1,095 research outputs found
Bimodality in low-luminosity E and S0 galaxies
Stellar population characteristics are presented for a sample of low-luminosity early-type galaxies (LLEs) in order to compare them with their more luminous counterparts. Long-slit spectra of a sample of 10 LLEs were taken with the ESO New Technology Telescope, selected for their low luminosities. Line strengths were measured on the Lick standard system. Lick indices for these LLEs were correlated with velocity dispersion (σ), alongside published data for a variety of Hubble types. The LLEs were found to fall below an extrapolation of the correlation for luminous ellipticals and were consistent with the locations of spiral bulges in plots of line strengths versus σ. Luminosity weighted average ages, metallicities and abundance ratios were estimated from χ2 fitting of 19 Lick indices to predictions from simple stellar population models. The LLEs appear younger than luminous ellipticals and of comparable ages to spiral bulges. These LLEs show a bimodal metallicity distribution, consisting of a low-metallicity group (possibly misclassified dwarf spheroidal galaxies) and a high-metallicity group (similar to spiral bulges). Finally, they have low α-element to iron peak abundance ratios indicative of slow, extended star formation
The Structure, Kinematics and Physical Properties of the Molecular Gas in the Starburst Nucleus of NGC 253
We present 5.2" x 2.6" resolution interferometry of CO J=1-0 emission from
the starburst galaxy NGC 253. The high spatial resolution of these new data, in
combination with recent high resolution maps of 13CO, HCN and near-infrared
emission, allow us for the first time to link unambiguously the gas properties
in the central starburst of NGC 253 with its bar dynamics. We confirm that the
star formation results from bar-driven gas flows as seen in "twin peaks"
galaxies. Two distinct kinematic features are evident from the CO map and
position-velocity diagram: a group of clouds rotating as a solid body about the
kinematic center of the galaxy, and a more extended gas component associated
with the near-infrared bar. We model the line intensities of CO, HCN and 13CO
to infer the physical conditions of the gas in the nucleus of NGC 253. The
results indicate increased volume densities around the radio nucleus in a
twin-peaks morphology. Compared with the CO kinematics, the gas densities
appear highest near the radius of a likely inner Linblad resonance, and
slightly lead the bar minor axis. This result is similar to observations of the
face-on, twin-peaks galaxy NGC 6951, and is consistent with models of starburst
generation due to gas inflow along a bar.Comment: To appear in the ApJ, 28 pages, 12 figure file
Frequency and predictors of thrombus inside the guiding catheter during interventional procedures: an optical coherence tomography study
Optical coherence tomography (OCT) is able to identify thrombus. We detect the frequency of thrombus inside the guiding catheter by OCT and its relationship with clinical and procedural factors. We screened 77 patients who underwent OCT pullbacks. Only patients with visible guiding catheter were finally included (35) and divided into thrombus (21) or no-thrombus group (14). Patients within thrombus group were mostly males (100 vs. 71 %, p = 0.05), with acute coronary syndrome (76 vs. 36 %, p = 0.02) and received more frequently percutaneous coronary intervention (86 vs. 43 %, p = 0.01) as compared to other group. A second dose of heparin was more frequently administered in thrombus than in other group (86 vs. 50 %, p = 0.01). Time between first heparin administration and OCT pullback (41[28–57] vs. 20 min [10–32], p = 0.001), time elapsed from second heparin administration and OCT pullback (29 [19–48] vs. 16 min [12–22], p = 0.002) and total procedural time (47 [36–69] vs. 31 min [26–39], p = 0.005) were longer in thrombus compared to other group. At multivariate analysis, total procedural time and time between first heparin administration and OCT pullback were only predictors of intra-catheter thrombus (HR 0.6 [0.3–0.9], p = 0.03 and HR 1.9 [1.1–3.2], p = 0.02, respectively). Thrombus inside guiding catheter may be a frequent finding in long interventional procedure. Future studies are warranted to determine its clinical impact
Strategies and options for increasing and sustaining fisheries and aquaculture production to benefit poorer households in Asia [PDF in letter standard]
The last three decades have wi tnessed dramatic changes in the structure of supply and demand for fish, especially in Asia. This WorldFish research study sponsored by the Asian Development Bank focussed on nine developing countries û Bangladesh, China, India, Indonesia, Malaysia, the Philippines, Sri Lanka, Thailand, and Vietnam, all active players in the transformation of global fish supply and demand. The study, broken into five components and reported here, considered: 1) the profile of key aquaculture technologies and fishing practices; 2) analysis of policies, institutions and support services; 3) socioeconomic profile of major stakeholders in the fisheries sector; 4) projections of fish demand and supply in the nine Asian countries; and 5) formulation of national action plans based on the findings and recommendations of the study.Research, Fisheries, Economic analysis, Aquaculture, Fish consumption, Trade, Policies, Socioeconomic aspects, Technology, Fishery products, Asia, China, People's Rep., Bangladesh, India, Indonesia, Malaysia, Philippines, Malaysia, Sri Lanka, Thailand, Vietnam,
Tensile Properties and Microstructures of Laser-Formed Ti-6Al-4V
