901 research outputs found
Ionization Sources and Physical Conditions in the Diffuse Ionized Gas Halos of Four Edge-On Galaxies
Deep long-slit spectra of the diffuse ionized gas halos of the edge-on spiral
galaxies NGC 4302 and UGC 10288 are presented. These data, along with
previously presented data for NGC 5775 and NGC 891, are used to address the
issue of how DIG halos are energized. Composite photo-ionization/shock models
are generally better at explaining runs of line ratios in these galaxies than
photo-ionization models alone. Models of line ratios in NGC 5775 require a
greater contribution from shocks for filamentary regions than for
non-filamentary regions to explain the run of [OIII]/Halpha. In either case,
the [SII]/[NII] ratio is not well fit by the models. Composite models for UGC
10288 are successful at reproducing the run of [SII]/[NII] for all but the the
highest values of [NII]/Halpha; however, the run of [OIII]/Halpha vs.
[NII]/Halpha does not show any discernible trend, making it difficult to
determine whether or not shocks make a contribution.
We also examine whether the data can be explained simply by an increase in
temperature with z in a pure photo-ionization model. Runs of [SII]/Halpha,
[NII]/Halpha, and [SII]/[NII] in each of the four galaxies are consistent with
such an increase. However, the runs of [OIII]/Halpha vs. z in NGC 5775 and UGC
10288 require unusually high ionization fractions of O^{++} that can not be
explained without invoking a secondary ionization source or at the very least a
much higher temperature for the [OIII]-emitting component than for the [SII]-
and [NII]-emitting component. An increase in temperature with z is generally
more successful at explaining the [OIII]/Halpha run in NGC 891.Comment: 42 pages in aaspp4.sty format. This includes the 19 figures.
Reference added. Accepted for publication in Ap
Displacement, Identity and Belonging for Ibyangin: The Personal Journey of Transracial Korean-Born Adoptees
The present study examined the lived experience (erlebnis) of adult transracial, Korean-born adoptees (Ibyangin; Yngvesson & Coutin, 2006) raised in the United States by White families. Long interviews (McCracken, 1988) were conducted with fourteen young adult (age 26-30) Korean-born adoptees in-person or by phone. The study was anchored in the constructivist-interpretivist research paradigm (Ponterotto, 2005) and utilized the phenomenological inquiry model (Moustakas, 1994) to explore the essence of the international transracial adoption experience. Two major clusters of meaning with additional subthemes were related to a) identity development, and b) decision to return to Korea. Limitations of the study are reviewed, implications for follow-up research are presented, and clinical applications are addressed
Nanoscale phase separation in the iron chalcogenide superconductor K0.8Fe1.6Se2 as seen via scanning nanofocused x-ray diffraction
Advanced synchrotron radiation focusing down to a size of 300 nm has been
used to visualize nanoscale phase separation in the K0.8Fe1.6Se2
superconducting system using scanning nanofocus single-crystal X-ray
diffraction. The results show an intrinsic phase separation in K0.8Fe1.6Se2
single crystals at T< 520 K, revealing coexistence of i) a magnetic phase
characterized by an expanded lattice with superstructures due to Fe vacancy
ordering and ii) a non-magnetic phase with an in-plane compressed lattice. The
spatial distribution of the two phases at 300 K shows a frustrated or arrested
nature of the phase separation. The space-resolved imaging of the phase
separation permitted us to provide a direct evidence of nanophase domains
smaller than 300 nm and different micrometer-sized regions with percolating
magnetic or nonmagnetic domains forming a multiscale complex network of the two
phases.Comment: 5 pages, 4 figure
HERMIONE: a randomized Phase 2 trial of MM-302 plus trastuzumab versus chemotherapy of physician's choice plus trastuzumab in patients with previously treated, anthracycline-naïve, HER2-positive, locally advanced/metastatic breast cancer.
