bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of CTLA‐4 gene polymorphism with oral squamous cell carcinoma
Authors: Wong Y.‐K. , Chang K.‐W. , Cheng C.‐Y. , Liu C.‐J.
Published: January 2006

Background:  Oral squamous cell carcinoma (OSCC) is a worldwide problem. The main mechanism of tumor immunity is the destruction of tumor cells by cytolytic T lymphocytes. Cytotoxic T lymphocyte‐associated antigen 4 (CTLA‐4; CD152), a negative regulator of T‐lymphocyte activation, plays an extremely important role in the immune tolerance and anergy. This study was designed to investigate the role of CTLA‐4 polymorphism in OSCC.

Methods:  The CTLA‐4 +49 A/G polymorphism was studied in 118 patients with OSCC and 147 healthy controls by using restriction fragment length polymorphism (RFLP). The genotype and phenotype frequencies were evaluated in Fisher's exact test.

Results:  There was no significant difference in the frequency of CTLA‐4 polymorphism between the OSCC study group and healthy controls. The CTLA‐4 A/A genotype was significantly associated with a younger age of onset of OSCC (P = 0.04). The AA genotype was associated with significantly poorer survival (P = 0.003).

Conclusion:  The present study is the first to shows that the A/A polymorphism is associated with poor survival in OSCC in Taiwan.
The melanosomal/lysosomal protein OA1 has properties of a G protein‐coupled receptor
Authors: Innamorati Giulio , Piccirillo Rosanna , Bagnato Paola , Palmisano Ilaria , Schiaffino Maria Vittoria
Published: January 2006

The protein product of the ocular albinism type 1 gene, named OA1, is a pigment cell‐specific integral membrane glycoprotein, localized to melanosomes and lysosomes and possibly implicated in melanosome biogenesis. Although its function remains unknown, we previously showed that OA1 shares structural similarities with G protein‐coupled receptors (GPCRs). To ascertain the molecular function of OA1 and in particular its nature as a GPCR, we adopted a heterologous expression strategy commonly exploited to demonstrate GPCR‐mediated signaling in mammalian cells. Here we show that when expressed in COS7 cells OA1 displays a considerable and spontaneous capacity to activate heterotrimeric G proteins and the associated signaling cascade. In contrast, OA1 mutants carrying either a missense mutation or a small deletion in the third cytosolic loop lack this ability. Furthermore, OA1 is phosphorylated and interacts with arrestins, well‐established multifunctional adaptors of conformationally active GPCRs. In fact, OA1 colocalizes and coprecipitates with arrestins, which downregulate the signaling of OA1 by specifically reducing its expression levels. These findings indicate that heterologously expressed OA1 exhibits two fundamental properties of GPCRs, being capable to activate heterotrimeric G proteins and to functionally associate with arrestins, and provide proof of principle that OA1 can actually function as a canonical GPCR in mammalian cells.
Diversity of pigmentation in cultured human melanocytes is due to differences in the type as well as quantity of melanin
Authors: Wakamatsu Kazumasa , Kavanagh Renny , Kadekaro Ana L. , Terzieva Silva , Sturm Richard A. , Leachman Sancy , Abdel‐Malek Zalfa , Ito Shosuke
Published: January 2006

Cultured human melanocytes differ tremendously in visual pigmentation, and recapitulate the pigmentary phenotype of the donor's skin. This diversity arises from variation in type as well as quantity of melanin produced. Here, we measured contents of eumelanin (EM) and pheomelanin (PM) in 60 primary human melanocyte cultures (51 neonatal and nine adults), and correlated some of these values with the respective activity and protein levels of tyrosinase, and the melanocortin‐1 receptor (MC1R) genotype. Melanocytes were classified into four phenotypes (L, L+, D, D+) as depicted by visual pigmentation using light microscopy, and by the pigmentary phenotype of the donor's skin. There were large differences in total melanin (TM) and EM, which increased progressively for L, L+, D and D+ melanocytes. TM content, the sum of EM and PM, showed a good correlation with TM measured spectrophotometrically, and with the activity and protein levels of tyrosinase. Log EM/PM ratio did not correlate with MC1R genotype. We conclude that: (i) EM consistently correlates with the visual phenotype; (ii) lighter melanocytes tend to be more pheomelanic in composition than darker melanocytes; (iii) in adult melanocyte cultures, EM correlates with the ethnic background of the donors (African‐American > Indian > Caucasian); and (iv) MC1R loss‐of‐function mutations do not necessarily alter the phenotype of cultured melanocytes.
Plasma melatonin and insulin‐like growth factor‐1 responses to dim light at night in dairy heifers
Authors: Muthuramalingam P. , Kennedy A. D. , Berry R. J.
Published: January 2006

