bluuebunny/crossref_metadata_2025 huggingface dataset:
Specification and differentiation processes of secondary mesenchyme‐derived cells in embryos of the sea urchin Hemicentrotus pulcherrimus
Authors: Tokuoka Miki , Setoguchi Chihiro , Kominami Tetsuya
Published: March 2003

Four types of mesoderm cells (pigment cells, blastocoelar cells, coelomic pouch cells and circumesophageal muscle cells) are derived from secondary mesenchyme cells (SMC) in sea urchin embryos. To gain information on the specification and differentiation processes of SMC‐derived cells, we studied the exact number and division cycles of each type of cell in Hemicentrotus pulcherrimus. Numbers of blastocoelar cells, coelomic pouch cells and circumesophageal muscle fibers were 18.0 ± 2.0 (36 h post‐fertilization (h.p.f.)), 23.0 ± 2.5 (36 h.p.f.) and 9.5 ± 1.3 (60 h.p.f.), respectively, whereas the number of pigment cells ranged from 40 to 60. From the diameters of blastocoelar cells and coelomic pouch cells, the numbers of division cycles were elucidated; these two types of cells had undertaken 11 rounds of cell division by the prism stage, somewhat earlier than pigment cells. To determine the relationship among the four types of cells, we tried to alter the number of pigment cells with chemical treatment and found that CH3COONa increased pigment cells without affecting embryo morphology. Interestingly, the number of blastocoelar cells became smaller in CH3COONa‐treated embryos. In contrast, blastocoelar cells were markedly increased with NiCl2 treatment, whereas the number of pigment cells was markedly decreased. The number of coelomic pouch cells and circumesophageal muscle fibers was not affected with these treatments, indicating that coelomic pouch and muscle cells are specified independently of, or at much later stages, than pigment and blastocoelar cells.
Expression of crystallin genes in embryonic and regenerating newt lenses
Authors: Mizuno Nobuhiko , Agata Kiyokazu , Sawada Kaichiro , Mochii Makoto , Eguchi Goro
Published: March 2003

The spatio‐temporal expression of three crystallin genes (αA, βB1 and γ) in the developing and regenerating lenses of newt was compared by in situ hybridization in lens differentiation in normal development with during regeneration. In normal development, all crystallin transcripts were first detected at the same stage in the posterior region of the lens vesicle (McDevitt's lens development stage V) and continued during lens fiber differentiation of the posterior cells into the primary lens fiber cell differentiation (McDevitt's lens development stage VII–VIII). At later stages, the expression of the three genes was restricted to the secondary lens fibers and gradually became undetectable in primary lens fibers (McDevitt's lens development stage X). The signal for γ‐crystallin was never detected in lens epithelium at any stage, whereas signals for αA‐ and βB1‐crystallin were detected in the lens epithelium at the stage when the primary lens fiber mass was formed. During lens regeneration, signals for the three crystallins were first detected at the same stage at the ventral margin of a regenerating lens vesicle (Sato's lens regeneration stage IV). The expression patterns of three crystallin genes were similar to those in normal development (Sato's lens regeneration stage V–X). The expression pattern of the crystallin genes in normal lens development fundamentally resembles that during lens regeneration, suggesting the absence of unique expression programs of crystallin genes for lens regeneration not found in ontogeny.
Blastopore formation and dorsal mesoderm induction are independent events in early Cynops embryogenesis
Authors: Suzuki Akio S. , Sakaguchi Koji , Katagiri Mineko , Ueki Megumi , Kaneda Teruo
Published: March 2003

The independent roles of blastopore formation and dorsal mesoderm induction in dorsal axis formation of the Cynops pyrrhogaster embryo were attempted to be clarified. The blastopore‐forming (bottle) cells originated mainly from the progeny of the mid‐dorsal C and/or D blastomeres of the 32‐cell embryo, but were not defined to a fixed blastomere. It was confirmed that the isolated dorsal C and D blastomeres autonomously formed a blastopore. Ultraviolet‐irradiated eggs formed an abnormal blastopore and then did not form a dorsal axis, although the lower dorsal marginal zone (LDMZ) still had dorsal mesoderm‐inducing activity. Involution of the dorsal marginal zone was disturbed by the abnormal blastopore. These embryos were rescued by artificially facilitating involution of the dorsal marginal zone. Suramin‐injected and nocodazole‐treated blastulae did not have involution of the dorsal marginal zone, although the blastopore was formed. Neither embryos formed the dorsal axis. The dorsal mesoderm‐inducing activity of the LDMZ in the nocodazole‐treated gastrulae was still active. In contrast, the LDMZ of the suramin‐injected embryos lost its dorsal mesoderm‐inducing activity. bra expression was activated in the nocodazole‐treated embryos but not in the suramin‐injected embryos. The present study suggested that (i) the dorsal determinants consist of blastopore‐forming and dorsal mesoderm‐inducing factors, which are not always mutually dependent; (ii) both factors are activated during the late blastula stage; (iii) the dorsal marginal zone cannot specify to an organized notochord and muscle without the involution that blastopore formation leads to; and (iv) the localization of both factors in the same place is prerequisite for dorsal axis formation.
Growth analysis of the self‐thinning stands of Pinus densiflora Sieb. et Zucc.
Authors: XUE LI , HAGIHARA AKIO
Published: March 2003

