bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geographic patterns of functional categories of HLA‐DRB1 alleles: a new approach to analyse associations between HLA‐DRB1 and disease
Authors: Gibert M. , Sanchez‐Mazas A. 
Published: October 2003

SummaryBecause specific amino acids found within the peptide‐binding cleft of human leukocyte antigen (HLA) molecules have been implicated in HLA/disease associations, an approach which consists in grouping the alleles according to their functional properties at the protein level may enable us to better understand HLA associations than the conventional allelic classification. In this study, we applied this methodology to investigate the associations between HLA‐DRB1 and rheumatoid arthritis. The alleles were first classified into seven functional categories [restrictive supertype patterns (RSPs)], among which three were known to be significantly associated with susceptibility (one category) or resistance (two categories) to rheumatoid arthritis. The frequencies of these categories were then estimated in 104 population samples previously tested for HLA‐DRB1, and their variability was analysed spatially on a worldwide scale by applying an original methodology for detecting discontinuities in geographically patterned data. RSP frequencies were also compared to known values of rheumatoid arthritis prevalence in some populations. The results indicated that the three RSP frequency distributions were geographically structured, and that these patterns could generally be explained by the history of human migrations. However, the peculiar pattern observed for RSP ‘A’ (conferring susceptibility to rheumatoid arthritis) indicated a possible association with some latitude‐dependent disease. Furthermore, the very high correlation coefficient found between RSP ‘A’ frequencies and rheumatoid arthritis prevalence confirmed the significant disease association of this functional category. In contrast, the putative protective effect of the other RSPs (‘De’ and ‘Q’) was not detectable at the worldwide level, but may be significant in specific geographic areas. This study shows that population genetic diversity analyses based on a functional grouping of HLA alleles provide an efficient way to explore the mutual influence of HLA genetic variation and disease.
Non‐equilibrium succession dynamics indicate continued northern migration of lodgepole pine
Authors: Johnstone Jill F. , Chapin F. Stuart 
Published: October 2003

AbstractBecause species affect ecosystem functioning, understanding migration processes is a key component of predicting future ecosystem responses to climate change. This study provides evidence of range expansion under current climatic conditions of an indigenous species with strong ecosystem effects. Surveys of stands along the northern distribution limit of lodgepole pine (Pinus contorta var. latifolia) in central Yukon Territory, Canada showed consistent increases in pine dominance following fire. These patterns differed strongly from those observed at sites where pine has been present for several thousand years. Differences in species thinning rates are unlikely to account for the observed increases in pine dominance. Rates of pine regeneration at its range limits were equivalent to those of spruce, indicating a capacity for rapid local population expansion. The study also found no evidence of strong climatic limitation of pine population growth at the northern distribution limit. We interpret these data as evidence of current pine expansion at its range limits and conclude that the northern distribution of lodgepole pine is not in equilibrium with current climate. This study has implications for our ability to predict vegetation response to climate change when populations may lag in their response to climate.
Effects of free‐air CO2enrichment (FACE) on CH4emission from a rice paddy field
Authors: Inubushi Kazuyuki , Cheng Weiguo , Aonuma Shinichi , Hoque M.M. , Kobayashi Kazuhiko , Miura Shu , Kim Han Yong , Okada Masumi 
Published: October 2003

