bluuebunny/crossref_metadata_2025 huggingface dataset:
Trophic Linkage between Stream Centrarchids and Their Crayfish Prey
Authors: Rabeni Charles F.
Published: October 2009

Energetic links between smallmouth bass (Micropterus dolomieu) and rock bass (Ambloplites rupestris) and their crayfish foods were examined in an Ozark stream. A trophic level energy budget was developed by enumerating food habits for different age (size) fish, estimating annual production for both fish and crayfish, and using laboratory- and literature-derived bioenergetic and gross efficiency data. Both fishes began life feeding on small invertebrates (mayflies and chironomids) but within 3 mo switched to a diet of mainly crayfish and Cyprinidae. Total annual production of smallmouth bass was 0.262 g dry weight∙m−2∙yr−1 (6344 J) and rock bass 0.148 g∙m−2∙yr−1 (3607 J). Total annual production of crayfish was 4.15 g dry weight∙m−2∙yr−1 (55 736 J) for Orconectes luteus and 5.05 g∙m−2∙yr−1 (62 394 J) for O. punctimanus. Only about half of the crayfish production was available to fish, due to size-selective predation and behavioral traits of the prey. A predator–prey model suggested that nearly one third of total crayfish production during their vulnerable period was lost to centrarchids, and that half of the existing biomass was consumed. Fish are probably the major cause of mortality in crayfish and undoubtedly influence crayfish population dynamics and energy flow through the river system.
Particulate Organic Carbon Supply and Trophic Dynamics in a Mississippi Flood-Control Reservoir Dominated by Gizzard Shad (Dorosoma cepedianum)
Authors: Aumen Nicholas G. , Crist Cindy L. , Miller Dawn E. , Meals Keith O.
Published: October 2009

Sources of particulate organic carbon (POC) and trophic–dynamic relationships were studied in a reservoir with low sportfish populations. Fish community structure and POC input from tributaries, phytoplankton primary production, and vascular vegetation on mudflats were estimated. Gizzard shad (Dorosoma cepedianum) averaged 39.8% of the total fish biomass in 1988, and as much as 94% of the total forage fish biomass was too large to serve as prey for most predators. Phytoplankton primary productivity averaged 1182 mg C∙m−2∙d−1in 1987 and 1988, contributed 33.57 Gg POC∙yr−1to the reservoir, and apparently was phosphate limited. POC inflow from tributaries contributed 60.00 Gg∙yr−1with 79% of POC <75 μm in size. Winter and spring stormflow was responsible for 92% of the total POC transported. Considering POC size fractions available to gizzard shad, POC input from tributaries, phytoplankton, and mudflats contributed 21, 54, and 25% of the total POC input, respectively. The trophic–dynamic analysis indicated that phytoplankton POC was adequate to support the reservoir fish community. A more efficient transfer of carbon in the food web might be accomplished by stocking with a smaller forage fish, such as threadfin shad (Dorosoma petenense), which are not common in the reservoir.
MEMORY EFFECT IN HOMOGENIZATION OF A VISCOELASTIC KELVIN–VOIGT MODEL WITH TIME-DEPENDENT COEFFICIENTS
Authors: ABDESSAMAD ZOUHAIR , KOSTIN ILYA , PANASENKO GRIGORY , SMYSHLYAEV VALERY P.
Published: October 2009

This paper is motivated by modeling the procedure of formation of a composite material constituted of solid fibers and of a solidifying matrix. The solidification process for the matrix depends on the temperature and on the reticulation rate which thereby influence the mechanical properties of the matrix. The mechanical properties are described by a viscoelastic medium equation of Kelvin–Voigt type with rapidly oscillating periodic coefficients depending on the temperature and the reticulation rate. That is modeled as an initial boundary value problem with time-dependent elasticity and viscosity tensors to account for the solidification, and the mechanical and/or thermal forcing. First we prove the existence and uniqueness of the solution for the problem and obtain a priori estimates. Then we derive the homogenized problem, characterize its coefficients including explicit memory terms, and prove that it admits a unique solution. Finally, we prove error bounds for the asymptotic solution, and establish some related regularity properties of the homogenized solution.
INFLUENCE OF OBJECTIVE FUNCTIONS IN STRUCTURAL DAMAGE IDENTIFICATION USING REFINED AND SIMPLE MODELS
Authors: PERERA RICARDO , FANG SHENG-EN
Published: October 2009

The most usual approach for solving damage identification problems is the use of the finite element (FE) model updating method. To apply the method, a minimization of an objective function measuring the fit between measured and model predicted data is performed. Then, the success of the procedure depends strongly on the accuracy of the FE model and the choice of a suitable objective function. Although detailed FE models provide an accurate means for calculating the dynamic response of the structure, their size and complexity involve a large number of parameters to be updated and a high computational cost. In order to shorten the computational time, more simplified and practical models able to model the global dynamic response of the structure accurately would be desirable. Furthermore, working with several objective functions instead of only one would increase the robustness and performance of the procedure. In this paper, a multi-objective simple beam model is proposed and compared with a more refined model based on plane elements. Furthermore, in the multi-objective framework, different combinations of objective functions are studied. The reliability and effectiveness of the proposed model has been evaluated in a damage detection problem of a reinforced concrete frame experimentally tested under different levels of damage.
A HIGH-ORDER FINITE ELEMENT FORMULATION FOR VIBRATION ANALYSIS OF BEAM-TYPE STRUCTURES
Authors: WEN Y. , ZENG Q. Y.
Published: October 2009

