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Breastfeeding may reduce obesity risk, but this association could be confounded by breastfeeding families’ characteristics. We investigated if body composition differs at birth among infants who were either exclusively breast- or formula-fed. We hypothesized the two groups would differ in body composition, even at birth, prior to their post-natal feeding experience. Healthy primiparous carrying singleton pregnancy were recruited at 15 weeks’ gestation. PEA POD® measured body composition within 72 hours of delivery and infant feeding was prospectively captured. Out of the 1,152 infants recruited, 117 (10.2%) and 239 (20.7%) went on to be either exclusively breast- or formula-fed, respectively. Breastfed infants were heavier at birth, but their percentage fat mass (FM) was lower than that of exclusively formula-fed infants (covariate adjusted β = −1.91 percentage points of FM; 95% CI −2.82 to −1.01). Differences in intra-uterine exposures, irrespective of early diet, may partly explain an infant’s obesity risk.
Qualitative inorganic analysis is required for the identification of unknowns, the classification of type, and sometimes to decide what subsequent quantitative analysis is needed. The traditional way of performing qualitative XRF analysis on unknown materials is by subjecting the sample to a full spectral scan. This takes time and an experienced operator to interpret the spectra. Classifying the elements detected as major, minor or trace can also be person dependent. Round robin tests have confirmed this by showing considerable variation in results between laboratories.
The first meeting of the IntCal04 working group took place at Queen's University Belfast from April 15 to 17, 2002. The participants are listed as co-authors of this report. The meeting considered criteria for the acceptance of data into the next official calibration dataset, the importance of including reliable estimates of uncertainty in both the radiocarbon ages and the cal ages, and potential methods for combining datasets. This preliminary report summarizes the criteria that were discussed, but does not yet give specific recommendations for inclusion or exclusion of individual datasets.
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring samples, converted with a box diffusion model to marine mixed-layer ages, cover the period from 0–10.5 cal kyr BP. Beyond 10.5 cal kyr BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific 14C reservoir age information to provide a single global marine mixed-layer calibration from 10.5–26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the 14C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring data sets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al. (this issue).
We increase the number of remote halo tracers by using blue horizontal branch (BHB) stars out to Galactocentric distances of 130 kpc. We use SDSS EDR photometry and the VLT to detect 16 BHB stars at Galactocentric distances 70 <r < 130 kpc, and to measure their radial velocities. We find the mass of the Milky Way is M = 1.7+3.0–0.6 × 1012M⊙. When completed this survey will: (i) substantially reduce the errors in the total mass and extent of the Milky Way halo, and (ii) map the velocity space in a hitherto unexplored region of the halo.
The binary X-ray source GX 1 + 4 was observed during a balloon flight in 1986, November. The source was in a relatively high intensity state. Time analysis of the data shows that the pulsation period was 111.8 ± 1.0 s indicating that one or more episodes of spin-down occurred between 1980 and 1986. Folded pulse profiles are very broad with an indication of a notch at the peak. Evidence has been found for a correlation between hard X-ray intensity and phase of the proposed 304 day orbital period. The time averaged intensity since 1980 is an order of magnitude lower than during the 1970’s. A survey of the post 1980 data shows that several reversals of the period derivative have occurred. Spin-up at the rates typical of the 1970’s has been followed by a dramatic spin-down episode with dP/dt>2.4 × 10−7 s/s.
The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available and updated data sets from 14C measurements on tree rings, plant macrofossils, speleothems, corals, and foraminifera. The calibration curves were derived from the data using the random walk model (RWM) used to generate IntCal09 and Marine09, which has been revised to account for additional uncertainties and error structures. The new curves were ratified at the 21st International Radiocarbon conference in July 2012 and are available as Supplemental Material at www.radiocarbon.org. The database can be accessed at http://intcal.qub.ac.uk/intcal13/.
