cssi/SciSciGPT-SciSciNet huggingface dataset:
Ecological drivers of variation in tool-use frequency across sea otter populations

Sea otters are well-known tool users, employing objects such as rocks or shells to break open hard-shelled invertebrate prey. However, little is known about how the frequency of tool use varies among sea otter populations and the factors that drive these differences. We examined 17 years of observational data on prey capture and tool use from 8 sea otter populations ranging from southern California to the Aleutian Islands in Alaska. There were significant differences in the diets of these populations as well as variation in the frequency of tool use. Sea otters at Amchitka Island, Alaska, used tools on less than 1% of dives that resulted in the capture of prey compared with approximately 16% in Monterey, California. The percentage of individuals in the population that used tools ranged from 10% to 93%. In all populations, marine snails and thick-shelled bivalves were most likely to be associated with tool use, whereas soft-bodied prey items such as worms and sea stars were the least likely. The probability that a tool would be used on a given prey type varied across populations. The morphology of the prey item being handled and the prevalence of various types of prey in local diets were major ecological drivers of tool use: together they accounted for about 64% of the variation in tool-use frequency among populations. The remaining variation may be related to changes in the relative costs and benefits to an individual otter of learning to use tools effectively under differing ecological circumstances.
The effects of low molecular weight dextran infusion in humans

Summary Five hundred ml. of low molecular weight dextran was administered to six normal human subjects and to two patients convalescing from mitral commissurotomy. Circulatory, ventilatory and acid-base data were obtained during right heart catheterization prior to and after infusion of the dextran solution. There were no significant differences between pre- and postinfusion measurements. This suggests that low molecular weight dextran produces effects in normal subjects similar to those of other blood volume expanders. Peripheral and central vascular resistances did not decrease.
Climate change impacts on extreme events in the United States: an uncertainty analysis

In this study, we analyze changes in extreme temperature and precipitation over the US in a 60-member ensemble simulation of the 21st century with the Massachusetts Institute of Technology (MIT) Integrated Global System Model–Community Atmosphere Model (IGSM-CAM). Four values of climate sensitivity, three emissions scenarios and five initial conditions are considered. The results show a general intensification and an increase in the frequency of extreme hot temperatures and extreme precipitation events over most of the US. Extreme cold temperatures are projected to decrease in intensity and frequency, especially over the northern parts of the US. This study displays a wide range of future changes in extreme events in the US, even simulated by a single climate model. Results clearly show that the choice of policy is the largest source of uncertainty in the magnitude of the changes. The impact of the climate sensitivity is largest for the unconstrained emissions scenario and the implementation of a stabilization scenario drastically reduces the changes in extremes, even for the highest climate sensitivity considered. Finally, simulations with different initial conditions show conspicuously different patterns and magnitudes of changes in extreme events, underlining the role of natural variability in projections of changes in extreme events.
Finite Element Modeling and Ray Tracing of Parabolic Trough Collectors for Evaluation of Optical Intercept Factors with Gravity Loading.

Predicting the structural and optical performance of concentrating solar power (CSP) collectors is critical to the design and performance of CSP systems. This paper presents a performance analysis which utilizes finite-element models and ray-tracing of a parabolic trough collector. The finite-element models were used to determine the impact of gravity loads on displacements and rotations of the facet surfaces, resulting in slope error distributions across the reflective surfaces. The geometry of the LUZ LS-2 parabolic trough collector was modeled in SolidWorks, and the effects of gravity on the reflective surfaces are analyzed using SolidWorks Simulation. The ideal mirror shape, along with the 90° and 0° positions (with gravity deformation) were evaluated for the LS-2. The ray-tracing programs APEX and ASAP are used to assess the impact of gravity deformations on optical performance. In the first part of the analysis, a comprehensive study is performed for the parabolic trough to evaluate a random slope error threshold (i.e., induced by manufacturing errors and assembly processes) above which additional slope errors caused by gravity sag decrease the intercept factor of the system. The optical performance of the deformed shape of the collector (in both positions) is analyzed with additional induced slope errors ranging from zero up to 1° (17.44 mrad). The intercept factor for different solar incident angles found from ray-tracing is then compared to empirical data to demonstrate if the simulations provide consistent answers with experimental data.© 2011 ASME
Design of a 4-MHz analog integrated CMOS transconductance-C bandpass filter

A continuous-time eighth-order fully integrated CMOS transconductance-C bandpass filter is presented for operation at 4 MHz with 800 kHz bandwidth and 0.5 dB pass-band ripple. A phase-locked loop for frequency tuning and four-point amplitude-locking loop for Q-factor tuning at the reflection zeros of the filter are implemented. The transfer characteristics were found to be essentially within specifications: less than 1-dB passband attenuation, 75-dB stopband attenuation and S/N ratio, and 0.5% harmonic distortion for 0.5-V/sub p-p/ signal were observed. Offset of the transconductances was internally controlled by an offset-control loop to less than 4 mV. A temperature-insensitive transconductance design and the noise characteristics of the filter building blocks are also discussed. >
Kinetics and mechanism of the polymerization of styrene–acrylonitrile in the presence of polybutadiene

