关于陕西发展观光农业的研究

观光农业以其较好的经济效益和社会效益,成为我国各地竞相发展的朝阳产业。本文结合陕西实际和观光农业发展的一般规律,并借鉴国内外的发展经验,提出了陕西发展观光农业应遵循的基本原则:统一规划,合理布局;突出特色和文化内涵;因地制宜;可持续发展;循序渐进。     

永乐款漆器

明代是中国古代漆工艺发展史上的高峰期,而永乐漆器又是明代漆器中的佼佼者,工艺水平达到了较高的成就。本文对永乐款漆器产生的条件、取得的成就、款识、漆包、品种、图案特点等进行了分析和较全面的评述。     

Lifestyle,occupation, and whole bone morphology of the pre‐Hispanic Maya coastal population from Xcambó, Yucatan,Mexico

The present bioarchaeological study examines the external diaphyseal geometric properties of humeri, radii, femora and tibiae of the Classic period skeletal population of Xcambó, Yucatan, Mexico. The diaphysial proportions are evaluated using a biomechanical approach together with data from the material context and other osteological information. Our intent is to provide new answers to questions concerning lifestyle, domestic labour division and subsistence strategies of this coastal Maya settlement that was inhabited from the Late and Terminal Preclassic (300 BC–350 AD) to the Postclassic Period (900–1500 AD). Our results provide evidence for a marked sexual division of labour when compared with values from contemporaneous inland populations. The overall male and female loading patterns differ remarkably in terms of form and in bilateral comparison. A high directional asymmetry in the upper limbs is evident among males, a condition related to maritime transportation and trading activities. On the other hand, female upper limbs are characterized by very low side differences. Forces on the arms of women were probably dominated by food processing, in particular the grinding of grains or seeds. In the lower limbs, males show significantly higher anteroposterior bending strengths, which can be explained by greater engagement in transportation tasks and carrying heavy loads. In the course of the Classic period (350–900 AD), diachronic changes affect the male sample only, which suggests a shift of occupational pattern and physical demands. This shift, in turn, reflects Xcambó's changing role as the centre of a densifying settlement area and its place in the trading activities of northern Yucatan. Other topics of discussion relate to general regional trends and local prehispanic subsistence strategies. Our conclusions emphasize the value of geometric long bone analysis in the reconstruction of activity patterns and lifestyles in ancient coastal settlements. Copyright © 2007 John Wiley & Sons, Ltd.     

What constitutes a ‘trip’? Examining child journey attributes using GPS and self-report

Active travel is associated with improved health and development outcomes in children. Accurate detection of children's travel behaviors and routes, however, is problematic. Travel diaries are often used to collect information on children's travel behaviors, yet no evidence for the accuracy of this methodology exists. This study investigated the validity of children's self-reported trips (origin, destination) compared with an objective criterion (global positioning systems units; GPS). Children (n = 10, 9–11 y) wore the GPS units for seven consecutive days between March and June 2011 and completed travel diaries daily with researcher assistance. Affinity group interviews were conducted in December 2011 with 30 children from two schools to garner perspectives on trip definition, neighborhood perceptions, and to illuminate GPS and travel diary findings. GPS journeys were manually compared with travel diary journeys for destination sequencing, start times, and travel mode. Accuracy in trip sequencing was compared by day type, and journey type using percentage differences and the chi-square (χ²) statistic. Of the 380 trips captured, 54.5% of journey sequences were fully or partially matched, 22.4% were GPS only trips and 23.2% travel diary only. Greater accuracy (full/partial match) was observed for weekdays than for weekend days and for the journey to or from school than for other journeys. Travel mode agreement existed for 99% of matched trips. Although children's travel diaries may confer contextual journey information, they may not provide completely accurate information on journey sequencing. Thematic analysis of affinity group data revealed that reasons for this are multifaceted, including differing concepts of what constitutes a ‘trip’. A combined approach of GPS and travel diary is recommended to gather a comprehensive understanding of children's journey characteristics.     

Diffuse hydrothermal methane output and evidence of methanotrophic activity within the soils at Sousaki (Greece)

Methane soil flux measurements have been made in 38 sites at the geothermal system of Sousaki (Greece) with the closed chamber method. Fluxes range from ?47.6 to 29 150 mg m^?2 day^?1, and the diffuse CH₄ output of the system has been estimated at 19 t a^?1. Contemporaneous CO₂ flux measurements showed a moderate positive correlation between CO₂ and CH₄ fluxes. Comparison of the CO₂/CH₄ soil flux ratios with the CO₂/CH₄ ratio of the gases of the main gas manifestations provided evidence for methanotrophic activity within the soil. Laboratory CH₄ consumption experiments confirmed the presence of methanotrophic microorganisms in soil samples collected at Sousaki. Consumption was generally in the range from ?4.9 to ?38.9 pmolCH₄ h^?1 g^?1 but could sometimes reach extremely high values (?33 000 pmolCH₄ h^?1 g^?1). These results are consistent with recent studies on other geothermal systems that revealed the existence of thermoacidophilic bacteria exerting methanotrophic activity in hot, acid soils, thereby reducing methane emissions to the atmosphere.     

