bluuebunny/crossref_metadata_2025 huggingface dataset:
The Academic Medical Center Linear Disability Score for evaluation of physical reserve on admission to the ICU: can we query the relatives?
Authors: Hofhuis José GM , Dijkgraaf Marcel GW , Hovingh Aly , Braam Richard L , van de Braak Lisa , Spronk Peter E , Rommes Johannes H
Published: September 2011

Introduction

Evaluating the pre-morbid functional status in critically ill patients is important and frequently done using the physical component score (PCS) of the Short Form 36, although this approach has its limitations. The Academic Medical Center Linear Disability Score (ALDS) is a recently developed generic item bank used to measure the disability status of patients with a broad range of diseases. We aimed to study whether proxy scoring with the ALDS could be used to assess the patients' functional status on admission for cardiac care unit (CCU) or ICU patients and how the ALDS relates to the PCS using the Short Form 12 (SF-12).

Methods

Patients and proxies completed the ALDS and SF-12 score in the first 72 hours following ICU scheduled surgery (n = 14), ICU emergency admission (n = 56) and CCU emergency admission (n = 70).

Results

In all patients (n = 140) a significant intra-class correlation was found for the ALDS (0.857), the PCS (0.798) and the mental component score (0.679) between patients and their proxy. In both scheduled and emergency admissions, a significant correlation was found between patients and their proxy for the ALDS, although the lowest correlation was found for the ICU scheduled admissions (0.755) compared with the ICU emergency admissions (0.889). In CCU patients, the highest significant correlation between patients and proxies was found for the ALDS (0.855), for the PCS (0.807) and for the mental component score (0.740).

Conclusions

Relatives in close contact with critically ill patients can adequately reflect the patient's level of disability on ICU and CCU admission when using the ALDS item bank, which performed at least as well as the PCS. The ALDS could therefore be a useful alternative for the PCS of the SF-12.
Endogenous ACTH Concentration-Cortisol Secretion Dose Analysis Unmasks Decreased ACTH Potency in Cushing's Disease with Restoration after Successful Pituitary Adenomectomy
Authors: Roelfsema Ferdinand , Keenan Daniel M. , Veldhuis Johannes D.
Published: September 2011

Background:

The relationship between circulating ACTH levels and cortisol secretion in Cushing's disease is not precisely known.

Hypothesis:

Chronic ACTH hyperstimulation leads to decreased adrenal potency and is restored after normalization of ACTH secretion.

Subjects:

Subjects included 20 patients with Cushing's disease, eight patients in long-term remission, and 36 healthy controls.

Outcomes:

ACTH and cortisol secretion rates and analytical dose-response estimates of endogenous ACTH efficacy (maximal cortisol secretion), dynamic ACTH potency, and adrenal sensitivity (slope term) from 24-h ACTH-cortisol profiles were evaluated.

Results:

Both basal and pulsatile secretion of ACTH and cortisol were increased in patients with active disease but normal in cured patients. ACTH, but not cortisol pulse frequency, was amplified in patients and restored after successful surgical treatment. ACTH EC50, an inverse measure of potency, was higher during pulse onset in Cushing's disease (59 ± 7.4 ng/liter) than in controls (20 ± 3.7 ng/liter) (P < 0.0001) and remitted patients after surgery [15 ± 3.2 ng/liter, P value not significant (NS) vs. controls] and during pulse recovery phases [128 ± 18 (P <0.0001), 70 ± 8.4, and 67 ± 17 ng/liter (NS vs. controls), respectively]. Efficacy was increased in active disease and normalized after surgical treatment [patients, 38 ± 8.3 nmol/liter · min, vs. controls, 21 ± 2.3 nmol/liter · min (P <0.0001), and cured patients, 15 ± 3.2 nmol/liter · min (NS vs. controls)]. Sensitivity to endogenous ACTH did not differ among the three groups.

Conclusion:

The adrenal gland in Cushing's disease exhibits decreased responsiveness to submaximal ACTH drive and amplified efficacy, with unchanged sensitivity. These target-gland abnormalities are reversible in long-term remission after pituitary surgery.
Attention
Authors: Hertz Neil
Published: September 2011

Some notes on Eve Kosofsky Sedgwick's relation to James Merrill's poetry, “paying particular attention” to the tilt of her head and the beauty and power of her own poetry.
The Straightest Story Ever Told
Authors: Rambuss Richard
Published: September 2011

A revisionary understanding of the Passion of Christ lies at the crux of the spiritual cultural work that Dan Brown's novel The Da Vinci Code (2003) undertakes no less so than in Mel Gibson's film The Passion of the Christ (2004). Both works, each highly didactic in its own way, look to make a popular intervention into contemporary spirituality, as well as, by implication, notions of the family, marriage, and sexuality. But whereas in Gibson's film the Passion is all divine death drive—all thanatos—Brown's novel reconceives Jesus's Passion in terms of eros, though on the most heteroaggrandizing scale conceivable. Each work thus contrives its own ways to diminish, even to oust, elements of the Jesus story that could be seen to challenge sexual orthodoxies and normative familial arrangements. In its treatment of these two recent popular religious blockbusters, this essay extends across queer devotional terrain what Stephen Prothero has lately put forth as the “quest for the cultural Jesus.” It is especially concerned with what has been made of the special relation to Jesus of Mary Magdalene and John the Beloved, the two most alluring of his biblical disciples.
A Girl's Journey into the Well of Forbidden Knowledge
Authors: Cvetkovich Ann , Mitchell Allyson
Published: September 2011

