bluuebunny/crossref_metadata_2025 huggingface dataset:
Regionalization of methane emissions in the Amazon Basin with microwave remote sensing
Authors: Melack John M. , Hess Laura L. , Gastil Mary , Forsberg Bruce R. , Hamilton Stephen K. , Lima Ivan B.T. , Novo Evlyn M.L.M.
Published: May 2004

Wetlands of the Amazon River basin are globally significant sources of atmospheric methane. Satellite remote sensing (passive and active microwave) of the temporally varying extent of inundation and vegetation was combined with field measurements to calculate regional rates of methane emission for Amazonian wetlands. Monthly inundation areas for the fringing floodplains of the mainstem Solimões/Amazon River were derived from analysis of the 37 GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer from 1979 to 1987. L‐band synthetic aperture radar data (Japanese Earth Resources Satellite‐1) were used to determine inundation and wetland vegetation for the Amazon basin (<500 m elevation) at high (May–June 1996) and low water (October 1995). An extensive set of measurements of methane emission is available from the literature for the fringing floodplains of the central Amazon, segregated into open water, flooded forest and floating macrophyte habitats. Uncertainties in the regional emission rates were determined by Monte Carlo error analyses that combined error estimates for the measurements of emission and for calculations of inundation and habitat areas. The mainstem Solimões/Amazon floodplain (54–70°W) emitted methane at a mean annual rate of 1.3 Tg C yr−1, with a standard deviation (SD) of the mean of 0.3 Tg C yr−1; 67% of this range in uncertainty is owed to the range in rates of methane emission and 33% is owed to uncertainty in the areal estimates of inundation and vegetative cover. Methane emission from a 1.77 million square kilometers area in the central basin had a mean of 6.8 Tg C yr−1 with a SD of 1.3 Tg C yr−1. If extrapolated to the whole basin below the 500 m contour, approximately 22 Tg C yr−1 is emitted; this mean flux has a greenhouse warming potential of about 0.5 Pg C as CO2. Improvement of these regional estimates will require many more field measurements of methane emission, further examination of remotely sensed data for types of wetlands not represented in the central basin, and process‐based models of methane production and emission.
Radon fluxes in tropical forest ecosystems of Brazilian Amazonia: night‐time CO2 net ecosystem exchange derived from radon and eddy covariance methods
Authors: Martens Christopher S. , Shay Thomas J. , Mendlovitz Howard P. , Matross Daniel M. , Saleska Scott R. , Wofsy Steven C. , Stephen Woodward W. , Menton Mary C. , De Moura José M. S. , Crill Patrick M. , De Moraes Osvaldo L. L. , Lima Risonaldo L.
Published: May 2004

Radon‐222 (Rn‐222) is used as a transport tracer of forest canopy–atmosphere CO2 exchange in an old‐growth, tropical rain forest site near km 67 of the Tapajós National Forest, Pará, Brazil. Initial results, from month‐long periods at the end of the wet season (June–July) and the end of the dry season (November–December) in 2001, demonstrate the potential of new Rn measurement instruments and methods to quantify mass transport processes between forest canopies and the atmosphere. Gas exchange rates yield mean canopy air residence times ranging from minutes during turbulent daytime hours to greater than 12 h during calm nights. Rn is an effective tracer for net ecosystem exchange of CO2 (CO2 NEE) during calm, night‐time hours when eddy covariance‐based NEE measurements are less certain because of low atmospheric turbulence. Rn‐derived night‐time CO2 NEE (9.00±0.99 μmol m−2 s−1 in the wet season, 6.39±0.59 in the dry season) was significantly higher than raw uncorrected, eddy covariance‐derived CO2 NEE (5.96±0.51 wet season, 5.57±0.53 dry season), but agrees with corrected eddy covariance results (8.65±1.07 wet season, 6.56±0.73 dry season) derived by filtering out lower NEE values obtained during calm periods using independent meteorological criteria. The Rn CO2 results suggest that uncorrected eddy covariance values underestimate night‐time CO2 loss at this site. If generalizable to other sites, these observations indicate that previous reports of strong net CO2 uptake in Amazonian terra firme forest may be overestimated.
Patients’ experiences of being helped in an inpatient setting
Authors: KOIVISTO K. , JANHONEN S. , VÄISÄNEN L.
Published: May 2004

