bluuebunny/crossref_metadata_2025 huggingface dataset:
On the regimes of charge reversal
Authors: Jiménez-Ángeles Felipe , Lozada-Cassou Marcelo
Published: May 2008

Charge reversal of the planar electrical double layer is studied by means of a well known integral equation theory. By a numerical analysis, a diagram is constructed with the onset points of charge reversal in the space of the fundamental variables of the system. Within this diagram, two regimes of charge reversal are identified, which are referred to as oscillatory and nonoscillatory. We found that these two regimes can be distinguished through a simple formula. Furthermore, a symmetry between electrostatic and size correlations in charge reversal is exhibited. Agreement of our results with other theories and molecular simulations data is discussed.
A tentative model for estimating the compressibility of multiphased mixed crystals
Authors: Katsika-Tsigourakou Vassiliki , Vassilikou-Dova Aglaia
Published: April 2008

The growth of multiphased binary and ternary mixed crystals by the melt method using the miscible alkali halides, viz., NaBr and KCl, along with the experimental determination of their compressibility, have been recently reported. These materials are particularly useful for the construction of laser optical windows. Here, we suggest a theoretical model that enables the estimation of the compressibility of the multiphased mixed crystals in terms of the elastic data of the end members alone. The calculated values are in reasonable agreement with the experimental ones. The model makes use of an early suggestion that interconnects the Gibbs energy for the formation and migration of defects in solids, with bulk properties, and has been found of value in a large variety of solids.
Comment on “Dirac equation in the background of the Nutku helicoid metric” [J. Math. Phys. 48, 092301 (2007)]
Authors: Birkandan T. , Hortaçsu M.
Published: May 2008

The Dirac equation written on the boundary of the Nutku helicoid space consists of a system of ordinary differential equations. We tried to analyze this system and we found that it has a higher singularity than those of the Heun equations which give the solutions of the Dirac equation in the bulk. We also lose an independent integral of motion on the boundary. This facts explain why we could not find the solution of the system on the boundary in terms of known functions. We make the stability analysis of the helicoid and catenoid cases and end up with an Appendix which gives a new example wherein one encounters a form of the Heun equation.
Competitive growth mechanisms of aluminum nitride thin films deposited by off-normal reactive magnetron sputtering
Authors: Deniz D. , Karabacak T. , Harper J. M. E.
Published: April 2008

We have recently shown that AlN (0002) (c axis) is tilted abruptly toward the deposition direction as N2 concentration is increased in N2/Ar sputtering gas mixtures. Here, we present a Monte Carlo simulation model to describe the phenomenon of sudden c-axis AlN tilt. The model is based on the assumption that AlN islands with their c axis parallel to substrate normal and AlN islands with tilted c axis coexist at the initial stages of the growth and they can provide the adatoms with different surface mobilities. It is believed that the adatom mobilities are quenched when N2 concentration reaches a certain amount in the reactive sputtering of AlN. Our model further assumes that adatom mobility differences on different islands result in a growth rate difference of the islands. At the initial stages of the growth, AlN islands with tilted c axis grow taller due to the lower adatom mobility on these islands. As they grow taller, they win the competition and stop the further growth of AlN islands with their c axis parallel to substrate normal due to shadowing effect. Monte Carlo simulations revealed that the shadowing effect combined with different adatom mobilities promotes the sudden c-axis tilt in AlN thin films.
Engineering the randomness for enhanced absorption in solar cells
Authors: Fahr Stephan , Rockstuhl Carsten , Lederer Falk
Published: May 2008

Photon management by means of random textured surfaces is known to be a promising route to increase the light absorption in a solar cell. To date this randomness was only a posteriori assessed and related to the absorption. Here, we will outline a meaningful strategy for a priori and purposely tailoring the randomness. By defining appropriate angular scattering functions and optimizing the surface profiles, it is shown that the number of absorbed photons can be enhanced by 55% compared to flat-surface solar cells.
Application of 3C-SiC quantum dots for living cell imaging
Authors: Botsoa J. , Lysenko V. , Géloën A. , Marty O. , Bluet J. M. , Guillot G.
Published: May 2008

Highly luminescent, stable, and biocompatible 3C-SiC quantum dots (QDs) with no protective shells have been applied for fluorescence imaging of biological living cells. Structural and luminescent properties of the 3C-SiC QDs are described. Marking of the living cells with such QDs highlights the penetration, accumulation, and heterogeneous distribution of the QDs inside the intracellular space.
Optical gain in InGaN∕InGaAlN quantum well structures with zero internal field
Authors: Park Seoung-Hwan , Ahn Doyeol , Kim Jong-Wook
Published: May 2008

Electronic and optical properties of InGaN∕InAlGaN quantum well with zero internal field were investigated by using the non-Markovian gain model with many-body effects. The In composition x in the well to give zero internal field is shown to increase with the In composition y in the barrier. The InGaN∕AlGaInN system has much larger optical gain than the conventional InGaN∕GaN system because the optical matrix element is largely enhanced due to disappearance of the internal field. The peak gain is shown to decrease with increasing In composition for both systems. The decrease in the optical gain for the InGaN∕AlGaInN system is mainly due to the reduction in quasi-Fermi-level separation while that for the InGaN∕GaN system is due to the reduction in the matrix element.
Pygopus activates Wingless target gene transcription through the mediator complex subunits Med12 and Med13
Authors: Carrera Inés , Janody Florence , Leeds Nina , Duveau Fabien , Treisman Jessica E.
Published: May 2008

