bluuebunny/crossref_metadata_2025 huggingface dataset:
Scattering from capped cylinders. Addendum
Authors: Kaya Håkon , de Souza Nicolas-Raphaël
Published: May 2004

In a recent paper [Kaya (2004).J. Appl. Cryst.37, 223–230], the scattering function and the radius of gyration of a cylinder with globular end-caps (a barbell) were presented. It was shown that the model covered several geometries by simply varying three variables. In this addendum, it is pointed out that the model, without any changes, contains the scattering functions of two other distinct shapes, namely a cylinder with small end-caps, which in the no-cylinder limit becomes a lens-shaped disc. The scattering function of a regular cylinder with flat ends (no end-caps) is also included in the model.
Neutron imaging with bent perfect crystals. II. Practical multi-wafer approach
Authors: Stoica A. D. , Popovici M. , Wang X.-L. , Wang D.-Q. , Hubbard C. R.
Published: May 2004

In a previous paper [Stoica, Popovici & Hubbard (2001),J. Appl. Cryst.34, 343–357], the phase-space analysis of neutron imaging by Bragg reflection from thick bent perfect crystals or multi-wafer assemblies resulted in the derivation of various imaging conditions. An array of new applications becomes possible, including dispersive and non-dispersive neutron imaging at a sub-millimetre spatial resolution. This paper outlines the experimental test results on non-dispersive imaging with thick packets of silicon wafers. The experimental results are compared with Monte Carlo simulations.
Intermediate disturbance in a late‐successional hemlock‐northern hardwood forest
Authors: WOODS KERRY D.
Published: May 2004

An old‐growth mesic forest in northern Michigan, USA, experienced an unusually intense storm in July 2002. Permanent inventory plots and a 2.9‐ha mapped stand allow comparison of effects of this rare disturbance with patterns of ‘baseline’ mortality.

Tree mortality attributable to immediate effects of the storm was of similar magnitude to mortality over the previous decade, amounting to about 9% of basal area and 7% of stem density (mean of 88 inventory plots).

Storm mortality differed from baseline mortality in patterns related to species and size. Tsuga canadensis suffered little mortality of either type. Betula alleghaniensis had high baseline mortality in all size classes, but very low storm mortality. Acer spp. and Fagus grandifolia showed similar overall levels of baseline and storm mortality, but storm mortality was higher for larger stems.

Spatial patterns of mortality differed between baseline and storm‐caused disturbance, with storm mortality patterns related to composition and to substrate variation over the stand. Baseline canopy mortality was hyperdispersed at local scales, but mortality due to the storm was strongly clustered at distances up to 30 m.

Properties of rare, intermediate disturbances cannot be predicted by simply scaling up patterns due to frequent, less intense, events. They may have distinctive influences on community dynamics, countering trends towards dominance by shade‐tolerant species, generating demographic and spatial structure in the canopy, and distinctively affecting understorey environment.

These results suggest that climate change may induce changes in forest ecosystems by changing disturbance patterns even when species are not close to limits of physiological tolerance. Forest management for natural regeneration may need to take the effects of rare, intermediate disturbance into account.
Propagule pools mediate community assembly and diversity‐ecosystem regulation along a grassland productivity gradient
Authors: FOSTER BRYAN L. , DICKSON TIMOTHY L. , MURPHY CHERYL A. , KAREL IRENE S. , SMITH VAL H.
Published: May 2004

The relative importance of regional species pools and local ecological processes in governing landscape variation in plant species diversity and productivity was evaluated in a Kansas grassland.

We examined the impact of multispecies sowing treatments and experimental canopy disturbances on plant species diversity and ecosystem processes along a complex natural gradient of plant standing crop.

Data collected 4 years after sowing showed that plant invasion and diversity were seed limited in unproductive sites, but microsite limited in productive sites. Effects of sowing on plant diversity along the natural landscape gradient were paralleled by significant effects of sowing on measures of local plant production and community resilience to disturbance.

These results support the shifting limitations hypothesis (SLH) that landscape gradients in local plant diversity should reflect shifts in the major regulating factor, from species pools to local ecological processes, as one moves from sites of inherently low to inherently high productivity.

Our findings also indicate that diversity at the level of the available propagule pool acts to constrain ecosystem productivity and stability by mediating local community assembly, by determining the availability of key species, and by governing opportunities for functional compensation within the community.

In total, our results support an emerging view that community processes and ecosystem functions are dynamically linked and act reciprocally to constrain each other.
Relative importance of suppression‐based and tolerance‐based competition in an invaded oak savanna
Authors: MacDOUGALL ANDREW S. , TURKINGTON ROY
Published: May 2004

Invasive species dominate many ecosystems but the competitive strategies underlying this dominance are unclear. Are invasive species generalist competitors, or do they only thrive in certain environments? Do they occur mainly post‐disturbance or can they persist throughout succession?

We tested the relative importance of resource acquisition (competitive suppression ability) and the ability to tolerate reduced resource levels (competitive tolerance ability) among four C3 perennial grass species in an invaded oak savanna. Two species (Poa pratensisandDactylis glomerata) are exotic invaders and are thought to have replaced the two native species (Bromus carinatusandElymus glaucus) as dominants.

