cssi/SciSciGPT-SciSciNet huggingface dataset:
A fixed-point framework for launch vehicle ascent guidance

Recent interests in responsive launch have highlighted the need for rapid and fully automated ascent guidance planning and guidance parameter generation for launch ve­ hicles. This dissertation aims at developing the methodology and algorithms for ondemand generation of the optimal launch vehicle ascent trajectories from lift-off to achieving targeting conditions outside the atmosphere. The entire ascent trajectory from lift-off to the final target point is partitioned into two portions: the atmospheric ascent portion and the vacuum ascent portion. The two portions are seamlessly combined to­ gether via a fixed-point iteration based on the continuity condition at the junction point between the atmospheric ascent portion and the vacuum ascent portion. The previous research works on closed-loop endo-atmospheric ascent guidance shows that the classical finite difference method is well suited for fast solution of the con­ strained optimal three-dimensional ascent problem. The exploitation of certain unique features in the integration procedure between the atmospheric portion and vacuum por­ tion and the finite difference method, allows us to cast the atmospheric ascent problem into a nested fixed-point iteration problem. Therefore a novel Fixed-Point Iteration al­ gorithm is presented for solving the endo-atmospheric ascent guidance problem. Several approaches are also provided for facilitating the convergence of the fixed-point iteration. The exo-atmospheric ascent portion allows an optimal coast in between the two vacuum powered stages. The optimal coast enables more efficient usage of the propellant. The Analytical Multiple-Shooting algorithm is developed to find the optimal trajectory for this portion.
Health Locus of Control

One fundamental question facing patients, practitioners, and researchers in social science and other health fields involves exactly who or what is responsible for an individual's health. Many look to the outside world or the various social contexts surrounding the individual in locating the origins of health or disease; some focus on the personal decisions made by individuals on a day-to-day basis, and still others look to the interplay of structural considerations (i.e., life chances) and individual choices for clues relating to the various mechanisms of pathogenesis. Keywords: aging; epidemiology; health; medical sociology; medicine; socioeconomic status; sociology of health
Crystallization of Proteins: Two‐dimensional

A number of different methods can be used to produce two-dimensional crystals of proteins – planar ordered arrays one molecule in thickness. Electron crystallography of these proteins allows their structure to be determined. Keywords: electron crystallography; membrane proteins; protein crystallization; protein structure
Personal and family history of cancer and the risk of Barrett's esophagus in men

The association between Barrett's esophagus (BE) and a personal or family history of cancer other than gastroesophageal remains unknown. To evaluate the effect of personal and family history of certain cancers and cancer treatments on the risk of BE, we analyzed data from a Veterans Affairs case-control study that included 264 men with definitive BE (cases) and 1486 men without BE (controls). Patients with history of esophageal or gastric cancer were excluded. Patients underwent elective esophagogastroduodenoscopy or a study esophagogastroduodenoscopy concurrently with screening colonoscopy to determine BE status. Personal and family history of several types of cancer was obtained from self-reported questionnaires, supplemented and verified by electronic medical-record reviews. We estimated the association between personal and family history of cancer or radiation/chemotherapy, and BE. Personal history of oropharyngeal cancer (1.5% vs. 0.4%) or prostate cancer (7.2% vs. 4.4%) was more frequently present in cases than controls. The association between BE and prostate cancer persisted in multivariable analyses (adjusted odds ratio 1.90; 95% confidence interval 1.07-3.38, P = 0.028) while that with oropharyngeal cancer (adjusted odds ratio 3.63; 95% confidence interval 0.92-14.29, P = 0.066) was attenuated after adjusting for retained covariates of age, race, gastroesophageal reflux disease, hiatal hernia, and proton pump inhibitor use. Within the subset of patients with cancer, prior treatment with radiation or chemotherapy was not associated with BE. There were no significant differences between cases and controls in the proportions of subjects with several specific malignancies in first- or second-degree relatives. In conclusion, the risk of BE in men may be elevated with prior personal history of oropharyngeal or prostate cancer. However, prior cancer treatments and family history of cancer were not associated with increased risk of BE. Further studies are needed to elucidate if there is a causative relationship or shared risk factors between prostate cancer and BE.
Context and ontology in understanding of dialogs

We present a model of NLP in which ontology and context are directly included in a grammar. The model is based on the concept of {\em construction}, consisting of a set of features of form, a set of semantic and pragmatic conditions describing its application context, and a description of its meaning. In this model ontology is embedded into the grammar; e.g. the hierarchy of {\it np} constructions is based on the corresponding ontology. Ontology is also used in defining contextual parameters; e.g. $\left[ current\_question \ time(\_) \right] $. A parser based on this model allowed us to build a set of dialog understanding systems that include an on-line calendar, a banking machine, and an insurance quote system. The proposed approach is an alternative to the standard "pipeline" design of morphology-syntax-semantics-pragmatics; the account of meaning conforms to our intuitions about compositionality, but there is no homomorphism from syntax to semantics.
INFLUENCE OF POWER ULTRASOUND ON OXIDATIVE RANCIDITY OF POTATO CHIPS

