3,129 research outputs found

    Asymmetric hyperbolic L-spaces, Heegaard genus, and Dehn filling

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    An L-space is a rational homology 3-sphere with minimal Heegaard Floer homology. We give the first examples of hyperbolic L-spaces with no symmetries. In particular, unlike all previously known L-spaces, these manifolds are not double branched covers of links in S^3. We prove the existence of infinitely many such examples (in several distinct families) using a mix of hyperbolic geometry, Floer theory, and verified computer calculations. Of independent interest is our technique for using interval arithmetic to certify symmetry groups and non-existence of isometries of cusped hyperbolic 3-manifolds. In the process, we give examples of 1-cusped hyperbolic 3-manifolds of Heegaard genus 3 with two distinct lens space fillings. These are the first examples where multiple Dehn fillings drop the Heegaard genus by more than one, which answers a question of Gordon.Comment: 19 pages, 2 figures. v2: minor changes to intro. v3: accepted version, to appear in Math. Res. Letter

    Research focusing on plant performance in constructed wetlands and agronomic application of treated wastewater – A set of experimental studies in Sicily (Italy)

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    Constructed wetlands are sustainable technologies for the treatment of wastewater. These biological systems have been widely studied throughout the world for more than 30 years; however, most studies have focused on the effects of design and engineering on pollutant removal from wastewater. Undoubtedly, agro-technical aspects have been given too little consideration by research. This paper reports the main results of a set of experiments carried out on two pilot horizontal subsurface flow systems in Sicily (Italy). Festuca, Lolium and Pennisetum spp. in combination and three emergent macrophytes–Arundo donax L., Cyperus alternifolius L. and Typha latifolia L.–alone, were assessed. The aim of the study was to demonstrate that, under predetermined hydraulic and design conditions, the choice of plant species and the management of the vegetation can significantly affect the pollutant removal performance of constructed wetlands. In addition, wastewater (after treatment) can also be used for agricultural purposes leading to increased sustainability in agricultural systems. Arundo and Typha-planted units performed better than Cyperus-planted units in terms of chemical, physical and microbiological contaminant removal. All the species adapted extremely well to wetland conditions. Polyculture systems were found to be more efficient than monocultures in the removal of dissolved organic compounds. The reuse of treated wastewater for the irrigation of open fields and horticultural crops led to significant savings in the use of freshwater and fertilizers. The results of physical-energy characterization of A. donax above-ground plant residues and pellets highlighted the fact that a constructed wetland could also be a potential source of bioenergy