The mechanism of free radical grafting of styrene–acrylonitrile with polybutadiene was studied. By assuming a copolymerization mechanism an equation that related the amount of homopolymer formed and its molecular weight to a reactivity ratio and the charged ratio of monomer to polydiene was derived. Polymerizations that contained a variety of ratios of monomer to polybutadiene, two different catalysts, and variable amounts of a mercaptan modifier were studied. The weight fraction of homopolymer and its molecular weight were determined by high-speed GPC. The results were analyzed by the new equation and all showed a constant value of the reactivity ratio, which strongly suggests that the mechanism of the grafting reaction is copolymerization. Evidence that suggests that none of the grafting is a result of a hydrogen abstraction mechanism is also presented.
Diagnosis and management of achalasia

Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research, derived from extensive review of the published literature. When data are not available that will withstand objective scrutiny, a recommendation may be made based on a consensus of experts. Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of choices in any health care problem, the physician should select the course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee. These guidelines are also approved by the governing boards of the American Gastroenterological Association and the American Society for Gastrointestinal Endoscopy. Expert opinion is solicited from the outset for the document. Guidelines are reviewed in depth by the committee, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time. The following guidelines are intended for adults and not for pediatric patients.
Philip E. Muehlenbeck (ed.), Religion and the Cold War: A Global Perspective (Nashville: Vanderbilt University Press, 2012), xxii + 314 pp.

Philip E. Muehlenbeck (ed.) (Nashville: Vanderbilt University Press, 2012), xxii +314 pp This collection of essays about the influence of religion on the Cold War examines a variety of issues, reli...
Organic synthesis in the coma of Comet Hale-Bopp?

Several organic molecules have now been detected in the coma of Hale–Bopp. These species may either emanate from the nucleus, or, as has been suggested by Bockelee–Morvan et al., could be synthesized in the coma. We have modelled the gas phase chemistry which occurred in the coma of Hale–Bopp, concentrating on the observed organic molecules HCOOH, HCOOCH3, HC3N and CH3CN. We find that gas phase chemical reactions are unable to synthesize the observed abundances of these molecules, so all these species are most probably present in the nuclear ice. We briefly discuss the implications of this result for the connection between cometary and interstellar ices.
Plumbing of hospital premises is a reservoir for opportunistically pathogenic microorganisms: a review

Several bacterial species that are natural inhabitants of potable water distribution system biofilms are opportunistic pathogens important to sensitive patients in healthcare facilities. Waterborne healthcare-associated infections (HAI) may occur during the many uses of potable water in the healthcare environment. Prevention of infection is made more challenging by lack of data on infection rate and gaps in understanding of the ecology, virulence, and infectious dose of these opportunistic pathogens. Some healthcare facilities have been successful in reducing infections by following current water safety guidelines. This review describes several infections, and remediation steps that have been implemented to reduce waterborne HAIs.
Relationship of carcinogenicity and cellular proliferation induced by mutagenic noncarcinogens vs carcinogens. III. Organophosphate pesticides vs tris(2,3-dibromopropyl)phosphate.

Abstract Relationship of Carcinogenicity and Cellular Proliferation Induced by Mutagenic Noncarcinogens vs Carcinogens. III. Organophosphate Pesticides vs Tris(2,3-dibromopropyl)phosphate. Cunningham, M. L., Elwell, M. R., and Matthews, H. B. (1994). Fundam. Appl. Toxicol. 23, 363-369. Our laboratory has been examining the mechanisms whereby chemicals produce mutagenicity in short-term in vitro assays yet fail to produce carcinogenesis in 2-year rodent bioassays. Previous studies indicated that some mutagenic hepatocarcinogens increased cell proliferation in the target organ, the liver, while other structurally related mutagens that were noncarcinogenic failed to do so. We demonstrate in this report that another mutagenic carcinogen, tris(2,3-dibromopropyl phosphate), increased cell proliferation that was localized in the outer medulla of the kidney. This was also the target site for carcinogenesis in a 2-year bioassay and is another example of the association between chemically induced cell proliferation and carcinogenesis. This study also reports the absence of increased cell proliferation in the liver or kidney after exposure in the diet to the mutagenic organophosphate insecticides dimethoate, dioxathion, and dichlorvos following dietary exposure for 2 weeks at the same dose levels and routes of exposure that did not increase the tumor incidence in either organ in 2-year carcinogenesis assays. The present studies support the tenet that chemically induced cell proliferation may be a necessary prerequisite for chemical carcinogenesis, since in rat liver and kidney there was neither cell proliferation after 2 weeks nor tumor development after 2 years dietary exposure to the mutagenic organophosphate insecticides dimethoate, dioxathion, and dichlorvos.
The Depiction of Illness and Related Matters in Two Top-Ranked Primetime Network Medical Dramas in the United States: A Content Analysis

