bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of rooting volume and nutrient availability as an alternative explanation for root self/non‐self discrimination
Authors: HESS LINDE , DE KROON HANS 
Published: January 2007

Abstract

An increasing number of studies have shown that plants produce more root mass when sharing rooting space with an intraspecific neighbour as compared with plants growing alone. This so‐called self/non‐self discrimination has been suggested as a mechanism by which plants may prevent wasteful competition with their own roots and enhance their competitive ability for nutrients with roots of neighbouring plants. The overproduction of root biomass is said to result in a ‘tragedy of the commons’, because it appears to occur at the expense of reproductive biomass.
Studies on self/non‐self root discrimination have commonly used a split‐root design to distinguish self from non‐self competition, while keeping the total amount of nutrients available per plant the same. This design has recently been criticized because the rooting volume differs between treatments.
Here, we use three general hypotheses to explain the published results without invoking the mechanism of self/non‐self discrimination. The hypotheses propose that differences in root mass are due to differences in rooting volume, and differences in nutrient availability determine whole plant growth. More root mass without more growth results in less reproductive biomass.
A reanalysis of the results of root self/non‐self discrimination confirms these hypotheses. Root overproduction in the presence of another plant, as found in nearly all studies, is consistent with effects of a larger soil volume available to these plants as compared with plants growing alone. Under the same total nutrient availability, total plant weight was the same or higher when more roots were produced. Inevitably, a larger root production with the same total biomass implies that less reproductive biomass is produced.
Although our analysis can explain most of the results of the split‐root experiments, we cannot rule out the possibility that self/non‐self root discrimination did take place. We discuss a limited set of experiments for which volume effects cannot explain the results, suggesting, in fact, that direct self/non‐self root interactions have operated. We suggest experimental designs that can demonstrate their ecological significance in the future.
We conclude that there is ample evidence that plants can sense the volume of available rooting space, and a limited number of studies on individual roots show that plant roots may sense the identity of neighbouring roots and respond accordingly. The significance of these responses for whole plant growth and reproduction in relation to well‐known resource competition effects is yet largely unknown and in urgent need of further study.
Carbohydrate storage enhances seedling shade and stress tolerance in a neotropical forest
Authors: MYERS JONATHAN A. , KITAJIMA KAORU 
Published: January 2007

SummaryTo survive in forest understoreys, seedlings must depend on carbohydrate reserves when they experience negative carbon balance imposed by occasional light reduction and tissue loss to herbivores and diseases. We present the first experimental evidence in support of this hypothesis, using seven woody neotropical species.We transplanted seedlings that had recently expanded their first photosynthetic cotyledon or leaf to the forest understorey (1% of full sun) and quantified initial biomass and total non‐structural carbohydrate (TNC) in stems, roots and storage cotyledons. We then randomly assigned seedlings to control and two stress treatments: light reduction (0.08% of full sun for 8 weeks) and complete defoliation.First‐year survival of control seedlings, a comparative measure of shade tolerance, differed widely among species. The two stress treatments reduced survival and relative growth rates (RGR) of all species. Shade‐tolerant species were little impacted by the stress treatments, whereas the two least shade‐tolerant species experienced 100% mortality.In all treatments, 8‐week and first‐year survival was positively correlated with initial TNC pool size in stems and roots. By contrast, survival was generally not correlated with initial TNC concentration in any organ, TNC pools in cotyledons, seed mass or seedling biomass.TNC in stems and roots, but not in cotyledons, decreased in response to light reduction and defoliation over 8 weeks. Leaf area recovery of defoliated seedlings was positively correlated with initial TNC pools in stems and roots.First‐year survival in each treatment was negatively correlated with 0–8 week RGR of control seedlings, suggesting higher stress tolerance of species with inherently slow growth rates in shade. RGR of control seedlings from 0 to 8 weeks was negatively correlated with initial TNC pools, but not concentrations, in stems and roots. After 8 weeks, RGR was positive for all species, without clear relationships with survival or TNC.We conclude that carbohydrate storage in stems and roots enhances long‐term survival in shade by enabling seedlings to cope with periods of biotic and abiotic stress. Carbohydrate storage is a key functional trait that can explain species differences in growth and survival that lead to species coexistence through niche assembly processes and life‐history trade‐offs.
Phytochrome mediates germination responses to multiple seasonal cues
Authors: DONOHUE KATHLEEN , HESCHEL M. SHANE , CHIANG GEORGE C.K. , BUTLER COLLEEN M. , BARUA DEEPAK 
Published: January 2007

