277 research outputs found

    Low-frequency ocean bottom pressure variations in the North Pacific in response to time-variable surface winds

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    One decade of time-variable gravity field observations from the GRACE satellite mission reveals low-frequency ocean bottom pressure (OBP) variability of up to 2.5 hPa centered at the northern flank of the subtropical gyre in the North Pacific. From a 145 year-long simulation with a coupled chemistry climate model, OBP variability is found to be related to the prevailing atmospheric sea-level pressure and surface wind conditions in the larger North Pacific area. The dominating atmospheric pressure patterns obtained from the climate model run allow in combination with ERA-Interim sea-level pressure and surface winds a reconstruction of the OBP variability in the North Pacific from atmospheric model data only, which correlates favorably (r=0.7) with GRACE ocean bottom pressure observations. The regression results indicate that GRACE-based OBP observations are indeed sensitive to changes in the prevailing sea-level pressure and thus surface wind conditions in the North Pacific, thereby opening opportunities to constrain atmospheric models from satellite gravity observations over the oceans

    Analisis penerapan Area Traffic Control System (ATCS) di Pusat Kota Ambon

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    The Area Traffic Control System is part of the Intelligent Transportation System that coordinates traffic signaling devices according to real conditions in the field so as to have a positive influence on traffic at intersections and the transportation network as a whole. The study was conducted at six intersections that currently use traffic signal devices in Ambon city center. Based on the results of the Analytical Hierarchy Process, it was found that the most influential criterion is road performance with a weight of 58.4% compared to the other two criteria. Of the six intersections, Al-Fatah intersection has the highest total score. However, the total score of the other five intersections is also quite good. The application of this system is more advisable at intersections with good VC ration, spaced with the next intersection and located in commercial activity areas..Area Traffic Control System (ATCS) adalah bagian dari Intelligent Transportation System yang berfungsi  mengkoordinasi alat pemberi isyarat lalu lintas sesuai kondisi nyata di lapangan sehingga memberikan pengaruh positif pada lalu lintas di persimpangan dan jaringan transportasi secara keseluruhan. Oleh karena itu sebelum penerapannya, perlu diteliti faktor yang mempengaruhi pemilihan lokasi  penerapannya agar diterapkan di persimpangan yang tepat. Penelitian dilakukan pada enam persimpangan yang saat ini menggunakan alat pemberi isyarat lalu lintas di pusat kota Ambon. Dilakukan pencarian faktor dan sub faktor yang mempengaruhi pemilihan lokasi penerapan Area Traffic Control System di pusat kota Ambon dengan metode Analytical Hierarchy Process (AHP) yang akan digunakan sebagai bobot untuk analisis skoring untuk menentukan persimpangan yang cocok diterapkan sistem ini. Berdasarkan hasil Analytical Hierarchy Process, didapatkan faktor yang paling mempengaruhi adalah kinerja jalan, dengan bobot sebesar 58,4%. Penerapan sistem ATCS lebih disarankan pada persimpangan dengan VC ratio yang baik, berjarak tidak terlalu jauh dengan persimpangan berikutnya, dan terletak di kawasan aktivitas komersial. Dari enam persimpangan Al-Fatah memiliki skor total tertinggi, akan tetapi skor total lima persimpangan lainnya juga cukup baik, sehingga system ATCS dapat diterapkan di ke enam lokasi studi

    Salivary Metabolomic Signatures and Body Mass Index in Italian Adolescents: A Pilot Study

