射频热凝靶点消融术在颈腰椎间盘突出症中的应用

目的观察射频热凝靶点消融术在治疗颈腰椎间盘突出症中的疗效及安全性,并对该新技术的推广应用做出评估。方法对120例经CT或MRI检查确诊的颈腰椎间盘突出症患者,根据临床症状、CT或MRI结果确定射频热凝的靶点位置,在C型臂引导下穿刺到靶点,通过椎间盘造影确定电极已进入靶点,再行阻抗测试、电生理测试及温度测试后,给予86-94℃温度,对靶点进行热凝消融。此时,通常可以复制出原有的腰腿痛症状,用此温度治疗4个周期,每个周期100 s。结果本组120例患者,经过该技术治疗后,其中73例治疗效果达优级,30例治疗效果良好,13例效果较差,4例无效,优良率85.8%。有4例患者术后并发轻微头痛、头晕等不适症状,均于2日内消失。余无其他并发症。结论射频热凝靶点消融术是目前治疗腰椎间盘突出症的最新的、且安全有效的方法。     

The Gulf Stream, rings and North Atlantic eddy structures from remote sensing (Altimeter and SeaWiFS)

Seasonal SeaWiFS chlorophyll a concentrations cycles and annual changes of altimeter Sea Level Anomaly are derived for the subtropical North Atlantic near  35°N and along a Gulf Stream axis. Spatial structure of SeaWiFS, is defined in terms of deviations from a local seasonal cycle and examined in relation to altimeter eddy structure. In the subtropical region near 35°N, SeaWiFS structure is evident during the spring bloom period with a scale of  430 km, or about twice the eddy scale. A Gulf Stream axis has been selected as a region where the Sea Level Anomaly variance is a maximum. Eddy propagation speeds and scales are examined. Cold-core (cyclonic) rings correspond to areas of high SeaWiFS chlorophyll a. Warm-core (anticyclonic) rings relate to areas of low chlorophyll concentration. Both SeaWiFS structure and eddy structure have a spatial scale of  450 km or twice the ring scale along the Gulf Stream axis. SeaWiFS chlorophyll anomalies and Altimeter Sea Level Anomaly structure have an overall negative correlation coefficient of r = − 0.34. Swirl currents between eddies redistribute surface chlorophyll concentrations and can spatially bias maximum and minimum concentration levels off eddy centre.     

Choice valuation of traffic restrictions: Noise, pollution, and congestion preferences. A note

This Note looks at the choice valuation restrictions on traffic entering the city of Lisbon, based on individual preferences in relation to noise, pollution and congestion. The analysis employs a questionnaire distributed in 2007 to ascertain the significant characteristics of traveling to Lisbon, with the aim of curbing the number of cars that are associated with the probability of individuals supporting a charge on motor vehicles entering the city. The model also takes into account the uncontrolled heterogeneity of the data.     

How do people respond to congestion mitigation policies? A multivariate probit model of the individual consideration of three travel-related strategy bundles

This study explores the relationships between adoption and consideration of three travel-related strategy bundles (travel maintaining/increasing, travel reducing, and major location/lifestyle change), linking them to a variety of explanatory variables. The data for this study are the responses to a fourteen-page survey returned by nearly 1,300 commuting workers living in three distinct San Francisco Bay area neighborhoods in May 1998. We first identified patterns of adoption and consideration among the bundles, using pairwise correlation tests. The test results indicate that those who have adopted coping strategies continue to seek for improvements across the spectrum of generalized cost, but perhaps most often repeating the consideration of a previously-adopted bundle. Furthermore, we developed a multivariate probit model for individuals’ simultaneous consideration of the three bundles. It is found that in addition to the previous adoption of the bundles, qualitative and quantitative Mobility-related variables, Travel Attitudes, Personality, Lifestyle, Travel Liking, and Sociodemographics significantly affect individual consideration of the strategy bundles. Overall, the results of this study give policy makers and planners insight into understanding the dynamic nature of individuals’ responses to travel-related strategies, as well as differences between the responses to congestion that are assumed by policy makers and those that are actually adopted by individuals.

