Associations between dietary added sugar intake and micronutrient intake: a systematic review

Original article can be found at: http://journals.cambridge.org/ Copyright The Authors. DOI: 10.1017/S0007114507617206There is increasing concern that high intakes of added sugars might compromise intakes of micronutrients. The objectives of this systematic review were (1) to determine whether dietary added sugar intake was associated with micronutrient intakes, and if so, whether there was evidence of micronutrient dilution as a result of higher dietary added sugar intake and (2) if micronutrient dilution was present, to determine whether there was sufficiently robust evidence to support a threshold effect above which there was a significant decline in micronutrient intake or status relative to the recommended intakes. A systematic computerised literature search was undertaken, limited to studies written in English published from 1980 onwards and further studies identified through hand searching papers. Fifteen studies that assessed associations between intakes of added sugars or non-milk extrinsic sugars and micronutrients were included. Overall, there are insufficient data and inconsistency between studies in relationships between added sugars and micronutrient intakes, with no clear evidence of micronutrient dilution or a threshold for a quantitative amount of added sugar intake for any of the micronutrients investigated. The current evidence base is considerably constrained by methodological issues. Further research is required to determine which food products high in added sugars might adversely affect micronutrient intakes by displacing other food items from the diet. Analyses should take into account the magnitude of any observed associations to determine their true biological significance.Peer reviewe

Tuning gastropod locomotion: Modeling the influence of mucus rheology on the cost of crawling

Common gastropods such as snails crawl on a solid substrate by propagating muscular waves of shear stress on a viscoelastic mucus. Producing the mucus accounts for the largest component in the gastropod's energy budget, more than twenty times the amount of mechanical work used in crawling. Using a simple mechanical model, we show that the shear-thinning properties of the mucus favor a decrease in the amount of mucus necessary for crawling, thereby decreasing the overall energetic cost of locomotion.Comment: Corrected typo

Will spin-relaxation times in molecular magnets permit quantum information processing?

Using X-band pulsed electron spin resonance, we report the intrinsic spin-lattice ($T_1$) and phase coherence ($T_2$) relaxation times in molecular nanomagnets for the first time. In Cr$_7M$ heterometallic wheels, with $M$ = Ni and Mn, phase coherence relaxation is dominated by the coupling of the electron spin to protons within the molecule. In deuterated samples $T_2$ reaches 3 $\mu$s at low temperatures, which is several orders of magnitude longer than the duration of spin manipulations, satisfying a prerequisite for the deployment of molecular nanomagnets in quantum information applications.Comment: 4 pages, 3 figures, in press at Physical Review Letter

Monte Carlo studies of a novel X-ray tube anode design

When energetic electrons are incident on high atomic number absorbers, a substantial fraction is back-scattered. This phenomenon is responsible for several undesirable effects in X-ray tubes, in particular a reduction in the X-ray output. The extent of this shortfall has been estimated by using Monte Carlo simulation to start electrons at increasing depth inside the anode, the results indicating that an output enhancement of nearly 50% could be achieved in principle if the electrons wasted in back-scatter events could be trapped inside a tungsten anode. To test this idea a further set of simulations were done for a novel anode geometry. Results showed that X-ray tube efficiencies might be substantially enhanced by this approach.http://www.sciencedirect.com/science/article/B6TVT-43P41Y7-30/1/526566f6ea15332c302cdad2886e583

Host isotope mass effects on the hyperfine interaction of group-V donors in silicon

The effects of host isotope mass on the hyperfine interaction of group-V donors in silicon are revealed by pulsed electron nuclear double resonance (ENDOR) spectroscopy of isotopically engineered Si single crystals. Each of the hyperfine-split P-31, As-75, Sb-121, Sb-123, and Bi-209 ENDOR lines splits further into multiple components, whose relative intensities accurately match the statistical likelihood of the nine possible average Si masses in the four nearest-neighbor sites due to random occupation by the three stable isotopes Si-28, Si-29, and Si-30. Further investigation with P-31 donors shows that the resolved ENDOR components shift linearly with the bulk-averaged Si mass.Comment: 5 pages, 4 figures, 1 tabl

Landscape-scale variation in forest structure and biomass along an elevation gradient in the Atlantic Forest of the Serra do Mar, Brazil.

