Time domain astronomy is one of the prosperous sub-divisions recent years, which explores the properties and physical origins such as variable and transient sources by observing the spatial and temporal variations of various types of celestial bodies in the universe. Observations of variable and transient sources are an important part of the field of time-domain astronomy, and modern astronomical observations are commonly carried out using advanced large-field telescopes for long-term uninterrupted observations. This paper survey relationship high-energy X-ray, Gamma-ray and bursts with the variable source, refer to the binary star and black hole. Then multi-bands electromagnetic wave is discussed because that is relative to detection of the variable source and instrument sensor of mission in practice. Moreover, the paper surveys the relative ground-based and space-based telescopes and missions recent years. Lastly the new approach and strategy appear the latest mission are discussed.
Abstract For several years we have been running an “astro-animation” class (AstroAnimation.org) at the Maryland Institute College of Art (MICA) in Baltimore where students work in tandem with research scientists from NASA Goddard and elsewhere to create animations. These combine results of cutting-edge research with an artist’s eye to create novel presentations of scientific results. The animations have been used for scientific outreach and educational purposes, including presentations at museums, and art, STEAM, and science fiction festivals. Astronomy has broad public interest with a “wow” factor related to black holes, dark matter, life in the universe and more. Animation is an ideal medium since it combines creative approaches, is highly popular, and the films produced are readily available for distribution.
Richard Fenner, Emily O’Donnell, Sangaralingam Ahilan
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Preliminary results of the UK Urban Flood Resilience research consortium are presented and discussed, with the work being conducted against a background of future uncertainties with respect to changing climate and increasing urbanization. Adopting a whole systems approach, key themes include developing adaptive approaches for flexible engineering design of coupled grey and blue-green flood management assets; exploiting the resource potential of urban stormwater through rainwater harvesting, urban metabolism modelling and interoperability; and investigating the interactions between planners, developers, engineers and communities at multiple scales in managing flood risk. The work is producing new modelling tools and an extensive evidence base to support the case for multifunctional infrastructure that delivers multiple, environmental, societal and economic benefits, while enhancing urban flood resilience by bringing stormwater management and green infrastructure together.
The raising worldwide prevalence of Type 1 and Type 2 diabetes mellitus (T1DM and T2DM) solicits the derivation of in vitro methods yielding mature and fully functional β-cells to be used in regenerative medicine. Several protocols to differentiate human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) into human pancreatic β-like cells have recently been developed. These methods, coupled with a bioengineering approach using biocompatible encapsulating devices, have recently led to experimental clinical trials showing great promises to ultimately end the battle of diabetic patients for managing hyperglycemia. However, in vitro differentiation protocols face the challenge of achieving homogenous population of mono-hormonal insulin-secreting mature β-cells. Major epigenetic events such as DNA methylation, post-translational modification of histones and non-coding RNAs expression, orchestrate physiological endocrine pancreas specification into α-, β-, γ-, and δ-cells, both in vivo and in vitro. The dysregulation of such epigenetic processes is associated to multiple pancreatic disorders including diabetes. Understanding the epigenomic and transcriptomic landscape underlying endocrine pancreas development could, therefore, improve in vitro differentiation methods. In this review, we summarize the most effective protocols for in vitro differentiation of hESCs/hiPSCs toward pancreatic β-cells and we discuss the current limitations in the derivation of functional glucose-responsive, insulin-releasing β-cells. Moreover, we focus on the main transcriptional and epigenetic events leading to pancreatic specification and on the applicative potential of novel epigenetic drugs for the establishment of innovative pharmacological therapeutic approaches.
Abstract We have revisited the ultraviolet and optical spectra of the blue horizontal branch star Feige 86. The new analysis finds the star cooler and more compact than previously determined. The IUE spectrum of Feige 86 holds numerous unidentified spectral lines of heavy metals, indicating efficient atomic diffusion in the atmosphere. Because diffusion plays a key role in the atmospheres of hot subdwarfs as well, it is indispensable to a better understanding of subdwarf pulsations and evolution. Feige 86 looks like an ideal target to confront diffusion theory with observations and test spectroscopic techniques. Therefore, to advance our general understanding of diffusion in stellar atmospheres we urge for new ultraviolet spectroscopy of Feige 86 at the highest possible resolution with HST/STIS.
This article is the second of a series of articles aiming at proving the feasibility of the forecast of all the most relevant classical atmospherical parameters for astronomical applications (wind speed and direction, temperature, relative humidity) and the optical turbulence (C N and the derived astro-climatic parameters like seeing ε, isoplanatic angle θ0, wavefront coherence time τ0...). This study is done in the framework of the MOSE project, and focused above the two ESO ground-bases sites of Cerro Paranal and Cerro Armazones. In this paper we present the results related to the Meso-Nh model ability in reconstructing the surface layer atmospherical parameters (wind speed intensity, wind direction and absolute temperature, [0-30] m a. g. l.). The model reconstruction of all the atmospherical parameters in the surface layer is very satisfactory. For the temperature, at all levels, the RMSE (Root Mean Square Error) is inferior to 1◦C. For the wind speed, it is ∼2 m·s, and for the wind direction, it is in the range [38-46◦], at all levels, that corresponds to a RMSErelative in a range [21-26%]. If a filter is applied for the wind direction (the winds inferior to 3 m·s are discarded from the computations), the wind direction RMSE is in the range [3041◦], i.e. a RMSErelative in the range [17-23%]. The model operational forecast of the surface layer atmospherical parameters is suitable for different applications, among others: thermalization of the dome using the reconstructed temperature, hours in advance, of the beginning the night; knowing in advance the main direction which the strong winds will come from during the night could allow the astronomer to anticipate the occurrence of a good/bad seeing night, and plan the observations accordingly; preventing adaptive secondary mirrors shake generated by the wind speed.