AbstractMethane (CH4) is a particularly potent greenhouse gas with a radiative forcing 23 times that of CO2on a per mass basis. Flooded rice paddies are a major source of CH4emissions to the Earth's atmosphere. A free‐air CO2enrichment (FACE) experiment was conducted to evaluate changes in crop productivity and the crop ecosystem under enriched CO2conditions during three rice growth seasons from 1998 to 2000 in a rice paddy at Shizukuishi, Iwate, Japan. To understand the influence of elevated atmospheric CO2concentrations on CH4emission, we measured methane flux from FACE rice fields and rice fields with ambient levels of CO2during the 1999 and 2000 growing seasons. Methane production and oxidation potentials of soil samples collected when the rice was at the tillering and flowering stages in 2000 were measured in the laboratory by the anaerobic incubation and alternative propylene substrates methods, respectively. The average tiller number and root dry biomass were clearly larger in the plots with elevated CO2during all rice growth stages. No difference in methane oxidation potential between FACE and ambient treatments was found, but the methane production potential of soils during the flowering stage was significantly greater under FACE than under ambient conditions. When free‐air CO2was enriched to 550 ppmv, the CH4emissions from the rice paddy field increased significantly, by 38% in 1999 and 51% in 2000. The increased CH4emissions were attributed to accelerated CH4production potential as a result of more root exudates and root autolysis products and to increased plant‐mediated CH4emissions because of the larger rice tiller numbers under FACE conditions.
Solar UV‐B decreases decomposition in herbaceous plant litter in Tierra del Fuego, Argentina: potential role of an altered decomposer community
Authors: Pancotto Verónica A. , Sala Osvaldo E. , Cabello Marta , López Nancy I. , Matthew Robson T. , Ballaré Carlos L. , Caldwell Martyn M. , Scopel Ana L. 
Published: October 2003

AbstractTierra del Fuego, Argentina (55°S), receives increased solar ultraviolet‐B radiation (UV‐B) as a result of Antarctic stratospheric ozone depletion. We conducted a field study to examine direct and indirect effects of solar UV‐B radiation on decomposition ofGunnera magellanica, a native perennial herb, and on the native community of decomposer organisms. In general, indirect effects of UV‐B mostly occur due to changes in the chemical composition of litter, whereas direct effects during decomposition result from changes in decomposer organisms and/or differences in the photochemical breakdown of litter. We designed a full‐factorial experiment using senescent leaves that had received either near‐ambient or attenuated UV‐B during growth. The leaves were distributed in litterbags and allowed to decompose under near‐ambient or reduced solar UV‐B during the growing season. We evaluated initial litter quality, mass loss, and nutrient release of decomposing litter, and microbial colonization of both initial litter and decomposed litter. We found that litter that decomposed under near‐ambient UV‐B had significantly less mass loss than litter that decomposed under reduced UV‐B. The UV‐B conditions received by plants during growth, which did not affect mass loss and nutrient composition of litter, affected fungal species composition but in different ways throughout the decomposition period. Before the decomposition trial,Beauveria bassianaandPenicillium frequentanswere higher under reduced UV‐B, whereasCladosporium herbarumand pigmented bacteria were more common under the near‐ambient compared to the reduced UV‐B treatment. After the decomposition period, leaves that had grown under reduced UV‐B showed higher frequency ofPenicillium thomiiand lower frequency ofTrichoderma polysporumthan leaves that had grown under near‐ambient conditions. The UV‐B condition received during decomposition also affected fungal colonization, withPenicillium chrysogenumbeing more frequent in leaves that had decomposed under reduced UV‐B, while the other species were not affected. Our results demonstrate that, in this ecosystem, the effects of UV‐B radiation on decomposition apparently occurred mostly through changes in the fungal community, while changes in photochemical breakdown appeared to be less important.
Topographic and climatic controls on soil respiration in six temperate mixed‐hardwood forest slopes, Korea
Authors: Kang Sinkyu , Doh Sueyoung , Lee Dongsun. , Lee Dowon. , Jin Virginia L. , Kimball John S. 
Published: October 2003

AbstractTo better understand the effects of local topography and climate on soil respiration, we conducted field measurements and soil incubation experiments to investigate various factors influencing spatial and temporal variations in soil respiration for six mixed‐hardwood forest slopes in the midst of the Korean Peninsula. Soil respiration and soil water content (SWC) were significantly greater (P=0.09 and 0.003, respectively) on north‐facing slopes compared to south‐facing slopes, while soil temperature was not significantly different between slopes (P>0.5). At all sites, soil temperature was the primary factor driving temporal variations in soil respiration (r2=0.84–0.96) followed by SWC, which accounted for 30% of soil respiration spatial and temporal variability. Results from both field measurements and incubation experiments indicate that variations in soil respiration due to aspect can be explained by a convex‐shaped function relating SWC to normalized soil respiration rates. Annual soil respiration estimates (1070–1246 g C m−2 yr−1) were not closely related to mean annual air temperatures among sites from different climate regimes. When soils from each site were incubated at similar temperatures in a laboratory, respiration rates for mineral soils from wetter and cooler sites were significantly higher than those for the drier and warmer sites (n=4, P<0.01). Our results indicate that the application of standard temperature‐based Q10 models to estimate soil respiration rates for larger geographic areas covering different aspects or climatic regimes are not adequate unless other factors, such as SWC and total soil nitrogen, are considered in addition to soil temperature.
Historical shrub–grass transitions in the northern Chihuahuan Desert: modeling the effects of shifting rainfall seasonality and event size over a landscape gradient
Authors: Gao Qiong , Reynolds James F. 
Published: October 2003

