ARCHI: pipeline for light curve extraction of CHEOPS background star

High precision time series photometry from space is being used for a number of scientific cases. In this context, the recently launched CHEOPS (ESA) mission promises to bring 20 ppm precision over an exposure time of 6 hours, when targeting nearby bright stars, having in mind the detailed characterization of exoplanetary systems through transit measurements. However, the official CHEOPS (ESA) mission pipeline only provides photometry for the main target (the central star in the field). In order to explore the potential of CHEOPS photometry for all stars in the field, in this paper we present archi, an additional open-source pipeline module{\dag}to analyse the background stars present in the image. As archi uses the official Data Reduction Pipeline data as input, it is not meant to be used as independent tool to process raw CHEOPS data but, instead, to be used as an add-on to the official pipeline. We test archi using CHEOPS simulated images, and show that photometry of background stars in CHEOPS images is only slightly degraded (by a factor of 2 to 3) with respect to the main target. This opens a potential for the use of CHEOPS to produce photometric time series of several close-by targets at once, as well as to use different stars in the image to calibrate systematic errors. We also show one clear scientific application where the study of the companion light curve can be important for the understanding of the contamination on the main target.Comment: 14 pages, 13 figures, accepted for publication in MNRAS, all code available at https://github.com/Kamuish/arch

Reversible Transport of Interacting Brownian Ratchets

The transport of interacting Brownian particles in a periodic asymmetric (ratchet) substrate is studied numerically. In a zero-temperature regime, the system behaves as a reversible step motor, undergoing multiple sign reversals of the particle current as any of the following parameters are varied: the pinning potential parameters, the particle occupation number, and the excitation amplitude. The reversals are induced by successive changes in the symmetry of the effective ratchet potential produced by the substrate and the fraction of particles which are effectively pinned. At high temperatures and low frequencies, thermal noise assists delocalization of the pinned particles, rendering the system to recover net motion along the gentler direction of the substrate potential. The joint effect of high temperature and high frequency, on the other hand, induces an additional current inversion, this time favoring motion along the direction where the ratchet potential is steeper. The dependence of these properties on the ratchet parameters and particle density is analyzed in detail.Comment: 8 pages, 10 figure

Bioaugmentation strategies to enhance long chain fatty acids (LCFA) conversion to methane

Bioaugmentation of bioreactors with LCFA-degrading bacteria is a possibility for improving methane production from lipid-rich wastes/wastewaters. Cavaleiro et al. [1] has shown that methane production from oleate (unsaturated LCFA) is faster and more efficient in batch tests bioaugmented with Syntrophomonas zehnderi, a bacterium that is able to degrade a wide range of both saturated and unsaturated LCFA [2]. In this work, anaerobic sludge bioaugmentation with S. zehnderi was studied in order to evaluate: (I) the recovery of bioreactors after an episode of LCFA overload; (II) the potential for decreasing reactor start-up periods. The potential of using S. zehnderi for recovering LCFA-overloaded sludge was tested using anaerobic sludge collected from a oleate-fed bioreactor at three different operation times. Bioaugmentation batches were prepared with LCFA loaded biomasses in the presence of S. zehnderi. Controls were set using inactivated S. zehnderi. Methane yields of 72, 53 and 40% were obtained from the first, second and third collected sludge samples respectively. However, addition of S. zehnderi did not significantly improve LCFA conversion loaded-sludges as similar yields were achieved in non-bioaugmented controls. Fed-batch bioreactor start-up, using a non-acclimated sludge, was attempted in the presence of S. zehnderi. Assays were conducted in the presence and absence of both a solid microcarier (sepiolite) and a substoichiometric amount of ferric hydroxide. Blank (no oleate) and control assays (inactivated S. zehnderi) were also prepared. Bioaugmentation assays with sepiolite and ferric hydroxide showed the highest methane yield, with an observed methane yield 16% higher than in non-bioaugmented controls. The potential of bioaugmenting S. zehnderi as means to recover methanogenic activity of LCFA-loaded biomass was not demonstrated. However faster reactor start-up could be accomplished since higher methane yield was achieved in bioaugmented fed-batch assays in the presence of sepiolite with ferric hydroxide. [1] Cavaleiro, A.J., Sousa, D.Z. and Alves, M.M. 2010. Water Res 44:4940-7. [2] Sousa, D.Z., Smidt, H., Alves, M.M. and Stams, A.J.M. 2007. Int J Syst Evol Microbiol 57:609-15. Acknowledgments: This study has been funded by FEDER, through the COMPETE program, and by Portuguese funds, through Portuguese Foundation for Science and Technology (FCT), in the frame of the project FCOMP-01-0124-FEDER-014784. References

