Summary
The occurrence of conducting vascular tissue in the pith (CVTP) of tracheophytes is noteworthy. Medullary bundles, one of the remarkable examples of CVTP, evolved multiple times across ...angiosperms, notably in the Caryophyllales. Yet, information on the occurrence of medullary bundles is fragmented, hampering our understanding of their structure–function relationships, and evolutionary implications.
Using three plastid molecular markers (matK, rbcL, and rps16 intron), a phylogeny is constructed for 561 species of Caryophyllales, and anatomical data are assembled for 856 species across 40 families to investigate the diversity of medullary bundles, their function, evolution, and diversification dynamics. Additionally, correlated evolution between medullary bundles and successive cambia was tested.
Medullary bundles are ancestrally absent in Caryophyllales and evolved in core and noncore families. They are structurally diverse (e.g. number, arrangement, and types of bundles) and functionally active throughout the plant's lifespan, providing increased hydraulic conductivity, especially in herbaceous plants. Acquisition of medullary bundles does not explain diversification rate heterogeneity but is correlated to a higher diversification rate.
Disparate developmental pathways were found leading to rampant convergent evolution of CVTP in Caryophyllales. These findings indicate the diversification of medullary bundles and vascular tissues as another central theme for functional and comparative molecular studies in Caryophyllales.
Stability features of two-stream coaxial plasma jet simulations are investigated using numerical solutions to the spatio-temporal one-dimensional linear stability theory problem. The base states ...obtained from magneto-hydrodynamic simulations consider the flow as a mixture of gases in local thermodynamic equilibrium (LTE) while stability computations are performed assuming both a calorically perfect gas (CPG) model and LTE. Comparisons with solutions considering a simple CPG model show the non-negligible impact of the LTE on the stability attributes of the plasma jet. For all cases studied, a large region of absolute instability is found for the axisymmetric mode, starting at the jet inlet. The streamwise evolution of the absolute growth rate is found to depend both on the baroclinic torque and the displacement of the maximum shear toward low velocity regions of the jet, combining effects described in the literature. The jet is controlled by means of electric power and static pressure at constant mass flow. The former affects mainly the absolute growth rate through changes of the core-to-bypass stream velocity ratio, while the latter influences mostly the absolute frequency. Finally, the full impulse response reveals a competition mechanism between the absolute mixed modes dominating at low group velocities, and convective shear layer modes at higher group velocities, restricted to the first half of the chamber.
We present a convenient, all-in-one framework for the scientific analysis of fully reduced, (integral-field) spectroscopic data. The Galaxy IFU Spectroscopy Tool (GIST) is entirely written in Python ...3 and conducts all the steps from the preparation of input data to the scientific analysis and to the production of publication-quality plots. In its basic set-up, it extracts stellar kinematics, performs an emission-line analysis, and derives stellar population properties from full spectral fitting and via the measurement of absorption line-strength indices by exploiting the well-known pPXF and GandALF routines, where the latter has now been implemented in Python. The pipeline is not specific to any instrument or analysis technique and provides easy means of modification and further development, thanks to its modular code architecture. An elaborate, Python-native parallelisation is implemented and tested on various machines. The software further features a dedicated visualisation routine with a sophisticated graphical user interface. This allows an easy, fully interactive plotting of all measurements, spectra, fits, and residuals, as well as star formation histories and the weight distribution of the models. The pipeline has been successfully applied to both low- and high-redshift data from MUSE, PPAK (CALIFA), and SINFONI, and to simulated data for HARMONI and WEAVE and is currently being used by the TIMER, Fornax3D, and PHANGS collaborations. We demonstrate its capabilities by applying it to MUSE TIMER observations of NGC 1433.
