The Mekong's future flows under multiple drivers: How climate change, hydropower developments and irrigation expansions drive hydrological changes

The river flow regime and water resources are highly important for economic growths, flood security, and ecosystem dynamics in the Mekong basin - an important transboundary river basin in South East Asia. The river flow, although remains relatively unregulated, is expected to be increasingly perturbed by climate change and rapidly accelerating socioeconomic developments. Current understanding about hydrological changes under the combined impacts of these drivers, however, remains limited. This study presents projected hydrological changes caused by multiple drivers, namely climate change, large-scale hydropower developments, and irrigated land expansions by 2050s. We found that the future flow regime is highly susceptible to all considered drivers, shown by substantial changes in both annual and seasonal flow distribution. While hydropower developments exhibit limited impacts on annual total flows, climate change and irrigation expansions cause changes of +15% and -3% in annual flows, respectively. However, hydropower developments show the largest seasonal impacts characterized by higher dry season flows (up to +70%) and lower wet season flows (-15%). These strong seasonal impacts tend to outplay those of the other drivers, resulting in the overall hydrological change pattern of strong increases of the dry season flow (up to +160%); flow reduction in the first half of the wet season (up to -25%); and slight flow increase in the second half of the wet season (up to 40%). Furthermore, the cumulative impacts of all drivers cause substantial flow reductions during the early wet season (up to -25% in July), posing challenges for crop production and saltwater intrusion in the downstream Mekong Delta. Substantial flow changes and their consequences require careful considerations of future development activities, as well as timely adaptation to future changes.

Managing flood risks in the Mekong Delta: How to address emerging challenges under climate change and socioeconomic developments

Climate change and accelerating socioeconomic developments increasingly challenge flood-risk management in the Vietnamese Mekong River Delta-a typical large, economically dynamic and highly vulnerable delta. This study identifies and addresses the emerging challenges for flood-risk management. Furthermore, we identify and analyse response solutions, focusing on meaningful configurations of the individual solutions and how they can be tailored to specific challenges using expert surveys, content analysis techniques and statistical inferences. Our findings show that the challenges for flood-risk management are diverse, but critical challenges predominantly arise from the current governance and institutional settings. The top-three challenges include weak collaboration, conflicting management objectives and low responsiveness to new issues. We identified 114 reported solutions and developed six flood management strategies that are tailored to specific challenges. We conclude that the current technology-centric flood management approach is insufficient given the rapid socioecological changes. This approach therefore should be adapted towards a more balanced management configuration where technical and infrastructural measures are combined with institutional and governance resolutions. Insights from this study contribute to the emerging repertoire of contemporary flood management solutions, especially through their configurations and tailoring to specific challenges.

Data for developing allometric models and evaluating carbon stocks of the Zambezi Teak Forests in Zambia

This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The data was generated from the Sesheke, Namwala, and Kabompo sites in Zambia. Though above-ground data was generated for all these three sites, we uprooted trees to determine below-ground biomass from the Sesheke site only. The vegetation was assessed in all three sites. The data includes tree diameter at breast height (DBH), total tree height, wood density, wood dry weight and root dry weight for large (≥ 5 cm DBH) and small (< 5 cm DBH) trees. We further presented Root-to-Shoot Ratios of uprooted trees. Data on the importance-value indices of various species for large and small trees are also determined. Below and above-ground carbon stocks of the surveyed tree species are presented per site. This data were used by Ngoma et al. (2018) [1] to develop above and below-ground biomass models and the reader is referred to this study for additional information, interpretation, and reflection on applying this data.

