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  • 1
    Language: English
    In: The journal of high energy physics, 2020-02, Vol.2020 (2), p.1-31
    Description: In extended supersymmetric models with a hidden sector the lightest R-parity odd particle can reside in the hidden sector and act as dark matter. We consider the case when the hidden sector has ultraweak interactions with the visible sector. An interesting phenomenon arises if the LSP of the visible sector is charged in which case it will decay to the hidden sector dark matter. Due to the ultraweak interactions, the LSP of the visible sector will be long-lived decaying outside the detector after leaving a track inside. We investigate this possibility in the framework of a U(1)X-extended MSSM/SUGRA model with a small gauge kinetic mixing and mass mixing between the U(1)X and U(1)Y where U(1)Y is the gauge group of the hypercharge. Specifically we investigate the case when the LSP of MSSM is a stop which decays into the hidden sector dark matter and has a lifetime long enough to traverse the LHC detector without decay. It is shown that such a particle can be detected at the HL-LHC and HE-LHC as an R-hadron which will look like a slow moving muon with a large transverse momentum pT and so can be detected by the track it leaves in the inner tracker and in the muon spectrometer. Further, due to the ultraweak couplings between the hidden sector and the MSSM fields, the dark matter particle has a relic density arising from a combination of the freeze-out and freeze-in mechanisms. It is found that even for the ultraweak or feeble interactions the freeze-out contribution relative to freeze-in contribution to the relic density is substantial to dominant, varying between 30% to 74% for the model points considered. It is subdominant to freeze-in for relatively small stop masses with relatively larger stop annihilation cross-sections and the dominant contribution to the relic density for relatively large stop masses and relatively smaller stop annihilation cross-sections. Our analysis shows that the freeze-out contribution must be included for any realistic analysis even for dark matter particles with ultraweak or feeble interactions with the visible sector. A discovery of a long-lived stop as the lightest particle of the MSSM may point to the nature of dark matter and its production mechanism in the early universe.
    Subject(s): Couplings ; Standard model (particle physics) ; Dark matter ; Large Hadron Collider ; Particle decay ; Transverse momentum ; Density ; Cross sections ; Muons ; Supersymmetric Standard Model ; Beyond Standard Model
    ISSN: 1029-8479
    E-ISSN: 1029-8479
    Source: SCOAP3 Journals
    Source: Directory of Open Access Journals
    Source: ProQuest Central
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 2
    Language: English
    In: The journal of high energy physics, 2020-04, Vol.2020 (4), p.1-32
    Description: SUSY/SUGRA models with naturalness defined via small μ are constrained due to experiment on the relic density and the experimental limits on the WIMP-proton cross-section and WIMP annihilation cross-section from indirect detection experiments. Specifically models with small μ where the neutralino is higgsino-like lead to dark matter relic density below the observed value. In several works this problem is overcome by assuming dark matter to be constituted of more than one component and the neutralino relic density deficit is made up from contributions from other components. In this work we propose that the dark matter consists of just one component, i.e., the lightest neutralino and the relic density of the higgsino-like neutralino receives contributions from the usual freeze-out mechanism along with contributions arising from the decay of hidden sector neutralinos. The model we propose is an extended MSSM model where the hidden sector is constituted of a U(1)X gauge sector along with matter charged under U(1)X which produce two neutralinos in the hidden sector. The U(1)X and the hypercharge U(1)Y of the MSSM have kinetic and Stueckelberg mass mixing where the mixings are ultraweak. In this case the hidden sector neutralinos have ultraweak interactions with the visible sector. Because of their ultraweak interactions the hidden sector neutralinos are not thermally produced and we assume their initial relic density to be negligible. However, they can be produced via interactions of MSSM particles in the early universe, and once produced they decay to the neutralino. For a range of mixings the decays occur before the BBN producing additional relic density for the neutralino. Models of this type are testable in dark matter direct and indirect detection experiments and at the high luminosity and high energy LHC.
