4,928 research outputs found
The QUEST RR Lyrae Survey: III. The Low Galactic Latitude Catalogue
We present results for the QUEST RR Lyrae Survey at low galactic latitude,
conducted entirely with observations obtained with the QUEST mosaic camera and
the 1.0/1.5m J\"urgen Stock Schmidt telescope at the National Observatory of
Venezuela. The survey spans an area of 476 sq. deg on the sky, with multi-epoch
observations in the V, R and I photometric bands for 6.5x10^6 stars in the
galactic latitude range 30<= b(deg) <=+25, in a direction close to the Galactic
Anticenter 190<= l(deg)<= 230. The variability survey has a typical number of
30 observations per object in V and I and ~25 in R, with up to ~120-150 epochs
in V and I and up to ~100 in R in the best sampled regions. The completeness
magnitudes of the survey are V=R=18.5 mag, and I=18.0 mag. We identified 211 RR
Lyrae stars, 160 bona fide stars of type ab and 51 candidates of type c, ours
being the first deep RR Lyrae survey conducted at low galactic latitude.The
completeness of the RR Lyrae survey was estimated in >95 per cent and ~85 per
cent for RRab and RRc stars respectively. Photometric metallicities were
computed based on the light curves and individual extinctions calculated from
minimum light colours for each RRab star. Distances were obtained with typical
errors ~7 per cent. The RR Lyrae survey simultaneously spans a large range of
heliocentric distances 0.5<= R_hel(kpc)<=40 and heights above the plane
-15<=z(kpc)<=+20, with well known completeness across the survey area, making
it an ideal set for studying the struc ture of the Galactic thick disk.Comment: 24 pages, 17 figures, 8 tables. Accepted for publication in MNRA
The Academic Resilience Approach in the promotion of young people’s mental health. Proposals for its use in schools
Els joves que gaudeixen de bona salut mental són més propensos a tenir un rendiment acadèmic més bo i un millor desenvolupament social. Davant l’increment de problemes de salut mental entre adolescents a Catalunya, es presenta l’Enfocament de Resiliència Acadèmica (ERA) com una prà ctica estratègica per a centres d’educació secundà ria que involucra tota la comunitat educativa. La finalitat és ajudar que els joves, especialment els més vulnerables, aconsegueixin obtenir un rendiment acadèmic més òptim, malgrat les circumstà ncies en les quals es troben. Les propostes per integrar l’ERA als centres de secundà ria es basen en la redefinició de les activitats que ja es desenvolupen i en el disseny de noves prà ctiques educatives considerant els elements del Marc de Resiliència
Human Glucocorticoid Receptor β Regulates Gluconeogenesis and Inflammation in Mouse Liver
Whilein vitrostudies have demonstrated that a glucocorticoid receptor (GR) splice isoform, β-isoform of human GR (hGRβ), acts as a dominant-negative inhibitor of the classic hGRα and confers glucocorticoid resistance, thein vivofunction of hGRβ is poorly understood. To this end, we created an adeno-associated virus (AAV) to express hGRβ in the mouse liver under the control of the hepatocyte-specific promoter. Genome-wide expression analysis of mouse livers showed that hGRβ significantly increased the expression of numerous genes, many of which are involved in endocrine system disorders and the inflammatory response. Physiologically, hGRβ antagonized GRα's function and attenuated hepatic gluconeogenesis through downregulation of phosphoenolpyruvate carboxykinase (PEPCK) in wild-type (WT) mouse liver. Interestingly, however, hGRβ did not repress PEPCK in GR liver knockout (GRLKO) mice. In contrast, hGRβ regulates the expression of STAT1 in the livers of both WT and GRLKO mice. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays demonstrated that hGRβ binds to the intergenic glucocorticoid response element (GRE) of the STAT1 gene. Furthermore, treatment with RU486 inhibited the upregulation of STAT1 mediated by hGRβ. Finally, our array data demonstrate that hGRβ regulates unique components of liver gene expressionin vivoby both GRα-dependent and GRα-independent mechanisms
Effect of Spaceflight on the Isotonic Contractile Properties of Single Skeletal Muscle Fibers in the Rhesus Monkey
Connected Classroom Climate and Communication Apprehension: Correlations and Implications of the Basic Course
