bluuebunny/crossref_metadata_2025 huggingface dataset:
SOLUBILITY OF CARBON DIOXIDE IN FAT AND MUSCLE TISSUE
Authors: JAKOBSEN MARIANNE , BERTELSEN GRETE
Published: January 2006

When meat is packed in atmospheres containing elevated carbon dioxide (CO

2

) levels, substantial amounts of CO

2

are absorbed into the meat. Knowledge of CO

2

absorption into the meat is important to ensure optimal microbial protection of the meat and package design, preventing package collapse when the headspace is reduced because of CO

2

absorption. However, knowledge on fatty products is lacking. This study shows that there is a significant difference between the amounts of CO

2

that can be absorbed in meat with different fat content. The CO

2

absorption in fats has a rather complex temperature dependence that varies with fatty acid composition. The CO

2

absorption increases along with the increasing content of unsaturated fat, the effect growing larger as the temperature rises. In conclusion, the CO

2

solubility in meat samples varies with fat content, fatty acid composition as well as temperature. In this study CO

2

absorptions between 0.55 and 0.85 L CO

2

/kg meat were observed when varying these factors.
FERMENTATION AND CHEMICAL ACIDIFICATION OF SALAMI‐TYPE PRODUCTS – EFFECT ON YIELD, TEXTURE AND MICROSTRUCTURE
Authors: BARBUT S.
Published: January 2006

The effects of using lactic acid bacteria (LAB), liquid lactic acid and encapsulated acids (lactic, citric and glucono‐delta‐lactone [GDL]) to reduce the pH of salami‐type products were investigated. Liquid lactic acid caused an immediate pH drop, crumbling of meat particles and some moisture separation. This type of precooking protein denaturation resulted in the lowest springiness value and showed a microstructure with gaps among the cooked meat particles. The encapsulated acids did not produce such problems, and their effects on cook loss and hardness values varied. The nonacidified control (pH 5.60) provided the highest hardness value and low cook loss, because of less disruption to protein gelation during cooking. The slow acid release, during the overnight LAB fermentation, resulted in some binding prior to cooking, but a higher cook loss compared to the encapsulated acids.
USE OF HYDRODYNAMIC PRESSURE PROCESSING AND BLADE TENDERIZATION TO TENDERIZE TOP ROUNDS FROM BRAHMAN CATTLE†
Authors: LIU M.N. , SOLOMON M.B. , VINYARD B. , CALLAHAN J.A. , PATEL J.R. , WEST R.L. , CHASE C.C.
Published: January 2006

Tenderization effects of hydrodynamic pressure processing (HDP), blade tenderization (BT) and a combination of BT followed by HDP (BT + HDP) were evaluated with 12 top rounds from Brahman cattle selected for toughness. Warner–Bratzler shear testing was performed on the day of treatment (D0) and after storage (D7). On D0, BT and HDP increased tenderness by 18% and BT + HDP yielded a 14% improvement over control steaks. Tenderness increased (P < 0.05) for HDP and BT + HDP treatment between D0 and D7, whereas tenderness did not change for BT treatment. Control samples increased (P < 0.05) in tenderness because of aging alone (20% improvement). Overall tenderness improvements for BT + HDP and HDP (D7) versus control (D0) were 37 and 29%, respectively. BT provided instant tenderization but without additional improvement during aging. HDP and BT + HDP resulted in instantaneous tenderization that also increased over time and provided the greatest amount of overall improvement in tenderness.
Spatial Variation in Nitrogen Isotope Values Beneath Nitrate Contamination Sources
Authors: Fogg Graham E. , Rolston D.E. , Decker D.L. , Louie D.T. , Grismer M.E.
Published: January 2006

Nitrogen isotope ratios of soil water and ground water nitrate have been used to identify or implicate sources; however, lack of data on δ15N in thick (>12 m) vadose zones beneath the source and potential effects of denitrification on δ15N signatures have raised questions about the meaning of δ15N values measured in ground water. In this study, nitrogen isotope ratios (δ15N) were measured on nitrate extracted from 218 core samples removed from the surface to the water table below natural (soil organic matter) fertilizer, onsite sewage disposal systems (septic tank effluent), and animal sources located in Salinas and Sacramento Valleys, California. Additionally, spatial variability of δ15N in the horizontal plane was measured beneath an agricultural field, and δ15N values of native geologic materials (organic‐rich shales) were determined. In general, δ15N values throughout the vadose zone were consistent with the literature and remained fairly constant with depth, indicating little denitrification during transport. The δ15N values from soil organic matter sources varied from about 0 to +4‰, and the mean was not significantly different from that of fertilizer sources. The δ15N values of animal sources varied from about +8 to +20‰ and were dependent on site and animal source. The δ15N of onsite sewage disposal sources varied from about +2 to +12‰, and the mean was significantly different from that of animal sources at a 90% confidence level. δ15N of organic‐rich shales of the Panoche and Moreno Formations (Cretaceous; San Joaquin Valley) and soils derived from these rocks were generally between +4 and +8‰. Thus, it may be difficult to distinguish a geologic‐N source from septic tank or commercial fertilizer sources using δ15N. Little spatial variation was found in δ15N beneath the agricultural field in the horizontal plane.
Pumping Test Analysis for a Tidally Forced Aquifer
Authors: Trefry Michael G. , Johnston Colin D.
Published: January 2006

