bluuebunny/crossref_metadata_2025 huggingface dataset:
The ProtozoanNeospora caninumDirectly Triggers Bovine NK Cells To Produce Gamma Interferon and To Kill Infected Fibroblasts
Authors: Boysen Preben , Klevar Siv , Olsen Ingrid , Storset Anne K.
Published: January 2006

Natural killer (NK) cells are considered to be key players in the early innate responses to protozoan infections, primarily indirectly by producing gamma interferon (IFN-γ) in response to cytokines, like interleukin 12 (IL-12). We demonstrate that live, as well as heat-inactivated, tachyzoites ofNeospora caninum, aToxoplasma-like protozoan, directly trigger production of IFN-γ from purified, IL-2-activated bovine NK cells. This response occurred independently of IL-12 but was increased by the addition of the cytokine. A similar IFN-γ response was measured in cocultures of NK cells andN. caninum-infected autologous fibroblasts. However, no NK cell-derived IFN-γ response was detected when cells were cultured with soluble antigens from the organism, indicating that intact tachyzoites or nonsoluble components are necessary for NK cell triggering. Furthermore,N. caninum-infected autologous fibroblasts had increased susceptibility to NK cell cytotoxicity compared to uninfected fibroblasts. This cytotoxicity was largely mediated by a perforin-mediated mechanism. The activating receptor NKp46 was involved in cytotoxicity against fibroblasts but could not explain the increased cytotoxicity against infected targets. Interestingly,N. caninumtachyzoites were able to infect cultured NK cells, in which tachyzoites proliferated inside parasitophorous vacuoles. Together, these findings underscore the role of NK cells as primary responders during a protozoan infection, describe intracellular protozoan infection of NK cells in vitro for the first time, and represent the first functional study of purified bovine NK cells in response to infection.
Comparative Safety and Immunogenicity of Two Attenuated Enterotoxigenic
Escherichia coli
Vaccine Strains in Healthy Adults
Authors: McKenzie Robin , Bourgeois A. Louis , Engstrom Fayette , Hall Eric , Chang H. Sunny , Gomes Joseph G. , Kyle Jennifer L. , Cassels Fred , Turner Arthur K. , Randall Roger , Darsley Michael , Lee Cynthia , Bedford Philip , Shimko Janet , Sack David A.
Published: January 2006

A vaccine against enterotoxigenic
Escherichia coli
(ETEC) is needed to prevent diarrheal illness among children in developing countries and at-risk travelers. Two live attenuated ETEC strains, PTL002 and PTL003, which express the ETEC colonization factor CFA/II, were evaluated for safety and immunogenicity. In a randomized, double-blind, placebo-controlled trial, 19 subjects ingested one dose, and 21 subjects ingested two doses (days 0 and 10) of PTL-002 or PTL-003 at 2 × 10
9
CFU/dose. Anti-CFA/II mucosal immune responses were determined from the number of antibody-secreting cells (ASC) in blood measured by enzyme-linked immunospot assay, the antibody in lymphocyte supernatants (ALS) measured by enzyme-linked immunosorbent assay (ELISA), and fecal immunoglobulin A (IgA) levels determined by ELISA. Time-resolved fluorescence (TRF) ELISA was more sensitive than standard colorimetric ELISA for measuring serum antibody responses to CFA/II and its components, CS1 and CS3. Both constructs were well tolerated. Mild diarrhea occurred after 2 of 31 doses (6%) of PTL-003. PTL-003 produced more sustained intestinal colonization than PTL-002 and better IgA response rates: 90% versus 55% (
P
= 0.01) for anti-CFA/II IgA-ASCs, 55% versus 30% (
P
= 0.11) for serum anti-CS1 IgA by TRF, and 65% versus 25% (
P
= 0.03) for serum anti-CS3 IgA by TRF. Serum IgG response rates to CS1 or CS3 were 55% in PTL-003 recipients and 15% in PTL-002 recipients (
P
 = 0.02). Two doses of either strain were not significantly more immunogenic than one. Based on its superior immunogenicity, which was comparable to that of a virulent ETEC strain and other ETEC vaccine candidates, PTL-003 will be developed further as a component of a live, oral attenuated ETEC vaccine.
Effect of lower limb massage on electromyography and force production of the knee extensors
Authors: Hunter A M , Watt J M , Watt V , Galloway S D R
Published: January 2006

Objective:To evaluate the effect of massage on force production and neuromuscular recruitment.

Methods:Ten healthy male subjects performed isokinetic concentric contractions on the knee extensors at speeds of 60, 120, 180, and 240°/s. These contractions were performed before and after a 30 minute intervention of either rest in the supine position or lower limb massage. Electromyography (EMG) and force data were captured during the contractions.

Results:The change in isokinetic mean force due to the intervention showed a significant decrease (p<0.05) at 60°/s and a trend for a decrease (p  =  0.08) at 120°/s as a result of massage compared with passive rest. However, there were no corresponding differences in any of the EMG data. A reduction in force production was shown at 60°/s with no corresponding alteration in neuromuscular activity.

