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This paper proposes a new form of passive UHF RFID system which has high tag detection accuracy but lower costs than existing systems for wide-range RFID scenarios requiring greater flexibility. This new system concept consists of a central baseband controller and a remote antenna subsystem, connected using a twisted-pair cable. Baseband signals are transmitted over the twisted-pair cable during the inventory session, and the transmitted radio frequency (RF) signals are up and down converted in the antenna subsystem. – 88 dBm reader sensitivity is achieved with an active leakage cancellation block, showing little degradation in tag detection performance over a 300m of Cat5e cable between the controller and the antenna. An average leakage suppression of 36.9 dB can be achieved with a fixed transmission power of 26.5 dBm. Compared with conventional RFID systems using coaxial cables between the reader and antenna, the presented system is superior in terms of link distance, link cost, and installation flexibility.

Monitoring the training of amateur long-distance cross-country skiers (XCS) can help athletes’ achieve a higher exercise capacity and protect their health. The aim of this study was to assess body composition changes and lipid profiles in middle-aged amateur long-distance XCS after four months of training, including specialized roller ski training. The results of the time-to-exhaustion (TTE) test and blood tests and changes in body composition were analyzed with basic descriptive statistics: the paired Wilcoxon test was used to compare the results (initial and final). Spearman’s rank correlation coefficient (R) was used to assess the influence of various variables on maximum oxygen uptake (VO2max). The findings show that training of amateur long-distance XCS improved maximal oxygen uptake (p = 0.008) and had a positive effect on fat reduction, measured in percentages (p = 0.038) and in kilograms (p = 0.023), but did not change blood lipids or other parameters. Further research could focus on other aspects of the annual training cycle: the competition period, and women in a larger group of athletes. Training with roller skis and a cross-country skiing training machine (a specialized machine for strengthening the arms and upper body) can support health and prevent obesity, overweight, and cardiovascular disease.

The primary nutritional challenge facing endurance runners is meeting the nutrient requirements necessary to optimize the performance and recovery of prolonged training sessions. Supplement intake is a commonly used strategy by elite and recreational distance runners to meet nutritional recommendations. This study was conducted to investigate the patterns of supplement intake among different groups of distance runners and the potential association between supplement intake and sex, age, running and racing experiences. In a cross-sectional design, from a total of 317 runners participating in this survey, 119 distance runners were involved in the final sample after data clearance, assigned into three groups of 10-km runners (n = 24), half-marathoners (n = 44), and (ultra-)marathoners (n = 51). Personal characteristics, training and racing experiences, as well as patterns of supplement intake, including type, frequency, and dosage, were evaluated by questionnaire. Food Frequency Questionnaire was implemented to assess macronutrient intake. ANOVA and logistic regression were used for statistical analysis. While 50 % of total distance runners reported consuming supplements regularly, no differences between distance groups in consumption of carbohydrate/protein, mineral, or vitamin supplements were observed (p > 0.05). In addition, age, sex, running and racing experience showed no significant association with supplement intake (p > 0.05). Vitamin supplements had the highest intake rate in runners by 43 % compared to minerals (34 %) and carbohydrate/protein supplements (19 %). The present findings provide a window into the targeted approaches of long-distance runners as well as their coaches and sport nutrition specialists when applying and suggesting sustainable nutritional strategies for training and competition. Trial registration: ISRCTN73074080. Retrospectively registered 12th June 2015.

The relationship of body fat (BF) percentage with performance of elite marathon runners has been well studied, however, less information is available about the variation of skinfold thickness by sex and performance in non-elite marathon runners. The aim of the present study was to examine the variation of skinfold thickness by sex and performance in recreational marathon runners. Participants included 32 female (age 40.1 &plusmn, 9.0 years, BF 19.6 &plusmn, 4.7%, and training volume 47.7 &plusmn, 22.6 km) and 134 male marathon runners (44.3 &plusmn, 8.8 years, 17.6 &plusmn, 4.0%, and 53.0 &plusmn, 21.2 km, respectively). The largest skinfold thickness was the abdomen in both sexes, whereas the smallest was biceps in men, and chins in women (p &lt, 0.001). The largest sex difference in skinfold thickness was observed in triceps being the fattest in women (p &lt, 0.001). The largest difference in skinfold thickness among men&rsquo, s performance groups was observed in the iliac crest, and the smallest in the patella and proximal calf (p &lt, 0.001). In summary, skinfold measurements indicated that women had more fat in both their upper and lower limbs, while men had more fat in their trunk. With regards to the role of performance level, the slowest runners presented relatively more fat in the upper limbs and trunk anatomical sites, i.e., away from the active muscles of legs.

