Un nou dinosaure en una illa prehistòrica a l'Oceà Tetis

Una nova espècie de dinosaure, el Tethyshadros insularis, descobert a Itàlia, és l'objecte de la publicació d'un recent article per part de Fabio Dalla Vecchia, director de l'equip descubridor, del Institut Català de Paleontologia. El flamant dinosauri està emparentat amb la família dels herbívors hadrosauroides "bec d'ànec", però és anterior als hadrosaures nord-americans. "Antonio", que així es diu l'espècimen, va viure a finals del Cretàcic en una illa enmig de l'Oceà Tetis, un mar prehistòric que es trobava esquitxat d'illes que més tard formarien la massa continental de l'Europa occidental.Una nueva especie de dinosaurio, el Tethyshadros insularis, descubierto en Italia, es el objeto de la publicación de un reciente artículo por parte de Fabio Dalla Vecchia, el director del equipo que lo descubrió, del Institut Català de Paleontologia. El flamante dinosaurio está emparentado con la familia de los herbívoros hadrosauroides "pico de pato", pero es anterior a los hadrosaurios norteamericanos. "Antonio", que así se llama el espécimen, vivió a finales del Cretácico en una isla en medio del Océano Tetis, un mar prehistórico que se encontraba salpicado de islas que más tarde formarían la masa continental de la Europa occidental.A new dinosaur species, Tethyshadros insularis, found in Italy by the team led by Fabio Dalla Vecchia (Institut Català de Paleontologia), is the subject of a recent publication. The new dinosaur is related to the plant- eating dinosaurs family of "duck-billed" Hadrosaurids, but is more primitive than north-american hadrosaurs. The specimen, nicknamed "Antonio", lived at the end of the Cretaceous period in a small island in the middle of Tethys Ocean, a prehistoric sea between Africa and Europe

Heteropelta boboi n. gen., n. sp. an armored archosauriform (Reptilia: Archosauromorpha) from the Middle Triassic of Italy

Heteropelta boboi is a new archosauriform reptile from the upper Anisian of northeastern Italy represented by a fragment of dorsal armor with a row of neural arches of the dorsal vertebrae. The dorsal armor of the new taxon is composed of two columns of paramedian osteoderms and at least six columns of lateral osteoderms. Unlike other armored archosaurs, the osteoderms are imbricated with the posterior osteoderm overlapping the anterior one. The low neural arches bear small neural spines and long postzygapophyses. The osteoderms of the lateral columns increase in size and change in shape from the most medial to the most lateral columns. Among the Archosauriformes, only the non-archosaur proterochampsians Vancleavea campi, Litorosuchus somnii, and the doswelliids have dorsal armor comprised of more than two columns of osteoderms per side, but the morphology and arrangement of their osteoderms is unlike those of the new Italian taxon. A cladistic analysis of Archosauromorpha positions Heteropelta boboi as either a basal phytosaur or a basal suchian. However, a second cladistic analysis focused on armored archosaurs alternatively positions the new taxon as a basal archosauriform, basal suchian, basal loricatan or crocodylomorph. Better resolution of the phylogenetic relationships of Heteropelta boboi will likely be obtained only with the discovery of cranial and postcranial remains associated with its diagnostic armor elements

Performance analysis of a multi-plate thermal control system for space and planetary probes. Laboratory test and stratospheric flight results of the POLARIS experiment

This work of thesis aims to study the performances of a new concept of heat radiatorope

The unusual tail of Tethyshadros Insularis (Dinosauria, Hadrosauroidea) from the Adriatic Island of the European Archipelago

The basal hadrosauroid Tethyshadros insularis from the uppermost Cretaceous of NE Italy lived on an island of the European archipelago in the Tethys Ocean. The tail of this dinosaur presents several apomorphic traits respect to the tails of other coeval hadrosauroids of the archipelago and of hadrosauroids in general. The estimated total length of the tail of the holotypic specimen shows that the tail was long, accounting for at least 56% of the total body length, relatively stiff and deep proximally, whereas it was whip-like distally. The reconstruction of the tail musculature by comparison with that of living archosaurs and other dinosaurs suggests that the posterior shift of the first haemapophysis affected the size and shape of the M.m. caudofemorales with important consequences on the locomotion of T. insularis. Somewhat peculiar stance and gait for this dinosaur are suggested also by limb features. The posterior shift of the vent and consequent longer distal tract of the intestine or a longer cloaca could increase the space for urine storage and urinary water reabsorption. The posterior shift of the vent could imply also longer oviducts and plausibly an increased number of eggs per clutch. Tail apomorphies of T. insularis may be related to the rugged and water-depleted karst landscape where the Italian dinosaur lived. The two main specimens of T. insularis differ in robustness possibly because of sexual dimorphism, ontogeny or high intraspecific variability

