730 research outputs found

    The Amateur Sky Survey Mark III Project

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    The Amateur Sky Survey (TASS) is a loose confederation of amateur and professional astronomers. We describe the design and construction of our Mark III system, a set of wide-field drift-scan CCD cameras which monitor the celestial equator down to thirteenth magnitude in several passbands. We explain the methods by which images are gathered, processed, and reduced into lists of stellar positions and magnitudes. Over the period October, 1996, to November, 1998, we compiled a large database of photometric measurements. One of our results is the "tenxcat" catalog, which contains measurements on the standard Johnson-Cousins system for 367,241 stars; it contains links to the light curves of these stars as well.Comment: 20 pages, including 4 figures; additional JPEG files for Figures 1, 2. Submitted to PAS

    Early predictors of phonological and morphological awareness and the link with reading : evidence from children with different patterns of early deficit

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    This study examines the contribution of early phonological processing (PP) and language skills on later phonological awareness (PA) and morphological awareness (MA), as well as the links among PA, MA, and reading. Children 4–6 years of age with poor PP at the start of school showed weaker PA and MA 3 years later (age 7–9), regardless of their language skills. PA and phonological and morphological strategies predict reading accuracy, whereas MA predicts reading comprehension. Our findings suggest that children with poor early PP are more at risk of developing deficits in MA and PA than children with poor language. They also suggest that there is a direct link between PA and reading accuracy and between MA and reading comprehension that cannot be accounted for by strategy use at the word level

    Application of the Cre-loxP system for multiple gene disruption in the yeast kluyveromyces marxianus

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    The yeast Kluyveromyces marxianus presents several interesting features that make this species a promising industrial yeast for the production of several compounds. In order to take full advantage of this yeast and its particular properties, proper tools for gene disruption and metabolic engineering are needed. The Cre-loxP system is a very versatile tool that allows for gene marker rescue, resulting in mutant strains free of exogenous selective markers, which is a very important aspect for industrial application. As the Cre-loxP system works in some non-conventional yeasts, namely Kluyveromyces lactis, we wished to know whether it also works in K. marxianus. Here, we report the validation of this system in K. marxianus CBS 6556, by disrupting two copies of the LAC4 gene, which encodes a ÎČ-galactosidase activity.Coordenação de Aperfeiçoamento de Pessoal de NĂ­vel Superior - (CAPES), Brazil;AgĂȘncia de Inovação - projecto UMINHO/POCI-Zimlac/BI/2/0

    Experimental validation of an electronic counting device to determine flight activity of honey bees (Apis mellifera L.)

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    Ein Funktionsprototyp des BienenzĂ€hlers BeeCheck sollte in dieser Arbeit auf seine Genauigkeit hin ĂŒberprĂŒft werden, um seine Tauglichkeit fĂŒr den wissenschaft­lichen Einsatz zu validieren. Hierzu wurden zwei unterschiedliche AnsĂ€tze verfolgt: (i) Vergleich der elektronischen Daten des ZĂ€hlgerĂ€tes durch Videoaufnahmen von Ein- und AusflĂŒgen mit manueller Auswertung durch einen Beobachter sowie (ii) die Validierung mittels „RĂ€ubertest“ im bienendichten Zelt. Die Ergebnisse zeigten eine zu erwartende Temperatur AbhĂ€ngigkeit der Flug­aktivitĂ€t sowie die FehleranfĂ€lligkeit bei gewissen AktivitĂ€ten am Flugloch. So waren unterschiedliche Geschwindigkeiten, sich entgegenkommende oder im Flugloch verharrende Bienen, sowie sich vor- und rĂŒckwĂ€rts bewegende Bienen eine Herausforderung fĂŒr den Algorithmus, der aus den gemessenen Sensordaten die Bienentransaktionen ableitet. Um diese GrenzfĂ€lle zu minimieren und die ZĂ€hlgenauigkeit zu erhöhen, ist es notwendig den Algorithmus entsprechend korrektiv anzupassen. Dies soll im Folgeprojekt „Etablierung digitaler Indikatoren der BienenvitalitĂ€t in Agrarlandschaften – V-I-Bee“ angegangen werden.In this work, a functional prototype of the BeeCheck counting device was evaluated for its accuracy to validate its suitability for scientific purposes. Two different approaches were applied: (i) we manually compared electronic data of the counting device by video recordings of entry and exit events, and (ii) by using the so-called “robber’s test” in a tunnel tent. The results showed an expected temperature dependency of the general flight activity. Difficulties occurred with certain activities at the hive entrance. The various running speeds of individuals, approaching or stuck bees, and bees moving back and forth in the tube were a challenge for sensor technology and the mathematical algorithm. To minimize such mistakes and to increase the counting accuracy, it is necessary to correct the algorithm accordingly. This will be addressed in the “V-I-Bee” follow-up project and future perspectives of using an improved counting device are discussed