Removal of some lipids on the surface, or from a layer adjacent to the surface of potato chips, was investigated as a means to extend the oxidative stability. Classic potato chips purchased from a local grocery store were subjected to sonication in n-hexane at room temperature for 1 min. Oxidative stability of the potato chips with and without surface lipids removed was examined by accelerated oxidative stability testing, where samples were stored in an environmental chamber set at 35C. The oxidative stability index was measured with an oxidative stability instrument. As compared with the nonsonicated potato chips, the oxidative stability of sonicated samples was improved by 25, 14, 11, 6 and 21% during the 0, 2, 4, 6 and 8th week of storage, respectively. In average, sonication resulted in 15% improvement of the oxidative stability of potato chips during the 8 weeks of storage at 35C. Thus, it was observed that removing some lipids from the surface of the potato chips by power ultrasound improved the storage oxidative stability. PRACTICAL APPLICATIONS Sonication treatment used in this study was capable of reducing peanut lipid rancidity. This research demonstrated the potential of power ultrasound to remove lipids from the potato chips and improve oxidative stability during storage. This research indicated that sonication could provide an alternative for improving the oxidative stability and eventually shelf life and quality of potato chips.
Ion recombination correction factors (Pion) for Varian TrueBeam high-dose-rate therapy beams

Ion recombination is approximately corrected for in the Task Group 51 protocol by Pion, which is calculated by a two-voltage measurement. This measurement approach may be a poor estimate of the true recombination, particularly if Pion is large (greater than 1.05). Concern exists that Pion in high-dose-per-pulse beams, such as flattening filter free (FFF) beams, may be unacceptably high, rendering the two-voltage measurement technique inappropriate. Therefore, Pion was measured for flattened beams of 6, 10, 15, and 18 MV and for FFF beams of 6 and 10 MV. The values for the FFF beams were verified with 1/V versus 1/Q curves (Jaffe plots). Pion was also measured for electron beams of 6, 12, 16, 18, and 20 MeV on a traditional accelerator, as well as on the high-dose-rate Varian TrueBeam accelerator. The measurements were made at a range of depths and with PTW, NEL, and Exradin Farmer-type chambers. Consistent with the increased dose per pulse, Pion was higher for FFF beams than for flattening filter beams. However, for all beams, measurement locations, and chambers examined, Pion never exceeded 1.018. Additionally, Pion was always within 0.3% of the recombination calculated from the Jaffe plots. We conclude that ion recombination can be adequately accounted for in high-dose-rate FFF beams using Pion determined with the standard two-voltage technique.
Structural features of a 3' splice site in influenza a

Influenza A is an RNA virus with a genome of eight negative sense segments. Segment 7 mRNA contains a 3′ splice site for alternative splicing to encode the essential M2 protein. On the basis of sequence alignment and chemical mapping experiments, the secondary structure surrounding the 3′ splice site has an internal loop, adenine bulge, and hairpin loop when it is in the hairpin conformation that exposes the 3′ splice site. We report structural features of a three-dimensional model of the hairpin derived from nuclear magnetic resonance spectra and simulated annealing with restrained molecular dynamics. Additional insight was provided by modeling based on 1H chemical shifts. The internal loop containing the 3′ splice site has a dynamic guanosine and a stable imino (cis Watson–Crick/Watson–Crick) GA pair. The adenine bulge also appears to be dynamic with the A either stacked in the stem or forming a base triple with a Watson–Crick GC pair. The hairpin loop is a GAAA tetraloop closed by an AC pair.
The luminosity functions of the 1969 Perseid and Orionid meteor showers

Observations of the 1969 Perseid and Orionid meteor showers are presented and used to derive luminosity functions for the 288 Perseids and 56 Orionids detected. Visual counts were performed under very good to excellent seeing conditions at the times of peak activities, and the brightnesses of the meteors were estimated to the nearest magnitude by comparison with the magnitudes of known objects. Maximum likelihood estimates of the power law index of the luminosity function of 1.56 + or - 0.06 for the Perseids and of 1.85 + or - 0.1 for the Orionids are obtained which are lower than the values found by other investigators. Under the assumption that the luminosity of visual meteors is proportional to their mass, the luminosity function power law may also be used to characterize the mass function.
Postmenopausal Hormones and Glycemic Effects

