Theory and Techniques for Synthesizing a Family of Graph Algorithms

Although Breadth-First Search (BFS) has several advantages over Depth-First Search (DFS) its prohibitive space requirements have meant that algorithm designers often pass it over in favor of DFS. To address this shortcoming, we introduce a theory of Efficient BFS (EBFS) along with a simple recursive program schema for carrying out the search. The theory is based on dominance relations, a long standing technique from the field of search algorithms. We show how the theory can be used to systematically derive solutions to two graph algorithms, namely the Single Source Shortest Path problem and the Minimum Spanning Tree problem. The solutions are found by making small systematic changes to the derivation, revealing the connections between the two problems which are often obscured in textbook presentations of them.Comment: In Proceedings SYNT 2012, arXiv:1207.055

Visualization of acoustic intensity vector fields using scanning measurement techniques

Sound propagation paths are not always well understood mainly because of the complex nature of the source or the environment. A direct method to capture the sound energy flow throughout a room is to measure the three-dimensional sound intensity distribution across space. In the past years, several studies have been carried out using step by step measurements with a three-dimensional intensity probe consisting of a sound pressure transducer and three orthogonal particle velocity sensors. The probe’s ability to measure even in highly reverberant environments and its small size are key features required for numerous applications. However, punctual measurements are time-consuming, especially when a large number of measurement positions are evaluated. The use of advanced scanning measurement techniques, such Scan & Paint, allows for the gathering of data across a time stationary sound field in a fast and efficient way, using a single sensor and webcam only. The acoustic signals are acquired manually by moving a probe across a measurement plane whilst filming the event with a camera. In the post-processing stage, the sensor position is extracted and then used for linking a segment of the signal acquired to a certain position of the space. In this manner, the overall measurement time is reduced from hours to minutes. In this paper, the acoustic intensity vector fields of several complex examples are investigated; revealing the acoustic energy flow of several vehicles, a loudspeaker in a room, and also the interaction between an absorbing sample and a reverberant sound field

The effect of dietary soybean isoflavones on the rate and efficiency of growth and carcass muscle content in pigs and rats

The in vitro biological properties of soy isoflavones suggest that they may negatively impact muscle growth in vivo. Three experiments were conducted to determine the impact of dietary soybean isoflavones on body and muscle growth in pigs and rats. In experiment one, pigs were self fed a basal diet containing 0 or 1585 ppm supplemental isoflavones from 6 to 30 kg body weight. The isoflavones source consisted of an extract of soybeans that contained the isoflavones genistein, daidzein, and glycitein in relative proportions and physical forms similar to that present in soybeans. Isoflavones increased (P \u3c .08) daily body weight gain (579 vs 595) and carcass muscle content (12.48 vs 12.87 kg). Increased muscle growth was observed in predominantly red-fibered muscles. In experiment two, pigs were fed diets that contained supplemental genistein concentrations of 0, 200, 400, 600 and 800 ppm from 5 to 28 kg body weight. Serum genistein increased linearly (P \u3c .01) from .55 to 3.44 muM as dietary genistein levels increased independent of stage of growth. Feed intake and body growth rate were decreased by dietary genistein during initial stages of growth, but were increased at later stages of growth in response to increasing dietary genistein. The combined weights of four red and four white muscles at 27 kg body weight, were not altered by dietary genistein concentration. In experiment three, gravid rats were fed a basal diet supplemented with 0, 431, 862 or 1724 ppm isoflavones supplied by a soy extract similar to experiment one. Growth of male offspring was not altered by maternal dietary isoflavones but growth and efficiency of feed utilization of female offspring increased (P \u3c .04) with increasing maternal dietary isoflavone concentration. Hind limb muscle weights of male, but no female offspring, increased (P \u3c .03) with increasing maternal isoflavone concentrations. Based on these data, dietary soy isoflavones increase muscle growth when fed either pre- or postnatally. Further, the inhibitory effects of genistein on muscle growth, which are observed in vitro at concentrations as low as 1.0 muM, are not observed in vivo with serum concentrations as high as 3.4 muM