Thermal comfort in urban green spaces: a survey on a Dutch university campus

To better understand the influence of urban green infrastructure (UGI) on outdoor human thermal comfort, a survey and physical measurements were performed at the campus of the University of Groningen, The Netherlands, in spring and summer 2015. Three hundred eighty-nine respondents were interviewed in five different green spaces. We aimed to analyze people's thermal comfort perception and preference in outdoor urban green spaces, and to specify the combined effects between the thermal environmental and personal factors. The results imply that non-physical environmental and subjective factors (e.g., natural view, quiet environment, and emotional background) were more important in perceiving comfort than the actual thermal conditions. By applying a linear regression and probit analysis, the comfort temperature was found to be 22.2 °C and the preferred temperature was at a surprisingly high 35.7 °C. This can be explained by the observation that most respondents, who live in temperate regions, have a natural tendency to describe their preferred state as "warmer" even when feeling "warm" already. Using the Kruskal-Wallis H test, the four significant factors influencing thermal comfort were people's exposure time in green spaces, previous thermal environment and activity, and their thermal history. However, the effect of thermal history needs further investigation due to the unequal sample sizes of respondents from different climate regions. By providing evidence for the role of the objective and subjective factors on human thermal comfort, the relationship between UGI, microclimate, and thermal comfort can assist urban planning to make better use of green spaces for microclimate regulation.

An Integrated Coral Reef Ecosystem Model to Support Resource Management under a Changing Climate

Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) biomass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers, generally meaning that declines in ecosystem metrics are not as steep as the sum of individual effects of the drivers. These analyses offer one way to quantify impacts and interactions of particular stressors in an ecosystem context and so provide guidance to managers. For example, the model showed that improving water quality, rather than prohibiting fishing, extended the timescales over which corals can maintain high abundance by at least 5–8 years. This result, in turn, provides more scope for corals to adapt or for resilient species to become established and for local and global management efforts to reduce or reverse stressors.

Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season

This study analyzed how the variations of plant area index (PAI) and weather conditions alter the influence of urban green infrastructure (UGI) on microclimate. To observe how diverse UGIs affect the ambient microclimate through the seasons, microclimatic data were measured during the growing season at five sites in a local urban area in The Netherlands. Site A was located in an open space; sites B, C, and D were covered by different types and configurations of green infrastructure (grove, a single deciduous tree, and street trees, respectively); and site E was adjacent to buildings to study the effects of their façades on microclimate. Hemispherical photography and globe thermometers were used to quantify PAI and thermal comfort at both shaded and unshaded locations. The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions. Monthly variations in the differences of mean radiant temperature (∆Tmrt) between shaded and unshaded areas followed the same pattern as the PAI. Linear regression showed a significant positive correlation between PAI and ∆Tmrt. The difference of daily average air temperature (∆T a ) between shaded and unshaded areas was also positively correlated to PAI, but with a slope coefficient below the measurement accuracy (±0.5 °C). This study showed that weather conditions can significantly impact the effectiveness of UGI in regulating microclimate. The results of this study can support the development of appropriate UGI measures to enhance thermal comfort in urban areas.

Exploring the climate change concerns of striped catfish producers in the Mekong Delta, Vietnam

This study investigated the perceptions on and adaptations to climate change impacts of 235 pangasius farmers in the Mekong Delta, Vietnam. Data were collected using semi-structured household surveys in six provinces, from three regions along the Mekong river branches. A Chi-Square test was used to determine the association between variables, and a logit regression model was employed to identify factors correlated with farmer’s perception and adaptation. Less than half of respondents were concerned about climate change and sought suitable adaptation measures to alleviate its impacts. Improving information on climate change and introducing early warning systems could improve the adaptive capacity of pangasius farmers, in particularly for those farmers, who were not concerned yet. Farmers relied strongly on technical support from government agencies, but farmers in the coastal provinces did not express the need for training by these institutions. This contrasting result requires further assessment of the effectiveness of adaptation measures such as breeding salinity tolerant pangasius.

Simulated impacts of climate change on current farming locations of striped catfish (Pangasianodon hypophthalmus; Sauvage) in the Mekong Delta, Vietnam

In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta's economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang's coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish.