Wnt target gene transcription is mediated by nuclear translocation of stabilized β-catenin, which binds to TCF and recruits Pygopus, a cofactor with an unknown mechanism of action. The mediator complex is essential for the transcription of RNA polymerase II-dependent genes; it associates with an accessory subcomplex consisting of the Med12, Med13, Cdk8, and Cyclin C subunits. We show here that the Med12 and Med13 subunits of the
Drosophila
mediator complex, encoded by
kohtalo
and
skuld
, are essential for the transcription of Wingless target genes.
kohtalo
and
skuld
act downstream of β-catenin stabilization both
in vivo
and in cell culture. They are required for transcriptional activation by the N-terminal domain of Pygopus, and their physical interaction with Pygopus depends on this domain. We propose that Pygopus promotes Wnt target gene transcription by recruiting the mediator complex through interactions with Med12 and Med13.
Revealing the moonlighting role of NADP in the structure of a flavin-containing monooxygenase
Authors: Alfieri Andrea , Malito Enrico , Orru Roberto , Fraaije Marco W. , Mattevi Andrea
Published: April 2008

Flavin-containing monooxygenases (FMOs) are, after cytochromes P450, the most important monooxygenase system in humans and are involved in xenobiotics metabolism and variability in drug response. The x-ray structure of a soluble prokaryotic FMO from
Methylophaga
sp. strain SK1 has been solved at 2.6-Å resolution and is now the protein of known structure with the highest sequence similarity to human FMOs. The structure possesses a two-domain architecture, with both FAD and NADP
+
well defined by the electron density maps. Biochemical analysis shows that the prokaryotic enzyme shares many functional properties with mammalian FMOs, including substrate specificity and the ability to stabilize the hydroperoxyflavin intermediate that is crucial in substrate oxygenation. On the basis of their location in the structure, the nicotinamide ring and the adjacent ribose of NADP
+
turn out to be an integral part of the catalytic site being actively engaged in the stabilization of the oxygenating intermediate. This feature suggests that NADP(H) has a moonlighting role, in that it adopts two binding modes that allow it to function in both flavin reduction and oxygen reactivity modulation, respectively. We hypothesize that a relative domain rotation is needed to bring NADP(H) to these distinct positions inside the active site. Localization of mutations in human FMO3 that are known to cause trimethylaminuria (fish-odor syndrome) in the elucidated FMO structure provides a structural explanation for their biological effects.
Mutations in topoisomerase I as a self-resistance mechanism coevolved with the production of the anticancer alkaloid camptothecin in plants
Authors: Sirikantaramas Supaart , Yamazaki Mami , Saito Kazuki
Published: April 2008

Plants produce a variety of toxic compounds, which are often used as anticancer drugs. The self-resistance mechanism to these toxic metabolites in the producing plants, however, remains unclear. The plant-derived anticancer alkaloid camptothecin (CPT) induces cell death by targeting DNA topoisomerase I (Top1), the enzyme that catalyzes changes in DNA topology. We found that CPT-producing plants, including
Camptotheca acuminata
,
Ophiorrhiza pumila
, and
Ophiorrhiza liukiuensis
, have Top1s with point mutations that confer resistance to CPT, suggesting the effect of an endogenous toxic metabolite on the evolution of the target cellular component. Three amino acid substitutions that contribute to CPT resistance were identified: Asn421Lys, Leu530Ile, and Asn722Ser (numbered according to human Top1). The substitution at position 722 is identical to that found in CPT-resistant human cancer cells. The other mutations have not been found to date in CPT-resistant human cancer cells; this predicts the possibility of occurrence of these mutations in CPT-resistant human cancer patients in the future. Furthermore, comparative analysis of Top1s of CPT-producing and nonproducing plants suggested that the former were partially primed for CPT resistance before CPT biosynthesis evolved. Our results demonstrate the molecular mechanism of self-resistance to endogenously produced toxic compounds and the possibility of adaptive coevolution between the CPT production system and its target Top1 in the producing plants.
Pre‐pregnancy body mass index and weight gain during pregnancy in relation to preterm delivery subtypes
Authors: RUDRA CAROLE B. , FREDERICK IHUNNAYA O. , WILLIAMS MICHELLE A.
Published: April 2008