Abstract:  The effect of dim (5, 10 and 50 1x) light at night on night plasma melatonin level (NML) and night plasma insulin‐like growth factor‐1 (IGF‐1) level was determined in 12 prepubertal Holstein heifers (245 ± 16 days age) using a 4 × 4 Latin Square design with 14‐day treatment and 14‐day recovery periods. Blood samples were collected at 23:00 hr (prior to the 8 hr night treatment which commenced at mid‐night) on days 0, 3 and 13, and throughout the night at 01:00, 02:00, 03:00, 04:00, 06:00 and 08:00 hr on days 1, 4 and 14 of treatment. Plasma was analysed by radioimmunoassay for melatonin (all samples) and IGF‐1 (samples for day 14, 04:00 hr only). Treatment (P = 0.03) and treatment × time (P = 0.02) were significant for NML. Exposure to 50 lx suppressed NML by 50% during the initial 2 hr of the night, but not thereafter. Exposure to 5 and 10 lx had no effect on NML. The NML response to 50 lx was found on all treatment days studied (treatment × time × day; P = 0.99). There was no treatment effect on plasma IGF‐1 level (P = 0.89), but plasma IGF‐1 level was higher (P = 0.001) during period 4. Plasma IGF‐1 level and NML tended (P = 0.10) to be negatively correlated. Light intensities of 10 lx or less appear safe for use at night in dairy barns where darkness is recommended.
Inhibitory effects of melatonin on the growth of pituitary prolactin‐secreting tumor in rats
Authors: Yang Quan‐Hui , Xu Jian‐Ning , Xu Rong‐Kun , Pang Shiu‐Fun
Published: January 2006

Abstract:  The in vivo effects of melatonin on proliferation and apoptosis of 17‐β‐estradiol (E2)‐induced pituitary prolactin‐secreting tumor (prolactinoma) were investigated in rats kept in 12 L/12 D (lights on: 06:00–18:00 hr). As melatonin was shown to induce apoptosis of breast and liver tumor cells, we examined whether melatonin would induce apoptosis of rat pituitary prolactinoma cells. 0.125, 0.25, 0.50 or 1.0 mg melatonin/day/rat was administrated subcutaneously at 17:30–18:00 hr. The weight of prolactinomas was measured. Apoptosis was evaluated using the TdT‐mediated dUTP nick‐end labeling method. It was found that treatment with 0.25 and 0.50 mg melatonin for 97 days inhibited prolactinoma cell proliferation and increased prolactinoma cell apoptosis. Furthermore, melatonin induced mRNA expression of Bax and cytochrome c protein expression. Conversely, mRNA expression of Bcl‐2, and mitochondrial membrane potential were inhibited by melatonin treatment. These results suggest that melatonin inhibits the proliferation and induces apoptosis of rat pituitary prolactin‐secreting tumor via perturbation of mitochondria physiology.
Comparison of the Performance of Varimax and Promax Rotations: Factor Structure Recovery for Dichotomous Items
Authors: Finch Holmes
Published: January 2006

Nonlinear factor analysis is a tool commonly used by measurement specialists to identify both the presence and nature of multidimensionality in a set of test items, an important issue given that standard Item Response Theory models assume a unidimensional latent structure. Results from most factor‐analytic algorithms include loading matrices, which are used to link items with factors. Interpretation of the loadings typically occurs after they have been rotated in order to amplify the presence of simple structure. The purpose of this simulation study is to compare the ability of two commonly used methods of rotation, Varimax and Promax, in terms of their ability to correctly link items to factors and to identify the presence of simple structure. Results suggest that the two approaches are equally able to recover the underlying factor structure, regardless of the correlations among the factors, though the oblique method is better able to identify the presence of a “simple structure.” These results suggest that for identifying which items are associated with which factors, either approach is effective, but that for identifying simple structure when it is present, the oblique method is preferable.
An Extension of Four IRT Linking Methods for Mixed‐Format Tests
Authors: Kim Seonghoon , Lee Won‐Chan
Published: January 2006

Under item response theory (IRT), linking proficiency scales from separate calibrations of multiple forms of a test to achieve a common scale is required in many applications. Four IRT linking methods including the mean/mean, mean/sigma, Haebara, and Stocking‐Lord methods have been presented for use with single‐format tests. This study extends the four linking methods to a mixture of unidimensional IRT models for mixed‐format tests. Each linking method extended is intended to handle mixed‐format tests using any mixture of the following five IRT models: the three‐parameter logistic, graded response, generalized partial credit, nominal response (NR), and multiple‐choice (MC) models. A simulation study is conducted to investigate the performance of the four linking methods extended to mixed‐format tests. Overall, the Haebara and Stocking‐Lord methods yield more accurate linking results than the mean/mean and mean/sigma methods. When the NR model or the MC model is used to analyze data from mixed‐format tests, limitations of the mean/mean, mean/sigma, and Stocking‐Lord methods are described.
LIPID ANALYSIS OF FILLETS FROM GIANT GRENADIER (ALBATROSSIA PECTORALIS), ARROW‐TOOTH FLOUNDER (ATHERESTHES STOMIAS), PACIFIC COD (GADUS MACROCEPHALUS) AND WALLEYE POLLOCK (THERAGRA CHALCOGRAMMA)
Authors: OLIVEIRA A.C.M. , BECHTEL P.J.
Published: January 2006

