Maturation of nuclear lamin A involves a specific carboxy-terminal trimming, which removes the polyisoprenylation site from the precursor; implications for the structure of the nuclear lamina.

Lamin A, a nuclear lamina protein of differentiated cells, is synthesized as a precursor of the mature molecule. Protein sequencing of the carboxyterminal 14 kDa fragment shows a lack of the last 18 residues predicted by cDNA sequencing. The carboxy-terminal proteolytic maturation explains previous biochemical results including the loss of the polyisoprenylation site now located to the CXXM motif at the end of the chain. This view and earlier results on lamin B predict multiple post-translational modifications shared by lamins A and B. While retained by lamin B, which is present in all cells, they are lost by maturation from lamin

A Possible Aeronomy of Extrasolar Terrestrial Planets

Terrestrial planetary systems may exist around nearby stars as the Earth-sized counterparts to the many giant planets already discovered within the solar neighborhood. In this chapter we first discuss the numerous techniques which have been suggested to search for extrasolar terrestrial planets. We then focus on the expected results from that technique in which an orbiting telescope or interferometer is used to obtain a visible or infrared spectrum of a planet, without contamination from the parent star. We show examples of such spectra for selected cases: the present Earth, the Neoproterozoic (snowball) Earth, a methane-rich Earth, and the present Mars and Venus. We conclude by discussing the implications of such spectra for the detection of life on an extrasolar terrestrial planet.Comment: This will appear in the upcoming AGU Monograph 130 "Atmospheres in the Solar System: Comparative Aeronomy". It will be on page 36

Measurement of H2O and other trace gases in the stratosphere using a high resolution far-infrared spectrometer at 28 km

Data analysis results from the 1983 BIC 1 and 2 balloon flights are presented, with emphasis on H2O2, OH, HCL, O3, O2, and H2O. A 2 sigma limit on H2O2 abundance was set, as a function of altitude. This is comparable to or less than the theoretically predicted winter abundances from the 2-D models of Dupont, with a large enough summer maximum to facilitate concentration profile measurements. There is a definite drop in OH concentration from day to night following two model profiles. There was general agreement between HF measurements. The dominant role of the far wings of H2O lines in low altitude spectra was recognized. The strength of these wings exceeds that of many molecular line cores, including O3 and O2, especially near the long wavelength end of the spectra (100 cm (-1)). Newly measured positions for O3 and H2O were obtained

Measurement of H2O and other trace gases in the stratosphere using a high resolution far-infrared spectrometer at 28 KM

The highlights of the stratospheric program were reviewed for the past 2.5 years. The major efforts were analysis of the data from the BIC-2 campaign, and the building or new instrumentation to replace that lost at the end of BIC-2. For clarity, the review will be done by topic, rather than chronologically: construction of the initial far-infrared spectrometer, balloon slight program, laboratory measurement, data analysis, and duplicate stabilized platform

Atmospheric Biomarkers and their Evolution over Geological Timescales

The search for life on extrasolar planets is based on the assumption that one can screen extrasolar planets for habitability spectroscopically. The first space born instruments able to detect as well as characterize extrasolar planets, Darwin and terrestrial planet finder (TPF-I and TPF-C) are scheduled to launch before the end of the next decade. The composition of the planetary surface, atmosphere, and its temperature-pressure profile influence a detectable spectroscopic signal considerably. For future space-based missions it will be crucial to know this influence to interpret the observed signals and detect signatures of life in remotely observed atmospheres. We give an overview of biomarkers in the visible and IR range, corresponding to the TPF-C and TPF-I/DARWIN concepts, respectively. We also give an overview of the evolution of biomarkers over time and its implication for the search for life on extrasolar Earth-like planets. We show that atmospheric features on Earth can provide clues of biological activities for at least 2 billion years.Comment: for high resolution images see http://cfa-www.harvard.edu/~lkaltenegge

Protein chemical analysis of purified murine lamin B identifies two distinct polypeptides B1 and B2.

Lamin B purified from murine EAT cells was characterized by partial protein sequences. Contrary to the current view that mammals express only a single lamin B polypeptide corresponding to a characterized murine cDNA clone, our analysis documents two distinct B lamins. One protein follows the estabished cDNA sequence while the other identifies a novel murine lamin B. Comparison with the two chicken lamin B sequences established by cDNA cloning identifies the first murine lamin B sequence as a B1 type and the second as a B2 type. We conclude that mammals express two distinct lamin B forms as established by others for chicken

Astrometric jitter of the sun as a star

The daily variation of the solar photocenter over some 11 years is derived from the Mount Wilson data reprocessed by Ulrich et al. 2010 to closely match the surface distribution of solar irradiance. The standard deviations of astrometric jitter are 0.52 $\mu$AU and 0.39 $\mu$AU in the equatorial and the axial dimensions, respectively. The overall dispersion is strongly correlated with the solar cycle, reaching $0.91 \mu$AU at the maximum activity in 2000. The largest short-term deviations from the running average (up to 2.6 $\mu$AU) occur when a group of large spots happen to lie on one side with respect to the center of the disk. The amplitude spectrum of the photocenter variations never exceeds 0.033 $\mu$AU for the range of periods 0.6--1.4 yr, corresponding to the orbital periods of planets in the habitable zone. Astrometric detection of Earth-like planets around stars as quiet as the Sun is not affected by star spot noise, but the prospects for more active stars may be limited to giant planets.Comment: Accepted in Ap

Роль дизъюнктивных нарушений в распределении, формировании и разрушении залежей газа на Малохетском валу (северо-восток Западно-Сибирской низменности)

High reliable diode laser pump modules are essential for free-space optical telecommunications. Besides the reliability, low mass and small dimensions, radiation-hardness and low power-consumption are requirements to be met for space applications. A diode laser module suited for pumping Nd:YAG lasers for optical intersatellite links has been developed. The module consists of two diode laser bars overlaid by a polarization beam splitter to increase the system's reliability. Each diode laser bar consists of six emitters. If the integrated photodiode detects the failure of one bar, the second, substitute bar is switched on and can fully sustain all module functions. To equalize the beam quality of the diode laser bar, a pair of micro step mirrors is used for each bar. The laser beam is focussed on the entrance of a d=200 µm, NA=0.22 fiber. Both the coupling efficiency and the accuracy of the mounting of the diode laser components have been analyzed by raytracing. Passive cooling has been chosen because liquid chilling systems are unsuitable for space applications. To evaluate the effects of different heat sink materials and to predict the temperature drop over the module, a 3D finite element analysis for the steady-state temperature distribution of the module has been performed. The optical output power of the module described above amounts to 2,8 W with one bar operating derated to 0.5x maximum current, and the whole unit fits in a housing of 78 x 50 x 24 mm. Further developments will lead to a more compact design and a smaller fiber diameter