1,355 research outputs found
Weak Lensing Mass Reconstruction of the Galaxy Cluster Abell 209
Weak lensing applied to deep optical images of clusters of galaxies provides
a powerful tool to reconstruct the distribution of the gravitating mass
associated to these structures. We use the shear signal extracted by an
analysis of deep exposures of a region centered around the galaxy cluster Abell
209, at redshift z=0.2, to derive both a map of the projected mass distribution
and an estimate of the total mass within a characteristic radius. We use a
series of deep archival R-band images from CFHT-12k, covering an area of 0.3
deg^2. We determine the shear of background galaxy images using a new
implementation of the modified Kaiser-Squires-Broadhurst pipeline for shear
determination, which we has been tested against the ``Shear TEsting Program 1
and 2'' simulations. We use mass aperture statistics to produce maps of the 2
dimensional density distribution, and parametric fits using both
Navarro-Frenk-White (NFW) and singular-isothermal-sphere profiles to constrain
the total mass. The projected mass distribution shows a pronounced asymmetry,
with an elongated structure extending from the SE to the NW. This is in general
agreement with the optical distribution previously found by other authors. A
similar elongation was previously detected in the X-ray emission map, and in
the distribution of galaxy colours. The circular NFW mass profile fit gives a
total mass of M_{200} = 7.7^{+4.3}_{-2.7} 10^{14} solar masses inside the
virial radius r_{200} = 1.8\pm 0.3 Mpc. The weak lensing profile reinforces the
evidence for an elongated structure of Abell 209, as previously suggested by
studies of the galaxy distribution and velocities.Comment: accepted by A&A, 15 pages, 11 figure
Current exposure of Italian women of reproductive age to PFOS and PFOA: a human biomonitoring study
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) concentrations were determined in serum samples collected in 2011-2012 from 549 nulliparous Italian women of reproductive age who resided in six different Italian Regions. Assessment of exposure to perfluorinated compounds was part of a large human biomonitoring study (Project Life Plus "Womenbiopop") that aimed at examining the exposure of women of reproductive age to priority organic pollutants. The median concentrations of PFOS and PFOA were 2.43, and 1.55ngg-1, respectively. Significant differences in the concentrations of both compounds were observed among the six Regions. Women from central Italy had the highest levels of both compounds, followed by women from northern Italy, and southern Italy. No differences in the PFOS concentrations were found between women from urban/industrial areas and women from rural areas, whereas the levels of PFOA were significantly higher in women residing in urban/industrial areas than in women residing in rural areas. Taken together, the observed concentrations confirm that the overall exposure of the Italian population is among the lowest observed in industrialized countries. A downward temporal trend in exposure was observed for both compounds when comparing the results from the present study with those assessed in a study conducted in 2008
Selected amino acid changes in HIV-1 subtype-C gp41 are associated with specific gp120(V3) signatures in the regulation of co-receptor usage
The majority of studies have characterized the tropism of HIV-1 subtype-B isolates, but little is known about the determinants of tropism in other subtypes. So, the goal of the present study was to genetically characterize the envelope of viral proteins in terms of co-receptor usage by analyzing 356 full-length env sequences derived from HIV-1 subtype-C infected individuals. The co-receptor usage of V3 sequences was inferred by using the Geno2Pheno and PSSM algorithms, and also analyzed to the "11/25 rule". All reported env sequences were also analyzed with regard to N-linked glycosylation sites, net charge and hydrophilicity, as well as the binomial correlation phi coefficient to assess covariation among gp120(V3) and gp41 signatures and the average linkage hierarchical agglomerative clustering were also performed. Among env sequences present in Los Alamos Database, 255 and 101 sequences predicted as CCR5 and CXCR4 were selected, respectively. The classical V3 