The analysis of pumping test data for a shallow riverbank aquifer afforded the opportunity to compare standard methods for determining hydraulic conductivity (K) and storativity (S) with techniques based on the propagation of periodic fluctuations of head in the aquifer. Tidal fluctuations in water level at the riverbank were found to propagate approximately nondispersively for 200 m in the aquifer, allowing tidal phase lags and amplitude attenuations in the aquifer to be estimated from river levels by least‐squares techniques. The least‐squares attenuations and phases were used to correct measured pumping test drawdowns for tidal influences. Standard transient analyses of the corrected drawdowns were performed, yielding values of approximately 8 to 10 m/d for K and 0.002 for S. The low S value was taken to indicate semi‐confined conditions. The tidal attenuation coefficients were used to determine the hydraulic diffusivity T/S, providing values that were integrated over the distance from the riverbank to the relevant monitoring wells. S values from the drawdown analyses then yielded K estimates ranging from 3 to 7 m/d. A three‐dimensional finite‐element simulation of the pumping tests showed that the estimated K and S values yielded simulated drawdowns in reasonable agreement with field observations.
The Effects of Pore Pressure on the Conductivity of Fractured Aquifers
Authors: Reichard James S. , Leap Darrell I.
Published: January 2006

In this study, we investigate the degree to which climate‐induced changes in hydraulic head can affect the stress regime and hydraulic conductivity of fractured aquifers. The effects of stress changes on conductivity are well‐known, but not usually considered in the analysis of ground water systems because of the misconception that the head change necessary to make a measurable impact is beyond the range of normal head fluctuations.

An empirical model relating changes in hydraulic conductivity of fractured aquifers to vertical‐effective stress was used in analyzing the effects of pore pressure changes on conductivity. An analysis showed that for realistic head changes (20 to 100 m), conductivity in an unconfined system can change as much as 20 to 30%. The analysis also showed that for a given head increase, increases in conductivity are greatest at shallow depths and that conductivity is a function of both hydraulic head and the relative position of head to the land surface. Maximum conductivity changes occur when the initial pore pressure is a relatively large percentage of the total stress. Similar results were also obtained in confined systems.

Field examples demonstrate that large head changes have occurred in bedrock aquifers due to climatic changes and pumping withdrawals. Thus, large head changes needed to make a measurable impact on hydraulic conductivity are quite plausible. Conductivity changes can in turn lead to changes in calculated ground water flow and solute transport rates. As a result, when significant head changes are expected, changes in conductivity should be considered in the analysis of fractured aquifer systems.
Air Permeability of Porous Materials Under Controlled Laboratory Conditions
Authors: Springer David S. , Loaiciga Hugo A. , Cullen Stephen J. , Everett Lome G.
Published: January 2006

A series of air permeability tests were conducted on four hand‐packed samples of alluvial sands and glass beads using a newly developed air permeameter. The permeameter was tested and found capable of precisely controlling soil‐water matric potential (in the range 0 to 1 bar) while simultaneously facilitating the direct measurement of air permeability in porous media. Permeameter results indicate that air permeability increases with a corresponding decrease in water content over a monotonic drainage cycle. It was observed that the rate of change in air permeability with respect to changes in water content is highest at high water content and lowest at low water content. In several soil samples, the air permeability approached a constant value at low water content. Air permeability variations with water content were observed to differ among soils of different texture. For example, the intrinsic permeability of water was 11 to 86% of the maximum air permeability. The new permeameter allowed rapid and accurate measurements of air permeability in fine‐textured materials over a wide range of matric potentials and water content.
Direct Simulation of Ground Water Age in the Rabis Creek Aquifer, Denmark
Authors: Engesgaard Peter , Molson John
Published: January 2006

The steady‐state ground water age distribution in the Rabis Creek Aquifer in Denmark is simulated directly and compared to the age estimated from observed tritium concentrations at three wells. The simulation code is based on an existing solute transport code, modified to include a zero‐order rate term of unity to account for the aging of ground water by one day per one day elapsed. The directly simulated ages of the observed tritium peaks agree to within less than four years with the observations. The tritium peaks would have been located to within 2 m vertically if the directly simulated ages had been used to select sampling depths in the three wells. An analytical solution that assumes that the geology is uniform and rectangular is shown to be a useful tool as a firsthand estimate of the age distribution. However, ages from a numerical direct age simulation that account for nonuniform aquifer properties agree better with the observed ages.
DNAPL Migration Through a Fractured Perching Layer
Authors: Stephens Daniel B. , Kelsey James A. , Prieksat Mark A. , Piepho Mel G. , Shan Chao , Ankeny Mark D.
Published: January 2006

The migration of a DNAPL (TCA) was demonstrated by a laboratory flow visualization experiment. The system consists of two unconfined aquifers separated by a siltstone perching layer containing a single fracture that conducts water flow downward. The TCA migrated along a tortuous path in the upper sandy aquifer and moved rapidly through the fracture. We observed no DNAPL pooling above the fracture prior to its entry into the fracture, in contrast to existing mathematical solutions of hydrostatic initial conditions and full saturation below the fracture. A multiphase flow model predicted the experimentally observed mean behavior.
Characterizing a Ground Water Basin in a New England Mountain and Valley Terrain
Authors: Tiedeman Claire R. , Goode Daniel J. , Hsieh Paul A.
Published: January 2006

