265 research outputs found

    Universal dark halo scaling relation for the dwarf spheroidal satellites

    Full text link
    Motivated by a recently found interesting property of the dark halo surface density within a radius, rmaxr_{\rm max}, giving the maximum circular velocity, VmaxV_{\rm max}, we investigate it for dark halos of the Milky Way's and Andromeda's dwarf satellites based on cosmological simulations. We select and analyze the simulated subhalos associated with Milky Way-sized dark halos and find that the values of their surface densities, ΣVmax\Sigma_{V_{\rm max}}, are in good agreement with those for the observed dwarf spheroidal satellites even without employing any fitting procedures. This implies that this surface density would not be largely affected by any baryonic feedbacks and thus universal. Moreover, all subhalos on the small scales of dwarf satellites are expected to obey the relation ΣVmaxVmax\Sigma_{V_{\rm max}}\propto V_{\rm max}, irrespective of differences in their orbital evolutions, host halo properties, and observed redshifts. Therefore, we find that the universal scaling relation for dark halos on dwarf galaxy mass scales surely exists and provides us important clues to understanding fundamental properties of dark halos. We also investigate orbital and dynamical evolutions of subhalos to understand the origin of this universal dark halo relation and find that most of subhalos evolve generally along the rmaxVmaxr_{\rm max}\propto V_{\rm max} sequence, even though these subhalos have undergone different histories of mass assembly and tidal stripping. This sequence, therefore, should be the key feature to understand the nature of the universality of ΣVmax\Sigma_{V_{\rm max}}.Comment: 12 pages, 5 figures and 3 tables, submitted to Ap

    Genome sequence analysis of new plum pox virus isolates from Japan

    Get PDF
    Objective To find mutations that may have recently occurred in Plum pox virus (PPV), we collected six PPV-infected plum/peach trees from the western part of Japan and one from the eastern part. After sequencing the full-length PPV genomic RNAs, we compared the amino acid sequences with representative isolates of each PPV strain. Results All new isolates were found to belong to the PPV-D strain: the six isolates collected from western Japan were identified as the West-Japan strain while the one collected from eastern Japan as the East-Japan strain. Amino acid sequence analysis of these seven isolates suggested that the 1407th and 1529th amino acid residues are characteristic of the West-Japan and the East-Japan strains, respectively. Comparing them with the corresponding amino acid residues of the 47 non-Japanese PPV-D isolates revealed that these amino acid residues are undoubtedly unique. A further examination of the relevant amino acid residues of the other 210 PPV-D isolates collected in Japan generated a new hypothesis regarding the invasion route from overseas and the subsequent diffusion route within Japan: a PPV-D strain might have invaded the western part of Japan from overseas and spread throughout Japan

    Development of a method to rapidly assess resistance/susceptibility of Micro-Tom tomatoes to Tomato yellow leaf curl virus via agroinoculation of cotyledons

    Get PDF
    Objective: Tomato yellow leaf curl virus (TYLCV) is one of the pathogens severely damaging tomato crops. Therefore, methods to treat or prevent TYLCV infection need to be developed. For this purpose, a method to conveniently and quickly assess infection of tomatoes by TYLCV is desired. In the present study, we established a quick method to evaluate TYLCV infection using cotyledons of Micro-Tom, a miniature tomato cultivar. Results: First, we constructed a binary plasmid harboring 1.5 copies of the TYLCV genome and transformed Agrobacterium with the plasmid. By injecting agroinoculum from the resulting transformant into the branches of Micro-Tom, we confirmed the susceptibility of Micro-Tom to TYLCV. To shorten the evaluation process of TYLCV infection further, we agroinoculated cotyledons of Micro-Tom 10 days after sowing seeds. We consistently observed typical symptoms of TYLCV infection on true leaves 10 days after agroinoculation. Molecular analysis detected TYLCV progeny DNA in all leaves demonstrating symptoms 6 days after agroinoculation. Therefore, our new protocol enabled assessment of TYLCV infection within 20 days after sowing seeds. Thus, agroinoculation of Micro-Tom cotyledons will accelerate the process of screening TYLCV-resistant Micro-Toms and enable screening of larger numbers of plants more quickly, contributing to the development of TYLCV-resistant tomatoes

    A Feasibility Study on the Simultaneous Sensing of Turbidity and Chlorophyll a Concentration Using a Simple Optical Measurement Method

