bluuebunny/crossref_metadata_2025 huggingface dataset:
Sediment yields from unit‐source semiarid watersheds at Walnut Gulch
Authors: Nearing M. A. , Nichols M. H. , Stone J. J. , Renard K. G. , Simanton J. R.
Published: June 2007

This study reports sediment yields from seven small (0.18–5.42 ha) watersheds in Southern Arizona measured from 1995 to 2005. Sediment concentrations and total event sediment yields were related to storm‐runoff characteristics, and statistical relationships were developed to estimate sediment yields for events with missing data. Precipitation ranged from 263 to 298 mm yr−1, runoff ranged from 8.2 to 26.4 mm yr−1, and sediment yields ranged from 0.07 to 5.7 t ha−1 yr−1, with an areal average of 2.2 t ha−1 yr−1. For six of the seven watersheds, between 6 and 10 events produced 50% of the total sediment yields over the 11‐year period. On the seventh watershed, two storms produced 66% of the sediment because of differences in the geomorphology and vegetation characteristics of that area. Differences between sediment yields from all watersheds were attributable to instrumentation, watershed morphology, degree of channel incision, and vegetation.
Increased groundwater to stream discharge from permafrost thawing in the Yukon River basin: Potential impacts on lateral export of carbon and nitrogen
Authors: Walvoord Michelle A. , Striegl Robert G.
Published: June 2007

Arctic and subarctic watersheds are undergoing climate warming, permafrost thawing, and thermokarst formation resulting in quantitative shifts in surface water –groundwater interaction at the basin scale. Groundwater currently comprises almost one fourth of Yukon River water discharged to the Bering Sea and contributes 5–10% of the dissolved organic carbon (DOC) and nitrogen (DON) and 35–45% of the dissolved inorganic carbon (DIC) and nitrogen (DIN) loads. Long‐term streamflow records (>30 yrs) of the Yukon River basin indicate a general upward trend in groundwater contribution to streamflow of 0.7–0.9%/yr and no pervasive change in annual flow. We propose that the increases in groundwater contributions were caused predominately by climate warming and permafrost thawing that enhances infiltration and supports deeper flowpaths. The increased groundwater fraction may result in decreased DOC and DON and increased DIC and DIN export when annual flow remains unchanged.
Lack of bipolar see‐saw in response to Southern Ocean wind reduction
Authors: Levermann A. , Schewe J. , Montoya M.
Published: June 2007

A cessation of the Atlantic meridional overturning circulation (AMOC) significantly reduces northward oceanic heat transport. In response to anomalous freshwater flux, this leads to the classic ‘bipolar see‐saw’ pattern of northern cooling and southern warming in surface air and ocean temperatures. By contrast, as shown here in a coupled climate model, both northern and southern cooling are observed for an AMOC reduction in response to reduced wind stress in the Southern Ocean (SO). For very weak SO wind stress, not only the overturning circulation collapses, but sea ice export from the SO is strongly reduced. Consequently, sea ice extent and albedo increase in this region. The resulting cooling overcompensates the warming by the reduced northward heat transport. The effect depends continuously on changes in wind stress and is reversed for increased winds. It may have consequences for abrupt climate change, the last deglaciation and climate sensitivity to increasing atmospheric CO2 concentration.
Emotion and Rationality: A Critical Review and Interpretation of Empirical Evidence
Authors: Pham Michel Tuan
Published: June 2007

The relation between emotion and rationality is assessed by reviewing empirical findings from multiple disciplines. Two types of emotional phenomena are examined—incidental emotional states and integral emotional responses—and three conceptions of rationality are considered—logical, material, and ecological. Emotional states influence reasoning processes, are often misattributed to focal objects, distort beliefs in an assimilative fashion, disrupt self-control when intensely negative, but do not necessarily increase risk-taking. Integral emotional responses are often used as proxies for values, and valuations based on these responses exhibit distinct properties: efficiency, consistency, polarization, myopia, scale- insensitivity, and reference-dependence. Emotions seem to promote social and moral behavior. Conjectures about the design features of the affective system that give rise to seeming sources of rationality or irrationality are proposed. It is concluded that any categorical statement about the overall rationality or irrationality of emotion would be misleading.
Computed Tomography Assessment of Cerebral Perfusion Using a Distributed Parameter Tracer Kinetics Model: Validation with H2(15)O Positron Emission Tomography Measurements and Initial Clinical Experience in Patients with Acute Stroke
Authors: Bisdas Sotirios , Donnerstag Frank , Berding Georg , Vogl Thomas J , Thng Choon Hua , Koh Tong San
Published: June 2007

