bluuebunny/crossref_metadata_2025 huggingface dataset:
Mammalian 105 kDa heat shock family proteins suppress hydrogen peroxide‐induced apoptosis through a p38 MAPK‐dependent mitochondrial pathway in HeLa cells
Authors: Yamagishi Nobuyuki , Saito Youhei , Hatayama Takumi
Published: August 2008

Hsp105α and Hsp105β are major heat shock proteins in mammalian cells that belong to a subgroup of the HSP70 family, HSP105/110. Previously, we have shown that Hsp105α has opposite effects on stress‐induced apoptosis depending on the cell type. However, it is not fully understood how Hsp105 regulates stress‐induced apoptosis. In this study, we examined how Hsp105α and Hsp105β regulate H2O2‐induced apoptosis by using HeLa cells in which expression of Hsp105α or Hsp105β was regulated using doxycycline. Overexpression of Hsp105α and Hsp105β suppressed the activation of caspase‐3 and caspase‐9 by preventing the release of cytochrome c from mitochondria in H2O2‐treated cells. Furthermore, both c‐Jun N‐terminal kinase (JNK) and p38 mitogen‐activated protein kinase (p38 MAPK) were activated by treatment with H2O2, and the activation of both kinases was suppressed by overexpression of Hsp105α and Hsp105β. However, H2O2‐induced apoptosis was suppressed by treatment with a potent inhibitor of p38 MAPK, SB202190, but not a JNK inhibitor, SP600125. These findings suggest that Hsp105α and Hsp105β suppress H2O2‐induced apoptosis by suppression of p38 MAPK signaling, one of the essential pathways for apoptosis.
IMPACT OF CRYSTALLINE MILK FAT ON RHEOLOGICAL PROPERTIES OF ICE CREAM MIX EMULSIONS DURING AGING TIME AT 4C
Authors: BAZMI ALI , LAUNAY BERNARD , CUVELIER GÉRARD , RELKIN PERLA
Published: August 2008

The influence of aging time at 4C has been studied for three ice cream mix emulsions containing 10% weight fraction of milk fat samples differing by their composition. Milk fat composition was varied by partially replacing anhydrous milk fat (AMF) either by a high melting temperature, stearin (AMF/S), or a low melting temperature, oleain (AMF/O) fraction. Among the three ice cream mix emulsions, the AMF/O emulsion containing the lowest proportion of saturated triglycerides had slightly lower proportion of high‐size fat droplets regardless of the storage time periods, but it presented a higher shear sensitive behavior with aging time. In addition, the structural recovery following a shearing test (100/s for 1 min) observed in fresh emulsions was in the following order: AMF/S > AMF > AMF/O. However, structural recovery decreased faster with aging time for AMF/S than AMF, while it remained unchanged for AMF/O emulsion, where development of crystalline fat was most delayed. Based on these results, it is suggested that different shear stability and structure recovery after shearing can be related to the rate of development of fat crystals in the milk fat droplets which affects the interaction properties between the weak network of biopolymers in the aqueous phase and the fat droplets in the emulsions, depending on milk fat composition.

PRACTICAL APPLICATION

Our studies indicated an important role of unsaturated milk fat on the functional properties of ice cream mix emulsions, through modifying their rheological behavior as a result of changes in the crystallization properties of the fat in the emulsion droplets. We showed that higher amount of crystallized fat may prevent structure enhancement in the emulsions, and the resultant structure is more sensitive against shearing. This phenomenon will have effects on the aging time of the emulsions at 4C before whipping and, finally, on their overrun and the microstructure of incorporated air bubbles, which have been discussed elsewhere (Bazmi et al. 2007).
STANDARD SCALES FOR CRISPNESS, CRACKLINESS AND CRUNCHINESS IN DRY AND WET FOODS: RELATIONSHIP WITH ACOUSTICAL DETERMINATIONS
Authors: CHAUVIN MAITE A. , YOUNCE FRANK , ROSS CAROLYN , SWANSON BARRY
Published: August 2008

A trained panel developed rating scales for crispness, crunchiness and crackliness for dry and wet foods based on the auditory perception of selected foods. The newly developed scales were then evaluated by 40 untrained panelists and the sound perception of standard foods was assessed through the analysis of the root mean square (RMS) of the 5‐s audio waveforms and multidimensional scaling (MDS). The RMS was highly correlated to auditory sensory perception of crispness (r = 0.83 and 0.96), crunchiness (r = 0.99 and 0.99) and crackliness (r = 0.88 and 0.96) for dry and wet foods, respectively. MDS technique applied for the 40 untrained panelists was instructive in assessing auditory textural differences of naïve panelists and a useful statistical instrument to graphically validate selected scales. Auditory perception of the selected foods were rated similarly using standard auditory texture scales for crispness, crunchiness and crackliness developed by the trained panel (oral evaluation) and MDS results from the untrained panel (recordings).

PRACTICAL APPLICATIONS

Crispness, crunchiness and crackliness are not only important and useful descriptors of food texture, but are also desirable textural qualities in many foods. The lack of consistency in the procedures used for the evaluation of crunchy, crispy and crackly in sensory studies often results in confusion when training expert panels. Research will benefit textural studies through an improvement of consistent textural definitions and development of standard scales and evaluation techniques.