The determination of an optimal waste management scenario for Kampala, Uganda

The quality of the environment in the city of Kampala is deteriorating. The city needs a novel waste management approach to improve the environmental quality in its heterogeneous settlement patterns. Earlier, an integrated urban waste flow model (IUWFM) was applied to project the future waste flows and their impacts on the environment of Kampala using four waste management scenarios. These scenarios were 'business-as-usual', 'more enforcement', 'more collection' and 'proper management'. The robustness of the scenario results was determined by using a multi-criteria decision analysis. Twenty-four criteria were identified and grouped as environmental, economic, social, technological and general. Equal weights were assigned to these five sets of criteria. The four scenarios were evaluated against all criteria, and a sensitivity analysis was performed on the role of the equal weights on the choice of the scenarios. The results showed that 'proper management' scenario, which integrates diverse technologies and management programs matching with the local context, is the optimal approach to improve Kampala's environmental quality. Scenarios that emphasized more waste collection, but less resource recovery were ranked in the middle. The scenario of maintaining the status quo performed worst. Application of a mix of diverse technologies and management programs matching the local conditions is the most optimal solution to improve Kampala's environmental quality.

A multi-scale modelling approach for analysing landscape service dynamics

Shifting societal needs drive and shape landscapes and the provision of their services. This paper presents a modelling approach to visualize the regional spatial and temporal dynamics in landscape service supply as a function of changing landscapes and societal demand. This changing demand can result from different policy targets. In this paper we conceptualise the system in which these dynamics take place by explicitly addressing (i) the multifunctional character of a landscape, (ii) the different spatial levels at which interactions between landscape service supply, demand, and land management occur, and (iii) trade-offs in service supply as a result of land management actions. Next, we translate the resulting conceptual framework into an operational model. As a demonstration, this model is applied to simulate changes in landscape service supply driven by regional policies in a rural region of the Netherlands. This application demonstrates potential trade-offs, which emerge in a spatially explicit way in the region over time. It illustrates the potential relevance of modelling landscape service dynamics for environmental management and decision making.

The impact of first-generation biofuels on the depletion of the global phosphorus reserve

The large majority of biofuels to date is "first-generation" biofuel made from agricultural commodities. All first-generation biofuel production systems require phosphorus (P) fertilization. P is an essential plant nutrient, yet global reserves are finite. We argue that committing scarce P to biofuel production involves a trade-off between climate change mitigation and future food production. We examine biofuel production from seven types of feedstock, and find that biofuels at present consume around 2% of the global inorganic P fertilizer production. For all examined biofuels, with the possible exception of sugarcane, the contribution to P depletion exceeds the contribution to mitigating climate change. The relative benefits of biofuels can be increased through enhanced recycling of P, but high increases in P efficiency are required to balance climate change mitigation and P depletion impacts. We conclude that, with the current production systems, the production of first-generation biofuels compromises food production in the future.

Tumors of the infratemporal fossa

Neoplastic processes involving the infratemporal fossa may originate from the tissues in the region, but more often are the result of extension from neighboring structures. Metastatic lesions located in the region are rarely encountered. Because of its concealed localization, tumors may remain unnoticed for some time. Clinical signs and symptoms often arise late, are insidious, and may be mistakenly attributed to other structures. The close proximity of the area to the intracranial structures, the orbit, the paranasal sinuses, the nasopharynx, and the facial area demands careful planning of surgical excision and combined procedures may be called for. Modern imaging techniques have made three-dimensional visualization of the extent of the pathology possible. Treatment depends on the histopathology and staging of the tumor. Several surgical approaches have been developed over the years. Radical tumor excision with preservation of the quality of life remain the ultimate goal for those tumors where surgery is indicated. Experience over a decade with various pathologies is presented.