ABSTRACTWe identified a new role of phytochrome in mediating germination responses to seasonal cues and thereby identified for the first time a gene involved in maternal environmental effects on germination. We examined the germination responses of a mutant, hy2‐1, which is deficient in the phytochrome chromophore. The background genotype, Landsberg erecta (Ler), lacked dormancy in most treatments, while hy2‐1 required cold stratification for germination in a manner that resembled a more dormant ecotype, Columbia (Col). Unlike Col, hy2‐1 was not induced into dormancy by warm stratification. Therefore, the down‐regulation of phytochrome‐mediated germination pathways results in sensitivity to cold, but we found no evidence that reduced phytochrome activity enables the warm‐induction of dormancy. Cool temperatures during seed maturation induced dormancy. The hy2‐1 mutants did not overcome this dormancy, indicating that phytochrome‐mediated pathways are required to break cold‐induced dormancy. Ler did not respond to post‐stratification temperature, but hy2‐1 did respond, suggesting phytochrome pathways are involved in germination responses to temperature. In summary, phytochromes mediate dormancy and germination responses to seasonal cues experienced both during seed maturation and after dispersal. Phytochromes therefore appear to be involved in mediating seasonal germination timing, a trait of great ecological importance and one that is under strong natural selection.
Biophysical properties and functional significance of stem water storage tissues in Neotropical savanna trees
Authors: SCHOLZ FABIAN G. , BUCCI SANDRA J. , GOLDSTEIN GUILLERMO , MEINZER FREDERICK C. , FRANCO AUGUSTO C. , MIRALLES‐WILHELM FERNANDO 
Published: January 2007

ABSTRACTBiophysical characteristics of sapwood and outer parenchyma water storage compartments were studied in stems of eight dominant Brazilian Cerrado tree species to assess the impact of differences in tissue capacitance on whole‐plant water relations. The rate of decline in tissue water potential with relative water content (RWC) was greater in the outer parenchyma than in the sapwood for most of the species, resulting in tissue‐and species‐specific differences in capacitance. Sapwood capacitance on a tissue volume basis ranged from 40 to 160 kg m−3 MPa−1, whereas outer parenchyma capacitance ranged from 25 to only 60 kg m−3 MPa−1. In addition, osmotic potentials at full turgor and at the turgor loss point were more negative for the outer parenchyma compared with the sapwood, and the maximum bulk elastic modulus was higher for the outer parenchyma than for the sapwood. Sapwood capacitance decreased linearly with increasing sapwood density across species, but there was no significant correlation between outer parenchyma capacitance and tissue density. Midday leaf water potential, the total hydraulic conductance of the soil/leaf pathway and stomatal conductance to water vapour (gs) all increased with stem volumetric capacitance, or with the relative contribution of stored water to total daily transpiration. However, the difference between the pre‐dawn water potential of non‐transpiring leaves and the weighted average soil water potential, a measure of the water potential disequilibrium between the plant and soil, increased asymptotically with total stem capacitance across species, implying that overnight recharge of water storage compartments was incomplete in species with greater capacitance. Overall, stem capacitance contributes to homeostasis in the diurnal and seasonal water balance of Cerrado trees.
Long‐term effects of leisure time physical activity on risk of insulin resistance and impaired glucose tolerance, allowing for body weight history, in Danish men
Authors: Berentzen T. , Petersen L. , Pedersen O. , Black E. , Astrup A. , Sørensen T. I. A. 
Published: January 2007