Adsorption heat pump optimization by experimental design and response surface methodology

The performance of commercial zeolites, with and without binder in its formulation (SYLOBEAD® MS C 548: 13X with binder; Köstrolith® 13XBFK and NaYBFK: 13X and NaY without binder, respectively), for water adsorption heating applications was compared in this work. Accounting for a Box-Behnken design with four factors (time of adsorption and desorption, tADS+DES; condensation temperature, Tcond; heat source temperature, THTF,hot; bed thickness, δ) and three levels, a set of 25 simulations per adsorbent was accomplished, and the performance of the adsorption units was evaluated through the coefficient of performance (COP) and the specific heating power (SHP). The results suggested that the presence of the binder in the formulation of 13X does not penalize the zeolite performance significantly, and that NaYBFK is the most promising material. For the latter solid, statistical outcomes were analyzed and insights about their usefulness to optimize the design and operation of adsorption heat pumps are provided. Pareto charts displaying the impact ranking of the factors upon COP and SHP are discussed, and simple equations are provided for the expeditious estimation of both indicators. Such models were utilized to map system performance and to select optimal geometric/operating parameters that meet specific performance requirements.publishe

O clássico no contemporâneo: o mito de Anfion em João Cabral de Melo Neto

O clássico, de uma forma ou outra, está presente na poesia contemporânea no que concerne não só ao aspecto formal, mas também, muitas vezes temático. Tais aspectos são perceptíveis no poema Fábula de Anfion, o qual pertence à obra Psicologia da Composição, livro de um dos maiores poetas de língua portuguesa: João Cabral de Melo Neto. Objetivamos, então, elencar como se constroem certas características presentes nos âmbitos formal e de sentido do poema construído por Cabral, que trabalha a imagem de um personagem mitológico grego, Anfion, aludindo à perspectiva da inspiração clássica relacionada as ninfas, a qual será desconstruída no decorrer do poema que será analisado. Dessa maneira, utilizaremos conceitos teóricos acerca da composição clássica presente em João Cabral, observando, assim, sua linguagem concisa e econômica, a qual configura um caráter de exigência formal. Esse rigor cabralino se reflete no aspecto “prosaico” de seu fazer “poético” como afirma Secchin (1996)

Proteostasis networks in aging: novel insights from text-mining approaches

Aging is a topic of paramount importance in an increasingly elderly society and has been the focus of extensive research. Protein homeostasis (proteostasis) decline is a hallmark in aging and several age-related diseases, but which specific proteins and mechanisms are involved in proteostasis (de)regulation during the aging process remain largely unknown. Here, we used different text-mining tools complemented with protein–protein interaction data to address this complex topic. Analysis of the integrated protein interaction networks identified novel proteins and pathways associated to proteostasis mechanisms and aging or age-related disorders, indicating that this approach is useful to identify previously unknown links and for retrieving information of potential novel biomarkers or therapeutic targets.info:eu-repo/semantics/acceptedVersio

Supramolecular ultra-short dehydropeptide-based hydrogels as potential affordable nanocarriers

A library of Cbz-protected dehydrodipeptides was synthesised and evaluated as minimalist hydrogels. The molecular aggregation, self-assembly, gelation and biocompatibility were thoroughly studied through fluorescence spectroscopy, and the mechanical properties were assessed. The compounds that afforded hydrogels were evaluated as drug delivery systems for curcumin and doxorubicin using biomembrane models.UIDB/04650/2020; UIDB/00686/2020; PTDC/QUI-QFI/28020/2017; PTDC/QUI-QOR/29015/2017; SFRH/BD/144017/201