The optical and near-infrared properties of nearby groups of galaxies

We present a study of the optical (BRI) and near-infrared (JHK) luminosity fuctions (LFs) of the GEMS sample of 60 nearby groups of galaxies between 0<z<0.04, with our optical CCD photometry and near-IR photometry from the 2MASS survey. The LFs in all filters show a depletion of galaxies of intermediate luminosity, two magnitudes fainter than L*, within 0.3 R{500} from the centres of X-ray faint groups. This feature is not as pronounced in X-ray bright gropus, and vanishes when LFs are found out to R{500}, even in the X-ray dim groups. We argue that this feature arises due to the enhanced merging of intermediate-mass galaxies in the dynamically sluggish environment of low velocity-dispersion groups, indicating that merging is important in galaxy evolution even at z~0.Comment: to appear in the proceedings of the ESO workshop "Groups of Galaxies in the Nearby Universe", Santiago, Dec 5-9, 2005. Eds. I. Saviane, V. Ivanov, & J. Borissova (Springer Verlag); 5 page

A neighbourhood-scale conceptual model towards regenerative circularity for the built environment

There is potential in applying the circular economy (CE) and regenerative design (RD) models for the redevelopment of urban areas as a response to the current linear and mechanistic practices that still contribute to exceeding planetary boundaries and reinforcing social inequalities. Despite these models' common roots, they are usually approached quite differently. A merged approach may be able to solve existing gaps and critiques. This paper reviews relevant CE and RD definitions linked to the urban context. An inductive content analysis to map and discuss existing themes is conducted, leading to a set of five underpinning pillars. The resulting ‘Regenerative Circularity for the Built Environment’ conceptual model adopts a systemic and positive impact approach that is the steppingstone for the development of a practical tool aiming to support urban stakeholders in the transition of existing neighbourhoods with strategies more suitable to their aims and notion of place

A Future-Proof Built Environment through Regenerative and Circular Lenses—Delphi Approach for Criteria Selection

Despite the increasing use of neighbourhood sustainability assessment tools (NSAT), their linear approach may be insufficient to tackle the global and local social and ecological challenges. The circular economy (CE) has recently emerged as a new pathway, adopted by corporations and public organisations. Understanding how to apply CE to existing communities, while addressing some of its shortcomings, particularly the strong focus on resource management, is the main goal of this paper. Building upon a Regenerative Circularity for the Built Environment (RC4BE) conceptual model that merges circular economy and regenerative design concepts, a framework with criteria for its implementation in the transition of existing urban areas is proposed. A preliminary framework structure with criteria mapped from literature is proposed and validated through a 2-round Delphi consultation with 31 international experts. The final framework, with 136 criteria, addresses some of the identified gaps and different urban cycles related to physical resources, ecosystems, liveability, infrastructure, governance, participation, local economy, and other socioeconomic aspects of urban communities. This expanded take on CE should be useful for built environment professionals and other urban stakeholders interested in regenerating their communities and precincts by going beyond current green approaches and existing tools to effectively generate positive impact for people and the planet

Inquiry on Perceptions and Practices of Built Environment Professionals Regarding Regenerative and Circular Approaches

The circular economy and regenerative design approaches, although still emerging in the built environment, are important pathways to move away from the degenerative business-as-usual practices in the sector. In this paper, we investigate the perception, awareness, and practices of built environment professionals regarding the adoption of a combined regenerative circularity approach for buildings and cities, and if current practices and ‘neighbourhood sustainability assessment’ (NSA) tools should be improved and how. The inquiry was conducted using a convergent mixed methods approach with professionals from around the globe through: (a) online questionnaires which collected 146 responses, and (b) 18 semi-structured interviews which delved further into relevant aspects of the survey. Quantitative and qualitative responses were coded, grouped, and analysed. Results indicate an average awareness of topics with large space for improvement of practices. The main pathways for improvement for NSA tools include performance requirements, aspects of flexibility and adaptability, and engagement and communication, to which are added opportunities and enablers to improve the sector. The authors hope that this study will contribute towards the improvement and design of better tools and practices to support the implementation of regenerative circularity in the built environment sector

‘All in all it is just a judgement call’: issues surrounding sexual consent in young people’s heterosexual encounters

In the UK, there has been growing concern about young people’s understanding of sexual consent, with the views of young people themselves often lost in academic and educational policy debates. However, the focus on high rates of sexual violence has meant a lack of attention on the everyday negotiation of consensual heterosexual activity, leading to assumptions being made regarding young people’s lack of understanding of sexual consent. This paper emerges from a wider study of over 500 young people which sought to uncover their understanding of the issues. Drawing on data from workshops and the open text responses to an on-line survey the findings presented in this paper show that the majority of heterosexual young people understood the complexity of sexual consent as an embodied process, which can be difficult to define, talk about or practice uniformly. This complex understanding, in which sexual consent is a continuum rather than a dichotomy, has implications for sexual education initiatives. We argue that it is only by providing a closer understanding of how - within consensual sexual activities - young people understand and enact sexual consent through a range of embodied communication strategies that education surrounding sexual assault will become meaningful

