bluuebunny/crossref_metadata_2025 huggingface dataset:
Partial‐volume effect on ischemic tissue‐fate delineation using quantitative perfusion and diffusion imaging on a rat stroke model
Authors: Ren Hongxia , Shen Qiang , Bardutzky Juergen , Fisher Marc , Duong Timothy Q.
Published: November 2004

Partial‐volume effects (PVE) in stroke imaging could hinder proper delineation of normal, ischemic, and at‐risk tissues. Cerebral‐blood‐flow (CBF) and apparent diffusion coefficient (ADC) were measured at high and low resolution (HR = 128 × 128, LR = 64 × 64) in focal ischemia in rats during the acute phase. The data were evaluated for PVE on ischemic tissue classification on a pixel‐by‐pixel basis and the misclassified pixels were quantified as ischemia progressed. The main drawbacks of high‐resolution imaging are reduced temporal resolution and/or signal‐to‐noise ratio. The high‐ versus low‐resolution scatterplots and histograms of pixels along the normal–abnormal boundaries in the ADC and CBF maps showed marked ischemia‐related PVE. By comparison with the homologous regions in the contralateral normal hemisphere, the effect of increased noise and intrinsic tissue heterogeneity due to high resolution could be distinguished from ischemia‐related PVE. Degrading the high‐resolution (128 × 128) data to a 64 × 64 or 32 × 32 matrix increased the severity of PVE. Zero‐filling of low‐resolution (64 × 64) data to 128 × 128 also increased PVE. It was concluded that PVE: (1) misclassified substantial pixels along the normal–abnormal boundaries, (2) overestimated abnormal volumes at the expense of mostly “at‐risk” and some “normal” tissues, (3) were more severe at the early time points postischemia, and (4) confounded the interpretation of the operationally defined ischemic penumbra. Magn Reson Med 52:1328–1335, 2004. © 2004 Wiley‐Liss, Inc.
The Improvisation-Efficiency Paradox in Inter-Firm Electronic Networks: Governance and Architecture Considerations
Authors: Konsynski Benn , Tiwana Amrit
Published: November 2004

The need to simultaneously achieve operational efficiency, while accommodating a continuous morphing of alliances and network arrangements, is a key challenge in the modern enterprise and market. Inter-firm interdependence and unpredictable market shifts heighten the need to establish an architecture and governance arrangement that permits rapid adaptation. Fully integrated firms have increasingly morphed into networks of collaborators. The demand for efficient and effective inter-firm coordination is no longer a desired condition, but essential for competitive position. Historically, the cost of this efficiency has been loss of flexibility, yet volatile markets reward efficiency and flexibility. Market trends demand an ability to improvise in the marketplace - converge execution with planning - while being simultaneously efficient. In this paper, we explore this improvisation-efficiency paradox. The architecture and governance issues are considered that seek the strengths of both effects. Efficiency need not come at a high cost in attaining the ability to be adaptive and spontaneous. We explore the key considerations of both network architecture and governance structures that characterize improvisational networks. Trade communities and trading partners establish a discipline of processes and decision rights that serve the community of collaborators.
A locus for sodium exclusion (Nax1), a trait for salt tolerance, mapped in durum wheat
Authors: Lindsay Megan P. , Lagudah Evans S. , Hare Ray A. , Munns Rana
Published: November 2004

Salinity affects durum wheat [Triticum turgidum L. ssp. durum (Desf.)] more than it affects bread wheat (Triticum aestivum L.), and results in lower yield for durum wheat cultivars grown on salt-affected soils. A novel source of salt tolerance in the form of a sodium exclusion trait, identified previously in a screen of tetraploid wheat germplasm, was mapped using a QTL approach. The trait, measured as low Na+ concentration in the leaf blade, was mapped on a population derived from a cross between the low Na+ landrace and the cultivar Tamaroi. The use of AFLP, RFLP and microsatellite markers identified a locus, named Nax1 (Na exclusion), on chromosome 2AL, which accounted for approximately 38% of the phenotypic variation in the mapping population. Markers linked to the Nax1 locus also associated closely with low Na+ progeny in a genetically unrelated population. A microsatellite marker closely linked to the Nax1 locus was validated in genetically diverse backgrounds, and proven to be useful for marker-assisted selection in a durum wheat breeding program.
Solution structure of the CD3εδ ectodomain and comparison with CD3εγ as a basis for modeling T cell receptor topology and signaling
Authors: Sun Zhen-Yu J. , Kim Sun Taek , Kim Il Chul , Fahmy Amr , Reinherz Ellis L. , Wagner Gerhard
Published: November 2004

