31 research outputs found

    Rudimentary G-Quadruplex-Based Telomere Capping In Saccharomyces Cerevisiae

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    Telomere capping conceals chromosome ends from exonucleases and checkpoints, but the full range of capping mechanisms is not well defined. Telomeres have the potential to form G-quadruplex (G4) DNA, although evidence for telomere G4 DNA function in vivo is limited. In budding yeast, capping requires the Cdc13 protein and is lost at nonpermissive temperatures in cdc13-1 mutants. Here, we use several independent G4 DNA-stabilizing treatments to suppress cdc13-1 capping defects. These include overexpression of three different G4 DNA binding proteins, loss of the G4 DNA unwinding helicase Sgs1, or treatment with small molecule G4 DNA ligands. In vitro, we show that protein-bound G4 DNA at a 3\u27 overhang inhibits 5\u27-\u3e 3\u27 resection of a paired strand by exonuclease I. These findings demonstrate that, at least in the absence of full natural capping, G4 DNA can play a positive role at telomeres in vivo

    Demonstration of surface electron rejection with interleaved germanium detectors for dark matter searches

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    The following article appeared in Applied Physics Letters 103.16 (2013): 164105 and may be found at http://scitation.aip.org/content/aip/journal/apl/100/26/10.1063/1.4729825The SuperCDMS experiment in the Soudan Underground Laboratory searches for dark matter with a 9-kg array of cryogenic germanium detectors. Symmetric sensors on opposite sides measure both charge and phonons from each particle interaction, providing excellent discrimination between electron and nuclear recoils, and between surface and interior events. Surface event rejection capabilities were tested with two 210 Pb sources producing ∌130 beta decays/hr. In ∌800 live hours, no events leaked into the 8–115 keV signal region, giving upper limit leakage fraction 1.7 × 10−5 at 90% C.L., corresponding to < 0.6 surface event background in the future 200-kg SuperCDMS SNOLAB experiment.This work is supported in part by the National Science Foundation (Grant Nos. AST-9978911, NSF-0847342, PHY-1102795,NSF-1151869, PHY-0542066, PHY-0503729, PHY-0503629, PHY-0503641, PHY-0504224, PHY-0705052,PHY-0801708, PHY-0801712, PHY-0802575, PHY-0847342, PHY-0855299, PHY-0855525, and PHY-1205898), by the Department of Energy (Contract Nos. DE-AC03-76SF00098, DE-FG02-92ER40701, DE-FG02-94ER40823,DE-FG03-90ER40569, DE-FG03-91ER40618, and DESC0004022),by NSERC Canada (Grant Nos. SAPIN 341314 and SAPPJ 386399), and by MULTIDARK CSD2009-00064 and FPA2012-34694. Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359, while SLAC is operated under Contract No. DE-AC02-76SF00515 with the United States Department of Energy

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    A field of alternative food organizations: a study of discourses, actions and goals toward food system change in Geneva, Switzerland

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    Abstract While there is an abundant literature on alternative food organizations (AFOs), this research mostly consists of studies focusing on single types of food organizations. Hence, we lack a more encompassing understanding of how different types of AFOs are connected and what their collective transformative potential is within the food regime. In this article, we analyze how AFOs build a field, bring about social change collectively, and examine toward what type of change they work. Building on original survey data, network analyses and frames analyses, we propose an innovative quantitative operationalization of strategic action fields. We show that AFOs engaged in an information exchange network are more likely to hold systemic goals such as anticapitalism and food democracy than isolated AFOs. They also use more contentious action repertoires. We argue that a field of AFOs has more transformative potential than isolated organizations because they collectively challenge the status quo.</p

    Mapping and survey of alternative food organizations in the canton of Geneva

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    This report presents the mapping of Alternative Food Organizations (AFOs) that are active in the canton of Geneva in the spring 2019. Moreover, it discusses descriptive analyses based on an organizational survey conducted among these AFOs. The report shows that AFOs include different types of organizations that are active in four sectors - namely food production, autoproduction, distribution, and consumers' advocacy. The survey shows that AFOs display a broad heterogeneity in terms of age and size, but that they share concern for environmental protection and local agriculture. AFOs represent a dynamic sector, yet they face many challenges related to their financial stability

    Alternative Food Organizations Networks in the canton of Geneva

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    This report presents the networks through which Alternative Food Organizations (AFOs) interact. It starts with a presentation of the relational data collected in the framework of an organizational survey. Then, it presents the networks constructed around information exchange, events co-organization, and participating together in political projects. We find that about a third of the AFOs analyzed here participate in information exchange networks or co-organize events. Moreover, about a quarter participate in political projects together. These descriptive findings show that the AFOs' network is small and few AFOs interact and work together on the issue of food

    Thalamic influence on slow wave slope renormalization during sleep.

