bluuebunny/crossref_metadata_2025 huggingface dataset:
Esomeprazole‐Based 1‐Week Triple Therapy Directed by Susceptibility Testing for Eradication of Helicobacter pylori Infection in Children
Authors: Arenz Tina , Antos David , Rüssmann Holger , Alberer Martin , Buderus Stefan , Kappler Matthias , Koletzko Sibylle
Published: July 2006

Background:

Poor compliance to therapy and antibiotic resistance are the main causes for failure of anti‐Helicobacter pylori therapy.

Objective:

To evaluate the effectiveness of esomeprazole‐based triple therapy directed by susceptibility testing.

Methods:

Symptomatic children with H. pylori infection, who underwent successful susceptibility testing and were colonized by no double‐resistant strain, received 1‐week triple therapy with esomeprazole, amoxicillin and either clarithromycin or metronidazole. Success of eradication was investigated by 13C‐urea breath test.

Results:

Fifty‐eight children (median age, 11.4 years; range, 2.2‐17.7 years; 81% immigrants) were included. Helicobacter pylori was resistant to clarithromycin in 5 (9%) and to metronidazole in 9 children (16%). Eradication was successful in 49 (92%) of 53 children receiving esomeprazole, amoxicillin and clarithromycin and in all 5 children treated with metronidazole instead of clarithromycin, resulting in an eradication rate of 93% (95% confidence interval, 83%‐98%, intention‐to‐treat analysis). All 4 treatment failures occurred in immigrants with language problems; 2 of them were obviously noncompliant.

Conclusion:

Esomeprazole‐based 1‐week triple therapy directed by susceptibility testing is highly effective for eradication of H. pylori infection in children.
Effect of Nissen Fundoplication on Gastric Motor and Sensory Functions
Authors: Mousa Hayat , Caniano Donna A. , Alhajj Maya , Gibson Laurie , Di Lorenzo Carlo , Binkowitz Larry
Published: July 2006

Objectives:

Bloating, abdominal pain, and early satiety have been reported in up to 30% of patients after Nissen fundoplication. We hypothesized that these postsurgical complications in children and young adults are linked to either the effects of surgery on gastric sensation, compliance or motor function or to preexisting physiological abnormalities.

Methods:

We prospectively evaluated the effect of Nissen fundoplication on gastric sensory and motor functions in 13 children with gastroesophageal reflux. Gastric barostat and mixed meal gastric emptying studies were performed before surgery in all patients and were repeated after surgery in 8 and 9 children, respectively.

Results:

Thirteen patients (median age, 7 years; range, 6 months to 18 years) underwent open Nissen (n = 6) or laparoscopic Nissen fundoplication (n = 7). After fundoplication, patients had significantly higher minimal distending pressure values (10 mm Hg vs 3 mm Hg pre‐Nissen, respectively; P < 0.001), reduced gastric compliance (slope values of 8.39 mm Hg vs 9.15 mm Hg, respectively, P < 0.001) and significantly higher pain scores (P < 0.001). Presurgery and postsurgery gastric emptying at 60, 90 and 120 minutes after feeding showed no significant changes.

Conclusions:

After Nissen fundoplication, children with gastroesophageal reflux manifest the following: (1) reduction in gastric compliance, (2) increase in minimal gastric distending pressure, (3) exacerbation of the sensations discomfort with gastric distension and (4) no effect on gastric emptying.
Resonance Raman characterization of archaeal and bacterial Rieske protein variants with modified hydrogen bond network around the [2Fe‐2S] center
Authors: Iwasaki Toshio , Kounosu Asako , Kolling Derrick R.J. , Lhee Sangmoon , Crofts Antony R. , Dikanov Sergei A. , Uchiyama Takuro , Kumasaka Takashi , Ishikawa Hiroyuki , Kono Miwa , Imai Takeo , Urushiyama Akio
Published: July 2006

The rate of quinol oxidation by cytochrome bc1/b6f complex is in part associated with the redox potential (Em) of its Rieske [2Fe‐2S] center, for which an approximate correlation with the number of hydrogen bonds to the cluster has been proposed. Here we report comparative resonance Raman (RR) characterization of bacterial and archaeal high‐potential Rieske proteins and their site‐directed variants with a modified hydrogen bond network around the cluster. Major differences among their RR spectra appear to be associated in part with the presence or absence of Tyr‐156 (in the Rhodobacter sphaeroides numbering) near one of the Cys ligands to the cluster. Elimination of the hydrogen bond between the terminal cysteinyl sulfur ligand (St) and Tyr‐Oη (as with the Y156W variant, which has a modified histidine Nε pKa,ox) induces a small structural bias of the geometry of the cluster and the surrounding protein in the normal coordinate system, and significantly affects some Fe‐Sb/t stretching vibrations. This is not observed in the case of the hydrogen bond between the bridging sulfide ligand (Sb) and Ser‐Oγ, which is weak and/or unfavorably oriented for extensive coupling with the Fe‐Sb/t stretching vibrations.
Nogo goes in the pure water: Solution structure of Nogo‐60 and design of the structured and buffer‐soluble Nogo‐54 for enhancing CNS regeneration
Authors: Li Minfen , Liu Jingxian , Song Jianxing
Published: July 2006

