bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of magnetic field on the manganite-based bilayer junction
Authors: Sun J. R. , Xiong C. M. , Zhao T. Y. , Zhang S. Y. , Chen Y. F. , Shen B. G.
Published: February 2004

An oxide bilayer junction has been fabricated by growing a La0.32Pr0.35Ca0.33MnO3 film on 0.5 wt % Nb-doped SrTiO3 crystal, and its behavior under magnetic field is experimentally studied. It is found that external field greatly affected the rectifying property and the resistance of the junction, causing an extremely large magnetoresistance. The most striking observation of the present work is that the magnetoresistance of the junction can be either positive or negative, depending on temperature and applied current, and is asymmetric with respect to the direction of the bias current. These results reveal the great potential of the manganites in configuring artificial devices.
Are diel patterns of nectar production and anthesis associated with other floral traits in plants visited by potential bird and mammal pollinators?
Authors: Saffer V. M.
Published: February 2004

Plants pollinated predominantly by vertebrates are thought to have suites of floral traits (e.g.�colour, conspicuousness, odour) that favour either birds or mammals, with brightly coloured, conspicuous flowers associated with birds and drab, concealed flowers with non-flying mammals. This study examined two other floral traits, diel patterns of nectar production and pollen presentation (anthesis). It would be expected that these would be nocturnal in putatively mammal-pollinated plants and diurnal in bird-pollinated plants. In four Banksia and two Dryandra species, all known to be visited by honeyeater birds and small marsupials at one site in south-western Australia, there was no clear correspondence between visual cues and diel patterns of resource presentation. This lack of correlation between floral traits does not support the idea of specialised pollination syndromes, but rather is consistent with generalised pollination systems.
Potential impacts of fire and grazing in an endangered ecological community: plant composition and shrub and eucalypt regeneration in Cumberland Plain Woodland
Authors: Hill Sarah J. , French Kristine
Published: February 2004

Exclosure plots were used to determine the effect of fire and grazing on the structure of a grassy-woodland community. Eighteen months after fire and fence treatments were applied, the species richness, cover and composition of shrubs, trees, herbs and grasses were assessed and compared to pre-treatment censuses. Unburned plots had fewer shrub species and a lower abundance of shrubs, indicating the importance of fire in promoting regeneration of shrub species. Eucalypt species were more abundant and richer following the wildfire burn in summer, suggesting timing of fires is an important aspect in the establishment of the canopy species. Interactions between fire and grazing were found for the abundance of eucalypts (although weak) and resprouting eucalypts, suggesting a subtle interaction between fire and grazing shortly after fire. There was no effect of grazing and no interaction effect between fire and grazing on shrub species richness and abundance or tree species richness and seedling abundance.All plots showed a change in species composition despite treatment, and 46 species (32% of total richness) were recorded only in the final survey. The high rainfall during the 18-month study is likely to be an important factor in facilitating the establishment of species following all disturbances. This may have ameliorated the impact of grazing as abundant food was available throughout the woodland. The interaction between fire and grazing may be more important in structuring these grassy communities during periods of lower rainfall.
Micromorphological variability of leaf epidermis in Mesoamerican common bean (Phaseolus vulgaris, Leguminosae)
Authors: Stenglein Sebastian A. , Arambarri Ana M. , Vizgarra Oscar N. , Balatti Pedro A.
Published: February 2004

The purpose of this work was to make a detailed description of leaf epidermal characteristics among four Mesoamerican common bean (Phaseolus vulgaris L.) types, since they may play a role in plant defence against pathogens and/or drought. Therefore, we studied variability of epidermal cell number per mm2, stomatal size and number per mm2, stomatal index, and trichome density and dimensions on both the adaxial and abaxial epidermal surfaces. In all the common bean types studied, both surfaces of the leaves were devoid of wax crystalloids. Trichome density and distribution differed among the common bean types. Furthermore, the abaxial leaf surface always presented more trichomes than the adaxial surface. The leaves were amphistomatic, with the guard cells located in line with epidermal cells. Common bean leaves presented paracytic, anomocytic and anisocytic stomatal types. All common beans presented the adaxial epidermis of the leaves with a lower density of bigger stomates than on the abaxial epidermis.Our results demonstrate that micromorphological characteristics on both leaf surfaces are variable traits among common bean types.
Apospory in Paspalum thunbergii
Authors: Ma Guohua , Huang Xuelin , Zhao Nanxian , Xu Qiusheng
Published: February 2004

