Intercalation events visualized in single microcrystals of graphite.

The electrochemical intercalation of layered materials, particularly graphite, is fundamental to the operation of rechargeable energy-storage devices such as the lithium-ion battery and the carbon-enhanced lead-acid battery. Intercalation is thought to proceed in discrete stages, where each stage represents a specific structure and stoichiometry of the intercalant relative to the host. However, the three-dimensional structures of the stages between unintercalated and fully intercalated are not known, and the dynamics of the transitions between stages are not understood. Using optical and scanning transmission electron microscopy, we video the intercalation of single microcrystals of graphite in concentrated sulfuric acid. Here we find that intercalation charge transfer proceeds through highly variable current pulses that, although directly associated with structural changes, do not match the expectations of the classical theories. Evidently random nanoscopic defects dominate the dynamics of intercalation

Electron beam-induced current imaging with two-angstrom resolution.

An electron microscope's primary beam simultaneously ejects secondary electrons (SEs) from the sample and generates electron beam-induced currents (EBICs) in the sample. Both signals can be captured and digitized to produce images. The off-sample Everhart-Thornley detectors that are common in scanning electron microscopes (SEMs) can detect SEs with low noise and high bandwidth. However, the transimpedance amplifiers appropriate for detecting EBICs do not have such good performance, which makes accessing the benefits of EBIC imaging at high-resolution relatively more challenging. Here we report lattice-resolution imaging via detection of the EBIC produced by SE emission (SEEBIC). We use an aberration-corrected scanning transmission electron microscope (STEM), and image both microfabricated devices and standard calibration grids

Irreversibility at macromolecular scales in the flake graphite of the lithium-ion battery anode.

Charging a commercial lithium-ion battery intercalates lithium into the graphite-based anode, creating various lithium carbide structures. Despite their economic importance, these structures and the dynamics of their charging-discharging transitions are not well-understood. We have videoed single microcrystals of high-quality, natural graphite undergoing multiple lithiation-delithiation cycles. Because the equilibrium lithium-carbide compounds corresponding to full, half, and one-third charge are gold, red, and blue respectively, video observations give direct insight into both the macromolecular structures and the kinematics of charging and discharging. We find that the transport during the first lithiation is slow and orderly, and follows the core-shell or shrinking annuli model with phase boundaries moving at constant velocities (i.e. non-diffusively). Subsequent lithiations are markedly different, showing transport that is both faster and disorderly, which indicates that the initially pristine graphite is irreversibly and considerably altered during the first cycle. In all cases deintercalation is not the time-reverse of intercalation. These findings both illustrate how lithium enters nearly defect-free host material, and highlight the differences between the idealized case and an actual, cycling graphite anode

Incorporating Socio-Scientific Issues into the 5E Model for Learning: Engaging Students in Science through Emotional Connection, Kinesthetic Movement and Real World Phenomenon.

This article presents an argument for the use of socio-scientific issues in the science classroom as a was to make real world connections and engage students in content. This article can work like an active work book for teachers to use as a reference for lesson plans for each of the NYS science standards. Following are 24 activities, one for each of the 24 Next Generation Science Standards as well as supporting research and theories. Each activity introduces students to a socio-scientific issue and acts as an engaging activity to fit with in the 5E model for science learning. Any of these activities can be done at multiple points of the 5E model and can be incorporated into lessons surrounding the standard in many unique ways, but all are intended to be ENGAGING. All activities include a fully engaging, multimodal activity that must be followed up by a class discussion of the issue. These activities are intended to grasp the interest of the students and act as a gateway into the depth and content of the topic. These activities cover the Life Science standards, which include four broad topics broken into 24 standards. There is one SSI for each standard at the high school level totaling 24 activities. These activities are intended for use with 9th and 10th grade living environment students. All socio-scientific issues are applicable at the middle school level or at the 11th/ 12th/ AP levels, content and depth may need to be revised. If the activities presented are not suited for your classroom, you may use this as a reference book for socio-scientific issues related to the Next Generation Science Standards for Life Science. Given the changing nature of education merged with the growth of technology, each activity page is equipped with an online adaptation for remote learning.SUNY BrockportEducation and Human DevelopmentMaster of Science in Education (MSEd)Education and Human Development Master's These

A SQL front-end semantic data model

SQLSDM is a front end semantic data model to a SQL relational database management system (RDBMS). SQLSDM provides a more semantically complete RDBMS through the implementation of a Domain and Relational Integrity scheme. SQLSDM provides integrity definition functions and a sub-system to interpret SQL commands . Integrity system tables are created through the use of SQLSDM \u27 s domain definition command and SQL \u27 s CREATE TABLE command. As SQL database update commands are interpreted, SQLSDM uses these integrity tables to enforce domain and referential integrity. SQLSDM operates virtually transparent to the user and provides for greater database consistency and semantic control. Furthermore, SQLSDM is designed and engineered to be a portable front-end that may be implemented on any SQL relational database management system

Optometrists show rudimentary understanding of evidence-based practice but are ready to embrace it: can barriers be overcome?