The GLQ Gallery features Allyson Mitchell's 2010 installation for the Art Gallery of Ontario in Toronto, A Girl's Journey into the Well of Forbidden Knowledge. In a plus-sized version of a sculpture gallery, two large ladies, in luminescent gold and silver, face two walls of books, attached to each other and to a giant crochet brain overhead by a crochet rope that links their crotches to the brain. Mitchell recreated a version of the Lesbian Herstory Archives reading room in Brooklyn by covering the walls of the gallery with trompe l'oeil wallpaper made from drawings of the books on the shelves. In addition to photographs of the installation, the GLQ Gallery features examples of Mitchell's original drawings.

In a brief commentary on the installation, Ann Cvetkovich discusses how Mitchell brings lesbian feminist history and culture to a larger public and creates an “archive of feelings” through the affective labor of redrawing the Lesbian Herstory Archives shelves. The Gallery also features Mitchell's Deep Lez I statement, a manifesto that calls for a return to lesbian feminist culture as a resource for contemporary queer cultures.
Outside the Hollywood Canon
Authors: Pepe Kristin (KP)
Published: September 2011

By examining restoration projects completed by the Outfest Legacy Project for LGBT Film Preservation—a collaboration between Outfest and the UCLA Film & Television Archive—this essay articulates the unique challenges that the preservation and conservation of lesbian moving images have historically posed for traditional archives.
Non-periodic Space Structures
Authors: Lalvani Haresh
Published: September 2011

An interesting class of two- and three-dimensional space structures can be derived from projections of higher-dimensional structures. Regular polygons and regular-faced polyhedra provide the geometry of families of n-stars from which two- and three-dimensional projections of n-dimensional grids can be derived. These projections are rhombic space grids composed of all-space filling rhombi and rhombohedra with edges parallel to n directions. An infinite class of single-, double- and multi-layered grids can be derived-from n-sided polygons and prisms, and a finite class of multi-directional grids from the polyhedral symmetry groups. The grids can be periodic, centrally symmetric or non-periodic, and act as skeletons to generate corresponding classes of space-filling, packings and labyrinths.
Member Ductility and Design Detail of Some Welded Joints
Authors: Schmidt L. C. , Morgan P. R.
Published: September 2011

The behaviour of tubular steel members and their connections are studied under ultimate tensile load conditions. Three end connection details are considered. These are practical connections, but one has a deliberately introduced defect of welding fabrication detail. Two types of steel are used: one is a conventional semi-killed mild steel, while the other is a rimmed steel that has been cold formed to produce an enhanced yield stress. The ratio of ultimate stress to yield stress (strain hardening ratio) is widely different for the two steels. The tests highlight the reduction in ultimate-load capacity and the severely reduced ductility that follows when defects of fabrication and low strain hardening ratio steels occur together.
Geometrically Nonlinear Analysis in the Vicinity of Critical Points by the Generalized Inverse
Authors: Hangai Yasuhiko , Lin Xiao-Guang
Published: September 2011

In the geometrically nonlinear analysis for equilibrium paths, the determinant of the tangent stiffness matrix at the critical point becomes zero so that a numerically unstable situation appears in the vicinity of critical points. To avoid such a situation, many numerical methods including the arc-length method and the perturbation method have been developed.

In this paper, an analytical method to pursue the geometrically nonlinear equilibrium paths in the vicinity of critical points such as limit point and bifurcation point is presented by using the generalized inverse. In the first part, the perturbation equations for the incremental equilibrium equations are derived. Then, critical points on the equilibrium path are classified into limit point and bifurcation point by using the existence condition of solution. In the second part, an analytical method for post-critical paths beyond critical points is presented by means of the generalized inverse. In the final part, the application of the present method to the post-buckling analysis of a shallow arch and cable domes subjected to the symmetrical loads is shown.
Computational Strategies for Tracing Post-Limit-Point Paths with Pure Iterative Methods
Authors: Papadrakakis Manolis
Published: September 2011

In this work alternative methodologies are proposed for following post-buckling paths without the need for a complete factorization of the stiffness matrix or any factorization at all. This is achieved with two different approaches. The first employs nonlinear versions of preconditioned conjugate-like methods and the so called conjugate and secant-Newton methods have been tested. The second approach is based on the classical Newton-Raphson or modified Newton-Raphson methods, while for the linearized problem in each iteration the preconditioned Lanczos method is employed. Both methodologies combine the convergence properties of Newton-like methods and the low storage requirements of pure iterative methods by varying the storage demands for the preconditioning matrix according to the available computer storage facilities.
Form Generation of Polyhedric Building Shapes
Authors: Huybers P.
Published: September 2011