Upcoming high spectral resolution telescopes, particularly Astro-H, are expected to finally deliver firm quantitative constraints on turbulence in the intra-cluster medium (ICM). We develop a new spectral analysis technique which exploits not just the line width but the entire line shape, and show how the excellent spectral resolution of Astro-H can overcome its relatively poor spatial resolution in making detailed inferences about the velocity field. The spectrum is decomposed into distinct components, which can be quantitatively analysed using Gaussian mixture models. For instance, bulk flows and sloshing produce components with offset means, while partial volume-filling turbulence from the active galactic nucleus (AGN) or galaxy stirring leads to components with different widths. The offset between components allows us to measure gas bulk motions and separate them from small-scale turbulence, while component fractions and widths constrain the emission weighted volume and turbulent energy density in each component. We apply mixture modelling to a series of analytic toy models as well as numerical simulations of clusters with cold fronts and AGN feedback, respectively. From Markov chain Monte Carlo and Fisher's matrix estimates which include line blending and continuum contamination, we show that the mixture parameters can be accurately constrained with Astro-H spectra: at an ∼10 per cent level when components differ significantly in width, and an ∼1 per cent level when they differ significantly in the mean value. We also study error scalings and use information criteria to determine when a mixture model is preferred. Mixture modelling of spectra is a powerful technique which is potentially applicable to other astrophysical scenarios.
Abstract We report on the performance of an analog application-specific integrated circuit (ASIC) developed aiming for the front-end electronics of the X-ray CCD camera system onboard the next X-ray astronomical satellite, ASTRO-H. It has four identical channels that simultaneously process the CCD signals. Distinctive capability of analog-to-digital conversion enables us to construct a CCD camera body that outputs only digital signals. As the result of the front-end electronics test, it works properly with low input noise of ≤ 30 μ V at the pixel rate below 100 kHz. The power consumption is sufficiently low of ∼ 150 mW / chip . The input signal range of ±20 mV covers the effective energy range of the typical X-ray photon counting CCD (up to 20 keV). The integrated non-linearity is 0.2% that is similar as those of the conventional CCDs in orbit. We also performed a radiation tolerance test against the total ionizing dose (TID) effect and the single event effect. The irradiation test using 60 Co and proton beam showed that the ASIC has the sufficient tolerance against TID up to 200 krad, which absolutely exceeds the expected amount of dose during the period of operating in a low-inclination low-earth orbit. The irradiation of Fe ions with the fluence of 5.2×10 8 Ion/cm 2 resulted in no single event latchup (SEL), although there were some possible single event upsets. The threshold against SEL is higher than 1.68 MeV cm 2 /mg, which is sufficiently high enough that the SEL event should not be one of major causes of instrument downtime in orbit.
BackgroundTime series gene expression data analysis is used widely to study the dynamics of various cell processes. Most of the time series data available today consist of few time points only, thus making the application of standard clustering techniques difficult.ResultsWe developed two new algorithms that are capable of extracting biological patterns from short time point series gene expression data. The two algorithms, ASTRO and MiMeSR, are inspired by the rank order preserving framework and the minimum mean squared residue approach, respectively. However, ASTRO and MiMeSR differ from previous approaches in that they take advantage of the relatively few number of time points in order to reduce the problem from NP-hard to linear. Tested on well-defined short time expression data, we found that our approaches are robust to noise, as well as to random patterns, and that they can correctly detect the temporal expression profile of relevant functional categories. Evaluation of our methods was performed using Gene Ontology (GO) annotations and chromatin immunoprecipitation (ChIP-chip) data.ConclusionOur approaches generally outperform both standard clustering algorithms and algorithms designed specifically for clustering of short time series gene expression data. Both algorithms are available at http://www.benoslab.pitt.edu/astro/.
We discuss far-UV (FUV) (1500 Å) surface photometry and FUV-B color profiles for eight E/S0 galaxies from images taken with the Ultraviolet Imaging Telescope, primarily during the Astro-2 mission. In three cases, the FUV radial profiles are more consistent with an exponential than a de Vaucouleurs function, but there is no other evidence for the presence of a disk or of young, massive stars. In all cases except M32, the FUV-B color becomes redder at larger radii. There is a wide range of internal radial FUV-B color gradients. However, we find no correlation between the FUV-B color gradients and internal metallicity gradients based on Mg absorption features. We conclude that metallicity is not the sole parameter controlling the "UV upturn component" in old populations.