We describe a distributed parameter (DP) model for tracer kinetic analysis in brain and validate the derived perfusion values with positron emission tomography (PET) scans. The proposed model is applied on actual clinical cases of hemispheric stroke. Nine patients with experienced transient ischaemic attack or minor stroke and a stenosis of the internal carotid artery were referred for computed tomography (CT) and PET imaging. The applicability of the DP model in clinical practice was tested in seven patients with acute stroke who received a baseline perfusion CT study and a noncontrast follow-up CT study after 2.4 ± 1.8 days. The mean blood flow ( F) value for all patients with carotid stenosis in the pooled data (54 regions of interest (ROIs)) was 37.9 ± 11.2 mL/min per 100 g in perfusion CT and 35.6 ± 9.8 mL/min per 100 g in perfusion PET imaging [ r = 0.77 ( P = 0.00)]. Regression analysis of the pooled ROIs for every patient revealed significant correlation between F values in seven patients [ r = 0.50 to 0.79 ( r2-values ranged from 0.45 to 0.79), (0.01 ≤ P ≤ 0.05)]. Parametric maps that corresponded to all physiologic parameters were generated for every perfusion CT in the patients with acute stroke using the DP model. The ischaemic area was better delineated in F, intravascular blood volume and lag time ( tlag) maps. The correlation coefficient comparing the visually outlined regions of abnormality between the tlag parametric map and the follow-up CT scans was 0.81 ( P = 0.003). In conclusion, DP physiological model using more realistic pharmacokinetics is feasible in dynamic contrast-enhanced CT of the brain in patients with acute and chronic cerebrovascular disease.
Larval morphology of the diving beetle Celina and the phylogeny of ancestral hydroporines (Coleoptera:Dytiscidae:Hydroporinae)
Authors: Michat Mariano C. , Alarie Yves , Torres Patricia L. M. , Megna Yoandri S.
Published: June 2007

Phylogenetic relationships within diving beetles (Dytiscidae) are imperfectly known. In particular, some authors have considered that the tribe Methlini is included in the subfamily Hydroporinae (a large group including about half of the dytiscid species worldwide), whereas others have argued in favour of excluding Methlini from the Hydroporinae and giving it subfamilial rank. Larval characters have been underutilised in phylogenetic studies, mainly because the larvae of many taxa within the family are still unknown. The larval morphology of the dytiscid tribe Methlini, in particular, remains poorly known. In this study, the phylogenetic relationships among ancestral lineages of the Hydroporinae are investigated based on a cladistic analysis of 34 taxa and 127 morphological larval characters. For this purpose, larvae of the Methlini (Celina parallela (Babington, 1841)) and C. imitatrix Young, 1979) are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy. The results show high support for a monophyletic origin of the Hydroporinae, including Methlini, based on eight unique character states. Giving Methlini subfamily rank would leave Hydroporinae with a single unique larval apomorphy. This supports the inclusion of Methlini as a tribe of Hydroporinae. Other interesting but less well supported results include: 1, the clade Laccornini + Hydrovatini + Canthyporus Zimmermann, 1919 (Hydroporini) resolved as the sister-group to the other Hydroporinae minus Methlini; and 2, Hydrovatini and Canthyporus resolved as sister-groups. The presence of a galea, albeit in a reduced form, in larvae of Methlini, Laccornini and Hydrovatini is of the utmost interest. The putative hypothesis of an ancestral position for these genera within Hydroporinae suggests that hydroporines lost the galea secondarily.
Across Lydekker's Line - first report of mite harvestmen (Opiliones : Cyphophthalmi : Stylocellidae) from New Guinea
Authors: Clouse Ronald M. , Giribet Gonzalo
Published: June 2007

Opiliones (harvestmen) in the suborder Cyphophthalmi are not known to disperse across oceans and each family in the suborder is restricted to a clear biogeographic region. While undertaking a revisionary study of the South-east Asian family Stylocellidae, two collections of stylocellids from New Guinea were noted. This was a surprising find, since the island appears never to have had a land connection with Eurasia, where the rest of the family members are found. Here, 21 New Guinean specimens collected from the westernmost end of the island (Manokwari Province, Indonesia) are described and their relationships to other cyphophthalmids are analysed using molecular sequence data. The specimens represent three species, Stylocellus lydekkeri, sp. nov., S. novaguinea, sp. nov. and undescribed females of a probable third species, which are described and illustrated using scanning electron microscope and stereomicroscope photographs. Stylocellus novaguinea, sp. nov. is described from a single male and it was collected with a juvenile and the three females of the apparent third species. Molecular phylogenetic analyses indicate that the new species are indeed in the family Stylocellidae and they therefore reached western New Guinea by dispersing through Lydekker’s line – the easternmost limit of poor dispersers from Eurasia. The New Guinean species may indicate at least two episodes of oceanic dispersal by Cyphophthalmi, a phenomenon here described for the first time. Alternatively, the presence in New Guinea of poor dispersers from Eurasia may suggest novel hypotheses about the history of the island.
Two distinct but convergent groups of cells trigger Torso receptor tyrosine kinase activation by independently expressing
torso-like
Authors: Furriols Marc , Ventura Gemma , Casanova Jordi
Published: June 2007

Cell fate determination is often the outcome of specific interactions between adjacent cells. However, cells frequently change positions during development, and thus signaling molecules might be synthesized far from their final site of action. Here, we analyze the regulation of the
torso-like
gene, which is required to trigger Torso receptor tyrosine kinase activation in the
Drosophila
embryo. Whereas
torso
is present in the oocyte,
torso-like
is expressed in the egg chamber, at the posterior follicle cells and in two separated groups of anterior cells, the border cells and the centripetal cells. We find that JAK/STAT signaling regulates
torso-like
expression in the posterior follicle cells and border cells but not in the centripetal cells, where
torso-like
is regulated by a different enhancer. The border and centripetal cells, which are originally apart, converge at the anterior end of the oocyte, and we find that both groups contribute to trigger Torso activation. Our results illustrate how independently acquired expression of a signaling molecule can constitute a mechanism by which distinct groups of cells act together in the activation of a signaling pathway.
Exhaust properties of centre-column-limited plasmas on MAST
Authors: Maddison G.P. , Akers R.J. , Brickley C. , Gryaznevich M.P. , Lott F.C. , Patel A. , Sykes A. , Turner A. , Valovič M.
Published: June 2007

