22,743 research outputs found
Quartification On An Orbifold
We investigate quartification models in five dimensions, with the fifth
dimension forming an orbifold. The orbifold construction
is combined with a boundary Higgs sector to break the quartified gauge group
directly to a group which is operative at the electroweak
scale. We consider and , where
is the standard model gauge group, and find that unification occurs only when
the remnant leptonic colour symmetry remains unbroken.
Furthermore, the demands of a realistic low energy fermion spectrum specify a
unique symmetry breaking route for the unifying case of . We contrast this with four dimensional quartification models where
unification may be achieved via a number of different symmetry breaking routes
both with and without the remnant symmetry. The boundary Higgs
sector of our model may be decoupled to achieve a Higgsless limit and we show
that the electroweak Higgs doublet may be identified as the fifth component of
a higher dimensional gauge field.Comment: 14 pages, misprint corrected, matches PRD versio
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2019-nCoV: The Identify-Isolate-Inform (3I) Tool Applied to a Novel Emerging Coronavirus
2019 Novel Coronavirus (2019-nCoV) is an emerging infectious disease closely related to MERS-CoV and SARS-CoV that was first reported in Wuhan City, Hubei Province, China in December 2019. As of January 2020, cases of 2019-nCoV are continuing to be reported in other Eastern Asian countries as well as in the United States, Europe, Australia, and numerous other countries. An unusually high volume of domestic and international travel corresponding to the beginning of the 2020 Chinese New Year complicated initial identification and containment of infected persons. Due to the rapidly rising number of cases and reported deaths, all countries should be considered at risk of imported 2019-nCoV. Therefore, it is essential for prehospital, clinic, and emergency department personnel to be able to rapidly assess 2019-nCoV risk and take immediate actions if indicated. The Identify-Isolate-Inform (3I) tool, originally conceived for the initial detection and management of Ebola virus and later adjusted for other infectious agents, can be adapted for any emerging infectious disease. This paper reports a modification of the 3I tool for use in the initial detection and management of patients under investigation for 2019-nCoV. After initial assessment for symptoms and epidemiological risk factors, including travel to affected areas and exposure to confirmed 2019-nCoV patients within 14 days, patients are classified in a risk-stratified system. Upon confirmation of a suspected 2019-nCoV case, affected persons must immediately be placed in airborne infection isolation and the appropriate public health agencies notified. This modified 3I tool will assist emergency and primary care clinicians, as well as out-of-hospital providers, in effectively managing persons with suspected or confirmed 2019-nCoV
Evaluation of Continuous Monitoring as a Tool for Municipal Stormwater Management Programs
The purpose of this study is to evaluate the uncertainty attributable to inadequate temporal sampling of stormwater discharge and water quality, and understand its implications for meeting monitoring objectives relevant to municipal separate storm sewer systems (MS4s). A methodology is presented to evaluate uncertainty attributable to inadequate temporal sampling of continuous stormflow and water quality, and a case study demonstrates the application of the methodology to six small urban watersheds (0.8-6.8 km2) and six large rural watersheds (30-16,192 km2) in Virginia. Results indicate the necessity of high-frequency continuous monitoring for accurately capturing multiple monitoring objectives, including illicit discharges, acute toxicity events, and stormflow pollutant concentrations and loads, as compared to traditional methods of sampling. For example, 1-h sampling in small urban watersheds and daily sampling in large rural watersheds would introduce uncertainty in capturing pollutant loads of 3–46% and 10–28%, respectively. Overall, the outcomes from this study highlight how MS4s can leverage continuous monitoring to meet multiple objectives under current and future regulatory environments
Orbifold Reduction Of The Quark-Lepton Symmetric Model
We investigate the quark-lepton symmetric gauge group in five dimensions,
with the gauge symmetry broken by a combination of orbifold compactification of
the extra dimension and the Higgs mechanism. The gauge sector of the model is
investigated and contrasted with the four dimensional case. We obtain lower
bounds on the mass of the exotic gauge bosons, the inverse compactification
scale and the exotic leptons. Light neutrinos are obtained without requiring
any scale larger than a TeV. However an ultra-violet cut-off of order
GeV is required to suppress proton decay inducing non-renormalizable operators.Comment: References added to match PRD versio
Suppressing Proton Decay By Separating Quarks And Leptons
Arkani-Hamed and Schmaltz (AS) have shown that proton stability need not
originate from symmetries in a high energy theory. Instead the proton decay
rate is suppressed if quarks and leptons are spatially separated in a compact
extra dimension. This separation may be achieved by coupling five dimensional
fermions to a bulk scalar field with a non-trivial vacuum profile and requires
relationships between the associated quark and lepton Yukawa couplings. We
hypothesise that these relationships are the manifestation of an underlying
symmetry. We further show that the AS proposal may suggest that proton
stability \emph{is} the result of an underlying symmetry, though not
necessarily the traditional baryon number symmetry.Comment: 4 pages, references added to match published versio
Thurstonian Scaling of Compositional Questionnaire Data
To prevent response biases, personality questionnaires may use comparative response formats. These include forced choice, where respondents choose among a number of items, and quantitative comparisons, where respondents indicate the extent to which items are preferred to each other. The present article extends Thurstonian modeling of binary choice data (Brown & Maydeu-Olivares, 2011a) to “proportion-of-total” (compositional) formats. Following Aitchison (1982), compositional item data are transformed into log-ratios, conceptualized as differences of latent item utilities. The mean and covariance structure of the log-ratios is modelled using Confirmatory Factor Analysis (CFA), where the item utilities are first-order factors, and personal attributes measured by a questionnaire are second-order factors. A simulation study with two sample sizes, N=300 and N=1000, shows that the method provides very good recovery of true parameters and near-nominal rejection rates. The approach is illustrated with empirical data from N=317 students, comparing model parameters obtained with compositional and Likert scale versions of a Big Five measure. The results show that the proposed model successfully captures the latent structures and person scores on the measured traits
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