Investigation of Anaplasma marginale Seroprevalence in a Traditionally Managed Large California Beef Herd.

Recent observations by stakeholders suggested that ecosystem changes may be driving an increased incidence of bovine erythrocytic anaplasmosis, resulting in a reemerging cattle disease in California. The objective of this prospective cohort study was to estimate the incidence of Anaplasma marginale infection using seroconversion in a northern California beef cattle herd. A total of 143 Black Angus cattle (106 prebreeding heifers and 37 cows) were enrolled in the study. Serum samples were collected to determine Anaplasma marginale seroprevalence using a commercially available competitive enzyme-linked immunosorbent assay test kit. Repeat sampling was performed in seronegative animals to determine the incidence density rate from March through September (2013). Seroprevalence of heifers was significantly lower than that of cows at the beginning of the study (P < 0.001) but not at study completion (P = 0.075). Incidence density rate of Anaplasma marginale infection was 8.17 (95% confidence interval: 6.04, 10.81) cases per 1000 cow-days during the study period. Study cattle became Anaplasma marginale seropositive and likely carriers protected from severe clinical disease that might have occurred had they been first infected as mature adults. No evidence was found within this herd to suggest increased risk for clinical bovine erythrocytic anaplasmosis

Preparation and spectroscopic studies of Hydroxyapatite embedded in Poly(N-Vinylpyrrolidone) matrix

Pure HAp powder was prepared by precipitation and HAp/PVP composites were prepared by casting technique. X-ray diffraction was performed to examine the crystallinity and the complexation between HAp and PVP when the amount of HAp increased. XRD and EDX analysis showed that the concentration 15 wt% is the most confirmation for the formation of HAp. SEM shows more than one form of HAp such as plates, needles and bundles in the morphological structure of pure HAp and 15 wt% of HAp. Two main weight loss regions and two peaks were observed in TGA and DSC thermograms that reveal reduction in the thermal stability of the prepared samples as HAp content increases. The activation energy of the films was decreased with increasing the concentration of HAp. DSC thermographs of the samples show that the values of the glass transition temperatures are decreased with increasing the content of HAp filler which suggest that HAp filler act as plasticizer. The conductivity–temperature plots show linear variation, which suggests an Arrhenius behavior. The conductivity increases with adding HAp content for low concentrations while decreased for the critical concentration (15 wt %) which confirms the XRD results

Wave Excitation in Disks Around Rotating Magnetic Stars

The accretion disk around a rotating magnetic star (neutron star, white dwarf or T Tauri star) is subjected to periodic vertical magnetic forces from the star, with the forcing frequency equal to the stellar spin frequency or twice the spin frequency. This gives rise bending waves in the disk that may influence the variabilities of the system. We study the excitation, propagation and dissipation of these waves using a hydrodynamical model coupled with a generic model description of the magnetic forces. The $m=1$ bending waves are excited at the Lindblad/vertical resonance, and propagate either to larger radii or inward toward the corotation resonance where dissipation takes place. While the resonant torque is negligible compared to the accretion torque, the wave nevertheless may reach appreciable amplitude and can cause or modulate flux variabilities from the system. We discuss applications of our result to the observed quasi-periodic oscillations from various systems, in particular neutron star low-mass X-ray binaries.Comment: Small changes/clarifications. To be published in ApJ, Aug.20,2008 issu

"Propeller" Regime of Disk Accretion to Rapidly Rotating Stars

We present results of axisymmetic magnetohydrodynamic simulations of the interaction of a rapidly-rotating, magnetized star with an accretion disk. The disk is considered to have a finite viscosity and magnetic diffusivity. The main parameters of the system are the star's angular velocity and magnetic moment, and the disk's viscosity, diffusivity. We focus on the "propeller" regime where the inner radius of the disk is larger than the corotation radius. Two types of magnetohydrodynamic flows have been found as a result of simulations: "weak" and "strong" propellers. The strong propeller is characterized by a powerful disk wind and a collimated magnetically dominated outflow or jet from the star. The weak propeller have only weak outflows. We investigated the time-averaged characteristics of the interaction between the main elements of the system, the star, the disk, the wind from the disk, and the jet. Rates of exchange of mass and angular momentum between the elements of the system are derived as a function of the main parameters. The propeller mechanism may be responsible for the fast spinning-down of the classical T Tauri stars in the initial stages of their evolution, and for the spinning-down of accreting millisecond pulsars.Comment: 18 pages, 16 figures, ApJ (accepted), added references, corrected typos; see animation at http://astrosun2.astro.cornell.edu/us-rus/disk_prop.ht

The Optimization of Microbus-Based Public Transportation Facilities in Jayapura City

Public transport services will work well if there is a balance between supply and demand. The research aimed to analyze the performance and the needs for the number of public transportation facilities based on the microbuses in Jayapura City. The types of the public transports, which would be discussed, were the microbuses which operated in 12 routes of the total routes of 26 in Jayapura city; those were B1, B2, B3, B4, J1, J2, K, I1, E, G, IA and I. The analyses of the performance and the demand for number of public transports were analyzed based on the load factor and the break event in accordance with the value of the vehicles operating costs (BOK) in setting tariffs. The research results indicated that the standard performance value of the public transport route code of K, I1, G, IA were categorized as less, while the routes of B1, B2, B3, B4, J1, J2, E and IB were categorized as medium. The microbuses demand was only 50% of the total microbuses now operating in Jayapura city

