bluuebunny/crossref_metadata_2025 huggingface dataset:
Supply Decisions among Dentists Working within a Fixed‐fee System of Dental Care Provision
Authors: Grytten Jostein , Hoist Dorthe , Grytten Linda
Published: April 2007

In Norway fees for dental treatment did not increase at the same rate as prices for other goods and services during the 1980s. The aim of this study was to examine how this decrease in fees in real terms has influenced dentists' work decisions with respect to supply of services. Data on characteristics of the dentist and the dental practice were collected for 1979, 1984, and 1986. The dependent variable was supply of dental services, measured as the number of patient care hours worked per annum. The hourly fee for dental care was equivalent to dentists' hourly wage rate. Supply increased as fees decreased. This could be explained either as a response of the patient or the dentist to reduced fees. Although the data did not give conclusive evidence as to which effect was most important, the authors have put forward the view that the main effect was dentists' response to reduced fees. The main argument put in favor of this view is that dentists have an overall knowledge of the effect of a change in fees on their income. The impact of a change in fees is much greater on the provider who supplies the services to many individuals over a long period of time, than on an individual consumer who buys the services once or twice a year. It was concluded that, in the short run, a fixed‐fee schedule may not be very effective in limiting costs for dental care.
Improving Dental Epidemiologic Data Collection with Computers
Authors: Joshi Anil , McDermott Susan , Marcus Philip , Douglass Chester W. , Jette Alan
Published: April 2007

A computerized dental data recording system (DDRS) was developed for the New England Elder Dental Study to improve data quality and increase field staff efficiency. The DDRS displays video screens similar to traditional paper forms to record data on corona) and root caries, dentate and denture status, subacute bacterial endocarditis screening, gingival bleeding, calculus, and periodontal attachment level. DDRS provides facilities for date and exam‐component time tracking, on‐tine contextual comments, random record retrieval, editing, data backup, and data output in various data formats. This study compared the DDRS with a paper‐form system for data entry accuracy. Dental caries and periodontal disease measurement data from 38 subjects were recorded on paper forms and independently entered using DDRS. The DDRS identified 150 illogical data errors, 39 inconsistent data errors, 7 invalid data and 34 miscellaneous data errors. Four technicians with field experience using both paper forms and DDRS reported time savings using DDRS in the field. DDRS has the potential for additional time savings by minimizing the time for data coding, cleaning, and management. Results demonstrate that DDRS could improve the quality of oral epidemiologic data by mandating strict adherence to protocols, preventing errors, and increasing field efficiency.
Utilization in Alberta's Universal Dental Plan for the Elderly, 1974‐91
Authors: Lewis Donald W. , Thompson G. W.
Published: April 2007

Since 1973 the government of Alberta, a Canadian province of 2.4 million people, has funded a dental care plan for all residents over 64 years old and their dependents. It is the only dental plan in North America that covers all seniors and their dependents residing in a state or province. Under this plan, just over 270,000 persons (in 1990–91) are eligible for comprehensive, premium‐free dental services provided by dentists and denturists in private practice on a fee‐for‐service basis. The plan's design, administration, utilization, and costs are reviewed. Utilization increased from 27 percent of eligibles using the plan in 1974–75 to 44 percent in 1990–91, and the mean number of services per user rose from 4.9 to 6.9 during the same time period. Although the cost per eligible person has increased about 200 percent, from Canadian (C) $42 to C $131, these costs only began to exceed the rate of inflation in 1986–87. Even though just 12 percent of the two main providers participating in the plan are denturists, nearly 22 percent of plan patients attended denturists rather than dentists for their complete dentures. Fees paid to dentists by the plan have decreased over time relative to the standard fees for the various services listed annually in the Alberta Dental Association fee guide. The apparent growth of direct additional billing by dentists of plan users to recover the difference between their usual fees and those paid by the plan and the effects of greater plan utilization are discussed, as are future potential difficulties in the plan's administration.
Eligible Veterans' Choice Between VA‐covered and Non‐VA‐covered Dental Care
Authors: Gilbert Gregg H. , Branch Laurence G. , Longmate Jeffrey
Published: April 2007

Veterans who were eligible for dental care in Department of Veterans Affairs (VA) facilities at no monetary cost responded to a mailed questionnaire. Seventy‐one percent were aware that they were actually eligible for VA dental care. However, only 48 percent reported the VA as their only or primary source of dental care. Eligibility status, perceived quality of VA dental care, use of VA medical care, perception that one's income meets expenses, and perceived need for dental care were significant correlates of using the VA as one's current source of dental care. Level of formal education, perception that one's income meets expenses, transportation pattern, geographic distance from a VA facility, and eligibility status were significant correlates of using the VA as one's current medical care source. Research on VA utilization offers the opportunity to study issues of access to, and use of, a large public health care system whose patients largely receive care at no monetary cost. Veterans' use of VA dental and medical care is apparently influenced by a wide variety of factors, ranging from barriers to access to non‐VA systems, to characteristics of the VA delivery system itself, to need for treatment.
Fluoride Concentrations in Human and Rat Bone
Authors: Eble Dennis M. , Deaton Thomas G. , Wilson Frank C. , Bawden James W.
Published: April 2007

