bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dependence of carbon sequestration on the differential responses of ecosystem photosynthesis and respiration to rain pulses in a semiarid steppe
Authors: CHEN SHIPING , LIN GUANGHUI , HUANG JIANHUI , JENERETTE G. DARREL 
Published: February 2009

AbstractPrecipitation pulses play an important role in regulating ecosystem carbon exchange and balance of semiarid steppe ecosystems. It has been predicted that the frequency of extreme rain events will increase in the future, especially in the arid and semiarid regions. We hypothesize that large rain pulses favor carbon sequestration, while small ones cause more carbon release in the semiarid steppes. To understand the potential response in carbon sequestration capacity of semiarid steppes to the changes in rain pulse size, we conducted a manipulative experiment with five simulated rain pulse sizes (0, 5, 10, 25, and 75 mm) in Inner Mongolia steppe. Our results showed that both gross ecosystem productivity (GEP) and ecosystem respiration (Re) responded rapidly (within 24 h) to rain pulses and the initial response time was independent of pulse size. However, the time of peak GEP was 1–3 days later than that of Re, which depended on pulse size. Larger pulses caused greater magnitude and longer duration of variations in GEP and Re. Differences in the response time of microbes and plants to wetting events constrained the response pattern of heterotrophic (Rh) and autotrophic (Ra) components of Re following a rain event. Rh contributed more to the increase of Re in the early stage of rain pulse response, while Ra played an more important role later, and determined the duration of pulse response, especially for large rain events of >10 mm. The distinct responses of ecosystem photosynthesis and respiration to increasing pulse sizes led to a threshold in rain pulse size between 10 and 25 mm, above which post wetting responses favored carbon sequestration. The disproportionate increase of the primary productivity of higher plants, compared with those in the activities of microbial decomposers to larger pulse events suggests that the carbon sequestration capacity of Inner Mongolia steppes will be sensitive to changes in precipitation size distribution rather than just precipitation amount.
Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments
Authors: KOKFELT U. , ROSÉN P. , SCHONING K. , CHRISTENSEN T. R. , FÖRSTER J. , KARLSSON J. , REUSS N. , RUNDGREN M. , CALLAGHAN T. V. , JONASSON C. , HAMMARLUND D. 
Published: February 2009

AbstractRecent accelerated decay of discontinuous permafrost at the Stordalen Mire in northern Sweden has been attributed to increased temperature and snow depth, and has caused expansion of wet minerotrophic areas leading to significant changes in carbon cycling in the mire. In order to track these changes through time and evaluate potential forcing mechanisms, this paper analyses a peat succession and a lake sediment sequence from within the mire, providing a record for the last 100 years, and compares these with monitored climate and active layer thickness data. The peat core was analysed for testate amoebae to reconstruct changes in peatland surface moisture conditions and water table fluctuations. The lake sediment core was analysed by near infrared spectroscopy to infer changes in the total organic carbon (TOC) concentration of the lake‐water, and changes inδ13C and C, N andδ15N to track changes in the dissolved inorganic carbon (DIC) pool and the influence of diagenetic effects on sediment organic matter, respectively. Results showed that major shifts towards increased peat surface moisture and TOC concentration of the lake‐water occurred around 1980, one to two decades earlier than a temperature driven increase in active layer thickness. Comparison with monitored temperature and precipitation from a nearby climate station indicates that this change in peat surface moisture is related to June–September (JJAS) precipitation and that the increase in lake‐water TOC concentration reflects an increase in total annual precipitation. A significant depletion in13C of sediment organic matter in the early 1980s probably reflects the effect of a single or a few consecutive years with anomalously high summer precipitation, resulting in elevated DIC content of the lake water, predominantly originating from increased export and subsequent respiration of organic carbon from the mire. Based on these results, it was not possible to link proxy data obtained on peat and lake‐sediment records directly to permafrost decay. Instead our data indicate that increased precipitation and anomalously high rainfall during summers had a significant impact on the mire and the adjacent lake ecosystem. We therefore propose that effects of increased precipitation should be considered when evaluating potential forcing mechanisms of recent changes in carbon cycling in the subarctic.
Climate change and bet‐hedging: interactions between increased soil temperatures and seed bank persistence
Authors: OOI MARK K. J. , AULD TONY D. , DENHAM ANDREW J. 
Published: February 2009

