bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Re‐inventing’ China’s Industrial Relations at Enterprise‐Level: an Empirical Field‐Study in Four Major Cities
Authors: Ding Daniel Z. , Warner Malcolm
Published: April 2004

This article discusses the impact of China’s latest reforms on industrial relations at enterprise level in both state‐owned firms (SOEs) and foreign‐invested joint ventures (JVs) based on a sample of 24 industrial enterprises located in four cities. It concludes that the reforms of the early 1990s have ‘re‐invented’ the IR system and have significantly influenced recruitment and selection, wage and reward systems, and social security programmes.
Local Markets and the Polarization of Public‐Sector Schools in England and Wales
Authors: Gibson Alex , Asthana Sheena
Published: March 2004

Notwithstanding the recent change of government, UK educational policy continues to stress school performance tables, parental choice and competition – reflecting an acceptance by New Labour of Tory notions concerning the role that market mechanisms play in improving school performance. In view of the 1997 Education White Paper's insistence that the new government's goal was to ‘overcome the spiral of disadvantage … passed from one generation to the next’, this implies that the DfEE remains unimpressed by long‐standing arguments concerning the socially‐divisive consequences of market forces in education.

This paper seeks to add empirical weight to this debate. Arguing that recent analyses of aggregate levels of social stratification have masked polarization occurring at the local level, our analysis places schools in the context of the local markets within which they operate. This yields clear evidence that educational markets tend to exacerbate existing differences between schools in terms of both their performance and social status.
A Crowning Moment for Wiener Indices
Authors: Yang Bo‐Yin , Yeh Yeong‐Nan
Published: April 2004

The Wiener (Sum of All Distances) Index for three out of the four classes of hexagonal models or regular planar hex‐patterns used to model graphite and similar structures have been known for a few years. In this paper we find the Wiener Index for the Crown or Beehive hexagonal model.
The Effect of Meridional and Vertical Shear on the Interaction of Equatorial Baroclinic and Barotropic Rossby Waves
Authors: Biello Joseph A. , Majda Andrew J.
Published: April 2004

Simplified asymptotic equations describing the resonant nonlinear interaction of equatorial Rossby waves with barotropic Rossby waves with significant midlatitude projection in the presence of arbitrary vertically and meridionally sheared zonal mean winds are developed. The three mode equations presented here are an extension of the two mode equations derived by Majda and Biello [1] and arise in the physically relevant regime produced by seasonal heating when the vertical (baroclinic) mean shear has both symmetric and antisymmetric components; the dynamics of the equatorial baroclinic and both symmetric and antisymmetric barotropic waves is developed. The equations described here are novel in several respects and involve a linear dispersive wave system coupled through quadratic nonlinearities. Numerical simulations are used to explore the effect of antisymmetric baroclinic shear on the exchange of energy between equatorial baroclinic and barotropic waves; the main effect of moderate antisymmetric winds is to shift the barotropic waves meridionally. A purely meridionally antisymmetric mean shear yields highly asymmetric waves which often propagate across the equator. The two mode equations appropriate to Ref. [1] are shown to have analytic solitary wave solutions and some representative examples with their velocity fields are presented.
Estimating Farm Equipment Depreciation: Which Functional Form Is Best?
Authors: Wu Jing , Perry Gregory M.
Published: March 2004

Farm equipment depreciation has been the focus of research in economics and engineering for more than 60 years. Using data from 16 years of auction sales, depreciation functions were estimated for 17 types of equipment, including tractors, combines, swathers, planters, discs, and trucks. The Box—Cox function did the best job of explaining variability in these various sales data bases and in forecasting prices in an out‐of‐sample data set. Nevertheless, the much less complicated double square root and sum‐of‐year's digits functions performed nearly as well. Simplified double square root estimates are provided for practitioners interested in forecasting equipment depreciation.
How do age and tooth loss affect oral health impacts and quality of life? A study comparing two national samples
Authors: Steele James G. , Sanders Anne E. , Slade Gary D. , Allen Patrick Finbarr , Lahti Satu , Nuttall Nigel , Spencer A. John
Published: April 2004

Abstract  – Age and loss of teeth can be expected to have a complex relationship with oral health‐related quality of life. This study aimed to explain how age and tooth loss affect the impact of oral health on daily living using the short form, 14‐item Oral Health Impact Profile (OHIP‐14) on national population samples of dentate adults from the UK (1998 UK Adult Dental Health Survey) and Australia (1999 National Dental Telephone Interview Survey). After correcting for key covariables, increasing age was associated with better mean impact scores in both populations. Those aged 30–49 years in Australia showed the worst (highest) scores. In the UK, those aged under 30 showed the highest scores. In both countries, adults aged 70+ showed much better scores than the rest (P < 0.001). When corrected for age, the independent effect of tooth loss was that the worst scores were found where there were fewer than 17 natural teeth in the UK and fewer than 21 teeth in Australia. People with 25 or more teeth averaged much better scores than all other groups (P < 0.001), although there were differences in pattern between countries. When Australians were analysed by region of birth, the pattern of scores by tooth loss for British/Irish immigrants was strikingly similar to that for the UK sample. First‐generation immigrants from elsewhere showed much worse overall scores and a profoundly different pattern to the Australian‐ and British‐born groups. Age, number of teeth and cultural background are important variables influencing oral health‐related quality of life.
Ratio dependence in the functional response of insect parasitoids: evidence fromTrichogramma minutumforaging for eggs in small host patches
Authors: Mills N. J. , Lacan I.
Published: April 2004

Abstract. 1. Despite considerable recent debate on the suitability of ratio dependence as a more general form for the functional response in consumer–victim relationships, there have been few detailed studies to experimentally determine the response of insect parasitoids to host and parasitoid density at a local scale.