The cytology, development of aposporous embryo sac, pro-embryo and pseudogamy in Paspalum thunbergii Kunth ex Steud. was studied. P. thunbergii was found to be a tetraploid cytotype, with a chromosome number of 40. Meiosis of the pollen mother cells was irregular, pollen viability was low and multiporate pollens were often observed. Megasporogenesis began normally; however, the megaspore deteriorated at the developmental stage of tetrad, while one to five specific nucellar cells became active and began enlarging, and then developed into aposporous embryo sacs. The mature aposporous sacs usually had three nuclei characterised by one egg cell and two polar nuclei. The egg cell developed spontaneously to form pro-embryos prior to anthesis. When several aposporous sacs occurred in the same ovule, usually one sac near the micropyle was involved in pseudogamy, while the other sacs were not involved. Low frequency of twin-embryo seedlings was observed after seeds matured. Examination of three successive generations by paraffin-section and clearing methods revealed that no sexual sac was present. Therefore, the species P. thunbergii is considered to be an obligate apomict that reproduces by apospory.
Chloroplast DNA variation and inheritance in waxflowers (Myrtaceae)
Authors: Ma Xuanli , Considine John A. , Yan Guijun
Published: February 2004

A study of chloroplast DNA variation and inheritance in waxflowers (Myrtaceae) was undertaken as a basis for validating parentage in putative, juvenile hybrid plants and in naturally occurring hybrids. Polymerase chain reaction amplification of three chloroplast DNA regions, followed by restriction of the amplified products, was used to identify restriction fragment length polymorphisms (RFLP) in 18 Chamelaucium uncinatum and C.�megalopetalum genotypes. Five cpDNA haplotypes were observed within the two species studied. In C.�uncinatum, three site mutations and one length mutation were observed, corresponding to three cpDNA haplotypes; and in C. megalopetalum, two cpDNA haplotypes were observed.Chloroplast DNA (cpDNA) inheritance was studied in 17 intraspecific and 33 interspecific hybrids by using the cpDNA polymorphisms between the female and the male parents. Maternal cpDNA inheritance was observed in all cases, as in most angiosperms. These results support a 95.5% probability of maternal cpDNA inheritance in waxflowers at the 90% confidence level.The method has been used to identify maternal parents of naturally occurring hybrids in our waxflower breeding program. It may also be applied to the study of the evolution of natural populations and, in this study, indicates distinct lines of evolution for individual populations of the two species.
Long-term flowering synchrony of box-ironbark eucalypts
Authors: Keatley Marie R. , Hudson Irene L. , Fletcher Tim D.
Published: February 2004

Long-term (1940–1970) flowering synchrony of Eucalyptus leucoxylon ssp. pruinosa (F.Muell. ex Miq.) Boland, E. microcarpa (Maiden) Maiden, E. polyanthemos ssp. vestita L.A.S.Johnson & K.D.Hill and E. tricarpa (L.A.S.Johnson) L.A.S.Johnson & K.D.Hill was quantified at the tree level. The least synchronous grouping was E. polyanthemos and E. microcarpa (0.06), with flowering overlap occurring in only 5 of the 30 years. The species with the most synchronous flowering were E. leucoxylon and E. tricarpa (0.62): flowering overlapped in 24 of the 30 years. Synchrony in the 1996–1997 flowering season was found to be 'typical': overlap among all species pairs and groupings was within the range delineated by the long-term data (e.g. the synchrony of 0.53 for E. leucoxylon and E. polyanthemos was similar to its mean long-term overlap of 0.51). Individual species flowered synchronously, both within (0.82–0.92) and across sites (0.81– 0.93). Flowering did not occur in any of the monitored trees during 1997–1998. Long-term synchrony values assist in quantifying the likelihood of hybridisation between species, and provide a baseline which may assist in detecting recent or future changes.
Seed-bank dynamics of Eleocharis: can spatial and temporal variability explain habitat segregation?
Authors: Bell Dorothy M. , Clarke Peter J.
Published: February 2004

Four Eleocharis species exhibit habitat partitioning in both extant vegetation and in the soil seed bank of upland temporary wetlands on the Northern Tablelands of New South Wales. Explanations for this partitioning were sought in seed-bank dynamics at three shore levels in two wetlands. Habitat partitioning (zonation) was explained in part by seedling recruitment but not by either persistence of seeds in the soil or by dormancy patterns. All four species recruited at wetland edges but only the deepwater species, Eleocharis sphacelata, recruited in deeper water. Viability of buried seeds was consistently high and species had very low decay rates and half-lives greater than 50 years. Two types of dormancy patterns with burial were shown. Most seeds of Eleocharis sphacelata and E. pusilla were non-dormant after a 3-month burial, whereas for E. acuta and E. dietrichiana seed germination percentages gradually increased over a number of years. These two dormancy patterns may contribute to coexistence, since coexistence is enhanced by a long-lived resistant phase in the life history of species and by temporal variability in germination. There were also spatial inconsistencies in patterns of dormant fractions. Burial in the deeper zones of the marsh-like Billybung Lagoon had an inhibitory effect both on germinability and on germination rates of E. acuta and E. dietrichiana seeds. All but E. acuta showed some degree of seasonal dormancy, but this pattern was also not consistent in space. Explanations for zonation should concentrate on other life-history phases, such as dispersal and seedling survival.
Within-canopy gradients of nitrogen and photosynthetic activity of Eucalyptus nitens and Eucalyptus globulus in response to nitrogen nutrition
Authors: Close D. C. , Battaglia Michael , Davidson Neil J. , Beadle Chris L.
Published: February 2004