Conclusions:The results suggests that motor unit recruitment and muscle fibre conduction velocity are not responsible for the observed reductions in force. Although experimental confirmation is necessary, a possible explanation is that massage induced force loss by influencing “muscle architecture”. However, it is possible that the differences were only found at 60°/s because it was the first contraction after massage. Therefore muscle tension and architecture after massage and the duration of any massage effect need to be examined.
Live high-train low associated with increased haemoglobin mass as preparation for the 2003 World Championships in two native European world class runners
Authors: Wehrlin J P , Marti B
Published: January 2006

Background:It is unclear whether world class endurance athletes, in contrast with less well trained subjects, increase their haemoglobin mass on a regimen of living high and training low (LHTL).

Objective:To assess whether haemoglobin mass increases in world class athletes on LHTL and whether this increase is associated with peak performance at a subsequent important competition.

Methods:Two Swiss world class runners (one 5000 m and one marathon) lived for 26 days (18 hours a day) at an altitude of 2456 m and trained at 1800 m. This LHTL camp was the preparation for the World Athletic Championships taking place 27–29 days after the end of the camp. Haemoglobin mass and other haematological variables were measured before and after the LHTL camp. The performance parameter was the race times during that period.

Results:Haemoglobin mass increased by 3.9% and 7.6%, and erythrocyte volume by 5.8% and 6.3%. The race times, as well as the ranking at the World Championships, indicated clearly improved performance after the LHTL camp.

Conclusions:The results suggest that LHTL with an adequate dose of hypoxia can increase haemoglobin mass even in world class athletes, which may translate into improved performance at important competitions at sea level.
Growth hormone 1 (GH1) gene and performance and post-race rectal temperature during the South African Ironman triathlon
Authors: Walpole B , Noakes T D , Collins M
Published: January 2006

Background:Some studies have suggested that the insertion allele of theACEgene is associated with endurance performance, including the Ironman triathlon. It is possible that this association is due to genetic linkage between theACEI/D locus and the T/A variant in intron 4 of the neighbouringGH1gene. The A variant is associated with lower levels of growth hormone production. Growth hormone has multiple effects, especially on metabolism during exercise and recovery from exercise. Its production during exercise has also been shown to stimulate sweat rate and heat loss.

Objective:To determine whether theGH1gene is associated with the performance and/or post-race rectal temperatures of competitors in the South African Ironman triathlon.

Methods:A total of 169 of the fastest finishing white male triathletes who completed the 2000 and/or 2001 South African Ironman triathlon and 155 control subjects were genotyped for the T/A variant in theGH1gene. Post-race rectal temperature was also determined in 103 of these triathletes.

Results:There was no significant difference in the frequency of this polymorphism in theGH1gene when the fastest finishing triathletes were compared with the control subjects. Post-race rectal temperatures were, however, significantly higher in those triathletes with an AA genotype (mean (SD) 37.7 (0.8)°C) compared with those with a TT genotype (37.2 (0.8)°C) (p  =  0.019).

Conclusions:The T/A polymorphism in intron 4 of theGH1gene was not associated with performance of the fastest finishers of the South African Ironman triathlon. Post-race rectal temperatures were, however, significantly higher in the fastest finishing athletes, who were homozygous for aGH1genotype associated with lower growth hormone production.
High risk of new knee injury in elite footballers with previous anterior cruciate ligament injury
Authors: Waldén M , Hägglund M , Ekstrand J
Published: January 2006

Background:Anterior cruciate ligament (ACL) injury is a severe event for a footballer, but it is unclear if the knee injury rate is higher on returning to football after ACL injury.

Objective:To study the risk of knee injury in elite footballers with a history of ACL injury compared with those without.

Method:The Swedish male professional league (310 players) was studied during 2001. Players with a history of ACL injury at the study start were identified. Exposure to football and all time loss injuries during the season were recorded prospectively.

Results:Twenty four players (8%) had a history of 28 ACL injuries in 27 knees (one rerupture). These players had a higher incidence of new knee injury of any type than the players without ACL injury (mean (SD) 4.2 (3.7)v1.0 (0.7) injuries per 1000 hours, p  =  0.02). The risk of suffering a knee overuse injury was significantly higher regardless of whether the player (relative risk 4.8, 95% confidence interval 2.0 to 11.2) or the knee (relative risk 7.9, 95% confidence interval 3.4 to 18.5) was used as the unit of analysis. No interactive effects of age or any other anthropometric data were seen.

Conclusion:The risk of new knee injury, especially overuse injury, was significantly increased on return to elite football after ACL injury regardless of whether the player or the knee was used as the unit of analysis.
No holds barred sport fighting: a 10 year review of mixed martial arts competition
Authors: Buse G J
Published: January 2006

Objective:To identify the most salient medical issues that may be associated with mixed martial arts competition by determining the types and proportions of match stoppages.

Methods:Publicly available video footage of 1284 men competing in 642 consecutive televised matches from November 1993 to November 2003 was reviewed to determine the reasons for which matches were stopped. Matches were sanctioned by either a United States or Japan based mixed martial arts organisation.

Results:Of the 642 matches, 182 (28.3±3.4%) were stopped because of head impact, 106 (16.5±2.9%) because of musculoskeletal stress, 91 (14.1±2.7%) because of neck choke, 83 (12.9±2.6%) because of miscellaneous trauma, 173 (27.0±3.4%) because of expiration of match time, and seven (1.0±0.8%) because of disqualification, where the values in parentheses are percentages±95% confidence interval.

