482 research outputs found
Translocation as a strategy to rehabilitate the queen conch (Strombus gigas) population in the Florida Keys
Queen conch (Strombus gigas) stocks in the Florida Keys once supported commercial and recreational fisheries, but overharvesting has decimated this once abundant snail. Despite a ban on harvesting this species since 1985, the local conch population has not recovered. In addition, previous work has reported that conch located in nearshore Keys waters are incapable of spawning because of poor gonadal condition, although reproduction does occur offshore. Queen conch in other areas undergo ontogenetic migrations from shallow, nearshore sites to offshore habitats, but conch in the Florida Keys are prevented from doing so by Hawk Channel. The present study was initiated to determine the potential of translocating nonspawning nearshore conch to offshore sites in order to augment the spawning stock. We translocated adult conch from two nearshore sites to two offshore sites. Histological examinations at the initiation of this study confirmed that nearshore conch were incapable of reproduction, whereas offshore conch had normal gonads and thus were able to reproduce. The gonads of nearshore females were in worse condition than those of nearshore males. However, the gonadal condition of the translocated nearshore conch improved, and these animals began spawning after three months offshore. This finding suggests that some component of the nearshore environment (e.g., pollutants, temperature extremes, poor food or habitat quality) disrupts reproduction in conch, but that removal of nearshore animals to suitable offshore habitat can restore reproductive viability. These results indicate that translocations are preferable to releasing hatchery-reared juveniles because they are more cost-effective, result in a more rapid increase in reproductive output, and maintain the genetic integrity of the wild stock. Therefore, translocating nearshore conch to offshore spawning aggregations may be the key to expediting the recovery of queen conch stocks in the Florida Keys
Immune Reactivity and Pseudoprogression or Tumor Flare in a Serially Biopsied Neuroendocrine Patient Treated with the Epigenetic Agent RRx-001.
Neuroendocrine tumors (NETs) are grouped together as a single class on the basis of histologic appearance, immunoreactivity for the neuroendocrine markers chromogranin A and synaptophysin, and potential secretion of hormones, neurotransmitters, neuromodulators and neuropeptides. Nevertheless, despite these common characteristics, NETs differ widely in terms of their natural histories: high-grade NETs are clinically aggressive and, like small cell lung cancer, which they most closely resemble, tend to respond to cisplatin and etoposide. In contrast, low-grade NETs, which as a rule progress and behave indolently, do not. In either case, the treatment strategy, apart from potentially curative surgical resection, is very poorly defined. This report describes the case of a 28-year-old white male with a diagnosis of high-grade NET of undetermined primary site metastatic to the lymph nodes, skin and paraspinal soft tissues, treated with the experimental anticancer agent RRx-001, in the context of a phase II clinical trial called TRIPLE THREAT (NCT02489903); serial sampling of tumor material through repeat biopsies demonstrated an intratumoral inflammatory response, including the amplification of infiltrating T cells, which correlated with clinical and symptomatic benefit. This case suggests that pseudoprogression or RRx-001-induced enlargement of tumor lesions, which has been previously described for several RRx-001-treated patients, is the result of tumoral lymphocyte infiltration
Association of ventricular arrhythmia and in-hospital mortality in stroke patients in Florida: A nonconcurrent prospective study
Stroke remains one of the leading causes of death in the United States. Current evidence identified electrocardiographic abnormalities and cardiac arrhythmias in 50% of patients with an acute stroke. The purpose of this study was to assess whether the presence of ventricular arrhythmia (VA) in adult patients hospitalized in Florida with acute stroke increased the risk of in-hospital mortality. Secondary data analysis of 215,150 patients with ischemic and hemorrhagic stroke hospitalized in the state of Florida collected by the Florida Agency for Healthcare Administration from 2008 to 2012. The main outcome for this study was in-hospital mortality. The main exposure of this study was defined as the presence of VA. VA included the ICD-9 CM codes: paroxysmal ventricular tachycardia (427.1), ventricular fibrillation (427.41), ventricular flutter (427.42), ventricular fibrillation and flutter (427.4), and other – includes premature