bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogeny of the genusLotus(Leguminosae, Loteae): evidence from nrITS sequences and morphology
Authors: Degtjareva G.V. , Kramina T.E. , Sokoloff D.D. , Samigullin T.H. , Valiejo-Roman C.M. , Antonov A.S.
Published: August 2006

Lotus (120–130 species) is the largest genus of the tribe Loteae. The taxonomy of Lotus is complicated, and a comprehensive taxonomic revision of the genus is needed. We have conducted phylogenetic analyses of Lotus based on nrITS data alone and combined with data on 46 morphological characters. Eighty-one ingroup nrITS accessions representing 71 Lotus species are studied; among them 47 accessions representing 40 species are new. Representatives of all other genera of the tribe Loteae are included in the outgroup (for three genera, nrITS sequences are published for the first time). Forty-two of 71 ingroup species were not included in previous morphological phylogenetic studies. The most important conclusions of the present study are (1) addition of morphological data to the nrITS matrix produces a better resolved phylogeny of Lotus; (2) previous findings that Dorycnium and Tetragonolobus cannot be separated from Lotus at the generic level are well supported; (3) Lotus creticus should be placed in section Pedrosia rather than in section Lotea; (4) a broad treatment of section Ononidium is unnatural and the section should possibly not be recognized at all; (5) section Heinekenia is paraphyletic; (6) section Lotus should include Lotus conimbricensis; then the section is monophyletic; (7) a basic chromosome number of x = 6 is an important synapomorphy for the expanded section Lotus; (8) the segregation of Lotus schimperi and allies into section Chamaelotus is well supported; (9) there is an apparent functional correlation between stylodium and keel evolution in Lotus.
Plant diversity, composition, and rarity in the southern boreal peatlands of Manitoba, Canada
Authors: Locky David A. , Bayley Suzanne E.
Published: August 2006

Plant diversity and rarity have been relatively well studied for bryophytes in Canadian western boreal peatlands, but little information exists for vascular plants. Diversity, community composition, and rarity of bryophytes and vascular plants were determined and relationships examined among these and environmental variables in five peatland types at Duck Mountain, Manitoba: wooded bogs, black spruce swamps, wooded moderate-rich fens, open moderate-rich fens, and open extreme-rich fens. Total diversity was 298 species comprising 86 bryophytes and 212 vascular plants. Mean diversity followed a unimodal distribution over a bog – rich fen gradient. Wooded moderate-rich fens (59.0) and black spruce swamps (53.4) had the highest mean diversity, whereas wooded bogs (32.3) and open extreme-rich fens (34.7) had the lowest mean diversity. Occurrences of locally rare species followed the same general pattern, and provincially rare vascular plants were found primarily in wooded moderate-rich fens and black spruce swamps and were mostly orchids. Reasons for these patterns are complex, but high diversity appears to be related to high habitat heterogeneity and moderate environmental variables, e.g., pH and alkalinity, and low diversity appears to be related to environmental extremes, e.g., pH and alkalinity. Boreal wooded moderate-rich fens and black spruce swamps have comparatively high plant diversity and rarity and require consideration if the focus is biodiversity conservation. This will become increasingly important in landscapes where development pressures are high.
High-quality and homogeneous Arabidopsis thaliana plants from a simple and inexpensive method of hydroponic cultivation
Authors: Robison Mary M. , Smid Matthew P.L. , Wolyn David J.
Published: August 2006

A methodology is presented for the hydroponic cultivation of Arabidopsis thaliana (L.) Heynh. that is simple and inexpensive to construct from easily obtainable and reusable materials. High-quality and uniform plant material, free of algae and disease, are consistently produced through all life-stages. Minor modifications to previous protocols that reduce cost and labour include the use of small food-storage containers with snap-on lids, aluminum foil wrap to cover the containers to occlude light, commercial hydroponic fertilizer as nutrient solution, and clipped 1.5 mL microfuge tubes as plug holders. Seed is germinated on nutrient agar plates, instead of directly on rockwool plugs; after the seedlings have grown to the six-leaf stage, they are removed from the plates and the roots are enclosed within rockwool plugs that have been cut longitudinally. Subsequent seedling growth is very uniform and the elimination of oversowing and subsequent thinning results in a dramatic reduction in seed and seedling wastage.
Effects of wild rice (Zizania palustris) straw on biomass and seed production in northern Minnesota
Authors: Durkee Walker Rachel , Pastor John , Dewey Bradley W.
Published: August 2006

Wild rice ( Zizania palustris L.) litter accumulation may inhibit plant growth and production both by physically suppressing seedling emergence and by nitrogen immobilization in fresh litter. This latter mechanism could reduce nitrogen availability to plants early in the growing season at a period when more than half of the annual uptake occurs. To test the importance of these mechanisms, we planted wild rice in mesocosms. Half the tanks were planted with seeds sown below the litter and half were planted with seedlings grown to a height taller than litter thickness. One-third of the tanks were treated with fresh (nitrogen immobilizing) litter, one-third were treated with litter that had been incubated for 26 d and was mineralizing nitrogen, and one-third did not receive litter. These treatments resulted in a fully crossed factorial design, with nine replicates for each treatment combination, totaling 54 tanks. We measured plant growth, vegetative, root, and seed biomass, total plant N, and available N at 2.5 cm sediment depth. The presence of litter and its stage of decay caused plant, root, and seed biomass, and seed and total plant nitrogen content to increase. We found no physical inhibition of litter on the potential growth of plants started as seeds. Therefore, the timing of litter nitrogen immobilization or mineralization affects the potential growth of wild rice.
Identification of two genera of N2-fixing cyanobacteria growing on three feather moss species in boreal forests of Quebec, Canada
Authors: Houle Daniel , Bilodeau Gauthier Simon , Paquet Serge , Planas Dolors , Warren Annabelle
Published: August 2006

