8,260 research outputs found
Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) Observed Feeding on Chamaesaracha sp. in Eastern Colorado.
Egg, larval, and adult life stages of Colorado potato beetle, Leptinotarsa decemlineata (Say), were observed feeding on or attached to a previously undocumented host plant belonging to the genus Chamaesaracha in eastern Colorado on July 2017. At one site, L. decemlineata were more abundant on Chamaesaracha sp. than the accepted ancestral host plant, Solanum rostratum (Dunal). While future studies should confirm the ancestral status of the observed L. decemlineata and suitability of Chamaesaracha sp. for completion of development, our observations suggest a need for further characterization of the ancestral host range of L. decemlineata
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Multicomponent metal-organic framework membranes for advanced functional composites.
The diverse chemical and structural properties of metal-organic frameworks (MOFs) make them attractive for myriad applications, but their native powder form is limiting for industrial implementation. Composite materials of MOFs hold promise as a means of exploiting MOF properties in engineered forms for real-world applications. While interest in MOF composites is growing, research to date has largely focused on utilization of single MOF systems. The vast number of different MOF structures provides ample opportunity to mix and match distinct MOF species in a single composite to prepare multifunctional systems. In this work, we describe the preparation of three types of multi-MOF composites with poly(vinylidene fluoride) (PVDF): (1) co-cast MOF MMMs, (2) mixed MOF MMMs, and (3) multilayer MOF MMMs. Finally, MOF MMMs are explored as catalytic membrane reactors for chemical transformations
Attosecond time-scale multi-electron collisions in the Coulomb four-body problem: traces in classical probability densities
In the triple ionization of the Li ground state by single photon absorption
the three electrons escape to the continuum mainly through two collision
sequences with individual collisions separated by time intervals on the
attosecond scale. We investigate the traces of these two collision sequences in
the classical probability densities. We show that each collision sequence has
characteristic phase space properties which distinguish it from the other.
Classical probability densities are the closest analog to quantum mechanical
densities allowing our results to be directly compared to quantum mechanical
results.Comment: 9 pages, 10 figure
Outcome Prediction for Unipolar Depression
Although effective drug and non-drug treatment for unipolar depressive illness exist, different individuals respond differently to different treatments. It is not uncommon for a given patient to lw switched several times from one treatment to another until an effective remedy for that particular patient is found. This process is costly in terms of time, money and suffering. It is thus desirable to determine at the outset the likdy response of a patient to the available treatments, so that the optimal one can be selected. Although prior attempts at outcome prediction with linear regression models have failed, recent work on this problem has indicated that the nonlinear predictive techniques of backpropagation and quadratic regression call account for a significant proportion of the variance in the data. The present research applies the nonlinear predictive technique of kernel regression to this problcrn, and employs cross-validation to test the ability of the resulting model to extract, from extremely noisy dinical data, information with predictive value. The importance of comparison with a suitable null hypothesis is illustrated.Office of Naval Research (N00014-95-1-0409
Free recall test experience potentiates strategy-driven effects of value on memory.
People tend to show better memory for information that is deemed valuable or important. By one mechanism, individuals selectively engage deeper, semantic encoding strategies for high value items (Cohen, Rissman, Suthana, Castel, & Knowlton, 2014). By another mechanism, information paired with value or reward is automatically strengthened in memory via dopaminergic projections from midbrain to hippocampus (Shohamy & Adcock, 2010). We hypothesized that the latter mechanism would primarily enhance recollection-based memory, while the former mechanism would strengthen both recollection and familiarity. We also hypothesized that providing interspersed tests during study is a key to encouraging selective engagement of strategies. To test these hypotheses, we presented participants with sets of words, and each word was associated with a high or low point value. In some experiments, free recall tests were given after each list. In all experiments, a recognition test was administered 5 minutes after the final word list. Process dissociation was accomplished via remember/know judgments at recognition, a recall test probing both item memory and memory for a contextual detail (word plurality), and a task dissociation combining a recognition test for plurality (intended to probe recollection) with a speeded item recognition test (to probe familiarity). When recall tests were administered after study lists, high value strengthened both recollection and familiarity. When memory was not tested after each study list, but rather only at the end, value increased recollection but not familiarity. These dual process dissociations suggest that interspersed recall tests guide learners' use of metacognitive control to selectively apply effective encoding strategies. (PsycINFO Database Recor
The oxygen-II luminosity density of the Universe
Equivalent widths of [OII] 3727 A lines are measured in 375 faint galaxy
spectra taken as part of the Caltech Faint Galaxy Redshift Survey centered on
the Hubble Deep Field. The sensitivity of the survey spectra to the [OII] line
is computed as a function of magnitude, color and redshift. The luminosity
function of galaxies in the [OII] line and the integrated luminosity density of
the Universe in the [OII] line are computed as a function of redshift. It is
found that the luminosity density in the [OII] line was a factor of ~10 higher
at redshifts z~1 than it is at the present day. The simplest interpretation is
that the star formation rate density of the Universe has declined dramatically
since z~1.Comment: accepted for publication in Ap
Identification of a WNT5A-Responsive Degradation Domain in the Kinesin Superfamily Protein KIF26B.
