bluuebunny/crossref_metadata_2025 huggingface dataset:
Sublethal exposure from microcystins to renal insufficiency patients in Rio de Janeiro, Brazil
Authors: Soares Raquel M. , Yuan Moucun , Servaites Jerome C. , Delgado Alvimar , Magalhães Valéria F. , Hilborn Elizabeth D. , Carmichael Wayne W. , Azevedo Sandra M. F. O.
Published: March 2006

In November 2001, a cyanobacterial bloom dominated by Microcystis and Anabaena occurred in the Funil Reservoir and the Guandu River, both of which supply drinking water to Rio de Janeiro, Brazil. Using ELISA, microcystins were detected at a concentration of 0.4 μg/L in the drinking water, whereas a concentration of 0.32 μg/L was detected in activated carbon column–treated water for use at the renal dialysis center of Clementino Fraga Filho Hospital (HUCFF) at the Federal University of Rio de Janeiro. A total of 44 hemodialysis patients who received care at this center were believed to be exposed. Initial ELISA analyses confirmed the presence of serum microcystin concentrations ≥ 0.16 ng/mL in 90% of serum samples collected from these patients. Twelve patients were selected for continued monitoring over the following 2‐month period. Serum microcystin concentrations ranged from <0.16 to 0.96 ng/mL during the 57 days after documented exposure. ELISA‐positive samples were found throughout the monitoring period, with the highest values detected 1 month after initial exposure. ESI LC/MS analyses indicated microcystins in the serum; however, MS/MS fragmentation patterns typical of microcystins were not identified. LC/MS analyses of MMPB for control serum spiked with MCYST‐LR. and patient sera revealed a peak at retention time of 8.4 min and a mass of 207 m/z. These peaks are equivalent to the peak observed in the MMPB standard analysis. Taken together ELISA, LC/MS, and MMPB results indicate that these renal dialysis patients were exposed to microcystins. This documents another incident of human microcystin exposure during hemodialysis treatment. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 95–103, 2006.
Specific antioxidant reactions to oxidative stress promoted by natural organic matter in two amphipod species from Lake Baikal
Authors: Timofeyev Maxim A. , Shatilina Zhanna M. , Kolesnichenko Aleksey V. , Kolesnichenko Viktoria V. , Steinberg Christian E. W.
Published: March 2006

Aquatic organisms are exposed to a variety of natural chemical stressors such as humic substances. The aim of this study was to investigate the mode of action of natural organic matter (NOM, roughly 80% of which is humic substances) on two freshwater amphipods from Lake Baikal, Eulimnogammarus verrucosus (Gerstf.) and Eulimnogammarus cyaneus (Dyb.), in order to assess the potential oxidative stress of NOM impact. Chosen as oxidative stress markers were lipid peroxidation and cell internal hydrogen peroxide level as well as peroxidase, catalase, and glutathione S‐transferase activities. Exposure of amphipods to NOM caused a significant increase in lipid peroxidation but a concomitant decrease in hydrogen peroxide concentration, and peroxidase and (to a lesser degree) glutathione S‐transferase activities. An interim increase of catalase activity was observed. A possible reason for the decrease in major antioxidant enzyme activity is exhaustion of the reservoir of reduced substrates in the first stage of the antioxidant defense reaction. Despite the inhibition of major antioxidant enzymes, the studied amphipods were able to successfully resist the NOM oxidative impact and, at low NOM concentrations, to combat lipid peroxidation processes. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 104–110, 2006.
Cytotoxicity assessment of gliotoxin and penicillic acid in Tetrahymena pyriformis
Authors: Gräbsch C. , Wichmann G. , Loffhagen N. , Herbarth O. , Müller A.
Published: March 2006

Various studies have documented the associations between mold exposure and effects on health. Mycotoxins, which occur in spores and mold fragments, can be involved in processes that have pathological effects, such as adynamia of the immune system, recurrent infections of the respiratory tract, or asthma. Using Tetrahymena pyriformis, a single‐cell organism well established as a suitable model for human respiratory epithelium‐cell functionalities, we investigated dose–response relationships of the mycotoxins gliotoxin and penicillic acid. Our study focused on the viability (cell count, MTT assay), energy levels (adenosine‐5′‐triphosphate content), energy‐providing processes (MTT reduction per cell), and cell respiration (oxygen consumption). Both mycotoxins acted as cytotoxins in a dose‐dependent manner. Gliotoxin had a stronger inhibitory effect (EC50 0.38 μM) than did penicillic acid (EC50 343.19 μM). The energy‐providing processes were not inhibited or were only weakly inhibited under the influence of gliotoxin, whereas penicillic acid caused stimulation of the physiological parameters. Summarizing the results, it is clear that the two investigated mycotoxins must have different modes of action. They are not only different in the strength of their toxic effects but also in a variety of physiological aspects. In addition, T. pyriformis showed differences in its ability to overcome the negative effects of particular mycotoxin exposures. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 111–117, 2006.
QSARs for aromatic hydrocarbons at several trophic levels
Authors: Di Marzio Walter , Saenz Maria Elena
Published: March 2006