AbstractAims To determine if the level of leisure time physical activity (LTPA) in young adulthood in obese and non‐obese men reduces the risk of insulin resistance (IR) and impaired glucose tolerance (IGT) in middle age, and if such an effect is explained by the current level of LTPA, or by the body mass index (BMI) history preceding and subsequent to the assessment of LTPA.Methods Longitudinal study of groups of obese and randomly selected non‐obese men identified at around age 19, and re‐examined at mean ages of 32, 44 and 51. BMI was measured at all four examinations. LTPA was assessed by self‐administrated questionnaires at the last three examinations. IR and the presence of IGT was determined by an oral glucose tolerance test at the last examination.Results LTPA in young adulthood reduced the risk of IR and IGT in middle age throughout the range of BMI. Adjustment for the BMI history preceding and subsequent to the assessment of LTPA attenuated the association with IR and IGT, but active men remained at low risk of IR and IGT. Adjustment for subsequent and current levels of LTPA, smoking habits, alcohol intake, educational level and family history of diabetes had no notable influence on the results.Conclusion LTPA appears to reduce the risk of IR and IGT, an effect which is not explained by the current level of physical activity, and only partially explained by the BMI history preceding and subsequent to the assessment of LTPA.
Stability of an empirical psychosocial taxonomy across type of diabetes and treatment
Authors: Nouwen A. , Breton M.‐C. , Urquhart Law G. , Descôteaux J. 
Published: January 2007

AbstractAims  The aims of the study were (i) to examine whether an empirical psychosocial taxonomy, based on key diabetes‐related variables, is independent of type of diabetes and treatment, and (ii) to further establish the external validation of the taxonomy.Methods  In a cross‐sectional study, 82 patients with Type 1 and 86 patients with Type 2 diabetes mellitus were assigned to one of three psychosocial patient profiles based on their Multidimensional Diabetes Questionnaire (MDQ) scores. General psychological and diabetes‐specific measures were obtained through self‐report and HbA1c was measured.Results  Equal proportions of Type 1 and Type 2 patients, and of patients using insulin and oral medication/diet only were classified within each of the three psychosocial profiles. External validation confirmed the validity and distinctiveness of the patients’ profiles. The patient profiles were independent of demographic variables, body mass index, duration of diabetes, complexity of treatment, number of complications, social desirability, and major stress levels.Conclusions  The Psychosocial Taxonomy for Patients with Diabetes provides a new way to categorize individuals who may have more in common than just their type of diabetes and/or its treatment and can help target interventions to individual patients’ needs.
Non‐alcoholic fatty liver disease, the metabolic syndrome and the risk of cardiovascular disease: the plot thickens
Authors: Targher G. 
Published: January 2007

AbstractNon‐alcoholic fatty liver disease (NAFLD) affects a substantial proportion of the general population and is frequently associated with many features of the metabolic syndrome (MetS). Currently, the importance of NAFLD and its relationship with the MetS is being increasingly recognized, and this has stimulated an interest in the possible role of NAFLD in the development of atherosclerosis. Recent studies have reported the association of NAFLD with multiple classical and non‐classical risk factors for cardiovascular disease (CVD). Moreover, there is a strong association between the severity of liver histopathology in NAFLD patients and greater carotid artery intima‐media thickness and plaque, and lower endothelial flow‐mediated vasodilation (as markers of subclinical atherosclerosis) independent of obesity and other MetS components. Finally, it has recently been demonstrated that NAFLD is associated with an increased risk of all‐cause death and predicts future CVD events independently of other prognostic factors, including MetS components. Overall, therefore, the evidence from these recent studies strongly emphasizes the importance of assessing the global CVD risk in patients with NAFLD. Moreover, these novel findings suggest a more complex picture and raise the possibility that NAFLD, as a component of the MetS, might not only be a marker but also an early mediator of CVD.
Bone loss in diabetic patients with chronic kidney disease
Authors: Rigalleau V. , Lasseur C. , Raffaitin C. , Perlemoine C. , Barthe N. , Chauveau P. , Aparicio M. , Combe C. , Gin H. 
Published: January 2007