In Alaska, walleye pollock (WP [Theragra chalcogramma]) and Pacific cod (PC [Gadus macrocephalus]) are harvested in large amounts. There are also large biomasses of arrow‐tooth flounder (ATF [Atheresthes stomias]) and giant grenadier (GG [Albatrossia pectoralis]) available in Alaskan waters; however, these fish are underutilized. The objective of this study was to determine lipid content, lipid class distribution and fatty acid (FA) profiles of fillets from these four fish species. Fat content and percent triacylglycerides (TAG) in ATF was significantly higher than in other species, and percent phospholipids (PL) was lower (P < 0.05). PC had the highest levels of omega‐3 (ω‐3) FA, whereas ATF had the lowest. The ratio of ω‐3/omega‐6 (ω‐6) FA was significantly higher in ATF than in other species. Percent polyunsaturated and saturated FA's were equivalent in ATF; however, other species showed at least twice as much polyunsaturated FA as saturated FA. This study provided comparisons of the lipid characteristics in the two most abundant white fish harvested in Alaska and two other abundant but underutilized species.
THE EFFECT OF EPIMYSIAL CONNECTIVE TISSUE ON FACTORS RELATED TO TENDERNESS OF BEEF SEMITENDINOSUS
Authors: JANZ J.A.M. , AALHUS J.L. , PRICE M.A.
Published: January 2006

Previous investigations have revealed consistently unacceptable levels of toughness in beef semitendinosus (ST; eye of round). It is possible that the fusiform architecture of the ST permits moisture loss during cooking as the epimysial connective‐tissue (CT) layer shrinks with heating. This investigation of the effects of the presence/absence of the epimysium demonstrated significantly (P < 0.01) greater shear values in samples with an intact external CT layer. However, the reduction in shear with epimysium removal was small (4.45%) and would not have been sufficient to bring a large proportion of ST steaks into the range of acceptable eating quality. The ST is atypical of skeletal muscle with regards to its biomechanical function and native elastin content, and this possible contributor to toughness requires further investigation in order to develop a suitable method for tenderness improvement.
HYDRODYNAMIC PRESSURE‐PROCESSED BEEF SEMITENDINOSUS MUSCLE USING A STEEL REFLECTOR BOWL†
Authors: CALLAHAN JANICE A. , BERRY BRADFORD W. , SOLOMON MORSE B. , LIU MARTHA N.
Published: January 2006

Hydrodynamic pressure (HDP) technology, used to tenderize meat, has been previously conducted in both stationary steel hemisphere‐shaped tanks (1060‐L commercial and 54‐L laboratory scale steel units) as well as in plastic explosive containers (PEC) fitted with a flat metal reflector plate. It was hypothesized that the bottom surface of the container may affect the magnitude of tenderness improvement during the HDP process. A steel reflector bowl was constructed to fit inside the PEC to mimic the shape of the bottom of the stationary steel vessel. Beef semitendinosus (ST) muscles treated with HDP (150‐g binary explosive detonated inside a water‐filled 98‐L PEC) were more tender (P < 0.05) than controls (5.37 versus 5.74 kgf). ST response to HDP was highly variable (−8.6 to 24.5%). Although the improvement in ST tenderness was significant (P < 0.05), using the steel reflector bowl in the PEC was not an efficient method to tenderize ST muscles.
The Determination of Glacial Till Specific Storage in North Dakota
Authors: Shaver Robert B.
Published: January 2006

Specific storage (Ss) was calculated for 107 glacial till core samples collected in 1962 from 93 drilling sites at U.S. Air Force Intercontinental Ballistic Missile launch and launch control facilities located in North Dakota. Core sample depths ranged from 8 to 26 m. Consolidation tests were performed on the till samples using a floating ring consolidometer. The coefficient of volume change (mv), which is defined as the volume change per unit volume per unit increase in effective stress, was calculated for this study using previously reported consolidation test data. Ss calculated for the 107 till samples ranged from 2.0 × 10‐4m‐1 to 1.1 × 10‐3m‐1, with a mean value of 5.6 × 0‐4m‐1.

Till is easily compressible and, as a result, Ss is not constant, but rather a function of loading. With increased depth, effective stress (σ0) increases and Ss decreases. Based on data from 107 till cores in this study, the relationship between σ0 and Ss is described by: Ss= 0.049σ0−0.84, (r2= 0.60, p<0.0001), where σ0= in situ effective stress in kPa, and Ss= specific storage in m‐1.
Hydrogeologic Controls on Radon‐222 in a Buried Valley‐Fractured Bedrock Aquifer System
Authors: Veeger A.I. , Ruderman N.C.
Published: January 2006

A field study was conducted to evaluate the distribution of radon (222Rn) and the hydrogeologic controls on its occurrence in the glacial and fractured rock aquifers of the Pawcatuck River Basin, Rhode Island. A total of 91 ground water samples were collected and analyzed for major chemical constituents as well as uranium and 222Rn. The three bedrock types underlying the study area include the Proterozoic Esmond and Sterling gneisses, and the Devonian Scituate Granite, each having average uranium contents of 1.9 ppm, 3.3 ppm, and 4.1 ppm, respectively (Nevins 1991). All wells sampled in this study yielded radon levels above the proposed U.S. EPA limit of 300 pCi/L. Wells in areas underlain by the Esmond Suite had the lowest radon content (range 500 to 30,400 pCi/L, median 1400 pCi/L), areas underlain by the Sterling Suite were not significantly different but showed slightly higher concentrations (range 700 to 27,300 pCi/L, median 1600 pCi/L), and the areas underlain by the Scituate Suite had significantly higher levels (range 1600 to 83,500 pCi/L, median 5900 pCi/L). High fluoride and alkalinity concentrations in ground water were found to be hydrogeochemical markers for elevated radon concentrations. These markers are believed to represent chemical reactions that produce remobilization of uranium in the host crystalline rock to more favorable siting along grain and fracture boundaries. Physical characteristics such as porosity and the location of uranium are controlling factors in the distribution of radon between surficial and bedrock wells, with bedrock aquifers exhibiting higher radon concentrations than surficial‐materials aquifers in this basin.
Assignment of Boundary Conditions in Embedded Ground Water Flow Models
Authors: Leake S.A. , Lawson Peter W. , Lilly Michael R. , Claar David V.
Published: January 2006

