bluuebunny/crossref_metadata_2025 huggingface dataset:
Outer Membrane Vesicles
Authors: McBroom Amanda J. , Kuehn Meta J.
Published: July 2009

Outer membrane vesicles (blebs) are produced by
Escherichia coli
,
Salmonella
, and all other gram-negative bacteria both in vitro and in vivo. Most of the research in the field has focused on the properties of vesicles derived from pathogenic bacteria and their interactions with eukaryotic cells. These data indicate that vesicles are able to contribute to pathogenesis. Thus, it appears that pathogenic gram-negative bacteria have co-opted vesicles for the dissemination of virulence determinants. However, the role of vesicle production by nonpathogenic bacteria is less obvious. This section reviews the data demonstrating the mechanistic and physiological basis of outer membrane vesicle production by bacteria. Vesiculation can be seen as a mechanism for cells to react to conditions in the surrounding environment by carrying away unnecessary components and allowing rapid modification of the outer membrane composition. In addition, vesicles can transmit biological activities distant from the originating cell. Vesicles could act to bind and deplete host immune factors at the site of infection that would otherwise attack the bacteria. Vesicles in the area surrounding the cell may also provide the cell protection inside a human or animal host. The concept of vesicles as virulence factors has received considerable attention, and they are likely to play a significant role in the pathogenesis of gram-negative bacteria. By analysis of their composition, mechanism of formation, regulation, and physiological function, progress is being made in understanding the ubiquitous nature of outer membrane vesicles produced by gram-negative bacteria.
Introduction and Perspectives
Authors: Sauer Uwe
Published: July 2009

Classically, metabolism was investigated by studying molecular characteristics of enzymes and their regulators in isolation. This reductionistic approach successfully established mechanistic relationships with the immediate interacting neighbors and allowed reconstruction of network structures. Severely underdeveloped was the ability to make precise predictions about the integrated operation of pathways and networks that emerged from the typically nonlinear and complex interactions of proteins and metabolites. The burden of metabolic engineering is a consequence of this fact—one cannot yet predict with any certainty precisely what needs to be engineered to produce more complex phenotypes. What was and still is missing are concepts, methods, and algorithms to integrate data and information into a quantitatively coherent whole, as well as theoretical concepts to reliably predict the consequence of environmental stimuli or genetic interventions. This introduction and perspective to Domain 3, Metabolism and Metabolic Fluxes, starts with a brief overview of the panoply of global measurement technologies that herald the dawning of systems biology and whose impact on metabolic research is apparent throughout the Domain 3. In the middle section, applications to
Escherichia coli
are used to illustrate general concepts and successes of computational methods that approach metabolism as a network of interacting elements, and thus have potential to fill the gap in quantitative data and information integration. The final section highlights prospective focus areas for future metabolic research, including functional genomics, eludication of evolutionary principles, and the integration of metabolism with regulatory networks.
Succinate as Donor; Fumarate as Acceptor
Authors: Tomasiak Thomas M. , Cecchini Gary , Iverson Tina M.
Published: July 2009

Succinate and fumarate are four-carbon dicarboxylates that differ in the identity of their central bond (single or double). The oxidoreduction of these small molecules plays a central role in both aerobic and anaerobic respiration. During aerobic respiration, succinate is oxidized, donating two reducing equivalents, while in anaerobic respiration, fumarate is reduced, accepting two reducing equivalents. Two related integral membrane Complex II superfamily members catalyze these reactions, succinate:ubiquinone oxidoreductase (SQR) and fumarate:menaquinol oxidoreductase (QFR). The structure, function, and regulation of these integral-membrane enzymes are summarized here. The overall architecture of these Complex II enzymes has been found to consist of four subunits: two integral membrane subunits, and a soluble domain consisting of an iron-sulfur protein subunit, and a flavoprotein subunit. This architecture provides a scaffold that houses one active site in the membrane and another in the soluble milieu, making a linear electron transfer chain that facilities shuttling of reducing equivalents between the two active sites. A combination of kinetic measurements, mutagenesis, electron paramagnetic resonance spectroscopy, UV/Vis spectroscopy, and x-ray crystallography have suggested mechanisms for succinate:fumarate interconversion, electron transfer, and quinone:quinol interconversion. Of particular interest are the structural details that control directionality and make SQR and QFR primed for preferential catalysis each in different favored directions.
EFFECTIVE ŁOJASIEWICZ INEQUALITY FOR ARITHMETICALLY DEFINED VARIETIES AND A GEOMETRIC APPLICATION TO BIHOMOGENEOUS POLYNOMIALS
Authors: TO WING-KEUNG , YEUNG SAI-KEE
Published: July 2009

