249 research outputs found
IRIS: A new generation of IRAS maps
The Infrared Astronomical Satellite (IRAS) had a tremendous impact on many
areas of modern astrophysics. In particular it revealed the ubiquity of
infrared cirrus that are a spectacular manifestation of the interstellar medium
complexity but also an important foreground for observational cosmology. With
the forthcoming Planck satellite there is a need for all-sky complementary data
sets with arcminute resolution that can bring informations on specific
foreground emissions that contaminate the Cosmic Microwave Background
radiation. With its 4 arcmin resolution matching perfectly the high-frequency
bands of Planck, IRAS is a natural data set to study the variations of dust
properties at all scales. But the latest version of the images delivered by the
IRAS team (the ISSA plates) suffer from calibration, zero level and striping
problems that can preclude its use, especially at 12 and 25 micron. In this
paper we present how we proceeded to solve each of these problems and enhance
significantly the general quality of the ISSA plates in the four bands (12, 25,
60 and 100 micron). This new generation of IRAS images, called IRIS, benefits
from a better zodiacal light subtraction, from a calibration and zero level
compatible with DIRBE, and from a better destriping. At 100 micron the IRIS
product is also a significant improvement from the Schlegel et al. (1998) maps.
IRIS keeps the full ISSA resolution, it includes well calibrated point sources
and the diffuse emission calibration at scales smaller than 1 degree was
corrected for the variation of the IRAS detector responsivity with scale and
brightness. The uncertainty on the IRIS calibration and zero level are
dominated by the uncertainty on the DIRBE calibration and on the accuracy of
the zodiacal light model.Comment: 16 pages, 17 figures, accepted for publication in ApJ (Suppl). Higher
resolution version available at
http://www.cita.utoronto.ca/~mamd/IRIS/IrisTechnical.htm
Revisión radiocarbónica y cronocultural del Neolítico antiguo de la Balma Margineda (Aixovall, Andorra)
This work discusses the radiocarbon evidence from the Neolithic layers of the Balma Margineda (Andorra). Since the last excavation campaigns during the ‘90s, a total of ten 14C dates has been obtained. We discuss their stratigraphic provenance and suggest that only three of the ten 14C dates should be considered reliable. The new dates assign the Neolithic occupations to a more recent chronology. Moreover, we also present a brief revision of the ceramic and lithic materials from the in situ Neolithic layers, in order reinterpret the site using the most recent data on the Early Neolithic of Pyrenean region
FIRBACK Source Counts and Cosmological Implications
FIRBACK is a one of the deepest surveys performed at 170 microns with ISOPHOT
onboard ISO, and is aimed at the study of cosmic far infrared background
sources. About 300 galaxies are detected in an area of four square degrees, and
source counts present a strong slope of 2.2 on an integral "logN-logS" plot,
which cannot be due to cosmological evolution if no K-correction is present.
The resolved sources account for less than 10% of the Cosmic Infrared
Background at 170 microns. In order to understand the nature of the sources
contributing to the CIB, and to explain deep source counts at other
wavelengths, we have developed a phenomenological model, which constrains in a
simple way the luminosity function evolution with redshift, and fits all the
existing deep source counts from the mid-infrared to the submillimetre range.
Images, materials and papers available on the FIRBACK web:
http://wwwfirback.ias.u-psud.fr wwwfirback.ias.u-psud.frComment: proceedings of "ISO Surveys of a Dusty Universe", eds. D. Lemke, M.
Stickel, K. Wilke, Ringberg, 8-12 Nov 1999, to appear in Springer 'Lecture
Notes of Physics'. 8 pages, 7 eps figures, .sty include
FIRBACK Source Counts and Cosmological Implications
FIRBACK is a one of the deepest surveys performed at 170 microns with ISOPHOT
onboard ISO, and is aimed at the study of cosmic far infrared background
sources. About 300 galaxies are detected in an area of four square degrees, and
source counts present a strong slope of 2.2 on an integral "logN-logS" plot,
which cannot be due to cosmological evolution if no K-correction is present.
The resolved sources account for less than 10% of the Cosmic Infrared
Background at 170 microns. In order to understand the nature of the sources
contributing to the CIB, and to explain deep source counts at other
wavelengths, we have developed a phenomenological model, which constrains in a
simple way the luminosity function evolution with redshift, and fits all the
existing deep source counts from the mid-infrared to the submillimetre range.
Images, materials and papers available on the FIRBACK web:
http://wwwfirback.ias.u-psud.fr wwwfirback.ias.u-psud.frComment: proceedings of "ISO Surveys of a Dusty Universe", eds. D. Lemke, M.