Using glasshouse and field experiments we tested whether the two strategies were maintained with changing resource levels and successional conditions, and their relative roles in explaining exotic dominance.

The relative importance of suppression‐ and tolerance‐based competition shifted with neighbour density, burning and planting order. Further, the relative importance of particular plant traits changed depending on the imposed conditions, and the exotic dominants were only competitively superior under certain circumstances.

Competitive suppression ability was maintained with changing resource levels but was confined to post‐disturbance conditions. When planting of neighbours was delayed, the early establishing targets were dominant regardless of species, fertility and neighbour density.

Competitive tolerance ability determined long‐term patterns of relative abundance and coexistence, but only under the current field conditions of low fertility and limited disturbance. Alteration of these conditions changed the relative abundance of the four grasses, and would probably reconfigure species patterns in the oak savanna community generally.

Exotic dominance is presently determined by tolerance‐based competitive traits interacting with the long‐term absence of disturbance. Dominance is therefore contingent on the interaction of competitive strategies, resource availability and disturbance history rather than any one factor alone.

Exotic flora dominate all stages of succession in this savanna because there exists both early (suppression) and late (tolerance) successional specialists. The identity of the dominant changes with succession based on the competitive strategy it employs. This result highlights the importance of examining the historical context of invaded communities and tracking their successional status over time.
Induction of two indirect defences benefits Lima bean (Phaseolus lunatus, Fabaceae) in nature
Authors: HEIL MARTIN
Published: May 2004

Herbivore damage often induces the release of herbivore‐induced plant volatiles (HIPVs) or the secretion of extrafloral nectar (EFN). The purpose of this study was to induce such proposed indirect defence responses in plants growing in their natural environment and to monitor the effects on vegetative and generative traits such as herbivory, plant growth and fruit set.

I tested whether mature wild Lima beans (Phaseolus lunatus, Fabaceae) growing in Mexico could be reliably induced to produce HIPVs and EFN in response to application of the phytohormone, jasmonic acid (JA), and investigated whether this treatment leads to any benefit to the plants.

Eleven HIPVs were released from JA‐treated leaves at significantly higher amounts than from control leaves, and only one (methylsalicylate) at significantly lower amounts than from controls. Treatment with JA increased EFN secretion on leaves on average by more than 30 times and on bracts by more than 20 times. EFN production, which has not previously been described in Lima bean, represents a second induced indirect resistance trait of this species.

JA treatment reduced both the number of dead shoot tips and leaf damage by herbivores. Treated tendrils grew faster and produced more leaves than controls. At the end of the experiment, treated tendrils bore c. two times more inflorescences and three times more fruits than controls.

Repeated treatment with JA resulted in a combined induction of HIPVs and EFN and strongly benefited wild Lima beans. The plants suffered less from the consequences of herbivore attack, supporting the use of the term ‘induced defences’ for these traits. JA‐induced defences thus can significantly benefit Lima bean under natural conditions.
Name‐calling and Peer Beliefs among Primary School Children in Turkey
Authors: Yurtal Filiz
Published: May 2004

Name‐calling is a common problem among primary school children in Turkey as in other countries. The Name‐Calling Survey and Peer Beliefs Inventory were used to determine the relationships between name‐calling and peer beliefs amongst a group of 319 primary school children in Turkey. Name‐calling was found to be more common amongst boys than girls. A negative relationship was found between name‐calling and peer beliefs, so that the greater experience of name‐calling, the more children disliked their peers. Gender and grade level were found to have a significant negative relationship. The name‐calling experiences of students affected their friendship relationships negatively, which contributed to violence in schools. School counsellors must be aware of name‐calling victims and perpetrators, as well as organizing educational programmes aimed at helping students to cope with these problems.
CONSEQUENTIALISM, TELEOLOGY, AND THE NEW FRIENDSHIP CRITIQUE1
Authors: CARD ROBERT F.
Published: May 2004

Abstract: A powerful objection to impersonal moral theories states that they cannot accommodate the good of friendship. This paper focuses on the problem as it applies to consequentialism and addresses the recent criticism that even the most sophisticated forms of consequentialism are incompatible with genuine friendship. I argue that this objection fails since those who pose this challenge either seriously oversimplify consequentialism's theory of value, misunderstand its theory of practical reason, or put too much weight on the good of friendship itself. I conclude by assessing a contemporary consequentialist response in order to suggest a workable conception of consequentialist friendship.
RESPONSIBILITY AND THE AIMS OF THEORY: STRAWSON AND REVISIONISM
Authors: VARGAS MANUEL
Published: May 2004

Abstract:  Strawsonian approaches to responsibility, including more recent accounts such as Dennett's and Wallace’s, face a number of important objections. However, Strawsonian theories can be recast along revisionist lines so as to avoid many of these problems. In this paper, I explain the revisionist approach to moral responsibility, discuss the concessions it makes to incompatibilism (including the point that compatibilists may not fully capture what our commonsense understanding of responsibility), why it provides a fruitful recasting of Strawsonian approaches, and how it offers an alternative to the pattern of dialectical stalemates exhibited by standard approaches to free will and determinism.
Variation in wood density determines spatial patterns inAmazonian forest biomass
Authors: Baker Timothy R. , Phillips Oliver L. , Malhi Yadvinder , Almeida Samuel , Arroyo Luzmila , Di Fiore Anthony , Erwin Terry , Killeen Timothy J. , Laurance Susan G. , Laurance William F. , Lewis Simon L. , Lloyd Jon , Monteagudo Abel , Neill David A. , Patiño Sandra , Pitman Nigel C. A. , M. Silva J. Natalino , Vásquez Martínez Rodolfo
Published: May 2004