AbstractIn order to predict the long‐term consequences of climate change, it is necessary to link future environmental changes to mechanisms that control plant population processes. This information can then be incorporated into strategies to more accurately model climate change impacts on species or to estimate future extinction risks. We examined the impact of increased temperatures on the longevity and dynamics of the persistent soil seed banks of eight ephemeral species from arid Australia. We found that the predicted global temperature increases under climate change will be reflected in increased soil temperatures, and that seeds in the soil seed bank will be exposed to long durations of high temperatures over the summer months. Three of the eight species studied had significantly greater levels of germination after exposure to predicted increased soil temperatures. Another species displayed a dramatic decrease in seed viability after such exposure. The capacity of such species to use the seed bank to bet hedge against rainfall events that cause germination but are insufficient to allow plant maturation, is compromised by increased germinability and subsequent loss or reduction of seed bank persistence. These predicted changes in the dynamics of soil seed banks increase the risk of local extinctions of these species, while the composition of the community may be altered by changes in species abundance. Our results show that the risk spreading mechanism provided by persistent seed banks could be compromised by the mechanistic impact of forecast temperature increases in arid habitats, and highlight the need to understand mechanisms that control population dynamics when attempting to address likely future impacts of climate change on biodiversity.
Climate‐related, decadal‐scale assemblage changes of seagrass‐associated fishes in the northern Gulf of Mexico
Authors: FODRIE F. JOEL , HECK KENNETH L. , POWERS SEAN P. , GRAHAM WILLIAM M. , ROBINSON KELLY L. 
Published: February 2009

AbstractGlobal temperatures are rising, and are expected to produce a poleward shift in the distribution of many organisms. We quantified changes in fish assemblages within seagrass meadows of the northern Gulf of Mexico (GOM) between the 1970s and 2006–2007, and observed changes consistent with this forecast. During 2006–2007 we sampled seagrass meadows using the same gears and methods previously employed by R. J. Livingston in coastal waters of northwest Florida throughout the 1970s. Comparisons between datasets revealed numerous additions to the fish fauna during 2006–2007 that were completely absent in the 1970s, including: Lutjanus synagris (lane snapper), Epinephelus morio (red grouper), Chaetodon ocellatus (spotfin butterflyfish), Mycteroperca sp (grouper, non gag), Centropristis philadelphica (rock sea bass), Fistularia tabacaria (bluespotted cornetfish), Ocyurus chrysurus (yellowtail snapper), Thalassoma bifasciatum (bluehead wrasse), Abudefduf saxatilis (sergeant major), Acanthuridae spp. (surgeonfishes) and Sparisoma viride (stoplight parrotfish). Several other species showed large increases in abundance during the interval between 1979 and 2006, including Mycteroperca microlepis (gag grouper, up ∼200 ×), Lutjanus griseus (gray snapper, up ∼105 ×), and Nicholsina usta (emerald parrotfish, up ∼22 ×). All of these are tropical or subtropical species that now make up a greater percentage of seagrass‐associated fish assemblages in the northern GOM than in the past. Additionally, we observed regional increases in air and sea surface temperatures (> 3 °C) during the ∼30 years that separate Livingston's samples and ours that correlate with northern shifts in the distribution of warm‐water fishes. Documenting these range shifts is a critical first step in investigating the consequences of global warming for endemic marine communities and fishery production in the northern GOM.
The historical and situated nature design experiments – Implications for data analysis
Authors: Krange I. , Ludvigsen Sten 
Published: February 2009

AbstractThis article is a methodological contribution to the use of design experiments in educational research. We will discuss the implications of a historical and situated interpretation to design experiments, the consequences this has for the analysis of the collected data and empirically based suggestions to improve the designs of the computer‐based learning resources. This interpretation differs from that of the majority of other researchers who consider design experiments as fixed interventions. Our interpretation allows for an understanding of students' learning trajectories as part of the school's overall activities, which in turn has implications for suggestions regarding the improvement of computer‐based learning resources. We develop argument in three different ways. First, we discuss our interpretation of design experiments and compare it with the dominant debate about design experiments as a methodological approach. Second, we discuss the implications this position has for interaction analysis methods. Finally, we empirically demonstrate this methodological implication by illustrating how vital it might be to consider data collected as part of design experiments as an element of a larger, established institutional setting characterized by inherent socio‐cultural features. A conclusion that may be drawn from our situated interpretation of this design experiment is that, to improve students' knowledge constructions, it is not enough – nor is it in principle possible – to perfect the design of the technology. We also need to improve institutional aspects on how schools support students' knowledge constructions when using these technological tools, where the teacher's role in this work is invaluable. A historical and situated interpretation of design experiments provides insight into how these improvements may be made.
Advances in insectivore and rodent systematics due to geometric morphometrics
Authors: BARČIOVÁ LENKA 
Published: February 2009