A high-order finite element model is presented to perform the vibration analysis of beams. The equations of motion are formulated by applying the principle of total potential energy in elastic dynamic system and the "set-in-right-position" rule for the construction of system matrices first proposed by the author. The primary advantage of the principle and rule lies in its simplicity and efficiency in solving the modeling problem of complex dynamic system. The requirement of strain continuity has certainly not being met at element interfaces with the use of conventional cubic Hermitian formulation. Hence, it is difficult to predict the dynamic responses of beams accurately. In order to overcome this problem, a beam element with simple higher-order interpolation function is chosen as the analysis model. Although the number of nodal degrees of freedom is increased herein, usually a coarse mesh will suffice. The present formulation is able to provide results of high accuracy with low computational effort. For the purpose of illustration, the dynamic characteristics analysis and dynamic response analysis are carried out on beam models. The solutions obtained for all the examples are in good agreement with the exact solutions found by fundamental theory of vibration.
USE OF MODAL FLEXIBILITY AND NORMALIZED MODAL DIFFERENCE FOR VIBRATION MODE SHAPE EXPANSION
Authors: REN WEI-XIN , JAISHI BIJAYA
Published: October 2009

Proposed herein are two possible ways for mode shape expansion for future use. The first method minimizes the modal flexibility error between the experimental and analytical mode shapes corresponding to the measured degrees of freedom (DOFs) to determine the multiplication matrix. In the second method, Normalized Modal Difference (NMD) is used to calculate the multiplication matrix using the analytical DOFs corresponding to the measured DOFs. This matrix is then used to expand the measured mode shape to unmeasured DOFs. A simulated simply supported beam is used to demonstrate the performance of the methods. These methods are then compared with two most promising existing methods, namely the Kidder dynamic expansion and the modal expansion methods. It is observed that the performance of the modal flexibility method is comparable with existing methods. NMD also have the potential to expand the mode shapes though it is seen to be more sensitive to the distribution of error between finite element method and actual test data.
SHARP BOUNDS FOR TRIGONOMETRIC POLYNOMIALS IN TWO VARIABLES
Authors: ALZER HORST , SHI XIQUAN
Published: October 2009

Let n ≥ 1, x, y ∈ (0, π), and [Formula: see text] and [Formula: see text] In 1932, Koschmieder proved that Fn(x,y) > 0. We present the following inequalities: [Formula: see text] and [Formula: see text] All bounds are best possible.
Growth and variation in the non-marine lamellibranch fauna above the Sand Rock Mine of the Lancashire Millstone Grit
Authors: Eagar Richard Michael Cardwell
Published: October 2009

Shells from a recently discovered band of non-marine lamellibranchs above the Sand Rock Mine (near the top of the Millstone Grit Series) west of Wigan have been statistically investigated at four localities. The dominant fauna,Carbonicola exporre tagar and variants, is systematically described and the variation analysed. The affinity of this fauna appear to lie with Carbonicolidae characterizing lower horizons in the Namurian, whereas a second group of shells, much less commonly represented in the band, shows similarity with the succeeding faunas ofAnthraconaia bellula(Bolton) andCarbonicola fallaxWright.

The shells range in length between 3 and 49 mm. Studies in the growth of both groups include the measurement of early growth-lines in the larger individuals and reveal considerable changes in the proportions of the shell. For the mean relative growth of communities evidence points to a linear relationship between the logarithms of shell height and length. This cannot yet be fully defined.

Petrological differences in the shell-bearing stratum have been investigated by Professor K. C. Dunham. It is shown, with the further support of chemical analysis, that a progressive decrease in the percentage of carbonaceous matter in the fossiliferous shale is accompanied by increase in the thickness of the band, decrease in the number of shells it contains per unit thickness, decrease in the mean size of the shells and a slight change in their relative growth-rates with respect to height and length. The latter two points indicate stunting of the fauna. The first three changes are considered to be the result of increased sedimentation.

Evidence is submitted for considering theC. exporrectafaunas to have been invaded by those of the second shell group. Detailed collecting at Upholland Station cutting reveals similarities in the succession of the latter faunas to that characterizing the base of sedimentary cycles in the Soft Bed—Bassy Mine succession of the lowerlenisulcataZone. Differences in the two horizons are discussed. No internal features of the shell are revealed in the second group, but numerous cases of perfect gradation betweenCarbonicola-like andAnthraconaia-like forms confirm previous observation in the lowerlenisulcataZone. The evolution of certain species ofCarbonicolafrom a group in which the generaCarbonicolaandAnthraconaiawere apparently not yet distinct is briefly discussed.
Organizing functional code for parallel execution or, foldl and foldr considered slightly harmful
Authors: Steele Guy L.
Published: October 2009

Alan Perlis, inverting OscarWilde's famous quip about cynics, once suggested, decades ago, that a Lisp programmer is one who knows the value of everything and the cost of nothing. Now that the conference on Lisp and Functional Programming has become ICFP, some may think that OCaml and Haskell programmers have inherited this (now undeserved) epigram.

