cssi/SciSciGPT-SciSciNet huggingface dataset:
Control of Pseudomonas aeruginosa AlgW protease cleavage of MucA by peptide signals and MucB

The ability of a pathogen to survive the defensive attacks of its host requires the detection of and response to perturbations in its own physiology. Activation of the extracytoplasmic stress response in the pathogen Pseudomonas aeruginosa results in higher tolerance against immune defences as well as in the production of alginate, a surface polysaccharide that also confers resistance to many host defences and antibiotic treatments. The alginate response is regulated by proteolytic cleavage of MucA, a transmembrane protein that inhibits the transcription factor AlgU, and by the periplasmic protein MucB. Here we show that specific peptides bind to the periplasmic AlgW protease and activate its cleavage of MucA. We demonstrate that tight binding of MucB to MucA strongly inhibits this cleavage. We also probe the roles of structural features of AlgW, including a key regulatory loop and its PDZ domain, in regulating substrate binding and cleavage.
Inplane Displacement of a Stressed Membrane with a Hole Measured by Holographic Interferometry

The application of holographic interferometry techniques to measure the deformation parallel to the surface of a membrane stressed parallel to its surface is described. The holographic technique used is conventional and is not insensitive to motions orthogonal to the applied stress; however, the object, a rubber membrane, is such that the principal object deformation is in the plane of the membrane and is thus revealed in the holographic image without any data reduction. The holographic results are compared with computed displacement distributions obtained from integrations of classical solutions of the stress equation. The agreement of the holographic and theoretical stress equation solution is very good.
Machining stability in turning operation when cutting with a progressively worn tool insert

Our investigation is aimed at understanding the influence of the interactions between chatter instability and tool-wear/tool-life in turning operations. An integrated experimental and analytical study has been conducted to examine changes in tool-wear with chatter instability for different cutting conditions and progressively worn cutting tools. The major tool-wear/tool-life parameters for typical grooved tools and the corresponding cutting forces in three directions are measured at varying time intervals. The variations in the wear parameters and the cutting forces are compared with the changes in stability charts of the turning operation. Explicit analytical expressions are derived for predicting the onset of chatter instability and tool-wear.
Measurements of Electrical Potentials and Ion Fluxes on Single Renal Tubules

Experimental technics are described which permit the measurements of stable electrical potential differences across the cell membrane of single renal tubule cells and across single tubules. The inside of the tubule lumen is normally found to be electrically negative to the outside, while the cell interior is found to be negative to both the peritubular fluid and the tubule lumen. Such electrical measurements, in conjunction with known concentration gradients and flux measurements of various ions across single renal tubules, permit some deductions to be made on the driving forces involved in the movement of various ion species across the luminal and peritubular cell membrane of renal tubule cells.
Bloch vector for a Raman coupled system with Stokes and anti-Stokes fields: quantum interference effects

Abstract A Bloch vector formulation of a Raman coupled model with both Stokes and anti-Stokes fields is presented. The essential feature of the model is the possible interference between different transition pathways from the ground to excited state.
Pre-harvest interventions to reduce carriage of E. coli O157 by harvest-ready feedlot cattle

Escherichia coli O157 is an important cause of food-borne illness. The primary reservoir for this organism is cattle and at present the major site of control is within abattoirs. Recent data have highlighted the importance of the pathogen load entering abattoirs on harvest-ready feedlot cattle. The likelihood for in-plant intervention failure increases as the proportion of cattle carrying E. coli O157 within a pen increases. Pre-harvest reduction of E. coli O157 colonization will require targeted intervention strategies and should reduce contamination of carcasses thereby enhancing public health. Several pre-harvest interventions show substantial promise, such as specific strains of direct-fed microbials, vaccine technology, sodium chlorate, and neomycin sulfate, whereas others such as Brown Seaweed or chlorination of water have little or no detectable benefit. Selection of validated interventions strategies will be important as efforts to control pre-harvest carriage of E. coli O157 increase.
Design and Evaluation of a Passive Alcove-Based Microfluidic Mixer

A novel passive microfluidic silicon mixer has been designed, optimized and fabricated. The architecture of the mixer consists of a simple “T” junction, made up by a 20 μm wide by 82 μm deep channel, followed by three repeats of an alcove, each with a triangular obstruction, arranged in a zigzag fashion. Numerical simulations were employed to optimize the geometry, particularly the dimensions of the alcoves, the relative orientation and the spacing between them, and the degree of intrusion associated with them. The simulation results demonstrate that chaotic flow due to recirculation within the alcoves results in transverse velocity that promotes effective fluid mixing. The microfluidic mixer with the simulation-optimized geometry was fabricated with photolithographic techniques and characterized by optical imaging, fluorescence, and Raman microscope spectroscopy. At a sample flow rate of 20 μL/s, the mixer exhibits a short mixing deadtime of ∼22 μs and a high mixing efficiency under both low and high vis...
Aggressive behavior in institutionalized elders: A theoretical framework:

