cssi/SciSciGPT-SciSciNet huggingface dataset:
Did the Macy’s in my mall close? Revisiting the closures of Macy’s, Sears, and JCPenney stores

The large number of closures of department stores in recent years has called into question the role of traditional brick and mortar stores in today’s retail environment. Under this context, this research investigates if the characteristics identified as significant contributors toward department store closures are consistent across time and how store closures are related to spatial accessibility. The study employs logistic regression to identify the main contributing variables toward department store closures and a 2-Step Floating Catchment Area Method is to measure the spatial accessibility of department stores. Findings reveal that early on, stores in the Western United States were the safest from closures but that effect wore off over time. Larger stores in large shopping centers were more likely to close but that effect wore off for JCPenney by 2010. Older JCPenney stores are more likely to close consistently across time, while Macy’s and Sears closures have no association with store age. The results also suggest that in general there are more stores in areas with lower accessibility but the proportion of open versus closed stores within the different ranges varies by chain, with a general trend of less closures occurring in areas with higher accessibility scores. These findings provide important information for industry practitioners and retail managers to make strategic decisions.
Dysphagia profiles after primary transoral robotic surgery or radiation for oropharyngeal cancer: A registry analysis.

OBJECTIVE To describe the physiologic swallowing impairments (MBSImP™©) associated with safety/efficiency impairments (DIGESTsafety /DIGESTefficiency grades) at 3-6 months after transoral robotic surgery (TORS) or radiation therapy (RT). STUDY DESIGN Secondary analysis of registry data. SETTING Single, academic institution. METHODS Two hundred and fifty-seven patients with HPV+ oropharynx cancer were stratified by primary treatment (75 TORS, 182 RT). Modified barium swallow studies were analyzed at baseline and 3-6 months using MBSImP scores and DIGESTsafety /DIGESTefficiency grades. DIGESTsafety /DIGESTefficiency grades and MBSImP were compared groupwise and associations between DIGESTsafety /DIGESTefficiency grades and MBSImP were explored by ordinal logistic regression. Exploratory analyses were stratified by multimodality treatment. RESULTS Neither DIGESTsafety /DIGESTefficiency differed significantly between groups at baseline or 3-6 months. Laryngeal vestibule closure was impaired more frequently in the RT group (RT: 41% vs. TORS: 27%; p = 0.02) while the TORS group had significantly more pharyngeal contraction impairment (63%; p < 0.001) compared to RT at 3-6 months. CONCLUSION The results suggest a focal injury associated with DIGESTsafety /DIGESTefficiency post-TORS in contrast to a low-level diffuse physiologic impairment associated with post-RT dysphagia.
Endophthalmitis following minimally invasive glaucoma surgery

Abstract: The prevalence of endophthalmitis after minimally invasive glaucoma surgery (MIGS) in this large 5-year series was 0.13% [0.04% – 0.30%]. All cases were associated with implantable devices. Outcomes were variable.
Fully implicit local time-stepping methods for advection-diffusion problems in mixed formulations.

This paper is concerned with numerical solution of transport problems in heterogeneous porous media. A semi-discrete continuous-in-time formulation of the linear advection-diffusion equation is obtained by using a mixed hybrid finite element method, in which the flux variable represents both the advective and diffusive flux, and the Lagrange multiplier arising from the hybridization is used for the discretization of the advective term. Based on global-in-time and nonoverlapping domain decomposition, we propose two implicit local time-stepping methods to solve the semi-discrete problem. The first method uses the time-dependent Steklov-Poincar\'e type operator and the second uses the optimized Schwarz waveform relaxation (OSWR) with Robin transmission conditions. For each method, we formulate a space-time interface problem which is solved iteratively. Each iteration involves solving the subdomain problems independently and globally in time; thus, different time steps can be used in the subdomains. The convergence of the fully discrete OSWR algorithm with nonmatching time grids is proved. Numerical results for problems with various Pecl\'et numbers and discontinuous coefficients, including a prototype for the simulation of the underground storage of nuclear waste, are presented to illustrate the performance of the proposed local time-stepping methods.
Reverse Total Shoulder Arthroplasty with Concurrent Latissimus Dorsi Tendon Transfer

Reverse total shoulder arthroplasty (rTSA) has emerged as an effective treatment option for patients with rotator cuff arthropathy resulting from irreparable rotator cuff tears. However, patients with combined loss of abduction and external rotation may still experience functional deficits after rTSA. One option to address this has been the latissimus dorsi tendon transfer (LDTT), or modified L’Episcopo procedure. The purpose of this review is to describe the role of LDTT with rTSA and to critically evaluate the evidence on whether a supplemental LDTT ultimately improves patient function. Patients with an intact rotator cuff demonstrated a significant increase in active external rotation following rTSA compared to those with a deficient rotator cuff following rTSA. Compared to their pre-operative baseline assessments, patients who undergo rTSA with LDTT report significant improvements in active external rotation. However, a randomized trial comparing rTSA patients with and without LDTT failed to demonstrate a significant difference in active external rotation or patient-reported outcomes between groups. Observational studies have shown that patients experience significant improvements in active range of motion and various patient-reported outcome measures following rTSA with latissimus dorsi tendon transfer. When directly comparing rTSA with LDTT to rTSA alone, the current literature fails to demonstrate a statistically significant difference in active external rotation or patient-reported outcomes at short-term follow-up. Further randomized controlled trials are required to fully understand the potential benefits of added tendon transfer in the rTSA patient population.
On the Effectiveness of Iterative Learning Control.