The most recent report on fluoride concentrations ([f]) in human bone was published over a decade ago. Such data are of interest in the context of changing patterns in systemic fluoride exposure. In the study reported here, bone samples were collected from 24 human subjects who underwent orthopedic surgery. Medical histories and the best possible life‐time systemic fluoride exposure information were obtained from each subject. Bone samples were assayed for fluoride concentration using the acid diffusion, ion selective electrode method. For ash from whole bone, the lowest value was 378 ppm in a 16‐year‐old subject, and the highest value was 3,708 ppm in a 79‐year‐old person. Fluoride concentrations in bone were significantly correlated with age (r=.62). The regression line intercept at birth was 442 ppm, and the slope was 22 ppm per year. When measured separately, trabecular bone ash fluoride concentrations were significantly higher than the corresponding cortical bone values. Trabecular and cortical bone samples from rats' drinking water containing 75 ppm F were assayed for F. The mean trabecular bone fluoride concentration was significantly higher than the mean cortical bone concentration. There was close agreement between F assay results using a modification of the acid diffusion method and the method originally reported by Singer and Armstrong. The human bone ash [F] values reported in this study are similar to those reported from other North American subjects over the last three decades. These findings are of interest in the context of evidence indicating increased systemic fluoride exposure in the United States population. They may also be considered in efforts to evaluate the relevance of the National Institute of Environmental Health Sciences fluoride carcinogenesis study.
Mercury in Dental Amalgam‐a Public Health Concern?
Authors: Flanders Raymond A.
Published: April 2007

Dental amalgam has been the subject of intermittent controversy since it was introduced into dental practice approximately 150 years ago. The controversy has centered on the use of mercury in dental amalgam and the potential health implications to dental patients and dental health professionals from mercury exposure. In recent years the debate over the use of dental amalgam has intensified due to several articles in professional journals and media coverage by television and the press. This paper reviews the recent literature regarding dental amalgam, describes the activities of the antiamalgamists, examines the alternatives to dental amalgam, and reviews the recommendations for additional research. The existing scientific evidence does not demonstrate that mercury in dental amalgam poses a public health hazard. However, researchers on both sides of the controversy agree that much remains to be examined about the health implications of dental amalgam and that the subject merits continued research.
FDA Regulation of OTC Oral Health Care Drug Products
Authors: Rippere Jeanne L.
Published: April 2007

The history of the involvement of the Food and Drug Administration in the regulation of over‐the‐counter (OTC) drugs is reviewed. The development of monographs containing standards for drugs, the function of the advisory panels, and the classification of dental drug products are explained. Examples of ingredients in each category are given. The current opinion of the FDA concerning antiplaque and antigingivitis claims is also discussed.
FDA Regulation of Dental Devices: Past, Present, and Future
Authors: Tylenda Carolyn A.
Published: April 2007

The organization of the Food and Drug Administration as related to dental devices is described. The classification according to safety and efficacy of devices is described and examples are given. The process of submitting a Premarket Notification [(510(k)] for class I and II devices, a Premarket Approval (PMA) for class III devices and an Investigational Device Exemption (IDE) are described. The clinician is told how to report problems with medical devices.
Interactions as Seen by an Industry Representative among the FDA, the ADA, and Industry in Preparing a Restorative Material for Market
Authors: Dougherty Emery W.
Published: April 2007

The regulation of a restorative material in the international and the American markets is discussed. The 510(k) process of approval by the Food and Drug Administration allows marketing of safe, effective, and improved materials in the shortest time at the lowest cost. The American Dental Association contributes to developing consensus performance standards in the United States. Acceptance of International Standards Organization standards is discussed.
Factors influencing the effectiveness of research ethics committees
Authors: Schuppli C A , Fraser D
Published: April 2007

Research ethics committees—animal ethics committees (AECs) for animal-based research and institutional research boards (IRBs) for human subjects—have a key role in research governance, but there has been little study of the factors influencing their effectiveness. The objectives of this study were to examine how the effectiveness of a research ethics committee is influenced by committee composition and dynamics, recruitment of members, workload, participation level and member turnover. As a model, 28 members of AECs at four universities in western Canada were interviewed. Committees were selected to represent variation in the number and type of protocols reviewed, and participants were selected to include different types of committee members. We found that a bias towards institutional or scientific interests may result from (1) a preponderance of institutional and scientist members, (2) an intimidating atmosphere for community members and other minority members, (3) recruitment of community members who are affiliated with the institution and (4) members joining for reasons other than to fulfil the committee mandate. Thoroughness of protocol review may be influenced by heavy workloads, type of review process and lack of full committee participation. These results, together with results from the literature on research ethics committees, suggested potential ways to improve the effectiveness of research ethics committees.
Legal and ethical considerations in processing patient-identifiable data without patient consent: lessons learnt from developing a disease register
Authors: Haynes Charlotte L , Cook Gary A , Jones Michael A
Published: April 2007

