bluuebunny/crossref_metadata_2025 huggingface dataset:
A Fuzzy Dynamic Programming Approach for the Mixed-Discrete Optimization of Mechanical Systems
Authors: Xiong Ying , Rao Singiresu S.
Published: October 2005

Many engineering optimization problems can be considered as multistage decision-making problems. If the system involves uncertainty in the form of linguistic parameters and vague data, a fuzzy approach is to be used for its description. The solution of such problems can be accomplished through fuzzy dynamic programming. However, most of the existing fuzzy dynamic programming algorithms cannot deal with mixed-discrete design variables in the optimization of mechanical systems containing fuzzy information. They often assumed that a fuzzy goal is imposed only on the final state for simplicity, the values of fuzzy goal and other parameters need to be predefined, and an optimal solution is obtained in the continuous design space only. To better reflect the nature of uncertainties present in real-life optimization problems, a mixed-discrete fuzzy dynamic programming (MDFDP) approach is proposed in this work for solving multistage decision-making problems in mixed-discrete design space with a fuzzy goal and a fuzzy state imposed on each stage. The method can also be extended to solve general mixed-discrete fuzzy nonlinear programming problems if their corresponding crisp problems can be solved using dynamic programming approaches. The feasibility and versatility of the proposed method are illustrated by considering the design of a four-bar truss and the reliability-based optimization of a gearbox. To the authors’ knowledge, this work represents the first fuzzy dynamic programming method reported in the literature for dealing with mixed-discrete optimization problems.
A Hybrid Genetic Algorithm for Mixed-Discrete Design Optimization
Authors: Rao Singiresu S. , Xiong Ying
Published: October 2005

A new hybrid genetic algorithm is presented for the solution of mixed-discrete nonlinear design optimization. In this approach, the genetic algorithm (GA) is used mainly to determine the optimal feasible region that contains the global optimum point, and the hybrid negative subgradient method integrated with discrete one-dimensional search is subsequently used to replace the GA to find the final optimum solution. The hybrid genetic algorithm, combining the advantages of random search and deterministic search methods, can improve the convergence speed and computational efficiency compared with some other GAs or random search methods. Several practical examples of mechanical design are tested using the computer program developed. The numerical results demonstrate the effectiveness and robustness of the proposed approach.
Compensation and Weights for Trade-offs in Engineering Design: Beyond the Weighted Sum
Authors: Scott Michael J. , Antonsson Erik K.
Published: October 2005

Multicriteria decision support methods are common in engineering design. These methods typically rely on a summation of weighted attributes to accomplish trade-offs among competing objectives. It has long been known that a weighted sum, when used for multicriteria optimization, may fail to locate all points on a nonconvex Pareto frontier. More recent results from the optimization literature relate the curvature of an objective function to its ability to capture Pareto points, but do not consider the significance of the objective function parameters in choosing one Pareto point over another. A parametrized family of aggregations appropriate for engineering design is shown to model decisions capturing all possible trade-offs, and therefore can direct the solution to any Pareto optimum. This paper gives a mathematical and theoretical interpretation of the parameters of this family of aggregations as defining a degree of compensation among criteria as well as a measure of their relative importance. The inability to reach all Pareto optima is shown to be surmounted by this consideration of degree of compensation as an additional parameter of the decision. Additionally, the direct specification of importance weights is common to many decision methods. The choice of a single point from a Pareto frontier by specifying importance weights alone is shown to depend on the degree of compensation implicit in the aggregation. Thus both the degree of compensation and weights must be considered to capture all potentially acceptable decisions. A simple truss design example is used here to illustrate the concepts.
Kinematic and Static Analyses of Tripod Constant Velocity Joints of the Spherical End Spider Type
Authors: Watanabe Katsumi , Kawakatsu Tsutomu , Nakao Shouichi
Published: October 2005

The closed-loop equations of three cylindrical rollers, the spider of three spherical ends, and the housing of the tripod constant velocity joints are deduced as the spatial mechanism. They are solved for prescribed positions of its input, and output shafts and relative motion characteristics of components are made clear. Moreover, a procedure is established for solving, simultaneously, the set of conditional equations with respect to forces and moments acting on three cylindrical rollers, the spider, and the housing, for any values of friction coefficients between cylindrical rollers and its grooves and spherical ends. The established numerical procedure simulates the normal force acting on the roller groove with a period of π and the housing thrust force with a period of 2π∕3 for given values of the joint angle. These results are inspected by experiments.
Kinematic, Static, and Dynamic Analysis of a Planar One-Degree-of-Freedom Tensegrity Mechanism
Authors: Arsenault Marc , Gosselin Clément M.
Published: October 2005

The use of tensegrity systems as structures has been extensively studied. However, their development for use as mechanisms is quite recent even though they present such advantages as reduced mass and a deployment capability. The object of this paper is to apply analysis methods usually reserved for conventional mechanisms to a planar one-degree-of-freedom tensegrity mechanism. This mechanism is obtained from a three-degree-of-freedom tensegrity system by adding actuation to the latter as well as by making some assumptions of symmetry. Analytical solutions are thus developed for the mechanism’s direct and inverse static problems. Furthermore, the working curve, singularities, and stiffness of the mechanism are detailed. Finally, a dynamic model of the mechanism is developed and a preliminary control scheme is proposed.
Coupler Cognates for the Double Flier Eight-Bar Linkage
Authors: Pennock Gordon R. , Raje Nihar N.
Published: October 2005

