1,506 research outputs found
Preference fusion and Condorcet's Paradox under uncertainty
Facing an unknown situation, a person may not be able to firmly elicit
his/her preferences over different alternatives, so he/she tends to express
uncertain preferences. Given a community of different persons expressing their
preferences over certain alternatives under uncertainty, to get a collective
representative opinion of the whole community, a preference fusion process is
required. The aim of this work is to propose a preference fusion method that
copes with uncertainty and escape from the Condorcet paradox. To model
preferences under uncertainty, we propose to develop a model of preferences
based on belief function theory that accurately describes and captures the
uncertainty associated with individual or collective preferences. This work
improves and extends the previous results. This work improves and extends the
contribution presented in a previous work. The benefits of our contribution are
twofold. On the one hand, we propose a qualitative and expressive preference
modeling strategy based on belief-function theory which scales better with the
number of sources. On the other hand, we propose an incremental distance-based
algorithm (using Jousselme distance) for the construction of the collective
preference order to avoid the Condorcet Paradox.Comment: International Conference on Information Fusion, Jul 2017, Xi'an,
Chin
Nuclear magnetic resonance spectroscopy: Abnormal splitting of ethyl groups due to molecular asymmetry
Nuclear magnetic resonance (n.m.r.) spectroscopy provides an excellent means for qualitative identification of ethyl groups by use of the familiar three-four pattern of spin-spin splitting (1). It has been observed previously (2) that the methylene protons of systems of the type R-CH2-CR1R2R3 (where R1 can be the same as R or different) may be magnetically nonequivalent and display AB rather than A2-type spectra (3). We now wish to report several examples of this type of behavior with ethyl groups, particularly ethoxy groups, knowledge of which could be important to anyone using n.m.r. for organic qualitative analysis
Development and field evaluation of an online monitor for near-continuous measurement of iron, manganese, and chromium in coarse airborne particulate matter (PM)
A novel air sampling monitor was developed for near-continuous (i.e., 2-h time resolution) measurement of iron (Fe), manganese (Mn), and chromium (Cr) concentrations in ambient coarse particulate matter (PM) (i.e., PM10â2.5). The developed monitor consists of two modules: (1) the coarse PM collection module, utilizing two virtual impactors (VIs) connected to a modified BioSampler to collect ambient coarse PM into aqueous slurry samples; (2) the metal concentration measurement module, which quantifies the light absorption of colored complexes formed through the reactions between the soluble and solubilized target metals and pertinent analytical reagents in the collected slurries using a micro volume flow cell (MVFC) coupled with UV/VIS spectrophotometry. The developed monitor was deployed in the field for continuous ambient PM collection and measurements from January to April 2016 to evaluate its performance and reliability. Overall, the developed monitor could achieve accurate and reliable measurements of the trace metals Fe, Mn, and Cr over long sampling periods, based on the agreement between the metal concentrations measured via this online monitor and off-line parallel measurements obtained using filter samplers. Based on our results, it can be concluded that the developed monitor is a promising technology for near-continuous measurements of metal concentrations in ambient coarse PM. Moreover, this monitor can be readily configured to measure the speciation (i.e., water-soluble portion as well as specific oxidation states) of these metal species. These unique abilities are essential tools in investigations of sources and atmospheric processes influencing the concentrations of these redox-active metals in coarse PM. Copyright © 2016 American Association for Aerosol Research © 2016 American Association for Aerosol Research
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Physical, chemical, and toxicological characteristics of particulate emissions from current technology gasoline direct injection vehicles
Neither dust nor black carbon causing apparent albedo decline in Greenland\u27s dry snow zone: Implications for MODIS C5 surface reflectance
Remote sensing observations suggest Greenland ice sheet (GrIS) albedo has declined since 2001, even in the dry snow zone. We seek to explain the apparent dry snow albedo decline. We analyze samples representing 2012â2014 snowfall across NW Greenland for black carbon and dust light-absorbing impurities (LAI) and model their impacts on snow albedo. Albedo reductions due to LAI are small, averaging 0.003, with episodic enhancements resulting in reductions of 0.01â0.02. No significant increase in black carbon or dust concentrations relative to recent decades is found. Enhanced deposition of LAI is not, therefore, causing significant dry snow albedo reduction or driving melt events. Analysis of Collection 5 Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data indicates that the decline and spectral shift in dry snow albedo contains important contributions from uncorrected Terra sensor degradation. Though discrepancies are mostly below the stated accuracy of MODIS products, they will require revisiting some prior conclusions with C6 data
Plausibility functions and exact frequentist inference
In the frequentist program, inferential methods with exact control on error
rates are a primary focus. The standard approach, however, is to rely on
asymptotic approximations, which may not be suitable. This paper presents a
general framework for the construction of exact frequentist procedures based on
plausibility functions. It is shown that the plausibility function-based tests
and confidence regions have the desired frequentist properties in finite
samples---no large-sample justification needed. An extension of the proposed
method is also given for problems involving nuisance parameters. Examples
