title: Rates of photospheric magnetic flux cancellation measured with Hinode

authors: Park, Soyoung

subjects: magnetic fields

abstract: Photospheric magnetic flux cancellation on the Sun is generally believed to be caused by magnetic reconnection occurring in the low solar atmosphere. Individual canceling magnetic features are observationally characterized by the rate of flux cancellation. The specific cancellation rate, defined as the rate of flux cancellation divided by the interface length, gives an accurate estimate of the electric field in the reconnecting current sheet. We have determined the specific cancellation rate using the magnetograms taken by the Solar Optical Telescope (SOT) aboard the Hinode satellite. The specific rates determined with SOT turned out to be systematically higher than those based on the data taken by the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory. The median value of the specific cancellation rate was found to be 8 × 106 G cm s-1—a value four times that obtained from the MDI data. This big difference is mainly due to a higher angular resolution and better sensitivity of the SOT, resulting in magnetic fluxes up to five times larger than those obtained from the MDI. The higher rates of flux cancellation correspond to either faster inflows or stronger magnetic fields of the reconnection inflow region, which may have important consequences for the physics of photospheric magnetic reconnection.

text: Rates of photospheric magnetic flux cancellation measured with Hinode Photospheric magnetic flux cancellation on the Sun is generally believed to be caused by magnetic reconnection occurring in the low solar atmosphere. Individual canceling magnetic features are observationally characterized by the rate of flux cancellation. The specific cancellation rate, defined as the rate of flux cancellation divided by the interface length, gives an accurate estimate of the electric field in the reconnecting current sheet. We have determined the specific cancellation rate using the magnetograms taken by the Solar Optical Telescope (SOT) aboard the Hinode satellite. The specific rates determined with SOT turned out to be systematically higher than those based on the data taken by the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory. The median value of the specific cancellation rate was found to be 8 × 106 G cm s-1—a value four times that obtained from the MDI data. This big difference is mainly due to a higher angular resolution and better sensitivity of the SOT, resulting in magnetic fluxes up to five times larger than those obtained from the MDI. The higher rates of flux cancellation correspond to either faster inflows or stronger magnetic fields of the reconnection inflow region, which may have important consequences for the physics of photospheric magnetic reconnection.

year: 2009

title: The meaning of meaning-fallibilism

authors: Legg, Catherine

subjects: fallibilism

abstract: Much discussion of meaning by philosophers over the last 300 years has been predicated on a Cartesian first-person authority (i.e. ‘infallibilism’) with respect to what one’s terms mean. However this has problems making sense of the way the meanings of scientific terms develop, an increase in scientific knowledge over and above scientists’ ability to quantify over new entities. Although a recent conspicuous embrace of rigid designation has broken up traditional meaning-infallibilism to some extent, this new dimension to the meaning of terms such as ‘water’ is yet to receive a principled epistemological undergirding (beyond the deliverances of ‘intuition’ with respect to certain somewhat unusual possible worlds). 
     Charles Peirce’s distinctive, naturalistic philosophy of language is mined to provide a more thoroughly fallibilist, and thus more realist, approach to meaning, with the requisite epistemology. Both his pragmatism and his triadic account of representation, it is argued, produce an original approach to meaning, analysing it in processual rather than objectual terms, and opening a distinction between ‘meaning for us’, the meaning a term has at any given time for any given community and ‘meaning simpliciter’, the way use of a given term develops over time (often due to a posteriori input from the world which is unable to be anticipated in advance). This account provocatively undermines a certain distinction between ‘semantics’ and ‘ontology’ which is often taken for granted in discussions of realism.