Iterative learning control (ILC) is a powerful technique for high performance tracking in the presence of modeling errors for optimal control applications. There is extensive prior work showing its empirical effectiveness in applications such as chemical reactors, industrial robots and quadcopters. However, there is little prior theoretical work that explains the effectiveness of ILC even in the presence of large modeling errors, where optimal control methods using the misspecified model (MM) often perform poorly. Our work presents such a theoretical study of the performance of both ILC and MM on Linear Quadratic Regulator (LQR) problems with unknown transition dynamics. We show that the suboptimality gap, as measured with respect to the optimal LQR controller, for ILC is lower than that for MM by higher order terms that become significant in the regime of high modeling errors. A key part of our analysis is the perturbation bounds for the discrete Ricatti equation in the finite horizon setting, where the solution is not a fixed point and requires tracking the error using recursive bounds. We back our theoretical findings with empirical experiments on a toy linear dynamical system with an approximate model, a nonlinear inverted pendulum system with misspecified mass, and a nonlinear planar quadrotor system in the presence of wind. Experiments show that ILC outperforms MM significantly, in terms of the cost of computed trajectories, when modeling errors are high.
Relationship of Fat Quality and Meat Quality Traits ofFresh Pork

Barrows and gilts (n=347) of 5 purebred lines and one commercial crossbred line were fed commercial swine diets with dried distillers grains with solubles (DDGS) inclusion at 30% of dry matter. For the final 30 days of feeding, DDGS were removed from the diet. Pigs were harvested at a minimal weight of 111.4 kg. At harvest, fat was collected from the back, belly, and jowl, and meat samples were taken from the longissimus muscle for evaluation of fat and meat quality characteristics. Jowl fat iodine values were significant predictors of back and belly fat iodine values, and increases in iodine value of the fat of the pork chop were moderately and negatively correlated with several measures of meat quality. This study demonstrates that iodine value of fat from one anatomical location (i.e., back and belly) can be predicted from iodine value of a less valuable anatomical location (i.e., jowl), and, additionally, increases in iodine value correlate negatively with predictors of meat quality.
Retroperitoneal Hematoma in Patients Undergoing Cardiac Catheterization

Objective: To retrospectively study demographic, clinical and hospital outcomes in patients who developed RPH following cardiac catheterization. Methods: Charts of patients with RPH from cardiac catheterization, between January 1, 2000 and July 30, 2005 were reviewed and compared with two control groups (Grp-I, 90 patients with local groin complications and Grp-II, 98 patients with no bleeding complications). Results: 31 cases of RPH (0.13%) were identified with 84% females. Most common presentation was hypotension (87%) and hemoglobin drop (96%). CT scan was the diagnostic modality in 93% cases. The mean body surface area in RPH group (1.77 ± .23) was significantly lower than in control group I (1.93 ± .28) and II (1.98 ± .27). The use of larger sheath size was significantly higher in the RPH group (61.3%) than control groups I (26.7%) and II (21.4%). Left groin access was significantly more in RPH group (16.1%) and control group I (17.8) than control group II (0%). The use of antiplatelets and anticoagulants were significantly higher in the RPH group. 13% of patients with RPH were treated surgically. The average hospital stay was 8.6 days, 4.5 days and 3.5 days and mortality 12.9%, 3.3% and 1% in RPH group, control group I and II respectively. Conclusion: Our study is the second largest series of RPH following cardiac catheterization and predicts female gender, large sheath size, left groin access and low body surface area as risk factors for RPH. (J Interven Cardiol 2010;23:569–574)
Bioinspired broad-spectrum micro-photocollectors improve sensitivity of image sensors in low-light environment

This paper reports an imaging system inspired from the eyes of elephantnose fish for the detection of objects in low-light environment. Our bioinspired approach realizes broad-spectrum (wavelength 350 nm ∼ 1000 nm) micro-photocollectors onto image sensors to increase their overall sensitivity by more than 3.5 times. The novel fabrication process that creates the micro-photocollectors on curved surfaces can be applied to fabricate other 3D microstructures.
Three-Dimensional Shallow Water Acoustics

Abstract : Both physical oceanographic processes and marine geological features in the areas of continental shelf and shelfbreak can cause horizontal heterogeneity in medium properties, so horizontal refraction and reflection of sound can occur and produce significant three-dimensional (3-D) sound propagation effects. The long-term goals of this project are targeted on understanding the 3-D acoustic effects, and their temporal and spatial variability, caused by the environmental factors existing commonly in the continental shelf and shelfbreak areas, such as slopes, submarine canyons, sub-bottom layers, surface waves, internal waves and shelfbreak fronts.
Conditional Simulation of Complex Geological Structures Using Multiple-Point Statistics

