cssi/SciSciGPT-SciSciNet huggingface dataset:
The impact of nonclinical factors on practice variations: The case of hysterectomies

Abstract OBJECTIVE: This study investigates the role of nonclinical factors (physician characteristics) in explaining variations in hysterectomy practice patterns. DATA SOURCES AND STUDY SETTING: Patient discharge data are obtained from the Arizona state discharge database for the years 1989-1991. Physician data are obtained from the Arizona State Medical Association. The analyses are based on 36,104 cases performed by 339 physicians in 43 hospitals. STUDY DESIGN: This article measures the impact of physician factors on the decision to perform a hysterectomy, controlling for a host of patient and hospital characteristics. Physician factors include background characteristics and training, medical experience, and physician's practice style. Physician effects are evaluated in terms of their overall contribution to the explanatory power of regression models, as well as in terms of specific hypotheses to be tested. DATA COLLECTION: The sources of data were linked to produce one record per patient. PRINCIPAL FINDINGS: As a set, physician factors account for a statistically significant increase in the explanatory power of the model after addition of patient and hospital effects. Parameter estimates provide further support for the hypothesized effects of physicians' background, experience, and practice characteristics. CONCLUSIONS: Overall, the results confirm that nonclinical (physician) factors play a statistically significant role in the hysterectomy decision. Substantively, however, these factors play a smaller, secondary role compared to that of clinical and patient factors in explaining practice variations in hysterectomies. The results suggest that efforts to reduce unnecessary hysterectomies should be directed at identifying the appropriate clinical indications for hysterectomy and disseminating this information to physicians and patients. This may require such intervention strategies as continuing clinical education, promulgation of explicit practice guidelines, peer review, public education, and greater understanding and inclusion of patient preference in the decision process.
Spanish as an International Language: Implications for Teachers and Learners by ARTEAGA, DEBORAH, & LUCÍA LLORENTE

The article reviews the book "Spanish as an International Language: Implications for Teachers and Learners," by Deborah Arteaga and Lucia Llorente.
Effect of test environment on the surface breakdown characteristics of photoconducting silicon

The influence of test environments (vacuum and air) on the pre-breakdown and breakdown characteristics of photoconducting p-type silicon samples were investigated. The surface of all the samples were polished (mechanical and chemo-mechanical) to a fine finish (0.06 micrometers ) and cleaned by ultrasonic and RCA methods. The role of thermally grown thin amorphous SiO2 layer and the insulating epoxy layer on the breakdown properties were also investigated. The breakdown characteristics of the samples were found to be modified by the surface condition while testing in vacuum. Contrarily, the influence of those surface parameters on the breakdown properties of the same samples were found to be insignificant when the test environment was air. In general, the samples exhibited higher breakdown strength in air compared to that in vacuum. Besides, the lock-on behavior of the samples was identified only in vacuum (not in air) environment.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The Family History: Reemergence of an Established Tool

Genetics has transformed the use of family history information and has led to the reemergence of the detailed genetic family history. It is critical that public and professional educational efforts to increase family history awareness and working knowledge are prioritized. Patient maintenance of the pedigree provides increased patient awareness and facilitates some of the limitations associated with conventional medical history ascertainment, ultimately improving health care and research. The increasing use of genetic screening promises to cultivate a paradigm shift in medical treatment emphasizing primary prevention and early intervention. Appreciation of the family history is necessary to make this important advance.
GABAergic neurons in the lateral superior olive of the hamster are distinguished by differential expression of gad isoforms during development.

γ-Aminobutyric acid (GABA) is an inhibitory neurotransmitter that is synthesized by two isoforms of glutamic acid decarboxylase (GAD), GAD65 and GAD67. Using in situ hybridization and immunocytochemical techniques in hamsters, we investigated the postnatal development of GAD isoforms within the lateral superior olive (LSO) where GABAergic neurons form part of a descending efferent projection to the cochlea. In the neonatal hamster LSO, GAD67 immunoreactivity, GAD67 transcript labeling, and intense GABA immunostaining are at low levels. However, robust GAD65 mRNA expression is found throughout the LSO during the early postnatal period. The neonatal GABAergic expression patterns are in stark contrast to the adult where the LSO has robust GAD67 mRNA expression and weak GAD65 mRNA expression. Cells exhibiting intense GABA immunolabeling were also found in the same LSO locations as robust GAD67 mRNA expression and intense GAD67 immunoreactivity. Additionally, GAD67-positive cells in the LSO were retrogradely labeled from the cochlea confirming that these cells are a part of the lateral olivocochlear system. The late onset of GAD67 expression and intense GABA immunoreactivity in LSO neurons are consistent with the relatively late maturation of the lateral olivocochlear neurons inferred from previous studies. During development, these data lead us to conclude that the GABAergic portion of the lateral olivocochlear system is distinguished by preferential GAD67 expression, intense GABA immunoreactivity, and relatively late postnatal onset.
Stability of food allergens to digestion in vitro