Growth of plantation eucalypts responds strongly to applied nitrogen (N). Above-ground biomass accumulation, gas exchange and foliar N per unit leaf area (Narea) along vertical and lateral gradients within a canopy were assessed in Eucalyptus nitens (Deane & Maiden) Maiden cuttings in a glasshouse experiment (E.�nitensglasshouse cuttings) and E. globulus Labill. saplings in a field trial (E. globulusfield saplings) under varying levels of applied N. A large range of maximum net photosynthesis (Amax) and Narea was observed among different leaf-age classes (apical, expanding, mature and old) within vertical and lateral gradients in both E. nitensglasshouse cuttings and E. globulusfield saplings. In both experiments, Narea was generally positively correlated with levels of applied N but Amax was not.There was generally no relationship between Amax and Narea in either E. nitensglasshouse cuttings or E. globulusfield saplings, except in expanding and mature leaves within the vertical gradient of E. nitensglasshouse cuttings. These results contribute to the emerging consensus among workers that within species, poor correlation between Amax and Narea is often observed. Biomass data indicate that increased N application significantly increased growth in both experiments. Overall, the results of these experiments provide information that will further resolve the predictive strength of process-based models that describe growth of E. nitens and E. globulus in plantations.
Towards an understanding of population change for the long-lived resprouting tree Angophora inopina (Myrtaceae)
Authors: Tierney D. A.
Published: February 2004

In fire-prone habitats some long-lived tree species appear resilient to fire. However, fire frequency may affect recruitment patterns. This study investigates the reproductive features of the long-lived tree species Angophora inopina Hill in recognised priority conservation areas with a high fire frequency. Plants exhibit high survival rates when burnt and respond to fire events with high rates of growth, flowering and seed set. Aged capsules on plants contain few seeds but released seeds germinate readily, suggesting high viability, low dormancy and limited seed storage in aerial or soil seed banks. Population modelling indicates that the species will be resilient to low recruitment levels in the short term. However, over the long term, population structure is significant in determining the ability of the population to respond to recruitment cues. Thus, understanding and monitoring population structural change is a priority for this species.
Inorganic and organic substrates as sources of nitrogen and phosphorus for multiple genotypes of two ericoid mycorrhizal fungal taxa from Woollsia pungens and Leucopogon parviflorus (Ericaceae)
Authors: Midgley David J. , Chambers Susan M. , Cairney John W. G.
Published: February 2004

The abilities of six genotypes of two putative Helotiales ascomycete ericoid mycorrhizal fungal taxa from Woollsia pungens Cav. (Muell.) and Leucopogon parviflorus (Andr.) Lindl. (Ericaceae) to utilise a range of nitrogen and phosphorus compounds for growth were tested in axenic liquid culture. Although significant intra- and interspecific variation was observed, genotypes of both taxa utilised NH4+, NO3–, a range of acidic, neutral and basic amino acids and bovine serum albumen as sole nitrogen sources, along with orthophosphate, inositol hexaphosphate and DNA as sole phosphorus sources. For several isolates of each taxon, growth on the sulfur-containing amino acid cysteine was increased significantly when other forms of sulfur were excluded from the growth medium, suggesting that cysteine utilisation may represent a sulfur-scavenging strategy. Pooled data for all genotypes indicated that Taxon II produced significantly greater biomass on most substrates; however, in no case did this differ by an order of magnitude or more. Both taxa thus appear likely to have broadly similar abilities to obtain nitrogen and phosphorus from organic substrates on soil.
Ecological and physiological explanations for the restriction of a Tasmanian species of Ozothamnus to a single population
Authors: Leeson K. E. , Kirkpatrick J. B.
Published: February 2004

Vascular plant species that occur in only one population are surprisingly frequent, and not only on oceanic islands. The potential causes of this extreme restriction include the anthropogenic, the historic, the biological and the ecological. Ozothamnus reflexifolius, a one-population composite shrub occurs in an environment unaffected by human activity and is unlikely to be a neoendemic. It does occupy an environment of extreme aridity in a centre of local endemism, indicating a relict status. The species composition of the vegetation containing O. reflexifolius is distinct from the species composition of the surrounding forest. O. reflexifolius is fecund and has seeds with adaptations for potential wind dispersal to other rock plates, which are not in short supply in the vicinity. However, germination trials indicated that O. reflexifolius seeds have a short period of viability. Annual growth rings in the stems of the species are directly correlated with the number of sympodial branchings and shrub height. The age structure of the population implies continuous regeneration. The varying aspects of the large rock plate on which the distribution of O. reflexifolius is centred would prevent loss of the whole population in any fire, a common event in the area, whereas other rock plates in surrounding areas do not have this protection. The species may colonise, and then be destroyed by fire on surrounding rock plates, while being secure in its central population.
Phylogenetics and chromosomal evolution in the Poaceae (grasses)
Authors: Hilu Khidir W.
Published: February 2004