2. The experimental host,Ephestia kuehniella, was used to test for host dependence and ratio dependence in the functional response of the egg parasitoid,Trichogramma minutum, a species widely used in inundative biological control. The functional response was examined through four series of experiments in which either host density, parasitoid density, or the ratio of previously parasitised to healthy hosts was manipulated.

3. The response to host density was type I for both single and simultaneously foraging parasitoids, indicating a lack of host dependence in the functional response. The upper limit to the response was estimated as 39 hosts attacked in a 24‐h period, with an estimated per capita search rate of 1.32 for individual females and 0.37 for three simultaneously searching females.

4. The response to parasitoid density provided an interference constant of unity, indicating an equal sharing of hosts and thus ratio dependence in the functional response. Female parasitoids responded to the presence of conspecifically parasitised eggs with a significant increase in search rate (1.75), but with no change to the form or upper limit of the response.

5. It is suggested that ratio dependence may be more common among insect parasitoids than previously supposed, and that a type I functional response, or the absence of host dependence, may be an emergent property of phylogenetic constraint within the monophyletic grouping ofCales,Eretmocerus, andTrichogramma.
Recruitment of osteoclasts in the mandible of osteopetrotic (op/op) mice
Authors: Ida‐Yonemochi Hiroko , Ishibashi Osamu , Sakai Hideaki , Saku Takashi
Published: March 2004

Osteoclasts in osteopetrotic (op/op) mice are substantially reduced by the absence of functional activities of macrophage colony‐stimulating factor (M‐CSF). However, it is known that osteoclasts appear in op/op skeletal bones with aging, although the molecular mechanism for this is unknown. In order to investigate osteoclastic recruitment in the jaw bones of op/op mice, osteoclastic distribution was analysed for 2 yr after birth by histochemistry for tartrate‐resistant acid phosphatase activity and immunohistochemistry for cathepsin K. Osteoclasts in op/op mandibular bones decreased rapidly in number after birth and disappeared by 3 d, although there was no difference in the osteoclastic distribution between op/op and normal littermates at birth. At 2 wk, osteoclasts began to reappear around op/op tooth germs, where no apparent connective tissue layer intervened between tooth germs and bone trabeculae. They increased in number and were scattered over the mandible, reaching a maximum at 8 wk, when periodontal ligament‐like structures were recognizable around incisor germs. Osteoclasts then again decreased gradually, and after 62 wk few osteoclasts were seen in op/op mandibular bones, whose marrow space disappeared. These findings suggest that osteoclasts are recruited in an M‐CSF‐independent manner in op/op mandibles, especially in areas around tooth germs.
The relation of tobacco smoking to tooth loss among young adults
Authors: Ylöstalo Pekka , Sakki Tero , Laitinen Jaana , Järvelin Marjo‐Riitta , Knuuttila Matti
Published: March 2004

Earlier studies have associated smoking with a higher rate of dental caries, periodontal disease and tooth loss. The aim of this cross‐sectional study was to determine whether smoking is associated with tooth loss among young adults. The data consist of the 1966 birth cohort of Northern Finland, which is an unselected general population birth cohort (n = 12 058). The data were collected using a postal questionnaire in 1997–98 (n = 8690). Prevalence odds ratios and confidence intervals were estimated by applying a logistic regression model. It was found that smoking was associated with tooth loss in an exposure‐dependent manner. The odds for those who smoked 16 or more pack‐years were 5.30 (CI = 2.35–11.2) after adjustment for socio‐economic and behavioral factors. Differences in socio‐economic or health behavior are not likely to explain the findings since an exposure‐response pattern was seen even when data was stratified according to sex, education and health‐oriented lifestyle. A possible explanation for this association is a combination of treatment decisions and dental diseases, which are most likely associated with smoking in an exposure‐dependent manner.
Rank Order of Success Favors Longer Duration of Imidazole‐Based Therapy for Helicobacter pylori in Duodenal Ulcer Disease: A Randomized Pilot Study
Authors: Chaudhary Ashmit , Ahuja Vineet , Bal Chandrasekhar S. , Das Bimal , Pandey Ravinder Mohan , Sharma Mahesh Prakash
Published: April 2004

Background.  Studies on eradication therapy in developing countries have shown a success rate of 70–85%, which is suboptimal. Duration of therapy may be an important factor dictating eradication success in such regions.

Aim.  The study was undertaken to evaluate the effect of increasing the treatment period on eradication of Helicobacter pylori in duodenal ulcer disease.