AbstractObjective  We investigated whether loss of bone is detectable during follow‐up of diabetic patients with chronic kidney disease (CKD).Research design and methods  In 40 initially non‐dialysed diabetic patients with CKD (isotopic glomerular filtration rate < 60 ml/min/1.73 m2 or albumin excretion rate > 30 mg/24 h), body composition (DEXA scan) and glomerular filtration rate (GFR determined from 51Cr‐EDTA clearance) were measured at a 2‐year interval, and compared by paired t‐tests.Results  The 40 patients, mainly with Type 2 diabetes (n = 28), were men (n = 28), aged 65 ± 11 years, with diabetes duration 18 ± 11 years. GFR was initially 38.0 (range 8–89) ml/min/1.73 m2. CKD progressed during follow‐up: eight started haemodialysis and GFR declined in the 32 others (P < 0.05 vs. initial). T‐scores for total body (initial −0.61 ± 1.11, final −1.11 ± 1.40; P < 0.001) and femoral neck (initial −1.88 ± 0.15, final −2.07 ± 0.15; P < 0.05) declined. Ten patients were osteopaenic at baseline (no osteoporosis), whereas most were osteopaenic (n = 21, P < 0.05) and five were osteoporotic at final assessment. The 16 patients who became osteopaenic or osteoporotic during follow‐up did not differ from the others for the type of diabetes, age, GFR, albumin excretion rate, HbA1c, GFR reduction and the requirement for dialysis during follow‐up. They were all men (P < 0.01 by chi‐squared test), with reduced initial total body T‐score (−1.20 ± 0.82, others −0.32 ± 1.13; P < 0.05) and a lower body mass index (24.6 ± 4.3; others 27.7 ± 4.3; P < 0.05).Conclusion  Bone loss, especially in the femoral neck, is progressive in diabetic patients with CKD.
Social security pensionable ages in OECD countries: 1949‐2035
Authors: Turner John 
Published: January 2007

Abstract This paper examines the pensionable or early retirement age in social security in 23 OECD countries over the years 1949‐2035. The policies for future years are those in current law, with some not being fully effective until 2035. The paper documents a pattern of decreasing pensionable ages that reversed in the 1990s, with many countries raising pensionable ages since the beginning of that decade, though generally with future effective dates. Pensionable‐age policy provides insight into broader issues in social policy, such as whether social policies across countries have converged over time. The paper also examines the time pattern in the movement toward gender equality in social programmes.
Political Opposition and the European Union
Authors: Mair Peter 
Published: January 2007

AbstractThis paper applies categories developed in the classic literature on political opposition to the developing European Union. It is clear that the EU has never developed the third great milestone identified by Dahl in his analysis of the path to democratic institutions. That is, we still lack the capacity to organize opposition within the European polity. This failure to allow for opposition within the polity is likely to lead either (a) to the elimination of opposition altogether, or (b) to the mobilization of an opposition of principle against the EU polity. This problem is also beginning to reach down into the domestic sphere, in that the growing weight of the EU, through its indirect impact on national politics, helps to encourage domestic democratic deficits, hence limiting the scope for classical opposition at the national level. Here too, then, we might expect to see either the elimination of opposition or the mobilization of a new – perhaps populist – opposition of principle.
Manipulating Rules, Contesting Solutions: Europeanization and the Politics of Restructuring Olympic Airways
Authors: Featherstone Kevin , Papadimitriou Dimitris 
Published: January 2007

