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At least 127 records · Page 7Linked to original sources
PubMed2006

Studies on commuters' exposure to BTEX in passenger cars in Kolkata, India.

Commuters' exposure to volatile organic compounds (VOCs) especially BTEX travelling in passenger cars in Kolkata, India were quantified in Phase I (2001-2002) and Phase II (2003-2004). Monitoring was made inside and in the immediate outside of passenger cars fitted with and without catalytic converters using different types of fuels, along two congested urban routes. During Phase I of the study, the benzene content in gasoline was 5% and the mean concentration of in-vehicle benzene in cars without catalytic converter was found to be as high as 721.2 microg/m3. In Phase II when the benzene content was reduced to <3% and with modified engine type, the mean in-vehicle benzene concentration was reduced to 112.4 microg/m3. The in-vehicle concentration varied with engine type and age of the vehicle. Roadside ambient mean concentration of benzene was 214.8 microg/m3 and 30.8 microg/m3 in Phase I and Phase II respectively.

Air Pollutants↗
PubMed2004

Boarding and alighting injury experience with different station platform and car entranceway designs on US commuter railroads.

Commuter railroad systems in the US employ three combinations of station platforms and car entranceways. These are high-level platforms with remotely controlled doors and level entranceway (HL-RC), low-level platforms (just above the rail) with steps and remotely controlled doors (LL-RC), and a mixture of the two platform types with a correspondingly more complex, partly manual, door and entranceway arrangement (ML-MO). Much controversy exists over which type of platform/entranceway is better. This seemingly small feature significantly impacts many performance characteristics of these systems, including cost, speed, and boarding and alighting accidents. Northeastern systems are generally moving toward the mixed platform design or all high-level platforms, while systems elsewhere are generally selecting the low-level design. Data on actual accident experience for 1995-2000 are analyzed to determine the effect of platform/entranceway type on passenger and employee injuries. Passenger injury rates on systems with the HL-RC design are lowest, with LL-RC systems next, and ML-MO systems having the highest rates. Employee injury rates are the least on LL-RC systems, but higher on ML-MO and HL-RC systems. Systems with a mixture of high and low platforms (ML-MO) experience a higher overall (combined passenger and employee) injury rate than the other two designs. The implications of these results for both the modernization of existing systems and the design of new systems, in the US and abroad, are discussed.

Accidents, Occupational↗
PubMed1998

Ottawa-Carleton commuter cyclist on- and off-road incident rates.

This analysis overcomes the known limitations of police and emergency room bicycle accident databases through use of a survey that asked cyclists to indicate their accident history as well as their regular commute route to work or school. By relating the route information of the 1604 respondents (52.5% of the distributed questionnaires) to facility attributes in a Geographic Information System, defensible estimates of travel exposure on roads, off-road paths and sidewalks were developed. The relative rates of collisions on the three different facility types were not statistically different from 1.0. The relative rates for falls and injuries suggest it is safest to cycle on-road followed by off-road paths and trails, and finally least safe on sidewalks. While there were no major injuries reported on sidewalks, the relative rate for these events on paths was greater than the rate for roads. The absolute event rates per bicycle kilometre were found to be between 10 and 41 times higher than similar rates for automobile travel. Results suggest a need to discourage sidewalk cycling, and to further investigate the safety of off-road paths/trails. The analysis also demonstrates the need for bicycle travel exposure information and the use of more than just collision databases for bicycle safety analysis.

Accident Prevention↗
PubMed2001

Miniature motorized microdrive and commutator system for chronic neural recording in small animals.

The use of chronically implanted electrodes for neural recordings in small, freely behaving animals poses several unique technical challenges. Because of the need for an extremely lightweight apparatus, chronic recording technology has been limited to manually operated microdrives, despite the advantage of motorized manipulators for positioning electrodes. Here we describe a motorized, miniature chronically implantable microdrive for independently positioning three electrodes in the brain. The electrodes are controlled remotely, avoiding the need to disturb the animal during electrode positioning. The microdrive is approximately 6 mm in diameter, 17 mm high and weighs only 1.5 g, including the headstage preamplifier. Use of the motorized microdrive has produced a ten-fold increase in our data yield compared to those experiments done using a manually operated drive. In addition, we are able to record from multiple single neurons in the behaving animal with signal quality comparable to that seen in a head-fixed anesthetized animal. We also describe a motorized commutator that actively tracks animal rotation based on a measurement of torque in the tether.