The wide range in basic chromosome number (x = 2–18) and prevalence of polyploidy and hybridisation have resulted in contrasting views on chromosomal evolution in Poaceae. This study uses information on grass chromosome number and a consensus phylogeny to determine patterns of chromosomal evolution in the family. A chromosomal parsimony hypothesis is proposed that underscores (1) the evolution of the Joinvilleaceae/Ecdeiocoleaceae/Poaceae lineage from Restionaceae ancestors with x = 9, (2) aneuploid origin of x�=�11 in Ecdeiocoleaceae and Poaceae (Streptochaeta, Anomochlooideae), (3) reduction to x = 9, followed by chromosome doubling within Anomochlooideae to generate the x = 18 in Anomochloa, and (4) aneuploid increase from the ancestral x = 11 to x = 12 in Pharoideae and Puelioideae, and further diversification in remaining taxa (Fig. 3b). Higher basic chromosome numbers are maintained in basal taxa of all grass subfamilies, whereas smaller numbers are found in terminal species. This finding refutes the 'secondary polyploidy hypothesis', but partially supports the 'reduction hypothesis' previously proposed for chromosomal evolution in the Poaceae.
The influence of fire and rainfall upon seedling recruitment in sand-mass (wallum) heathland of north-eastern New South Wales
Authors: Griffith S. J. , Bale C. , Adam P.
Published: February 2004

Wallum heathland is extensive on coastal sand masses in north-eastern New South Wales and south-eastern Queensland. Here the climate is subtropical, although monthly rainfall is highly variable and unreliable. We examined the influence of fire and rainfall on seedling recruitment in bradysporous dry-heathland [Banksia aemula R.Br., Melaleuca nodosa (Sol. ex Gaertn.) Sm.] and wet-heathland [Banksia oblongifolia Cav., B.�ericifolia L.f. subsp. macrantha (A.S.George) A.S.George, Leptospermum liversidgei R.T.Baker and H.G. Sm.] species. Two specific questions were addressed: (1) do elevated levels of soil moisture facilitate seedling recruitment; (2) is the post-fire environment superior for seedling recruitment? Field experiments demonstrated that heathland species studied here are capable of successful recruitment in atypical habitat, and this proceeds irrespective of fire and unreliable rainfall. Conditions for growth and reproduction were found to be adequate if not more favourable in dry heathland, and this outcome included species usually associated with wet heathland. Spatial and temporal trends in seedling emergence and survival were examined in relation to post-fire predation and plant resource availability. Existing ideas about wallum management and conservation are evaluated, in particular the role of fire.
Slope stability analysis of potential bank failure as a result of toe erosion on weir-impounded lakes: an example from the Nepean River, New South Wales, Australia
Authors: Hubble T. C. T.
Published: February 2004

The consequences of weirs present on the Upper Nepean River on the long-term slope stability of both vegetated and devegetated riverbanks were investigated using models that account for the reinforcement of bank sediments by tree roots. The effects of the weirs in concert with channel widening and deepening caused by dredging in 1970s and 1980s, as well as natural processes, have turned the Upper Nepean from a small upland river into a series of quiet, narrow lakes, measuring 3–5 m deep, 30–70 m wide and several kilometres long. The surface of these lakes is located currently within the steep mid-bank zone. Wind-generated waves have eroded 1–3-m high scarps in the mid-bank region. These scarps are receding laterally at an average rate of 10 cm per year and this process is gradually undermining and destabilising the upper banks. In contrast, the mass of water impounded by the weirs currently acts to provide lateral support to the banks and improves their stability. Therefore, the existence of the weirs and their impounded lakes has currently both positive and negative effects on bank stability. The retention of the weirs will promote continued erosion at the waterline of the weir lakes that will eventually lead to the destabilisation and collapse of both vegetated and devegetated banks during future large floods. Demolition of the weirs would also lead to a renewed phase of bank failure during future floods as the stabilising effects of the weir lakes on the banks would be removed. The size of eventual failures will be larger and the distribution of such failures probably more widespread if the weirs are retained.
Broad-scale environmental gradients among estuarine benthic macrofaunal assemblages of south-eastern Australia: implications for monitoring estuaries
Authors: Hirst Alastair J.
Published: February 2004

