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PubMed1981

[Our parents too are commuters].

Elderly persons (over the age of 60) suffer traffic accidents more frequently than it could be expected considering their incidence rate in the population all over the world. The situation in Hungary is least favourable since the number of traffic accident victims (pedestrians) is extremely high. This endangerment of elderly persons may be explained by their mental and physical condition and behaviour. The important duty of the society to improve by all means the situation of elderly persons in the traffic.

Accidents, Traffic↗
PubMed1998

Commutability of control materials in glycohemoglobin determinations.

The intermethod variabilities of control materials and patient blood samples for the measurement of glycohemoglobin were compared. Sets of 50 blood samples and 15 control materials were analyzed by HPLC and affinity and immunochemical methods. For each pair of methods, the distances of the materials from the regression line of patient blood results (expressed as normalized residuals) were calculated. Only two of 15 controls had normalized residuals exceeding 3 standard deviations from the regression line. Total hemoglobin (Hb) content, Hb derivatives, and cellulose acetate electrophoresis demonstrated that only a minority of controls could be considered similar to patients' blood samples. We selected Menarini's and our home-prepared controls to simulate calibration of the different techniques by these materials. Intermethod calibration succeeded mostly in harmonizing results obtained by HPLC methods. On the contrary, calibration of the immunochemical techniques (Boehringer and Roche) did not improve intermethod agreement to a clinically useful level.

Chromatography, Affinity↗
PubMed2004

Does the cue help? Children's understanding of multiplicative concepts in different problem contexts.

BACKGROUND: Understanding arithmetical principles is a key part of a conceptual understanding of mathematics. However, very little attention has been paid to children's understanding of multiplicative, as compared to additive, principles. AIMS: This study investigated (a) children's ability to use commutative and distributive cues to solve multiplication problems, (b) whether their ability to use these cues depends on the problem context, and (c) whether separate mechanisms might underlie children's understanding of commutativity and distributivity. SAMPLE: Twenty-seven 9-year-olds (Year 5) and thirty-two 10-year-olds (Year 6). METHODS: Forty-eight multiplication problems (with a multiple-choice response format) were presented to children. There were four types of problem: Commutative, Distributive, Combined commutative-distributive (all preceded by a cue) and No cue problems. Each type of problem was presented in three different contexts: Isomorphism of measures, Area, and Cartesian product. RESULTS: Children demonstrated a good understanding of commutativity but a very poor understanding of distributivity. A common mistake in the distributive problems was to select the number that was one more, or one less, than the answer in the cue. Children's understanding of distributivity (but not commutativity) seemed to depend on the problem context. Factor analysis suggested that separate factors underlie the ability to solve commutative and distributive problems. CONCLUSIONS: Nine- and 10-year-olds understand commutativity, but are unable to use the distributive principle in multiplication. Their errors suggest that they may confuse some of the principles of multiplication with those of addition. When children do begin to understand the principle of distributivity, they most easily apply it in the context of Isomorphism of measures multiplication problems. The implications for mathematical education are discussed.

Child↗
PubMed1995

Perceived risk and modal choice: risk compensation in transportation systems.

A transportation mode choice analysis is performed that examines behavioral responses to perceived risk in the choice of mode for daily commute trips. This methodology provides a technique for examining, by means of disaggregate individual level data, risk-compensating effects in transportation systems. Various measures of perceived risk are examined for explaining modal choice. Other studies have described how safety regulations have resulted in increases in "driving intensity." This study defines one component of driving intensity to be the increased probability of commuting by automobile. The results show that modal shifts occur when risk perceptions for a given mode are reduced. To demonstrate potential risk-compensating effects within the transportation system, an estimate of changes in accident fatalities due to commuting is derived using rough estimates of fatalities per person-mile travelled. It is shown that a given change in the perceived risk of commuting by automobile results in a less than proportionate change in net commuting fatalities. The relative magnitude is dependent on how objective reductions in risk translate into perceived reductions in risk. This study also shows that perceived safety improvements in bicycle transportation have an aggregate elasticity value that is greater than one. This means that bicycle safety improvements attract proportionately more people to bicycle commuting (i.e. a 10% increase in safety results in a greater than 10% increase in the share of people bicycle commuting).

Accidents, Traffic↗
PubMed2001

Myoglobin and creatine kinase isoenzyme MB mass assays: intermethod behaviour of patient sera and commercially available control materials.

The low biological variation of myoglobin and creatine kinase isoenzyme MB mass (CK-MBm) requires accurate measurements. In the standardization process, in order to effectively measure and correct intermethod variability, the intermethod behaviour of control materials must be the same of patient sera, i.e. they must be commutable. In this work we checked the commutability of some commercially available control materials in pairs of methods for myoglobin and CK-MBm measurements; we assessed the impact of commutable and non-commutable control materials when used for equalizing patient sera results by two different methods and discussed the problems related to external quality assessment schemes. Myoglobin and CK-MBm were measured in sets of 49 and 56 patient sera and in 13 commercially available control materials with two automatic analytical systems. The non-commutability rate was 8.3% for myoglobin and 23.1% for CK-MBm. Recalculation of serum samples results with a control material as calibrator lowered or increased the bias originally present according to whether the material itself was commutable or not. We conclude that also for myoglobin and CK-MBm assays it is necessary to check the commutability of materials to be used in external quality assessment schemes, or to normalize patient results by different methods.

Creatine Kinase↗
PubMed2006

Active transportation to school over 2 years in relation to weight status and physical activity.

OBJECTIVE: To prospectively examine potential benefits of active commuting to school on measures of weight status and physical activity in a sample of youth. RESEARCH METHODS AND PROCEDURES: A cohort of students from seven elementary schools was measured four times--in the fall and spring of fourth grade (N = 1083) and fifth grade (N = 924). Participants were classified as active (walking, biking, or skateboarding to school almost every day for baseline analyses or at least 2 d/wk for analyses of consistent active commuting) or non-active commuters to school. Accelerometers were used to measure physical activity. Height, weight, and skinfolds were objectively assessed. RESULTS: Boys who actively commuted to school had lower BMI (p < 0.01) and skinfolds (p < 0.05) than non-active commuters to school in the fourth grade. Active commuting to school over 2 years was not associated with BMI change or overweight status. DISCUSSION: Walking and cycling to school may contribute to preventing excessive weight gain, or leaner children may walk or cycle to school.

Analysis of Variance↗