In many earth sciences applications, the geological objects or structures to be reproduced are curvilinear, e.g., sand channels in a clastic reservoir. Their modeling requires multiple-point statistics involving jointly three or more points at a time, much beyond the traditional two-point variogram statistics. Actual data from the field being modeled, particularly if it is subsurface, are rarely enough to allow inference of such multiple-point statistics. The approach proposed in this paper consists of borrowing the required multiple-point statistics from training images depicting the expected patterns of geological heterogeneities. Several training images can be used, reflecting different scales of variability and styles of heterogeneities. The multiple-point statistics inferred from these training image(s) are exported to the geostatistical numerical model where they are anchored to the actual data, both hard and soft, in a sequential simulation mode. The algorithm and code developed are tested for the simulation of a fluvial hydrocarbon reservoir with meandering channels. The methodology proposed appears to be simple (multiple-point statistics are scanned directly from training images), general (any type of random geometry can be considered), and fast enough to handle large 3D simulation grids.
Zidovudine, Lamivudine, and Abacavir

The history of the discovery and development of zidovudine (ZDV; or 3′-azido-3′-deoxythymidine, AZT, or Retrovir™, formerly BW A509U) is fascinating not only because it was the first Food and Drug Administration (FDA)-approved agent for the treatment of HIV, but for the unprecedented speed with which this drug moved through the new-drug approval process (Table 1). In March 1987, ZDV was approved by the FDA for use in HIV-infected individuals with a previous episode of Pneumocystis carinii pneumonia (PCP) and/or a CD4 cell count of less than 200 cells/mm3. The use of ZDV in asymptomatic or symptomatic patients with CD4 cell counts greater than 500 cells/mm3 was approved in March 1990. ZDV was initially approved as a monotherapy. Subsequently, ZDV was approved for use in combination regimens with zalcitabine and lamivudine (3TC, Epivir®). Although early studies demonstrated clinical and survival benefits of ZDV alone or in combination with other nucleoside analogs, these benefits were of limited durability because of incomplete virological suppression and the emergence of resistant HIV strains. ZDV is currently approved for the treatment of HIV infection in combination regimens with potent antiretroviral agents, including HIV protease inhibitors (PIs); nonnucleoside reverse transcriptase inhibitors (NNRTIs); and potent nucleoside reverse transcriptase inhibitors (NRTIs), such as abacavir (ABC).
PGC-1 promotes insulin resistance in liver through PPAR-α-dependent induction of TRB-3

Insulin resistance is a major hallmark in the development of type 2 diabetes, which is characterized by an impaired ability of insulin to inhibit glucose output from the liver and to promote glucose uptake in muscle. The nuclear hormone receptor coactivator PGC-1 (peroxisome proliferator-activated (PPAR)-gamma coactivator-1) has been implicated in the onset of type 2 diabetes. Hepatic PGC-1 expression is elevated in mouse models of this disease, where it promotes constitutive activation of gluconeogenesis and fatty acid oxidation through its association with the nuclear hormone receptors HNF-4 and PPAR-alpha, respectively. Here we show that PGC-1-deficient mice, generated by adenoviral delivery of PGC-1 RNA interference (RNAi) to the liver, experience fasting hypoglycemia. Hepatic insulin sensitivity was enhanced in PGC-1-deficient mice, reflecting in part the reduced expression of the mammalian tribbles homolog TRB-3, a fasting-inducible inhibitor of the serine-threonine kinase Akt/PKB (ref. 6). We show here that, in the liver, TRB-3 is a target for PPAR-alpha. Knockdown of hepatic TRB-3 expression improved glucose tolerance, whereas hepatic overexpression of TRB-3 reversed the insulin-sensitive phenotype of PGC-1-deficient mice. These results indicate a link between nuclear hormone receptor and insulin signaling pathways, and suggest a potential role for TRB-3 inhibitors in the treatment of type 2 diabetes.
Dynamic kirigami structures for integrated solar tracking

Optical tracking is often combined with conventional flat panel solar cells to maximize electrical power generation over the course of a day. However, conventional trackers are complex and often require costly and cumbersome structural components to support system weight. Here we use kirigami (the art of paper cutting) to realize novel solar cells where tracking is integral to the structure at the substrate level. Specifically, an elegant cut pattern is made in thin-film gallium arsenide solar cells, which are then stretched to produce an array of tilted surface elements which can be controlled to within ±1°. We analyze the combined optical and mechanical properties of the tracking system, and demonstrate a mechanically robust system with optical tracking efficiencies matching conventional trackers. This design suggests a pathway towards enabling new applications for solar tracking, as well as inspiring a broader range of optoelectronic and mechanical devices.
System overview and characterization of a high-temperature, high-pressure, entrained-flow, laboratory-scale gasifier