I do believe that as multicore processors are becoming prominent, and soon ubiquitous, it behooves all programmers to rethink their programming style, strategies, and tactics, so that their code may have excellent performance. For the last six years I have been part of a team working on a programming language, Fortress, that has borrowed ideas not only from Fortran, not only from Java, not only from Algol and Alphard and CLU, not only from MADCAP and MODCAP and MIRFAC and the Klerer-May system-but also from Haskell, and I would like to repay the favor.

In this talk I will discuss three ideas (none original with me) that I have found to be especially powerful in organizing Fortress programs so that they may be executed equally effectively either sequentially or in parallel: user-defined associative operators (and, more generally, user-defined monoids); conjugate transforms of data; and monoid-caching trees (as described, for example, by Hinze and Paterson). I will exhibit pleasant little code examples (some original with me) that make use of these ideas.
Lambda, the ultimate TA
Authors: Pierce Benjamin C.
Published: October 2009

Ambitious experiments using proof assistants for programming language research and teaching are all the rage. In this talk, I'll report on one now underway at the University of Pennsylvania and several other sites: a one-semester graduate course in the theory of programming languages presented entirely - every lecture, every homework assignment - in Coq. I'll try to give a sense of what the course is like for both instructors and students, describe some of the most interesting challenges in developing it, and explain why I now believe such machine-assisted courses are the way of the future.
Commutative monads, diagrams and knots
Authors: Piponi Dan P.
Published: October 2009

There is certain diverse class of diagram that is found in a variety of branches of mathematics and which all share this property: there is a common scheme for translating all of these diagrams into useful functional code. These diagrams include Bayesian networks, quantum computer circuits [1], trace diagrams for multilinear algebra [2], Feynman diagrams and even knot diagrams [3]. I will show how a common thread lying behind these diagrams is the presence of a commutative monad and I will show how we can use this fact to translate these diagrams directly into Haskell code making use of do-notation for monads. I will also show a number of examples of such translated code at work and use it to solve problems ranging from Bayesian inference to the topological problem of untangling tangled strings. Along the way I hope to give a little insight into the subjects mentioned above and illustrate how a functional programming language can be a valuable tool in mathematical research and experimentation.
Causal commutative arrows and their optimization
Authors: Liu Hai , Cheng Eric , Hudak Paul
Published: October 2009

Arrows are a popular form of abstract computation. Being more general than monads, they are more broadly applicable, and in particular are a good abstraction for signal processing and dataflow computations. Most notably, arrows form the basis for a domain specific language called
Yampa
, which has been used in a variety of concrete applications, including animation, robotics, sound synthesis, control systems, and graphical user interfaces. Our primary interest is in better understanding the class of abstract computations captured by Yampa. Unfortunately, arrows are not concrete enough to do this with precision. To remedy this situation we introduce the concept of
commutative arrows
that capture a kind of non-interference property of concurrent computations. We also add an
init
operator, and identify a crucial law that captures the causal nature of arrow effects. We call the resulting computational model
causal commutative arrows
. To study this class of computations in more detail, we define an extension to the simply typed lambda calculus called
causal commutative arrows
(CCA), and study its properties. Our key contribution is the identification of a normal form for CCA called
causal commutative normal form
(CCNF). By defining a normalization procedure we have developed an optimization strategy that yields dramatic improvements in performance over conventional implementations of arrows. We have implemented this technique in Haskell, and conducted benchmarks that validate the effectiveness of our approach. When combined with stream fusion, the overall methodology can result in speed-ups of greater than two orders of magnitude.
Experience report
Authors: Newton Ryan R. , Ko Teresa
Published: October 2009

This paper presents our experience using a domain-specific functional language, WaveScript, to build embedded sensing applications used in scientific research. We focus on a recent computervision application for detecting birds in their natural environment. The application was ported from a prototype in C++. In reimplementing the application, we gained a much cleaner factoring of its functionality (through higher-order functions and better interfaces to libraries) and a near-linear parallel speed-up with no additional effort. These benefits are offset by one substantial downside: the lack of familiarity with the language of the original vision researchers, who understandably tried to use the language in the familiar way they use C++ and thus ran into various problems.
Experience report
Authors: Klein Gerwin , Derrin Philip , Elphinstone Kevin
Published: October 2009

We report on our experience using Haskell as an executable specification language in the formal verification of the seL4 microkernel. The verification connects an abstract operational specification in the theorem prover Isabelle/HOL to a C implementation of the microkernel. We describe how this project differs from other efforts, and examine the effect of using Haskell in a large-scale formal verification. The kernel comprises 8,700 lines of C code; the verification more than 150,000 lines of proof script.
Finding race conditions in Erlang with QuickCheck and PULSE
Authors: Claessen Koen , Palka Michal , Smallbone Nicholas , Hughes John , Svensson Hans , Arts Thomas , Wiger Ulf
Published: October 2009

We address the problem of testing and debugging concurrent, distributed Erlang applications. In concurrent programs, race conditions are a common class of bugs and are very hard to find in practice. Traditional unit testing is normally unable to help finding all race conditions, because their occurrence depends so much on timing. Therefore, race conditions are often found during system testing, where due to the vast amount of code under test, it is often hard to diagnose the error resulting from race conditions. We present three tools (QuickCheck, PULSE, and a visualizer) that in combination can be used to test and debug concurrent programs in unit testing with a much better possibility of detecting race conditions. We evaluate our method on an industrial concurrent case study and illustrate how we find and analyze the race conditions.
Beautiful differentiation
Authors: Elliott Conal M.
Published: October 2009