Quantitative structure–activity relationships (QSARs) with aromatic hydrocarbons were obtained. Biological response was measured by acute toxicity of several aquatic trophic levels. The chemicals assayed were benzene, toluene, ethylbenzene,o‐xylene,m‐xylene,p‐xylene, isopropylbenzene,n‐propylbenzene, and butylbenzene. Acute toxicity tests were carried out withScenedesmus quadricauda, as representative of primary producers;Daphnia spinulata, a zooplanctonic cladoceran;Hyalella curvispina,a benthic macroinvertebrate; andBryconamericus iheringii,an omnivorous native fish. The EC50or LC50was calculated from analytical determinations of aromatic hydrocarbons. Nonlinear regression analysis between the logarithm of the octanol–water partition coefficient (logKow) of each compounds and the toxicity end points was performed. QSARs were positively related to increases in logKowat all trophic levels. Intertaxonomic differences were found in comparisons of algae with animals and of invertebrates with vertebrates. We observed that these differences were not significant with a logKowhigher than 3 for all organisms. Aromatic hydrocarbons with logKowvalues of less than 3 showed different toxicity responses, with algae more resistant than fish and invertebrates. We concluded that this was a result of the narcotic mode of action related to liposolubility and the ability of the compound to reach its target site in the cell. The bioconcentration factor (BCF) achieved to start nonpolar narcosis fell almost 1 order of magnitude below the BCF expected from the logKow. Predicted critical body residues for nonpolar narcosis ranged between 2 and 1 mM. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 118–124, 2006.
Microcystins associated with Microcystis dominated blooms in the Southwest wetlands, Western Australia
Authors: Kemp Annabeth , John Jacob
Published: March 2006

Potentially toxic cyanobacterial blooms are becoming common in the freshwater wetlands on the Swan Coastal Plain, Western Australia. During summer the dominant bloom‐causing species belong to the genera Microcystis and Anabaena and to a lesser extent Aphanizomenon and Nodularia. Although toxic cyanobacteria have been recorded in the Swan–Canning and Peel–Harvey estuaries in Western Australia, very little is known about the blooms in the surrounding freshwater lakes. In this study, a total of 32 natural bloom samples representing 13 lakes were analyzed by HPLC for microcystin (MC)–LR, ‐RR, and ‐YR. Twenty‐eight samples proved to be toxic. The highest total microcystin concentration ranged from 1645 to 8428.6 μg L−1, and the lowest concentrations were less than 10 μg L−1 with some below the detection limit (< 0.05 μg L−1). MC‐LR (100%) was the predominant microcystin, followed by MC‐YR (71.4%) and MC‐RR (60.7%). The presence of a Nodularia spumigena bloom in the freshwater Lake Yangebup was associated with the detection of nodularins (1664 μg L−1). This is the first study to demonstrate the presence of microcystins and nodularins in urban lakes on the Swan Coastal Plain, Western Australia. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 125–130, 2006.
Biodegradability testing using standardized microbial communities as inoculum
Authors: Paixão S. M. , Sàágua M. C. , Tenreiro R. , Anselmo A. M.
Published: March 2006

Reference materials are important tools for maintaining high‐quality assurance standards, including for biological materials. A significant number of environmental international standards, including biodegradability and toxicity, involve utilization of activated sludge (AS) inocula. The absence of inoculum standardization in these tests is a potential source of error influencing the results. In this study three defined microbial consortia, two commercial inocula and a designed bacterial inoculum, were evaluated as an AS alternative seed for the Zahn–Wellens test, using diethylene glycol as the reference chemical. The results showed that to achieve diethylene glycol biodegradation with these inocula, a number of 105 colony‐forming units per milliliter of effective degrader microorganisms had to be present. Moreover, the addition of AS supernatant to the test mixtures improved inocula performance (the biodegradability curves), bringing them closer to those obtained with AS inocula. Among the three defined consortia, the designed inoculum replicates bested the AS behavior in the range of concentrations tested, with degradation completed in 12–14 days. Comparisons of the community substrate utilization profiles corroborated these results, showing that the designed inoculum profile was the most similar to the AS profile. The biodegradability and metabolism results provided support for the assertion that the designed inoculum can be used in the Zahn–Wellens test and as a base to develop reference inocula for other biodegradability and toxicity tests. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 131–140, 2006.
Simplified protocol for evaluating the genotoxic risk of hospital wastewater
Authors: Jolibois B. , Guerbet M.
Published: March 2006

To evaluate the genotoxicity of hospital wastewater, we drew up a simplified protocol based on two well‐known tests: the SOS chromotest and the Ames fluctuation test. Three concentrations of wastewater samples were directly tested without extraction or concentration. By fixing three significance levels in genotoxicity response for each test, we could classify the samples in five categories ranging from nongenotoxic to highly genotoxic. This simplified classification thus constitutes an invaluable help in making the nonscientist public aware of the genotoxic risk of hospital wastewater and can be applied in a screening approach to chemicals in the environment. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 141–146, 2006.
Lead toxicity in Brassica pekinensis Rupr.: Effect on nitrate assimilation and growth
Authors: Xiong Zhi‐Ting , Zhao Fei , Li Min‐jing
Published: March 2006