Uncertainty in biomass estimates is one of the greatest limitations to models of carbon flux in tropical forests. Previous comparisons of field‐based estimates of the aboveground biomass (AGB) of trees greater than 10 cm diameter within Amazonia have been limited by the paucity of data for western Amazon forests, and the use of site‐specific methods to estimate biomass from inventory data. In addition, the role of regional variation in stand‐level wood specific gravity has not previously been considered. Using data from 56 mature forest plots across Amazonia, we consider the relative roles of species composition (wood specific gravity) and forest structure (basal area) in determining variation in AGB.

Mean stand‐level wood specific gravity, on a per stem basis, is 15.8% higher in forests in central and eastern, compared with northwestern Amazonia. This pattern is due to the higher diversity and abundance of taxa with high specific gravity values in central and eastern Amazonia, and the greater diversity and abundance of taxa with low specific gravity values in western Amazonia. For two estimates of AGB derived using different allometric equations, basal area explains 51.7% and 63.4%, and stand‐level specific gravity 45.4% and 29.7%, of the total variation in AGB. The variation in specific gravity is important because it determines the regional scale, spatial pattern of AGB. When weighting by specific gravity is included, central and eastern Amazon forests have significantly higher AGB than stands in northwest or southwest Amazonia. The regional‐scale pattern of species composition therefore defines a broad gradient of AGB across Amazonia.
Biogenic VOC emissions from forested Amazonian landscapes
Authors: Greenberg James P. , Guenther Alex B. , Pétron Gabrielle , Wiedinmyer Christine , Vega Oscar , Gatti Luciana V. , Tota Julio , Fisch Gilberto
Published: May 2004

A tethered balloon‐sampling platform was used to study biogenic volatile organic compounds (BVOCs) in the atmospheric boundary layer in three distinct moist tropical forest ecoregions, as well as an extensive pasture area, in Amazonia. Approximately 24–40 soundings, including as many as four VOC samples collected simultaneously at various altitudes, were made at each site. Concentrations in the mixed layer increased during morning hours and were relatively constant midday through afternoon. Since most important meteorological and chemical parameters were very similar among the sites during the measurement periods, a BVOC canopy emission model was used with a model of the chemistry of the boundary layer to reproduce the atmospheric concentrations observed. The simulations indicated significantly different midday landscape isoprene and α‐pinene emission rates for the three forest ecoregions (2200, 5300, 9800 μg m−2 h−1 isoprene and 90, 120, and 180 μg m−2 h−1α‐pinene for the three moist forest ecoregions studied, respectively). The differences in emissions among the ecoregions may be attributed to the species composition, which were markedly different and in which the percentage of isoprene and terpene emitting species also differed significantly.
Modeling changes in soil organic matter in Amazon forest to pasture conversion with the Century model
Authors: Cerri Carlos Eduardo P. , Paustian Keith , Bernoux Martial , Victoria Reynaldo L. , Melillo Jerry M. , Cerri Carlos C.
Published: May 2004

Land use and land cover changes in the Brazilian Amazon region have major implications for regional and even global carbon cycling. We analyzed the effects of the predominant land use change, conversion of tropical forest to pasture, on total soil C and N, using the Century ecosystem model and data collected from the Nova Vida ranch, Western Brazilian Amazon. We estimated equilibrium organic matter levels, plant productivity and residue carbon inputs under native forest conditions, then simulated deforestation following the slash and burn procedure. Soil organic matter dynamics were simulated for pastures established in 1989, 1987, 1983, 1979, 1972, 1951, and 1911. Using input data from the Nova Vida ranch, the Century model predicted that forest clearance and conversion to pasture would cause an initial decline in soil C and N stocks, followed by a slow rise to levels exceeding those under native forest. Simulated soil total C and N levels (2500 g C m−2 and 245 g N m−2 in the 0–20 cm layer) prior to conversion to pasture were close to those measured in the native forest. Simulated above‐ and below‐ground biomass for the forest and pasture were comparable with literature values from this region. The model predicted the long‐term changes in soil C and N under pasture inferred from the pasture chronosequence, but there was considerable variation in soil C stocks for pastures <20 years in age. Differences in soil texture between pastures were relatively small and could not account for much of the variability between different pastures of similar ages, in either the measured or simulated data. It is likely that much of the variability in C stocks between pastures of similar ages is related to initial C stocks immediately following deforestation and that this was the largest source of variability in the chronosequence. Internal C cycling processes in Century were evaluated using measurements of microbial biomass and soil δ13C. The relative magnitude and long‐term trend in microbial biomass simulated by the model were consistent with measurements. The close fit of simulated to measured values of δ13C over time suggests that the relative loss of forest‐derived C and its replacement by pasture‐derived C was accurately predicted by the model. After 80 years, almost 90% of the organic matter in the top 20 cm was pasture derived. While our analysis represents a single ‘case study’ of pasture conversion, our results suggest that modeling studies in these pasture systems can help to evaluate the magnitude of impacts on C and N cycling, and determine the effect of management strategies on pasture sustainability.
How was it for you? Families’ experiences of receiving Behavioural Family Therapy
Authors: CAMPBELL A. S.
Published: May 2004

