bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in free radical generation and antioxidant capacity during ultramarathon foot race
Authors: Skenderi K. P. , Tsironi M. , Lazaropoulou C. , Anastasiou C. A. , Matalas A‐L. , Kanavaki I. , Thalmann M. , Goussetis E. , Papassotiriou I. , Chrousos G. P. 
Published: February 2008

ABSTRACTBackground  Exhaustive exercise has been implicated in the generation of reactive oxygen species, resulting in oxidative stress. We studied the effect of a long‐distance, endurance exercise on oxidative stress parameters in athletes who participated in the ultramarathon race Spartathlon (246 km).Materials and methods  This study included 18 runners (16 men and 2 women) aged 42·8 ± 1·4 years. Blood samples were obtained 24 h before (prerace), at the end (postrace) and 48 h after the end of the race (48 h postrace). We measured oxidative stress indices, including red cell glutathione, malonyldialdehyde and 8‐iso‐prostaglandin F2a, as well as the total antioxidant capacity.Results  8‐Iso‐prostaglandin F2a level increased significantly at the end of the race, compared to prerace levels (up to 914·7 ± 61·4 pg mL−1 from 197·6 ± 8·4 pg mL−1), and remained 2·5‐fold increased over the baseline 48 h after the race (532·0 ± 54·2 pg mL−1, P < 0·000). The total antioxidant capacity of the athletes increased from a baseline of 289·6 ± 9·0 µmol L−1 to 358·7 ± 11·0 µmol L−1 immediately after the race and remained elevated 48 h later (350·6 ± 7·6 µmol L−1) (P < 0·001).Conclusions  Prolonged exercise induces a marked response of oxidative stress biomarkers, which in part is compensated by serum ability to scavenge free radicals. Whether these changes have long‐term negative effects in the organism needs further investigation.
Improvement of glycaemic control by nateglinide decreases systolic blood pressure in drug‐naive patients with type 2 diabetes
Authors: González‐Clemente J.‐M. ,   on behalf of the Spanish Nateglinide Study Group
Published: February 2008

ABSTRACTBackground  It has been speculated that oral hypoglycaemic agents that block K‐ATP channels could potentially increase blood pressure by blocking such channels in vascular myocytes. No information about this issue exists regarding nateglinide.Design  A multicentre, double‐blind, placebo‐controlled, randomized trial was conducted in 109 drug‐naive 30‐ to 75‐year‐old patients with type 2 diabetes and < 5 years of diabetes diagnosis, who are not taking antihypertensive drugs. These patients were assigned to receive placebo or fixed doses of nateglinide (120 mg before each main meal: breakfast, lunch and dinner) and evaluated at weeks 0 and 12 for (i) body mass index and blood pressure; (ii) standard laboratory tests, including haemoglobin A1c (HbA1c) and fasting plasma glucose; and (iii) incremental area under the curve for glucose and C‐peptide after a standardized liquid breakfast challenge, homeostasis model assessment (HOMA)‐B% (as surrogate of β‐cell activity) and HOMA‐S% (as surrogate of insulin sensitivity).Results  At the end of the follow‐up period, patients in the nateglinide group (n = 55), compared to patients in the placebo group (n = 54), showed lower values of HbA1c (6·7 ± 0·6 vs. 7·2 ± 0·7%, respectively; P < 0·001), fasting plasma glucose (7·9 ± 2·1 vs. 8·5 ± 2·0 mmol L−1; P = 0·023) and systolic blood pressure (125·3 ± 15·4 vs. 129·3 ± 18·7 mmHg; P = 0·015), and higher values of HOMA‐B%[75·7 (51·8–99·4) vs. 57·7 (42·2–83·4); P = 0·033]. A positive correlation was found between changes in HbA1c and systolic blood pressure in the nateglinide group (r = 0·355, P = 0·011).Conclusions  In drug‐naive patients with type 2 diabetes, the improvement in glycaemic control with nateglinide is associated with a decrease in systolic blood pressure.
Microscale vegetation‐soil feedback boosts hysteresis in a regional vegetation–climate system
Authors: JANSSEN RUUD H. H. , MEINDERS MARCEL B. J. , Van NES EGBERT H. , SCHEFFER MARTEN 
Published: February 2008

