Visibility of disjoint polygons

Consider a collection of disjoint polygons in the plane containing a total ofn edges. We show how to build, inO(n ²) time and space, a data structure from which inO(n) time we can compute the visibility polygon of a given point with respect to the polygon collection. As an application of this structure, the visibility graph of the given polygons can be constructed inO(n ²) time and space. This implies that the shortest path that connects two points in the plane and avoids the polygons in our collection can be computed inO(n ²) time, improving earlierO(n ² logn) results.     

Characteristics of THz-wave radiation using a monolithic grating coupler on a LiNbO3 crystal

Wide tunable terahertz (THz) wave generation was successfully demonstrated utilizing a grating coupler fabricated on the surface of a LiNbO₃ crystal which was pumped by a Q-switched Nd:YAG laser. In this paper, we report the detailed characteristics of the oscillation and the radiation including tunability, spatial and temporal coherency, directivity, and efficiency. Oscillation using a LiTaO₃ crystal was also performed, in which experimental phasematching condition values agreed well with the calculated one.     

Collapsin response mediator protein-2 is associated with neurofibrillary tangles in Alzheimer's disease

Intraneuronal accumulation of paired helical filaments (PHF) is considered to be closely related to the neuronal loss observed in brains of patients affected with Alzheimer's disease. The central issue is whether PHF formation itself causes or accelerates the neuronal perikaryal and neuritic degeneration or whether they are simply the consequence of preceding degeneration. We sought to address the issue in part by characterizing the PHF-associated molecules and thus raised a number of monoclonal antibodies to neurofibrillary tangles. One monoclonal antibody, 3F4, strongly reacted with neurofibrillary tangles and some plaque neurites but few neuropil threads. This monoclonal antibody labeled a 65-kDa protein, but not tau or ubiquitin, on a Western blot of human brain extract and immunoprecipitated the same protein. The peptides released from the purified 65-kDa protein had the same sequences as those of a newly identified protein, human collapsin response mediator protein-2. Incorporation into neurofibrillary tangles may deplete soluble, cytosolic human collapsin response mediator protein-2 and lead to abnormal neuritic and/or axonal outgrowth of the tangle-bearing neuron, thus accelerating the neuritic degeneration in Alzheimer's disease.     

A cross-validation of the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC QLQ-C30) for Japanese with lung cancer

The EORTC QLQ-C30 was developed in English-speaking cultures. To determine if this instrument could cross a broad cultural divide and be used in Japan, the cross-cultural validity of its Japanese version was estimated. In evaluating psychometric testing, internal consistency by Cronbach's alpha, item-discrimination by multitrait scaling analysis, and validity analysis with ECOG performance score (PS) and Karnofsky Performance Status Scale (KPS) were performed. The QLQ-C30 (version 1.0) was given to 105 patients with lung cancer. Although the response rate was low in patients with PS 4, the questionnaire was well accepted by patients with PS 0-3. The Japanese QLQ-C30 has a weak scale of role functioning in terms of item discriminative validity. It also has a weak scale of cognitive functioning in items of discriminative validity and internal consistency. However, known-groups comparison showed the expected clinical validity with PS for all the scales except for financial impact, and longitudinally clinical validity with KPS was shown in scales of cognitive functioning, fatigue, and nausea and vomiting. Multitrait scaling analysis showed that the predicted scales constituting quality of life (QOL) in the English-speaking culture were extracted from the Japanese QLQ-C30, and found to be valid in Japan, indicating its possible usefulness as an instrument that is universally applicable across cultures.     

The internal thoracic artery of poor quality: was cardiac massage a cause of ITA stenosis?

The case of stenotic left internal thoracic artery (LITA), with a very rare and interesting histological findings is reported. The patient, a 65-year-old man, fell into shock, due to acute myocardial infarction and received cardiopulmonary resuscitation at home immediately. Three months later, patient underwent coronary artery bypass grafting. The LITA was dissected from the chest wall with a tissue pedicle by usual manner. However, it was abandoned to use for grafting, because of extremely poor blood flow even after balloon dilatation was noticed. Histological study revealed a significant granulation of LITA media, led to severe stenosis of LITA lumen on it's portion. On other side, either proximal and distal portion of LITA remained intact. It seems that this unusual histological change of LITA media developed after LITA over stretching due to cardiac massage during cardiopulmonary resuscitation. If patient, scheduled for coronary bypass surgery, has in a personal history the presence of cardiac massage, traffic accident, some contact sport or any other chest trauma, it is recommended to perform LITA angiography preoperatively, if an intention to use the LITA for coronary artery bypass grafting exists.     

Development of a substation digital protection and control systemusing fiber-optic local area network

A substation protection and control system was developed and has been under trial use at a 50 kV substation. The system's digital protection and control equipment are located close to the outdoor power apparatus, and they are linked by an optical local area network (LAN). An IEEE 802.4 token-passing bus was used as the protocol of the LAN system. Optical star couplers were used for the physical layer. A specially designed synchronous sampling mechanism is also applied to the token bus to make the system more effective. Three manufacturers fabricated terminal equipment, which was linked by the optical LAN. Their interoperability was verified     

Propagation measurements and models for wireless communicationschannels

The authors describe the type of signals that occur in various environments and the modeling of the propagation parameters. Models are essentially of two classes. The first class consists of parametric statistical models that on average describe the phenomenon within a given error. They are simple to use, but relatively coarse. In the last few years a second class of environment-specific models has been introduced. These models are of a more deterministic nature, characterizing a specific street, building, etc. They are necessarily more time consuming to use, but are also more revealing concerning physical details and hopefully more accurate. Some key parameters and the measurement of them are discussed and then the different wireless environments are treated. The latter topic is divided into outdoor environments, indoor environments, and radio penetration from outdoor to indoor environments