Conclusions:Blunt force to the head resulted in the highest proportion of match stoppages. Further research is warranted to delineate the morbidity associated with participation in mixed martial arts.
Thermoregulatory observations in soccer match play: professional and recreational level applications using an intestinal pill system to measure core temperature
Authors: Edwards A M , Clark N A
Published: January 2006

Background:Technological limitations associated with oesophageal and rectal temperature probes have previously limited match play observations of body temperature.

Objective:To investigate the application of an intestinal pill system to measure core temperature during dynamic, field based, soccer matches.

Methods:Core temperature (Tc) was assessed using the intestinal pill system (CorTemp 2000) and changes in plasma volume were calculated using the values for haemoglobin and packed cell volume obtained before and after recreational (n = 8) and the professional soccer (n = 7) matches.

Results:In the recreational match, there were significant post-match reductions in body mass (−1.6%, p<0.05) and plasma volume (−7.2%, p<0.01). Significant increases were observed inTcfrom rest to half time (p<0.01) and from half time to full time (p<0.05). In the professional match, body mass decreased by 1.9% (p<0.05) and plasma volume by 11.6% (p<0.01).Tcincreased from rest to half time (p<0.01) but was unchanged from half time to full time. Significant associations were observed between maximum oxygen consumption and match play heart rates in the second half of each match but these were not related to changes in plasma volume orTc.

Conclusions:Intestinal temperature proved a useful method of recording core temperature during soccer match play and assisted in the measurement of alterations in thermoregulatory variables in response to both professional and recreational level soccer matches; however, technological limitations still restrict the wider application of this method, especially at a competitive level.
Dose–response relation between physical activity and sick leave
Authors: Proper K I , van den Heuvel S G , De Vroome E M , Hildebrandt V H , Van der Beek A J
Published: January 2006

Objective:To investigate the dose–response relation between moderate and vigorous physical activity and sick leave in a working population.

Methods:Data were used from three large Dutch databases: two continuous, cross sectional surveys among a representative sample of the Dutch population and one prospective cohort study. A distinction was made between duration, frequency and intensity of physical activity. The outcome measure was the number of days of sick leave. Analyses of variance were used to compare sick leave (in days) for workers with different amounts of physical activity, in particular workers meeting the physical activity recommendationsvthose who did not. Linear and logistic regression analyses were used to obtain effect estimates in the prospective cohort study, with the generalised estimating equation (GEE) method.

Results:No relation was found between moderate physical activity and sick leave. In two databases, workers meeting the recommendation of vigorous physical activity (active at a vigorous level for at least three times a week) had significantly less sick leave: more than one day over two months and more than four days over a year. The duration of vigorous physical activity was not associated with sick leave.

Conclusion:Physical activity at a vigorous intensity level for at least three times a week, as in the CDC/ACSM recommendation, has a positive effect on sick leave.
Nature as a theme in Canadian literature
Authors: Turner Kate , Freedman Bill
Published: January 2006

The relationships of people with the natural world are expressed in diverse ways, including painting, photographs, sculpture, song, video, and literature. In this document, we review historical and contemporary portrayals of nature as a theme in Canadian literature. Our assessment is intended to explore how Canadians have articulated their feelings about nature through literary expression, and to thereby gain insight into their empathy for natural ecosystems and native species, and their concern about damage caused to those values. We begin with a broad overview of nature as a theme in cultural expression, including overarching ones in Canadian literature, and discuss the influential literary views of Northrop Frye, Margaret Atwood, and their critics. We then examine the expression of nature within seven focal areas: early aboriginal expression, narratives of explorers, stories of settlers, the genre of animal stories, 20th-century poetry, recent aboriginal literature, and environmental ideas in contemporary prose. We identify six dominant themes of the expression of nature in Canadian literature: (1) humans as a part of nature; (2) a bounty of natural resources; (3) fear of an adversarial wilderness; (4) improvement of nature; (5) regret of environmental damage and perhaps despair of the future; and (6) love and respect of species and natural landscapes. Finally, we discuss how nature as a theme embedded in Canadian literature can be harnessed to further the compelling objectives of environmental literacy by providing sympathetic insights into the relationships of people and society with the species and ecosystems with which they share Canada.Key words: nature, literature, culture, Canada, environmental literacy.
Habitat preference of the epiphyteTillandsia recurvata(Bromeliaceae) in a semi-desert environment in Central Mexico
Authors: Bernal Rocío , Valverde Teresa , Hernández-Rosas Laura
Published: January 2006

Tillandsia recurvata L. is an atmospheric epiphyte that occupies tree canopies in many parts of tropical America. We investigated the host preferences of this species by analyzing its occurrence on trees in a 1-ha plot in a semi-desert environment in Mexico. Additionally, we carried out germination experiments and recorded seedling survival and growth in different microsites on the three preferred host species. Our results indicate that T. recurvata occupies the crowns of certain host species (Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C. Harms, Acacia bilimekii Macbr., and Cercidium praecox (Ruiz & Pav.) Harms) with a higher frequency than expected by chance. In addition to species identity, tree size affected the probability of being occupied: small trees were occupied with lower frequencies and with lower densities than larger ones. On the other hand, distance to the nearest colonized tree was not related to the probability of a tree being occupied. Seed germination ranged from 0% to 7.5% and did not differ among the three host species tested. However, both seed germination and seedling growth were higher in the outer and upper parts of tree crowns. Given the patchy distribution of this epiphyte, we propose this system may be viewed as a metapopulation in which patch suitability varies according to host identity and size.
A newly described plant disease complex involving two distinct viruses in a native Alaskan lily,Streptopus amplexifolius
Authors: Robertson N.L.
Published: January 2006

