cssi/SciSciGPT-SciSciNet huggingface dataset:
Using a Topological Descriptor to Investigate Structures of Virus Particles

An understanding of the three-dimensional structure of a biological macromolecular complex is essential to fully understand its function. A component tree is a topological and geometric image descriptor that captures information regarding the structure of an image based on the connected components determined by different grayness thresholds. We believe interactive visual exploration of component trees of the density maps of macromolecular complexes can yield much information about their structure. To illustrate how component trees can convey important structural information, we consider component trees of four recombinant procapsids of a bacteriophage cystovirus i¾?6, and show how differences between the component trees reflect the fact that each non-wild-type mutant of the procapsid has an incomplete set of constituent proteins.
Basic Software Tools: Machine-Independent Graphics

One of the best uses for a high-level language like Common LISP is in the rapid prototyping of window-based user interfaces, now an accepted part of the software development process. Common LISP is especially appropriate for developing user interfaces when augmented with one of the current object oriented programming (OOP) packages: Object Lisp, Common LISP object system (CLOS), or Portable Common Loops (PCL).
The impact of firm membership in an Independent System Operator (ISO) on production cost and cost efficiency in the generation sector of the U.S. electric utility industry

This paper examines how ISO membership impacts cost efficiency. Utilities joining ISOs can face more competition in selling electric power, possibly leading to lower profits, which can incentivize utilities to operate more cost efficiently to maintain a specified level of profits. The empirical model involves estimating a Probit model, then OLS regression, then a stochastic cost frontier. Using a 1992 to 2000 panel of 34 investor‐owned electric utilities, empirical results indicate that ISO membership contributed to higher production cost, lower cost efficiency, and ISO members subject to the 1990 Clean Air Act Amendments operated more cost efficiently than ISO members not subject to the Amendments.
Telemedicine in the Intensive Care Unit: Its Role in Emergencies and Disaster Management

Disasters and emergencies lead to an overburdened health care system after the event, so additional telemedicine support can improve patient outcomes. If telemedicine is going to become an integral part of disaster response, there needs to be improved preparation for the use of telemedicine technologies. Telemedicine can improve patient triage, monitoring, access to specialists, health care provider burnout, and disaster recovery. However, the evidence for telemedicine and tele-intensive care in the disaster setting is limited, and it should be further studied to identify situations in which it is the most clinically effective and cost-effective.
Reconsidering the “MR Unsafe” breast tissue expander with magnetic infusion port: A case report and literature review

Breast tissue expanders (TEs) with magnetic infusion ports are labeled "MR Unsafe." Therefore, patients with these implants are typically prevented from undergoing magnetic resonance imaging (MRI). We report a patient with a total submuscular breast TE who inadvertently underwent an MRI exam. She subsequently developed expander exposure, requiring explantation and autologous reconstruction. The safety profile of TEs with magnetic ports and the use of MRI in patients with these implants is surprisingly controversial. Therefore, we present our case report, a systematic literature review, and propose procedural guidelines to help ensure the safety of patients with TEs with magnetic ports that need to undergo MRI exams.
Modes of cannabis use: A secondary analysis of an intensive longitudinal natural history study.

Abstract Introduction There is a paucity of research on modes of cannabis use (e.g., joint vs. blunt), and further, little consensus on how to accurately assess both modes of use and route of administration. This secondary analysis used a longitudinal design with data collected daily to characterize mode of cannabis use. Methods 193 adult daily cannabis users who were considering quitting at some point enrolled in the study. No treatment was provided. Each day for 84 days, participants reported on mode of cannabis use (i.e., joints, blunts, pipes/vaporizer and food) using an interactive voice response system. We report on single and poly-use of modes across study days and weeks and examine characteristics associated with different modes of use. Results White participants were most likely to use pipes/vaporizer, with use on 57% of study days, while Black participants were most likely to use blunts with use on 53% of days. Thus, joint use was less common in both groups. Poly-use of different modes within the same week was very common (i.e., 56% of weeks among White participants and 60% of weeks in Black participants). Age, gender, race, cannabis dependence, presence of others during cannabis use, and alcohol use were associated with different modes of use. Conclusions The major limitation of this study was use of a convenience sample and lack of detailed data on vaporizer use. Joint use is no longer the most common mode of use in either White or Black participants and exclusive use of a single modality is uncommon.
Increase liquid oil production by huff-n-puff of produced gas in shale gas condensate reservoirs

Abstract Huge shale resources available and low gas price turn the oil operators’ activities to producing more liquid oil. The earlier studies from our research group and others show that huff-n-puff has the highest potential to improve oil recovery (IOR) in shale oil reservoirs, compared with common IOR methods of gas flooding and waterflooding. This paper is to extend the research to shale gas condensate reservoirs to evaluate the IOR potential. The simulation analysis approach is used. The simulation results and discussions in this paper show that huff-n-puff injection of produced gases can produce more liquid oil in gas condensate reservoirs than gas flooding or primary depletion. This result is verified by all the simulated cases with different reservoir and fluid properties and operation conditions. The advantages of huff-n-puff over gas flooding are the early response to gas injection, high drawdown pressure, oil saturation decrease near the wellbore by evaporation, and overcoming the pressure transport problem owing to ultra-low permeability. The advantages become more important when the initial reservoir pressure is close to the dew point pressure, or the bottom-hole flowing pressure is low. The effects of injected gas composition, cycle time and soak time during the huff-n-puff process are investigated. A simple economic analysis is also conducted.
Hydrogen-exchange kinetics studied through analysis of self-decoupling of nuclear magnetic resonance