A ground water basin is defined as the volume of subsurface through which ground water flows from the water table to a specified discharge location. Delineating the topographically defined surface water basin and extending it vertically downward does not always define the ground water basin. Instead, a ground water basin is more appropriately delineated by tracking ground water flowpaths with a calibrated, three‐dimensional ground water flow model. To determine hydrologic and chemical budgets of the basin, it is also necessary to quantify flow through each hydrogeologic unit in the basin. In particular, partitioning ground water flow through unconsolidated deposits versus bedrock is of significant interest to hillslope hydrologic studies. To address these issues, a model is developed and calibrated to simulate ground water flow through glacial deposits and fractured crystalline bedrock in the vicinity of Mirror Lake, New Hampshire. Tracking of ground water flowpaths suggests that Mirror Lake and its inlet streams drain a ground water recharge area that is about 1.5 times the area of the surface water basin. Calculation of the ground water budget suggests that, of the recharge that enters the Mirror Lake ground water basin, about 40% travels through the basin along flowpaths that stay exclusively in the glacial deposits, and about 60% travels along flowpaths that involve movement in bedrock.
Hydrogeochemical Processes and Fades in Confining Units of the Atlantic Coastal Plain in New Jersey
Authors: Pucci Amleto A.
Published: January 2006

Pore water solutes and sediments in the New Jersey Coastal Plain were studied to assess processes that control pore water chemistry in confining units and interactions with aquifer water chemistry. Solute chemistry and variations with depth are reported for 19 samples collected from a continuously cored borehole in the lower Miocene Kirkwood Formation at Atlantic City, New Jersey. In 14 pore water samples collected from the Lower Confining Unit overlying the Atlantic City 800‐foot Sand, and from the silt interbeds in the Upper Part of the Atlantic City 800‐foot Sand, linear regressions showed especially high correlations (R20.89) between concentrations of Mg and Ca; between concentrations of Na and the sum of Ca and Mg; between concentrations of SO4 and the sum of Ca and Mg; and between concentrations of Na and SO4. There were three distinct water quality types: Ca‐SO4, Ca‐Na‐SO4‐Cl‐HCO3, and Na‐SO4‐HCO3‐Cl. Each water type generally is within distinct intervals (tens of meters), or hydrogeochemical facies, in the core. The first two facies were found only in the units overlying the Atlantic City 800‐foot Sand; the third type was found only in samples from the underlying composite confining unit. Significant variation of pore water solute concentrations was indicated on a scale smaller than the sampling interval (about 3.5 m). Two principal components explained 82.5% of the total variation in pore water chemistry. The processes which control the variation in water quality include (1) chemical processes such as shell dissolution, incongruent carbonate dissolution, and clay transformations; (2) a hypothesized physical‐chemical mechanism of differential migration of sulfate accompanied by divalent cations; and (3) fresh water flushing of, and mixing with, residual sea water at paleoflow rates. Cation‐exchange reactions do not appear to be an important process in these sediments.
Characterizing Three‐Dimensional Hydraulic Conductivity Distributions Using Qualitative and Quantitative Geologic Borehole Data: Application to a Field Site
Authors: Zhang Zhihui , Brusseau Mark L.
Published: January 2006

The focus of this paper is the characterization of three‐dimensional hydraulic conductivity distributions using qualitative and quantitative geologic borehole data. We illustrate an approach that entails a three‐step procedure, where lithologic information reported in the borehole logs is first classified into texture classes. Representative hydraulic conductivity values are then calculated for each texture class using a correlation relating measured lithologic and hydraulic data from core samples. The generalized kernel estimator method, which can take full advantage of the characteristics of borehole log data and is applicable to statistically nonstationary systems, is used thereafter to generate the three‐dimensional distributions of hydraulic conductivity. An application using borehole data from a trichloroethene (TCE)‐contaminated Superfund site in Tucson, Arizona, is presented and used to test the proposed methodology. The simulated hydraulic conductivity distributions appear reasonable and the simulated permeability distributions for several cross sections agree well with the hydrogeologic cross‐sectional maps. The use of mean permeability indicators for differentiating zones of high and low permeability is also investigated.
Uncertainty Analyses of Fuel Hydrocarbon Biodegradation Signatures in Ground Water by Probabilistic Modeling
Authors: McNab Walt W. , Dooher Brendan P.
Published: January 2006

Natural attenuation processes, such as biodegradation, may serve as a means for remediating ground water contaminated by fuel hydrocarbons from leaking underground fuel tanks (LUFTs). Quantification of the uncertainties associated with natural attenuation, and hence the capacity to limit plume migration and restore an aquifer, is important. In this study, a probabilistic screening model is developed to quantify uncertainties involved in the impact of biodegradation on hydrocarbon plume behavior. The approach is based on Monte Carlo simulation using an analytical solution to the advective‐dispersive solute transport equation, including a first‐order degradation term, coupled with mass balance constraints on electron acceptor use. Empirical probability distributions for governing parameters are provided as input to the model. Application of the model to an existing LUFT site illustrates the degree of uncertainty associated with model‐predicted hydrocarbon concentrations and geochemical indicators at individual site monitoring wells as well as the roles of various parameter assumptions (e.g., hydraulic conductivity, first‐order decay coefficient, source term) in influencing forecasts. This information is useful for risk management planning because the degree of confidence that biodegradation will limit the impact of a hydrocarbon plume on potential receptors can be quantified.
Exercise associated hyponatraemia: quantitative analysis to understand the aetiology
Authors: Montain S J , Cheuvront S N , Sawka M N
Published: January 2006

Background:The development of symptomatic hyponatraemia consequent on participation in marathon and ultraendurance races has led to questions about its aetiology and prevention.