The competition‐density (C‐D) effect for self‐thinning Pinus densiflora Sieb. et Zucc. stands was analyzed. The relationship between biological time τ and physical time t followed a hyperbolic curve. The coefficients At and B included in the reciprocal equation of the C‐D effect in self‐thinning stands (i.e. 1/w=At+B), where w and ρ, respectively, represent the mean stem volume and the realized stand density, were calculated at each time. With increasing τ, the coefficient At increased abruptly up to a maximum value, and then decreased gradually to a constant level, whereas the coefficient B decreased exponentially. The relationship between the realized stand density ρ and the initial stand density ρi was confirmed to follow the equation: 1/=1/i+, where 1/ɛ represents the asymptotic stand density at a given time. The ɛ‐τ relationship was represented by the equation: =p(eμ−1), where p and μ are constants. The density in the self‐thinning stands tended to converge to the same density level after a sufficient lapse of time, irrespective of the difference in initial stand density. The time‐trajectory of the mean stem volume and asymptotic stand density on logarithmic coordinates moved gradually toward the self‐thinning line with a slope of approximately −3/2, whereas the time‐trajectory of the mean stem volume and full stand density moved initially along the self‐thinning line with a slope of approximately −3/2, and then changed to move along the maximum yield line with a slope of −1.0.
Multiple mating and lifetime reproductive output in female dobsonflies that receive nuptial gifts
Authors: Hayashi Fumio
Published: March 2003

In mating of the dobsonfly, Protohermes grandis (Thunberg), the male attaches the spermatophore externally to the female genitalia. The spermatophore includes a large gelatinous mass which the female detaches and feeds on after mating. While the female consumes this nuptial food gift, sperm is evacuated from the remaining portion of the spermatophore (sperm package) into her reproductive tract. Under laboratory conditions, mated females maintained receptivity throughout their lifetime, and they remated even on the day following copulation. A single insemination may supply enough sperm, as females mated only once deposited fertile eggs throughout life and, when dissected after death, all females had sperm in the spermatheca. There was a positive correlation between longevity and the number of matings. Lifetime fecundity also increased as mating multiplied. However, the size of eggs and hatchlings was not influenced by the number of matings. It seems that large spermatophore consumption by female P. grandis provides nutrients that increase fitness not in offspring quality, but in their quantity.
Seed dispersal curve of a Mediterranean myrmecochore: Influence of ant size and the distance to nests
Authors: Gómez Crisanto , Espadaler Xavier
Published: March 2003

Euphorbia characias is a Mediterranean spurge with a diplochorous dispersal system: after a ballistic dispersal that scatters the seeds, some ant species find and retrieve the seeds to their nest (myrmecochorous dispersal). The seed dispersal curve generated by ants in an abandoned field was described and partitioned according to ant size and to the distance to nest entrance from where seeds fell after ballistic dispersal. Both variables (ant size, distance to nest) affected dispersal distance. The seed dispersal curve showed a peak at short distance (median = 1 m) and a tail extending to 9.4 m. The peak and the tail are explained differently. Short distances are usually generated by small ants (Pheidole pallidula and Tapinoma nigerrimum; 0.56 ± 0.41 m [n = 48]) both from the nearest or farther nest entrances. The tail of the curve is generated disproportionately by big ants (Aphaenogaster senilis and Messor barbarus; 2.09 ± 1.71 m [n = 61]) from farther nests. Seeds have a much greater probability (P = 0.734) of being transported to nests which are not the nearest. This effect is largely due to transportation by big ants.
Removal and predation of Quercus liaotungensis acorns by animals
Authors: Wang Wei , Ma Keping , Liu Canran
Published: March 2003

Two types of acorns (fresh, current‐year acorns and old, previous‐year acorns) of Quercus liaotungensis were used under two different situations (night and day) to examine the removal and predation by animals in the field. The acorns disappeared very fast. During the day, all of the 280 ‘this‐year’ acorns (TA) and all of the 140 ‘last‐year’ acorns (LA) were removed by animals within 6 h and 5 h, respectively, after acorns were put in place. At night, all of the 280 TA acorns were removed by animals within 10 h after acorns were distributed, and 71 out of 140 LA acorns were removed within 10 h. Animals consumed a small proportion of acorns in situ (11.8%). The number of TA acorns consumed in situ at night was higher than that during the day. During the day, the number of LA acorns consumed in situ was significantly higher than TA acorns. This result suggests that the most important harvesters of Q. liaotungensis during the day were visually orientated diurnal animals, and the most important harvesters at night were olfactorily orientated nocturnal animals. Furthermore, the latter are more efficient than the former at finding and harvesting acorns, because they spend less energy on harvesting the same number of sound acorns.
Effects of flooding on a wetland bird community
Authors: Shimada Tetsuo , Bowman Aaron , Ishida Mitsuru
Published: March 2003

