Hopf Bifurcation and Chaos in a Single Inertial Neuron Model with Time Delay

A delayed differential equation modelling a single neuron with inertial term is considered in this paper. Hopf bifurcation is studied by using the normal form theory of retarded functional differential equations. When adopting a nonmonotonic activation function, chaotic behavior is observed. Phase plots, waveform plots, and power spectra are presented to confirm the chaoticity.Comment: 12 pages, 7 figure

Variation of Manning’s coefficient with channel stage

Although Manning's roughness coefficient is known to vary with river stage, information on this aspect is limited, and practitioners have to resort to trial-and-error approaches or rely on their judgment to quantify the variation. This research was aimed at investigating the variation patterns of Manning's roughness coefficient over depth. Investigators conducted an extensive laboratory experiment using a fairly long and large channel, in the shape of half of a compound cross section, to simulate natural rivers. This experimental channel allowed a comprehensive investigation of both uniform and composite roughness elements along the channel's wetted perimeter. Data were taken from both cases: when flow was restricted in the main channel (to simulate a prismatic channel) and when it covered the floodplain. In addition, the investigators converted data from other researchers to verify factors not covered in this study. The researchers found that while geometry and roughness patterns can both affect the magnitude of Manning's coefficient over depth, the effects vary in prismatic and floodplain channels. Experimental data were used to identify the variation patterns of Manning's roughness in the floodplain channel as well as the effects of varying roughness distribution in the main channel and floodplains. Investigators also made a number of recommendations regarding the equations that should be used to quantify the variation of the overall Manning's n value for a channel section. Suggestions were made as to the specific use of these equations, including the number of subareas within the channel to be considered, the type of division lines between the subareas, and the ranges of applicability of the equations.U.S. Department of the InteriorU.S. Geological SurveyOpe

Chronic Mitral Valve Insufficiency in Dogs: Recent Advances in Diagnosis and Treatment

Chronic mitral valvular insufficiency (CMVI) is the most common acquired heart disease in dogs and is characterized by degenerative valvular changes causing progressive thickening of mitral leaflets and incomplete closure of mitral valve. As the disease progresses, it causes congestive heart failure (CHF) and pulmonary edema if the LA dilation cannot accommodate the volume overload by mitral regurgitation. Therefore, it is the most common cause of cardiac mortality in dogs. This chapter discusses general features of CMVI in dogs focusing on recent advances in diagnosis and treatment

Perceptions of Mainland Chinese Students Toward Obtaining Higher Education in the United States

Since 1978, when the first group of 50 mainland Chinese students came to the United States for education, increasing numbers of mainland Chinese students have come to the United States to get a degree (Lampton, Madancy & Williams, 1986). In 2009, China surpassed India, becoming the largest source country of international students in the United States, and since then, China has the most international students seeking education in the United States (Open Doors Data, 2015). The purpose of this Q methodology study is to explore personal perspectives of mainland Chinese students on the value of getting a degree in the United States. Data analysis grouped similar viewpoints. Based on data from ten mainland Chinese students, we categorized three different groups of mainland Chinese students: job and education group, education group, and migration group

Flavor Changing Effects in Family Nonuniversal Z' Models

Flavor-changing and CP-violating interactions of Z' to fermions are generally present in models with extra U(1) gauge symmetry that are string-inspired or related to broken gauged family symmetry. We study the consequences of such couplings in fermion electric dipole moments, muon g-2, and K and B meson mixings. From experimental limits or measured values, we constrain the off-diagonal Z' couplings to fermions. Some of these constraints are comparable or stronger than the existing constraints obtained from other observables.Comment: 17 pages, 2 figure

Protein Adducts of Iso[4]levuglandin E2, a Product of the Isoprostane Pathway, in Oxidized Low Density Lipoprotein

Levuglandin (LG) E2, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H2, avidly binds to proteins. That LGE2-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE2-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now iso[4]LGE2-protein epitopes produced by radical-induced oxidation of arachidonic acid in the presence of protein were detected with an enzyme-linked immunosorbent assay. Iso[4]LGE2-protein epitopes are also generated during free radical-induced oxidation of LDL. All of the LGE2isomers generated upon oxidation of LDL are efficiently sequestered by covalent adduction with LDL-based amino groups. The potent electrophilic reactivity of iso-LGs can be anticipated to have biological consequences beyond their obvious potential as markers for specific arachidonate-derived protein modifications that may be of value for the quantitative assessment of oxidative injury

Micro-Raman Imaging of Isomeric Segregation in Small-Molecule Organic Semiconductors

Charge transport in organic semiconductors is highly sensitive to film heterogeneity and intermolecular interactions, but probing these properties on the length scales of disorder is often difficult. Here we use micro-Raman spectroscopy to assign vibrational modes of isomerically pure syn and anti 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT) by comparing to density functional theory calculations. With polarization-dependent measurements, we determine the orientation of crystallites in pure isomers. In mixed-isomer samples, we observe narrow linewidths and superposition spectra, indicating coexistence of isomerically pure sub-domains on length scales smaller than the probe area. Using the ring breathing modes close to 1300 cm−1 as indicators of the pure isomer crystalline sub-domains, we image their spatial distribution with 200-nm resolution. These results demonstrate the power of micro-Raman spectroscopy for investigating spatial heterogeneities and clarifying the origin of the reduced charge carrier mobility displayed in mixed-isomer diF-TES ADT

An assessment of pulse transit time for detecting heavy blood loss during surgical operation

Copyright @ Wang et al.; Licensee Bentham Open. This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.The main contribution of this paper is the use of non-invasive measurements such as electrocardiogram (ECG) and photoplethysmographic (PPG) pulse oximetry waveforms to develop a new physiological signal analysis technique for detecting blood loss during surgical operation. Urological surgery cases were considered as the control group due to its generality, and cardiac surgery as experimental group since it involves blood loss and water supply. Results show that the control group has the tendency of a reduction of the pulse transient time (PTT), and this indicates an increment in the blood flow velocity changes from slow to fast. While for the experimental group, the PTT indicates high values during blood loss, and low values during water supply. Statistical analysis shows considerable differences (i.e., P <0.05) between both groups leading to the conclusion that PTT could be a good indicator for monitoring patients' blood loss during a surgical operation.The National Science Council (NSC) of Taiwan and the Centre for Dynamical Biomarkers and Translational Medicine, National Central University, Taiwan

Compact Micromachined Infrared Bandpass Filters for Planetary Spectroscopy

The future needs of space based observational planetary and astronomy missions include low mass and small volume radiometric instruments that can operate in high radiation and low temperature environments. Here we focus on a central spectroscopic component, the bandpass filter. We model the bandpass response of the filters to target the wavelength of the resonance peaks at 20, 40, and 60 micrometers and report good agreement between the modeled and measured response. We present a technique of using common micromachining processes for semiconductor fabrication to make compact, free standing resonant metal mesh filter arrays with silicon support frames. The process can accommodate multiple detector array architectures and the silicon frame provides lightweight mechanical support with low form factor. We also present a conceptual hybridization of the filters with a detector array