Background. Associations between preterm delivery (PTD) and pre‐pregnancy body mass index (BMI) and pregnancy weight gain may differ across outcome subtypes. Methods. The authors analyzed data from 2,468 cohort participants in western Washington State, USA (1996–2005) and examined pre‐pregnancy BMI and weight gain rate from pre‐pregnancy to 18–22 weeks’ gestation in relation to spontaneous PTD after preterm labor, spontaneous PTD after preterm premature rupture of membranes (PPROM), and indicated PTD. Results. Each 5kg/m2 BMI increase was associated with indicated PTD (adjusted odds ratio [OR] 1.71, 95% confidence interval [CI] 1.40–2.06). The association weakened somewhat after adjustment for hypertension and diabetes before and/or during pregnancy (5kg/m2 adjusted OR, 1.40; 95% CI, 1.12–1.75). Associations with spontaneous PTD and PPROM were weaker (5kg/m2 adjusted ORs, 0.90 and 1.14, respectively). Weight gain was associated with indicated delivery among women with normal BMI (0.1kg/week adjusted OR, 1.22; 95% CI, 1.02–1.45) but not among overweight or obese women (adjusted OR, 1.02; 95% CI, 0.87–1.20). Weight gain was inversely associated with spontaneous PTD (0.1kg/week adjusted OR, 0.87; 95% CI, 0.77–0.99) and not strongly associated with PPROM (adjusted OR, 1.03; 95% CI, 0.90–1.17). Conclusions. Pre‐pregnancy overweight increases indicated PTD risk independently of hypertension and diabetes. High early pregnancy weight gain increases indicated PTD risk in women with a normal BMI.
Establishment of a national Danish hysterectomy database: Preliminary report on the first 13,425 hysterectomies
Authors: HANSEN CHARLOTTE T. , MØLLER CHARLOTTE , DAUGBJERG SIGNE , UTZON JAN , KEHLET HENRIK , OTTESEN BENT ,   THE STEERING COMMITTEE OF THE DANISH HYSTERECTOMY DATABASE
Published: April 2008

Objective. To describe the concept and early results from the Danish Hysterectomy Database (DHD). Design. Nationwide prospective cohort. Setting. Denmark. Population. All women who had undergone an elective hysterectomy for benign indication carried out in 2004–2006. Methods. Structured data are registered prospectively by the surgeons involved in the treatment. Data is reported using the Danish National Patient Registry (LPR) and feedback is provided as clinical indicators with well‐defined goals. The DHD concept includes annual plenary meetings, elaboration of national clinical guidelines and parallel causal studies. Main outcome measures. Completeness, data validation and department‐identifiable clinical indicators (surgical volume, method of hysterectomy, use of antibiotic and thromboembolic prophylaxis, postoperative hospitalization and bleeding complications, surgical infections, reoperations, readmissions and death within 30 days postoperatively). Results. A total of 13,425 hysterectomies were performed in Denmark from 2004 to 2006. In 2005, all gynecological departments in Denmark (n = 31) were included in the database collaboration and the national response rate was 99%. Data validity was good in general (82–100% agreement and κ = 0.40–1.00) and data completeness was high (92–100% in 2006). From 2004 to 2006, two clinical guidelines were implemented, the postoperative hospitalization was stable at median 2 days, the rate of postoperative surgical infections was reduced from 4 to 2%, the rate of bleeding complications from 8 to 6%, the reoperation rate from 5 to 4%, and the readmission rate from 7 to 5%. Conclusions. Clinical performance indicators, audit meetings and nationwide collaboration are useful in monitoring and improving outcome after hysterectomy on a national level. In addition, the DHD offers scope for causal studies about perioperative management.
Development and validation of a nomogram to predict the risk of cesarean delivery in macrosomia
Authors: MAZOUNI CHAFIKA , ROUZIER ROMAN , COLLETTE EMMANUELLE , MENARD JEAN‐PIERRE , MAGNIN GEORGES , GAMERRE MARC , DETER RUSSELL
Published: April 2008

Objective. To develop and validate a nomogram that predicts individual probability of cesarean delivery in cases of macrosomia (>4,000 g). Methods. The nomogram was built based on the data from 246 patients who delivered macrosomic infants at Conception Hospital (Marseille, France), and was validated on an external population of 206 patients. Logistic regression was used to construct a model to predict the probability of cesarean section. The calculations were based on actual birth weight. Main outcome measures. The accuracy of the model was evaluated by area under the receiver operator curve. Results. In the multivariate analysis performed on the training set, maternal age (p = 0.002), parity (p = 0.003), and maternal height <1.65 m (p = 0.01) were found to be significantly associated with the occurrence of cesarean delivery and included in the nomogram. The final variables included in the nomogram were: age (p = 0.01), maternal height (p = 0.02), parity (p <0.001), and previous cesarean section (p = 0.009). Area under the ROCs was 0.80 and 0.78 in the training set before and after bootstrapping, respectively, and 0.88 in the validation set. The calibration of the nomogram was good. Conclusion. We have developed a nomogram based on actual birth weight that accurately predicts the risk of cesarean delivery in cases of macrosomia. This tool might be useful for decision‐making.
Introduction: Italy's foreign policy and the Mediterranean
Authors: Carbone Maurizio
Published: April 2008

Following the end of the Cold War, Italy took on greater responsibilities in dealing with the increased challenges to international security, especially in its neighbourhood. The aim of this special issue of the journal Modern Italy is to understand to what extent Italy has been successful in developing a third circle in its foreign policy beyond the two traditional lodestars, Atlanticism and Europeanism; or whether Italy's competence in the Mediterranean has been strategically used to improve its relationship with the United States or its position within the European Union.
Prion protein attenuates excitotoxicity by inhibiting NMDA receptors
Authors: Khosravani Houman , Zhang Yunfeng , Tsutsui Shigeki , Hameed Shahid , Altier Christophe , Hamid Jawed , Chen Lina , Villemaire Michelle , Ali Zenobia , Jirik Frank R. , Zamponi Gerald W.
Published: April 2008

