bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing ICT‐based learning support and assessment system for dental education
Authors: Ruotoistenmaki J. , Autti H. , Peltola J. , Murtomaa H.
Published: November 2004

A dental degree programme is a complex combination not only just to acquire knowledge and skills but also to develop interpersonal skills. It is a challenge for both students and staff to conceptualise studies in larger entities and to emphasise learning as a process.

This project's general aim is to support student's development to become a self‐guided critical expert. This goal may be achieved by developing creative and inspiring learning and assessment atmosphere for basic, specialist and continuous education. The specific aim is to create a personal e‐portfolio program to facilitate utilisation of ICT based interaction and information, e.g. to document text, pictures, film and sound. The program is part of the assessment plan using e‐portfolio both summatively and formatively. Intra‐ and Internet are utilised to build a common data bank also to secure teaching continuity.

The project plan was awarded the first prize in the ICT‐for‐teaching competition at the University of Helsinki. The work is done in co‐operation by university and a private company. Project's pilot phase started on spring 2002 involving the first and third year students and their teachers. It continues for the fall term 2002 with two additional student groups. Participants have completed a questionnaire on their pre‐project ICT skills and attitudes. Training has been planned and carried out accordingly. The students are given the opportunity to produce a variety of personal versions and their copies for later use.

We conclude that it is very important to widen learning assessment methods to support students' continuous development beyond undergraduate programme and to learn to benefit from ICT. E‐portfolio used in this project is a digital platform for all these purposes. We are looking forward to collecting more data from our own institute and to working in close international co‐operation.
Biomolecular sciences in the dental curriculum – broadening the base to increase the relevance
Authors: Beeley J. A.
Published: November 2004

Although the increasing importance of biochemistry and allied subjects in the dental curriculum in the post‐genomic era is well recognised, there is considerable difficulty in motivating students and convincing them of the need for this. Students simply want to get on with dentistry (DentEd Report, 2001).

In a revised integrated interdisciplinary first year Biomolecular Science course introduced in Glasgow last session, the subjects covered now include crystals and restorations, cells and molecules, biophysical chemistry and radiation, carbohydrates, fats and proteins, cell metabolism, molecular biology, microbial biochemistry, antimicrobial agents, immunochemistry, nutrition, cell signalling, biochemistry of human tissues and clinical biochemistry. This broad approach enables this course to increasingly underpin much of the later curriculum including oral biology, oral pathology, materials science, restorative dentistry, oral medicine and public health as well as demonstrating to the students the relevance to dentistry.

Although this approach is quite well received, limitations include staff with the appropriate interests and expertise as well as relevant course texts. Further integration with clinical subjects is also required.

The developments which face dentists in the 21st century arising from the human genome project will be on a scale similar to those arising from the advent of IT. This approach may go some way to better equipping them for this.
Basic biology integration – the malmo model
Authors: Davies J. R. , Warfvinge G.
Published: November 2004

Knowledge of basic biological concepts is an essential ingredient for the development of a profound understanding of clinical phenomena and situations. In Malmo, knowledge within basic biology is gained in a clinical context and learning is thus motivated by the need for a scientific basis upon which to build the preventive measures, diagnoses and treatments carried out in the clinic.

As basic biology is spread throughout the curriculum in parallel with patient care, traditional subject categories are broken down and, for instance, cell biology is spread throughout the 5 years of study. However, in order to create a basis for continuous learning, many of the basic biological concepts are introduced early in the curriculum while their application to more complex situations is the focus of learning at later stages. For example, mechanisms of cell growth and division are introduced during the first and second semesters whereas tumour biology, a complex situation that requires an understanding of these phenomena, is studied during the ninth semester.

We conclude that the integration of basic biology and clinical dentistry combined with a problem‐based approach to learning gives the students opportunities to use and adapt their knowledge to common odontological problems and situations. This approach stimulates a deeper understanding of basic biological concepts as well as a willingness to apply such knowledge in the clinic. In a broader perspective, we propose that students are well prepared for their future role in the development of new strategies to promote oral health.
A test for the evaluation of manual dexterity
Authors: Giuliani M. , Clemente L. , Boari A. , Querqui A. , Lajolo C. , Viotti R. , Miani C. M.
Published: November 2004

In the last years, the use of tests with predictive value for scholastic progress has become widespread. While there is an aptitude test already in use for admission to our Dental School, we have also been conducting, without consequence to their admission, an investigation into the manual dexterity of candidate students. The aim of this test is to investigate basic manual dexterity, not ability following exercise. As previous, no such specific test had been formulated; the choice of test criteria we made was new. The tests investigated over five consecutive Academic years the ability to discern characteristics of a surface, to distinguish between different types of consistency, hand–eye co‐ordination, the graphic activities, laterality and muscular strength. A re‐test for some years was conducted afterwards. The results provided an overall evaluation: insufficient; sufficient; good; very good; excellent. Students who came from non‐technical high schools showed a good comprehension of questions put to them, use of strategy, description of procedures; and final checking but a certain clumsiness in the hand–eye co‐ordination test and a tendency to use one hand only. Students coming from technical high schools showed a less immediate grasp of questions put to them, sometimes requiring their repetition, disorganised behaviour in blind‐fold tests, insufficient use of strategies and little checking but notable ability in hand–eye co‐ordination tests and dextrous simultaneous use of both hands. These results were then correlated with the result of the aptitude test.