Lead is a major heavy‐metal contaminant in the environment that has various anthropogenic and natural sources. To study the phytotoxic effects of Pb on the popular vegetable Chinese cabbage (Brassica pekinensis Rupr.) via depression of nitrogen assimilation, pot culture experiments with three concentrations of treatment with Pb (0, 4, and 8 mmol/kg dry soil) were carried out. Our results demonstrated adverse effects of Pb on nitrogen assimilation and plant growth. The addition of Pb in the soil resulted in elevated accumulation of Pb in the shoots of the plants: Pb concentrations of 14.3, 202.3, and 418.2 mg/kg (DW) in the shoots were detected with the 0, 4, and 8 mmol/kg treatments, respectively. Compared to the control, Pb exposure (4 and 8 mmol/kg) significantly decreased shoot nitrate content (71% and 80% of the control), nitrate reductase activity (104% and 49% of the control), and free amino acid content (81% and 82% of the control), indicating decreased nitrogen assimilation in the plants. The effect of Pb also was shown by the progressive decline in shoot biomass with increasing Pb concentration in plant shoots and in the soil. However, at the treatment levels used in this study, lead did not induce visible toxic symptoms. The lowest‐concentration Pb treatment (4 mmol/kg) stimulated chlorophyllb content but did not influence chlorophyll a content. The results suggested that the toxicity of Pb to the plants occurred at least partly via depression of nitrogen assimilation. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 147–153, 2006.
Tributyltin induces DNA damage as well as oxidative damage in rats
Authors: Liu Hui‐Gang , Wang Yan , Lian Lingjun , Xu Li‐Hong
Published: March 2006

In this study, oxidative and DNA damage were measured synchronously after Sprague–Dawley rats were exposed to different dosages of tributyltin (TBT) for 3 and 7 consecutive days. Oxidative damage was measured by analyzing the production of hepatic reactive oxygen species (ROS), the activity of superoxide dismutase (SOD), and the content of malondialdehyde (MDA). DNA damage was measured by single‐cell gel electrophoresis (comet assay). After 3 days of exposure, significant differences in ROS production could only be seen between the control and the highest dosage group (10 mg/kg BW d), although after 7 days of treatment, ROS production increased in a dose‐dependent manner. SOD activity increased with dosage after 3 days of exposure and decreased with dosage after 7 days of exposure. TBT also induced significant production of MDA after 7 days of exposure. The changes in ROS, SOD, and MDA found in this study suggest that the antioxidative systems of rats were activated by TBT in the first 3 days of exposure but had become exhausted by 7 days of exposure. In the comet assay, the number of cells with damaged DNA in rats treated with TBT increased with dosage of TBT. The most likely mechanism of the DNA breakage induced by TBT is oxidative damage. It can be concluded that exposure of TBT can promote both oxidative and DNA damage in mammals in vivo. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 166–171, 2006.
Herbage yield and economic viability of grass (Panicum colaratum) and legume (Trifolium prantese) mixtures under variable seed rates in the eastern highlands of Ethiopia
Authors: Tamir Berhan
Published: March 2006

Mixtures of grass (Panicum colaratum) and legume (Trifolium prantese) at seed rates of 50 : 50% produced (p < 0.001) higher herbage dry matter yield and was biologically and economically more competitive and viable than 25 : 75% and 75 : 25%, since it had the highest land equivalent ratio and the best monetary advantage (US$219) and net return (US$144). Copyright © 2006 John Wiley & Sons, Ltd
Biological potential and economic viability of grass (Chloris gayana) and legume (Stylosanthes guianensis) associations under variable seed rates in the eastern highlands of Ethiopia
Authors: Tamir Berhan
Published: March 2006

Association of grass (Chloris gayana) and legume (Stylosanthes guianensis) at seed rates of 50 : 50% produced significantly (p < 0.001) more herbage dry matter yield and was biologically more competitive than 25 : 75%, 75 : 25% or the sole stand, since it had the highest land equivalent ratio and the best monetary advantage (US$240) and net return (US$165). Copyright © 2006 John Wiley & Sons, Ltd
Prediction of intrapartum Cesarean delivery for non‐reassuring fetal status after a successful external cephalic version by a low pre‐version pulsatility index of the fetal middle cerebral artery
Authors: Leung T. Y. , Fok W. Y. , Chan L. W. , Law L. W. , Lau T. K.
Published: March 2006

Objective

To determine whether a pre‐version Doppler assessment of fetal cerebral and umbilical blood flow can predict the ultimate need for intrapartum Cesarean delivery after a successful external cephalic version (ECV).

