421 research outputs found
Mapping Earth Analogs from Photometric Variability: Spin-Orbit Tomography for Planets in Inclined Orbits
Aiming at obtaining detailed information of surface environment of Earth
analogs, Kawahara & Fujii (2011) proposed an inversion technique of annual
scattered light curves named the spin-orbit tomography (SOT), which enables one
to sketch a two-dimensional albedo map from annual variation of the
disk-integrated scattered light, and demonstrated the method with a planet in a
face-on orbit. We extend it to be applicable to general geometric
configurations, including low-obliquity planets like the Earth in inclined
orbits. We simulate light curves of the Earth in an inclined orbit in three
photometric bands (0.4-0.5um, 0.6-0.7um, and 0.8-0.9um) and show that the
distribution of clouds, snow, and continents is retrieved with the aid of the
SOT. We also demonstrate the SOT by applying it to an upright Earth, a tidally
locked Earth, and Earth analogs with ancient continental configurations. The
inversion is model independent in the sense that we do not assume specific
albedo models when mapping the surface, and hence applicable in principle to
any kind of inhomogeneity. This method can potentially serve as a unique tool
to investigate the exohabitats/exoclimes of Earth analogs.Comment: 15 pages, 14 figures, 2 tables; published in The Astrophysical
Journa
Global Mapping of Earth-like Exoplanets from Scattered Light Curves
Scattered lights from terrestrial exoplanets provide valuable information
about the planetary surface. Applying the surface reconstruction method
proposed by Fujii et al. (2010) to both diurnal and annual variations of the
scattered light, we develop a reconstruction method of land distribution with
both longitudinal and latitudinal resolutions. We find that one can recover a
global map of an idealized Earth-like planet on the following assumptions: 1)
cloudless, 2) a face-on circular orbit, 3) known surface types and their
reflectance spectra 4) no atmospheric absorption, 5) known rotation rate 6)
static map, and 7) no moon. Using the dependence of light curves on the
planetary obliquity, we also show that the obliquity can be measured by
adopting the chi-square minimization or the extended information criterion. We
demonstrate a feasibility of our methodology by applying it to a multi-band
photometry of a cloudless model Earth with future space missions such as the
occulting ozone observatory (O3). We conclude that future space missions can
estimate both the surface distribution and the obliquity at least for cloudless
Earth-like planets within 5 pc.Comment: 20 pages, 19 figures, accepted for publication in Ap
Perilla Extract improves gastrointestinal discomfort in a randomized placebo controlled double blind human pilot study
BACKGROUND: Gastrointestinal (GI) discomfort, e.g. bloating or rumbling, is a common symptom in otherwise healthy adults. Approximately 20% of the population, particularly women suffer from gastrointestinal discomfort and this affects quality of life. Recent studies discovered a link between the body and mind, called the gut-brain axis. Psychosocial factors, such as e.g. daily stress may cause altered gut physiology leading to ileum contractions and consequently gastrointestinal symptoms. In vitro and ex vivo studies clearly showed that a Perilla frutescens extract combines prokinetic, antispasmodic and anti-inflammatory effects. The aim of the intervention was to investigate the effects of the proprietary Perilla extract on GI discomfort in healthy subjects with gastrointestinal discomfort and reduced bowel movements in comparison to a placebo product. METHODS: The pilot study was performed according to a double-blind, randomized, placebo-controlled parallel design. Fifty healthy subjects with gastrointestinal discomfort and reduced bowel movements, 30-70 years, documented their GI symptoms, stool frequency and consistency daily during a 2-week run-in phase and a 4-week intervention phase with Perilla frutescens extract or placebo. GI symptoms were assessed on a 5-point scale daily and average scores over 14 days intervals were calculated. RESULTS: All GI symptoms were significantly improved over time by Perilla frutescens extract during the intervention phase (bloating: -0.44 ± 0.56, p = 0.0003; passage of gas: -0.30 ± 0.66, p = 0.0264; GI rumbling: -0.55 ± 0.87, p = 0.0014; feeling of fullness: -0.36 ± 0.72, p = 0.0152; abdominal discomfort: -0.54 ± 0.75, p = 0.004), whereas in the placebo group only abdominal discomfort was significantly improved (-0.31 ± 0.55, p = 0.0345). In the subgroup of women results were strengthened and a subscore out of bloating and abdominal discomfort was significantly improved against placebo (95%CI 0.003 to 0.77; p = 0.048). CONCLUSION: The demonstrated effects of Perilla frutescens extract to improve GI complaints offer very promising results, taking into consideration the challenging set up of a nutritional human study with healthy subjects and in the area of digestive health, which is known for high placebo effects. TRIAL REGISTRATION NUMBER: NCT01931930 at ClinicalTrials.gov, Registration date 23(rd) August 2013
Can Ground-based Telescopes Detect The Oxygen 1.27 Micron Absorption Feature as a Biomarker in Exoplanets ?