In conclusion, a notable correspondence between student selection based on the aptitude test and the experimental manual dexterity test was verified. This correspondence outlines that manual dexterity is not only a ‘manual’ but a ‘mental’ ability.
Development and evaluation of a cd‐rom to support student learning in dentist–patient communication
Authors: Newton J. T. , Reynolds P. A. , Thorogood N. , Harper J. , Cox M. J.
Published: November 2004

The interaction between dentist and patient is central to the provision of effective healthcare. A multidisciplinary team containing expertise in the social and behavioural sciences, medicine, dentistry, education and information technology was formed to design a CD‐ROM to support more traditional teaching and learning in this area. The final version of the program consists of a ‘virtual’ patient from whom students are asked to take a medical history. The ‘patient’ interacts with the student and responds to the style of their questioning by changes in anxiety, or degree of annoyance. To date, the CD‐ROM has been evaluated in two stages. The first stage was a predictive formative evaluation by the research/development team, and the second stage was a formative evaluation by 144 dental students of the first full prototype. A third stage, to be conducted next year, will involve measuring the longer term impact of the CD‐ROM through the assessment of students' abilities to communicate with patients. The evaluation had two components: students made rates of how useful and easy to use they found the program, and students' attitudes towards interacting with patients were evaluated adopting constructs from the theory of Planned Behaviour. Students were positive about the use of the CD‐ROM, though they requested some changes in the functionality of the program. Compared to a sample of students who had not used the CD‐ROM, the students who used the CD‐ROM felt more positive about communicating with their patients, at the end of the course, and expressed stronger intentions to communicate well with patients.

We conclude that the CD‐ROM we have developed in a useful adjunct to learning in dentist–patient communication.
Clinical and hematological features of β+‐thalassemia (IVS‐1 nt 5, G‐C mutation) in Thai patients
Authors: Laosombat Vichai , Wongchanchailert Malai , Sattayasevana Benjamas , Wiriyasateinkul Aranya , Fucharoen Supan
Published: November 2004

Abstract: Seventy‐eight patients with IVS‐1 nt 5, G‐C, which is the common mutation of β+‐thalassemia found in the southern part of Thailand, were studied to determine whether it is possible to predict phenotypic severity from genetic factors. The clinical phenotype of homozygotes for IVS‐1 nt 5, G‐C and compound heterozygotes for IVS‐1 nt 5, G‐C and β°‐ or β+‐thalassemia were variable and could not be accurately predicted. The associations between concomittant α‐thalassemia or Hb CS or the presence of XmnI‐Gγ polymorphism and a mild clinical phenotype are not apparent, indicating the involvement of other ameliorating determinants or genetic modifications.
Successful treatment of invasive mould infection affecting lung and brain in an adult suffering from acute leukaemia
Authors: Buxhofer Veronika , Ruckser Reinhard , Kier Peter , Habertheuer Karl‐Heinz , Tatzreiter Georg , Zelenka Peter , Dorner Stefan , Sebesta Christian , Knosp Engelbert , Hruby Walter , Hinterberger Wolfgang
Published: November 2004

Abstract: We describe in detail a 67‐yr‐old woman who was treated with a cytostatic combination chemotherapy for newly diagnosed common‐acute lymphoblastic leukaemia. At the end of induction therapy, the patient acquired invasive mould infection affecting lung and brain. The patient entered complete remission of her leukaemia. Treatment with liposomal amphotericin B was initiated along with surgical excision of the fungal brain abscess. Intrathecal instillation of amphotericin B deoxycholate was started using an Ommaya reservoir because of an anatomical connection between the postoperative cavity and the ventricle. Full dose cytostatic chemotherapy was continued with little delay. A computerised tomography scan of the chest performed 2 months later revealed no fungal abscesses. Magnetic resonance imaging of the brain did not reveal any fungal manifestation. During maintenance therapy/week 69, the patient relapsed from leukaemia. High doses of intravenous liposomal amphotericin B were administered prophylactically. The patient's leukaemia proved refractory to reinduction chemotherapy and the patient died from pneumonia 8 wk later. Post mortem microbiological investigation and histopathological examination of lung and brain tissue did not reveal any macroscopical or microscopical fungal manifestations. This case underlines the feasibility and successful application of combined antileukaemic, antifungal and surgical therapy in a patient with acute leukaemia.
Is there any significance for intracellular crystals in plasma cells from patients with monoclonal gammopathies?
Authors: Gardais J. , Geneviève F. , Foussard C. , Delisle V. , Zandecki M.
Published: November 2004