The importance of abiotic factors in explaining patterns of estuarine benthic macrofaunal community structure was examined on a broad spatial scale across south-eastern Australia. Macrofaunal communities were surveyed using an Ekman grab and a modified epibenthic sled (dredge) at each sampling site: data for 24 environmental variables were also collected. Twenty-eight estuaries were sampled on a single occasion during late summer at three stratified locations within each estuary (upper, mid and lower). Macrofaunal community composition was best explained by a common environmental gradient summarising variation in both salinity and longitude. Hence, although the distribution of macrofaunal taxa can be clearly linked to changes in salinity, the geographical position of the sites along an east–west axis, rather than a generalised down-stream gradient, appears to best explain the data. This association was primarily linked to broad-scale changes in estuarine morphology across the geographical range of this survey. A sediment-based environmental gradient among grab samples, but not dredge samples, reflected the largely infaunal nature of the grab samples. In general, the present survey did not support the classification of estuarine assemblages on the basis of a range of physical parameters but, instead, emphasised the continuity of estuarine benthic macrofaunal community structure on a broad spatial scale.
Ramp disturbance - ramp response: a simple model for wetland disturbance ecology
Authors: Angeler David G. , Rodrigo Maria A.
Published: February 2004

In the present study, we report on the responses of the picoplanktonic cyanoprokaryote Synechococcus sp. to a summer drawdown in a Mediterranean floodplain wetland, using water level decrease as a measure of the gradual increase of disturbance over time, defined as a ramp disturbance. Simulating the gradual confinement of fish biomass during the drought event in an enclosure study, we found that the density of Synechococcus did not change significantly in response to fish-mediated changes in trophic state and food web compared with a fishless control. Instead, we observed a positive correlation of water levels and Synechococcus abundance in all enclosures, indicative of a ramp response to the ramp disturbance. Planktonic organisms, although largely neglected by wetland scientists, seem to be very useful model organisms for identifying cause–effect mechanisms in wetland disturbance ecology.
Onset and persistence of cyanobacterial blooms in a large impounded tropical river, Australia
Authors: Bormans Myriam , Ford Phillip W. , Fabbro Larelle , Hancock Gary
Published: February 2004

The dynamic interplay between physical, chemical and biological factors in the development and persistence of cyanobacterial blooms in impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded in the Fitzroy River, Queensland, Australia, which is a typical, impounded lowland tropical river. Post-flood turbidity reduced the available light in the well-mixed water column to levels insufficient for cyanobacterial growth. Only when the water column stratified and the slowly sinking particles dropped from the surface layer did the ratio of surface mixed layer depth to euphotic depth approach 1, allowing cyanobacterial growth. By the time the light climate became favorable, most of the dissolved nutrients had been scavenged from the water column by settling particles or sequestered by fringing macrophytes and other biogeochemical processes. Cyanobacterial blooms dominated by Cylindrospermopsis raciborskii persisted for several months until the next flood flushed the system. The cyanobacterial species dominating that environment were very small and had high specific phosphorus uptake rates. Their nutrient requirement was met by transfer across the oxycline driven by regular high wind mixing events, entraining nutrient-rich bottom waters. Nutrient fluxes from the sediments into the anoxic bottom layer were sufficient to replace the bottom nutrients lost to the surface layer.
Variation in abundances of herbivorous invertebrates in temperate subtidal rocky reef habitats
Authors: Vanderklift Mathew A. , Kendrick Gary A.
Published: February 2004

The present study assessed variation in the abundances of large herbivorous invertebrates in south-western Australia. There was some habitat partitioning between different parts of the reef: of the most frequently recorded species, the sea urchins Phyllacanthus irregularis and Centrostephanus tenuispinus were found primarily at the base of steep rock faces, whereas the gastropods Turbo torquatus and Australium squamifera were found primarily on open sections of reef. The sea urchin Heliocidaris erythrogramma was evenly distributed between these two habitats. For C. tenuispinus and H. erythrogramma, differences among locations (separated by tens to hundreds of kilometers) were the main source of variation in abundances. Phyllacanthus irregularis was more evenly distributed among locations. Abundances of sea urchins at each reef varied little over 26 months, suggesting low mortality and low recruitment. Turbo torquatus and A. squamifera varied significantly in abundance among reefs separated by < 10 km, although these differences were influenced by fluctuations over time. Broad patterns in abundances were evident: overall, abundances of herbivorous invertebrates were low, but certain areas supported high abundances. This suggests that herbivory may be a minor process in this region; however, the importance of herbivory at reefs with and without high abundances of herbivores deserves further attention.
Classifying landform at broad spatial scales: the distribution and conservation of wetlands in New South Wales, Australia
Authors: Kingsford R. T. , Brandis K. , Thomas R. F. , Crighton P. , Knowles E. , Gale E.
Published: February 2004

