Depth of sojourn and niche differentiation of benthic blennies (Pisces, Blenniidae) in the Mediterranean sea (Catalonia, NE Spain and Italian coast of the Tyrrhenian sea)

The vertical distribution of nine species of combtooth blennies between the surface and 1,5 m depth was studied at selected rocky shore sections of the Mediterranean Sea in NE Spain and the W coast of Italy. Significant differences in mean depths of sojourn and the degree of depth overlap allow the distinction of species subgroups: species preferring the uppermost shore (Coryphoblennius galerita, Aidablennius sphynx and Lipophrys trigloides), those mostly found in a middle stratum (Lipophrys canevai, Scartella cristata, Parablennius incognitus, Parablennius gattorugine) and two species with the lowest depth of sojourn (Parablennius pilicornis, Parablennius zvonimir). The relative depth position showed little seasonal variation and was similar at both Spanish and ltalian sites. The species of each subgroup which shows a high degree of spatial overlap is distinguished in other dimensions of its ecological niches, in particular by different feeding habits and differences in shelter characteristics. On the basis of exact depth distribution data the present study indicates that depth differences of Mediterranean blennies are very finely tuned and species-specific, even on a broad geographical and seasonal scale. Key words: Vertical zonation, Rocky shore, Ecological niches, Overlap, Microhabitat, Fish assemblageThe vertical distribution of nine species of combtooth blennies between the surface and 1,5 m depth was studied at selected rocky shore sections of the Mediterranean Sea in NE Spain and the W coast of Italy. Significant differences in mean depths of sojourn and the degree of depth overlap allow the distinction of species subgroups: species preferring the uppermost shore (Coryphoblennius galerita, Aidablennius sphynx and Lipophrys trigloides), those mostly found in a middle stratum (Lipophrys canevai, Scartella cristata, Parablennius incognitus, Parablennius gattorugine) and two species with the lowest depth of sojourn (Parablennius pilicornis, Parablennius zvonimir). The relative depth position showed little seasonal variation and was similar at both Spanish and ltalian sites. The species of each subgroup which shows a high degree of spatial overlap is distinguished in other dimensions of its ecological niches, in particular by different feeding habits and differences in shelter characteristics. On the basis of exact depth distribution data the present study indicates that depth differences of Mediterranean blennies are very finely tuned and species-specific, even on a broad geographical and seasonal scale. Key words: Vertical zonation, Rocky shore, Ecological niches, Overlap, Microhabitat, Fish assemblageThe vertical distribution of nine species of combtooth blennies between the surface and 1,5 m depth was studied at selected rocky shore sections of the Mediterranean Sea in NE Spain and the W coast of Italy. Significant differences in mean depths of sojourn and the degree of depth overlap allow the distinction of species subgroups: species preferring the uppermost shore (Coryphoblennius galerita, Aidablennius sphynx and Lipophrys trigloides), those mostly found in a middle stratum (Lipophrys canevai, Scartella cristata, Parablennius incognitus, Parablennius gattorugine) and two species with the lowest depth of sojourn (Parablennius pilicornis, Parablennius zvonimir). The relative depth position showed little seasonal variation and was similar at both Spanish and ltalian sites. The species of each subgroup which shows a high degree of spatial overlap is distinguished in other dimensions of its ecological niches, in particular by different feeding habits and differences in shelter characteristics. On the basis of exact depth distribution data the present study indicates that depth differences of Mediterranean blennies are very finely tuned and species-specific, even on a broad geographical and seasonal scale. Key words: Vertical zonation, Rocky shore, Ecological niches, Overlap, Microhabitat, Fish assemblag

Neuropsychological constraints to human data production on a global scale

Which are the factors underlying human information production on a global level? In order to gain an insight into this question we study a corpus of 252-633 Million publicly available data files on the Internet corresponding to an overall storage volume of 284-675 Terabytes. Analyzing the file size distribution for several distinct data types we find indications that the neuropsychological capacity of the human brain to process and record information may constitute the dominant limiting factor for the overall growth of globally stored information, with real-world economic constraints having only a negligible influence. This supposition draws support from the observation that the files size distributions follow a power law for data without a time component, like images, and a log-normal distribution for multimedia files, for which time is a defining qualia.Comment: to be published in: European Physical Journal

Topological field theories and their symmetries within the Batalin-Vilkovisky framework

We discuss the algebraic construction of topological models (of both Schwarz- and Witten-type) within the Batalin-Vilkovisky formalism and we elaborate on a simple description of vector supersymmetry within this framework

Subitizing with Variational Autoencoders

Numerosity, the number of objects in a set, is a basic property of a given visual scene. Many animals develop the perceptual ability to subitize: the near-instantaneous identification of the numerosity in small sets of visual items. In computer vision, it has been shown that numerosity emerges as a statistical property in neural networks during unsupervised learning from simple synthetic images. In this work, we focus on more complex natural images using unsupervised hierarchical neural networks. Specifically, we show that variational autoencoders are able to spontaneously perform subitizing after training without supervision on a large amount images from the Salient Object Subitizing dataset. While our method is unable to outperform supervised convolutional networks for subitizing, we observe that the networks learn to encode numerosity as basic visual property. Moreover, we find that the learned representations are likely invariant to object area; an observation in alignment with studies on biological neural networks in cognitive neuroscience