The lowest aspect ratio possible in a spherical tokamak is defined by limiting the plasma on its centre column, which might therefore maximize many physics benefits of this fusion approach. A key issue for such discharges is whether loads exhausted onto the small surface area of the column remain acceptable. A first series of centre-column-limited pulses has been examined on MAST using fast infra-red thermography to infer incident power densities as neutral-beam heating was scanned from 0 to 2.5 MW. Simple mapping shows that efflux distributions on the column armour are governed mostly by magnetic geometry, which moreover spreads them advantageously over almost the whole vertical length. Hence steady peak power densities between sawteeth remained low, <1 MW m−2, comparable with the target strike-point value in a reference diverted plasma at lower power. Plasma purity and normalized thermal energy confinement through the centre-column-limited (CCL) series were also similar to properties of MAST diverted cases. A major bonus of CCL geometry is a propensity for exhaust to penetrate through its inner scrape-off layer connecting to the column into an expanding outer plume, which forms a ‘natural divertor’. Effectiveness of this process may even increase with plasma heating, owing to rising Shafranov shift and/or toroidal rotation. A larger CCL device could potentially offer a simpler, more economic next-step design.
Adaptive modulation of sperm production rate in
Drosophila bifurca
, a species with giant sperm
Authors: Bjork Adam , Dallai Romano , Pitnick Scott
Published: June 2007

Sperm have traditionally been regarded as energetically cheap and effectively limitless in supply, although evidence conflicting with this view has become increasingly abundant. For instance, males from a variety of taxa have been shown to strategically partition sperm across ejaculates in response to perceived sperm competition risk. It follows that males might also be predicted to adaptively modulate the rate at which sperm are produced. Here we show that, in the giant sperm producing fruitfly
Drosophila bifurca
, solitary males with infrequent access to females produce sperm at a much lower rate than males raised in association with females and other males. Our results support the prediction that males with little risk of sperm competition risk or few mating opportunities should divert resources away from gamete production.
The three-dimensional locomotor dynamics of African (Loxodonta africana) and Asian (Elephas maximus) elephants reveal a smooth gait transition at moderate speed
Authors: Ren Lei , Hutchinson John R
Published: June 2007

We examined whether elephants shift to using bouncing (i.e. running) mechanics at any speed. To do this, we measured the three-dimensional centre of mass (CM) motions and torso rotations of African and Asian elephants using a novel multisensor method. Hundreds of continuous stride cycles were recorded in the field. African and Asian elephants moved very similarly. Near the mechanically and metabolically optimal speed (a Froude number (Fr) of 0.09), an inverted pendulum mechanism predominated. With increasing speed, the locomotor dynamics quickly but continuously became less like vaulting and more like bouncing. Our mechanical energy analysis of the CM suggests that at a surprisingly slow speed (approx. 2.2 m s−1, Fr 0.25), the hindlimbs exhibited bouncing, not vaulting, mechanics during weight support. We infer that a gait transition happens at this relatively slow speed: elephants begin using their compliant hindlimbs like pogo sticks to some extent to drive the body, bouncing over their relatively stiff, vaulting forelimbs. Hence, they are not as rigid limbed as typically characterized for graviportal animals, and use regular walking as well as at least one form of running gait.
On the dragging of light by a rotating medium
Authors: Götte Jörg B , Barnett Stephen M , Padgett Miles
Published: June 2007

When light is passing through a rotating medium the optical polarization is rotated. Recently, it has been reasoned that this rotation applies also to the transmitted image. We examine these two phenomena by extending an analysis of Player (Player 1976
Proc. R. Soc. A
349
, 441–445) to general electromagnetic fields. We find that in this more general case, the wave equation inside the rotating medium has to be amended by a term which is connected to the orbital angular momentum (OAM) of the light. We show that optical spin and OAM account for the rotation of the polarization and the rotation of the transmitted image, respectively.
Individuation and holistic processing of faces in rhesus monkeys
Authors: Dahl Christoph D , Logothetis Nikos K , Hoffman Kari L
Published: June 2007

Despite considerable evidence that neural activity in monkeys reflects various aspects of face perception, relatively little is known about monkeys' face processing abilities. Two characteristics of face processing observed in humans are a
subordinate-level entry point
, here, the default recognition of faces at the subordinate, rather than basic, level of categorization, and
holistic effects
, i.e. perception of facial displays as an integrated whole. The present study used an adaptation paradigm to test whether untrained rhesus macaques (
Macaca mulatta
) display these hallmarks of face processing. In experiments 1 and 2, macaques showed greater rebound from adaptation to conspecific faces than to other animals at the individual or subordinate level. In experiment 3, exchanging only the bottom half of a monkey face produced greater rebound in aligned than in misaligned composites, indicating that for normal, aligned faces, the new bottom half may have influenced the perception of the whole face. Scan path analysis supported this assertion: during rebound, fixation to the
unchanged
eye region was renewed, but only for aligned stimuli. These experiments show that macaques naturally display the distinguishing characteristics of face processing seen in humans and provide the first clear demonstration that holistic information guides scan paths for conspecific faces.
Fuelling decisions in migratory birds: geomagnetic cues override the seasonal effect
Authors: Kullberg Cecilia , Henshaw Ian , Jakobsson Sven , Johansson Patrik , Fransson Thord
Published: June 2007

