Non-Abelian supertubes

SCOAP

TOMOBFLOW: feature-preserving noise filtering for electron tomography

<p>Abstract</p> <p>Background</p> <p>Noise filtering techniques are needed in electron tomography to allow proper interpretation of datasets. The standard linear filtering techniques are characterized by a tradeoff between the amount of reduced noise and the blurring of the features of interest. On the other hand, sophisticated anisotropic nonlinear filtering techniques allow noise reduction with good preservation of structures. However, these techniques are computationally intensive and are difficult to be tuned to the problem at hand.</p> <p>Results</p> <p>TOMOBFLOW is a program for noise filtering with capabilities of preservation of biologically relevant information. It is an efficient implementation of the Beltrami flow, a nonlinear filtering method that locally tunes the strength of the smoothing according to an edge indicator based on geometry properties. The fact that this method does not have free parameters hard to be tuned makes TOMOBFLOW a user-friendly filtering program equipped with the power of diffusion-based filtering methods. Furthermore, TOMOBFLOW is provided with abilities to deal with different types and formats of images in order to make it useful for electron tomography in particular and bioimaging in general.</p> <p>Conclusion</p> <p>TOMOBFLOW allows efficient noise filtering of bioimaging datasets with preservation of the features of interest, thereby yielding data better suited for post-processing, visualization and interpretation. It is available at the web site <url>http://www.ual.es/%7ejjfdez/SW/tomobflow.html</url>.</p

The Epstein-Barr Virus Episome Maneuvers between Nuclear Chromatin Compartments during Reactivation.

The human genome is structurally organized in three-dimensional space to facilitate functional partitioning of transcription. We learned that the latent episome of the human Epstein-Barr virus (EBV) preferentially associates with gene-poor chromosomes and avoids gene-rich chromosomes. Kaposi's sarcoma-associated herpesvirus behaves similarly, but human papillomavirus does not. Contacts on the EBV side localize to OriP, the latent origin of replication. This genetic element and the EBNA1 protein that binds there are sufficient to reconstitute chromosome association preferences of the entire episome. Contacts on the human side localize to gene-poor and AT-rich regions of chromatin distant from transcription start sites. Upon reactivation from latency, however, the episome moves away from repressive heterochromatin and toward active euchromatin. Our work adds three-dimensional relocalization to the molecular events that occur during reactivation. Involvement of myriad interchromosomal associations also suggests a role for this type of long-range association in gene regulation.IMPORTANCE The human genome is structurally organized in three-dimensional space, and this structure functionally affects transcriptional activity. We set out to investigate whether a double-stranded DNA virus, Epstein-Barr virus (EBV), uses mechanisms similar to those of the human genome to regulate transcription. We found that the EBV genome associates with repressive compartments of the nucleus during latency and with active compartments during reactivation. This study advances our knowledge of the EBV life cycle, adding three-dimensional relocalization as a novel component to the molecular events that occur during reactivation. Furthermore, the data add to our understanding of nuclear compartments, showing that disperse interchromosomal interactions may be important for regulating transcription

Black hole mergers induced by tidal encounters with a galactic centre black hole

We discuss the properties of stellar mass black hole (BH) mergers induced by tidal encounters with a massive BH at galactic centres or potentially in dense star clusters. The tidal disruption of stellar binaries by a massive BH is known to produce hypervelocity stars. However, such a tidal encounter does not always lead to the break-up of binaries. Since surviving binaries tend to become hard and eccentric, this process can produce BH mergers in principle. For initially circular binaries, we show that the gravitational wave (GW) merger times become shorter by a factor of more than 102 (105) in 10 per cent (1 per cent) of the surviving cases. This reduction is primarily due to the growth in binary’s eccentricity at the tidal encounter.We also investigate the effective spins of the survivors, assuming that BH spins are initially aligned with the binary orbital angular momentum. We find that binary orientations can flip in the opposite direction at the tidal encounter. For the survivors with large merger time reduction factors, the effective spin distribution is rather flat. We estimate the merger rate due to the tidal encounter channel to be ∼0.6Gpc−3 yr−1. This mechanism is unlikely to be the dominant formation channel of BH mergers. However, the current and near-future GW observatories are expected to detect an enormous number of BH mergers. If mergers are found in the vicinity of massive BHs (e.g. the detection of GW lensing echoes or preceding extreme-mass-ratio bursts), this mechanism would provide a possible explanation for their origin

Validation in clinical population of the Problematic Internet Entertainment Use Scale for Adults (PIEUSAd)

