system formation.Comment: Accepted for publication in ApJ, 12 pages, 4 figures, 2 tables

    Evolutionary change in continuous reaction norms

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    Abstract Understanding the evolution of reaction norms remains a major challenge in ecology and evolution. Investigating evolutionary divergence in reaction norm shapes between populations and closely related species is one approach to providing insights. Here we use a meta-analytic approach to compare divergence in reaction norms of closely related species or populations of animals and plants across types of traits and environments. We quantified mean-standardized differences in overall trait means (Offset) and reaction norm shape (including both Slope and Curvature). These analyses revealed that differences in shape (Slope and Curvature together) were generally greater than differences in Offset. Additionally, differences in Curvature were generally greater than differences in Slope. The type of taxon contrast (species vs. population), trait, organism, and the type and novelty of environments all contributed to the best-fitting models, especially for Offset, Curvature, and the total differences (Total) between reaction norms. Congeneric species had greater differences in reaction norms than populations, and novel environmental conditions increased the differences in reaction norms between populations or species. These results show that evolutionary divergence of curvature is common and should be considered an important aspect of plasticity, together with slope. Biological details about traits and environments, including cryptic variation expressed in novel environmental conditions, may be critical to understanding how reaction norms evolve in novel and rapidly changing environments

    Propuesta de gestión logística en los almacenes de repuestos de la Distribuidora Santa Mónica S.A.C para reducir sus costos operacionales

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    RESUMEN La presente tesis es un trabajo de investigación que se enfoca en desarrollar un sistema de gestión logística en los almacenes de repuestos de una distribuidora, que incluye la adquisición, recepción, almacenamiento y correcta entrega de mercadería a los diversos clientes. El conocimiento y aplicación de indicadores y/o métodos permitirá administrar y gestionar; además será el inicio de una serie de acciones a realizar orientadas hacia la mejora continua. Las exigencias de los clientes respecto a la rápida atención de sus requerimientos son cada vez mayores, asimismo el mercado exige ser bastante competitivo en costos, por lo cual un elemento diferenciador, será el analizar la mejora en los procesos logísticos y eliminar todo lo que no genera valor, e identificar y eliminar las causas con la finalidad de automatización de procesos y reducción de los costos operacionales. Finalmente la gestión logística en los almacenes propuesto permite la fácil coordinación de información y distribución dentro del almacén que supera las expectativas del mercado local en una distribuidora generando un impacto positivo en la viabilidad económica tal como: VAN S/. 510,601.54 y TIR 107.37%, adicionalmente se logró desarrollar actividades logísticas de la empresa como: disminución de pérdidas en un 85%, aumento de atenciones a clientes y mayor rapidez del mismo en un 46% y disminución de pedidos en un 35%. Asimismo tiene como ventajas: validar información de proveedores, disminuir niveles de inventario, agilizar rotación artículos y coordinar efectivamente al personal.ABSTRACT The present thesis is a work of investigation that focuses in developing a system of logistic management in the repair parts stocks of a distributor, who includes the acquisition, reception, storage and correcto delivery of merchandise to the diverse clients. The knowledge and application of indicators and/or methods will allow to administer and to manage; in addition it will be the beginning of a series of action to realice oriented towards the continuous improvement. The exigencies of the clients with respect to the fast attention of their requirements are very time majors, also the market demands to be quite competitive in costs, thus an element differentiator, the improvement in the logistic processes will be to analyze and to eliminate everything what it does not generate value, and to identify and to eliminate the causes for the purposes of automatization of processes and reduction of the operational costs. Finally the logistic management in the warehouses proposed allows the easy coordination of information and distribution within the warehouse that surpasses the expectations of the local market in a distributor generating a positive impact in the economic viability as: VAN S/. 510,601.54 and TIR 107.37%, additionally were managed to develop logistics operations of the Company like: diminution of losses in a 85%, increase of attentions in clients and major rapidity of the same in a 46% and diminution of orders in a 35%. Also it has like advantages: to validate information of suppliers, to diminish inventory levels, to make agile rotation articles and to indeed coordinate the personnel

    Investigating the Atmospheric Mass Loss of the Kepler-105 Planets Straddling the Radius Gap

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    An intriguing pattern among exoplanets is the lack of detected planets between approximately 1.51.5 R_\oplus and 2.02.0 R_\oplus. One proposed explanation for this "radius gap" is the photoevaporation of planetary atmospheres, a theory that can be tested by studying individual planetary systems. Kepler-105 is an ideal system for such testing due to the ordering and sizes of its planets. Kepler-105 is a sun-like star that hosts two planets straddling the radius gap in a rare architecture with the larger planet closer to the host star (Rb=2.53±0.07R_b = 2.53\pm0.07 R_\oplus, Pb=5.41P_b = 5.41 days, Rc=1.44±0.04R_c = 1.44\pm0.04 R_\oplus, Pc=7.13P_c = 7.13 days). If photoevaporation sculpted the atmospheres of these planets, then Kepler-105b would need to be much more massive than Kepler-105c to retain its atmosphere, given its closer proximity to the host star. To test this hypothesis, we simultaneously analyzed radial velocities (RVs) and transit timing variations (TTVs) of the Kepler-105 system, measuring disparate masses of Mb=10.8±2.3M_b = 10.8\pm2.3 M_\oplus (ρb=0.97±0.22 \rho_b = 0.97\pm0.22 g cm3^{-3}) and Mc=5.6±1.2M_c = 5.6\pm1.2 M_\oplus (ρc=2.64±0.61\rho_c = 2.64\pm0.61 g cm3^{-3}). Based on these masses, the difference in gas envelope content of the Kepler-105 planets could be entirely due to photoevaporation (in 76\% of scenarios), although other mechanisms like core-powered mass loss could have played a role for some planet albedos.Comment: 14 pages, 3 figures, 2 table

    Baricitinib in patients with inadequate response or intolerance to conventional synthetic DMARDs: Results from the RA-BUILD study

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    Background Baricitinib is an oral, reversible, selective Janus kinase 1 and 2 inhibitor. Methods In this phase III, double-blind 24-week study, 684 biologic disease-modifying antirheumatic drug (DMARD)-naïve patients with rheumatoid arthritis and inadequate response or intolerance to ≥1 conventional synthetic DMARDs were randomly assigned 1:1:1 to placebo or baricitinib (2 or 4 mg) once daily, stratified by region and the presence of joint erosions. Endpoint measures included American College of Rheumatology 20% response (ACR20, primary endpoint), Disease Activity Score (DAS28) and Simplified Disease Activity Index (SDAI) score ≤3.3. Results More patients achieved ACR20 response at week 12 with baricitinib 4 mg than with placebo (62% vs 39%, p≤0.001). Compared with placebo, statistically significant improvements in DAS28, SDAI remission, Health Assessment Questionnaire-Disability Index, morning joint stiffness, worst joint pain and worst tiredness were observed. In a supportive analysis, radiographic progression of structural joint damage at week 24 was reduced with baricitinib versus placebo. Rates of adverse events during the treatment period and serious adverse events (SAEs), including serious infections, were similar among groups (SAEs: 5% for baricitinib 4 mg and placebo). One patient had an adverse event of tuberculosis (baricitinib 4 mg); one patient had an adverse event of non-melanoma skin cancer (baricitinib 4 mg). Two deaths and three major adverse cardiovascular events occurred (placebo). Baricitinib was associated with a decrease in neutrophils and increases in low-density and high-density lipoprotein. Conclusions In patients with rheumatoid arthritis and an inadequate response or intolerance to conventional synthetic DMARDs, baricitinib was associated with clinical improvement and inhibition of progression of radiographic joint damage
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