Automatic differentiation (AD) is a precise, efficient, and convenient method for computing derivatives of functions. Its forward-mode implementation can be quite simple even when extended to compute all of the higher-order derivatives as well. The higher-dimensional case has also been tackled, though with extra complexity. This paper develops an implementation of higher-dimensional, higher-order, forward-mode AD in the extremely general and elegant setting of
calculus on manifolds
and derives that implementation from a simple and precise specification. In order to motivate and discover the implementation, the paper poses the question "What does AD mean, independently of implementation?" An answer arises in the form of
naturality
of sampling a function and its derivative. Automatic differentiation flows out of this naturality condition, together with the chain rule. Graduating from first-order to higher-order AD corresponds to sampling all derivatives instead of just one. Next, the setting is expanded to arbitrary vector spaces, in which derivative values are linear maps. The specification of AD adapts to this elegant and very general setting, which even
simplifies
the development.
Generic programming with fixed points for mutually recursive datatypes
Authors: Yakushev Alexey Rodriguez , Holdermans Stefan , Löh Andres , Jeuring Johan
Published: October 2009

Many datatype-generic functions need access to the recursive positions in the structure of the datatype, and therefore adopt a fixed point view on datatypes. Examples include variants of fold that traverse the data following the recursive structure, or the Zipper data structure that enables navigation along the recursive positions. However, Hindley-Milner-inspired type systems with algebraic datatypes make it difficult to express fixed points for anything but regular datatypes. Many real-life examples such as abstract syntax trees are in fact systems of mutually recursive datatypes and therefore excluded. Using Haskell's GADTs and type families, we describe a technique that allows a fixed-point view for systems of mutually recursive datatypes. We demonstrate that our approach is widely applicable by giving several examples of generic functions for this view, most prominently the Zipper.
Control-flow analysis of function calls and returns by abstract interpretation
Authors: Midtgaard Jan , Jensen Thomas P.
Published: October 2009

We derive a control-flow analysis that approximates the interprocedural control-flow of both function calls and returns in the presence of first-class functions and tail-call optimization. In addition to an abstract environment, our analysis computes for each expression an abstract control stack, effectively approximating where function calls return across optimized tail calls. The analysis is systematically calculated by abstract interpretation of the stack-based CaEK abstract machine of Flanagan et al. using a series of Galois connections. Abstract interpretation provides a unifying setting in which we 1) prove the analysis equivalent to the composition of a continuation-passing style (CPS) transformation followed by an abstract interpretation of a stack-less CPS machine, and 2) extract an equivalent constraint-based formulation, thereby providing a rational reconstruction of a constraint-based control-flow analysis from abstract interpretation principles.
Experience report
Authors: Balat Vincent , Vouillon Jérôme , Yakobowski Boris
Published: October 2009

The evolution of Web sites towards very dynamic applications makes it necessary to reconsider current Web programming technologies. We believe that Web development would benefit greatly from more abstract paradigms and that a more semantical approach would result in huge gains in expressiveness. In particular, functional programming provides a really elegant solution to some important Web interaction problems, but few frameworks take advantage of it.

The Ocsigen project is an attempt to provide global solutions to these needs. We present our experience in designing this general framework for Web programming, written in Objective Caml. It provides a fully featured Web server and a framework for programming Web applications, with the aim of improving expressiveness and safety. This is done by taking advantage of functional programming and static typing as much as possible.
Implementing first-class polymorphic delimited continuations by a type-directed selective CPS-transform
Authors: Rompf Tiark , Maier Ingo , Odersky Martin
Published: October 2009

We describe the implementation of first-class polymorphic delimited continuations in the programming language Scala. We use Scala's pluggable typing architecture to implement a simple type and effect system, which discriminates expressions with control effects from those without and accurately tracks answer type modification incurred by control effects. To tackle the problem of implementing first-class continuations under the adverse conditions brought upon by the Java VM, we employ a selective CPS transform, which is driven entirely by effect-annotated types and leaves pure code in direct style. Benchmarks indicate that this high-level approach performs competitively.
Complete and decidable type inference for GADTs
Authors: Schrijvers Tom , Peyton Jones Simon , Sulzmann Martin , Vytiniotis Dimitrios
Published: October 2009

GADTs have proven to be an invaluable language extension, for ensuring data invariants and program correctness among others. Unfortunately, they pose a tough problem for type inference: we lose the principal-type property, which is necessary for modular type inference.

