2,101 research outputs found
Macroevolutionary patterns in cranial and lower jaw shape of ceratopsian dinosaurs (dinosauria, ornithischia). phylogeny, morphological integration, and evolutionary rates
Organisms: Ceratopsians were herbivorous, beaked dinosaurs, ranging from 1 m to 9 m in body length, usually four-footed, and with a bony frill that extended backwards from the cranium over the nape of the neck. Known from Asia, Europe, and North America, they appeared in the Late Jurassic and persisted until the end of the Late Cretaceous.
Questions: Which evolutionary processes drive the phenotypic evolution of skulls and lower jaws within Ceratopsia? What is the degree of morphological integration between the skull and lower jaw, and between the snout and frill among clades? Finally, are there any morphological evolution rate shifts across the ceratopsian phylogeny?
Data: Photographs from 121 ceratopsian skulls and 122 lower jaws in lateral view, both from original photos and published pictures. Fifty-five ceratopsian species are represented in the sample.
Methods: We investigated cranial and lower jaw shape changes across ceratopsians applying two-dimensional geometric morphometrics. We also investigated the morphological variation of the snout and the frill. Using phylogenetic generalized least squares regression, we estimated the degree of phylogenetic signal in size and shape data, as well as in the shape-size relationship. We performed phenotypic evolutionary rate analysis on shape data to describe phenotypic shifts across the phylogeny. Using a rarefied version of Escoufier's RV coefficient, we tested morphological integration between skulls and lower jaws, and between snouts and frills. Finally, we explored the potential link between cranial and frill shape evolution in ceratopsians and the radiation of angiosperms using a linear regression model.
Results: Skull, snout, and frill shapes differ among clades (with the exception of leptoceratopsids and protoceratopsids). Lower jaws show distinct morphologies among groups. Size and shape changes are phylogenetically structured. The frill drives the morphological variation of the skull, co-varying much more with the lower jaw than with the snout. The frill appears to evolve to co-vary better with the lower jaw in the more morphologically derived clades than in basal ones. A significant linear relationship does exist between cranial shape and angiosperm occurrences, suggesting the hypothesis that the frill evolved in response to changes in dietary compositions associated with the turnover between gymnosperms and angiosperms during the Cretaceous. Significant negative shifts in evolutionary rates characterize skull, snout, frill, and lower jaw shapes, corresponding to nodes where psittacosaurids diverge from other taxa. In contrast, a significant positive shift in skull and snout shape rate of evolution characterizes the clade Ceratopsoidea.
Conclusion: The frill is the main driving force in the overall cranial shape within Ceratopsia and evolved secondarily to better co-vary with the lower jaw to produce a more efficient masticatory apparatus. The changes in frill shape are correlated with the angiosperm diversification that occurred in the Cretaceous and thus correlated with changes in diet. Ceratopsians exhibit a slowdown in the phenotypic evolutionary rate in the Early Cretaceous and an acceleration of the phenotypic rate in the Late Cretaceous
Applying acceptance requirements to requirements modeling tools via gamification: a case study on privacy and security.
Requirements elicitation, analysis and modeling are critical activities for software success. However, software systems are increasingly complex, harder to develop due to an ever-growing number of requirements from numerous and heterogeneous stakeholders, concerning dozens of requirements types, from functional to qualitative, including adaptation, security and privacy, ethical, acceptance and more. In such settings, requirements engineers need support concerning such increasingly complex activities, and Requirements Engineering (RE) modeling tools have been developed for this. However, such tools, although effective, are complex, time-consuming and requiring steep learning curves. The consequent lack of acceptance and abandonment in using such tools, by engineers, paves the way to the application of RE techniques in a more error-prone, low-quality way, increasing the possibility to have failures in software systems delivered. In this paper, we identify main areas of lack of acceptance, affecting RE engineers, for such tools, and propose an approach for making modeling tools more effective in engaging the engineer in performing RE in a tool-based way, receiving adequate feedback and staying motivated to use modeling tools. This is accomplished by performing acceptance requirements analysis (through the Agon Framework) and using gamification to increase the engagement of engineers during the usage of RE modeling tools. Towards this end, we performed a case study, within the VisiOn European Project, for enhancing a tool for modeling privacy and security requirements. Our case study provides preliminary evidence that our approach supports in making RE modeling tools more engaging from the engineer perspective
Stereocontrolled synthesis and functionalization of cyclobutanes and cyclobutanones
In the last decade a certain number of new cyclobutane and cyclobutanone synthesis and functionalization protocols have been published. Organo- and biocatalyzed eco-friendly approaches to cyclobutane-containing molecules have been developed with interesting results. Also, successful new total synthesis of bioactive compounds and drugs have been recently reported where a four membered ring represented the key intermediate. Therefore, the rising interest in this field represents a great point of discussion for the scientific community, disclosing the synthetic potential of strained four membered ring carbocyclic compounds. Herein we report a critical survey on the literature concerning the enantiocontrolled synthesis and functionalization of cyclobutane derivatives, with particular attention to metal-free, low impact methodologies, published during the period 2000–2013
CHARACTERIZATION OF A MOBILE MAPPING SYSTEM FOR SEAMLESS NAVIGATION
