bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of Mortality in the Stockholm Ischaemic Heart Disease Secondary Prevention Study by Combined Treatment with Clofibrate and Nicotinic Acid
Authors: Carlson Lars A. , ROSENHAMER GUNNAR
Published: August 2010

Consecutive survivors of a myocardial infarction from the Southern Hospital, below 70 years of age, were randomized into a Control group (n=276) and a Treatment group (n=279). The latter was openly prescribed the combination of clofibrate and nicotinic acid for serum lipid lowering. Each patient should remain in the study for 5 years and be seen regularly every 4 months at a special IHD outpatient clinic within the hospital. The concentration of serum cholesterol and triglyceride was lowered by 13% and 19%, respectively, in the Treatment group compared to the Control group. Total mortality was 82 cases in the Control group and 61 in the Treatment group, a 26% reduction (p<0.05). For patients above 60 years of age in the Treatment group the reduction in mortality was 28% (p<0.05). IHD mortality was reduced by 36% (p<0.01)in the Treatment group compared to the Control group. The beneficial effect of the serum lipid lowering treatment was related to the serum triglyceride concentration in two ways. First, it only occurred in patients with a triglyceride level >1.5 mmol/l (n=216). Secondly, it was most pronounced in the 44% of the treated patients who had a lowering of the serum triglyceride concentration by 30% or more, and in this subgroup the reduction of IHD mortality was 60% (p<0.01). For serum cholesterol there were no such relations. The difference between serum triglycerides and cholesterol concerning these relations to the treatment outcome may be due to the fact that hypertriglyceridaemia was the most common hyperlipidaemia among our patients, occurring in 50%, while hypercholesterolaemia only occurred in 13 %. Caution should be exercised in the interpretation of the results as the trial was not blind. However, the fact that the decrease in IHD deaths was directly related to the degree of serum triglyceride lowering indicates that it was the drug effect on serum lipids that was reponsible for the beneficial effect of the treatment.
Renal Hemodynamics and Blood Pressure Control in Patients with Pyelonephritic Renal Scarring
Authors: JACOBSON STEFAN H. , LINS LARS‐ERIC
Published: August 2010

ABSTRACT Pyelonephritic renal scarring is a common cause of renal failure and hypertension. We studied glomerular filtration rate (GFR), renal plasma flow (RPF), filtration fraction (FF), total renal area (TRA), systolic (SBP) and diastolic (DBP) blood pressure in 22 female patients with verified renal scarring and a history of febrile urinary tract infection (UTI) and in 9 healthy age‐matched women with normal urograms and no history of symptomatic UTI. The patients with renal scarring had significantly lower GFR, smaller TRA and higher SBP than the healthy controls, but not significantly different RPF or FF. A decrease in GFR and RPF was associated with higher SBP and DBP in the patients with renal scarring. RPF/TRA, representing an approximation of the perfusion of renal tissue and GFR/TRA, were similar in patients with renal scarring and healthy controls. A reduction of renal parenchyma was accompanied by a proportional decrease in GFR and RPF, resulting in unchanged FF. These findings do not support the concept of hyperfiltration as a main cause of renal insufficiency in patients with pyelonephritic renal scarring. An increase in FF and a decrease in GFR/TRA and RPF/TRA was associated with higher DBP and a decrease in GFR/TRA and RPF/TRA with an increase in the urinary albumin excretion. We conclude that renal hemodynamics play an important part in the blood pressure control of patients with renal scarring and that in these patients with various degrees of renal failure there was no evidence of hyperfiltration or hyperperfusion by remnant glomeruli.
Atrial Natriuretic Peptide, Angiotensin II and Aldosterone in Plasma in Chronic Glomerulonephritis during Basal Conditions and during Exercise
Authors: DANIELSEN HENNING , PEDERSEN ERLING B.
Published: August 2010

ABSTRACT Atrial natriuretic peptide (ANP), angiotensin II (AII) and aldosterone (Aldo) in plasma were determined at supine rest in 16 normotensive and 9 hypertensive patients with chronic glomerulonephritis and in 18 control subjects (Study 1). In addition, 12 of the normotensive, 7 of the hypertensive patients and 11 of the control subjects were studied with the same parameters after an exercise test (Study 2). Study 1 showed that supine ANP, AII and Aldo did not differ significantly between the groups. In Study 2, ANP increased after exercise in the normotensive patients (8.4 vs. 11.4 pmol/1 (median), p<0.05) and control subjects (7.6 vs. 9.3 pmol/1, p<0.02) but not in the hypertensives (7.6 vs. 7.9 pmol/1, p>0.10), and after exercise ANP was increased in the normotensive patients compared with the controls (p<0.02). After exercise, an enhanced increase of Aldo was found in the hypertensives but not in the normotensive patients compared with the controls, whereas the increase of AII did not differ significantly between the groups. It is concluded that patients with chronic glomerulonephritis and relatively well preserved renal function do not have major abnormalities of ANP at rest or during exercise. In the normotensive patients, however, ANP increased to a higher level than in the controls, but the difference was small and further studies are needed to define the role of ANP in blood pressure regulation of early stage chronic glomerulonephritis.
Melatonin Secretion Related to Side‐effects of β‐Blockers from the Central Nervous System
Authors: BRISMAR KERSTIN , HYLANDER BRITTA , ELIASSON KEITH , RÖSSNER STEPHAN , WETTERBERG LENNART
Published: August 2010