The legal requirements and justifications for collecting patient-identifiable data without patient consent were examined. The impetus for this arose from legal and ethical issues raised during the development of a population-based disease register. Numerous commentaries and case studies have been discussing the impact of the Data Protection Act 1998 (DPA1998) and Caldicott principles of good practice on the uses of personal data. But uncertainty still remains about the legal requirements for processing patient-identifiable data without patient consent for research purposes. This is largely owing to ignorance, or misunderstandings of the implications of the common law duty of confidentiality and section 60 of the Health and Social Care Act 2001. The common law duty of confidentiality states that patient-identifiable data should not be provided to third parties, regardless of compliance with the DPA1998. It is an obligation derived from case law, and is open to interpretation. Compliance with section 60 ensures that collection of patient-identifiable data without patient consent is lawful despite the duty of confidentiality. Fears regarding the duty of confidentiality have resulted in a common misconception that section 60 must be complied with. Although this is not the case, section 60 support does provide the most secure basis in law for collecting such data. Using our own experience in developing a disease register as a backdrop, this article will clarify the procedures, risks and potential costs of applying for section 60 support.
An allozyme study of sexual and vegetative regeneration in Hieracium pilosella
Authors: Bruun Hans Henrik , Scheepens J.F. , Tyler Torbjörn
Published: April 2007

Allozyme markers were used to fingerprint clones of the grassland plant Hieracium pilosella L. and, by inference, to estimate the relative importance of sexual and vegetative reproduction in a population. Field studies in populations of clonal plant species have often reported negligible or absent recruitment from seed. In contrast, studies of genetic markers have found substantial clonal diversity in populations, suggesting recruitment of new genets into established populations. Our results showed that H. pilosella regenerates from seed both within and between dense clonal patches. Two sites differing in environmental conditions were sampled to investigate how the balance between seed-derived and stolon-derived recruitment changes with biotic and abiotic stress. In a relatively drought-prone site on a south-facing slope, the balance was shifted towards recruitment from seed, compared with a mesic site in which vegetative regeneration was more important.
The morphology of the terminal phalanges in Permo-Carboniferous synapsids: an evolutionary perspective
Authors: Maddin Hillary C , Reisz Robert R
Published: April 2007

Morphological features of the terminal phalanges of extinct tetrapods can be used to infer whether or not keratinous claws were present even though these structures are not preserved in the fossil record. Such features as dense vascularization grooves and foramina, and a general claw-like morphology, are present in some of the earliest fully terrestrial tetrapods, the Permo-Carboniferous synapsids. Early synapsids are represented by a rich fossil record that preserves the detailed anatomy of the terminal phalanges and allows for an examination of the early evolution of these structures in a well-resolved phylogenetic context. The pattern of change in the morphology of the terminal phalanges of five basal synapsids, Cotylorhynchus romeri, Varanops sp., Edaphosaurus boanerges, Haptodus garnettensis, and Dimetrodon limbatus, reveals a clear trend from a broad, flat, and spatulate morphology in the basal taxa to a tall, narrow, and curved structure. This trend in overall shape change does not reflect changes in feeding behaviour. The size and shape of the flexor tubercle appears to be a factor of size and function, rather than possessing a phylogenetically informative signal. The osteological features used to infer the presence of a keratinous sheath in the synapsids are also observed in the non-amniote taxon Diadectes absitus. This indicates that claws were not an amniote innovation and that they instead originated somewhere outside the crown group Amniota.
Thermobarometry and geochronology of the Uvauk complex, a polymetamorphic Neoarchean and Paleoproterozoic segment of the Snowbird tectonic zone, Nunavut, Canada
Authors: Mills A J , Berman R G , Davis W J , Tella S , Carr S , Roddick C , Hanmer S
Published: April 2007

The Uvauk complex is an ultramylonite-bounded, granulite-facies suite of anorthosite–gabbro that forms part of the Chesterfield Inlet segment of the Snowbird tectonic zone. Following initial anorthosite–gabbro magmatism at ca. 2.71 Ga and a cryptic 2.62–2.60 Ga event marked by zircon and monazite growth, the Uvauk complex experienced two high-grade tectonometamorphic events at 2.56–2.50 and 1.91–1.90 Ga. Similar to the 2.56–2.50 Ga development of other shear zones in the region, the upper-amphibolite-facies to granulite-facies, moderately high-pressure (8.4–11.0 kbar and 705–760 °C) (1 kbar = 100 MPA) M1 event is interpreted to have involved the structural emplacement of ca. 2.71 Ga Uvauk complex rocks on ca. 2.68 Ga tonalitic rocks to the south. Granulite-facies, high-pressure (11.2–14.7 kbar and 695–865 °C) M2 metamorphism, gabbroic magmatism, and mylonite development within the complex at ca. 1.9 Ga culminated with ~3.5 kbar decompression at high temperature. Clockwise pressure–temperature–time (P–T–t) paths reflect crustal thickening, thought to be related to the early accretionary history of the Trans-Hudson Orogen. A thermal overprint at ca. 1.85–1.75 Ga resulted in retrograde metamorphism (5.8–6.0 kbar and 625–695 °C) associated with post-tectonic granitoid plutonism.
Possible refugia in the Alexander Archipelago of southeastern Alaska during the late Wisconsin glaciation
Authors: Carrara P E , Ager T A , Baichtal J F
Published: April 2007

