681 research outputs found

    Eating Oil

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    The food system is now even more based on cheap crude oil. Every time we eat, we are all essentially ‘eating oil’. Virtually all of the processes in the modern food system are now dependent upon this finite resource which is nearing its depletion phase. Moreover, at a time when we should be making massive cuts in the emissions of greenhouse gases into the atmosphere in order to reduce the threat posed by climate change, the food system is lengthening its supply chains and increasing emissions to the point where it is a significant contributor to global warming. The organic sector should be leading the development of a sustainable food system. Direct environmental and ecological impacts of agriculture ‘on the farm’ are certainly reduced in organic systems. However, global trade and distribution of organic products fritter away those benefits and undermine its leadership role. Not only is the contemporary food system inherently unsustainable, increasingly it is damaging the environment. A different approach - focussed on localization not globalisation - needs to be developed in order to ensure “food supply in a changing climate”

    Government accounting in the Global South: the design, implementation and use of global solutions for local needs

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    This chapter examines the impact of globalized accounting and economic reforms on the public sectors of the Global South, focusing particularly on the countries in Sub-Saharan Africa. Over the last three decades, people living in these countries have experienced debt crises, civil wars, coups and, on top of all that, externally imposed neoliberal economic reforms. Accounting has been an integral part of those imposed 'reforms'

    Quasar viscosity crisis

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    Recent observations of extreme variability in Active Galactic Nuclei have pushed standard viscous accretion disc models over an edge. "Extreme reprocessing" where an erratically variable central quasi-point source is entirely responsible for heating an otherwise cold and passive low-viscosity disc, may be the best route forward.Comment: For consistency with Nature policy, the version posted here is the text as submitted to Nature Astronomy in November 2017. The final version is available at the DOI below, and differs slightly in wording. The final version can be posted in six month

    EFRC Bulletin 77

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    EFRC's regular newletter covering policy, agricutlural research, policy and advisory wor

    Effect of 2-H and 18-O water isotopes in kinesin-1 gliding assay

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    We show here the effects of heavy-hydrogen water (^2^H~2~O) and heavy-oxygen water (H~2~^18^O) on the gliding speed of microtubules on kinesin-1 coated surfaces. Increased fractions of isotopic waters used in the motility solution decreased the gliding speed of microtubules by a maximum of 21% for heavy-hydrogen and 5% for heavy-oxygen water. We discuss possible interpretations of these results and the importance for future studies of water effects on kinesin and microtubules. We also discuss the implication for biomolecular devices incorporating molecular motors

    Speed effects in gliding motility assays due to surface passivation, water isotope, and osmotic stress.

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    The molecular motor kinesin-1, an ATPase, and the substrate it walks along, microtubules, are vital components of eukaryotic cells. Kinesin converts chemical energy to linear motion as its two motor domains step along microtubules in a process similar to how we walk. Cells create systems of microtubules that direct the motion of kinesin. This directed motion allows kinesin to transport various cargos inside cells.

During the stepping process, the kinesin motor domains bind and unbind from their binding sites on the microtubules. Binding and unbinding rates of biomolecules are highly dependent on hydration and exclusion of water from the binding interface. Osmotic stress will likely strongly affect the binding and unbinding rates for kinesin and thus offers a tool to specifically probe those steps. We will report the effects of different osmolytes on microtubule speed and other observables in the gliding motility assay.

Kinesin’s kinetic core cycle hydrolyzes ATP with the help of a water molecule. Any modification to the water molecules the kinesin is in will change how ATP hydrolyzes and will ultimately affect how kinesin moves along microtubules. We will report preliminary results showing how kinesin is affected when the solvent it is in is changed from light water to heavy water.
 
When used in a surface assay or in devices, the kinesin and microtubule system is also dependent on substrate passivation. Kinesin motor domains do not transport microtubules in the gliding motility assay if kinesin is added to a glass microscope slide that has not been functionalized. Functionalization of the glass slides and slips is typically performed with bovine milk proteins called caseins. Bovine casein is a globular protein that can be broken up into four constituents: αs1, αs2, β, and κ. Each casein constituent affects how kinesin adheres to the glass and ultimately the speed at which microtubules are observed to glide at. Building on the work of Verma et.al., we have found that each constituent individually produces different outcomes in gliding assays. We will present these findings and discuss implications they have for use of gliding assays to study kinesin and use of kinesin-microtubule system in microdevices. 

[1] Chaen, S, N Yamamoto, I Shirakawa, and H Sugi. 2001. Effect of deuterium oxide on actomyosin motility in vitro. _Biochimica et biophysica acta_ 1506, no. 3: 218-23. 
[2] Vivek Verma, William O Hancock, Jeffrey M Catchmark, "The role of casein in supporting the operation of surface bound kinesin," _J. Biol. Eng._ 2008; 2: 14.

Acknowledgements: This work was supported by the DTRA CB Basic Research Program under Grant No. HDTRA1-09-1-008.
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    Joint grad program builds skills, friendships

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    Biorenewable materials, biofuels and alternative clean technologies are gaining attention in the United States due to recent economic, political and scientific devel­ opments, but these issues have been seriously investigated for many years in Western Europe. A recent educational innovation jointly funded by the U.S. Department of Education\u27s Fund for the Improvement in Post Secondary Education (FIPSE), and the European Union\u27s Directorate for Education and Culture (DG EAC) has enabled the creation of the EU/U.S. Curriculum on Renewable Resources and Clean Technology program

    Accounting for Government in the Global South: do global solutions match local problems?

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    This paper examines the impact of globalised accounting and economic reforms on the public sectors of less developed countries. Our interest is in the international institutions that have been instrumental in introducing common, global remedies which appear to be based on theoretical understandings as opposed to experience of the effects of their interventions. A growing concern is being expressed about such interventions, but there is a sparcity of reports from the field. We argue that a re-think is required of type of the public sector financial management reforms which the international financial institutions and the national aid agencies have been promoting across the Global South for the last decade or so
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