AbstractIn recent years much debate has been generated over the reshaping of the European airline industry and the restructuring of many of the heavily indebted national flag-carriers across the European Union. The European Commission has sought to orchestrate this reform process by the gradual break up of monopolies in air travel and its associated services and a much tighter policing of state aid practices. The EU's liberalizing agenda in air transport, however, has met with strong domestic opposition in the member states. Nowhere else has the resistance to reform been stronger than in Greece, where for a decade successive attempts to restructure or privatize Olympic Airways have yielded very limited success. By focusing, in particular, on the initiative of the Greek government in 2003 to create a new ‘Olympic Airlines’, the article examines how domestic pressures prompted the Greek government to shift away from cooperation with the Commission and invite conflict. The Greek government lost an ECJ case and both Athens and the Commission were left with a sub-optimal outcome. By linking the narrative to the conceptual literature on Europeanization and compliance, the article addresses a number of themes including: the contestation of European competition rules and the ability of national governments to manipulate them, policy entrepreneurship and complex problem-solving, as well as the Commission's role as a stimulus, but potentially also an obstacle to domestic reform.
Global Markets and National Regulation: The Protection of Shareholder Interests in Germany and Italy
Authors: McCann Dermot 
Published: January 2007

AbstractGlobal market integration is widely perceived as presenting a major challenge to the sustainability of many national economic regulatory systems. There is far less agreement, however, about precisely how these pressures feed into the politics of reform and reshape national public policy. This article will seek to cast light on this relationship by identifying four influential ‘models of linkage’ between global pressures and regulatory change. It will then comparatively assess their capacity to elucidate the progress of shareholder protection reform in Germany and Italy. While no single model proves fully satisfactory, it will be argued that the weaknesses of two of them can be largely overcome through a process of refinement and integration.
Evaluation of Quantitative Magnetic Resonance Imaging Contrasts in MRI‐Negative Refractory Focal Epilepsy
Authors: Salmenpera Tuuli M. , Symms Mark R. , Rugg‐Gunn Fergus J. , Boulby Philip A. , Free Samantha L. , Barker Gareth J. , Yousry Tarek A. , Duncan John S. 
Published: January 2007

Summary:  Purpose: Conventional optimal MRI is unremarkable in 20%–30% of patients with intractable focal epilepsy. These MRI‐negative patients are the most challenging in surgical programs. Our aim was to evaluate the yield and utility of quantitative MRI with novel contrasts in MRI‐negative patients with refractory focal epilepsy, who were potential surgical candidates. Methods: Ninety‐three consecutive potential surgical candidates with refractory focal epilepsy, 44 with temporal lobe epilepsy, and 49 with frontal lobe epilepsy as determined with ictal scalp video‐EEG; and normal optimal conventional MRI, including hippocampal volumes and T2 measures were investigated with quantitative MRI contrasts. The contrasts comprised fast fluid attenuated inversion recovery based T2 measurement (FFT2), double inversion recovery (DIR), magnetization transfer ratio (MTR), and voxel‐based morphometry of gray matter (VBM). Voxel‐based analyses of whole brain data were used to compare each patient with a control group. Results: In patients with a putative single focus on scalp video‐EEG telemetry, 16% had concordant FFT2 abnormalities, as did 16% with DIR, 5% with MTR and 9% with VBM. The greatest agreement in the localization of abnormalities was between FFT2 and DIR. Altogether, 31% patients had a focal abnormality with at least one contrast in the lobe of seizure onset. Signal changes outside the lobe of the putative focus were found with FFT2 in 36% patients, with DIR in 42%, with MTR in 6% and with VBM in 7%. Discussion: Quantitative analysis of MRI contrasts had a low yield of identifying focal abnormalities concordant with putative epileptic foci in patients with unremarkable conventional MRI. Specificity was low for FFT2 and DIR. With the low specificity, data must be interpreted with caution, but in some patients may assist in creating a hypothesis for testing with intracranial electrodes.