Susceptibility ofHeliothis zea (Boddie) larvae toNomuraea rileyi (Farlow) Samson

To determine the impact of α-tomatine at the third trophic level, the following model was developed:Nomuraea rileyi (Farlow) Samson, the secondary consumer, acting onHeliothis zea (Boddie), the primary consumer, fed an artificial diet modified with α-tomatine. In vitro, the allelochemical inhibited colony formation and growth of the fungus. The in vivo test revealed that larval growth and developmental time were affected by α-tomatine andN. rileyi. Detrimental effects on pupal development were observed in larvae fed diet containing α-tomatine and also treated withN. rileyi (LC₉₀). The fungus was detected in the hemolymph and tissue of larvae treated with two lethal concentrations (LC₅₀ and LC₉₀) ofN. rileyi, including those fed α-tomatine. At the LC₅₀, α-tomatine protected larvae againstN. rileyi and increased survivorship; at the LC₉₀, it inhibited the development ofN. rileyi, thereby reducing production of conidia. Thus, the allelochemical α-tomatine retains its antifungal qualities beyond the second trophic level, inhibiting the development ofN. rileyi inH. zea.     

Chitosan-based hydrogels: Synthesis and characterization

Chitosan (CHI) is a polysaccharide of beta-1,4-linked 2-amino-2-deoxy-D-glucopyranose derived by N-deacetylation of chitin in aqueous alkaline medium. The shells of crustaceans such as crabs, shrimp, and lobster are the current source of chitosan. It is known to be non-toxic, odourless, biocompatible in animal tissues and enzymatically biodegradable. For these reasons much research interest has been paid to its biomedical, ecological, and industrial applications over the past decade. However, its rigid crystalline structure, poor solubility in organic solvents and poor processability have limited its use. To broadening its range of applications, a growth research effort has been devoted to explore ways of modifying Chitosan. Here it has been reported on the synthesis of new hydrogels, obtained by self-curing chitosan with acrylic acid (AA) and methyl acrylate (MA). The hydrogels were characterized by FTIR, swelling and rheological analysis. The results of this study showed that the swelling and mechanical properties of chitosan are highly improved by the presence of poly acrylate. The swelling degree of these materials does not depend upon the ratio MA/AA. It is possible to improve and modulate the mechanical properties of the hydrogels by changing the relative MA/AA ratio.     

Extending model checkers for hybrid system verification: the case study of SPIN

A hybrid system is a system that evolves following a continuous dynamic, which may instantaneously change when certain internal or external events occur. Because of this combination of discrete and continuous dynamics, the behaviour of a hybrid system is, in general, difficult to model and analyse. Model checking techniques have been proven to be an excellent approach to analyse critical properties of complex systems. This paper presents a new methodology to extend explicit model checkers for hybrid systems analysis. The explicit model checker is integrated, in a non‐intrusive way, with some external structures and existing abstraction libraries, which store and manipulate the abstraction of the continuous behaviour irrespective of the underlying model checker. The methodology is applied to SPIN using Parma Polyhedra Library. In addition, the authors are currently working on the extension of other model checkers. Copyright © 2013 John Wiley & Sons, Ltd.     

Selective-Targeted Effect of High-Pressure Processing on Proteins Related to Quality: a Proteomics Evidence in Atlantic Mackerel (Scomber scombrus)

The effect of high hydrostatic pressure (HHP) treatment (150, 300, and 450 MPa for 0, 2.5, and 5 min) on total sodium dodecyl sulfate (SDS)-soluble and sarcoplasmic proteins in frozen (?10 °C for 3 months) Atlantic mackerel (Scomber scombrus) was evaluated. Proteomics tools based on image analysis of SDS-polyacrylamide gel electrophoresis (SDS-PAGE) protein gels and protein identification by tandem mass spectrometry (MS/MS) were applied. Total SDS-soluble proteins, composed in high proportion of myofibrillar proteins, were stable under pressurization treatment in terms of solubility and electrophoretic gel profiles. However, pressurization reduced sarcoplasmic proteins’ solubility, modified their one-dimensional (1-D)/two-dimensional (2-D) SDS-PAGE patterns in a direct-dependent manner, and exerted a selective effect on particular sarcoplasmic proteins depending on processing conditions. Thus, protein bands assigned to creatine kinase, fructose-bisphosphate aldolase A, glycogen phosphorylase, and β-enolase were degraded at 300–450 MPa. Additionally, the stability of triosephosphate isomerase B, phosphoglucomutase, and phosphoglycerate kinase-1 was found to be HHP-reduced when submitted at 450 MPa. HHP processing (300–450 MPa) also induced a cross-linking product formation of pyruvate kinase and two compounds derived from tropomyosin at 450 MPa. Frozen storage time of pressurized samples induced an additional lessening in protein solubility, but electrophoretic patterns were not modified. The present investigation emphasizes the higher lability of sarcoplasmic proteins under HHP treatment and the important role of these proteins in the sensory quality enhancement provided by milder HHP conditions on frozen mackerel. HHP technology is expected to boost the development of novel tailored processing approaches to tackle food quality challenges.     

