bluuebunny/crossref_metadata_2025 huggingface dataset:
Approximate analysis for buckling of compression loaded long rectangular plates with flexural/twist anisotropy
Authors: Weaver P.M
Published: November 2005

Approximate expressions for buckling loads of long rectangular plates with flexural/twist anisotropy and simply supported edges are derived. The novelty of the current approach lies in the use of bounded non-dimensional quantities to reduce the complexity of formulation to such a state that closed form solutions are possible. Such expressions are validated with respect to detailed finite element analysis and numerical solutions found in the literature. A number of studies are conducted using a composite material with extremely large ply stiffness in the fibre direction and whose layers are arranged into extreme stacking sequences. Such an arrangement maximizes anisotropic effects and so challenges the validity of the solutions in a most testing manner. Despite such extreme studies excellent agreement is found.
Endogenous timing in competitive interactions among relatives
Authors: Cant Michael A , Shen Sheng-Feng
Published: November 2005

Most evolutionary game theory models solve for equilibrium levels of some behaviour on the restrictive assumptions that players choose their actions simultaneously, and that a player cannot change its action after observing that of its opponent. An alternative framework is provided by sequential or ‘Stackelberg’ games in which one player commits to a ‘first move’ and the other has an opportunity to observe this move before choosing its response. Recent interest in the economic literature has focused on Stackelberg games which exhibit ‘endogenous timing’, i.e. games in which a leader and a follower arise spontaneously as a consequence of each player attempting to maximize its reward. Here, we provide the first demonstration of endogenous timing in an evolutionary context using a simple model of resource competition (the ‘tug-of-war’ model). We show that whenever two related individuals compete for a share of communal resources, both do best to adopt distinct roles in a sequential game rather than engage in simultaneous competition. Somewhat counterintuitively, the stable solution is for the weaker individual to act as leader and commit to a first move, because this arrangement leads to a lower total effort invested in competition. Endogenous timing offers a new explanation for the spontaneous emergence of leaders and followers in social groups, and highlights the benefits of commitment in social interaction.
Both social and ecological factors predict ungulate brain size
Authors: Shultz Susanne , Dunbar R.I.M
Published: November 2005

Among mammals, the members of some Orders have relatively large brains. Alternative explanations for this have emphasized either social or ecological selection pressures favouring greater information-processing capacities, including large group size, greater foraging efficiency, higher innovation rates, better invasion success and complex problem solving. However, the focal taxa for these analyses (primates, carnivores and birds) often show both varied ecological competence and social complexity. Here, we focus on the specific relationship between social complexity and brain size in ungulates, a group with relatively simple patterns of resource use, but extremely varied social behaviours. The statistical approach we used, phylogenetic generalized least squares, showed that relative brain size was independently associated with sociality and social complexity as well as with habitat use, while relative neocortex size is associated with social but not ecological factors. A simple index of sociality was a better predictor of both total brain and neocortex size than group size, which may indicate that the cognitive demands of sociality depend on the nature of social relationships as well as the total number of individuals in a group.
The dilemma of female mate selection in the brown bear, a species with sexually selected infanticide
Authors: Bellemain Eva , Zedrosser Andreas , Manel Stéphanie , Waits Lisette P , Taberlet Pierre , Swenson Jon E
Published: November 2005

Because of differential investment in gametes between sexes, females tend to be the more selective sex. Based on this concept, we investigate mate selection in a large carnivore: the brown bear (Ursus arctos). We hypothesize that, in this species with sexually selected infanticide (SSI), females may be faced with a dilemma: either select a high-quality partner based on phenotypic criteria, as suggested by theories of mate choice, or rather mate with future potentially infanticidal males as a counter-strategy to SSI. We evaluated which male characteristics were important in paternity assignment. Among males available in the vicinity of the females, the largest, most heterozygous and less inbred and also the geographically closest males were more often the fathers of the female's next litter. We suggest that female brown bears may select the closest males as a counter-strategy to infanticide and exercise a post-copulatory cryptic choice, based on physical attributes, such as a large body size, reflecting male genetic quality. However, male–male competition either in the form of fighting before copulation or during the post-copulatory phase, in the form of sperm competition, cannot entirely be ruled out.
CO2 enrichment and carbon partitioning to phenolics: do plant responses accord better with the protein competition or the growth differentiation balance models?
Authors: J. Mattson W. , Julkunen‐Tiitto R. , Herms D. A.
Published: November 2005