The purpose of this article is to describe patients’ experiences of being helped during a period of psychiatric hospital care. Psychosis has traditionally been defined in medical and psychological terminology. The focus of psychiatric nursing is the human experience of distress associated with mental illness. The aim of psychiatric care is to promote healing and coping in daily life through support, validation and understanding. The main aim is to re‐empower the patient with psychosis by using psychiatric care. The purposive sample consisted of interviews with nine voluntary patients recovering from psychosis. The interviewees told about their experiences of care. The verbatim transcripts were analysed using Giorgi's phenomenological method. Patients experienced care as helpful but unstructured: care facilitated their situation by alleviating the disorders, but it had not been defined by nurses, and the patients made their own conclusions about what care should be like. The care did not reach the inner world of the patients with psychosis. From the patients’ point of view, care should protect them from vulnerability and empower/restructure their selves for coping in daily life.
Mastery in patients with schizophrenia living in the community: relationship to sociodemographic and clinical characteristics, needs for care and support, and social network
Authors: BENGTSSON‐TOPS A.
Published: May 2004

In line with user involvement and empowerment in individuals who suffer from a severe mental illness, the sense of mastery is important. Few studies have investigated factors that contribute to mastery in individuals with schizophrenia. The aims of the present 18‐month follow‐up study were to investigate associations between mastery and clinical and sociodemographic factors, needs for care and support and social network, and to investigate whether changes in mastery were related to changes with regard to these aspects in a group of patients (n = 120) with schizophrenia living in the community. Structural interviews were performed at baseline and after 18 months. Pearlin's mastery scale, the Camberwell Assessment of Needs (CAN), the Interview Schedule for Social Interaction (ISSI), and the Brief Psychiatric Rating Scale (BPRS) were used on both interview occasions. A stepwise regression analysis showed a negative relationship between psychopathology, especially affective and negative symptoms, and mastery. Stronger mastery was associated with younger age and less severe basic needs. In total psychopathology, age and basic needs explained 50.7% of the variance in mastery. Changes in mastery were positively correlated to changes in access to social contact but negatively correlated to changes in affective symptoms. In order to target mastery in individuals with schizophrenia, the community‐based nursing services need to develop, implement, and evaluate interventions that are effective for psychiatric symptoms, social skills performance, and needs for care and support in areas of living, nutrition, and daytime activities.
Mental health practice and the rhetoric–reality gap
Authors: SKIDMORE D. , WARNE T. , STARK S.
Published: May 2004

This paper had its genesis in a national project, sponsored by the English National Board for Nursing, Midwifery and Health Visiting, to explore team working within mental health practice. The project extended over a 2‐year period and utilized various methods of data collection. However, this paper focused on data, from the national survey and informal interviews (based in eight regions), that addressed specific issues within the practitioner group. Of the 800 questionnaires sent out 26% were returned. Fifty‐three percent of the returns were from practitioners, 14% user/carers and 33% educationalists. Our focus was that of the practitioners. This group had a response rate of 50% (i.e. 50% of the surveys sent out to practitioners were returned). A content analysis of 100 interviews was used to triangulate the data. Whilst the original brief was to explore team working the survey also highlighted data that indicated a common understanding of what mental health practitioners do and what they say they do and that, although there was a commonality of vocabulary, different practices existed between and within regions. This is the focus of this paper. We argue, from our findings, that different practice is a result of ‘habitus’. Whilst practitioners reported that they subscribe to a national agreement of meaning, there is a rhetoric–reality gap: that which is said to be done is not what is, in fact, practised. At the local level we argue that working within the habitus (educationally) can address the rhetoric–reality gap. However, we recommend further studies in order to explore how working within the habitus can address this matter across regions.
Treating first episode psychosis – the service users’ perspective: a focus group evaluation
Authors: O'TOOLE M. S. , OHLSEN R. I. , TAYLOR T. M. , PURVIS R. , WALTERS J. , PILOWSKY L. S.
Published: May 2004

