10 research outputs found
Rural-Urban Economic Linkages: The Case of Dodoma Region, Tanzania
The government of Tanzania has been active in attempting to stimulate national economic development since independence, and has used such methods as concentration of rural population in village settlements, the promotion of nine growth centres into secondary cities, and the decentralisation of both the decision-making machinery and economic activities, in particular industry, from Dar-es-Salaam, but with only limited success. Tanzania is still using the basic pattern of urban centres and structures developed during the colonial period, and the problem is that this pattern was designed to serve a different function and purpose from that of today. This study aims to evaluate Tanzania's current urban spatial structure, and the associated economic linkages, in relation to its present development goals. Specifically, it attempts to evaluate one aspect of the spatial economic structure, that of the urban hierarchy, in facilitating the flows of goods, services and information between the rural and urban sectors of the country. This is approached by evaluating the extent to which existing spatial structure has reduced both the primacy of Dar-es-Salaam and the existence of regional inequalities, has attracted industrial growth away from the coastal and northern zones, and has achieved the development objectives of the state of Tanzania. The results of this study show that the dominance of the coastal areas, and, in particular, the metropolitan city of Dar-es-Salaam, the northern centres of Arusha, Moshi, Tanga and Morogoro over the other centres and regions of Tanzania, has not been weakened. The growth centre strategy has not been able to reduce either urban primacy, and in particular the primacy of Dar-es-Salaam, or regional inequalities. It can be concluded that although Tanzania's development goals have changed sincelndependence, the spatial organisation of its towns and service centres, its communication and transport networks and the economic links between them have remained largely unchanged. The present urban structure in Tanzania, and the Dodoma study region, is not appropriate for the nation's current development goals, and has not succeeded in bringing about either the desired rural development or regional equity
No. 15: The State of Food Security in Manzini, Swaziland
This study of the food security situation of the poor in Manzini, Swazilandâs economic hub, formed part of AFSUNâs baseline survey of eleven Southern African cities. It found that the urban poor here are less food secure than in any of the other cities in the survey. On the basis of the findings presented in this paper, AFSUN makes several policy recommendations to deal with food security challenges in the poor urban areas of Swaziland. Among these is that government needs to target urban households specifically in addition to its focus on poverty in rural areas. A more national approach that covers both rural and urban areas will help Swaziland to move towards the achievement of the Millennium Development Goal to reduce hunger by 50%. Because households that are severely food insecure tend to be large, female-headed and female-centred, and have a narrow range of livelihood strategies, it is vital for policies that address urban food security to appreciate the complex relationship between household food security and a range of variables such as income, gender and household size
Tailored photon-pair generation in optical fibers
We experimentally control the spectral structure of photon pairs created via
spontaneous four-wave mixing in microstructured fibers. By fabricating fibers
with designed dispersion, one can manipulate the photons' wavelengths, joint
spectrum, and, thus, entanglement. As an example, we produce photon-pairs with
no spectral correlations, allowing direct heralding of single photons in
pure-state wave packets without filtering. We achieve an experimental purity of
, while theoretical analysis and preliminary tests suggest 94.5%
purity is possible with a much longer fiber
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Inward and Outward FDI Country Profiles, Second Edition
This second edition contains a series of 77 standardized country profiles dealing with the inward and outward foreign direct investment (FDI) performance of 40 economies. The profiles have been peer-reviewed by a global network of experts. The publication is intended to contribute to the analysis of trends in foreign direct investment and policy issues related to them. More specifically, the individual profiles discuss FDI trends and developments (country-level developments, the corporate players); effects of the recent global crises; and the policy scene. Each profile contains a standard set of tables, including on FDI stocks and flows, sectoral and geographical FDI distributions, the largest M&As and greenfield investments, the principal foreign affiliates (for inward FDI), and the principal multinational enterprises (for outward FDI). The standardized template used to produce the profiles allows cross-country comparisons. The volume is meant to be a reference tool for anyone interested in foreign direct investment
No. 15: The State of Food Security in Manzini, Swaziland
This study of the food security situation of the poor in Manzini, Swazilandâs economic hub, formed part of AFSUNâs baseline survey of eleven Southern African cities. It found that the urban poor here are less food secure than in any of the other cities in the survey. On the basis of the findings presented in this paper, AFSUN makes several policy recommendations to deal with food security challenges in the poor urban areas of Swaziland. Among these is that government needs to target urban households specifically in addition to its focus on poverty in rural areas. A more national approach that covers both rural and urban areas will help Swaziland to move towards the achievement of the Millennium Development Goal to reduce hunger by 50%. Because households that are severely food insecure tend to be large, female-headed and female-centred, and have a narrow range of livelihood strategies, it is vital for policies that address urban food security to appreciate the complex relationship between household food security and a range of variables such as income, gender and household size
Performance of Autumn and Spring Calving Holstein Dairy Cows with Different Levels of Environmental Exposure and Feeding Strategies
Environmental exposure during confinement and feeding strategy affects cow behavior, nutrient utilization, and performance. Milk production and composition, body condition score, non-esterified fatty acids, and beta-hydroxybutyrate were determined during a full lactation in cows submitted to (a) grazing + partial confinement in outdoor soil-bedded pens with shade structures (OD-GRZ); (b) grazing + partial confinement in a compost-bedded pack barn with cooling capacity (CB-GRZ); or (c) total confinement (same facilities as CB-GRZ) and fed TMR ad libitum (CB-TMR). Autumn (ACS) and spring (SCS) calving season cows were used for each treatment, except for CB-TMR (only SCS). In ACS, treatments did not differ in any variable, possibly due to mild weather. In SCS, milk production was higher in CB-TMR than CB-GRZ, which in turn produced more milk than OD-GRZ. Differences coincided with heat waves and/or heavy rains (similar grazing conditions and mixed ration DM intake). Milk fat, protein and lactose yield, protein content, and BCS were higher in CB-TMR, without differences between CB-GRZ and OD-GRZ. Cows in OD-GRZ had impaired energy metabolism. Under moderately unfavorable environmental conditions (ACS), when well-managed, OD-GRZ systems could equate to the productive response of CB-GRZ. However, in worse climatic conditions (SCS), performance could be compromised, especially when compared to TMR systems
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Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome
BACKGROUND
In renal Fanconi's syndrome, dysfunction in proximal tubular cells leads to renal losses of water, electrolytes, and low-molecular-weight nutrients. For most types of isolated Fanconi's syndrome, the genetic cause and underlying defect remain unknown.
