bluuebunny/crossref_metadata_2025_split huggingface dataset:
The net carbon flux due to deforestation and forest re‐growth in the Brazilian Amazon: analysis using a process‐based model
Authors: Hirsch Adam I. , Little William S. , Houghton Richard A. , Scott Neal A. , White Joseph D. 
Published: May 2004

AbstractWe developed a process‐based model of forest growth, carbon cycling and land‐cover dynamics named CARLUC (for CARbon and Land‐Use Change) to estimate the size of terrestrial carbon pools in terra firme (nonflooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study the impact of Amazonian deforestation, selective logging and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re‐growth over the period from 1970 to 1998. We calculate that the net flux to the atmosphere during this period reached a maximum of ∼0.35 PgC yr−1 (1 PgC= 1 × 1015 gC) in 1990, with a cumulative release of ∼7 PgC from 1970 to 1998. The net flux is higher than predicted by an earlier study (Houghton et al., 2000) by a total of 1 PgC over the period 1989–1998 mainly because CARLUC predicts relatively high mature forest carbon storage compared with the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by∼1 PgC from 1970 to 1998, while different assumptions about land‐cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte‐Carlo approach, is roughly 35% of the mean value (1 SD).
Seasonal differences in isoprene and light‐dependent monoterpene emission by Amazonian tree species
Authors: Kuhn U. , Rottenberger S. , Biesenthal T. , Wolf A. , Schebeske G. , Ciccioli P. , Brancaleoni E. , Frattoni M. , Tavares T. M. , Kesselmeier J. 
Published: May 2004

AbstractWhereas for extra‐tropical regions model estimates of the emission of volatile organic compounds (VOC) predict strong responses to the strong annual cycles of foliar biomass, light intensity and temperature, the tropical regions stand out as a dominant source year round, with only little variability mainly due to the annual cycle of foliar biomass of drought‐deciduous trees. As part of the Large Scale Biosphere Atmosphere Experiment in Amazônia (LBA‐EUSTACH), a remote secondary tropical forest site was visited in the dry‐to‐wet season transition campaign, and the trace gas exchange of a strong isoprene emitter and a monoterpene emitter are compared to the wet‐to‐dry season transition investigations reported earlier. Strong seasonal differences of the emission capacity were observed. The standard emission factor for isoprene emission of young mature leaves of Hymenaea courbaril was about twofold in the end of the dry season (111.5 μgC g−1 h−1 or 41.2 nmol m−2 s−1) compared to old mature leaves investigated in the end of the wet season (45.4 μgC g−1 h−1 or 24.9 nmol m−2 s−1). Standardized monoterpene emission rate of Apeiba tibourbou were 2.1 and 3.6 μgC g−1 h−1 (or 0.3 and 0.8 nmol m−2 s‐1), respectively. This change in species‐specific VOC emission capacity was mirrored by a concurrent change in the ambient mixing ratios. The growth conditions vary less in tropical areas than in temperate regions of the world, and the seasonal differences in emission strength could not be reconciled solely with meteorological data of instantaneous light intensity and temperature. Hence the inadequacy of using a single standard emission factor to represent an entire seasonal cycle is apparent. Among a host of other potential factors, including the leaf developmental stage, water and nutrient status, and abiotic stresses like the oxidative capacity of the ambient air, predominantly the long‐term growth temperature may be applied to predict the seasonal variability of the isoprene emission capacity. The dry season isoprene emission rates of H. courbaril measured at the canopy top were also compared to isoprene emissions of the shade‐adapted species Sorocea guilleminiana growing in the understory. Despite the difference in VOC emission composition and canopy position, one common algorithm was able to predict the diel emission pattern of all three tree species.
Amazon drought and its implications for forest flammability and tree growth: a basin‐wide analysis
Authors: Nepstad Daniel , Lefebvre Paul , Lopes da Silva Urbano , Tomasella Javier , Schlesinger Peter , Solórzano Luiz , Moutinho Paulo , Ray David , Guerreira Benito José 
Published: May 2004

