Development of trip generation models of hurricane evacuation

In this study, alternative trip generation models for hurricane evacuation movement were developed using logistic regression and neural networks. The southwest Louisiana post-Andrew survey data were used for model estimation, validation, and comparison. The performance of the alternative models was compared with each other as well as against that of an existing evacuation model, the PBS&J model, developed for the same area. The results showed that the models developed in this study displayed similar performance. It was also found that the models developed in this study performed better than the existing PBS&J model in predicting household evacuation trip generation for southwestern Louisiana. The independent variables found to be significant in explaining household evacuation behavior included housing type, whether the household gets a mandatory evacuation order or not, age of the respondent, distance of the household from the closest body of water, and marital status of the respondent. Comparison of two model specifications involving different numbers of independent variables showed that the more comprehensive specification added very little to the explanatory power of the models and should be abandoned for model parsimony and ease of use

Lipopolysaccharide Animal Models for Parkinson\u27s Disease

Lipopolysaccharide (LPS), an endotoxin from Gram-negative bacteria, acts as a potent stimulator of microglia and has been used to study the inflammatory process in the pathogenesis of Parkinson\u27s disease (PD) and anti-inflammatory therapy for PD treatment. Here, we review the growing body of literature on both in vitro and in vivo LPS PD models. Primary cell cultures from mesencephalic tissue were exposed to LPS in vitro; LPS was stereotaxically injected into the substantia nigra, striatum, or globus pallidus of brain or injected into the peritoneal cavity of the animal in vivo. In conclusion, the LPS PD models are summarized as (1) local and direct LPS treatment and (2) systemic LPS treatment. Mechanisms underlying the PD models are investigated and indicated that LPS induces microglial activation to release a variety of neurotoxic factors, and damaged neurons may trigger reactive microgliosis, which lead to progressive dopaminergic neurodegeneration

Highly Charged Ion (HCI) Clocks: Frontier candidates for testing variation of fine-structure constant

Attempts are made to unify gravity with the other three fundamental forces of nature. As suggested by higher dimensional models, this unification may require space and time variation of some dimensionless fundamental constants. In this scenario, probing temporal variation of the electromagnetic fine structure constant ($\alpha= \frac{e^2} {\hbar c}$) in low energy regimes at the cosmological time scale is of immense interest. Atomic clocks are ideal candidates for probing $\alpha$ variation because their transition frequencies are measured to ultra-high precision accuracy. Since atomic transition frequencies are functions of $\alpha$, measurements of clock frequencies at different temporal and spatial locations can yield signatures to ascertain such conjecture. Electrons in highly charged ions (HCIs) experience unusually enhanced relativistic effects. Hence level-crossings can be observed often in these ions compared to their isoelectronic neutral or singly charged atomic systems. Such a process features by their more significant relativistic sensitive coefficients ($q$) of atomic transitions. For unambiguous detection of subtle changes in the transition frequencies due to $\alpha$ variation, it would be judicious to contemplate transitions for which $q$ values are enormous. HCIs are considered one of the most suitable candidates for making atomic clocks as they are the least sensitive to external electromagnetic fields owing to their exceptionally contracted orbitals. The first HCI clock has been realized, but its accuracy is much less than the counter optical clocks based on neutral atoms and singly charged ions. The realization of HCI clocks can add an extra dimension to investigating fundamental physics. In this work, we survey HCIs suitable for clock candidates on the grounds of general features, including their potential to probe temporal variation of $\alpha$.Comment: 35 pages, 12 table

Chiral selection and frequency response of spiral waves in reaction-diffusion systems under a chiral electric field

Chirality is one of the most fundamental properties of many physical, chemical and biological systems. However, the mechanisms underlying the onset and control of chiral symmetry are largely understudied. We investigate possibility of chirality control in a chemical excitable system (the BZ reaction) by application of a chiral (rotating) electric field using the Oregonator model. We find that unlike previous findings, we can achieve the chirality control not only in the field rotation direction, but also opposite to it, depending on the field rotation frequency. To unravel the mechanism, we further develop a comprehensive theory of frequency synchronization based on the response function approach. We find that this problem can be described by the Adler equation and show phase-locking phenomena, known as the Arnold tongue. Our theoretical predictions are in good quantitative agreement with the numerical simulations and provide a solid basis for chirality control in excitable media.Comment: 21 pages with 9 figures; update references; to appear in J. Chem. Phy

Poly[(μ4-5-bromo­pyridine-3-sulfonato)­silver(I)]

The silver(I) complex, [Ag(C5H3BrNO3S)]n, was obtained by reaction of AgNO3 and 5-bromopyridine-3-sulfonic acid. The AgI ion is coordinated by an O3N donor set in a slightly distorted tetra­hedral geometry. The AgI ions are linked by μ4-5-bromo­pyridine-3-sulfonate ligands, forming a layer parallel to (100). The layers are further connected via C—H⋯Br hydrogen-bonding inter­actions into a three-dimensional supra­molecular network. The Ag⋯Ag separation is 3.0159 (6) Å, indicating the presence of argentophilic inter­actions