We establish two versions of effective Łojasiewicz inequality for arithmetically defined affine varieties. As an application, we consider bihomogeneous polynomials on the complex Euclidean space which are positive along the affine cone of an arithmetically defined projective variety, and we obtain effective estimates on certain modifications needed to turn them into sums of squares of pointwise norms of homogeneous polynomials. The latter can be interpreted as an effective result on isometric embeddings for the associated indefinite Hermitian holomorphic line bundles.
THE MODULI STACK OF RANK-TWO GIESEKER BUNDLES WITH FIXED DETERMINANT ON A NODAL CURVE II
Authors: ABE TAKESHI
Published: July 2009

We introduce a new definition of rank 2 Gieseker-bundles with fixed determinant on a nodal curve, and show that their moduli stack is normal crossing.
MILNOR K-GROUP ATTACHED TO A TORUS AND BIRCH–TATE CONJECTURE
Authors: YAMAZAKI TAKAO
Published: July 2009

We formulate (and prove under a certain assumption) a conjecture relating the order of Somekawa's Milnor K-group attached to a torus T and the value of the Artin L-function attached to the cocharacter group of T (regarded as an Artin representation) at s = -1. The case T = 𝔾m reduces to the classical Birch–Tate conjecture.
BEAM SEARCH HEURISTICS FOR THE SINGLE MACHINE SCHEDULING PROBLEM WITH LINEAR EARLINESS AND QUADRATIC TARDINESS COSTS
Authors: VALENTE JORGE M. S.
Published: July 2009

In this paper, we consider the single machine scheduling problem with linear earliness and quadratic tardiness costs, and no machine idle time. We present heuristic algorithms based on the beam search technique. These algorithms include classic beam search procedures, as well as the filtered and recovering variants. Several dispatching rules are considered as evaluation functions, to analyze the effect of different rules on the effectiveness of the beam search algorithms.

The computational results show that using better rules improves the performance of the beam search heuristics. The detailed, filtered beam search (FBS) and recovering beam search (RBS) procedures outperform the best existing heuristic. The best results are given by the recovering and detailed variants, which provide objective function values that are quite close to the optimum. For small to medium size instances, either of these procedures can be used. For larger instances, the detailed beam search (DBS) algorithm requires excessive computation times, and the RBS procedure then becomes the heuristic of choice.
STABILITY OF THE MULTI-TYPE REENTRANT LINES WITH TYPE PRIORITY SERVICE DISCIPLINE
Authors: YANG JIANKUI
Published: July 2009

This paper studies the fluid model of a special kind of multi-type queueing network with type priority. The fluid of the same type in the same station is operated under last buffer first served (LBFS) policy. The stability of this kind of fluid model is proved via the Lyapunov function.
A WAVELENGTH CONVERSION BASED ON CROSS-GAIN MODULATION OF A SEMICONDUCTOR OPTICAL AMPLIFIER FIBER RING LOOP
Authors: TANG YONGAN , SIAHMAKOUN AZAD , SERGIO GRANIERI , TEFERRA SEIFU , VLAHOVIC BRANISLAV , CHENG CHENG
Published: July 2009

We investigate the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA) fiber ring loop theoretically and experimentally. Based on the XGM, a wavelength conversion is designed. We experimentally carry out an SOA wavelength conversion, which converts a 20 MHz sinusoidal modulated input optical signal at a wavelength of 1317 nm to an output optical signal at a wavelength of 1314.3 nm. In this type of wavelength conversion, a tunable optical filter is utilized to select the target wavelength of the output signal from the fiber ring loop, and this target wavelength signal is accumulated and amplified as the resonance of the fiber ring loop. The introduction of the tunable optical filter into the fiber ring loop system makes it very easy to obtain any desired target wavelength from this XGM wavelength conversion system; this remarkable property means that the SOA wavelength conversions have broader applications in optical networking and beyond. Higher frequency modulation XGM wavelength conversion may be obtained by scaling down the length of the fiber ring loop.
INSIGHT INTO THE GROWTH MECHANISM OF WS2 NANOTUBES IN THE SCALED-UP FLUIDIZED-BED REACTOR
Authors: ZAK A. , SALLACAN-ECKER L. , MARGOLIN A. , GENUT M. , TENNE R.
Published: July 2009

The growth mechanism of WS2 nanotubes in the large-scale fluidized-bed reactor is studied in greater detail. This study and careful parameterization of the conditions within the reactor lead to the synthesis of large amounts (50–100 g/batch) of pure nanotubes, which appear as a fluffy powder, and (400–500 g/batch) of nanotubes/nanoplatelets mixture (50:50), where nanotubes usually coming in bundles. The two products are obtained simultaneously in the same reaction but are collected in different zones of the reactor, in a reproducible fashion. The characterization of the nanotubes, which grow catalyst-free, by a number of analytical techniques is reported. The majority of the nanotubes range from 10 to 50 micron in length and 20–180 nm in diameter. The nanotubes reveal highly crystalline order, suggesting very good mechanical behavior with numerous applications.
Proglacial, periglacial or paraglacial?
Authors: Slaymaker Olav
Published: July 2009

