298 research outputs found
MITO measurements of the Sunyaev-Zeldovich Effect in the Coma cluster of galaxies
We have measured the Sunyaev-Zeldovich effect towards the Coma cluster
(A1656) with the MITO experiment, a 2.6-m telescope equipped with a 4-channel
17 arcminute (FWHM) photometer. Measurements at frequency bands 143+/-15,
214+/-15, 272+/-16 and 353+/-13 GHz, were made during 120 drift scans of Coma.
We describe the observations and data analysis that involved extraction of the
S-Z signal by employing a spatial and spectral de-correlation scheme to remove
a dominant atmospheric component. The deduced values of the thermal S-Z effect
in the first three bands are DT_{0} = -179+/-38,-33+/-81,170+/-35 microKelvin
in the cluster center. The corresponding optical depth, tau=(4.1+/-0.9)
10^{-3}, is consistent (within errors) with both the value from a previous low
frequency S-Z measurement, and the value predicted from the X-ray deduced gas
parameters.Comment: Ap.J.Letters accepted, 4 pages, 2 figure
Geographical interdependence, international trade and economic dynamics: the Chinese and German solar energy industries
The trajectories of the German and Chinese photovoltaic industries differ significantly yet are strongly interdependent. Germany has seen a rapid growth in market demand and a strong increase in production, especially in the less developed eastern half of the country. Chinese growth has been export driven. These contrasting trajectories reflect the roles of market creation, investment and credit and the drivers of innovation and competitiveness. Consequent differences in competiveness have generated major trade disputes
Hydrogen-like nitrogen radio line from hot interstellar and warm-hot intergalactic gas
Hyperfine structure lines of highly-charged ions may open a new window in
observations of hot rarefied astrophysical plasmas. In this paper we discuss
spectral lines of isotopes and ions abundant at temperatures 10^5-10^7 K,
characteristic for warm-hot intergalactic medium, hot interstellar medium,
starburst galaxies, their superwinds and young supernova remnants. Observations
of these lines will allow to study bulk and turbulent motions of the observed
target and will broaden the information about the gas ionization state,
chemical and isotopic composition.
The most prospective is the line of the major nitrogen isotope having
wavelength 5.65 mm (Sunyaev and Churazov 1084). Wavelength of this line is
well-suited for observation of objects at z=0.15-0.6 when it is redshifted to
6.5-9 mm spectral band widely-used in ground-based radio observations, and, for
example, for z>=1.3, when the line can be observed in 1.3 cm band and at lower
frequencies. Modern and future radio telescopes and interferometers are able to
observe the absorption by 14-N VII in the warm-hot intergalactic medium at
redshifts above z=0.15 in spectra of brightest mm-band sources. Sub-millimeter
emission lines of several most abundant isotopes having hyperfine splitting
might also be detected in spectra of young supernova remnants.Comment: 12 pages, 5 figures, accepted by Astronomy Letters; v3: details
added; error fixe
An Instrument For Investigation of the Cosmic Microwave Background Radiation at Intermediate Angular Scales
We describe an off-axis microwave telescope for observations of the
anisotropy in the cosmic microwave background (CMB) radiation on angular scales
between 0.5 deg and 3 deg. The receiver utilizes cryogenic
high-electron-mobility transistor (HEMT) amplifiers and detects the total power
in multiple 3 GHz wide channels. Both frequency and polarization information
are recorded allowing discrimination between CMB radiation and potential
foreground sources and allowing checks for systematic effects. The instrumental
radiometric offset is small (~1 mK). Data are taken by rapidly sampling while
sweeping the beam many beamwidths across the sky. After detection, a
spatio-temporal filter is formed in software which optimizes the sensitivity in
a multipole band in the presence of atmospheric fluctuations. Observations were
made from Saskatoon, Saskatchewan (SK), Canada during the winter of 1993 with
six channels between 27.6 and 34.0 GHz, in 1994 with twelve channels between
27.6 and 44.1 GHz, and in 1995 with six channels between 38.2 and 44.1 GHz. The
performance of the instrument and assessment of the atmospheric noise at this
site are discussed.Comment: latex file is called inst.tex. 30 pages with 14 Postscript figures.