Modelling recovery from soil acidification in European forests under climate change

A simple soil acidification model was applied to evaluate the effects of sulphur and nitrogen emission reductions on the recovery of acidified European forest soils. In addition we included the effects of climate change on soil solution chemistry, by modelling temperature effects on soil chemical processes and including temperature and precipitation effects on nitrogen uptake and on leaching. Model results showed a strong effect of the emission reduction scenarios on soil solution chemistry. Using the Current Legislation (CLE) scenario, the forest area in Europe with soil solution Al/Bc >1 mol mol(-1) (a widely used critical limit) decreased from about 4% in 1990 to about 1.7% in 2050. Under Maximum Feasible Reductions (MFR), the exceeded area will be <1% in 2050. In addition, the area where limits for the nitrate concentration in soils are violated is predicted to be smaller under MFR than under CLE. Using the most stringent criterion for nitrate ([NO(3)] <0.3mg l(-1)), the area with nitrate concentrations in excess of the critical limit is about 33% in 2050 under CLE, but only 12% under MFR. Recovery, i.e. attaining non-violation of the criterion, is also much faster under MFR than under CLE. Climate change leads to higher weathering rates and nitrogen uptake in the model, but positive effects on recovery from acidification are limited compared to current climate, and differences between the A1 and B2 climate change scenarios were small. Target loads for 2050 exist for 4% of the area for Al/Bc=1 and for 12% of the area when using a criterion of ANC=0 for the soil solution. In about 30% of the area where meaningful target loads exists, the computed target load is lower than the deposition under MFR, and thus cannot be attained with current emission abatement technologies.

A comparison of baseline methodologies for 'Reducing Emissions from Deforestation and Degradation'

BACKGROUND

A mechanism for emission reductions from deforestation and degradation (REDD) is very likely to be included in a future climate agreement. The choice of REDD baseline methodologies will crucially influence the environmental and economic effectiveness of the climate regime. We compare three different historical baseline methods and one innovative dynamic model baseline approach to appraise their applicability under a future REDD policy framework using a weighted multi-criteria analysis.

RESULTS

The results show that each baseline method has its specific strengths and weaknesses. Although the dynamic model allows for the best environmental and for comparatively good economic performance, its high demand for data and technical capacity limit the current applicability in many developing countries.

CONCLUSION

The adoption of a multi-tier approach will allow countries to select the baseline method best suiting their specific capabilities and data availability while simultaneously ensuring scientific transparency, environmental effectiveness and broad political support.

Quantifying the effectiveness of climate change mitigation through forest plantations and carbon sequestration with an integrated land-use model

BACKGROUND

Carbon plantations are introduced in climate change policy as an option to slow the build-up of atmospheric carbon dioxide (CO2) concentrations. Here we present a methodology to evaluate the potential effectiveness of carbon plantations. The methodology explicitly considers future long-term land-use change around the world and all relevant carbon (C) fluxes, including all natural fluxes. Both issues have generally been ignored in earlier studies.

RESULTS

Two different baseline scenarios up to 2100 indicate that uncertainties in future land-use change lead to a near 100% difference in estimates of carbon sequestration potentials. Moreover, social, economic and institutional barriers preventing carbon plantations in natural vegetation areas decrease the physical potential by 75-80% or more.Nevertheless, carbon plantations can still considerably contribute to slowing the increase in the atmospheric CO2 concentration but only in the long term. The most conservative set of assumptions lowers the increase of the atmospheric CO2 concentration in 2100 by a 27 ppm and compensates for 5-7% of the total energy-related CO2 emissions. The net sequestration up to 2020 is limited, given the short-term increased need for agricultural land in most regions and the long period needed to compensate for emissions through the establishment of the plantations. The potential is highest in the tropics, despite projections that most of the agricultural expansion will be in these regions. Plantations in high latitudes as Northern Europe and Northern Russia should only be established if the objective to sequester carbon is combined with other activities.

CONCLUSION

Carbon sequestration in plantations can play an important role in mitigating the build-up of atmospheric CO2. The actual magnitude depends on natural and management factors, social barriers, and the time frame considered. In addition, there are a number of ancillary benefits for local communities and the environment. Carbon plantations are, however, particularly effective in the long term. Furthermore, plantations do not offer the ultimate solution towards stabilizing CO2 concentrations but should be part of a broader package of options with clear energy emission reduction measures.

