bluuebunny/crossref_metadata_2025 huggingface dataset:
Traversing the mountaintop: world fossil fuel production to 2050
Authors: Nehring Richard
Published: September 2009

During the past century, fossil fuels—petroleum liquids, natural gas and coal—were the dominant source of world energy production. From 1950 to 2005, fossil fuels provided 85–93% of all energy production. All fossil fuels grew substantially during this period, their combined growth exceeding the increase in world population. This growth, however, was irregular, providing for rapidly growing
per capita
production from 1950 to 1980, stable
per capita
production from 1980 to 2000 and rising
per capita
production again after 2000. During the past half century, growth in fossil fuel production was essentially limited by energy demand. During the next half century, fossil fuel production will be limited primarily by the amount and characteristics of remaining fossil fuel resources. Three possible scenarios—low, medium and high—are developed for the production of each of the fossil fuels to 2050. These scenarios differ primarily by the amount of ultimate resources estimated for each fossil fuel. Total fossil fuel production will continue to grow, but only slowly for the next 15–30 years. The subsequent peak plateau will last for 10–15 years. These production peaks are robust; none of the fossil fuels, even with highly optimistic resource estimates, is projected to keep growing beyond 2050. World fossil fuel production
per capita
will thus begin an irreversible decline between 2020 and 2030.
Making family planning accessible in resource-poor settings
Authors: Prata Ndola
Published: September 2009

It is imperative to make family planning more accessible in low resource settings. The poorest couples have the highest fertility, the lowest contraceptive use and the highest unmet need for contraception. It is also in the low resource settings where maternal and child mortality is the highest. Family planning can contribute to improvements in maternal and child health, especially in low resource settings where overall access to health services is limited. Four critical steps should be taken to increase access to family planning in resource-poor settings: (i) increase knowledge about the safety of family planning methods; (ii) ensure contraception is genuinely affordable to the poorest families; (iii) ensure supply of contraceptives by making family planning a permanent line item in healthcare system's budgets and (iv) take immediate action to remove barriers hindering access to family planning methods. In Africa, there are more women with an unmet need for family planning than women currently using modern methods. Making family planning accessible in low resource settings will help decrease the existing inequities in achieving desired fertility at individual and country level. In addition, it could help slow population growth within a human rights framework. The United Nations Population Division projections for the year 2050 vary between a high of 10.6 and a low of 7.4 billion. Given that most of the growth is expected to come from today's resource-poor settings, easy access to family planning could make a difference of billions in the world in 2050.
The theoretical and political framing of the population factor in development
Authors: Campbell Martha , Bedford Kathleen
Published: September 2009

The silence about population growth in recent decades has hindered the ability of those concerned with ecological change, resource scarcity, health and educational systems, national security, and other global challenges to look with maximum objectivity at the problems they confront. Two central questions about population—(i) is population growth a problem? and (2) what causes fertility decline?—are often intertwined; if people think the second question implies possible coercion, or fear of upsetting cultures, they can be reluctant to talk about the first. The classic and economic theories explaining the demographic transition assume that couples want many children and they make decisions to have a smaller family when some socio-economic change occurs. However, there are numerous anomalies to this explanation. This paper suggests that the societal changes are neither necessary nor sufficient for family size to fall. Many barriers of non-evidence-based restrictive medical rules, cost, misinformation and social traditions exist between women and the fertility regulation methods and correct information they need to manage their family size. When these barriers are reduced, birth rates tend to decline. Many of the barriers reflect a patriarchal desire to control women, which can be largely explained by evolutionary biology. The theoretical explanations of fertility should (i) attach more weight to the many barriers to voluntary fertility regulation, (ii) recognize that a latent desire to control fertility may be far more prevalent among women than previously understood, and (iii) appreciate that women implicitly and rationally make benefit–cost analyses based on the information they have, wanting modern family planning only after they understand it is a safe option. Once it is understood that fertility can be lowered by purely voluntary means, comfort with talking about the population factor in development will rise.
Where next?
Authors: Potts Malcolm
Published: September 2009

This paper provides a personal perspective on the rich discussions at theBixby Forum. The size, rate of growth and age structure of the human population interact with many other key factors, from environmental change to governance. While the details of future interactions are sometimes difficult to predict, taken together they pose sombre threats to a socially and economically sustainable future for the rich and to any realistic possibility of lifting the world's bottom two billion people out of poverty. Adaptive changes will be needed to cope with an ageing population in countries with low fertility or below, but these are achievable. More worrying, continued rapid population growth in many of the least developed countries could lead to hunger, a failure of education to keep pace with growing numbers, and conflict. The assumption that the demographic transition from high to low birth rates occurs as a result of exogenous social and economic forces is being replaced by a clearer understanding of the many barriers that separate women from the knowledge and technologies they need to manage their childbearing within a human rights framework. The forum ended with a clear consensus that much more emphasis needs to be given to meeting the need for family planning and to investing in education.
Population priorities: the challenge of continued rapid population growth
Authors: Turner Adair
Published: September 2009