This review article explores current research on aggression in institutionc ized elders and proposes a theoretical framework for use by caregivers. The relationships of brain dysfunction, past beha...
The depletion properties of silicon microstrip detectors with variable strip pitch

Abstract We have investigated the depletion properties of trapezoidal shaped silicon microstrip detectors which have variable strip pitch [1]. Four types of detectors were examined: three detectors have constant strip width and a fourth has a varying strip width. The detectors are single sided with readout performed via p + strips. The depletion properties of the devices were measured using two different methods. The first used capacitance versus voltage measurements, while the second used a 1060 nm wavelength laser coupled to a single mode fiber with a mode field diameter less than 10 μm. The small laser spot size allowed for the depletion depth to be measured in a localized area of the detector. The laser induced charge on an electrode was measured as a function of reverse bias voltage using a sensitive charge preamplifier. The depletion voltages of the detectors demonstrate a strong dependence upon the ratio of strip width to strip pitch. Moreover, these measurements show that a large value of this ration yields a lower depletion voltage and vice versa.
Photovoltaic power system reliability considerations

An example of how modern engineering and safety techniques can be used to assure the reliable and safe operation of photovoltaic power systems is presented. This particular application is for a solar cell power system demonstration project designed to provide electric power requirements for remote villages. The techniques utilized involve a definition of the power system natural and operating environment, use of design criteria and analysis techniques, an awareness of potential problems via the inherent reliability and FMEA methods, and use of fail-safe and planned spare parts engineering philosophy.
Locutionary and perlocutionary cooperation : The perlocutionary cooperative principle

Abstract This paper presents an argument for distinguishing between locutionary and perlocutionary cooperation, applying to linguistic and extra-linguistic goals, respectively. A principle governing perlocutionary cooperation is proposed and arguments for its usefulness are presented. A brief review of studies in Artificial Intelligence, Cognitive Science and Pragmatics shows some similarities between this proposal and goal-oriented approaches.
Varix of the Optic Disk

A 74-year-old woman had a saccular dilatation, presumably of the central retinal vein, on the optic nerve head. The lesion caused no symptoms, and over a four-month period showed (vidence of thrombosis and stagnation within it. The lesion caused no interference with either the arterial or venous circulation of the retina. We advised no treatment and continue to observe the patient.
Don't miss the diagnosis of sepsis!

The early detection and treatment of sepsis are the most important factors in improving the outcome of patients with this condition. However, many patients admitted to hospital experience a long delay in the diagnosis of sepsis. Furthermore, it is not uncommon for febrile patients to be sent home from the Emergency Department or the physician’s office with the diagnosis of ‘flu’ only to return hours or days later in overt septic shock. The early diagnosis of sepsis may be challenging as many of the signs and symptoms are non-specific. Clinical studies suggest that early diagnosis of sepsis requires a high index of suspicion and comprehensive clinical evaluation together with laboratory tests, including a complete blood count with differential, lactate and procalcitonin levels.
Combined impacts of highways and light rail transit on residential property values: a spatial hedonic price model for Phoenix, Arizona

Abstract This study analyzes the positive and negative relationships between housing prices and proximity to light rail and highways in Phoenix, Arizona. We hypothesize that the accessibility benefits of light rail transit (LRT) and highways accrue at nodes (stations and highway exits specifically), while disamenities emanate from rail and highway links as well as from nodes. Distance decay of amenities and disamenities is captured using multiple distance bands, and hypotheses are tested using a spatial hedonic model using generalized spatial two-stage least-squares estimation. Results show that proximity to transport nodes was associated significantly and positively with single-family detached home values. As a function of distance from highway exits and LRT stations, the distance-band coefficients form an inverted-U pattern consistent with a positive longer-range distance–decay accessibility effect minus a smaller and shorter-range distance–decay disamenity effect. The positive accessibility effect for highway exits extends farther than for LRT stations. Coefficients for the distance from highway and LRT links, however, were not significant. We also test the effect of highway design on home values and find that below-grade highways have relatively positive impacts on nearby houses compared to those at ground level or above.
Current Venues of Care and Related Costs for the Chronically Critically Ill

The chronically critically ill (CCI) patient population is characterized by a prolonged need for high cost medical interventions, a high 1-year mortality rate, and a very high demand for post acute care services. The best characterized CCI patient population is patients on prolonged mechanical ventilation (PMV). This review will focus on the current knowledge of costs and care venues for the care of this patient population. The PMV population suffers from a prolonged length of acute care hospital stay, median hospital costs 3–4 times the cost of short-term ventilator patients, frequent care venue changes during the course of illness, a small likelihood of discharge to the home environment, yet a hospital mortality that does not differ significantly from the short-term ventilated patient group. The PMV population is projected to double in size by the year 2020. Given the dramatic comparative acute care cost burden of PMV patients, the societal implications for managing both the care burden and the costs of care are staggering. Strategies to improve the efficiency in healthcare for this patient population will be essential. Limitations to the existing care models in the United States will be identified with a focus on our current research deficiencies, which limit healthcare providers and administrators in providing patient focused care for this patient population.
Ionic equilibria and decay times of neutral water clusters in moist air

