Optical Conductivity of Weyl Semimetals and Signatures of the Gapped Semimetal Phase Transition

The interband optical response of a three-dimensional Dirac cone is linear in photon energy ($\Omega$). Here, we study the evolution of the interband response within a model Hamiltonian which contains Dirac, Weyl and gapped semimetal phases. In the pure Dirac case, a single linear dependence is observed, while in the Weyl phase, we find two quasilinear regions with different slopes. These regions are also distinct from the large-$\Omega$ dependence. As the boundary between the Weyl (WSM) and gapped phases is approached, the slope of the low-$\Omega$ response increases, while the photon-energy range over which it applies decreases. At the phase boundary, a square root behaviour is obtained which is followed by a gapped response in the gapped semimetal phase. The density of states parallels these behaviours with the linear law replaced by quadratic behaviour in the WSM phase and the square root dependence at the phase boundary changed to $|\omega|^{3/2}$. The optical spectral weight under the intraband (Drude) response at low temperature ($T$) and/or small chemical potential ($\mu$) is found to change from $T^2$ ($\mu^2$) in the WSM phase to $T^{3/2}$ ($|\mu|^{3/2}$) at the phase boundary.Comment: 11 pages, 6 figure

Explosion bills of materials of products in information systems of a production enterprise

The paper presents algorithms for the listing of information on bills of materials for assembled products. Bills of materials were distinguished into explosions: single-level, multi-level and aggregate. Bills of materials were developed using the concepts of the master and slave components. Proposed algorithms for information gathering may be coded in selected programming languages and in this form used in data bases supporting production management processes in industrial enterprises manufacturing assembled products. Application of algorithms was illustrated using an example of a furniture product

Perceived Health Status and Needs of Elders of the Spirit Lake Nation

Chronic disease inflicts a huge financial and collective burden on the people of this nation. Disparities in chronic disease and health risk behaviors do exist for Native Americans. The multiple disparities of the Spirit Lake Nation are identified through the use of the survey tool that was developed by the National Resource Center of Native American Aging. The quantitative descriptive study collected self-reported data related to perceived health status, behavioral risk factors, chronic disease, and other demographic information among the Spirit Lake Nation elders. A health promotion and disease prevention model that influences self care appeared to be the most applicable for this study; thus Pender’s Health Promotion model was chosen as the most appropriate. Pender’s Model is multidimensional and holistic in perspective, and similar to the traditional concept of health in Native American people. Pender’s Model is also based on the nature of persons interacting with their environment as they pursue health. The primary assumption is that individuals have an active role in shaping and maintaining health behaviors and modifying the environmental content for health behaviors. Upon evaluating the data that was obtained through the survey, diabetes was identified as a chronic condition which significantly impacted on the people of the Spirit Lake Nation. Nearly 45% of the elders identified diabetes as a self-reported chronic illness (compared to 14.6% nationally). The literature indicated that diabetes is greatly influenced by behavioral risk factors, thus diet, exercise, and nutrition have a critical impact on the disease process and/or the complications associated with diabetes. Anecdotal information indicates that diabetes has an enormous impact on entire families at Spirit Lake. Family and community education regarding diabetes is needed in order to promote positive outcomes in the community. The “Talking Circle” model is recommended as the teaching method for education in this community. The “Talking Circle” model promotes small group community/family interactive education, promoting participant control of the learning environment in a comfortable and informal process. This process will promote an individual’s active role in shaping and maintaining their own health behaviors and promoting modification of their environment for positive health outcomes

Objective Assessment of Olfactory Function Using Functional Magnetic Resonance Imaging=Estudio objetivo del olfato mediante resonancia magnética funcional

Objective: To show the results of a device that generates automated olfactory stimuli suitable for functional magnetic resonance imaging (fMRI) experiments. Material and methods: Te n normal volunteers, 5 women and 5 men, were studied. The system allows the programming of several sequences, providing the capability to synchronise the onset of odour presentation with acquisition by a trigger signal of the MRI scanner. The olfactometer is a device that allows selection of the odour, the event paradigm, the time of stimuli and the odour concentration. The paradigm used during fMRI scanning consisted of 15-s blocks. The odorant event took 2 s with butanol, mint and coffee. Results: We observed olfactory activity in the olfactory bulb, entorhinal cortex (4%), amygdala (2.5%) and temporo-parietal cortex, especially in the areas related to emotional integration. Conclusions: The device has demonstrated its effectiveness in stimulating olfactory areas and its capacity to adapt to fMRI equipment.RESUMEN Objetivo: Mostrar los resultados del olfatómetro capaz de generar tareas olfativas en un equipo de resonancia magnética funcional (fMRI). Material y métodos: Estudiamos 10 sujetos normales: 5 varones y 5 mujeres. El olfatómetro está dise ̃ nado para que el estímulo que produce se sincronice con el equipo de fMRI mediante la se ̃ nal desencadenante que suministra el propio equipo. El olfatómetro es capaz de: selec- cionar el olor, secuenciar los distintos olores, programar la frecuencia y duración de los olores y controlar la intensidad del olor. El paradigma utilizado responde a un dise ̃ no de activación asociada a eventos, en el que la duración del bloque de activación y de reposo es de 15 s. La duración del estímulo olfativo (butanol, menta o café) es de 2 segundos, durante toda la serie que consta de 9 ciclos. Resultados: Se ha observado reactividad (contraste BOLD) en las diferentes áreas cerebrales involucradas en las tareas olfativas: bulbo olfatorio, córtex entorrinal (4%), amigdala (2,5%) y córtex temporoparietal. Las áreas relacionadas con integración de las emociones tienen una reactividad mayor. Conclusiones: El dispositivo propuesto nos permite controlar de forma automática y sincronizada los olores necesarios para estudiar la actividad de las áreas olfatorias cerebrales mediante fMRI