4,168 research outputs found

    Pre-Miocene Paleogeographic Linkage Between e Korean peninsula and the Japanese Islands

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    Seoul National UniversityScedule:17-18 March 2003, Vemue: Kanazawa, Japan, Kanazawa Citymonde Hotel, Project Leader : Hayakawa, Kazuichi, Symposium Secretariat: XO kamata, Naoto, Edited by:Kamata, Naoto

    Consumer Privacy and Marketing Avoidance

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    We introduce consumer avoidance into analytical marketing research. We show that consumer efforts to conceal themselves and to deflect marketing have a crucial impact on sellers¡¯ marketing strategy. Under reasonable conditions, seller marketing is a strategic complement with consumer concealment. Hence, consumer measures to conceal themselves from marketing will increase its cost-effectiveness and lead sellers to market more. Policies that encourage consumers to conceal their identities would lead sellers to increase marketing. By contrast, policies that encourage consumers to deflect seller marketing would lead sellers to reduce marketing. Further, there is a clear need for public policy. To the extent of the externality from the sellers to consumers, the equilibrium levels of marketing (chosen by sellers) and concealment and deflection (chosen by consumers) exceed the social optimum.

    Double resonance of Raman transitions in a degenerate Fermi gas

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    We measure momentum-resolved Raman spectra of a spin-polarized degenerate Fermi gas of 173^{173}Yb atoms for a wide range of magnetic fields, where the atoms are irradiated by a pair of counterpropagating Raman laser beams as in the conventional spin-orbit coupling scheme. Double resonance of first- and second-order Raman transitions occurs at a certain magnetic field and the spectrum exhibits a doublet splitting for high laser intensities. The measured spectral splitting is quantitatively accounted for by the Autler-Townes effect. We show that our measurement results are consistent with the spinful band structure of a Fermi gas in the spatially oscillating effective magnetic field generated by the Raman laser fields.Comment: 7 pages, 6 figure

    Sales and Promotions: A More General Model

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    We embed the Varian (1980) model in a broader setting that considers how switcher/loyal customer segments are determined. Generally, customer acquisition is deterministic while pricing is randomized. The equilibrium outcome depends on the timing of customer acquisition relative to pricing. If sellers acquire customers before setting prices, the unique equilibrium is asymmetric. If sellers acquire customers and set prices simultaneously, the unique equilibrium is symmetric. Our results provide a fundamental justification for previous analyses that variously assumed the outcome to be asymmetric or symmetric. The comparative statics for the asymmetric and symmetric equilibria are identical.competition, pricing, customer acquisition

    Significado diagenético de las composiciones isotópicas de carbono, oxígeno y estroncio en la Formación Mural (Aptiense-Albiense, zona Cerro Pimas, norte de Sonora, México)

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    A carbon, oxygen and strontium isotopic study on the predominantly carbonate succession of the shallow marine Mural Formation in the Cerro Pimas locality of northern Sonora (Mexico) was undertaken to understand isotopic variations in seawater during Aptian- Albian time. Petrographic study has been carried out on these limestones to support the isotopic study. The limestones show low content of TOC, both negative and positive δ13C values (-4.1 to +2.2‰ VPDB) and d18O values varying from -13.4 to -8.9‰ VPDB. The carbon isotope composition, δ13C vs δ18O plot and Mn/Sr ratio suggest that the δ13C measured values are primary in nature and remain unaltered during diagenesis. The carbon isotope curve shows a positive δ13C excursion followed by a negative event in the lower part of the Los Coyotes Member (Lower Albian) of the Mural Formation and confirm the global nature of the episode OAE 1b in the Cerro Pimas section. The 87Sr/86Sr ratios for limestones of the Mural Formation (0.707221 to 0.707340) are similar to the ratios for Late Aptian and Early Albian seawater (0.70726 to 0.70740). In addition, 87Sr/86Sr age of the Cerro La Ceja member (113.4 Ma; Late Aptian age) is comparable to that of published zircon radiometric age. The numerical age of Los Coyotes (112.0 Ma and 111.1 Ma) and Cerro La Espina (110.9 Ma and 110.7 Ma) members indicate also Early Albian age. The whole-rock Sr isotope ages in this study are consistent with the previously published radiometric and biostratigraphic ages.En este trabajo se presenta un estudio isotópico de carbón, oxígeno y estroncio de la sucesión predominantemente carbonatada de la Formación Mural que aflora en la localidad de Cerro Pimas, norte de Sonora (México) con el fin de entender las variaciones isotópicas del agua de mar dentro de la cual se depositó esta unidad durante el Aptiense-Albiense. Los datos isotópicos están apoyados por un estudio petrográfico de las rocas carbonatadas. Las calizas tienen un contenido bajo de carbón orgánico total, valores negativos y positivos de δ13C (-4.1 a +2.2‰ VPDB) y valores de d18O entre -13.4 y -8.9 ‰. La composición de los isótopos de carbón, la relación δ13C vs δ18O y la proporción Mn/Sr sugieren que los valores medidos de δ13C son de naturaleza primaria y no fueron alterados durante la diagénesis. La curva de isótopos de carbón presenta una excursión positiva de δ13C seguida por un evento negativo en la parte inferior del Miembro Los Coyotes (Albiense inferior) de la Formación Mural y confirma la presencia del episodio global OAE 1b en la sección estudiada de Cerro Pimas. La relación 87Sr/86Sr de las calizas de la Formación Mural (0.707221 a 0.707340) es similar a la relación isotópica del agua de mar del Aptiense tardío y Albiense temprano (0.70726 a 0.70740). Además, una edad 87Sr/86Sr de 113.4 Ma (Aptiense tardío) que hemos obtenido para el Miembro Cerro La Ceja es similar a una edad radiométrica U-Pb en circones previamente publicada. Del mismo modo, hemos obtenido edades 87Sr/86Sr en roca total para los Miembros Los Coyotes (112.0 Ma and 111.1 Ma) y Cerro La Espina (110.9 Ma and 110.7 Ma) que confirman una edad Albiense temprano que es consistente con edades radiométricas y bioestratigráficas previamente reportadas

