bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular modeling of the membrane targeting of phospholipase C pleckstrin homology domains
Authors: Singh Shaneen M. , Murray Diana 
Published: August 2003

AbstractPhospholipases C (PLCs) reversibly associate with membranes to hydrolyze phosphatidylinositol‐4, 5‐bisphosphate (PI[4,5]P2) and comprise four main classes: β, γ, δ, and ε. Most eukaryotic PLCs contain a single, N‐terminal pleckstrin homology (PH) domain, which is thought to play an important role in membrane targeting. The structure of a single PLC PH domain, that from PLCδ1, has been determined; this PH domain binds PI(4,5)P2 with high affinity and stereospecificity and has served as a paradigm for PH domain functionality. However, experimental studies demonstrate that PH domains from different PLC classes exhibit diverse modes of membrane interaction, reflecting the dissimilarity in their amino acid sequences. To elucidate the structural basis for their differential membrane‐binding specificities, we modeled the three‐dimensional structures of all mammalian PLC PH domains by using bioinformatic tools and calculated their biophysical properties by using continuum electrostatic approaches. Our computational analysis accounts for a large body of experimental data, provides predictions for those PH domains with unknown functions, and indicates functional roles for regions other than the canonical lipid‐binding site identified in the PLCδ1‐PH structure. In particular, our calculations predict that (1) members from each of the four PLC classes exhibit strikingly different electrostatic profiles than those ordinarily observed for PH domains in general, (2) nonspecific electrostatic interactions contribute to the membrane localization of PLCδ‐, PLCγ‐, and PLCβ‐PH domains, and (3) phosphorylation regulates the interaction of PLCβ‐PH with its effectors through electrostatic repulsion. Our molecular models for PH domains from all of the PLC classes clearly demonstrate how a common structural fold can serve as a scaffold for a wide range of surface features and biophysical properties that support distinctive functional roles.
Solution structure of the C‐terminal domain from poly(A)‐binding protein in Trypanosoma cruzi: A vegetal PABC domain
Authors: Siddiqui Nadeem , Kozlov Guennadi , D'Orso Iván , Trempe Jean‐François , Gehring Kalle 
Published: August 2003

AbstractPABC is a phylogenetically conserved peptide‐binding domain primarily found within the C terminus of poly(A)‐binding proteins (PABPs). This domain recruits a series of translation factors including poly(A)‐interacting proteins (Paip1 and Paip2) and release factor 3 (RF3/GSPT) to the initiation complex on mRNA. Here, we determine the solution structure of the Trypanosoma cruzi PABC domain (TcPABC), a representative of the vegetal class of PABP proteins. TcPABC is similar to human PABC (hPABC) and consists of five α‐helices, in contrast to the four helices observed in PABC domains from yeast (yPABC) and hyper plastic disk proteins (hHYD). A mobile N‐terminal helix is observed in TcPABC that does not pack against the core of the protein, as found in hPABC. Characteristic to all PABC domains, the last four helices of TcPABC fold into a right‐handed super coil. TcPABC demonstrates high‐affinity binding to PABP interacting motif‐2 (PAM‐2) and reveals a peptide‐binding surface homologous to that of hPABC. Our results demonstrate the last four helices in TcPABC are sufficient for peptide recognition and we predict a similar binding mode in PABC domains. Furthermore, these results point to the presence of putative PAM‐2 site‐containing proteins in trypanosomes.
Intrinsic contributions of polar amino acid residues toward thermal stability of an ABC–ATPase of mesophilic origin
Authors: Sarin Jyoti , Raghava Gajendra P.S. , Chakraborti Pradip K. 
Published: August 2003