TO THE EDITOR: We read with interest Kanaya and colleagues’ report that combination hormone replacement therapy (HRT) reduced the incidence of type 2 diabetes mellitus by 35% (6.2% vs. 9.5% [P 0.006]; number needed to treat for benefit [NNTB] for 4 years 30) among postmenopausal women with coronary disease (1). We wonder whether the authors can comment on the possible contribution of exercise to the observed effect. Kanaya and colleagues analyzed several potential mediators of treatment effect on diabetes incidence, including waist circumference, body mass index (BMI), change in weight, smoking, markers of the metabolic syndrome, and certain cardiac medications, but they did not mention exercise. In the Diabetes Prevention Program, a randomized, controlled trial (2), a lifestyle intervention designed to achieve goals of a 7% reduction in body weight and 150 minutes of physical activity per week was more effective than metformin or placebo in preventing diabetes (NNTB for 3 years 7). The remarkable effect of the lifestyle intervention observed in the Diabetes Prevention Program and the fact that Kanaya and colleagues reported baseline levels of physical activity make us wonder whether Kanaya and colleagues have follow-up data regarding physical activity. As the authors noted, the mechanism by which combination HRT might prevent diabetes is unknown. Is it possible that a change in exercise amount in persons taking estrogen compared with controls could explain the results?
A Neurocomputing Approach for Monitoring Plinian Volcanic Eruptions Using Infrasound

Abstract Plinian volcanic eruptions can inject a substantial amount of volcanic ash and gas into the stratosphere, which can present a severe hazard to commercial air traffic. A hazardous volcanic ash eruption was reported on April 14, 2010, and London's aviation authority issued an alert that an ash plume was moving from an eruption in Iceland towards northwestern Europe. This eruption resulted in the closure of large areas of European airspace. Large plinian volcanic eruptions radiate infrasonic signals that can be detected by a global infrasound array network. To reduce potential hazards for commercial aviation from volcanic ash, these infrasound sensor arrays have been used to detect infrasonic signals released by sustained volcanic eruptions that can inject ash into the stratosphere at aircraft's cruising altitudes, typically in the order of 10 km. A system that is capable of near, real-time eruption detection and discrimination of plinian eruptions from other natural phenomena that can produce infrasound with overlapping spectral content (0.01 to 0.1 Hz) is highly desirable to provide ash-monitoring for commercial aviation. In this initial study, cepstral features are extracted from plinian volcanic eruption and mountain associated wave infrasound signals. These feature vectors are then used to train and test a two-module neural network classifier. One module is dedicated to classifying plinian volcano eruptions, the other mountain associated waves. Using an independent validation dataset, the classifier's correct classification rate is 91.5%.
Ecdysteroid titres and integument changes in superparasitized puparia of Anastrepha suspensa (Diptera: Tephritidae)

Larval-pupal apolysis of Anastrepha suspensa is inhibited when superparasitized (up to 7 parasites/host) by the solitary endoparasite Biosteres longicaudatus. Ecdysone 20-monooxygenase activity was similar in superparasitized hosts and controls and could not explain the significantly (P < 0.05) high ecdysteroid titres, especially in 36–48-h-old hosts. In the control, synthesis of the outer and inner epicuticules coincided with a significantly (P < 0.01) low ecdysteroid titre. Presumably, an inhibitory effect of high ecdysteroid titres and the abnormal proliferation of microvilli at the cuticle-epidermis interface led to the inability of superparasitized hosts to synthesize new cuticle. Moreover, the migration and exocytosis of vesicles observed at the cell apices in the control did not occur in superparasitized individuals which did not apolyse. Viral particles, presumably of the rhabdovirus type (300 × 80 nM) proliferated in large vesicles bordering the basement membrane of epidermal cells in superparasitized puparia. These viruses may have affected the migration of vesicles to the cell apices and the activation of the moulting fluid. Pox virus-like particles (240 nM in diameter) were also observed in haemocytes adjacent to the epidermal cells. Superparasitized A. suspensa were unable to initiate larval-pupal apolysis due presumably, to: (a) their inability to secrete moulting gel and (b) high ecdysteroid titres that may also have inhibited the synthesis of a new cuticle.
High-resolution sea ice in long-term global ocean GCM integrations

Abstract The resolution of the sea-ice component of a coarse-resolution global ocean general circulation model (GCM) has been enhanced to about 22 km in the Southern Ocean. The ocean GCM is designed for long-term integrations suitable for investigations of the deep-ocean equilibrium response to changes in southern hemisphere high-latitude processes. The space and time scales of the high-resolution sea-ice component are commensurate with those of the resolution of satellite passive-microwave sea-ice data. This provides the opportunity for a rigorous evaluation of simulated sea-ice characteristics. It is found that the satellite-derived continuous high ice concentration of the interior winter ice pack can only be captured when vertical oceanic mixing is modified in a way that less local, intermittent convection occurs. Furthermore, the width and the variability of the coastal polynyas around the Antarctic continent and its ice shelves are best captured when some form of ice-shelf melting is accounted for. The width of the wintertime ice edge is reasonably reproduced, while its variability remains underestimated, closely following the coarse-grid pattern of the ocean model due to its high dependence on ocean temperature. Additional variability besides daily winds, e.g. in form of idealized tidal currents, improves the temporal and spatial ice-edge variability, while leads in the interior ice pack become more abundant, more in line with the fine-scale satellite-derived texture. The coast- or ice-shelf line is described on the fine grid based on satellite passive-microwave data. This method requires parts of a coarse coastal ocean grid cell to be covered by an inert layer of “fast ice” or “ice shelf”. Reasonable long-term global deep-ocean properties can only be achieved when these areas are not inert, i.e. are exposed to heat flux and ice growth, or when the vertical mixing parameterization allows for excessive open-ocean convection. The model area exposed to cold high-latitude atmospheric conditions thus being most decisive for a realistic representation of the long-term deep-ocean properties, suggests that high-latitude coastlines are definitely in need of being represented at high resolution, including ice sheets and their effects on the heat and freshwater flux for the ocean.
Human Lipooligosaccharide IGG That Prevents Endemic Meningococcal Disease Recognizes an Internal Lacto-N-neotetraose Structure