This paper presents a graphical technique to construct the coupler cognate linkages for the double flier eight-bar linkage. The technique is based on the skew pantograph construction which converts the double flier linkage into a second eight-bar linkage by applying the concepts of stretch rotation and kinematic inversion. Since a stretch-rotation operation preserves the angular velocities of corresponding links of the two linkages then the second linkage has the same input-output motion as the original double flier linkage. Another stretch rotation is performed on the intermediate eight-bar linkage and a third eight-bar linkage, which duplicates the motion of the coupler link of the original linkage, is obtained. This graphical approach, to investigating coupler cognates, is believed to be an original contribution to the study of cognate linkages. The technique can be applied in a straightforward manner, requiring few constructions, and offers significant advantages over well-known analytical techniques which use the locus equation. For the double flier eight-bar linkage, the locus equation is of a high degree and the coefficients can only be obtained from a very laborious procedure. This paper shows the existence of two coupler cognates for each of the two floating binary links of the double flier eight-bar linkage that are connected to the ternary link which is pinned to ground.
Express Model for Load Sharing and Stress Analysis in Helical Gears
Authors: Guilbault Raynald , Gosselin Claude , Cloutier Louis
Published: October 2005

The performance of a gear set is strongly influenced by the manufacturing and assembly quality. Therefore, detailed analyses at the design stage, where the effects of expected assembly and manufacturing errors can be simulated, are crucial. At an early design stage, when contact conditions are addressed, the widely used finite element method (FEM) may still result in unwanted computing time. The paper presents an Express model developed to serve as a fast design tool offering fine simulation and a high precision level. The model establishes load sharing, fillet stresses and pressure distribution along the contacting surfaces of meshing helical gear teeth. The calculations combine the finite strip method with a pseudo-three-dimensional (3D) model of the tooth base solved with finite differences to calculate tooth bending deflexion and fillet stresses. The accuracy of the procedure is demonstrated through 3D FEM models. A contact cell discretization completes the model. This very fast and accurate approach gives the contact pressure distributions resulting from the roll-slide motion of mating teeth. An analysis of a helical gear set in two different assembly positions reveals the effects of edge contact, and exhibits the influence of tooth stiffness reduction near tooth corners.
Reliability-Based Design With the Mixture of Random and Interval Variables
Authors: Du Xiaoping , Sudjianto Agus , Huang Beiqing
Published: October 2005

In reliability-based design (RBD), uncertainties are usually treated stochastically, and nondeterministic variables are assumed to follow certain probability distributions. However, in many practical engineering applications, distributions of some random variables may not be precisely known or uncertainties may not be appropriately represented with distributions. The possible values of those nondeterministic variables are often only known to lie within specified intervals without precise distribution information. In this paper, we attempt to address this issue by proposing a RBD method to deal with the uncertain variables characterized by the mixture of probability distributions and intervals. The reliability is considered under the condition of the worst case combination of interval variables. The computational demand of RBD with the mixture of random and interval variables may increase dramatically due to the need for identifying the worst case interval variables. To alleviate the computational burden, a sequential single-loop procedure is employed to replace the computationally expensive double-loop procedure when the worst case scenario is applied directly. With the proposed method, the RBD is conducted within a series of cycles of deterministic optimization and reliability analysis. The optimization model in each cycle is built based on the most probable point under the worst case combination of the interval variables obtained from the reliability analysis in the previous cycle. Since the optimization is decoupled from the probabilistic analysis, the computational amount for reliability analysis is decreased to the minimum extent. The proposed method is demonstrated with two examples.
Dynamic Formulation and Performance Comparison of the 3-DOF Modules of Two Reconfigurable PKM—the Tricept and the TriVariant
Authors: Li Meng , Huang Tian , Mei Jiangping , Zhao Xueman , Chetwynd Derek G. , Hu S. Jack
Published: October 2005

Utilizing the virtual work principle, this paper presents a method for the inverse dynamic formulation of the 3-degree-of-freedom (DOF) modules of the well-known Tricept robot and a newly invented hybrid robot named TriVariant. The TriVariant is a modified version of the Tricept, achieved by integrating one of the three active limbs into the passive one. Both local and global conditioning indices are proposed for the dynamic performance evaluation and comparison of these two robots. These indices are designed on the basis of the maximum actuated joint force required for producing a unit acceleration of the mobile platform. For a given set of geometrical and inertial parameters, it has been shown that the TriVariant has a similar overall dynamic performance compared with that of the Tricept.
Stress Analysis of Near Optimal Surface Notches in 3D Plates
Authors: Wescott R. , Semple B. , Heller M.
Published: October 2005