Invariant CD3 subunit dimers (CD3εγ, CD3εδ, and CD3ζζ) are the signaling components of the αβ T cell receptor (TCR). The recently solved structure of murine CD3εγ revealed a unique side-to-side interface and central β-sheets conjoined between the two C2-set Ig-like ectodomains, with the pairing of the parallel G strands implying a potential concerted piston-type movement for signal transduction. Although CD3γ and CD3δ each dimerize with CD3ε, there are differential CD3 subunit requirements for receptor assembly and signaling among T lineage subpopulations, presumably mandated by structural differences. Here we present the solution structure of the heterodimeric CD3εδ complex. Whereas the CD3ε subunit conformation is virtually identical to that in CD3εγ, the CD3δ ectodomain adopts a C1-set Ig fold, with a narrower GFC front face β-sheet that is more parallel to the ABED back face than those β-sheets in CD3ε and CD3γ. The dimer interface between CD3δ and CD3ε is highly conserved among species and of similar character to that in CD3εγ. Glycosylation sites in CD3δ are arranged such that the glycans may point away from the membrane, consistent with a model of TCR assembly that allows the CD3δ chain to be in close contact with the TCR α-chain. This and many other structural and biological features provide a basis for modeling putative TCR/CD3 extracellular domain associations. The fact that the two clusters of transmembrane helices, namely, the three CD3ε–CD3γ–TCRβ segments and the five CD3ε–CD3δ–TCRα–CD3ζ–CD3ζ segments, are presumably centered beneath the G strand-paired CD3 heterodimers has important implications for TCR signaling.
Perceptual deficits in patients with impaired recognition of biological motion after temporal lobe lesions
Authors: Vaina Lucia M. , Gross Charles G.
Published: November 2004

“Biological motion” may be defined by the pattern of movement of a small number of lights attached to the major joints of a human performing simple actions. Normal observers watching such displays immediately recognize a person and his or her actions. In the present study, we investigated the effects of lesions of anterior cortical regions on the perception of biological motion. We measured the performance on psychophysical static and motion tasks and on object and action recognition tests in four stroke patients who presented with a disorder of recognition of biological motion. We relate our results to the finding that neurons in the rostral part of the superior temporal gyrus (the superior temporal polysensory area) respond selectively to biological motion, and to the idea that the superior temporal polysensory area integrates the late stages of the dorsal and ventral cortical visual streams, as well as to recent functional MRI studies on biological motion.
Sarcolipin retention in the endoplasmic reticulum depends on its C-terminal RSYQY sequence and its interaction with sarco(endo)plasmic Ca
2
+-ATPases
Authors: Gramolini Anthony O. , Kislinger Thomas , Asahi Michio , Li Wenping , Emili Andrew , MacLennan David H.
Published: November 2004

Sarcolipin (SLN) and phospholamban (PLN) are effective inhibitors of the sarco(endo)plasmic reticulum Ca
2+
-ATPase (SERCA). These homologous proteins differ at their N and C termini: the C-terminal Met-Leu-Leu in PLN is replaced by Arg-Ser-Tyr-Gln-Tyr in SLN. The role of the C-terminal sequence of SLN tagged N-terminally with the FLAG epitope (NF-SLN) in endoplasmic reticulum (ER) retention was investigated by transfecting human embryonic kidney-293 cells with cDNAs encoding NF-SLN or a series of NF-SLN mutants in which C-terminal amino acids were deleted progressively. Immunofluorescence and immunoblotting of transfected cells by using anti-FLAG antibodies indicated that NF-SLN and PLN tagged at its N terminus with the FLAG epitope, even when overexpressed, were restricted to the ER. However, C-terminal truncation deletions of SLN, which lacked RSYQY, were not localized to ER and did not inhibit Ca
2+
-dependent Ca
2+
uptake by SERCA. The shortest deletion constructs, NF-SLN 1-22 and NF-SLN 1-23, did not express stable protein products. However, all NF-SLN cDNA constructs, including NF-SLN 1-22 and NF-SLN 1-23, were expressed stably and localized to the ER when they were coexpressed with SERCA2a. These results show that NF-SLN subcellular distribution depends on SERCA coexpression and on its luminal, C-terminal RSYQY sequence. By using immunoprecipitation and MS, glucose-regulated protein 78/BiP and glucose-regulated protein 94 were identified as proteins that interact with NF-SLN through the RSYQY sequence. Thus, in the absence of SERCA, retention of NF-SLN in the ER is mediated through its association with other components through the C-terminal RSYQY sequence.
The dominance of Kenyans in distance running
Authors: Pitsiladis Yannis P , Onywera Vincent O , Geogiades Evelina , O'Connell William , Boit Michael K
Published: November 2004

Kenyan runners, and especially those originating from the Kalenjin tribe, have dominated international middle- and long-distance running for over 40 years, prompting significant interest in the factors contributing to their success. Proposed explanations have included environmental factors, psychological advantage and favourable physiological characteristics, which may be genetically conferred or environmentally determined. Running is inherent within local Kenyan tradition and culture, and the Kenyan way of life, which involves many outdoor activities and pastimes in addition to mostly unfavourable living conditions, is conducive to enhanced distance running performance. Despite economic deprivation, Kenya has produced world and international running champions repeatedly over the past few decades; these champions have become role models for the younger generations, who take up running in the hope of a better future for themselves. Favourable environmental conditions such as altitude, diet and anthropometry, in addition to the motivational and socio-economic factors mentioned above, have all been proposed as possible reasons for the unsurpassed achievements of Kenyan distance runners. However, the fact that the majority of internationally successful runners originate from a small tribe that accounts for approximately 3% of the total Kenyan population also points to a possible genetic component. Whether this is subject to influence from other co-factors, such as altitude or training effects acquired during childhood, remains as yet unresolved.
Probabilistic cross‐link analysis and experiment planning for high‐throughput elucidation of protein structure
Authors: Ye Xiaoduan , O'Neil Patrick K. , Foster Adrienne N. , Gajda Michal J. , Kosinski Jan , Kurowski Michal A. , Bujnicki Janusz M. , Friedman Alan M. , Bailey‐Kellogg Chris
Published: November 2004