XMM-Newton study of 0.012<z<0.024 groups. I: Overview of the IGM thermodynamics

We study the thermodynamic properties of the hot gas in a sample of groups in the 0.012-0.024 redshift range, using XMM-Newton observations. We present measurements of temperature, entropy, pressure and iron abundance. Non-parametric fits are used to derive the mean properties of the sample and to study dispersion in the values of entropy and pressure. The scaling of the entropy at 0.2r500 matches well the results of Ponman et al. (2003). However, compared to cool clusters, the groups in our sample reveal larger entropy at inner radii and a substantially flatter slope in the entropy in the outskirts, compared to both the prediction of pure gravitational heating and to observations of clusters. This difference corresponds to the systematically flatter group surface brightness profiles, reported previously. The scaled pressure profiles can be well approximated with a Sersic model with n=4. We find that groups exhibit a systematically larger dispersion in pressure, compared to clusters of galaxies, while the dispersion in entropy is similar.Comment: 11 pages, MNRAS in press, the 25 page version with all 176 figures included is at ftp://ftp.xray.mpe.mpg.de/people/alexis/2dxgs_astroph.ps.g

Community awareness of green roofs in Sydney

There are environmental, economic and social benefits of installing green roofs and walls on city buildings. The environmental benefits are lower building related operational carbon emissions, reductions in the urban heat island, increases in bio-diversity and reductions in storm-water run-off. Economically, the benefits are reduced roof maintenance costs, lower running costs, higher capital and rental values for commercial buildings. Finally the social or community gains are the creation of aesthetically pleasing spaces, landmarksand cultural capital as well as provision of recreational spaces. Furthermore social, psychological and therapeutic gains accrue when the roof or wall is visible to people andis used for social interaction and leisure activities. The perceived drawbacks are perceived greater risk of building leaks, high costs of installation and maintenance, and access and security issues. Whilst the technology to design and install green roofs and walls has existed for hundreds of years the uptake and the demand for green roofs and walls has not been high. Overall, the environmental social and economic gains are not perceived sufficient to create significant demand to set up green roofs and walls. In Sydney Australia, the existing number of green roofs and walls are testimony to this observation. With the aim of addressing the barriers to the uptake of green roofs and walls; it is essential to understand the way in which the key stakeholders; here the community, perceive the technology. With this knowledge it is then feasible to develop an agenda to mitigate any erroneous perceptions that exists. This research reports on a survey with the Sydney community to determine their perceptions of green roofs and walls

The unusual morphology of the intragroup medium in NGC 5171

We present the results of a 24 ks XMM-Newton observation of the NGC 5171 group of galaxies. NGC 5171 is unusual in that it is an X-ray bright group (L > 10^42 erg/s), with irregular contours which are not centred on a bright galaxy. The global spectrum is adequately described by a single temperature APEC model with T = 0.96 +/- 0.04 keV, and Z = 0.13 +/- 0.02 Zsol, in good agreement with previous ROSAT data. We find the X-ray contours are centred on a bright ridge of emission stretching from the BGG to a nearby galaxy. Spectral mapping reveals this ridge to be both cool (T ~ 1.1 keV) and metallic (Z ~ 0.4 Zsol) in comparison to its surrounding, suggesting it is the result of a tidal interaction between the two galaxies. Optical data reveals the member galaxies to have a high velocity dispersion (sigma = 494 +/- 99 km/s), and a significantly non-Gaussian velocity distribution, suggesting the group is in the process of merging. A region of hot gas with T = 1.58 +/- 0.36 keV is found to the West of the bright central ridge, and we interpret this as shock-heating resulting from the merging. A further region of emission to the South-East of the bright central ridge, with T = 1.14 +/- 0.13 keV, is probably associated with a background group, four times more distant.Comment: 10 pages, 8 figures, to be published in MNRA

Segregation Effects According to the Evolutionary Stage of Galaxy Groups

We study segregation phenomena in 57 groups selected from the 2PIGG catalog of galaxy groups. The sample corresponds to those systems located in areas of at least 80% redshift coverage out to 10 times the radius of the groups. The dynamical state of the galaxy systems was determined after studying their velocity distributions. We have used the Anderson-Darling test to distinguish relaxed and non-relaxed systems. This analysis indicates that 84% of groups have galaxy velocities consistent with the normal distribution, while 16% of them have more complex underlying distributions. Properties of the member galaxies are investigated taking into account this classification. Our results indicate that galaxies in Gaussian groups are significantly more evolved than galaxies in non-relaxed systems out to distances of about 4R200, presenting signficantly redder (B-R) color. We also find evidence that galaxies with M_R < -21.5 in Gaussian groups are closer to the condition of energy equipartition.Comment: 5 pages, 4 figures, accepted for publication in the MNRAS Letter