demonstrate that the plausibility function-based method is both exact and
efficient in a wide variety of problems.Comment: 21 pages, 5 figures, 3 table
Lipooligosaccharide Structure is an Important Determinant in the Resistance of Neisseria Gonorrhoeae to Antimicrobial Agents of Innate Host Defense
The strict human pathogen Neisseria gonorrhoeae has caused the sexually transmitted infection termed gonorrhea for thousands of years. Over the millennia, the gonococcus has likely evolved mechanisms to evade host defense systems that operate on the genital mucosal surfaces in both males and females. Past research has shown that the presence or modification of certain cell envelope structures can significantly impact levels of gonococcal susceptibility to host-derived antimicrobial compounds that bathe genital mucosal surfaces and participate in innate host defense against invading pathogens. In order to facilitate the identification of gonococcal genes that are important in determining levels of bacterial susceptibility to mediators of innate host defense, we used the Himar I mariner in vitro mutagenesis system to construct a transposon insertion library in strain F62. As proof of principle that this strategy would be suitable for this purpose, we screened the library for mutants expressing decreased susceptibility to the bacteriolytic action of normal human serum (NHS). We found that a transposon insertion in the lgtD gene, which encodes an N-acetylgalactosamine transferase involved in the extension of the α-chain of lipooligosaccharide (LOS), could confer decreased susceptibility of strain F62 to complement-mediated killing by NHS. By complementation and chemical analyses, we demonstrated both linkage of the transposon insertion to the NHS-resistance phenotype and chemical changes in LOS structure that resulted from loss of LgtD production. Further truncation of the LOS α-chain or loss of phosphoethanolamine (PEA) from the lipid A region of LOS also impacted levels of NHS-resistance. PEA decoration of lipid A also increased gonococcal resistance to the model cationic antimicrobial polymyxin B. Taken together, we conclude that the Himar I mariner in vitro mutagenesis procedure can facilitate studies on structures involved in gonococcal pathogenesis
Object preference by walking fruit flies, Drosophila melanogaster, is mediated by vision and graviperception
Walking fruit flies, Drosophila melanogaster, use visual information to orient towards salient objects in their environment,
presumably as a search strategy for finding food, shelter or other resources. Less is known, however, about the role of vision or
other sensory modalities such as mechanoreception in the evaluation of objects once they have been reached. To study the role
of vision and mechanoreception in exploration behavior, we developed a large arena in which we could track individual fruit flies
as they walked through either simple or more topologically complex landscapes. When exploring a simple, flat environment
lacking three-dimensional objects, flies used visual cues from the distant background to stabilize their walking trajectories. When
exploring an arena containing an array of cones, differing in geometry, flies actively oriented towards, climbed onto, and explored
the objects, spending most of their time on the tallest, steepest object. A flyâs behavioral response to the geometry of an object
depended upon the intrinsic properties of each object and not a relative assessment to other nearby objects. Furthermore, the
preference was not due to a greater attraction towards tall, steep objects, but rather a change in locomotor behavior once a fly
reached and explored the surface. Specifically, flies are much more likely to stop walking for long periods when they are perched
on tall, steep objects. Both the vision system and the antennal chordotonal organs (Johnstonâs organs) provide sufficient
information about the geometry of an object to elicit the observed change in locomotor behavior. Only when both these sensory
systems were impaired did flies not show the behavioral preference for the tall, steep objects
Towards a viable grand unified model with and GeV
We present a model based on the gauge group
SU(2)SU(2)SU(4) with gauge couplings that are found to
be unified at a scale near the string unification scale. The model breaks
to the minimal supersymmetric standard model at a scale GeV,
which is instrumental in producing a neutrino in a mass range that can serve as
hot dark matter and this scale can also solve the strong CP problem via
Peccei-Quinn (PQ) mechanism with an invisible harmless invisible axion. We show
how this model can accommodate low and high values of and ``exotic"
representations that often occur in string derived models. We show that this
model has lepton flavor violation which can lead to processes which are one or
two orders of magnitude below the current experimental limits.Comment: 16 pages(Latex), 1 PS Figures (uuencoded, epsf.tex), Typo in the
archive title (not in the paper), no change in pape
Widespread Receptivity to Neuropeptide PDF throughout the Neuronal Circadian Clock Network of Drosophila Revealed by Real-Time Cyclic AMP Imaging
SummaryThe neuropeptide PDF is released by sixteen clock neurons in Drosophila and helps maintain circadian activity rhythms by coordinating a network of âŒ150 neuronal clocks. Whether PDF acts directly on elements of this neural network remains unknown. We address this question by adapting Epac1-camps, a genetically encoded cAMP FRET sensor, for use in the living brain. We find that a subset of the PDF-expressing neurons respond to PDF with long-lasting cAMP increases and confirm that such responses require the PDF receptor. In contrast, an unrelated Drosophila neuropeptide, DH31, stimulates large cAMP increases in all PDF-expressing clock neurons. Thus, the network of âŒ150 clock neurons displays widespread, though not uniform, PDF receptivity. This work introduces a sensitive means of measuring cAMP changes in a living brain with subcellular resolution. Specifically, it experimentally confirms the longstanding hypothesis that PDF is a direct modulator of most neurons in the Drosophila clock network
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