Diabet. Med. 30, 46–55 (2013)
Aims Whether long‐term cardiovascular risk is reduced by the Diabetes Prevention Program interventions is unknown. The aim of this study was to determine the long‐term ...differences in cardiovascular disease risk factors and the use of lipid and blood pressure medications by the original Diabetes Prevention Program intervention group.
Methods This long‐term follow‐up (median 10 years, interquartile range 9.0–10.5) of the three‐arm Diabetes Prevention Program randomized controlled clinical trial (metformin, intensive lifestyle and placebo), performed on 2766 (88%) of the Diabetes Prevention Program participants (who originally had impaired glucose tolerance), comprised a mean of 3.2 years of randomized treatment, approximately 1‐year transition (during which all participants were offered intensive lifestyle intervention) and 5 years follow‐up (Diabetes Prevention Program Outcomes Study). During the study, participants were followed in their original groups with their clinical care being provided by practitioners outside the research setting. The study determined lipoprotein profiles and blood pressure and medication use annually.
Results After 10 years’ follow‐up from Diabetes Prevention Program baseline, major reductions were seen for systolic (−2 to −3) and diastolic (−6 to −6.5 mmHg) blood pressure, and for LDL cholesterol (−0.51 to −0.6 mmol/l) and triglycerides (−0.23 to −0.25 mmol/l) in all groups, with no between‐group differences. HDL cholesterol also rose significantly (0.14 to 0.15 mmol/l) in all groups. Lipid (P = 0.01) and blood pressure (P = 0.09) medication use, however, were lower for the lifestyle group during the Diabetes Prevention Program Outcomes Study.
Conclusion Overall, intensive lifestyle intervention achieved, with less medication, a comparable long‐term effect on cardiovascular disease risk factors, to that seen in the metformin and placebo groups.
Aging has been associated with significant declines in the speed and accuracy of visual search. These effects have been attributed partly to low-level (bottom-up) factors including reductions in ...sensory acuity and general processing speed. Aging is also associated with changes in top-down attentional control, but the impact of these on search is less well-understood. The present study investigated age-related differences in top-down attentional control by comparing the speed and accuracy of saccadic sampling in the presence and absence of top-down information about target color in young (YA) and older (OA) observers. Displays contained an equal number of red and blue Landholt stimuli. Targets were distinguished from distractors by a unique orientation, and observers reported the direction of the target's gap on each trial. Single-target cues signaled the color of the target with 100% validity. Dual-target cues indicated the target could be present in either colored subgroup. The results revealed reliable group differences in the benefits associated with top-down information on single-target cues compared to dual-target cues. On single-target searches, OA made significantly more saccades than YA to stimuli in the uncued color subset. Single-target cues also produced a smaller advantage in the time taken to fixate the target in OA compared to YA. These results support an age-related decline in observers' use of top-down information to restrict sequences of saccades to a task-relevant subset of objects during visual search.
Public Significance Statement
Finding objects in the scene is a fundamental visual ability. Aging is associated with decreases in the speed and accuracy of this ability, and the current study suggests this reflects an age-related decline in the use of short-term memory to guide eye movements during search. This leads to a less effective search strategy in older adults, which is likely to impact the efficiency of everyday activities, such as driving or selecting items during online shopping.
Simultaneous search for two targets has been shown to be slower and less accurate than independent searches for the same two targets. Recent research suggests this 'dual-target cost' may be ...attributable to a limit in the number of target-templates than can guide search at any one time. The current study investigated this possibility by comparing behavioural responses during single- and dual-target searches for targets defined by their orientation. The results revealed an increase in reaction times for dual- compared to single-target searches that was largely independent of the number of items in the display. Response accuracy also decreased on dual- compared to single-target searches: dual-target accuracy was higher than predicted by a model restricting search guidance to a single target-template and lower than predicted by a model simulating two independent single-target searches. These results are consistent with a parallel model of dual-target search in which attentional control is exerted by more than one target-template at a time. The requirement to maintain two target-templates simultaneously, however, appears to impose a reduction in the specificity of the memory representation that guides search for each target.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The accuracy of state-of-the-art atomic clocks is derived from the insensitivity of narrow optical atomic resonances to environmental perturbations. Two such resonances in singly ionized lutetium ...have been identified with potentially lower sensitivities compared to other clock candidates. Here we report measurement of the most significant unknown atomic property of both transitions, the static differential scalar polarizability. From this, the fractional blackbody radiation shift for one of the transitions is found to be -1.36(9) × 10
at 300 K, the lowest of any established optical atomic clock. In consideration of leading systematic effects common to all ion clocks, both transitions compare favorably to the most accurate ion-based clocks reported to date. This work firmly establishes Lu
as a promising candidate for a future generation of more accurate optical atomic clocks.