This paper presents a method of using two-dimensional (2D) optimal notch shapes to create near optimal surface notches with various depth and aspect ratios in uniaxially loaded three-dimensional (3D) plates. Axisymmetric and elongated surface notches are created by rotating 2D optimal notch shapes about two types of fixed axes, a major reason being to enable the surface notches to be manufactured by elementary methods. Stresses in the surface notches are determined using intensive 3D finite element analyses. Axisymmetric notches show small reductions in local peak stress relative to spherical notches with the same bounding dimensions. Local peak stresses in elongated notches are reduced by up to 26% relative to comparable spherical notches. The given method and results are transferable for the initial design, re-shaping, and damage repair of components manufactured from any commonly used metal. In damage removal applications a significant advantage of both notch types over spherical notches is that they allow more material to be extracted for the same notch length and maximum depth.
Statistical Mesomechanics of Solid, Linking Coupled Multiple Space and Time Scales
Authors: Bai Y. L. , Wang H. Y. , Xia M. F. , Ke F. J.
Published: October 2005

This review begins with the description of a new challenge in solid mechanics: multiphysics and multiscale coupling, and its current situations. By taking spallation as an example, it is illustrated that the fundamental difficulty in these multiscale nonequilibrium problems is due to the hierarchy and evolution of microstructures with various physics and rates at various length levels in solids. Then, some distinctive thoughts to pinpoint the obstacles and outcome are outlined. Section 3 highlights some paradigms of statistical averaging and new thoughts to deal with the problems involving multiple space and time scales, in particular the nonequilibrium damage evolution to macroscopic failure. In Sec. 4, several frameworks of mesomechanics linking multiple space and time scales, like dislocation theory, physical mesomechanics, Weibull theory, and stochastic theory, are briefly reviewed and the mechanisms underlying the trans-scale coupling are elucidated. Then we turn to the frameworks mainly concerning damage evolution in Sec. 5, namely, statistical microdamage mechanics and its trans-scale approximation. Based on various trans-scale frameworks, some possible mechanisms governing the trans-scale coupling are reviewed and compared in Sec. 6. Since the insight into the very catastrophic transition at failure is closely related to strong trans-scale coupling, some new concepts on nonequilibrium and strong interaction are discussed in Sec. 7. Finally, this review is concluded with a short summary and some suggestions. “This review article cites 130 references.”
Design of Irregular Slider Surface for Satisfying Specified Load Demands
Authors: Cheng Chin-Hsiang , Chang Mei-Hsia
Published: October 2005

This study is to design the surfaces of sliders to meet the pressure distribution specified by the designers. The slider surfaces, in general, characterize an irregular profile. A direct problem solver, which is able to provide solutions for pressure distribution in the air film between the slider and the moving surface for various geometric conditions, is incorporated with an inverse method for determination of slider surface shape. In this report, a point-by-point design method is developed to improve the polynomial-function approach proposed in an earlier study (Cheng and Chang, 2004, J. of Tribology 126, pp. 519-526.) An exact solution for the two-dimensional design problems has also been developed to partly confirm the present approach. Results obtained from the present approaches are demonstrated by a comparison with the data from the existing method and the exact solutions to display the relative performance of the present method. The desired slider-shape design is a function of the bearing numbers. The slider shapes associated with different combinations of bearing numbers are investigated.
Analysis of Cord-Reinforced Poly-Rib Serpentine Belt Drive With Thermal Effect
Authors: Song G. , Chandrashekhara K. , Breig W. F. , Klein D. L. , Oliver L. R.
Published: October 2005

This paper investigates the operation of an automotive poly-rib serpentine belt system. A three-dimensional dynamic finite element model, consisting of a driver pulley, a driven pulley, and a complete five-rib V-ribbed belt, was created. Belt construction accounts for three different elastomeric compounds and a single layer of reinforcing cords. Rubber was considered incompressible hyperelastic material, and cord was considered linear elastic material. The material model accounting for thermal strains and temperature-dependent properties of the rubber solids was implemented in ABAQUS∕EXPLICIT code for the simulation. A tangential shear angle and an axial shear angle were defined to quantify shear deformations. The shear angles were found to be closely related to velocity variation along contact arc and the imbalanced contact stress distribution on different sides of the same rib and on different ribs. The temperature effect on shear deformation, tension and velocity variation, and contact stress distribution was investigated and shown in comparison to the results for the same system operating at room temperature.
Comparative Evaluation of Finite Element Models and Types of Analyses for a Bolted Joint
Authors: Padmaja R. , Rao R. Ravinder , Kotiveerachari B. , Godbole P. B.
Published: October 2005

The present work is aimed at evaluating different ways in which a given joint can be analyzed using the Finite Element Method. The bolt is modeled using line elements (link) or area elements (continuum) and a comparative evaluation is carried out. Each of these types is further subdivided into three categories viz., plane stress, axisymmetric, and three-dimensional models. Thus a total of six models are proposed to be analyzed and compared. As the bolt shares only a small fraction of external load in a well-tightened joint, the relative flexibility of a bracket is also studied as an example in the present work. Comparing the results of these analyses it was found that the type of model used for the bolt is more important than the type of analysis. This aspect is probed further to find the essential difference between bolt as link and bolt as continuum. The analysis is carried out using ANSYS, which enables writing many parametric programs.
Patenting and Licensing of University-Based Genetic Inventions – A View from Experience at Stanford University’s Office of Technology Licensing
Authors: Leute Kirsten
Published: October 2005