AbstractIt has been hypothesized that a positive feedback between vegetation cover and monsoon circulation may lead to the existence of two alternative stable states in the Sahara region: a vegetated state with moderate precipitation and a desert state with low precipitation. This could explain the sudden onset of desertification in the region about 5000 years ago. However, other models suggest that the effect of vegetation on the precipitation may be insufficient to produce this behavior. Here, we show that inclusion of the microscale feedback between soil and vegetation in the model greatly amplifies the nonlinearity, causing alternative stable states and considerable hysteresis even if the effect of vegetation on precipitation is moderate. On the other hand, our analysis suggests that self‐organized vegetation patterns known from models that only focus at the microscale plant–soil feedback will be limited to a narrower range of conditions due to the regional scale climate‐feedback. This implies that in monsoon areas such as the Western Sahara self‐organized vegetation patterns are predicted to be less common than in areas without monsoon circulation such as Central Australia.
Sensitivity of organic matter decomposition to warming varies with its quality
Authors: CONANT RICHARD T. , DRIJBER RHAE A. , HADDIX MICHELLE L. , PARTON WILLIAM J. , PAUL ELDOR A. , PLANTE ALAIN F. , SIX JOHAN , STEINWEG J. MEGAN 
Published: February 2008

AbstractThe relationship between organic matter (OM) lability and temperature sensitivity is disputed, with recent observations suggesting that responses of relatively more resistant OM to increased temperature could be greater than, equivalent to, or less than responses of relatively more labile OM. This lack of clear understanding limits the ability to forecast carbon (C) cycle responses to temperature changes. Here, we derive a novel approach (denoted Q10−q) that accounts for changes in OM quality during decomposition and use it to analyze data from three independent sources. Results from new laboratory soil incubations (labile Q10−q=2.1 ± 0.2; more resistant Q10−q=3.8 ± 0.3) and reanalysis of data from other soil incubations reported in the literature (labile Q10−q=2.3; more resistant Q10−q=3.3) demonstrate that temperature sensitivity of soil OM decomposition increases with decreasing soil OM lability. Analysis of data from a cross‐site, field litter bag decomposition study (labile Q10−q=3.3 ± 0.2; resistant Q10−q=4.9 ± 0.2) shows that litter OM follows the same pattern, with greater temperature sensitivity for more resistant litter OM. Furthermore, the initial response of cultivated soils, presumably containing less labile soil OM (Q10−q=2.4 ± 0.3) was greater than that for undisturbed grassland soils (Q10−q=1.7 ± 0.1). Soil C losses estimated using this approach will differ from previous estimates as a function of the magnitude of the temperature increase and the proportion of whole soil OM comprised of compounds sensitive to temperature over that temperature range. It is likely that increased temperature has already prompted release of significant amounts of C to the atmosphere as CO2. Our results indicate that future losses of litter and soil C may be even greater than previously supposed.
An integrated greenhouse gas assessment of an alternative to slash‐and‐burn agriculture in eastern Amazonia
Authors: DAVIDSON ERIC A. , De ABREU SÁ TATIANA DEANE , REIS CARVALHO CLAUDIO J. , De OLIVEIRA FIGUEIREDO RICARDO , KATO MARIA do SOCORRO A. , KATO OSVALDO R. , ISHIDA FRANÇOISE YOKO 
Published: February 2008