Hydrogen exchange between solute and water molecules occurs across a wide range of timescales. Rapid hydrogen-exchange processes can effectively diminish 1H-15N scalar couplings. We demonstrate that the self-decoupling of 15N nuclear magnetic resonance can allow quantitative investigations of hydrogen exchange on a micro- to millisecond timescale, which is relatively difficult to analyze with other methods. Using a Liouvillian matrix incorporating hydrogen exchange as a mechanism for scalar relaxation, the hydrogen exchange rate can be determined from 15N NMR line shapes recorded with and without 1H decoupling. Self-decoupling offers a simple approach to analyze the kinetics of hydrogen exchange in a wide range of timescale.
Deep learning-enabled resolution enhancement of scanning electron microscopy images

We present a deep learning-based framework to perform single image super-resolution of SEM images. We experimentally demonstrated that this network can enhance the resolution of SEM images by two-fold, allowing for a reduction of the scanning time and electron dosage by four-fold without any significant loss of image quality. Using blindly tested regions of a gold-on-carbon resolution test target, we quantitatively and qualitatively confirmed the image enhancement achieved by the trained network. We believe that this technique has the potential to improve the SEM imaging process, particularly in cases where imaging throughput and minimizing beam damage are of utmost importance.
With Childhood Hemispherectomy, One Hemisphere Can Support—But is Suboptimal for—Word and Face Recognition

Abstract The left and right cerebral hemispheres are important for word and face recognition, respectively—a specialization that emerges over human development. But children who have undergone a hemispherectomy develop with only one hemisphere. The question is whether this preserved hemisphere, be it left or right, can support both word and face recognition. Here, a large sample of patients with childhood hemispherectomy and age-matched controls performed word- and face-matching tasks. Controls viewed stimuli either in one visual field (restricting initial processing to one hemisphere) or, like the patients, in central vision. Across word and face tasks, patients performed comparably to controls using primarily one hemisphere, but more poorly than controls viewing stimuli centrally with both hemispheres engaged. Additionally, patients showed deficits in low-level visual processing that may explain their word/face recognition deficits relative to controls. Altogether, the findings suggest that either hemisphere alone can support word and face recognition, albeit sub-optimally.
In vivo microscopic imaging for diagnosis of fibrotic interstitial lung disease using endobronchial optical coherence tomography

Early, accurate diagnosis of interstitial lung disease (ILD) is critical for clinical management and therapeutic decision-making, especially distinguishing idiopathic pulmonary fibrosis (IPF) from non-IPF ILD. Unfortunately, current diagnostic imaging methods are limited in resolution and surgical biopsy methods are invasive. In this study, we evaluate the accuracy of endobronchial optical coherence tomography (EB-OCT) as a low-risk method for in vivo ILD diagnosis in patients undergoing surgical biopsy. EB-OCT was able to distinguish diagnostic microanatomical features of IPF from non-IPF ILDs, independently compared against surgical biopsy. These findings support the potential of OCT as a minimally-invasive method for IPF diagnosis.
Open the Marriage to Save It: A Peer-to-Peer Savings & Payments Platform and Complementary Digital Euro Plan

Many units of government see a need for more inclusive money, payment, and retail banking systems for the generation, accumulation, and free transfer of spendable value among their constituents. Currently proliferating payments platforms, most provided by for-profit private-sector entities, exclude too many people, and extract too much value in the form of needless transaction charges and other rents, to be up to the task of efficiently affording this essential commercial and financial utility to full publics on reasonable terms. This document sketches a smart-device-accessible peer-to-peer (‘P2P’) platform – the ‘Digital Euro Platform’ – which, thanks to new payments technologies, can easily be put into place and administered by any unit of government, from city to nation to full European Monetary Union, with a view to supplying this indispensable productive, commercial and financial infrastructure to all of its constituents. Because a money is simply what ‘counts’ for purposes of value accounting within a payments architecture, moreover, the Platform will also enable EMU-approved euro-supplementation by value-capturing ‘complementary currencies’ in cash-poor Eurozone localities.
Low coronary flow relative to myocardial mass predicts heart failure in symptomatic hypertensive patients with no obstructive coronary artery disease.