    Lasing mechanisms in organic photonic crystal lasers with two-dimensional distributed feedback

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    We present a detailed experimental and theoretical investigation of the lasing characteristics of organic photonic crystal lasers. These lasers are based on strongly modulated two-dimensional polymer surface relief structures on which thin films of optically active organic materials have been deposited. We determine the in-plane photonic band structure of the corresponding quasiguided modes within an effective two-dimensional model. In addition, we calculate the total (three-dimensional) losses associated with these modes. This allows us to identify the lasing thresholds for square lattice geometries and to understand the emission pattern

    Recent progress in the discovery of macrocyclic compounds as potential anti-infective therapeutics

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    Novel therapeutic strategies are urgently needed for the treatment of serious diseases caused by viral, bacterial and parasitic infections, because currently used drugs are facing the problem of rapidly emerging resistance. There is also an urgent need for agents that act on novel pathogen-specific targets, in order to expand the repertoire of possible therapies. The high throughput screening of diverse small molecule compound libraries has provided only a limited number of new lead series, and the number of compounds acting on novel targets is even smaller. Natural product screening has traditionally been very successful in the anti-infective area. Several successful drugs on the market as well as other compounds in clinical development are derived from natural products. Amongst these, many are macrocyclic compounds in the 1-2 kDa size range. This review will describe recent advances and novel drug discovery approaches in the anti-infective area, focusing on synthetic and natural macrocyclic compounds for which in vivo proof of concept has been established. The review will also highlight the Protein Epitope Mimetics (PEM) technology as a novel tool in the drug discovery process. Here the structures of naturally occurring antimicrobial and antiviral peptides and proteins are used as starting points to generate novel macrocyclic mimetics, which can be produced and optimized efficiently by combinatorial synthetic methods. Several recent examples highlight the great potential of the PEM approach in the discovery of new anti-infective agents

    ContrĂŽle du Phomopsis, maladie Ă©mergente, en culture de carotte porte-graĂźne

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    The first triangular browning umbels caused by Diaporthe angelicae on carrot seed crops were observed in France in 2007. This fungal phytopathogen negatively impacted carrot seed production. Little is known about this fungus. In order to control it in carrot seed production, a better understanding of its life cycle and its epidemiology is required. So, this is the reason why a three-years research project named DIAPOCAR was initiated in 2012. It appears that flower is the main sensitive organ and flowering the most sensitive stage of the umbel. In the field, contaminations are particularly observed during flowering of the umbels of order I and II if the weather is favourable to disease. Field fungicide trials show significant efficacy differences between fungicides and only three of them are efficient against carrot phomopsis. Finally, model simulations with the sunflower phomopsis model are promising and this tool to aid decision-making can be used to apply fungicides only when the weather is favourable to the disease. It should help carrot seed growers to determine the best timing for fungicide applications. Thus, a greater understanding of the biology of this fungus has led to a better control of phomopsis on carrot seed crops

    Ifabp Levels Predict Visceral Malperfusion in the First Hours After Open Thoracoabdominal Aortic Repair

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    INTRODUCTION: Intestinal ischemia after open thoracoabdominal aortic repairs, is a rare but devastating complication, associated with high mortality. Notoriously challenging to diagnose, visceral malperfusion necessitates immediate surgical attention. Intestinal fatty acid-binding protein (IFABP) has been proposed as a biomarker for the diagnosis of intestinal wall damage. In this prospectively conducted, observational study we evaluated the diagnostic capacity of IFABP levels in patients\u27 serum and their correlation with visceral malperfusion. METHODS: 23 patients undergoing open thoracoabdominal aortic repairs were included in this study and 8 of them were diagnosed postoperatively with visceral malperfusion-defined as a partial or complete thrombotic occlusion of the superior mesenteric artery and/or the coeliac trunk. IFABP levels and laboratory parameters often associated with intestinal ischemia (leucocytes, CRP, PCT and lactate) were measured at baseline, directly postoperatively, and at 12, 24 and 48 h after surgery. Postoperative visceral malperfusion-as revealed in CT angiography-was assessed and the predictive ability of IFABP levels to detect visceral malperfusion was evaluated with receiver-operator curve analysis. RESULTS: Patients with visceral malperfusion had a relevant risk for a fatal outcome ( CONCLUSION: We conclude, that IFABP measurements during the first postoperative hours after open thoracoabdominal aortic surgery can be a valuable tool for reliable and timely detection of visceral malperfusion
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