ABSTRACT

Morphometrics, the study of the variation and change in form amongst organisms, serves as a basic methodological tool in various fields of biological research, including systematics. Because it includes information about spatial relationships amongst anatomical landmarks, geometric morphometrics is more suitable for analyzing morphometric variation than methods based on distance measurements.
Geometric morphometrics allows us to answer general ecological and evolutionary questions about shape.
In this paper, landmark‐based methods are described and illustrated, based on a dataset of measurements from 295 Apodemus mandibles, and the applications of such methods in the systematics of insectivores (Eulipotyphla) and rodents (Rodentia) are summarized.
European rabbit population trends and associated factors: a review of the situation in the Iberian Peninsula
Authors: DELIBES‐MATEOS MIGUEL , FERRERAS PABLO , VILLAFUERTE RAFAEL 
Published: February 2009

ABSTRACT

European rabbits are considered a keystone species in the Iberian Peninsula. Their populations have sharply declined over the past century, mainly due to habitat loss and the arrival of two viral diseases: myxomatosis in the 1950s and rabbit haemorrhagic disease (RHD) at the end of the 1980s. For the conservation of the Iberian Mediterranean ecosystem, it is important to determine whether rabbit populations are recovering two decades after the RHD outbreak, and to identify the factors associated with population recovery.
Here, we review the current knowledge on recent rabbit population trends in the Iberian Peninsula and the factors associated with these trends.
Although most rabbit populations are still declining in the Iberian Peninsula, a few seem to have recovered. In general, positive trends have been recorded in species‐friendly habitats characterized by non‐fragmented landscapes, interspersed patches of Mediterranean scrubland, good pastures and/or crops, soft soils that are suitable for warren construction and a Mediterranean climate with relatively high rainfall. Additionally, rabbits seem to be recovering better in areas where management practices (e.g. low hunting pressure, habitat management and predator control) are applied to increase their numbers.
From these findings, it is possible to identify five broad objectives for rabbit conservation in the Iberian Peninsula. First, it is clearly necessary to establish a long‐term programme for monitoring rabbit abundance and trends on a large scale. Second, the conservation and restoration of open Mediterranean scrubland should be a priority for stabilizing and maintaining existing healthy rabbit populations. Third, despite the lack of experimental evidence, management activities aimed at increasing the quantity and quality of both refuge and food should continue to be implemented. Fourth, legislation on the timing of the hunting season should be revisited following recommendations made by scientists. Finally, experimental approaches are required to investigate whether the control of generalist predators is a successful strategy to allow rabbit populations to recover.
More Vaccine Efficacy Studies on the Recombinant Bacille Calmette‐Guerin Co‐expressing Ag85B, Mpt64190–198 and Mtb8.4
Authors: Qie Y. Q. , Wang J. L. , Liu W. , Shen H. , Chen J. Z. , Zhu B. D. , Xu Y. , Zhang X. L. , Wang H. H. 
Published: February 2009

AbstractThe immunogenicity of the recombinant Bacille Calmette‐Guerin: rBCG‐Ag85B‐Mpt64190–198‐Mtb8.4 (rBCG‐AMM) was evaluated in our previous study. This paper compares the protective efficacy of rBCG‐AMM, rBCG‐A which overexpresses Ag85B and BCG in C57BL/6 mice. There was no significant difference in proliferation characteristics among rBCG‐AMM, rBCG‐A and BCG. The growth characteristics of rBCG‐AMM in host tissue were identical to control BCG, suggesting the improved protective efficacy was directly related to the expression of the Ag85B‐Mpt64190–198‐Mtb8.4 fusion protein. The protective experiment demonstrated that rBCG‐AMM could confer similar or even better protective efficacy against Mycobacterium tuberculosis infection compared with BCG or rBCG‐A as evaluated by bacterial organ loads, lung histopathology and net weight gain or loss. The results suggested that the recombinant BCG: rBCG‐Ag85B‐Mpt64190–198‐Mtb8.4 is a potential vaccine candidate for further study.
Differential Activation of Dendritic Cells by Toll‐like Receptor Agonists Isolated from the Gram‐positive Vaccine Vector Streptococcus gordonii
Authors: Mayer M. L. , Phillips C. M. , Townsend R. A. , Halperin S. A. , Lee S. F. 
Published: February 2009