    Subject(s): Standard model (particle physics) ; Supersymmetry ; Weakly interacting massive particles ; Dark matter ; Large Hadron Collider ; Fermions ; Particle decay ; Luminosity ; Higgs bosons ; Density ; Cross sections ; Supersymmetry Phenomenology
    ISSN: 1029-8479
    E-ISSN: 1029-8479
    Source: SCOAP3 Journals
    Source: Directory of Open Access Journals
    Source: ProQuest Central
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 3
    Language: English
    In: Cancer research (Chicago, Ill.), 2018-08-01, Vol.78 (15), p.4150-4162
    Description: Twist is a critical epithelial-mesenchymal transition (EMT)-inducing transcription factor that increases expression of vimentin. How Twist1 regulates this expression remains unclear. Here, we report that Twist1 regulates Cullin2 (Cul2) circular RNA to increase expression of vimentin in EMT. Twist1 bound the Cul2 promoter to activate its transcription and to selectively promote expression of Cul2 circular RNA (circ-10720), but not mRNA. circ-10720 positively correlated with Twist1, tumor malignance, and poor prognosis in hepatocellular carcinoma (HCC). Twist1 promoted vimentin expression by increasing levels of circ-10720, which can absorb miRNAs that target vimentin. circ-10720 knockdown counteracted the tumor-promoting activity of Twist1 and in patient-derived xenograft and diethylnitrosamine-induced TetOn-Twist1 transgenic mouse HCC models. These data unveil a mechanism by which Twist1 regulates vimentin during EMT. They also provide potential therapeutic targets for HCC treatment and provide new insight for circular RNA (circRNA)-based diagnostic and therapeutic strategies. A circRNA-based mechanism drives Twist1-mediated regulation of vimentin during EMT and provides potential therapeutic targets for treatment of HCC. http://cancerres.aacrjournals.org/content/canres/78/15/4150/F1.large.jpg .
    Subject(s): Cell Line ; Liver Neoplasms - genetics ; Humans ; Signal Transduction - genetics ; Epithelial-Mesenchymal Transition - genetics ; Promoter Regions, Genetic - genetics ; RNA - genetics ; Cullin Proteins - genetics ; Animals ; Vimentin - genetics ; Carcinoma, Hepatocellular - genetics ; HEK293 Cells ; Twist-Related Protein 1 - genetics ; Cell Line, Tumor ; Mice ; Nuclear Proteins - genetics ; Gene Expression Regulation, Neoplastic - genetics
    ISSN: 0008-5472
    E-ISSN: 1538-7445
    Source: HighWire Press (Free Journals)
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 4
    Language: English
    In: Boundary-layer meteorology, 2011-03, Vol.138 (3), p.367-384
    Description: Large-eddy simulation (LES) is used to simulate stably-stratified turbulent boundary-layer flow over a steep two-dimensional hill. To parametrise the subgrid-scale (SGS) fluxes of heat and momentum, three different types of SGS models are tested: (a) the Smagorinsky model, (b) the Lagrangian dynamic model, and (c) the scale-dependent Lagrangian dynamic model (Stoll and Porté-Agel, Water Resour Res 2006, doi: 10.1029/2005WR003989 ). Simulation results obtained with the different models are compared with data from wind-tunnel experiments conducted at the Environmental Flow Research Laboratory (EnFlo), University of Surrey, U.K. (Ross et al., Boundary-Layer Meteorol 113:427–459, 2004). It is found that, in this stably-stratified boundary-layer flow simulation, the scale-dependent Lagrangian dynamic model is able to account for the scale dependence of the eddy-viscosity and eddy-diffusivity model coefficients associated with flow anisotropy in flow regions with large mean shear and/or strong flow stratification. As a result, simulations using this tuning-free model lead to turbulence statistics that are more realistic than those obtained with the other two models.
    Subject(s): Earth Sciences ; Meteorology/Climatology ; Large-eddy simulation ; Stable stratification ; Subgrid-scale modelling ; Atmospheric Protection/Air Quality Control/Air Pollution ; Two-dimensional hill ; Earth, ocean, space ; External geophysics ; Convection, turbulence, diffusion. Boundary layer structure and dynamics ; Exact sciences and technology ; Meteorology ; Turbulence ; Models ; Anisotropy ; Analysis
    ISSN: 0006-8314
    E-ISSN: 1573-1472
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 5
    Language: English
    In: IEEE transactions on signal processing, 2008-07, Vol.56 (7), p.2821-2834
    Description: In this paper, a very efficient semiblind approach that uses a training-based least square criterion along with a blind constraint is proposed for multiple-input-multiple-output-orthogonal frequency-division multiplexing (MIMO-OFDM) channel estimation. The blind constraint is derived from the linear prediction of the received MIMO-OFDM signal and is used in conjunction with a weighting factor in the semiblind cost function. An appealing scheme for the determination of the weighting factor is presented as a part of the proposed approach. A perturbation analysis of the proposed method is conducted to justify the superiority of the semiblind solution and to obtain a closed-form expression for the mean square error (MSE) of the blind constraint, further facilitating the calculation of the weighting factor. The proposed method is validated through computer simulation-based experimentations, showing a very high estimation accuracy of the semiblind solution in terms of the MSE of the channel estimate.