Emerging high‐throughput techniques for the characterization of protein and protein‐complex structures yield noisy data with sparse information content, placing a significant burden on computation to properly interpret the experimental data. One such technique uses cross‐linking (chemical or by cysteine oxidation) to confirm or select among proposed structural models (e.g., from fold recognition, ab initio prediction, or docking) by testing the consistency between cross‐linking data and model geometry. This paper develops a probabilistic framework for analyzing the information content in cross‐linking experiments, accounting for anticipated experimental error. This framework supports a mechanism for planning experiments to optimize the information gained. We evaluate potential experiment plans using explicit trade‐offs among key properties of practical importance: discriminability, coverage, balance, ambiguity, and cost. We devise a greedy algorithm that considers those properties and, from a large number of combinatorial possibilities, rapidly selects sets of experiments expected to discriminate pairs of models efficiently. In an application to residue‐specific chemical cross‐linking, we demonstrate the ability of our approach to plan experiments effectively involving combinations of cross‐linkers and introduced mutations. We also describe an experiment plan for the bacteriophage λ Tfa chaperone protein in which we plan dicysteine mutants for discriminating threading models by disulfide formation. Preliminary results from a subset of the planned experiments are consistent and demonstrate the practicality of planning. Our methods provide the experimenter with a valuable tool (available from the authors) for understanding and optimizing cross‐linking experiments.
On the use of DXMS to produce more crystallizable proteins: Structures of the T. maritima proteins TM0160 and TM1171
Authors: Spraggon Glen , Pantazatos Dennis , Klock Heath E. , Wilson Ian A. , Woods Virgil L. , Lesley Scott A.
Published: November 2004

The structure of two Thermotoga maritima proteins, a conserved hypothetical protein (TM0160) and a transcriptional regulator (TM1171), have now been determined at 1.9 Å and 2.3 Å resolution, respectively, as part of a large‐scale structural genomics project. Our first efforts to crystallize full‐length versions of these targets were unsuccessful. However, analysis of the recombinant purified proteins using the technique of enhanced amide hydrogen/deuterium exchange mass spectroscopy (DXMS) revealed substantial regions of rapid amide deuterium hydrogen exchange, consistent with flexible regions of the structures. Based on these exchange data, truncations were designed to selectively remove the disordered C‐terminal regions, and the resulting daughter proteins showed greatly enhanced crystallizability. Comparative DXMS analysis of full‐length protein versus truncated forms demonstrated complete and exact preservation of the exchange rate profiles in the retained sequence, indicative of conservation of the native folded structure. This study presents the first structures produced with the aid of the DXMS method for salvaging intractable crystallization targets. The structure of TM0160 represents a new fold and highlights the use of this approach where any prior structural knowledge is absent. The structure of TM1171 represents an example where the lack of a substrate/cofactor may impair crystallization. The details of both structures are presented and discussed.
Financial Development and Intersectoral Allocation: A New Approach
Authors: FISMAN RAYMOND , LOVE INESSA
Published: November 2004

This paper uses a new methodology based on industry comovement to examine the role of financial market development in intersectoral allocation. Based on the assumption that there exist common global shocks to growth opportunities, we hypothesize that country pairs should have correlated patterns of sectoral growth if they are able to respond to these shocks. Consistent with financial markets promoting responsiveness to shocks, countries have more highly correlated growth rates across sectors when both countries have well‐developed financial markets. This effect is stronger between country pairs at similar levels of economic development, which are more likely to experience similar growth shocks.
Do Initial Public Offering Firms Purchase Analyst Coverage with Underpricing?
Authors: CLIFF MICHAEL T. , DENIS DAVID J.
Published: November 2004

We report that initial public offering (IPO) underpricing is positively related to analyst coverage by the lead underwriter and to the presence of an all‐star analyst on the research staff of the lead underwriter. These findings are robust to controls for other determinants of underpricing and to controls for the endogeneity of underpricing and analyst coverage. In addition, we find that the probability of switching underwriters between IPO and seasoned equity offering is negatively related to the unexpected amount of post‐IPO analyst coverage. These findings are consistent with the hypothesis that underpricing is, in part, compensation for expected post‐IPO analyst coverage from highly ranked analysts.
DPIV Measurements of Flow Disturbances in Stented Artery Models: Adverse affects of Compliance Mismatch
Authors: Yazdani Saami K. , Moore, James E. , Berry Joel L. , Vlachos Pavlos P.
Published: November 2004

Vascular stents influence the post-procedural hemodynamic environment in ways that may encourage restenosis. Understanding how stents influence flow patterns may lead to more hemodynamically compatible stent designs that alleviate thrombus formation and promote endothelialization. This study employed time-resolved Digital Particle Image Velocimetry (DPIV) to compare the hemodynamic performance of two stents in a compliant vessel. The first stent was a rigid insert, representing an extreme compliance mismatch. The second stent was a commercially available nitinol stent with some flexural characteristics. DPIV showed that compliance mismatch promotes the formation of a ring vortex in the vicinity of the stent. Larger compliance mismatch increased both the size and residence time of the ring vortex, and introduced in-flow stagnation points. These results provide detailed quantitative evidence of the hemodynamic effect of stent mechanical properties. Better understanding of these characteristics will provide valuable information for modifying stent design in order to promote long-term patency.
Apical Organelle Discharge by
Cryptosporidium parvum
Is Temperature, Cytoskeleton, and Intracellular Calcium Dependent and Required for Host Cell Invasion
Authors: Chen Xian-Ming , O'Hara Steven P. , Huang Bing Q. , Nelson Jeremy B. , Lin Jim Jung-Ching , Zhu Guan , Ward Honorine D. , LaRusso Nicholas F.
Published: November 2004