The recent discovery that N2fixation rates by the feather moss carpet of boreal Scandinavian forests increases with stand maturity has put into question the paradigm that N2fixation is negligible in mature boreal forest. The N2fixation was attributed to a previously unknown association between Nostoc sp., a N2-fixing cyanobacteium and Pleurozium schreberi (Brid.) Mitt., a feather moss that is abundant worldwide in the boreal forest. Here we report for the first time that this association also exists in the Canadian boreal forest. We discovered, however, that Nostoc was found growing not only on Pleurozium but also on two other moss species ( Hylocomnium splendens (Hedw.) Br. Eur. and Ptillium crista-castrensis (Hedw.) De Not.). In addition, the N2-fixing cyanobacterium Stigonema sp. was observed on the three moss species mentioned above, indicating the existence of six different associations. At least one of the six associations was found at 9 of 13 sites that are representative of a large area of the Quebec boreal forest. These findings suggest possibilities for further research, aimed at measuring the unaccounted for N2-fixing potential of the feather moss carpet in Canadian boreal forests.
A PCR-based method to detect species of Gondwanamyces and Ophiostoma on surfaces of insects colonizing Protea flowers
Authors: Roets Francois , Wingfield Michael J. , Dreyer Léanne L. , Crous Pedro W. , Bellstedt Dirk U.
Published: August 2006

Flower heads of economically important members of the genus Protea L. mature into conspicuous, often long-lived infructescences, which in South Africa are commonly colonized by species of the ophiostomatoid fungi Gondwanamyces G.J. Marais & M.J. Wingfield and Ophiostoma Syd. & P. Syd. It is suspected that these fungi are transported between infructescences by insects. To develop techniques that would enable detection of ophiostomatoid fungi on insects, primers GPR1 and OSP1 were designed based on unique 28S ribosomal DNA sequences of Gondwanamyces and Ophiostoma from Protea. Multiplex polymerase chain reaction of these primers, combined with universal primer LR6, yielded fragment lengths of 885 and 637 bp. Positive amplification was achieved from as little as 30 and 45 pg of fungal genomic DNA for Gondwanamyces and Ophiostoma, respectively, and fragments of identical lengths were amplified from insects artificially inoculated with these fungi. No other tested fungal species showed amplification with GPR1 or OSP1 and LR6. Using these primers two insect species ( Genuchus hottentottus Fabricius and Oxycarenus maculates Stal.) collected from Protea repens L. infructescences were confirmed as carriers of Gondwanamyces proteae (M.J. Wingfield et al.) G.J. Marais & M.J. Wingfield and Ophiostoma splendens G.J. Marais & M.J. Wingfield, respectively. The method developed in this study represents a rapid detection system that can be used to understand the relationship between insects and ophiostomatoid fungi found associated with flowers of South African species of Protea .
Anomalous early 20th century sedimentation in proglacial Green Lake, British Columbia, Canada
Authors: Menounos Brian
Published: August 2006

Annually laminated sediments were recovered from Green Lake, a proglacial lake in the southern Coast Mountains in British Columbia, to examine their potential as a temperature proxy. Varve thickness is moderately correlated with temperature anomalies (A.D. 1900–1994) and annual maximum mean daily discharge of Lillooet River (A.D. 1930–1999), but these relations are not stable through time. Following A.D. 1977, the relation between varve thickness and annual maximum mean daily discharge is stronger. Prior to A.D. 1977, varve thickness is correlated with March to October air temperature, which controls the intensity and duration of glacier runoff. Varve thickness is weakly correlated with reconstructed air temperature records for North America and the Northern Hemisphere for the period A.D. 1600–1976. Less extensive glacier cover may explain the lack of a clear temperature signal in the varved sediment record prior to A.D. 1600 and following A.D. 1977. The period of highest lake sedimentation, from A.D. 1920 to 1945, coincides with rapid retreat of glaciers in the watershed. The lack of a similar level of sedimentation in the varve chronology suggests that glacier recession during the period 1920–1945 was higher than at any time in the past 600 years.
A possible egg of the dromaeosaurDeinonychus antirrhopus: phylogenetic and biological implications
Authors: Grellet-Tinner Gerald , Makovicky Peter
Published: August 2006

