4,611 research outputs found
Hard Thermal Loops, Gauged WZNW Action and the Energy of Hot Quark-Gluon Plasma
The generating functional for hard thermal loops in QCD is rewritten in terms
of a gauged WZNW action by introducing an auxiliary field. This shows in a
simple way that the contribution of hard thermal loops to the energy of the
quark-gluon plasma is positive.Comment: 9 pages, CU-TP 60
Unveiling the Active Nucleus of Centaurus A
We report new HST WFPC2 and NICMOS observations of the center of the nearest
radio galaxy Centaurus A (NGC 5128) and discuss their implications for our
understanding of the active nucleus and jet. We detect the active nucleus in
the near-IR (K and H) and, for the first time, in the optical (I and V),
deriving the spectral energy distribution of the nucleus from the radio to
X-rays. The optical and part of the near-IR emission can be explained by the
extrapolation of the X-ray power law reddened by A_V~14mag, a value consistent
with other independent estimates.
The 20pc-scale nuclear disk discovered by Schreier et al. (1998) is detected
in the [FeII] 1.64mic line and presents a morphology similar to that observed
in Pa alpha with a [FeII]/Pa alpha ratio typical of low ionization Seyfert
galaxies and LINERs. NICMOS 3 Pa alpha observations in a 50"x50" circumnuclear
region suggest enhanced star formation (~0.3Msun/yr) at the edges of the
putative bar seen with ISO, perhaps due to shocks driven into the gas.
The light profile, reconstructed from V, H and K observations, shows that
Centaurus A has a core profile with a resolved break at ~4" and suggests a
black--hole mass of ~10^9 Msun. A linear blue structure aligned with the
radio/X-ray jet may indicate a channel of relatively low reddening in which
dust has been swept away by the jet.Comment: 19 pages, 13 figures, Astrophysical Journal, in press. High quality
figures available at http://www.arcetri.astro.it/~marconi/colpic.htm
Adjuvants : an essential component of neisseria vaccines
Adjuvants may be classified into delivery systems and immune potentiator or modulator molecules based on their mechanism of action. Neisseria vaccines containing traditional adjuvants such as aluminium salts have existed for long time, but meningitis caused by Neisseria meningitidis serogroups, particularly serogroup B, continues to be a global health problem. Novel strategies have applied in silico and recombinant technologies to develop "universal" antigens (e.g. proteins, peptides and plasmid DNA) for vaccines, but these antigens have been shown to be poorly immunogenic even when alum adjuvanted, implying a need for better vaccine design. In this work we review the use of natural, detoxified, or synthetic molecules in combination with antigens to activate the innate immune system and to modulate the adaptive immune responses. In the main, antigenic and imune potentiator signals are delivered using nano-, micro-particles, alum, or emulsions. The importance of interaction between adjuvants and antigens to activate and target dendritic cells, the bridge between the innate and adaptive immune systems, will be discussed. In addition, nasal vaccine strategies based on the development of mucosal adjuvants and Neisseria derivatives to eliminate the pathogen at the site of infection provide promising adjuvants effective not only against respiratory pathogens, but also against pathogens responsible for enteric and sexually transmitted diseases
A Comparison of Spectroscopic versus Imaging Techniques for Detecting Close Companions to Kepler Objects of Interest
(Abbreviated) Kepler planet candidates require both spectroscopic and imaging
follow-up observations to rule out false positives and detect blended stars.
[...] In this paper, we examine a sample of 11 Kepler host stars with
companions detected by two techniques -- near-infrared adaptive optics and/or
optical speckle interferometry imaging, and a new spectroscopic deblending
method. We compare the companion Teff and flux ratios (F_B/F_A, where A is the
primary and B is the companion) derived from each technique, and find no cases
where both companion parameters agree within 1sigma errors. In 3/11 cases the
companion Teff values agree within 1sigma errors, and in 2/11 cases the
companion F_B/F_A values agree within 1sigma errors. Examining each Kepler
system individually considering multiple avenues (isochrone mapping, contrast
curves, probability of being bound), we suggest two cases for which the
techniques most likely agree in their companion detections (detect the same
companion star). Overall, our results support the advantage the spectroscopic
deblending technique has for finding very close-in companions (0.02-0.05") that are not easily detectable with imaging. However, we
also specifically show how high-contrast AO and speckle imaging observations
detect companions at larger separations (0.02-0.05") that are
missed by the spectroscopic technique, provide additional information for
characterizing the companion and its potential contamination (e.g., PA,
separation, m), and cover a wider range of primary star effective
temperatures. The investigation presented here illustrates the utility of
combining the two techniques to reveal higher-order multiples in known
planet-hosting systems.Comment: Accepted to AJ. 40 pages, 12 figure
Observations préliminaires sur les insectes nuisibles à l'araza (Eugenia stipitata McVaugh, Myrtaceae), nouvelle culture fruitière en Amazonie
L'araza (#Eugenia stipitata McVaugh, #Myrtaceae) est un arbuste fruitier amazonien récemment domestiqué, qui présente un fort potentiel agro-industriel. Afin d'inventorier les insectes nuisibles, des évaluations ont été entreprises entre 1988 et 1992 dans les plantations de trois centres de recherche et dans deux plantations privées, proches d'Iquitos, en Amazonie péruvienne. Neuf espèces nuisibles ont été identifiées dont cinq affectent les fruits, trois sont des défoliateurs et la dernière coupe les rameaux. Quatre de ces espèces sont considérées comme nuisibles : #Anastrepha obliqua, #Conotrachelus eugeniae et #Atractomerus immigrans, qui influent sur la qualité et le volume des fruits récoltés ainsi que #Plectrophoroides impressicollis qui peut détruire totalement les inflorescences. (Résume d'auteur
