Laser development for LISA

The two most promising configurations for the LISA laser are a stand-alone diode-pumped nonplanar ring oscillator (NPRO) or a fibre amplifier seeded by a low-power NPRO. The stand-alone laser was stabilized in frequency to a ULE cavity and in power to an electronic reference. For the first time the LISA requirement of relative power noise below 2 × 10-4/Hz1/2 was fulfilled in the whole frequency range from 0.1 mHz to 1 Hz. The LISA goal of frequency noise below 30 Hz/Hz1/2 was achieved for frequencies above 3 mHz. As a first step in the characterization of an oscillator-amplifier system, the excess frequency noise of an ytterbium-doped fibre amplifier was measured. For frequencies between 0.1 mHz and 1 Hz the excess noise was measured to be below 0.1 Hz/Hz1/2, which is significantly below the free-running frequency noise of NPROs

Exploration of the TRIM fold of MuRF1 using EPR reveals a canonical antiparallel structure and extended COS-box

MuRF1 (TRIM63) is a RING-type E3 ubiquitin ligase with a predicted tripartite TRIM fold. TRIM proteins rely upon the correct placement of an N-terminal RING domain, with respect to C-terminal, specific substrate-binding domains. The TRIM domain organization is orchestrated by a central helical domain that forms an antiparallel coiled-coil motif and mediates the dimerization of the fold. MuRF1 has a reduced TRIM composition characterized by a lack of specific substrate binding domains, but contains in its helical domain a conserved sequence motif termed COS-box that has been speculated to fold independently into an α-hairpin. These characteristics had led to question whether MuRF1 adopts a canonical TRIM fold. Using a combination of electron paramagnetic resonance, on spin-labeled protein, and disulfide crosslinking, we show that TRIM63 follows the structural conservation of the TRIM dimerization domain, observed in other proteins. We also show that the COS-box motif folds back onto the dimerization coiled-coil motif, predictably forming a four-helical bundle at the center of the protein and emulating the architecture of canonical TRIMs.publishe

Interferometric characterization of the optical window for LISA Pathfinder and LISA

In LISA Pathfinder and LISA the position fluctuations of drag free test masses will be determined interferometrically to picometer precision. To this end, laser light is brought to interference on an ultra stable optical bench after being reflected on the test mass, which needs to be in an ultra-high vacuum. The present baseline for both missions includes a separate vacuum enclosure for each test mass, so that the sensing laser beam has to pass through an optical window. This window is therefore a transmissive element in the interferometer and its associated pathlength fluctuations are potentially significant. We have selected an athermal glass that should minimize the thermally induced pathlength changes.Several prototype windows, both mounted and unmounted, have been produced and characterized. The pathlength sensitivity to both temperature fluctuations and temperature gradients has been measured with a dedicated interferometer prototype. We have also compared the long-term stability of the LISA Technology Package interferometer when an optical window is present in the optical path to the situation without window. Finally, glass samples have been radiated and the absorption in the glass after the radiation tests has been measured to be negligible at the wavelength of interest (1064 nm). We present here the results of our measurements, which indicate that using a window does not influence the interferometer performance

Nonlinear acousto-electric transport in a two-dimensional electron system

We study both theoretically and experimentally the nonlinear interaction between an intense surface acoustic wave and a two-dimensional electron plasma in semiconductor-piezocrystal hybrid structures. The experiments on hybrid systems exhibit strongly nonlinear acousto-electric effects. The plasma turns into moving electron stripes, the acousto-electric current reaches its maximum, and the sound absorption strongly decreases. To describe the nonlinear phenomena, we develop a coupled-amplitude method for a two-dimensional system in the strongly nonlinear regime of interaction. At low electron densities the absorption coefficient decreases with increasing sound intensity, whereas at high electron density the absorption coefficient is not a monotonous function of the sound intensity. High-harmonic generation coefficients as a function of the sound intensity have a nontrivial behavior. Theory and experiment are found to be in a good agreement.Comment: 27 pages, 6 figure