Recent evaluations of both temporal and spatial precision in bird migration have called for external cues in addition to the inherited programme defining the migratory journey in terms of direction, distance and fuelling behaviour along the route. We used juvenile European robins (Erithacus rubecula) to study whether geomagnetic cues affect fuel deposition in a medium-distance migrant by simulating a migratory journey from southeast Sweden to the wintering area in southern Spain. In the late phase of the onset of autumn migration, robins exposed to the magnetic treatment attained a lower fuel load than control birds exposed to the ambient magnetic field of southeast Sweden. In contrast, robins captured in the early phase of the onset of autumn migration all showed low fuel deposition irrespective of experimental treatment. These results are, as expected, the inverse of what we have found in similar studies in a long-distance migrant, the thrush nightingale (Luscinia luscinia), indicating that the reaction in terms of fuelling behaviour to a simulated southward migration varies depending on the relevance for the species. Furthermore, we suggest that information from the geomagnetic field act as an important external cue overriding the seasonal effect on fuelling behaviour in migratory birds.
Biomimetic approach to cardiac tissue engineering
Authors: Radisic M , Park H , Gerecht S , Cannizzaro C , Langer R , Vunjak-Novakovic G
Published: June 2007

Here, we review an approach to tissue engineering of functional myocardium that is biomimetic in nature, as it involves the use of culture systems designed to recapitulate some aspects of the actualin vivoenvironment. To mimic the capillary network, subpopulations of neonatal rat heart cells were cultured on a highly porous elastomer scaffold with a parallel array of channels perfused with culture medium. To mimic oxygen supply by haemoglobin, the culture medium was supplemented with a perfluorocarbon (PFC) emulsion. Constructs cultivated in the presence of PFC contained higher amounts of DNA and cardiac markers and had significantly better contractile properties than control constructs cultured without PFC. To induce synchronous contractions of cultured constructs, electrical signals mimicking those in native heart were applied. Over only 8 days of cultivation, electrical stimulation induced cell alignment and coupling, markedly increased the amplitude of synchronous construct contractions and resulted in a remarkable level of ultrastructural organization. The biomimetic approach is discussed in the overall context of cardiac tissue engineering, and the possibility to engineer functional human cardiac grafts based on human stem cells.
Aortic root dynamics and surgery: from craft to science
Authors: Cheng Allen , Dagum Paul , Miller D. Craig
Published: June 2007

Since the fifteenth century beginning with Leonardo da Vinci's studies, the precise structure and functional dynamics of the aortic root throughout the cardiac cycle continues to elude investigators. The last five decades of experimental work have contributed substantially to our current understanding of aortic root dynamics. In this article, we review and summarize the relevant structural analyses, using radiopaque markers and sonomicrometric crystals, concerning aortic root three-dimensional deformations and describe aortic root dynamics in detail throughout the cardiac cycle. We then compare data between different studies and discuss the mechanisms responsible for the modes of aortic root deformation, including the haemodynamics, anatomical and temporal determinants of those deformations. These modes of aortic root deformation are closely coupled to maximize ejection, optimize transvalvular ejection haemodynamics and—perhaps most importantly—reduce stress on the aortic valve cusps by optimal diastolic load sharing and minimizing transvalvular turbulence throughout the cardiac cycle. This more comprehensive understanding of aortic root mechanics and physiology will contribute to improved medical and surgical treatment methods, enhanced therapeutic decision making and better post-intervention care of patients. With a better understanding of aortic root physiology, future research on aortic valve repair and replacement should take into account the integrated structural and functional asymmetry of aortic root dynamics to minimize stress on the aortic cusps in order to prevent premature structural valve deterioration.
The use of taxonomic distinctness to assess environmental disturbance of insect communities from running water
Authors: MARCHANT RICHARD
Published: June 2007

1. Taxonomic distinctness (or average taxonomic breadth) of a sample is a measure of diversity that has the great advantage of not being sensitive to variations in sampling effort, unlike measures of species richness. It can also be tested for departures from expectation and can thus be used to determine whether a site has suffered from a genuine loss of diversity.

2. Taxonomic distinctness or delta+ was measured using all insect species from three datasets obtained from running water habitats: reference or least disturbed sites from channel and bank habitats on rivers from the Australian state of Victoria; test sites distributed along a water quality gradient in Victoria and sites immediately below a series of dams in Victoria and New South Wales. The last two datasets comprised sites subject to a range of obvious disturbances.

3. At reference sites delta+ was generally within the range of expected values (95% confidence limits) for both habitats as would be anticipated for these essentially undisturbed sites. However, 13–14% of sites fell below the lower confidence limits. Sites in river basins with less cover of natural habitat had slightly but significantly lower delta+ values than those with more cover and these sites contributed to this anomaly.

