Approximation of Hölder continuous homeomorphisms by piecewise affine homeomorphisms

This paper is concerned with the problem of approximating a homeomorphism by piecewise affine homeomorphisms. The main result is as follows: every homeomorphism from a planar domain with a polygonal boundary to ℝ2 that is globally Hölder continuous of exponent α ∈ (0, 1], and whose inverse is also globally Hölder continuous of exponent α can be approximated in the Hölder norm of exponent β by piecewise affine homeomorphisms, for some β ∈ (0,α) that only depends on α. The proof is constructive. We adapt the proof of simplicial approximation in the supremum norm, and measure the side lengths and angles of the triangulation over which the approximating homeomorphism is piecewise affine. The approximation in the supremum norm, and a control on the minimum angle and on the ratio between the maximum and minimum side lengths of the triangulation suffice to obtain approximation in the Hölder norm

Changes in EMG activity during clenching in chronic pain patients with unilateral temporomandibular disorders

[Abstract] The study assessed the differences in electromyographic (EMG) activity recorded during clenching in women with chronic unilateral temporomandibular disorders (TMDs) as compared to control subjects. Seventy-five full dentate, normo-occlusion, right-handed, similarly aged female subjects were recruited. Twenty five subjects presented with right side TMD, 25 presented with left side TMD and 25 pain-free control subjects participated. Using integrated surface EMG over a 1 s contraction, the anterior temporalis and masseter muscles were evaluated bilaterally while subjects performed maximum voluntary clenching. Lower EMG activation was observed in patients with TMD as compared to control subjects (temporalis: 195.74 ± 18.57 vs. 275.74 ± 22.11, P = 0.011; masseters: 151.09 ± 17.37 vs. 283.29 ± 31.87, P < 0.001). An asymmetry index (SAI) was calculated to determine ratios of right to left sided activation. Patients with right-sided TMD demonstrated preferential use of their left-sided muscles (SAI −5.35 ± 4.02) whereas patients with left-sided TMD demonstrated preferential use of their right-sided muscles (SAI 6.95 ± 2.82), (P = 0.016). This unilateral reduction in temporalis and masseter activity could be considered as a specific protective functional adaptation of the neuromuscular system due to nociceptive input. The asymmetry index (SAI) may be a useful measure in discriminating patients with right vs. left-sided TMD.Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; Grant 9/7/1996/DOG/22/7/199

Does having good articulatory skills lead to more fluent speech in first and second languages?

Speaking fluently requires three main processes to run smoothly: conceptualization, formulation, and articulation. This study investigates to what extent fluency in spontaneous speech in both first (L1) and second (L2) languages can be explained by individual differences in articulatory skills. A group of L2 English learners (n = 51) performed three semispontaneous speaking tasks in their L1 Spanish and in their L2 English. In addition, participants performed articulatory skill tasks that measured the speed at which their articulatory speech plans could be initiated (delayed picture naming) and the rate and accuracy at which their articulatory gestures could be executed (diadochokinetic production). The results showed that fluency in spontaneous L2 speech can be predicted by L1 fluency, replicating earlier studies and showing that L2 fluency measures are, to a large degree, measures of personal speaking style. Articulatory skills were found to contribute modestly to explaining variance in both L1 and L2 fluency.Theoretical and Experimental LinguisticsTeaching and Teacher Learning (ICLON

Evolution of screen use among youth between 2012 and 2020 in Switzerland.

To compare the evolution of screen and Internet use by youths between 2012 and 2020 in Switzerland. Cross-sectional studies of 10th-graders (age 13-14) were performed in Switzerland in 2012 and 2020, and compared in bivariate and multivariate analyses on sociodemographic, schooling, physical activity, emotional well-being, and screen use variables. We found that screen use had shifted to smartphones with 71.7 % of youths primarily using this device in 2020 compared to 23.2 % in 2012. In association with this change, young people's screen time had increased dramatically with an odds ratio (OR) of 11.90 for adolescents spending more than 4 h in front of screens in 2020 compared to 2012. No changes were found in the score on the Internet Addiction Test (IAT) to detect problematic screen use and for adolescents' emotional well-being. Furthermore, youths in 2020 engaged in less physical activity lasting 60 min daily, but the frequency of their extracurricular sport participation remained unchanged. Young people spend more time on screens, especially because of an increase in smartphone use in 2020. However, youths do not seem to show more problematic behaviors regarding screen use, nor has this development affected their emotional well-being. The daily and continuous use of new devices is now an integral part of young people's lives. This process seems to be part of the growth of the digital world. However, Internet and screen addiction scales should be adapted to ensure that adolescents in need of help and counseling are identified

