903 research outputs found
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Co-expression Networks From Gene Expression Variability Between Genetically Identical Seedlings Can Reveal Novel Regulatory Relationships.
Co-expression networks are a powerful tool to understand gene regulation. They have been used to identify new regulation and function of genes involved in plant development and their response to the environment. Up to now, co-expression networks have been inferred using transcriptomes generated on plants experiencing genetic or environmental perturbation, or from expression time series. We propose a new approach by showing that co-expression networks can be constructed in the absence of genetic and environmental perturbation, for plants at the same developmental stage. For this, we used transcriptomes that were generated from genetically identical individual plants that were grown under the same conditions and for the same amount of time. Twelve time points were used to cover the 24-h light/dark cycle. We used variability in gene expression between individual plants of the same time point to infer a co-expression network. We show that this network is biologically relevant and use it to suggest new gene functions and to identify new targets for the transcriptional regulators GI, PIF4, and PRR5. Moreover, we find different co-regulation in this network based on changes in expression between individual plants, compared to the usual approach requiring environmental perturbation. Our work shows that gene co-expression networks can be identified using variability in gene expression between individual plants, without the need for genetic or environmental perturbations. It will allow further exploration of gene regulation in contexts with subtle differences between plants, which could be closer to what individual plants in a population might face in the wild
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Addendum to Guarantee Testing Results from the Greenidge Multi-Pollutant Control Project: Additiona NH3, NOx, and CO Testing Results
On March 28-30 and May 1-4, 2007, CONSOL Energy Inc. Research & Development (CONSOL R&D) performed flue gas sampling at AES Greenidge to verify the performance of the multi-pollutant control system recently installed by Babcock Power Environmental Inc. (BPEI) on the 107-MW Unit 4 (Boiler 6). The multi-pollutant control system includes combustion modifications and a hybrid selective non-catalytic reduction (SNCR)/in-duct selective catalytic reduction (SCR) system to reduce NO{sub x} emissions, followed by a Turbosorp{reg_sign} circulating fluidized bed dry scrubber system and baghouse to reduce emissions of SO{sub 2}, SO{sub 3}, HCl, HF, and particulate matter. Mercury removal is provided via the co-benefits afforded by the in-duct SCR, dry scrubber, and baghouse and by injection of activated carbon upstream of the scrubber, as required. The testing in March and May demonstrated that the multi-pollutant control system attained its performance targets for NO{sub x} emissions, SO{sub 2} removal efficiency, acid gas (SO{sub 3}, HCl, and HF) removal efficiency, and mercury removal efficiency. However, the ammonia slip measured between the SCR outlet and air heater inlet was consistently greater than the guarantee of 2 ppmvd {at} 3% O{sub 2}. As a result, additional testing was performed on May 30-June 1 and on June 20-21, 2007, in conjunction with tuning of the hybrid NO{sub x} control system by BPEI, in an effort to achieve the performance target for ammonia slip. This additional testing occurred after the installation of a large particle ash (LPA) screen and removal system just above the SCR reactor and a fresh SCR catalyst layer in mid-May. This report describes the results of the additional tests. During the May 30-June 1 sampling period, CONSOL R&D and Clean Air Engineering (CAE) each measured flue gas ammonia concentrations at the air heater inlet, downstream of the in-duct SCR reactor. In addition, CONSOL R&D measured flue gas ammonia concentrations at the economizer outlet, upstream of the SCR reactor, and CAE measured flue gas NO{sub x} and CO concentrations at the sampling grids located at the inlet and outlet of the SCR reactor. During the June 20-21 sampling period, CONSOL R&D measured flue gas ammonia concentrations at the air heater inlet. All ammonia measurements were performed using a modified version of U.S. Environmental Protection Agency (EPA) Conditional Test Method (CTM) 027. The NO{sub x} and CO measurements were performed using U.S. EPA Methods 7E and 10, respectively
Recommended from our members
Guarantee Testing Results from the Greenidge Mult-Pollutant Control Project
CONSOL Energy Inc. Research & Development (CONSOL R&D) performed flue gas sampling at AES Greenidge to verify the performance of the multi-pollutant control system recently installed by Babcock Power Environmental Inc. (BPEI) on the 107-megawatt (MW) Unit 4 (Boiler 6). The multi-pollutant control system includes combustion modifications and a hybrid selective non-catalytic reduction (SNCR)/induct selective catalytic reduction (SCR) system to reduce NO{sub x} emissions, followed by a Turbosorp{reg_sign} circulating fluidized bed dry scrubber system and baghouse to reduce emissions of SO{sub 2}, SO{sub 3}, HCl, HF, and particulate matter. Mercury removal is provided via the co-benefits afforded by the in-duct SCR, dry scrubber, and baghouse and by injection of activated carbon upstream of the scrubber, as required. Testing was conducted through ports located at the inlet and outlet of the SCR reactor to evaluate the performance of the hybrid NO{sub x} control system, as well as through ports located at the air heater outlet and baghouse outlet or stack to determine pollutant removal efficiencies across the Turbosorp{reg_sign} scrubber and baghouse. Data from the unit's stack continuous emission monitor (CEM) were also used for determining attainment of the performance targets for NO{sub x} emissions and SO{sub 2} removal efficiency
ELF3 controls thermoresponsive growth in Arabidopsis
Plant development is highly responsive to ambient temperature, and this trait has been linked to the ability of plants to adapt to climate change [1]. The mechanisms by which natural populations modulate their thermoresponsiveness are not known [2]. To address this, we surveyed Arabidopsis accessions for variation in thermal responsiveness of elongation growth and mapped the corresponding loci. We find that the transcriptional regulator EARLY FLOWERING3 (ELF3) controls elongation growth in response to temperature. Through a combination of modeling and experiments, we show that high temperature relieves the gating of growth at night, highlighting the importance of temperature-dependent repressors of growth. ELF3 gating of transcriptional targets responds rapidly and reversibly to changes in temperature. We show that the binding of ELF3 to target promoters is temperature dependent, suggesting a mechanism where temperature directly controls ELF3 activity