Methods.  A randomized trial was carried out in which 64 consecutive H. pylori‐infected patients with duodenal ulcer disease were enrolled. The patients were randomized to one of the three trial arms. Therapy consisted of lansoprazole 30 mg twice a day (b.i.d.), amoxycillin 1 g b.i.d. and tinidazole 500 mg b.i.d. The treatment period was 1 week in group I, 2 weeks in group II and 3 weeks in group III. At inclusion, patients underwent endoscopy and the presence of H. pylori was documented by a positive urease test and C14 urea breath test. Four weeks after completion of eradication therapy, the patients were subjected to repeat endoscopy to assess ulcer healing and tests for H. pylori infection.

Results.  Sixty‐four patients (55 male and nine female; mean age 35.5 years) were enrolled in each group. The H. pylori eradication rate for group I (1 week of therapy) was 47.6%, that for group II (2 weeks of therapy) was 80%, and that for group III (3 weeks of therapy) was 91.3% (p = .003). The ulcer healing rates were 71.4, 80 and 95.6% in groups I, II and III, respectively (p = .09).

Conclusion.  The 3‐week regimen significantly improved the eradication rate as compared with the 1‐week regime. Increasing the duration of therapy significantly improved the chances of eradication of H. pylori in duodenal ulcer disease.
New Books on Darwinism Look at the Religious and Rhetorical Aspects of Evolutionary Theory
Authors: Anderson Owen
Published: April 2004

Darwin's Proof: The Triumph of Religion Over Science, Cornelius Hunter, Brazos Press 2003 (1‐58743‐056‐8), pp. 168, Hb $17.99

Doubts About Darwin: A History of Intelligent Design, Thomas Woodward, Baker Books 2003 (0‐8010‐6443‐0), pp. 303, Hb $19.99
The reconstituted human Chl12‐RFC complex functions as a second PCNA loader
Authors: Shiomi Yasushi , Shinozaki Ayako , Sugimoto Katsunori , Usukura Jiro , Obuse Chikashi , Tsurimoto Toshiki
Published: April 2004

The sister chromatid cohesion factor Chl12 shares amino acid sequence similarity with RFC1, the largest subunit of replication factor C (RFC), and forms a clamp loader complex in association with the RFC small subunits RFCs2‐5. It has been shown that the human Chl12‐RFC complex, reconstituted with a baculovirus expression system, specifically interacts with human proliferating cell nuclear antigen (PCNA). The purified Chl12‐RFC complex is structurally indistinguishable from RFC, as shown by electron microscopy, and it exhibits DNA‐stimulated ATPase activity that is further enhanced by PCNA, and by DNA binding activity on specific primer/template DNA structures. Furthermore, the complex loads PCNA onto a circular DNA substrate, and stimulates DNA polymerase δ DNA synthesis on a primed M13 single‐stranded template in the presence of purified replication proteins. However, it cannot substitute for RFC in promoting simian virus 40 DNA replicationin vitrowith crude fractions. These results demonstrate that the human Chl12‐RFC complex is a second PCNA loader and that its roles in replication are clearly distinguishable from those of RFC.
Reflective practice and clinical supervision: an interprofessional perspective
Authors: Clouder Lynn , Sellars Julie
Published: April 2004

Background.  In the United Kingdom, the drive to encourage reflective practice through clinical supervision, as a means of ensuring quality of provision in nursing and other health care professions, is now well‐embedded, not only in policy but also in practice. However, debate and critique of these concepts is limited.

Aim.  The aim of this paper is to draw on research, conducted with undergraduate occupational therapy students and qualified physiotherapists, in order to contribute to the debate about the functions of clinical supervision and reflective practice in nursing and other health care professions.

Discussion.  Upholding the notion that clinical supervision has the potential to constitute a form of surveillance, we counter the assumption that it is inevitably confessional in nature. A social constructionist perspective is used to illustrate how clinical supervision might involve a complex interplay of factors that dispel notions of predictability, control and rationality.

Conclusion.  Despite acknowledging tensions, we argue that clinical supervision is both necessary and beneficial. It can be advantageous to individual practitioners and professional groups in enhancing practice and accountability, and promoting professional development.
Registered Nurses’ work experiences: personal accounts integrated with professional identity
Authors: Fagerberg Ingegerd
Published: April 2004

Background.  The work context is important for the development of Registered Nurses’ skills and identity as professionals, but the work context and organization can also hinder their professional development.

Aim.  This paper reports a study whose purpose was to understand the meaning of Registered Nurses’ narratives of their work experience 5 years after graduation.

Research method.  Data were collected in 2001 from interviews with 16 Registered Nurses 5 years after graduation and analysed using a phenomenological hermeneutic method, influenced by the philosophy of Paul Ricoeur.

Results.  Analyses of the narratives resulted in three themes: ‘The meaning of caring and protection of patients’, ‘The meaning of work organization in nurses’ work’ and ‘The implied meaning of using one's individual attributes in one's professional role’. Since the number of nurses participating in the study is small, it is important to re‐contextualize the results when transferring them to other contexts.

