83 research outputs found
Science and Religion: Stepping Toward the Light at the Mouth of the Cave
In analyzing the dialogue between science and religion, the author finds that it is hampered
by three semantic problems. The first denies, or at least undervalues, the two modes of
knowing most apropos to religion: the emotional and the intuitive/mystical modes. Secondly, the uncritical use of language causes considerable confusion. The third problem
limits discussion to what Stephan Schwartz has called the \"Grand Material Paradigm.\" As
the conclusion of the essay, a precis of an alternate cosmology is presented
EFFECTS OF ROAD-STREAM CROSSINGS ON POPULATIONS OF THE IDAHO GIANT SALAMANDER (Dicamptodon aterrimus)
Habitat disturbances affect wildlife populations through numerous mechanisms, and determining specific components of habitat disturbances affecting those populations is challenging. For example, a single disturbance can both change local habitat conditions and impose limitations on dispersal of animals. Both of these components can negatively affect biological responses, such as body condition, local movement patterns, or survival. Culverts are a habitat disturbance having both of these components. Culverts affect local habitat conditions by increasing sediment levels in downstream reaches, negatively affecting animals downstream of culverts. Culverts also impose limits on dispersal by blocking passage of stream organisms to upstream reaches, negatively affecting populations upstream of culverts. Therefore, because the negative effects of the components of the habitat disturbance can be spatially separated (i.e., downstream v. upstream), we can determine which component may be responsible for negative trends attributed to culverts observed at the landscape scale. Road density and culverts have been negatively associated with occupancy of streams by Dicamptodon aterrimus, the Idaho giant salamander, but the underlying mechanism is unknown. I assessed the effects of road culverts on sediment levels and dispersal of D. aterrimus in nine streams. I then assessed the effects of culverts on three biological responses of D. aterrimus: body condition, in-reach movement behavior, and survival. I conducted my study in streams with three crossing types: unimproved culverts, improved culverts, and streams with no culverts. I predicted that changes to local habitat conditions downstream of culverts would negatively affect biological responses of individuals downstream of culverts. I predicted that limits on dispersal to reaches upstream of culverts would negatively affect biological responses in reaches upstream of culverts. I found no evidence culverts affected local habitat conditions, dispersal of D. aterrimus, or biological responses of D. aterrimus. Habitat disturbance from culverts might not affect D. aterrimus because this species is a habitat generalists and may not have responded biologically to the pressures of isolation. Though I did not find evidence that rates of upstream dispersal varied among crossing types, it is logical that unimproved culverts do block the upstream dispersal of aquatic D. aterrimus and reduction of these movements could have negative consequences in the long-term. Therefore, managers should aim to include stream amphibians in stream restoration goals
Identification of Potential Seepage Locations Along the Herbert Hoover Dike, Lake Okeechobee FL., by Electromagnetic Geophysical Method. Prediction and Confirmation.