AbstractThe oral commensal bacterium Streptococcus gordonii has been gathering interest as a candidate live mucosal vaccine delivery vector. S. gordonii has been shown to be capable of activating antigen presenting immune cells in a manner which leads to their activation and maturation, yet the mechanism used by S. gordonii to do so is poorly understood. The aim of this work was to investigate the immunostimulatory components of S. gordonii in inducing murine dendritic cell (DC) activation and maturation. Lipoteichoic acid (LTA), lipoprotein (LP), peptidoglycan (PGN), and DNA were isolated from S. gordonii, and used to stimulate murine DC. Cytokine production and DC surface marker upregulation in response to the bacterial components was quantified by enzyme‐linked immunosorbent assay and flow cytometry respectively. The results were contrasted against data obtained from DC derived from MyD88, TRIF [TIR(Toll/Interleukin‐1 Receptor)‐domain‐containing adapter‐inducing interferon‐beta] or toll‐like receptor‐2 (TLR‐2) knockout mice. The four S. gordonii bacterial components were found to differentially induce cytokine production and surface marker upregulation by murine DC. Activation of DC by both whole S. gordonii cells and the four bacterial components was abrogated in the absence of MyD88, but not in the absence of TRIF. LTA, LP and PGN, but not DNA and whole S. gordonii, required TLR‐2 to induce a DC response. The results collectively indicate that S. gordonii activates DC predominantly through a MyD88‐dependent and TRIF‐independent pathway. This activation can be attributed to multiple immunostimulatory components present within S. gordonii bacterial cells.
Levels of Urinary Complement Factor H in Patients with IgA Nephropathy are Closely Associated with Disease Activity
Authors: Zhang J.‐J. , Jiang L. , Liu G. , Wang S.‐X. , Zou W.‐Z. , Zhang H. , Zhao M.‐H. 
Published: February 2009

AbstractFactor H plays a key inhibitory role in control of the activation of alternative pathway of complement system. The aim of the study was to investigate the predictive value of factor H as a biomarker of renal injury in IgA nephropathy (IgAN). Urine factor H concentration from 202 patients was measured and compared with that of 60 healthy volunteers. Forty‐eight patients fulfilled Haas‐I or II (group 1), 60 fulfilled Haas‐III (group 2) and 94 fulfilled Haas‐IV or V (group 3). Co‐deposition of factor H and C3b in kidneys were investigated using confocal microscope. The levels of urinary factor H, when expressed as a ratio of urinary creatinine, were significantly higher in groups 3 than group 1 and 2, also significantly higher in group 2 than group 1. In addition, the levels of urinary factor H were significantly higher in those with factor H deposition in the kidney than those without deposition. The levels of urinary factor H may be a useful biomarker to evaluate kidney injury in IgAN.
Protein Tyrosine Phosphatase ε is a Negative Regulator of FcεRI‐mediated Mast Cell Responses
Authors: Akimoto M. , Mishra K. , Lim K.‐T. , Tani N. , Hisanaga S.‐i. , Katagiri T. , Elson A. , Mizuno K. , Yakura H. 
Published: February 2009