An integral part of the safety assessment of genetically modified plants is consideration of possible human health effects, especially food allergy. Prospective testing for allergenicity of proteins obtained from sources with no prior history of causing allergy has been difficult because of the absence of valid methods and models. Food allergens may share physicochemical properties that distinguish them from nonallergens, properties that may be used as a tool to predict the inherent allergenicity of proteins newly introduced into the food supply by genetic engineering. One candidate property is stability to digestion. We have systematically evaluated the stability of food allergens that are active via the gastrointestinal tract in a simple model of gastric digestion, emphasizing the major allergens of plant-derived foods such as legumes (peanuts and soybean). Important food allergens were stable to digestion in the gastric model (simulated gastric fluid). For example, soybean beta-conglycinin was stable for 60 min. In contrast, nonallergenic food proteins, such as spinach ribulose bis-phosphate carboxylase/oxygenase, were digested in simulated gastric fluid within 15 sec. The data are consistent with the hypothesis that food allergens must exhibit sufficient gastric stability to reach the intestinal mucosa where absorption and sensitization (development of atopy) can occur. Thus, the stability to digestion is a significant and valid parameter that distinguishes food allergens from nonallergens.
Movement of the tube cell in the lily style in the absence of the pollen grain and the spent pollen tube

Our model proposes that pollen tube growth is a form of cell movement where the tube tip can be considered analogous to a migrating cell which leaves a trail of extracellular matrix (the spent pollen tube) behind. We demonstrate that the tube cell can convey the sperm cells to the ovule and effect fertilization even in the absence of the pollen grain and the spent pollen tube. Adhesion is an integral part of cell attachment and movement in animal systems. We show that in vivo-grown pollen tubes grow beneath the cuticle of the stylar transmitting tract epidermis and directly adhere to one another and the outer wall of the epidermal cells. A fibrous wall material is found to cover the tip of the pollen tube cell wall and the surface of the transmitting tract cells where the two adhere. Fixation methods to preserve adhesive compounds were used. The pollen-tubes grown in vivo, but not in vitro, show star-shaped clusters of F-actin microfilaments in the region back from the tip, as seen by rhodamine-phalloidin staining. These configurations are similar to focal adhesions seen in moving animal cells.
Brood recognition by contact pheromone in the red imported fire ant, Solenopsis invicta

Abstract The rather unspecific fire ant brood pheromone assay of Glancey et al. (1970) could not be duplicated, probably because they confounded a food response with a brood response. A more specific assay for the brood recognition signal of the red imported fire ant, Solenopsis invicta Buren is described. Worker response in the assay was unaffected by altering social conditions in the colonies but demanded the presence of animal tissue in the ants' diet in order to be consistent. Evidence is presented for a nonvolatile contact brood pheromone that is distributed evenly over the pre-adult cuticle and whose potency is abruptly reduced with the shedding of the pupal skin at eclosion. The signal is completely lost within 72 hr of death.
Production and characterization of monoclonal antibodies against norsolorinic acid reductase involved in aflatoxin biosynthesis

Polyclonal antibodies against norsolorinic acid reductase (NSR), an enzyme responsible for the conversion of norsolorinic acid to averantin in the early stage of aflatoxin biosynthesis, were produced after immunizing rabbits with a semi‐purified NSR preparation. Immunochemical analysis of the enzyme extracts from Aspergillus parasiticus revealed that the antibodies reacted with several protein species, including bands corresponding to NSR activity. The ammonium sulfate‐cut IgG was further purified by passing it through a column armed with protein fractions containing immunoreactivity, but no enzyme activity, isolated from the A. parasiticus extracts that had been subjected to Sepharose gel filtration. After subtractive affinity chromatography, the purified antiserum reacted primarily with two protein bands (of molecular weight 43 and 48 kDa) and was capable of neutralizing the NSR activity. Enzyme‐linked immunosorbent assay (ELISA) analysis of various fungal extracts showed that the purified antiserum was...
Action of histamine on the mesenteric microvasculature.

Abstract The effect of known, reproducible doses of histamine (0.1–100 μg/ml base) on the permeability of the microvasculature of the cat and rat mesentery was examined in vivo using intravital fluorescence microscopy and in fixed sections from identifiable regions of the same tissue using electron microscopy. The percentage of animals in which extravasation of fluorescent serum albumin in response to histamine was observed was positively related to dose, with approximately half the animals responding to 2–5 μg/ml (rat) or 0.1–0.5 μg/ml (cat). Electron microscopy of sections of vessels exhibiting extravasation of fluorescent tracer in vivo revealed numerous gaps ranging in size from 0.5 to 1.0 μm between endothelial cells. Serial sections and computer three-dimensional reconstructions showed that these gaps occurred at endothelial junctions but with irregular geometry and involvement of “cords” of cytoplasm bridging some of the endothelial gaps.
The hippocampus is functionally connected to the striatum and orbitofrontal cortex during context dependent decision making

