Intrinsic distortion of a fully differential BD-modulated Class-D amplifier with analog feedback

This paper presents a mathematical analysis of a fully differential BD-modulated Class-D amplifier with analog feedback, i.e., one having a bridge-tied-load output configuration with negative feedback and ternary PWM signal. Notwithstanding the highly nonlinear nature of the amplifier's operation, an extremely accurate closed-form expression for the audible output signal is derived and verified based on computer simulations. This expression demonstrates that there exist larger high-order intrinsic distortions (e.g., 5th-order harmonic distortion and intermodulation distortion) for BD-modulation, compared to that for AD-modulation (binary PWM signal). Furthermore, the 3rd-order harmonic distortion has a roughly parabolic response as a function of the magnitude of the input signal and reaches its peak when the modulation index of the input signal is around 0.7. Overall, the BD-modulated Class-D amplifier has a larger intrinsic distortion for small input signal but a smaller intrinsic distortion for large input signal, compared to AD-modulated designs

Phylogenetics of Archerfishes (Toxotidae) and Evolution of the Toxotid Shooting Apparatus

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Archerfishes (Toxotidae) are variously found in the fresh- and brackish-water environments of Asia Pacific and are well known for their ability to shoot water at terrestrial prey. These shots of water are intended to strike their prey and cause it to fall into the water for capture and consumption. While this behavior is well known, there are competing hypotheses (blowpipe vs. pressure tank hypothesis) of how archerfishes shoot and which oral structures are involved. Current understanding of archerfish shooting structures is largely based on two species, Toxotes chatareus and T. jaculatrix. We do not know if all archerfishes possess the same oral structures to shoot water, if anatomical variation is present within these oral structures, or how these features have evolved. Additionally, there is little information on the evolution of the Toxotidae as a whole, with all previous systematic works focusing on the interrelationships of the family. We first investigate the limits of archerfish species using new and previously published genetic data. Our analyses highlight that the current taxonomy of archerfishes does not conform to the relationships we recover. Toxotes mekongensis and T. siamensis are placed in the synonymy of T. chatareus, Toxotes carpentariensis is recognized as a species and removed from the synonymy of T. chatareus, and the genus Protoxotes is recognized for T. lorentzi based on the results of our analyses. We then take an integrative approach, using a combined analysis of discrete hard- and soft-tissue morphological characters with genetic data, to construct a phylogeny of the Toxotidae. Using the resulting phylogenetic hypothesis, we then characterize the evolutionary history and anatomical variation within the archerfishes. We discuss variation in the oral structures and the evolution of the mechanism with respect to the interrelationships of archerfishes, and find that the oral structures of archerfishes support the blowpipe hypothesis but soft-tissue oral structures may also play a role in shooting. Finally, by comparing the morphology of archerfishes to their sister group, we find that the Leptobramidae has relevant shooting features in the oral cavity, suggesting that some components of the archerfish shooting mechanism are examples of co-opted or exapted traits

Serotonergic treatment normalizes midbrain dopaminergic neuron increase after periaqueductal gray stimulation-induced anticipatory fear in a rat mode

Background: Electrical stimulation of the dorsolateral periaqueductal gray (dlPAG) in rats has been shown to elicit panic-like behaviour and can be a useful tool for modelling anticipatory fear and agoraphobia. Methods: In this study, we further analysed our previous data on the effects of escitalopram (a selective serotonin reuptake inhibitor, SSRI) and buspirone (a 5-HT1A receptor partial agonist) on dlPAG-induced anticipatory fear behaviour in a rat model using freezing as a measure. We then used tyrosine hydroxylase (TH) immunohistochemistry to probe the effects on dopaminergic neurons. Results: Although acute treatment of escitalopram, but not buspirone, was effective in reducing anticipatory freezing behaviour, chronic administrations of both drugs were comparably effective. We found that the number of dopaminergic neurons in the ventral tegmental area (VTA) was lowered in both chronic buspirone and escitalopram groups. We showed a strong correlation between the number of dopaminergic neurons and freezing in the VTA. We further showed positive correlations between dopaminergic neurons in the VTA and substantia nigra pars compacta in escitalopram and buspirone groups, respectively. Limitations: Although our data strongly hint to a role of dopaminergic mechanisms in the dlPAG induced fear response, more in-depth studies with larger sample sizes are needed to understand the neuronal mechanisms underlying the interactions between serotonergic drugs and dopaminergic cell number and fear behavior. Conclusion: Chronic treatment with an SSRI and a 5-HT1A agonist decrease the number of dopaminergic neurons in the VTA. These effects seem to be associated with reduced dlPAG-induced anticipatory freezing behaviour

LRRK2 A419V is not associated with Parkinson's disease in different Chinese populations

10.1371/journal.pone.0036123PLoS ONE77

Computer simulated versus observed NO2 and SO2 emitted from elevated point source complex

