1,197 research outputs found

    Infection control in burn patients: are fungal infections underestimated?

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    With great interest, I read the paper of David J. Dries about recent developments, infection control and outcomes research in the management of burn injuries [1]. I have some comments about an important, however missing, topic in the paragraphs concerning infection control

    Observations and models of star formation in the tidal features of interacting galaxies

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    Multi-color surface photometry (BVri) is presented for the tidal features in a sample of interacting galaxies. Large color variations are found between the morphological components and within the individual components. The blue colors in the primary and the tidal features are most dramatic in B-V, and not in V-i, indicating that star formation instead of metallicity or age dominates the colors. Color variations between components is larger in systems shortly after interaction begins and diminishes to a very low level in systems which are merged. Photometric models for interacting systems are presented which suggest that a weak burst of star formation in the tidal features could cause the observed color distributions. Dynamical models indicate that compression occurs during the development of tidal features causing an increase in the local density by a factor of between 1.5 and 5. Assuming this density increase can be related to the star formation rate by a Schmidt law, the density increases observed in the dynamical models may be responsible for the variations in color seen in some of the interacting systems. Limitations of the dynamical models are also discussed

    Wigner crystal vs. Friedel oscillations in the 1D Hubbard model

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    We analyze the fermion density of the one-dimensional Hubbard model using bosonization and numerical DMRG calculations. For finite systems we find a relatively sharp crossover even for moderate short range interactions into a region with 4kF4k_F density waves as a function of density. The results show that the unstable fixed point of a spin-incoherent state can dominate the physical behavior in a large region of parameter space in finite systems. The crossover may be observable in ultra cold fermionic gases in optical lattices and in finite quantum wires.Comment: 6 pages, 6 figures. Published version. The most recent file can be found at http://www.physik.uni-kl.de/eggert/papers/index.htm

    _reinterpreting the hutong

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    China is a nation growing at an alarming rate economically, socially, and structurally. It is expanding so rapidly that cities literally emerge overnight. However, Chinese architecture is caught in a very evident struggle between the past and the future. The past presents them with a long tradition of Imperial architecture in which spaces were emphasized rather than buildings. Construction consisted mainly of wood, and buildings were presented in a horizontal layout. This contrasts deeply with the steel “western” skyscrapers being constructed at a furious rate today. So, how can a culture with such a rich history of traditional building reject the principles that they have lived by for centuries? There are very few architects who have managed to successfully merge traditional Chinese strategies into a modern architectural piece. This is a challenging task because Beijing, like most Chinese cities, is still searching for its own contemporary identity. A contemporary Chinese architecture does not truly exist, and much of this is due to globalization. Evidence of this dilemma can be seen everywhere throughout China. In Beijing, the remains of an old Taoist temple now stand in a parking lot of a new mall more than twice the size of the Mall of America. Pictured is a large high rise commercial building with an awkward traditional Chinese roof placed on top. This problem is perhaps most evident in housing, which is the starting point of my thesis research. The once prominent Hutong neighborhoods that have been in families for generations are being torn down to build cheap high rise housing developments. These developments change the way people live, work and interact with others. Most of these developments take no consideration for aspects of traditional Chinese living. My intent is to analyze the traditional Chinese courtyard house and the strategies used in the building process and space design. I will then research modern architecture being constructed in China to see how it responds to these strategies. Through my research, as well as the expertise of my mentor, Wayne Drummond, I will determine what I believe to be the defining elements of traditional Chinese residential architecture. I will then pursue an answer for my initial question: what is contemporary Chinese architecture? My goal is to design a housing complex that will meet the demands of their society today while retaining the elements that defined their culture in the past

    Re-defining the Golgi complex in Plasmodium falciparum using the novel Golgi marker PfGRASP

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    Plasmodium falciparum, the causative agent of malaria, relies on a sophisticated protein secretion system for host cell invasion and transformation. Although the parasite displays a secretory pathway similar to those of all eukaryotic organisms, a classical Golgi apparatus has never been described. We identified and characterised the putative Golgi matrix protein PfGRASP, a homologue of the Golgi re-assembly stacking protein (GRASP) family. We show that PfGRASP is expressed as a 70 kDa protein throughout the asexual life cycle of the parasite. We generated PfGRASP-GFP-expressing transgenic parasites and showed that this protein is localised to a single, juxtanuclear compartment in ring-stage parasites. The PfGRASP compartment is distinct from the ER, restricted within the boundaries of the parasite and colocalises with the cis-Golgi marker ERD2. Correct subcellular localisation of this Golgi matrix protein depends on a cross-species conserved functional myristoylation motif and is insensitive to Brefeldin A. Taken together our results define the Golgi apparatus in Plasmodium and depict the morphological organisation of the organelle throughout the asexual life cycle of the parasite

