bluuebunny/crossref_metadata_2025 huggingface dataset:
Melatonin attenuates the postischemic increase in blood–brain barrier permeability and decreases hemorrhagic transformation of tissue‐plasminogen activator therapy following ischemic stroke in mice
Authors: Chen Tsung‐Ying , Lee Ming‐Yang , Chen Hung‐Yi , Kuo Yen‐Liang , Lin Shih‐Chieh , Wu Tian‐Shung , Lee E‐Jian
Published: January 2006

Abstract:  Melatonin protects against transient middle cerebral artery (MCA) occlusion and may be suited as an add‐on therapy of tissue plasminogen activator (t‐PA) thrombolysis. Herein, we examined whether melatonin would reduce postischemic increase in the blood–brain barrier (BBB) permeability and, therefore, attenuate the risk of hemorrhagic transformation after t‐PA therapy in experimental stroke. Twelve mice were subjected to transient occlusion of the MCA for 1 hr, followed by 24 hr of reperfusion. Melatonin (5 mg/kg, i.p.) or vehicle was given at the beginning of reperfusion. BBB permeability was evaluated by quantitation of Evans Blue leakage. An additional 32 mice underwent photothrombotic occlusion of the distal MCA, and were administered vehicle or t‐PA (10 mg/kg, i.v.), alone or in combination with melatonin (5 mg/kg, i.p.), at 6 hr postinsult. The animals were then killed after 24 hr for the determination of infarct and hemorrhage volumes. Relative to controls, melatonin‐treated animals had significantly reduced BBB permeability (by 52%; P < 0.001). Additionally, we found that at 6 hr after photo‐irradiation, either t‐PA or melatonin, or a combined administration of t‐PA plus melatonin, did not significantly affect brain infarction (P > 0.05), compared with controls. Mice treated with t‐PA alone, however, had significantly increased hemorrhagic formation (P < 0.05), and the event was effectively reversed by co‐treatment with melatonin (P < 0.05). Thus, melatonin improved postischemic preservation of the BBB permeability and a decreased risk of adverse hemorrhagic transformation after t‐PA therapy for ischemic stroke. The findings further highlight melatonin's potential role in the field of thrombolytic treatment for ischemic stroke patients.
Axonal Transport of Microtubules: the Long and Short of It
Authors: Baas Peter W. , Vidya Nadar C. , Myers Kenneth A.
Published: January 2006

Recent studies on cultured neurons have demonstrated that microtubules are transported down the axon in the form of short polymers. The transport of these microtubules is bidirectional, intermittent, asynchronous, and occurs at the fast rate of known motors. The majority of the microtubule mass in the axon exists in the form of longer immobile microtubules. We have proposed a model called ‘cut and run’, in which the longer microtubules are mobilized by enzymes that sever them into shorter mobile polymers. In this view, the molecular motors that transport microtubules are not selective for short microtubules but rather impinge upon microtubules irrespective of their length. In the case of the longer microtubules, these motor‐driven forces do not transport the microtubules in a rapid and concerted fashion but presumably affect them nonetheless. Here, we discuss the mechanisms by which the short microtubules are transported and suggest possibilities for how analogous mechanisms may align and organize the longer microtubules and functionally integrate them with each other and with the actin cytoskeleton.
Oral lesions in elderly population: a biopsy survey using 2250 histopathological records
Authors: Corrêa Luciana , Frigerio Maria Luiza Moreira Arantes , de Sousa Suzana Cantanhede Orsini Machado , Novelli Moacyr Domingos
Published: January 2006

Objective:  To perform an oral biopsy survey focused on the incidence of oral lesions in Brazilian elderly patients.

Methods:  A total of 17 329 oral biopsy records were analysed and divided into two age groups: elderly patients, ≥60 years old; and non‐elderly patients, <60 years old. Information about sex, race, age and histopathological diagnosis (categorised in non‐neoplastic and neoplastic lesions) was collected. Differences of diagnosis incidence were tested by comparison between two proportions (binomial test).

Results:  The incidence of epithelial malignant neoplasms and pre‐malignant lesions in the elderly group was higher than non‐elderly group, as well as autoimmune diseases and salivary gland tumours. The three most prevalent lesions in the elderly group were inflammatory fibrous hyperplasia, squamous cell carcinoma, and fibroma.

Conclusion:  The distribution of oral diseases using biopsies allows greater accuracy in data about oral health of elderly patients, especially when considering malignant and pre‐malignant lesions.
The effect of denture quality attributes on satisfaction and eating difficulties
Authors: Anastassiadou Vassiliki , Robin Heath M.
Published: January 2006

Objectives:  The development of a measure, with complimentary normative and perceived needs, for the investigation of functional impairment of individual patients and the investigation of the physical causative bases of impairment.

Subjects:  A consecutive sample of 119 complete denture (CD) wearers attending a Greek department of prosthetic dentistry took part in the study. All subjects presented with some complaint(s) of their dentures.

Method:  Functional assessment of dentures (FAD) criteria and structured questionnaires were used covering denture satisfaction (DS) and food difficulties with CDs. The questions used a five‐point Likert scale.

Results:  The results showed that there were statistically significant associations between satisfaction from dentures and eating specified foods. Statistically significant associations were also found between denture qualities and movement of upper dentures and difficulty eating specified foods, but not with an open question on the difficulty of eating unspecified foods.

