bluuebunny/crossref_metadata_2025 huggingface dataset:
Calibration of models for pile settlement analysis using 64 field load tests
Authors: Zhang L. M. , Xu Y. , Tang W. H.
Published: March 2008

Due to the presence of uncertainties, errors inevitably arise with the estimations of pile settlement. To properly consider serviceability requirements in limit state design, it is necessary to characterize the performance of commonly used settlement prediction models. In this work, information from 64 cases of long driven steel H-piles from field static loading tests in Hong Kong is utilized to evaluate the errors of three settlement prediction models for single piles: two elastic methods and a nonlinear load–transfer method. Commonly adopted soil parameters recommended in two Hong Kong design guidelines are used to reflect the uncertainty arising from evaluation of soil properties. The model error is represented by a bias factor. A conventional statistical analysis was first conducted to study the variability of model bias. A regression analysis method was then proposed as a supplemental analysis of model bias when only limited test data were available or when the measured settlement data distribute in a large range. Both methods result in very similar mean biases. The mean bias of each prediction model tends to vary with the load level and the bearing stratum at the pile toe; while the coefficient of variation of model bias only varies in narrow ranges.
Laboratory characterization of the spatial variability in soils by the EM-wave-based technique
Authors: Wang Yu-Hsing , Dong Xiaobo
Published: March 2008

A slim-form, open-ended coaxial probe with an outside diameter of 2.2 mm was used in this study to take local dielectric measurements in soils. The dielectric relaxation strength of bulk water, Δκw, and the DC conductivity of the saturated sample, σmix, are jointly used to characterize the spatial variability of different specimens including glass beads, sand and mica samples, and kaolinite sediments with two different fabric associations. The pore distribution along the sample depth can be inferred from the local Δκw using mixing rules. The directional feature of the interconnected pores is captured in the tortuosity, which is derived from the measured σmix and the DC conductivity of the pore fluid σpf. In kaolinite sediments, the ratio between the sediment and the pore-fluid conductivity not only reveals the spatial variability of the sediment packing but also the relative contribution of the fluid conductivity and the surface conduction to the overall sediment conductivity.
Field performance, centrifuge testing, and numerical modelling of an induced trench installation
Authors: McAffee Rodney P. , Valsangkar Arun J.
Published: March 2008

The field performance of an induced trench installation is compared to the results of centrifuge testing and numerical modelling. The measured vertical pressure at the crown of the pipe in the field ranged from 0.24 to 0.36 times the overburden pressure. The horizontal earth pressures measured in the field at the springline level determined a coefficient of lateral earth pressure between 0.39 and 0.49. The culvert was monitored over a period of 2 years following completion of embankment construction indicating no measurable changes in earth pressures and deformations. A model box culvert simulating the prototype height of soil cover, the pipe width, and the thickness of the compressible layer was tested using a geotechnical centrifuge. The prototype structure was also evaluated using numerical modelling to predict full earth pressure distribution and deformations. A comparison of field data, centrifuge testing, and numerical modelling shows that the Marston–Spangler theory used in designing induced trench culverts is conservative. The theory however, does not address or predict the nonuniform pressures on the top, sides, or bottom of the pipe, and therefore numerical analysis should be used to estimate the complete pressure distribution.
STRUCTURAL AND MAGNETIC BEHAVIOR OF STRONTIUM-BORATE GLASSES DOPED WITH IRON IONS
Authors: ARDELEAN I. , LUNGU R. , PASCUTA P.
Published: March 2008

Glasses of the x Fe 2 O 3 · (100 - x)[2 B 2 O 3 · SrO ] system (0 ≤ x ≤ 40 mol% ) were prepared and studied by electron paramagnetic resonance (EPR) and magnetic susceptibility measurements. EPR investigations indicated the compositional domains favorable to the presence of isolated iron ions or to those magnetically clustered. The magnetic susceptibility data evidenced the presence of both Fe 3+ and Fe 2+ ions, with their relative content depending on the Fe 2 O 3 concentration. Dipolar and superexchange interactions involving iron ions were revealed depending on the iron content of the sample.
ADIABATIC PROCESS AND CHERN NUMBERS
Authors: GORYO JUN , KOHMOTO MAHITO
Published: March 2008

We study quantum processes with two or more adiabatic parameters. When the parameters are compactified, a derivative of the Hamiltonian is closely related to a first Chern number. This topological formulation is applied to the AC Josephson effect and the spin Hall effect in semiconductors.
IMAGE RECOVERY OF TRANSIENT VOLTAGE BASED ON REAL-TIME MONITORING
Authors: LIU YING , XIE CHI
Published: March 2008

In modern high-energy physics, a powerful electromagnetic field must be supplied for some elementary particles to be accelerated by passing through the region of high-energy physics fields. The electric current and high voltage producing the powerful electromagnetic field are very important to high-energy accelerators, but the insulation of electromagnetic coils in the accelerators suffers from electric damage under powerful electricity. Epecially, it may be stricken by transient overvoltage from the a.c. generator or electric network at any time. For the insulation problem of electromagnetic coils in the accelerator stricken by transient overvoltage, based on real-time monitoring and virtual image technique, the image recovery of transient voltage and the insulation safety of electromagnetic coils in the accelerator can be analyzed and predicted on-line.
COMPARATIVE INSTABILITIES ANALYSIS FOR a-Si:H BODY-TIED TFT (BT-TFT) AND FLOATING BODY TFT (FB-TFT) UNDER BIAS TEMPERATURE STRESSING (BTS)
Authors: LEE YONG K. , CHOA SUNG-HOON
Published: March 2008