AbstractSevere drought in moist tropical forests provokes large carbon emissions by increasing forest flammability and tree mortality, and by suppressing tree growth. The frequency and severity of drought in the tropics may increase through stronger El Niño Southern Oscillation (ENSO) episodes, global warming, and rainfall inhibition by land use change. However, little is known about the spatial and temporal patterns of drought in moist tropical forests, and the complex relationships between patterns of drought and forest fire regimes, tree mortality, and productivity. We present a simple geographic information system soil water balance model, called RisQue (Risco de Queimada – Fire Risk) for the Amazon basin that we use to conduct an analysis of these patterns for 1996–2001. RisQue features a map of maximum plant‐available soil water (PAWmax) developed using 1565 soil texture profiles and empirical relationships between soil texture and critical soil water parameters. PAW is depleted by monthly evapotranspiration (ET) fields estimated using the Penman–Monteith equation and satellite‐derived radiation inputs and recharged by monthly rain fields estimated from 266 meteorological stations. Modeled PAW to 10 m depth (PAW10 m) was similar to field measurements made in two Amazon forests. During the severe drought of 2001, PAW10 m fell to below 25% of PAWmax in 31% of the region's forests and fell below 50% PAWmax in half of the forests. Field measurements and experimental forest fires indicate that soil moisture depletion below 25% PAWmax corresponds to a reduction in leaf area index of approximately 25%, increasing forest flammability. Hence, approximately one‐third of Amazon forests became susceptible to fire during the 2001 ENSO period. Field measurements also suggest that the ENSO drought of 2001 reduced carbon storage by approximately 0.2 Pg relative to years without severe soil moisture deficits. RisQue is sensitive to spin‐up time, rooting depth, and errors in ET estimates. Improvements in our ability to accurately model soil moisture content of Amazon forests will depend upon better understanding of forest rooting depths, which can extend to beyond 15 m. RisQue provides a tool for early detection of forest fire risk.
A land cover map of South America
Authors: Eva Hugh D. , Belward Alan S. , De Miranda Evaristo E. , Di Bella Carlos M. , Gond Valéry , Huber Otto , Jones Simon , Sgrenzaroli Matteo , Fritz Steffen 
Published: May 2004

AbstractA digital land cover map of South America has been produced using remotely sensed satellite data acquired between 1995 and the year 2000. The mapping scale is defined by the 1 km spatial resolution of the map grid‐cell. In order to realize the product, different sources of satellite data were used, each source providing either a particular parameter of land cover characteristic required by the legend, or mapping a particular land cover class. The map legend is designed both to fit requirements for regional climate modelling and for studies on land cover change. The legend is also compatible with a wider, global, land cover mapping exercise, which seeks to characterize the world's land surface for the year 2000. As a first step, the humid forest domain has been validated using a sample of high‐resolution satellite images. The map demonstrates both the major incursions of agriculture into the remaining forest domains and the extensive areas of agriculture, which now dominate South America's grasslands.
Comparison of the mass and energy exchange of a pasture and a mature transitional tropical forest of the southern Amazon Basin during a seasonal transition
Authors: Priante‐Filho Nicolau , Vourlitis George L. , Hayashi Mauro Massao Shiota , Nogueira José De Souza , Campelo José Holanda , Nunes Paulo César , Souza Luciana Sanches E , Couto Eduardo Guimarães , Hoeger Wander , Raiter Fernando , Trienweiler Jansen Luiz , Miranda Eduardo Jacusiel , Priante Pedro Correto , Fritzen Clóvis Lasta , Lacerda Moacir , Pereira Luiz Carlos , Biudes Marcelo Sacardi , Suli George Sanches , Shiraiwa Shozo , Paulo Sérgio Roberto Do , Silveira Marcos 
Published: May 2004

