4,314 research outputs found

    Review of: Amer EI-Ahraf et al., The Impact of Public Policy on Environmental Quality and Health: The Case of Land Use Management and Planning

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    Review of the book The Impact of Public Policy on Environmental Quality and Health: The Case of Land Use Management and Planning by Amer El-Ahraf et al., (Quorum Books 1999). Acknowledgments, introduction, appendixes, selected bibliography, index. ISBN 1-56720-065-6 [181 pp. $59.95. Hardbound, 88 Post Road West, Westport, CT 06881]

    A search for solar-like oscillations in the Am star HD 209625

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    The goal is to test the structure of hot metallic stars, and in particular the structure of a near-surface convection zone using asteroseismic measurements. Indeed, stellar models including a detailed treatement of the radiative diffusion predict the existence of a near-surface convection zone in order to correctly reproduce the anomalies in surface abundances that are observed in Am stars. The Am star HD 209625 was observed with the Harps spectrograph mounted on the 3.6-m telescope at the ESO La Silla Observatory (Chile) during 9 nights in August 2005. This observing run allowed us to collect 1243 radial velocity (RV) measurements, with a standard deviation of 1.35 m/s. The power spectrum associated with these RV measurements does not present any excess. Therefore, either the structure of the external layers of this star does not allow excitation of solar-like oscillations, or the amplitudes of the oscillations remain below 20-30 cm/s (depending on their frequency range).Comment: 5 pages, 4 figures, A&A accepte

    Extraction of silymarin compounds from milk thistle (Silybum marianum) seed using hot, liquid water as the solvent

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    High-value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs occur. When compared to traditional solvents, water is an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A, and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50°C, 70°C, 85°C and 100°C water as a function of time. For taxifolin, silychristin, silybinin A, and silybinin B, extraction with 100°C water resulted in the highest yields. After 210 min of extraction at 100°C, the yield of taxifolin was 1.2 mg/g of seed while the yields of silychristin, silybinin A, and silybinin B were 5.0, 1.8 and 3.3 mg/g of seed, respectively. The ratios of the extracted compounds, and particularly the ratios at long extraction times, showed that the more polar compounds (taxifolin and silychristin) were preferentially extracted at 85°C, while the less polar silybinin was preferentially extracted at 100°C

    A unit on national government

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    Thesis (Ed.M.)--Boston UniversityThis paper deals with the problem of subdividing an over-sized unit in ninth-grade civics on the topic, national government, into three shorter units. Then the paper takes up, more extensively, the organization and presentation of the last of the three units according to the principles and procedures set down in Fundanentals of Secondary-School Teaching and the course in the Unit Method at Boston University under the direction of Professor Roy O. Billett

    Sovereignty under the Agreement on Government Procurement

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    Solar-like oscillations in the metal-poor subgiant nu Indi: II. Acoustic spectrum and mode lifetime

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    Convection in stars excites resonant acoustic waves which depend on the sound speed inside the star, which in turn depends on properties of the stellar interior. Therefore, asteroseismology is an unrivaled method to probe the internal structure of a star. We made a seismic study of the metal-poor subgiant star nu Indi with the goal of constraining its interior structure. Our study is based on a time series of 1201 radial velocity measurements spread over 14 nights obtained from two sites, Siding Spring Observatory in Australia and ESO La Silla Observatory in Chile. The power spectrum of the high precision velocity time series clearly presents several identifiable peaks between 200 and 500 uHz showing regularity with a large and small spacing of 25.14 +- 0.09 uHz and 2.96 +- 0.22 uHz at 330 uHz. Thirteen individual modes have been identified with amplitudes in the range 53 to 173 cm/s. The mode damping time is estimated to be about 16 days (1-sigma range between 9 and 50 days), substantially longer than in other stars like the Sun, the alpha Cen system or the giant xi Hya.Comment: 5 pages, 7 figures, A&A accepte

    The effect of pegbovigrastim on circulating neutrophil count in dairy cattle : a randomized controlled trial

