Lazy localization using the Frozen-Time Smoother

We present a new algorithm for solving the global localization problem called Frozen-Time Smoother (FTS). Time is 'frozen', in the sense that the belief always refers to the same time instant, instead of following a moving target, like Monte Carlo Localization does. This algorithm works in the case in which global localization is formulated as a smoothing problem, and a precise estimate of the incremental motion of the robot is usually available. These assumptions correspond to the case when global localization is used to solve the loop closing problem in SLAM. We compare FTS to two Monte Carlo methods designed with the same assumptions. The experiments suggest that a naive implementation of the FTS is more efficient than an extremely optimized equivalent Monte Carlo solution. Moreover, the FTS has an intrinsic laziness: it does not need frequent updates (scans can be integrated once every many meters) and it can process data in arbitrary order. The source code and datasets are available for download

A Bayesian framework for optimal motion planning with uncertainty

Modeling robot motion planning with uncertainty in a Bayesian framework leads to a computationally intractable stochastic control problem. We seek hypotheses that can justify a separate implementation of control, localization and planning. In the end, we reduce the stochastic control problem to path- planning in the extended space of poses x covariances; the transitions between states are modeled through the use of the Fisher information matrix. In this framework, we consider two problems: minimizing the execution time, and minimizing the final covariance, with an upper bound on the execution time. Two correct and complete algorithms are presented. The first is the direct extension of classical graph-search algorithms in the extended space. The second one is a back-projection algorithm: uncertainty constraints are propagated backward from the goal towards the start state

Coordination of passive systems under quantized measurements

In this paper we investigate a passivity approach to collective coordination and synchronization problems in the presence of quantized measurements and show that coordination tasks can be achieved in a practical sense for a large class of passive systems.Comment: 40 pages, 1 figure, submitted to journal, second round of revie

Role of traditional and new biomarkers in breast carcinogenesis

In recent decades, several biomarkers have been investigated as predictors of breast cancer risk, development, prognosis and treatment efficacy

A review of carbonatitic magmatism in the Paraná-Angola-Namibia (PAN) system.

Mesozoic to Cenozoic alkaline-carbonatitic complexes from southern Brazil, Angola and Namibia occur along main tectonic lineaments. In general, the alkaline-carbonatite complexes show intrusive/subintrusive, subcircular or oval shaped structures and are indicative of high upwelling energy. Processes of liquid immiscibility from trachytic-phonolitic liquids, starting from parental alkaline mafic magmas are believed to have generated carbonatitic liquids, as suggested by field relationships and geochemical characteristics. Ca-, Mg- and Fe-carbonatites are widespread even in the same complex. The occurrences comprise three main chronogroups, i.e. 1) Early Cretaceous (Eastern Paraguay; Brazil, Ponta Grossa Arch and Anitapolis; Angola and Namibia); 2) Late Cretaceous (Brazil , Ponta Grossa Arch, Lages and Alto Paranaiba. Namibia); 3) Paleogene, Brazil and Namibia Two principal types of associated alkaline rocks are represented, i.e. plagioleucitites l.s. (Eastern Paraguay; Brazil: Ponta Grossa Arch- Angola and Namibia) and kamafugites l.s. (Brazil: alto Paranaiba and Lages; Namibia). Significant variations in O-C isotope compositions are found in primary carbonates , the variations being mainly due to isotope exchange between carbonates and H2O-CO2-rich hydrothermal fluids, whereas magmatic processes, i.e. fractional crystallization or liquid immiscibility, probably affect the delta O-18 and delta C-13 values by not more than 2 delta%.. The isotope exchange model implies that the most significant isotopic variations took place in a hydrothermal environment, e.g. in the range 400-80 degrees C, involving fluids with CO2/H2O ratio ranging from 0.8 to 1. Sr-Nd-Pb isotope systematics highlight heterogeneous mixtures between HIMU and EMI mantle components, similar to the associated alkaline rocks and the flood tholeiites of the Parana-Angola-Etendeka (Namibia) system. This is also consistent with Re-Os systematics on selected mafic samples from the Alto Paranaiba alkaline-carbonatite province. The data relative to the noble gases suggest that the source(s) are similar to other mantle derived magmas (e.g. HIMU and MORB) and that the carbon of carbonatites is unlikely to be subduction-related carbon, and support a C-O fractionation model starting from mantle-derived sources. In spite of the strong variation shown by C-O isotopes, Sr-Nd-Pb-Os isotopic systematics could be related to an isotopically enriched source where the chemical heterogeneities reflect a depleted mantle "metasomatized" by small-volume melts and fluids rich in incompatible elements. These fluids are expected to have promoted crystallization in the mantle of K-rich phases that gave rise to a veined network variously enriched in LILE and LREE (cf. Foley, 1992b). The newly formed veins (enriched component) and peridotite matrix (depleted component) underwent a different isotopic evolution with time as reflected by the carbonatitic rocks. These conclusions may be extended to the whole Parana-Angola-Etendeka system, where isotopically distinct parent magmas were generated following two main enrichment events of the subcontinental lithospheric mantle at 2.0-1.4 and 1.0-0.5 Ga, respectively, as also supported by Re-Os systematics. The mantle sources preserved the isotopic heterogeneities over a long time, suggesting a non-convective lithospheric mantle beneath different cratons or intercratonic regions. Overall the data indicate that the alkaline-carbonatitic magmatism originated from a significant, but small scale heterogeneous subcontinental mantle. In this scenario, the Tristan da Cunha, Walvis Ridge-Rio Grande Rise and Vitoria-Trindade hotspot tracks might reflect the accomodation of stresses in the lithosphere during rifting, rather than continuous magmatic activity induced by mantle plumes beneath the moving lithosphere

