Size Matters: Microservices Research and Applications

In this chapter we offer an overview of microservices providing the introductory information that a reader should know before continuing reading this book. We introduce the idea of microservices and we discuss some of the current research challenges and real-life software applications where the microservice paradigm play a key role. We have identified a set of areas where both researcher and developer can propose new ideas and technical solutions.Comment: arXiv admin note: text overlap with arXiv:1706.0735

Low mass young stars in the Milky Way unveiled by DBSCAN and Gaia EDR3. Mapping the star forming regions within 1.5 Kpc

With an unprecedented astrometric and photometric data precision, Gaia EDR3 gives us, for the first time, the opportunity to systematically detect and map in the optical bands, the low mass populations of the star forming regions (SFRs) in the Milky Way. We provide a catalogue of the Gaia EDR3 data (photometry, proper motions and parallaxes) of the young stellar objects (YSOs) identified in the Galactic Plane (|b|<30 deg) within about 1.5 kpc. The catalogue of the SFRs to which they belong is also provided to study the properties of the very young clusters and put them in the context of the Galaxy structure. We applied the machine learning unsupervised clustering algorithm DBSCAN on a sample of Gaia EDR3 data photometrically selected on the region where very young stars (t<10 Myr) are expected to be found, with the aim to identify co-moving and spatially consistent stellar clusters. A subsample of 52 clusters, selected among the 7323 found with DBSCAN, has been used as template data set, to identify very young clusters from the pattern of the observed color-absolute magnitude diagrams through a pattern match process. We find 124440 candidate YSOs clustered in 354 SFRs and stellar clusters younger than 10 Myr and within about 1.5 Kpc. In addition, 65863 low mass members of 322 stellar clusters located within about 500 pc and with ages 10 Myr<t<100 Myr were also found. The selected YSOs are spatially correlated with the well known SFRs. Most of them are associated with well concentrated regions or complex structures of the Galaxy and a substantial number of them have been recognized for the first time. The massive SFRs, such as, for example, Orion, Sco-Cen and Vela, located within 600-700 pc trace a very complex three-dimensional pattern, while the farthest ones seem to follow a more regular pattern along the Galactic Plane

Models of Star-Planet Magnetic Interaction

Magnetic interactions between a planet and its environment are known to lead to phenomena such as aurorae and shocks in the solar system. The large number of close-in exoplanets that were discovered triggered a renewed interest in magnetic interactions in star-planet systems. Multiple other magnetic effects were then unveiled, such as planet inflation or heating, planet migration, planetary material escape, and even modification of the host star properties. We review here the recent efforts in modelling and understanding magnetic interactions between stars and planets in the context of compact systems. We first provide simple estimates of the effects of magnetic interactions and then detail analytical and numerical models for different representative scenarii. We finally lay out a series of future developments that are needed today to better understand and constrain these fascinating interactions.Comment: 23 pages, 10 figures, accepted as a chapter in the Handbook of Exoplanet

Identification of the Midgut Microbiota of An. stephensi and An. maculipennis for Their Application as a Paratransgenic Tool against Malaria

The midgut microbiota associated with Anopheles stephensi and Anopheles maculipennis (Diptera: Culicidae) was investigated for development of a paratransgenesis-based approach to control malaria transmission in Eastern Mediterranean Region (EMR). Here, we present the results of a polymerase chain reaction (PCR) and biochemical-based approaches to identify the female adult and larvae mosquitoe microbiota of these two major malaria vectors, originated from South Eastern and North of Iran. Plating the mosquito midgut contents from lab-reared and field-collected Anopheles spp. was used for microbiota isolation. The Gram-negative and Gram-positive bacterial colonies were identified by Gram staining and specific mediums. Selected colonies were identified by differential biochemical tests and 16S rRNA gene sequence analysis. A number of 10 An. stephensi and 32 An. maculipennis adult mosquitoes and 15 An. stephensi and 7 An. maculipennis larvae were analyzed and 13 sequences of 16S rRNA gene bacterial species were retrieved, that were categorized in 3 classes and 8 families. The majority of the identified bacteria were belonged to the γ-proteobacteria class, including Pseudomonas sp. and Aeromonas sp. and the others were some closely related to those found in other vector mosquitoes, including Pantoea, Acinetobacter, Brevundimonas, Bacillus, Sphingomonas, Lysinibacillus and Rahnella. The 16S rRNA sequences in the current study aligned with the reference strains available in GenBank were used for construction of the phylogenetic tree that revealed the relatedness among the bacteria identified. The presented data strongly encourage further investigations, to verify the potential role of the detected bacteria for the malaria control in Iran and neighboring countries

Midgut microbiota of the malaria mosquito vector Anopheles gambiae and Interactions with plasmodium falciparum Infection

The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.Institut de Recherche pour le Developpement (IRD); French Agence Nationale pour la Recherche [ANR-11-BSV7-009-01]; European Community [242095, 223601]info:eu-repo/semantics/publishedVersio

X-Ray Spectroscopy of Stars

(abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense, of X-ray spectra from the solar corona. X-ray emission from cool stars is indeed ascribed to magnetically trapped hot gas analogous to the solar coronal plasma. Coronal structure, its thermal stratification and geometric extent can be interpreted based on various spectral diagnostics. New features have been identified in pre-main sequence stars; some of these may be related to accretion shocks on the stellar surface, fluorescence on circumstellar disks due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot stars clearly dominate the interaction with the galactic interstellar medium: they are the main sources of ionizing radiation, mechanical energy and chemical enrichment in galaxies. High-energy emission permits to probe some of the most important processes at work in these stars, and put constraints on their most peculiar feature: the stellar wind. Here, we review recent advances in our understanding of cool and hot stars through the study of X-ray spectra, in particular high-resolution spectra now available from XMM-Newton and Chandra. We address issues related to coronal structure, flares, the composition of coronal plasma, X-ray production in accretion streams and outflows, X-rays from single OB-type stars, massive binaries, magnetic hot objects and evolved WR stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures (partly multiple); some corrections made after proof stag

The Gaia-ESO Survey: Hydrogen lines in red giants directly trace stellar mass

Red giant stars are perhaps the most important type of stars for Galactic and extra-galactic archaeology: they are luminous, occur in all stellar populations, and their surface temperatures allow precise abundance determinations for many different chemical elements. Yet, the full star formation and enrichment history of a galaxy can be traced directly only if two key observables can be determined for large stellar samples - age and chemical composition. While spectroscopy is a powerful method to analyse the detailed abundances of stars, stellar ages are the "missing link in the chain", since they are not a direct observable. However, spectroscopy should be able to estimate stellar masses, which for red giants directly infer ages provided their chemical composition is known. Here we establish a new empirical relation between the shape of the hydrogen line in the observed spectra of red giants and stellar mass determined from asteroseismology. The relation allows to determine stellar masses and ages with the accuracy of 10-15%. The method can be used with confidence for stars in the following range of stellar parameters: 4000 < Teff < 5000 K, 0.5 < log g < 3.5, -2.0 < [Fe/H] < 0.3, and luminosities log L/LSun < 2.5. Our analysis provides observational evidence that the Halpha spectral characteristics of red giant stars are tightly correlated with their mass and therefore their age. We also show that the method samples well all stellar populations with ages above 1 Gyr. Targeting bright giants, the method allows to obtain simultaneous age and chemical abundance information far deeper than would be possible with asteroseismology, extending the possible survey volume to remote regions of the Milky Way and even to neighbouring galaxies like Andromeda or the Magellanic Clouds already with present instrumentation, like VLT and Keck facilities