4. Delta+ was inversely correlated with water quality (r = −0.54, P = 0.002) as measured by the first axis of a PCA of water quality variables. It was also inversely correlated with individual variables, such as turbidity and total phosphorous.

5. Delta+ was below expectation for 18 of the 19 dam sites and at 13 of these sites delta+ values were below the lower confidence limit.

6. Delta+ was a sensitive index of diversity that generally distinguished sites suffering from environmental disturbance. Only a few previous studies of river ecosystems have used delta+, which did not respond consistently to disturbance because either too few taxa at species or higher taxonomic levels were available or because longitudinal changes in species composition swamped the signal from delta+. Neither of these problems occurred with the current datasets.

7. Delta+ responded more readily to disturbance than number of species, perhaps because taxonomic distinctness reflects some of the multivariate nature of community samples, whereas number of species is blind to this aspect.
Species‐specific responses of planktivorous fish to the introduction of a new piscivore: implications for prey fitness
Authors: HÖLKER FRANZ , DÖRNER HENDRIK , SCHULZE TORSTEN , HAERTEL‐BORER SUSANNE S. , PEACOR SCOTT D. , MEHNER THOMAS
Published: June 2007

1. Antipredator behaviour by the facultative planktivorous fish species roach (Rutilus rutilus), perch (Perca fluviatilis) and rudd (Scardinius erythrophthalmus) was studied in a multi‐year whole‐lake experiment to evaluate species‐specific behavioural and numerical responses to the stocking of pikeperch (Sander lucioperca), a predator with different foraging behaviour than the resident predators large perch (P. fluviatilis) and pike (Esox lucius).

2. Behavioural responses to pikeperch varied greatly during the night, ranging from reduced activity (roach and small perch) and a shift in habitat (roach), to no change in the habitat use and activity of rudd. The differing responses of the different planktivorous prey species highlight the potential variation in behavioural response to predation risk from species of similar vulnerability.

3. These differences had profound effects on fitness; the density of species that exhibited an antipredator response declined only slightly (roach) or even increased (small perch), whereas the density of the species that did not exhibit an antipredator response (rudd) decreased dramatically (by more than 80%).

4. The maladaptive behaviour of rudd can be explained by a ‘behavioural syndrome’, i.e. the interdependence of behaviours expressed in different contexts (feeding activity, antipredator) across different situations (different densities of predators).

5. Our study extends previous studies, that have typically been limited to more controlled situations, by illustrating the variability in intensity of phenotypic responses to predators, and the consequences for population density, in a large whole‐lake setting.
Population genetic structure reveals terrestrial affinities for a headwater stream insect
Authors: FINN DEBRA S. , BLOUIN MICHAEL S. , LYTLE DAVID A.
Published: June 2007

1. The spatial distribution of stream‐dwelling organisms is often considered to be limited primarily according to the hierarchical structure of the hydrologic network, and previous conceptual models of population genetic structure have reflected this generality. Headwater specialists, however, are confined to short upstream sections of the network, and therefore are unlikely to respond in the same way as species with a broader range of habitat tolerance.

2. Here, we propose a model to describe spatial patterns of genetic diversity in headwater specialists with a limited ability for among‐stream dispersal. The headwater model predicts a partitioning of genetic variance according to higher‐elevation ‘islands’ of terrestrial habitat that provide required headwater stream conditions. The model therefore expects a geographic pattern of genetic variance similar to that expected for low‐dispersal terrestrial species occupying the adjacent habitat.

3. Using a 1032‐bp mitochondrial DNA fragment encompassing parts of the COI and COII genes, we demonstrate that Madrean Sky Islands populations of the giant water bug Abedus herberti conform to the proposed headwater model. Furthermore, they exhibit phylogeographic patterns broadly concordant with those shown for several terrestrial species in the region, including a major zone of discontinuity in the Chiricahua mountain range.

4. Overall, populations are highly isolated from one another, and a nested clade analysis suggested that A. herberti population structure, similarly to terrestrial Sky Islands species studied previously, has been influenced by Pleistocene climatic cycles causing expansion and contraction of temperate woodland habitat.

5. Because they have no ability to disperse among present‐day mountaintop habitat islands, A. herberti and other headwater species with limited dispersal ability are vulnerable to the projected increasing rate of climatic warming in this region.
Seasonal changes in morphometric and biochemical endpoints in northern pike (Esox lucius), burbot (Lota lota) and slimy sculpin (Cottus cognatus)
Authors: BENNETT PAMELA M. , JANZ DAVID M.
Published: June 2007

1. Morphometric and biochemical endpoints were used to assess growth and energetics in young‐of‐the‐year (YOY) northern pike (Esox lucius), YOY burbot (Lota lota) and slimy sculpin (Cottus cognatus) collected upstream and downstream of a uranium mining operation in northern Saskatchewan, Canada.

2. Water sampled at sites downstream of uranium mining and milling effluent discharge was higher in certain trace metals (arsenic, molybdenum), ions (conductivity, hardness, ammonia and sulphate) and total dissolved solids compared with ecologically similar reference sites.

