146 research outputs found

    SUBSTITUTIONAL MODEL OF THE SOIL BASED ON ARTIFICAL NEURAL NETWORKS

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    U radu je prikazana interpretacija rezultata mjerenja specifičnog otpora tla primjenom umjetnih neuronskih mreža. Model zasnovan na umjetnim neuronskim mrežama nadomješta tlo koje se fizikalno može smatrati kao dvoslojni medij s vertikalnom promjenom specifičnog električnog otpora i s vodoravnom granicom među slojevima. Učenje umjetne neuronske mreže provedeno je pod nadzorom sa skupom ulaznih podataka koji su dobiveni na temelju vrlo točnog teorijskog modela dvoslojnog tla. Predloženi algoritam; koji aproksimira nelinearne karakteristike tla koristeći umjetne neuronske mreže; pouzdano procjenjuje parametre tla i specifičnu električnu otpornost tla. Primjena nadomjesnog modela tla zasnovanog na neuronskim mrežama prikazana je na praktičnom primjeru određivanja parametara dvoslojnog tla iz mjernih podataka dobivenih Wennerovom tehnikom mjerenja specifičnog otpora tla. Radi jednostavnosti izlaganja i usporedivosti modela strujne sonde (štapovi) su nadomještene kuglastim elektrodama; odnosno točkastim izvorima polja. Dobiveni rezultati su prikazani analitički i grafički te diskutirani.This paper presents an interpretation of the results of measurement of specific soil resistivity by means of artificial neural networks.The model based on artificial neural networks replaces the soil which can be physically considered a two-layer medium with a vertical change of the specific electric resistivity and a horizontal boundary line between the layers. Learning of the neural network was performed under supervision using the input dataset obtained by means of a very accurate theoretical model of the double-layer soil. The proposed algorithm that approximates non-linear soil properties using the artificial neural network is reliable in assessment of the soil parameters and specific electric soil resistivity. Application of the substitutional model of the soil based on neural networks is demonstrated by a realistic example; determination of parameters of the double-layer soil from the measured data obtained by the Wenner technique for measuring the specific soil resistivity. For simplicity of presentation and model comparability; the current probes (poles) are replaced by the ball electrodes; i.e. spot field sources. The results obtained are analytically and graphically presented and discussed

    Consensus recommendations for the diagnosis, treatment and follow-up of inherited methylation disorders

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    Inherited methylation disorders are a group of rarely reported, probably largely underdiagnosed disorders affecting transmethylation processes in the metabolic pathway between methionine and homocysteine. These are methionine adenosyltransferase I/III, glycine N-methyltransferase, S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies. This paper provides the first consensus recommendations for the diagnosis and management of methylation disorders. Following search of the literature and evaluation according to the SIGN-methodology of all reported patients with methylation defects, graded recommendations are provided in a structured way comprising diagnosis (clinical presentation, biochemical abnormalities, differential diagnosis, newborn screening, prenatal diagnosis), therapy and follow-up. Methylation disorders predominantly affect the liver, central nervous system and muscles, but clinical presentation can vary considerably between and within disorders. Although isolated hypermethioninemia is the biochemical hallmark of this group of disorders, it is not always present, especially in early infancy. Plasma S-adenosylmethionine and S-adenosylhomocysteine are key metabolites for the biochemical clarification of isolated hypermethioninemia. Mild hyperhomocysteinemia can be present in all methylation disorders. Methylation disorders do not qualify as primary targets of newborn screening. A low-methionine diet can be beneficial in patients with methionine adenosyltransferase I/III deficiency if plasma methionine concentrations exceed 800 μmol/L. There is some evidence that this diet may also be beneficial in patients with S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies. S-adenosylmethionine supplementation may be useful in patients with methionine adenosyltransferase I/III deficiency. Recommendations given in this article are based on general principles and in practice should be adjusted individually according to patient's age, severity of the disease, clinical and laboratory findings

    Reproductive Performance of Late Pregnant Gilts Treated with Baypamun© before Farrowing