This paper proposes a new antenna remoting system for ultra-high frequency (UHF) radio frequency identification (RFID). The system consists of a central baseband controller and a remote antenna subsystem, which are connected using twisted-pair cable. During the inventory session, only baseband signals are transmitted over the twisted-pair cable, whilst the transmitted radio frequency (RF) signals are up and down converted in the antenna subsystem. This new RFID system provides −94.5 dBm of reader sensitivity, and can fulfill long-distance detection tasks with very low performance degradation over up to 150 m of Cat5et cable. Compared with conventional RFID systems using coaxial cables between reader and antenna, the presented RFID system is more flexible and cost-efficient due to its low deployment cost and ease of cable routing.

The Yangtze River Crossing Project, which is part of the Chinese gas pipeline trunk network and aims to transmit the natural gas to the Yangtze River Delta area, sets up a record for the length of Horizontal Directional Drilling (HDD) in the world. The term of pipeline installed is 3300m, and the diameter is 40in. Many technical difficulties have been inevitably encountered in a large diameter hole reaming in fine sand, the calculation of section scour depth which determines the minimum buried depth of the pipe, protection of outside coating and the method of long distance pilot hole drilling, such other challenges. In view of this, it was recommended that two pipelines of 711mm should be installed to replace the existing one of 1016mm in diameter and 1% flooding scour depth obtained by reliable statistical analysis. In period of installation, application glass fiber reinforced epoxy resin as a protective coating, executing the pilot hole by Intersect Method. As a result, this super project is finished successfully on May 21.2013. The experience can be applied to any pipeline engineering the installed by horizontal directional drilling or similar works.

Management of urban solid waste implies the collection, transfer, treatment recycle, reuse and disposal of such waste. Collection of urban household solid waste traditionally rests with government agencies designated with such responsibility. Solid waste collection begins from storage at the household level to the final treatment or disposal point and represents the most important aspect of urban solid waste management. Little has however been written on urban household solid waste collection in Nigeria. Using empirical data from three urban areas of Anambra State, Nigeria, the paper examines the place of informal private solid waste collectors in household solid waste collection. The ANOVA technique is used to test the null hypothesis that the sample means of the distance to designated community/street solid waste collection containers in the residential neighbourhoods of the three towns are equal. We conclude on household patronage of informal private solid waste collectors as against government provided community/street collection containers in the areas studied.

The Jiangyin Yangtze River Crossing Project sets up a record with the length of horizontal directional drilling (HDD) of 3300 m in the world. Inevitably, many technical difficulties might exist in pilot hole docking, reaming torque, property requirement and recovery of drilling fluids, and pullback resistance. Accordingly, some innovative measures were taken in each stage. At the pilot hole drilling stage, a reasonable drill tool assembly was chosen, namely, a new type of O 193.7 mm (S-135) drill pipe with high-strength was applied along with the fully guided cable and rotating magnate docking technologies. At the reaming stage, an innovative O 168.3 mm (V-150) drill pipe was adopted along with the optimized reamers and the improved hydraulic parameters to successfully reduce the reaming torque and significantly improve the reaming efficiency. At the pullback stage, a specific ground anchor was designed for large-tonnage pullback resistance, and drift pipe, super lubricants and novel glass fiber reinforced plastics were combined for protecting the pipeline coating. Finally, the drilling fluid formula was optimally selected to ensure the hole stability and flowback of drilling cuttings, and a centrifugal was used to recycle the drilling mud to ensure its necessary performance. All these measures not only ensured the success of this HDD project, but also broke many records in this respect.

