WWF Tanzania
nonprofitDar es Salaam, Tanzania
Research output, citation impact, and the most-cited recent papers from WWF Tanzania (Tanzania). Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from WWF Tanzania
Abstract Aim Large trees (d.b.h. ≥ 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan‐tropical scales. Location Pan‐tropical. Methods Aboveground biomass ( AGB) was calculated for 120 intact lowland moist forest locations. Linear regression was used to calculate variation in AGB explained by the density of large trees. Akaike information criterion weights ( AICc ‐wi) were used to calculate averaged correlation coefficients for all possible multiple regression models between AGB /density of large trees and environmental and species trait variables correcting for spatial autocorrelation. Results Density of large trees explained c . 70% of the variation in pan‐tropical AGB and was also responsible for significantly lower AGB in Neotropical [287.8 (mean) ± 105.0 ( SD ) M g ha −1 ] versus Palaeotropical forests (Africa 418.3 ± 91.8 M g ha −1 ; Asia 393.3 ± 109.3 M g ha −1 ). Pan‐tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature in the warmest month (negative) and rainfall in the wettest month (positive), but results were not always consistent among continents. Main conclusions Density of large trees and AGB were significantly associated with climatic variables, indicating that climate change will affect tropical forest biomass storage. Species trait composition will interact with these future biomass changes as they are also affected by a warmer climate. Given the importance of large trees for variation in AGB across the tropics, and their sensitivity to climate change, we emphasize the need for in‐depth analyses of the community dynamics of large trees.
OBJECTIVE: To appraise the literature on the effect of initial renal replacement therapy (RRT) modality on clinical outcomes. DESIGN: Systematic review and meta-analysis. SETTING: Academic medical center. PATIENTS AND PARTICIPANTS: Adult critically ill patients with acute kidney injury. INTERVENTIONS: Continuous vs. intermittent RRT. MEASUREMENTS AND RESULTS: MEDLINE, EMBASE, Cochrane Controlled Clinical Trials Register, and other sources were searched. We identified nine unique randomized trials (n = 1,403). No trial satisfied all quality indicators and several had limitations related to selection bias, randomization, imbalances in patient characteristics, and high treatment crossover. No trial standardized the timing, criteria, for initiation or dose of RRT. There was no statistical evidence that initial modality influenced mortality (odds ratio, 0.99; 95% confidence interval, 0.78-1.26, p = .93; I2 = 11%; nine trials, n = 1,403) or recovery to RRT independence (odds ratio, 0.76; 95% confidence interval, 0.28-2.07, p = .59; I2 = 0%; four trials, n = 306). There was suggestion that continuous RRT had fewer episodes of hemodynamic instability and better control of fluid balance. CONCLUSIONS: We identified numerous issues related to study design, conduct, and quality that dispute the validity and question any inferences that can be drawn from these trials. In the context of these limitations, the initial RRT modality did not seem to affect mortality or recovery to RRT independence. There is urgent need for additional high-quality and suitably powered trials to adequately address this issue.
Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases (IBD) that often involve organs other than those of the gastrointestinal tract. These nonintestinal affections are termed extraintestinal symptoms. Differentiating the true extraintestinal manifestations of inflammatory bowel diseases from secondary extraintestinal complications, caused by malnutrition, chronic inflammation or side effects of therapy, may be difficult. This review concentrates on frequency, clinical presentation and therapeutic implications of extraintestinal symptoms in inflammatory bowel diseases. If possible, extraintestinal manifestations are differentiated from extraintestinal complications. Special attention is given to the more recently described sites of involvement; i.e. thromboembolic events, osteoporosis, pulmonary involvement and affection of the central nervous system.