The inability to determine the structure of the buffer‐insoluble Nogo extracellular domain retarded further design of Nogo receptor (NgR) antagonists to treat CNS axonal injuries. Very surprisingly, we recently discovered that Nogo‐60 was soluble and structured in salt‐free water, thus allowing the determination of the first Nogo structure by heteronuclear NMR spectroscopy. Nogo‐60 adopts an unusual helical structure with the N‐ and C‐terminal helices connected by a long middle helix. While the N‐helix has no contact with the rest of the molecule, the C‐helix flips back to pack against the 20‐residue middle helix. This packing appears to trigger the formation of the stable Nogo‐60 structure because Nogo‐40 with the last helix truncated is unstructured. The Nogo‐60 structure offered us rationales for further design of the structured and buffer‐soluble Nogo‐54, which may be used as a novel NgR antagonist. Furthermore, our discovery may imply a general solution to solubilizing a category of buffer‐insoluble proteins for urgent structural investigations.
NANOG maintains self‐renewal of primate ES cells in the absence of a feeder layer
Authors: Yasuda Shin‐ya , Tsuneyoshi Norihiro , Sumi Tomoyuki , Hasegawa Kouichi , Tada Takashi , Nakatsuji Norio , Suemori Hirofumi
Published: July 2006

Nanog is a homeodomain transcription factor that is expressed specifically in undifferentiated embryonic stem (ES) cells and has been shown to be essential in the maintenance of pluripotency in mouse ES cells. To examine the function of NANOG in primate ES cells, we generated transgenic monkey ES cell lines expressing three‐ to seven‐fold higher levels of NANOG protein compared to wild‐type ES cells. These NANOG over‐expressing cell lines retained their undifferentiated state in the absence of a feeder layer, as shown by expression of undifferentiated ES cell markers such as alkaline phosphatase (ALP) and OCT‐4. We also demonstrated that in vitro differentiation of transgenic cell lines was mostly restricted to the ectodermal lineage, as examined by reverse transcriptase‐polymerase chain reaction (RT‐PCR). Knockdown experiments using NANOG small interfering (si) RNA resulted in induction of differentiation markers such as AFP, GATA4 and GATA6 for the endoderm and CDX2 for the trophectoderm. These results suggest that NANOG plays a crucial role in maintaining the pluripotent state of primate ES cells.
Ca2+‐independent phospholipase A2‐dependent sustained Rho‐kinase activation exhibits all‐or‐none response
Authors: Maeda Akio , Ozaki Yu‐ichi , Sivakumaran Sudhir , Akiyama Tetsuro , Urakubo Hidetoshi , Usami Ayako , Sato Miharu , Kaibuchi Kozo , Kuroda Shinya
Published: July 2006

Sustained contraction of cells depends on sustained Rho‐associated kinase (Rho‐kinase) activation. We developed a computational model of the Rho‐kinase pathway to understand the systems characteristics. Thrombin‐dependentin vivotransient responses of Rho activation and Ca2+increase could be reproducedin silico. Low and high thrombin stimulation induced transient and sustained phosphorylation, respectively, of myosin light chain (MLC) and myosin phosphatase targeting subunit 1 (MYPT1)in vivo. The transient phosphorylation of MLC and MYPT1 could be reproducedin silico, but their sustained phosphorylation could not. This discrepancy betweenin vivoandin silicoin the sustained responses downstream of Rho‐kinase indicates that a missing pathway(s) may be responsible for the sustained Rho‐kinase activation. We found, experimentally, that the sustained phosphorylation of MLC and MYPT1 exhibit all‐or‐none responses. Bromoenol lactone, a specific inhibitor of Ca2+‐independent phospholipase A2 (iPLA2), inhibited sustained phosphorylation of MLC and MYPT1, which indicates that sustained Rho‐kinase activation requires iPLA2 activity. Thus, the systems analysis of the Rho‐kinase pathway identified a novel iPLA2‐dependent mechanism of the sustained Rho‐kinase activation, which exhibits an all‐or‐none response.
Sustained activation of M‐Ras induced by nerve growth factor is essential for neuronal differentiation of PC12 cells
Authors: Sun Peng , Watanabe Haruko , Takano Kazunori , Yokoyama Takashi , Fujisawa Jun‐ichi , Endo Takeshi
Published: July 2006