UK national guidance has prioritized developing specialist services for first episode psychosis. Such services are in the early stages of development and a definitive treatment model has yet to be established. The aim of this study was to explore service users’ experiences of a first episode intervention designed along evidence‐based ‘best practice’ guidelines and to establish specific elements seen as effective to help inform future service planning and provision. Twelve users of a specialist first episode service participated in focus groups. These were then analyzed using Interpretative Phenomenological Analysis, a specialized form of content analysis. Key elements identified by the service users included the ‘human’ approach as a key to the recovery process, being involved in treatment decisions, flexibility of appointments, high nurse to patient ratio, reduction in psychotic symptoms, increased confidence and independence and the provision of daily structure. To our knowledge, this is the first systematic qualitative evaluation of users’ experience of a specialist first episode treatment intervention. Our findings indicate that adherence to best practice guidelines was appreciated. Regular focus groups provide a continuous audit cycle incorporating service improvements in line with government recommendations, centrally informed by the service users’ and caregivers’ perspective.
Never good enough – part 2: clinical implications
Authors: CROWE M.
Published: May 2004

This paper is the second part of two papers that explore the affect of shame and its role in the manifestation of symptoms that could be regarded as evidence of mental disorder. The clinical implications for nursing a person with an overwhelming shame response are discussed in this paper. It is proposed that a discursive approach to nursing care may assist mental health nurses to provide care that best meets the needs of people experiencing these symptoms. The paper suggests that this nursing care involves recognizing the impact of shame; making connections between how the person has learned to cope with shame and their current mental distress; situating shame in its socio‐cultural context; focusing on subject–object differentiation and promoting acceptance of difference and exploring alternative subject positions for managing feelings of shame. The focus of these interventions is to encourage awareness of interactions with others, how the person positions her or his self in relation to others, and the communication patterns that perpetuate feelings of shame. It also involves helping the person to integrate the ideal image of her or his self with subject positions that are more flexible.
Never good enough – part 1: shame or borderline personality disorder?
Authors: CROWE M.
Published: May 2004

This paper takes a deconstructive approach to the historical, clinical, and social context of the diagnosis of borderline personality disorder (BPD). This is undertaken by providing an overview of pertinent literature, an examination of the diagnostic criteria, a discussion of the development of the shame affect, a discussion of women's narratives and a reinterpretation of the symptoms of BPD as an overwhelming shame response. An argument is developed that shame is an integral but neglected feature in the experiences of mental distress that are characteristic of BPD. This discussion is supported with evidence of shame in narrative quotes from women with a diagnosis of BPD. There are striking similarities between what is currently pathologized as BPD and an overwhelming shame response. Recognizing the influence of shame may assist mental health nurses to provide mental health nursing care that best meets the needs of women experiencing these symptoms.
In silico screening of a saturated mutation library of tomato
Authors: Menda Naama , Semel Yaniv , Peled Dror , Eshed Yuval , Zamir Dani
Published: May 2004

A comprehensive mutant population is a basic resource for exploring gene function. We developed an isogenic tomato ‘mutation library’ in the genetic background of the inbred variety M82. A total of 13 000 M2 families, derived from EMS (ethyl methane sulfonate) and fast‐neutron mutagenesis, were visually phenotyped in the field and categorized into a morphological catalog that includes 15 primary and 48 secondary categories. Currently, 3417 mutations have been cataloged; among them are most of the previously described phenotypes from the monogenic mutant collection of The Tomato Genetics Resource Center, and over a thousand new mutants, with multiple alleles per locus. The phenotypic database indicates that most mutations fall into more than a single category (pleiotropic), with some organs such as leaves more prone to alterations than others. All data and images can be searched and accessed in the Solanaceae Genome Network (SGN) on a site called ‘The Genes That Make Tomatoes’ (http://zamir.sgn.cornell.edu/mutants/).
Economic Determinants of Multiple Accounting Method Choices in a Swiss Context
Authors: Missonier‐Piera Franck
Published: May 2004