ABSTRACT In two studies of hypertensive patients the relationship between β‐blocker‐induced CNS side‐effects and the nightly urinary secretion of melatonin was analysed. In one group (n=10) placebo, atenolol (mean dose 86 mg/day) or propranolol (mean dose 305 mg/day) were given in a double‐blind, randomised design. In the other (n = 13) 100–400 mg metoprolol was given daily (mean dose 197 mg). After 4 weeks of treatment all β‐blockers reduced melatonin excretion, but the effect was significant only for metoprolol. Sleep disturbance records revealed more disturbed nights in the metoprolol group compared with the propranolol and the atenolol groups, even when the difference in age between the groups was controlled for. In the metoprolol group a significant relationship (p<0.05) was found between the fall in melatonin and the percentage of disturbed nights. Severe CNS side‐effects, such as nightmares, occurred only in patients treated with metoprolol (21%), which in all cases were accompanied by low levels of melatonin. Our data suggest that the CNS side‐effects during β‐blockade are related to a reduction of melatonin levels.
Social Isolation and Mortality in Ischemic Heart Disease
Authors: ORTH‐GOMÉR KRISTINA , UNDÉN ANNA‐LENA , EDWARDS MARY‐ELLEN
Published: August 2010

ABSTRACT The effects of psychosocial and clinical factors on mortality in ischemic heart disease (IHD) were examined in a 10‐year follow‐up of 150 middle‐aged men. Three groups of men were included: men with clinically manifest IHD, men with risk factors and healthy men. Psychosocial factors were assessed by means of standardized questionnaires. They comprised educational level, social class, marital status and a comprehensive assessment of the daily rounds of life of these men. Furthermore, a subjective rating of the own general health status was obtained. The clinical investigation included a standard physical examination, fasting serum lipids, glucose and urate, a frontal and sagittal chest X‐ray and a 24‐hour ambulatory ECG monitoring. During follow‐up 37 men died, 20 of them from IHD. Non‐survivors were descriminated from survivors by the following factors: older age, lower education, lower social class, higher systolic blood pressure, increased ventricular irritability and cardiac enlargement. Furthermore, a relative social isolation as indicated by a low social activity level and a poor self‐rated general health status was characteristic of non‐survivors. In multivariate analyses three factors emerged as the equally strong predictors of mortality, both from all causes and from IHD: social isolation, a poor self‐rated health status and ventricular irritability. The psychosocial mortality predictors were independent of and of similar strength as the clinical predictors.
QRS Amplitudes, QTc Intervals and ECG Abnormalities in Pheochromocytoma Patients before, during and after Treatment
Authors: STENSTRÖM GUNNAR , SWEDBERG KARL
Published: August 2010

ABSTRACT QRS amplitudes (S1 + R5), Minnesota Code ECG abnormalities and QTc intervals were analyzed in ECGs from 31 pheochromocytoma patients on admission to hospital, after 17±7.2 (SD) days of preoperative phenoxybenzamine therapy in a dosage of 148± 45.0 (SD) mg/day and after a mean postoperative follow‐up of 6 years. QRS voltage decreased significantly from 3.37± 1.48 on admission, to 2.26±0.69 mV at postoperative follow‐up (p<0.001). The prevalence of total Minnesota Code changes increased or was unchanged on the different occasions. Severe to moderate changes, however, became less prevalent, while mild changes increased. The QTc interval was 0.44±0.04 s on admission and 0.41±0.02 s at follow‐up (p<0.01). No significant differences were observed during treatment with phenoxybenzamine. Pathological ECGs are common findings in patients with pheochromocytoma and significant improvements occur after surgery. Significant effects of phenoxybenzamine therapy were only found in patients with sustained hypertension.
Low Specificity of the 125I‐Fibrinogen Uptake Test for the Diagnosis of Deep Vein Thrombosis in Patients with Erysipelas of the Leg
Authors: LINDBLAD BENGT , WALLMARK EWA , BERGQVIST DAVID , CRONBERG STIG
Published: August 2010

Abstract. The 125I‐fibrinogen test was evaluated as a diagnostic tool for deep vein thrombosis in patients with erysipelas. In the investigated group of 43 patients, several showed an increased uptake that could not be verified by subsequent phlebography. The false positive test may have been caused by the local inflammatory process. The 125I‐fibrinogen test seems to be too unspecific to be used for diagnosing deep vein thrombosis in this patient group.
Magnesium, Potassium and Zinc Deficiency in Subjects with Type II Diabetes Mellitus
Authors: SJÖGREN ANDERS , FLORÉN CLAES‐HENRIK , NILSSON ÅKE
Published: August 2010