Objectives:To evaluate: (a) the assertion that sweat sodium losses cannot contribute to the development of hyponatraemia during endurance exercise; (b) the adequacy of fluid replacement recommendations issued by the International Marathon Medical Directors Association (IMMDA) for races of 42 km or longer; (c) the effectiveness of commercial sports drinks, compared with water, for attenuating plasma sodium reductions.

Methods:A mathematical model was used to predict the effects of different drinking behaviours on hydration status and plasma sodium concentration when body mass, body composition, running speed, weather conditions, and sweat sodium concentration were systematically varied.

Results:Fluid intake at rates that exceed sweating rate is predicted to be the primary cause of hyponatraemia. However, the model predicts that runners secreting relatively salty sweat can finish ultraendurance exercise both dehydrated and hyponatraemic. Electrolyte-containing beverages are predicted to delay the development of hyponatraemia. The predictions suggest that the IMMDA fluid intake recommendations adequately sustain hydration over the 42 km distance if qualifiers—for example, running pace, body size—are followed.

Conclusions:Actions to prevent hyponatraemia should focus on minimising overdrinking relative to sweating rate and attenuating salt depletion in those who excrete salty sweat. This simulation demonstrates the complexity of defining fluid and electrolyte consumption rates during athletic competition.
Serum concentrations of C reactive protein, α1antitrypsin, and complement (C3, C4, C1 esterase inhibitor) before and during the Vuelta a Espańa
Authors: Semple S J , Smith L L , McKune A J , Hoyos J , Mokgethwa B , San Juan A F , Lucia A , Wadee A A
Published: January 2006

Objectives:To determine serum concentrations of proinflammatory (C reactive protein, complement C3 and C4) and anti-inflammatory (α1antitrypsin, C1 esterase inhibitor (C1-INH)) acute phase proteins in elite cyclists before and during a three week cycle tour.

Methods:Seventeen professional cyclists participating in the Vuelta a Espańa volunteered for the study. Their mean (SD) physical characteristics were: age 28 (1) years; height 1.7 (0.06) m; weight 65 (7) kg; body fat 7.6 (0.8)%; Vo2max75.3 (2.3) ml/kg/min. Venepuncture was performed on each subject 24 hours before the tour began (T0), on day 11 (the first rest day; T1) and day 21 (the second to last stage of the tour; T2). Samples at T1 and T2 were taken about 17 hours after the previous stage. Analysis of variance was used to determine changes over time. Where significance was found, a Tukey post hoc test was performed.

Results:C reactive protein concentrations were consistently within the normal range, although there was a 228%, non-significant increase at T1. C3 concentrations fell within the normal range at all times assessed. C4 concentrations before the race were within the normal range and were significantly increased 10 days (T1) into the race. C1-INH concentrations did not change significantly throughout the race. α1Antitrypsin concentration before the race was at the lower end of the normal range and was only significantly raised at T2.

Conclusions:Although not as pronounced as those reported in marathon/ultramarathon runners, elite cyclists participating in a three week cycle tour experienced increases in selected proinflammatory and anti-inflammatory acute phase proteins, indicating an acute phase/inflammatory response. It is tenable that the increase in α1antitrypsin and C1-INH (anti-inflammatory mediators) at T2 served to attenuate the acute phase/inflammatory response. The lower than normal resting concentrations of the acute phase proteins supports the notion that chronic aerobic exercise induces an anti-inflammatory state.
Quantifying the functional rehabilitation of injured football players
Authors: Fuller C W , Walker J
Published: January 2006

Objective:To determine whether quantified, auditable records of functional rehabilitation can be generated using subjective assessments of players’ performance in fitness tests routinely used in professional football.

Method:Ten sequential test elements grouped into three phases (fitness, ball and match skills, match pace football) were used to monitor players’ functional recovery from injury. Physiotherapists subjectively assessed players’ performance in each test element using a six point subjective rating scale. Satisfactory performance in each element of the assessment programme added 10% to the injured player’s recovery score. Daily recovery scores for injured players were recorded against the time spent in functional rehabilitation.

Results:Rehabilitation data for 118 injuries sustained by 55 players over two seasons were recorded. The average time in functional rehabilitation depended on the time spent in pre-functional rehabilitation and the nature and location of injury. Benchmark functional rehabilitation curves (y  =  mln(x) + c) were developed for thigh (n  =  15) and lower leg (n  =  8) muscle strains and knee (n  =  7) and ankle (n  =  9) ligament sprains (R2 =  0.95–0.98).