ventricular beats, contractions, or systoles (427.69). Differences in demographic and clinical characteristics and hospital outcomes were assessed between patients who developed versus did not develop VA during hospitalization (χ2 and t tests). Binary logistic regression was used to estimate unadjusted and adjusted odds ratios and 95% confidence intervals (CIs) between VA and in-hospital mortality. VA was associated with an increased risk of in-hospital mortality after adjusting for all covariates (odds ratio [OR]: 1.75; 95% CI: 1.6–1.2). There was an increased in-hospital mortality in women compared to men (OR: 1.1; 95% CI: 1.1–1.14), age greater than 85 years (OR: 3.9, 95% CI: 3.5–4.3), African Americans compared to Whites (OR: 1.1; 95% CI: 1.04–1.2), diagnosis of congestive heart failure (OR: 2.1; 95% CI: 2.0–2.3), and atrial arrhythmias (OR: 2.1, 95% CI: 2.0–2.2). Patients with hemorrhagic stroke had increased odds of in-hospital mortality (OR: 9.0; 95% CI: 8.6–9.4) compared to ischemic stroke. Identifying VAs in stroke patients may help in better target at risk populations for closer cardiac monitoring during hospitalization. The impact of implementing methods of quick assessment could potentially reduce VA associated sudden cardiac death
Two Types of X-ray Spectra in Cataclysmic Variables
We present Chandra HETG spectra of seven cataclysmic variables. We find that
they divide unambiguously into two distinct types. Spectra of the first type
are remarkably well fit by a simple cooling flow model, which assumes only
steady-state isobaric radiative cooling. The maximum temperature and the
normalization, which provides a highly precise measurement of the accretion
rate, are the only free parameters of this model. Spectra of the second type
are grossly inconsistent with a cooling flow model. They instead exhibit a hard
continuum, and show strong H-like and He-like ion emission but little Fe
L-shell emission, which is consistent with expectations for line emission from
a photoionized plasma. Using a simple photoionization model, we argue that the
observed line emission for these sources can be driven entirely by the hard
continuum. The physical significance of these two distinct types of X-ray
spectra is also explored.Comment: 12 pages including 2 color figures, accepted for publication in
Astrophysical Journal Letter
Visualizing Heavy Fermion Confinement and Pauli-Limited Superconductivity in Layered CeCoIn5
Layered material structures play a key role in enhancing electron-electron
interactions to create correlated metallic phases that can transform into
unconventional superconducting states. The quasi-two-dimensional electronic
properties of such compounds are often inferred indirectly through examination
of their bulk properties. Here we use scanning tunneling microscopy and
spectroscopy to directly probe in cross section the quasi-two-dimensional
correlated electronic states of the heavy fermion superconductor CeCoIn5. Our
measurements reveal the strong confined nature of heavy quasi-particles,
anisotropy of tunneling characteristics, and layer-by-layer modulated behavior
of the precursor pseudogap gap phase in this compound. Examining the interlayer
coupled superconducting state at low temperatures, we find that the orientation
of line defects relative to the d-wave order parameter determines whether
in-gap states form due to scattering. Spectroscopic imaging of the anisotropic
magnetic vortex cores directly characterizes the short interlayer
superconducting coherence length and shows an electronic phase separation near
the upper critical in-plane magnetic field, consistent with a Pauli-limited
first-order phase transition into a pseudogap phase
Multi-epoch X-ray observations of the Seyfert 1.2 galaxy Mrk 79: bulk motion of the illuminating X-ray source
Multi-epoch X-ray spectroscopy (0.3-25 keV) of the Seyfert 1.2 galaxy Mrk 79
(UGC 3973) spanning nearly eight years and a factor of three in broadband flux
are analysed. The data are obtained at seven epochs with either XMM-Newton or
Suzaku. Comparison with contemporaneous RXTE monitoring indicate that all flux
states of Mrk 79 are represented by the data. The spectra are fitted in a
self-consistent manner adopting a power law and ionised reflection to describe
the broadband continuum. Modification of the spectra by a distant photoionised
medium, seen predominantly in emission, are also included. Under the assumption
that the inner disk is at the innermost stable circular orbit, our blurred
reflection models give a spin of a = 0.7+/-0.1. The reflection component in
each spectrum is weaker than predicted by simple reflection models. If the
illuminating X-ray emission is produced by flares above the disk that move at
mildly relativistic velocities, however, diminished reflection is expected.
