bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphate limitation influences the sensitivity to copper in periphytic algae
Authors: Guasch Helena , Navarro Enrique , Serra Alexandra , Sabater Sergi 
Published: March 2004

Summary1. To assess the influence of nutrient limitation on copper toxicity, periphitic communities from an oligotrophic stream were exposed to copper for six to 12 days with and without the supply of nutrients (mainly P).2. In contrast to the hypothesis that nutrient cycling in mature biofilms would protect them from Cu toxicity, low and high biomass biofilms did not differ in their physiological response to copper after 6 days of exposure.3. A clear influence of P‐limitation on copper toxicity was observed. Periphytic communities that were previously fertilised for 18 days were three times more tolerant than control communities indicating that P‐limitation enhanced Cu toxicity and tolerance induction were probably related to the higher P‐availability. In addition, a compensation of Cu toxicity after P‐addition was observed in the long‐term (after 12 days).4. We conclude that periphyton from oligotrophic streams is more sensitive to copper than periphyton from fertilised streams, and that therefore a higher effect of chronic copper exposure is expected to occur in oligotrophic P‐limited fluvial systems.5. Extrapolation of our results to the area of study (Catalonia, north‐east of Spain) indicates that while the levels of Cu commonly found in the zone may negatively affect the periphyton from oligotrophic streams, because of the interaction between Cu and P, they are not able to control the growth of nuisance algae which is common under high nutrient conditions.
The effects of macroinvertebrate taxonomic resolution in large landscape bioassessments: an example from the Mid‐Atlantic Highlands, U.S.A.
Authors: Waite Ian R. , Herlihy Alan T. , Larsen David P. , Urquhart N. Scott , Klemm Donald J. 
Published: March 2004

Summary1. During late spring 1993–1995, the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) sampled 490 wadeable streams in the mid‐Atlantic Highlands (MAH) of the U.S. for a variety of physical, chemical and biological indicators of environmental condition. We used the resulting data set to evaluate the importance of differing levels of macroinvertebrate taxonomic resolution in bioassessments by comparing the ability of family versus genus to detect differences among sites classified by type and magnitude of human impact and by stream size. We divided the MAH into two physiographic regions: the Appalachian Plateau where mine drainage (MD) and acidic deposition are major stressors, and the Ridge and Valley where nutrient enrichment is a major stressor. Stream sites were classified into three or four impact classes based on water chemistry and habitat. We used stream order (first to third Strahler order) in each region as a measure of stream size. Ordination, 2 × 2 chi‐square and biotic metrics were used to compare the ability of family and genus to detect differences among both stressor and size classes.2. With one notable exception, there were only a small number of different genera per family (interquartile range = 1–4). Family Chironomidae, however, contained 123 different genera. As a result, significant information loss occurred when this group was only classified to family. The family Chironomidae did not discriminate among the predefined classes but many chironomid genera did: by chi‐square analysis, 10 and 28 chironomid genera were significant in discriminating MD and nutrient impacts, respectively.3. Family and genus data were similar in their ability to distinguish among the coarse impacts (e.g. most severe versus least severe impact classes) for all cases. Though genus data in many cases distinguished the subtler differences (e.g. mixed/moderate impacts versus high or low impacts) better than family, differences in significance levels between family and genus analyses were relatively minor. However, genus data detected differences among stream orders in ordination analyses that were not revealed at the family level. In the ordinations, both family and genus levels of analysis responded to similar suites of environmental variables.4. Our results suggest that identification to the family level is sufficient for many bioassessment purposes. However, identifications to genus do provide more information in genera‐rich families like Chironomidae. Genus or finer levels of identification are important for investigating natural history, stream ecology, biodiversity and indicator species. Decisions about the taxonomic level of identification need to be study specific and depend on available resources (cost) and study objectives.
Inter‐population dispersal by adult stoneflies detected by stable isotope enrichment
Authors: Briers Robert A. , Gee John H. R. , Cariss Helen M. , Geoghegan Rory 
Published: March 2004

