A comparison of metrics proposed for circadian lighting and the criterion adopted in the WELL Building Standard.

Since the discovery that intrinsically photosensitive retinal ganglion cells influence the body’s circadian rhythms, there has been a desire to quantify this effect in terms helpful to lighting designers. The effect of lighting on occupants’ circadian rhythms has implications for their health and well-being, and, for the workplace, this can affect productivity and absenteeism. There is not yet a universally agreed way to account for how different lighting choices might determine these effects. Various models have been proposed that attempt to quantify, at least relatively, these effects; in each case adopting some form of action spectrum associated with melatonin suppression, as this hormone is known to be critical in the circadian process. It is has been established that the effects vary according to the wavelength of the light, and the total effect is normally modelled as a weighted sum, despite evidence that effects from different wavelengths combine non-linearly or even in opposition. Different metrics are compared for various real light sources but these are shown not to agree, thus different design choices would be made according to the model adopted. The WELL Building Standard has adopted the use of Equivalent Melanopic Lux to formulate lighting criteria. Consequences for the selection of light sources and the specification of internal illuminance are examined

Day-ahead forecasting of grid carbon intensity in support of HVAC plant demand response decision-making to reduce carbon emissions

Electrical HVAC loads in buildings are suitable candidates for use in demand response activity. This paper demonstrates a method to support planned demand response actions intended explicitly to reduce carbon emissions. Demand response is conventionally adopted to aid the operation of electricity grids and can lead to greater efficiency; here it is planned to target times of day when electricity is generated with high carbon intensity. Operators of HVAC plant and occupants of conditioned spaces can plan when to arrange shutdown of plant once they can foresee the opportune time of day for carbon saving. It is shown that the carbon intensity of the mainland UK electricity grid varies markedly throughout the day, but that this tends to follow daily and weekly seasonal patterns. To enable planning of demand response, 24-hour ahead forecast models of grid carbon intensity are developed that are not dependent on collecting multiple exogenous data sets. In forecasting half-hour periods of high carbon intensity either linear autoregressive or non-linear ANN models can be used, but a daily seasonal autoregressive model is shown to provide a 20% improvement in carbon reduction

Energy saving claims for lighting controls in commercial buildings

Lighting systems consume a significant proportion of the energy used in commercial buildings, and the control of lighting use is an important determinant of the energy performance of buildings. A review and meta-analysis of lighting energy studies in commercial premises is undertaken to investigate difficulties with reported energy-saving claims for popular lighting control methods. Earlier studies have indicated that in some installations automated controls may save very little energy if they are replacing manual control. However, even where manual control would be a reasonable expectation, such as in private offices, it has been common practice to report saving in energy compared to the lights being used throughout the working day, which leads to overstatement of the energy-saving potential. However, generally, user behaviour cannot be reliably predicted, which makes it difficult to quantify properly the benefits of adding automatic controls. It is argued that savings should instead be quantified with reference to published norms for lighting use in commercial buildings

The Exhibition as an Experiment: An Analogy and its Implications

The analogy of the exhibition as an experiment suggests innovative curatorial approaches that challenge institutional practices. This analogy has however a historical precedence in modernism when itbecame paradigmatic of the exhibitions at the Museum of ModernArt in New York in the 1940s, defining the curatorial approach of its founding director Alfred J Barr. This article considers this early useof the analogy of the exhibition as an experiment and further reflects on its redefinition at the turn of the 20th century by examining how both the notions of the exhibition and of the experiment havechanged over time. In particular, the article examines the different meanings and practices inferred by the concepts of the exhibition and the experiment in the first decades of the 20th century and in the present. It outlines how correspondences between cultural and scientific paradigms can be deployed to tease unacknowledged synergies between two modes of knowledge production (i.e. the art exhibition and the experiment) and address questions of presentness, authority and legitimacy that they imply

Effect of tamoxifen on hepatic regeneration in male rats

A number of metabolic changes within the liver occur concurrent with hepatic regeneration. These processes suggest that the administration of an antiestrogen might alter the rate of hepatic regeneration. To examine this question, male Wistar rats were treated with tamoxifen (0.1 mg/rat/day or 1.0 mg/rat/day) or vehicle for three days prior to and after partial hepatectomy, and the anatomic and biochemical process of hepatic regeneration was assessed. Tamoxifen administration caused a dose-dependent decrease in the hepatic cytosolic estrogen receptor activity and, conversely, a dose-dependent increase in cytosolic androgen receptor activity. Despite these changes in baseline hepatic sex steroid receptor status, all receptor activities were comparable between the three groups within 24 hr of partial hepatectomy. Moreover, no differences in any of the the parameters assessing hepatic regeneration following partial hepatectomy were evident: liver-body ratio, ornithine decarboxylase activity, and thymidine kinase activity. This lack of effect of tamoxifen treatment on hepatic regeneration suggests either that estrogens do not play a role in the modulation of liver growth after partial hepatectomy or that, once initiated, the regenerative process per se determines a series of events that regulate hepatocellular sex hormone receptor status independent of extrahepatic stimuli. © 1989 Plenum Publishing Corporation

Chronic hypothermia and energy expenditure in a neurodevelopmentally disabled patient: a case study

Hypothermia is defined as a core body temperature of \u3c35°C and results in a decrease in measured resting energy expenditure. A 51-year-old mentally disabled patient experienced chronic hypothermia from neurologic sequelae. Because of her continued weight gain and increased body fat in the presence of presumed hypocaloric nutrition, indirect calorimetry measurements were performed twice in a 3-month period. The resting energy expenditure measurements prompted a reduction of her daily caloric intake to prevent further overfeeding. Hypothermia reduces oxygen consumption and, as a consequence, decreases resting energy expenditure. In patients for whom chronic hypothermia is a problem, nutritional intake must be adjusted to prevent overfeeding, excessive weight gain, and the long-term complications of an excess of total calories

A Literature Review Outlining the Importance of Blinds and Shutters as a Sustainable Asset that has the Potential to enhance the Productivity of Occupants in the UK

Blinds and Shutters in the UK are still thought of as an optional window dressing rather than a low cost sustainable building asset that can enhance a window/glazing system’s performance and in return, save energy through passive thermal measures and measurable solar performance. Although the array of benefits is validated for blinds and shutters there are historic barriers to realising the potential for saving energy. Simple behavioural change related to the use of existing products would be a no cost productivity and energy benefit. Use of blinds and shutters is based on the need of a variety of factors in both commercial and domestic markets. These factors can be categorized into three broad areas namely energy savings, comfort (inclusive of visual, thermal and acoustic preferences) and occupant satisfaction which contribute to improving the health, well-being and productivity of occupants. In recent publications it has been demonstrated how thermal, visual, acoustic and controllability of occupants’ working environments impacts productivity. The business case for linking productivity to ‘green’ working environments has been made by the World Green Building Council (WGBC) highlighting how productivity of staff is a greater incentive for commercial buildings to become more sustainable. This study incorporates a literature review of the sustainable benefits of shading and illustrates how they are an asset to the building façade in creating dynamic, comfortable and potentially productive environments for the commercial sector. However, we highlight the difficulties of this research and outline a potential future study

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta