Changes in population cholesterol levels and coronary heart disease deaths in seven countries

BACKGROUND: Are trends in coronary heart disease deaths based on risk factor changes? OBJECTIVE: To study the relationship between trends in coronary deaths and changes in blood cholesterol in the Seven Countries Study. MATERIAL AND METHODS: Sixteen cohorts of men aged 40-59 years from seven countries (U.S.A., Finland, the Netherlands, Italy, Croatia (former Yugoslavia), Serbia (former Yugoslavia), Greece, Japan) were units for the analyses of serum cholesterol measured at entry and after 5 and 10 years, and for mortality over 25 years. RESULTS: In the populations, the ecological relationship of mean serum cholesterol at entry to late coronary heart disease death rates during the 10- to 25-year follow-up was weak, with an R-square of 0.31. Cholesterol measurements made at year 10, and an indicator of cholesterol change during the first 10 years, increased the association (R-square, 0.49). A negative and significant interaction was shown between baseline population cholesterol levels and their 10-year change. As an indicator of acceleration in mortality, cholesterol change over 10 years was also positively correlated (partial R-square 0.44) with the ratio of 25-year to 5-year deaths. CONCLUSIONS: In the Seven Countries Study, late coronary heart disease death rates are largely "explained' by changes in blood cholesterol levels during the early phases of the study, mainly due to increases in lower cholesterol levels among some cohorts.     

Response of <Emphasis Type="Italic">Plutella xylostella</Emphasis> and its Parasitoid <Emphasis Type="Italic">Cotesia plutellae</Emphasis> to Volatile Compounds

The effects of limonene, a mixture of limonene + carvone (1:1, v/v), and methyl jasmonate (MeJA) on diamondback moth (DBM) (Plutella xylostella L.) oviposition, larval feeding, and the behavior of its larval parasitoid Cotesia plutellae (Kurdjumov) with cabbage (Brassica oleracea L. ssp. capitata, cvs. Rinda and Lennox) and broccoli (B. oleracea subsp. Italica cv Lucky) were tested. Limonene showed no deterrent effect on DBM when plants were sprayed with or exposed to limonene, although there was a cultivar difference. A mixture of limonene and carvone released from vermiculite showed a significant repellent effect, reducing the number of eggs laid on the cabbages. MeJA treatment reduced the relative growth rate (RGR) of larvae on cv Lennox leaves. In Y-tube olfactometer tests, C. plutellae preferred the odors of limonene and MeJA to filtered air. In cv Lennox, the parasitoid preferred DBM-damaged plants with limonene to such plants without limonene. C. plutellae females were repelled by the mixture of limonene + carvone. In both cultivars, exogenous MeJA induced the emission of the sesquiterpene (E,E)-α-farnesene, the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and green leaf volatile (Z)-3-hexenyl acetate + octanal. The attractive effect of limonene and MeJA predicts that these two compounds can be used in sustainable plant protection strategies in organic farming.     

Effect of cognitive load on speech prosody in aviation: Evidence from military simulator flights

Mental overload directly affects safety in aviation and needs to be alleviated. Speech recordings are obtained non-invasively and as such are feasible for monitoring cognitive load. We recorded speech of 13 military pilots while they were performing a simulator task. Three types of cognitive load (load on situation awareness, information processing and decision making) were rated by a flight instructor separately for each flight phase and participant. As a function of increased cognitive load, the mean utterance-level fundamental frequency (F0) increased, on average, by 7 Hz and the mean vocal intensity increased by 1 dB. In the most intensive simulator flight phases, mean F0 increased by 12 Hz and mean intensity, by 1.5 dB. At the same time, the mean F0 range decreased by 5 Hz, on average. Our results showed that prosodic features of speech can be used to monitor speaker state and support pilot training in a simulator environment.     

Effects of menu structure and touch screen scrolling style on the variability of glance durations during in-vehicle visual search tasks

The effects of alternative navigation device display features on drivers' visual sampling efficiency while searching forpoints of interest were studied in two driving simulation experiments with 40 participants. Given that the number of display items was sufficient, display features that facilitate resumption of visual search following interruptions were expected to lead to more consistent in-vehicle glance durations. As predicted, compared with a grid-style menu, searching information in a list-style menu while driving led to smaller variance in durations of in-vehicle glances, in particular with nine item displays. Kinetic touch screen scrolling induced a greater number of very short in-vehicle glances than scrolling with arrow buttons. The touch screen functionality did not significantly diminish the negative effects of the grid-menu compared with physical controls with list-style menus. The findings suggest that resumability of self-paced, in-vehicle visual search tasks could be assessed with the measures of variance of in-vehicle glance duration distributions. Statement of Relevance: The reported research reveals display design factors affecting safety-relevant variability of in-vehicle glance durations and provides a theoretical framework for explaining the effects. The research can have a significant methodical value for driver distraction research and practical value for the design and testing of in-vehicle user interfaces.     

Jitter characteristics of an on-chip voltage reference-locked time-to-digital converter

The noise and jitter characteristics of an on-chip voltage reference-locked ring oscillator used in the time-to-digital converter (TDC) of the integrated receiver of a pulsed time-of-flight laser rangefinder are presented. The frequency of the ring oscillator, 683 MHz, was locked to the on-chip voltage reference by means of a frequency-to-voltage converter, resulting in better than 90 ppm/°C stability. The noise and jitter transfer characteristics of the loop were derived, and simulations were performed to see the effects of different noise types (white and 1/f noise) on the cumulative jitter of the locked ring oscillator. Finally, these results were verified by jitter measurements performed using an integrated time-to-digital converter (TDC) fabricated on the same die (0.18 μm CMOS process). The cumulative jitter of the on-chip reference-locked ring oscillator was less than 30 ps (sigma value) over a time range of 70 ns, which made it possible to use this oscillator as the heart of a TDC when aiming at centimetre-level precision (1 cm = 67 ps) in laser ranging.     

From ideals towards practice: paradigmatic mismatches and drifts in method deployment

There is considerable debate in the information systems literature on how systems development methods (SDMs) are used in practice. On one side are those who take the position that these methods are not used at all. The other side posits that SDMs are used but not in the manner intended by the method developers. In practice, SDMs are adapted and modified to meet project exigencies, which results in unique methods‐in‐use in each project. We subscribe to the latter view and extend the argument by proposing that SDM modifications happen due to mismatches between the paradigmatic values inherent in the SDM, the method users and the organizational context. Further, planned modifications themselves result in shifts of paradigmatic values inherent in the SDM. To examine our contention, we conduct a case study in which we trace an SDM from its development to its deployment and use in an organization. We show where the mismatches occurred and provide explanations for the mismatches. Our results indicate that paradigm differences explain most of the mismatches, and different factors contribute to the paradigm drifts simultaneously, even towards diverging orientations. We conclude that the true value of an SDM, in addition to its tool and technique use, is a basis for examining and self‐reflecting about paradigmatic values. This is an essential part of learning to develop systems.     

Fast direct solution of the Helmholtz equation with a perfectly matched layer or an absorbing boundary condition

We consider the efficient numerical solution of the Helmholtz equation in a rectangular domain with a perfectly matched layer (PML) or an absorbing boundary condition (ABC). Standard bilinear (trilinear) finite‐element discretization on an orthogonal mesh leads to a separable system of linear equations for which we describe a cyclic reduction‐type fast direct solver. We present numerical studies to estimate the reflection of waves caused by an absorbing boundary and a PML, and we optimize certain parameters of the layer to minimize the reflection. Copyright © 2003 John Wiley & Sons, Ltd.