IntroductionStroop test iteration performances and metabolism of tryptophan (TRP) via serotonin (5-HT) and kynurenine (KYN) have both been associated with suicidal behaviors. This study aims to probe ...their possible interactions.ObjectivesWe explored the association of the performances on the Emotion Inhibition Subtask (EIS) of the Brief Assessment of Cognition for Affective Disorder and the plasmatic levels of 5-hydroxytryptophan (5-HTP), 5-HT, KYN, melatonin (MLT) among subjects with Lifetime Suicidal Ideation (LSI) vs non-LSI, and with Lifetime Suicide Attempts (LSA) vs non-LSA.MethodsUsing R studio, we employed: 1) the t-test for parametric data and the Wilcoxon test for non-parametric data; 2) Linear Modeling to probe the associations of EIS performances with MLT, KYN, 5-HTP or 5-HT plasmatic levels.ResultsIn a sample comprising 45 individuals affected by Bipolar Disorder, we found a statistically significant difference for the Color Naming (CN, image 1) and the Neutral words (NW) subtasks among LSA vs non-LSA. In LSI vs non-LSI, only the NW retained significance, but not the CN. A significant association emerged between CN and 5-HTP in LSI but not in non-LSI (image 2). Similarly, in LSA, an association was found between CN and 5-HTP, but not in non-LSA (image 3). No statistically significant difference emerged among groups regarding gender composition, age, pharmacological therapy, Body Mass Index, Hamilton Depression Rating Scale, Young Mania Rating Scale, or Clinical Global Impression scale - Severity.Image:Image 2:Image 3:ConclusionsWe found that the plasmatic levels of the metabolites of TRP via 5-HT were correlated to some EIS performances. These findings may represent a hypothesis-generating platform for further investigations.Disclosure of InterestNone Declared
Nuclear star clusters (NSCs) are the densest stellar systems in the Universe and are found in the centres of all types of galaxies. They are thought to form via mergers of star clusters such as ...ancient globular clusters (GCs) that spiral to the centre as a result of dynamical friction or through in situ star formation directly at the galaxy centre. There is evidence that both paths occur, but the relative contribution of either channel and their correlation with galaxy properties are not yet constrained observationally. Our aim was to derive the dominant NSC formation channel for a sample of 25 nucleated galaxies, mostly in the Fornax galaxy cluster, with stellar masses between
M
gal
∼ 10
8
and 10
10.5
M
⊙
and NSC masses between
M
NSC
∼ 10
5
and 10
8.5
M
⊙
. Using Multi-Unit Spectroscopic Explorer data from the Fornax 3D survey and the ESO archive, we derived star formation histories, mean ages, and metallicities of NSCs, and compared them to the host galaxies. In many low-mass galaxies, the NSCs are significantly more metal poor than their hosts, with properties similar to GCs. In contrast, in the massive galaxies we find diverse star formation histories and cases of ongoing or recent in situ star formation. Massive NSCs (> 10
7
M
⊙
) occupy a different region in the mass–metallicity diagram than lower-mass NSCs and GCs, indicating a different enrichment history. We find a clear transition of the dominant NSC formation channel with both galaxy and NSC mass. We hypothesise that while GC accretion forms the NSCs of the dwarf galaxies, central star formation is responsible for the efficient mass build up in the most massive NSCs in our sample. At intermediate masses both channels can contribute. The transition between these formation channels seems to occur at galaxy masses
M
gal
∼ 10
9
M
⊙
and NSC masses
M
NSC
∼ 10
7
M
⊙
.
The 31 brightest galaxies (mB ≤ 15 mag) inside the virial radius of the Fornax cluster were observed from the centres to the outskirts with the Multi Unit Spectroscopic Explorer on the Very Large ...Telescope. These observations provide detailed high-resolution maps of the line-of-sight kinematics, line strengths of the stars, ionised gas reaching 2–3 Re for 21 early-type galaxies, and 1–2 Re for 10 late-type galaxies. The majority of the galaxies are regular rotators, with eight hosting a kinematically distinct core. Only two galaxies are slow rotators. The mean age, total metallicity, and Mg/Fe abundance ratio in the bright central region inside 0.5 Re and in the galaxy outskirts are presented. Extended emission-line gas is detected in 13 galaxies, most of them are late-type objects with wide-spread star formation. The measured structural properties are analysed in relation to the galaxies’ position in the projected phase space of the cluster. This shows that the Fornax cluster appears to consist of three main groups of galaxies inside the virial radius: the old core; a clump of galaxies, which is aligned with the local large-scale structure and was accreted soon after the formation of the core; and a group of galaxies that fell in more recently.
