A model and temporal proof system for networks of processes

An approach is presented for modeling networks of processes that communicate exclusively through message passing. A process (or a network) is defined by its set of possible behaviors, where each behavior is an abstraction of an infinite execution sequence of the process. The resulting model is simple and modular and facilitates information hiding. It can describe both synchronous and asynchronous networks. It supports recursively-defined networks and can characterize liveness properties such as progress of inputs and outputs, termination, and deadlock.A sound and complete temporal proof system based on the model is presented. It is compositional — a specification of a network is formed naturally from specifications of its components.Van Nguyen received a B.S. degree from Monash University in 1982, an M.S. degree from Cornell University in 1983 and a Ph.D. degree from Cornell University in 1985. He has accepted a research position at the IBM Thomas J. Watson Research Center. His research interests include logics and semantics of programs, programming languages, program synthesis and distributed computing.David Gries received a Ph.D. (actually, a Dr. rer. nat.) from the Munich Institute of Technology (Germany) in 1966. He was an assistant professor at Stanford from 1966 to 1969 and has been on the faculty of Computer Science at Cornell since 1969, where he is presently chairman of the department. He is known for his research in compilers (he is a co-author of the Alcor-Illinois 7090 Algol compiler, finished in 1964), for his research in programming methodology, and for his texts Compiler Construction for Digital Computers (1971) and Science of Programming (1981). He was a Guggenheim Fellow in 1984–85.Susan Owicki received the B.S. degree in mathematics from Michigan State University in 1968. She then attended Cornell University as an NSF Fellow, receiving the M.S. and Ph.D. degrees in computer science in 1970 and 1975, respectively. From 1975 to 1976 she was an Assistant Professor in the Department of Computer Science at Cornell University. Since then she has been a member of the Department of Electrical Engineering at Stanford University, where she is currently an Associate Professor.Dr. Owicki's research in the area of concurrent programming has included work in program verification, programming languages and methodology, and design of algorithms for concurrent systems. She has been particularly interested in problems in computer networks and distributed systems.This work was supported by the NSF under grants MCS-81-03605, DCR-83-202-74, and DCR-83-123-19; by NASA under contract NAGW419; and by the third author's Guggenheim FellowshipThis paper is based on part of the first author's Ph.D. thesis     

An overview on fabrication methods for polymer optical fibers

An overview of the most important materials and fabrication methods for polymer optical fibers is given. In addition to conventional fabrication methods a newly developed continuous melt spinning process for graded‐index fibers is presented that uses rapid cooling in a water quench for the profile formation. The approaches presented are divided into continuous and discontinuous processes for step‐ and graded‐index profile fibers as well as microstructured polymer optical fibers. The methods are described in detail and discussed concerning their efficiency, quality of produced fibers and scalability. © 2014 Society of Chemical Industry     

Reproductive Character Displacement in Lymantria monacha from Northern Japan?

Our objective was to test the hypothesis that the pheromone blend and/or diel periodicity of pheromonal communication differ in populations of the nun moth, Lymantria monacha(Lepidoptera: Lymantriidae), from eastern Asia (northern Honshu, Japan) and Central Europe (Bohemia, Czech Republic). Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extract of female L. monachafrom Japan confirmed the presence of compounds previously identified in pheromone extracts of L. monachafrom Bohemia, as follows: (Z)-7-octadecene, 2-methyl-(Z)-7-octadecene (2me-Z7–18Hy), cis-7,8-epoxy-octadecane (monachalure), and cis-7,8-epoxy-2-methyloctadecane (disparlure). Field experiments in Honshu suggested that (+)-monachalure is the major pheromone component of L. monacha. 2me-Z7–18Hy significantly enhanced attractiveness of (+)-monachalure. Addition of (+)-disparlure to (+)-monachalure plus 2me-Z7–18Hy in Honshu and Bohemia increased attractiveness of lures by 1.2 and 20 times, respectively, indicating that (+)-disparlure is of least and most significance in the respective L. monachapopulations. Moreover, capture of male L. monachain pheromone-baited traps between 18:00 and 24:00 hr in Bohemia and 2:00 and 5:00 hr in Honshu revealed a markedly different diel periodicity of pheromonal communication. Pheromonal communication late at night and use of (+)-monachalure, rather than (+)-disparlure, as the major pheromone component by L. monachain Honshu may have resulted from interspecific competition with coseasonal L. fumida, which uses the early night for pheromonal communication and (+)-disparlure as major pheromone component. Whether communication channel divergence of L. monachain Honshu indeed constitutes a case of reproductive character displacement is difficult to prove. The evolution of such divergence in sympatricpopulations of L. fumidaand L. monachawould have to be demonstrated.     