The high-temperature, high-pressure, entrained-flow, laboratory-scale gasifier at the Colorado School of Mines, including the primary systems and the supporting subsystems, is presented. The gasifier is capable of operating at temperatures and pressures up to 1650 °C and 40 bar. The heated section of the reactor column has an inner diameter of 50 mm and is 1 m long. Solid organic feedstock (e.g., coal, biomass, and solid waste) is ground into batches with particle sizes ranging from 25 to 90 μm and is delivered to the reactor at feed rates of 2–20 g/min. The maximum useful power output of the syngas is 10 kW, with a nominal power output of 1.2 kW. The initial characterization and demonstration results of the gasifier system with a coal feedstock are also reported.
Seroprevalence of Various Infectious Agents in Dogs with Suspected Acute Canine Polyradiculoneuritis

Background: Acute canine polyradiculoneuritis (ACP) is considered to be an animal model of the acute axonal form of Guillain-Barre syndrome (GBS) in humans. Various antecedent events have been associated with GBS, including bacterial or viral infection. The relationship between ACP and previous infection requires additional attention. Hypothesis: We hypothesized a relationship between ACP and serological evidence of exposure to Ehrlichia canis, Borrelia burgdorferi, Toxoplasma gondii, Neospora caninum, Campylobacter jejuni, and canine distemper virus (CDV). Animals: Eighty-eight client-owned dogs, 44 with ACP, 44 age-matched controls. Methods: Retrospective study with stored serum samples. Serum antibodies against the target organisms were measured with commercially available assays. Sera from dogs with and without ACP that were positive for T. gondii IgG by ELISA were assayed by an IgG heavy chain-specific, Western blot immunoassay. Results: Dogs with ACP (55.8%) were more likely to have T. gondii IgG serum antibody titers than dogs without ACP (11.4%). Serum antibodies from 8 affected dogs and 11 control dogs bound to T. gondii antigens with apparent molecular masses of 67, 61, 58, 45, 33, 24, 9, and 6 kDa. An antigen with an apparent molecular mass of 36 kDa was recognized by 2 dogs with ACP but none of the control dogs. Conclusions: Results of this study suggest that ACP in some dogs, like GBS in some humans, may be triggered by T. gondii and a prospective study should be performed to further evaluate this potential association.
Complex Adaptive Systems: How Informed Patient Choice Influences the Distribution of Complex Surgical Procedures

Health care in the U.S. is notoriously inefficient and ineffective, in part because the various influences affecting the different classes of participant stymie traditional top-down analysis and management techniques. This chapter presents a novel application of complex, multi-agent simulation methods to a study of how informed patient choices can influence the distribution of surgical volume for complex procedures. The simulation suggests that payer networks can have the positive effect of changing the distribution of surgical volume so that there are more highervolume providers, but can also have the negative effect of increasing the cumulative complication rates for surgeries, likely resulting from lower maximum volumes.
“New Style” Campaigning, Citizen Knowledge, and Sources of Legitimacy for State Courts: A Case Study in Texas

In this study, we explore whether perceptions of the Texas Supreme Court's legitimacy are influenced by “new style” judicial campaigns and levels of political sophistication. Using a statewide survey of Texas registered voters, we find that knowledge about the Texas judiciary and politics more generally is associated with higher levels of support for the state's supreme court. However, an embedded experiment manipulating a judicial candidate's party and issue positions does not alter individuals' perceptions of the Texas court. These results suggest that concerns over the effect of increasingly politicized judicial elections on judicial legitimacy, at least in Texas, may be exaggerated. En este estudio, exploramos si las percepciones sobre la legitimidad de la Suprema Corte de Justicia de Texas son influenciadas por el “nuevo estilo” de las campanas judiciales y los niveles de sofisticacion politica. Usando una encuesta estatal de votantes registrados en Texas, encontramos que un mayor conocimiento politico y judicial en Texas es generalmente asociado con mayores niveles de apoyo a la Suprema Corte del Estado. Sin embargo, un experimento en el que se manipulo el partido al que el candidato judicial esta afiliado y postura respecto a un asunto no altero las percepciones individuales acerca de la Corte de Texas. Estos resultados sugieren que las preocupaciones sobre los efectos de elecciones judiciales cada vez mas politizadas en la legitimidad judicial, por lo menos en Texas, pueden ser exageradas.
Improved hidden Markov model classifier for SAR images

The study reported in this paper represents a continuation of our previous work on the application of Hidden Markov models (HMMs) to the translational and rotational invariant classification of SAR targets. The traditional method of making classification decisions using an HMM does not achieve the desired objective of minimizing the number of misclassifications. We present a novel technique that minimizes the probability of misclassification error. This approach, which is an adaptation of an existing Minimum Classification Error strategy, is globally optimal. The proposed method applies basic principles of pattern recognition to reduce the expected misclassification rate by dynamically perturbing the HMM parameters using a constraint on a cross-entropy measure and distance separation between pairs of HMM models. Like the traditional implementation of an HMM, our new formulation can still be implemented using an efficient forward-backward algorithm for estimating the HMM parameters. We tested our classifier on a public mixed- target MSTAR database and compared our approach to the original HMM approach trained by using a maximum likelihood criterion. The results indicate a significant improvement over the original HMM approach. Current scores from our method are about in excess of 90% on testing data sets.
Impurity Conduction in Transmutation-Doped p -Type Germanium

