bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sonographic measurement of cervical length in preterm prelabor amniorrhexis
Authors: Tsoi E. , Fuchs I. , Henrich W. , Dudenhausen J. W. , Nicolaides K. H. 
Published: September 2004

AbstractObjectiveTo determine whether sonographic measurement of cervical length in pregnancies complicated by preterm prelabor amniorrhexis helps distinguish between those women who deliver within 7 days and those who do not.MethodsIn 101 women with singleton pregnancies presenting with preterm prelabor amniorrhexis at 24–36 (median, 32) weeks of gestation cervical length was measured by transvaginal ultrasound. Exclusion criteria were active labor defined by the presence of cervical dilatation of ≥ 3 cm and iatrogenic delivery for fetal or maternal indication when not in active labor. The clinical management was determined by the attending obstetrician. The primary outcome of the study was delivery within 7 days of presentation.ResultsDelivery within 7 days of presentation occurred in 58/101 (57%) pregnancies. Logistic regression analysis demonstrated that significant independent contribution in the prediction of delivery within 7 days was provided by cervical length (odds ratio (OR) = 0.91, 95% CI 0.86–0.96, P = 0.001), gestation at presentation (OR = 1.35, 95% CI 1.14–1.59, P = 0.001) and presence of contractions at presentation (OR = 3.07, 95% CI 1.05–8.92, P = 0.039) with no significant independent contribution from ethnic origin, maternal age, body mass index, parity, previous history of preterm delivery, cigarette smoking, vaginal bleeding or the administration of tocolytics, antibiotics or steroids.ConclusionIn women with preterm prelabor amniorrhexis prediction of delivery within 7 days is provided by cervical length, gestation and presence of contractions at presentation. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Low power microwave interaction with phospholipase C and D signal transduction pathways in myogenic cells
Authors: Donato Andrea , Ceci Paola , Cannavò Andrea , Tomei Francesco , Naro Fabio 
Published: September 2004

AbstractIonic channel proteins are possible sites of microwave interaction at the cell membrane level. Patch‐clamp data, using single channel and total current recording, indicated that low level microwave fields may modify some functional parameters of the nicotinic acetylcholine receptor in primary chick myotubes, suggesting a possible effect of microwaves on myogenic cells. Here, we investigated the biological relevance of such results, in relation to the possible involvement of intracellular signaling processes. We exposed L6–C5 myogenic cells to low power electromagnetic fields and observed the consequences on hormonal activation of phospholipases C and D. We found that increased inositol phospholipid turnover, induced by acetylcholine and arginine vasopressin activation of phospholipase C, was not modified in microwave irradiated myoblasts or myotubes. Moreover, vasopressin‐dependent phospholipase D activation, assessed by measuring the [3H]‐free choline release, was not modified by microwave irradiation. Our conclusions suggest that low level microwave fields do not modify signal transduction pathways activated by acetylcholine and vasopressin in L6–C5 myogenic cells.
Response of clupeid fish to ultrasound: a review
Authors: Popper Arthur N. , Plachta Dennis T.T. , Mann David A. , Higgs Dennis 
Published: September 2004

