The WEBT BL Lacertae Campaign 2001 and its extension : Optical light curves and colour analysis 1994–2002

BL Lacertae has been the target of four observing campaigns by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we present UBVRI light curves obtained by theWEBT from 1994 to 2002, including the last, extended BL Lac 2001 campaign. A total of about 7500 optical observations performed by 31 telescopes from Japan to Mexico have been collected, to be added to the ∼15 600 observations of the BL Lac Campaign 2000. All these data allow one to follow the source optical emission behaviour with unprecedented detail. The analysis of the colour indices reveals that the flux variability can be interpreted in terms of two components: longer-term variations occurring on a fewday time scale appear as mildly-chromatic events, while a strong bluer-when-brighter chromatism characterizes very fast (intraday) flares. By decoupling the two components, we quantify the degree of chromatism inferring that longer-term flux changes imply moving along a ∼0.1 bluerwhen- brighter slope in the B − R versus R plane; a steeper slope of ∼0.4 would distinguish the shorter-term variations. This means that, when considering the long-term trend, the B-band flux level is related to the R-band one according to a power law of index ∼1.1. Doppler factor variations on a “convex” spectrum could be the mechanism accounting for both the long-term variations and their slight chromatism.Reig Torres, Pablo, [email protected]

Using the physical properties of artefacts to manage through‐life knowledge flows in the built environment: an initial exploration

Effective through‐life management of built facilities requires effective through‐life knowledge management to support it. The KIM (Immortal Information and Through‐Life Knowledge Management) project attempted to develop such an approach, based on a dichotomy of knowledge and information. Knowledge is conceived in terms of communities of practice. An initial philosophical analysis demonstrates deficiencies in this conception. Drawing inspiration from production theory, a tripartite analysis is offered, suggesting that knowledge flows consist of: social practices, information and physical properties. Literature on physical properties from design studies, production management and ethnomethodology is briefly reviewed to demonstrate the information bearing functions of physical properties. Fieldwork conforming to the unique adequacy requirement of methods was carried out on construction sites, in hotel and hospital facilities during the use stage of their life cycles. Safety barriers on construction sites were found to have informational properties beyond their function as a physical barrier. The quality of information delivered by wayfinding signs was found to depend upon both the physical placement of the signs in relation to the surrounding environment and the physical layout of the sign itself. It was found that social practices are institutionalized to repair the knowledge flow when the physically instantiated wayfinding system breaks down. Finally, through the investigation of practices surrounding emergency resuscitation equipment, it was found that if the physical properties of information are not designed to mesh with the work practices of the setting, this will lead to a breakdown in the knowledge flow. It is suggested that elements of knowledge management, ethnomethodology, production management and design studies might be integrated to form the basis of a hybrid discipline