Rising levels of atmospheric CO2 can alter plant growth and partitioning to secondary metabolites. The protein competition model (PCM) and the extended growth/differentiation balance model (GDBe) are similar but alternative models that address ontogenetic and environmental effects on whole‐plant carbon partitioning to the phenylpropanoid biosynthetic pathway, making many divergent predictions. To test the validity of the models, we compare plant responses to one key prediction: if CO2 enrichment simultaneously stimulates both photosynthesis and growth, then PCM predicts that partitioning to phenolic compounds will decline, whereas GDBe generally predicts the opposite. Elevated CO2 (at 548 ppm) increased the biomass growth (ca 23%) as well as the net photosynthesis (ca 13%) of 1‐year‐old potted paper birch, Betula papyrifera Marsh., in a free air carbon dioxide enrichment study (FACE) in northern Wisconsin. Concomitantly, elevated CO2 increased carbon partitioning to all measured classes of phenolics (Folin‐Denis phenolics, HPLC low molecular weight phenolics (i.e. cinnamic acid derivatives, flavonol glycosides, and flavon‐3‐ols), condensed tannins, and acid‐detergent lignin) in leaves. In stem tissues, tannins and lignin increased, but F‐D phenolics did not. In root tissues, F‐D phenolics, and tannins increased, but lignin did not. The data suggest that CO2 enrichment stimulated pathway‐wide increase in carbon partitioning to phenylpropanoids. High CO2 plants had 11.8% more F‐D phenolics, 19.3% more tannin, and 10% more lignin than ambient plants after adjusting for plant mass via analysis of covariance. In general, the results unequivocally support the predictions of the GDBe model. By way of contrast, results from many parallel studies on FACE trembling aspen, Populus tremuloides Michx., suggest that although CO2 enrichment has consistently stimulated both photosynthesis and growth, it apparently did not generally stimulate pathway‐wide increases, or decreases, in carbon partitioning to phenylpropanoids in leaves and wood, but rather has specifically, though not consistently, increased partitioning to foliar phenolic glycosides. Likewise, in this case, GDBe's predictions better accord with the FACE aspen data than PCM's. If further tests of the two models also support GDB rather than PCM, then PCM's main assumption (whole‐plant N rather than C is limiting partitioning to phenolic synthesis) may be incorrect.
The influence of a parasite community on the dynamics of a host population: a longitudinal study on willow ptarmigan and their parasites
Authors: Holmstad P. R. , Hudson P. J. , Skorping A.
Published: November 2005

Despite the fact that most host populations are infected by a community of different parasite species, the majority of empirical studies have focused on the interaction between the host and a single parasite species. Here, we explore the hypothesis that host population dynamics are affected both by single parasite species and by the whole parasite community. We monitored population density and breeding productivity of two populations of willow ptarmigan (Lagopus lagopus) in northern Norway for 8 and 11 years, respectively, and sampled eukaryotic endoparasites. We found that increasing abundances of the cestodeHymenolepis micropswas associated with increased breeding mortality and reduced annual growth rate of the host population in both areas, and reduced host body mass and body condition in the area where such data were available. In one of the areas, the abundance of the nematodeTrichostrongylus tenuiswas associated with reductions in host body mass, body condition and breeding mortality and the filaroid nematodeSplendidofilaria papillocercawas negatively related to host population growth rates. The parasite community was also negatively related to host fitness parameters, suggesting an additional community effect on host body mass and breeding mortality, although none of the parasites had a significant impact on their own. The prevalence of parasites with very different taxonomical origins tended to covary within years, suggesting that variability in the parasite community was not random, but governed by changes in host susceptibility or environmental conditions that affected exposure to parasites in general. Other variables including climate, plant production and rodent densities were not associated with the recorded demographic changes in the host population.
Negative plant–soil feedback and species coexistence
Authors: Bonanomi Giuliano , Giannino Francesco , Mazzoleni Stefano
Published: November 2005

Different mechanisms, including equilibrium and non‐equilibrium processes, have been taken into account as possible theoretical explanations of species coexistence. Despite the ample evidence on the existence of negative plant–soil feedback in both agriculture and natural vegetation, the role of these processes in the organization and dynamics of plant communities has so far been neglected. In this study, simulations by an individual‐based competition model show how the intensity of negative feedback on individual plant performance can produce faster successional dynamics and allow species coexistence in two‐ and multi‐species systems. The results show that even low levels of negative plant–soil feedback can enable species coexistence and often produce cyclic population dynamics. Moreover, the model highlights how negative feedback can generate positive reciprocal interspecific interactions at the population level, despite the fact that only competitive interactions is present between individual plants. In fact, competitive effects occur on a short‐term scale, but positive reciprocal species interactions emerge only if negative feedback affects all species and if longer periods of simulation, more than the species life span, are considered. An important outcome of the model is the evidence that the effects at population level are timescale‐dependent, thus showing the limitation of short‐term species removal experiments used in traditional competition studies.
Time and energy constraints in demanding phases of the annual cycle: an example of time limitation in refuelling migratory swans
Authors: Nolet Bart A. , Klaassen Marcel
Published: November 2005