The apical organelles in apicomplexan parasites are characteristic secretory vesicles containing complex mixtures of molecules. While apical organelle discharge has been demonstrated to be involved in the cellular invasion of some apicomplexan parasites, including
Toxoplasma gondii
and
Plasmodium
spp., the mechanisms of apical organelle discharge by
Cryptosporidium parvum
sporozoites and its role in host cell invasion are unclear. Here we show that the discharge of
C. parvum
apical organelles occurs in a temperature-dependent fashion. The inhibition of parasite actin and tubulin polymerization by cytochalasin D and colchicines, respectively, inhibited parasite apical organelle discharge. Chelation of the parasite's intracellular calcium also inhibited apical organelle discharge, and this process was partially reversed by raising the intracellular calcium concentration by use of the ionophore A23187. The inhibition of parasite cytoskeleton polymerization by cytochalasin D and colchicine and the depletion of intracellular calcium also decreased the gliding motility of
C. parvum
sporozoites. Importantly, the inhibition of apical organelle discharge by
C. parvum
sporozoites blocked parasite invasion of, but not attachment to, host cells (i.e., cultured human cholangiocytes). Moreover, the translocation of a parasite protein, CP2, to the host cell membrane at the region of the host cell-parasite interface was detected; an antibody to CP2 decreased the
C. parvum
invasion of cholangiocytes. These data demonstrate that the discharge of
C. parvum
sporozoite apical organelle contents occurs and that it is temperature, intracellular calcium, and cytoskeleton dependent and required for host cell invasion, confirming that apical organelles play a central role in
C. parvum
entry into host cells.
Gender-specific dispersal distances of grizzly bears estimated by genetic analysis
Authors: Proctor Michael F , McLellan Bruce N , Strobeck Curtis , Barclay Robert M.R
Published: November 2004

Natal dispersal is difficult to quantify, and long-distance events are often undetected, leading to biased estimates. Following offspring from their natal home range to their postdispersal adult breeding home range is challenging, and gathering sufficient data for large mammals with long generation times is particularly difficult. Here we measure average sex-specific dispersal distances in grizzly bears (Ursus arctos L., 1758) using individual-based genetic analysis. We genetically sampled and generated 15-locus microsatellite genotypes for 711 grizzly bears over a range of 100 000 km2in southwestern Canada. Microsatellite markers are inherited in a Mendelian fashion, allowing us to use likelihood-based parentage analyses to estimate parent–offspring dyads. We used the distance between individually captured females of parent–offspring pairs (i.e., mother–daughter) to estimate female natal dispersal distances and found that, on average, females dispersed 14.3 km from the center of their natal home range. We used the distance between males of parent–offspring pairs (i.e., father–son) to estimate average male dispersal distances and found that males dispersed, on average, 41.9 km from their natal, or maternal, home range (mother–son dispersal distance). We used a simulation model to estimate the bias associated with measuring the father–son (male–male) distance as an estimate of the mother–son distance.
Should I brood or should I hunt: a female barn owl's dilemma
Authors: Durant Joël M , Gendner Jean-Paul , Handrich Yves
Published: November 2004

While brooding, many female raptors rely exclusively on food provisioning from males. Thus, they may forego hunting until young are about half grown before exiting the nest to undertake a first foraging trip. To investigate the mechanisms that trigger this first foraging exit, we analysed nest food provisioning, female body mass change, and nestling and female food requirements in regard to exit date in five pairs of barn owls, Tyto alba (Scopoli, 1769), nesting in eastern France. Adult mass and behaviour were monitored using an automated weighing system and a video camera. Our results indicate that the first foraging exit of the female occurs about 15 days after the hatching of the first egg. This reinitiation of foraging occurs at about the same time that male food provisioning no longer matches nestling food requirements — about 17 days after the hatching of the first egg. Thus the timing of the female's first hunting trip may be primarily adjusted to a discrepancy between brood food requirements and available food supply. Additionally, we found that females started to lose mass, on average, 6 days before their first hunting trip through a reduction of food intake, and we discuss the potential mechanisms and implications.
EFFICIENT PARALLEL IMPLEMENTATION OF KOGBETLIANTZ'S SVD ALGORITHM
Authors: GÖTZE JÜRGEN
Published: November 2004

In this paper efficient implementations of Kogbetliantz's algorithm for computing the singular value decomposition (SVD) of an m × n (m ≥ n) matrix on an upper triangular array of processors are presented. Modifications of the rotation evaluations, as approximations and factorizations of the rotations, are considered in order to obtain a reduction of the hardware and time requirements of the processor array. Particularly, it is shown that only the combination of these modifications enables the derivation of square root free or square root and division free algorithms.
PARALLEL-TRANSPORTED MULTIGRID BEATS CONJUGATE GRADIENT
Authors: SOLOMON S. , LAUWERS P.G.
Published: November 2004

The convergence rates for inverting the Dirac matrix in the SU(2) gauge theory on a square two-dimensional lattice are compared for different lattice sizes in the physical region. The Parallel-Transported Multigrid algorithm (PTMG) turns out to be superior to the Conjugate-Gradient (CG) approach. As the lattice size L increases (together with the correlation length ξ) the PTMG becomes more and more efficient. On a 256×256 lattice with the bare quark mass mbare=0.0005 and ξ=20, the PTMG is at least ten times faster than the CG. It seems reasonable to expect similar results in four dimensions.
PROGRAMMING TOOLS FOR PARALLEL COMPUTERS
Authors: MORIARTY K. J. M. , TRAPPENBERG T.
Published: November 2004