The terms proglacial and periglacial are well-understood descriptors of contemporary and past environments, but the paraglacial concept is more controversial and has prompted vigorous debate. Definitions are reviewed and the paraglacial concept is considered critically. It is argued that the term ‘paraglacial’ defined as ‘non-glacial processes conditioned by glaciation’ describes landscapes that are adjusted neither to Last Glacial Maximum nor to contemporary geomorphic processes. Where a landscape is paraglacial it can be characterized in terms of rate of change and trajectory of that change. It cannot be defined in relation to glaciers (as in proglacial) or by cold-climate processes (as in periglacial). Almost all paraglacial landforms and all paraglacial landscapes are transient and transitional. An interesting challenge of paraglacial landscapes is then to determine their rates of change; how far they have advanced along the trajectory from glacial to non-glacial; and how to recognize empirically the temporal and spatial relationships between proglacial, periglacial, paraglacial and fluvial landscapes. Implications of this approach to paraglacial landscapes are discussed in relation to historical and dynamic geomorphology.
On the interpretation of discrete debris accumulations associated with glaciers with special reference to the British Isles
Authors: Whalley W. Brian
Published: July 2009

A selection of glacial deposits with distinct morphological or stratigraphic forms associated with glaciers is considered with respect to climatic signals and debris inputs at the time of formation. The relationships are by no means simple and consideration is given, in general terms, to the range of conditions that might apply to a range of depositional features now found ‘relict’ in the British Isles. These factors are spatial (including continentality) and altitudinal, as well as climate and climatic variability. Examples, mainly from present-day marginally glacierized environments, are given to illustrate the complexity of these interrelationships. Features included are: plateau glaciers and their outlets, where moraines of the outlet glaciers may not be representative of the overall behaviour; plateau glaciers and remnant blockfields related to time of formation; the formation of moraines and rock glaciers; and protalus ramparts and protalus lobes as functions of ice and debris input, as well as thermal regime. It is suggested that the relative amounts of ice and rock debris are important in the formation of certain features. Understanding these relationships is an on-going process and is required for effectively mapping an interpretation of past local- and medium-scale environmental conditions.
Is There Glucose Production Outside of the Liver and Kidney?
Authors: Previs Stephen F. , Brunengraber Daniel Z. , Brunengraber Henri
Published: July 2009

This review analyzes the evidence presented to support the role of organs other than the liver and kidney to release substantial amounts of glucose into the mammalian blood circulation. The evidence includes (a) the identification of gluconeogenic enzyme activities in various organs, especially the small intestine, (b) levels of mRNA for the same enzymes, and (c) measurements of gluconeogenic flux in the small intestine. The latter would be the definite proof of extrahepatic, extrarenal glucose production. We critically evaluate the radioactive and stable isotopic techniques used to measure intestinal gluconeogenesis. We also simulate the impact of unavoidable measurement errors on apparent rates of intestinal gluconeogenesis. We conclude that there is so far no credible evidence to support the concept that glucose can be produced by the intestine or by muscle.
Development of a Dynamic Virtual Reality Model of the Inner Ear Sensory System as a Learning and Demonstrating Tool
Authors: Selva P. , Morlier J. , Gourinat Y.
Published: July 2009

In order to keep track of the position and motion of our body in space, nature has given us a fascinating and very ingenious organ, the inner ear. Each inner ear includes five biological sensors—three angular and two linear accelerometers—which provide the body with the ability to sense angular and linear motion of the head with respect to inertial space. The aim of this paper is to present a dynamic virtual reality model of these sensors. This model, implemented in MATLAB/Simulink, simulates the rotary chair testing which is one of the tests carried out during a diagnosis of the vestibular system. High-quality 3D animations linked to the Simulink model are created using the export of CAD models into Virtual Reality Modeling Language (VRML) files. This virtual environment shows not only the test but also the state of each sensor (excited or inhibited) in real time. Virtual reality is used as a tool of integrated learning of the dynamic behavior of the inner ear using ergonomic paradigm of user interactivity (zoom, rotation, mouse interaction, etc.). It can be used as a learning and demonstrating tool either in the medicine field—to understand the behavior of the sensors during any kind of motion—or in the aeronautical field to relate the inner ear functioning to some sensory illusions.
Nevus-Like Appearance of Primary Malignant Melanoma of the Esophagus
Authors: Kang Min-Jung , Yi Sun Young
Published: July 2009

The primary malignant melanoma of the esophagus (PMME) is a rare malignant disease, accounting for only 0.1–0.2% of all esophageal neoplasms, and the majority of the patients are diagnosed at advanced stages with poor prognosis. We present here a case of 56-year-old woman with epigastric pain and her endoscopic finding revealed several flat and black pigmented mucosal lesions within the distal portion of the esophagus which looked like flat nevus. The histopathology and immunohistochemical profile of the tissue specimens were diagnostic of malignant melanoma.
An Evolutionary Method for Combining Different Feature Selection Criteria in Microarray Data Classification
Authors: Dessì Nicoletta , Pes Barbara
Published: July 2009