Antibodies that initiate complement-mediated killing of Neisseria meningitidis as they enter the bloodstream from the oropharynx protect against disseminated disease. Human IgGs that bind the neisserial L7 lipooligosaccharide (LOS) are bactericidal for L3,7 and L2,4 meningococci in the presence of human complement. These strains share a lacto-N-neotetraose (nLc4) LOS α chain. We used a set of mutants that have successive saccharide deletions from the nLc4 α chain to characterize further the binding and bactericidal activity of nLc4 LOS IgG. We found that the nLc4 α chain conforms at least four different antigens. We separately purified IgG that required the nLc4 (non-reducing) terminal galactose (Gal) for binding and IgG that bound the truncated nLc3 α chain that lacks this Gal residue. IgG that bound the internal nLc3 α chain killed both L3,7 and L2,4 strains, whereas IgG that required the nLc4 terminal Gal residue for binding killed L2,4 stains but not L3,7 strains. These results show that the diversity of LOS antibodies in human serum is as much a function of the conformation of multiple antigens by a single glycoform as of the production of multiple glycoforms. Differences in sensitivity to killing by human nLc4 LOS IgG may account for the fact that fully two-thirds of endemic group B meningococcal disease in infants and children is caused by L3,7 strains, but only 20% is caused by L2,4 stains.
Three-dimensional simulations of convection in layers with tilted rotation vectors

Three-dimensional and time-dependent numerical simulations of thermal convection are carried out for rotating layers in which the rotation vector is tilted from the vertical to represent various latitudes. The vertical component of the rotation vector produces narrow convection cells and a reduced heat flux. As this vertical component of the rotation vector diminishes in the lower latitudes, the vertical heat flux increases. The horizontal component of the rotation vector produces striking changes in the convective motions. It elongates the convection cells in a north–south direction. It also tends to turn upward motions to the west and downward motions to the east in a manner that produces a large-scale circulation. This circulation is directed to the west and towards the poles in the upper half of the layer and to the east and towards the equator in the bottom half. Since the layer is warmer on the bottom this circulation also carries an equatorward flux of heat. When the rotation vector is tilted from the vertical, angular momentum is always transported downwards and toward the equator. For rapidly rotating layers, the pressure field changes in a manner that tends to balance the Coriolis force on vertical motions. This results in an increase in the vertical heat flux as the rotation rate increases through a limited range of rotation rates.
Direct imaging of RecA nucleation and growth on single molecules of SSB-coated ssDNA

Escherichia coli RecA is the defining member of a ubiquitous class of DNA strand-exchange proteins that are essential for homologous recombination, a pathway that maintains genomic integrity by repairing broken DNA. To function, filaments of RecA must nucleate and grow on single-stranded DNA (ssDNA) in direct competition with ssDNA-binding protein (SSB), which rapidly binds and continuously sequesters ssDNA, kinetically blocking RecA assembly. This dynamic self-assembly on a DNA lattice, in competition with another protein, is unique for the RecA family compared to other filament-forming proteins such as actin and tubulin. The complexity of this process has hindered our understanding of RecA filament assembly because ensemble measurements cannot reliably distinguish between the nucleation and growth phases, despite extensive and diverse attempts. Previous single-molecule assays have measured the nucleation and growth of RecA--and its eukaryotic homologue RAD51--on naked double-stranded DNA and ssDNA; however, the template for RecA self-assembly in vivo is SSB-coated ssDNA. Using single-molecule microscopy, here we directly visualize RecA filament assembly on single molecules of SSB-coated ssDNA, simultaneously measuring nucleation and growth. We establish that a dimer of RecA is required for nucleation, followed by growth of the filament through monomer addition, consistent with the finding that nucleation, but not growth, is modulated by nucleotide and magnesium ion cofactors. Filament growth is bidirectional, albeit faster in the 5'→3' direction. Both nucleation and growth are repressed at physiological conditions, highlighting the essential role of recombination mediators in potentiating assembly in vivo. We define a two-step kinetic mechanism in which RecA nucleates on transiently exposed ssDNA during SSB sliding and/or partial dissociation (DNA unwrapping) and then the RecA filament grows. We further demonstrate that the recombination mediator protein pair, RecOR (RecO and RecR), accelerates both RecA nucleation and filament growth, and that the introduction of RecF further stimulates RecA nucleation.
The Effect of Soil Thermal Conductivity Parameterization on Surface Energy Fluxes and Temperatures