The daily metabolizable energy intake of an animal is potentially limited by either the available feeding time or by its capacity to process energy. Animals are generally considered not to be time‐limited but rather to be energy‐processing‐limited. This is concluded from the common observation that an animal's feeding time per day increases with a decrease in food density. We argue that such changes in feeding time are in theory also expected when no constraints are operating. Thus, a study of the constraints on energy intakes of free‐living animals should be performed during demanding phases of the year. As an example, we collected data on time and energy budgets of Bewick's swan (Cygnus columbianus bewickii) refuelling during migration on fennel pondweed (Potamogeton pectinatus) tubers in two years differing two‐fold in tuber biomass density. As predicted by time limitation, the feeding time (defined as the time with the head submerged) did not change in response to a change in food biomass density, both within and between years (averaging 12.2 h d−1). Contrary to energy‐processing limitation, and again in line with time limitation, the daily metabolizable energy intake varied, being greater in the year with high than in the year with low food densities. We conclude that more studies are needed of animals operating under demanding conditions before it can be assessed whether free‐living animals are generally energy‐processing‐ or time‐limited.
Does group foraging promote efficient exploitation of resources?
Authors: Beauchamp Guy
Published: November 2005

Increased avoidance of food patches previously exploited by other companions has been proposed as one adaptive benefit of group foraging. However, does group foraging really represent the most efficient way to exploit non‐ or slowly‐renewing resources? Here, I used simulations to explore the costs and benefits of exploiting non‐renewing resources by foragers searching for food patches independently or in groups in habitats with different types of resource distribution. Group foragers exploited resources in a patch more quickly and therefore spent proportionately more time locating new patches. Reduced avoidance of areas already exploited by others failed to overcome the increased time cost of searching for new food patches and group foragers thus obtained food at a lower rate than solitary foragers. Group foraging provided one advantage in terms of a reduction in the variance of food intake rate. On its own, reduced avoidance of exploitation competition through group foraging appears unlikely to increase mean food intake rate when exploiting non‐renewing patches but may provide a way to reduce the risk of an energy shortfall.
Juvenile growth and survival under dietary restriction: are males and females equal?
Authors: Le Galliard J.‐F. , Ferrière R. , Clobert J.
Published: November 2005

The effects of food availability on life‐history traits may be direct or delayed and may vary between the sexes. We evaluated the effects of dietary restriction early in life on growth and survival of male and female juveniles in the common lizard (Lacerta vivipara) and surveyed the literature on sex‐specific sensitivity to the environment in vertebrates. Juvenile lizards were reared in the laboratory during one month following birth under full feeding or under dietary restriction. They were then released in two outdoor enclosures, where we compared growth and survival between treatments during one year. Low food availability early in life led to lower body growth in a direct, but not delayed, manner. The absence of compensatory growth in juveniles that experienced dietary restriction might be explained by their reduced competitiveness. Dietary restriction had a strongly negative, delayed effect on survival up to the age of one year that was mediated by selection against smaller individuals. Effects of dietary restriction were not sex‐specific, as expected from the similar energetic requirements of male and female juveniles. Hence, food availability has long‐lasting consequences on life‐history traits that might influence population dynamics in this species.
The experience of a man with severe challenging behaviour following resettlement from hospital: a single case design
Authors: Bissell Lianne , Phillips Neil , Kroese Biza Stenfert
Published: November 2005

Carers’ behaviour is thought to contribute to the development and maintenance of challenging behaviour in people with learning disabilities (Emersonet al.1995;Hastings & Remington 1994). The present study sought to investigate the effectiveness of a behavioural intervention in the management of such problem behaviours by means of a long‐term follow‐up single case study. This study describes the prevalence and management of the severe challenging behaviours of a 55‐year‐old man, (Paul)1, with severe learning disabilities. The functional assessment showed a significant decrease in challenging behaviour after implementation of guidelines. However, effective dental treatment produced a further reduction in challenging behaviour, posing many implications for healthcare assessment and practice. The results of this single case study are discussed in the context of relocation practices, holistic assessment and service provision.
Hunting behaviour in West African forest leopards
Authors: Jenny David , Zuberbühler Klaus
Published: November 2005

The leopard (Panthera pardus) is a major predator of mammals within the rainforest ecosystem of West Africa. Most of the available information on leopard hunting behaviour comes from studies conducted in open savannah habitats, while little is known about forest leopards. Our radio‐tracking data and scat analysis show that forest leopards differ in various ways from the savannah populations. Forest leopards are diurnal and crepuscular hunters who follow the activity pattern of their prey species. They exhibit seasonal differences in activity patterns, and they develop highly individualized prey preferences. These findings challenge the widespread notion of leopards as opportunistic nocturnal predators.
Tree formations in relation with soil and grasses in a dry savanna in Mali, West Africa
Authors: Picard Nicolas , Guéguen Katell , Abdoulaye Haroun A. , Diarisso Dalla , Karembé Moussa , Birnbaum Philippe , Nasi Robert
Published: November 2005