University technology transfer offices license inventions created at universities to companies looking for tools, additions to their product pipelines, improvements or start-up opportunities. This paper will cover the motivations for conducting university technology transfer, an overview of Stanford’s Office of Technology Licensing and its patenting and licensing practices, models of royalty sharing at university technology transfer offices, and patenting and licensing genetic information inventions at Stanford University. The terms ‘invention’ and ‘technology’ are used interchangeably throughout the paper.
Phosphorylation of Neuronal and Endothelial Nitric Oxide Synthase in the Kidney with High and Low Salt Diets
Authors: Mount Peter F. , Fraser Scott A. , Watanabe Yasuo , Lane Natalie , Katsis Frosa , Chen Zhi-Ping , Kemp Bruce E. , Power David A.
Published: October 2005

Background: Renal nitric oxide (NO) synthesis increases with increasing salt intake, however, the mechanisms underlying this are poorly understood. We hypothesized that activating or inhibitory phosphorylation of neuronal and endothelial nitric oxide synthase (nNOS, eNOS) regulates renal NO production in response to altered dietary salt. Methods:Sprague-Dawley rats were fed low, normal or high salt diets for 12 h or 2 weeks, and kidney NOS phosphorylation was analyzed by Western blot using phosphopeptide antibodies against the sites nNOS-Ser1412, nNOS-Ser847, eNOS-Ser1176 and eNOS-Thr494. Results:At 12 h, total nNOS increased 1.4-fold (p < 0.01) in the high salt group and decreased by 26% (p < 0.05) in the low salt group. Changes in expression of phospho-nNOS at 12 h were accounted for by the changes in total nNOS. No change in total or phospho-eNOS was seen at 12 h. At 2 weeks, in the low salt group expression of total nNOS increased 1.8-fold (p < 0.05) whereas expression of nNOS phosphorylated at the inhibitory site Ser847 increased 4.3-fold (p < 0.01). Total eNOS was increased 3-fold in the low salt group (p < 0.01), with parallel increases in eNOS phosphorylated at both activating and inhibitory sites (p < 0.05). In the 2-week high salt group no changes in NOS expression or phosphorylation were seen, despite the observed increased excretion of urinary NO metabolites. Conclusion:In summary, changes in phospho-nNOS and phospho-eNOS expression occurred in parallel with changes in total expression, thus, the overall activating and inhibitory effects of nNOS and eNOS phosphorylation at the sites studied were not changed by altered dietary salt.
The Comparative Morphology of the Cerebellum in Caprimulgiform Birds: Evolutionary and Functional Implications
Authors: Iwaniuk Andrew N. , Hurd Peter L. , Wylie Douglas R.W.
Published: October 2005

Interspecific variation in the structure of the avian cerebellum is poorly understood. We present the first comparison of cerebellar morphology within the avian order Caprimulgiformes. Using a range of qualitative descriptions and quantitative measurements of cerebellar morphology we compared caprimulgiform birds with hummingbirds and swifts (Apodiformes) and owls (Strigiformes), two groups that are putative sister taxa to the Caprimulgiformes. Our results demonstrate that the owlet-nightjars (Aegothelidae), nightjars (Caprimulgidae) and potoos (Nyctibiidae) are more similar to apodiforms than they are to other taxa. All of these species have a reduced anterior lobe characterized by particularly small folia II and III and a relatively large posterior lobe. The frogmouths (Podargidae) possess a markedly different cerebellum that is more similar to that of owls than any of the caprimulgiform or apodiform birds. The monotypic oilbird (Steatornis caripensis, Steatornithidae) possesses a cerebellum with some nightjar-like features and some owl-like features, but overall it too resembles an owl more than a nightjar. This cerebellar diversity within the order Caprimulgiformes has significant implications for understanding the evolutionary relationships within the order, how the avian cerebellum has evolved and whether interspecific differences in cerebellar morphology reflect behavior.
Novel Drug Delivery Systems: Potential in Improving Topical Delivery of Antiacne Agents
Authors: Date A.A. , Naik B. , Nagarsenker M.S.
Published: October 2005

Acne is the most common cutaneous disorder of multifactorial origin with a prevalence of 70–85% in adolescents. The majority of the acne sufferers exhibit mild to moderate acne initially, which progresses to the severe form in certain cases. Topical therapy is employed as first-line treatment in mild acne, whereas for moderate and severe acne, systemic therapy is required in addition to topical therapy. Currently, several topical agents are available that affect at least one of the main pathogenetic factors responsible for the development of acne. Although topical therapy has an important position in acne treatment, side effects associated with various topical antiacne agents and the undesirable physicochemical characteristics of certain important agents like tretinoin and benzoyl peroxide affect their utility and patient compliance. Novel drug delivery strategies can play a pivotal role in improving the topical delivery of antiacne agents by enhancing their dermal localization with a concomitant reduction in their side effects. The current review emphasizes the potential of various novel drug delivery strategies like liposomes, niosomes, aspasomes, microsponges, microemulsions, hydrogels and solid lipid nanoparticles in optimizing and enhancing the topical delivery of antiacne agents.
Parameterization of Canopy Structure and Leaf-Level Gas Exchange for an Eastern Amazonian Tropical Rain Forest (Tapajós National Forest, Pará, Brazil)
Authors: Domingues Tomas F. , Berry Joseph A. , Martinelli Luiz A. , Ometto Jean P. H. B. , Ehleringer James R.
Published: October 2005