Evidence-based practice (EBP) involves integration of the best available evidence from research, the patient's preferences or circumstances, the clinical environment and the health practitioner's expertise. There have been several qualitative studies of EBP in health-care but none has focused on the profession of optometry. Therefore, the aim of the present study was to assess optometrists' perceptions of EBP in optometry

Trait anxiety: a hidden variable in physiological and pathological processes

Nell\u2019uomo esiste una differenza nella risposta agli stimoli stressogeni, che dipende dalla personale predisposizione all\u2019ansia, detta specificatamente \u201ctratto d\u2019ansia\u201d. La differente suscettibilit\ue0 all\u2019ansia \ue8 stata studiata nei roditori creando ceppi selezionati per tratti di elevata e bassa ansia; inoltre \ue8 stato dimostrato, sia nell\u2019uomo che nei ceppi selezionati di roditori, che differenti livelli di ansia basale influenzano la capacit\ue0 dei soggetti di attuare un determinato compito, anche cognitivo. Tuttavia la suscettibilit\ue0 individuale, all\u2019interno di uno stesso ceppo di ratti na\uefve, \ue8 ancora poco studiata. Lo scopo di questo studio quindi \ue8 stato quello di valutare le possibili differenze interindividuali nel livello d\u2019ansia, all\u2019interno di una popolazione di ratti appartenenti al ceppo Wistar, e di fornire indicazioni su come uno specifico tratto d\u2019ansia possa influenzare una successiva performance cognitiva, valutata mediante un test cognitivo ampiamente utilizzato, il Novel Object Recognition (NOR) test. Seguendo questa linea di ricerca poi, abbiamo voluto indagare se il tratto di ansia potesse influenzare la suscettibilit\ue0 del ceppo di topo C57Bl/6J all\u2019insorgenza dell\u2019 epilessia, e se l\u2019esposizione ad un fattore fortemente stressogeno per il topo, l\u2019odore di un suo predatore, potesse provocare un aggravamento della malattia durante la fase cronica. Questo lavoro di tesi mostra come esista una variabilit\ue0 interindividuale all\u2019interno di una popolazione di roditori per quanto riguarda l\u2019ansia di tratto, cio\ue8 la componente basale di ansia insita in ogni individuo. Questo fattore pu\uf2 influenzare la risposta ad alcuni compiti a cui l\u2019animale deve rispondere, come ad esempio quelli cognitivi. Il tratto d\u2019ansia basale potrebbe anche influenzare la predisposizione all\u2019insorgenza di una determinata malattia, oppure il decorso della malattia stessa. E\u2019 perci\uf2 molto importante considerare il tratto d\u2019ansia basale di ciascun soggetto sperimentale in tutti gli studi che prevedano una componente comportamentale, includendo tale dato come fattore covariato nelle analisi statistiche, cos\uec da evitare errori dovuti a questa variabile nascosta.Human subjects display a great variability in the predisposition to respond anxiogenically to stimuli, i.e. trait anxiety. This susceptibility has been studied in rodents through the creation of selected strains for anxiety-like behaviour, to obtain extreme anxiety traits. Moreover, anxiety has been shown to variously affect physiological processes, such as a cognitive task performance, both in humans and selected rodents strains. However, interindividual differences in basal anxiety level in na\uefve rats and how they may affect cognitive functioning have been poorly investigated. Therefore, the aim of this study is to provide an evidence of the huge interindividual differences in anxiety levels in a population of na\uefve Wistar rats and demonstrate how they can affect a widely used cognitive test, the Novel Object Recognition (NOR) test. Following this line of research, in this study we also investigate if trait anxiety could affect pathological processes, such as the susceptibility on the onset of a neurological disease, the temporal lobe epilepsy, in a population of C57Bl/6J mice. Finally, we evaluate if the exposure to a strong stressful factor for mice, such as a predator odor, could induce an increase of the pathological process in chronic phase of the illness, for example in the number of seizures, in the same epileptic animals. These results could show the relevance to consider trait anxiety, the propension to response in a manner more or less anxious to a specific stimulus, of each subject, in order to avoid interpretative errors during the evaluation of a specific behaviour shown by the subject. Therefore we claim the need to consider interindividual differences in emotionality (e.g. anxiety) in general, and the need to assess anxiety level while studying rats cognitive abilities. It will be possible to include it as a covariate in the statistical analysis, in studies that schedule behavioural factors, in order to avoid interpretative errors dued to this hidden variable

Publisher Correction: Intercalation events visualized in single microcrystals of graphite.

The Peer Review File associated with this Article was updated shortly after publication to redact confidential comments to the editor

The 8.2 ka cooling event caused by Laurentide ice saddle collapse

The 8.2 ka event was a period of abrupt cooling of 1–3 °C across large parts of the Northern Hemisphere, which lasted for about 160 yr. The original hypothesis for the cause of this event has been the outburst of the proglacial Lakes Agassiz and Ojibway. These drained into the Labrador Sea in ∼0.5–5 yr and slowed the Atlantic Meridional Overturning Circulation, thus cooling the North Atlantic region. However, climate models have not been able to reproduce the duration and magnitude of the cooling with this forcing without including additional centennial-length freshwater forcings, such as rerouting of continental runoff and ice sheet melt in combination with the lake release. Here, we show that instead of being caused by the lake outburst, the event could have been caused by accelerated melt from the collapsing ice saddle that linked domes over Hudson Bay in North America. We forced a General Circulation Model with time varying meltwater pulses (100–300 yr) that match observed sea level change, designed to represent the Hudson Bay ice saddle collapse. A 100 yr long pulse with a peak of 0.6 Sv produces a cooling in central Greenland that matches the 160 yr duration and 3 °C amplitude of the event recorded in ice cores. The simulation also reproduces the cooling pattern, amplitude and duration recorded in European Lake and North Atlantic sediment records. Such abrupt acceleration in ice melt would have been caused by surface melt feedbacks and marine ice sheet instability. These new realistic forcing scenarios provide a means to reconcile longstanding mismatches between proxy data and models, allowing for a better understanding of both the sensitivity of the climate models and processes and feedbacks in motion during the disintegration of continental ice sheets