559 research outputs found
Safety and Knowledge in God
In recent ”secular’ Epistemology, much attention has been paid to formulating an ”anti-luck’ or ”safety’ condition; it is now widely held that such a condition is an essential part of any satisfactory post-Gettier reflection on the nature of knowledge. In this paper, I explain the safety condition as it has emerged and then explore some implications of and for it arising from considering the God issue. It looks at the outset as if safety might be ”good news’ for a view characteristic of Reformed Epistemology, viz. the view that if Theism is true, many philosophically unsophisticated believers probably know that it’s true. A sub-conclusion of my paper though suggests that as safety does not by itself turn true belief into knowledge, the recent focus on it is not quite such good news for Reformed Epistemologists as they may have hoped: it’s not that safety provides a new route by which they can reach this sort of conclusion. But safety is still good news for their view at least in the sense that there is no reason arising from considering it to count these philosophically unsophisticated believers as not knowing that there’s a God. I conclude by reflecting that good news for Reformed Epistemology is perhaps bad news for the discipline of Philosophy of Religion more generally, as there’s a possible ”reflection destroys knowledge’-implication to be drawn. Those who have been led to their religious beliefs in at least some philosophically unsophisticated ways seem to enjoy much safer religious beliefs than those who have been led to their religious beliefs by philosophical reflection, so the discipline as a whole will be adversely affected if safety is eventually accorded the role of a necessary condition for knowledge
Gait adaptations to awareness and experience of a slip when walking on a cross-slope
Falls that occur as a result of a slip are one of the leading causes of injuries, particularly in the elderly population. Previous studies have focused on slips that occur on a flat surface. Slips on a laterally sloping surface are important and may be related to different mechanisms of balance recovery. This type of slip might result in different gait adaptations to those previously described on a flat surface, but these adaptations have not been investigated. The aim of this study was to assess whether, when walking on a cross-slope, young adults adapted their gait when made aware of a potential slip, and having experienced a slip. Gait parameters were compared for three conditions-(1) Normal walking; (2) Walking after being made aware of a potential slip (participants were told that a slip may occur); (3) Walking after experiencing a slip (Participants had already experienced at least one slip induced using a soapy contaminant). Gait parameters were only analysed for trials in which there was no slippery contaminant present on the walkway. Stride length and walking velocity were significantly reduced, and stance duration was significantly greater in the awareness and experience conditions compared to normal walking, with no significant differences in any gait parameters between the awareness and experience conditions. In addition, 46.7% of the slip trials resulted in a fall. This is higher than reported for slips induced on a flat surface, suggesting slips on a cross-slope are more hazardous. This would help explain the more cautious gait patterns observed in both the awareness and experience conditions
The interaction between transpolar arcs and cusp spots
Transpolar arcs and cusp spots are both auroral phenomena which occur when
the interplanetary magnetic field is northward. Transpolar arcs are associated
with magnetic reconnection in the magnetotail, which closes magnetic flux and
results in a "wedge" of closed flux which remains trapped, embedded in the
magnetotail lobe. The cusp spot is an indicator of lobe reconnection at the
high-latitude magnetopause; in its simplest case, lobe reconnection
redistributes open flux without resulting in any net change in the open flux
content of the magnetosphere. We present observations of the two phenomena
interacting--i.e., a transpolar arc intersecting a cusp spot during part of its
lifetime. The significance of this observation is that lobe reconnection can
have the effect of opening closed magnetotail flux. We argue that such events
should not be rare
Effect of Celluclast 1.5L on the Physicochemical Characterization of Gold Kiwifruit Pectin
The effects of Celluclast 1.5L concentration on the physicochemical characterization of gold kiwifruit pectin was evaluated. Varying the enzyme concentration affected the pectin yield and pectin physicochemical properties. The viscosity of extracted pectin was largely dependent on the enzyme concentration. Celluclast 1.5L with medium concentration exhibited the highest viscosity. Varying the enzyme concentration also influenced the molecular weight distribution. High molecular weight (Mw) pectin (1.65 × 106 g/mol) was obtained when the medium concentration was used. Overall, the study clearly reflects the importance of taking into consideration the amount of cellulytic enzyme added in order to determine the final quality of pectin
Characteristics of Marri (Corymbia calophylla) fruits in relation to the foraging behaviour of the Forest Red-tailed Black Cockatoo (Calyptorhynchus banksii naso)
