6,377 research outputs found
The CMS Electromagnetic Calorimeter at the LHC
The CMS detector at the LHC is in the final stages of preparation. The high
resolution Electromagnetic Calorimeter, which consists of nearly 76000 lead
tungstate crystals, will play a crucial role in the coming physics searches
undertaken by CMS. The design, status, and initial performance of the
calorimeter, in test beams and with cosmic rays, will be reviewed.Comment: ICHEP0
Facile syntheses of building blocks for the construction of phosphotyrosine mimetics
The copper-catalysed zinc phosphonate chemistry described by Yokomatsu and Shibuya can be used to enter the classical organometallic coupling repertoire via Stille and SuzukiāMiyaura couplings. 1,4-Diiodobenzene underwent coupling with the organozinc reagent derived from diethyl bromodifluoromethylphosphonate with copper(I) catalysis to afford diethyl (4-iodophenyl)difluoromethylphosphonate. Higher yielding couplings were run with (4-trifluoromethylsulfonyloxy)- and (4-nonafluorobutylsulfonyloxy)-iodobenzenes. The iodide and the triflate coupled under palladium-catalysed conditions with a range of stannanes and boronic acids in moderate to excellent yields. ShibuyaāYokomatsu couplings were also successful with more functionalised iodoarenes and heteroarenes presenting the important phosphate mimic on a range of scaffolds
Teachers observing classroom communication: An application of the Communicating Supporting Classroom Observation Tool for children aged 4-7 years
The nature of āTeacher talkā is likely to have a considerable bearing on the childās learning but measuring the communication environment in the classroom can present challenges. One tool which does this is the Communication Supporting Classroom Observation Tool (CSCOT). Initial use suggested that it was valid and reliably used by specialists (psychologists and speech and language therapists) and special educational needs coordinators (SENCOs). A key question is whether it can be used routinely by classroom teachers and whether results coincide with those in earlier studies. CSCOT observations were carried out by teachers in 33 schools (32 Reception classrooms, 25 in Year 1 and 25 in Year 2) in two local authorities in the North East of England and teachers were asked afterwards to reflect on their experiences using the tool. Scores were in line with those in earlier studies and were consistently higher on all dimensions for reception compared to Year 2, but there was no difference between other year groups. Results were mostly consistent with the original studies. Language learning environment was higher relative to both language learning opportunities and interactions across all years (which again did not differ). There was a moderate interaction between language learning environment where scores were significantly higher in the Reception group and lower in the Year 2 group. Teachers supported the use of the CSCOT in their feedback, suggesting that CSCOT was easy to use and useful in informing practice. The CSCOT clearly has utility as a starting point in auditing classroom communication. It allows teachers to compare between classrooms and year groups and potentially fosters collaboration between teachers and specialist practitioners who focus on communication such as speech and language therapists. Further work could link the observation tool into an intervention program co-constructed with teachers
Evaluating the regional potential for emissions reduction using energy storage
Energy storage is an enabler of low carbon electricity generation, however several studies have shown that its use can cause a non-trivial increase in carbon emissions even if the storage has 100% round-trip efficiency. To understand the impact of storage operation and demand response on emissions, it is necessary to determine the marginal emissions factor (MEF) at the time the storage or demand response was operated. This paper presents statistical approaches to determining regional MEFs using data on regional electricity demand and generation by fuel type, with a simple power flow model used to determine consumption emissions by region. The technique is applied to the electricity system in Great Britain in 2018. It is found that the impact of storage varies widely by location and operating mode, with the greatest emissions reductions achieved when storage is used to reduce wind curtailment in areas which consume high levels of fossil fuel generation, and the greatest emissions increases occurring where storage is used for wind balancing in areas where wind is not curtailed. The difference between the highest emissions reduction and highest emissions increase is found to be significant, at 785 gCO2 per kWh that passes through storage
Transcription-dependent silencing of inducible convergent transgenes in transgenic mice.