Abstract: Several plasma cells morphological changes have been described in monoclonal gammopathies, including intracytoplasmic crystals. We report one case of indolent κ‐chain multiple myeloma with renal insufficiency, featuring plasma cells with Auer‐rod‐like intracytoplasmic inclusions. The relationship between such aberrations and those found in multiple‐myeloma‐associated adult Fanconi syndrome is discussed. The significance of intracellular storage and crystallisation of immunoglobulin within plasma cells remains partially unknown.
Acute basophilic leukemia
Authors: Giagounidis A. A. N. , Hildebrandt B. , Heinsch M. , Germing U. , Aivado M. , Aul C.
Published: November 2004

Abstract: Acute basophilic leukemia has recently been included into a revised classification of acute leukemias proposed by the WHO panel. Due to the rarity of the disease, consistent diagnostic criteria are lacking. We report on two cases of acute basophilic leukemia that occurred in our department during the last 10 yr. We focus on their clinical, morphological and cytogenetic presentation. Both patients were >60 yr of age, and presented in good clinical condition with alterations to their full blood count. None had cutaneous symptoms such as erythema or urticaria. Cytogenetic analyses in the first patient showed a normal karyotype, while the second displayed a translocation t(2;6); (q23?4;p22?3), as well as a del (12)(p11). Earlier observations have linked bone marrow basophilia either to a deletion of the short arm of chromosome 12 (p11–13), to translocations involving the long arm of chomosome 6 at 6q23 or to the translocation t(6,9); (p23;q34). However, other translocations involving chromosome 6p23 have not been described before. Treatment of our patients consisted of supportive treatment in the one with normal karyotype and aggressive chemotherapy in the other patient. Both patients died within one year after diagnosis due to progressive or recurrent leukemia.
Erythropoietin mediates terminal granulocytic differentiation of committed myeloid cells with ectopic erythropoietin receptor expression
Authors: Arcasoy Murat O. , Maun Noel A. , Perez Lia , Forget Bernard G. , Berliner Nancy
Published: November 2004

Abstract: Objectives: The precise role of hematopoietic cytokine/cytokine receptor interactions in lineage‐restricted hematopoietic differentiation giving rise to mature blood cells of diverse function is incompletely defined. To study lineage‐specific effects of cytokines during terminal hematopoietic differentiation, we examined the ability of erythropoietin (Epo) to mediate terminal granulocytic differentiation and induction of myeloid gene expression in committed myeloid cells, engineered to ectopically express Epo receptor (EpoR). Methods: A cell culture model for granulocyte‐macrophage colony stimulating factor (GM‐CSF)‐mediated granulocytic differentiation was used. EpoR was introduced by retrovirus‐mediated gene transfer into multipotential, hematopoietic murine cell line EML, from which GM‐CSF‐responsive, promyelocytic EPRO cells were generated. In EPRO cells ectopically expressing EpoR, we examined the ability of Epo to mediate granulocytic differentiation and determined whether Epo‐mediated neutrophil differentiation is associated with a pattern of myeloid gene expression comparable to that induced by GM‐CSF. Results: Studies of EpoR function in myeloid EPRO cells revealed that Epo/EpoR interaction can mediate terminal granulocytic differentiation of committed myeloid cells. In EPRO cells expressing EpoR, Epo‐mediated neutrophil differentiation was associated with surface CD11b/CD18 (Mac‐1) expression and induction of mRNA expression of specific myeloid genes including lactoferrin, gelatinase and C/EBPε, in a manner similar to GM‐CSF‐mediated differentiation. Conclusions: These results indicate that Epo can deliver differentiative signals along a non‐erythroid lineage, providing evidence for interchangeable cytokine receptor signals that mediate terminal differentiation of committed myeloid cells.
Hyaluronic acid and endothelial damage due to paracetamol‐induced hepatotoxicity
Authors: Williams Anna M. , Langley Peter G. , Osei‐Hwediah Johnson , Wendon Julia A. , Hughes Robin D.
Published: November 2004

Abstract: Background: Damage to endothelial cells may be an important factor in the complications of acute liver failure, resulting in multi‐organ failure. The aim of this study was to assess endothelial cell function in patients with severe hepatotoxicity due to paracetamol ingestion.

Patients and methods: Fifty‐eight patients with paracetamol‐induced hepatotoxicity were studied for up to 7 days. Serum hyaluronic acid (HA), as a marker of hepatic sinusoidal endothelial cell function, was determined using an enzyme‐linked binding assay. Plasma von Willebrand Factor, thrombomodulin and interleukin‐8 were also determined using ELISA.

Results: Serum HA on admission was significantly increased (median 6777 ng/ml, range 24–50 967 ng/ml) as compared to normal controls (n = 10, median 21 ng/ml, range 0–50 ng/ml; P < 0.001). In non‐survivors (n = 21) HA levels peaked on day 2 after admission (P = 0.044), and then decreased. In the survivors (n = 37) the levels of HA did not increase further. Plasma von Willebrand Factor, plasma thrombomodulin and serum interleukin‐8 were significantly increased in the patients as compared to the normal controls (P < 0.001). Serum interleukin‐8 was significantly higher in non‐survivors in the first 2 days.

Conclusions: Endothelial function is abnormal in paracetamol‐induced hepatotoxicity. Damage to hepatic sinusoidal endothelial cells assessed by serum HA was greater in non‐survivors than survivors.
Histological features associated with relapse after corticosteroid withdrawal in type 1 autoimmune hepatitis
Authors: Czaja Albert J. , Carpenter Herschel A.
Published: November 2004

Abstract: Relapse of type 1 autoimmune hepatitis after drug withdrawal may relate to incomplete histological improvement during corticosteroid therapy and/or persistence of pathogenic mechanisms.

Aim: Determine the histological features prior to drug withdrawal that are associated with relapse in patients satisfying pre‐established clinical, laboratory, and histological criteria for remission and relapsing after corticosteroid withdrawal.

Methods: One hundred liver tissue samples obtained immediately prior to corticosteroid withdrawal from 88 patients who had previously satisfied criteria for histological remission were reviewed retrospectively.

Results: Histological findings in the patients who relapsed were similar to those in the patients who sustained remission in regard to histological activity index (1.7 ± 0.1 versus 1.6 ± 0.2, P = 0.6), fibrosis score (2.6 ± 0.3 versus 2.3 ± 0.4, P = 0.5), and frequencies of interface hepatitis (36% versus 20%, P = 0.2), cirrhosis (21% versus 17%, P = 0.8), and normal or near normal tissue (9% versus 7%, P > 0.9). Only the presence of portal plasma cells was associated with relapse (31% versus 7%, P = 0.01). The positive predictability of portal plasma cell infiltration for relapse was 92%, but its sensitivity was only 31%.

Conclusions: Portal plasma cell infiltration is predictive of relapse after drug withdrawal in tissue specimens already satisfying criteria for remission. Portal plasma cell infiltration may be indicative of an active antibody‐dependent pathogenic mechanism. Its low sensitivity for relapse indicates the need for other complementary predictors of outcome.
Costs and benefits of ant attendance to the drepanosiphid aphid Tuberculatus quercicola
Authors: Yao Izumi , Shibao Harunobu , Akimoto Shin‐ichi
Published: November 2004

The defensive effects of ants against aphid predators have been well documented in the mutualistic relationship of aphids and their attending ants. However, it is not clear whether ant attendance has any direct effect on the aphids’ growth and reproduction. Through field experiments, this study evaluates the benefits and, in particular, the costs of ant attendance to aphid colonies, focusing on the drepanosiphid aphid Tuberculatus quercicola which is associated with the Daimyo
oak, Quercus dentata, and which is always attended by the red wood
ant Formica yessensis. Ant attendance was clearly beneficial to the aphid; the exclusion of ants led to a significant increase in the extinction rate of aphid colonies. However, MANOVA and randomized block ANOVA indicated that in colonies continuously attended by ants, aphids had significantly smaller body size and produced a smaller number of embryos than in colonies isolated from ants when they were reared under homogeneous host conditions free from natural enemies. Thus, ant attendance had a negative influence on the growth and reproduction of the aphids, even though it contributed to the greater longevity of the aphid colonies. We hypothesize that ant‐attended aphids are under intense selective pressures that act against aphid clones which fail to attract many ants, so that aphids have developed an adaptive mechanism to allocate a larger fraction of resources to the honeydew when they are requested to do so by the ants in order to ensure the ants’ consistent visitation.
Environmental determinants of Phragmites australis expansion in a New Jersey salt marsh: an experimental approach
Authors: Bart David , Hartman Jean Marie
Published: November 2004

Interdependence among disturbance events, ecosystem properties, and biological invasions often make causal relationships difficult to discern. For example, Phragmites australis invasion in
mid‐Atlantic salt marshes is often associated with disturbances that
create well‐drained features as well as with low sulfide concentrations,
but explanations of these associations have been elusive. We tested
experimentally: 1) that disturbances increasing wetland drainage
facilitate Phragmites invasion by altering sulfide concentrations
and salinity; 2) that translocation allows plants to spread beyond
drainage areas; and 3) that plants can then lower edaphic stress through
pressure ventilation of the rhizosphere and promote further expansion. At
the invasion front, treatments of 1) severing rhizomes to halt
translocation and 2) combined severing with clipping dead culms to limit
ventilation of the rhizosphere killed most culms, but did not affect pore
water chemistry. In already invaded areas, severing and clipping reduced
culm height and panicle production, severing alone and in combination
with clipping also raised sulfide and ammonium concentrations in the root
zone. There were no treatment effects on plant performance or pore water
chemistry along mosquito ditches, where sulfide concentrations were
negligible. Small‐scale hydrological alterations such as ditches appear
to provide suitable sites for the establishment of Phragmites because soils are well‐drained and are low in free sulfides. Subsequent expansion into more hostile areas occurs through translocation, with well‐drained areas acting as sources for essential substances. Once established, the plant increases rhizosphere oxygenation and lowers sulfide concentrations.
How leaf domatia and induced plant resistance affect herbivores, natural enemies and plant performance
Authors: Agrawal Anurag A. , Karban Richard , Colfer Ramana G.
Published: November 2004

