12/18/2023 0 Comments Negative feedback examples physics![]() On the one hand these objects show the most conspicuous cases for outflows in the local Universe (e.g., Heckman et al., 2000 Rupke et al., 2002). In this context, local Luminous and Ultra-Luminous Infrared Galaxies are particularly interesting populations. ![]() Although the bulk of the black hole growth, SF, and galaxy mergers are believed to occur at z ~ 1–3, studies of outflows in nearby galaxies offer detailed insights into feedback phenomena as one of the primary drivers of galaxy evolution. Multiphase outflows are ubiquitous at any redshift. In this context, the study of the of feedback mechanisms is of critical importance to trace the build-up of stellar mass and evolution of galaxies in the Universe. In addition, it has been recently proposed that outflows can undergo vigorous SF (positive feedback, Ishibashi and Fabian, 2012 Zubovas et al., 2013). Outflows regulate Star Formation (SF) and AGN activity (negative feedback), and they are also considered the primary mechanism by which dust and metals are redistributed over large scales in the Inter Stellar Medium (ISM), or even expelled outside the galaxy into the IGM (e.g., Aguirre et al., 2001). In fact, models of galaxy evolution without a strong (stellar or AGN) feedback, lead galaxies to have much higher Star Forming Rates (SFR) and larger stellar masses than observed (e.g., Hopkins et al., 2006). ![]() Galaxy evolution models attempt to reproduce the properties of the galaxies and those of the surrounding Inter Galactic Medium (IGM) invoking the need of feedback mechanisms from starbursts or Active Galactic Nuclei (AGN). These surveys have drawn a detailed picture of the global properties of the galaxies, establishing the galaxy stellar mass function and scaling relations (e.g., mass-metallicity, Tremonti et al., 2004 Brooks et al., 2006). The researchers hope to continue and expand the study to include more domestic cats as well as other species of cats.Īdditional co-authors on the study, all at UC Davis, are: David Coil, Genome Center Stanley Marks, School of Veterinary Medicine Eva Borras, Mitchell McCartney and Cristina Davis, Department of Mechanical and Aerospace Engineering and UC Davis Lung Center and Hira Lesea, Department of Microbiology and Molecular Genetics.In the last decade, our understanding of the formation and evolution of galaxies over cosmic time has been significantly enhanced by large scale galaxy surveys. Genetic analysis showed that the bacteria living in the anal gland could be responsible for making these compounds. Looking at the chemicals produced in the anal glands, the researchers detected hundreds of organic compounds. Microbial populations might also be affected by factors such as the cat's diet, health conditions and its overall living environment. There were also some apparent differences in cats assessed as obese, but the sample size was not large enough to confirm this. Older cats generally had a different microbiome from younger animals. Owners gave written permission for their cats to take part in the study.įive genera of bacteria (Corynebacterium, Bacteroides, Proteus, Lactobacillus and Streptococcus) dominated overall, but the microbial makeup was highly variable between individual cats. ![]() The subjects in the study were 23 domestic cats seen at the UC Davis Veterinary Medical Teaching Hospital for elective procedures such as dental cleaning. They used DNA sequencing, mass spectrometry and microbial culturing to look at the chemicals in the secretions and the microbes that make them. They mark territory, attract mates and repel rivals.Ĭonnie Rojas, a postdoctoral researcher working with Professor Jonathan Eisen at the UC Davis Department of Evolution and Ecology and Genome Center, led a three-part study of anal gland secretions from domestic cats. ![]() While mostly undetectable to human noses, these scents are important in cats' behavior and social lives. The study adds to a growing body of research on the relationship between microbes and odor in mammals, including domestic dogs, wild animals such as foxes, pandas and hyenas, and humans.Ĭats' scent comes from a mix of volatile organic compounds, including aldehydes, alcohols, esters and ketones. ![]()
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