Rapid population growth continues in the least developed countries. The revisionist case that rapid population could be overcome by technology, that population density was advantageous, that capital shallowing is not a vital concern and that empirical investigations had not proved a correlation between high population growth and low
per capita
income was both empirically and theoretically flawed. In the modern world, population density does not play the role it did in nineteenth-century Europe and rates of growth in some of today's least developed nations are four times than those in nineteenth-century Europe, and without major accumulation of capital
per capita
, no major economy has or is likely to make the low- to middle-income transition. Though not sufficient, capital accumulation for growth is absolutely essential to economic growth. While there are good reasons for objecting to the enforced nature of the Chinese one-child policy, we should not underestimate the positive impact which that policy has almost certainly had and will have over the next several decades on Chinese economic performance. And a valid reticence about telling developing countries that they must contain fertility should not lead us to underestimate the severely adverse impact of high fertility rates on the economic performance and prospects of many countries in Africa and the Middle East.
Invertebrate prey and predatory behaviour of the omnivorous African tortoiseKinixys spekii
Authors: Hailey Adrian , Coulson Ian M. , Mwabvu Tarombera
Published: September 2009

Invertebrates form an important part of the diet in the omnivorous African tortoises of the genusKinixys. Millipede prey ofKinixys spekiiin Zimbabwe had a mean volume of 0.9 ml, and made up 64.7% of invertebrate food by volume; beetles made up most of the remainder and had a mean volume of 1.4 ml. The mean mass of invertebrate prey was 0.19% of tortoise mass, a similar value of relative prey mass to many insectivorous lizards. Tortoises preferentially attacked moving millipedes at or just behind the head, but predatory behaviour was otherwise unspecialized, with tortoises killing millipedes by ingesting them in pieces. Handling times of millipede prey varied significantly with relative prey mass, defensive behaviour, and direction of ingestion. The profitability (mass intake/handling time) of millipedes was maximal at a relative prey mass of 0.2%; the basis on which prey are selected is discussed.
Common use of sleeping sites by two primate species in Tana River, Kenya
Authors: Wahungu Geoffrey M.
Published: September 2009

Choice of sleeping sites by two species of primates sharing two adjacent patches of gallery forest in Tana River, Kenya, was studied between August 1992 and February 1993. One group each of the Tana crested mangabey, Cercocebus galeritus galeritus Peters, and yellow baboon, Papio cynocephalus cynocephalus L., interchangeably shared nine sleeping sites distributed among four tree species, Acacia robusta Burch., Ficus sycomorus L., Abizzia gummifera (J. F. Gmel.) E. A. Sm. and Pachystela msolo (Engl.) Engl. The trees used by both species as sleeping sites were mainly tall trees with canopy level or emergent crowns. The trees had relatively larger crowns and lower percentage canopy cover compared to other trees at the site and were characterized by poor to moderate accessibility. Overlap in use of sleeping sites was never simultaneous and baboons occasionally supplanted mangabeys. Site choice by these two primates appeared to be influenced by predation risk, the feeding area used in the late afternoon, daily range and the availability of trees with the preferred structural characteristics. Sleeping sites appeared to be limited during and immediately after the wet season, when the frequency of supplantings increased. This observation is attributed to an increase in percentage canopy cover.
Seasonality in elephant dung decay and implications for censusing and population monitoring in south‐western Cameroon
Authors: Nchanji Anthony Chifu , Plumptre Andrew J.
Published: September 2009

Dung decay rates have been used in the past to correct elephant dung counts to estimates of population numbers. These assume that the dung is in a ‘steady state’ where production rates are equal to disappearance rates. The inter‐seasonal variation in decay rates, however, has never been fully investigated for elephant dung. This study, in the Banyang‐Mbo Wildlife Sanctuary in SW Cameroon, investigated whether a single dung decay rate is really appropriate when converting dung counts to population density estimates. A total of 870 fresh elephant dung‐piles were monitored until they had completely decayed, with at least 60 fresh dung piles located each month of the year between July 1994 to June 1995. The elephant dung decay rate obtained was 55.6% to 66.7% lower than those obtained for the rainforests of Gabon. This has implications for using decay rates obtained elsewhere to compute elephant densities from dung counts. Statistically significant differences were found in the mean duration of dung‐piles between different months and different seasons. Environmental variables, with the exception of rainfall, did not aid in predicting the duration of elephant dung‐piles. The model of Plumptre & Harris was used to estimate the standing crop of dung at any particular time of the year. The results show that, if there was no emigration of elephants from the population, then there was only a three‐month period when the dung was in a ‘steady state’. If emigration occurred during the wet season as is thought to occur then there was no period of ‘steady state’.
How reliable are dung counts for estimating elephant numbers?
Authors: Barnes R. F. W.
Published: September 2009

