The early evolutionary history of neo-sex chromosomes in Neotropical grasshoppers, Boliviacris noroestensis (Orthoptera: Acrididae: Melanoplinae)

Neo-sex chromosomes are an important component of chromosome variation in Orthoptera, particularly South American Melanoplinae species, which have proven to be outstanding experimental model system to study the mechanism of sex chromosome evolution in this group of insects. In terms of their origin, most derived sex chromosome mechanisms involve a Robertsonian fusion (i.e. translocation) between the ancestral X chromosome and an autosome. In the grasshopper, Boliviacris noroestensis Ronderos & Cigliano (1990) (Orthoptera: Acrididae: Melanoplinae), our results point to a small degree of differentiation (conserved homology between the XR arm and the neo-Y) of the neo-XY chromosomes, which may be of recent evolutionary origin. However, a simple centric fusion model does not explain their origin, mainly because of the observed reduction in the fundamental number (FN) of arms. We propose two models which, we hope, clarify the genesis of B. noroestensis neo-sex chromosomes. Records of karyotype variation in related species due to multiple rearrangements support our models. We propose a possible adaptive advantage for neo-sex chromosome carriers, such changes perhaps representing the primary force that increases their frequency within natural populations compared with non-fused translocated forms, and occurring without apparent detriment to the microevolutionary forces that may also act, at least at the beginning of the evolutionary history of individuals bearing such neo-sex chromosomes.Fil: Castillo, Elio Rodrigo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Taffarel, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

Simplified placement and management of cutting setons in the treatment of transsphincteric anal fistula: technical note

Background: We report one safe and standardized technique of seton placement and management. Conclusions: A simplified way to manage cutting setons helps to minimize manipulation and may reduce pain. In most patients our technique can be used with no additional anesthesia and in an outpatient settin

Implicit or Explicit Compassion? Effects of Compassion Cultivation Training and Comparison with Mindfulness-based Stress Reduction

Mindfulness-based interventions generally include compassion implicitly, but it remains to be seen whether implicit compassion training can be effective, or if it needs to be trained explicitly through specific meditations and relational practices. This research study had two specific goals. The first was to expand the literature on the effects of compassion-based interventions (CBIs) by assessing the impact of the Compassion Cultivation Training program (CCT) on anxiety, depression, stress, life satisfaction, happiness, mindfulness, empathy, self-compassion, compassion for others, and identification with all humanity, through a waitlist randomized controlled trial in a community sample (study 1). Secondly, this research addressed the following question: Does a CBI—an explicit compassion training—have a differential impact in terms of empathy, compassion, and identification with all humanity, compared to a mindfulness-based intervention (mindfulness-based stress reduction (MBSR)) in which compassion is taught implicitly? (study 2). Groups were assessed at baseline, post-intervention, and 2-month follow-up, and analyses involved repeated-measures of analysis of variance (ANOVA) for group contrasts. Compared to the wait-list group, CCT participants showed significant improvements in psychological well-being (decreased depression and stress, increases in life satisfaction, happiness, mindfulness, and self-compassion) and compassion skills. Both MBSR and CCT were effective in generally enhancing psychological well-being and increasing mindfulness and compassion, but CCT had a greater impact on developing compassionate skills, especially empathic concern and identification with all humanity. This research highlights the potential for a complementary (rather than competitive) relationship between mindfulness- and compassion-based interventions