AIMS The transition from hypertension to heart failure (HF) remains poorly understood. We hypothesized that insufficient perfusion to match global metabolic demand, reflected by a low ratio of myocardial blood flow to global myocardial mass, may be a HF risk marker. METHODS AND RESULTS A retrospective cohort (n = 346) of patients with hypertension who underwent clinical positron emission tomography (PET) myocardial perfusion imaging for chest pain and/or dyspnoea at Brigham and Women's Hospital (Boston, MA, USA) were studied. Patients without obstructive coronary artery disease by history or PET perfusion (summed stress score <3), HF, cardiomyopathy, or ejection fraction (EF) <40% were followed for HF hospitalization (primary outcome), all-cause death, and their composite. Myocardial blood flow, left ventricular (LV) mass, volumes, and EF were obtained from PET, and a 'flow/mass ratio' was determined as hyperaemic myocardial blood flow over LV mass indexed to body surface area. A lower flow/mass ratio was independently associated with larger end-diastolic (β = -0.44, P < 0.001) and end-systolic volume (β = -0.48, P < 0.001) and lower EF (β = 0.33, P < 0.001). A flow/mass ratio below the median was associated with an adjusted hazard ratio of 2.47 [95% confidence interval (CI) 1.24-4.93; P = 0.01] for HF hospitalization, 1.95 (95% CI 1.12-3.41; P = 0.02) for death, and 2.20 (95% CI 1.39-3.49; P < 0.001) for the composite. CONCLUSION An integrated physiological measure of insufficient myocardial perfusion to match global metabolic demand identifies subclinical hypertensive heart disease and elevated risk of HF and death in symptomatic patients with hypertension but without flow-limiting coronary artery disease.
Futures Matter: Creating Just Futures in This Age of Hyper-incarceration

What does it mean to teach and learn in this age of hyper-incarceration and the ongoing criminalization of multiply marginalized students and their families? And how can restorative justice be leve...
The Impact of Insecurity on Democracy and Trust in Institutions in Mexico

Analyses the impact of insecurity and crime victimization on support and satisfaction with democracy and trust in institutions in Mexico.
Global sourcing with China: the challenges faced by small US manufacturers

When the People's Republic of China joined the World Trade Organization in 2001, the US had to contend with an increasing economic trade deficit, as low-cost Chinese manufactured exports poured into its shores. China has since risen from the economic shambles following Mao's failed Cultural Revolution to become one of the world's superpowers, with its economy growing almost 10 percent per year. It has become a haven for multinational corporations and entrepreneurs who were enticed by the prospect of having few worries about minimum wages, pensions, benefits, unions, anti-pollution laws or worker safety regulations. In the face of the growing trade deficit trend between China and the US, American manufacturers should be asking what they can do to survive the tidal wave of Chinese imported goods. One option that merits consideration is global sourcing with Chinese businesses. Small US manufacturers must understand how to use off-shore capability to their own advantage and to the benefit of their customers. In this light, Sino-US macroeconomic forces as well as the legal and financial requirements of doing business with China must be understood. This article discusses the intense global competitive pressures that many small US manufacturers face and the issues and challenges they must confront in order to survive and even prosper. JEL classification: F02, O14, O34
Exploiting Hierarchical Structure for Efficient Formal Verification

Model checking is emerging as a practical tool for automated debugging of reactive systems such as embedded controllers and network protocols [9,11]. Since model checking is based on exhaustive state-space exploration, and the size of the state space of a design grows exponentially with the size of the description, scalability remains a challenge. The goal of our recent research has been to develop techniques for exploiting the modular design structure during model checking. Software design notations (e.g. Statecharts [10], Uml) provide rich constructs to facilitate modular descriptions. Instead of destroying this structure by compiling the descriptions into flat state-transition graphs, we are developing algorithms that are optimized for modular descriptions. In this talk, we summarize research concerning two different notions of hierarchy: architectural and behavioral.
Continuum Model of Medium with Cracks

A continuum approach to an elastic medium containing cracks is developed. A crack density tensor describing the averaged geometry of a crack array is introduced and used to study the anisotropy of an effective elastic response due to the presence of cracks. The resulting continuum model turns out to be orthotropic, which is in good agreement with the results given by the small concentration approach and the self-consistent method. Anisotropy of the transport properties (fluid permeability, electric- and heat conductivity) is also considered.
Human strand-specific mismatch repair occurs by a bidirectional mechanism similar to that of the bacterial reaction.