The Lake Izunuma–Uchinuma was extensively flooded in 1998 and vast areas (approximately 200 ha) of rice fields were submerged for the first time since the land was reclaimed in 1963. When the numbers of birds in 1998 were compared with those in normal years (1995–1997), the numbers of black‐crowned night herons (Nycticorax nycticorax L.), cattle egrets (Bubulcus ibis L.) and black kites (Milvus migrans Boddaert) increased during the flooding, and the numbers of ducks, especially dabbling ducks (seven species of 11 Anas spp.) were high even after the flooding, while the numbers of the little grebe Tachybaputus ruficollis Pallas were diminished by the flooding.
Competition along a nutrient gradient: A case study with Daucus carota and Chenopodium album
Authors: Li Bo , Watkinson Andrew R.
Published: March 2003

A binary competition experiment between carrot (Daucus carota L.) and Chenopodium album L. was conducted in a greenhouse at seven population densities and eight nutrient concentrations to investigate the effects of a nutrient gradient on plant competition in both monocultures and mixtures. The patterns of carrot biomass allocation (measured as root : shoot ratio) in monocultures and mixtures with C. album were affected by both nutrient availability and population density. Chenopodium album had a broader response to nutrient concentrations than carrot. The maximum yield of carrot in both monocultures and mixtures occurred at fourfold the standard concentration of nutrients, while C. album in both monocultures and mixtures had the maximum yield at 16‐fold the standard nutrient concentration. The yield–density relationship of carrot tended to be increasing or asymptotic at lower nutrient concentrations but parabolic at higher concentrations, whereas that of C. album was little affected by nutrient availability. Nutrient availability had a profound influence on the competitive relationships between the two species: at both low and high nutrient concentrations, C. album tended to be more competitive than carrot, while at intermediate levels of nutrients, carrot was more competitive than C. album. Our results suggest that in relation to competitive performance, the weed has a greater ability to adapt itself to varying environments than does the crop. Additionally, the relative merits of the quantitative measures of competitive ability are briefly discussed.
Magnitude of within‐patch variation in seagrass Halophila ovalis growth affected by adjacent Thalassia hemprichii vegetation
Authors: Nakaoka Masahiro , Iizumi Hitoshi
Published: March 2003

Seagrass beds in South‐east Asia sometimes consist of a mosaic of different species in monospecific patches. We examined whether the magnitude of within‐patch variation in the seagrass Halophila ovalis is affected by the presence or absence of surrounding vegetation consisting of another seagrass species Thalassia hemprichii in an intertidal flat in Thailand waters. We measured biomass and growth rates of H. ovalis at the edges and centers of two different types of patches: (i) H. ovalis patches adjoining T. hemprichii vegetation (HT patches), and (ii) H. ovalis patches adjoining unvegetated sand flats (HS patches). Furthermore, we examined the possible effects of interspecific interactions on the growth of H. ovalis by experimentally removing adjoining T. hemprichii at the edges of HT patches. The biomass of H. ovalis was greater at the patch centre than the patch edge in both types of patches. For the growth rate of H. ovalis, significant interactions were detected between patch types and positions in patches. The difference in growth was significant and more than 4‐fold between edges and centers of the HS patches, whereas the growth was not significantly different between edges and centers of the HT patches. The removal of T. hemprichii did not significantly affect the growth rate of H. ovalis at the edge of the HT patches. These findings demonstrate that the magnitude of within‐patch variation in H. ovalis growth is affected by the conditions of adjoining habitats. However, any effects of local competition with T. hemprichii on H. ovalis growth were not evident in this short‐term manipulative experiment.
Measuring fig foraging frequency of the Yakushima macaque by using automatic cameras
Authors: Otani Tatsuya
Published: March 2003

An automatic camera system was employed to reveal the fig foraging frequency of primary seed dispersers on Yakushima Island, southern Japan. Seven automatic cameras were settled on sample branches of Ficus superba (Miq.) Miq. var. japonica Miq. to record animals foraging for figs. Figs on sample branches were counted at approximately 3 day intervals. The cameras took 168 photographs including 155 pictures of Yakushima macaques and two of birds, indicating that most of the figs at the inner parts of the crowns were eaten by the macaques. There was a linear relationship between the number of macaques foraging for figs on sample branches and the number of figs that dis‐appeared within each period, suggesting that the automatic camera system was useful for estimating fig loss as a result of the foraging activity of the macaques on a branch basis.
Effects of isolates of ectomycorrhizal fungi and endophytic Mycelium radicis atrovirens that were dominant in soil from disturbed sites on growth of Betula platyphylla var. japonica seedlings
Authors: Hashimoto Yasushi , Hyakumachi Mitsuro
Published: March 2003

Effects of ectomycorrhizal fungi and endophytic Mycelium radicis atrovirens Melin (MRA) on growth of Betula platyphylla var. japonica seedlings were investigated under aseptic culture conditions. Three isolates of ectomycorrhizal fungi and two isolates of MRA were used. One MRA isolate was Phialocephala fortinii. Previous field work revealed that these isolates were dominant on the roots of B. platyphylla var. japonica seedlings grown in a mineral subsoil that had been exposed by the removal of surface soil. After a 100‐day incubation, the growth of the seedlings was significantly enhanced by the colonization of these ectomycorrhizal fungal isolates as compared with uninoculated seedlings. In contrast, the growth of seedlings was retarded by the colonization of the MRA isolates. The growth of seedlings that were co‐inoculated with ectomycorrhizal fungi and MRA was similar to that of uninoculated seedlings in most cases. These results suggest that ectomycorrhizal fungi have a beneficial effect on the growth of B. platyphylla var. japonica seedlings and that they suppress the deleterious effect of MRA. Thus, these ectomycorrhizal fungi probably have an important role in establishing B. platyphylla var. japonica seedlings during the initial stage of re‐vegetation following site disturbance by the removal of surface soil.
Fish abundance and habitat relationships in forest and grassland streams, northern Hokkaido, Japan
Authors: Inoue Mikio , Nakano Shigeru
Published: March 2003