AbstractThis research utilized tower‐based eddy covariance to quantify the trends in net ecosystem mass (CO2 and H2O vapor) and energy exchange of important land‐cover types of NW Mato Grosso during the March–December 2002 seasonal transition. Measurements were made in a mature transitional (ecotonal) tropical forest near Sinop, Mato Grosso, and a cattle pasture near Cotriguaçú, Mato Grosso, located 500 km WNW of Sinop. Pasture net ecosystem CO2 exchange (NEE) was considerably more variable than the forest NEE over the seasonal transition, and the pasture had significantly higher rates of maximum gross primary production in every season except the dry–wet season transition (September–October). The pasture also had significantly higher rates of whole‐ecosystem dark respiration than the forest during the wetter times of the year. Average (±95% CI) rates of total daily NEE during the March–December 2002 measurement period were 26±15 mmol m−2 day−1 for the forest (positive values indicate net CO2 loss by the ecosystem) and −38±26 mmol m−2 day−1 for the pasture. While both ecosystems partitioned more net radiation (Rn) into latent heat flux (Le), the forest had significantly higher rates of Le and lower rates of sensible heat flux (H) than the pasture; a trend that became more extreme during the onset of the dry season. Large differences in pasture and forest mass and energy exchange occurred even though seasonal variations in micrometeorology (air temperature, humidity, and radiation) were relatively similar for both ecosystems. While the short measurement period and lack of spatial replication limit the ability to generalize these results to pasture and forest regions of the Amazon Basin, these results suggest important differences in the magnitude and seasonal variation of NEE and energy partitioning for pasture and transitional tropical forest.
CO2 flux from soil in pastures and forests in southwestern Amazonia
Authors: Salimon C. I. , Davidson E. A. , Victoria R. L. , Melo A. W. F. 
Published: May 2004

AbstractStocks of carbon in Amazonian forest biomass and soils have received considerable research attention because of their potential as sources and sinks of atmospheric CO2. Fluxes of CO2 from soil to the atmosphere, on the other hand, have not been addressed comprehensively in regard to temporal and spatial variations and to land cover change, and have been measured directly only in a few locations in Amazonia. Considerable variation exists across the Amazon Basin in soil properties, climate, and management practices in forests and cattle pastures that might affect soil CO2 fluxes. Here we report soil CO2 fluxes from an area of rapid deforestation in the southwestern Amazonian state of Acre. Specifically we addressed (1) the seasonal variation of soil CO2 fluxes, soil moisture, and soil temperature; (2) the effects of land cover (pastures, mature, and secondary forests) on these fluxes; (3) annual estimates of soil respiration; and (4) the relative contributions of grass‐derived and forest‐derived C as indicated by δ13CO2. Fluxes were greatest during the wet season and declined during the dry season in all land covers. Soil respiration was significantly correlated with soil water‐filled pore space but not correlated with temperature. Annual fluxes were higher in pastures compared with mature and secondary forests, and some of the pastures also had higher soil C stocks. The δ13C of CO2 respired in pasture soils showed that high respiration rates in pastures were derived almost entirely from grass root respiration and decomposition of grass residues. These results indicate that the pastures are very productive and that the larger flux of C cycling through pasture soils compared with forest soils is probably due to greater allocation of C belowground. Secondary forests had soil respiration rates similar to mature forests, and there was no correlation between soil respiration and either forest age or forest biomass. Hence, belowground allocation of C does not appear to be directly related to the stature of vegetation in this region. Variation in seasonal and annual rates of soil respiration of these forests and pastures is more indicative of flux of C through the soil rather than major net changes in ecosystem C stocks.
Globally significant changes in biological processes of the Amazon Basin: results of the Large‐scale Biosphere–Atmosphere Experiment
Authors: Davidson Eric A. , Artaxo Paulo 
Published: May 2004

AbstractThe Amazon River, its huge basin, and the changes in biological processes that are rapidly occurring in this region are unquestionably of global significance. Hence, Global Change Biology is delighted to host a special thematic issue devoted to the Large‐scale Biosphere–Atmosphere Experiment in Amazônia (LBA), which is a multinational, interdisciplinary research program led by Brazil. The goal of LBA is no less modest than its subject: to understand how Amazônia functions as a regional entity in the Earth system and how these functions are changing as a result of ongoing changes in land use. This compilation of 26 papers resulting from LBA‐related research covers a broad range of topics: forest stocks of carbon (C) and nitrogen (N); fluxes of greenhouse gases and volatile organic compounds from vegetation, soils and wetlands; mapping and modeling land‐use change, fire risk, and soil properties; measuring changes caused by logging, pasturing and cultivating; and new research approaches in meteorology to estimate nocturnal fluxes of C from forests and pastures. Some important new synthesis can be derived from these and other studies. The aboveground biomass of intact Amazonian forests appears to be a sink for atmospheric carbon dioxide (CO2), while the wetlands and soils are a net source of atmospheric methane (CH4) and nitrous oxide (N2O), respectively. Land‐use change has, so far, had only a minor effect on basin‐wide emissions of CH4 and N2O, but the net effect of deforestation and reforestation appears to be a significant net release of CO2 to the atmosphere. The sum of the 100‐year global warming potentials (GWP) of these annual sources and sinks of CH4, N2O, and CO2 indicate that the Amazonian forest–river system currently may be nearly balanced in terms of the net GWP of these biogenic atmospheric gases. Of course, large uncertainties remain for these estimates, but the papers published here demonstrate tremendous progress, and also large remaining hurdles, in narrowing these uncertainties in our understanding of how Amazônia functions as a regional entity in the Earth system.
Quantitative DNA Fingerprinting May Distinguish New Primary Breast Cancer From Disease Recurrence
Authors: Schlechter Benjamin L. , Yang Qiong , Larson Pamela S. , Golubeva Arina , Blanchard Rita A. , de Las Morenas Antonio , Rosenberg Carol L. 
Published: May 2004