    a new Pc-C boundary section

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    The widespread, terminal Ediacaran Dengying Formation (~ 551–~ 542 Ma) of South China hosts one of the most prominent negative carbonate carbon isotope excursions in Earth's history and thus bears on the correlation of the Precambrian–Cambrian boundary worldwide. The dominantly carbonate strata of the Dengying Formation are largely studied for their unique preservation of its terminal Ediacaran fauna but their geochemical context is poorly known. This study presents the first high-resolution stable isotope record (ή13C, ή18O) of calcareous siliciclastic shallow-water deposits of the Gaojiashan section (Shaanxi Province). The section includes (in ascending order) the Algal Dolomite Member, the Gaojiashan Member and the Beiwan Member of the Dengying Formation. Our data record a major ή13Ccarb negative excursion to −6 ‰ in the uppermost Gaojiashan Member which is comparable in shape and magnitude to the global Precambrian–Cambrian boundary negative ή13C excursion. Our data set is consistent with a "shallow-water anoxia" scenario which is thought to contribute to the "Cambrian explosion". The stratigraphic occurrence of Cloudina and a large negative ή13C excursion suggest that the Precambrian–Cambrian boundary is located near the top of the Gaojiashan Member and, consequently, that overlying carbonates and dolomites of the Beiwan Member are of earliest Cambrian age. Thus the Gaojiashan section may represent a new shallow-water section spanning the Precambrian–Cambrian boundary. Although bio- and chemostratigraphic data support this novel interpretation, we cannot exclude the possibility that the key excursions may represent a local perturbation indicating a restricted-basin environment

    Large-scale Star Formation Triggering in the Low-mass Arp 82 System: A Nearby Example of Galaxy Downsizing Based on UV/Optical/Mid-IR Imaging

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    As part of our Spitzer Spirals, Bridges, and Tails project to help understand the effects of galaxy interactions on star formation, we analyze GALEX ultraviolet, SARA optical, and Spitzer infrared images of the interacting galaxy pair Arp 82 (NGC 2535/6) and compare to a numerical simulation of the interaction. We investigate the multiwavelength properties of several individual star forming complexes (clumps). Using optical and UV colors, EW(Halpha), and population synthesis models we constrain the ages of the clumps and find that the median clump age is about 12 Myr. The clumps have masses ranging from a few times 10^6 to 10^9 solar masses. In general, the clumps in the tidal features have similar ages to those in the spiral region, but are less massive. The 8 micron and 24 micron luminosities are used to estimate the far-infrared luminosities and the star formation rates of the clumps. The total clump star formation rate is 2.0+/-0.8 solar masses per year, while the entire Arp 82 system is forming stars at a rate of 4.9+/-2.0 solar masses per year. We find, for the first time, stars in the HI arc to the southeast of the NGC 2535 disk. Population synthesis models indicate that all of the observed populations have young to intermediate ages. We conclude that although the gas disks and some old stars may have formed early-on, the progenitors are late-type or low surface brightness and the evolution of these galaxies was halted until the recent encounter.Comment: Accepted for publication in the AJ, 22 Figures, 5 Table

    Impact of Quantitative Feedback via High-Fidelity Airway Management Training on Success Rate in Endotracheal Intubation in Undergraduate Medical Students—A Prospective Single-Center Study

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    Endotracheal intubation is still the gold standard in airway management. For medical students and young professionals, it is often difficult to train personal skills. We tested a high-fidelity simulator with an additional quantitative feedback integration to elucidate if competence acquisition for airway management is increased by using this feedback method. In the prospective trial, all participants (n = 299; 4th-year medical students) were randomized into two groups—One had been trained on the simulator with additional quantitative feedback (n = 149) and one without (n = 150). Three simulator measurements were considered as quality criteria—The pressure on the upper front row of teeth, the correct pressure point of the laryngoscope spatula and the correct depth for the fixation of the tube. There were a total of three measurement time points—One after initial training (with additional capture of cognitive load), one during the exam, and a final during the follow-up, approximately 20 weeks after the initial training. Regarding the three quality criteria, there was only one significant difference, with an advantage for the control group with respect to the correct pressure point of the laryngoscope spatula at the time of the follow-up (p = 0.011). After the training session, the cognitive load was significantly higher in the intervention group (p = 0.008) and increased in both groups over time. The additional quantitative feedback of the airway management trainer brings no measurable advantage in training for endotracheal intubation. Due to the increased cognitive load during the training, simple airway management task training may be more efficient for the primary acquisition of essential procedural steps
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