The interpretation of the extent of late Wisconsin glaciation in southeastern Alaska has varied between geologists and biologists. Maps and reports of the region prepared by geologists commonly indicated that late Wisconsin ice extended as a large uniform front west to the edge of the continental shelf. However, the distribution of plants and animals in the region has led many biologists to suggest that there may have been ice-free areas that served as refugia during the late Wisconsin. Based on analyses of aerial photographs, topographic maps, and bathymetric charts, in conjunction with a review of previous literature and reconnaissance fieldwork throughout the region, this study presents data supporting a limited ice extent in the Alexander Archipelago during the late Wisconsin and identifies possible ice-free areas that may have served as refugia. These areas include (1) the Fairweather Ground, (2) the Herbert Graves Island area, (3) the western coast of southern Baranof Island and adjacent continental shelf, (4) Coronation Island and the adjacent continental shelf, (5) the Warren Island area, (6) the continental shelf from west of Heceta Island to Forrester Island in the south, (7) parts of the west coast of southern Dall Island, and (8) lowland areas in southern Prince of Wales Island. The identification of these possible refugia has bearing on the recolonization of the Alexander Archipelago, as they could have served as centers of biotic dispersal upon regional deglaciation and as stepping stones for early humans with a maritime tradition entering the western hemisphere from Asia.
Recent climate and stable isotopes in modern surface waters of northernmost Ungava Peninsula, Canada
Authors: Saulnier-Talbot Émilie , Leng Melanie J , Pienitz Reinhard
Published: April 2007

The isotope composition (δ18O and δD) of surface waters was measured over a 26-month period near three localities situated along the northern coast of Ungava Peninsula, Quebec, Canada. To characterize the present-day local hydrological settings, the oxygen and hydrogen isotope ratios were measured from precipitation and were compared to local and regional climate data. We show that the modern surface waters contain information on climate and that this relationship is likely to be transferred to biotic components within the lakes. These components, once sedimented, are therefore likely to form an archive of climate change. The new data presented here show the possibility of isotope paleoclimatic investigation based on lake sediments in the northern coastal region of Ungava Peninsula.
Workforce training initiatives for megaproject success
Authors: Fayek Aminah Robinson , Yorke Mike , Cherlet Ron
Published: April 2007

The recent trend of mega construction projects has resulted in some major challenges and opportunities for construction management and execution. One of these challenges is in construction workforce renewal and training. With a rapidly aging workforce, the challenge is to attract new workers while simultaneously providing adequate training for the influx of young and sometimes inexperienced people. Client–owners are now recognizing the economic need to implement advanced training on their projects, to improve productivity and minimize losses. With workforces ranging in the thousands, skilled labour has one of the most significant impacts on project outcomes. Alberta has seen a significant increase in workforce training initiatives, particularly since 2000. The objectives of this paper are to provide an overview of the recent advances and initiatives in workforce training in Alberta within the unionized building trades sector of the industrial construction industry and to highlight the economic significance of these initiatives for mega construction projects. The training contributions made by other key organizations are also presented. Key words: Alberta, apprentices, industrial construction, labour force, mentoring, trades, training, workforce.
Project innovation - a function of procurement mode?
Authors: Russell A D , Tawiah P , Zoysa S De
Published: April 2007

The use of public-private partnerships (P3s) has increased in popularity with governments worldwide as a way of meeting ever-increasing demands for infrastructure, such as highways, water supply and wastewater treatment facilities, hospitals, and schools. One of several arguments forwarded by P3 advocates in support of one or more P3 variants as a procurement mode (in place of traditional design–bid–build (DBB) procurement for delivering such infrastructure) is the ability of a P3 to harness more of the innovative capability of the private sector. It is asserted that this capability results in lower capital or life-cycle costs, shorter delivery time, and enhanced long-term project performance. In this paper, we examine the notion that the innovation potential of the private sector is a function of delivery mode, and we describe findings from a study to identify evidence to support or contradict such a viewpoint. We have identified 22 factors or conditions that can act as drivers or inhibitors of innovation for infrastructure projects as a function of procurement mode and project context (e.g., project type, project scale, nature of competition, risk assignment). The product, process, organizational–contractual, and financial–revenue innovations achieved on a major transportation project are then reviewed, and innovation drivers that were present are discussed. The factors and conditions influencing the choice of procurement mode for a large-scale student housing facility are also discussed.Key words: infrastructure procurement, public–private partnerships, innovation drivers and inhibitors, case studies.
Assessment of precast stringer highway bridges using mean load method
Authors: Panesar Daman K , Bartlett F Michael
Published: April 2007