Predators and plant resistance may act together to control herbivorous arthropod populations or antagonistically, which would reduce the control of pest populations. In a field experiment we enhanced predation by adding simulated leaf domatia to plants. Leaf domatia are small structures that often harbor predaceous arthropods that are potentially beneficial to the plant. We also manipulated host plant quality by inducing resistance with controlled, early season exposure of seedlings to spider mite herbivory.  Our manipulations had profound consequences for the natural community of arthropods that inhabited the plants. Leaf domatia had a direct positive effect on abundances of two species of bugs and one species of thrips, all of which are largely predators of herbivores. On leaves with domatia, each of the predators was found inside the domatia two to three times more often than outside the domatia. Eggs of predaceous bugs inside leaf domatia were protected from parasitism compared to eggs outside the domatia. The positive effects of leaf domatia on predator abundances were associated with reduced populations of herbivorous spider mites, aphids, and whiteflies. Plants with experimental leaf domatia showed significantly enhanced reproductive performance.  Induced resistance also affected the community of arthropods. Of the abundant predators, all of which also fed on the plant, only minute pirate bugs were negatively affected by induced resistance. Populations of herbivorous spider mites and whiteflies were directly and negatively affected by induction. In contrast, aphid populations were higher on plants with induced resistance compared to uninduced plants. Effects of induced resistance and domatia were additive for each of the predators and for aphids. However, spider mite and whitefly populations were not suppressed further by employing both induced resistance and domatia compared to each strategy alone. Our manipulations suggest that plant defense strategies can have positive effects on some species and negative effects on others. Negative effects of “resistance traits” on predators and positive effects on some herbivores may reduce the benefits of constitutive expression of resistance traits and may favor inducible defense strategies. Multiple plant strategies such as inducible resistance and morphological traits that aid in the recruitment of predators of herbivores may act together to maximize plant defenses, although they may also be redundant and not act additively.
The best in all possible worlds? A quantitative genetic study of geographic variation in the meadow vole, Microtus pennsylvanicus
Authors: Hansen Thomas F. , Boonstra Rudy
Published: November 2004

The meadow vole, Microtus pennsylvanicus, is the most widely
distributed Microtus species in North America. Across its range,
it shows marked demographic differences, experiences a large range of
climatic conditions, and varies considerably in body size and
life‐history characteristics. To study the genetic basis of the
geographic variation in size and life history of this species, we
subjected three populations, one from central Canada and two from eastern
Canada, to quantitative genetic analysis in the lab. We studied the
variance and covariance of several size and growth variables as well as
age and size at maturity by means of population crosses, full‐sib
analysis, and parent‐offspring regressions. We found that the phenotypic
differences among these populations are almost entirely due to
environmental effects. However, within populations, additive genetic and
maternal effects explain most of the variation. We discuss possible
explanations for the lack of genetic differences among the populations
and speculate that a similar reaction norm is maintained in all
populations through heterogeneity in the temporal or spatial environment
that the populations experience. The heterogeneity may be mediated
through population density fluctuations, climatic variation, or variation
in site productivity. Thus, we hypothesize that M. pennsylvanicus has evolved to be the best in all possible worlds rather than in one actual world. This study highlights the crucial importance of maternal and environmental effects on the size, growth, and life history of small rodents.
Modelling species richness and diversity in grassland communities of the Central Caucasus
Authors: Kikvidze Zaal
Published: November 2004

In this study I used small squares (4 cm×4 cm) as a sampling technique within plots (128 cm×128 cm) of different elevation, aspect and slope angle in grassland communities (20 plots examined). Then I used a rectangular hyperbole equation (the Michaelis‐Menten model) to describe species richness and the Inverse of Simpson Concentration (ISC) as functions of sample size. I checked robustness and precision of the model both by interpolation and extrapolation. Interpolation was similarly good in both cases, while extrapolation produced reliable predictions of ISC but underestimated species richness. Dominance analysis indicated that the underestimation of richness depends on the proportion of bottom species, and that the predicted values of richness roughly coincide with the numbers of dominant species found in plots. Therefore, the model may be used to assess number of dominant species when precision is less important than saving time during a survey. However, the rectangular hyperbole equation appears to be precise and robust in the prediction of ISC, at least in grassland communities. This property may also be employed for extrapolation of diversity indices with a limited sampling effort.
The influence of sediment type on the aggregative response of oystercatchers, Haematopus ostralegus, searching for cockles, Cerastoderma edule
Authors: Johnstone Ian , Norris Ken
Published: November 2004