Conclusions:  This study successfully validated a suitable model for the combined evaluation of denture quality with clear diagnostic criteria and closed questions on DS and perceived difficulties when eating specified foods. This could predict the need for treatment, monitor the impact of care and provide a feasible measure to meet the need of everyday clinical situations.
In vitro biocompatibility of denture relining materials
Authors: Dahl Jon E. , Frangou‐Polyzois Mary J. , Polyzois Gregory L.
Published: January 2006

Objective:  The aim of the present study was to evaluate the in vitro biocompatibility of denture relining materials using cell culture tests and a test for irritation mechanisms.

Background:  Denture relining materials contain non‐reacted constituents that may leach out during use inducing local toxic or irritative effects.

Materials and methods:  One chemically cured, four visible light cured and five dual‐cured products were included. Cured test specimens were used for the filter diffusion test, and extracts of cured specimens were applied in the MTT and the irritation test using the hen's egg test‐chorioallantoic membrane (HET‐CAM) method.

Results:  Five of the tested materials were slightly or moderately cytotoxic in the filter diffusion test, and one product coated with a liner induced severe toxicity. Cell cultures incubated for 24 hour with the test samples were more damaged than those incubated for 2 hour. In the MTT test, extracts of nine of the 11 products induced cytotoxicity. No extracts showed irritation, whereas the coating and two bonding agents tested were strong irritants.

Conclusion:  Most of the tested materials contained water soluble, toxic substances that leach out of the products and that some time was needed to obtain cytotoxic amounts of the leachables. Many dental materials elicit cytotoxic response, but this does not necessarily reflect the long‐term risk for adverse effects as the oral mucosa is generally more resistant to toxic substances than a cell culture.
QUALITY CHARACTERISTICS AND STORAGE STABILITY OF CHICKEN PATTIES FORMULATED WITH FINGER MILLET FLOUR (ELEUSINE CORACANA)
Authors: NAVEENA B.M. , MUTHUKUMAR M. , SEN A.R. , BABJI Y. , MURTHY T.R.K.
Published: January 2006

In this study, the effect of different levels of ragi or finger millet (Eleusine coracana) flour (0, 2.5, 5.0 and 7.5%) on chemical composition, cooking characteristics, instrumental color and sensory properties of chicken patties was evaluated. Incorporation of ragi flour (RF) had no significant effect on fat or protein content of cooked patties. However, RF significantly (P < 0.05) reduced the shrinkage from 6.01 to 4.75%. Patties formulated with RF had the smallest reduction in diameter and thickness. The use of RF reduced the pH of cooked patty from 6.68 to 6.57. RF incorporation at all levels resulted in lower (P < 0.05) Commission Internationale de l'Eclairage lightness (L*) and yellowness (b*) values compared with control. Chicken patties formulated with RF had acceptable sensory scores. On the basis of physicochemical and sensory characteristics, incorporation of RF up to 5% was optimal. Storage stability of chicken patties formulated with 0 (control) and 5% RF was examined during 21 days of refrigerated storage (4 ± 1C). The pH and the thiobarbituric acid value values increased (P < 0.05) from 6.58 to 6.68 and from 0.41 to 0.72, respectively, during storage. Aerobic plate counts increased (P < 0.05) from 2.97 to 5.32 and from 2.98 to 5.39 for control and ragi patties, respectively. Hunter L* and redness values did not change (P > 0.05) during storage, whereas b* values generally decreased with increasing storage. All sensory attributes declined (P < 0.05) as storage time increased.
A Two‐Tiered Approach to Reactive Transport: Application to Sr Mobility Under Variable pH
Authors: Toran Laura , Bryant Steve , Saunders James , Wheeler Mary F.
Published: January 2006

One benefit of a coupled geochemistry/transport approach is that interactions between chemical constituents that can change the mobility of species (such as pH) can be treated explicitly, rather than lumping all of the geochemistry into a single term (i.e., the retardation factor). A two‐tiered approach to modeling coupled geochemistry/transport is presented here, which allows a comparison of the results of different methods as well as better efficiency in modeling time. The codes ParSSim, a coupled transport code for supercomputers, and PHREEQC, an advective geochemistry code, were used to model Sr mobility under varying pH. The problem was based on liquid low level radioactive waste that was disposed at Oak Ridge National Laboratory (Oak Ridge, Tennessee) in a highly alkaline solution to try to enhance precipitation and sorption. Interactions with carbonate rock and ground water lowered the pH and led to mobilization of radionuclides such as 90Sr. Simulation of contaminant migration in this mixing environment requires a coupled geochemistry and transport model. The interplay between propagation of a pH front (which was retarded) and propagation of the Sr front leads to a fast‐moving pulse of Sr as well as a strongly retarded front of Sr. This behavior could not have been predicted by a geochemistry or a transport code alone.
A Measurement System to Determine Water Flux and Solute Transport Through Fractures in the Unsaturated Zone
Authors: Dahan Ofer , Nativ Ronit , Adar Eilon , Berkowitz Brian
Published: January 2006

A new methodology was developed for the in situ investigation of flow and transport processes through undisturbed, discrete fractures in the vadose zone. The experimental setup and technical means were designed for a scale of several meters, larger than any conceivable laboratory experiment. The setup consists of four components: (1) a 25 cm diameter horizontal borehole is core‐drilled along a vertical, discrete fracture plane, exposing the fracture at the borehole ceiling; (2) compartmental ponds are installed along the traced fracture on the horizontal part of the outcrop. Each compartment (25 cm long) is connected to a separate feeding source, which can be tagged by a different tracer, and the water head is electronically controlled. Thus, each segment of the exposed fracture could be subjected to a different flux with a specific tracer under a constant hydraulic head; (3) a compartmental sampler, divided into 20 cm long cells, is installed beneath the compartmental ponds in the horizontal borehole. The effluent draining from a particular fracture segment is collected by individual cells of the sampler; (4) the percolating fluids accumulating in the various sampler cells are frequently drained by a collection system into individual sampling vessels.