The a- Si:H thin film transistors TFT with silicon nitride as a gate insulator have been stressed with negative and positive bias to realize the instability mechanisms. With proposed BT-TFT and FB-TFT devices, it is found that the threshold voltages of both BT-TFT and BT-TFT devices are positively shifted under positive bias stress and then negatively shifted for negative bias stress. The positive threshold voltage shift is due to the electron trapping in the silicon nitride or at the a- Si:H /silicon nitride interface. The negative threshold voltage shift is mainly due to hole trapping and/or electron de-trapping in the silicon nitride or at the a- Si:H /silicon nitride interface. The positive or negative threshold voltage shift keeps increasing with increasing positive or negative gate bias for both BT-TFT and FB-TFT devices. However, as far as the threshold voltage shift slope is concerned, under positive bias stress, both BT-TFT and FB-TFT devices are similar to each other. On the other hand, under negative bias stress, BT-TFT shift amount is much less than one for the FB-TFT device.
SPIN-DEPENDENT TRANSPORT THROUGH A FINITE INTERACTING QUANTUM DOT WITH INTRADOT SPIN-FLIP SCATTERING
Authors: DING KAI-HE , ZHU ZHEN-GANG , LIU XING-HAI
Published: March 2008

Based on the non-equilibrium Green function method, we investigate the spin-dependent transport through a finite interacting quantum dot with intradot spin-flip scattering for non-collinear configuration. It is found that when the intradot spin-flip scattering is applied, the Kondo peaks in the local density of states and the conductance are split, and the splitting peaks are suppressed sharply. By changing the relative orientation of both magnetizations, amplitudes of the splitting peaks appear asymmetric, and reduce with the increasing relative angle θ of the two magnetic moments. It is uncovered that the presence of the spin-flip scattering tends to greatly suppress the spin-valve effect.
AB INITIO CALCULATIONS OF STRUCTURAL AND ELECTRONIC PROPERTIES OF THE COMPOUND Li3AlB2O6
Authors: WU HAIYING , ZHANG HONG , CHENG XINLU , CAI LINGCANG
Published: March 2008

The two equilibrium structures of the compound Li 3 AlB 2 O 6 have been investigated via the minimization of the total energy within Local Spin Density Approximation (LSDA) based on the Density Functional Theory (DFT) in our work. The calculated lattice parameters are all in good agreement with their corresponding experimental values. The relative stability of the two structures are determined. We find that the structure suggested by He et al. is more stable than that proposed by Abdullaev et al. at zero pressure conditions. The reasons for which the structure suggested by He et al. is more stable are also described. Then the electronic properties of the compound Li 3 AlB 2 O 6 including the density of states and energy band structure are successfully obtained and compared for the two structures. We find that the properties of insulator decreases from the structure suggested by He et al. to the structure proposed by Abdullaev et al.
HIERARCHICAL LANGUAGE MODELS FOR EXPERT FINDING IN ENTERPRISE CORPORA
Authors: PETKOVA DESISLAVA , CROFT W. BRUCE
Published: March 2008

Enterprise corpora contain evidence of what employees work on and therefore can be used to automatically find experts on a given topic. We present a general approach for representing the knowledge of a potential expert as a mixture of language models from associated documents. First we retrieve documents given the expert's name using a generative probabilistic technique and weight the retrieved documents according to expert-specific posterior distribution. Then we model the expert indirectly through the set of associated documents, which allows us to exploit their underlying structure and complex language features. Experiments show that our method has excellent performance on the expert search task of the TREC Enterprise track and that it effectively collects and combines evidence for expertise in a heterogeneous collection.
OutRank: A GRAPH-BASED OUTLIER DETECTION FRAMEWORK USING RANDOM WALK
Authors: MOONESINGHE H. D. K. , TAN PANG-NING
Published: March 2008

This paper introduces a stochastic graph-based algorithm, called OutRank, for detecting outliers in data. We consider two approaches for constructing a graph representation of the data, based on the object similarity and number of shared neighbors between objects. The heart of this approach is the Markov chain model that is built upon this graph, which assigns an outlier score to each object. Using this framework, we show that our algorithm is more robust than the existing outlier detection schemes and can effectively address the inherent problems of such schemes. Empirical studies conducted on both real and synthetic data sets show that significant improvements in detection rate and false alarm rate are achieved using the proposed framework.
OPTIMAL BASIC BLOCK INSTRUCTION SCHEDULING FOR MULTIPLE-ISSUE PROCESSORS USING CONSTRAINT PROGRAMMING
Authors: MALIK ABID M. , McINNES JIM , VAN BEEK PETER
Published: March 2008