The effectiveness of entertainment-education is evidenced in previous research; nevertheless, content analytic research on the health content in such programs has been relatively meager in comparison to the large amount of content analyses of health content in news or ads in print media or on television. To address this issue, the current study content analyzed the portrayals of illnesses and related matters in 127 episodes aired from 2000 to 2007 of two top-ranked television medical dramas in the United States (Grey's Anatomy and ER). Results indicated that the two shows portrayed a wide range of illnesses and diseases, with injury, cardiovascular disease, and cancer being the top three most frequently portrayed. Moreover, equal numbers of men and women patient characters were portrayed, Caucasians and African Americans were the top two portrayed races, and the elderly were underrepresented. Last, the shows framed illness and health mainly from a medical perspective in references to the illness's causes, diagnosis, treatment, and prevention. Theoretical and practical implications are discussed.
Aquatic insects as environmental monitors of trace metal contamination: Red River, New Mexico

Discontinuous sampling of water for toxic chemicals is unreliable in lotic ecosystems or in systems subjected to sporadic discharges. Such sampling either fails to detect the contaminants or seriously underestimates their concentrations. This study explored the use of resident aquatic insects as biomonitors of trace metal contamination in a river subjected to episodic spills of Mo mill tailings. Aquatic insects at sites downstream from the mill accumulated more Mo and Cu than upstream insects. Due to a prolonged shutdown at the mine, no tailings spills were recorded during this study and Mo and Cu levels in water and bottom sediments declined to near background levels. However, concentrations of these metals in insects declined only slightly. This study indicates that aquatic insects are useful biomonitors of trace metal contamination in an intermittently impacted system. Reduction of elevated trace metal concentrations from the insects occurred at a slower rate than from the non-living components of the river ecosystem thereby facilitating detection of the spills.
Inhibitory Effects of Oxyradicals on Surfactant Function: Utilizing in Vitro Fenton Reaction

The inhibitory effects of reactive oxygen species (ROS) on the surface tension-lowering abilities of three surfactants were compared: natural lung surfactant (NLS), KL4 surfactant containing synthetic peptide resembling the hydrophobic/hydrophilic domains of SP-B in an aqueous dispersion of phospholipids, and Survanta (SUR) containing SP-B and SP-C. The inhibitory concentrations of Fenton reactants (i.e. 0.65 mM FeCl2, 0.65 mM EDTA, 30 mM H2O2), deduced from dose-response plots of FeCl2 on minimum surface tension (MST) of SUR, were used to assess the Fenton effect on biophysical properties of various surfactants. Neither H2O2 (30 mM) nor FeCl2 with EDTA (both 0.65 mM) alone affected surfactant function, but when mixed together significantly increased (p < 0.01) the MST of SUR compared with KL4 (p < 0.05) in a FeCl2 concentration-dependent manner. This effect on NLS was not significant (p = 0.05) at similar phospholipid concentrations. Also, the range of increases in surface adsorption in mN/m at equilibrium surface tension (EST) was 27-40 for SUR, 36-44 for KL4, and 24-25 for NLS. We speculate that the presence of SP-A and the catalase content in NLS may have protective effects on inactivation of NLS by ROS. We conclude that the in vitro Fenton effect could be a valuable test system for comparing the inactivation range of surfactants by oxyradicals.
The Luria-Nebraska Neuropsychological Battery-Children's Revision: Discrimination between Learning-Disabled and Slow-Learner Children:

The ability of the Luria-Nebraska Neuropsychological Battery-Children's Revision (LNNB-CR) to discriminate learning disabled (N = 27) and slow-learner (N = 14) students and to discriminate these gr...
Brief paper: Adaptive motion coordination: Using relative velocity feedback to track a reference velocity

We study a coordination problem where the objective is to steer a group of agents to a formation that translates with a prescribed reference velocity. In Bai et al. [Bai, H., Arcak, M., & Wen, J. (2008). Adaptive design for reference velocity recovery in motion coordination. Systems and Control Letters, 57(8), 602-610.] we considered the situation where the reference velocity information is available only to a leader, and developed a decentralized adaptive design that uses relative position feedback. Although Bai et al. (please see above reference) guaranteed the desired formation, it did not ensure tracking of the reference velocity with the exception of special cases. We now propose a new adaptive redesign that guarantees tracking of the reference velocity by incorporating relative velocity feedback in addition to relative position feedback.
Insulin like growth factor-binding protein-1 as a marker for hyperinsulinemia in obese menopausal women.