The relationships between habitat variables and population densities of masu salmon (Oncorhynchus masou), rosyface dace (Leuciscus ezoe), Siberian stone loach (Noemacheilus barbatulus) and wrinklehead sculpin (Cottus nozawae) were examined by data collected at 55 reaches in forest and grassland streams in northern Hokkaido, Japan. Regression analysis suggested that salmon and dace densities were affected by water temperature (negative for salmon, positive for dace) and structural habitat factors (woody debris for salmon, pools for dace). Salmon density was higher in forest reaches than in grassland reaches, whereas dace density was higher in grassland reaches, suggesting that the removal of riparian forest had raised water temperature and allowed upstream invasions by dace. In contrast to salmon and dace, neither the density of loach nor sculpin differed between the forest and grassland reaches. For their densities, a negative effect of each on the other was most important, suggesting a strong effect of interspecific competition between loach and sculpin on their distributions. However, regression models also suggested that substrate heterogeneity mediated the outcome of their interspecific competition. On the basis of the results, a scenario is predicted for a fish‐assemblage change with a typical land‐development process in Hokkaido, and the importance of leaving or restoring riparian buffer for conservation and restoration of stream habitat is emphasized.
Difference in microhabitat‐related regeneration patterns between two subalpine conifers, Tsuga diversifolia and Abies mariesii, on Mount Hayachine, northern Honshu, Japan
Authors: Sugita Hisashi , Tani Masato
Published: March 2003

Seedling and tree‐establishment microhabitats of Tsuga diversifolia and Abies mariesii were examined on the herb‐ and dwarf bamboo‐dominated forest floor on Mount Hayachine, a mountain under intermediate snow conditions in northern Honshu, Japan. The four microsite types were fallen logs, buttresses, rocks and ground. The ground substratum was further divided into four subtypes by dominant undergrowth species: Lycopodium, Pteridophyllum, Carex and dwarf bamboo. The establishment of T. diversifolia seedlings on the ground was scarce, and depended mostly on non‐ground microsites (i.e. fallen logs, buttresses and rocks). The seedling establishment of A. mariesii was not dependent on specific substrata, although on the ground, establishment sites were limited to the Lycopodium subtype situated on convex sites. Among the microhabitats for seedling establishment, larger trees of A. mariesii rarely occurred on higher portions of the non‐ground microsites. In contrast, T. diversifolia could grow up to the height of canopy‐layer trees in such microsites. Thus, non‐ground microsites seem to be unsuitable for tree establishment in A. mariesii, and are probably useful microhabitats for regenerating T. diversifolia to avoid competition with A. mariesii. We also compared seedling‐establishment microhabitats for the two conifers between Mount Hayachine and two other mountain regions under different undergrowth conditions (moss‐dominated and dense dwarf bamboo‐dominated). Our findings suggested that seedling recruitment in non‐ground microsites was primarily determined by undergrowth conditions; T. diversifolia preferred such microsites where the moss‐covered area was low, and A. mariesii preferred where dwarf bamboo‐covered area was high.
Food habits of an endangered Japanese frog, Rana porosa brevipoda
Authors: Hirai Toshiaki , Matsui Masafumi
Published: March 2003

We examined the diet of an endangered frog, Rana porosa brevipoda inhabiting rice fields of western Japan, by forced regurgitation of stomach contents. The frog diet consisted of a wide variety of arthropods, and ants, beetles, dipterans, bugs, orthopterans, and spiders, which were especially prominent. These prey taxa were also collected in large numbers by sweep‐net samplings made in the frog habitat, and relative abundances of prey taxa in frog diet and those in sweep samples were found to be significantly correlated. Aquatic forms did not contribute much to the frog diet, but were found to be taken more frequently and in larger numbers in irrigated fields than in drained fields. These findings suggest that prey availability around frog habitat is very important to regulate the food items of R. p. brevipoda. On the other hand, terrestrial components of frog habitats are indicated to be important because the frog highly depended on terrestrial invertebrates. From these results, we consider it imperative to preserve terrestrial components linked with aquatic environments to conserve biodiversity in rice field ecosystems.
Quantitative evaluation of atmospheric CO2 sink into forest soils from the tropics to the boreal zone during the past three decades
Authors: Nakane Kaneyuki
Published: March 2003