Instruction scheduling is one of the most important steps for improving the performance of object code produced by a compiler. A fundamental problem that arises in instruction scheduling is to find a minimum length schedule for a basic block — a straight-line sequence of code with a single entry point and a single exit point — subject to precedence, latency, and resource constraints. Solving the problem exactly is NP-complete, and heuristic approaches are currently used in most compilers. In contrast, we present a scheduler that finds provably optimal schedules for basic blocks using techniques from constraint programming. In developing our optimal scheduler, the key to scaling up to large, real problems was in the development of preprocessing techniques for improving the constraint model. We experimentally evaluated our optimal scheduler on the SPEC 2000 integer and floating point benchmarks. On this benchmark suite, the optimal scheduler was very robust — all but a handful of the hundreds of thousands of basic blocks in our benchmark suite were solved optimally within a reasonable time limit — and scaled to the largest basic blocks, including basic blocks with up to 2600 instructions. This compares favorably to the best previous exact approaches.
ON THE RELATIONSHIPS BETWEEN CLUSTERING AND SPATIAL CO-LOCATION PATTERN MINING
Authors: HUANG YAN , ZHANG PUSHENG , ZHANG CHENGYANG
Published: March 2008

The goal of spatial co-location pattern mining is to find subsets of spatial features frequently located together in spatial proximity. Example co-location patterns include services requested frequently and located together from mobile devices (e.g., PDAs and cellular phones) and symbiotic species in ecology (e.g., Nile crocodile and Egyptian plover). Spatial clustering groups similar spatial objects together. Reusing research results in clustering, e.g. algorithms and visualization techniques, by mapping co-location mining problem into a clustering problem would be very useful. However, directly clustering spatial objects from various spatial features may not yield well-defined co-location patterns. Clustering spatial objects in each layer followed by overlaying the layers of clusters may not applicable to many application domains where the spatial objects in some layers are not clustered.

In this paper, we propose a new approach to the problem of mining co-location patterns using clustering techniques. First, we propose a novel framework for co-location mining using clustering techniques. We show that the proximity of two spatial features can be captured by summarizing their spatial objects embedded in a continuous space via various techniques. We define the desired properties of proximity functions compared to similarity functions in clustering. Furthermore, we summarize the properties of a list of popular spatial statistical measures as the proximity functions. Finally, we show that clustering techniques can be applied to reveal the rich structure formed by co-located spatial features. A case study on real datasets shows that our method is effective for mining co-locations from large spatial datasets.
CO-CLUSTERING BIPARTITE WITH PATTERN PRESERVATION FOR TOPIC EXTRACTION
Authors: HU TIANMING , TAN CHEW LIM , TANG YONG , SUNG SAM YUAN , XIONG HUI , QU CHAO
Published: March 2008

The duality between document and word clustering naturally leads to the consideration of storing the document dataset in a bipartite. With documents and words modeled as vertices on two sides respectively, partitioning such a graph yields a co-clustering of words and documents. The topic of each cluster can then be represented by the top words and documents that have highest within-cluster degrees. However, such claims may fail if top words and documents are selected simply because they are very general and frequent. In addition, for those words and documents across several topics, it may not be proper to assign them to a single cluster. In other words, to precisely capture the cluster topic, we need to identify those micro-sets of words/documents that are similar among themselves and as a whole, representative of their respective topics. Along this line, in this paper, we use hyperclique patterns, strongly affiliated words/documents, to define such micro-sets. We introduce a new bipartite formulation that incorporates both word hypercliques and document hypercliques as super vertices. By co-preserving hyperclique patterns during the clustering process, our experiments on real-world data sets show that better clustering results can be obtained in terms of various external clustering validation measures and the cluster topic can be more precisely identified. Also, the partitioned bipartite with co-preserved patterns naturally lends itself to different clustering-related functions in search engines. To that end, we illustrate such an application, returning clustered search results for keyword queries. We show that the topic of each cluster with respect to the current query can be identified more accurately with the words and documents from the patterns than with those top ones from the standard bipartite formulation.
MoSCoE: AN APPROACH FOR COMPOSING WEB SERVICES THROUGH ITERATIVE REFORMULATION OF FUNCTIONAL SPECIFICATIONS
Authors: PATHAK JYOTISHMAN , BASU SAMIK , LUTZ ROBYN , HONAVAR VASANT
Published: March 2008

We propose a specification-driven approach to Web service composition. Our framework allows the users (or service developers) to start with a high-level, possibly incomplete specification of a desired (goal) service that is to be realized using a subset of the available component services. These services are represented using labeled transition systems augmented with guards over variables with infinite domains and are used to determine a strategy for their composition that would realize the goal service functionality. However, in the event the goal service cannot be realized using the available services, our approach identifies the cause(s) for such failure which can then be used by the developer to reformulate the goal specification. Thus, the technique supports Web service composition through iterative reformulation of the functional specification. We present a prototype implementation in a tabled-logic programming environment that illustrates the key features of the proposed approach.
LAZY LEARNER ON DECISION TREE FOR RANKING
Authors: YAN YUHONG , LIANG HAN
Published: March 2008

