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Neighboring tidewater glaciers often exhibit asynchronous dynamic behavior, despite relatively uniform regional atmospheric and oceanic forcings. This variability may be controlled by a combination of local factors, including glacier and fjord geometry, fjord heat content and circulation, and glacier surface melt. In order to characterize and understand contrasts in adjacent tidewater glacier and fjord dynamics, we made coincident ice-ocean-atmosphere observations at high temporal resolution (minutes to weeks) within a 10 000 km2 area near Uummannaq, Greenland. Water column velocity, temperature and salinity measurements reveal systematic differences in neighboring fjords that imply contrasting circulation patterns. The observed ocean velocity and hydrography, combined with numerical modeling, suggest that subglacial discharge plays a major role in setting fjord conditions. In addition, satellite remote sensing of seasonal ice flow speed and terminus position reveal both speedup and slow-down in response to melt, as well as differences in calving style among the neighboring glaciers. Glacier force budgets and modeling also point toward subglacial discharge as a key factor in glacier behavior. For the studied region, individual glacier and fjord geometry modulate subglacial discharge, which leads to contrasts in both fjord and glacier dynamics.
There is increasing interest in developing abattoir-based measures to assist in determining the welfare status of pigs. The primary aim of this study was to determine the most appropriate place on the slaughter line to conduct assessments of welfare-related lesions, namely apparent aggression-related skin lesions (hereafter referred to as ‘skin lesions’), loin bruising and apparent tail biting damage. The study also lent itself to an assessment of the prevalence of these lesions, and the extent to which they were linked with production variables. Finishing pigs processed at two abattoirs on the Island of Ireland (n=1950 in abattoir A, and n=1939 in abattoir B) were used. Data were collected over 6 days in each abattoir in July 2014. Lesion scoring took place at two points on the slaughter line: (1) at exsanguination (slaughter stage 1 (SS1)), and (2) following scalding and dehairing of carcasses (slaughter stage 2 (SS2)). At both points, each carcass was assigned a skin and tail lesion score ranging from 0 (lesion absent) to 3 or 4 (severe lesions), respectively. Loin bruising was recorded as present or absent. Differences in the percentage of pigs with observable lesions of each type were compared between SS1 and SS2 using McNemar/McNemar-Bowker tests. The associations between each lesion type, and both cold carcass weight and condemnations, were examined at batch level using Pearson’s correlations. Batch was defined as the group of animals with a particular farm identification code on a given day. The overall percentage of pigs with a visible skin lesion (i.e. score>0) decreased between SS1 and SS2 (P<0.001). However, the percentage of pigs with a severe skin lesion increased numerically from SS1 to SS2. The percentage of pigs with a visible tail lesion and with loin bruising also increased between SS1 and SS2 (P<0.001). There was a positive correlation between the percentage of carcasses that were partially condemned, and the percentage of pigs with skin lesions, tail lesions and loin bruising (P<0.05). In addition, as the batch-level frequency of each lesion type increased, average cold carcass weight decreased (P<0.001). These findings suggest that severe skin lesions, tail lesions and loin bruising are more visible on pig carcasses after they have been scalded and dehaired, and that this is when abattoir-based lesion scoring should take place. The high prevalence of all three lesion types, and the links with economically important production parameters, suggests that more research into identifying key risk factors is warranted.
Clostridium difficile infection (CDI) in hospitalized patients is generally attributed to the current stay, but recent studies reveal high C. difficile colonization rates on admission.
To determine the rate of colonization with toxigenic C. difficile among intensive care unit patients upon admission as well as acquired during hospitalization, and the risk of subsequent CDI.
Prospective cohort study from April 15 through July 8, 2013. Adults admitted to an intensive care unit within 48 hours of admission to the Johns Hopkins Hospital, Baltimore, Maryland, were screened for colonization with toxigenic C. difficile. The primary outcome was risk of developing CDI.
Among 542 patients, 17 (3.1%) were colonized with toxigenic C. difficile on admission and an additional 3 patients were found to be colonized during hospitalization. Both colonization with toxigenic C. difficile on admission and colonization during hospitalization were associated with an increased risk for development of CDI (relative risk, 10.29 [95% CI, 2.24–47.40], P=.003; and 15.66 [4.01–61.08], P<.001, respectively). Using multivariable analysis, colonization on admission and colonization during hospitalization were independent predictors of CDI (relative risk, 8.62 [95% CI, 1.48–50.25], P=.017; and 10.93 [1.49–80.20], P=.019, respectively), while adjusting for potential confounders.
In intensive care unit patients, colonization with toxigenic C. difficile is an independent risk factor for development of subsequent CDI. Further studies are needed to identify populations with higher toxigenic C. difficile colonization rates possibly benefiting from screening or avoidance of agents known to promote CDI.