Magnetically Torqued Thin Accretion Disks

We compute the properties of a geometrically thin, steady accretion disk surrounding a central rotating, magnetized star. The magnetosphere is assumed to entrain the disk over a wide range of radii. The model is simplified in that we adopt two (alternate) ad hoc, but plausible, expressions for the azimuthal component of the magnetic field as a function of radial distance. We find a solution for the angular velocity profile tending to corotation close to the central star, and smoothly matching a Keplerian curve at a radius where the viscous stress vanishes. The value of this ''transition'' radius is nearly the same for both of our adopted B-field models. We then solve analytically for the torques on the central star and for the disk luminosity due to gravity and magnetic torques. When expressed in a dimensionless form, the resulting quantities depend on one parameter alone, the ratio of the transition radius to the corotation radius. For rapid rotators, the accretion disk may be powered mostly by spin-down of the central star. These results are independent of the viscosity prescription in the disk. We also solve for the disk structure for the special case of an optically thick alpha disk. Our results are applicable to a range of astrophysical systems including accreting neutron stars, intermediate polar cataclysmic variables, and T Tauri systems.Comment: 9 sharper figs, updated reference

Windbreak-Grown Casuarina and Eucalyptus Trees for Unbleached Kraft Pulp

A laboratory-scale evaluation was conducted of juvenile windbreak-grown Casuarina and Eucalyptus trees for kraft pulp production. Test results of unscreened pulp yields, pulp chemical analyses, and handsheet physical properties indicated that windbreak-grown materials are suitable for unbleached kraft pulp. Casuarina gave the best pulp yield and had higher tear strength than Eucalyptus, but both species were superior to kraft pulps from agricultural raw materials such as rice straw and Thymelia, which are currently used in Egypt. For both species, the best kraft pulping schedule tested was a 4:1 liquor-to-wood ratio with 20% active alkali with additional conditions constant. Scanning electron micrographs of handsheets helped explain the observed differences in physical properties between the two species. Mixing of Casuarina and Eucalyptus raw material prior to pulping shows promise for unbleached kraft pulp production

Perancangan Galeri Klub Sepakbola Arema Di Malang Dengan Metode Programatik Dan Semantik

Perkembangan sepakbola kian tahun makin berubah menjadi sebuah pertunjukan yang menghibur masyarakat umum. Saat ini, sepakbola dapat masuk ke setiap sisi sosial masyarakat mulai dari sosial tingkat bawah sampai tingkat atas. Karena begitu popular, olahraga sepak bola kini berkembang menjadi sebuah industri olahraga yang bertujuan komersial. Seperti yang telah diatur dalam Peraturan Mendagri, bahwa dana hibah APBD tidak dapat dialirkan langsung ke klub sepak bola di Indonesia. Sumber pendapatan klub yang dapat diperoleh dari luar klub adalah hak siar televisi, investor (football trust), dan sponsor. Sedangkan sumber dana yang berasal dari dalam klub sendiri yaitu penjualan tiket, merchandise, suporter, makanan dan supermarket. Saat ini belum ada pemusatan bisnis (industrialisasi) yang dilakukan oleh Arema sebagai klub professional. Galeri sebagai pusat income internal dari klub sepakbola Arema yang akan dirancang sesuai dengan permasalahan yang ada dengan memusatkan beberapa aspek pendapatan internal klub Arema. Perancangan Galeri Klub Sepakbola Arema di Malang ini menggunakan metode programatik, yaitu metode analisis terhadap data-data yang ada untuk menghasilkan sintesa atau keputusan, yaitu konsep perencanaan (planning). Konsep perencanaan tersebut menjadi bahan utama yang akan ditransformasi secara skematik menjadi konsep perancangan (designing). Metode yang akan diterapkan adalah Semantik Referensi dan Semantik Ekspresi untuk merancang tampilan bangunan yang mengidentitaskan (bermakna) persepakbolaan

Force-Free Models of Magnetically Linked Star-Disk Systems

Disk accretion onto a magnetized star occurs in a variety of astrophysical contexts, from young stars to X-ray pulsars. The magnetohydrodynamic interaction between the stellar field and the accreting matter can have a strong effect on the disk structure, the transfer of mass and angular momentum between the disk and the star, and the production of bipolar outflows, e.g., plasma jets. We study a key element of this interaction - the time evolution of the magnetic field configuration brought about by the relative rotation between the disk and the star - using simplified, largely semianalytic, models. We first discuss the rapid inflation and opening up of the magnetic field lines in the corona above the accretion disk, which is caused by the differential rotation twisting. Then we consider additional physical effects that tend to limit this expansion, such as the effect of plasma inertia and the possibility of reconnection in the disk's corona, the latter possibly leading to repeated cycles in the evolution. We also derive the condition for the existence of a steady state for a resistive disk and conclude that a steady state configuration is not realistically possible. Finally, we generalize our analysis of the opening of magnetic field lines by using a non-self-similar numerical model that applies to an arbitrarily rotating (e.g. keplerian) disk.Comment: 75 pages, 22 figures, 2 tables. Submitted to Astrophysical Journa

Warping and Precession of Accretion Disks Around Magnetic Stars: Nonlinear Evolution

The inner region of the accretion disk around a magnetized star (T Tauri star, white dwarf or neutron star) is subjected to magnetic torques that induce warping and precession of the disk. These torques arise from the interaction between the stellar field and the induced electric currents in the disk. We carry out numerical simulations of the nonlinear evolution of warped, viscous accretion disks driven by the magnetic torques. We show that the disk can develop into a highly warped steady state in which the disk attains a fixed (warped) shape and precesses rigidly. The warp is most pronounced at the disk inner radius (near the magnetosphere boundary). As the system parameters (such as accretion rate) change, the disk can switch between a completely flat state (warping stable) and a highly warped state. The precession of warped disks may be responsible for a variety of quasi-periodic oscillations or radiation flux variabilities observed in many different systems, including young stellar objects and X-ray binaries.Comment: 16 pages, 7 figures; extended parameter searches, changes in discussion; accepted for publication in Ap