This paper aims to improve probability-based ranking (e.g. AUC) under decision-tree paradigm. We observe the fact that probability-based ranking is to sort samples in terms of their class probabilities. Therefore, ranking is a relative evaluation metric among those samples. This motivates us to use a lazy learner to explicitly yield a set of unique class probabilities for a testing sample based on its similarities to the training samples within its neighborhood. We embed lazy learners at the leaves of a decision tree to give class probability assignments. This results in the first model, named Lazy Distance-based Tree (LDTree). Then we further improve this model by continuing to grow the tree for the second time, and call the resulting model Eager Distance-based Tree (EDTree). In addition to the benefits of lazy learning, EDTree also takes advantage of the finer resolution of a large tree structure. We compare our models with C4.5, C4.4 and their variants in AUC on a large suite of UCI sample sets. The improvement shows that our method follows a new path that leads to better ranking performance.
POLYNOMIAL REGRESSION WITH AUTOMATED DEGREE: A FUNCTION APPROXIMATOR FOR AUTONOMOUS AGENTS
Authors: STRONGER DANIEL , STONE PETER
Published: March 2008

In order for an autonomous agent to behave robustly in a variety of environments, it must have the ability to learn approximations to many different functions. The function approximator used by such an agent is subject to a number of constraints that may not apply in a traditional supervised learning setting. Many different function approximators exist and are appropriate for different problems. This paper proposes a set of criteria for function approximators for autonomous agents. Additionally, for those problems on which polynomial regression is a candidate technique, the paper presents an enhancement that meets these criteria. In particular, using polynomial regression typically requires a manual choice of the polynomial's degree, trading off between function accuracy and computational and memory efficiency. Polynomial Regression with Automated Degree (PRAD) is a novel function approximation method that uses training data to automatically identify an appropriate degree for the polynomial. PRAD is fully implemented. Empirical tests demonstrate its ability to efficiently and accurately approximate both a wide variety of synthetic functions and real-world data gathered by a mobile robot.
INTELLIGENT NEIGHBORHOOD EXPLORATION IN LOCAL SEARCH METHOD
Authors: DEVARENNE ISABELLE , MABED HAKIM , CAMINADA ALEXANDRE
Published: March 2008

Standard tabu search methods are based on the complete exploration of current solution neighborhood. However, for some problems due to the neighborhood size or to the fitness evaluation complexity, the total exploration of the neighborhood is impractical. The main purpose of this paper is to propose a local search method with no enumeration procedure. In other words, a single solution is examined at each iteration and retained for the future iterations. The idea is to randomly select one solution among a sub-set of the neighborhood of the current one. An adaptive exploration of neighborhood, using extension and restriction mechanisms represented by loop detection and tabu list structure, determines this sub-set. This approach is applied to the K-coloring problem and evaluated on standard benchmarks like DIMACS. The objective is to show how a generic method, without full neighborhood exploration, degradation control and problem-oriented operators, provides a very competitive results comparing to the best dedicated algorithms for graph coloring problems published in the literature.
AN ARTIFICIAL INTELLIGENCE APPROACH TO COURSE TIMETABLING
Authors: LAI LIEN F. , WU CHAO-CHIN , HSUEH NIEN-LIN , HUANG LIANG-TSUNG , HWANG SHIOW-FEN
Published: March 2008

Course Timetabling is a complex problem that cannot be dealt with by using only a few general principles. The various actors (the administrator, the chairman, the instructor and the student) have their own objectives, and these objectives usually conflict. The complexity of the relationships among time slots, classes, classrooms, and instructors makes it difficult to achieve a feasible solution. In this article, we propose an artificial intelligence approach that integrates expert systems and constraint programming to implement a course timetabling system. Expert systems are utilized to incorporate knowledge into the timetabling system and to provide a reasoning capability for knowledge deduction. Separating out the knowledge base, the facts, and the inference engine in expert systems provides greater flexibility in supporting changes. The constraint hierarchy and the constraint network are utilized to capture hard and soft constraints and to reason about constraints by using constraint satisfaction and relaxation techniques. In addition, object-oriented software engineering is applied to improve the development and maintenance of the course timetabling system. A course timetabling system in the Department of Computer Science and Information Engineering at the National Changhua University of Education (NCUE) is used as an illustrative example of the proposed approach.
An Insight Into One of the Top Korean Pharmaceutical Companies — Choongwae Pharma Corporation
Authors: Chun Jae-Kwang
Published: March 2008

The article gives an insight into the background and products of Choongwae Pharma Corporation.
Integrating Diverse Data for Structure Determination of Macromolecular Assemblies
Authors: Alber Frank , Förster Friedrich , Korkin Dmitry , Topf Maya , Sali Andrej
Published: March 2008

To understand the cell, we need to determine the macromolecular assembly structures, which may consist of tens to hundreds of components. First, we review the varied experimental data that characterize the assemblies at several levels of resolution. We then describe computational methods for generating the structures using these data. To maximize completeness, resolution, accuracy, precision, and efficiency of the structure determination, a computational approach is required that uses spatial information from a variety of experimental methods. We propose such an approach, defined by its three main components: a hierarchical representation of the assembly, a scoring function consisting of spatial restraints derived from experimental data, and an optimization method that generates structures consistent with the data. This approach is illustrated by determining the configuration of the 456 proteins in the nuclear pore complex (NPC) from baker's yeast. With these tools, we are poised to integrate structural information gathered at multiple levels of the biological hierarchy—from atoms to cells—into a common framework.
The Origin of Ceratocystis fagacearum, the Oak Wilt Fungus
Authors: Juzwik Jennifer , Harrington Thomas C. , MacDonald William L. , Appel David N.
Published: March 2008