It is well established that misfolded forms of cellular prion protein (PrP [PrPC]) are crucial in the genesis and progression of transmissible spongiform encephalitis, whereas the function of native PrPC remains incompletely understood. To determine the physiological role of PrPC, we examine the neurophysiological properties of hippocampal neurons isolated from PrP-null mice. We show that PrP-null mouse neurons exhibit enhanced and drastically prolonged N-methyl-d-aspartate (NMDA)–evoked currents as a result of a functional upregulation of NMDA receptors (NMDARs) containing NR2D subunits. These effects are phenocopied by RNA interference and are rescued upon the overexpression of exogenous PrPC. The enhanced NMDAR activity results in an increase in neuronal excitability as well as enhanced glutamate excitotoxicity both in vitro and in vivo. Thus, native PrPC mediates an important neuroprotective role by virtue of its ability to inhibit NR2D subunits.
FIP200, a ULK-interacting protein, is required for autophagosome formation in mammalian cells
Authors: Hara Taichi , Takamura Akito , Kishi Chieko , Iemura Shun-ichiro , Natsume Tohru , Guan Jun-Lin , Mizushima Noboru
Published: April 2008

Autophagy is a membrane-mediated intracellular degradation system. The serine/threonine kinase Atg1 plays an essential role in autophagosome formation. However, the role of the mammalian Atg1 homologues UNC-51–like kinase (ULK) 1 and 2 are not yet well understood. We found that murine ULK1 and 2 localized to autophagic isolation membrane under starvation conditions. Kinase-dead alleles of ULK1 and 2 exerted a dominant-negative effect on autophagosome formation, suggesting that ULK kinase activity is important for autophagy. We next screened for ULK binding proteins and identified the focal adhesion kinase family interacting protein of 200 kD (FIP200), which regulates diverse cellular functions such as cell size, proliferation, and migration. We found that FIP200 was redistributed from the cytoplasm to the isolation membrane under starvation conditions. In FIP200-deficient cells, autophagy induction by various treatments was abolished, and both stability and phosphorylation of ULK1 were impaired. These results suggest that FIP200 is a novel mammalian autophagy factor that functions together with ULKs.
PEPITO: improved discontinuous B-cell epitope prediction using multiple distance thresholds and half sphere exposure
Authors: Sweredoski Michael J. , Baldi Pierre
Published: April 2008

Motivation: Accurate prediction of B-cell epitopes is an important goal of computational immunology. Up to 90% of B-cell epitopes are discontinuous in nature, yet most predictors focus on linear epitopes. Even when the tertiary structure of the antigen is available, the accurate prediction of B-cell epitopes remains challenging.

Results: Our predictor, PEPITO, uses a combination of amino-acid propensity scores and half sphere exposure values at multiple distances to achieve state-of-the-art performance. PEPITO achieves an area under the curve (AUC) of 75.4 on the Discotope dataset. Additionally, we benchmark PEPITO as well as the Discotope predictor on the more recent Epitome dataset, achieving AUCs of 68.3 and 66.0, respectively.

Availability: PEPITO is available as part of the SCRATCH suite of protein structure predictors via www.igb.uci.edu.

Contact:  pfbaldi@ics.uci.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Retrospective stock assessment of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank between 1977 and 2006
Authors: Grandcourt E. M. , Hecht T. , Booth A. J. , Robinson J.
Published: April 2008

Grandcourt, E. M., Hecht, T., Booth, A. J., and Robinson, J. 2008. Retrospective stock assessment of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank between 1977 and 2006. – ICES Journal of Marine Science, 65: 889–898. The stock status of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank was determined between 1977 and 2006 using models of yield-per-recruit (YPR) and spawner-biomass-per-recruit (SBR). Demographic parameters were derived from size frequency and size-at-age data from validated annuli in sagittal otoliths. The long lifespan (tmax = 28 years), slow growth rate (k = 0.14), empirically estimated low natural mortality rate (M = 0.12), and late age at sexual maturity (tm = 9 years for males and females combined) predisposed the L. sebae resource to overfishing. Fish became vulnerable to the gear at a mean size (Lc50 = 39.8 cm LF) and age (3.1 years) before the attainment of sexual maturity at 62 cm LF. Consequently, there was a large proportion of immature fish in landings (51.2% on average) and the full growth potential for the resource might not have been realized. For most years, the fishing mortality rates and SBR approximated the limit reference point F30%. The potential for recruitment-overfishing was identified for some years (1990 and 2004), and the dramatic increase in recent yields is further evidence that management of this fishery requires urgent attention. Previous length-based assessments probably overestimated sustainable harvest rates, which should be between 6.7% and 7.2% of the SBR.
Masks, Minuets and Murder: Images of Italy in Leoncavallo's Pagliacci
Authors: Basini Laura
Published: May 2008

This article interprets Leoncavallo's opera Pagliacci (1892) as a voicing of Italy's ‘Southern Question’ – the problem of the underdeveloped and socially troubled Italian South. Pagliacci juxtaposes cultural symbols that include a commedia dell'arte figure representative of the Italian South and antique genres perceived to be emblematic of ‘civilized’ northern culture. By interpreting the interaction of costumes and musical styles, I argue that the work incorporates images of southern Italy – that ‘violent’, ‘uncontrollable’, yet ‘picturesque’ region – into a broader, northern-dominated conception of Italian nationhood (an interpretative mechanism typical of contemporary image-making media such as magazines and novels).
À la recherche du vrai Socrate
Authors: Dossena Pietro
Published: May 2008

