Based on a surgical site infection (SSI) cohort at an academic center, we showed a median potentially preventable loss per non-SSI case of $17,916 in colon surgery and of $34,741 in coronary artery bypass grafting.

We report on the results of three observations of 3C 273 by ROSAT (Staubert et al. 1993).

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.

The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0–12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org.

The radiocarbon calibration curve IntCal04 extends back to 26 cal kyr B P. While several high-resolution records exist beyond this limit, these data sets exhibit discrepancies of up to several millennia. As a result, no calibration curve for the time range 26–50 cal kyr BP can be recommended as yet, but in this paper the IntCal04 working group compares the available data sets and offers a discussion of the information that they hold.

The prototype mini carbon dating system (MICADAS) at ETH Zurich has been in routine operation for almost 2 yr. Because of its simple and compact layout, setting up a radiocarbon measurement is fast and the system runs very reliably over days or even weeks without retuning. The stability of the instrument is responsible for the good performance in highest-precision measurements where results of single samples can be reproduced within less than 2‰. The measurements are described and the performance of MICADAS is demonstrated on measured data.

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).

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/.

We recently showed that the mRNA expression of genes encoding for specific nutrient sensing receptors, namely the free fatty acid receptors (FFAR) 1, 2, 3, and the hydroxycarboxylic acid receptor (HCAR) 2, undergo characteristic changes during the transition from late pregnancy to lactation in certain adipose tissues (AT) of dairy cows. We hypothesised that divergent energy intake achieved by feeding diets with either high or low portions of concentrate (60% v. 30% concentrate on a dry matter basis) will alter the mRNA expression of FFAR 1, 2, 3, as well as HCAR2 in subcutaneous (SCAT) and retroperitoneal AT (RPAT) of dairy cows in the first 3 weeks postpartum (p.p.). For this purpose, 20 multiparous German Holstein cows were allocated to either the high concentrate ration (HC, n=10) or the low concentrate ration (LC, n=10) from day 1 to 21 p.p. Serum samples and biopsies of SCAT (tail head) and RPAT (above the peritoneum) were obtained at day −21, 1 and 21 relative to parturition. The mRNA abundances were measured by quantitative PCR. The concentrations of short-chain fatty acid (SCFA) in serum were measured by gas chromatography-flame ionisation detector. The FFAR1 and FFAR2 mRNA abundance in RPAT was higher at day −21 compared to day 1. At day 21 p.p. the FFAR2 mRNA abundance was 2.5-fold higher in RPAT of the LC animals compared to the HC cows. The FFAR3 mRNA abundance tended to lower values in SCAT of the LC group at day 21. The HCAR2 mRNA abundance was neither affected by time nor by feeding in both AT. On day 21 p.p. the HC group had 1.7-fold greater serum concentrations of propionic acid and lower concentrations of acetic acid (trend: 1.2-fold lower) compared with the LC group. Positive correlations between the mRNA abundance of HCAR2 and peroxisome proliferator-activated receptor γ-2 (PPARG2) indicate a link between HCAR2 and PPARG2 in both AT. We observed an inverse regulation of FFAR2 and FFAR3 expression over time and both receptors also showed an inverse mRNA abundance as induced by different portions of concentrate. Thus, indicating divergent nutrient sensing of both receptors in AT during the transition period. We propose that the different manifestation of negative EB in both groups at day 21 after parturition affect at least FFAR2 expression in RPAT.

Van den Bergh (1964) has selected and mapped OB associations in M 31 on the basis of plates taken with the Tautenburg 52 inch Schmidt camera. The selection was done by the blinking method. The task of the present investigation is to find if there exist OB stars (single or in association) on the outermost borders of this stellar system. For this purpose we measured the brightness of all stellar objects in UBV down to the magnitude 20m.0 (B) on Tautenburg plates in a special test field (Figure 1). It includes 0.26 square degrees and its centre has a distance of 104′ = 22 kpc from the centre of M 31. This test field includes too Baade's field IV with the photoelectric standards in UBV observed by Arp (Baade and Swope, 1963) and the OB associations OB 184, OB 185 and OB 186 of Van den Bergh. The total number of stars brighter than 20m.0 (B) was 996. The stars within the associations OB 184 and OB 185 are not included in these statistics. From this number, 704 objects could be measured in all 3 colours. We found among them 23 blue objects with U–B ≤ U− ≤ −0m.25. The mean error of the brightness on the basis of 4 plates in each colour does not exceed ±0m.0.7 for stars of 19m.0 (B).

