Organic compounds on comet 67P/Churyumov-Gerasimenko revealed by COSAC mass spectrometry

Comets harbor the most pristine material in our solar system in the form of ice, dust, silicates, and refractory organic material with some interstellar heritage. The evolved gas analyzer Cometary Sampling and Composition (COSAC) experiment aboard Rosetta's Philae lander was designed for in situ analysis of organic molecules on comet 67P/Churyumov-Gerasimenko. Twenty-five minutes after Philae's initial comet touchdown, the COSAC mass spectrometer took a spectrum in sniffing mode, which displayed a suite of 16 organic compounds, including many nitrogen-bearing species but no sulfur-bearing species, and four compounds-methyl isocyanate, acetone, propionaldehyde, and acetamide-that had not previously been reported in comets.

Una intrusa en la habitación : Una escena multivalente entre la Antigüedad Tardía y la Edad Media

En el relato en alto alemán medio (Märe) El galardón del mundo de Konrad von Würzburg, el protragonista es sorprendido en su habitación por la aparición de "FrauWelt", la alegoría femenina del mundo. Se trata de uno de los testimonios más antiguo de esta figura que gozará de gran popularidad en los siguientes dos siglos. El presente trabajo intenterá demostrar que, para ser comprendida en toda su complejidad, la escena de la aparición repentina de la mujer en la habitación requiere ser interpretada como un eslabón en una tradición de textos que se remontan a la Antigüedad Tardía. Los textos a considerar son Consolatio Philosophiae de Boecio, la vida de San Bernardo de Claraval según Guillermo de San Thierry, el poema Orandi nova gratia de pseudo-Godofredo de Reims, Perceval de Chrétien de Troyes, Parzival de Wolfram von Eschenbach y Partonopeu de Blois (tanto la anónima versión francesa de como en la alemana de Konrad von Würzburg). El denominador común de todas ellas que nos permitirá compararlas e incluso rastrear una tradición es el relato de la aparició misteriosa y repentina de una mujer en la habitación en la que se encuentra un hombre solitario. La tesis central es que los testimonios pueden clasificarse en dos grupos según el objetivo perseguido por la figura femenina: aquellos en los que la mujer aparece como seductora (o al menos la posibilidad de una relación sexual es fundamental para la escena) y aquellos en los que busca instruir al hombre. El relato de Konrad von Würzburg une ambas tradiciones en el motivo de Frau Welt y de esta mezcla deriva su particular pluralidad de sentidos.

Una intrusa en la habitación : Una escena multivalente entre la Antigüedad Tardía y la Edad Media

En el relato en alto alemán medio (Märe) El galardón del mundo de Konrad von Würzburg, el protragonista es sorprendido en su habitación por la aparición de "FrauWelt", la alegoría femenina del mundo. Se trata de uno de los testimonios más antiguo de esta figura que gozará de gran popularidad en los siguientes dos siglos. El presente trabajo intenterá demostrar que, para ser comprendida en toda su complejidad, la escena de la aparición repentina de la mujer en la habitación requiere ser interpretada como un eslabón en una tradición de textos que se remontan a la Antigüedad Tardía. Los textos a considerar son Consolatio Philosophiae de Boecio, la vida de San Bernardo de Claraval según Guillermo de San Thierry, el poema Orandi nova gratia de pseudo-Godofredo de Reims, Perceval de Chrétien de Troyes, Parzival de Wolfram von Eschenbach y Partonopeu de Blois (tanto la anónima versión francesa de como en la alemana de Konrad von Würzburg). El denominador común de todas ellas que nos permitirá compararlas e incluso rastrear una tradición es el relato de la aparició misteriosa y repentina de una mujer en la habitación en la que se encuentra un hombre solitario. La tesis central es que los testimonios pueden clasificarse en dos grupos según el objetivo perseguido por la figura femenina: aquellos en los que la mujer aparece como seductora (o al menos la posibilidad de una relación sexual es fundamental para la escena) y aquellos en los que busca instruir al hombre. El relato de Konrad von Würzburg une ambas tradiciones en el motivo de Frau Welt y de esta mezcla deriva su particular pluralidad de sentidos.