Ambient air humidified by boiling water can contain high concentrations (106–107/cm3) of small hydrated ions for an hour or more after water vapor generation by boiling has ceased. Recent studies have shown that these high residual concentrations probably can be explained by the decomposition of molecular complexes of water (water clusters) generated by boiling, e.g., HX(H2O)c⇋(H+H2O)c+X− where X− may be a negative ion on an electron. Infrared absorption studies show that enormous populations of neutral water clusters like HX(H2O)c exist in moist air or steam (1012–1015/cm3). Thus the lifetimes of these populations can be estimated by electrical conductivity measurements of the ions in equilibrium with them. Typical data and decay curves are presented which show mean lifetimes for neutral clusters on the order of 15 min. It is shown that these neutral clusters are present in peaked statistical distributions and, in cloud‐chamber operation, can serve as condensation centers for atmospheric water vapor, pro...
Myeloblastic cell lines mimic some but not all aspects of human cytomegalovirus experimental latency defined in primary CD34+ cell populations.

Human cytomegalovirus (HCMV) is a significant human pathogen that achieves lifelong persistence by establishing latent infections in undifferentiated cells of the myeloid lineage, such as CD34+ hematopoietic progenitor cells. When latency is established, viral lytic gene expression is silenced in part by a cellular intrinsic defense consisting of Daxx and histone deacetylases (HDACs) because pp71, the tegument transactivator that travels to the nucleus and inactivates this defense at the start of a lytic infection in differentiated cells, remains in the cytoplasm. Because the current in vitro and ex vivo latency models have physiological and practical limitations, we evaluated two CD34+ myeloblastic cell lines, KG-1 and Kasumi-3, for their ability to establish, maintain, and reactivate HCMV experimental latent infections. Tegument protein pp71 was cytoplasmic, and immediate-early (IE) genes were silenced as in primary CD34+ cells. However, in contrast to what occurs in primary CD34+ cells ex vivo or in NT2 and THP-1 in vitro model systems, viral IE gene expression from the laboratory-adapted AD169 genome was not induced in the presence of HDAC inhibitors in either KG-1 or Kasumi-3 cells. Furthermore, while the clinical strain FIX was able to reactivate from Kasumi-3 cells, AD169 was not, and neither strain reactivated from KG-1 cells. Thus, KG-1 and Kasumi-3 experimental latent infections differ in important parameters from those in primary CD34+ cell populations. Aspects of latency illuminated through the use of these myeloblastoid cell lines should not be considered independently but integrated with results obtained in primary cell systems when paradigms for HCMV latency are proposed.
Identification of a Soybean Protein That Interacts with GAGA Element Dinucleotide Repeat DNA

Dinucleotide repeat DNA with the pattern (GA)(n)/(TC)(n), so-called GAGA elements, control gene expression in animals, and are recognized by a specific regulatory protein. Here, a yeast one-hybrid screen was used to isolate soybean (Glycine max) cDNA encoding a GAGA-binding protein (GBP) that binds to (GA)(n)/(CT)(n) DNA. Soybean GBP was dissimilar from the GAGA factor of Drosophila melanogaster. Recombinant GBP protein did not bind to dinucleotide repeat sequences other than (GA)(n)/(CT)(n). GBP bound to the promoter of the heme and chlorophyll synthesis gene Gsa1, which contains a GAGA element. Removal of that GAGA element abrogated binding of GBP to the promoter. Furthermore, insertion of the GAGA element to a nonspecific DNA conferred GBP-binding activity on that DNA. Thus, the GAGA element of the Gsa1 promoter is both necessary and sufficient for GBP binding. Gbp mRNA was expressed in leaves and was induced in symbiotic root nodules elicited by the bacterium Bradyrhizobium japonicum. In addition, Gbp transcripts were much higher in leaves of dark-treated etiolated plantlets than in those exposed to light for 24 h. Homologs of GBP were found in other dicots and in the monocot rice (Oryza sativa), as well. We suggest that interaction between GAGA elements and GBP-like proteins is a regulatory feature in plants.
ESTIMATION OF FITNESS COMPONENTS IN DROSOPHILA MELANOGASTER. II. INFLUENCE OF REDUCED TRANSMISSION FREQUENCY