We present a novel and simplified type inference approach for local type assumptions from GADT pattern matches. Our approach is complete and decidable, while more liberal than previous such approaches.
An Interview with Chris Gunderson
Authors: Denning Peter
Published: October 2009

The increasing number of cyber attacks on military networks and servers has raised the question of what the global defense community is doing to safeguard military systems and protect the larger global Internet. Ubiquity's editor interviewed Chris Gunderson, who served in the U.S. Navy from 1973 to 2004 and became an expert in "network centric" warfare, on this question and in particular on how military philosophy must change to adapt to the rise of information networks.
Maladaptation of critical cellular functions in asthma: bioinformatic analysis
Authors: Agrawal Anurag , Sinha Anirban , Ahmad Tanveer , Aich Jyotirmoi , Singh Priyanka , Sharma Abhay , Ghosh Balaram
Published: October 2009

Small maladaptations in cellular response to environmental stressors may underlie diseases like asthma. However, genomewide transcriptional profile comparisons between case and controls only highlight the quantitatively largest changes. Critical cellular homeostatic pathways may be upregulated modestly during normal adaptation to stress but insufficiently during disease. To discover such pathways in asthma, we utilized public information on differential response of primary bronchial epithelial cells from asthmatic or normal subjects to stressors like ozone and viral infections. Genes that were upregulated by stressor conditions in normal cells but were relatively downregulated in cells from asthmatic subjects were selected for further analysis. Either a stringent selection based on quantitative criterion or a nonstringent selection followed by network-based analysis was used. At the individual gene level, decay accelerating factor-1 (DAF-1, CD55) was identified and selected for validation. In a mouse model of allergic airway inflammation (AAI) resembling asthma, protein expression of CD55 was reduced compared with normal mice and returned to normal upon resolution of the allergic response. This was consistent with our finding of relative downregulation of CD55 in asthmatic compared with normal subjects. Interestingly, at a network level, the results pointed to possible abnormalities in the inositol signaling pathway, a critical cell signaling mechanism. In the mouse model of AAI, we found downregulation of inositol polyphosphate 4 phosphatase A (INPP4A), a critical member of the inositol signaling pathway. This and previous genetic evidence supports a role for inositol signaling abnormalities in asthma. In summary, logic-gated hypothesis-free exploration of published data sets may be valuable in discovery of novel disease-associated pathways.
The Changing Presentation of Choledochal Cyst Disease: An Incidental Diagnosis
Authors: Dhupar Rajeev , Gulack Brian , Geller David A. , Marsh J. Wallis , Gamblin T. Clark
Published: October 2009

Background. Choledochal cysts are uncommon biliary lesions. Due to the evolution of imaging and laparoscopic surgery, we sought to describe our last 3 years experience with the presentation and management of choledochal cysts in adults. Methods. A retrospective review of a prospectively established database of adults who were managed for primary choledochal cyst disease between 2005 and 2008 was performed. Results. Between 8/2005 and 8/2008, 14 adults were managed for primary choledochal cyst disease. The average age was 41 years (range 17–86) and 79% were female. Presentations included biliary sepsis (3), pancreatitis (2), abdominal pain (3), or painless jaundice (1). Three patients had the cyst found during laparoscopic cholecystectomy, and two had an incidental finding after CT scan for an unrelated issue. The length of stay for those who had the cyst removed was 7.8 days (range 5–11). There were no operative or post-operative complications. Conclusions. Over the last 3 years 36% of our patients with choledochal cysts presented after incidental finding, either during a laparoscopic operation or after a CT scan for an unrelated problem. Increasing utilization of laparoscopy and CT scan for abdominal complaints has lead to a change in the pattern of presentation.
Analysis of CNT Bundle and Its Comparison with Copper Interconnect for CMOS and CNFET Drivers
Authors: Kureshi Abdul Kadir , Hasan Mohd.
Published: October 2009

In nanoscale regime as the CMOS process technology continues to scale, the standard copper (Cu) interconnect will become a major hurdle for onchip communication due to high resistivity and electromigration. This paper presents the comprehensive evaluation of mixed CNT bundle interconnects and investigates their prospects as a low power high‐speed interconnect for future nanoscale‐integrated circuits. The performance of mixed CNT bundle interconnect is examined with carbon nanotube field effect transistor (CNFET) as a driver and compared with the traditional interconnect, that is, CMOS driver on Cu interconnect. All HSPICE simulations are carried out at operating frequency of 1 GHz and it is found that mixed CNT bundle interconnects with CNFET as the driver can potentially provide a substantial delay reduction over traditional interconnects implemented at 32 nm process technology. Similarly, the CNFET driver with mixed CNT bundle as interconnect is more energy efficient than the traditional interconnect at all supply voltages (VDD) from 0.9 V to 0.3 V.
On Generalized Implicit Vector Equilibrium Problems in Topological Ordered Spaces
Authors: Luo Qun
Published: October 2009

We discuss three classes of generalized implicit vector equilibrium problems in topological ordered spaces. Under some conditions, we prove three new existence theorems of solutions for the generalized implicit vector equilibrium problems in topological ordered spaces by using the Fan-Browder fixed point theorem.
Self‐Assembly of Cluster‐Based Nanoscopic Supramolecules into One‐Dimensional Coordination Polymers
Authors: Zhang Jian-Jun , Gamboa Sergio Aarón , Davis Barry Julian , Lachgar Abdessadek
Published: October 2009