Many of our everyday actions are only appropriate in certain situations and selecting the appropriate behavior requires that we use current context and previous experience to guide our decisions. The current study examined hippocampal functional connectivity with prefrontal and striatal regions during a task that required participants to make decisions based on the contextual retrieval of overlapping sequential representations. Participants learned four sequences comprised of six faces each. An overlapping condition was created by having two sequences with two identical faces as the middle images. A non-overlapping condition contained two sequences that did not share any faces between them. Hippocampal functional connectivity was assessed during the presentation period and at the critical choice, where participants had to make a contextually dependent decision. The left hippocampus showed significantly increased functional connectivity with dorsal and ventral striatum and anterior cingulate cortex during the presentation period of the overlapping compared to the non-overlapping condition after participants knew the sequences. At the critical choice point of the overlapping condition, the left hippocampus showed stronger functional connectivity with the orbitofrontal cortex. These functional connectivity results suggest that the hippocampus may play a role in decision making by predicting the possibilities of what might come next, allowing orbitofrontal and striatal regions to evaluate the expected choice options in order to make the correct action at the choice point.
PAIR BONDS IN MONOGAMOUS APES: A COMPARISON OF THE SIAMANG HYLOBATES SYNDACTYLUS AND THE WHITE-HANDED GIBBON HYLOBATES LAR

Summary Descriptions of the social systems of gibbons (Hylobates, Hylobatidae) have typically emphasized generically uniform attributes such as 'monogamy' and 'territoriality'. This has prevented testing of the hypothesis that pair bonds differ in the siamang (Hylobates syndactylus) and the white-handed gibbon (Hylobates lar) (Chivers, 1972). I replace a description of sociality based on mating system and group size/composition with quantitative measurement of social interactions and spatial relations between wild adult males and females in three heterosexual pairs of siamang and two pairs of white-handed gibbons studied for 2.5 years at the Ketambe Research Station (Sumatra, Indonesia). Siamang pair bonds show greater heterosexual cohesion than those of white-handed gibbon as reflected in higher rates of affinitive interactions such as close proximity, relaxed physical contact, embraces, and
Potential in-hospital modes of transmission of legionella pneumophila. Demonstration experiments for dissemination by showers, humidifiers, and rinsing of ventilation bag apparatus

Abstract The mode of transmission of nosocomial legionellosis remains uncertain. Aerosolization of Legionella pneumophila by showers, humidifiers, and respiratory equipment rinsed in tap water was evaluated using plate-settling culture and air aspirator methods. All protocols simulated the actual hospital setting including use of humidifier equipment used in hospital patient rooms and water from faucets and showerheads in hospitals with nosocomial Legionnaires' disease. Protocols for humiditier and shower experiments mimicked the procedure actually used in hospitals by health care personnel. Showering failed to produce aerosols of L. pneumophila; however, portable humidifiers readily generated aerosols of L. pneumophila that disseminated throughout a two-bed patient room. Intensity of aerosolization directly correlated with the degree of L. pneumophila contamination of the tap water used to fill the humidifier. Rinsing of ventilation bag apparatus with tap water led to isolation of L. pneumophila from culture plates after the ventilation bags were squeezed. Thus, L. pneumophila could be aerosolized or directly instilled into a patient's bronchial tree following routine measures for cleaning ventilation bag apparatus with tap water. On the basis of these results, the use of humidifiers filled with tap water has been discontinued and sterile water is recommended for rinsing ventilation bag apparatus and tubing.
Narrow Victories and Hard Games: Revisiting the Primary Divisiveness Hypothesis:

The 2008 presidential election offers a unique opportunity to revisit the hypothesis that a divisive primary exacts a tolls on the party’s general election performance—neither party had a sitting president or vice president seeking the nomination, the Democratic nomination was contested all the way to the end, and advertising data provide a way to gauge both the intensity and tenor of the campaigns. In this article, we take advantage of these circumstances to distinguish between primaries that were competitive and those that were negative and find, contrary to the assumptions in the divisive primary literature, that a close contest does not imply a divisive one. Moreover, we find that Obama was helped by his tight battle with Clinton for the nomination and that the tone of the primaries bore no relationship to his general election performance.
Mapping uncertainties through the POM-SAT model of climate reconstruction from borehole data

Abstract. Borehole temperature-depth profiles contain information about the ground surface temperature (GST) history of a locale and can be employed in climate reconstruction. The borehole method of climate reconstruction assumes that the dominant heat transport mechanism in the upper few hundred meters of the earth's crust is conduction; mathematically, conduction is a compressive (information losing) mapping from the temperature-time space of GST to the temperature-depth profile (T−z). Because the mapping is compressive, multiple GST histories can map into the same T−z profile; the solution suffers from non-uniqueness. One means of dealing with the non-uniqueness problem is to limit the number of parameters sought in the solution space. However, even when only a single parameter (the pre-observation mean GST, or POM) is sought in the inversion, a certain amount of a priori information must be introduced prior to inverting for a GST history. In the POM-SAT method, a priori information introduced includes the surface-air temperature history (SAT), the thermal diffusivity of the conductive medium, and the reducing parameter used to remove the background (non-climatic) heat flux. I perform a set of Monte Carlo analyses to investigate how uncertainties in these a priori model parameters are mapped into the solution space of the POM-SAT method of climate reconstruction. Results indicate that uncertainties in the thermal diffusivity are generally reduced by an order of magnitude when mapped to the POM. Uncertainties in the SAT time series are approximately equivalent in magnitude to their projection onto the POM. However, uncertainties in the adjustment for the background (non-climatic) thermal regime are magnified by an order of magnitude in the POM solution-space. These results suggest a degree of prudence should be exercised in interpreting surface temperature histories from reduced borehole data.
Effects of Sampling Strategies on Estimates of Annual Mean Herbicide Concentrations in Midwestern Rivers