Relatively few large-scale inventories of the world's wetlands exist because of the difficulties of spatial scale, associated cost and multiple objectives, often temporally confounded, that drive classification. The extent of wetlands across a large part of Australia (New South Wales, 80.6 million ha) was determined using satellite image analyses. These data allowed analyses of the distribution of wetlands, their conservation status and potential threats at different spatial scales; that is, State, coastal and inland, and catchment. Approximately 5.6% of New South Wales is wetland (4.5 million ha), mostly (96%) in inland river catchments. Broad classification allowed identification of the extent of wetland types: (i) floodplains (89%); (ii) freshwater lakes (6.6%); (iii) saline lakes (< 1%); (iv) estuarine wetlands (2.5%); and (v) coastal lagoons and lakes (1.5%). Conservation reserves protect only 3% of wetland area. The analyses identified the north-west as the key area for wetland conservation as most other catchments have lower wetland extent and more potential threatening processes. The first stage of a large-scale inventory is to determine the extent and location of wetlands, with immediate benefits for strategic conservation and management. Other objectives (e.g. classification, biotic composition, hydrology and threats) seldom have sufficient data available for large-scale inventories but can be completed later with resources.
Habitat and mutualism affect the distribution and abundance of a shrimp-associated goby
Authors: Thompson A. R.
Published: February 2004

To elucidate factors that affect patterns of habitat use by a goby, Ctenogobiops feroculus, which interacts mutualistically with an alpheid shrimp, Alpheus djeddensis, goby density and habitat type were surveyed along the north shore of Moorea, French Polynesia. Although linear and quadratic multiple regression models both described the relationship between goby density and habitat as being statistically significant, more than twice the variation was accounted for by the quadratic model compared with the linear model. Further evaluation using univariate scatter plots confirmed that goby density correlated non-linearly with habitat as maximal goby density occurred in locations with approximately 71% sand and 29% rubble. Next, an aquarium-based, habitat choice experiment demonstrated that shrimp prefer to burrow in sand–rubble compared with pure sand, and that shrimp are unable to build tunnels in pure sand because burrows collapse in this substrate. This research shows that habitat choice by one organism (e.g. a shrimp) can, because of positive interactions, affect the distribution of another species (e.g. a goby). In addition, it highlights the importance of assessing non-linear relationships in studies of habitat use and, when appropriate, using statistical methods that do not rely on linear assumptions.
Endolithic algae photoacclimate to increased irradiance during coral bleaching
Authors: Fine Maoz , Steindler Laura , Loya Yossi
Published: February 2004

The photoacclimation of endolithic algae (of the genus Ostreobium) inhabiting the skeleton of the Mediterranean coral Oculina patagonica during a bleaching event was examined. Pulse amplitude modulated (PAM) chlorophyll fluorescence techniques in situ were used to assess the photosynthetic efficiency of endolithic algae in the coral skeleton and the symbiotic dinoflagellates (zooxanthellae) in the coral tissue. Relative photosynthetic electron transport rates (ETRs) of the endolithic algae under bleached areas of the colony were significantly higher than those of endolithic algae from a healthy section of the colony and those of zooxanthellae isolated from the same section. Endolithic algae under healthy parts of the colony demonstrated an ETRmax of 16.5% that of zooxanthellae from tissue in the same section whereas endolithic algae under bleached sections showed ETRmax values that were 39% of those found for healthy zooxanthellae. The study demonstrates that endolithic algae undergo photoacclimation with increased irradiance reaching the skeleton. As PAM fluorometry has become a major tool for assessing levels of stress and bleaching in corals, the importance of considering the contribution of the endolithic algae to the overall chlorophyll fluorescence measured is highlighted.
Patterns of composition and abundance in macroinvertebrate egg masses from temperate Australian streams
Authors: Reich P.
Published: February 2004

Quantitative samples of lotic invertebrate egg masses were collected on two occasions from three riffles along two rivers within the Acheron River catchment, south-eastern Australia. Sampling was stratified to compare the abundance and composition of egg masses on submerged rocks with rocks that protruded above the water surface within each of three substrate size classes. The egg mass fauna of both rivers was found to be both species rich and abundant. Egg masses belonging to Diptera and Trichoptera represented the majority of material collected, with approximately 70% of all taxa common to both rivers. In particular, egg masses of Chironomidae, Hydrobiosidae, Hydroptilidae and Hydropsychidae dominated most samples numerically. Descriptions of the egg masses belonging to 17 taxa are provided, as well as preliminary estimates of hatching times and observations of egg-laying and post-hatching behaviour for some species. Large rocks (> 30 cm maximum diameter) that protruded above the water surface consistently yielded the highest number of egg masses for all common taxa. For common taxa, between 74% and 100% of all egg masses were found on large emergent rocks. Of the common taxa, little variation in egg mass abundance was detected between sampling times or between sites within each river. Exceptions were hydroptilids and chironomids, which were completely absent from some time/site combinations, suggesting a degree of synchrony in egg-laying behaviour. For all common taxa, the greatest source of variation in egg mass numbers appeared at the level of individual rocks, where a high degree of spatial aggregation was apparent (as described by Lloyd's index of patchiness).
Inter‐ and intra‐cultural variations in self‐other boundary: A qualitative‐quantitative approach
Authors: Li Han Z.
Published: February 2004

