63,353 research outputs found
Diffusion in a continuum model of self-propelled particles with alignment interaction
In this paper, we provide the corrections to the hydrodynamic
model derived by Degond and Motsch from a kinetic version of the model by
Vicsek & coauthors describing flocking biological agents. The parameter
stands for the ratio of the microscopic to the macroscopic scales.
The corrected model involves diffusion terms in both the mass and
velocity equations as well as terms which are quadratic functions of the first
order derivatives of the density and velocity. The derivation method is based
on the standard Chapman-Enskog theory, but is significantly more complex than
usual due to both the non-isotropy of the fluid and the lack of momentum
conservation
Estimates of isospin breaking contributions to baryon masses
We estimate the isospin breaking contributions to the baryon masses which we
analyzed recently using a loop expansion in the heavy baryon approximation to
chiral effective field theory. To one loop, the isospin breaking corrections
come from the effects of the quark mass difference, the Coulomb and
magnetic moment interactions, and effective point interactions attributable to
color-magnetic effects. The addition of the first meson loop corrections
introduces new structure. We estimate the resulting low-energy, long-range
contributions to the mass splittings by regularizing the loop integrals using
connections to dynamical models for finite-size baryons. We find that the
resulting contributions to the isospin breaking corrections are of the right
general size, have the correct sign pattern, and agree with the experimental
values within the margin of error.Comment: 15 pages, 5 figures; changed title and conten
One parameter family of indecomposable optimal entanglement witnesses arising from generalized Choi maps
In the recent paper [Chru\'{s}ci\'{n}ski and Wudarski, arXiv:1105.4821], it
was conjectured that the entanglement witnesses arising from some generalized
Choi maps are optimal. We show that this conjecture is true. Furthermore, we
show that they provide a one parameter family of indecomposable optimal
entanglement witnesses.Comment: 3 page
Bloch-mode analysis for retrieving effective parameters of metamaterials
We introduce a new approach for retrieving effective parameters of
metamaterials based on the Bloch-mode analysis of quasi-periodic composite
structures. We demonstrate that, in the case of single-mode propagation, a
complex effective refractive index can be assigned to the structure, being
restored by our method with a high accuracy. We employ both surface and volume
averaging of the electromagnetic fields of the dominating (fundamental) Bloch
modes to determine the Bloch and wave impedances, respectively. We discuss how
this method works for several characteristic examples, and demonstrate that
this approach can be useful for retrieval of both material and wave effective
parameters of a broad range of metamaterials.Comment: 12 pages, 10 figure
Biochemical Properties of a Decoy Oligodeoxynucleotide Inhibitor of STAT3 Transcription Factor.
Cyclic STAT3 decoy (CS3D) is a second-generation, double-stranded oligodeoxynucleotide (ODN) that mimics a genomic response element for signal transducer and activator of transcription 3 (STAT3), an oncogenic transcription factor. CS3D competitively inhibits STAT3 binding to target gene promoters, resulting in decreased expression of proteins that promote cellular proliferation and survival. Previous studies have demonstrated antitumor activity of CS3D in preclinical models of solid tumors. However, prior to entering human clinical trials, the efficiency of generating the CS3D molecule and its stability in biological fluids should be determined. CS3D is synthesized as a single-stranded ODN and must have its free ends ligated to generate the final cyclic form. In this study, we report a ligation efficiency of nearly 95 percent. The ligated CS3D demonstrated a half-life of 7.9 h in human serum, indicating adequate stability for intravenous delivery. These results provide requisite biochemical characterization of CS3D that will inform upcoming clinical trials
Spin-Charge Separation at Finite Temperature in the Supersymmetric t-J Model with Long-Range Interactions
Thermodynamics is derived rigorously for the 1D supersymmetric {\it t-J}
model and its SU() generalization with inverse-square exchange. The system
at low temperature is described in terms of spinons, antispinons, holons and
antiholons obeying fractional statistics. They are all free and make the spin
susceptibility independent of electron density, and the charge susceptibility
independent of magnetization. Thermal spin excitations responsible for the
entropy of the SU() model are ascribed to free para-fermions of order
.Comment: 10 pages, REVTE
PENGETAHUAN KADER TENTANG PROSES MENUA DENGAN KEAKTIFAN KADER PADA PELAKSANAAN POSBINDU DI KELURAH SENDANGMULYO KECAMATAN TEMBALANG SEMARANG
Dari survai pendahuluan pada Posbindu di Kelurahan Sendangmulyo Kecamatan Tembalang Kota Semarang ada 17 Posbindu yang aktif dengan jumlah kader sebanyak 86 orang dan ada beberapa kader masuk kategori tidak aktif. Keaktifan kader diduga berkaitan dengan pengetahuannya tentang proses menua. Tujuan penelitian untuk mengetahui hubungan pengetahuan kader tentang proses menua dengan keaktifan kader pada pelaksanaan Posbindu di Kelurahan Sendangmulyo Kecamatan Tembalang Kota Semarang. Jenis penelitian ini adalah descriptive correlatif dengan pendekatan cross sectional. Teknik sampel menggunakan Total Sampling, sehingga 86 responden. Analisis datamenggunakan Korelasi Person Product Moment karena data berdistribusi normal. Hasil: rata-rata umur kader 41 tahun, perempuan (100%), SMA (62,8%), ibu rumah tangga (77,9%). Sebagian besar kader pengetahuan baik (98,8%), kader aktif (65,1%). Tidak ada hubungan antara pengetahuan kader dengan keaktifan kader di Kelurahan Sendangmulyo Kecamatan Tembalang Kota Semarang dengan p value 0,229 ( >0.05) .Kata Kunci : Pengetahuan, Keaktifan dan Kade
Singular Cucker-Smale Dynamics
The existing state of the art for singular models of flocking is overviewed,
starting from microscopic model of Cucker and Smale with singular communication
weight, through its mesoscopic mean-filed limit, up to the corresponding
macroscopic regime. For the microscopic Cucker-Smale (CS) model, the
collision-avoidance phenomenon is discussed, also in the presence of bonding
forces and the decentralized control. For the kinetic mean-field model, the
existence of global-in-time measure-valued solutions, with a special emphasis
on a weak atomic uniqueness of solutions is sketched. Ultimately, for the
macroscopic singular model, the summary of the existence results for the
Euler-type alignment system is provided, including existence of strong
solutions on one-dimensional torus, and the extension of this result to higher
dimensions upon restriction on the smallness of initial data. Additionally, the
pressureless Navier-Stokes-type system corresponding to particular choice of
alignment kernel is presented, and compared - analytically and numerically - to
the porous medium equation
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