A model of soil carbon cycling in forest ecosystems was applied to predict the soil carbon balance in nine forest ecosystems from the tropics to the boreal zone during the past three decades (1965–95). The parameters of carbon flows and initial conditions of carbon pools were decided based on data obtained in each forest stand. Assumptions for model calculation were: (i) primary production (i.e. litterfall and root turnover rates) increased with increasing CO2 concentrations in the atmosphere (10% per 40 p.p.m. CO2); and (ii) temperature increased by 0.6°C per 100 years, but precipitation changed little. The simulation employed a daily time step and used daily air temperature and precipitation observed near each forest stand over an average year during the last decade. The model calculations suggest that the accumulation of total soil carbon increased 8.5–10.4 tC (ton of carbon) ha−1 in broad‐leaved forests from the tropics to the cool‐temperate zone during the past three decades, but the amount of soil carbon (3.0–8.4 tC ha−1) increased much less in needle forests from the subtropical to boreal zones during the same period. There is a linear relationship between the increasing rate of soil carbon stock during the past three decades (1965–95) in forest stands concerned (RMS, % per 30 years) and annual mean temperature of their soils (T0,°C), as: RMS = 0.34T0 + 4.1. Based on the data of carbon stock in forest soil in each climate zone reported, the global sink of atmospheric CO2 into forest soil was roughly estimated to be 42 GtC (billion tons of carbon) per 30 years, which was 1.4 GtC year−1 on average over the past three decades.
Alterations in the grazing activities of cased caddisfly larvae in response to variations in predation risk and resource level
Authors: Kuhara Naotoshi , Nakano Shigeru , Miyasaka Hitoshi
Published: March 2003

Flexible behavioral response to avoid encountering predators has never been reported in lotic, cased caddisfly larvae with low mobility. However, an earlier laboratory experiment found the growth of such a caddisfly species, Glossosoma sp., decreased in the presence of a predatory sculpin, Cottus nozawae. We conducted laboratory experiments to test whether Glossosoma responses to sculpin varied according to resource level and/or time of day. Lower periphyton biomass resulted in increased movement at any time of day, but was followed by decreased grazing success of Glossosoma in the morning when they were sampled. Although sculpins were active in the morning, evening and night but never in the afternoon, movements of Glossosoma were suppressed by sculpin stimuli only in the morning, when food intake of Glossosoma also decreased, regardless of periphyton biomass. Glossosoma reduced the risk of predation by sculpin by flexibly controlling its grazing activities during the most risky period of the day (i.e. morning). Even in the morning in the presence of sculpin, lower resource levels resulted in longer movement distances similar to those in predator‐free conditions, suggesting that lower resource availability promotes predation risk in natural streams inhabited by predatory sculpin.
Characteristics of gas exchange and morphology of a spring ephemeral, Erythronium japonicum, in comparison with a sun plant, Glycine max
Authors: Sawada Shinichi , Kato Toshiaki , Sato Makiko , Kasai Minobu
Published: March 2003

Morphological characteristics and responses of gas exchanges to light intensity were examined in a typical vernal species, Erythronium japonicum Decne (E.

japonicum), grown (i) on the floor of a deciduous broad‐leaved Quercus mongolica

forest (one of its native habitats, the Q. mongolica stand); (ii) bare land

left undisturbed for 9 years after forest clearing (the bare stand); and (iii) in

a sun crop, soybean, grown for 110 days in an experimental field and for 17 days

in pots, in order to evaluate the adaptability of the photosynthetic process of this

vernal species to its shady native habitats. The daytime solar radiation, air and

leaf temperatures and leaf–air vapor pressure difference (VPD) were significantly

higher at the bare stand than at the Q. mongolica stand. When environmental

factors observed at the Q. mongolica and bare stands were reproduced in an

assimilation chamber, leaf temperatures of E. japonicum plants increased markedly

with increased radiation, whereas those of soybean plants differed little from the

respective air temperatures. The photosynthetic and transpiration rates and stomatal

conductance in the former plants placed under conditions at the Q. mongolica

stand increased with radiation and reached respective steady state values at maximum

radiation at the site; whereas, under the conditions at the bare stand, they also

increased and reached respective steady state values, but then continuously decreased

to be lower than the respective value at the Q. mongolica stand. However,

both rates and the conductance in the soybean plants under both conditions increased

significantly with radiation and reached much higher respective values at the respective

maximum radiations. Water use efficiency for E. japonicum plants was much

higher under conditions at the Q. mongolica stand than at the bare stand and

was practically equal to those for soybean plants under both conditions. Water potential

in the leaves of E. japonicum at maximum radiation at the bare stand was one‐third

that of those at the Q. mongolica stand. The potential in soybean leaves differed

little between both conditions and was roughly equal to the low value in E. japonicum

leaves at the bare stand conditions. The stomatal densities on upper and lower leaf

surfaces and the ratio of root weight to leaf area (R : L) differed little between

E. japonicum plants grown at both stands as well as between young and adult

soybean plants. However, the densities on the upper and lower surfaces of E. japonicum

were 25% and 60% of the respective values of both soybean plants.

