Prospects for Plug-in Hybrid Electric Vehicles in the United States and Japan: A General Equilibrium Analysis

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)The plug-in hybrid electric vehicle (PHEV) may offer a potential near term, low carbon alternative to today's gasoline- and diesel-powered vehicles. A representative vehicle technology that runs on electricity in addition to conventional fuels was introduced into the MIT Emissions Prediction and Policy Analysis (EPPA) model as a perfect substitute for internal combustion engine (ICE-only) vehicles in two likely early-adopting markets, the United States and Japan. We investigate the effect of relative vehicle cost and all-electric range on the timing of PHEV market entry in the presence and absence of an advanced cellulosic biofuels technology and a strong (450ppm) economy-wide carbon constraint. Vehicle cost could be a significant barrier to PHEV entry unless fairly aggressive goals for reducing battery costs are met. If a low cost vehicle is available we find that the PHEV has the potential to reduce CO2 emissions, refined oil demand, and under a carbon policy the required CO2 price in both the United States and Japan. The emissions reduction potential of PHEV adoption depends on the carbon intensity of electric power generation and the size of the vehicle fleet. Thus, the technology is much more effective in reducing CO2 emissions if adoption occurs under an economy-wide cap and trade system that also encourages low-carbon electricity generation.BP Conversion Research Project and the MIT Joint Program on the Science and Policy of Global Change through a consortium of industrial sponsors and Federal grants

Mid-upper arm circumference (MUAC) : new applications for an old measure

Mid-upper arm circumference (MUAC) has a long history as a simple and valuable anthropometric marker of undernutrition, of particular value in resource-poor settings.1 Traditionally, low MUAC has been seen as a proxy for low fat-free mass,1 necessary because accurate measurement of fat-free mass in children is usually impractical in both clinical settings and resource-poor settings. An emerging body of evidence suggests that MUAC may have value beyond its traditional application in the assessment of undernutrition. The paper by Whitfield et al2 notes that accurate measurement of body weight is often not possible in resource-poor settings, and this is important clinically because it substantially increases the risk of inaccurate drug dosage (where dosage is dependent on body weight). Whitfield et al2 describe a study which suggests that MUAC, when combined with other anthropometric measures, could be a useful and accurate way of estimating body weight in children. In a sample of 775 predominantly HIV positive children and adolescents (from 18 months to 12 years of age) from Botswana, Whitfield et al made a range of anthropometric measures (height or length, ulnar and tibial lengths, MUAC and triceps skinfold,

Comparison of accelerometer measured levels of physical activity and sedentary time between obese and non-obese children and adolescents: a systematic review

Background: Obesity has been hypothesized to be associated with reduced moderate-to-vigorous physical activity (MVPA) and increased sedentary time (ST). It is important to assess whether, and the extent to which, levels of MVPA and ST are suboptimal among children and adolescents with obesity. The primary objective of this study was to examine accelerometer-measured time spent in MVPA and ST of children and adolescents with obesity, compared with MVPA recommendations, and with non-obese peers. Methods: An extensive search was carried out in Medline, Cochrane library, EMBASE, SPORTDiscus, and CINAHL, from 2000 to 2015. Study selection and appraisal: studies with accelerometer-measured MVPA and/or ST (at least 3 days and 6 h/day) in free-living obese children and adolescents (0 to 19 years) were included. Study quality was assessed formally. Meta-analyses were planned for all outcomes but were precluded due to the high levels of heterogeneity across studies. Therefore, narrative syntheses were employed for all the outcomes. Results: Out of 1503 records, 26 studies were eligible (n = 14,739 participants; n = 3523 with obesity); 6/26 studies involved children aged 0 to 9 years and 18/26 involved adolescents aged 10.1 to19 years. In the participants with obesity, the time spent in MVPA was consistently below the recommended 60 min/day and ST was generally high regardless of the participant’s age and gender. Comparison with controls suggested that the time spent in MVPA was significantly lower in children and adolescents with obesity, though differences were relatively small. Levels of MVPA in the obese and non-obese were consistently below recommendations. There were no marked differences in ST between obese and non-obese peers. Conclusions: MVPA in children and adolescents with obesity tends to be well below international recommendations. Substantial effort is likely to be required to achieve the recommended levels of MVPA among obese individuals in obesity treatment interventions