Methods

A prospective observational study on women undergoing ECV between 36 and 38 gestational weeks was performed over a 5‐year period. The pulsatility index (PI) of the fetal middle cerebral artery (MCA) and umbilical artery, heart rate and amniotic fluid index were measured before ECV. Women who had successful ECV were then divided into three groups according to the mode of delivery: (1) vaginal delivery, (2) intrapartum Cesarean delivery for poor progress and (3) intrapartum Cesarean delivery for non‐reassuring fetal status. The fetal blood flow parameters were compared between the groups. Potential predictors were further analyzed using receiver‐operating characteristics curves.

Results

Of 174 women with successful ECV, 140 (80.5%) had vaginal delivery, 19 (10.9%) required emergency intrapartum Cesarean delivery for non‐reassuring fetal status and 15 (8.6%) for poor progress. MCA‐PI was significantly lower in the group with non‐reassuring fetal status. MCA‐PI is predictive of intrapartum Cesarean delivery (area under the curve = 0.68, P = 0.021). The sensitivity and specificity at a cut‐off level of 1.4 were 62.5% and 76%, respectively, while at a cut‐off level of 1.5 they were 68.8% and 63.5%, respectively.

Conclusion

Intrapartum Cesarean delivery for non‐reassuring fetal status after successful ECV is associated with a lower pre‐version fetal MCA‐PI. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Which extrauterine pelvic masses are difficult to correctly classify as benign or malignant on the basis of ultrasound findings and is there a way of making a correct diagnosis?
Authors: Valentin L. , Ameye L. , Jurkovic D. , Metzger U. , Lécuru F. , Van Huffel S. , Timmerman D.
Published: March 2006

Objectives

To determine which extrauterine pelvic masses are difficult to correctly classify as benign or malignant on the basis of ultrasound findings, and to determine if the use of logistic regression models for calculation of individual risk of malignancy would improve the diagnostic accuracy in difficult tumors.

Methods

In a prospective, international, European multicenter study involving nine centers, 1066 women with a pelvic mass judged to be of extrauterine origin underwent transvaginal ultrasound examination by an experienced ultrasound examiner before surgery. A standardized examination technique and predefined definitions of ultrasound characteristics were used. On the basis of subjective evaluation of ultrasound findings, the examiner classified each mass as being certainly benign, probably benign, unclassifiable, probably malignant or certainly malignant. Even when the examiner found the mass unclassifiable (i.e. difficult mass) he or she was obliged to state whether the mass was more likely to be benign or malignant. Borderline tumors were classified as malignant.

Results

There were 90 (8%) unclassifiable masses. Multiple logistic regression analysis showed papillary projections, >10 locules in a cyst without solid components, low‐level echogenicity of cyst fluid, and moderate vascularization as assessed subjectively at color Doppler examination to be ultrasound variables independently associated with unclassifiable mass. Borderline malignant tumors (n = 55) proved to be most difficult to assess with only 47% being correctly classified (i.e. classified as malignant), 29% being incorrectly classified (i.e. classified as benign) and 24% being unclassifiable vs. 90% of non‐borderline tumors being correctly classified, 3% being incorrectly classified and 8% being unclassifiable (P < 0.0001). Papillary cystadeno(fibro)mas, myomas and cases of struma ovarii were also more common among the unclassifiable masses than among the classifiable ones (5.6% vs. 1.1%, P = 0.008; 4.4% vs. 0.9%, P = 0.02; 4.4% vs. 0.2%, P = 0.0006). No ultrasound variable or clinical variable (including CA 125) entered a logistic regression model to predict malignancy in difficult masses. A model could be constructed for difficult masses containing papillary projections but this model performed no better than subjective evaluation of the ultrasound image. Sensitivity and specificity of subjective evaluation with regard to malignancy in the group of unclassifiable masses were 56% (14/25) and 77% (50/65) vs. 91% (220/241) and 97% (712/735) in the classifiable masses.

Conclusions

Borderline tumors cause great diagnostic difficulties, but so do papillary cystadeno(fibro)mas, struma ovarii and some myomas. Logistic regression models do not solve the diagnostic problem in difficult pelvic masses. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Inter‐ and intraobserver variability in sonographic measurement of the lower uterine segment after a previous Cesarean section
Authors: Jastrow N. , Antonelli E. , Robyr R. , Irion O. , Boulvain M.
Published: March 2006

Objective

To evaluate the reproducibility of sonographic measurement of the lower uterine segment in pregnant women at term.

Methods

Two independent observers performed transabdominal sonography on 129 women between 36 and 38 weeks of gestation who had had a previous Cesarean section. Sonography was performed when the patients had a full and a half‐full bladder; in 100 patients, the measurements were also performed transvaginally, with the patients having an empty bladder. Agreement was quantified by the intraclass correlation coefficient and, using a cut‐off of 3.5 mm, by the kappa coefficient.

Results

The intraobserver agreement was generally high (intraclass correlation coefficient > 0.90). The interobserver agreement was higher on transvaginal (intraclass correlation coefficient, 0.94) compared with transabdominal (0.70 and 0.84, with full and half‐full bladder, respectively) ultrasound. The kappa coefficient was 0.75 transvaginally, compared with 0.34 and 0.54 using the transabdominal approach, with full and half‐full bladder, respectively.

