767 research outputs found
Cadmium Sulfide-Porous Silicon nanocomposite structures
No full textOptimum conditions for the formation of cadmium sulfide nanoparticles in a porous silicon matrix have been determined. The mechanisms of charge transfer in the formed heterostructures and their dependences on the porous layer properties and conditions of CdS nanoparticle synthesis have been studied. The spectral distribution and the intensity of photoluminescence are demonstrated to be governed by the concentration and the size of synthesized CdS nanocrystallites, as well as the efficiency of radiation recombination at deep centers bound with defects. © N.A. DAVIDENKO, G.V. KUZNETSOV, YU.S. MILOVANOV, 2013
Recommended from our members
The nature of subjective control of Illusory Apparent Motion
No full textPolystable phenomena have been extensively studied to understand the constructive nature of perception (e.g., the Necker cube, duck-rabbit, binocular rivalry). A new polystable phenomenon, illusory apparent motion (IAM), with unique properties was recently discovered (Davidenko et al., 2017). IAM is generated in randomly refreshing pixel arrays. As a result, IAM, unlike other polystable phenomena, affords potentially counterless interpretations of the pixel motion and observers may not automatically experience an initial interpretation, instead having to rely on self-generated initial percepts. These unique properties of IAM raise a plethora of questions. In light of IAM’s unique properties, the four experiments presented here explore questions about the nature of subjective control of IAM. Experiments 1 and 2 ask whether observers can mentally control their perception of IAM (a feature common in other polystable phenomena). Experiment 1 explores this question using a motion priming and persistence task, based on the methods of Davidenko et al. (2017). Participants were presented with a series of priming frames that transitioned to frames of pure noise and reported with a single button press when the initial motion pattern appeared to change. Experiment 1 found that observers were able to mentally control IAM, evidenced by extended motion persistence when they were instructed to ‘hold’ and shortened motion persistence when they were instructed to ‘change.’ Experiment 2 explores the same question, but in a methodological context more in line with past subjective controls studies (Kohlers et al., 2008). For this task, participants were not assisted with motion primes, instead self-generating initial motion patterns, and reported their percepts dynamically throughout the trial. Experiment 2 found that participants were able to control their perception of IAM in this new, possibly more demanding, experimental context. Together, the results of Experiments 1 and 2 demonstrate that participants can subjectively control their perceptions of IAM. Experiment 3 explored questions about the potentially countless interpretations of IAM: how many interpretations of IAM can observers perceive and subjectively control? Experiment 3 tested 14 different motion types, half of which were motion types not yet explored in IAM studies (i.e., containing expansion, contraction, and shearing motion patterns). For each trial, participants were informed about one of the 14 motion types of instruction and, for one block, reported when they happened to perceive the instructed motion. In another block, participants were instructed to try and ‘hold’ the instructed motion. Experiment 3 found that observers were able to perceive many and control a few interpretations of IAM, supporting previous assumptions that observers likely experience more interpretations of IAM than other polystable phenomena. The last study, Experiment 4, explored whether it was possible to quantify some of the low- and high-level factors that can influence participants’ perception of IAM (e.g., subjective control, motion biases, motion coherence). To test this, participants were presented with two priming frames, followed by two test frames. The test frames were manipulated to present participants with (1) a nulling (prime-inconsistent) motion below and above their perceptual threshold, (2) with a facilitating (prime-consistent) motion below and above their perceptual threshold, and (3) with 0% motion. After each trial, participants reported the direction of motion that they perceived on the final two frames. Experiment 4 demonstrates that it’s possible to quantify a number of factors, including: the strength of the rebound bias, subjective control, motion nulling, and motion facilitation.Taken together, Experiments 1-4 lay the initial groundwork for exploring subjective control of IAM. Together they demonstrate subjective control in a variety of task conditions, suggest which motion types participants can control, and quantify the strength of subjective control
Recommended from our members
A holistic advantage in face drawing: higher accuracy when drawing upright faces
No full textThis study looks into the conception that drawing or copying a face that is vertically inverted will improve the
accuracy of the drawing by preventing holistic interference. We had participants draw parameterized face profiles (both upright
and inverted) that were sampled from face space (see Davidenko, 2007). In each trial, participants were shown a face on
the left side of the screen and asked to copy it on the right side. We then recorded the location of 66 landmark points on
each face drawing, allowing us to compute a distance metric between each drawing and its corresponding original face. This
distance metric served as a measure of accuracy, with higher distances corresponding to greater errors. Contrary to common
belief, people’s drawings were significantly more accurate for upright versus inverted faces (t(15) = 4.9; p=0.0002). Our results
suggest that holistic processing improves, rather than impairs, the accuracy of face drawing
Tumor Growth Dynamics. A Deterministic and Stochastic Analysis of the Interaction between Normal and Abnormal Cells
No full text13 pages, 1 article*Tumor Growth Dynamics. A Deterministic and Stochastic Analysis of the Interaction between Normal and Abnormal Cells* (Acosta, Brendaliz; Barrera, Jaime H.; Clarke, Ernesto S., II; Davidenko, Nicolas; Ting, Derek) 13 page
Dynamics of a Two-Dimensional Discrete-Time SIS Model
No full text24 pages, 1 article*Dynamics of a Two-Dimensional Discrete-Time SIS Model* (Barrera, Jaime H.; Cintron-Arias, Ariel; Davidenko, Nicolas; Denogean, Lisa; Franco-Gonzalez, Saul R.) 24 page
PREPARATION OF THE PHYSICS TEACHER FOR RECEIVING PHOTOGRAPHS OF THE MOMENTS OF THE FLASHING NATURAL PHENOMENA
No full textThe purpose of the work is to justify the need to prepare teachers of physics and other natural subjects to take photographs of the moments of the course of natural phenomena, which contributes to the expansion of their opportunities in the implementation of the educational process.
