Mitigating Toxic Stress in At-Risk Youth through an Agriculture-Based After School Program

Adverse childhood experiences and accompanying toxic stress have negative impacts on children Of particular interest then is identifying strategies that could help at-risk youth mitigate the impacts of toxic stress Using a phenomenology based qualitatively dominant research approach this study explores dynamics of toxic stress in at-risk youth and how the On The Rise program an agricultural-based after school program for at-risk youth addresses toxic stres

Microheater actuators as a versatile platform for strain engineering in 2D materials

We present microfabricated thermal actuators to engineer the biaxial strain in two-dimensional (2D) materials. These actuators are based on microheater circuits patterned onto the surface of a polymer with a high thermal expansion coefficient. By running current through the microheater one can vary the temperature of the polymer and induce a controlled biaxial expansion of its surface. This controlled biaxial expansion can be transduced to biaxial strain to 2D materials, placed onto the polymer surface, which in turn induces a shift of the optical spectrum. Our thermal strain actuators can reach a maximum biaxial strain of 0.64 % and they can be modulated at frequencies up to 8 Hz. The compact geometry of these actuators results in a negligible spatial drift of 0.03 um/deg, which facilitates their integration in optical spectroscopy measurements. We illustrate the potential of this strain engineering platform to fabricate a strain-actuated optical modulator with single-layer MoS2.Comment: 5 main text figures + 5 supp. info. figure

The role of traps in the photocurrent generation mechanism in thin In-Se photodetectors

Due to the excellent electrical transport properties and optoelectronic performance, thin indium selenide (InSe) has recently attracted attention in the field of 2D semiconducting materials. However, the mechanism behind the photocurrent generation in thin InSe photodetectors remains elusive. Here, we present a set of experiments aimed at explaining the strong scattering in the photoresponsivity values reported in the literature for thin InSe photodetectors. By performing optoelectronic measurements on thin InSe-based photodetectors operated under different environmental conditions we find that the photoresponsivity, the response time and the photocurrent power dependency are strongly correlated in this material. This observation indicates that the photogating effect plays an imporant role for thin InSe flakes, and it is the dominant mechanism in the ultra-high photoresponsivity of pristine InSe devices. In addition, when exposing the pristine InSe photodetectors to the ambient environment we observe a fast and irreversible change in the photoresponse, with a decrease in the photoresponsivity accompanied by an increase of the operating speed. We attribute this photodetector performance change (upon atmospheric exposure) to the decrease in the density of the traps present in InSe, due to the passivation of selenium vacancies by atmospheric oxygen species. This passivation is accompanied by a downward shift of the InSe Fermi level and by a decrease of the Fermi level pinning, which leads to an increase of the Schottky barrier between Au and InSe. Our study reveals the important role of traps induced by defects in tailoring the properties of devices based on 2D materials and offers a controllable route to design and functionalize thin InSe photodetectors to realize devices with either ultrahigh photoresposivity or fast operation speed.Comment: 27 pages, 12 figures, Main text and Supporting Informatio

A system for the deterministic transfer of 2D materials under inert environmental conditions

The isolation of air-sensitive two-dimensional (2D) materials and the race to achieve a better control of the interfaces in van der Waals heterostructures has pushed the scientific community towards the development of experimental setups that allow to exfoliate and transfer 2D materials under inert atmospheric conditions. These systems are typically based on over pressurized N2 of Ar gloveboxes that require the use of very thick gloves to operate within the chamber or the implementation of several motorized micro-manipulators. Here, we set up a deterministic transfer system for 2D materials within a gloveless anaerobic chamber. Unlike other setups based on over-pressurized gloveboxes, in our system the operator can manipulate the 2D materials within the chamber with bare hands. This experimental setup allows us to exfoliate 2D materials and to deterministically place them at a desired location with accuracy in a controlled O2-free and very low humidity (<2% RH) atmosphere. We illustrate the potential of this system to work with air-sensitive 2D materials by comparing the stability of black phosphorus and perovskite flakes inside and outside the anaerobic chamberThis project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement n° 755655, ERC-StG 2017 project 2D-TOPSENSE). EU Graphene Flagship funding (Grant Graphene Core 2, 785219) is acknowledged. RF acknowledges the support from the Spanish Ministry of Economy, Industry and Competitiveness through a Juan de la Cierva-formación fellowship 2017 FJCI2017-32919. QHZ acknowledges the grant from China Scholarship Council (CSC) under No. 201700290035. MS acknowledges the financial support of a fellowship from ‘la Caixa’ Foundation (ID 100010434). The fellowship code is LCF/BQ/IN17/11620040. MS has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 713673. FP acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through the ‘María de Maeztu’ Program for Units of Excellence in R and D (MDM-2014-0377