Carbon flux of Amazonian primary forest vegetation has been shown to vary both spatially and temporally. Process-based models are adequate tools to understand the basis of such variation and can also provide projections to future scenarios. The parameterization of such process-based models requires information from the vegetation in question simply because ecosystem-level gas exchange is a direct result of the tightly coupled interaction between local vegetation and regional climate. In this study, data are presented concerning canopy structure [leaf area index (LAI), and the ratio of leaf dry mass to leaf area (LMA)], leaf chemistry [area-based foliar nitrogen content (Narea) and carbon isotope composition (δ13C)], and photosynthetic gas exchange [maximum carbon assimilation rates (Amax), stomatal conductance (gs@Amax), maximum carboxylation capacity (Vcmax), and respiration rates (Rd)] versus relative height from an extensive survey of primary forest vegetation of the Santarém region (eastern Amazon, Santarém, Federal State of Pará, Brazil). Ground-level LAI values ranged between 4.5 and 5.9. Both Amax and Vcmax showed large variations within the canopy profile with values ranging between 2.4 and 15.7 μmol m−2 s−1 and between 10.1 and 105.7 μmol m−2 s−1, respectively. Also, Narea varied between 0.75 to 4.19 gN m−2, and similar to Amax and Vcmax, showed higher values at the top of the canopy. Variations were detected among sites in patterns of vertical distribution of Narea and LAI, indicating spatial heterogeneity of the forest. Also, no statistically significant evidence of seasonal variations on parameters was observed, indicating that there is limited gas exchange acclimation by the vegetation to wet or dry seasons.
Quality Control and Verification of Weather Radar Wind Profiles
Authors: Holleman Iwan
Published: October 2005

Weather radar wind profiles (WRWPs) have been retrieved from Doppler volume scans using different implementations of the velocity–azimuth display (VAD) and volume velocity processing (VVP) methods. An extensive quality control of the radial velocity data and the retrieved wind vectors has been applied. The quality and availability of the obtained wind profiles have been assessed by comparisons with collocated radiosonde observations and numerical weather prediction (NWP) data over a 9-month period. The comparisons reveal that the VVP methods perform better than the VAD methods, and that the simplest implementation of the VVP (VVP1) method performs the best of all. The availability fraction of VVP1 wind vectors is about 0.39 at ground level and drops below 0.16 at a 6-km altitude. The observation minus background statistics of the VVP1 wind profiles against the High Resolution Limited Area Model (HIRLAM) NWP model are at least as good as those of the radiosonde profiles. This result clearly demonstrates the high quality of (quality controlled) weather radar wind profiles.
Using a Blackbody to Calculate Net Longwave Responsivity of Shortwave Solar Pyranometers to Correct for Their Thermal Offset Error during Outdoor Calibration Using the Component Sum Method
Authors: Reda I. , Hickey J. , Long C. , Myers D. , Stoffel T. , Wilcox S. , Michalsky J. J. , Dutton E. G. , Nelson D.
Published: October 2005

Thermopile pyranometers’ thermal offset has been recognized since the pyranometer’s inception. This offset is often overlooked or ignored because its magnitude is small compared to the overall solar signal at higher irradiance. With the demand of smaller uncertainty in measuring solar radiation, recent publications have described a renewed interest in this offset, its magnitude, and its effect on solar measurement networks for atmospheric science and solar energy applications. Recently, it was suggested that the magnitude of the pyranometer thermal offset is the same if the pyranometer is shaded or unshaded. Therefore, calibrating a pyranometer using a method known as the shade/unshade method would result in accurate responsivity calculations because the thermal offset error is canceled. When using the component sum method for the pyranometer calibration, the thermal offset error, which is typically negative when the sky is cloudless, does not cancel, resulting in an underestimated shortwave responsivity. Most operational pyranometers that are in use for solar radiation measuring networks are calibrated using the component sum method since it is possible to calibrate many pyranometers simultaneously. From this arises the importance of correcting the component sum method results to account for the thermal offset error.

