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In this paper we survey the Tychono. property for discrete groups. General results and relations with amenability, with discrete potential theory (random walks), and with the theory of weights and of characters are discussed. We then present a characterization of Tychonoff property for virtually abelian groups, for polycyclic groups, and for linear groups. We also consider the case of metabelian groups, and several examples are given.

Low temperature steam reforming (400-550°C) for the production of hydrogen offers significant advantages compared to the conventional process. The milder operating conditions lead to lower operation costs and cost of construction materials. Additionally, no CO shift reactor is required due to favorable temperature for the WGS reaction. In this work, we report the catalytic performance of Ni and Rh catalysts supported on La2O3-ZrO2 and La2O3-CeO2-ZrO2 for their application in a multifuel membrane reformer operating at low temperature. The performance of the catalysts is assessed in different operating conditions in methane steam reforming (GHSV, temperature, H2O/CH4ratio) as well as in reforming of model biogas. Stability tests were conducted up to 90h on stream (1bar and 7bar) and the tendency toward carbon formation was investigated. All catalysts were active in the reforming reactions at 400-550°C and the catalysts supported on La2O3-CeO2-ZrO2 showed superiority in activity and stability probably due to the presence of ceria in the support which contributes to the reforming rate and the resistance to carbonaceous deposits. Ni(10)CeZrLa exhibited remarkably stable performance with minimum amount of carbon formed after 90h (ca. 0.05wt%). TPO and TPH analysis of the carbonaceous deposits showed that the dominating type of carbon is highly reactive and can be easily removed by oxidation or hydrogenation at 500°C. This fact makes the catalyst even more promising for the proposed low temperature process, since the catalyst can be hydrogenated by using part of the H2 production stream without further heating of the reactor. © 2015 Elsevier B.V..

The reaction rate of low-temperature steam reforming was studied over two Ni-based catalysts. Experimental tests were carried out for temperatures between 400 and 550 °C and pressures between 1 and 7 bar, using methane and simulated biogas (1:1 methane-carbon dioxide mixture) as carbonaceous feed. The results were analyzed with a simplified reaction rate expression. The parameters of such expression were optimized in order to provide a tool for the design of an industrial scale reactor using the catalysts considered. © 2016 Hydrogen Energy Publications LLC

Background:The tensor tympani muscle is the largest muscle within the middle ear. Its voluntary contraction is a very unusual event. Only a few papers have documented its audiometric effects.Objective:To report an unusual case of voluntary tensor tympani muscle contraction and describe its audiometric effects.Case report:A 27-year-old man, who presented complaining of voluntarily evoked bilateral tinnitus, was found to be able to voluntarily contract the tensor tympani muscle in both ears simultaneously. Audiograms were performed under conditions of rest and maximal contraction of the tensor tympani muscle. The most remarkable effects were conductive hearing loss at lower frequencies and an increase in middle-ear impedance.Conclusion:The importance of the tensor tympani muscle in middle-ear physiology remains unclear. It has been related to the attenuation of sounds produced during the mastication process. Voluntary control over the tensor tympani muscle is an extremely rare event. However, an understanding of the potential audiometric effects of its contraction could aid the diagnosis of hearing disorders.

The catalytic performance on steam reforming and carbonaceous deposits was examined over Ni/La/CeO2-ZrO2 and Rh/La/CeO2-ZrO2 catalysts, prepared via wet impregnation. The catalytic performance tests were conducted using mixtures of C2–C4 alkanes and CH4 as steam reforming feedstock for 4 h at the temperature range of 400–550 °C and for 10 h at 500 °C, with S/C = 3 and GHSV = 70,000 h−1. Analysis on the used catalysts was carried out via temperature-programmed oxidation (TPO). Both catalysts showed high activity towards the alkane feedstock achieving product distribution close to that predicted by thermodynamics with no significant deactivation during the experiments. TPO of the used catalysts after 10 h on stream showed increased carbon depositions compared to the pure methane reforming but still at very low levels, even though the concentration of the second alkane used was much higher than the real concentration in natural gas.

Two integral versions of input to state stability are considered: integral input-to-state stability (iISS) and integral input-to-integral-state stability (iIiSS). We present sufficient conditions that guarantee that if a controller achieves semiglobal practical iISS (respectively, iIiSS) of an ap- proximate discrete-time model of a nonlinear sampled-data system, then the same controller achieves semiglobal practical iISS (respectively, iIiSS) of the exact discrete-time model by reducing the sampling period. Recent results on numerical methods for systems with measurable disturbances can be used to generate approximate models that we consider. Results are presented for arbitrary dynamic controllers that can be discontinuous in general.