Addiction to technologies has been a widely debated scientific and clinically, being a condition for further study as potential psychiatric disorder. Some Spanish scales measure Internet addiction, but no one has been validated clinically. The aims were to describe a clinical sample of patients in treatment for a technology addiction, and to validate clinically the “Problematic Internet Entertainment Use Scale for Adults” (PIEUSAd). Little-scale clinical adult sample (N=31; 71 % men, and an age mean of 33.31) was selected, collecting socio-demographic and clinical data, technological usages, and the PIEUSAd and Compulsive Internet Use Scale in a survey. The setting was a public health center in Barcelona (Spain). The patients in treatment for a technological addiction as primary diagnosis were usually young males, which suffer from a genuine e-addiction (above all, internet addiction, gaming and cybersex); only the middle seems to have a dual pathology (usually another addiction). They are usually referred by other clinician and the majority don’t have previous psychiatric care. The PIEUSAd showed large variability in item scored, and high factor and construct validity, and excellent reliability (a=0.98). In conclusion, the heterogeneity in the characteristics of patients is evidenced. Moreover, the PIEUSAd has been clinical validated to do a better screen in technological addictions, where “loss of control” and “evasion” seems to be the prevalent addictive symptoms in these types of patients. Spanish abstract: La adicción a las tecnologías ha sido debatida ampliamente tanto científica como clínicamente, siendo una condición a estudiar como potencial trastorno psiquiátrico. Algunas escalas españolas miden la adicción al internet, pero ninguna ha sido validada clínicamente. Los objetivos son describir la muestra clínica de pacientes en tratamiento por una adicción tecnológica, así como validar clínicamente la “Problematic Internet Entertainment Use Scale for Adults” (PIEUSAd). Una muestra clínica a pequeña escala (N=31; 71 % hombres, con una edad media de 33,31) fue seleccionada, se recogieron datos socio-demográficos, clínicos y de uso de tecnologías, así como la PIEUSAd y la “Compulsive Internet Use Scale” a través de una encuesta. El contexto fue un centro de salud pública de Barcelona (España). Los pacientes en tratamiento por una adicción tecnológica como primer diagnóstico eran usualmente hombres jóvenes que sufrían de una e-adicción genuina (sobre todo, adicción a internet, videojuegos o cibersexo); solo la mitad parecía sufrir una patología dual (normalmente otra adicción). Eran normalmente derivados por otros profesionales de la salud y la mayor parte no habían sido tratados psiquiá- tricamente con anterioridad. La PIEUSAd mostró gran variabilidad en sus puntuaciones, alta validez factorial y de constructo, y excelente fiabilidad (a=0,98). En conclusión, la heterogeneidad de las características de los pacientes fue evidenciada. Además, la PIEUSAd ha sido validada clínicamente para poder hacer un mejor cribado en las adicciones tecnológicas, donde la “pérdida de control” y la “evasión” parecen ser los síntomas prevalentes en estos tipos de pacientes

Diferencias psicopatológicas en mujeres con Dependencia Emocional con y sin uso de sustancias ilegales comórbido

En este artículo se presenta un análisis clínico de las diferencias psicopatológicas entre dos grupos de pacientes, mujeres, con problemas de Dependencia Emocional con y sin consumo de sustancias ilegales comórbido. Las pacientes fueron evaluadas mediante los cuestionarios TDS100, SCL-90-R, BIS-11 y una entrevista semiestructurada adaptada de la entrevista SCID-I. Los grupos se formaron en función de si existía consumo de drogas o no en el momento de la evaluación. A través de los resultados hallados, se puede concluir que el grupo de mujeres con un consumo ocasional de drogas presenta una mayor gravedad en la escala de Acomodación medida a través del TDS-100, así como puntuaciones más altas en psicopatología comórbida (Sensibilidad Interpersonal, Ansiedad, Hostilidad, Ideación paranoide, Psicoticismo y GSI) medida por el SCL-90-R. Finalmente, el grupo con uso de drogas obtuvo puntuaciones significativamente más altas en la subescala Impulsividad Motora medida por el BIS-11. English abstract: In this article we present a clinical analysis of the psychopathological differences between women patients with Affective Dependence problems with and without comorbid substance use. The patients were assessed trough the TDS-100, SCL-90-R, BIS-11 questionnaires and a semi-structured interview adapted from the SCID-I interview. The groups were created based on the substance use at the moment of the assessment. The results reveal that the group of women with occasional use of drugs shows higher severity in the Accommodation scale measured trough the TDS-100 and in the comorbid psychopathology measured by the SCL-90R (Interpersonal Sensitivity, Anxiety, Hostility, Paranoid ideation, Psychoticism y GSI). Finally, the group with drug use obtained significantly higher scores in the Motor Impulsiveness subscale measured by the BIS-11

Transfer Functions for Protein Signal Transduction: Application to a Model of Striatal Neural Plasticity

We present a novel formulation for biochemical reaction networks in the context of signal transduction. The model consists of input-output transfer functions, which are derived from differential equations, using stable equilibria. We select a set of 'source' species, which receive input signals. Signals are transmitted to all other species in the system (the 'target' species) with a specific delay and transmission strength. The delay is computed as the maximal reaction time until a stable equilibrium for the target species is reached, in the context of all other reactions in the system. The transmission strength is the concentration change of the target species. The computed input-output transfer functions can be stored in a matrix, fitted with parameters, and recalled to build discrete dynamical models. By separating reaction time and concentration we can greatly simplify the model, circumventing typical problems of complex dynamical systems. The transfer function transformation can be applied to mass-action kinetic models of signal transduction. The paper shows that this approach yields significant insight, while remaining an executable dynamical model for signal transduction. In particular we can deconstruct the complex system into local transfer functions between individual species. As an example, we examine modularity and signal integration using a published model of striatal neural plasticity. The modules that emerge correspond to a known biological distinction between calcium-dependent and cAMP-dependent pathways. We also found that overall interconnectedness depends on the magnitude of input, with high connectivity at low input and less connectivity at moderate to high input. This general result, which directly follows from the properties of individual transfer functions, contradicts notions of ubiquitous complexity by showing input-dependent signal transmission inactivation.Comment: 13 pages, 5 tables, 15 figure

Fossils reveal the complex evolutionary history of the mammalian regionalized spine.

A unique characteristic of mammals is a vertebral column with anatomically distinct regions, but when and how this trait evolved remains unknown. We reconstructed vertebral regions and their morphological disparity in the extinct forerunners of mammals, the nonmammalian synapsids, to elucidate the evolution of mammalian axial differentiation. Mapping patterns of regionalization and disparity (heterogeneity) across amniotes reveals that both traits increased during synapsid evolution. However, the onset of regionalization predates increased heterogeneity. On the basis of inferred homology patterns, we propose a "pectoral-first" hypothesis for region acquisition, whereby evolutionary shifts in forelimb function in nonmammalian therapsids drove increasing vertebral modularity prior to differentiation of the vertebral column for specialized functions in mammals