The mean load method of the Canadian Highway Bridge Design Code is used to evaluate the shear and bending moment reliability of existing precast "type G" stringer bridges in Alberta that date from the late 1950s. The overall stringer population is categorized into distinct subpopulations using bridge-specific factors, including the degree of deterioration and approach span condition, which are readily identified during a brief field visit or from inspection reports. Critical sections to be investigated for reliability resisting shear forces or bending moments are determined. The reliability indices decrease if the reinforcement is corroded or the bridge approach is not smooth, and the reduction of the maximum axle loads permitted by legislation due to these factors is quantified. For bridge subpopulations where the actual reliability index is less than the target value for current legal axle loads, the critical axle load for moment is less than that for shear. Therefore, if flexural distress is not noted during inspection of such structures, they are likely adequate for the actual loading they are subjected to.Key words: corrosion, deterioration, dynamic load allowance, mean load method, reliability, visual inspection.
Load and resistance data for precast stringer highway bridges
Authors: Panesar Daman K , Bartlett F Michael
Published: April 2007

Statistical parameters for the load effects and resistances of precast "type G" stringer bridges erected in Alberta since the late 1950s are presented to assist practicing engineers assessing similar bridges using the mean load method. The load effect data include unit weight data for normal weight and two lightweight concretes; traffic volumes, gross vehicle weights, and single, tandem, and tridem axle weights observed on primary, secondary, and local roads; and dynamic load allowances for shear and bending moment on short span bridges. Extreme annual traffic loads are derived. The resistance data include compressive and tensile strengths of normal weight and two lightweight concretes and yield strengths for corroded and uncorroded reinforcing steel. Additional statistical parameters are presented to account for other readily discerned bridge-specific idealization factors that affect the reliability indices. Professional factors for flexural and shear resistance are derived using experimental data reported from past investigations of type G stringers by others.Key words: concrete, core tests, corrosion, dynamic load allowance, material properties, single axles, tandem axles, tridem axles, reliability.
Data warehousing for construction equipment management
Authors: Fan Hongqin , Kim Hyoungkwan , Zaïane Osmar R
Published: April 2007

Equipment logistics, maintenance, and repair are important aspects of construction equipment management. A well-managed equipment fleet helps reduce downtime, as well as total maintenance and repair costs. With quickly growing fleets of equipment, large contractors tend to divert the maintenance and repair of equipment from equipment managers to project managers. As a result, the equipment managers shift their attention from operational-level decision-making to corporate-level strategic decision-making regarding equipment management, which is often a challenging job with the current equipment management system. This paper presents an equipment data warehouse and a prototype decision support system (DSS). The proposed equipment data warehouse enables equipment managers to visually analyze the equipment fleet data from different perspectives and at various level of details. The data-warehouse-based DSS facilitates high-level, fact-based decision-making regarding equipment logistics, supplies, maintenance, repair, and replacement and has higher levels of performance and flexibility than the current equipment management system.Key words: data warehouse, decision support system, equipment management, multidimensional modeling.
Installation procedure for thermal conductivity matric suction sensors and analysis of their long-term readings
Authors: Tan Elsa , Fredlund Delwyn G , Marjerison Brent
Published: April 2007

Thermal conductivity matric suction sensors have enabled continuous and long-term measurement of matric suction and temperature, even in remote locations. Long-term temperature and matric suction readings were obtained from below two thin-membrane-system sites in Torquay and Bethune, Saskatchewan. The method used to install the sensors and the data acquisition system is presented. An understanding of the subgrade soil suction and temperature changes throughout the year was obtained from the data. The change in matric suction and temperature with depth and distance was also determined. Observation of the amplitude and frequency of the fluctuations in the temperature readings provided a better understanding of the changing trends. Environmental effects, such as hysteresis associated with drying and wetting of the sensors and the effect of the ambient temperature on the sensors, were found to influence the matric suction readings. Several correction factors have been proposed to eliminate the influence of the ambient temperature, and the correction methods are compared.Key words: thermal conductivity, matric suction, sensors.
Effect of sample torsional stiffness on resonant column test results
Authors: Kumar Jyant , Clayton C RI
Published: April 2007

A number of resonant column tests were conducted in torsion on aluminium cylindrical bars. By changing the length to diameter ratio of these specimens, the resonant frequency was varied between 52 and 332 Hz. The values of the shear wave velocity (VS) and damping ratio (D) determined from these tests were found to remain acceptable up to a resonant frequency of about 175 Hz. Thereafter, with an increase in the torsional stiffness of the specimen, there was a significant decrease in VSof up to 32.2%, corresponding to a resonant frequency of 332 Hz, and a considerable increase in the damping was noticed. An apparent increase in the mass polar moment of inertia of the driving mechanism was also observed at a greater resonant frequency. The study reveals that, even for a stiff specimen, it is possible using the resonant column tests to accurately determine the dynamic properties of the specimen, provided that the length to diameter ratio of the specimen is increased so that the resonant frequency remains smaller than 175 Hz.Key words: damping, dynamic testing, resonant column test, resonant frequency, shear modulus.
Relationship between soil structure and mechanical behavior for an expansive unsaturated clay
Authors: Miao Linchang , Houston Sandra L , Cui Ying , Yuan Junping
Published: April 2007