This experimental setup was field‐tested with untagged water in preliminary experiments in fractured chalk. It can provide unique and important information about flowpath distributions along a natural fracture, and about the chemical evolution of the solutions percolating through the fractures.
Determination of Variances for Maximum and Minimum Transmissivities of Anisotropic Aquifers from Multiple Well Pumping Test Data
Authors: Kern John W. , Dobson Carl W.
Published: January 2006

An extension of the least squares method given by Neuman et al. (1984) for estimating aquifer parameters is presented, and statistical tests for anisotropy are derived. Methods are also given to construct variance formulas for the principal axes of trans‐missivity and confidence intervals for the angles of orientation. The techniques developed here treat each monitoring well as the experimental unit, in contrast to inverse modeling methods which treat each time step for each well as the experimental unit. We argue that the latter is a form of pseudo‐replication in that the number of time steps may be arbitrarily selected.

The example aquifer test data used by Neuman et al. (1984) are analyzed. The maximum transmissiviy was found to have a magnitude of 8.60 ± 5.30 m2/day oriented N29.6°W ± 11.3° at the 95% confidence level with a ratio of anisotropy of 1.91 ± 0.39. Both statistical tests indicated anisotropy. Results from a multiple well pumping test from the Powder River Basin, Wyoming, are also analyzed. The maximum transmissivity was found to have a magnitude of 230 m2/day ± 84.4 m2/day oriented N51.7°W ± 5.3° at the 95% confidence level with a ratio of anisotropy of 2.12 ± 0.48. Both statistical tests indicated anisotropy.

The methods given in this paper can be performed with standard statistical software packages and spreadsheets. A program that uses Matlab® software is available from the authors to perform the necessary calculations at ftp2.wyoming.com/pub/users/FTP/west‐inc/groundwater/adapl.zip.
Experimental Evaluation of Factors Affecting Temporal Variability of Water Samples Obtained from Long‐Screened Wells
Authors: Reilly Thomas E. , LeBlanc Denis R.
Published: January 2006

As a well is pumped through time, concentrations of specific constituents in the water discharging from the well may change as a result of their transport within the well and the aquifer. A series of experiments conducted at a research site on Cape Cod, Massachusetts, examined the effects of transport on the chemistry of water samples obtained from a long‐screened well. Analyses of time series of constituent concentrations in water pumped from the long‐screened well showed persistent temporal trends during the first experiment. Iron concentrations decreased over a five‐hour test (15 casing volumes), whereas the calcium and magnesium concentrations increased. In contrast, the time series of constituent concentrations of water discharging from the same well showed less change with time during a later experiment. Numerical simulations were undertaken to test the relative importance of several possible factors affecting the temporal variations of these constituents. During the process of quantitatively explaining the changes in concentrations over time observed in the two experiments, different system conceptualizations were used, including (1) flow and transport in the aquifer without wellbore transport, (2) flow and transport in the aquifer with advective flow and transport in the wellbore, and (3) flow and transport in the aquifer with advective flow and transport in the wellbore and a thin layer (skin) of water surrounding the well with constituent concentrations that had been altered by the presence of the well. The conjectured skin of wellbore water, which could have invaded the aquifer because of nearby sampling or dispersion and diffusion near the wellbore, in conjunction with flow and transport in the aquifer and advective transport within the wellbore, produced a reasonable match between the simulated and observed concentrations. The data analysis confirms the known fact that long‐screened wells provide mechanisms for the redistribution of chemical constituents in the aquifer. The analysis provides new insight into the mechanisms responsible for the observed changes in concentrations during the sampling of long‐screened wells. The analysis quantifies the effects of the various conceptual models of flow and transport in and around wells on the interpretation and meaning of chemical analyses of water withdrawn from long‐screened wells.
Reductive Dissolution and Reactive Solute Transport in a Sewage‐Contaminated Glacial Outwash Aquifer
Authors: Lee Roger W. , Bennett Phillip C.
Published: January 2006

Contamination of shallow ground water by sewage effluent typically contains reduced chemical species that consume dissolved oxygen, developing either a low oxygen geochemical environment or an anaerobic geochemical environment. Based on the load of reduced chemical species discharged to shallow ground water and the amounts of reactants in the aquifer matrix, it should be possible to determine chemical processes in the aquifer and compare observed results to predicted ones.

At the Otis Air Base research site (Cape Cod, Massachusetts) where sewage effluent has infiltrated the shallow aquifer since 1936, bacterially mediated processes such as nitrification, denitritication, manganese reduction, and iron reduction have been observed in the contaminant plume. In specific areas of the plume, dissolved manganese and iron have increased significantly where local geochemical conditions are favorable for reduction and transport of these constituents from the aquifer matrix. Dissolved manganese and iron concentrations ranged from 0.02 to 7.3 mg/L, and 0.001 to 13.0 mg/L, respectively, for 21 samples collected from 1988 to 1989.

