2,339 research outputs found
Isoenzymatic Characterization of Native and Cultivated Forage Legume Species of Rio Grande Do Sul (Southern Brazil)
Esterase (EST), malic enzyme (ME) and superoxidodismutase (SOD) patterns were studied in 26 accessions of the Vicia sativa aggregate, including V.sativa, V.angustifolia and V.cordata. ME was monomorphic but for EST and SOD intra and interspecific and also intrapopulation polymorphism was detected. An EST marker band was detected for V.cordata. EST patterns did not allow a clear separation between V.sativa and V.angustifolia but SOD patterns grouped the taxa in general accordance with taxonomic classification. The results agree with previous reports on polymorphism in European populations of the aggregate and show that isozymes can be useful genetic markers for the study of the Vicia sativa-V.angustifolia complex
Back-Surface Passivation for High-Efficiency Crystalline Silicon Solar Cells: Final Technical Progress Report, September 2010 -- May 2012
Final technical progress report for TetraSun, a Photovoltaic Technology Incubator awardee within the U.S. Department of Energy's (DOE) SunShot Program
OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis
Background: The quantitative analysis of metabolic fluxes, i. e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i) tracer cultivation on C-13 substrates, (ii) C-13 labelling analysis by mass spectrometry and (iii) mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis
Northwest Africa 10658, a Uniquely Shocked Eucrite with a Range of Deformation, Transformation and Recrystallization Effects
Impacts are a fundamental geologic process that has influenced the formation and modification of asteroids and planets throughout time. An important part of the impact history of the solar system is recorded in shocked meteorites. The asteroid Vesta has experienced large impacts, evidenced by two ~400-500 km impact structures that overprint the south pole region. While a range of shock-induced effects such as brecciation, melting and
the formation of maskelynite has been reported in howardite-eucrite-diogenite (HED) meteorites originating from
Vesta, high-pressure minerals have previously only been described in two eucrites [1-2]. Here, we present results on
an inventory of shock effects and high-pressure minerals preserved in the polymict eucrite NWA 10658
GREGOR, a 1.5 m Gregory-type telescope for solar observation
GREGOR is a high-resolution solar telescope with an aperture of 1.5 m. It will be equipped with an adaptive optics system and is designed for high-precision measurements of magnetic fields and plasma motions in the solar atmosphere and chromosphere with a resolution of 70 km on the Sun. GREGOR will replace the 30 years old Gregory Coude Telescope at the Observatorio del Teide on Tenerife. We describe the optical design and the focal plane instrumentation. In concert with the other solar telescopes at Teide Observatory it will be useful for studying the dynamics of the solar atmosphere and of the underlying processes. GREGOR will also serve as a test bed for
next-generation solar telescopes
Active sites in Escherichia coli ribosomes
AbstractIn the figure, 30 S ribosomal proteins have been arranged according to their functional role: Protein S1 is required for mRNA binding. Proteins S3, S4, S5, S11 and S12 are involved in cistron and/or codon—anticodon recognition. They must be close to the decoding sites on the 30 S subunit. Furthermore proteins S2, S3, S10, S14, S19 and S21 function in f-Met-tRNA binding. Proteins S1, S2, S3, S10, S14, S19, S20 and S21 are important for the function of both decoding sites, whereas proteins S9, S11 and S18 are only needed for EF—Tu-dependent aminoacyl-tRNA binding. Proteins S2, S5, S9 and S11 would be close to the GTPase center of the 50 S subunit, since they are important for this activity.The present available data concerning the 50 S subunit allow the following picture to be drawn: Protein L16 is involved in binding the 3′-terminus of aminoacyl-tRNA in the A-site. Next to it in the A-site, there is protein L6. The P-site is located adjacent to the A-site of the peptidyltransferase center. Accordingly, protein L2 is near protein L6 and is located in the P-site as well as proteins L27 and L4. Protein L11, which is intimately involved in peptide bond formation, would have to border parts of both A- and P-sites. Proteins L6 and L2 stimulate binding of 5 S RNA—protein complexes to 23 S RNA. The 5 S RNA—protein complex has GTPase and ATPase activities. The proteins in this complex (L5, L18, L20, L25 and L30) seem to be located close to the A-site of the peptidyltransferase center. These proteins together with protein L11 are involved in GDP binding. Proteins L10 and L6 are implicated in reconstitution of protein L7 and L12 mediated EF—G-dependent ribosomal GTP hydrolysis. This observation is supported by the fact that the aminoacyl-tRNA binding site, e.g. proteins L16 and L6, is connected with EF—G and EF—Tu binding site, e.g. proteins L7 and L12, as well as the GTPase center. Furthermore, if one of the functional roles of 5 S RNA is to bind aminoacyl-tRNA via T—Ψ—C, then those ribosomal proteins which bind to 5 S RNA (or are close to it) would be located near or at the A-site.The model of active sites in E. coli ribosome illustrated in the figure is based on the presently available experimental results. It is far from being complete and should not be overinterpreted as an accurate topographical model. More data on the functional role of ribosomal components and on the topography of the subunits can be expected in the near future and will add to the knowledge on the active sites in ribosomes