Socrate, Erik Satie's self-acknowledged masterpiece, generated various interpretations but still remains problematic. This article adopts a genetic perspective and, through the analysis of the most interesting ‘key passage’ (bars 46–59 of Le banquet), adds to the understanding of the passage itself (the interpenetration between the figures of Satie, Socrates and Christ as sacrificial victims) and of the work as a whole. In this regard, the category of homogeneity is presented as the most relevant.
Data-driven exploration of ‘spatial pattern-time process-driving forces’ associations of SARS epidemic in Beijing, China
Authors: Wang Jin-Feng , Christakos George , Han Wei-Guo , Meng Bin
Published: April 2008

Background

Severe Acute Respiratory Syndrome (SARS) was first reported in November 2002 in China, and spreads to about 30 countries over the next few months. While the characteristics of epidemic transmission are individually assessed, there are also important implicit associations between them.

Methods

A novel methodological framework was developed to overcome barriers among separate epidemic statistics and identify distinctive SARS features. Individual statistics were pair-wise linked in terms of their common features, and an integrative epidemic network was formulated.

Results

The study of associations between important SARS characteristics considerably enhanced the mainstream epidemic analysis and improved the understanding of the relationships between the observed epidemic determinants. The response of SARS transmission to various epidemic control factors was simulated, target areas were detected, critical time and relevant factors were determined.

Conclusion

It was shown that by properly accounting for links between different SARS statistics, a data-based analysis can efficiently reveal systematic associations between epidemic determinants. The analysis can predict the temporal trend of the epidemic given its spatial pattern, to estimate spatial exposure given temporal evolution, and to infer the driving forces of SARS transmission given the spatial exposure distribution.
DNA replication timing of the human β-globin domain is controlled by histone modification at the origin
Authors: Goren Alon , Tabib Amalia , Hecht Merav , Cedar Howard
Published: April 2008

The human β-globin genes constitute a large chromosomal domain that is developmentally regulated. In nonerythroid cells, these genes replicate late in S phase, while in erythroid cells, replication is early. The replication origin is packaged with acetylated histones in erythroid cells, yet is associated with deacetylated histones in nonerythroid cells. Recruitment of histone acetylases to this origin brings about a transcription-independent shift to early replication in lymphocytes. In contrast, tethering of a histone deacetylase in erythroblasts causes a shift to late replication. These results suggest that histone modification at the origin serves as a binary switch for controlling replication timing.
Interfirm influence strategies and their impact on developing buyer‐supplier relationships
Authors: Chang Hae‐Ching , Lin Chi‐Huang
Published: May 2008

Purpose

The purpose of this paper is to provide a guidance for boundary personnel regarding how to use influence strategies to increase channel satisfaction across relationship development process.

Design/methodology/approach

This paper investigates the use of influence strategies and their impact on channel satisfaction across formation, operation, and maintenance stage from Das and Teng's viewpoint. The sample from Taiwanese manufacture in electronic, information and motors industry involving buyer‐supplier relationships, and asks respondents (sales manager) to select a newer customer to complete a questionnaire for enable sufficient responses to be obtained, representing different stages of the buyer‐supplier relationship.

Findings

The results indicate that the frequency of requests, promises, legalistic pleas, and threat strategies differ significantly among relationship stages. Additionally, information exchange, recommendations, and request strategies have dramatic effect on channel satisfaction across different stages.

Originality/value

This paper proposes the most appropriate model for channel managers to apply influence strategies judiciously in each relationship stage.
The polluted ecosystem game
Authors: Brock W.A. , Dechert W.D.
Published: May 2008

Purpose

The purpose of this paper is to address the issue of optimal management of ecosystems by developing a dynamic model of strategic behavior by users/communities of an ecosystem such as a lake, which is subject to pollution resulting from the users. More specifically, it builds a model of two ecosystems that are spatially connected.

Design/methodology/approach

The paper uses the techniques of optimal control theory and game theory.

Findings

The paper uncovers sufficient conditions under which the analysis of the dynamic game can be converted to an optimal problem for a pseudo authority. It is shown that if the discount rate on the future is high enough relative to ecological self‐restoration parameters then multiple stable states appear. In this case, if the pollution level is high enough it is too costly in terms of what must be given up today to restore the damaged system. By using computational methods, the paper evaluates the relative strengths of lack of coordination, strength of ecosystem self‐cleaning forces, size of discount rates, etc.