Nuclear extracts prepared from a HeLa cell line have been previously shown to support strand-specific repair of heteroduplex DNAs containing a site-specific, strand-specific incision (Holmes, J.J., Clark, S., and Modrich, P. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 5837-5841; Thomas, D.C., Roberts, J.D., and Kunkel, T.A. (1991) J. Biol. Chem. 266, 3744-3751). Further analysis of the substrate specificity of the reaction has shown that in addition to G-T, A-C, G-G, and C-C, nuclear extracts also recognize and correct in a strand-specific manner A-A, A-G, T-T, and C-T mismatches, with repair in each case being inhibited by aphidicolin. The rate of repair of a circular G-T heteroduplex was found to decrease monotonically with increasing separation between the mismatch and the strand break that targets repair, as viewed along the shorter path joining the two sites in the circular substrate. This decrease is independent of the polarity of the incised strand, suggesting that the human pathway of mismatch correction may possess a bidirectional excision capability similar to that of the Escherichia coli methyl-directed system. This possibility was confirmed by analysis of excision tracts associated with the reaction. Inhibition of DNA synthesis by aphidicolin or by omission of exogenous dNTPs leads to the mismatch-provoked formation of a single-strand gap that spans the shorter path between the strand break and the mismatch, irrespective of the polarity of the incised strand. Formation of these gaps, which extend from the site of the strand break to terminate at a number of discrete sites in the region 90 to 170 nucleotides beyond the mismatch, is therefore independent of the relative orientation of the two sites. Based on similar mismatch specificities and common features of mechanism, we have concluded that the human strand-specific mismatch repair system is functionally homologous to the bacterial methyl-directed pathway.
Platelet-derived growth factor (PDGF) stimulates PDGF receptor subunit dimerization and intersubunit trans-phosphorylation

Abstract High affinity binding of platelet-derived growth factor (PDGF) has been proposed to involve the interaction of the dimeric PDGF ligand with two receptor subunits, designated alpha and beta. We have cloned and expressed a human PDGF receptor cDNA which differs in sequence from the beta-subunit and which has the PDGF binding properties and monoclonal antibody recognition, predicted for the alpha-subunit. Scatchard analysis indicated that PDGF-AA and PDGF-AB bound to transfected alpha-subunits with affinities of Kd = 0.06 and 0.05 nM, respectively. PDGF-BB bound with a significantly lower affinity (Kd = 0.4 nM). Nevertheless, this affinity is still great enough to mediate substantial PDGF-BB binding at physiological concentrations and would be considered to be "high affinity." We have used wild-type and kinase-inactive human beta-subunits to show that PDGF binding promotes receptor subunit dimerization in intact cells. In addition, we found that PDGF stimulates tyrosine phosphorylation of the kinase-inactive beta-subunit when it is expressed with alpha-subunits. The kinase-inactive beta-subunits were phosphorylated at tyrosine 857 and 751, the major phosphorylation sites of the wild-type beta-subunit, indicating either that intra- and intermolecular phosphorylation occurs on the same sites, or that a significant fraction of receptor tyrosine phosphorylation is intermolecular.
Dorsal modified calcaneal plate for extensive midfoot arthrodesis.

Background: Extensive midfoot fusions can be challenging because of bone loss, deformity, and soft tissue anatomy. Several options have been advocated, including multiple screw fixation, medial pla...
Factors Associated With Recent and Discontinued Alcohol Use by Pregnant Adolescents

Abstract Purpose: To determine easily identifiable risk factors that differentiate pregnant adolescents who report recent (past 30 days) alcohol use and those who discontinue use by their first prenatal visit from those who deny consuming alcohol altogether. Methods: A structured interview was completed by 378 adolescents ≤17 years of age as part of standard care at our institution's adolescent obstetric clinic between July 7, 1992, and December 28, 1994. Using Chi-square or Student's t -tests, unique risk factors associated with recent or discontinued alcohol use in pregnancy were separately identified by comparing demographic, reproductive, behavioral, and environmental factors among recent users ( n = 43), discontinued users ( n = 48), and adolescents who denied ever using alcohol ( n = 108). Significant indicators were then entered into stepwise logistic regression analyses to determine the most efficient models for predicting alcohol use. Results: Partner alcohol use and use of alcohol during sexual activities were important risk factors for alcohol use by pregnant adolescents. Recent alcohol users were also more likely to be Mexican-American, to have quit school, and to report recent tobacco use, while adolescents who stopped using alcohol during pregnancy were significantly more likely to have witnessed or been a victim of or known a victim of violence. Conclusions: Screening at the first prenatal visit for these unique and easily assessed factors will help clinicians identify adolescents at greatest risk for alcohol use during pregnancy.
Valence-band mixing and continuum excitons in the excitonic model for coherent terahertz radiation from quantum wells

An excitonic model of terahertz radiation from quantum wells including the full angular momentum dependence of the valence band and exciton states and including continuum excitons is presented. The inclusion of multiple bound and continuum excitons leads to a complete model and better agreement with experimental data in the time and frequency domains. With the inclusion of the complete angular momentum dependence and continuum excitons, the model demonstrates the effect of mixing between light-hole bound excitons and the heavy-hole continuum on the generated terahertz radiation. A discontinuity in the applied field dependence of terahertz radiation frequency that appears in the experiments of Planken [Phys. Rev. Lett.69, 3800 (1992)] can be attributed to a Fano resonance between bound light-hole excitons and the heavy-hole continuum.
Optically Induced Electrokinetic Trapping and Sorting of Colloids

