The stellar host in star-forming low-mass galaxies: Evidence for two classes

The morphological evolution of star-forming galaxies provides important clues to understand their physical properties, as well as the triggering and quenching mechanisms of star formation. We aim at connecting morphology and star-formation properties of low-mass galaxies (median stellar mass $\sim$ 10$^{8.5}$ M$_{\odot}$) at low redshift ($z<0.36$). We use a sample of medium-band selected star-forming galaxies from the GOODS-North field. H$\alpha$ images for the sample are created combining both spectral energy distribution fits and HST data. Using them, we mask the star forming regions to obtain an unbiased two-dimensional model of the light distribution of the host galaxies. For this purpose we use $\texttt{PHI}$, a new Bayesian photometric decomposition code. We apply it independently to 7 HST bands assuming a S\'ersic surface brightness model. Star-forming galaxy hosts show low S\'ersic index (with median $n$ $\sim$ 0.9), as well as small sizes (median $R_e$ $\sim$ 1.6 kpc), and negligible change of the parameters with wavelength (except for the axis ratio, which grows with wavelength). Using a clustering algorithm, we find two different classes of star-forming galaxies: A more compact, redder, and high-$n$ (class A) and a more extended, bluer and lower-$n$ one (class B). We also find evidence that the first class is more spheroidal-like. In addition, we find that 48% of the analyzed galaxies present negative color gradients (only 5% are positive). The host component of low-mass star-forming galaxies at $z<0.36$ separates into two different classes, similar to what has been found for their higher mass counterparts. The results are consistent with an evolution from class B to class A. Several mechanisms from the literature, like minor and major mergers, and violent disk instability, can explain the physical process behind the likely transition between the classes. [abridged]Comment: Accepted for publication in Astronomy & Astrophysics. 13 pages, 11 figure

The MHD Alfven wave oscillation model of kHz Quasi Periodic Oscillations of Accreting X-ray Binaries

We ascribe the interpretation of the twin kilohertz Quasi Periodic Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to MHD Alfven wave oscillations in the different mass density regions of the accreted matter at the preferred radius, and the upper kHz QPO frequency coincides with the Keplerian frequency. The proposed model concludes that the kHz QPO frequencies depend inversely on the preferred radius, and that theoretical relation between the upper frequency (\nt) and the lower frequency (\no) is \no \sim \nt^{2}, which is similar to the measured empirical relation. The separation between the twin frequencies decreases (increases) with increasing kHz QPO frequency if the lower kHz QPO frequency is more (less) than $\sim$ 400 Hz.Comment: Accepted by Astron. & Astrophys., 4 pages, 4 figure

The origin of large amplitude oscillations of dust particles in a plasma sheath

Micron-size charged particles can be easily levitated in low-density plasma environments. At low pressures, suspended particles have been observed to spontaneously oscillate around an equilibrium position. In systems of many particles, these oscillations can catalyze a variety of nonequilibrium, collective behaviors. Here, we report spontaneous oscillations of single particles that remain stable for minutes with striking regularity in amplitude and frequency. The oscillation amplitude can also exceed 1 cm, nearly an order of magnitude larger than previously observed. Using an integrated experimental and numerical approach, we show how the motion of an individual particle can be used to extract the electrostatic force and equilibrium charge variation in the plasma sheath. Additionally, using a delayed-charging model, we are able to accurately capture the nonlinear dynamics of the particle motion, and estimate the particle's equilibrium charging time in the plasma environment

Adult social isolation leads to anxiety and spatial memory impairment: Brain activity pattern of COx and c-Fos

Social isolation during adulthood is a frequent problem that leads to a large variety of adverse emotional and cognitive effects. However, most of the social isolation rodent procedures begin the separation early post-weaning. This work explores locomotor activity, anxiety-like behaviour, and spatial working memory after twelve weeks of adult social isolation. In order to study the functional contribution of selected brain areas following a working memory task, we assessed neuronal metabolic activity through quantitative cytochrome oxidase histochemistry and c-Fos immunohistochemistry. Behaviourally, we found that isolated animals (IS) showed anxiety-like behaviour and worse working memory than controls, whereas motor functions were preserved. Moreover, IS rats showed lower levels of learning-related c-Fos immunoreactivity, compared to controls, in the medial prefrontal cortex (mPFC), ventral tegmental area (VTA), and nucleus accumbens shell. In addition, the IS group showed lower neuronal metabolic activity in the mPFC, VTA, and CA1 subfield of the hippocampus. These results indicate that twelve weeks of social isolation in adult rats leads to different behavioural and brain alterations, and they highlight the importance of social support, not only in development, but also in adulthood

Functional MRI of Language Processing and Recovery

__Abstract__ My thesis describe the utility of implementing fMRI to investigate how the language system is reorganized in brain damaged patients. Specifically for aphasia research fMRI allows to show how specific language treatment methods have the potential to enhance language reorganization and therefore optimize language recovery. Chapter 2 provides a brief introduction into the basics of language fMRI and task design for current applications of this technique in both clinical and research practice. I also summarized how different language levels have been explored with a variety of language tasks that have improved the neuroanatomical models of language processing. Chapter 3 explores the cerebro-cerebellar language lateralization pattern in healthy participants and in brain tumors patients with a focus on atypical language representation. Chapter 4 studies the differential auditory processing of spoken and melodically intoned language underlying MIT therapy. Chapter 5 focuses on the neural substrate of phonological and semantic auditory, i.e. receptive, processing in healthy older adults, group who is more applicable to aphasia research. I specifically focused on the functional specialization within the left inferior frontal gyrus (IFG), given its proposed important role for the recovery of language functions in aphasia. Chapter 6 explores the relationship between language lateralization and language recovery, both at the level of language production and comprehension, in 36 patients with mild and severe chronic aphasia after left hemispheric stroke. Chapter 7 investigates whether intensive MIT induces a shift in language lateralization in sub-acute and chronic non-fluent aphasic patients

Analysis of accompaniment situations for the improvement of inclusive teaching

Improving teacher training processes is one of the essential challenges for the improvement of inclusive practice. Despite numerous efforts, the results show the need to seek new training strategies such as accompaniment in the classroom. This study analyzes the assistance offered in a training program based on the accompaniment of in-service teachers through situations of modeling practice inclusive in the classroom. Those who act as trainers are fellow teachers from the same school who are more trained in inclusive practice. A qualitative methodology is used through the study of three cases of collaboration between support teachers and teachers throughout an academic year. The joint management between participants on participation, task, and meanings was analyzed in planning sessions, development, and assessment of the practice in the classroom held during an academic year. The results presented empirical evidence of sustained assistance in the construction of collaboration and shared meanings during complete accompaniment processes in the classroom. The results show differences in attendance, in all the three cases, as well as changes in the teacher's behavior