This article investigates economic determinants that may affect multiple accounting method choices made by Swiss listed companies. It intends to make a contribution to the accounting choice literature for at least four reasons. This is, to our knowledge, the first study to investigate the economic determinants of Swiss accounting method choices. Second, Swiss firms provide an interesting sample for testing accounting method choices because they can choose from a much wider range of accounting methods than their American counterparts. Third, this study examines the balance sheet effect as well as the income statement effect. Lastly, multiple accounting methods are used instead of individual choices. The empirical results exhibit that income‐accelerating accounting method choices is positively associated with the recourse to bank and private loans, the extent of assets specificity and the ownership dilution of the firm and negatively with labour force. Additionally, firms that select leverage‐ratios decreasing accounting methods, make higher recourse to debt and especially bank loans to finance their activities and exhibit a higher proportion of specific assets than other corporations. Overall, this result suggests that in a Swiss context, managers may select accounting methods to decrease both debt and political costs as well as to increase their own compensation to some extent.
Protozoa and plant growth: the microbial loop in soil revisited
Authors: Bonkowski Michael
Published: May 2004

All nutrients that plants absorb have to pass a region of intense interactions between roots, microorganisms and animals, termed the rhizosphere. Plants allocate a great portion of their photosynthetically fixed carbon to root‐infecting symbionts, such asmycorrhizal fungi; another part is released as exudates fuelling mainly free‐living rhizobacteria. Rhizobacteria are strongly top‐down regulated by microfaunal grazers, particularly protozoa. Consequently, beneficial effects of protozoa on plant growth have been assigned to nutrients released from consumed bacterial biomass, that is, the ‘microbial loop’. In recent years however, the recognition of bacterial communication networks, the common exchange of microbial signals with roots and the fact that these signals are used to enhance the efflux of carbon from roots have revolutionized our view of rhizosphere processes. Most importantly, effects of rhizobacteria on root architecture seem to be driven in large by protozoan grazers. Protozoan effects on plant root systems stand in sharp contrast to effects of mycorrhizal fungi. Because the regulation of root architecture is a key determinant of nutrient‐ and water‐use efficiency in plants, protozoa provide a model system that may considerably advance our understanding of the mechanisms underlying plant growth and community composition.
Understanding global teleconnections of climate to regional model estimates of Amazon ecosystem carbon fluxes
Authors: Potter Christopher , Klooster Steven , Steinbach Michael , Tan Pang‐Ning , Kumar Vipin , Shekhar Shashi , Carvalho Claudio Reis de
Published: May 2004

We have investigated global teleconnections of climate to regional satellite‐driven observations for prediction of Amazon ecosystem production, in the form of monthly estimates of net carbon exchange over the period 1982–1998 from the NASA–CASA (Carnegie–Ames–Stanford) biosphere model. This model is driven by observed surface climate and monthly estimates of vegetation leaf area index (LAI) and fraction of absorbed PAR (fraction of photosynthetically active radiation, FPAR) generated from the NOAA satellite advanced very high‐resolution radiometer (AVHRR) and similar sensors. Land surface AVHRR data processing using modified moderate‐resolution imaging spectroradiometer radiative transfer algorithms includes improved calibration for intra‐ and intersensor variations, partial atmospheric correction for gaseous absorption and scattering, and correction for stratospheric aerosol effects associated with volcanic eruptions. Results from our analysis suggest that anomalies of net primary production and net ecosystem production predicted from the NASA–CASA model over large areas of the Amazon region east of 60°W longitude are strongly correlated with the Southern Oscillation index. Extensive areas of the south‐central Amazon show strong linkages of the FPAR and the NASA–CASA anomaly record to the Arctic Oscillation index, which help confirm a strong relation to southern Atlantic climate anomalies, with associated impacts on Amazon rainfall patterns. Processes are investigated for these teleconnections of global climate to Amazon ecosystem carbon fluxes and regional land surface climate.
Soil databases and the problem of establishing regional biogeochemical trends
Authors: Holmes Karen W. , Roberts Dar A. , Sweeney Stuart , Numata Izaya , Matricardi Eraldo , Biggs Trent W. , Batista Getulio , Chadwick Oliver A.
Published: May 2004