The crispness, crunchiness and crackliness scales developed and applied in the current study represent a new potential standard frame of reference that may be used for training panelists in texture parameters related to food auditory perception. The scales may be considered illustrations demonstrating full and practical ranges for each texture attribute with regard to analyzing auditory parameters of foods and effective objective tools for assessing panelists in descriptive analysis.
Mobile Methodologies: Theory, Technology and Practice
Authors: Hein Jane Ricketts , Evans James , Jones Phil
Published: August 2008

This article reviews developments in ‘mobile methodologies’, looking at the theory, technologies and practice of mobile methods. We focus specifically on methods where the research subject and researcher are in motion in the ‘field’, and seek to understand what difference mobile methods can make to research. Drawing on the broader mobilities paradigm, we identify the key tenets of mobile methodologies, and then discuss the role that technologies such as geographical information systems can play in opening up this new approach to research. The article reviews past and present work that has utilised mobile methods, highlighting key opportunities and challenges. We consider current attempts to use geographical information systems to rigorously investigate the effect that walking has on an interview process, and conclude by summarising the potential for mobile methods to inform social scientific research.
Citizenship, Migration and Transnationalism: A Review and Critical Interventions
Authors: Ho Elaine Lynn‐Ee
Published: August 2008

This article reviews the extant literature on citizenship and transnationalism, paying particular attention to the impact of migration on citizenship models and practices. I further address three areas of inquiry that have lagged behind in this scholarship. First, I highlight the neglect of emotions in the study of citizenship and transnational migration. Second, I criticise the tendency for scholars to privilege the experiences of immigration regimes at the expense of sending state experiences. Finally, I use selected examples to underscore the importance of studying citizenship trajectories outside of the Anglo‐American and European contexts. These critical interventions signal new approaches to advance the scholarship on citizenship, migration and transnationalism.
Metabolically engineered Escherichia coli for efficient production of glycosylated natural products
Authors: Peirú Salvador , Rodríguez Eduardo , Menzella Hugo G. , Carney John R. , Gramajo Hugo
Published: August 2008

Significant achievements in polyketide gene expression have made Escherichia coli one of the most promising hosts for the heterologous production of pharmacologically important polyketides. However, attempts to produce glycosylated polyketides, by the expression of heterologous sugar pathways, have been hampered until now by the low levels of glycosylated compounds produced by the recombinant hosts. By carrying out metabolic engineering of three endogenous pathways that lead to the synthesis of TDP sugars in E. coli, we have greatly improved the intracellular levels of the common deoxysugar intermediate TDP‐4‐keto‐6‐deoxyglucose resulting in increased production of the heterologous sugars TDP‐L‐mycarose and TDP‐d‐desosamine, both components of medically important polyketides. Bioconversion experiments carried out by feeding 6‐deoxyerythronolide B (6‐dEB) or 3‐α‐mycarosylerythronolide B (MEB) demonstrated that the genetically modified E. coli B strain was able to produce 60‐ and 25‐fold more erythromycin D (EryD) than the original strain K207‐3, respectively. Moreover, the additional knockout of the multidrug efflux pump AcrAB further improved the ability of the engineered strain to produce these glycosylated compounds. These results open the possibility of using E. coli as a generic host for the industrial scale production of glycosylated polyketides, and to combine the polyketide and deoxysugar combinatorial approaches with suitable glycosyltransferases to yield massive libraries of novel compounds with variations in both the aglycone and the tailoring sugars.
Manganese‐oxidizing bacteria mediate the degradation of 17α‐ethinylestradiol
Authors: Sabirova Julia S. , Cloetens L. F. F. , Vanhaecke L. , Forrez I. , Verstraete Willy , Boon N.
Published: August 2008

Manganese (II) and manganese‐oxidizing bacteria were used as an efficient biological system for the degradation of the xenoestrogen 17α‐ethinylestradiol (EE2) at trace concentrations. Mn2+‐derived higher oxidation states of Mn (Mn3+, Mn4+) by Mn2+‐oxidizing bacteria mediate the oxidative cleavage of the polycyclic target compound EE2. The presence of manganese (II) was found to be essential for the degradation of EE2 by Leptothrix discophora, Pseudomonas putida MB1, P. putida MB6 and P. putida MB29. Mn2+‐dependent degradation of EE2 was found to be a slow process, which requires multi‐fold excess of Mn2+ and occurs in the late stationary phase of growth, implying a chemical process taking place. EE2‐derived degradation products were shown to no longer exhibit undesirable estrogenic activity.
DYNAMIC ANALYSIS OF FRAMES WITH MATERIAL AND GEOMETRIC NONLINEARITIES BASED ON THE SEMIRIGID TECHNIQUE
Authors: AU F. T. K. , YAN Z. H.
Published: August 2008