Results are presented of further analyses of the significant effects of reciprocal crosses reported by Katz and Cardellino (1978) in regard to viability indices of wild-type second chromosome heterozygotes. The observed differences between reciprocal crosses can be explained by the existence of reduced transmission frequencies of the wild-type homologue from Pm/+ and Cy/+ paternal parents. Mean estimates of transmission frequencies from Pm/+ and Cy/+ males in California and Japan populations are significantly less than the Mendelian expectation of 1/2. The transmission frequencies of +i chromosomes from Pm/+i and Cy/+i males are also found to be positively correlated in the California and pooled populations, suggesting that the degree of distortion is primarily due to the +i chromosome rather than to Cy or Pm. A sufficient estimator of relative viability that is independent of distorted transmission frequencies is derived for use in the Cy/Pm technique of viability estimation.
Dendritic constructal heat exchanger with small-scale crossflows and larger-scales counterflows

This paper describes the constructal route to the conceptual design of a two-stream heat exchanger with maximal heat transfer rate per unit volume. The flow structure has multiple scales. The smallest (elemental) scale consists of parallel-plates channels the length of which matches the thermal entrance length of the small stream that flows through the channel. This feature has two advantages: it eliminates the longitudinal temperature increase (flow thermal resistance) that would occur in fully developed laminar flow, and it doubles the heat transfer coefficient associated with fully developed laminar flow. The elemental channels of hot fluid are placed in crossflow with elemental channels of cold fluid. The elemental channel pairs are assembled into sequentially larger flow structures (first construct, second construct, etc.), which have the purpose of installing (spreading) the elemental heat transfer as uniformly as possible throughout the heat exchanger volume. At length scales greater than the elemental, the streams of hot and cold fluid are arranged in counterflow. Each stream bathes the heat exchanger volume as two trees joined canopy to canopy. One tree spreads the stream throughout the volume (like a river delta), while the other tree collects the same stream (like a river basin). It is shown that the spacings of the elemental and first-construct channels can be optimized such that the overall pumping power required by the construct is minimal. The paper concludes with a discussion of the advantages of the proposed tree-like (vascularized) heat exchanger structure over the use of parallel small-scale channels with fully developed laminar flow.
Neurons as Monte Carlo Samplers: Bayesian ï¿¼Inference and Learning in Spiking Networks

We propose a spiking network model capable of performing both approximate inference and learning for any hidden Markov model. The lower layer sensory neurons detect noisy measurements of hidden world states. The higher layer neurons with recurrent connections infer a posterior distribution over world states from spike trains generated by sensory neurons. We show how such a neuronal network with synaptic plasticity can implement a form of Bayesian inference similar to Monte Carlo methods such as particle filtering. Each spike in the population of inference neurons represents a sample of a particular hidden world state. The spiking activity across the neural population approximates the posterior distribution of hidden state. The model provides a functional explanation for the Poisson-like noise commonly observed in cortical responses. Uncertainties in spike times provide the necessary variability for sampling during inference. Unlike previous models, the hidden world state is not observed by the sensory neurons, and the temporal dynamics of the hidden state is unknown. We demonstrate how such networks can sequentially learn hidden Markov models using a spike-timing dependent Hebbian learning rule and achieve power-law convergence rates.
Ultra low bit rate speech coding using an ergodic hidden Markov model

This paper presents the framework for an ultra low bit rate speech vocoder. The system is based on a recognition-synthesis paradigm in which a single ergodic hidden Markov model (EHMM) is used to capture the statistical characterizations of speech in a flexible manner capable of limiting the effects of recognition errors. Because predetermined speech units are not used, this system has the advantage of not requiring a transcription for the training data set. By incorporating a mixed excitation scheme based on an improved MELP formulation into the EHMM, additional gains in quality and speaker characterization are achieved at no cost to the bit rate.
Differentiation of transport for particulate and dissolved water chemistry load indices in rainfall–runoff from urban source area watersheds

Summary Control of coupled hydrology and pollutant transport from urban areas generally specify a runoff (or rainfall) depth for treatment. Incarnations of such coupled transport and control include the “first flush” and recent, albeit similar, “water quality volume” (WQV) concepts. For a century the first flush, a mass limited behavior, has been held as the singular transport phenomena for urban areas. In contrast, this study hypothesizes that load transport can have two classifications; mass or flow limited for pollutant phases (dissolved and particulate). Recognition, quantification, and differentiation of two limiting behaviors and phases, is less common. Differentiation is defined physically (exponential or linear); and examined statistically (logistical regression, discriminant analysis); deriving load transport rules using only calibrated hydrologic parameters. The study is supported by 28 Baton Rouge and 14 Cincinnati events; both urban, paved source areas. Once calibrated with pollutant data, statistical approaches for such rules provide promise for transport differentiation based on more economical hydrologic data. Results demonstrate load transport from source areas can be differentiated into mass or flow limited behavior. Results also indicate that within a given event, pollutant phases exhibit differing transport. With hydrologic and chemical pollutant phase transport data, calibrated event-based differentiation rules can be combined with continuous simulations in tools such as SWMM. Such a combination allows time series differentiation of load transport behavior and unit operation volumetric requirements for urban source areas.
Tryptase: potential role in airway inflammation and remodeling.