    Subject(s): OFDM ; perturbation analysis ; MIMO-orthogonal frequency-division multiplexing (MIMO-OFDM) ; semiblind ; Frequency estimation ; Vectors ; Frequency division multiplexing ; Statistics ; Least squares approximation ; Channel estimation ; Receiving antennas ; Signal processing algorithms ; Mean square error methods ; multiple-input-multiple-output (MIMO) linear prediction ; Signal and communications theory ; Multiplexing ; Miscellaneous ; Telecommunications and information theory ; Exact sciences and technology ; Signal, noise ; Signal processing ; Applied sciences ; Information, signal and communications theory ; Detection, estimation, filtering, equalization, prediction ; Evaluation ; Analysis ; Perturbation (Mathematics) ; Bandwidth ; Research ; MIMO communications
    ISSN: 1053-587X
    E-ISSN: 1941-0476
    Source: IEEE Electronic Library (IEL)
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  • 6
    Language: English
    In: OncoTargets and therapy, 2016, Vol.9, p.7451-7458
    Description: Nowadays, despite great progress in cancer research, the detailed mechanisms of colorectal cancer (CRC) are still poorly understood. Circular RNAs (circRNAs), a new star of the non-coding RNA network, have been identified as critical regulators in various cancers, including CRC. In this study, by using unsupervised hierarchical clustering analysis, a novel dysregulated circRNA, hsa_circ_0000069, was found. The expression of hsa_circ_0000069 was measured in 30 paired CRC tissues and adjacent noncancerous tissues using quantitative polymerase chain reaction. A high expression of hsa_circ_0000069 was observed in CRC tissues and correlated with patients' age and tumor, node, metastasis (TNM) stage ( 〈0.05). Furthermore, by using specifically designed siRNAs in CRC cells, a functional analysis was performed which revealed that hsa_circ_0000069 knockdown could notably inhibit cell proliferation, migration, and invasion, and induce G0/G1 phase arrest of cell cycle in vitro. This study's findings are the first to demonstrate that hsa_circ_0000069, an important regulator in cancer progression, could be a promising target in the diagnosis and therapy in colorectal cancer.
    Subject(s): Cell proliferation ; Prognosis ; MicroRNA ; Analysis ; Colorectal cancer ; Development and progression ; Diagnosis ; Research ; Biological markers ; Care and treatment ; Genetic aspects ; Gene expression ; Health aspects ; Oncogenes ; Data analysis ; Dehydrogenases ; Clustering ; Stomach cancer ; Cell adhesion & migration ; Polymerase chain reaction ; Liver cancer ; Cell growth ; Hospitals ; MicroRNAs ; Cell cycle ; Biomarkers ; Alzheimers disease ; Apoptosis ; hsa_circ_0000069 ; colorectal cancer ; regulation ; Original Research ; circular RNA
    ISSN: 1178-6930
    E-ISSN: 1178-6930
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: Directory of Open Access Journals
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 7
    Language: English
    In: Microbial cell factories, 2018-01-29, Vol.17 (1), p.15-15
    Description: The CRISPR/dCas9 system is a powerful tool to activate the transcription of target genes in eukaryotic or prokaryotic cells, but lacks assays in complex conditions, such as the biosynthesis of secondary metabolites. In this study, to improve the transcription of the heterologously expressed biosynthetic genes for the production of epothilones, we established the CRISPR/dCas9-mediated activation technique in Myxococcus xanthus and analyzed some key factors involving in the CRISPR/dCas9 activation. We firstly optimized the cas9 codon to fit the M. xanthus cells, mutated the gene to inactivate the nuclease activity, and constructed the dCas9-activator system in an epothilone producer. We compared the improvement efficiency of different sgRNAs on the production of epothilones and the expression of the biosynthetic genes. We also compared the improvement effects of different activator proteins, the ω and α subunits of RNA polymerase, and the sigma factors σ54 and CarQ. By using a copper-inducible promoter, we determined that higher expressions of dCas9-activator improved the activation effects. Our results showed that the CRISPR/dCas-mediated transcription activation is a simple and broadly applicable technique to improve the transcriptional efficiency for the production of secondary metabolites in microorganisms. This is the first time to construct the CRISPR/dCas9 activation system in myxobacteria and the first time to assay the CRISPR/dCas9 activations for the biosynthesis of microbial secondary metabolites.