This paper presents a method for nonlinear dynamic analysis of frames with material and geometric nonlinearities which is based on the semirigid technique. The plastic hinge that accounts for the material nonlinearity is modeled as a pseudo-semirigid connection with nonlinear hysteretic moment-curvature characteristics at the element ends. The stiffness matrix of a frame element with material and geometric nonlinearities is expressed as the sum of products of the standard stiffness matrix and the geometric stiffness matrix of the element, with their corresponding correction matrices based on the plasticity factors developed from the section flexural stiffness at the plastic hinge locations. The combined stress yield condition is used for the force state determination of plastic hinges, and force equilibrium iterations and geometry updating for frames are carried out in every time step. When the key parameters of a structure are updated in a time step, the time step is split up into substeps to ensure accuracy while keeping the computations to a reasonable amount. The plastic rotation history can be calculated directly or in an approximate indirect way. The method is computationally efficient and it needs no additional connection elements, which makes it convenient for incorporation into existing linear dynamic analysis programs. Besides, the method can handle accurately and efficiently the dynamic analysis of nonlinear frames using relatively large time steps in conjunction with time step subdivision to cope with key parameter changes. A portal frame is used to verify the correctness of the proposed method. A more complicated five-story frame is used to illustrate the applicability and performance of the proposed method.
EFFICIENT METHODS FOR STRUCTURAL OPTIMIZATION WITH FREQUENCY CONSTRAINTS USING HIGHER ORDER APPROXIMATIONS
Authors: TORKZADEH P. , SALAJEGHEH J. , SALAJEGHEH E.
Published: August 2008

Presented herein are four different methods for the optimum design of structures subject to multiple natural frequency constraints. During the optimization process the optimum cross-sectional dimensions of elements are determined. These methods are robust and efficient in terms of the number of eigenvalue analyses required, as well as the overall computational time for the optimum design. A new third order approximate function is presented for the structural response quantities, as functions of the cross-sectional properties, and four different methods for the optimum design are defined based on this approximate function. The main features of the proposed function are that only the diagonal terms of higher order derivative matrices are employed, and these derivatives are established by the available first order derivatives. The first order exact derivatives are obtained from a sensitivity analysis at the previous design points. We show that this approximate function creates high quality approximations of the structural responses, such as the frequencies. Examples are presented and the efficiency and quality of the proposed methods are discussed and compared.
AN ITERATIVE APPROACH TO LINEAR TORSION ANALYSIS OF WEB-TAPERED I-BEAMS USING A UNIFORM I-BEAM ELEMENT
Authors: YAU JONG-DAR
Published: August 2008

Uniform I-beam elements are not suitable for simulating the torsional behavior of web-tapered I-beams since they fail to account for the torsional effect associated with web-tapering. To resolve this problem, an iterative approach is presented for computing the linear torsional response of web-tapered I-beams using an existing uniform I-beam element. An iterative procedure includes three phases: predictor, corrector, and error-checking. In this paper, the predictor is a solution of the structural displacements using the conventional uniform I-beam elements, and the corrector is concerned with recovery of internal forces, in which the element forces are computed in an analytical way, taking into account the torsional effect of a twisted I-beam considering web-tapering. The applicability and accuracy of the iterative approach presented herein are confirmed by comparing the computed responses for a torsionally loaded I-beam with varied web-tapering to the exact solutions.
Detached-Eddy Simulation
Authors: Spalart Philippe R.
Published: August 2008

Detached-eddy simulation (DES) was first proposed in 1997 and first used in 1999, so its full history can be surveyed. A DES community has formed, with adepts and critics, as well as new branches. The initial motivation of high–Reynolds number, massively separated flows remains, for which DES is convincingly more capable presently than either unsteady Reynolds-averaged Navier-Stokes (RANS) or large-eddy simulation (LES). This review discusses compelling examples, noting the visual and quantitative success of DES. Its principal weakness is its response to ambiguous grids, in which the wall-parallel grid spacing is of the order of the boundary-layer thickness. In some situations, DES on a given grid is then less accurate than RANS on the same grid or DES on a coarser grid. Partial remedies have been found, yet dealing with thickening boundary layers and shallow separation bubbles is a central challenge. The nonmonotonic response of DES to grid refinement is disturbing to most observers, as is the absence of a theoretical order of accuracy. These issues also affect LES in any nontrivial flow. This review also covers the numerical needs of DES, gridding practices, coupling with different RANS models, derivative uses such as wall modeling in LES, and extensions such as zonal DES and delayed DES.
How Shelterin Protects Mammalian Telomeres
Authors: Palm Wilhelm , de Lange Titia
Published: August 2008

The genomes of prokaryotes and eukaryotic organelles are usually circular as are most plasmids and viral genomes. In contrast, the nuclear genomes of eukaryotes are organized on linear chromosomes, which require mechanisms to protect and replicate DNA ends. Eukaryotes navigate these problemswith the advent of telomeres, protective nucleoprotein complexes at the ends of linear chromosomes, and telomerase, the enzyme that maintains the DNA in these structures. Mammalian telomeres contain a specific protein complex, shelterin, that functions to protect chromosome ends from all aspects of the DNA damage response and regulates telomere maintenance by telomerase. Recent experiments, discussed here, have revealed how shelterin represses the ATM and ATR kinase signaling pathways and hides chromosome ends from nonhomologous end joining and homology-directed repair.
The Take and Give Between Retrotransposable Elements and their Hosts
Authors: Beauregard Arthur , Curcio M. Joan , Belfort Marlene
Published: August 2008

