Rural adolescent risk behaviors :: towards an understanding of their nature and associated family factors.

Thesis (M.S.

Discovery of a massive supercluster system at z∼0.47z \sim 0.47

Superclusters are the largest relatively isolated systems in the cosmic web. Using the SDSS BOSS survey we search for the largest superclusters in the redshift range $0.43<z<0.71$. We generate a luminosity-density field smoothed over $8 h^{-1}\mathrm{Mpc}$ to detect the large-scale over-density regions. Each individual over-density region is defined as single supercluster in the survey. We define the superclusters in the way that they are comparable with the superclusters found in the SDSS main survey. We found a system we call the BOSS Great Wall (BGW), which consists of two walls with diameters 186 and 173 $h^{-1}$Mpc, and two other major superclusters with diameters of 64 and 91 $h^{-1}$Mpc. As a whole, this system consists of 830 galaxies with the mean redshift 0.47. We estimate the total mass to be approximately $2\times10^{17}h^{-1}M_\odot$. The morphology of the superclusters in the BGW system is similar to the morphology of the superclusters in the Sloan Great Wall region. The BGW is one of the most extended and massive system of superclusters yet found in the Universe.Comment: 4 pages, accepted as a letter in A&

Deep Sequencing Analysis of RNAs from Citrus Plants Grown in a Citrus Sudden Death-Affected Area Reveals Diverse Known and Putative Novel Viruses.

Citrus sudden death (CSD) has caused the death of approximately four million orange trees in a very important citrus region in Brazil. Although its etiology is still not completely clear, symptoms and distribution of affected plants indicate a viral disease. In a search for viruses associated with CSD, we have performed a comparative high-throughput sequencing analysis of the transcriptome and small RNAs from CSD-symptomatic and -asymptomatic plants using the Illumina platform. The data revealed mixed infections that included Citrus tristeza virus (CTV) as the most predominant virus, followed by the Citrus sudden death-associated virus (CSDaV), Citrus endogenous pararetrovirus (CitPRV) and two putative novel viruses tentatively named Citrus jingmen-like virus (CJLV), and Citrus virga-like virus (CVLV). The deep sequencing analyses were sensitive enough to differentiate two genotypes of both viruses previously associated with CSD-affected plants: CTV and CSDaV. Our data also showed a putative association of the CSD-symptomatic plants with a specific CSDaV genotype and a likely association with CitPRV as well, whereas the two putative novel viruses showed to be more associated with CSD-asymptomatic plants. This is the first high-throughput sequencing-based study of the viral sequences present in CSD-affected citrus plants, and generated valuable information for further CSD studies

Variable Stars in Local Group Galaxies. IV. RR Lyrae stars in the central regions of the low-density galaxy Crater II

We present a search and analysis of variable stars in the recently discovered Crater~II dwarf galaxy. Based on $B$, $V$, $I$ data collected with the Isaac Newton Telescope (FoV$\sim$0.44 square degrees) we detected 37 variable stars, of which 34 are bone-fide RR Lyrae stars of Crater~II (28 RRab, 4 RRc, 2 RRd). We applied the metal-independent ($V$, $B-V$) Period--Wesenheit relation and derived a true distance modulus ($\mu$ = 20.30$\pm$0.08 mag ($\sigma$=0.16 mag). Individual metallicities for RR Lyrae stars were derived by inversion of the predicted $I$-band Period-Luminosity relation. We find a mean metallicity of [Fe/H]=-1.64 and a standard deviation of $\sigma_{[Fe/H]}$ =0.21 dex, compatible with either negligible or vanishing intrinsic metallicity dispersion. The analysis of the Colour-Magnitude Diagram reveals a stark paucity of blue horizontal branch stars, at odds with other Galactic dwarfs, and globular clusters with similar metal abundances.Comment: 14 pages, 8 figures, accepted for publications on MNRAS. Time series photometry is available in the manuscript source ta