Past research on the theories of self‐construal and individualism‐collectivism in cross‐cultural contexts presents inconsistent and inconclusive results. Some researchers have seriously questioned the validity of major instruments measuring self‐construal across cultural groups. To address the validity issue, this study developed quantitative measures from ethnographic data. In five scenarios mapping self to close‐other boundaries, 171 Anglo‐Canadians and 224 Mainland Chinese were asked to make a decision and offer a reason for the decision. Two intriguing findings emerged from the data. (1) In comparison with Anglo‐Canadians, Mainland Chinese were more likely to share material belongings with close‐others and less likely to share their thoughts/opinions. The first part of this finding provides unequivocal support for the theories of self‐construal and individualism‐collectivism, whereas the latter part challenges an important assumption of these theories, which contends that collectivists should be more likely than individualists to share everything they own (including opinions) with close‐others. This unconventional finding proposes the division of material belongings and thoughts/opinions sharing of the self‐other boundary in future cross‐cultural self‐construal research. (2) There were significant differences in the reasons Canadians and Chinese offered for what they would or would not do in a specific situation. For example, the reasons for not telling the truth about a roommate's nonmatching outfit were “tastes differ from person to person” for a Canadian and “I don't tell others what I think of them” for a Chinese. The Canadians clearly show respect for the other's personal preference and the Chinese were thinking “what can I benefit from telling her the truth?” It was reasoned that underneath the giving and generous Chinese lies a shrewd mind, and underneath the frank Canadian lies a materialistic mind. In conclusion, this article contributes to the field in that it reports pioneering research, via both qualitative and quantitative means, on sharing material belongings and opinions/thoughts in samples from individualistic and collectivistic cultures. The findings of this study illustrate, specify, and challenge the universal utility of the theories of self‐construal and individualism‐collectivism.
Personal versus interpersonal contributions to depressive symptoms among Hong Kong adolescents
Authors: Stewar Sunita Mahtani , Byrne Barbara M. , Lee Peter W.H. , Ho L.M. , Kennard Betsy D. , Hughes Carroll , Emslie Graham
Published: February 2004

Cross‐cultural theory proposes that an essential distinction between cultures lies in the extent to which individual members see themselves as either independent agents preferentially valuing agency and efficacy, or as embedded within a social context preferentially valuing interpersonal relationships. A nonreferred sample of 605 boys and 503 girls from Hong Kong provided information regarding: (1) perceptions of their personal self‐efficacy or beliefs regarding their own ability to master challenges they face; (2) the degree of harmony in their interpersonal (peer and family) relationships; and (3) depressive symptoms as an assessment of their mood. Cognitive theories of emotions propose that both the individual's assessment of his/her self‐efficacy and of his/her relationships influence mood. Hypotheses, based on cross‐cultural theory, were that in this collective culture, interpersonal evaluations would predict more of the variance in mood than would personal self‐efficacy. Contrary to Western sex‐differences literature, it was predicted that the effect of interpersonal harmony on mood would be equally pronounced for girls and for boys. Structural equation modelling was used to test causal models. Consistent with findings from the West, evaluations of personal self‐efficacy as well as interpersonal relationship harmony were significantly associated with depressed mood. Consistent with cultural theory, interpersonal relationship harmony was more strongly associated with mood than was personal self‐efficacy for the entire sample of adolescents. In contrast to findings of sex differences in the salience of relationships in the West, the prediction of interpersonal relationships to mood was equal for boys and girls in Hong Kong. This preliminary study extends models of cognitive concomitants of mood disruption to a non‐Western culture, and provides a framework to understand relative contnbutors to mood in adolescence. The findings tentatively suggest that treatment for depressive mood in Chinese populations should prioritize enhancement of the perceived quality of interpersonal relationships over increasing a sense of mastery.
Chinese writing system and learning to read
Authors: Shu Hua
Published: February 2004

One of the obvious characteristics of the Chinese writing system is its visual complexity. How do children develop their reading and writing ability in such a system? The areas we address in the present study include: (1) The basic unit in character recognition and writing of Chinese children. (2) The role of familiarity of components and the position frequency of components in character recognition and writing. In the first experiment, the subjects were first‐, second‐, fourth‐, and sixth‐graders. Children were asked to delay copy five types of characters: familiar single characters, familiar compound characters, unfamiliar compounds with familiar components, unfamiliar compounds with unfamiliar components, and noncharacters, with the components in impossible positions. The results show that older children were affected more by the familiarity and the position frequency of components in the delayed copy task. In the second experiment, the subjects were from the same grades. Children were asked to carry out lexical decision for five types of characters: real compound characters, pseudocharacters with well‐formed structure and real components, noncharacters with ill‐formed structure but real components, and noncharacters with well‐formed structure but nonreal components. The results show that children can be aware of the ill‐formed structure early, and become aware of well‐formed structure but nonreal components as they grow older. The results suggest that the component of character is the basic unit in children's lexical representation. Familiarity of components and the position frequency of components in characters affect children's character recognition and writing.
Cognitive neuroscience in China
Authors: Zhou Xiaolin , Luo Yue‐jia
Published: February 2004

