608 research outputs found
Embedded Clusters in the Large Magellanic Cloud using the VISTA Magellanic Clouds Survey
Krista Romita, Elizabeth Lada and Maria-Rosa Cioni, 'Embedded clusters in the large magellanic cloud using the vista magellanic clouds survey', The Astrophysical Journal, Vol 821(1), published April 11, 2016. The version of record is available online at doi: 10.3847/0004-637X/821/1/51 © 2016. The American Astronomical Society. All rights reserved.We present initial results of the first large scale survey of embedded star clusters in molecular clouds in the Large Magellanic Cloud (LMC) using near-infrared (NIR) imaging from the VISTA Magellanic Clouds Survey (Cioni et al. 2011). We have explored a 1.65 deg sq. area of the LMC, which contains the well-known star-forming region 30 Doradus as well as 14% of the galaxy's CO clouds (Wong et al. 2011), and have identied 67 embedded cluster candidates, 45 of which are newly discovered as clusters. We have determined sizes, luminosities and masses for these embedded clusters, examined the star formation rates (SFRs) of their corresponding molecular clouds, and made a comparison between the LMC and the Milky Way. Our preliminary results indicate that embedded clusters in the LMC are generally larger, more luminous and more massive than those in the local Milky Way. We also find that the surface densities of both embedded clusters and molecular clouds is 3 times higher than in our local environment, the embedded cluster mass surface density is 40 times higher, the SFR is 20 times higher, and the star formation efficiency is 10 times higher. Despite these differences, the SFRs of the LMC molecular clouds are consistent with the SFR scaling law presented in Lada et al. (2012). This consistency indicates that while the conditions of embedded cluster formation may vary between environments, the overall process within molecular clouds may be universalPeer reviewedFinal Published versio
(Dis)unity in the UN Security Council: Voting Patterns in the UN\u27s Peace and Security Organ
The conventional wisdom is that the international system in the Cold War was defined by the struggle between East and West. While this was certainly the case, voting patterns in the UN Security Council present a more nuanced picture. Counterintuitively, France, the United Kingdom and the United States—three of the five permanent members of the Security Council (the Permanent 3 or P3) and members of the NATO alliance—voted apart on Council resolutions far more frequently in the Cold War, when they faced the common threat of the Soviet Union, than in the post-Cold War era. This dissertation observes that they were frequently divided on issues related to colonialism and Israel/Palestine, among other matters. It argues that the voting differences among them largely had to do with the way the Council functioned, as negotiating processes were underdeveloped and assertive Council members from the Non-aligned Movement (NAM) often proposed draft resolutions which made bold political statements but had little chance of being adopted. As the Cold War ended, however, the permanent members—the P3, as well as Russia and China—gained a newfound appreciation for the potential of a Security Council unhindered by significant East-West tensions. They sought to consolidate their control of the Council’s work. In part because of the perception expressed by permanent and elected members alike that a unified Council is a more effective one, voting unanimity has been achieved on nearly 92 percent of adopted resolutions since 1992. The dissertation further maintains that the NAM has lost its unity and political clout in the post-Cold War, with its members (or for that matter, any other group of members in the Council) less likely to propose draft resolutions destined to be vetoed. At the same time, it posits that the elected members (the Elected 10 or E10), in spite of the differing views among them, at times play a constructive role in the Council’s work, including by building bridges among the permanent members when they are divided
Two compact HII regions at the remote outskirts of the Magellanic Clouds
The H II regions LMC N191 and SMC N77 are among the outermost massive
star-forming regions in the Magellanic Clouds. So far, few works have dealt
with these objects despite their interesting characteristics. We aim at
studying various physical properties of these objects regarding their
morphology (in the optical and Spitzer IRAC wavelengths), ionized gas emission,
nebular chemical abundances, exciting sources, stellar content, age, presence
or absence of young stellar objects, etc. This study is based mainly on optical
ESO NTT observations, both imaging and spectroscopy, coupled with other archive
data, notably Spitzer images (IRAC 3.6, 4.5, 5.8, and 8.0 microns) and 2MASS
observations. We show the presence of two compact H II regions, a
low-excitation blob (LEB) named LMC N191A and a high-excitation blob (HEB)
named SMC N77A, and study their properties and those of their exciting massive
stars as far as spectral type and mass are concerned. We also analyze the
environmental stellar populations and determine their evolutionary stages.