Summary1. Dispersal of adult stream insects may be of considerable importance in regional population dynamics and colonisation of new sites, but quantifying the rate and extent of dispersal is difficult.2. We used stable isotope (15N) enrichment to mark more than 1.5 million larval stoneflies (Leuctra inermis) before they emerged from an upland stream in the Plynlimon area of mid‐Wales, in order to determine directly the rate and pattern of inter‐site dispersal.3. A small number of isotopically enriched adult stoneflies were captured in samples taken at adjacent streams between 800 m and 1.1 km away from the source population, including a headwater of a different river system.4. The distribution of marked individuals suggested that wind influences dispersal direction in the uplands, but the low number of captures limits our ability to draw firm conclusions.5. This is the first direct demonstration of dispersal of insects between streams. The dispersal distances recorded were significantly greater than those suggested by previous direct studies, but much more consistent with indirect studies based on genetic differentiation of populations.
Impact of fish predation on cladoceran body weight distribution and zooplankton grazing in lakes during winter
Authors: Jeppesen Erik , Jensen Jens Peder , Søndergaard Martin , Fenger‐Grøn Morten , Bramm Mette E. , Sandby Kjeld , Møller Poul Hald , Rasmussen Helle Utoft 
Published: March 2004

Summary1. It is well accepted that fish, if abundant, can have a major impact on the zooplankton community structure during summer, which, particularly in eutrophic lakes, may cascade to phytoplankton and ultimately influence water clarity. Fish predation affects mean size of cladocerans and the zooplankton grazing pressure on phytoplankton. Little is, however, known about the role of fish during winter.2. We analysed data from 34 lakes studied for 8–9 years divided into three seasons: summer, autumn/spring and winter, and four lake classes: all lakes, shallow lakes without submerged plants, shallow lakes with submerged plants and deep lakes. We recorded how body weight of Daphnia and then cladocerans varied among the three seasons. For all lake types there was a significant positive correlation in the mean body weight of Daphnia and all cladocerans between the different seasons, and only in lakes with macrophytes did the slope differ significantly from one (winter versus summer for Daphnia).3. These results suggest that the fish predation pressure during autumn/spring and winter is as high as during summer, and maybe even higher during winter in macrophyte‐rich lakes. It could be argued that the winter zooplankton community structure resembles that of the summer community because of low specimen turnover during winter mediated by low fecundity, which, in turn, reflects food shortage, low temperatures and low winter hatching from resting eggs. However, we found frequent major changes in mean body weight of Daphnia and cladocerans in three fish‐biomanipulated lakes during the winter season.4. The seasonal pattern of zooplankton : phytoplankton biomass ratio showed no correlation between summer and winter for shallow lakes with abundant vegetation or for deep lakes. For the shallow lakes, the ratio was substantially higher during summer than in winter and autumn/spring, suggesting a higher zooplankton grazing potential during summer, while the ratio was often higher in winter in deep lakes. Direct and indirect effects of macrophytes, and internal P loading and mixing, all varying over the season, might weaken the fish signal on this ratio.5. Overall, our data indicate that release of fish predation may have strong cascading effects on zooplankton grazing on phytoplankton and water clarity in temperate, coastal situated eutrophic lakes, not only during summer but also during winter.
Latest Miocene and Pleistocene ages of faulting, determined by 40Ar/39Ar single‐crystal dating of airfall tuff and silicic extrusives of the Erciyes Basin, central Turkey: evidence for intraplate deformation related to the tectonic escape of Anatolia
Authors: Jaffey Noah , Robertson Alastair , Pringle Malcolm 
Published: March 2004

AbstractThe Ericiyes Basin is a trans‐tensional basin situated 20 km north of the regional Ecemiş Fault Zone. Recently it has been hypothesized that faulting within the Erciyes Basin links with the Ecemiş Fault Zone further south as part of a regional Central Anatolian Fault Zone. New 40Ar/39Ar dating of volcanic and volcaniclastic rocks adjacent to faults, both along the margins and in the centre of the Erciyes Basin, constrains the timing of basin inception and later faulting. Extensional faulting occurred along the eastern and western margins of the basin during the Early Messinian (latest Miocene). Sinistral and minor normal faulting were active along the axis of the basin during the early Pleistocene. These fault timings are similar to those inferred for the Ecemiş Fault Zone further south, and support the hypothesis that faulting within the Erciyes Basin and the Ecemiş Fault Zone are indeed linked.
Stable isotope evidence for magmatic fluid input during large‐scale Na–Ca alteration in the Cloncurry Fe oxide Cu–Au district, NW Queensland, Australia
Authors: Mark Geordie , Foster Damien R. W. , Pollard Peter J. , Williams Patrick J. , Tolman Justin , Darvall Michael , Blake Kevin L. 
Published: March 2004

