Narratives from an Excursion to Grapesyard School in Korogocho Slum, Nairobi: Reflections and Perspectives on Education, Community Spirit and Resilience

In March 2016, a delegation of English instructors from Japanese universities attended an international conference in Nairobi, Kenya and visited a local school in the outlying slum neighborhood of Korogocho to observe students in their classrooms, visit homes and explore the local community. They also delivered donated laptop computers to help establish a digital textbook computer laboratory to enhance the children’s learning opportunities. This report is a compilation of narratives of the trip from the delegation and offers individual perspectives and reflections on education, resilience and the spirit of the school and surrounding community

GLOBAL SIMULATIONS OF PROTOPLANETARY DISKS WITH OHMIC RESISTIVITY AND AMBIPOLAR DIFFUSION

Protoplanetary disks are believed to accrete onto their central T Tauri star because of magnetic stresses. Recently published shearing box simulations indicate that Ohmic resistivity, ambipolar diffusion and the Hall effect all play important roles in disk evolution. In the presence of a vertical magnetic field, the disk remains laminar between 1-5au, and a magnetocentrifugal disk wind forms that provides an important mechanism for removing angular momentum. Questions remain, however, about the establishment of a true physical wind solution in the shearing box simulations because of the symmetries inherent in the local approximation. We present global MHD simulations of protoplanetary disks that include Ohmic resistivity and ambipolar diffusion, where the time-dependent gas-phase electron and ion fractions are computed under FUV and X-ray ionization with a simplified recombination chemistry. Our results show that the disk remains laminar, and that a physical wind solution arises naturally in global disk models. The wind is sufficiently efficient to explain the observed accretion rates. Furthermore, the ionization fraction at intermediate disk heights is large enough for magneto-rotational channel modes to grow and subsequently develop into belts of horizontal field. Depending on the ionization fraction, these can remain quasi-global, or break-up into discrete islands of coherent field polarity. The disk models we present here show a dramatic departure from our earlier models including Ohmic resistivity only. It will be important to examine how the Hall effect modifies the evolution, and to explore the influence this has on the observational appearance of such systems, and on planet formation and migration.Comment: 18 pages, 12 figures, accepted for publication in Ap

Histone Deacetylase Inhibitor Romidepsin Induces HIV Expression in CD4 T Cells from Patients on Suppressive Antiretroviral Therapy at Concentrations Achieved by Clinical Dosing

Persistent latent reservoir of replication-competent proviruses in memory CD4 T cells is a major obstacle to curing HIV infection. Pharmacological activation of HIV expression in latently infected cells is being explored as one of the strategies to deplete the latent HIV reservoir. In this study, we characterized the ability of romidepsin (RMD), a histone deacetylase inhibitor approved for the treatment of T-cell lymphomas, to activate the expression of latent HIV. In an in vitro T-cell model of HIV latency, RMD was the most potent inducer of HIV (EC50 = 4.5 nM) compared with vorinostat (VOR; EC50 = 3,950 nM) and other histone deacetylase (HDAC) inhibitors in clinical development including panobinostat (PNB; EC50 = 10 nM). The HIV induction potencies of RMD, VOR, and PNB paralleled their inhibitory activities against multiple human HDAC isoenzymes. In both resting and memory CD4 T cells isolated from HIV-infected patients on suppressive combination antiretroviral therapy (cART), a 4-hour exposure to 40 nM RMD induced a mean 6-fold increase in intracellular HIV RNA levels, whereas a 24-hour treatment with 1 μM VOR resulted in 2- to 3-fold increases. RMD-induced intracellular HIV RNA expression persisted for 48 hours and correlated with sustained inhibition of cell-associated HDAC activity. By comparison, the induction of HIV RNA by VOR and PNB was transient and diminished after 24 hours. RMD also increased levels of extracellular HIV RNA and virions from both memory and resting CD4 T-cell cultures. The activation of HIV expression was observed at RMD concentrations below the drug plasma levels achieved by doses used in patients treated for T-cell lymphomas. In conclusion, RMD induces HIV expression ex vivo at concentrations that can be achieved clinically, indicating that the drug may reactivate latent HIV in patients on suppressive cART

Predicting plant diversity patterns in Madagascar : understanding the effects of climate and land cover change in a biodiversity hotspot

Climate and land cover change are driving a major reorganization of terrestrial biotic communities in tropical ecosystems. In an effort to understand how biodiversity patterns in the tropics will respond to individual and combined effects of these two drivers of environmental change, we use species distribution models (SDMs) calibrated for recent climate and land cover variables and projected to future scenarios to predict changes in diversity patterns in Madagascar. We collected occurrence records for 828 plant genera and 2186 plant species. We developed three scenarios, (i.e., climate only, land cover only and combined climate-land cover) based on recent and future climate and land cover variables. We used this modelling framework to investigate how the impacts of changes to climate and land cover influenced biodiversity across ecoregions and elevation bands. There were large-scale climate- and land cover-driven changes in plant biodiversity across Madagascar, including both losses and gains in diversity. The sharpest declines in biodiversity were projected for the eastern escarpment and high elevation ecosystems. Sharp declines in diversity were driven by the combined climate-land cover scenarios; however, there were subtle, region-specific differences in model outputs for each scenario, where certain regions experienced relatively higher species loss under climate or land cover only models. We strongly caution that predicted future gains in plant diversity will depend on the development and maintenance of dispersal pathways that connect current and future suitable habitats. The forecast for Madagascar's plant diversity in the face of future environmental change is worrying: regional diversity will continue to decrease in response to the combined effects of climate and land cover change, with habitats such as ericoid thickets and eastern lowland and sub-humid forests particularly vulnerable into the future

Changes in species and genera richness across different zonal systems, showing the absolute changes in richness for (a, b) ecoregions found in Madagascar, (c, d) equal area elevation bands (each with an area of approximately 105 000 km², (e, f) equal interval elevation bands (at intervals of 390 m).

<p>The changes under each scenario are shown, with the climate change only scenario represented with the darkest grey, the land-cover change only scenario represented with the mid-grey and the combined scenario represented in the light grey. The mean is indicated with a solid horizontal line, the shaded areas represent ±1 standard deviation, whilst dashed lines extend to the minimum and maximum values.</p

Loss and gain in plant species and genera richness (measured on a pixel-by-pixel basis and normalized by area, km²) across different zonal systems for (a, b) ecoregions found in Madagascar, (c, d) equal area elevation bands (each with an area of approximately 105 000 km²), and (e, f) equal interval elevation bands (at intervals of 390 m).

<p>Changes under each scenario are shown as: climate only scenario (dark grey), land cover only scenario (mid-grey) and the combined scenario (light grey). The mean is indicated with a solid horizontal line, the shaded areas represent ±1 standard deviation, whilst dashed lines extend to the minimum and maximum values.</p

Site map showing the (a) ecoregions on which the analyses focused (excluding Mangroves) and (b) relief map of Madagascar, constructed using hill shade.

<p>Geographical Coordinate System (GCS) using the WGS1984 datum. Color figures available as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0122721#pone.0122721.s001" target="_blank">S1 Fig</a>.</p

Controlling Quantum Interference by Regulating Charge on the Bridging N Atom of Pyrrolodipyridine Molecular Junctions

Control of quantum interference features: molecular junctions incorporating pyrrolodipyridine-based molecular wires were fabricated by scanning probe methods. Quantum interference effects were introduced by employing meta-connected molecules, and modulated in magnitude by changing the substituent on the pyrrolic N. Dramatic changes in molecular conductance and DFT transport calculations demonstrate the storng effect that small changes in electronic density can have on the overall conductance of a molecular wire