2,533 research outputs found
EP-2072: Spatiotemporal dynamics of DNA damage in cells exposed to mixed beams of ionising radiation
Magnetospheric Multiscale Observations of Markov Turbulence on Kinetic Scales
In our previous studies we have examined solar wind and magnetospheric
plasmas turbulence, including Markovian character on large inertial
magneto-hydrodynamic scales. Here we present the results of statistical
analysis of magnetic field fluctuations in the Earth's magnetosheath based on
Magnetospheric Multiscale mission at much smaller kinetic scales. Following our
results on spectral analysis with very large slopes of about -16/3, we apply
Markov processes approach to turbulence in this kinetic regime. It is shown
that the Chapman-Kolmogorov equation is satisfied and the lowest-order
Kramers-Moyal coefficients describing drift and diffusion with a power-law
dependence are consistent with a generalized Ornstein-Uhlenbeck process. The
solutions of the Fokker-Planck equation agree with experimental probability
density functions, which exhibit a universal global scale invariance through
the kinetic domain. In particular, for moderate scales we have the kappa
distribution described by various peaked shapes with heavy tails, which with
large values of kappa parameter are reduced to the Gaussian distribution for
large inertial scales. This shows that the turbulence cascade can be described
by the Markov processes also on very small scales. The obtained results on
kinetic scales may be useful for better understanding of the physical
mechanisms governing turbulenceComment: accepted to Astrophys. J. 2 November 2022, 17 pages, 7 figure
Ghosts- and Tachyon-Free Regions of the Randall-Sundrum Model Parameter Space
Model building within the Randall-Sundrum (RS) framework generally involves
placing the Standard Model fields in the bulk. Such fields may possess non-zero
values for their associated brane-localized kinetic terms (BLKTs) in addition
to possible bulk mass parameters. In this paper we clearly identify the regions
of the RS model parameter space where the presence of bulk mass terms and BLKTs
yield a setup which is free from both ghost and tachyon instabilities. Such
physically acceptable parameter space regions can then be used to construct
realistic and phenomenologically viable RS models.Comment: Latex, 30 pages, 2 figure
Key Bifurcations of Bursting Polyrhythms in 3-Cell Central Pattern Generators
We identify and describe the key qualitative rhythmic states in various 3-cell network motifs of a multifunctional central pattern generator (CPG). Such CPGs are neural microcircuits of cells whose synergetic interactions produce multiple states with distinct phase-locked patterns of bursting activity. To study biologically plausible CPG models, we develop a suite of computational tools that reduce the problem of stability and existence of rhythmic patterns in networks to the bifurcation analysis of fixed points and invariant curves of a Poincare´ return maps for phase lags between cells. We explore different functional possibilities for motifs involving symmetry breaking and heterogeneity. This is achieved by varying coupling properties of the synapses between the cells and studying the qualitative changes in the structure of the corresponding return maps. Our findings provide a systematic basis for understanding plausible biophysical mechanisms for the regulation of rhythmic patterns generated by various CPGs in the context of motor control such as gait-switching in locomotion. Our analysis does not require knowledge of the equations modeling the system and provides a powerful qualitative approach to studying detailed models of rhythmic behavior. Thus, our approach is applicable to a wide range of biological phenomena beyond motor control
Collective Antenna Effects in the Terahertz and Infrared Response of Highly Aligned Carbon Nanotube Arrays
We study macroscopically-aligned single-wall carbon nanotube arrays with
uniform lengths via polarization-dependent terahertz and infrared transmission
spectroscopy. Polarization anisotropy is extreme at frequencies less than
3 THz with no sign of attenuation when the polarization is perpendicular
to the alignment direction. The attenuation for both parallel and perpendicular
polarizations increases with increasing frequency, exhibiting a pronounced and
broad peak around 10 THz in the parallel case. We model the electromagnetic
response of the sample by taking into account both radiative scattering and
absorption losses. We show that our sample acts as an effective antenna due to
the high degree of alignment, exhibiting much larger radiative scattering than
absorption in the mid/far-infrared range. Our calculated attenuation spectrum
clearly shows a non-Drude peak at 10 THz in agreement with the
experiment.Comment: 5 pages, 5 figure
AIDS: Testing Democracy - Irrational Responses to the Public Health Crisis and the Need for Privacy in Serologic Testing, 19 J. Marshall L. Rev. 835 (1986)
Synthesis of homo- and heteromultivalent carbohydrate-functionalized oligo(amidoamines) using novel glyco-building blocks
We present the solid phase synthesis of carbohydrate-functionalized oligo(amidoamines) with different functionalization patterns utilizing a novel alphabet of six differently glycosylated building blocks. Highly efficient in flow conjugation of thioglycosides to a double-bond presenting diethylentriamine precursor is the key step to prepare these building blocks suitable for fully automated solid-phase synthesis. Introduction of the sugar ligands via functionalized building blocks rather than postfunctionalization of the oligomeric backbone allows for the straightforward synthesis of multivalent glycoligands with full control over monomer sequence and functionalization pattern. We demonstrate the potential of this building-block approach by synthesizing oligomers with different numbers and spacing of carbohydrates and also show the feasibility of heteromultivalent glycosylation patterns by combining building blocks presenting different mono- and disaccharides
Performance of emergency physicians utilizing a video-assisted semi-rigid fiberoptic stylet for intubation of a difficult airway in a high-fidelity simulated patient: a pilot study
BACKGROUND: This study was designed to evaluate emergency physician success and satisfaction using a video-assisted semi-rigid fiberoptic stylet, the Clarus Video System (CVS), during a simulated difficult airway scenario. FINDINGS: Emergency physicians (EPs) of all levels were first shown a brief slide show and three example videos, and then given 20 min to practice intubating a mannequin using both the CVS and standard direct laryngoscopy (DL). The mannequin was then placed in a c-collar and set to simulate an apneic patient with an edematous tongue and trismus. Each EP was given up to three timed attempts with each technique. They rated their satisfaction with the CVS, usefulness for their practice, and the effectiveness of the tutorial. Direct laryngoscopy had a 65% success rate on the first attempt, 20% on the second, and 15% required three or more. The CVS had a 100% success rate with a single attempt. Average time for independent DL attempts was 43.41 s (SD = ±26.82) and 38.71 s (SD = ±34.14) with CVS. Cumulative attempt times were analyzed and compared (DL = 74.55 ± 68.40 s and CVS = 38.71 ± 34.14 s; p = 0.028). EPs rated their satisfaction with, and usefulness of, the CVS as ≥6 out of 10. CONCLUSION: Emergency physicians were able to successfully intubate a simulated difficult airway model on the first attempt 100% of the time. Emergency physicians were satisfied with the CVS and felt that it would be useful in their practice
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