3,042 research outputs found
The Call of Duty and Beyond: Problems Concerning Justification and Virtue in the Ethical Models of Epistemology
Internalist considerations are crucial to a good theory of belief formationâepistemic or ethical. To get to this conclusion, the author first shows the insufficiency of a strong externalist account of true belief; he critiqueâs Plantingaâs reliabilism by way of demonstration. Plantingaâs idea of epistemic warrant shares a maximum ideal with utilitarianism (the desire for the most true beliefs), but the good intentions of the theory are undermined by 1) the authorâs car counter-example that illustrates the relevance of internal circumstances, and 2) a realization that Plantinga pays no mind to volition variance. Next, the author analyzes Linda Trinkaus Zagzebskiâs virtue ethics and notes its own form of reliabilism but promising internalist account of justification. Despite the fact that both theorists can be used improperly to reward vicious means to ends, such as guessing, Zagzebskiâs virtue ethics improves the reliability of Plantingaâs epistemology
The âmissingâ politics of whiteness and rightful presence in the settler colonial city
This is the author accepted manuscript. The final version is available from Sage publications via the DOI in this record.This paper engages the global nexus of colonization, racialization, and
urbanization through the settler colonial city of Kelowna, British Columbia
(BC), Canada. Kelowna is known for its recent, rapid urbanization and for
its ongoing, disproportionate âwhiteness,â understood as a complex political
geography that enacts boundaries of inclusion and exclusion. The white
urban identity of Kelowna defines Indigenous and migrant communities as
âmissingâ or âout-of-place,â yet these configurations of âmissingâ are
politically contested. This paper examines how differential processes of
racialization and urbanization establish the whiteness of this settler-colonial
city, drawing attention to ways that âmissingâ communities remake
relations of ârightful presenceâ in the city, against dominant racialized,
colonial, and urban narratives of their absence and processes of their
displacement. Finally, this paper considers how a politics of ârightful
presenceâ needs to be reconfigured in the settler-colonial city, which itself
has no rightful presence on unceded Indigenous land
IRAS asteroid families
The Infrared Astronomical Satellite (IRAS) sampled the entire asteroid population at wavelengths from 12 to 100 microns during its 1983 all sky survey. The IRAS Minor Planet Survey (IMPS) includes updated results for more recently numbered as well as other additional asteroids with reliable orbital elements. Albedos and diameters were derived from the observed thermal emission and assumed absolute visual magnitudes and then entered into the IMPS database at the Infrared Processing and Analysis Center (IPAC) for members of the Themis, Eos, Koronis and Maria asteroid families and compared with their visual colors. The IMPS results for the small (down to about 20 km) asteroids within these major families confirm trends previously noted for their larger members. Each of these dynamical families which are defined by their similar proper elements appears to have homogeneous physical properties
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An updated Antarctic melt record through 2009 and its linkages to high-latitude and tropical climate variability
A 30-year minimum Antarctic snowmelt record occurred during austral summer 2008â2009 according to spaceborne microwave observations for 1980â2009. Strong positive phases of both the El-Niño Southern Oscillation (ENSO) and the Southern Hemisphere Annular Mode (SAM) were recorded during the months leading up to and including the 2008â2009 melt season. The 30-year record confirms that significant negative correlations exist at regional and continental scales between austral summer melting and both the ENSO and SAM indices for OctoberâJanuary. In particular, the strongest negative melting anomalies (such as those in 2008 and 2009) are related to amplified large-scale atmospheric forcing when both the SAM and ENSO are in positive phases. Our results suggest that enhanced snowmelt is likely to occur if recent positive summer SAM trends subside in conjunction with the projected recovery of stratospheric ozone levels, with subsequent impacts on ice sheet mass balance and sea level trends
Retrieval of Dry Snow Parameters from Radiometric Data Using a Dense Medium Model and Genetic Algorithms
In this paper, GA-based techniques are used to invert the equations of an electromagnetic model based on Dense Medium Radiative Transfer Theory (DMRT) under the Quasi Crystalline Approximation with Coherent Potential to retrieve snow depth, mean grain size and fractional volume from microwave brightness temperatures. The technique is initially tested on both noisy and not-noisy simulated data. During this phase, different configurations of genetic algorithm parameters are considered to quantify how their change can affect the algorithm performance. A configuration of GA parameters is then selected and the algorithm is applied to experimental data acquired during the NASA Cold Land Process Experiment. Snow parameters retrieved with the GA-DMRT technique are then compared with snow parameters measured on field
A ring as a model of the main belt in planetary ephemerides
We assess the ability of a solid ring to model a global perturbation induced
by several thousands of main-belt asteroids. The ring is first studied in an
analytical framework that provides an estimate of all the ring's parameters
excepting mass. In the second part, numerically estimated perturbations on the
Earth-Mars, Earth-Venus, and Earth-Mercury distances induced by various subsets
of the main-belt population are compared with perturbations induced by a ring.
To account for large uncertainties in the asteroid masses, we obtain results
from Monte Carlo experiments based on asteroid masses randomly generated
according to available data and the statistical asteroid model. The radius of
the ring is analytically estimated at 2.8 AU. A systematic comparison of the
ring with subsets of the main belt shows that, after removing the 300 most
perturbing asteroids, the total main-belt perturbation of the Earth-Mars
distance reaches on average 246 m on the 1969-2010 time interval. A ring with
appropriate mass is able to reduce this effect to 38 m. We show that, by
removing from the main belt ~240 asteroids that are not necessarily the most
perturbing ones, the corresponding total perturbation reaches on average 472 m,
but the ring is able to reduce it down to a few meters, thus accounting for
more than 99% of the total effect.Comment: 18 pages, accepted in A&
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Persistent surface snowmelt over Antarctica (1987â2006) from 19.35 GHz brightness temperatures
[1] Persistent melting (e.g., continuing for more than three days or for one consecutive day and night) is mapped in Antarctica (1987â2006) using night- and day-time Special Sensor Microwave Imager brightness temperatures (Tb) at 19.35 GHz, horizontal polarization. Snowmelt is indicated when Tb and relative daily difference exceed threshold values, respectively Tc and ÎT, computed for each pixel and year, or when both daytime and nighttime Tb exceed Tc. Results from an electromagnetic model suggest that the minimum detectable liquid water content ranges between 0.2 and 0.5%, in volume. We find that melting areas have been moving inland since 1987. A first-time extensive melting (1987â2006) is detected over the Transantarctic Mountains on January 2005, 875 Km inland and 2000 m above sea level. Melting extent and index have been decreasing over Antarctica, since 1987, although either positive and negative trends are observed from a sub-continental scale analysis
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