In this article a method of using a blackbody system to calculate the net longwave responsivity of pyranometers, which is largely responsible for the offset error, is described. This longwave responsivity is then used to correct the pyranometer’s shortwave responsivity during the component sum method calibrations and thereby substantially reduces the effect of the offset error on the final pyranometer responsivity. Practical procedures for performing this calibration procedure along with its limitations and remaining uncertainties are given.
Estimating Internal Wave Energy Fluxes in the Ocean
Authors: Nash Jonathan D. , Alford Matthew H. , Kunze Eric
Published: October 2005

Energy flux is a fundamental quantity for understanding internal wave generation, propagation, and dissipation. In this paper, the estimation of internal wave energy fluxes 〈u′p′〉 from ocean observations that may be sparse in either time or depth are considered. Sampling must be sufficient in depth to allow for the estimation of the internal wave–induced pressure anomaly p′ using the hydrostatic balance, and sufficient in time to allow for phase averaging. Data limitations that are considered include profile time series with coarse temporal or vertical sampling, profiles missing near-surface or near-bottom information, moorings with sparse vertical sampling, and horizontal surveys with no coherent resampling in time. Methodologies, interpretation, and errors are described. For the specific case of the semidiurnal energy flux radiating from the Hawaiian ridge, errors of ∼10% are typical for estimates from six full-depth profiles spanning 15 h.
Impact of Combining Temperature Profiles from Different Instruments on an Analysis of Mixed Layer Properties
Authors: Schmid Claudia
Published: October 2005

For a joint analysis of temperature profiles from floats, expendable bathythermographs (XBTs), and other instruments (e.g., thermistor chains) the consistency of the profiles from the different sources needs to be ensured to avoid results with systematic errors. In this study profiles from the different instrument types are compared after they passed through a series of quality control tests. The different methods for quality control are presented. After ensuring that only high-quality profiles remain in the dataset, a statistical analysis of the temperature differences between adjacent profiles (in space and time) is performed. Potential regional differences as well as possible differences between the various float types are addressed. Finally, the impact of combining the profiles from floats with those from other instruments on gridded fields of the mixed layer temperature, thickness, and heat budget is discussed. It is found that the joint analysis yields more reliable results for the gridded fields and the heat storage rate. A large part of this improvement is a result of the reduced seasonal bias.
Sensitivity Analysis of Quality Assurance Using the Spatial Regression Approach—A Case Study of the Maximum/Minimum Air Temperature
Authors: Hubbard Kenneth G. , You Jinsheng
Published: October 2005

Both the spatial regression test (SRT) and inverse distance weighting (IDW) methods have been applied to provide estimates for the maximum air temperature (Tmax) and the minimum air temperature (Tmin) in the Applied Climate Information System (ACIS). This is critical to the processes of estimating missing data and identifying suspect data and is undertaken here to ensure quality data in ACIS. The SRT method was previously found to be superior to the IDW method; however, the sensitivity of the performance of both methods to input parameters has not been evaluated. A set of analyses is presented for both methods whereby the sensitivity to the radius of inclusion, the regression time window, the regression time offset, and the number of stations used to make the estimates are examined. Comparisons were also conducted between the SRT and the IDW methods. The performance of the SRT method stabilized when 10 or more stations were applied in the estimates. The optimal number of stations for the IDW method varies from only a few to 30. The results indicate that the best estimates obtained using the IDW method are still inferior to the worst estimates obtained using the SRT method.
TURAC—A New Instrument Package for Radiation Budget Measurements and Cloud Detection
Authors: Ruckstuhl C. , Philipona R.
Published: October 2005

Atmospheric radiation flux measurements and the resulting surface radiation budget are important quantities for greenhouse effect and climate change investigations. Accurate net shortwave and longwave fluxes, in conjunction with numerical algorithms, also allow monitoring of the radiative effect of clouds and the nowcasting of the cloud amount. To achieve certain advantages on the accuracy of flux measurements a new instrument is developed that measures downward and upward shortwave and longwave radiation with the same sensors. Two high-quality instruments—a pyranometer for shortwave and a pyrgeometer for longwave measurements—are mounted on a pivotable sensor head, which is rotated up and down in 10-min intervals. To keep the instrument domes free from dew and ice, and to minimize the pyranometer thermal offset, both sensors are ventilated with slightly heated air. Additionally, a ventilated temperature and humidity sensor is integrated in the new instrument. The combination of measurements of radiation fluxes, temperature, and humidity allows for instrument use for autonomous and automatic cloud amount detection. The Temperature, Humidity, Radiation and Clouds (TURAC) sensor has been successfully tested under harsh alpine winter conditions, as well as under moderate lowland conditions. Comparisons to reference instruments showed all radiation fluxes to be within a maximum bias and rms difference of 1.6% or 1.4 W m−2 on daily averages.
Multi-PRI Signal Processing for the Terminal Doppler Weather Radar. Part II: Range–Velocity Ambiguity Mitigation
Authors: Cho John Y. N.
Published: October 2005

Multiple pulse-repetition interval (multi-PRI) transmission is part of an adaptive signal transmission and processing algorithm being developed to combat range–velocity (RV) ambiguity for the Terminal Doppler Weather Radar (TDWR). In Part I of this two-part paper, an adaptive clutter filtering procedure that yields low biases in the moments estimates was presented. In this part, algorithms for simultaneously providing range-overlay protection and velocity dealiasing using multi-PRI signal transmission and processing are presented. The effectiveness of the multi-PRI RV ambiguity mitigation scheme is demonstrated using simulated and real weather radar data, with excellent results. Combined with the adaptive clutter filter, this technique will be used within the larger context of an adaptive signal transmission and processing scheme in which phase-code processing will be a complementary alternative.
Use of Dual-Wavelength Radar for Snow Parameter Estimates
Authors: Liao Liang , Meneghini Robert , Iguchi Toshio , Detwiler Andrew
Published: October 2005