The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown. The pathogen may have been endemic at a low incidence until increased disturbances, changes in land use, and forest management created conditions favorable for disease epidemics. The host genus Quercus contains some relatively resistant species native to the United States, further supporting the hypothesis that the pathogen is native in origin. However, there are also many common, highly susceptible Quercus species—a characteristic typical of introduced pathogens. Most convincingly, studies have shown that the known populations of C. fagacearum have experienced a severe genetic bottleneck that can only be explained by a single introduction. The weight of evidence indicates that C. fagacearum is an introduced pathogen, with possible origins in Central or South America, or Mexico.
Horizontal Stratification in Postsecondary Education: Forms, Explanations, and Implications
Authors: Gerber Theodore P. , Cheung Sin Yi
Published: March 2008

For the past 20 years, social scientists have devoted increasing attention to the links between type of postsecondary education received and socioeconomic inequalities. Borrowing the terminology of Charles & Bradley (2002) , we refer to the forms of these connections as horizontal dimensions of education-based stratification. We review studies of how institutional characteristics (college quality and type) and college experiences (field of specialization, academic performance, and pathway) are related to labor market outcomes. We also discuss research that treats college quality and field of specialization as dependent variables influenced by gender, race, ethnicity, and socioeconomic status. Throughout, we assess alternative theoretical explanations for why and how these horizontal aspects of college education play a stratifying role. We also note methodological developments that raise questions about some of the effects. Mirroring the literature, we emphasize how horizontal dimensions of stratification at the postsecondary level relate to gender differences on both the labor market and education sides. We propose additional theoretical and empirical issues that research on horizontal stratification in postsecondary education should address.
Migraine Intervention With STARFlex Technology (MIST) Trial
Authors: Dowson Andrew , Mullen Michael J. , Peatfield Richard , Muir Keith , Khan Arif Anis , Wells Christopher , Lipscombe Susan L. , Rees Trevor , De Giovanni Joseph V. , Morrison W. Lindsay , Hildick-Smith David , Elrington Giles , Hillis W. Stewart , Malik Iqbal S. , Rickards Anthony
Published: March 2008

Background—

Patent foramen ovale (PFO) is prevalent in patients with migraine with aura. Observational studies show that PFO closure resulted in migraine cessation or improvement in ≈80% of such patients. We investigated the effects of PFO closure for migraine in a randomized, double-blind, sham-controlled trial.

Methods and Results—

Patients who suffered from migraine with aura, experienced frequent migraine attacks, had previously failed ≥2 classes of prophylactic treatments, and had moderate or large right-to-left shunts consistent with the presence of a PFO were randomized to transcatheter PFO closure with the STARFlex implant or to a sham procedure. Patients were followed up for 6 months. The primary efficacy end point was cessation of migraine headache 91 to 180 days after the procedure. In total, 163 of 432 patients (38%) had right-to-left shunts consistent with a moderate or large PFO. One hundred forty-seven patients were randomized. No significant difference was observed in the primary end point of migraine headache cessation between implant and sham groups (3 of 74 versus 3 of 73, respectively;
P
=0.51). Secondary end points also were not achieved. On exploratory analysis, excluding 2 outliers, the implant group demonstrated a greater reduction in total migraine headache days (
P
=0.027). As expected, the implant arm experienced more procedural serious adverse events. All events were transient.

Conclusions—

This trial confirmed the high prevalence of right-to-left shunts in patients with migraine with aura. Although no significant effect was found for primary or secondary end points, the exploratory analysis supports further investigation. The robust design of this study has served as the model for larger trials that are currently underway in the United States and Europe.
Effect of Injectable Alginate Implant on Cardiac Remodeling and Function After Recent and Old Infarcts in Rat
Authors: Landa Natali , Miller Liron , Feinberg Micha S. , Holbova Radka , Shachar Michal , Freeman Inbar , Cohen Smadar , Leor Jonathan
Published: March 2008

Background—

Adverse cardiac remodeling and progression of heart failure after myocardial infarction are associated with excessive and continuous damage to the extracellular matrix. We hypothesized that injection of in situ–forming alginate hydrogel into recent and old infarcts would provide a temporary scaffold and attenuate adverse cardiac remodeling and dysfunction.

Methods and Results—

We developed a novel absorbable biomaterial composed of calcium-crosslinked alginate solution, which displays low viscosity and, after injection into the infarct, undergoes phase transition into hydrogel. To determine the outcome of the biomaterial after injection, calcium-crosslinked biotin-labeled alginate was injected into the infarct 7 days after anterior myocardial infarction in rat. Serial histology studies showed in situ formation of alginate hydrogel implant, which occupied up to 50% of the scar area. The biomaterial was replaced by connective tissue within 6 weeks. Serial echocardiography studies before and 60 days after injection showed that injection of alginate biomaterial into recent (7 days) infarct increased scar thickness and attenuated left ventricular systolic and diastolic dilatation and dysfunction. These beneficial effects were comparable and sometimes superior to those achieved by neonatal cardiomyocyte transplantation. Moreover, injection of alginate biomaterial into old myocardial infarction (60 days) increased scar thickness and improved systolic and diastolic dysfunction.

