148 research outputs found
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Mary Anna opened the door and saw her man. Her man was a hobo, looking for a bite to eat and possibly a pie which had been set on some ledge to cool.
Rambling Joe looked at the little girl and in his most polite manner, doffed his hat and said, Little girl, I wonder if you would ask your ma if she could spare a man a bite to eat.
My mother isn\u27t here, Mary Anna replied, and puffing up with importance said, if you will come in; maybe I can find something.
Mary Anna had just come bark from a revival meeting at her church. She had decided that her career was to be a missionary and here was a poor lonesome,
Sit down here, please, and I\u27ll make you some coffee. Daddy says I make very good coffee and Mother likes it, too. And Tom, he\u27s my brother, says it ain\u27t- she hastily corrected herself, isn\u27t much good. But you know boys.
Taking his manners out and dusting them off a bit, Joe said, I\u27m sure it will be fine
A Theoretical Study of Brownian Motors with Self-Induced Temperature Gradients
Brownian motors surmount energy barriers by absorbing and emitting heat to and from their local environment. In most theoretical treatments, the temperature gradients created in these heat exchanges are assumed to dissipate instantaneously. Here we relax this assumption to consider the case where Brownian dynamics can lead to self-induced temperature gradients in the local environment. We explore self-induced temperature gradients by considering an explicit equation of motion for the local temperature field. The equation of motion for the temperature contains a heat source term arising from the Brownian dynamics of the motor. In the same way that externally-imposed temperature gradients can cause directed motion, these self-induced gradients effect the Brownian dynamics of the system. The result is a two-way coupling between the local environment and the Brownian motor. We explore the resulting dynamics and thermodynamics of these novel coupled systems both in the steady state and in the dynamical state. We develop two numerical methods for solving the resulting equations of motion, both methods exploit the physical structure of our model. We check that our numerical methods converge to an analytical solution when available. We also check that the numerical methods converge as the discretization size is reduced. We consider self-induced temperature gradients on potentials that are relevant to Brownian motors. In particular, we show that self-induced temperature gradients can reduce barrier crossing rates in both one and two dimensions. We also implement heat engines and heat pumps based on temperature gradients induced by a Brownian motor on a non-equilibrium potential
Mitochondrial Ca²⁺ Uniporter haploinsufficiency enhances long-term potentiation at hippocampal mossy fibre synapses
Long-term changes in synaptic strength form the basis of learning and memory. These changes rely upon energy demanding mechanisms which are regulated by local Ca2+ signaling. Mitochondria are optimised for providing energy and buffering Ca2+. However, our understanding of the role of mitochondria in regulating synaptic plasticity is incomplete. Here we have used optical and electrophysiological techniques in cultured hippocampal neurons and ex vivo hippocampal slices from mice with haploinsufficiency of the mitochondrial Ca2+ uniporter (MCU+/-) to address whether reducing mitochondrial Ca2+ uptake alters synaptic transmission and plasticity. We found that cultured MCU+/- hippocampal neurons have impaired Ca2+ clearance, and consequently enhanced synaptic vesicle fusion at presynapses occupied by mitochondria. Furthermore, long-term potentiation (LTP) at mossy fibre (MF) synapses, a process which is dependent on presynaptic Ca2+ accumulation, is enhanced in MCU+/- slices. Our results reveal a previously unrecognized role for mitochondria in regulating presynaptic plasticity of a major excitatory pathway involved in learning and memory
Glasgow 2014, the media and Scottish politics – the (post)imperial symbolism of the Commonwealth Games
This article critically examines print media discourses regarding the 2014 Glasgow Commonwealth Games. The forthcoming analysis considers the political symbolism of the Commonwealth Games with regards to the interlinkages between the British Empire, sport and the global political status of the UK, with specific consideration given to the UK’s declining global power as well as the interconnections between the 2014 Games and the Scottish independence referendum. Hechter’s (1975) ‘internal colonialism’ thesis, which portrays Scotland’s marginalised status within the UK, is drawn upon to critically explore the political symbolism of sport for Scottish nationalism, before discussion focuses upon the extent to which the modern Commonwealth is symptomatic of the UK’s declining status as a global power. Finally, the existence of these narrative tropes in print media coverage of the Commonwealth Games is examined, allowing for critical reflections on the continuing interconnections between the media, sport, nationalism and post-imperial global politics
What proportion of riverine nutrients reaches the open ocean?