Although scholars have recommended increasing relational variables in the classroom such as familiarity, acquaintance level, and collaboration to help students moderate communication apprehension (CA), few, if any, academic studies have investigated the relationship between CA and a supportive climate among students in the college classroom. Self-report data were collected from 523 undergraduate students from a Midwestern university who participated in a large curriculum assessment program using the Connected Classroom Climate Inventory (CCCI) and the PRCA-24. Results showed significant relationships between student perceptions of connected-classroom climate and CA levels throughout the course
Accelerated Metastasis after Short-Term Treatment with a Potent Inhibitor of Tumor Angiogenesis
SummaryHerein we report that the VEGFR/PDGFR kinase inhibitor sunitinib/SU11248 can accelerate metastatic tumor growth and decrease overall survival in mice receiving short-term therapy in various metastasis assays, including after intravenous injection of tumor cells or after removal of primary orthotopically grown tumors. Acceleration of metastasis was also observed in mice receiving sunitinib prior to intravenous implantation of tumor cells, suggesting possible “metastatic conditioning” in multiple organs. Similar findings with additional VEGF receptor tyrosine kinase inhibitors implicate a class-specific effect for such agents. Importantly, these observations of metastatic acceleration were in contrast to the demonstrable antitumor benefits obtained when the same human breast cancer cells, as well as mouse or human melanoma cells, were grown orthotopically as primary tumors and subjected to identical sunitinib treatments
Suppressive impact of metronomic chemotherapy using UFT and/or cyclophosphamide on mediators of breast cancer dissemination and invasion
ProducciĂłn CientĂficaMetronomic chemotherapy using the 5-FU prodrug uracil-tegafur (UFT) and cyclophosphamide (CTX) was previously shown to only modestly delay primary tumor growth, but nevertheless markedly suppressed the development of micro-metastasis in an orthotopic breast cancer xenograft model, using the metastatic variant of the MDA-MB-231 cell line, 231/LM2-4. Furthermore, a remarkable prolongation of survival, with no toxicity, was observed in a model of postsurgical advanced metastatic disease. A question that has remained unanswered is the seemingly selective anti-metastatic mechanisms of action responsible for this treatment. We assessed the in vivo effect of metronomic UFT, CTX or their combination, on vascular density, collagen deposition and c-Met (cell mediators or modulators of tumor cell invasion or dissemination) via histochemistry/immunohistochemistry of primary tumor sections. We also assessed the effect of continuous exposure to low and non-toxic doses of active drug metabolites 5-fluorouracil (5-FU), 4-hydroperoxycyclophosphamide (4-HC) or their combination, on 231/LM2-4 cell invasiveness in vitro. In the in vivo studies, a significant reduction in vascular density and p-Met[Y1003] levels was associated with UFT+CTX treatment. All treatments reduced intratumoral collagen deposition. In the in vitro studies, a significant reduction of collagen IV invasion by all treatments was observed. The 3D structures formed by 231/LM2-4 on Matrigel showed a predominantly Mass phenotype under treated conditions and Stellate phenotype in untreated cultures. Taken together, the results suggest the low-dose metronomic chemotherapy regimens tested can suppress several mediators of tumor invasiveness highlighting a new perspective for the anti-metastatic efficacy of metronomic chemotherapy.Canadian Institutes of Health Research (grant 364411
Magnetic operations: a little fuzzy physics?
We examine the behaviour of charged particles in homogeneous, constant and/or
oscillating magnetic fields in the non-relativistic approximation. A special
role of the geometric center of the particle trajectory is elucidated. In
quantum case it becomes a 'fuzzy point' with non-commuting coordinates, an
element of non-commutative geometry which enters into the traditional control
problems. We show that its application extends beyond the usually considered
time independent magnetic fields of the quantum Hall effect. Some simple cases
of magnetic control by oscillating fields lead to the stability maps differing
from the traditional Strutt diagram.Comment: 28 pages, 8 figure
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