22 research outputs found
The RedGOLD cluster detection algorithm and its cluster candidate catalogue for the CFHT-LS W1
We present RedGOLD (Red-sequence Galaxy Overdensity cLuster Detector), a new optical/NIR galaxy cluster detection algorithm, and apply it to the CFHT-LS W1 field. RedGOLD searches for red-sequence galaxy overdensities while minimizing contamination from dusty star-forming galaxies. It imposes an NavarroâFrenkâWhite profile and calculates cluster detection significance and richness. We optimize these latter two parameters using both simulations and X-ray-detected cluster catalogues, and obtain a catalogue âŒ80âperâcent pure up to z ⌠1, and âŒ100âperâcent (âŒ70âperâcent) complete at z †0.6 (z âČ 1) for galaxy clusters with M âł 10^(14)âM_â at the CFHT-LS Wide depth. In the CFHT-LS W1, we detect 11 cluster candidates per deg^2 out to z ⌠1.1. When we optimize both completeness and purity, RedGOLD obtains a cluster catalogue with higher completeness and purity than other public catalogues, obtained using CFHT-LS W1 observations, for M âł 10^(14)âM_â. We use X-ray-detected cluster samples to extend the study of the X-ray temperatureâoptical richness relation to a lower mass threshold, and find a mass scatter at fixed richness of Ï_(lnM|λ) = 0.39 ± 0.07 and Ï_(lnM|λ) = 0.30 ± 0.13 for the Gozaliasl et al. and Mehrtens et al. samples. When considering similar mass ranges as previous work, we recover a smaller scatter in mass at fixed richness. We recover 93âperâcent of the redMaPPer detections, and find that its richness estimates is on average âŒ40â50âperâcent larger than ours at z > 0.3. RedGOLD recovers X-ray cluster spectroscopic redshifts at better than 5âperâcent up to z ⌠1, and the centres within a few tens of arcseconds
Environmental dependence of bulge-dominated galaxy sizes in hierarchical models of galaxy formation. Comparison with the local Universe
We compare state-of-the-art semi-analytic models of galaxy formation as well
as advanced sub-halo abundance matching models with a large sample of
early-type galaxies from SDSS at z < 0.3. We focus our attention on the
dependence of median sizes of central galaxies on host halo mass. The data do
not show any difference in the structural properties of early-type galaxies
with environment, at fixed stellar mass. All hierarchical models considered in
this work instead tend to predict a moderate to strong environmental
dependence, with the median size increasing by a factor of about 1.5-3 when
moving from low to high mass host haloes. At face value the discrepancy with
the data is highly significant, especially at the cluster scale, for haloes
above log Mhalo > 14. The convolution with (correlated) observational errors
reduces some of the tension. Despite the observational uncertainties, the data
tend to disfavour hierarchical models characterized by a relevant contribution
of disc instabilities to the formation of spheroids, strong gas dissipation in
(major) mergers, short dynamical friction timescales, and very short quenching
timescales in infalling satellites. We also discuss a variety of additional
related issues, such as the slope and scatter in the local size-stellar mass
relation, the fraction of gas in local early-type galaxies, and the general
predictions on satellite galaxies.Comment: 27 pages, 14 figures, 2 tables. MNRAS, in pres
Avoiding Progenitor Bias: The Structural and Mass Evolution of Brightest Group and Cluster Galaxies in Hierarchical Models since zâŸ1
The mass and structural evolution of massive galaxies is one of the hottest topics in galaxy formation. This is because it may reveal invaluable insights into the still debated evolutionary processes governing the growth and assembly of spheroids. However, direct comparison between models and observations is usually prevented by the so-called progenitor bias, i.e., new galaxies entering the observational selection at later epochs, thus eluding a precise study of how pre-existing galaxies actually evolve in size. To limit this effect, we here gather data on high-redshift brightest group and cluster galaxies, evolve their (mean) host halo masses down to z = 0 along their main progenitors, and assign as their "descendants" local Sloan Digital Sky Survey central galaxies matched in host halo mass. At face value, the comparison between high redshift and local data suggests a noticeable increase in stellar mass of a factor of âł 2 since z ~ 1, and of âł 2.5 in mean effective radius. We then compare the inferred stellar mass and size growth with those predicted by hierarchical models for central galaxies, selected at high redshifts to closely match the halo and stellar mass bins as in the data. Only hierarchical models characterized by very limited satellite stellar stripping and parabolic orbits are capable of broadly reproducing the stellar mass and size increase of a factor of ~2-4 observed in cluster galaxies since z ~ 1. The predicted, average (major) merger rate since z ~ 1 is in good agreement with the latest observational estimates
Cabozantinib in progressive medullary thyroid cancer
Purpose
Cabozantinib, a tyrosine kinase inhibitor (TKI) of hepatocyte growth factor receptor (MET), vascular endothelial growth factor receptor 2, and rearranged during transfection (RET), demonstrated clinical activity in patients with medullary thyroid cancer (MTC) in phase I.
