A Page and Its Politics: Situating Kullinā Khālid Saʿīd in Egypt’s Ideological Landscape at the Time of Revolution

In discussions concerning the importance of social media in the 25January revolution, a central role is given to the "Kullinā Khālid Saʿīd" [We’re all Khaled Said] Facebook page. Using an advanced data collection and extraction application called Netvizz, a research team consisting of Arabists and Media studies specialists has collected and analysed all of the posts and comments exchanged through the page. This data set allows for a systematic analysis of the page. This article offers an outline of the ideological nature of "Kullinā Khālid Saʿīd", with particular emphasis on the "revolutionary" period between 1 January - 11 February 2011. It argues that the page shows no evidence of political bias in the sense of explicit favoring of a political group. Rather, the page constituted a community of users who abstained from using politically factional language. Reflecting the mood and concerns of the revolution’s grassroots masses, it clearly illustrates the disinclination to engage with formal politics

Watermelon production on stored rainwater in Sahelian sandy soils

Watermelon [Citrullus lanatus (Thumb) Matsun and Nakai ] is an important cash crop in West Africa where it is cultivated under rainfed conditions. The objective of this work was to identify best cultural practices for production of watermelons in the Sahel on stored rainwater in acid sandy soils. The experiments were carried out at the ICRISAT Sadore research center in Niger during two consecutive dry seasons, 2003 - 2004 and 2004 - 2005. Three soil management treatments were applied: microcatchments (also called half-moons), planting pits (also called zaï) and sowing on flat land. Each of these three treatments came with and without a soil amendment comprising of 500 g of manure mixed with 24 g of a complete (NPK) fertilizer (15-15-15) individually applied to each planting hill. Two watermelon cultivars were tested: ‘Malali’ and ‘Kaolack’. In each of the two years the experiments were sown on the 1st and on the 21st of September. Fruit and biomass yield, fruit Total Soluble Solids (TSS), days to fruiting and harvesting were determined. Soil fertility, root development and other physiological parameters were monitored to explain some of the differences between treatments. Soil amendments increased marketable yields from 1.3 to 3.5 tons ha-1 on average. Marketable yields at the first planting date were double the yields of the second planting date (3.2 vs. 1.6 tons ha-1). Yield differences were due to changes in fruit number not in fruit weight. Deep placement of soil amendments resulted in significant root development in deeper soil layers. Highest watermelon yields were achieved when sowing the Malali cultivar in amended planting pits on September 1st giving a yield of 8.2 tons ha-1

Hypersensitive cell death in plants : its mechanisms and role in plant defense against pathogens

This review is a recent update in the understanding of the hypersensitive response (HR) of plants with special consideration to the physiological and biochemical determinants in different model systems. Hypersensitive response is reviewed as a form of programmed cell death (PCD) representing one of the mechanisms of plant defence against diseases. Major signalling pathways and molecules that accompany the HR, such as proteolytic cascades, oxidative events and ethylene that are supposed to play a key role in the plant¿s cell death machinery are discussed. Special attention is paid to the HR in fruit species. Studies on plant PCD are shown to provide a clue to better understanding disease resistance processes in plants and to establish the evolutionary aspects of PCD similarities through animal and plant kingdoms

The economics of low pressure drip irrigation and hand watering for vegetable production in the Sahel

