Distinguishing Dark Matter Cusps from Cores using Globular Clusters

Globular Clusters (GCs) provide valuable insight into the properties of their host galaxies' dark matter halos. Using N-body simulations incorporating semianalytic dynamical friction and GC-GC merger prescriptions, we study the evolution of GC radial distributions and mass functions in cuspy and cored dark matter halos. Modeling the dynamics of the GC-rich system in the dwarf galaxy UGC7369, we find that friction-induced inspiral and subsequent mergers of massive GCs can naturally and robustly explain the mass segregation of the GCs and the existence of a nuclear star cluster (NSC). However, the multiple mergers required to form the NSC only take place when the dark matter halo is cuspy. In a cored halo, stalling of the dynamical friction within the core halts the inspiral of the GCs, and so the GC merger rate falls significantly, precluding the formation of an NSC. We therefore argue that the presence of an NSC requires a cusp in UGC7369. More generally, we propose that the presence of an NSC and the corresponding alteration of the GC mass function due to mergers may be used as an indicator of a cuspy halo for galaxies in which we expect NSC formation to be merger-dominated. These observables represent a simple, powerful complement to other inner halo density profile constraint techniques, and should allow for straightforward extension to larger samples.Comment: 19 pages, 11 figures. Main results in figures 7 and 8. Submitted to ApJ, comments are welcome

Risk Assessment and Health, Safety, and Environmental Management of Carbon Nanomaterials

The management of health, safety, and environmental (HSE) aspects during production, manipulation, storage, incorporation, and disposal of carbon nanomaterials is the key factor for the development of a safe-by-design work based on nanotechnology. The almost endless possibility of functionalization, chemical interaction, and addition of nanomaterials into new products implies a new management approach of HSE. Low amount of reliable toxicity and ecotoxicity data of nanomaterials and nanomaterial composites is available. As complete exposure/release assessments are a challenging task, recommendation for control measurements is still based on the precautionary point of view. There is an incomplete understanding of environmental fate- and time-related exposure, and of consumer- and worker-related risks and hazards. Control banding and risk evaluation matrix tools can be used to mitigate labor and environment impacts of carbon nanomaterials. This chapter presents new tools and methodologies for exposure assessment and risk evaluation of hazards used on HSE management system of carbon nanomaterials

Towards a time-reversal mirror for quantum systems

The reversion of the time evolution of a quantum state can be achieved by changing the sign of the Hamiltonian as in the polarization echo experiment in NMR. In this work we describe an alternative mechanism inspired by the acoustic time reversal mirror. By solving the inverse time problem in a discrete space we develop a new procedure, the perfect inverse filter. It achieves the exact time reversion in a given region by reinjecting a prescribed wave function at its periphery.Comment: 6 pages, 4 figures. Introduction modified, references added, one figure added to improve the discussio

ELVES III: Environmental Quenching by Milky Way-Mass Hosts

Isolated dwarf galaxies usually exhibit robust star formation but satellite dwarf galaxies are often devoid of young stars, even in Milky Way-mass groups. Dwarf galaxies thus offer an important laboratory of the environmental processes that cease star formation. We explore the balance of quiescent and star-forming galaxies (quenched fractions) for a sample of ~400 satellite galaxies around 30 Local Volume hosts from the Exploration of Local VolumE Satellites (ELVES) Survey. We present quenched fractions as a function of satellite stellar mass, projected radius, and host halo mass, to conclude that overall, the quenched fractions are similar to the Milky Way, dropping below 50% at satellite M* ~ 10^8 M_sun. We may see hints that quenching is less efficient at larger radius. Through comparison with the semi-analytic modeling code satgen, we are also able to infer average quenching times as a function of satellite mass in host halo-mass bins. There is a gradual increase in quenching time with satellite stellar mass rather than the abrupt change from rapid to slow quenching that has been inferred for the Milky Way. We also generally infer longer average quenching times than recent hydrodynamical simulations. Our results are consistent with models that suggest a wide range of quenching times are possible via ram-pressure stripping, depending on the clumpiness of the circumgalactic medium, the orbits of the satellites, and the degree of earlier preprocessing.Comment: 18 pages, 12 figures, replaced post-refereeing, no major change