AbstractWe use a spatially explicit landscape model to investigate the potential role of rainfall on shrub–grass transitions in the Jornada Basin of southern New Mexico during the past century. In long‐term simulations (1915–1998) along a 2700 m transect running from a dry lake bed to the foothills of a small mountain, we test two hypotheses: (i) that wetter winters and drier summers may have facilitated shrub encroachment in grasslands, and (ii) that increases in large precipitation events may have increased soil water recharge at deeper layers, thus favoring shrub establishment and growth. Our model simulations generally support the hypothesis that wetter winters and drier summers may have played a key role, but we are unable to reproduce the major shifts from grass‐ to shrub‐domination that occurred in this landscape during the early part of the 1900s; furthermore, the positive shrub response to wetter winters and drier summers was only realized subsequent to the drought of 1951–1956, which was a relatively short ‘window of opportunity’ for increased shrub establishment and growth. Our simulations also generally support the hypothesis that an increase in the number of large precipitation events may also have favored shrub establishment and growth, although these results are equivocal, depending upon what constitutes a ‘large’ event and the timing of such events. We found complex interactions among (i) the amount/seasonality of rainfall, (ii) its redistribution in the landscape via run‐on and runoff, (iii) the depth of the soil water recharge, and (iv) subsequent water availability for the growth and reproduction of shrubs vs. herbaceous plants at various landscape positions. Our results suggest that only a mechanistic understanding of these interactions, plus the role of domestic cattle grazing, will enable us to elucidate fully the relative importance of biotic vs. abiotic factors in vegetation dynamics in this semiarid landscape.
Effects of climatic change on the phenology of butterflies in the northwest Mediterranean Basin
Authors: Stefanescu Constantí , Peñuelas Josep , Filella Iolanda 
Published: October 2003

AbstractPhenological changes in response to climatic warming have been detected across a wide range of organisms. Butterflies stand out as one of the most popular groups of indicators of climatic change, given that, firstly, they are poikilothermic and, secondly, have been the subject of thorough monitoring programmes in several countries for a number of decades. Here we provide for the first time strong evidence of phenological change as a consequence of recent climatic warming in butterflies at a Spanish site in the northwest Mediterranean Basin. By means of the widely used Butterfly Monitoring Scheme methodology, three different phenological parameters were analysed for the most common species to test for trends over time and relationships with temperature and precipitation. Between 1988 and 2002, there was a tendency for earlier first appearance dates in all 17 butterfly species tested, and significant advances in mean flight dates in 8 out of 19 species. On the other hand, the shape of the curve of adult emergence did not show any regular pattern. These changes paralleled an increase of 1–1.5°C in mean February, March and June temperatures. Likewise, a correlation analysis indicated the strong negative effect of spring temperature on phenological parameters (i.e. higher temperatures tended to produce phenological advances), and the opposite effect of precipitation in certain months. In addition, there was some evidence to indicate that phenological responses may differ between taxonomic lineages or species with similar diets. We discuss the consequences that these changes may have on species' population abundances, especially given the expected increase in aridity in the Mediterranean Basin caused by current climatic warming. We predict that varying degrees of phenological flexibility may account for differences in species' responses and, for multivoltine species, predict strong selection favouring local seasonal adaptations such as diapause phenomena or migratory behaviour.
A meta‐analysis of the effects of various interventions in preventing endotracheal suction‐induced hypoxemia
Authors: Oh HyunSoo , Seo WhaSook 
Published: October 2003