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    The aim of this study was to investigate whether the production results of pregnant gilts, grown under commercial farm conditions and moved from the sow keeping unit to the prefarrowing unit, could be increased by non-specific immunization with Baypamun© (Bayer, Leverkusen, Germany; BPM), an immune response modifier (IRM). We used three groups of pregnant gilts that obtained different treatments. Non-treated group A served as control; two experimental groups were treated on Day 6, 4 and 2 (group B), or on Day 5, 3 and 1 (group C), respectively, before their transfer from the sow keeping unit to the prefarrowing unit. The experimental gilts received i.m. 2 ml of IRM BPM, i.e. inactivated Parapoxovis virus (1 x 106.75 TCID50). Throughout the trial, the numbers of liveborn and stillborn piglets and the duration of farrowing were recorded. Variance analysis with the type of treatment as independent variable showed a significant difference between control (group A) and experimental group B in the number of liveborn piglets (P < 0.0001) as well as between group A and group B (P < 0.0001) or group C (P < 0.0001) in the number of stillborn piglets, respectively. No differences in duration of farrowing between groups were recorded

    S-Adenosylhomocysteine hydrolase deficiency in a 26-year-old man

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    This paper reports the third proven human case of deficient S-adenosylhomocysteine (AdoHcy) hydrolase activity. The patient is similar to the only two previously reported cases with this disorder in having severe myopathy, developmental delay, elevated serum creatine kinase (CK) concentrations, and hypermethioninaemia. Although he has been followed from infancy, the basic enzyme deficiency was established only at age 26 years. The diagnosis was based on markedly elevated plasma concentrations of both AdoHcy and S-adenosylmethionine, some 20% of the mean control activity of AdoHcy hydrolase activity in haemolysates of his red-blood cells, and two missense mutations in his gene encoding AdoHcy hydrolase. He had low values of erythrocyte phosphatidylcholine and plasma free choline and marginally elevated excretion of guanidinoacetate, suggesting that the elevated AdoHcy may have been inhibiting methylation of phosphatidylethanolamine and guanidinoacetate. His leukocyte DNA was globally more methylated than the DNA's of his parents or the mean extent of methylation measured in age-matched control subjects

    Compressed σ-protocol theory and practical application to plug & play secure algorithmics

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    Σ-Protocols provide a well-understood basis for secure algorithmics. Recently, Bulletproofs (Bootle et al., EUROCRYPT 2016, and Bünz et al., S&P 2018) have been proposed as a drop-in replacement in case of zero-knowledge (ZK) for arithmetic circuits, achieving logarithmic communication instead of linear. Its pivot is an ingenious, logarithmic-size proof of knowledge BP for certain quadratic relations. However, reducing ZK for general relations to it forces a somewhat cumbersome “reinvention” of cryptographic protocol theory. We take a rather different viewpoint and reconcile Bulletproofs with Σ-Protocol Theory such that (a) simpler circuit ZK is developed within established theory, while (b) achieving exactly the same logarithmic communication. The natural key here is linearization. First, we repurpose BPs as a blackbox compression mechanism for standard Σ-Protocols handling ZK proofs of general linear relations (on compactly committed secret vectors); our pivot. Second, we reduce the case of general nonlinear relations to blackbox applications of our pivot via a novel variation on arithmetic secret sharing based techniques for Σ-Protocols (Cramer et al., ICITS 2012). Orthogonally, we enhance versatility by enabling scenarios not previously addressed, e.g., when a secret input is dispersed across several commitments. Standard implementation platforms leading to logarithmic communication follow from a Discrete-Log assumption or a generalized Strong-RSA assumption. Also, under a Knowledge-of-Exponent Assumption (KEA) communication drops to constant, as in ZK-SNARKS. All in all, our theory should more generally be useful for modular (“plug & play”) design of practical cryptographic protocols; this is further evidenced by our separate work (2020) on proofs of partial knowledge

    Universally Composable Accumulators

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    Accumulators, first introduced by Benaloh and de Mare (Eurocrypt 1993), are compact representations of arbitrarily large sets and can be used to prove claims of membership or non-membership about the underlying set. They are almost exclusively used as building blocks in real-world complex systems, including anonymous credentials, group signatures and, more recently, anonymous cryptocurrencies. Having rigorous security analysis for such systems is crucial for their adoption and safe use in the real world, but it can turn out to be extremely challenging given their complexity. In this work, we provide the first universally composable (UC) treatment of cryptographic accumulators. There are many different types of accumulators: some support additions, some support deletions and some support both; and, orthogonally, some support proofs of membership, some support proofs of non-membership, and some support both. Additionally, some accumulators support public verifiability of set operations, and some do not. Our UC definition covers all of these types of accumulators concisely in a single functionality, and captures the two basic security properties of accumulators: correctness and soundness. We then prove the equivalence of our UC definition to standard accumulator definitions. This implies that existing popular accumulator schemes, such as the RSA accumulator, already meet our UC definition, and that the security proofs of existing systems that leverage such accumulators can be significantly simplified. Finally, we use our UC definition to get simple proofs of security. We build an accumulator in a modular way out of two weaker accumulators (in the style of Baldimtsi et. al (Euro S&P 2017), and we give a simple proof of its UC security. We also show how to simplify the proofs of security of complex systems such as anonymous credentials. Specifically, we show how to extend an anonymous credential system to support revocation by utilizing our results on UC accumulators