Retrotransposons mobilize via RNA intermediates and usually carry with them the agent of their mobility, reverse transcriptase. Retrotransposons are streamlined, and therefore rely on host factors to proliferate. However, retrotransposons are exposed to cellular forces that block their paths. For this review, we have selected for our focus elements from among target-primed (TP) retrotransposons, also called non-LTR retrotransposons, and extrachromosomally-primed (EP) retrotransposons, also called LTR retrotransposons. The TP retrotransposons considered here are group II introns, LINEs and SINEs, whereas the EP elments considered are the Ty and Tf retrotransposons, with a brief comparison to retroviruses. Recurring themes for these elements, in hosts ranging from bacteria to humans, are tie-ins of the retrotransposons to RNA metabolism, DNA replication and repair, and cellular stress. Likewise, there are parallels among host-cell defenses to combat rampant retrotransposon spread. The interactions between the retrotransposon and the host, and their coevolution to balance the tension between retrotransposon proliferation and host survival, form the basis of this review.
Transposon Tn5
Authors: Reznikoff William S.
Published: August 2008

Tn5 was one of the first transposons to be identified ( 10 ). As a result of Tn5's early discovery and its simple macromolecular requirements for transposition, the Tn5 system has been a very productive tool for studying the molecular mechanism of DNA transposition. These studies are of broad value because they offer insights into DNA transposition in general, because DNA transposition is a useful model with which to understand other types of protein-DNA interactions such as retroviral DNA integration and the DNA cleavage events involved in immunoglobulin gene formation, and because Tn5-derived tools are useful adjuncts in genetic experimentation.
The Origins of Plant Pathogens in Agro-Ecosystems
Authors: Stukenbrock Eva H. , McDonald Bruce A.
Published: August 2008

Plant pathogens can emerge in agricultural ecosystems through several mechanisms, including host-tracking, host jumps, hybridization and horizontal gene transfer. High-throughput DNA sequencing coupled with new analytical approaches make it possible to differentiate among these mechanisms and to infer the time and place where pathogens first emerged. We present several examples to illustrate the different mechanisms and timescales associated with the origins of important plant pathogens. In some cases pathogens were domesticated along with their hosts during the invention of agriculture approximately 10,000 years ago. In other cases pathogens appear to have emerged very recently and almost instantaneously following horizontal gene transfer or hybridization. The predominant unifying feature in these examples is the environmental and genetic uniformity of the agricultural ecosystem in which the pathogens emerged. We conclude that agro-ecosystems will continue to select for new pathogens unless they are re-engineered to make them less conducive to pathogen emergence.
Models of Fungicide Resistance Dynamics
Authors: van den Bosch Frank , Gilligan Christopher A.
Published: August 2008

We describe two classes of models used for fungicide and antibiotic resistance dynamics. One class assumes that the density of the pathogen (or severity of the disease caused by the pathogen) has no feedback effects on the rate at which new infections arise. The second class does not make this assumption. A quantitative relationship between these two classes is derived. We then discuss the two sets of assumptions made in the literature about initial conditions: either both the fungicide-sensitive strain and the -resistant strain are initially at low density, or the sensitive strain is resident at nonlow density and the resistant strain is initially at low density. We show that models of fungicide resistance dynamics with and without density-dependent feedback give contrasting predictions on the effects of pathogen life-cycle parameters and the effects of the fungicide (dose, frequency, use of mixtures, spatial usage restrictions) on the evolution, invasion, and spread of fungicide resistance. We further show that the evaluation of a resistance management strategy requires a very precise definition of what constitutes a good strategy.
Plants as a Habitat for Beneficial and/or Human Pathogenic Bacteria
Authors: Tyler Heather L. , Triplett Eric W.
Published: August 2008

Non-plant pathogenic endophytic bacteria can promote plant growth, improve nitrogen nutrition, and, in some cases, are human pathogens. Recent work in several laboratories has shown that enteric bacteria are common inhabitants of the interior of plants. These observations led to the experiments that showed the entry into plants of enteric human pathogens such as Salmonella and E. coli O157:H7. The extent of endophytic colonization by strains is regulated by plant defenses and several genetic determinants necessary for this interior colonization in endophytic bacteria have been identified. The genomes of four endophytic bacteria now available should promote discovery of other genes that contribute to this phenotype. Common virulence factors in plant and animal pathogens have also been described in bacteria that can infect both plant and animal models. Future directions in all of these areas are proposed.
Epidemiological Models for Invasion and Persistence of Pathogens
Authors: Gilligan Christopher A. , van den Bosch Frank
Published: August 2008