Forest Red-tailed Black Cockatoos (Calyptorhynchus banksii naso) feed predominantly on seeds of the eucalypt Marri (Corymbia calophylla) and often only from specific feed trees. There was no difference between wet weight of fruits from feed (24.1 ± 1.72 g) and non-feed trees (23.2 ± 1.57 g), but trees from which Forest Red-tailed Black Cockatoos fed had a significantly higher seed number per fruit (3.9 ± 0.18), a greater individual dry seed weight (0.10 ± 0.003 g) and total seed weight per fruit (0.39 ± 0.02 g), and a higher ratio of total seed dry weight to fruit wet weight (0.02 ± 0.001) compared with non-feed trees (3.1 ± 0.20 seeds per fruit; 0.09 ± 0.005 g individual seed dry weight; 0.29 ± 0.020 g total seed dry weight per fruit; 0.013 ± 0.001 ratio of total seed dry weight to fruit wet weight). Discriminate analysis had a limited capacity to predict Marri use by Forest Red-tailed Black Cockatoos, correctly classifying about 70 % of feed trees. Seed number and total seed mass were the best fruit characteristics for the prediction of tree type. We conclude that Forest Red-tailed Black Cockatoos selectively forage from trees with fruits that have a high seed yield, but the method by which the cockatoos select these trees is unclear
First Constraints on Compact Dark Matter from Fast Radio Burst Microstructure
Despite existing constraints, it remains possible that up to of all
dark matter is comprised of compact objects, such as the black holes in the
10-100\,M range whose existence has been confirmed by LIGO. The strong
gravitational lensing of transients such as FRBs and GRBs has been suggested as
a more sensitive probe for compact dark matter than intensity fluctuations
observed in microlensing experiments. Recently ASKAP has reported burst
substructure down to s timescales in FRBs in the redshift range
. We investigate here the implications of this for the detectability
of compact dark matter by FRBs. We find that a sample size of FRBs
would be required to constrain compact dark matter to less than the existing
35 limit with 95 confidence, if it were distributed along Gpc-long FRB sightlines through the cosmic web. Conversely, existing
constraints on the fraction of compact dark matter permit as many as 1 in
of all FRBs to exhibit micro-lensed burst
structure. Approximately FRBs intercepting halos within kpc
would be required to exclude the fraction of compact dark matter in each
intercepted halo to a similar level. Furthermore, we consider the cumulative
effects of lensing of the FRB signal by a macroscopic dark matter distribution.
We conclude that lensing from a uniform distribution of compact objects is
likely not observable, but suggest that FRBs may set meaningful limits on
power-law distributions of dark matter.Comment: 3 Figures, 1 tabl
Two-Screen Scattering in CRAFT FRBs
Temporal broadening is a commonly observed property of fast radio bursts
(FRBs), associated with turbulent media which cause radiowave scattering.
Similarly to dispersion, scattering is an important probe of the media along
the line of sight to an FRB source, such as the circum-burst or circum-galactic
mediums (CGM). Measurements of characteristic scattering times alone are
insufficient to constrain the position of the dominant scattering media along
the line of sight. However, where more than one scattering screen exists,
Galactic scintillation can be leveraged to form strong constraints. We quantify
the scattering and scintillation in 10 FRBs with 1) known host galaxies and
redshifts and 2) captured voltage data enabling high time resolution analysis,
obtained from the Commensal Real-time ASKAP (Australian Square Kilometre Array
Pathfinder) Fast Transient survey science project (CRAFT). We find strong
evidence for two screens in three cases. For FRBs 20190608B and 20210320C, we
find evidence for scattering screens less than approximately 16.7 and 3000 kpc
respectively, from their sources. For FRB 20201124A we find evidence for a
scattering screen at 26 kpc. Each of these measures is consistent with
the scattering occurring in the host ISM (inter-stellar medium) or CGM. If
pulse broadening is assumed to be contributed by the host galaxy ISM or
circum-burst environment, the definitive lack of observed scintillation in four
FRBs in our sample suggests that existing models may be over-estimating
scattering times associated with the Milky Way's ISM, similar to the
anomalously low scattering observed for FRB 20201124A.Comment: 13 pages, 9 figures, 1 table. Submitted to MNRA
The History of Astrophysics in Antarctica
We examine the historical development of astrophysical science in Antarctica
from the early 20th century until today. We find three temporally overlapping
eras, each having a rather distinct beginning. These are the astrogeological
era of meteorite discovery, the high energy era of particle detectors, and the
photon astronomy era of microwave, sub--mm and infrared telescopes, sidelined
by a few niche experiments at optical wavelengths. The favourable atmospheric
and geophysical conditions are briefly examined, followed by an account of the
major experiments and a summary of their results.Comment: 29 pages, 10 figures, 1 table Submitted to PASA in April 200
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