Action Potentials↗
PubMed2003

Commuting to school: are children who walk more physically active?

BACKGROUND: The journey to school is an opportunity for increasing children's daily physical activity. However, the contribution that active commuting to school makes to overall physical activity is unknown. This study used objective measurement to investigate the physical activity patterns of children by mode of travel to school. METHODS: Primary-school children wore an accelerometer programmed to record minute-by-minute physical activity for 7 days and completed a brief questionnaire describing their usual travel to school. The total volume of physical activity and the time spent in activity of at least moderate intensity, as recorded by the accelerometer, was estimated for weekdays and the weekend, and groups of children were compared by mode of transport to school. Data were collected in May/June 2002. RESULTS: Of the 114 children (59 boys, 55 girls; aged 10.4+/-0.8 years) who took part in the study, those who walked to school (65%) were significantly more active than those who traveled by car (712.0+/-206.7 vs 629.9+/-207.2 accelerometer counts per minute, p=0.05). Analysis by gender indicated that the major differences in physical activity between travel groups were seen only in boys. Hourly activity patterns demonstrated that boys who walked to school were more active after school and throughout the evening than were car users. CONCLUSIONS: In boys, walking to school was associated with higher physical activity after school and during the evening. Active transport may contribute to a more physically active profile, at least for boys, supporting walk-to-school initiatives to increase children's physical activity.

Child↗
PubMedDate not supplied

Urban commuter exposure to particle matter and carbon monoxide inside an automobile.

In-vehicle exposures to different sizes of particles and carbon monoxide (CO) were determined while driving along a standardized route under a variety of traffic conditions in Kuopio, Finland during the 12-month period from January to December 1995. Arithmetic means of in-vehicle exposures during the morning rush hours were 5.7 parts per million (ppm) (geometric mean, GM = 3.1 ppm, geometric standard deviation, GSD = 1.7) for CO, 107 #/cm3 (GM = 75 #/cm3, GSD = 1.9) for fine particles (optical equivalent particle size range 0.3-1 micron) and 0.9 #/cm3 (GM = 0.6 #/cm3, GSD = 2.1) for coarse particles (optical equivalent particle size range 1-10 microns). Fine particles and CO behaved similarly in different weather and traffic conditions, while the behavior of coarse particles was usually different, and often opposite. The driving conditions that affected the passengers' exposures to CO and fine particles were the time of day (morning vs. afternoon) and average speed (decreasing). The meteorological parameters that affected the passengers' exposures to CO and fine particles were wind speed (decreasing) and relative humidity (increasing). Wind speed, relative humidity and driving speed all had opposite effects on the exposure levels to fine vs. coarse particles. Added exposures (due to commuting on top of the background levels) to CO and fine particles were considerably higher in the morning vs. the afternoon runs and also higher in the slower vs. the faster runs.

Air Pollution, Indoor↗
PubMed1999

On the classification of binary shifts of minimal commutant index.

We provide a complete classification up to conjugacy of the binary shifts of commutant index 2 on the hyperfinite II(1) factor. There is a natural correspondence between the conjugacy classes of these shifts and polynomials over GF(2) satisfying a certain duality condition.

Journal Article↗
PubMed1999

On the classification of binary shifts of finite commutant index.

We provide a complete classification up to conjugacy of the binary shifts of finite commutant index on the hyperfinite II(1), factor. There is a natural correspondence between the conjugacy classes of these shifts and polynomials over GF(2) satisfying a certain duality condition.

Journal Article↗
PubMed1976

Urban commuting: crowdedness and catecholamine excretion.