The etiology of a previously unknown disease of Streptopus amplexifolius (L.) DC. (twisted stalk) that occurred in south central Alaska was elucidated. Symptomatic plants with yellow-green dashes and streaks on their leaves contained distinct viruses belonging to the family Potyviridae and (or) tentatively to the family Flexiviridae genus Carlavirus . Each virus’ identity was confirmed by a combination of morphology, serology (ELISA and (or) Western analysis), and sequences obtained from reverse transcriptase – polymerase chain reaction products previously generated by potyvirus- or carlavirus-specific primers. The mechanical transmission of particles (purified from twisted stalk as a mixture of both viruses or as a single preparation of each virus) to S. amplexifolius, Chenopodium amaranticolor Coste et Reyn, and Chenopodium quinoa Willd., fulfilled Koch’s postulates. The relatively high incidence of infected plants and associated severe symptoms in populations from several sites in south central Alaska gave evidence that native plants are susceptible to, and are adversely affected by viral diseases. Even though Streptopus species grow throughout the temperate regions of the world, this is the first report of a pathogen(s) infecting plants in the genus Streptopus.
Opium poppy: a model system to investigate alkaloid biosynthesis in plants
Authors: Facchini Peter J. , Bird David A. , Bourgault Richard , Hagel Jillian M. , Liscombe David K. , MacLeod Benjamin P. , Zulak Katherine G.
Published: January 2006

Remarkable progress on the biology of plant secondary metabolism has recently been realized. The application of advanced biochemistry, molecular, cellular, and genomic methodologies has revealed biological paradigms unique to the biosynthesis of secondary metabolites, including alkaloids, flavonoids, glucosinolates, phenylpropanoids, and terpenoids. The use of model plant systems has facilitated integrative research on the biosynthesis and regulation of each group of natural products. The model legume, Medicago truncatula Gaertn., plays a key role in studies on phenylpropanoid and flavonoid metabolism. Mint ( Mentha × piperita L.) and various conifers are the systems of choice to investigate terpenoid metabolism, whereas members of the mustard family (Brassica spp.) are central to work on glucosinolate pathways. Arabidopsis thaliana (L.) Heynh. is also used to study the biosynthesis of most secondary compounds, except alkaloids. Unlike other categories of secondary metabolites, the many structural types of alkaloids are biosynthetically unrelated. The biology of each group is unique, although common paradigms are also apparent. Opium poppy ( Papaver somniferum L.) produces a large number of benzylisoquinoline alkaloids and has begun to challenge Madigascar periwinkle ( Catharanthus roseus (L.) G. Don), which accumulates monoterpenoid indole alkaloids, as the most versatile model system to study alkaloid metabolism. An overview of recent progress on the biology of plant alkaloid biosynthesis, with a focus on benzylisoquinoline alkaloid pathways in opium poppy and related species, highlights the emergence of opium poppy as an important model system to investigate secondary metabolism.
Diurnal cycle of sparteine production in Lupinus arcticus
Authors: Sharam Gregory J. , Turkington Roy
Published: January 2006

Sparteine is a neurological toxin found in arctic lupine ( Lupinus arcticus S. Wats.) and is probably used as a defensive chemical to deter herbivory, particularly by snowshoe hares ( Lepus americanus Erxleben). Lupine leaves were collected in southwestern Yukon at 2 h intervals for 2 consecutive days at the peak of the growing season (24–25 June), and their sparteine was extracted and compared with a standard using gas chromatography. A significant daily cycle of sparteine in leaf material was observed, with maximum concentrations occurring during the night and minimum during the afternoon. This may be a temporally optimal response to higher levels of hare herbivory that occur at night.
Phenology of Psychotria tenuinervis (Rubiaceae) in Atlantic forest fragments: fragment and habitat scales
Authors: Ramos Flavio Nunes , Santos Flavio A. Maës
Published: January 2006

The objective of this study was to investigate (1) whether the reproductive phenology of Psychotria tenuinervis Muell. Arg. is influenced by climatic conditions (precipitation and temperature); (2) whether there are differences in the reproductive phenology of P. tenuinervis between fragments (fragment scale); and (3) whether there are differences in the reproductive phenology of P. tenuinervis among anthropogenic edges, natural edges, and in the forest interior within a fragment (habitat scale). The patterns of flowering and fruiting found in 2002 and 2003 were similar between forest fragments, and proximate factors were not very important in determining the reproductive phenology of P. tenuinervis. There was phenological similarity among the three habitats on a habitat scale, probably because of the extensive heterogeneity within each habitat, with the percentage of flowering and fruiting individuals and the intensity and duration of these phenophases varying among the sample plots. This high variability within habitats indicated that factors other than the distance from the edges (i.e., gaps, matrix composition, and edge age) probably had a greater influence on the reproductive phenology of P. tenuinervis. These results also indicate that heterogeneity within fragmented habitats needs to be considered in conservation and management programs for fragmented landscapes.
Ultrastructure of sporodochium and conidium development in the anamorphic fungus Epicoccum nigrum
Authors: Mims C.W. , Richardson E.A.
Published: January 2006