Abstract. Mobile Mapping Systems (MMS) are multi-sensor technologies based on SLAM procedure, which provides accurate 3D measurement and mapping of the environment as also trajectory estimation for autonomous navigation. The major limits of these algorithms are the navigation and mapping inconsistence over the time and the georeferencing of the products. These issues are particularly relevant for pose estimation regardless the environment like in seamless navigation. This paper is a preliminary analysis on a proposed multi-sensor platform integrated for indoor/outdoor seamless positioning system. In particular the work is devoted to analyze the performances of the MMS in term of positioning accuracy and to evaluate its improvement with the integration of GNSS and UWB technology. The results show that, if the GNSS and UWB signal are not degraded, using the correct weight to their observations in the Stencil estimation algorithm, is possible to obtain an improvement in the accuracy of the MMS navigation solution as also in the global consistency of the final point cloud. This improvement is measured in about 7 cm for planimetric coordinate and 34 cm along the elevation with respect to the use of the Stencil system alone
Smartphone-based photogrammetry for the 3D modeling of a geomorphological structure
The geomatic survey in the speleological field is one of the main activities that allows for the adding of both a scientific and popular value to cave exploration, and it is of fundamental importance for a detailed knowledge of the hypogean cavity. Today, the available instruments, such as laser scanners and metric cameras, allow us to quickly acquire data and obtain accurate three-dimensional models, but they are still expensive, require a careful planning phase of the survey, as well as some operator experience for their management. This work analyzes the performance of a smartphone device for a close-range photogrammetry approach for the extraction of accurate three-dimensional information of an underground cave. The image datasets that were acquired with a high-end smartphone were processed using the Structure from Motion (SfM)-based approach for dense point cloud generation: different image-matching algorithms implemented in a commercial and an open source software and in a smartphone application were tested. In order to assess the reachable accuracy of the proposed procedure, the achieved results were compared with a reference dense point cloud obtained with a professional camera or a terrestrial laser scanner. The approach has shown a good performance in terms of geometrical accuracies, computational time and applicability
Anatomy and phylogeny of the gavialoid crocodylian Eusuchus lerichei from the Paleogene of Europe.
Relationship between blood remifentanil concentration and stress hormone levels during pneumoperitoneum in patients undergoing laparoscopic cholecystectomy
The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectom
Arothron: an R package for virtual anthropology to build endocast and to perform digital reconstruction
Arothron is an R package [1] containing brand new tools for geometric morphometric analysis. The package comes with examples
pertaining to the field of virtual anthropology, yet it is addressed to the entire audience of geometric morphometricians. The functions
embedded in the package allow aligning disarticulated parts belonging to a single specimen (i.e. broken skull fragments), to
build internal cavities such as endocasts, and to reproduce and analyse the shapes of three-dimensional objects. Arothron functions
import and export landmark coordinates and 3D paths into ’landmarkAscii’ and ’am’ format files. The Digital Tool for Alignment
(DTA) is a landmark-based methodology which allows aligning two or more portions of a 3D mesh (i.e. a disarticulated model,
DM) by using a reference sample or model (RM) for comparison. To run DTA, a set of anatomical landmarks is defined on two
separated portions of the DM. Each point of the landmark sets is moved to the nearest vertex of the triangles. This way, each landmark
is identified by a number corresponding to a row of the vertex matrix of the mesh and its position is tracked on the 3D models
moved in the Cartesian coordinate system.The second step is the alignment via Generalized Procrustes Analysis (GPA) of each part
of the DM on each RM of the comparative sample, where the same landmark configuration as with the DM has been previously
defined. The items of the reference sample are previously scaled to the mean of the single scale factors calculated for each half of
the DM, separately, and symmetrized via reflection and relabelling, thereby producing a perfectly symmetrical, bilateral, and scaled
landmark configurations (to avoid alignment error as introduced by asymmetry). The last step consists in the quantification of the
morphological (Euclidean) distances between each part of the DM and the corresponding landmark configurations on each item in
the RM set. Computer-Aided Laser Scanner Emulator (CA-LSE) and Automatic Segmentation Tool for 3D objects (AST-3D) are
two new tools designed for the reconstruction of virtual cavities and external shapes [2]. CA-LSE provides the reconstruction of the
external portions of a 3D mesh by simulating the action of a laser scanner. AST-3D performs the digital reconstruction of anatomical
cavities as endocasts. Both tools use the definition of points of views that can be placed externally to the object (CA-LSE) or
inside the object (AST-3D). By applying these tools is possible in few minutes to build virtual cavities as endocast, maxillary sinuses
and trabecular bone. In the Arothron R package, we supplied three examples of reconstructing: the dental pulp cavity within a deciduous
Neanderthal tooth, the network of blood vessels within a human malleus bone, and an endocast of a human skull.The tools
could be used in virtual anthropology application.The digital alignment tool is efficient in find ideal alignments of broken pieces. It
could be applied as the first step in virtual reconstruction on human fossil specimens that often consist of a disarticulated fragments
such as BOU-VP12/130 (Australopithecus garhi), AL-442 (Australopithecus afarensis), OH5 (Paranthropus boisei), ATD6-15 and
ATD6-69 (Homo antecessor), Amud 1 (Homo neanderthalensis), Le Moustier 1 (Homo neanderthalensis). The easily and quickly
use of the Arothron R package to build virtual cavities may provide a new means largely applicable in virtual Anthropology.
