Optimising the assessment of cerebral autoregulation from black box models

Cerebral autoregulation (CA) mechanisms maintain blood flow approximately stable despite changes in arterial blood pressure. Mathematical models that characterise this system have been used extensively in the quantitative assessment of function/impairment of CA. Using spontaneous fluctuations in arterial blood pressure (ABP) as input and cerebral blood flow velocity (CBFV) as output, the autoregulatory mechanism can be modelled using linear and non-linear approaches, from which indexes can be extracted to provide an overall assessment of CA. Previous studies have considered a single – or at most a couple of measures, making it difficult to compare the performance of different CA parameters. We compare the performance of established autoregulatory parameters and propose novel measures. The key objective is to identify which model and index can best distinguish between normal and impaired CA. To this end 26 recordings of ABP and CBFV from normocapnia and hypercapnia (which temporarily impairs CA) in 13 healthy adults were analysed. In the absence of a ‘gold’ standard for the study of dynamic CA, lower inter- and intra-subject variability of the parameters in relation to the difference between normo- and hypercapnia were considered as criteria for identifying improved measures of CA. Significantly improved performance compared to some conventional approaches was achieved, with the simplest method emerging as probably the most promising for future studies

Modified conjugated gradient method for diagonalising large matrices

We present an iterative method to diagonalise large matrices. The basic idea is the same as the conjugated gradient (CG) method, i.e, minimizing the Rayleigh quotient via its gradient and avoiding reintroduce errors to the directions of previous gradients. Each iteration step is to find lowest eigenvector of the matrix in a subspace spanned by the current trial vector and the corresponding gradient of the Rayleigh quotient, as well as some previous trial vectors. The gradient, together with the previous trail vectors, play a similar role of the conjugated gradient of the original CG algorithm. Our numeric tests indicate that this method converges significantly faster than the original CG method. And the computational cost of one iteration step is about the same as the original CG method. It is suitably for first principle calculations.Comment: 6 Pages, 2EPS figures. (To appear in Phys. Rev. E

Application of an adaptive neural fuzzy inference system to thermal comfort and group technology problems

AbstractThe Adaptive Neural Fuzzy Inference System (ANFIS) is used to design two vague systems, namely thermal comfort and group technologies in production and operations management. Results show that both systems can be modeled successfully by the combined use of a fuzzy approach and neural network learning

How do human resource management practices affect employee well-being? A moderated mediation model

Purpose – The study examines how human resource management practices (HRMPs) – including ability practice, motivation practice, and opportunity practice – affect employee well-being (EWB) – including life well-being, job well-being, and psychological well-being – in the Chinese cultural context. Design/methodology/approach – A sample of 529 employees from various industries in China participated in the survey for this study. Data were analyzed using structural equation modeling. Findings – The findings indicate that HRMPs have a significant positive effect on EWB. Specifically, practices based on ability, motivation, and opportunity have a significant positive effect on job well-being, life well-being, and psychological well-being respectively. Integrity leadership moderates the impact of HRMPs on EWB. Organizational justice has a partial mediating effect on the relationship between HRMPs and EWB. Integrity leadership moderates the mediation effect of organizational justice in the relationship between HRMPs and EWB. Practical implications –Human resource policies and practices need to create a fair organizational atmosphere, and managers implementing them must have integrity leadership. When selecting and promoting managers, organizations should not only pay attention to a candidate’s ability, but also his or her integrity. Originality/value – This study uncovers how the important roles of organizational justice and integrity leadership act on the relationship between HRMPs and EWB, thus advancing our understanding of how HRMPs can effectively increase EWB

Robust Visual Tracking Based on L1 Expanded Template

Most video tracking algorithms including L1 tracker often fail to track correctly under adverse conditions such as object occlusion, disappearance, etc. To address this issue, we propose an improved L1 tracker algorithm called Tracker-2, based on what we call the expanded template which includes the reference template and trail template. The reference template keeps the original features of the target and prevents errors from being introduced by false tracking results with the template update, which leads to the deviation of the target. The trail template records the trail tracking results to avoid massive use of trivial templates which may result in the false detection of occlusion. The experimental results on a number of standard data sets have proved that our Tracker-2 approach is able to deal with the occlusion problem effectively while maintaining the advantages of L1 tracker

New Finite Rogers-Ramanujan Identities

We present two general finite extensions for each of the two Rogers-Ramanujan identities. Of these one can be derived directly from Watson's transformation formula by specialization or through Bailey's method, the second similar formula can be proved either by using the first formula and the q-Gosper algorithm, or through the so-called Bailey lattice.Comment: 19 pages. to appear in Ramanujan

Superconductivity in the two dimensional Hubbard Model.

Quasiparticle bands of the two-dimensional Hubbard model are calculated using the Roth two-pole approximation to the one particle Green's function. Excellent agreement is obtained with recent Monte Carlo calculations, including an anomalous volume of the Fermi surface near half-filling, which can possibly be explained in terms of a breakdown of Fermi liquid theory. The calculated bands are very flat around the (pi,0) points of the Brillouin zone in agreement with photoemission measurements of cuprate superconductors. With doping there is a shift in spectral weight from the upper band to the lower band. The Roth method is extended to deal with superconductivity within a four-pole approximation allowing electron-hole mixing. It is shown that triplet p-wave pairing never occurs. Singlet d_{x^2-y^2}-wave pairing is strongly favoured and optimal doping occurs when the van Hove singularity, corresponding to the flat band part, lies at the Fermi level. Nearest neighbour antiferromagnetic correlations play an important role in flattening the bands near the Fermi level and in favouring superconductivity. However the mechanism for superconductivity is a local one, in contrast to spin fluctuation exchange models. For reasonable values of the hopping parameter the transition temperature T_c is in the range 10-100K. The optimum doping delta_c lies between 0.14 and 0.25, depending on the ratio U/t. The gap equation has a BCS-like form and (2*Delta_{max})/(kT_c) ~ 4.Comment: REVTeX, 35 pages, including 19 PostScript figures numbered 1a to 11. Uses epsf.sty (included). Everything in uuencoded gz-compressed .tar file, (self-unpacking, see header). Submitted to Phys. Rev. B (24-2-95

