Localized low-frequency Neumann modes in 2d-systems with rough boundaries

We compute the relative localization volumes of the vibrational eigenmodes in two-dimensional systems with a regular body but irregular boundaries under Dirichlet and under Neumann boundary conditions. We find that localized states are rare under Dirichlet boundary conditions but very common in the Neumann case. In order to explain this difference, we utilize the fact that under Neumann conditions the integral of the amplitudes, carried out over the whole system area is zero. We discuss, how this condition leads to many localized states in the low-frequency regime and show by numerical simulations, how the number of the localized states and their localization volumes vary with the boundary roughness.Comment: 7 pages, 4 figure

Optimizing methods for linking cinematic features to fMRI data

One of the challenges of naturalistic neurosciences using movie-viewing experiments is how to interpret observed brain activations in relation to the multiplicity of time-locked stimulus features. As previous studies have shown less inter-subject synchronization across viewers of random video footage than story-driven films, new methods need to be developed for analysis of less story-driven contents. To optimize the linkage between our fMRI data collected during viewing of a deliberately non-narrative silent film 'At Land' by Maya Deren (1944) and its annotated content, we combined the method of elastic-net regularization with the model-driven linear regression and the well-established data-driven independent component analysis (ICA) and inter-subject correlation (ISC) methods. In the linear regression analysis, both IC and region-of-interest (ROI) time-series were fitted with time-series of a total of 36 binary-valued and one real-valued tactile annotation of film features. The elastic-net regularization and cross-validation were applied in the ordinary least-squares linear regression in order to avoid over-fitting due to the multicollinearity of regressors, the results were compared against both the partial least-squares (PLS) regression and the un-regularized full-model regression. Nonparametric permutation testing scheme was applied to evaluate the statistical significance of regression. We found statistically significant correlation between the annotation model and 9 ICs out of 40 ICs. Regression analysis was also repeated for a large set of cubic ROIs covering the grey matter. Both IC- and ROI-based regression analyses revealed activations in parietal and occipital regions, with additional smaller clusters in the frontal lobe. Furthermore, we found elastic-net based regression more sensitive than PLS and un-regularized regression since it detected a larger number of significant ICs and ROIs. Along with the ISC ranking methods, our regression analysis proved a feasible method for ordering the ICs based on their functional relevance to the annotated cinematic features. The novelty of our method is - in comparison to the hypothesis-driven manual pre-selection and observation of some individual regressors biased by choice - in applying data-driven approach to all content features simultaneously. We found especially the combination of regularized regression and ICA useful when analyzing fMRI data obtained using non-narrative movie stimulus with a large set of complex and correlated features. (C) 2015 The Authors. Published by Elsevier Inc.Peer reviewe

Narrative comprehension beyond language : Common brain networks activated by a movie and its script

Narratives surround us in our everyday life in different forms. In the sensory brain areas, the processing of narratives is dependent on the media of presentation, be that in audiovisual or written form. However, little is known of the brain areas that process complex narrative content mediated by various forms. To isolate these regions, we looked for the functional networks reacting in a similar manner to the same narrative content despite different media of presentation. We collected 3-T fMRI whole brain data from 31 healthy human adults during two separate runs when they were either viewing a movie or reading its screenplay text. The independent component analysis (ICA) was used to separate 40 components. By correlating the components' time-courses between the two different media conditions, we could isolate 5 functional networks that particularly related to the same narrative content. These TOP-5 components with the highest correlation covered fronto-temporal, parietal, and occipital areas with no major involvement of primary visual or auditory cortices. Interestingly, the top-ranked network with highest modality-invariance also correlated negatively with the dialogue predictor, thus pinpointing that narrative comprehension entails processes that are not language-reliant. In summary, our novel experiment design provided new insight into narrative comprehension networks across modalities.Peer reviewe

Іменники на позначення дрібних речей як посилювачі заперечення (Nouns vith the signification of the things of small value as a emhasis of negation)