AbstractFires set for slash‐and‐burn agriculture contribute to the current unsustainable accumulation of atmospheric greenhouse gases, and they also deplete the soil of essential nutrients, which compromises agricultural sustainability at local scales. Integrated assessments of greenhouse gas emissions have compared intensive cropping systems in industrialized countries, but such assessments have not been applied to common cropping systems of smallholder farmers in developing countries. We report an integrated assessment of greenhouse gas emissions in slash‐and‐burn agriculture and an alternative chop‐and‐mulch system in the Amazon Basin. The soil consumed atmospheric methane (CH4) under slash‐and‐burn treatment and became a net emitter of CH4 to the atmosphere under the mulch treatment. Mulching also caused about a 50% increase in soil emissions of nitric oxide and nitrous oxide and required greater use of fertilizer and fuel for farm machinery. Despite these significantly higher emissions of greenhouse gases during the cropping phase under the alternative chop‐and‐mulch system, calculated pyrogenic emissions in the slash‐and‐burn system were much larger, especially for CH4. The global warming potential CO2‐equivalent emissions calculated for the entire crop cycles were at least five times lower in chop‐and‐mulch compared with slash‐and‐burn. The crop yields were similar for the two systems. While economic and logistical considerations remain to be worked out for alternatives to slash‐and‐burn, these results demonstrate a potential ‘win‐win’ strategy for maintaining soil fertility and reducing net greenhouse gas emissions, thus simultaneously contributing to sustainability at both spatial scales.
Psychosocial risk factors for work‐related musculoskeletal disorders of the lower‐back among long‐haul international female flight attendants
Authors: Lee Hyeonkyeong , Wilbur JoEllen , Kim Mi Ja , Miller Arlene M. 
Published: February 2008

AbstractTitle. Psychosocial risk factors for work‐related musculoskeletal disorders of the lower‐back among long‐haul international female flight attendantsAim. This paper is a report of a study to examine the relationships between work‐related psychosocial factors and lower‐back work‐related musculoskeletal disorders among long‐haul international female flight attendants.Background. Recent attention has focused on the influence of work‐related psychosocial factors on work‐related musculoskeletal disorders. To date, however, little is known about the influence of psychosocial factors at work on lower back work‐related musculoskeletal disorders in female flight attendants.Method. A cross‐sectional, mailed survey was conducted in 2004 with flight attendants in one major airline who were randomly selected from a union membership list. The work‐related psychosocial factors included psychological job demand, decision latitude, social support, job insecurity, and external environmental concerns. Physical load was defined by overall strenuousness across 41 job tasks and measured by a 4‐point scale of strenuousness. Lower‐back work‐related musculoskeletal disorders were defined as lower‐back symptoms that occurred at least once a month or lasted at least 1 week in the past year and caused at least moderate pain.Findings. The flight attendants with lower back work‐related musculoskeletal disorders, compared with those without lower‐back work‐related musculoskeletal disorders, had higher perceived psychological job demands, job insecurity, and physical load. After controlling for physical load and personal factors, high job insecurity significantly increased the risk for lower‐back work‐related musculoskeletal disorders.Conclusion. Occupational health nurses in the airline industry should be cognizant of the importance of assessing the influence of both job tasks and work‐related psychosocial factors on lower‐back work‐related musculoskeletal disorders.
Sedation of ventilated patients in intensive care units: relatives’ experiences
Authors: Dreyer Anne , Nortvedt Per 
Published: February 2008

AbstractTitle.  Sedation of ventilated patients in intensive care units: relatives’ experiences Aim.  This paper is a report of a study undertaken to explore the experiences of being relatives of ventilated and sedated patients in intensive care units.Background.  In the last few years, issues about medically‐induced sleep as part of intensive care unit treatment have focused on the appropriate level of medication. There are no studies of the impact of relatives on assessment of sedation levels, but studies of family participation in intensive care units show that relatives see their role as more important for the patient than nurses do.Method.  An explorative, descriptive design was adopted. In‐depth interviews were conducted with eight relatives of patients in 2003. The research question was: How do relatives experience having a close family member in a state of serious illness, being treated on a ventilator, and receiving medically induced sedation and pain relief? Kvale’s hermeneutical interpretation principles were used for data analysis.Results.  Relatives interviewed seemed to go through various phases that were specifically connected to the actual situation in the intensive care unit. The main characteristic of these phases was a pattern in which participants gradually became active caregivers for the patient. Relatives wanted to be included in discussions about treatment.Conclusion.  Relatives want to be included as caregivers when patients are under sedation in an intensive care unit. Relatives who know the patient can help evaluate the use of sedation and pain management to assist the nurses in giving the best care and the appropriate level of sedation for a patient.
Spatial match–mismatch in the Benguela upwelling zone: should we expect chlorophyll and sea‐surface temperature to predict marine predator distributions?
Authors: Grémillet David , Lewis Sue , Drapeau Laurent , Van Der Lingen Carl D. , Huggett Jenny A. , Coetzee Janet C. , Verheye Hans M. , Daunt Francis , Wanless Sarah , Ryan Peter G. 
Published: February 2008