Sustainability or collapse: what can we learn from integrating the history of humans and the rest of nature?

Understanding the history of how humans have interacted with the rest of nature can help clarify the options for managing our increasingly interconnected global system. Simple, deterministic relationships between environmental stress and social change are inadequate. Extreme drought, for instance, triggered both social collapse and ingenious management of water through irrigation. Human responses to change, in turn, feed into climate and ecological systems, producing a complex web of multidirectional connections in time and space. Integrated records of the co-evolving human-environment system over millennia are needed to provide a basis for a deeper understanding of the present and for forecasting the future. This requires the major task of assembling and integrating regional and global historical, archaeological, and paleoenvironmental records. Humans cannot predict the future. But, if we can adequately understand the past, we can use that understanding to influence our decisions and to create a better, more sustainable and desirable future.

Global Desertification: Building a Science for Dryland Development

In this millennium, global drylands face a myriad of problems that present tough research, management, and policy challenges. Recent advances in dryland development, however, together with the integrative approaches of global change and sustainability science, suggest that concerns about land degradation, poverty, safeguarding biodiversity, and protecting the culture of 2.5 billion people can be confronted with renewed optimism. We review recent lessons about the functioning of dryland ecosystems and the livelihood systems of their human residents and introduce a new synthetic framework, the Drylands Development Paradigm (DDP). The DDP, supported by a growing and well-documented set of tools for policy and management action, helps navigate the inherent complexity of desertification and dryland development, identifying and synthesizing those factors important to research, management, and policy communities.

Ecosystem service supply and vulnerability to global change in Europe

Global change will alter the supply of ecosystem services that are vital for human well-being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.

The use of elastic intramedullary nailing in the stabilisation of paediatric fractures

The treatment of paediatric long-bone fractures remains controversial. Elastic intramedullary nailing has been proposed as an alternative for the treatment of paediatric long-bone fractures.

PATIENTS

We treated 68 children in a time span of 9 years with 32 fractures of the forearm, 27 fractures of the femur and nine fractures of the tibia. The mean age was 8.3 years and the mean admission time 2.6 days.

RESULTS

Mean consolidation time was 7.9 weeks for the forearm fractures, 11.9 weeks for the femur fractures and 10.6 weeks for the tibial fractures. Full weight bearing for the latter two fracture types was allowed within the first week. There were no major complications. The complications encountered were three hydrops of the knee, four low-grade infections and one delayed union. Leg length discrepancy was only seen in five patients (18%) and was less than 2 cm.

DISCUSSION

In femur fractures, we let the parents decide between skeletal traction and intramedullary rods. When confronted with the possible complications (operation-related complications and infection) compared to the advantages (early weight bearing and short admission time), they almost always choose the operative approach. In our opinion, elastic intramedullary nailing is an excellent treatment option for diaphyseal fractures in children with skeletal immaturity, especially of the femur.

Nocardia farcinica as the causative agent in a primary psoas abscess in a previously healthy cattle inspector

A 42-year-old, previously healthy cattle inspector presented with a 7-day history of fever, a painful left knee, malaise and muscular pain. He did not suffer from an underlying disease, nor was he immunocompromised. After 12 days of hospitalization, a unilocular abscess in the left psoas muscle was diagnosed. Nocardia farcinica was isolated from the aspirate. No connection with his work could be demonstrated. The patient was successfully treated with trimethoprim-sulfamethoxazole for 11 months.

