307 research outputs found

    The inner membrane complex through development of Toxoplasma gondii and Plasmodium

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    Plasmodium spp. and Toxoplasma gondii are important human and veterinary pathogens. These parasites possess an unusual double membrane structure located directly below the plasma membrane named the inner membrane complex (IMC). First identified in early electron micrograph studies, huge advances in genetic manipulation of the Apicomplexa have allowed the visualization of a dynamic, highly structured cellular compartment with important roles in maintaining the structure and motility of these parasites. This review summarizes recent advances in the field and highlights the changes the IMC undergoes during the complex life cycles of the Apicomplexa

    The Mobile Phone in the Diffusion of Knowledge for Institutional Quality in Sub-Saharan Africa

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    This study assesses the mobile phone in the diffusion of knowledge for better governance in Sub-Saharan Africa from 2000 to 2012. For this purpose we employ Generalised Method of Moments with forward orthogonal deviations. The empirical evidence is based on three complementary knowledge diffusion variables (innovation, internet penetration and educational quality) and 10 governance indicators that are bundled and unbundled. The following are the main findings. First, there is an unconditional positive effect of mobile phone penetration on good governance. Second, the net effects on political, economic, and institutional governances that are associated with the interaction of the mobile phone with knowledge diffusion variables are positive for the most part. Third, countries with low levels of governance are catching-up their counterparts with higher levels of governance. The above findings are broadly consistent with theoretical underpinnings on the relevance of mobile phones in mitigating bad governance in Africa. The evidence of some insignificant net effects and decreasing marginal impacts may be an indication that the mobile phone could also be employed to decrease government quality. Overall, this study has established net positive effects for the most part. Five rationales could elicit the positive net effects on good governance from the interaction between mobile phones and knowledge diffusion, among others, the knowledge variables enhance: reach, access, adoption, cost-effectiveness, and interaction. In a nut shell, the positive net effects are apparent because the knowledge diffusion variables complement mobile phones in reducing information asymmetry and monopoly that create conducive conditions for bad governance. The contribution of the findings to existing theories and justifications of the underlying positive net effects are discussed

    Aryl Functionalization as a Route to Band Gap Engineering in Single Layer Graphene Devices

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    Chemical functionalization is a promising route to band gap engineering of graphene. We chemically grafted nitrophenyl groups onto exfoliated single-layer graphene sheets in the form of substrate-supported or free-standing films. Our transport measurements demonstrate that non-suspended functionalized graphene behaves as a granular metal, with variable range hopping transport and a mobility gap ~ 0.1 eV at low temperature. For suspended graphene that allows functionalization on both surfaces, we demonstrate tuning of its electronic properties from a granular metal to a gapped semiconductor, in which charge transport occurs via thermal activation over a gap ~ 80 meV. This non-invasive and scalable functionalization technique paves the way for CMOS-compatible band gap engineering of graphene electronic devices

    25th RCOphth Congress, President's Session paper:25 years of progress in medical retina

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    The quarter century since the foundation of the Royal College of Ophthalmologists has coincided with immense change in the subspecialty of medical retina, which has moved from being the province of a few dedicated enthusiasts to being an integral, core part of ophthalmology in every eye department. In age-related macular degeneration, there has been a move away from targeted, destructive laser therapy, dependent on fluorescein angiography to intravitreal injection therapy of anti-growth factor agents, largely guided by optical coherence tomography. As a result of these changes, ophthalmologists have witnessed a marked improvement in visual outcomes for their patients with wet age-related macular degeneration (AMD), while at the same time developing and enacting entirely novel ways of delivering care. In the field of diabetic retinopathy, this period also saw advances in laser technology and a move away from highly destructive laser photocoagulation treatment to gentler retinal laser treatments. The introduction of intravitreal therapies, both steroids and anti-growth factor agents, has further advanced the treatment of diabetic macular oedema. This era has also seen in the United Kingdom the introduction of a coordinated national diabetic retinopathy screening programme, which offers an increasing hope that the burden of blindness from diabetic eye disease can be lessened. Exciting future advances in retinal imaging, genetics, and pharmacology will allow us to further improve outcomes for our patients and for ophthalmologists specialising in medical retina, the future looks very exciting but increasingly busy

    The Comparative Economics of Knowledge Economy in Africa: Policy Benchmarks, Syndromes and Implications

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    Sized-based indicators show depth-dependent change over time in the deep sea

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    Size-based indicators are well established as a management tool in shelf seas as they respond to changes in fishing pressure and describe important aspects of community function. In the deep sea, however, vital rates are much slower and body size relationships vary with depth, making it less clear how size-based indicators can be applied and whether they are appropriate for detecting changes through time. The deep-sea fish stocks of the North Atlantic underwent a period of exploitation followed by management and conservation action that relieved this pressure. We used data from a deep-water bottom trawl survey in the Rockall Trough, at depths of 300–2000 m, to test whether size-based indicators changed over a 16-year period, during which fishing pressure decreased. We applied four indicators to these data: mean body length, mean maximum length, large fish indicator (LFI) and the slope of the biomass spectrum. Patterns were analysed within four different depth bands. The LFI and slope of the biomass spectrum showed positive change over time, suggesting recovery from fishing pressure. This response was generally most apparent in the shallowest depth band, where most fishing activity has been distributed. Values of the LFI were much higher overall than in shelf seas, so the same reference points cannot be applied to all marine ecosystems. These findings imply that size-based indicators can be usefully applied to the deep sea and that they potentially track changes in fishing pressure in the medium term
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