El estudio explora simbolizaciones afectivas que estructuran las relaciones de los estudiantes en la experiencia de practicas. Con el fin de detectar las principales representaciones de 213 estudiantes universitarios de Psicologia Clinica sobre su papel como pasantes, las actividades profesionales, las funciones que tienen que cumplir y la integracion entre la educacion universitaria y los contextos reales de trabajo, se aplico un cuestionario para el analisis de la dinamica y las expectativas generadas por la imaginacion de su futuro. A traves de tecnicas estadisticas multivariantes, analisis de correspondencia multiple (ACM) y analisis de conglomerados (AC), se identificaron cuatro grupos. Los resultados fueron los siguientes: falta de poder en general, desconfianza y desmotivacion hacia practicas (17.7%); afiliacion a organismos de alojamiento con el fin de obtener el aumento de la aceptacion y poder (33.8%); alto pragmatismo, orientacion a la tarea y el cumplimiento de lo que los cuerpos de alojamiento proponen (30.8%) y demanda de reconocimiento sin ninguna negociacion (17.7%). No se detecto ninguna relacion entre los clusteres y algunas variables ilustrativas relacionadas con el sexo y los indicadores de exito academico, los problemas y la participacion. Estas agrupaciones se conciben como dimensiones latentes que explican el 57.9% de la varianza total y se refieren a: la desconexion/implicacion hacia la experiencia de practicas; impotencia/omnipotencia sobre el uso de las competencias y la devaluacion/idealizacion del cuerpo de alojamiento en relacion con la formacion universitaria. Surgen dos cuestiones fundamentales: la brecha entre la formacion universitaria y las practicas, la segunda se ocupa de la discontinuidad entre las practicas y el mercado laboral. Se discuten algunas reflexiones e implicaciones para la practica.

A method is described for set-point tracking in nonlinear systems when pointwise-in-time input and/or state inequality constraints are to be enforced. It consists of adding to a primal compensated system a nonlinear device called command governor (CG) whose action is based on the current state, set-point, and prescribed constraints. The CG selects at any time the system input via a receding-horizon strategy from a virtual sequence amongst all possible command sequences by solving a constrained quadratic optimization problem. Provided that the initial state is admissible, the overall system is proved to fulfil the constraints and have desirable performance stability properties.

In this paper, we deal with the problem of stabilization of uncertain systems in the presence of input constraint. First algebraic conditions are derived for input-to-state stability of linear system with saturated linear feedback of low dimension. Then a recursive design procedure is derived for robust stabilization of block upper triangular nonlinear systems with feedforward structure.

The methane steam reforming (MSR) technology is the oldest and the most vital route to convert CH4 into H2. The conventional process usually operates in a high temperature range of 973-1173 K due to the highly endothermic nature of the reforming reaction. Necessity to increase the energy efficiency leads to the development of processes operating at low temperature and of highly active and coke resistant catalysts. An active catalyst which can provide high reforming reaction rates at low temperature (

In this paper we present new results on asymptotic consensus for continuous-time nonlinear time varying cooperative networks. We endow the well known assumption of integral connectivity proposed by Moreau with a remarkable additional feature of being frozen in state variables, making its direct verification more straightforward. Moreover, we give an estimate of the exponential rate of convergence towards the agreement manifold.

Objective To describe and analyze the main outcomes achieved in a series of patients with sporadic vestibular schwannoma (VS) larger than 40 mm in extrameatal diameter, defined as giant VS, submitted to microsurgery by the enlarged translabyrinthine approach with transapical extension. Study design Retrospective chart review. Setting Tertiary referral center. Patients A retrospective chart review was conducted on 2,133 patients who underwent surgery for VS from April 1987 to July 2009. One hundred ten cases of giant VS were elected for analysis. Main outcome measures Extent of removal, residual or recurrent disease, facial nerve integrity during surgery, long-term facial nerve function, and postoperative complications. Results Total removal was accomplished in 91.8% of cases. In 5 patients (4.5%), total removal was accomplished in 2 stages. Near-total removal was performed in 7 patients (6.3%). The facial nerve was anatomically preserved in 76.4% of cases. Intraoperative facial nerve reconstruction was performed in 8 cases. Facial nerve function after 1 year of follow-up was House-Brackmann grades I to III in 75% of cases. There were no deaths in this series. Neurovascular life-threatening complications occurred in 2 patients. Cerebrospinal fluid leak was present in 1.8% of cases. Conclusion Results indicate the enlarged translabyrinthine approach with transapical extension as an elective approach for removal of giant VS. The method permits achievement of a high rate of total removal with low incidence of complications.