Abstract The sensitivity of sensible and latent heat fluxes and surface temperatures to the parameterization of the soil thermal conductivity is demonstrated using a soil vegetation atmosphere transfer scheme (SVATS) applied to intensive field campaigns (IFCs) 3 and 4 of the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE). In particular, the commonly used function for soil thermal conductivity presented by M. C. McCumber and R. A. Pielke results in overestimation during wet periods and underestimation during dry periods, as confirmed with thermal conductivity data collected at the FIFE site. The ground heat flux errors affect all components of the energy balance, but are partitioned primarily into the sensible heat flux and surface temperatures in the daytime. At nighttime, errors in the net radiation also become significant in relative terms, although all fluxes are small. In addition, this method erroneously enhances the spatial variability of fluxes assoc...
CCD-based detector for crystallographic applications using laboratory x-ray sources

We describe a modular detector designed primarily for macro-molecular x-ray crystallography experiments which use a rotating-anode x-ray source. The module consists of a fiber optic demagnifying taper with a phosphor x-ray converter deposited on the large end of the taper and a CCD bonded to the small end. Two or more modules can be used together to increase the total detector area. The detector components are chosen to optimize data-collection efficiency while keeping the overall cost relatively low and the reliability high. Performance measurements for a prototype detector of this design are presented.
Pathfinder and Other Tools for Analyzing Signal Transduction Networks

Many electronic design tools are, at their core, tools for analyzing interacting networks of components in which there is a definite causal sense of direction in each interaction: outputs affect inputs, but not vice versa. Simplifying or restricting a network of protein interactions so that this kind of directedness holds makes the same category of software tools applicable. In signal transduction cascades the direction is usually given by "kinase phosphorylates substrate." This paper examines a few kinds of directed network analysis tools in the context of signal transduction.
A signal-switch hypothesis for cross-regulation of cytokine and TLR signalling pathways

The importance of immunoreceptor tyrosine-based activation motif (ITAM)-coupled receptors in modulating signalling pathways downstream of other types of receptor is well established, but the mechanisms underlying this modulation are not known. Recent data suggest that calcium-dependent signalling downstream of ITAM-coupled receptors regulates the amplitude and functional outcomes of cytokine and TLR signalling. In this Opinion article, I describe a model whereby the intensity of ITAM-dependent signalling and the balance of calcium signals relative to other ITAM-mediated signalling pathways determines whether cellular responses to cytokines and TLR ligands are increased or inhibited. This model describes mechanisms that explain how ITAM-coupled receptors regulate heterologous signalling pathways.
Data mining in brain imaging

Data mining in brain imaging is proving to be an effective methodology for disease prognosis and prevention. This, together with the rapid accumulation of massive heterogeneous data sets, motivates the need for efficient methods that filter, clarify, assess, correlate and cluster brain-related information. Here, we present data mining methods that have been or could be employed in the analysis of brain images. These methods address two types of brain imaging data: structural and functional. We introduce statistical methods that aid the discovery of interesting associations and patterns between brain images and other clinical data. We consider several applications of these methods, such as the analysis of task-activation, lesion-deficit, and structure morphological variability; the development of probabilistic atlases; and tumour analysis. We include examples of applications to real brain data. Several data mining issues, such as that of method validation or verification, are also discussed.
Incidence and risk factors of hepatocellular carcinoma in patients with primary biliary cirrhosis

We read with great interest the article by Cavazza et al., who demonstrated that an advanced histological stage was the only risk factor associated with the development of hepatocellular carcinoma (HCC) in patients with primary biliary cirrhosis (PBC) from two European centers. Similar results were described in a Japanese multicenter study by Shibuya et al. Although these studies suggest screening for HCC in patients with advanced-stage PBC, it is still uncertain whether there is a significantly increased risk of HCC development in patients with stage IV PBC cirrhosis versus patients with cirrhosis of other etiologies. We assessed in a single-center study the incidence of HCC in North American patients with stage IV PBC or autoimmune hepatitis (AIH) cirrhosis and compared it to the incidence of HCC in patients with hepatitis C virus (HCV) cirrhosis. Three hundred fifteen patients with HCV cirrhosis, 49 patients with AIH cirrhosis, and 52 patients with stage IV PBC were evaluated at the Cleveland Clinic between 2001 and 2007. Stage IV PBC cirrhosis was diagnosed when patients had positive serological and histological findings of cirrhosis or biochemical and radiological evidence of portal hypertension. Cirrhosis due to AIH was defined by positive serological and histological findings of cirrhosis or biochemical and radiological evidence of portal hypertension. HCC-free survival was analyzed from the moment of the diagnosis of cirrhosis in HCV, AIH, and PBC patients until death or transplantation. During a median follow-up of 3.6 years (with 25th and 75th percentiles of 1.8 and 6.3, respectively), 64 of 315 patients (20.3%) with HCV cirrhosis, 2 of 49 patients (4.1%) with AIH cirrhosis, and 4 of 52 patients (7.7%) with PBC cirrhosis developed HCC. The annual cumulative incidence of HCC was 1.1% in patients with AIH cirrhosis, 1.5% in patients with PBC cirrhosis, and 4.0% in patients with HCV cirrhosis (Fig. 1). This study has shown that although patients with stage IV PBC cirrhosis develop liver cancer, the risk is significantly lower in comparison with the risk for patients with HCV cirrhosis. The results of our study are discordant with a previously reported Spanish series in which the risks of HCC were similar in patients with late-stage PBC and in patients with HCV cirrhosis. We agree with Cavazza et al. that the low prevalence of PBC and the possible influence of geography on disease progression are confounding factors that may explain the divergent results in the literature. Future multicenter studies in North America with a longer follow-up period are necessary to validate these findings and better estimate the risk of HCC in PBC patients at an advanced histological stage.
Etiology of intestinal metaplasia at the gastroesophageal junction.