Octahedral metal clusters , (Mn(Salen)) + (or (Mn(7‐MeSalen)) +) (Salen = N, N′‐ethylene‐bis‐(salicylidene)iminate) and ditopic organic linkers (4, 4′‐bpe (trans‐1, 2‐bis(4‐pyridyl)‐ethylene) or 4, 4′‐dpyo (4, 4′‐dipyridyl N, N′‐dioxide)) self‐assemble to form three cluster‐based 1D coordination polymers: {(4, 4′‐dpyo) [(Mn(Salen))2(Nb6Cl12(CN)6)] } · 2MeOH
(1), 1.5MeCN · 8H2O
(2), and
[(Mn(Salen))2(Nb6Cl12(CN)6)]} · 16H2O
(3). Single crystal X‐ray diffraction analyses show that the frameworks of the three coordination polymers are built of heterotrimeric and/or heteropentameric supramolecular species linked by ditopic organic ligands. The framework of 1 consists of anionic chains built of heterotrimeric dianions (T) linked by 4, 4′‐dpyo. The chains run along two directions ([0 2 −2] and [0 3 3]) leading to the formation of channels along the crystallographic (a) direction where the cations [Mn(Salen)(S)2]+ and solvent molecules are located. Also, 2 was reported earlier, it possesses a neutral 1D chain built of neutral heterpentameric supramolecules: [(Mn(7‐MeSalen))2(Mn(7‐MeSalen)(S))2(Nb6Cl12(CN)6)] (P) linked by 4, 4′‐bpe ligands. Hydrogen bonds between non‐bridging cyanide ligands and coordinated solvent molecules connect the chains into 2D hydrogen‐bonded frameworks. Finally, 3 features an anionic chain, built of alternating heterotrimers and heteropentamers [(Mn(Salen)(S))2(Mn(Salen))2(Nb6Cl12(CN)6)] linked by the organic spacer 4, 4′‐bpe. The anionic charge is compensated by the in situe‐assembled dimers. Magnetic measurements reveal that the Mn(III) ions are well isolated and only weak magnetic interactions are observed. The thermal stability of the three compounds was investigated.
Multiplicity Results for p‐Laplacian with Critical Nonlinearity of Concave‐Convex Type and Sign‐Changing Weight Functions
Authors: Hsu Tsing-San
Published: October 2009

The multiple results of positive solutions for the following quasilinear
elliptic equation: in Ω, u = 0 on ∂Ω, are established. Here, 0 ∈ Ω is a bounded smooth domain in ℝN, Δp denotes the p‐Laplacian operator, 1 ≤ q < p < N, p∗ = Np/(N − p), λ is a positive real parameter, and f, g are continuous functions on which are somewhere positive but which may change sign on Ω. The study is based on the extraction of Palais‐Smale sequences in the Nehari manifold.
On a Generalized Discrete Ratio‐Dependent Predator‐Prey System
Authors: Fan Yong-Hong , Wang Lin-Lin
Published: October 2009

Verifiable criteria are established for the permanence and existence of positive periodic solutions of a delayed discrete predator‐prey model with monotonic functional response. It is shown that the conditions that ensure the permanence of this system are similar
to those of its corresponding continuous system. And the investigations generalize some well‐known results. In particular, a more acceptant method is given to study the bounded discrete systems rather than the comparison theorem.
Necessary and Sufficient Conditions for the Existence of a Hermitian Positive Definite Solution of a Type of Nonlinear Matrix Equations
Authors: Zhao Wenling , Li Hongkui , Liu Xueting , Xu Fuyi
Published: October 2009

We study the Hermitian positive definite solutions of the nonlinear matrix equationX+A∗X−2A=I, whereAis ann×nnonsingular matrix. Some necessary and sufficient conditions for the existence of a Hermitian positive definite solution of this equation are given. However, based on the necessary and sufficient conditions, some properties and the equivalent equations ofX+A∗X−2A=Iare presented while the matrix equation has a Hermitian positive definite solution.
Child Skeletal Fluorosis from Indoor Burning of Coal in Southwestern China
Authors: Qin Xianghui , Wang Shouying , Yu Maojuan , Zhang Lei , Li Xinhua , Zuo Zhen , Zhang Xiuhui , Wang Lihua
Published: October 2009

Objectives. We assess the prevalence and pathogenic stage of skeletal fluorosis among children and adolescents residing in a severe coal-burning endemic fluorosis area of southwest China.Methods. We used a cross-sectional design. A total of 1,616 students aged between 7 and 16 years in Zhijin County, Guizhou, China in late 2004 were selected via a cluster sampling of all 9-year compulsory education schools to complete the study questionnaire. Any student lived in a household that burned coal, used an open-burning stove, or baked foodstuffs over a coal stove was deemed high-risk for skeletal fluorosis. About 23% (370) of students (188 boys, 182 girls) were identified as high-risk and further examined by X-ray.Results. One-third of the 370 high-risk participants were diagnosed with skeletal fluorosis. Overall prevalence of child skeletal fluorosis due to indoor burning of coal was 7.5%. Children aged 12–16 years were significantly more likely to be diagnosed with skeletal fluorosis than children aged 7–11 years (OR = 1.84, 95% CI: 1.17–2.90; = .0082). Four types of skeletal fluorosis were identified: constrictive (60.7%), raritas (15.6%), mixed (16.4%), and soft (7.4%). Most diagnosed cases (91%) were mild or moderate in severity. In addition, about 97% of 370 high-risk children were identified with dental fluorosis. Dental fluorosis was highly correlated with skeletal fluorosis in this study.Conclusions. Skeletal fluorosis among children may contribute to poor health and reduced productivity when they reach adulthood. Further efforts to reduce fluoride exposure among children in southwestern of China where coal is burned indoors are desperately needed.
Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin
Authors: Li Xiaoping , Hunt Katharine L. C. , Wang Fei , Abel Martin , Frommhold Lothar
Published: October 2009