The classification of cancers from gene expression profiles is a challenging research area in bioinformatics since the high dimensionality of microarray data results in irrelevant and redundant information that affects the performance of classification. This paper proposes using an evolutionary algorithm to select relevant gene subsets in order to further use them for the classification task. This is achieved by combining valuable results from different feature ranking methods into feature pools whose dimensionality is reduced by a wrapper approach involving a genetic algorithm and SVM classifier. Specifically, the GA explores the space defined by each feature pool looking for solutions that balance the size of the feature subsets and their classification accuracy. Experiments demonstrate that the proposed method provide good results in comparison to different state of art methods for the classification of microarray data.
Functional Expression of a DNA‐Topoisomerase IB from Cryptosporidium parvum
Authors: Ordóñez César , Alfonso Javier , Balaña-Fouce Rafael , Ordóñez David
Published: July 2009

Cryptosporidium parvum, one of the most important causative organisms of human diarrheas during childhood, contains a monomeric DNA‐topoisomerase IB (CpTopIB) in chromosome 7. Heterologous expression of CpTopIB gene in a budding yeast strain lacking this activity proves that the cryptosporidial enzyme is functional in vivo. The enzymatic activity is comprised in a single polypeptide, which contains all the structural features defining a fully active TopIB. Relaxation activity of the yeast extracts was detected only when CpTopIB ORF was expressed in a yeast expression system showing time and protein dependence under steady state kinetic conditions. The susceptibility of CpTopIB‐transformed yeast to the irreversible inhibitor camptothecin and its water‐soluble derivatives (topotecan and SN‐38) was assessed.
A Note on Topological Properties of Non‐Hausdorff Manifolds
Authors: Kent Steven L. , Mimna Roy A. , Tartir Jamal K.
Published: July 2009

The notion of compatible apparition
points is introduced for non‐Hausdorff manifolds, and
properties of these points are studied. It is well known that the Hausdorff property is independent of the other conditions given in the standard definition of a topological manifold. In much of literature, a
topological manifold of dimension n is a Hausdorff topological space which has a countable base of open sets and is locally Euclidean of dimension n. We begin with the definition of a non‐Hausdorff topological manifold.
Time Ordering Effects on Hydrogen Zeeman-Stark Line Profiles in Low-Density Magnetized Plasmas
Authors: Rosato J. , Boland D. , Difallah M. , Marandet Y. , Stamm R.
Published: July 2009

Stark broadening of hydrogen lines is investigated in low-density magnetized plasmas, at typical conditions of magnetic fusion experiments. The role of time ordering is assessed numerically, by using a simulation code accounting for the evolution of the microscopic electric field generated by the charged particles moving at the vicinity of the atom. The Zeeman effect due to the magnetic field is also retained. Lyman lines with a low principal quantum number n are first investigated, for an application to opacity calculations; next Balmer lines with successively low and high principal quantum numbers are considered for diagnostic purposes. It is shown that neglecting time ordering results in a dramatic underestimation of the Stark effect on the low-n lines. Another conclusion is that time ordering becomes negligible only when ion dynamics effects vanish, as shown in the case of high-n lines.
Prediction of All-Cause Mortality From Global Longitudinal Speckle Strain
Authors: Stanton Tony , Leano Rodel , Marwick Thomas H.
Published: July 2009

Background—

Although global left ventricular systolic function is an important determinant of mortality, standard measures such as ejection fraction (EF) and wall motion score index (WMSI) have important technical limitations. The aim of this study was to compare global longitudinal speckle strain (GLS), an automated technique for measurement of long-axis function, with EF and WMSI for the prediction of mortality.

Methods and Results—

Of 546 consecutive individuals undergoing echocardiography for assessment of resting left ventricular function, 91 died over a period of 5.2�1.5 years. In addition to Simpson biplane EF, WMSI was determined by 2 experienced readers and GLS was calculated from 3 standard apical views using 2D speckle tracking. The incremental value of EF, WMSI, and GLS to significant clinical variables was assessed in nested Cox models. Clinical factors associated with outcome (model χ
2
=20.2) were age (hazard ratio [HR], 1.46;
P
<0.01), diabetes (HR, 1.88;
P
=0.01), and hypertension (HR, 1.59;
P
<0.05). Although addition of EF (HR, 1.23;
P
=0.03) or WMSI (HR, 1.28;
P
<0.01) added to the predictive power of clinical variables, the addition of GLS (HR, 1.45;
P
<0.001) caused the greatest increment in model power (χ
2
=34.9,
P
<0.001). GLS also provided incremental value in subgroups with EF >35% and those with and without wall motion abnormalities. A GLS ≥−12% was found to be equivalent to an EF ≤35% for the prediction of prognosis. Intraobserver and interobserver variations for EF and GLS were similar.