An injectable calcium phosphate cement as a bone-graft substitute in the treatment of displaced lateral tibial plateau fractures

In the treatment of displaced tibial plateau fractures, filling the resultant metaphyseal defect is essential for maintaining reduction. This study reports on 14 patients with an average age of 53 (range 34-63) years who sustained such a fracture and whose tibial defect was augmented with an injectable calcium phosphate cement under arthroscopic and fluoroscopic control. Eight fractures were treated with subcortical percutaneous screw fixation, plates were used in four cases and two fractures were treated with bone cement only. Full weight-bearing was allowed after 6-12 weeks. At the last follow-up which averaged 28 (range 18-47) months, the reduction achieved at the index operation was not altered in any of the patients except one. Most patients recorded little or no pain with an average VAS score of 1.2 (0-3.4). Ten patients had no limitation of their walking distance. Patient satisfaction was good or excellent in 12 cases. Flexion averaged 140 degrees (range 130-150 degrees ) and extension was unlimited in 13 patients. The Lysholm knee score averaged 80 and the Knee Society score 180 (range 127-195). In our opinion the injectable calcium phosphate cement used here is a promising alternative for filling metaphyseal defects in the treatment of displaced tibial plateau fractures.

Inhibition of cytokine-induced NF-kappaB activation by adenovirus-mediated expression of a NF-kappaB super-repressor prevents beta-cell apoptosis

Cytokine-induced beta-cell death is an important event in the pathogenesis of type 1 diabetes. The transcription factor nuclear factor-kappaB (NF-kappaB) is activated by interleukin-1beta (IL-1beta), and its activity promotes the expression of several beta-cell genes, including pro- and anti-apoptotic genes. To elucidate the role of cytokine (IL-1beta + gamma-interferon [IFN-gamma])-induced expression of NF-kappaB in beta-cell apoptosis, rat beta-cells were infected with the recombinant adenovirus AdIkappaB((SA)2), which contained a nondegradable mutant form of inhibitory kappaB (IkappaB((SA)2), with S32A and S36A) that locks NF-kappaB in a cytosolic protein complex, preventing its nuclear action. Expression of IkappaB((SA)2) inhibited cytokine-stimulated nuclear translocation and DNA-binding of NF-kappaB. Cytokine-induced gene expression of several NF-kappaB targets, namely inducible nitric oxide synthase, Fas, and manganese superoxide dismutase, was prevented by AdIkappaB((SA)2), as established by reverse transcriptase-polymerase chain reaction, protein blot, and measurement of nitrite in the medium. Finally, beta-cell survival after IL-1beta + IFN-gamma treatment was significantly improved by IkappaB((SA)2) expression, mostly through inhibition of the apoptotic pathway. Based on these findings, we conclude that NF-kappaB activation, under in vitro conditions, has primarily a pro-apoptotic function in beta-cells.

The efficacy of Xialine in patients with xerostomia resulting from radiotherapy for head and neck cancer: a pilot-study

Changes in subjective sensations due to xerostomia before and after administration of Xialine, a xanthan gum-based saliva substitute, were evaluated in 30 patients with radiation-induced xerostomia using the QLQ-H&N35. Xerostomia in general decreased with both Xialine and placebo to almost the same degree. A trend was seen for Xialine to improve problems with speech and senses.

Differential expression and function of the Drosophila Pax6 genes eyeless and twin of eyeless in embryonic central nervous system development

We analyzed the expression and function of eyeless (ey) and twin of eyeless (toy) in the embryonic central nervous system (CNS) of Drosophila. Both genes are differentially expressed in specific neuronal subsets (but not in glia) in every CNS neuromere, and in the brain, specific cell populations co-expressing both proteins define a longitudinal domain which is intercalated between broad exclusive expression domains of ey and toy. Studies of genetic null alleles and dsRNA interference did not reveal any gross neuroanatomical effects of ey, toy, or ey/toy elimination in the embryonic CNS. In contrast, targeted misexpression of ey, but not of toy, resulted in profound axonal abnormalities in the embryonic ventral nerve cord and brain.