Neuronal differentiation in PC12 cells induced by nerve growth factor (NGF) requires sustained activation of ERK/MAP kinase pathway (Raf–MEK–ERK cascade). Although classical Ras (H‐Ras, K‐Ras, and N‐Ras) activated by NGF signaling induces activation of ERK pathway, the activation is transient and not sufficient for PC12 cell differentiation. Instead, it has been widely accepted that NGF signaling‐mediated Rap1 activation causes sustained activation of ERK pathway. There has been no direct evidence, however, that Rap1 participates in neuronal differentiation. Here we show that NGF signaling induces sustained activation of M‐Ras and subsequent sustained activation of ERK pathway and the transcription factor CREB leading to PC12 cell differentiation. Exogenously expressed constitutively active mutant of M‐Ras caused neurite outgrowth in PC12 cells and activating phosphorylation of ERK, whereas activated Rap1 did not. Knockdown of endogenous M‐Ras by small interfering RNAs as well as the expression of a dominant–negative mutant of M‐Ras interfered with NGF‐induced neuritogenesis. Since MEK inhibitors prevented M‐Ras‐induced neurite outgrowth, ERK pathway participates in this differentiation pathway. Furthermore, M‐Ras brought about ERK pathway‐mediated activating phosphorylation of CREB and the CREB‐mediated transcription. In addition, a dominant–negative mutant of CREB inhibited M‐Ras‐induced neuritogenesis. Taken together, NGF‐induced PC12 cell differentiation requires M‐Ras–ERK pathway‐mediated activation of CREB. M‐Ras was predominantly expressed in the hippocampus and cerebellum of mouse brain and in the gray matter of the spinal cord. All these properties of M‐Ras were apparently indistinguishable from those of H‐Ras. However, NGF stimulation caused transient activation of classical Ras proteins but sustained activation of M‐Ras as well as sustained activating phosphorylation of ERK and CREB. Therefore, M‐Ras is essential for neuronal differentiation in PC12 cells by inducing sustained activation of ERK pathway.
Involvement of the Ser‐Glu‐Pro Motif in Ligand Species‐Dependent Desensitisation of the Rat Gonadotrophin‐Releasing Hormone Receptor
Authors: Song J. A. , Oh D. Y. , Moon J. S. , Geum D. , Kwon H. B. , Seong J. Y.
Published: July 2006

There are two forms of gonadotrophin‐releasing hormone (GnRH), GnRH‐I and GnRH‐II, in the vertebrate brain. Both GnRH‐I and GnRH‐II are thought to interact with the type‐I GnRH receptor (GnRHR). The present study attempted to demonstrate whether GnRH‐I and GnRH‐II induce differential desensitisation of GnRHR and to identify the motif involved. Time course inositol phosphate (IP) accumulation assay reveals that, in cells expressing the wild‐type rat GnRHR, GnRH‐I induced continuous increase in IP production, whereas GnRH‐II‐induced IP production rate at later time points (30–120 min after ligand treatment) became attenuated. However, in cells expressing the mutant receptor in which the Ser‐Glu‐Pro (SEP) motif in extracellular loop 3 was replaced by Pro‐Glu‐Val (PEV), IP accumulation rates at later time points were more decreased by GnRH‐I than GnRH‐II. Ca2+responses to repetitive GnRH applications reveal that GnRH‐II desensitised the wild‐type receptor faster than GnRH‐I, whereas the opposite situation was observed in the PEV mutant. In addition, cell surface loss of GFP‐tagged wild‐type receptor was more facilitated by GnRH‐II than GnRH‐I, whereas that of the GFP‐tagged PEV mutant receptor was more enhanced by GnRH‐I than GnRH‐II. The present study indicates that the SEP motif is potentially responsible for ligand species–dependent receptor desensitisation. Together, these results suggest that GnRH‐I and GnRH‐II may have different effects on mammalian type‐I GnRHR via modulation of desensitisation rates.
Young Adult‐Specific Hyperphagia in Diabetic Goto‐Kakizaki Rats is Associated with Leptin Resistance and Elevation of Neuropeptide Y mRNA in the Arcuate Nucleus
Authors: Maekawa F. , Fujiwara K. , Kohno D. , Kuramochi M. , Kurita H. , Yada T.
Published: July 2006

The present study aimed to examine whether hyperphagia, which is frequently observed in type 1 diabetic patients and model animals, also occurs in type 2 diabetic Goto‐Kakizaki (GK) rats and, if so, to explore underlying abnormalities in the hypothalamus. GK rats at postnatal weeks 6–12, compared to control Wistar rats, exhibited hyperphagia, hyperglycaemia, hyperleptinemia and increased visceral fat accumulation, whereas body weight was unaltered. The ability of leptin to suppress feeding was reduced in GK rats compared to Wistar rats of these ages. In GK rats, leptin‐induced phosphorylation of signal transducer and activator of transcription 3 was significantly reduced in the cells of the hypothalamic arcuate nucleus (ARC), but not of the ventromedial hypothalamus, whereas the mRNA level of functional leptin receptor was unaltered. By real‐time polymerase chain reaction and in situ hybridisation, mRNA levels of neuropeptide Y, but not pro‐opiomelanocortin and galanin‐like peptide, were significantly increased in the ARC of GK rats at 11 weeks, but not 26 weeks. Following i.c.v. injection of a NPY Y1 antagonist, 1229U91, the amount of food intake in GK rats was indistinguishable from that in Wistar rats, thus eliminating the hyperphagia of GK rats. These results demonstrate that young adult GK rats display hyperphagia in association with leptin resistance and increased NPY mRNA level in the ARC.
Treating acute mental illness in rural general hospitals: Necessity or choice?
Authors: Hungerford Catherine
Published: July 2006

Objective:  To identify reasons why rural general practitioners (GPs) treat a large proportion of patients with a primary psychiatric diagnosis in general beds of their local hospitals, and the barriers encountered when providing this treatment.

Design:  A postal questionnaire was developed and distributed to a sample of rural GPs, asking about the treatment of patients with an acute mental illness in their local hospital.

Results:  The majority of GPs agreed that they treat the acutely mentally ill in general beds of their local hospital due to lack of availability of, and inability to gain access to, mental health beds in the larger centres; and also to enable ongoing family involvement and continuity of care. Distance factors were identified as least significant. Barriers to providing care to this group of patients included a perceived lack of support by consultant psychiatrists, confidentiality issues, lack of community mental health workers to provide assistance, aggression levels of patients, inappropriate local hospital setting, and lack of confidence of GPs and general hospital nursing staff.