Motivated by questions such as “Why do some diseases take off, while others die out?” and “How can we optimize the deployment of control methods,” we introduce simple epidemiological concepts for the invasion and persistence of plant pathogens. An overarching modeling framework is then presented that can be used to analyze disease invasion and persistence at a range of scales from the microscopic to the regional. Criteria for invasion and persistence are introduced, initially for simple models of epidemics, and then for models with greater biological realism. Some ways in which epidemiological models are used to identify optimal strategies for the control of disease are discussed. Particular attention is given to the spatial structure of host populations and to the role of chance events in determining invasion and persistence of plant pathogens. Finally, three brief case studies are used to illustrate the practical applications of epidemiological theory to understand invasion and persistence of plant pathogens. These comprise long-term predictions for the persistence and control of Dutch elm disease; identification of methods to manage the spread of rhizomania on sugar beet in the U.K. by matching the scale of control with the spatial and temporal scales of the disease; and analysis of evolutionary change in virus control to identify risks of inadvertent selection for damaging virus strains.
A Spiking Neural Network Model of an Actor-Critic Learning Agent
Authors: Potjans Wiebke , Morrison Abigail , Diesmann Markus
Published: August 2008

The ability to adapt behavior to maximize reward as a result of interactions with the environment is crucial for the survival of any higher organism. In the framework of reinforcement learning, temporal-difference learning algorithms provide an effective strategy for such goal-directed adaptation, but it is unclear to what extent these algorithms are compatible with neural computation. In this article, we present a spiking neural network model that implements actor-critic temporal-difference learning by combining local plasticity rules with a global reward signal. The network is capable of solving a nontrivial gridworld task with sparse rewards. We derive a quantitative mapping of plasticity parameters and synaptic weights to the corresponding variables in the standard algorithmic formulation and demonstrate that the network learns with a similar speed to its discrete time counterpart and attains the same equilibrium performance.
A Numerical Case Study on the Initiation of the Madden–Julian Oscillation
Authors: Ray Pallav , Zhang Chidong , Dudhia Jim , Chen Shuyi S.
Published: August 2008

A mesoscale tropical channel model is used to study the long-standing problem of the initiation of the Madden–Julian oscillation (MJO). With initial and lateral boundary conditions provided by a global reanalysis, this model is able to reproduce the initiation and gross features of two observed MJO events up to 2 months after the start of simulations. This leads to a conjecture that these two MJO events are generated by the influences from the lateral boundaries. This conjecture is supported by a series of sensitivity tests. These sensitivity tests demonstrate that the simulated MJO initiation does not critically depend on detailed characteristics of sea surface temperature (varying versus constant in time, mean distribution from boreal spring versus winter), initial conditions (within a 10-day period), the latitudinal location of the lateral boundaries (21°–38°N and S), or even latent heating and moist processes. The only factor found critical to the reproduction of the MJO initiation is time-varying lateral boundary conditions from the reanalysis. When such lateral boundary conditions are replaced by time-independent conditions, the model fails to reproduce the MJO initiation. These results support the idea that extratropical influences can be an efficient mechanism for MJO initiation. Implications of these results are discussed.
Impact of the Madden–Julian Oscillation on Summer Rainfall in Southeast China
Authors: Zhang Lina , Wang Bizheng , Zeng Qingcun
Published: August 2008

The impact of the Madden–Julian oscillation (MJO) on summer rainfall in Southeast China is investigated using the Real-time Multivariate MJO (RMM) index and the observational rainfall data. A marked transition of rainfall patterns from being enhanced to being suppressed is found in Southeast China (east of 105°E and south of 35°N) on intraseasonal time scales as the MJO convective center moves from the Indian Ocean to the western Pacific Ocean. The maximum positive and negative anomalies of regional mean rainfall are in excess of 10% relative to the climatological regional mean. Such different rainfall regimes are associated with the corresponding changes in physical fields such as the western Pacific subtropical high (WPSH), moisture, and vertical motions. When the MJO is mainly over the Indian Ocean, the WPSH shifts farther westward, and the moisture and upward motions in Southeast China are increased. In contrast, when the MJO enters the western Pacific, the WPSH retreats eastward, and the moisture and upward motions in Southeast China are decreased.

It is suggested that the MJO may influence summer rainfall in Southeast China through remote and local dynamical mechanisms, which correspond to the rainfall enhancement and suppression, respectively. The remote role is the energy propagation of the Rossby wave forced by the MJO-related heating over the Indian Ocean through the low-level westerly waveguide from the tropical Indian Ocean to Southeast China. The local role is the northward shift of the upward branch of the anomalous meridional circulation when the MJO is over the western Pacific, which causes eastward retreat of the WPSH and suppressed moisture transport toward Southeast China.
The Tree-Ring Record of Drought on the Canadian Prairiesa,b
Authors: St. George Scott , Meko David M. , Girardin Martin-Philippe , MacDonald Glen M. , Nielsen Erik , Pederson Greg T. , Sauchyn David J. , Tardif Jacques C. , Watson Emma
Published: August 2008