Collision-induced absorption by hydrogen and helium in the stellar atmospheres of cool white dwarfs causes the emission spectra to differ significantly from the expected blackbody spectra of the cores. For detailed modeling of radiative processes at temperatures up to 7000 K, the existing H2–H2 induced dipole and potential energy surfaces of high quality must be supplemented by calculations with the H2 bonds stretched or compressed far from the equilibrium length. In this work, we describe new dipole and energy surfaces, based on more than 20 000 ab initio calculations for H2–H2. Our results agree well with previous ab initio work (where those data exist); the calculated rototranslational absorption spectrum at 297.5 K matches experiment similarly well. We further report the calculated absorption spectra of H2–H2 for frequencies from the far infrared to 20 000 cm−1, at temperatures of 600 K, 1000 K, and 2000 K, for which there are no experimental data.
The Potential Value of Near Patient Platelet Function Testing in PCI: Randomised Comparison of 600 mg versus 900 mg Clopidogrel Loading Doses
Authors: Hobson Alex R. , Qureshi Zeshan , Banks Phil , Curzen Nicholas
Published: October 2009

Whilst poor response to clopidogrel is associated with adverse outcomes uncertainty exists as to how (a) response should be assessed and (b) poor responders managed. We utilised VerifyNow P2Y12 and short Thrombelastography (TEG) to assess 900 mg doses in (i) initial poor responders to 600 mg and (ii) in a randomised comparison with 600 mg.
Blood was taken before and six hours post clopidogrel in (i) 30 volunteers receiving 600 mg (poor responders received 900 mg > two weeks later) and (ii) 60 patients randomized 1 : 1 to 600 mg or 900 mg doses. Poor response was defined as TEG %Clotting Inhibition (%CIn) or VerifyNow Platelet Response Unit (PRU) reduction 30%. (i) Poor responders to 600 mg had greater PRU reduction (45.0 versus 20.1%, P = 0.03) and greater %CIn (22.9 versus %, P = 0.01) after 900 mg but (ii) there were no significant differences between the patient groups. Near-patient assessment of response to clopidogrel is feasible and clinically useful. Whilst ineffective on a population basis 900 mg doses increase the effect of clopidogrel in initial poor responders.
Electroanatomic Mapping and Radiofrequency Ablation of Porcine Left Atria and Atrioventricular Nodes Using Magnetic Resonance Catheter Tracking
Authors: Schmidt Ehud J. , Mallozzi Richard P. , Thiagalingam Aravinda , Holmvang Godtfred , d'Avila Andre , Guhde Renee , Darrow Robert , Slavin Glenn S. , Fung Maggie M. , Dando Jeremy , Foley Lori , Dumoulin Charles L. , Reddy Vivek Y.
Published: October 2009

Background—

The MRI-compatible electrophysiology system previously used for MR-guided left ventricular electroanatomic mapping was enhanced with improved MR tracking, an MR-compatible radiofrequency ablation system and higher-resolution imaging sequences to enable mapping, ablation, and ablation monitoring in smaller cardiac structures. MR-tracked navigation was performed to the left atrium (LA) and atrioventricular (AV) node, followed by LA electroanatomic mapping and radiofrequency ablation of the pulmonary veins (PVs) and AV node.

Methods and Results—

One ventricular ablation, 7 PV ablations, 3 LA mappings, and 3 AV node ablations were conducted. Three MRI-compatible devices (ablation/mapping catheter, torqueable sheath, stimulation/pacing catheter) were used, each with 4 to 5 tracking microcoils. Transseptal puncture was performed under x-ray, with all other procedural steps performed in the MRI. Preacquired MRI roadmaps served for real-time catheter navigation. Simultaneous tracking of 3 devices was performed at 13 frames per second. LA mapping and PV radiofrequency ablation were performed using tracked ablation catheters and sheaths. Ablation points were registered and verified after ablation using 3D myocardial delayed enhancement and postmortem gross tissue examination. Complete LA electroanatomic mapping was achieved in 3 of 3 pigs, Right inferior PV circumferential ablation was achieved in 3 of 7 pigs, with incomplete isolation caused by limited catheter deflection. During AV node ablation, ventricular pacing was performed, 3 devices were simultaneously tracked, and intracardiac ECGs were displayed. 3D myocardial delayed enhancement visualized node injury 2 minutes after ablation. AV node block succeeded in 2 of 3 pigs, with 1 temporary block.

Conclusions—

LA mapping, PV radiofrequency ablation, and AV node ablation were demonstrated under MRI guidance. Intraprocedural 3D myocardial delayed enhancement assessed lesion positional accuracy and dimensions.
Relation Between Alkaline Phosphatase, Serum Phosphate, and All-Cause or Cardiovascular Mortality
Authors: Tonelli Marcello , Curhan Gary , Pfeffer Marc , Sacks Frank , Thadhani Ravi , Melamed Michal L. , Wiebe Natasha , Muntner Paul
Published: October 2009

Background—

Higher levels of serum alkaline phosphatase (AlkP) are associated with excess mortality in dialysis patients, but whether AlkP is associated with adverse outcomes among people without kidney failure is unknown.

