70 research outputs found
Bulletin of the Texas Archeological Society, Volume 71 (2000), Austin, Paper.
This annual bulletin of the Texas Archeological Society is
a unique contribution specifically focused upon the history of Texas archaeology in a
format that no others have done previously. The volume contains 150 pages, the majority
of which consists of interviews (146 pages) conducted by the first State Archaeologist
of Texas, Curtis Tunnell. In 1968 Tunnell conceived of the idea of obtaining personal
interviews from individuals whom he considered his heroes for their pioneering efforts
in Texas archeology. This volume entails the first publication of such
information, but more will certainly follow. The remaining four pages comprise two
different reviews of other publications important in their own right to those interested
in Southern Plains archeology of Texas. These two reviews by Timothy K Pertulla and
David T. Hughes, respectively, are of The Coronado Expedition to Tierra Nueva: The
1540·1542 Route Across the Southwest by Richard Flint and Shirley Cushing flint, and
GaffCreek: Artifact Collection Strategy and Occupation Prehistory on the Southern High
Plains, Texas County. Oklahoma. The section by Tunnell titled "In Their Own Words:
Stories from Some Pioneer Texas Archeologists" contains numerous previously unpublished
photographs of people, sites and artifacts referred to the texts
MDAN-21: A Bivalent Opioid Ligand Containing mu-Agonist and Delta-Antagonist Pharmacophores and Its Effects in Rhesus Monkeys
MDAN-21, , a bivalent opioid ligand containing a mu-opioid receptor agonist (derived from oxymorphone) linked to the delta-opioid receptor antagonist (related to naltrindole) by a spacer of 21 atoms, was reported to have potent analgesic properties in mice. Tolerance, physical dependence, and conditioned place preference were not evident in that species. The finding that bivalent ligands in this series, with spacers 19 atoms or greater, were devoid of tolerance and dependence led to the proposal that MDAN-21 targets heteromeric mu-delta-opioid receptors. The present study focused on its effects in nonhuman primates (Macaca mulatta), a species with a physiology and behavioral repertoire not unlike humans. With regard to opioids, this species usually better predicts clinical outcomes. MDAN-21 substituted for morphine in morphine-dependent monkeys in the remarkably low dose range 0.006–0.032 mg/kg, subcutaneously. Although MDAN-21 failed to produce reliable thermal analgesia in the dose range 0.0032–0.032 mg/kg, intramuscularly, it was active in the same dose range and by the same route of administration, in the capsaicin-induced thermal allodynia assay. The results suggest that MDAN-21 may be useful in the treatment of opioid dependence and allodynia. The data provide additional evidence that opioid withdrawal is associated with sensitized pain
Phases of Dense Quarks at Large N_c
In the limit of a large number of colors, N_c, we suggest that gauge theories
can exhibit several distinct phases at nonzero temperature and quark density.
Two are familiar: a cold, dilute phase of confined hadrons, where the pressure
is ~ 1, and a hot phase of deconfined quarks and gluons, with pressure ~ N_c^2.
When the quark chemical potential mu ~ 1, the deconfining transition
temperature, T_d, is independent of mu. For T < T_d, as mu increases above the
mass threshold, baryons quickly form a dense phase where the pressure is ~ N_c.
As illustrated by a Skyrme crystal, chiral symmetry can be both spontaneously
broken, and then restored, in the dense phase. While the pressure is ~ N_c,
like that of (non-ideal) quarks, the dense phase is still confined, with
interactions near the Fermi surface those of baryons, and not of quarks. Thus
in the chirally symmetric region, baryons near the Fermi surface are parity
doubled. We suggest possible implications for the phase diagram of QCD.Comment: 23 pages, 2 figures, uses entcs macro. Minor changes in wordin
Interweaving Chiral Spirals
We elaborate how to construct interweaving chiral spirals in (2+1)
dimensions, defined as a superposition of chiral spirals oriented in different
directions. We divide a two-dimensional Fermi sea into distinct wedges,
characterized by the opening angle 2Theta and depth Q ~ pF, where pF is the
Fermi momentum. In each wedge, the energy is lowered by forming a single chiral
spiral. The optimal values for Theta and Q are chosen by balancing this gain in
energy versus the cost of deforming the Fermi surface (which dominates at large
Theta) and patch-patch interactions (dominant at small Theta). Using a
non-local four-Fermi interaction model, we estimate the gain and cost in energy
by expanding in terms of 1/Nc (where Nc is the number of colors), lqcd/Q, and
Theta. Due to a form factor in our non-local model, at small 1/Nc the mass gap
(chiral condensate) is large, and the interaction among quarks and the
condensate local in momentum space. Consequently, interactions between
different patches are localized near their boundaries, and it is simple to
embed many chiral spirals. We identify the dominant and subdominant terms at
high density and categorize formulate an expansion in terms of lqcd/Q or Theta.
The kinetic term in the transverse directions is subdominant, so that
techniques from (1+1)-dimensional systems can be utilized. To leading order in
1/Nc and lqcd/Q, the total gain in energy is ~ pF lqcd^2 with Theta ~
(lqcd/pF)^{3/5}. Since Theta decreases with increasing pF, there should be
phase transitions associated with the change in the wedge number. We also argue
the effects of subdominant terms at lower density where the large-Nc
approximation is more reliable.Comment: 54 pages, 21 figures, published versio
Pediatric DXA: clinical applications
Normal bone mineral accrual requires adequate dietary intake of calcium, vitamin D and other nutrients; hepatic and renal activation of vitamin D; normal hormone levels (thyroid, parathyroid, reproductive and growth hormones); and neuromuscular functioning with sufficient stress upon the skeleton to induce bone deposition. The presence of genetic or acquired diseases and the therapies that are used to treat them can also impact bone health. Since the introduction of clinical DXA in pediatrics in the early 1990s, there has been considerable investigation into the causes of low bone mineral density (BMD) in children. Pediatricians have also become aware of the role adequate bone mass accrual in childhood has in preventing osteoporotic fractures in late adulthood. Additionally, the availability of medications to improve BMD has increased with the development of bisphosphonates. These factors have led to the increased utilization of DXA in pediatrics. This review summarizes much of the previous research regarding BMD in children and is meant to assist radiologists and clinicians with DXA utilization and interpretation
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
Methyl methacrylate and respiratory sensitization: A Critical review
Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants.The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer
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