713 research outputs found
David Glaze and Karr La Miller in a Junior Recital
This is the program for the junior piano recital of David Glaze, and the junior voice recital of mezzo-soprano, Karr La Miller, accompanied by Glenda Plummer on piano. The recital was held on April 26, 1968
Ring Formation from an Oscillating Black Hole
Massive black hole (BH) mergers can result in the merger remnant receiving a
"kick", of order 200 km s or more, which will cause the remnant to
oscillate about the galaxy centre. Here we analyze the case where the BH
oscillates through the galaxy centre perpendicular or parallel to the plane of
the galaxy for a model galaxy consisting of an exponential disk, a Plummer
model bulge, and an isothermal dark matter halo. For the perpendicular motion
we find that there is a strong resonant forcing of the disk radial motion near
but somewhat less than the "resonant radii" where the BH oscillation
frequency is equal one-half, one-fourth, (1/6, etc.) of the radial epicyclic
frequency in the plane of the disk. Near the resonant radii there can be a
strong enhancement of the radial flow and disk density which can lead to shock
formation. In turn the shock may trigger the formation of a ring of stars near
. As an example, for a BH mass of and a kick velocity of
150 km s, we find that the resonant radii lie between 0.2 and 1 kpc. For
BH motion parallel to the plane of the galaxy we find that the BH leaves behind
it a supersonic wake where star formation may be triggered. The shape of the
wake is calculated as well as the slow-down time of the BH.
The differential rotation of the disk stretches the wake into ring-like
segments.Comment: 7 pages, 7 figure
CXD101 and nivolumab in patients with metastatic microsatellite-stable colorectal cancer (CAROSELL): a multicentre, open-label, single-arm, phase II trial.
BACKGROUND: Patients with microsatellite stable (MSS) colorectal carcinoma (CRC) do not respond to immune checkpoint inhibitors. Preclinical models suggested synergistic anti-tumour activity combining CXD101 and anti-programmed cell death protein 1 treatment; therefore, we assessed the clinical combination of CXD101 and nivolumab in heavily pre-treated patients with MSS metastatic CRC (mCRC). PATIENTS AND METHODS: This single-arm, open-label study enrolled patients aged 18 years or older with biopsy-confirmed MSS CRC; at least two lines of systemic anticancer therapies (including oxaliplatin and irinotecan); at least one measurable lesion; Eastern Cooperative Oncology Group performance status of 0, 1 or 2; predicted life expectancy above 3 months; and adequate organ and bone marrow function. Nine patients were enrolled in a safety run-in study to define a tolerable combination schedule of CXD101 and nivolumab, followed by 46 patients in the efficacy assessment phase. Patients in the efficacy assessment cohort were treated orally with 20 mg CXD101 twice daily for 5 consecutive days every 3 weeks, and intravenously with 240 mg nivolumab every 2 weeks. The primary endpoint was immune disease control rate (iDCR). RESULTS: Between 2018 and 2020, 55 patients were treated with CXD101 and nivolumab. The combination therapy was well tolerated with the most frequent grade 3 or 4 adverse events being neutropenia (18%) and anaemia (7%). Immune-related adverse reactions commonly ascribed to checkpoint inhibitors were surprisingly rare although we did see single cases of pneumonitis, hypothyroidism and hypopituitarism. There were no treatment-related deaths. Of 46 patients assessable for efficacy, 4 (9%) achieved partial response and 18 (39%) achieved stable disease, translating to an immune disease control rate of 48%. The median overall survival (OS) was 7.0 months (95% confidence interval 5.13-10.22 months). CONCLUSIONS: The primary endpoint was met in this phase II study, which showed that the combination of CXD101 and nivolumab, at full individual doses in the treatment of advanced or metastatic MSS CRC, was both well tolerated and efficacious
Deep ACS Imaging in the Globular Cluster NGC6397: Dynamical Models
We present N-body models to complement deep imaging of the metal-poor
core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All
simulations include stellar and binary evolution in-step with the stellar
dynamics and account for the tidal field of the Galaxy. We focus on the results
of a simulation that began with 100000 objects (stars and binaries), 5%
primordial binaries and Population II metallicity. After 16 Gyr of evolution
the model cluster has about 20% of the stars remaining and has reached
core-collapse. We compare the color-magnitude diagrams of the model at this age
for the central region and an outer region corresponding to the observed field
of NGC6397 (about 2-3 half-light radii from the cluster centre). This
demonstrates that the white dwarf population in the outer region has suffered
little modification from dynamical processes - contamination of the luminosity
function by binaries and white dwarfs with non-standard evolution histories is
minimal and should not significantly affect measurement of the cluster age. We
also show that the binary fraction of main-sequence stars observed in the
NGC6397 field can be taken as representative of the primordial binary fraction
of the cluster. For the mass function of the main-sequence stars we find that
although this has been altered significantly by dynamics over the cluster
lifetime, especially in the central and outer regions, that the position of the
observed field is close to optimal for recovering the initial mass function of
the cluster stars (below the current turn-off mass). More generally we look at
how the mass function changes with radius in a dynamically evolved stellar
cluster and suggest where the best radial position to observe the initial mass
function is for clusters of any age.Comment: 34 pages, 11 figures, submitted to AJ, companion paper to 0708.403
Close encounters in young stellar clusters: implications for planetary systems in the solar neighbourhood
The stars that populate the solar neighbourhood were formed in stellar
clusters. Through N-body simulations of these clusters, we measure the rate of
close encounters between stars. By monitoring the interaction histories of each
star, we investigate the singleton fraction in the solar neighbourhood. A
singleton is a star which formed as a single star, has never experienced any
close encounters with other stars or binaries, or undergone an exchange
encounter with a binary. We find that, of the stars which formed as single
stars, a significant fraction are not singletons once the clusters have
dispersed. If some of these stars had planetary systems, with properties
similar to those of the solar system, the planets orbits may have been
perturbed by the effects of close encounters with other stars or the effects of
a companion star within a binary. Such perturbations can lead to strong
planet-planet interactions which eject several planets, leaving the remaining
planets on eccentric orbits. Some of the single stars exchange into binaries.