signatures at positions 11 and 25, and other specific V3 and gp41 amino acid changes were found statistically associated with different co-receptor usage. Furthermore, several statistically significant associations between V3 and gp41 signatures were also observed. The dendrogram topology showed a cluster associated with CCR5-usage composed by five gp41 mutated positions, A22V, R133M, E136G, N140L, and N166Q that clustered with T2V(V3) and G24T(V3) (bootstrap=1). Conversely, a heterogeneous cluster with CXCR4-usage, involving S11GR(V3), 13-14insIG/LG(V3), P16RQ(V3), Q18KR(V3), F20ILV(V3), D25KRQ(V3), Q32KR(V3) along with A30T(gp41), S107N(gp41), D148E(gp41), A189S(gp41) was identified (bootstrap=0.86). Our results show that as observed for HIV-1 subtype-B, also in subtype-C specific and different gp41 and gp120V3 amino acid changes are associated individually or together with CXCR4 and/or CCR5 usage. These findings strengthen previous observations that determinants of tropism may also reside in the gp41 protein
Cardiovascular events and treatment of children with high risk medulloblastoma
Background: Children with high-risk medulloblastoma are treated with chemotherapeutic protocols which may affect heart function. We aimed to assesscardiovascular events (CVE) in children with medulloblastoma/primitive neuroectodermal tumors (PNET). Methods: We retrospectively collected data from a case series of 22 children with high-risk medulloblastoma/PNET admitted to the Santobono-Pausilipon Hospital, Naples, Italy from 2008 to 2016. All patients received the Milan HART protocol for high-risk brain malignancies as first line treatment (induction phase), followed by a consolidation phase with Thiotepa and hematopoietic stem cells transplantation, except for 1 patient who received the Milan HART as second line therapy. Four patients also received second line treatment, while 4 patients also received maintenance therapy. Patients underwent cardiac examination, including ECG, echocardiography and serum biomarkers, before antineoplastic treatment initiation and then when clinically needed. Six patients developed CVE (CVE group); 16 patients had no CVE (NO-CVE group). Findings: In the CVE group, 3 patients presented acute CVE during chemotherapy (2 patients with left ventricular (LV) dysfunction, 1 patient with arterial hypertension), while 3 patients presented chronic CVE after chemotherapy completion (2 patients with LV dysfunction, 1 patient with ectopic atrial tachycardia). After a 51 months median follow-up, 9 patients died: 4 from the CVE group (in 2 cases heart failure-related deaths) and 5 from the NO-CVE group (progression of disease). Interpretation: A relevant percentage of children treated for medulloblastoma/PNET develops CVE. Heart failure potentially due to chemotherapy may represent a cause of death. Hence, in these patients, strict cardiac surveillance is essential. Funding: No funding was associated with this study
Transcriptional Regulation of VEGF-A by the Unfolded Protein Response Pathway
BACKGROUND: Angiogenesis is crucial to many physiological and pathological processes including development and cancer cell survival. Vascular endothelial growth factor-A (VEGFA) is the predominant mediator of angiogenesis in the VEGF family. During development, adverse environmental conditions like nutrient deprivation, hypoxia and increased protein secretion occur. IRE1alpha, PERK, and ATF6alpha, master regulators of the unfolded protein response (UPR), are activated under these conditions and are proposed to have a role in mediating angiogenesis.
PRINCIPAL FINDINGS: Here we show that IRE1alpha, PERK, and ATF6alpha powerfully regulate VEGFA mRNA expression under various stress conditions. In Ire1alpha(-/-) and Perk(-/-) mouse embryonic fibroblasts and ATF6alpha-knockdown HepG2 cells, induction of VEGFA mRNA by endoplasmic reticulum stress is attenuated as compared to control cells. Embryonic lethality of Ire1alpha-/- mice is due to the lack of VEGFA induction in labyrinthine trophoblast cells of the developing placenta. Rescue of IRE1alpha and PERK in Ire1alpha(-/-) and Perk(-/-) cells respectively, prevents VEGFA mRNA attenuation. We further report that the induction of VEGFA by IRE1alpha, PERK and ATF6 involves activation of transcription factors, spliced-XBP-1, ATF4 and cleaved ATF6 respectively.
