5,378 research outputs found

    An algorithm for discrete fractional Hadamard transform

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    We present a novel algorithm for calculating the discrete fractional Hadamard transform for data vectors whose size N is a power of two. A direct method for calculation of the discrete fractional Hadamard transform requires N2N^2 multiplications, while in proposed algorithm the number of real multiplications is reduced to NNlog2N_2N.Comment: 22 pages, 4 figure

    Streamline topology and dilute particle dynamics in a Karman vortex street flow

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    Three types of streamline topology in a Karman vortex street flow are shown under the variation of spatial parameters. For the motion of dilute particles in the K\'arm\'an vortex street flow, there exist a route of bifurcation to a chaotic orbit and more attractors in a bifurcation diagram for the proportion of particle density to fluid density. Along with the increase of spatial parameters in the flow filed, the bifurcation process is suspended, as well as more and more attractors emerge. In the motion of dilute particles, a drag term and gravity term dominate and result in the bifurcation phenomenon.Comment: 16 pages, 9 figure

    Rotation numbers of invariant manifolds around unstable periodic orbits for the diamagnetic Kepler problem

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    In this paper, a method to construct topological template in terms of symbolic dynamics for the diamagnetic Kepler problem is proposed. To confirm the topological template, rotation numbers of invariant manifolds around unstable periodic orbits in a phase space are taken as an object of comparison. The rotation numbers are determined from the definition and connected with symbolic sequences encoding the periodic orbits in a reduced Poincar\'e section. Only symbolic codes with inverse ordering in the forward mapping can contribute to the rotation of invariant manifolds around the periodic orbits. By using symbolic ordering, the reduced Poincar\'e section is constricted along stable manifolds and a topological template, which preserves the ordering of forward sequences and can be used to extract the rotation numbers, is established. The rotation numbers computed from the topological template are the same as those computed from their original definition.Comment: 8 figures, 1 tabl

    A Comparison of Alcoholics Memories of their First Drinks as Compared to Non-Alcoholics

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    This study examined the relationship between alcoholics' memories of their first drinks as compared to non-alcoholics' memories of their first drinks. The participants were 36 members of Alcoholics Anonymous and 12 non-alcoholic volunteers (39 male, 8 female, 1 did not indicate gender). Results did not indicate a significant relationship between whether or not the participant was an alcoholic and the vividness of their memories of their first drink. However, results did indicate that alcoholics remembered their drink as being slightly more pleasant than non-alcoholics.B.A. (Bachelor of Arts

    Movements of Wolves at the Northern Extreme of the Species' Range, Including during Four Months of Darkness

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    Information about wolf (Canis lupus) movements anywhere near the northern extreme of the species' range in the High Arctic (>75°N latitude) are lacking. There, wolves prey primarily on muskoxen (Ovibos moschatus) and must survive 4 months of 24 hr/day winter darkness and temperatures reaching −53 C. The extent to which wolves remain active and prey on muskoxen during the dark period are unknown, for the closest area where information is available about winter wolf movements is >2,250 km south. We studied a pack of ≥20 wolves on Ellesmere Island, Nunavut, Canada (80°N latitude) from July 2009 through mid-April 2010 by collaring a lead wolf with a Global Positioning System (GPS)/Argos radio collar. The collar recorded the wolf's precise locations at 6:00 a.m. and 6:00 p.m. daily and transmitted the locations by satellite to our email. Straight-line distances between consecutive 12-hr locations varied between 0 and 76 km. Mean (SE) linear distance between consecutive locations (n = 554) was 11 (0.5) km. Total minimum distance traveled was 5,979 km, and total area covered was 6,640 km2, the largest wolf range reported. The wolf and presumably his pack once made a 263-km (straight-line distance) foray to the southeast during 19–28 January 2010, returning 29 January to 1 February at an average of 41 km/day straight-line distances between 12-hr locations. This study produced the first detailed movement information about any large mammal in the High Arctic, and the average movements during the dark period did not differ from those afterwards. Wolf movements during the dark period in the highest latitudes match those of the other seasons and generally those of wolves in lower latitudes, and, at least with the gross movements measurable by our methods, the 4-month period without direct sunlight produced little change in movements

    Potential of millimeter- and submillimeter-wave satellite observations for hydrometeor studies