The ratios of R : L of the E. japonicum plants were only one‐quarter that

of the young and adult soybean plants. The cooperation between these morphological

and gas exchange characteristics in E. japonicum plants is discussed in relation to adaptation to the environment in native habitats.
Pelagic food webs: Responses to environmental processes and effects on the environment
Authors: Legendre Louis , Rivkin Richard B.
Published: March 2003

Changes in both the environment and environmental research have led to the development of new protocols and approaches. These new approaches consider both the effects of changes in the global environment on living organisms (i.e. the responses of ecosystems to environmental processes) and the feedback responses of these organisms and ecosystems (i.e. the effects of living organisms on the environment). The present paper focuses on pelagic food webs in aquatic ecosystems. We examine three major effects of global environmental changes on aquatic organisms: (i) the release of pollutants and biological agents in lakes and nearshore marine waters; (ii) the loss of biodiversity and the collapse of commercially exploited resources that were heretofore renewable. We develop detailed examples of the effects of human activities on marine organisms (i.e. the effects of nutrient supply on the structure of pelagic food webs in marine systems. Finally, we examine (iii) the food‐web‐controlled exchanges of CO2 between the atmosphere and the ocean, as a feedback effect of pelagic ecosystems on the global environment with respect to the ongoing climate change.
Effects of progressive grazing of a pasture on the spatial distributions of herbage mass and utilization by cattle: A preliminary study
Authors: Hirata Masahiko , Sato Reiko , Ogura Shin‐ichiro
Published: March 2003

Spatial distributions of herbage mass and utilization were investigated at a small patch scale in a bahia grass (Paspalum notatum Flügge) pasture progressively grazed with beef cows, using a method combining sward and animal measurements. For a 6‐day grazing period, pre‐grazing herbage mass (Mpre) and rate of defoliation (D) were non‐destructively estimated every day, using an electronic capacitance probe, at 91 fixed locations (50 cm × 50 cm each) along a permanent line transect. At the same time, ingestive behavior by cows at the individual locations was measured every day, in terms of the number of visits (NV), total residence time (TR), total number of bites (NB), residence time per visit (TRV), number of bites per visit (NBV) and biting rate (RB). Spatial distribution patterns of herbage mass and utilization variables clearly illustrated which locations of the pasture were highly available, frequently visited, grazed longer, received more or faster bites and heavily defoliated during the progressive grazing. The mean and CV values of the spatial distributions showed that cows visited more locations more evenly by shifting from one location to another more frequently as the grazing progressed. The study also revealed that Mpre became more heterogeneous and D tended to be more homogeneous with the progression of grazing. The relationships between the herbage utilization variables and herbage mass showed that locations with lower herbage mass were more frequently visited, grazed longer and received more bites on the first 5 days, although the rate of defoliation was usually lower. Thereafter, neither locations with lower herbage mass nor those with higher herbage mass were preferred by cows. These results showed how vegetation patchiness and patch utilization by cows changed with decreasing feed resources in a pasture.
Second species in the Australian ant genus Peronomyrmex Viehmeyer (Hymenoptera: Formicidae)
Authors: Shattuck Steven O , Hinkley Simon
Published: March 2003

A second species of the rare Australian ant genus Peronomyrmex is described

from Victoria. This new species, P. bartoni, represents only the third time

the genus has been collected, the previous records being the holotype of P. overbecki Viehmeyer from north‐eastern New South Wales and a collection, subsequently lost, from northern Queensland.
Use of an emergency sedation protocol to assist intubation in helicopter patient retrieval in Victoria
Authors: Sams James , Kelly Anne‐Maree
Published: March 2003

Abstract

Objectives: To review emergency sedation intubation as practised in the Melbourne‐based ambulance helicopter. Specifically, to describe patient profiles, drug dosage, difficulties encountered, success rate and patient outcomes.

Methods: Retrospective review of all helicopter primary and secondary retrieval patients, who received application of the emergency sedation intubation protocol using morphine and diazepam during a 3 year period (January 1995 to December 1997). Data were collected from an audit of patient care records completed by flight paramedics and from hospital records.

Results: Emergency sedation intubation was performed on 128 patients: 103 adults and 25 children. The median dose of drugs required for emergency sedation intubation by adult patients was 20 mg morphine and 20 mg diazepam. The overall success rate for emergency sedation intubation was 94.5%, with 73.6% of these being successful intubations at the first attempt. On intubation, 54.1% of patients were fully relaxed, while a gag reflex was still present in 45.9% of patients during or just after emergency sedation intubation. Twenty‐two per cent of patients had a change in blood pressure of more than 20 mmHg. The maximum rise in blood pressure was 60 mmHg and the maximum fall was 80 mmHg.

Conclusions: Flight paramedics achieved a high success rate for intubation with the morphine/ diazepam emergency sedation intubation protocol. However, there was still a significant percentage of patients for whom more than one attempt was required to achieve emergency sedation intubation and, in almost half the patients, gag reflexes remained present either during or immediately after intubation. Additionally, some patients experienced blood pressure changes following intubation that may have potential adverse consequences in terms of compromised cerebral perfusion or rises in intracranial pressure. Consideration should be given to revision of the protocol to allow the use of neuromuscular blocking agents and alternative airway management techniques, such as cricothyroidotomy, for specified circumstances in the aeromedical environment.
Air embolism in chest trauma
Authors: Holdgate Anna , Arendts Glenn
Published: March 2003

