New multilocus phylogeny reorganises the family Macrobiotidae (Eutardigrada) and unveils complex morphological evolution of the Macrobiotus hufelandi group

The family Macrobiotidae is one of the most speciose and diverse groups among tardigrades. Although there have been attempts to reconstruct the phylogeny of this family, the evolutionary relationships within Macrobiotidae are only superficially determined as available genetic data cover only a small fraction of this vast group. Here, we present the first extensive molecular phylogeny of the family based on four molecular markers (18S rRNA, 28Sr RNA, ITS-2 and COI) associated with detailed morphological data for the majority of taxa. The phylogenetic analysis includes nearly two hundred sequences representing more than sixty species, including sixteen taxa that have never been sequenced and/or analysed phylogenetically before. Our results recovered a new monophyletic group, comprising Macrobiotus spectabilis Thulin, 1928 and Macrobiotus grandis Richters, 1911, for which we erect a new genus, Sisubiotus gen. nov., to accommodate its evolutionary distinctiveness. The largest, so far, dataset for the family Macrobiotidae showed that the genus Xerobiotus is nested within the clade representing the genus Macrobiotus deeper than it was earlier assumed, therefore we propose to suppress Xerobiotus and transfer its species to Macrobiotus. Moreover, mapping key morphological traits onto macrobiotid phylogeny exposed complex evolution of phenotypes within the Macrobiotus hufelandi group, i.e. Macrobiotus s.s. Finally, our findings enabled a detailed revision and discussion on species compositions of the most ubiquitous tardigrade genera, species groups and species complexes, which resulted in changes of taxonomic statuses of a number of macrobiotid species. All this contributes to the reconstruction of the morphological evolution within Macrobiotidae

Wideband Fast Kernel-Independent Modeling of Large Multiscale Structures Via Nested Equivalent Source Approximation

We propose a wideband fast kernel-independent modeling of large multiscale structures; we employ a nested equivalent source approximation (NESA) to compress the dense system matrix. The NESA was introduced by these authors for low and moderate frequency problems (smaller than a few wavelengths); here, we introduce a high-frequency NESA algorithm, and propose a hybrid version with extreme wideband properties. The equivalent sources of the wideband NESA (WNESA) are obtained by an inverse-source process, enforcing equivalence of radiated fields on suitably defined testing surfaces. In the low-frequency region, the NESA is used unmodified, with a complexity of mathcal{O}(N) . In the high-frequency region, in order to obtain a fixed rank matrix compression, we hierarchically divide the far coupling space into pyramids with angles related to the peer coupling group size, and the NESA testing surfaces are defined as the boundaries of the pyramids. This results in a directional nested low-rank (fixed rank) approximation with mathcal{O}(Nlog {N}) computational complexity that is kernel independent; overall, the approach yields wideband fast solver for the modeling of large structures that inherits the efficiency and accuracy of low-frequency NESA for multiscale problems. Numerical results and discussions demonstrate the validity of the proposed work

The evolutionary history and functional divergence of trehalase (treh) genes in insects

Trehalases (treh) have been found in different organisms, such as bacteria, fungi, yeast, nematodes, insects, vertebrates and plants. Their biochemical properties are extremely variable and not yet fully understood. Gene expression patterns have shown differences among insect species suggesting a potential functional diversification of trehalase enzymes during their evolution. A second gene family encoding for enzymes with hypothetical trehalase activity has bene been repeatedly annotated in insect genome as acid trehalases/acid trehalase-like (ath), but its functional role is still not clear. The currently available large amount of genomic data from many insect species may enable deeper studies allowing a better understanding of the evolutionary history, the phylogenetic relationships and possible roles of trehalase encoding genes in this taxon. The aim of the present study is to infer the evolutionary history of trehalases and acid trehalase genes in insects and analyse the trehalase functional divergence during their evolution, combining nucleotides sequences phylogenyphylogenetic, protein conservation and genomic synteny/colinearity analyses

A PPP kinematic application on historical GPS data: the reprocessing of the ITASE98-99 Antarctica mission height profiles

The analysis of altimetric profiles in Antarctica and their evolution over the years is a sensitive topic for the scientific community since it helps understand the effects of climate change that the continent undergoes. Different geomatic techniques, including the GNSS technology, can be employed to obtain altimetric profiles. However, the GNSS differenced approaches, such as the Post Processing Kinematic, are hardly usable to define long profiles in Antarctica because of the low number of CORS stations. In these conditions, the Precise Point Positioning (PPP) approach is a valid alternative to avoid processing very long baselines. The aim of this article is to define a standard procedure for the processing of historical GPS data, thanks to the availability of a dataset from the International Trans-Antarctic Scientific Expedition, which took place between 1998 and 1999 (ITASE98-99). This expedition focused on mapping the Antarctic territory, subdividing it by nations of influence, using geophysical and geodetic technologies, including GPS. The altimetric profiles had already been calculated in 2002 by the Geomatics group of the University of Bologna using the Gipsy-OASIS II software. In this work, the new version of the JPL software, GipsyX, is used to apply the newly implemented models and reprocessed products. The calibration of the processing parameters leading to the final PPP solution is described in the paper, including details on the implementation of a post-processing filtering procedure. The average a posteriori elevation error is 4.6 cm, while 99% of them are within 27 cm. The comparison of the new results to both the previous processing and the REMA elevation model shown that about double the number of solutions are now available, meter-level elevation spikes have been avoided, and a half meter bias is now reduced to a few centimeters. Given the almost 15 years difference between the 1999.0 expedition epoch and the REMA reference epoch, the obtained results can be used to study accumulation/erosion effects on the Antarctica ice sheet

Infantile epilepsy associated with mosaic 2q24 duplication including SCN2A and SCN3A

AbstractEpilepsies can be caused by specific genetic anomalies or by non-genetic factors, but in many cases the underlying cause is unknown.Mutations in the SCN1A and SCN2A genes are reported in childhood epilepsies; in particular SCN1A was found mutated in patients with Dravet syndrome and with generalized epilepsy with febrile seizures plus (GEFS+).In this paper we report a patient presenting with an atypical epileptic syndrome whose phenotype partially overlaps both Dravet syndrome and benign familial neonatal-infantile seizures (BFNIS).Array-CGH analysis suggested the presence of a mosaic duplication (about 12Mb) at the level of chromosome 2q23.3q24.3 involving SCN2A and SCN3A genes. Additional analyses (radiolabeled RFLP and quantitative PCR) confirmed the mosaicism of the duplication.We suggest that the array-CGH analysis is mandatory for children presenting with epilepsy and psycho-motor retardation even without dysmorphisms or other clinical features suggesting a specific genetic/epileptic syndrome. The analysis must nevertheless be performed taking into account the possibility of a mosaicism

Testing current synthesis models of the X-ray background

We present synthesis models of the X-ray background where the available X-ray observational constraints are used to derive information on the AGN population properties. We show the need for luminous X-ray absorbed AGNs, the QSO2s, in reproducing the 2-10 keV source counts at relatively bright fluxes. We compare a model where the evolution of absorbed AGNs is faster than that of unabsorbed ones, with a standard model where absorbed and unabsorbed AGNs evolve at the same rate. It is found that an increase by a factor of ~2 from z=0 to z~1.3 in the ratio between absorbed and unabsorbed AGNs would provide a significant improvement in the data description. Finally, we make predictions on the AGNs to be observed in deep X-ray surveys which contain information on the AGN space density at high redshift.Comment: 11 pages with 8 figures, A&A accepte