ELVES IV: The Satellite Stellar-to-Halo Mass Relation Beyond the Milky-Way

Quantifying the connection between galaxies and their host dark matter halos has been key for testing cosmological models on various scales. Below $M_\star \sim 10^9\,M_\odot$, such studies have primarily relied on the satellite galaxy population orbiting the Milky Way. Here we present new constraints on the connection between satellite galaxies and their host dark matter subhalos using the largest sample of satellite galaxies in the Local Volume ($D \lesssim 12\,\mathrm{Mpc}$) to date. We use $250$ confirmed and $71$ candidate dwarf satellites around 27 Milky Way (MW)-like hosts from the Exploration of Local VolumE Satellites (ELVES) Survey and use the semi-analytical SatGen model for predicting the population of dark matter subhalos expected in the same volume. Through a Bayesian model comparison of the observed and the forward-modeled satellite stellar mass functions (SSMF), we infer the satellite stellar-to-halo mass relation. We find that the observed SSMF is best reproduced when subhalos at the low mass end are populated by a relation of the form $M_\star \propto M^\alpha_\mathrm{peak}$, with a moderate slope of $\alpha_\mathrm{const}=2.10 \pm 0.01$ and a low scatter, constant as a function of the peak halo mass, of $\sigma_\mathrm{const}=0.06^{+0.07}_{-0.05}$. A model with a steeper slope ($\alpha_\mathrm{grow}=2.39 \pm 0.06$) and a scatter that grows with decreasing $M_\mathrm{peak}$ is also consistent with the observed SSMF but is not required. Our new model for the satellite-subhalo connection, based on hundreds of Local Volume satellite galaxies, is in line with what was previously derived using only the Milky Way satellites.Comment: Accepted for publication in ApJ. Figure 8 shows the key result -- the Satellite Stellar to Halo Mass relation obtained in this work, in comparison to previous studie

Medical imaging in the diagnosis of schistosomiasis: a review

Schistosomiasis is one of the most important parasitic diseases and it is endemic in tropical and subtropical areas. Clinical and laboratory data are fundamental for the diagnosis of schistosomiasis, but diagnostic imaging techniques such as x-rays, ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) may be helpful in the evaluation of disease severity and complications. In this context, the aim of this review is to explore the actual role of diagnostic imaging in the diagnosis of schistosomiasis, underlining advantages and drawbacks providing information about the utilization of diagnostic imaging techniques in this context. Furthermore, we aim to provide a useful guide regarding imaging features of schistosomiasis for radiology and nuclear medicine physicians of non-endemic countries: in fact, in the last years non-endemic countries have experienced important flows of migrants from endemic areas, therefore it is not uncommon to face cases of this disease in daily practice

Role of combined DWIBS/3D-CE-T1w whole-body MRI in tumor staging: Comparison with PET-CT

Objectives: To assess the diagnostic performance of whole-body magnetic resonance imaging (WB-MRI) by diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) in malignant tumor detection and the potential diagnostic advantages in generating fused DWIBS/3D-contrast enhanced T1w (3D-CE-T1w) images. Methods: 45 cancer patients underwent 18F-FDG PET-CT and WB-MRI for staging purpose. Fused DWIBS/3D-CE T1w images were generated off-line. 3D-CE-T1w, DWIBS images alone and fused with 3D-CE T1w were compared by two readers groups for detection of primary diseases and local/distant metastases. Diagnostic performance between the three WB-MRI data sets was assessed using receiver operating characteristic (ROC) curve analysis. Imaging exams and histopathological results were used as standard of references. Results: Areas under the ROC curves of DWIBS vs. 3D-CE-T1w vs. both sequences in fused fashion were 0.97, 0.978, and 1.00, respectively. The diagnostic performance in tumor detection of fused DWIBS/3DCE- T1w images were statistically superior to DWIBS (p < 0.001) and 3D-CE-T1w (p ≤ 0.002); while the difference between DWIBS and 3D-CE-T1w did not show statistical significance difference. Detection rates of malignancy did not differ between WB-MRI with DWIBS and 18F-FDG PET-CT. Conclusion: WB-MRI with DWIBS is to be considered as alternative tool to conventional whole-body methods for tumor staging and during follow-up in cancer patients