On the numerical solution of a structured nonsymmetric algebraic Riccati equation

A class of nonsymmetric algebraic Riccati equation, where one of the two linear coefficients is block diagonal, is studied. These equations arise in the modeling of an adaptive MMAP[K]/PH[K]/1$MMAP\left[K\right]/PH\left[K\right]/1$ queue. Some theoretical results are proved, and two new algorithms are introduced that exploit the diagonal structure of the linear coefficient.     

Combining supervised and unsupervised learning for data clustering

Clustering aims to partition a data set into homogenous groups which gather similar objects. Object similarity, or more often object dissimilarity, is usually expressed in terms of some distance function. This approach, however, is not viable when dissimilarity is conceptual rather than metric. In this paper, we propose to extract the dissimilarity relation directly from the available data. To this aim, we train a feedforward neural network with some pairs of points with known dissimilarity. Then, we use the dissimilarity measure generated by the network to guide a new unsupervised fuzzy relational clustering algorithm. An artificial data set and a real data set are used to show how the clustering algorithm based on the neural dissimilarity outperforms some widely used (possibly partially supervised) clustering algorithms based on spatial dissimilarity.     

Multivariate statistical data analysis of cell-free protein synthesis toward monitoring and control

The optimization and control of cell free protein synthesis (CFPS) presents an ongoing challenge due to the complex synergies and nonlinearities that cannot be fully explained in first principle models. This article explores the use of multivariate statistical tools for analyzing data sets collected from the CFPS of Cereulide monoclonal antibodies. During the collection of these data sets, several of the process parameters were modified to investigate their effect on the end-point product (yield). Through the application of principal component analysis and partial least squares (PLS), important correlations in the process could be identified. For example, yield had a positive correlation with pH and NH₃ and a negative correlation with CO₂ and dissolved oxygen. It was also found that PLS was able to provide a long-term prediction of product yield. The presented work illustrates that multivariate statistical techniques provide important insights that can help support the operation and control of CFPS processes.     

Preparation of new ferroelectric glycine phosphite single crystals

An experimental procedure adopted to prepare the recent ferroelectric glycine phosphite single crystals is presented. As the crystal solubility in water depends on temperature, single crystals were grown from fine seed crystals in a saturated solution by employing the slow cooling technique. Transparent, colourless crystals with habit morphology weighing about 8 g were obtained within a month. The same procedure was used to grow single crystals with urea (UGPI). Powder X-ray diffraction studies as well as FTIR studies were carried out on both the crystals. The thermal properties of glycine phosphite (GPI) and UGPI across the ferroelectric phase transition temperature has been carried out. The results will be discussed in detail.     

Proteomic Analysis of Marinesco–Sjogren Syndrome Fibroblasts Indicates Pro-Survival Metabolic Adaptation to SIL1 Loss

Marinesco–Sjogren syndrome (MSS) is a rare multisystem pediatric disorder, caused by loss-of-function mutations in the gene encoding the endoplasmic reticulum cochaperone SIL1. SIL1 acts as a nucleotide exchange factor for BiP, which plays a central role in secretory protein folding. SIL1 mutant cells have reduced BiP-assisted protein folding, cannot fulfil their protein needs, and experience chronic activation of the unfolded protein response (UPR). Maladaptive UPR may explain the cerebellar and skeletal muscle degeneration responsible for the ataxia and muscle weakness typical of MSS. However, the cause of other more variable, clinical manifestations, such as mild to severe mental retardation, hypogonadism, short stature, and skeletal deformities, is less clear. To gain insights into the pathogenic mechanisms and/or adaptive responses to SIL1 loss, we carried out cell biological and proteomic investigations in skin fibroblasts derived from a young patient carrying the SIL1 R111X mutation. Despite fibroblasts not being overtly affected in MSS, we found morphological and biochemical changes indicative of UPR activation and altered cell metabolism. All the cell machineries involved in RNA splicing and translation were strongly downregulated, while protein degradation via lysosome-based structures was boosted, consistent with an attempt of the cell to reduce the workload of the endoplasmic reticulum and dispose of misfolded proteins. Cell metabolism was extensively affected as we observed a reduction in lipid synthesis, an increase in beta oxidation, and an enhancement of the tricarboxylic acid cycle, with upregulation of eight of its enzymes. Finally, the catabolic pathways of various amino acids, including valine, leucine, isoleucine, tryptophan, lysine, aspartate, and phenylalanine, were enhanced, while the biosynthetic pathways of arginine, serine, glycine, and cysteine were reduced. These results indicate that, in addition to UPR activation and increased protein degradation, MSS fibroblasts have profound metabolic alterations, which may help them cope with the absence of SIL1.     