Dansgaard–Oeschger (D–O) cycles had far-reaching effects on Northern Hemisphere and tropical climate systems during the last glacial period, yet the climatic response to D–O cycles in western North America is controversial, especially prior to 55 ka. We document changes in precipitation along the western slope of the central Sierra Nevada during early Marine Oxygen Isotope Stages (MIS) 3 and 4 (55–67 ka) from a U-series dated speleothem record from McLean's Cave. The timing of our multi-proxy geochemical dataset is coeval with D–O interstadials (15–18) and stadials, including Heinrich Event 6. The McLean's Cave stalagmite indicates warmer and drier conditions during Greenland interstadials (GISs 15–18), signified by elevated δ18O, δ13C, reflectance, and trace element concentrations, and less radiogenic 87Sr/86Sr. Our record extends evidence of a strong linkage between high-latitude warming and reduced precipitation in western North America to early MIS 3 and MIS 4. This record shows that the linkage persists in diverse global climate states, and documents the nature of the climatic response in central California to Heinrich Event 6.
A systematic review/meta-analysis of literature addressing a possible association between traumatic injury and onset of multiple sclerosis was conducted. Medline, Embase, Cochrane DSR, Ovid HealthStar, CINAHL, ISI Web of Science and Scopus were searched for analytical studies from 1950 to 2011. Two investigators independently reviewed articles for inclusion, assessing their quality using the Newcastle-Ottawa Scale. Of the 13 case-control studies included, 8 were moderate quality and 5 low; of the 3 cohort studies 2 were high and 1 moderate. Meta-analysis including moderate and low quality case-control studies produced a modest but significant odds ratio: 1.41 (95% confidence interval: 1.03, 1.93). However, when low quality studies were excluded, the resulting odds ratio was non-significant. Cohort studies produced a non-significant standardized incidence ratio of 1.00 (95% confidence interval: 0.86, 1.16). These findings support the conclusion that there is no association between traumatic injury and multiple sclerosis onset; more high quality cohort studies would help to confirm this observation.
We are developing a purely commensal survey experiment for fast (<5 s) transient radio sources. Short-timescale transients are associated with the most energetic and brightest single events in the Universe. Our objective is to cover the enormous volume of transients parameter space made available by ASKAP, with an unprecedented combination of sensitivity and field of view. Fast timescale transients open new vistas on the physics of high brightness temperature emission, extreme states of matter and the physics of strong gravitational fields. In addition, the detection of extragalactic objects affords us an entirely new and extremely sensitive probe on the huge reservoir of baryons present in the IGM. We outline here our approach to the considerable challenge involved in detecting fast transients, particularly the development of hardware fast enough to dedisperse and search the ASKAP data stream at or near real-time rates. Through CRAFT, ASKAP will provide the testbed of many of the key technologies and survey modes proposed for high time resolution science with the SKA.
A computer-controlled xyz dispensing system called the Biological Architecture Tool (BAT) has been extensively tested in the creation of multilayered and three-dimensional biological objects: tissue scaffolds and plain and patterned cellular-array slides. The BAT dispensing system has proven its versatility and reliability in tissue engineering and biological experiments. The potential employments of modified versions of the xyz dispensers for in vivo minimally invasive surgery and other in vitro aspects of biological and medical research are discussed.
We have explored the effects of various processing parameters on the dielectric and
electronic integrity of sol-gel derived silicate thin films and have identified several factors that strongly affect the thin film electronic properties. We find that sol-gel dielectrics can exhibit excellent dielectric integrity: viz., low interface trap densities and fairly good insulating properties approaching those of a thermally grown SiO2 film on Si.
We have investigated the electronic properties of sol-gel derived films on silicon substrates. Our investigation involves SiO2, aluminosilicate and borosili cate oxides on silicon. Seme sol-gel oxides are excellait insulators; seme sol-gel films on silicon also exhibit quite low oxide/silicon interface trap densities. We have also subjected sol-gel films on silicon to 4 Mrad(SiO2) of radiation and have found that these structures appear to be radiation hard (very little radiation induced oxide space charge or interface trap generation). Our results strongly suggest that sol-gel processing could provide insulating films for a variety of microelectronic device applications.