Purpose Approximately 10% of women with breast cancer develop a second breast tumor, either a new primary or a recurrence. Differentiating between these entities using standard clinical and pathologic criteria remains challenging. Ambiguous cases arise, and misclassifications may occur. We investigated whether quantitative DNA fingerprinting, based on allele imbalance (AI) or loss of heterozygosity (LOH), could evaluate clonality and distinguish second primary breast cancer from recurrence. Methods We developed a scoring system based on the AI/LOH fingerprints of 20 independent breast tumors and generated a decision rule to classify any breast tumor pair as related or unrelated. We validated this approach on eight related tumors (cancers and synchronous positive lymph nodes). Finally, we analyzed paired tumors from 13 women (bilateral cancers, primary tumors and contralateral positive axillary lymph nodes, or two ipsilateral tumors). Each pair's genetic classification was compared with their clinical diagnosis and outcome. Results Each independent cancer had a unique fingerprint. Every tumor pair's relationship was quantifiable. Six of eight related tumor pairs were genetically classified correctly, two were indeterminate, and none were misclassified. Among the 13 women with two cancers, four of five clinically indeterminate pairs could be classified genetically. In three of 13 women, the pair's classification contradicted the clinical diagnosis. These women had bilateral cancers genetically classified as related and disease progression. This challenges the paradigm that bilateral cancers represent independent tumors. Overall, women with tumors genetically classified as related had poorer outcomes. Conclusion Quantitative AI/LOH fingerprinting is a potentially valuable tool to improve diagnosis and optimize treatment for the growing number of second breast malignancies.
Subclinical Late Cardiomyopathy After Doxorubicin Therapy for Lymphoma in Adults
Authors: Hequet O. , Le Q.H. , Moullet I. , Pauli E. , Salles G. , Espinouse D. , Dumontet C. , Thieblemont C. , Arnaud P. , Antal D. , Bouafia F. , Coiffier B. 
Published: May 2004

Purpose To assess the cardiac status of the long-term survivors and to estimate the incidence and the features of subclinical cardiotoxicity induced after conventional treatment with doxorubicin for non-Hodgkin's lymphoma or Hodgkin's lymphoma. Patients and Methods We analyzed a group of patients who previously received doxorubicin-based chemotherapy for lymphoma. Echocardiograms were performed at least 5 years after therapy with anthracyclines. Clinical cardiomyopathy was defined by the presence of clinical signs of congestive heart failure (CHF). Subclinical cardiomyopathy was defined by decrease of left ventricular fractional shortening (FS) without clinical signs of CHF. Cumulative dose of doxorubicin, male sex, older age, relapse, radiotherapy (mediastinal or total-body irradiation), autologous stem-cell transplantation, high-dose cyclophosphamide, and cardiovascular risk factors (hypertension, diabetes, hypercholesterolemia, familial history of cardiac disease, being overweight, and smoking history) were evaluated as potential risk factors for the development of cardiac dysfunction. Results Of 141 assessable patients (median age, 54 years; median cumulative dose of doxorubicin, 300 mg/m2), only one developed CHF. Criteria of subclinical cardiomyopathy were found in 39 patients. In multivariate analysis, factors that contributed to decreased FS were male sex (P < .01), older age (P < .01), higher cumulative dose of doxorubicin or association with another anthracycline (P = .04), radiotherapy (P = .04), and being overweight (P = .04). Conclusion Cardiac abnormalities can occur in patients treated with doxorubicin for lymphoma in the absence of CHF, even in patients who received moderate anthracycline doses. Male sex, older age, higher dose of doxorubicin, radiotherapy, and being overweight were risk factors for the development of cardiomyopathy.
Quality of Abstracts Describing Randomized Trials in the Proceedings of American Society of Clinical Oncology Meetings: Guidelines for Improved Reporting
Authors: Krzyzanowska Monika K. , Pintilie Melania , Brezden-Masley Christine , Dent Rebecca , Tannock Ian F. 
Published: May 2004

