461 research outputs found

    Central Clock Control of Drosophila Behavioral Rhythms

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    The fruit fly brain contains ~150 central clock cells that keep time through a cell-autonomous molecular clock. Here, we used genetic techniques to electrically silence different clock cell populations and monitored the effect on feeding behavior and locomotor activity. We find that the severity of the effect of neuronal silencing varies according to the cell population targeted. Our results show that central clock cells regulate feeding and locomotor activity rhythms in parallel, suggesting that circadian control of these two distinct behavioral outputs diverges in downstream circadian output cells rather than in cells of the core clock network

    GrĂŒne Gentechnik und ökologische Landwirtschaft

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    Weltweit findet sich als Rechtsnorm in allen entsprechenden Verbraucherschutzgesetzen die Vorgabe, in der ökologischen Landwirtschaft keine gentechnisch verĂ€nderten Organismen einzusetzen. Auf europĂ€ischer Ebene enthalten weder die EU-Öko-Verordnung noch die Saatgutverkehrsrichtlinien Regelungen, aufgrund derer Schutzmaßnahmen zur Verhinderung oder Vermeidung von GVO-Einkreuzungen in ökologische Kulturen vorgeschrieben werden können. Eine PrĂŒfung der neuen Freisetzungsrichtlinie ergibt aber, dass bei der Genehmigung zum Inverkehrbringen als „besondere Bedingungen fĂŒr die Verwendung und Handhabung“ eines GVO auch Maßnahmen zum Schutz vor SachschĂ€den durch GVO-Einkreuzung vorgeschrieben werden können. Als Maßnahmen zum Schutz vor SachschĂ€den werden hauptsĂ€chlich SicherheitsabstĂ€nde zwischen Feldern mit GVO-Pflanzen und ökologisch bewirtschafteten Kulturen sowie zusĂ€tzlich gentechnikfreie Gebiete diskutiert. Bei der Analyse der Datenlage zur Definition von SicherheitsabstĂ€nden treten viele LĂŒcken in der empirischen Datenbasis zu Tage, sodass sich hier dringender Forschungsbedarf abzeichnet. Es werden pragmatisch Hinweise zu SicherheitsabstĂ€nden abgeleitet. Gentechnikfreie Gebiete resp. geschlossene Anbaugebiete werden in Zusammenhang mit der Saatgutproduktion vorgeschlagen. Bisher ermöglicht nur das Zivilrecht in Deutschland einen privaten Ausgleich der Rechts- und InteressensphĂ€ren der Bio-Bauern und der Nutzer transgener Sorten. § 906 BGB lĂ€sst sich hier als zentrale Steuerungsnorm des Umweltprivatrechts heranziehen. Dessen System von Unterlassungs- und AusgleichsansprĂŒchen ist hochkomplex und wird nur schwer zu einer zufriedenstellenden Koexistenz beitragen können. Eine Lösung wĂ€re daher eine wirksame Selbstorganisation des Wirtschaftszweigs der Saatgutindustrie, die transgene Pflanzen zĂŒchtet und das Saatgut in Verkehr bringt. Sollte diese nicht möglich sein, bietet sich eine öffentlich-rechtliche Regelung an. Dazu könnten gehören: Die Einrichtung eines Anbaukatasters, die EinfĂŒhrung einer guten fachlichen Praxis des GVO-Anbaus (GfP), die Festlegung einer Instruktionspflicht auf der Saatgutverpackung sowie der Schutz der ökologischen Saatgutproduktion

    What determines women's participation in collective action? Evidence from a western Ugandan coffee cooperative

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    Women smallholders face greater constraints than men in accessing capital and commodity markets in Sub-Saharan Africa. Collective action has been promoted to remedy those disadvantages. Using survey data of 421 women members and 210 nonmembers of a coffee producer cooperative in Western Uganda, this study investigates the determinants of women's participation in cooperatives and women's intensity of participation. The results highlight the importance of access to and control over land for women to join the cooperative in the first place. Participation intensity is measured through women's participation in collective coffee marketing and share capital contributions. It is found that duration of membership, access to extension services, more equal intrahousehold power relations, and joint land ownership positively influence women's ability to commit to collective action. These findings demonstrate the embeddedness of collective action in gender relations and the positive value of women's active participation for agricultural-marketing cooperatives

    Estimates of Black Hole Spin Properties of 55 Sources

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    Studies of black hole spin and other parameters as a function of redshift provide information about the physical state and merger and accretion histories of the systems. One way that black hole spin may be estimated is through observations of extended radio sources. These sources, powered by outflows from an AGN, allow the beam power and total outflow energy to be studied. In a broad class of models, the beam power of the outflow is related to the spin of the black hole. This relationship is used to estimate black hole spins for 55 radio sources. The samples studied include 7 FRII quasars and 19 FRII radio galaxies with redshifts between 0.056 and 1.79, and 29 radio sources associated with CD galaxies with redshifts between 0.0035 and 0.291. The FRII sources studied have estimated spin values of between about 0.2 and 1; there is a range of values at a given redshift, and the values tend to increase with increasing redshift. Results obtained for FRII quasars are very similar to those obtained for FRII galaxies. A broader range of spin values are obtained for the sample of radio sources associated with CD galaxies studied. The fraction of the spin energy extracted per outflow event is estimated and ranges from about 0.03 to 0.5 for FRII sources and 0.002 to about 1 for radio sources associated with CD galaxies; the data are consistent with this fraction being independent of redshift though the uncertainties are large. The results obtained are consistent with those predicted by numerical simulations that track the merger and accretion history of AGN, supporting the idea that, for AGN with powerful large-scale outflows, beam power is directly related to black hole spin.Comment: 13 pages; to appear in MNRA