Use of dual-wavelength radar, with properly chosen wavelengths, will significantly lessen the ambiguities in the retrieval of microphysical properties of hydrometeors. In this paper, a dual-wavelength algorithm is described to estimate the characteristic parameters of the snow size distributions. An analysis of the computational results, made at X and Ka bands (T-39 airborne radar) and at S and X bands (CP-2 ground-based radar), indicates that valid estimates of the median volume diameter of snow particles, D0, should be possible if one of the two wavelengths of the radar operates in the non-Rayleigh scattering region. However, the accuracy may be affected to some extent if the shape factors of the gamma distribution used for describing the particle distribution are chosen far from the true values or if cloud water attenuation is significant. To examine the validity and accuracy of the dual-wavelength radar algorithms, the algorithms are applied to the data taken from the Convective and Precipitation-Electrification Experiment (CaPE) in 1991, in which the dual-wavelength airborne radar was coordinated with in situ aircraft particle observations and ground-based radar measurements. Having carefully coregistered the data obtained from the different platforms, the airborne radar-derived size distributions are then compared with the in situ measurements and ground-based radar. Good agreement is found for these comparisons despite the uncertainties resulting from mismatches of the sample volumes among the different sensors as well as spatial and temporal offsets.
Ethnic variations in incidence of asthma episodes in England & Wales:national study of 502,482 patients in primary care
Authors: Netuveli Gopalakrishnan , Hurwitz Brian , Sheikh Aziz
Published: October 2005

Background

Recent studies have demonstrated marked international variations in the prevalence of asthma, but less is known about ethnic variations in asthma epidemiology within individual countries and in particular the impact of migration on risk of developing asthma. Recent within country comparisons have however revealed that despite originating from areas of the world with a low risk for developing asthma, South Asian and Afro-Caribbean people in the UK are significantly (3× and 2× respectively) more likely to be admitted to hospital for asthma related problems than Whites.

Methods

Using data from the Fourth National Study of Morbidity Statistics in General Practice, a one-percent broadly representative prospective cohort study of consultations in general practice, we investigated ethnic variations in incident asthma consultations (defined as new or first consultations), and compared consultation rates between those born inside and outside the UK (migrant status). Logistic regression models were used to examine the combined effects of ethnicity and migration on asthma incident consultations.

Results

Results showed significantly lower new/first asthma consultation rates for Whites than for each of the ethnic minority groups studied (mean age-adjusted consultation rates per 1000 patient-years: Whites 26.4 (95%CI 26.4, 26.4); South Asians 30.4 (95%CI 30.3, 30.5); Afro-Caribbeans 35.1 (95%CI 34.9, 35.3); and Others 27.8 (27.7, 28.0). Within each of these ethnic groups, those born outside of the UK showed consistently lower rates of incident asthma consultations. Modelling the combined effects of ethnic and migrant status revealed that UK-born South Asians and Afro-Caribbeans experienced comparable risks for incident GP consultations for asthma to UK-born Whites. Non-UK born Whites however experienced reduced risks (adjusted OR 0.82, 95%CI 0.69, 0.97) whilst non-UK born South Asians experienced increased risks (adjusted OR 1.33, 95%CI 1.04, 1.70) compared to UK-born Whites.

Conclusion

These findings strongly suggest that ethnicity and migration have significant and independent effects on asthma incidence. The known poorer asthma outcomes in UK South Asians and Afro-Caribbeans may in part be explained by the offspring of migrants experiencing an increased risk of developing asthma when compared to UK-born Whites. This is the first study to find heterogeneity for incident asthma consultations in Whites by migrant status.
Substrate specificity analysis of protein kinase complex Dbf2-Mob1 by peptide library and proteome array screening
Authors: Mah Angie S , Elia Andrew EH , Devgan Geeta , Ptacek Jason , Schutkowski Mike , Snyder Michael , Yaffe Michael B , Deshaies Raymond J
Published: October 2005

Background

The mitotic exit network (MEN) is a group of proteins that form a signaling cascade that is essential for cells to exit mitosis in Saccharomyces cerevisiae. The MEN has also been implicated in playing a role in cytokinesis. Two components of this signaling pathway are the protein kinase Dbf2 and its binding partner essential for its kinase activity, Mob1. The components of MEN that act upstream of Dbf2-Mob1 have been characterized, but physiological substrates for Dbf2-Mob1 have yet to be identified.

Results

Using a combination of peptide library selection, phosphorylation of opitmal peptide variants, and screening of a phosphosite array, we found that Dbf2-Mob1 preferentially phosphorylated serine over threonine and required an arginine three residues upstream of the phosphorylated serine in its substrate. This requirement for arginine in peptide substrates could not be substituted with the similarly charged lysine. This specificity determined for peptide substrates was also evident in many of the proteins phosphorylated by Dbf2-Mob1 in a proteome chip analysis.

