1,574 research outputs found

    Peranan Badan USAha Milik Desa ( Bumdes ) dalam Peningkatan Ekonomi Masyarakat ( Studi pada Bumdes Desa Pekan Tebih Kecamatan Kepenuhan Hulu Kabupaten Rokan Hulu )

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    This research aim to to know the Body Role of is Effort Countryside Property ( BUMDes) in Make-Up of Society Economics, specially society of consumer of fund BUMDes in Countryside of Week of Tebih of District of Fullness of Pate;Upstream of Sub-Province of Rokan Pate;Upstream. Research Population is some of consumer of fund of BUMDes of Countryside of Week of Tebih year 2013 counted 277 people and determination sampel use the method Proposional so that its sampel research amount to 42 people. In analysing research data use the descriptive method qualitative, only elaborating result from question interview the field momen

    Stochastic excitation of non-radial modes I. High-angular-degree p modes

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    Turbulent motions in stellar convection zones generate acoustic energy, part of which is then supplied to normal modes of the star. Their amplitudes result from a balance between the efficiencies of excitation and damping processes in the convection zones. We develop a formalism that provides the excitation rates of non-radial global modes excited by turbulent convection. As a first application, we estimate the impact of non-radial effects on excitation rates and amplitudes of high-angular-degree modes which are observed on the Sun. A model of stochastic excitation by turbulent convection has been developed to compute the excitation rates, and it has been successfully applied to solar radial modes (Samadi & Goupil 2001, Belkacem et al. 2006b). We generalize this approach to the case of non-radial global modes. This enables us to estimate the energy supplied to high-(â„“\ell) acoustic modes. Qualitative arguments as well as numerical calculations are used to illustrate the results. We find that non-radial effects for pp modes are non-negligible: - for high-nn modes (i.e. typically n>3n > 3) and for high values of â„“\ell; the power supplied to the oscillations depends on the mode inertia. - for low-nn modes, independent of the value of â„“\ell, the excitation is dominated by the non-diagonal components of the Reynolds stress term. We carried out a numerical investigation of high-â„“\ell pp modes and we find that the validity of the present formalism is limited to â„“<500\ell < 500 due to the spatial separation of scale assumption. Thus, a model for very high-â„“\ell pp-mode excitation rates calls for further theoretical developments, however the formalism is valid for solar gg modes, which will be investigated in a paper in preparation.Comment: 12 pages, accepted for publication in A&

    Solar-like oscillation amplitudes and line-widths as a probe for turbulent convection in stars

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    Excitation of solar-like oscillations is attributed to turbulent convection and takes place at the upper-most part of the outer convective zones. Amplitudes of these oscillations depend on the efficiency of the excitation processes as well as on the properties of turbulent convection. We present past and recent improvements on the modeling of those processes. We show how the mode amplitudes and mode line-widths can bring information about the turbulence in the specific cases of the Sun and Alpha Cen A.Comment: 9 pages ; 3 figures ; invited talk given during the Symposium no. 239 "Convection in Astrophysics", International Astronomical Union., held 21-25 August, 2006 in Prague, Czech Republi

    Solar-like oscillations in massive main-sequence stars. I. Asteroseismic signatures of the driving and damping regions

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    Motivated by the recent detection of stochastically excited modes in the massive star V1449 Aql (Belkacem et al., 2009b), already known to be a β\beta Cephei, we theoretically investigate the driving by turbulent convection. By using a full non-adiabatic computation of the damping rates, together with a computation of the energy injection rates, we provide an estimate of the amplitudes of modes excited by both the convective region induced by the iron opacity bump and the convective core. Despite uncertainties in the dynamical properties of such convective regions, we demonstrate that both are able to efficiently excite pp modes above the CoRoT observational threshold and the solar amplitudes. In addition, we emphasise the potential asteroseismic diagnostics provided by each convective region, which we hope will help to identify the one responsible for solar-like oscillations, and to give constraints on this convective zone. A forthcoming work will be dedicated to an extended investigation of the likelihood of solar-like oscillations across the Hertzsprung-Russell diagram.Comment: 9 pages, 14 figures, accepter in A&

    New bounds on the signed total domination number of graphs

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    In this paper, we study the signed total domination number in graphs and present new sharp lower and upper bounds for this parameter. For example by making use of the classic theorem of Turan, we present a sharp lower bound on this parameter for graphs with no complete graph of order r+1 as a subgraph. Also, we prove that n-2(s-s') is an upper bound on the signed total domination number of any tree of order n with s support vertices and s' support vertives of degree two. Moreover, we characterize all trees attainig this bound.Comment: This paper contains 11 pages and one figur
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