Reduction of manganese and iron is linked to microbial oxidation of sewage carbon, producing bicarbonate and the dissolved metal ions as by‐products. Calculated production and flux of CO2 through the unsaturated zone from manganese reduction in the aquifer was 0.035 g/m2/d (12% of measured CO2 flux during winter). Manganese is limited in the aquifer, however. A one‐dimensional, reaction‐coupled transport model developed for the mildly reducing conditions in the sewage plume nearest the source beds showed that reduction, transport, and removal of manganese from the aquifer sediments should result in iron reduction where manganese has been depleted.
DNAPL Transport Through Macroporous, Clayey Till Columns
Authors: Jørgensen Peter R. , Broholm Kim , Sonnenborg Torben O. , Arvin Erik
Published: January 2006

This paper provides the first experimental determination of the rates and distribution of transport of a dense, nonaqueous phase liquid (DNAPL) through a naturally bioporous and fractured clayey till deposit. Until now, assessment of DNAPL behavior in this type of deposit has relied on theoretical studies. Predictions of DNAPL transport have proven to be uncertain as a result of difficulties in measuring critical parameters such as DNAPL entry pressure and flow behavior in response to natural fracture/biopore apertures and the degree of interconnection of these structures. In the present investigation, the migration of free product trichloroethylene (TCE) was studied by means of two undisturbed clayey till columns (dimensions: 0.5 m diameter by 0.5 m long) under in situ effective soil stress conditions. The experiments revealed that transport of TCE was restricted to biopores in one column and fractures in another column, bypassing the low‐permeability clayey matrix. Effective porosities of the columns, i.e., bio‐pores and fractures, were two to three orders of magnitude lower than total porosities (25% and 32%, respectively, for the two columns), i.e., macropores and matrix. Single phase water flow rates through the columns at water‐saturated conditions followed a linear relationship with hydraulic gradient. TCE flow could not be predicted from the single‐phase calculations because of non‐linearity observed between applied TCE injection heads and resulting TCE flow. TCE flow rates were 24 and 10.3 m/day at TCE gradients of 1.18 and 0.91, respectively. The observed flow rates indicate that in cases where vertical biopores or fractures fully penetrate clayey till aquitards, a low‐viscosity DNAPL (e.g., TCE) may quickly enter underlying aquifers. The experiments further indicate that 100 liters of a low‐viscosity DNAPL are sufficient to contaminate approximately 25 to 100 m3 of till material because of the small effective porosity constituted by the biopores and fractures.
Clinical Evaluation of Macrolide-Resistant
Mycoplasma pneumoniae
Authors: Suzuki Satowa , Yamazaki Tsutomu , Narita Mitsuo , Okazaki Norio , Suzuki Isao , Andoh Tomoaki , Matsuoka Mayumi , Kenri Tsuyoshi , Arakawa Yoshichika , Sasaki Tsuguo
Published: January 2006

Macrolide-resistant
Mycoplasma pneumoniae
(MR
M. pneumoniae
) has been isolated from clinical specimens in Japan since 2000. A comparative study was carried out to determine whether or not macrolides are effective in treating patients infected with MR
M. pneumoniae
. The clinical courses of 11 patients with MR
M. pneumoniae
infection (MR patients) treated with macrolides were compared with those of 26 patients with macrolide-susceptible
M. pneumoniae
infection (MS patients). The total febrile days and the number of febrile days during macrolide administration were longer in the MR patients than in the MS patients (median of 8 days versus median of 5 days [
P
= 0.019] and 3 days versus 1 day [
P
= 0.002], respectively). In addition, the MR patients were more likely than the MS patients to have had a change of the initially prescribed macrolide to another antimicrobial agent (63.6% versus 3.8%; odds ratio, 43.8;
P
< 0.001), which might reflect the pediatrician's judgment that the initially prescribed macrolide was not sufficiently effective in these patients. Despite the fact that the febrile period was prolonged in MR patients given macrolides, the fever resolved even when the initial prescription was not changed. These results show that macrolides are certainly less effective in MR patients.
A Porphyrin Increases Survival Time of Mice after Intracerebral Prion Infection
Authors: Kocisko David A. , Caughey Winslow S. , Race Richard E. , Roper Grant , Caughey Byron , Morrey John D.
Published: January 2006

Prion diseases, including scrapie, are incurable neurodegenerative disorders. Some compounds can delay disease after a peripheral scrapie inoculation, but few are effective against advanced disease. Here, we tested multiple related porphyrins, but only Fe(III)
meso
-tetra(4-sulfonatophenyl)porphine injected into mouse brains after intracerebral scrapie inoculation substantially increased survival times.
Is it more effective for highly trained swimmers to live and train at 1200 m than at 1850 m in terms of performance and haematological benefits?
Authors: Roels B , Hellard P , Schmitt L , Robach P , Richalet J-P , Millet G P
Published: January 2006

Objectives:The effects of living and training have not been compared at different altitudes in well trained subjects.

Methods:Nine international swimmers lived and trained for 13 days similarly at 1200 m (T1200) and 1850 m (T1850). The two altitude training periods were separated by six weeks of sea level training. Before and after each training trip, subjects performed, at an altitude of 1200 m, an incremental exercise test to exhaustion of 5 × 200 m swims and a maximal test over 2000 m.