Conclusion

The agreement between two observers for sonographic transvaginal measurement of the lower uterine segment can be considered good, compared with poor to moderate agreement using the transabdominal approach. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Sonographic measurement of cervical length and fetal fibronectin testing in threatened preterm labor
Authors: Tsoi E. , Akmal S. , Geerts L. , Jeffery B. , Nicolaides K. H.
Published: March 2006

Objective

In women presenting with threatened preterm labor, both fetal fibronectin and sonographic measurement of cervical length have been shown to distinguish between true and false labor. The aim of this study was to determine whether the combination of both tests provides a better prediction than the individual tests alone.

Methods

We examined 195 women with singleton pregnancies presenting at 24–36 (median 31) weeks of gestation with regular and painful uterine contractions, intact membranes and cervical dilatation of less than 3 cm. On admission to the hospital fetal fibronectin positivity in cervicovaginal secretions was determined and transvaginal sonographic measurement of cervical length was carried out. The results were not made available to the attending obstetrician. The primary outcome measure was delivery within 7 days of presentation.

Results

Delivery within 7 days occurred in 51.4% (18 of 35) of those with cervical length below 15 mm and 0.6% (1 of 160) of those with cervical length of 15 mm or more, in 21.2% (18 of 85) of the fibronectin positive group and in 0.9% (1 of 110) of the fibronectin negative group. There was a significant association between cervical length and the incidence of fibronectin positivity (r = −0.921, P = 0.003). Logistic regression analysis demonstrated that the only significant contributor to the prediction of delivery within 7 days was cervical length, with no significant contribution from fibronectin positivity, ethnic origin, maternal age, gestational age, body mass index, parity, previous history of preterm delivery, cigarette smoking, or use of tocolytics.

Conclusions

In women with threatened preterm labor assessment of fetal fibronectin in cervicovaginal secretions does not improve the prediction of delivery within 7 days provided by the sonographic measurement of cervical length. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Size and shape analysis of mineral resources in arroyo willow and their relation to sawfly densities
Authors: Boecklen William J. , Mopper Susan , Price Peter W.
Published: March 2006

The association between host‐plant mineral nutrients and insect herbivory is complex, idiosyncratic, and dynamic. Because of this we employed an unusual statistical method to evaluate the relationship between tenthredinid sawfly herbivory and concentrations of foliar nutrients in arroyo willow, Salix lasiolepis. We discovered that among 20 willow clones and between two years arroyo willow varied in the size (absolute concentrations) and shape (relative concentrations) of five mineral nutrients (Ca, Mg, N, P, and K). Similarly, the densities of five sawfly species varied in size and shape among clones and between years. In 1984, relative densities, or shape, of the sawfly community was associated with relative concentrations, or shape, of foliar nutrients in 20 willow clones. In contrast, in 1985 absolute densities, or size, was associated with absolute concentrations, or size, of foliar nutrients. This shift from a shape to a size association between herbivory and foliar mineral nutrients may reflect the large difference in winter precipitation and sawfly densities between years: precipitation and sawfly densities were much greater in 1985 than in 1984.
Vegetative growth and productivity of Eichhornia azurea with special emphasis on leaf dynamics
Authors: Ikusima Isao , Gentil José Geraldo
Published: March 2006

The lifeform and the biological production of pure stands of Eichhornia azurea Kunth in three lakes in tropical Brazil were studied. The lifeform of E. azurea is termed ‘semi‐emergent’, because the plant has well developed trailing stems just under the water, and the aerial lamina emerges with the thick petiole. The density of shoot apices was 9.9, 17.2 and 17.1 m−2 in Lake Dom Helvecio, Lake Jacaré and Lake Carioca, respectively. The mean daily increment of the apical shoot biomass was between 1.8 and 4.8 g m−2 day−1. The mean leaf life‐span in Lake Dom Helvecio, Lake Jacaré and Lake Carioca was estimated to be 78, 49 and 64 days in the wet season and 73, 70 and 73 days in the dry season, respectively. The stem life‐span was estimated to be about 28 months. Starch content in the current years' stem ranged from 24 to 118 mg g−1 dry matter with fluctuations, the amplitude of which decreased with age. The differences for most of the growth parameters, such as density of shoot apices, daily increment of biomass and leaf life‐span, between dry and wet season are smaller than those among the three lakes. Both the decrease in daily dry matter production and the increase in leaf life‐span occurred in order from Lake Dom Helvecio to Lake Jacaré and Lake Carioca. The low productivity of E. azurea is considered to be related to a low leaf area index, a long time interval for the emergence of new leaves, long leaf life‐span and a low capacity for branching.
Intra‐ and interspecific dominance hierarchies and variation in foraging tactics of two species of stream‐dwelling chars
Authors: Nakano Shigeru , Furukawa‐Tanaka Tetsuo
Published: March 2006