Conclusions—

We show for the first time that injection of in situ–forming, bioabsorbable alginate hydrogel is an effective acellular strategy that prevents adverse cardiac remodeling and dysfunction in recent and old myocardial infarctions in rat.
Role of Sulfonylurea Receptor Type 1 Subunits of ATP-Sensitive Potassium Channels in Myocardial Ischemia/Reperfusion Injury
Authors: Elrod John W. , Harrell Maddison , Flagg Thomas P. , Gundewar Susheel , Magnuson Mark A. , Nichols Colin G. , Coetzee William A. , Lefer David J.
Published: March 2008

Background—

Opening of cardiac ATP-sensitive potassium channels (K
ATP
channels) is a well-characterized protective mechanism against ischemia and reperfusion injury. Evidence exists for an involvement of both sarcolemmal and mitochondrial K
ATP
channels in such protection. Classically, cardiac sarcolemmal K
ATP
channels are thought to be composed of Kir6.2 (inward-rectifier potassium channel 6.2) and SUR2A (sulfonylurea receptor type 2A) subunits; however, the evidence is strong that SUR1 (sulfonylurea receptor type 1) subunits are also expressed in the heart and that they may have a functional role. The aim of this study, therefore, was to examine the role of SUR1 in myocardial infarction.

Methods and Results—

We subjected mice lacking SUR1 subunits to in vivo myocardial ischemia/reperfusion injury. Interestingly, the SUR1-null mice were markedly protected against the ischemic insult, displaying a reduced infarct size and preservation of left ventricular function, which suggests a role for this K
ATP
channel subunit in cardiovascular function during conditions of stress.

Conclusions—

SUR1 subunits have a high sensitivity toward many sulfonylureas and certain K
ATP
channel–opening drugs. Their potential role during ischemic events should therefore be considered both in the interpretation of experimental data with pharmacological agents and in the clinical arena when the cardiovascular outcome of patients treated with antidiabetic sulfonylureas is being considered.
Heart-Specific Ablation of
Prkar1a
Causes Failure of Heart Development and Myxomagenesis
Authors: Yin Zhirong , Jones Georgette N. , Towns William H. , Zhang Xiaoli , Abel E. Dale , Binkley Philip F. , Jarjoura David , Kirschner Lawrence S.
Published: March 2008

Background—

Protein kinase A signaling has long been known to play an important role in cardiac function. Dysregulation of the protein kinase A system, caused by mutation of the protein kinase A regulatory subunit gene
PRKAR1A
, causes the inherited tumor syndrome Carney complex, which includes cardiac myxomas as one of its cardinal features. Mouse models of this genetic defect have been unsatisfactory because homozygote null animals die early in development and heterozygotes do not exhibit a cardiac phenotype.

Methods and Results—

To study the cardiac-specific effects resulting from complete loss of Prkar1a, we used cre-lox technology to generate mice lacking this protein specifically in cardiomyocytes. Conditional knockout mice died at day 11.5 to 12.5 of embryogenesis with thin-walled, dilated hearts. These hearts showed elevated protein kinase A activity and decreased cardiomyocyte proliferation before demise. Analysis of the expression of transcription factors required for cardiogenesis revealed downregulation of key cardiac transcription factors such as the serum response factor, Gata4, and Nkx2–5. Although heart wall thickness was reduced overall, specific areas exhibited morphological changes consistent with myxomatous degeneration in the walls of knockout hearts.

Conclusions—

Loss of Prkar1a from the heart causes a failure of proper myocardial development with subsequent cardiac failure and embryonic demise. These changes appear to be due to suppression of cardiac-specific transcription by increased protein kinase A activity. These biochemical changes lead to myxoma-like changes, indicating that these mice may be a good model with which to study the formation of these tumors.
Renal Regional Proteomes in Young Dahl Salt-Sensitive Rats
Authors: Tian Zhongmin , Greene Andrew S. , Usa Kristie , Matus Isaac R. , Bauwens Jesse , Pietrusz Jennifer L. , Cowley Allen W. , Liang Mingyu
Published: March 2008

We performed an extensive proteomic analysis of the Dahl model of salt-sensitive hypertension. The consomic SS-13
BN
rat, genetically similar to the Dahl salt-sensitive rat, while exhibiting a significant amelioration of salt-induced hypertension, was used as a control. Proteomic analysis, using differential in-gel electrophoresis and mass spectrometry techniques, was performed in the renal cortex and the renal medulla of 6-week–old SS and SS-13
BN
rats before significant differences in blood pressure were developed between the 2 strains of rat. Several dozen proteins were identified as differentially expressed between SS and SS-13
BN
rats fed the 0.4% NaCl diet or switched to the 4% NaCl diet for 3 days (n=4). The identified proteins were involved in cellular functions or structures including signal transduction, energy metabolism, and the cytoskeleton. The proteomic analysis and subsequent Western blotting indicated that heterogeneous nuclear ribonucleoprotein K in the renal medulla was upregulated by the 4% NaCl diet in SS-13
BN
rats but downregulated in SS rats. The level of angiotensinogen mRNA in the renal medulla was regulated in an opposite manner. Silencing of heterogeneous nuclear ribonucleoprotein K resulted in an upregulation of angiotensinogen in cultured human kidney cells. In summary, we identified significant differences in kidney regional proteomic profiles between SS and SS-13
BN
rats and demonstrated a potential role of heterogeneous nuclear ribonucleoprotein K in the regulation of angiotensinogen expression in the renal medulla.
Maximum Sustainable Yield of Marine Capture Fisheries in Developing Archipelagic States—Balancing Law, Science, Politics and Practice
Authors: Andrew Neil , Lugten Gail
Published: March 2008