To investigate the soil structure and mechanical behavior of an unsaturated expansive clay soil, triaxial and mercury intrusion tests have been performed and are presented in this paper. Also an optical test system was developed for studying the internal structure evolution of the unsaturated expansive soil during shear-loading tests. The research results show a linear relationship between the cohesion intercept and the degree of saturation of the unsaturated clay for the test data. For the tested soil, the pore-size distribution curves were found to be bimodal. The measurement results from mercury intrusion tests confirm that the micropores of Guangxi expansive soils of this study remain constant, and that the macropores vary with the dry density of soil samples. Comparing the volumetric strain curves with the soil particle area curves, some correlation and dependence on the macropore variation of soil samples during shear-loading tests can be shown to exist.Key words: soil structure, mechanical behavior, unsaturated soil, mercury intrusion, expansive clay.
Analytical solutions and design curves for vacuum-assisted consolidation with both vertical and horizontal drainage
Authors: Rujikiatkamjorn Cholachat , Indraratna Buddhima
Published: April 2007

A system of vertical drains combined with vacuum preloading is an effective method for promoting radial flow to accelerate soil consolidation. This study presents the analytical modeling of the consolidation of vertical drains incorporating vacuum preloading considering both vertical and horizontal drainage. The effects of a number of dimensionless parameters involving the drain length, soil permeability, and vacuum pressure are examined through average excess pore pressure, degree of consolidation, associated settlement, and time factor analyses. An analysis of selected case histories compliments the use of the proposed solutions. Design charts are also presented for practical use.Key words: analytical solution, consolidation, design charts, vertical drains.
Dewatering of mine tailings using electrokinetic geosynthetics
Authors: Fourie A B , Johns D G , Jones CJ FP
Published: April 2007

Many mining operations produce tailings that dewater very slowly under self-weight consolidation. One way of reducing the water content of such tailings is by electroosmotic dewatering. Although the technique has been used with some success in civil engineering applications, it is still largely seen as a solution of last resort. This is probably due to the high energy costs reported in the literature, as well as problems of very rapid corrosion of metal electrodes. This paper describes a study using newly developed electrokinetic geosynthetics (EKGs) as electrodes for the in situ dewatering of mine tailings. Laboratory tests were undertaken on mineral sands tailings in both a purpose-built testing cell and a laboratory testing tank using EKGs, followed by an outdoor experiment in a tank containing approximately 9 m3of the tailings. This test was run for over 2 months. Energy consumption in the outdoor test was less than 1 kWh per dry tonne of material dewatered and there was no sign of electrode deterioration even after 2 months of usage. The results point to a potentially powerful technique for reducing the water content of tailings ponds in situ, thus increasing storage space, improving stability, and facilitating closure of these facilities.Key words: tailings, dewatering, electroosmosis, electrokinetic geotextiles, consolidation.
Monte Carlo simulation study of the effects of acidity and LET on the primary free-radical and molecular yields of water radiolysis — Application to the Fricke dosimeter
Authors: Autsavapromporn Narongchai , Meesungnoen Jintana , Plante Ianik , Jay-Gerin Jean-Paul
Published: April 2007

Monte Carlo simulations are used to investigate the effects of acidity (pH) on the primary yields of various chemical species produced in the radiolysis of de-aerated aqueous sulfuric acid solutions over the range from neutral solution to 0.4 mol/L H2SO4. The effects of the quality of radiation, measured in terms of linear energy transfer (LET), have also been studied for LET varying from ~0.3 to 15 keV/µm at ambient temperature. Our results show that an increase in acidity (1 < pH < 4) leads to an increase in the yield [Formula: see text] of the "reducing" free radicals (hydrated electron and H atom) and a slight increase in G·OH and [Formula: see text], while there is a slight decrease in [Formula: see text] At pH < 1, OH radicals react with HSO4- anions to form SO4·– radicals, resulting in a steep decrease in G.OH. By contrast, in the range of pH from ~4 to 7, the calculated yield values are independent of sulfuric acid concentration. In both neutral water and 0.4 mol/L H2SO4 (pH 0.46) solutions, the primary molecular yields increase upon increasing LET to ~15 keV/µm with a concomitant decrease in those of free radicals. As an exception, GH. at first increases with LET, reaching a maximum near 6.5 keV/µm before decreasing steeply at higher LET. The results obtained are generally in good agreement with available experimental data over the whole acidity and LET ranges studied. Finally, as an application, we have simulated the radiation-induced oxidation of ferrous sulfate solutions in aerated aq. 0.4 mol/L H2SO4 (Fricke dosimeter) as a function of time up to ~50 s and addressed the effects of LET on the resulting ferric ion yield at 25 °C. The production of Fe3+ ions is highly sensitive to free-radical yields, especially H atoms (via formation of HO2), resulting in a marked decline of G(Fe3+) with increasing LET. The general trend of the observed variation of G(Fe3+) with radiation quality is well reproduced by our computed Fe3+ ion yield values.Key words: liquid water, acidic (H2SO4) aqueous solutions, radiolysis, free-radical and molecular yields, linear energy transfer (LET), Fricke dosimeter, Monte Carlo simulations.
The natural bite angle — Seen from a ligand's point of view
Authors: Kühl Olaf
Published: April 2007