Many small‐scale ground water models are too small to incorporate distant aquifer boundaries. If a larger‐scale model exists for the area of interest, flow and head values can be specified for boundaries in the smaller‐scale model using values from the larger‐scale model. Flow components along rows and columns of a large‐scale block‐centered finite‐difference model can be interpolated to compute horizontal flow across any segment of a perimeter of a small‐scale model. Head at cell centers of the larger‐scale model can be interpolated to compute head at points on a model perimeter. Simple linear interpolation is proposed for horizontal interpolation of horizontal‐flow components. Bilinear interpolation is proposed for horizontal interpolation of head values. The methods of interpolation provided satisfactory boundary conditions in tests using models of hypothetical aquifers.
Watershed Delineation and Ground Water Discharge to a Coastal Embayment
Authors: Cambareri Thomas C. , Eichner Eduard M.
Published: January 2006

Nonpoint source management strategies for watersheds to eutrophic coastal waters require an adequate characterization of subsurface hydrogeology to understand the sources and fate of ground water and contaminant flow. An investigation was conducted to define the watershed to Waquoit Bay, a shallow eutrophic coastal embayment at the margin of the sand and gravel aquifer of Cape Cod, Massachusetts. This investigation included: (1) the development of a subregional water table map over 56 square kilometers; (2) delineation of a watershed and subwatersheds by plotting reverse ground water flowpaths; (3) a water budget based on a mass balance between recharge rates over riverine watershed segments and measured stream flows; and (4) a series of well points driven beneath the bed of the embayment and a transect of deep geologic borings perpendicular to the shore to characterize submarine ground water and hydrogeologic conditions at depth. The principal aquifer thins from the apex of the watershed, where it is approximately 46 m thick, to approximately 11 m thick as it nears Waquoit Bay. The detailed water table map shows extremely high hydraulic gradients to the rivers and comparably smaller gradients near the bay, indicating the thinning aquifer forces ground water to discharge into the rivers and causes them to function as significant surface drains for the aquifer. A classic sharp salt water interface was found in the upper 11.3 m thick High K unit, while the interface in the lower 34 m thick Low K unit was estimated to extend 700 m from the shoreline beneath the saline water of the bay. Eighty‐nine percent (89%) of the bay water budget is from ground water flow (55% channeled into rivers and 34% direct ground water discharge), while 11% is from atmospheric deposition. The Low K unit is an insignificant source of fresh water to the embayment. The conceptual hydro‐geologic model of the watershed is consistent with the water table configuration and the mass balance water budget and was confirmed by subsurface characterization of the near shore hydrogeology. This type of watershed characterization provides a firm basis for the development of nonpoint source management options for coastal embayments.
A 3H/3He Study of Ground Water Flow in a Fractured Bedrock Aquifer
Authors: Aeschbach‐Hertig W. , Schlosser P. , Stute M. , Simpson H.J. , Ludin A. , Clark J.F.
Published: January 2006

The concentrations of tritium, helium isotopes, and neon have been measured in ground water from a fractured bedrock aquifer in a densely populated suburban area near New York City. Samples were obtained from heavily pumped production wells of a regional water supply company. Helium and neon concentrations exceed the values for air‐saturated water, which is explained by the addition of unfractionated atmospheric air, radiogenic helium, and tritiogenic 3He. The identification of the composition of these excess components allows reliable separation of the tritiogenic 3He concentration, and hence the calculation of the 3H/3He ages of the ground water. Comparison of the combined tritium plus tritiogenic 3He concentrations with the historical record of tritium input from precipitation confirms that the 3H/3He data are self‐consistent and provides constraints on the degree of mixing or helium loss. The distribution of 3H/3He ages is related to the large‐scale topography of the study area and the depth of the wells. Furthermore, correlations between the 3H/3He ages and concentrations of total dissolved solids and total CO2 show that the ages contain meaningful information related to the temporal changes of the ground water chemistry.
Adolescent flexibility, endurance strength, and physical activity as predictors of adult tension neck, low back pain, and knee injury: a 25 year follow up study
Authors: Mikkelsson L O , Nupponen H , Kaprio J , Kautiainen H , Mikkelsson M , Kujala U M
Published: January 2006

Objective:To examine whether adolescent flexibility, endurance strength, and physical activity can predict the later occurrence of recurrent low back pain, tension neck, or knee injury.

Methods:In 1976, 520 men and 605 women participated in a sit and reach test (flexibility) and a 30 second sit up test (endurance strength). In 1976 and 2001 (aged 37 and 42 years) they completed a questionnaire. Lifetime occurrence and risk of self reported low back pain and self reported, physician diagnosed tension neck and knee injury were calculated for subjects divided into tertiles by baseline results of strength and flexibility tests.