The effects of 10 sampling strategies on estimates of annual mean concentrations of the herbicides atrazine, alachlor, and cyanazine in selected midwestern rivers were tested. The accuracy of the strategies was computed by comparing time-weighted annual mean herbicide concentrations calculated from water samples collected from 17 locations on midwestern rivers, with simulated annual mean concentrations calculated for each sampling strategy, using Monte Carlo simulations. Monthly sampling was the most accurate strategy tested. The U.S. Environmental Protection Agency requires quarterly sampling for municipalities using surface water as a source of drinking water. Due to the seasonality of herbicide occurrence and transport, quarterly sampling underestimates annual mean herbicide concentrations in over 40% of the simulations. Three of the strategies tested showed that, relative to quarterly sampling, a more accurate representation of annual mean concentrations could be obtained by sampling more frequently during spring and early summer runoff and assuming zero herbicide concentration during late summer and winter months.
Kernel growth of in vitro cultured wheat spikes of cultivars with divergent source-sink limitations

Abstract A 50% reduction at anthesis in the main stem reproductive sink size of soft red winter wheat (Triticum aestivum L. em. Thell) elicits differential kernel size (KS) responses among cultivars. In this study, source levels were manipulated to evaluate cultivar source and sink limitations to kernel growth. Detached spikes of ‘Arthur’ (non-responsive, KS unaffected by 50% spikelet removal), ‘Caldwell’, ‘FL 302’ and ‘Adena’ (responsive, KS increases with 50% spikelet removal) cultivars were cultured in vitro from 14 days after anthesis (during endosperm cell expansion stage) to maturity with sucrose levels of 25, 50, 100 and 200 mM. Relative differences in KS among cultivars for each sucrose level were similar to those of field-grown plants at maturity. The KS of all in vitro cultured cultivars reached maximum at sucrose levels of 50 mM or greater; however, these kernels were 11–21% smaller than those of field-grown plants. On average, kernels on spikes cultured in 100 mM sucrose grew at the same rate as kernels on field-grown plants, but for a significantly shorter duration (22.8 vs. 31.7 days). Sucrose concentrations of peduncle and chaff tissues increased as sucrose levels increased. Compared to field-grown plants, peduncle and chaff tissues of cultured spikes averaged over all sucrose levels and cultivars had 4.6-fold greater water soluble carbohydrate concentration and 59% more tissue dry weight at maturity. Smaller kernels but abundant accumulation of water soluble carbohydrates in peduncle and chaff indicate that factors other than carbohydrate supply limited kernel growth of spikes cultured in vitro. When cultured in vitro, the non-responsive cultivar Arthur did not reach maximum KS at a lower sucrose concentration than the responsive cultivars. Thus, the apparent kernel growth limitation due to sink activity observed after partial spikelet removal of field-grown Arthur was not observed when spikes of this cultivar were cultured in vitro.
Fungal keratitis responsive to moxifloxacin monotherapy.

Traditionally, antibacterial agents have been considered to have no significant therapeutic effect against fungal pathogens. In fact, antibacterial agents are routinely used to supplement fungal culture media to enhance recovery of fungi. In the past, reports of cure of fungal keratitis by antibiotic therapy have been rare1, 2. In recent years, however, a number of cases of Fusarium keratitis have been reported to have responded to topical antibiotic therapy3–5. This report describes five cases of fungal keratitis cured with single agent therapy with topical moxifloxacin 0.5%.
Operational preferences for ATC data link equipped aircraft: Severe weather reroutes

The Next Generation Air Transportation System (NextGen) requires synchronized investments from the Federal Aviation Administration (FAA) and the flight operators who transit the National Airspace System (NAS). Flight operators have emphasized in public dialog that they are not willing to equip aircraft with avionics unless the investing operator directly gains monetized benefits and a competitive advantage. While financial incentives have been considered as a mechanism to close the equipage business case of meeting a threshold of return on investment, the FAA has proposed that operational incentives may be an appropriate mechanism to provide additional assurances to those who invest in NextGen technologies. This research evaluates one potential operational incentive as applied to traffic flow management reroute prioritization for Air Traffic Control (ATC) data link-equipped aircraft in a severe weather scenario. During severe convective weather, many airborne flights need to be rerouted and yet-to-depart flights need a new flight plan and/or ground delay. Prioritizing the scarce resource of constrained sector capacity by equipage capability (rather than by “first come first served”) enables data link equipped aircraft to receive shorter reroutes and less departure delay than unequipped aircraft. Due to decreased workload associated with ATC data link aircraft, increased controller productivity should result in the ability to handle more traffic, increasing NAS throughput and capacity. Prioritizing equipped aircraft is not simply a transfer of value from one aircraft group to another; but, of rewarding investment in system enhancing capabilities by pioneering operators. By prioritizing access to constrained airspace to equipped aircraft and encouraging use of ATC data link communications, greater NAS throughput is achieved than would be possible in a voice-only environment. The overall effect is “doing well by doing good” where equipped aircraft are provided better services while improving overall airspace efficiency.
Clostridium difficile infection increases mortality risk in lung transplant recipients