Modeling Workplace Evacuation Behaviors Using Intelligent Agents

A major challenge in artificial intelligence has been the development of autonomous agents (AAs) capable of displaying believable behaviors. To achieve such objective, the underlying architectures of these intelligent systems have been designed to incorporate Learning Classifier System that provides an adaptation naturally with the environment. It is expected that through the interaction of this type of components, AAs can implement more intelligent and believable behavior. Although the literature reports several computational models of behaviors, attention, and emotions developed to be included in cognitive agent architectures, these have been implemented as separated processes, disregarding essential interactions between these behaviors whose modeling and computational implementation may increase the believability of actions developed by AAs. In this paper, we propose an evolutive computational model. This model is designed to provide AAs with adequate mechanisms to attend and react to conditions and changes in the environment.isa-CTEE

Convolutional neural nets with hyperparameter optimization and feature importance for power system static security assessment

Static security assessment (SSA) is fundamental in electrical network analysis. However, the growing complexity and variability of grid’s operating conditions can make it tedious, slow, computationally intensive, and limited or impractical for on-line applications when traditional approaches are considered. Since this may hinder the emerging analytical duties of system operators, data-driven alternatives are required for faster and sophisticated decision-making. Although different machine learning algorithms (MLAs) could be applied, Convolutional Neural Networks (CNNs) are one of the most powerful models used in many advanced technological developments due to their remarkable capability to identify meaningful patterns in challenging and complex data sets. According to this, a CNN based approach for fast SSA of power systems with N-1 contingency is presented in this paper. To contribute to the automation of model building and tuning, a settings-free strategy to optimize a set of hyperparameters is adopted. Besides, permutation feature importance is considered to identify only a subset of key features and reduce the initial input space. To illustrate the application of the proposed approach, the simulation model of a practical grid in Mexico is used. The superior performance of the CNN alternative is demonstrated by comparing it with two popular MLAs

Endocardial Approach for Substrate Ablation in Brugada Syndrome

Radiofrequency ablation (RFA) in Brugada syndrome (BrS) has been performed by both endocardial and epicardial. The substrate in BrS is not completely understood. We investigate the functional endocardial substrate and its correlation with clinical, electrophysiological and ECG findings in order to guide an endocardial ablation. Two patients agreed to undergo an endocardial biopsy and the samples were examined with transmission electron microscopy (TEM) to investigate the correlation between functional and ultrastructural alterations. About 13 patients (38.7 ± 12.3 years old) with spontaneous type 1 ECG BrS pattern, inducible VF with programmed ventricular stimulation (PVS) and syncope without prodromes were enrolled. Before endocardial mapping, the patients underwent flecainide testing with the purpose of measuring the greatest ST-segment elevation for to be correlated with the size and location of substrate in the electro-anatomic map. Patients underwent endocardial bipolar and electro-anatomic mapping with the purpose of identify areas of abnormal electrograms (EGMs) as target for RFA and determine the location and size of the substrate. When the greatest ST-segment elevation was in the third intercostal space (ICS), the substrate was located upper in the longitudinal plane of the right ventricular outflow tract (RVOT) and a greatest ST-segment elevation in fourth ICS correspond with a location of substrate in lower region of longitudinal plane of RVOT. A QRS complex widening on its initial and final part, with prolonged transmural and regional depolarization time of RVOT corresponded to the substrate located in the anterior-lateral region of RVOT. A QRS complex widening rightwards and only prolonged transmural depolarization time corresponded with a substrate located in the anterior, anterior-septal or septal region of RVOT. RFA of endocardial substrate suppressed the inducibility and ECG BrS pattern during 34.7 ± 15.5 months. After RFA, flecainide testing confirmed elimination of the ECG BrS pattern. Endocardial biopsy showed a correlation between functional and ultrastructural alterations. Endocardial RFA can eliminate the BrS phenotype and inducibility during programmed ventricular stimulation (PVS)