Landscape-scale quantification of forest structure, disturbance patterns and biomass distribution can improve our understanding of the environmental controls on the functioning of forested ecosystems. Assessing the detailed structure of the complex tropical forest canopy is a challenging task, especially in areas of steep topography where field access is limited. We used airborne lidar (light detection and ranging) data to describe the landscape-scale variation in canopy structure and gap distribution in a 1000-ha area along an elevation gradient from 0 to 1200m in the Atlantic Forest of the Serra do Mar in southeast Brazil. Mean canopy heights (MCHs) were greatest (21-22m) at intermediate elevations (200-700m) in the submontane forest where terrain slope was also the steepest (~40º). Canopy gap fraction was highest (~30%) and MCH lowest (~16m) in the montane forest areas (900-1100m) on flatter sites atop the plateau (~24º slopes). We used forest inventory data from nine 1-ha permanent field plots (PFPs) within the study area to assess aboveground biomass (AGB) stocks and changes. We established regression models based on lidar-derived canopy structure and field-based biometry data, and used these to extrapolate AGB predictions across the landscape. Comparing canopy height and disturbance distributions in the PFPs with the distributions across the broader landscape, we found that submontane PFPs showed closer correspondence with their surrounding areas, while montane PFPs consistently overestimated landscape-scale canopy height (thus AGB pools) and underestimated gap fraction (therefore AGB changes)

The White Dwarf in EM Cygni: Beyond The Veil

We present a spectral analysis of the FUSE spectra of EM Cygni, a Z Cam DN system. The FUSE spectrum, obtained in quiescence, consists of 4 individual exposures (orbits): two exposures, at orbital phases phi ~ 0.65 and phi ~ 0.90, have a lower flux; and two exposures, at orbital phases phi =0.15 and 0.45, have a relatively higher flux. The change of flux level as a function of the orbital phase is consistent with the stream material (flowing over and below the disk from the hot spot region to smaller radii) partially masking the white dwarf. We carry out a spectral analysis of the FUSE data, obtained at phase 0.45 (when the flux is maximual, using the codes TLUSTY and SYNSPEC. Using a single white dwarf spectral component, we obtain a white dwarf temperature of 40,000K, rotating at 100km/s. The white dwarf, or conceivably, the material overflowing the disk rim, shows suprasolar abundances of silicon, sulphur and possibly nitrogen. Using a white dwarf+disk composite model, we obtain that the white dwarf temperature could be even as high as 50,000K, contributing more than 90% of the FUV flux, and the disk contributing less than 10% must have a mass accretion rate reaching 1.E-10 Msun/yr.In both cases, however, we obtain that the white dwarf temperature is much higher than previously estimated.Comment: accepted for publication in ApJ, 3 Tables, 12 Figures (including color figures), 33 pages in present format (possibly 10 pages in ApJ format

Opening up the Quantum Three-Box Problem with Undetectable Measurements

One of the most striking features of quantum mechanics is the profound effect exerted by measurements alone. Sophisticated quantum control is now available in several experimental systems, exposing discrepancies between quantum and classical mechanics whenever measurement induces disturbance of the interrogated system. In practice, such discrepancies may frequently be explained as the back-action required by quantum mechanics adding quantum noise to a classical signal. Here we implement the 'three-box' quantum game of Aharonov and Vaidman in which quantum measurements add no detectable noise to a classical signal, by utilising state-of-the-art control and measurement of the nitrogen vacancy centre in diamond. Quantum and classical mechanics then make contradictory predictions for the same experimental procedure, however classical observers cannot invoke measurement-induced disturbance to explain this discrepancy. We quantify the residual disturbance of our measurements and obtain data that rule out any classical model by > 7.8 standard deviations, allowing us for the first time to exclude the property of macroscopic state-definiteness from our system. Our experiment is then equivalent to a Kochen-Spekker test of quantum non-contextuality that successfully addresses the measurement detectability loophole