321 research outputs found
Don't Believe The Hype!:White Lies of Conversational User Interface Creation Tools
The 2nd International Conference on Conversational User Interfaces (CUI 2020), Bilbao, Spain, 23-24 July 2020Following the initial hype and high expectations of conversational user interfaces (CUIs), a number of creation tools have emerged to simplify development of these complex systems. These have the potential to democratise and expand application development to those without programming skills. However, while such tools allow end-user developers to build language understanding and dialog management capability into a CUI application, actually fulfilling or executing an action still requires programmatic API integration. In this paper, we look at how CUI builders that claim to be ``no code required'' struggle to yield more than toy examples, with an aim to provoke the community to develop better tools for CUI creation.Trinity College Dublin (TCD
Radial fingering in a Hele-Shaw cell: a weakly nonlinear analysis
The Saffman-Taylor viscous fingering instability occurs when a less viscous
fluid displaces a more viscous one between narrowly spaced parallel plates in a
Hele-Shaw cell. Experiments in radial flow geometry form fan-like patterns, in
which fingers of different lengths compete, spread and split. Our weakly
nonlinear analysis of the instability predicts these phenomena, which are
beyond the scope of linear stability theory. Finger competition arises through
enhanced growth of sub-harmonic perturbations, while spreading and splitting
occur through the growth of harmonic modes. Nonlinear mode-coupling enhances
the growth of these perturbations with appropriate relative phases, as we
demonstrate through a symmetry analysis of the mode coupling equations. We
contrast mode coupling in radial flow with rectangular flow geometry.Comment: 36 pages, 5 figures, Latex, added references, to appear in Physica D
(1998
The value of paleoecology as an aid to monitoring ecosystems and landscapes, chiefly with reference to North America
Paleoecological indicators are examined as to their accuracy in reconstructing past biotic communities and environmental conditions, their utility in answering important questions about such communities and conditions, and the temporal and spatial scales over which they are effective. Next, environmental problems susceptible of paleoecological analysis are considered, as are the ecosystem and landscape properties that can be inferred from such an analysis. The usefulness of paleoecology in anticipating ecological surprises is then discussed. Finally, a set of conclusions and recommendations is presented
Quantifying the effects of commercial clam aquaculture on C and N cycling : an integrated ecosystem approach
Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Coastal and Estuarine Research Federation for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 39 (2016): 1746â1761, doi: 10.1007/s12237-016-0106-0.Increased interest in using bivalve cultivation to mitigate eutrophication requires a
comprehensive understanding of the net carbon (C) and nitrogen (N) budgets associated with
cultivation on an ecosystem scale. This study quantified C and N processes related to clam
(Mercenaria mercenaria) aquaculture in a shallow coastal environment (Cherrystone Inlet, VA)
where the industry has rapidly increased. Clam physiological rates were compared with basin-wide ecosystem fluxes including primary production, benthic nutrient regeneration, and
respiration. Although clam beds occupy only 3% of the ecosystemâs surface area, clams filtered
7-44% of the systemâs volume daily, consumed an annual average of 103% of the phytoplankton
production, creating a large flux of particulate C and N to the sediments. Annually, N
regenerated and C respired by clam and microbial metabolism in clam beds were ~3-fold and
~1.5-fold higher, respectively, than N and C removed through harvest. Due to the short water
residence time, the low watershed load, and the close vicinity of clam beds to the mouth of
Cherrystone Inlet, cultivated clams are likely subsidized by phytoplankton from the Chesapeake
Bay. Consequently, much of the N released by mineralization associated with clam cultivation is
ânewâ N as it would not be present in the system without bivalve facilitation. Macroalgae that are
fueled by the enhanced N regeneration from clams represents a eutrophying process resulting
from aquaculture. This synthesis demonstrates the importance of considering impacts of bivalve
aquaculture in an ecosystem context especially relative to the potential of bivalves to remove
nutrients and enhance C sinks.This work was supported by Virginia Sea Grant (NA10OAR4170085, #R/71515W, #R/715168), the NSF GK12 Fellowship (DGE-0840804), the Strategic Environmental Research and
Development Program â Defense Coastal/Estuarine Research Program Project SI-1413, and NSF
Virginia Coast Reserve LTER Project (DEB 0080381, DEB 0621014).2017-05-1
The Hartree limit of Born's ensemble for the ground state of a bosonic atom or ion
The non-relativistic bosonic ground state is studied for quantum N-body
systems with Coulomb interactions, modeling atoms or ions made of N "bosonic
point electrons" bound to an atomic point nucleus of Z "electron" charges,
treated in Born--Oppenheimer approximation. It is shown that the (negative)
ground state energy E(Z,N) yields the monotonically growing function (E(l N,N)
over N cubed). By adapting an argument of Hogreve, it is shown that its limit
as N to infinity for l > l* is governed by Hartree theory, with the rescaled
bosonic ground state wave function factoring into an infinite product of
identical one-body wave functions determined by the Hartree equation. The proof
resembles the construction of the thermodynamic mean-field limit of the
classical ensembles with thermodynamically unstable interactions, except that
here the ensemble is Born's, with the absolute square of the ground state wave
function as ensemble probability density function, with the Fisher information
functional in the variational principle for Born's ensemble playing the role of