AbstractSodic–calcic alteration is common in mineralized hydrothermal systems, yet the relative importance of igneous vs. basinal fluid sources remains controversial. One of the most extensive volumes of sodic–calcic rocks occurs near Cloncurry, NW Queensland, and was formed by overlapping hydrothermal systems that were active synchronously with emplacement of mid‐crustal batholithic granitoids (c. 1.55–1.50 Ga). Altered rocks contain albite–oligoclase, actinolite, diopside, titanite and magnetite. Alteration was localized by: (A) composite veins and breccias containing crystallized magma intimately intergrown with hydrothermal precipitates; (B) intrusions that host setting A veins and breccias; and (C) extensive breccia and vein systems linked to regional fault systems. Isotope analyses of actinolites in settings A and B indicate calculated δ18OH2O (+8.2 to +10.6‰) and variably depleted δDH2O (−130 to −54‰) compared with typical magmatic fluids, whereas those from setting C typically indicate calculated δ18OH2O (+8.0 to +12.8‰) and δDH2O (−29 to −99‰). The lowest δDH2O values are interpreted as representing residual fluids after significant (> 90%) open‐system magmatic degassing. Overall the stable isotope, field, geochronological and geobarometric data suggest that these sodic–calcic alteration systems were formed by the episodic incursion of magmatic fluids that underwent minor isotopic modification as a result of varying degrees of interaction with country rocks.
SHRIMP U–Pb zircon dating of quartz‐bearing eclogite from the Sanbagawa Belt, south‐west Japan: implications for metamorphic evolution of subducted protolith
Authors: Okamoto Kazuaki , Shinjoe Hironao , Katayama Ikuo , Terada Kentaro , Sano Yuji , Johnson Simon 
Published: March 2004

AbstractIn order to decipher the origin of eclogite in the high‐P/T Sanbagawa metamorphic belt, SHRIMP U–Pb ages of zircons from quartz‐bearing eclogite and associated quartz‐rich rock (metasandstone) were determined. One zircon core of the quartz‐rich rock yields an extremely old provenance age of 1899 ± 79 Ma, suggesting that the core is of detrital origin. Eight other core ages are in the 148–134 Ma range, and are older than the estimated age for trench sedimentation as indicated by the youngest radiolarian fossil age of 139–135 Ma from the Sanbagawa schists. Ages of metamorphic zircon rims (132–112 Ma) from the quartz‐rich rock are consistent with metamorphic zircon ages from the quartz‐bearing eclogite, indicating that eclogite facies metamorphism peaked at 120–110 Ma. These new data are consistent with both the Iratsu eclogite body and surrounding highest‐grade Sanbagawa schists undergoing coeval subduction‐zone metamorphism, and subsequent re‐equilibration under epidote amphibolite facies conditions during exhumation.
Dating of coal fires in Xinjiang, north‐west China
Authors: Zhang Xiangmin , Kroonenberg Salomon B. , De Boer Cor B. 
Published: March 2004

AbstractCoal fires in China consume vast amounts of fuel and cause serious environmental problems. Most of these coal fires are related to mining activity. However, naturally produced palaeo coal fires in Xinjiang, north‐west China, have been recognized via burnt rocks. The burnt rocks in the study area are found at different river terraces underlying unburnt alluvial and river terrace deposits. Several age groups of coal fires have been identified based on the positions of burnt rocks at river terraces and the relationship between the burnt rocks and the terrace deposits. These palaeo coal fires are: (1) Pliocene – Early Quaternary in age at 200 m above present river terrace deposits; (2) Middle Pleistocene in age, at > 90 m; (3) Late Pleistocene, at 90–70 m; (4) Holocene; (5) burnt rocks relating to active coal fires. Palaeomagnetic data of the burnt rocks from different terraces give normal remanent magnetization and help further to constrain the ages of the coal fires.
Palaeoproterozoic arc magmatism and collision in Liaodong Peninsula (north‐east China)
Authors: Faure Michel , Lin Wei , Monié Patrick , Bruguier Olivier 
Published: March 2004

