3,468 research outputs found
Reduction of Ion Heating During Magnetic Reconnection by Large-Scale Effective Potentials
The physical processes that control the partition of released magnetic energy
between electrons and ions during reconnection is explored through
particle-in-cell simulations and analytical techniques. We demonstrate that the
development of a large-scale parallel electric field and its associated
potential controls the relative heating of electrons and ions. The potential
develops to restrain heated exhaust electrons and enhances their heating by
confining electrons in the region where magnetic energy is released.
Simultaneously the potential slows ions entering the exhaust below the
Alfv\'enic speed expected from the traditional counterstreaming picture of ion
heating. Unexpectedly, the magnitude of the potential and therefore the
relative partition of energy between electrons and ions is not a constant but
rather depends on the upstream parameters and specifically the upstream
electron normalized temperature (electron beta). These findings suggest that
the fraction of magnetic energy converted into the total thermal energy may be
independent of upstream parameters
Satellite versus ground-based estimates of burned area: a comparison between MODIS based burned area and fire agency reports over North America in 2007
North American wildfire management teams routinely assess burned area on site during firefighting campaigns; meanwhile, satellite observations provide systematic and global burned-area data. Here we compare satellite and ground-based daily burned area for wildfire events for selected large fires across North America in 2007 on daily timescales. In a sample of 26 fires across North America, we found the Global Fire Emissions Database Version 4 (GFED4) estimated about 80% of the burned area logged in ground-based Incident Status Summary (ICS-209) over 8-day analysis windows. Linear regression analysis found a slope between GFED and ICS-209 of 0.67 (with R = 0.96). The agreement between these data sets was found to degrade at short timescales (from R = 0.81 for 4-day to R = 0.55 for 2-day). Furthermore, during large burning days (> 3000 ha) GFED4 typically estimates half of the burned area logged in the ICS-209 estimates
Just wrong? Or just WEIRD? Investigating the prevalence of moral dumbfounding in non-Western samples
Moral dumbfounding is the phenomenon that is observed when people defend a moral judgement even though they cannot provide a reason for this judgement. Dumbfounded responding may include admitting to not having reasons, or the use of unsupported declarations (e.g., “It’s just wrong”) as justification for a judgement. Published evidence for dumbfounding has drawn exclusively on samples of WEIRD backgrounds (Western, educated, industrialised, rich, and democratic), and it remains unclear whether the phenomenon is generalilsable to other populations. In three studies we apply a standardised moral dumbfounding task, and show evidence for moral dumbfounding in a Chinese sample (Study 1), an Indian sample (Study 2), and a mixed sample primarily from North Africa and the Middle East (MENA region, Study 3)
Normative Alethic Pluralism
Some philosophers have argued that truth is a norm of judgement and have provided a variety of formulations of this general thesis. In this paper, I shall side with these philosophers and assume that truth is a norm of judgement. What I am primarily interested in here are two core questions concerning the judgement-truth norm: (i) what are the normative relationships between truth and judgement? And (ii) do these relationships vary or are they constant? I argue for a pluralist picture—what I call Normative Alethic Pluralism (NAP)—according to which (i) there is more than one correct judgement-truth norm and (ii) the normative relationships between truth and judgement vary in relation to the subject matter of the judgement. By means of a comparative analysis of disagreement in three areas of the evaluative domain—refined aesthetics, basic taste and morality—I show that there is an important variability in the normative significance of disagreement—I call this the variability conjecture. By presenting a variation of Lynch’s scope problem for alethic monism, I argue that a monistic approach to the normative function of truth is unable to vindicate the conjecture. I then argue that normative alethic pluralism provides us with a promising model to account for it
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