Student perceptions of computer-mediated communication tools in online learning: Helpfulness and effects on teaching, social, and cognitive presence

Distance learning continues to be used in the context of teacher training in special education. Distance learning is experienced through computer-mediated communication (CMC) tools via the Internet, or online learning. Little research has been done to evaluate student perceptions of the helpfulness of CMC tools in online learning. This quantitative study utilizes an online survey of graduate and certification teachers in training for special education. The survey evaluates student perceptions of CMC tool helpfulness, social presence, teaching presence and cognitive presence. Descriptive and inferential statistical analyses are used to evaluate mean differences for different combinations of CMC tool usage and for possible relationships between tool helpfulness and social or teaching presence. Additional demographic variables of gender, level of study, registration status, concentration of study, prior online courses taken and years of teaching experience are also evaluated for possible relationships with social, teaching, and cognitive presence. Results suggest that participants were comfortable with using CMC tools and perceived e-mail, discussion forums, news forums, web-conferencing, and text chat as helpful tools for social and teaching presence communications. Participants using discussion forums perceived higher teaching and cognitive presence than those using only web-conferencing. Participants using both discussion forums and web-conferencing perceived higher cognitive presence than those using only web-conferencing. Results of standard multiple regressions indicated that 31% of the variance in teaching presence (24% of variance in social presence) was accounted for by knowing helpfulness scores on e-mail, discussion forums, and news forums. Discussion forums were most helpful for promoting teaching presence. E-mail was most helpful for promoting social presence. There were no statistically significant mean differences among groups based on gender, level of study, registration status, concentration of study, or years of teaching experience. Results suggest that perceptions of teaching and cognitive presence may decline as the number of online courses taken increases

Multi-band Superconductivity in the Chevrel Phases SnMo6S8 and PbMo6S8

Sub-Kelvin scanning tunnelling spectroscopy in the Chevrel Phases SnMo6S8 and PbMo6S8 reveals two distinct superconducting gaps with Delta_1 = 3 meV, Delta_2 ~ 1.0 meV and Delta_1 = 3.1 meV, Delta_2 ~ 1.4 meV respectively. The gap distribution is strongly anisotropic, with Delta_2 predominantly seen when scanning across unit-cell steps on the (001) sample surface. The spectra are well-fitted by an anisotropic two-band BCS s-wave gap function. Our spectroscopic data are confirmed by electronic heat capacity measurements which also provide evidence for a twin-gap scenario.Comment: 5 pages, 4 figure

Superconducting transitions of intrinsic arrays of weakly coupled one-dimensional superconducting chains: the case of the extreme quasi-1D superconductor Tl(2)Mo(6)Se(6)

International audienceTl(2)Mo(6)Se(6) represents a model system for quasi-one-dimensional (quasi-1D) superconductors. We investigate its superconducting transition in detail by means of electrical transport experiments on high-quality single crystalline samples with onset T(c) = 6.8 K. Our measurements indicate a highly complex superconducting transition that occurs in different stages, with a characteristic bump in the resistivity and distinct plateau structures in the supercurrent gap imaged by V-I curves. We interpret these features as fingerprints of the gradual establishment of global phase coherence in an array of weakly coupled parallel 1D superconducting bundles. In this way, we demonstrate that superconducting Tl(2)Mo(6)Se(6) behaves like an intrinsic array of proximity or Josephson junctions, undergoing a complex superconducting phase-ordering transition at 4.5 K that shows many similarities to the Berezinskii-Kosterlitz-Thouless transition

COVID-19 in Northeast Bosnia and Herzegovina and patient’s length of hospitalization

BACKGROUND: Since the outbreak of COVID-19 pandemic, clinical data from various parts of the world have been reported. Up till now, there has been no clinical data with regards to COVID-19 from Bosnia and Herzegovina (B&H). The aim was to report on the first cohort of patients from B&H and to analyze factors that influence COVID-19 patient’s length of hospitalization (LOH). METHODS: This retrospective cohort study was conducted at Tuzla University Clinical Center (UKC), B&H. It involved 25 COVID-19 positive patients that needed hospitalisation between March 28th and April 27th 2020. The LOH was measured from the time of admission to discharge. Factors analyzed induced age, BMI, presence of known comorbidities, serum creatinine and O2 saturation upon admission. RESULTS: The mean age was 52.92 ± 19.15 years and BMI 28.80 ± 4.22. LOH for patients with BMI < 25 was 9 ± SE2.646 days (CI 95% 3.814–14.816) vs 14.182 ± SE .937 (CI 95% 12.346–16.018 p < 0.05; HR 5.148 CI95% 1.217 to 21.772 p = 0.026) for ≥25 BMI. The mean LOH of patients with normal levels of O2 ≥ 95% was 11.667 ± SE1.202 (CI95% 8.261 to 13.739; p = 0.046), while LOH for patients with < 95% was 14.625 ± SE 1.231 CI95% 12.184 to 16.757 p = 0.042; HR 3.732 CI95%1.137–12.251 p = 0.03). Patients without known comorbidities had a mean LOH of 11.700 ± SE1.075 (CI 95% 9.592–13.808), while those with comorbidities had a mean of 14.8 ± 1.303 (CI 95% 12.247–17.353; p = 0.029) with HR2.552. CONCLUSION: LOH varied among COVID-19 patients and was prolonged when analyzed for BMI ≥25, comorbidities, elevated creatinine, and O2 saturation < 95%. Furthermore, risk factors for COVID-19 patients in B&H do not deviate from those reported in other countries