A unique find of a partial egg in contact with articulated gastralia from a known specimen of the dromaeosaurid Deinonychus antirrhopus (AMNH 3015) is described. Much of the original taphonomic context of the specimen was lost during the 1931 excavation and preparation, but enough information is preserved to provide strong evidence for a parental association between the adult skeleton and egg. The articulated nature of the gastralia suggests that the adult skeleton was at least partially articulated and had not suffered from either extensive subaerial exposure or postmortem transport, and the egg preservation also indicates in situ burial and postburial lithogenic crushing. Additional support stems from the presence of limey claystone matrix that indicates a low-energy depositional event. Phylogenetic characteristics of the eggshell microstructure are consistent with a theropod origin, and skeletochronological analysis suggests that AMNH 3015 was an adult and thus of breeding age bolstering the interpretation that the egg derives from the skeletal specimen. Physiological parameters of D. antirrhopus, such as estimated mass and pelvic canal diameter, as well as eggshell thickness, are very similar to the similar sized and closely related oviraptorid Citipati osmolskae. Closely related maniraptoran theropods of several species have been found brooding their nests with the gastralia close to or in contact with eggs, and such a scenario is consistent with the preservation of AMNH 3015. Alternative explanations to a parental association, such as random co-occurrence or feeding, are improbable given the taphonomic and biological data of the find. AMNH 3015, therefore, probably represents the first identifiable dromaeosaurid egg yet discovered. It shares derived characters such as two eggshell layers with other theropods. Within theropods, the AMNH 3015 eggshell shares derived characteristics with oviraptorids and differs from troodontid eggshell despite the fact that these taxa are often recovered as sister groups in analyses of skeletal characters, but this signal is weak.
Ecological differences between two closely related morphologically similar benthic whitefish(Prosopium spilonotusandProsopium abyssicola) in an endemic whitefish complex
Authors: Kennedy Benjamen M , Thompson Brett W , Luecke Chris
Published: August 2006

Identifying the differences in ecology between closely related species occupying the same environment contributes to our understanding of community diversity, ecosystem structure, and species conservation. Endemic Bear Lake whitefish (Prosopium abyssicola) and Bonneville whitefish (Prosopium spilonotus) are benthic, morphologically similar, and closely related, yet the extent of differential resource use remains poorly understood. To determine the ecological differences between these two species, we studied their seasonal distribution and diet in Bear Lake, Utah–Idaho. We used bottom-set gill nets to examine how catch of each species of whitefish varied in relation to depth and season (spring and summer). In both spring and summer, Bonneville whitefish dominated the shallower depths (5–30 m), whereas Bear Lake whitefish dominated the deeper depths (45–55 m). Bonneville whitefish ate a variety of benthic invertebrates, but mostly Chironomidae, whereas Bear Lake whitefish fed mostly on Ostracoda. These data describe a closely related morphologically similar, yet ecologically distinct group of whitefish in an ecoregion completely different from those studied before. These results indicated that each species has a very different role in the Bear Lake ecosystem. To conserve this unique fish assemblage, both shallow and deepwater habitats need to be protected.
Route selection in a large river during the homing migration of Chinook salmon (Oncorhynchus tshawytscha)
Authors: Keefer Matthew L , Caudill Christopher C , Peery Christopher A , Bjornn Theodore C
Published: August 2006

Upstream-migrating adult salmon must make a series of correct navigation and route-selection decisions to successfully locate natal streams. In this field study, we examined factors influencing migration route selections early in the migration of 4361 radio-tagged adult Chinook salmon (Oncorhynchus tshawytscha) as they moved upstream past dams in the large (~1 km wide) Columbia River. Substantial behavioral differences were observed among 11 conspecific populations, despite largely concurrent migrations. At dams, Chinook salmon generally preferred ladder passage routes adjacent to the shoreline where their natal tributaries entered, and the degree of preference increased as salmon proximity to natal tributaries increased. Columbia River discharge also influenced route choices, explaining some route selection variability. We suggest that salmon detect lateral gradients in orientation cues across the Columbia River channel that are entrained within tributary plumes and that these gradients in cues can persist downstream for tens to hundreds of kilometres. Detection of tributary plumes in large river systems, using olfactory or other navigation cues, may facilitate efficient route selection and optimize energy conservation by long-distance migrants.
Characterization of phosphorus in sequential extracts from lake sediments using 31P nuclear magnetic resonance spectroscopy
Authors: Reitzel Kasper , Ahlgren Joakim , Gogoll Adolf , Jensen Henning S , Rydin Emil
Published: August 2006

Phosphorus (P) compounds in three different lake surface sediments were extracted by sequential P extraction and identified by 31P nuclear magnetic resonance (31P NMR) spectroscopy. The extraction procedure primarily discriminates between inorganic P-binding sites but most extraction steps also contained P not reacting (nrP) with the molybdenum complex during P analyses. In all three lakes, the nrP dominated in the NaOH extracts. Nonreactive P from the dystrophic lake was dominated by potentially recalcitrant P groups such as orthophosphate monoesters, while the nrP in the two more productive lakes also contained polyphosphates, pyrophosphate, and organic P groups such as P lipids and DNA-P that may be important in remineralization and recycling to the water column. In addition, polyphosphates showed substantial dynamics in settling seston. The Humic-P pools (P associated with humic acids) showed strong signals of orthophosphate monoesters in all three lakes, which supported the assumption that P-containing humic compounds are indeed recovered in this fraction, although other organic P forms are also present. Thus, in addition to expanding the understanding of which organic P forms that are present in lake sediments, the 31P NMR technique also demonstrated that the chemical extraction procedure may provide some quantification of recalcitrant versus labile organic P forms.
Stable hydrogen isotopic composition of fishes reflects that of their environment
Authors: Whitledge Gregory W , Johnson Brett M , Martinez Patrick J
Published: August 2006