Hyperinsulinemia, a manifestation of insulin resistance, precursor of non-insulin dependent diabetes mellitus (NIDDM) and the hallmark of Syndrome X was assessed in 27 obese post-menopausal women. Insulin-like growth factor binding protein-1 (IGFBP-1), which had been shown previously to correlate inversely with insulin in animal and human studies, was evaluated as a diagnostic marker for abnormal glucose stimulated area under the curve (AUC) insulin (defined a priori as > or = 100 microU/ml). We performed analysis of variance and logistic regression to assess IGFBP-1 and other study covariates, including body mass index, blood pressure, lipids and measures of glucose and insulin in hyperinsulinemic vs. normal women and evaluated performance characteristics (sensitivity, specificity, positive and negative predictive values and accuracy rates). The mean IGFBP-1 was 6.1 ng/ml (95% confidence interval (CI) 3.1 to 8.9) for the hyper-insulinemic women compared to 33.5 ng/ml (CI 15.8 to 51.2) for normal women (P = .0027). At a cutoff point of 15ng/ml, which was selected to correspond to the lower 95% confidence limit for the normal study population, IGFBP-1 was abnormal in all 13 women with hyperinsulinemia and 4 women with normal insulin levels (sensitivity 100%, specificity 69%; positive predictive value 76%, negative predictive value 100%, diagnostic accuracy rate 85%). Logistic regression models indicated that, of all study covariates, IGFBP-1 was the best predictor variable for AUC-insulin as a binary dependent variable. These results suggest that IGFBP-1 may be a simple serum marker for hyperinsulinemia in a subpopulation of obese menopausal women.
EPDM based double slope triangular enclosure solar collector: a novel approach.

Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial and operating costs together with ease of maintainability. As domestic heating requires only nominal heating temperature to the range of 60–90°C, therefore replacing nickel coated copper pipes with any cheap alternate can drastically reduce the cost of solar heater. We have proposed a new concept which utilizes double slope triangular chamber with EPDM based synthetic rubber pipes. This has reduced the initial and operating costs substantially. A detailed analytical study was carried out to design a novel solar heater. On the basis of analytical design, a prototype was manufactured. Results obtained from the experiments were found to be in good agreement with the analytical study. A maximum error of 10% was recorded at noon. However, results show that error is less than 5% in early and late hours.
Sumatriptan (ImitrexR) Transport by the Human Placenta

AbstractSumatriptan (ImitrexR), a selective 5-hydroxytryptamine receptor agonist, has been found to be of therapeutic benefit in the acute management of migraine. There is no information on the transfer of this agent across the human placenta. Accordingly, the current study assessed the transport of this drug across the normal term human placenta, using the isolated perfused single cotyledon technique.We found that only about 15% of a single dose of the agent placed in the maternal reservoir crossed into the fetal compartment over 4 hr. Given the average elimination half-life of 2 hr for sumatriptan, it is evident that only very small amounts of the agent will cross from mother to fetus after single doses of imitrexR. Only the parent drug entered the fetal compartment. Metabolites were not detected in the perfusates, but there was evidence of some metabolism of sumatriptan in the placenta. The nature of the metabolites has not been determined. The mechanism of transfer of the drug across the placenta is p...
Deterministic selection of pilot tones for compressive estimation of MIMO-OFDM channels

This paper addresses the problem of channel estimation in multiple-input and multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems for the case when the underlying multipath channel is approximately sparse in the angle-delay domain. To this end, an algorithm for deterministic selection of pilot tones over which (either random or deterministic) training vectors can be transmitted is proposed. In addition, conditions are derived for the minimum number of pilot tones needed by the proposed algorithm to ensure reliable estimation of the underlying channel using reconstruction methods from the compressed sensing literature. Finally, effectiveness of the proposed algorithm is demonstrated through numerical experiments.
Application of Focal Conflict Theory to Psychoeducational Groups: Implications for Process, Content, and Leadership

Group psychoeducation is a common group type used for a range of purposes. The literature presents balancing content and process as a challenge for psychoeducational group leaders. While the significance of group psychoeducation is supported, practitioners are given little direction for addressing process in these groups. Focal Conflict Theory (FCT) is a model for conceptualizing and intervening in group process that has been applied to therapy and work groups. This article presents the challenges of psychoeducational groups, describes FCT, and discusses its application to psychoeducational groups using case examples. Implications for leaders of psychoeducation groups are discussed.
The impact of health literacy and socioeconomic status on asthma disparities.

Objective. Racial/ethnic disparities have been well documented in asthma. While socioeconomic status (SES) has been repeatedly implicated as a root cause, the role of limited health literacy has not been extensively studied. The purpose of this study was to examine the independent contributions of SES and health literacy in explaining asthma disparities. Methods. A cohort study was conducted in a Chicago-based sample of 353 adults aged 18–40 years with persistent asthma from 2004 to 2007. Health literacy, SES, and asthma outcomes including disease control, quality of life, emergency department visits, and hospitalizations were assessed in person at baseline, and asthma outcomes were measured every 3 months for 2 years by phone. Multivariate models were used to assess racial/ethnic disparities in asthma outcomes and the effect of health literacy and SES on these estimates. Results. Compared with White participants, African American adults fared significantly worse in all asthma outcomes (p < .05) and Latin...
The putative aminophospholipid translocases, DNF1 and DNF2, are not required for 7-nitrobenz-2-oxa-1,3-diazol-4-yl-phosphatidylserine flip across the plasma membrane of Saccharomyces cerevisiae.

