326 research outputs found
Metagenomic Analysis of Microbial 18s Eukaryotes Communities and Environmental factors in the Western Antarctic Peninsula waters during Austral Summers
Little is known about the environmental factors that impact eukaryotic microbial populations in the Western Antarctic Peninsula. Metagenomic and environmental data have been collected over the course of three consecutive austral summers in the Western Antarctic Peninsula off Palmer Station. More than 13 million 18S rRNA eukaryotic sequences have been taxonomically identified and categorized from the Antarctic water samples collected. Here we will investigate the environmental factors that affect eukaryotic organism populations, as well as possible indicator species that could provide insight as to the status of other eukaryotic species. Due to climate change, understanding these factors and identifying status indicating species is becoming increasingly important in understanding microbial systems, and to inform future research of Antarctic ecosystems and environmental conditions. We identified several groupings of correlated taxonomic operational units. Additionally, we found that Stramenopiles.Diatomea.ME-Euk-FW10, an uncultured diatom with a large population presence, had a particularly strong correlation to temperature
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Separating Law-Making from Sausage-Making: The Case for Judicial Review of the Legislative Process
Inspired, perhaps, by the old adage that "people who like sausages and respect the law should never watch either being made," there is significant resistance among judges and scholars alike to the idea that courts should review the lawmaking process. This doctoral dissertation challenges this prevalent position, and establishes the case for judicial review of the legislative process. The dissertation develops the arguments for the authority of courts to review the legislative process; the legitimacy and theoretical justifications of such judicial review; and the practical and normative importance of such judicial involvement. It also challenges the resistance to judicial review of the legislative process by scrutinizing, and seeking to rebut, the major arguments underlying this resistance, and revealing this position's doctrinal and theoretical incoherence, and its negative consequences. In an effort to provide a multifaceted exploration of the issue, the dissertation combines multiple approaches of legal scholarship, including a legal-doctrinal approach, a comparative law approach, a jurisprudential and constitutional theory approach, and an interdisciplinary approach that draws upon political science research and several other disciplines
Lawmakers as Lawbreakers
How would Congress act in a world without judicial review? Canlawmakers be trusted to police themselves? This Article examinesCongress’s capacity and incentives to enforce upon itself “the law ofcongressional lawmaking”—a largely overlooked body of law that iscompletely insulated from judicial enforcement. The Article exploresthe political safeguards that may motivate lawmakers to engage inself-policing and rule-following behavior. It identifies the majorpolitical safeguards that can be garnered from the relevant legal,political science, political economy, and social psychology scholarship,and evaluates each safeguard by drawing on a combination oftheoretical, empirical, and descriptive studies about Congress. TheArticle’s main argument is that the political safeguards that scholarsand judges commonly rely upon to constrain legislative behavioractually motivate lawmakers to be lawbreakers.
In addition to providing insights about Congress’s behavior in theabsence of judicial review, this Article’s examination contributes tothe debate about judicial review of the legislative process, the generaldebate on whether political safeguards reduce the need for judicialreview, and the burgeoning new scholarship about legislative rules
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Three-dimensional computational fluid dynamics for the Spallation Neutron Source liquid mercury target
The Spallation Neutron Source (SNS) is a high-power accelerator-based pulsed spallation source being designed by a multilaboratory team led by Oak Ridge National Laboratory (ORNL) to achieve high fluxes of neutrons for scientific experiments. Computational fluid dynamics (CFD) is being used to analyze the SNS design. The liquid-mercury target is subjected to the neutronic (internal) heat generation that results from the proton collisions with the mercury nuclei. The liquid mercury simultaneously serves as the neutronic target medium, transports away the heat generated within itself, and cools the metallic target structure. Recirculation and stagnation zones within the target are of particular concern because of the likelihood that they will result in local hot spots. These zones exist because the most feasible target designs include a complete U-turn flow redirection. Although the primary concern is that the target is adequately cooled, the pressure drop from inlet to outlet must also be considered because pressure drop directly affects structural loading and required pumping power. Based on the current design, a three-dimensional CFD model has been developed that includes the stainless steel target structure, the liquid-mercury target flow, and the liquid-mercury cooling jacket that wraps around the nose of the target
A New Nuclear Function of the Entamoeba histolytica Glycolytic Enzyme Enolase: The Metabolic Regulation of Cytosine-5 Methyltransferase 2 (Dnmt2) Activity
Cytosine-5 methyltransferases of the Dnmt2 family function as DNA and tRNA methyltransferases. Insight into the role and biological significance of Dnmt2 is greatly hampered by a lack of knowledge about its protein interactions. In this report, we address the subject of protein interaction by identifying enolase through a yeast two-hybrid screen as a Dnmt2-binding protein. Enolase, which is known to catalyze the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), was shown to have both a cytoplasmatic and a nuclear localization in the parasite Entamoeba histolytica. We discovered that enolase acts as a Dnmt2 inhibitor. This unexpected inhibitory activity was antagonized by 2-PG, which suggests that glucose metabolism controls the non-glycolytic function of enolase. Interestingly, glucose starvation drives enolase to accumulate within the nucleus, which in turn leads to the formation of additional enolase-E.histolytica DNMT2 homolog (Ehmeth) complex, and to a significant reduction of the tRNAAsp methylation in the parasite. The crucial role of enolase as a Dnmt2 inhibitor was also demonstrated in E.histolytica expressing a nuclear localization signal (NLS)-fused-enolase. These results establish enolase as the first Dnmt2 interacting protein, and highlight an unexpected role of a glycolytic enzyme in the modulation of Dnmt2 activity