Results:There was no difference in V˙o2maxafter each training trip: the before values were 58.5 (5.6) and 60.4 (6.7) ml/kg/min and the after values were 56.2 (5.2) and 57.1 (4.7) ml/kg/min for T1200 and T1850 respectively. The 2000 m performance had improved during T1200 (1476 (34) to 1448 (45) seconds) but not during T1850 (1458 (35)v1450 (33) seconds). Mean cell volume increased during T1850 (86.6 (2.8) to 88.7 (2.9) µm3) but did not change during T1200 (85.6 (2.9)v85.7 (2.9) µm3). The proportion of reticulocytes decreased during T1200 (15.2 (3.8)% to 10.3 (3.4)%) and increased during T1850 (9.3 (1.6)% to 11.9 (3.5)%).

Conclusions:The short term effects of 13 days of training at 1200 m on swimming performance appear to be greater than the same type of training for the same length of time at 1850 m. As mean cell volume and proportion of reticulocytes only increased during training at 1850 m, the benefits of training at this altitude may be delayed and appear later on.
Injuries in West Indies cricket 2003–2004
Authors: Mansingh A , Harper L , Headley S , King-Mowatt J , Mansingh G
Published: January 2006

Objective:To analyse injuries in West Indies Cricket and compare them with those of other cricket playing nations.

Methods:Injuries between June 2003 and December 2004 were surveyed prospectively in all major matches of the West Indies Cricket Board.

Results:Most injuries occurred in the West Indies Test and one day international teams. Mean match injury incidence was 48.7 per 10 000 player-hours in Test cricket, and 40.6 per 10 000 player-hours in one day international cricket, with injury prevalence of 11.3% and 8.1% respectively. In domestic cricket, the match injury incidence was 13.9 per 10 000 player-hours for first class cricket, and 25.4 per 10 000 player-hours in one day domestic competitions. There were more injuries on tour for the West Indies team than at home. The batsmen and fast bowlers sustained 80% of injuries, with many leading to long absence from the game, although many of these injuries were sustained while fielding. Most injuries were of the phalanges (22%) and the lumbar spine (20%) sustained mainly while fielding (including catching) and fast bowling respectively.

Conclusions:Injuries in West Indies cricket may be reduced by (a) early detection and management of injuries on tour, (b) attention to fielding and catching techniques, and (c) monitoring of young fast bowlers.
Screening elite winter athletes for exercise induced asthma: a comparison of three challenge methods
Authors: Dickinson J W , Whyte G P , McConnell A K , Harries M G
Published: January 2006

Background:The reported prevalence of exercise induced asthma (EIA) in elite winter athletes ranges from 9% to 50%. Many elite winter athletes do not report symptoms of EIA. At present there is no gold standard test for EIA.

Objective:To establish the efficacy of screening for EIA and examine the role of the eucapnic voluntary hyperventilation (EVH) challenge and laboratory based and sport specific exercise challenges in the evaluation of elite winter athletes.

Methods:14 athletes (mean (SD) age 22.6 (5.7) years, height 177.2 (7.0) cm, body mass 68.9 (16.9) kg) from the Great Britain short-track speed skating (n = 10) and biathlon teams (n = 4) were studied. Each athlete completed a laboratory based and sport specific exercise challenge as well as an EVH challenge, in randomised order.

Results:All 14 athletes completed each challenge. Two had a previous history of asthma. Ten (including the two with a previous history) had a positive test to at least one of the challenges. Ten athletes had a positive response to EVH; of these, only three also had a positive response to the sport specific challenge. No athletes had a positive response to the laboratory based challenge.

Conclusions:Elite athletes should be screened for EIA. EVH is a more sensitive challenge in asymptomatic athletes than sport specific and laboratory based challenges. If sporting governing bodies were to implement screening programmes to test athletes for EIA, EVH is the challenge of choice.
Impact of global change and forest management on carbon sequestration in northern forested peatlands
Authors: Lavoie Martin , Paré David , Bergeron Yves
Published: January 2006

Northern peatlands occupy approximately 4% of the global land surface and store about 30% of the global soil carbon (C). A compilation of C accumulation rates in northern peatlands indicated a long-term average rate of C accumulation of 24.1 g m2 year1. However, several studies have indicated that on a short-time scale and given the proper conditions, these ecosystems can exhibit very high rates of C accumulation (up to 425 g m2 year1). Peatland development is related to precipitation and temperature, and climate change is expected to have an important impact on the C balance of this ecosystem. Given the expected climate change, we suggest that most of the northern forested peatlands located in areas where precipitation is expected to increase (eastern Canada, Alaska, FSU, and Fennoscandia) will continue to act as a C sink in the future. In contrast, forested peatlands of western and central Canada, where precipitation is predicted to decrease, should have a reduction in their C sequestration rates and (or) could become a C source. These trends could be affected by forest management in forested peatlands and by changes in fire cycles. Careful logging, as opposed to wildfire, will facilitate C sequestration in forested peatlands and boreal forest stands prone to paludification while silvicultural treatments (e.g., drainage, site preparation) recommended to increase site productivity will enhance C losses from the soil, but this loss could be compensated by an increase in C storage in tree biomass.Key words: C sequestration, forested peatland, paludification, greenhouse gases, climate change, forest management.
Polyploidy inCrataegusandMespilus(Rosaceae, Maloideae): evolutionary inferences from flow cytometry of nuclear DNA amounts
Authors: Talent Nadia , Dickinson Timothy A.
Published: January 2006