The Platonic - or regular - and the Archimedean - or semi-regular - polyhedra can be considered as portions of space that are completely surrounded by one or more kinds of regular polygons. The numbers and positions in space of these polygons are strictly ruled by universal criteria. It is therefore possible to form these polyhedra by placing polygons around the centre of the coordinate system in distinct numbers, at certain distances and under certain angles in accordance with these rules. This is called here ‘rotation’ and the forelying paper describes a method where this is done for the regular and semi-regular polyhedra and for related figures that are found by derivation from these polyhedra. The figures that are rotated have not necessarily to be regular polygons, nor do have to be strictly planar. This method thus allows the rotation of arbitrary figures - also spatial ones - and the rotation procedure can even be used repeatedly, so that very complex configurations can be described.
3-D form and Force Language: Proposal for a Structural Basis
Authors: Wester Ture
Published: September 2011

The usually declared archetype for structural behaviour is the lattice (bar-and-node) structure. It is true that structural manifestations in general - with great clarity - may be reduced to the two interconnected structural nuclei, the pin-jointed bar and the hinged node. The relation to the geometrical archetypes, the five regular Platonic polyhedra, is obviously unsatisfactory, as only the three triangulated polyhedra have particular structural qualities in being kinematically stable. The two remaining, the cube and the dodecahedron, are unclear and usually considered as structurally inferior or incomplete. This “Fullerian cosmology” - as it may be called - has dominated basic structural understanding for many years. The structural dual to the lattice type, the plate structure, which fits perfectly with the geometrical plane-to-point duality, not only at the level of topology and kinematic stability, but also at the level of metric geometry, magnitude of forces and elastic properties, is rarely taken into consideration. This structural duality, which was discovered around 20 years ago, has mostly been used to describe the particular qualities of the plate structure and not for its unifying qualities with the lattice structure, creating an entirety at the archetypical level of 3-D structures. This quality forms the basis for some simple unique correlations betwen geometry and structural mechanics, but it also implies that the usual basic hierarchy of 3-D geometry has to be altered accordingly. The paper will discuss some of the possibilities of creating a Form-and-Force Language on this basis.
Computational Morphogenesis
Authors: Ohmori Hiroshi
Published: September 2011

Computational morphogenesis is the word generally used for expressing those techniques or ways of thought by which the configuration or the system of structures is generated mainly through the usage of computers, which is realized on the firm foundation of both FEM as a tool of numerical analysis and various methods based on relatively newly-developed algorithms for structural optimization. Recently, it has been gaining a considerable number of users such as structural engineers or architects for the structural design of actual buildings as well as proposals for architectural competitions. Here we present the state of the art in computational morphogenesis especially in Japan as well as the future prospects for computational morphogenesis.
Farm Wide Dynamics: The Next Critical Wind Energy Frontier
Authors: McKay Phillip , Carriveau Rupp , Ting David S-K.
Published: September 2011

The dynamic behaviour of wind turbines continues to be a major area of research in the wind power industry. Increasingly, wind turbines are grouped into large arrays that form farms capable of generating hundreds of megawatts of power. Farm wide dynamics refers to the collective behaviour of multiple wind turbines that cumulatively produces effects that cannot simply be modelled by summing the behaviours of individual machines. Many facets within this topic have been addressed singly in the literature and are widely used in industry; while others are less understood. It is here asserted that the farm wide dynamic approach is essential for the optimum design, power production, management, and profitability of a wind farm. The inter-relationships between the subcomponents of farm siting, power production, and maintenance are illustrated and discussed. A simple weighting system to assist in the prioritization of the critical dynamic elements is proposed.
Performance Evaluation of Different ANN Models for Medium Term Wind Speed Forecasting
Authors: Dhivya S. , Ulagammai M. , Devi R.P.Kumudini
Published: September 2011

Wind power generation is characterized by its variability and uncertainty in the wind speed. Thus, the integration of wind farms to utility grids has several impacts on the optimum power flow, transmission congestion, load dispatch, economic analysis, and electricity market clearing prices. Due to the irregular nature of wind power production, accurate prediction of wind speed poses a major challenge to researchers. Wind speed of a wind farm is affected by conditions of the environment in which the wind farm is built, such as temperature, humidity, dew point, atmospheric pressure and wind direction. In this paper, five ANN techniques namely FFBP, CFBP, PNN, GRNN and KNN are considered to predict the wind speed using MATLAB. The feasibility of the proposed techniques is evaluated using the performance measures such as MSE, MAPE and linear regression and it is observed that GRNN is superior amongst the other methods that are used.
Efficiency Comparison of Power Electronic Converters Used in Grid-Connected Permanent-Magnet Wind Energy Conversion System Based on Semiconductors Power Losses
Authors: Arifujjaman Md , Fellow Post Doctoral , Chang L.
Published: September 2011

