Compact groups of dwarf galaxies in TNG50: late hierarchical assembly and delayed stellar build-up in the low-mass regime

Compact groups of dwarf galaxies (CGDs) have been observed at low redshifts ($z<0.1$) and are direct evidence of hierarchical assembly at low masses. To understand the formation of CGDs and the galaxy assembly in the low-mass regime, we search for analogues of compact (radius $\leq 100$ kpc) groups of dwarfs ($7 \leq \log[M_{\ast}/{\rm M}_\odot] \leq 9.5$) in the IllustrisTNG highest-resolution simulation. Our analysis shows that TNG50-1 can successfully produce CGDs at $z=0$ with realistic total and stellar masses. We also find that the CGD number density decreases towards the present, especially at $z \lesssim 0.26$, reaching $n \approx 10^{-3.5}$ $\rm cMpc^{-3}$ at $z = 0$. This prediction can be tested observationally with upcoming surveys targeting the faint end of the galaxy population and is essential to constrain galaxy evolution models in the dwarf regime. The majority of simulated groups at $z \sim 0$ formed recently ($\lesssim 1.5 \ \rm Gyr$), and CGDs identified at $z \leq 0.5$ commonly take more than 1 Gyr to merge completely, giving origin to low- to intermediate-mass ($8 \leq \log[M_{\ast}/{\rm M}_\odot] \leq 10$) normally star-forming galaxies at $z=0$. We find that halos hosting CGDs at $z = 0$ formed later when compared to halos of similar mass, having lower stellar masses and higher total gas fractions. The simulations suggest that CGDs observed at $z \sim 0$ arise from a late hierarchical assembly in the last $\sim 3$ Gyr, producing rapid growth in total mass relative to stellar mass and creating dwarf groups with median halo masses of $\sim 10^{11.3}$ $\rm M_\odot$ and B-band mass-to-light ratios mostly in the range $10 \lesssim M/L \lesssim 100$, in agreement with previous theoretical and observational studies.Comment: 20 pages, 18 figures, 4 tables, accepted by MNRAS. Updated to reflect minor changes made during the referring process. Nearest neighbour catalogues available at http://www.tng-project.org/floresfreitas2

Onboarding experiences:Evidence-based insights

This report presents the insights resulting from a large-scale study conducted by Tilburg University, in co-creation with Altuïtion. Before starting this project, little was known about onboarding experiences at work. Particularly, it was not known which newcomers’ experiences matter most; how they impact expectations and emotions; and how these eventually result in various work outcomes. Besides, the relevance of organizational context (e.g., consumerbrand, employer brand) was relatively unexplored in predicting such experiences and outcomes. The lack of knowledge on these topics, formed the basis for this large-scale study of newcomers' experiences and the role ofemotions and expectations.Even before deciding to apply for a job within an organization, newcomers are exposed to the reputation and the image of the organization. For example,through the employer brand or consumer brand. This may affect the expectations of newcomers. As soon as a new employees start in their new job, they get exposed to all sorts of events which we expect to influence emotions. In this study, we asked newcomers to describe the most impactful work event of the past week, then asked them what emotions they experienced at that moment and if this moment confirmed their expectations. These experiences ultimately were expected to lead to variouswork outcomes. Obviously, one hopes that the newcomers’ experiences are such that they also result in positive outcomes such as improved work engagement or lower turnover intentions. In this report, we describe the firstresults of our research that reflects input on over 500 impactful work events

The rate-limiting step for alkane dehydrogenation in zeolite H-ZSM-5.

We have carried out a computational study of protolytic cracking, dehydrogenation, and H/D exchange of ethane, propane, and butane using a cluster model of H-ZSM-5. Our previous work has demonstrated that quantum-chemical techniques can give quantitatively accurate activation energies for alkane cracking in zeolites [1]. Experimental kinetic studies have shown that the apparent activation energies for cracking and H/D exchange decrease with n-alkane chain length, while for dehydrogenation the energies increase [2,3]. Our goal is to study the dependence of the activation energy on the alkane chain length in these reactions and to understand why the dehydrogenation reaction behaves so differently

Onboarding experiences:Evidence-based insights

This report presents the insights resulting from a large-scale study conducted by Tilburg University, in co-creation with Altuïtion. Before starting this project, little was known about onboarding experiences at work. Particularly, it was not known which newcomers’ experiences matter most; how they impact expectations and emotions; and how these eventually result in various work outcomes. Besides, the relevance of organizational context (e.g., consumerbrand, employer brand) was relatively unexplored in predicting such experiences and outcomes. The lack of knowledge on these topics, formed the basis for this large-scale study of newcomers' experiences and the role ofemotions and expectations.Even before deciding to apply for a job within an organization, newcomers are exposed to the reputation and the image of the organization. For example,through the employer brand or consumer brand. This may affect the expectations of newcomers. As soon as a new employees start in their new job, they get exposed to all sorts of events which we expect to influence emotions. In this study, we asked newcomers to describe the most impactful work event of the past week, then asked them what emotions they experienced at that moment and if this moment confirmed their expectations. These experiences ultimately were expected to lead to variouswork outcomes. Obviously, one hopes that the newcomers’ experiences are such that they also result in positive outcomes such as improved work engagement or lower turnover intentions. In this report, we describe the firstresults of our research that reflects input on over 500 impactful work events