Conclusions—

GLS is a superior predictor of outcome to either EF or WMSI and may become the optimal method for assessment of global left ventricular systolic function.
An Integral Upper Bound for Neural Network Approximation
Authors: Kainen Paul C. , Kůrková Věra
Published: July 2009

Complexity of one-hidden-layer networks is studied using tools from nonlinear approximation and integration theory. For functions with suitable integral representations in the form of networks with infinitely many hidden units, upper bounds are derived on the speed of decrease of approximation error as the number of network units increases. These bounds are obtained for various norms using the framework of Bochner integration. Results are applied to perceptron networks.
A Dynamic Causal Model of the Coupling Between Pulse Stimulation and Neural Activity
Authors: Lefebvre Veronique , Zheng Ying , Martin Chris , Devonshire Ian M. , Harris Samuel , Mayhew John E.
Published: July 2009

We present a dynamic causal model that can explain context-dependent changes in neural responses, in the rat barrel cortex, to an electrical whisker stimulation at different frequencies. Neural responses were measured in terms of local field potentials. These were converted into current source density (CSD) data, and the time series of the CSD sink was extracted to provide a time series response train. The model structure consists of three layers (approximating the responses from the brain stem to the thalamus and then the barrel cortex), and the latter two layers contain nonlinearly coupled modules of linear second-order dynamic systems. The interaction of these modules forms a nonlinear regulatory system that determines the temporal structure of the neural response amplitude for the thalamic and cortical layers.

The model is based on the measured population dynamics of neurons rather than the dynamics of a single neuron and was evaluated against CSD data from experiments with varying stimulation frequency (1–40 Hz), random pulse trains, and awake and anesthetized animals. The model parameters obtained by optimization for different physiological conditions (anesthetized or awake) were significantly different.

Following Friston, Mechelli, Turner, and Price ( 2000 ), this work is part of a formal mathematical system currently being developed (Zheng et al., 2005 ) that links stimulation to the blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal through neural activity and hemodynamic variables. The importance of the model described here is that it can be used to invert the hemodynamic measurements of changes in blood flow to estimate the underlying neural activity.
Experience-Induced Neural Circuits That Achieve High Capacity
Authors: Feldman Vitaly , Valiant Leslie G.
Published: July 2009

Over a lifetime, cortex performs a vast number of different cognitive actions, mostly dependent on experience. Previously it has not been known how such capabilities can be reconciled, even in principle, with the known resource constraints on cortex, such as low connectivity and low average synaptic strength. Here we describe neural circuits and associated algorithms that respect the brain's most basic resource constraints and support the execution of high numbers of cognitive actions when presented with natural inputs. Our circuits simultaneously support a suite of four basic kinds of task, each requiring some circuit modification: hierarchical memory formation, pairwise association, supervised memorization, and inductive learning of threshold functions. The capacity of our circuits is established by experiments in which sequences of several thousand such actions are simulated by computer and the circuits created tested for subsequent efficacy. Our underlying theory is apparently the only biologically plausible systems-level theory of learning and memory in cortex for which such a demonstration has been performed, and we argue that no general theory of information processing in the brain can be considered viable without such a demonstration.
Operant Matching as a Nash Equilibrium of an Intertemporal Game
Authors: Loewenstein Yonatan , Prelec Drazen , Seung H. Sebastian
Published: July 2009

Over the past several decades, economists, psychologists, and neuroscientists have conducted experiments in which a subject, human or animal, repeatedly chooses between alternative actions and is rewarded based on choice history. While individual choices are unpredictable, aggregate behavior typically follows Herrnstein's matching law: the average reward per choice is equal for all chosen alternatives. In general, matching behavior does not maximize the overall reward delivered to the subject, and therefore matching appears inconsistent with the principle of utility maximization. Here we show that matching can be made consistent with maximization by regarding the choices of a single subject as being made by a sequence of multiple selves—one for each instant of time. If each self is blind to the state of the world and discounts future rewards completely, then the resulting game has at least one Nash equilibrium that satisfies both Herrnstein's matching law and the unpredictability of individual choices. This equilibrium is, in general, Pareto suboptimal, and can be understood as a mutual defection of the multiple selves in an intertemporal prisoner's dilemma.

The mathematical assumptions about the multiple selves should not be interpreted literally as psychological assumptions. Human and animals do remember past choices and care about future rewards. However, they may be unable to comprehend or take into account the relationship between past and future. This can be made more explicit when a mechanism that converges on the equilibrium, such as reinforcement learning, is considered.