The Hall coefficient and resistivity of germanium single crystals bombarded with slow neutrons were measured between 1.2 and 300\ifmmode^\circ\else\textdegree\fi{}K. Slow neutron capture and subsequent nuclear transmutation produce majority impurities, gallium atoms, and compensating impurities, arsenic and selenium atoms. $p$-type samples with a gallium concentration ranging from 8\ifmmode\times\else\texttimes\fi{}${10}^{14}$ to 5\ifmmode\times\else\texttimes\fi{}${10}^{17}$ per cc with a fixed compensation ratio of 0.40 were thus prepared and the impurity conduction was studied as a function of the average distance between the majority impurities. The effective radius $a$ of the acceptor ground-state wave function is 90.1 A according to Miller's theory of impurity conduction, whereas $a=40$ A according to Twose's theory. The latter value agrees well with the effective radius of the Kohn-Schechter acceptor wave function. The activation energy of impurity conduction changes slowly with impurity concentration from 3.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ to 5.9\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ ev and agrees well with the predictions of Miller's theory for gallium concentration below 5\ifmmode\times\else\texttimes\fi{}${10}^{15}$ per cc. Measurements on samples which contain different dislocation densities but identical impurity concentrations show that up to ${10}^{4}$ dislocations per ${\mathrm{cm}}^{2}$ do not affect impurity conduction.
Searching for the neural correlates of consciousness: clues from face recognition research.

Research has afforded irrefutable proof that mental activity is bound up with the function of the brain ... but every attempt to deduce from these facts a localization of mental processes, every endeavor to think of ideas as stored up in nerve cells and of excitations as passing along nerve-fibers has completely miscarried. The same fate would await any doctrine which attempted to recognize, let us say, the anatomical position of the system Cs-conscious mental activity-in the cortex and to localize the unconscious processes in the subcortical parts of the brain. Here there is a hiatus which at present cannot he filled, nor is it one of the tasks of psychology to fill it.
Physiological responses to the pulsation threshold paradigm. I: Pulsation threshold patterns do not reproduce physiological rate profiles of high‐pass and low‐pass noise maskers

This article compares psychophysical measures of human processing of acoustic stimuli with one neurophysiological representation (normalized discharge rate profiles) of those stimuli. Psychophysical pulsation threshold patterns (PTPs) were derived for high-pass and low-pass noise maskers. Spectral features of both maskers are clearly evident in the PTPs. However, while the representation of high-pass noise in the PTPs becomes sharper with increasing masker level, the representation of low-pass noise degenerates as masker level is increased. One assumption that has been used previously to interpret pulsation threshold data is that PTPs reflect the profile of activity in primary neural elements in response to the masking stimulus. To investigate this hypothesis, normalized-rate profiles of responses to both maskers were derived from populations of auditory-nerve fibers in cats. Normalized-rate profiles do not exhibit the same behavior as PTPs for high-pass noise maskers in that the neural representation of the band edge degenerates as sound level increases. Furthermore, the distinction between the passband and the stop band is lost in the neural rate profiles, whereas the distinction improves in the high-pass noise PTPs.
Magnetohydrodynamic stability regimes for steady state and pulsed reactors

Abstract A tokamak reactor will operate at the maximum value of β ≡ 2μ0 〈p〉/B2 that is compatible with magnetohydrodynamic (MHD) stability. This value depends on the plasma current and pressure profiles, the plasma shape and aspect ratio, and the location of nearby conducting structures. In addition, a steady state reactor will minimize its external current drive requirements and thus achieve its maximum economic benefit with a bootstrap fraction near unity, IBS/IP ≈ 1, which constrains the product of the inverse aspect ratio and the plasma poloidal β to be near unity, ϵβP ≈ 1. An inductively driven pulsed reactor has different constraints set by the steady-state Ohm's law which relates the plasma temperature and density profiles to the parallel current density. We present the results obtained during ARIES I, II/IV, and III and PULSAR reactor studies where these quantities were optimized subject to different design philosophies. The ARIES-II/IV and ARIES-III designs are both in the second stability regime, but differ in requirements in the form of the profiles at the plasma edge, and in the location of the conducting wall. The relation between these, as well as new attractive MHD regimes not utilized in the ARIES or PULSAR studies, is also discussed.
Testing procedures for spatially distributed flow models