Background: Intestinal metaplasia occurs in the esophagus as a consequence of gastroesophageal reflux disease and in the stomach secondary to H. pylori infection. The etiology of intestinal metaplasia limited to the gastroesophageal junction or cardia (CIM) is disputed. We hypothesized that CIM has dual etiologies: gastroesophageal reflux in some, H. pylori infection in others, and that cytokeratin immunostaining can help to differentiate between these two etiologies. Methods: We defined CIM as the presence of intestinal metaplasia within cardiac mucosa on biopsy from an endoscopically normal-appearing gastroesophageal junction. Thirty patients with CIM who had multiple biopsy specimens taken from the esophagus, gastroesophageal junction, and stomach were identified. Tissue blocks from biopsy specimens taken at the gastroesophageal junction were sectioned and immunostained for cytokeratins 7 and 20. The cytokeratin 7/20 staining of the CIM in each patient was determined to be either a Barrett's or non-Barrett's pattern. H. pylori infection was assessed by Giemsa staining of antral biopsy specimens. Results: H. pylori infection was present in 16 patients. A Barrett's cytokeratin 7/20 staining pattern in the CIM was present in only 46% of the H. pylori–positive patients, as compared to 86% in the 14 patients with CIM and no H. pylori (p = 0.025). Objective evidence of reflux disease was present in 71% of patients with CIM and no H. pylori, as compared to 31% of patients with H. pylori. Conclusions: The two different patterns of cytokeratin 7/20 staining found in patients with CIM support the concept of dual etiologies for CIM. A Barrett's staining pattern was associated with objective evidence of gastroesophageal reflux and the absence of H. pylori, suggesting that cytokeratin 7/20 immunostaining is useful to determine the likely etiology of CIM.
Student Evaluations of Teaching and the Cognitive Level of Economics Courses

The Journal of Economic Education of Fall 1973 was devoted to the subject of student evaluations of teachers. That issue has engendered a great many papers, only a few of which can be published in the JEE because of space limitations. Michael Everett's report is not a mere replication of previous research on the subject, but adds a new dimension—the possible effect of student evaluations on the cognitive level of college economics courses. His finding that students may favor professors who emphasize lower level cognitive material will surely be distressing to many teachers, and should cause sober reflection on the part of administrators and others involved in establishing faculty evaluation procedures and policies.
Post-resuscitation right ventricular dysfunction: delineation and treatment with dobutamine

Abstract Background: Left ventricular dysfunction after resuscitation from cardiac arrest has been well described. Treatment with dobutamine improves post-resuscitation left ventricular function. Right ventricular function following resuscitation has not been investigated. The purposes of this study were to examine right ventricular function following resuscitation and determine whether dobutamine would improve post-resuscitation right ventricular function. Methods and results: Right ventricular function was measured in 28 swine (29±1 kg) before and after resuscitation from 15 min of untreated ventricular fibrillation. Twelve animals received dobutamine at 10 mcg/kg/min while 16 animals served as untreated controls. Among controls, right ventricular dysfunction post-resuscitation was demonstrated by a decrease in right ventricular ejection fraction and an increase in right ventricular end-diastolic pressure. Among animals treated with dobutamine, there was a significant improvement in right ventricular function post-resuscitation compared to untreated controls. Conclusions: This study establishes that right ventricular systolic and diastolic dysfunction does occur after prolonged cardiac arrest from ventricular fibrillation. Dobutamine can ameliorate post-resuscitation right ventricular dysfunction.
Link homology and Frobenius extensions

Author(s): Khovanov, Mikhail | Abstract: We explain how rank two Frobenius extensions of commutative rings lead to link homology theories and discuss relations between these theories, Bar-Natan theories, equivariant cohomology and the Rasmussen invariant.
The construction of knowledge in neurology: implications for hypermedia system development