Using specific examples, we show that there exist behaviors that satisfy the matching law but are not Nash equilibria. We expect that these behaviors will not be observed experimentally in animals and humans. If this is the case, the Nash equilibrium formulation can be regarded as a refinement of Herrnstein's matching law.
A Neurocomputational Model for Cocaine Addiction
Authors: Dezfouli Amir , Piray Payam , Keramati Mohammad Mahdi , Ekhtiari Hamed , Lucas Caro , Mokri Azarakhsh
Published: July 2009

Based on the dopamine hypotheses of cocaine addiction and the assumption of decrement of brain reward system sensitivity after long-term drug exposure, we propose a computational model for cocaine addiction. Utilizing average reward temporal difference reinforcement learning, we incorporate the elevation of basal reward threshold after long-term drug exposure into the model of drug addiction proposed by Redish. Our model is consistent with the animal models of drug seeking under punishment. In the case of nondrug reward, the model explains increased impulsivity after long-term drug exposure. Furthermore, the existence of a blocking effect for cocaine is predicted by our model.
Distance Learning in Discriminative Vector Quantization
Authors: Schneider Petra , Biehl Michael , Hammer Barbara
Published: July 2009

Discriminative vector quantization schemes such as learning vector quantization (LVQ) and extensions thereof offer efficient and intuitive classifiers based on the representation of classes by prototypes. The original methods, however, rely on the Euclidean distance corresponding to the assumption that the data can be represented by isotropic clusters. For this reason, extensions of the methods to more general metric structures have been proposed, such as relevance adaptation in generalized LVQ (GLVQ) and matrix learning in GLVQ. In these approaches, metric parameters are learned based on the given classification task such that a data-driven distance measure is found. In this letter, we consider full matrix adaptation in advanced LVQ schemes. In particular, we introduce matrix learning to a recent statistical formalization of LVQ, robust soft LVQ, and we compare the results on several artificial and real-life data sets to matrix learning in GLVQ, a derivation of LVQ-like learning based on a (heuristic) cost function. In all cases, matrix adaptation allows a significant improvement of the classification accuracy. Interestingly, however, the principled behavior of the models with respect to prototype locations and extracted matrix dimensions shows several characteristic differences depending on the data sets.
Taming Fluctuations in a Stochastic Model of Spike-Timing-Dependent Plasticity
Authors: Elliott Terry , Lagogiannis Konstantinos
Published: July 2009

A stochastic model of spike-timing-dependent plasticity proposes that single synapses express fixed-amplitude jumps in strength, the amplitudes being independent of the spike time difference. However, the probability that a jump in strength occurs does depend on spike timing. Although the model has a number of desirable features, the stochasticity of response of a synapse introduces potentially large fluctuations into changes in synaptic strength. These can destabilize the segregated patterns of afferent connectivity characteristic of neuronal development. Previously we have taken these jumps to be small relative to overall synaptic strengths to control fluctuations, but doing so increases developmental timescales unacceptably. Here, we explore three alternative ways of taming fluctuations. First, a calculation of the variance for the change in synaptic strength shows that the mean change eventually dominates fluctuations, but on timescales that are too long. Second, it is possible that fluctuations in strength may cancel between synapses, but we show that correlations between synapses emasculate the law of large numbers. Finally, by separating plasticity induction and expression, we introduce a temporal window during which induction signals are low-pass-filtered before expression. In this way, fluctuations in strength are tamed, stabilizing segregated states of afferent connectivity.
What the students bring: examining the attributes of commencing conservatoire students
Authors: Lebler Don , Burt-Perkins Rosie , Carey Gemma
Published: July 2009

As the range of experiences offered by conservatoires expands to serve an increasingly diverse student cohort, it is no longer reasonable to assume that all students will fit neatly into the traditional expectations of institutions. In the 3P model of learning, the prior learning of students is one of the presage factors that interact with process factors to create products of the system; all three sets of factors should be considered when exploring a learning system. This study explores students' preconservatoire music-learning experiences and attitudes in one bachelor of (western classical) music program in the UK and a similar program in Australia, where a popular music cohort was also studied. Results indicate that prior learning experiences and expectations differ among all three cohorts, raising pertinent questions about the need to reject a `one-model-fits-all' approach to curriculum development. Working from the data, potential lessons from the popular music context are proposed for consideration in the processes of the classical context.
Learning design and proscription: how generative activity was promoted in music composing
Authors: Breeze Nick
Published: July 2009

This article reports on a particular aspect of a PhD study into pupil composing in music classrooms with information and communications technology (ICT). Two case studies based in England investigated the work of two groups of pupils in different phases of education, one aged 12—13 (secondary) and the other 10—11 (primary). A theoretical lens that was utilized to illuminate a specific aspect of the learning design was that of proscription, which not only allowed a detailed investigation of pupils' generative activity to be made, but also revealed aspects about the learning environment that often remain tacit and hence unexplored. A key outcome of the study was the suggestion that the notion of proscription be extended to one of providing the possibility of moving beyond given constraints to compose music that lies outside their boundaries.
A descriptive study of high school and university students' focus of attention in fast and slow orchestral excerpts
Authors: Macleod Rebecca B. , Geringer John M. , Scott Laurie
Published: July 2009