AbstractA number of species of clupeid fish, including blueback herring, American shad, and gulf menhaden, can detect and respond to ultrasonic sounds up to at least 180 kHz, whereas other clupeids, including bay anchovies and Spanish sardines, do not appear to detect sounds above about 4 kHz. Although the location for ultrasound detection has not been proven conclusively, there is a growing body of physiological, developmental, and anatomical evidence suggesting that one end organ of the inner ear, the utricle, is likely to be the detector. The utricle is a region of the inner ear that is very similar in all vertebrates studied to date, except for clupeid fish, where it is highly specialized. Behavioural studies of the responses of American shad to ultrasound demonstrate that they show a graded series of responses depending on the sound level and, to a lesser degree, on the frequency of the stimulus. Low-intensity stimuli elicit a non-directional movement of the fish, whereas somewhat higher sound levels elicit a directional movement away from the sound source. Still higher level sounds produce a “wild” chaotic movement of the fish. These responses do not occur until shad have developed the adult utricle that has a three-part sensory epithelium. We speculate that the response of the American shad (and, presumably, other clupeids that can detect ultrasound) to ultrasound evolved to help these species detect and avoid a major predator – echolocating cetaceans. As dolphins echolocate, the fish are able to hear the sound at over 100 m. If the dolphins detect the fish and come closer, the nature of the behavioural response of the fish changes in order to exploit different avoidance strategies and lower the chance of being eaten by the predators.
Diel vertical behaviour, predator–prey relationships, and occupation of space by jack mackerel (Trachurus murphyi) off Chile
Authors: Bertrand Arnaud , Barbieri Maria Angela , Córdova Jose , Hernández Carola , Gómez Fabián , Leiva Francisco 
Published: September 2004

Abstract
In the southeastern Pacific, jack mackerel (Trachurus murphyi, Carangidae) is a heavily exploited pelagic species, and its presence in Chilean waters in autumn and winter is assumed to be mainly due to an inshore feeding migration. Predator–prey relationships are known to depend on the spatial and temporal scale of observation, but they can also be strongly affected by factors such as diel vertical migration. In studying the case of jack mackerel in detail, we used data from three acoustic surveys carried out in central Chile in 1997, 1998, and 1999. In terms of spatial occupation, jack mackerel behaviour is “atypical” behaviour, i.e. more aggregated during the night than during the day. The patterns we observed can be related to their nocturnal active foraging behaviour. Diel feeding behaviour is therefore a key factor in the aggregating behaviour of jack mackerel and its vulnerability to the purse-seine fishery that targets these nocturnal aggregations. This particular fish diel feeding behaviour also affected predator–prey relationships in relation to the spatial scale. Positive correlations at a “small” spatial scale (<7–25 km) were observed during the night when jack mackerel foraged, but not during the day. Finally, we show that prey biomass was lower where jack mackerel were abundant, which could indicate a jack mackerel top–down control on prey communities.
Influence of seismic shooting on the lesser sandeel (Ammodytes marinus)
Authors: Hassel Arne , Knutsen Tor , Dalen John , Skaar Kristian , Løkkeborg Svein , Misund Ole Arve , Østensen Øivind , Fonn Merete , Haugland Eli Kyrkjebø 
Published: September 2004

Abstract
A field experiment on the effect of seismic shooting on the lesser sandeel (Ammodytes marinus) was conducted on the fishing grounds in the southeastern part of the North Sea in May 2002. Sandeel buried in the sand at night were trapped in steel frame cages (2.0 × 1.8 × 2.0 m) deployed in positions with high abundance of fish located by a van Veen grab. In an experimental area, three sandeel cages were exposed to full-scale seismic shooting for about 2.5 d. Cameras in the cage and on a remotely operated vehicle (ROV) were used to monitor the activity of the enclosed fish. A control area about 35 km southeast of the seismic shooting area was established with two sandeel cages. The distribution and abundance of the lesser sandeel during daytime in the experimental region were regularly monitored by acoustic surveying, but the present methodology could not demonstrate that seismic shooting caused any change in sandeel abundance. Repeated grab surveys were conducted using a van Veen grab for a predetermined set of localities almost every night during the experimental period, both prior to and after seismic shooting. The results indicate that the seismic shooting had a moderate effect on the behaviour of the lesser sandeel. We did not observe any immediate lethal effect, neither from the cage experiments nor from the grab samples. The total mortality in the cages of about 35% on average, both in the experimental group and the control group, was probably a result of injuries during deployment, due to handling and confinement. Analyses of landing data from the Norwegian sandeel trawlers show a temporary drop in the sandeel landings for a short period after the seismic experiment.
Cutaneous stimulation from patella tape causes a differential increase in vasti muscle activity in people with patellofemoral pain
Authors: MacGregor Kerren , Gerlach Sharon , Mellor Rebecca , Hodges Paul W. 
Published: September 2004