Originality/value

The methodology as well as findings can help to devise an optimal management strategy over time for ecosystems.
Paint testing: A survey of some modern techniques
Authors: Boxall J
Published: May 2008

The requirement to test paint arises at every stage in the development and manufacture of coatings though the exact nature of the test procedure varies widely. For example, in the development of a formulation it will be necessary to evaluate changes in the decorative and protective properties of the coating on its substrate, whilst once the product is in production quality control testing will be required. This typically involves rapid evaluation of liquid and dried paint samples to check for conformation to preset limits. A very wide range of techniques are used in these forms of testing though, in general, the equipment and procedures involved are familiar to all paint technologists and include apparatus such as viscometers, glossmeters, colorimeters, hardness testers and artificial weathering machines.
Life after the White Paper
Authors: Maxwell Robert J.
Published: May 2008

This paper reviews the contents of the White Paper — the NHS Review, ‘Working for Patients’ published in January 1989’ — and the initial reactions to it. It is easy to fault the White Paper for its unevenness and incompleteness. On the other hand, just because it leaves so many loose‐ends and is non‐prescriptive in detail, there is scope to fashion what happens next in an experimental, evolutionary way. The author seeks to move the debate on from analysis of the document's strengths and weaknesses to consideration of what those who care about the British National Health Service can do to shape the future that the White Paper has begun to create.
Efficiency and Effectiveness in General Practice
Authors: Szczepura Ala , Davies Carol , Fletcher Joy , Boussofiane Aziz
Published: May 2008

Describes the exploratory use of a statistical technique called data envelopment analysis (DEA), which has been widely used in other parts of the service sector, to measure the efficiency of 52 general practices in three health districts, serving 378,500 patients (78 per cent of the resident population). DEA identified over half (60 per cent) of the 52 practices as less than 100 per cent efficient, with 25 per cent potentially capable of large increases in activity without higher resource levels. There was no significant relationship between efficiency and whether partnerships were training practices, computerized, holding regular meetings, or the total list size, or age structure of practice populations except that multi‐site practices were found to be significantly more efficient as list size increased. DEA efficiency ratings were compared with a proxy for effectiveness (the ability of practices to reach target levels set in the new GP contract). Practices which were below target levels before the new contract was introduced were far less likely to be able to reach these targets once the contract was in place if they had been classified by DEA as 100 per cent efficient (i.e. judged to be unable to achieve greater outputs without increased resources). More research effort now needs to be devoted to exploring the use of DEA in measuring efficiency in general practice, and to examining the relationship between measures of efficiency and effectiveness in primary care.
THE COPPER CONTENT OF THE LIVER OF SOME GAME ANIMALS IN KENYA
Authors: Howard D. A.
Published: April 2008

Summary

The liver copper levels of a number of game animals in Kenya were determined. It was found that the results fell naturally into two fairly distinct groups; for those with simple and those with complex stomachs respectively. The latter, generally speaking, had a higher mean content and a much greater range, with more individual variation. An exception to this was the hippopotamus which appeared to have a much higher content of liver copper than others in the simple stomach group.
THE UTILIZATION OF NATURAL PASTURES BY WILD ANIMALS IN THE RUKWA VALLEY, TANGANYIKA
Authors: Foster Desmond
Published: April 2008

The object of this paper is to elucidate the principles involved in the utilization of natural grasslands by an indigenous community of animals. The studies were carried out in the Rukwa valley during a period of fourteen years and it is suggested that the results are applicable to other similar ecological areas.

The various types of grassland and pasture which occur are described, and their ecology and seasonal development are discussed in relation to the climate and drainage in the valley. The incidence of fire is recorded and its influence is compared with the effects of grazing.

The utilization of the pastures by herbivorous animals is described, and it is explained how grazing pressure results in pasture rejuvenation which is manifest by the development of a grazing mosaic. It is shown that a sequence of animals, heavier ones followed by lighter ones, use the different pastures in rotation during the year and as a consequence alternate periods of optimum use and rest occur, and the harmful effects of over‐grazing do not appear.

The species of animals which form the Rukwa valley grazing community are listed and the ecological stresses which they experience in a changeable environment are noted. Examples are quoted to support the view that dry periods favour the fauna whereas extremely wet ones are unfavourable. It is shown how the ability of the animals to establish biotic pressure on the pastures enables them to become rehabilitated even though conditions remain unfavourable.

It is opined that if the same principles are made use of in game management schemes elsewhere, successful conservation of both grasslands and animals is likely to be achieved.
ON SOCIOLOGY AND BEHAVIOUR IN IMPALA (AEPYCEROS (MELAMPUS LICHTENSTEIN)
Authors: Schenkel Rudolf
Published: April 2008

1. The required habitat of impala, association with other herbivores and the relation to predators are outlined.

2. The commonest types of group formation ‐ female herd with dominant male and bachelor herd ‐ and the factors determining the dynamic aspect of these formations are discussed.

3. The daily activity rhythm is described, distinct activities are charac‐terlised as such and in relation to the social situation.

4. The relationship between the dominant male and the female herd is analysed more closely. The herding activity of the male, the main forms of his courtship, and “roaring”, which occurs in the context of courting and as showing off and threat displays in male rivalry, are described.

5. Social conflict amongst females and bachelors is of short duration and suggests the existence of a social hierarchy within the herds. Severe encounters and fighting occur between rival males exclusively over the possession of a female herd. The different forms of fightings and encounters are summarised and explained on the basis of the proportion of aggressiveness and inhibition of the rivals.

6. Pre‐mating behaviour and copulation are described.

7. The mother‐child bond is outlined in a preliminary form.

8. The special features of impala sociology are discussed and compared with similar behaviour in other bovidae.
FIELD AND LABORATORY METHODS FOR RESEARCH INTO THE ANATOMY OF EAST AFRICAN GAME ANIMALS
Authors: Hofmann R. R.
Published: April 2008

Descriptions are given of various methods which have been used in the field and in the laboratory to obtain and investigate specimens for comparative studies of the anatomy of East African game animals.