Otolith microchemistry and isotopic analyses have emerged as effective techniques for providing insights into fish environmental history that are difficult to obtain by other means. Stable hydrogen isotope ratio (2H/1H or D/H, expressed as δD) is a possible environmental marker that has not been employed in fish provenance research, although it has been applied as a natural tracer of terrestrial organism migrations. We illustrate the potential of δD to serve as a new natural marker of fish environmental history by demonstrating that significant linear relationships (r2 ≥ 0.97) exist between fish otolith and muscle δD and δD of waters that fish inhabit. Differences between mean water δD and both muscle and otolith δD were not significantly correlated with fish total length and were not significantly different among species, indicating that water–fish δD relationships are consistent across fish sizes and species. High r2 values for regressions of otolith and muscle δD on water δD for fishes inhabiting locations with diverse thermal regimes suggest that relationships between water and fish δD are not strongly affected by water temperature. Demonstration that fish δD clearly reflects water δD provides a foundation for future research to reconstruct fish movement among locations with distinct δD signatures.
Bioenergetics and mercury dynamics in fish: a modelling perspective
Authors: Trudel Marc , Rasmussen Joseph B
Published: August 2006

The concentration of mercury in fish generally increases with age and size. Although a number of hypotheses have been invoked to explain this pattern, our understanding of the processes regulating the accumulation of mercury in fish is currently inadequate. In this study, we used a simple mass balance model to explore how the relationship between mercury concentration and fish age is affected by bioenergetics processes and prey contamination. We show that mercury concentration increases with fish age when older fish consume more contaminated prey or when metabolic costs associated with activity also increase with fish size. Our analyses further indicate that the relative importance of growth rate, activity costs, and consumption rates for mercury concentration can vary widely. We also show that changes in the energy density of fish and their prey with fish size could also affect the relationship between mercury concentration in fish and age. Application of this mass balance model indicates that bioenergetics models underestimate the activity costs of lake trout. A simple approach is presented to estimate activity costs of fish under field conditions.
Numerical simulations of a viscous-fingering instability in a fluid with a temperature-dependent viscosity
Authors: Holloway Kristi E , Bruyn John R
Published: August 2006

We have performed numerical simulations of the flow of hot glycerine as it displaces colder, more viscous glycerine in a radial Hele–Shaw cell. We find that fingering occurs for sufficiently high inlet velocities and viscosity ratios. The wavelength of the instability is independent of inlet velocity and viscosity ratio, but depends weakly on cell width. The growth rate of the fingers is found to increase with inlet velocity and decrease with the cell width. We compare our results with those from experiments.PACS No.: 47.54.–r
Projectile motion in the “exponential atmosphere”: approximate trajectories
Authors: Mohazzabi Pirooz , Lerro Tarisa N
Published: August 2006

Approximate trajectories for projectile motion in an “exponential atmosphere” are discussed. It is shown that for low speeds (compared with the speed of sound) an excellent fit of the data can be accomplished with a two-parameter quartic equation as well as an earlier-suggested three-parameter cubic equation. For high-speed projectiles launched at low angles (compared with 45°) these models are insufficient and more terms must be added in each case. High-speed projectiles launched at high projection angles, on the other hand, can be very accurately modeled by parabolic trajectories.PACS No.: 45.50.Dd
Production of intense radioactive beams at ISAC using low-energy protons
Authors: Trinczek M , Lapi S , Guo B , Ames F , Buckley K R , D'Auria J M , Jayamanna K , Liu W P , Ruiz C , Ruth T J
Published: August 2006

A proof-of-principle approach for the production of intense (~108/s) radioactive ion beams, which differs from the standard ISOL (Isotope Separation On-Line) technique, has been demonstrated successfully using 11C at the TRIUMF laboratory. This approach uses 13 MeV protons produced by a medical cyclotron and should be useful for a range of radioisotopes of interest to the nuclear astrophysics research programme.PACS No.: 29.25.Rm
Electrodynamics of a magnet moving through a conducting pipe
Authors: Partovi M Hossein , Morris Eliza J
Published: August 2006

The popular demonstration involving a permanent magnet falling through a conducting pipe is treated as an axially symmetric boundary-value problem. Specifically, Maxwell's equations are solved for an axially symmetric magnet moving coaxially inside an infinitely long, conducting cylindrical shell of arbitrary thickness at nonrelativistic speeds. Analytic solutions for the fields are developed and used to derive the resulting drag force acting on the magnet in integral form. This treatment represents a significant improvement over existing models, which idealize the problem as a point dipole moving slowly inside a pipe of negligible thickness. It also provides a rigorous study of eddy currents under a broad range of conditions, and can be used for magnetic braking applications. The case of a uniformly magnetized cylindrical magnet is considered in detail, and a comprehensive analytical and numerical study of the properties of the drag force is presented for this geometry. Various limiting cases of interest involving the shape and speed of the magnet and the full range of conductivity and magnetic behavior of the pipe material are investigated and corresponding asymptotic formulas are developed.PACS Nos.: 81.70.Ex, 41.20.–q, 41.20.Gz
Settlement analysis of pile groups in layered soils
Authors: Cairo Roberto , Conte Enrico
Published: August 2006