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    Context: Obesity surveillance is scarce in adolescents, and little is known on whether salivary metabolomics data, emerging minimally invasive biomarkers, can characterize metabolic patterns associated with overweight or obesity in adolescents. Objective: This pilot study aims to identify the salivary molecular signatures associated with body mass index (BMI) in Italian adolescents. Methods: Saliva samples and BMI were collected in a subset of n = 74 young adolescents enrolled in the Public Health Impact of Metal Exposure study (2007-2014). A total of 217 untargeted metabolites were identified using liquid chromatography-high resolution mass spectrometry. Robust linear regression was used to cross-sectionally determine associations between metabolomic signatures and sex-specific BMI-for-age z-scores (z-BMI). Results: Nearly 35% of the adolescents (median age: 12 years; 51% females) were either obese or overweight. A higher z-BMI was observed in males compared to females (P = .02). One nucleoside (deoxyadenosine) and 2 lipids (18:0-18:2 phosphatidylcholine and dipalmitoyl-phosphoethanolamine) were negatively related to z-BMI (P < .05), whereas 2 benzenoids (3-hydroxyanthranilic acid and a phthalate metabolite) were positively associated with z-BMI (P < .05). In males, several metabolites including deoxyadenosine, as well as deoxycarnitine, hyodeoxycholic acid, N-methylglutamic acid, bisphenol P, and trigonelline were downregulated, while 3 metabolites (3-hydroxyanthranilic acid, theobromine/theophylline/paraxanthine, and alanine) were upregulated in relation to z-BMI (P < .05). In females, deoxyadenosine and dipalmitoyl-phosphoethanolamine were negatively associated with z-BMI while deoxycarnitine and a phthalate metabolite were positively associated (P < .05). A single energy-related pathway was enriched in the identified associations in females (carnitine synthesis, P = .04). Conclusion: Salivary metabolites involved in nucleotide, lipid, and energy metabolism were primarily altered in relation to BMI in adolescents

    STIRAP transport of Bose-Einstein condensate in triple-well trap

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    The irreversible transport of multi-component Bose-Einstein condensate (BEC) is investigated within the Stimulated Adiabatic Raman Passage (STIRAP) scheme. A general formalism for a single BEC in M-well trap is derived and analogy between multi-photon and tunneling processes is demonstrated. STIRAP transport of BEC in a cyclic triple-well trap is explored for various values of detuning and interaction between BEC atoms. It is shown that STIRAP provides a complete population transfer at zero detuning and interaction and persists at their modest values. The detuning is found not to be obligatory. The possibility of non-adiabatic transport with intuitive order of couplings is demonstrated. Evolution of the condensate phases and generation of dynamical and geometric phases are inspected. It is shown that STIRAP allows to generate the unconventional geometrical phase which is now of a keen interest in quantum computing.Comment: 9 pages, 6 figures. To be published in Laser Physics (v. 19, n.4, 2009

    Indonesian Throughflow drove Australian climate form humid Pliocene to arid Pleistocene

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    Late Miocene to mid-Pleistocene sedimentary proxy records reveal that northwest Australia underwent an abrupt transition from dry to humid climate conditions at 5.5 million years (Ma), likely receiving year-round rainfall, but after ~3.3 Ma, climate shifted toward an increasingly seasonal precipitation regime. The progressive constriction of the Indonesian Throughflow likely decreased continental humidity and transferred control of northwest Australian climate from the Pacific to the Indian Ocean, leading to drier conditions punctuated by monsoonal precipitation. The northwest dust pathway and fully established seasonal and orbitally controlled precipitation were in place by ~2.4 Ma, well after the intensification of Northern Hemisphere glaciation. The transition from humid to arid conditions was driven by changes in Pacific and Indian Ocean circulation and regional atmospheric moisture transport, influenced by the emerging Maritime Continent. We conclude that the Maritime Continent is the switchboard modulating teleconnections between tropical and high-latitude climate systems.published_or_final_versio

    The behaviour of repeat visitors to museums: Review and empirical findings

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    This study presents a theoretical and operational framework for analysing repeat visit to museums. Starting from the literature on repeat visit in tourism, the specificities of these cultural attractions are made explicit through a review of theoretical and applied works. Consistently with previous contributors, the paper suggests that the analysis of actual past behaviours has to be preferred to the one of attitudes. The application of proper econometric models is also remarked in order to put into account individual profiles. Information coming from three techniques is then used in an integrated way in order to provide a more comprehensive view of the phenomenon. Evidence from an ad hoc survey suggests the necessity to give a greater attention to perceived cultural value during the visit, promoting cultural events during the week and addressed to children, and taking care of those visitors that come from far places also through an integrated tourist supply. © 2013 Springer Science+Business Media Dordrecht
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