Modelling daily activity program generation considering within-day and day-to-day dynamics in activity-travel behaviour

This paper presents a comprehensive econometric modelling framework for daily activity program generation. It is for day-specific activity program generations of a week-long time span. Activity types considered are 15 generic categories of non-skeletal and flexible activities. Under the daily time budget and non-negativity of participation rate constraints, the models predict optimal sets of frequencies of the activities under consideration (given the average duration of each activity type). The daily time budget considers at-home basic needs and night sleep activities together as a composite activity. The concept of composite activity ensures the dynamics and continuity of time allocation and activity/travel behaviour by encapsulating altogether the activity types that are not of our direct interest in travel demand modelling. Workers’ total working hours (skeletal activity and not a part of the non-skeletal activity time budget) are considered as a variable in the models to accommodate the scheduling effects inside the generation model of non-skeletal activities. Incorporation of previous day’s total executed activities as variables introduces day-to-day dynamics into the activity program generation models. The possibility of zero frequency of any specific activity under consideration is ensured by the Kuhn-Tucker optimality conditions used for formulating the model structure. Models use the concept of random utility maximization approach to derive activity program set. Estimations of the empirical models are done using the 2002–2003 CHASE survey data set collected in Toronto.

Identifying peer states for transportation system evaluation &; policy analyses

The majority of comparisons between state transportation systems do not control for characteristics that may vary greatly between states (e.g., vehicle miles traveled). A shortcoming of such analyses is that a state’s individual characteristics can be highly influential in determining how transportation policy is set and funds are spent. The purpose of this paper is to extend previous efforts to create groups of similar peer states by developing a new methodological framework that incorporates demographic, temporal, and locational variability into the peer group delineations. We collected historical data for 42 variables on transportation infrastructure, population, economy, growth, topography and weather. To examine trends before and after the passage of ISTEA we gathered data over two time periods: 1985 through 1990 and 1995 through 2000. Using principal components analysis (PCA) we reduced variables into seven components, and then statistically clustered states into peer groups for each time period based on the components and the remaining variables. We identified a range of cluster solutions and demonstrate how cluster statistics help to describe the contextual basis behind the peer grouping. The results of this study are to provide government agencies, researchers and the public with a systematic methodological framework for identifying peer states that reflect similar attributes contributing to the development and maintenance of state transportation systems.

Curbing automobile use for sustainable transportation: analysis of mode choice on short home-based trips

This paper analyzes transportation mode choice for short home-based trips using a 1999 activity survey from the Puget Sound region of Washington State, U.S.A. Short trips are defined as those within the 95th percentile walking distance in the data, here 1.40 miles (2.25 km). The mean walking distance was 0.4 miles (0.6 km). The mode distribution was automobile (75%), walk (23%), bicycle (1%), and bus (1%). Walk and bicycle are found less likely as the individual’s age increases. People are more likely to drive if they can or are accustomed to. People in multi-person families are less likely to walk or use bus, especially families with children. An environment that attracts people’s interest and provides activity opportunities encourages people to walk on short trips. Influencing people’s choice of transport mode on short trips should be an important part of efforts encouraging the use of non-automobile alternatives.

Ship resistance of quadramaran with various hull position configurations

Multihull ships are widely used for sea transportation, and those with four hulls are known as quadramarans. Hull position configurations of a quadramaran include the diamond, tetra, and slice. In general, multihull vessels traveling at high speeds have better hydrodynamic efficiency than monohull ships. This study aims to identify possible effects of various quadramaran hull position configurations on ship resistance for hull dimensions of 2 m length, 0.21 m breadth, and 0.045 m thickness. We conducted a towing test in which we varied the hull spacing and speed at Fr values between 0.08 and 0.62 and measured the total resistance using a load cell transducer. The experimental results reveal that the lowest total resistance was achieved with a diamond quadramaran configuration at Fr = 0.1-0.6 and an effective interference factor of up to 0.35 with S/L = 3/10 and R/L = 1/2 at Fr = 0.62.     

Effects of a classroom-based bridge resource management training on knowledge,attitudes, behaviour and performance of junior naval officers

This study asses the effectiveness of classroom-based bridge resource management (BRM) training for junior naval officers, in which general principles of human behaviour and performance in teams and under stress were conveyed. Although BRM training is recommended by the International Maritime Organization and is increasingly common in seafaring, very little is known about whether the adaptation of crew resource management (CRM) training from aviation to the maritime domain has been successful and what type of training is effective. A study with a quasi-experimental, two-factorial mixed design was conducted with BRM training as the between factor and time as the within factor. For 117 study participants, evaluation criteria were assessed on all levels as defined by Kirkpatrick (Train Dev J, 178–192 1979): subjective training evaluation, knowledge, attitudes and behaviour as well as performance while commanding a vessel during a real-world exercise. BRM participants showed better subjective training evaluations and more BRM-related knowledge than controls. Training did not produce differences between groups regarding BRM-related attitudes, the demonstration of non-technical skills or the overall success in the real-world exercise. Overall, BRM training effectiveness was rather low, which can most probably be attributed to the focus of training on generalizable knowledge, skills and attitudes at the expense of their specific application to the context of the real-world exercise. In the design of BRM and CRM training courses alike, the effective application of general principles to a given context must be defined, and the application must be emphasised during training delivery.