text: The meaning of meaning-fallibilism Much discussion of meaning by philosophers over the last 300 years has been predicated on a Cartesian first-person authority (i.e. ‘infallibilism’) with respect to what one’s terms mean. However this has problems making sense of the way the meanings of scientific terms develop, an increase in scientific knowledge over and above scientists’ ability to quantify over new entities. Although a recent conspicuous embrace of rigid designation has broken up traditional meaning-infallibilism to some extent, this new dimension to the meaning of terms such as ‘water’ is yet to receive a principled epistemological undergirding (beyond the deliverances of ‘intuition’ with respect to certain somewhat unusual possible worlds). 
     Charles Peirce’s distinctive, naturalistic philosophy of language is mined to provide a more thoroughly fallibilist, and thus more realist, approach to meaning, with the requisite epistemology. Both his pragmatism and his triadic account of representation, it is argued, produce an original approach to meaning, analysing it in processual rather than objectual terms, and opening a distinction between ‘meaning for us’, the meaning a term has at any given time for any given community and ‘meaning simpliciter’, the way use of a given term develops over time (often due to a posteriori input from the world which is unable to be anticipated in advance). This account provocatively undermines a certain distinction between ‘semantics’ and ‘ontology’ which is often taken for granted in discussions of realism.

year: 2005-06

title: Land/seascapes of exclusion: social order on the coastal margins

authors: Ryks, John

abstract: The hegemonic discourse of coastal planning and development has an impact on the social ordering of Aotearoa/New Zealand’s coastal communities in a number of ways. One way in which social order is controlled and maintained is through the (ab)use of boundaries. Boundaries constructed and maintained under the authority of government and/or funded by development dictate where people may or may not live. In many cases these boundaries are used as instruments of exclusion. Boundaries constructed by hegemonic groups exclude those who define the coast according to other criteria. The hegemonic deployment of boundaries and the domination of coastal people and place generally is explored through an analysis of discourse. This analysis is structured according to differences in social order, coded as places of Otherness (heterotopia), Euclidean coasts, and places in transition reflecting images of both the former and the latter.
Drawing on a number of coastal communities, including the Northland community of Otia (otherwise known as the Seaweed Pickers), Taylor’s Mistake, Whitianga and the wealth enclave of Pauanui, it is shown that the land/seascape of coastal Aotearoa/New Zealand is gradually being disciplined through the design of coasts that are accommodating of a particular patronage. These ‘exclusive’ coasts appear in stark contrast to those places where an alternative social ordering takes place. Here, in the absence of a Euclidean spatiality, uncertainty and liminality feature in the social construction of the coast. Residents of these places mark out and define the coast in a way that is quite different from the accepted norm, a fact that determines a particular ‘cartographic anxiety’ on the part of the dominant. This anxiety is instrumental in the construction of Otherness and the (re)production of exclusion.

text: Land/seascapes of exclusion: social order on the coastal margins The hegemonic discourse of coastal planning and development has an impact on the social ordering of Aotearoa/New Zealand’s coastal communities in a number of ways. One way in which social order is controlled and maintained is through the (ab)use of boundaries. Boundaries constructed and maintained under the authority of government and/or funded by development dictate where people may or may not live. In many cases these boundaries are used as instruments of exclusion. Boundaries constructed by hegemonic groups exclude those who define the coast according to other criteria. The hegemonic deployment of boundaries and the domination of coastal people and place generally is explored through an analysis of discourse. This analysis is structured according to differences in social order, coded as places of Otherness (heterotopia), Euclidean coasts, and places in transition reflecting images of both the former and the latter.
Drawing on a number of coastal communities, including the Northland community of Otia (otherwise known as the Seaweed Pickers), Taylor’s Mistake, Whitianga and the wealth enclave of Pauanui, it is shown that the land/seascape of coastal Aotearoa/New Zealand is gradually being disciplined through the design of coasts that are accommodating of a particular patronage. These ‘exclusive’ coasts appear in stark contrast to those places where an alternative social ordering takes place. Here, in the absence of a Euclidean spatiality, uncertainty and liminality feature in the social construction of the coast. Residents of these places mark out and define the coast in a way that is quite different from the accepted norm, a fact that determines a particular ‘cartographic anxiety’ on the part of the dominant. This anxiety is instrumental in the construction of Otherness and the (re)production of exclusion.

year: 2002