Background Clostridium difficile infection (CDI) and associated mortality in solid organ transplant recipients is rising, but data are scarce in lung transplant recipients. We aimed to characterize CDI and its effect on mortality in a large cohort of lung transplant recipients. Methods Lung transplant recipients were identified from our transplant database from 2000 to 2011. Cox proportional hazard models were used to calculate hazard ratios for CDI and death after adjusting for potential confounders identified from bivariate analysis. Results We identified 388 patients (196 female, 192 male), with a median age of 56 years (range, 8–75 years), during the study period. CDI developed after transplant in 89 (22.9%), with 27 (7.0%) developing CDI during the initial hospitalization at a mean diagnosis of 12.7 ± 11.4 days. Incidence varied widely each year (median, 24%; range, 5%–32%), with the highest rates in 2007 to 2008. Post-operative length of stay was identified as a significant predictor of CDI (hazard ratio [HR], 1.02; 95% confidence interval [CI], 1.01–1.03). Early CDI was an independent significant predictor of death (HR, 1.96; 95% CI, 1.14–3.36) as well as CDI anytime after transplant (HR, 1.61; 95% CI, 1.02–2.52). Conclusions CDI rates varied widely from 2000 through 2011, with the highest rates in 2007 to 2008. Lung transplant recipients who developed CDI had a higher risk of death, especially when CDI occurred in the first 6 months after transplant.
An avian and aphrodisian reading of Homer's Odyssey

The meaning, even the sheer presence, of birds in the Odyssey has been ignored by all but a few scholars. A similar statement could be made about an aphrodisian reading of the text. Yet Homer felt that birds were deeply significant, often as symbols of Aphrodite. Examination of these meanings leads to a unique understanding of essential, underlying values in Homeric culture. Such efforts are consonant with the anthropological goal of understanding how culturally defined natural phenomena work in the articulation, expression, and condensation of powerful, culturally defined emotions.
Determining the constitutive response of polymeric materials as a function of temperature and strain rate

Compression stress-strain measurements have been conducted on two commercial high temperature thermoplastic polymers (polyamideimide (PAI) and partially crystalline polyetheretherketone (PEEK)) as a function of temperature (-55°C to 300°C) and strain rate (0.001 s -1 to 2500 s -1 ). A split-Hopkinson pressure bar (SHPB) was used to achieve strain rates of about 2500 s -1 and conventional testing machines were used for strain rates from 0.001 s -1 to 1 s -1 . A large variation in the mechanical response was observed over the range of temperatures tested for both polymers showing yield and plastic deformation below the glass transition temperature (T g ). Above T, both thermoplastic polymers exhibited increasing loading moduli with increasing strain rate or decreasing temperature. T g appears to shift to higher temperatures as the strain rate increases. Below T g both thermoplastic polymers exhibited a yield-type behavior followed by anelastic deformation. PEEK was seen to be more sensitive to strain rate and temperature than PAI. A range of different flow stress versus strain behaviors was observed at different temperatures and strain rates.
UPSILON PRODUCTION IN pp COLLISIONS AT LHC

This is a continuation of recent studies of ϒ(nS) production at the LHC in pp collisions. Our previous studies were for 2.76 TeV, while the present predictions are for 7.0 TeV collisions.
The importance of tamoxifen to a cisplatin-containing regimen in the treatment of metastatic melanoma

The combination of dacarbazine (DTIC, 220 mg/m2) and cisplatin (DDP, 25 mg/m2) IV daily for 3 days every 3 weeks, carmustine (BCNU, 150 mg/m2) IV every 6 weeks, and tamoxifen (TAM, 10 mg orally twice daily) produced a 50% objective response rate in patients with metastatic melanoma. Associated with this treatment, there was a high incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE). In an effort to reduce this toxicity, this regimen minus TAM was studied, and the results are reported. Twenty of twenty patients are evaluable for response and toxicity. There was one complete response (CR) lasting 5+ months and one partial response (PR) lasting 4+ months for an overall response rate of 10% (95% confidence limits, 1.23% to 31.70%). Two patients exhibited a mixed response and three patients developed disease stabilization lasting 4 to 10 months. Toxicity was similar to the original study except that no patients developed DVT or PE. This statistically significant (Fisher's exact test [two-tail] P = 0.008) decrease in the response rate by comparison with that achieved with the TAM-containing regimen may signal an essential role of TAM in this regimen. TAM may be acting in synergy with cisplatin through its calcium channel-blocking properties. TAM should be included as described in the initial reports, and the patients should be carefully observed for vascular complications.
Methodological issues in etiologic studies of diet and colon cancer