The relationship between trees, grass and soil in a dry savanna in Mali was investigated, to identify variables that are most relevant to assess vegetation units. A 65 ha plateau was inventoried using a systematic square grid sampling pattern. Thirteen soil or topography variables, and tree and grass characteristics were measured at each sampling point. Multivariate analysis was used to separately analyse soil, tree and grass data, and to characterize tree–grass and tree–soil relationships. Four units of soils, four units of tree formations, and four units of grass formations were identified. There was a correspondence between these groups, indicative of four vegetation units: thicket, bare land, shrub savanna and tree savanna. Soil depth and soil texture were the soil variables that best related to tree vegetation. A negative correlation was found between tree basal area and grass dry biomass. Finally, vegetation units, as identified from tree species composition, had contrasted diameter structures and densities.
Estimating age of immobilized elephants from teeth impressions using dental silicon
Authors: Rasmussen Henrik Barner , Wittemyer George , Douglas‐Hamilton Iain
Published: November 2005

High precision condensation dental silicon, ZetalaborTM, was used to create moulds of the lower jaw molars from 22 immobilized African elephants (Loxodonta africana Blumenback) during radio collaring operations. These moulds were used to determine the elephant's age using Laws and Jachmann's molar aging criteria. The technique proved easy and fast and produced useful imprints in 90% of the cases. We found our age estimates, based on physical appearance, made prior to immobilizations were relatively accurate, with 75% within ±3 years and 95% within ±5 years from the age indicated from molar evaluation. When re‐collaring the same individuals in 2–3 years, new moulds will be made to compare a known time period with the degree of tooth wear. This will provide verification of Laws age estimates from free‐ranging elephants.
Competitive interactions between spotted hyenas and lions in the Etosha National Park, Namibia
Authors: Trinkel Martina , Kastberger Gerald
Published: November 2005

Spotted hyenas are successful hunters, but they also scavenge. Their main food competitors are lions. In the Etosha National Park, Namibia hyenas are unable to prevent kleptoparasitism by lions and fail to acquire kills from lions. The reasons are the small ratio of hyenas to female and subadult lions at kills and the presence of adult male lions. Because of the hyenas’ small clan sizes and large territories they seem to be unable to recruit sufficient clan members to take over lion kills or deter lions from their own kills. In Etosha, 71% of hyena mortality was due to lions; four cubs and one adult female hyena were killed by male lions during a 1‐year study. Hyenas have evolved adaptations against lions and initiate aggressive interactions with lions without the immediate availability of food, which is termed mobbing behaviour. Etosha hyenas initiated mobbing attempts when lions were near the hyena's communal den. Possibly, Etosha hyenas mobbed lions to distract lions from the hyenas’ den and their cubs and to warn their dependent offspring to hide from lions.
Variability of zooplankton community along a section of the Upper Victoria Nile, Uganda
Authors: Mwebaza‐Ndawula L. , Sekiranda S. B. K. , Kiggundu V.
Published: November 2005

Zooplankton community along a stretch of Upper Victoria Nile was investigated at selected sites between Kalange and Namasagali during April, August and October 2000 as part of a wider ecological study to generate biological baseline data prior to construction of a hydropower plant at Dumbbell Island. The study provided an opportunity to investigate a riverine zooplankton community for comparison with the more studied lake communities. Field sampling was made with a plankton net of 25 cm mouth opening and 60 μm nitex mesh; fitted with sandbags for ease of operation in water currents. Zooplankton subsamples were examined under an inverted microscope at ×100 magnification. The 27 species encountered belong to three broad taxonomic groups: Copepoda, Cladocera and Rotifera. Rotifers had the highest number of species (sixteen) followed by copepods (six). Species richness and total numerical abundance were high at the two upstream sites and decreased significantly downstream. High zooplankton densities at upstream sites during April plummeted to much lower levels in August and October. By comparison, species richness and numerical abundance were much lower than those of Lake Victoria; the ultimate source of the Upper Victoria Nile water. This may be due to differences between lotic and lentic habitats as both physical and biological processes are known to be limited under flowing water conditions. The high species richness and numerical abundance at the two upstream sites may be due to positioning of sampling points downstream of islands and/or rock outcrops for ease of net sampling as well as a richer food environment observed in a parallel study of algal biomass. The type and level of impacts of the proposed hydropower station on biological communities will be determined by site location: either upstream or downstream of the plant. Monitoring surveys of both environment and biological parameters during and after construction of the power plant will be necessary to keep track of ecosystem changes and their implications.
Long‐term follow‐up of collagenous colitis after induction of clinical remission with budesonide
Authors: MIEHLKE S. , MADISCH A. , VOSS C. , MORGNER A. , HEYMER P. , KUHLISCH E. , BETHKE B. , STOLTE M.
Published: November 2005

Background:  Budesonide (Entocort) is effective for the treatment of collagenous colitis.

Aim:  To assess the long‐term outcome of patients after induction of clinical remission by budesonide treatment.

Methods:  Fifty‐one patients with chronic diarrhoea and histologically proven collagenous colitis were enrolled in randomized, placebo‐controlled crossover trial using budesonide 9 mg daily for 6 weeks. Patients in clinical remission after either initial or crossover budesonide treatment were followed using standardized questionaires. Clinical relapse was defined as five or more loose stools/day for at least 4 consecutive days.