    Examining the validity of the Athlete Engagement Questionnaire (AEQ) within a Portuguese sport setting

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    Sport psychology literature suggests that understanding engagement levels is pivotal to promote positive sporting experiences among athletes. The purpose of this study was to examine the psychometric properties of the Athlete Engagement Questionnaire among Portuguese sport athletes. Two distinct samples of Portuguese athletes from different competitive levels were collected, and the results of a confirmatory factor analysis demonstrated a good fit of the model to the data. A review of the psychometric properties indicated that all factors showed good composite reliability, convergent validity, and discriminant validity. In addition, a multi-groups analysis showed the invariance of the model in two independent samples providing evidence of cross validity. Implications of these results for scholars and coaches are discussed and guidelines for future studies are suggested

    Incrementally Aggregatable Vector Commitments and Applications to Verifiable Decentralized Storage

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    Vector commitments with subvector openings (SVC) [Lai-Malavolta, Boneh-Bunz-Fisch; CRYPTO\u2719] allow one to open a committed vector at a set of positions with an opening of size independent of both the vector\u27s length and the number of opened positions. We continue the study of SVC with two goals in mind: improving their efficiency and making them more suitable to decentralized settings. We address both problems by proposing a new notion for VC that we call incremental aggregation and that allows one to merge openings in a succinct way an unbounded number of times. We show two applications of this property. The first one is immediate and is a method to generate openings in a distributed way. For the second one, we use incremental aggregation to design an algorithm for faster generation of openings via preprocessing. We then proceed to realize SVC with incremental aggregation. We provide two constructions in groups of unknown order that, similarly to that of Boneh et al. (which supports only one-hop aggregation), have constant-size public parameters, commitments and openings. As an additional feature, for the first construction we propose efficient arguments of knowledge of subvector openings which immediately yields a keyless proof of storage with compact proofs. Finally, we address a problem closely related to that of SVC: storing a file efficiently in completely decentralized networks. We introduce and construct verifiable decentralized storage (VDS), a cryptographic primitive that allows to check the integrity of a file stored by a network of nodes in a distributed and decentralized way. Our VDS constructions rely on our new vector commitment techniques

    Genotype–phenotype correlation in contactin-associated protein-like 2 (CNTNAP-2) developmental disorder

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    Contactin-associated protein-like 2 (CNTNAP2) gene encodes for CASPR2, a presynaptic type 1 transmembrane protein, involved in cell–cell adhesion and synaptic interactions. Biallelic CNTNAP2 loss has been associated with “Pitt-Hopkins-like syndrome-1” (MIM#610042), while the pathogenic role of heterozygous variants remains controversial. We report 22 novel patients harboring mono- (n = 2) and bi-allelic (n = 20) CNTNAP2 variants and carried out a literature review to characterize the genotype–phenotype correlation. Patients (M:F 14:8) were aged between 3 and 19 years and affected by global developmental delay (GDD) (n = 21), moderate to profound intellectual disability (n = 17) and epilepsy (n = 21). Seizures mainly started in the first two years of life (median 22.5 months). Antiseizure medications were successful in controlling the seizures in about two-thirds of the patients. Autism spectrum disorder (ASD) and/or other neuropsychiatric comorbidities were present in nine patients (40.9%). Nonspecific midline brain anomalies were noted in most patients while focal signal abnormalities in the temporal lobes were noted in three subjects. Genotype–phenotype correlation was performed by also including 50 previously published patients (15 mono- and 35 bi-allelic variants). Overall, GDD (p < 0.0001), epilepsy (p < 0.0001), hyporeflexia (p = 0.012), ASD (p = 0.009), language impairment (p = 0.020) and severe cognitive impairment (p = 0.031) were significantly associated with the presence of biallelic versus monoallelic variants. We have defined the main features associated with biallelic CNTNAP2 variants, as severe cognitive impairment, epilepsy and behavioral abnormalities. We propose CASPR2-deficiency neurodevelopmental disorder as an exclusively recessive disease while the contribution of heterozygous variants is less likely to follow an autosomal dominant inheritance pattern
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