Quantitative transcript imaging in normal and heat-shocked Drosophila embryos by using high-density oligonucleotide arrays

Embryonic development in Drosophila is characterized by an early phase during which a cellular blastoderm is formed and gastrulation takes place, and by a later postgastrulation phase in which key morphogenetic processes such as segmentation and organogenesis occur. We have focused on this later phase in embryogenesis with the goal of obtaining a comprehensive analysis of the zygotic gene expression that occurs during development under normal and altered environmental conditions. For this, a functional genomic approach to embryogenesis has been developed that uses high-density oligonucleotide arrays for large-scale detection and quantification of gene expression. These oligonucleotide arrays were used for quantitative transcript imaging of embryonically expressed genes under standard conditions and in response to heat shock. In embryos raised under standard conditions, transcripts were detected for 37% of the 1,519 identified genes represented on the arrays, and highly reproducible quantification of gene expression was achieved in all cases. Analysis of differential gene expression after heat shock revealed substantial expression level changes for known heat-shock genes and identified numerous heat shock-inducible genes. These results demonstrate that high-density oligonucleotide arrays are sensitive, efficient, and quantitative instruments for the analysis of large scale gene expression in Drosophila embryos.

Global biodiversity scenarios for the year 2100

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

Global biodiversity scenarios for the year 2100

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

The properties of a tRNA-specific adenosine deaminase from Drosophila melanogaster support an evolutionary link between pre-mRNA editing and tRNA modification

Pre-mRNA editing involving the conversion of adenosine to inosine is mediated by adenosine deaminases that act on RNA (ADAR1 and ADAR2). ADARs contain multiple double-stranded RNA(dsRNA)-binding domains in addition to an adenosine deaminase domain. An adenosine deaminase acting on tRNAs, scTad1p (also known as scADAT1), cloned from Saccharomyces cerevisiae has a deaminase domain related to the ADARs but lacks dsRNA-binding domains. We have identified a gene homologous to scADAT1 in the region of Drosophila melanogaster Adh chromosome II. Recombinant Drosophila ADAT1 (dADAT1) has been expressed in the yeast Pichia pastoris and purified. The enzyme has no activity on dsRNA substrates but is a tRNA deaminase with specificity for adenosine 37 of insect alanine tRNA. dADAT1 shows greater similarity to vertebrate ADARs than to yeast Tad1p, supporting the hypothesis of a common evolutionary origin for ADARs and ADATs. dAdat1 transcripts are maternally supplied in the egg. Zygotic expression is widespread initially and later concentrates in the central nervous system.

One-stage lengthening and derotational osteotomy of the femur stabilised with a gamma nail

OBJECTIVES

To study the results of a one-stage lengthening and derotational osteotomy stabilised with a Gamma nail.

DESIGN

Retrospective study.

SETTING

2 hospitals, The Netherlands.

PATIENTS

5 patients after failed osteosynthesis of femoral fractures.

INTERVENTIONS

Mean lengthening of 3 cm and derotation of 30 degrees.

MAIN OUTCOME MEASURES

Complications and functional results, after a mean follow-up of 43 months (range 30-57).

RESULTS

Two patients required dynamisation and a cancellous bone graft to achieve union, which resulted in 1 and 1.5 cm loss of length. One patient had a temporary peroneal neurapraxy. No infections were observed.

CONCLUSIONS

Our method is not an ultimate solution, but is suitable for one-stage lengthening and derotation osteotomies.

Spleen autotransplantation provides restoration of functional splenic lymphoid compartments and improves the humoral immune response to pneumococcal polysaccharide vaccine