Human-like collagen protein-coated magnetic nanoparticles with high magnetic hyperthermia performance and improved biocompatibility

Human-like collagen (HLC)-coated monodispersed superparamagnetic Fe(3)O(4) nanoparticles have been successfully prepared to investigate its effect on heat induction property and cell toxicity. After coating of HLC, the sample shows a faster rate of temperature increase under an alternating magnetic field although it has a reduced saturation magnetization. This is most probably a result of the effective heat conduction and good colloid stability due to the high charge of HLC on the surface. In addition, compared with Fe(3)O(4) nanoparticles before coating with HLC, HLC-coated Fe(3)O(4) nanoparticles do not induce notable cytotoxic effect at higher concentration which indicates that HLC-coated Fe(3)O(4) nanoparticles has improved biocompatibility. Our results clearly show that Fe(3)O(4) nanoparticles after coating with HLC not only possess effective heat induction for cancer treatment but also have improved biocompatibility for biomedicine applications

Impairment of germline transmission after blastocyst injection with murine embryonic stem cells cultured with mouse hepatitis virus and mouse minute virus

The aim of this study was to determine the susceptibility of murine embryonic stem (mESCs) to mouse hepatitis virus (MHV-A59) and mouse minute virus (MMVp) and the effect of these viruses on germline transmission (GLT) and the serological status of recipients and pups. When recipients received 10 blastocysts, each injected with 100 TCID50 MHV-A59, three out of five recipients and four out of 14 pups from three litters became seropositive. When blastocysts were injected with 10−5 TCID50 MMVp, all four recipients and 14 pups from four litters remained seronegative. The mESCs replicated MHV-A59 but not MMVp, MHV-A59 being cytolytic for mESCs. Exposure of mESCs to the viruses over four to five passages but not for 6 h affected GLT. Recipients were seropositive for MHV-A59 but not for MMVp when mESCs were cultured with the virus over four or five passages. The data show that GLT is affected by virus-contaminated mESCs

Atomic force microscopy analysis of nanoparticles in non-ideal conditions

Nanoparticles are often measured using atomic force microscopy or other scanning probe microscopy methods. For isolated nanoparticles on flat substrates, this is a relatively easy task. However, in real situations, we often need to analyze nanoparticles on rough substrates or nanoparticles that are not isolated. In this article, we present a simple model for realistic simulations of nanoparticle deposition and we employ this model for modeling nanoparticles on rough substrates. Different modeling conditions (coverage, relaxation after deposition) and convolution with different tip shapes are used to obtain a wide spectrum of virtual AFM nanoparticle images similar to those known from practice. Statistical parameters of nanoparticles are then analyzed using different data processing algorithms in order to show their systematic errors and to estimate uncertainties for atomic force microscopy analysis of nanoparticles under non-ideal conditions. It is shown that the elimination of user influence on the data processing algorithm is a key step for obtaining accurate results while analyzing nanoparticles measured in non-ideal conditions

Recent progress towards development of effective systemic chemotherapy for the treatment of malignant brain tumors

Systemic chemotherapy has been relatively ineffective in the treatment of malignant brain tumors even though systemic chemotherapy drugs are small molecules that can readily extravasate across the porous blood-brain tumor barrier of malignant brain tumor microvasculature. Small molecule systemic chemotherapy drugs maintain peak blood concentrations for only minutes, and therefore, do not accumulate to therapeutic concentrations within individual brain tumor cells. The physiologic upper limit of pore size in the blood-brain tumor barrier of malignant brain tumor microvasculature is approximately 12 nanometers. Spherical nanoparticles ranging between 7 nm and 10 nm in diameter maintain peak blood concentrations for several hours and are sufficiently smaller than the 12 nm physiologic upper limit of pore size in the blood-brain tumor barrier to accumulate to therapeutic concentrations within individual brain tumor cells. Therefore, nanoparticles bearing chemotherapy that are within the 7 to 10 nm size range can be used to deliver therapeutic concentrations of small molecule chemotherapy drugs across the blood-brain tumor barrier into individual brain tumor cells. The initial therapeutic efficacy of the Gd-G5-doxorubicin dendrimer, an imageable nanoparticle bearing chemotherapy within the 7 to 10 nm size range, has been demonstrated in the orthotopic RG-2 rodent malignant glioma model. Herein I discuss this novel strategy to improve the effectiveness of systemic chemotherapy for the treatment of malignant brain tumors and the therapeutic implications thereof