Abstract Methods for testing, verifying, and validating predictive models of variably saturated groundwater flow are discussed. Specific procedures are introduced for measuring model complexity, assessing model consistency, and testing model validity. The discussion addresses numerical formulation, verification of internal consistency, benchmarking, groundtruth testing, performance measures, parameter estimation, hypothesis testing, and probabilistic induction. Verification of models includes tests of internal consistency and accuracy, like mass conservation and sensitivity to mesh size. Verification of codes also involves comparing results from the numerical model to analytical solutions, which are, however, limited in scope, and comparison with other numerical codes or ‘benchmarking’. These aspects are illustrated using available three-dimensional codes developed by the authors. Recognizing the diversity of spatially distributed modeling approaches, we also propose measures of model complexity and of the amount of information inherent in model predictions. One of these measures is the spatial degree of freedom, a function of material and boundary heterogeneities in the model. Another one is the quantity of information or entropy, which depends also on precision. Several aspects of ‘groundtruth’ model validation using data from laboratory and field tests are discussed. Logical inference is used to distinguish model validation from refutation. Recognizing that full validation is not possible in practice, we formulate performance criteria to define the ‘degree of validation’. Concepts and methods based on inductive calculus, Bayesian hypothesis testing, and maximum likelihood, are analyzed in some detail as alternative model validation strategies. Several examples of model testing are also discussed.
A potentially hazardous complication during central venous catheterization: lost guidewire retained in the patient

Guidewires are routinely used in the Seldinger technique during central venous catheter placement. A case in which a guidewire was unsuspectingly released and retained in a patient during the catheterization of the internal jugular vein is presented. Physicians from multiple services subsequently failed to detect the retained guidewire on several chest radiographs; however, the guidewire was incidentally discovered after a computed tomographic scan was obtained.
Noncausal effects arising from a Maxwell fluid model with negative relaxation

The physically unrealistic implications of negative relaxation in continuum mechanics is explored in the context of Stokes' first problem for Maxwell fluids. In addition, the electrodynamic analogue of negative relaxation is discussed and several lessons for students are presented. Lastly, two of Maxwell's important contributions to the physical sciences are noted.
Becoming-teacher: Encounters with the Other in teacher education

Teacher education – as currently practised – is solidly based on a developmental model of growing expertise, where novices move from error to effective practice by replicating the strategies and classroom moves of model teachers. Short timelines and limited opportunities for experience create challenges for students wishing to become teachers. Deleuze's construct of Becoming opens new perspectives on what it means for prospective teachers to explore the notion of Becoming-teacher, where learning about teaching is an encounter with ever-new situations and relationships. This chapter concludes with an invitation to teacher educators to experiment in their own practice, to do with their students, to fully explore the potentialities of Becoming-Teachers.
Effects of Hydrogen Enrichment on the Reattachment and Hysteresis of Lifted Methane Flames

The purpose of this study is to observe the effects of hydrogen enrichment on the stability of lifted, partially premixed, methane flames. Due to the relatively large burning velocity of hydrogen-air flames when compared to that of typical hydrocarbon-air flames, hydrogen enriched hydrocarbon flames are able to create stable lifted flames at higher velocities. In order to assess the impact of hydrogen enrichment, a selection of studies in lifted and attached flames were initiated. Experiments were performed that focused on the amount of hydrogen needed to reattach a stable, lifted methane jet flame above the nozzle. Although high fuel velocities strain the flame and cause it to stabilize away from the nozzle, the high burning velocity of hydrogen is clearly a dominant factor, where as the lifted position of the flame increased, the amount of hydrogen needed to reattach the flame increased at the same rate. In addition, it was observed that as the amount of hydrogen in the central jet increased, the change in flame liftoff height increased and hysteresis became more pronounced. It was found that the hysteresis regime, where the flame could either be stabilized at the nozzle or in air, shifted considerably due to the presence of a small amount of hydrogen in the fuel stream. The effects of the hydrogen enrichment, however small the amount of hydrogen compared to the overall jet velocity, was the major factor in the flame stabilization, even showing discernible effects on the flame structure.Copyright © 2013 by ASME
Modeling dendritic solidification of Al–3%Cu using cellular automaton and phase-field methods

Abstract We compared a cellular automaton (CA)–finite element (FE) model and a phase-field (PF)–FE model to simulate equiaxed dendritic growth during the solidification of cubic crystals. The equations of mass and heat transports were solved in the CA–FE model to calculate the temperature field, solute concentration, and the dendritic growth morphology. In the PF–FE model, a PF variable was used to identify solid and liquid phases and another PF variable was considered to determine the evolution of solute concentration. Application to Al–3.0 wt.% Cu alloy illustrates the capability of both CA–FE and PF–FE models in modeling multiple arbitrarily-oriented dendrites in growth of cubic crystals. Simulation results from both models showed quantitatively good agreement with the analytical model developed by Lipton–Glicksman–Kurz (LGK) in the tip growth velocity and the tip equilibrium liquid concentration at a given melt undercooling. The dendrite morphology and computational time obtained from the CA–FE model are compared to those of the PF–FE model and the distinct advantages of both methods are discussed.
Spin-label studies on rat liver and heart plasma membranes: Do probe-probe interactions interfere with the measurement of membrane properties?

The structures of purified rat liver and heart plasma membranes were studied with the 5-nitroxide stearic acid spin probe,I(12, 3). ESR spectra were recorded with a 50 gauss field sweep, and also with a new technique which “expands” the spectrum by (1) recording pairs of adjoining peaks with a smaller field sweep and (2) superposing the common peaks. The hyperfine splittings measured from the “expanded” spectra were significantly more precise than those obtained from the “unexpanded” spectra. Both procedures were used to study the effects of variousI(12,3) prove concentrations on the spectra of liver and heart membranes, as well as the effects of temperature and CaCl2 additions on the spectra of liver membranes, and revealed the following:
Origins of the term hypnotism prior to Bp5id.