Summary

Remote‐sensing measurements of marine primary productivity are widely used to predict the distribution and movements of marine top predators, despite the fact that predators do not feed directly on phytoplankton but several trophic levels higher up the food chain.
To test for potential links between primary productivity and top‐predator feeding hotspots, we assessed spatial match–mismatch across four trophic levels of the Benguela upwelling zone (south‐east Atlantic). The food chain studied consisted of phytoplankton, zooplankton (copepods), pelagic fish (anchovies and sardines) and two top predators (Cape gannets Morus capensis and human fisheries).
Remote‐sensing data of sea‐surface temperature (SST) and chlorophyll_a concentration were used as indices of phytoplankton abundance throughout the study area. Copepod biomass and pelagic fish density were determined during at‐sea surveys in the South African section of the Benguela using net tows and hydro‐acoustics, respectively. Seabird (Cape gannet) home ranges and foraging zones were assessed from two Namibian breeding colonies (Mercury and Ichaboe) and two South African colonies (Lambert's Bay and Malgas) using global positioning system (GPS) tracking. Industrial fishing for anchovies and sardines was investigated using South African landing statistics and logbooks.
Our spatial analyses revealed a strong match of seabird at‐sea habitat and zones of high primary productivity throughout the southern Benguela. Conversely, there was a marked spatial mismatch between copepods and pelagic fish, as well as between pelagic fish, seabirds and human fisheries: copepods were present in the southern Benguela but pelagic fish usually feeding upon them were located further east (Indian Ocean), outside of the Benguela sensu stricto. Consequently, the majority of these pelagic fish were out of reach for seabirds and fisheries confined to the southern Benguela.
Synthesis and applications. Our study demonstrates the impact of an ecosystem shift across one of the world's most productive marine ecosystems and highlights the limitations of using remote‐sensed patterns of primary productivity to interpret the foraging behaviour of marine top predators. These findings underline the importance of a better knowledge of food web spatial dynamics to support ecosystem‐based fisheries management and the conservation of marine top predators.
InvasiveAcer platanoidesinhibits native sapling growth in forest understorey communities
Authors: Galbraith‐Kent Shannon L. , Handel Steven N. 
Published: February 2008

SummaryOver three growing seasons, we tested how an invasive tree species (Acer platanoides) affected native plant growth in understorey communities of a suburban forest in central New Jersey, USA. We planted similar aged and sized saplings (≥ 0.25 m tall) into experimental plots identified with one of three treatments (0%, 25% and 50% of total stems are invasive species) and hypothesized native species would grow better in communities lacking invasive plants.There was a plant survival rate of 90% for the duration of the experiment, but in treatments where natives competed withA. platanoides, growth of native species was significantly less than in the purely native stand. In 2006, the mean height ofA. rubrumwas 110 cm (±4 SE) in communities with the highest proportion ofA. platanoides, while it was 149 cm (±7 SE) in the 0% invasive communities. Conversely,A. platanoidesgrew similarly in treatments where it comprised two different proportions and beneath both canopy types (i.e. invasive and native).Native saplings were 28% shorter beneath an invasive canopy (i.e.A. platanoides), compared with a native canopy. A striking interaction existed between community treatment and canopy type, as the invasive canopy had such a strong negative effect on native growth that the presence of invasive saplings was irrelevant. However, beneath a native canopy, the absence of invasive saplings significantly increased growth of native saplings. As the extent and rate of invasive proliferation often makes complete removal unrealistic, this study supports episodic removal (every 2–3 years) of this invasive sapling.Synthesis. This experiment showed that native sapling growth was inhibited (i) when growing beneath an invasive canopy and (ii) when competing withA. platanoidesin forest understorey communities. It appears canopy type is more important, because the negative effects from an invasive canopy were strong enough that the co‐occurrence of invasive saplings had no impact on native growth. The capability ofA. platanoidesto inhibit native saplings through understorey competition and overstorey canopy effects, while not affecting conspecifics, may contribute to its success as an invader of North American forests.
100 years of vegetation decline and recovery in Lake Fure, Denmark
Authors: Sand‐Jensen Kaj , Pedersen Niels Lagergaard , Thorsgaard Inge , Moeslund Bjarne , Borum Jens , Brodersen Klaus Peter 
Published: February 2008

