131 research outputs found

    Atmospheric Thermodynamic Profiling through the Use of a Micro-Pulse Raman Lidar System: Introducing the Compact Raman Lidar MARCO

    Get PDF
    It was for a long time believed that lidar systems based on the use of high-repetition micro-pulse lasers could be effectively used to only stimulate atmospheric elastic backscatter echoes, and thus were only exploited in elastic backscatter lidar systems. Their application to stimulate rotational and roto-vibrational Raman echoes, and consequently, their exploitation in atmospheric thermodynamic profiling, was considered not feasible based on the technical specifications possessed by these laser sources until a few years ago. However, recent technological advances in the design and development of micro-pulse lasers, presently achieving high UV average powers (1–5 W) and small divergences (0.3–0.5 mrad), in combination with the use of large aperture telescopes (0.3–0.4 m diameter primary mirrors), allow one to presently develop micro-pulse laser-based Raman lidars capable of measuring the vertical profiles of atmospheric thermodynamic parameters, namely water vapor and temperature, both in the daytime and night-time. This paper is aimed at demonstrating the feasibility of these measurements and at illustrating and discussing the high achievable performance level, with a specific focus on water vapor profile measurements. The technical solutions identified in the design of the lidar system and their technological implementation within the experimental setup of the lidar prototype are also carefully illustrated and discussed

    Supernova 1987A light curve

    Get PDF
    V and B light curves for supernova 1987A are here presented and discussed. Just after the outburst in February 23.120 (UT), the brightening was very fast: approximately 6.2 magnitudes in only 7 hours and 41 minutes; subsequently, changes in brightness slowed down and the SN stayed as long as 130 days brighter than magnitude mᵥ=4.4 (or m_b=5.). The brightening rate at the beginning of the event and the time spent around maximum light are somewhat larger than usual. At maximum brightness SN 1987A reached Mᵥₘₐₓ=-16.1, and M_bmax=-14.7. Typical values for a type II SN being Mᵥₘₐₓ ≃ M_bmax = -17.60, the conclusion is arrived at that SN 1987A was fainter than usual for objects of this class. A comparison with other known supernovae is made. This paper will be published in full elsewhere.Asociación Argentina de Astronomí

    The Merging System Am 2049-691

    Get PDF
    Spectroscopic and photometric observations of the peculiar object AM 2049-691 are presented here. Its systemic velocity is V(GSR) = (10956 +-30) km/s, and the derived distance (H(0) = 75 km/s/Mpc) results 146 Mpc. A bridge is observed between two very distinct nuclei whose separation is about 10 kpc, as well as two tails that emerge from the extremes SW and NE of the main body and extend up to 41 and 58 kpc respectively. The spectral characteristics of the all observed zones are typical of H II regions of low excitation. The internal reddening is quit high, particularly in the NE nucleus. All the derived equivalent widths of the H(alpha)+[N II] lines indicate enhanced star formation compared with isolated galaxies, specially in the NE nucleus; the equivalent width corresponding to the integrated spectrum reflects starburst activity in the whole object, and is compatible with a merger of two disk galaxies. All the observed characteristics of AM 2049-691 indicate it is a merger, where a overabundance of nitrogen is detected in one of the nuclei, which has the most evolved population and would be the most massive one. The detected total IR emission is not very high. The integrated total color B - V corresponds to a Sc-Scd galaxy and its average integrated population is about F7 type. Indicative B - V colors of the nuclei, corrected for internal absorption, are in agreement with the spectroscopic results. The central radial velocity dispersions at the nuclei suggest that the most massive galaxy would be the progenitor of the SW component. The observed radial velocity curve shows the presence of two subsystems, each one associated with a different nucleus.Comment: 5 pages, 4 figure

    Magnetic resonance of rectal cancer response to therapy: an Image quality comparison between 3.0 and 1.5 Tesla