Abstract. The concentrations of magnesium, potassium and zinc were determined in plasma, erythrocytes, muscle biopsies, and in urine collected during 24 hours, in 18 subjects with type II diabetes mellitus (DM). Magnesium was also determined in mononuclear cells. The results were compared with those in 35 (magnesium and potassium analyses) or 26 (zinc analyses) healthy controls. Subjects with type II DM had lower concentrations of magnesium (3.79±0.32 vs. 4.29±0.22 mmol/100 g FFDS), potassium (40.5±5.17 vs. 46.1±3.81 mmol/100 g FFDS) and zinc (231±29 vs. 247±23 ng/mg FFDS) in skeletal muscle. Furthermore, the urinary excretions of magnesium and zinc were higher, as compared with those in healthy controls (5.00±2.68 vs. 3.62±1.47 mmol/24 hours, and 683±285 vs. 326±205 μg/24 hours, respectively). The contents of magnesium, potassium and zinc plasma did not correlate with the corresponding concentrations in skeletal muscle or circulating blood cells, as investigated in healthy controls, diabetics and in all subjects together, implying that the plasma concentrations are not useful in the assessment of electrolyte status. Hence, deficiency of electrolytes frequently occurs, and should be looked for, in subjects with type II DM.
Immunological Studies of Patients with Down's Syndrome
Authors: KANAVIN ØIVIND , SCOTT HELGE , FAUSA OLAV , EK JOHAN , GAARDER PER I. , BRANDTZAEG PER
Published: August 2010

Abstract. Recurrent diarrhoea and weight loss in many adult patients with Down's syndrome (DS), initiated a search for malabsorption based on determination of serum IgG and IgA antibody levels to dietary antigens. The results were compared with measurements of autoantibodies and serum zinc levels. DS patients had increased IgG and IgA activities to gluten proteins, casein and ovalbumin compared with an age‐ and sex‐matched group of other mentally retarded patients in the same institution. Intestinal biopsy was performed in six of the 38 patients; one had total and one partial villous atrophy. Serum zinc was significantly lower in DS patients (median 14.7 μmol/l, range 5.5–20 μmol/l) than in the controls (median 16.4 μmol/l, range 12.7–19.5 μmol/l). DS patients with increased IgA activity to gluten weighed less and had lower concentrations of zinc in serum than DS patients with normal IgA activity. Twenty‐eight per cent of the DS patients had autoantibodies to the thyroid gland. Our results suggest intestinal malfunction in DS, perhaps related to a defect of immune regulation caused by reduced levels of zinc in serum.
Gilbert's Syndrome—Does It Exist?
Authors: OLSSON ROLF , BLIDING ÅKE , JAGENBURG RUDOLF , LAPIDUS LEIF , LARSSON BO , SVÄRDSUDD KURT , WITTBOLDT SVEN
Published: August 2010

Abstract. Liver function tests and prevalence of different symptoms generally said to occur in Gilbert's syndrome were analysed in male conscripts and in male and female participants in two cross‐sectional population studies in Göteborg, in total 2395 subjects. The serum bilirubin levels showed a skew distribution without bimodality. We observed no tendency to higher prevalence of symptoms in subjects with high serum bilirubin levels, but normal alkaline phosphatase and aminotransferase values compared to subjects with normal bilirubin. The findings contradict the existence of a disease entity named “Gilbert's syndrome”.
Atrioventricular Valve Plane Displacement in Healthy Persons
Authors: HÖGLUND CHRISTER , ALAM MAHBUBUL , THORSTRAND CURT
Published: August 2010

Abstract. A method of measuring the displacement of the atrioventricular (AV) of the left ventricle plane during the cardiac cycle in 71 healthy persons is described. An echocardiographic equipment with two cursors was used. Measurements were performed from four sites in the AV plane situated about 90 degrees apart and corresponding to the septal, anterior, lateral and posterior myocardial walls. The mean displacement during systole was 16 mm towards the apex. There was no significant difference in the recordings from the four sites. The study population was divided into three groups with mean ages 28, 42 and 60 years (group I, II and III). The displacement was significantly smaller in group III compared with groups I and II. Fractional shortening, however, could not demonstrate such a difference. The determination of displacement of the AV plane may imply the introduction of a new and simple method in assessment of left ventricular function.
Comparative landscape genetics of two pond‐breeding amphibian species in a highly modified agricultural landscape
Authors: GOLDBERG C. S. , WAITS L. P.
Published: August 2010

Evaluating fine‐scale population structure of multiple species in the same landscape increases our ability to identify common patterns as well as discern ecological differences among species’ landscape genetic relationships. In the Palouse bioregion of northern Idaho, USA, 99% of the native prairie has been converted to nonirrigated agriculture and exotic grasslands. Columbia spotted frogs (Rana luteiventris) and long‐toed salamanders (Ambystoma macrodactylum) in this area breed almost entirely in artificial ponds on private land. We used genetic distances (FST and Dc) derived from eight microsatellite loci in 783 samples to evaluate the relationships among sympatric breeding populations (N = 20 and 26) of these species in a 213‐km2 landscape. Both species showed a pattern of isolation by distance that was not improved when distance was measured along drainages instead of topographically corrected straight lines (P < 0.01). After testing for autocorrelation among genetic distances, we used an information theoretic approach to model landscape resistance based on slope, soil type, solar insolation, and land cover, and multi‐model inference to rank the resistance of landscape surfaces to dispersal (represented by genetic distance). For both species, urban and rural developed land cover provided the highest landscape resistances. Resistance values for long‐toed salamanders followed a moisture gradient where forest provided the least resistance, while agriculture and shrub/clearcut provided the least resistance for Columbia spotted frogs. Comparative landscape genetics can be a powerful tool for detecting similarities and differences between codistributed species, and resulting models can be used to predict species‐specific responses to landscape change.
Back to nature: ecological genomics of loblolly pine (Pinus taeda, Pinaceae)
Authors: ECKERT ANDREW J. , BOWER ANDREW D. , GONZÁLEZ‐MARTÍNEZ SANTIAGO C. , WEGRZYN JILL L. , COOP GRAHAM , NEALE DAVID B.
Published: August 2010