Models that describe the dispersion patterns of predators between a series of patches that vary in prey density frequently assume that predators, in the absence of interference, will aggregate in patches with the highest prey density, at any point in time. This assumption has important implications for patterns of prey mortality, and the extent to which prey mortality is density dependent. In natural predator‐prey systems, it is likely that environmental factors interact with spatial variation in prey density to influence the aggregative response of predators. We show data consistent with this idea on a population of overwintering oystercatchers foraging on cockles. There was no evidence that birds aggregated in patches with the highest biomass density of cockles. The biomass density of cockles was highest in muddy patches at the start of winter, and birds aggregated in patches that switched from being muddy at the start of winter to being sandy at some point during the winter. We argue that sediment type influences foraging costs experienced by the birds, so birds avoid feeding in muddy patches unless the fine sediment is removed from a patch, as happens during winter storms. When this happens a high biomass density of cockles suddenly becomes available and the birds aggregate in such patches. The rate of biomass loss was greatest in patches used intensively by birds for feeding, suggesting that the birds’ aggregative response influences cockle mortality. We discuss the implications of our results for ideal free models.
Alternative strategies by thermophilic ants to cope with extreme heat: individual versus colony level traits
Authors: Cerdá Xim , Retana Javier
Published: November 2004

Cataglyphis is a fairly homogeneous ant genus which is
widespread over the arid regions of the Old World. All Cataglyphis
species are thermal specialists which are adapted to extreme environments
where they forage at nearly lethal temperatures. This study focusses on
two Cataglyphis species which differ considerably in their
physical caste systems. These species have developed two alternative
mechanisms facing extreme heat. In C. velox, foraging at high
surface temperatures is clearly dependent on size: large C. velox
workers forage at midday and are able to withstand higher temperatures
than small workers. On the other hand, C. rosenhaueri has not
developed great physical specialization, but the workers of this species
have achieved physiological (such as low cuticular transpiration and
metabolic rate), and behavioural adaptations (such as raising their
abdomen to protect the vital organs contained in it from high
temperatures) to tolerate thermal stress. The result is that small C.
rosenhaueri workers may withstand extreme heat conditions in a
similar way to large C. velox workers, and much better than small
C. velox workers. The different mechanisms used by these two species to withstand extreme heat could reflect fundamental patterns of independent evolution. In some situations, selection may act to promote a relatively narrow size range of adult workers, all of them able to withstand thermal extremes, while in others it may act by producing different worker sizes with different tolerance to environmental conditions.
Analysing the Moran effect and dispersal: their significance and interaction in synchronous population dynamics
Authors: Ripa Jörgen
Published: November 2004

Population synchrony over various geographical scales is known from a large number of taxa. Three main hypotheses have been put forward as explanations to this phenomenon. First, correlated environmental disturbances (so called Moran effect). Moran showed that at least for linear models, the population synchrony would exactly match that of the corresponding environment. Second, the migration, or dispersal, of individuals is liable to cause population synchrony. Third, nomadic predators have been proposed as a synchronising mechanism. In this paper, I analyse the first two explanations by linearizing a general population model with spatial structure. From this linear approximation I derive an expression for the population synchrony. The major results are: 1) Population synchrony can vary significantly depending on the timing of the population census. 2) The environmental correlation is always important. It sets the ‘base level’ of synchrony. 3) Dispersal is only an effective synchronising mechanism when the local dynamics are at least close to unstable. 4) These results are valid even in a model with delayed density dependence – with possibly cyclic dynamics. Time lag structure has little effect on synchrony.  Some of the predictions presented here are supported by data from the literature.
Mixed significance of plant vigor: two species of galling Pontania in a hybridizing willow complex
Authors: Kokkonen Katri
Published: November 2004

Distributions of leaf galls and offspring performance of two Pontania sawfly species were explored in individual willows of the
subarctic Salix caprea–starkeana hybrid complex. The
more common sawfly, an undescribed species near the dolichura
group (P1), had the highest gall numbers in trees with long shoots both
in S. caprea and hybrids. While numbers were high on vigorously
growing hybrids, offspring of P1 were aborted significantly more often on
hybrids than on pure hosts. Further, non‐aborted galls were smaller on
hybrids. Fast shoot growth may be important for P1 sawflies, because
females oviposit early in summer and larvae develop rapidly compared with
the other species, Pontania pedunculi (P2). Distributions of P2 galls were related to tree height and not to shoot length in both parental and hybrid groups of willows. Like P1, also P2 offspring were frequently aborted on hybrids, but not significantly more often than on pure hosts, and P2 galls were equally large among the host groups. Survival of both species was related to abortion rates, while larvae were parasitized equally in all host groups. This study demonstrates that the significance of plant vigor may vary even for closely related galling sawflies exploiting the same hosts, or for the same species on different host plants. Vigorous growth may mislead gallers to oviposit on suboptimal plants.
Growth and survival effects on maturation pattern in populations of grayling with recent common ancestors
Authors: Haugen Thrond O.
Published: November 2004