Recently, we have demonstrated electrothermal hydrodynamics with an external heating source of a highly focused 1,064 nm laser beam [1]. This phenomenon, when coupled with particle-electrode electrokinetic interactions, has led to the rapid and selective concentration of suspended colloids [2–6]. This technique, termed Rapid Electrokinetic Patterning (REP) was demonstrated without any additional surface modification or patterning of the electrodes. This dynamic, optically induced fluid and particle manipulation technique could be used for a variety of lab-on-a-chip applications. However, there are additional effects that have yet to be investigated that are important for a complete understanding of REP. This paper showcases experimental particle-particle behavior observations by varying particle diameter, electrode material, and preliminary results of varying fluid electrical conductivity.© 2010 ASME
The Genetic Basis of Addictive Disorders

Addictions are common, chronic, and relapsing diseases that develop through a multistep process. The impact of addictions on morbidity and mortality is high worldwide. Twin studies have shown that the heritability of addictions ranges from 0.39 (hallucinogens) to 0.72 (cocaine). Twin studies indicate that genes influence each stage from initiation to addiction, although the genetic determinants may differ. Addictions are by definition the result of gene × environment interaction. These disorders, which are in part volitional, in part inborn, and in part determined by environmental experience, pose the full range of medical, genetic, policy, and moral challenges. Gene discovery is being facilitated by a variety of powerful approaches, but is in its infancy. It is not surprising that the genes discovered so far act in a variety of ways: via altered metabolism of drug (the alcohol and nicotine metabolic gene variants), via altered function of a drug receptor (the nicotinic receptor, which may alter affinity for nicotine but as discussed may also alter circuitry of reward), and via general mechanisms of addiction (genes such as monoamine oxidase A and the serotonin transporter that modulate stress response, emotion, and behavioral control). Addiction medicine today benefits from genetic studies that buttress the case for a neurobiologic origin of addictive behavior, and some general information on familially transmitted propensity that can be used to guide prevention. A few well-validated, specific predictors such as OPRM1, ADH1B, ALDH2, CHRNA5, and CYP26 have been identified and can provide some specific guidance, for example, to understand alcohol-related flushing and upper GI cancer risk (ADH1B and AKLDH2), variation in nicotine metabolism (CYP26), and, potentially, naltrexone treatment response (OPRM1). However, the genetic predictors available are few in number and account for only a small portion of the genetic variance in liability, and have not been integrated into clinical nosology or care.
Injected periurethral collagen for postprostatectomy urinary incontinence: MR and CT appearance.

Background: Urinary incontinence, a disturbing complication of radical prostatectomy, is often treated with periurethral collagen injections to increase urethral closure and resistance to urinary outflow. Methods: Using magnetic resonance imaging and computed tomography, we studied the appearance of glutaraldehyde cross-lined bovine collagen endoscopically injected into the periurethral tissues in four men who developed urinary incontinence after radical prostatectomy. Collagen was also scanned in vitro to verify its magnetic resonance appearance. Results: Collagen deposits appear as well-circumscribed nodules of low to intermediate signal intensity on both T1- and T2-weighted images in the periurethral tissues or in the base of the subjacent penile bulb (base of corpus spongiosum). On contrast-enhanced computed tomography, collagen appears as a hypoattenuating nodular-filling defect within the penile bulb. Conclusion: These imaging characteristics should allow differentiation of collagen from locally recurrent prostate carcinoma and avoid inappropriate work-up of benign findings. RID="" ID="" Correspondence to: M. P. Banner
Understanding the final stages of wound contraction.

Much research has been undertaken to improve our understanding of the processes of wound contraction. This article, the second in a two-part series, focuses on granulation tissue modulation.
Intelligence and achievement of adult illiterates in a tutorial project: A preliminary analysis

Reports the results of preliminary analyses of intelligence and achievement in an adult tutorial project. Incarcerated adult illiterates volunteered to participate in a peer tutoring program wherein they received 27 hours of structured tutoring. Significant achievement was demonstrated in all areas. Achievement and gains in achievement were analyzed in relation to Verbal, Performance, and Full Scale IQ scores using four sets of analyses. Significant correlations were noted between IQ scores and achievement, but not gains in achievement. Gains in achievement were not significantly different among Ss at different Verbal, Performance and Full Scale IQ levels, nor were gains in achievement different between Ss who had a significant Verbal-Performance discrepancy and those who did not. Gains in achievement were not significantly different across subgroups categorized according to both IQ level and Verbal-Performance discrepancy.
Prostaglandin-Independent Anovulatory Mechanism of Indomethacin Action: Inhibition of Tumor Necrosis Factor α-Induced Sheep Ovarian Cell Apoptosis

