Key drivers of India’s African engagement

Daniel Large explains why Indian government and businesses are increasingly prioritising engagement with different parts of Africa. This post is an excerpt from “India’s African Engagement”, a chapter in the recent LSE IDEAS report on Emerging Powers in Africa. Click here for all India At LSE coverage of India-Africa ties

The limits of Modi-fying India’s Africa engagement

Last month’s India-Africa Forum and Summit saw African leaders welcomed with unprecedented levels of ceremony and political theatre. But Daniel Large writes that underneath new branding were old questions about how what was witnessed in Delhi in October will be followed through on in substantive ways, and the extent to which these will catalyse relations beyond political level

China’s Sudan engagement: changing Northern and Southern political trajectories in peace and war

China has developed a more consequential role in Sudan over the past two decades, during which it has become bound up in the combination of enduring violent internal instability and protracted external adversity that has characterized the politics of the central state since the 1989 Islamist revolution. Two inter-related political trajectories of China’s Sudan engagement are examined here. The first concerns Beijing’s relations with the ruling National Congress party in incorporating China into its domestic politics and foreign relations amidst war in Darfur, to which Beijing has responded through a more engaged political role. The second confronts the practical limitations of China’s sovereignty doctrine and exclusive reliance upon relations with the central state. Following the peace agreement of 2005 that ended the North–South war, and motivated by political imperatives linked to investment protection concerns, China has developed new relations with the semi-autonomous Government of Southern Sudan, thus seeking to position itself to navigate Sudan’s uncertain political future

Does pyrite act as an important host for molybdenum in modern and ancient euxinic sediments?

Molybdenum (Mo) is a popular paleoproxy for tracking the spatiotemporal pattern of euxinic (anoxic and sulfidic) conditions in the ancient ocean, yet surprisingly little is known about the processes leading to its fixation under sulfidic conditions. Pyrite has been proposed to be the main host phase for Mo sequestration. To clarify the role played by pyrite, and thus to refine the utility of this paleoproxy, modern and ancient samples from six different study sites were analyzed, all representing euxinic conditions, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Although pyrite often shows substantial enrichments relative to average crust and even matrix samples of similar size, our results show that most of the Mo in euxinic muds and shales is found in the non-pyrite matrix (80–100%) and not in the pyrite grains (0–20%)—simply because the volume of matrix dominates the bulk sediments/rocks. A relationship between the percent of Mo hosted by pyrite and the sulfur isotope composition of that pyrite is observed and can be linked to post-depositional alteration. Specifically, the oldest, typically most altered samples, show the highest δ^(34)S values because of limited sulfate availability at the time of their formation in the early ocean. In these old samples, the relatively small amount of Mo sequestered initially within pyrite is more likely to have been released to the matrix during the strong recrystallization overprints that these rocks have disproportionately suffered. Despite the universal importance of appreciable H_2S availability during Mo uptake, we conclude that pyrite should be viewed as a nontrivial sink for Mo but clearly not the primary host in most euxinic shales and rather suggest that other burial pathways should be emphasized in future studies of the mechanisms of Mo sequestration in such settings

Finding New Cell Wall Regulatory Genes in Populus trichocarpa Using Multiple Lines of Evidence.

Understanding the regulatory network controlling cell wall biosynthesis is of great interest in Populus trichocarpa, both because of its status as a model woody perennial and its importance for lignocellulosic products. We searched for genes with putatively unknown roles in regulating cell wall biosynthesis using an extended network-based Lines of Evidence (LOE) pipeline to combine multiple omics data sets in P. trichocarpa, including gene coexpression, gene comethylation, population level pairwise SNP correlations, and two distinct SNP-metabolite Genome Wide Association Study (GWAS) layers. By incorporating validation, ranking, and filtering approaches we produced a list of nine high priority gene candidates for involvement in the regulation of cell wall biosynthesis. We subsequently performed a detailed investigation of candidate gene GROWTH-REGULATING FACTOR 9 (PtGRF9). To investigate the role of PtGRF9 in regulating cell wall biosynthesis, we assessed the genome-wide connections of PtGRF9 and a paralog across data layers with functional enrichment analyses, predictive transcription factor binding site analysis, and an independent comparison to eQTN data. Our findings indicate that PtGRF9 likely affects the cell wall by directly repressing genes involved in cell wall biosynthesis, such as PtCCoAOMT and PtMYB.41, and indirectly by regulating homeobox genes. Furthermore, evidence suggests that PtGRF9 paralogs may act as transcriptional co-regulators that direct the global energy usage of the plant. Using our extended pipeline, we show multiple lines of evidence implicating the involvement of these genes in cell wall regulatory functions and demonstrate the value of this method for prioritizing candidate genes for experimental validation