This paper presents a method to perform a nonlinear analysis of pile groups subject to vertical loading. The method makes use of the dynamic stiffness matrices to simulate the response of layered soils. These matrices are incorporated in a calculation procedure that is computationally very efficient because the response of a pile group can be achieved using essentially the solution for a single pile. The method is first used to perform a linear elastic analysis of pile groups and is then extended to include the nonlinearity effects. In this context, the widely accepted approach is adopted in which nonlinearity is considered to be confined in a narrow zone close to each pile, whereas outside this zone the soil is assumed to behave as a linear elastic medium. Moreover, a global interaction factor is introduced to account for the interaction among the piles in the group. The theoretical predictions from the proposed method are compared with experimental measurements from several published full-scale and model tests on pile groups loaded up to failure. The agreement between predicted and observed behaviour is found to be very satisfactory, even approaching the ultimate load, when the results of loading tests on single piles are available and the group efficiency with respect to the failure load is close to unity.Key words: pile groups, settlement analysis, nonlinear behaviour, layered soils.
Limit analysis of submerged slopes subjected to water drawdown
Authors: Viratjandr Chardphoom , Michalowski Radoslaw L
Published: August 2006

A rapid draw of water from a reservoir can cause a temporary increase in the hydraulic gradient that may not be tolerated by the slope of an earth dam. The increased seepage forces may lead to slope instability, causing the collapse of the structure. The kinematic approach of limit analysis is used to examine stability of slopes subjected to a rapid or slow drawdown. Combinations of slope inclination, soil properties, and hydraulic conditions are found for which the slope becomes unstable. The results are presented in the form of charts for convenient practical use, and the safety factors can be obtained from the charts without the need for iteration. For granular slopes, particularly if shallow, subjected to drawdown, a simple translational mechanism with a shallow failure surface is not the most adverse mechanism for all water-draw regimes.Key words: slopes, stability, rapid drawdown, limit state analysis.
Predicting the unsaturated hydraulic conductivity of granular soils from basic geotechnical properties using the modified Kovács (MK) model and statistical models
Authors: Mbonimpa M , Aubertin M , Bussière B
Published: August 2006

The water retention curve (WRC) is often used to define the relative hydraulic conductivity, kr, of unsaturated soils. In this paper, the authors propose the use of the modified Kovács (MK) model, developed to predict the WRC using basic geotechnical properties, combined with some existing statistical models to estimate the kr function. The proposed equations are implemented in MATLAB®. After a preliminary validation based on comparisons with existing solutions, predictive results are presented for granular soils. These indicate a relatively good agreement with experimental results from drainage tests taken from the literature. A discussion follows on the advantages and limitations of the proposed approach.Key words: water retention curve, unsaturated hydraulic conductivity, predictive models, granular soils.
Limit states and reliability-based design for a non-codified problem of aqueduct buoyancy
Authors: Robinson Gil , Graham James , Skaftfeld Ken , Sorokowski Ron
Published: August 2006

Limit states design methods and engineering judgement have been used to assess buoyancy issues for remediation of the 85 year old Shoal Lake Aqueduct in Manitoba. The study demonstrates how these methods can be applied to non-codified engineering problems. Four separate buoyancy analyses were completed using (i) partial safety factors from the Ontario Highway Bridge Design Code, (ii) project-specific partial safety factors, (iii) Monte Carlo simulation techniques, and (iv) working stress design (WSD) methods. Engineering judgement was required to develop a buoyancy model, interpret data for modeling parameters, and provide meaningful values for parameters that could not be measured. Results from the analyses show that more uniform reliability is provided when measured variability of the model parameters is accounted for. The reliability is not quantifiable when working stress design methods are used. Key words: limit states, probability, non-codified problem, aqueduct, buoyancy.
The ultimate pullout capacity of anchors in frictional soils
Authors: Merifield R S , Sloan S W
Published: August 2006

During the last 30 years various researchers have proposed approximate techniques to estimate the uplift capacity of soil anchors. As the majority of past research has been experimentally based, much current design practice is based on empiricism. Somewhat surprisingly, very few numerical analyses have been performed to determine the ultimate pullout loads of anchors. This paper presents the results of a rigorous numerical study to estimate the ultimate pullout load for vertical and horizontal plate anchors in frictional soils. Rigorous bounds have been obtained using two numerical procedures that are based on finite element formulations of the upper and lower bound theorems of limit analysis. For comparison purposes, numerical estimates of the break-out factor have also been obtained using the more conventional displacement finite element method. Results are presented in the familiar form of break-out factors based on various soil strength profiles and geometries and are compared with existing numerical and empirical solutions.Key words: anchor, pullout capacity, finite elements, limit analysis, lower bound, sand.
SIGNAL-PATH-LEVEL DUAL-Vt ASSIGNMENT FOR LEAKAGE POWER REDUCTION
Authors: WANG YU , YANG HUAZHONG , WANG HUI
Published: August 2006

Along with the fast development of dual-threshold voltage (dual-Vt) and multi-threshold technology, it is possible to use them to reduce static power in low-voltage high-performance circuits. In this paper, we propose a new method to realize CMOS digital circuits that are implemented with dual-Vt technology. We first present a new signal-path-level circuit model which effectively deals with the fact that there can be two threshold voltages assigned to a single gate. In order to assign proper threshold voltage to all the signal-paths in the circuit, our new algorithms introduce the concept of subcircuit extraction and include the hierarchy algorithms which are effective and fast. Experimental results show that our algorithms produce a significant reduction for the ISCAS85 benchmark circuits.
MEMORY ACCESS DRIVEN STORAGE ASSIGNMENT FOR VARIABLES IN EMBEDDED SYSTEM DESIGN
Authors: CHOI YOONSEO , KIM TAEWHAN
Published: August 2006