Conclusions:A structured, quantified rehabilitation programme based on routine fitness and skills exercises and a graded subjective assessment of performance provides an auditable record of a player’s functional recovery from a range of lower limb injuries and a transparent exit point from rehabilitation. The proposed method provides a permanent record of the functional rehabilitation of players’ injuries and evidence based data to support management’s return to play decisions.
Concussive head injury in children and adolescents related to sports and other leisure physical activities
Authors: Browne G J , Lam L T
Published: January 2006

Objective:To compare the characteristics of children and adolescents with concussive head injury (CHI) sustained during organised sports or other leisure physical activity.

Methods:This was a case series study reviewing the medical records retrospectively over a four year period of children 6–16 years presenting to the emergency department with a CHI after participating in sport and/or recreation activity.

Results:There were 592 cases of sport and recreation related concussion over the study period (2000–2003). Most of the patients (n  =  424, 71.6%) were male, with half (n  =  304, 51.4%) being older than 10 years of age. A total of 152 (25.7%) cases of CHI were related to playing sports. Most cases (71.2%) were mild concussion. The cause of injury was a fall (n  =  322, 54.4%) or a collision. Nearly a quarter of the children (n  =  143, 24.2%) were admitted to hospital, with imaging performed in 134 (22.7%). Most children were treated appropriately and no adverse events were reported.

Conclusions:A severe CHI in a child is six times more likely to have resulted from organised sport than from other leisure physical activities. Outcomes for CHI in children is excellent, although their management places a considerable burden on emergency services. The need for activity restriction and the benefits of this in reducing long term cognitive effects of CHI are uncertain.
Biomass and root production of two plant life forms in a semiarid Mexican scrub: responses to soil nitrogen availability
Authors: Pavón Numa P.
Published: January 2006

The contribution of cacti and shrubs to root biomass and fine-root production was described in a semiarid Mexican scrub. Both life forms were evaluated for fine-root production variation in relation to changes of nitrogen in the soil, with a fertilization experiment. Cacti represented 78% of the total mean root biomass (660 ± 70 g·m–2(mean ± SE)) in the complete soil profile (50 cm in depth). In both life forms, root biomass was higher near the surface of the soil. Roots <3 mm in diameter represented 92.5% for cactus root biomass and 69.4% for shrubs. Monthly root biomass varied significantly between months, and significant differences were obtained between plant life forms. Fine and very fine root production was estimated as 3.76 Mg·ha–1·year–1, and cactus contribution to total root production was 81.2%. Significant differences were obtained between life forms. It was clear that a low concentration in the soil nitrogen diminishes fine-root production, supporting the hypothesis that in arid ecosystems nitrogen is a limiting factor for primary production.
Reexamination of a primitive ornithomimosaur, Garudimimus brevipes Barsbold, 1981 (Dinosauria: Theropoda), from the Late Cretaceous of Mongolia
Authors: Kobayashi Yoshitsugu , Barsbold Rinchen
Published: January 2006

The holotype of Garudimimus brevipes, discovered from the Upper Cretaceous sediments of Mongolia and named by Barsbold in 1981, is redescribed in detail in this paper. Reexamination of the holotype reveals a great deal of anatomical information, which allows us to revise the original diagnosis of this taxon and make comparisons with other ornithomimosaur taxa to understand the evolution of ornithomimosaurs. This paper suggests that characters used to differentiate this taxon in the original paper (short ilia, short metatarsals, exposure of the proximal end of metatarsal III, presence of pedal digit I, and absence of pleurocoels) are not apomorphies but represent the primitive conditions in ornithomimosaurs and are symplesiomorphies. Revised diagnoses are assigned for G. brevipes (posteriorly positioned jaw articulation, fossae at base of dorsal process of supraoccipital, paired depressions on neural spines of proximal caudal vertebra, and deep groove on lateral surface of pedal phalanges III-1 and III-2). Metatarsals of Garudimimus display a non-arctometatarsalian condition as in an Early Cretaceous form, Harpymimus, but the constriction of metatarsal III in Garudimimus is intermediate between Harpymimus and the arctometatarsalian condition in Gallimimus and other derived ornithomimosaurs (ornithomimids). Garudimimus is the only non-ornithomimid ornithomimosaur with edentulous jaws, which were probably covered by rhamphothecae. The loss of teeth with evolution of rhamphothecae and development of a cutting edge in the dentary of Garudimimus suggest the acquisition of feeding habits that included plucking food at the anterior portion of the jaw and cutting at the middle portion, similar to ornithomimids.
Structural testing of tectonic hypotheses by field-based analysis of distributed tangential shear: examples from major high-strain zones in the Grenville Province and other parts of the southern Canadian Shield
Authors: Schwerdtner W M , Riller U P , Borowik A
Published: January 2006