Conclusions.  There is a complex interrelationship between the health care organization, individual attributes of nurses (including self‐esteem) and patient care. Provision of adequate resources and support for nurses’ professional and personal development is needed to ensure high quality patient care, and these are political issues.
The smacking controversy: what advice should we be giving parents?
Authors: Taylor Julie , Redman Susan
Published: April 2004

Background.  Even among countries that have ratified the United Nations Convention on the Rights of the Child there is much disagreement about corporal punishment of children. Last year the Scottish Executive proposed a new law banning the smacking of children under the age of three, becoming the tenth European nation to do so. The proposal, currently abandoned whilst ostensibly still under debate, has raised a wave of controversy in child protection circles. In the nearest neighbouring country, England, a similar proposal was robustly rejected.

Purpose of the paper.  Given an increasing family and community focus in nursing, the implications of the debate for the profession cannot be ignored. What should we be telling ‘ordinary’ families about smacking? Thus this paper presents a positional statement on the smacking controversy and outlines some pointers for practice.

Discussion.  While for many the legislation proposed does not go far enough, others decry it as a breach of parental rights and, thus, the issue has become hugely controversial. Media opinion and various opposing campaigns dominate both public and professional spheres. Rights, responsibilities, examples from other countries, culture and gender are all used as fodder in the debate. Extreme examples are cited by both sides and used as grist for what are at times tenuous arguments. As there is even a division within child protection arenas, practising professionals may struggle to find a way through the maze of seemingly contradictory findings from research, policy and opinion.

Conclusions.  A wide range of literature suggests that both public and professional opinion is divided on the use of smacking as a form of discipline of young children. Opinion is also divided on the ability of legislation to bring about change in social attitudes and behaviour. Health care professionals need to be in a position to recommend best practice and to do so consistently.
Evaluating system‐based strategies for managing conflict in collaborative concept mapping
Authors: Chiu C.‐H.
Published: April 2004

This study examined the influence of various conflict management mechanisms embedded into computer‐supported collaborative concept mapping systems on the behaviour and learning of elementary students. Four conflict management mechanisms were compared: an assign design, in which the mapping control was designated to a particular group member; a rotate design, in which the mapping control was rotated among the group members; a give design, in which the child with mapping control could relinquish control to another group member; and an open design, in which every group member simultaneously had mapping control. Ninety‐six fifth and sixth grade Taiwanese students participated in this study. They were arranged into assign, rotate, give, or open three‐member groups to generate collaboratively shared concept maps. Student interactions, attitudes, and achievement were analysed. The results suggest that each conflict management mechanism has a different effect on the elementary students.
In search of online pedagogical models: investigating a paradigm change in teaching through the School for All community
Authors: Young S. S.‐C.
Published: April 2004

Following a preliminary evaluation of the Web‐mediated School for All in 2002, this study further examines the online teacher role and explores the possible pedagogical models in this Web‐based informal lifelong learning context through a long‐term innovative e‐learning project over a 2‐year period. The author documents the educational rationale, reviews related literature on Web‐based instructional design, and presents longitudinal in‐depth study results based on empirical data collected from the four Web‐course contests held over 2 years from the perspective of outstanding online teachers. Significantly, three categories of six Web‐based pedagogical models induced from this research project are presented, and the rationale for how and why teachers would prefer to use certain teaching models is discussed. In addition, the characteristics of the outstanding online teachers and issues inherent in this alternative mode of a Web‐based informal educational setting are discussed. Finally, more research issues, questions, and possibilities for future research work are raised or identified for further study.
Cognitive, social, motivational and health aspects of students in laptop classrooms
Authors: Trimmel Michael , Bachmann Julia
Published: April 2004

Effects on cognitive performance, social atmosphere, communication, motivation and aspects of strain were investigated when laptops were integrated in classrooms. According to a quasi‐experimental design 27 laptop students were compared with 22 non‐laptop students from the same high school, aged 17–18 years. Results of tests and questionnaires showed that laptop students had better spatial abilities and computer skills, furthermore higher participation, learning interest, motivation and pressure to perform were found in laptop classrooms. However, laptop students experienced greater physical discomfort, particularly in their arms, but concerning creativity, social intelligence and mental stress no group differences occurred. Results indicate that laptops integrated in teaching can enhance learning and motivation in schools, at least after 1.7 years of introduction, but health risks must be considered.
Chaperone activity of cytosolic small heat shock proteins from wheat
Authors: Basha Eman , Lee Garrett J. , Demeler Borries , Vierling Elizabeth
Published: April 2004