Conclusion:  Addressing these barriers is necessary if rural Australians are to receive a quality of care that is equal to that received by those located in metropolitan Australia. Continuing research in this area is crucial.
Co‐morbid drug and alcohol and mental health issues in a rural New South Wales Area Health Service
Authors: Hoolahan Bryan , Kelly Brian , Stain Helen J. , Killen Didi
Published: July 2006

Objective:  In 2003 the New South Wales (NSW) Centre for Rural and Remote Mental Health (CRRMH) conducted an analysis of co‐morbid drug and alcohol (D&A) and mental health issues for service providers and consumers in a rural NSW Area Health Service. This paper will discuss concerns raised by rural service providers and consumers regarding the care of people with co‐morbid D&A and mental health disorders.

Design:  Current literature on co‐morbidity was reviewed, and local area clinical data were examined to estimate the prevalence of D&A disorders within the mental health service. Focus groups were held with service providers and consumer support groups regarding strengths and gaps in service provision.

Setting:  A rural Area Health Service in NSW.

Participants:  Rural health and welfare service providers, consumers with co‐morbid D&A and mental health disorders.

Results:  Data for the rural area showed that 43% of inpatient and 20% of ambulatory mental health admissions had problem drinking or drug‐taking. Information gathered from the focus groups indicated a reasonable level of awareness of co‐morbidity, and change underway to better meet client needs; however, the results indicated a lack of formalised care coordination, unclear treatment pathways, and a lack of specialist care and resources.

Discussion:  Significant gaps in the provision of appropriate care for people with co‐morbid D&A and mental health disorders were identified. Allocation of service responsibly for these clients was unclear. It is recommended that D&A, mental health and primary care services collaborate to address the needs of clients so that a coordinated and systematic approach to co‐morbid care can be provided.
Statistical methods for analysis of repeated measures on maternal morbidity
Authors: Islam M. Ataharul , Chowdhury Rafiqul I. , Singh Karan P.
Published: July 2006

Objectives:  This paper applies statistical methods to identify factors associated with pregnancy‐related complications in rural Bangladesh. The results are examined in order to identify the factors that can help formulate policy for reducing pregnancy‐related morbidity.

Methods:  Two statistical methods are used in this study to analyse the repeated‐measures data on pregnancy‐related complications in rural Bangladesh. One method is based on the application of linear logistic regression at each follow up, and the results are compared to identify the potential risk factors. Then the generalised estimating equation (GEE) approach is used, and the results based on each follow up are compared with those obtained from the application of the GEE approach. The maternal morbidity data collected by the Bangladesh Institute of Research for Promotion of Essential and Reproductive Health and Technologies are used in this paper.

Results:  Economic status, visit for antenatal care, and histories of sexually transmitted disease, hypertension, heart disease and breathing problem are positively associated with the complications during pregnancy, while wanted pregnancy, household type, primary and secondary schooling, and five or more pregnancies are associated negatively with the response variable. Involvement with gainful employment shows a negative association by the first technique. The GEE approach failed to identify some important factors such as history of anaemia, previous pregnancy and gainful employment. However, duration of pregnancy appears to have an association with pregnancy complications, which was not found from the conditional model based on each follow up.

Conclusion:  It appears that unwanted pregnancies need to be reduced through a well‐organised and targeted family planning campaign for potential mothers of all ages in rural Bangladesh. Nutritional anaemia may cause various complications, and suggestions are given for reducing anaemia among pregnant women. In the rural areas of Bangladesh, first births usually occur at teenage. The first‐birth pregnancy among teenagers can be a source of severe complications. There can be special programs to address the need for delay in the first pregnancy of those who marry at an early age.
An outbreak of acute post‐streptococcal glomerulonephritis in remote Far North Queensland
Authors: Scrace Melania , Koko Karen
Published: July 2006

Background:  To observe and record an outbreak of acute post‐streptococcal glomerulonephritis (APSGN) in the Lockhart River community in 2005 and the steps taken by health workers to contain the epidemic.

Methods:  A descriptive study of cases of APSGN and children aged from 2 to 12 years involved in the screening program.

Setting:  A remote indigenous community in Far North Queensland.

Participants:  All children aged from 2 to 12 years in the Lockhart River community.

Results:  Eighty‐seven children were screened. And 46% were found to have infected scabies.

Conclusions:  There were 11 confirmed cases of APSGN over four months from February to May. Infected scabies was the main preceding finding in these children.
The value of structural features in tropical forest typology
Authors: WEBB L. J. , TRACEY J. G. , WILLIAMS W. T.
Published: July 2006

A pro forma is presented which is based on selected physiognomic–structural features of tropical forest vegetation. It was designed to facilitate collection of data by non‐botanists, and the occurrence of features was assessed either by presence/absence or on a four‐point scale.

Data were collected in a mixture of rain forests and sclerophyll forests in North Queensland and New Guinea, and analysed by an agglomerative polythetic method to provide a classification of sites.