Populations of the Gall Midge Dasineura oxycoccana on Cranberry and Blueberry Produce and Respond to Different Sex Pheromones

We identified and field-tested the sex pheromones of Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae) midges collected from cranberry, Vaccinium macrocarpon Aiton, and from highbush blueberry, Vaccinium corymbosum L., commonly named cranberry tipworm (CTW) and blueberry gall midge (BGM), respectively. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of pheromone gland extract from the ovipositor of calling CTW females revealed one component (<10 pg per ovipositor/pheromone gland) that elicited antennal responses from CTW males. Stepwise identification was based on its mass spectrum in a concentrated sample with 300 pheromone gland equivalents, retention indices (RI) on three GC columns (DB-5, DB-23, and DB 210), RI inter-column differentials, and RIs and double bond positions of other midge pheromones. These analyses indicated that (8Z)-2,14-diacetoxy-8-heptadecene (2,14-8Z-17) was the candidate pheromone of the CTW. GC-EAD analysis of pheromone gland extract from calling BGM females revealed two components that elicited antennal responses from BGM males. Retention times on the three GC columns were consistent with 2,14-8Z-17 and 2,14-17, indicating that these were candidate pheromone components of the BGM. The four stereoisomers of 2,14-8Z-17 were stereoselectively synthesized and field-tested in cranberry. Delta-type traps baited with SS-2,14-8Z-17 captured significantly more CTW males than did traps baited with any other single stereoisomer or with all four stereoisomers combined. In blueberry, delta-type traps baited with RR-2,14-8Z-17 captured significantly more BGM males than did traps baited with any other single stereoisomer or with all four stereoisomers combined. Subsequent field experiments demonstrated that RR-2,14-17 is the major pheromone component of BGM, and that RR-2,14-8Z-17 is a pheromone component that does not enhance attractiveness of RR-2,14-17. The BGM pheromone RR-2,14-17 has no antagonistic effect on the CTW pheromone SS-2,14-8Z-17 and vice versa. Our results substantiate the conclusion that populations of D. oxycoccana on cranberry and blueberry represent two cryptic species.     

Evidence for Four-Component Close-Range Sex Pheromone in the Parasitic Wasp Glyptapanteles flavicoxis

Females of the parasitic wasp Glyptapanteles flavicoxis (Hymenoptera: Braconidae) deposit a close-range sex pheromone from their abdominal tip that attracts conspecific males and elicits wing-fanning behavior. In this study, we isolated the pheromone components and determined their role in the males' behavior. In coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of the females' body extract, four components (below GC detection) elicited strong responses from male antennae. Monitored by GC-EAD, the components were separated by flash silica gel and high-performance liquid chromatography. Y-tube olfactometer experiments with one or more components revealed that all are necessary to elicit short-range attraction and wing-fanning responses by males. These components remained below detection threshold of the mass spectrometer (∼10 pg) even when 4500 female equivalents were analyzed in a single injection, which attests to the potency of the pheromone and the insects' sensitivity to it.     

Does Pheromone Biology of Lambdina athasaria and L. pellucidaria Contribute to Their Reproductive Isolation?

Recently, 7-methylheptadecane and 7,11-dimethylheptadecane have been reported as sex pheromone components of both spring hemlock looper (SHL), Lambdina athasaria, and pitch pine looper (PPL), Lambdina pellucidaria. Our objective was to test the hypothesis that SHL and PPL are reproductively isolated, in part, through species specificity in: (1) absolute configuration of pheromone components, (2) diel periodicity of pheromonal communication, and/or (3) seasonal flight period. In coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized (7S)- and (7R)-7-methylheptadecane [7S; 7R] as well as (7S,11S)-, (7R,11R)-, and (meso-7,11)-7,11-dimethylheptadecane [7S,11S; 7R,11R; meso-7,11], only 7S and meso-7,11 elicited responses by male SHL and PPL antennae. In field experiments, male SHL and PPL were attracted only to lures containing 7S plus meso-7,11. In hourly recordings of trap-captured males, SHL and PPL in their respective habitats were trapped between 24:00 and 03:00 hr. Capture of both SHL and PPL in pheromone-baited traps throughout June indicated overlapping seasonal flight periods. These findings of identical absolute configuration of pheromoal components, diel periodicity of pheromonal communication, and overlap of seasonal flight periods support synonymy of SHL and PPL. Finite taxonomic classification of PPL and SHL must await careful assessment of further criteria, such as morphometrics, molecular comparisons and ecological analyses.     