    Optimal Harvesting for an Age-Spatial-Structured Population Dynamic Model with External Mortality

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    We study an optimal harvesting for a nonlinear age-spatial-structured population dynamic model, where the dynamic system contains an external mortality rate depending on the total population size. The total mortality consists of two types: the natural, and external mortality and the external mortality reflects the effects of external environmental causes. We prove the existence and uniqueness of solutions for the population dynamic model. We also derive a sufficient condition for optimal harvesting and some necessary conditions for optimality in an optimal control problem relating to the population dynamic model. The results may be applied to an optimal harvesting for some realistic biological models

    Superconducting transition of a two-dimensional Josephson junction array in weak magnetic fields

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    The superconducting transition of a two-dimensional (2D) Josephson junction array exposed to weak magnetic fields has been studied experimentally. Resistance measurements reveal a superconducting-resistive phase boundary in serious disagreement with the theoretical and numerical expectations. Critical scaling analyses of the IVIV characteristics indicate contrary to the expectations that the superconducting-to-resistive transition in weak magnetic fields is associated with a melting transition of magnetic-field-induced vortices directly from a pinned-solid phase to a liquid phase. The expected depinning transition of vortices from a pinned-solid phase to an intermediate floating-solid phase was not observed. We discuss effects of the disorder-induced random pinning potential on phase transitions of vortices in a 2D Josephson junction array.Comment: 9 pages, 7 figures (EPS+JPG format), RevTeX

    Improved Real-Time Monocular SLAM Using Semantic Segmentation on Selective Frames

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    Monocular simultaneous localization and mapping (SLAM) is emerging in advanced driver assistance systems and autonomous driving, because a single camera is cheap and easy to install. Conventional monocular SLAM has two major challenges leading inaccurate localization and mapping. First, it is challenging to estimate scales in localization and mapping. Second, conventional monocular SLAM uses inappropriate mapping factors such as dynamic objects and low-parallax areas in mapping. This paper proposes an improved real-time monocular SLAM that resolves the aforementioned challenges by efficiently using deep learning-based semantic segmentation. To achieve the real-time execution of the proposed method, we apply semantic segmentation only to downsampled keyframes in parallel with mapping processes. In addition, the proposed method corrects scales of camera poses and three-dimensional (3D) points, using estimated ground plane from road-labeled 3D points and the real camera height. The proposed method also removes inappropriate corner features labeled as moving objects and low parallax areas. Experiments with eight video sequences demonstrate that the proposed monocular SLAM system achieves significantly improved and comparable trajectory tracking accuracy, compared to existing state-of-the-art monocular and stereo SLAM systems, respectively. The proposed system can achieve real-time tracking on a standard CPU potentially with a standard GPU support, whereas existing segmentation-aided monocular SLAM does not
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