Sentiment analysis in English texts

The growing popularity of social media sites has generated a massive amount of data that attracted researchers, decision-makers, and companies to investigate people’s opinions and thoughts in various fields. Sentiment analysis is considered an emerging topic recently. Decision-makers, companies, and service providers as well-considered sentiment analysis as a valuable tool for improvement. This research paper aims to obtain a dataset of tweets and apply different machine learning algorithms to analyze and classify texts. This research paper explored text classification accuracy while using different classifiers for classifying balanced and unbalanced datasets. It was found that the performance of different classifiers varied depending on the size of the dataset. The results also revealed that the Naive Byes and ID3 gave a better accuracy level than other classifiers, and the performance was better with the balanced datasets. The different classifiers (K-NN, Decision Tree, Random Forest, and Random Tree) gave a better performance with the unbalanced datasets

Phonon Mode Spectroscopy, Electron-Phonon Coupling and the Metal-Insulator Transition in Quasi-One-Dimensional M2Mo6Se6

We present electronic structure calculations, electrical resistivity data and the first specific heat measurements in the normal and superconducting states of quasi-one-dimensional M2Mo6Se6 (M = Tl, In, Rb). Rb2Mo6Se6 undergoes a metal-insulator transition at ~170K: electronic structure calculations indicate that this is likely to be driven by the formation of a dynamical charge density wave. However, Tl2Mo6Se6 and In2Mo6Se6 remain metallic down to low temperature, with superconducting transitions at Tc = 4.2K and 2.85K respectively. The absence of any metal-insulator transition in these materials is due to a larger in-plane bandwidth, leading to increased inter-chain hopping which suppresses the density wave instability. Electronic heat capacity data for the superconducting compounds reveal an exceptionally low density of states DEF = 0.055 states eV^-1 atom^-1, with BCS fits showing 2Delta/kBTc >= 5 for Tl2Mo6Se6 and 3.5 for In2Mo6Se6. Modelling the lattice specific heat with a set of Einstein modes, we obtain the approximate phonon density of states F(w). Deconvolving the resistivity for the two superconductors then yields their electron-phonon transport coupling function a^2F(w). In Tl2Mo6Se6 and In2Mo6Se6, F(w) is dominated by an optical "guest ion" mode at ~5meV and a set of acoustic modes from ~10-30meV. Rb2Mo6Se6 exhibits a similar spectrum; however, the optical phonon has a lower intensity and is shifted to ~8meV. Electrons in Tl2Mo6Se6 couple strongly to both sets of modes, whereas In2Mo6Se6 only displays significant coupling in the 10-18meV range. Although pairing is clearly not mediated by the guest ion phonon, we believe it has a beneficial effect on superconductivity in Tl2Mo6Se6, given its extraordinarily large coupling strength and higher Tc compared to In2Mo6Se6.Comment: 16 pages, 13 figure

Anthropometry for WorldSID A World-Harmonized Midsize Male Side Impact Crash Dummy

The WorldSID project is a global effort to design a new generation side impact crash test dummy under the direction of the International Organization for Standardization (ISO). The first WorldSID crash dummy will represent a world-harmonized mid-size adult male. This paper discusses the research and rationale undertaken to define the anthropometry of a world standard midsize male in the typical automotive seated posture. Various anthropometry databases are compared region by region and in terms of the key dimensions needed for crash dummy design. The Anthropometry for Motor Vehicle Occupants (AMVO) dataset, as established by the University of Michigan Transportation Research Institute (UMTRI), is selected as the basis for the WorldSID mid-size male, updated to include revisions to the pelvis bone location. The proposed mass of the dummy is 77.3kg with full arms. The rationale for the selected mass is discussed. The joint location and surface landmark database is appended to this paper

Waterpipe Tobacco Smoking and Susceptibility to Cigarette Smoking Among Young Adults in the United States, 2012?2013

Introduction Waterpipe tobacco smoking, also known as hookah and shisha, has surged in popularity among young people in the United States. Waterpipe is also increasingly becoming the first tobacco product that young people try. Given the limited access to and limited portability of waterpipes, waterpipe smokers who become more nicotine dependent over time may be more likely to turn to cigarettes. This study examined the relationship between waterpipe tobacco smoking and susceptibility to cigarette smoking among young adults in the United States. Methods Using data from the 2012?2013 National Adult Tobacco Survey, a nationally representative sample of US adults, we reported rates of current waterpipe smoking and susceptibility to cigarette smoking by demographic characteristics and by use of other tobacco products among survey participants aged 18 to 24 years. Multivariable logistic regression was used to examine the relationship between current waterpipe smoking and susceptibility to cigarette smoking, defined as the lack of a firm intention not to smoke soon or within the next year. Results Of 2,528 young adults who had never established cigarette smoking, 15.7% (n = 398) reported being waterpipe smokers (every day or some days [n = 97; 3.8%] or rarely [n = 301; 11.9%]); 44.2% (176/398) of waterpipe smokers reported being susceptible to cigarette smoking. Those who smoked waterpipe rarely were 2.3 times as susceptible to cigarette smoking as those who were not current waterpipe smokers (OR = 2.3; 95% CI, 1.6?3.4). Conclusion Current waterpipe smoking is associated with susceptibility to cigarette smoking among young adults in the United States. Longitudinal studies are needed to demonstrate causality between waterpipe smoking and initiation of cigarette smoking