Evaluating the Medical Kit System for the International Space Station(ISS) - A Paradigm Revisited
Medical capabilities aboard the International Space Station (ISS) have been packaged to help astronaut crew medical officers (CMO) mitigate both urgent and non-urgent medical issues during their 6-month expeditions. Two ISS crewmembers are designated as CMOs for each 3-crewmember mission and are typically not physicians. In addition, the ISS may have communication gaps of up to 45 minutes during each orbit, necessitating medical equipment that can be reliably operated autonomously during flight. The retirement of the space shuttle combined with ten years of manned ISS expeditions led the Space Medicine Division at the NASA Johnson Space Center to reassess the current ISS Medical Kit System. This reassessment led to the system being streamlined to meet future logistical considerations with current Russian space vehicles and future NASA/commercial space vehicle systems. Methods The JSC Space Medicine Division coordinated the development of requirements, fabrication of prototypes, and conducted usability testing for the new ISS Medical Kit System in concert with implementing updated versions of the ISS Medical Check List and associated in-flight software applications. The teams constructed a medical kit system with the flexibility for use on the ISS, and resupply on the Russian Progress space vehicle and future NASA/commercial space vehicles. Results Prototype systems were developed, reviewed, and tested for implementation. Completion of Preliminary and Critical Design Reviews resulted in a streamlined ISS Medical Kit System that is being used for training by ISS crews starting with Expedition 27 (June 2011). Conclusions The team will present the process for designing, developing, , implementing, and training with this new ISS Medical Kit System
Tunable phenotypic variability through an autoregulatory alternative sigma factor circuit.
Genetically identical individuals in bacterial populations can display significant phenotypic variability. This variability can be functional, for example by allowing a fraction of stress prepared cells to survive an otherwise lethal stress. The optimal fraction of stress prepared cells depends on environmental conditions. However, how bacterial populations modulate their level of phenotypic variability remains unclear. Here we show that the alternative sigma factor σV circuit in Bacillus subtilis generates functional phenotypic variability that can be tuned by stress level, environmental history and genetic perturbations. Using single-cell time-lapse microscopy and microfluidics, we find the fraction of cells that immediately activate σV under lysozyme stress depends on stress level and on a transcriptional memory of previous stress. Iteration between model and experiment reveals that this tunability can be explained by the autoregulatory feedback structure of the sigV operon. As predicted by the model, genetic perturbations to the operon also modulate the response variability. The conserved sigma-anti-sigma autoregulation motif is thus a simple mechanism for bacterial populations to modulate their heterogeneity based on their environment
Better Workers, Better Elections? Electoral Management Body Workforces and Electoral Integrity Worldwide
Building better elections is a central task for the study of democracy and democratisation. Despite this, there have been no cross-national studies on the staff who manage and implement elections: electoral management body (EMB) workforces. This article provides the first macroscopic worldwide picture of workforce characteristics, human resource management practices and employee outcomes, and analyses the effects they have on electoral integrity, based on original international surveys of electoral management bodies (EMBs) (n = 51) and electoral officials (n = 2029). Drawing from the human resource management literature, a framework is developed to explain how these factors might interact with EMB performance. Analysis demonstrates them to be highly related. Adding data on human resource management practices and employee outcomes improves explanatory models designed to predict the performance of EMBs. Chiefly, EMBs that enable greater opportunities for employees to be involved in decision-making processes perform better. Recruitment practices, job satisfaction and levels of stress are also important
Evaluating the Medical Kit System for the International Space Station A Paradigm Revisited
This slide presentation reviews the Medical Kit for the International Space Station. It includes a review of the kit, the users, the implementation of new kits, and lessons learned
Phytochromes function as thermosensors in Arabidopsis
Plants are responsive to temperature, and can distinguish differences of 1ºC. In Arabidopsis, warmer temperature accelerates flowering and increases elongation growth hermomorphogenesis). The mechanisms of temperature perception are however largely unknown. We describe a major thermosensory role for the phytochromes (red light receptors) during the night. Phytochrome null plants display a constitutive warm temperature response, and consistent with this, we show in this background that the warm temperature transcriptome becomes de-repressed at low temperatures. We have discovered phytochrome B (phyB) directly associates with the promoters of key target genes in a temperature dependent manner. The rate of phyB inactivation is proportional to temperature in the dark, enabling phytochromes to function as thermal timers, integrating temperature information over the course of the night
The narrative self, distributed memory, and evocative objects
In this article, I outline various ways in which artifacts are interwoven with autobiographical memory systems and conceptualize what this implies for the self. I first sketch the narrative approach to the self, arguing that who we are as persons is essentially our (unfolding) life story, which, in turn, determines our present beliefs and desires, but also directs our future goals and actions. I then argue that our autobiographical memory is partly anchored in our embodied interactions with an ecology of artifacts in our environment. Lifelogs, photos, videos, journals, diaries, souvenirs, jewelry, books, works of art, and many other meaningful objects trigger and sometimes constitute emotionally-laden autobiographical memories. Autobiographical memory is thus distributed across embodied agents and various environmental structures. To defend this claim, I draw on and integrate distributed cognition theory and empirical research in human-technology interaction. Based on this, I conclude that the self is neither defined by psychological states realized by the brain nor by biological states realized by the organism, but should be seen as a distributed and relational construct
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