    Subject(s): Promoter Regions, Genetic ; Multigene Family ; Epothilones - biosynthesis ; RNA, Guide - genetics ; Transcriptional Activation ; Myxococcus xanthus - genetics ; Recombinant Proteins - genetics ; Myxococcus xanthus - metabolism ; CRISPR-Cas Systems - genetics ; CRISPR-Associated Protein 9 - genetics ; Secondary Metabolism ; CRISPR-Associated Protein 9 - metabolism ; Epothilones - genetics ; Transcription, Genetic ; Usage ; Microbiological synthesis ; Physiological aspects ; Genetic aspects ; Research ; Myxobacterales ; Genetic transcription ; Plant metabolites ; Production processes ; Index Medicus ; Promoter ; CRISPR ; dCas9 activation ; Myxococcus xanthus ; Activator proteins ; Biosynthetic gene cluster ; sgRNAs ; Transcriptional improvement ; Epothilones ; CRISPR/dCas9 activation
    ISSN: 1475-2859
    E-ISSN: 1475-2859
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: Directory of Open Access Journals
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 8
    Article
    Article
    2016
    ISSN: 1029-8479 
    Language: English
    In: The journal of high energy physics, 2016-04, Vol.2016 (4), p.1-15
    Description: To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1007/JHEP04(2016)090 We discuss the diboson excess seen by the ATLAS collaboration around 2 TeV in the LHC run I at 〈![CDATA[ ]]〉 s = 8 〈![CDATA[ ]]〉 =8 TeV. We explore the possibility that such an excess can arise from a Z boson which acquires mass through a U(1).sub.X Stueckelberg extension. The corresponding Z gauge boson is leptophobic with a mass of around 2 TeV and has interactions with SU(2).sub.L Yang-Mills fields and gauge fields of the hypercharge. The analysis predicts Z decays into WW and ZZ as well as into ZI[sup.3]. Further three-body as well as four-body decays of the Z such as WWZ, WWI[sup.3], WWZZ etc are predicted. In the analysis we use the helicity formalism which allows us to exhibit the helicity structure of the Z decay processes in an transparent manner. In particular, we are able to show the set of vanishing helicity amplitudes in the decay of the massive Z into two vector bosons due to angular momentum conservation with a special choice of the reference momenta. The residual set of non-vanishing helicity amplitudes are identified. The parameter space of the model compatible with the diboson excess seen by the ATLAS experiment at 〈![CDATA[ ]]〉 s = 8 〈![CDATA[ ]]〉 =8 TeV is exhibited. Estimate of the diboson excess expected at 〈![CDATA[ ]]〉 s = 13 〈![CDATA[ ]]〉 =13 TeV with 20 fb.sup.-1 of integrated luminosity at LHC run II is also given. It is shown that the WW, ZZ and ZI[sup.3] modes are predicted to be in the approximate ratio 1 : cos.sup.2 I[cedilla] .sub.W (1 + [alpha] tan.sup.2 I[cedilla] .sub.W).sup.2 /2 : (1 - [alpha]).sup.2 sin.sup.2 I[cedilla].sub.W /2 where [alpha] is the strength of the coupling of Z with the hypercharge gauge field relative to the coupling with the Yang-Mills gauge fields. Thus observation of the ZI[sup.3] mode as well as three-body and four-body decay modes of the Z will provide a definite test of the model and of a possible new source of interaction beyond the standard model.