In this paper, we address the DRAM storage assignment problems of variables with an objective of maximizing the number of page/burst mode accesses. Specifically, (1) we solve the problem of variable alignment to memory for maximizing the use of page accesses by proposing a technique, called zone_alignment, which is based on the combination of an efficient 0-1 ILP (integer linear programming) formulation and the utilization of temporal locality of variables' accesses in code and (2) the approach used in (1) is then applied to solve the problem of variable alignment for maximizing the use of burst accesses. Surprisingly, the execution of the ILP formulation used in (2) is relatively much faster than that used in (1) and nevertheless, the (optimal) formulation in (2) produces much better results than that by the existing techniques whereas the (optimal) formulation in (1) produces almost the same or slightly improved results, indicating that the problem with page accesses and the problem with burst accesses must be treated completely separately. (3) Finally, by utilizing the techniques in (1) and (2), we propose solutions to two extended DRAM architectures: (a) DRAMs with the capability of both of page and burst access modes and (b) DRAMs with multiple banks. We provide a set of experimental data to show the effectiveness of the proposed techniques.
CMOS EVEN HARMONIC SWITCHING MIXER FOR DIRECT CONVERSION RECEIVERS
Authors: LIU J. J. , DO M. A. , YU X. P. , YEO K. S. , JIANG S. , MA J. G.
Published: August 2006

DC offset and high flicker noise are the main problems for the direct conversion CMOS mixer design. A novel even harmonic switching mixer implemented in a standard 0.18 μm CMOS process for applications in 2.45 GHz direct conversion receivers is proposed. The mixer circuit overcomes the problems of DC offset and high flicker noise. It achieves -8.24 dB gain, 5.2 dB DSB noise figure at 100 KHz, 17.25 dBm IIP3 and zero DC power consumption.
SYSTEM RELIABILITY OF A STOCHASTIC-FLOW NETWORK WITH NODES HAVING CAPACITY AND COST ATTRIBUTES
Authors: LIN YI-KUEI
Published: August 2006

A stochastic-flow network in which nodes as well as arcs all have both capacity and cost attributes is studied. We evaluate the possibility that the maximum flow of the network is not less than a demand under the budget constraint. Such a possibility is in general called the system reliability. A minimal path, an order sequence of arcs & nodes from the source to the sink without cycles, is used to assign the flow to each component (arc or node). Based on minimal paths, an efficient algorithm is proposed to generate all (d, C)-MPs that are the minimal capacity vectors meeting the demand d and the budget C. The system reliability can then be calculated in terms of all (d, C)-MPs.
ON A MEASURE OF RELIABILITY BASED ON POINT PROCESSES WITH RANDOM FUZZY MARKS
Authors: ZEEPHONGSEKUL P.
Published: August 2006

This paper considers the problem faced by a reliability analyst who has detected faults in a system, which were caused by a combination of random and systematic factors. Such faults usually occur at random points in space or time. The analyst's challenge is to accurately gauge the scale of the problem, accepting the fact that an appropriate reliability estimate must also take into consideration the subjective nature of her assessment. In this paper, we introduce a reliability measure, which we called a gauge measure, which incorporates the randomness due to the locations of the faults as well as the imprecision caused by the subjective nature of the assessment. The randomness of the locations will be modeled by a point process and the subjective assessment of each fault by a random fuzzy mark. The mean and variance of a gauge measure will be obtained. Finally, through a generic example and several real world applications, we show how this measure can be applied to measure the reliability of many occurring working systems, especially software systems.
Design and Progress of a Trial of Selenium to Prevent Prostate Cancer among Men with High-Grade Prostatic Intraepithelial Neoplasia
Authors: Marshall James R. , Sakr Wael , Wood David , Berry Donna , Tangen Catherine , Parker Felicia , Thompson Ian , Lippman Scott M. , Lieberman Ronald , Alberts David , Jarrard David , Coltman Charles , Greenwald Peter , Minasian Lori , Crawford E. David
Published: August 2006

High-grade prostatic intraepithelial neoplasia (HGPIN) is generally regarded as a premalignant lesion that progresses toward prostate cancer. In light of the significant sequelae of prostate cancer treatment, prevention is desirable, and men with HGPIN would be suitable, high-risk subjects. There is in vitro, in vivo, epidemiologic, and human experimental evidence that selenium supplementation may protect against prostate cancer. This article introduces the rationale for, and progress to date, of a double-blind, randomized, placebo-controlled trial of selenium supplementation (200 μg/d in the form of selenomethionine), to prevent the development of prostate cancer among men with HGPIN. The trial, Southwest Oncology Group Protocol 9917, funded by a National Cancer Institute program supporting pivotal prevention trials has registered 537 patients and has randomized >380 to date. Subject accrual is expected to be completed by the fall of 2006, with trial completion in 2009. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1479–84)
Associations among Mammographic Density, Circulating Sex Hormones, and Polymorphisms in Sex Hormone Metabolism Genes in Postmenopausal Women
Authors: Warren Ruth , Skinner Jane , Sala Evis , Denton Erika , Dowsett Mitch , Folkerd Elizabeth , Healey Catherine S. , Dunning Alison , Doody Deborah , Ponder Bruce , Luben Robert N. , Day N.E. , Easton Douglas
Published: August 2006