AbstractPatella taping reduces pain in individuals with patellofemoral pain (PFP), although the mechanism remains unclear. One possibility is that patella taping modifies vasti muscle activity via stimulation of cutaneous afferents. The aim of this study was to investigate the effect of stretching the skin over the patella on vasti muscle activity in people with PFP. Electromyographic activity (EMG) of individual motor units in vastus medialis obliquus (VMO) was recorded via a needle electrode and from surface electrodes placed over VMO and vastus lateralis (VL). A tape was applied to the skin directly over the patella and stretch was applied via the tape in three directions, while subjects maintained a gentle isometric knee extension effort at constant force. Recordings were made from five separate motor units in each direction. Stretch applied to the skin over the patella increased VMO surface EMG and was greatest with lateral stretch. There was no change in VL surface EMG activity. While there was no net increase in motor unit firing rate, it was increased in the majority of motor units during lateral stretch. Application of stretch to the skin over VMO via the tape can increase VMO activity, suggesting that cutaneous stimulation may be one mechanism by which patella taping produces a clinical effect. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
The impact of exotic trout on native charr in a Japanese stream
Authors: MORITA KENTARO , TSUBOI JUN‐ICHI , MATSUDA HIROYUKI 
Published: September 2004

Summary

Regression and isodar methods developed by community ecologists provide tools for evaluating the existence and magnitude of interspecific interactions in the field. In this study, we examined the usefulness of both methods to assess the impact of exotic trout on native charr.
Brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss have been introduced world‐wide. They are invading many streams in Japan that also harbour native salmonids. We studied these species and the endemic Asian white‐spotted charr Salvelinus leucomaenis in the Hekirichi River, south‐western Hokkaido, Japan. We estimated the densities of all three species in pools and riffles from 27 stream reaches over 2 successive years. Data were analysed by regression and isodar methods to infer interspecific interactions.
The regression method identified a negative relationship between brown trout and white‐spotted charr densities, implying that brown trout are replacing white‐spotted charr.
The isodar method identified significant competition for habitat between rainbow trout and white‐spotted charr. This method suggested that white‐spotted charr preferred pools to riffles when rainbow trout were scarce but moved from pools to riffles as trout density in the pools increased.
Synthesis and applications. Although they are based on limited data, regression and isodar methods were able to evaluate the potential impact of exotic trout on native white‐spotted charr. From these results, we were able to hypothesize mechanisms of displacement of native charr by exotic trout. However, according to the two methods the mechanisms underlying the negative impacts on charr differ between brown and rainbow trout; in other words, limitations exist for both methods. From a more practical viewpoint, the analyses conducted in this study may be useful tools for conservation biologists who have limitations on their time and effort but must assess the impacts of exotics on native species.
Effects of habitat cover, landscape structure and spatial variables on the abundance of birds in an agricultural–forest mosaic
Authors: HEIKKINEN RISTO K. , LUOTO MISKA , VIRKKALA RAIMO , RAINIO KALLE 
Published: September 2004