Recent results indicate that certain organic molecules whose electronic structures are characterized by extended pi-molecular orbitals can exhibit significant second and third order nonlinear optical (NLO) effects . Unfortunately, this same arrangement which leads to the NLO effects, can also result in essentially one-dimensional bonding coordination. This in turn means that crystals grown from these materials do not readily form good three-dimensional optical-quality crystals, but rather tend to form needles. In addition, pure organic crystals are usually bonded by weak van der Waals forces, often resulting in poor mechanical properties. Indeed, organic impurities are frequently incorporated into these systems during crystallization resulting in poor crystallinity, spurious absorptions, and low damage thresholds. This is particularly true in the case of polymeric NLO materials, where impurities result from the polymerization steps and/or starting materials.
ABSTRACT: Silicon nitride films (a-SixN1−x:H) have been prepared by rf reactive magnetron sputtering from a silicon target in a mixture gas of Ar, N2, and H2. The effects of the presence of hydrogen gas have been related to the refractive index, deposition rate, etch rate, and the Si-H and N-H bonding in the films. Hydrogen contents were measured by a quadrupole secondary ion mass spectrometer (SIMS) using deuterium implanted samples as reference standards. The deuterium implanted samples were annealed at 900°C for various periods of time to study the diffusion behavior of deuterium and hydrogen in a Si-rich and a nearly stoichiometric silicon nitride film.
It has been observed that the low-level, pre-tunneling currents through thin gate oxides increased after the oxides had been stressed at high voltages. The number of traps inside of the oxide generated by the stress has been shown to increase as the 1/3 power of the fluence that had passed through the oxide during the stress. The increases in the low-level, pre-tunneling currents have been shown to be proportional to the number of stress generated traps in the oxide and not to the fluence during the stress. The voltage dependences of the excess low-level leakage currents were stress and measurement polarity dependent. Attempts have been made to fit the voltage dependences of the excess low-level currents to Fowler-Nordheim tunneling, Frenkel-Poole conduction or Schottky barrier lowering. The increase in the portion of the low-level, pre-tunneling current that was not dependent on stress/measurement polarity sequence was best fit using Schottky emission currents. The model that has been developed to describe the increases in the low-level currents has centered on trap-assisted currents through the oxides.
We present the changes upon isochronous annealing in the room temperature photoluminescence (PL) spectra of nearly stoichiometric silicon nitride. Samples are prepared by the 50kHz PECVD of a N2/SiH4/Helium gas mixture at 350°C. In the as-deposited films the hydrogen content was around 11% for a refractive index of 1.98. For a photoexcitation at 351 nm, the polarized PL spectrum of the as-deposited film is characterized by a main broad emission band in the visible region with a maximum at 2.55eV. A second narrow peak (FWHM = 55meV), at 3.02eV is observed. We study the evolution of the PL spectra with different isochronous anneals from 350°C to 1000°C. Even though the general shape of the PL spectra does not change, we observe an increase of quantum efficiency with maximum value upon 750°C annealing. Beyond this temperature the low energy part of the PL spectrum shows a slight increase. These variations are compared to those of the infrared absorption peaks measured on the same samples. Both the temperature dependence of the intensity of a well defined absorption peak in the Si-H stretching mode region and that of the PL features can be explained assuming that solid state chemical reactions involving hydrogen and Si-Si bonds occur in the bulk of the alloy.
It has been shown that the transient decay of the current after removal of a high voltage stressing pulse changed from an exponential RC time constant decay to a very long decay that had a 1/t time dependence[l]. During these long transients the flat-band voltages of the capacitors changed as the traps inside the oxides discharged. The discharge of both positive and negative changes near the silicon-oxide interface have been measured using QSCV measurements. In this paper the transient shifts in the flat-band voltages due to the discharging of stress generated traps in the oxide will be described.