Small Hsps (sHsps) and the structurally related eye lens α‐crystallins are ubiquitous stress proteins that exhibit ATP‐independent molecular chaperone activity. We studied the chaperone activity of dodecameric wheat TaHsp16.9C‐I, a class I cytosolic sHsp from plants and the only eukaryotic sHsp for which a high resolution structure is available, along with the related wheat protein TaHsp17.8C‐II, which represents the evolutionarily distinct class II plant cytosolic sHsps. Despite the available structural information on TaHsp16.9C‐I, there is minimal data on its chaperone activity, and likewise, data on activity of the class II proteins is very limited. We prepared purified, recombinant TaHsp16.9C‐I and TaHsp17.8C‐II and find that the class II protein comprises a smaller oligomer than the dodecameric TaHsp16.9C‐I, suggesting class II proteins have a distinct mode of oligomer assembly as compared to the class I proteins. Using malate dehydrogenase as a substrate, TaHsp16.9C‐I was shown to be a more effective chaperone than TaHsp17.8C‐II in preventing heat‐induced malate dehydrogenase aggregation. As observed by EM, morphology of sHsp/substrate complexes depended on the sHsp used and on the ratio of sHsp to substrate. Surprisingly, heat‐denaturing firefly luciferase did not interact significantly with TaHsp16.9C‐I, although it was fully protected by TaHsp17.8C‐II. In total the data indicate sHsps show substrate specificity and suggest that N‐terminal residues contribute to substrate interactions.
Thermodynamic analysis of the unfolding and stability of the dimeric DNA‐binding protein HU from the hyperthermophilic eubacterium Thermotoga maritima and its E34D mutant
Authors: Ruiz‐Sanz Javier , Filimonov Vladimir V. , Christodoulou Evangelos , Vorgias Constantinos E. , Mateo Pedro L.
Published: April 2004

We have studied the stability of the histone‐like, DNA‐binding protein HU from the hyperthermophilic eubacterium Thermotoga maritima and its E34D mutant by differential scanning microcalorimetry and CD under acidic conditions at various concentrations within the range of 2–225 µm of monomer. The thermal unfolding of both proteins is highly reversible and clearly follows a two‐state dissociation/unfolding model from the folded, dimeric state to the unfolded, monomeric one. The unfolding enthalpy is very low even when taking into account that the two disordered DNA‐binding arms probably do not contribute to the cooperative unfolding, whereas the quite small value for the unfolding heat capacity change (3.7 kJ·K−1·mol−1) stabilizes the protein within a broad temperature range, as shown by the stability curves (Gibbs energy functions vs. temperature), even though the Gibbs energy of unfolding is not very high either. The protein is stable at pH 4.00 and 3.75, but becomes considerably less so at pH 3.50 and below, to the point that a simple decrease in concentration will lead to unfolding of both the wild‐type and the mutant protein at pH 3.50 and low temperatures. This indicates that various acid residues lose their charges leaving uncompensated positively charged clusters. The wild‐type protein is more stable than its E34D mutant, particularly at pH 4.00 and 3.75 although less so at 3.50 (1.8, 1.6 and 0.6 kJ·mol−1 at 25 °C for ΔΔG at pH 4.00, 3.75 and 3.50, respectively), which seems to be related to the effect of a salt bridge between E34 and K13.
Well‐defined secondary structures
Authors: Sanford Adam R. , Yamato Kazuhiro , Yang Xiaowu , Yuan Lihua , Han Yaohua , Gong Bing
Published: April 2004

Molecules and assemblies of molecules with well‐defined secondary structures have been designed and characterized by controlling noncovalent interactions. By specifying intermolecular interactions, a class of information‐storing molecular duplexes have been successfully developed. These H‐bonded molecular duplexes demonstrate programmable, sequence‐specificity and predictable, tunable stabilities. Based on these highly specific molecular zippers (or glues), a systematic approach to designing self‐assembled structures is now feasible. Duplex‐directed formation of β‐sheets, block copolymers and templated organic reactions have been realized. By specifying intramolecular noncovalent interactions, a backbone‐rigidification strategy has been established, leading to unnatural molecular strands that adopt well‐defined, crescent or helical conformations. The generality of this backbone‐rigidification strategy has been demonstrated in three different classes of unnatural oligomers: oligoaramides, oligoureas and oligo(phenylene ethynylenes). Large nanosized cavities have been created based on the folding of these helical foldamers. Tuning the size of the nanocavities has been achieved without changing the underlying helical topology. These helical foldamers can serve as novel platforms for the systematic design of nanostructures.
Mutational analysis of a type II thioesterase associated with nonribosomal peptide synthesis
Authors: Linne Uwe , Schwarzer Dirk , Schroeder Gunnar N. , Marahiel Mohamed A.
Published: April 2004

Recent studies on type II thioesterases (TEIIs) involved in microbial secondary metabolism described a role for these enzymes in the removal of short acyl‐S‐ phosphopantetheine intermediates from misprimed holo‐(acyl carrier proteins) and holo‐(peptidyl carrier proteins) of polyketide synthases and nonribosomal peptide synthetases. Because of the absence of structural information on this class of enzymes, we performed a mutational analysis on a prototype TEII essential for efficient production of the lipopeptide antibiotic surfactin (TEIIsrf), which led to identification of catalytic and structural residues. On the basis of sequence alignment of 16 TEIIs, 10 single and one double mutant of highly conserved residues of TEIIsrf were constructed and biochemically investigated. We clearly identified a catalytic triad consisting of Ser86, Asp190 and His216, suggesting that TEIIsrf belongs to the α/β‐hydrolase superfamily. Exchange of these residues with residues with aliphatic side chains abolished enzyme activity, whereas replacement of the active‐site Ser86 with cysteine produced an enzyme with marginally reduced activity. In contrast, exchange of the second strictly conserved asparagine (Asp163) with Ala resulted in an active but unstable enzyme, excluding a role for this residue in catalysis and suggesting a structural function. The results define three catalytic and at least one structural residue in a nonribosomal peptide synthetase TEII.
APSGFLGMRamide is a unique tachykinin‐related peptide in crustaceans
Authors: Yasuda‐Kamatani Yoshimi , Yasuda Akikazu
Published: April 2004