Classification accuracy of body mass index for excessive body fatness in Kuwaiti adolescent girls and young adult women

Purpose: Adolescent obesity, as defined by BMI, is amongst the highest in the world in Kuwait. This study aimed to determine the extent to which BMI might be underestimating obesity as defined by excessive fatness in Kuwaiti female adolescents and young adults. Methods: A total of 400 apparently healthy Kuwaiti female university students (mean age 18.0 years, SD 0.6) were recruited. Excessive fatness was defined as body fat percentage ≥30, measured using the Tanita model TBF-310 Bio-impedance system with the manufacturer’s equation. Obesity was defined as recommended by the WHO in adult participants - those aged ≥19.1 years - as BMI≥30 kg/m2. In the adolescent participants (age <19.1 years) obesity was defined as recommended by the WHO as a BMI-for-age Z score of ≥2.00. The accuracy of BMI-defined obesity to identify excessively fat individuals was determined by estimating the prevalence of obesity using highBMI and prevalence of excessive fatness, and by calculating sensitivity and specificity and predictive values. Results: Median BMI was 27.8 kg/m2 (range 15.1-51.2) and median body fat percentage was 32.0 (range 5.0-54.0). The prevalence of excessive fatness was 62% (247/400 individuals were excessively fat), while the prevalence of obesity according toBMI was 42%(169/400 individuals were obese according to their BMI). The sensitivity of BMI to identify the excessively fat individuals was moderate (66%) but specificity was high (96%). The positive predictive value of BMI was 96% and the negative predictive value was 64%. Conclusion: BMI-based measures substantially underestimate the prevalence of excessive fatness in Kuwaiti adolescent females. Obesity is even more prevalent, and requires more urgent attention, than is apparent from BMI-based measures used in most research and national surveys. BMI may also be too crude for use as an exposure or outcome variable in many epidemiological studies of Arab adolescent girls and adult women

The piezoresistance of aluminum alloy interconnect structures

The effects of applied strain on the resistivity of Al thin film metallization interconnects have been measured with a novel methodology that uses thermal expansion mismatch to produce the strain. The interconnect volumetric strain is induced by thermal cycling of passivated and unpassivated interconnects between ≈70 and 373 K. The coefficient of piezoresistivity, defined as dρ/dϵvdρ/dϵv, where ρ=resistivity and ϵvϵv=volumetric strain, is determined by properly accounting for the degree of interconnect constraint and thermal expansion mismatch strain induced during temperature changes. The volumetric strains are calculated for unpassivated and passivated lines of varying thickness and width. A model which incorporates the geometrical and piezoresistance effects on the measured interconnect resistance during temperature changes is described. The coefficient of piezoresistivity is calculated by a fitting procedure which provides an accurate and consistent fit for both unpassivated and passivated interconnects of different geometries and different strain states. The measured coefficient dρ/dϵvdρ/dϵv is 2.0×10−52.0×10−5 Ω cm in tension, similar to earlier results in bulk Al samples measured in compression but significantly higher than values recently measured in Al interconnects. The application of the calibrated coefficient of piezoresistivity for the measurement of electromigration-induced stresses in novel interconnect test structures will be described. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70378/2/JAPIAU-85-3-1943-1.pd