Genetic variation is often arrayed in latitudinal or altitudinal clines, reflecting either adaptation along environmental gradients, migratory routes, or both. For forest trees, climate is one of the most important drivers of adaptive phenotypic traits. Correlations of single and multilocus genotypes with environmental gradients have been identified for a variety of forest trees. These correlations are interpreted normally as evidence of natural selection. Here, we use a genome‐wide dataset of single nucleotide polymorphisms (SNPs) typed from 1730 loci in 682 loblolly pine (Pinus taedaL.) trees sampled from 54 local populations covering the full‐range of the species to examine allelic correlations to five multivariate measures of climate. Applications of a Bayesian generalized linear mixed model, where the climate variable was a fixed effect and an estimated variance–covariance matrix controlled random effects due to shared population history, identified several well‐supported SNPs associating to principal components corresponding to geography, temperature, growing degree‐days, precipitation and aridity. Functional annotation of those genes with putative orthologs in Arabidopsis revealed a diverse set of abiotic stress response genes ranging from transmembrane proteins to proteins involved in sugar metabolism. Many of these SNPs also had large allele frequency differences among populations (FST = 0.10–0.35). These results illustrate a first step towards a ecosystem perspective of population genomics for non‐model organisms, but also highlight the need for further integration of the methodologies employed in spatial statistics, population genetics and climate modeling during scans for signatures of natural selection from genomic data.
Exploring the population genetic consequences of the colonization process with spatio‐temporally explicit models: insights from coupled ecological, demographic and genetic models in montane grasshoppers
Authors: LACEY KNOWLES L. , ALVARADO‐SERRANO DIEGO F.
Published: August 2010

Understanding the genetic consequences of shifting species distributions is critical for evaluating the impact of climate‐induced distributional changes. However, the demographic expansion associated with the colonization process typically takes place across a heterogeneous environment, with population sizes and migration rates varying across the landscape. Here we describe an approach for coupling ecological‐niche models (ENMs) with demographic and genetic models to explore the genetic consequences of distributional shifts across a heterogeneous landscape. Analyses of a flightless grasshopper from the sky islands of the Rocky Mountains of North America are used to show how biologically informed predictions can be generated about the genetic consequences of a colonization process across a spatially and temporally heterogeneous landscape (i.e. the suitability of habitats for the montane species differs across the landscape and is itself not static, with the displacement of contemporary populations into glacial refugia). By using (i) ENMs for current climatic conditions and the last glacial maximum to (ii) parameterize a demographic model of the colonization process, which then (iii) informs coalescent simulations, a set of models can be generated that capture different processes associated with distributional shifts. We discuss how the proposed approach for model generation can be integrated into a statistical framework for estimating key demographic parameters and testing hypotheses about the conditions for which distributional shifts may (or may not) enhance species divergence, including the importance of habitat stability, past gene‐flow among currently isolated populations, and maintenance of refugial populations in multiple geographic regions.
Common factors drive adaptive genetic variation at different spatial scales in Arabis alpina
Authors: MANEL S. , PONCET B. N. , LEGENDRE P. , GUGERLI F. , HOLDEREGGER R.
Published: August 2010

A major challenges facing landscape geneticists studying adaptive variation is to include all the environmental variables that might be correlated with allele frequencies across the genome. One way of identifying loci that are possibly under selection is to see which ones are associated with environmental gradient or heterogeneity. Since it is difficult to measure all environmental variables, one may take advantage of the spatial nature of environmental filters to incorporate the effect of unaccounted environmental variables in the analysis. Assuming that the spatial signature of these variables is broad‐scaled, broad‐scale Moran’s eigenvector maps (MEM) can be included as explanatory variables in the analysis as proxies for unmeasured environmental variables. We applied this approach to two data sets of the alpine plant Arabis alpina. The first consisted of 140 AFLP loci sampled at 130 sites across the European Alps (large scale). The second one consisted of 712 AFLP loci sampled at 93 sites (regional scale) in three mountain massifs (local scale) of the French Alps. For each scale, we regressed the frequencies of each AFLP allele on a set of eco‐climatic and MEM variables as predictors. Twelve (large scale) and 11% (regional scale) of all loci were detected as significantly correlated to at least one of the predictors ( > 0.5), and, except for one massif, 17% at the local scale. After accounting for spatial effects, temperature and precipitation were the two major determinants of allele distributions. Our study shows how MEM models can account for unmeasured environmental variation in landscape genetics models.
Inferring landscape effects on gene flow: a new model selection framework
Authors: SHIRK A. J. , WALLIN D. O. , CUSHMAN S. A. , RICE C. G. , WARHEIT K. I.
Published: August 2010

