Elastic labor supply and agglomeration

This study analyzes the interplay between the agglomeration of economic activities and interregional differences in working hours, which are typically longer in large cities, as they are normally more developed than small cities. For this purpose, we develop a two‐region model with endogenous labor supply. Although we assume a symmetric distribution of immobile workers, the symmetric equilibrium breaks in the sense that firms may agglomerate when trade costs are intermediate and labor supply is elastic. We also show that the price index is always lower, while labor supply, per capita income, real wages, and welfare are always higher in the more agglomerated region.     

秦俑博物馆陶器库房空气污染的物理化特征及其对彩绘陶器的影响

2007年冬季在秦始皇兵马俑博物馆陶器库开展了室内大气污染系列采样工作,持续31天,使用Minivol便携式气溶胶采样仪采集了大气颗粒物样品（PM2．5）,利用AreaRAE—IAQ（PGM5220）测定了库内的微气候特征。结果表明,冬季兵马俑陶器库中的PM2．5的平均质量浓度为76．1μg／m3,明显低于室外,PM25中水溶性离子主要由SO4^3-、NO^3-和NH4^＋组成,与室外相同,表明库内污染物主要受室外控制,而且库内颗粒物偏酸性,库内温差较大,由于颗粒物偏酸性可能会对库内的陶器彩绘颜料中的碳酸钙、碳酸钡及硅酸铜钡等成分产生不利影响,颗粒物的悬浮与沉降也可能会对彩绘产生污损,此外库内剧烈的温度变化也可能会对彩绘陶器的保存带来不利影响。     

Investigation of the temporal change of the sources of Aeolian dust delivered to East Asia using electron spin resonance signals in quartz

The temporal change in the number of oxygen vacancies in quartz was investigated by ob-serving the E1’ center in the atmospheric depositions collected at two cities in Japan in the recent past. The depositions collected at Fukuoka in March show the ESR intensities being correlated with the sum of the number of the days, in the month, on which Kosa was observed while no such correlation was found in the deposition those collected at Akita but a trend of decrease with time. The present results suggest that the number of oxygen vacancies in quartz might be useful to estimate quantitatively the contribution of the dust originated from China to the atmospheric deposition in Japan.     

Trafficking in US Agriculture

Based on a qualitative methodology that includes in‐depth interviews with 90 Mexican migrant smugglers and 45 Central American farmworkers, this article analyzes the three separate elements of trafficking in US agriculture, namely acts, means, and purposes. We conclude that some US employers participate in human trafficking by financing or helping to recruit and transport Mexican and Central American migrants to the US by means of “abuse of a position of vulnerability” for the purposes of involuntary servitude, debt bondage, and sex exploitation.     

日本列岛封土石室墓的展开与连云港石室墓

4世纪后半叶,封土石室墓开始在日本列岛出现。日本列岛的横穴石室受到了朝鲜半岛的影响。九州地区的古坟是最早导入的。5世纪后半叶,与此不同的新型石室在近畿地方出现,并在此后的日本列岛得到了广泛普及。7世纪,由于薄葬化的推进,小型的横口式石椁墓出现,这代表着古坟文化走向了尾声。江苏连云港的封土石室墓的构造,虽与朝鲜半岛和日本列岛两地皆有类似之处,但其与中国的砖结构墓葬和朝鲜古坟的关系也是必须要考虑的。而与日本列岛石室墓的类似,笔者认为是以朝鲜半岛为中介的间接的关联。     

Scales of regional income disparities in the USA, 1955 2003

This article examines multiple dimensions of regional per capitaincome disparities in the USA between 1955 and 2003 with a particularfocus on scalar effects. It combines various exploratory analyticaltools of spatial disparities, including inequality indices,mobility indices, kernel density estimation, spatial autocorrelationstatistics and scale variances, to analyse regional averageper capita income distributions at multiple spatial scales,ranging from counties to multi-state regions. The analysis revealspreviously unrecognised systematic patterns of cross-scalardynamics, whereby spatial income disparities are increasinglymore pronounced at smaller scales in the last few decades.     

Discovery of Iron Grapnel Anchors in Early Modern Ryukyu and Management of Underwater Cultural Heritage in Okinawa,Japan

The Yarabuoki underwater site contains seven iron grapnel anchors and Early Modern Okinawan ceramic jars and is dated to the 16th–19th centuries. The site lies at a depth of 12–32 m off the western coast of Ishigaki Island in Okinawa, Japan. Based on underwater archaeological and broadband multibeam surveys, as well as historical research of the artefacts and Early Modern Ryukyuan shipping, we discuss the possible anchor and vessel types in Ryukyu and Eastern Asia in Early Modern times. We also discuss the efficacy of low‐cost ROV for assisting surveys in shallow‐water environments and the value of educational programmes for promoting the management and conservation of underwater cultural heritage.     

Development of Damage Patterns and Fragility Curves in Brick-nogging Buildings from the Thabeikkyin Earthquake,Myanmar, 2012

The Thabeikkyin earthquake (moment magnitude scale of 6.8) occurred on November 11, 2012; its epicenter was located 25 km from Thabeikkyin Township, Mandalay Region, Myanmar. Many buildings were damaged severely during the earthquake. In this study, damage patterns of brick-nogging buildings were firstly developed, and damage grades were characterized to allow for easy classification of the damaged buildings. The damaged data of all building types in the surveyed areas were collected by classifying the four damage levels as no damage, slight damage, moderate damage, and heavy damage. To develop the damage patterns of brick-nogging buildings, damage categories were arranged into three damage grades (slight, moderate, and heavy damage). Secondly, a questionnaire survey was conducted to calculate the seismic intensities of the affected areas. Medvedev–Sponheuer–Karnik (MSK) seismic intensities for the surveyed areas were estimated by analyzing the questionnaire survey responses. Finally, fragility curves for brick-nogging buildings were constructed using the estimated seismic intensities from the survey responses combined with the damage levels. These fragility curves may be useful to assess damage to brick-nogging buildings and to predict the number of damaged buildings in future earthquakes.     

Thermoluminescence age of quartz xenocrysts in basaltic lava from Oninomi monogenetic volcano, northern Kyushu, Japan

We determined the eruption age of basaltic rocks by application of thermoluminescence (TL) method, which is often used for TL dating, to quartz. Mafic magma only rarely includes quartz because of their mutual disequilibration. The basaltic lavas reported herein include quartz as xenocrysts, as corroborated by their rounded or anhedral shape. The basaltic lava used for this study is from the Oninomi monogenetic volcano in northern Kyushu, Japan. The volcano eruption was estimated as occurring 7.3–29 ka because the lava exists between two widespread tephras: Aira-Tanzawa ash (26–29 ka) and Kikai-Akahoya ash (7.3 ka). We succeed-ed in collecting ca. 200 mg of quartz by decomposition of 30 kg of the lava samples. TL measurements for the lava indicate the eruption age as 15.8 ± 2.5 ka, which is fairly consistent with the stratigraphical estimation. Although the TL method has played a considerable part in constraining the timescale of Quaternary events, its application has been limited to silicic samples. The present result demonstrates the availability of quartz for dating even of mafic rock.