The impact of active galactic nuclei on cooling flows

This thesis explores the role of active galactic nuclei (AGN) in the heating of the intracluster medium (ICM). In the centre of many clusters the radiative cooling tune of the ICM is much shorter than the Hubble time. Unless cooling is balanced by some form of heating, gas will flow into the cluster centre at rates up to ~ 1000 M© yr(^-1). Recent Chandra and XMM-Newton X-ray observations present almost no evidence that this is happening incluster cores. Moreover, they show that the ICM has a rather complex structure. Some of the features in the X-ray images can be explained as the interaction of the central AGN with the ICM. The most prominent feature are bubbles of hot and underdense gas inflated by jets coming from massive black holes residing in the centre of giant elliptical galaxies. These bubbles are thought to rise buoyantly through the ICM and heat the gas by depositing their energy. I start by introducing the cooling-flow problem and by summarising the current understanding of the ICM heating processes. I then introduce the adaptive mesh refinement (AMR) code FLASH that has been used for the simulations in this thesis and the development of new routines and modules. A model of AGN heating is then applied to model clusters to investigate three issues: (1) the quenching of the cooling-flow by injection of bubbles of energy; (2) the determination of the AGN duty cycle by using measurements of sound wave positions; (3) the presence of a mass threshold below which the heating process is no longer effective. I show that cooling can be effectively balanced by AGN heating in a cluster of mass 3 x lO(^14) Mo. Then, I argue that by using measurements of sound wave positions it is possible to determine the duty cycle of the AGN with good accuracy. Finally, I show that there is a threshold mass for which the heating process is ineffective. In the light of this, I discuss the importance of the process in shaping the luminosity function of galaxies. I also apply the heating model to a cluster that has formed in a cosmological environment and discuss how to improve the code performance

A revision of the anatomy of the Triassic Pterosaur Austriadraco Dallavecchiai Kellner, 2015 and of its diagnosis

Several skeletal elements preserved in the holotype and only specimen of the pterosaur Austriadraco dallavecchiai Kellner, 2015 (uppermost Triassic, Austria) have not been identified or have remained undescribed in previous works. They include important elements for the systematic and phylogenetic studies such as the femur, premaxillae and maxillary teeth. The broad bone initially considered the sternal plate is plausibly formed by the fused frontals, as already suggested by some authors. The diagnosis of Austriadraco dallavecchiai is amended on the basis of new information. The close relationship of Austriadraco dallavecchiai to Seazzadactylus venieri from the uppermost Triassic of Friuli (north-eastern Italy) is further supported by the morphological similarity between the two taxa (e.g. they share similar postorbital process of the jugal and dorsal process of the surangular)

The First Billion Years project: dark matter haloes going from contraction to expansion and back again

We study the effect of baryons on the inner dark matter profile of the first galaxies using the First Billion Years simulation between z=16-6 before secular evolution sets in. Using a large statistical sample from two simulations of the same volume and cosmological initial conditions, one with and one without baryons, we are able to directly compare haloes with their baryon-free counterparts, allowing a detailed study of the modifications to the dark matter density profile due to the presence of baryons during the first billion years of galaxy formation. For each of the ~ 5000 haloes in our sample we quantify the impact of the baryons using eta, defined as the ratio of dark matter mass enclosed in 100 pc in the baryonic run to its counterpart without baryons. During this epoch of rapid growth of galaxies, we find that many haloes of these first galaxies show an enhancement of dark matter in the halo centre compared to the baryon-free simulation, while many others show a deficit. We find that the mean value of eta is close to unity, but there is a large dispersion, with a standard deviation of 0.677. The enhancement is cyclical in time and tracks the star formation cycle of the galaxy; as gas falls to the centre and forms stars, the dark matter moves in as well. Supernova feedback then removes the gas, and the dark matter again responds to the changing potential. We study three physical models relating the motion of baryons to that of the dark matter: adiabatic contraction, dynamical friction, and rapid outflows. Abridged, see text for full abstractComment: accepted in MNRA