Dung counts are the most commonly used techniques for estimating elephant numbers in forests, yet there is considerable scepticism concerning their accuracy. Published accounts of dung counts show that they give estimates similar to those from other methods for vertebrates ranging in size from lizards to elephants. For ungulates, macropods and elephants there are strong correlations between estimates from dung counts and other methods. Thus, dung counts are as accurate or inaccurate as other methods for estimating vertebrate numbers, including elephants. Dung counts for elephants give estimates that are as precise as, and sometimes more precise than, those from aerial surveys of elephants. This is because the variance in dung density is usually low and results in a lower than expected variance for the final elephant estimate when combined with the variances of defecation and decay rates. Dung counts may be more appropriate than aerial surveys for monitoring small or declining elephant populations.
Validation of observer and aircraft calibration for aerial surveys of animals
Authors: Ottichilo Wilber K. , Khaemba Wilson M.
Published: September 2009

Calibration procedures to determine strip widths for use by the Department of Resource Surveys and Remote Sensing (DRSRS) in its aerial surveys are validated by statistical analysis. Tests were made for differences in observer, aircraft and between using photography (camera) and direct observation (naked eye) in the determination of strip widths on the ground. The relationship between strip widths measured on the ground and in the air was determined using regression analysis. Tests were also made for differences between population estimates reported by DRSRS and those recalculated using reported strip widths for elephant, kongoni, wildebeest and cattle. There appears to be no significant differences between observer performance and between reported and recalculated population estimates for all species except cattle. A significant difference was found between strip widths obtained by photography and those through direct observation, with photography values being 14% higher at ground level. Strip widths measured while the aircraft was in the air were highly correlated to those measured while on the ground (r = 0.97). Overall, it can be concluded that the DRSRS standardization of observers, calibration of the aircraft and calculation of population estimates were carried out correctly. Finally, it is recommended that the difference in strip widths determined from photography and through direct observation needs to be considered in the final calculation of population estimates.
Regeneration of indigenous trees in Mgahinga Gorilla National Park, Uganda
Authors: Lejju Julius B. , Oryem‐Origa Hannington , Kasenene John M.
Published: September 2009

This study examines the regeneration of indigenous tree species in the formerly encroached area in Mgahinga Gorilla National Park (MGNP), south‐western Uganda. Before gazetting in 1992, MGNP had basically been agricultural land for well over 50 years. The distribution of exotic vegetation was established using a Geographical Positioning System receiver and indigenous vegetation was sampled by establishment of quadrats along transect lines.

Observations indicated that approximately 2% of the old cropland was covered by exotic woodlots. Black wattle (Acacia mearnsii) and Eucalyptus trees were found to be the most widely distributed and Pinus patula the least distributed species in the park. Species numbers of indigenous trees (n = 26) were high in the old cropland, compared with twelve species observed in exotic woodlots. The natural forest supported the highest (75%) stem density and the lowest (4%) stem density was recorded in exotic woodlots. Seedling class (< 2 cm, d.b.h.) accounted for the majority of juveniles, with the lowest stem density (1350 seedlings ha−1) recorded in exotic woodlots compared with 6609 seedlings ha−1 in the old cropland and 24,625 seedlings ha−1 in the natural forest. The levels of tree diversity and stocking characteristics recorded under the exotic species suggest that a low diverse community of native species may exploit this environment.
Breeding birds in the tropical rain forests of Kibale National Park, Uganda
Authors: Dranzoa Christine
Published: September 2009

A combination of trapping and foot surveys was used to assess the breeding status of birds in unlogged and logged sites in the tropical rain forest of Kibale National Park, Uganda. Breeding of forest edge and gap species was greatly enhanced by logging, whereas crevice and hole nesting specialist breeders were adversely affected. Egg‐laying periods corresponded to higher rainfall regimes at the nearby field station. The relevance of these findings to bird conservation is discussed.
An ecological basis for large group size in Colobus angolensis in the Nyungwe Forest, Rwanda
Authors: Fimbel Cheryl , Vedder Amy , Dierenfeld Ellen , Mulindahabi Felix
Published: September 2009

Angolan black‐and‐white colobus monkeys (Colobus angolensis, Sclater 1980) in the Nyungwe Forest Reserve, Rwanda, are anomalous compared with conspecifics and congeners elsewhere, because they form exceptionally large groups, in excess of 300 individuals, and because of their unusually high consumption of mature leaves (∼40% of annual diet). Site factors at the Nyungwe Forest in southern Rwanda are believed to contribute to the unusual socio‐ecology of the C. angolensis residing there. Foremost, the forest provides an abundance of mature leaves that are higher in nutritional quality (protein : fibre) compared with mature leaves analysed at other African sites. The combination of a cool high elevation locale, and a relatively open canopy, may contribute to the production of high quality mature leaves at ground level and in the canopy at the Nyungwe Forest. We believe that the almost unrestricted availability of acceptable foods for Nyungwe's folivorous colobines minimizes the potential for exploitation competition for food, and is a key factor in allowing them to form exceptionally large groups.
Seasonal changes in habitat preferences of two closely related millipede species
Authors: Greyling M. D. , Van Aarde R. J. , Ferreira S. M.
Published: September 2009

The habitat preferences of two closely related millipede species,Centrobolus richardiiandC. fulgidus, were investigated on three different seral stages of a coastal dune forest successional sere north of Richards Bay, South Africa. Fixed‐width transects were used to survey millipedes in three habitats of different ages. Habitat preference occurred on both inter‐ and intra‐site levels and was influenced by season. A habitat shift was recorded forC. richardii, whileC. fulgiduswas dormant during the winter months, reflecting two different strategies used by these closely related species to meet their resource requirements. Successional changes previously reported are masked by these differential responses.
Clinical trial: the efficacy and safety of routine bowel cleansing agents for elective colonoscopy in persons with spinal cord injury – a randomized prospective single‐blind study
Authors: ANCHA H. R. , SPUNGEN A. M. , BAUMAN W. A. , ROSMAN A. S. , SHAW S. , HUNT K. K. , POST J. B. , GALEA M. , KORSTEN M. A.
Published: September 2009

Background  As difficulty with evacuation is a common occurrence in individuals with spinal cord injury, preparation prior to colonoscopy may be suboptimal and, perhaps, more hazardous.