The Grenville Province and other parts of the Canadian Shield contain major (>100 km long) high-strain zones, also called shear belts or ductile shear zones, that are hosted by heterogeneously deformed gneisses and schists. In well-exposed segments of three nontabular zones whose dip angle is known locally, at the erosion level and (or) in the shallow subsurface, we investigate the tangential shear strain (better called the tangential unit shear or TUS) without assuming that mineral-shape lineations, common varieties of stretching lineations, are effectively parallel to the local TUS direction. Employing a graphic technique that copes with the geometric conditions of general triaxial strain, we approximate the actual direction and find the sense of local TUS in parts of (i) the Parry Sound shear zone, Grenville Province; (ii) the South Range shear zone, Southern Province; and (iii) the Uchi  English River subprovince boundary zone, Superior Province. Information thus obtained for individual high-strain zones in Ontario confirms the validity of published hypotheses: (i) 1020970 Ma, normal-sense distributed shearing in the Grenvillian thrust stack; (ii) northwest- directed thrusting of Huronian rocks over Archean basement; and (iii) north-directed thrusting of English River metasediments and associated migmatites onto the Uchi granitegreenstone terrain, under peak metamorphic conditions.
A comparison of Eastern North America and Coastal New England magma suites: implications for subcontinental mantle evolution and the broad-terrane hypothesis
Authors: Dorais Michael J , Harper Matthew , Larson Susan , Nugroho Hendro , Richardson Paul , Roosmawati Nova
Published: January 2006

New England and Maritime Canada host two major suites of Mesozoic diabase dykes. The oldest is the Coastal New England dykes that were emplaced between 225 and 230 Ma. These rocks are dominantly alkaline with trace element and isotopic compositions indicative of a high-238U/204Pb mantle (HIMU) source. The oldest of the ~200 Ma Mesozoic rift magmas is represented by the Talcott basalt of the Hartford basin and its feeder dykes. External to the basin is the compositionally equivalent Higganum dyke. The extension of the Higganum, the Onway dyke in New Hampshire, is identical in major and trace element and isotopic compositions indicating that the dyke system represented a feeder to flows of flood basalt proportions. The Talcott system rocks have some trace element similarities with arc basalts and have been interpreted as representing melts of a subduction zone modified mantle beneath the Laurentian- Gondwanan suture. Incompatible trace element ratios and Ba, Th, and U values are, however, unlike arc basalts and are more indicative of crustal contamination of the primary magma. The coastal New England magmas have oceanic island basalt signatures that are generally thought to represent plume-tail magmatism, which is antithetic to a plume-head origin for the younger eastern North America magmas. However, coastal New England rocks have the same trace element signatures as the alkaline rocks of the Loihi seamount, which represent the pre-shield stage to the voluminous tholeiitic magmatism in Hawaii.
Polymetamorphism of marbles in the Morin terrane, Grenville Province, Quebec
Authors: Peck William H , DeAngelis Michael T , Meredith Michael T , Morin Etienne
Published: January 2006

The Morin terrane (Grenville Province, Quebec) is dominated by the 1.15 Ga Morin Anorthosite Massif and related granitic intrusions, all of which exhibit granulite-facies mineral assemblages. Anorthosite-suite rocks are deformed both in shear zones and in the interior of the terrane and show intrusive contact relations with marble along road cuts near the village of St. Jovite. Intrusive rocks exposed in these road cuts have well-developed skarns, which were deformed with the intrusions after emplacement. Skarn minerals are consumed by garnet-forming reactions (e.g., An + Wo = Gr + Qtz) that preserve granulite-facies temperatures and pressures. Calcitegraphite thermometry of Morin terrane marbles records temperatures of 755 ± 38 °C (n = 21), independent of proximity to anorthosite-suite plutons. Preserved metamorphic conditions and the retrograde pressuretemperature (PT) path in the Morin terrane are very similar to conditions during the 1.07 Ga Ottawan orogeny in the Adirondack Highlands. Metamorphism and deformation of anorthosite-suite rocks and marbles of the Morin terrane are consistent with anorthosite intrusion followed by a distinct granulite-facies overprint.
Cordierite-gedrite rocks from the Central Metasedimentary Belt boundary thrust zone (Grenville Province, Ontario): Mesoproterozoic metavolcanic rocks with affinities to the Composite Arc Belt
Authors: Peck William H , Smith Michael S
Published: January 2006

Cordieritegedrite rocks in the southern Grenville Province occur near the base of the Central Metasedimentary Belt boundary thrust zone, interpreted by some as a crustal suture between the 1.291.24 Ga Composite Arc Belt and >1.4 Ga rocks of Laurentia. Major and trace-element compositions of these rocks are consistent with volcanic protoliths that range in composition from basalt to dacite. These cordieritegedrite rocks have low CaO (average 1.2 wt.%) and major element and oxygen-isotope ratios suggestive of hydrothermal alteration before metamorphism. Rare-earth element (REE) compositions also indicate igneous protoliths, although some REE patterns have been modified by local melt extraction. The trace-element compositions of cordieritegedrite rocks, and neodymium-isotope systematics, are similar to those of metavolcanic rocks in the Composite Arc Belt and are consistent with the extension of the Composite Arc Belt to the base of the boundary thrust zone.
Rediscovery of the Mattawa Anorthosite Massif, Grenville Province, Quebec
Authors: Owens Brent E , Dymek Robert F
Published: January 2006