Hard Thermal Loops, Static Response and the Composite Effective Action
First, we investigate the static non-Abelian Kubo equation. We prove that it
does not possess finite energy solutions; thereby we establish that gauge
theories do not support hard thermal solitons. A similar argument shows that
"static" instantons are absent. In addition, we note that the static equations
reproduce the expected screening of the non-Abelian electric field by a gauge
invariant Debye mass m=gT sqrt((N+N_F/2)/3). Second, we derive the non-Abelian
Kubo equation from the composite effective action. This is achieved by showing
that the requirement of stationarity of the composite effective action is
equivalent, within a kinematical approximation scheme, to the condition of
gauge invariance for the generating functional of hard thermal loops.Comment: 17 pages, MIT preprint CTP#2261. An Appendix [including one
(appended) PS figure] presenting a numerical analysis of the static solutions
has been included. A note relating our approach to alternative ones has been
added. We have also added references and comments in Section II
Chaplygin gas with non-adiabatic pressure perturbations
Perturbations in a Chaplygin gas, characterized by an equation of state , may acquire non-adiabatic contributions if spatial variations of the
parameter are admitted. This feature is shown to be related to a specific
internal structure of the Chaplygin gas. We investigate how perturbations of
this type modify the adiabatic sound speed and influence the time dependence of
the gravitational potential which gives rise to the Integrated Sachs-Wolfe
effect in the anisotropy spectrum of the cosmic microwave background.Comment: 16 pages, comments and references added, accepted for publication in
Class.Quantum Gra
Binding of Antitumor Ruthenium(III) Complexes to Plasma Proteins
Presently, there is large interest in analysing the interactions in vitro with plasma proteins of some novel antitumor ruthenium(III) complexes that are in preclinical or clinical phase. The joint application of separation and spectroscopic techniques provides valuable information on the nature and the properties of the resulting ruthenium/protein adducts. Recent work carried out in our laboratory points out that, under physiological conditions, some selected ruthenium(III) complexes bind plasma proteins tightly with a marked preference for surface imidazole groups. Representative examples of interactions of antitumor ruthenium(III) complexes with plasma proteins such as albumin and transferrin are given. Notably the antitumor ruthenium(III) complexes considered here bind proteins much tighter than DNA; it is proposed that protein binding of ruthenium(III) complexes will have a large impact on the biodistribution, the pharmacokinetics and the mechanism of action of these experimental drugs
45 Senolytic Therapy Transiently Reduces Inflammatory Markers in Primary Blood Mononuclear Cells of Individuals with Early Alzheimer’s Disease: Exploring the Conserved Transcriptional Response to Adversity as a Biomarker for Disease State
OBJECTIVES/GOALS: Determine if the Conserved Transcriptional Response to Adversity transcriptomic profile established in primary blood mononuclear cells (PBMC) of chronically stress caregivers, is present in individuals with early Alzheimer’s disease. Chronic stress is a risk factor for Alzheimer’s, and may be an untapped biomarker for disease risk and pathology.
METHODS/STUDY POPULATION: To collect preliminary data on the Conserved Transcriptional Response to Adversity profile in individuals with Alzheimer’s disease, we were able to utilize primary blood mononuclear cell samples from a small open label pilot study called Senolytic Therapy to Modulate the Progression of Alzheimer’s Disease, designed to clear stressed senescent cells. We hypothesized senolytics may beneficially reverse this stress profile. We developed a NanoString assay (measuring 19 inflammatory, 31 type-1 interferon, and 3 antibody synthesis genes) to compare these transcriptomic changes within 4 individuals measured at baseline, post-treatment with an intermittent 12-week senolytic therapy, and at an optional extended post-treatment follow-up time point \u3e 3 months after their post treatment visit.
RESULTS/ANTICIPATED RESULTS: There was relative downregulation of expression in transcription in 7 of 19 measured inflammatory genes (FOS, PTGS2, IL8, FOS, Il1b, JUNB, and JUN) in Alzheimer’s disease participants after receiving senolytic treatment (baseline vs. post-treatment). This is consistent with a decrease in the inflammatory arm of the Conserved Transcriptional Response to Adversity profile. These differences were not significant between baseline and the extended follow-up, indicative of a transient effect of senolytic. There were no changes in type 1 interferon or antibody synthesis genes. This data provides preliminary evidence for larger controlled studies to further establish this profile in Alzheimer’s disease, providing exciting evidence for transcript changes that may be reproducible with senolytic therapy.
DISCUSSION/SIGNIFICANCE: Literature relevant to Alzheimer’s disease indicates global increases in inflammation paired with deficits in immune response, capturing some genes associated with the Conserved Transcriptional Response to Adversity. This profile may be a useful biomarker for prediction of disease severity or risk of dementia due to chronic stress
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