References:[1] Profico A., Veneziano A., Melchionna M., Piras P. & Raia P., 2018. Arothron: Geometric Morphometrics Analyses. R package version 1.0.1, developer version available at
https://github/Arothron DOI:10.5281/zenodo.1218712.[2] Profico A., Schlager S., Valoriani V., Buzi C., Melchionna M., Veneziano A., Raia P., MoggifiCecchi J. & Manzi G., 2018. Reproducing the
internal and external anatomy of fossil bones: Two new automatic digital tools. American Journal of Physical Anthropology
FIRST RESULTS ON THE PRESENCE AND THE MOLECULAR CHARACTERIZATION OF ANISAKID NEMATODES IN MARINE FISH CAUGHT OFF NORTHERN SARDINIA
Anisakidosis is a parasitic zoonosis caused by nematodes of the family Anisakidae, belonging to the genera Anisakis, Contracaecum and Pseudoterranova. Molecular studies have shown that Anisakis larvae comprise a number of sibling species, which have different genetic structures, hosts and geographical distribution. A great variety of fish species can harbour infectious third stage larvae of this nematode. The preliminary results of a study carried out to evaluate the occurrence of this parasite in commercial fish caught off northern Sardinia are herein reported. From October 2008 to November 2009, 599 specimens of 8 commercial fish species were examined for anisakid larvae through visual inspection of body cavity and peptic digestion of the muscle. Isolated Anisakis sp. larvae were observed at light microscope and identified as Type I or Type II (sensu Berland, 1961). Out of 599 fish examined, 239 (40%) were infected by 1187 anisakid larvae, belonging to the genera Anisakis (1169 Type I and 18 Type II) and Hysterothylacium (692). The molecular identification of Anisakis spp. was carried out on a subsample of 30% of Type I larvae and all Type II larvae. Specimens were firstly examined using a species-specific PCR, with primers designed for Anisakis pegreffii (APEF) and Anisakis physeteris (APHF), and ITS-2 of nuclear rDNA. The results were confirmed by the analysis of the ITS region of nuclear rDNA (ITS-1, 5.8S and ITS-2) using the restriction enzymes HinfI and HhaI in PCR-RFLP. Type I larvae examined were all identified as A. pegreffii, and Type II were all A. physeteris. This is the first contribution to the epidemiology and molecular characterization of Anisakis spp. in commercial fish caught off Sardinia
Sensors integration for smartphone navigation: performances and future challenges
Nowadays the modern Smartphones include several sensors which are usually adopted in geomatic application, as digital camera, GNSS receivers, inertial platform and RFID system.
In this paper the Authors would like to testing the performances of internal sensors (IMU) of three modern smartphones (Samsung GalaxyS4, Samsung GalaxyS5 and iPhone4) compared to external mass-market IMU platform in order to verify their accuracy levels, in terms of positioning. Moreover, the Image Based Navigation (IBN) approach is also investigated: this approach can be very useful in hard-urban environment or for indoor positioning, as alternative to GNSS positioning.
IBN allows to obtain a sub-metrical accuracy, but a special database of georeferenced images (DB) is needed, moreover it is necessary to use dedicated algorithm to resizing the images which are collected by smartphone, in order to share it with the server where is stored the DB. Moreover, it is necessary to characterize smartphone camera lens in terms of focal length and lens distortions.
The Authors have developed an innovative method with respect to those available today, which has been tested in a covered area, adopting a special support where all sensors under testing have been installed. Geomatic instrument have been used to define the reference trajectory, with purpose to compare this one, with the path obtained with IBN solution. First results leads to have an horizontal and vertical accuracies better than 60 cm, respect to the reference trajectories. IBN method, sensors, test and result will be described in the paper
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