Marine protected areas (MPAs) are a popular conservation strategy, but their impacts on human welfare are poorly understood. To inform future research and policy decisions, we reviewed the scientific literature to assess MPA impacts on five indicators of human welfare: food security, resource rights, employment, community organization, and income. Following MPA establishment, food security generally remained stable or increased in older and smaller MPAs. The ability of most fishing groups to govern MPA resources changed. Increased resource rights were positively correlated with MPA zoning and compliance with MPA regulations. Small sample sizes precluded statistical tests of the impacts of MPAs on employment, community organization, and income. Our results demonstrate that MPAs shape the social well-being and political power of fishing communities; impacts (positive and negative) vary within and among social groups; and social impacts are correlated with some--but not all--commonly hypothesized explanatory factors. Accordingly, MPAs may represent a viable strategy for enhancing food security and empowering local communities, but current practices negatively affect at least a minority of fishers. To inform policy making, further research must better document and explain variation in the positive and negative social impacts of MPAs.
River flows connect people, places, and other forms of life, inspiring and sustaining diverse cultural beliefs, values, and ways of life. The concept of environmental flows provides a framework for improving understanding of relationships between river flows and people, and for supporting those that are mutually beneficial. Nevertheless, most approaches to determining environmental flows remain grounded in the biophysical sciences. The newly revised Brisbane Declaration and Global Action Agenda on Environmental Flows (2018) represents a new phase in environmental flow science and an opportunity to better consider the co-constitution of river flows, ecosystems, and society, and to more explicitly incorporate these relationships into river management. We synthesize understanding of relationships between people and rivers as conceived under the renewed definition of environmental flows. We present case studies from Honduras, India, Canada, New Zealand, and Australia that illustrate multidisciplinary, collaborative efforts where recognizing and meeting diverse flow needs of human populations was central to establishing environmental flow recommendations. We also review a small body of literature to highlight examples of the diversity and interdependencies of human-flow relationships-such as the linkages between river flow and human well-being, spiritual needs, cultural identity, and sense of place-that are typically overlooked when environmental flows are assessed and negotiated. Finally, we call for scientists and water managers to recognize the diversity of ways of knowing, relating to, and utilizing rivers, and to place this recognition at the center of future environmental flow assessments. This article is categorized under: Water and Life > Conservation, Management, and Awareness Human Water > Water Governance Human Water > Water as Imagined and Represented.
Abstract Sand mining (used here as a generic term that includes mining of any riverine aggregates regardless of particle size) is a global activity that is receiving increasing media attention due to perceived negative environmental and social impacts. As calls grow for stronger regulation of mining, there is a need to understand the scientific evidence to support effective management. This paper summarizes the results of a structured literature review addressing the question, “What evidence is there of impacts of sand mining on ecosystem structure, process, and biodiversity in rivers, floodplains, and estuaries?” The review found that most investigations have focused on temperate rivers where sand mining occurred historically but has now ceased. Channel incision was the most common physical impact identified; other physical responses, including habitat disturbance, alteration of riparian zones, and changes to downstream sediment transport, were highly variable and dependant on river characteristics. Ecosystem attributes affected included macroinvertebrate drift, fish movements, species abundance and community structures, and food web dynamics. Studies often inferred impacts on populations, but supporting data were scarce. Limited evidence suggests that rivers can sustain extraction if volumes are within the natural sediment load variability. Significantly, the countries and rivers for which there is science‐based evidence related to sand mining are not those where extensive sand mining is currently reported. The lack of scientific and systematic studies of sand mining in these countries prevents accurate quantification of mined volumes or the type, extent, and magnitude of any impacts. Additional research into how sand mining is affecting ecosystem services, impacting biodiversity and particularly threatened species, and how mining impacts interact with other activities or threats is urgently required.
Abstract In efforts to protect the world's oceans, the Convention on Biological Diversity has moved the goal of establishing marine protected areas (MPAs) to cover 10% of the ocean from 2012 to 2020. This adjustment suggests that the rush to establish MPAs without proper resources does not resolve conservation problems. In fact, such actions may create a false sense of protection that camouflages degradation of marine ecosystems on regional scales. To exemplify this phenomenon, we reviewed MPA efficacy in the Gulf of California, Mexico, where some 23,300 km 2 have been decreed as MPAs. With the exception of Cabo Pulmo National Park, MPAs have not met conservation or sustainability goals. We examined MPA budgets and foundations’ investment in the region and found that funding for management is not the limiting factor in MPA efficacy, although funding for enforcement may be deficient. We conclude that MPAs have failed because of insufficient no‐take zones, lack of enforcement, poor governance, and minimal community involvement. We need a new philosophy to implement MPAs to take advantage of the scientific knowledge and monetary investment that have been generated worldwide and ensure that they complement effective fisheries management outside their borders.
