1,561 research outputs found
Pscroph, a parasitic plant EST database enriched for parasite associated transcripts
BACKGROUND: Parasitic plants in the Orobanchaceae develop invasive root haustoria upon contact with host roots or root factors. The development of haustoria can be visually monitored and is rapid, highly synchronous, and strongly dependent on host factor exposure; therefore it provides a tractable system for studying chemical communications between roots of different plants. DESCRIPTION: Triphysaria is a facultative parasitic plant that initiates haustorium development within minutes after contact with host plant roots, root exudates, or purified haustorium-inducing phenolics. In order to identify genes associated with host root identification and early haustorium development, we sequenced suppression subtractive libraries (SSH) enriched for transcripts regulated in Triphysaria roots within five hours of exposure to Arabidopsis roots or the purified haustorium-inducing factor 2,6 dimethoxybenzoquinone. The sequences of over nine thousand ESTs from three SSH libraries and their subsequent assemblies are available at the Pscroph database . The web site also provides BLAST functions and allows keyword searches of functional annotations. CONCLUSION: Libraries prepared from Triphysaria roots treated with host roots or haustorium inducing factors were enriched for transcripts predicted to function in stress responses, electron transport or protein metabolism. In addition to parasitic plant investigations, the Pscroph database provides a useful resource for investigations in rhizosphere interactions, chemical signaling between organisms, and plant development and evolution
Complementation of the Tomato anthocyanin without (aw) Mutant Using the Dihydroflavonol 4-Reductase Gene
Program for the evaluation of structural reinforced plastic materials at cryogenic temperatures, phase ii annual and fourth quarterly report, 29 jun. 1964 - 30 jun. 1965
Evaluation of procedures, test specimens, and test techniques for application to structural reinforced plastic materials at cryogenic temperature
Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited
This report is a review of Darwin's classical theory of bodily tides in which
we present the analytical expressions for the orbital and rotational evolution
of the bodies and for the energy dissipation rates due to their tidal
interaction. General formulas are given which do not depend on any assumption
linking the tidal lags to the frequencies of the corresponding tidal waves
(except that equal frequency harmonics are assumed to span equal lags).
Emphasis is given to the cases of companions having reached one of the two
possible final states: (1) the super-synchronous stationary rotation resulting
from the vanishing of the average tidal torque; (2) the capture into a 1:1
spin-orbit resonance (true synchronization). In these cases, the energy
dissipation is controlled by the tidal harmonic with period equal to the
orbital period (instead of the semi-diurnal tide) and the singularity due to
the vanishing of the geometric phase lag does not exist. It is also shown that
the true synchronization with non-zero eccentricity is only possible if an
extra torque exists opposite to the tidal torque. The theory is developed
assuming that this additional torque is produced by an equatorial permanent
asymmetry in the companion. The results are model-dependent and the theory is
developed only to the second degree in eccentricity and inclination
(obliquity). It can easily be extended to higher orders, but formal accuracy
will not be a real improvement as long as the physics of the processes leading
to tidal lags is not better known.Comment: 30 pages, 7 figures, corrected typo
Optimizing for periodicity: a model-independent approach to flux crosstalk calibration for superconducting circuits
Flux tunability is an important engineering resource for superconducting
circuits. Large-scale quantum computers based on flux-tunable superconducting
circuits face the problem of flux crosstalk, which needs to be accurately
calibrated to realize high-fidelity quantum operations. Typical calibration
methods either assume that circuit elements can be effectively decoupled and
simple models can be applied, or require a large amount of data. Such methods
become ineffective as the system size increases and circuit interactions become
stronger. Here we propose a new method for calibrating flux crosstalk, which is
independent of the underlying circuit model. Using the fundamental property
that superconducting circuits respond periodically to external fluxes,
crosstalk calibration of N flux channels can be treated as N independent
optimization problems, with the objective functions being the periodicity of a
measured signal depending on the compensation parameters. We demonstrate this
method on a small-scale quantum annealing circuit based on superconducting flux