Populations in fragmented landscapes experience reduced gene flow, lose genetic diversity over time and ultimately face greater extinction risk. Improving connectivity in fragmented landscapes is now a major focus of conservation biology. Designing effective wildlife corridors for this purpose, however, requires an accurate understanding of how landscapes shape gene flow. The preponderance of landscape resistance models generated to date, however, is subjectively parameterized based on expert opinion or proxy measures of gene flow. While the relatively few studies that use genetic data are more rigorous, frameworks they employ frequently yield models only weakly related to the observed patterns of genetic isolation. Here, we describe a new framework that uses expert opinion as a starting point. By systematically varying each model parameter, we sought to either validate the assumptions of expert opinion, or identify a peak of support for a new model more highly related to genetic isolation. This approach also accounts for interactions between variables, allows for nonlinear responses and excludes variables that reduce model performance. We demonstrate its utility on a population of mountain goats inhabiting a fragmented landscape in the Cascade Range, Washington.
Landscape modelling of gene flow: improved power using conditional genetic distance derived from the topology of population networks
Authors: DYER RODNEY J. , NASON JOHN D. , GARRICK RYAN C.
Published: August 2010

Landscape genetics is a burgeoning field of interest that focuses on how site‐specific factors influence the distribution of genetic variation and the genetic connectivity of individuals and populations. In this manuscript, we focus on two methodological extensions for landscape genetic analyses: the use of conditional genetic distance (cGD) derived from population networks and the utility of extracting potentially confounding effects caused by correlations between phylogeographic history and contemporary ecological factors. Individual‐based simulations show that when describing the spatial distribution of genetic variation, cGD consistently outperforms the traditional genetic distance measure of linearized FST under both 1‐ and 2‐dimensional stepping stone models and Cavalli‐Sforza and Edward’s chord distance Dc in 1‐dimensional landscapes. To show how to identify and extract the effects of phylogeographic history prior to embarking on landscape genetic analyses, we use nuclear genotypic data from the Sonoran desert succulent Euphorbia lomelii (Euphrobiaceae), for which a detailed phylogeographic history has previously been determined. For E. lomelii, removing the effect of phylogeographic history significantly influences our ability to infer both the identity and the relative importance of spatial and bio‐climatic variables in subsequent landscape genetic analyses. We close by discussing the utility of cGD in landscape genetic analyses.
Was it an explosion? Using population genetics to explore the dynamics of a recent radiation withinProtea(Proteaceae L.)
Authors: PRUNIER RACHEL , HOLSINGER KENT E.
Published: August 2010

Adaptive radiations likely underlie much of the world’s diversity, especially that of hyper‐diverse regions. They are usually characterized by a burst of speciation early in their evolutionary history, a pattern which can be detected using population genetic tools. The Cape Floristic Region (CFR) of southwestern South Africa is home to many spectacular plant radiations. Here, we investigate the white proteas (ProteasectionExsertae), a typical CFR radiation, to determine if it demonstrates the burst of speciation associated with adaptive radiations in recent models. Inferences from individual assignment, tree‐based population relationships, and pairwiseF‐statistics based on 10 microsatellite loci reveal that while the white proteas radiated recently they did not radiate explosively. In addition, we found evidence that there is little gene flow between sampled populations of most species. Taken together, these results demonstrate that within a small clade, the processes underlying the radiation are different from those envisioned by current models of adaptive radiation and suggest that geographical isolation could have played a role in the diversification of the group. Our study implicates both adaptive and non‐adaptive processes in the evolution of botanical diversity of the CFR.
Adaptive responses to purine starvation in Leishmania donovani
Authors: Carter Nicola S. , Yates Phillip A. , Gessford Sarah K. , Galagan Sean R. , Landfear Scott M. , Ullman Buddy
Published: August 2010

Starvation of Leishmania donovani parasites for purines leads to a rapid amplification in purine nucleobase and nucleoside transport. Studies with nucleoside transport‐deficient L. donovani indicate that this phenomenon is mediated by the nucleoside transporters LdNT1 and LdNT2, as well as by the purine nucleobase transporter LdNT3. The escalation in nucleoside transport cannot be ascribed to an increase in either LdNT1 or LdNT2 mRNA. However, Western analyses on parasites expressing epitope‐tagged LdNT2 revealed a marked upregulation in transporter protein at the cell surface. Kinetic investigations of LdNT1 and LdNT2 activities from purine‐replete and purine‐starved cells indicated that both transporters exhibited significant increases in Vmax for their ligands under conditions of purine‐depletion, although neither transporter displayed an altered affinity for its respective ligands. Concomitant with the increase in purine nucleoside and nucleobase transport, the purine salvage enzymes HGPRT, XPRT and APRT were also upregulated, suggesting that under conditions where purines are limiting, Leishmania parasites remodel their purine metabolic pathway to maximize salvage. Moreover, qRT‐PCR analyses coupled with cycloheximide inhibition studies suggest that the underlying molecular mechanism for this augmentation in purine salvage occurs post‐transcriptionally and is reliant on de novo protein synthesis.
Seasonal pattern of abundance of honeyeaters and their resources in heathland areas near Sydney
Authors: PYKE GRAHAM H.
Published: August 2010

Abundances of honeyeaters, flowers and flying insects, the daily nectar‐energy production per flower and the average size of flying insects were estimated every three weeks for circles of radius 20 m located in three heathland areas near Sydney. Seasonal fluctuations in honeyeater density showed no apparent relationship with seasonal fluctuations in nectar‐energy productivity or in biomass of flying insects. Variation between circles in honeyeater density was also unrelated to spatial variation in energy productivity and insect biomass. The relatively low incidence of nectar‐feeding and high incidence of flying exhibited by birds observed during troughs in nectar‐energy production suggest that many of these birds are transient and that their density may consequently be unrelated to local conditions.
Decomposition of litter in sub‐alpine forests of Eucalyptus delegatensis, E. pauciflora and E. dives
Authors: WOODS P. V. , RAISON R. J.
Published: August 2010