Based on Spitzer IRAC data, we characterize the YSO candidates detected in the
direction of these regions. Massive star formation is going on in these young
regions with protostars of mass about 10 and 20 M_sun in the process of
formation.Comment: 14 pages, 8 figures, 6 tables; Accepted for publication in A&A. arXiv
admin note: substantial text overlap with arXiv:1102.125
A multicentric study on prevalence of clinical patterns and clinical phenotypes in adult atopic dermatitis
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Expansion dynamics of Pb-Pb collisions at 40 A GeV/c viewed by negatively charged hadrons
In this paper we present results on transverse mass spectra and Hanbury-Brown
and Twiss correlation functions of negatively charged hadrons, which are
expected to be mostly negative pions, measured in Pb-Pb collisions at 40 A
GeV/c beam momentum. Based on these data, the collision dynamics and the
space-time extent of the system at the thermal freeze-out are studied over a
centrality range corresponding to the most central 53% of the Pb--Pb inelastic
cross section. Comparisons with freeze-out conditions of strange particles and
HBT results from other experiments are discussed.Comment: 29 pages, 18 figure
Urological melanoma: A comprehensive review of a rare subclass of mucosal melanoma with emphasis on differential diagnosis and therapeutic approaches
Melanoma is reported as the 19th most common cancer worldwide, with estimated age-standardized incidence rates of 2.8–3.1 per 100,000. Although the origin is most frequently cutaneous, mucosal melanoma has been described several times in literature, and despite its rarity (only 1% of all melanomas), increasing attention is being paid to this disease form. Within this subgroup, melanomas of the uropoetic apparatus are a rarity among rarities. Indeed, less than 50 cases of primary melanoma originating from the urinary bladder have been described, and even less originating from the kidney, renal pelvis and urethra. In this work, we present a detailed review of the literature related to this proaches. subclass of mucosal melanoma, delve into the biological landscape of this neoplasm and discuss current approaches, future perspectives and potential therapeutic approaches. Keywords: melanoma; mucosal melanoma; urology
Strangeness enhancements at central rapidity in 40 A GeV/c Pb-Pb collisions
Results are presented on neutral kaon, hyperon and antihyperon production in
Pb-Pb and p-Be interactions at 40 GeV/c per nucleon. The enhancement pattern
follows the same hierarchy as seen in the higher energy data - the enhancement
increases with the strangeness content of the hyperons and with the centrality
of collision. The centrality dependence of the Pb-Pb yields and enhancements is
steeper at 40 than at 158 A GeV/c. The energy dependence of strangeness
enhancements at mid-rapidity is discussed.Comment: 15 pages, 10 figures and 3 tables. Presented at International
Conference on Strangeness in Quark Matter (SQM2009), Buzios, Rio de Janeiro,
Brazil, 27 Sept - 2 Oct 2009. Submitted to J.Phys.G: Nucl.Part.Phys, one
reference adde
Formalin-fixed and paraffin-embedded samples for next generation sequencing: Problems and solutions
Over the years, increasing information has been asked of the pathologist: we have moved from a purely morphological diagnosis to biomolecular and genetic studies, which have made it possible to implement the use of molecular targeted therapies, such as anti-epidermal growth factor receptor (EGFR) molecules in EGFR-mutated lung cancer, for example. Today, next generation sequencing (NGS) has changed the approach to neoplasms, to the extent that, in a short time, it has gained a place of absolute importance and diagnostic, prognostic and therapeutic utility. In this scenario, formaldehyde-fixed and paraffin-embedded (FFPE) biological tissue samples are a source of clinical and molecular information. However, problems can arise in the genetic material (DNA and RNA) for use in NGS due to fixation, and work is being devoted to possible strategies to reduce its effects. In this paper, we discuss the applications of FFPE tissue samples in the execution of NGS, we focus on the problems arising with the use of this type of material for nucleic acid extraction and, finally, we consider the most useful strategies to prevent and reduce single nucleotide polymorphisms (SNV) and other fixation artifacts
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
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