Stickel, K. Wilke, Ringberg, 8-12 Nov 1999, to appear in Springer 'Lecture
Notes of Physics'. 8 pages, 7 eps figures, .sty include
Neolithic genomic data from southern France showcase intensified interactions with hunter-gatherer communities
SummaryArchaeological research shows that the dispersal of the Neolithic took a more complex turn when reaching western Europe, painting a contrasted picture of interactions between autochthonous hunter-gatherers (HGs) and incoming farmers. In order to clarify the mode, the intensity, and the regional variability of biological exchanges implied in these processes, we report new palaeogenomic data from Occitanie, a key region in Southern France. Genomic data from 28 individuals originating from six sites spanning from c. 5,500 to c. 2,500 BCE allow us to characterize regional patterns of ancestries throughout the Neolithic period. Results highlight major differences between the Mediterranean and Continental Neolithic expansion routes regarding both migration and interaction processes. High proportions of HG ancestry in both Early and Late Neolithic groups in Southern France support multiple pulses of inter-group gene flow throughout time and space and confirm the need for regional studies to address the complexity of the processes involved
ApoA-I Deficiency Increases Cortical Amyloid Deposition, Cerebral Amyloid Angiopathy, Cortical and Hippocampal Astrogliosis, and Amyloid-associated Astrocyte Reactivity in APP/PS1 Mice
Background
Alzheimer’s disease (AD) is defined by amyloid beta (Aβ) plaques and neurofibrillary tangles and characterized by neurodegeneration and memory loss. The majority of AD patients also have Aβ deposition in cerebral vessels known as cerebral amyloid angiopathy (CAA), microhemorrhages, and vascular co-morbidities, suggesting that cerebrovascular dysfunction contributes to AD etiology. Promoting cerebrovascular resilience may therefore be a promising therapeutic or preventative strategy for AD. Plasma high-density lipoproteins (HDL) have several vasoprotective functions and are associated with reduced AD risk in some epidemiological studies and with reduced Aβ deposition and Aβ-induced inflammation in 3D engineered human cerebral vessels. In mice, deficiency of apoA-I, the primary protein component of HDL, increases CAA and cognitive dysfunction, whereas overexpression of apoA-I from its native promoter in liver and intestine has the opposite effect and lessens neuroinflammation. Similarly, acute peripheral administration of HDL reduces soluble Aβ pools in the brain and some studies have observed reduced CAA as well. Here, we expand upon the known effects of plasma HDL in mouse models and in vitro 3D artery models to investigate the interaction of amyloid, astrocytes, and HDL on the cerebrovasculature in APP/PS1 mice. Methods
APP/PS1 mice deficient or hemizygous for Apoa1 were aged to 12 months. Plasma lipids, amyloid plaque deposition, Aβ protein levels, protein and mRNA markers of neuroinflammation, and astrogliosis were assessed using ELISA, qRT-PCR, and immunofluorescence. Contextual and cued fear conditioning were used to assess behavior. Results
In APP/PS1 mice, complete apoA-I deficiency increased total and vascular Aβ deposition in the cortex but not the hippocampus compared to APP/PS1 littermate controls hemizygous for apoA-I. Markers of both general and vascular neuroinflammation, including Il1b mRNA, ICAM-1 protein, PDGFRβ protein, and GFAP protein, were elevated in apoA-I-deficient APP/PS1 mice. Additionally, apoA-I-deficient APP/PS1 mice had elevated levels of vascular-associated ICAM-1 in the cortex and hippocampus and vascular-associated GFAP in the cortex. A striking observation was that astrocytes associated with cerebral vessels laden with Aβ or associated with Aβ plaques showed increased reactivity in APP/PS1 mice lacking apoA-I. No behavioral changes were observed. Conclusions
ApoA-I-containing HDL can reduce amyloid pathology and astrocyte reactivity to parenchymal and vascular amyloid in APP/PS1 mice
A first glimpse into butchery practices in Pre-Pottery Neolithic Cyprus: Evidence on sheep and goat remains from six sites
Butchery marks have not been considered very much in Cypriot zooarchaeology. This study aims to contribute towards filling this gap through a study of butchery marks on six Pre-Pottery Neolithic sheep and goat (caprine) assemblages in Cyprus. Taking into account the preservation condition of each assemblage, the analyses of the frequency and types of butchery marks, indicated some interesting trends. Most of these corroborate other lines of archaeological evidence indicating diversity in economic and social practices, which appear to vary both chronologically and geographically. Increased occurrence of butchery marks and differentiation in their types are compatible with a scenario of economic intensification in the 7th millennium cal. BC, at least at some sites. Moreover, the detection of butchery marks on caprine carcasses deposited in the vicinity of human remains in well 133 at Mylouthkia supports the interpretation of a deliberate deposition as part of Pre-Pottery Neolithic funerary practices in Cyprus
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