The purpose of this study was to investigate listener discrimination of orchestral performances and to ascertain focus of listener attention to technical and expressive music elements of those performances. High School ( n = 84) and University ( n = 84) music students listened to four orchestral excerpts: two slow/soft excerpts and two fast/loud excerpts. Recordings representing three levels of performance were presented: high school, university and professional. Listeners rated excerpts on accuracy and musicality, and identified the most noticeable element of each performance. Results indicated that listeners discriminated between performance levels. In the slow excerpts, university students noticed intonation and tone most frequently, while high school students noticed dynamics and tone. For the fast examples, university students noted dynamics, accuracy and articulation. High school students noticed dynamics overwhelmingly. Listeners noticed a wide variety of elements for the slow examples, whereas responses were more similar for the fast excerpts.
Participant approaches to and reflections on learning to play a 12-bar blues in an asynchronous e-learning environment
Authors: Seddon Frederick , Biasutti Michele
Published: July 2009

This study investigated the viability of learning to play an improvised 12-bar blues on keyboard with both hands together in an asynchronous e-learning environment. The study also sought to reveal participant approaches to and reflections on this learning experience. Participants were video-taped as they engaged with six `Blues Activities', supported by audio `guide' and `backing' tracks and a `remote facilitator'. Participants required nine or ten learning sessions, over a period of six weeks, to successfully complete the `Blues Activities'. Individual, semi-structured interviews, designed to reveal participant reflections on their engagement with the `Blues Activities' were conducted with the participants after they had completed the learning sessions. Results revealed that: (1) at the end of the learning sessions, all participants were able to play the 12-bar improvised blues; (2) participants engaged in five distinct learning behaviours; and (3) four participant `reflective themes' emerged from the semi-structured interviews. The five distinct learning behaviours were interpreted as `learning activities': `instruction', `copying', `practising', `playing' and `evaluating'. The four `reflective themes' were interpreted as: `activities', `feelings', `evaluation' and `difficulties'. Comments made by participants during interviews and email exchanges, provided support for the researcher interpretations of the `learning activities' and `reflective themes' through the process of triangulation. Implications for music education are discussed.
Assessment of undergraduate students' music compositions
Authors: Chi Cheung Leung  , Yu Ying Wan  , Lee Anthony
Published: July 2009

This study aims to investigate and identify the criteria and parameters for assessing compositions, and how assessment can help students' learning. Participants in the study include three composer-assessors and six undergraduate music students. An assessment framework for music composition based on both the macro and micro philosophies of assessing music compositions was established. Assessment results, written comments and interview data from the composer-assessors and the student-composers were collected and analysed. A Rasch measurement model was the main tool for calibrating a stable and unified assessment scale based on subjectively rated data, and it provided a solution for standardizing ratings of assessors with different levels of severity in their ratings. The study revealed that both macro and micro aspects of assessing composition were important but assessors weighted heavier on the micro skills; supportive feedback and comments served to facilitate students to improve their works; and the framework was proven to be an effective tool in assessing music composition.
Labour Migration and Ties of Relatedness: Diasporic Houses and Investments in Memory in a Rural Philippine Village
Authors: Aguilar Filomeno
Published: July 2009

Putting migrant remittances into house construction and rebuilding is generally seen as either conspicuous consumption or productive investment, but in both cases the perspective is economistic. This article argues that only when the cultural dimension of economic action is understood will it be possible to comprehend migrant spending on houses. Specifically, this article seeks to understand why, in the case of the rural Tagalog village in this study, located in upland Batangas Province in the Philippines, overseas labour migrants build houses that they do not even live in, but are given to parents or simply left unoccupied. The explanation is framed in relation to the meanings of houses in a culture of bilateral kinship, which the Philippines shares with most parts of Southeast Asia, but inflected by distinct colonial influences. The article demonstrates the ways in which houses as memorials serve as idioms of ties of relatedness within kin groups and the broader community, ties that are being transformed by global migration and experienced differently yet maintained, renegotiated yet sustained transnationally.
Contesting/Negotiating Power and Domination on the US — Mexico Border
Authors: Bhimji Fazila
Published: July 2009

The article examines the ways in which twenty Mexican and five Central Americans male undocumented migrants construct the border in varying ways while they speak of their work conditions and their encounters and perceptions of the border patrol agents on the Texas/Mexico border area. Many of them who work as construction workers are economically exploited since they are paid below standard minimum wages. The temporary migrant workers display knowledge of their rights and entitlements through discursive practices such as evaluations, knowledge of their exploitative conditions, and resolutions to move further into the US or to find alternative means of income. In doing so, the migrants construct the border in many instances as a transitional space which is rather exploitative. More significantly, the undocumented migrants tend to differ in the ways in which they experience the border. Despite the militarization and exploitative work conditions for some undocumented migrants the border is perceived as relatively fluid. While for other immigrant groups such as Central Americans, migrants with past criminal records, and younger demonized males the border is more enclosed where they have to contend with power structures on a different level. There has been much focus on the border and border narratives across various disciplines but little attention has been given to the ways in which undocumented migrants experience the border during their temporary stay in order to transition to further points in the US such as Dallas, Los Angeles, and Denver. Data are based on participant observation, informal conversations, and recorded interviews of 25 male undocumented migrants residing at a temporary shelter in El Paso, Texas, over two summer periods in the years 2006 and 2007.
Transnational Gender Studies and the Migrating Concept of Gender in the Middle East and North Africa
Authors: Hale Sondra
Published: July 2009