Fixation of the animals via the blood vascular system, if possible, with the animal in a natural standing position, is described. Experiences in this respect are recorded in detail, including the preparation of a standing ostrich with its airsac ‐ system unfolded by pumping air into it during infusion of formalin. Emphasis is laid on saving the maximum amount of material from the minimum number of specimens.
FURTHER NOTES ON SOME TEKMITES OF NORTHERN SOMALIA
Authors: Glover P. E.
Published: April 2008

The greater part of the paper consists of descriptions of the different types of termitaria built by Macroter‐mes betticosits in the red sandy soils of Northern Somalia. The tall, rounded sealed type of mound and the tall corneal type with open chimneys were excavated and details of the internal struetnre, especially the form of the fungus gardens and royal chamber, are given. There are notes on associated insects and plante.

The tube‐forming termite Odontoter‐mes classicus I3 discussed briefly, and there are notes on three other species of termite. A discussion of the ecologi‐cal effeets of termites on pastures, with or without the presence of man and his domeatic animais, concludes the paper.
HOME RANGE, BEHAVIOUR, AND RECRUITMENT RATES OF TWO BLACK RHINOCEROS POPULATIONS
Authors: Goddard John
Published: April 2008

During the period 1964 – 1966 biological studies were conducted of two black rhinoeeros Diceros bicornis L. populations in northern Tanzania. One population occupies the caldera of Ngorongoro and the other the area in the vicinity of Olduvai Gorge. Detailed records were made of each rhinoeeros observatson and 182 individuais were seen in the two study areas during the three‐year period.

The black rhinoeeros is a very sedentary species, and the size of the home range is governed by several factors which are described in the^text. The home range of an immature rhinoeeros is larger than that of an adult individual. The adult rhinoeeros, especially the male, is essentially a solitary animal, but immatures frequently join up with a companion.

Activity patterns are described and illustrated, and are similar in the two study areas. Behaviour of the species follows welldefined patterns, and territorial behaviour is uncommon. Vocal communication in the species is described. The significance of dung piles, used regularly by the species, is considered and the results of experiments iflsing faecal samples are described. Relations with two carnivores are discussed.

The recruztment rates of the two populations are almost identical, i.e. 7.0% at Ngorongoro and 7.2% at Olduvai. Various reproductive characteris‐tics affecting recruitment rates, such as age at maturity, gestation period and interval between successive calves are described using records obtained from zoological gardens and from field observations.

The results of the studies indIcate that the rhinoeeros population of the Ngorongoro Conservation Area is considerably higher than was formerly believed. The future of the species in the area appears favourable, providing its habitats are not destroyed through encroaching cultivation.
BASKING BEHAVIOUR OF THE NILE CROCODILE ON CENTRAL ISLAND, LAKE RUDOLF
Authors: Modha M. L.
Published: April 2008

The basking behaviour of the Nile Crocodile on Central Island is discussed in relation to various environmental conditions and compared with the findings of other authorities. This is followed by accounts of the effect of territorial, courting and mating activity on basking patterns, and of interspecific behaviour on basking grounds.
EROSION TERRACES IN THE LOITA‐AITONG AREAS OF KENYA MASAILAND
Authors: Glover P. E. , Wateridge L. E. D.
Published: April 2008

Erosion terraces form a common feature of the landscape in certain plains areas of Kenya and Tanzania. Soil loss from ten terraces, and features associated with it, were assessed over a period of 13 months.

Rainfall alone appeared to have little effect upon undisturbed parts of terrace faces where there was a good grass cover. Trampling and overgrazing by wild or domestic animals, with or without the assistance of rainfall, seemed to be the main causes of cut‐back from terrace faces.
A QUANTITATIVE STUDY OF THE DAILY ACTIVITY OF THE WARTHOG IN THE QUEEN ELIZABETH NATIONAL PARK, UGANDA
Authors: Clough G.
Published: April 2008

Warthog activity was recorded at 4‐min intervals for continuous periods of 14 h on three consecutive days. The major activities were feeding or lying down and walking. The amount of time spent in feeding is related to the size of the animal and maximum‐intensity feeding occurs in the early morning and in the late afternoon and evening. The animals drank usually only once each day. Adult females urinate much more often than males and this is thought to be a behavioural adaptation whereby the males can tell whether or not a female is in heat.
THE REACTION OF A GROUP OF ROTHSCHILD'S GIRAFFE TO A NEW ENVIRONMENT
Authors: Evam E. M. Nesbit
Published: April 2008

The behaviour of a translocated group of 11 Rothschild's giraffe (Giraffa camelopardalis rothschildi Lydekker) was studied for 9 weeks in 1968. A comparison was made between their new and former habitats, the food plants eaten in both places, and behaviour.

For 3 1/2 months after release, they appeared to have settled in the area, but they suddenly started extending their range.