This case history demonstrates the use of electromagnetic (EM) induction methods to examine known seepage locations and then predict future ones along the Herbert Hoover Dike (HHD) in south central Florida. The HHD forms an embankment dam 20 to 30 feet high and 140 miles long surrounding Lake Okeechobee. Approximately 26 miles of embankment was surveyed with EM induction. The objective of the EM survey was to identify active and potential foundation seepage locations and conduits. Areas of greater conductivity were often associated with seepage locations observed during a record high water event in October, 1995. These problems included boils and piping of foundation and embankment materials. One great benefit of this investigation was that large areas of competent dike foundations could be separated from areas containing potential problems requiring additional examination
GALEX and Optical Light Curves of WX LMi, SDSSJ103100.5+202832.2 and SDSSJ121209.31+013627.7
{\it GALEX} near ultraviolet (NUV) and far-ultraviolet (FUV) light curves of
three extremely low accretion rate polars show distinct modulations in their UV
light curves. While these three systems have a range of magnetic fields from 13
to 70 MG, and of late type secondaries (including a likely brown dwarf in
SDSSJ121209.31+013627.7), the accretion rates are similar, and the UV
observations imply some mechanism is operating to create enhanced emission
zones on the white dwarf. The UV variations match in phase to the two magnetic
poles viewed in the optical in WX LMi and to the single poles evident in the
optical in SDSSJ1212109.31+013627.7 and SDSSJ103100.55+202832.2. Simple spot
models of the UV light curves show that if hot spots are responsible for the UV
variations, the temperatures are on the order of 10,000-14,000K. For the single
pole systems, the size of the FUV spot must be smaller than the NUV and in all
cases, the geometry is likely more complicated than a simple circular spot.Comment: 29 pages, 4 tables, 10 figures, Astrophysical Journal, accepte
Catalog of 93 Nova Light Curves: Classification and Properties
We present a catalog of 93 very-well-observed nova light curves. The light
curves were constructed from 229,796 individual measured magnitudes, with the
median coverage extending to 8.0 mag below peak and 26% of the light curves
following the eruption all the way to quiescence. Our time-binned light curves
are presented in figures and as complete tabulations. We also calculate and
tabulate many properties about the light curves, including peak magnitudes and
dates, times to decline by 2, 3, 6, and 9 magnitudes from maximum, the time
until the brightness returns to quiescence, the quiescent magnitude, power law
indices of the decline rates throughout the eruption, the break times in this
decline, plus many more properties specific to each nova class. We present a
classification system for nova light curves based on the shape and the time to
decline by 3 magnitudes from peak (t3). The designations are S for smooth light
curves (38% of the novae), P for plateaus (21%), D for dust dips (18%), C for
cusp-shaped secondary maxima (1%), O for quasi-sinusoidal oscillations
superposed on an otherwise smooth decline (4%), F for flat-topped light curves
(2%), and J for jitters or flares superposed on the decline (16%). Our
classification consists of this single letter followed by the t3 value in
parentheses; so for example V1500 Cyg is S(4), GK Per is O(13), DQ Her is
D(100), and U Sco is P(3).Comment: Astronomical Journal, in press, 19 figures, 73 page
The Monitor project: JW 380 -- a 0.26, 0.15 Msol pre main sequence eclipsing binary in the Orion Nebula Cluster
We report the discovery of a low-mass (0.26 +/- 0.02, 0.15 +/- 0.01 Msol)
pre-main-sequence eclipsing binary with a 5.3 day orbital period. JW 380 was
detected as part of a high-cadence time-resolved photometric survey (the
Monitor project) using the 2.5m Isaac Newton Telescope and Wide Field Camera
for a survey of a single field in the Orion Nebula Cluster (ONC) region in V
and i bands. The star is assigned a 99 per cent membership probability from
proper motion measurements, and radial velocity observations indicate a
systemic velocity within 1 sigma of that of the ONC. Modelling of the combined
light and radial velocity curves of the system gave stellar radii of 1.19 +0.04
-0.18 Rsol and 0.90 +0.17 -0.03 Rsol for the primary and secondary, with a
significant third light contribution which is also visible as a third peak in
the cross-correlation functions used to derive radial velocities. The masses
and radii appear to be consistent with stellar models for 2-3 Myr age from
several authors, within the present observational errors. These observations
probe an important region of mass-radius parameter space, where there are
currently only a handful of known pre-main-sequence eclipsing binary systems
with precise measurements available in the literature.Comment: 11 pages, 9 figures, accepted for publication in MNRA
Correction to: HIF prolyl hydroxylase inhibition protects skeletal muscle from eccentric contraction induced injury