Ring-width data from 138 sites in the Canadian Prairie Provinces and adjacent regions are used to estimate summer drought severity during the past several hundred years. The network was divided into five regional groups based on geography, tree species, and length of record: the eastern Rockies, northern Saskatchewan, central Manitoba, southern Manitoba, and northwestern Ontario. Regional tree-ring records are primarily related to summer moisture and drought conditions, and are less responsive to droughts caused by deficits in winter precipitation. These summer-sensitive data are not linearly related to major modes of climate variability, including ENSO and the Pacific decadal oscillation (PDO), which primarily affect the climate of western Canada during winter. Extended drought records inferred from tree rings indicate that drought on the Canadian Prairies has exhibited considerable spatial heterogeneity over the last several centuries. For northern Saskatchewan and northwestern Ontario, intervals of persistently low tree growth during the twentieth century were just as long as or longer than low-growth intervals in the eighteenth or nineteenth centuries. Longer records from southern Alberta suggest that the most intense dry spell in that area during the last 500 yr occurred during the 1720s. At the eastern side of the prairies, the longest dry event is centered around 1700 and may coincide with low lake stands in Manitoba, Minnesota, and North Dakota. Although the Canadian Prairies were dry at times during the 1500s, there is no regional analog to the sixteenth-century “megadroughts” that affected much of the western United States and northern Mexico.
Precipitation, Recycling, and Land Memory: An Integrated Analysis
Authors: Dirmeyer Paul A. , Schlosser C. Adam , Brubaker Kaye L.
Published: August 2008

A synthesis of several approaches to quantifying land–atmosphere interactions is presented. These approaches use data from observations or atmospheric reanalyses applied to atmospheric tracer models and stand-alone land surface schemes. None of these approaches relies on the results of general circulation model simulations. A high degree of correlation is found among these independent approaches, and constructed here is a composite assessment of global land–atmosphere feedback strength as a function of season. The composite combines the characteristics of persistence of soil moisture anomalies, strong soil moisture regulation of evaporation rates, and reinforcement of water cycle anomalies through recycling. The regions and seasons that have a strong composite signal predominate in both summer and winter monsoon regions in the period after the rainy season wanes. However, there are exceptions to this pattern, most notably over the Great Plains of North America and the Pampas/Pantanal of South America, where there are signs of land–atmosphere feedback throughout most of the year. Soil moisture memory in many of these regions is long enough to suggest that real-time monitoring and accurate initialization of the land surface in forecast models could lead to improvements in medium-range weather to subseasonal climate forecasts.
Overturning Circulation in an Eddy-Resolving Model: The Effect of the Pole-to-Pole Temperature Gradient
Authors: Wolfe Christopher L. , Cessi Paola
Published: August 2008

The effect of the pole-to-pole surface temperature difference on the deep stratification and the strength of the global meridional overturning circulation (MOC) is examined in an eddy-resolving ocean model configured in an idealized domain roughly representing the Atlantic sector. Mesoscale eddies lead to qualitative differences in the mean stratification and the MOC compared to laminar (i.e., eddy free) models. For example, the spreading of fluid across the model’s representation of the Antarctic Circumpolar Current (ACC) no longer relies on the existence of a sill in the ACC. In addition, the deep- and bottom-water masses—roughly representing North Atlantic Deep Water (NADW) and Antarctic Bottom Water (ABW), respectively—are eroded by the eddies so that their zonal and meridional extents are much smaller than in the laminar case. It is found that if the north pole temperature is sufficiently warm, the formation of northern deep water is suppressed and the middepth cell is small and weak while the deep cell is large and vigorous. In contrast, if the north pole temperature is in the range of the southern channel temperatures, the middepth cell is large and strong while the deep cell has a reduced amplitude. This result is consistent with the predictions of the laminar theory of the MOC. In contrast to the laminar theory, realistically strong deep stratification is formed even if the temperature at the northern sinking site is warmer than any temperature found in the channel. Indeed, middepth stratification is actually stronger in the latter case than the former case.
Presenting the Snowflake Video Imager (SVI)
Authors: Newman Andrew J. , Kucera Paul A. , Bliven Larry F.
Published: August 2008

Herein the authors introduce the Snowflake Video Imager (SVI), which is a new instrument for characterizing frozen precipitation. An SVI utilizes a video camera with sufficient frame rate, pixels, and shutter speed to record thousands of snowflake images. The camera housing and lighting produce little airflow distortion, so SVI data are quite representative of natural conditions, which is important for volumetric data products such as snowflake size distributions. Long-duration, unattended operation of an SVI is feasible because datalogging software provides data compression and the hardware can operate for months in harsh winter conditions. Details of SVI hardware and field operation are given. Snowflake size distributions (SSDs) from a storm near Boulder, Colorado, are computed. An SVI is an imaging system, so SVI data can be utilized to compute diverse data products for various applications. In this paper, the authors present visualizations of frozen particles (i.e., snowflake aggregates as well as individual crystals), which provide insight into the weather conditions such as temperature, humidity, and winds.
An Algorithm for Tracking Eyes of Tropical Cyclones
Authors: Chang Pao-Liang , Jong-Dao Jou Ben , Zhang Jian
Published: August 2008

A tropical cyclone (TC) eye tracking (TCET) algorithm is presented in this study to objectively identify and track the eye and center of a tropical cyclone using radar reflectivity data. Twelve typhoon cases were studied for evaluating the TCET algorithm. Results show that the TCET can track TC centers for several hours. The longest tracking time is about 35 h. Eye locations estimated from different radars showed consistency with a mean distance bias of about 3.5 km and a standard deviation of about 1.5 km. The TCET analysis shows decreasing eye radius as TCs approach land, especially within 50 km of the coastline.

