bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Body Size on the Responses of Fathead Minnows, Pimephales promelas, to Damselfly Alarm Cues
Authors: Mirza Reehan S. , Chivers Douglas P. 
Published: August 2003

AbstractA wide diversity of aquatic organisms release chemical alarm cues upon encountering or being attacked by a predator. These alarm cues can be used by nearby individuals to assess local predation risk. Receivers warned by chemical alarm cues gain a survival benefit when encountering predators. Animals that are in the same prey guild (i.e. that co‐occur and share the same predators) may learn to recognize each others’ chemical alarm cues. This ability may confer an adaptive advantage if the prey animals are vulnerable to the same predators. However, if the prey grow to different sizes and as a consequence are no longer vulnerable to the same suite of predators, then there should no longer be an advantage for the prey to respond to each others’ alarm cues. In this study, we exposed small and large fathead minnows (Pimephales promelas) to cues from syntopic injured damselfly larvae (Enallagma boreale), cues from injured mealworm larvae (Tenebrio molitor) and to distilled water. Small minnows exhibited antipredatory behaviour and increased shelter use in response to injured damselfly cues but not to the controls of injured mealworm or distilled water. On the contrary, large minnows exhibited no significant change in shelter use in response to any of the injured cues. These data demonstrate that fathead minnows exhibit an antipredator response to damselfly alarm cues, but only when minnows are small and members of the same prey guild as damselfly larvae. These results demonstrate the considerable flexibility in the responses to heterospecific alarm cues.
Response of the foraging behaviour of red wood ants (Formica rufa group) to exclusion from trees
Authors: Lenoir L. 
Published: August 2003

Abstract 1 Because of the large numbers within a colony and their aggressive nature, red wood ants (Formica rufa group) have a potential to greatly influence the cold‐temperate forest ecosystem. Wood ants are omnivorous and hunt in trees as well as on the forest floor.2 A field experiment in a mixed forest in central Sweden was carried out to examine (i) the foraging behaviour of wood ants on the forest floor and (ii) the impact of increased numbers of wood ants on the soil fauna. The foraging behaviour of wood ants was manipulated by excluding the ants from their food resources in the tree canopy, with the intention to increase ant activity on the forest floor. To estimate this activity, the number of trees with foraging ants, the numbers of ants going to and from their nests and the prey carried by home‐running wood ants were determined during the summer period. Pitfall traps were placed in the soil to determine effects on mobile soil invertebrates.3 When excluded from local trees, wood ants searched other trees further away from the nests rather than searching more intensively for prey on the forest floor. By contrast to the initial hypothesis, more soil‐living prey were caught by ants in the control plots than in the plots where the local trees were not accessible to the wood ants. The proportion of soil‐living to tree‐living prey tended to be greater in the control plots.4 In the treated plots (no access to the trees), wood ants had a negative effect on the activity of Linyphiidae spiders. There was little effect of wood ants on other soil invertebrates.5 This study suggests that the role of wood ants as top predators in the forest soil food‐web in central Sweden is limited.
Non‐target habitat exploitation by Trichogramma brassicae (Hym. Trichogrammatidae): what are the risks for endemic butterflies?
Authors: Babendreier D. , Schoch D. , Kuske S. , Dorn S. , Bigler F. 
Published: August 2003