Regional and global environmental modeling depend on soil data for input layers or parameterization. However, randomly located observations, such as provided by agricultural databases, are not always representative of trends identified in field studies conducted under carefully controlled conditions. Many researchers lament the paucity of soil profile data in Amazônia, and suggest that given more data, regional studies would more closely approximate field research results. We assess the ability of a well‐populated regional database collected in the southwestern Brazilian Amazon to reproduce expected biogeochemical trends associated with forest clearing and pasture establishment, and explore the ramifications of relying on independently collected soil data for regional modeling. The Soteron database includes analyses of approximately 3000 soil cores collected for zoning purposes in the state of Rondônia. Pasture ages were determined from a time series of Landsat TM images classified using spectral mixture analysis.

Although regional averages showed some of the temporal trends expected based on field study results (e.g. increase in pH following forest clearing), the trends were not statistically significant. Stratification by precipitation and other variables showed pasture age to be important but difficult to separate from other potential controls on soil conditions, mainly because of the reduced number of observations in each stratum. Using multiple regression, which permitted the inclusion of all potential explanatory factors and interactions, pasture age was shown to be a statistically significant predictor of soil conditions. However, the expected temporal sequence of changes documented by field chronosequence studies could not be reproduced. Properties dominated by large‐scale environmental gradients – pH, sum of base cations, aluminum saturation, and exchangeable calcium – were moderately well modeled, while those more strongly linked to dynamic spatially heterogeneous processes such as biological cycling and land management, particularly organic carbon and nitrogen, could not be modeled.

Management‐induced soil changes occur at too fine a scale to be captured by most maps, and the relative changes are small compared with spatial heterogeneity caused by controls on soil development over large regions. Therefore, regardless of whether chronosequence‐derived models of biogeochemical response to land‐cover change are correct, the results of these models will not lead to spatially explicit maps that can be validated by regional reconnaissance, nor will they facilitate realistic predictions of the regional biogeochemical consequences of land‐cover change. The change from local to regional scale entails a change in the relative importance of processes controlling soil property behavior.
Variation of carbon and nitrogen cycling processes along a topographic gradient in a central Amazonian forest
Authors: Luizão Regina C. C. , Luizão Flávio J. , Paiva Romilda Q. , Monteiro Terezinha F. , Sousa Lucinéia S. , Kruijt Bart
Published: May 2004

It is well recognized in the literature that topography can influence soil nutrient stocks and dynamics in temperate regions, but for tropical forests, this source of variation has sometimes been ignored. The nature of such variations may depend upon the soil type, which in turn, is closely linked to local or regional topography. This study characterizes the soil and describes the status of carbon and nitrogen in vegetation, litterfall, litter‐layer and soil upper layers along the main positions of a topographic gradient (plateau, slope and valley), 60 km north of Manaus, on Cuieiras Reserve watershed. Nitrogen concentrations in living leaves, fresh litterfall, litter‐layer and soil upper layers were lower in the valley than in both slope and plateau plots. Carbon concentrations in plant material were not significantly different among the three topographic positions, resulting in higher C : N ratios in valley plots. Local topography (plateau, slope and valley) clearly was an influential factor in the nutrient distribution along the study locations. Lower rates of N cycling processes in the valley are probably related to its sandy soil texture and seasonal flooding.
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

We 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

Whereas 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

Severe 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

A 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

This 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

Stocks 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

The 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.
Pulp canal obliteration in an unerupted permanent incisor following trauma to its primary predecessor: a case report
Authors: Katz‐Sagi Hadas , Moskovitz Moti , Moshonov Joshua , Holan Gideon
Published: May 2004

Abstract  – Trauma to a primary tooth may result in damage to the underlying developing permanent tooth bud because of the close proximity between the root of the primary tooth and its permanent successor. We report an unusual case where injury to the primary dentition resulted in pulp canal obliteration (PCO) of a permanent maxillary central incisor prior to its eruption. The other permanent maxillary central incisor was diagnosed as malformed because of trauma to the primary dentition at an earlier age. The occurrences of PCO or crown malformation dose not routinely disrupt the eruption of those teeth. Periodic assessment is required to determine the need for endodontic intervention.
In vitro assessment of dentinal permeability after the use of ultrasonic‐activated irrigants in the pulp chamber before internal dental bleaching
Authors: Carrasco Laise Daniela , Pécora Jesus Djalma , Fröner Izabel Cristina
Published: May 2004