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    The distribution of hydrometeors is highly variable in space and time, since it is the result of a complex chain of processes with scales from microphysical (1e-6 m) to synoptical (1e3 m). It is a challenging task to observe these highly variable atmospheric constituents on a global scale with a temporal and spatial resolution sufficient for numerical weather prediction (NWP) and hydrological purposes. This study investigates the potential of the millimeter- and submillimeter-wavelength range on space-borne sensors for hydrometeor and surface precipitation rate observations. The approach is based on simulations with cloud resolving models (CRMs) coupled to a radiative transfer (RT) model. The simulations are performed for mid-latitude cases covering a broad band of precipitation events such as heavy convective and light stratiform winter precipitation. Realistic atmospheric conditions were simulated with two mesoscale CRMs: the Meso-scale NonHydrostatic model (Meso-NH) on a 10 km and the COSMO-DE (COnsortium for Small-scale MOdeling-DEutschland) on a 2.8 km horizontal resolution. When calculating brightness temperatures for satellite observations with the one-dimensional radiative transfer model MWMOD (MicroWave MODel), the detailed cloud microphysics and the three-dimensional fields of temperature, humidity, and pressure of the CRMs are considered in the calculation of the interaction parameters. The model framework has been evaluated by comparing the simulated brightness temperature fields to observations of the Special Sensor Microwave Imager (SSM/I) as well as to those of the Advanced Microwave Sounding Unit-B (AMSU-B). The results show a good agreement as long as the CRMs capture the atmospheric situation correctly. Consequently, by coupling the radiative transfer model for microwave radiation to CRMs it is possible to evaluate these models through comparison to microwave satellite observations. Brightness temperatures for frequencies between 50 and 428 GHz at nine observation angles have been simulated for five mid-latitude cases at two time steps. In combination with the vertically integrated hydrometeor contents, these brightness temperature simulations have been used to set up a database. On the basis of this database simple retrieval algorithms have been developed to estimate the potential of the millimeter- and submillimeter-wavelength region for precipitation and hydrometeor observations. The results show, that especially for snow and graupel, the total column content can be retrieved accurately with relative errors smaller than 20% in stratiform precipitation cases over land and ocean surfaces. The performance for rain water path is similar to the one for graupel and snow in light precipitation cases. For the cases with higher precipitation amounts, the relative errors for rain water path are larger especially over land. The same behavior can be seen in the surface rain rate retrieval with the difference that the relative errors are doubled in comparison to the rain water path. Algorithms with a reduced number of frequencies show that window channels at higher frequencies are important for the surface rain rate retrieval. These are sensitive to the scattering in the ice phase related to the rain below. For the frozen hydrometeor retrieval, good results can be achieved by retrieval algorithms based only on frequencies at 150 GHz and above which are suitable for geostationary applications due to their reduced demands concerning the antenna size

    Adjunct Faculty on the Fringes: The Quest for Recognition and Support in Community Colleges

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    Although there are a growing number of adjunct faculty teaching the majority of students at many community colleges, some institutions have not initiated practices to cultivate and support adjunct faculty. The purpose of this qualitative phenomenological study was to use the voices of the adjuncts to gain insight into their lived experiences and expectations of support and recognition by the institutions they serve. Ten participants from four Central New York Community Colleges participated in this study. Semi-structured interviews were utilized as the primary source of data collection. Eight themes emerged, representing the participants’ experience that included: (a) inclusion, (b) inspiring students, (c) upward trajectory, (d) communication, (e) socialization, (f) challenges, (g) professional development, and (h) recognition. In the current study, adjunct faculty reported that they desire to belong to a collegial college community, work collaboratively with full-time faculty, and feel valued by their peers and the institution. The recommendations for changes to institutional practices discussed in this study could improve institutional recognition of adjuncts’ contributions to the overall quality of higher education and student success

    Reading social relations from Roman African mosaics – an iconographic analyse

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    The paper presents the diversity of Roman African society and the relations between different social groups by analysing the representations on the mosaics. It also analyses the manner of self-presentation of the landowners and their wives.The paper presents the diversity of Roman African society and the relations between different social groups by analysing the representations on the mosaics. It also analyses the manner of self-presentation of the landowners and their wives
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