Varicella-Zoster viruses associated with post-herpetic neuralgia induce sodium current density increases in the ND7-23 Nav-1.8 neuroblastoma cell line

Post-herpetic neuralgia (PHN) is the most significant complication of herpes zoster caused by reactivation of latent Varicella-Zoster virus (VZV). We undertook a heterologous infection in vitro study to determine whether PHN-associated VZV isolates induce changes in sodium ion channel currents known to be associated with neuropathic pain. Twenty VZV isolates were studied blind from 11 PHN and 9 non-PHN subjects. Viruses were propagated in the MeWo cell line from which cell-free virus was harvested and applied to the ND7/23-Nav1.8 rat DRG x mouse neuroblastoma hybrid cell line which showed constitutive expression of the exogenous Nav 1.8, and endogenous expression of Nav 1.6 and Nav 1.7 genes all encoding sodium ion channels the dysregulation of which is associated with a range of neuropathic pain syndromes. After 72 hrs all three classes of VZV gene transcripts were detected in the absence of infectious virus. Single cell sodium ion channel recording was performed after 72 hr by voltage-clamping. PHN-associated VZV significantly increased sodium current amplitude in the cell line when compared with non-PHN VZV, wild-type (Dumas) or vaccine VZV strains ((POka, Merck and GSK). These sodium current increases were unaffected by acyclovir pre-treatment but were abolished by exposure to Tetrodotoxin (TTX) which blocks the TTX-sensitive fast Nav 1.6 and Nav 1.7 channels but not the TTX-resistant slow Nav 1.8 channel. PHN-associated VZV sodium current increases were therefore mediated in part by the Nav 1.6 and Nav 1.7 sodium ion channels. An additional observation was a modest increase in message levels of both Nav1.6 and Nav1.7 mRNA but not Nav 1.8 in PHN virally infected cells

How Informative Is Floating NAV When Securities Trade Infrequently?

We examine if a floating net asset value (NAV) increases the transparency of risk for investors. Using closed-income fixed income funds we find little evidence that a floating NAV helps investors better understand the value and risk of a fund when a fund\u27s assets trade infrequently. This potentially informs the debate regarding the adoption of a floating NAV in the money market industry. Our results suggest that it is unlikely that the benefits of floating NAV will outweigh the costs

Effects of Regulatory and Market Constraints on the Capital Structure and Share Value of REITs: Evidence from the Italian Market

In contrast to the US experience, most international (European) real estate investments trusts (REITs) are subject to prudential regulation. This paper investigates the effects of prudential regulation on capital structures and consequently, the REIT share values of major legal and market constraints (i.e. leverage limitations, market discount on net asset value (NAV), tax controls) that affect non-US REITs. Italian market data are used for an empirical analysis. Our hypothesis is that in a constrained environment, the effects on share price significantly depend on the adopted valuation perspective, i.e. if shares are valued by following a NAV or a financial approach. The logic for this hypothesis is that the two valuation methodologies perceive leverage and implied financial risk differently. In particular, we argue that NAV valuation techniques incentivise REITs to maximize leverage regardless of the financial theory which indicates a contrasting impact of debt on the market value of shares. Differences in financial risk perception could also partially explain market price discounts on NAVs.The empirical results seem to support these expectations. Almost all Italian REITs tend to increase debt ratios over time. NAV discounts are significantly related to leverage. The discount effect is largely attributable to NAV increases that result from rising debt levels. On the contrary, share market prices tend to be independent from leverage. The latter result may indicate that the classic capital theory applies and current debt ratios do not imply bankruptcy risk. The results have significant policy implications in terms of an optimal regulatory design.REIT regulation; Leverage; NAV discount; REIT capital structure; REIT valuation

Do Stock Prices Really Reflect Fundamental Values? The Case of REITs

Real estate investment trust (REIT) stock prices deviate substantially from net asset values (NAV). Using REIT data since 1990, we find large positive excess returns to a strategy of buying stocks that trade at a discount to NAV, and shorting stocks trading at a premium to NAV. Estimated alphas from this strategy are between 0.9% and 1.8% per month, with little risk. Trading costs and short-sale constraints are not prohibitive and the results strengthen when we control for differences in liquidity or the extent of institutional ownership. We find that some variation in P/NAV makes sense, as premiums are positively related to recent and future NAV growth. However, there appears to be too much volatility in P/NAV, giving rise to potential profits from short-term mean reversion. The closed-end fund literature has some similar findings on stock price deviations from fundamental value, but compared to closed-end funds REITs are much larger and have much higher insider and institutional ownership. These differences suggest that REIT premiums and discounts reflect more than just small investor sentiment, which is a common explanation of why closed-end fund prices deviate from their fundamental value.