Aggressive interactions, foraging behavior, habitat use and diet were studied in sympatric populations of white‐sported char,Salvelinus leucomaenis, and Dolly Varden,Salvelinus malma, in a Japanese mountain stream. Underwater observations on individuals of both species revealed two distinct behavioral regimes: aggressive drift foragers and non‐aggressive benthos foragers. Aggressive drift foragers defended partial territories around focal points from which they made forays to capture invertebrates drifting in the water column. Non‐aggressive benthos foragers cruised around and beneath cobble in large foraging ranges that overlapped each other. Intra‐ and interspecific, size‐dependent dominance hierarchies were recognized among aggressive drift foragers, whereas non‐aggressive benthos foragers showed no such relationships. Terrestrial invertebrates were the most abundant prey in the diets of drift foragers, whereas a very small proportion of the diet of benthos foragers was made up of these taxa. Benthos foragers showed more complex diet composition than drift foragers. These results suggest that non‐aggressive benthos foragers may avoid not only interference but also exploitative competition by using alternative foraging tactics. The proportion of drift foragers to benthos foragers among white‐spotted char was more than 35 times that among Dolly Varden. The significant difference in the proportion of each species using the two types of foraging strategy results in interspecific food segregation in sympatric populations.
Diagnosis and Treatment of Acute Appendicitis in Children: A Survey Among Dutch Surgeons and Comparison with Evidence‐based Practice
Authors: Tan E.C.T.H. , Severijnen R.S.V.M. , Rosman C. , van der Wilt G.J , van Goor H.
Published: March 2006

Background

Considerable variability exists in the surgical approach to acute appendicitis in children, affecting both quality and costs of care. A national survey provides insight into daily surgical practice and enables comparison of practice with the available evidence.

Methods

A national survey was conducted in all 121 Dutch hospitals asking detailed information concerning diagnosis and treatment of children suspected of acute appendicitis. An evidence‐based practice (EBP) score was developed on the basis of a critical appraisal of the literature, allowing for classification of reported practices with regard to the level of evidence and identification of hospitals working in accordance with the best available evidence.

Results

The overall response rate was 93%. For the diagnosis of acute appendicitis, respondents relied predominantly on patient history (29%) and clinical examination (31%), followed by laboratory results (22%). Only 20% of the departments routinely measured total white blood cell count (WBC), C‐reactive protein (CRP) and leukocyte differential count (proportion of polymorphonuclear cells), being part of the triad that provides diagnostic evidence. Although strong evidence exists in favour of routine prophylaxis for suspected appendicitis, only two thirds of surgical departments reported this as part of their routine practice. For a number of issues, reasonably consistent evidence is available (e.g. primarily versus delayed closure, drainage versus lavage, routine peritoneal culturing). Thirty‐eight percent of the departments routinely cultured abdominal fluid despite various reports that it provides no therapeutic advantage. Not more than 22% of the departments closed the skin in perforated appendicitis in spite of clear supportive evidence. Considerable variation exists in cleaning the abdomen in perforated appendicitis, despite evidence favouring lavage. Comparing departments in terms of compliance with available evidence revealed that most paediatric surgery departments worked according to evidence‐based medicine.

Conclusions

Available evidence on diagnosis and treatment of acute appendicitis in children is only partly applied in a small proportion of hospitals in the Netherlands. It is recommended that national guidelines be published, which could decrease health care costs and increase more uniform policy, improve quality of care for this group of patients and improve training of residents in general surgery in the Netherlands.
Cost/DALY Averted in a Small Hospital in Sierra Leone: What Is the Relative Contribution of Different Services?
Authors: Gosselin Richard A. , Thind Amardeep , Bellardinelli Andrea
Published: March 2006

Background

A cost‐effective analysis (CEA) can be a useful tool to guide resource allocation decisions. However, there is a dearth of evidence on the cost/disability‐adjusted life year (DALY) averted by health facilities in the developing world.

Methods

We conducted a study to calculate the costs and the DALYs averted by an entire hospital in Sierra Leone, using the method suggested by McCord and Chowdhury (Int J Gynaecol Obstet 2003;81:83–92).

Results

For the 3‐month study period, total costs were calculated to be $369,774. Using the approach of McCord and Chowdhury, we calculated that 11,282 DALYs were averted during the study period, resulting in a cost/DALY averted of $32.78. This figure compares favorably to other non‐surgical health interventions in developing countries. We found that while surgery accounts for 63% of total caseload, it contributes to 38% of the total DALYs averted.

Conclusions

Surgical treatment of some common pathologies in developing countries may be more cost‐effective than previously thought, and our results provide evidence for the inclusion of surgery as part of the basic public health armamentarium in developing countries. However, these results are highly context‐specific, and more research is needed from developing countries to further refine the methodology and analysis.
Dysphoric adolescents’ causal explanations and expectancies for approach and avoidance goals
Authors: Dickson Joanne M. , MacLeod Andrew K.
Published: March 2006

