365,464 research outputs found

    On the nonextensive character of some magnetic systems

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    During the past few years, nonextensive statistics has been successfully applied to explain many different kinds of systems. Through these studies some interpretations of the entropic parameter q, which has major role in this statistics, in terms of physical quantities have been obtained. The aim of the present work is to yield an overview of the applications of nonextensive statistics to complex problems such as inhomogeneous magnetic systems.Comment: to appear in the Proceedings of the conference CTNEXT07, Complexity, Metastability and Nonextensivity, Catania, Italy, 1-5 July 2007, Eds. S. Abe, H.J. Herrmann, P. Quarati, A. Rapisarda and C. Tsallis (American Institute of Physics, 2007) in pres

    Mobile dune fixation by a fast-growing clonal plant: a full life-cycle analysis

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    Desertification is a global environmental problem, and arid dunes with sparse vegetation are especially vulnerable to desertification. One way to combat desertification is to increase vegetation cover by planting plant species that can realize fast population expansion, even in harsh environments. To evaluate the success of planted species and provide guidance for selecting proper species to stabilize active dunes, demographic studies in natural habitats are essential. We studied the life history traits and population dynamics of a dominant clonal shrub Hedysarum laeve in Inner-Mongolia, northern China. Vital rates of 19057 ramets were recorded during three annual censuses (2007–2009) and used to parameterize Integral Projection Models to analyse population dynamics. The life history of H. laeve was characterized by high ramet turnover and population recruitment entirely depended on clonal propagation. Stochastic population growth rate was 1.32, suggesting that the populations were experiencing rapid expansion. Elasticity analysis revealed that clonal propagation was the key contributor to population growth. The capacity of high clonal propagation and rapid population expansion in mobile dunes makes H. laeve a suitable species to combat desertification. Species with similar life-history traits to H. laeve are likely to offer good opportunities for stabilizing active dunes in arid inland ecosystems

    Memories of the 1930s - FHKSC Radio Program

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    Interviews with Dr. Ray McCartney, Mrs. H.E. Malloy, Etta L. Wiest, H.J. Tholen, John Schaeffer, Frank and Marianne Anderson, John and Edna Zielke, Lydia Eichman, Helen Wise, and John Bird 00:00:00 - Introduction and background 00:01:16 - Introduction, Dr. Ray McCartney 00:04:42 - Teaching at Fort Hays in the 1930s during dust storms 00:09:54 - Introduction, Mrs. H.E. Malloy 00:10:19 - Keeping house during the dust storms 00:12:51 - Introduction, Etta Wiest 00:13:08 - The first dust storm in Hays. From here out the interviews are recorded over music which plays in reverse in the background. 00:17:05 - Introduction, H.J. Tholen 00:17:22 - Economy in Hays during the 1930s 00:25:40 - Introduction, John Schaeffer 00:25:48 - Welfare relief workers during the Dust Bowl 00:28:19 - Conclusion to the first half 00:29:20 - Introduction to the second half 00:30:47 - Introduction, Frank and Marianne Anderson 00:31:06 - Farming during the Dust Bowl 00:34:49 - Keeping house during the Dust Bowl 00:37:08 - Tall tale about a badger 00:37:38 - Introduction, John and Edna Zielke 00:37:45 - Farming and raising livestock during the Dust Bowl 00:44:07 - Introduction, Lydia Eichman 00:44:25 - Losing the farm as a result of the Dust Bowl 00:45:40 - Introduction, Helen Wise 00:45:52 - Challenges raising a family during the Dust Bowl 00:53L53 - Conclusionhttps://scholars.fhsu.edu/sackett/1147/thumbnail.jp

    Exoplanet Research with the Stratospheric Observatory for Infrared Astronomy (SOFIA)