The structural classification of the simple forests (regrowth rain forests, forests under extreme limiting conditions and eucalypt woodlands) was unsatisfactory, and floristic differentiation is necessary. However, the structural classification of the complex forests, and of mature forest vegetation over a wide environmental range, produced meaningful site‐groupings below the subformation level. The method of structural analysis is rapid and relatively inexpensive, and shows most promise in complex tropical vegetation for which floristic data are not usually available.
A comparison between two models for plant competition
Authors: TORSSELL B. W. R. , NICHOLLS A. O.
Published: July 2006

The differential equation of de Wit (1970) which predicts the growth of plant species in mixtures from their yield–density response in monocultures is compared with a simpler equation. This model is also based on the yield–density response of species grown in monocultures, but is static and predicts only the net result of plant competition during discrete time periods.

Data from successive harvests in yield–density experiments in monocultures of one grass and two legume species were fitted to both models and the relative reproductive rate and the relative replacement rate were calculated from model predictions. Predictions from our model agreed more closely with observations than predictions from the de Wit model. It is concluded that our model deserves further attention in the studies of population dynamics in mixtures when the final outcome of competition is the main interest.
Counting the flowers in the forest: combining two population estimates
Authors: LAUGHLIN ROGER
Published: July 2006

Isoneurothrips australis Bagnall lives in the flowers o, Eucalyptus trees. Knowing the mean number of thrips per flower, an estimate of the number of flowers was required so that the number of thrips in an isolated patch of scrub could be calculated. Flowers were sampled by two methods and the results compared and combined. The propriety of using probabilities higher than 0.05 for the calculation of confidence limits is discussed.
The effect of feral goats (Capra hircus L.) on the vegetation of Lord Howe Island
Authors: PICKARD JOHN
Published: July 2006

The conflicting but informative literature relating to goats on Lord Howe Island (31° 35’5 159° 05’ E) is reviewed. Observations made in 1970–72 indicate that the effects of goats are localized. Invasion of goat camps by naturalized plants is widespread. Changes attributable to goats are considered and one well documented example is discussed in detail. The effects of goats and pigs are compared. Goats occupy different but overlapping habitats from pigs. A total of 228 goats was shot in an extermination programme. Overall density is 0·17 goats/ha but local densities may vary from 0·56 goats/ha to 26·34 goats/ha. Rumen content analyses indicate that goats are both selective and individualistic feeders. Naturalized plants are eaten in the same proportion as they occur in the flora. The relationship between naturalized weeds and goats appears to be commensal.
On the developing use of modelling in insect ecology and pest management*
Authors: GEIER P. W. , CLARK L. R.
Published: July 2006

Systems modelling in insect ecology and management is undertaken for either descriptive or prescriptive purposes, and can be either general or specific in nature. Although recent achievements in general descriptive modelling are considerable, they do not contribute greatly in the analysis, synthesis and understanding of particular systems. Conditions governing progress in specific modelling are discussed mainly from Australian examples.

It is felt that a renewed emphasis should be placed on the inductive approach to the study of ecological systems. The cost of acquiring the necessary information is so great that, increasingly, empirical investigations will have to serve clearly defined, mission‐oriented goals. Consequently, in the immediate future, prescriptive modelling of particular systems for pest control may be the principal source of data and the main testing ground for generalizations.
A study of a subalpine woodland‐grassland boundary
Authors: MOORE R. M. , WILLIAMS J. D.
Published: July 2006

Reasons for the absence of trees on flat valley‐bottoms in the subalpine regions of south‐eastern Australia were studied at Seventeen Flat near Currango and other sites in the Snowy Mountains of New South Wales.

Temperature changes with height above terrain were measured at grassland and woodland sites by thermistors attached to a hydrogen‐filled balloon. The occurrence of nocturnal temperature inversions above grassland was established.

Minimum temperatures at 80 cm above ground were recorded for thirty‐one weeks at thirteen stations along a transect across the grassland and extending into the woodland on either side. Minima were lower and frequency of temperatures below—9°C were higher in grassland than in woodland.

Seedlings of subalpine woodland species and other eucalypts were planted at both grassland and woodland stations. At grassland stations seedlings of tree‐line species showed frost injury within a short time from planting and none survived two winters.

The death of planted trees at grassland stations, the high frequency of temperature inversions and the low minima recorded on grassland compared with woodland suggest that temperature is a primary cause of the absence of trees in grasslands below subalpine woodlands.
An altitudinal transect in rain forest in the Barrington Tops area, New South Wales
Authors: TURNER J. C.
Published: July 2006

On the southern slopes of Barrington Tops, N.S.W., an exploratory study was made of altitudinal gradation between subantarctic or temperate rain forest (at higher elevations) and subtropical rain forest. The former is dominated by Nothofagus moorei while the latter has no clear dominants and is floristically and structurally more complex.

To sample the ecotone, a single 800 m line containing thirty‐seven 200 m2 circular plots was placed on a S.S.W.‐facing slope between altitudes of 800 and 1040 m. The inclinations of the surfaces of individual plots ranged from 5° to 35°. Measurement and analysis were restricted to trees (including coppices), vines and tree ferns, with emphasis on density, basal area and importance values.