У статті описуються випадки вживання певної групи іменників на позначення невеликого розміру або цінності задля надання емфатичності запереченню, що простежується у всіх романських мовах, починаючи із латини. Було зазначено, що у французькій мові такі іменники поступово набували ознаки прислівника, втрачаючи при цьому своє етимологічне та семантичне значення, тобто вони граматизувалися. У загальних рисах, іменники незначної цінності можуть бути еквівалентами «ніщо», іншими словами перифразами ідеї «ніщо» чи синонімами «абсолютно ніщо». (Nouns vith the signification of the things of small value as a emhasis of negation. The article describes the case of the usage of some noun groups with the evaluative meaning to emphasize the negation, that traces in all Romance languages borrowed from Latin. Negation is one of the few truly universal grammatical categories: every language seems to have some grammaticalized means to deny the truth of an ordinary declarative sentence. For the historical linguists, changes in the way that negation is expressed are therefore an ideal testing ground for theories of change, with every language having the potential to provide important data. In the emergence of the new negative markers, we find grammaticalization of lexical items as new grammatical markers of negation: a noun like French pas ‘step’ comes to be reinterpreted as a marking negation. Thus, in French, for example, such nouns gradually gained the signs of adverb and lost their etymological and semantic significance, that is they were grammatized. These noun minimizers are united in such semantic groups, as «plants», «animals», «money», «human and its environment», but we extend them. The article is also devoted to the description of the general indications of such types of constructions with minimizers for possibility of their identification. In general words the nouns with the evaluative meaning can be the equivalents of «nothing», the periphrasis of «nothing» or synonyms of «absolutely nothing».

Розвиток категорії заперечення у романських мовах

У статті описано цикли еволюції заперечення у європейських мовах, визначено місце та розвиток категорії заперечення у деяких романських мовах, передусім різних заперечних засобів: заперечних часток, займенників, прислівників. (The article describes the cycles of evolution of negation in European languages, indicates the place and the development of the category of negation in some Romance languages, especially of various means of negation: negative particles, pronouns, adverbs. We examine O. Jespersen’s Cycle, which illustrates the development of negation by means of French language, the classification of languages made by M. Haspelmath into three types by strict and non-strict negative concord: in a strict negative-concord language, ordinary full clauses containing an n-word always contain the sentential negator too, irrespective of the relative position of the two items, on the other hand, in a non-strict negative-concord language, the sentential negator must be omitted when the n-word precedes the finite verb. Strict negative concord is found in today’s Slavonic and Baltic languages, as well as in Romanian, Greek, Hungarian, and Maltese. Non-strict negative concord is found today in Spanish, Portuguese, and Italian, while Catalan allows both patterns. While Jespersen’s cycle is the best-known historical pathway for the development of sentential negation, it is not the only cyclic development to be found. Croft infers the existence of a second negative cycle on the basis of the typological distribution of certain negative markers. He notes three synchronic relationships between the expression of negation in existentials and that of ordinary sentential negation. B. Camus Bergareche describes the evolution of negation in Romance languages, especially the medieval and modern types, which we represent in a table, besides, in this article, we tried to compose the formula of Romanian negative types and negative structures in Roman area.

Intussusceptive angiogenesis and its role in vascular morphogenesis, patterning, and remodeling

New blood vessels arise initially as blood islands in the process known as vasculogenesis or as new capillary segments produced through angiogenesis. Angiogenesis itself encompasses two broad processes, namely sprouting (SA) and intussusceptive (IA) angiogenesis. Primordial capillary plexuses expand through both SA and IA, but subsequent growth and remodeling are achieved through IA. The latter process proceeds through transluminal tissue pillar formation and subsequent vascular splitting, and the direction taken by the pillars delineates IA into overt phases, namely: intussusceptive microvascular growth, intussusceptive arborization, and intussusceptive branching remodeling. Intussusceptive microvascular growth circumscribes the process of initiation of pillar formation and their subsequent expansion with the result that the capillary surface area is greatly enhanced. In contrast, intussusceptive arborization entails formation of serried pillars that remodel the disorganized vascular meshwork into the typical tree-like arrangement. Optimization of local vascular branching geometry occurs through intussusceptive branching remodeling so that the vasculature is remodeled to meet the local demand. In addition, IA is important in creation of the local organ-specific angioarchitecture. While hemodynamic forces have proven direct effects on IA, with increase in blood flow resulting in initiation of pillars, the preponderant mechanisms are unclear. Molecular control of IA has so far not been unequivocally elucidated but interplay among several factors is probably involved. Future investigations are strongly encouraged to focus on interactions among angiogenic growth factors, angiopoetins, and related receptor

Афективні експліцитні моделі заперечення в іспанській мові (Affective explicit models of negation in Spanish)

У статті розглядаються афективні експліцитні моделі заперечення у розмовній іспанській мові, умотивовується їхнє широке використання, наголошено на їхніх особливих функціях в іспанській мові. Відзначається важлива роль заперечних схем у градації та підсиленні негативної ознаки, на основі чого робиться висновок про дотичність категорії заперечення, оцінки і модальності. (The article explores affective explicit models of negation in Spanish speech; we motivate their widespread use, emphasize their special functions in Spanish. The important role of negative models in gradation and strengthening of negative evaluation was noted, based on which we made the conclusion about the intersection of category of negation with category of evaluation and modality.