Abstract Although James Braid, a Scottish physician, is generally credited with originating in 1843 the term “hypnotism,” later to become known as hypnosis in the 1880s, it was actually a Frenchman, Etienne Felix d'Henin de Cuvillers, who in an 1821 publication first applied the “hypn-” prefix to a wide array of words descriptive of the mesmeric process. Likewise, the trance induction technique of optical fixation, frequently called the Braid Effect, was known centuries prior to Braid.
Structural dynamic performance of a geostationary microwave radiometer

T synoptic addresses the on-orbit structural performance of a low-frequency microwave radiometer (LFMR) for Earth science applications. The LFMR is an instrument aboard a geostationary platform as part of the proposed program Mission to Planet Earth. The present study quantifies the ability of the LFMR structure to retain its design shape subject to a representative onboard disturbance. It includes a description of the LFMR concept, the structural model, the assumed on-orbit disturbances, and the analyses performed to quantify the antenna's resulting root mean squared (rms) surface roughness, pointing error, and defocus. These errors are measured based on the locations of the nodes of the distorted antenna relative to the ideal (error-free) antenna node positions. The electromagnetic performance of an antenna can be adversely affected by numerous factors, among which is the geometric displacement of the antenna's various structural components from their optimum positions. Minimizing the overall surface roughness, pointing error, and defocus is of extreme importance for high-precision reflector antennas such as the LFMR. Reference 1 describes in detail a sequential approach for assessing the ability of an antenna structure to retain its geometric shape subject to a dynamic disturbance.
Small-angle light scattering studies of macrophase separation in segmented polyurethane block copolymers

Abstract Quantitative small-angle light scattering (SALS) analysis is carried out on two similar segmented polyurethane block copolymers. The polyurethane prepared from toluene diisocyanate, is optically transparent, while a polyurethane prepared using the same soft segment, but with 4-4′ diphenyl methane diisocyanate, scatters light appreciably. SALS investigation of the latter sample shows clearly that the scattering arises from the presence of long-range density fluctuations. Analysis of the density fluctuations is accomplished with the Debye-Bueche theory for random two-phase systems, incorporating a correction for the effects of multiple scattering. Application of this procedure leads to a correlation length of 4200 nm; corresponding well with the structure observed in optical photo-micrographs. The occurrence of phase separation during polymerization is discussed as a possible origin for the observed macrophase structure.
On-Line Identification of Fuel Injection Timing Using Cylinder Balancing

Identification of the injection timing drift in modern diesel engine is investigated. The cylinder balancing action which is most common in modern diesel engine is utilized in locating the injection timing (injection timing with the minimum cylinder balancing correction). To find the minimum, several approaches are examined, including a parameterization based approach, sliding mode based self optimizing control and the simplex search. The proposed approaches are evaluated with experimental data from a vehicle.Copyright © 2011 by ASME
Sharpening of natural guide stars for low-order wavefront sensing using patrolling laser guide stars

A laser guide star (LGS) adaptive optics (AO) system generally requires additional tip/tilt information derived using a natural guide star (NGS), while multi-LGS systems will benefit from measurement of additional low-order wavefront modes using one or more NGS's. If we use AO sharpened NGS's, we can improve both the measurement accuracy and accessible sky fraction while also minimizing the observational overhead of faint NGS acquisition. Multi-object adaptive optics (MOAO) sharpening of NGS is possible where a good estimate of the NGS wavefront can be made, for example where tomographic wavefront information is available. We describe a new approach for high Strehl ratio sharpening, based on additional patrolling laser beacons, to eliminate generalized anisoplanatism and minimize tomography error in the NGS direction.
Milwaukee, WI, as a source of atmospheric PCBs to Lake Michigan

A field study of atmospheric PCBs in Milwaukee, WI, U.S.A. was conducted on the shore of Lake Michigan. We believe this is the first report of atmospheric PCBs in Milwaukee, although PCBs are well-known to contaminate the sediments of the Milwaukee River and Outer Harbor. Concentrations of PCBs collected during the June 2001 study are similar to concentrations in other urban-industrial areas and higher than PCBs in background air. The average ΣPCB (sum of 88 congener groups) gas-phase concentration in Milwaukee was 1.9 ng m-3 ± standard deviation 0.78 ng m-3. The average and standard deviation for the particulate-associated PCBs are 0.05 ± 0.02 ng m-3. Particulate-phase PCBs account for less than 5% of the total atmospheric concentration. PCBs in Milwaukee air are a source of PCBs to Lake Michigan. Calculated net gas exchange fluxes predicted for the Milwaukee sampling period ranged from −60 to −400 ng m-2 d-1, where net deposition is indicated by the negative sign. Calculated particle-associated PCB depo...
Perron–Frobenius type results and discrete versions of nodal domain theorems