Although software tools already have a place on serial and vector computers they are becoming increasingly important for parallel computing. Message passing libraries, parallel operating systems and high level parallel languages are the basic software tools necessary to implement a parallel processing program. These tools up to now have been specific to each parallel computer system and a short survey will be given. The aim of another class of software tools for parallel computers is to help in writing or rewriting application programs. Because automatic parallelization tools are not very successful, an interactive component has to be incorporated. We will concentrate here on the discussion of SPEFY, a parallel program development facility.
EFFICIENT K-SELECTION IN HYPERCUBE MULTIPROCESSORS
Authors: BERTHOMÉ PASCAL
Published: November 2004

This paper deals with the problem of finding the K smallest elements out of a totally ordered but non-sorted set of N elements. This problem, called K-selection, arises often in statistics, image processing and distributed computing. We propose two algorithms to solve this problem in hypercubes. Our first algorithm is asymptotically optimal when K = O(( log N)β), for any constant β. The second enlarges the range of optimality to K = N∊, ∊ < 1, using a recursive strategy. These are major improvements on previous results.
PRAS: PARALLEL ALIGNMENT OF SEQUENCES ALGORITHM
Authors: KULKARNI RAJENDRA , DATE SHASHANK , KULKARNI BHAVNA , KULKARNI URMILA , KOLASKAR A.S.
Published: November 2004

This paper presents an algorithm for multiple alignment of sequences of proteins and nucleic acids on loosely-coupled MIMD machines. An inherently parallel algorithm is devised and implemented on a transputer-based multiprocessor platform. The results indicate the possibility of scalable performance.
THE PARASUPERSYMMETRIC SPINNING PARTICLE AND TOPOLOGICAL GAUGE FIELDS
Authors: KORCHEMSKY G. P.
Published: November 2004

The first quantization of the D-dimensional relativistic spinning particle with the action invariant under reparametrizations and local worldline parasupersymmetric transformations is performed. The corresponding symmetry algebra is not of the Lie kind and is known as a polynomial algebra. It is found that the physical space of the massless particle is described by the strength tensors of Abelian antisymmetric gauge fields and topological gauge fields. In the special case D = 3 the Abelian Chern–Simons gauge field appears as a wave function of the particle. The generalizations to a massive parasupersymmetric spinning particle are presented.
W INFINITY AND STRING THEORY
Authors: SHEN X.
Published: November 2004

Some recent developments in the theory of W∞ are reviewed. Its relevance to lower-dimensional string theory is commented on.
A MORPHO-SYNTACTIC ANALYSIS BASED LEXICAL SUBSYSTEM
Authors: SENGUPTA P. , CHAUDHURI B.B.
Published: November 2004

A lexical subsystem that contains a morphological level parser is necessary for processing natural languages in general and inflectional languages in particular. Such a subsystem should be able to generate the surface form (i.e. as it appears in a natural sentence) of a word, given the sequence of morphemes constituting the word. Conversely, and more importantly, the subsystem should be able to parse a word into its constituent morphemes. A formalism which enables the lexicon writer to specify the lexicon of an inflectional language is discussed. The specifications are used to build up a lexical description in the form of a lexical database on one hand and a formulation of derivational morphology, called Augmented Finite State Automata (AFSA), on the other. A compact lexical representation has been achieved, where generation of the surface forms of a word, as well as parsing of a word is performed in a computationally attractive manner. The output produced as a result of parsing is suitable for input to the next stage of analysis in a Natural Language Processing (NLP) environment, which, in our case is based on a generalization of the Lexical Functional Grammar (LFG). The application of the formalism on inflectional Indian languages is considered, with Bengali, a modern Indian language, as a case study.
SYNCHRONIZATION OF CHAOS
Authors: ANISHCHENKO V. S. , VADIVASOVA T. E. , POSTNOV D. E. , SAFONOVA M. A.
Published: November 2004

This paper is devoted to the problem of synchronization of dynamical systems in chaotic oscillations regimes. The authors attempt to use the ideas of synchronization and its mechanisms on a certain class of chaotic oscillations. These are chaotic oscillations for which one can pick out basic frequencies in their power spectra.

The physical and computer experiments were carried out for the system of two coupled auto-oscillators. The experimental installation permitted one to realize both unidirectional coupling (external synchronization) and symmetrical coupling (mutual synchronization). An auto-oscillator with an inertial nonlinearity was chosen as a partial subsystem. It possesses a chaotic attractor of spiral type in its phase space. It is known that such chaotic oscillations have a distinguished peak in the power spectrum at the frequency f0 (basic frequency). In the experiments, one could make the basic frequencies of partial oscillators equal or different. The bifurcation diagrams on the plane of control parameters "detuning" and "coupling" were constructed and analyzed.

The results of investigations permit one to conclude that classical ideas of synchronization can be applied to chaotic systems of the mentioned type. Two mechanisms of chaos synchronization were established: 1) basic frequency locking and 2) basic frequency suppression. The bifurcational background of these mechanisms was created using numerical analysis on a computer. This allowed one to analyze the evolution of different oscillation characteristics under the influence of synchronization.
TWO TREE DRAWING CONVENTIONS
Authors: EADES PETER , LIN TAO , LIN XUEMIN
Published: November 2004

Rooted trees abound in computing and it is often necessary to draw them for visualization and documentation purposes. In the classical convention for tree drawing, the tree is drawn in a “level” fashion, with nodes (represented by boxes) at depth k lying on a horizontal line at a distance of k units below the root. The parent — child relationships are represented by lines between the boxes. Several algorithms have been developed for constructing a compact layout of a tree in the classical convention.