Aim  To assess the safety and efficacy of bowel cleansing regimens in persons with spinal cord injury.

Methods  Randomized, prospective, single blind study comparing polyethylene glycol (PEG), oral sodium phosphosoda (OSPS) and combination of both for colonic preparation prior to colonoscopy in subjects with spinal cord injury.

Results  Thirty six subjects with eGFR ≥60 mL/min/1.73 m2 were randomized to PEG or OSPS or PEG+OSPS. Regardless of bowel preparation employed, >73% of subjects had unacceptable colonic cleansing. No subject in the OSPS preparation group demonstrated a decrease in eGFR or an increase in serum creatinine concentration from the baseline. OSPS and PEG+OSPS preparations caused a transient change in serum potassium, phosphate and calcium concentrations, but no change in electrolytes was noted in the PEG group.

Conclusions  Neither OSPS alone, PEG alone nor their combination was sufficient to prepare adequately the bowel for colonoscopy in most patients with spinal cord injury. However, administration of OSPS and/or PEG appears to be safe in the spinal cord injury population, provided adequate hydration is provided.
Systematic review: caspase‐cleaved fragments of cytokeratin 18 – the promises and challenges of a biomarker for chronic liver disease
Authors: YILMAZ Y.
Published: September 2009

Background  Biomarkers hold great promise for detecting chronic liver disease without the use of liver biopsy.

Aim  To review the usefulness of cytokeratin (CK) 18 fragments, a marker of hepatocyte apoptosis, to predict the presence of chronic liver injury.

Methods  Available literature identified from PubMed was reviewed.

Results  Levels of CK18 fragments have been shown to be elevated in hepatocellular carcinoma, viral hepatitis, alcoholic hepatitis, nonalcoholic fatty liver disease and cholestatic liver disease. In the setting of nonalcoholic fatty liver disease, CK18 fragments may distinguish nonalcoholic steatohepatitis from simple fatty liver.

Conclusions  Undoubtedly, the most promising application of CK18 fragments is currently in nonalcoholic fatty liver disease, and especially for distinguishing patients with nonalcoholic steatohepatitis vs. those with simple steatosis. Further investigations and technical improvements are required to cross the boundary from research to the clinical application of CK18 fragments as a marker of chronic liver disease.
Association between androgens, intima‐media thickness and the metabolic syndrome in obese adolescent girls
Authors: De Sousa Gideon , Brodoswki Christian , Kleber Michaela , Wunsch Rainer , Reinehr Thomas
Published: September 2009

Background  While an association between androgens and the metabolic syndrome (MS) is well established in obese women, studies concerning this relationship are scarce in obese adolescent girls. Therefore, we analysed the relationships between androgens, MS and intima‐media thickness (IMT) in this age‐group.

Methods  In 160 obese girls (aged 12–18 years, mean BMI: 32·6 ± 5·0 kg/m2), androgens [testosterone, dehydroepiandrosterone sulphate (DHEA‐S), androstenedione], SHBG and the components of MS (waist circumference, blood pressure (BP), lipids, uric acid, insulin, glucose, 2 h glucose in oral glucose tolerance test (oGTT)) were studied. Furthermore, IMT was determined in a subgroup of 71 randomly chosen girls.

Results  Testosterone correlated significantly to systolic BP (r = 0·20), diastolic BP (r = 0·24), 2 h glucose in oGTT (r = 0·30), triglycerides (r = 0·19), uric acid (r = 0·17), waist circumference (r = 0·25) and IMT (r = 0·54). These relationships (except for waist circumference and uric acid) were independent of BMI and insulin resistance index homeostasis model assessment. In contrast to testosterone, DHEA‐S, androstenedione and SHBG showed no or weaker correlations to any parameter of MS. The 48 girls with MS demonstrated significantly higher testosterone (1·8 ± 0·7 nmol/l; P = 0·025) and DHEA‐S (4·7 ± 2·3 μmol/l; P = 0·008) concentrations as compared with the 112 girls without MS (mean testosterone 1·5 ± 0·7 nmol/l, mean DHEA‐S 3·6 ± 2·3 μmol/l).