The rate of decomposition of summer leaf‐fall (abscised leaves), winter leaf‐fall (containing some green leaves) and mature green (picked) leaves was assessed in sub‐alpine forests of E. delegatensis (R. T. Baker), E. pauciflora (Sieb. ex Spreng) and E. dives (Schau.) in the Brindabella Range, Australian Capital Territory, using litter bag and tethered leaf techniques. The relative contribution of leaching, microbial respiration and grazing by invertebrate macrofauna to loss of leaf weight was determined. The effect of leaching and microbial respiration was assessed in terms of weight loss per unit area of leaf (specific leaf weight), while losses due to macro‐faunal grazing were assessed by measuring reductions in leaf area. Litter decomposition constants for litter components (leaf, bark, wood) and total litter were determined from long‐term records of litterfall and accumulated litter.

Weight losses of abscised leaves during the initial 12 months ranged from 25% for E. pauciflora to 39% for E. delegatensis and were almost entirely due to reduction in specific leaf weight. Losses in the weight of leaves falling in winter ranged from 38 to 49%, while green leaves lost 45 ‐ 59%. Approximately 50% of the total weight loss of green leaves was due to a loss in leaf area caused by skeletonization by litter macrofauna. Thus abscised leaves rather than green leaves must be used for measuring litter decomposition rates since abscised leaves constitute most of the litterfall in eucalypt forests.

Leaves placed in the field in autumn decomposed slowly during the first summer, while the rate increased during the second winter and summer. Low litter moisture content appears to limit decomposition in the initial summer period in all communities, after which litterfall provides a mulch which reduces the rate of desiccation of lower litter layers. A simple linear regression model relating decomposition rate to the number of days (D) when litter moisture content exceeded 60% ODW accounted for 63‐83% of the variation in decomposition of leaves in the field. Inclusion of mean monthly air temperature (T) and the product of D and T (day degrees when litter was wet) in a multiple linear regression increased the variation in decomposition accounted for to 80 – 90%.

The rate of weight loss showed a positive linear relationship with the initial concentration of nitrogen (N) or phosphorus (P) in the leaf. These concentrations are an index of the decomposability of leaf substrates (e.g. degree of sclerophylly or lignification).

The rate of loss of specific weight was similar for tethered leaves and for leaves enclosed in mesh bags. Measured loss in specific leaf weight after 70 – 90 weeks was less than that predicted using decomposition constants (k).
Suburban development and resultant changes in the vegetation of the bushland of the northern Sydney region
Authors: CLEMENTS ANNEMARIE
Published: August 2010

Bushland sites in the northern suburbs of Sydney were compared to sites in Brisbane Waters National Park, Ku‐ring‐gai Chase National Park and Royal National Park which are relatively unaffected by suburban development. Both shale‐derived and sandstone‐derived soil in four physiographical locations were examined, with three replicates of each of the 16 combinations.

Phosphorus levels are higher in the soils of suburban sites compared to soils derived from similar rock bases in non‐suburban sites. Phosphorus levels are also higher on shale‐derived than on sandstone‐derived soils, and lower on hilltops than in other physiographic positions. Suburban sandstone sites have soil phosphorus levels similar to those of non‐suburban shale sites.

Three major and three minor clusters of species were distinguished using a hierarchical agglomerative clustering. The major clusters consisted of (1) species commonly associated with wet sclerophyll forests and rainforest margins, (2) species directly or indirectly related to the presence of man, and (3) species associated with dry sclerophyll forests and heaths.

Using analyses of variance and covariance, and logit models, the abundance of the first main cluster was related to nutrient‐rich soils and the abundance of the third main cluster to low nutrient soils whereas the presence of the second main cluster was almost entirely restricted to sites surrounded by suburbs.

The development of suburbs around vegetation patches has led to an increase in the abundance of native and exotic mesomorphic species and the addition of phosphorus to the soils. The data presented in this paper indicates that high phosphorus levels and presence of mesomorphic species are related.
Short note Successive approximation in pattern analysis
Authors: BUCKLEY R. C.
Published: August 2010

The analysis of vegetation pattern in semi‐arid eucalypt woodland by Harrington et al, (1981), and its recent critique by Dale (1982), place insufficient emphasis on the important role of successive approximation in pattern analysis. A single stage analysis can reveal first order patterns effectively, but is generally ineffective and inefficient in revealing vegetation patterns of higher order, no matter how sophisticated the numerical techniques employed. For a given total analytical effort, a more effective and efficient strategy to reveal such higher order patterns will generally be to partition the overall analytical effort into successive stages of sampling and interpretation, one stage for each order of pattern, with the sampling strategy at each stage based on the patterns determined during previous stages.
Decomposition of litter from common woody species of kauri (Agathis australisSalisb.) forest in northern New Zealand
Authors: ENRIGHT N. J. , OGDEN J.
Published: August 2010

Rates of weight loss and release of Na, K, Ca, Mg and P were investigated for common components of kauri forest litterfall in experiments using mesh bags. Weight loss over both 3 and 12 months was maximal for broadleaf mesophyllous species such asMelicytus ramiflorusand minimal for gymnosperms (e.g.Phyllocladus trichomanoides)and sclerophyllous broadleaf species (e.g.Knightia excelsa).Tree fern and palm frond material, common in these forests, was also slow to decompose, being grouped with the gymnosperm and sclerophyllous species.