We present new field observations and laboratory data confirming the presence of the Mattawa Anorthosite Massif (MAT), whose existence in south-central Quebec was hinted at more than 35 years ago. MAT thus represents a newly recognized member of the late- to post-tectonic ~10601010 Ma andesine anorthosite belt that includes the Château-Richer, St. Urbain, and Labrieville massifs. The dominant rock type at MAT is foliated andesine anorthosite or leuconorite, and orientations of foliations indicate that the pluton has the shape of a dome. MAT contains separate core and border zones, which are distinguished on the basis of plagioclase composition and concentrations of Ga, Rb, Sr, and Ba. Xenoliths of labradorite anorthosite having Ga, Sr, and Ba concentrations different from those of the host andesine anorthosites occur sporadically throughout the pluton as well. Lastly, rocks enriched in Fe, Ti, and P (jotunite, oxideapatite gabbronorite, nelsonite, ilmenitite) also occur at MAT, primarily near the coreborder transition or at the pluton margins. Compared with other anorthosites in the andesine belt, MAT is compositionally most similar to Labrieville. By analogy with Labrieville, we interpret the concentric zoning of MAT (more sodic core, more calcic border) to reflect polybaric crystallization accompanying upward intrusion as a magmatic diapir, which also produced the overall domal structure. The labradorite xenoliths bear little physical or compositional resemblance to typical Lac St. Jean rocks. Therefore, if the xenoliths were derived from the Lac St. Jean Anorthosite, their present character must reflect considerable modification by the Mattawa magma.
The Edison magnetite deposits in the context of pre-, syn-, and post-orogenic metallogenesis in the Grenville Highlands of New Jersey
Authors: Puffer J H , Gorring M L
Published: January 2006

Most of the magnetite deposits of the eastern Grenville Province have been described as precipitates from hydrothermal solutions derived from metamorphic processes, from early, late, or post-Grenville granites, or as metasediments. Granites host many of these deposits, but others, including the historic Edison iron mines of New Jersey, are hosted by potassium-feldspar gneiss, commonly interpreted as meta-arkose. Our new geochemical data indicate, however, that the protolith of the potassium-feldspar gneiss is rhyolite, not arkose. Supporting evidence includes (i) the absence of an underlying potassic provenance for arkosic sediment, (ii) potassium and sodium contents among host rocks that exceed the range of arkose but are consistent with A-type rhyolite, and (iii) a close chemical resemblance of the potassium-feldspar gneiss to an A-type granite (Byram granite) that is closely associated in time and space. As the ore zone through the Edison mines is approached, the K/Na ratio of the host rocks undergoes a distinct increase, consistent with extensive diagenetic alteration of rhyolitic pyroclastics in a hypersaline environment. This alteration provided a local ligand source for subsequent hydrothermal iron mineralization derived from the nearby pre-orogenic Byram granite. These iron concentrations were then remobilized and recrystallized during subsequent Grenville metamorphism. Although some of the magnetite deposits of the New Jersey Highlands display evidence of post-orogenic replacement and an association with undeformed pegmatites, the banded magnetite ore and related pegmatites of the Edison mines are conformable to the foliation of the host rock and are interpreted as metamorphic products of pre-orogenic, granite-derived, hydrothermal iron concentrates.
Mesoproterozoic deep K-magmatism recorded in a megacryst- and xenolith-bearing minette dyke, western Grenville Province
Authors: Morin David , Hébert Réjean , Corriveau Louise
Published: January 2006

The 1.07 Ga Rivard minette dyke transported thousands of exotic (xenoliths) and cogenetic (cognate nodules) clasts from deep lithospheric levels of the Grenville Province. Nodules related to the clinopyroxene- and biotite-phyric host consist of megacrystic clinopyroxene and K-feldspar and mica-rich pyroxenite. Clinopyroxene megacrysts record high-pressure and high-temperature crystallization, crystal recycling, or magma mixing, whereas Ba-rich K-feldspar megacryst possibly represent near-solidus phenocrysts crystallized from evolved K-rich magmas. Mica-pyroxenite xenoliths are interpreted as products of magma mixing or infiltration of K-rich melt in pyroxene cumulate. Partial replacement of pyroxenes by strained phlogopite attests to mica crystallization before or during plastic deformation and prior to xenolith incorporation in the minette. The minette is mafic, ultrapotassic, and enriched in large-ion lithophile elements and light rare-earth elements. It experienced limited fractionation and crustal contamination but has been exposed to magma mixing. High K, La, and Cr contents suggest partial melting of a K-metasomatized mantle source. The Rivard minette shares the age, mineralogy, and chemistry with the 1.091.07 Ga KensingtonSkootamatta potassic alkaline suite and forms part of a common K-rich magmatic event taking its source in an enriched mantle. Source heterogeneity, conditions of partial melting, crystal fractionation, magma mixing, and crustal contamination all contributed, to various extents, to the complex chemistry of the K-rich intrusions of the KensingtonSkootamatta suite. Collectively, this suite records extensive and diverse magmatic batches derived from partial melting of a mantle metasomatized during subduction events prior to emplacement.
Le magmatisme de la région de Kwyjibo, Province du Grenville (Canada) : intérêt pour les minéralisations de type fer-oxydes associées
Authors: Magrina Benoît , Jébrak Michel , Cuney Michel
Published: January 2006