asthma is an inflammatory disease of the airways. Prominent effector cells of this inflammatory response include mast cells, eosinophils, and neutrophils, and, as such, understanding the contribution of secreted mediators from these cells to the pathophysiology of asthma has been the subject of
Enhancing Learners' Communication Skills through Synchronous Electronic Interaction and Task‐Based Instruction

ABSTRACT: Online interactive exchange offers the learner many opportunities to use the target language to negotiate both meaning and form in a social context that is crucial for second language acquisition. This paper discusses a pilot study using synchronous electronic chats combined with task-based instruction (TBI) to enhance learners' communication skills. TBI focuses on the two-way exchange of information on real-life topics. This pilot study shows that computer-mediated communication using less structure-controlled but more open-ended exchange had a significant impact on the process of language learning. Students benefited from online task-based activities because they had to access different functional skills to construct and negotiate meaning collaboratively. However, foreign language educators need to be aware that the quick cyberspace interactions impeded students from producing correct and coherent discourse, especially during learner-learner interaction. One corrective technique is to make students reexamine and revise their exchanges with guided instruction.
Long-Branch Attraction Bias and Inconsistency in Bayesian Phylogenetics

Bayesian inference (BI) of phylogenetic relationships uses the same probabilistic models of evolution as its precursor maximum likelihood (ML), so BI has generally been assumed to share ML's desirable statistical properties, such as largely unbiased inference of topology given an accurate model and increasingly reliable inferences as the amount of data increases. Here we show that BI, unlike ML, is biased in favor of topologies that group long branches together, even when the true model and prior distributions of evolutionary parameters over a group of phylogenies are known. Using experimental simulation studies and numerical and mathematical analyses, we show that this bias becomes more severe as more data are analyzed, causing BI to infer an incorrect tree as the maximum a posteriori phylogeny with asymptotically high support as sequence length approaches infinity. BI's long branch attraction bias is relatively weak when the true model is simple but becomes pronounced when sequence sites evolve heterogeneously, even when this complexity is incorporated in the model. This bias—which is apparent under both controlled simulation conditions and in analyses of empirical sequence data—also makes BI less efficient and less robust to the use of an incorrect evolutionary model than ML. Surprisingly, BI's bias is caused by one of the method's stated advantages—that it incorporates uncertainty about branch lengths by integrating over a distribution of possible values instead of estimating them from the data, as ML does. Our findings suggest that trees inferred using BI should be interpreted with caution and that ML may be a more reliable framework for modern phylogenetic analysis.
Energy-efficient tree-based indexing schemes for information retrieval in wireless data broadcast

Mobile computing can be equipped with wireless devices to allow users retrieving information from anywhere at anytime. Recently, wireless data broadcast becomes a popular data dissemination method, especially for broadcasting public information to a large number of mobile subscribers at the same time. Access Latency and Tuning Time are two main criteria to evaluate the performance of a data broadcast system. Indexing can dramatically reduce tuning time by guiding clients to turn into doze mode while waiting for the data to arrive. B+-Tree Distributed Index Scheme (BTD) is a popular index scheme for wireless data broadcast, which has been extended by many research works. Among traditional index structures, alphabetic Huffman tree is another important tree-based index technique with the advantage of taking data's access frequency into consideration. In this paper, we are trying to answer one question: can alphabetic Huffman tree replace B+-tree and provide better performance? To answer this question, we propose a novel Huffman-Tree based Distributed Index Scheme (HTD) and compare its performance with BTD based on a uniform communication environment. The performances of HTD and BTD are analyzed both theoretically and empirically. With the analysis result, we conclude that HTD outperforms BTD and can replace BTD in most existing wireless data broadcast system.
PURPOSE AND THE POWER OF COLLECTIVE AMBITION

Heard enough stories about companies falling hard and failing fast during these tough times?Douglas Ready and Emily Stecker Truelove report on companies that are purpose-driven to the point that they are strong in spite of the economic recession and are planning to do even better in the future.
Introduced species provide a novel temporal resource that facilitates native predator population growth

Non-native species are recognized as important components of change to food web structure. Non-native prey may increase native predator populations by providing an additional food source and simultaneously decrease native prey populations by outcompeting them for a limited resource. This pattern of apparent competition may be important for plants and sessile marine invertebrate suspension feeders as they often compete for space and their immobile state make them readily accessible to predators. Reported studies on apparent competition have rarely been examined in biological invasions and no study has linked seasonal patterns of native and non-native prey abundance to increasing native predator populations. Here, we evaluate the effects of non-native colonial ascidians (Diplosoma listerianum and Didemnum vexillum) on population growth of a native predator (bloodstar, Henricia sanguinolenta) and native sponges through long-term surveys of abundance, prey choice and growth experiments. We show non-native species facilitate native predator population growth by providing a novel temporal resource that prevents loss of predator biomass when its native prey species are rare. We expect that by incorporating native and non-native prey seasonal abundance patterns, ecologists will gain a more comprehensive understanding of the mechanisms underlying the effects of non-native prey species on native predator and prey population dynamics.
The Interaction of HCl With polycrystalline β-SiC: Evidence for a Site-Blocking Mechanism for HCl Inhibition of SiC CVD