ISC-AERMOD dispersion model was used to predict air dispersion plumes from an diesel power plant complex. Emissions of NO2 and SO2 from stacks (5 numbers) and a waste oil incinerator were studied to evaluate the pollutant dispersion patterns and the risk of nearby population. Emission source strengths from the individual point sources were also evaluated to determine the sources of significant attribution. Results demonstrated the dispersions of pollutants were influenced by the dominant easterly wind direction with the cumulative maximum ground level concentrations of 589.86 μg/m3 (1 h TWA NO2) and 479.26 μg/m3 (1 h TWA SO2). Model performance evaluation by comparing the predicted concentrations with observed values at ten locations for the individual air pollutants using rigorous statistical procedures were found to be in good agreement. Among all the emission sources within the facility complex, SESB-Power (diesel power plant) had been singled out as a significant source of emission that contributed >85% of the total pollutants emitted

K\"{a}hler-Einstein metrics on strictly pseudoconvex domains

The metrics of S. Y. Cheng and S.-T. Yau are considered on a strictly pseudoconvex domains in a complex manifold. Such a manifold carries a complete K\"{a}hler-Einstein metric if and only if its canonical bundle is positive. We consider the restricted case in which the CR structure on $\partial M$ is normal. In this case M must be a domain in a resolution of the Sasaki cone over $\partial M$. We give a condition on a normal CR manifold which it cannot satisfy if it is a CR infinity of a K\"{a}hler-Einstein manifold. We are able to mostly determine those normal CR 3-manifolds which can be CR infinities. Many examples are given of K\"{a}hler-Einstein strictly pseudoconvex manifolds on bundles and resolutions.Comment: 30 pages, 1 figure, couple corrections, improved a couple example

Rotating day and night disturb growth hormone secretion profiles, body energy metabolism, and insulin levels in mice

Background: Insulin and growth hormone (GH) - 2 vital metabolic regulatory hormones - regulate glucose, lipid, and energy metabolism. These 2 hormones determine substrate and energy metabolism under different living conditions. Shift of day and night affects the clock system and metabolism probably through altered insulin and GH secretion. Methods: Five-week-old male mice were randomly assigned to a rotating light (RL) group (3-day normal light/dark cycle followed by 4-day reversed light/dark cycle per week) and normal light (NL) group. Body weight and food intake were recorded every week. Series of blood samples were collected for pulsatile GH analysis, glucose tolerance test, and insulin tolerance test at 9, 10, and 11 weeks from the start of intervention, respectively. Indirect calorimetric measurement was performed, and body composition was tested at 12 weeks. Expressions of energy and substrate metabolism-related genes were evaluated in pituitary and liver tissues at the end of 12-week intervention. Results: The RL group had an increased number of GH pulsatile bursts and reduced GH mass/burst. RL also disturbed the GH secretion regularity and mode. It suppressed insulin secretion, which led to a disturbed insulin/GH balance. It was accompanied by the reduced metabolic flexibility and modified gene expression involved in energy balance and substrate metabolism. Indirect calorimeter recording revealed that RL decreased the respiratory exchange ratio (RER) and oxygen consumption at the dark phase, which resulted in an increase in fat mass and free fatty acid levels in circulation. Conclusion: RL disturbed pulsatile GH secretion and decreased insulin secretion in male mice with significant impairment in energy, substrate metabolism, and body composition.Diabetes mellitus: pathophysiological changes and therap

Perception Of The Mentor-Mentee System Among Medical Students Of The Faculty Of Medicine And Health Sciences, Universiti Malaysia Sarawak

Objective: To determine the perception of medical students towards mentor-mentee system in Faculty of Medicine and Health Sciences of UNIMAS. Method: It was a cross-sectional study involving all 104 second year and 80 fifth year medical students. A self-administered questionnaire consisting of socio-demographic details, general perceptions on mentor-mentee system, academic support, personal development, and emotional and psychological support was distributed. The data was analysed using the SPSS version 19. Result: Majority of the subjects had a positive outlook towards the mentor-mentee system with a range of 45.6% to 57%. Three of the top rated perceptions were ‘mentor analyses mentee’s examination results and provides constructive feedback’, ‘mentor advises how to improve academic performance’, and ‘mentor gives encouragement and support for the challenges faced’ (66.8%, 68.0% and 62.9% respectively). Pre-cinical medical students had significantly better perception on mentor-mentee system than clinical students (p≤0.002) while those with non-clinician mentors significantly had better perceptions than those with clinician mentors (p≤0.003) on the system. No significant difference was found between the perceptions of males and females for all components (p=0.234 to 0.722). Conclusion: The mentor-mentee system was found to be successful as more than half of the respondents had posititve perception on the system and its aspects. However, pre-clinical students benefited more compared to clinical students, which reflects the need to look at the support given to clinical students. It was recommended that future studies should incorporate the perceptions of mentors

Homoserine and quorum-sensing acyl homoserine lactones as alternative sources of threonine:A potential role for homoserine kinase in insect-stage Trypanosoma brucei

10.1111/mmi.12853Molecular Microbiology951143-15