Conclusions  Testosterone was significantly related to MS and its components in obese adolescent girls independently of BMI and insulin resistance. As IMT was significantly associated with testosterone, this supports the clinical relevance of this finding.
Hypothalamic–Pituitary–Adrenal (HPA) axis functioning in relation to body fat distribution
Authors: Rutters Femke , Nieuwenhuizen Arie G. , Lemmens Sofie G. T. , Born Jurriaan M. , Westerterp‐Plantenga Margriet S.
Published: September 2009

Objective  To relate hypothalamic–pituitary–adrenal (HPA) axis functioning and HPA feedback functioning to body fat distribution in normal weight to obese subjects.

Patients  91 men and 103 women [age 18–45 years, BMI 19–35 kg/m2, waist‐to‐hip ratio (WHR) 0·6–1·1]

Measurements  Anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5‐h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test, and HPA axis functioning under a challenged condition consisting of a standardized high‐intensity test with ingestion of 4 mg dexamethasone.

Results  In men, an inverse relationship was observed between 5‐h cortisol exposure (nmol/ml) and fat mass index (FMI) (kg/m2) (r = −0·55, P < 0·001). In women, relationships were observed between 5‐h cortisol exposure (nmol/ml.min) and WHR (r = −0·49, P < 0·001), maximal workload (r = 0·32, P < 0·001) as well as oral contraceptive use (r = 0·38, P < 0·001). Similarly, in men, an inverse relationship was observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and FMI (r = −0·53, P < 0·001). In women, relationships were observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and WHR (r = −0·43, P < 0·001), maximal workload (r = 0·30, P < 0·001) as well as oral contraceptive use (r = 0·43, P < 0·001) in women. Moreover, an inverse relationship was observed between HPA axis functioning in a challenged condition expressed as percentage increase of cortisol concentrations after standardized high‐intensity test with ingestion of 4 mg dexamethasone (%) and waist circumference (r = −0·21, P < 0·10) in men and WHR (r = −0·21, P < 0·05) in women. In men, strong positive relationships were observed between FMI and waist circumference (r = 0·85, P < 0·001), as well as waist‐to‐hip ratio (r = 0·70, P < 0·001).

Conclusion  Disturbance of HPA axis functioning under basal and challenged conditions is related to visceral fat accumulation.
Association of sex hormones and C‐reactive protein levels in men
Authors: Kupelian Varant , Chiu Gretchen R. , Araujo Andre B. , Williams Rachel E. , Clark Richard V. , McKinlay John B.
Published: September 2009

Objectives  The age‐associated decline in sex hormone levels in men is paralleled by an increase in cardiovascular disease and associated risk factors including low grade chronic inflammation. The objective of this analysis was to investigate the association between sex hormone levels and C‐reactive protein (CRP) in a population‐based sample of men.

Design  Population‐based, cross‐sectional observational survey.

Participants  A multistage stratified design was used to recruit a random sample of 2301 racially and ethnically diverse men age 30–79 years. Blood samples were obtained on 1899 men. Analyses were conducted on 1559 men with complete data on CRP and sex hormone levels.

Measurements  High‐sensitivity CRP levels. The association between CRP and sex hormone levels was assessed using multiple linear regression models.

Results  An inverse association was observed, in both bivariate and multivariate analyses, between CRP and total testosterone, free testosterone and SHBG levels. These associations remained statistically significant after adjusting for age, body mass index, comorbid conditions and lifestyle factors. A positive trend between oestradiol (total and free) and CRP levels was not statistically significant.

Conclusions  A robust, inverse dose–response correlation between testosterone and SHBG levels with CRP levels provides further evidence of a potential role of androgens in inflammatory processes.
Incidence of thyrotoxicosis in childhood: a national population based study in the UK and Ireland
Authors: Williamson Scott , Greene Stephen A.
Published: September 2009

Objective  To measure the UK and Ireland incidence of childhood (<15 years) thyrotoxicosis and to describe the presenting features.

Context  Incidence data on thyrotoxicosis in childhood are not available for the UK and Ireland. Recent studies have reported an apparent increase in cases in Europe.

Design  A national prospective surveillance study for 12 months from September 2004, co‐ordinated by The British Paediatric Surveillance Unit (BPSU).

Patients and measurements  All paediatricians across the UK and Ireland were requested monthly to report new cases. Details of presenting features were then obtained by questionnaire.

Results  One hundred ten cases of acquired childhood thyrotoxicosis were identified in the UK and Ireland. The incidence of acquired thyrotoxicosis was 0·9 per 100,000 <15 years olds in the UK and Ireland, (95% CI: 0·8–1·1). Autoimmune thyrotoxicosis accounted for 96% of cases. There was an increasing incidence with age in each sex. Females have a significantly higher incidence than males in the 10‐ to 14‐year age group. A variety of presenting symptoms were reported: weight loss (64%), fatigue/tiredness (54%), change in behaviour’ (50%) and heat intolerance (47%). 4.5 % cases were asymptomatic. The commonest signs were goitre (78%) and tremor (58%). There were no cases of thyroid storm.

