New complexity results for parallel identical machine scheduling problems with preemption, release dates and regular criteria

In this paper, we are interested in parallel identical machine scheduling problems with preemption and release dates in case of a regular criterion to be minimized. We show that solutions having a permutation flow shop structure are dominant if there exists an optimal solution with completion times scheduled in the same order as the release dates, or if there is no release date. We also prove that, for a subclass of these problems, the completion times of all jobs can be ordered in an optimal solution. Using these two results, we provide new results on polynomially solvable problems and hence refine the boundary between P and NP for these problems

Experimental simulation of quantum graphs by microwave networks

We present the results of experimental and theoretical study of irregular, tetrahedral microwave networks consisting of coaxial cables (annular waveguides) connected by T-joints. The spectra of the networks were measured in the frequency range 0.0001-16 GHz in order to obtain their statistical properties such as the integrated nearest neighbor spacing distribution and the spectral rigidity. The comparison of our experimental and theoretical results shows that microwave networks can simulate quantum graphs with time reversal symmetry. In particular, we use the spectra of the microwave networks to study the periodic orbits of the simulated quantum graphs. We also present experimental study of directional microwave networks consisting of coaxial cables and Faraday isolators for which the time reversal symmetry is broken. In this case our experimental results indicate that spectral statistics of directional microwave networks deviate from predictions of Gaussian orthogonal ensembles (GOE) in random matrix theory approaching, especially for small eigenfrequency spacing s, results for Gaussian unitary ensembles (GUE). Experimental results are supported by the theoretical analysis of directional graphs.Comment: 16 pages, 7 figures, to be published in Phys. Rev.

Long-Term Relations Among Prosocial-Media Use, Empathy, and Prosocial Behavior

Despite recent growth of research on the effects of prosocial media, processes underlying these effects are not well understood. Two studies explored theoretically relevant mediators and moderators of the effects of prosocial media on helping. Study 1 examined associations among prosocial- and violent-media use, empathy, and helping in samples from seven countries. Prosocial-media use was positively associated with helping. This effect was mediated by empathy and was similar across cultures. Study 2 explored longitudinal relations among prosocial-video-game use, violent-video-game use, empathy, and helping in a large sample of Singaporean children and adolescents measured three times across 2 years. Path analyses showed significant longitudinal effects of prosocial- and violent-video-game use on prosocial behavior through empathy. Latent-growth-curve modeling for the 2-year period revealed that change in video-game use significantly affected change in helping, and that this relationship was mediated by change in empathy

Internet Gaming Disorder in children and adolescents

The American Psychiatric Association recently included Internet gaming disorder (IGD) as a potential diagnosis, recommending that further study be conducted to help illuminate it more clearly. This paper is a summary of the review undertaken by the IGD Working Group as part of the 2015 National Academy of Sciences Sackler Colloquium on Digital Media and Developing Minds. By using measures based on or similar to the IGD definition, we found that prevalence rates range between ∼1% and 9%, depending on age, country, and other sample characteristics. The etiology of IGD is not well-understood at this time, although it appears that impulsiveness and high amounts of time gaming may be risk factors. Estimates for the length of time the disorder can last vary widely, but it is unclear why. Although the authors of several studies have demonstrated that IGD can be treated, no randomized controlled trials have yet been published, making any definitive statements about treatment impossible. IGD does, therefore, appear to be an area in which additional research is clearly needed. We discuss several of the critical questions that future research should address and provide recommendations for clinicians, policy makers, and educators on the basis of what we know at this time

Cutting Gordian Knots: Reducing Prejudice Through Attachment Security

The positive role of secure attachment in reducing intergroup biases has been suggested in prior studies. We extend this work by testing the effects of secure attachment primes on negative emotions and aggressive behaviors toward outgroup members across four experiments. Results from Studies 1A and 1B reveal that secure attachment prime, relative to neutral, can reduce negative outgroup emotions. In addition, Studies 1B and 3 results rule out positive mood increase as an alternative explanation for the observed effects. Results from Studies 2 and 3 reveal that secure attachment primes can reduce aggressive behavior toward an outgroup member. The effect of secure attachment primes on outgroup harm was found to be fully mediated by negative emotions in Studies 2 and 3. An interaction between secure attachment primes and ingroup identification in Study 2 indicated that the positive effects of secure attachment in reducing outgroup harm may be especially beneficial for highly identified ingroup members

An Experiential Learning Opportunity in Norway: Computation for Bioengineering and Mechanical Engineering Students

The global learning initiative at Northeastern University is focused on fostering intercultural communication skills. The Dialogue of Civilization (DOC) program serves as a mechanism to achieve such a goal by offering faculty-led international experiences. In this paper, we have presented a detailed account of a DOC program that took place in Norway. The primary objective of the program was to teach mechanical engineering and bio-engineering students computational skills while stimulating critical thinking about the cultural and social aspects of technology and engineering in Norway. The program focused on two courses: a technical course and a special topics course. The technical course introduced students to finite element analysis, with practical applications and site visits in Norway to enhance experiential learning. In the special topics course, the interplay between modern technologies, like green energy, state policies, and the rights and traditions of the indigenous Sámi people was explored. The course highlighted both the progressive social policies in Norway and the historical discrimination against the Sámi. Student feedback was positive and experiential learning components such as guest lectures and site visits were particularly appreciated. Additional surveys showed that students' self-confidence was higher following the DOC program. In addition, female-identifying students had higher confidence in their future success after completion of this program as compared to their male-identifying counterparts. Our paper is expected to serve as a resource for educators seeking to integrate technical education with intercultural experiences and discussions on social and cultural impacts in engineering