Light bending due to strong gravity near black holes can influence how the
illuminating and reflected flux are observed; variations in Mrk 79 do not
suggest that light bending is important in this source.Comment: 13 pages. Accepted for publication in MNRA
First Light Measurements with the XMM-Newton Reflection Grating Spectrometers: Evidence for an Inverse First Ionisation Potential Effect and Anomalous Ne A bundance in the Coronae of HR 1099
The RS CVn binary system HR 1099 was extensively observed by the XMM-Newton
observatory in February 2000 as its first-light target. A total of 570 ks of
exposure time was accumulated with the Reflection Grating Spectrometers (RGS).
The integrated X-ray spectrum between 5-35 Angstrom is of unprecedented quality
and shows numerous features attributed to transitions of the elements C, N, O,
Ne, Mg, Si, S, Fe, and Ni. We perform an in-depth study of the elemental
composition of the average corona of this system, and find that the elemental
abundances strongly depend on the first ionisation potential (FIP) of the
elements. But different from the solar coronal case, we find an inverse FIP
effect, i.e., the abundances (relative to oxygen) increase with increasing FIP.
Possible scenarios, e.g., selective enrichment due to Ne-rich flare-like
events, are discussed.Comment: 5 pages, 4 figures. Accepted by A&A Letters, XMM issu
Early satellite cell communication creates a permissive environment for long-term muscle growth
Using in vivo muscle stem cell (satellite cell)-specific extracellular vesicle (EV) tracking, satellite cell depletion, in vitro cell culture, and single-cell RNA sequencing, we show satellite cells communicate with other cells in skeletal muscle during mechanical overload. Early satellite cell EV communication primes the muscle milieu for proper long-term extracellular matrix (ECM) deposition and is sufficient to support sustained hypertrophy in adult mice, even in the absence of fusion to muscle fibers. Satellite cells modulate chemokine gene expression across cell types within the first few days of loading, and EV delivery of miR 206 to fibrogenic cells represses Wisp1 expression required for appropriate ECM remodeling. Late-stage communication from myogenic cells during loading is widespread but may be targeted toward endothelial cells. Satellite cells coordinate adaptation by influencing the phenotype of recipient cells, which extends our understanding of their role in muscle adaptation beyond regeneration and myonuclear donation
The Dictyostelium type V myosin MyoJ is responsible for the cortical association and motility of contractile vacuole membranes
The contractile vacuole (CV) complex in Dictyostelium is a tubulovesicular osmoregulatory organelle that exhibits extensive motility along the actin-rich cortex, providing a useful model for investigating myosin-dependent membrane transport. Here, we show that the type V myosin myoJ localizes to CV membranes and is required for efficient osmoregulation, the normal accumulation of CV membranes in the cortex, and the conversion of collapsed bladder membranes into outwardly radiating cortical CV tubules. Complementation of myoJ-null cells with a version of myoJ containing a shorter lever arm causes these radiating tubules to move at a slower speed, confirming myoJ's role in translocating CV membranes along the cortex. MyoJ-null cells also exhibit a dramatic concentration of CV membranes around the microtubule-organizing center. Consistently, we demonstrate that CV membranes also move bi-directionally on microtubules between the cortex and the centrosome. Therefore, myoJ cooperates with plus and minus end–directed microtubule motors to drive the normal distribution and dynamics of the CV complex in Dictyostelium
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