Abstract Recently, several hypotheses regarding the role of diet in the etiology of cancer have emerged. Here we review the principal methods available tor studying these hypotheses in human populations. Particular attention is given to the strengths and weaknesses of ecologic analyses, diet interview and other clinical and experimental approaches. Although the contributions of these methods are examined in the context of their application to research on colon cancer, the issues are of general relevance to the study of diet and cancer. For each method examined, potential sources of error are noted and suggestions for improving their reliability and validity are discussed. Since each method is vulnerable to error, a research program utilizing both existing and new methodological approaches is required if the role of diet in cancer etiology is to be understood.
Application of fractal concepts to polymer statistics and to anomalous transport in randomly porous media

We consider the application of fractal concepts to polymer statistics and to anomalous transport in randomly porous media. It is found that answers to interesting physics questions can be expressed in terms of several new fractal dimensions (in addition to “the” fractal dimensiond f ): (1)d , the fractal dimension of the backbone, arises in connection with electric current flow, (2)d red, the fractal dimension of the singly connected bonds in the backbone, arises in connection with its equivalence to the thermal scaling power, (3)d E, the fractal dimension of the of the elastic backbone, (4)d u, the fractal dimension of the unscreened perimeter, arises in connection with the viscosity singularity at the gelation threshold, (5)d min the fractal dimension of the minimum path (or “chemical distance”) between two sites, arises in co-nnection with the Aharony-Stauffer conjecture, (6)dw, the fractal dimension of a random walk, (7)d G, the fractal dimension of growth sites that arise as a random walk creates a cluster. Relations among these fractal dimensions are discussed, some of which can be proved and others of which are conjectures whose validity has been established only in certain limiting cases.
On the Functional logdet and Related Flows on the Space of Closed Embedded Curves on S2

Abstract For any two-dimensional Riemannian manifold ( M , g ) we introduce a new functional, h g , on the space of closed simple nonparametrized curves on M . This functional associates to any simple curve Γ the regularize determinant of the Laplace operator on the manifold obtained by cutting M along Γ and imposing Dirichlet boundary conditions. When M is of genus zero we derive a formula for the variation of h g , we prove that the critical points are conformal circles (i.e., the curves which, with respect to the unique metric of constant curvature 1 in the conformal class { e 2α g :α ∈ C ∞ ( S 2 , R )} of g , have constant geodesic curvature), and that the hessian of the functional at a critical point is nondegenerate in directions normal the critical submanifold (Theorem 1.1). We also construct smooth flows on the space of nonparametrized curves retracting the space onto the critical sub-manifold and show that they are gradient-like for our function. These flows deform a given closed embedded curve on S 2 to a conformal circle keeping the area of the domain bounded by each curve of the deformation constant (Theorem 1.3).
Can reducing black carbon emissions counteract global warming

Field measurements and model results have recently shown that aerosols may have important climatic impacts. One line of inquiry has investigated whether reducing climate-warming soot or black carbon aerosol emissions can form a viable component of mitigating global warming. We review and acknowledge scientific arguments against considering aerosols and greenhouse gases in a common framework, including the differences in the physical mechanisms of climate change and relevant time scales. We argue that such a joint consideration is consistent with the language of the United Nations Framework Convention on Climate Change. We synthesize results from published climate-modeling studies to obtain a global warming potential for black carbon relative to that of CO2 (680 on a 100 year basis). This calculation enables a discussion of cost-effectiveness for mitigating the largest sources of black carbon. We find that many emission reductions are either expensive or difficult to enact when compared with greenhouse gas...
The Austere Demagogue: Thucydides on the Uses and Abuses of Periclean Rhetoric

In this article I draw attention to the way Thucydides characterizes Pericles as a leader who manipulates public passions to produce both passivity and dependence. To elicit this view of Pericles, the student of Thucydides needs to pay attention to the text's key instances of Periclean rhetoric, which the historian has crafted most assiduously. Whether the historical Pericles actually applied rhetoric in this manner is beside the point; it is the historian rather who conveys a characterization of Periclean leadership in this way. Nor is it a coincidence that this characterization draws attention to rhetoric: It is the rhetorical manipulation of the public, after all, that poses a grave threat to democracy, in this view. Interpreted in a certain, defensible, way, Thucydides' text casts a pessimistic light on the relationship between rhetorically gifted leader and the public. In addition, the text affords us insights into a variant of subtle demagogic manipulation that has been rare and rather elusive. The ...
Late positive event-related potentials after commissural section in humans