In this paper we investigate algorithms for drawing trees according to two new conventions. In the inclusion convention, nodes are represented by boxes, and the parent — child relationship is represented by inclusion of one box in another. The tip-over convention again represents nodes as boxes, and, like the classical convention, represents the parent — child relationship by lines between the boxes; however, we allow siblings to be arranged vertically rather than horizontally.

For many of the cases which arise in visualization of trees (for example, binary trees with textual information at the leaves) we present polynomial time algorithms. However, the general problem of finding minimum size layouts for either of the new conventions is shown to be NP-hard.
Heat Shock Protein 70 Confers Cardiovascular Protection During Endotoxemia via Inhibition of Nuclear Factor-κB Activation and Inducible Nitric Oxide Synthase Expression in the Rostral Ventrolateral Medulla
Authors: Chan Julie Y.H. , Ou Chen-Chun , Wang Ling-Lin , Chan Samuel H.H.
Published: November 2004

Background—

Overproduction of nitric oxide (NO) by inducible NO synthase (iNOS) in the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons are located, plays a pivotal role in the manifestation of fatal cardiovascular depression during endotoxemia. The iNOS gene is regulated transcriptionally by nuclear factor-κB (NF-κB) activation. The present study tested the hypothesis that heat shock protein 70 (HSP70) may confer protection against sepsis-induced circulatory fatality via inhibition of iNOS gene expression in the RVLM through prevention of NF-κB activation.

Methods and Results—

Adult male Sprague-Dawley rats subjected to a brief hyperthermic heat shock (42°C for 15 minutes) exhibited significant upregulation of HSP70 in the RVLM. Brief heat shock preconditioning also significantly suppressed iNOS mRNA or protein surge and alleviated hypotension, bradycardia, and reduction in neurogenic sympathetic vasomotor activity manifested during experimental endotoxemia induced by intravenous administration of
Escherichia coli
lipopolysaccharide. An increase in DNA binding activity and nuclear translocation of transcription factor NF-κB were detected during endotoxemia. Heat shock preconditioning significantly decreased DNA binding activity of NF-κB, which was reversed by microinjection of an
hsp
70 antisense oligonucleotide bilaterally into the RVLM. Heat shock preconditioning also blocked inhibitory κB (IκB) kinase activity or degradation of IκB in the RVLM during endotoxemia.

Conclusions—

We conclude that HSP70 confers protection against sepsis-related circulatory fatality via inhibition of iNOS gene expression in the RVLM through prevention of NF-κB activation in cellular processes that include prevention of IκB kinase activation and inhibition of IκBα degradation.
Chronic Lymphocytic Leukemia
Authors: Byrd John C. , Stilgenbauer Stephan , Flinn Ian W.
Published: November 2004

Chronic lymphocytic leukemia (CLL) is one of the most commonly diagnosed leukemias managed by practicing hematologists. For many years patients with CLL have been viewed as similar, with a long natural history and only marginally effective therapies that rarely yielded complete responses. Recently, several important observations related to the biologic significance of VH mutational status and associated ZAP-70 overexpression, disrupted p53 function, and chromosomal aberrations have led to the ability to identify patients at high risk for early disease progression and inferior survival. Concurrent with these investigations, several treatments including the nucleoside analogues, monoclonal antibodies rituximab and alemtuzumab have been introduced. Combination of these therapies in clinical trials has led to high complete and overall response rates when applied as initial therapy for symptomatic CLL. Thus, the complexity of initial risk stratification of CLL and treatment has increased significantly. Furthermore, when these initial therapies do not work, approach of the CLL patient with fludarabine-refractory disease can be quite challenging. This session will describe the natural history of a CLL patient with emphasis on important decision junctures at different time points in the disease.

In Section I, Dr. Stephan Stilgenbauer focuses on the discussion that occurs with CLL patients at their initial evaluation. This includes a review of the diagnostic criteria for CLL and prognostic factors utilized to predict the natural history of the disease. The later discussion of risk stratification focuses on molecular and genomic aberrations that predict rapid progression, poor response to therapy, and inferior survival. Ongoing and future efforts examining early intervention strategies in high risk CLL are reviewed.

In Section II, Drs. Ian Flinn and Jesus G. Berdeja focus on the discussion of CLL patients when symptomatic disease has developed. This includes an updated review of monotherapy trials with nucleoside analogs and recent trials that have combined these with monoclonal antibodies and/or alternative chemotherapy agents. Appropriate application of more aggressive therapies such as autologous and allogeneic immunotherapy and less aggressive treatments for appropriate CLL patient candidates are discussed.