Expression of bovine leukemia virus ENV glycoprotein in insect cells by recombinant baculovirus
AbstractThe gp51-p30 glycoprotein constituting BLV envelope was expressed in Sf-21 insect cells by means of recombinant baculoviruses. Post-infection cell lysates were analyzed, in order to define the immunologic reactivity of recombinant products. Oligosaccharide chains, containing N-acetylglucosamine, mannose, galactose and sialic acid were found on recombinant gp51-p30. In order to investigate the timing of transcription and translation of the glycoprotein, kinetic assays were carried out on cell lysates and directly in situ on Sf-21 cells during the course of baculovirus infection. The use of different solubilizing reagents was also evaluated in order to rescue recombinant glycoprotein from its subcellular location
Hydrothermal formation of fibrous mineral structures: The role on strength and mode of failure
Studying the mechanisms that control the rheology of rocks and geomaterials is crucial as much for predicting geological processes as for functionalizing geomaterials. That requires the understanding of how structural arrangements at the micro and nano scale control the physical and mechanical properties at the macroscopic scale. This is an area of rock physics still in its infancy. In this paper, we focus the attention on the formation of cementitious phases made of micro- and nano-scale fibrous structures, and the controls of the arrangement of these phases on mechanical properties. We use hydrothermal synthesis, and the properties of hydrothermal water, to promote the growth of fibrous mineral phases having nano-size diameter and length of a few microns, creating disordered and entangled mats of fibrous bundles as those found in natural samples. We draw inferences from structural microscopy to inform a statistical model that establishes an interdependence between structural parameters of fibrous structures and bulk mechanical response. Structural parameters include number and length of fibers, spatial orientation, and fraction of fibrous threads bearing the load. Mechanical properties include strength and mode of failure. Results show that as the fibrous microstructure evolves from ordered and aligned to disordered and entangled, the mechanical response of the fibrous composite transitions from a brittle to ductile behavior. Furthermore, the disordered and entangled microstructure exhibits lower strength at failure though strength increases as the number of fibers within the microstructure increases. Finally, the longer the entangled fiber, the larger the strain that the matrix can accommodate. The value of this study lies in further understanding fault healing through hydrothermal fluids and how the physical properties of fibrous microstructures resulting from it control brittle-ductile transitions, and possibly, slow slip events along subduction zones
An innovative tool to assess the functional resilience of a school system: learning from the COVID-19 pandemic
IntroductionPreparing the school system for a future crisis requires the ability to examine the effectiveness of schools’ functioning during distant learning and their level of preparedness for future crises. Functional resilience (FR) is defined as the ability to maintain vital operational continuity in the face of disturbance. The study objectives included to develop a FR index of schools and to evaluate and validate it.MethodsTo enable examination of the study objectives, the study design included tool development, followed by a validation process among 20 content experts. Concurrently, an eDelphi process for building an inclusive index, based on various components of resilience was conducted. The final study tool consists of four tailored questionnaires to examine perceptions of key stakeholders, i.e.- teachers, principals, parents, and highschool students regarding communication, psychosocial aspects, perceived stress, infrastructure, resources, pedagogic support, digital literacy, and perceived FR. Using an internet panel, the tool was disseminated cross-sectionally among the four groups of stakeholders.ResultsThe results showed high reliability of most of the scales developed. Furthermore, a high consensus level was reached on the relative importance of each component/ stakeholder to the schools FR. The findings further suggest that there were no significant differences in the composite FR score based on characteristics such as school type/ size/geographic location. However, the findings revealed interesting variations among stakeholders, with findings suggesting greater vulnerability among some.DiscussionTo increase resilience and preparedness for future adversities that school systems may face, it is recommended to periodically incorporate an assessment based on a structured tool
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Thermal-hydraulic analysis of the liquid mercury target for the national spallation neutron source
The National Spallation Neutron Source (NSNS) is a high-energy, accelerator-based spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory (ORNL) to achieve very high fluxes of neutrons for scientific experiments. The NSNS is proposed to have a 1 MW beam of high-energy ({approximately}1 GeV) protons upgradable to 5 MW and operating at 60 Hz with a pulse duration of 0.5 {mu}s. Peak steady-state power density in the target is about 640 MW/m{sup 3} for 1 MW, whereas the pulse instantaneous peak power density is as high as 22,000 GW/m{sup 3}. The local peak temperature rise for a single pulse over it`s time-averaged value is only 6{degrees}C, but the rate of this temperature rise during the pulse is extremely fast ({approximately}12 million {degrees}C/s). In addition to the resulting thermal shock and materials compatibility concerns, key feasibility issues for the target are related to its thermal-hydraulic performance. These include proper flow distribution, flow reversals and stagnation zones, possible {open_quotes}hot spots{close_quotes}, cooling of the beam {open_quotes}window{close_quotes}, and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles. An analytic approach was used on the PC spreadsheet EXCEL to evaluate target design options and to determine the global T/H parameters in the current concept. The general computational fluid dynamics (CFD) code CFX was used to simulate the detailed time-averaged two-dimensional thermal and flow distributions in the liquid mercury. In this paper, an overview of the project and the results of this preliminary work are presented. Heat transfer characteristics of liquid mercury under wetting and non-wetting conditions are discussed, and future directions of the program in T/H analysis and R&D are outlined
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