Mortality and growth rates were shown to influence maturation patterns in five populations of grayling (Thymallus thymallus) in central
Norway. The populations share recent common ancestors as they derive from
introductions performed in 1910, and they inhabit lakes with different
environmental conditions (i.e. length of growth season, lake area and
fishing pressure). Mortality rate (range of Z‐values:
0.36–0.77) and growth pattern varied strongly among the
populations. Mortality rates were negatively associated with population
mean age at maturity (rsp=−0.90), supporting life‐history theory which predicts early maturation to be favoured under conditions with high adult mortalities. Maturation reaction norms differed significantly among the populations. Individuals from one population showed no maturation plasticity (all individuals matured at age three), whereas rapid growers were found to mature earlier than slow growers in the remaining four populations. Life‐history theory is again supported as it predicts rapid growers to mature early due to high age‐specific fecundity and short generation times. Given low mortality risks, slow growers are predicted to delay maturation in order to gain high first‐time fecundity. In high‐mortality systems all individuals are predicted to mature early. This theory is supported by the present data as populationwise maturation plasticity increased with decreasing mortality rates. In the population with no maturation plasticity the corresponding high mortality rates were probably due to high fishing pressures.
The pattern and range of movement of a checkered beetle predator relative to its bark beetle prey
Authors: Cronin James T. , Reeve John D. , Wilkens Richard , Turchin Peter
Published: November 2004

Theoretical studies of predator‐prey population dynamics have increasingly centered on the role of space and the movement of organisms. Yet, empirical studies have been slow to follow suit. Herein, we quantified the long‐range movement of a checkered beetle, Thanasimus
dubius, which is an important predator of a pernicious forest pest,
the southern pine beetle, Dendroctonus frontalis. Adult checkered beetles were marked and released at five sites and subsequently recaptured at traps baited with pine and pine beetle semiochemicals and located at distances up to 2 km away from the release point. While the pattern of recaptures‐with‐distance at each site provided a modest fit to a simple random‐diffusion model, there was a consistent discrepancy between observed and expected recaptures: a higher than expected proportion of beetles were recaptured at the more distant traps. To account for this deviation, we developed a model of diffusion that allowed for simple heterogeneity in the population of marked beetles; i.e., a slow and fast moving form of the checkered beetle. This model provided a significantly better fit to the data and formed the basis for our estimates of intra‐forest movement. We estimated that on average, one half of the checkered beetles dispersed at least 1.25 km, one third dispersed>2 km, and 5% dispersed>5 km. The source of the heterogeneous dispersal rates were partially due to differences in beetle size: smaller beetles (for both males and females) were more likely to be recaptured away from the release site than larger beetles. The southern pine beetle (prey for the checkered beetle) exhibited no significant heterogeneity in dispersal ability and provided a very good fit to the simple diffusion model. The only difference in dispersal between these two species was that checkered beetles were undergoing greater long‐distance dispersal than the pine beetles (the radius containing 95% of the dispersing individuals was 5.1 km for the checkered beetle and 2.3 km for the pine beetle). Data on the movement of these two species is used to evaluate a general model of spatial pattern formation in a homogeneous environment, and the potential of the checkered beetle as a biological control agent for the southern pine beetle.
Effects of female kin groups on reproduction and demography in the gray‐tailed vole, Microtus canicaudus
Authors: Dalton Christine L.
Published: November 2004

I conducted an experiment with gray‐tailed voles, Microtus
canicaudus, to test the hypothesis proposed by Charnov and Finerty that populations of voles comprised of female kin groups would grow more rapidly and reach higher densities more quickly than populations in which female kin groups were disrupted. The experiment was conducted in 0.2‐ha semi‐natural enclosures planted with mixed grasses. In four enclosures, females were unmanipulated (control) and in four enclosures all newly caught females were removed from their natal enclosures and replaced with females of comparable age from another enclosure, such that juvenile females did not settle near their siblings or parents (treatment). I found no significant differences in survival, reproduction, juvenile recruitment, population growth rates, or population size between control and treatment populations. The only difference was the time to sexual maturation for young females, which was 3.1 weeks for control enclosures compared with 4.2 weeks for treatment enclosures. I could not measure reproductive success for individual females, but my results did not support the hypothesis that the presence or absence of kin groups resulted in any biologically meaningful population‐level effects. Female voles that have nesting territories adjacent to relatives may accrue some individual benefits, but these benefits are unlikely to contribute to population regulation in gray‐tailed voles.
Allocation of resources within mountain birch canopy after simulated winter browsing
Authors: Lehtilä Kari , Haukioja Erkki , Kaitaniemi Pekka , Laine Kari A.
Published: November 2004