Male passengers regularly commuting by train on the Stockholm-Nynäshamn line were investigated on two morning trips to Stockholm. These trips were made under different levels of crowding, before (Trip 1) and after (Trip 2) a period of gas rationing during the oil crisis in 1974. However, seats were available for almost everyone during both trips. One group of subjects boarded the train at its first stop (Nynäshamn), the other midway on its route (Västerhaninge). Physiological reactions were assessed from the rate of catecholamine excretion in urine and subjective experiences were measured by self-ratings. The results showed that feelings of discomfort grew more intense as the train approached Stockholm and the number of passengers increased. Perceived crowdedness increased as the square of the number of passengers. During both trips the subjects from Nynäshamn (longer trip) had a lower rate of adrenaline and noradrenaline excretion on the train than those from Västerhaninge. Furthermore, it was found that the rate of adrenaline excretion was higher for both groups during Trip 2, when the train was more crowded. The results support previous findings indicating that the stress involved in travelling by train varies more with the social and ecological conditions of the trip than with its length or duration.

Adult↗
PubMed1998

Sexual behaviors and safer sex practices of college students on a commuter campus.

The sexual behaviors and safer sex practices of college students at a midwestern commuter university are described. Responses from a student sample of 1,919 indicated that slightly more than 10% used condoms consistently. The most frequently cited reasons for not using condoms were monogamy (83%) and preferring other forms of birth control (31%). The leading reason for consistent condom use was fear of HIV infection (72%). Approximately 75% indicated they talked with their sexual partners about HIV prevention; women reported communicating significantly more often than men did (p < 0.0001). Seventy percent of the sample reported they had only one sexual partner during the past year. Students who had multiple partners during the past year were more likely to practice such unsafe sexual practices as not using condoms and not communicating about HIV prevention. Unsafe sexual practices occur on nontraditional university campuses just as frequently as they do on more traditional campuses, thus supporting the need for HIV prevention programs on every college and university campus.

Adolescent↗
PubMed2006

Delayed commutation in quantum computer networks.

In the same way that classical computer networks connect and enhance the capabilities of classical computers, quantum networks can combine the advantages of quantum information and communication. We propose a nonclassical network element, a delayed commutation switch, that can solve the problem of switching time in packet switching networks. With the help of some local ancillary qubits and superdense codes, we can route a qubit packet after part of it has left the network node.

Journal Article↗
PubMed2000

Inter-method differences and commutability of control materials for HbA2 measurement.

The intermethod variability of control materials and patient blood samples for the measurement of hemoglobin A2 (HbA2) were compared. A set of 54 blood samples and 10 control materials were analyzed in duplicate by HPLC and microcolumn methods. For each set of methods the distances of the materials from the regression line of patient blood results (expressed as normalized residuals) were calculated. Four out of ten controls had normalized residuals exceeding three standard deviations from the regression line. Moreover, total Hb and Hb derivatives analysis proved that only a minority of the controls could be considered similar to patients' blood samples. Intermethod calibration performed "a posteriori" by the two best performing control materials improved intermethod variability among all the five tested methods. We conclude that the use of high resolution HPLC methods together with appropriate commutable control materials allows for better harmonization of results in the field of diagnosis of hemoglobin disorders in research and clinical practice.

Calibration↗
PubMed2001

Commutability of serum protein values: persisting bias among manufacturers using values assigned from the certified reference material 470 (CRM 470) in the United States.

Significant among-manufacturer differences in values for serum proteins persist 7 years after the introduction of the international reference material (Certified Reference Material 470; Reference Preparation for Proteins in Human Serum). In some cases, such as transthyretin and C4, the biases actually continue to increase. Further efforts at standardization are needed in order to improve commutability of results among laboratories and are essential if universal reference intervals are to be developed.

Blood Proteins↗
PubMed2003

Commutability of the CRM 470 C-reactive protein value in the Dade Behring N High Sensitivity CRP assay.

