Viability of subitaneous eggs of the copepod, Acartia tonsa (Dana), following exposure to various cryoprotectants and hypersaline water

Subitaneous eggs were obtained from monocultures of the calanoid copepod Acartia tonsa (Dana), Gulf of Mexico strain. Eggs were exposed to methanol, ethylene glycol, propylene glycol, glycerine, and DMSO at 0.0, 0.1, 0.5, 1.0, 2.0, and 5.0 M and hypersaline water at 50, 75, 100, 150, and 200 g/L. Treatments were evaluated after 10 and 20 min of exposure and at 4 and 26 °C. Viability (percent hatched) was determined after 24 h of incubation in 35 g/L saltwater at 26 °C. Methanol, ethylene glycol, and glycerine had high viability up to 2M, and all experienced large decreases at 5M when the exposure temperature was 26 °C compared to 4 °C. Eggs exposed to propylene glycol had lower mean viability with greater variability at the lower concentrations although viability was greater than 81.4% at 2 M. Significant decreases in viability were observed at 5 M, and the decreases were much greater at an exposure temperature of 26 °C versus 4 °C. DMSO exposed at 26 °C produced high viability up to 1 M before significant decreases occurred, while an exposure temperature of 4 °C produced high viability up to 2 M. Viability of eggs exposed to hypersaline water of 50, 75, and 100 g/L were not significantly different from controls for all treatment combinations except the 26 °C temperature exposed for 20 min, which was significantly lower at 100 g/L. Concentrations of 150 and 200 g/L produced very few to no viable eggs. These results indicate further research is justified to investigate if viability of A. tonsa eggs can be protected by these cryoprotectants and hypersaline water after exposure to cryopreservation conditions

Comment on "Geometric phases for mixed states during cyclic evolutions"

It is shown that a recently suggested concept of mixed state geometric phase in cyclic evolutions [2004 {\it J. Phys. A} {\bf 37} 3699] is gauge dependent.Comment: Comment to the paper L.-B. Fu and J.-L. Chen, J. Phys. A 37, 3699 (2004); small changes; journal reference adde

Update on Laboratory Diagnosis and Epidemiology of \u3cem\u3eTrichomonas vaginalis\u3c/em\u3e: You Can Teach an “Old” Dog “New” Trichs

Past viewpoints on Trichomonas vaginalis infection have characterized the associated clinical disease as a “nuisance” condition, with affected demographics largely being older African American females residing in urban centers. The advent of commercial molecular assays specific for T. vaginalis has offered a new outlook on trichomoniasis. Within high-prevalence sexually transmitted infection populations, parasite distribution is not localized to specific population centers, and T. vaginalis prevalence is elevated among both younger and older age groups. Adaptation of these molecular assays can additionally facilitate male screening and subsequent epidemiologic characterization. These findings, combined with associations between T. vaginalis infection and human immunodeficiency virus (HIV) acquisition/transmission and persistent human papillomavirus infection, support consideration of the expansion of T. vaginalis screening efforts in the realms of clinical practice and public health

PushPush and Push-1 are NP-hard in 2D

We prove that two pushing-blocks puzzles are intractable in 2D. One of our constructions improves an earlier result that established intractability in 3D [OS99] for a puzzle inspired by the game PushPush. The second construction answers a question we raised in [DDO00] for a variant we call Push-1. Both puzzles consist of unit square blocks on an integer lattice; all blocks are movable. An agent may push blocks (but never pull them) in attempting to move between given start and goal positions. In the PushPush version, the agent can only push one block at a time, and moreover when a block is pushed it slides the maximal extent of its free range. In the Push-1 version, the agent can only push one block one square at a time, the minimal extent---one square. Both NP-hardness proofs are by reduction from SAT, and rely on a common construction.Comment: 10 pages, 11 figures. Corrects an error in the conference version: Proc. of the 12th Canadian Conference on Computational Geometry, August 2000, pp. 211-21

Robustness of Gaussian Hedges and the Hedging of Fixed Income Derivatives

The effect of model and parameter misspecification on the effectiveness of Gaussian hedging strategies for derivative financial instrumens is analyzed, showing that Gaussian hedges in the "natural" hedging instruments are particularly robust. This is true for all models that imply Balck/Scholes - type formulas for option prices and hedging strategies. In this paper we focus on the hedging of fixed income derivatives and show how to apply these results both within the framework of Gaussian term structure models as well as the increasingly popular market models where the prices for caplets and swaptions are given by the corresponding Black formulas. By explicitly considering the behaviour of the hedging strategy under misspecification we also derive the El Karoui, Jeanblanc-Picque and Shreve (1995, 1998) and Avellaneda, Levy and Paras (1995) results that a superhedge is obtained in the Black/Scholes model if the misspecified volatility dominates the true volatility. Furthermore, we show that the robustness and superhedging result do not hold if the natural hedging instruments are unavailable. In this case, we study criteria for the optimal choice from the instruments that are available.

Aspects of Favorable Propagation in Massive MIMO

Favorable propagation, defined as mutual orthogonality among the vector-valued channels to the terminals, is one of the key properties of the radio channel that is exploited in Massive MIMO. However, there has been little work that studies this topic in detail. In this paper, we first show that favorable propagation offers the most desirable scenario in terms of maximizing the sum-capacity. One useful proxy for whether propagation is favorable or not is the channel condition number. However, this proxy is not good for the case where the norms of the channel vectors may not be equal. For this case, to evaluate how favorable the propagation offered by the channel is, we propose a ``distance from favorable propagation'' measure, which is the gap between the sum-capacity and the maximum capacity obtained under favorable propagation. Secondly, we examine how favorable the channels can be for two extreme scenarios: i.i.d. Rayleigh fading and uniform random line-of-sight (UR-LoS). Both environments offer (nearly) favorable propagation. Furthermore, to analyze the UR-LoS model, we propose an urns-and-balls model. This model is simple and explains the singular value spread characteristic of the UR-LoS model well

Shifting Data Collection from a Fixed to an Adaptive Sampling Paradigm

For domains where data are difficult to obtain due to human or resource limitations, an emphasis is needed to efficiently explore the dimensions of information spaces to acquire any given response of interest. Many disciplines are still making the transition from brute force, dense, full factorial exploration of their information spaces to a more efficient design of experiments approach; the latter being in use successfully for many decades in agricultural and automotive applications. Although this transition is still incomplete, groundwork must be laid for incorporating the next generation of algorithms to adaptively explore the information space in response to data collected, as well as any resulting empirical models (i.e., metamodels). The methodology in the present work was to compare metamodel quality using a fixed sampling technique compared to an adaptive sampling technique based on metamodel variance. In order to quantify metamodeling errors, a delta method was used to provide quantitative model variance estimates. The present methodology was applied to a design space with an air-breathing engine performance response. It was shown that competitive metamodel quality with lower associated error could be achieved for an adaptive sampling technique for the same level of effort as a fixed, a priori sampling technique

Newspaper Theft, Self-Preservation and the Dimensions of Censorship

One of the most common yet understudied means of suppressing free expression on college and university campuses is the theft of freely-distributed student publications, particularly newspapers. This study examines news accounts of nearly 300 newspaper theft incidents at colleges and universities between 1995 and 2008 in order to identify the manifestations and consequences of this peculiar form of censorship, and to augment existing research on censorship and tolerance by looking, not at what people say about free expression, but at what they do when they have the power of censorship in their own hands. Among the key findings is that men commit nearly 70% of newspaper thefts, which is inconsistent with much of the existing research on censorship and gender, and that those who censor college newspapers are far more concerned with their own self-preservation than with shaping public dialog on controversial social or political issues