Factorized solution of generalized stable Sylvester equations using many-core GPU accelerators

The Journal of Supercomputing - We investigate the factorized solution of generalized stable Sylvester equations such as those arising in model reduction, image restoration, and observer design....     

Stability and seismic analyses of leaning towers: the case of the minaret in Jam

The leaning Minaret of Jam, one of the tallest in the world, was declared as the Afghanistan's first World Heritage Site by UNESCO in 2002. The global stability analysis of the tower against soil collapse is first evaluated in the present configuration, in the hypothesis of increasing bending moment at the base section, assuming elastic‐perfect plastic behavior for the soil. Then, a finite element model is set up, which is used for the modal analysis and then for the seismic push‐over analysis, based on both single and multi‐modal approaches. Copyright © 2014 John Wiley & Sons, Ltd.     

QoS Mechanisms for the MAC Protocol of IEEE 802.11 WLANs

There are two essential ingredients in order for any telecommunications system to be able to provide Quality-of-Service (QoS) guarantees: connection admission control (CAC) and service differentiation. In wireless local area networks (WLANs), it is essential to carry out these functions at the MAC level. The original version of IEEE 802.11 medium access control (MAC) protocol for WLANs does not include either function. The IEEE 802.11e draft standard includes new features to facilitate and promote the provision of QoS guarantees, but no specific mechanisms are defined in the protocol to avoid over saturating the medium (via CAC) or to decide how to assign the available resources (via service differentiation through scheduling). This paper introduces specific mechanisms for both admission control and service differentiation into the IEEE 802.11 MAC protocol. The main contributions of this work are a novel CAC algorithm for leaky-bucket constrained traffic streams, an original frame scheduling mechanism referred to as DM-SCFQ, and a simulation study of the performance of a WLAN including these features. This work has been partly funded by the Mexican Science and Technology Council (CONACYT) through grant 38833-A. José R. Gallardo received the B.Sc. degree in Physics and Mathematics from the National Polytechnic Institute in Mexico City, the M.Sc. degree in Electrical Engineering from CICESE Research and Graduate Education Center in Ensenada, Mexico, and the D.Sc. degree in Electrical Engineering from the George Washington University, Washington, DC. From 1997 to 2000 he worked as a Research Associate at the Advanced Communications Engineering Centre of the University of Western Ontario, London, Ontario, Canada. From May to December 2000, he worked as a Postdoctoral Fellow at the Broadband Wireless and Internetworking Research Laboratory of the University of Ottawa. Since December 2000, Dr. Gallardo has been with the Electronics and Telecommunications Department of CICESE Research Center, where he is a full professor. His main areas of interest are traffic modeling, traffic control, as well as simulation and performance evaluation of broadband communications networks, with recent emphasis on wireless local area networks (WLANs) and wireless sensor networks (WSNs). Paúl Medina received the B.Eng. degree from the Sonora Institute of Technology, Obregon, Mexico, and the M.Sc. degree from CICESE Research and Graduate Education Center, Ensenada, Mexico, both in Electrical Engineering. From July to September 2005, he worked as a Research Associate at the Broadband Wireless and Internetworking Research Laboratory of the University of Ottawa, Canada. Mr. Medina is currently with CENI²T, Ensenada, Mexico, working as a lead engineer in projects related to routing and access control in wireless sensor networks, as well as IP telephony over wireless LANs. Weihua Zhuang received the B.Eng. and M.Eng. degrees from Dalian Maritime University, Liaoning, China, and the Ph.D. degree from the University of New Brunswick, Canada, all in electrical engineering. Since October 1993, she has been with the Department of Electrical and Computer Engineering, University of Waterloo, ON, Canada, where she is a full professor. She is a co-author of the textbook Wireless Communications and Networking (Prentice Hall, 2003). Dr. Zhuang received the Outstanding Performance Award in 2005 from the University of Waterloo, and the Premier’s Research Excellence Award in 2001 from the Ontario Government. She is an Editor/Associate Editor of IEEE Transactions on Wireless Communications, IEEE Transactions on Vehicular Technology, EURASIP Journal on Wireless Communications and Networking, and International Journal of Sensor Networks. Her current research interests include multimedia wireless communications, wireless networks, and radio positioning.