1,819 research outputs found
Pre-Figurative Structures for Social Connection
The world has many structures that foster social connection. Especially in the age of the internet, there are many off and online worlds that do so. Alternative festivals, temporary communities and electoral guerrilla theater organized online and practiced offline are all potential ways to prefigure the world we want to live in. Together, the FEAST team created physically and socially intelligent structures that facilitate cooperation, emotional release and transcend the expectations of architecture and infrastructure as fixed, emboldening viewers to become participants.http://deepblue.lib.umich.edu/bitstream/2027.42/169558/1/Honors_Capstone_Socially_Connected_Structures.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/169558/2/Honors_Capstone_Socially_Connected_Structures.ppt
The Role of Demographic History and Selection in Shaping Genetic Diversity of the Galápagos Penguin (Spheniscus mendiculus)
Although many studies have documented the effects of demographic bottlenecks on the genetic diversity of natural populations, there is conflicting evidence of the roles that genetic drift and selection may play in driving changes in genetic variation at adaptive loci. We analyzed genetic variation at microsatellite and mitochondrial loci in conjunction with an adaptive MHC class II locus in the Galápagos penguin (Spheniscus mendiculus), a species that has undergone serial demographic bottlenecks associated with El Niño events through its evolutionary history. We compared levels of variation in the Galápagos penguin to those of its congener, the Magellanic penguin (Spheniscus magellanicus), which has consistently maintained a large population size and thus was used as a non-bottlenecked control. The comparison of neutral and adaptive markers in these two demographically distinct species allowed assessment of the potential role of balancing selection in maintaining levels of MHC variation during bottleneck events. Our analysis suggests that the lack of genetic diversity at both neutral and adaptive loci in the Galápagos penguin likely resulted from its restricted range, relatively low abundance, and history of demographic bottlenecks. The Galápagos penguin revealed two MHC alleles, one mitochondrial haplotype, and six alleles across five microsatellite loci, which represents only a small fraction of the diversity detected in Magellanic penguins. Despite the decreased genetic diversity in the Galápagos penguin, results revealed signals of balancing selection at the MHC, which suggest that selection can mitigate some of the effects of genetic drift during bottleneck events. Although Galápagos penguin populations have persisted for a long time, increased frequency of El Niño events due to global climate change, as well as the low diversity exhibited at immunological loci, may put this species at further risk of extinction
Auditory statistical learning in children: Novel insights from an online measure
Nonadjacent dependency learning is thought to be a fundamental skill for syntax acquisition and often assessed via an offline grammaticality judgment measure. Asking judgments of children is problematic, and an offline task is suboptimal as it reflects only the outcome of the learning process, disregarding information on the learning trajectory. Therefore, and following up on recent methodological advancements in the online measurement of nonadjacent dependency learning in adults, the current study investigates if the recording of response times can be used to establish nonadjacent dependency learning in children. Forty-six children (mean age: 7.3 years) participated in a child-friendly adaptation of a nonadjacent dependency learning experiment (LĂłpez-Barroso, Cucurell, RodrĂguez-Fornells, & de Diego-Balaguer, 2016). They were exposed to an artificial language containing items with and without nonadjacent dependencies while their response times (online measure) were measured. After exposure, grammaticality judgments (offline measure) were collected. The results show that children are sensitive to nonadjacent dependencies, when using the online measure (the results of our offline measure did not provide evidence of learning). We therefore conclude that future studies can use online response time measures (perhaps in addition to the offline grammaticality judgments) to further investigate nonadjacent dependency learning in children
On the Field Equations of Kaluza's Theory
The field equations of the original Kaluza's theory are analyzed and it is
shown that they lead to modification of Einstein's equations. The appearing
extra energy-momentum tensor is studied and an example is given where this
extra energy-momentum tensor is shown to allow four-dimensional Schwarzschild
geometry to accommodate electrostatics. Such deviation from Reissner-Nordstrom
geometry can account for the interpretation of Schwarzschild geometry as
resulting not from mass only, but from the combined effects of mass and
electric charge, even electric charge alone.Comment: 14 pages, two sections added and title changed. To appear in Physics
Letters
Joint models with multiple longitudinal outcomes and a time-to-event outcome: a corrected two-stage approach
Joint models for longitudinal and survival data have gained a lot of attention in recent years, with the development of myriad extensions to the basic model, including those which allow for multivariate longitudinal data, competing risks and recurrent events. Several software packages are now also available for their implementation. Although mathematically straightforward, the inclusion of multiple longitudinal outcomes in the joint model remains computationally difficult due to the large number of random effects required, which hampers the practical application of this extension. We present a novel approach that enables the fitting of such models with more realistic computational times. The idea behind the approach is to split the estimation of the joint model in two steps: estimating a multivariate mixed model for the longitudinal outcomes and then using the output from this model to fit the survival submodel. So-called two-stage approaches have previously been proposed and shown to be biased. Our approach differs from the standard version, in that we additionally propose the application of a correction factor, adjusting the estimates obtained such that they more closely resemble those we would expect to find with the multivariate joint model. This correction is based on importance sampling ideas. Simulation studies show that this corrected two-stage approach works satisfactorily, eliminating the bias while maintaining substantial improvement in computational time, even in more difficult settings
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Validation of Urban Concentrations and Their Diurnal and Seasonal Variations Observed from the SCIAMACHY and OMI Sensors Using In Situ Surface Measurements in Israeli Cities
We compare a full-year (2006) record of surface air concentrations measured in Israeli cities to coinciding retrievals of tropospheric columns from satellite sensors (SCIAMACHY aboard ENVISAT and OMI aboard Aura). This provides a large statistical data set for validation of satellite measurements in urban air, where validation is difficult yet crucial for using these measurements to infer emissions by inverse modeling. Assuming that is well-mixed throughout the boundary layer (BL), and using observed average seasonal boundary layer heights, near-surface concentrations are converted into BL columns. The agreement between OMI and (13:45) BL columns (slope=0.93, n=542), and the comparable results at 10:00 h for SCIAMACHY, allow a validation of the seasonal, weekly, and diurnal cycles in satellite-derived . OMI and BL columns show consistent seasonal cycles (winter 1.6–2.7× higher than summer). BL and coinciding OMI columns both show a strong weekly cycle with 45–50% smaller columns on Saturday relative to the weekday mean, reflecting the reduced weekend activity, and validating the weekly cycle observed from space. The diurnal difference between SCIAMACHY (10:00) and OMI (13:45) is maximum in summer when SCIAMACHY is up to 40% higher than OMI, and minimum in winter when OMI slightly exceeds SCIAMACHY. A similar seasonal variation in the diurnal difference is found in the source region of Cairo. The surface measurements in Israel cities confirm this seasonal variation in the diurnal cycle. Using simulations from a global 3-D chemical transport model (GEOS-Chem), we show that this seasonal cycle can be explained by a much stronger photochemical loss of in summer than in winter.Engineering and Applied Science
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