Results:  A total of 33 patients achieved clinical remission (85% per‐protocol). During a median follow‐up of 16 months, clinical relapse occurred in 20 patients (61%), after a median time of 2 weeks (range: 1–104, mean: 10 weeks). Patient age <60 years was identified as a significant risk factor for clinical relapse (OR = 7.4, P = 0.048). Budesonide was used for treatment of clinical relapse in 80% of patients achieving clinical response in all of them.

Conclusions:  Budesonide is effective in the treatment of collagenous colitis. Clinical relapses may occur in a considerable number of patients, particularly in those <60 years. Treatment of clinical relapse with budesonide appears to be an effective option.
Systematic review: the model for end‐stage liver disease – should it replace Child‐Pugh's classification for assessing prognosis in cirrhosis?
Authors: CHOLONGITAS E. , PAPATHEODORIDIS G. V. , VANGELI M. , TERRENI N. , PATCH D. , BURROUGHS A. K.
Published: November 2005

Background:  Prognosis in cirrhotic patients has had a resurgence of interest because of liver transplantation and new therapies for complications of end‐stage cirrhosis. The model for end‐stage liver disease score is now used for allocation in liver transplantation waiting lists, replacing Child‐Turcotte‐Pugh score. However, there is debate as whether it is better in other settings of cirrhosis.

Aim:  To review studies comparing the accuracy of model for end‐stage liver disease score vs. Child‐Turcotte‐Pugh score in non‐transplant settings.

Results:  Transjugular intrahepatic portosystemic shunt studies (with 1360 cirrhotics) only one of five, showed model for end‐stage liver disease to be superior to Child‐Turcotte‐Pugh to predict 3‐month mortality, but not for 12‐month mortality. Prognosis of cirrhosis studies (with 2569 patients) none of four showed significant differences between the two scores for either short‐ or long‐term prognosis whereas no differences for variceal bleeding studies (with 411 cirrhotics). Modified Child‐Turcotte‐Pugh score, by adding creatinine, performed similarly to model for end‐stage liver disease score. Hepatic encephalopathy and hyponatraemia (as an index of ascites), both components of Child‐Turcotte‐Pugh score, add to the prognostic performance of model for end‐stage liver disease score.

Conclusions:  Based on current literature, model for end‐stage liver disease score does not perform better than Child‐Turcotte‐Pugh score in non‐transplant settings. Modified Child‐Turcotte‐Pugh and model for end‐stage liver disease scores need further evaluation.
Personal view: why is my GI clinic filled with surgical mishaps? Post‐operative syndromes as an externality problem
Authors: SONNENBERG A.
Published: November 2005

The aim of the present analysis was to review why gastroenterology clinics appear filled with patients suffering from postsurgical syndromes.

The long‐term sequelae of gastrointestinal surgery can be modelled as a negative production externality of surgical operations.

When seeking to maximize their profits, surgeons are primarily concerned with the price and cost of surgery alone. They tend to ignore parts of the ensuing long‐term costs they impose through postsurgical syndromes on other medical specialties. The complication‐related rise in the cost of gastroenterology practice reflects parts of the societal costs of surgery that are not included on the surgical balance sheet. To the surgeon, surgery appears cheaper than to the rest of the medical community, because cost shifting from surgery to other medical specialties leads to a favourable surgical outcome with more surgical operations performed than medically needed or economically feasible.

The amount of surgical sequelae could drop, if surgeons were forced to care for all their own postsurgical syndromes or if surgery entered a joint enterprise with gastroenterology caring for the same patient pool.
Evaluation of capsaicin ointment at the Korean hand acupressure point K‐D2 for prevention of postoperative nausea and vomiting
Authors: Agarwal A. , Dhiraaj S. , Tandon M. , Singh P. K. , Singh U. , Pawar S.
Published: November 2005

The K‐D2 point is the Korean hand acupressure point in Koryo Hand Therapy for prevention of postoperative nausea and vomiting. We evaluated the efficacy of capsaicin ointment at the K‐D2 point in 186 patients undergoing laparoscopic cholecystectomy in a randomised, prospective, double‐blind and placebo‐controlled study. Patients were randomised to have either placebo ointment or capsaicin ointment applied to the K‐D2 point of both hands 1 h before surgery under standardised anaesthesia. The ointment was removed 8 h later. Postoperative nausea and vomiting was evaluated 6 and 24 h following surgery. The incidence of postoperative nausea and vomiting was lower in the capsaicin group, with an absolute risk reduction (ARR) of 21%, a relative risk reduction (RRR) of 50% and a number‐needed‐to‐treat (NNT) of 5 at 0–6 h (p = 0.001), and an ARR of 11%, a RRR of 85% and a NNT of 9 at 6–24 h (p = 0.003). The need for rescue anti‐emetic treatment was also lower at 0–6 h (3 (3%) vs 11 (12%); p = 0.04) and at 6–24 h (5 (5%) vs 0; p = 0.02).
Effects of stream restoration and management on plant communities in lowland streams
Authors: PEDERSEN TINA CHARLOTTE MOUSTGAARD , BAATTRUP‐PEDERSEN ANNETTE , MADSEN TOM VINDBÆK
Published: November 2005

1. We evaluated restoration success on macrophyte species diversity and composition in lowland streams using communities in 30 naturally meandering stream reaches in the western part of Jutland, Denmark, as reference target communities. Fuzzy set clustering was used to examine the floristic and environmental similarity among reaches, whereas fuzzy set ordination was used to relate floristic patterns to environmental variables.

