2,402 research outputs found
Calcifying odontogenic cyst associated with compound odontoma: A study on undemineralized material
In a minority of cases of calcifying odontogenic cyst (COC) it is possible to observe the formation of dental hard tissues in the cyst wall. The use of undemineralized sections has allowed an evaluation of the mineralized tissues normally lost with the use of demineralizing agents. All the dental hard tissues presented a high degree of morpho- and histodifferentiation. The histochemical staining for calcium salts (von Kossa) showed the presence of areas of low mineralization in the portion of the lesion, where the tissue maturation was not complete. In conclusion the appearance of the dental hard tissues in this case of compound odontoma arising in the cyst wall of a COC is similar to that already described in compound odontoma not associated with COC.Il est possible dâobserver la formation de tissus dentaires durs dans la paroi dâune minoritĂ© de cas de kystes odontogĂšnes calcifiants (KOC). Lâutilisation de coupes de tissus non dĂ©minĂ©ralisĂ©s a permis une Ă©valuation des tissus minĂ©ralisĂ©s qui sont habituellement perdus aprĂšs dĂ©calcification. Tous les tissus dentaires durs prĂ©sentent un degrĂ© important de morpho- en dâhistodiffĂ©renciation. La coloration histochimique des sels calcaires (von Kossa) montre la prĂ©sence de territoires de faible minĂ©ralisation dans les rĂ©gions dans lesquelles la maturation tissulaire est incomplĂšte.En conclusion, lâapparence des tissus dentaires durs dans ce cas dâodontome composĂ© dĂ©veloppĂ© dans la paroi dâun kyste odontogĂšne calcifiĂ© est semblable Ă celle dĂ©jĂ dĂ©crite dans les odontomes composĂ©s non associĂ© Ă un KOC
Looking at flavonoid biodiversity in horticultural crops: A colored mine with nutritional benefits
Flavonoids represent a wide group of plant secondary metabolites implicated in many physiological roles, from the attraction of pollinators to the protection against biotic or abiotic stresses. Flavonoids are synthetized in a number of horticultural crops that are important components of our daily diet. In the last decades, the consumption of vegetables rich in antioxidants has been strongly promoted from the perspective of prevention/protection against chronic diseases. Therefore, due to their nutritional importance, several attempts have been made to enhance flavonoid levels in species of agronomic interest. In this review, we focus on the flavonoid biodiversity among the major horticultural species, which is responsible of differences among closely related species and influences the qualitative/quantitative composition. We also review the role of flavonoids in the nutritional quality of plant products, contributing to their organoleptic and nutritional properties, and the main strategies of biofortification to increase their content
A possible solution of the puzzling variation of the orbital period of MXB 1659-298
MXB 1659-298 is a transient neutron star Low-Mass X-ray binary system that
shows eclipses with a periodicity of 7.1 hr. The source went to outburst in
August 2015 after 14 years of quiescence. We investigate the orbital properties
of this source with a baseline of 40 years obtained combining the eight eclipse
arrival times present in literature with 51 eclipse arrival times collected
during the last two outbursts. A quadratic ephemeris does not fit the delays
associated with the eclipse arrival times and the addition of a sinusoidal term
with a period of yr is required. We infer a binary orbital
period of hr and an orbital period derivative of
s s. We show that the large orbital
period derivative can be explained with a highly non conservative mass transfer
scenario in which more than 98\% of the mass provided by the companion star
leaves the binary system. We predict an orbital period derivative value of
s s and constrain the companion star
mass between 0.3 and M. Assuming that the
companion star is in thermal equilibrium the periodic modulation can be due to
either a gravitational quadrupole coupling due to variations of the oblateness
of the companion star or with the presence of a third body of mass M
Jovian masses.Comment: 10 pages, 6 figures. Accepted by MNRA
Bimodal chemical evolution of the Galactic disk and the Barium abundance of Cepheids
In order to understand the Barium abundance distribution in the Galactic disk
based on Cepheids, one must first be aware of important effects of the
corotation resonance, situated a little beyond the solar orbit. The thin disk
of the Galaxy is divided in two regions that are separated by a barrier
situated at that radius. Since the gas cannot get across that barrier, the
chemical evolution is independent on the two sides of it. The barrier is caused
by the opposite directions of flows of gas, on the two sides, in addition to a
Cassini-like ring void of HI (caused itself by the flows). A step in the
metallicity gradient developed at corotation, due to the difference in the
average star formation rate on the two sides, and to this lack of communication
between them. In connection with this, a proof that the spiral arms of our
Galaxy are long-lived (a few billion years) is the existence of this step. When
one studies the abundance gradients by means of stars which span a range of
ages, like the Cepheids, one has to take into account that stars, contrary to
the gas, have the possibility of crossing the corotation barrier. A few stars
born on the high metallicity side are seen on the low metallicity one, and
vice-versa. In the present work we re-discuss the data on Barium abundance in
Cepheids as a function of Galactic radius, taking into account the scenario