The lateral distribution of the P300 component of the event-related brain potential (ERP) was studied in five epileptic patients whose corpus callosum had been surgically sectioned and in seven neurologically intact controls. The P300 was elicited in an auditory “oddball” task using high-and low-pitched tones and in a visual oddball task in which target words were presented either to the left or right visual fields, or to both fields simultaneously. Commissurotomy altered the normal pattern of bilaterally symmetrical P300 waves over the left and right hemispheres, but in a different manner for auditory and visual stimuli. The auditory P3 to binaural tones was larger in amplitude over the right than the left hemisphere for the patients. In the visual task, the laterality of the P300 varied with the visual field of the target presentation. Left field targets elicited much larger P300 amplitudes over the right than the left hemisphere, as did bilateral targets. In contrast, right field targets triggered P300 waves of about the same amplitude over the two hemispheres. The overall amplitude of the P300 to simultaneous bilateral targets was less than the sum of the individual P300 amplitudes produced in response to the unilateral right and left field targets. These shifts in P300 laterality argue against the view that the P300 is an index of diffuse arousal or activation that is triggered in both hemispheres simultaneously irrespective of which hemisphere processes the target information. The results further demonstrate that the P300 does not depend for its production on interhemispheric comparisons of information mediated by the corpus callosum, as suggested recently by Knight et al. (1989).
Perturbation theory for multiphoton ionization without knowledge of the final-state wave function

We show how the inclusive rate of decay of an atomic system by absorption of any number N of photons can be calculated at $N\mathrm{th}$ order of perturbation theory without employing the final-state (continuum) wave function. We give a computationally useful formula which involves only the response function for a system perturbed by absorption of N photons. In the case of a two-electron system, the contributions to the inclusive rate from individual channels can be separated using projection operators.
Hebbian synaptic modification in cortical circuits and memory-guided behavior in spatial alternation and delayed non-match to position

Numerous studies have focused on the mechanisms of Hebbian synaptic plasticity within the hippocampal formation and neocortical structures, but the specific role of this plasticity in regulating behavior remains unclean. This paper presents a model demonstrating how Hebbian synaptic modification could mediate the context-dependent retrieval of episodes necessary for memory guided behavior in specific tasks, and could also contribute to prefrontal mechanisms for regulation of goal directed behavior. This modeling effectively links neurophysiological data to the functional role of Hebbian synaptic modification and theta rhythm oscillations. The model simulates data on neuronal spike firing and field potentials in the hippocampus, including: 1) the phenomenon of theta phase precession of place cells: 2) the context-sensitivity of neuronal firing ("splitter cells") during spatial alternation: and 3) the selective changes in theta phase precession across different trials on the same day.
Internal and external trauma to the larynx.

Trauma affects the larynx internally through vocal misuse, chemical and thermal burns, and intralaryngeal instrumentation; externally through physical violence, industrial accidents and automobile collisions. Occupational laryngeal trauma is that seen in the larynges of professional voice users such as singers, preachers, lawyers, school teachers, politicians, telephone operators, sales people, credit managers and auctioneers. Particularly common are the nodules on the vocal cords of housewives with several small children! In industry, voice changes and laryngeal pathology are common in voice abusers such as foremen, women assembly line workers, men working near a steam jack and engineers and firemen in cabs of diesel locomotives.1 Bridging these two categories of white collars and blue shirts are representatives in management-labor relations who have additional reason to develop laryngeal trauma.
Subgroup B Adenovirus Type 35 Early Region 3 mRNAs Differ from Those of the Subgroup C Adenoviruses

Adenovirus type 35 (Ad35) is a member of Ad subgroup B, DNA homology cluster B2. The B2 Ads are unique in that they are isolated most frequently from immunosuppressed individuals such as AIDS patients and bone marrow transplant recipients and in that they have a tropism for the urinary tract. One region of the Ad genome which may influence serotype specific pathology is early region 3 (E3). E3 of subgroup C Ad2 and Ad5 has been shown to encode proteins which counteract the immune response to Ad infection. While a great deal is known about gene expression of the subgroup C Ad E3s, little is known about the E3 gene expression from the subgroup B Ads. Although some E3 open reading frames (ORFs) are shared between subgroups B and C, there are additional ORFs that appear in subgroup B. This paper demonstrates the results of an analysis of gene expression from the Ad35 E3 and describes differences in splicing and polyadenylation between the Ad35 and Ad2 E3s. RT-PCR, cDNA sequencing, RNase protection, 3'RACE, and Northern blotting techniques were utilized to identify, quantify, and determine the structure of six Ad35 E3 mRNAs predicted to encode at least seven proteins. A common intron that is removed during splicing of the subgroup C E3 mRNAs is not removed from Ad35 E3 mRNAs, and only one E3 polyadenylation signal is present in the Ad35 E3 while two polyadenylation signals are used in the formation only one E3 polyadenylation signal is present in the Ad35 E3 while two polyadenylation signals are used in the formation of subgroup C E3 mRNAs. The quantity of individual mRNAs encoding homologous proteins for Ad35 and Ad2 also differ substantially, presumably because of the absence in Ad35 of cis-acting signals which have been shown to be important for regulation of Ad2 E3 pre-mRNA processing. Such information should contribute to an understanding of the role the E3 plays in determining subgroup B Ad pathogenesis in general and Ad35 pathogenesis in particular.
Autoantibody targets and their cancer relationship in the pathogenicity of paraneoplastic retinopathy