Abstract  – This in vitro study aimed to assess dentin permeability quantitatively after the use of different irrigants into the pulp chamber, with or without ultrasonic activation, before the application of an internal bleaching agent. Thirty maxillary anterior teeth, treated endodontically, were randomly assigned to six groups, according to the irrigant used: group I, distilled water; group II, 17% EDTA; group III, 1% sodium hypochlorite; for groups IV, V, and VI, respectively, the same solutions were used, but were ultrasonicated. In groups I, II, and III, the irrigant that filled the pulp chamber was left undisturbed for 15 s and was then aspirated; in groups IV, V, and IV, the irrigants were placed into the pulp chamber, ultrasonic‐activated for 15 s, and were then aspirated. This sequence was repeated three times for all groups. Afterwards, for all groups, the pulp chamber was dried, filled with a bleaching agent, and sealed with glass ionomer cement. At each change of the whitening agent, these procedures were repeated. Then, the temporary restorations were removed, access cavities were cleaned, and teeth were immersed in a 10% copper sulfate aqueous solution, submitted to vacuum and immersed in a 1% rubianic acid alcohol solution. Copper ion penetration was revealed by the rubianic acid. After staining, roots were removed at the cemento‐enamel junction (CEJ) and sectioned in a mesiodistal direction starting from the cervical plug level. The sections were thinned, observed under an optical microscope, the images were digitized, and copper ion penetration was measured in each section using a specific software. Means and SD were: group I, 2.41 (±1.45); group II, 5.22 (±1.79); group III, 8.32 (±2.55); group IV, 3.73 (±0.89); group V, 14.83 (±4.99); and group VI, 10.51 (±2.65). Statistical analysis using two‐way anova and Tukey test showed that, regardless of the irrigant, ultrasonication increased dentinal permeability (P < 0.01). Comparing the overall effectiveness of the tested solutions, EDTA yielded the greatest increase in dentinal permeability (P < 0.01). Based on these results, it may be concluded that use of ultrasonic‐activated irrigants in the pulp chamber, before the accomplishment of internal dental bleaching procedures, may result in a remarkable increase of dentin permeability, which may enhance the efficiency of the whitening agent.
Incidence of cerebral concussions associated with type of mouthguard used in college football
Authors: Wisniewski John F. , Guskiewicz Kevin , Trope Martin , Sigurdsson Asgeir
Published: May 2004

Abstract –  Controversy exists among sports dentists as to whether or not a ‘custom made’ mouthguard is more effective in reducing the incidence of cerebral concussion than the boil‐and‐bite ‘non‐custom made’ mouthguard. While members on each side remain steadfast in their opinion, not a single epidemiological study has been conducted to investigate the effect of type of mouthguard worn on the incidence of cerebral concussion. The aim of this study was to determine if there was a difference between the type of mouthguard worn and the incidence of cerebral concussions among National Collegiate Athletic Association (NCAA) Division I‐A football players. During the 15‐week 2001 college football season, trainers entered, via an interactive web site, weekly data for each game and practice sessions for the preceding week. Eighty‐seven (76%) out of a possible 114 Division I teams participated. A total of 506 297 athletic exposures were recorded; 369 brain concussions were reported. The incidence of cerebral concussions per 1000 exposures was 0.73. Utilizing a risk ratio with a 95% confidence interval, no statistical difference occurred in the incidence of cerebral concussions between football players wearing custom made versus non‐custom made mouthguards (0.990,1.750). In this study, there was no advantage of wearing a custom made mouthguard over a boil‐and‐bite mouthguard to reduce the risk of cerebral concussion in football players.
TAF1 Activates Transcription by Phosphorylation of Serine 33 in Histone H2B
Authors: Maile Tobias , Kwoczynski Simona , Katzenberger Rebeccah J. , Wassarman David A. , Sauer Frank
Published: May 2004

