Search results for "MBL"
showing 10 items of 1636 documents
A late Permian ichthyofauna from the Zechstein Basin, Lithuania-Latvia Region
2019
AbstractThe late Permian is a transformative time, which ended in one of the most significant extinction events in Earth’s history. Fish assemblages are a major component of marine foods webs. The macroevolution and biogeographic patterns of late Permian fish are currently insufficiently known. In this contribution, the late Permian fish fauna from Kūmas quarry (southern Latvia) is described for the first time. As a result, the studied late Permian Latvian assemblage consisted of isolated chondrichthyan teeth ofHelodussp., ?Acrodussp., ?Omanoselachesp. and euselachian type dermal denticles as well as many osteichthyan scales of the Haplolepidae and Elonichthydae; numerous teeth ofPalaeonisc…
Self-Assembly of Supramolecular Polymers of N-Centered Triarylamine Trisamides in the Light of Circular Dichroism: Reaching Consensus between Electro…
2020
The self-assembly of chiral supramolecular polymers is an intricate process that spans a wide range of length scales. Circular dichroism techniques are ideal to study this process as they provide information on the molecular scale but are at the same time also sensitive probes of the long-range interactions that control the growth and morphology of these polymers. As yet, Electronic Circular Dichroism that uses electronic transitions as a probe has by far been the method of choice while Vibrational Circular Dichroism, which uses vibrational transitions to probe structure, is much less employed. Here, we report experimental and theoretical studies of the self-assembly of helical supramolecul…
Tandem repeats lead to sequence assembly errors and impose multi-level challenges for genome and protein databases
2019
AbstractThe widespread occurrence of repetitive stretches of DNA in genomes of organisms across the tree of life imposes fundamental challenges for sequencing, genome assembly, and automated annotation of genes and proteins. This multi-level problem can lead to errors in genome and protein databases that are often not recognized or acknowledged. As a consequence, end users working with sequences with repetitive regions are faced with ‘ready-to-use’ deposited data whose trustworthiness is difficult to determine, let alone to quantify. Here, we provide a review of the problems associated with tandem repeat sequences that originate from different stages during the sequencing-assembly-annotatio…
Generating a Gray code for prefix normal words in amortized polylogarithmic time per word
2020
A prefix normal word is a binary word with the property that no substring has more $1$s than the prefix of the same length. By proving that the set of prefix normal words is a bubble language, we can exhaustively list all prefix normal words of length $n$ as a combinatorial Gray code, where successive strings differ by at most two swaps or bit flips. This Gray code can be generated in $\Oh(\log^2 n)$ amortized time per word, while the best generation algorithm hitherto has $\Oh(n)$ running time per word. We also present a membership tester for prefix normal words, as well as a novel characterization of bubble languages.
On prefix normal words and prefix normal forms
2016
A $1$-prefix normal word is a binary word with the property that no factor has more $1$s than the prefix of the same length; a $0$-prefix normal word is defined analogously. These words arise in the context of indexed binary jumbled pattern matching, where the aim is to decide whether a word has a factor with a given number of $1$s and $0$s (a given Parikh vector). Each binary word has an associated set of Parikh vectors of the factors of the word. Using prefix normal words, we provide a characterization of the equivalence class of binary words having the same set of Parikh vectors of their factors. We prove that the language of prefix normal words is not context-free and is strictly contai…
Generalized Logical Operations among Conditional Events
2018
We generalize, by a progressive procedure, the notions of conjunction and disjunction of two conditional events to the case of n conditional events. In our coherence-based approach, conjunctions and disjunctions are suitable conditional random quantities. We define the notion of negation, by verifying De Morgan’s Laws. We also show that conjunction and disjunction satisfy the associative and commutative properties, and a monotonicity property. Then, we give some results on coherence of prevision assessments for some families of compounded conditionals; in particular we examine the Frechet-Hoeffding bounds. Moreover, we study the reverse probabilistic inference from the conjunction $\mathcal…
Quasi conjunction, quasi disjunction, t-norms and t-conorms: Probabilistic aspects
2013
We make a probabilistic analysis related to some inference rules which play an important role in nonmonotonic reasoning. In a coherence-based setting, we study the extensions of a probability assessment defined on $n$ conditional events to their quasi conjunction, and by exploiting duality, to their quasi disjunction. The lower and upper bounds coincide with some well known t-norms and t-conorms: minimum, product, Lukasiewicz, and Hamacher t-norms and their dual t-conorms. On this basis we obtain Quasi And and Quasi Or rules. These are rules for which any finite family of conditional events p-entails the associated quasi conjunction and quasi disjunction. We examine some cases of logical de…
An ensemble approach to short-term forecast of COVID-19 intensive care occupancy in Italian Regions
2020
Abstract The availability of intensive care beds during the COVID‐19 epidemic is crucial to guarantee the best possible treatment to severely affected patients. In this work we show a simple strategy for short‐term prediction of COVID‐19 intensive care unit (ICU) beds, that has proved very effective during the Italian outbreak in February to May 2020. Our approach is based on an optimal ensemble of two simple methods: a generalized linear mixed regression model, which pools information over different areas, and an area‐specific nonstationary integer autoregressive methodology. Optimal weights are estimated using a leave‐last‐out rationale. The approach has been set up and validated during t…
Binary jumbled string matching for highly run-length compressible texts
2012
The Binary Jumbled String Matching problem is defined as: Given a string $s$ over $\{a,b\}$ of length $n$ and a query $(x,y)$, with $x,y$ non-negative integers, decide whether $s$ has a substring $t$ with exactly $x$ $a$'s and $y$ $b$'s. Previous solutions created an index of size O(n) in a pre-processing step, which was then used to answer queries in constant time. The fastest algorithms for construction of this index have running time $O(n^2/\log n)$ [Burcsi et al., FUN 2010; Moosa and Rahman, IPL 2010], or $O(n^2/\log^2 n)$ in the word-RAM model [Moosa and Rahman, JDA 2012]. We propose an index constructed directly from the run-length encoding of $s$. The construction time of our index i…
A water-soluble hexa-peri-hexabenzocoronene: synthesis, self-assembly and role as template for porous silica with aligned nanochannels
2005
A water-soluble hexa-peri-hexabenzocoronene was prepared and shown to undergo ordered columnar self-assembly either in water solution or bulk and therefore served as template for the fabrication of porous silica with aligned nanochannels.