经济危机下日本的劳动和社会保障

2008年,金融危机使世界经济迅速陷入了大萧条。起初被专家认为受影响较小的日本经济也遭受了重大打击。日本的劳动和社会保障在经济危机的冲击下面临诸多问题。20世纪90年代以后日本就业结构在经济急速恶化的背景下发生了很大变化。经济社会的诸多问题对不同社会集团的影响不同。一般而言,当经济增长时,大多数社会集团都会从中受益;而当经济面临危机时,不同社会集团之间会出现差别,问题集中出现在特定的社会集团中。     

Family Changes in the Context of Lowest-Low Fertility: The Case of Japan

Abstract: Japan has currently one of the lowest-low fertility rates in the world. Low fertility in Japan is due to the extreme postponement of marriage and childbearing, and their weak recuperation in women in their 30s, as well as very low levels of cohabitation and extra-marital fertility. Both changing and unchanged aspects of families are related to lowest-low fertility in Japan. Although premarital sexual activities have increased, women's contraceptive initiative is very weak: they may be connected with weak partnership formation. "Parasite singles", "freeters", or "NEETs", probably related to weak family formation, have increased, but they may be connected with strong filial bondage derived from the traditional family system, i.e. Women have been normatively, educationally, and occupationally emancipated, but gender norms are currently divided in half among Japanese people, which may deter the revising of working conditions for women with children, leading to delaying family formation among working women. Lowest-low fertility conversely brings about family changes. Its direct effect is the increase of lifetime celibacy and childless couples, which may jeopardize the universality of families. Its indirect effect is through policy response to low fertility as well as labor shortages and population aging: recently, both family and labor policies have been strengthened to make it easier for working women to continue their jobs after marriage and childbirth, which might in turn promote family formation in Japan.     

Temporary Contracts,Employment Protection,and Collective Bargaining

This paper examines the effect of employment protection in a matching model with endogenous job destruction, collective bargaining, and two types of employment contracts. Using this framework, we show that (i) the impact on job creation and job destruction caused by reducing the firing costs associated with temporary jobs depends on the labour unions' bargaining strength and the gap in firing costs between contracts; (ii) reducing the firing costs associated with permanent jobs unambiguously decreases equilibrium unemployment if labour unions have strong bargaining power; and (iii) the impact caused by the firing costs differs between collective and individual bargaining.     

Geometric consistency of principal component scores for high-dimensional mixture models and its application

In this article, we consider clustering based on principal component analysis (PCA) for high-dimensional mixture models. We present theoretical reasons why PCA is effective for clustering high-dimensional data. First, we derive a geometric representation of high-dimension, low-sample-size (HDLSS) data taken from a two-class mixture model. With the help of the geometric representation, we give geometric consistency properties of sample principal component scores in the HDLSS context. We develop ideas of the geometric representation and provide geometric consistency properties for multiclass mixture models. We show that PCA can cluster HDLSS data under certain conditions in a surprisingly explicit way. Finally, we demonstrate the performance of the clustering using gene expression datasets.     

Effects of parasitoid community structure upon the population dynamics of the honeysuckle leafminer,Chromatomyia suikazurae (Diptera: Agromyzidae)

Population dynamics of a leafminer,Chromatomyia suikazurae (Agromyzidae, Diptera) and its parasitoid community were studied for ten years at seven natural populations along an altitudinal gradient in Japan. This species which mines leaves of a forest shrub,Lonicera gracilipes (Caprifoliaceae), was attacked by 25 hymenopterous parasitoid species. Annually, the parasitoid community structure varied less within a population than among populations. The seven parasitoid communities were clustered into three groups corresponding to the altitudinal gradient: (a) lowland communities dominated by late-attacking, generalist pupal idiobiont eulophids and with highest species diversity, (b) hillside communities dominated by an early-attacking, specialist larval-pupal koinobiont braconid and (c) highland communities dominated by an early-attacking, generalist larval idiobiont eulophid. Annual changes of the host larval densities among the local populations were largely synchronous rather than cyclic. Among these populations, host density levels and mortality patterns greatly varied. By analyzing these inter-populational differences of host mortality patterns, the following conclusions were drawn: (1) The host mortality patterns were determined by the host utilization patterns of the locally dominant species. (2) The host pupal mortality but not larval mortality was related to species diversity but not to species richness itself of each parasitoid community. (3) Density dependence was detected only in pupal mortality at a lowland population dominated by late-attacking pupal parasitoids. These results suggest that interspecific interactions of parasitoids add additive effects to host population dynamics dissimilarly among local populations with different parasitoid communities.     

