Electronic transitions in Rb2+ dimers solvated in helium

We have measured depletion spectra of the heteronuclear (85Rb87Rb+) dimer cation complexed with up to 10 He atoms. Two absorption bands are observed between 920 and 250 nm. The transition into the repulsive 12Σu+ state of HeRb2+ gives rise to a broad feature at 790 nm (12,650 cm−1); it exhibits a blueshift of 98 cm−1 per added He atom. The transition into the bound 12Πu state of HeRb2+ reveals vibrational structure with a band head at ≤ 15,522 cm−1, a harmonic constant of 26 cm−1, and a spin–orbit splitting of ≤ 183 cm−1. The band experiences an average redshift of − 38 cm−1 per added He atom. Ab initio calculations rationalize the shape of the spectra and spectral shifts with respect to the number of helium atoms attached. For a higher number of solvating helium atoms, symmetric solvation on both ends of the Rb2+ ion is predicted.

FAN-C: a feature-rich framework for the analysis and visualisation of chromosome conformation capture data

Chromosome conformation capture data, particularly from high-throughput approaches such as Hi-C, are typically very complex to analyse. Existing analysis tools are often single-purpose, or limited in compatibility to a small number of data formats, frequently making Hi-C analyses tedious and time-consuming. Here, we present FAN-C, an easy-to-use command-line tool and powerful Python API with a broad feature set covering matrix generation, analysis, and visualisation for C-like data (https://github.com/vaquerizaslab/fanc). Due to its compatibility with the most prevalent Hi-C storage formats, FAN-C can be used in combination with a large number of existing analysis tools, thus greatly simplifying Hi-C matrix analysis.

Synthesis and magnetic properties of the extended RE4Pd9Al24 series (RE = Sc, Y, Ce–Nd, Sm, Gd–Lu)

The existing RE4Pd9Al24 series (triclinic, space group P$\overline{1}$) with RE = Gd–Tm has been extended to the rare earth elements Sc, Y, Ce–Nd, Sm, Yb and Lu. The samples were synthesized from the elements via arc-melting followed by annealing. Phase-purity was checked by powder X-ray diffraction experiments, which were also utilized to refine the lattice parameters. The structure can be described as composed of layers with a stacking of [PtAl2] (A) and [RE2Al3] (B) slabs in an ABAAB sequence. As two different structure types (P$\overline{1}$ and R$\overline{3}$m) have been reported for this composition, a group-subgroup scheme using the Bärnighausen formalism has been established in order to link the two. The magnetic properties of the X-ray-pure samples were investigated by susceptibility and magnetization measurements. Gd4Pd9Al24 shows the highest transition temperature to antiferromagnetism of TN = 22.0(1) K, however, a broad feature is observed. This is in line with a low-dimensional ordering caused by the layer-like structure and the flat honeycomb arrangement of the Gd atoms.

Feature Selection in Big Image Datasets

In computer vision, current feature extraction techniques generate high dimensional data. Both convolutional neural networks and traditional approaches like keypoint detectors are used as extractors of high-level features. However, the resulting datasets have grown in the number of features, leading into long training times due to the curse of dimensionality. In this research, some feature selection methods were applied to these image features through big data technologies. Additionally, we analyzed how image resolutions may affect to extracted features and the impact of applying a selection of the most relevant features. Experimental results show that making an important reduction of the extracted features provides classification results similar to those obtained with the full set of features and, in some cases, outperforms the results achieved using broad feature vectors.

MEGARA-IFU detection of extended He ii λ4686 nebular emission in the central region of NGC 1569 and its ionization budget

ABSTRACT We here report the detection of extended He ii λ4686 nebular emission in the central region of NGC 1569 using the integral field spectrograph MEGARA at the 10.4 m Gran Telescopio Canarias. The observations cover a field of view (FoV) of 12.5 arcsec × 11.3 arcsec at a seeing-limited spatial resolution of ∼15 pc and at a spectral resolution of R = 6000 in the wavelength range 4330–5200 Å. The emission extends over a semicircular arc of ∼40 pc width and ∼150 pc diameter around the superstar cluster A (SSC-A). The AV derived using Balmer decrement varies from the Galactic value of 1.6 mag to a maximum of ∼4.5 mag, with a mean value of 2.65 ± 0.60 mag. We infer 124 ± 11 Wolf–Rayet (WR) stars in SSC-A using the He ii λ4686 broad feature and AV = 2.3 mag. The He+ ionizing photon rate from these WR stars is sufficient to explain the luminosity of the He ii nebula. The observationally determined total He+ and H0 ionizing photon rates, their ratio, and the observed number of WR stars in SSC-A are all consistent with the predictions of simple stellar population models at an age of 4.0 ± 0.5 Myr and a mass of (5.5 ± 0.5) × 105 M⊙. Our observations reinforce the absence of WR stars in SSC-B, the second most massive cluster in the FoV. None of the other locations in our FoV where He ii λ4686 emission has been reported from narrow-band imaging observations contain WR stars.

