283 research outputs found
Estabilidad genética in vitro en cultivares de caña de azúcar
Genotypic stability and uniformity of field plants from sugarcane cultivars grown in vitro (calli and cell suspensions) were evaluated by isoenzymatic peroxidase analysis after regeneration, Phenotypes of field plants exhibited uniformity within cultivars and differences among cultivars. Distribution of PRX isoenzymes was different in the constitution of the calli phenotypes, not only among cultivars but also within the same cultivar. Genotype PR980 showed a 60% heterogeneity coefficient, whereas the call of cultivars PR62258, PR641791, PR692176, V64-10 and V71-51 showed identity coefficient of 100%. The isoenzymatic pattern of PRX for the phenotypes of cell suspensions was different among the four cuitivars used, as well as within cultivars PR980 and V64-10, all of which showed heterogeneity coefficients of 50 and 22%, respectively. Nevertheless, the identity coefficient for regenerated plants of all genotypes was 100%. In sugarcane, the isoenzyme PRX1 is related to differentiated tissue, since it is present only in phenotypes from field and regenerated plants. PRX4 is induced in vitro conditions since it was observed only in callus tissue and ceil suspensions,This study detected high uniformity and genetic stability within the regenerated plants in 100% of the sugarcane cultivars used.Se evaluó la estabilidad y uniformidad de los genotipos de plantas de campo de cultivares de caña de azúcar después de haber pasado por condiciones in vitro (callos y suspensiones celulares), a través del análisis isoenzimátíco de peroxídasa en plántulas regeneradas. Los fenotipos de tas plantas de campo exhibieron uniformidad para cada cultivar y diferencias entre los distintos cultivares. La distribución de las isoenzimas de PRX en la constitución de los fenotipos de callos mostró diferencias entre cultivares así como dentro del mismo cultivar. El genotipo PR980 alcanzó un coeficiente de heterogeneidad de 60%. Para los callos de los cultivares PR62258, PR641791, PR692176, V58-4, V64-10 y V71-51 no mostró variación, señalándose un coeficiente de identidad de 100%. El patrón isoenzfmático de PRX para la conformación de los fenotipos de las suspensiones celulares fue diferente en los cuatro cultivares usados, así como también dentro de los cultivares PR980 y V64-10, los cuales exhibieron coeficientes de heterogeneidad de 50 y 22%, respectivamente. Sin embargo, los regenerantes exhibieron un coeficiente de identidad del 100%. La isoenzima PRX1 está relacionada a tejido diferenciado en caña de azúcar ya que sólo está presente en los fenotipos de plantas de campo y regenerantes. PRX4 es inducida bajo condiciones de cultivo in vitro, visualizándose exclusivamente en tejido calloso y suspensiones celulares. Este estudio detectó, en todos los cultivares de caña de azúcar usados, una alta uniformidad y estabilidad genética entre las plántulas regeneradas
Global ocean modeling and state estimation in support of climate research
During the last decade it has become obvious that the ocean circulation shows vigorous variability on a wide range of time and space scales and that the concept of a "sluggish" and slowly varying circulation is rather elusive. Increasing emphasis has to be put, therefore, on observing the rapidly changing ocean state on time scales ranging from weeks to decades and beyond, and on understanding the ocean's response to changing atmospheric forcing conditions. As outlined in various strategy and implementation documents (e.g., the implementation plans of WOCE, AMS, CLIVAR, and GODAE) a combination of the global ocean data sets with a state-of-the-art numerical circulation model is required to interpret the various diverse data sets and to produce the best possible estimates of the time-varying ocean circulation. The mechanism of ocean state estimates is a powerful tool for such a "synthesis" of observations, obtained on very complex space-time pattern, into one dynamically consistent picture of the global time-evolving ocean circulation. This process has much in common with ongoing analysis and reanalysis activities in the atmospheric community. But because the ocean is, and will remain for the foreseeable future, substantially under-sampled, the burden put on the modeling and estimations components is substantially larger than in the atmosphere. Moreover, the smaller dynamical eddy scales which need to be properly parameterized or resolved in ocean model simulations, put stringent requirements on computational resources for ongoing and participated climate research
A five-stage treatment train for water recovery from urine and shower water for long-term human Space missions
Long-term human Space missions will rely on regenerative life support as resupply of water, oxygen and food comes with constraints. The International Space Station (ISS) relies on an evaporation/condensation system to recover 74-85% of the water in urine, yet suffers from repetitive scaling and biofouling while employing hazardous chemicals. In this study, an alternative non-sanitary five-stage treatment train for one "astronaut" was integrated through a sophisticated monitoring and control system. This so-called Water Treatment Unit Breadboard (WTUB) successfully treated urine (1.2-L-d with crystallisation, COD-removal, ammonification, nitrification and electrodialysis, before it was mixed with shower water (3.4-L-d(-1)). Subsequently, ceramic nanofiltration and single-pass flat-sheet RO were used. A four-months proof-of-concept period yielded: (i) chemical water quality meeting the hygienic standards of the European Space Agency, (ii) a 87- +/- -5% permeate recovery with an estimated theoretical primary energy requirement of 0.2-kWh p -L-1, (iii) reduced scaling potential without anti-scalant addition and (iv) and a significant biological reduction in biofouling potential resulted in stable but biofouling-limited RO permeability of 0.5 L-m(-2)-h(-1)-bar(-1). Estimated mass breakeven dates and a comparison with the ISS Water Recovery System for a hypothetical Mars transit mission show that WTUB is a promising biological membrane-based alternative to heat-based systems for manned Space missions
