Deep water mass characteristics and interannual variability in the North and Central Aegean Sea

The characteristics and interannual variability of the deep water masses in the North and Central Aegean Sea are being investigated through the data sets of the Hellenic Navy Hydrographic Service (HNHS) and the MEDATLAS 1997 project. In the period between 1987 and 1993, the densest deep water in the Mediterranean has been produced in the Aegean Sea (with σ_θ densities reaching up to 29.6 kg/m³), contributing to what has been called the Eastern Mediterranean Transient. The examination of time series of mean integrated values of θ, S and σ_θ below the depth of 500 dbar reveals the significant deep water density increase after 1987 in all of the deep basins in the area. Data suggest that the density increase of 1987–1988 is mainly attributed to a temperature drop, while in 1993, an even more intense density increase is observed, characterized this time by an abrupt salinity increase. We assume that the increased salinity necessary to produce deep water masses with the observed characteristics was not locally produced but rather advected from the Levantine through the South Aegean. After 1993, no new deep water formation episodes have been observed. A series of Θ–S diagrams derived from HNHS CTD casts covering the period between 1993 and 2000, depict the different characteristics of the deep water masses in the area. As 1993 marks the end of the formation period, observed differences between basins in that year must be attributed to different deep water formation sites. Thereafter, the stagnating deep water in the North and Central Aegean basins has been slowly gaining buoyancy by losing salt and gaining heat. The rate at which this phenomenon takes place varies between different deep basins. It is suggested that these variations are linked to the different volumes of each basin as well as to the general circulation features of the Aegean Sea.     

The significance of the International Tribunal for the Law of the Sea for the shipping industry

The International Tribunal for the Law of the Sea (ITLOS) was established by the 1982 United Nations Convention on the Law of the Sea as a body to settle disputes between States Parties to the Convention regarding the interpretation or application of the Convention s provisions, including provisions concerning the exercise of the powers of States over shipping and the discharge by states of their responsibilities and obligations in relation to ships.ITLOS is competent to deal with disputes in which a State is alleged to have wrongly interfered with or otherwise restrained the operation of a vessel when it is in a port of the State or within the territorial sea or exclusive economic zone of the State.In its previous judgments, ITLOS has provided clarifications of some important areas of the law of the sea concerning the operation and regulation of shipping by flag States and other states.ITLOS plays a key role in the regime of the Law of the Sea Convention relating to the prompt release of ships and their crews that are arrested or detained in a foreign port.ITLOS also has the possibility to serve as ajudicial organ for the settlement of disputes under other maritime agreements and contracts, if the parties to the agreements or contracts agree to confer jurisdiction on it.There are many advantages to be gained by States and shipping operators from using ITLOS as the body for the settlement of disputes under agreements. These advantages include savings in time and expenses.     

Validation of a MATLAB Railway Vehicle Simulation Using a Scale Roller Rig

A 1/5 scale roller rig has been constructed for use in analysing the dynamic behaviour of railway vehicles. The roller rig includes a servo hydraulic system to allow a realistic input of track irregularities at the rollers and instrumentation is fitted to allow measurement of the position and acceleration of the bodies. This paper reports on the first stage in validating the behaviour of the roller rig using a relatively simple, linear computer model constructed in MATLAB. Initial results show good correlation between the behaviour seen on the roller rig and that predicted by the model.     

隧道建筑防火：指南、规定、现实以及适当的措施

本文论述了隧道建筑防火的规定以及一些适当的措施。[编者按]     

Relationships between near-bottom dissolved oxygen and sediment profile camera measures

