1,044 research outputs found
Behavior of Biaxially Loaded Slab-Column Connections with Shear Studs
Results are presented from four non-prestressed concrete slabcolumn connection subassemblies tested under simulated gravity
and earthquake-type loading. Each specimen consisted of a largescale first-story interior slab-column connection reinforced with
headed shear studs, loaded to a gravity-shear ratio of 50%, and
subjected to biaxial lateral displacements. The slabs, which were
nominally identical aside from the shear stud reinforcement design,
had a flexural reinforcement ratio in the column strip, based on
the effective depth, of 0.7%. Shear stud reinforcement in the test
specimens varied in terms of amount and spacing, both between
and within stud peripheral lines.
All four specimens exhibited drift capacities significantly lower
than shown by previous studies. Although the lateral strength of
the specimens was governed by the flexural capacity of the slab,
severe concrete degradation ultimately limited the drift capacity
of the connections. Signs of punching-related damage were first
observed during the cycle to 1.85% drift in each loading direction.
Test results suggest that the minimum amount of shear reinforcement required in Section 21.13.6 of ACI 318-11 when neither a drift
nor a combined shear-stress check is performed (vs ≥ 3.5√fc′, psi
[0.29√fc′, MPa]) is adequate for connections subjected to a gravity
shear ratio of up to 50% and resultant drifts from biaxial displacements of up to 2.0% if studs are spaced at less than 2d within the
first two peripheral lines. For larger drift demands, a maximum
stud spacing within the first three peripheral lines of 1.5d is
recommended.Network for Earthquake Engineering Simulation (NEES) Program (Grant No. 0936519
Calibration of cognitive tests to address the reliability paradox for decision-conflict tasks
Standard, well-established cognitive tasks that produce reliable effects in group comparisons also lead to unreliable measurement when assessing individual differences. This reliability paradox has been demonstrated in decision-conflict tasks such as the Simon, Flanker, and Stroop tasks, which measure various aspects of cognitive control. We aim to address this paradox by implementing carefully calibrated versions of the standard tests with an additional manipulation to encourage processing of conflicting information, as well as combinations of standard tasks. Over five experiments, we show that a Flanker task and a combined Simon and Stroop task with the additional manipulation produced reliable estimates of individual differences in under 100 trials per task, which improves on the reliability seen in benchmark Flanker, Simon, and Stroop data. We make these tasks freely available and discuss both theoretical and applied implications regarding how the cognitive testing of individual differences is carried out.</p
Role of Defect Interaction in Boundary Mobility and Cation Diffusivity of CeO 2
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65842/1/j.1151-2916.1994.tb04596.x.pd
Ice ages and butterflyfishes: Phylogenomics elucidates the ecological and evolutionary history of reef fishes in an endemism hotspot
For tropical marine species, hotspots of endemism occur in peripheral areas furthest from the center of diversity, but the evolutionary processes that lead to their origin remain elusive. We test several hypotheses related to the evolution of peripheral endemics by sequencing ultraconserved element (UCE) loci to produce a genome-scale phylogeny of 47 butterflyfish species (family Chaetodontidae) that includes all shallow water butterflyfish from the coastal waters of the Arabian Peninsula (i.e., Red Sea to Arabian Gulf) and their close relatives. Bayesian tree building methods produced a well-resolved phylogeny that elucidated the origins of butterflyfishes in this hotspots of endemism. We show that UCEs, often used to resolve deep evolutionary relationships, represent an important tool to assess the mechanisms underlying recently diverged taxa. Our analyses indicate that unique environmental conditions in the coastal waters of the Arabian Peninsula probably contributed to the formation of endemic butterflyfishes. Older endemic species are also associated with narrow versus broad depth ranges, suggesting that adaptation to deeper coral reefs in this region occurred only recently (<1.75Â Ma). Even though deep reef environments were drastically reduced during the extreme low sea level stands of glacial ages, shallow reefs persisted, and as such there was no evidence supporting mass extirpation of fauna in this region
Zirconium oxidation under high energy heavy ion irradiation
This paper concerns the study of zirconium oxidation under irradiation with
high energetic Xe ions. The irradiations were performed on the IRRSUD beam line
at GANIL (Caen). The oxygen partial pressure was fixed at 10 Pa and two
temperature conditions were used, either 480C reached by Joule effect
heating or 280C due to Xe energy deposition. Zirconia was fully
characterized by Rutherford Backscattering Spectrometry, Transmission Electron
Microscopy and Grazing Angle X-ray Diffraction. Apparent diffusion coefficients
of oxygen in ZrO2 were determined from these experiments by using a model which
takes into account a surface exchange between oxygen gas and the ZrO2 surface.