Summary

Numerical studies of the relationship between birds and their habitat are important because they provide understanding of the impacts of natural and human factors on avian diversity. However, collinearity between explanatory variables and spatial autocorrelation can hamper the detection of key environmental factors underlying bird–environment relationships identified by traditional regression approaches. This study utilized two alternative statistical methods to address these difficulties in biodiversity modelling.
We examined bird abundance patterns, spatial structure and relationship to environmental factors in an agricultural–forest mosaic landscape in Finland. We used data from 105 grid squares each 25 ha in size. Using variation partitioning and hierarchical partitioning methods, we determined the independent and joint effects of habitat cover, landscape structure and spatial variables on the total number of bird pairs and that of agricultural bird pairs.
The explanatory variables highlighted as important predictors of bird patterns by the two methods generally coincided well. The total number of bird pairs was negatively related to agricultural land, and positively to cover of forests and landscape heterogeneity. However, a clear majority of the explained variation in bird patterns was related to the joint effect of predictors, and the independent contributions of predictors were small. The univariate importance of landscape heterogeneity decreased greatly if the habitat cover variables were considered simultaneously.
Most of the explained variation in the number of agricultural bird pairs was related to the joint effects of the explanatory variables. In addition, the independent effect of habitat cover variables was considerable and agricultural birds showed a positive relationship with semi‐natural grasslands.
Synthesis and applications. Variation partitioning and hierarchical partitioning approaches provide deeper insights into bird–environment relationships than traditional regression methods. This is particularly so when they are employed in a complementary manner. Our results indicate that a major part of the spatial structure in bird patterns in agricultural–forest mosaics can be caused by the clumping of habitats either preferred or avoided by birds. Moreover, at a scale of 25 ha, the abundance of bird pairs is not necessarily related to landscape heterogeneity as such, but depends more on the distribution of the most important habitats for birds.
Impact of habitat management on grey partridge populations: assessing wildlife cover using a multisite BACI experiment
Authors: BRO ELISABETH , MAYOT PIERRE , CORDA EVE , REITZ FRANÇOIS 
Published: September 2004

Summary

The grey partridge is a species of conservation concern, in common with many farmland birds. Its widespread decline in western Europe has been attributed to agricultural intensification. Attempts to restore populations have concentrated upon habitat management. In France, a mosaic of strips planted with maize‐ or kale‐based mixtures is widely used to benefit the grey partridge on intensively cultivated farmlands. The rationale for planting these summer‐to‐winter cover strips is to increase the overwinter survival rate and hence breeding density. Although this policy is costly to apply, there is little information on its effectiveness.
We tested effectiveness of this management scheme as a practical way of improving or restoring partridge populations. We present data from a 6‐year before–after control–impact (BACI) experiment replicated across four study sites. We monitored partridge populations to estimate breeding density, reproductive success and overwinter mortality.
During the course of the study, no partridge population increase occurred on managed areas compared with control areas. Wildlife cover strips did not improve reproductive success but were associated with higher overwinter ‘apparent mortality’ rates.
Some field data suggested that there was a predation risk at cover strip–field edges. Cover strips may concentrate a number of species within small isolated areas and may act, under some circumstances, as an ecological trap for prey species such as the grey partridge. Due to these complex and unforeseen interactions, this habitat management measure proved unsuitable for partridge restoration.
Synthesis and applications. This study has demonstrated the necessity of field experiments at a farm‐scale to test the effectiveness of habitat management schemes. A priori assumptions based on smaller scale studies, even if they are supported by some field evidence, can be misleading because they fail to capture the emergent properties of larger scale systems. This study is a specific illustration of how the BACI approach is a powerful tool for addressing wildlife management problems at large spatial scales.
Facilitating grassland diversification using the hemiparasitic plant Rhinanthus minor
Authors: PYWELL RICHARD F. , BULLOCK JAMES M. , WALKER KEVIN J. , COULSON SARAH J. , GREGORY STEVE J. , STEVENSON MARK J. 
Published: September 2004