The regulation of phosphatidylserine (PS) distribution across the plasma membrane of eukaryotic cells has been implicated in numerous cell functions (e.g. apoptosis and coagulation). In a recent study, fluorescent phospholipids labeled in the acyl chain with 7-nitrobenz-2-oxa-1, 3-diazol-4-yl (NBD) were used to identify two members of the P4 subfamily of P-type ATPases, Dnf1p and Dnf2p, that are necessary for the inward-directed transport of phospholipids across the plasma membrane (flip) of yeast (Pomorski, T., Lombardi, R., Riezman, H., Devaux, P. F., Van Meer, G., and Holthuis, J. C. (2003) Mol. Biol. Cell14, 1240-1254). Herein, we present evidence that the flip of NBD-labeled PS (NBD-PS) across the plasma membrane does not require the expression of Dnf1p or Dnf2p. In strains in which DNF1 and DNF2 are both deleted, the flip of NBD-PS is increased ∼2-fold over that of the isogenic parent strain, whereas the flip of NBD-labeled phosphatidylcholine and NBD-labeled phosphatidylethanolamine are reduced to ∼20 and ∼50%, respectively. The mechanism responsible for NBD-PS flip is similar to that for NBD-labeled phosphatidylcholine and NBD-labeled phosphatidylethanolamine in its dependence on cellular ATP and the plasma membrane proton electrochemical gradient, as well as its regulation by the transcription factors Pdr1p and Pdr3p. Based on the observation that deletion or inactivation of all four members of the DRS2/DNF essential subfamily of P-type ATPases does not affect NBD-PS flip, we conclude that the activity reflected by NBD-PS internalization is not the essential function of the DRS2/DNF subfamily of P-type ATPases.
Protein synthesis as an early response to fertilization of the sea urchin egg: A model

Abstract We have developed a quantitative computer model which simulates the rise in protein synthesis resulting from the fertilization of the sea urchin egg. The model predicts the kinetics of incorporation of radioactively labeled amino acids into proteins for the experimental situation in which the amino acid pool is labeled prior to fertilization. The computer model is used to examine the impact of changes in the values of major parameters such as the time of initiation of protein synthesis, the rate at which mRNA is unmasked, the ribosome transit time, and the rate of depletion of the labeled amino acid pool on the kinetics of amino acid incorporation. When experimentally determined values for these parameters are used the model predicts kinetics which closely approximate the kinetics actually observed in newly fertilized eggs. We suggest that the rate at which mRNA is made available for translation and a change in the elongation rate following fertilization control the rise in protein synthesis, and that both of these processes are initiated within 0–2 min following the initial fertilization event.
Adriamycin-induced increase in serum aldosterone levels: effects in riboflavin-sufficient and riboflavin-deficient rats.

Previous studies in rats have demonstrated that 1) aldosterone enhances biosynthesis of renal flavin coenzymes; 2) riboflavin analogs inhibit the synthesis of aldosterone; and 3) adriamycin inhibits flavin coenzyme biosynthesis. In their entirety, these findings suggest that both diminished flavin coenzyme biosynthesis induced by adriamycin and a dietary riboflavin deficiency would result in decreased formation of aldosterone. The present study examined the effects of adriamycin treatment on serum aldosterone in rats consuming either a diet adequate in riboflavin or a riboflavin-deficient diet. Groups of rats fed specially prepared diets were injected for 3 days with adriamycin (cumulative dose range, 6-24 mg/kg BW). Pair-fed controls were given saline. After death, adrenal glands were excised, and blood samples were analyzed for aldosterone levels. No changes in adrenal weights or protein and potassium concentrations were observed after adriamycin treatment. In contrast to initial predictions, in ribofla...
The association between allergies and cancer: what is currently known?

Objective To provide an overview of what is currently known about the relationship between allergies and cancer. Data Sources Publications were selected from a systematic review of the English-language literature from established databases (eg, MEDLINE, EBSCO) and the references of materials identified through these databases. Study Selection Publications assessing the association between asthma, hay fever, or other allergy-related diseases and cancer were included in this review. Results Individuals with any type of allergy have a decreased risk for cancer (compared with the general population), including glioma, colorectal cancer, cancer of the larynx, non-Hodgkin lymphoma, cancer of the esophagus, oral cancer, pancreatic cancer, stomach cancer, and uterine body cancer. However, an increased risk for bladder cancer, lymphoma, myeloma, and prostate cancer exists among those with allergies. Studies that involve breast cancer, leukemia, lung cancer, melanoma, and thyroid cancer have shown no association or conflicting results related to allergies. More research is needed before conclusions can be made about the relation between allergies and Kaposi sarcoma, liver cancer, and cancer of the ovaries. Conclusions The association between allergies and cancer is site specific. Further research is needed to verify these results and to determine why such associations exist.
Semiparametric maximum likelihood for nonlinear regression with measurement errors.