An efficiency comparison of power converters is presented for a permanent magnet generator based grid-connected wind energy conversion system. The power converters examined are: the intermediate boost converter (IBC), the intermediate buck-boost converter (IBBC), the back-to-back converter (BBC) and the matrix converter (MC). The aim is to determine which power electronic converter yields the highest efficiency in terms of power losses of the semiconductor devices with the varying wind speeds. In view of this, a furled wind turbine model is developed that generates power for different wind speeds. Afterwards, a relation between the wind speed and power loss is established to evaluate the efficiency of the power electronic converters for discrete wind speeds. The power loss model presented in this paper has taken into account the conduction and switching losses of the semiconductor devices within each converter. Simulation results are presented showing the power loss characteristics with the variation in wind speeds. Finally, with regard to the global efficiency for the power electronic converters of the considered wind speed regime, the IBC is found to be the most favourable choice considering the typical wind conditions encountered by a wind energy conversion system operating at the kWatt level.
A Model to Account for the Virtual Camber Effect in the Performance Prediction of an H-Darrieus VAWT Using the Momentum Models
Authors: Bianchini Alessandro , Carnevale Ennio A. , Ferrari Lorenzo
Published: September 2011

This study reports an investigation on the influence of the virtual camber effect on the performance prediction of an H-Darrieus VAWT using a theoretical approach based on the Momentum Models.

In detail, a simplified model is proposed which highlights a limit point below which the virtual camber effect must be neglected to correctly evaluate the performance of the airfoils. This correction provides a more accurate description of the unstable region of the power curve, for which very few in-depth studies are available. An accurate description of the left side of the power curve is, however, of particular importance for a correct prediction of the self-starting capabilities of the rotor, which are presently considered as a decisive requirement for small-power machines. On this basis, the effects of the new virtual camber estimation on the transient study of an H-Darrieus rotor are also presented here. This has been carried out by means of a specifically developed numerical code.

All the theoretical conjectures and the numerical models have been validated with the experimental data of two wind-tunnel campaigns on two different models of H-Darrieus turbine.
Challenges to Phasing out Fossil Fuels as the Major Source of the World's Energy
Authors: Loáiciga Hugo A.
Published: September 2011

Energy-related data for China, India, the United States, and the world were analyzed for the period 2005–2035 to gain insight on (1) the evolution of energy intensity, (2) the pattern of carbon-dioxide equivalent (CO2) emitted per unit of GDP, (3) reductions in the carbon intensity required to achieve CO2 emissions comparable to the 1990 Kyoto Protocol's baseline year, (4) key obstacles to transitioning to a world's economy less dependent on fossil fuels. Key findings are: (1) the world's total primary energy use is expected to increase by 56% in the period 2005–2035, (2) the world's rate of GDP growth outpaces its rate of increase in energy use because of a decrease in the energy/GDP ratio, (3) the world's carbon intensity in 2035 must undergo a near 4-fold reduction to achieve emissions equal to those of 1990, (4) there are major obstacles to transitioning to a world much less reliant on fossil fuels.
Fossil Fuel Consumption, Carbon Emissions and Temperature Variation in India
Authors: Das Debabrata , Srinivasan R , Sharfuddin A.
Published: September 2011

Rise in temperature is a cause of major concern across the globe. Through this study an attempt is made to project the corresponding carbon dioxide emissions and temperature variation in India using Auto Regressive Integrated Moving Average Model on past 44 years' data for predicting the future demand of petroleum oil, coal and natural gas in India. It is anticipated that the total demand for petroleum products will double by the year 2020 growing at a rate of 3.5 percent per year. The consumption of coal has witnessed an annual growth rate of 2.6 percent and the growth of natural gas is likely to be highest among all at 5.1 percent. In total, the fossil fuel consumption seems to grow at the rate of 4 percent per annum. This may cause the CO2 level to rise to one and half times by the year 2020 in comparison to that of 2008 level thus causing an increase in the surface temperature by 0.0008 percent per annum. However, the level of carbon dioxide emission and the increase in temperature can be controlled by replacing the petroleum oil and coal consumption with natural gas.
Determinants of Consumers' Demand on Energy-Efficient Air Conditioners in Saudi Arabia
Authors: Mokheimer Esmail M. A. , Eid Ashraf
Published: September 2011

Consumer preferences detailed surveys are essential for the success of energy efficiency standards and Minimum Energy Performance Standards (MEPS) programs. This article presents the results of a survey that was designed to gather information about the main determinants of consumers demand on small villas air conditioners and their willingness to pay extra money to enjoy the low power consumption of energy efficient AC. The analysis of the surveys revealed that the advantage of low power consumption tends to be the least important factor that affects consumers demand on AC compared to other economic and technological factors. This suggests that energy sector in the Saudi Government should implement short and long terms campaigns to increase the public awareness of the advantages of using energy efficient air conditioners. The survey revealed also that most of the consumers are willing to pay up to 15% extra in the retail price to purchase a more energy efficient AC. This information is very helpful for AC manufacturers and decision makers in the energy sector in Saudi Arabia.
Long-Term Instrumental and Reconstructed Temperature Records Contradict Anthropogenic Global Warming
Authors: Lüdecke Horst-Joachim
Published: September 2011

