The Formation of IRIS Diagnostics. IX. The Formation of the C I 135.58 Line in the Solar Atmosphere

The C I 135.58 line is located in the wavelength range of NASA's Interface Region Imagin Spectrograph (IRIS) small explorer mission. We here study the formation and diagnostic potential of this line by means of non local-thermodynamic-equilibrium modeling, employing both 1D and 3D radiation-magnetohydrodynamic models. The C I/C II ionization balance is strongly influenced by photoionization by Ly-alpha emission. The emission in the C I 135.58 line is dominated by a recombination cascade and the line forming region is optically thick. The Doppler shift of the line correlates strongly with the vertical velocity in its line forming region, which is typically located at 1.5 Mm height. With IRIS the C I 135.58 line is usually observed together with the O I 135.56 line, and from the Doppler shift of both lines, we obtain the velocity difference between the line forming regions of the two lines. From the ratio of the C I/O I line core intensity, we can determine the distance between the C I and the O I forming layers. Combined with the velocity difference, the velocity gradient at mid-chromospheric heights can be derived. The C I/O I total intensity line ratio is correlated with the inverse of the electron density in the mid-chromosphere. We conclude that the C I 135.58 line is an excellent probe of the middle chromosphere by itself, and together with the O I 135.56 line the two lines provide even more information, which complements other powerful chromospheric diagnostics of IRIS such as the Mg II h and k lines and the C II lines around 133.5 nm

MuseGAN: Multi-track Sequential Generative Adversarial Networks for Symbolic Music Generation and Accompaniment

Generating music has a few notable differences from generating images and videos. First, music is an art of time, necessitating a temporal model. Second, music is usually composed of multiple instruments/tracks with their own temporal dynamics, but collectively they unfold over time interdependently. Lastly, musical notes are often grouped into chords, arpeggios or melodies in polyphonic music, and thereby introducing a chronological ordering of notes is not naturally suitable. In this paper, we propose three models for symbolic multi-track music generation under the framework of generative adversarial networks (GANs). The three models, which differ in the underlying assumptions and accordingly the network architectures, are referred to as the jamming model, the composer model and the hybrid model. We trained the proposed models on a dataset of over one hundred thousand bars of rock music and applied them to generate piano-rolls of five tracks: bass, drums, guitar, piano and strings. A few intra-track and inter-track objective metrics are also proposed to evaluate the generative results, in addition to a subjective user study. We show that our models can generate coherent music of four bars right from scratch (i.e. without human inputs). We also extend our models to human-AI cooperative music generation: given a specific track composed by human, we can generate four additional tracks to accompany it. All code, the dataset and the rendered audio samples are available at https://salu133445.github.io/musegan/ .Comment: to appear at AAAI 201

Computer-aided Diagnosis in Breast Ultrasound

Cancer remains a leading cause of death in Taiwan, and the prevalence of breast cancer has increased in recent years. The early detection and diagnosis of breast cancer is the key to ensuring prompt treatment and a reduced death rate. Mammography and ultrasound (US) are the main imaging techniques used in the detection of breast cancer. The heterogeneity of breast cancers leads to an overlap in benign and malignant ultrasonography images, and US examinations are also operator dependent. Recently, computer-aided diagnosis (CAD) has become a major research topic in medical imaging and diagnosis. Technical advances such as tissue harmonic imaging, compound imaging, split screen imaging and extended field-of-view imaging, Doppler US, the use of intravenous contrast agents, elastography, and CAD systems have expanded the clinical application of breast US. Breast US CAD can be an efficient computerized model to provide a second opinion and avoid interobserver variation. Various breast US CAD systems have been developed using techniques which combine image texture extraction and a decision-making algorithm. However, the textural analysis is system dependent and can only be performed well using one specific US system. Recently, several researchers have demonstrated the use of such CAD systems with various US machines mainly for preprocessing techniques designed to homogenize textural features between systems. Morphology-based CAD systems used for the diagnosis of solid breast tumors have the advantage of being nearly independent of either the settings of US systems or different US machines. Future research on CAD systems should include pathologically specific tissue-related and hormonerelated conjecture, which could be applied to picture archiving and communication systems or teleradiology