Patients and Methods
We conducted a double-blind, phase III trial comparing cabozantinib with placebo in 330 patients with documented radiographic progression of metastatic MTC. Patients were randomly assigned (2:1) to cabozantinib (140 mg per day) or placebo. The primary end point was progression-free survival (PFS). Additional outcome measures included tumor response rate, overall survival, and safety.
Results
The estimated median PFS was 11.2 months for cabozantinib versus 4.0 months for placebo (hazard ratio, 0.28; 95% CI, 0.19 to 0.40; P < .001). Prolonged PFS with cabozantinib was observed across all subgroups including by age, prior TKI treatment, and RET mutation status (hereditary or sporadic). Response rate was 28% for cabozantinib and 0% for placebo; responses were seen regardless of RET mutation status. Kaplan-Meier estimates of patients alive and progression-free at 1 year are 47.3% for cabozantinib and 7.2% for placebo. Common cabozantinib-associated adverse events included diarrhea, palmar-plantar erythrodysesthesia, decreased weight and appetite, nausea, and fatigue and resulted in dose reductions in 79% and holds in 65% of patients. Adverse events led to treatment discontinuation in 16% of cabozantinib-treated patients and in 8% of placebo-treated patients.
Conclusion
Cabozantinib (140 mg per day) achieved a statistically significant improvement of PFS in patients with progressive metastatic MTC and represents an important new treatment option for patients with this rare disease. This dose of cabozantinib was associated with significant but manageable toxicity
The Next Generation Virgo Cluster Survey. XX. RedGOLD Background Galaxy Cluster Detections
We build a background cluster candidate catalog from the Next Generation Virgo Cluster Survey (NGVS) using our detection algorithm RedGOLD. The NGVS covers 104 deg^2 of the Virgo cluster in the u*, g, r, i, z-bandpasses to a depth of g ~ 25.7 mag (5Ï). Part of the survey was not covered or has shallow observations in the r band. We build two cluster catalogs: one using all bandpasses, for the fields with deep r-band observations (~20 deg^2), and the other using four bandpasses (u*, g, i, z) for the entire NGVS area. Based on our previous CanadaâFranceâHawaii Telescope Legacy Survey W1 studies, we estimate that both of our catalogs are ~100% (~70%) complete and ~80% pure, at z †0.6 (z âŸ1), for galaxy clusters with masses of M âł 10^(14) Mâ. We show that when using four bandpasses, though the photometric redshift accuracy is lower, RedGOLD detects massive galaxy clusters up to z ~ 1 with completeness and purity similar to the five-band case. This is achieved when taking into account the bias in the richness estimation, which is ~40% lower at 0.5 †z 1.4 Ă 10^(14) Mâ and 0.08 < z < 0.5. Because of our different cluster richness limits and the NGVS depth, our catalogs reach lower masses than the published redMaPPer cluster catalog over the area, and we recover ~90%â100% of its detections
The Next Generation Virgo Cluster Survey - Infrared (NGVS-IR): I. A new Near-UV/Optical/Near-IR Globular Cluster selection tool
The NGVS-IR project (Next Generation Virgo Survey - Infrared) is a contiguous
near-infrared imaging survey of the Virgo cluster of galaxies. It complements
the optical wide-field survey of Virgo (NGVS). The current state of NGVS-IR
consists of Ks-band imaging of 4 deg^2 centered on M87, and J and Ks-band
imaging of 16 deg^2 covering the region between M49 and M87. In this paper, we
present the observations of the central 4 deg^2 centered on Virgo's core
region. The data were acquired with WIRCam on the Canada-France-Hawaii
Telescope and the total integration time was 41 hours distributed in 34
contiguous tiles. A survey-specific strategy was designed to account for
extended galaxies while still measuring accurate sky brightness within the
survey area. The average 5\sigma limiting magnitude is Ks=24.4 AB mag and the
50% completeness limit is Ks=23.75 AB mag for point source detections, when
using only images with better than 0.7" seeing (median seeing 0.54"). Star
clusters are marginally resolved in these image stacks, and Virgo galaxies with
\mu_Ks=24.4 AB mag arcsec^-2 are detected. Combining the Ks data with optical