AbstractIn the north‐eastern part of the North China Block, a mafic magmatic belt consisting of mafic–ultramafic rocks and marine sedimentary rocks crops out between the northern Archean Anshan Block and a southern Palaeoproterozoic Block. 40Ar/39Ar amphibole ages around 1.9 Ga from gabbros, and trace element analyses of gabbros, pyroxenite and shale show that these rocks formed along a Palaeoproterozoic active continental margin. The mafic magmatic belt is interpreted as an arc developed above a south‐directed subduction zone, which was subsequently overthrust to the north upon the Anshan Archean Block. This study provides a new example agreeing with increasing evidence supporting plate mobility and thrust tectonics during the Palaeoproterozoic. These new insights must be considered with regard to the formation of the North China Block by magmatic accretion and tectonic collision.
Seroprevalence of Sarcosystis spp. in Cattle and Buffaloes from the Wet and Dry Zones of Sri Lanka: a Preliminary Study
Authors: Kalubowila D. G. W. , Udagama‐Randeniya P. V. , Perera N. A. N. D. , Rajapakse R. P. V. J 
Published: March 2004

SummaryAn enzyme‐linked immunosorbent assay (ELISA) was developed for the detection of antibodies to Sarcosystis infection in cattle and buffaloes. Crude antigens derived from cystozoites of Sarcosystis cruzi and antibodies from the sera of naturally infected cattle and buffaloes were used. The assay was validated by determination of the specificity, sensitivity and negative and positive predictive values. Using ELISA, a sero‐epidemiological survey for sarcosystosis was carried out in cattle (n = 215) and buffaloes (n = 123) from the wet and dry zones of Sri Lanka. The prevalence of infection in cattle was 69.3%. Prevalence of the infection collectively in both cattle and buffaloes in the dry zone was significantly higher (P < 0.001) than that in the wet zone. The number of sero‐positive cattle and buffaloes in the dry zone was significantly higher than that in the wet zone (P < 0.05). Buffaloes in the dry and wet zones showed a greater prevalence of infection (P < 0.05) than cattle.
An Enzyme‐Linked Immunosorbent Assay (ELISA) for Detection of Marek's Disease Virus‐Specific Antibodies and its Application in an Experimental Vaccine Trial
Authors: Zelnik V. , Harlin O. , Fehler F. , Kaspers B. , Göbel T. W. , Nair V. K. , Osterrieder N. 
Published: March 2004

SummaryAn enzyme‐linked immunosorbent assay (ELISA) for the detection of Marek's disease virus (MDV)‐specific antibodies was developed. Chicken embryo cells (CEC) or chicken kidney cells (CKC) were infected with MDV vaccine strain CVI988/Rispens, and infected‐cell lysates were prepared at day 5 post‐infection by freeze‐thawing. Uninfected‐cell lysates served as negative controls. Sera were used at a 1 : 100 dilution and were added in parallel to wells containing the infected and uninfected cell lysates. The optical densities at 492 nm (OD492 nm) were measured after detection of bound chicken antibodies with anti‐chicken IgG peroxidase conjugate and colour reactions using o‐phenylenediamine (OPD) as a substrate. The best results concerning the signal‐to‐noise ratio were obtained by using CKC cells rather than CEC for antigen preparation. The OD492 nm of plasma or serum samples with infected CKC was <0.02 when samples of unvaccinated and unchallenged maternal antibody‐negative white leghorn chickens were tested. Sera and plasma samples of positive control birds exhibited OD492 nm of <0.01 when tested with uninfected CKC. The assay was used to monitor a trial that compared experimental BAC DNA vaccines and a commercial vaccine. Sustained seroconversion and antibody titers that were constantly rising until day 84 after vaccination (71 days after challenge) was observed only when chickens did not develop Marek's disease. In contrast, chickens developing the disease mounted marginal and short‐lived antibody titers only. We conclude that the developed ELISA may be a valuable tool for the evaluation of the efficacy of MDV vaccination under experimental but possibly also under field conditions.
Non‐O157 Shiga Toxin‐producingEscherichia coliIsolated from Diarrhoeic Calves in Argentina
Authors: Mercado E. C. , Gioffré A. , Rodríguez S. M. , Cataldi A. , Irino K. , Elizondo A. M. , Cipolla A. L. , Romano M. I. , Malena R. , Méndez M. A. 
Published: March 2004