Abstract 1 Trichogramma brassicae Bezdenko is inundatively released against the European corn borer in Switzerland. Because parasitoids dispersing from the release fields might pose a threat to native butterflies, the searching efficiency of T. brassicae was investigated in nontarget habitats.2 In field studies, T. brassicae was released at rates of 120 000 females/ha. Parasitism of sentinel Ephestia kuehniella egg clusters was 1.6–3.6% in meadows and 2.0–4.0% in flower strips. The respective figures were 57.6–66.7% and 19.2–46.9% in maize, significantly higher than the parasitism rates in the nontarget habitats. Experiments carried out in small field cages confirmed these results: Again, significantly higher parasitism rates were found in maize compared to meadows and flower strips, and also compared to hedgerows (in sleeve cages).3 To elucidate potential factors underlying the low searching efficiency in nontarget habitats, the behaviour of individual T. brassicae females was investigated on four meadow plants comparatively to maize and a filter paper control. Mean (±SE) walking speed on maize was 2.2 ± 0.2 mm/s, similar to three of the plants tested and filter paper but significantly higher than on Trifolium pratense (0.85 mm/s). A higher turning rate was found on T. pratense, Viola wittrockiana and Plantago lanceolata, in contrast to the longer leaved maize and Alopecurus pratensis. The number of wasps leaving the plant within the observation period differed significantly between plant species, and was twice as high for T. pratense (and the filter paper control) compared to the other plant species.4 In a choice experiment carried out in a climate cabinet with all five host plant species in cages, we obtained the highest parasitism rates on maize and the lowest parasitism on T. pratense, thus confirming the behavioural observations.5 In conclusion, there is evidence for a decreased searching efficiency on plants in nontarget habitats compared to maize. However, the data explain only part of the differences found between parasitism in maize compared to nontarget habitats. Other factors, such as the structural complexity of a habitat, may also play a role. We conclude that the risk for butterfly populations in the tested nontarget habitat due to mass released T. brassicae is low.
Shoot damage by Tomicus sp. (Coleoptera: Scolytidae) and effect on Pinus yunnanensis resistance to subsequent reproductive attacks in the stem
Authors: Lieutier François , Ye Hui , Yart Annie 
Published: August 2003

Abstract  1 In South‐western China, Yunnan pines Pinus yunnanensis, suffer considerable damage from an undescribed Tomicus sp. previously thought to be T. piniperda.2 To assess the effect of shoot maturation feeding (during which an aggregation process appears to occur) on host resistance to attacks on the bole, the relationships between shoot damage, bole attack density and tree survival were studied.3 Attack distribution in the crown and in the stem did not vary between killed and surviving trees, indicating that mortality is determined by the quantity of attacks.4 The level of shoot damage and bole attack density were positively and linearly correlated. This can be explained by the fact that bole attacks are caused by beetles coming from the crown of the same tree.5 A critical threshold of bole attack density (around 80 attacks/m2) above which trees die was observed. However, because attacks continue after this threshold is reached, the density of failed attacks on the killed trees was used as an estimator of the threshold density. It decreased when shoot damage increased.6 The existence of a critical threshold of shoot damage (60% damaged shoots) was also demonstrated. Above this threshold, stem attack density was always sufficiently high to kill trees.7 The results emphasize that concentration of shoot attacks is the main reason for the extensive tree damage observed in China.8 A model of relationships between shoot and stem attacks is proposed, suggesting that management to reduce shoot attacks would protect trees from dying by both decreasing the number of bole attacks and raising the threshold for successful attack density on the bole to levels that could not be attained.
Sprayable pheromone for controlling the North American grape berry moth by mating disruption
Authors: Trimble R. M. , Vickers P. M. , Nielsen K. E. , Barinshteyn G. 
Published: August 2003

