bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of an induced drought on soil carbon dioxide (CO2) efflux and soil CO2 production in an Eastern Amazonian rainforest, Brazil
Authors: SOTTA ELENEIDE DOFF , VELDKAMP EDZO , SCHWENDENMANN LUITGARD , GUIMARÃES BRENDA ROCHA , PAIXÃO ROSIENE KEILA , RUIVO MARIA de LOURDES P. , LOLA da COSTA ANTONIO CARLOS , MEIR PATRICK 
Published: September 2007

AbstractIn the next few decades, climate of the Amazon basin is expected to change, as a result of deforestation and rising temperatures, which may lead to feedback mechanisms in carbon (C) cycling that are presently unknown. Here, we report how a throughfall exclusion (TFE) experiment affected soil carbon dioxide (CO2) production in a deeply weathered sandy Oxisol of Caxiuanã (Eastern Amazon). Over the course of 2 years, we measured soil CO2 efflux and soil CO2 concentrations, soil temperature and moisture in pits down to 3 m depth. Over a period of 2 years, TFE reduced on average soil CO2 efflux from 4.3±0.1 μmol CO2 m−2 s−1 (control) to 3.2±0.1 μmol CO2 m−2 s−1 (TFE). The contribution of the subsoil (below 0.5 m depth) to the total soil CO2 production was higher in the TFE plot (28%) compared with the control plot (17%), and it did not differ between years. We distinguished three phases of drying after the TFE was started. The first phase was characterized by a translocation of water uptake (and accompanying root activity) to deeper layers and not enough water stress to affect microbial activity and/or total root respiration. During the second phase a reduction in total soil CO2 efflux in the TFE plot was related to a reduction of soil and litter decomposers activity. The third phase of drying, characterized by a continuing decrease in soil CO2 production was dominated by a water stress‐induced decrease in total root respiration. Our results contrast to results of a drought experiment on clay Oxisols, which may be related to differences in soil water retention characteristics and depth of rooting zone. These results show that large differences exist in drought sensitivity among Amazonian forest ecosystems, which primarily seem to be affected by the combined effects of texture (affecting water holding capacity) and depth of rooting zone.
Modelling past and present geographical distribution of the marine gastropodPatella rusticaas a tool for exploring responses to environmental change
Authors: LIMA FERNANDO P. , RIBEIRO PEDRO A. , QUEIROZ NUNO , XAVIER RAQUEL , TARROSO PEDRO , HAWKINS STEPHEN J. , SANTOS ANTÓNIO M. 
Published: September 2007

AbstractA climate envelope approach was used to model the distributions of the intertidal gastropodPatella rustica, to test the robustness of forecast responses to climate change. The model incorporated variables that were likely to determine the abundance and the northern range limit of this species in the NE Atlantic. The model was built using classification and regression tree analysis (CART) trained with historical distribution data from the mid 1950s and a set of corresponding climatic and oceanographic variables. Results indicated air and sea temperature, in particular during the reproductive and settlement periods, as the main determinants of the Atlantic distribution ofP. rustica. The model was subsequently fed with contemporary climatic data and its output was compared with the current distribution and abundance ofP. rustica, assessed during a 2002–2003 survey. The model correctly hindcasted the recent collapse of a distributional gap in northern Portugal, as well as an increase in abundance at locations within its range. The predicted northward expansion of the northern range limit did not occur because the absence of the species was confirmed in a survey encompassing the whole Atlantic French coast up to Brest. Stretches of unsuitable habitat too long to be overcome by dispersal are the likely mechanism controlling the northern limit of the distribution of this intertidal species.
Effects of nutrient loading and extreme rainfall events on coastal tallgrass prairies: invasion intensity, vegetation responses, and carbon and nitrogen distribution
Authors: SIEMANN EVAN , ROGERS WILLIAM E. , GRACE JAMES B. 
Published: September 2007