Results:Men from the highest baseline flexibility tertile were at lower risk of tension neck than those from the lowest tertile (odds ratio (OR) 0.51, 95% confidence interval (CI) 0.28 to 0.93). Women from the highest baseline endurance strength tertile were at lower risk of tension neck than those from the lowest tertile (OR 0.60, 95% CI 0.40 to 0.91). Men from the highest baseline endurance strength tertile were at higher risk of knee injury than those from the lowest tertile (OR 1.96, 95% CI 1.05 to 3.64). Men who at school age participated in physical activity were at lower risk of recurrent low back pain (OR 0.61; 95% CI 0.42 to 0.88) than those who did not.

Conclusions:Overall good flexibility in boys and good endurance strength in girls may contribute to a decreased risk of tension neck. High endurance strength in boys may indicate an increased risk of knee injury.
Optimising a curriculum for clinical haematology and biochemistry in sports medicine: a Delphi approach
Authors: Fallon K E , Trevitt A C
Published: January 2006

Objectives:To investigate issues of curriculum in the context of a postgraduate sports medicine training programme, specifically in the field of clinical biochemistry and haematology.

Methods:Following the Delphi methodology, a series of sequential questionnaires was administered to curriculum developers, clinical teachers, examiners, and registrars.

Results:Agreement on a core syllabus for this subject with an indication of the core aims and objectives of teaching and learning in this field and the associated required skills and competencies. An indication of current and ideal teaching and learning methods and reasons for these preferences. A consensus of key features of a teaching module for this field and of appropriate methods of examination.

Conclusions:The data derived from this study, as well as the experience of engaging in it, will better inform curriculum developers, teachers, and students of one another’s perceptions as to what is important in and appropriate to teaching and learning in this field of sports medicine. Engagement in the exercise and broader consideration of the outcomes by those who develop the curriculum, teach, and formulate the examination process will facilitate attainment of the ideal of well aligned teaching, learning, and examination in this specific field.
Converging evidence for the under-reporting of concussions in youth ice hockey
Authors: Williamson I J S , Goodman D
Published: January 2006

Background:Concussions are potentially serious injuries. The few investigations of prevalence or incidence in youth ice hockey have typically relied on prospective reports from physicians or trainers and did not survey players, despite the knowledge that many athletes do not report probable concussions.

Objective:This study sought to compare concussion rates in youth ice hockey that were estimated from a variety of reporting strategies.

Methods:Rates were calculated from British Columbia Amateur Hockey Association (BCAHA) official injury reports, from direct game observation by minor hockey volunteers (such as coaches and managers), as well as from retrospective surveys of both elite and non-elite youth players. All research was conducted within the BCAHA.

Results:Estimates from official injury reports for male players were between 0.25 and 0.61 concussions per 1000 player game hours (PGH). Concussion estimates from volunteer reports were between 4.44 and 7.94 per 1000 PGH. Player survey estimates were between 6.65 and 8.32 per 1000 PGH, and 9.72 and 24.30 per 1000 PGH for elite and non-elite male youth hockey, respectively.

Conclusion:It was found that concussions are considerably under-reported to the BCAHA by youth hockey players and team personnel.
Effects of aquaculture on wild fish populations: a synthesis of data
Authors: Weir Laura K , Grant James WA
Published: January 2006

The potential adverse environmental effects of aquaculture have been the subject of considerable attention in both the media and the scientific literature. We undertook a synthesis of the published scientific literature, primarily concerning Atlantic salmon (Salmo salar), to assess the current data available regarding these potential effects. No data are available to test for the direct effects of aquaculture organisms on the demographics of wild fish populations. However, seven studies show that escaped salmon in the wild have lower fitness, as measured by survival and reproductive success, than native salmon. Thirteen other studies, encompassing 91 different traits, provide strong evidence of phenotypic differences between farmed and wild salmon, presumably because of artificial selection in the aquaculture environment. An additional 10 studies have documented significant genetic differences between farmed salmon and the wild fish with which they will interact, or potentially interact. Given the paucity of data regarding actual population consequences of escaped farmed fish on wild populations, and the documented differences between the two types of fish, it seems prudent to treat farmed fish as exotic species with potentially negative consequences for wild populations, particularly when the latter are of conservation concern.Key words: aquaculture, Atlantic salmon, artificial selection, fitness, introgression.
Population genetics and conservation of the critically endangeredClematis acerifolia(Ranunculaceae)
Authors: López-Pujol J. , Zhang F.-M. , Ge S.
Published: January 2006

Allozyme electrophoresis was used to evaluate the levels of genetic diversity and population genetic structure of the critically endangered Clematis acerifolia Maximowicz (Ranunculaceae), a narrow endemic species in China. On the basis of variation at 19 putative loci in nine populations covering the entire distribution of this species, low values of genetic diversity were detected (P = 20.5%, A = 1.27, and He= 0.072). A significant deficiency of heterozygotes was found in all populations. Most loci showed deviations from the Hardy–Weinberg equilibrium, probably as a result of population genetic structuring. The high genetic divergence among populations (FST= 0.273) can be interpreted as an effect of the extinction of local populations and genetic drift within extant populations, and has probably been enhanced by habitat fragmentation in recent decades. Threats to this species are mainly anthropogenic (road works, construction of holiday resorts, and extraction activities), although stochastic risks cannot be ignored. Therefore, to preserve extant genetic variation of C. acerifolia, in situ strategies, such as the preservation of its habitat or at least the most diverse populations, and ex situ measures, such as the collection and long-term storage of seeds, should be adopted.
Encasement in plant morphology: an integrative approach from genes to organisms
Authors: Lacroix Christian , Jeune Bernard , Barabé Denis
Published: January 2006