Ceramic components fabricated from SiC are of considerable practical interest, with applications in heat management, turbine engines, and aerospace. Chlorine-containing precursors are attractive for chemical vapor deposition (CVD) of SiC because they are less hazardous and more economical than silane precursors. The reactivity of HCl, a by-product of these reactions, on SiC is of particular interest because it has been reported that HCl inhibits SiC CVD, but the mechanism for this inhibition has not been identified. In this work the adsorption of HCl on polycrystalline {beta}-SiC was examined with Auger Electron Spectroscopy (AES) and Temperature Programmed Desorption (TPD). HCl adsorbs readily on SiC, with an initial sticking probability of 0.1 at 300 K, and forms a strong bond, with an activation energy for desorption of 64 kcal/mol. The only product detected by TPD is HCl, which desorbs in a peak centered at 1,010 K. There are no Si- or C-containing desorption products, demonstrating that HCl does not etch SiC under TPD conditions. These results are consistent with a site-blocking mechanism for HCl inhibition of SiC CVD, but not with an etching mechanism.
In situ observations of non–equilibrium austenite formation during weld solidification of an Fe–C–Al–Mn low–alloy steel

The microstructure and properties of a welded alloy are influenced by the combined effects of solidification and subsequent solid–state transformations that occur during weld cooling. These phase transformations are further influenced by the cooling rate that the weld experiences and thus by the type of welding process that is used. In this research, microstructure development of a low–alloy steel weld was investigated under the high cooling rates produced by stationary arc welds. These welding conditions are different from the slow weld–cooling conditions, where δ–ferrite forms as the primary solidification phase. The cooling rates of the stationary welds used in this study were of the order of 10 3 K s –1 , which were high enough to induce the formation of the non–equilibrium austenite phase during solidification. This non–equilibrium mode of solidification was directly observed using an in situ time–resolved X–ray diffraction technique using synchrotron radiation, and the resulting microstructures were examined using optical microscopy.
Viewing Classroom Discipline as Negotiable Social Interaction: A Communities of Practice Perspective.

Abstract Classroom discipline is a major concern of American teachers and why many leave teaching. A conventional view of learning is so deeply interrelated with schooling in the American culture it also drives the view of discipline, especially in urban contexts where students are disproportionately failed and excluded by the mainstream educational system. The purpose of this paper is to propose a critical social practice view of learning as defined by legitimate peripheral participation (LPP), providing a communities of practice framework to guide future research that sets out to transform conventional views of learning, particularly within the context of classroom discipline.
Decreased length of stay after addition of healthcare provider in emergency department triage: a comparison between computer-simulated and real-world interventions

Objective (1) To determine the effects of adding a provider in triage on average length of stay (LOS) and proportion of patients with >6 h LOS. (2) To assess the accuracy of computer simulation in predicting the magnitude of such effects on these metrics. Methods A group-level quasi-experimental trial comparing the St. Louis Veterans Affairs Medical Center emergency department (1) before intervention, (2) after institution of provider in triage, and discrete event simulation (DES) models of similar (3) ‘before’ and (4) ‘after’ conditions. The outcome measures were daily mean LOS and percentage of patients with LOS > 6h . Results The DES-modelled intervention predicted a decrease in the %6-hour LOS from 19.0% to 13.1%, and a drop in the daily mean LOS from 249 to 200 min (p 6 h decreased from 19.9% to 14.3% (p<0.0001), with the daily mean LOS decreasing from 247 to 210 min (p<0.0001). Conclusion Physician and mid-level provider coverage at triage significantly reduced emergency department LOS in this setting. DES accurately predicted the magnitude of this effect. These results suggest further work in the generalisability of triage providers and in the utility of DES for predicting quantitative effects of process changes.
Characterization of the behavior of porous hydrogels in model osmotically‐conditioned articular cartilage systems