Vertical extent of the ecotone is determined rather arbitrarily as being about 90 m. Floristically, the ecotone has elements both of a mosaic and of a gradual mix of species of the upper and lower rain forests. Its areal complexity is increased by the presence of small‐scale topographic features; the typical step‐and‐terrace sequence resulting from dissection of multiple basalt flows. There is a gradual dropping out of species of the subtropical rain forest upwards along the whole transect. The rate of drop‐out is greatest at the bases of any steep steps on the slope. Certain species, notably Doryphora sassafras, are shared by the two kinds of rain forest. In physiognomy too, there is further evidence for continuity: the size and density of vines as well as leaf sizes of trees and vines decrease gradually upwards. In terms of Webb's system of structural types of Australian rain forest there is sustained gradation from notophyll‐microphyll vinefern forest (at the bottom) to microphyll fern forest.

There is strong evidence that Nothofagus moorei is not regenerating within most of the ecotone. Speculation is offered about ecotonal dynamics in terms of climatic change, fire frequency and the mode of reproduction of N. moorei.
Growth and competition in annual legume—perennial grass pasture in a dry monsoonal climate
Authors: IVE J. R.
Published: July 2006

The seasonal growth characteristics of a perennial (sabi grass (Urochloa mosambicensis))‐annual (Townsville stylo (Stylosanthes humilis)) pasture ecosystem in the dry monsoonal region of norther Australia are described. The phases during which the botanical composition of the ecosystem may change are dry season plant survival, germination, establishment, growth and propagation. A conceptual model with general applicability for a pasture of perennial and annual species is presented and the inter‐relationships between the identified phases are indicated.

For the example studied, there was a large decline in the proportion of the annual legume in the establishment phase, due to competition for restricted soil moisture. This explains the trend to grass dominance observed in sabi grass‐Townsville stylo swards, and is considered to apply generally in a perennial‐annual pasture in a dry monsoonal environment.

Two distinct environmental periods occurred during the season and were reflected in the observed growth characteristics. During the first, the growth rate of Townsville stylo was slow and plant density fluctuated sharply. The growth rate of sabi grass also fluctuated sharply due to high temperature and radiation, and variable but limiting soil moisture. In the second period temperatures were lower and soil moisture was higher. During this period growth rate of sabi grass and tiller production declined but both the plant density of sabi grass and the growth rate of Townsville stylo increased.

As sabi grass has a high initial growth rate and nitrogen and phosphorus contents which are nutritionally acceptable during the transition between the dry and wet seasons, monospecific sabi grass swards are suggested for grazing during this period.
Generic plant assemblages in the highland forests of Papua New Guinea
Authors: WALKER D. , GUPPY J. C.
Published: July 2006

Virtually complete tree lists from seventy‐eight sites in four regions above 1900 in a.s.l. in Papua New Guinea are analysed numerically and the results compared with classifications already in use. A major floristic break occurs between 2800 m and 3000 w a.s.l. The Upper Mountain Forest above this is tentatively divided into four nodes, the altitudinally lowest (< 3400 m) being pliysiognomically similar to the forest below. The Lower Mountain Forest below the major break has two nodes, one of which may be an assemblage of variously depauperate and less stable derivatives of the other: they are not altitudinally distinct.
An improved numerical method for the analysis of a floristic pasture survey
Authors: WILLIAMS W. T. , GILLARD P. , EDYE L.A.
Published: July 2006

A classical ecologist is usually equally interested in groups of sites and groups of species, so that symmetrical numerical models are appropriate for the elucidation of floristic pattern. It is suggested that an agronomist is primarily interested in the pattern of site‐ (usually paddock‐) groups, and is only interested in those species‐groups whose members are present in sufficient abundance to be quickly recognizable, and which serve to discriminate clearly between the site‐groups. An‘asymmetric inverse’model is defined for the purpose of extracting species‐groups of this type, which can be combined with a site classification into a two‐way table. The method is applied to a floristic survey carried out at the end of a grazing experiment, and is shown to produce meaningful and profitable results.
Self‐thinning in Trifolium subterraneum not affected by cultivar shape
Authors: WESTOBY MARK
Published: July 2006

As it was thought that self‐thinning in crowded plant populations might be influenced by the shape of the plants involved, self‐thinning was examined in five cultivars of Trifolium subterraneum. The height of these cultivars is fixed after early growth, being determined mainly by petiole length which itself varies between cultivars. No detectable differences between cultivars were found, and it is argued that only wore considerable differences in shape than those reported here would have detectable effects.

When plants can only grow radially but not in height, it is to be expected that log‐log self‐thinning curves would have a slope of ‐1, but these Trifolium populations had the – 3/2 slope usually found for species which exhibit continuous growth in height. This finding remains unexplained.
Soil water regimes and water extraction patterns under two semi‐arid shrub (Atriplex spp.) communities
Authors: SHARMA M. L.
Published: July 2006

Soil water regimes and water extraction patterns estimated over a period of two years are described for two plantation communities of semi‐arid shrubs, Atriplex vesicaria Hew. ex Benth. and A. nummularia Lindl., growing on the same soil type under identical climatological conditions near Deniliquin, New South Wales.

