An Ultra diffuse Galaxy in the NGC 5846 group from the VEGAS survey

Many ultra diffuse galaxies (UDGs) have now been identified in clusters of galaxies. However, the number of nearby UDGs suitable for detailed follow-up remain rare. Our aim is to begin to identify UDGs in the environments of nearby bright early-type galaxies from the VEGAS survey. Here we use a deep g band image of the NGC 5846 group, taken as part of the VEGAS survey, to search for UDGs. We found one object with properties of a UDG if it associated with the NGC 5846 group, which seems likely. The galaxy, we name NGC 5846$\_$UDG1, has an absolute magnitude of M$_g$ = -14.2, corresponding to a stellar mass of $\sim$10$^8$ M$_{\odot}$. It also reveals a system of compact sources which are likely globular clusters. Based on the number of globular clusters detected we estimate a halo mass that is greater than 8$\times$10$^{10}$ M$_{\odot}$ for UDG1.Comment: 5 pages, 4 figures, accepted for publication in A&

Use of Microcalorimetry to Determine the Costs and Benefits to Pseudomonas Putida Strain KT2440 of Harboring Cadmium Efflux Genes

A novel microcalorimetric approach was used to analyze the responses of a metal-tolerant soil bacterium (Pseudomonas putida strain KT2440) to metal resistance gene deletions in cadmium-amended media. As hypothesized, under cadmium stress, the wild-type strain benefited from the resistance genes by entering the exponential growth phase earlier than two knockout strains. In the absence of cadmium, strain KT1, carrying a deletion in the main component (czcA1) of a Cd/Zn chemiosmotic efflux transporter (CzcCBA1), grew more efficiently than the wild type and released similar to 700 kJ (per mole of biomass carbon) less heat than the wild-type strain, showing the energetic cost of maintaining CzcCBA1 in the absence of cadmium. A second mutant strain (KT4) carrying a different gene deletion, Delta cadA2, which encodes the main Cd/Pb efflux transporter (a P-type ATPase), did not survive beyond moderate cadmium concentrations and exhibited a decreased growth yield in the absence of cadmium. Therefore, CadA2 plays an essential role in cadmium resistance and perhaps serves an additional function. The results of this study provide direct evidence that heavy metal cation efflux mechanisms facilitate shorter lag phases in the presence of metals and that the maintenance and expression of tolerance genes carry quantifiable energetic costs and benefits

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Ultra diffuse galaxies in the Hydra I cluster from the LEWIS Project: Phase-Space distribution and globular cluster richness

Although ultra diffuse galaxies (UDGs) are found in large numbers in clusters of galaxies, the role of the cluster environment in shaping their low surface brightness and large sizes is still uncertain. Here we examine a sample of UDGs in the Hydra I cluster (D = 51 Mpc) with new radial velocities obtained as part of the LEWIS (Looking into the faintest with MUSE) project using VLT/MUSE data. Using a phase-space, or infall diagnostic, diagram we compare the UDGs to other known galaxies in the Hydra I cluster and to UDGs in other clusters. The UDGs, along with the bulk of regular Hydra I galaxies, have low relative velocities and are located near the cluster core, and thus consistent with very early infall into the cluster. Combining with literature data, we do not find the expected trend of GC-rich UDGs associated with earlier infall times. This result suggests that quenching mechanisms other than cluster infall should be further considered, e.g. quenching by strong feedback or in cosmic sheets and filaments. Tidal stripping of GCs in the cluster environment also warrants further modelling.Comment: 6 pages, 2 figures, MNRAS, 525, 9

Incidence and Tracking of Escherichia coli O157:H7 in a Major Produce Production Region in California

Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995–2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on implicated farms in the Salinas and San Juan valleys of California, and a survey of the Salinas watershed. EcO157 was isolated at least once from 15 of 22 different watershed sites over a 19 month period. The incidence of EcO157 increased significantly when heavy rain caused an increased flow rate in the rivers. Approximately 1000 EcO157 isolates obtained from cultures of>100 individual samples were typed using Multi-Locus Variable-number-tandem-repeat Analysis (MLVA) to assist in identifying potential fate and transport of EcO157 in this region. A subset of these environmental isolates were typed by Pulse Field Gel Electrophoresis (PFGE) in order to make comparisons with human clinical isolates associated with outbreak and sporadic illness. Recurrence of identical and closely related EcO157 strains from specific locations in the Salinas and San Juan valleys suggests that transport of the pathogen is usually restricted. In a preliminary study, EcO157 was detected in water at multiple locations in a low-flow creek only within 135 meters of a point source. However, possible transport up to 32 km was detected during periods of higher water flow associated with flooding. During the 2006 baby spinach outbreak investigation, transport was also detected where water was unlikely to be involved. These results indicate that contamination of the environment is a dynamic process involving multiple sources and methods of transport. Intensive studies of the sources, incidence, fate and transport of EcO157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human illness

Things that stay (and things that don't) : temporality and affect in collective memories of sexuality, bodies, and girlhood

In this chapter, Deleuzian-inspired approaches to temporality and duration are put to work to reconsider how memory operates in the intense collaborative space of collective biography (Davies & Gannon, 2006). We analyse two stories of teenage sexuality, tracing how what endures coheres in the body and travels across bodies in affective flows that disrupt any sense of linear or chronological time and collapses the discrete boundaries of individual subjectivities. Finally, we consider whether the particular technologies of speaking, listening, and writing that we take up in our work may serve to open up some memories and close others down. We conclude by noting the possibility of a continuing collective reticence around the young female body as a sexual, sexualized, and desiring subject

Girls, sexuality, and popular culture : "hey pony! come on!"

In this chapter, we turn to the entanglements of being and possibility that arise in girls’ everyday uses of popular texts. These narratives of memory show girls appropriating fragments of popular music, and fictional and non-fictional characters, and putting them to use in the serious play that is the focus of their daily lives. The narratives were generated in our collective biography workshop on sexuality and schooling in response to the prompt: “Remember a time when you made use of popular culture texts to learn about ‘doing girl’/’doing sexuality.’” We were interested in exploring agentic possibilities that arise for girls in sites of popular culture and how these might relate to normative discourses of heterosexuality. However, the analyses we present do not posit these girls as individualistic subjects who can easily enact new subjectivities, as they pick and choose new role models from media and textual resources. Nor do we promote an unconditional celebration of popular culture as a site of radical resistance in young people’s negation of identity. We understand, after Judith Butler, that subjects, including the girls evoked in the stories in this chapter, are always constituted within the discourses available to them, through repletion and citation of gendered practices and norms. The stories from the collective biography workshop show low possibilities for taking up, contesting, and countering hegemonic versions of femininity and girlhood arise within fluid and dynamic assemblages of bodies, texts, matters, and meanings

Deterritorializing collective biography

This paper proposes a new move in the methodological practice of collective biography, by provoking a shift beyond any remnant attachment to the speaking/ writing subject towards her dispersal and displacement via textual interventions that stress multivocality. These include the use of photographs, drama, and various genres of writing. Using a story selected from a collective biography workshop on sexuality and schooling, we document how we work across and among texts, thereby widening and shifting interpretive and subjective spaces of inquiry. We also consider how Deleuze and Guattari’s notions of territorialization/deterritorialization and the nomadic subject might be useful in theorizing such methodological moves in collective biography and our own investments in them