Relatively little research has studied emotional disturbance from a motivational perspective. The current study aimed to investigate personal goal systems at different levels of analysis, namely, personal goals, associated causal explanations and goal expectancies, as a function of dysphoria. Dysphoric () and non‐dysphoric () adolescents (16–18‐yr‐olds) selected from a larger school sample completed tasks that measured number of approach goals and avoidance goals, causal explanations for goals, and perceived likelihood and control estimates for idiographic goals. As predicted dysphoric adolescents, relative to controls, generated a combination of more avoidance goals and fewer approach goals, and thought of more reasons that explain why goals would not be achieved and fewer reasons that explain why goals would be achieved (irrespective of goal type), and considered avoidance goal outcomes as more likely to occur and approach goal outcomes as less likely to occur. In addition, dysphoric adolescents anticipated less personal control in implementing their goals than controls. Overall, the data identified distinct personal goal systems that function differently in dysphoric and non‐dysphoric adolescents.
Pre-Electoral Coalition Formation in Parliamentary Democracies
Authors: GOLDER SONA NADENICHEK
Published: March 2006

Political parties that wish to exercise executive power in parliamentary democracies are typically forced to enter some form of coalition. Parties can either form a pre-electoral coalition prior to election or they can compete independently and form a government coalition afterwards. While there is a vast literature on government coalitions, little is known about pre-electoral coalitions. A systematic analysis of these coalitions using a new dataset constructed by the author and presented here contains information on all potential pre-electoral coalition dyads in twenty industrialized parliamentary democracies from 1946 to 1998. Pre-electoral coalitions are more likely to form between ideologically compatible parties. They are also more likely to form when the expected coalition size is large (but not too large) and the potential coalition partners are similar in size. Finally, they are more likely to form if the party system is ideologically polarized and the electoral rules are disproportional.
Special Majorities Rationalized
Authors: GOODIN ROBERT E. , LIST CHRISTIAN
Published: March 2006

Complaints are common about the arbitrary and conservative bias of special-majority rules. Such complaints, however, apply to asymmetrical versions of those rules alone. Symmetrical special-majority rules remedy that defect, albeit at the cost of often rendering no determinate verdict. Here what is formally at stake, both procedurally and epistemically, is explored in the choice between those two forms of special-majority rule and simple-majority rule; and practical ways are suggested of resolving matters left open by symmetrical special-majority rules – such as ‘judicial extrapolation’ or ‘subsidiarity’ in a federal system.
Promotion Versus Precaution: The Evolution of Biotechnology Policy in the United States
Authors: SHEINGATE ADAM D.
Published: March 2006

Biotechnology policy in the United States promotes the commercial development of genetically modified crops, yet adopts a precautionary approach when it comes to stem cells and cloning. In this article, the evolution of this bifurcated policy domain is traced. A detailed analysis of congressional hearings shows how distinctions between the products of biotechnology came to be reflected in the character of committees holding hearings, the attention to risks and benefits, and the pattern of interest-group activity in different biotechnology applications. It is argued that many of the differences that separate the United States and Europe in biotechnology reflect the way institutions reinforce past policy choices.
Filling in the Blanks: A New Method for Estimating Campaign Effects
Authors: GEER JOHN , LAU RICHARD R.
Published: March 2006

Scholars have invested a great deal of effort in trying to estimate the impact of political campaigns on the public. While progress has been made, one fundamental problem continues to plague our attempts to study campaigns: the lack of good, detailed data about the behaviour of candidates. In the United States, for instance, the presidential battle is a national struggle that unfolds locally on the stages of fifty states, yet most data collection efforts have treated presidential elections as if they were national contests, conducted (implicitly) in an identical manner across the entire country. Using available (national) data as a baseline and theory to predict plausible variations from that baseline, the authors devise a method for simulating variation in presidential campaigns across states and over election years—one of the crucial missing pieces of the puzzle. Their method generates a range of plausible effects, which is often narrow enough to shed light on important hypotheses. It can be employed whenever data are available at a more aggregate level than is desirable. This method is then applied to assess the debate over the impact of attack advertising on turnout. This approach suggests that campaign negativism stimulated (rather than demobilized) turnout in presidential elections from 1980 through 2000.
Election Laws and Representative Governments: Beyond Votes and Seats
Authors: POWELL G. BINGHAM
Published: March 2006

A sophisticated research tradition has explored theoretically and empirically the consequences of election laws for vote–seat disproportionality and, more recently, for the distance between citizen and legislative left–right medians. In contemporary parliamentary systems, policy making tends to be dominated by governments, not legislatures. This article extends election law theory to its expected effects on the left–right representativeness of governing parties and examines whether these are realized after eighty-two elections in fifteen mature parliamentary systems. The analysis shows how the legislative median party, the legislative plurality party and pre-election coalition agreements between parties shape these connections between citizens, legislatures and governments. The article also develops more nuanced measures of party influence on policy making and re-examines the governmental findings using these. Governments and policy-making configurations emerging from bargaining after PR elections are in net significantly closer to their citizens than those created by SMD elections.
Democracy and Economic Growth: How Regional Context Influences Regime Effects
Authors: KRIECKHAUS JONATHAN
Published: March 2006

