Spectroscopic confirmation of the low-latitude object FSR 1716 as an old globular cluster

Star clusters are invaluable tracers of the Galactic components and the discovery and characterization of low-mass stellar systems can be used to appraise their prevailing disruption mechanisms and time scales. However, owing to the significant foreground contamination, high extinction, and still uncharted interfaces of the underlying Milky Way components, objects at low Galactic latitudes are notoriously difficult to characterize. Here, we present the first spectroscopic campaign to identify the chemodynamical properties of the low-latitude star cluster FSR 1716. While its photometric age and distance are far from settled, the presence of RR Lyrae variables indicates a rather old cluster variety. Using medium-resolution (R$\sim$10600) calcium triplet (CaT) spectroscopy obtained with the wide-field multi-fibre AAOmega instrument, we identified six member candidates with a mean velocity of $-30$ km s$^{-1}$ and a velocity dispersion of 2.5$\pm$0.9 km s$^{-1}$. The latter value implies a dynamic mass of $\sim$1.3$\times$10$^4$ M$_{\odot}$, typical of a low-mass globular cluster. Combined with our derived CaT metallicity of $-1.38\pm0.20$ dex, this object is finally confirmed as an old, metal-poor globular cluster.Comment: 5 pages, 4 figures, accepted for publication in Astronomy & Astrophysic

Exploring the nonlinear rheological behavior and optical properties of cellulose nanocrystal suspensions

Cellulose nanocrystals (CNCs), with their versatile properties, offer immense potential in a range of applications, whether used independently or as sustainable reinforcements in polymers. They also find utility as renewable rheology modifiers in industries such as cosmetics, paints, and foods, where precise control over rheological characteristics is crucial for factors like product stability, prevention of splattering, and efficient processing and transportation. To enhance their properties and unlock new applications, surface modification of CNCs is essential. However, studying flow-induced structuring requires the use of accurate and reliable analysis methods, particularly when dealing with fast and large deformations in suspensions, multiphase systems, and composites.This thesis presents a novel approach for studying the interactions between flow fields and CNCs by investigating nonlinear rheological parameters using a combination of Fourier-Transform rheology (i) and Polarized Light Imaging (PLI) techniques (ii). The utilization of (i) allows for the capture of nonlinear parameters that cannot be obtained through conventional rheological characterization. Concurrently, (ii) provides visual insights into flow-induced CNC structuring and optical properties.By employing these two distinct techniques, it becomes possible to discern alterations in the microstructure of CNCs, enabling the determination of critical concentrations for phase transitions, percolation, and gelation. To validate the proposed methodology, several different CNC systems were examined, categorized as either (1) self-assembling or (2) non-self-assembling CNC suspensions. These systems varied in terms of surface charge, concentrations, surface modification with azetidinium salts or monovalent counterions, and aspect ratio.This comprehensive investigation expands our understanding of CNC behavior under flow conditions and offers valuable insights into the rheological properties of CNC suspensions, potentially paving the way for the development of improved materials and applications in various industries

Rola słowa we współczesnej komunikacji na przykładzie twórczości Kathrin Röggli

Udostępnienie publikacji Wydawnictwa Uniwersytetu Łódzkiego finansowane w ramach projektu „Doskonałość naukowa kluczem do doskonałości kształcenia”. Projekt realizowany jest ze środków Europejskiego Funduszu Społecznego w ramach Programu Operacyjnego Wiedza Edukacja Rozwój; nr umowy: POWER.03.05.00-00-Z092/17-00

Dust properties of Z~2 infrared-luminous lyman break galaxies.

Lyman break galaxies (LBGs) are well-known indicators of star formation. By analyzing the dust of moderate redshift (z ~ 2) LBGs, we can further investigate the properties of these strongly star forming galaxies at an epoch when global star formation is expected to peak. Using data observed by the Herschel satellite, we derive far-infrared fluxes for our color-selected sample of LBGs in the GOODS-S field, including a subsample of infrared-luminous LBGs (ILLBGs). This is one of the first samples of UV dropouts/partial dropouts, which are also infrared-luminous, to be studied for their far-IR properties. Fitting modified Planck curves and model spectral energy distributions (SEDs), we make estimations for dust temperatures and masses for our ILLBGs. We find dust temperatures ranging from ~ 19-70 K, with masses ~ 5:2x10^6 to 3:3x10^9 M, and star formation rates on the order of ~10 M yr^-1

Cep290 and the Primary Cilium- Understanding the Protein\u27s Role in Ciliary Health and Disease

Mutations in CEP290 are associated with phenotypes ranging from early onset retinal degeneration to embryonic lethal, multisystem disease. The association of CEP290 with disease in multiple tissues is believed to be due to its role in stabilizing the primary cilium, an organelle found on almost every cell in the body whose involvement in human health and disease has only recently been identified. Like many ciliary proteins, CEP290’s exact function in this structure and how mutations affecting the protein lead to disease remains relatively unclear. Here, a proposed mechanism of CEP290-associated disease pathogenesis is explored, finding severity of CEP290-associated disease correlates with the amount of functional CEP290 protein predicted to result from a given patient’s genotype. In addition, a potential interaction between CEP290 and TTBK2, a kinase recently discovered to traffic to the base or the primary cilium before the onset of ciliogenesis, was observed, providing insight into a role of CEP290 in the early stages of cilium formation

Local Perspective on the Practices and Challenges of Migrant Integration: The Case of Warsaw