River damming affects seedling communities of a floodplain forest in the Central Amazon
The flood pulse of black water rivers in the Amazon basin determines the composition of species along the flood gradient in igapĂł forests. The Balbina dam, built on the UatumĂŁ River, has altered the flood pulse and caused changes in the floristic composition of adult trees throughout the downstream area. There is a lack of studies on how communities of seedlings in igapĂł forests respond to changes in the flood pulse. This study investigates the response of seedling communities in the igapĂł forest downstream the Balbina dam and compares it with two pristine areas. The areas were sampled with transects of 1x25 m within 36 plots (25x25 m) along the flood gradient. Richness and dominance were calculated by simple regression and ordination analyses. The pristine areas had the same pattern of richness, dominance and genera distribution along the flood gradient. However, the affected UatumĂŁ area formed different groups of genera by NMDS analysis, which divided them along the flood gradient with significantly increased dominance of three genera. The insertion of the Balbina dam resulted a loss of lateral and longitudinal connectivity for the UatumĂŁ River, and the alteration to seedling communities may alter the future landscape of downstream igapĂł forests
The GREGOR Fabry-P\'erot Interferometer
The GREGOR Fabry-P\'erot Interferometer (GFPI) is one of three first-light
instruments of the German 1.5-meter GREGOR solar telescope at the Observatorio
del Teide, Tenerife, Spain. The GFPI uses two tunable etalons in collimated
mounting. Thanks to its large-format, high-cadence CCD detectors with
sophisticated computer hard- and software it is capable of scanning spectral
lines with a cadence that is sufficient to capture the dynamic evolution of the
solar atmosphere. The field-of-view (FOV) of 50" x 38" is well suited for quiet
Sun and sunspot observations. However, in the vector spectropolarimetric mode
the FOV reduces to 25" x 38". The spectral coverage in the spectroscopic mode
extends from 530-860 nm with a theoretical spectral resolution R of about
250,000, whereas in the vector spectropolarimetric mode the wavelength range is
at present limited to 580-660 nm. The combination of fast narrow-band imaging
and post-factum image restoration has the potential for discovery science
concerning the dynamic Sun and its magnetic field at spatial scales down to
about 50 km on the solar surface.Comment: 14 pages, 17 figures, 4 tables; pre-print of AN 333, p.880-893, 2012
(AN special issue to GREGOR
Reward During Arm Training Improves Impairment and Activity After Stroke: A Randomized Controlled Trial
Background Learning and learning-related neuroplasticity in motor cortex are potential mechanisms mediating recovery of movement abilities after stroke. These mechanisms depend on dopaminergic projections from midbrain that may encode reward information. Likewise, therapist experience confirms the role of feedback/reward for training efficacy after stroke. Objective To test the hypothesis that rehabilitative training can be enhanced by adding performance feedback and monetary rewards. Methods This multicentric, assessor-blinded, randomized controlled trial used the ArmeoSenso virtual reality rehabilitation system to train 37 first-ever subacute stroke patients in arm-reaching to moving targets. The rewarded group (n = 19) trained with performance feedback (gameplay) and contingent monetary reward. The control group (n = 18) used the same system without monetary reward and with graphically minimized performance feedback. Primary outcome was the change in the two-dimensional reaching space until the end of the intervention period. Secondary clinical assessments were performed at baseline, after 3 weeks of training (15 1-hour sessions), and at 3 month follow-up. Duration and intensity of the interventions as well as concomitant therapy were comparable between groups. Results The two-dimensional reaching space showed an overall improvement but no difference between groups. The rewarded group, however, showed significantly greater improvements from baseline in secondary outcomes assessing arm activity (Box and Block Test at post-training: 6.03±2.95, P = .046 and 3 months: 9.66±3.11, P = .003; Wolf Motor Function Test [Score] at 3 months: .63±.22, P = .007) and arm impairment (Fugl-Meyer Upper Extremity at 3 months: 8.22±3.11, P = .011). Conclusions Although neutral in its primary outcome, the trial signals a potential facilitating effect of reward on training-mediated improvement of arm paresis. Trial registration ClinicalTrials.gov (ID: NCT02257125)
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