Low pressure drip irrigation is being promoted in Sub Saharan Africa as an alternative to traditional methods of small scale irrigation of vegetables. The African Market Garden (AMG) is a horticultural production system for smallholders based on low-pressure drip irrigation combined with an improved crop management package. The agronomic and economic performance of the AMG is compared to two gardens irrigated manually with watering cans. One of these gardens is managed according to the same improved crop management package as in the AMG, this treatment is called Improved Management (IM). The other garden is managed according to common practices of vegetable producers in the area, this treatment is called the Farmer Practice (FP). Crop productivity, labor and water use were monitored for two vegetable species (okra and eggplants). The experiment was performed on-station in Niger on three adjacent 500 m2 plots in a sandy acid soil. It was found that improved crop management practices greatly enhance crop productivity over traditional methods at comparable production costs. The AMG gave higher crop yields and higher returns to investment than the treatments irrigated with watering cans. Labor accounts for up to 45% of the production cost in vegetable gardens irrigated by hand, where 80% of the producer time is spent on irrigation. The total labor requirement for the drip irrigated AMG was on average 1.1 man hours per day against 4.7 man hours per day for the Farmers Practice on a 500 m2 garden. Returns on labor are at least double for the AMG against the other treatments. The returns on land from eggplant were found to be US$1.7, 0.8 and 0.1 per m2 for the AMG, IM and FP respectively. The returns on water for the cultivation of eggplant are around US$ 2 per m3 in the AMG, against US$ 0.1 in the Farmers Practice. This experiment showed the strong positive impact of drip irrigation and improved crop management practices on profits at minimal environmental costs, indicating that transformation of existing practices poses a considerable potential towards sustainable agricultural developmen

Quantum interference enhances the performance of single-molecule transistors.

Quantum effects in nanoscale electronic devices promise to lead to new types of functionality not achievable using classical electronic components. However, quantum behaviour also presents an unresolved challenge facing electronics at the few-nanometre scale: resistive channels start leaking owing to quantum tunnelling. This affects the performance of nanoscale transistors, with direct source-drain tunnelling degrading switching ratios and subthreshold swings, and ultimately limiting operating frequency due to increased static power dissipation. The usual strategy to mitigate quantum effects has been to increase device complexity, but theory shows that if quantum effects can be exploited in molecular-scale electronics, this could provide a route to lower energy consumption and boost device performance. Here we demonstrate these effects experimentally, showing how the performance of molecular transistors is improved when the resistive channel contains two destructively interfering waves. We use a zinc-porphyrin coupled to graphene electrodes in a three-terminal transistor to demonstrate a >104 conductance-switching ratio, a subthreshold swing at the thermionic limit, a >7 kHz operating frequency and stability over >105 cycles. We fully map the anti-resonance interference features in conductance, reproduce the behaviour by density functional theory calculations and trace back the high performance to the coupling between molecular orbitals and graphene edge states. These results demonstrate how the quantum nature of electron transmission at the nanoscale can enhance, rather than degrade, device performance, and highlight directions for future development of miniaturized electronics

Mesoproterozoic surface oxygenation accompanied major sedimentary manganese deposition at 1.4 and 1.1 Ga

This research was funded by the Australian Science and Industry Endowment Fund (SIEF) as part of The Distal Footprints of Giant Ore Systems: UNCOVER Australia Project (RP04-063)—Capricorn Distal Footprints. EAS also thanks the donors of The American Chemical Society Petroleum Research Fund for partial support of this research (61017-ND2).Peer reviewedPublisher PD

Quantum Interference Enhances the Performance of Single-Molecule Transistors

An unresolved challenge facing electronics at a few-nm scale is that resistive channels start leaking due to quantum tunneling. This affects the performance of nanoscale transistors, with single-molecule devices displaying particularly low switching ratios and operating frequencies, combined with large subthreshold swings.1 The usual strategy to mitigate quantum effects has been to increase device complexity, but theory shows that if quantum effects are exploited correctly, they can simultaneously lower energy consumption and boost device performance.2-6 Here, we demonstrate experimentally how the performance of molecular transistors can be improved when the resistive channel contains two destructively-interfering waves. We use a zinc-porphyrin coupled to graphene electrodes in a three-terminal transistor device to demonstrate a >104 conductance-switching ratio, a subthreshold swing at the thermionic limit, a > 7 kHz operating frequency, and stability over >105 cycles. This performance is competitive with the best nanoelectronic transistors. We fully map the antiresonance interference features in conductance, reproduce the behaviour by density functional theory calculations, and trace back this high performance to the coupling between molecular orbitals and graphene edge states. These results demonstrate how the quantum nature of electron transmission at the nanoscale can enhance, rather than degrade, device performance, and highlight directions for future development of miniaturised electronics.Comment: 11 pages, 4 figure