Following publication of the original article [1], the authors flagged that there is a discrepancy with the Availability of data and materials statement on page 12 of the article
Inference of hidden structures in complex physical systems by multi-scale clustering
We survey the application of a relatively new branch of statistical
physics--"community detection"-- to data mining. In particular, we focus on the
diagnosis of materials and automated image segmentation. Community detection
describes the quest of partitioning a complex system involving many elements
into optimally decoupled subsets or communities of such elements. We review a
multiresolution variant which is used to ascertain structures at different
spatial and temporal scales. Significant patterns are obtained by examining the
correlations between different independent solvers. Similar to other
combinatorial optimization problems in the NP complexity class, community
detection exhibits several phases. Typically, illuminating orders are revealed
by choosing parameters that lead to extremal information theory correlations.Comment: 25 pages, 16 Figures; a review of earlier work
HIF prolyl hydroxylase inhibition protects skeletal muscle from eccentric contraction-induced injury
BACKGROUND: In muscular dystrophy and old age, skeletal muscle repair is compromised leading to fibrosis and fatty tissue accumulation. Therefore, therapies that protect skeletal muscle or enhance repair would be valuable medical treatments. Hypoxia-inducible factors (HIFs) regulate gene transcription under conditions of low oxygen, and HIF target genes EPO and VEGF have been associated with muscle protection and repair. We tested the importance of HIF activation following skeletal muscle injury, in both a murine model and human volunteers, using prolyl hydroxylase inhibitors that stabilize and activate HIF.
METHODS: Using a mouse eccentric limb injury model, we characterized the protective effects of prolyl hydroxylase inhibitor, GSK1120360A. We then extended these studies to examine the impact of EPO modulation and infiltrating immune cell populations on muscle protection. Finally, we extended this study with an experimental medicine approach using eccentric arm exercise in untrained volunteers to measure the muscle-protective effects of a clinical prolyl hydroxylase inhibitor, daprodustat.
RESULTS: GSK1120360A dramatically prevented functional deficits and histological damage, while accelerating recovery after eccentric limb injury in mice. Surprisingly, this effect was independent of EPO, but required myeloid HIF1α-mediated iNOS activity. Treatment of healthy human volunteers with high-dose daprodustat reduced accumulation of circulating damage markers following eccentric arm exercise, although we did not observe any diminution of functional deficits with compound treatment.
CONCLUSION: The results of these experiments highlight a novel skeletal muscle protective effect of prolyl hydroxylase inhibition via HIF-mediated expression of iNOS in macrophages. Partial recapitulation of these findings in healthy volunteers suggests elements of consistent pharmacology compared to responses in mice although there are clear differences between these two systems
Contribution of primary motor cortex to compensatory balance reactions
<p>Abstract</p> <p>Background</p> <p>Rapid compensatory arm reactions represent important response strategies following an unexpected loss of balance. While it has been assumed that early corrective actions arise largely from sub-cortical networks, recent findings have prompted speculation about the potential role of cortical involvement. To test the idea that cortical motor regions are involved in early compensatory arm reactions, we used continuous theta burst stimulation (cTBS) to temporarily suppress the hand area of primary motor cortex (M1) in participants prior to evoking upper limb balance reactions in response to whole body perturbation. We hypothesized that following cTBS to the M1 hand area evoked EMG responses in the stimulated hand would be diminished. To isolate balance reactions to the upper limb participants were seated in an elevated tilt-chair while holding a stable handle with both hands. The chair was held vertical by a magnet and was triggered to fall backward unpredictably. To regain balance, participants used the handle to restore upright stability as quickly as possible with both hands. Muscle activity was recorded from proximal and distal muscles of both upper limbs.</p> <p>Results</p> <p>Our results revealed an impact of cTBS on the amplitude of the EMG responses in the stimulated hand muscles often manifest as inhibition in the stimulated hand. The change in EMG amplitude was specific to the target hand muscles and occasionally their homologous pairs on the non-stimulated hand with no consistent effects on the remaining more proximal arm muscles.</p> <p>Conclusions</p> <p>Present findings offer support for cortical contributions to the control of early compensatory arm reactions following whole-body perturbation.</p
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