As a response to browsing, birches are known to produce fewer but larger, more nutritious leaves, with enhanced palatability for herbivores. We simulated winter browsing in ramets of mountain birch (Betula pubescens ssp. czerepanovii) to find out whether it decreases subsequent foliage biomass and alters the number and type of shoots. After removal of a considerable proportion of buds (up to 35%) in late winter, the birches were able to compensate for the lost leaf biomass in the following summer; there were no differences in total leaf biomass between winter‐clipped and control ramets. This indicates that foliage growth was limited by the total amount of stored resources, not by the number of buds. Depending on the position of the buds removed, different mechanisms were responsible for the compensation. After removal of apical buds, the number of leaves decreased significantly but leaves were larger than in control ramets. Removal of the same mass of basal buds – containing similar amount of carbohydrates and proteins as in the treatment removing apical buds – activated dormant buds, especially in apical locations, so that leaf number was similar as in the controls; consequently, size of individual leaves increased only slightly. Thus, while the total leaf biomass in a tree seems to be limited by resources from source organs, the distribution of resources among different canopy sections is controlled by their relative sink strengths. In terms of leaf biomass, apical parts are able to compensate for bud loss by increasing shoot number, basal parts only by increasing leaf size.
Intraclutch egg‐size variation in acanthosomatid bugs: adaptive allocation of maternal investment?
Authors: Kudo Shin‐ichi
Published: November 2004

If there are differences in predation risk among the offspring within a clutch, parents may allocate less resources to the offspring facing higher risk. I examined parental investment in terms of egg size within clutches in five species of stink bugs (Heteroptera, Acanthosomatidae). In subsocial Elasmucha and Sastragala species, the female guards her eggs and first‐instar nymphs against invertebrate predators by covering her clutch with her body. Large differences in survival from predation between offspring at the centre and offspring at the periphery of the clutch have been reported in such subsocial insects. I found that Elasmucha and Sastragala females laid significantly smaller eggs in the peripheral (and thus more vulnerable) part of the clutch. Phenotypic trade‐offs between egg size and clutch size were detected in these subsocial species. Egg size was positively correlated with hatched first‐instar nymph size: smaller nymphs hatched from smaller peripheral eggs. In asocial Elasmostethus humeralis, however, no significant difference in size was detected between the eggs at the centre of and those at the periphery of the clutch. Thus, in subsocial acanthosomatid bugs, females seem to allocate their resources according to the different predation risks faced by the offspring within the clutch.
Seasonal changes in female size and its relation to reproduction in the parasitoid Asobara tabida
Authors: Ellers Jacintha , Bax Minka , Van Alphen Jacques J. M.
Published: November 2004

The relation between female size and fitness was studied in female Asobara tabida throughout the field season. The size of A. tabida females varied considerably, with average size being smallest in the middle of the season. There was a positive correlation of realized fecundity with size, and the fitness advantage of larger females increased later in the season. A possible explanation for this can be found in the energy expenditure during the season. Regression analysis showed that fat use increases with size of the female, but also with temperature. Temperature was low early and late in the season, but high in the middle. We argue that the high temperatures may constrain fitness advantages of large females because of their increased metabolic needs. Variation in the form of the fitness function within the season may moderate directional selection for larger females.
Charles Lyell –“the father of geology”– as a forerunner of modern ecology
Authors: Wool David
Published: November 2004

In 1830, Charles Lyell published the first volume of his influential book, “The principles of geology”. Young Charles Darwin took the book on board the “Beagle” and, upon his return, acknowledged the contribution it made to his own research. Lyell did not believe in transmutation and evolution, and explained the differences in the fossil fauna between different geological formations by the accumulated environmental changes over a very long geological time. He describes ecological interactions of organisms with their biotic and abiotic environment in a language similar to current ecological concepts. Lyell may be seen as one of the forerunners of modern ecology.
Clonal dynamics and evolution of dormancy in the leafy hepatic Lophozia silvicola
Authors: Laaka‐Lindberg Sanna , Heino Mikko
Published: November 2004

Dead shoots of colonies of a leafy hepatic species, Lophozia silvicola, are replaced by shoots developing from asexual propagules, the gemmae. Observations of two populations of L. silvicola showed a strong decreasing seasonal trend in germinability of the gemmae. We suggest that the non‐germinating gemmae enter dormancy, and that the proportion of gemmae entering dormancy is season‐specific. We assume that there are two types of gemmae, dormant and non‐dormant and that only the dormant gemmae can survive during winter. Using a stochastic individual‐based cellular automaton model, we investigated whether selection on season‐specific dormancy fraction would lead to a decreasing proportion of germinating gemmae. Thus the germination schedule is the evolving trait in the model. Parameter estimates for the model were based on data collected from a population of L. silvicola in southern Finland over a three‐year study period. In the simulations, the germination schedule shaped by evolutionary change was similar to the observed pattern. Thus the modelling results give support to the dormancy hypothesis. The qualitative pattern of decreasing germinability towards the end of the growing season is robust. Quantitative predictions are influenced by changes in parameters; for example, if winter mortality of shoots increases relative to mortality during the growing season, production of an increased fraction of dormant gemmae is favoured, especially at the end of the season.