192 research outputs found
Anomalous Roughening of Viscous Fluid Fronts in Spontaneous Imbibition
We report experiments on spontaneous imbibition of a viscous fluid by a model
porous medium in the absence of gravity. The average position of the interface
satisfies Washburn's law. Scaling of the interface fluctuations provides a
dynamic exponent z \simeq 3, indicative of global dynamics driven by capillary
forces. The complete set of exponents clearly shows that interfaces are not
self-affine, exhibiting distinct local and global scaling, both for time
(b=0.64\pm 0.02, b* =0.33 \pm 0.03) and space (a=1.94 \pm 0.20, a_loc=0.94 \pm
0.10). These values are compatible with an intrinsic anomalous scaling
scenario.Comment: 4 pages, 5 figure
When high similarity copycats lose and moderate similarity copycats gain: The impact of comparative evaluation
Copycats imitate features of leading brands to free ride on their equity. The prevailing belief is that the more similar copycats are to the leader brand, the more positive their evaluation is, and thus the more they free ride. Three studies demonstrate when the reverse holds true: Moderate-similarity copycats are actually evaluated more positively than high-similarity copycats when evaluation takes place comparatively, such as when the leader brand is present rather than absent. The results demonstrate that blatant copycats can be less and subtle copycats can be more perilous than is commonly believed. This finding has implications for marketing theory and practice and trademark law
Limits on Stellar and Planetary Companions in Microlensing Event OGLE-1998-BUL-14
We present the PLANET photometric data set for \ob14, a high magnification
() event alerted by the OGLE collaboration toward the
Galactic bulge in 1998. The PLANET data set consists a total of 461 I-band and
139 band points, the majority of which was taken over a three month period.
The median sampling interval during this period is about 1 hour, and the
scatter over the peak of the event is 1.5%. The excellent data
quality and high maximum magnification of this event make it a prime candidate
to search for the short duration, low amplitude perturbations that are
signatures of a planetary companion orbiting the primary lens. The observed
light curve for \ob14 is consistent with a single lens (no companion) within
photometric uncertainties. We calculate the detection efficiency of the light
curve to lensing companions as a function of the mass ratio and angular
separation of the two components. We find that companions of mass ratio are ruled out at the 95% confidence level for projected separations
between 0.4-2.4 \re, where \re is the Einstein ring radius of the primary
lens. Assuming that the primary is a G-dwarf with \re\sim3 {\rm AU} our
detection efficiency for this event is for a companion with the mass
and separation of Jupiter and for a companion with the mass and
separation of Saturn. Our efficiencies for planets like those around Upsilon
And and 14 Her are > 75%.Comment: Data available at http://www.astro.rug.nl/~planet/planetpapers.html
20 pages, 10 figures. Minor changes. ApJ, accepte
A Complete Set of Solutions For Caustic-Crossing Binary Microlensing Events
We present a method to analyze binary-lens microlensing light curves with one
well-sampled fold caustic crossing. In general, the surface of chi^2 shows
extremely complicated behavior over the 9-parameter space that characterizes
binary lenses. This makes it difficult to systematically search the space and
verify that a given local minimum is a global minimum. We show that for events
with well-monitored caustics, the caustic-crossing region can be isolated from
the rest of the light curve and easily fit to a 5-parameter function. Four of
these caustic-crossing parameters can then be used to constrain the search in
the larger 9-parameter space. This allows a systematic search for all solutions
and thus identification of all local minima. We illustrate this technique using
the PLANET data for MACHO 98-SMC-1, an excellent and publicly available
caustic-crossing data set. We show that a very broad range of parameter
combinations are compatible with the PLANET data set, demonstrating that
observations of binary-lens lightcurves with sampling of only one caustic
crossing do not yield unique solutions. The corollary to this is that the time
of the second caustic crossing cannot be reliably predicted on the basis of
early data including the first caustic crossing alone. We investigate the
requirements for determination of a unique solution and find that occasional
observations of the first caustic crossing may be sufficient to derive a
complete solution.Comment: 31 pages + 8 figures + 2 table
Structure-guided microbial targeting of antistaphylococcal prodrugs
Carboxy ester prodrugs are widely employed to increase oral absorption and potency of phosphonate antibiotics. Prodrugging can mask problematic chemical features that prevent cellular uptake and may enable tissue-specific compound delivery. However, many carboxy ester promoieties are rapidly hydrolyzed by serum esterases, limiting their therapeutic potential. While carboxy ester-based prodrug targeting is feasible, it has seen limited use in microbes as microbial esterase-specific promoieties have not been described. Here we identify the bacterial esterases, GloB and FrmB, that activate carboxy ester prodrugs i
The immunopeptidome landscape associated with T cell infiltration, inflammation and immune editing in lung cancer.
One key barrier to improving efficacy of personalized cancer immunotherapies that are dependent on the tumor antigenic landscape remains patient stratification. Although patients with CD3 <sup>+</sup> CD8 <sup>+</sup> T cell-inflamed tumors typically show better response to immune checkpoint inhibitors, it is still unknown whether the immunopeptidome repertoire presented in highly inflamed and noninflamed tumors is substantially different. We surveyed 61 tumor regions and adjacent nonmalignant lung tissues from 8 patients with lung cancer and performed deep antigen discovery combining immunopeptidomics, genomics, bulk and spatial transcriptomics, and explored the heterogeneous expression and presentation of tumor (neo)antigens. In the present study, we associated diverse immune cell populations with the immunopeptidome and found a relatively higher frequency of predicted neoantigens located within HLA-I presentation hotspots in CD3 <sup>+</sup> CD8 <sup>+</sup> T cell-excluded tumors. We associated such neoantigens with immune recognition, supporting their involvement in immune editing. This could have implications for the choice of combination therapies tailored to the patient's mutanome and immune microenvironment
OGLE-2005-BLG-153: Microlensing Discovery and Characterization of A Very Low Mass Binary
The mass function and statistics of binaries provide important diagnostics of
the star formation process. Despite this importance, the mass function at low
masses remains poorly known due to observational difficulties caused by the
faintness of the objects. Here we report the microlensing discovery and
characterization of a binary lens composed of very low-mass stars just above
the hydrogen-burning limit. From the combined measurements of the Einstein
radius and microlens parallax, we measure the masses of the binary components
of and . This discovery
demonstrates that microlensing will provide a method to measure the mass
function of all Galactic populations of very low mass binaries that is
independent of the biases caused by the luminosity of the population.Comment: 6 pages, 3 figures, 1 tabl
H-alpha Equivalent Width Variations across the Face of a Microlensed K Giant in the Galactic Bulge
We present VLT FORS1 spectroscopy that temporally resolves the second caustic
crossing of the Bulge K giant source of microlensing event EROS 2000-BLG-5, the
first time this has been accomplished for several phases of a caustic transit.
The ~1 angstrom H-alpha equivalent width of the source star increases slightly
as the center of the star egresses the caustic and then plummets by 30% during
the final limb crossing. These changes are not seen in contemporaneous spectra
of control stars in the FORS1 slit, but are qualitatively consistent with
expectations from stellar atmosphere models as the caustic differentially
magnifies different portions of the stellar face of the target. Observations
such as these in a variety of stellar lines are equivalent to atmospheric
tomography and are expected to provide a direct test of stellar models.Comment: 15 pages, including 1 table and 4 figures. As accepted by ApJ
Letters, vol 55
- …