Frequency domain stability and boundedness criteria of pulse-modulated feedback systems

Stability and boundedness conditions of pulse modulated feedback systems are derived in this paper. These conditions, based on the frequency domain approach, extend the range of applicability of this approach to systems without the strict sector non-linearity. Geometric interpretations of the results in the Popov plane are also presented.     

Measurement of Lipoxygenase Activity in Homogenized Green Bean Tissue

A polarographic assay was adapted to measure lipoxygenase activity in homogenized vegetable tissue. The method was verified using ground green beans. Km value, pH optimum, and rate of thermal inactivation of lipoxygenase were measured in macerated green bean seed samples and compared with published values. In general our results using homogenized samples were similar to published reports for purified green bean lipoxygenase. We observed that ionic strength, pH, and dibasic phosphate concentration must be properly controlled in the assay of lipoxygenase.     

PARENTAL SCHEMATA IN EMOTIONALLY DISTURBED WOMEN.

30 FEMALE PSYCHIATRIC PATIENTS WERE ADMINISTERED THE MMPI AND A MODIFICATION OF KUETHE'S METHOD FOR INVESTIGATING SOCIAL SCHEMATA IN WHICH SS PLACE MAGNETS REPRESENTING "MOTHER," "FATHER," AND SIGNIFICANT OTHERS ON A BOARD IN RELATION TO A CENTRALLY PLACED "SELF" MAGNET. DISTANCE BETWEEN SELF AND MOTHER MAGNETS (1) WAS CORRELATED WITH INCREASED SCHIZOPHRENIA (SC) AND DECREASED EGO STRENGTH (ES) SCORES ON THE MMPI, (2) WAS GREATER THAN THAT OF CONTROLS (N = 40), AND (3) TENDED TO DECREASE FOLLOWING 6 WK. OF TREATMENT. DISTANCE FROM FATHER WAS NOT SIGNIFICANTLY CORRELATED WITH SC OR ES, AND WAS NOT DIFFERENT FROM THAT OF CONTROLS, BUT INCREASED AFTER THERAPY. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemical Strengthening of Polycrystalline Alumina

Low-expansion solid solution surface layers formed by reaction of Cr₂O₃ and Al₂O₃ were used to chemically strengthen alumina bodies. The surface layers were formed by packing the samples in Cr₂O₃ powder and heating to high temperatures. Fluorides or chlorides were added to the packing material, leading to substantial additional improvement. The flexural strengths of the control samples were increased by refiring in the presence of the products of decomposition of the fluorides. At high concentrations of fluorides in the packing material, the outside dimensions and the weights of the samples decreased during the treatments.     

GENOMIC HARDWIRING AND PHENOTYPIC PLASTICITY OF TERPENOID-BASED DEFENSES IN CONIFERS

Over evolutionary history, conifers have faced a myriad of threats from phloem- and xylem-feeding insects, defoliating insects, and fungal pathogens. Among the trees defenses, terpenoids appear to play a major role by harming, disabling, deterring, repelling, or otherwise reducing the fitness of potential invaders. Each of the three classes of terpenoids in conifers, monoterpenes, sesquiterpenes, and diterpenes, are composed of a large number of representative compounds. In most cases, the presence of a particular terpenoid compound in the oleoresin or volatile emissions from a specific conifer can be accounted for by the expression of one of many committed terpene synthase (TPS) genes. However, while each TPS may produce one or a few major products, many produce a variety of minor products with relatively constant component ratios in the product blends. TPS genes exist in conifers in large and functionally diverse, yet monophyletic, gene families. Within these gene families, new biochemical functions of TPS appear to have evolved by gene duplication and changes in the amino acid sequence of the enzymes active site. In addition, TPS genes may be differentially expressed prior to, during, and following attack by insects or pathogens. Thus, while the production of any particular terpenoid is hardwired into a conifers genome, these trees have the capacity to change the mixture of terpenoids in oleoresin secretions and volatile emissions. Anatomical changes may also accompany induced terpenoid production, supplementing the plasticity of the molecular and biochemical events.     

AN EARLY SUCCESS STORY

Abstract

In 2006, Shieh et al. proposed an efficient remote mutual authentication and key agreement scheme which uses smart cards and requires only hash function operations. In this paper, we show that Shieh et al.'s scheme is vulnerable to guessing attacks, forgery attacks and key compromise attacks. To eliminate these weaknesses, an improvement of Shieh et al.'s scheme with increased security is proposed. The security and efficiency of the improved scheme raises the attractiveness for implementation.     

REVIEW OF THINGS CRYPTOLOGIC

Abstract

Sets out, with comments, an account by A. G. Denniston (the operational head of the British Government Code and Cypher School in 1939) of the meeting near Pyry, Poland, in July 1939, when Polish cryptanalysts revealed how they broke Enigma, and a letter by Dillwyn Knox on the meeting's outcome.     

Mass Transfer and Textural Changes during Processing of Apples by Combined Methods

Mass transfer and textural changes of ‘Red Delicious’ apple slices and cylinders during osmotic adjustment of a_w by the combined method approach were studied at 30, 40 and 50°C. Mass transfer of water and sugar in the treated apple followed typical log-normal behavior with most changes occurring during early stages of the process. The changes followed Crank's equation for diffusion. A negative correlation between apple texture and sugar diffusion was observed. Softening, as well as mass transfer changes, occurred at early stages of osmotic treatment. The texture changes were most pronounced at the edges of the apple tissue where the sugar had penetrated. Softening and sugar uptake were more pronounced when apples were acidified. Apples became firm within 2 hr of the process, when the external layer of the apple cylinders penetrated by sugar was trimmed. Calcium chloride beyond 0.30% minimized tissue softening, but the typical crispy structure of the fresh apple was not restored.     

DEFORMATION TESTING OF FOODS: III. Effect of Size and Shape on the Magnitude of Deformation

Slabs of uniform agar gels were cut into standard shapes of various sizes and their deformation under a small compressive force was measured in an Instron Universal Testing machine. The deformation of rectangular solids and regular cylinders with vertical axes was found to be directly proportional to the specimen height and inversely proportional to the cross-sectional area. The deformation of regular cylinders with horizontal axes was inversely proportional to the length and was a linear function of the diameter. Deformation of spheres first increased to a maximum, then decreased as the diameter increased giving an inverted V-shaped curve. The diameter at which the maximum deformation of spheres occurred depended on the agar concentration in the gel and the magnitude of the deforming force.