We report here the identification of a tachykinin‐related peptide (TRP) in crustaceans. Direct MALDI‐TOF MS with brain slices of the crayfish Procambarus clarkii indicated the presence of a peptide having an MS number of around 934. Quadrupole orthogonal acceleration time‐of‐flight (Q‐TOF) MS/MS analysis implied the sequence to be APSGFLGMRamide, identical to that of CabTRP Ia, isolated previously from the crab Cancer borealis, and Pev‐tachykinin, from the shrimp Penaeus vannamei. The peptide has been shown to be myoactive in the cockroach hindgut, but the structure of its precursor protein had not been elucidated. A cDNA encoding crayfish preproTRP was cloned, revealing that the 225‐residue protein contains seven identical copies of the peptide APSGFLGMRamide. This is unique because TRPs identified in other invertebrates were known to exist in several related forms in each species. The conserved structure of TRP in crustaceans was confirmed by cloning preproTRP from the spiny lobster Panulirus interruptus. RT‐PCR and Northern blotting analyses suggested that the crayfish preproTRP mRNA is expressed throughout the nervous system, and in situ hybridization studies of the brain revealed that the transcript predominantly localizes to cell clusters 11 (dorsal lateral cells) and 9 (ventral lateral cells).
Activation of p21‐activated kinase 1 is required for lysophosphatidic acid‐induced focal adhesion kinase phosphorylation and cell motility in human melanoma A2058 cells
Authors: Jung In Duk , Lee Jangsoon , Lee Kyung Bok , Park Chang Gyo , Kim Yong Kee , Seo Dong Wan , Park Dongeun , Lee Hyang Woo , Han Jeung‐Whan , Lee Hoi Young
Published: April 2004

Lysophosphatidic acid (LPA), one of the naturally occurring phospholipids, stimulates cell motility through the activation of Rho family members, but the signaling mechanisms remain to be elucidated. In the present study, we investigated the roles of p21‐activated kinase 1 (PAK1) on LPA‐induced focal adhesion kinase (FAK) phosphorylation and cell motility. Treatment of human melanoma cells A2058 with LPA increased phosphorylation and activation of PAK1, which was blocked by treatment with pertussis toxin and by inhibition of phosphoinositide 3‐kinase (PI3K) with an inhibitor LY294002 or by overexpression of catalytically inactive mutant of PI3Kγ, indicating that LPA‐induced PAK1 activation was mediated via a Gi protein and the PI3Kγ signaling pathway. In addition, we demonstrated that Rac1/Cdc42 signals acted as upstream effector molecules of LPA‐induced PAK activation. However, Rho‐associated kinase, MAP kinase kinase 1/2 or phospholipase C might not be involved in LPA‐induced PAK1 activation or cell motility stimulation. Furthermore, PAK1 was necessary for FAK phosphorylation by LPA, which might cause cell migration, as transfection of the kinase deficient mutant of PAK1 or PAK auto‐inhibitory domain significantly abrogated LPA‐induced FAK phosphorylation. Taken together, these findings strongly indicated that PAK1 activation was necessary for LPA‐induced cell motility and FAK phosphorylation that might be mediated by sequential activation of Gi protein, PI3Kγ and Rac1/Cdc42.
A novel R‐stereoselective amidase from Pseudomonas sp. MCI3434 acting on piperazine‐2‐tert‐butylcarboxamide
Authors: Komeda Hidenobu , Harada Hiroyuki , Washika Shingo , Sakamoto Takeshi , Ueda Makoto , Asano Yasuhisa
Published: April 2004

