Hyperspectral reflectance from restored tallgrass prairie under different management.

Tallgrass Prairie has been highly fragmented and severely disturbed by overgrazing and land development with most of the tallgrass prairie remnants less than 100 hectares in size. The small size results in increased edge effects, potential invasion by undesirable or exotic species, low genetic diversity in local populations and increased extinction rates. To conserve tallgrass prairie remnants, some types of active management are needed. The most common management methods are prescribed burning, haying and mowing. It is essential to monitor the status of tallgrass prairie in order to determine if management objectives are being met. In this study, close-range hyperspectral remote sensing was used to distinguish spectral reflectance patterns of tallgrass prairie managed under different management regimes. Datasets were collected on July 13, 2001 and again on August 28, 2001. A total of five different treatments were examined at a restored tallgrass prairie near Mead, Nebraska. Regression analysts using dummy variables was utilized to compare between treatments in terms of red edge position and reflectance values in the red and near-infrared regions of the electromagnetic spectrum. It was not possible to distinguish between all treatments based on the location of the red edge. By examining the spectral values in the near infrared it was possible to differentiate between all treatments

Voter model on a directed network: Role of bidirectional opinion exchanges

The voter model with the node update rule is numerically investigated on a directed network. We start from a directed hierarchical tree, and split and rewire each incoming arc at the probability $p$. In order to discriminate the better and worse opinions, we break the $Z_2$ symmetry ($\sigma = \pm 1$) by giving a little more preference to the opinion $\sigma = 1$. It is found that as $p$ becomes larger, introducing more complicated pattern of information flow channels, and as the network size $N$ becomes larger, the system eventually evolves to the state in which more voters agree on the better opinion, even though the voter at the top of the hierarchy keeps the worse opinion. We also find that the pure hierarchical tree makes opinion agreement very fast, while the final absorbing state can easily be influenced by voters at the higher ranks. On the other hand, although the ordering occurs much slower, the existence of complicated pattern of bidirectional information flow allows the system to agree on the better opinion.Comment: 5 pages, 3 figures, Phys. Rev. E (in press

Distribution of Korean Family Names

The family name distribution in Korea is investigated in comparison with previous studies in other countries. In Korea, both the family name and its birthplace, where the ancestor of the family originated, are commonly used to distinguish one family name from the others. The family name distributions with and without the information of the regional origins are analyzed by using different data sets of various sizes, and compared with previous studies performed in other countries. The growth rate of the family is empirically obtained. Contrary to commonly used assumptions, the growth rate is found to be higher for the smaller family.Comment: 13 pages in one column forma

A Wireless Power Transfer Based Implantable ECG Monitoring Device

Implantable medical devices (IMDs) enable patients to monitor their health anytime and receive treatment anywhere. However, due to the limited capacity of a battery, their functionalities are restricted, and the devices may not achieve their intended potential fully. The most promising way to solve this limited capacity problem is wireless power transfer (WPT) technology. In this study, a WPT based implantable electrocardiogram (ECG) monitoring device that continuously records ECG data has been proposed, and its effectiveness is verified through an animal experiment using a rat model. Our proposed device is designed to be of size 24 x 27 x 8 mm, and it is small enough to be implanted in the rat. The device transmits data continuously using a low power Bluetooth Low Energy (BLE) communication technology. To charge the battery wirelessly, transmitting (Tx) and receiving (Rx) antennas were designed and fabricated. The animal experiment results clearly showed that our WPT system enables the device to monitor the ECG of a heart in various conditions continuously, while transmitting all ECG data in real-time.11Ysciescopu