After splenectomy, patients have an increased risk of overwhelming post-splenectomy infection (OPSI) or sepsis involving encapsulated bacteria such as pneumococcus. The value of spleen autotransplantation after splenectomy because of trauma has long been questioned. Much attention has been given to the restoration of mononuclear phagocyte system (MPS) function, which appeared to be similar to that of splenectomized individuals. The presence of specific anti-pneumococcal antibodies may enhance phagocytosis of opsonized bacteria by other parts of the MPS, as present in the liver. Therefore, in the present study we have evaluated the restoration of the humoral immune response after spleen autotransplantation, especially to pneumococcal capsular polysaccharides (PPS). Wistar rats were divided into three groups which were operated as follows: splenectomy, splenectomy followed by autotransplantation, and sham operation. After 12 weeks the rats were vaccinated with 23-valent pneumococcal vaccine. Blood samples were taken after 3 days, 3 and 6 weeks for anti-PPS IgM and IgG ELISA against types 3, 4, 6, 9, 14 and 23. In addition, immunohistological studies were performed on the autotransplants. Significant antibody titre rises were found in a main proportion of the autotransplanted rats, comparable to sham-operated rats. Splenectomized rats showed as well a significantly lower increase in immunoglobulin levels, as significant differences in the proportion of rats showing a minimum two-fold increase of antibody level, considered to represent an adequate response. The titres were highest 3 days after vaccination. Immunohistochemical studies demonstrated structurally functional autotransplants, including an intact marginal zone. Considering this significant anti- pneumococcal antibody response, spleen autotransplants can be expected to enable an improved humoral response to PPS, and to contribute to protection against OPSI after splenectomy.

Immune response capacity after human splenic autotransplantation: restoration of response to individual pneumococcal vaccine subtypes

OBJECTIVE

To evaluate features of general immune function, in particular the restoration of the humoral immune response to pneumococcal capsular polysaccharides, in humans undergoing a spleen autotransplantation after splenectomy because of trauma.

SUMMARY BACKGROUND DATA

After splenectomy, patients have an increased risk of overwhelming infection or sepsis involving encapsulated bacteria such as pneumococci. The value of human spleen autotransplantation after splenectomy because of trauma has long been questioned. Mononuclear phagocyte system function appeared to be similar to that in splenectomized persons. The presence of specific antipneumococcal antibodies would allow other parts of the mononuclear phagocyte system, such as those in the liver, to phagocytose opsonized bacteria.

METHODS

Ten consecutive patients undergoing splenectomy followed by autotransplantation were compared with the next 14 consecutive patients undergoing splenectomy alone. After a minimum of 6 months, the patients were vaccinated with 23-valent pneumococcal vaccine. Blood samples were taken at the time of vaccination and after 3 and 6 weeks for antipneumococcal capsular polysaccharides IgM and IgG enzyme-linked immunosorbent assay against types 3, 4, 6, 9, 14, and 23. Splenic regrowth was evaluated by scintigraphy.

RESULTS

Surprisingly, several of the nonautotransplanted patients showed scintigraphic activity, indicating the presence of either accessory spleens or traumatic seeding (splenosis). Significant antibody titer increases (more than twofold) were found for both IgM and IgG in the autotransplanted patients. Splenectomized-only patients showed no significant increase in Ig levels in patients without splenic regrowth and partial improvement in patients with splenosis/accessory spleens.

CONCLUSIONS

Considering this significant antipneumococcal antibody increase, spleen autotransplants can be expected to permit an adequate humoral response to pneumococcal infections and presumably also to other TI-2 antigens, and to protect against overwhelming postsplenectomy infection or sepsis.

Splenic epithelial cysts and splenomegaly: diagnosis and management

Splenomegaly is a common problem. In the absence of systemic illness or malignancy splenic cysts must be considered, especially the epithelial variety. For large cysts total splenectomy has long been recommended. Recognition of the risk of an overwhelming postsplenectomy infection (OPSI), especially in children, has led to spleen conserving surgery. We describe the use of an absorbable Vicryl net after partial splenectomy with total cystectomy in the management of splenic epithelial cysts.

Fc-receptor function after human splenic autotransplantation

Mononuclear phagocytic function was studied using the Fc-receptor test in 24 patients who underwent splenectomy, ten of whom underwent splenic autotransplantation. All patients undergoing autotransplantation had mononuclear phagocyte system (MPS) activity at the transplantation sites. In eight of the 14 patients who did not undergo autotransplantation there was also scintigraphic MPS activity indicative of ectopic splenic tissue. Although the Fc-receptor test showed delayed and monoexponential blood clearance in all patients after splenectomy, there were no significant differences between the patient groups. Autotransplantation of small amounts of splenic tissue after splenectomy provides some MPS activity but is inadequate for blood clearance.