The order of release of nutrients from decomposing litter was P < Mg ∼ Ca < Na ∼ K. This order varied somewhat with species and litter type. Sodium and K are lost rapidly regardless of the rate of weight loss while Mg and Ca tend to follow the weight loss trend more closely. Loss of weight and nutrients was faster for freshly picked green leaves than for senesced leaves.

Agathis australislitter, which may represent up to 50% of total litterfall, loses both weight and nutrients more slowly than broadleaf mesophyll species.
Population dynamics of the shrub Acacia suaveolens (Sm.) Willd.: Survivorship throughout the life cycle, a synthesis
Authors: AULD TONY D.
Published: August 2010

Survivorship in Acacia suaveolens was assessed through seedling and adult stages. Moisture stress was found to be the critical factor limiting early seedling survival. Both seedling and adult populations were characterized by periods of low mortality interspersed with pulses of high mortality. A composite survivorship curve for A. suaveolens based on nine sites predicts that some 20–25 years after afire, established plants should disappear from the above‐ground flora if another fire does not occur.

Fecundity and survivorship data were used to estimate the flux of seed in the soil over time in a hypothetical A. suaveolens population. From this it was predicted that, following establishment of plants after a fire, the seed‐bank would rapidly reach a maximum after 6 years and thereafter slowly decline, until after 60 years there would be only as many seeds as there were original parental plants. The situation would vary with predispersal seed predation, seed predation on the soil surface, seed dispersal by ants to ‘unsafe sites’ and the size of the initial seed‐bank prior to establishment. Only after a very long inter‐fire period would A. suaveolens be eliminated from a site. Elimination of the species is also possible under very frequent fires. A 2–5 year fire‐free period is needed for plants to reach maturity and another 6 years are needed to maximize seed input into the soil seed‐bank. In addition, seedling recruitment following cool burns is low to non‐existent as dormancy is not broken for most seeds in the soil during such burns.
Nectar dispersion patterns in three Australian plant species
Authors: ZIMMERMAN MICHAEL , NAGY ERIC S. , GALLOWAY LAURA
Published: August 2010

Standing crops of floral nectar were measured from three species of plants: Dampiera stricta, Goodenia bellidifolia and Aotus ericoides. The amount of nectar in nearest neighbour blossoms in nine of the 10 samples were significantly correlated with one another suggesting that patches of high and low reward quality exist in these species. The patterns further suggest that the pollinators of these species employ arearestricted searching behaviour. The range of variability in standing crops for all three species was quite high. The nature of that variability suggests that A. ericoides is less variable in its rate of nectar production than are the other two species and, therefore, that it has the potential to be more tightly co‐evolved with its pollinators.
Pollen movement to flowering canopies of pistillate individuals of three rain forest tree species in tropical Australia
Authors: HOUSE SUSAN M.
Published: August 2010

This study measured the quantities of effective pollen vectors and their pollen loads arriving at the canopies of dioecious tropical rain forest trees in north‐east Queensland. Population flowering synchrony, effective pollinator populations and pollen loads transferred between staminate and pistillate trees were compared among three insect‐pollinated tree species. All three were visited by a wide range of insects, 75% of which (mostly 3–6 mm long) carried conspecific pollen. Fewer than 8% of individual insects were found to be carrying single‐species pollen exclusively and none could be described as specialist pollen foragers. The introduced honeybee carried greater quantities of pollen than any native species but was not necessarily a reliable pollinator.

The brief flowering periods in Neolitsea dealbata (3–4 weeks) and Litsea leefeana (4–5 weeks) populations were synchronized among individuals. Flowering in the Diospyros pentamera population extended over 15 weeks and most individuals were in flower for most of this period. Staminate trees began flowering earlier, produced more flowers and attracted relatively more insects than did pistillate trees, suggesting a density‐dependent response of pollinators to flowering performance. Pollen was trapped in greater quantities on insects at staminate trees than at pistillate trees.

Insect numbers increased at peak flowering periods and Diptera were the most abundant flower visitors. Anthophilous Coleoptera were more numerous at staminate than at pistillate trees in all three tree species populations. Larger quantities of pollen were mobilized during peak flowering times although the greatest quantities were transferred to pistillate canopies towards the end of the population flowering periods. Diptera carried pollen more often to pistillate N. dealbata and L. leefeana trees than did other groups whereas Coleoptera carried pollen more often to pistillate D. pentamera trees. The two contrasting flowering performances in the three tree species are discussed with reference to mechanisms that facilitate pollen transfer between staminate and pistillate trees.
Fire temperatures and follicle‐opening requirements in 10 Banksia species
Authors: ENRIGHT NEAL J. , LAMONT BYRON B.
Published: August 2010

Temperature requirements for follicle rupture were assessed in 10 Banksia species from south‐western Australia. Species examined varied in degree of serotiny, persistence of dead florets, height, follicle size and number, and dependence on seed for regeneration.