The natural bite angle concept is examined using N,N′-bisphosphino urea ligands as rigid scaffolds. The ligand has an upper limit of about 95° for the observed bite angle in chelate complexes, but prefers a much lower one. The ligand can be described as possessing downward flexibility. The dependence of the bite angle on the P—P distance within the ligand and the M—P bond length is illustrated. The metal tries to force the ligand into its own preferred structure, whereas the ligand wants to achieve a short P—P distance. A truly rigid ligand such as the N,N′-bisphosphino urea family is thus seen to clearly discriminate between metal atoms according to their individual assertiveness, using the P—P distance in the complex as a measure. Although the natural bite angle concept is valid and helpful in determining the possible bite-angle range for ligands before it is actually synthesised, its practical applicability seems to be limited to those cases where the flexibility range of the ligand allows for only one metal-preferred bite angle to be realized.Key words: natural bite angle, ligand effects, ligand design.
SYNCHRONIZATION OF LIMIT SETS
Authors: LI CHANGPIN , DENG WEIHUA
Published: April 2007

In this paper, we derive a sufficient condition of synchronizing limit sets (attractors and repellers) by using the linear feedback control technique proposed here. Several examples are included. The numerical simulations and computer graphics show that our method works well.
ONE-DIMENSIONAL NON-SYMMETRIC WIDOM–ROWLINSON MODEL WITH LONG-RANGE INTERACTION
Authors: KERIMOV AZER
Published: April 2007

The absence of phase transitions in one-dimensional Widom–Rowlinson model with long-range interaction is established in the non-symmetric case when different particles have different activity parameters.
A REMARK ON RASMUSSEN'S INVARIANT OF KNOTS
Authors: MACKAAY MARCO , TURNER PAUL , VAZ PEDRO
Published: April 2007

We show that Rasmussen's invariant of knots, which is derived from Lee's variant of Khovanov homology, is equal to an analogous invariant derived from certain other filtered link homologies.
FUNCTION PREDICTION OF UNCHARACTERIZED PROTEINS
Authors: HAWKINS TROY , KIHARA DAISUKE
Published: April 2007

Function prediction of uncharacterized protein sequences generated by genome projects has emerged as an important focus for computational biology. We have categorized several approaches beyond traditional sequence similarity that utilize the overwhelmingly large amounts of available data for computational function prediction, including structure-, association (genomic context)-, interaction (cellular context)-, process (metabolic context)-, and proteomics-experiment-based methods. Because they incorporate structural and experimental data that is not used in sequence-based methods, they can provide additional accuracy and reliability to protein function prediction. Here, first we review the definition of protein function. Then the recent developments of these methods are introduced with special focus on the type of predictions that can be made. The need for further development of comprehensive systems biology techniques that can utilize the ever-increasing data presented by the genomics and proteomics communities is emphasized. For the readers' convenience, tables of useful online resources in each category are included. The role of computational scientists in the near future of biological research and the interplay between computational and experimental biology are also addressed.
SEAM: A STOCHASTIC EM-TYPE ALGORITHM FOR MOTIF-FINDING IN BIOPOLYMER SEQUENCES
Authors: BI CHENGPENG
Published: April 2007

Position weight matrix-based statistical modeling for the identification and characterization of motif sites in a set of unaligned biopolymer sequences is presented. This paper describes and implements a new algorithm, the Stochastic EM-type Algorithm for Motif-finding (SEAM), and redesigns and implements the EM-based motif-finding algorithm called deterministic EM (DEM) for comparison with SEAM, its stochastic counterpart. The gold standard example, cyclic adenosine monophosphate receptor protein (CRP) binding sequences, together with other biological sequences, is used to illustrate the performance of the new algorithm and compare it with other popular motif-finding programs. The convergence of the new algorithm is shown by simulation. The in silico experiments using simulated and biological examples illustrate the power and robustness of the new algorithm SEAM in de novo motif discovery.
COMPUTING THE REVERSAL DISTANCE BETWEEN GENOMES IN THE PRESENCE OF MULTI-GENE FAMILIES VIA BINARY INTEGER PROGRAMMING
Authors: SUKSAWATCHON JAKKARIN , LURSINSAP CHIDCHANOK , BODÉN MIKAEL
Published: April 2007