Dynamic changes in chromatin structure, induced by posttranslational modification of histones, play a fundamental role in regulating eukaryotic transcription. Here we report that histone H2B is phosphorylated at evolutionarily conserved Ser
33
(H2B-S33) by the carboxyl-terminal kinase domain (CTK) of the
Drosophila
TFIID subunit TAF1. Phosphorylation of H2B-S33 at the promoter of the cell cycle regulatory gene
string
and the segmentation gene
giant
coincides with transcriptional activation. Elimination of TAF1 CTK activity in
Drosophila
cells and embryos reduces transcriptional activation and phosphorylation of H2B-S33. These data reveal that H2B-S33 is a physiological substrate for the TAF1 CTK and that H2B-S33 phosphorylation is essential for transcriptional activation events that promote cell cycle progression and development.
Reduction of Particulate Air Pollution Lowers the Risk of Heritable Mutations in Mice
Authors: Somers Christopher M. , McCarry Brian E. , Malek Farideh , Quinn James S.
Published: May 2004

Urban and industrial air pollution can cause elevated heritable mutation rates in birds and rodents. The relative importance of airborne particulate matter versus gas-phase substances in causing these genetic effects under ambient conditions has been unclear. Here we show that high-efficiency particulate-air (HEPA) filtration of ambient air significantly reduced heritable mutation rates at repetitive DNA loci in laboratory mice housed outdoors near a major highway and two integrated steel mills. These findings implicate exposure to airborne particulate matter as a principal factor contributing to elevated mutation rates in sentinel mice and add to accumulating evidence that air pollution may pose genetic risks to humans and wildlife.
The Wide Spectrum of Sex and Gender
Authors: Jolly Alison
Published: May 2004

Evolution's Rainbow
Diversity, Gender, and Sexuality in Nature and People. by Joan Roughgarden. University of California Press, Berkeley, 2004. 480 pp. $27.50. ISBN 0-520-24073-1.

In this long-anticipated (and already controversial) work, Roughgarden discusses the origins and development of sexual and gender diversity in vertebrates. She argues against Darwinian sexual selection and a range of generally accepted scientific concepts and theories.
Asphalt Volcanism and Chemosynthetic Life in the Campeche Knolls, Gulf of Mexico
Authors: MacDonald I. R. , Bohrmann G. , Escobar E. , Abegg F. , Blanchon P. , Blinova V. , Brückmann W. , Drews M. , Eisenhauer A. , Han X. , Heeschen K. , Meier F. , Mortera C. , Naehr T. , Orcutt B. , Bernard B. , Brooks J. , de Faragó M.
Published: May 2004

In the Campeche Knolls, in the southern Gulf of Mexico, lava-like flows of solidified asphalt cover more than 1 square kilometer of the rim of a dissected salt dome at a depth of 3000 meters below sea level. Chemosynthetic tubeworms and bivalves colonize the sea floor near the asphalt, which chilled and contracted after discharge. The site also includes oil seeps, gas hydrate deposits, locally anoxic sediments, and slabs of authigenic carbonate. Asphalt volcanism creates a habitat for chemosynthetic life that may be widespread at great depth in the Gulf of Mexico.
PROTON NUCLEUS COLLISIONS AND THE COLOR GLASS CONDENSATE
Authors: JALILIAN-MARIAN JAMAL
Published: May 2004

We review the high parton density limit of QCD and show how the Color Glass Condensate arises at small xbj. We discuss the applications of the Color Glass Condensate formalism to proton (deuteron) nucleus collisions at high energy colliders, such as RHIC and LHC.
NEW PARITY-VIOLATING PHOTON–AXION INTERACTION
Authors: MAJUMDAR PARTHASARATHI
Published: May 2004

A variant of an earlier proposal by the author and SenGupta, to describe four-dimensional Maxwell electrodynamics in Einstein–Cartan spacetimes through a Kalb–Ramond field as an intermediary, is shown to lead to a new Maxwell–Kalb–Ramond coupling that violates spatial parity, even when the KR gauge field has its standard parity assignment. One consequence of this coupling seems to be a modulation, independent of wavelength but dependent on the KR field strength, of the intensity of synchrotron radiation observed from distant galactic sources.