AbstractSoil fertility and precipitation are major factors regulating transitions from grasslands to forests. Biotic regulation may influence the effects of these abiotic drivers. In this study, we examined the effects of extreme rainfall events, anthropogenic nutrient loading and insect herbivory on the ability of Chinese tallow tree (Sapium sebiferum) to invade coastal prairie to determine how these factors may influence woody invasion of a grassland. We manipulated soil fertility (NPK addition) and simulated variation in frequency of extreme rainfall events in a three growing season, full factorial field experiment. Adding water to or pumping water out of plots simulated increased and decreased rainfall frequencies. We added Sapium seeds and seedlings to each plot and manipulated insect herbivory on transplanted Sapium seedlings with insecticide. We measured soil moisture, Sapium performance, vegetation mass, and carbon and nitrogen in vegetation and soils (0–10 cm deep, 10–20 cm deep). Fertilization increased Sapium invasion intensity by increasing seedling survival, height growth and biomass. Insect damage was low and insect suppression had little effect in all conditions. Recruitment of Sapium from seed was very low and independent of treatments. Vegetation mass was increased by fertilization in both rainfall treatments but not in the ambient moisture treatment. The amount of carbon and nitrogen in plants was increased by fertilization, especially in modified moisture plots. Soil carbon and nitrogen were independent of all treatments. These results suggest that coastal tallgrass prairies are more likely to be impacted by nutrient loading, in terms of invasion severity and nutrient cycling, than by changes in the frequency of extreme rainfall events.
Effect of stand age on greenhouse gas fluxes from a Sitka spruce [Picea sitchensis (Bong.) Carr.] chronosequence on a peaty gley soil
Authors: BALL TOM , SMITH KEITH A. , MONCRIEFF JOHN B. 
Published: September 2007

AbstractThe influence of forest stand age in a Picea sitchensis plantation on (1) soil fluxes of three greenhouse gases (GHGs – CO2, CH4 and N2O) and (2) overall net ecosystem global warming potential (GWP), was investigated in a 2‐year study. The objective was to isolate the effect of forest stand age on soil edaphic characteristics (temperature, water table and volumetric moisture) and the consequent influence of these characteristics on the GHG fluxes. Fluxes were measured in a chronosequence in Harwood, England, with sites comprising 30‐ and 20‐year‐old second rotation forest and a site clearfelled (CF) some 18 months before measurement. Adjoining unforested grassland (UN) acted as a control. Comparisons were made between flux data, soil temperature and moisture data and, at the 30‐year‐old and CF sites, eddy covariance data for net ecosystem carbon (C) exchange (NEE). The main findings were: firstly, integrated CO2 efflux was the dominant influence on the GHG budget, contributing 93–94% of the total GHG flux across the chronosequence compared with 6–7% from CH4 and N2O combined. Secondly, there were clear links between the trends in edaphic factors as the forest matured, or after clearfelling, and the emission of GHGs. In the chronosequence sites, annual fluxes of CO2 were lower at the 20‐year‐old (20y) site than at the 30‐year‐old (30y) and CF sites, with soil temperature the dominant control. CH4 efflux was highest at the CF site, with peak flux 491±54.5 μg m−2 h−1 and maximum annual flux 18.0±1.1 kg CH4 ha−1 yr−1. No consistent uptake of CH4 was noted at any site. A linear relationship was found between log CH4 flux and the closeness of the water table to the soil surface across all sites. N2O efflux was highest in the 30y site, reaching 108±38.3 μg N2O‐N m−2 h−1 (171 μg N2O m−2 h−1) in midsummer and a maximum annual flux of 4.7±1.2 kg N2O ha−1 yr−1 in 2001. Automatic chamber data showed a positive exponential relationship between N2O flux and soil temperature at this site. The relationship between N2O emission and soil volumetric moisture indicated an optimum moisture content for N2O flux of 40–50% by volume. The relationship between C : N ratio data and integrated N2O flux was consistent with a pattern previously noted across temperate and boreal forest soils.
Photosynthesis drives anomalies in net carbon‐exchange of pine forests at different latitudes
Authors: LUYSSAERT S. , JANSSENS I. A. , SULKAVA M. , PAPALE D. , DOLMAN A. J. , REICHSTEIN M. , HOLLMÉN J. , MARTIN J. G. , SUNI T. , VESALA T. , LOUSTAU D. , LAW B. E. , MOORS E. J. 
Published: September 2007