The evaluation of hydrogel swelling behavior is a vital step in development of new materials for biomedical applications. Phosphate-buffered saline (PBS) is the most commonly chosen swelling medium to model hydrogel behavior in articular cartilage (AC). However, the use of PBS does not fully elucidate the osmotic pressure hydrogels will face in many tissues in vivo. Thus, there is a critical need to assess the performance of hydrogels in a model system that can better reflect the native tissues for a specified application. The aim of this study was to evaluate the mechanical properties, porosity, and swelling behavior of poly(vinyl alcohol) hydrogels with a degradable poly(lactic-co-glycolic acid) (PLGA) phase in synthetic models and in ex vivo AC model systems. The controlled degradation of the PLGA phase reflected the dynamic nature of native tissues and allowed for the assessment of hydrogel swelling characteristics under fluctuating osmotic pressures. When hydrogels were implanted ex vivo into bovine AC, their swelling ratios and water contents significantly decreased. This response was matched by hydrogels immersed in a solution of PEG having an osmotic pressure matching AC. The hydrogels were further characterized over 6 weeks in PEG and in PBS, with each system having unique affects on the hydrogel swelling behavior and material properties. The results show that a PEG solution conditioned to an osmotic pressure of AC is a strong model for the effects of the osmotic environment on hydrogels and that PBS is an ineffective predictor of swelling changes in vivo.
Match Madness: Probability Matching in Prediction of the NCAA Basketball Tournament1

Every year, billions of dollars are spent gambling on the outcomes of the NCAA men's basketball tournament. This study examines how individuals make predictions for tournament pools, one of the most popular forms of betting, in which individuals must correctly predict as many games in the tournament as possible. We demonstrate that individuals predict more upsets (i.e., wins by a higher seeded team) than would be considered rational by a normative choice model, and that individuals are no better than chance at doing so. These predictions fit a pattern of probability matching, in which individuals predict upsets at a rate equal to past frequency. This pattern emerges because individuals believe the outcomes of the games are nonrandom and, therefore, predictable.
Teaching-Learning Ecologies: Mapping the Environment to Structure Through Action

Although organizational theorists have long argued that environments shape organizational structures, they have paid little attention to the processes by which the shaping occurs. This paper examines these processes by showing how environments shape teaching and learning activities, which in turn shape structure. Observational field data from structural engineering groups in three firms and hardware engineering groups in three firms revealed that the two occupations exhibited different patterns of learning episodes and different distributions of actors across those episodes, or what, following the work of Roger Barker, we call two distinct teaching-learning ecologies. After detailing the differences in the two ecologies, we show how these differences emerged from patterns of behavior that were influenced by unique sets of environmental and technological constraints. By demonstrating how actions transform environmental constraints into organizational structure, this paper indicates how research on individual learning in organizations can speak to larger concerns in organizational theory. Moreover, by adopting a synthetic and pragmatic approach to individual learning as a social activity, the paper highlights the role of teachers in workplace learning and casts doubts on the existence of a universal model of how individuals learn at work.
Creativity in GDSS: an integration of creativity, group dynamics, and problem solving theory

Organizationally critical problems are often addressed by groups. GDSS have evolved to support the problem-solving processes of groups in a wide range of decision-making tasks. However, solving particularly unstructured problems (i.e. 'wicked problems') often requires creative problem solving approaches which are best executed by individuals. In fact, many aspects of group dynamics detract from, rather than enhance, creative problem solving approaches. The paper examines the concepts of creativity, group dynamics, and problem solving in order to define how a GDSS supported environment can be made more amenable to creative problem solving. Concepts of creativity, group dynamics, and problem solving are reviewed and synthesized. Recommendations for more creative GDSS environments are given, and an existing GDSS taxonomy is reviewed in light of these recommendations. Avenues for future research are suggested. >
Is mitral valve repair superior to replacement in elderly patients

Background Mitral valve replacement is more frequently performed and perceived to be equivalent to repair in elderly patients, despite the superiority of repair in younger patients. Our objective was to compare mitral repair to replacement in elderly patients age 75 years or older. Patients younger than 75 years undergoing mitral valve surgery served as a reference population. Methods Consecutive elderly patients undergoing operation for mitral regurgitation at our institution from 1998 to 2006 were reviewed. Elderly patients (mean age, 78.0 ± 2.8 years) who underwent mitral repair (n = 70) or replacement (n = 47) were compared with cohorts of young patients (mean age, 58.9 ± 9.3 years) who underwent repair (n = 100) or replacement (n = 98) during the same period. Patient details and outcomes were compared using univariate, multivariate, and Kaplan–Meier analyses. Results Mitral replacement in elderly patients had higher mortality than repair (23.4%, 11 of 47 versus 7.1%, 5 of 70; p = 0.01) or as compared with either operation in the reference group ( p p = 0.003) or compared with either young cohort ( p = 0.02). Compared with elderly repair patients, elderly replacement patients had more cerebrovascular disease (21.3%, 10 of 47 versus 4.3%, 3 of 70; p = 0.005) and rheumatic mitral valves (21.3%, 10 of 47 versus 0%; p = 0.0001). In the young group, overall complication and mortality were no different between replacement and repair. Long-term survival favored repair over replacement in elderly patients ( p = 0.04). One elderly repair patient experienced late recurrence of persistent mitral regurgitation. Conclusions In patients age 75 years or older, mitral repair is associated with a lower risk of mortality, postoperative stroke, and prolonged intensive care unit and hospital stay compared with mitral replacement. Mitral repair can be performed in preference over replacement even in patients older than the age of 75.
Preparation of Purified KHSO5·H2O and nBu4NHSO5 from Oxone by Simple and Efficient Methods