This paper describes some elements of routine practice in neurology. How neurologists link CNS structure and function poses technical and conceptual issues for hypertext developers. These issues, particularly the need for developers to better understand routine thought and action in medicine, are taken up here.
Competencies and interest in a problem-focused undergraduate research methods criminal justice course: Two assessments

This study reports on two efforts, in a problem-centered undergraduate criminal justice research methods course, to gauge students' skills in understanding graphical data display and quasi-experimental designs. The problems addressed were drunk driving and handguns. Results show a moderate level of skill by students at course conclusion, but the weak quasi-experimental design precludes confirming the skills were acquired because of the course itself. Students did, however, report increased interest in the two problems because of course coverage. The approach described here may help bridge the gap between skill vs. content vs. process centered views on criminal justice as a liberal arts major.
A recurrent craniopharyngioma illustrates the potential usefulness of urinary matrix metalloproteinases as noninvasive biomarkers: case report.

OBJECTIVE Matrix metalloproteinases (MMPs) are a class of enzymes involved in angiogenesis, tumor growth, and metastasis. Recent reports indicate that urinary MMPs predict the presence of several types of tumors, including those of the breast, prostate, and bladder. Ongoing protocols at our institution are evaluating the efficacy of urinary MMPs as diagnostic markers for brain tumors and gastrointestinal disease. CLINICAL PRESENTATION An 8-year-old girl underwent transsphenoidal resection of a craniopharyngioma at the age of 6 years with radiographic gross total resection. Two years later, her urine was analyzed for MMPs as part of an evaluation for gastrointestinal complaints. Despite normal gastrointestinal evaluation results, her urinary MMP levels were markedly elevated. She subsequently sought treatment for recurrent craniopharyngioma. INTERVENTION The craniopharyngioma was resected again. Approximately 1 year after surgery, no sources of the elevated MMPs have been found other than the recurrent craniopharyngioma. Follow-up analysis of urinary MMPs demonstrated clearing of markers concordant with tumor treatment. CONCLUSION We report the finding of elevated urinary MMPs in the setting of a recurrent craniopharyngioma. These biomarkers correlate with the presence of disease, clear with treatment, and can be tracked from source tissue to urine. The findings of this case support the hypothesis that urinary MMPs may be a useful predictor of the presence or recurrence of brain tumors. To our knowledge, this is the first report supporting the proof-of-principle concept that urinary MMPs may have potential usefulness in predicting the presence of brain tumors, expanding the spectrum of tumors capable of being diagnosed with this technique.
Surface roughening in shadowing growth and etching in 2 + 1 dimensions

Through numerical calculations and Monte Carlo simulations, we examine the roughening behavior of a shadowing model, with lateral growth, for (2 11)-dimensional systems. The results show that the roughening growth exponent b51 for growth and b50 for etching. For the Monte Carlo simulation of the growth model, tall columns are formed, and the correlation length obeys j}(t2t 0) 1/z , with 1/z50.9360.1. For the Monte Carlo simulation of the etching model, we obtain 1/z50, and the height-height correlation function H(r )i s proportional to log(r) for r!j. The results are compared to previous computational studies of shadowing and to experimental studies of sputter deposition.
Explicit methods for the solution of the generalized Cauchy–Riemann equations and simulation of inviscid rotational flows

Abstract Different levels of approximations for inviscid rotational flows are discussed. The generalized Cauchy–Riemann equations, consisting of the continuity equation and the definition of the vorticity are considered. Artificial time dependent terms are added to integrate the system to steady state. The system is also augmented with artificial viscosity terms for numerical stability and to avoid odd/even decoupling of central differences of first-order derivatives. Additional artificial viscosity is needed to capture shock waves. Explicit integration of the augmented system by two methods is studied. Numerical results for inviscid flow with non-uniform far field conditions are presented. Both methods are suitable for computation on parallel machines.
Changing ratio of human chorionic gonadotropin subunits synthesized by early and full-term placental polyribosomes

Summary Subunits of hCG 1 were synthesized in vitro by incubating placental polyribosomes in a cell-free system with [ 3 H]leucine. The α and β subunits were precipitated by specific antisera and resolved on SDS-polyacrylamide gels, yielding single radioactive peaks at 10,000 and 16,000 daltons molecular weight. The α and β subunits accounted for 5 and 4%, respectively, of total incorporation into protein by first-trimester ribosomes, but only 1.3 and 0.6%, respectively, by full-term ribosomes. This reflects the declining maternal blood levels of hCG in late pregnancy. The change in α:β ratio from 1.2 to 2.3 suggests uncoordinated synthesis of the subunits and coincides with the appearance in the plasma of free α subunits in the third trimester.
Short-term effects of burn season on flowering phenology of savanna plants