Most of these binaries are broken up via subsequent interactions within the
cluster, but some remain intact beyond the lifetime of the cluster. The
properties of these binaries are similar to those of the observed binary
systems containing extra-solar planets. Thus, dynamical processes in young
stellar clusters will alter significantly any population of solar-system-like
planetary systems. In addition, beginning with a population of planetary
systems exactly resembling the solar system around single stars, dynamical
encounters in young stellar clusters may produce at least some of the
extra-solar planetary systems observed in the solar neighbourhood.Comment: 11 pages, 9 figures, 1 table. Accepted for publication in MNRA
Spatial Epidemiology: Current Approaches and Future Challenges
Spatial epidemiology is the description and analysis of geographic variations in disease with respect to demographic, environmental, behavioral, socioeconomic, genetic, and infectious risk factors. We focus on small-area analyses, encompassing disease mapping, geographic correlation studies, disease clusters, and clustering. Advances in geographic information systems, statistical methodology, and availability of high-resolution, geographically referenced health and environmental quality data have created unprecedented new opportunities to investigate environmental and other factors in explaining local geographic variations in disease. They also present new challenges. Problems include the large random component that may predominate disease rates across small areas. Though this can be dealt with appropriately using Bayesian statistics to provide smooth estimates of disease risks, sensitivity to detect areas at high risk is limited when expected numbers of cases are small. Potential biases and confounding, particularly due to socioeconomic factors, and a detailed understanding of data quality are important. Data errors can result in large apparent disease excess in a locality. Disease cluster reports often arise nonsystematically because of media, physician, or public concern. One ready means of investigating such concerns is the replication of analyses in different areas based on routine data, as is done in the United Kingdom through the Small Area Health Statistics Unit (and increasingly in other European countries, e.g., through the European Health and Environment Information System collaboration). In the future, developments in exposure modeling and mapping, enhanced study designs, and new methods of surveillance of large health databases promise to improve our ability to understand the complex relationships of environment to health
N-body Models of Extended Clusters
We use direct N-body simulations to investigate the evolution of star
clusters with large size-scales with the particular goal of understanding the
so-called extended clusters observed in various Local Group galaxies, including
M31 and NGC6822. The N-body models incorporate a stellar mass function, stellar
evolution and the tidal field of a host galaxy. We find that extended clusters
can arise naturally within a weak tidal field provided that the tidal radius is
filled at the start of the evolution. Differences in the initial tidal
filling-factor can produce marked differences in the subsequent evolution of
clusters and the size-scales that would be observed. These differences are more
marked than any produced by internal evolution processes linked to the
properties of cluster binary stars or the action of an intermediate-mass black
hole, based on models performed in this work and previous work to date. Models
evolved in a stronger tidal field show that extended clusters cannot form and
evolve within the inner regions of a galaxy such as M31. Instead our results
support the suggestion many extended clusters found in large galaxies were
accreted as members of dwarf galaxies that were subsequently disrupted. Our
results also enhance the recent suggestion that star clusters evolve to a
common sequence in terms of their size and mass.Comment: 12 pages, 8 figures, accepted by MNRA
Extratropical age of air trends and causative factors in climate projection simulations
Climate model simulations show an acceleration of the
Brewer–Dobson circulation (BDC) in response to climate change. While the
general mechanisms for the BDC strengthening are widely understood, there
are still open questions concerning the influence of the details of the wave driving. Mean age of stratospheric air (AoA) is a useful transport
diagnostic for assessing changes in the BDC. Analyzing AoA from a subset of
Chemistry–Climate Model Initiative part 1 climate projection simulations, we
find a remarkable agreement between most of the models in simulating the
largest negative AoA trends in the extratropical lower to middle
stratosphere of both hemispheres (approximately between 20 and 25 geopotential kilometers (gpkm) and 20–50∘ N and S). We show that the occurrence of AoA trend minima in those regions is directly
related to the climatological AoA distribution, which is sensitive to an
