Maximal stability robustness for state equations

A measure for stability robustness of a linear time-invariant finite-dimensional system state equations is introduced. An upper bound for the measure is derived using the characteristic values of the system. It is shown that the set of optimal systems, namely, systems for which the stability robustness measure attains the bound, contains the normal set, which has been considered as the set of optimal robustness     

Synthetic Activity of Recombinant Whole Cell Biocatalysts Containing 2-Deoxy-D-ribose-5-phosphate Aldolase from Pectobacterium atrosepticum

In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications.     

Intersensory experience and early perceptual development: Attenuated prenatal sensory stimulation affects postnatal auditory and visual responsiveness in bobwhite quail chicks (Colinus virginianus).

Related experiments examined the effects of attenuated prenatal sensory stimulation on subsequent postnatal auditory and visual responsiveness in precocial bobwhite quail chicks (Colinus virginianus). Results revealed that denying quail embryos the prenatal vestibular and tactile stimulation provided by broodmates during incubation altered pre- and postnatal perceptual functioning. Chicks incubated in physical isolation during the late stages of prenatal development responded to maternal auditory cues into later stages of the postnatal period and failed to respond to maternal visual cues at ages communally incubated chicks typically display such visual responsiveness. In addition, embryos incubated in physical isolation failed to exhibit early auditory learning of an individual maternal call, a behavior reliably seen in communally incubated embryos. Taken together, these results and those from related studies indicate that a substantial decrease or increase in the range of sensory stimulation normally present in the prenatal period can result in a slowing of the rate of species specific perceptual development and suggest that some optimal range of prenatal sensory stimulation is necessary for species-typical perceptual capacities to emerge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-modal equivalence in early infancy: Auditory–visual intensity matching.

To examine the hypothesis that young infants ignore differences between lights and sounds and instead respond to auditory and visual stimuli as more or less similar depending on their intensity, a cardiac habituation/dishabituation method with a test for stimulus generalization was employed. In 2 experiments, a total of 40 3-wk-old Ss were repeatedly presented with white-light followed by white-noise stimuli of different intensities. A U-shaped relationship between magnitude of cardiac response (CR) and loudness was found. In view of previous findings that without prior visual stimulation a monotonic increase in CR to the same range of auditory stimuli results, this finding of a significant quadratic relationship with loudness suggests that Ss were responding to the auditory stimuli in terms of their similarity to the previously presented visual stimulus. A separate group of 14 infants presented with a more intense visual stimulus exhibited a shift in the intensity at which a minimal CR occurred. Results of a study with 31 adults did not show any systematic relationship between CR and loudness, indicating that unlike infants, adults do not spontaneously make cross-modal matches of intensity. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Novel Nanoencapsulation Technology and its Potential Role in Bile Acid-Based Targeted Gene Delivery to the Inner Ear

Hearing loss impacts a large proportion of the global population. Damage to the inner ear, in particular the sensitive hair cells, can impact individuals for the rest of their lives. There are very limited options for interventions after damage to these cells has occurred. Targeted gene delivery may provide an effective means to trigger appropriate differentiation of progenitor cells for effective replacement of these sensitive hair cells. There are several hurdles that need to be overcome to effectively deliver these genes. Nanoencapsulation technology has previously been used for the delivery of pharmaceuticals, proteins and nucleic acids, and may provide an effective means of delivering genes to trigger appropriate differentiation. This review investigates the background of hearing loss, current advancements and pitfalls of gene delivery, and how nanoencapsulation may be useful.     

Wigner-Weyl calculus in Keldysh technique

Journal of Computational Electronics - We discuss the non-equilibrium dynamics of condensed matter/quantum field systems in the framework of Keldysh technique. In order to deal with the...     

Perception of auditory–visual temporal synchrony in human infants.

Using a habituation/test procedure, the author investigated adults' and infants' perception of auditory–visual temporal synchrony. Participants were familiarized with a bouncing green disk and a sound that occurred each time the disk bounced. Then, they were given a series of asynchrony test trials where the sound occurred either before or after the disk bounced. The magnitude of the auditory visual temporal asynchrony threshold differed markedly in adults and infants. The threshold for the detection of asynchrony created by a sound preceding a visible event was 65 ms in adults and 350 ms in infants and for the detection of asynchrony created by a sound following a visible event was 112 ms in adults and 450 ms in infants. Also, infants did not respond to asynchronies that exceeded intervals that yielded reliable discrimination. Infants' perception of auditory–visual temporal unity is guided by a synchrony and an asynchrony window, both of which become narrower in development. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The development of intersensory temporal perception: An epigenetic systems/limitations view.

Several theories have stressed the importance of intersensory integration for development but have not identified specific underlying integration mechanisms. The author reviews and synthesizes current knowledge about the early development of intersensory temporal perception and offers a theoretical model based on epigenetic systems theory, proposing that responsiveness to 4 basic features of multimodal temporal experience—temporal synchrony, duration, temporal rate, and rhythm—emerges in a sequential, hierarchical fashion. The model postulates that initial developmental limitations make intersensory synchrony the basis for the integration of intersensory temporal relations and that the emergence of responsiveness to the other, increasingly more complex, temporal relations occurs in a hierarchical, sequential fashion by building on the previously acquired intersensory temporal processing skills. This article focuses on how and under what conditions infants perceive equivalent intersensory temporal relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)