In spite of poor water flow properties of the soil, surface run‐off was negligible.About 90% of the extractable water was stored in the top (45 cm) soil layer. Both species withstood exceedingly low water potentials, although A, vesicaria reduced soil water to a much lower water potential than did A. nummularia. Water potentials at depths below 60 cm were always – 15 bars and remained constant. Water extracted beyond –15 bars amounted to 41% more than the water available within conventionally accepted water potential limits (between –0.3 to – 15 bars). During Slimmer, the plant water potential of A. vesicaria fell to much lower values than that of A. nummularia. Relationships between relative leaf water content and plant water potential differed between the two species, and the suggestion is made that at low plant water potential, leaf targidity of A. vesicaria would be higher, and thus this species would have a higher tolerance to desiccation.

On a yearly, half‐yearly and even a quarterly basis, evapotranspiration (FT) of the two communities did not differ. Fortnightly FT rates were similar during winter but during early summer, the initial ET rate of A. vesicaria was higher than that of A. nummularia; A, nummularia can therefore conserve water for later use. These differences in water extraction patterns and evapotranspiration were associated with differential rooting characteristics and probably differential stomatal functioning. The relationships between fortnightly ET/FO (ratio of actual evapotranspiration to that from a Class A pan) and profile water content, for both communities, were linear but different.
The effects of temperature on germination and early growth of three plant species indigenous to Central Australia
Authors: ROSS M. A.
Published: July 2006

The temperature responses of the perennial grass Eragrostis eriopoda Benth., an all‐season annual grass (Enneapogon polyphyllus Domin.) and a cool‐season annual forb (Lepidium muelleri‐ferdinandi Thell.) were studied in two experiments, one during germination and the other during the establishment phase.

In the first experiment, extreme differences in the response of germination to temperature occurred between species. The optimum was 42°C for Eragrostis and 15 to 21° C for Enneapogon and Lepidium although Enneapogon tolerated higher temperatures than did Lepidium. The effect of temperature on speed of germination is discussed.

In the second experiment, seedlings were assigned to six day/night temperature regimes ranging from 24/16 C to 45/31 C for three weeks in a phytotron. Both grasses responded positively to temperatures tip to 30/22°C with little further change up to 45/37° C, while Lepidium died at temperatures greater than 30/22° C.

The experimentally determined response to temperature reflected field observations of seasonal establishment patterns for each species. The ecological significance of the results is discussed.
Comparisons of habitat structure and plant, arthropod and bird diversity between mainland and island sites near Perth, Western Australia
Authors: ABBOTT IAN
Published: July 2006

Detailed estimations of habitat structure, plant species diversity and diversity of arthropods were made at six 4.0 ha sites, two on mainland Western Australia near Perth and four on adjacent islands. The number of resident passerine bird species was also recorded at each site. Plant species diversity, and horizontal foliage diversity (=patchiness) varied only slightly between sites. There were significant positive correlations between arthropod Order diversity and bird diversity, and between vertical foliage diversity and bird diversity.

In both Acacia and dune scrub, the Rottnest Island sites had more individuals of arthropods than the mainland sites but these belonged to fewer Orders. Numerical imbalance between arthropod Orders on Rottnest Island probably results from diminution of predators (passerine birds) there. As the actual number of arthropods is higher on the islands, the absence of so many species of passerine birds may result from other factors (ecological and historical).
The effects of a severe drought on the morphology of the adrenal glands and other indices of health in the red kangaroo Megaleia rufa (Desmarest) in north‐western New South Wales*
Authors: MYERS K. , BAILEY P. J. , DUDZIŃSKI M. L.
Published: July 2006

Drought adversely affects health and reproduction in red kangaroos (Megaleia rufa) (Desmarest). There is a significant drop in body weight in adult kangaroos, and growth rates of pouch young are depressed. In adult males both lobes of the pituitary gland decrease in size. All zones in the adrenal glands become smaller and lipid stores increase. In adult females the posterior lobe of the pituitary increases in size and, although all zones in the adrenal glands shrink the evidence suggests continued stimulation of the Zonae fasciculata and glomerulosa. The decrease in size of the adrenal glands is accompanied by cortical folding and nodulation and other structural changes.

Growth curves of pouch young are shown to fit the Johnson‐Schumacher curve Y = A * exp [‐b/(x + k)].

The data substantiate the findings of earlier workers but suggest that anoestrous female red kangaroos suckling small young may be better adapted to withstand drought than males.
Time resources and population dynamics in insects
Authors: KITCHING R. L.
Published: July 2006

An account is given of the way the temperature‐mediated processes of development and locomotor activity in insects interact with the availability of essential resources to reduce lifetime fecundity below the potential predicted from laboratory performance. Current work on the sheep blowfly, Lucilia cuprina, is used to illustrate the points made wherever possible.

Brief reviews of the ecologically important relationships between rate of development and temperature and level of activity and temperature are presented. The ways in which such laboratory‐derived relationships may be applied in the interpretation of field results are described and discussed. The notions of time as a resource and of protein‐food, mates and oviposition sites as limiting resources are presented and these provide the basis of a time/resource/fecundity mechanism limiting reproductive performance during the life‐time of a female insect. Field and laboratory data are used to show the potentiality of such a mechanism for reducing life‐time fecundity in the sheep‐blowfly.
The population dynamics of the bushfly: the elucidation of population events in the field
Authors: HUGHES R.D.
Published: July 2006