The cytopathology of a Potato virus X (PVX) recombinant variant (encoding as fusion of an epitope of immunological interest with the N-terminus of the coat protein, PVX Sma P18DD) has been compared with that induced by the wild-type virus (PVX wt) in Nicotiana benthamiana plants. Both PVX wt and PVX Sma P18DD caused similar ultrastructural alterations, characterized by the presence of laminated inclusion components and bulk virus accumulations in mesophyll cells. However, some striking differences were observed not only in the morphology of these accumulations (typically ordered in PVX wt infection and disordered in PVX Sma P18DD infection) but also because the chimeric virus caused peculiar alterations in chloroplasts structure.

This paper is a collection of general results in geometric group theory, concerning, in particular, amenability and its relation with growth of groups, cohomology and weights.

Results for estimating the convergence rate of non-stationary distributed consensus algorithms are provided, on the basis of qualitative (mainly topological) as well as basic quantitative information (lower-bounds on the matrix entries). The results appear to be tight in a number of instances and are illustrated through simple as well as more sophisticated examples. The main idea is to follow propagation of information along certain spanning trees which arise in the communication graph.

New results on the structure of density functions for almost global stability analysis of nonlinear systems are discussed. In particular, it is shown how the smoothness constraint poses, under certain technical assumptions, a serious challenge in the construction of density functions which are almost everywhere expanding along the flow.

This paper provides a solution to the problem of controlling the orientation of a geostationary spacecraft, subject to actuator failures. The proposed scheme is based on a two levels Supervisory Switching Logic. It selects the most appropriate controller from a bank of candidate control laws, depending on the state of the actuators. In order to establish the working conditions of the satellite, techniques of fault detection and fault diagnosis are adopted.

A new input-output qualitative notion, closely related to passivity, is introduced for general nonlinear systems with inputs and outputs and its usefulness in proving convergence in positive feedback interconnections is investigated. This property, roughly speaking, plays for positive feedback the natural counter-part of what passivity is for negative feedback interconnections.

International audience; In this paper we deal with the problem of stabilization of uncertain systems in the presence of input constraint. First algebraic conditions are derived for input-to-state stability of linear system with saturated linear feedback of low dimension. Then a recursive design procedure is derived for robust stabilization of block upper triangular nonlinear systems with feedforward structure.

Two different adaptive controllers for systems with backlash acting on the input are discussed: one in continuous time and one in discrete time. Both schemes are based on a backlash inverse and a linear controller. The unknown plant parameters and the backlash width are estimated. The estimated parameters are used for pole placement design of the controller and for backlash compensation in the backlash inverse. Some analysis of the estimator convergence is done. Simulations of a second order plant show that both schemes give a nice behavior.

The pathogenetic mechanism underlying glucose intolerance in pancreatic cancer is still unclear. We studied the pattern of three glucose regulating hormones (C-peptide, glucagon and GH) in pancreatic cancer patients with (N = 34) and without (N = 8) hyperglycemia, and compared the findings made with those from subjects with other hyperglycemic conditions of well-known origin [type I diabetes mellitus (8 cases) and diabetes mellitus secondary to chronic pancreatitis (13 cases) or liver cirrhosis (4 cases)]. In hyperglycemic pancreatic cancer patients, C-peptide was absent in 26% of the cases, reduced in 24%, elevated in 29% and within the normal range in the remaining 21%. In normoglycemic pancreatic cancer this hormone was reduced in two cases (25%) and within the normal range in all the others. GH was within the normal range in all cases: glucagon was below the normal range in some hyperglycemic pancreatic cancer patients (41%) or within the normal range in all the remaining patients. No correlations were found between the three hormones when findings from subjects were considered all together. However, in pancreatic cancer C-peptide and glucagon presented consensual variations. C-peptide, glucagon and GH levels were not related to tumor volume; glucagon was found to be associated with liver metastases. C-peptide was correlated with serum ALT and ALP. We may conclude that hyperglycemia associated with pancreatic cancer may be caused by different mechanisms. In some cases a reduced secretion of both insulin and glucagon was observed, as occurs in chronic pancreatitis. In the majority of patients, beta cell function appears normal, and the hyperglycemic state may depend on an altered peripheral sensitivity to insulin due to the pancreatic pathology itself or to consensual liver involvement.