Functionally modified,melt‐electrospun thermoplastic polyurethane mats for wound‐dressing applications

The electrospinning of a polymer melt is an interesting process for medical applications because it eliminates the cytotoxic effects of solvents in the electrospinning solution. Wound dressings made from thermoplastic polyurethane (TPU), particularly as a porous structured electrospun membrane, are currently the focus of scientific and commercial interest. In this study, we developed a functionalized fibrillar structure as a novel antibacterial wound‐dressing material with the melt‐electrospinning of TPU. The surface of the fibers was modified with poly(ethylene glycol) (PEG) and silver nanoparticles (nAg's) to improve their wettability and antimicrobial properties. TPU was processed into a porous, fibrous network of beadless fibers in the micrometer range (4.89 ± 0.94 μm). The X‐ray photoelectron spectroscopy results and scanning electron microscopy images confirmed the successful incorporation of nAg's onto the surface of the fiber structure. An antibacterial test indicated that the PEG‐modified nAg‐loaded TPU melt‐electrospun structure had excellent antibacterial effects against both a Gram‐positive Staphylococcus aureus strain and Gram‐negative Escherichia coli compared to unmodified and PEG‐modified TPU fiber mats. Moreover, modification with nAg's and PEG increased the water‐absorption ability in comparison to unmodified TPU. The cell viability and proliferation on the unmodified and modified TPU fiber mats were investigated with a mouse fibroblast cell line (L929). The results demonstrate that the PEG‐modified nAg‐loaded TPU mats had no cytotoxic effect on the fibroblast cells. Therefore, the melt‐electrospun TPU fiber mats modified with PEG and nAg have the potential to be used as antibacterial, humidity‐managing wound dressings. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40132.     

Experimental and kinetic studies of C–H–O plasmas for polycrystalline and nano-smooth diamond deposition

CO₂–CH₄ and CO–H₂ plasmas were studied by optical emission spectroscopy, microwave interferometry, Langmuir probing and molecular beam mass spectrometry. The variations of the plasma parameters as well as the concentration variations of both stable species and radicals were obtained as a function of the inlet composition. A modelling of the plasma kinetics taking into account the coupled hydrodynamics of the gaseous species and the gas phase chemistry including electron dissociation and surface recombination at the reactor wall was carried out. These experimental and modelling studies were used for correlating the influence of the relative concentration of important gaseous species in the plasma to the deposition domain, the structure (polycrystalline or nano-smooth) and the quality of diamond films which are deposited at moderate temperature. The influence of the concentrations of both hydrocarbon radicals and H and OH species is especially evidenced. The growth of nano-smooth diamond films relatively to polycrystalline ones is explained.     

Sex Pheromone Components of Pitch Pine Looper, Lambdina pellucidaria

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are sex pheromone components of female pitch pine looper (PPL), Lambdina pellucidaria. Compounds extracted from the pheromone glands of female moths were identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) and coupled GC–mass spectrometry (GC-MS) in selected ion monitoring mode. In field-trapping experiments, 7 and 7,11 in combination, but not singly, attracted numerous male moths. 5,11-Dimethylheptadecane (5,11) was detected by GC-EAD in female PPL pheromone gland extract, but did not significantly increase attraction of PPL males to 7 plus 7,11. Although 7 was > 10 times more abundant than 7,11 in pheromone gland extracts, traps baited with synthetic 7 plus 7,11 at a blend ratio of 1:1, rather than 1:0.1 or 1:0.01, captured the most PPL males. The chemical communication of PPL and spring hemlock looper (SHL), Lambdina athasaria, is strikingly similar. Both species employ 7 plus 7,11 as sex pheromone. Restriction of SHL to forests with eastern hemlock or balsam fir and PPL to forests with pitch or other hard pines contributes to their reproductive isolation. PPL and SHL may also use different optical isomers of enantiomeric 7 and stereoisomeric 7,11 to maintain specificity of their chemical communication.