Scanning and transmission electron microscopy were used to examine sporodochium and conidium development in Epicoccum nigrum Link. Each sporodochium, a slightly raised mass of hyphae consisting of a pseudoparenchymous stroma covered with muriform conidia, arose from a group of loosely packed hyphae that formed on the agar surface. Conidiophores developed from the surface of the stroma. Each possessed a two-layered wall consisting of an inner electron transparent layer and an outer electron dense layer. Most conidiophores consisted of only two cells, the apical of which became swollen and gave rise to a solitary conidium initial in a holoblastic fashion. This initial enlarged and became divided into a smaller basal cell and a larger apical cell by a transverse septum. While the basal cell did not divide further, the apical cell became divided into numerous cells as the result of the formation of longitudinal and transverse septa. As a conidium matured the electron transparent inner layer of its wall thickened while the surface of its electron dense outer wall layer became transformed into small wart-like surface ornaments. Conidium secession was schizolytic and involved a transverse splitting of the septum separating the basal cell of a conidium from its conidiophore. The end of the basal cell and the tip of the conidiophore became rounded off during conidium secession.
Iron oxide - copper - gold-type and related deposits in the Manitou Lake area, eastern Grenville Province, Quebec: variations in setting, composition, and style
Authors: Clark T , Gobeil A , David J
Published: January 2006

The Manitou Lake area (Kwyjibo and Lac Marmont sectors), located in Quebec's eastern Grenville Province, contains magnetite-rich deposits with variable morphological, mineralogical, and chemical characteristics. Most Kwyjibo sector deposits are rich in Cu, rare-earth elements (REE), Y, P, F, and Ag and are anomalous in Th, U, Mo, W, Zr, and Au, and Lac Marmont sector deposits are commonly poor in these elements. Deposits occur in or are closely associated with 11751168 Ma leucogranite. They contain combinations of magnetite, clinopyroxene, bluegreen hornblende, titanite, apatite, fluorite, quartz, biotite, andradite, epidote, albite, hematite, sulfides (chalcopyrite, pyrite, pyrrhotite, molybdenite, sphalerite), ilmenite, allanite, and other REE-bearing minerals. Veins and breccias are common. Most of the magnetite mineralization was preceded by potassic metasomatism (microcline) and was followed by most of the sulfides and radioactive minerals. Nearby sulfide-dominant deposits may be related. The deposits were formed by metasomatic replacement and fracture filling from hydrothermal fluids of variable composition, which were probably channeled in major, active faults. Oxygen-isotope data from magnetite-rich rocks suggest that fluids were predominantly magmatic and (or) metamorphic and that, locally, mixing with cooler meteoric water may have facilitated precipitation of sulfides and rare-metal minerals. Titanites in mineralized rock have been dated at 972 ± 5 Ma, but most magnetite may be older. Mineralization was syn- to post-tectonic and occurred in an orogenic to orogenic-collapse setting. The CuREEY-rich deposits are similar to iron oxide  copper  gold (IOCG) Olympic Dam type deposits, and copper- and rare-metals-poor occurrences resemble magnetite ± apatite Kiruna-type deposits.
Multiple hydroclimatic controls over recent sedimentation in proglacial Mirror Lake, southern Selwyn Mountains, Northwest Territories
Authors: Tomkins Jessica D , Lamoureux Scott F
Published: January 2006

Varves from Mirror Lake, Northwest Territories (62°N, 128°W) reveal significant, but changing climatic influences on discharge and sedimentation on a decadal scale during the late 20th century. The complex hydroclimatic signal within the sediments indicates the difficulty in identifying a quantitative relationship between varve thickness and a single climatic variable. Regression of recent varve thickness with local meteorological data shows July temperature as the dominant control over sediment accumulation. In contrast, the dampening effects of increased snowfall on glacier ablation and resultant runoff reduce sediment delivery. Although the impact of snowfall does not appear to significantly weaken the relationship between summer temperature and varve formation, periods when multiple climatic factors control sediment delivery are characterized by distinctive varves containing two prominent silt units. Thus, the Mirror Lake hydrological system appears to shift between two general states. The first state involves a pronounced summer glacial meltwater phase due to dominant summer temperature influences on glacial melt, resulting in varves with one silt unit. This varve structure dominates the sedimentary record from A.D. 1670 to 1941, possibly reflecting a Little Ice Age influence in the study area. The second state operates in years when glacial meltwater discharge is delayed until August, due to increased snow cover, and the lake receives increased sediment-poor nival melt. These conditions lead to the formation of varves with two silt units corresponding to nival and glacial discharge phases and are common in the sedimentary record from A.D. 1390 to 1669 and A.D. 1942 to 1996.
The thermal history of the Nares Strait, Kane Basin, and Smith Sound region in Canada and Greenland: constraints from apatite fission-track and (UThSm)/He dating
Authors: Grist Alexander M , Zentilli Marcos
Published: January 2006