upward shift of the circulation in response to climate change. Also other
factors like a reduction of aging by mixing (AbM) and residual circulation
transit times (RCTTs) contribute to the AoA distribution changes by widening
the AoA isolines. Furthermore, we analyze the time evolution of AbM and RCTT trends in the extratropics and examine the connection to possible drivers
focusing on local residual circulation strength, net tropical upwelling and
wave driving. However, after the correction for a vertical shift of pressure
levels, we find only seasonally significant trends of residual circulation
strength and zonal mean wave forcing (resolved and unresolved) without a
clear relation between the trends of the analyzed quantities. This indicates
that additional causative factors may influence the AoA, RCTT and AbM
trends. In this study, we postulate that the shrinkage of the stratosphere
has the potential to influence the RCTT and AbM trends and thereby cause
additional AoA changes over time.Czech Science Foundation (GACˇ R) | Ref. 16- 01562JCzech Science Foundation (GACˇ R) | Ref. 18-01625SMinisterio de Ciencia e Innovación | Ref. CGL2015-71575-PXunta de Galicia | Ref. ED481B 2018/103Ministerio de Economía y Competitividad | Ref. RYC-2013-1456
Comparison of risk factors for squamous cell and adenocarcinomas of the cervix: a meta-analysis
While most cancers of the uterine cervix are squamous cell carcinomas, the relative and absolute incidence of adenocarcinoma of the uterine cervix has risen in recent years. It is not clear to what extent risk factors identified for squamous cell carcinoma of the cervix are shared by cervical adenocarcinomas. We used data from six case-control studies to compare directly risk factors for cervical adenocarcinoma (910 cases) and squamous cell carcinoma (5649 cases) in a published data meta-analysis. The summary odds ratios and tests for differences between these summaries for the two histological types were estimated using empirically weighted least squares. A higher lifetime number of sexual partners, earlier age at first intercourse, higher parity and long duration of oral contraceptive use were risk factors for both histological types. Current smoking was associated with a significantly increased risk of squamous cell carcinoma, with a summary odds ratio of 1.47 (95% confidence interval: 1.15-1.88), but not of adenocarcinoma (summary odds ratio=0.82 (0.60-1.11); test for heterogeneity between squamous cell and adenocarcinoma for current smoking: P=0.001). The results of this meta-analysis of published data suggest that squamous cell and adenocarcinomas of the uterine cervix, while sharing many risk factors, may differ in relation to smoking. Further evidence is needed to confirm this in view of the limited data available
From Galaxy Clusters to Ultra-Faint Dwarf Spheroidals: A Fundamental Curve Connecting Dispersion-supported Galaxies to Their Dark Matter Halos
We examine scaling relations of dispersion-supported galaxies over more than
eight orders of magnitude in luminosity by transforming standard fundamental
plane parameters into a space of mass (M1/2), radius (r1/2), and luminosity
(L1/2). We find that from ultra-faint dwarf spheroidals to giant cluster
spheroids, dispersion-supported galaxies scatter about a one-dimensional
"fundamental curve" through this MRL space. The weakness of the M1/2-L1/2 slope
on the faint end may imply that potential well depth limits galaxy formation in
small galaxies, while the stronger dependence on L1/2 on the bright end
suggests that baryonic physics limits galaxy formation in massive galaxies. The
mass-radius projection of this curve can be compared to median dark matter halo
mass profiles of LCDM halos in order to construct a virial mass-luminosity
relationship (Mvir-L) for galaxies that spans seven orders of magnitude in
Mvir. Independent of any global abundance or clustering information, we find
that (spheroidal) galaxy formation needs to be most efficient in halos of Mvir
~ 10^12 Msun and to become inefficient above and below this scale. Moreover,
this profile matching technique is most accurate at the high and low luminosity
extremes (where dark matter fractions are highest) and is therefore quite
complementary to statistical approaches that rely on having a well-sampled
luminosity function. We also consider the significance and utility of the
scatter about this relation, and find that in the dSph regime observational
errors are almost at the point where we can explore the intrinsic scatter in
the luminosity-virial mass relation. Finally, we note that purely stellar
systems like Globular Clusters and Ultra Compact Dwarfs do not follow the
fundamental curve relation. This allows them to be easily distinguished from
dark-matter dominated dSph galaxies in MRL space. (abridged)Comment: 27 pages, 18 figures, ApJ accepted. High-res movies of 3D figures are
available at http://www.physics.uci.edu/~bullock/fcurve/movies.htm
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