482 research outputs found

    Detection of extended millimeter emission in the host galaxy of 3C273 and its implications for QSO feedback via high dynamic range ALMA imaging

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    We estimate the amount of negative feedback energy injected into the ISM of the host galaxy of 3C273, a prototypical radio loud quasar. We obtained 93, 233 and 343 GHz continuum images with the Atacama Large Millimeter/Sub-millimeter Array (ALMA). After self calibration and point source subtraction, we reach an image dynamic range of 85000\sim 85000 at 93\ GHz, 39000\sim 39000 at 233\ GHz and 2500\sim 2500 at 343\ GHz. These are currently the highest image dynamic range obtained using ALMA. We detect spatially extended millimeter emission associated with the host galaxy, cospatial with the Extended Emission Line Region (EELR) observed in the optical. The millimeter spectral energy distribution and comparison with centimeter data show that the extended emission cannot be explained by dust thermal emission, synchrotron or thermal bremsstrahlung arising from massive star formation. We interpret the extended millimeter emission as thermal bremsstrahlung from gas directly ionized by the central source. The extended flux indicates that at least 7%\sim 7\% of the bolometric flux of the nuclear source was used to ionize atomic hydrogen in the host galaxy. The ionized gas is estimated to be as massive as 101010^{10} to 1011 M10^{11}\ \mathrm{M_\odot}, but the molecular gas fraction with respect to the stellar mass is consistent with other ellipticals, suggesting that direct ionization ISM by the QSO may not be sufficient to suppress star formation, or we are witnessing a short timescale before negative feedback becomes observable. The discovery of a radio counterpart to EELRs provides a new pathway to studying the QSO-host ISM interaction

    Observation of spin-exchange dynamics between itinerant and localized ¹⁷¹Yb atoms

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    We report on the observation of the spin-exchange dynamics of ¹⁷¹Yb atoms in the ground state ¹S₀ and in the metastable state ³P₀. We implement the mixed-dimensional two-orbital system using near-resonant and magic-wavelength optical lattices, where the ¹S₀ and ³P₀ atoms are itinerant in a one-dimensional tube and localized in three dimensions, respectively. By exploiting an optical Stern-Gerlach method, we observe the spin depolarization of the ¹S₀ atoms induced by the spin-exchange interaction with the ³P₀ atom. Our work could pave the way to the quantum simulation of the Kondo effect

    36M-pixel synchrotron radiation micro-CT for whole secondary pulmonary lobule visualization from a large human lung specimen

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    A micro-CT system was developed using a 36M-pixel digital single-lens reflex camera as a cost-effective mode for large human lung specimen imaging. Scientific grade cameras used for biomedical x-ray imaging are much more expensive than consumer-grade cameras. During the past decade, advances in image sensor technology for consumer appliances have spurred the development of biomedical x-ray imaging systems using commercial digital single-lens reflex cameras fitted with high megapixel CMOS image sensors. This micro-CT system is highly specialized for visualizing whole secondary pulmonary lobules in a large human lung specimen. The secondary pulmonary lobule, a fundamental unit of the lung structure, reproduces the lung in miniature. The lung specimen is set in an acrylic cylindrical case of 36 mm diameter and 40 mm height. A field of view (FOV) of the micro-CT is 40.6 mm wide × 15.1 mm high with 3.07 μm pixel size using offset CT scanning for enlargement of the FOV. We constructed a 13,220 × 13,220 × 4912 voxel image with 3.07 μm isotropic voxel size for three-dimensional visualization of the whole secondary pulmonary lobule. Furthermore, synchrotron radiation has proved to be a powerful high-resolution imaging tool. This micro-CT system using a single-lens reflex camera and synchrotron radiation provides practical benefits of high-resolution and wide-field performance, but at low cost

    Impact of cardiac support device combined with slow-release prostacyclin agonist in a canine ischemic cardiomyopathy model