This paper analyses the monthly instrumental temperature records from 5 stations in the northern hemisphere, each of which are reliable, local and well over 200 years in length, as well as two reconstructed long-range yearly records – from a stalagmite near Innsbruck and from tree rings in the northern hemisphere that are about 2000 years long. In the instrumental records, the steepest fall in 100-year linear regression lines happened in the 19th century and the steepest rise in the 20th century, both events being of about the same magnitude. Evaluation by fluctuation analysis (FA) and detrended fluctuation analysis (DFA) revealed that both the 19th century fall and the 20th century rise have very small natural probabilities and must therefore be trends caused by external forcings. In contrast to this, the reconstructed records show far steeper 100-year rises and falls as quite common during the last 2000 years. Consequently, their DFA evaluation revealed far greater Hurst exponents. These results contradict the hypothesis of an unusual (anthropogenic) global warming during the 20th century. The cause of the different Hurst exponents for the instrumental and the reconstructed temperature records is not known. As a speculative hypothesis, the sun's magnetic field, which is correlated with sunspot numbers, could be put forward as an explanation. The long-term low-frequency fluctuations in sunspot numbers are not detectable by FA/DFA in the monthly instrumental records, resulting in low Hurst exponents. The same does not hold true for the 2000-year-long reconstructed records, which explains both their higher Hurst exponents and the higher probabilities of strong 100-year temperature fluctuations being quite common. A long-term synthetic record that embodies the reconstructed sunspot number fluctuations includes the different Hurst exponents of both the instrumental and the reconstructed records and, therefore, corroborates the conjecture.
Physico-mechanical properties and fracture characteristics of composite lumber
Authors: Bahari Shahril , Raihan Wan Jaafar Wan
Published: September 2011

The bamboo strips and oil palm trunk veneers were laid-up together alternately using phenol formaldehyde (PF) adhesive to form composite lumber with two different types of layer orientation. The composite lumber was hot pressed at two different pressing times. Physical properties test, such as cold water and hot water delamination, as well as mechanical properties test, such as flexural and compression were conducted according to a specific standard. Results showed that longer pressing time has increased all properties, except flexural and compression. Cross orientation has increased the bonding strength behaviour between bamboo strips and oil palm trunk veneers, thus influenced the low delamination percentage and good modulus of elasticity value. It is observed that the different failure behaviour was influenced by different types of layer orientation, especially in compression and physical properties. Different pressing times had not influenced any difference of failure modes.
Nanomechanical properties of differently oriented YBCO thin films
Authors: Azoulay Jacob
Published: September 2011

The high Tc superconductors (HTS) are characterized by magneto electric anisotropy due to their pronounced material anisotropy. It is expected to observe also some mechanical anisotropy. The mechanical properties of c-axis oriented and <110>-axis oriented films are reported. The two differently orientated films comprise an ideal case for comparative studies on mechanical anisotropy. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used to study the films' surface. Nanoindentation and nanoscratch techniques were used to test the elastic behaviors and hardness of the films. Mechanical anisotropies was found, analyzed and discussed.
A new calculating method for carbonate reservoir geological reserves
Authors: Li Yanchao , Wang Lei , Meng Weilong
Published: September 2011

According to the results of FMI log interpretation and the water cut trend of low permeable carbonate reservoirs, the model of the fluid distribution in the fracture-cavity pore was derived. Based on the material balance principle, assuming the original water contribution to production as constant water influx, a new calculating method for the low permeable carbonate reservoir geological reserves was presented. This method estimated the impact of origin aquifer to the geological reserves. The calculating results of example indicate that comparing to numerical simulation, this new method is high accuracy and easy to use.
Compact Green's Function for a Generic Rijke Burner
Authors: Murray P. R. , Howe M. S.
Published: September 2011

A theoretical examination is made of the thermo-acoustic properties of a Rijke burner of large aspect ratio rectangular cross-section. Such a generic device has been proposed by Kok et al. (2009 paper presented at the 16th International Congress on Sound & Vibration) to make canonical studies of combustion instabilities. An aeroacoustic Green's function is derived which permits the sound pressure produced by arbitrary thermal and vortex sources within the burner to be calculated by convolution. The Green's function corresponds to the potential flow sound field produced by an impulsive point source; its calculation taking account of flame-holder geometry is facilitated by use of the Schwarz-Christoffel transformation. The transformation is performed numerically to accommodate complex burner geometry and validated by comparison with an alternative procedure involving the direct numerical integration of Laplace's equation.
Transient Growth and Triggering in the Horizontal Rijke Tube
Authors: Juniper Matthew P.
Published: September 2011

This theoretical paper examines a non-normal and non-linear model of a horizontal Rijke tube. Linear and non-linear optimal initial states, which maximize acoustic energy growth over a given time from a given energy, are calculated. It is found that non-linearity and non-normality both contribute to transient growth and that, for this model, linear optimal states are only a good predictor of non-linear optimal states for low initial energies. Two types of non-linear optimal initial state are found. The first has strong energy growth during the first period of the fundamental mode but loses energy thereafter. The second has weaker energy growth during the first period but retains high energy for longer. The second type causes triggering to self-sustained oscillations from lower energy than the first and has higher energy in the fundamental mode. This suggests, for instance, that low frequency noise will be more effective at causing triggering than high frequency noise.
Effects of Non-Linearity on the Flame Response and Control of Combustion Instabilities in a Matrix Burner
Authors: Bohn Dieter , Ohlendorf Nils , Willie James
Published: September 2011