SummaryFaecal samples from 76 diarrhoeic calves belonging to 36 farms located in the Pampas plain, Argentina, were examined for Shiga toxin‐producingEscherichia coli(STEC). A total of 15 STEC strains were isolated from 12 (15.8%) calves which came from six different farms. Allstxpositive strains assayed by PCR were also positives in the Vero cell cytotoxicity test. The majority (60.0%) of the STEC strains carried thestx1gene. Twelve (80.0%) of the STEC isolates which belonged to serotypes O5:H‐ (n = 4), O26:H11 (n = 4), O26:H‐ (n = 1), O111:H‐ (n = 2), and O123:H38 (n = 1) were also enterohaemolysin (EHly) positive and carried the gene encoding for intimin (eae). All thestxpositive strains were negative for thebfpAgene. Localized adherence to HEp‐2 cells were observed in 83.3% of theeae+ STEC strains. STEC belonging to serotype O5:H‐ showed atypical biochemical properties, including urease production. Urease was also produced by two strains belonging to serotypes O153:H? and non‐typeable, respectively. Resistance to three or more antibiotics was observed in 12 (80.0%) of the STEC isolates. Most of the serotypes of STEC recovered in this survey carried virulence traits that are associated with increased human and bovine pathogenicity. The present study shows that highly virulent STEC strains are being shed by diarrhoeic calves from farms located in a high incidence area of human STEC infections.
Outpatient upper gastrointestinal endoscopy: large, prospective study of the morbidity and mortality rate at a single endoscopy unit in England
Authors: Abbas Syed Z , Shaw Steve , Campbell Diane , George David K , Lowes John R , Teague Robin H 
Published: March 2004

Background:  There are few prospective studies that look at the standards of the practice of esophago‐gastroduodenoscopy (EGD) and its associated morbidity.Patients and methods:  Data were recorded prospectively for 1287 consecutive day‐case diagnostic EGD procedures. Thirty days later, 1155 of 1287 patients were successfully contacted.Results:  The standards of care, as per various national recommendations, were met. Seven hundred and fifty‐four patients (401/572 [70%] men; 353/715 [49%] women; P = 0.001) chose pharyngeal anesthesis (PA) as premedication. Two women had general anesthesia. There were no immediate clinical complications. Thirty days later, 119/1155 (10%) patients who were contacted reported a problem, one requiring hospital admission. Fifty‐one of 119 had EGD performed under midazolam sedation (MS). Twenty‐five of 119 patients required consultation with a health‐care professional. No death occurred. Seventy‐nine percent of patients contacted who underwent their procedure with PA compared with 95% who had MS, said they would prefer the same premedication if EGD was required again in the future (P = 0.001). In subjects who had PA, 25% of women and 12% of men said they would prefer MS if EGD were required again (P = 0.001).Conclusions:  Diagnostic EGD is a safe procedure, but carries a small complication rate. Patients’ gender, age, or patients’ preference for sedation or endoscopist did not affect the morbidity rate. Although the majority, particularly men, chose to have EGD performed unsedated, a significant number, particularly women, would prefer MS if EGD was required again.
Efficacy and long‐term outcome of laparoscopic microwave coagulation or radiofrequency ablation therapy for surface‐type hepatocellular carcinoma
Authors: Tsuji Kunihiko , Nishimori Hiroyuki , Sakurai Yasuo , Mitsui Shinya , Miyamoto Noriyuki , Matsunaga Takahiro , Kang Jong‐Hon , Maguchi Hiroyuki , Maekubo Hiroshi 
Published: March 2004

Background:  Microwave or radiofrequency ablation therapy has been widely perfomed for hepatocellular carcinoma (HCC). Whereas ablation therapy is effective treatment, it cannot be perfomed easily, as is evident in several reports of severe complications. We treated surface‐type HCC under laparoscopy in avoidance of complications from March 1996. In the present study, we examined the efficacy and long‐term outcome of laparoscopic ablation therapy.Patients and Methods:  The patients were 47 cases (58 lesions) of HCC treated by laparoscopic ablation therapy under general anesthesia in our Center from March 1996 until March 2003.Results:  The surface‐type HCC to which the therapy was applicable accounted for approximately 15% of all cases. The overall 5‐year survival rate was 62%. Hepatic reserve and rate of intrahepatic recurrences in the remnant liver after curative treatment were the limiting factors on the survival rate. There was no serious complication in the treatment. It was well tolerated and brought about good quality of life.Conclusion:  Laparoscopic ablation therapy was considered to be an easy and effective approach, and its utility was also recognized in the avoidance of the problems of percutaneous treatment, such as bleeding or damage to the adjacent organs.