The TCET algorithm is computationally efficient and can be automated by using the TC center in the previous volume or the estimated center from satellite images as an initial guess. The TCET may not accurately find the TC center when a TC is weak or does not have an enclosed eyewall or when it does have highly noncircular eyes. However, the algorithm is still suitable for operational implementation and provides high spatial and temporal resolution information for TC centers and eye radii, especially for intense TCs.
Environmental Ingredients for Supercells and Tornadoes within Hurricane Ivan
Authors: Baker Adam K. , Parker Matthew D. , Eastin Matthew D.
Published: August 2008

Hurricane Ivan (2004) was a prolific producer of tornadoes as it made landfall on the U.S. Gulf Coast. Prior researchers have revealed that the tornadic cells within tropical cyclone (TC) rainbands are often supercellular in character. The present study investigates the utility of several common midlatitude, continental supercell and tornado diagnostic tools when applied to Hurricane Ivan’s tornado episode.

The environment within Hurricane Ivan was favorable for storm rotation. While well offshore, the bands of Hurricane Ivan possessed embedded cells with mesocyclones of moderate intensity. A dual-Doppler analysis reveals that the updrafts of these cells were highly helical in the lower troposphere, suggesting significant ingestion of streamwise environmental vorticity. These coherent cells were long lived and could be tracked for multiple hours. As the supercells over the Gulf of Mexico approached the coast during Ivan’s landfall, rapid increases in midlevel vorticity and vertically integrated liquid (VIL) occurred. Based on compiled severe weather reports, these increases in storm intensity appear often to have immediately preceded tornadogenesis.

The local environment for supercells in Ivan’s interior is evaluated through the use of 62 soundings from the operational land-based network and from research flights. There were substantial differences in the thermodynamic profiles and wind profiles at differing ranges from Ivan’s center, from quadrant to quadrant of Ivan’s circulation, and between land and sea. The most optimal environment for supercells and tornadoes occurred in the most interior section of Ivan’s right-front quadrant, with conditions being even more favorable over land than over the sea. For contrast, comparable values are presented for Hurricane Jeanne (2004), which was similar to Ivan in several respects, but was not a prolific tornado producer at landfall. Although both storms provided environments with comparable shallow—and deep—layer vertical wind shear, the Ivan environment had notably more CAPE, likely due to a prominent dry air intrusion. This increase in CAPE was reflected in substantial increases in common operational forecasting composite indices. The results suggest that the conventionally assessed ingredients for midlatitude continental supercells and tornadoes can be readily applied to discriminate among TC tornado episodes.
Basic Studies for Modeling Complex Weft Knitted Fabric Structures Part IV: Geometrical Modeling of Miss Stitches
Authors: Kayacan Ozlem , Kurbak Arif
Published: August 2008

In this work a model of miss stitch and its effect on the plain knitted fabric structure are introduced for the first time, thus we present a pioneering basic work on knit and miss combinations. Photographs of knitted samples were taken and the assumptions of the model are based on these photographs. A geometrical model of this knit and miss combination is created and the model is drawn to scale. We show that these shapes are found to be exactly the same shapes as observed in real fabrics.
Particle Release from Woven Cellulosic Substrates
Authors: Manian Avinash P. , Lenninger Margit , Bechtold Thomas , Steinlechner Erik
Published: August 2008

The linting propensity of a woven cellulosic substrate is investigated as a function of substrate characteristics and of different parameters in the test environment. The results from the linting propensity tests parallel those observed in liquid—solid extraction processes, where solutes are extracted from a matrix of other insoluble solids by selective dissolution in a liquid. The equation quantifying solute extraction in such systems also proves to be a good fit for the linting propensities observed in this work. Hence, it maybe possible to regard linting phenomena as extraction processes and to use the equation quantifying solute extraction to predict substrate linting as a function of both substrate characteristics and the test environment.
Fiber Length Distribution in Cotton Processing: A Finite Mixture Distribution Model
Authors: Krifa Mourad
Published: August 2008

This paper introduces a new approach to modeling and parameterizing cotton fiber length distribution. The approach uses finite mixture models to derive a parametric expression of the fiber length probability density function. The model was applied to a multitude of empirical length distributions and proved to adequately parameterize the complex distribution patterns, as well as express the intrinsic and process-related factors determining their shape.
Culture and Aesthetic Preference: Comparing the Attention to Context of East Asians and Americans
Authors: Masuda Takahiko , Gonzalez Richard , Kwan Letty , Nisbett Richard E.
Published: August 2008