Mammographic density and serum sex hormone levels are important risk factors for breast cancer, but their associations with one another are unclear. We studied these phenotypes, together with single nucleotide polymorphisms (SNP) in genes related to sex hormone metabolism, in a cross-sectional study of 1,413 postmenopausal women from the European Prospective Investigation into Cancer and Nutrition-Norfolk. All women were >1 year postmenopausal and had not taken hormone replacement therapy for >3 months before sampling. Serum levels of 7 sex hormones [estradiol, testosterone, sex hormone-binding globulin (SHBG), androstenedione, 17-OH-progesterone, estrone, and estrone sulfate] and 15 SNPs in the CYP17, CYP19, EDH17B2, SHBG, COMT, and CYP1B1 genes were studied. Mammograms nearest in time to the blood sampling were identified through the national breast screening program and visually assessed by three radiologists using the Boyd six-category and Wolfe four-category scales. We found a weak positive association between mammographic density and SHBG levels (P = 0.09) but no association with any other hormones. None of the SNPs, including those shown previously to be associated with estradiol or SHBG, showed significant associations with density. We conclude that mammographic density is largely independent of postmenopausal steroid hormone levels, indicating that these risk factors have, to a large extent, an independent etiology and suggesting that they may be independent predictors of breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1502-08)
Chromosomal Instability in Barrett's Esophagus Is Related to Telomere Shortening
Authors: Finley Jennifer C. , Reid Brian J. , Odze Robert D. , Sanchez Carissa A. , Galipeau Patricia , Li Xiaohong , Self Steven G. , Gollahon Katherine A. , Blount Patricia L. , Rabinovitch Peter S.
Published: August 2006

Barrett's esophagus is a useful model for the study of carcinogenesis, as the metaplastic columnar epithelium that replaces squamous esophageal epithelium is at elevated risk for development of adenocarcinoma. We examined telomere length and chromosomal instability (CIN) in Barrett's esophagus biopsies using fluorescence in situ hybridization. To study CIN, we selected centromere and locus-specific arm probes to chromosomes 17/17p (p53), 11/11q (cyclin D1), and 9/9p (p16 INK4A), loci reported to be involved in early stages of Barrett's esophagus neoplasia. Telomere shortening was observed in Barrett's esophagus epithelium at all histologic grades, whereas CIN was highest in biopsies with dysplastic changes; there was, however, considerable heterogeneity between patients in each variable. Alterations on chromosome 17 were strongly correlated with telomere length (r = 0.55; P < 0.0001) and loss of the 17p arm signal was the most common event. CIN on chromosome 11 was also associated with telomere shortening (r =0.3; P = 0.05), although 11q arm gains were most common. On chromosome 9p, arm losses were the most common finding, but chromosome 9 CIN was not strongly correlated with telomere length. We conclude that CIN is related to telomere shortening in Barrett's esophagus but varies by chromosome. Whether instability is manifested as loss or gain seems to be influenced by the chromosomal loci involved. Because telomere shortening and CIN are early events in Barrett's esophagus neoplastic progression and are highly variable among patients, it will be important to determine whether they identify a subset of patients that is at risk for more rapid neoplastic evolution. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1451–7)
Flavonoids and Colorectal Cancer in Italy
Authors: Rossi Marta , Negri Eva , Talamini Renato , Bosetti Cristina , Parpinel Maria , Gnagnarella Patrizia , Franceschi Silvia , Dal Maso Luigino , Montella Maurizio , Giacosa Attilio , La Vecchia Carlo
Published: August 2006

Because of their several biological activities, flavonoids may have an important role in explaining the protective effects of vegetables, fruit, and, possibly, tea against cancer. The potential relation between flavonoids and colorectal cancer risk was investigated using data from a multicentric Italian case-control study, including 1,953 cases of colorectal cancers (1,225 colon cancers and 728 rectal cancers) and 4,154 hospital controls admitted for acute nonneoplastic diseases. We have applied recently published data on the composition of foods and beverages, in terms of six principal classes of flavonoids, on dietary information collected through a validated food-frequency questionnaire. Odds ratios (OR) were estimated by multiple logistic regression models, including terms for sex, age, study center, family history of colorectal cancer, education, alcohol consumption, body mass index, physical activity, and energy intake. A reduced risk of colorectal cancer was found for increasing intake of isoflavones (OR, 0.76, for the highest versus the lowest quintile, Ptrend = 0.001), anthocyanidins (OR, 0.67, Ptrend < 0.001), flavones (OR, 0.78, Ptrend = 0.004), and flavonols (OR, 0.64, Ptrend < 0.001). No significant association was found for flavan-3-ols (OR, 0.98), flavanones (OR, 0.96), and total flavonoids (OR, 0.97). The estimates did not substantially differ for colon and rectal cancers, as well as in strata of sex, age, and body mass index. The findings of this large study provide support for an inverse association of selected classes of flavonoids with colorectal cancer risk. (Cancer Epidemiol Biomarker Prev 2006;15(8):1555–8)
A Follow-up Study of Physical Activity and Incidence of Colorectal Polyps in African-American Women
Authors: Rosenberg Lynn , Boggs Deborah , Wise Lauren A. , Palmer Julie R. , Roltsch Mark H. , Makambi Kepher H. , Adams-Campbell Lucile L.
Published: August 2006

Background: Physical activity is associated with a reduced risk of colon cancer, but the effect of activity on colorectal adenomas, which are precursors to colon cancer, is uncertain. The influence of physical activity on colorectal adenomas among African-American women is of particular interest because African-American women have an increased risk of colon cancer relative to other U.S. women.

