A model of the DNA is proposed and studied analytically and numerically. The model is an extension of a well known model and describes the double helix as two chains of pendula (each pendulum representing a base). Each base (or pendulum) can rotate and translate along the helix axis. In the continuum limit the system is described by the perturbed Sine-Gordon equation describing the twist of the bases and by a nonlinear partial differential equation (PDE) describing the longitudinal displacements of the bases. This coupled system of PDEs was studied analytically using different approaches and the corresponding results were tested through numerical simulations. It was found that if the coupling parameters satisfy a well defined relationship, then there exist bounded travelling wave solutions.
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http://dx.doi.org/10.1016/j.mbs.2013.03.010 | DOI Listing |
Sci Rep
January 2025
Department of Psychiatry, New York State Psychiatric Institute, New York, NY, USA.
On October 7, 2023, a large-scale attack in southern Israel and the subsequent war resulted in extensive loss of life and injuries, with many individuals experiencing traumatic losses, such as family members or close friends being killed or kidnapped. This study aims to longitudinally examine its effects on mental health, specifically, clinical symptoms of anxiety, depression, and posttraumatic stress disorder (PTSD). We anticipated greater symptom severity among individuals who experienced traumatic loss, were forcibly displaced, or suffered income loss, as well as among women and members of ethnic minorities.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
We consider a half-filled Chern band and its transport properties in two phases that it may form: the electronic Fermi liquid and the composite-fermion Fermi liquid. For weak disorder, we show that the Hall resistivity for the former phase is very small, while for the latter it is close to 2h/e^{2}, independent of the distribution of the Berry curvature in the band. At rising temperature and high frequency, we expect the Hall resistivity of the electronic phase to rise, and that of the composite-fermion phase to deviate from 2h/e^{2}.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Information and Communications Technologies, Universidad Politécnica de Cartagena, Cartagena, Región de Murcia, Spain.
The Naval Ship Code (NSC) was enacted in 2009 to standardize regulations for NATO member naval forces, and a study commissioned by the Spanish Navy General Staff (EMA) aimed to identify the factors that influence onboard personnel's ability to move during an evacuation process. This study validated the soundness of the safety protocols implemented on navy vessels and highlighted the impact of certain characteristics of the embarked military contingent, such as body mass index, age, and seniority. It also found that such characteristics could act as distinctive factors among the embarked contingents in the evacuation of a military vessel.
View Article and Find Full Text PDFNat Commun
December 2024
Nanophotonics Research Center, Institute of Microscale Optoelectronics, State Key Laboratory of Radio Frequency Heterogeneous Integration, Shenzhen University, Shenzhen, 51806, China.
Optical metrology with picometer-scale precision in three-dimensional space is of considerable importance in modern physics and state of the art technology, optical interference is an effective method, but techniques with rapid spatial variation have the potential to enhance measurement precision, which will be required as measurement dimensions decrease. Here, the concept of the vanishingly small optical phase singularity ruler is introduced. Inspired by the well-known plumb-line technique used to locate the centroid, an analogous singularity line technique is proposed to locate the optical singularity with a precision of ~4.
View Article and Find Full Text PDFSci Rep
December 2024
Research Center of Space Structures, Guizhou University, Guiyang, 550025, China.
This study employed numerical simulation to investigate the dynamic response characteristics of open-web girders subjected to proximity blast loading and to compare these characteristics with those of solid-web girders. The research utilized the Coupled Eulerian-Lagrangian (CEL) method for simulation, effectively combining the advantages of both Eulerian and Lagrangian approaches. This method mitigated issues related to mesh distortion while accurately modeling the damage inflicted by blast loads on the structures.
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