Summary• The purpose of this study was to clarify the effects of interventions that were applied to prevent endotracheal suction‐induced hypoxia by meta‐analysis.• To obtain a sample for this meta‐analysis, a computerized search was performed through MEDLINE in addition to tracking down additional references cited in bibliographies of past reports. Finally thirty research reports were examined.• In terms of the application time of oxygenation, insufflation and preoxygenation were the most prevalently used in the studies.• Regarding the methods of oxygenation, the most prevalent technique for oxygenation was hyperoxygenation in combination with hyperinflation.• Hyperoxygenation and hyperinflation were most frequently induced by FiO2 of 1 and a 150% tidal volume of three to six breaths, respectively.• Suctioning was commonly sustained for <15 seconds using pressures of −80 to −120 mmHg and with size 14 French catheters.• Insufflation was less effective than the other methods examined in the present study.• From this study, it can be concluded that the interventions that were applied to prevent endotracheal suction‐induced hypoxia, regardless of their application times or methods, reduced suction‐induced hypoxia significantly.
Problems identified in gaining non‐expert consensus for a hypothetical Wound Assessment Form
Authors: Maylor Miles E. 
Published: October 2003

Summary• A post‐hoc analysis was carried out of a session on a wound management diploma level module that was intended to promote understanding of the complexity of wound assessment.• Postregistration student nurses (n = 16) from both hospital and community settings participated in brainstorming of categories (i.e. verbatim expression) they thought should be included in a hypothetical Wound Assessment Form (WAF).• Ranking of suggested categories indicated in terms of ‘votes’ that the most important was ‘date’, and the least was ‘factors affecting healing’. Some categories were rejected (e.g. exudate).• Category definitions and rationale were checked after 3 weeks, and compared with those of lecturers in adult nursing (n = 16) to test whether similar themes emerged amongst other non‐experts.• Postregistration nurses and lecturers gave similar definitions and rationale for categories.• A limitation of the study was that it was opportunistic and methodology for researching consensus issues had not been investigated. Views represent nurses in a wide spread of disciplines and have to date only been compared with expert consensus derived from published literature.• Themes to emerge were: the importance of WAFs to record‐keeping, different understanding of terminology and the monitoring of progress and use of intuition.• It was concluded that the purpose of WAFs needs clarification and research should investigate how change in wounds could take account of differences of personal perception. A new method of charting progress or deterioration is being developed.
Home care with regard to definition, care recipients, content and outcome: systematic literature review
Authors: Thomé Bibbi , Dykes Anna‐Karin , Hallberg Ingalill Rahm 
Published: October 2003

Summary• In spite of the fact that home care has grown considerably during the last few years and will continue to grow even more in the future, home care as a phenomenon and a concept is not clearly defined.• The aim of this study was to review the empirical literature for the description of home care as a phenomenon and as a concept, especially with regard to who the care recipients are, what actions and assessments are performed and what effects are achieved for the care recipient in terms of functional health status and quality of life (QoL).• Twenty‐six relevant studies meeting the inclusion criteria and requirements for methodological quality were identified.• The phenomenon of home care is described through content, outcome and objectives. The content of home care involved a range of activities from actions preventing decreased functional abilities in old people to palliative care in advanced diseases.• The outcome had two different underlying foci: (1) for the benefit of the patient based on the assumption that being cared at home increases their QoL, (2) in the interests of the society, to minimize hospital care by moving activities to the home of the patient.• The objectives were found to be aiming at improving the QoL and/or maintaining independence, by means of actions and assessments, based on the patient's needs, undertaken to preserve and increase functional ability and make it possible for the person to remain at home.• In conclusion, home care as a phenomenon was the care provided by professionals to people in their own homes with the ultimate goal of not only contributing to their life quality and functional health status, but also to replace hospital care with care in the home for societal reasons; home care covered a wide range of activities, from preventive visits to end‐of‐life care.
Risk of haemorrhagic stroke in patients with oral anticoagulation compared with the general population
Authors: Själander A. , Engström G. , Berntorp E. , Svensson P. 
Published: October 2003