This paper discusses the effect of non-linearities inside a matrix burner on the flame response and control of instabilities inside the matrix burner. In particular, the response of the flame to high inlet velocity modulation level and frequency of the forcing signal are discussed. The importance of the choice of the combustion model used in the numerical simulation of combustion instabilities is highlighted. The effect of non-linearities on the choice of the primary fuel actuator used in active control is discussed. Finally, it is shown that the occurrence of limit cycle behavior inside the combustor of the matrix burner led to hysteresis. The analysis begins with the discussion of the stability map of the matrix burner obtained from measurements.
Scale-Free Modulation of Resting-State Neuronal Oscillations Reflects Prolonged Brain Maturation in Humans
Authors: Smit Dirk J. A. , de Geus Eco J. C. , van de Nieuwenhuijzen Marieke E. , van Beijsterveldt Catharina E. M. , van Baal G. Caroline M. , Mansvelder Huibert D. , Boomsma Dorret I. , Linkenkaer-Hansen Klaus
Published: September 2011

Human neuronal circuits undergo life-long functional reorganization with profound effects on cognition and behavior. Well documented prolonged development of anatomical brain structures includes white and gray matter changes that continue into the third decade of life. We investigated resting-state EEG oscillations in 1433 subjects from 5 to 71 years. Neuronal oscillations exhibit scale-free amplitude modulation as reflected in power-law decay of autocorrelations—also known as long-range temporal correlations (LRTC)—which was assessed by detrended fluctuation analysis. We observed pronounced increases in LRTC from childhood to adolescence, during adolescence, and even into early adulthood (∼25 years of age) after which the temporal structure stabilized. A principal component analysis of the spatial distribution of LRTC revealed increasingly uniform scores across the scalp. Together, these findings indicate that the scale-free modulation of resting-state oscillations reflects brain maturation, and suggests that scaling analysis may prove useful as a biomarker of pathophysiology in neurodevelopmental disorders such as attention deficit hyperactivity disorder and schizophrenia.
Preictal and Ictal Neurovascular and Metabolic Coupling Surrounding a Seizure Focus
Authors: Zhao Mingrui , Nguyen John , Ma Hongtao , Nishimura Nozomi , Schaffer Chris B. , Schwartz Theodore H.
Published: September 2011

Epileptic events initiate a large focal increase in metabolism and cerebral blood flow (CBF) to the ictal focus. In contrast, decreases in CBF have been demonstrated surrounding the focus, the etiology of which is unknown (i.e., arising either from active shunting of blood or passive steal). The relationship between these events and neuronal activity and metabolism are also unknown. We investigated neurovascular and neurometabolic coupling in the ictal surround using optical imaging of light scattering and cerebral blood volume, autofluorescence flavoprotein imaging (AFI), direct measurements of the cortical metabolic rate of oxygen and two-photon imaging of blood vessel diameter in a rat model of ictal events elicited with focal injection of 4-aminopyridine. We discovered a novel phenomenon, in which ictal events are preceded by preictal vasoconstriction of blood vessels in the surround, occurring 1–5 s before seizure onset, which may serve to actively shunt oxygenated blood to the imminently hypermetabolic focus or may be due to small local decreases in metabolism in the surround. Early ictal hypometabolism, transient decreases in cell swelling and cerebral blood volume in the surround are consistent with early ictal surround inhibition as a precipitating event in seizure onset as well as shaping the evolving propagating ictal wavefront, although the exact mechanism of these cerebrovascular and metabolic changes is currently unknown. AFI was extremely sensitive to the ictal onset zone and may be a useful mapping technique with clinical applications.
Feedback Timing Modulates Brain Systems for Learning in Humans
Authors: Foerde Karin , Shohamy Daphna
Published: September 2011

The ability to learn from the consequences of actions—no matter when those consequences take place—is central to adaptive behavior. Despite major advances in understanding how immediate feedback drives learning, it remains unknown precisely how the brain learns from delayed feedback. Here, we present converging evidence from neuropsychology and neuroimaging for distinct roles for the striatum and the hippocampus in learning, depending on whether feedback is immediate or delayed. We show that individuals with striatal dysfunction due to Parkinson's disease are impaired at learning when feedback is immediate, but not when feedback is delayed by a few seconds. Using functional imaging (fMRI) combined with computational model-derived analyses, we further demonstrate that healthy individuals show activation in the striatum during learning from immediate feedback and activation in the hippocampus during learning from delayed feedback. Additionally, later episodic memory for delayed feedback events was enhanced, suggesting that engaging distinct neural systems during learning had consequences for the representation of what was learned. Together, these findings provide direct evidence from humans that striatal systems are necessary for learning from immediate feedback and that delaying feedback leads to a shift in learning from the striatum to the hippocampus. The results provide a link between learning impairments in Parkinson's disease and evidence from single-unit recordings demonstrating that the timing of reinforcement modulates activity of midbrain dopamine neurons. Collectively, these findings indicate that relatively small changes in the circumstances under which information is learned can shift learning from one brain system to another.
Hijacking Cortical Motor Output with Repetitive Microstimulation
Authors: Griffin Darcy M. , Hudson Heather M. , Belhaj-Saïf Abderraouf , Cheney Paul D.
Published: September 2011