Effect of Chinese herbal medicines on rumen fermentation, methanogenesis and microbial flora in vitro

This study was carried out to evaluate the effects of three Chinese herbal medicines (CHMs) on rumen fermentation, methane emission and population of ruminal microbes using an in vitro gas production technique. Three healthy wethers of Dazu Black goats with similar bodyweights and permanent rumen fistulae were utilized as donors of ruminal fluid. The three botanical medicines were cablin patchouli herb (CPH), atractylodes rhizome (AR) and Amur cork tree (AC). Each CHM was added at a level of 25 g/kg to the substrate dry matter. In vitro gas production was recorded, and methane concentration was determined at 12 and 24 hours of incubation. After 24 hours, the incubation was stopped, and the inoculants were measured for pH, ammonia nitrogen and volatile fatty acids (VFAs) concentrations. Total deoxyribonucleic acid of ruminal microbes was extracted from the inocula, and populations were determined by a real-time quantitative polymerase chain reaction. Populations of total rumen methanogens, protozoa, total fungi, Ruminococcus albus, Fibrobacter succinogenes and Ruminococcus flavefaciens were expressed as a proportion of total rumen bacterial 16S ribosomal deoxyribonucleic acid. Compared to the control, CPH decreased gas production and methane production at 12 and 24 hours of incubation, and inhibited methanogens and total fungi growth. AR decreased acetate to propionate ratio, and methanogens and total fungi populations, but increased propionate molar proportion. AC decreased total VFA concentration, acetate to propionate ratio, gas production at 12 and 24 hours of incubation, methane production at 12 and 24 hours of incubation, and methanogens and total fungi growth, but increased the propionate molar proportion. In conclusion, CPH and AC both suppressed methanogenesis significantly, and the suppression was mediated primarily via the direct action against the rumen microbes involved in methane formation. AC also indirectly abates methane release by occupying the hydrogen (H2) normally utilized for methanogenesis.Keywords: In vitro gas production, methane, rumen fermentation parameter, rumen microbe

Responses of chemical composition, amino acid and fatty acid profiles of breast muscle to dietary crude fibre levels in China Micro-Ducks

The effects of dietary crude fibre (CF) levels on the chemical composition, amino acid (AA) and fatty acid (FA) profiles of breast muscle in male China Micro-ducks (21 - 56 d) were investigated in this study. The birds were randomly allocated to four treatments, of which dietary CF levels were 16.7, 42.6, 77.9 and 101.6 g/kg of dry matter (DM), respectively. No influences on the proportions of crude ash, crude protein, lysine, methionine, threonine, phenylalanine, histidine, arginine, aspartic acid, glutamic acid, glycine, alanine, serine, cysteine, tyrosine, proline, C12:0, C18:0, C18:1n9, C20:0 and C22:1n9 in muscle were observed across the treatments. Consequently, the concentrations of semi-essential AA, non-essential AA, total AA, aromatic AA and delicious AA in muscle, along with the Δ-9-desaturase (18) index, were not affected by the treatments. Significant lower concentrations of valine, leucine, isoleucine, essential AA, branched-chain AA, C16:1n7 and monounsaturated FA in muscle, along with a lower ratio of branched-chain to aromatic AA, were noted in a dietary treatment with a CF level of 16.7 g/kg DM compared to other dietary treatments. The rise of the dietary CF level significantly increased the proportions of DM, ether extract, gross energy, C18:2n6, C18:3n3, C20:4n6, unsaturated FA, total FA, polyunsaturated FA, n-3 polyunsaturated FA, n-6 polyunsaturated FA, essential FA, and the Δ-9-desaturase (16) index. Furthermore, the rise of the dietary CF level increased the ratios of unsaturated to saturated FA, polyunsaturated to saturated FA, and n-6 to n-3 polyunsaturated FA in muscle. However, it decreased the atherogenic index and the proportions of C14:0, C16:0, and saturated FA significantly. In conclusion, depending largely on dietary levels, CF profoundly and positively influenced the nutritional quality of breast muscle, especially the FA profile.Keywords: China Micro-duck, dietary fibre, fatty acid, nutritional quality of meat, fatty aci

A liquid helium target system for a measurement of parity violation in neutron spin rotation

A liquid helium target system was designed and built to perform a precision measurement of the parity-violating neutron spin rotation in helium due to the nucleon-nucleon weak interaction. The measurement employed a beam of low energy neutrons that passed through a crossed neutron polarizer--analyzer pair with the liquid helium target system located between them. Changes between the target states generated differences in the beam transmission through the polarizer--analyzer pair. The amount of parity-violating spin rotation was determined from the measured beam transmission asymmetries. The expected parity-violating spin rotation of order $10^{-6}$ rad placed severe constraints on the target design. In particular, isolation of the parity-odd component of the spin rotation from a much larger background rotation caused by magnetic fields required that a nonmagnetic cryostat and target system be supported inside the magnetic shielding, while allowing nonmagnetic motion of liquid helium between separated target chambers. This paper provides a detailed description of the design, function, and performance of the liquid helium target system.Comment: V2: 29 pages, 14 figues, submitted to Nucl. Instrum. Meth. B. Revised to address reviewer comment