Conclusions  This national population survey defines the incidence of thyrotoxicosis in children in the UK and Ireland during 2004–2005, which was lower than expected in comparison with other European studies. The survey illustrates contemporary presenting characteristics of the disease.
The effects of elevated CO2 on root respiration rates of two Mojave Desert shrubs
Authors: CLARK NAOMI M. , APPLE MARTHA E. , NOWAK ROBERT S.
Published: September 2009

Although desert ecosystems are predicted to be the most responsive to elevated CO2, low nutrient availability may limit increases in productivity and cause plants in deserts to allocate more resources to root biomass or activity for increased nutrient acquisition. We measured root respiration of two Mojave Desert shrubs, Ambrosia dumosa and Larrea tridentata, grown under ambient (∼375 ppm) and elevated (∼517 ppm) CO2 concentrations at the Nevada Desert FACE Facility (NDFF) over five growing seasons. In addition, we grew L. tridentata seedlings in a greenhouse with similar CO2 treatments to determine responses of primary and lateral roots to an increase in CO2. In both field and greenhouse studies, root respiration was not significantly affected by elevated CO2. However, respiration of A. dumosa roots <1 month old was significantly greater than respiration of A. dumosa roots between 1 and 4 months old. For both shrub species, respiration rates of very fine (<1.0 mm diameter) roots were significantly greater than those of fine (1–2 mm diameter) roots, and root respiration decreased as soil water decreased. Because specific root length was not significantly affected by CO2 and because field minirhizotron measurements of root production were not significantly different, we infer that root growth at the NDFF has not increased with elevated CO2. Furthermore, other studies at the NDFF have shown increased nutrient availability under elevated CO2, which reduces the need for roots to increase scavenging for nutrients. Thus, we conclude that A. dumosa and L. tridentata root systems have not increased in size or activity, and increased shoot production observed under elevated CO2 for these species does not appear to be constrained by the plant's root growth or activity.
Role of six European tree species and land‐use legacy for nitrogen and water budgets in forests
Authors: CHRISTIANSEN JESPER RIIS , VESTERDAL LARS , CALLESEN INGEBORG , ELBERLING BO , SCHMIDT INGER KAPPEL , GUNDERSEN PER
Published: September 2009

Water and nutrient fluxes for single stands of different tree species have been reported in numerous studies, but comparative studies of nutrient and hydrological budgets of common European deciduous tree species are rare. Annual fluxes of water and inorganic nitrogen (N) were established in a 30‐year‐old common garden design with stands of common ash (Fraxinus excelsior), European beech (Fagus sylvatica L.), pedunculate oak (Quercus robur), small‐leaved lime (Tilia cordata Mill.), sycamore maple (Acer pseudoplatanus) and Norway spruce (Picea abies [L.] Karst.) replicated at two sites in Denmark, Mattrup and Vallø during 2 years. Mean annual percolation below the root zone (mm yr−1±SE, n=4) ranked in the following order: maple (351±38)>lime (284±32), oak (271±25), beech (257±30), ash (307±69)≫ spruce (75±24). There were few significant tree species effects on N fluxes. However, the annual mean N throughfall flux (kg N ha−1 yr−1±SE, n=4) for spruce (28±2) was significantly larger than for maple (12±1), beech (11±1) and oak (9±1) stands but not different from that of lime (15±3). Ash had a low mean annual inorganic N throughfall deposition of 9.1 kg ha−1, but was only present at Mattrup. Annual mean of inorganic N leaching (kg ha−1 yr−1±SE, n=4) did not differ significantly between species despite of contrasting tree species mean values; beech (25±9)>oak (16±10), spruce (15±8), lime (14±8)≫ maple (1.9±1), ash (2.0±1). The two sites had similar throughfall N fluxes, whereas the annual leaching of N was significantly higher at Mattrup than at Vallø. Accordingly, the sites differed in soil properties in relation to rates and dynamics of N cycling. We conclude that tree species affect the N cycle differently but the legacy of land use exerted a dominant control on the N cycle within the short‐term perspective (30 years) of these stands.
Associations of leaf miners and leaf gallers with island plants of different residency histories
Authors: Sugiura Shinji
Published: September 2009

Aim  Introduced plant species are less likely to be attacked by herbivores than are native plant species. Isolated oceanic islands provide an excellent model system for comparing the associations between herbivore species and plant species of different residency histories, namely endemic, indigenous (non‐endemic) or introduced (naturalized or cultivated) species. My aim was to test the prediction that, on isolated oceanic islands, introduced plant species have a lower tendency to have an association with insect herbivores than do endemic and indigenous plant species.

Location  Ogasawara (Bonin) Islands in the western Pacific Ocean.

Methods  I examined the presence/absence of leaf‐mining and leaf‐galling insect species on 71 endemic, 31 indigenous, 18 naturalized and 31 cultivated (introduced but not naturalized) species of woody plants from 2004 to 2008.

Results  Leaf‐mining insect species were found on 53.5%, 35.5%, 11.1% and 16.1% and leaf‐galling species were found on 14.1%, 9.7%, 5.6% and 0% of endemic, indigenous, naturalized and cultivated plant species, respectively. Species of Lepidoptera (moths) and Hemiptera (primarily psyllids) comprised the dominant types of leaf miners and leaf gallers, respectively.