3. Overwinter survival potential was estimated by determining total body lipids and total body triglycerides in fishes collected in late autumn and early spring. Two‐factor anova indicated no site or season differences in total body lipids or triglycerides in YOY northern pike. In spring, burbot collected from the exposure site were higher in total body lipids and triglycerides compared with the previous autumn and compared with fish collected from the reference site. Slimy sculpin from both exposure and reference sites had lower total body lipid and triglyceride content in spring compared with the previous autumn. In addition, sculpin from the exposure site had lower total body lipids and triglycerides in spring compared with fish collected from the reference site.

4. Biochemical estimates of fish growth (muscle RNA/DNA ratio and muscle protein concentration) exhibited clear seasonal differences, with consistent decreases in this endpoint for all fish species in spring relative to the previous autumn at both exposure and reference sites.

5. Results for total body lipids and triglycerides were inconclusive and inconsistent between species and exposure scenarios. However, all species exhibited a similar seasonal decrease in muscle protein and to a lesser extent, muscle RNA/DNA ratio.
Pleuston communities are buffered from regional flood pulses: the example of ostracods in the Paraná River floodplain, Brazil
Authors: HIGUTI JANET , VELHO LUIZ FELIPE MACHADO , LANSAC‐TÔHA FÁBIO AMODÊO , MARTENS KOEN
Published: June 2007

1. It is widely acknowledged that sudden, large‐scale flood pulses are drivers of benthic and planktonic biodiversity change in floodplains. The impact of such pulses on pleuston (biotic communities associated with root systems of floating plants) remains to be demonstrated. Here, we investigate the effects of local and regional drivers on seasonal changes in abundance and diversity of ostracod communities in pleuston.

2. Temporal and spatial distribution patterns of species richness, abundance, diversity and evenness of ostracods associated with the floating water hyacinth, Eichhornia crassipes, in a lentic environment from the upper Paraná River floodplain, were investigated in relation to local, as well as regional, environmental factors. Ostracods were sampled monthly over an annual cycle (March 2004–February 2005). Twenty‐seven species were found, representing the families Cyprididae, Candonidae, Limnocytheridae and Darwinulidae. Both diversity and abundance of ostracod communities showed seasonal changes, although species turn‐over during the year was limited.

3. We tested two hypotheses concerning the causality of these fluctuations: seasonal recruitment and influx of allochthonous ostracods during the flood pulse. Our results indicate that seasonal recruitment is more likely to be the driver of fluctuations in relation to the flood pulse. We postulate that pleuston communities are buffered against possible detrimental effects of flood pulses.
Implementation of a proficiency testing programme for bacterial screening in platelet preparations in Canada
Authors: Mastronardi C. , Martincic I. , Ramírez‐Arcos S.
Published: June 2007

Background and Objectives  Bacterial screening in apheresis platelet preparations was implemented in March of 2004 by Canadian Blood Services (CBS) using the BacT/ALERT® system. The aim of this study was to develop, validate and implement an in‐house proficiency testing programme to evaluate CBS performance of bacterial screening in platelet preparations.

Study Design and Methods  During development of the proficiency testing programme, apheresis platelet preparations were spiked with 101 and 102 colony forming units per ml of Staphylococcus epidermidis, Pseudomonas aeruginosa and Streptococcus pneumoniae. The preparations were stored at 2–8 °C prior to culture bottle inoculation with 4 or 6 ml on Days 7–10 (estimated time from panel preparation to testing at CBS centres). Upon implementation, a combination of four proficiency panel members, including positives and negatives, were distributed to each of the centres that participated in the programme. A survey was conducted with 43 America's Blood Centers to assess whether they screen for bacterial testing in platelet preparations and whether they have implemented a proficiency testing programme.

Results  The development of the proficiency testing programme showed that S. epidermidis and P. aeruginosa produced positive results at both concentrations and volumes on Days 7–10 poststorage. Streptococcus pneumoniae did not grow consistently and therefore was not selected for implementation of the programme. Two proficiency testing panel sets have been issued (July 2006 and February 2007) with 14 out of 15 (93%) and 14 out of 14 (100%) of the participant centres meeting the expected results for bacterial screening, respectively. The majority (72%) of the America's Blood Centers that screen for bacterial contamination have not implemented a proficiency testing programme and 94.4% of these centres are interested in developing such a programme.

Conclusion  Canadian Blood Services has successfully implemented a proficiency testing programme for bacterial screening in platelet preparations, which will contribute to improving the safety of the platelet supply in Canada.
ROLE OF OESTROGEN IN THE CENTRAL REGULATION OF AUTONOMIC FUNCTION
Authors: Saleh TM , Connell BJ
Published: June 2007

In recent years, the role of oestrogen in women's health has been a subject of considerable scientific and popular debate. There is unquestionable evidence that oestrogen has both potent and long‐lasting effects on several vital organ systems, including the cardiovascular system, the autonomic nervous system and, most recently, within the central nervous system itself.

The research and medical community continues to debate whether the benefits of oestrogen therapy outweigh the risks in the treatment of the symptoms of menopause, the attenuation of the risk for cardiovascular insults, such as stroke and heart disease, and even the retardation of the progression of Alzheimer's disease.