The benefits of family interventions for families having to cope with serious mental health problems are well documented but routine implementation of these interventions is often problematic. Despite a wealth of research on the clinical outcomes of such interventions, very little is known about families’ subjective perceptions of receiving them. This study reports the findings of a phenomenological enquiry into the lived experience of 10 families who received Behavioural Family Therapy (BFT) as part of a training initiative in the West Midlands Health Region of the UK. The results show that families were very satisfied with the intervention. They reported reductions in the levels of stress within the family, reduction in levels of carer burden, enhanced communication skills and a positive sense of empowerment. They attributed these changes to receiving BFT. The majority of families viewed mental health professionals and services more favourably compared to their experiences before receiving BFT. This is an important finding for service providers, commissioners and mental heath workers.
The user perspective: respected or rejected in mental health care?
Authors: HANSEN T. , HATLING T. , LIDAL E. , RUUD T.
Published: May 2004

The purpose of this study was to examine the extent to which patient views influence treatment planning by measuring the level of agreement between patients and health workers regarding patient needs as well as the impact of patient wishes on decision making when viewpoints conflict. Data on patient characteristics and needs were collected for a sample of 1080 patients within Norwegian mental health care using patient interviews and health worker ratings. Results of the assessment were then reviewed by multidisciplinary treatment teams responsible for making decisions regarding patient needs for services. On average, patients, health workers, and teams identified 4.3 (SD = 4.2), 9.3 (SD = 5.5), and 10.3 (SD = 5.7), respectively, of 40 possible needs per patient. In cases where patient and health workers disagreed on the presence of a need, the teams tended to concur with the health worker. Interestingly, health care workers and teams were far more inclined than their patients to identify needs related to professional monitoring and follow‐up. Results may indicate that contemporary tenets in mental health care regarding user involvement and autonomy are not sufficiently emphasized in practice.
Mental health service user involvement in England: lessons from history
Authors: RUSH B.
Published: May 2004

This historical analysis draws attention to differing assumptions, which promote or limit user involvement in nursing practice. The meaning of the term ‘user involvement’ is analyzed with reference to varying models. A continuum is offered to illustrate the relationship between assumptions about people with mental health problems and their involvement in care. It is argued that the range of views concerning recipients of mental health services, from being dangerous and irrational to being considered equal partners with health professionals, creates an unresolved tension that has existed through the ages. The key to resolving this tension is for all parties openly to acknowledge conflicts between their views and those of others and engage in meaningful dialogue about them. In this way the lessons from history may be learned.
Teleconnection between tree growth in the Amazonian floodplains and the El Niño–Southern Oscillation effect
Authors: Schöngart Jochen , Junk Wolfgang J. , Piedade Maria Teresa F. , Ayres José Marcio , Hüttermann Aloys , Worbes Martin
Published: May 2004

There is a limited knowledge about the El Niño–Southern Oscillation (ENSO) effects on the Amazon basin, the world's largest tropical rain forest and a major factor in the global carbon cycle. Seasonal precipitation in the Andean watershed annually causes a several month‐long inundation of the floodplains along the Amazon River that induces the formation of annual rings in trees of the flooded forests. Radial growth of trees is mainly restricted to the nonflooded period and thus the ring width corresponds to its duration. This allows the construction of a tree‐ring chronology of the long‐living hardwood species Piranhea trifoliata Baill. (Euphorbiaceae). El Niño causes anomalously low precipitation in the catchment that results in a significantly lower water discharge of the Amazon River and consequently in an extension of the vegetation period. In those years tree rings are significantly wider. Thus the tree‐ring record can be considered as a robust indicator reflecting the mean climate conditions of the whole Western Amazon basin. We present a more than 200‐year long chronology, which is the first ENSO‐sensitive dendroclimatic proxy of the Amazon basin and permits the dating of preinstrumental El Niño events. Time series analyses of our data indicate that during the last two centuries the severity of El Niño increased significantly.
Simulating the response of land‐cover changes to road paving and governance along a major Amazon highway: the Santarém–Cuiabá corridor
Authors: Soares‐Filho Britaldo , Alencar Ane , Nepstad Daniel , Cerqueira Gustavo , Vera Diaz Maria del Carmen , Rivero Sérgio , Solórzano Luis , Voll Eliane
Published: May 2004