2. Two major groups of streams were identified based on their floristic composition. One group consisted of reference and restored reaches and the other of the majority of channelised reaches. We found that management exerted a strong influence on the macrophyte communities and that the identified groups were related to differences in management intensity.

3. Our results also indicate that bank morphology and bed level affected macrophyte communities in the streams, particularly the richness and abundance of terrestrial species. The analyses performed suggest that shallow and wide banks allow for a larger migration of species from the stream banks into the streams, thereby enhancing species diversity within the stream channel.

4. The results of this study suggest that macrophyte communities in channelised lowland streams can recover following restorative interventions given that stream management (i.e. weed cutting and dredging) is minimised and that stream banks are reprofiled to improve the lateral connectivity between the stream and its valley.
Further comment on drag and reconfiguration of macrophytes
Authors: GREEN JULIAN C.
Published: November 2005

1. The paper by Sand‐Jensen (2003, Freshwater Biology, 48, 271), and the subsequent comment and reply (Sukhodolov, 2005, Freshwater Biology, 50, 194; Sand‐Jensen, 2005, Freshwater Biology, 50, 196), are discussed. I present partial theory describing how the macrophyte bending angle changes with increased flow velocity, demonstrating a nonlinear relation.

2. While Sand‐Jensen (2005) is correct that plant wetted area is the only characteristic area that can be measured easily, some other measure of the exposure area of the plant stand to the flow may be preferable. The relationship in Sand‐Jensen (2003) between the dimensionless drag coefficient and flow velocity depends on the definition of characteristic area. Hence, the analysis involving the drag parameter in Sand‐Jensen (2003) should be interpreted with care.
The effects of an unpredictable precipitation regime on vernal pool hydrology
Authors: BAUDER E. T.
Published: November 2005

1. Vernal pools are small precipitation‐fed temporary wetlands once common in California. They are known for their numerous narrowly endemic plant and animal species, many of which are endangered. These pools experience the typical wet season/dry season regime of Mediterranean climates. Their hydrological characteristics are determined by a complex interaction between the highly variable climate and topographic relief.

2. Hypotheses regarding the effects on ponding of total precipitation, storm intensity and pattern were examined using long‐term weather records combined with two decades of data on the length and depth of inundation in 10 individual pools. Similarly, data on pool landscape position and microtopography allowed examination of the interactions between topography and rainfall amount and pattern.

3. The total amount of precipitation and length of inundation were strongly correlated. Landscape position affected ponding duration, with collector pools holding water longer than headwater pools. Basin microtopography interacted with climatic variability to determine the nature and extent of within‐basin microhabitats sufficiently different in hydrological and/or soil conditions to support or exclude individual species. The effect on hydroperiod of precipitation concentrated in a few months rather than spread more evenly over the season depended on total precipitation.

4. Changes in climate, the mound‐and‐depression landscape or pool microtopography could have profound impacts on the hydrology of individual pools as well as the array of hydrological conditions in the system. Given the individualistic responses of the numerous endemic species supported by vernal pools, any of these environmental changes could diminish their sustainability and increase the risk of species extinction. Conservation, restoration and management decisions should take these factors into account.
Finite‐difference modelling of wave propagation in acoustic tilted TI media
Authors: Zhang Linbin , Rector James W. , Hoversten G. Michael
Published: November 2005

Based on an acoustic assumption (that the shear‐wave velocity is zero) and a dispersion relationship, we derive an acoustic wave equation for P‐waves in tilted transversely isotropic (TTI) media (transversely isotropic media with a tilted symmetry axis). This equation has fewer parameters than an elastic wave equation in TTI media and yields an accurate description of P‐wave traveltimes and spreading‐related attenuation. Our TTI acoustic wave equation is a fourth‐order equation in time and space. We demonstrate that the acoustic approximation allows the presence of shear waves in the solution. The substantial differences in traveltime and amplitude between data created using vertical transversely isotropic (VTI) and TTI assumptions is illustrated in examples.
Simulation of two‐phase fluid flow through compactible reservoirs
Authors: Grechka Vladimir , Soutter Leigh
Published: November 2005