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    When the Stratospheric Observatory for Infrared Astronomy (SOFIA) was conceived and its first science cases defined, exoplanets had not been detected. Later studies, however, showed that optical and near-infrared photometric and spectrophotometric follow-up observations during planetary transits and eclipses are feasible with SOFIA's instrumentation, in particular with the HIPO-FLITECAM and FPI+ optical and near infrared (NIR) instruments. Additionally, the airborne-based platform SOFIA has a number of unique advantages when compared to other ground- and space-based observatories in this field of research. Here we will outline these theoretical advantages, present some sample science cases and the results of two observations from SOFIA's first five observation cycles -- an observation of the Hot Jupiter HD 189733b with HIPO and an observation of the Super-Earth GJ 1214b with FLIPO and FPI+. Based on these early products available to this science case, we evaluate SOFIA's potential and future perspectives in the field of optical and infrared exoplanet spectrophotometry in the stratosphere.Comment: Invited review chapter, accepted for publication in "Handbook of Exoplanets" edited by H.J. Deeg and J.A. Belmonte, Springer Reference Work

    The Resurrection of the Single Scheme Exclusion to Rico\u27s Pattern Requirement

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    The article discusses the role of Racketeer Influenced and Corrupt Organizations Act (RICO) during criminal proceedings which have both criminal and civil liability for violations of prohibited activities. The U.S. Supreme Court case H.J. Inc. v. Northwestern Bell Telephone Co. in which the Court rejected the Eighth Circuit\u27s requirement of multiple schemes. The U.S. Court of Appeal for the Eighth Circuit held that a single scheme is not sufficient to satisfy the continuity element

    A possible black hole binary in Mkn 501

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    A simple binary model for Mkn~501 is considered under the assumption that the TeV and X-ray periodicity of ∌23\sim 23 days, observed during the flaring state in 1997, may be basically interpreted as a doppler-shifted flux modulation due to the orbital motion of the relativistic jet. For the typical jet properties inferred from emission models, we find an intrinsic orbital period of (6−14)(6-14) yrs and a centre-of-mass distance of (2−3.5)×1016(2-3.5) \times 10^{16} cm, the binary thus being a very close system. If the binary separation corresponds to that at which gravitational radiation becomes dominant, one may obtain a maximum allowed primary mass of ∌108M⊙\sim 10^8 M_{\odot} and a corresponding maximum allowed secondary mass in the range of ∌(1−9)×107M⊙\sim (1-9)\times 10^7 M_{\odot} assuming that gas accretion occurs on around the salpeter time scale. Interestingly such values agree with the black hole masses expected from merger scenarios.Comment: 4 pages, 2 figures; updated results of astro-ph/0005478; to appear in the Proc. of the Heidelberg International Symposium on High Energy Gamma-Ray Astronomy, Heidelberg, June 26-30, 2000, ed. by H.J. Voelk and F. Aharonian, AIP Conf. Pro

    Characterization Of Boron Doped Nanocrystalline Diamonds

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    Nanostructured diamond doped with boron was prepared using a hot-filament assisted chemical vapour deposition system fed with an ethyl alcohol, hydrogen and argon mixture. The reduction of the diamond grains to the nanoscale was produced by secondary nucleation and defects induced by argon and boron atoms via surface reactions during chemical vapour deposition. Raman measurements show that the samples are nanodiamonds embedded in a matrix of graphite and disordered carbon grains, while morphological investigations using field electron scanning microscopy show that the size of the grains ranges from 20 to 100 nm. The lowest threshold fields achieved were in the 1.6 to 2.4 V/Όm range. © 2008 IOP Publishing Ltd.100PART 5Himpsel, F.J., Knapp, J.A., VanVechten, J.A., Eastman, P.E., (1979) Phys. Rev., 20 B, p. 624Bandis, B., Pate, B.B., (1996) Appl. Phys Lett., 69, p. 366Mammana, V.P., Santos, T.E.A., Mammana, A., Baranauskas, V., Ceragioli, H.J., Peterlevitz, A.C., (2002) Appl. Phys. Lett., 81, p. 3470Baranauskas, V., Fontana, M., Ceragioli, H.J., Peterlevitz, A.C., (2004) Nanotech., 15 (10), pp. S678Shroder, R.E., Nemanich, R.J., Glass, J.T., (1990) Phys. Rev., 41 B, p. 3738Ferrari, A.C., Robertson, J., (2001) Phys. Rev., 63 B. , 121405(R)Jiang, X., Frederick, C.K.Au., Lee, S.T., (2002) J. Appl. Phys., 92 (5), p. 2880Lee, Y.C., Lin, S.J., Lin, I.N., Cheng, H.F., (2005) J. Appl. Phys., 97, p. 05431