The spatial distribution of human activities in forest frontier regions is strongly influenced by transportation infrastructure. With the planned paving of 6000 km of highway in the Amazon Basin, agricultural frontier expansion will follow, triggering potentially large changes in the location and rate of deforestation. We developed a land‐cover change simulation model that is responsive to road paving and policy intervention scenarios for the BR‐163 highway in central Amazonia. This corridor links the cities of Cuiabá, in central Brazil, and Santarém, on the southern margin of the Amazon River. It connects important soybean production regions and burgeoning population centers in Mato Grosso State with the international port of Santarém, but 1000 km of this road are still not paved. It is within this context that the Brazilian government has prioritized the paving of this road to turn it into a major soybean exportation facility. The model assesses the impacts of this road paving within four scenarios: two population scenarios (high and moderate growth) and two policy intervention scenarios. In the ‘business‐as‐usual’ policy scenario, the responses of deforestation and land abandonment to road paving are estimated based on historical rates of Amazon regions that had a major road paved. In the ‘governance’ scenario, several plausible improvements in the enforcement of environmental regulations, support for sustainable land‐use systems, and local institutional capacity are invoked to modify the historical rates. Model inputs include data collected during expeditions and through participatory mapping exercises conducted with agents from four major frontier types along the road. The model has two components. A scenario‐generating submodel is coupled to a landscape dynamics simulator, ‘DINAMICA’, which spatially allocates the land‐cover transitions using a GIS database. The model was run for 30 years, divided into annual time steps. It predicted more than twice as much deforestation along the corridor in business‐as‐usual vs. governance scenarios. The model demonstrates how field data gathered along a 1000 km corridor can be used to develop plausible scenarios of future land‐cover change trajectories that are relevant to both global change science and the decision‐making process of governments and civil society in an important rainforest region.
High rates of net ecosystem carbon assimilation by Brachiara pasture in the Brazilian Cerrado
Authors: Santos Alexandre J.B. , Quesada Carlos A. , Da Silva Gabriela T. , Maia Jair F. , Miranda Heloisa S. , Carlos Miranda Antonio , Lloyd Jon
Published: May 2004

To investigate the consequences of land use on carbon and energy exchanges between the ecosystem and atmosphere, we measured CO2 and water vapour fluxes over an introduced Brachiara brizantha pasture located in the Cerrado region of Central Brazil. Measurements using eddy covariance technique were carried out in field campaigns during the wet and dry seasons. Midday CO2 net ecosystem exchange rates during the wet season were −40 μmol m−2 s−1, which is more than twice the rate found in the dry season (−15 μmol m−2 s−1). This was observed despite similar magnitudes of irradiance, air and soil temperatures. During the wet season, inferred rates of canopy photosynthesis did not show any tendency to saturate at high solar radiation levels, with rates of around 50 μmol m−2 s−1 being observed at the maximum incoming photon flux densities of 2200 μmol m−2 s−1. This contrasted strongly to the dry period when light saturation occurred with 1500 μmol m−2 s−1 and with maximum canopy photosynthetic rates of only 20 μmol m−2 s−1. Both canopy photosynthetic rates and night‐time ecosystem CO2 efflux rates were much greater than has been observed for cerrado native vegetation in both the wet and dry seasons. Indeed, observed CO2 exchange rates were also much greater than has previously been reported for C4 pastures in the tropics. The high rates in the wet season may have been attributable, at least in part, to the pasture not being grazed. Higher than expected net rates of carbon acquisition during the dry season may also have been attributable to some early rain events. Nevertheless, the present study demonstrates that well‐managed, productive tropical pastures can attain ecosystem gas exchange rates equivalent to fertilized C4 crops growing in the temperate zone.
The above‐ground coarse wood productivity of 104 Neotropical forest plots
Authors: Malhi Yadvinder , Baker Timothy R. , Phillips Oliver L. , Almeida Samuel , Alvarez Esteban , Arroyo Luzmilla , Chave Jerome , Czimczik Claudia I. , Fiore Anthony Di , Higuchi Niro , Killeen Timothy J. , Laurance Susan G. , Laurance William F. , Lewis Simon L. , Montoya Lina María Mercado , Monteagudo Abel , Neill David A. , Vargas Percy Núñez , Patiño Sandra , Pitman Nigel C.A. , Quesada Carlos Alberto , Salomão Rafael , Silva José Natalino Macedo , Lezama Armando Torres , Martínez Rodolfo Vásquez , Terborgh John , Vinceti Barbara , Lloyd Jon
Published: May 2004

The net primary production of tropical forests and its partitioning between long‐lived carbon pools (wood) and shorter‐lived pools (leaves, fine roots) are of considerable importance in the global carbon cycle. However, these terms have only been studied at a handful of field sites, and with no consistent calculation methodology. Here we calculate above‐ground coarse wood carbon productivity for 104 forest plots in lowland New World humid tropical forests, using a consistent calculation methodology that incorporates corrections for spatial variations in tree‐size distributions and wood density, and for census interval length. Mean wood density is found to be lower in more productive forests. We estimate that above‐ground coarse wood productivity varies by more than a factor of three (between 1.5 and 5.5 Mg C ha−1 a−1) across the Neotropical plots, with a mean value of 3.1 Mg C ha−1 a−1. There appear to be no obvious relationships between wood productivity and rainfall, dry season length or sunshine, but there is some hint of increased productivity at lower temperatures. There is, however, also strong evidence for a positive relationship between wood productivity and soil fertility. Fertile soils tend to become more common towards the Andes and at slightly higher than average elevations, so the apparent temperature/productivity relationship is probably not a direct one. Coarse wood productivity accounts for only a fraction of overall tropical forest net primary productivity, but the available data indicate that it is approximately proportional to total above‐ground productivity. We speculate that the large variation in wood productivity is unlikely to directly imply an equivalent variation in gross primary production. Instead a shifting balance in carbon allocation between respiration, wood carbon and fine root production seems the more likely explanation.
Fracture resistance of re‐attached coronal fragments – influence of different adhesive materials and bevel preparation
Authors: Demarco Flávio Fernando , Fay Rose‐Marie , Pinzon Lilliam Marie , Powers John M.
Published: May 2004