Certified Reference Material 470 (CRM 470) demonstrates commutability with both the manufacturer's calibrator and with dilutions of serum pools in the Dade Behring N High Sensitivity assay for C-reactive protein (CRP). Both regression and back calibration show similar nonlinearity for all materials, largely due to the method of calibration curve fitting used in this assay. Significant differences in values among the currently available commercial assays can be largely overcome by using appropriate calibration curve fitting and the recommended value transfer protocol, which includes a minimum of two assay runs on each of at least 3 separate days, with weight correction of all reconstitutions and dilutions. An initial weight-corrected dilution should be made each day because of the relatively high level of CRP in CRM 470. In our opinion, the degree of nonlinearity, imprecision, and differences in values in currently available assays renders the use of fixed clinical decision cut-points questionable for high-sensitivity CRP. An alternative approach is suggested.

C-Reactive Protein↗
PubMedDate not supplied

Assessing the risk factors for suicidal thoughts at a nontraditional commuter school.

The sample of students completing the National College Health Assessment (NCHA) Survey at the University of Utah differs from the national reference group for the NCHA 2003 in age, employment, residence, and marital status. The purpose of this study is to determine if the defining characteristics of a commuter school increase the risk for suicidal thoughts. During the fall semester of 2004, the University of Utah implemented a randomized electronic survey assessing the student body's health status in several areas. The authors compared 88 respondents who endorsed seriously considered suicide in the previous 12 months were with the remaining 954 respondents to identify discriminating variables. Those students who seriously considered suicide more likely lived off campus, indicated they were emotionally abused, were in only fair health, experienced being assaulted, experienced unwanted sexual touching, or were not heterosexual. Students who were employed were significantly less likely to consider suicide.

Adolescent↗
PubMedDate not supplied

Effect of Australia's Walk to Work Day campaign on adults' active commuting and physical activity behavior.

PURPOSE: To determine whether Australia's Walk to Work Day media campaign resulted in behavioral change among targeted groups. METHODS: Pre- and postcampaign telephone surveys of a cohort of adults aged 18 to 65 years (n = 1100, 55% response rate) were randomly sampled from Australian major metropolitan areas. Tests for dependent samples were applied (McNemar chi2 or paired t-test). RESULTS: Among participants who did not usually actively commute to work was a significant decrease in "car only" use and an increase in walking combined with public transport. Among those who were employed was a significant increase in total time walking (+ 16 min/wk; t [780] = 2.04, p < .05) and in other moderate physical activity (+120 min/wk; t [1087] = 4.76, p < .005), resulting in a significant decrease in the proportion who were "inactive" (chi2 (1) = 6.1, p <.05). CONCLUSION: Although nonexperimental, the Walk to Work Day initiative elicited shortterm changes in targeted behaviors among target groups. Reinforcement by integrating worksite health promotion strategies may be required for sustained effects.

Adolescent↗
PubMed1999

Commuting to high altitude. Recent studies of oxygen enrichment.

Further studies have been carried out on the potential value of oxygen enrichment of room air for commuters to high altitude. Novel ways of providing oxygen-enriched spaces for working and sleeping are being tested at the California Institute of Technology where a radiotelescope is being designed for an altitude of 5,000 m in north Chile. The modules are containers such as those used on container ships, and they are fitted out in California and then sealed and transported to the telescope site in Chile. The result is a turnkey facility which shows promise for field studies. The oxygen is provided by oxygen concentrators, and different modules are used for sleeping, living, and laboratory quarters. Two extensive experiments on oxygen enrichment were carried out at the University of California White Mountain Research Station, altitude 3,800 m, in the summer of 1998. The first study was devoted to the mechanism for the increase in arterial oxygen saturation on the day after sleeping in an oxygen-enriched atmosphere compared with sleeping in ambient air (5). Possible mechanisms include less fluid accumulation in the lung associated with acute mountain sickness, or a change in the control of ventilation. A double blind study was therefore carried out of the effects of sleeping in oxygen enrichment on both the ventilatory response to hypoxia and to carbon dioxide. In a related study, subjects who had been at an altitude of 3,800 m for two days, and were therefore partially acclimatized, were studied at a simulated altitude of 5,000 both breathing ambient air and 27% oxygen. The studies were done at 3800 m altitude by enriching the atmosphere of the test room with appropriate amounts of nitrogen or oxygen. An extensive series of neuropsychological tests were carried out with the objective of determining which features of CNS function were improved by oxygen enrichment at an altitude of 5,000 m.

Altitude↗