Fluid‐flow simulators used in the oil industry model the movement of fluids through a porous reservoir rock. These simulators either ignore coupling between the flow and concurring deformation of the solid rock frame or take it into account approximately, in the so‐called loose or staggered‐in‐time mode. In contrast to existing simulators, the one we describe here fully couples two‐phase (oil and water) flow to subsurface deformation and simultaneously accounts for all relevant physical phenomena. As such, our flow simulator inherently links time‐dependent fluid pressures, saturations, permeabilities and flow velocities to stresses in the whole subsurface. These stresses relate to strains through the non‐linear theory of elasticity, allowing us to model time‐lapse changes in seismic velocities and anisotropy. The velocity variations manifest themselves in time shifts and reflection amplitudes that are conventionally measured from 4D seismic data. Changes in anisotropy produce time‐dependent shear‐wave splitting that can be used for monitoring the horizontal stresses.
The ethics of research using electronic mail discussion groups
Authors: Kralik Debbie , Warren Jim , Price Kay , Koch Tina , Pignone Gino
Published: November 2005

Aim.  The aim of this paper is to identify and discuss the ethical considerations that have confronted and challenged the research team when researchers facilitate conversations using private electronic mail discussion lists.

Background.  The use of electronic mail group conversations, as a collaborative data generation method, remains underdeveloped in nursing. Ethical challenges associated with this approach to data generation have only begun to be considered. As receipt of ethics approval for a study titled; ‘Describing transition with people who live with chronic illness’ we have been challenged by many ethical dilemmas, hence we believe it is timely to share the issues that have confronted the research team. These discussions are essential so we can understand the possibilities for research interaction, communication, and collaboration made possible by advanced information technologies.

Discussion.  Our experiences in this study have increased our awareness for ongoing ethical discussions about privacy, confidentiality, consent, accountability and openness underpinning research with human participants when generating data using an electronic mail discussion group. We describe how we work at upholding these ethical principles focusing on informed consent, participant confidentiality and privacy, the participants as threats to themselves and one another, public–private confusion, employees with access, hackers and threats from the researchers.

Conclusion.  A variety of complex issues arise during cyberspace research that can make the application of traditional ethical standards troublesome. Communication in cyberspace alters the temporal, spatial and sensory components of human interaction, thereby challenging traditional ethical definitions and calling to question some basic assumptions about identity and ones right to keep aspects of it confidential. Nurse researchers are bound by human research ethics protocols; however, the nature of research by electronic mail generates moral issues as well as ethical concerns. Vigilance by researchers is required to ensure that data are viewed within the scope of the enabling ethics approval.
Agitation in dementia: concept clarification
Authors: Kong Eun‐Hi
Published: November 2005

Aim. The aim of this paper is to clarify the concept of agitation in dementia through analysing definitions, critical attributes, components, boundaries, antecedents and consequences of agitation.

Background. The concept of agitation is not well defined. In addition, there exists much confusion about the characteristics and boundaries of agitation, as well as the distinction between agitation and related concepts. Recently developed theoretical models for agitation in dementia require new interpretation and conceptualization of agitation.

Methods. Morse's method of critical appraisal of the literature was used. In addition, some parts of Rodgers’ evolutionary method were employed. Data were selected using six electronic databases and the key words ‘agitation’, ‘agitated’, ‘dementia’, ‘demented’ and ‘Alzheimer’. The analysis included 86 empirical or theoretical papers and one book.

Results. A transition from the observer's perspective to the patient's perspective in the interpretation of agitation was found. Five critical attributes of agitation in dementia were identified: excessive, inappropriate, repetitive, non‐specific and observable. Patient factors, interpersonal factors, environmental factors and restraint were identified as precipitating antecedents. Mediating antecedents included discomfort, unmet need and misinterpretation. Consequences of agitation were identified at the levels of patient, caregiver and others.

Conclusions. This transition in perspectives has important implications as it can change health providers’ attitudes and responses to agitation and lead to patient‐focused and individualized care. Researchers and clinicians are encouraged to avoid labelling agitated behaviour as ‘disturbing behaviour’.
Packaging: a grounded theory of how to report physiological deterioration effectively
Authors: Andrews Tom , Waterman Heather
Published: November 2005

Aim.  The aim of this paper is to present a study of how ward‐based staff use vital signs and the Early Warning Score to package physiological deterioration effectively to ensure successful referral to doctors.

Background.  The literature tends to emphasize the identification of premonitory signs in predicting physiological deterioration. However, these signs lack sensitivity and specificity, and there is evidence that nurses rely on subjective and subtle indicators. The Early Warning Score was developed for the early detection of deterioration and has been widely implemented, with various modifications.

Method.  The data reported here form part of a larger study investigating the practical problems faced by general ward staff in detecting physiological deterioration. During 2002, interviews and observations were carried out using a grounded theory approach, and a total of 44 participants were interviewed (30 nurses, 7 doctors and 7 healthcare support workers).