Apatite fission-track and (UThSm)/He data for samples with ProterozoicNeogene lithologic ages from eastern Ellesmere, Devon, and Baffin islands in the Canadian Arctic Archipelago and northwest Greenland provide insights into the complex thermal history of this region. Most data reflect exhumational cooling of the region as a sediment source area for the developing Sverdrup Basin to the west during late Paleozoic  Mesozoic time. Samples proximal to the basin margin record late Paleozoic cooling consistent with erosion of uplifted rift flanks and widespread clastic sedimentation during early rifting and thermal subsidence. Data from distal samples are consistent with early Mesozoic epeirogenic denudational cooling during periods of high sediment supply from well-developed river systems. Around northern Baffin Bay, the data record erosional cooling of uplifted rift flanks in response to Late Cretaceous rifting. Rapid denudation rates are indicated for southeastern Devon Island, compatible with thick Upper Cretaceous strata offshore in Lancaster Sound. Slower denudation rates are indicated for northwest Greenland. Along Nares Strait, data reflect mafic volcanism or erosional exhumation associated with strike-slip and (or) thrust displacements during the Paleogene Eurekan orogeny and offer limited support for the existence of a Wegener fault. Fission-track ages older than those obtained in central Ellesmere Island, however, suggest that active tectonics occurred earlier near the strait, and strike-slip tectonism and deformation were likely partitioned across a relatively wide belt. Apatites obtained from Archean gneisses and Franklinian dykes have up to 500 ppm Sm, and up to 15% of the radiogenic He is Sm derived.
A long-term field study (1951-2003) of ventifacts formed by katabatic winds at Paulatuk, western Arctic coast, Canada
Authors: Mackay J Ross , Burn C R
Published: January 2006

Field measurements have been made since 1951 on hundreds of ventifacts abraded by strong, southerly, katabatic winds that blow in winter and summer past Paulatuk, a small western Arctic coastal settlement. Sand is commonly entrained by the strongest winds in winter. The ventifacts, all glacial erratics deposited prior to 12 ka BP, have been gradually rotated by the southerly winds until the long axes of most ventifacts now trend approximately eastwest, normal to the katabatic winds. In contrast, pebbles have a slightly preferred northsouth orientation, parallel to the katabatic winds. The facets on sandstone and diabase ventifacts are almost planar, but are rounded on granites and hackled on limestones, reflecting the influence of both solution and abrasion. Abrasion is evident on the built structures in Paulatuk, but despite the over 50 years of observation, abrasion of the ventifacts has been virtually undetectable. The extremely slow abrasion rate has been estimated from: observations on two ventifacts from 1951 to 2003; photographic comparisons and observations of 60 ventifacts from 1968 to 2003; optical examination of 14 granite slabs, polished and unpolished, exposed to abrasion from 1967 to 1976; and comparisons of the windward and leeward sides of six large rock caches built with ventifacts probably long before 1900. If the present rates of abrasion are representative of Holocene conditions, ventifact formation has probably taken much of postglacial time. The increase in vegetation cover around many rocks between 1968 and 2003 suggests that the climate has changed in the last three decades.
Pinwarian (1.50 Ga) volcanism and hydrothermal activity at the eastern margin of the Wakeham Group, Grenville Province, Quebec
Authors: Corriveau Louise , Bonnet Anne-Laure
Published: January 2006

Volcanic belts developed along the southeastern continental margin of Laurentia between 1.70 and 1.30 Ga and subsequently metamorphosed at high grade are today largely concealed among gneiss complexes of the Grenville Province. At the eastern end of the Wakeham Group and in the La Romaine Supracrustal Belt to the east, four 1.50 Ga volcanic centres were found among gneissic synvolcanic intrusions typical of the 1.521.46 Ga Pinwarian continental magmatic arc. Upper amphibolite- to granulite-facies rhyolitic to dacitic lavas and coarse lapillistone overlie or are intimately associated with arenites typical of the Wakeham Group. Garnetite, ironstone, carbonate rock, calc-silicate rock, and sillimanite-bearing nodules, veins, and gneiss, locally preserving lapilli, are also present. The distribution, paragenesis, and modes of most of these latter units differ from those of normal metasediments but are diagnostic of metamorphosed exhalites and hydrothermal alteration zones. In the La Romaine Supracrustal Belt, they are associated with pyroclastic horizons and a mineralized composite amphibolite unit. Volcanic textures include flow banding, wispy lapilli moulding fragmented lapilli and rounded lapilli with quartz-feldspar mosaics (filled vesicles), and in situ shattering of lapilli. These textures and the presence of advanced argillic alteration point to vesicular volcanism and hydrothermal activity in a subaerial to shallow submarine environment. Rare mafic lapilli attest to coeval mafic magmatism. The pervasive calc-alkaline signature of the eruptive and intrusive felsic to mafic rocks and their distribution are compatible with the development of 1.50 Ga intra-arc volcano-sedimentary belts stemming from the Wakeham Group basin and extending eastward within the Pinwarian continental magmatic arc.
Shoal behaviour and maturity relations of spawning capelin (Mallotus villosus) off Newfoundland: demersal spawning and diel vertical movement patterns
Authors: Davoren Gail K , Anderson John T , Montevecchi William A
Published: January 2006