In Section III, Dr. John Byrd focuses on the discussion that occurs with CLL patients whose disease is refractory to fludarabine. The application of genetic risk stratification in choosing therapy for this subset of patients is reviewed. Available data with conventional combination based therapies and monoclonal antibodies are discussed. Finally, alternative promising investigational therapies including new antibodies, kinase inhibitors (CDK, PDK1/AKT, PKC) and alternative targeted therapies (DNA methyltransferase inhibitors, histone deacetylase inhibitors, etc.) are reviewed with an emphasis on the most promising agents for this patient population.
Immunotherapeutic Approaches for Hematologic Malignancies
Authors: Caligiuri Michael A. , Velardi Andrea , Scheinberg David A. , Borrello Ivan M.
Published: November 2004

The immune system has two complementary arms: one is older and seemingly more primitive, called the innate immune system, found in both plants and animals. The second (already many millions of years old!) is the adaptive or antigen-specific immune system, limited to vertebrate animals. The human innate immune system has many cellular elements that include granulocytes, monocytes, macrophages, natural killer (NK) cells, mast cells, eosinophils, and basophils. Receptors for these cells are non-clonal, fixed in the genome, requiring no rearrangement, and recognize conserved molecular patterns that are specific to pathogens. The adaptive immune system (B cells and T cells) have receptors with great variation, able to recognize an almost an unlimited number of highly specific pathogens through rearrangement of receptor gene segments, and can also provide immunological memory so critical for vaccination. As the immune system has evolved to recognize non-self, malignant transformation of self can likely escape immune surveillance with relative ease. Contributors to this chapter are utilizing distinct components of either the innate or adaptive immune system that recognize non-self, in combination with what we know about differences between malignant and normal self, in an effort to develop novel and effective immunologic approaches against hematologic malignancies.

In Section I, Dr. Andrea Velardi reviews the benefits of NK cell alloreactivity in mismatched hematopoietic transplantation, provides updates on current clinical trials, and discusses further therapeutic perspectives emerging from murine bone marrow transplant models.

In Section II, Dr. David Scheinberg reviews novel leukemic antigens being targeted by humanized monoclonal antibodies as well as mechanisms by which antibody-mediated cytotoxicity occurs in vivo.

In Section III, Dr. Ivan Borrello reviews vaccine and adoptive T cell immunotherapy in the treatment of hematologic malignancies. Specifically, he discusses the various vaccine approaches used as well as strategies aimed at augmenting the tumor specificity of T cell therapies.
Waldenstrom’s Disease and cardiopulmonary bypass: a case report
Authors: Sweeting Claire A. , Kelleher Noel , Mahmood Nilofer , Unsworth-White Jonathan , Weatherall Mike , Webb Gerry
Published: November 2004

Waldenstrom’s Macroglobulinaemia (WM) is a rare haematological lymphoma that causes numerous haemo-static complications due to the elevated levels of immunoglobulin M (IgM) circulating in the blood. These complications, such as hyperviscosity syndrome, may be exacerbated by the physiological effects of cardiopulmonary bypass (CPB). In this case study, a 45-year-old male suffering from WM underwent an emergency aortic valve replacement, closure of an atrio-ventricular fistula and mitral valve repair. He was found to have an elevated blood viscosity, anaemia and hypervolaemia prior to surgery. These complications remained a problem during CPB, leading to a large circulating volume, but a low haemoglobin, requiring haemofiltration and blood transfusions whilst limiting any further rise in blood viscosity. The situation was further compounded by the presence of electrolyte disturbances. It was concluded that a careful balance between blood conservation techniques and temperature management was required to reduce hyperviscosity and anaemia, but maintain organ protection. In future, given more time, modern plasmapheresis techniques could be used for acute management of WM during CPB.
Prediction of peak oxygen uptake in patients fulfilling the 1994 CDC criteria for chronic fatigue syndrome
Authors: Nijs Jo , De Meirleir Kenny
Published: November 2004

Purpose: To establish an inexpensive, simple method of predicting peak oxygen uptake (VO2peak) in patients fulfilling the 1994 Centers for Disease Control and Prevention (CDC) criteria for chronic fatigue syndrome (CFS).

Design: A retrospective observational study.

Setting: An outpatient tertiary care chronic fatigue clinic.

Subjects: Two hundred and forty consecutive patients fulfilling the 1994 CDC criteria for CFS.

Interventions: Heart rate, metabolic and ventilatory parameters were measured continuously during a maximal exercise stress test on a bicycle ergometer. Using the equation peak oxygen uptake / 13.1 / peak workload / 284 (used by Mullis et al., Br J Sports Med1999; 33: 352 / 56), VO2peak was predicted from the peak workload of a maximal exercise capacity test. Pearson correlation coefficient and linear regression analysis were used to establish the most accurate way to predict VO2peak.

Results: Percentage error encountered when comparing actual measured Vo2peak with predicted value was 17.3% (9-10.0). A strong correlation between Vo2peak and peak workload was observed (r / 0.89, p< 0.001). A regression analysis established the relation as Vo2peak= 10.47 × peak workload +284.1, where Vo2peak is given in ml/min and peak workload in W (error in prediction = 11.09±9.5%).

Conclusions: Monitoring of the peak workload during a maximal, graded bicycle ergometric test suffices to predict the Vo2peak. When predicting Vo2peak the used operational definition for the diagnosis of CFS could be taken into account. Compared with the equation used by Mullis et al., peak workload is multiplied by 10.47 in order to predict peak oxygen uptake in CDC-defined CFS patients.
A randomized trial to evaluate an education programme for patients and carers after stroke
Authors: Smith Jane , Forster Anne , Young John
Published: November 2004

Objectives: To evaluate the effectiveness of an education programme for patients and carers recovering from stroke.

Design: Randomized controlled trial.

Subjects and setting: One hundred and seventy patients admitted to a stroke rehabilitation unit and 97 carers of these patients.