AbstractThe nucleotide‐binding subunit of phosphate‐specific transporter (PstB) from mesophilic bacterium, Mycobacterium tuberculosis, is a unique ATP‐binding cassette (ABC) ATPase because of its unusual ability to hydrolyze ATP at high temperature. In an attempt to define the basis of thermostability, we took a theoretical approach and compared amino acid composition of this protein to that of other PstBs from available bacterial genomes. Interestingly, based on the content of polar amino acids, this protein clustered with the thermophiles.
The accuracy of a river bed moulding/casting system and the effectiveness of a low‐cost digital camera for recording river bed fabric
Authors: Chandler Jim H. , Buffin‐Bélanger Tom , Rice Steve , Reid Ian , Graham David J. 
Published: August 2003

AbstractDigital photogrammetry has been used to develop and test an artificial river bed moulding and casting system, which allows the pebbles within a coarse‐grain river bed to be recreated for hydraulic research in a laboratory flow channel or flume. Imagery of both the original streambed and the cast facsimile was acquired using a non‐metric Kodak DCS460 digital camera and digital elevation models and orthophotographs were derived and compared to assess the accuracy of the moulding and casting system. These comparative tests proved to be critical in modifying and developing the system.Additional imagery was obtained in the field using a non‐metric Olympus C3030 ‘‘compact’’ digital camera to assess whether far cheaper camera technology could deliver data appropriate for such comparative examinations. Internal calibration parameter sets and data that were generated were compared with data obtained by the non‐metric Kodak DCS460. These tests demonstrate that digital sensors built around high‐quality 35 mm professional camera bodies and lenses are required for comparative examinations and for similar system development.
Photogrammetry in the Ordnance Survey from Close to MacLeod
Authors: Collier Peter , J. Inkpen Robert 
Published: August 2003

AbstractIn the period after the First World War the Ordnance Survey was relatively slow to recognise the contribution that air survey could make to its work. In part, this was due to external constraints on budgets, which helped to stifle innovation. However, the views of the four Directors General, Close, Jack, Winterbotham and MacLeod, were to play large roles in determining the energy with which innovations were adopted. Both Close and Winterbotham were generally sceptical about the value of air survey, while Jack was well disposed, but constrained by budget limitations. In MacLeod, however, air survey was to find a convinced champion. This paper explores the roles played by the key players and how, in the late 1930s, significant advances were made.
Autonomous space resection using Point‐ and Line‐Based representation of FREE‐FORM control Linear Features
Authors: Habib Ayman , Lin Hsiang Tseng , Morgan Michel 
Published: August 2003

AbstractAutomatic single photo resection (SPR) remains one of the challenging problems in digital photogrammetry. Visibility and uniqueness of distinct control points in the input imagery limit robust automation of the space resection procedure. Recent advances in photogrammetry mandate adopting higher‐level primitives, such as free‐form control linear features, for replacing traditional control points. Linear features can be automatically extracted from the image space. On the other hand, object space control linear features can be obtained from an existing GIS layer containing 3D vector data such as road networks or from newly developed terrestrial mobile mapping systems (MMS). In this paper, two different approaches are presented for simultaneously determining the position and attitude of the imagery as well as the correspondence between image and object space linear features. These approaches are based on two representation schemes of the linear features. The first one represents the linear feature by a sequence of 2D and 3D points along the linear feature in the image and object space, respectively. The second scheme assumes that the feature is modelled by polylines (a sequence of straight‐line segments). Neither approach requires one‐to‐one correspondence between image and object space primitives, which makes the suggested methodology robust against changes and/or discrepancies between the data‐sets involved. This characteristic will be helpful in detecting and dealing with changes between object and image space linear features (due to temporal effects for example). The parameter estimation and matching follow an optimal sequential procedure that is developed and described within this paper, which depends on the sensitivity of the mathematical model relating corresponding primitives at various image regions to incremental changes in the exterior orientation parameters (EOP). Experiments are conducted to compare the algorithms’ efficiency and the accuracy of the estimated EOP using both approaches. Experimental results using real data demonstrate the feasibility and robustness of both representation schemes as well as the methodologies developed. Moreover, different generalisation levels of the polylines representing the free‐form linear features are compared.
Geometric assessment of the kodak DCS Pro back
Authors: Mills Jon P. , Schneider Danilo , Barber David M. , Bryan Paul G. 
Published: August 2003

