The conundrum of conservation agriculture and livelihoods in Southern Africa

Low crop productivity, food insecurity, hunger and malnutrition; inadequate farming knowledge and skills, implements and inputs are characteristic of smallholder agriculture in Southern Africa. Many researchers argue that conservation agriculture can guarantee higher crop productivity, food security, improved livelihoods and environmental protection, better than the unsustainable traditional systems of slash and burn practices. In this paper, we present the results of a meta-analysis of over 40 academic publications to review conservation agriculture’s role in influencing desired livelihood outcomes in Southern Africa. We conclude that the effectiveness of conservation agriculture towards better livelihood outcomes in Southern Africa remains debatable, especially when supportive government policies are lacking

Chromosome organization in 4D: insights from C. elegans development

Eukaryotic genome organization is ordered and multilayered, from the nucleosome to chromosomal scales. These layers are not static during development, but are remodeled over time and between tissues. Thus, animal model studies with high spatiotemporal resolution are necessary to understand the various forms and functions of genome organization in vivo. In C. elegans, sequencing- and imaging-based advances have provided insight on how histone modifications, regulatory elements, and large-scale chromosome conformations are established and changed. Recent observations include unexpected physiological roles for topologically associating domains, different roles for the nuclear lamina at different chromatin scales, cell-type-specific enhancer and promoter regulatory grammars, and prevalent compartment variability in early development. Here, we summarize these and other recent findings in C. elegans, and suggest future avenues of research to enrich our in vivo knowledge of the forms and functions of nuclear organization

Wealth-related inequalities in adoption of drought-tolerant maize and conservation agriculture in Zimbabwe

© 2019, International Society for Plant Pathology and Springer Nature B.V. This paper concerns Drought-Tolerant Maize (DTM) and Conservation Agriculture (CA) practices that were introduced into smallholder maize-based farming systems in Zimbabwe to enhance the productivity of maize and food security under a changing climate. Although these technologies are technically appropriate, there are difficulties with their use by smallholder farmers of relatively low socio-economic status, as measured through ownership of farm or household assets and endowments. Thus, we sought to quantify and explain wealth-related inequalities in the adoption of DTM and CA in smallholder farming communities and discuss their implications for food security. The analysis used cross-sectional household-level data gathered from 601 smallholder farmers from four districts in Zimbabwe. We found evidence of a pro-rich distribution of inequalities in the adoption of DTM and CA that were mostly explained by differences in household wealth, access to agricultural extension services and size of farm land. No meaningful differences in DTM adoption disparities were found across districts. Significant gender differences were observed for CA, and meaningful differences by district were noted. Results suggest the need for decision makers to consider implementing policies that focus on the poorer segments of the farming society to alleviate differences in the adoption of such agricultural technologies. For example, subsidizing the uptake of improved maize varieties including DTM and prioritizing equitable land distribution, coupled with specialised extension services for the poor in a cereal-based CA farming system, could reduce the observed gap between rich and poor in the uptake of these innovations and consequently improve food security

Sensitivity of an image plate system in the XUV (60 eV < E < 900 eV)

Phosphor imaging plates (IPs) have been calibrated and proven useful for quantitative x-ray imaging in the 1 to over 1000 keV energy range. In this paper we report on calibration measurements made at XUV energies in the 60 to 900 eV energy range using beamline 6.3.2 at the Advanced Light Source at Lawrence Berkeley National Laboratory. We measured a sensitivity of ~25 plus or minus 15 counts/pJ over the stated energy range which is compatible with the sensitivity of Si photodiodes that are used for time-resolved measurements. Our measurements at 900 eV are consistent with the measurements made by Meadowcroft et al. at ~1 keV.Comment: 7 pages, 2 figure