Alternate furrow irrigation of four fresh-market tomato cultivars under semi-arid condition of Ethiopia – Part I: Effect on fruit yield and quality

Scarcity of freshwater due to recurrent drought threatens the sustainable crop production in semi-arid regions of Ethiopia. Deficit irrigation is thought to be one of the promising strategies to increase water use efficiency (WUE) under scarce water resources. A study was carried out to investigate the effect of alternate furrow irrigation (AFI), deficit irrigation (DI) and full irrigation (FI) on marketable fruit yield, WUE and physio-chemical quality of four fresh-market tomato cultivars (Fetan, Chali, Cochoro and ARP Tomato d2) in 2013 and 2014. The results showed that marketable yield, numbers of fruits per plant and fruit size were not significantly affected by AFI and DI irrigations. WUE under AFI and DI increased by 36.7% and 26.1%, respectively with close to 30% irrigation water savings achieved. A different response of cultivars to irrigation treatments was found for marketable yield, number of fruits and fruit size, WUE, total soluble solids (TSS) of the fruit juice, titratable acids (TA) and skin thickness. Cochoro and Fetan performed well under both deficit irrigation treatments exhibited by bigger fruit size which led to higher WUE. ARP Tomato d2 showed good yields under well-watered conditions. Chali had consistently lower marketable fruit yield and WUE. TSS and TA tended to increase under deficit irrigation; however, the overall variations were more explained by irrigation treatments than by cultivars. It was shown that AFI is a suitable deficit irrigation practice to increase fresh yield, WUE and quality of tomato in areas with low water availability. However, AFI requires suitable cultivars in order to exploit its water saving potential.

Alternate furrow irrigation of four fresh-market tomato cultivars under semi-arid condition of Ethiopia – Part II: Physiological response

Understanding the variation in physiological response to deficit irrigation together with better knowledge on physiological characteristics of different genotypes that contribute to drought adaptation mechanisms would be helpful in transferring different irrigation technologies to farmers. A field experiment was carried to investigate the physiological response of four tomato cultivars (Fetan, Chali, Cochoro and ARP Tomato d2) to moderate water deficit induced by alternate furrow irrigation (AFI) and deficit irrigation (DI) under semi-arid condition of Ethiopia during 2013 and 2014. The study also aimed at identifying physiological attributes to the fruit yield of tomato under different deficit irrigation techniques. A factorial combination of irrigation treatments and cultivar were arranged in a complete randomized design with three replicates. Results showed that stomatal conductance (g_s) was significantly reduced while photosynthetic performance measured as chlorophyll fluorescence (Fv’/Fm’), relative water content (RWC) and leaf ash content remained unaffected under deficit irrigations. Significant differences among cultivars were found for water use efficiency (WUE), g_s, chlorophyll content (Chl_SPAD), normal difference vegetation index (NDVI), leaf ash content and fruit growth rate. However, cultivar differences in WUE were more accounted for by the regulation of g_s, therefore, g_s could be useful for breeders for screening large numbers of genotypes with higher WUE under deficit irrigation condition. The study result also demonstrated that cultivar with traits that contribute to achieve higher yields under deficit irrigation strategies has the potential to increase WUE.

Primordial black holes from multi-field inflation

In this master's thesis, the formation of Primordial Black Holes (PBHs) in the context of multi-field inflation is studied. In these models, the interaction of isocurvature and curvature perturbations can lead to a significant enhancement of the latter, and to the subsequent production of PBHs. Depending on their mass, these can account for a significant fraction (or, in some cases, the entirety) of the universe's Dark Matter content. After studying the theoretical framework of generic N-field inflationary models, the focus is restricted to the two-field case, for which a few concrete realisations are analysed. A numerical code (written in Wolfram Mathematica) is developed to make quantitative predictions for the main inflationary observables, notably the scalar power spectra. Parallelly, the production of PBHs due to the dynamics of 2-field inflation is examined: their mass, as well as the fraction of Dark Matter they represent, is calculated for the models considered previously.