Recent advances in molecular genetics are prompting developmental plant morphologists to refine the theoretical context of their field. For example, at the level of the action of certain developmental genes, the distinction between recognized structural categories (i.e., stem and leaf) are not obvious. This issue has also been analyzed by morphologists from qualitative and quantitative perspectives and has lead to similar conclusions. Consequently, the classical approach to morphology with a typological view of organ categories is no longer sufficient to explain the set of all possible forms. However, within the context of a dynamic morphology, where processes of development such as growth rate, duration, and distribution are considered, a more encompassing view of the generation of form can be achieved. We therefore propose that classical morphology is a subset of dynamic morphology. The main goal of this paper is to show how new concepts and methods of viewing plant morphology allow us to build a conceptual theoretical framework that may have a predictive value with respect to morphological characteristics as well as molecular properties of organs. The main premise of this commentary, within the context of dynamic morphology, is that the plant consists of an encasement of structures or a nesting of partially similar units. Common developmental processes are in operation at each structural level and variations in the modalities of these processes lead to the development of specific structures. Repeating polymorphic sets (RPS) represent an extension of this perspective on plant development and have the potential to predict the existence of new, perhaps unknown forms. The idea of repeating polymorphic sets can also be extended to outline the activity of specific developmental genes to explain how a wide variety of those genes are interrelated during development to specify form.
Elevational gradient of neoformed shoot growth inPopulus tremuloides
Authors: Cox Samuel E.
Published: January 2006

Determinate growth involves cessation of leaf formation prior to the end of the growing season, whereas indeterminate growth involves leaf formation for as long as environmental conditions allow. Quaking aspen ( Populus tremuloides Michx.) has been described as having both types of growth. This variation is partially due to canopy bud position, but environmental factors may also contribute. In this study, buds from the same canopy position of aspen trees in northern Colorado, USA, exhibited less neoformation with increasing elevation (R2= 0.78). Evidence suggests that this is primarily a response to the characteristically cooler temperatures and shorter growing seasons of higher elevations.
The relationship between stem-galling wasps and mycorrhizal colonization of Quercus turbinella
Authors: Mueller Rebecca C. , Sthultz Christopher M. , Martinez Theodore , Gehring Catherine A. , Whitham Thomas G.
Published: January 2006

While numerous studies have examined the relationship between herbivory and mycorrhizal colonization, few studies have been undertaken on plant species such as oaks that can be dually colonized by both arbuscular mycorrhizas (AM) and ectomycorrhizas (EM). We examined the relationship between insect herbivory by a stem-galling wasp (Cynipidae) and the mycorrhizal colonization of shrub live oaks ( Quercus turbinella Greene). We found that oaks with high numbers of galls had 2.4 times higher levels of branch die-back and were 2.3 times more water stressed than oaks with low numbers of galls. Oaks with high numbers of galls supported 21% higher levels of AM colonization but had 53% lower levels of EM colonization than oaks with low numbers of galls. In addition, AM colonization was positively correlated with the number of galls per tree, while EM colonization was negatively correlated with the number of galls per tree. These findings suggest that there is a dynamic relationship between stem-galling wasps and the AM and EM mutualists of shrub live oak.
Genetic diversity of fringed brome (Bromus ciliatus) as determined by amplified fragment length polymorphism
Authors: Fu Yong-Bi , Coulman Bruce E. , Ferdinandez Yasas S.N. , Cayouette Jacques , Peterson Paul M.
Published: January 2006

Fringed brome ( Bromus ciliatus L.) is found in native stands throughout a large area of North America. Little is known about the genetic diversity of this species. The amplified fragment length polymorphism (AFLP) technique was applied to assess the genetic diversity of 16 fringed brome populations sampled in Canada from the provinces of Alberta, British Columbia, Quebec, and Saskatchewan. Four AFLP primer pairs were employed to screen 82 samples with four to six samples per population and 83 polymorphic AFLP bands scored for each sample. The frequencies of the scored bands in all assayed samples ranged from 0.01 to 0.99 and averaged 0.53. Analysis of molecular variance revealed that 52.6% of the total AFLP variation resided among the 16 populations and 20.6% among the four provinces. The five Quebec populations appeared to be genetically the most diverse and distinct. The AFLP variability observed was significantly associated with the geographic origins of the fringed brome populations. These findings are useful for sampling fringed brome germplasm from natural populations for germplasm conservation and should facilitate the development of genetically diverse regional cultivars for habitat restoration and revegetation.
Temporal evolution and nature of TiFeP mineralization in the anorthositemangeritecharnockitegranite (AMCG) suites of the south-central Grenville Province, Saguenay  Lac St. Jean area, Quebec, Canada
Authors: Hébert Claude , Cadieux Anne-Marie , Breemen Otto van
Published: January 2006