High-frequency repetitive microstimulation has been widely used as a method of investigating the properties of cortical motor output. Despite its widespread use, few studies have investigated how activity evoked by high-frequency stimulation may interact with the existing activity of cortical cells resulting from natural synaptic inputs. A reasonable assumption might be that the stimulus-evoked activity sums with the existing natural activity. However, another possibility is that the stimulus-evoked firing of cortical neurons might block and replace the natural activity. We refer to this latter possibility as “neural hijacking.” Evidence from analysis of EMG activity evoked by repetitive microstimulation (200 Hz, 500 ms) of primary motor cortex in two rhesus monkeys during performance of a reach-to-grasp task strongly supports the neural hijacking hypothesis.
In the Eye of the Beholder: Perspectives on Intermarriage Conversion in Orthodox Christian Parishes in Pittsburgh, Pennsylvania
Authors: Slagle Amy
Published: September 2011

Based on ethnographic research conducted in Pittsburgh, this article examines the experiences of American-born intermarriage converts to Eastern Orthodoxy. Long characterized as a variety of Christianity fundamentally ethnic in its orientation and insular in its relationships to American religious and cultural mainstreams, Eastern Orthodoxy has attracted increasing numbers of American-born converts over the last thirty years. While the motives and perspectives of more overtly theologically driven conversions have garnered attention, intermarriage conversions are often dismissed as the natural outcomes of entering into marriage and family life. Significantly, intermarriage converts frequently stress their decisions to enter the Orthodox church as autonomously made apart from external influences.

By gauging the ways intermarriage converts are depicted in parish life as well as the motives and perspectives they themselves convey in interviews, I argue that the language and assumptions of the American spiritual marketplace profoundly influence Orthodox Christian understandings of family and religion today. Personal choice and individualism rather than the expectations of traditionally ascribed identities have come to be highly valued and valorized means of counting Orthodox identity in the United States. Yet, the prevalence of marketplace values does not diminish the emotional and social impacts of family and community for intermarriage converts. Rather, I observed a general elevation in the importance of both and a frequent substantiation of their roles as the transmitters of shared values among these individuals. Thus, this article provides a case study of how individual and familial concerns further religious choice-making.
History of atrial fibrillation
Authors: Lüderitz B.
Published: September 2011

There is hardly a symptom that has impressed patients and physicians since ancient times more than an irregular heartbeat. In most cases, atrial fibrillation is the cause of the rhythm disturbance. However, it took many centuries before we were able to clearly understand fibrillation and to counteract it efficiently. The history of arrhythmia therapy with drugs is long and fascinating. Digitalis was probably the first “antiarrhythmic”. It was discovered by Leonhart Fuchs in the 16th century and introduced in the clinical practice by William Withering from Birmingham. Today's rhythm agents are of a much later date. Quinidine, an optical isomer of quinine, became clinically available in 1918. Other antiarrhythmic drugs were only developed in the 60s and 70s of the previous century, e.g. disopyramide, beta-receptor blockers, propafenone, flecainide, amiodarone, adenosine, ibutilide, and dofetilide. Among the latest commercially available antiarrhythmic substances are dronedarone and vernakalant, which were clinically introduced in 2009 and 2010, respectively. Thanks to the further development of innovative pharmaceuticals and modern electrotherapeutic methods, it can be expected that the previously therapy-resistant cases of atrial fibrillation will be lastingly reduced.
Multidetector computed tomography and coronary risk stratification — From research to clinical practice
Authors: Gonsorcik J. , Dobrovicova Adela , Gibarti C.
Published: September 2011

Cardiovascular disease due to atherosclerosis is the foremost cause of premature mortality and of disability-adjusted life years in Europe. Risk stratification management includes variety of clinical, laboratory and special diagnostic methods with different relevance. However, because global risk scores tend to underestimate risk in most persons, atherosclerosis imaging has been introduced for the refinement of stratification. Cardiac techniques including computed tomography (CT) have evolved rapidly for the study of cardiovascular structure and function. Multidetector CT is an additional relevant potential tool for assessment of coronary artery disease in selected patients and scientific data will be continuing to expand into clinical practice. Our findings showed that utility may be helpful also in non-diabetic patients with arterial hypertension or renal insufficiency and in elderly with degenerative aortic stenosis.
Atrial fibrillation as prognostic factor of myocardial infarction and/or acute heart failure
Authors: Špinar Jindřich , Ludka O. , Sepši M. , Ajibona O. , Pařenica J. , Jarkovský J.
Published: September 2011