Interventions: The intervention group received a specifically designed stroke information manual and were invited to attend education meetings every two weeks with members of their multidisciplinary team. The control group received usual practice.

Measures: Primary outcome was knowledge of stroke and stroke services. Secondary outcomes were handicap (London Handicap Scale), physical function (Barthel Index), social function (Frenchay Activities Index), mood (Hospital Anxiety and Depression Scale) and satisfaction (Pound Scale). Carer mood was measured by the General Health Questionnaire-28.

Results: There was no statistical evidence for a treatment effect on knowledge but there were trends that favoured the intervention. The education programme was associated with a significantly greater reduction in patient anxiety score at both three months (p=0.034) and six months (p=0.021) and consequently fewer ‘cases’ (Hospital Anxiety and Depression Scale anxiety subscale score ≥ 11). There were no other significant statistical differences between the patient or carer groups for other outcomes, although there were trends in favour of the education programme.

Conclusion: An education programme delivered within a stroke unit did not result in improved knowledge about stroke and stroke services but there was a significant reduction in patient anxiety at six months post stroke onset.
Prismatic correction in patients affected by age-related macular degeneration
Authors: Parodi Maurizio Battaglia , Toto Lisa , Mastropasqua Leonardo , Depollo Marta , Ravalico Giuseppe
Published: November 2004

Objective: To evaluate by means of a controlled clinical trial the effectiveness and the tolerance of prismatic correction in improving visual function in patients affected by advanced bilateral age-related macular degeneration.

Setting: Department of Ophthalmology, Eye Clinic, University of Trieste.

Subjects and interventions: Each patient underwent an ophthalmologic examination, complete with distance visual acuity measurement using the Standard Early Treatment Diabetic Retinopathy Study chart. Patients were then randomly assigned to the treatment or control group. The treatment group received spectacles lenses with a prismatic correction of low power (5–7 prismatic dioptres) in the better eye.

Main measures: Visual acuity was measured at baseline and 1, 90, 180 and 360 days after prescription in both groups.

Results: The treatment group consisted of 14 patients, while the control group was of 14 patients. The prismatic correction was well tolerated in 85.7% of cases. Visual acuity in the treatment group improved mostly at three-month follow-up, with a slight further improvement at the sixand 12-month follow-ups, showing a statistically significant difference in comparison with the control group. No visual acuity improvement was registered in the control group.

Conclusion: Monolateral prismatic correction may be considered a viable means to improve visual function in patients affected by bilateral age-related macular degeneration at an advanced stage.
Book Reviews
Authors: Mooney James
Published: November 2004

Book reviewed in this article:

Die Anmut des Frauenleibes. Von Friedrich S. Krauss. Leipzig: Adolph Schumann

Ein Geniestreich. Volkstück in fünf Aufzügen oder neun Bildern. Von Milovan Gj. Gliŝiĉ. Deutsch von Friedrich S. Krauss. Mit echten serbischen Sang‐ und zigeunerischen Spielweisen von Vladimir R. Gjorgjević.

Künstlerblut! Ein Schauspiel in vier Aufzügen. Von Friedrich S. Krauss und Leo Norberg.
Book Reviews
Authors: MOONEY JAMES
Published: November 2004

Book reviewed in this article:

Der volksmund: Alte und neue beiträge zür Volksforschung, Herausgegeben von Dr. FRIEDRICH S. KRAUSS.
Book Reviews
Authors: Starr Frederick
Published: November 2004

Book reviewed in this article:

AFRICA: The Akamba of British East Africa; An Ethnological Monograph. Gerhard Lindblom.

AFRICA: Die Kpelle: ein Negerstamm in Liberia dargestellt auf der Grundlage von Eingeborenen‐Berichten. Mit zwei Nachträgen: Texte in der Golasprache und Kpelle‐Beiträge von H. Rohde
BOOK REVIEWS
Authors: Gladwin H. S. , Kelly Isabel
Published: November 2004

Book reviewed in this article:

A Method for Designation of Ruins in the Southwest;

The Use of Potsherds in an Archaeological Survey of the Southwest;

The Red‐on‐Buff Culture of the Gila Basin;

The Red‐on‐Buff Culture of the Papagueria;
BOOK REVIEW
Authors: Shepard Anna O.
Published: November 2004

Book reviewed in this article:

The Mogollon Culture of Southwestern New Mexico. E. W. Haury.

Some Southwestern Pottery Types, Series IV. E. W. Haury.
BOOK REVIEW
Authors: Spier Leslie
Published: November 2004

Book reviewed in this article:

MEXICO AND SOUTH AMERICA: The Comparative Ethnology of Northern Mexico Before 1750. RAlph L. Beals.

The Distribution of Aboriginal Tribes and Languages in Northwestern Mexico. Carl Sauer.
BOOK REVIEW
Authors: Steward Julian H.
Published: November 2004

Book reviewed in this article:

Mangaian Society. Te Rangi Hiroa (P. H. Buck).

The Legends of Maui and Tahaki. J. F. Stimson.

Outline of Hawaiian Physical Therapeutics. E. S. Craighill Handy, Mary Kawena Pukui, and Katherine Livermore.

Notes on the Ethnology of Pukapuka. Gordon MacGregor.
Book Reviews
Authors: Wingert Paul S.
Published: November 2004

Book reviewed in this article:

From Cave Painting to Comic Strip. Lancelot Hogben.

Profile Art. R. L. Mégroz.