Evolution of human chromosome 7: new information from the mapping of Williams- Beuren locus on non-human primates chromosomes

Human chromosome 7 (HSA7) derives, by a pericentric inversion and a paracentric inversion, from an ancestral chromosome homologous to chromosome 10 of Pongo pygmaeus (the Asiatic Orang-Utan). Nevertheless the genesis of this autosome during primates evolution is not clear. Even if chromosome painting shows that HAS 7 synteny is highly conserved, GTG-banding comparison in Hominoidea and Cercopithecoidea indicates the probable occurrence of complex rearrangements during the evolution. In this study we used a single locus FISH approach, a powerful tool to detect fine rearrangements, in order to investigate the evolution of HAS 7. We report the chromosome mapping of Williams-Beuren syndrome locus (WS - HSA 7q11.23) on Macaca fascicularis (MFA), Cercopithecus (Chlorocebus) aethiops (CAE) and Trachypithecus cristatus (TCR) (Cercopithecoidea, Primates). The probe hybridises on all species tested and demonstrates the occurrence of rearrangements like fusion, fission and pericentric plus paracentric inversions respectively in MFA, CAE and TCR. Together with the first chromosome mapping of WS locus in Cercopithecoidea, this study confirms that single locus mapping is a very efficacious tool for the analysis of chromosomal rearrangements as it gave the opportunity to have a fine molecular confirmation to proposed banding patterns homologies

Teaching as a system: COVID-19 as a lens into teacher change

In the spring of 2020, schools and universities around the world were closed because of the COVID-19 pandemic. The relative lockdown affected more than 1.5 billion learners as teachers and students sheltered at home for several weeks. As schooling moved online, teachers were forced to change how they taught. In the research presented here, we focus on university mathematics professors, and we analyze how their practice, knowledge, and beliefs intertwine and change under these circumstances. More specifically, the context of the pandemic and the relative lockdown provides us with the experimental basis to argue that the new practice affected both knowledge and beliefs of mathematics teachers and that practice, knowledge, and beliefs form a system. Being part of a system, the reactions to change in practice can be of two types, namely, the system as a whole tries to resist change, or the system as a whole changes - and it changes significantly. The research presented here proposes a model for describing and analyzing what we called a teaching system and examines three cases that help to better depict the systemic nature of teaching

Cellular-Automata model for dense-snow avalanches

This paper introduces a three-dimensional model for simulating dense-snow avalanches, based on the numerical method of cellular automata. This method allows one to study the complex behavior of the avalanche by dividing it into small elements, whose interaction is described by simple laws, obtaining a reduction of the computational power needed to perform a three-dimensional simulation. Similar models by several authors have been used to model rock avalanches, mud and lava flows, and debris avalanches. A peculiar aspect of avalanche dynamics, i.e., the mechanisms of erosion of the snowpack and deposition of material from the avalanche is taken into account in the model. The capability of the proposed approach has been illustrated by modeling three documented avalanches that occurred in Susa Valley (Western Italian Alps). Despite the qualitative observations used for calibration, the proposed method is able to reproduce the correct three-dimensional avalanche path, using a digital terrain model, and the order of magnitude of the avalanche deposit volume

Recuperação e distribuição do nitrogênio fornecido a videiras jovens.

O objetivo deste trabalho foi estimar a recuperação e a distribuição do N fornecido a videiras jovens. O experimento foi realizado em casa de vegetação na Embrapa Uva e Vinho, Bento Gonçalves, RS. Foram utilizadas videiras da cultivar Riesling Itálico e Chardonnay, enxertadas no porta-enxerto 101-14 Mgt. Foi cultivada uma planta por vaso contendo 3,5 kg de um Neossolo Litólico. A solução de sulfato de amônio com 2% de átomos 15N, na dose de 185,60 mg de N foi aplicada na superfície do solo depois do transplante das videiras. As plantas foram coletadas em seis épocas, e separadas em folhas, porta-enxerto + enxerto, raízes grossas e finas. Todas as partes das videiras foram secadas em estufa, para determinação da produção de matéria seca e análise do N total e 15N. A maior recuperação do N do fertilizante pelas videiras jovens ocorreu em épocas próximas ao fornecimento do N. A maior quantidade de N acumulado nas videiras derivou-se de formas diferentes daquelas do N fornecido. As folhas e raízes foram o maior compartimento de N total e N derivado do fertilizante