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    OBJECTIVE Slow waves are thought to mediate an overall reduction in synaptic strength during sleep. The specific contribution of the thalamus to this so-called synaptic renormalization is unknown. Thalamic stroke is associated with daytime sleepiness, along with changes to sleep electroencephalography and cognition making it a unique "experiment of nature" to assess the relationship between sleep rhythms, synaptic renormalization, and daytime functions. METHODS Sleep was studied by polysomnography and high-density electroencephalography over 17 nights in patients with thalamic (n = 12) and 15 nights in patients with extra-thalamic (n = 11) stroke. Sleep electroencephalography overnight slow wave slope changes, and their relationship with subjective daytime sleepiness, cognition, and other functional tests were assessed. RESULTS Thalamic and extra-thalamic patients did not differ in terms of age, sleep duration or apnea-hypopnea index. Conversely, overnight slope changes were reduced in a large cluster of electrodes in thalamic compared to extra-thalamic stroke patients. This reduction was related to increased daytime sleepiness. No significant differences were found in other functional tests between the two groups. INTERPRETATION In patients with thalamic stroke a reduction in overnight slow wave slope change and increased daytime sleepiness was found. Sleep- and wake-centered mechanisms for this relationship are discussed. Overall, this study suggests a central role of the thalamus in synaptic renormalization. This article is protected by copyright. All rights reserved

    Closing the pneumococcal conjugate vaccine (PCV) introduction gap: an archetype analysis of last-mile countries

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    Background Pneumonia remains the leading infectious cause of global childhood deaths, despite the availability of pneumococcal conjugate vaccine (PCV) products and widespread evidence of their safety and efficacy. Objective To map the landscape of countries that are yet to fully include PCV in their National Immunization Programs, we conducted an archetype analysis of country indicators related to barriers and facilitators for PCV decision-making. Methods We created a country matrix focused on three key domains – health characteristics, immunisation factors, and policy framework, and identified ten related indicators. We scored countries based on indicator performance and subsequently ranked and grouped them into three archetypes of low-, moderate-, and high-barrier countries with regard to PCV introduction. Results Our results indicated 39 countries (33 low- and middle-income countries [LMICs] and 6 high-income countries) that are yet to introduce PCV. Among LMICs, 15 countries were classified as ‘low-barrier,’ indicating factors favourable for PCV introduction such as high immunisation coverage of common childhood vaccines, supportive governments, and substantial disease burden and eligibility for Gavi support. Countries classified in the ‘moderate-barrier’ (12) and ‘high-barrier’ (6) archetypes demonstrated adequate capacity in immunisation systems but had competing national priorities and cost barriers that impeded policy decision-making on PCV introduction. Conclusions The current health and policy indicator-based categorisation provides an actionable framework to design tailored PCV advocacy within these last-mile countries. Policy approaches emerging from this framework can lead to strengthened decision-making on vaccine introduction and sustained vaccine access that can enhance child survival worldwide

    Introduction of the pneumococcal conjugate vaccine in humanitarian and fragile contexts: Perspectives from stakeholders in four African countries

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    ABSTRACTChildhood pneumonia causes a significant burden of preventable child morbidity and mortality in Chad, Guinea, Somalia/Somaliland, and South Sudan. Leaders from these countries have committed to reducing this burden and are preparing to introduce the pneumococcal conjugate vaccine (PCV) into their immunization programs. To support long-term sustainability for expected PCV introductions in settings afflicted by prolonged humanitarian crises this research explores national stakeholders’ perspectives on contextual factors that may influence optimal vaccine implementation. This qualitative study used purposive sampling to identify and interview stakeholders involved in vaccine decision-making. Interview transcripts were analyzed through the framework method, an approach involving charting data into pre-populated matrices. Findings from interviews with 16 key informants from government, partner organizations, and international health agencies fit within the following four overarching themes: (1) population-level vulnerabilities to pneumonia, exacerbated by climatic risks and low levels of maternal education; (2) disease burden and the interest in enhancing surveillance to monitor vaccine impact and integrate disease control efforts; (3) policy processes, including formalizing vaccine decision-making; and (4) vaccine implementation preparation, including the conduct of robust communication campaigns, training, and cold chain upgrades. This research explores perspectives from leaders in these countries which are at pivotal moments in their journeys toward introducing PCV. Widespread commitment among leaders, in addition to financial support, will facilitate vaccine introduction. Further, fostering a shared understanding among partners about context-specific determinants of program success will help build tailored implementation strategies for each country
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