The research methodology is based on the Law of Ukraine «On Education», the Concept of Science and Mathematics Education (STEM-education), the requirements of educational programs in science subjects. The author relies on his own long experience of working in the teacher training system, in particular, in the Chernihiv Regional Institute of Postgraduate Pedagogical Education named after K. D. Ushinsky, where he developed and implemented the corresponding author's courses and seminars in the educational process, and created the didactic content, in particular, photographs demonstrated their effectiveness in practice, that is, during training sessions. Photographic materials created by the author are used for setting problems in physics and became the subject of his scientific research, which is reflected in the relevant scientific and scientific-methodological works.
The content of the article is aimed at satisfying the requests of scientists, teachers of institutions of higher education, in particular institutions of postgraduate pedagogical education, teachers who are not indifferent to the problems of educational development.
The scientific novelty of the research lies in the fact that the author proves the necessity and possibility of creating the named didactic materials by direct participants in the educational process, which contributes not only to increasing the effectiveness of education, but also to the development of the creative abilities of the teacher and his students. At the same time, it is shown how to prepare a teacher for such an activity.
The results of the research were reported at international scientific conferences (Republic of Moldova – 2011, 20213, 2019, 2021, 2022; USA – 2022) and others. and implemented in pedagogical practice at Tiraspil State University, Chisinau State University, T. H. Shevchenko National University «Chernihiv Colehium», Chernihiv Regional Institute of Postgraduate Pedagogical Education named after K. D. Ushinskyi.
Conclusions. The educational process in science subjects always requires new technical means and didactic materials. Interesting didactic materials in this regard were and remain photographs of natural phenomena.
Photographic images of individual moments of images of natural phenomena contribute to a deeper insight into their essence, and, therefore, to their better understanding.
The development of modern photo and video technology makes it much easier, compared to the past, to obtain moments of the course of fast-moving phenomena. It is important that the mentioned technical means have become available to wide sections of the population, in particular to teachers and their students.
A significant number of educational photographs can be obtained by the teacher who, more than anyone else, feels the need for them to achieve a specific goal of the corresponding educational session.
Involvement of students in photographing moments of natural phenomena not only contributes to their better assimilation of educational material, but also to the development of their creative abilities.
In order to carry out purposeful training of teachers of physics and other science subjects to create new didactic materials in the form of photographs, appropriate work should be carried out on courses to improve their qualifications
Suicide prevention lifeline will listen: a video advertisement
No full textThe National Suicide Prevention Lifeline is a 24-hour phone toll-free line primarily dedicated to the prevention of suicide and promoting wellbeing. Perhaps unbeknownst to most of the general public, many callers do not require suicide prevention or crisis intervention, and taking calls from these individuals is still an important aspect of the NSPL. In fact, taking such calls further promotes well-being. The NSPL offers the opportunity for interpersonal connections to everyone, at any time, regardless of whether they are suicidal or not. The NSPL responds to anyone???regardless of gender, age, ethnicity, political beliefs, religion, nationality, or sexual orientation???with the only exception being people who misuse the lifeline in a sexually inappropriate manner. People can call, anytime, for free, and talk to a trained phone counselor who will use active listening skills to make the caller feel heard. This project will be the development of a video advertisement that focuses on the compassionate aspect of the suicide prevention hotline and its broad availability
PROBLEMS OF PREPARATION FOR TUTORIALS OF JUNIOR INFANTS AND RATIONALIZERS
No full textThe purpose of the work is to familiarize interested scientists and teachers with the peculiarities and problems of preparing the tasks for the All-Ukrainian tournaments of young inventors and innovators.