AbstractModulation of mast‐cell activation may provide novel ways to control allergic diseases. Here, we show that protein tyrosine phosphatase ε (PTPε; Ptpre) plays key regulatory roles during mast‐cell activation mediated by the high‐affinity IgE receptor (FcεRI). Bone marrow‐derived mast cells (BMMC) from Ptpre−/− mice exhibited enhanced FcεRI‐induced Ca2+ mobilization and mitogen‐activated protein kinase (MAPK) (JNK and p38) activation, and showed corresponding enhancement of evoked degranulation and cytokine production, but not leukotriene production. Examination of proteins linking tyrosine kinase activation and Ca2+ mobilization revealed that the absence of PTPε leads to increased phosphorylation of the linker for activation of T cells and SH2 domain‐containing leucocyte phosphoproteins of 76 kDa, but not Grb2‐associated binder‐2 (Gab2). Because Gab2 is considered to be situated downstream of Fyn kinase, we reasoned that Fyn may not be a target of PTPε. In the event, Syk but not Lyn was hyperphosphorylated in PTPε‐deficient BMMC. Thus, PTPε most likely exerts its effects at the level of Syk, inhibiting downstream events including phosphorylation of SLP‐76 and linker of activated T cells and mobilization of Ca2+. Consistent with the in vitro data, antigen‐ and IgE‐mediated passive systemic anaphylactic reactions were augmented in Ptpre−/− mice. Given that the number of mast cells is unchanged in these mice, this observation most likely reflects alterations of mast cell‐autonomous signalling events. These data suggest that PTPε negatively regulates FcεRI‐mediated signalling pathways and thus constitutes a novel target for ameliorating allergic conditions.
Aspects of B‐Cell Non‐Hodgkin’s Lymphoma Development: A Transition from Immune‐Reactivity to Malignancy
Authors: Illes A. , Varoczy L. , Papp G. , Wilson P. C. , Alex P. , Jonsson R. , Kovacs T. , Konttinen Y. T. , Zeher M. , Nakken B. , Szodoray P. 
Published: February 2009

AbstractThe development of B‐cell lymphomas is an intricate interplay among various pathogenic factors, leading to a multi‐step process, encompassing various stages of B‐cell maturation. Besides genetic abnormalities, a variety of environmental and microbial factors, as well as disproportional immune‐regulatory processes lead to the malignant transformation. Yet, little is known about the exact chain of events, which lead from the physiological polyclonal B‐cell activation as a response to exogenous antigens through oligoclonality to a monoclonal, uncontrolled, malignant B‐cell proliferation. The aim of the present review was to summarize the potential harmful steps in the development of B‐cell lymphomas, according to conventional and novel theories, and to depict therapeutic regimens presently in use as well as to envision future drug developments, beneficial in the battle against this lymphoid malignancy.
United airways again: high prevalence of rhinosinusitis and nasal polyps in bronchiectasis
Authors: Guilemany J. M. , Angrill J. , Alobid I. , Centellas S. , Pujols L. , Bartra J. , Bernal‐Sprekelsen M. , Valero A. , Picado C. , Mullol J. 
Published: February 2009

Background:  Although various relationships between the lower and upper airways have been found, the association of bronchiectasis with chronic rhinosinusitis and nasal polyps has not been thoroughly evaluated. This study was undertaken to examine the association of idiopathic and postinfective bronchiectasis with chronic rhinosinusitis and nasal polyposis.Methods:  In a prospective study, 56 patients with idiopathic and 32 with postinfective bronchiectasis were evaluated for chronic rhinosinusitis and nasal polyposis by using EP3OS criteria and assessing: symptoms score, nasal endoscopy, sinonasal and chest CT scan, nasal and lung function and nasal and exhaled NO.Results:  Most bronchiectasis patients (77%) satisfied the EP3OS criteria for chronic rhinosinusitis, with anterior (98.5%) and posterior (91%) rhinorrhea and nasal congestion (90%) being the major symptoms. Patients presented maxillary, ethmoidal and ostiomeatal complex occupancy with a total CT score of 8.4 ± 0.4 (0–24). Using endoscopy, nasal polyps with a moderate score of 1.6 ± 0.1 (0–3) were found in 25% of patients. Nasal NO was significantly lower in patients with nasal polyposis (347 ± 62 ppb) than in those without them (683 ± 76 ppb; P < 0.001), and inversely correlated (R = −0.36; P < 0.01) with the ostiomeatal complex occupancy. In the chest CT scan, patients with chronic rhinosinusitis showed a higher bronchiectasis severity score (7.2 ± 0.5; P < 0.001) than patients without (3.7 ± 0.7). The prevalence of chronic rhinosinusitis, nasal polyps and other outcomes were similar in idiopathic and postinfective bronchiectasis.Conclusions:  The frequent association of chronic rhinosinusitis and nasal polyposis with idiopathic and postinfective BQ supports the united airways concept, and it suggests that the two type of bronchiectasis share common etiopathogenic mechanisms.