Branes with fluxes wrapped on spheres

Following an eight-dimensional gauged supergravity approach we construct the most general solution describing D6-branes wrapped on a Kahler four-cycle taken to be the product of two spheres of different radii. Our solution interpolates between a Calabi-Yau four-fold and the spaces S^2xS^2xS^2xR^2 or S^2xS^2xR^4, depending on generic choices for the parameters. Then we turn on a background four-form field strength, corresponding to D2-branes, and show explicitly how our solution is deformed. For a particular choice of parameters it represents a flow from a Calabi-Yau four-fold times the three-dimensional Minkowski space-time in the ultraviolet, to the space-time AdS_4xQ^{1,1,1} in the infrared. In general, the solution in the infrared has a singularity which within type-IIA supergravity corresponds to the near horizon geometry of the solution for the D2-D6 system. Finally, we uncover the relation with work done in the eighties on Freund-Rubin type compactifications.Comment: 15 pages, Late

M-Theory solutions with AdS factors

Solutions of D=7 maximal gauged supergravity are constructed with metrics that are a product of a n-dimensional anti-de Sitter (AdS) space, with n=2,3,4,5, and certain Einstein manifolds. The gauge fields have the same form as in the recently constructed solutions describing the near-horizon limits of M5-branes wrapping supersymmetric cycles. The new solutions do not preserve any supersymmetry and can be uplifted to obtain new solutions of D=11 supergravity, which are warped and twisted products of the D=7 metric with a squashed four-sphere. Some aspects of the stability of the solutions are discussed.Comment: 30 pages. References adde

The melanoma-specific graded prognostic assessment does not adequately discriminate prognosis in a modern population with brain metastases from malignant melanoma

The melanoma-specific graded prognostic assessment (msGPA) assigns patients with brain metastases from malignant melanoma to 1 of 4 prognostic groups. It was largely derived using clinical data from patients treated in the era that preceded the development of newer therapies such as BRAF, MEK and immune checkpoint inhibitors. Therefore, its current relevance to patients diagnosed with brain metastases from malignant melanoma is unclear. This study is an external validation of the msGPA in two temporally distinct British populations.Performance of the msGPA was assessed in Cohort I (1997-2008, n=231) and Cohort II (2008-2013, n=162) using Kaplan-Meier methods and Harrell's c-index of concordance. Cox regression was used to explore additional factors that may have prognostic relevance.The msGPA does not perform well as a prognostic score outside of the derivation cohort, with suboptimal statistical calibration and discrimination, particularly in those patients with an intermediate prognosis. Extra-cerebral metastases, leptomeningeal disease, age and potential use of novel targeted agents after brain metastases are diagnosed, should be incorporated into future prognostic models.An improved prognostic score is required to underpin high-quality randomised controlled trials in an area with a wide disparity in clinical care

Lifetime and production rate of NOx in the upper stratosphere and lower mesosphere in the polar spring/summer after the solar proton event in October–November 2003

We present altitude-dependent lifetimes of NOx, determined with MIPAS/ENVISAT (the Michelson Interferometer for Passive Atmospheric Sounding/the European Environment Satellite), for the Southern polar region after the solar proton event in October-November 2003. Between 50° S and 90° S and decreasing in altitude they range from about two days at 64 km to about 20 days at 44 km. The lifetimes are controlled by transport, mixing and photochemistry. We infer estimates of dynamical lifetimes by comparison of the observed decay to photochemical lifetimes calculated with the SLIMCAT 3-D Model. Photochemical loss contributes to the observed NOx depletion by 0.1% at 44 km, increasing with altitude to 45% at 64 km. In addition, we show the correlation of modelled ionization rates and observed NOx densities under consideration of the determined lifetimes of NOx, and calculate altitude-dependent effective production rates of NOx due to ionization. For that we compare ionization rates of the AIMOS data base with the MIPAS measurements from 15 October-31 December 2003. We derive effective NOx-production rates to be applied to the AIMOS ionization rates which range from about 0.2 NOx-molecules per ion pair at 44 km to 0.7 NOx-molecules per ion pair at 62 km. These effective production rates are considerably lower than predicted by box model simulations which could hint at an overestimation of the modelled ionization rates. © Author(s) 2013.F. Friederich, H. Nieder, and M. Sinnhuber gratefully acknowledge funding by the Helmholtz society, grant VH-NG-624.Peer Reviewe

Holonomy from wrapped branes

Compactifications of M-theory on manifolds with reduced holonomy arise as the local eleven-dimensional description of D6-branes wrapped on supersymmetric cycles in manifolds of lower dimension with a different holonomy group. Whenever the isometry group SU(2) is present, eight-dimensional gauged supergravity is a natural arena for such investigations. In this paper we use this approach and review the eleven dimensional description of D6-branes wrapped on coassociative 4-cycles, on deformed 3-cycles inside Calabi-Yau threefolds and on Kahler 4-cycles.Comment: 1+8 pages, Latex. Proceedings of the Leuven workshop, 2002. v2: Corrected typos in equations (4)-(8