These results are compared with thermal oxidation data
The brain as 'immunoprecipitator' of serum autoantibodies against N-Methyl-D-Aspartate receptor subunit NR1
Autoantibodies (AB) against N-methyl-D-aspartate receptor subunit NR1 (NMDAR1) are highly seroprevalent in health and disease. Symptomatic relevance may arise upon compromised blood-brain barrier (BBB). However, it remained unknown whether circulating NMDAR1 AB appear in the cerebrospinal fluid (CSF). Of n5271 subjects with CSF-serum pairs, 26 were NMDAR1 AB seropositive, but only 1 was CSF positive. Contrariwise, tetanus AB (non-brain-binding) were present in serum and CSF of all subjects, with CSF levels higher upon BBB dysfunction. Translational mouse experiments proved the hypothesis that the brain acts as an 'immunoprecipitator'; simultaneous injection of NMDAR1 AB and the non-brain-binding green fluorescent protein AB resulted in high detectability of the former in brain and the latter in CSF
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Active assembly for large-scale manufacturing of integrated nanostructures.
Microtubules and motor proteins are protein-based biological agents that work cooperatively to facilitate the organization and transport of nanomaterials within living organisms. This report describes the application of these biological agents as tools in a novel, interdisciplinary scheme for assembling integrated nanostructures. Specifically, selective chemistries were used to direct the favorable adsorption of active motor proteins onto lithographically-defined gold electrodes. Taking advantage of the specific affinity these motor proteins have for microtubules, the motor proteins were used to capture polymerized microtubules out of suspension to form dense patterns of microtubules and microtubule bridges between gold electrodes. These microtubules were then used as biofunctionalized templates to direct the organization of functionalized nanocargo including single-walled carbon nanotubes and gold nanoparticles. This biologically-mediated scheme for nanomaterials assembly has shown excellent promise as a foundation for developing new biohybrid approaches to nanoscale manufacturing
Karyotype Variability and Inter-Population Genomic Differences in Freshwater Ostracods (Crustacea) Showing Geographical Parthenogenesis
Transitions from sexual to asexual reproduction are often associated with polyploidy and increased chromosomal plasticity in asexuals. We investigated chromosomes in the freshwater ostracod species Eucypris virens (Jurine, 1820), where sexual, asexual and mixed populations can be found. Our initial karyotyping of multiple populations from Europe and North Africa, both sexual and asexual, revealed a striking variability in chromosome numbers. This would suggest that chromosomal changes are likely to be accelerated in asexuals because the constraints of meiosis are removed. Hence, we employed comparative genomic hybridization (CGH) within and among sexual and asexual populations to get insights into E. virens genome arrangements. CGH disclosed substantial genomic imbalances among the populations analyzed, and three patterns of genome arrangement between these populations: 1. Only putative ribosomal DNA (rDNA)-bearing regions were conserved in the two populations compared indicating a high sequence divergence between these populations. This pattern is comparable with our findings at the interspecies level of comparison;2. Chromosomal regions were shared by both populations to a varying extent with a distinct copy number variation in pericentromeric and presumable rDNA-bearing regions. This indicates a different rate of evolution in repetitive sequences;3. A mosaic pattern of distribution of genomic material that can be explained as non-reciprocal genetic introgression and evidence of a hybrid origin of these individuals. We show an overall increased chromosomal dynamics in E. virens that is complementary with available phylogenetic and population genetic data reporting highly differentiated diploid sexual and asexual lineages with a wide variety of genetic backgrounds
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