At three well differentiated sites and over three seasons bushfly abundance at first increased rapidly, but then stabilized or fell slowly through the apparently favourable periods of summer and early autumn, before a rapid end of season decline. Analysis of the characteristics of flies taken regularly in a sampling programme allowed the sequence of population events involved to be elucidated. Adult flies immigrated in spring. They and their first progeny were comparatively large but in the subsequent locally bred generations a progressive decrease in fly size was associated with a gradual decline in the levels of natality and a gradual increase in the levels of mortality. Between site differences could be traced to variation in the balance of these changes. Climate may have a large role in the population dynamics of the bushfly but its effects are largely indirect. Fuller understanding of the bushfly life system requires some way of synthesizing the effects and interactions between the many factors involved.
The capacity for increase at a low temperature of several Australian populations of Sitophilus oryzae (L.)
Authors: EVANS D.E.
Published: July 2006

The capacity for increase (Ic) of one laboratory and seven field populations of young adult S. oryzae from different sites in Australia was determined over a thirty‐week period at 15°C, a supposedly marginal temperature, in wheat of 14% moisture content.

The average value of Ic was 0.0838 ± 0.0017 and the populations comprised three significantly different groups. Variations in the net rate of increase per generation (R0) which averaged 34.7±1.71, had a major effect on the value of rc whereas variation in the cohort generation time (Tc), which averaged 41.6±.23 weeks had only a minor effect. The survivorship of adults of the populations did not differ significantly and 93% of females were alive after thirty weeks. Estimates of rc based on a fifteen‐week period and on an amended value of Tc differed little from those over thirty weeks.

The capacity for increase at 15°C of a given population was found to be correlated with its fertility at 27°C and with its body‐weight rather than with its cold‐tolerance, as evidenced by chill‐coma temperature, or with its previous temperature‐history.

The temperature experienced by the immature stages of weevils had a profound effect on rc in that weevils reared at 15 and 27°C had respective values of 0.0350 and 0.0707 when subsequently cultured at 15°C.

Because all observed values of rc were higher than expected, possible errors in method were considered. An alternative estimate of R0 agreed closely with that observed and indicated that only 17% of the immature stages survived at 15°C. Metabolic heating due to the higher than expected population density shortened the duration of the immature stages by 7% but did not affect their survival.
The capacity for increase at a low temperature of some Australian populations of the granary weevil, Sitophilus granarius (L.)
Authors: EVANS D. E.
Published: July 2006

The capacity for increase (rc) of one laboratory and seven field populations of young adult S. granarius from different sites in Australia was determined over thirty‐two weeks at 15°C in wheat of 14% moisture content.

The mean value of rc was 0.0704 ±0.0016 and the populations differed significantly with respect to this parameter. Variation in the net reproductive rate (R0), which averaged 25.4± 1.29, had a greater effect on the value of Ic than did variation in the cohort generation time (Tc), which averaged 45.7±0.37 weeks. The populations did not differ significantly in terms of adult survivorship and 94% of females were still alive at thirty‐two weeks. The maximum rate of oviposition, about ten eggs per female per week, was achieved in the eighteen‐twenty week age‐interval. About 41% of the immature stages survived to adulthood. Estimates of rc over a twenty‐four week period were only slightly lower than those over thirty‐two weeks.

The capacity for increase at 15°C of a given population was shown to be correlated with its fertility at 29°C, an optimal temperature, and with its body weight rather than with its cold tolerance, as indicated by its chill‐coma temperature, or its previous temperature‐history.

The temperature experienced by the immature stages had a marked influence on rc in that weevils reared at 15°C and 27°C had respective values of 0.0654 and 0.0786 when subsequently held at 15°C.

The differences in the survivorship and fertility of S. granarius and S. oryzae (L.) when both species were reared at 15°C are considered.
The effects of temperature and photoperiod on the morphology of the egg‐pod of the Australian plague locust (Chortoicetes terminifera Walker, Orthoptera: Acrididae)
Authors: WARDHAUGH K. G.
Published: July 2006

Chortoicetes terminifera can detect absolute differences of both temperature and photo‐period, as well as the directional change of these parameters. Insects subjected to long‐day conditions, or to an increase in photo‐period during development lay long straight pods, whereas those subjected to short days or to a decrease in photoperiod during development lay short pods, which are usually curved and/or laid obliquely. Temperature does not affect oviposition behaviour at long photoperiod, but at medium and short photoperiod, high temperature or an increase in temperature promotes the production of long pods, whereas low temperature or a decrease in temperature stimulates the production of short pods. When temperature and photoperiod change in opposite directions, the effects of photoperiod override those of temperature. The significance of these findings is discussed in relation to egg development and survival.
The heath‐savannah problem: the effect of fertilizer on sand‐heath vegetation of North Stradbroke Island, Queensland
Authors: SPECHT R. L. , CONNOR D.J. , CLIFFORD H. T.
Published: July 2006

A balanced fertilizer treatment ‐ equivalent to that optimal for pasture development on the infertile sandy soils of the Coastal Lowlands of south‐eastern Queensland ‐ was applied to a heathland stand on North Stradbroke Island in 1968, 3 years after the vegetation had been razed by bushfire. The fertilized and control plots were examined in detail in 1968 (before application of fertilizer), in 1969 and in 1976.

Eight years after fertilizer treatment the heath species have declined in density and/or biomass. The native grass, Themeda australis, responded to fertilizer and is expanding into gaps as the heath species die. A few composites and grasses are invading the fertilized plots.