1,436 research outputs found
The disk around the brown dwarf KPNO Tau 3
We present submillimeter observations of the young brown dwarfs KPNO Tau 1,
KPNO Tau 3, and KPNO Tau 6 at 450 micron and 850 micron taken with the
Submillimeter Common-User Bolometer Array on the James Clerke Maxwell
Telescope. KPNO Tau 3 and KPNO Tau 6 have been previously identified as Class
II objects hosting accretion disks, whereas KPNO Tau 1 has been identified as a
Class III object and shows no evidence of circumsubstellar material. Our 3
sigma detection of cold dust around KPNO Tau 3 implies a total disk mass of
(4.0 +/- 1.1) x 10^{-4} Msolar (assuming a gas to dust ratio of 100:1). We
place tight constraints on any disks around KPNO Tau 1 or KPNO Tau 6 of <2.1 x
10^{-4} Msolar and <2.7 x 10^{-4} Msolar, respectively. Modeling the spectral
energy distribution of KPNO Tau 3 and its disk suggests the disk properties
(geometry, dust mass, and grain size distribution) are consistent with
observations of other brown dwarf disks and low-mass T-Tauri stars. In
particular, the disk-to-host mass ratio for KPNO Tau 3 is congruent with the
scenario that at least some brown dwarfs form via the same mechanism as
low-mass stars.Comment: 18 pages (preprint format), 3 figures, published in Ap
Investigation of flow conditions and the nature of the wall-constriction effect near and at choking by means of the hydraulic analogy
Classifications of Plane Continua
In the course of studying continua in the plane it has been asked if a given continuum has uncountably many disjoint duplications in the plane, and if so, what are the consequences of the existence of such a collection. The object of this paper is to study these problems and to develop some machinery useful in their resolution. In Section I, we review the definition of convergence and homeomorphic convergence of point sets in a metric space S. We then consider the space, π of all continuous functions from a compact metric space P to a separable metric space Q under the sup metric. The famous Borsuk Theorem [3], which shows that π is separable, is then proven. As a consequence of the separability of π , we show that in any uncountable collect ion G of compact sets in a separable metric space S, there must exist an element of G that is converged to by a sequence of elements of G. Furthermore, if the elements of Gare pairwise homeomorphic, then G contains an element which is converged to homeomorphically by some sequence in G. These theorems prove to be important in the study of disjoint embeddings of continua in separable metric spaces. In Section I, as throughout this paper, definitions are motivated and illustrated by numerous examples
Pin1 promotes GR transactivation by enhancing recruitment to target genes
The glucocorticoid receptor (GR) is a ligand activated transcription factor, serving to regulate both energy metabolism and immune functions. Factors that influence cellular sensitivity to glucocorticoids (GC) are therefore of great interest. The N-terminal of the GR contains numerous potential proline-directed phosphorylation sites, some of which can regulate GR transactivation. Unrestricted proline isomerisation can be inhibited by adjacent serine phosphorylation and requires a prolyl isomerise, Pin1. Pin1 therefore determines the functional outcome of proline-directed kinases acting on the GR, as cis/trans isomers are distinct pools with different interacting proteins. We show that Pin1 mediates GR transactivation, but not GR trans-repression. Two N-terminal GR serines, S203 and S211, are targets for Pin1 potentiation of GR transactivation, establishing a direct link between Pin1 and the GR. We also demonstrate GC-activated co-recruitment of GR and Pin1 to the GILZ gene promoter. The Pin1 effect required both its WW and catalytic domains, and GR recruitment to its GRE was Pin1-dependent. Therefore, Pin1 is a selective regulator of GR transactivation, acting through N-terminal phospho-serine residues to regulate GR recruitment to its target sites in the genome. As Pin1 is dysregulated in disease states, this interaction may contribute to altered GC action in inflammatory conditions
Supporting Nursing Leadership by the Implementation of an increased Supervisory Role
Clinical nurse leadership is essential for the provision of high quality patient care. Recent research has highlighted the need for all Senior Charge Nurses (SCNs) to be equipped to deliver effective ward management, staff development and ultimately a positive patient experience. The provision of ‘supervisory hours’ is a vital component of an SCN role, enabling the effective leadership of their teams. This paper describes the increased supervisory role implemented by the Leading Better Care program within one Health Board area of Scotland. Mixed methods research (online survey n=52 and in-depth qualitative interviews n=12) explored the experiences of SCNs using their increased supervisory time and its perceived impact on clinical practice. Findings demonstrate that increased supervisory time positively impacted several key areas of clinical practice. Although the increased supervisory role empowered SCNs and promoted their professional development, they require greater role clarity, managerial support and leadership development to reduce role stress and promote future career aspirations
Determination of genomic DNA sequences for beta-tubulin isotype 1 from multiple species of cyathostomin and detection of resistance alleles in third-stage larvae from horses with naturally acquired infections
An abnormality in glucocorticoid receptor expression differentiates steroid responders from nonresponders in keloid disease