Effective HER activity on layered double hydroxide nanosheets through a plasma etching strategy.
Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.
Abstract A hybrid LES‐RANS modelling approach is proposed. RANS is used in the near wall regions (y+≲60), and the turbulence is modelled with a k–ω model. LES is used in the remaining part of the flow, and the SGS turbulence is modelled with a one‐equation ksgs model. The same continuity and momentum equations are solved throughout the domain, the only difference being that the turbulent viscosity is taken from the k–ω model in the RANS region, and from the one‐equation ksgs model in the LES region. The new modelling approach is applied to two incompressible flow test cases. They are fully developed flow in a plane channel and the flow over a 2D‐hill in a channel. Copyright © 2003 John Wiley & Sons, Ltd.
Climate-smart agriculture (CSA) is agriculture that increases productivity, improves resilience, and mitigates climate change. Smallholder adoption of farming technology is necessary to speed the transition to CSA. Here, we assessed the determinants of adoption of five technologies that can help achieve some of the CSA outcomes in smallholder farms in Tanzania. They included: crop and livestock diversification, irrigation, application of chemical fertilizers, and agroforestry. Using data collected from 821 farming households, a multivariate probit model was employed to evaluate the determinants of adoption, allowing for examination of synergies and trade-offs between the technologies. Application of chemical fertilizers was fairly well adopted (34% of farmers), while irrigation was least adopted (26%). Some technologies, including crop diversification and irrigation, as well as application of chemical fertilizer and agro-forestry, complemented each other. Trade-offs were observed between livestock diversification and irrigation. Female control of farm resources, farm location, and household resources were major determinants of adoption. We therefore, recommend strategies that seeks to enhance building household resource as pathway for improved adoption of new technologies.
For magnetic resonance, the established class of intravenous contrast media is the gadolinium-based contrast agents. In the 3 decades since initial approval, these have proven in general to be very safe for human administration. However, in 2006, a devastating late adverse reaction to administration of the less stable gadolinium-based contrast agents was identified, nephrogenic systemic fibrosis. The result of actions taken by the European Medicines Agency and the US Food and Drug Administration, stratifying the agents by risk and contraindicating specific agents in severe renal dysfunction, has led to no new cases being identified in North America or Europe. Subsequently, in 2014, long-term deposition in the brain of gadolinium was first shown, after administration of 2 nonionic linear chelates, gadodiamide, and gadopentetate dimeglumine. This has led to an intense focus on the question of in vivo distribution, possible dechelation, and subsequent deposition of gadolinium, together with substantial clarification of the phenomenon as well as stratification of the agents on this basis. This review focuses on 8 critical questions regarding gadolinium deposition in the brain and body, with the answers and discussion therein important for future regulatory decisions and clinical practice. It is now clear that dechelation of gadolinium occurs in vivo with the linear agents and is responsible for this phenomenon, with key experts in the field recommending, except where there is no suitable alternative, a shift in clinical practice from the linear to macrocyclic agents. In addition, on March 10, 2017, the Pharmacovigilance and Risk Assessment Committee of the European Medicines Agency recommended suspension of the marketing authorization for 4 linear gadolinium contrast agents-specifically Omniscan, Optimark, Magnevist, and MultiHance (gadodiamide, gadoversetamide, gadopentetate dimeglumine, and gadobenate dimeglumine)-for intravenous injection. Cited in the report was convincing evidence of gadolinium deposition in the brain months after injection of these linear agents. Primovist/Eovist (gadoxetic acid disodium) will remain available, being used at a lower dose for liver imaging, because it meets an important diagnostic need. In addition, a formulation of Magnevist for intra-articular injection will remain available because of its very low gadolinium concentration.
Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations.
There is a prevailing view that sarcomas arising in dermatofibrosarcoma protuberans (DFSP) have a higher risk of metastasis than ordinary DFSP, but these data are based on cases with variable and often suboptimal treatment. There has not been a large study of sarcomas arising in DFSP in which all cases were treated by wide local excision, thereby arguably altering outcome. Clinicopathologic features of 18 cases of sarcomas arising in DFSP treated by wide local excision and having follow up of at least 5 years were analyzed. An estimate of the proportion of sarcoma and DFSP was made. The number of mitotic figures and degree of CD34 immunoreactivity were assessed in each case. The cohort included 13 females and 5 males (age, 23-87 yrs; median, 47 yrs). The tumors involved the trunk (7), scalp (4), extremities (4), and inguinal region (3), and ranged from 1.5 to 7 cm (median, 4 cm). Sarcoma occurred de novo in 15 cases and in a recurrence in three. Sarcomas resembled fibrosarcoma (17) or malignant fibrous histiocytoma (1) and occupied between 20% and 80% of the tumor (median, 60%). Mitotic activity ranged from 2 to 16 per 10 high-power field (HPF; median 7 per 10 HPF) in the sarcomatous component and 0 to 3 per 10 HPF (median, 1 per 10 HPF) in the DFSP component. All tumors expressed CD34 in the DFSP component but only nine (50%) in the sarcomatous component. All patients were treated by wide local excision with negative margins; three additionally received radiation. Four patients (22%) developed recurrences, but none developed metastasis during the follow-up period of 62 months to 17 years (median, 81.5 mos). In contrast to earlier studies, we demonstrate that patients with sarcomas arising in DFSP do not have an increased risk of distant metastasis within a 5-year follow-up period, provided they are treated by wide local excision with negative margins. This probably reflects the fact that wide local excision results in eradication of local tumor, thereby eliminating the source for subsequent dissemination. However, we cannot completely exclude the possibility that tumors in which clear margins are achieved represent a less aggressive subset, as has been suggested for high-grade extremity sarcomas. Previous studies showing increased metastasis for sarcomas arising in DFSP should be re-evaluated to determine if, with treatment stratification, metastatic rate varies.
Fourteen examples of an unusual mesenchymal tumor characterized by sheets and fascicles of mitotically inactive, hemosiderin-stippled, spindled, and pleomorphic cells, situated around an angiectatic vasculature, are described. The 14 tumours developed in eight women and six men (aged 32-83 years) and ranged in size from 2.3 to 8 cm. Eleven cases presented in the subcutaneous tissues, of which eight were located in the lower extremity. All featured prominent clusters of thin-walled ectatic vessels surrounded by perivascular hyaline material representing a combination of fibrin and collagen. In three cases the perivascular hyalinization was so extensive that it constituted more than half of the total tumor area. The tumor cells were similar to those of malignant fibrous hystiocytoma but differed from them by the presence of prominent intranuclear cytoplasmic inclusions, the extreme scarcity of mitotic figures, and the occasional presence of CD-34 expression. These tumors also shared several features with neurilemomas, such as their unusual vasculature, intranuclear cytoplasmic inclusions, lack of mitotic figures, and abundance of mast cells. They could be distinguished from neurilemomas, however, by the usual presence of infiltrative margins and the absence of S-100 protein. Follow-up information on eight patients (6 months to 25 years) indicated recurrences in four cases, with one of the three patients experiencing numerous recurrences over a 25-year period. No patient has developed metastases, however. We suggest that this tumor is a low-grade sarcoma of uncertain lineage in which the vascular changes are, in part, reflective of its slow growth.
