Uncharted territory: daylight performance and occupant behaviour in a live classroom environment

In 2013, in an effort to improve the visual environment in future schools, a UK regulation specified mandatory daylight evaluations using, for the first time, climate-based metrics. Existing research on the daylighting performance of classrooms is limited and challenged by poor light measurement instrumentation, as well as the practicalities of the ‘live’ classroom setting. This paper describes an ongoing project aimed at providing evidence that will improve the understanding of how building occupants perceive daylight; how they respond to daylight performance due to the building design; and how their needs and actions shape the actual daylight performance of classrooms. A mixed method qualitative and quantitative approach is presented for the investigation of the aforementioned in four classrooms located in two secondary schools in the UK. Previously mentioned challenges are addressed by employing a High Dynamic Range imaging technique for monitoring physical data and the behaviour (blind and electric light use) of the occupants. The challenges encountered in the current study are discussed

Let there be daylight? Assessing actual daylighting performance of a classroom in use

Daylight is a non-depleting energy source with the potential to reduce building energy consumption and contribute to the health and wellbeing of building occupants. The increased reliance on daylight simulation tools, for the prediction of indoor daylighting performance, calls for sound benchmarking based on data from actual spaces in-use. However, due to practicalities such data are limited especially in the case of classrooms. The mixed method study presented here took a user-centred approach to investigate the relationship between three aspects of evidence collected from the real world: monitored illumination data; observed user interactions with the space and its systems (visual display technologies, electric lights, blinds); and user subjective responses. A UK classroom was used as a case study and was monitored for three months between September and December. High Dynamic Range (HDR) imaging was the technique used to provide (at a 10-minute interval) physical measurements of the luminous environment and data on the actions users took to maintain or improve visual comfort. A questionnaire (n=117) recorded the students’ subjective responses to the luminous environment. Findings from the combined study of these datasets lead to a deeper understanding of the occupants’ current visual needs and their perception of daylight, which is necessary for the development of realistic daylighting performance – and subsequently whole-building energy predictions

Reality bites: measuring actual daylighting performance in classrooms

Climate-based daylight modelling (CBDM) is providing the basis for yearlong indoor daylighting performance predictions. However, evidence of long-term actual daylighting performance of indoor spaces in use is limited. Since 2013, CBDM has been a mandatory requirement for the approval of school designs that fall under the UK’s £6 billion Priority Schools Building Programme. Specifying daylight compliance of schools with CBDM metrics increases the urgency for evidence of actual performance of classrooms. This paper describes a method for long-term monitoring of classrooms in use. It also identifies the key confounding factors that make the validation of CBDM metrics in practice a daunting task. Two UK classrooms are used as case studies and are monitored daily for six months with a 10-minute resolution. Using a robust method, based on High Dynamic Range (HDR) imaging, this work makes a case for the significance of real world daylighting performance measurements. Moreover it provides an overview of the first steps toward the evaluation of the practical application of CBDM prediction methods and metrics

Targeted gene disruption coupled with metabolic screen approach to uncover the LEAFY COTYLEDON1-LIKE4 (L1L4) function in tomato fruit metabolism

Key message Functional analysis of tomato L1L4 master transcription factor resulted in important metabolic changes affecting tomato fruit quality. Abstract Tomato fruits from mutant lines bearing targeted disruption of the heterotrimeric nuclear transcription factor Y (NF-Y) transcription factor (TF) gene LEAFY-COTYLEDON1-LIKE4 (L1L4, NF-YB6), a master regulator of biosynthesis for seed storage proteins and fatty acids, were evaluated for metabolites content and morphology. Metabolic screens using LC-MS/MS-based analysis and physico-chemical methods in different L1L4 mutants of the fourth generation allowed a comparative assessment of the effects of the TF disruption. Mutagenesis resulted in fruits phenotypically similar to wild-type with subtle shape differences in the distal end protrusion and symmetry. Conversely, mutant fruits from independent lines had significant variation in moisture content, titratable acidity and overall metabolite profiles including oxalic and citric acid, fructose, beta-carotene, total polyphenols and antioxidants. Lines 6, 7 and 9 were the richest in beta-carotene and antioxidant activity, line 4 in ascorbic acid and lines 4 and 8 in succinic acid. The reduced content of the anti-nutrient oxalic acid in several mutant fruits suggests that L1L4 gene may regulate the accumulation of this compound during fruit development. Detailed LC-MS/MS analysis of mutant seeds showed substantial differences in bioactive compounds compared to wild-type seeds. Taken together, the results suggest that the L1L4 TF is a significant regulator of metabolites both in tomato fruit and seeds providing a molecular target for crop improvement. Elucidation of the candidate genes encoding key enzymes in the affected metabolic pathways aimed to facilitate the L1L4 gene network exploration and eventually lead to systems biology approaches in tomato fruit quality.European funded COST ACTION [FA1106

Temporal Association of Protamine 1 with the Inner Nuclear Membrane Protein Lamin B Receptor during Spermiogenesis

International audienceDuring mammalian spermiogenesis, histones are replaced by transition proteins, which are in turn replaced by protamines P1 and P2. P1 protamine contains a short arginine/serine-rich (RS) domain that is highly phosphorylated before being deposited into sperm chromatin and almost completely dephosphorylated during sperm maturation. We now demonstrate that, in elongating spermatids, this phosphorylation is required for the temporal association of P1 protamine with lamin B receptor (LBR), an inner nuclear membrane protein that also possesses a stretch of RS dipeptides at its nucleoplasmic NH(2)-terminal domain. Previous studies have shown that the cellular protein p32 also binds tightly to the unmodified RS domain of LBR. Extending those findings, we now present evidence that p32 prevents phosphorylation of LBR and furthermore that dissociation of this protein precedes P1 protamine association. Our data suggest that docking of protamine 1 to the nuclear envelope is an important intermediate step in spermiogenesis and reveal a novel role for SR protein kinases and p32

Histones H3/H4 form a tight complex with the inner nuclear membrane protein LBR and heterochromatin protein 1

We have recently shown that heterochromatin protein 1 (HP1) interacts with the nuclear envelope in an acetylation-dependent manner. Using purified components and in vitro assays, we now demonstrate that HP1 forms a quaternary complex with the inner nuclear membrane protein LBR and a sub-set of core histones. This complex involves histone H3/H4 oligomers, which mediate binding of LBR to HP1 and cross-link these two proteins that do not interact directly with each other. Consistent with previous observations, HP1 and LBR binding to core histones is strongly inhibited when H3/H4 are modified by recombinant CREB-binding protein, revealing a new mechanism for anchoring domains of under-acetylated chromatin to the inner nuclear membrane