the negative of the Gibbs entropy functional in the free-energy variational
principle for the classical petit-canonical configurational ensemble.Comment: Corrected version. Accepted for publication in Journal of
Mathematical Physic
Alteration of Retinal Rod Outer Segment Membrane Fluidity in a Rat Model of Smith-Lemli-Opitz Syndrome
Smith-Lemli-Opitz syndrome (SLOS) is caused by an inherited defect in the last step in cholesterol (Chol) biosynthesis, leading to abnormal accumulation of 7-dehydrocholesterol and decreased Chol levels. Progressive retinal degeneration occurs in an animal model of SLOS, induced by treating rats with AY9944, a selective inhibitor of the enzyme affected in SLOS. Here we evaluated alterations in the biochemical and physical properties of retinal rod outer segment (ROS) membranes in this animal model. At 1 month of AY9944 treatment, there were modest alterations in fatty acid composition, but no significant differences in cis-parinaric acid (cPA) spectroscopic parameters in ROS membranes from treated versus control rats. However, at 3 months, ROS docosahexaenoic acid (DHA) content was dramatically reduced, and cPA fluorescence anisotropy values were decreased, relative to controls. Also, 1, 6-diphenyl-1, 3, 5-hexatriene exhibited decreased rotational motion and increased orientational order in ROS membranes from 3 month-old AY9944-treated rats, relative to controls. No significant changes in protein:lipid ratios were observed; however, rhodopsin regenerability was compromised by 3 months of treatment. These findings are consistent with reduced ROS membrane fluidity in the SLOS rat model, relative to controls, primarily due to the dramatic reduction inmembraneDHA levels, rather than altered sterol composition
POLLEN CLUMPING AND WIND DISPERSAL IN AN INVASIVE ANGIOSPERM
Pollen dispersal is a fundamental aspect of plant reproductive biology that maintains connectivity between spatially separated populations. Pollen clumping, a characteristic feature of insect-pollinated plants, is generally assumed to be a detriment to wind pollination because clumps disperse shorter distances than do solitary pollen grains. Yet pollen clumps have been observed in dispersion studies of some widely distributed wind-pollinated species. We used Ambrosia artemisiifolia (common ragweed; Asteraceae), a successful invasive angiosperm, to investigate the effect of clumping on wind dispersal of pollen under natural conditions in a large field. Results of simultaneous measurements of clump size both in pollen shedding from male flowers and airborne pollen being dispersed in the atmosphere are combined with a transport model to show that rather than being detrimental, clumps may actually be advantageous for wind pollination. Initial clumps can pollinate the parent population, while smaller clumps that arise from breakup of larger clumps can cross-pollinate distant populations
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ATM-deficient thymic lymphoma is associated with aberrant tcrd rearrangement and gene amplification
Ataxia telangiectasia mutated (ATM) deficiency predisposes humans and mice to T lineage lymphomas with recurrent chromosome 14 translocations involving the T cell receptor α/ÎŽ (Tcra/d) locus. Such translocations have been thought to result from aberrant repair of DNA double-strand breaks (DSBs) during Tcra locus V(D)J recombination, and to require the Tcra enhancer (Eα) for Tcra rearrangement or expression of the translocated oncogene. We now show that, in addition to the known chromosome 14 translocation, ATM-deficient mouse thymic lymphomas routinely contain a centromeric fragment of chromosome 14 that spans up to the 5âČ boundary of the Tcra/d locus, at which position a 500-kb or larger region centromeric to Tcra/d is routinely amplified. In addition, they routinely contain a large deletion of the telomeric end of one copy of chromosome 12. In contrast to prior expectations, the recurrent translocations and amplifications involve V(D)J recombinationâinitiated breaks in the Tcrd locus, as opposed to the Tcra locus, and arise independently of the Eα. Overall, our studies reveal previously unexpected mechanisms that contribute to the oncogenic transformation of ATM-deficient T lineage cells
Surgeon Estimations of Acetabular Cup Orientation Using Intraoperative Fluoroscopic Imagining Are Unreliable.
BACKGROUND: Accurate acetabular cup orientation is associated with decreased revision rates and improved outcomes of primary total hip arthroplasty. This study assesses surgeon\u27s ability to estimate both the acetabular component inclination and anteversion angles via intraoperative fluoroscopy (IF) images.
METHODS: We surveyed orthopedic surgeons to estimate acetabular component inclination and anteversion based on 20 IF images of total hip arthroplasty through a direct anterior approach. Postoperative computed-tomography scans were used to calculate the true inclination and anteversion component angles. The absolute difference between the true and estimated values was calculated to determine the mean and standard deviation of the survey results. Interrater reliability was determined through interclass correlation coefficients.
RESULTS: A majority of surgeons preferred the direct anterior approach (83.3%) and utilized IF during surgery (70%). Surgeons surveyed were on average 5.9° away from the true value of inclination (standard deviation = 4.7) and 8.8° away from the true value of anteversion (standard deviation = 6.0). Respondents were within 5° of both inclination and anteversion in 19.7% of cases, and within 10° in 57.3% of cases. All surgeons were determined to have poor reliability in estimating anteversion (interclass correlation coefficient \u3c 0.5). Only 2 surgeons were determined to have moderate reliability when estimating inclination.
CONCLUSIONS: Surgeons, when solely relying on IF for the estimation of anteversion and inclination, are unreliable. Utilization of other techniques in conjunction with IF would improve observer reliability
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