The granitic plutons located north of the Kwyjibo property in Quebec's Grenville Province are of Mesoproterozoic age and belong to the granitic Canatiche Complex . The rocks in these plutons are calc-alkalic, K-rich, and meta- to peraluminous. They belong to the magnetite series and their trace element characteristics link them to intraplate granites. They were emplaced in an anorogenic, subvolcanic environment, but they subsequently underwent significant ductile deformation. The magnetite, copper, and fluorite showings on the Kwyjibo property are polyphased and premetamorphic; their formation began with the emplacement of hydraulic, magnetite-bearing breccias, followed by impregnations and veins of chalcopyrite, pyrite, and fluorite, and ended with a late phase of mineralization, during which uraninite, rare earths, and hematite were emplaced along brittle structures. The plutons belong to two families: biotite-amphibole granites and leucogranites. The biotite-amphibole granites are rich in iron and represent a potential heat and metal source for the first, iron oxide phase of mineralization. The leucogranites show a primary enrichment in REE (rare-earth elements), F, and U, carried mainly in Y-, U-, and REE-bearing niobotitanates. They are metamict and underwent a postmagmatic alteration that remobilized the uranium and the rare earths. The leucogranites could also be a source of rare earths and uranium for the latest mineralizing events.[Traduit par la Rédaction]
Introduction to the Grenville Province: a geological and mineral resources perspective derived from government and academic research initiatives
Authors: Corriveau Louise , Clark Thomas
Published: January 2006

Canadian society faces a significant decline in the number of active mines and in the discovery rate of base and precious metal deposits. Exploring in the shadows of active and former mines with improved metallogenic models and new technologies is one way to address this problem. Another way is to diversify mineral exploration outside known mining camps and target prospective but underexplored settings and nonconventional mineral deposits. In Canadian terms, diversifying exploration commonly translates into targeting gneissic and granitic terrains where modern geoscience knowledge may be rare or only at reconnaissance scale and where key regional and local indicators and vectors to ore may be missing in the geological record. Though underexplored settings abound in Canada, only one orogen has an aura that discourages exploration: the Grenville Province. Consequently, even though the Grenville Province provides the best model of a deep continental-collision zone so far studied anywhere on Earth and constitutes a microcosm of continental accretion, it remains underexplored, underprospected, undermapped and underestimated. It is thus essential to revisit the mineral potential of the most accessible orogen of the Canadian Shield, search for its missing volcanic belts, reexamine its ore deposits and mineral occurrences, and explore new research avenues using the best remote-sensing device on Earth: human eyes. This special issue captures advances associated with regional field investigations by government that played a special role in opening up frontier areas for mineral exploration. Papers stemming from academia and governmentuniversityindustry consortiums investigate further some of the topics covered by these and earlier surveys and others contribute structural and metamorphic insights that will be valuable in future mapping projects. The advances reported here for the Grenville Province may provide impetus to revisit other Grenville-age terrains worldwide, just as metallogenic models developed in other countries have provided the means to look in a different manner at the Grenville orogen for mineral deposits. Collectively all the various approaches presented in this volume help us to revamp our way of looking at the mineral potential of the Grenville orogen.
Elucidating patterns of size-dependent predation on larval yellow perch (Perca flavescens) in Lake Michigan: an experimental and modeling approach
Authors: Fulford Richard S , Rice James A , Miller Thomas J , Binkowski Fred P
Published: January 2006

Yellow perch (Perca flavescens) in Lake Michigan have experienced sustained recruitment failure since 1990 as a result of increased mortality during the pelagic larval phase. Increased mortality of larval yellow perch has been tied indirectly to increased alewife (Alosa pseudoharengus) predation, but effects of predation on larval survival variability must be better understood. We compared the relative importance of predation by alewife and two other fish predators to larval survival in laboratory experiments and developed an individual-based predation model (IBM) to examine patterns in size-dependent predation vulnerability. Simulations exposing larval perch to predation by all predators suggest that larval mortality resulting from alewife predation is more size-dependent than mortality resulting from the other two predators, and the range of sizes vulnerable to alewife is smaller. Alewife predation may not be an important mortality source for larval yellow perch in Lake Michigan at present because of the narrow range of vulnerable sizes and low densities of larval perch in the open lake. Predation is more likely to be important in smaller, more productive systems where other predators are abundant. Modeling results also indicate IBM analysis of date of hatch distributions of surviving larvae is a valuable tool for identifying factors most important to larval survival.
The logic of skipped spawning in fish
Authors: Jørgensen Christian , Ernande Bruno , Fiksen Øyvind , Dieckmann Ulf
Published: January 2006

That sexually mature fish skip reproduction, especially in response to poor condition, has been documented in many species. We present results from an energy-allocation life history model that shed light on the underlying logic of skipped spawning, based on the Northeast Arctic stock of Atlantic cod (Gadus morhua). The model predicts that skipped spawning is a regular phenomenon, with up to 30% of the sexually mature biomass skipping spawning. Spawning should be skipped if the expected future gain in reproductive output, discounted by survival, more than balances the expected reproductive success the current year. Skipped spawning was most common (i) among potential second-time spawners and (ii) early in life, (iii) when fishing mortality at the spawning grounds was high, (iv) when fishing mortality at the feeding grounds was low, (v) when natural mortality was low, and (vi) when the energetic and mortality costs associated with migration and spawning were high. Cod skipped spawning more often when food availability was both increased (opportunities for better growth) and decreased (too little energy for gonad development), and this pattern interacted with mortality rate. We conclude that skipped spawning may be more widespread than appreciated and highlight potential consequences for the understanding of stockrecruitment relationships.