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    Previous research in various species has shown that granulocyte-colony stimulating factor stimulates the production and release of neutrophils from bone marrow. The objective of this study was to characterize the effects of polyethylene glycol-bound bovine granulocyte colony-stimulating factor (pegbovigrastim; Imrestor, Elanco) on circulating leukocyte counts. Thirty-four Holstein cows were randomly assigned to receive 2 injections of either physiologic saline (n = 16) or pegbovigrastim (n = 18), 7 days before expected calving (d - 7) and within 24 hours after calving (d 0). Cows were sampled at d - 7, d - 6, d 0, d + 1, d + 7, and d +/- 21, relative to calving. Only cows for which the interval from the first injection to calving was >= 4 d and <= 10 d were included, such that the interval (mean +/- SD) from first treatment to calving was 6.7 +/- 1.9 d. Treatment effects were assessed with mixed linear regression models. After the first injection, neutrophil counts (x10(9)/L) in pegbovigrastim-treated cows increased from 4.3 (95% CI 3.8 to 4.8) at d - 7 to 18.2 (CI 16.3 to 20.3) at d - 6 (P < 0.0001). Their counts then decreased from d - 6 to d 0, when the second injection was administered, at a rate of - 0.31 x 10(9) neutrophils/L/day (P < 0.0001). After the second injection, neutrophil counts increased from 16.4 (CI 13.7 to 19.6) at d 0 to 32.8 (CI 25.2 to 42.7) at d + 1 (P < 0.0001), after which counts decreased at a rate of -3.73 x 10(9) neutrophils/L/day until d + 7 (P < 0.0001). Counts continued to decrease from d + 7 to d + 21 at a slower rate of -0.43 x 10(9) neutrophils/L/day (P < 0.0001), until baseline levels were reached. Conversely, in control cows, neutrophil counts were unchanged from d - 7 to d - 6 (P = 0.86) after the first injection and then decreased from 6.1 (CI 5.0-7.3) at d 0, to 3.2 (CI 2.4-4.2) at d + 1 (P < 0.0001) after the second injection. Neutrophil count was greater (P < 0.001) in pegbovigrastim-treated than in control cows at days -6, 0, +1 and +7. Area under the curve (cells x 10(9)/L per 28 d) for neutrophil counts in the pegbovigrastim group was 429, versus 99 in the control group (P < 0.0001). The response to each injection of pegbovigrastim was additive and consisted of 95% segmented neutrophils, suggesting that the effect of the treatment was to release mature neutrophils from a substantial pool available in the bone marrow. The sustained increase in circulating neutrophil count around the time of calving may contribute to improved health during the peripartum transition period

    Binaries among Ap and Am stars

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    The results of long-term surveys of radial velocities of cool Ap and Am stars are presented. There are two samples, one of about 100 Ap stars and the other of 86 Am stars. Both have been observed with the CORAVEL scanner from Observatoire de Haute-Provence (CNRS), France. The conspicuous lack of short-period binaries among cool Ap stars seems confirmed, although this may be the result of an observational bias; one system has a period as short as 1.6 days. A dozen new orbits could be determined, including that of one SB2 system. Considering the mass functions of 68 binaries from the literature and from our work, we conclude that the distribution of the mass ratios is the same for the Bp-Ap stars than for normal G dwarfs. Among the Am stars, we found 52 binaries, i.e. 60%; an orbit could be computed for 29 of them. Among these 29, there are 7 SB2 systems, one triple and one quadruple system. The 21 stars with an apparently constant radial velocity may show up later as long-period binaries with a high eccentricity. The mass functions of the SB1 systems are compatible with cool main-sequence companions, also suggested by ongoing spectral observations.Comment: 5 pages, 2 figures, to appear in: Proc. of the 26th workshop of the European Working Group on CP stars, Contrib. Astr. Obs. Skalnate Pleso Vol. 27, No

    Asteroseismology and calibration of alpha Cen binary system

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    Using the oscillation frequencies of alpha Cen A recently discovered by Bouchy & Carrier, the available astrometric, photometric and spectroscopic data, we tried to improve the calibration of the visual binary system alpha Cen. With the revisited masses of Pourbaix et al. (2002) we do not succeed to obtain a solution satisfying all the seismic observational constraints. Relaxing the constraints on the masses, we have found an age t_alpha Cen=4850+-500 Myr, an initial helium mass fraction Y_i = 0.300+-0.008, and an initial metallicity (Z/X)_i=0.0459+-0.0019, with M_A=1.100+-0.006M_o and M_B=0.907+-0.006M_o for alpha Cen A&B.Comment: accepted for publication as a letter in A&
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