Abstract

Air embolism is a recognized complication of penetrating chest trauma. A case of fatal air embolism is presented and the pathophysiology of both venous and arterial air embolism is described. Air embolism can be precipitated by positive intrathoracic pressure in the presence of open vascular injury and can present as unexpected cardiovascular collapse following intubation and positive pressure ventilation. Strategies for preventing air embolism include minimum airway pressures during ventilation, single lung ventilation via a double lumen tube and maintenance of adequate pulmonary venous pressure with intravenous fluids. Established air embolism is managed by patient positioning to direct air bubbles away from vital organs, aspiration of intravascular air, minimizing air bubble size and repairing the underlying injury.
Access to care: What should we be measuring?
Authors: Kennedy Marcus P
Published: March 2003

Some of the key measures on which emergency departments are judged concern access to care. In Australasia, the most common current measure of access is the percentage of patients who are seen within a specified time for each category of the national triage scale. Access measures regarding availability of in‐patient beds is less uniform, but tends to be related to the number of patients who spend longer than a specified time in the emergency department. There are, however, measurables that are demonstrative of departmental process rather than being simple waiting time quantiles. These include mean and median elapsed times, together with standard deviations and coefficient of variation for each of the indicators. These measures better describe the central tendency and spread of performance, both of which are fundamentally important to any measure of the quality of process. This paper discusses the use of these broader and more descriptive indicators of process.
Validation study of injury surveillance data collected through Queensland hospital emergency departments
Authors: Hockey Richard , Horth Adrian , Pitt W Robert
Published: March 2003

Objective: The objective of this study was to assess and validate the EDIS (Emergency Department Information System) as a means of acquiring Level 2 injury surveillance data as defined by the National Data Standards for Injury Surveillance in public hospital emergency departments in Queensland.

Methods: This validation was based on interviews with patients presenting to selected emergency departments in Queensland for treatment of an injury which was then compared to data obtained from emergency department staff completing the routine medical record for these patients using EDIS. To assess the level of coding variability and set baseline levels of agreement the data were separately coded by three experienced coders and the level of agreement evaluated. At the time of the validation emergency department staff were also asked to complete a questionnaire relating to their attitudes towards EDIS and to injury surveillance.

Results: A total of 572 cases of injury were collected during the period of the validation of which 509 (89.0%) corresponded to an injury recorded in EDIS. Demographic details collected in the emergency department data were coded correctly in almost all cases. The exception was Indigenous status where the emergency department systems recorded only 38% of the Indigenous cases correctly. Injury data fields were better than 85% complete for two sites but only 65% complete for the third. Coding agreement between Emergency Department Information System and the validation study for items relating to the injury event varied from 95% for Intent to 50% for Activity when injured. The interrater agreement analysis revealed that the highest agreement between the coders was for intent (94–96%) while the lowest was for main injury factor (63–78%). The results of the emergency department staff satisfaction survey showed a high acceptance of EDIS and injury surveillance in general.

Conclusions: This analysis demonstrates that injury surveillance is a viable proposition for most emergency departments using computerized patient management systems designed with injury surveillance in mind. Emergency department‐based injury surveillance provides a pro‐active mechanism for monitoring injuries in specific areas of known concern, identifies previously unrecognized injury events and risk factors and permits the evaluation of preventive strategies.
Intravenous lignocaine as pretreatment for intubation of patients with acute severe head injury
Authors: Monaghan Mark
Published: March 2003

Intravenous lignocaine at a dose of 1.5–2.0 mg/kg is frequently included in intubation protocols for patients with acute severe head injury. This literature review attempts to provide an evidence base for this. A Medline search and review of all relevant articles post‐1966 was undertaken. There is evidence that lignocaine has a beneficial effect on intracranial and intraocular pressures. Neuroprotection is demonstrated in some animal models. There is, however, no evidence that lignocaine improves outcome. This article recommends using lignocaine in pre‐intubation for patients where a rise in intraocular pressure is a concern (e.g. penetrating eye injury), but cannot, on evidence alone, justify its inclusion in head injury protocols.
The CDC Pacific emergency health initiative: A pilot study of emergency preparedness in Oceania
Authors: Keim Mark E , Rhyne Gary J
Published: March 2003

Objective:

Environmental emergencies and disasters are becoming more frequent in developing nations. Between 1992 and 1996, disasters affected an annual average of 4.5 million Oceania residents. Unfortunately, public health planners in the region and responders throughout the world have little evidence on which to base measures of emergency preparedness. Indicators of preparedness must be identified, implemented and evaluated before the effectiveness of emergency planning interventions can be measured accurately. The aim of this study was to perform an objective evaluation of emergency preparedness among five nations in Oceania.

Methods:

A standardized retrospective review of national‐level public health and institutional‐level hospital emergency operations plans from a convenience sample of five Pacific nations or territories was performed. In addition, in‐country interviews, observation of operations and review of documentation were conducted. The rates of affirmative responses to 957 yes/no queries in the questionnaire were tabulated according to major emergency operational planning concepts and categories of emergency support functions.

Results:

The study revealed remarkably low levels of emergency planning and preparedness among health and medical sectors of five Pacific islands.

Conclusion:

These data suggest a very low level of host national capacity for development of preparedness. Further investigation is necessary to define this need throughout this region of Oceania.See Commentary, page 143.
Reliability of modern microwave ovens to safely heat intravenous fluids for resuscitation
Authors: Delaney Anthony
Published: March 2003

Objective:

To determine if intravenous fluid heated in modern microwave ovens is warmed to a consistently safe temperature, as has been advocated in a number of texts and journals.