The contemporary legal regime for marine capture fisheries is dominated by management based on maximum sustainable yield (MSY). This study examines the law, science, politics and practice of MSY in a selection of developing archipelagic states to assess whether and how MSY is being used in the management of single fish species and as part of a broader ecosystem approach to fisheries management.
Tropospheric Comparisons of Vaisala Radiosondes and Balloon-Borne Frost-Point and Lyman-α Hygrometers during the LAUTLOS-WAVVAP Experiment
Authors: Suortti T. M. , Kivi R. , Kats A. , Yushkov V. , Kämpfer N. , Leiterer U. , Miloshevich L. M. , Neuber R. , Paukkunen A. , Ruppert P. , Vömel H.
Published: March 2008

The accuracy of all types of Vaisala radiosondes and two types of Snow White chilled-mirror hygrosondes was assessed in an intensive in situ comparison with reference hygrometers. Fourteen nighttime reference comparisons were performed to determine a working reference for the radiosonde comparisons. These showed that the night version of the Snow White agreed best with the references [i.e., the NOAA frost-point hygrometer (FPH) and University of Colorado cryogenic frost-point hygrometer (CFH)], but that the daytime version had severe problems with contamination in the humid upper troposphere. Since the RS92 performance was superior to the other radiosondes and to the day version of the Snow White, it was selected to be the working reference. According to the reference comparison, the RS92 has no bias in the mid- and lower troposphere, with deviations <±5% in relative humidity (RH). In the upper troposphere, the RS92 has a ∼5% RH wet bias, which is partly due to the RS92 time lag error and the termination of the heating cycle. It was shown that the time lag effects relating to Vaisala radiosondes can be corrected. Because these were nighttime comparisons, they can be considered to be free from solar radiation effects. Neither the radiosondes nor the Snow White succeeded in reproducing reference class hygrometer profiles in the stratosphere.

According to the 29 radiosonde intercomparisons, the RS92 and the modified RS90 (FN) had the best mutual agreement and no bias. The disagreement is largest (<±10% RH) at low temperatures (T ≪ −30°C), where the FN underestimated (overestimated) in high (low) ambient RH. In comparison with the RS92, the RS90 had a semilinearly increasing wet bias with decreasing temperature, where the bias was ∼10% RH at −60°C. The RS80-A suffers from a large temperature-dependent dry bias in high RH conditions, being over 30% RH at −60°C and ∼5% RH near 0°C. The RS80-A dry bias can be almost totally removed with the correction algorithm by Leiterer et al., which was chosen as the best available. The other approach tested tends to overcorrect in high RH conditions when T < −50°C. For T > −30°C it is ineffective and does not correct the RS80-A dry bias in high ambient RH.
Calibration Assessment of ISCCP Geostationary Infrared Observations Using HIRS
Authors: Knapp Kenneth R.
Published: March 2008

Infrared window (∼11 μm) brightness temperatures from global geostationary meteorological instruments were calibrated using the High Resolution Infrared Radiation Sounder (HIRS) as an independent analysis of the satellite intercalibration performed by the International Satellite Cloud Climatology Project (ISCCP). Criteria for matching geostationary observations with HIRS from previous literature were inadequate to analyze a shift in calibration due to the limited range of resulting temperatures. The result was an inability to determine the impact of a calibration error on observations of cold clouds. To better understand the calibration error, a new set of matchup criteria that collected targets at all temperatures proportionately showed a significant shift in the ISCCP calibration. Using the new criteria, it became apparent that observations of cold temperatures were biased too cold. A correction based on these results removed the bias between the geostationary and HIRS observations.
A Time Series Weather Radar Simulator Based on High-Resolution Atmospheric Models
Authors: Cheong B. L. , Palmer R. D. , Xue M.
Published: March 2008

