43 research outputs found

    The Interaction between the ISM and Star Formation in the Dwarf Starburst Galaxy NGC 4214

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    We present the first interferometric study of the molecular gas in the metal-poor dwarf starburst galaxy NGC 4214. Our map of the 12CO(1-0) emission, obtained at the OVRO millimeter array, reveals an unexpected structural wealth. We detected three regions of molecular emission in the north-west (NW), south-east (SE) and centre of NGC 4214 which are in very different and distinct evolutionary stages (total molecular mass: 5.1 x 10^6 M_sun). These differences are apparent most dramatically when the CO morphologies are compared to optical ground based and HST imaging: massive star formation has not started yet in the NW region; the well-known starburst in the centre is the most evolved and star formation in the SE complex started more recently. We derive a star formation efficiency of 8% for the SE complex. Using high--resolution VLA observations of neutral hydrogen HI and our CO data we generated a total gas column density map for NGC 4214 (HI + H_2). No clear correlation is seen between the peaks of HI, CO and the sites of ongoing star formation. This emphasizes the irregular nature of dwarf galaxies. The HI and CO velocities agree well, so do the H-alpha velocities. In total, we cataloged 14 molecular clumps in NGC 4214. Our results from a virial mass analysis are compatible with a Galactic CO-to-H_2 conversion factor for NGC 4214 (lower than what is usually found in metal-poor dwarf galaxies).Comment: accepted for publication in the AJ (February 2001), full ps file at: ftp://ftp.astro.caltech.edu/users/fw/ngc4214/walter_prep.p

    Protein hydrolysates from boarfish (Capros aper) and Atlantic salmon (Salmo salar) skin gelatin improve metabolic control in genetically obese diabetic (ob/ob) mice

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    There is increasing interest in dietary protein for management of Type 2 diabetes mellitus (T2DM) and obesity. The effects of twice-daily oral administration of a salmon skin gelatin hydrolysate (SSGH, 50 mg/kg), boarfish protein hydrolysate (BPH, (50 mg/kg), metformin (200 mg/kg), or saline control, were investigated in ob/ob mice. Non-fasting blood glucose was significantly reduced with SSGH (p < 0.01), BPH (p < 0.001) and metformin (p < 0.001), which were reflected in reductions in glycated haemoglobin (HbA1c) (p < 0.001, p < 0.01 and p < 0.01, respectively). Responses to oral and intraperitoneal glucose tolerance were improved (p < 0.05–0.01), as well as circulating plasma lipid profiles (p < 0.05–0.001). Chronic BPH treatment increased circulating plasma insulin (p < 0.01), whereas SSGH improved insulin sensitivity (p < 0.05), versus respective controls. All treatments significantly reduced energy intake (p < 0.05–0.001) versus (ob/ob) controls, without affecting overall bodyweight. These findings suggest that fish hydrolysates mediate potent anti-diabetic actions similar to metformin and might be suitable for the management and prevention of T2DM

    HST/WFPC2 and VLA Observations of the Ionized Gas in the Dwarf Starburst Galaxy NGC 4214

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    We present new H alpha and [O III] 5007 narrow band images of the starbursting dwarf galaxy NGC 4214, obtained with the WFPC2 onboard HST, together with VLA observations of the same galaxy. The HST images resolve features down to physical scales of 2-5 pc, revealing several young (<10 Myr) star forming complexes of various ionized gas morphologies (compact knots, complete or fragmentary shells) and sizes (10-200 pc). Our results are consistent with a uniform set of evolutionary trends: The youngest, smaller, filled regions that presumably are those just emerging from dense star forming clouds, tend to be of high excitation and are highly obscured. Evolved, larger shell-like regions have lower excitation and are less extincted due of the action of stellar winds and supernovae. In at least one case we find evidence for induced star formation which has led to a two-stage starburst. Age estimates based on W(H alpha) measurements do not agree with those inferred from wind-driven shell models of expanding H II regions. The most likely explanation for this effect is the existence of a 2 Myr delay in the formation of superbubbles caused by the pressure exerted by the high density medium in which massive stars are born. We report the detection of a supernova remnant embedded in one of the two large H II complexes of NGC 4214. The dust in NGC 4214 is not located in a foreground screen but is physically associated with the warm ionized gas.Comment: 41 pages, including 9 figures and 7 tables. To appear in the November issue of the Astronomical Journa

    The Assessment: EMU, Four Years On.

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    This paper reviews the functioning of the Economic and Monetary Union over the first 4 years of its existence. Monetary policy is viewed as having been of the "inflation-targeting" type, but with a tendency towards delay and conservatism in adjustment, which may also reflect over-optimistic output growth forecasts. The resulting pressure on the Stability and Growth Pact (SGP) illustrates the weakness in the "consensus view" of the harmonious interaction of monetary, fiscal, and supply-side policies, which requires policy in all three areas to be "correct". In discussing reform of the SGP, a looser but still constraining form of fiscal agreement is advocated. The supply-side and balance-of-payments issues involved in inter-country adjustment also interact importantly with the SGP and are identified as key areas of difficulty in a still "immature" monetary union, with separate labour-market structures. Here the mechanisms for coordination are more or less absent

    The Assessment: EMU four years on

    No full text
    This paper reviews the functioning of the Economic and Monetary Union over the first 4 years of its existence. Monetary policy is viewed as having been of the "inflation-targeting" type, but with a tendency towards delay and conservatism in adjustment, which may also reflect over-optimistic output growth forecasts. The resulting pressure on the Stability and Growth Pact (SGP) illustrates the weakness in the "consensus view" of the harmonious interaction of monetary, fiscal, and supply-side policies, which requires policy in all three areas to be "correct". In discussing reform of the SGP, a looser but still constraining form of fiscal agreement is advocated. The supply-side and balance-of-payments issues involved in inter-country adjustment also interact importantly with the SGP and are identified as key areas of difficulty in a still "immature" monetary union, with separate labour-market structures. Here the mechanisms for coordination are more or less absent
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