Studies on Irradiation and Electric Potential Effects toward Mineral Atomic Structure and Chemical Reactivity

First, we focus on the effect of neutron irradiation on the durability of silicate and carbonate mineral aggregates. Comparisons of mineral dissolution rates, as a function of pH, temperature, or surface potential, were performed at pristine or Ar+ ion irradiated state. The experimental results were coupled with MD simulations of atomic scale alteration in the crystallographic structure of the mineral and any resulting changes in physical properties that result. In detail, albite (NaAlSi3O8), a 3D framework silicate, is compared with a less polymerized silicate (i.e., almandine) and carbonates (e.g. calcite, and dolomite), which are also often present in the mineral aggregates that compose concrete. When exposed to radiation, the crystal structures of minerals have possibilities to undergo significant alterations. These alterations may perhaps enhance its chemical durability, and thus degrade the infrastructure durability. This relatively higher enhancement in the dissolution rate of silicates compared to carbonates following irradiation has significant impacts on the durability of concrete containing them up on their exposure to radiation in nuclear power plant environments. Second, the effect of electric potential to calcite dissolution kinetics is examined. The accelerated ion transportation by potential further enhances calcite dissolution, whereas the extent of induced dissolution depends on the pH, ionic strength, and temperature. Calcite dissolution rate is enhanced in acidic to neutral pH solution, but remains constant in alkaline pH. From this, it reveals that the potential-induced dissolution rates are governed by the rate-limiting step in the dissolution mechanism. In addition, by varying solution ionic strength, stronger ionic strength results in less dissolution rate enhancement due to the lower ion diffusivity. As from the examination of the temperature effect, the potential-induced dissolution rate enhancement shows that electric potential does not increase calcite dissolution rate significantly compared to temperature. In sum, it can be concluded that the mineral chemical reactivity can be enhanced by introducing external stimulus, and the magnitude of the rate enhancement depends highly on the solid atomic structure and the solvent properties. The conclusion and proposed future perspective of these works can be helpful to enhance the durability of concrete infrastructures and the relevant engineering applications

Occupation, Dispersal, and Economic Impact of Major Invasive Plant Species in Southern U.S. Forests

Invasive alien plants have impacted southern U.S. forests. This study focuses on quantifying current distribution, rate of dispersals, and economic losses caused by four major invaders — Chinese tallow (Triadica sebifera (L.) Small), Chinese Privet (Ligustrum sinense Lour.), European Privet (Ligustrum vulgare L.), and Japanese Honeysuckle (Lonicera japonica Thunb.). Using data from USDA Forest Service’s Forest Inventory and Analysis (FIA), National Oceanic and Atmospheric Administration (NOAA), and USGS Land Use and Land Cover (LULC), I first used logistic regressions to build occupation models for these four species. Second, I used VB.NET© (Microsoft, 2003) and Environment System Research Institute (ESRI) Arc View® 9.2 Geographical Information System (GIS) to model spatially explicit dispersal dynamics of these species. Finally, I evaluated economic losses associated with these invasions. The results of occupation models showed that landscape features, climatic conditions, forest and site conditions, forest management activities and disturbances, and forest ownership have statistically significant impacts on current distributions of all four species. The results of dispersal models showed that invasions of Chinese tallow, Chinese and European privets, and Japanese honeysuckle will be likely to appear on approximately 6.65 million acres of forest land in East Texas and Louisiana, 3.81 million acres in Mississippi and Alabama, and 12.55 million acres in Mississippi and Alabama, respectively, during the next 20 years. The estimated timber losses resulting from the invasion with no control for the next 20 years at 5% discount rate is 518 million dollars for Chinese tallow, 2.72 billion dollars for Chinese and European privets, and 11.05 billion dollars for Japanese honeysuckle. From an economic point of view, it would be most cost effective to execute high intensity control for these invasive species. Based on these findings, strategies for monitoring and mitigating these invasive species are proposed