We show that it is possible to significantly reduce rank 2 tensor shifts of a clock transition by operating at a judiciously chosen magnetic-field-insensitive point. In some cases shifts are almost ...completely eliminated making the transition an effective J=0 to J=0 candidate. This significantly improves the feasibility of a recent proposal for clock operation with large ion crystals. For such multi-ion clocks, geometric constraints and selection rules naturally divide clock operation into two categories based on the orientation of the magnetic field. We discuss the limitations imposed on each type and how calibrations might be carried out for clock operation.
A major role for visual short-term memory (VSTM) is to mediate perceptual comparisons of visual information across successive glances and brief temporal interruptions. Research that has focused on ...the comparison process has noted a marked tendency for performance to be better when participants are required to report a
difference
between the displays rather than report the absence of a difference (i.e. a
sameness
). We refer to this performance asymmetry as
report-difference superiority
(RDS). It has been suggested that RDS reflects the operation of a reflexive mechanism that generates a mismatch signal during the comparison of visual input with information maintained in VSTM. This bottom-up mechanism therefore gives evidence for the presence of a feature change but not for the absence of such a change; consequently, a sameness is harder to detect than a difference between two displays. We test this explanation, and determine whether by itself it is a sufficient explanation of the RDS. In a delayed comparison task we find the RDS effect is most prevalent when items retain the same display locations; however, the effect does persist even when compared item locations were scrambled across memory and test arrays. However, with a conjunction task this scrambling of locations was effective in wholly abolishing the RDS effect. We consider that the RDS effect is a consequence of local comparisons of features, as well as global statistical comparisons.
We demonstrate precision measurement and control of inhomogeneous broadening in a multi-ion clock consisting of three ^{176}Lu^{+} ions. Microwave spectroscopy between hyperfine states in the ...^{3}D_{1} level is used to characterize differential systematic shifts between ions, most notably those associated with the electric quadrupole moment. By appropriate alignment of the magnetic field, we demonstrate suppression of these effects to the ∼10^{-17} level relative to the ^{1}S_{0}↔^{3}D_{1} optical transition frequency. Correlation spectroscopy on the optical transition demonstrates the feasibility of a 10-s Ramsey interrogation in the three ion configuration with a corresponding projection noise limited stability of σ(τ)=8.2×10^{-17}/sqrtτ.
We make a detailed experimental study of the threshold for the self-organization of thermal 87Rb atoms coupled to a high-finesse cavity over a range of atom numbers and cavity detunings. We ...investigate the difference between probing with a traveling wave and a retroreflected lattice. These two scenarios lead to qualitatively different behavior in terms of the response of the system as a function of cavity detuning with respect to the probe. In both cases, we confirm a N(-1) scaling of the threshold with atom number.
Child-directed speech has long been known to influence children’s vocabulary learning. However, while we know that caregiver utterances differ from those directed at adults in various ways, little is ...known about any differences in the lexical properties of child-directed and adult-directed utterances. We compare over half a million word tokens from adult speech directed at children (from caregiver–child transcriptions) to the same quantity directed at adults. We show that child-directed speech contains greater numbers of words that are lower in phonemic length, higher in frequency, lower in phonotactic probability, and higher in neighborhood density than adult-directed speech; furthermore, child-directed speech explains over twice the variability of children’s productive noun vocabularies than adult-directed speech. These findings indicate that children’s word production is clearly influenced by the characteristics of the words spoken directly to them and that researchers need to be wary of using adult-directed language corpora when calculating lexical measures.
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