Comparative Analysis of the Frequency and Distribution of Stem and Progenitor Cells in the Adult Mouse Brain

cells (NSCs) and progenitor cells, but it cannot discriminate between these two populations. Given two assays have purported to overcome this shortfall, we performed a comparative analysis of the distribution and frequency of NSCs and progenitor cells detected in 400 m coronal segments along the ventricular neuraxis of the adult mouse brain using the neurosphere assay, the neural colony forming cell assay (N-CFCA), and label-retaining cell (LRC) approach. We observed a large variation in the number of progenitor/stem cells detected in serial sections along the neuraxis, with the number of neurosphereforming cells detected in individual 400 m sections varying from a minimum of eight to a maximum of 891 depending upon the rostral-caudal coordinate assayed. Moreover, the greatest variability occurred in the rostral portion of the lateral ventricles, thereby explaining the large variation in neurosphere frequency previously reported. Whereas the overall number of neurospheres (3730 276) or colonies (4275 124) we detected along the neuraxis did not differ significantly, LRC numbers were significantly reduced (1186 188, 7 month chase) in comparison to both total colonies and neurospheres. Moreover, approximately two orders of magnitude fewer NSC-derived colonies (50 10) were detected using the N-CFCA as compared to LRCs. Given only 5% of the LRCs are cycling (BrdU/Ki-67) or competent to divide (BrdU/Mcm-2), and proliferate upon transfer to culture, it is unclear whether this technique selectively detects endogenous NSCs. Overall, caution should be taken with the interpretation and employment of all these techniques

The New Generation Atlas of Quasar Spectral Energy Distributions from Radio to X-rays

We have produced the next generation of quasar spectral energy distributions (SEDs), essentially updating the work of Elvis et al. (1994) by using high-quality data obtained with several space and ground-based telescopes, including NASA's Great Observatories. We present an atlas of SEDs of 85 optically bright, non-blazar quasars over the electromagnetic spectrum from radio to X-rays. The heterogeneous sample includes 27 radio-quiet and 58 radio-loud quasars. Most objects have quasi-simultaneous ultraviolet-optical spectroscopic data, supplemented with some far-ultraviolet spectra, and more than half also have Spitzer mid-infrared IRS spectra. The X-ray spectral parameters are collected from the literature where available. The radio, far-infrared, and near-infrared photometric data are also obtained from either the literature or new observations. We construct composite spectral energy distributions for radio-loud and radio-quiet objects and compare these to those of Elvis et al., finding that ours have similar overall shapes, but our improved spectral resolution reveals more detailed features, especially in the mid and near-infrared.Comment: 46 pages, 10 figures, 10 tables, Accepted by ApJS. Composite SED data files for radio-loud and radio-quiet quasars (rlmsedMR.txt, rqmsedMR.txt) are included in the source (Other formats -> Source). Supplemental figures are not include

Suppression-Induced Forgetting on a Free-Association Test

The repeated suppression of thoughts in response to cues for their expression leads to forgetting on a subsequent test of cued recall (Anderson & Green, 2001). We extended this effect by using homograph cues and presenting them for free association following suppression practice. Cue-target pairs were first learned under integrating imagery instructions; then in the think/no-think phase students practiced suppressing thoughts connected to some homograph cues, with or without the assistance of thought substitutes that changed their meaning. Below-baseline forgetting on the subsequent free-association test was found in the production of suppressed targets. Following aided suppression, this effect was also obtained in the production of other responses denoting the target-related meaning of the homograph cues. Discussion emphasizes the ecological value of the test; rarely do people deliberately attempt recall of unwanted thoughts

Spatial and seasonal variability of the air-sea equilibration timescale of carbon dioxide

The exchange of carbon dioxide between the ocean and the atmosphere tends to bring waters within the mixed layer toward equilibrium by reducing the partial pressure gradient across the air-water interface. However, the equilibration process is not instantaneous; in general, there is a lag between forcing and response. The timescale of air-sea equilibration depends on several factors involving the depth of the mixed layer, wind speed, and carbonate chemistry. We use a suite of observational data sets to generate climatological and seasonal composite maps of the air-sea equilibration timescale. The relaxation timescale exhibits considerable spatial and seasonal variations that are largely set by changes in mixed layer depth and wind speed. The net effect is dominated by the mixed layer depth; the gas exchange velocity and carbonate chemistry parameters only provide partial compensation. Broadly speaking, the adjustment timescale tends to increase with latitude. We compare the observationally derived air-sea gas exchange timescale with a model-derived surface residence time and a data-derived horizontal transport timescale, which allows us to define two nondimensional metrics of equilibration efficiency. These parameters highlight the tropics, subtropics, and northern North Atlantic as regions of inefficient air-sea equilibration where carbon anomalies are relatively likely to persist. The efficiency parameters presented here can serve as simple tools for understanding the large-scale persistence of air-sea disequilibrium of CO2 in both observations and models

Collective dynamics support group drumming, reduce variability, and stabilize tempo drift

Humans are social animals who engage in a variety of collective activities requiring coordinated action. Among these, music is a defining and ancient aspect of human sociality. Human social interaction has largely been addressed in dyadic paradigms, and it is yet to be determined whether the ensuing conclusions generalize to larger groups. Studied more extensively in non-human animal behavior, the presence of multiple agents engaged in the same task space creates different constraints and possibilities than in simpler dyadic interactions. We addressed whether collective dynamics play a role in human circle drumming. The task was to synchronize in a group with an initial reference pattern and then maintain synchronization after it was muted. We varied the number of drummers from solo to dyad, quartet, and octet. The observed lower variability, lack of speeding up, smoother individual dynamics, and leader-less inter-personal coordination indicated that stability increased as group size increased, a sort of temporal wisdom of crowds. We propose a hybrid continuous-discrete Kuramoto model for emergent group synchronization with a pulse-based coupling that exhibits a mean field positive feedback loop. This research suggests that collective phenomena are among the factors that play a role in social cognition