Background: Glucocorticoids (GCs) are first-line treatment for keloid disease (KD) but are limited by high incidence of resistance, recurrence and undesirable sideeffects. Identifying patient responsiveness early could guide therapy. Methods: Nineteen patients with KD were recruited at week 0 (before treatment) and received intralesional steroids. At weeks 0, 2 and 4, noninvasive imaging and biopsies were performed. Responsiveness was determined by clinical response and a significant reduction in vascular perfusion following steroid treatment, using full-field laser perfusion imaging (FLPI). Responsiveness was also evaluated using (i) spectrophotometric intracutaneous analysis to quantify changes in collagen and melanin and (ii) histology to identify changes in epidermal thickness and glycosaminoglycan (GAG) expression. Biopsies were used to quantify changes in glucocorticoid receptor (GR) expression using quantitative reverse transcriptase polymerase chain reaction, immunoblotting and immunohistochemistry. Results: At week 2, the FLPI was used to separate patients into steroid responsive (n = 12) and nonresponsive groups (n = 7). All patients demonstrated a signifccant decrease in GAG at week 2 (P < 0 05). At week 4, responsive patients exhibited significant reduction in melanin, GAG, epidermal thickness (all P < 0 05) and a continued reduction in perfusion (P < 0 001) compared with nonresponders. Steroid-responsive patients had increased GR expression at baseline and showed autoregulation of GR compared with nonresponders, who showed no change in GR transcription or protein. Conclusions: This is the first demonstration that keloid response to steroids can be measured objectively using noninvasive imaging. FLPI is a potentially reliable tool to stratify KD responsiveness. Altered GR expression may be the mechanism gating therapeutic response
Automated Discovery of Flight Track Anomalies
As new technologies are developed to handle the complexities of the Next Generation Air Transportation System (NextGen), it is increasingly important to address both current and future safety concerns along with the operational, environmental, and efficiency issues within the National Airspace System (NAS). In recent years, the Federal Aviation Administrations (FAA) safety offices have been researching ways to utilize the many safety databases maintained by the FAA, such as those involving flight recorders, radar tracks, weather, and many other high- volume sensors, in order to monitor this unique and complex system. Although a number of current technologies do monitor the frequency of known safety risks in the NAS, very few methods currently exist that are capable of analyzing large data repositories with the purpose of discovering new and previously unmonitored safety risks. While monitoring the frequency of known events in the NAS enables mitigation of already identified problems, a more proactive approach of finding unidentified issues still needs to be addressed. This is especially important in the proactive identification of new, emergent safety issues that may result from the planned introduction of advanced NextGen air traffic management technologies and procedures. Development of an automated tool that continuously evaluates the NAS to discover both events exhibiting flight characteristics indicative of safety-related concerns as well as operational anomalies will heighten the awareness of such situations in the aviation community and serve to increase the overall safety of the NAS. This paper discusses the extension of previous anomaly detection work to identify operationally significant flights within the highly complex airspace encompassing the New York area of operations, focusing on the major airports of Newark International (EWR), LaGuardia International (LGA), and John F. Kennedy International (JFK). In addition, flight traffic in the vicinity of Denver International (DEN) airport/airspace is also investigated to evaluate the impact on operations due to variances in seasonal weather and airport elevation. From our previous research, subject matter experts determined that some of the identified anomalies were significant, but could not reach conclusive findings without additional supportive data. To advance this research further, causal examination using domain experts is continued along with the integration of air traffic control (ATC) voice data to shed much needed insight into resolving which flight characteristic(s) may be impacting an aircraft's unusual profile. Once a flight characteristic is identified, it could be included in a list of potential safety precursors. This paper also describes a process that has been developed and implemented to automatically identify and produce daily reports on flights of interest from the previous day
Loss of Glucocorticoid Receptor Expression by DNA Methylation Prevents Glucocorticoid Induced Apoptosis in Human Small Cell Lung Cancer Cells
Human small cell lung cancer (SCLC) is highly aggressive, and quickly develops resistance to therapy. SCLC cells are typically insensitive to glucocorticoids due to impaired glucocorticoid receptor (GR) expression. This is important as we have previously shown that expression of a GR transgene induces cell death in-vitro, and inhibits tumor growth in-vivo. However, the underlying mechanism for loss of GR expression is unknown. The SCLC cell line, DMS79, has low GR expression, compared to non-SCLC cell lines and normal bronchial epithelial cells. Retroviral GR expression in DMS79 cells caused activation of the apoptotic pathway as evidenced by marked induction of caspase-3 activity. Methylation analysis of the GR promoter revealed some methylation in the 1D, and 1E promoters of the GR gene, however the ubiquitous constitutively active 1C promoter was heavily methylated. In the 1C promoter there was a highly significant increase in DNA methylation in a panel of 14 human SCLC cell lines compared to a mixed panel of GR expressing, and non-expressing cell lines, and to peripheral blood mononuclear cells. Furthermore, within the panel of SCLC cell lines there was a significant negative correlation seen between methylation of the 1C promoter, and GR protein expression. Reversal of GR gene methylation with DNA methyltransferase inhibition caused increased GR mRNA and protein expression in SCLC but not non-SCLC cells. This resulted in increased Gc sensitivity, decreased Bcl-2 expression and increased caspase-3 activity in SCLC cells. These data suggest that DNA methylation decreases GR gene expression in human SCLC cells, in a similar manner to that for conventional tumor suppressor genes
A Dual-Channel Optical Brain-Computer Interface In A Gaming Environment
This paper explores the viability of using a novel optical
Brain-Computer Interface within a gaming environment.
We describe a system that incorporates a 3D gaming
engine and an optical BCI. This made it possible to
classify activation in the motor cortex within a synchronous
experimental paradigm. Detected activations were
used to control the arm movement of a human model in
the graphical engine
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