Indomethacin, a nonsteroidal anti-inflammatory agent, is a potent inhibitor of ovulation in vertebrates. The presumptive obligate anovulatory mode of indomethacin action is via suppression of ovarian prostaglandin production. We report that a very high systemic dose of indomethacin (800 mg i.m.) is required to block ovulation in gonadotropin-treated anestrous ewes. A lower dose of indomethacin (200 mg), which negated the preovulatory rise in follicular prostaglandin (PGF(2alpha)) biosynthesis, did not prevent ovulation. Endothelial secretion of tumor necrosis factor (TNF)-alpha within the apical follicular wall (prospective site of rupture) was not altered by indomethacin; notwithstanding, the apoptosis (DNA-fragmentation)-inducing effect of TNF-alpha (a determinant of ovulatory stigma formation) was attenuated by 800 (but not 200) mg indomethacin. A suprapharmacological concentration of indomethacin also was necessary to protect ovarian surface epithelial cells from a (prostaglandin-independent) cytotoxic effect of TNF-alpha in vitro. It is concluded that indomethacin inhibits ovulation by anti-apoptotic mechanisms that can be dissociated from the paradigm of prostanoid down-regulation.
On controlling the maintenance of durable goods when contractual enforcement is costly

Abstract In a model of durable goods with costly maintenance enforcement contracts, monopolist may not control maintenance and perfectly competitive firms never will. This differs from the results of similar models with costless contractual enforcement.
Oxygen in the Outer Solar System

Several articles have appeared in this Journal regarding the chemical properties of oxygen and its importance on Earth for supporting biological processes. This commentary presents information regarding the discovery, formation, and importance of oxygen beyond Earth's biosphere, in particular the icy satellites of outer solar system, and shows that oxygen is likely to be important in the chemical evolution of such environments and is even of astrobiological interest.
Packed-bed reactor performance with immobilized lactase under thermal inactivation

Abstract Thermal inactivation of immobilized lactase has been studied in the presence of substrate and products. Modulation factors of thermal inactivation have been determined for lactose and galactose based on a two-stage series-type mechanism of inactivation. Galactose was a positive modulator of enzyme stability while the opposite occurred with lactose; the glucose effect was negligible. A model for packed-bed continuous reactor operation with chitin-immobilized lactase from Kluyveromyces marxianus var. marxianus was developed considering modulated thermal inactivation and appropriate kinetic expression for lactose hydrolysis. Experimental results were in good agreement with the model which was a far better representation of reactor performance than the conventional model not considering the effect of substrate and products on enzyme inactivation.
Perceptions of Adulthood among Anglo and Latino Parents

The transition to adulthood presupposes that a developing adolescent acquires a set of characteristics that enables him or her to perform expected adult behaviors. There is a gap in the literature in identifying these expected behaviors as they pertain to different cultural and racial groups. To fill this gap, parent-generated indicators of adulthood were studied, including the beliefs, behaviors, and attitudes that are either common or specific to Anglo and Latino parents. College students at an urban university in the Los Angeles area were recruited to enlist their parents to complete a questionnaire. Equal numbers from each ethnic group were surveyed. The results of this study indicate that Anglo participants defined adulthood in terms of independence significantly more often than Latino participants. Furthermore, Latino participants defined adulthood in terms of event-related markers, such as marriage, significantly more often than Anglo participants. This research points to the need to define adulthood in ways that reflect the ethnic diversity of the United States.
Thermal wave imaging of indented diamond coated WC

Photothermal radiometry has been used to obtain thermal wave images in the vicinity of indentations in WC{endash}6{percent}Ni coated with chemical vapor deposited (CVD) diamond. Features in the magnitude and phase of the thermal signal profile are consistent with a one dimensional thermal wave theory that assumes (i) an air gap extending well beyond the visibly observable indented region, and (ii) a thermal resistance interface between the diamond film and the substrate over the entire coated surface. The theory allows us to estimate the air gap thickness, which decreases as the distance from the indented region increases. Air gap variations of tens of nanometers appear to be easily detectable. {copyright} {ital 1997 Materials Research Society.}
Networks and Communal Autonomy as Practice: Health, Education, and Social Welfare in Lebanon

AbstractBuilding on ideas of networked governance and non-territorial autonomy, this article uses aspects of Lebanese public policy to show that significant functional communal autonomy can be achieved in the absence of coherent institutions designed to support it. In this way, the article argues that norms, notions of legitimacy, and behavioral practices are as important as institutional design in understanding communal autonomy. An overview of the Lebanese education, health, and welfare systems provides an understanding of how communal governance operates and interacts with the state across several policy areas. These policy areas are also used to explore issues of individual autonomy and state strength.
Hooked on Hes: A T-ALL of Addiction

Hes1 is a direct Notch1 target; however, its precise function is unclear. In this issue of Immunity, Wendorff et al. (2010) report that Hes1 regulates the number of T cell progenitors and has important functions in both the induction and maintenance of T cell leukemia.
Sexual Behavior as a Function of Stigma and Coping with Stigma Among People with HIV/AIDS in Rural New England