In the last decade, cognitive neuroscience in China has advanced in at least four aspects: first, specialized research institutes and bodies have been set up throughout the nation; second, more and more high‐tech research facilities and approaches have been adopted by domestic researchers; third, international conferences on cognitive neuroscience have been held in Mainland China; and finally, publications relating cognitive processes to neural activation and functioning have increased. This paper selectively reviews research on perception and face recognition, attention, language, memory, and disorders in cognitive brain functions carried out by scientists in Mainland China. For visual perception, some excellent work has been carried out to investigate the neural mechanisms of perceptual priming, perceptual grouping, and perception of global/local properties in compound stimuli. For attention, much work is on issues such as the time course of brain activation in selective attention, the patterns of event‐related potentials in visual and auditory selective attention, and the effect of pre‐cueing on spatial attention. Because the Chinese language has many unique characteristics in phonological and syntactic systems and in the writing system, much research carried out in China takes advantage of these characteristics, trying to separate the universal and language‐specific aspects of language processing and their neural correlates. Memory research is mainly at neuropsychological and neurobiological levels. Disorders of cognitive functioning and their underlying impairments in the brain are attracting more and more attention. The paper concludes that as the Chinese economy is growing fast, more resources will be poured into basic research. Thus, systematic research in various fields of cognitive neuroscience by Chinese scientists is no longer a dream. It is reasonable to expect that research in this field will be accelerated in China and become an important force in the world in the near future.
The teaching of mathematics in Chinese elementary schools
Authors: Zhang Houcan , Zhou Yuren
Published: February 2004

China is a country with a long history and glorious civilization. Its tradition of putting emphasis on early education, especially children's learning of mathematics, is well known throughout the world. The superior achievements of elementary school students in mathematical learning have been attributed to the unique characteristics of the Chinese language, the simplicity of the Chinese number naming system, and the specific social environmental influence in Chinese society. Aside from the logical reasoning characteristics of the Chinese language, people usually count things in numerical order, e.g., Weekday 1, Weekday 2; Month 1, Month 2, etc., so that Chinese children become familiar with numbers at an early age, and are skillful in mental arithmetic operations. Training in good computational skills is crucial in the early period of mathematics learning. By use of the multiplication table, a cultural heritage of more than 2000 years that consists of a set of rhythmic formulae of multiplications, children can easily recall the product of two single‐digit numbers quickly and accurately, and find the quotient of a division directly. Mathematics teaching in elementary schools plays an essential role in the development of children's mathematical thinking ability, always a core task of teaching in China. Elementary school teachers have initiated various teaching methods to promote children's thinking to follow the course from the concrete to the abstract. Some of these effective methods are introduced in this paper. In the educational reform of China, the Ministry of Education proclaimed a new standard for the teaching of mathematics courses in elementary schools. Due to the availability of computers, some changes have been made in the requirements for written calculations. Intuitive thinking as well as creative abilities are to be cultivated. In order to meet the new standards, the role of the teacher is emphasized. The teaching/learning plan will be an interactive programme between teacher and students.
The involvement of executive functions in prospective memory performance of adults
Authors: Martin Mike , Kliegel Matthias , McDaniel Mark A.
Published: February 2004

The present study examines the relationship between prospective memory performance and executive functioning. The four phases of the prospective memory process—intention formation, intention retention, reinstantiation of the intention, and intention execution—are assumed to require different amounts of executive processing, most of which is demanded in the phases of intention formation and intention execution. At present, though, it is still unclear whether, and to what extent, prefrontal executive systems are involved in different kinds of prospective memory tasks, as some findings suggest that prospective memory might rather rely on nonstrategic processes that are unlikely to depend on prefrontal executive systems. Therefore, this study focuses on the following questions: (1) to what degree does executive functioning predict prospective memory performance in different standard prospective memory tasks and, furthermore, are certain executive measures better predictors than others; (2) are age‐related effects in different prospective memory measures due to individual differences in executive functioning; and (3) do age‐related differences in prospective memory exist that are not explained by individual differences in executive functioning. In a sample of 80 adults (20‐80 years), we applied four instruments to measure prospective memory: a traditional single‐task paradigm, two more complex tasks—one time‐based and one event‐based—and a highly complex multi‐task paradigm. We further assessed a broadly defined construct of executive functioning using several standard neuropsychological tests. Results showed that executive functioning did not predict performance in the simple single‐task paradigm. However, executive functioning, but not age, predicted performance in the two more complex standard tests of prospective remembering, and both executive functioning and age predicted performance in the most complex paradigm. In sum, the obtained data underline the assumption that frontal/ executive functions are related to prospective memory performance across a range of prospective paradigms. It also seems clear that age differences in prospective memory performance partially depend on age‐related individual differences in frontal/executive functions.