    Get PDF
    Purpose. To evaluate signal intensity (SI) differences between 3.0 T and 1.5 T on T2-weighted (T2w), diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC) in rectal cancer pre-, during, and postneoadjuvant chemoradiotherapy (CRT). Materials and Methods. 22 patients with locally advanced rectal cancer were prospectively enrolled. All patients underwent T2w, DWI, and ADC pre-, during, and post-CRT on both 3.0 T MRI and 1.5 T MRI. A radiologist drew regions of interest (ROIs) of the tumor and obturator internus muscle on the selected slice to evaluate SI and relative SI (rSI). Additionally, a subanalysis evaluating the SI before and after-CRT (ΔSI pre-post) in complete responder patients (CR) and nonresponder patients (NR) on T2w, DWI, and ADC was performed. Results. Significant differences were observed for T2w and DWI on 3.0 T MRI compared to 1.5 T MRI pre-, during, and post-CRT (all P<0.001), whereas no significant differences were reported for ADC among all controls (all P>0.05). rSI showed no significant differences in all the examinations for all sequences (all P>0.05). ΔSI showed significant differences between 3.0 T and 1.5 T MRI for DWI-ΔSI in CR and NR (188.39±166.90 vs. 30.45±21.73 and 169.70±121.87 vs. 22.00±31.29, respectively, all P 0.02) and ADC-ΔSI for CR (-0.58±0.27 vs. -0.21±0.24P value 0.02), while no significant differences were observed for ADC-ΔSI in NR and both CR and NR for T2w-ΔSI. Conclusion. T2w-SI and DWI-SI showed significant differences for 3.0 T compared to 1.5 T in all three controls, while ADCSI showed no significant differences in all three controls on both field strengths. rSI was comparable for 3.0 T and 1.5 T MRI in rectal cancer patients; therefore, rectal cancer patients can be assessed both at 3.0 T MRI and 1.5 T MRI. However, a significant DWI-ΔSI and ADC-ΔSI on 3.0 T in CR might be interpreted as a better visual assessment in discriminating response to therapy compared to 1.5 T. Further investigations should be performed to confirm future possible clinical application

    Geospatial Resolution of Human and Bacterial Diversity with City-Scale Metagenomics

    Get PDF
    The panoply of microorganisms and other species present in our environment influence human health and disease, especially in cities, but have not been profiled with metagenomics at a city-wide scale. We sequenced DNA from surfaces across the entire New York City (NYC) subway system, the Gowanus Canal, and public parks. Nearly half of the DNA (48%) does not match any known organism; identified organisms spanned 1,688 bacterial, viral, archaeal, and eukaryotic taxa, which were enriched for harmless genera associated with skin (e.g., Acinetobacter). Predicted ancestry of human DNA left on subway surfaces can recapitulate U.S. Census demographic data, and bacterial signatures can reveal a station’s history, such as marine-associated bacteria in a hurricane-flooded station. Some evidence of pathogens was found (Bacillus anthracis), but a lack of reported cases in NYC suggests that the pathogens represent a normal, urban microbiome. This baseline metagenomic map of NYC could help long-term disease surveillance, bioterrorism threat mitigation, and health management in the built environment of citie

    Impact of Vutrisiran on Quality of Life and Physical Function in Patients with Hereditary Transthyretin-Mediated Amyloidosis with Polyneuropathy

    Get PDF
    INTRODUCTION: Hereditary transthyretin (ATTRv; v for variant) amyloidosis, also known as hATTR amyloidosis, is a progressive and fatal disease associated with rapid deterioration of physical function and patients' quality of life (QOL). Vutrisiran, a subcutaneously administered RNA interference (RNAi) therapeutic that reduces hepatic production of transthyretin, was assessed in patients with ATTRv amyloidosis with polyneuropathy in the pivotal HELIOS-A study. METHODS: The phase 3 open-label HELIOS-A study investigated the efficacy and safety of vutrisiran in patients with ATTRv amyloidosis with polyneuropathy, compared with an external placebo group from the APOLLO study of the RNAi therapeutic patisiran. Measures of QOL and physical function were assessed. RESULTS: At month 18, vutrisiran improved Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) total score (least squares mean difference [LSMD] in change from baseline [CFB]: –21.0; p = 1.84 × 10–10) and Norfolk QOL-DN domain scores, compared with external placebo. This benefit relative to external placebo was evident across all baseline polyneuropathy disability (PND) scores and most pronounced in patients with baseline PND scores I–II. Compared with external placebo, vutrisiran also demonstrated benefit in EuroQoL-Visual Analog Scale (EQ-VAS) score (LSMD in CFB: 13.7; nominal p = 2.21 × 10–7), 10-m walk test (LSMD in CFB: 0.239 m/s; p = 1.21 × 10–7), Rasch-built Overall Disability Score (LSMD in CFB: 8.4; p = 3.54 × 10–15), and modified body mass index (mBMI) (LSMD in CFB: 140.7; p = 4.16 × 10–15) at month 18. Overall, Norfolk QOL-DN, EQ-VAS, and mBMI improved from pretreatment baseline with vutrisiran, whereas all measures worsened from baseline in the external placebo group. At month 18, Karnofsky Performance Status was stable/improved from baseline in 58.2/13.1% with vutrisiran versus 34.7/8.1% with external placebo. CONCLUSION: Vutrisiran treatment provided significant clinical benefits in multiple measures of QOL and physical function in patients with ATTRv amyloidosis with polyneuropathy. Benefits were most pronounced in patients with earlier-stage disease, highlighting the importance of early diagnosis and treatment
    corecore