AbstractThis paper reports on an investigation into the suitability of the Kodak DCS Pro Back for use in close range photogrammetric measurement. The camera back, being used in conjunction with a medium‐format non‐metric camera, has been assessed with a view to using it for low‐ to medium‐order photogrammetric work in architectural recording. Examinations centred upon the stability of the camera back with respect to the camera body and the effects of the removable infrared filter that is present immediately above the camera's focal plane. Ultimately the camera combination was deemed suitable for application in recording of this kind and is now in active use by the Metric Survey Team at English Heritage.
Wage Effects of Drinking in Australia
Authors: Lee Yew Liang 
Published: August 2003

AbstractThis article analyses the wage effects of drinking using the Australian Twin Registry data. A multinomial logit framework is employed to explain the allocation of workers across various drinking states, and to correct for selection bias in the wage equations. It is found that there is a significant positive wage premium for moderate drinking. A favourable family background (during childhood) is positively related to the measure of moderate drinking. Greater genetic endowments are also associated with moderate drinking.
Inflation Expectations, Interest Rates and Arbitrary Income Transfers
Authors: Makin Tony 
Published: August 2003

AbstractUnexpected inflation, disinflation or deflation cause arbitrary income transfers between an economy's borrowers and lenders. This redistribution results from distorted real interest rates that are too high when price level changes are over‐predicted and too low when they are under‐predicted. This article shows that in Australia's case, inflation expectations were mostly biased upwards throughout the 1990s, according to the Melbourne Institute of Applied Economic and Social Research series and to a new derived series based on bond yields, implying that real interest rates were too high over this time. In turn, this caused substantial arbitrary income transfers from debtors to creditors, estimated to have averaged up to 3 per cent of gross domestic product over the period.
Inflation Targeting as a Framework for Monetary Policy: A Cross‐Country Analysis
Authors: Seyfried William , Bremmer Dale 
Published: August 2003

AbstractThis study makes use of a dynamic Taylor‐type model to examine the conduct of monetary policy by central banks that profess to engage in inflation targeting. Previous research regarding inflation targeting and Taylor‐type rules is reviewed and a dynamic Taylor‐type model is developed. Tests for regime shifts upon the adoption of inflation targeting indicate a significant change in policy in each of the nations in the study for which sufficient data were available. Next, the central bank reaction functions were estimated. Results suggest that most of the central banks conducted a policy of inflation targeting by seeking to contain inflationary pressures rather than reacting to current inflation.
On the Market Failure in a Dixit‐Stiglitz Setup with Two Trading Cities
Authors: Hadar Yossi , Pines David 
Published: August 2003

AbstractThis study discusses the reasons for market failure and its bias in an economy with two cities and two final goods: tradeable differentiated products and non‐tradeable housing. It is shown that inside the city, as in Dixit and Stiglitz (1977), diversity (number of firms) is too small. With regard to the population partition between the cities, the paper distinguishes between a marginal and a global market bias against agglomeration or dispersion (in a second‐best context). The reasons for a marginal bias are twofold: a gap between marginal and average labor productivity and the (excessive) labor employed in housing production which vary between the large and the small cities. The source of the global bias is multiple stable equilibria. The marginal bias may be in an opposite direction to the global bias, such that more agglomeration may be marginally desirable, whereas full dispersion is (second‐best) optimal. Simulations demonstrate that the same market structure and potential source of market failure may imply bias in different directions, depending on the aggregate population size.
The Political Power of the Retirees in a Two‐Dimensional Voting Model
Authors: Casamatta Georges 
Published: August 2003