Summary. This article demonstrates semiparametric maximum likelihood estimation of a nonlinear growth model for fish lengths using imprecisely measured ages. Data on the species corvina reina, found in the Gulf of Nicoya, Costa Rica, consist of lengths and imprecise ages for 168 fish and precise ages for a subset of 16 fish. The statistical problem may therefore be classified as nonlinear errors-in-variables regression with internal validation data. Inferential techniques are based on ideas extracted from several previous works on semiparametric maximum likelihood for errors-in-variables problems. The illustration of the example clarifies practical aspects of the associated computational, inferential, and data analytic techniques.
Methods for in situ visualization and assay of sulfurtransferases.

Abstract The dansyl derivative 5-dimethylamino-1-naphthalene thiosulfonate (DANTS) can serve as a sulfane sulfur-donor substrate for several of the sulfurtransferases, the reaction being dependent on the acceptor substrates supplied. Enzymatic cleavage of the sulfur-sulfur bond of DANTS releases the intrinsic fluorescence of the molecule, with an emission maximum of 500–510 nm (excitation at 325 nm). This process permits selective visualization of active sulfurtransferase enzymes separated in nondenaturing polyacrylamide gels, even from impure preparations. This technique was used to locate rhodanese (thiosulfate: cyanide sulfurtransferase, EC 2.8.1.1), thiosulfate reductase (EC unassigned), and a recently isolated prokaryotic enzyme that has been called sulfane sulfurtransferase. In addition, a refinement of the thiosulfate reductase assay technique is reported.
Theoretical and Experimental Investigation of an Intensity-Demodulated Fiber-Ring-Laser Ultrasonic Sensor System

We theoretically and experimentally investigate the performance of an ultrasound detection system based on a fiber ring laser (FRL) whose cavity includes a pair of fiber Bragg gratings. The ultrasonic detection is achieved by the FRL power variations in response to the ultrasound-induced cold-cavity loss modulation of the FRL. The effects of key FRL parameters, including pump power, laser cold-cavity loss, and laser cavity length, on the system signal-to-noise ratio (SNR) performance have been investigated. It is found that the maximum SNR is achieved when the frequency of the ultrasound is the same as that of the FRL relaxation oscillation (RO). Harmonic generations are more prominent when the ultrasonic frequency is at the RO frequency and highly dependent on the strength of the ultrasonic signal. The analysis provides a useful tool for the understanding and optimization of such ultrasonic sensor systems.
Understanding how organizations affect the civic engagement of adolescent participants

This chapter examines what we know about the predictors of civic engagement, the required elements for adults to be civically engaged, and the role that adolescent extracurricular activities play in creating civically engaged adults.
The control of cathodoluminescence in dolomite by iron and manganese

Variations in the cathodoluminescent properties of carbonates are usually attributed to differing proportions of manganese (Mn2+) as the most important activator, and iron (Fe2+) as the main inhibitor of luminescence. Interactions between manganese and iron concentrations and the luminescent properties of dolomite are demonstrated by petrographic and chemical analyses of 86 samples of dolomite representing a range of depositional environments and ages (Cambrian to Cretaceous) and a wide geographical distribution (North America and Europe). Iron and manganese are positively correlated in the dolomites, with the former showing a greater range of variation. Very small amounts of manganese are sufficient to activate the luminescence and as little as 100 ppm Mn2+ is present in highly luminescing samples. The intensity of luminescence is not proportional to the manganese concentration. Iron begins to quench luminescence as its concentration reaches 10,000 ppm. Above that level, luminescence is rapidly lost and total extinction occurs among samples containing more than 15,000 ppm Fe2+, regardless of the manganese concentration.
Photodegradation of Tryptophan Residues and Attenuation of Molecular Chaperone Activity in α-Crystallin Are Correlated

Abstract The major eye-lens protein α-crystallin is known to possess a remarkable sequence homology to the low molecular weight heat-shock proteins and has been shown to protect several proteins against thermally induced aggregation. In this work we demonstrate that the rapid aggregation of rabbit muscle phosphoglycerate kinase during incubation at 52°C is completely inhibited in presence of 1/3 moles α-crystallin monomer per mole enzyme. Upon irradiation by UV light, tryptophan fluorescence intensity of α-crystallin declines, reflecting the destruction of these residues. A remarkable correlation is revealed between the reduction in α-crystallin fluorescence during UV-irradiation and the loss of its ability to protect phosphoglycerate kinase against aggregation. Since a loss of tryptophan fluorescence in intact eye lenses in vivo has been demonstrated to occur upon exposure to UV light, as well as during aging, it is proposed that the enhanced rate of lens opacification and cataract formation, as well as the increased levels of damaged lens proteins, which accumulate under these conditions, are the result of the gradual loss of the chaperone-protein efficacy of α-crystallin.
Analysis, simulation and visualization of 1D tapping via reduced dynamical models