The recent evidence provided by the Heart and Estrogen/Progestin Replacement Study (HERS) II clinical trial suggesting that long‐term exposure to combined oestrogen and progestin in post‐menopausal women who have previously had a heart attack or stroke (for secondary prevention) may actually increase their risk of a subsequent cardiovascular insult has further fuelled the debate. However, there remain considerable gaps in our knowledge with respect to the actual mechanisms by which oestrogen exerts its various beneficial effects at the cellular level for the primary prevention of cardiovascular disease. This information is essential if we are to harness the positive aspects of oestrogen therapy in such a manner as to avoid or minimize the associated risks of increased oestrogen exposure in women who we know, with some certainty, to be at an increased risk of cancers of the uterus, cervix and breast tissue.
EFFECTS OF APOCYNIN AND ETHANOL ON INTRACEREBRAL HAEMORRHAGE‐INDUCED BRAIN INJURY IN RATS
Authors: Titova Elena , Ostrowski Robert P , Sowers Lawrence C , Zhang John H , Tang Jiping
Published: June 2007

In the present study, we investigated whether the administration of apocynin, an NADPH oxidase inhibitor, provided brain protection in a rat model of intracerebral haemorrhage (ICH).

Rats were divided into sham, ICH untreated, ICH treated with vehicle (ethanol) and ICH treated with apocynin groups. Intracerebral haemorrhage was induced by collagenase injection. Neurological function, haemorrhage volume and brain oedema were measured 24 h after ICH.

Intracerebral haemorrhage caused significant neurological deficit associated with brain oedema. Apocynin (3, 10 and 30 mg/kg) failed to reduce brain injury after ICH. Low dose ethanol (0.2 g/kg) improved neurological function and reduced brain oedema (ICH‐vehicle vs ICH‐untreated, P < 0.05).

In conclusion, apocynin has no neuroprotective effect when administered intraperitoneally after ICH.
VASODILATATION INDUCED BY SINOMENINE LOWERS BLOOD PRESSURE IN SPONTANEOUSLY HYPERTENSIVE RATS
Authors: Lee Ping‐Ying , Chen Wency , Liu I‐Min , Cheng Juei‐Tang
Published: June 2007

Sinomenine is an alkaloid with a wide range of pharmacological actions. In the present study, we investigated the effect of sinomenine on blood pressure and its possible mechanisms of action.

Spontaneously hypertensive rats (SHR) and normotensive Wistar‐Kyoto (WKY) rats were given intraperitoneal injections of sinomenine. At 30 min, 2.5–10 mg/kg sinomenine decreased systolic blood pressure (SBP) in a dose‐dependent manner in SHR, but had no effect on the SBP in WKY rats.

The vascular effect of sinomenine was then examined in aortic rings isolated from Wistar rats. Sinomenine (0.1–10 mmol/L) produced concentration‐dependent relaxation in aortic rings precontracted with phenylephrine (10 nmol/L) or KCl (40 mmol/L). Glibenclamide (1–100 mmol/L), a specific inhibitor of ATP‐sensitive K+ channels attenuated the sinomenine‐induced relaxation, but this effect was not observed when inhibitors of other types of K+ channels were used.

We further investigated the effects of sinomenine on changes in intracellular Ca2+ concentrations ([Ca2+]i) in cultured aortic smooth muscle (A7r5) cells by using the Ca2+‐sensitive dye fura‐2 as an indicator. Sinomenine, over the concentration range 0.1–10 mmol/L, decreased the increases in [Ca2+]i elicited by phenylephrine (1 mmol/L) or KCl (40 mmol/L) in a concentration‐dependent manner. Glibenclamide (1–100 mmol/L) abolished the effects of sinomenine.

In conclusion, sinomenine causes vascular relaxation by opening ATP‐sensitive K+ channels, thus decreasing [Ca2+]i.
NEGATIVE INOTROPIC AND LUSITROPIC EFFECTS OF INTRAVENOUS AMIODARONE IN CONSCIOUS RATS
Authors: Salgado Helio C , Simões Géssica M , Santana Filho Valter J , Dias da Silva Valdo J , Salgado Maria Cristina O , Fazan Rubens
Published: June 2007

The acute effect of amiodarone on haemodynamics (mean arterial pressure and heart rate) and ventricular function (+dP/dtmax and –dP/dtmax) was investigated in conscious rats. In addition, the effects of amiodarone on dobutamine stress were determined.

Catheters were inserted in rats into the left ventricle and femoral artery and vein. Three groups of rats received 25 or 50 mg/kg, i.v., amiodarone or vehicle (a 1 : 1 : 8 mixture of Tween 80 : 99.5% ethanol : distilled water), followed by dobutamine (10 µg/kg).

The hypotensive effect of 50 mg/kg amiodarone was combined with marked bradycardia and attenuation of +dP/dtmax and –dP/dtmax. A slight, but significant, hypotension was caused by 25 mg/kg amiodarone, without affecting heart rate, +dP/dtmax and –dP/dtmax. However, although both doses of amiodarone attenuated the tachycardia caused by dobutamine, neither 25 nor 50 mg/kg amiodarone affected the increase in mean arterial pressure or the enhanced response of +dP/dtmax and –dP/dtmax.

