78 research outputs found
Censorship, Free Speech & Facebook: Applying the First Amendment to Social Media Platforms via the Public Function Exception
Society has a love-hate relationship with social media. Thanks to social media platforms, the world is more connected than ever before. But with the ever-growing dominance of social media there have come a mass of challenges. What is okay to post? What isn\u27t? And who or what should be regulating those standards? Platforms are now constantly criticized for their content regulation policies, sometimes because they are viewed as too harsh and other times because they are characterized as too lax. And naturally, the First Amendment quickly enters the conversation. Should social media platforms be subject to the First Amendment? Can—or should—users be able to assert their First Amendment rights against these platforms? This article dives into the legal and policy implications surrounding the application of the First Amendment to social media platforms. Because the state action doctrine generally serves as a bar to enforcing constitutional restrictions on private actors, this Article examines these First Amendment questions in light of the state action doctrine, and more particularly its public function exception. This Article considers whether social media platforms fit within the public function exception and whether such an applicable is tenable and proper as a matter of law and public policy
High-gradient plasma and laser accelerators
Novel high-gradient accelerators have demonstrated acceleration of electrons and positrons with electric field strengths of 1 to > 100 GeV/m. This is about 10 to 1000 times higher than achieved in RF-based accelerators, and as such they have the potential to overcome the limitations associated with RF cavities. Plasma-based accelerators have produced multi-GeV bunches with parameters approaching those suitable for a linear collider. These accelerators offer the prospect of near term, compact and cost-effective particle physics experiments that provide new physics possibilities supporting precision studies and the search for new particles.
The expert panel has defined a long term R&D roadmap towards a compact collider with attractive intermediate experiments and studies. A delivery plan for the required R&D has been developed and includes work packages, deliverables, a minimal plan, connections to ongoing projects and an aspirational plan
Gene Regulation and Epigenetic Remodeling in Murine Embryonic Stem Cells by c-Myc
BACKGROUND:The Myc oncoprotein, a transcriptional regulator involved in the etiology of many different tumor types, has been demonstrated to play an important role in the functions of embryonic stem (ES) cells. Nonetheless, it is still unclear as to whether Myc has unique target and functions in ES cells. METHODOLOGY/PRINCIPAL FINDINGS:To elucidate the role of c-Myc in murine ES cells, we mapped its genomic binding sites by chromatin-immunoprecipitation combined with DNA microarrays (ChIP-chip). In addition to previously identified targets we identified genes involved in pluripotency, early development, and chromatin modification/structure that are bound and regulated by c-Myc in murine ES cells. Myc also binds and regulates loci previously identified as Polycomb (PcG) targets, including genes that contain bivalent chromatin domains. To determine whether c-Myc influences the epigenetic state of Myc-bound genes, we assessed the patterns of trimethylation of histone H3-K4 and H3-K27 in mES cells containing normal, increased, and reduced levels of c-Myc. Our analysis reveals widespread and surprisingly diverse changes in repressive and activating histone methylation marks both proximal and distal to Myc binding sites. Furthermore, analysis of bulk chromatin from phenotypically normal c-myc null E7 embryos demonstrates a 70-80% decrease in H3-K4me3, with little change in H3-K27me3, compared to wild-type embryos indicating that Myc is required to maintain normal levels of histone methylation. CONCLUSIONS/SIGNIFICANCE:We show that Myc induces widespread and diverse changes in histone methylation in ES cells. We postulate that these changes are indirect effects of Myc mediated by its regulation of target genes involved in chromatin remodeling. We further show that a subset of PcG-bound genes with bivalent histone methylation patterns are bound and regulated in response to altered c-Myc levels. Our data indicate that in mES cells c-Myc binds, regulates, and influences the histone modification patterns of genes involved in chromatin remodeling, pluripotency, and differentiation
A communal catalogue reveals Earth's multiscale microbial diversity
Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe
A communal catalogue reveals Earth’s multiscale microbial diversity
Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Bridging from cells to cognition in autism pathophysiology: biological pathways to defective brain function and plasticity
Abstract: We review evidence to support a model where the disease process underlying autism may begin when an in utero or early postnatal environmental, infectious, seizure, or autoimmune insult triggers an immune response that increases reactive oxygen species (ROS) production in the brain that leads to DNA damage (nuclear and mitochondrial) and metabolic enzyme blockade and that these inflammatory and oxidative stressors persist beyond early development (with potential further exacerbations), producing ongoing functional consequences. In organs with a high metabolic demand such as the central nervous system, the continued use of mitochondria with damaged DNA and impaired metabolic enzyme function may generate additional ROS which will cause persistent activation of the innate immune system leading to more ROS production. Such a mechanism would self-sustain and possibly progressively worsen. The mitochondrial dysfunction and altered redox signal transduction pathways found in autism would conspire to activate both astroglia and microglia. These activated cells can then initiate a broad-spectrum proinflammatory gene response. Beyond the direct effects of ROS on neuronal function, receptors on neurons that bind the inflammatory mediators may serve to inhibit neuronal signaling to protect them from excitotoxic damage during various pathologic insults (e.g., infection). In autism, over-zealous neuroinflammatory responses could not only influenc
Bright quasi-phase-matched soft-x-ray harmonic radiation from argon ions
Selective enhancement (>10^3) of harmonics extending to the water window
(~4nm) generated in an argon gas filled straight bore capillary waveguide is
demonstrated. This enhancement is in good agreement with modeling which
indicates that multimode quasi-phasematching (MMQPM) is achieved by rapid axial
intensity modulations caused by beating between the fundamental and higher
order capillary modes. Substantial pulse-energies (>10nJ per pulse per harmonic
order) at wavelengths beyond the carbon K-edge (~4.37nm, ~284eV) up to ~360eV
are observed from argon ions for the first time.Comment: 13 pages including 4 figure
Bridging from Cells to Cognition in Autism Pathophysiology: Biological Pathways to Defective Brain Function and Plasticity
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