Methods and Results—

We first analyzed the association between AlkP and cardiovascular outcomes among 4115 participants with a previous myocardial infarction (the Cholesterol And Recurrent Events [CARE] study). Results were validated by analyzing the association between AlkP and mortality in an independent sample of 14 716 adults from the general US population (the Third National Health and Nutrition Examination Survey). A graded, independent association was noted between baseline tertile of AlkP and the adjusted hazard ratio of all-cause mortality in CARE participants (
P
trend
=0.02). After adjustment for serum phosphate, hepatic enzymes, and other potential confounders, participants with AlkP in the highest tertile had an adjusted hazard ratio of 1.43 (95% confidence interval 1.08 to 1.89) compared with those in the lowest tertile. Multivariable-adjusted associations between higher AlkP and all-cause and cardiovascular mortality were present in the Third National Health and Nutrition Examination Survey (
P
trend
across tertiles of AlkP=0.006 and 0.038, respectively). Findings from both CARE and the Third National Health and Nutrition Examination Survey were similar among individuals with and without evidence of kidney disease, defined by estimated glomerular filtration rate <60 mL · min
−1
· 1.73 m
−2
.

Conclusions—

We found an independent relation between higher levels of AlkP and adverse outcomes among survivors of myocardial infarction and in a general population sample. The excess risk of death was present in people without evidence of kidney disease and was particularly high among people with higher levels of both AlkP and serum phosphate.
CC Chemokine Receptor-1 Activates Intimal Smooth Muscle–Like Cells in Graft Arterial Disease
Authors: Shimizu Koichi , Minami Manabu , Shubiki Rica , Lopez-Ilasaca Marco , MacFarlane Lindsey , Asami Yukiko , Li Yuxin , Mitchell Richard N. , Libby Peter
Published: October 2009

Background—

Graft arterial disease (GAD) limits long-term solid-organ allograft survival. The thickened intima in GAD contains smooth muscle–like cells (SMLCs), leukocytes, and extracellular matrix. The intimal SMLCs in mouse GAD lesions differ from medial smooth muscle cells in their function and phenotype. Although intimal SMLCs may originate by migration and modulation of donor medial cells or by recruitment of host-derived precursors, the mechanisms that underlie their localization within grafts and the factors that drive these processes remain unclear.

Methods and Results—

This study of aortic transplantation in mice demonstrated an important function for chemokines beyond their traditional role in leukocyte recruitment and activation. Intimal SMLCs, but not medial smooth muscle cells, express functional CC chemokine receptor-1 (CCR1) and respond to RANTES by increased migration and proliferation. Although RANTES infusion in vivo promoted inflammatory cell accumulation in the adventitia of aortic allografts of wild-type and CCR1-deficient recipients, it increased GAD intimal thickening with SMLC proliferation in only the wild-type hosts. Aortic allografts transplanted into CCR1-deficient mice after wild-type bone marrow transplantation did not develop intimal lesions, which indicates that CCR1-bearing inflammatory cells do not contribute to intimal lesion formation. Moreover, RANTES induced SMLC proliferation in vitro but did not promote medial smooth muscle cell growth. Blockade of CCR5 attenuated RANTES-induced T-cell and monocyte/macrophage proliferation but did not affect RANTES-induced SMLC proliferation, consistent with a larger role of CCR1-binding chemokines in SMLC migration and proliferation and GAD development.

Conclusions—

These studies provide a novel mechanistic insight into the formation of vascular intimal hyperplasia and suggest a novel therapeutic strategy for preventing allograft arteriopathy.
N-Terminal Pro-B-Type Natriuretic Peptide Is a Major Predictor of the Development of Atrial Fibrillation
Authors: Patton Kristen K. , Ellinor Patrick T. , Heckbert Susan R. , Christenson Robert H. , DeFilippi Christopher , Gottdiener John S. , Kronmal Richard A.
Published: October 2009

Background—

Atrial fibrillation (AF), the most common cardiac rhythm abnormality, is associated with significant morbidity, mortality, and healthcare expenditures. Elevated B-type natriuretic peptide levels have been associated with the risk of heart failure, AF, and mortality.

Methods and Results—

The relation between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and AF was studied in 5445 Cardiovascular Health Study participants with the use of relative risk regression for predicting prevalent AF and Cox proportional hazards for predicting incident AF. NT-proBNP levels were strongly associated with prevalent AF, with an unadjusted prevalence ratio of 128 for the highest quintile (95% confidence interval, 17.9 to 913.3;
P
<0.001) and adjusted prevalence ratio of 147 for the highest quintile (95% confidence interval, 20.4 to 1064.3;
P
<0.001) compared with the lowest. After a median follow-up of 10 years (maximum of 16 years), there were 1126 cases of incident AF (a rate of 2.2 per 100 person-years). NT-proBNP was highly predictive of incident AF, with an unadjusted hazard ratio of 5.2 (95% confidence interval, 4.3 to 6.4;
P
<0.001) for the development of AF for the highest quintile compared with the lowest; for the same contrast, NT-proBNP remained the strongest predictor of incident AF after adjustment for an extensive number of covariates, including age, sex, medication use, blood pressure, echocardiographic parameters, diabetes mellitus, and heart failure, with an adjusted hazard ratio of 4.0 (95% confidence interval, 3.2 to 5.0;
P
<0.001).

Conclusions—

In a community-based population of older adults, NT-proBNP was a remarkable predictor of incident AF, independent of any other previously described risk factor.