CONCLUSIONS/SIGNIFICANCE: Our results reveal that the IRE1alpha-XBP-1, PERK-ATF4, and ATF6alpha pathways constitute novel upstream regulatory pathways of angiogenesis by modulating VEGF transcription. Activation of these pathways helps the rapidly growing cells to obtain sufficient nutrients and growth factors for their survival under the prevailing hostile environmental conditions. These results establish an important role of the UPR in angiogenesis
Service Orientation and the Smart Grid state and trends
The energy market is undergoing major changes, the most notable of which is the transition from a hierarchical closed system toward a more open one highly based on a âsmartâ information-rich infrastructure. This transition calls for new information and communication technologies infrastructures and standards to support it. In this paper, we review the current state of affairs and the actual technologies with respect to such transition. Additionally, we highlight the contact points between the needs of the future grid and the advantages brought by service-oriented architectures.
CLASH-VLT: Insights on the mass substructures in the Frontier Fields Cluster MACS J0416.1-2403 through accurate strong lens modeling
We present a detailed mass reconstruction and a novel study on the
substructure properties in the core of the CLASH and Frontier Fields galaxy
cluster MACS J0416.1-2403. We show and employ our extensive spectroscopic data
set taken with the VIMOS instrument as part of our CLASH-VLT program, to
confirm spectroscopically 10 strong lensing systems and to select a sample of
175 plausible cluster members to a limiting stellar mass of log(M_*/M_Sun) ~
8.6. We reproduce the measured positions of 30 multiple images with a
remarkable median offset of only 0.3" by means of a comprehensive strong
lensing model comprised of 2 cluster dark-matter halos, represented by cored
elliptical pseudo-isothermal mass distributions, and the cluster member
components. The latter have total mass-to-light ratios increasing with the
galaxy HST/WFC3 near-IR (F160W) luminosities. The measurement of the total
enclosed mass within the Einstein radius is accurate to ~5%, including
systematic uncertainties. We emphasize that the use of multiple-image systems
with spectroscopic redshifts and knowledge of cluster membership based on
extensive spectroscopic information is key to constructing robust
high-resolution mass maps. We also produce magnification maps over the central
area that is covered with HST observations. We investigate the galaxy
contribution, both in terms of total and stellar mass, to the total mass budget
of the cluster. When compared with the outcomes of cosmological -body
simulations, our results point to a lack of massive subhalos in the inner
regions of simulated clusters with total masses similar to that of MACS
J0416.1-2403. Our findings of the location and shape of the cluster dark-matter
halo density profiles and on the cluster substructures provide intriguing tests
of the assumed collisionless, cold nature of dark matter and of the role played
by baryons in the process of structure formation.Comment: 26 pages, 22 figures, 7 tables; accepted for publication in the
Astrophysical Journal. A high-resolution version is available at
https://sites.google.com/site/vltclashpublic/publications/Grillo_etal_2014.pd
CLASH-VLT: The stellar mass function and stellar mass density profile of the z=0.44 cluster of galaxies MACS J1206.2-0847
Context. The study of the galaxy stellar mass function (SMF) in relation to
the galaxy environment and the stellar mass density profile, rho(r), is a
powerful tool to constrain models of galaxy evolution. Aims. We determine the
SMF of the z=0.44 cluster of galaxies MACS J1206.2-0847 separately for passive
and star-forming (SF) galaxies, in different regions of the cluster, from the
center out to approximately 2 virial radii. We also determine rho(r) to compare
it to the number density and total mass density profiles. Methods. We use the
dataset from the CLASH-VLT survey. Stellar masses are obtained by SED fitting
on 5-band photometric data obtained at the Subaru telescope. We identify 1363
cluster members down to a stellar mass of 10^9.5 Msolar. Results. The whole
cluster SMF is well fitted by a double Schechter function. The SMFs of cluster
SF and passive galaxies are statistically different. The SMF of the SF cluster
galaxies does not depend on the environment. The SMF of the passive population
has a significantly smaller slope (in absolute value) in the innermost (<0.50
Mpc), highest density cluster region, than in more external, lower density
regions. The number ratio of giant/subgiant galaxies is maximum in this
innermost region and minimum in the adjacent region, but then gently increases
again toward the cluster outskirts. This is also reflected in a decreasing
radial trend of the average stellar mass per cluster galaxy. On the other hand,
the stellar mass fraction, i.e., the ratio of stellar to total cluster mass,
does not show any significant radial trend. Conclusions. Our results appear
consistent with a scenario in which SF galaxies evolve into passive galaxies
due to density-dependent environmental processes, and eventually get destroyed
very near the cluster center to become part of a diffuse intracluster medium.Comment: A&A accepted, 15 pages, 13 figure
CLASH-VLT: The mass, velocity-anisotropy, and pseudo-phase-space density profiles of the z=0.44 galaxy cluster MACS 1206.2-0847
We use an unprecedented data-set of about 600 redshifts for cluster members,
obtained as part of a VLT/VIMOS large programme, to constrain the mass profile
of the z=0.44 cluster MACS J1206.2-0847 over the radial range 0-5 Mpc (0-2.5
virial radii) using the MAMPOSSt and Caustic methods. We then add external
constraints from our previous gravitational lensing analysis. We invert the
Jeans equation to obtain the velocity-anisotropy profiles of cluster members.