Cherubini et al. (above) question the reliability of identifying annual growth increments in olive trees, and therefore voice caution against the result of the wiggle-match of the four sections of a branch of an olive tree to the 14C calibration curve. Friedrich et al. (2006) were well aware of the problematic density structure of olive trees, and therefore assigned rather wide error margins of up to 50 per cent to the ring count. This still resulted in a late seventeenth century BC youngest date for the modelled age range of the outermost section of wood (95.4% probability). One can even remove any constraint from ring counting altogether and model the four radial sections as a simple ordered sequence, in which only the relative position is used as prior information, in other words that outer sections are younger than inner ones in a radial section.

We are interested in the stability of the localized stationary solutions of a three-component reaction-diffusion system with one activator and two inhibitors. We show that depending on control parameters, solutions in form of moving and breathing localized structures can be observed in the vicinity of the codimension-two bifurcation point. We analyze this situation performing multiple scale perturbation expansion in the vicinity of the bifurcation point and derive a set of order parameter equations, explicitly describing the dynamics of the single localized structure. Numerical simulations are carried out, showing good agreement with the analytical predictions.

Ultrafast time resolved transmission electron diffraction (TED) in a reflection geometry was used to study the cooling behavior of self-organized, well defined nanoscale germanium hut and dome clusters on Si(001). The clusters were heated in a pump-probe scheme by fs-laser pulses. The resulting transient temperature rise was then determined from the drop in diffraction intensity caused by the Debye-Waller effect. From a cooling time of τ =177 ps we estimated a strongly reduced heat transfer compared with homogeneous films of equivalent thickness.

Vital requirements for the future success of phase change media are high data transfer rates, i.e. fast processes to read, write and erase bits of information. The understanding and optimization of fast transformations is a considerable challenge since the processes only occur on a submicrometer length scale in actual bits. Hence both high temporal and spatial resolution is needed to unravel the essential details of the phase transformation. We employ a combination of fast optical measurements with microscopic analyses using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The AFM measurements exploit the fact that the phase transformation from amorphous to crystalline is accompanied by a 6% volume reduction. This enables a measurement of the vertical and lateral speed of the phase transformation. Several examples will be presented showing the information gained by this combination of techniques.

In the last decade a number of chalcogenide alloys, including ternary alloys of GeSbTe and quaternary alloys of InAgSbTe, have been identified which enable fast phase change recording. In the quest for materials with improved phase change kinetics we present two different approaches. By comparing alloys with well-defined stoichiometries the mechanisms which govern the transformation kinetics are determined. Optical and electrical measurements determine the activation energy for crystallization to 2.24 ± 0.11 eV for Ge2Sb2Te5 and to 3.71 ± 0.07 eV for Ge4Sb1Te5, respectively. It is shown that for GeSbTe-alloys with different composition the activation energy increases linearly with increasing Ge content. Power-time- reflectivity change diagrams recorded with a static tester reveal that Ge2Sb2Te5, in agreement with previous data, recrystallizes by the growth of sub critical nuclei, while Ge4Sb1Te5 grows from the crystalline rim surrounding the bit.

To speed up the search for faster materials we employ concepts of combinatorial material synthesis by producing films with a stoichiometry gradient. Then laterally resolved secondary neutral mass spectroscopy (SNMS) combined with the static tester are used to identify the composition with superior properties for phase change applications.

Light-emitting silicon nanocrystals (nc-Si) have attracted much interest due to their importance for optoelectronic devices. Electron hole recombination in a quantum confined system is generally considered as the theoretical frame explaining the photoluminescence (PL) origin. However, there is still a living debate, in particular regarding the PL decay dynamics. The decay is not single exponential and decay curves described by a stretched exponential law were systematically reported for all types of nanocrystalline silicon. The origin of this multi-exponential decay is often attributed to migration effects of the excitons between nanocrystals. In contrast to these approaches, the absence of carrier hopping has been demonstrated experimentally in porous silicon. In order to elucidate this question, specific samples were prepared, consisting in deposits made from gas phase grown silicon nanocrystals with different particle density. The nanoparticles were synthesized by laser pyrolysis of silane in a gas flow reactor, extracted as a supersonic beam, size-selected, and deposited downstream as films of variable densities by changing the deposition time. The nanoparticle number densities were determined by atomic force microscopy. Time-resolved photoluminescence measurements on these films were carried out as a function of the film density and at different PL wavelengths. The reported results showed photoluminescence properties independent of the film density. Even in the very low density film (∼4*109 particles/cm2) where nanoparticles are completely isolated from each other, the decay kinetics corresponds to a multi-exponential law. This means that exciton migration alone cannot explain the stretched exponential decay. Its origin must be linked to an intrinsic characteristic of the nc-Si particle. In this paper, the experimental results are described in more details and compared to the theoretical predictions available in the frame of the quantum confinement model. Then, the possible origins of the multi-exponential character of the decay dynamics is discussed, and the particular properties of the PL in indirect band-gap semiconductors emphasized.