Infect. Control Hosp. Epidemiol. 2015;36(11):1324–1329
Using an in situ load frame within a scanning electron microscope, a microstructural section on the surface of an annealed tantalum (Ta) polycrystalline specimen was mapped at successive tensile strain intervals, up to ~20% strain, using electron backscatter diffraction. A grain identification and correlation technique was developed for characterizing the evolving microstructure during loading. Presenting the correlated results builds on the reference orientation deviation (ROD) map concept where individual orientation measurements within a grain are compared with a reference orientation associated with that grain. In this case, individual orientation measurements in a deformed grain are measured relative to a reference orientation derived from the undeformed (initial) configuration rather than the current deformed configuration as has been done for previous ROD schemes. Using this technique helps reveal the evolution of crystallographic orientation gradients and development of deformation-induced substructure within grains. Although overall crystallographic texture evolved slowly during deformation, orientation spread within grains developed quickly. In some locations, misorientation relative to the original orientation of a grain exceeded 20° by 15% strain. The largest orientation changes often appeared near grain boundaries suggesting that these regions were preferred locations for the initial development of subgrains.
The Murchison Widefield Array is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array. We describe the automated radio-frequency interference detection strategy implemented for the Murchison Widefield Array, which is based on the aoflagger platform, and present 72–231 MHz radio-frequency interference statistics from 10 observing nights. Radio-frequency interference detection removes 1.1% of the data. Radio-frequency interference from digital TV is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After radio-frequency interference detection and excision, almost all data can be calibrated and imaged without further radio-frequency interference mitigation efforts, including observations within the FM and digital TV bands. The results are compared to a previously published Low-Frequency Array radio-frequency interference survey. The remote location of the Murchison Widefield Array results in a substantially cleaner radio-frequency interference environment compared to Low-Frequency Array’s radio environment, but adequate detection of radio-frequency interference is still required before data can be analysed. We include specific recommendations designed to make the Square Kilometre Array more robust to radio-frequency interference, including: the availability of sufficient computing power for radio-frequency interference detection; accounting for radio-frequency interference in the receiver design; a smooth band-pass response; and the capability of radio-frequency interference detection at high time and frequency resolution (second and kHz-scale respectively).
The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.
President Reagan's success lies not in the size of federal budget cuts but in that he has been able to make cuts at all. He has a long way to go before the New Deal is repealed or even derailed.
The Reagan budget has been viewed as revolutionary, as an unprecedented break in the tradition of modern social policy. According to Russell Baker, “… in the end even the Democrats were agreeable to the death of the New Deal, which took place this week at the Capitol.” Yet this view runs up against the fact that Ronald Reagan cut his political teeth on the New Deal, admired FDR and emulated his political style, was an ardent Democrat and an early labor organizer, and has cast his political appeal to many groups who were raised up by the New Deal to non-poor status. Is the Administration of President Reagan a repeal of the New Deal or a replay? A close look at the budget, and the political context that produced the budget, gives some partial answers.
For our purposes, the New Deal is defined as the loose set of principles and policies that has developed from the 1930s to the 1970s and formed the “mainstream” of American domestic politics. For the moment we consider the Great Society to be part of that tradition. President Reagan himself apparently does not share this assumption, viewing the New Deal as having more in common with progressivism than with the Great Society of Lyndon Johnson.
Single walled carbon nanotubes are shown to interact with a conjugated polymer in a periodic manner. Here this interaction is probed using electron microscopy, scanning tunneling microscopy optical and vibrational spectroscopy. The spectroscopic behaviour of the polymer is seen to be dramatically affected, which is attributed to conformational changes due to the effect of the nanotubes.
In this work we investigated the diffusion and clustering of supersaturated substitutional carbon 200nm thick SiGeC layers buried under a silicon cap layer of 40nm. The samples were annealed in inert (N2) or oxidizing (O2) ambient at 850°C for times ranging from 2 to 10 hours. The silicon self-interstitial (I) flux coming from the surface under oxidation enhances the C diffusion with respect to the N2 annealed samples. In the early stages of the oxidation process, carbon escape by diffusion across the layer/cap interface dominates. This phenomenon saturates after an initial period (2-4h) which depends on the C concentration. This saturation is due to the formation and growth of C containing precipitates which are promoted by the I injection and act as a sink for mobile C atoms. The competition between clustering and diffusion is discussed for two different C concentrations.
Monolayer films of poly(m-phenylenevinylene-co-2,5-dioctoxy-p-phenylenevinylene) (PmPV) supported on highly orientated pyrolytic graphite (HOPG) have been investigated using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). While there are areas of the surface covered with a featureless polymer layer, we also observe large regions with surprisingly long range order. Structural models of the polymer, as well as tunneling spectra, suggest that this ordering is derived from substrate-polymer epitaxy.