Hawthorns and medlars are closely related genera in Rosaceae subfamily Maloideae, whose taxonomy remains poorly understood. Gametophytic apomixis occurs in polyploids, and diploids are sexual out-crossers, so ploidy level is of great interest, but suitable material for chromosome counts is of limited availability each year. The promise of flow cytometry is that it permits rapid measurement of nuclear DNA amounts from most tissues, and ploidy level can be inferred if climatic and taxonomic differences do not interfere. Our DNA measurements cover most of the taxonomic series in Crataegus , adding cultivated and naturalized Eurasian plants to the many wild plants collected mainly from south-central Canada and the southeastern and northwestern United States. We found that some variation in DNA amount per genome copy distinguishes certain taxa, but ploidy-level estimates are at least as clear as the published chromosome counts, especially in the most common diploid–triploid–tetraploid range, and to the single published higher (hexaploid) chromosome count, we add evidence of pentaploids. By comparing ploidy evaluations to morphology, we hypothesize that both autopolyploidy and allopolyploidy contribute to the taxonomic complexity. We compared DNA amounts in Maloideae with those in Gillenia , a likely sister genus to the subfamily, which has a smaller chromosome number.
Fungi vectored by the introduced bark beetle Tomicus piniperda in Ontario, Canada, and comments on the taxonomy of Leptographium lundbergii, Leptographium terebrantis, Leptographium truncatum, and Leptographium wingfieldii
Authors: Hausner G. , Iranpour M. , Kim J.-J. , Breuil C. , Davis C.N. , Gibb E.A. , Reid J. , Loewen P.C. , Hopkin A.A.
Published: January 2006

Fungi isolated from Tomicus piniperda (L.) galleries in infected trap logs, standing trees, and directly from insects were identified using morphological features and molecular data obtained from the mitochondrial and nuclear DNA region. Identified strains represented Leptographium wingfieldii Morelet, Leptographium procerum (Kendr.) Wingf., Leptographium lundbergii Lag. & Melin sensu Jacobs & Wingfield, Ophiostoma ips (Rumb.) Nannf., Ophiostoma minus (Hedg.) H. & P. Syd., and Sphaeropsis sapinea sensu lato. Leptographium wingfieldii is believed to be a potentially pathogenic introduced fungus, but sequence data suggest a possible connection between it and the teleomorph of Ophiostoma aureum (Robinson-Jeffrey & Davids.) T.C. Harrington (reported from British Columbia and the western United States). Our data also show that the ex-type culture of Leptographium terebrantis Barras & Perry, a species very similar morphologically to L. wingfieldii, also grouped with L. wingfieldii. We also identified strains of Leptographium truncatum (Wingf. & Marasas) Wingf.; this species has been synonymized with L. lundbergii, but our data indicate that these are distinct species, and therefore, the name L. truncatum should be reinstated. We also report the extended presence of L. procerum in Ontario. Previously viewed as a “southern” species frequently associated with pine-root decline diseases, it has been infrequently reported from New York state and but once each from Ontario and Quebec.
Phylogenetic relationships and character evolution in Govenia (Orchidaceae)
Authors: Garcia-Cruz Javier , Sosa Victoria
Published: January 2006

Govenia Lindl. (Orchidaceae) is a neotropical terrestrial deciduous genus of approximately 28 species of the higher Epidendroids. To determine if Govenia is monophyletic and what are the relationships among its species, a phylogenetic analysis based on a detailed morphological study was conducted. Furthermore, the evolution of eight vegetative and floral characters is explored and explained in relation to pollination syndrome. Three most parsimonious trees were retrieved from heuristic searches. Govenia is corroborated as monophyletic with six recognized groups: three monotypic groups (G. ciliilabia, G. powellii, and G. boliviensis) and three major clades (Purpusii, Capitata, and Superba groups). The Purpusii group is characterized by a well-developed rhizome, a solitary leaf, and 3–12 white flowers. The Capitata group is characterized by the lack of a rhizome, two leaves, and 10–30 white flowers. The Superba group is characterized by the lack of a rhizome, two leaves, and numerous yellow flowers. Two trends were identified in Govenia. The first trend is represented by plants with a rhizome and reduced leaf and flower numbers that occur in taxa from the Purpusii group. The second trend has been to increase inflorescence length and the number of flowers, to change flower colour from white to yellow with an ascending position of the column, and is represented in taxa from the Superba group. The evolution of floral characters leads to the hypothesis that there was a shift in pollinator from small bumblebees to larger bumblebees.
Buckle folding and deep-crustal shearing of high-grade gneisses at the junction of two major high-strain zones, Central Gneiss Belt, Grenville Province, Ontario
Authors: Culshaw N
Published: January 2006