Summary

Species‐rich grasslands are of high conservation value because of the diverse floral and faunal assemblages they support. Intensive agriculture has resulted in the large‐scale loss and fragmentation of this habitat throughout the UK and Europe.
Diversification of species‐poor grasslands has proved to be problematical due to seed limitation, lack of microsites for germination and competition from established species.
Studies of semi‐natural grasslands in Britain and Europe suggest that the presence of hemiparasitic angiosperms of the genus Rhinanthus is correlated with local decreases in productivity and an associated increase in species richness.
In 1998 a randomized block experiment was established to examine: (i) the practicality of introducing Rhinanthus minor into a productive grassland from seed; (ii) the rate of establishment and colonization of the introduced populations; and (iii) the relationship between the frequency of the parasite and the establishment and persistence of introduced forb species.
Establishment of Rhinanthus was less likely at the lowest sowing rate (0·1 kg ha−1) and population growth was initially slow compared with the higher seed rates (0·5 and 2·5 kg ha−1). After the first year, populations grew rapidly and colonized the unsown plots, so that after 4 years there was little difference in Rhinanthus frequency between treatments.
In October 2000, 2 years after sowing Rhinanthus, a native wildflower seed mixture was oversown into a number of the treatments at 5 kg ha−1. The mixture comprised 10 forbs of which nine species were previously not present in the grassland. All forbs established with up to seven species m−2. This resulted in an increase in mean richness of sown species of 0·8 to 2·2 m−2 and in a cumulative richness per plot of 1·4 to 5·8 m−2.
In both 2001 and 2002 there was a strong, inverse relationship between the frequency of Rhinanthus and sward height. In 2002, there was evidence of a threshold frequency of the hemiparasite above which there was a significant reduction in grassland productivity.
The frequency of Rhinanthus in 2001 had a significant beneficial effect on the persistence of seven of the 10 sown forbs in the following year. This probably reflects a reduction in competition from the established grassland species at the vulnerable seedling stage, together with death of the hemiparasite leading to a higher number of gaps for colonization.
Synthesis and applications. The introduction of R. minor is a practical management tool to facilitate the colonization of species‐poor, productive grasslands by desirable species. This is achieved by the hemiparasite modifying the competitive relationships between the component species, and increasing establishment and survival of introduced species. This species has a potentially central role in determining the structure and dynamics of grassland communities.
Dispersal of adult aquatic insects in catchments of differing land use
Authors: PETERSEN I. , MASTERS Z. , HILDREW A. G. , ORMEROD S. J. 
Published: September 2004

SummaryThere have been widespread changes in land use in the uplands of the UK but the implications for dispersal of adult stages of aquatic invertebrates are poorly known. We estimated the lateral dispersal of adult aquatic insects (Plecoptera, Trichoptera, Ephemeroptera) in seven small, upland streams draining catchments under three categories of land use (coniferous plantation forest, cleared forest, moorland).Malaise traps were set out in transects perpendicular to each stream. More than 29 000 adult insects were taken, distributed among 15 species of stoneflies, 40 species of caddisflies and eight taxa of mayflies. Overall species diversity and equitability were highest in the moorland catchments, and few species were numerous in all catchments.Nearly all the mayflies were taken in the moorland catchments, where caddisflies were also most abundant. Fewest stoneflies were taken in the forested catchments.The vast majority of insects were taken either directly over, or very close to, the stream channel. Half the stoneflies were taken within 18 m of the channel, while 90% had travelled less than 60 m. Caddisflies and mayflies travelled even shorter distances. Although there were differences in lateral dispersal between some catchments, there was no overall effect of land use.The overall sex ratio in stoneflies and mayflies in the riparian zone was close to 1 : 1 and lateral dispersal was similar between the sexes. Male mayflies outnumbered females in the riparian zone and males travelled further from the stream, on average, than females. In catches taken directly over the stream, female stoneflies outnumbered males.Regardless of land use, the flight of mayflies and caddisflies was concentrated along the stream, rather than perpendicular to it. This was also true for two numerous stoneflies (Amphinemura sulcilcollisandProtonemura meyeri) and for female stoneflies overall.Synthesis and applications. The stream corridor, including the riparian strip extending 10–20 m on either side of the channel, is the main habitat for adult aquatic insects, and its management may affect the biodiversity of aquatic communities. The stream corridor is also revealed as the main ‘highway’ for adult dispersal. While there is no evidence from this study of an effect on interstream dispersal of land use elsewhere in the catchment, such an effect cannot yet be refuted because rare long‐distance dispersal events are difficult to record.