Kosketuksen käsittely ihmisen tunto- ja kuuloaivokuorella

Tactile sensation plays an important role in everyday life. While the somatosensory system has been studied extensively, the majority of information has come from studies using animal models. Recent development of high-resolution anatomical and functional imaging techniques has enabled the non-invasive study of human somatosensory cortex and thalamus. This thesis provides new insights into the functional organization of the human brain areas involved in tactile processing using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). The thesis also demonstrates certain optimizations of MEG and fMRI methods. Tactile digit stimulation elicited stimulus-specific responses in a number of brain areas. Contralateral activation was observed in somatosensory thalamus (Study II), primary somatosensory cortex (SI; I, III, IV), and post-auditory belt area (III). Bilateral activation was observed in secondary somatosensory cortex (SII; II, III, IV). Ipsilateral activation was found in the post-central gyrus (area 2 of SI cortex; IV). In addition, phasic deactivation was observed within ipsilateral SI cortex and bilateral primary motor cortex (IV). Detailed investigation of the tactile responses demonstrated that the arrangement of distal-proximal finger representations in area 3b of SI in humans is similar to that found in monkeys (I). An optimized MEG approach was sufficient to resolve such fine detail in functional organization. The SII region appeared to contain double representations for fingers and toes (II). The detection of activations in the SII region and thalamus improved at the individual and group levels when cardiac-gated fMRI was used (II). Better detection of body part representations at the individual level is an important improvement, because identification of individual representations is crucial for studying brain plasticity in somatosensory areas. The posterior auditory belt area demonstrated responses to both auditory and tactile stimuli (III), implicating this area as a physiological substrate for the auditory-tactile interaction observed in earlier psychophysical studies. Comparison of different smoothing parameters (III) demonstrated that proper evaluation of co-activation should be based on individual subject analysis with minimal or no smoothing. Tactile input consistently influenced area 3b of the human ipsilateral SI cortex (IV). The observed phasic negative fMRI response is proposed to result from interhemispheric inhibition via trans-callosal connections. This thesis contributes to a growing body of human data suggesting that processing of tactile stimuli involves multiple brain areas, with different spatial patterns of cortical activation for different stimuli

Stimulus-Rate Sensitivity Discerns Area 3b of the Human Primary Somatosensory Cortex

Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI) to electrical median nerve stimulation doubles in strength when the stimulus rate (SR) increases from 1 to 5 Hz. Here we investigated whether such sensitivity to SR is homogenous within the functionally different subareas of the SI cortex, and whether SR sensitivity would help discern area 3b among the other SI subareas. We acquired 3-tesla functional magnetic resonance imaging (fMRI) data from nine healthy adults who received pneumotactile stimuli in 25-s blocks to three right-hand fingers, either at 1, 4, or 10 Hz. The main contrast (all stimulations pooled vs. baseline), applied to the whole brain, first limited the search to the whole SI cortex. The conjunction of SR-sensitive contrasts [4 Hz − 1 Hz] > 0 and [10 Hz − 1 Hz] > 0 ([4Hz − 1Hz] + [10Hz − 1Hz] > 0), applied to the SI cluster, then revealed an anterior-ventral subcluster that reacted more strongly to both 10-Hz and 4-Hz stimuli than to the 1-Hz stimuli. No other SR-sensitive clusters were found at the group-level in the whole-brain analysis. The site of the SR-sensitive SI subcluster corresponds to the canonical position of area 3b; such differentiation was also possible at the individual level in 5 out of 9 subjects. Thus the SR sensitivity of the BOLD response appears to discern area 3b among other subareas of the human SI cortex.Peer reviewe

Periodic orbit theory in fractal drum

The level statistics of pseudointegrable fractal drums is studied numerically using periodic orbit theory. We find that the spectral rigidity $\Delta_3(L)$, which is a measure for the correlations between the eigenvalues, decreases to quite small values (as compared to systems with only small boundary roughness), thereby approaching the behavior of chaotic systems. The periodic orbit results are in good agreement with direct calculations of $\Delta_3(L)$ from the eigenvalues.Comment: to appear in Physica