Main conclusions  The incidence of leaf miners and leaf gallers differed as a function of residency history of the plant species. Introduced (naturalized and cultivated) species were less frequently associated with leaf miners and leaf gallers than were native (endemic and indigenous) species, indicating that the leaf‐mining and leaf‐galling insect species, most of which feed on leaves of a particular native plant genus (i.e. they show oligophagy), have not yet begun to utilize most introduced plant species.
Geographic limits of a clonal population of wheat yellow rust in the Mediterranean region
Authors: BAHRI B. , LECONTE M. , OUFFROUKH A. , DE VALLAVIEILLE‐POPE C. , ENJALBERT J.
Published: September 2009

Most plant pathogens present complex life cycles, in which the clonal reproduction may impede the delimitation of population entities. By studying the genetic structure of the wheat yellow rust caused by Puccinia striiformis f.sp. tritici (PST), we highlighted difficulties impeding population delimitation in highly clonal species. Despite the high dispersal potential of PST, southern France isolates were shown to be divergent from a northwestern European population. A 2‐year survey was performed in the Mediterranean region to assess the geographic distribution of southern isolates: 453 isolates collected in 11 countries were genotyped using 15 simple sequence repeat markers. A subsample was analysed for virulence against 23 resistance genes. The dominant strain in the western Mediterranean region was further studied with amplified fragment length polymorphism markers to test for a geographic substructure. Both ‘individual’‐ and ‘population’‐centred analyses of polymorphism markers revealed two south‐specific groups: a predominant group, with a broad variability and a wide distribution in both western and eastern Mediterranean countries, and a minor group in the western Mediterranean. The east–west gradient of genetic diversity suggested gene flow from the Middle East with subsequent founder effects and genetic divergence, and demonstrated the local survival of a western Mediterranean population. The high frequency of the resistance gene Yr8 observed in cultivars from Tunisia and Algeria may contribute to maintain the north/south structure observed in France. In addition to migration and local adaptation, the dynamics of clonal lineage diversification and replacement should be considered to define population entities in strongly clonal species.
Comparison of contemporary mating patterns in continuous and fragmented Eucalyptus globulus native forests
Authors: MIMURA MAKIKO , BARBOUR ROBERT C. , POTTS BRAD M. , VAILLANCOURT RENÉ E. , WATANABE KAZUO N.
Published: September 2009

While habitat fragmentation is a central issue in forest conservation studies in the face of broad‐scale anthropogenic changes to the environment, its effects on contemporary mating patterns remain controversial. This is partly because of the inherent variation in mating patterns which may exist within species and the fact that few studies have replication at the landscape level. To study the effect of forest fragmentation on contemporary mating patterns, including effective pollen dispersal, we compared four native populations of the Australian forest tree, Eucalyptus globulus. We used six microsatellite markers to genotype 1289 open‐pollinated offspring from paired fragmented and continuous populations on the island of Tasmania and in Victoria on mainland Australia. The mating patterns in the two continuous populations were similar, despite large differences in population density. In contrast, the two fragmented populations were variable and idiosyncratic in their mating patterns, particularly in their pollen dispersal kernels. The continuous populations showed relatively high outcrossing rates (86–89%) and low correlated paternity (0.03–0.06) compared with the fragmented populations (65–79% and 0.12–0.20 respectively). A greater proportion of trees contributed to reproduction in the fragmented (de/d≥ 0.5) compared with the continuous populations (de/d = 0.03–0.04). Despite significant inbreeding in the offspring of the fragmented populations, there was little evidence of loss of genetic diversity. It is argued that enhanced medium‐ and long‐distance dispersal in fragmented landscapes may act to partly buffer the remnant populations from the negative effects of inbreeding and drift.
Female philopatry in coastal basins and male dispersion across the North Atlantic in a highly mobile marine species, the sperm whale (Physeter macrocephalus)
Authors: ENGELHAUPT DANIEL , RUS HOELZEL A. , NICHOLSON COLIN , FRANTZIS ALEXANDROS , MESNICK SARAH , GERO SHANE , WHITEHEAD HAL , RENDELL LUKE , MILLER PATRICK , DE STEFANIS RENAUD , CAÑADAS ANA , AIROLDI SABINA , MIGNUCCI‐GIANNONI ANTONIO A.
Published: September 2009

The mechanisms that determine population structure in highly mobile marine species are poorly understood, but useful towards understanding the evolution of diversity, and essential for effective conservation and management. In this study, we compare putative sperm whale populations located in the Gulf of Mexico, western North Atlantic, Mediterranean Sea and North Sea using mtDNA control region sequence data and 16 polymorphic microsatellite loci. The Gulf of Mexico, western North Atlantic and North Sea populations each possessed similar low levels of haplotype and nucleotide diversity at the mtDNA locus, while the Mediterranean Sea population showed no detectable mtDNA diversity. Mitochondrial DNA results showed significant differentiation between all populations, while microsatellites showed significant differentiation only for comparisons with the Mediterranean Sea, and at a much lower level than seen for mtDNA. Samples from either side of the North Atlantic in coastal waters showed no differentiation for mtDNA, while North Atlantic samples from just outside the Gulf of Mexico (the western North Atlantic sample) were highly differentiated from samples within the Gulf at this locus. Our analyses indicate a previously unknown fidelity of females to coastal basins either side of the North Atlantic, and suggest the movement of males among these populations for breeding.
Genetic variation and local adaptation at a cheatgrass (Bromus tectorum) invasion edge in western Nevada
Authors: LEGER ELIZABETH A. , ESPELAND ERIN K. , MERRILL KEITH R. , MEYER SUSAN E.
Published: September 2009