In the south-central Grenville Province, Quebec, Canada, anorthositemangeritecharnockitegranite (AMCG) magmatism took place during four distinct episodes between 1327 and 1008 Ma. AMCG rocks crosscut several gneiss complexes composed of ~1506 Ma supracrustal rocks and massive to gneissic igneous rocks that were emplaced during two distinct episodes: ~1434 and 13931383 Ma. The four episodes of AMCG magmatism are (i) the 1327 ± 16 Ma labradorite-type De La Blache Mafic Plutonic Suite, (ii) the 11601135 Ma labradorite- and andesine-type Lac St. Jean Anorthositic Suite, (iii) a 10821045 Ma unnamed plutonic suite, and (iv) the 10201008 Ma andesine-type Valin Anorthositic Suite. The Valin Anorthositic Suite includes the 1016 ± 2 Ma andesine-type Mattawa Anorthosite, the 10101008 Ma andesine-type Labrieville Alkalic Anorthositic Massif, the 1020 ± 4 Ma St. Ambroise Pluton, the 1018+73 Ma Farmer Monzonite; the 1010 ± 2 Ma Gouin Charnockite, and the 1010 ± 3 Ma La Hache Monzonite. Study of the TiTeP mineral occurrences in these four AMCG units in the south-central Grenville Province has shown that (i) apatite-bearing rocks are related only to andesine-type anorthosites, (ii) titaniferous magnetite is restricted to labradorite-type anorthosites, and (iii) hemo-ilmenite occurs only in andesine-type anorthosite and associated oxideapatite-rich gabbronorites (OAGN) and nelsonites.
Metallogeny of the Grenville Province revisited
Authors: Gauthier Michel , Chartrand Francis
Published: January 2006

Four new petrogenetic and metallogenic models are proposed herein to explain the formation of important mineral deposits in the Grenville Province, providing a framework from which to reappraise Grenvillian mineral potential. Recognition of a high-pressure metamorphic belt within the Grenville Province suggests a potential for eclogite-hosted rutile deposits, an important and much-sought commodity. A recently developed Norwegian model proposes that anorthosite genesis occurred through lower crust underplating and coeval partial melting, rather than by plume magmatism. Applied to the Grenville Province, the new petrogenetic model may provide insight into the widespread occurrence of platinum group element (PGE) poor nickel showings and the distribution of chromite, Ti-rich, and low-Ti iron-oxide deposits within the Grenville and adjacent terranes. A new type of sedimentaryexhalative (SEDEX) mineralization formed by oxidized brines has been defined following the discovery of new deposits in Australia. Applied to the Grenville Province, it provides a possible explanation for two long-recognized features of marble-hosted zinc deposits: (i) the presence of meta-siderite beds occurring as distal haloes around SEDEX zinc deposits, and (ii) the mutually exclusive division of these SEDEX deposits into massive sulphide and nonsulphide groups. The discovery of the giant Olympic Dam iron-oxide coppergold (IOCG) deposit in Australia renewed the interest in magmatic low-Ti iron-oxide deposits in the Grenville Province that have been known and mined since early colonial times. Subsequent exploration in the northeastern part of the Grenville Province revealed the presence of breccia-hosted CuAuU  rare-earth element (REE)-bearing iron-oxide mineralization. This deposit and other low-Ti iron-oxide deposits in the southwestern Grenville Province have a previously undocumented close spatial and temporal association with Ti-rich iron-oxide deposits. These examples demonstrate how new petrogenetic, tectonic, and ore deposit models developed in unmetamorphosed rocks can be successfully adapted to high-grade terranes, where they stimulate mineral exploration in these challenging conditions. Furthermore, by tracking the formation of ore deposits in the lower crust, the existence of unsuspected metallogenic associations in the higher crust, such as the low-Ti and high-Ti iron-oxide association observed in the Grenville Province, may be revealed.
Styles of Proterozoic crustal growth on the southeast margin of Laurentia: evidence from the central Grenville Province northwest of Lac St.-Jean, Quebec
Authors: Martin C , Dickin A P
Published: January 2006

The southeast margin of Laurentia was a very long lived active continental margin, part of whose history is recorded in the Grenville Province of the Canadian Shield. Within this province, Nd-isotope mapping can be used to define the boundaries between terranes with a variety of crustal formation ages and can also distinguish between crustal growth by oceanic and continental-arc magmatism. The former gives rise to large terranes with homogeneous Nd-isotope signatures and well-defined boundaries, whereas the latter leads to areas with heterogeneous Nd-isotope signatures. One of the best examples of continental-arc magmatism in the Grenville Province is provided by the region northwest of Lac St.-Jean, Quebec. Eighty new Nd-isotope analyses are used (along with aeromagnetic data) to divide this area into three blocks, bounded by abrupt changes in Nd model age. The western block consists almost exclusively of tonalitic grey gneisses with Archean model ages. The eastern block is composed almost exclusively of gneisses with Nd model ages of 1.61.5 Ga and tonalitetrondhjemitegranodiorite-type chemistry. In contrast, the central block has a wide range of Nd-isotope signatures and more alkaline major element chemistry characteristic of an ensialic arc. The εNd values in this block correlate with distance southeast of the Allochthon Boundary Thrust, suggesting that ensialic arc magmas suffered diminishing contamination in a southeastward direction by old Laurentian crust. A subduction-flip model is proposed, whereby north-dipping subduction under the continental margin followed the accretion of a Mesoproterozoic arc terrane to the Laurentian craton.
Lower Ordovician trilobites from the Baumann Fiord Formation, Ellesmere Island, Arctic Canada
Authors: Adrain Jonathan M , Westrop Stephen R
Published: January 2006