We examined the effect of season of burn on flowering phenology of groundlayer species, in the year following burns, in a mesic-sand Midwestern oak savanna. Burn treatments were fall, early-season, growing-season, late-season, and 1 or 5 years after a prior early-season wildfire. For these treatments, we compared the number of flowering stems and of flowers for species overall, for the 20 most prolifically flowering species, as well as for species grouped by flowering phenoperiods, and by growth form. Growing-season burn had a significant negative effect on number of flowering stems and total number of flowers. This effect occurred when either the burn occurred during the flowering season or during the season prior to the flowering phenoperiod. Tradescantia ohiensis showed expedited flowering and Phlox pilosa showed delayed flowering in response to early-season burning. Flowering of early shrubs was reduced by the previous fall and early-spring fires, while flowering of mid-season blooming shrubs was reduced by the early- and growing-season burns. Vaccinium and Gaylussacia, early-flowering shrubs, produced fewer flowers 1 year after than 5 years after an early-season burn. Arabislyrata showed reduced flowering from the early-season burn. We also found four instances where the early-spring burn effect on flowering was more severe than the fall burn effect, suggesting that many frequent early-season burns may be deleterious to flowering and reproduction of some species. Burns occurring too frequently in the same season could negatively affect future flowering and reproduction of these plant species.
The online revolution: education for everyone

In 2011, Stanford University offered three online courses, which anyone in the world could enroll in and take for free. Together, these three courses had enrollments of around 350,000 students, making this one of the largest experiments in online education ever performed. Since the beginning of 2012, we have transitioned this effort into a new venture, Coursera, a social entrepreneurship company whose mission is to make high-quality education accessible to everyone by allowing the best universities to offer courses to everyone around the world, for free. Coursera classes provide a real course experience to students, including video content, interactive exercises with meaningful feedback, using both auto-grading and peer-grading, and a rich peer-to-peer interaction around the course materials. Currently, Coursera has over 80 university and other partners, and 4 million students enrolled in its nearly 400 courses. These courses span a range of topics including computer science, business, medicine, science, humanities, social sciences, and more. In this talk, I'll report on this far-reaching experiment in education, and why we believe this model can provide both an improved classroom experience for our on-campus students, via a flipped classroom model, as well as a meaningful learning experience for the millions of students around the world who would otherwise never have access to education of this quality.
Aldosterone mediates an increase in [3H]ouabain binding at Na+, K+ -ATPase sites in the mammalian inner ear

Na+,K+-ATPase has been implicated in the maintenance of high [K+], low [Na+] in endolymph of the inner ear, ionic properties condered to support transduction by the receptor cells6. In exocrine ion-transporting epithelia, Na+,K+-ATPase activity is modulated by aldosterone mineralocorticoid hormone31. In the present study, the effect of alteratio of serum aldosterone levels on Na+, K+-ATPase in ion-transporting regions of the mammalian inner ear was investigated. A high Na+/low K+ diet offered ad libitum for 5 days was utilized to significantly decrease serum aldosterone in male Hartley guinea pigs compared to controls. An injection of aldosterone (10 μg/100 g b.wt.) 21 h prior to sacrifice resulted in significant elevation of serum aldosterone over that obtained with the high Na+/low K+ diet. Binding of [3H]ouabain, a specific inhibitor of Na+,K+-ATPase, was significantly elevated in microdissected lateral wall of the basal turn of the cochlea and in the ampulla of the semicircular canal, for aldosterone-injected vs. vehicle-injected animals. Serum [Na+] and [Cl−] were elevated in animals on the high Na+/low K+ diet and unaltered by administration of exogenous aldosterone. The enhancement of ouabain binding in inner ear tissues observed in aldosterone-injected animals, therefore, did not appear to reflect an alteration of serum electrolytes per se. The results of these experiments are consistent with the hypothesis that aldosterone increases the number of Na+,K+-ATPase sites in ion-transporting epithelia of the mammalian cochlea and semicircular canal.
Emotional and Behavioral Adjustment in Typically Developing Siblings of Children with Autism Spectrum Disorders

Research findings describing the emotional and behavioral functioning of typically developing (TD) siblings of children with autism spectrum disorders (ASD) are contradictory. Methodological issues, such as small study sample sizes and reliance on parent report, may contribute to inconsistent findings. The purpose of this study was to use parent and teacher report to describe presence of internalizing and externalizing behaviors among a large sample (n = 486) of TD siblings of children with ASD. Results indicated that siblings did not exhibit a disproportionate prevalence of internalizing or externalizing symptoms in comparison to the standardization sample of the rating scale. The presence of a sibling with an ASD may not be considered a risk-factor for adjustment problems among TD siblings.
The genetics of otitis media.

There is significant evidence from epidemiologic, anatomic, physiologic, and immunologic studies that susceptibility to recurrent episodes of acute otitis media (OM) and persistent OM with effusion is largely genetically determined. The genetics of OM are most likely complex, i.e., many genes are probably contributing to the overall phenotype. The knowledge of a hereditary component has important implications because closer surveillance of children at risk for OM could result in earlier detection and treatment. Further, once OM susceptibility genes have been identified it may be possible to develop molecular diagnostic assays that could enable the clinician to identify the child at high risk for OM and to develop more focused treatments in the future.