This study investigates the stability features of spatially spreading heated jets in the viscous regime with real gas effects, using both unsteady two-dimensional axisymmetric simulations and linear ...analyses of the steady state and time-averaged states. At a Reynolds number of $400$, the heated jets are found to undergo a subcritical Hopf bifurcation, marking the start of self-sustained oscillations when decreasing the temperature ratio $S=T_{\infty }/T_{{c}}$, which highly depends on the thermodynamic and transport property assumptions imposed in the simulations. Once the flow enters a limit cycle past the Hopf bifurcation, the linear analyses over the steady base state are unable to capture the oscillation's frequency. Nevertheless, this study confirms that including real gas effects in the stability equations has a strong effect on the growth rate of the global mode once the centreline temperature of the jet reaches that of the dissociation reaction onset, which is $T=2800$ K for air at $p_s=100$ mbar. The linear global analyses over the time-averaged states lead to a satisfying prediction of the oscillation's frequency for the cases studied, and the baroclinic torque obtained from the resulting global mode matches well with that of the simulations.
We studied the effects of cluster environments on galactic structures by using the TNG50 cosmological simulation and observed galaxies in the Fornax cluster. We focused on galaxies with stellar ...masses of 10 8 − 12 M ⊙ at z = 0 that reside in Fornax-like clusters with total masses of M 200c = 10 13.4 − 14.3 M ⊙ . We characterized the stellar structures by decomposing each galaxy into a dynamically cold disk and a hot non-disk component, and studied the evolution of both the stellar and gaseous constituents. In TNG50, we find that the cold (i.e., star-forming) gas is quickly removed when a galaxy falls into a Fornax-mass cluster. About 42%, 73%, and 87% of the galaxies have lost 80% of their star-forming gas at 1, 2, and 4 billion years after infall, respectively, with the remaining gas concentrating in the inner regions of the galaxy. The radius of the star-forming gaseous disk decreases to half its original size at 1, 2, and 4 billion years after infall for 7%, 27%, and 66% of the galaxies, respectively. As a result, star formation (SF) in the extended dynamically cold disk sharply decreases, even though a low level of SF persists at the center for a few additional gigayears. This leads to a tight correlation between the average stellar age in the dynamically cold disk and the infall time of galaxies. Furthermore, the luminosity fraction of the dynamically cold disk in ancient infallers (i.e., with an infall time ≳8 Gyr ago) is only about one-third of that in recent infallers (infall time ≲4 Gyr ago), controlling for galaxy stellar mass. This quantitatively agrees with what is observed in early-type galaxies in the Fornax cluster. Gas removal stops the possible growth of the disk, with gas removed earlier in galaxies that fell in earlier, and hence the cold-disk fraction is correlated with the infall time. The stellar disk can be significantly disrupted by tidal forces after infall, through a long-term process that enhances the difference among cluster galaxies with different infall times.
ABSTRACT
We combine data from ALMA and MUSE to study the resolved (∼300 pc scale) star formation relation (star formation rate, SFR, versus molecular gas surface density) in cluster galaxies. Our ...sample consists of nine Fornax cluster galaxies, including spirals, ellipticals, and dwarfs, covering a stellar mass range of ∼108.8–1011 M⊙. CO(1-0) and extinction corrected Hα were used as tracers for the molecular gas mass and SFR, respectively. We compare our results with Kennicutt and Bigiel et al. Furthermore, we create depletion time maps to reveal small-scale variations in individual galaxies. We explore these further in FCC290, using the ‘uncertainty principle for star formation’ (Kruijssen & Longmore) to estimate molecular cloud lifetimes, which we find to be short (<10 Myr) in this galaxy. Galaxy-averaged depletion times are compared with other parameters such as stellar mass and cluster-centric distance. We find that the star formation relation in the Fornax cluster is close to those from Kennicutt and Bigiel et al., but overlaps mostly with the shortest depletion times predicted by Bigiel et al. This slight decrease in depletion time is mostly driven by dwarf galaxies with disturbed molecular gas reservoirs close to the virial radius. In FCC90, a dwarf galaxy with a molecular gas tail, we find that depletion times are a factor ≳10 higher in its tail than in its stellar body.
PDF
