Configuration spaces of points on the circle and hyperbolic Dehn fillings

A purely combinatorial compactification of the configuration space of n (>4) distinct points with equal weights in the real projective line was introduced by M. Yoshida. We geometrize it so that it will be a real hyperbolic cone-manifold of finite volume with dimension n-3. Then, we vary weights for points. The geometrization still makes sense and yields a deformation. The effectivity of deformations arisen in this manner will be locally described in the existing deformation theory of hyperbolic structures when n-3 = 2, 3.Comment: 22 pages, to appear in Topolog

Food-System of Tuna Industry: Market Distortions in Canning and Sashimi Markets

In this paper, we illustrate characteristics of food system of tuna by making a bird’s-eye view of tuna trade and global distribution. Tuna resources are primarily consumed as canned tuna or Sashimi (=raw fish). The fishing methods and species predetermine the food system of the caught fish. Among seven tuna species that FAO Fishstat identifies, Bluefin, Southern Bluefin and Bigeye tunas are solely consumed as Sashimi, and therefore mostly exported to Japan. These tuna species are not worth fishing commercial resources unless they are purchased by Japanese. If we view Japanese consumers as a unique buyer, the market structure is characterized as a monopsony. Moreover, if the tuna is frozen, the product will be rocked in the closed distribution channel where the temperature of the cold-chain is not a standard one, minus 20 degree, but rather an extreme cold, minus 60 degree: such storage does not exist anywhere else. Despite such monopsonistic structure, the export prices of these species are not low compared with other marine products. We will further examine market structure and degree of concentration of world sashimi market. Other two species, Yellowfin and Albacore, are consumed both as canned product and Sashimi. Export price of Sashimi tuna is more than twice as high as that for canned material. Nevertheless, the supply of tuna to canning sector has not been ended off nor had the resource been depleted yet as a result of competitive catch. It is expected that the difference of fishing/ distribution costs, demanded size, and the risk-return composition influenced the behavior of world tuna fishers and allowed some diversity in fishing methods and distribution. In fact, some fishing enterprises in Taiwan and the Philippines supply to both Sashimi and canning markets. While in Japan, there is no such example. We will examine the rational and sustainability of such co-existence of different distribution channels that share the same tuna resource

Social Costs of Keeping Pension Fishers in the Community: The Case of Japan

In this paper, we estimated the costs and benefits of keeping pension fishers in the community. 34% of the 200 thousand fishers in Japan are over the age of 65. Since the fishers over 65 are pensioners, their fishery income is an additional source of livelihood. The average yearly income of coastal fishers is US$30,000, and the maximum amount of pension that fishers can receive is US$10,000. The benefits of continuing to fish for pension fishers are their fishery income, certain food supply for themselves, associated benefits of maintaining membership with fishery cooperatives, and their participation with the community. There is no loss, for their opportunity costs are zero, and they are not forced to work. The benefits to the community, on the other hand, can be identified as opportunity costs that might amount if they retire, such as the costs of day-care services provided for free for the elderly and some social security payments provided for the poor. The fishery sector pays additional costs, such as the maintenance costs of fishery infrastructures, hidden costs bared by stagnant fishery reform, and annoying paternalism. The fishing community could have adopted more efficient fishing gears if their total population in the community was 36% less than otherwise, that in turn could have brought additional income or time to remaining young fishers. We compared these costs and benefits and concluded that we will be better off by letting pension fishers fish since the benefits, US$1.909billion, overwhelm the costs, US$566million

Problems of Export-Oriented Yellowfin Tuna Industry -Indonesia and the Philippines

In this paper, we examine the problems inherent in the export-oriented tuna industry taking the Philippines and Indonesia as examples. Although problems are reduced to the depletion of or possible depletion of tuna resources, we intend to clarify the industry structure that may have led to such local depletion. Though Yellowfin tuna is the main species for investigation, we also refer to tuna as a whole and to skipjack specifically. In Chapter 1, we survey the overall tuna market. The characteristics are the concentration of production and consumption sites. In Chapter 2, we discuss the tuna industry in the Philippines. Small tuna and skipjack are caught by purse-seines with the combination of FADs. Tuna canning industry is also developed. In Chapter 3, we discuss the tuna industry in Indonesia, which is well endowed with tuna and skipjack resources. Since the canning industry is not fully developed, Indonesia takes the role of supplying the raw material to other countries. In Chapter 4, we point out that the structure of the industry does not inherently build in sustainable resource use mechanism. We consider who is responsible for the local depletion of resource, whether it is the producer, government, or the consumer