An issue of permanence: assessing the effectiveness of temporary carbon storage

Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).In this paper, we present a method to quantify the effectiveness of carbon mitigation options taking into account the "permanence" of the emissions reduction. While the issue of permanence is most commonly associated with a "leaky" carbon sequestration reservoir, we argue that this is an issue that applies to just about all carbon mitigation options. The appropriate formulation of this problem is to ask 'what is the value of temporary storage?' Valuing temporary storage can be represented as a familiar economic problem, with explicitly stated assumptions about carbon prices and the discount rate. To illustrate the methodology, we calculate the sequestration effectiveness for injecting CO2 at various depths in the ocean. Analysis is performed for three limiting carbon price assumptions: constant carbon prices (assumes constant marginal damages), carbon prices rise at the discount rate (assumes efficient allocation of a cumulative emissions cap without a backstop technology), and carbon prices first rise at the discount rate but become constant after a given time (assumes introduction of a backstop technology). Our results show that the value of relatively deep ocean carbon sequestration can be nearly equivalent to permanent sequestration if marginal damages (i.e., carbon prices) remain constant or if there is a backstop technology that caps the abatement cost in the not too distant future. On the other hand, if climate damages are such as to require a fixed cumulative emissions limit and there is no backstop, then a storage option with even very slow leakage has limited value relative to a permanent storage option

Seasonal changes in objectively measured sedentary behavour and physical activity in Japanese primary school children

Background: The recent prevalence of obesity in Japanese children is much higher compared to 1980. The present study compared daily sedentary behavior (SB) and physical activity (PA) between the school year and summer vacation in Japanese primary school children. Methods: Participants were 98 Japanese boys (8.9 ± 1.8 years at baseline) and 111 girls (9.1 ± 1.8 years). SB and PA were measured in May (school term) and July/August (summer vacation), 2011. SB and PA were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare) for 7 consecutive days. The average number of minutes spent in SB (no more than 1.5 metabolic equivalents (METs)), light intensity activity (LPA; more than 1.5 to less than 3.0 METs) and moderate-to-vigorous physical activity (MVPA; 3.0 METs or more), and step counts were calculated for each individual. Moreover, the determinants/moderators of changes in SB and PA were examined. Results: Daily SB was significantly higher in the summer vacation than in the school year for both boys and girls (p < 0.05). Ambulatory and total LPA and MVPA, non-ambulatory LPA and step counts were lower in summer vacation in both genders (p < 0.001). Moreover, non-ambulatory MVPA was significantly lower in the summer vacation than in the school year for girls (p < 0.001). The decrease in non-ambulatory MVPA in boys and increase in SB in girls were significantly lower in those who participated in sports compared to those who did not (p < 0.040 or p < 0.033). The change in SB for boys was significantly associated with having a TV in the bedroom (p < 0.022). Conclusions: These findings show that primary school children in Japan are less active in the summer vacation, as indicated by both higher SB and lower LPA and ambulatory MVPA in both genders. Moreover, the seasonal change in non-ambulatory MVPA for Japanese children was affected by gender. This study also suggests that sports participation and bedroom TV ownership may moderate seasonal changes in PA and SB. The results emphasize the need to take summer vacation into account when planning interventions aimed at decreasing SB or increasing PA in Japanese children

Development and feasibility testing of an intervention to support active lifestyles in youths with Type 1 diabetes - the ActivPals programme : a study protocol

Background/objective: The global incidence of Type 1 diabetes is rising and youths with Type 1 diabetes continue to suffer poorer health than peers without diabetes. Evidence suggests youths with Type 1 diabetes have Physical Activity (PA) levels well below the recommendations for health and have high levels of sedentary behavior. An active lifestyle is therefore recommended to improve health. There is limited research showing effective lifestyle behavior change in this population, therefore an evidence gap exists between the need to promote physical activity in Type 1 diabetes care and lack of understanding on how to do this. This protocol paper describes a feasibility and pilot study of the ActivPals programme – an intervention to support active lifestyles in youths with Type 1 diabetes. Methods and design: Key intervention components have been identified from preliminary work (individual and family focus, peer mentoring, technology integration and improved communication and understanding) and are being developed into a pragmatic randomised controlled trial (RCT) supported by recruitment pathways. A steering group of health care professionals and managers will refine the intervention to patient needs. A pilot trial is providing data on intervention implementation, acceptability and feasibility. 20 youths with Type 1 diabetes are being recruited and randomised into an intervention or control group. Physical activity is being measured objectively using the Actigraph GT3X+ monitor at baseline and one month follow-up. Contextual factors associated with intervention delivery are being explored. Conclusions: This study will contribute to the development of evidence based, user informed and pragmatic interventions leading to healthier lifestyles in youths with Type 1 diabetes