BackgroundHuman epidermal growth factor receptor 2 (HER2)-positive breast cancer is a particularly aggressive form of the disease, and ultimately progresses in patients with metastases on standard therapies. Anthracyclines, such as doxorubicin, are an effective treatment for HER2-positive breast cancer, particularly when administered in combination with trastuzumab - however, doxorubicin-related cardiotoxicity has limited its use. Many patients are therefore never treated with anthracyclines, even upon disease progression, despite the potential for benefit. MM-302 is a novel, HER2-targeted antibody-liposomal doxorubicin conjugate that specifically targets HER2-overexpressing cells. Preclinical and Phase 1 data suggest that MM-302, as a monotherapy or in combination with trastuzumab, could be effective for managing previously treated, anthracycline-naïve, HER2-positive breast cancer, without the cardiotoxicity observed with free doxorubicin formulations.Methods/designHERMIONE is an open-label, multicenter, randomized (1:1) Phase 2 trial of MM-302 plus trastuzumab versus chemotherapy of physician's choice (gemcitabine, capecitabine, or vinorelbine) plus trastuzumab planned to enroll 250 anthracycline-naïve patients with locally advanced/metastatic HER2-positive breast cancer. Key inclusion criteria are: previous treatment with trastuzumab (with or without pertuzumab) in any setting; refractory or intolerant to pertuzumab (refractory to pertuzumab defined as progression in the locally advanced or metastatic setting, or disease recurrence during or within 12 months of completing pertuzumab-containing neoadjuvant and/or adjuvant therapy); and disease progression on, or intolerant to, ado-trastuzumab emtansine for locally advanced or metastatic disease. The trial is currently being conducted at sites in the USA, Canada, and Western Europe. Treatment will be administered in 21-day cycles, and will be continued until disease progression or unacceptable toxicity. The primary endpoint is independently assessed progression-free survival (PFS). Tumor response will be assessed every 6 weeks, and defined according to RECIST v1.1. Secondary endpoints include investigator-assessed PFS, overall survival (OS), OS rates at 6 months and 1 year, objective response rates, safety and tolerability, quality of life, and the pharmacokinetic profile of MM-302 plus trastuzumab.DiscussionThe HERMIONE study will evaluate the efficacy and safety of MM-302 plus trastuzumab in patients with refractory HER2-positive advanced/metastatic breast cancer for whom there are no standard of care therapies with a proven survival advantage.Trial registrationClinicaltrials.gov identifier: NCT02213744 . Registration date: 06AUG2014
STIS ultraviolet/optical spectroscopy of `warm' ultraluminous infrared galaxies
(Abridged) We present high spatial resolution ultraviolet and optical
spectroscopy, obtained using the Space Telescope Imaging Spectrograph on board
the Hubble Space Telescope, of nuclear structures within four `warm'
Ultraluminous Infrared Galaxies (ULIRGs). We find an AGN in at least three, and
probably all four of our sample, hosted in a compact, optically luminous
`knot'. In three cases these knots were previously identified as a putative AGN
nucleus from multiband optical imaging. Three of the sample also harbor a
starburst in one or more knots, suggesting that the optically luminous knots
seen in local ULIRGs are the most likely sites of the dust-shrouded starburst
and AGN activity that power the infrared emission. The four AGN have a diverse
range of properties; two are classical narrow line AGN, one shows both broad
and narrow lines and evidence for lines of sight from the narrow through to the
broad line regions, and one is plausibly a FeLoBAL AGN. The probable presence
in one object of an FeLoBAL AGN, which are extremely rare in the QSO
population, supports the idea that LoBAL AGN may be youthful systems shrouded
in gas and dust rather than AGN viewed along a certain line of sight. The three
starbursts for which detailed constraints are possible show a smaller range in
properties; all three bursts are young with two having ages of ~4Myr and the
third having an age of 20Myr, suggesting that ULIRGs undergo several bursts of
star formation during their lifetimes. None of the starbursts show evidence for
Initial Mass Function slopes steeper than about 3.3. The metallicities of the
knots for which metallicities can be derived are all at least 1.5 times the
Solar value. The properties of one further starburst knot are consistent with
it being the forming core of an elliptical galaxy.Comment: ApJ, accepte
The Nuclear Spectral Energy Distribution of NGC 4395, The Least Luminous Type 1 Seyfert Galaxy
We present X-ray (ROSAT), infrared, and radio observations of NGC 4395, which
harbors the optically least luminous type 1 Seyfert nucleus discovered thus
far. In combination with published optical and ultraviolet spectra, we have
used these data to assemble the broadband spectral energy distribution (SED) of
the galaxy's nucleus. Interestingly, the SED of NGC 4395 differs markedly from
the SEDs of both quasars and typical low-luminosity active galactic nuclei,
which may be a manifestation of the different physical conditions (i.e., black
hole masses, accretion rates, and/or accretion modes) that exist in these
objects. The nuclear X-ray source in NGC 4395 is variable and has an observed
luminosity of just ~ 10^38 ergs/s. Although this emission could plausibly be
associated with either a weak active nucleus or a bright stellar-mass binary
system, the optical and ultraviolet emission-line properties of the nucleus
strongly suggest that the X-rays arise from a classical AGN.Comment: Accepted for publication in PASP (July 1999), 17 pages, including 4
Postscript figure
Increased respiratory symptoms following surgery in children exposed to environmental tobacco smoke
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75635/1/j.1460-9592.2003.01100.x.pd
A Simple Iterative Model Accurately Captures Complex Trapline Formation by Bumblebees Across Spatial Scales and Flower Arrangements
PMCID: PMC3591286This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
A Broadband Study of the Emission from the Composite Supernova Remnant MSH 11-62
MSH 11-62 (G291.1-0.9) is a composite supernova remnant for which radio and
X-ray observations have identified the remnant shell as well as its central
pulsar wind nebula. The observations suggest a relatively young system
expanding into a low density region. Here we present a study of MSH 11-62 using
observations with the Chandra, XMM-Newton, and Fermi observatories, along with
radio observations from the Australia Telescope Compact Array (ATCA). We
identify a compact X-ray source that appears to be the putative pulsar that
powers the nebula, and show that the X-ray spectrum of the nebula bears the
signature of synchrotron losses as particles diffuse into the outer nebula.
Using data from the Fermi LAT, we identify gamma-ray emission originating from
MSH 11-62. With density constraints from the new X-ray measurements of the
remnant, we model the evolution of the composite system in order to constrain
the properties of the underlying pulsar and the origin of the gamma-ray
emission.Comment: 12 Pages, 12 figures. Accepted for publication in the Astrophysical
Journa
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