A Peculiar Family of Jupiter Trojans: the Eurybates

The Eurybates family is a compact core inside the Menelaus clan, located in the L4 swarm of Jupiter Trojans. Fornasier et al. (2007) found that this family exhibits a peculiar abundance of spectrally flat objects, similar to Chiron-like Centaurs and C-type main belt asteroids. On the basis of the visible spectra available in literature, Eurybates family's members seemed to be good candidates for having on their surfaces water/water ice or aqueous altered materials. To improve our knowledge of the surface composition of this peculiar family, we carried out an observational campaign at the Telescopio Nazionale Galileo (TNG), obtaining near-infrared spectra of 7 members. Our data show a surprisingly absence of any spectral feature referable to the presence of water, ices or aqueous altered materials on the surface of the observed objects. Models of the surface composition are attempted, evidencing that amorphous carbon seems to dominate the surface composition of the observed bodies and some amount of silicates (olivine) could be present.Comment: 23 pages, 2 figures, paper accepted for publication in Icaru

Methane and Nitrogen Abundances On Pluto and Eris

We present spectra of Eris from the MMT 6.5 meter telescope and Red Channel Spectrograph (5700-9800 angstroms; 5 angstroms per pix) on Mt. Hopkins, AZ, and of Pluto from the Steward Observatory 2.3 meter telescope and Boller and Chivens spectrograph (7100-9400 angstroms; 2 angstroms per pix) on Kitt Peak, AZ. In addition, we present laboratory transmission spectra of methane-nitrogen and methane-argon ice mixtures. By anchoring our analysis in methane and nitrogen solubilities in one another as expressed in the phase diagram of Prokhvatilov and Yantsevich (1983), and comparing methane bands in our Eris and Pluto spectra and methane bands in our laboratory spectra of methane and nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are about 10% and about 90%, and Pluto's bulk methane and nitrogen abundances are about 3% and about 97%. Such abundances for Pluto are consistent with values reported in the literature. It appears that the bulk volatile composition of Eris is similar to the bulk volatile composition of Pluto. Both objects appear to be dominated by nitrogen ice. Our analysis also suggests, unlike previous work reported in the literature, that the methane and nitrogen stoichiometry is constant with depth into the surface of Eris. Finally, we point out that our Eris spectrum is also consistent with a laboratory ice mixture consisting of 40% methane and 60% argon. Although we cannot rule out an argon rich surface, it seems more likely that nitrogen is the dominant species on Eris because the nitrogen ice 2.15 micron band is seen in spectra of Pluto and Triton.Comment: The manuscript has 44 pages, 15 figures, and four tables. It will appear in the Astrophysical Journa

Cobre em solos cultivados com a videira na Serra Gaúcha do Rio Grande do Sul.

O presente trabalho objetivou determinar as formas de cobre e a cinética de dessorção em solos cultivados com a videira e submetidos a sucessivas aplicações de fungicidas cúpricos.bitstream/CNPUV/10103/1/cot086.pd

Lixiviação de nitrogênio em um Cambissolo cultivado com pessegueiro e submetido à aplicação de composto orgânico.

A aplicação de composto orgânico em solos cultivados com pessegueiro pode potencializar a transferência de N por lixiviação. O trabalho objetivou avaliar a lixiviação de N em um solo cultivado com pessegueiro e submetido à aplicação de composto orgânico. Em um pomar comercial de pessegueiro no município de Bento Gonçalves (RS) foram instalados lisímetros a 20 cm de profundidade. O solo recebeu a aplicação de 0 e 144 litros de composto orgânico por planta-1 ano-1 nas safras de 2010, 2011 e 2012. A solução do solo foi coletada no período de julho a outubro de 2012 e submetida à análise de nitrato, amônio e N mineral. As maiores concentrações de N lixiviado foram encontradas no tratamento com 144 litros de composto orgânico por planta-1. A adubação com composto orgânico apresentou baixas concentrações de N lixiviado, o que pode contribuir com a redução de contaminação ambiental.Resumo expandido