Low-plunging, transport-parallel F3 folds are common at all scales in the Central Gneiss Belt of the Grenville Province, but few of these folds are sheath folds. Where the D1D2 Parry Sound shear zone intersects the D3 Shawanaga shear zone (SSZ) at a high angle, F3 folds formed at several scales (centimetre to greater than outcrop scale) in layered D1D2 "straight" gneisses. At the start of their evolution, the F3 folds formed just beyond the SSZ with hinges near orthogonal to the D3 shear direction and with typical buckle features, e.g., wavelengths vary with layer thickness, and hinges are discontinuous and bifurcate. The buckle folds evolved within the SSZ by rotation of hinges towards the shear direction. Even though hinges initiated at a high angle to the shear direction, sheath folds were not produced. In addition to tightening the buckles, the ductile reorientation produced thinthick (extendedshortened) limb pairs and very straight, ridge-like fold hinges and removed small folds from the extended limbs of larger folds. Such features may serve as criteria to distinguish transport-parallel folds that initiated in layering at high angles to the shear direction from those formed in layers containing the shear direction. A general shear parallel to the SSZ can reproduce several features inferred to mark stages in the progressive reorientation of the folds; the pure shear component of the general shear is inferred to have had a positive stretch direction down the dip of the shear zone, at a high angle to the transport (simple shear) direction. The interplay of buckling and shearing in the study area is, plausibly, the expression of deformation at the upper boundary of a channel-like flow that succeeded initial crustal thickening.
UPb age constraints on arenaceous and volcanic rocks of the Wakeham Group, eastern Grenville Province
Authors: Breemen O van , Corriveau L
Published: January 2006

Combined sensitive high-resolution ion microprobe (SHRIMP) and thermal ionization mass spectrometry (TIMS) UPb zircon data from a tightly constrained stratigraphic context of the Wakeham Group provide a precise depositional age for sedimentation within this extensive basin of the Grenville Province. Metavolcanic rocks at the eastern exposure of the Wakeham Group yield ages of 1511 ± 13, 1506 ± 11, 1502 ± 9, and 1491 ± 7 Ma. A crosscutting 1493 ± 10 Ma porphyry vein marks the end of volcanism. The older two volcanic rocks rest stratigraphically above metasediments, with a 1517 ± 20 Ma maximum age of sedimentation derived from the youngest detrital zircons of an arenite. Five 1.611.55 Ga inherited zircons in the volcanics, reinforced by coeval inheritance in nearby plutons, indicate a Labradorian basement source to the supracrustals. The predominant arenite detrital zircons dates are in the 1.951.75 Ga range, however, and feature both trace element and morphological evidence for metamorphism in the source terrane. Together with zircons as old as 2.95 Ga, the detrital age spectrum is consistent with a circum-Superior provenance. The ages obtained imply that Wakeham Group volcanism and sedimentation were, at least in part, coeval with the onset of 1.521.46 Ga Pinwarian plutonism along the southeastern margin of Laurentia. UPb zircon analyses record a late Grenvillian metamorphic event around 1019 Ma. UPb monazite analyses from one sample yield 10101000 Ma ages, and the end of Grenvillian metamorphism is marked by 990 Ma UPb titanite ages.
Chemical imprint of highly metamorphosed volcanic-hosted hydrothermal alterations in the La Romaine Supracrustal Belt, eastern Grenville Province, Quebec
Authors: Bonnet Anne-Laure , Corriveau Louise , La Flèche Marc R
Published: January 2006

The La Romaine Supracrustal Belt and the southeastern end of the Wakeham Group in the eastern Grenville Province, Canada, host a series of Pinwarian, 1.50 Ga felsic-dominated volcanic centres metamorphosed at amphibolite to granulite facies during the Grenville orogeny. The centres are interpreted as being related to the emergence of rhyolitic domes in shallow-marine intra-arc basins within the active Pinwarian continental magmatic arc. High-grade metamorphosed hydrothermal alteration zones are intimately associated with pyroclastic deposits composing these volcanic centres and an overlying composite amphibolite unit. They comprise layers of rhyolitic metatuff bearing networks of aluminous nodules and veins, migmatized garnetbiotitesillimanite gneiss with well-preserved volcanic fragments, and mottled quartzcordierite gneiss with textures similar to those of vuggy silica facies. Alteration zones of ironstone, carbonate and calc-silicate rocks, garnetite, diopsidite, epidosite, and sulphide mineralization collectively cut across the internal contacts of a composite amphibolite unit inferred to be a mafic lava and sill complex. Lithogeochemical analysis of inferred metamorphosed altered rocks and precursors highlights chemical changes typical of metamorphosed sericitic zones, advanced argillic and silicic zones, and discharge zones characterized by calcic alterations and copper mineralizations. Such zones involve the interaction of hot, very acidic to neutral fluids. Medium to heavy rare-earth elements (REE) and Zr behave as mobile elements in the hydrothermal system as a result of the presence of F-rich fluids. The chemical changes recorded by the various alteration zones share similarities with those observed in high-sulphidation, volcanic-hosted massive sulphide deposits occurring in proximal, shallow-marine, volcanic sequences.
Experimental determination of the sources of otolith carbon and associated isotopic fractionation
Authors: Solomon Christopher T , Weber Peter K , Cech, Jr. Joseph J , Ingram B Lynn , Conrad Mark E , Machavaram Madhav V , Pogodina Asya R , Franklin Rebecca L
Published: January 2006