With the mass-density and velocity-anisotropy profiles we then obtain the first
determination of a cluster pseudo-phase-space density profile. The kinematics
and lensing determinations of the cluster mass profile are in excellent
agreement. This is very well fitted by a NFW model with mass M200=(1.4 +- 0.2)
10^15 Msun and concentration c200=6 +- 1, only slightly higher than theoretical
expectations. Other mass profile models also provide acceptable fits to our
data, of (slightly) lower (Burkert, Hernquist, and Softened Isothermal Sphere)
or comparable (Einasto) quality than NFW. The velocity anisotropy profiles of
the passive and star-forming cluster members are similar, close to isotropic
near the center and increasingly radial outside. Passive cluster members follow
extremely well the theoretical expectations for the pseudo-phase-space density
profile and the relation between the slope of the mass-density profile and the
velocity anisotropy. Star-forming cluster members show marginal deviations from
theoretical expectations. This is the most accurate determination of a cluster
mass profile out to a radius of 5 Mpc, and the only determination of the
velocity-anisotropy and pseudo-phase-space density profiles of both passive and
star-forming galaxies for an individual cluster [abridged]Comment: A&A in press; 22 pages, 19 figure
CLASH: Extending galaxy strong lensing to small physical scales with distant sources highly-magnified by galaxy cluster members
We present a strong lensing system in which a double source is imaged 5 times
by 2 early-type galaxies. We take advantage in this target of the multi-band
photometry obtained as part of the CLASH program, complemented by the
spectroscopic data of the VLT/VIMOS and FORS2 follow-up campaign. We use a
photometric redshift of 3.7 for the source and confirm spectroscopically the
membership of the 2 lenses to the galaxy cluster MACS J1206.2-0847 at redshift
0.44. We exploit the excellent angular resolution of the HST/ACS images to
model the 2 lenses in terms of singular isothermal sphere profiles and derive
robust effective velocity dispersions of (97 +/- 3) and (240 +/- 6) km/s. The
total mass distribution of the cluster is also well characterized by using only
the local information contained in this lensing system, that is located at a
projected distance of more than 300 kpc from the cluster luminosity center.
According to our best-fitting lensing and composite stellar population models,
the source is magnified by a total factor of 50 and has a luminous mass of
about (1.0 +/- 0.5) x 10^{9} M_{Sun}. By combining the total and luminous mass
estimates of the 2 lenses, we measure luminous over total mass fractions
projected within the effective radii of 0.51 +/- 0.21 and 0.80 +/- 0.32. With
these lenses we can extend the analysis of the mass properties of lens
early-type galaxies by factors that are about 2 and 3 times smaller than
previously done with regard to, respectively, velocity dispersion and luminous
mass. The comparison of the total and luminous quantities of our lenses with
those of astrophysical objects with different physical scales reveals the
potential of studies of this kind for investigating the internal structure of
galaxies. These studies, made possible thanks to the CLASH survey, will allow
us to go beyond the current limits posed by the available lens samples in the
field.Comment: 20 pages, 10 figures, accepted for publication in the Astrophysical
Journa
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