Systems with counter-clockwise input-output (I-O) dynamics were recently introduced in order to study the convergence of positive feedback loops (possibly to many different equilibrium states). The author shows how this notion can be used to perform bifurcation analysis and globally predict multistability of a closed-loop feedback interconnection just by using the knowledge of steady-state I-O responses of the systems. To illustrate the theory, this method is then applied to a recently published model of mitogen activated protein kinase (MAPK) cascade. Furthermore, some examples (mainly motivated by molecular biology) of systems that enjoy the property are presented and discussed.

Equilibrium hydration of p-methoxy-α-α-α-trifluoroacetophenone (MTFA) in water and anionic micelles of sodium dodecyl sulfate (SDS) has been followed by 19F NMR and UV spectrometry, and is strongly disfavored by the micelles. The effects can be separated into those due to the different transfer equilibria of the carbonyl and hydrate forms and to a decrease in water activity in the micelles. The transfer equilibria of the carbonyl and hydrate forms of MTFA between water and micelles have been followed by NMR spectrometry and an activity of water at the micellar surface of 0.6 has been determined. Attainment of hydration equilibrium in water, aqueous acetonitrile, and micelles has been followed by UV spectrometry and rate constants for forward and reverse reactions have been calculated. The overall equilibrium of the p-octyloxy derivative has been examined in aqueous acetonitrile and SDS micelles. The hydrophobic octyl group reduces the rate and equilibrium constants of hydration.

The aim of this study was to assess the behavior of fasting serum glucose, C-peptide levels and OGTT in pancreatic cancer follow-up. We studied 49 patients with pancreatic cancer (stage I = 8 pts; II = 16 pts; III = 12 pts; IV = 13 pts). At diagnosis 13/49 patients had fasting serum glucose levels of above 140 mg/dL. Of the remaining 36 pts, 22 underwent OGTT, which indicated diabetes mellitus in 9/22 (41%) and impaired glucose tolerance in 7/22 (32%) cases. C-peptide basal values were within the normal range (0.8-2.0 micrograms/L) in 14/49 (28%), above 2.0 micrograms/L in 6/49 (13%) and below 0.8 micrograms/L in 29/49 (59%) of the cases. No significant correlation was found between tumor stage or size and the presence of diabetes or of a reduced glucose tolerance. Twenty-four patients underwent curative resection (group 1) and 16 palliative resection, while the remaining nine did not undergo surgery (group 2). Group 1 and 2 patients had a follow-up of 2 to 40 months (mean = 14 months) and from 1 to 7.5 months (mean = 3.5 months) respectively. In group 1 patients no significant difference was found between pre- and post-operative fasting serum glucose levels. However, in 11/15 (73%) patients who underwent OGTT before and after surgery, an improvement in glucose tolerance was observed after tumor resection. In group 2 patients, a significant increase in fasting serum glucose levels was found during follow-up. In neither of the groups studied were significant variations found in C-peptide levels during the follow-up, although a slight increase was observed in patients who did not undergo surgery. In conclusion, the reduced glucose tolerance or frank diabetes mellitus, which frequently occurs during the onset of pancreatic cancer, does not seem to be related to tumor stage or size. Curative resection ameliorates glucose intolerance, while tumor persistence can enhance serum glucose levels.

Aims Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion therapy in ST-elevation myocardial infarction (STEMI). We conducted this study to evaluate the contemporary status on the use and type of reperfusion therapy in patients admitted with STEMI in the European Society of Cardiology (ESC) member countries. Methods and results A cross-sectional descriptive study based on aggregated country-level data on the use of reperfusion therapy in patients admitted with STEMI during 2010 or 2011. Thirty-seven ESC countries were able to provide data from existing national or regional registries. In countries where no such registries exist, data were based on best expert estimates. Data were collected on the use of STEMI reperfusion treatment and mortality, the numbers of cardiologists, and the availability of PPCI facilities in each country. Our survey provides a brief data summary of the degree of variation in reperfusion therapy across Europe. The number of PPCI procedures varied between countries, ranging from 23 to 884 per million inhabitants. Primary percutaneous coronary intervention and thrombolysis were the dominant reperfusion strategy in 33 and 4 countries, respectively. The mean population served by a single PPCI centre with a 24-h service 7 days a week ranged from 31 300 inhabitants per centre to 6 533 000 inhabitants per centre. Twenty-seven of the total 37 countries participated in a former survey from 2007, and major increases in PPCI utilization were observed in 13 of these countries. Conclusion Large variations in reperfusion treatment are still present across Europe. Countries in Eastern and Southern Europe reported that a substantial number of STEMI patients are not receiving any reperfusion therapy. Implementation of the best reperfusion therapy as recommended in the guidelines should be encouraged