This article is an attempt to capture aspects of ramifying networks that are transporting the fluid concept of `gender'. Assuming that transnationality is a central feature in diasporic contexts, how does it manifest itself in diasporic practices? If one of these practices is knowledge production, then what are the processes of migrating epistemologies and how are these gendered? This begs the question of whether or not gender is still an important site from which to view the fluid phenomena of postcolonial/transnational processes or if the contemporary valences of transnationalism require, instead, a fluid gendering of the contemporary categories of empire that operate differently through space. By reading the transnational through the local, with particular reference to Ahfad University for Women (Sudan), the article interrogates the ways concepts of women/gender and feminist ideas travel across boundaries and how these concepts are changed in the process.
The end of the disinterested profession: The American Institute of Certified Public Accountants and the union corruption scandals, 1957—62
Authors: Doron Michael E.
Published: July 2009

American accounting histories of the mid-twentieth century have long focused on the development of accounting standards. With the exception of the events surrounding the New Deal, there has been a reliance on memoirs and official histories for analysis of the accounting profession itself. The union corruption scandals and the accounting profession's efforts to involve itself in the reform of unions and pensions offers an opportunity to see how the profession understood and consolidated its franchise in financial statement audits and, perhaps more importantly, how it saw its own place in American society and how its place was viewed by others. This article focuses on the events that led to the passage of the Labor Management Reporting and Disclosure Act (Landrum-Griffin Act) of 1959, paying particular attention to congressional testimony and the records of congressmen and the Eisenhower administration and the efforts of the American Institute of Certified Public Accountants to influence the legislation.
Accounting for the “good administration of justice”: The Farnese State of Abruzzo in the sixteenth century
Authors: Sargiacomo Massimo
Published: July 2009

Accounting historians have rarely investigated the role of accounting in the administration of justice. Drawing on Foucault's “governmentality” framework, this article explores the 1571 Ordinances enacted by Margaret of Austria that specifically regulated and shaped the behaviour of officers working within the justice apparatus of the State's towns and lands. The article documents the role played by accounting, and especially financial information, in the administration of the sixteenth-century justice offices with a focus on the use of that information for the control of magistrates/officers working in the decentralized apparatus. The study provides evidence of the major technologies of government enforced by Margaret of Austria for the “good administration of justice”, and devoted to the removal of the “bad order of Tribunals” and to assist in the elimination of “abuses”. The article also seeks to enhance our understanding of accounting by highlighting the interplay between justice and accounting officers and their functions.
Subchronic Oral Toxicity of Salcaprozate Sodium (SNAC) in Sprague-Dawley and Wistar Rats
Authors: Riley M. Gary I. , Castelli M. Cristina , Paehler Ellen Angela
Published: July 2009

Salcaprozate sodium (SNAC) (sodium 8-((2-hydroxybenzoyl) amino) octanoate, CAS RN 203787-91-1) is classified as an oral absorption promoter, and its potential therapeutic applications as a delivery agent for oral forms of heparin and insulin have been explored in a number of clinical investigations. However, limited information about its nonclinical safety is available in the published scientific literature. As part of a larger study exploring the safety of SNAC in combination with heparin, Sprague-Dawley (SD) rats (20/sex/group) received SNAC alone at 2000 mg/kg/d orally (gavage) for 13 weeks (females were terminated after 10 weeks). In a separate study assessing the safety of SNAC in combination with ibandronate, Wistar rats (10/sex/group) received SNAC alone at levels of 100, 500, or 1000 mg/kg/d orally for 13 weeks. SNAC-related mortality was evident only at the 2000-mg/kg/d level, 20% among males and 50% among females; no clear cause of death was evident. No mortality was seen in the Wistar rat study at doses up to 1000 mg/kg/d. Some differences in clinical pathology parameters, including slightly altered electrolyte levels and lower globulin levels, were seen in SD and Wistar rats. Although these differences reached statistical significance, parameters were within historical control ranges. Liver and kidney weights were slightly higher in SNAC-treated animals of both strains, with no corresponding histopathological changes. These changes may therefore constitute an adaptive response. Histopathological changes were seen in the stomach in both studies, probably secondary to irritation caused by the dosing method. Based on the results of these studies, a no-observed-adverse-effect level (NOAEL) cannot be given for SD rats. The NOAEL for SNAC in Wistar rats was considered to be 1000 mg/kg/d.