Efficacy and safety of rozanolixizumab in moderate to severe generalized myasthenia gravis : a phase 2 randomized control trial

OBJECTIVE: To explore the clinical efficacy and safety of subcutaneous (SC) rozanolixizumab, an anti-neonatal Fc receptor humanized monoclonal antibody, in patients with generalized myasthenia gravis (gMG). METHODS: In this phase 2a, randomized, double-blind, placebo-controlled, 2-period, multicenter trial (NCT03052751), patients were randomized (1:1) in period 1 (days 1-29) to 3 once-weekly (Q1W) SC infusions of rozanolixizumab 7 mg/kg or placebo. In period 2 (days 29-43), patients were re-randomized to either rozanolixizumab 7 mg/kg or 4 mg/kg (3 Q1W SC infusions), followed by an observation period (days 44-99). Primary endpoint was change from baseline to day 29 in Quantitative Myasthenia Gravis (QMG) score. Secondary endpoints were change from baseline to day 29 in MG-Activities of Daily Living (MG-ADL) and MG-Composite (MGC) scores and safety. RESULTS: Forty-three patients were randomized (rozanolixizumab 21, placebo 22 [period 1]). Least squares (LS) mean change from baseline to day 29 for rozanolixizumab vs placebo was as follows: QMG (LS mean -1.8 vs -1.2, difference -0.7, 95% upper confidence limit [UCL] 0.8; p = 0.221; not statistically significant), MG-ADL (LS mean -1.8 vs -0.4, difference -1.4, 95% UCL -0.4), and MGC (LS mean -3.1 vs -1.2, difference -1.8, 95% UCL 0.4) scores. Efficacy measures continued to improve with rozanolixizumab 7 mg/kg in period 2. The most common adverse event in period 1 was headache (rozanolixizumab 57%, placebo 14%). CONCLUSION: Whereas change from baseline in QMG was not statistically significant, the data overall suggest rozanolixizumab may provide clinical benefit in patients with gMG and was generally well tolerated. Phase 3 evaluation is ongoing (NCT03971422). CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with gMG, rozanolixizumab is well-tolerated, but did not significantly improve QMG score

The Dryland Eco-Farm: A Potential Solution to the Main Constraints of Rain-Fed Agriculture in the Semi-Arid Tropics of Africa

This chapter presents the results of studies on a production system called Dryland Eco-Farm (DEF) that addresses a range of constraints to agricultural productivity in dryland Africa. It combines the use of live hedges and alleys of Acacia colei, “demi-lunes” in which are planted domesticated Ziziphus mauritiania. Annual crops like pearl millet (Pennisetum glaucum (L.) R.Br.), cowpeas and roselle (Hibiscus sabdariffa) are planted in rotation. This trial tests the effect of the system on (1) soil erosion control, soil fertility and water use efficiency, (2) crop yield and biomass production, and (3) improving income generation and diversification. Average pearl millet yields in the DEF were twice the control (880 vs. 430 kg ha–1) when no mineral fertilizer was applied. With the application of NPK, millet yields were almost similar under both conditions (950 vs. 780 kg ha–1). Cowpea yields were on average seven times higher than the control without NPK (1,400 vs. 200 kg ha–1 total biomass) and three times with NPK (1,850 vs. 650 kg ha–1 total biomass). Roselle yield increased four times on average without NPK (205 vs. 60 kg ha–1 calices yield) and two times with NPK (234 vs. 114 kg ha–1). Therefore, the system has the potential to produce yield response similar to that of the recommended rate of 100 kg of the 15-15-15 fertilizer per ha. The return to land is estimated at US 224 for the DEF compared to US224fortheDEFcomparedtoUS77 for the traditional millet–cowpea system. This system has the potential to improve productivity and rural livelihood in the drylands of Africa while sustaining the natural resources base