The Value Chain for Philippine Tuna Commodity: Recent Developments and Future Directions

This paper attempts to determine and analyze the factors affecting the value chain of tuna commodity in the Philippines. It also identifies the key players in the industry, and their roles and contributions in the value chain. The paper will utilize both primary and secondary data in the analysis. Secondary sources of data are mainly from the government institutions and private companies. Primary data consists of information obtained from personal interviews and observations covering the period 1999 and 2007. Four tuna canneries, out of six canneries, operating in the Philippines including other companies engaged in tuna and tuna-related businesses were interviewed. The products involved in the study comprised of fresh, frozen tuna and processed tuna products aimed at the export and domestic markets. Most of these products used primarily Yellowfin and Skipjack, which were caught in the Philippines and in the neighboring Southwest Pacific waters. An integrated framework that describes the commodity flow, process, and requirements in every phase of the value chain will be presented. Recent developments and future directions shall also be discussed given the economic, institutional, and environmental concerns faced by the tuna stakeholders. Cost efficiency, steady supply and global competitiveness are the major issues, among others, that need to be addressed to ensure the sustainability of the industry

Risk assessment for hepatitis E virus infection from domestic pigs introduced into an experimental animal facility in a medical school

Hepatitis E virus (HEV) is known to cause zoonotic infections from pigs, wild boars and deer. Domestic pigs have been used as an experimental animal model in medical research and training; however, the risks of HEV infection from pigs during animal experiments are largely unknown. Here, we retrospectively investigated the seroprevalence and detection rates of viral RNA in 73 domestic pigs (average 34.5 kg) introduced into an animal experimental facility in a medical school during 2012-2016. We detected anti-HEV immunoglobulin G antibodies in 24 of 73 plasma samples (32.9%), though none of the samples were positive for viral RNA. Plasma samples of 18 pigs were sequentially monitored and were classified into four patterns: sustained positive (5 pigs), sustained negative (5 pigs), conversion to positive (6 pigs) and conversion to negative (2 pigs). HEV genomes were detected in 2 of 4 liver samples from pigs that were transported from the same farm during 2016-2017. Two viral sequences of the overlapping open reading frame (ORF) 2/3 region (97 bp) were identical and phylogenetically fell into genotype 3. A 459-bp length of the ORF2 region of an amplified fragment from a pig transported in 2017 was clustered with the wbJYG1 isolate (subgenotype 3b) with 91.5% (420/459 bp) nucleotide identity. Based on our results, we suggest that domestic pigs introduced into animal facilities carry a potential risk of HEV infection to researchers, trainees and facility staff. Continuous surveillance and precautions are important to prevent HEV infection in animal facilities

Introduction for Fisheries and Aquatic Biology

Chapter I. Aquatic Environment. Ken FURUYA and Ichiro YASUDA : chapter_1.pdfChapter II. Biology and Ecology of Aqua-Shere. Toyoji KANEKO, Katsumi TSUKAMOTO, Atsushi TSUDA, Yuzuru SUZUKI and Katsufumi SATOH : chapter_2.pdfChapter III. Aquatic Resource and Production. Ichiro AOKI, Kazuo OGAWA, Taku YAMAKAWA and Tomoyoshi YOSHINAGA : chapter_3.pdfChapter IV. Chemistry of Aquatic Organism and Their Utilization. Hiroki ABE, Shugo WATABE, Yoshihiro OCHIAI, Shigeru OKADA, Naoko YOSHIKAWA, Yoshiharu KINOSHITA, Gen KANEKO and Shigeki MATSUNAGA : chapter_4.pdfChapter V. Relation between Aqua-Shere and Human Life. Hisashi KUROKURA, Hirohide MATSUSHIMA, Shingo KUROHAGI, Haruko YAMASHITA, Akinori HINO, Kazumasa IKUTA, Satoquo SEINO, Masahiko ARIJI, Ken FURUYA, Junichiro OKAMOTO and Nobuyuki YAGI : chapter_5.pdfPart of "Introduction for Fisheries and Aquatic Biology