Abstract A low-dimensional center-of-mass dynamical model is devised as a simplified means of approximately predicting some important aspects of the motion of a vertical column comprised of a large number of particles subjected to gravity and periodic vertical tapping. This model is investigated first as a continuous dynamical system using analytical, simulation and visualization techniques. Then, by employing an approach analogous to that used to approximate the dynamics of a bouncing ball on an oscillating flat plate, it is modeled as a discrete dynamical system and analyzed to determine bifurcations and transitions to chaotic motion along with other properties. The predictions of the analysis are then compared–primarily qualitatively–with visualization and simulation results of the reduced continuous model, and ultimately with simulations of the complete system dynamics.
Minor groove to major groove, an unusual DNA sequence dependent change in bend directionality by a distamycin dimer

DNA sequence-dependent conformational changes induced by the minor groove binder, distamycin, have been evaluated by polyacrylamide gel electrophoresis. The distamycin binding affinity, cooperativity, and stoichiometry with three target DNA sequences that have different sizes of alternating AT sites, ATAT, ATATA, and ATATAT, have been determined by mass spectrometry and surface plasmon resonance to help explain the conformational changes. The results show that distamycin binds strongly to and bends five or six AT base pair minor groove sites as a dimer with positive cooperativity, while it binds to ATAT as a weak, slightly anticooperative dimer. The bending direction was evaluated with an in phase A-tract reference sequence. Unlike other similar monomer minor groove binding compounds, such as netropsin, the distamycin dimer changes the directionality of the overall curvature away from the minor groove to the major groove. This distinct structural effect may allow designed distamycin derivatives to have se...
A derivation-first approach to teaching algorithms

A common approach to teaching algorithms involves describing algorithms first and then proving their correctness afterwards. In this article we advocate a "derivation-first" approach in which algorithms are "derived," either from basic concepts or from simpler algorithms, before they are proved correct. We demonstrate how a number of "classical" algorithms can be derived, providing students with a more intellectually satisfying experience, a deeper intuition into how algorithm design works, and connections between algorithms that can be useful in developing algorithms for other problems.
Improving intersection performance with left turn phase reservice strategies

Advanced signal operations offer practitioners an opportunity to reduce delay at their intersections at minimal cost by using features already included in their signal control software. One advanced operations technique is phase reservice and its associated feature conditional reservice. This research examines the impact of applying these techniques to the left turn at Hall Blvd. on 99W in Tigard, OR. Significant delay savings were seen for the left turn movement with an average delay reduction of more than 30 seconds at the cost of approximately 3 seconds increased delay for the opposing through movement. Intersection delay reduction was found to be dependent on the ratio of left turning vehicles to opposing through traffic.
Contrast of slightly complex patterns: computing the perceived contrast of Gabor patches

The local contrast in an image may be approximated by the contrast of a Gabor patch of varying phase and bandwidth. In a search for a metric for such local contrast, perceived (apparent) contrast, as indicated by matching of such patterns, were compared here to the physical contrast calculated by a number of methods. The 2 cycles/deg 1-octave Gabor patch stimuli of different phases were presented side by side separated by 4 degrees. During each session the subjects (n equals 5) were adapted to the average luminance, and four different contrast levels (0.1, 0.3, 0.6, and 0.8) were randomly interleaved. The task was repeated at four mean luminance levels between 0.75 and 37.5 cd/m2. The subject's task was to indicate which of the two patterns was lower in contrast. Equal apparent contrast was determined by fitting a psychometric function to the data from 40 to 70 presentations. There was no effect of mean luminance on the subjects settings. The matching results rejected the hypothesis that either the Michelson formula or the King-Smith & Kulikowski contrast (CKK equals (Lmax-Laverage)/Laverage) was used by the subjects to set the match. The use of the Nominal contrast (the Michelson contrast of the underlying sinusoid) as an estimate of apparent contrast could not be rejected. In a second experiment the apparent contrast of a 1-octave Gabor patch was matched to the apparent contrast of a 2-octave Gabor patch (of Nominal contrast of 0.1, 0.3, 0.6, 0.8) using the method of adjustment. The result of this experiment rejected the prediction of the Nominal contrast definition. The local band limited contrast measure (Peli, 1990), when used with the modifications suggested by Lubin (1995), as an estimate of apparent contrast could not be rejected by the results of either experiment. These results suggest that a computational contrast measure based on multi scale bandpass filtering is a better estimate of apparent perceived contrast than any of the other measures tested.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Antiviral Activity of Intranasally Applied Human Leukocyte Interferon