We investigated shoals of capelin (Mallotus villosus), the focal forage fish species in the Northwest Atlantic, in nearshore Newfoundland during spawning (20002003). Large shoals of maturing capelin were observed in warm (>0 °C), deep (>240 m) water. Smaller shoals of maturing fish were located in two specific areas closer to shore in shallower water (100150 m). Shoals persisted in these staging areas in all years and moved into warm surface water during dark but remained in cold (<0 °C) deep water during daylight. These diel vertical movement patterns may reflect a trade-off between growth and survival, whereby cold, deep water allows reduced predation risk from visual, air-breathing predators while warm, surface water allows increased gonadal development. Shoals of spent capelin, mainly females, were also found in these areas. Sex-specific shoals were observed between staging areas and the coast. Closer to shore, mature, mixed-sex shoals revealed two previously undocumented demersal spawning sites (2833 m). Suitable habitat for spawning and staging areas resulted in persistent aggregations of capelin shoals, reflecting key foraging areas for top predators and critical areas for conservation.
Population dynamics of Japanese pink salmon (Oncorhynchus gorbuscha): are recent increases explained by hatchery programs or climatic variations?
Authors: Morita Kentaro , Morita Shoko H , Fukuwaka Masa-aki
Published: January 2006

Hatchery programs involving the mass release of artificially propagated fishes have been implemented worldwide. However, few studies have assessed whether hatchery programs actually increase the net population growth of the target species after accounting for the effects of density dependence and climatic variation. We examined the combined effects of density dependence, climatic variation, and hatchery release on the population dynamics of Japanese pink salmon (Oncorhynchus gorbuscha) from 1969 to 2003. The population trends were more closely linked to climatic factors than to the intensity of the hatchery programs. The estimated contributions of hatchery-released fry to catches during the past decade are small. We concluded that the recent catch increases of Japanese pink salmon could be largely explained by climate change, with increased hatchery releases having little effect.
Spatial evidence for information exchange and competition in the Gulf of St. Lawrence snow crab (Chionoecetes opilio) fishery
Authors: Gillis Darren M , Wade Elmer , Swain Douglas P
Published: January 2006

Throughout the 1990s, the Gulf of St. Lawrence snow crab (Chionoecetes opilio) harvest provided an example of effective co-management in a developing fishery. The Department of Fisheries and Oceans Canada (DFO) and the snow crab fleet (the fleet) shared information that coordinated management and exploitation throughout the season. A preseason survey by DFO provided resource distributions prior to the fishery's opening. In-season monitoring allowed managers to track spatial and temporal variation in crab availability. This level of detail allowed the application of the ideal free distribution as a management and conservation tool. However, proper justification for its application requires the demonstration of information exchange and competitive effects. The spatial distribution of effort suggests that both of these are present. Fishing effort was influenced by public information and potential information exchange within the fleet. Reduced aggregation at smaller spatial scales suggests competition in trap placement. Thus, increasing fleet size may have a disproportionately small impact on fishing mortality because of limitations in information exchange and the lack of personal information in the new vessels. However, the nonlinear relationship between crab abundance and catch rates suggests that managers should avoid policies that increase fishing effort during times of low crab abundance.
The effects of the endocrine disrupter 4-nonylphenol on the behaviour of juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Ward Ashley JW , Duff Alison J , Currie Suzanne
Published: January 2006

Endocrine-disrupting chemicals pose a serious threat to the health of animals, particularly those in aquatic ecosystems. One such chemical, the alkylphenolic compound 4-nonylphenol (4-NP), is used extensively as a surfactant in industrial and sewage-treatment processes and is thus extremely widespread in the aquatic environment. The impact of pollutants on organisms can be measured using a number of toxicological assays. The use of behavioural studies is one such tool, allowing a noninvasive, proximate assessment of the effects of exposure. In this study, we examined the effects of short-term exposure to 4-NP on the behaviour of juvenile female rainbow trout (Oncorhynchus mykiss). Fish that had been exposed to 4-NP over a 5-day period showed a decreased shoaling tendency, were more likely to be attacked by other fish, and were less successful when competing for food resources than control fish. Focal fish that had been exposed to 4-NP showed no decrease in swimming speed or response to a simulated predator strike compared with control fish. We discuss possible reasons for these changes in social behaviour.
Chutes and ladders and other games we play with rivers. II. Simulated effects of translocation on white sturgeon
Authors: Jager Henriette I
Published: January 2006