Abstract  1 Sex pheromone‐mediated mating disruption can be used to provide economic control of the North American grape berry moth in commercial vineyards. Controlled release devices that use a plastic tube or polymer to regulate the emission of pheromone have been registered for use in Canada for controlling this pest. These dispensers require manual application, whereas a newly developed microencapsulated formulation can be applied using a vineyard airblast sprayer.2 The efficacy of 3M Sprayable Pheromone was compared with the efficacy of Isomate® GBM pheromone dispensers and organophosphorus insecticide for controlling the grape berry moth during the 1997 and 1998 growing seasons. Two application schedules of sprayable pheromone were tested during 1997 and two formulations of sprayable pheromone were tested during 1998. The mating disruption efficiency of the pheromone treatments was compared using pheromone‐baited traps and the efficacy of the pheromone and insecticide treatments was compared by inspecting grape clusters for feeding injury caused by grape berry moth larvae.3 The estimated mating disruption efficiency of the pheromone treatments ranged from 67 to 100%. There was no difference in the efficiency of the two application schedules of 3M Sprayable Pheromone during 1997. The estimated efficiency of Isomate® GBM was greater than that of 3M Sprayable Pheromone during the first two flights of 1997. During 1998, the estimated efficiency of 3M Sprayable Pheromone and Isomate® GBM was similar.4 The average percentage of grape clusters with grape berry moth feeding injury was greater in the border than in the interior zone on 13 ocassions, and greater in the interior zone than in the border zone of experimental plots on six of the 72 occasions when clusters were inspected during the 2‐year study.5 The average percentage of grape clusters with feeding injury was similar in plots treated with 3M Sprayable Pheromone, Isomate® GBM and insecticide during both years of the study. There was no difference in feeding injury in plots treated with 3M Sprayable Pheromone and Isomate® GBM, despite the greater estimated mating disruption efficiency of Isomate® GBM.6 The use of sprayable pheromone may have several operational and cost advantages compared with a hand‐applied dispensing system such as Isomate® GBM.
Clinical response to alefacept: results of a phase 3 study of intramuscular administration of alefacept in patients with chronic plaque psoriasis
Authors: Ortonne J‐P 
Published: August 2003

ABSTRACTBackground Recognition of psoriasis as a T‐cell‐mediated immune disease has led to the development of various therapeutic approaches directed against the pathogenic T cells. Alefacept, a novel and selective biological recombinant protein, binds CD2 on T cells to block T‐cell activation and proliferation and interacts with FcγRIII receptors on accessory cells to produce selective T‐cell apoptosis.Objective To demonstrate the efficacy and safety of once‐weekly alefacept IM compared with placebo given for 12 weeks to patients with chronic plaque psoriasis.Methods Multicentre (63 sites in Europe, the USA, and Canada), randomized, double‐blind, parallel‐group study comparing 10 mg and 15 mg of alefacept and placebo administered IM once weekly for 12 weeks. Patients were followed for an additional 12 weeks after cessation of therapy. Patients were eligible for enrolment if they were ≥ 18 years of age, had chronic plaque psoriasis for ≥ 12 months involving ≥ 10% body surface area, and had CD4+ T‐cell counts at or above the lower limit of normal.Results 507 patients were enrolled into three treatment groups, which were well balanced for demographic, baseline disease characteristics, and treatment history. A significantly greater percentage of patients treated with alefacept 15 mg IM achieved ≥ 75% PASI reduction from baseline 2 weeks after the last dose compared with placebo (21% vs. 5%, P < 0.001); 12% of patients treated with alefacept 10 mg IM reached this level of improvement (P = NS vs. placebo). Alefacept was well tolerated, with adverse events similar to that of placebo.Conclusions Treatment with alefacept 15 mg IM provided highly significant improvements in all measures of psoriasis disease activity compared with placebo. Pharmacodynamic data confirmed that alefacept is a selective biological agent that reduces memory‐effector T cells (CD4+CD45RO+ and CD8+CD45RO+), the source of the pathogenic mediators of psoriasis, while having relatively no effect on naive T‐cell populations.
Clinical response to alefacept: results of a phase 3 study of intravenous administration of alefacept in patients with chronic plaque psoriasis
Authors: Krueger GG 
Published: August 2003