In Vitro and In Vivo Ocular Studies Using Herpes Simplex Virus Types 1 and 2

The biological properties of three HSV strains were characterized with reference to ocular disease in the rabbit. Two HSV-1 strains, 17 and McKrae, and the HSV-2 strain HG52 were studied and the following parameters were assessed; clinical disease; virulence; spontaneous shedding of HSV; induced shedding of HSV; neural latency; and corneal latency. Intratypic and intertypic differences were apparent. The HSV-l strain 17 was pathogenic to rabbit eyes and neuropathogenic with increasing titres of inoculum. It had a low frequency of spontaneous shedding and an intermediate frequency of induced shedding. The HSV-1 strain 17 was able to establish latent infections within trigeminal ganglia. The HSV-1 strain McKrae was pathogenic to rabbit eyes and particularly neuropathogenic. It had a high frequency of both spontaneous and induced viral shedding. The McKrae strain was able to establish latent infections within trigeminal ganglia but differed in maintaining a latent infection within the cornea. The HSV-2 strain HG52 was non-pathogenic to rabbit eyes and non-neuropathogenic. It had a very low frequency of spontaneous and induced shedding. The HSV-2 strain HG5 2 was able to maintain latent infections within the trigeminal ganglion. Twelve corneas from patients suffering from herpes simplex keratitis were collected and analysed by light microscopy, electron microscopy and organ culture. Two of the twelve corneas released HSV after at least seven days in organ culture. The released virus was identified as HSV-1 by restriction endonuclease analysis. Primary cultures of rabbit corneal epithelial cells, keratocytes and endothelial cells were established. The identity of the cells was confirmed by electron microscopy and indirect immunofluorescence techniques. The one step growth kinetics of HSV-1 in the three distinct cell types were established. Latent infections were established in the distinct cell lines in vitro using supra optimal temperatures. Cellular stress proteins were demonstrated at supraoptimal temperatures. The antiviral agent acycloguanosine was unable to eliminate latent HSV infections at the supraoptimal temperature (4

Surface, Bulk, and Rheological Properties of Polyhedral Oligomeric Silsesquioxane/High Density Polyethylene Nanocomposites

In the formulation of high performance nanocomposites, control of miscibility and dispersion of filler material through a polymer matrix is of utmost importance. Due to their inorganic nature most nanofillers are insoluble in polymers, leading to costly/complicated surface modification as a primary means of increasing miscibility and interaction with organic matrices. Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals offer an attractive alternative to conventional nanofillers. Due to their hybrid organic-inorganic nature, POSS has the potential to be tailored for miscibility in a wide range of organic matrices not by chemical surface modification but through modification of the molecular structure of the filler itself. The overall goal of this research is to investigate how changes to POSS molecular structure affect miscibility and dispersion in physically blended high density polyethylene (HDPE)/POSS blends. The primary objective of the first section is to understand the effect of POSS cage structure, physical state and R-group alkyl chain length on miscibility and blend performance through a wide range of characterization techniques. Special attention will be paid to rheological, bulk and surface performance of the blends as compared to the neat HDPE matrix. The primary objective of the second section is to determine the utility of theoretical solubility parameter calculations as a means of predicting POSS miscibility in the HDPE matrix. This section will focus on solubility parameters calculated using both group contribution and molecular dynamics simulation methods, determining their proximity to each other, and qualifying their applicability in predicting POSS miscibility and blend performance. This dissertation is comprised of six chapters Chapter I provides an introduction to nanocomposites, as well as background information on HDPE, POSS, pertinent POSS blends and solubility parameter theory. Chapter II gives an overview of the research goals and specific objectives of this research. Chapter III probes the influence of POSS functionality, cage structure and physical state on the bulk properties (thermal, rheological, mechanical) of the melt-processed HDPE/POSS blends. Chapter IV explores HDPE surface modification as a function of POSS incorporation, as well as aggregation and migrational behavior of the POSS molecules. Chapter V surveys POSS theoretical solubility parameter calculations via both group contribution theory and molecular dynamics simulations and correlates these values with observed blend behavior due to incorporation of POSS. Finally, Chapter VI provides recommendations for future work in an attempt to further refine our understanding of the complex behaviors and trends observed in our HDPE/POSS systems

The Changing Face of Milk Production, Milk Quality and Milking Technology in Brazil

This introductory paper gives an overview of milk production in Brazil and discusses a series of recent regulations implemented to improve milk quality with the purpose of asserting the Brazilian dairy industry as a competitor on the international market. It also points out the economic advantage of setting design guidelines for milking machines that would be best suited to Brazilian crossbred cows.Brazilian Milk Quality, Brazil Dairy Industry, Brazilian Milk Production, Brazilian Milk Prices, Agribusiness, Farm Management, Food Consumption/Nutrition/Food Safety, Industrial Organization, International Development, Political Economy,

Web accessibility: how does your state eye up?

Since the passage of Section 508 federal law, several states have instituted their own web accessibility policy. Many have not instituted a policy. This paper compares U.S. web site accessibility with the quality of state web site policies. The results show a disparity between policy, adherence, and practice