AbstractThe growth rate of atmospheric CO2 exhibits large temporal variation that is largely determined by year‐to‐year fluctuations in land–atmosphere CO2 fluxes. This land–atmosphere CO2‐flux is driven by large‐scale biomass burning and variation in net ecosystem exchange (NEE). Between‐ and within years, NEE varies due to fluctuations in climate. Studies on climatic influences on inter‐ and intra‐annual variability in gross photosynthesis (GPP) and net carbon uptake in terrestrial ecosystems have shown conflicting results. These conflicts are in part related to differences in methodology and in part to the limited duration of some studies. Here, we introduce an observation‐driven methodology that provides insight into the dependence of anomalies in CO2 fluxes on climatic conditions. The methodology was applied on fluxes from a boreal and two temperate pine forests. Annual anomalies in NEE were dominated by anomalies in GPP, which in turn were correlated with incident radiation and vapor pressure deficit (VPD). At all three sites positive anomalies in NEE (a reduced uptake or a stronger source than the daily sites specific long‐term average) were observed on summer days characterized by low incident radiation, low VPD and high precipitation. Negative anomalies in NEE occurred mainly on summer days characterized by blue skies and mild temperatures. Our study clearly highlighted the need to use weather patterns rather than single climatic variables to understand anomalous CO2 fluxes. Temperature generally showed little direct effect on anomalies in NEE but became important when the mean daily air temperature exceeded 23 °C. On such days GPP decreased likely because VPD exceeded 2.0 kPa, inhibiting photosynthetic uptake. However, while GPP decreased, the high temperature stimulated respiration, resulting in positive anomalies in NEE. Climatic extremes in summer were more frequent and severe in the South than in the North, and had larger effects in the South because the criteria to inhibit photosynthesis are more often met.
C4‐derived soil organic carbon decomposes faster than its C3 counterpart in mixed C3/C4 soils
Authors: WYNN JONATHAN G. , BIRD MICHAEL I. 
Published: September 2007

AbstractThe large difference in the degree of discrimination of stable carbon isotopes between C3 and C4 plants is widely exploited in global change and carbon cycle research, often with the assumption that carbon retains the carbon isotopic signature of its photosynthetic pathway during later stages of decomposition in soil and sediments. We applied long‐term incubation experiments and natural 13C‐labelling of C3 and C4‐derived soil organic carbon (SOC) collected from across major environmental gradients in Australia to elucidate a significant difference in the rate of decomposition of C3‐ and C4‐derived SOC. We find that the active pool of SOC (ASOC) derived from C4 plants decomposes at over twice the rate of the total pool of ASOC. As a result, the proportion of C4 photosynthesis represented in the heterotrophic CO2 flux from soil must be over twice the proportional representation of C4‐derived biomass in SOC. This observation has significant implications for much carbon cycle research that exploits the carbon isotopic difference in these two photosynthetic pathways.
Belowground competition and the response of developing forest communities to atmospheric CO2 and O3
Authors: ZAK DONALD R. , HOLMES WILLIAM E. , PREGITZER KURT S. , KING JOHN S. , ELLSWORTH DAVID S. , KUBISKE MARK E. 
Published: September 2007

