58 research outputs found

    Rogue Waves: From Nonlinear Schrödinger Breather Solutions to Sea-Keeping Test

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    Under suitable assumptions, the nonlinear dynamics of surface gravity waves can be modeled by the one-dimensional nonlinear Schrödinger equation. Besides traveling wave solutions like solitons, this model admits also breather solutions that are now considered as prototypes of rogue waves in ocean. We propose a novel technique to study the interaction between waves and ships/structures during extreme ocean conditions using such breather solutions. In particular, we discuss a state of the art sea-keeping test in a 90-meter long wave tank by creating a Peregrine breather solution hitting a scaled chemical tanker and we discuss its potential devastating effects on the ship

    Archaeogenetic analysis of Neolithic sheep from Anatolia suggests a complex demographic history since domestication

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    Sheep were among the first domesticated animals, but their demographic history is little understood. Here we analyzed nuclear polymorphism and mitochondrial data (mtDNA) from ancient central and west Anatolian sheep dating from Epipaleolithic to late Neolithic, comparatively with modern-day breeds and central Asian Neolithic/Bronze Age sheep (OBI). Analyzing ancient nuclear data, we found that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds relative to Asian breeds, a conclusion supported by mtDNA haplogroup frequencies. In contrast, OBI showed higher genetic affinity to present-day Asian breeds. These results suggest that the east-west genetic structure observed in present-day breeds had already emerged by 6000 BCE, hinting at multiple sheep domestication episodes or early wild introgression in southwest Asia. Furthermore, we found that ANS are genetically distinct from all modern breeds. Our results suggest that European and Anatolian domestic sheep gene pools have been strongly remolded since the Neolithic

    A learning analytics approach to correlate the academic achievements of students with interaction data from an educational simulator

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    This paper presents a Learning Analytics approach for understanding the learning behavior of students while interacting with Technology Enhanced Learning tools. In this work we show that it is possible to gain insight into the learning processes of students from their interaction data. We base our study on data collected through six laboratory sessions where first-year students of Computer Engineering at the University of Genoa were using a digital electronics simulator. We exploit Process Mining methods to investigate and compare the learning processes of students. For this purpose, we measure the understandability of their process models through a complexity metric. Then we compare the various clusters of students based on their academic achievements. The results show that the measured complexity has positive correlation with the final grades of students and negative correlation with the difficulty of the laboratory sessions. Consequently, complexity of process models can be used as an indicator of variations of student learning paths

    The Neuropeptide Y Y1 receptor: a diagnostic marker? Expression in MCF-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts

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    The neuropeptide Y (NPY) Y1 receptor (Y1R) has been suggested as a tumor marker for in vivo imaging and as a therapeutic target. In view of the assumed link between estrogen receptor (ER) and Y1R in mammary carcinoma and with respect to the development of new diagnostic tools we investigated the Y1R protein expression in human MCF-7 cell variants differing in ER content and sensitivity against antiestrogens. ER and Y1R expression were quantified by radioligand binding using [3H]-17beta-estradiol and the Y1R selective antagonist [3H]-UR-MK114, respectively. The latter was used for cellular binding studies and for autoradiography of MCF-7 xenografts. The fluorescent ligands Cy5-pNPY (universal Y1R, Y2R and Y5R agonist) and UR-MK22 (selective Y1R antagonist), as well as the selective antagonists BIBP3226 (Y1R), BIIE0246 (Y2R) and CGP71683 (Y5R) were used to identify the NPY receptor subtype(s) by confocal microscopy. Y1R functionality was determined by mobilization of intracellular Ca2+. Sensitivity of MCF-7 cells against antiestrogen 4-hydroxytamoxifen correlated directly with the ER content. The exclusive expression of Y1Rs was confirmed by confocal microscopy. The Y1R protein was up-regulated (100 %) by 17beta-estradiol (EC50 20 pM) and the predominant role of ERalpha was demonstrated by using the ERalpha-selective agonist “propylpyrazole triol”. 17beta-Estradiol-induced over-expression of functional Y1R protein was reverted by the antiestrogen fulvestrant (IC50 5 nM) in vitro. Furthermore, tamoxifen treatment of nude mice resulted in an almost total loss of Y1Rs in MCF-7 xenografts. In conclusion, the value of the Y1R as a target for therapy and imaging in breast cancer patients may be compromised due to Y1R down-regulation induced by hormonal (antiestrogen) treatment

    Linear-Complexity Private Function Evaluation is Practical

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    Private function evaluation (PFE) allows to obliviously evaluate a private function on private inputs. PFE has several applications such as privacy-preserving credit checking and user-specific insurance tariffs. Recently, PFE protocols based on universal circuits (UCs), that have an inevitable superlinear overhead, have been investigated thoroughly. Specialized public key-based protocols with linear complexity were believed to be less efficient than UC-based approaches. In this paper, we take another look at the linear-complexity PFE protocol by Katz and Malka (ASIACRYPT\u2711): We propose several optimizations and split the protocol in different phases that depend on the function and inputs respectively. We show that HE-based PFE is practical when instantiated with state-of-the-art ECC and RLWE-based homomorphic encryption. Our most efficient implementation outperforms the most recent UC-based PFE implementation of Alhassan et al. (JoC\u2720) in communication for all circuit sizes and in computation starting from circuits of a few thousand gates already
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