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation with consequence deterioration of atrial mechanical function. It has an incidence of approximately 6 million people in European Union as a result of the aging population and affects about 1 percent of patients younger than 60 years and about 8 percent of patients older than 80 years [2, 10]. AF is also the most common supraventricular arrhythmia in patients with acute myocardial infarction (MI) and/or acute heart failure (AHF), complicating its course with an incidence between 6–21% in hospitalized patients with MI although recent advances in pharmacological treatment of myocardial infarction has probably changed the impact of this arrhythmia and vice versa. These two diseases (AF + MI) are a growing health concern all over the world and when one considers the occurrence of these two diseases simultaneously, the relevance of AF in the course of MI and vice versa cannot be overemphasized in cardiovascular health care and more importantly its treatment and prevention. Aim: This article therefore aims to correlate data from controlled studies to summarize the incidence of AF in MI and vice versa and the impact of pharmacotherapy. Data from our registry Brno (3502 patients with MI and/or AHF) show that AF is not a predictor of short-term mortality in patients with myocardial infarction and/or heart failure, but is a strong predictor of long-term mortality.
Echocardiography in sports cardiology: LV remodeling in athletes' heart — Questions to be answered
Authors: Zdravkovic M. , Vujusić-Tesic B. , Krotin M. , Nedeljkovic I. , Mazic S. , Stepanovic J. , Tesic M. , Ostojic M.
Published: September 2011

An enhanced risk of undesirable events has been described in individuals who take part in mainly high intensity physical activities. Underlying cardiac disorders are the most common cause of sudden death during sports activities. Left ventricular remodeling is associated with a long-term athletic training. Echocardiography is an easy, non-invasive and efficient way to the precise distinction between these exercise-induced changes, called “physiological” hypertrophy, that revert after detraining, and those of cardiac disorders or “pathological” hypertrophy. The identification of a cardiac disease in an athlete usually leads to his disqualification in an attempt to reduce the risk. On the other hand, a false diagnosis of a cardiac disease in an athlete may also lead to disqualification, thus depriving him of the various benefits from sports participation. Pronounced left ventricular dilatation and hypertrophy should always be suspected for underlying cardiac disease. Physiological left ventricular remodeling is associated with normal systolic and diastolic left ventricle function. Both global and regional left ventricle diastolic function should be evaluated. New echocardiographic techniques (tissue Doppler imaging, strain rate) have revealed “super — diastolic” left ventricle function in athletes, adding the new quality in differential diagnosis od athlete's heart syndrome.
Possible interaction of gender and age on human swallowing behavior
Authors: Dantas Roberto Oliveira , Alves Leda Maria Tavares , Santos Carla Manfredi dos , Cassiani Rachel de Aguiar
Published: September 2011

CONTEXT: The swallowing behavior is affected by age and possibly by gender. However, the interaction of the effects of age and gender on swallowing is not completely known. OBJECTIVES: To evaluate the possibility of interaction of gender and age on human swallowing behavior. METHOD: Swallowing was evaluated in 89 healthy subjects by the water swallowing test, 43 men and 46 women aged 20-40 years (younger, n = 38), 41-60 years (middle-aged, n = 31) and 61-80 years (older, n = 20). Each subject ingested in triplicate 50 mL of water while precisely timed and the number of swallows needed to ingest all the volume was counted. RESULTS: The interval between swallows was shorter and the volume in each swallow was smaller in women compared to men. In older subjects the time to ingest the 50 mL of water was longer, the interval between swallows was longer, and swallowing flow and volume in each swallow were smaller than in younger and middle-aged subjects. The swallowing flow was lower in women compared to men in younger subjects. The volume of each swallow was smaller in women than in men in younger and middle-aged subjects. There was no difference in swallowing flow and volume between older men and older women. CONCLUSION: Age and gender influence swallowing behavior, with the effect of gender being more evident in younger subjects and the effect of age being more evident in men.
The role of hilar lymphadenectomy in patients subjected to hepatectomy due to colorectal metastasis
Authors: Viana Eduardo Freitas , Herman Paulo , Coelho Fabrício Ferreira , Taka Thomas Augusto , D'Albuquerque Luiz A. Carneiro , Cecconello Ivan
Published: September 2011

CONTEXT: Hepatectomy is the treatment of choice for colorectal liver metastases, and several studies have shown good results, with 5-year survival rates ranging from 40% to 57%. Several clinical and pathological predictive factors for survival after liver resection have been studied. Involvement of the hepatic hilum lymph nodes, the incidence of which varies from 2% to 10%, indicates a poor long-term prognosis. RESULTS: Despite variable results, some authors have reported a not-insignificant improvement in survival rate in liver-metastasis patients with hilar lymph node involvement who undergo combined liver resection and lymphadenectomy. Due to the low rates of morbidity and mortality for liver-resection surgery, several specialized centers perform liver resections combined with lymphadenectomies in selected cases. It should be noted that the therapeutic value of systemic lymphadenectomy is not yet entirely understood, and only controlled studies comparing groups with and without lymphadenectomy can fully resolve the issue. CONCLUSION: In any case, hilar lymph node dissection has been shown to be a useful tool for improving the accuracy of extra hepatic disease staging, regardless of its impact on survival.