AbstractAs human activity continues to increase CO2 and O3, broad expanses of north temperate forests will be simultaneously exposed to elevated concentrations of these trace gases. Although both CO2 and O3 are potent modifiers of plant growth, we do not understand the extent to which they alter competition for limiting soil nutrients, like nitrogen (N). We quantified the acquisition of soil N in two 8‐year‐old communities composed of trembling aspen genotypes (n= 5) and trembling aspen–paper birch which were exposed to factorial combinations of CO2 (ambient and 560 μL L−1) and O3 (ambient = 30–40 vs. 50–60 nL L−1). Tracer amount of 15NH4+ were applied to soil to determine how these trace gases altered the competitive ability of genotypes and species to acquire soil N. One year after isotope addition, we assessed N acquisition by measuring the amount of 15N tracer contained in the plant canopy (i.e. recent N acquisition), as well as the total amount of canopy N (i.e. cumulative N acquisition). Exposure to elevated CO2 differentially altered recent and cumulative N acquisition among aspen genotypes, changing the rank order in which they obtained soil N. Elevated O3 also altered the rank order in which aspen genotypes obtained soil N by eliciting increases, decreases and no response among genotypes. If aspen genotypes respond similarly under field conditions, then rising concentrations of CO2 and O3 could alter the structure of aspen populations. In the aspen–birch community, elevated CO2 increased recent N (i.e. 15N) acquisition in birch (68%) to a greater extent than aspen (19%), suggesting that, over the course of this experiment, birch had gained a competitive advantage over aspen. The response of genotypes and species to rising CO2 and O3 concentrations, and how these responses are modified by competitive interactions, has the potential to change the future composition and productivity of northern temperate forests.
Exploring research supervision through Peshkin’s I’s: the yellow brick road
Authors: Bradbury‐Jones Caroline 
Published: September 2007

Abstract Title. Exploring research supervision through Peshkin’s I’s: the yellow brick road Aim.  This paper is a report of a systematic approach used to explore subjectivity as a research student and demonstrates how the process enhanced the quality of the research experience.Background.  High non‐completion rates of research students are of global concern and means of enhancing the quality of the doctoral experience are needed. Among the literature on doctoral education, very little is authored by students. This paper is influenced by the work of Peshkin from the discipline of education. Peshkin articulated the need for researchers to systematically identify their subjectivity by searching for their subjective I’s. I share my experience of adopting this approach as a research student by using reflexive journal entries made during 2005–2007 as data.Findings.  I use the analogy of the ‘Yellow Brick Road’ from The Wizard of Oz to represent my experience of being a doctoral student and draw comparisons between my subjectivity and the characters in the story. I demonstrate how a systematic approach to exploring my subjectivity revealed aspects of my being as a research student that had potential for influence throughout the entirety of my experience. I argue that cognizance of my subjective I’s improved the quality of my research endeavour.Conclusion.  The approach is offered for consideration by other research students as a means of exploring subjectivity. I argue that the resultant self‐awareness can enhance the quality of the doctoral experience. The flexibility of the approach means it has transferability across a number of disciplines and cultural contexts.
Women’s experience of internal radiation treatment for uterine cervical cancer
Authors: So Winnie Kwok‐wei , Chui Ying‐yu 
Published: September 2007

Abstract Title. Women’s experience of internal radiation treatment for uterine cervical cancer Aim.  This paper is a report of a study to explore the experiences of women undergoing internal radiation for cervical cancer.Background.  Cervical cancer continues to be one of the most common cancers and one of the leading causes of cancer deaths globally. Women’s experiences of undergoing internal radiation for cervical cancer remain relatively unexplored, in particular in Hong Kong. Better understanding of the experiences of this specific group could inform the provision of supportive care services and provide useful information to be included in education programmes for them.Method.  A phenomenological approach was adopted and unstructured telephone interviews were carried out with eight participants between July and October 2004. The interviews were audio‐taped and analysed using the procedures described by Giorgi, 1985.Findings.  Three themes were identified from the data: (1) isolation versus social intercourse, (2) unbearable symptom distress versus endurance and coping and (3) growth from the experience. The most distressing aspects of undergoing internal cervical irradiation reported by the patients were the experience of isolation and various physical and psychological symptoms. Specific provisions in the physical environment, psychological support provided by healthcare professionals, family and fellow patients and a positive attitude helped them to cope. They also felt that they became stronger through their hardship and suffering.Conclusion.  The findings highlight the importance of adequate preparation of patients, carers and friends before the procedure, more sensitive support during the procedure and debriefing afterwards. There might also be benefits in delivering therapy to two women in adjacent beds to enable them to support each other.
Barriers to evidence‐based nursing: a focus group study
Authors: Hannes Karin , Vandersmissen Jo , De Blaeser Liesbeth , Peeters Gert , Goedhuys Jo , Aertgeerts Bert 
Published: September 2007