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    BackgroundThe cardiac support device supports the heart and mechanically reduces left ventricular (LV) diastolic wall stress. Although it has been shown to halt LV remodeling in dilated cardiomyopathy, its therapeutic efficacy is limited by its lack of biological effects. In contrast, the slow-release synthetic prostacyclin agonist ONO-1301 enhances reversal of LV remodeling through biological mechanisms such as angiogenesis and attenuation of fibrosis. We therefore hypothesized that ONO-1301 plus a cardiac support device might be beneficial for the treatment of ischemic cardiomyopathy.MethodsTwenty-four dogs with induced anterior wall infarction were assigned randomly to 1 of 4 groups at 1 week postinfarction as follows: cardiac support device alone, cardiac support device plus ONO-1301 (hybrid therapy), ONO-1301 alone, or sham control.ResultsAt 8 weeks post-infarction, LV wall stress was reduced significantly in the hybrid therapy group compared with the other groups. Myocardial blood flow, measured by positron emission tomography, and vascular density were significantly higher in the hybrid therapy group compared with the cardiac support device alone and sham groups. The hybrid therapy group also showed the least interstitial fibrosis, the greatest recovery of LV systolic and diastolic functions, assessed by multidetector computed tomography and cardiac catheterization, and the lowest plasma N-terminal pro-B-type natriuretic peptide levels (P < .05).ConclusionsThe combination of a cardiac support device and the prostacyclin agonist ONO-1301 elicited a greater reversal of LV remodeling than either treatment alone, suggesting the potential of this hybrid therapy for the clinical treatment of ischemia-induced heart failure

    Sediment trapping in deltas of small mountainous rivers of southwestern Taiwan and its influence on East China Sea sedimentation

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    Taiwan's setting of high mountains, steep gradients, frequent earthquakes, erodible lithology, and heavy rainfall represents an ideal site to focus on sedimentary processes of the deltas of small mountainous rivers (SMRs). Several SMRs in southwestern Taiwan have deposited a thick sedimentary succession in the composite Southwest Taiwan Delta (SWTD) since the middle Holocene. Evidence from the SWTD can help to determine its trapping efficiency and assess the role of SMRs in sediment transport to the sea. We used historical nautical charts, bathymetric data, satellite radar data, and 14C dates to calculate the sediment volume of the SWTD on millennial and decadal scales. The 14C dates of core samples indicate deposition of thick deltaic sediment in subsiding areas since the time of the maximum flooding surface about 7 cal ka BP. The paleo-shoreline changes of the SWTD suggest a steady westward progradation since 7 cal ka BP. In contrast, the nautical charts suggest minor volume reduction of the offshore part of the SWTD, with a deepening trend and retreating shorelines, during the last seven decades. The results show that at least 201.72 ± 13.90 km3 (~3.23 105 Mt) of sediment has been trapped in the SWTD since 7 cal ka BP, and that the delta has shifted to a destructive phase during the past seven decades as human influences such as construction of reservoirs, dams, and weirs in the hills have reduced the sediment supply. The birth of the Taiwan Warm Current and following continuous sediment supply from the western rivers of Taiwan to the East China Sea since ~7.3 cal ka BP have played a crucial role in the sedimentation of the East China Sea, particularly in the Okinawa Trough, and the Japan Sea through the Tsushima Warm Current

    lithological and mineralogical investigations

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    The thesis contains 6 chapter and mentions about the influences of sea level change, climate, tectonic into the sedimentary process. The results show that late Pleistocene facies mostly are weathered facies which content gibbsite-kaolinite, limonite. In transgression, facies assemblage includes lagoon, tidal and estuary. The composition are in-situ reworked minerals like illite, gypsum. In regression, facies are shallow marine, prodelta, delta front, distributary lobe, swamp, tidal and beach, channel infill, flood plain, lake. Abundant minerals are named like smectite, illite, chlorite, quartz, feldspar, rock fragments, gypsum.Gypsum is the evaporited mineral easily to be formed in coastal environment of Red River Delta. It is a good indicative mineral for distinguishing the deposits formed in dry season of monsoon regions. Smectite is good indicative mineral for sea environment which mostly related with the transference and low accumulation and new formed in climate with wet and dry periods. Kaolinite-gibbsite is an indicator of strong chemical weathering with high precipitation. The stratigraphy can be divide into trangressive systems tract (10-8.5 cal. kyr BP) and highstand systems tract with aggradational-progradational parasequence set (8.5-6.5 cal. kyr BP) and progradational parasequence set (6.5 cal. kyr BP-today, with subsets 6.5-4.0; 4.0-1.5; and 1.5-0.0 cal. kyr BP). The subsidence process which reflex in accumulation rate regarded to not only sea level change, tectonics but also human impact - dyke build plays the main role to increased sedimentary thickness...Nordvietnam, Holocene sediment, Red River Delta, sea level changethesi
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