Possible reasons are suggested for their failure to stay in the release area and their eventual disappearance.
USE OF MINERALISED WATER BY KALAHARI WILDLIFE AND ITS EFFECTS ON HABITATS
Authors: CHILD GRAHAM , PARRIS RICHARD , RICHÉ ELIAS LE
Published: April 2008

Summary

This study surveyed the use made by springbok, hartebeest, wildebeest and gemsbok, in particular, of mineralised artificial waterholes along the Nossob river in the southern Kalahari and the effects of this use on the delicate surrounding habitats, as a basis for evaluating the uses and limitations of such water in the management of these species. Taking into account the chemical composition of the dissolved salts in the water; the status of the vegetation and conservation trends near water holes; the relative use made of the waterholes by the antelopes; and land use history, it was concluded that: (a) the animals made regular use of the water, some of which was more mineralised than that recommended for domestic stock, including sheep; (b) there was no relationship between the total dissolved salts and animal use, although there may have been some association between gemsbok use and certain ions; (c) wildlife attracted to boreholes had very little effect on the stability of some surrounding habitats, but may have retarded recovery in areas downgraded by past land use, and (d) under these circumstances the effects of this land use were still amply evident after 21/2 decades.

From this and other evidence, it is suggested that, at the present level of knowledge, mobile wildebeest populations can be stabilised by the provision of relatively potable water, and mineralised water may be used to raise the levels of springbok, hartebeest and gemsbok populations. However, as the water is less of a limiting factor than for species requiring regular drinking water, the increase in density may be relatively limited and so less of a danger to the maintenance of surrounding habitats.
Population structure of olive baboons (Papio anubis (J. P. Fischer)) in the Laikipia District of Kenya
Authors: BERGER MICHAEL E.
Published: April 2008

A study of the population structure of olive baboons {Papio anubis (J. P. Fischer)) was conducted near Rumuruti and Nanyuki in the Laikipia District of Kenya during 1969. The overall male: female ratio was 96:100 for all animals captured. The sex ratio of immature baboons favoured males, while adult females outnumbered adult males. Male baboons demonstrated an increased mortality during the juvenile stage primarily due to exploratory behaviour. Female baboons demonstrated an increased mortality incurred during the first pregnancy or birth early in the adult stage. About 50 % of adult females had an infant offspring, while about 75% had a juvenile offspring. Adult female baboons in their native environment produce an offspring every 2.5‐3.0 years. No birth peak was discernable and births occurred throughout the year.
Growth of the African elephant (Loxodonta africana)
Authors: HANKS J.
Published: April 2008

The three‐stage desk calculation of the von Bertalanffy equation to describe growth in height and weight with age in the elephant is compared with a new approach to calculating the three coefficients in the function by a computer. The two methods give different results with respect to the weight/age calculations. Theoretical von Bertalanffy equations calculated by both methods to describe growth in height and weight with age in the African elephant in Zambia are compared with previously published equations for the elephant in East Africa.

Details are given of growth in height in two known‐age African elephants, a female ‘Diksie’ and a male ‘Kartoum’. Theoretical growth in height curves for the female African and Asiatic elephant are compared. The coefficients K and / for growth in height are not transferable to the growth in weight equations.

Inherent inaccuracies in the calculation of the coefficients in the von Bertalanffy equation are discussed, and it is concluded that in animals which have a long life‐span such as the elephant, the equation serves as a purely empirical representation of weight‐at‐age data and that there is little biological significance in the parameters it contains. The computer‐calculated curves give the best fit to the data. The regression of log age on log shoulder height from 2–20 years of age provides a more realistic approach to comparative growth studies.

The increase in adrenal weight with age is linear.

Tusk growth in relation to age and sex in Zambia is compared with East Africa. It is concluded that the tusks in Zambia are smaller and are more difficult to sex correctly than their East African counterparts, possibly a consequence of the Zambian elephant having a greater degree of tusk wear.

Allometric growth is described with emphasis on the estimation of body weight from shoulder height. The most reliable estimates are obtained from a purely empirical representation of the data, a semilog plot of log body weight on shoulder height.
Age determination of the African buffalo, Syncerus caffer Sparrman
Authors: GRIMSDELL J. J. R.
Published: April 2008

Age criteria for the African buffalo are described. These are based on the tooth eruption sequence and on wear of the first molar. Assignment of absolute ages to the tooth eruption and wear classes has been made by reference to known‐age animals and to numbers of cementum lines in tooth sections. For ageing animals to the nearest year, the normal degree of accuracy of the methods is assumed to be about ± 1/2year (1–5 years of age); about ± 1 year (5–15 years of age); and about ±2 years (15‐20years of age). A field method of age determination is presented based on horn characteristics and relative body size.
Energy budget of the lesser flamingo (Phoeniconaias minor Geoifroy)
Authors: PENNYCUICK C. J. , BARTHOLOMEW G. A.
Published: April 2008

A lesser flamingo's energy surplus, which is defined as the net rate at which it gains chemical energy (averaged over 1 or more whole days) is calculated by estimating the rate at which it filters algae from the water, and then subtracting the energy needed to pump water through the filter, and that expended on general metabolism.

From the assumptions made, it follows that a flamingo should be able to make a positive energy surplus if the food concentration exceeds about 0–12 kg dry matter per m3 of water, and if it spends 80% of its time feeding. During incubation, however, less than half the total time can be spent feeding, and in this case the food concentration would need to be at least 0–25 kg/m3. About 2 days would be required to produce an egg at this concentration, and less than 1 day at the highest concentrations observed.