663 research outputs found
Compositional Constraints on the Best Characterized Rocky Exoplanet, Kepler-36 b
Kepler-36 is an extreme planetary system, consisting of two transiting sub-Neptune-size planets orbiting around a sub-giant star with periods of 13.84 and 16.24 days. Mutual gravitational interactions between the two planets perturb the planets' transit times, allowing the planets' masses to be measured. Despite the similarity of their masses and orbital radii, the planets show a stark contrast in their mean densities: the inner planet (Kepler-36 b) is more than eight times as dense as its outer companion planet (Kepler-36 c). We perform a photo-dynamical analysis of the Kepler-36 system based on more than three years of Kepler photometry. With N-body integrations of initial conditions sampled from the photo-dynamical fits, we further refine the properties of the system by ruling out solutions that show large scale instability within 5 billion days. Ultimately, we measure the planets' masses with 4.2% precision and the planets' radii with 1.8% precision. Kepler-36 b is the rocky exoplanet with the most precisely measured mass and radius. Kepler-36 b's mass and radius are consistent with an Earth-like composition, whereas an iron-enhanced Mercury-like composition is ruled out
Polymer Structures on Surface Acoustic Wave Biosensors
The influence of surface structuring on surface acoustic wave (SAW) biosensor signals has been investigated. Polymer structures on the sensor surfaces were applied by lithography or by self-assembling of polystyrene microparticles. In first experiments, structured and unstructured sensors led to similar results in a model affinity assay using streptavidin and biotinylated protein. On the other hand, structuring had a strong effect on SAW sensor signals obtained by protein adsorption on parylene C coated sensors. Depending on the protein, both decreased (albumin, streptavidin) and increased (fibrinogen) signals were observed with structured SAW sensors. Particularly the latter could contribute to facilitated blood analysis in the future
Comparative evaluation of [(99m)tc]tilmanocept for sentinel lymph node mapping in breast cancer patients: results of two phase 3 trials.
BackgroundSentinel lymph node (SLN) surgery is used worldwide for staging breast cancer patients and helps limit axillary lymph node dissection. [(99m)Tc]Tilmanocept is a novel receptor-targeted radiopharmaceutical evaluated in 2 open-label, nonrandomized, within-patient, phase 3 trials designed to assess the lymphatic mapping performance.MethodsA total of 13 centers contributed 148 patients with breast cancer. Each patient received [(99m)Tc]tilmanocept and vital blue dye (VBD). Lymph nodes identified intraoperatively as radioactive and/or blue stained were excised and histologically examined. The primary endpoint, concordance (lower boundary set point at 90 %), was the proportion of nodes detected by VBD and [(99m)Tc]tilmanocept.ResultsA total of 13 centers contributed 148 patients who were injected with both agents. Intraoperatively, 207 of 209 nodes detected by VBD were also detected by [(99m)Tc]tilmanocept for a concordance rate of 99.04 % (p < 0.0001). [(99m)Tc]tilmanocept detected a total of 320 nodes, of which 207 (64.7 %) were detected by VBD. [(99m)Tc]Tilmanocept detected at least 1 SLN in more patients (146) than did VBD (131, p < 0.0001). In 129 of 131 patients with ≥1 blue node, all blue nodes were radioactive. Of 33 pathology-positive nodes (18.2 % patient pathology rate), [(99m)Tc]tilmanocept detected 31 of 33, whereas VBD detected only 25 of 33 (p = 0.0312). No pathology-positive SLNs were detected exclusively by VBD. No serious adverse events were attributed to [(99m)Tc]tilmanocept.Conclusion[(99m)Tc]Tilmanocept demonstrated success in detecting a SLN while meeting the primary endpoint. Interestingly, [(99m)Tc]tilmanocept was additionally noted to identify more SLNs in more patients. This localization represented a higher number of metastatic breast cancer lymph nodes than that of VBD
Early Switch in Glial Protein and Fibronectin Markers on Cells during the Culture of Human Gliomas
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75201/1/j.1749-6632.1984.tb13851.x.pd
Properties of the a1 Meson from Lattice QCD
We determine the mass and decay constant of the meson using Monte Carlo
simulation of lattice QCD. We find MeV and , in good agreement with experiment.Comment: 9 page uu-encoded compressed postscript file. version appearing in
Phys. Rev. Lett. 74 (1995) 459
Historical Biomass Burning: Late 19th Century Pioneer Agriculture Revolution in Northern Hemisphere Ice Core Data and its Atmospheric Interpretation
Ice core data from Yukon and Greenland spanning from ∼1750 to 1950 indicate that between ∼1850 and ≤1910 a clear atmospheric signal exists of an episodic biomass burning event that is referred to as the Pioneer Agriculture Revolution. This is best seen in NH4+ ion and particulate concentrations but also in some limited black carbon concentration data, where for all three quantities maximum levels reach about 3 times the prerevolution background concentrations. Tree cellulose δ13C data and some early, controversial, French, air CO2 data, occurring within the same time interval, are interpreted as providing other independent evidence for the same, mainly North American, late 19th century biomass burning event. Some hitherto problematic northern hemisphere ice core derived CO2 concentration data may now be interpreted as containing a biomass burn signal, and these data are compared, especially as to the time of occurrence, with all the other results. A global carbon cycle model simulation of atmospheric CO2 mixing ratios using a maximum input of 3 Gt(C)/yr at northern midlatitudes produces “anomalous” CO2 levels close to some of the ice core carbon dioxide values. However, other values in this data set do not reasonably represent fully mixed atmospheric values. This suggests that these values might be transients but still “tracers” for biomass burning. Nevertheless, it appears possible that interhemispheric CO2 gradients of similar magnitude to the present one could have existed briefly late last century
Formation of Super-Earths
Super-Earths are the most abundant planets known to date and are
characterized by having sizes between that of Earth and Neptune, typical
orbital periods of less than 100 days and gaseous envelopes that are often
massive enough to significantly contribute to the planet's overall radius.