Erbium(III) Triflate as an Extremely Active Acylation Catalyst

Erbium(III) triflate is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides {Ac₂O, (EtCO)₂O, [(CH₃)₃CO]₂O, Bz₂O, and (CF₃CO)₂O} without isomerisation of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity.     

Division of Rehabilitation Psychology: Roots, guiding principle, and a persistent concern.

What is now known as the Division of Rehabilitation Psychology was formally recognized as the 22nd Division of the American Psychological Association in September 1958. It took 10 years of persistent effort by its founders to bring that about. The first formal arrangement with APA took place in 1949 when "The National Council on Psychological Aspects of Physical Disability" became a special interest group. Now, on the occasion of the centennial celebration of the American Psychological Association, the Division of Rehabilitation Psychology honors more than 40 years of its commitment to the pursuit of knowledge and understanding of disability problems as applied to real-life issues. The author profiles the development and professional history of Division 22 of the American Psychological Association. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of neurokinin-1 receptor activation in subregions of the periaqueductal gray matter on conditional and unconditional fear behaviors in rats.

Central neurokinin-1 (NK-1) receptors are thought to modulate aversion, whereas the periaqueductal gray matter (PAG) is a common pathway for the integration of fear behaviors. The authors determined whether injection of an NK-1 agonist (GR73632) into subregions of the PAG would alter fear-related behaviors in rats. Behavioral inactivity was increased by GR73632 injected into the caudodorsal PAG or the dorsal raphe. Flight behavior induced by stimulation of the dorsal PAG or by a footshock was decreased after injection of GR73632 into the dorsal PAG. Rats that had 6 pairings of a tone with a footshock after injection of GR73632 into the dorsal PAG displayed more freezing behavior than controls at the beginning of the session. However, there was no change in the shock- or the tone-induced freezing because some GR73632-treated rats, but no controls, froze during the baseline period. It is concluded that NK-1 receptors in the dorsal PAG modulate the unconditional but not the mnemonic aspects of fear behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Pareto-based multi-objective evolutionary approach to the identification of Mamdani fuzzy systems

In the last years, the numerous successful applications of fuzzy rule-based systems (FRBSs) to several different domains have produced a considerable interest in methods to generate FRBSs from data. Most of the methods proposed in the literature, however, focus on performance maximization and omit to consider FRBS comprehensibility. Only recently, the problem of finding the right trade-off between performance and comprehensibility, in spite of the original nature of fuzzy logic, has arisen a growing interest in methods which take both the aspects into account. In this paper, we propose a Pareto-based multi-objective evolutionary approach to generate a set of Mamdani fuzzy systems from numerical data. We adopt a variant of the well-known (2+2) Pareto Archived Evolutionary Strategy ((2+2)PAES), which adopts the one-point crossover and two appropriately defined mutation operators. (2+2)PAES determines an approximation of the optimal Pareto front by concurrently minimizing the root mean squared error and the complexity. Complexity is measured as sum of the conditions which compose the antecedents of the rules included in the FRBS. Thus, low values of complexity correspond to Mamdani fuzzy systems characterized by a low number of rules and a low number of input variables really used in each rule. This ensures a high comprehensibility of the systems. We tested our version of (2+2)PAES on three well-known regression benchmarks, namely the Box and Jenkins Gas Furnace, the Mackey-Glass chaotic time series and Lorenz attractor time series datasets. To show the good characteristics of our approach, we compare the Pareto fronts produced by the (2+2)PAES with the ones obtained by applying a heuristic approach based on SVD-QR decomposition and four different multi-objective evolutionary algorithms.     

Measuring the Hysteresis Loop of Permanent Magnets With the Pulsed Field Magnetometer

We discuss a comprehensive approach to the characterization of permanent magnets with the pulsed field magnetometer. The approach is based on a systematic comparison of the results obtained by this method with those from the conventional closed-circuit and open-sample methods and on the assessment of the dynamic phenomena engendered by the application of the fast exciting field pulse. Such phenomena derive from the thermal fluctuation after effect and the eddy currents, whose contributions to hysteresis loop swelling are brought to light and separately evaluated. We show that the quasi-static hysteresis loop can be retrieved from the dynamically obtained one by compensating for the magnetic viscosity field, found to be proportional to the coercive field, and the eddy-current counterfield. A simple analytical formulation accounts for and predicts the effect of the counterfield.