A novel amidase acting on (R,S)‐piperazine‐2‐tert‐butylcarboxamide was purified from Pseudomonas sp. MCI3434 and characterized. The enzyme acted R‐stereoselectively on (R,S)‐piperazine‐2‐tert‐butylcarboxamide to yield (R)‐piperazine‐2‐carboxylic acid, and was tentatively named R‐amidase. The N‐terminal amino acid sequence of the enzyme showed high sequence identity with that deduced from a gene named PA3598 encoding a hypothetical hydrolase in Pseudomonas aeruginosa PAO1. The gene encoding R‐amidase was cloned from the genomic DNA of Pseudomonas sp. MCI3434 and sequenced. Analysis of 1332 bp of the genomic DNA revealed the presence of one open reading frame (ramA) which encodes the R‐amidase. This enzyme, RamA, is composed of 274 amino acid residues (molecular mass, 30 128 Da), and the deduced amino acid sequence exhibits homology to a carbon–nitrogen hydrolase protein (PP3846) from Pseudomonas putida strain KT2440 (72.6% identity) and PA3598 protein from P. aeruginosa strain PAO1 (65.6% identity) and may be classified into a new subfamily in the carbon–nitrogen hydrolase family consisting of aliphatic amidase, β‐ureidopropionase, carbamylase, nitrilase, and so on. The amount of R‐amidase in the supernatant of the sonicated cell‐free extract of an Escherichia coli transformant overexpressing the ramA gene was about 30 000 times higher than that of Pseudomonas sp. MCI3434. The intact cells of the E. coli transformant could be used for the R‐stereoselective hydrolysis of racemic piperazine‐2‐tert‐butylcarboxamide. The recombinant enzyme was purified to electrophoretic homogeneity from cell‐free extract of the E. coli transformant overexpressing the ramA gene. On gel‐filtration chromatography, the enzyme appeared to be a monomer. It had maximal activity at 45 °C and pH 8.0, and was completely inactivated in the presence of p‐chloromercuribenzoate, N‐ethylmaleimide, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+, Hg2+ or Pb2+. RamA had hydrolyzing activity toward the carboxamide compounds, in which amino or imino group is connected to β‐ or γ‐carbon, such as β‐alaninamide, (R)‐piperazine‐2‐carboxamide (R)‐piperidine‐3‐carboxamide, d‐glutaminamide and (R)‐piperazine‐2‐tert‐butylcarboxamide. The enzyme, however, did not act on the other amide substrates for the aliphatic amidase despite its sequence similarity to RamA.
Indirect evidence that frugivorous birds track fluctuating fruit resources among rainforest patches in the Northern Territory, Australia
Authors: Price Owen Francis
Published: April 2004

Abstract  Rainforests are naturally fragmented in the Northern Territory of Australia. A census of fruit and frugivorous bird abundance was taken monthly in 10 rainforest patches for 1 year and quarterly for a second year to investigate spatial and temporal patterns among the patches. Fruit abundance showed a marked annual cycle, with a peak around December in the wet season. Four of six bird species showed a significant seasonal fluctuation in abundance, and for three of them, these patterns were different among rainforest types. Three species also showed a significant tendency to be most abundant in the rainforest type with the most fruit in any month. We interpret these results as evidence that birds track fruit resources among rainforest patches of different types. The abundance of two of the species (figbird and pied imperial‐pigeon) was highly variable and did not reveal significantly different temporal trends among rainforest types. These species are probably even more mobile than the other species, although the data in the present study cannot be used to test this theory. The conservation of frugivorous birds and of the plants whose seeds they disperse will require the protection of networks of rainforest patches.
Response of vegetation and vertebrate fauna to 23 years of fire exclusion in a tropical Eucalyptus open forest, Northern Territory, Australia
Authors: Woinarski J. C. Z. , Risler J. , Kean L.
Published: April 2004

Abstract  This opportunistic study compares the vegetation, fuel loads and vertebrate fauna of part of a 120‐ha block of tropical open forest protected from fire for 23 years, and an adjacent block burnt annually over this period. Total fuel loads did not differ significantly between the unburnt and annually burnt sites, but their composition was markedly different, with far less grassy fuel, but far more litter fuel, in the unburnt block. There were major differences between treatments in the composition of trees and shrubs, manifest particularly in the number of stems. There was no overall difference in plant species richness between the two treatments, but richness of woody species was far higher in the unburnt treatment, and of annual and perennial grasses, and perennial herbs in the annually burnt treatment. Change in plant species composition from annually burnt to unburnt treatment was directional, in that there was a far higher representation of rainforest‐associated species (with the percentage of woody stems attributable to ‘rainforest’ species increasing from 24% of all species in the annually burnt treatment to 43% in the unburnt treatment, that of basal area from 9% to 30%, that of species richness from 8% to 17%, and that of cover from 12 to 47%). The vertebrate species composition varied significantly between treatments, but there was relatively little difference in species richness (other than for a slightly richer reptile fauna in the unburnt treatment). Again, there was a tendency for species that were more common in the unburnt treatment to be rainforest‐associated species. The results from this study suggest that there is a sizeable and distinct set of species that are associated with relatively long‐unburnt environments, and hence that are strongly disadvantaged under contemporary fire regimes. We suggest that such species need to be better accommodated by fire management through strategic reductions in the frequency of burning.
Breeding system, pollination and demography in the rare granite endemic shrub Verticordia staminosa ssp. staminosa in south‐west Western Australia
Authors: Yates Colin J. , Ladd Philip G.
Published: April 2004