Restoring connectivity is viewed as an important recovery option for fish species adversely affected by river fragmentation. This simulation study quantified the genetic and demographic effects of translocation on metapopulations of white sturgeon (Acipenser transmontanus) inhabiting a series of long (source) and short (sink) river segments. Genetic effects were predictable; upstream translocations increased introgression and downstream translocations had no effect. Demographic results suggest that indiscriminant efforts to reconnect populations may do more harm than good. Simulated river systems with high interspersion of long and short segments and a long segment far upstream tended to benefit most from translocation, but only when narrow screening or downstream passage was also provided below the river segment receiving fish. When combined with narrow screening, upstream translocation to a long segment subsidizing several downstream short segments produced the best results. Downstream passage outperformed narrow screening only when the translocation recipient was a short segment in a river system with low interspersion and no long, upstream river segment. This model-based evaluation of reconnection options has helped to refine ideas about restoring populations in fragmented rivers by predicting which options benefit riverine metapopulations as a whole.
Variation of agonistic behavior among juvenile Chinook salmon (Oncorhynchus tshawytscha) of hatchery, hybrid, and wild origin
Authors: Wessel Maria Lang , Smoker William W , Fagen Robert M , Joyce John
Published: January 2006

Agonistic behavior and ability to dominate were compared among juveniles from a hatchery stock of Chinook salmon (Oncorhynchus tshawytscha) that has experienced five generations of hatchery culture, juveniles derived from the wild founding stock but produced from parents cultured in the same hatchery environment as the hatchery stock, and second-generation hybrids between the two lines. Equal numbers of parr (18) from equal numbers of families (5) from each fish line (3) were tested, and all lines were raised in a similar hatchery environment. During 20 min of observation in replicate artificial stream tanks, hatchery-derived fish made significantly greater numbers of charges, displays, and nips than wild-derived fish. Hybrids also made significantly greater numbers of charges, displays, and nips than wild-derived fish but significantly fewer displays than hatchery-derived fish. No difference was detected in the ability of fish lines to win dyadic dominance contests. These results suggest that the differences detected are genetic in origin and are consistent with divergence of the hatchery stock from the founding wild stock.
Effects of different ligands on the bioaccumulation and subsequent depuration of dietary Cu and Zn in juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Kjoss Victoria A , Wood Chris M , McDonald D Gordon
Published: January 2006

The effects of different ligands on the bioavailability of dietary copper (Cu) and zinc (Zn) to fish have not been thoroughly investigated. We therefore exposed juvenile rainbow trout (Oncorhynchus mykiss; ~200 mg body weight) to control food or to food supplemented with different Cu (~400 µg·g1food) or Zn (~1000 µg·g1food) compounds. Tissue metal accumulation was compared among groups. Fish fed CuO showed no differences in tissue Cu concentrations relative to control fish, suggesting that Cu was not readily available for uptake in this form. In contrast, Cu in the form of CuSO4, Cu-proteinate, or Cu-lysine was much more available for uptake, resulting in substantial increases in liver, gut tissue, and whole-body Cu concentrations during the loading phase and decreases during depuration, although liver and whole-body levels remained elevated after 2 weeks. We found no differences in tissue Cu accumulation among these three complexes. There were no effects on growth. For Zn, we found no differences among any of the treatments, including controls, in Zn accumulation or growth. Overall, there was homeostasis of whole-body and tissue-specific Zn concentrations despite the large differences in dietary Zn loads.
Pore-water pressure and water volume change of an unsaturated soil under infiltration conditions
Authors: Meilani Inge , Rahardjo Harianto , Leong Eng-Choon
Published: January 2006

Triaxial shearinginfiltration tests were conducted to study the pore-water pressure and volume change of unsaturated soils subjected to infiltration conditions. A modified triaxial apparatus with three Nanyang Technological University (NTU) mini suction probes along the specimen height was used for the experimental program. Elastic moduli were obtained for the soil structure with respect to changes in net confining pressure (E) and matric suction (H). Water volumetric moduli associated with changes in net confining pressure (Ew) and matric suction (Hw) were also obtained from the shearinginfiltration tests. Water volumetric strain and pore-water pressure during the shearinginfiltration tests were computed based on volume change theory. This paper presents the significance of obtaining the parameter Hwfrom an appropriate scanning curve of a soil-water characteristic curve (SWCC) for the computation of water volumetric strain and pore-water pressure changes during a shearinginfiltration test. The appropriate scanning curve should be obtained from the wetting curve of the SWCC at the matric suction where the infiltration test commences.Key words: infiltration, matric suction, triaxial, unsaturated soils, pore-water pressure, water volume change.
Variations in moisture content for a soil cover over a 10 year period
Authors: Weeks Björn , Wilson G Ward
Published: January 2006

The Equity Silver mine is located in north-central British Columbia and is the site of a large, well-instrumented soil cover. The soil-cover site was designed to prevent the generation of acid rock drainage from the acid-generating waste rock disposed of at this site. The cover was designed to act as an oxygen barrier by maintaining a layer of saturated soil above the waste rock. The cover consists of a compacted till placed over the waste rock and covered with a non-compacted layer of the same material. Neutron probes and thermal conductivity sensors were used to monitor the moisture content of the cover soil over a 10 year period. Weather data at the site were also collected. A review of the data collected has shown that saturation was maintained in the lower, 0.5 m thick compacted layer of the cover, as per the original cover design. The upper cover layer (0.3 m of noncompacted till) was subject to seasonal variations in moisture content, with drying in the summer months and wetting in the fall and spring. Variations in the moisture of the upper layer correlated well with the weather data collected at the site. Spatial variations were noted in the water contents measured over the cover, but a nearly saturated lower layer appears to have been maintained throughout the area monitored.Key words: soil cover, neutron probes, moisture profile, mine waste covers.