The First Billion Years project - IV: Proto-galaxies reionising the Universe

The contribution of stars in galaxies to cosmic reionisation depends on the star formation history in the Universe, the abundance of galaxies during reionisation, the escape fraction of ionising photons and the clumping factor of the inter-galactic medium (IGM). We compute the star formation rate and clumping factor during reionisation in a cosmological volume using a high-resolution hydrodynamical simulation. We post-process the output with detailed radiative transfer simulations to compute the escape fraction of ionising photons. Together, this gives us the opportunity to assess the contribution of galaxies to reionisation self-consistently. The strong mass and redshift dependence of the escape fraction indicates that reionisation occurred between z=15 and z=10 and was mainly driven by proto-galaxies forming in dark-matter haloes with masses between 1e7 and 1e8 solar mass. More massive galaxies that are rare at these redshifts and have significantly lower escape fractions contribute less photons to the reionisation process than the more-abundant low-mass galaxies. Star formation in the low-mass haloes is suppressed by radiative feedback from reionisation, therefore these proto-galaxies only contribute when the part of the Universe they live in is still neutral. After z~10, massive galaxies become more abundant and provide most of the ionising photons. In addition, we find that Population (Pop) III stars are too short-lived and not frequent enough to have a major contribution to reionisation. Although the stellar component of the proto-galaxies that produce the bulk of ionising photons during reionisation is too faint to be detected by the James Webb Space Telescope (JWST), these sources are brightest in the H-alpha and Ly-alpha recombination lines, which will likely be detected by JWST in deep surveys.Comment: 5 pages, 4 figures, accepted for publication in MNRAS letter

Modelagem e dimensionamento de um sistema de geração de energia a partir das ondas do oceano

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Araranguá. Engenharia de Energia.Este trabalho aborda a modelagem e o dimensionamento de um dispositivo de extração da energia proveniente das ondas do oceano, considerando a utilização de um conversor do tipo Coluna de Água Oscilante (CAO ou OWC, do inglês Oscillating Water Column), composto por tubos fixados nos pilares de uma plataforma de pesca, na cidade de Balneário Arroio do Silva/SC. Esta aplicação em particular representa uma condição de operação diferente do que já foi considerada em outros estudos sobre o tema. A modelagem deste dispositivo é realizada utilizando conceitos de mecânica dos fluidos, a fim de descrever as características físicas do escoamento do ar no interior do dispositivo, otimizar o dimensionamento do dispositivo e determinar as perdas de velocidade do escoamento devido à influência das paredes do tubo, as perdas de carga e o afunilamento. Para a conversão do movimento do ar em energia mecânica foi considerada a utilização de uma turbina Wells. A simulação no domínio do tempo foi realizada utilizando Matlab/Simulink levando em conta os parâmetros atuais, um regime específico das ondas e a análise dos fluidos realizada no Autodesk CFD. Os resultados obtidos permitem otimizar o dimensionamento do dispositivo e avaliar o desempenho do OWC sob a influência de diferentes fatores.This work discusses the modelling and the design of an energy extraction device from ocean waves, considering the use of a converter device called Oscillating Water Column (OWC), composed by fixed tubes in a concrete pillar of a fishing pier, in Balneário Arroio do Silva/SC - Brazil. This application in particular represents a different condition than has been considered in other studies on the subject. The modelling of this device is performed using concepts of fluid mechanics, in order to describe the physical characteristics of the air flow within the device. These concepts are also applied to optimize the device design and to determine the losses of flow velocity due to the influence of the tube's walls, the head losses and the contraction. The conversion of the air movement into mechanical energy is performed considering the use of a Wells turbine. The simulation in the time domain was performed using Matlab/Simulink taking into account the current parameters and a specific regime of the waves. The fluid analysis was performed using Autodesk CFD. The results allow to optimize the device design and to evaluate the performance of OWC under the influence of different factors

THE PRESENCE OF AN ORBITOANTORBITAL FENESTRA: FURTHER EVIDENCE OF THE ANUROGNATHID PECULIARITY WITHIN THE PTEROSAURIA

The anurognathids are peculiar pterosaurs characterized by broad skulls with very short rostra and broadly arched jaws. The presence of distinct or confluent external naris and antorbital fenestra in these pterosaurs has been debated in the last years. The relatively well-preserved specimens of Batrachognathus volans show that the antorbital fenestra was confluent with the orbit forming an enormous orbitoantorbital fenestra. This feature is evident also in Jeholopterus ningchengensis. The consequent modification of the matrices of two recently published phylogenetic analyses about the in-group pterosaur relationships shows that the Anurognathidae are a derived clade of non-monofenestratan pterosaurs. Anurognathidae (including also 'Dimorphodon' weintraubi according to the definition by Hone 2020) are still a scarcely known clade because only a few specimens have been adequately described in the literature