described above. The [Ba/H] ratio, plotted as a function of Galactic radius,
apparently presents a distribution with two branches in the external region
(beyond corotation). One can re-interpret the data and attribute the upper
branch to the stars that were born on the high metallicity side. The lower
branch, analyzed separately, indicates that the stars born beyond corotation
have a rising Barium metallicity as a function of Galactic radius.Comment: 6 pages, 7 figures, Proceedings of IAU Symposium 29
The impact of COVID-19 on the scientific production spread: A five-month bibliometric report of the worldwide research community
Introduction: The recent COVID-19 pandemic has gained recently a deep increasing of research interest in all fields of the human knowledge due to prevention of the Sars-Cov-2 infection and disease treatment The present investigation evaluated the topic publications and the citation network analysis during the early phases of COVID-19 pandemic spread. Methods: the Boolean search was performed according to the Pubmed Mesh terms by by Scopus Elsevier database. The papers, co-authors, number of citations obtained and scientific journals were recorded. Results: a total of 164 scientific journals were assessed in the present research with a mean impact factor value of 4.612±8.705 (range: 70.67-0; median: 2,687, Q1: 0,701; Q3: 4,928). Conclusions: The studies selected showed The bibliometric research showed an early representation of the research orientation of the research activity about COVID 19. The most represented scientific fields concerned with healthcare and medicine, while for the social and economic fields are gaining interests due to the pandemic spread
Econometric and Machine Learning Methods to Identify Pedestrian Crash Patterns
Walking plays an important role in overcoming many challenges nowadays, and governments and local authorities are encouraging healthy and environmentally sustainable lifestyles. Nevertheless, pedestrians are the most vulnerable road users and crashes with pedestrian involvement are a serious concern. Thus, the identification of pedestrian crash patterns is crucial to identify appropriate safety countermeasures. The aims of the study are (1) to identify the road infrastructure, environmental, vehicle, and driver-related patterns that are associated with an overrepresentation of pedestrian crashes, and (2) to identify safety countermeasures to mitigate the detected pedestrian crash patterns. The analysis carried out an econometric model, namely the mixed logit model, and the association rules and the classification tree algorithm, as machine learning tools, to analyse the patterns contributing to the overrepresentation of pedestrian crashes in Italy. The dataset consists of 874,847 crashesâincluding 101,032 pedestrian crashesâthat occurred in Italy from 2014 to 2018. The methodological approach adopted in the study was effective in uncovering relations among road infrastructure, environmental, vehicle, and driver-related patterns, and the overrepresentation of pedestrian crashes. The mixed logit provided a clue on the impact of each pattern on the pedestrian crash occurrence, whereas the association rules and the classification tree detected the associations among the patterns with insights on how the co-occurrence of more factors could be detrimental to pedestrian safety. Driversâ behaviour and psychophysical state turned out to be crucial patterns related to pedestrian crashesâ overrepresentation. Based on the identified crash patterns, safety countermeasures have been proposed
Attack-Surface Metrics, OSSTMM and Common Criteria Based Approach to âComposable Securityâ in Complex Systems
In recent studies on Complex Systems and Systems-of-Systems theory, a huge effort has been put to cope with behavioral problems, i.e. the possibility of controlling a desired overall or end-to-end behavior by acting on the individual elements that constitute the system itself. This problem is particularly important in the âSMARTâ environments, where the huge number of devices, their significant computational capabilities as well as their tight interconnection produce a complex architecture for which it is difficult to predict (and control) a desired behavior; furthermore, if the scenario is allowed to dynamically evolve through the modification of both topology and subsystems composition, then the control problem becomes a real challenge. In this perspective, the purpose of this paper is to cope with a specific class of control problems in complex systems, the âcomposability of security functionalitiesâ, recently introduced by the European Funded research through the pSHIELD and nSHIELD projects (ARTEMIS-JU programme). In a nutshell, the objective of this research is to define a control framework that, given a target security level for a specific application scenario, is able to i) discover the system elements, ii) quantify the security level of each element as well as its contribution to the security of the overall system, and iii) compute the control action to be applied on such elements to reach the security target. The main innovations proposed by the authors are: i) the definition of a comprehensive methodology to quantify the security of a generic system independently from the technology and the environment and ii) the integration of the derived metrics into a closed-loop scheme that allows real-time control of the system. The solution described in this work moves from the proof-of-concepts performed in the early phase of the pSHIELD research and enrich es it through an innovative metric with a sound foundation, able to potentially cope with any kind of pplication scenarios (railways, automotive, manufacturing, ...)
