Japan Aerospace Exploration Agency

About: Japan Aerospace Exploration Agency is a facility organization based out in Tokyo, Japan. It is known for research contribution in the topics: Galaxy & Telescope. The organization has 4327 authors who have published 12054 publications receiving 208330 citations.

Quantitative analysis of the cutaneous Malassezia microbiota in 770 healthy Japanese by age and gender using a real-time PCR assay.

Abstract: Although the lipophilic yeasts of the genus Malassezia are part of the cutaneous microbiota in healthy individuals, they are also associated with several skin diseases, such as seborrheic dermatitis. However, the effects of age and gender on the Malassezia microbiota have not been completely elucidated. We analyzed the cutaneous Malassezia microbiota of 770 healthy Japanese using the highly accurate real-time PCR with a TaqMan probe to investigate the effects of age and gender on the Malassezia population. The numbers of Malassezia cells increased in males up to 16-18 years of age and in females to 10-12 years old, and subsequently decreased gradually in both genders until senescence. Malassezia restricta overwhelmingly predominated at ages over 16-18 years in males and 23-29 years in females. M. globosa and M. restricta together accounted for more than 70% of Malassezia spp. recovered regardless of gender. The total colonization of Malassezia and the ratio of the two major species change with age and gender in humans.

Model-Based Polarimetric SAR Calibration Method Using Forest and Surface-Scattering Targets

Abstract: This paper proposes a new polarimetric synthetic aperture radar (SAR) (PolSAR) calibration method that applies an incoherent decomposition model to the uncalibrated covariance data measured for the forest and surface and determines the polarimetric distortion matrix (PDM). The Freeman-Durden model is used to express the polarization-dependent signal reflection from and penetration through the forest. Nonlinear equations built for uncalibrated PolSAR data are solved iteratively. This method is applicable to the lower frequency SAR that associates with the polarization-dependent signal penetration through forest canopies. Using the time series Phased-Array-Type L-band SAR (PALSAR) data acquired from the Amazon rainforest for around three years, we confirm that the proposed method succeeds in the PDM estimation and that the calibrated data preserve the polarimetric performance on HH-VV orthogonality, low crosstalks, and ideal polarimetric signature for the corner reflector. This paper also investigates the signal-penetration properties of the forest associated with the L-band SAR.

The dense molecular gas in the circumnuclear disk of ngc 1068

Abstract: We present a 190-307 GHz broadband spectrum obtained with Z-Spec of NGC 1068 with new measurements of molecular rotational transitions. After combining our measurements with those previously published and considering the specific geometry of this Seyfert 2 galaxy, we conduct a multi-species Bayesian likelihood analysis of the density, temperature, and relative molecular abundances of HCN, HNC, CS, and HCO+. We find that these molecules trace warm (T>100 K) gas of H_2 number densities 10^(4.2)-10^(4.9) cm^(–3). Our models also place strong constraints on the column densities and relative abundances of these molecules, as well as on the total mass in the circumnuclear disk. Using the uniform calibration afforded by the broad Z-Spec bandpass, we compare our line ratios to X-ray-dominated region (XDR) and photon-dominated region models. The majority of our line ratios are consistent with the XDR models at the densities indicated by the likelihood analysis, lending substantial support to the emerging interpretation that the energetics in the circumnuclear disk of NGC 1068 are dominated by accretion onto an active galactic nucleus.

Toward an operational anthropogenic CO2 emissions monitoring and verification support capacity

Abstract: Under the Paris Agreement (PA), progress of emission reduction efforts is tracked on the basis of regular updates to national greenhouse gas (GHG) inventories, referred to as bottom-up estimates. However, only top-down atmospheric measurements can provide observation-based evidence of emission trends. Today, there is no internationally agreed, operational capacity to monitor anthropogenic GHG emission trends using atmospheric measurements to complement national bottom-up inventories. The European Commission (EC), the European Space Agency, the European Centre for Medium-Range Weather Forecasts, the European Organisation for the Exploitation of Meteorological Satellites, and international experts are joining forces to develop such an operational capacity for monitoring anthropogenic CO2 emissions as a new CO2 service under the EC's Copernicus program. Design studies have been used to translate identified needs into defined requirements and functionalities of this anthropogenic CO2 emissions Monitoring and Verification Support (CO2MVS) capacity. It adopts a holistic view and includes components such as atmospheric spaceborne and in situ measurements, bottom-up CO2 emission maps, improved modeling of the carbon cycle, an operational data-assimilation system integrating top-down and bottom-up information, and a policy-relevant decision support tool. The CO2MVS capacity with operational capabilities by 2026 is expected to visualize regular updates of global CO2 emissions, likely at 0.05° x 0.05°. This will complement the PA's enhanced transparency framework, providing actionable information on anthropogenic CO2 emissions that are the main driver of climate change. This information will be available to all stakeholders, including governments and citizens, allowing them to reflect on trends and effectiveness of reduction measures. The new EC gave the green light to pass the CO2MVS from exploratory to implementing phase.

Observation of sea-ice thickness in the sea of Okhotsk by using dual-frequency and fully polarimetric airborne SAR (pi-SAR) data

Abstract: To investigate the possibilities of using dual-frequency, multipolarization synthetic aperture radar (SAR) data to monitor sea ice, we derived the relationship between various polarization characteristics and the physical parameters of sea ice. We discuss the frequency and polarization characteristics of the backscattering coefficients of sea ice and then characterize its thickness by comparing the corresponding backscattering coefficient for each polarization with the physical parameters of the ice. We first propose a methodology for classifying sea-ice types by using a polarimetric decomposition technique, before comparing an estimation of the sea-ice thickness with the corresponding dual-frequency, multipolarization SAR data. We utilized the backscattering ratio to estimate the thickness of the sea ice. This ratio canceled the effect of roughness on the backscattering. The method was validated using Pi-SAR (polarimetric and interferometric airborne SAR) observation data obtained at ground-truth sites.