Obserwacje nad jęykiem dziecka [Observation of child language]

Abstracted in Psychological Abstracts (1934) 8, 153, 1

Investment in Gdańsk

Polskę na przestrzeni kilku ostatnich lat charakteryzuje wyjątkowo duża dynamika w zakresie realizacji inwestycji infrastrukturalnych. Stało się to możliwe dzięki przystąpieniu Polski do Unii Europejskiej i możliwości pozyskania środków finansowych z funduszy strukturalnych UE na realizację inwestycji. Tym samym stworzyliśmy sobie szansę na zmniejszenie dystansu cywilizacyjnego, który pod względem jakości życia i poziomu infrastruktury dzielił Polskę od standardów w miastach unijnych.Over recent times Poland has experienced extremely dynamic growth in infrastructure investment. This has become possible due to the country’s membership of the European Union and the possibility of obtaining support for investment projects from the EU’s structural funds. An opportunity has thus been created to reduce the differences, in terms of quality of life and standard of infrastructure, that has existed between Poland and towns in other EU countries

Effect of 15N fertilisation on the yielding and phosphorus and sulphur contents in eastern galega (Galega orientalis Lam.) and soil

Trzyletnie doświadczenie polowe przeprowadzono na polu doświadczalnym należącym do Uniwersytetu Przyrodniczo-Humanistycznego w Siedlcach. Azot 15N o wzbogaceniu 10,3 at % stosowano w formie 15(NH4)2SO4 w ilości 1,66g na 1 m2 wczesną wiosną. W każdym roku badań zbierano trzy pokosy rośliny testowej w fazie pąkowania. Zawartość fosforu i siarki w roślinie testowej i w glebie oznaczono metodą ICP-AES na spektrofotometrze emisyjnym z plazmą wzbudzaną indukcyjnie. Następnie obliczono pobranie fosforu i siarki z plonem rośliny testowej. W warunkach stosowania 15N wystąpiło zmniejszenie plonu, zawartości fosforu w biomasie kolejnych pokosów rutwicy wschodniej i w kolejnych latach badań oraz zmniejszenie pobrania fosforu i siarki z plonem. Zawartość siarki zwiększała w pierwszego kolejnych pokosach rutwicy. W kolejnych latach badań oznaczano w glebie mniejszą zawartość fosforu i siarki.A three-year field experiment was conducted in the experimental site belonging to the Siedlce University of Natural Sciences and Humanities. Nitrogen 15N at 10.3% enrichment was applied in the form of 15(NH4)2SO4 at the amount of 1.66 g per 1 m2 in early spring. In each year of the study three cuts of the test plant were harvested at the stage of budding. The total content of P and S in the plant and soil was determined by emission spectrophotometr with inductively coupled plasma (ICP – AES). The uptake of phosphorus and sulphur with the yield of the test plant was then calculated. Under the conditions of 15N application there was a reduction in the yield and in phosphorus content in the biomass of successive cuts of eastern galega and in the subsequent years of the study, and a reduction of phosphorus and sulphur uptake with the yield. The sulphur content increased in the consecutive cuts with respect to the first cut. In the subsequent years of the study decreased levels of phosphorus and sulphur were assayed in the soil

Protein design by fusion: implications for protein structure prediction and evolution

Domain fusion is a useful tool in protein design. Here, the structure of a fusion of the heterodimeric flagella-assembly proteins FliS and FliC is reported. Although the ability of the fusion protein to maintain the structure of the heterodimer may be apparent, threading-based structural predictions do not properly fuse the heterodimer. Additional examples of naturally occurring heterodimers that are homologous to full-length proteins were identified. These examples highlight that the designed protein was engineered by the same tools as used in the natural evolution of proteins and that heterodimeric structures contain a wealth of information, currently unused, that can improve structural predictions.open1121sciescopu