A 2 × 2 factorial experiment was conducted to determine the effects of rearing environment (indoor (In) v. outdoor (Out)) and dietary zinc oxide (ZnO) supplementation (0 (−Zn) v. 3100 (+Zn) mg/kg feed) on the response of weaned pigs to a challenge infection with enterotoxigenic Escherichia coli (ETEC). Pigs from the two rearing environments were weaned onto trial diets at 4 weeks of age, moved into conventional accommodation and infected 3 days later with 109 CFU ETEC per os. Faecal ETEC shedding was determined before and after challenge. After 7 days of ETEC infection, all pigs were euthanized for gut lactic acid bacteria (LAB)-to-coliform ratio, pH and small intestine morphological measurements. Both ZnO and outdoor rearing reduced ETEC excretion, and these effects were additive. Outdoor rearing increased small intestine and colon tissue weight. ZnO increased villus height and goblet cell number in the upper small intestine, LAB-to-coliform ratio (through reduced coliforms) in the lower small intestine and proximal colon, and improved growth performance. There were interactive effects of rearing environment and ZnO supplementation on upper small intestine villus height and daily gain, as outdoor rearing conferred advantages on these variables only with ZnO dietary supplementation. Daily gains were 233, 174, 277 and 347 (s.e.m. 27.2) g/day for the In − Zn, Out − Zn, In + Zn and Out + Zn, respectively. These results suggest different, but complementary mechanisms of intestinal health and performance in outdoor-reared pigs and those offered ZnO supplemented diets. The results indicate that the benefits of ZnO to the weaned pig extend beyond suppression of ETEC and appear mediated through altered development of the small intestine mucosa.
Gas phase processing rakes laser deposition over large areas possible but homogeneous nucleation of large atomic clusters must be avoided if films are to be produced. Clusters can be highly variable in size from a few atoms to significant fractions of a micrometer. If conditions do not allow for complete quenching of the clusters produced in the gas phase, these clusters can arrive at the substrate with sufficient energy to self sinter into homogeneous films which are substantially different from metallic films grown by thermal techniques. Using transmission electron microscopy (TEM), we have characterized the microstructure of thin metallic films deposited by laser breakdown chemical vapor deposition and identified a range of deposition conditions which can lead from powders to homogeneous polycrystalline films and mixed phase materials. Gas phase nucleation is dependent on reactant partial pressures and the gas phase quench rate which car be varied in part by adjusting the H2 content of the source gas. Manipulation of these parameters can vary powder size from about one micrometer to less than 2 nanometers. Variation of the quench rate during the deposition of polycrystalline films varies the grain size in the films. heating the substrate drastically changes the conditions under which the film is formed and as a consequence, can radically alter the microstructure of the film itself.
We have measured the energy distribution of excess charge trapped by an electron irradiated mica-glass ceramic, Macor™. Photoelectron emission as a function of incident wavelength shows two distinctly different contributions to the measured density of electron trap states. First, there is a broad continuum of binding states which extends well above the Fermi level. This results in spontaneous electron emission which depletes the excess charge in these states rapidly at room temperature and more slowly at 170K. The free decay of charge emission can be described semiclassically. Second, localized trap states appear as peaks on the continuum distribution which occur at 2.7 and 3.1 eV. These correspond to two thermionic emission peaks which occur during heating at 550K and 595K respectively. Photoemission at high intensities using the 458, 488, and 514 nm wavelengths of an argon ion laser and the 632 nm wavelength of a He-Ne laser greatly enhances the depletion of excess charge from the sample. The laser-induced emission intensity is initially high and drops rapidly, followed by a more gradual decrease. The initial intensity measures the population of electrons with binding energies less than the photon energy. The later emission is related to the repopulation of these states by the dynamic redistribution of electrons from deeper states. This behavior may lead to a model for the mechanism of electron redistribution in charged insulating materials.
Electron beam irradiation of oxides produces electron trapping states which store excess charge. Thermionic emission of this charge occurs during heating with emission peak temperatures related to binding mechanisms and energies. We present thermionic emission results which show both intrinsic and beam induced trapping states in OC-Al2O3 (sapphire) and sintered alumina. Five states have been identified with thermionic emission peaks at temperatures between -50°C and 500°C. Two states are electron beam induced and occur only for electron beam energies above fixed thresholds. These thresholds appear to correlate to with the Is core electron binding energies for oxygen and aluminum. The emission peaks from the sintered material are about 10 fold greater in intensity and slightly broadened in comparison to the single crystal. This suggests that structure plays an important role in charge trapping. Emission was also extremely sensitive to sample treatments such as annealing before electron irradiation.
Thin SiO2 films grown on silicon substrates were exposed to electron beam irradiation at energies from 100 eV to 2.5 KeV. Then, thermally stimulated exoelectron emission (TSEE) spectra were taken by heating the sample linearly to a maximum temperature of 600°C. We have compared the emission behavior from oxides grown on both n-typeand p-type, (100) and (111) silicon wafers. The TSEE spectra show emission peaks whichcan be categorized by their behavior into two groups. The β emission peaks are characteristic of emission from localized electron traps while the γ emission peaks result from the annealing of beam-induced defects. We have observed changes in the β peaks which appear to be associated with the concentration of dopants in the substrate material. In addition, we have identified a beam energy threshold near the oxygen Is binding energy for the creation of defects. This suggests that defect creation results froman electronic transition similar to electron stimulated desorption.