Abstract  – The purpose of this study was to investigate the fracture resistance of re‐attached coronal fragments of teeth using different materials and tooth preparations. Seventy‐two recently extracted bovine incisors were selected. Eight incisors were maintained without any preparation as a control group. The incisal third of the other teeth was sectioned using a diamond saw. In one group (n = 32), a 2‐mm bevel was prepared, whereas in the second group no preparation was made (n = 32). The specimens (beveled and non‐beveled) were divided in four groups (n = 8) and re‐attached with the following materials: a dual‐cured resin cement RelyX ARC (RX); a chemically cured composite Bisfil 2B (B2); a light‐cured composite Z250 (Z2); and a one‐bottle adhesive Single Bond (SB). The bevel region was restored with adhesive and composite. All materials were used according to manufacturer's directions. A light‐curing unit was used to polymerize the materials. Specimens were stored in saline solution for 72 h. De‐bonding procedures were performed in a testing machine with cross‐head speed of 0.6 mm min−1. The load was applied in the incisal third. The resistance to fracture for control group was 70 (7) kg. The fracture resistance for non‐beveled and beveled specimens were: SB, 3.3 (2.4) and 17.0 (4.1); RX, 11.5 (3.0) and 16.3 (3.1); Z2, 14.4 (4.2) and 20.5 (1.7); and B2, 19.5 (3.5) and 32.5 (7.4) kg. Analysis of variance (anova) and Fisher's protected least significant difference (PLSD) test disclosed significant influence for materials and cavity designs (P = 0.001). The highest failure loads were obtained with the B2 group and then with the Z2 with either bevel or non‐bevel. RX produced lower failure loads than the restorative composites. The lowest failure load was obtained with SB in the non‐beveled group. No technique studied was able to attain the fracture resistance of the control group and both materials and tooth preparation influenced the fracture resistance.
Influence of the type of dental trauma on the pulp vitality and the time elapsed until treatment: a study in patients aged 0–3 years
Authors: Pugliesi Daniela Maria Carvalho , Cunha Robson Frederico , Delbem Alberto Carlos Botazzo , Sundefeld Maria Lúcia Marçal Mazza
Published: May 2004

Abstract  – The purpose of the present study was to determine the influence of the type of trauma on the pulp vitality and the time elapsed until seeking dental care in children aged 0–3 years seen at the Baby Clinic of the Araçatuba Dental School, UNESP. A total of 1813 records were analyzed. Two hundred and three patients, corresponding to 302 traumatized teeth, were assessed clinically and radiographically. Hard‐tissue injuries were the most frequent (52%), with a predominance of enamel crown fractures (41.4%), followed by concussions (12.6%) and intrusions (11.6%). Clinical and radiographic examination revealed that 72% of the traumatized teeth maintained pulp vitality. In the case of supporting‐tissue lesions, 51.1% of the patients sought care within 1–15 days after injury, while in the case of hard‐tissue injuries, 52.7% sought care only after 16 days. The results showed that supporting‐tissue injuries had a significant influence on the faster seeking of dental care.
Exclusive Consolidated Memory Phases in
Drosophila
Authors: Isabel Guillaume , Pascual Alberto , Preat Thomas
Published: May 2004

Two types of consolidated memory have been described in
Drosophila
, anesthesia-resistant memory (ARM), a shorter-lived form, and stabilized long-term memory (LTM). Until now, it has been thought that ARM and LTM coexist. On the contrary, we show that LTM formation leads to the extinction of ARM. Flies devoid of mushroom body vertical lobes cannot form LTM, but spaced conditioning can still erase their ARM, resulting in a remarkable situation: The more these flies are trained, the less they remember. We propose that ARM acts as a gating mechanism that ensures that LTM is formed only after repetitive and spaced training.
Mutual Benefits at All Levels of Life
Authors: Trivers Robert
Published: May 2004

Genetic and Cultural Evolution of Cooperation
. Peter Hammerstein, Ed. MIT Press, Cambridge, MA, 2003. 499 pp. $45, £29.95. ISBN 0-262-08326-4.