Vnímání, kauzalita a pozornost Roger Bacon a Petr Olivi

[Sensation, Causality, and Attention: Roger Bacon and Peter Olivi] This paper investigates what conditions are to be met for sensory perception to occur. It introduces two diff erent theories of perception that were held by two medieval Franciscan thinkers — namely, Roger Bacon (1214/1220–1292) and Peter Olivi (ca. 1248–1298). Bacon analyses especially the causal relation between the object and the sensory organ in his doctrine of the multiplication of species. In his view, a necessary condition of perception is the reception of the species in a fully disposed sensory organ. On the contrary, Olivi stresses the active role of the sensory power. A necessary condition of sensation is the aspectus — i.e. the focus of our power’s attention on the object. Furthermore, the paper investigates whether and how each of the two thinkers can deal with the arguments proposed by his opponent — namely whether Bacon’s theory is able to explain attention and what the causal role of the object in Olivi’s theory is

The effect of substituents on the syn-anti conformer ratio in naphthyl-based imidazolinium salts and their corresponding N-heterocyclic carbenes

Eight new N-heterocyclic carbenes (NHCs) featuring substituted naphthyl side chains were synthesized. These molecules are present in solution as a stable mixture of antiand synconformers. Through careful tuning of the substituents on position 2 and 2,7 of the naphthyl moieties, it was possible to synthesize molecules that display a strong preference for the anticonformation (up to 95:5). This will greatly facilitate their optimized use as single isomeric ligands in metal-catalysis and as organocatalysts

The galaxy size - halo mass scaling relations and clustering properties of central and satellite galaxies

In this work, we combine size and stellar mass measurements from the Sloan Digital Sky Server (SDSS) with the group finder algorithm of Rodriguez \& Merch\'an in order to determine the stellar and halo mass -- size relations of central and satellite galaxies separately. We show that, while central and satellite galaxies display similar stellar mass -- size relations, their halo mass -- size relations differ significantly. As expected, more massive haloes tend to host larger central galaxies. However, the size of satellite galaxies depends only slightly on halo virial mass. We show that these results are compatible with a remarkably simple model in which the size of central and satellite galaxies scales as the cubic root of their host halo mass, with the normalization for satellites being $\sim$ 30 \% smaller than that for central galaxies, which can be attributed to tidal stripping. We further check that our measurements are in excellent agreement with predictions from the IllustrisTNG hydrodynamical simulation. In the second part of this paper, we analyse how the clustering properties of central and satellite galaxies depend on their size. We demonstrate that, independently of the stellar mass threshold adopted, smaller galaxies are more tightly clustered than larger galaxies when either the entire sample or only satellites are considered. The opposite trend is observed on large scales when the size split is performed for the central galaxies alone. Our results place significant constraints for halo-galaxy connection models that link galaxy size with the properties of their hosting haloes.Comment: 15 pages, 12 figures. Accepted for publication in MNRA

Measuring the growth of structure by matching dark matter haloes to galaxies with VIPERS and SDSS

We test the history of structure formation from redshift 1 to today by matching galaxies from the VIMOS Public Extragalactic Redshift Survey (VIPERS) and Sloan Digital Sky Survey (SDSS) with dark matter haloes in the MultiDark, Small MultiDark Planck (SMDPL), N-body simulation. We first show that the standard subhalo abundance matching (SHAM) recipe implemented with MultiDark fits the clustering of galaxies well both at redshift 0 for SDSS and at redshift 1 for VIPERS. This is an important validation of the SHAM model at high redshift. We then remap the simulation time steps to test alternative growth histories and infer the growth index gamma = 0.6 +/- 0.3. This analysis demonstrates the power of using N-body simulations to forward model galaxy surveys for cosmological inference. The data products and code necessary to reproduce the results of this analysis are available online (https://github.com/darklight- cosmology/vipers-sham)

Acinar cell carcinoma of the pancreas with thyroid-like follicular features: first description of a new diagnostic challenging subtype.

Acinar cell carcinomas (ACCs) of the pancreas are a heterogeneous group of neoplasms showing a wide spectrum of morphological features including acinar, solid, glandular, and trabecular architecture. In addition, uncommon cytological aspects have recently been described and include oncocytic, spindle, clear, and pleomorphic cell types. This wide histological spectrum represents a challenge in the diagnostic task for pathologists. Molecular mechanisms involved in the onset and progression of ACCs are not completely known, but, in general, they differ from those observed in ductal adenocarcinomas or neuroendocrine neoplasms of the pancreas and frequently include alterations in the APC/β-catenin pathway. In the present paper, we describe a new variant of ACC showing thyroid-like follicular features and CTNNB1 mutation. This phenotype needs to be included in the spectrum of morphological presentation of ACC