The relationship between coping with HIV/AIDS stigma and engaging in risky sexual behavior (i.e., inconsistent condom use) was examined in HIV-positive adults living in rural areas. Participants answered questions about their experiences with HIV/AIDS prejudice and discrimination (enacted stigma) and their perceptions of felt HIV/AIDS stigma (disclosure concerns, negative self-image, and concern with public attitudes). They were also asked about how they coped with HIV/AIDS stigma, and about their sexual activity during the past 90 days. We hypothesized that using disengagement coping to manage the stress of HIV/AIDS stigma would be related to risky sexual behavior. Multinomial logistic regression results showed that using disengagement coping (avoidance, denial, and wishful thinking) coupled with high levels of enacted stigma was associated with less risky rather than more risky sexual behavior. That is, disengagement coping coupled with high stigma increased the odds of not having vaginal or anal sex versus inconsistently using condoms. Implications for people with HIV/AIDS who use disengagement coping to manage stress to deal with HIV/AIDS stigma are discussed.
Taking the next step: a systematic review and meta-analysis of physical activity and behavior change interventions in recent post-treatment breast cancer survivors

Research has shown that recent post-treatment breast cancer survivors face significant challenges around physical activity as they transition to recovery. This review examined randomized controlled trials targeting physical activity behavior change in breast cancer survivors <5 years post-treatment and described (1) characteristics of interventions for breast cancer survivors as well as (2) effect size estimates for these studies. A systematic search was conducted following PRISMA guidelines with Medline, PubMed, PsycINFO, CINAHL, and Scopus databases. Data were abstracted for primary intervention strategies and other details (e.g., setting, duration, theory use). A subgroup analysis was conducted to assess intensity of exercise supervision/monitoring and intervention effectiveness. The search produced 14 unique behavior intervention trials from the US and abroad published 2005-2013. The mean sample size was 153 participants per study. All interventions included moderate-intensity activities plus various behavioral change strategies. Most interventions were partially or entirely home based. The overall standardized mean difference was 0.47 (0.23, 0.67) with p < 0.001. Most interventions were effective in producing short-term behavior changes in physical activity, but varied greatly relative to intervention strategies and intensity of supervision/monitoring. Highly structured interventions tended to produce larger behavior change effects overall, but many larger effect sizes came from interventions supported by phone counseling or e-mail. We observed that 'more' may not be better in terms of direct supervision/monitoring in physical activity behavior interventions. This may be important in exploring less resource-intensive options for effective behavior change strategies for recent post-treatment survivors.
Subtherapeutic Tetracycline Effects on Recovery Patterns of Calves After Salmonella typhimurium Challenge

Holstein calves were maintained on a subtherapeutic dose of chlortetracycline to determine if an oxytetracycline therapy, given after a Salmonella typhimurium challenge, would be compromised by the previous subtherapy. Two of the four groups of seven calves were maintained on a subtherapeutic amount of chlortetracycline. All calves then were challenged with Salmonella typhimurium, and with the onset of clinical symptoms one group with and one group without subtherapy were given a therapeutic dose of oxytetracycline. The two groups receiving a therapeutic dosage of oxytetracycline had the most quickly declining body temperatures and the highest average body weights post-challenge. Two calves died in the group receiving no antibiotic treatments, and one calf died in the group receiving only the subtherapeutic treatment. There were no differences in postchallenge body temperatures or body weight changes between subtherapeutic and nonsubtherapeutic groups of calves. The conclusion was that the subtherapeutic dosing of chlortetracycline did not affect the therapeutic treatment effects of oxytetracycline after a Salmonella typhimurium challenge.
TRIANGULAR SPECTRAL ELEMENTS FOR INCOMPRESSIBLE FLUID FLOW

In this paper we discuss the use of triangular elements in the spectral element method for direct simulation of incompressible flow. Triangles provide much greater geometric flexibility than quadrilateral elements and are better conditioned and more accurate when small angles arise. We employ a family of tensor product algorithms for triangles, allowing triangular elements to be handled with comparable arithmetic complexity to quadrilateral elements. The triangular discretizations are applied and validated on the Poisson equation. These discretizations are then applied to the incompressible Navier-Stokes equations and a laminar channel flow solution is given. These new triangular spectral elements can be combined with standard quadrilateral elements, yielding a general and flexible high order method for complex geometries in two dimensions. The natural generalization to tetrahedral elements in three dimensions will be described in a future work.
Identification of signals required for the insertion of heterologous genome segments into the reovirus genome

Abstract In cells simultaneously infected with any two of the three reovirus serotypes ST1, ST2, and ST3, up to 15% of the yields are intertypic reassortants that contain all possible combinations of parental genome segments. We have now found that not all genome segments in reassortants are wild type. In reassortants that possess more ST1 than ST3 genome segments, all ST1 genome segments appear to be wild type, but the incoming ST3 genome segments possess mutations that make them more similar to the ST1 genome segments that they replace. In reassortants resulting from crosses of the more distantly related ST3 and ST2 viruses that possess a majority of ST3 genome segments, all incoming ST2 genome segments are wild type, but the ST3 S4 genome segment possesses two mutations, G74 to A and G624 to A, that function as acceptance signals. Recognition of these signals has far-reaching implications for the construction of reoviruses with novel properties and functions.
Kinetic measurements on single-molecule disulfide bond cleavage.