First Measurement of the Tensor Structure Function of the Deuteron
The \Hermes experiment has investigated the tensor spin structure of the
deuteron using the 27.6 GeV/c positron beam of \Hera. The use of a tensor
polarized deuteron gas target with only a negligible residual vector
polarization enabled the first measurement of the tensor asymmetry \At and
the tensor structure function \bd for average values of the Bj{\o}rken
variable and of the squared four-momentum transfer . The quantities \At and \bd are found to be
non-zero. The rise of \bd for decreasing values of can be interpreted to
originate from the same mechanism that leads to nuclear shadowing in
unpolarized scattering
Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target
Single-spin asymmetries for semi-inclusive electroproduction of charged pions
in deep-inelastic scattering of positrons are measured for the first time with
transverse target polarization. The asymmetry depends on the azimuthal angles
of both the pion () and the target spin axis () about the virtual
photon direction and relative to the lepton scattering plane. The extracted
Fourier component \cmpi is a signal of the previously unmeasured quark
transversity distribution, in conjunction with the so-called Collins
fragmentation function, also unknown. The Fourier component \smpi of the
asymmetry arises from a correlation between the transverse polarization of the
target nucleon and the intrinsic transverse momentum of quarks, as represented
by the previously unmeasured Sivers distribution function. Evidence for both
signals is observed, but the Sivers asymmetry may be affected by exclusive
vector meson productio
Double hadron leptoproduction in the nuclear medium
First measurement of double-hadron production in deep-inelastic scattering
has been measured with the HERMES spectrometer at HERA using a 27.6 GeV
positron beam with deuterium, nitrogen, krypton and xenon targets. The
influence of the nuclear medium on the ratio of double-hadron to single-hadron
yields has been investigated. Nuclear effects are clearly observed but with
substantially smaller magnitude and reduced -dependence compared to
previously measured single-hadron multiplicity ratios. The data are in fair
agreement with models based on partonic or pre-hadronic energy loss, while they
seem to rule out a pure absorptive treatment of the final state interactions.
Thus, the double-hadron ratio provides an additional tool for studying
modifications of hadronization in nuclear matter
Search for an exotic S=-2, Q=-2 baryon resonance at a mass near 1862 MeV in quasi-real photoproduction
A search for an exotic baryon resonance with has been performed
in quasi-real photoproduction on a deuterium target through the decay channel
. No evidence for
a previously reported resonance is found in the invariant mass spectrum. An upper limit for the photoproduction cross
section of 2.1 nb is found at the 90% confidence level. The photoproduction
cross section for the is found to be between 9 and 24 nb
Subleading-twist effects in single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized hydrogen target
Single-spin asymmetries in the semi-inclusive production of charged pions in
deep-inelastic scattering from transversely and longitudinally polarized proton
targets are combined to evaluate the subleading-twist contribution to the
longitudinal case. This contribution is significantly positive for (\pi^+)
mesons and dominates the asymmetries on a longitudinally polarized target
previously measured by \hermes. The subleading-twist contribution for (\pi^-)
mesons is found to be small
Surviving streptococcal toxic shock syndrome: a case report
Streptococcal toxic shock syndrome and associated myositis caused by group A beta-hemolytic streptococcus pyogenes generally have a poor outcome despite aggressive operative treatment. Frequently the diagnosis is missed initially as the clinical features are non-specific. The progression to a toxic state is rapid and unless definitive treatment measures are initiated early, the end result can be catastrophic. We report a previously healthy patient who had features of toxic shock syndrome due to alpha haemolytic (viridans) streptococcus mitis which was treated successfully with antibiotics, aggressive intensive care support including the use of a 'sepsis care bundle', monitoring and continuous multidisciplinary review. Life and limb threatening emergencies due to streptococcus mitis in an immune-competent person are rare and to our knowledge, have not previously been described in the English scientific literature. Successful outcome is possible provided a high degree of suspicion is maintained and the patient is intensively monitored
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