The oxygen absorption line imprinted in the scattered light from the
Earth-like planets has been considered the most promising metabolic biomarker
of the exo-life. We examine the feasibility of the detection of the 1.27 micron
oxygen band from habitable exoplanets, in particular, around late- type stars
observed with a future instrument on a 30 m class ground-based telescope. We
analyzed the night airglow around 1.27 micron with IRCS/echelle spectrometer on
Subaru and found that the strong telluric emission from atmospheric oxygen
molecules declines by an order of magnitude by midnight. By compiling nearby
star catalogs combined with the sky background model, we estimate the
detectability of the oxygen absorption band from an Earth twin, if it exists,
around nearby stars. We find that the most dominant source of photon noise for
the oxygen 1.27 micron band detection comes from the night airglow if the
contribution of the stellar PSF halo is suppressed enough to detect the planet.
We conclude that the future detectors for which the detection contrast is
limited by photon noise can detect the oxygen 1.27 micron absorption band of
the Earth twins for ~50 candidates of the late type star. This paper
demonstrates the importance of deploying small inner working angle efficient
coronagraph and extreme adaptive optics on extremely large telescopes, and
clearly shows that doing so will enable study of potentially habitable planets.Comment: 11 pages, 9 figures, accepted for publication in The Astrophysical
Journa
C. elegans PlexinA PLX-1 mediates a cell contact-dependent stop signal in vulval precursor cells
AbstractPLX-1 is a PlexinA transmembrane protein in Caenorhabditis elegans, and the transmembrane-type semaphorin, SMP-1, is a ligand for PLX-1. The SMP-1/PLX-1 system has been shown to be necessary for proper epidermal morphogenesis in the male tail and seam cells. Here, we show that the SMP-1/PLX-1 system also regulates vulval morphogenesis. In plx-1 and smp-1 mutants, hermaphrodites sometimes exhibit a protruding vulva or multiple vulva-like protrusions. Throughout the vulval development of plx-1 and smp-1 mutants, the arrangement of vulval cells is often disrupted. In the initial step of vulval morphogenesis, vulval precursor cells (VPCs) are generated normally but are subsequently arranged abnormally in mutants. Continuous observation revealed that plx-1 VPC fails to terminate longitudinal extension after making contact with neighbor VPCs. The arrangement defects of VPCs in plx-1 and smp-1 mutants are rescued by expressing the respective cDNA in VPCs. plx-1::egfp and smp-1::egfp transgenes are both expressed in all vulval cells, including VPCs, throughout vulval development. We propose that the SMP-1/PLX-1 system is responsible for a cell contact-mediated stop signal for VPC extension. Analyses using cell fate-specific markers showed that the arrangement defects of VPCs also affect cell fate specification and cell lineages, but in a relatively small fraction of plx-1 mutants
A case of pulmonary arterial hypertension complicated by anti-neutrophil cytoplasmic antibody-associated vasculitis and systemic sclerosis
Pulmonary arterial hypertension (PAH) is a rare complication of ANCA-associated vasculitis (AAV). We report a 37-year-old man with PAH complicated by both AAV and SSc who presented with dyspnea, cardiac enlargement, positive myeloperoxidase (MPO)-ANCA, anti-centromere antibodies, proteinuria, and urinary casts. Elevated pulmonary arterial pressure (58/22/34 mmHg) and low PAWP (2 mmHg) were confirmed by right heart catheterization. Treatment with glucocorticoids (GC) decreased urinary protein and serum MPO-ANCA; however, PAH did not respond to GC. Therefore, a combination of beraprost, bosentan, and tadalafil was needed. The differences in responses to GC suggest that the pathophysiology of nephropathy is different from that of PAH. We considered that nephropathy was associated with AAV but that PAH was associated with SSc in the present case. We discuss the pathophysiology and treatment response of PAH complicated by AAV, referring to nine past cases
Interaction between dye and zinc in the dye-dispersing ZnO films prepared by a wet process
Dye-dispersing ZnO precursor gel films were prepared on indium tin oxide electrodes from a zinc acetate solution containing eosin Y by dip-coating, steam treatment, and then heating at a low temperature. The electronic interaction between the dye and zinc in the dye-dispersing gel films were investigated by spectroscopic and electrochemical measurements. A photocurrent was observed in the dye-dispersing gel electrodes before the steam treatment. The photocurrent value increased by the steam treatment and heating due to crystallization of the gel and removal of organic impurities. The dye molecules existed between the interlayers of the layered zinc hydroxide coexisting with the ZnO. The photoexcited electron in the dye should be injected into the ZnO conduction band via the layered zinc hydroxide. The value increased with an increase in the dye content even though the ZnO crystallinity decreased. The dye-zinc interaction, i.e., the complex formation and photoinduced electron injection, played an important role in the electron transport and photoelectric conversion.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 41(9):6559-6574 (2015)journal articl
Acoustoelastic Axial Stress Measurement of Short Bolts with Longitudinal and Transverse Waves
The bolts used for automobiles are relatively small compared with those used in power plants, steel bridges and frames. The precise control of the fastening force is required for important parts. The force measurement by torque wrenches is, however, unreliable because it does measure the frictional torque caused by the axial force not but axial force itself. Therefore direct measurement of the axial force in those bolts is required. The conventional ultrasonic bolt gages are not applicable for these short bolts because the bolt length uniformly stressed is small compared with the total length. An ultrasonic resonance method [1] is useful for axial stress measurement of these bolts, however, it requires long measurement time because of frequency sweep and both measurements in stressed and unstressed states.</p
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