qubits, achieving comparable accuracy with previous methods. We also show that
the objective function usually has a nearly convex landscape, allowing
efficient optimization
Matching arthropod anatomy ontologies to the Hymenoptera Anatomy Ontology: results from a manual alignment
Matching is an important step for increasing interoperability between heterogeneous ontologies. Here, we present alignments we produced as domain experts, using a manual mapping process, between the Hymenoptera Anatomy Ontology and other existing arthropod anatomy ontologies (representing spiders, ticks, mosquitoes and Drosophila melanogaster). The resulting alignments contain from 43 to 368 mappings (correspondences), all derived from domain-expert input. Despite the many pairwise correspondences, only 11 correspondences were found in common between all ontologies, suggesting either major intrinsic differences between each ontology or gaps in representing each group’s anatomy. Furthermore, we compare our findings with putative correspondences from Bioportal (derived from LOOM software) and summarize the results in a total evidence alignment. We briefly discuss characteristics of the ontologies and issues with the matching process.Database URL: http://purl.obolibrary.org/obo/hao/2012-07-18/arthropod-mappings.ob
On the tidal evolution of Hot Jupiters on inclined orbits
Tidal friction is thought to be important in determining the long-term
spin-orbit evolution of short-period extrasolar planetary systems. Using a
simple model of the orbit-averaged effects of tidal friction, we study the
evolution of close-in planets on inclined orbits, due to tides. We analyse the
effects of the inclusion of stellar magnetic braking by performing a
phase-plane analysis of a simplified system of equations, including the braking
torque. The inclusion of magnetic braking is found to be important, and its
neglect can result in a very different system history. We then present the
results of numerical integrations of the tidal evolution equations, where we
find that it is essential to consider coupled evolution of the orbital and
rotational elements, including dissipation in both the star and planet, to
accurately model the evolution. The main result of our integrations is that for
typical Hot Jupiters, tidal friction aligns the stellar spin with the orbit on
a similar time as it causes the orbit to decay. This means that if a planet is
observed to be aligned, then it probably formed coplanar. This reinforces the
importance of Rossiter-McLaughlin effect observations in determining the degree
of spin-orbit alignment in transiting systems. We apply these results to the
XO-3 system, and constrain the tidal quality factors Q' in both the star and
planet in this system. Using a model in which inertial waves are excited by
tidal forcing in the outer convective envelope and dissipated by turbulent
viscosity, we calculate Q' for a range of F-star models, and find it to vary
considerably within this class of stars. This means that assuming a single Q'
applies to all stars is probably incorrect. We propose an explanation for the
survival of WASP-12 b & OGLE-TR-56 b, in terms of weak dissipation in the star.Comment: 19 pages, 8 figures, accepted in MNRA
The Indiana University Neutron Polarization Facility (INPOL)
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Gender-dependent differences in plasma matrix metalloproteinase-8 elevated in pulmonary tuberculosis.
Tuberculosis (TB) remains a global health pandemic and greater understanding of underlying pathogenesis is required to develop novel therapeutic and diagnostic approaches. Matrix metalloproteinases (MMPs) are emerging as key effectors of tissue destruction in TB but have not been comprehensively studied in plasma, nor have gender differences been investigated. We measured the plasma concentrations of MMPs in a carefully characterised, prospectively recruited clinical cohort of 380 individuals. The collagenases, MMP-1 and MMP-8, were elevated in plasma of patients with pulmonary TB relative to healthy controls, and MMP-7 (matrilysin) and MMP-9 (gelatinase B) were also increased. MMP-8 was TB-specific (p<0.001), not being elevated in symptomatic controls (symptoms suspicious of TB but active disease excluded). Plasma MMP-8 concentrations inversely correlated with body mass index. Plasma MMP-8 concentration was 1.51-fold higher in males than females with TB (p<0.05) and this difference was not due to greater disease severity in men. Gender-specific analysis of MMPs demonstrated consistent increase in MMP-1 and -8 in TB, but MMP-8 was a better discriminator for TB in men. Plasma collagenases are elevated in pulmonary TB and differ between men and women. Gender must be considered in investigation of TB immunopathology and development of novel diagnostic markers
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