Methods:

Five, 1L bags of normal saline in Viaflex (Baxter Healthcare, Old Toongabie, NSW, Australia) containers were heated for 2 min on high setting in 16 different microwave ovens. The output power ranged from 650 to 1000 W. All microwave ovens were equipped with electronic timers and turntables. Initial and final temperatures were recorded with a TestoTerm 1100 electronic thermometer (Dade Behring, Lane Cove, NSW, Australia), accessing the centre of the fluid via the injection port. The average and standard deviation for each measurement was determined for each microwave oven.

Results:

In nine out of the 16 microwaves (56%) tested, the fluid had reached an average final temperature greater than 42°C and thus was greater than the recommended maximum temperature for the heating of intravenous fluids. All microwave ovens with an output power of greater than 900 W overheated the fluids. However 13/16 microwaves (81%) had a temperature range less than 3°C, thus if correctly calibrated could be appropriate for heating intravenous fluid for resuscitation.

Conclusions:

The increased output power of modern microwave ovens can lead to overheating of resuscitation fluids, if the simple algorithm currently recommended is followed, leading to potentially serious complications. Microwave heating of intravenous fluid could be a safe, simple, cheap and effective means of heating intravenous fluids for resuscitation, but care needs to be taken to calibrate individual machines to ensure a safe temperature is reached.
Prevertebral haematoma after thrombolysis: An unusual cause of airway obstruction
Authors: Semmonds Alison K , Doherty Steven
Published: March 2003

A case report of prevertebral haematoma causing airway obstruction following thrombolytic therapy for acute myocardial infarction is presented. The management options for airway obstruction, after thrombolytic therapy, are discussed.
Small emergency departments: Does size matter?
Authors: Smith Brendon
Published: March 2003

An emergency department provides care for a full spectrum of undifferentiated disorders and its size may influence how well it can do so. Outcomes research in emergency medicine is limited, although outcomes in severe trauma and acute coronary syndromes have been shown to be influenced by available facilities and expertise. A department can be too small to provide the full spectrum of emergency care, as has been documented with General Practice Casualty Units. Some research suggests that a critical mass is required to ensure acceptable outcomes. Small departments may operate in a hierarchical system, led by teaching hospitals setting practice standards. However, these may be opinion as much as evidence based and not broadly applicable as a universal practice standard. Small departments can be overwhelmed by trauma and other major cases or when the teaching hospital is unable to accept emergency patients or transfers because they are operating at capacity. Further outcomes research and audit of individual hospitals is required to determine a minimum optimum size for emergency departments. See Commentary, page 12.
Sustained‐release bupropion overdose: A new entity for Australian emergency departments
Authors: Paoloni Richard , Szekely Ilona
Published: March 2003

Bupropion hydrochloride (Zyban, Glaxo Wellcome Australia, Melbourne, Vic., Australia) was released in Australia in November 2000 as adjunctive therapy to assist with smoking cessation, having previously been used as an antidepressant in the US since 1989. The toxicity profile of bupropion hydrochloride in overdose differs considerably from other antidepressants, with prominent neurological manifestations and little cardiovascular toxicity. A case of bupropion overdose demonstrating the typical toxic syndrome is presented, together with a review of the literature and a discussion of the magnitude of the demand for bupropion and of the potential differences in presentation of overdoses in Australia.
Efficacy of ciprofloxacin in urinary tract infections and risk factors for ciprofloxacin‐resistant infections
Authors: Daniel Tai‐Yam Lee , Velayudhan Venu , Samuel Po‐Yin Kwok
Published: March 2003

Objectives: The study was undertaken to assess the safety and efficacy of sequential intravenous and oral ciprofloxacin in the treatment of moderate‐to‐severe urinary tract infections (UTI), and to identify risk factors for acquiring UTI caused by ciprofloxacin‐resistant organisms.

Materials and Methods: Using a prospective, open, single‐centre study design, hospitalized patients with a clinical diagnosis of moderately severe UTI were enrolled. After a minimum of 3 days of intravenous ciprofloxacin, patients were switched to oral therapy. Assessment for response and analysis of risk factors were performed at the end of therapy.

Results: Between December 1996 and November 1997, a total of 66 patients met the criteria for efficacy evaluation. Among the 55 patients with ciprofloxacin‐sensitive organisms, 51 patients (93%) were cured. Persisting infection was noted in three patients (5%) and one patient (2%) was re‐infected with a ciprofloxacin‐resistant organism. Of the organisms isolated, 14 (19%) were resistant to ciprofloxacin. The presence of prostatic obstruction (odds ratio 6.02, 95% confidence interval (CI) 1.28–28.30, P = 0.02) and recurrent UTI (odds ratio 8.63, 95% CI 1.81–41.17, P = 0.007) were independently associated with infections caused by ciprofloxacin‐resistant organisms. Adverse events were reported in 5 patients (8%) but no premature discontinuation or mortality was documented.

Conclusion: Sequential therapy with oral therapy after initial parenteral ciprofloxacin is safe and effective in the management of moderate‐to‐severe UTI in appropriately selected patients.