BACKGROUND: Silencing of transgenes in mice is a common phenomenon typically associated with short multi-copy transgenes. We have investigated the regulation of the highly inducible human granulocyte-macrophage colony-stimulating-factor gene (Csf2) in transgenic mice. RESULTS: In the absence of any previous history of transcriptional activation, this transgene was expressed in T lineage cells at the correct inducible level in all lines of mice tested. In contrast, the transgene was silenced in a specific subset of lines in T cells that had encountered a previous episode of activation. Transgene silencing appeared to be both transcription-dependent and mediated by epigenetic mechanisms. Silencing was accompanied by loss of DNase I hypersensitive sites and inability to recruit RNA polymerase II upon stimulation. This pattern of silencing was reflected by increased methylation and decreased acetylation of histone H3 K9 in the transgene. We found that silenced lines were specifically associated with a single pair of tail-to-tail inverted repeated copies of the transgene embedded within a multi-copy array. CONCLUSIONS: Our study suggests that epigenetic transgene silencing can result from convergent transcription of inverted repeats which can lead to silencing of an entire multi-copy transgene array. This mechanism may account for a significant proportion of the reported cases of transgene inactivation in mice.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Using electricity storage to reduce greenhouse gas emissions
While energy storage is key to increasing the penetration of variable renewables, the near-term effects of storage on greenhouse gas emissions are uncertain. Several studies have shown that storage operation can increase emissions even if the storage has 100% turnaround efficiency. Furthermore, previous studies have relied on national-level data and given very little attention to the impacts of storage on emissions at local scales. This is an important omission, as carbon intensities can vary very significantly at sub-national scales. We introduce a novel approach to calculating regional marginal emissions factors, based on a validated power system model and regression analysis. The techniques are used to investigate the impacts of storage operation on CO2 emissions in Great Britain in 2019, under a range of operating scenarios. It is found that there are significant regional differences in storage emissions factors, with storage tending to increase emissions when used for wind balancing in areas with little wind curtailment. In contrast, the greatest emissions reductions are achieved when charging storage with otherwise-curtailed renewables and discharging to reduce peak demands in areas consuming high volumes of fossil fuel power. Over all regions and operating modes studied, the difference between the highest reduction in emissions and the highest increase in emissions is considerable, at 741 gCO2 per kWh discharged. We conclude that power system regulators should pay increased attention to the impact of storage operation on system CO2 emissions.</p
Using electricity storage to reduce greenhouse gas emissions
While energy storage is key to increasing the penetration of variable renewables, the near-term effects of storage on greenhouse gas emissions are uncertain. Several studies have shown that storage operation can increase emissions even if the storage has 100% turnaround efficiency. Furthermore, previous studies have relied on national-level data and given very little attention to the impacts of storage on emissions at local scales. This is an important omission, as carbon intensities can vary very significantly at sub-national scales. We introduce a novel approach to calculating regional marginal emissions factors, based on a validated power system model and regression analysis. The techniques are used to investigate the impacts of storage operation on CO2 emissions in Great Britain in 2019, under a range of operating scenarios. It is found that there are significant regional differences in storage emissions factors, with storage tending to increase emissions when used for wind balancing in areas with little wind curtailment. In contrast, the greatest emissions reductions are achieved when charging storage with otherwise-curtailed renewables and discharging to reduce peak demands in areas consuming high volumes of fossil fuel power. Over all regions and operating modes studied, the difference between the highest reduction in emissions and the highest increase in emissions is considerable, at 741 gCO2 per kWh discharged. We conclude that power system regulators should pay increased attention to the impact of storage operation on system CO2 emissions.</p
Biobanking in the emergency department: implementation of the Mayo Clinic Emergency Department Sepsis Biorepository
Runx1 binds as a dimeric complex to overlapping Runx1 sites within a palindromic element in the human GM-CSF enhancer
Runx1 is a developmentally regulated transcription factor that is essential for haemopoiesis. Runx1 can bind as a monomer to the core consensus sequence TGTGG, but binds more efficiently as a hetero-dimer together with the non-DNA binding protein CBFĪ² as a complex termed core binding factor (CBF). Here, we demonstrated that CBF can also assemble as a dimeric complex on two overlapping Runx1 sites within the palindromic sequence TGTGGCTGCCCACA in the human granulocyte macrophage colony-stimulating factor enhancer. Furthermore, we demonstrated that binding of Runx1 to the enhancer is rigidly controlled at the level of chromatin accessibility, and is dependent upon prior induction of NFAT and AP-1, which disrupt a positioned nucleosome in this region. We employed in vivo footprinting to demonstrate that, upon activation of the enhancer, both sites are efficiently occupied. In vitro binding assays confirmed that two CBF complexes can bind this site simultaneously, and transfection assays demonstrated that both sites contribute significantly to enhancer function. Computer modelling based on the Runx1/CBFĪ²/DNA crystal structure further revealed that two molecules of CBF could potentially bind to this class of palindromic sequence as a dimeric complex in a conformation whereby both Runx1 and CBFĪ² within the two CBF complexes are closely aligned
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