    Le savoir-faire local dans la valorisation alimentaire des fruits du safoutier (Dacryodes edulis (G. Don) H.J. Lam) au Cameroun

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    The Local Know-how in the Valorisation of (Dacryodes edulis (G. Don) H.J. Lam) Fruits in Cameroon. Dacryodes edulis (G. Don) H.J. Lam (Burseraceae) is an oleaginous plant highly appreciated in the forest zone of Cameroon. This tree yields fruits called african pear or safou, highly consumed by local populations and even abroad. African pear is at the centre of a great economic activity in the Central Africa subregion as its trade generates cash for local traders during the production period. However, the valorisation of african pear is hindered by its high perishable nature responsible for important post-harvest losses due to lack of proper post-harvest handling. Some studies addressed the problem, unfortunately, nothing was done on the local know-how which has still to be investigated. The present paper sheds light on african pear local harvesting, handling and marketing practices in Cameroon. Field surveys were carried out in different production zones in Cameroon savannah and humid forest lowlands: Adamawa, centre, east, littoral and west provinces. Results showed that african pear occupies an important place in the population daily life. This multipurpose tree specie appears to be a source of foodstuffs, cash income, drugs and wood. If, on one hand diverse strategies are developed by the population for a proper conservation of fruits, on the other hand there is not a real fruits transformation activity. Results of this study highlight the traditional know-how and bring out prospects for future works on african pear valorisation

    Ambulatory estimation of foot movement during gait using inertial sensors

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    Human body movement analysis is commonly done in so-called 'gait laboratories’. In these laboratories, body movement is masured using optically based systems like Vicon, Optrotrak. The major drawback of these systems is the restriction to a laboratory environment. Therefore research is required to find ways for performing these measurements outside the gait laboratory. The estimation of foot movement is important, since balance is controlled by foot placement during gait. This study investigates whether it is possible to estimate foot movement, specifically foot placement, during gait under ambulatory conditions. The measurement system consisted of an orthopaedic sandal with two six degrees-of-freedom force/moment sensors beneath the heel and the forefoot. It should be noted that the force sensors were merely used for gait phase detection. The position and orientation of heel and forefoot were estimated using the accelerometers and gyroscopes of two miniature inertial sensors, rigidly attached to the force sensors [1,3]. In addition, errors in the walking direction were compensated for by using knowledge about the average walking direction. The proposed ambulatory measurement system was similar to the one used in a previous study [3]. In that study the position and orientation determination was restarted each step, while this study allows estimation of position and orientation during several steps including a change of direction. However, the accuracy should be investigated in more detail by an evaluation study. Moreover, the measurement system can be simplified by using a different gait phase detection system, for example by a gyroscope based detection system [2]. The financial support from the Dutch Ministry of Economic Affairs for the FreeMotion project is gratefully acknowledged. REFERENCES [1] H.J. Luinge and P.H. Veltink, “Measuring orientation of human body segments using miniature gyroscopes and accelerometers”, Med. Bio. Eng. Comp., Vol. 43, pp. 273-282, (2005). [2] I.P.I. Pappas, M.R. Popovic, M.R. Keller, V. Dietz and M. Morari, “A reliable gait phase detection system”, IEEE Trans. Neural Syst. Rehabil. Eng., Vol. 9, pp. 113-125, (2001). [3] H.M. Schepers, P.H. Veltink and H.F.J.M. Koopman, “Ambulatory assessment of ankle and foot dynamics”, IEEE Trans. Biomed. Eng., Submitted, (2006)
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