Temporal Regulation of Foregut Development by HTZ-1/H2A.Z and PHA-4/FoxA

The histone variant H2A.Z is evolutionarily conserved and plays an essential role in mice, Drosophila, and Tetrahymena. The essential function of H2A.Z is unknown, with some studies suggesting a role in transcriptional repression and others in activation. Here we show that Caenorhabditis elegans HTZ-1/H2A.Z and the remodeling complex MYS-1/ESA1–SSL-1/SWR1 synergize with the FoxA transcription factor PHA-4 to coordinate temporal gene expression during foregut development. We observe dramatic genetic interactions between pha-4 and htz-1, mys-1, and ssl-1. A survey of transcription factors reveals that this interaction is specific, and thus pha-4 is acutely sensitive to reductions in these three proteins. Using a nuclear spot assay to visualize HTZ-1 in living embryos as organogenesis proceeds, we show that HTZ-1 is recruited to foregut promoters at the time of transcriptional onset, and this recruitment requires PHA-4. Loss of htz-1 by RNAi is lethal and leads to delayed expression of a subset of foregut genes. Thus, the effects of PHA-4 on temporal regulation can be explained in part by recruitment of HTZ-1 to target promoters. We suggest PHA-4 and HTZ-1 coordinate temporal gene expression by modulating the chromatin environment

A sapphire monolithic differential accelerometer as core sensor for gravity gradiometric geophysical instrumentation

Gradiometric gravimetry is a survey technique widely used in geological structure investigation. This work demonstrates the feasibility of a new class of low frequency accelerometers for geodynamics studies and space applications. We present the design features of a new low noise single-axis differential accelerometer; the sensor is suitable to be used in a Gravity Gradiometer (GG) system for land geophysical survey and gravity gradient measurements. A resolution of 1 Eötvös (1 Eö=10−9s−2) at one sample per second is achievable in a compact, lightweight (less than 2 kg) portable instrument, operating at room temperature. The basic components of the sensor are two identical rigidly connected accelerometers separated by a 15-cm baseline vector and the useful signal is extracted as the subtraction of the two outputs, by means of an interferometric microwave readout system. The structure will be engraved in a monocrystal of sapphire by means of Computer-Numerically-Controlled (CNC) ultrasonic machining: the material was chosen because of its unique mix of outstanding mechanical and dielectric properties

Why is it some households fall into poverty at the same time others are escaping poverty? Evidence from Kenya

Presents study carried out to evaluate how different households have fared over time in the communities. The aim of the study was to determine the proportions of households that Why is it some households fall into poverty at the same time others are escaping poverty? The study presents results from a study of poverty dynamics across Kenya using a participatory poverty assessment methodology known as the ‘Stages of Progress Methodology.’ This method is a relatively rapid, effective and participatory way to learn about poverty processes at both community and household levels. The approach generates very useful information for identifying the poor, and for understanding the factors that push people into and pull them out of poverty. Using this methodology, the typical stages through which people progress out of poverty were elicited for 71 Kenyan communities and 4773 households. The discussion of the different stages, and the order in which they occur, provoked lively debate among assembled villagers. The findings show that in virtually all 71 communities, house-holds progress out of poverty first by acquiring food, followed by obtaining adequate clothing, making improvements in their shelter, securing primary education for their children, starting small businesses. The paper presents the results of recent investigations, carried out specifically to gain knowledge about the reasons underlying poverty. Reasons for escape and reasons for descent operating in each livelihood region of Kenya were identified through a careful examination of poverty dynamics

Inflammation subverts hippocampal synaptic plasticity in experimental multiple sclerosis

Abnormal use-dependent synaptic plasticity is universally accepted as the main physiological correlate of memory deficits in neurodegenerative disorders. It is unclear whether synaptic plasticity deficits take place during neuroinflammatory diseases, such as multiple sclerosis (MS) and its mouse model, experimental autoimmune encephalomyelitis (EAE). In EAE mice, we found significant alterations of synaptic plasticity rules in the hippocampus. When compared to control mice, in fact, hippocampal long-term potentiation (LTP) induction was favored over long-term depression (LTD) in EAE, as shown by a significant rightward shift in the frequency-synaptic response function. Notably, LTP induction was also enhanced in hippocampal slices from control mice following interleukin-1β (IL-1β) perfusion, and both EAE and IL-1β inhibited GABAergic spontaneous inhibitory postsynaptic currents (sIPSC) without affecting glutamatergic transmission and AMPA/NMDA ratio. EAE was also associated with selective loss of GABAergic interneurons and with reduced gamma-frequency oscillations in the CA1 region of the hippocampus. Finally, we provided evidence that microglial activation in the EAE hippocampus was associated with IL-1β expression, and hippocampal slices from control mice incubated with activated microglia displayed alterations of GABAergic transmission similar to those seen in EAE brains, through a mechanism dependent on enhanced IL-1β signaling. These data may yield novel insights into the basis of cognitive deficits in EAE and possibly of MS