    Multiple Wesen

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    Abstract in tedesco del Poster Multiple Wesen, esposto al Simposio internazionale „Lunar Base. Bauen fuer ein Leben auf dem Mond” tenuto a Kaiserslautern il 12-13 Maggio 2009. Was baut man auf dem Mond? Wie baut der Erdmensch auf dem Mond? WofĂĽr wird gebaut? FĂĽr wem wird gebaut? Welche Nutzungen, wie groĂź, welche Materialien? Man kann weiter fragen,... Sind dieses ĂĽberhaupt die richtige Fragen? Kann man ĂĽberhaupt vom Bauen auf dem Mond sprechen? Oder geht es darum, was der Mensch auf den Mond mit bringt, aus seiner Kenntniss, seinen Vorstellungen, seinen Träumen, seiner Erfahrung: was bringt er von dem Reich des Bekannten (der Erde) in das Reich des nur Vorstellbaren (dem Mond). Also: sich mit dem Mond zu beschäftigen - ausgenommen fĂĽr die sehr wenigen, die schon dort waren – heiĂźt, sich mit sich selbst zu beschäftigen, mit dem eigenen Wissen und dem Bild vom Mond. Alle Voraussetzungen, die einem irdischen architektonischen Entwurf zu Grunde liegen, fehlen; zu diesem Zeitpunkt kann man sich arbiträr Rahmenbedingungen geben: (Größe, wo, welche Nutzung, welche Lebensdauer, welche Materialien) so zu sagen ein Mondprojekt in einem Erdprojekt zu entwickeln, dadurch schnell eine „abgesicherte“, unangreifbare Lösung zu erlangen. Aber macht dieses Sinn? Bedeutet dies, die Spannung und die Erforschung des Neuen sowie das kreative Potential örtlicher Schwierigkeiten im Vorfeld auszuschlieĂźen? Wir schlagen vor, anstatt auf hiesige Fragen irdische Antworten zu formulieren, Strukturen zum Mond zu bringen; Raumstrukturen, die durch mentale Konzepte begrĂĽndet sind, welche die vielen Fragen - auch welche die wir jetzt nicht zu fragen gewagt haben - aufnehmen können. Diese Strukturen, aber auch kleine räumliche Gebilde, helfen dem Vorstellungsvermögen der Forscher, Ingenieure, Wissenschaftler und alle Mondinteressenten. Neutrale Strukturen, ohne jetzt genau alle physische Eigenschaften festlegen zu wollen, sollen Raum werden können fĂĽr Wohnen, Arbeiten, Forschen, Landen, Binden, SchĂĽtzen, Aufbewahren, usw. - abhängig von den Fragen, die sich zu gegebener Zeit formulieren lassen und ständig ändern werden. Wir denken an sehr flexible Strukturen, die viel aufnehmen und aushalten können, sich sehr schnell transformieren lassen, also multiple Wesen, die zunächst die Vorstellung eines belebten Mondes anregen sollen. Dieser Strukturenkatalog soll dem Wissenschaftler zur VerfĂĽgung stehen, um das Mitdenken seiner räumlichen BedĂĽrfnisse zu stĂĽtzen. Comunicato stampa Contributo degli studenti di Architettura al Simposio “Lunar Base - Costruire per una vita sulla Luna” A Kaiserslautern in Germania è in corso (12-13-maggio) il Simposio “Lunarbase - Bauen fuer ein Leben auf dem Mond” (www.lunar-base.net) organizzato dalla DLR (Agenzia aerospaziale tedesca) e dalla TU Kaiserslautern. Scienziati, ingegneri, architetti e designer di tutto il mondo presentano i loro piani e le loro visioni per una possibile vita sulla Luna. Alcune nazioni tra le quali la Cina, la Russia e gli Stati Uniti stanno elaborando piani concreti per la costruzione di stazioni lunari come basi per missioni equipaggiate su Marte, con un orizzonte temporale intorno al 2020. La proposta degli studenti dei Laboratori di I anno di Progettazione architettonica, tenuti dal Prof. Gaetano Licata con la collaborazione del dottorando in Design Michele Cammarata nel nuovo corso di Laurea triennale in Scienze dell’Architettura (SdA) e nel Corso di Laurea quinquennale (4/s), è stata selezionata dal comitato organizzatore che ne ha richiesto l’elaborazione sotto forma di un Poster (A0) attualmente esposto durante il Simposio. Si tratta di un montaggio di modelli tridimensionali elaborati dagli studenti e denominati “multiple Wesen”. Questi modelli, in quanto concetti di architettura assolutamente astratti, si prestano a contribuire a quel bagaglio di conoscenze, visioni, sogni e immaginazione, che chiunque voglia “confrontarsi” con una realtĂ  solo immaginabile come quella della Luna, ha bisogno di “portare con sé” dalla Terra. Concetti mentali di spazi possibili – “Raumstrukturen” - a sostegno degli scienziati, per poter continuare a immaginare insieme sempre piĂą concretamene la vita e la ricerca direttamente sulla Luna. Pa, 13.05.2009 ([email protected]

    An agronomic evaluation of new safflower (Carthamus tinctorius L.) germplasm for seed and oil yields under Mediterraean climate conditions

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    Interest in oilseed crops for agro-industrial research and development projects has increased in the Mediterranean area, in recent years. Saffloower (Carthamus tinctorius L.) is of potential interest for agriculture mainly due to fatty acid content variability in the seed oil. The aim of this study was to assess the agronomic performance of 16 new safflower accessions together with safflower variety Montola 2000, used as a reference, in a semi-arid environment. Research was carried out in Sicily (Italy) from 2013–2014. Hierarchical cluster analysis carried out on the fatty acid composition of safflower accessions resulted in their division into four main groups. Linoleic, oleic and palmitic acids were the main fatty acids present in the accessions. Seed yield was 1.11 t ha-1 on average and seed oil content was found to be approximately 35.01% of dry matter on average. Positive and significant relationships between seed/oil yield and other tested traits were found. The carbon, hydrogen and nitrogen content as a percentage of dry matter varied greatly both for the above- and belowground plant parts on average. This study confirms the interest of safflower for both food and non-food applications, offering interesting prospects in semi-arid regions
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