Seasonality and vertical structure of light-attracted insect communities in a dipterocarp forest in Sarawak

Nocturnal flying insects were collected monthly for 13 months using ultra violet light-traps set at various vertical levels in a weakly-seasonal, tropical lowland dipterocarp forest in Sarawak, Malaysia. Abundance, faunal composition, size distribution and guild structure of these samples were analyzed with respect to temperal and vertical distributions. The nocturnal flying insect community in the canopy level was highly dominated by fig wasps (84%) in individual number, and by scarabaeid beetles (28%) in weight. A principal component analysis on monthly catches detected non-random, seasonal trends of insect abundance. The first two principal trends were an alternation of wetter (September to January) and less wet seasons (February to August) and an alternation between the least wet (January to March) and the other seasons. Many insect groups were less abundant in the least wet season than the other seasons, whilst inverse patterns were found in Scarabaeidae and Tenebrionidae. Significantly positive and negative correlations between monthly catch and rainfall were detected only in ovule-feeders and in phloem-feeders, respectively. Delayed, significant negative correlations between monthly catch and 1–3 month preceding rainfall were more frequently detected in phytophages, phloem-feeders, seed-feeders, wood-borers and scavengers. The peak in abundance along vertical levels were found at the canopy level (35 m) for phloem-, ovule-, seed-, root-, fungal-feeders and nectar collectors, at an upper subcanopy level (25 m) for scavengers and aquatic predators, and at a middle subcanopy level (17 m) for ants. Catches at the emergent level (45 m) did not exceed those at the canopy level.     

GPS cell phone tracking in the Greater Tokyo Area: A field test on raccoon dogs

We tested instantaneous GPS cell phone telemetry to record movement data of raccoon dogs (Nyctereutes procyonoides) in Abiko city, Greater Tokyo, Japan. We monitored the changes in locations of six raccoon dogs in various land use types such as roads, golf courses, towns, rice and crop paddies, and forest. Data were downloaded instantaneously using cell phone networks and the internet, remotely to a desktop computer. We obtained 410 location points and the maximum duration of individual tracking was 144 hours. The success rate of GPS positioning varied among individuals. On average, the success rate of three raccoon dogs in a relatively open area was 98% and that of three raccoon dogs in a mosaic area was 70%. In total, 372 of the data points (91 % of all downloaded data) with reliable accuracy were used to analyze movement speed during the day time as well as habitat use of the raccoon dogs, revealing various spatial and temporal behavioral patterns. Human activities were the likely cause of characteristic behaviors in tall weed patches and golf courses, and daily patterns of movement. Our results indicate the potential utility of GPS cell phone tracking to efficiently monitor and manage wildlife in changing urban environments.     

Risk Assessment of the Carbon Nanotube Group

This study assessed the health risks via inhalation and derived the occupational exposure limit (OEL) for the carbon nanotube (CNT) group rather than individual CNT material. We devised two methods: the integration of the intratracheal instillation (IT) data with the inhalation (IH) data, and the “biaxial approach.” A four‐week IH test and IT test were performed in rats exposed to representative materials to obtain the no observed adverse effect level, based on which the OEL was derived. We used the biaxial approach to conduct a relative toxicity assessment of six types of CNTs. An OEL of 0.03 mg/m³ was selected as the criterion for the CNT group. We proposed that the OEL be limited to 15 years. We adopted adaptive management, in which the values are reviewed whenever new data are obtained. The toxicity level was found to be correlated with the Brunauer‐Emmett‐Teller (BET)‐specific surface area (BET‐SSA) of CNT, suggesting the BET‐SSA to have potential for use in toxicity estimation. We used the published exposure data and measurement results of dustiness tests to compute the risk in relation to particle size at the workplace and showed that controlling micron‐sized respirable particles was of utmost importance. Our genotoxicity studies indicated that CNT did not directly interact with genetic materials. They supported the concept that, even if CNT is genotoxic, it is secondary genotoxicity mediated via a pathway of genotoxic damage resulting from oxidative DNA attack by free radicals generated during CNT‐elicited inflammation. Secondary genotoxicity appears to involve a threshold.     

Associating Gene Therapy with the Human Genome Project

As is often the case with cutting-edge biomedical technology, the introduction of gene therapy in Japan provoked discussions of ethics and safety while offering little hope for dramatic recovery. Nevertheless, only 5 years after the first authorized clinical trial in the USA, the first Japanese trial was conducted in 1995. This trial event garnered extensive media coverage but yielded little opposition. To understand the public reaction, a range of sources were examined, including news media and popular scientific magazines. In the case of Japan, public acceptance did not mean enlightened consent; rather, it meant that interactions among researchers, the media, and the populace brought about a new interpretation of the technology.     

Preoperative sexual status of Japanese localized prostate cancer patients: comparison of sexual activity and EPIC scores

Objective: This study aimed to evaluate the relationship between sexual activity and sexual function using questionnaires distributed to middle-aged Japanese patients with localized prostate cancer.

Methods: A total of 145 patients who underwent radical prostatectomy were enrolled in the survey reported on herein. Sexual activity and sexual function were investigated via the Expanded Prostate Cancer Index Composite (EPIC) and an original self-reported questionnaire.

Results: Of participants, 24.1% and 20.7% had sexual activity within a month period as investigated via the EPIC and original questionnaire, respectively. However, 29.7% of all those who reported sexual activity rate reported “about once every 2?months to a year,” as shown in the original questionnaire. Regarding sexual function as addressed through EPIC, no results within that questionnaire’s measure of sexual function showed significant differences among patients with a rate of actual sexual activity.

Conclusions: The present survey showed that more than quarter of preoperative middle-aged Japanese prostate cancer patients surveyed had actual sexual activity, though not within the preceding 4?weeks. To precisely evaluate sexual function of middle-aged Japanese patients, it is necessary to consider actual sexual activity.