Conclusion

We have determined by peptide library selection and phosphosite array screening that the protein kinase Dbf2-Mob1 preferentially phosphorylated substrates that contain an RXXS motif. A subsequent proteome microarray screen revealed proteins that can be phosphorylated by Dbf2-Mob1 in vitro. These proteins are enriched for RXXS motifs, and may include substrates that mediate the function of Dbf2-Mob1 in mitotic exit and cytokinesis. The relatively low degree of sequence restriction at the site of phosphorylation suggests that Dbf2 achieves specificity by docking its substrates at a site that is distinct from the phosphorylation site
Identification of genes involved in Ca2+ ionophore A23187-mediated apoptosis and demonstration of a high susceptibility for transcriptional repression of cell cycle genes in B lymphoblasts from a patient with Scott syndrome
Authors: Kozian Detlef , Proulle Valérie , Nitsche Almut , Galitzine Marie , Martinez Marie-Carmen , Schumann Beatrice , Meyer Dominique , Herrmann Matthias , Freyssinet Jean-Marie , Kerbiriou-Nabias Danièle
Published: October 2005

Background

In contrast to other agents able to induce apoptosis of cultured cells, Ca2+ionophore A23187 was shown to elicit direct activation of intracellular signal(s). The phenotype of the cells derived from patients having the hemorrhagic disease Scott syndrome, is associated with an abnormally high proportion of apoptotic cells, both in basal culture medium and upon addition of low ionophore concentrations in long-term cultures. These features are presumably related to the mutation also responsible for the defective procoagulant plasma membrane remodeling. We analyzed the specific transcriptional re-programming induced by A23187 to get insights into the effect of this agent on gene expression and a defective gene regulation in Scott cells.

Results

The changes in gene expression upon 48 hours treatment with 200 nM A23187 were measured in Scott B lymphoblasts compared to B lymphoblasts derived from the patient's daughter or unrelated individuals using Affymetrix microarrays. In a similar manner in all of the B cell lines, results showed up-regulation of 55 genes, out of 12,000 represented sequences, involved in various pathways of the cell metabolism. In contrast, a group of 54 down-regulated genes, coding for histones and proteins involved in the cell cycle progression, was more significantly repressed in Scott B lymphoblasts than in the other cell lines. These data correlated with the alterations of the cell cycle phases in treated cells and suggested that the potent effect of A23187 in Scott B lymphoblasts may be the consequence of the underlying molecular defect.

Conclusion

The data illustrate that the ionophore A23187 exerts its pro-apoptotic effect by promoting a complex pattern of genetic changes. These results also suggest that a subset of genes participating in various steps of the cell cycle progress can be transcriptionally regulated in a coordinated fashion. Furthermore, this research brings a new insight into the defect in cultured Scott B lymphoblasts, leading to hypothesize that a mutated gene plays a role not only in membrane remodeling but also in signal transduction pathway(s) leading to altered transcriptional regulation of cell cycle genes.
Systemic and local antibiotic prophylaxis in the prevention of Staphylococcus epidermidisgraft infection
Authors: Turgut Huseyin , Sacar Suzan , Kaleli Ilknur , Sacar Mustafa , Goksin Ibrahim , Toprak Semra , Asan Ali , Cevahir Nural , Tekin Koray , Baltalarli Ahmet
Published: October 2005

Background

The aim of the study was to investigate the in vivo efficacy of local and systemic antibiotic prophylaxis in the prevention ofStaphylococcus (S.) epidermidisgraft infection in a rat model and to evaluate the bacterial adherence to frequently used prosthetic graft materials.

Methods

Graft infections were established in the subcutaneous tissue of 120 male Wistar rats by implantation of Dacron/ePTFE grafts followed by topical inoculation with 2 × 107CFUs of clinical isolate of methicillin-resistantS. epidermidis. Each of the graft series included a control group, one contaminated group that did not receive any antibiotic prophylaxis, two contaminated groups that received systemic prophylaxis with teicoplanin or levofloxacin and two contaminated groups that received teicoplanin-soaked or levofloxacin-soaked grafts. The grafts were removed 7 days after implantation and evaluated by quantitative culture.

Results

There was significant bacterial growth inhibition in the groups given systemic or local prophylaxis (P< 0.05). Methicillin-resistantS. epidermidishad greater affinity to Dacron graft when compared with ePTFE graft in the untreated contaminated groups (P< 0.05).

Conclusion

The study demonstrated that the usage of systemic or local prophylaxis and preference of ePTFE graft can be useful in reducing the risk of vascular graft infections caused by staphylococcal strains with high levels of resistance.
Massive lung collapse with partial resolution after several years: a case report
Authors: Govaere Elke , Van Raemdonck Dirk , Devlieger Hugo , Smet Maria-Helena , Verbeken Eric , Proesmans Marijke , De Boeck Kris
Published: October 2005

Background

Bronchitis obliterans is a severe and extremely rare complication of respiratory tract infections in children and is characterized by massive atelectasis and collapse of the affected lung. Of the rare cases reported in the literature all surviving children underwent surgical resection of the collapsed lung.

Case presentation

We report an infant with bronchitis obliterans that was treated conservatively. 5 years after the initial event, partial lung re-expansion was documented.

Conclusion

This case therefore supports a conservative treatment whenever possible with pneumonectomy only as a last treatment option.