Abstract  Verticordia staminosa C. Gardner & A. S. George staminosa (Myrtaceae) is a rare granite endemic shrub that grows in discrete subpopulations on one isolated rock outcrop in a remnant of native vegetation in the Western Australian wheat belt. Key considerations in assessing the risk of extinction for rare plant species in fragmented landscapes are the reproductive dependence on a pollinator, breeding system, importance of seeds in demography, and regeneration niche. The present study determined the extent to which these factors constrain population growth in V. staminosa ssp. staminosa. Measurements across nine subpopulations on the breeding system, pollinator activity, rates of flowering, pollination and seed production, seedling demography, mature plant mortality and size‐class structure were undertaken over three consecutive years. The study species has a mixed mating system with similar rates of pollen tube development and fertilization observed in self‐, cross‐ and open‐pollinated flowers. Floral morphology, orientation and the concentration and volume of nectar produced suggest some degree of specialization associated with pollination by birds, which were occasionally seen visiting flowers. However, feral honey bees were the most commonly observed flower visitor and they seem to have replaced honeyeaters as the primary pollinator. Honey‐bee abundance increased with subpopulation size. However, rates of pollination and the subsequent proportion of flowers that produced viable seeds were independent of subpopulation size. Germination and seedling emergence occurred each winter but were greatest in the wettest winter. Recruitment was heavily biased towards individuals growing in or over cracks/fissures in the rock. Over the 3‐year study, recruitment exceeded mortality. A relatively unspecialized flower and mixed mating system have buffered the taxon against the effects of pollinator disruption. Seed production does not constrain population growth. The environmental variables of climate and suitable establishment crevices appear to be the major constraints to population growth.
Below‐ground biomass and productivity of a grazed site and a neighbouring ungrazed exclosure in a grassland in central Argentina
Authors: Pucheta Eduardo , Bonamici Ivano , Cabido Marcelo , Díaz Sandra
Published: April 2004

Abstract  We estimated the below‐ground net plant productivity (BNPP) of different biomass components in an intensively and continuously 45‐ha grazed site and in a neighbouring exclosure ungrazed for 16 years for a natural mountain grassland in central Argentina. We measured approximately twice as much dead below‐ground biomass in the grazed site as in the ungrazed site, with a strong concentration of total below‐ground biomass towards the upper 10 cm of the soil layer in both sites. The main contribution to total live biomass was accounted for by very fine (<0.5 mm) and fine roots (0.5–1.0 mm) both at the grazed (79%) and at the ungrazed (81%) sites. We measured more dead biomass for almost all root components, more live biomass of rhizomes, tap roots and bulbs, and less live biomass of thicker roots (>1 mm) in the grazed site. The seasonal variation of total live below‐ground biomass mainly reflected climate, with the growing season being limited to the warmer and wetter portion of the year, but such variation was higher in the grazed site. Using different methods of estimation of BNPP, we estimated maximum values of 1241 and 723 g m−2 year−1 for the grazed and ungrazed sites, respectively. We estimated that very fine root productivity was almost twice as high at the grazed site as at the ungrazed one, despite the fact that both sites had similar total live biomass, and root turnover rate was twofold at the grazed site.
Fire frequency and time‐since‐fire effects on the open‐forest and woodland flora of Girraween National Park, south‐east Queensland, Australia
Authors: Watson Penny , Wardell‐Johnson Grant
Published: April 2004

Abstract  The effects of recent fire frequency and time‐since‐fire on plant community composition and species abundance in open‐forest and woodland vegetation in Girraween National Park, south‐east Queensland, Australia, were examined. Cover‐abundance data were collected for shrub and vine species in at least 10 400‐m2 plots in each of four study areas. Study areas were within one community type and had burnt most recently either 4 or 9 years previously. Variations in fire frequency allowed us to compare areas that had burnt at least three times in the previous 25 years with less frequently burnt areas, and also woodlands that had experienced a 28‐year interfire interval with more frequently burnt areas. Although species richness did not differ significantly with either time‐since‐fire or fire frequency, both these factors affected community composition, fire frequency being the more powerful. Moisture availability also influenced floristics. Of the 67 species found in five or more plots, six were significantly associated with time‐since‐fire, whereas 11 showed a significant difference between more and less frequently burnt plots in each of the two fire‐frequency variables. Most species, however, did not vary in cover‐abundance with the fire regime parameters examined. Even those species that showed a marked drop in cover‐abundance when exposed to a particular fire regime generally maintained some presence in the community. Five species with the capacity to resprout after fire were considered potentially at risk of local extinction under regimes of frequent fire, whereas two species were relatively uncommon in long‐unburnt areas. Variable fire regimes, which include interfire intervals of at least 15 years, could be necessary for the continuity of all species in the community.
Discourses in Norwegian Climate Policy: National Action or Thinking Globally?
Authors: Hovden Eivind , Lindseth Gard
Published: March 2004

Norway is often recognised as a pioneer country in environmental politics. Norwegian climate policy has changed considerably during the 1990s. It has evolved from a situation in 1989 where there was a broad consensus round the notion that a national target for stabilisation of CO2 emissions was the principal instrument for climate change abatement, to a situation at the turn of the century where Norway emerged as one of the most committed supporters of flexible mechanisms, the so-called ‘Kyoto mechanisms’. We identify two main discourses in the Norwegian politics of climate change, and label them ‘national action’ and ‘thinking globally’. This paper gives insight into the core elements of these two discourses and how they act as basic knowledge systems when actors put forward standpoints on the climate change issue.
About the Cover
Authors: Farnsworth David
Published: March 2004

The cover's statistics and beading are discussed.
Of Poohsticks and p‐Values: Hypothesis Testing in the Hundred Acre Wood
Authors: Nordmoe Eric D.
Published: March 2004

A walk through Milne's Enchanted Forest leads to an unexpected encounter with hypothesis testing.