    Get PDF
    We have been developing a wireless sensor network system to monitor the quality of lake water in real time. It consists of a sensor module and a system module, which includes communication and power modules. We have focused on pH, turbidity and chlorophyll a concentration as the criteria for qualifying lake water quality. These parameters will be detected by a microfluidic device based sensor module embedded in the wireless sensor network system. In order to detect the turbidity and the chlorophyll a concentration simultaneously, we propose a simple optical measurement method using LED and photodiode in this paper. Before integrating a turbidity and chlorophyll a concentration sensor into the microfluidic device based pH sensor, we performed feasibility studies such as confirmation of the working principle and experiments using environmental water samples. As a result, we successfully verified our simultaneous sensing method by using a simple optical setup of the turbidity and the chlorophyll a concentration

    MACULAR BLOOD FLOW CHANGES IN BRANCH RETINAL VEIN OCCLUSION EXAMINED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY VARIABLE INTERSCAN TIME ANALYSIS

    Get PDF
    Purpose: To examine the relationship between changes in retinal blood flow and the recurrence of macular edema in eyes with branch retinal vein occlusion. Methods: This observational study included 32 eyes in 32 patients (18 men and 14 women) with branch retinal vein occlusion who visited the Department of Ophthalmology at Kyoto University Hospital (February 2021–November 2021). At the time of inclusion in the study, each patient underwent optical coherence tomography angiography on a macular area measuring 4 × 4 mm2. For variable interscan time analysis, different interscan times were set at 7.6 (IST7.6) and 20.6 ms (IST20.6) for the optical coherence tomography angiography. The parafoveal vessel densities were measured sectorally at IST7.6 and IST20.6, and their relationship with the longitudinal changes evident in the retinal thicknesses during the variable interscan time analysis examination and 2 months later was evaluated. Results: The parafoveal vessel densities in the affected sector was significantly greater at IST20.6 than at IST7.6 (P = 0.011). At 2 months after the variable interscan time analysis examination, 6 patients (19%) showed recurrence of macular edema involving the fovea. The difference in the parafoveal vessel densities (IST20.6 − IST7.6) in the affected sector was significantly associated with longitudinal retinal thickening in the corresponding parafovea (P = 0.020) and fovea (P = 0.014). Conclusion: In eyes with branch retinal vein occlusion, optical coherence tomography angiography variable interscan time analysis facilitated the detection of retinal blood flow changes that might be predictive for the recurrence of macular edema

    Clinically Significant Nonperfusion Areas on Widefield OCT Angiography in Diabetic Retinopathy

    Get PDF
    [Purpose] To investigate the distribution of clinically significant nonperfusion areas (NPAs) on widefield OCT angiography (OCTA) images in patients with diabetes. [Design] Prospective, cross-sectional, observational study. [Participants] One hundred and forty-four eyes of 114 patients with diabetes. [Methods] Nominal 20 × 23 mm OCTA images were obtained using a swept-source OCTA device (Xephilio OCT-S1), followed by the creation of en face images 20-mm (1614 pixels) in diameter centering on the fovea. The nonperfusion squares (NPSs) were defined as the 10 × 10 pixel squares without retinal vessels, and the ratio of eyes with the NPSs to all eyes in each square was referred to as the NPS ratio. The areas with probabilistic differences (APD) for proliferative diabetic retinopathy (PDR) and nonproliferative diabetic retinopathy (NPDR) (APD[PDR] and APD[NPDR]) were defined as sets of squares with higher NPS ratios in eyes with PDR and NPDR, respectively. The P ratio (NPSs within APD[PDR] but not APD[NPDR]/all NPSs) was also calculated. [Main Outcome Measures] The probabilistic distribution of the NPSs and the association with diabetic retinopathy (DR) severity. [Results] The NPSs developed randomly in eyes with mild and moderate NPDR and were more prevalent in the extramacular areas and the temporal quadrant in eyes with severe NPDR and PDR. The APD(PDR) was distributed mainly in the extramacular areas, sparing the areas around the vascular arcades and radially peripapillary capillaries. The APD(PDR) contained retinal neovascularization more frequently than the non-APD(PDR) (P = 0.023). The P ratio was higher in eyes with PDR than in those with NPDR (P < 0.001). The multivariate analysis designated the P ratio (odds ratio, 8.293 × 107; 95% confidence interval, 6.529 × 102–1.053 × 1013; P = 0.002) and the total NPSs (odds ratio, 1.002; 95% confidence interval, 1.001–1.003; P < 0.001) as independent risk factors of PDR. Most eyes with NPDR and 4-2-1 rule findings of DR severity had higher P ratios but not necessarily greater NPS numbers. [Conclusions] The APD(PDR) is uniquely distributed on widefield OCTA images, and the NPA location patterns are associated with DR severity, independent of the entire area of NPAs. [Financial Disclosure(s)] Proprietary or commercial disclosure may be found after the references
    corecore