Lo stato dell’ambiente marino nell’area del Canale di Sicilia in prossimità del SIN di Gela.

Viene illustrata in questa nota l’attuale condizione in cui si trova lo stato dell’ambiente marino nell’area del Canale di Sicilia immediatamente a ridosso della costa merdionale delle Sicilia dal Golfo di Gela alla costa iblea. Lo stato dell’ambiente in oggetto viene valutato in base alla distribuzione di alcuni metalli in tracce normalmente ritenuti fra i più significativi per gli scopi prefissati, esaminati lungo la colonna d’acqua e nei sedimenti superficiali di fondale. I risultati ottenuti, illustrati anche attraverso un’indagine statistica multivariata, indicano un arricchimento superficiale della colonna d’acqua in lantanio che può essere ascritto tanto ad un’origine litogenica, quanto ad input antropico. Nei sedimenti al naturale raggruppamento fra elementi in tracce in tracce basato su analogie comportamentali di carattere geochimica sfugge il Ni che mostra di provenire da una fonte differente per la quale non si può escludere la natura antropica. Tale ipotesi di esiti di antropizzazione trova conforto nei raffronti condotti con il chimismo del particolato atmosferico desunto da dati di letteratura

Changing dietary habits in veneto region over two decades: Still a long road to go to reach an iodine-sufficient status

Background: Fifteen years after a nationwide voluntary iodine prophylaxis program was introduced, the aims of the present study were: (a) to obtain an up-to-date assessment of dietary iodine intake in the Veneto region, Italy; and (b) to assess dietary and socioeconomic factors that might influence iodine status. Methods: Urinary iodine concentration (UIC) was obtained in 747 school students (median age 13 years; range: 11–16 years). Results: The median UIC was 111 _g/L, with 56% of samples _ 100 _g/L, but 26% were < 50 _g/L, more frequently females. Iodized salt was used by 82% of the students. The median UIC was higher among users of iodized salt than among non-users, 117.0 ug/L versus 90 ug/L (p = 0.01). The median UIC was higher in regular consumers of cow’s milk than in occasional consumers, 132.0 _g/L versus 96.0 _g/L (p < 0.01). A regular intake of milk and/or the use of iodized salt su_ced to reach an adequate median UIC, although satisfying only with the combined use. A trend towards higher UIC values emerged in regular consumers of cheese and yogurt. Conclusion: Iodine status has improved (median UIC 111.0 _g/L), but it is still not adequate as 26% had a UIC < 50 _g/L in the resident population of the Veneto region. A more widespread use of iodized salt but also milk and milk product consumption may have been one of the key factors in achieving this partial improvement

Colorimetric Test for Fast Detection of SARS-CoV-2 in Nasal and Throat Swabs

Mass testing is fundamental to face the pandemic caused by the coronavirus SARS-CoV-2 discovered at the end of 2019. To this aim, it is necessary to establish reliable, fast, and cheap tools to detect viral particles in biological material so to identify the people capable of spreading the infection. We demonstrate that a colorimetric biosensor based on gold nanoparticle (AuNP) interaction induced by SARS-CoV-2 lends itself as an outstanding tool for detecting viral particles in nasal and throat swabs. The extinction spectrum of a colloidal solution of multiple viral-target gold nanoparticles-AuNPs functionalized with antibodies targeting three surface proteins of SARS-CoV-2 (spike, envelope, and membrane)-is red-shifted in few minutes when mixed with a solution containing the viral particle. The optical density of the mixed solution measured at 560 nm was compared to the threshold cycle (Ct) of a real-time PCR (gold standard for detecting the presence of viruses) finding that the colorimetric method is able to detect very low viral load with a detection limit approaching that of the real-time PCR. Since the method is sensitive to the infecting viral particle rather than to its RNA, the achievements reported here open a new perspective not only in the context of the current and possible future pandemics, but also in microbiology, as the biosensor proves itself to be a powerful though simple tool for measuring the viral particle concentration