Globally, rivers deliver significant quantities of nitrogen (N) and phosphorus (P) to the coastal ocean each year. Currently, there are no viable estimates of how much of this N and P escapes biogeochemical processing on the shelf to be exported to the open ocean; most models of N and P cycling assume that either all or none of the riverine nutrients reach the open ocean. We address this problem by using a simple mechanistic model of how a low-salinity plume behaves outside an estuary mouth. The model results in a global map of riverine water residence times on the shelf, typically a few weeks at low latitudes and up to a year at higher latitudes, which agrees well with observations. We combine the map of plume residence times on the shelf with empirical relationships that link residence time to the proportions of dissolved inorganic N (DIN) and P (DIP) exported and use a database of riverine nutrient loads to estimate the global distribution of riverine DIN and DIP supplied to the open ocean. We estimate that 75% of DIN and 80% of DIP reaches the open ocean. Ignoring processing within estuaries yields annual totals of 17 Tg DIN and 1.2 Tg DIP reaching the open ocean. For DIN this supply is about 50% of that supplied via atmospheric deposition, with significant east-west contrasts across the main ocean basins. The main sources of uncertainty are exchange rates across the shelf break and the empirical relationships between nutrient processing and plume residence time
The United Kingdom and British Empire: A Figurational Approach
Drawing upon the work of Norbert Elias and the process [figurational] sociology perspective, this article examines how state formation processes are related to, and, affected by, expanding and declining chains of international interdependence. In contrast to civic and ethnic conceptions, this approach focuses on the emergence of the nation/nation-state as grounded in broader processes of historical and social development. In doing so, state formation processes within the United Kingdom are related to the expansion and decline of the British Empire. That is, by focusing on the functional dynamics that are embedded in collective groups, one is able to consider how the UK’s ‘state’ and ‘imperial’ figurations were interdependently related to changes in both the UK and the former British Empire. Consequently, by locating contemporary UK relations in the historical context of former imperial relationships, nationalism studies can go ‘beyond’ the nation/nation-state in order to include broader processes of imperial expansion and decline. Here, the relationship between empire and nationalism can offer a valuable insight into contemporary political movements, especially within former imperial groups
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Community compensation in the context of Carbon Capture and Storage: Current debates and practices
Societal opposition has the potential to slow down the implementation of Carbon Capture and Storage (CCS). One of the difficulties is that the perceived benefits associated with a CCS facility for local communities tend to be low compared to its perceived burdens. As is the case for other low carbon technologies, community compensation (or community benefits) has been suggested as a way to restore this perceived imbalance. A diverse literature has looked into the role of community compensation across various land uses and research fields. Synthesis is limited, while at the same time, the provision of community compensation in practice is moving from an ad hoc to a more institutionalized approach. Therefore, it is important to take stock of the literature. This paper provides a review of the community compensation literature in the form of four debates, drawing together environmental social science research on different low carbon technologies (e.g. CCS, renewable energy). In addition, current practices in community compensation for four European countries are discussed. The two parts of this paper are brought together in a set of lessons for the provision of community compensation for future CCS projects; in turn, suggestions for further research are made to address remaining knowledge gaps
Global Patterns of Bacterial Beta-Diversity in Seafloor and Seawater Ecosystems
Background
Marine microbial communities have been essential contributors to global biomass, nutrient cycling, and biodiversity since the early history of Earth, but so far their community distribution patterns remain unknown in most marine ecosystems.
Methodology/Principal Findings
The synthesis of 9.6 million bacterial V6-rRNA amplicons for 509 samples that span the global ocean's surface to the deep-sea floor shows that pelagic and benthic communities greatly differ, at all taxonomic levels, and share <10% bacterial types defined at 3% sequence similarity level. Surface and deep water, coastal and open ocean, and anoxic and oxic ecosystems host distinct communities that reflect productivity, land influences and other environmental constraints such as oxygen availability. The high variability of bacterial community composition specific to vent and coastal ecosystems reflects the heterogeneity and dynamic nature of these habitats. Both pelagic and benthic bacterial community distributions correlate with surface water productivity, reflecting the coupling between both realms by particle export. Also, differences in physical mixing may play a fundamental role in the distribution patterns of marine bacteria, as benthic communities showed a higher dissimilarity with increasing distance than pelagic communities.
Conclusions/Significance
This first synthesis of global bacterial distribution across different ecosystems of the World's oceans shows remarkable horizontal and vertical large-scale patterns in bacterial communities. This opens interesting perspectives for the definition of biogeographical biomes for bacteria of ocean waters and the seabed
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