Abstract Title. Barriers to evidence‐based nursing: a focus group study Aim.  This paper reports a study to explore the barriers to evidence‐based nursing among Flemish (Belgian) nurses.Background.  Barriers obstructing the call for an increase in evidence‐based nursing have been explored in many countries, mostly through quantitative study designs. Authors report on lack of time, resources, evidence, authority, support, motivation and resistance to change. Relationships between barriers are seldom presented.Methods.  We used a grounded theory approach, and five focus groups were organized between September 2004 and April 2005 in Belgium. We used purposeful sampling to recruit 53 nurses working in different settings. A problem tree was developed to establish links between codes that emerged from the data.Findings.  The majority of the barriers were consistent with previous findings. Flemish (Belgian) nurses added a potential lack of responsibility in the uptake of evidence‐based nursing, their ‘guest’ position in a patient’s environment leading to a culture of adaptation, and a future ‘two tier’ nursing practice, which refers to the different education levels of nurses. The problem tree developed serves as (1) a basic model for other researchers who want to explore barriers within their own healthcare system and (2) a useful tool for orienting change management processes.Conclusion.  Despite the fact that the problem tree presented is context‐specific for Flanders (Belgium), it gives an opportunity to develop clear objectives and targeted strategies for tackling obstacles to evidence‐based nursing.
Encounters in Swedish nursing homes: a hermeneutic study of residents’ experiences
Authors: Westin Lars , Danielson Ella 
Published: September 2007

AbstractTitle. Encounters in Swedish nursing homes: a hermeneutic study of residents’ experiencesAim. This paper is a report of a study to illuminate and interpret the meaning of residents’ experiences of encounters with nurses in nursing homes.Background. A large number of older people suffer from illness and become dependent on other people in their daily living. These people are often in need of care in nursing homes. It is assumed that encounters between nurses and residents are of importance in how residents experience care in nursing homes.Method. Twelve residents from three nursing homes in Sweden were interviewed in 2004–2005 about their experiences in encounters with nurses. The interviews were tape‐recorded and transcribed verbatim. A hermeneutic method was used to describe and interpret the meaning of residents’ experiences.Findings. Three themes emerged: ‘being somebody’, ‘being nobody’ and ‘being in a community’. The encounters had both positive and negative influences on residents, expressed as being somebody and belonging somewhere or being nobody and not being seen as a person or simply being left out of things. Encounters between residents and nurses have a mutual dependency where residents certainly have some influence on the relationship. The nurses have both an influence on the relationship and a professional responsibility for the outcome of encounters with residents.Conclusion. The insights gained from the study can guide nurses in their encounters with residents in nursing homes so that they feel respected as unique human beings and part of a community.
Best practice interventions to improve the management of older people in acute care settings: a literature review
Authors: Hickman Louise , Newton Phillip , Halcomb Elizabeth J. , Chang Esther , Davidson Patricia 
Published: September 2007

AbstractTitle. Best practice interventions to improve the management of older people in acute care settings: a literature reviewAim. This paper is a report of a literature review of experimental evidence describing interventions to manage the older adult in the acute care hospital setting.Background. Older people are increasingly being cared for in a system largely geared towards acute care. This approach is often inadequate to meet the needs of older patients with chronic and complex conditions. In response to these challenges, evidence‐based interventions are required to improve health outcomes.Method. The MEDLINE and CINAHL databases and the Internet were searched using the keywords elderly, older, geriatric and aged care. Studies published between 1985 and 2006 were included if they reported, in English, a controlled trial of an intervention designed to improve the management of older adults in the acute care setting. The findings were synthesized using the method of a modified integrative literature review.Findings. Only 26 controlled trials met the inclusion criteria. The following elements of interventions appear critical in providing optimal health outcomes for older people admitted to acute care: (1) a team approach to care delivery either directly in a designated unit for older patients or indirectly using gerontological expertise in a consultancy model; (2) targeted assessment techniques to prevent complications; (3) an increased emphasis on discharge planning and (4) enhanced communication between care providers across the care continuum.Conclusion. A multidisciplinary team approach, using gerontological expertise, in acute care settings is recommended to improve the care of older patients. Care delivery should occur in a specially designed unit, with communication strategies that emphasize discharge planning.