The United States Environmental Protection Agency (U.S. EPA) and other environmental authorities regulate concentrations of dissolved oxygen (DO) as a measure of nutrient-related eutrophication in estuarine and coastal waters. However, in situ DO concentrations are extremely variable, and their characterization requires an extensive sampling program to provide data over meaningful scales of time and space. In contrast, benthic faunal communities integrate the impacts of low DO over time, and can be rapidly assessed using benthic imaging. The goal of this study was to quantify the relationships between near-bottom dissolved oxygen and measures derived from benthic imaging with a sediment profile camera. We monitored three stations in Narragansett Bay (Rhode Island, USA) for DO and other water quality parameters 15–20 cm above the sediment surface on 15-minute intervals between July and November 2002, and regularly sampled these stations with a sediment profile camera throughout this time period. These soft-sediment stations encompassed several DO environments. We tested for relationships between near-bottom DO and several camera measures, including Nilsson and Rosenberg's Benthic Habitat Quality (BHQ) index, the apparent Redox Potential Discontinuity (aRPD) depth, and various faunal features that can be identified in sediment profile images. Camera measures were examined against a variety of methods of characterizing DO (including mean DO, and the percent of time under various DO thresholds), over a span of time scales from 1 day to 49 days. The best relationship (highest r²) between near-bottom DO and BHQ was found when DO was evaluated as the percent of time under a hypoxic threshold of 2.6 mg l^− 1 over a 28-day time scale (by examining DO records over the 28 days preceding each camera deployment). We found that, over several benthic settings, the BHQ index was successful at identifying environments that had experienced relatively high or low DO over the preceding four weeks. Our sediment profile data showed more variability with DO in the intermediate values of BHQ. We conclude that sediment profile camera measures correlate to DO in areas where low DO is the primary stressor, integrate DO over ecologically relevant time scales, and enable sampling over spatial scales that are meaningful for mapping by virtue of rapid deployment and analysis. We submit that sediment profile camera imagery is a useful assessment and mapping tool for environmental managers interested in benthic condition and in first-order quantitative estimates of near-bottom DO regimes in areas where low DO is the primary benthic stressor.     

Panama Canal And Maritime Industry：An International Perspective

2007年6月13日，巴拿马运河管理局在上海浦东香格里拉大酒店举办“巴拿马海运日”，巴拿马运河管理局国际顾问委员会主席、国际海事组织（IMO）前秘书长威廉·A·奥尼尔先生在开幕仪式上发表了演讲。奥尼尔先生的讲话着重强调海运在当代经济和社会发展中不可替代的巨大作用，集装箱化又是影响最大的因素之一，而且在可持续发展大趋势下，     

克服试验误差

新型高选择性药品的出现推动更大更复杂试验的趋势。日益增长的治疗复杂性激发西欧和北美的研究者寻找方法来实现临床增长的要求。     

Estimation of copepod production in a flooded savanna of Venezuela

This is the first contribution to the copepod production in Venezuelan tropical savannas. Total abundance, biomass, production and mean P/B ratio of nauplii, copepodids and adults were determined in interdaily samples from a flooded, embanked savanna during February and March (end of dry season), and May (beginning of rainy season). Highest values of biomass and total production were recorded during dry season (61.5 mg m⁻³, 153.8 mg m⁻³ day⁻¹, respectively), compared to the rainy season (5.6 mg m⁻³, 45.9 mg m⁻³ day⁻¹). The last values are related to a low population density found during rainy season. Highest production were observed in copepodids at the end of the dry season. Significant differences of production between nauplii and copepodid stages, as well as between nauplii and adults, were also found.     

Changes in multi-mode bus transit efficiency, 1988–1992

This paper examines the claim that US bus transit productivity has declined in recent years. It does so with reference to a piecewise-linear best-practice (DEA) production frontier, computed for multi-modal bus transit between 1988 and 1992. Efficiency is measured both by a Russell (static) and Malmquist (dynamic) measure of productivity change. The principal finding is that, overall, bus transit efficiency has improved slightly over the period.     

电动汽车驱动控制的PWM新技术

文章介绍了电动汽车交流驱动中采用确定脉宽调制(DPWM)技术和随机脉宽调制(RPWM)技术的比较研究结果.RPWM方法替代DPWM方法,采用Avant!公司先进的仿真软件SABER,其重点是降低电磁干扰(EMI).为了评估PWM技术对驱动性能的影响,同时对驱动效率,转矩脉动和电流控制系统动态响应进行了研究.文中考虑了逆变器开关频率随机变化定义的2种RPWM技术:一种技术是调制器的取样频率与开关频率同步变化;另一种技术是取样频率固定且等于平均开关频率.研究表明:在驱动性能几乎不受影响的同时,RPWM技术降低EMI的良好潜力,可使EMI下降10dB或更多.