Summary

We analysed the development of submerged macrophytes in Lake Fure, Denmark, experiencing a 30‐fold increase of phosphorus input from year 1900 to 1970 and a subsequent decline to twice the 1900 level in 2005. Nutrient enrichment stimulated phytoplankton growth and restricted macrophyte distribution by reducing water transparency from a summer mean of 5–6 m in the early 1900s to a minimum of 1.6 m at the peak of eutrophication, followed by recovery to a recent maximum of 4.1 m.
Macrophyte occurrence and abundance changed in accordance with altered environmental conditions and species’ life‐history traits. Small angiosperms, mosses and characeans disappeared in the 1970s to 1980s, along with all vegetation in deeper waters (5–8 m), and have only partly recovered recently. Tall angiosperms became dominant while small species vanished. All 10 characeans originally present disappeared at the peak of eutrophication, but four reappeared. Mesotrophic macroalgae were replaced by hypertrophic species whose dominance has persisted.
Species richness decreased from 37 to 13 species at the peak of eutrophication, before returning to 25 species during the recent recovery. Species richness increased with transparency because deeper growth generates more niches.
Reduction of species distribution and richness has been reversible following nutrient reduction of the long eutrophied lake, whereas species composition and abundance have not. The historical legacy of community composition is strong, as reflected by closer correlations to time than to measures of nitrogen and phosphorus availability and water transparency.
Synthesis. Although phosphorus input may decline further, reassembly of the original macrophyte community will face difficulties. Oligotrophic freshwater species have become rare throughout Denmark, reducing the probability of recolonization. Species reaching Lake Fure may fail to establish because sediments have become richer in nutrients and organic matter and less consolidated, while shading and competition have increased from emergent reeds, tall submerged angiosperms and fast‐growing macroalgae.
Plant functional composition influences rates of soil carbon and nitrogen accumulation
Authors: Fornara D. A. , Tilman D. 
Published: February 2008

Summary

The mechanisms controlling soil carbon (C) and nitrogen (N) accumulation are crucial for explaining why soils are major terrestrial C sinks. Such mechanisms have been mainly addressed by imposing short‐term, step‐changes in CO2, temperature and N fertilization rates on either monocultures or low‐diversity plant assemblages. No studies have addressed the long‐term effects of plant functional diversity (i.e. plant functional composition) on rates of soil C accumulation in N‐limited grasslands where fixation is the main source of N for plants.
Here we measure net soil C and N accumulation to 1 m soil‐depth during a 12‐year‐long grassland biodiversity experiment established on agriculturally degraded soils at Cedar Creek, Minnesota, USA.
We show that high‐diversity mixtures of perennial grassland plant species stored 500% and 600% more soil C and N than, on average, did monoculture plots of the same species. Moreover, the presence of C4 grasses and legumes increased soil C accumulation by 193% and 522%, respectively. Higher soil C and N accrual resulted both from increased C and N inputs via (i) higher root biomass, and (ii) from greater root biomass accumulation to 60 cm soil depth resulting from the presence of highly complementary functional groups (i.e. C4 grasses and legumes).
Our results suggest that the joint presence of C4 grass and legume species is a key cause of greater soil C and N accumulation in both higher and lower diversity plant assemblages. This is because legumes have unique access to N, and C4 grasses take up and use N efficiently, increasing below‐ground biomass and thus soil C and N inputs.
Synthesis. We demonstrate that plant functional complementarity is a key reason why higher plant diversity leads to greater soil C and N accumulation on agriculturally degraded soils. We suggest the combination of key C4 grass–legume species may greatly increase ecosystem services such as soil C accumulation and biomass (biofuel) production in both high‐ and low‐diversity N‐limited grassland systems.