ABSTRACTBackground There is a current lack of safe and effective psoriasis therapies that provide patients with lasting remissions after treatment is discontinued. Alefacept, a novel and selective biological agent, has demonstrated durable efficacy in patients with chronic plaque psoriasis, and its efficacy has been correlated with reductions in memory‐effector T cells.Objective To demonstrate the efficacy and safety of both one and two 12‐week courses of alefacept 7.5 mg given once weekly as an intravenous (IV) bolus injection in patients with chronic plaque psoriasis.Methods Multicentre (51 centres in the USA and Canada), randomized, double‐blind, parallel‐group study comparing once‐weekly alefacept 7.5 mg IV or placebo for two 12‐week treatment courses. Each course had a 12‐week follow‐up phase. Patients were eligible for enrolment if they were ≥16 years of age, had chronic plaque psoriasis for ≥12 months involving ≥10% body surface area, and had CD4+ T‐cell counts at or above the lower limit of normal.Results 553 patients received treatment in Course 1, and 449 were treated in Course 2. The cohorts were well balanced for demographic and baseline disease characteristics. During the treatment and follow‐up period of Course 1, 28% of patients treated with alefacept achieved ≥75% reduction in Psoriasis Area and Severity Index (PASI), compared with 8% of placebo‐treated patients (P < 0.001). Patients achieving ≥75% reduction in PASI following a single 12‐week course of alefacept maintained ≥50% reduction in PASI for a median of over 7 months. Among patients who received a second course of alefacept therapy, 71% achieved ≥50% reduction in PASI, and 40% achieved ≥75% reduction in PASI over two treatment courses. One or two 12‐week courses of alefacept were similarly well tolerated.Conclusions Treatment with alefacept 7.5 mg IV provided highly significant improvements in all measures of psoriasis disease activity compared with placebo. A second course of alefacept provided additional benefit.
ARC6 Is a J-Domain Plastid Division Protein and an Evolutionary Descendant of the Cyanobacterial Cell Division Protein Ftn2[W]
Authors: Vitha Stanislav , Froehlich John E. , Koksharova Olga , Pyke Kevin A. , van Erp Harrie , Osteryoung Katherine W. 
Published: August 2003

AbstractReplication of chloroplasts is essential for achieving and maintaining optimal plastid numbers in plant cells. The plastid division machinery contains components of both endosymbiotic and host cell origin, but little is known about the regulation and molecular mechanisms that govern the division process. The Arabidopsis mutant arc6 is defective in plastid division, and its leaf mesophyll cells contain only one or two grossly enlarged chloroplasts. We show here that arc6 chloroplasts also exhibit abnormal localization of the key plastid division proteins FtsZ1 and FtsZ2. Whereas in wild-type plants, the FtsZ proteins assemble into a ring at the plastid division site, chloroplasts in the arc6 mutant contain numerous short, disorganized FtsZ filament fragments. We identified the mutation in arc6 and show that the ARC6 gene encodes a chloroplast-targeted DnaJ-like protein localized to the plastid envelope membrane. An ARC6–green fluorescent protein fusion protein was localized to a ring at the center of the chloroplasts and rescued the chloroplast division defect in the arc6 mutant. The ARC6 gene product is related closely to Ftn2, a prokaryotic cell division protein unique to cyanobacteria. Based on the FtsZ filament morphology observed in the arc6 mutant and in plants that overexpress ARC6, we hypothesize that ARC6 functions in the assembly and/or stabilization of the plastid-dividing FtsZ ring. We also analyzed FtsZ localization patterns in transgenic plants in which plastid division was blocked by altered expression of the division site–determining factor AtMinD. Our results indicate that MinD and ARC6 act in opposite directions: ARC6 promotes and MinD inhibits FtsZ filament formation in the chloroplast.
The Arabidopsis Basic/Helix-Loop-Helix Transcription Factor Family[W]
Authors: Toledo-Ortiz Gabriela , Huq Enamul , Quail Peter H. 
Published: August 2003