We use single-molecule force clamp spectroscopy (SMFCS) to explore the reactivity of tris(2-carboxyethyl)phosphine (TCEP), 1, 4-dl-dithiothreitol (DTT) and hydrosulfide anion (HS−) on disulfide bonds within a mechanically stretched polypeptide. The single-bond level bimolecular nucleophilic substitution (SN2) events are recorded at a series of precisely controlled temperatures so that the Arrhenius kinetic parameters, that is, the height of the activation energy barrier (Ea) and the attempting frequency (A) of the chemical reactions, can be determined. The values of A are typically at the order of 107 M−1 s−1, which is far lower than that predicted by the transition-state theory, in which A is given by kBT/h and around 1012 M−1 s−1 at room temperature. Furthermore, Ea is derived to be 30−40 kJ/mol, which can be lowered by ∼6−8% with every 100 pN mechanical force applied. The correlation of the A and Ea with the molecular structures reveals that the relative magnitude of these two parameters cannot be simp...
Transport of Potassium Ions in the Rat's Intestine

THE transport of sodium ions across the epithelium of the small intestine of the rat seems to be an active process (for a review of the evidence see Durbin, Curran and Solomon1). This active transport of sodium ions may be responsible for the potential difference existing across the gut wall, the mucosal side of which is negative with respect to the serosal side. In the jejunum the amplitude of this potential reported in the literature ranges from about 8 mV (refs. 2, 3) to 12 mV (ref. 4); the potentials in the ileum are smaller3.
Automatic extraction of closed pixel clusters for target cueing in hyperspectral images

Traditional algorithms for automatic target cueing (ATC) in hyperspectral images, such as the RX algorithm, treat anomaly detection as a simple hypothesis testing problem. Each decision threshold gives rise to a different set of anomalous pixels. The clustered Rx algorithm generates target cues by grouping anomalous pixels into spatial clusters, and retaining only those clusters that satisfy target specific spatial constraints. It produces one set of target cues for each of several decision thresholds, and conservatively requires {Omicron}(K{sup 2}) operations per pixel, where K is the number of spectral bands (which varies from hundreds to thousands in hyperspectral images). A novel ATC algorithm, known as ''Pixel Cluster Cueing'' (PCC), is discussed. PCC groups pixels into clusters based on spectral similarity and spatial proximity, and then selects only those clusters that satisfy target-specific spatial constraints as target cues. PCC requires only {Omicron}(K) operations per pixel, and it produces only one set of target cues because it is not an anomaly detection algorithm, i.e., it does not use a decision threshold to classify individual pixels as anomalies. PCC is compared both computationally and statistically to the RX algorithm.
The Separation Theorem of Intuitionist Propositional Calculus

A standard set of axioms for the intuitionist propositional calculus is the following (we associate to the right, and use the convention that ⊃ binds less strongly than the other connectives).
Expert thinking in nursing practice: Implications for supporting expertise

The complexity of the art of expert nursing practice is an elusive phenomenon, which is difficult to articulate in concrete terms that can be translated into achieving quality patient care outcomes. The present study describes the findings of two hermeneutic (interpretive) studies on expert thinking that captured the holistic practice of expert clinicians. The findings from these studies provide insight into how expert practice can be administratively supported. These findings also have strong implications for strategies to facilitate the development of expertise in practice. In order to provide holistic care, nurses must spend time with their patients so that the particularities and meaning inherent in each unique patient situation can be understood. The art of expert thinking is a temporal and ethical activity, which needs to be supported and cultivated in a changing health-care delivery system.
Ukraine and the European Union: a perennial neighbour?

As ten new states are integrated into a family of democratic European nations, Ukraine, the second largest post‐Soviet state, is dismayed with the lack of progress in its own movement toward EU membership. While Kiev clamours to join the EU for both security and economic reasons, the Ukrainian government shies away from real reform at home. The paper examines dilemmas of Ukraine's ‘European choice’, focusing on the history of EU‐Ukraine relations, Kiev's strategy, mass perceptions, and the reasons behind the EU's unwillingness to start pre‐accession negotiations with the country. It concludes that the key obstacles in the way of Ukraine's Euro‐Atlantic integration are of Ukraine's own making and have to be addressed domestically. Ukraine's application for EU membership will not be favourably received until the country proves itself a democracy and reaches a higher level of economic development.
A random-walk model of human mortality and aging.

Abstract Consideration is made of the roles of certain types of state space and time scales for a random-walk model of individual physiological status change and death. Because the actual measurement of physiological variables omits many variables relevant to survival, we are forced to view this model as operating in a stochastic state space for a population of individuals where only the frequency distributions are deterministic. In this stochastic state space, under the assumption that the “history” of prior movement contains no additional information, the forward partial differential equation is obtained for the distribution of a population whose movement in the selected space is determined by the randomwalk equations. If the initial distribution of the population in the state space is normal, then certain assumptions about movement and mortality will operate to preserve normality thereafter. Under the assumption of normality, simultaneous ordinary differential equations can be derived from the forward partial differential equation defining the distribution function. Examination of the ordinary simultaneous differential equations shows how parameters for certain models of aging and mortality can be obtained.