Furthermore, super-Earths regularly appear in tightly-packed multiple-planet
systems, but resonant configurations in such systems are rare. This chapters
summarizes current super-Earth formation theories. It starts from the formation
of rocky cores and subsequent accretion of gaseous envelopes. We follow the
thermal evolution of newly formed super-Earths and discuss their atmospheric
mass loss due to disk dispersal, photoevaporation, core-cooling and collisions.
We conclude with a comparison of observations and theoretical predictions,
highlighting that even super-Earths that appear as barren rocky cores today
likely formed with primordial hydrogen and helium envelopes and discuss some
paths forward for the future.Comment: Invited review accepted for publication in the 'Handbook of
Exoplanets,' Planet Formation section, Springer Reference Works, Juan Antonio
Belmonte and Hans Deeg, Ed
Magnetic moments of charged hyperons
Measurements of the magnetic moments of the Ξ−, Σ+ and Σ− baryons are presented. The values found are μΞ−=−.69±.04, μΣ+=2.31±.027 and μΣ−=−.89±.14, in units μN. The Ξ− and Σ− results are final, while the Σ+ value is based on a preliminary analysis of about 22% of the data sample.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87403/2/58_1.pd
Treatment of Truncal Incompetence and Varicose Veins with a Single Administration of a New Polidocanol Endovenous Microfoam Preparation Improves Symptoms and Appearance
ObjectiveThis multicenter, parallel group study was designed to determine if a single administration of ≤15 mL of pharmaceutical-grade polidocanol endovenous microfoam (PEM, now approved in the United States as Varithena [polidocanol injectable foam], BTG International Ltd.) could alleviate symptoms and improve appearance of varicose veins in a typical population of patients with moderate to very severe symptoms of superficial venous incompetence and visible varicosities of the great saphenous vein (GSV) system.MethodsThe primary endpoint was patient-reported venous symptom improvement measured by change from baseline to Week 8 in 7-day average VVSymQ score. Co-secondary endpoints measured improvement in appearance of visible varicose veins from baseline to Week 8, as measured by the Independent Photography Review–Visible Varicose Veins (IPR-V3) and Patient Self-assessment of Visible Varicose Veins (PA-V3) scores. Patients were randomized to five groups: PEM 0.125% (control), 0.5%, 1%, 2%, or placebo. Adverse events (AEs) were recorded at each study visit. Tertiary endpoints measured duplex ultrasound response, changes in venous clinical severity score, and the modified Venous Insufficiency Epidemiological and Economic Study–Quality of Life/Symptoms.ResultsAt Week 8, VVSymQ scores for the pooled PEM group (0.5% + 1% + 2%; p < .0001) and individual dose concentrations (p < .001) were significantly superior to placebo. Mean changes from baseline to Week 8 in IPR-V3 and PA-V3 scores were significantly greater for pooled PEM than for placebo (p < .0001). Most AEs were mild and resolved without sequelae. No pulmonary emboli were reported.ConclusionsThis study demonstrated that a single administration of up to 15 mL of PEM is a safe, effective, and convenient treatment for the symptoms of superficial venous incompetence and the appearance of visible varicosities of the GSV system. Doses of 0.5%, 1%, and 2% PEM appear to have an acceptable risk-benefit ratio
Transit Timing and Duration Variations for the Discovery and Characterization of Exoplanets
Transiting exoplanets in multi-planet systems have non-Keplerian orbits which
can cause the times and durations of transits to vary. The theory and
observations of transit timing variations (TTV) and transit duration variations
(TDV) are reviewed. Since the last review, the Kepler spacecraft has detected
several hundred perturbed planets. In a few cases, these data have been used to
discover additional planets, similar to the historical discovery of Neptune in
our own Solar System. However, the more impactful aspect of TTV and TDV studies
has been characterization of planetary systems in which multiple planets
transit. After addressing the equations of motion and parameter scalings, the
main dynamical mechanisms for TTV and TDV are described, with citations to the
observational literature for real examples. We describe parameter constraints,
particularly the origin of the mass/eccentricity degeneracy and how it is
overcome by the high-frequency component of the signal. On the observational
side, derivation of timing precision and introduction to the timing diagram are
given. Science results are reviewed, with an emphasis on mass measurements of
transiting sub-Neptunes and super-Earths, from which bulk compositions may be
inferred.Comment: Revised version. Invited review submitted to 'Handbook of
Exoplanets,' Exoplanet Discovery Methods section, Springer Reference Works,
Juan Antonio Belmonte and Hans Deeg, Eds. TeX and figures may be found at
https://github.com/ericagol/TTV_revie
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