In conclusion, amiodarone caused hypotension, bradycardia, negative inotropic (+dP/dtmax) and lusitropic (–dP/dtmax) effects in conscious rats. In addition, amiodarone attenuated the tachycardia without affecting the hypertensive, contractile (+dP/dtmax) and lusitropic (–dP/dtmax) responses to dobutamine stress.
Effects of phenylacetaldehyde and (Z)‐3‐hexenyl acetate on male response to synthetic sex pheromone in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)
Authors: Kvedaras Olivia L , Del Socorro Alice P , Gregg Peter C
Published: June 2007

Abstract  The influence of two synthetic plant volatiles on the number of male Helicoverpa armigera (Hübner 1808) (Lepidoptera: Noctuidae) caught in sex pheromone‐baited traps was studied in field plots in Australia. Phenylacetaldehyde and (Z)‐3‐hexenyl acetate were combined with synthetic sex pheromone in traps. Generally, most males were captured in traps baited with pheromone alone and more males were captured by the mixture containing (Z)‐3 hexenyl acetate than that containing phenylacetaldehyde. At the three concentrations studied, neither volatile synergised the activity of the pheromone. Traps baited with the plant volatiles alone caught very few moths of either sex.
Pheromone trapping of the sugarcane weevil borer, Rhabdoscelus obscurus (Boisduval) (Coleoptera: Curculionidae): an evaluation of trap design and placement in the field
Authors: Sallam Mohamed N , Peck Darren R , McAvoy Catherine A , Donald David A
Published: June 2007

Abstract  The sugarcane weevil borer (Rhabdoscelus obscurus) is a pest of sugarcane and palm plantations in high rainfall areas of far north Queensland. Pheromone mass trapping of adult borers is an effective method of monitoring and may also impact on their population densities. Trials to evaluate different designs of pheromone trap showed the ‘water trap’ to be the most effective in capturing the highest number of adult borers. The water trap is a 20 cm‐diameter pot with a plastic bag inserted to hold water with pheromone lures and cane pieces held together in a plastic container suspended over the water from a square of wire mesh. Results also showed that adult borers in adjacent fields are able to sense the lures and migrate into treated fields. The sex ratio of captured borers in split‐cane traps (which is a standard population monitoring tool) was male biased from February to April but was more balanced later in the year. However, the pheromone traps mainly attracted female borers all year round, except during May. Thus, we recommend pheromone traps to be deployed early in the season (November to early December) to attract the maximum number of adult females at a critical time for the population as it starts to build up. In addition, placing pheromone traps inside cane paddocks did not improve the total catch in most cases. Therefore, placing pheromone traps under the shade of trees outside the paddock or at the edge of the paddock under sugarcane can be a feasible mass trapping method that can easily be implemented by cane growers.
In situ lateral transfer of symbiosis islands results in rapid evolution of diverse competitive strains of mesorhizobia suboptimal in symbiotic nitrogen fixation on the pasture legume Biserrula pelecinus L.
Authors: Nandasena Kemanthi G. , O'Hara Graham W. , Tiwari Ravi P. , Sezmiş Ertuğ , Howieson John G.
Published: June 2007

The multi‐billion dollar asset attributed to symbiotic nitrogen fixation is often threatened by the nodulation of legumes by rhizobia that are ineffective or poorly effective in N2 fixation. This study investigated the development of rhizobial diversity for the pasture legume Biserrula pelecinus L., 6 years after its introduction, and inoculation with Mesorhizobium ciceri bv. biserrulae strain WSM1271, to Western Australia. Molecular fingerprinting of 88 nodule isolates indicated seven were distinctive. Two of these were ineffective while five were poorly effective in N2 fixation on B. pelecinus. Three novel isolates had wider host ranges for nodulation than WSM1271, and four had distinct carbon utilization patterns. Novel isolates were identified as Mesorhizobium sp. using 16S rRNA, dnaK and GSII phylogenies. In a second study, a large number of nodules were collected from commercially grown B. pelecinus from a broader geographical area. These plants were originally inoculated with M. c bv. biserrulae WSM1497 5–6 years prior to isolation of strains for this study. Nearly 50% of isolates from these nodules had distinct molecular fingerprints. At two sites diverse strains dominated nodule occupancy indicating recently evolved strains are highly competitive. All isolates tested were less effective and six were ineffective in N2 fixation. Twelve randomly selected diverse isolates clustered together, based on dnaK sequences, within Mesorhizobium and distantly to M. c bv. biserrulae. All 12 had identical sequences for the symbiosis island insertion region with WSM1497. This study shows the rapid evolution of competitive, yet suboptimal strains for N2 fixation on B. pelecinus following the lateral transfer of a symbiosis island from inoculants to other soil bacteria.
The attribution of attention: 9‐month‐olds’ interpretation of gaze as goal‐directed action
Authors: Johnson Susan C. , Ok Su‐Jeong , Luo Yuyan
Published: June 2007

The current study distinguishes between attributions of goal‐directed perception (i.e. attention) and non‐goal‐directed perception to examine 9‐month‐olds’ interpretation of others’ head and eye turns. In a looking time task, 9‐month‐olds encoded the relationship between an actor's head and eye turns and a target object if the head and eye turns were embedded in a sequence of multiple, variable actions with equifinal outcomes, but not otherwise. This evidence supports the claim that infants of this age may attribute perception, at least goal‐directed perception, to others and undermines arguments that gaze‐following at this age consists only of uninterpreted reflexes. The evidence also suggests alternative interpretations of the typical errors infants make in standard gaze‐following procedures. Implications for infants’ understanding of perception and attention in both human and non‐human agents are discussed.