AbstractWe show that the retirees are able to obtain favorable pension policies whereas they belong to a minority in the population. The argument relies on the multidimensional nature of the political process. We consider a two‐dimensional collective choice problem. The first of these choices is the level of the contribution rate to the Pay‐As‐You‐Go pension system. The second is a noneconomic decision, unrelated to the pension system. Using a political agency model, we show that, as soon as the retirees are sufficiently numerous, the equilibrium tax rate may be higher than the tax rate preferred by the young, who yet constitute a majority over the pension issue.
Social Security Wealth and Retirement Decisions in Italy
Authors: Brugiavini Agar , Peracchi Franco 
Published: August 2003

Abstract.  This paper uses administrative data to study the retirement decisions of Italian private‐sector non‐agricultural employees during the period 1977–97. Our analysis tries to assess the importance of the financial incentives built into the social security system. The basic idea is very simple: at any given age, and based on the available information, workers compare the expected present value of two alternatives: retiring today or working one more year, and then choose the best one.A key role in this kind of comparisons is played by social security wealth, whose level and changes reflect the expectations about the profile of future earnings and the institutional features of the social security system. The various incentive measures that we consider differ in the precise weight given to the social security wealth that workers accrue as they continue to work.Our model does not provide a structural representation of the retirement process. A worker's decision is modeled here following a ‘quasi reduced‐form’ approach, with the incentive measures entering as predictors of the worker's choice in addition to standard variables. The estimated models are then used to predict retirement probabilities under alternative policies that change social security wealth and derived incentive measures.
Early Retirement in Italy: Recent Trends
Authors: Inglese Luca 
Published: August 2003

Abstract.  The analysis presented provides new statistical information on pensioners receiving seniority retirement benefits and highlights the positive effects of specific factors on their pension income.The statistical estimates suggest that work incentives are weak and steady job exits before the normal retirement age continue, especially for civil servants.In particular, since seniority benefits are based on a long contribution history, their corresponding level of pension income is high. This is not true for pensioners receiving old age benefits because of their incomplete work history.
Short‐term harvest planning including scheduling of harvest crews
Authors: Karlsson J. , Rönnqvist M. , Bergström J. 
Published: August 2003

AbstractThe problem we consider is short‐term harvesting planning for a total planning period of 4–6 weeks where we want to decide the harvest sequences or schedules for harvest crews. A schedule is an order or sequence of harvest areas assigned to each crew. The harvesting of areas is planned in order to meet industrial demand. The total cost includes harvesting, transportation, and storage. One considerable cost is due to the quality reduction of logs stored at harvest areas. There are a number of restrictions to be considered. Areas are of varying size and the composition of assortments in each area is different. Each harvest team has different skills, a different home base, and different production capacity. Another aspect is the road network. There is a cost related to road opening (restoring, snow removal). In this paper, we develop a mixed integer programming (MIP) model for the problem. The schedules are represented by 0/1 variables. With a limited number of schedules, the problem can be solved by a commercial MIP solver. We have also developed a heuristic solution approach that provides high‐quality integer solutions within a distinct time limit to be used when more schedules are used. Computational results from a major Swedish forest company are presented.
A solution approach for log truck scheduling based on composite pricing and branch and bound
Authors: Palmgren Myrna , Rönnqvist Mikael , Värbrand Peter 
Published: August 2003

AbstractThe logging truck scheduling problem is one of the most complex routing problems where both pick‐up and delivery operations are included. It consists in finding one feasible route for each vehicle in order to satisfy the demands of the customers and in such a way that the total transport cost is minimized. We use a mathematical formulation of the log truck scheduling problem where each column represents a feasible route. We generate a large pool of columns based on solving a transportation problem. Then we apply a composite pricing algorithm, which mainly consists of pricing the pool of columns and maintain an active set of these, for solving the LP relaxed model. A branch and price approach is used to obtain integer solutions in which we apply composite pricing to generate new columns. Numerical results from case studies at Swedish forestry companies are presented.
A role for stakeholder objectives in USDA Forest Service plan revisions: A case study on the White River National Forest
Authors: Kent B. , Kaval P. , Berry J. , Retzlaff M. , Hormaechea D. , Shields D. 
Published: August 2003