In this volume, which grew out of a Dahlem Workshop, researchers from a wide range of fields--including biology, anthropology, economics, mathematics, political science, primatology, and psychology--discuss the origins, evolution, and cultural mechanisms of cooperation.
Regulation of Phagosome Maturation by Signals from Toll-Like Receptors
Authors: Blander J. Magarian , Medzhitov Ruslan
Published: May 2004

In higher metazoans, phagocytosis is essential in host defense against microbial pathogens and in clearance of apoptotic cells. Both microbial and apoptotic cells are delivered on a common route from phagosomes to lysosomes for degradation. Here, we found that activation of the Toll-like receptor (TLR) signaling pathway by bacteria, but not apoptotic cells, regulated phagocytosis at multiple steps including internalization and phagosome maturation. Phagocytosis of bacteria was impaired in the absence of TLR signaling. Two modes of phagosome maturation were observed, constitutive and inducible; their differential engagement depended on the ability of the cargo to trigger TLR signaling.
Epidemic soybean asthma and public health: new control systems and initial evaluation in Barcelona, 1996–98
Authors: Villalbí J R , Plasencia A , Manzanera R , Armengol R , Antó J M
Published: May 2004

Objective:To evaluate the new measures adopted to control the risks from soybean unloading operations in the Port of Barcelona, after an episode of epidemic asthma in June 1996.

Methods:After an initial cautionary suspension of all soybean unloading operations, they were subsequently resumed under restrictive criteria for time, flux, simultaneity, and meteorological conditions. Emission filtration systems based on either micro pore size filters or polytetrafluoroethylene membranes on tetratex filters showed promising results.

Results:Allergen emission underwent a very important decrease to levels 95% to 98% lower. Emissions from the two plants with unloading operations are in the same order of magnitude as the processing plant that does not unload soybean. Allergen concentration levels presented fluctuations initially, but the new filters decreased mean values; despite increased unloading, allergen levels did not increase—mean allergen levels on unloading days (67 U/m3) and on days without unloading operations (63 U/m3) are similar. A panel of patients detected a cluster of increased symptoms during unloading operations on a day with suboptimal meteorological conditions and comparatively low allergen levels (225–415 U/m3). Since the June 1996 episode, no further asthma outbreak has been detected.

Conclusions:The evaluation shows the effectiveness of the new filters in the control of soybean dust emission. With a systematic control programme, industrial soybean operations may function near urban centres without public health risks. These data may be useful in the development of future standards for allergenic agents.
Involvement in civil society groups: Is it good for your health?
Authors: Ziersch A M , Baum F E
Published: May 2004

Study objective:To determine the involvement in civil society groups (CSGs) and the impact of this on health.

Design:Case study, cross sectional, self completion questionnaire, and semi-structured interviews.

Setting:Residents in two suburbs in Adelaide, South Australia.

Participants:Every household (1038) received a questionnaire asking the adult with the next birthday to complete it. A total of 530 questionnaires were returned. Sixteen questionnaire respondents were also interviewed.

Main results:279 (53%) questionnaire respondents had been involved in a CSG in the past 12 months, 190 (36%) in locally based CSGs, and 188 (35%) in CSGs outside the area. Eleven of the 16 interviewees had been involved in a CSG. A path analysis examined the relation between demographic variables, CSG involvement, and mental and physical health, as measured by the SF-12. Physical health was negatively associated with CSG involvement and older age, and positively associated with working full time or part time and higher education level. Mental health was positively associated with older age, working full time or part time, and higher income but negatively associated with having a child under 18, speaking a language other than English and higher education level. Very few interviewees made a direct link between CSGs and positive individual health outcomes, though some positive community level outcomes were noted. More consistent were reports of the detrimental effects of CSG involvement on mental and physical health.

Conclusions:Involvement in CSGs was significant but not always positive for health. It is possible that CSG involvement is good for a community but not necessarily for the individual.
Employment status, employment conditions, and limiting illness: prospective evidence from the British household panel survey 1991–2001
Authors: Bartley M , Sacker A , Clarke P
Published: May 2004

Objectives:To assess the relation of the incidence of, and recovery from, limiting illness to employment status, occupational social class, and income over time in an initially healthy sample of working age men and women.

Methods:Cox proportional hazards models.

Results:There were large differences in the risk of limiting illness according to occupational social class, with men and women in the least favourable employment conditions nearly four times more likely to become ill than those in the most favourable. Unemployment and economic inactivity also had a powerful effect on illness incidence. Limiting illness was not a permanent state for most participants in the study. Employment status was also related to recovery.

Conclusions:Having secure employment in favourable working conditions greatly reduces the risk of healthy people developing limiting illness. Secure employment increases the likelihood of recovery. These findings have considerable implications for both health inequality and economic policies.
TOPOLOGICAL CHARGE OF ADHM INSTANTON ON ${\bf R}^2_{\rm NC}\times{\bf R}^2$
Authors: TIAN YU
Published: May 2004

We have calculated the topological charge of U (N) instantons on nondegenerate noncommutative spacetime to be exactly the instanton number k in a previous paper.1 This paper, which deals with the degenerate [Formula: see text] case, is the continuation of Ref. 1. We find that the same conclusion holds in this case, thus complete the answer to the problem of topological charge of noncommutative U (N) instantons.
QUANTUM EFFECTS AND STABILITY OF CHAMELEON COSMOLOGY
Authors: NOJIRI SHIN'ICHI , ODINTSOV SERGEI D.
Published: May 2004