Findings.  Participants reported that quantifiable evidence is the most effective means of referring patients to doctors, and the Early Warning Score achieves this by improving communication between professionals. Rather than reporting changes in individual vital signs, the Early Warning Score effectively packages them together, resulting in a much more convincing referral. It gives nurses a precise, concise and unambiguous means of communicating deterioration, and confidence in using medical language. Thus, nurses are empowered and doctors can focus quickly on identified problems.

Conclusion.  The Early Warning Score leads to successful referral of patients by providing an agreed framework for assessment, increasing confidence in the use of medical language and empowering nurses. It is essential that nurses and nursing students are supported in its use and in developing confidence in using medical language by continued emphasis on physiology and pathophysiology in the nursing curriculum.
Hope seen through the eyes of 10 Australian young people
Authors: Turner De Sales
Published: November 2005

Aim.  The aim of this paper is to report the findings of a phenomenological study that explored hope in 10 young people in Australia.

Background.  Evidence suggests many Australian young people are in crisis. Examination of key reports that detail the incidence of suicide, early drug‐taking behaviours, homelessness, self‐harm behaviours, joblessness, depressive disorders, crime statistics and alcohol abuse suggest that many of today's young people have lost resilience as well as vital connections to their community.

Method.  Two methods were employed to encourage the participants to reflect on their experiences of hope – what it is and what it meant to them. The first was to supply participants with a disposable colour film camera and ask them to take pictures that, in their view, showed hope. The second was participation in an in‐depth interview that was prompted in part, by their photographs. Interview audiotapes were transcribed verbatim and analysis of the text used the Turner method. The data were collected in 2002.

Findings.  Four horizons of hope were revealed: at‐one‐with; a driving force; having choices; and connecting and being connected. These horizons are discussed, showing how, or if, the literature treats these dimensions of hope. Perspectives are offered on how they might be considered by nurses who are charged with caring for today's young people.

Conclusion.  Registered Nurses who work with young people must understand the phenomenon of hope from their unique perspective before they can offer appropriate hope‐facilitating strategies.
Interannual variation in the post‐weaning and juvenile survival of subantarctic fur seals: influence of pup sex, growth rate and oceanographic conditions
Authors: BEAUPLET GWÉNAËL , BARBRAUD CHRISTOPHE , CHAMBELLANT MAGALY , GUINET CHRISTOPHE
Published: November 2005

A major hypothesis of life history theory is that early development conditions affect future survival and reproductive success. However, although a growing number of studies have addressed this question, many of them are taxonomically biased, thereby impeding the generalization of this hypothesis.

This study examines the factors influencing post‐weaning survival in five weaned cohorts of subantarctic fur seal pups from Amsterdam Island, southern Indian Ocean. It used mark–recapture data from 7 consecutive years of different environmental conditions.

The cohort return rate varied from 45% to 74% of weaned pups, depending on the year of weaning. In each cohort, 96% of weaned pups returned between 3 and 6 years of age, and none of the factors examined seemed to influence this timing pattern. The probability of survival to this first return was negatively related to sea‐surface temperature anomalies (SSTa) of the 6 months following the weaning process. It increased with pup preweaning growth rate and differed between the sexes. Females’ survival rate was significantly higher than males’, except during years of extreme SSTa, where no difference was detected.

The juvenile state represented young individuals after their first return on their native island. Annual juvenile tag loss rate was constant at 0·217 (SE = 0·027), whereas temporary emigration rate varied over cohorts and was higher in males 0·423 (SE = 0·035) than in females 0·170 (SE = 0·012). This dispersion pattern may be prolonged in some cases, as the yearly immigration probability was constant at 0·290 (SE = 0·065).

Taking into account tag loss and temporary emigration, the estimated yearly survival probability of juveniles was 0·964 (SE = 0·022). This value was unrelated to any tested oceanographic or individual parameter including sex.

Results support the hypothesis that early development traits affect short‐term post‐weaning survival. However, no long‐term effect of maternal postnatal investment was detected after the first return to the native island. Results also indicate that the effect of early development traits on survival interacts with environmental conditions encountered shortly after independence of individuals.
Studies on the influence of power ultrasound on dye penetration in leather dyeing using photomicrographic analysis
Authors: SIVAKUMAR V. , SWAMINATHAN G. , RAO P. G.
Published: November 2005

The use of power ultrasound in enhancing diffusion rate in various chemical as well as physical processes is gaining in importance. The influence of power ultrasound in the leather dyeing process on enhancing the penetration of dye through the leather matrix was studied. The penetration of dye through a leather cross‐section for a given time in the presence and absence of an ultrasonic field (33 kHz, 150 W) was studied by photomicrographic analysis using a stereomicroscope. Different types of black dyes, such as Acid black 1, Metal complex black 194 and Direct black 155, were used for dyeing leather in the present study. Photomicrographic analysis of a cross‐section of dyed leather indicated better penetration of dyes through the leather matrix with the use of ultrasound than without it. Therefore, the results indicate that ultrasound helps to improve the diffusion of dye and to reduce diffusional resistance in the leather dyeing process.