AbstractIn August 1999, The White River National Forest, headquartered in Glenwood Springs, Colorado, USA, released a draft revised forest plan, engendering almost immediate and widespread controversy. This paper describes steps taken prior to release of the final plan to reduce the controversy by linking stakeholder objectives to plan alternatives. Information from three surveys and public comments was analyzed to characterize stakeholder objectives. A series of public meetings was conducted to validate the objectives and provide information needed to develop an objectives hierarchy, which was used to characterize means objectives that were linked to alternative plans, using associated attributes. A key finding was that stakeholders align their objectives for forest management with one of two schools of thought; one having an ecosystem conservation orientation and the other, a human use/economic sustainability orientation. The final plan, released in June 2002 received a greater level of positive reaction in the media and elsewhere.
Predicting Job Performance with a Fuzzy Rule-Based System
Authors: Craiger J. Philip , Coovert Michael D. , Teachout Mark S. 
Published: August 2003

Classification problems affect all organizations. Important decisions affecting an organization's effectiveness include predicting the success of job applicants and the matching and assignment of individuals from a pool of applicants to available positions. In these situations, linear mathematical models are employed to optimize the allocation of an organization's human resources.Use of linear techniques may be problematic, however, when relationships between predictor and criterion are nonlinear. As an alternative, we developed a fuzzy associative memory (FAM: a rule-based system based on fuzzy sets and logic) and used it to derive predictive (classification) equations composed of measures of job experience and job performance. The data consisted of two job experience factors used to predict measures of job performance for four US Air Force job families. The results indicated a nonlinear relationship between experience and performance for three of the four data sets. The overall classification accuracy was similar for the two systems, although the FAM provided better classification for two of the jobs. We discuss the apparent nonlinear relationships between experience and performance, and the advantages and implications of using these systems to develop and describe behavioral models.
Sandwich Construction with Carbon Foam Core Materials
Authors: Sihn Sangwook , Rice Brian P. 
Published: August 2003

To study suitability of the emerging ultralightweight carbon foams in load-carrying structures, the state-of-the-art carbon foams from various manufacturers were evaluated as core material in a sandwich construction. The carbon foams were firstly characterized by measuring compressive and shear mechanical properties. The carbon foam possessed highly anisotropic properties between in-plane and through-the-thickness directions. The foams aged at 316°C (600°F) for 100 h in air lost 0.6% of their weight and showed little degradation in the properties within the scatter range of test data. The carbon foams tested at an elevated temperature of 316°C (600°F) showed no degradation in the compressive modulus and strength as compared to the properties measured at a room temperature of 21°C (70°F). Sandwich beams with laminated composite facesheets were fabricated with a carbon foam core and tested under static and fatigue four-point bending loads. The beams under the static loadings showed nearly linear elastic behavior until the maximum failure loads, and then postfailed either in yielding or in brittle mode following the postfailure behavior of the carbon foam core. The failure occurred in the core material in a shear mode. Sandwich beams with carbon foam cores survived after a few hundred or even a few hundred thousands of cyclic loads. Both the moduli and strength of the beams remained nearly unchanged after the fatigue loads. Central displacement and strain measurements at the gauge locations matched well with the analytical solution from a sandwich-beam theory. The shear moduli and strength of the carbon foams calculated from the four-point bending tests were in good agreement with those from torsional tests. The sandwich beam test technique is useful for the determination of the foam shear properties, especially for uncoupled shear properties of only one plane. The sandwich beams with the carbon foam cores tiled together in the middle of the beam exhibited nearly identical load-displacement behavior as well as the shear failure mode to those of the beam made with an intact core. From the modulus point of view, the hole-drilling with the high-density foams is a better way of achieving the weight reduction in the sandwich construction than using the low-density foams. If the materials were removed in the noncritically loaded area (e.g., central section of the beams under the four-point bending), the weight reduction can be achieved without sacrificing much strength property of the core materials as well.