Methods: We prospectively assessed the relation of physical activity to the incidence of colorectal polyps among African-American women. We followed 45,400 women in the Black Women's Health Study from 1997 to 2003. Data were obtained by biennial mailed questionnaires. During 287,029 person-years of follow-up, 1,390 women reported having been diagnosed with colorectal polyps. A review of medical records of 58 women who reported colorectal polyps indicated that 59% had adenomas and 41% had hyperplastic polyps. We converted hours per week of vigorous exercise and hours per week of walking to metabolic equivalent (MET)-hours. We estimated incidence rate ratios with Cox proportional hazard models, controlling for age, body mass index, smoking, family history of colorectal cancer, and education.

Results: For total MET-hours/wk spent in walking and vigorous exercise, the incidence rate ratio decreased from 0.94 for <5 MET-hours/wk to 0.72 for ≥40 MET-hours/wk (Ptrend = 0.01). The inverse association was apparent among most subgroups examined, including women who may be at higher risk of colorectal adenomas because of being obese.

Conclusions: Increased physical activity is associated with a reduced incidence of colorectal polyps among African-American womend. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1438–42)
A Phase I Study of myo-Inositol for Lung Cancer Chemoprevention
Authors: Lam Stephen , McWilliams Annette , leRiche Jean , MacAulay Calum , Wattenberg Lee , Szabo Eva
Published: August 2006

Introduction: A phase I, open-label, multiple dose, dose-escalation clinical study was conducted to assess the safety, tolerability, maximum tolerated dose, and potential chemopreventive effect of myo-inositol in smokers with bronchial dysplasia.

Materials and Methods: Smokers between 40 and 74 years of age with ≥ 30 pack-years of smoking history and one or more sites of bronchial dysplasia were enrolled. A dose escalation study ranging from 12 to 30 g/d of myo-inositol for a month was first conducted in 16 subjects to determine the maximum tolerated dose. Ten new subjects were then enrolled to take the maximum tolerated dose for 3 months. The potential chemopreventive effect of myo-inositol was estimated by repeat autofluorescence bronchoscopy and biopsy.

Results: The maximum tolerated dose was found to be 18 g/d. Side effects, when present, were mild and mainly gastrointestinal in nature. Using the regression rate of the placebo subjects from a recently completed clinical trial with the same inclusion/exclusion criteria as a comparison, a significant increase in the rate of regression of preexisting dysplastic lesions was observed (91% versus 48%; P = 0.014). A statistically significant reduction in the systolic and diastolic blood pressures by an average of 10 mm Hg was observed after taking 18 g/d of myo-inositol for a month or more.

Conclusion: myo-Inositol in a daily dose of 18 g p.o. for 3 months is safe and well tolerated. The potential chemopreventive effect as well as other health benefits such as reduction in blood pressure should be investigated further. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1526–31)
Deletion Polymorphism of UDP-Glucuronosyltransferase 2B17 and Risk of Prostate Cancer in African American and Caucasian Men
Authors: Park Jong , Chen Lan , Ratnashinge Luke , Sellers Thomas A. , Tanner Jean-Paul , Lee Ji-Hyun , Dossett Nicole , Lang Nicholas , Kadlubar Fred F. , Ambrosone Christine B. , Zachariah Babu , Heysek Randy V. , Patterson Stephen , Pow-Sang Julio
Published: August 2006

Purpose: UDP-glucuronosyltransferases (UGT) are a family of enzymes that glucuronidate many endogenous chemicals, including androgens. This makes them more hydrophilic, alters biological activity, and facilitates their excretion. A deletion polymorphism in the UGT2B17 gene was recently described that was associated with a reduced rate of glucuronidation in vivo. The purpose of this study was to determine if the deletion polymorphism is associated with susceptibility to prostate cancer.

Materials and Methods: UGT2B17 expression was determined by reverse transcription-PCR of pathologically normal prostate tissues (n = 5). In a case-control study with 420 patients with incident primary prostate cancer (127 African Americans and 293 Caucasians) and 487 controls (120 African Americans and 367 Caucasians), the frequency of UGT2B17 deletion polymorphism in genomic DNA was compared between cases and controls with PCR analysis.

Results: UGT2B17 mRNA was detected only in individuals with at least one UGT2B17 allele. The frequency of the null genotype was present in 0.11 and 0.12 of Caucasian and African American controls, respectively. When all subjects were considered, a significant association was found between the UGT2B17 deletion polymorphism and prostate cancer risk [odds ratio (OR), 1.7; 95% confidence interval (95% CI), 1.2-2.6]. There was an increase in prostate cancer risk among individuals with UGT2B17 deletion polymorphism in Caucasians (OR, 1.9; 95% CI, 1.2-3.0) but not in African Americans (OR, 1.3; 95% CI, 0.6-2.7).

Conclusions: These results suggest that the UGT2B17 enzyme may play a role in the metabolism of androgens in prostate tissue and that the UGT2B17 deletion polymorphism is associated with prostate cancer risk. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1473–8)