FAN-C: A Feature-rich Framework for the Analysis and Visualisation of C data

Chromosome conformation capture data, particularly from high-throughput approaches such as Hi-C and its derivatives, are typically very complex to analyse. Existing analysis tools are often single-purpose, or limited in compatibility to a small number of data formats, frequently making Hi-C analyses tedious and time-consuming. Here, we present FAN-C, an easy-to-use command-line tool and powerful Python API with a broad feature set covering matrix generation, analysis, and visualisation for C-like data (https://github.com/vaquerizaslab/fanc). Due to its comprehensiveness and compatibility with the most prevalent Hi-C storage formats, FAN-C can be used in combination with a large number of existing analysis tools, thus greatly simplifying Hi-C matrix analysis.

SAPH-ire TFx – A Recommendation-based Machine Learning Model Captures a Broad Feature Landscape Underlying Functional Post-Translational Modifications

ABSTRACTProtein post-translational modifications (PTMs) are a rapidly expanding feature class of significant importance in cell biology. Due to a high burden of experimental proof, the number of functional PTMs in the eukaryotic proteome is currently underestimated. Furthermore, not all PTMs are functionally equivalent. Therefore, computational approaches that can confidently recommend the functional potential of experimental PTMs are essential. To address this challenge, we developed SAPH-ire TFx (https://saphire.biosci.gatech.edu/): a multi-feature neural network model and web resource optimized for recommending experimental PTMs with high potential for biological impact. The model is rigorously benchmarked against independent datasets and alternative models, exhibiting unmatched performance in the recall of known functional PTM sites and the recommendation of PTMs that were later confirmed experimentally. An analysis of feature contributions to model outcome provides further insight on the need for multiple rather than single features to capture the breadth of functional data in the public [email protected] InformationSee Tables S1-S6 & Figures S1-S4.

IGR J17503–2636: a candidate supergiant fast X-ray transient

The object IGR J17503–2636 is a hard X-ray transient discovered by INTEGRAL on 2018 August 11. This was the first ever reported X-ray emission from this source. Following the discovery, follow-up observations were carried out with Swift, Chandra, NICER, and NuSTAR. Here we report on the analysis of all of these X-ray data and the results obtained. Based on the fast variability in the X-ray domain, the spectral energy distribution in the 0.5–80 keV energy range, and the reported association with a highly reddened OB supergiant at ∼10 kpc, we conclude that IGR J17503–2636 is most likely a relatively faint new member of the supergiant fast X-ray transients. Spectral analysis of the NuSTAR data revealed a broad feature in addition to the typical power-law with exponential roll-over at high energy. This can be modeled either in emission or as a cyclotron scattering feature in absorption. If confirmed by future observations, this feature would indicate that IGR J17503–2636 hosts a strongly magnetized neutron star with B ∼ 2 × 1012 G.

Nitrogen-included Carbonaceous Compounds (NCC): Laboratory-synthesized organics as the probable candidate for the carrier of the UIR bands observed in dusty classical novae

The unidentified infrared (UIR) bands have been ubiquitously observed in various astrophysical environments and consist of a series of emission features arising from aromatic and/or aliphatic C-C and C-H bonds [1]. Therefore, their carriers are thought to be related to interstellar organics. However, our knowledge on the true carriers of the UIR bands is still limited. Recently [4] has proposed Mixed Aromatic Aliphatic Organic Nanoparticles, which contains hetero atoms in addition to conventional hydrocarbon models, as a more realistic interpretation of the band carriers. The challenges toward identifying the carriers of the UIR bands are still ongoing. Past studies have shown that the UIR bands observed around classical novae, which characterized by the presence of broad feature around 8μm[2], are somewhat different from those observed in other astrophysical environment. Here we report the success of experimentally synthesizing the organics called Nitrogen-included Carbonaceous Compounds (NCC; [7]) whose infrared properties can reproduce the UIR bands observed in classical novae.