Uses aas2pp4.sty (included). Submitted to Ap
The UV-SCOPE mission: ultraviolet spectroscopic characterization of planets and their environments
UV-SCOPE is a mission concept to determine the causes of atmospheric mass loss in exoplanets, investigate the mechanisms driving aerosol formation in hot Jupiters, and study the influence of the stellar environment on atmospheric evolution and habitability. As part of these investigations, the mission will generate a broad-purpose legacy database of time-domain ultraviolet (UV) spectra for nearly 200 stars and planets. The observatory consists of a 60 cm, f/10 telescope paired to a long-slit spectrograph, yielding simultaneous, almost continuous coverage between 1203 Å and 4000 Å, with resolutions ranging from 6000 to 240. The efficient instrument provides throughputs < 4% (far-UV; FUV) and < 15% (near-UV; NUV), comparable to HST/COS and much better than HST/STIS, over the same spectral range. A key design feature is the LiF prism, which serves as a dispersive element and provides high throughput even after accounting for radiation degradation. The use of two delta-doped Electron-Multiplying CCD detectors with UV-optimized, single-layer anti-reflection coatings provides high quantum efficiency and low detector noise. From the Earth-Sun second Lagrangian point, UV-SCOPE will continuously observe planetary transits and stellar variability in the full FUV-to-NUV range, with negligible astrophysical background. All these features make UV-SCOPE the ideal instrument to study exoplanetary atmospheres and the impact of host stars on their planets. UV-SCOPE was proposed to NASA as a Medium Explorer (MidEx) mission for the 2021 Announcement of Opportunity. If approved, the observatory will be developed over a 5-year period. Its primary science mission takes 34 months to complete. The spacecraft carries enough fuel for 6 years of operations
Experimental evidence of the ferroelectric phase transition near the point in liquid water
We studied dielectric properties of nano-sized liquid water samples confined
in polymerized silicates MCM-41 characterized by the porous sizes \sim 3-10nm.
We report the direct measurements of the dielectric constant by the dielectric
spectroscopy method at frequencies 25Hz-1MHz and demonstrate clear signatures
of the second-order phase transition of ferroelectric nature at temperatures
next to the \lambda- point in the bulk supercooled water. The presented results
support the previously developed polar liquid phenomenology and hence establish
its applicability to model actual phenomena in liquid water.Comment: 4 pages, single figur
Are the affluent prepared to pay for the planet? Explaining willingness to pay for public and quasi-private environmental goods in Switzerland
A large number of ‘environmental justice’ studies show that wealthier people are less affected by environmental burdens and also consume more resources than poorer people. Given this double inequity, we ask, to what extent are affluent people prepared to pay to protect the environment? The analyses are couched within the compensation/affluence hypothesis, which states that wealthier persons are able to spend more for environmental protection than their poorer counterparts. Further, we take into account various competing economic, psychological and sociological determinants of individuals’ willingness to pay (WTP) for both public environmental goods (e.g., general environmental protection) and quasi-private environmental goods (e.g., CO2-neutral cars). Such a comprehensive approach contrasts with most other studies in this field that focus on a limited number of determinants and goods. Multivariate analyses are based on a general population survey in Switzerland (N = 3,369). Although income has a positive and significant effect on WTP supporting the compensation hypothesis, determinants such as generalized interpersonal trust that is assumed to be positively associated with civic engagement and environmental concern prove to be equally important. Moreover, we demonstrate for the first time that time preferences can considerably influence survey-based WTP for environmental goods; since investments in the environment typically pay off in the distant future, persons with a high subjective discount rate are less likely to commit
Individual Behavior as a Pathway between Early-Life Shocks and Adult Health: Evidence from Hunger Episodes in Post-War Germany
Phosphorylation of Chromosome Core Components May Serve as Axis Marks for the Status of Chromosomal Events during Mammalian Meiosis
Meiotic recombination and chromosome synapsis between homologous chromosomes are essential for proper chromosome segregation at the first meiotic division. While recombination and synapsis, as well as checkpoints that monitor these two events, take place in the context of a prophase I-specific axial chromosome structure, it remains unclear how chromosome axis components contribute to these processes. We show here that many protein components of the meiotic chromosome axis, including SYCP2, SYCP3, HORMAD1, HORMAD2, SMC3, STAG3, and REC8, become post-translationally modified by phosphorylation during the prophase I stage. We found that HORMAD1 and SMC3 are phosphorylated at a consensus site for the ATM/ATR checkpoint kinase and that the phosphorylated forms of HORMAD1 and SMC3 localize preferentially to unsynapsed chromosomal regions where synapsis has not yet occurred, but not to synapsed or desynapsed regions. We investigated the genetic requirements for the phosphorylation events and revealed that the phosphorylation levels of HORMAD1, HORMAD2, and SMC3 are dramatically reduced in the absence of initiation of meiotic recombination, whereas BRCA1 and SYCP3 are required for normal levels of phosphorylation of HORMAD1 and HORMAD2, but not of SMC3. Interestingly, reduced HORMAD1 and HORMAD2 phosphorylation is associated with impaired targeting of the MSUC (meiotic silencing of unsynapsed chromatin) machinery to unsynapsed chromosomes, suggesting that these post-translational events contribute to the regulation of the synapsis surveillance system. We propose that modifications of chromosome axis components serve as signals that facilitate chromosomal events including recombination, checkpoint control, transcription, and synapsis regulation
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