Cheatgrass (Bromus tectorum) is an invasive weed in western North America found primarily growing at elevations less than 2200 m. We asked whether cheatgrass is capable of becoming adapted to a marginal habitat, by investigating a population at a high elevation invasion edge. We used a combination of methods, including reciprocal field transplants, controlled environment studies and molecular analysis. High levels of SSR gene diversity (0.50 vs. 0.43) and comparable variation in phenotypic traits were observed at both the invasion edge and a low elevation, high‐density population. Three heterozygotes were observed in the edge population, which is unusual in this predominantly self‐pollinating plant. Plants from high elevations germinated more slowly in a growth chamber and had slower seedling growth rates. Survivorship was low at the edge (13%), compared with the low elevation site (55%), but surviving plants were of similar size and had equivalent reproductive output. Seed size positively affected survival and plant performance in the field and this trait was inherited. Emergence timing affected survival at the low elevation site and germination timing was also inherited. Local adaptation was seen in the low, rather than in the high elevation site, because of differential survival. While there was no evidence for local adaptation to the high elevation site observed in the field, family level and genotype‐level differences in traits that affected field performance, high genetic diversity at the invasion edge, and evidence of outcrossing in this highly selfing species indicates that the potential for adaptation to a marginal habitat exists within this population.
Concordant genetic breaks, identified by combining clustering and tessellation methods, in two co‐distributed alpine plant species
Authors: THIEL‐EGENTER CONNY , HOLDEREGGER ROLF , BRODBECK SABINE ,   INTRABIODIV CONSORTIUM, GUGERLI FELIX
Published: September 2009

Natural genetic breaks may indicate limitations to gene flow or the presence of contact zones of previously isolated populations. Molecular evidence suggests that genetic breaks have aggregated in distinct geographical areas. We propose a new application of well‐established statistical methods for analysing multilocus genetic data to identify intraspecific genetic breaks. The methodological approach combines Bayesian clustering with a spatially explicit maximum‐difference algorithm to visualize and quantify breaks between clusters. We used amplified fragment length polymorphism data of two co‐distributed, silicicolous alpine plant species, Geum montanum and Geum reptans, exhaustively sampled on a consistent, regular grid over their entire range of the European Alps and the Carpathians. We found a distinct and highly similar allocation of genetic breaks in both species. The pattern of breaks did not conform to scenarios of glacial refugial survival, alternatively in peripheral refugia or on nunataks, as expected because of the species’ ecologies (late‐successional low alpine vs. early‐successional high alpine). Our findings rather substantiated the postulate of a general pattern of genetic breaks in alpine plants and corresponded well with biogeographical regions formerly described. Our approach could serve as a tool not only for landscape genetics and comparative phylogeography, but also for floristics or faunistics to compare biogeographic with phylogeographic breaks.
Hydrogen sulphide protects H9c2 cells against chemical hypoxia‐induced injury
Authors: Chen Si‐Lin , Yang Chun‐Tao , Yang Zhan‐Li , Guo Rui‐Xian , Meng Jin‐Lan , Cui Yu , Lan Ai‐Ping , Chen Pei‐Xi , Feng Jian‐Qiang
Published: September 2009

1. The aim of the present study was to investigate the effect of hydrogen sulphide (H2S) on cobalt chloride (CoCl2)‐induced injury in H9c2 embryonic rat cardiac cells.

2. After 36 h incubation in the presence of 600 μmol/L CoCl2, reduced cell viability of H9c2 cells was observed, as well as the induction of apoptosis. In addition, CoCl2 (600 μmol/L) enhanced the production of reactive oxygen species (ROS) and the expression of cleaved caspase 3, induced a loss of mitochondrial membrane potential (MMP) and decreased reduced glutathione (GSH) production. These results suggest that CoCl2 induces similar responses to hypoxia/ischaemia.

3. Pretreatment of cells with 400 μmol/L NaHS (a H2S donor) for 30 min prior to exposure to CoCl2 (600 μmol/L) significantly protected H9c2 cells against CoCl2‐induced injury. Specifically, increased cell viability and decreased apoptosis were observed. In addition, NaHS pretreatment blocked the CoCl2‐induced increases in ROS production and cleaved caspase 3 expression, as well as the decreases in GSH production and loss of MMP.

4. Pretreatment of cells with 2000 μmol/L N‐acetylcysteine (NAC), a ROS scavenger, for 1 h prior to CoCl2 exposure significantly protected H9c2 cells against CoCl2‐induced injury, specifically enhancing cell viability, decreasing ROS production and preventing loss of MMP.

5. The findings of the present study suggest that H2S protects H9c2 cells against CoCl2‐induced injury by suppressing oxidative stress and caspase 3 activation.