Purpose To evaluate the quality of reporting in abstracts describing randomized controlled trials (RCTs) included in the Proceedings of American Society of Clinical Oncology (ASCO) meetings and to propose reporting guidelines for abstracts that are submitted to future meetings. Methods Guidelines for reporting of RCTs in abstracts were developed by extracting key elements from published guidelines for full reports of RCTs, and modified based on an expert survey. Abstracts presenting results of RCTs with sample size ≥ 200 were identified from the ASCO Proceedings for the years 1989 to 1998. Information regarding the quality of each abstract was extracted, and a quality score (possible range, 0 to 10) was assigned based on adherence to the guidelines. Results Brief description of the intervention, explicit identification of the primary end point, and presentation of results accompanied by statistical tests were regarded by experts as the most important items to include in an abstract, whereas presentation of secondary and subgroup analyses was the least important. Deficiencies in reporting were present in almost all of the 510 abstracts; for example, only 22% of the abstracts provided explicit identification of the primary end point. The median quality score was 5.5 (range, 2.0 to 8.5); the quality score improved with time (P < .0001) and was better for oral or plenary presentations (P = .0003). Conclusion The quality of reporting of RCTs in abstracts submitted to Annual Meetings of ASCO is suboptimal. Although space precludes the inclusion of details required in the final report, abstracts could be improved through the use of explicit minimal guidelines, which are suggested in this article.
Effect of Dose on Immune Response in Patients Vaccinated With an HER-2/neu Intracellular Domain Protein—Based Vaccine
Authors: Disis Mary L. , Schiffman Kathy , Guthrie Katherine , Salazar Lupe G. , Knutson Keith L. , Goodell Vivian , dela Rosa Corazon , Cheever Martin A. 
Published: May 2004

PurposeTo evaluate the safety of an HER-2/neu intracellular domain (ICD) protein vaccine and to estimate whether vaccine dose impacts immunogenicity.Patients and MethodsTwenty-nine patients with HER-2/neu—overexpressing breast or ovarian cancer and with no evidence of disease after standard therapy received a low- (25 μg), intermediate- (150 μg), or high-dose (900 μg) HER-2/neu ICD protein vaccine. The vaccine was administered intradermally, monthly for 6 months, with granulocyte-macrophage colony-stimulating factor as an adjuvant. Toxicity and both cellular and humoral HER-2/neu—specific immunity was evaluated.ResultsThe vaccine was well tolerated. The majority of patients (89%) developed HER-2/neu ICD-specific T-cell immunity. The dose of vaccine did not predict the magnitude of the T-cell response. The majority of patients (82%) also developed HER-2/neu—specific immunoglobulin G antibody immunity. Vaccine dose did not predict magnitude or avidity of the HER-2/neu—specific humoral immune response. Time to development of detectable HER-2/neu—specific immunity, however, was significantly earlier for the high- versus low-dose vaccine group (P = .003). Over half the patients retained HER-2/neu—specific T-cell immunity 9 to 12 months after immunizations had ended.ConclusionThe HER-2/neu ICD protein vaccine was well tolerated and effective in eliciting HER-2/neu—specific T-cell and antibody immunity in the majority of breast and ovarian cancer patients who completed the vaccine regimen. Although the dose of vaccine did not impact the magnitude of T-cell or antibody immunity elicited, patients receiving the highest dose developed HER-2/neu—specific immunity more rapidly than those who received the lowest dose.