METHODS
We clinically and genetically characterized members of a five-generation black family with isolated autosomal dominant Fanconi's syndrome. We performed genomewide linkage analysis, gene sequencing, biochemical and cell-biologic investigations of renal proximal tubular cells, studies in knockout mice, and functional evaluations of mitochondria. Urine was studied with the use of proton nuclear magnetic resonance (1H-NMR) spectroscopy.
RESULTS
We linked the phenotype of this family's Fanconi's syndrome to a single locus on chromosome 3q27, where a heterozygous missense mutation in EHHADH segregated with the disease. The p.E3K mutation created a new mitochondrial targeting motif in the N-terminal portion of EHHADH, an enzyme that is involved in peroxisomal oxidation of fatty acids and is expressed in the proximal tubule. Immunocytofluorescence studies showed mistargeting of the mutant EHHADH to mitochondria. Studies of proximal tubular cells revealed impaired mitochondrial oxidative phosphorylation and defects in the transport of fluids and a glucose analogue across the epithelium. 1H-NMR spectroscopy showed elevated levels of mitochondrial metabolites in urine from affected family members. Ehhadh knockout mice showed no abnormalities in renal tubular cells, a finding that indicates a dominant negative nature of the mutation rather than haploinsufficiency.
CONCLUSIONS
Mistargeting of peroxisomal EHHADH disrupts mitochondrial metabolism and leads to renal Fanconi's syndrome; this indicates a central role of mitochondria in proximal tubular function. The dominant negative effect of the mistargeted protein adds to the spectrum of monogenic mechanisms of Fanconi's syndrome. (Funded by the European Commission Seventh Framework Programme and others.
A Founder Mutation in EHD1 Presents with Tubular Proteinuria and Deafness
Background
The endocytic reabsorption of proteins in the proximal tubule requires a complex machinery and defects can lead to tubular proteinuria. The precise mechanisms of endocytosis and processing of receptors and cargo are incompletely understood. EHD1 belongs to a family of proteins presumably involved in the scission of intracellular vesicles and in ciliogenesis. However, the relevance of EHD1 in human tissues, in particular in the kidney, was unknown.
Methods
Genetic techniques were used in patients with tubular proteinuria and deafness to identify the disease-causing gene. Diagnostic and functional studies were performed in patients and disease models to investigate the pathophysiology.
Results
We identified six individuals (5â33 years) with proteinuria and a high-frequency hearing deficit associated with the homozygous missense variant c.1192C>T (p.R398W) in EHD1. Proteinuria (0.7â2.1 g/d) consisted predominantly of low molecular weight proteins, reflecting impaired renal proximal tubular endocytosis of filtered proteins. Ehd1 knockout and Ehd1R398W/R398W knockin mice also showed a high-frequency hearing deficit and impaired receptor-mediated endocytosis in proximal tubules, and a zebrafish model showed impaired ability to reabsorb low molecular weight dextran. Interestingly, ciliogenesis appeared unaffected in patients and mouse models. In silico structural analysis predicted a destabilizing effect of the R398W variant and possible inference with nucleotide binding leading to impaired EHD1 oligomerization and membrane remodeling ability.
Conclusions
A homozygous missense variant of EHD1 causes a previously unrecognized autosomal recessive disorder characterized by sensorineural deafness and tubular proteinuria. Recessive EHD1 variants should be considered in individuals with hearing impairment, especially if tubular proteinuria is noted
Glycine Amidinotransferase (GATM), Renal Fanconi Syndrome, and Kidney Failure
Background For many patients with kidney failure, the cause and underlying defect remain unknown. Here, we describe a novel mechanism of a genetic order characterized by renal Fanconi syndrome and kidney failure. Methods We clinically and genetically characterized members of five families with autosomal dominant renal Fanconi syndrome and kidney failure. We performed genome-wide linkage analysis, sequencing, and expression studies in kidney biopsy specimens and renal cells along with knockout mouse studies and evaluations of mitochondrial morphology and function. Structural studies examined the effects of recognized mutations. Results The renal disease in these patients resulted from monoallelic mutations in the gene encoding glycine amidinotransferase (GATM), a renal proximal tubular enzyme in the creatine biosynthetic pathway that is otherwise associated with a recessive disorder of creatine deficiency. In silico analysis showed that the particular GATM mutations, identified in 28 members of the five families, create an additional interaction interface within the GATM protein and likely cause the linear aggregation of GATM observed in patient biopsy specimens and cultured proximal tubule cells. GATMaggregates-containing mitochondria were elongated and associated with increased ROS production, activation of the NLRP3 inflammasome, enhanced expression of the profibrotic cytokine IL-18, and increased cell death. Conclusions In this novel genetic disorder, fully penetrant heterozygous missense mutations in GATM trigger intramitochondrial fibrillary deposition of GATM and lead to elongated and abnormal mitochondria. We speculate that this renal proximal tubular mitochondrial pathology initiates a response from the inflammasome, with subsequent development of kidney fibrosis