The role of input in second language oral ability development in foreign language classrooms: a longitudinal study

The current project longitudinally investigated the extent to which first-year Japanese university students developed their second language (L2) oral ability in relation to increased input in foreign language classrooms. Their spontaneous speech was elicited at the beginning, middle and end of one academic year, and then judged by linguistically trained coders for pronunciation, fluency, vocabulary and grammar qualities. According to the statistical analyses, the total amount of input (operationalized as number of English classes taken and L2 use outside of classrooms) was significantly related to the participants’ quick and immediate development of fluency and lexicogrammar during the first semester. Their pronunciation development was mixed, either subject to continuous change over two academic semesters (for prosody) or limited within the timeframe of the study (for segmentals). Similar to naturalistic L2 speech learning, the findings support the multifaceted role of input in different areas of oral proficiency development in foreign language classrooms

Humanitarian organizations' information practices : procedures and privacy concerns for serving the undocumented

Many humanitarian organizations in the United States work with the information of undocumented migrants to help them secure services that might otherwise be unattainable to them. Information and communication technologies can help their work, but can also significantly exacerbate the risks that undocumented individuals are facing, and expose them to security breakages, leaks, hacks, inadvertent disclosure, and courts requests. This study aims to provide a preliminary understanding of the information practices and systems that US humanitarian organizations employ to protect the privacy of the undocumented individuals they serve. To do so, we conducted interviews and an analysis of organizations' working documents within humanitarian organizations on the US West Coast, including advocacy groups and organizations with ties to higher education. Our outcomes show gaps between current legal standards, technology best practices, and the day‐to‐day functioning of the organizations. We contend the necessity of support to humanitarian organizations in further developing standards and training for digital privacy

The Inverse Scattering Method, Lie-Backlund Transformations and Solitons for Low-energy Effective Field Equations of 5D String Theory

In the framework of the 5D low-energy effective field theory of the heterotic string with no vector fields excited, we combine two non-linear methods in order to construct a solitonic field configuration. We first apply the inverse scattering method on a trivial vacuum solution and obtain an stationary axisymmetric two-soliton configuration consisting of a massless gravitational field coupled to a non-trivial chargeless dilaton and to an axion field endowed with charge. The implementation of this method was done following a scheme previously proposed by Yurova. We also show that within this scheme, is not possible to get massive gravitational solitons at all. We then apply a non-linear Lie-Backlund matrix transformation of Ehlers type on this massless solution and get a massive rotating axisymmetric gravitational soliton coupled to axion and dilaton fields endowed with charges. We study as well some physical properties of the constructed massless and massive solitons and discuss on the effect of the generalized solution generating technique on the seed solution and its further generalizations.Comment: 17 pages in latex, changed title, improved text, added reference

Iron and Nickel spectral opacity calculations in conditions relevant for pulsating stellar envelopes and experiments

Seismology of stars is strongly developing. To address this question we have formed an international collaboration OPAC to perform specific experimental measurements, compare opacity calculations and improve the opacity calculations in the stellar codes [1]. We consider the following opacity codes: SCO, CASSANDRA, STA, OPAS, LEDCOP, OP, SCO-RCG. Their comparison has shown large differences for Fe and Ni in equivalent conditions of envelopes of type II supernova precursors, temperatures between 15 and 40 eV and densities of a few mg/cm3 [2, 3, 4]. LEDCOP, OPAS, SCO-RCG structure codes and STA give similar results and differ from OP ones for the lower temperatures and for spectral interval values [3]. In this work we discuss the role of Configuration Interaction (CI) and the influence of the number of used configurations. We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full CI. To illustrate the importance of this effect we compare different CI approximations (modes) available in HULLAC-v9 [7]. These results are compared to previous predictions and to experimental data. Differences with OP results are discussed.Comment: 4 pages, 3 figures, conference Inertial Fusion Sciences and Applications, Bordeaux, 12th to 16th September 2011; EPJ web of Conferences 201

Arbuscular mycorrhizal fungi from acidic soils favors production of tomatoes and lycopene concentration

This study was supported by FONDECYT 11170641 and MEC80190060 (P. Aguilera), MEC 80180077 (A. Seguel), from Agencia Nacional de Investigación y Desarrollo (ANID, Chile