The research methodology is based on the concept of working with gifted students, from the provision on the All-Ukrainian Tournament of Young Inventors and Rationalizers (author's project). The survey focused on the requests of tournament organizers and members of its jury, as well as on scholars and teachers who organize work with creatively gifted students. Long experience in preparing such tasks, observing and analyzing video materials obtained during the tournaments, has allowed us to find a tendency to change the requirements to the tasks. Created videos and video games of the tournament allowed not only monitoring, but also providing the educational process with new multimedia.
The scientific novelty of the research is that for the first time the author shows the dynamics of the development of requirements for tasks used in the All-Ukrainian tournaments of young inventors and rationalizers. The results of the study were reported at the scientific conferences of Ukraine, the Republic of Belarus, the Republic of Moldova and the Russian Federation. Taking into account these dynamics and tasks are prepared for all the following tournaments.
Conclusions. The tasks given to the participants of the All-Ukrainian tournaments of young inventors and innovators have their own peculiarities. All such tasks are aimed at creating original devices or technologies. They belong to the category of the most creative tasks and therefore can have a significant number of solutions.
The content of the tasks should be clear to the students and take into account their own inquiries and demands of the community.
Requirements to the tasks vary depending on the modern development of technology and the level of preparation of students.
Our further research will focus on the training of teachers and students to set their own goals, which follows from the author's proposal for a full cycle of creativity in his doctoral dissertation
Suicide prevention lifeline will listen: a video advertisement
No full textThe National Suicide Prevention Lifeline is a 24-hour phone toll-free line primarily dedicated to the prevention of suicide and promoting wellbeing. Perhaps unbeknownst to most of the general public, many callers do not require suicide prevention or crisis intervention, and taking calls from these individuals is still an important aspect of the NSPL. In fact, taking such calls further promotes well-being. The NSPL offers the opportunity for interpersonal connections to everyone, at any time, regardless of whether they are suicidal or not. The NSPL responds to anyone—regardless of gender, age, ethnicity, political beliefs, religion, nationality, or sexual orientation—with the only exception being people who misuse the lifeline in a sexually inappropriate manner. People can call, anytime, for free, and talk to a trained phone counselor who will use active listening skills to make the caller feel heard. This project will be the development of a video advertisement that focuses on the compassionate aspect of the suicide prevention hotline and its broad availability
Recommended from our members
GIF Me a Break: The Influence of Reaction GIFs on Overhearers’ Judgements of Humor and Irony in Computer-Mediated Communication
No full textHumor in face-to-face interactions regularly exploits multimodal cues such as emotional facial expressions as social cognitive tools that help us coordinate our beliefs with others’. The encryption theory of humor (Flamson & Barrett, 2008) states that humorous acts are encrypted and we need a common “key” to understand what’s funny and humor acts a marker of internal similarity. We communicate this shared knowledge with laughter, which denotes affiliative interactions and shared underlying assumptions about the world (e.g., “This is socially okay, so I can believe it’s funny”; Flamson & Bryant, 2013) while cringing away indicates an affective stance of “this is not okay”.These interactions are prevalent in every day face-to-face conversations, but are difficult to express in computer-mediated communication (CMC). However, the regular use and presence of GIFs in online mediums such as text messaging newly affords a similar style of multi-party interactions where one’s commentary on another person’s jokes may change someone’s opinion of the joke and interaction itself. If these multimodal cues exist in face-to-face group interactions, can CMC afford the same socioemotional cuing? GIFs, which re-present looped animations of embodied actions and are commonly used as reactions to everyday occurrences (Herring, 2015) have been found to act as embodied depictions that demonstrate one’s own current reactions in text-messaged conversations (Tolins & Samermit, 2016).With the affordances, the possibilities for action that an agent directly perceives in an object or an environment (Gibson, 1979), provided with GIFs, this dissertation aims to answer the following broad question: How does the presence of a reaction GIF change how funny people perceive “overheard” text-messaged jokes? And does the way the GIF is understood as ironic (a combination of different dimensions of irony, such as how hyperbolic, understated, sarcastic, playful, performative, and humorous people find something; Gibbs & Samermit, 2017) have a predictive relationship with how funny they might find the joke itself?This dissertation addressed these broad question in two experiments. In Experiment 1, participants acted as “overhearers” in a text-messaged group chat where they received a joke from one member of the group, and viewed either another member’s positive or negative GIF response, another member’s positive or negative Text response, or no response at all, before rating how funny they found the joke, and how ironic (sarcastic, hyperbolic, critical, and playful) they found the response. In Experiment 2, participants did the same as Experiment 1, but also saw static or animated GIF or Text responses. The two experiments tested two hypotheses: the passive observer hypothesis, where overhearers do not integrate valence with ironic information into their judgments of humor, and the active negotiator hypothesis, where they do. Results across both experiments support the active negotiator hypothesis, indicating overhearers in text messaged conversations conduct metarepresentational reasoning and integrate valence with ironic information about responses to make judgments of humor. This finding supports the encryption theory of laughter and humor
- …