Abstract We prove discrete versions of nodal domain theorems; in particular, an eigenvector corresponding to the s th smallest eigenvalue of a graph Laplacian has at most s nodal domains. We compare our results to those of Courant and Pleijel on nodal domains of continuous Laplacians, and to those of Fiedler on nonnegative regions of graph Laplacians.
Stereochemistry of the biosynthesis of presqualene alcohol

Abstract Current hypotheses of the biosynthesis of presqualene pyrophosphate were tested by the examination of presqualene alcohol biosynthesized from [1 R ,5 R ,9 R -1,5,9-D 3 ]farnesyl pyrophosphate and from [1- 18 O]farnesyl pyrophosphate. Nuclear magnetic resonance spectrometry showed that the octet of the two cyclopropylcarbinyl protons seen in the spectrum of protio-presqualene alcohol, centered at τ 6.35, was replaced by a broad doublet of one proton (τ, 6.23; J , 6.2 Hz), which became sharpened after deuterium decoupling and was reduced to a singlet after deuterium and proton decoupling. Also the doublet of a single olefinic proton adjacent to the cyclopropane ring, seen in the spectrum of protio-presqualene alcohol at τ 5.08 ( J , 8.5 Hz), was reduced to a broad singlet. The presqualene alcohol biosynthesized from the [1- 18 O]farnesyl pyrophosphate contained the same isotopic concentration as its precursor. The observations, taken together with previous results, are interpreted to mean that the pyrophosphate-bearing group of one farnesyl pyrophosphate molecule appears without chhnge of configuration, and without previous cleavage of the CO bond of farnesyl pyrophosphate, in presqualene pyrophosphate and that the pro- R hydrogen atom at C-1 of the second farnesyl pyrophosphate molecule appears at C-3 of the cyclopropane ring anti to the vinylic substituent. The observations support the view that presqualene pyrophosphate is not an artifact, but a true intermediate in the biosynthesis of squalene.
Skin-friction topology over a surface mounted semi-ellipsoidal wing at incidence

Flow visualization methods have been used to study the skin-friction topology of a 12:6:1 semi-ellipsoid wing at incidence intersecting a plane wall. Results were obtained for incidences from 0 to 25 deg in 5 deg increments. Major changes in the topology demarcate divisions between general ranges designated as follows: symmetry, low, intermediate, and high incidences. As a function of incidence, the topological evolution is influenced by both three-dimensional pressure gradients and transition to turbulence. A slight twist in the experimental model suggests that the topology and associated separation modes (singular vs nonsingular) are highly sensitive to slight geometric asymmetries
Effects of statins on the secretion of human serum albumin in cultured HepG2 cells

Statins reduce cholesterol biosynthesis by inhibiting HMG-CoA reductase and thereby lower total cholesterol and LDL cholesterol levels in serum, which in turn lower the incidence of cardiovascular disease (CVD). Statins are also known to modulate various cellular functions such as gene expression, cell proliferation, and programmed cell death through inhibition of downstream intermediates in cholesterol synthesis. In this study, we have investigated the possible effects of statins on the secretion of serum albumin from cultured HepG2 cells since high levels of serum albumin are associated with reduced risks for CVD and statins are effective in lowering the risk of CVD through other effects in addition to their effects on serum total cholesterol and LDL cholesterol levels, known as pleiotropic effects. Our results showed that simvastatin increased HSA secretion up to 32.3% compared to the control group. Among 3 statin analogs we tested, simvastatin exhibited the highest stimulatory effects on HSA secretion compared to the control group. Our study also showed that the increased HSA secretions from HepG2 cells by simvastatin treatments were due to the increased rate of HSA synthesis, not due to the reduced posttranslational degradation rate of HSA. Our finding suggests another added benefit of statins' treatments in preventing CVD through stimulation of HSA biosynthesis.
Twixt form and function

Uteroglobina small, water soluble homodimeric protein possessing a large interior cavityencloses a variety of endogenous and xenobiotic hydrophobic molecules. Although the structural results have mechanistic implications, the function of the protein remains speculative.
Low-Voltage Field Ionization of Gases Up to Torr-Level Pressures Using Massive Arrays of Self-Aligned Gated Nanoscale Tips

Large arrays of self-aligned gated nanoscale tips (320000 tips in 32 mm2 with average radii <;5 nm) are reported for application as gas ionizers in portable analytical instruments. The fabricated devices are capable of field ionization (FI) of gases at voltages <; 150 V even for helium with the highest ionization potential among molecules. Reliable operation of the devices was demonstrated at pressures as high as 1 Torr in He and 10 Torr in N2. FI at higher pressures was only prohibited by gas discharge rather than device failure. Ion currents as high as 0.35 nA in N2 and 0.1 nA in He were generated at a tip-to-gate bias of 200 V. Continuous operation for 104 s at 10 Torr confirmed excellent stability of the device for FI of gases. The device characteristics slowly degraded during continuous operation possibly due to particle adsorption on the tip surface. The device characteristics can be restored by operating the device as a field emitter at pressures <;10-7 Torr.