Learning Twig and Path Queries

International audienceWe investigate the problem of learning XML queries, \emph{path} queries and \emph{twig} queries, from examples given by the user. A learning algorithm takes on the input a set of XML documents with nodes annotated by the user and returns a query that selects the nodes in a manner consistent with the annotation. We study two learning settings that differ with the types of annotations. In the first setting the user may only indicate \emph{required nodes} that the query must return. In the second, more general, setting, the user may also indicate \emph{forbidden nodes} that the query must not return. The query may or may not return any node with no annotation. We formalize what it means for a class of queries to be \emph{learnable}. One requirement is the existence of a learning algorithm that is \emph{sound} i.e., always returns a query consistent with the examples given by the user. Furthermore, the learning algorithm should be \emph{complete} i.e., able to produce every query with sufficiently rich examples. Other requirements involve tractability of the learning algorithm and its robustness to nonessential examples. We identify practical classes of Boolean and unary, path and twig queries that are learnable from positive examples. We also show that adding negative examples to the picture renders learning unfeasible

Containment of Shape Expression Schemas for RDF

We study the problem of containment for shape expression schemas (ShEx) for RDF graphs. We identify a subclass of ShEx that has a natural graphical representation in the form of shape graphs and their semantics is captured with a tractable notion of embedding of an RDF graph in a shape graph. When applied to pairs of shape graphs, an embedding is a sufficient condition for containment, and for a practical subclass of deterministic shape graphs, it is also a necessary one, thus yielding a subclass with tractable containment. While for general shape graphs a minimal counter-example i.e., an instance proving non-containment, might be of exponential size, we show that containment is EXP-hard and in coNEXP. Finally, we show that containment for arbitrary ShEx is coNEXP-hard and in coTwoNEXP^NP

Brak wpływu stopnia zwężenia zastawki aortalnej na standardowe parametry płytek krwi — kluczowa rola innych czynników ryzyka sercowo-naczyniowego

Introduction. Calcification of the aortic valve, the main component of degenerative aortic stenosis (AS), results in turbulent blood flow, higher shear stress and may have an effect on the platelet (PLT) parameters. Platelet function and size, which are easily measured automatically during a complete blood count, are proposed as markers of platelet reactivity and risk factors for cardiovascular diseases. Material and methods. 143 patients with AS (mean age: 70 ± 13 y., males 76/53%) were enrolled into the study and divided according to the AS severity: severe AS (n = 89; males 43/48.3%; age IQR: 70 [63–75] y.) and non-severe AS (n = 54; males 63/61.1%; age IQR: 70 [62–76] y.). The clinical data were collected and analyzed with special attention being paid to the cardiovascular risk factors, concomitant diseases (coronary artery disease [CAD], diabetes mellitus, arterial hypertension, obesity). Laboratory tests and echocardiography were assessed in all subjects. Routine admission complete blood cell count was obtained — PLT count, mean PLT volume (MPV), PLT distribution width (PDW) and percentage of giant PLT (giant PLT%) were analyzed. Results. There were no differences between the PLT count, MPV, PDW and giant PLT% when comparing the group with severe AS to the non-severe AS group. Multivariate analysis showed a significant effect of CAD coincidence (β = –0.2, SE = 0.09, p = 0,03) and active smoking (β = –0.2, SE = 0.09, p = 0.03) on the PLT count; obesity (β = 0.2, SE = 0.09, p = 0.03) and CAD (β = –0.2, SE = 0.09, p = 0.03) on MPV; obesity (β = 0.21, SE = 0.09, p = 0.02), thienopyridines (β = 0.19, SE = 0.09, p = 0.03) and LMWH intake (β = 0.21, SE = 0.09, p = 0.02) on PDW; and similarly, obesity (β = 0.23, SE = 0.09, p = 0.01), thienopyridines (β = 0.18, SE = 0.09, p = 0.046) and LMWH intake (β = 0.23, SE = 0.09, p = 0.01) on giant PLT%. Conclusions. Aortic stenosis severity has no effect on PLT count and morphology that are automatically measured. The coincidence of standard cardiovascular risk factors and the CAD effects on the PLT parameters that are established during a standard complete blood count.Wstęp. Kalcyfikacje zastawki aortalnej, będące głównym komponentem degeneracyjnego zwężenia zastawki aortalnej (AS), skutkują turbulentnym przepływem krwi, co z kolei może wpływać na parametry płytek krwi (PLT). Funkcja i wielkość PLT, łatwo oznaczane podczas rutynowej morfologii krwi obwodowej, mogą być markerami aktywności PLT i potencjalnymi czynnikami ryzyka chorób układu sercowo-naczyniowego. Materiał i metody. Do badania włączono 143 pacjentów z AS (średni wiek: 70 ± 13 l., mężczyźni 76/53%) i podzielono na dwie podgrupy zależnie od ciężkości AS — z ciężką AS (mediana wieku: 70 [63–75] l., n = 89, mężczyźni 43/48,3%) oraz nieciężką AS (mediana wieku: 70 [62–76] l., n = 54, mężczyźni 63/61,1%). U wszystkich chorych wykonano przezklatkowe badanie echokardiograficzne oraz zebrano wywiad lekarski, ze szczególnym uwzględnieniem czynników ryzyka chorób układu sercowo-naczyniowego i schorzeń współistniejących (choroby wieńcowej [CAD], cukrzycy typu 2, nadciśnienia tętniczego, otyłości, palenia tytoniu). W wykonanej rutynowo morfologii krwi obwodowej analizie poddano następujące parametry płytkowe: liczbę płytek (PLT count), średnią objętość płytek (MPV), wskaźnik anizocytozy płytek (PDW), odsetek płytek olbrzymich (giant PLT%). Wyniki. Nie obserwowano istotnej różnicy pod względem PLT count, MPV, PDW ani giant PLT%, porównując grupy pod względem ciężkości AS. W przeprowadzonej analizie wieloczynnikowej wykazano istotny wpływ współwystępowania CAD (β = –0,2; SE = 0,09; p = 0,03) i palenia tytoniu (β = –0,2; SE = 0,09; p = 0,03) na PLT count; otyłości (β = 0,2; SE = 0,09; p = 0,03) i CAD (β = –0,2; SE = 0,09; p = 0,03) na MPV; otyłości (β = 0,21; SE = 0,09; p = 0,02), stosowania pochodnych tienopirydyn (β = 0,19; SE = 0,09; p = 0,03) oraz heparyn drobnocząsteczkowych (β = 0,21; SE = 0,09; p = 0,02) na PDW; i podobnie, otyłości (β = 0,23; SE = 0,09; p = 0,01), stosowania pochodnych tienopirydyn (β = 0,18; SE = 0,09; p = 0,046) oraz heparyn drobnocząsteczkowych (β = 0,23; SE = 0,09; p = 0,01) na giant PLT%. Wnioski. Stopień AS nie wpływa na automatycznie mierzoną liczbę i morfologię PLT. Współwystępowanie czynników ryzyka chorób układu sercowo-naczyniowego oraz CAD wpływa na rutynowo oznaczane w morfologii krwi obwodowej parametry płytkowe