Sections through member B of the Baumann Fiord Formation on the Bache Peninsula, Ellesmere Island, Arctic Canada, contain a range of lithofacies indicating deposition in shallow subtidal settings above storm wave base. Macrofossils are generally rare, but low-diversity trilobite-dominated faunas occur in a section near Sanddöla Creek. The only other fossils common in the collections are poorly preserved gastropods. All of the trilobite species are apparently new, and four are formally named: Licnocephala sanddoelaensis, "Peltabellia" baumannensis, Bolbocephalus ellesmerensis, and Ceratopeltis bachensis. The species Ceratopeltis forteyi is introduced for material previously described from North Greenland. Rare additional species of Licnocephala and Jeffersonia are reported in open nomenclature. The trilobites occur in three stratigraphically and lithologically distinct associations, with species diversity ranging from two to four. Closest comparisons of the trilobite species all indicate that member B should be assigned to the Tulean Stage of the Ibexian Series. Rananasus Cullison, 1944, is placed in synonymy of Bolbocephalus Whitfield, 1890.
Crustal development at the pre-Grenvillian Laurentian margin: a record from contrasting geochemistry of mafic and ultramafic orthogneisses in the Chochocouane River area, Quebec
Authors: La Flèche M R , Birkett T C , Corriveau L
Published: January 2006

Mafic and ultramafic orthogneisses from the western Grenville Province of Quebec adjacent to the Archean Superior Province (Canada) display geochemical characteristics that highlight processes that shaped the pre-Grenvillian Laurentian margin through late Archean to Mesoproterozoic time. Group I mafic and ultramafic granulites of the Parautochthonous Belt compositions overlap Archean Abitibi metavolcanic rocks (komatiites to Fe-rich andesites) supporting their autochthonous character. Limited variation of incompatible trace-element ratios with increasing differentiation suggests minimal sialic crust assimilation during petrogenesis and probable formation in an oceanic setting. Group II mafic tholeiites occur within both the Parautochthonous Belt and the Allochthonous Polycyclic Belt. Their compositions differ significantly from those of Archean rocks but overlap those of Proterozoic and modern continental tholeiites. Group III mafic calc-alkaline amphibolites, predominantly in the Allochthonous Polycyclic Belt, display chemical characteristics expected of magma derivation from subducted oceanic crust. In contrast to group I Archean meta-igneous rocks metamorphosed during the Kenoran orogeny, group III rocks do not record an early phase of large-ion lithophile element (LILE) metasomatism and granulite-facies metamorphism. As such, their emplacement is interpreted to postdate the Archean Kenoran metamorphism and to be Proterozoic in age. Group I rocks reflect an Archaean ensimatic greenstone belt environment; group II tholeiites reflect a Proterozoic continental rift environment; and group III rocks reflect a subduction-related source, possibly related to Andean-style, calc-alkaline magmatism.
Generation of a heavy-mineral glacial indicator dispersal train from a diabase sill, Nipigon region, northwestern Ontario
Authors: Larson Phillip , Mooers Howard
Published: January 2006

The heavy clinopyroxene mineral pigeonite forms a glacial indicator dispersal train originating from diabase intrusions in the Nipigon region of northwestern Ontario. Analysis and interpretation of the pigeonite dispersal pattern adjacent to the up-ice portion of the diabase provides a number of insights into the nature of glacial erosion of bedrock and the generation of heavy-mineral dispersal trains. Bedrock erosion and entrainment rates at the time of pigeonite dispersal train formation were high (314 mm·a1), suggesting that bedrock erosion was rapid yet spatially and temporally restricted. Contrasting erosion rates between the diabase and surrounding greenstone lithologies suggests that modern shield topography is not an assemblage of equilibrium bedforms with respect to the ice sheet. This agrees with hypothesized low total erosion of shield bedrock during the Pleistocene. Pigeonite grain size coarsens over the diabase source, indicating that most of the pigeonite was quarried from outcrops as coarse diabase fragments. Down-ice of the diabase source the mean particle size of pigeonite recovered from till decreases, suggesting most of the pigeonite was liberated from bedrock by the comminution of coarse diabase clasts during glacial transport. While the conclusions drawn from this study may not necessarily apply to all heavy-mineral dispersal trains, the interpretive framework provides a foundation for comparative studies.
Foraging selectivity by larval yellow perch (Perca flavescens): implications for understanding recruitment in small and large lakes
Authors: Fulford Richard S , Rice James A , Miller Thomas J , Binkowski Fred P , Dettmers John M , Belonger Brian
Published: January 2006

Growth and survivorship of larval yellow perch (Perca flavescens) have been examined in many systems but can conclusions from well-studied perch populations in smaller lakes be applied to populations in meso-oceanic systems like Lake Michigan, USA? Laboratory experiments were conducted with yellow perch (hatch to 35 mm total length) to develop an empirical selectivity function based on Chesson's α to describe larval diet as a function of changes in prey community composition. This function was used in an individual-based foraging and growth model (IBM) to describe changes in foraging decisions resulting from changes in prey composition between different systems. Larval perch made three selective transitions during ontogeny. Initial positive selection for rotifers and the relative selectivity for cladocerans vs. copepods in late-stage larvae were both dependent on prey composition. Larvae exposed to prey assemblages differing only in composition had different diets. The empirically based IBM accurately predicted these dietary differences and resulting differences in larval growth and likelihood of starvation between systems at equal prey density. The importance of feeding behavior to larval survival will differ between Lake Michigan and smaller lakes, and these results are important for comparisons of recruitment dynamics between large and small systems.