Prior research indicates that East Asians are more sensitive to contextual information than Westerners. This article explored aesthetics to examine whether cultural variations were observable in art and photography. Study 1 analyzed traditional artistic styles using archival data in representative museums. Study 2 investigated how contemporary East Asians and Westerners draw landscape pictures and take portrait photographs. Study 3 further investigated aesthetic preferences for portrait photographs. The results suggest that (a) traditional East Asian art has predominantly context-inclusive styles, whereas Western art has predominantly object-focused styles, and (b) contemporary members of East Asian and Western cultures maintain these culturally shaped aesthetic orientations. The findings can be explained by the relation among attention, cultural resources, and aesthetic preference.
Reduction of blood coagulation and monocyte-platelet interaction following the use of a minimal extracorporeal circulation system (Synergy®) in coronary artery bypass grafting (CABG)
Authors: Farneti PA , Sbrana S , Spiller D , Cerillo AG , Santarelli F , Di Dario D , Del Sarto PA , Glauber M
Published: August 2008

Cardiovascular surgery with cardiopulmonary bypass (CPB) induces activation of blood coagulation and systemic inflammation involved in post-operative complications. Our study evaluated the impact of the minimal extracorporeal circulation (mini-CPB) system (Synergy®, Sorin Group) on these functional aspects. Twenty patients were randomly assigned to standard CPB (n=10) or to Synergy (n=10). Platelet expression of PAC-1, and monocyte/granulocyte-platelet conjugates were evaluated by flow cytometry. A leukocyte-platelet adhesion index was calculated after cell number normalization. ELISAs were performed to measure IL-6 and TNF-α, thrombin-antithrombin III complexes (TAT), prothrombin fragments (F1+2), β-thromboglobulin (β-TG) and sP-selectin (sCD62P). Blood samples were drawn at the time of anesthesia (T1), at the end of CPB (T2), and at 4 (T3) and 24 hours (T4) after weaning from CPB. All patients were similar for clinical characteristics. When compared to standard CPB, the Synergy showed lower levels of the monocyte-platelet adhesion index at T2 (0.023 ± 0.005 vs 0.063 ± 0.013, P = 0.0092) and T4 (0.031 ± 0.003 vs 0.055 ± 0.005, P = 0.0017), TAT complexes at T2 (27.175 ± 5.967 vs 86.592 ± 5.415, P = 0.0005) and T3 (26.977 ± 2.468 vs 45.146 ± 4.365, P = 0.0041), F1+2 fragments at T2 (2.222 ± 0.226 vs 4.249 ± 0.292, P = 0.0009), and sP-selectin at T3 (115.17 ± 19.623 vs 169.554 ± 19.709, P = 0.0703) and T4 (108.542 ± 6.429 vs 140.799 ± 14.771, P = 0.0833). In summary, the Synergy exhibited a lower post-operative activation of blood coagulation, together with a reduced interaction between circulating monocytes and platelets.
Continous quality improvement of perfusion practice: the role of electronic data collection and statistical control charts
Authors: Baker RA , Newland RF
Published: August 2008

In-hospital data collection may be used to improve the selection, operative techniques, and process of care for cardiac surgical patients. The aim of this report is to demonstrate the influence of the automated generation of quality indicators (QI) for cardiopulmonary bypass (CPB) and the implementation of a continuous quality improvement (CQI) programme on the CPB process of care. Adult patients undergoing CPB were divided into three consecutive groups: Group 1 (n=363); no QI data feedback, Group 2 (n = 253); automated QI data feedback alone, and Group 3 (n = 363) data feedback and implementation of CQI. There were no significant differences in demographic, procedural or clinical outcomes for each group. Significant improvement, as determined by adherence to practice protocols and reduction in practice variation, was observed for cardiac index < 1.6 L/min/m2 (min), mean arterial pressure < 40 mmHg (min), venous saturation < 60% (min), arterial blood temperature of > 37.50C (min), minimum pCO2 (mmHg), maximum pCO2 (mmHg), and minimum pO2 (mmHg). There was no change in the minimum haemoglobin (g/dl) on bypass. Automated generation of QI resulted in improved adherence to process of care guidelines, highlighting the potential of electronic data collection. This technique is optimised in a CQI programme, utilising statistical control charts for data interpretation.
Clinical evaluation of the Admiral 1.35m2 hollow-fibre membrane oxygenator
Authors: Issitt R , Cumberland T , Clements A , Mulholland J
Published: August 2008

This prospective study was designed to evaluate the fundamental clinical performance of a new, small surface area oxygenator. Data were collected from twenty patients undergoing first-time coronary artery bypass grafting using this device. This study focuses on how the reduction of surface area and prime volume affects the essential function of the oxygenator in terms of oxygenation efficiency, heat transference, membrane pressure drops, haemolysis and safety. Oxygenation efficiency was deemed to be well within acceptable margins, even at high flows, over a temperature range of 32-36°C. Heat-exchanger performance was assessed by recording the heater/chiller water temperature compared to retrospective data from a current standard oxygenator. Heater/chiller water temperatures were on average 0.3°C higher with the small surface oxygenator than the standard data. The air handling of the device was excellent and extremely safe. Haemolysis, measured as plasma free haemoglobin, did not increase during bypass (p>0.05). This new oxygenator offers a reduced surface area and priming volume while still ensuring an acceptable safety reserve and performance.