Inference of Shape Graphs for Graph Databases

We investigate the problem of constructing a shape graph that describes the structure of a given graph database. We employ the framework of grammatical inference, where the objective is to find an inference algorithm that is both sound, i.e., always producing a schema that validates the input graph, and complete, i.e., able to produce any schema, within a given class of schemas, provided that a sufficiently informative input graph is presented. We identify a number of fundamental limitations that preclude feasible inference. We present inference algorithms based on natural approaches that allow to infer schemas that we argue to be of practical importance

Querying Best Paths in Graph Databases

Querying graph databases has recently received much attention. We propose a new approach to this problem, which balances competing goals of expressive power, language clarity and computational complexity. A distinctive feature of our approach is the ability to express properties of minimal (e.g. shortest) and maximal (e.g. most valuable) paths satisfying given criteria. To express complex properties in a modular way, we introduce labelling-generating ontologies. The resulting formalism is computationally attractive - queries can be answered in non-deterministic logarithmic space in the size of the database

Comparison of biofilm-producing Enterococcus faecalis, Enterococcus faecium, and unusual Enterococcus strains

The present study focused on determining the prevalence of biofilm-forming ability in Enterococ-cus faecalis, E. faecium, and unusual Enterococcus clinical isolates, and comparison of resistance and the prevalence of selected virulence factors among biofilm-positive strains. The ability to form biofilm was detected in 13.3% of E. faecalis, 90% of E. faecium, and 57.1% of unusual Enterococcus strains (p=0.026). All E. faecalis strains were susceptible to β-lactams, while 37.5% of unusual and all E. faecium isolates were resistant to these antibiotics. Resistance to gentamicin was detected in 75% of E. faecalis, 55.5% of E. faecium, and 25% of other strains; resistance to streptomycin in 25%, 83.3%, and 50%, respectively. Analysis of the virulence revealed that the enterococcal surface protein (esp) gene was found in all E. faecium, 75.0% of E. faecalis, and 37.5% of other strains; collagen adhesin gene (ace) in 100%, 25.0%, and 37.5%; and hyaluronidase gene (hyl) in 83.3%, 0%, and 37.5%, respectively. Analysis of the resistance and virulence patterns showed that E. faecium isolates had the greatest variety of virulence and resistance determinants, while the lowest variety was exhibited by unusual strains. These findings indicate that unusual biofilm-producing Enterococcus strains have lower resistance and virulence potency than E. faecalis and E. faecium. DOI: http://dx.doi.org/10.5281/zenodo.100083

The reproductive system of the male and oviparous female of a model organism— the pea aphid, Acyrthosiphon pisum (Hemiptera, Aphididae)

The structure of the reproductive system of the sexual generation—males and oviparous females—of the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera, Aphididae), a serious pest of cultivated plants of Fabaceae, was investigated. For the first time we describe the morphology, histology and ultrastructure of the reproductive system in both morphs of the sexual generation of aphids within one species, using light and fluorescent microscopy, as well as transmission and scanning electron microscopy. The results revealed that males have testes composed of three follicles fused by the upper ends of the vasa efferentia, the vasa deferentia run independently, the accessory glands are asymmetric and the ejaculatory duct shortened. Oviparous females have ovaries composed of seven ovarioles each. The lateral oviducts join to a short common oviduct connected with the unpaired spermatheca and paired accessory glands. Yolky eggs with an aggregation of symbiotic bacteria at the posterior pole are produced. Histologically, the components of genital tracts are broadly similar: the epithelial cells of the walls of the vasa deferentia and accessory glands of the male and oviparous female have secretory functions which correlate with the age of the studied morphs. We also found symbiotic bacteria within the vasa deferentia epithelial cells in males and within the cells of the lateral oviducts of females. Because the pea aphid is listed among the 14 species that are of the greatest economic importance, our results will be useful for managing aphid populations, protecting plants and ensuring global food security

Modern trends in diagnostics of technical condition of material handling equipment drives

This study presents problems of material handling equipment drives as objects of vibration diagnostics, as well as the concept of sensors integrated with a surface exposed to damage on an example of a DiaForce sensor integrated with the surface of the inner race of a rolling bearing according to the solution proposed by Fraunhofer Institute in Braunschweig