On the Effect of Channel Knowledge in Underwater Acoustic Communications: Estimation, Prediction and Protocol
Underwater acoustic communications are limited by the following channel impairments: time variability, narrow bandwidth, multipath, frequency selective fading and the Doppler effect. Orthogonal Frequency Division Modulation (OFDM) is recognized as an effective solution to such impairments, especially when optimally designed according to the propagation conditions. On the other hand, OFDM implementation requires accurate channel knowledge atboth transmitter and receiver sides. Long propagation delay may lead to outdated channel information. In this work, we present an adaptive OFDM scheme where channel state information is predicted through a Kalman-like filter so as to optimize communication parameters, including the cyclic prefix length. This mechanism aims to mitigate the variability of channel delay spread. This is cast in a protocol where channel estimation/prediction are jointly considered, so as to allow efficiency. The performance obtained through extensive simulations using real channels and interference show the effectiveness of the proposed scheme, both in terms of rate and reliability, at the expense of an increasing complexity. However, this solution is significantly preferable to the conventional mechanism, where channel estimation is performed only at the receiver, with channel coefficients sent back to the transmit node by means of frequent overhead signaling
Blind fractionally spaced channel equalization for shallow water PPM digital communications links
Underwater acoustic digital communications suffer from inter-symbol interference deriving from signal distortions caused by the channel propagation. Facing such kind of impairment becomes particularly challenging when dealing with shallow water scenarios characterized by short channel coherence time and large delay spread caused by time-varying multipath effects. Channel equalization operated on the received signal represents a crucial issue in order to mitigate the effect of inter-symbol interference and improve the link reliability. In this direction, this contribution presents a preliminary performance analysis of acoustic digital links adopting pulse position modulation in severe multipath scenarios. First, we show how the spectral redundancy offered by pulse position modulated signals can be fruitfully exploited when using fractional sampling at the receiver side, which is an interesting approach rarely addressed by the current literature. In this context, a novel blind equalization scheme is devised. Specifically, the equalizer is blindly designed according to a suitably modified Bussgang scheme in which the zero-memory nonlinearity is replaced by a M-memory nonlinearity, M being the pulse position modulation order. Numerical results not only confirm the feasibility of the technique described here, but also assess the quality of its performance. An extension to a very interesting complex case is also provided
Which is the most accurate diagnostic procedure in Tamoxifen treated breast cancer patients
Purpose: The aim of this study was to evaluate the diagnostic accuracy of bi-dimensional (2D) and three-dimensional (3D) transvaginal ultrasound (TVUS), hysterosonography (HSSG) and hysteroscopy in the detection of endometrial pathology in women treated with tamoxifen (TMX) for breast cancer.
Methods: Forty-two patients, affected by breast cancer under treatment with TMX, underwent 2D-3D TVUS, HSSG and hysteroscopy completed by biopsy, after abnormal findings following a routine 2D TVUS examination.
Results: 3D-TVUS was more accurate than 2D-TVUS in the detection of atrophic endometrium confirmed by biopsy and in the detection of endometrial polyps.
HSSG and hysteroscopy detected atrophic endometrium and endometrial polyps significantly better than ultrasound scan. Endometrial carcinoma was detected in two cases, and in both HSSG and hysteroscopy were 100% diagnostic.
Conclusion: In TMX treated breast cancer patients, HSSG and hysteroscopy provide more accurate diagnosis than 2D-3D ultrasound in the detection of treatment related endometrial lesions
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