Theoretical Analysis of Electronic and Magnetic Properties of NaV2_2O4_4: Crucial Role of the Orbital Degrees of Freedom

Using realistic low-energy model with parameters derived from the first-principles electronic structure calculation, we address the origin of the quasi-one-dimensional behavior in orthorhombic NaV$_2$O$_4$, consisting of the double chains of edge-sharing VO$_6$ octahedra. We argue that the geometrical aspect alone does not explain the experimentally observed anisotropy of electronic and magnetic properties of NaV$_2$O$_4$. Instead, we attribute the unique behavior of NaV$_2$O$_4$ to one particular type of the orbital ordering, which respects the orthorhombic $Pnma$ symmetry. This orbital ordering acts to divide all $t_{2g}$ states into two types: the `localized' ones, which are antisymmetric with respect to the mirror reflection $y \rightarrow -$$y$, and the symmetric `delocalized' ones. Thus, NaV$_2$O$_4$ can be classified as the double exchange system. The directional orientation of symmetric orbitals, which form the metallic band, appears to be sufficient to explain both quasi-one-dimensional character of interatomic magnetic interactions and the anisotropy of electrical resistivity.Comment: 16 pages, 4 figure

Using string-matching to analyze hypertext navigation

A method of using string-matching to analyze hypertext navigation was developed, and evaluated using two weeks of website logfile data. The method is divided into phases that use: (i) exact string-matching to calculate subsequences of links that were repeated in different navigation sessions (common trails through the website), and then (ii) inexact matching to find other similar sessions (a community of users with a similar interest). The evaluation showed how subsequences could be used to understand the information pathways users chose to follow within a website, and that exact and inexact matching provided complementary ways of identifying information that may have been of interest to a whole community of users, but which was only found by a minority. This illustrates how string-matching could be used to improve the structure of hypertext collections

Mastershares: Enigmatic Performance

In this paper we have examined the performance of Mastershares, the first all equity close ended growth fund established by the Unit Trust of India (UTI) in the country, using the various portfolio performance measures that have been suggested in the literature. We found that while in terms of return on the Net Asset Value (NAV) the fund has out-performed the market, in terms of returns based on Market Prices it has shown a mixed performance. On further investigation, we inferred that the excellent performance in terms of NAV could neither be ascribed to selectivity nor to timing of decisions. The explanation possibly lies in UTI’s acquisition of stocks in the primary market as well below prevailing market prices and in the manner of allocation of stocks to various funds managed by the Trust. Our analysis also revealed that the market quite irrationally inflates the volatility of the market price of Mastershares as compared to the volatility observed in the NAV. This observation which implies market inefficiency is in line with the recent researches done in the developed capital markets.

Charge order induced by electron-lattice interaction in NaV2O5

We present Density Matrix Renormalization Group calculations of the ground-state properties of quarter-filled ladders including static electron-lattice coupling. Isolated ladders and two coupled ladders are considered, with model parameters obtained from band-structure calculations for $\alpha^\prime$-NaV$_2$O$_5$. The relevant Holstein coupling to the lattice causes static out-of-plane lattice distortions, which appear concurrently with a charge-ordered state and which exhibit the same zigzag pattern observed in experiments. The inclusion of electron-lattice coupling drastically reduces the critical nearest-neighbor Coulomb repulsion $V_c$ needed to obtain the charge-ordered state. No spin gap is present in the ordered phase. The charge ordering is driven by the Coulomb repulsion and the electron-lattice interaction. With electron-lattice interaction, coupling two ladders has virtually no effect on $V_c$ or on the characteristics of the charge-ordered phase. At V=0.46\eV, a value consistent with previous estimates, the lattice distortion, charge gap, charge order parameter, and the effective spin coupling are in good agreement with experimental data for NaV$_2$O_5$.Comment: 7 pages, 9 figure