Paraneoplastic retinopathies (PR), including cancer-associated retinopathy (CAR) or the closely related melanoma-associated retinopathy (MAR) occur in a small subset of patients with retinal degeneration and systemic cancer. This autoimmune syndrome is characterized by sudden, progressive loss of vision in association with circulating anti-retinal autoantibodies. The PR syndromes are heterogeneous, may produce a number of ocular symptoms, and may be associated with several different neoplasms, including lung, breast, prostate, gynecological, and colon cancer, melanoma, and hematologic malignancies. We examined the onset of retinopathy in correlation to the diagnosis of cancer and the presence of specific anti-retinal autoantibodies in PR patients. In some patients without diagnosed malignant tumors, the onset of ocular symptoms and the presence of autoantibodies preceded the diagnosis of cancer by months to years, including anti-recoverin, anti-transducin-α, and anti-carbonic anhydrase II antibodies. Although anti-retinal autoantibodies may not be a good predictor of a specific neoplasm, they can be used as biomarkers for different subtypes of retinopathy. Identification of autoantibodies involved in autoimmune-mediated PR will help elucidate the mechanisms underlying the PR syndromes and develop targeted therapies for these sight-threatening disorders.
Surface roughness of two polished ceramic materials.

Conventional and CAD-CAM ceramic restorations often require adjustments that result in a need to reduce surface roughness. Surface roughness resulting from five polishing systems on two ceramics was assessed. Disks of Ceramco II and Dicor MGC ceramic blocks were polished with five combinations of 45, 25, and 10 μm diamonds; a 30-fluted carbide; three silicon carbide-impregnated rubber points; 4 and 1 μm diamond gels; and an aluminum oxide point and two aluminum oxide pastes. Five profilometer average roughness measurements (Ra) were taken of five replications of each step in each sequence. Controls were autoglazed Ceramco II and Dicor MGC ceramic specimens milled with a Cerec diamond wheel. Feldspathic porcelain could be polished smoother than glazed. Dicor ceramic could be polished smoother than Ceramco II ceramic. Finishing diamond points followed by diamond gels produced the smoothest surface. A 30-fluted carbide did not improve smoothness as used. The aluminum oxide point followed by aluminum oxide pastes was equivalent to finishing diamonds and gels for Dicor ceramic.
The projective Kerdock code

Certain nonlinear binary codes can be constructed as binary images of Z 4 -linear codes under the Gray map. Examples include the second-order Reed-Muller code and the Kerdock and Preparata codes. In this paper, we consider a new quaternary code which is an additive subcode of the Z 4 -linear Kerdock code. The Kerdock code is the direct sum of a one-dimensional quaternary code and the quaternary subcode examined in this paper. This paper calculates the weight distribution of the projective Kerdock code from which the weight distribution of the dual code can be computed. The dual code is a supercode of the quaternary Preparata code. The projective Kerdock code is used to construct a deterministic measurement matrix for compressed sensing. Numerical experiments are presented for sparse reconstruction using the LASSO that show improvement over random Gaussian matrices of the same size.
Fabrication and characterization of low temperature (<450 ◦ C) grown p-Ge/n-Si photodetectors for silicon based photonics

P–n hetero-junctions were fabricated by depositing p-Ge thin films on n-Si substrates using molecular beam epitaxy and electron-beam evaporation, with processing temperatures less than 450 ◦ C, to be compatible with back-end silicon processing. The surface preparation of the Si substrate prior to Ge deposition was found to significantly affect the crystallinity of the deposited Ge layers and, hence, the p–n photodetector diode characteristics. The quality of the deposited Ge layers was inferred both through electrical and optical measurements as well as through structural characterization, i.e. X-ray diffraction (XRD). Surface desorption treatments to remove adsorbed hydrogen, oxygen and hydrocarbons were attempted to improve the Si surface quality to increase the minority carrier diffusion lengths and minimize dark current densities. Hydrogen desorption treatment at 450 ◦ C prior to Ge deposition gave the best performance with diffusion lengths greater than 25 nm and dark currents of 0.3 mA/cm 2 . The observed performance from the p–n diodes is expected to be sufficient for fabricating
Surgical site infection after open reduction and internal fixation of tibial plateau fractures.

Objective The aim of this study was to identify risk factors for surgical site infections and to quantify the contribution of independent risk factors to the probability of developing infection after definitive fixation of tibial plateau fractures in adult patients.
The incorporation of glycerol into the glyceride-glycerol of fat cells isolated from chronically cold-exposed rats.

The rate of 2-14C-glycerol incorporation into the glyceride-glycerol moiety was measured in isolated fat cells from control rats maintained at 25 C and from animals chronically exposed to cold (5 C) for six to eight weeks. The rate of glycerol conversion (μM/μg DNA/30 min) was less in the cold-exposed rats, than in comparable controls (1.96±0.14 vs. 2.68±0.17). Very little glycerol was oxidized to CO2 or converted to fatty acids. In both groups of animals, the glyceride-glycerol formation was apparently stimulated by noradrenaline in the presence of glucose, but this incorporation does not significantly bias the estimation of lipolysis based upon glycerol release.