Otolith stable carbon isotope ratios provide a unique and widely applicable environmental record. Unfortunately, uncertainty regarding the proportion of otolith carbon that derives from metabolized food versus dissolved inorganic carbon (DIC) in the water currently limits utilization of this marker. We manipulated the δ13C of food and ambient DIC in a factorial design with juvenile rainbow trout (Oncorhynchus mykiss). At the activity levels and total metabolic rates characteristic of fish in this study, 17% (±3% standard error, SE) of otolith C was metabolically derived, while >80% was derived from DIC in ambient water. We also estimated isotopic enrichment factors associated with physiological carbon transformations by measuring δ13C of blood and endolymph (which closely tracked otolith δ13C). There was substantial depletion in13C of blood relative to C sources (εbloodsources = 16.9 ± 1.1 SE), but substantial enrichment in13C in otolith relative to blood (εotoblood = 13.3 ± 1.3 SE). Net isotopic enrichment between sources and the otolith was therefore slightly negative. Most of the isotopic enrichment between the blood and the otolith was associated with the movement of C from blood to endolymph, while enrichment associated with the precipitation of otolith aragonite from the endolymph was small.
Fine-scale geographic interactions between Steller sea lion (Eumetopias jubatus) trends and local fisheries
Authors: Dillingham Peter W , Skalski John R , Ryding Kristen E
Published: January 2006

Fine-scale geographic interactions between Steller sea lion (Eumetopias jubatus) abundance trends and the abundance of local fisheries and commercial fishing efforts from Southeast Alaska to the Aleutian Islands were assessed. Census counts of Steller sea lions from 1976 to 2002 at 53 different trend sites and rookeries were grouped into 33 locales with similar population trends. Localized estimates of commercial groundfish biomass densities for walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus), arrowtooth flounder (Atheresthes stomias), and Atka mackerel (Pleurogrammus monopterygius) from 1983 to 2002 and localized estimates of commercial fishing effort from 1990 to 2002 were matched to the 33 locales. Generalized estimating equations methods found a negative relationship between Steller sea lion abundance trends and walleye pollock density (P < 0.10). However, the 4.8-fold change in walleye pollock density between 1984 and 2001 was estimated to change the rate of population change (λ) by only 0.029. The analysis estimated that elimination of all trawl fishing effort would increase λ by as little as 0.0056. Neither commercial groundfish abundance nor commercial fishing effort could explain the large historical declines in the rate of Steller sea lion population change observed.
A stochastic approach to stock reduction analysis
Authors: Walters Carl J , Martell Steven J.D. , Korman Josh
Published: January 2006

Stock reduction analysis (SRA) can complement more detailed assessment methods by using long-term historical catches to estimate recruitment rates needed to have produced those catches, yet still end up with stock sizes near those estimated by the detailed methods. A longer historical perspective can also add information to the estimation of reference points such as unfished biomass (B0) or target biomass (BMSY). Deterministic SRA models provide a single stock size trajectory that is vanishingly unlikely to have actually occurred, while stochastic SRA attempts to provide probability distributions for stock size over time under alternative hypotheses about unfished recruitment rates and about variability around assumed stockrecruitment relationships. These distributions can be generated with age-structured population models by doing large numbers of Monte Carlo simulation trials and retaining those sample trials for which the stock would not have been driven to extinction by historical catches. By resampling from these trials using likelihood weights (sampling  importance resampling method), it is possible to move into fully Bayesian, statespace assessment modeling through a series of straightforward steps and to provide understandable visualization of how much the data help to reduce uncertainty about historical fishing impacts and stock status.
Network-scale spatial and temporal variation in Chinook salmon (Oncorhynchus tshawytscha) redd distributions: patterns inferred from spatially continuous replicate surveys
Authors: Isaak Daniel J , Thurow Russell F
Published: January 2006

Spatially continuous sampling designs, when temporally replicated, provide analytical flexibility and are unmatched in their ability to provide a dynamic system view. We have compiled such a data set by georeferencing the network-scale distribution of Chinook salmon (Oncorhynchus tshawytscha) redds across a large wilderness basin (7330 km2) in central Idaho for 9 years (19952003). During this time, the population grew at a rate of 5.3 recruits per spawner, and redd numbers increased from 20 to 2271. As abundances increased, fish expanded into portions of the stream network that had recently been unoccupied. Even at the highest escapements, however, distributions remained clustered, and a limited portion of the network contained the majority of redds. The importance of the highest density spawning areas was greatest when abundances were low, suggesting these areas may serve as refugia during demographic bottlenecks. Analysis of variance indicated that redd numbers were strongly affected by local habitats and broad climatic controls, but also revealed a spacetime interaction that suggested temporal instability in spatial patterns. Our results emphasize the importance of maintaining habitats with high densities of individuals, but also suggest that broader views may be needed to accommodate the dynamics of natural salmonid populations.
Timing and determination of potential fecundity in Atlantic cod (Gadus morhua)
Authors: Skjæraasen Jon Egil , Nilsen Trygve , Kjesbu Olav S
Published: January 2006

Studies using annual averages of lipid storage or estimated quality of the feeding season have shown that energy reserves influence egg production in Atlantic cod (Gadus morhua). However, vitellogenesis starts months before spawning. Therefore, energy reserves near the start of vitellogenesis might provide better proxies of fecundity and hence egg production than yearly averages. If so, proxies with large temporal variations (e.g., weight and lipid energy) should vary similarly in their predictive power, and females with different spawning periods should have their fecundity determined at different times. We exposed cod to two photoperiods to induce different spawning seasons. Growth before spawning was monitored, and potential fecundity was measured at the onset of spawning. The date yielding the greatest explanatory power differed between photoperiods. As proxies, length varied less and had lower explanatory power than weight. Lipid energy at the onset of spawning was a poor proxy. The greatest explanatory power was found ~34 months before spawning around the start of vitellogenesis, indicating that potential fecundity was highly influenced by female energy reserves at this time. Determination of potential fecundity early in vitellogenesis may be a common feature for determinate teleost spawners.