Previous studies in our laboratory have demonstrated that the development of antiviral activity of human leukocyte interferon (IF) in nasal epithelial cells is time and concentration dependent and that the loss of intranasally applied human leukocyte IF is rapid. The present studies compared the activity of IF applied intranasally either by nasal drops or by a saturated cotton pledget. Adult volunteers had IF applied to an area of nasal mucosa (2 by 2 cm 2 ) either by repeated nose drops or by a saturated cotton pledget that was applied to the nasal mucosa and left in place for 1 h. Nasal epithelial cells scraped from the area of application, as well as the control, untreated side of the same volunteers, were challenged with vesicular stomatitis virus. No significant reduction in mean virus yield was found in volunteers who received 80,000 U by nose drops. Significant reduction ( P
Patriarchy, the Taleban, and politics of public space in Afghanistan

Abstract This paper analyzes the extreme situation of Afghan women under the Taleban by casting a historical and sociological lens to highlight (a) the patriarchal nature of gender and social relations, deeply embedded in Afghanistan's traditional and fragmented ethnic-based society, and (b) the existence of a weak central state, which has been unable to implement modernizing programs and goals in the face of Afghanistan's tribal feudalism. A patriarchal social structure and the absence of a centralized and modernizing state, along with the problematical stance of the international (and feminist) community during the critical years of the 1980s and early 1990s, resulted in an extreme form of social exclusion: Afghan women were banned from participation and decision-making, and from the public space itself. The data and analysis are derived from the relevant secondary sources and the author's observations and interviews in Kabul in early 1989.
Emergency imaging discrepancy rates at a level 1 trauma center: identifying the most common on-call resident “misses”

The focus of our research is to identify the most frequently reported on-call discrepancies at our hospital by modality and level of resident training. Our intent is to identify specific areas of concern that may be amenable to improvement through initiation of dedicated resident training in the field of emergency radiology. Our study included 648 significant discrepancies from 193,722 studies ordered through the emergency department over a 7-year period. The overall discrepancy rates were calculated for each resident level of training and modality type. Significance was determined using χ2 testing with α = 0.05. The most common types of discrepancies were identified. The overall rate of reported discrepancies was low for all levels of training (0.23–0.42 %) with a small, but statistically significant, decrease in rate for the senior residents. Common categories of discrepancies for all residents included fractures on radiographs (XR) and computed tomography (CT), masses and hemorrhage on CT, and lung nodules and pulmonary infiltrates on radiographs. Specific discrepancies reported more frequently for new call-takers included phalangeal fractures on XR as well as white matter disease, hepatic lacerations, pyelonephritis, peritoneal fluid, lymphadenopathy, and pneumothoraces on CT. It is our recommendation that radiology resident training programs ensure that the common discrepancies illustrated herein are specifically addressed as part of a dedicated emergency radiology course.
Dissolution and deformation in fractured carbonates caused by flow of CO2-rich brine under reservoir conditions

Abstract Geometrical alteration in fractures, caused by mineral dissolution, changes the contact area between fracture surfaces and affects the mechanical strength of fractures. It is difficult to determine the influence of dissolution on fracture porosity and permeability given the competition between fracture opening due to dissolution and fracture closure caused by mechanical deformation. Therefore, simulating flow in fractured reservoirs during enhanced oil recovery and CO 2 sequestration, where local porosity changes may significantly alter permeability, remains a fundamental challenge. Here, we present results from experiments and numerical simulations that explore the influence of coupled geochemical alteration and mechanical deformation on calcium carbonate fracture geometry. We scan the fracture surfaces, before and after the flow experiments, using high-resolution optical profilometry to map changes in aperture fields. Flow of brine equilibrated with CO 2 at 60 °C and pore pressure of 14 MPa leads to significant dissolution in fractured calcium carbonate cores. The evolution of the dissolution process depends, to first order, on the dimensionless Damkohler number D a . We vary D a in experiments by changing the flow rate through fractured cores and observe a transition in dissolution behavior over the range of flow rates from 0.1 ml/min to 20 ml/min. At large D a (small flow rate), dissolution causes the formation of large-scale channels aligned with the fractures. At small D a (large flow rate), dissolution occurs more uniformly over the fracture surfaces. However, the area of contacting asperities, controlled by the significant mechanical stresses (28 MPa) and fracture surface roughness, constrains the spatial extent of the dissolution. We use the measured aperture fields as input to a single-species, reactive-transport model. Simulated Ca 2+ dissolution agrees with temporal evolution of measured Ca 2+ concentrations in outflow fluid. Comparison of the simulated dissolved aperture fields with measured aperture fields after flow-through shows qualitative agreement. We also use our reactive-transport model to explore the role of changing fluid properties and flow rates on dissolution and the resulting alteration of porosity and permeability beyond our experimental conditions. Our results emphasize the importance of length-scales in the coupled response of chemo-mechanical deformation in fractured reservoirs under varied stress and flow conditions.