Solid-liquid interfacial premelting

We report the observation of a premelting transition at chemically sharp solid-liquid interfaces using molecular-dynamics simulations. The transition is observed in the solid-Al/liquid-Pb system and involves the formation of a liquid interfacial film of Al with a width that grows logarithmically as the bulk melting temperature is approached from below, consistent with current theories of premelting. The premelting behavior leads to a sharp change in the temperature dependence of the diffusion coefficient in the interfacial region, and could have important consequences for phenomena such as particle coalescence and shape equilibration, which are governed by interfacial kinetic processes.Comment: 6 pages, 4 figure

Evaluation of Constant Potential Method in Simulating Electric Double-Layer Capacitors

A major challenge in the molecular simulation of electric double layer capacitors (EDLCs) is the choice of an appropriate model for the electrode. Typically, in such simulations the electrode surface is modeled using a uniform fixed charge on each of the electrode atoms, which ignores the electrode response to local charge fluctuations induced by charge fluctuations in the electrolyte. In this work, we evaluate and compare this Fixed Charge Method (FCM) with the more realistic Constant Potential Method (CPM), [Reed, et al., J. Chem. Phys., 126, 084704 (2007)], in which the electrode charges fluctuate in order to maintain constant electric potential in each electrode. For this comparison, we utilize a simplified LiClO$_4$-acetonitrile/graphite EDLC. At low potential difference ($\Delta\Psi\le 2V$), the two methods yield essentially identical results for ion and solvent density profiles; however, significant differences appear at higher $\Delta\Psi$. At $\Delta\Psi\ge 4V$, the CPM ion density profiles show significant enhancement (over FCM) of "partially electrode solvated" Li$^+$ ions very close to the electrode surface. The ability of the CPM electrode to respond to local charge fluctuations in the electrolyte is seen to significantly lower the energy (and barrier) for the approach of Li$^+$ ions to the electrode surface.Comment: Corrected typo

A Cobalt-Containing Eukaryotic Nitrile Hydratase

Nitrile hydratase (NHase), an industrially important enzyme that catalyzes the hydration of nitriles to their corresponding amides, has only been characterized from prokaryotic microbes. The putative NHase from the eukaryotic unicellular choanoflagellate organism Monosiga brevicollis (MbNHase) was heterologously expressed in Escherichia coli. The resulting enzyme expressed as a single polypeptide with fused α- and β-subunits linked by a seventeen-histidine region. Size-exclusion chromatography indicated that MbNHase exists primarily as an (αβ)2 homodimer in solution, analogous to the α2β2 homotetramer architecture observed for prokaryotic NHases. The NHase enzyme contained its full complement of Co(III) and was fully functional without the co-expression of an activator protein or E. coli GroES/EL molecular chaperones. The homology model of MbNHase was developed identifying Cys400, Cys403, and Cys405 as active site ligands. The results presented here provide the first experimental data for a mature and active eukaryotic NHase with fused subunits. Since this new member of the NHase family is expressed from a single gene without the requirement of an activator protein, it represents an alternative biocatalyst for industrial syntheses of important amide compounds

TV-GAN: Generative Adversarial Network Based Thermal to Visible Face Recognition

This work tackles the face recognition task on images captured using thermal camera sensors which can operate in the non-light environment. While it can greatly increase the scope and benefits of the current security surveillance systems, performing such a task using thermal images is a challenging problem compared to face recognition task in the Visible Light Domain (VLD). This is partly due to the much smaller amount number of thermal imagery data collected compared to the VLD data. Unfortunately, direct application of the existing very strong face recognition models trained using VLD data into the thermal imagery data will not produce a satisfactory performance. This is due to the existence of the domain gap between the thermal and VLD images. To this end, we propose a Thermal-to-Visible Generative Adversarial Network (TV-GAN) that is able to transform thermal face images into their corresponding VLD images whilst maintaining identity information which is sufficient enough for the existing VLD face recognition models to perform recognition. Some examples are presented in Figure 1. Unlike the previous methods, our proposed TV-GAN uses an explicit closed-set face recognition loss to regularize the discriminator network training. This information will then be conveyed into the generator network in the forms of gradient loss. In the experiment, we show that by using this additional explicit regularization for the discriminator network, the TV-GAN is able to preserve more identity information when translating a thermal image of a person which is not seen before by the TV-GAN

Consumer Behaviour in Lotto Markets: The Double Hurdle Approach and Zeros in Gambling Survey Data

Governments world-wide increasingly rely on gambling revenues, increasing the importance of understanding who gambles and why. Previous literature used Tobit and Heckman models to statistically analyze participation in gambling. These models make strong assumptions about the nature of gambling participation. We examine the double hurdle model as an alternative to other statistical approaches to modeling gambling participation and spending. Our results, based on data from a 2002 survey of gambling prevalence in Alberta, clearly prefer the double hurdle mode, which yields different results than the commonly used Tobit model.gambling; censored regression; double hurdle model

Special Points Arising From Faithful Metacyclic and Dicyclic Galois Covers of the Projective Line

Within the Schottky problem, the study of special subvarieties of the Torelli locus has long been of great interest. We present a criterion for a dimension $0$ subvariety of the Torelli locus, arising from a $G$-Galois cover of $\mathbb{P}^1$ branched at $3$ points, to be special. We develop methods to compute the complex multiplication field and type of Jacobian varieties arising from these covers, applying the representation theory of $G$ over $\mathbb{Q}$ and $\mathbb{Q}(\zeta_4)$. We also apply the Shimura-Taniyama formula to compute the Newton polygons of these Jacobians. We classify all the $G$-Galois covers for nonabelian faithful metacyclic groups $G$ and dicyclic groups $G$, identifying those that have complex multiplication.Comment: To be submitted to the Transactions of the American Mathematical Societ