Dynamics of multi-photon processes in semiconductor heterostructures

The present work is devoted to the study of the dynamics of multi-photon processes in semiconductor heterostructures. A time-dependent description is important for understanding in detail the transient response of semiconductors excited by ultrashort optical pulses. In the first part of this thesis, we set up a phenomenological model based on rate equations, in order to investigate the possibility of measuring degenerate two-photon gain in a semiconductor microcavity. The amplification predicted by the model is fairly low (~2%) and mainly limited by the intra-band relaxation of the carriers, which leads to rapid saturation. In the second part, we develop a general theory for the dynamics of multi-photon processes in semiconductors. It will give insight into complex effects related to the coherence between the bands, which are not included in usual absorption coefficients or susceptibilities. For this purpose, we derive effective multi-band Bloch equations that include resonant multi-photon processes induced by two linearly polarized electromagnetic pulses of frequency close to the band gap and close to the half of the band gap respectively. The benefit of the proposed approach is two-fold. First, the description of the dynamics is restricted to a reduced number of bands. However, the discarded bands are not neglected, but consistently taken into account in the higher order processes. Second, all quantities appearing in the effective multi-band Bloch equations vary on the same time scale, which makes the numerical integration much more efficient. The time-dependent polarization current, as well as some susceptibilities, are derived on a consistent level of approximation, and are discussed in detail. The propagation of the electromagnetic fields is neglected. Such a model is appropriate for the description of low-dimensional quantum confined systems (e.g. quantum wells or quantum wires) excited by two colinearly propagating pulses. It accounts for various linear and nonlinear optical processes, such as one- and two-photon absorption, second-harmonic generation, difference-frequency mixing, or coherent control of photocurrent. In this thesis, the general theory is applied to the study of three specific physical situations. First, we investigate the charge and spin current in a symmetric AlGaAs/GaAs quantum well, injected by interference between one- and two-photon inter-band transitions. We identify new coherent terms in the expression of the current, which contribute significantly to the terahertz emission. The effects of the Stark shifts and the inter-valence band two-photon transitions are also calculated and discussed. Second, we calculate the anisotropic two-photon absorption spectra of an AlGaAs/GaAs V-shaped quantum wire with realistic band structure. The Coulomb interaction is taken into account within the Hartree-Fock approximation. The various excitonic peaks are identified with respect to the involved subbands and to the symmetry properties. We also show that excitons that are dark for one-photon excitation may become bright for two-photon spectroscopy, when the light is polarized perpendicularly to the growth direction, but not along a symmetry axis of the wire. Finally, the last application focuses on the optical injection of current in the presence of excitonic effects. Concentrating on the same AlGaAs/GaAs V-shaped quantum wire, we show that the Coulomb interaction within the Hartree-Fock approximation induces terahertz oscillations in the injected charge current. The oscillation frequency corresponds to the energy spacing between the two lowest excitonic resonances, slightly below the band gap, excited respectively by the laser pulse with frequency close to the band gap, and the one with frequency close to the half of the band gap

Living objects: towards flexible big data sharing

Data sharing and especially enabling third parties to build new services using large amounts of shared data is clearly a trend for the future and a main driver for innovation. However, sharing data is a challenging and involved process today: The owner of the data wants to maintain full and immediate control on what can be done with it, while users are interested in offering new services which may involve arbitrary and complex processing over large volumes of data. Currently, flexibility in building applications can only be achieved with public or non-sensitive data, which is released without restrictions. In contrast, if the data provider wants to impose conditions on how data is used, access to data is centralized and only predefined functions are provided to the users. We advocate for an alternative that takes the best of both worlds: distributing control on data among the data itself to provide flexibility to consumers. To this end, we exploit the well-known concept of object, an abstraction that couples data and code, and make it act and react according to the circumstances.Facultad de Informátic

The Impact of Lateral Gene Transfer in Chlamydia

Lateral gene transfer (LGT) facilitates many processes in bacterial ecology and pathogenesis, especially regarding pathogen evolution and the spread of antibiotic resistance across species. The obligate intracellular chlamydiae, which cause a range of diseases in humans and animals, were historically thought to be highly deficient in this process. However, research over the past few decades has demonstrated that this was not the case. The first reports of homologous recombination in the Chlamydiaceae family were published in the early 1990s. Later, the advent of whole-genome sequencing uncovered clear evidence for LGT in the evolution of the Chlamydiaceae, although the acquisition of tetracycline resistance in Chlamydia (C.) suis is the only recent instance of interphylum LGT. In contrast, genome and in vitro studies have shown that intraspecies DNA exchange occurs frequently and can even cross species barriers between closely related chlamydiae, such as between C. trachomatis, C. muridarum, and C. suis. Additionally, whole-genome analysis led to the identification of various DNA repair and recombination systems in C. trachomatis, but the exact machinery of DNA uptake and homologous recombination in the chlamydiae has yet to be fully elucidated. Here, we reviewed the current state of knowledge concerning LGT in Chlamydia by focusing on the effect of homologous recombination on the chlamydial genome, the recombination machinery, and its potential as a genetic tool for Chlamydia

Living objects: towards flexible big data sharing

Data sharing and especially enabling third parties to build new services using large amounts of shared data is clearly a trend for the future and a main driver for innovation. However, sharing data is a challenging and involved process today: The owner of the data wants to maintain full and immediate control on what can be done with it, while users are interested in offering new services which may involve arbitrary and complex processing over large volumes of data. Currently, flexibility in building applications can only be achieved with public or non-sensitive data, which is released without restrictions. In contrast, if the data provider wants to impose conditions on how data is used, access to data is centralized and only predefined functions are provided to the users. We advocate for an alternative that takes the best of both worlds: distributing control on data among the data itself to provide flexibility to consumers. To this end, we exploit the well-known concept of object, an abstraction that couples data and code, and make it act and react according to the circumstances.Facultad de Informátic