The chemistry of various salt forms of Oxone, an environmentally friendly oxidant, has been investigated. In addition to advances in the preparation of analytically pure KHSO5·H2O and nBu4NHSO5, a soluble form of this oxidant, we have also studied some of the known oxidative chemistry that utilizes Oxone as the oxidant. Our results indicate that utilizing purified reagents makes these reactions easier to workup and amenable to large scale synthesis because the amount of salt in the reaction has been greatly reduced. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
Separation and double-bond determination on nanogram quantities of aliphatic monounsaturated alcohols, aldehydes and carboxylic acid methyl esters

On fait reagir du dimethylolisulfure puis analyse par chromatographie en phase gazeuse/spectrometrie de masse
Perturbed nuclear receptor signaling by environmental obesogens as emerging factors in the obesity crisis.

The modern world is plagued with expanding epidemics of diseases related to metabolic dysfunction. The factors that are driving obesity, diabetes, cardiovascular disease, hypertension, and dyslipidemias (collectively termed metabolic syndrome) are usually ascribed to a mismatch between the body’s homeostatic nutrient requirements and dietary excess, coupled with insufficient exercise. The environmental obesogen hypothesis proposes that exposure to a toxic chemical burden is superimposed on these conditions to initiate or exacerbate the development of obesity and its associated health consequences. Recent studies have proposed a first set of candidate obesogens (diethylstilbestrol, bisphenol A, phthalates and organotins among others) that target nuclear hormone receptor signaling pathways (sex steroid, RXR–PPARγ and GR) with relevance to adipocyte biology and the developmental origins of health and disease (DOHaD). Perturbed nuclear receptor signaling can alter adipocyte proliferation, differentiation or modulate systemic homeostatic controls, leading to long-term consequences that may be magnified if disruption occurs during sensitive periods during fetal or early childhood development.
Increased osmolality of conscious water-deprived rats supports arterial pressure and sympathetic activity via a brain action

To test the hypothesis that high osmolality acts in the brain to chronically support mean arterial pressure (MAP) and lumbar sympathetic nerve activity (LSNA), the osmolality of blood perfusing the...
Azithromycin drives alternative macrophage activation and improves recovery and tissue sparing in contusion spinal cord injury.

Background: Macrophages persist indefinitely at sites of spinal cord injury (SCI) and contribute to both pathological and reparative processes. While the alternative, anti-inflammatory (M2) phenotype is believed to promote cell protection, regeneration, and plasticity, pro-inflammatory (M1) macrophages persist after SCI and contribute to protracted cell and tissue loss. Thus, identifying non-invasive, clinically viable, pharmacological therapies for altering macrophage phenotype is a challenging, yet promising, approach for treating SCI. Azithromycin (AZM), a commonly used macrolide antibiotic, drives anti-inflammatory macrophage activation in rodent models of inflammation and in humans with cystic fibrosis. Methods: We hypothesized that AZM treatment can alter the macrophage response to SCI and reduce progressive tissue pathology. To test this hypothesis, mice (C57BL/6J, 3-month-old) received daily doses of AZM (160 mg/kg) or vehicle treatment via oral gavage for 3 days prior and up to 7 days after a moderate-severe thoracic contusion SCI (75-kdyn force injury). Fluorescent-activated cell sorting was used in combination with real-time PCR (rtPCR) to evaluate the disposition and activation status of microglia, monocytes, and neutrophils, as well as macrophage phenotype in response to AZM treatment. An open-field locomotor rating scale (Basso Mouse Scale) and gridwalk task were used to determine the effects of AZM treatment on SCI recovery. Bone marrow-derived macrophages (BMDMs) were used to determine the effect of AZM treatment on macrophage phenotype in vitro. Results: In accordance with our hypothesis, SCI mice exhibited significantly increased anti-inflammatory and decreased pro-inflammatory macrophage activation in response to AZM treatment. In addition, AZM treatment led to improved tissue sparing and recovery of gross and coordinated locomotor function. Furthermore, AZM treatment altered macrophage phenotype in vitro and lowered the neurotoxic potential of pro-inflammatory, M1 macrophages. Conclusions: Taken together, these data suggest that pharmacologically intervening with AZM can alter SCI macrophage polarization toward a beneficial phenotype that, in turn, may potentially limit secondary injury processes. Given that pro-inflammatory macrophage activation is a hallmark of many neurological pathologies and that AZM is non-invasive and clinically viable, these data highlight a novel approach for treating SCI and other maladaptive neuroinflammatory conditions.