    Subject(s): Phenomenology ; High Energy Physics - Phenomenology ; High Energy Physics ; Gauge Symmetry ; Beyond Standard Model ; Nuclear and High Energy Physics ; Experiment ; High Energy Physics - Experiment
    ISSN: 1029-8479
    E-ISSN: 1029-8479
    Source: SCOAP3 Journals
    Source: Directory of Open Access Journals
    Source: ProQuest Central
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  • 9
    Language: English
    In: Environment international, 2018-12, Vol.121 (Pt 2), p.1155-1161
    Description: The transmission routes for antibiotic resistance genes (ARGs) and microbiota between humans and water environments is poorly characterized. Here, we used high-throughput qPCR analyses and 16S rRNA gene sequencing to examine the occurrence and abundance of antibiotic resistance genes and microbiota in both healthy humans and associated water environments from a Chinese village. Humans carried the most diverse assemblage of ARGs, with 234 different ARGs being detected. The total abundance of ARGs in feces, on skin, and in the effluent from domestic sewage treatment systems were approximately 23, 2, and 7 times higher than their abundance in river samples. In total, 53 ARGs and 28 bacteria genera that were present in human feces could also be found in the influent and effluent of rural sewage treatment systems, and also downstream of the effluent release point. We identified the bacterial taxa that showed a significant association with ARGs (P 〈 0.01, r 〉 0.8) by network analysis, supporting the idea that these bacteria could carry some ARGs and transfer between humans and the environment. Analysis of ARGs and microbiota in humans and in water environments helps to define the transmission routes and dynamics of antibiotic resistance within these environments. This study highlights human contribution to the load of ARGs into the environment and suggests means to prevent such dissemination. [Display omitted] •A total of 53 ARG subtypes were persistent in humans and water environments.•ARGs were enriched in humans and could be disseminated into water environments.•Co-occurrence of persistent ARGs and bacteria was defined by network analysis.
    Subject(s): Human ; Resistance ; Drinking water ; Wastewater ; Aquatic ; Peri-urban ; Yuan (China) ; Drug resistance in microorganisms ; Sewage ; Purification ; Microbiota (Symbiotic organisms) ; RNA ; Analysis ; Green technology ; Bacteria ; Index Medicus
    ISSN: 0160-4120
    E-ISSN: 1873-6750
    Source: Directory of Open Access Journals
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 10
    Language: English
    In: Boundary-layer meteorology, 2011-11, Vol.141 (2), p.201-217
    Description: Most natural landscapes are characterized by multiscale (often multifractal) topography with well-known scale-invariance properties. For example, the spectral density of landscape elevation fields is often found to have a power-law scaling behaviour (with a −2 slope on a log–log scale) over a wide span of spatial scales, typically ranging from tens of kilometres down to a few metres. Even though the effect of topography on the atmospheric boundary layer (ABL) has been the subject of numerous studies, few have focussed on multiscale topography. In this study, large-eddy simulation (LES) is used to investigate boundary-layer flow over multiscale topography, and guide the development of parametrizations needed to represent the effects of subgrid-scale (SGS) topography in numerical models of ABL flow. Particular emphasis is placed on the formulation of an effective roughness used to account for the increased aerodynamic roughness associated with SGS topography. The LES code uses the scale-dependent Lagrangian dynamic SGS model for the turbulent stresses and a terrain-following coordinate transformation to explicitly resolve the effects of the topography at scales larger than the LES resolution. The terrain used in the simulations is generated using a restricted solid-on-solid landscape evolution model, and it is characterized by a −2 slope of the elevation power spectrum. Results from simulations performed using elevation fields band-pass filtered at different spatial resolutions indicate a clear linear relation between the square of the effective roughness and the variance of elevation.
    Subject(s): Earth Sciences ; Meteorology/Climatology ; Multiscale complex terrain ; Subgrid-scale topography ; Atmospheric Protection/Air Quality Control/Air Pollution ; Large-eddy simulation ; Earth, ocean, space ; External geophysics ; Convection, turbulence, diffusion. Boundary layer structure and dynamics ; Exact sciences and technology ; Meteorology ; Laws, regulations and rules ; Landscape evolution ; Analysis ; Planetary boundary layer
    ISSN: 0006-8314
    E-ISSN: 1573-1472
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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