The room temperature tensile properties of Ti-6Al-4V alloy prepared under two different processing routes were evaluated and compared. One group of samples was prepared by conventional casting-forging-rolling into flat plates. The other group was prepared by using Triton\u27s Laser Free-Form Fabrication (LF3)(TM) processes, i.e., a laser was used to melt pre-alloyed powders of the required metallic composition as they were dropped onto a moveable substrate programmed to move in such a manner as to form a solid alloy plate. Five populations of Ti-6Al-4V were evaluated: a standard wrought form, an as-deposited form, a machined as-deposited form, a heat-treated as-deposited form, and a machined as-deposited and heat-treated form. The poorest mechanical properties occurred with the rough surfaces, likely due to existing microcracks and stress concentrations. The LF3 (TM) as-deposited material had mechanical properties comparable to, if not higher than, the mechanical properties of the wrought material. Further evaluations of the laser-formed material for complex spacecraft piece parts were warranted, specifically in regards to improving the surface finish of the materials
Acute exposure to nocturnal train noise induces endothelial dysfunction and pro-thromboinflammatory changes of the plasma proteome in healthy subjects
Nocturnal train noise exposure has been associated with hypertension and myocardial infarction. It remains unclear whether acute nighttime train exposure may induce subclinical atherosclerosis, such as endothelial dysfunction and other functional and/or biochemical changes. Thus, we aimed to expose healthy subjects to nocturnal train noise and to assess endothelial function, changes in plasma protein levels and clinical parameters. In a randomized crossover study, we exposed 70 healthy volunteers to either background or two different simulated train noise scenarios in their homes during three nights. After each night, participants visited the study center for measurement of vascular function and assessment of other biomedical and biochemical parameters. The three nighttime noise scenarios were exposure to either background noise (control), 30 or 60 train noise events (Noise30 or Noise60), with average sound pressure levels of 33, 52 and 54 dB(A), respectively. Flow-mediated dilation (FMD) of the brachial artery was 11.23 ± 4.68% for control, compared to 8.71 ± 3.83% for Noise30 and 8.47 ± 3.73% for Noise60 (p < 0.001 vs. control). Sleep quality was impaired after both Noise30 and Noise60 nights (p < 0.001 vs. control). Targeted proteomic analysis showed substantial changes of plasma proteins after the Noise60 night, mainly centered on redox, pro-thrombotic and proinflammatory pathways. Exposure to simulated nocturnal train noise impaired endothelial function. The proteomic changes point toward a proinflammatory and pro-thrombotic phenotype in response to nocturnal train noise and provide a molecular basis to explain the increased cardiovascular risk observed in epidemiological noise studies
Ab-Externo MicroShunt versus Trabeculectomy in Primary Open-Angle Glaucoma: Two-Year Results from a Randomized, Multicenter Study
PURPOSE: To compare the effectiveness and safety of the MicroShunt (Santen Inc) versus trabeculectomy in patients with primary open-angle glaucoma (POAG). DESIGN: Prospective, randomized, multicenter trial conducted in the United States and Europe. PARTICIPANTS: Adult patients (aged 40-85 years) with mild to severe POAG inadequately controlled on maximum tolerated medical therapy and intraocular pressure (IOP) ≥ 15 mmHg and ≤ 40 mmHg. METHODS: Patients were randomized 3:1 to stand-alone MicroShunt implantation (n = 395) or trabeculectomy (n = 132), both augmented with mitomycin C (MMC) 0.2 mg/ml for 2 minutes. MAIN OUTCOME MEASURES: The primary effectiveness end point was surgical success, defined as ≥ 20% reduction in mean diurnal IOP from baseline with no increase in glaucoma medications. Secondary end points included changes in mean IOP and medication use from baseline and the need for postoperative interventions. RESULTS: At 2 years, the rate of surgical success was lower in the MicroShunt group than in the trabeculectomy group (50.6% vs. 64.4%, P = 0.005). Mean diurnal IOP was reduced from 21.1 ± 4.9 mmHg at baseline to 13.9 ± 3.9 mmHg at 24 months in the MicroShunt group and from 21.1 ± 5.0 mmHg at baseline to 10.7 ± 3.7 mmHg at 24 months in the trabeculectomy group (P < 0.001 compared with baseline in both groups). Mean medication use decreased from 3.1 to 0.9 in the MicroShunt group and from 2.9 to 0.4 in the trabeculectomy group (P < 0.001 compared with baseline in both groups). Adverse events at 2 years were generally similar in the 2 groups, except that hypotony was more common in eyes undergoing trabeculectomy (51.1% vs. 30.9%, P < 0.001). Repositioning or explantation of the implant occurred in 6.8% of MicroShunt patients. The majority of these patients had device removal at the time of subsequent glaucoma surgery. Vision-threatening complications were uncommon in both groups. CONCLUSION: At 2 years, both the MicroShunt and trabeculectomy provided significant reductions in IOP and medication use, with trabeculectomy continuing to have greater surgical success. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article
Strategies and options for increasing and sustaining fisheries and aquaculture production to benefit poorer households in Asia
The last three decades have witnessed dramatic changes in the structure of supply and demand for fish, especially in Asia. This WorldFish research study sponsored by the Asian Development Bank focussed on nine developing countries – Bangladesh, China, India, Indonesia, Malaysia, the Philippines, Sri Lanka, Thailand, and Vietnam, all active players in the transformation of global fish supply and demand. The study, broken into five components and reported here, considered: 1) the profile of key aquaculture technologies and fishing practices; 2) analysis of policies, institutions and support services; 3) socioeconomic profile of major stakeholders in the fisheries sector; 4) projections of fish demand and supply in the nine Asian countries; and 5) formulation of national action plans based on the findings and recommendations of the study
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