To remedy the deficiency of the present monitoring systems in coal mine, this paper designs the integrated mine network composed of wireless sensor networks and other technologies, and analyzes the problems of wireless sensor networks applied in long distance roadway. Different from wireless sensor networks in common wide area environment, topology of network in long roadway is zonal structure, which leads the nodes near Sink to have high energy consumption and become “bottleneck node”. To improve the bottleneck phenomenon, strategies of uneven fixed cluster and Mixed routing based on the features of long roadway are proposed. Simulation based on Matlab shows that these strategies balance the global energy consumption and have a better performance on the network lifetime and connectivity, which proves they are suitable for mine environment.

Vacation travel in the USA, which constitutes about 25% of all long-distance travel, has been increasing consistently over the past two decades and warrants careful attention in the context of regional and statewide transportation air quality planning and policy analysis, as well as tourism marketing and service provision strategies. This paper contributes to the vacation travel literature by examining how households decide what vacation travel activities to participate in on an annual basis, and to what extent, given the total annual vacation travel time that is available at their disposal. To our knowledge, this is the first comprehensive modeling exercise in the literature to undertake such a vacation travel time-use analysis to examine purpose-specific time investments. A mixed multiple discrete-continuous extreme value (MDCEV) model structure that is consistent with the notion of “optimal arousal” in vacation type time-use decisions is used in the analysis. The data for the empirical analysis is drawn from the 1995 American Travel Survey (ATS). The results show that most households participate in different types of domestic vacation travel over the course of a year, and spend significantly different amounts of time on each type of vacation travel, based on household demographics, economic characteristics, and residence characteristics.

Based on the current state of technology, distance measurements over a few hundred metres in air with relative uncertainties significantly better than 10_6 are still an almost impossible challenge. In the European Joint Research Project (JRP) “Metrology for long distance surveying” measurement uncertainties in GNSS-based and optical distance metrology are going to be thoroughly investigated, novel technologies and primary standards developed and guidelines to improve surveying practice in the field worked out. A better understanding and a decrease of measurement uncertainty is also targeted for the critical local tie measurement at geodetic fundamental stations.

Lawrence Mbuagbaw,1,2 Lehana Thabane2,31Centre for the Development of Best Practices in Health (CDBPH), Yaoundé Central Hospital, Henri Dunant Avenue, Messa, Yaoundé, Cameroon; 2Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada; 3Biostatistics Unit, Father Sean O’Sullivan Research Centre, St Joseph's Healthcare, Hamilton, ON, CanadaAbstract: Mentoring plays an important role in learning and career development. Mentored researchers are more productive and more likely to publish their work. However, mentorship programs are not universally used in most settings or disciplines. Furthermore, successful and mutually beneficial mentoring relationships are not always easy to arrange. Long-distance mentoring relationships are even more difficult to handle and may break down for a wide variety of reasons. Drawing from our experiences with the first Canadian Institutes of Health Research – Canadian HIV Trials Network international postdoctoral fellowship program, we describe the roles of the context, the key mentor and the mentee attributes; goals and expectations; environments, local support, a communication plan, funding, face-to-face contact, multidisciplinary collaboration, co-mentoring, and evaluation as they apply to the successful implementation of a long-distance mentoring program.Keywords: long distance, mentoring, framework, Canada, Cameroon

Long-distance measurements (10 m - 1000 m) with an accuracy of 10-7 is a challenge for many applications. We show that it is achievable with Frequency Shifted Feedback (FSF) laser interferometry technique, provided that the determination of the radio frequency beat order be made without ambiguity and on a time scale compatible with atmospheric applications. Using the pulsed-FSF laser that we developed for laser guide star application, we propose and test, up to 240 m, a simple method for measuring the beat order in real time. The moving-comb and Yatsenko models are also discussed. The first of these models fails to interpret our long-distance interferometry results. We show that the accuracy of long-distance measurements depends primarily on the stabilization of the acoustic frequency of the modulator.

This paper describes the principle of precise length measurements using multi-wavelength interferometry. Three different examples are given in order to demonstrate PTB’s ability in this field: 1) Measurements of absolute distances up to 10 m performed by combination of the variable wavelength interferometry with fixed wavelength interferometry using two wavelengths simultaneously, 2) a three-wavelength diode laser interferometer for precision measurements of surface profiles (< 100 µm) and 3) PTB’s Precision Interferometer for length measurements of prismatic bodies, e.g. gauge blocks, using three wavelengths. The setup and principle of measurements and some results are presented and discussed in each case.