东周楚式戈斑纹的成分与相组成

为探讨东周楚式戈斑纹的处理技术,采用金相显微镜、SEM、EDS、EBSD研究了上海博物馆藏的楚式斑纹戈的成分、显微组织和相组成,讨论了其制作工艺.结果表明:东周楚式戈富锡层厚度不均,以十余μm左右的厚度居多,最多处由4种不同物相组成,分别为η相、ε相、σ相及(α+δ)共析相.富锡层与基体之广日j没有明显的分界线.与现有其它富锡工艺研究成果进行比较,认为此件楚式戈与其它地域的富锡技术具有共同的工艺特征,应为热镀锡工艺.但在工艺参数掌控方面应呈现地域上的差异.     

英语“任务型”教学活动特点之我见

如何在英语课堂教学中体现新的教学理念,如何选择相关的教学内容并设计“任务型”的教学活动,以及在教学活动的具体操作过程中应注意哪些问题,都是英语课堂教学改革的新课题。本文结合作者在教改中一些做法,谈谈对英语“任务型”教学活动特点的几点认识。     

晚明复社的社会活动与社会思想——兼论复社学术的经世取向

晚明文人结社,尤以复社规模最巨,影响最大,活动最频繁.复社的社会活动具有明显的时代特色和政治取向.与复社社会活动形成鲜明照映的是复社的社会思想和经世学术.社会思想在诸如经世济民、名节道义方面,都体现出强烈的社会历史意义;而学术体系中的经学、史学成绩皆有着深刻的经世内涵.复社的社会思想与学术取向,在明清之际的社会转变中,具有不可或缺的、承前启后的重大历史意义.     

Mineral precipitation associated with vertical fault zones: the interaction of solute advection,diffusion and chemical kinetics

This article is concerned with chemical reactions that occur between two interacting parallel fluid flows using mixing in vertical faults as an example. Mineral precipitation associated with fluid flow in permeable fault zones results in mineralization and chemical reaction (alteration) patterns, which in turn are strongly dependent on interactions between solute advection (controlled by fluid flow rates), solute diffusion/dispersion and chemical kinetics. These interactions can be understood by simultaneously considering two dimensionless numbers, the Damköhler number and the Z‐number. The Damköhler number expresses the interaction between solute advection (flow rate) and chemical kinetics, while the Z‐number expresses the interaction between solute diffusion/dispersion and chemical kinetics. Based on the Damköhler and Z‐numbers, two chemical equilibrium length‐scales are defined, dominated by either solute advection or by solute diffusion/dispersion. For a permeable vertical fault zone and for a given solute diffusion/dispersion coefficient, there exist three possible types of chemical reaction patterns, depending on both the flow rate and the chemical reaction rate. These three types are: (i) those dominated by solute diffusion and dispersion resulting in precipitation at the lower tip of a vertical fault and as a thin sliver within the fault, (ii) those dominated by solute advection resulting in precipitation at or above the upper tip of the fault, and (iii) those in which advection and diffusion/dispersion play similar roles resulting in wide mineralization within the fault. Theoretical analysis indicates that there exists both an optimal flow rate and an optimal chemical reaction rate, such that chemical equilibrium following focusing and mixing of two fluids may be attained within the fault zone (i.e. type 3). However, for rapid and parallel flows, such as those resulting from a lithostatic pressure gradient, it is difficult for a chemical reaction to reach equilibrium within the fault zone, if the two fluids are not well mixed before entering the fault zone. Numerical examples are given to illustrate the three possible types of chemical reaction patterns.     

Subsistence change,landscape use,and changing site elevation at the Pleistocene–Holocene transition in the Dordogne of southwestern France

The dramatic topography of the Dordogne Valley region of southwestern France has long been recognized as an influence on prehistoric human settlement and subsistence patterns. Previous research on late Pleistocene settlement patterns in this region implies that, as cold-adapted higher-ranked resources became scarce in the lowlands, site location in the Dordogne and adjacent river valleys should shift towards higher-elevation areas during the period from 18,000 to 6500 years BP. This study employs a GIS-based analysis to evaluate the changing settlement patterns in the Dordogne region at this time. While no significant changes in elevation were found during this period, site elevation variance does appear to increase significantly between the Magdalenian and the Sauveterrian. Explanations for this finding are explored using zooarchaeological data from Moulin du Roc, one of the sites in the data set. Results suggest that the Magdalenian period in the Dordogne may not have been as resource-rich as is often assumed.