The hand-plucking method for estimation of bite size and nutritive quality was tested for steers grazing at low stocking rates on heathland and in riverine grassland.Vegetation height, standing crop, and cover of distinct plant categories were determined in 13 sampling periods over 2 years.In each period bite size was estimated with 4 esophageally fistulated steers.Bite counts on different plant categories were made during sampling.The plant categories were sampled separately by hand-plucking and weighed to determine plucking size.Extrusa and handplucked samples mere analyzed for concentrations of nitrogen and calcium.Vegetation height was a more accurate predictor of plucking size than standing crop.A curvilinear relationship was derived between plucking size and bite size.The nutritive quality of estrusa and hand-plucked samples was not significantly different.It is concluded that the application of the hand-plucking method appears successful when a stratified sampling approach to hand-plucking is followed.Future studies should esamine operator-biases and horn these can be minimized.Key Words: bite size, diet quality, hand-plucking Diet selection, food intake, and diet quality of herbivores can be estimated by simulation of the observed diet by hand-plucking.The method is rapid, inexpensive, and simple.It often is the only feasible method to investigate the diet of free-ranging or wild herbivores in heterogeneous environments.Unfortunately, it is subject to a mostly unknown bias as the simulation of the graz-This paper forms o part of a Ph.D. [hew,.I would like to thank Prof. H.H.T. Prim.Prof. L. 'I hlannrtje and 3 anonymow referees for the constructive criticism on the manuwipt.Johan Scheele and Teuz Bleyenherg.Department of Agronomy, provided inwlwble hrlp in taking cnre of the ti\rulated steers.I am furthermore very much indebted to hlaurits Gleichmnn
Human activities change the structure and function of the environment with cascading impacts on human health, a concept known as "planetary health." Agroforestry—the management of trees with crops and livestock—alters microclimates, hydrology, biogeochemistry, and biodiversity. Besides the nutritional benefits of increased fruit consumption, however, the ways agroforestry affects human health are rarely articulated. This review makes that link. We analyze the pathways through which tree-based farm and landscape change affect food and nutrition security, the spread of infectious disease, the prevalence of non-communicable diseases, and human migration in Sub-Saharan Africa. The available evidence suggests that, despite some increased risks of infectious disease, agroforestry is likely to improve a diverse range of pressing health concerns. We therefore examine the factors determining agroforestry use and identify three drivers of social and environmental change that will determine the future uptake of agroforestry in the region.
We examined the immunofluorescence and ultrastructural changes of insulin-producing B cells in the center and at the periphery of islets of Langerhans during in vivo stimulation by glucose and glibenclamide. A decreased insulin immunostaining was detected in islets from the splenic rat pancreas after 1.5 h of glucose stimulation. By contrast, immunofluorescence changes became apparent in islets from the duodenal pancreas only after greater than 3 h of hyperglycemia. In both cases, the immunolabeling of central B cells decreased before that of peripheral B cells. Similar changes were seen following in vivo stimulation of insulin secretion by glibenclamide. At the ultrastructural level, hyperglycemia decreased the volume density of B cell secretory granules and increased that of rough endoplasmic reticulum and Golgi apparatus. These changes were also detected earlier in central than in peripheral B cells and earlier in splenic than in duodenal islets. The data show that B cells form a heterogeneous population in vivo.
Using data on Nielsen ratings for locally televised NBA basketball games, we find strong evidence that viewership increases when there is greater participation by white players. This finding controls for a wide variety of other factors that could systematically affect Nielsen ratings, and signifies the presence of customer discrimination in the market for NBA players. We also find that higher Nielsen ratings allow NBA teams to realize greater advertising revenues, meaning that the marginal revenue product of white players exceeds that of comparable black players. This factor explains much of the race‐based salary gap that exists in professional basketball.
Cholinergic afferents to the amygdala from the basal forebrain were studied using di-isopropyl fluorophosphate-AChE histochemistry in combination with retrograde tracing using various fluorescent dyes. Cells sending their axons to the amygdala and staining intensely for AChE were located mainly in the nucleus of the substantia innominata. They also were found in the ventral part of the globus pallidus, the horizontal limb of the nucleus tractus diagonalis Broca, and the nucleus interstitialis ansae lenticularis. A correspondence was established between these cells and cells staining for choline acetyltransferase by immunohistochemistry in both distribution and morphology. Non-cholinergic neurons which send their axons to the amygdala also were found in the substantia innominata complex.