There is ongoing controversy as to whether political democracy inhibits or facilitates national economic growth. It is argued here that the answer to this question depends greatly on the regional political context within which democracy functions. In regions where social groups clamour for redistribution, as in Latin America, democracy may lead to populism and poor economic performance. Similarly, in regions where state elites are generally committed to promoting rapid industrialization, as in parts of Asia, democratic pressures may impede effective economic policy. However, in regions where patrimonialism is chronic, as in Sub-Saharan Africa, democracy may provide a useful mechanism for evicting grossly corrupt politicians and may therefore facilitate higher rates of economic growth. These regional arguments are tested statistically here and show that democratic governance constrains growth in Latin America and Asia yet facilitates growth in Africa. Sensitivity analyses indicate that these findings are fairly robust.
Anti-Immigrant Sentiment, Policy Preferences and Populist Party Voting in Australia
Authors: MUGHAN ANTHONY , PAXTON PAMELA
Published: March 2006

Immigration has become a highly salient political issue in many of the world's affluent democracies. Yet, the electoral dynamics of anti-immigrant sentiment remain barely understood. We distinguish two dimensions of concern about immigrants: material threat and cultural threat, and hold that the influence of both on the right-wing populist party vote is critically mediated by policy preferences to restrict immigration and to isolate Australia from foreign influence. The result is a path model of voting that allows material and cultural threat to influence policy preferences about how to deal with the ‘immigrant problem’, and allows both threat and policy preferences to affect voting for the far-right One Nation party in Australia. Our results confirm that popular concern about immigrants is multi-dimensional and that its two dimensions have different sources. We also demonstrate that anti-immigrant sentiment works indirectly through policy orientations to influence vote choice. Feelings about immigrants, in other words, have an electoral effect only when there is a good fit between the policy stances of voters and the policies promoted by the parties on offer.
Globalization and Labour Market Reform: Patterns of Response in Northeast Asia
Authors: KONG TAT YAN
Published: March 2006

The ‘varieties of capitalism’ literature identifies the labour market and labour relations system as an institutional feature by which liberal market economies (LMEs) and co-ordinated market economies (CMEs) of advanced countries may be distinguished. This literature argues for the resilience of CME institutional features to the allegedly convergence-inducing or homogenizing effects of globalization. Resilience to convergence has also revealed different patterns of institutional adaptation to globalizing pressures among CMEs. This article examines the adaptation of labour institutions to globalization using the Northeast Asian Newly Industrialized Countries of South Korea (hereafter Korea) and Taiwan as case studies. Examples are given of how Korea and Taiwan have pursued labour market liberalization, but within institutional conditions (policies and politics) distinct from those associated with transitions to the LME. The origins of this distinctive pattern of response are explained, pointing out the need for explanations based on globalization to be supplemented by ones that emphasize economic legacies and political logics.
An Early Moment in the Discourse of “Terrorism:” Reflections on a Tale from Marco Polo
Authors: Lincoln Bruce
Published: March 2006

My goal in this paper is to revisit a classic text that raises the most contemporary of issues: Marco Polo's stereotyped, highly influential, and highly prejudicial description of the “Old Man of the Mountain,” a text of virtually mythic status and power. Having invoked the category of “myth,” however, in a context where it is not commonly applied, it is useful to indicate how I use this term and why it seems appropriate. To begin, I would reject three widely accepted notions. First, myths are not sacred narratives. Although many myths claim sacred status, in this they misrecognize their own nature, for they are human stories, like any other. They simply make more exaggerated claims to a more elevated kind of authority. Second, myths are not collective narratives or the speech of any group as a whole. Rather, they are stories that are told and retold in countless variants. Often the authorship of these variants is unacknowledged, forgotten, or deliberately hidden, but in its details each variant advances the specific interests of those responsible for its production, revision, and circulation. These anonymous agents and absent authors misrepresent themselves—and those for whom they speak—as the group as a whole. Third, myths are neither false stories, nor true, but simply stories that claim to speak with authority about issues of deep importance. Sometimes these claims succeed and sometimes they fail, and the same story can change its status over time from myth to fable and back again, since such status is a function of reception.
Columbus's Ultimate Goal: Jerusalem
Authors: Delaney Carol
Published: March 2006

The Quincentennial of Columbus's Discovery of the Americas has come and gone. Some people celebrated, others protested. The Discovery has been called either “The greatest event since the creation of the world, save the incarnation and death of Him who created it” (Francisco Lopez de Gomera writing in 1552), or the greatest disaster in world history. Columbus is either a saint (who was actually proposed for canonization), or he is a sinner responsible for genocide. Can one even say that Christopher Columbus discovered America when there were already millions of people living in these lands? Did he discover America when he thought he had found a new route to Asia? The debates are interminable and the issues have become so politicized that an informed and informative discussion has been all but impossible; one steps warily into the fray. Yet, despite the voluminous literature by and about Columbus, Americans outside the rarefied circle of Columbus scholars still know little about the man and his mission. In this paper I discuss some of the little known religious beliefs that underpinned the “Enterprise of the Indies,” for I think they have the potential to change fundamentally our assessment of Columbus and relocate some of the responsibility for the consequences of the encounter.