Performance of Reinforced Concrete Structures Subjected to Earthquake Motions

Two simplified methods for estimating the performance of reinforced concrete structures subjected to earthquake motions were evaluated. Both the Flat-Rate and Target Period methods characterize the expected level of performance in terms of the maximum estimated drift for a given intensity of ground motion. Drift estimates using the Flat-Rate method are based on the area of structural members, the total floor area of the structure, and the peak ground acceleration as a measure of earthquake intensity. The main parameters for the Target Period method are the initial period of the structures and the peak ground acceleration. The applicability of these methods to assess the expected level of performance of existing structures was investigated using experimental data. Drift values calculated with the Flat-Rate and Target Period methods were compared with measurements obtained from earthquake simulator tests performed on reduced-scale models of reinforced concrete structures. Results indicate that both methods provided an adequate assessment of performance

Smallholder Participation in Agricultural Value Chains: Comparative Evidence from Three Continents

Supermarkets, specialized wholesalers, and processors and agro-exporters’ agricultural value chains have begun to transform the marketing channels into which smallholder farmers sell produce in low-income economies. We develop a conceptual framework through which to study contracting between smallholders and a commodity-processing firm. We then conduct an empirical meta-analysis of agricultural value chains in five countries across three continents (Ghana, India, Madagascar, Mozambique, and Nicaragua). We document patterns of participation, the welfare gains associated with participation, reasons for non-participation, the significant extent of contract non-compliance, and the considerable dynamism of these value chains, as farmers and firms enter and exit frequently.

Smallholder Participation in Agricultural Value Chains: Comparative Evidence from Three Continents

Supermarkets, specialized wholesalers, and processors and agro-exporters’ agricultural value chains have begun to transform the marketing channels into which smallholder farmers sell produce in low-income economies. We develop a conceptual framework through which to study contracting between smallholders and a commodity-processing firm. We then conduct an empirical meta-analysis of agricultural value chains in five countries across three continents (Ghana, India, Madagascar, Mozambique, and Nicaragua). We document patterns of participation, the welfare gains associated with participation, reasons for non-participation, the significant extent of contract non-compliance, and the considerable dynamism of these value chains, as farmers and firms enter and exit frequently.Agricultural Value Chains, Contract Farming, Africa, Asia, Latin America

Intercomparison of three morphodynamic models for the Lower Yellow River

River morphodynamics and sediment transportRiver morphology and morphodynamic

High interindividual variability in dose-dependent reduction in speed of movement after exposing C. elegans to shock waves

In blast-related mild traumatic brain injury (br-mTBI) little is known about the connections between initial trauma and expression of individual clinical symptoms. Partly due to limitations of current in vitro and in vivo models of br-mTBI, reliable prediction of individual short-and long-term symptoms based on known blast input has not yet been possible. Here we demonstrate a dose-dependent effect of shock wave exposure on C. elegans using shock waves that share physical characteristics with those hypothesized to induce br-mTBI in humans. Increased exposure to shock waves resulted in decreased mean speed of movement while increasing the proportion of worms rendered paralyzed. Recovery of these two behavioral symptoms was observed during increasing post-traumatic waiting periods. Although effects were observed on a population-wide basis, large interindividual variability was present between organisms exposed to the same highly controlled conditions. Reduction of cavitation by exposing worms to shock waves in polyvinyl alcohol resulted in reduced effect, implicating primary blast effects as damaging components in shock wave induced trauma. Growing worms on NGM agar plates led to the same general results in initial shock wave effect in a standard medium, namely dose-dependence and high interindividual variability, as raising worms in liquid cultures. Taken together, these data indicate that reliable prediction of individual clinical symptoms based on known blast input as well as drawing conclusions on blast input from individual clinical symptoms is not feasible in br-mTBI

TGF-β-induced growth inhibition in B-cell lymphoma correlates with Smad1/5 signalling and constitutively active p38 MAPK

<p>Abstract</p> <p>Background</p> <p>Cytokines of the transforming growth factor β (TGF-β) superfamily exert effects on proliferation, apoptosis and differentiation in various cell types. Cancer cells frequently acquire resistance to the anti-proliferative signals of TGF-β, which can be due to mutations in proteins of the signalling cascade. We compared the TGF-β-related signalling properties in B-cell lymphoma cell lines that were sensitive or resistant to TGF-β-induced anti-proliferative effects.</p> <p>Results</p> <p>TGF-β sensitive cell lines expressed higher cell surface levels of the activin receptor-like kinase 5 (Alk-5), a TGF-β receptor type 1. The expression levels of the other TGF-β and bone morphogenetic protein receptors were comparable in the different cell lines. TGF-β-induced phosphorylation of Smad2 was similar in TGF-β sensitive and resistant cell lines. In contrast, activation of Smad1/5 was restricted to cells that were sensitive to growth inhibition by TGF-β. Moreover, with activin A we detected limited anti-proliferative effects, strong phosphorylation of Smad2, but no Smad1/5 phosphorylation. Up-regulation of the TGF-β target genes Id1 and Pai-1 was identified in the TGF-β sensitive cell lines. Constitutive phosphorylation of MAPK p38 was restricted to the TGF-β sensitive cell lines. Inhibition of p38 MAPK led to reduced sensitivity to TGF-β.</p> <p>Conclusions</p> <p>We suggest that phosphorylation of Smad1/5 is important for the anti-proliferative effects of TGF-β in B-cell lymphoma. Alk-5 was highly expressed in the sensitive cell lines, and might be important for signalling through Smad1/5. Our results indicate a role for p38 MAPK in the regulation of TGF-β-induced anti-proliferative effects.</p

Climatic trends, risk perceptions and coping strategies of smallholder farmers in rural Uganda

Smallholder farmers in Uganda face a wide range of agricultural production risks, with climate change and variability presenting new risks and vulnerabilities. Climate related risks such as prolonged dry seasons have become more frequent and intense with negative impacts on agricultural livelihoods and food security. This paper assesses farmers’ perceptions of climate change and variability and analyses historical trends in temperature and rainfall in two rural districts of Uganda in order to determine the major climate-related risks affecting crop and livestock production and to identify existing innovative strategies for coping with and adapting to climate-related risks, with potential for up-scaling in rural districts. The traditional coping strategies that have been developed by these communities overtime provide a foundation for designing effective adaptation strategies. Drought, disease and pest epidemics, decreasing water sources, lack of pasture, bush fires, hailstorms, changes in crop flowering and fruiting times were the major climate-related risks reported across the two districts. Farmers use a wide range of agricultural technologies and strategies to cope with climate change and climate variability. Mulching, intercropping and planting of food security crops were among the most common practices used. Other strategies included water harvesting for domestic consumption, other soil and water conservation technologies and on-farm diversification. Farmers often use a combination of these technologies and practices to enhance agricultural productivity. The average maximum temperatures increased across the two districts. Trends in average annual rainfall showed mixed results with a general decline in one district and a relatively stable trend in the other district. Perceived changes in climate included erratic rainfall onset and cessation, which were either early or late, poor seasonal distribution of rainfall and little rainfall. Farmers also reported variations in temperatures. Farmers’ perception of changing rainfall characteristics and increasing temperatures were consistent with the observed historical climatic trends from meteorological data

Antibody Validation and Dual IHC Staining of Glioblastoma Multiforme to Isolate Microglia Cells in Glial Cell Population for Biomarker Identification

https://openworks.mdanderson.org/sumexp23/1068/thumbnail.jp