    Employment and Health Mapping Report: Evidence and Gap Map of Systematic Reviews

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    SIPHER has been exploring the policy area of inclusive economies over the past two years, with the aim of mapping and modelling relationships between inclusive economies and health outcomes. To support this work, our Evidence Synthesis Workstrand 2 has created an evidence and gap map (EGM) exploring the relationship between employment and health outcomes. The aims of the employment and health evidence and gap map within SIPHER are to: ‱ Collate evidence from recent systematic reviews reporting on the relationship between employment (including unemployment) and health at the population level. ‱ Inform SIPHER’s understanding of the pathways and causal links between characteristics of employment and health (including health inequalities) for use in modelling and decision support tool development. ‱ To highlight gaps and opportunities for future research and to provide a tool for identifying relevant research for policymakers. This report provides a brief ‘technical’ overview of the EGM, focusing on the process that was undertaken and the methods used to produce it for those interested. The full protocol can be found separately. Instructions on how to use and interpret the map are provided separately. This report does not summarise emerging findings

    Euphrasia Eye Drops in Preterm Neonates With Ocular Discharge: A Randomized Double-Blind Placebo-Controlled Trial

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    Aim: To investigate whether the early administration of Euphrasia eye dropsÂź in preterm neonates presenting with ocular discharge fosters the resolution of the ocular discharge and reduces the need for topical antibiotic therapy, as compared to placebo. Methods: We conducted a randomized double-blind placebo-controlled trial at the University Children's Hospital Bern, Switzerland. Preterm neonates with white, yellow, or green ocular discharge were included. Infants were randomly assigned (1:1) to the Euphrasia arm (Euphrasia eye dropsÂź, Weleda AG, Arlesheim) or the placebo arm (NaCl 0.9%). Euphrasia or placebo was administrated at a dose of one drop in each eye four times a day over a period of 96 h. The primary outcome was the treatment success, defined as no ocular discharge at 96 h and no use of topical antibiotic therapy during the 96-h intervention. Results: A total of 114 neonates were screened and 84 were randomized. Among neonates in the Euphrasia arm, 22 (55.0%) achieved our primary outcome compared to 21 (51.2%) in the placebo arm (p = 0.85). In the Euphrasia arm, time to resolution of reddening tended to fall within the shorter bracket of 24 to 48 h (24 (92.3%) vs. 12 (80.0%) in the placebo arm, p = 0.34) and relapse or first signs of reddening during the 96-h intervention tended to be lower [3 (7.9%) eyes vs. 8 (18.2%) eyes in the placebo arm, p = 0.17]. Tearing at 96 h tended to be lower in the Euphrasia arm [5 (12.8%) eyes in the Euphrasia arm vs. 12 (27.3%) eyes in the placebo arm, p = 0.10]. Discussion: Euphrasia did not significantly improve treatment success, defined as no ocular discharge at 96 h and no use of topical antibiotic therapy during the 96-h intervention. However, results suggest that Euphrasia may be of benefit for symptoms such as reddening and tearing, and thus improve the comfort of patients. Trial Registration: The trial is registered at the US National Institutes of Health (ClinicalTrials.gov) NCT04122300 and at the portal for human research in Switzerland SNCTP000003490. Keywords: Euphrasia drops; complementary medicine; congenital nasolacrimal duct obstruction; ocular discharge; preterm neonate

    The effect of laser remelting on the surface chemistry of Ti6al4V components fabricated by selective laser melting

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    Surface remelting/skin scanning of components is generally performed during the selective laser melting (SLM) process to improve the surface quality of a part. However, the chemical effects of surface remelting are not well understood. In this study, cuboidal parts fabricated with and without laser remelting were characterised using scanning electron microscopy (SEM), surface profilometry and X-ray photoelectron spectrophotometry (XPS). The SEM images showed a low-amplitude undulating pattern was observed on both surfaces. The surface chemistries of the surface remelted/skin scanned (SK) and non-surface remelted/non-skin scanned (NSK) samples were observed to significantly differ in their elemental composition. The thickness of the surface oxide layer of the SK surface was double that of the NSK surface. Also, the contribution of the major alloying elements, including titanium and aluminium, on the surface oxide layer varied for both NSK and SK surfaces. The surface chemistry of the NSK and SK surface was significantly different to a conventionally forged (CF) Ti6Al4V surface. The rate of decrease of oxide with depth was in the order of CF > NSK > SK. Although surface remelting is useful in rendering improved surface quality, its impact on surface chemistry should be carefully considered

    From polyps to pixels: understanding coral reef resilience to local and global change across scales

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    Abstract Context Coral reef resilience is the product of multiple interacting processes that occur across various interacting scales. This complexity presents challenges for identifying solutions to the ongoing worldwide decline of coral reef ecosystems that are threatened by both local and global human stressors. Objectives We highlight how coral reef resilience is studied at spatial, temporal, and functional scales, and explore emerging technologies that are bringing new insights to our understanding of reef resilience. We then provide a framework for integrating insights across scales by using new and existing technological and analytical tools. We also discuss the implications of scale on both the ecological processes that lead to declines of reefs, and how we study those mechanisms. Methods To illustrate, we present a case study from Kāneʻohe Bay, Hawaiʻi, USA, linking remotely sensed hyperspectral imagery to within-colony symbiont communities that show differential responses to stress. Results In doing so, we transform the scale at which we can study coral resilience from a few individuals to entire ecosystems. Conclusions Together, these perspectives guide best practices for designing management solutions that scale from individuals to ecosystems by integrating multiple levels of biological organization from cellular processes to global patterns of coral degradation and resilience
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