Abstract.  Själander A, Engström G, Berntorp E, Svensson P (Malmö University Hospital, University of Lund, Sweden). Risk of haemorrhagic stroke in patients with oral anticoagulation compared with the general population. J Intern Med 2003; 254: 434–438.Objectives.  To compare the incidence of haemorrhagic stroke (HS), and the risk of fatal outcome after HS in patients with oral anticoagulation (OA) treatment and in the general population.Design.  Five‐year cohort study.Setting.  The Anticoagulation Clinic, Malmö University Hospital, Lund, Sweden.Subjects.  A total of 4434 patients treated with OA (6693 treatment years) from 1 Oct 1993 to 30 Sept 1998. The population‐based Stroke Register of Malmö, Lund, Sweden (STROMA).Results.  Forty‐eight patients had HS according to ICD 9 code 430 and 431. HS occurred at a higher age in women compared with men (mean age 79.5 years vs. 74.7 years, P = 0.009). The age‐adjusted relative risk of HS during OA treatment was 10.9 (CI 6.7–17.6) for men and 9.3 (CI 5.7–15.0) for women, as compared with the untreated general population. Number needed to harm (NNH) (person‐years) was 103 for men and 188 for women. Adjusted for age and sex, OA treatment was significantly associated with fatal outcome in patients with HS (OR = 2.6, CI 1.4–4.8).Conclusions.  Patients with OA treatment had approximately 10 times higher risk of HS as compared with the general population, and the risk increased markedly with age. OA treatment is associated with an increased case fatality in patients with HS.
Endocrine effects of nasal continuous positive airway pressure in male patients with obstructive sleep apnoea
Authors: Meston N. , Davies R. J. O. , Mullins R. , Jenkinson C. , Wass J. A. H. , Stradling J. R. 
Published: October 2003

Abstract. Meston N, Davies RJO, Mullins R, Jenkinson C, Wass JAH, Stradling JR (University of Oxford, John Radcliffe Hospital; Oxford Centre for Respiratory Medicine and University of Oxford, Churchill Hospital; Health Services Research Unit; Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Infirmary; Oxford, UK). Endocrine effects of nasal continuous positive airway pressure in male patients with obstructive sleep apnoea. J Intern Med 2003; 254: 447–454.Objective. Obstructive sleep apnoea (OSA) is a relatively common condition producing disabling somnolence and profound physiological responses to hypoxaemic episodes during sleep, including significant oscillations in blood pressure. This study aimed to provide controlled data on the interaction between OSA and endocrine axes to establish whether overrepresentation of pathology such as hypertension and hypogonadism in OSA subjects might have an endocrine basis.Design, setting and subjects. Parallel randomized sham placebo controlled 1‐month trial of nasal continuous positive airway pressure (nCPAP) in 101 male subjects with OSA presenting to a respiratory sleep clinic.Methods. Analysis of gonadotrophins, testosterone, sex hormone binding protein (SHBG), prolactin, cortisol, thyroid stimulating hormone (TSH), free thyroxine (free T4), insulin‐like growth factor‐1 (IGF‐1), renin and aldosterone were performed at baseline and after 1 month's active or placebo nCPAP intervention. Quality of life questionnaire scoring was also recorded over the same time period.Results. Testosterone and SHBG showed significant negative correlations with baseline OSA severity. Active treatment of OSA produced SHBG elevation and TSH reduction (P ≤ 0.03). Both groups showed an increase in aldosterone (P < 0.001) and IGF‐1 (P ≤ 0.03), associated with a large improvement in subjective quality of life scoring.Conclusions. These findings demonstrate significant changes in endocrine axes not previously reported in a placebo‐controlled trial. OSA is a recognized reversible cause of testosterone reduction; SHBG suppression correlating to baseline OSA severity supports a diagnosis of secondary hypogonadism. Significant rises in aldosterone and IGF‐1 on treatment coincide with increased physical activity and an improved quality of life score.