Eigenvalue Spectra of Functional Networks in fMRI Data and Artificial Models

Full paper available at Springerlink: http://link.springer.com/chapter/10.1007%2F978-3-642-38658-9_19In this work we provide a spectral comparison of functional networks in fMRI data of brain activity and artificial energy-based neural model. The spectra (set of eigenvalues of the graph adjacency matrix) of both networks turn out to obey similar decay rate and characteristic power-law scaling in their middle parts. This extends the set of statistics, which are already confirmed to be similar for both neural models and medical data, by the graph spectrum

Phylogeography and morphological evolution of Pseudechiniscus (Heterotardigrada: Echiniscidae)

Tardigrades constitute a micrometazoan phylum usually considered as taxonomically challenging and therefore difficult for biogeographic analyses. The genus Pseudechiniscus, the second most speciose member of the family Echiniscidae, is commonly regarded as a particularly difficult taxon for studying due to its rarity and homogenous sculpturing of the dorsal plates. Recently, wide geographic ranges for some representatives of this genus and a new hypothesis on the subgeneric classification have been suggested. In order to test these hypotheses, we sequenced 65 Pseudechiniscus populations extracted from samples collected in 19 countries distributed on 5 continents, representing the Neotropical, Afrotropical, Holarctic, and Oriental realms. The deep subdivision of the genus into the cosmopolitan suillus-facettalis clade and the mostly tropical-Gondwanan novaezeelandiae clade is demonstrated. Meridioniscus subgen. nov. is erected to accommodate the species belonging to the novaezeelandiae lineage characterised by dactyloid cephalic papillae that are typical for the great majority of echiniscids (in contrast to pseudohemispherical papillae in the suillus-facettalis clade, corresponding to the subgenus Pseudechiniscus). Moreover, the evolution of morphological traits (striae between dorsal pillars, projections on the pseudosegmental plate IV’, ventral sculpturing pattern) crucial in the Pseudechiniscus taxonomy is reconstructed. Furthermore, broad distributions are emphasised as characteristic of some taxa. Finally, the Malay Archipelago and Indochina are argued to be the place of origin and extensive radiation of Pseudechiniscus

A Framework for Coxeter Spectral Classification of Finite Posets and Their Mesh Geometries of Roots

Following our paper [Linear Algebra Appl. 433(2010), 699–717], we present a framework and computational tools for the Coxeter spectral classification of finite posets J≡(J,⪯). One of the main motivations for the study is an application of matrix representations of posets in representation theory explained by Drozd [Funct. Anal. Appl. 8(1974), 219–225]. We are mainly interested in a Coxeter spectral classification of posets J such that the symmetric Gram matrix GJ:=(1/2)[CJ+CJtr]∈J(ℚ) is positive semidefinite, where CJ∈J(ℤ) is the incidence matrix of J. Following the idea of Drozd mentioned earlier, we associate to J its Coxeter matrix CoxJ:=-CJ·CJ-tr, its Coxeter spectrum speccJ, a Coxeter polynomial coxJ(t)∈ℤ[t], and a Coxeter number  cJ. In case GJ is positive semi-definite, we also associate to J a reduced Coxeter number   čJ, and the defect homomorphism ∂J:ℤJ→ℤ. In this case, the Coxeter spectrum speccJ is a subset of the unit circle and consists of roots of unity. In case GJ is positive semi-definite of corank one, we relate the Coxeter spectral properties of the posets J with the Coxeter spectral properties of a simply laced Euclidean diagram DJ∈{̃n,̃6,̃7,̃8} associated with J. Our aim of the Coxeter spectral analysis of such posets J is to answer the question when the Coxeter type CtypeJ:=(speccJ,cJ,  čJ) of J determines its incidence matrix CJ (and, hence, the poset J) uniquely, up to a ℤ-congruency. In connection with this question, we also discuss the problem studied by Horn and Sergeichuk [Linear Algebra Appl. 389(2004), 347–353], if for any ℤ-invertible matrix A∈n(ℤ), there is B∈n(ℤ) such that Atr=Btr·A·B and B2=E is the identity matrix

Host-feeding behaviour of Dermacentor reticulatus and Dermacentor marginatus in mono-specific and inter-specific infestations

BACKGROUND: Given the sympatric occurrence in some regions of Europe and the great epidemiological significance of D. reticulatus and D. marginatus species, we investigated the behaviour of these ticks during inter-specific and mono-specific host infestations. FINDINGS: The investigations were conducted on rabbits at 20 ± 3 °C and humidity of 38 ± 1 %. The inter-specific infestations groups consisted of 20 females and ten males of D. marginatus and 20 females and ten males of D. reticulatus on each host, whereas mono-specific infestations involved 40 females and 20 males of each species. The investigations have demonstrated competition between the two tick species resulting in modification of the behaviour on the host and the feeding course in D. marginatus females by the presence of D. reticulatus. In the inter-specific group, D. marginatus females attached for a longer time (mean 2.74 ± 1.12 h) than in the mono-specific group (mean 1.24 ± 0.97 h) (p < 0.0001). The feeding period of these females was shorter (9.45 ± 1.30 days) than in the mono-specific group (13.15 ± 2.53 days) (p < 0.0001), but they exhibited a statistically significantly higher body weight in comparison with the females from the mono-specific infestation (p = 0.0155). In D. reticulatus females, no significant difference was found in the host attachment and feeding rates between the mono-specific and inter-specific groups. CONCLUSIONS: The differences in the behaviour of the females from both species during co-feeding reflect physiological adaptation to environmental conditions, which enables them to ingest blood and reproduce. During co-feeding of D. reticulatus and D. marginatus on the same host, two inter-specific systems with different physiological features are formed, which may influence the transmission of tick-borne pathogens

Comparison of treatment results in children with non-high risk acute lymphoblastic leukaemia treated according to ALL-BFM 90 and ALL-IC BFM 2002 regimens – single centre preliminary experience

BackgroundAcute lymphoblastic leukaemia (ALL) represents about 30% of cancer in children and thus is the most common childhood malignancy. Despite the great progress, further improvement of treatment results remains an important problem.AimA comparison of the results of standard risk and intermediate risk group regimens ALL-BFM 90 and ALL IC-BFM 2002 was the subject of our study.Materials/MethodsA retrospective analysis of 41 (18 males and 23 females) children aged 2–15 years (median: 6 years) diagnosed from 25.01.1994 to 9.04.1997 and treated according to ALL-BFM 90 (group A), and 44 (22 males and 22 females) children aged 0-18 years (median: 7 years) diagnosed from 12.10.2002 to 31.12.2005 and treated according to ALL IC BFM-2002 regimen (group B) was performed. For statistical evaluation Kaplan–Meier methods and the log-rank test were used.ResultsRemission on time (day +33) was achieved in 39/41 (94%) children from group A and in 43/44 (98%) children from group B (p=0.07). The average day of achieving remission was 49 (range: 28–109; median: 46) in group A and 39 (range: 31–71; median: 35) in group B (