AbstractThe basic/helix-loop-helix (bHLH) proteins are a superfamily of transcription factors that bind as dimers to specific DNA target sites and that have been well characterized in nonplant eukaryotes as important regulatory components in diverse biological processes. Based on evidence that the bHLH protein PIF3 is a direct phytochrome reaction partner in the photoreceptor's signaling network, we have undertaken a comprehensive computational analysis of the Arabidopsis genome sequence databases to define the scope and features of the bHLH family. Using a set of criteria derived from a previously defined consensus motif, we identified 147 bHLH protein–encoding genes, making this one of the largest transcription factor families in Arabidopsis. Phylogenetic analysis of the bHLH domain sequences permits classification of these genes into 21 subfamilies. The evolutionary and potential functional relationships implied by this analysis are supported by other criteria, including the chromosomal distribution of these genes relative to duplicated genome segments, the conservation of variant exon/intron structural patterns, and the predicted DNA binding activities within subfamilies. Considerable diversity in DNA binding site specificity among family members is predicted, and marked divergence in protein sequence outside of the conserved bHLH domain is observed. Together with the established propensity of bHLH factors to engage in varying degrees of homodimerization and heterodimerization, these observations suggest that the Arabidopsis bHLH proteins have the potential to participate in an extensive set of combinatorial interactions, endowing them with the capacity to be involved in the regulation of a multiplicity of transcriptional programs. We provide evidence from yeast two-hybrid and in vitro binding assays that two related phytochrome-interacting members in the Arabidopsis family, PIF3 and PIF4, can form both homodimers and heterodimers and that all three dimeric configurations can bind specifically to the G-box DNA sequence motif CACGTG. These data are consistent, in principle, with the operation of this combinatorial mechanism in Arabidopsis.
Crime That Pays: The Global Spread of the Russian Mafia
Authors: Granville Johanna 
Published: August 2003

Books reviewed in this article:Robert I. Friedman, Red Mafia: How the Russian Mob Has Invaded AmericaPaul Klebnikov, Godfather of the Kremlin: Boris Berezovsky and the Looting of RussiaJames O. Finckenauer and Elin J. Waring, Russian Mafia in America: Immigration, Culture, and CrimeChrystia Freeland, Sale of the Century: Russia's Wild Ride from Communism to CapitalismJeffrey Robinson, The Merger: The Conglomeration of International Organized Crime
The impact of cognitive styles on perceptual distributed multimedia quality
Authors: Ghinea Gheorghita , Chen Sherry Y. 
Published: August 2003

AbstractMultimedia technology has been widely used in web‐based instruction, but previous studies have indicated that individual differences, especially cognitive styles, have significant effects on users’ preferences with respect to presentation of multimedia content. However, such research has thus far neglected to examine the effect of cognitive styles on users’ subjective perceptions of multimedia quality. This study aims to examine the relationships among users’ cognitive styles, the multimedia Quality of Service (QoS) delivered by the underlying network, and Quality of Perception (QoP), which encompasses user levels of enjoyment and understanding of the informational content provided by multimedia material. Accordingly, 132 users took part in an experiment in which they were shown multimedia video clips presented with different values of two QoS parameters (frame rate and colour depth). Results show that, whilst the two QoS parameters do not impact user QoP, multimedia content and dynamism levels significantly influence the user understanding and enjoyment component of QoP.
Learning from web‐based instructional systems and cognitive style
Authors: Graff Martin 
Published: August 2003

AbstractTwo of the principal issues, which have been addressed in assessments of the benefits of web‐based instructional systems, are firstly, whether the segmentation of information provided by the web structure aids users in apprehending the interrelationships between the units of information featured in the web. Secondly, whether providing the user with an overview of the web system assists in facilitating his/her learning. It is suggested in the present study that these two issues may be more effectively understood by a consideration of an individual's cognitive style. Fifty participants were assigned to one of two web‐based instructional systems featuring information on the subject of psychological ethics. The information in one of the web systems was segmented to a greater degree than the information in the other. Half the participants using each web system were given an overview of the system and half were not. After a given time using the system, participants were tested on the information from the web. The findings suggest that cognitive style and segmentation had an effect on performance, although the provision of the overview had little effect. The results are discussed in terms of a consideration of cognitive style in the design of web‐based instructional systems.
Web‐based learning interaction and learning styles
Authors: Sabry Khaled , Baldwin Lynne 
Published: August 2003

AbstractThis paper reports a study exploring the learning styles and perceptions of a group of undergraduate and postgraduate learners in a university in the UK in relation to using the web for learning. In particular, we explore the sequential/global learning style dimension (which is concerned with the progress of understanding) in relation to three categories of web‐based interaction: learner‐tutor, learner‐learner, and learner‐information. An Index of Learning Styles is used as the tool to explore this dimension. The findings are presented with regard to the learning preferences of a group of learners towards these three categories of interaction. We conclude with a discussion of these findings in relation to Interactive Learning Systems (ILSs) design.