When treated for 2 min at temperatures over the range 100–500°C, follicles of some species ruptured at quite low temperatures (e.g. Banksia tricuspis with 50% opening at 145°C). Others required substantially higher temperatures (e.g. Banksia hookeriana with 50% opening at 390°C). There was a significant correlation between temperature requirements for follicle rupture and persistence of the highly combustible florets. However, there was no overall correlation between degree of serotiny and temperature requirements, nor with the other biological attributes assessed.

Cone temperatures and follicle rupture in five co‐occurring Banksia species were monitored for an experimental spring burn in Banksia‐ dominated shrubland. Temperatures recorded at follicle surfaces were higher than those needed for follicle rupture in the four species with persistent florets. Critical temperatures were rarely reached for the weakly serotinous Banksia menziesii which possesses bare cones and an open canopy.
Reproduction and perennation of Chondrilla juncea L. (skeleton weed) in the Western Australian wheatbelt
Authors: PANETTA F. D.
Published: August 2010

Survivorship of first‐year plants of Chondrilla juncea was considerably higher on a deep yellow sand than on a yellow duplex soil. Mortality on the latter soil was associated with drying of the Al horizon during early summer. No plants produced seeds in their first year of growth on the duplex soil. However, during both years of the study, first‐year individuals of both forms of C. juncea produced viable seeds when growing on the deep sand. Higher population growth rates could be expected on deep sands, owing to a combination of earlier reproduction and greater survivorship through the first summer. It is suggested that whilst the entire wheatbelt might be climatically suitable for C. juncea, the invasive potential of this weed might be restricted by edaphic characteristics over large areas.
An example of Holocene vegetation stability from Camerons Lagoon, a near treeline site on the Central Plateau, Tasmania
Authors: THOMAS IAN , HOPE GEOFFREY
Published: August 2010

Abstract
A discontinuous record of vegetation over the past 7500 years was obtained through pollen analysis of pond sediments from an extensive treeless plain on the relatively dry Central Plateau of Tasmania. The results demonstrate continuity of treeless conditions, which probably persisted from the Pleistocene throughout the Holocene, up to the present day. Some changes to the structure of the grassland were observed, especially over the past 200 years. Analysis of carbonized particles showed that fires had been infrequent over the period examined. It seems that this area, close to the altitudinal tree limit, has remained a natural grassland, and the hypothesis of Jackson (1973), that unreliable summer conditions may be a major factor in maintaining open conditions, is supported. Parts of the Central Plateau may thus preserve plant communities with some of the floristic elements and structure of widespread Bassian grasslands of the Late Pleistocene.
Phytophagous insect‐woody sprout interactions in tropical eucalypt forest. II. Insect community structure
Authors: FENSHAM R. J.
Published: August 2010

Abstract
Sucking insects constituted 79% of all phytophagous insects collected from woody sprouts in the ground layer of a tropical eucalypt forest. Mobile insect groups such as non‐psyllid Hemiptera and Orthoptera were relatively frequent in this environment compared to temperate, Eucalyptus‐dominated vegetation. The high fire frequency of the tropical eucalypt forest may favour mobile insect groups. The capture of sucking insects and caterpillars peaked in dry season samples. Other patterns of abundance of phytophagous insect groups showed little consistency in their seasonal trends between host species or between vegetation types within host species. Disparities between chewing insect abundance in daytime samples and the damage chewing insects cause, may result from disproportionate consumption by large, mainly nocturnal insects, such as members of the Orthoptera. In this study, 21% of insect species were specialists on single plant species. This study suggested that insect abundance reflected the growth patterns of woody sprouts after regular burning, rather than that plant growth and development were tuned to the pressures of insect herbivory.
Contribution of oribatid and mesostigmatid soil mites in ecologically based estimates of global species richness
Authors: Osler Graham H. R. , Beattie Andrew J.
Published: August 2010

Erwin’s method for estimating total global species richness assumes some host‐specificity among the canopy arthropods. This study examined possible host habitat specialization in two major groups of soil arthropods, the oribatid and mesostigmatid mites, by sampling beneath three tree species:Eucalyptus pilularisSmith,Eucalyptus propinquaDeane and Maiden andAllocasuarina torulosa(Aiton) L. Johnson. The sample sites were in the Lansdowne State Forest, New South Wales, Australia and the three tree species were selected on the basis of their known differential effects on soil. Sampling was conducted over three seasons, and 79 oribatid and 34 mesostigmatid species were identified from 25 196 and 3634 individuals, respectively. Tree species had little effect on mite species composition with only three oribatid species and no mesostigmatid species identified as host‐habitat specialists using a niche breadth measure. Of mite species found underE. pilularis,E. propinquaandA. torulosatrees, 2%, 1% and 0% were defined as host‐habitat specialists, respectively. In contrast, tree species had significant and consistent effects on mite community structure, which differed in relative abundance of the oribatid species, their size class distributions and species rankings. In the mesostigmatid communities, there was a difference in the ranking of the mite species among tree species. Although it was demonstrated that tree species have an impact on the soil environment, the differences between tree species were insufficient to change species composition. The low degree of host‐habitat specialization suggested that other factors were more important for determining mite species composition at a site, and soil mite host‐habitat specialization may not make a large contribution to estimates of total global species richness using methods such as those proposed byErwin (1982).