Noncanonical WNT pathways function independently of the β-catenin transcriptional co-activator to regulate diverse morphogenetic and pathogenic processes. Recent studies showed that noncanonical WNTs, such as WNT5A, can signal the degradation of several downstream effectors, thereby modulating these effectors' cellular activities. The protein domain(s) that mediates the WNT5A-dependent degradation response, however, has not been identified. By coupling protein mutagenesis experiments with a flow cytometry-based degradation reporter assay, we have defined a protein domain in the kinesin superfamily protein KIF26B that is essential for WNT5A-dependent degradation. We found that a human disease-causing KIF26B mutation located at a conserved amino acid within this domain compromises the ability of WNT5A to induce KIF26B degradation. Using pharmacological perturbation, we further uncovered a role of glycogen synthase kinase 3 (GSK3) in WNT5A regulation of KIF26B degradation. Lastly, based on the identification of the WNT5A-responsive domain, we developed a new reporter system that allows for efficient profiling of WNT5A-KIF26B signaling activity in both somatic and stem cells. In conclusion, our study identifies a new protein domain that mediates WNT5A-dependent degradation of KIF26B and provides a new tool for functional characterization of noncanonical WNT5A signaling in cells
On Toroidal Horizons in Binary Black Hole Inspirals
We examine the structure of the event horizon for numerical simulations of
two black holes that begin in a quasicircular orbit, inspiral, and finally
merge. We find that the spatial cross section of the merged event horizon has
spherical topology (to the limit of our resolution), despite the expectation
that generic binary black hole mergers in the absence of symmetries should
result in an event horizon that briefly has a toroidal cross section. Using
insight gained from our numerical simulations, we investigate how the choice of
time slicing affects both the spatial cross section of the event horizon and
the locus of points at which generators of the event horizon cross. To ensure
the robustness of our conclusions, our results are checked at multiple
numerical resolutions. 3D visualization data for these resolutions are
available for public access online. We find that the structure of the horizon
generators in our simulations is consistent with expectations, and the lack of
toroidal horizons in our simulations is due to our choice of time slicing.Comment: Submitted to Phys. Rev.
Enhanced aging properties of HKUST-1 in hydrophobic mixed-matrix membranes for ammonia adsorption.
Metal-organic frameworks (MOFs) in their free powder form have exhibited superior capacities for many gases when compared to other materials, due to their tailorable functionality and high surface areas. Specifically, the MOF HKUST-1 binds small Lewis bases, such as ammonia, with its coordinatively unsaturated copper sites. We describe here the use of HKUST-1 in mixed-matrix membranes (MMMs) prepared from polyvinylidene difluoride (PVDF) for the removal of ammonia gas. These MMMs exhibit ammonia capacities similar to their hypothetical capacities based on the weight percent of HKUST-1 in each MMM. HKUST-1 in its powder form is unstable toward humid conditions; however, upon exposure to humid environments for prolonged periods of time, the HKUST-1 MMMs exhibit outstanding structural stability, and maintain their ammonia capacity. Overall, this study has achieved all of the critical and combined elements for real-world applications of MOFs: high MOF loadings, fully accessible MOF surfaces, enhanced MOF stabilization, recyclability, mechanical stability, and processability. This study is a critical step in advancing MOFs to a stable, usable, and enabling technology
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