One possibility to explain the current accelerated expansion of the universe may be related with the presence of cosmologically evolving scalar whose mass depends on the local matter density (chameleon cosmology). We point out that matter quantum effects in such scalar–tensor theory produce the chameleon scalar field dependent conformal anomaly. Such conformal anomaly adds higher derivative terms to chameleon field equation of motion. As a result, the principal possibility for instabilities appears. These instabilities seem to be irrelevant at small curvature but may become dangerous in the regions where gravitational field is strong.
EXOTIC FERMIONS AND BOSONS IN THE QUARTIFICATION MODEL
Authors: CHEN SHAO-LONG , MA ERNEST
Published: May 2004

Exotic fermions of half-integral charges at the TeV energy scale are predicted by the quartification model of Babu, Ma and Willenbrock. We add to these one copy of their scalar analogs and discuss the ensuing phenomenological implications, i.e. radiative contributions to lepton masses and flavor-changing leptonic decays.
INHOMOGENEOUS de SITTER SOLUTION WITH SCALAR FIELD AND PERTURBATIONS SPECTRUM
Authors: IMPONENTE GIOVANNI , MONTANI GIOVANNI
Published: May 2004

We provide an inhomogeneous solution concerning the dynamics of a real self-interacting scalar field minimally coupled to gravity in a region of the configuration space where it performs a slow rolling on a plateau of its potential. During the inhomogeneous de Sitter phase the scalar field dominant term is a function of the spatial coordinates only. This solution is near to the FLRW model allows a classical origin for the inhomogeneous perturbations spectrum.
DYNAMICAL INSTABILITY IN THE FEW-PARTICLE LENNARD–JONES CHAIN
Authors: OKABE TSUNEYASU , YAMADA HIROAKI
Published: May 2004

We show the energy-dependence of maximal Lyapunov exponent in the one-dimensional Lennard–Jones system consisting of three or four particles with a periodic boundary condition. The robustness of the plateau region, in which the energy-dependence is insensitive, is shown for few-particle systems. It is also shown that the plateau region is roughly characterized by the collision property of the particles. Moreover, the Poincare section corresponding to the energy dependence is given.
THE DYNAMICS AND STATISTICS OF BIVARIATE CHAOTIC MAPS IN COMMUNICATIONS MODELING
Authors: HILLIAM RACHEL M. , LAWRANCE ANTHONY J.
Published: May 2004

Statistical and dynamical properties of bivariate (two-dimensional) maps are less understood than their univariate counterparts. This paper gives a synthesis of extended results with exemplifications by bivariate logistic maps, the bivariate Arnold cat map and a bivariate Chebyshev map. The use of synchronization from bivariate maps in communication modeling is exemplified by an embryonic chaos shift keying system.
UNKNOWN INPUT OBSERVERS FOR MESSAGE-EMBEDDED CHAOS SYNCHRONIZATION OF DISCRETE-TIME SYSTEMS
Authors: MILLERIOUX GILLES , DAAFOUZ JAMAL
Published: May 2004

This paper is concerned with chaos synchronization of discrete-time systems for communication purposes. The information to be masked is embedded in the chaotic dynamics of the transmitter and acts as an external input. It cannot be transmitted to the receiver for the sake of security. Hence, the receiver system must be designed such that the information can be unmasked, given the only available output data consisting of a function of the state vector. This problem is solved with an Unknown Input Observers based approach which achieves an Input Independent Global Synchronization. The conditions of existence of such kind of observers along with the systematic procedure to design the gains of the observers are based on the notion of polyquadratic stability and expressed in terms of Linear Matrix Inequalities.
RESONANCE CONTROL FOR A FORCED SINGLE-DEGREE-OF-FREEDOM NONLINEAR SYSTEM
Authors: LEUNG ANDREW Y. T. , JI JIN CHEN , CHEN GUANRONG
Published: May 2004

The main characteristic of a forced single-degree-of-freedom weakly nonlinear system is determined by its primary, super- and sub-harmonic resonances. A nonlinear parametric feedback control is proposed to modify the steady-state resonance responses, thus to reduce the amplitude of the response and to eliminate the saddle-node bifurcations that take place in the resonance responses. The nonlinear gain of the feedback control is determined by analyzing the bifurcation diagrams associated with the corresponding frequency-response equation, from the singularity theory approach. It is shown by illustrative examples that the proposed nonlinear feedback is effective for controlling three kinds of resonance responses.
GLOBAL SYNCHRONIZATION OF A CLASS OF CHAOTIC SYSTEMS WITH A SCALAR TRANSMITTED SIGNAL
Authors: LU JUNGUO , XI YUGENG , WANG XIAOFAN
Published: May 2004

This letter proposes a new global synchronization theorem for a class of chaotic systems. Specially, in the synchronization theorem neither the linear part nor the nonlinear part of the chaotic system requires the special structure indicated in [Wang & Wang, 1998]. We take a linear combination of the original system state variables as the scale-driving signal. We prove that the global synchronization can be attained through the simple linear output error feedback. The linear output error feedback gain is a function of a free parameter. We use Chua's chaotic oscillator and Saito's hyperchaotic system to illustrate the applicability of our synchronization scheme and discuss the issues concerning robustness.