and ultraviolet data, we build the uiK color-color diagram which allows a very
clean color-based selection of globular clusters in Virgo. This diagnostic plot
will provide reliable globular cluster candidates for spectroscopic follow-up
campaigns needed to continue the exploration of Virgo's photometric and
kinematic sub-structures, and will help the design of future searches for
globular clusters in extragalactic systems. Equipped with this powerful new
tool, future NGVS-IR investigations based on the uiK diagram will address the
mapping and analysis of extended structures and compact stellar systems in and
around Virgo galaxies.Comment: 23 pages, 18 figures. Accepted for publication in ApJ
A Phase II Trial of the Multitargeted Tyrosine Kinase Inhibitor Lenvatinib (E7080) in Advanced Medullary Thyroid Cancer
Positive results of phase I studies evaluating lenvatinib in solid tumors, including thyroid cancer, prompted a phase II trial in advanced medullary thyroid carcinoma (MTC)
A phase 2 trial of lenvatinib (E7080) in advanced, progressive, radioiodine-refractory, differentiated thyroid cancer: A clinical outcomes and biomarker assessment
Lenvatinib is an oral, multitargeted tyrosine kinase inhibitor of the vascular endothelial growth factor receptors 1 through 3 (VEGFR1-VEGFR3), fibroblast growth factor receptors 1 through 4 (FGFR1-FGFR4), platelet-derived growth factor receptor α (PDGFRα), ret proto-oncogene (RET), and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) signaling networks implicated in tumor angiogenesis. Positive phase 1 results in solid tumors prompted a phase 2 trial in patients with advanced, radioiodine-refractory, differentiated thyroid cancer (RR-DTC)
Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study
: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (pâ=â0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (pâ=â0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (pâ=â0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (pâ=â0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (pâ=â0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (pâ=â0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (pâ=â0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (pâ<â0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (pâ=â0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (pâ=â0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)
Risultati dello studio di fase III, randomizzato, controllato, in doppio cieco, Sorafenib vs Placebo nel trattamento del carcinoma differenziato della tiroide (CDT) localmente avanzato o metastatico, refrattario al 131I, in progressione.
Il sorafenib ha presentato risultati clinici promettenti in studi di fase II su pazienti (pz) affetti da CDT refrattario al 131I.
Scopo dello studio: confrontare lâefficacia e la tollerabilitĂ del sorafenib e del placebo in pz con CDT in progressione e refrattario al 131I (Studio di fase III).
Metodi: Sono stati randomizzati 1:1 (sorafenib 800 mg/die vs placebo) 417 pz con CDT localmente avanzato o metastatico, refrattario alla terapia con 131I, con documentata progressione di malattia nei 14 mesi precedenti. L'obiettivo primario era la sopravvivenza libera da progressione di malattia (PFS) valutata ogni 8 settimane. Gli obiettivi secondari comprendevano la sopravvivenza globale (OS), il tasso di risposta (RR) [remissione completa (CR)+risposta parziale (PR)] e la tollerabilitĂ del farmaco.
Risultati: sono stati randomizzati 207 pz nel braccio del sorafenib e 210 nel braccio del placebo, con istotipo papillare nel 57% dei casi, follicolare nel 25% e scarsamente differenziato nel 10% dei casi.Lâobiettivo primario di migliorare la PFS media Ăš stato raggiunto: sorafenib 10,8 mesi vs placebo 5,8 mesi (p 6 mesi Ăš stata del 42% e del 33% , rispettivamente. I piĂč comuni effetti collaterali osservati con il sorafenib sono stati: la sindrome mano-piede (76,3%), la diarrea (68,6%), lâalopecia (67,1%), lâesantema (50,2%), lâastenia (49,8%), il dimagramento (46,9%) e lâipertensione (40,6%).
Conclusioni: Il sorafenib rispetto al placebo ha migliorato in maniera significativa la PFS nei pz affetti da CDT in progressione e refrattario al 131I