Hannenhalli and Pevzner developed the first polynomial-time algorithm for the combinatorial problem of sorting signed genomic data. Their algorithm determines the minimum number of reversals required for rearranging a genome to another — but only in the absence of gene duplicates. However, duplicates often account for 40% of a genome. In this paper, we show how to extend Hannenhalli and Pevzner's approach to deal with genomes with multi-gene families. We propose a new heuristic algorithm to compute the nearest reversal distance between two genomes with multi-gene families via binary integer programming. The experimental results on both synthetic and real biological data demonstrate that the proposed algorithm is able to find the reversal distance with high accuracy.
METABOLIC PATHWAY ANALYSIS OFS. PNEUMONIAE: ANIN SILICOAPPROACH TOWARDS DRUG-DESIGN
Authors: SINGH SHAILZA , MALIK B. K. , SHARMA D. K.
Published: April 2007

The emergence of multidrug resistant varieties of Streptococcus pneumoniae (S. pneumoniae) has led to a search for novel drug targets. An in silico comparative analysis of metabolic pathways of the host Homo sapiens (H. sapiens) and the pathogen S. pneumoniae have been performed. Enzymes from the biochemical pathways of S. pneumoniae from the KEGG metabolic pathway database were compared with proteins from the host H. sapiens, by performing a BLASTp search against the non-redundant database restricted to the H. sapiens subset. The e-value threshold cutoff was set to 0.005. Enzymes, which do not show similarity to any of the host proteins, below this threshold, were filtered out as potential drug targets. Five pathways unique to the pathogen S. pneumoniae when compared to the host H. sapiens have been identified. Potential drug targets from these pathways could be useful for the discovery of broad-spectrum drugs. Potential drug targets were also identified from pathways related to lipid metabolism, carbohydrate metabolism, amino acid metabolism, energy metabolism, vitamin and cofactor biosynthetic pathways and nucleotide metabolism. Of the 161 distinct targets identified from these pathways, many are in various stages of progress at the Microbial Genome Database. However, 44 of the targets are new and can be considered for rational drug design. The study was successful in listing out potential drug targets from the S. pneumoniae proteome involved in vital aspects of the pathogen's metabolism, persistence, virulence and cell wall biosynthesis. This systematic evaluation of metabolic pathways of host and pathogen through reliable and conventional bioinformatics approach can be extended to other pathogens of clinical interest.
ENTREPRENEURSHIP AND ECONOMIC GROWTH: AN EMPIRICAL ANALYSIS
Authors: SALGADO-BANDA HÉCTOR
Published: April 2007

This study examines the impact of entrepreneurship on economic growth by using a new variable based on patent data to proxy for productive entrepreneurship. Data on self-employment is used as an alternative proxy. The study considers 22 OECD countries and finds a positive relationship between the proposed measure of productive entrepreneurship — degree of innovativeness of different nations — and economic growth, while the alternative measure, based on self-employment, appears to be negatively correlated with economic growth. A battery of econometric specifications and techniques backs the findings.
ENTREPRENEURSHIP AND ETHNICITY: THE ROLE OF HUMAN CAPITAL AND FAMILY SOCIAL CAPITAL
Authors: SIQUEIRA ANA CRISTINA O.
Published: April 2007

This study of Brazilian immigrants in the United States examines the extent to which the human capital and the family social capital theories explain the probability of owning a business. This study incorporates into the analytical models a variable that controls for the presence of a market niche and tests for the net effects of human and family social capital. Analyses of U.S. 2000 Census data find that high school graduates are more likely to own their own business and that a college education exerts a significantly larger effect than that of a high school education on the probability of owning a business. Additionally, the presence of a co-habiting spouse, treated as an indicator of family social capital, enhances the probability that immigrants will own their own establishment. The results support the human capital and the family social capital theories. The study discusses implications for theory and future research.
ENTREPRENEURSHIP DEVELOPMENT: SMES IN INDONESIA
Authors: TAMBUNAN TULUS
Published: April 2007

The Indonesian government has been trying to encourage entrepreneurship development by supporting the development of small and medium enterprises in the country, since these enterprises provide an avenue for the testing and development of entrepreneurial ability. This paper examines the current developments of SMEs in the country. The paper comes with a number of interesting facts. First, SMEs are of overwhelming importance in Indonesia, as they account for more than 90 percent of all firms outside the agricultural sector, and thus are the biggest source of employment. Second, the representation of women entrepreneurs is low. Third, women entrepreneurs are less educated than their men counterparts. Fourth, the main constraints faced by small entrepreneurs are lack of working capital and marketing difficulties. Finally, the majority of existing studies suggest that the effectiveness of government programs to support SME development programs is low. The paper concludes that in national efforts to develop high competitive entrepreneurships, owners of small enterprises should be given the first priority as they have some previous experience of running a business or of how to survive in competitive markets, and the emphasis should be to promote modernization, capacity building and size upgrading.