Poland is currently experiencing a transition with regard to migration trends. Foreign immigration, perceived until recently as a secondary issue by public administration, is on the increase. The largest groups of immigrants have traditionally included Ukrainians and the Vietnamese, although the country has not experienced a significant influx of foreigners arriving from Middle East and African countries. At present, Poland has no migration policy document in force and integrative actions are undertaken mostly by local governments, typically on an ad hoc basis. As Poland’s capital city, Warsaw plays a key role in governing diversity and implementing integrative actions. Significant challenges to immigrant integration include barriers to settlement and discrimination on the labour and housing market, along with a substantial rise in negative attitudes towards foreigners amongst members of Polish society. It is mainly this last aspect that is addressed by Warsaw’s local government, which prioritises educational and awareness-raising measures. It must be acknowledged that this is done in close cooperation with the non-governmental sector, where organisations with expertise in relevant fields are commissioned to perform many tasks. The main challenge of integrative actions at the local level is that these are mostly incoherent measures, which in most cases are not sufficient for the actual needs of immigrants. Hence, it is necessary to develop systemic solutions with sound, long-term financing. Moreover, in order for integration to be successful, it is essential to ensure the coordination of measures taken by public institutions at both central and local government level and to ensure the participation of immigrant communities in the development of public policies

Elemental Abundances in M31: Alpha and Iron Element Abundances from Low-Resolution Resolved Stellar Spectroscopy in the Stellar Halo

Measurements of [Fe/H] and [$\alpha$/Fe] can probe the minor merging history of a galaxy, providing a direct way to test the hierarchical assembly paradigm. While measurements of [$\alpha$/Fe] have been made in the stellar halo of the Milky Way, little is known about detailed chemical abundances in the stellar halo of M31. To make progress with existing telescopes, we apply spectral synthesis to low-resolution DEIMOS spectroscopy (R $\sim$ 2500 at 7000 Angstroms) across a wide spectral range (4500 Angstroms $<$ $\lambda$ $<$ 9100 Angstroms). By applying our technique to low-resolution spectra of 170 giant stars in 5 MW globular clusters, we demonstrate that our technique reproduces previous measurements from higher resolution spectroscopy. Based on the intrinsic dispersion in [Fe/H] and [$\alpha$/Fe] of individual stars in our combined cluster sample, we estimate systematic uncertainties of $\sim$0.11 dex and $\sim$0.09 dex in [Fe/H] and [$\alpha$/Fe], respectively. We apply our method to deep, low-resolution spectra of 11 red giant branch stars in the smooth halo of M31, resulting in higher signal-to-noise per spectral resolution element compared to DEIMOS medium-resolution spectroscopy, given the same exposure time and conditions. We find $\langle$[$\alpha$/Fe]$\rangle$ = 0.49 $\pm$ 0.29 dex and $\langle$[Fe/H]$\rangle$ = 1.59 $\pm$ 0.56 dex for our sample. This implies that---much like the Milky Way---the smooth halo of M31 is likely composed of disrupted dwarf galaxies with truncated star formation histories that were accreted early in the halo's formation.Comment: 21 pages, 14 figures, accepted to Ap

Elemental Abundances in M31: A Comparative Analysis of Alpha and Iron Element Abundances in the the Outer Disk, Giant Stellar Stream, and Inner Halo of M31

We measured [Fe/H] and [α/Fe] using spectral synthesis of low-resolution stellar spectroscopy for 70 individual red-giant-branch stars across four fields spanning the outer disk, Giant Stellar Stream (GSS), and inner halo of M31. Fields at M31-centric projected distances of 23 kpc in the halo, 12 kpc in the halo, 22 kpc in the GSS, and 26 kpc in the outer disk are α-enhanced, with ⟨ [α/Fe]〉= 0.43, 0.50, 0.41, and 0.58, respectively. The 23 and 12 kpc halo fields are relatively metal-poor, with ⟨ [Fe/H]⟩ = −1.54 and −1.30, whereas the 22 kpc GSS and 26 kpc outer disk fields are relatively metal-rich with ⟨ [Fe/H]⟩ = −0.84 and −0.92, respectively. For fields with substructure, we separated the stellar populations into kinematically hot stellar halo components and kinematically cold components. We did not find any evidence of a radial [α/Fe] gradient along the high surface brightness core of the GSS between ~17 and 22 kpc. However, we found tentative suggestions of a negative radial [α/Fe] gradient in the stellar halo, which may indicate that different progenitor(s) or formation mechanisms contributed to the build up of the inner versus outer halo. Additionally, the [α/Fe] distribution of the metal-rich ([Fe/H] > −1.5), smooth inner stellar halo (r_(proj) ≾ 26 kpc) is inconsistent with having formed from the disruption of a progenitor(s) similar to present-day M31 satellite galaxies. The 26 kpc outer disk is most likely associated with the extended disk of M31, where its high α-enhancement provides support for an episode of rapid star formation in M31's disk possibly induced by a major merger

High pressure infrared studies of HMX

We are studying the effects of pressure on HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) using infrared spectroscopy. The sample is put under pressure using a diamond anvil cell at ambient temperature, data is collected at the National Synchrotron Light Source in Brookhaven National Laboratory. In analyzing this data, we hope to learn more about the molecular vibrations as the molecule bends and deforms under pressure. Such understanding could aid in determining new safety standards or more efficient ways of using HMX. In future studies, we intend to include the aspect of temperature variation in addition to pressure, with the goal of describing the molecule in a phase diagram