A three-dimensional radar simulator capable of generating simulated raw time series data for a weather radar has been designed and implemented. The characteristics of the radar signals (amplitude, phase) are derived from the atmospheric fields from a high-resolution numerical weather model, although actual measured fields could be used. A field of thousands of scatterers is populated within the field of view of the virtual radar. Reflectivity characteristics of the targets are determined from well-known parameterization schemes. Doppler characteristics are derived by forcing the discrete scatterers to move with the three-dimensional wind field. Conventional moment-generating radar simulators use atmospheric conditions and a set of weighting functions to produce theoretical moment maps, which allow for the study of radar characteristics and limitations given particular configurations. In contrast to these radar simulators, the algorithm presented here is capable of producing sample-to-sample time series data that are collected by a radar system of virtually any design. Thus, this new radar simulator allows for the test and analysis of advanced topics, such as phased array antennas, clutter mitigation schemes, waveform design studies, and spectral-based methods. Limited examples exemplifying the usefulness and flexibility of the simulator will be provided.
Mesoscale Monitoring of Soil Moisture across a Statewide Network
Authors: Illston Bradley G. , Basara Jeffrey B. , Fiebrich Christopher A. , Crawford Kenneth C. , Hunt Eric , Fisher Daniel K. , Elliott Ronald , Humes Karen
Published: March 2008

Soil moisture is an important component in many hydrologic and land–atmosphere interactions. Understanding the spatial and temporal nature of soil moisture on the mesoscale is vital to determine the influence that land surface processes have on the atmosphere. Recognizing the need for improved in situ soil moisture measurements, the Oklahoma Mesonet, an automated network of 116 remote meteorological stations across Oklahoma, installed Campbell Scientific 229-L devices to measure soil moisture conditions. Herein, background information on the soil moisture measurements, the technical design of the soil moisture network embedded within the Oklahoma Mesonet, and the quality assurance (QA) techniques applied to the observations are provided. This project also demonstrated the importance of operational QA regarding the data collected, whereby the percentage of observations that passed the QA procedures increased significantly once daily QA was applied.
A Modeling Study of Typhoon Nari (2001) at Landfall. Part I: Topographic Effects
Authors: Yang Ming-Jen , Zhang Da-Lin , Huang Hsiao-Ling
Published: March 2008

Although there have been many observational and modeling studies of tropical cyclones, understanding of their intensity and structural changes after landfall is rather limited. In this study, several 84-h cloud-resolving simulations of Typhoon Nari (2001), a typhoon that produced torrential rainfall of more than 1400 mm over Taiwan, are carried out using a quadruply nested–grid mesoscale model whose finest grid size was 2 km. It is shown that the model reproduces reasonably well Nari’s kinematic and precipitation features as well as structural changes, as verified against radar and rain gauge observations. These include the storm track, the contraction and sizes of the eye and eyewall, the spiral rainbands, the rapid pressure rise (∼1.67 hPa h−1) during landfall, and the nearly constant intensity after landfall. In addition, the model captures the horizontal rainfall distribution and some local rainfall maxima associated with Taiwan’s orography.

A series of sensitivity experiments are performed in which Taiwan’s topography is reduced to examine the topographic effects on Nari’s track, intensity, rainfall distribution, and amount. Results show that the impact of island terrain on Nari’s intensity is nearly linear, with stronger storm intensity but less rainfall in lower-terrain runs. In contrast, changing the terrain heights produces nonlinear tracks with circular shapes and variable movements associated with different degrees of blocking effects. Parameter and diagnostic analyses reveal that the nonlinear track dependence on terrain heights results from the complex interactions between the environmental steering flow, Nari’s intensity, and Taiwan’s topography, whereas the terrain-induced damping effects balance the intensifying effects of latent heat release associated with the torrential rainfall in maintaining the near-constant storm intensity after landfall.
Methods for Starting the Detection of Undocumented Multiple Changepoints
Authors: Gérard-Marchant Pierre G. F. , Stooksbury David E. , Seymour Lynne
Published: March 2008

Four algorithms are given, as a first step toward the practical detection of undocumented multiple changepoints. These algorithms are based on the two-phase regression method of Lund and Reeves, as well as the robust method of Lazante. The result of each method is a set that contains statistically detectable changepoints; each candidate is then either independently validated as a changepoint or discarded. This is demonstrated and the methods are compared on artificial data, and then the methods are implemented on streamflow data from the Flint River in southwest Georgia. Most notably, the method based on two-phase regression was able to detect a well-known yet undocumented drop in streamflow from a local drought that no other methods have so far been able to detect.
Unstable Frontal Waves along the Kuroshio Extension with Low-Potential Vorticity Intermediate Oyashio Water
Authors: Kouketsu Shinya , Yasuda Ichiro
Published: March 2008

A linear stability analysis was conducted for a three-layer primitive equation model including viscosity with a basic state, which modeled the stratification and velocity fields with the vertical and horizontal variations across the Kuroshio Extension. An unstable wave with a wavelength of 220 km and a phase speed of 0.24 m s−1 propagating in the downstream direction was found to grow the fastest. Characteristics of this unstable baroclinic wave were similar to those of waves observed along the Kuroshio Extension. The growth rate of the fastest-growing waves became greater with an increase of the cross-stream difference of the potential vorticity (PV) in the intermediate layer. For a cross-frontal stratification structure without the PV gradient in the intermediate layer, which is similar to that in the Gulf Stream, the wavelength of the fastest-growing unstable wave changed to 390 km and the unstable wave had a much different structure. Thus, the unstable frontal waves observed along the Kuroshio Extension occur only for the cases when low-PV Oyashio water exists on the northern side of the main stream in the intermediate layer. The unstable frontal waves revealed in the present study greatly contribute to the formation of a clear salinity minimum in the Kuroshio Extension.