cssi/SciSciGPT-SciSciNet huggingface dataset:
Reducing Network Vulnerability to Malicious Attacks

The underlying networks of many physical systems, including critical infrastructures, exhibit properties of complex networks such as scale-free properties. It is well-known that scale-free networks can tolerate random failures but show high vulnerabilities to targeted attacks, particularly compared to random networks of the same scale. In recent years many efforts have been made to reduce the vulnerability of such networks to targeted attacks by adding and/or rewiring links. However, to the best of our knowledge, the existing methods do not take attack patterns into consideration when determining how to improve or evaluate the resilience of a network. In this paper, we define an attack-dependent measure of vulnerability for networks and show that the problem of minimizing network vulnerability by adding a limited number of links while considering a potential attacks is NP-hard. Since the problem is intractable, we suggest a heuristic algorithm to reduces the vulnerability of a network with respect to specific attacks in polynomial time. By experimental results, we show that our approach outperforms the existing methods of network resiliency enhancement.
Aging and Sexing Human Remains from the Hopewell Site

Accurate aging and sexing of individual skeletons is fundamental to bioarchaeological analysis. Without these basic data, a mortuary site is limited in its potential to inform us about social organization, gender roles, the functions of ceremonial artifacts, and the demographic structure of the local community. The need for reliable age and sex information is particularly acute within Ohio Hopewell mound and earthwork sites, because extant collections of the individuals buried at the sites are spotty in coverage, putting a premium on the study of the individuals that are available. Most Ohio Hopewell sites were excavated in the late nineteenth and early twentieth centuries (Chapter 7), prior to the development of modern archaeological methods.
Finite Automata, Regular Languages and Type 3 Grammars

A finite automaton (fa), or finite state automaton (fsa), is an abstract computing device that receives a string of symbols as input, reads this string one symbol at a time from left to right, and after reading the last symbol halts and signifies either acceptance or rejection of the input. At any point in its computation a fa is in one of a finite number of states. The computations of a fa are directed by a “program,” which is a finite set of instructions for changing from state to state as the automaton reads input symbols. A computation always begins in a designated state, the initial state. There is also a specified set of final states; if the fa ends up in one of these after reading the input, it is accepted; otherwise, it is rejected.
Cell-Cell Interactions during Sea Urchin Morphogenesis

The dissociation of sea urchin embryos into a cell suspension and their subse-quent reaggregation provide a model system for studying cell-cell interactions during morphogenesis. Herbst (1900) first showed that sea urchin blastomeres could be dissociated with calcium-free seawater and—when returned to normal seawater—could reaggregate and develop into abnormal larvae. These ex-periments demonstrated that the hyaline layer surrounding the embryo holds the cells together and that calcium plays a role in cell adhesion. Giudice and Mutolo (1970) used this system to study the role of cell-cell interactions in the appearance of new metabolic patterns in development. This chapter reports on more recent work from our own and other laboratories using reaggregating cells to study cell adhesion and other cell-cell interactions during development. It also reports on our use of intact embryos to study the extracellular matrices and cell junctions on the external and internal surfaces during sea urchin morphogenesis.
Cities in Developing Countries: Fueled by Rural–Urban Migration, Lacking in Tenure Security, and Short of Affordable Housing

Abstract This chapter surveys and synthesizes existing research on urbanization and housing in developing countries. The goal is to provide a unified overview of the principal urban issues that arise in developing countries, painting a coherent picture that can provide a starting point for policy analysis. The chapter covers empirical work on rural–urban migration, theoretical research on migration and city-size determination, theoretical and empirical work on tenure security and squatting, and the issue of housing affordability.
2443. Searching for the Optimal Treatment Regimen for Metallo-β-Lactamase Producing Enterobacteriaceae: Aztreonam Plus Ceftazidime–Avibactam vs. Aztreonam Plus Meropenem–Vaborbactam

Background Pathogens harboring metallo-β-lactamase (MBL) enzymes pose a large threat to public health. Aztreonam (ATM) is not hydrolyzed by MBLs but is inactivated by other β-lactamases, which are often co-harbored in MBL-producers. Ceftazidime/avibactam (CAZ/AVI) and meropenem/vaborbactam (MER/VBR) are novel β-lactam/β-lactamase inhibitors (BL/BLI) with potent activity against serine β-lactamase producing Enterobacteriaceae. Combining ATM with BL/BLI agents may provide activity against Enterobacteriaceae producing serine and MBLs.
Sexual Assault Victimization and Perceptions of University Climate Among Bisexual Women

Sexual minority women are more likely to experience campus sexual assault than their heterosexual peers, and previous research suggests that bisexual women are especially at risk. The purpose of th...
Radiotherapy for recurrent intracranial epidermoid cysts without malignant transformation: a single-institution case series

Recurrent intracranial epidermoid cysts may be difficult to address surgically given their proximity to critical neurovascular structures of the skull base. There are emerging reports of using radiotherapy (RT) for the treatment of recurrent epidermoid cysts. Here, we report a case series of adjuvant fractionated external beam RT for recurrent intracranial epidermoid cysts. A single-institution review of all recurrent epidermoid cysts treated with adjuvant therapy between 2000 and 2017 was performed. Eight patients with recurrent epidermoid cysts who underwent adjuvant external beam RT were identified. Average age at initial diagnosis was 42.2 years, and median clinical follow-up after initial diagnosis and RT was 16.4 and 2.9 years, respectively. The median number of surgical resections prior to RT was 3 (range 2–5). Rationale for RT included multiple recurrent disease, rapid recurrence following prior resection, increased risk of further surgical morbidity, and patient preference. Median dose was 50.4 delivered in 1.8 Gy fractions (median 28 fractions). By the date of last follow-up, no patient has demonstrated progression, and there have been no cases of malignant degeneration. Adjuvant RT should be considered in the context of recurrent epidermoid cysts to decrease the likelihood of further recurrences.
Loss of a Foundation Species, Eastern Hemlock (Tsuga canadensis), May Lead to Biotic Homogenization of Fungal Communities and Altered Bacterial Abundance in the Forest Floor

Tsuga canadensis (Eastern Hemlock) is a key forest foundation species that is currently declining across the eastern US due to attack by exotic insect species, primarily Adelges tsugae (Hemlock Woolly Adelgid). In the northeastern US, declining Eastern Hemlock stands are typically replaced by fast-growing deciduous Betula lenta (Black Birch) trees, altering ecosystem processes and ecological communities. In this study, we used an approach that substituted space for time to explore how the forest floor's soil organic horizon, macrofungal communities, and bacterial abundance might be altered following Eastern Hemlock replacement by Black Birch. We compared intact, mature Eastern Hemlock forest plots at 2 sites in western Massachusetts to adjacent areas of vigorous regeneration of young Black Birch triggered by logging activity at the sites ∼25–30 years ago. Forest-floor soil organic horizons were significantly thicker under Eastern Hemlock forests and exhibited a higher carbon:nitrogen (C:N) ratio, suggesting slower decomposition and greater accumulation of organic material under Eastern Hemlock compared to deciduous Black Birch canopies. Macrofungal communities emerging from the forest floor did not differ strongly in morphospecies richness between Eastern Hemlock and Black Birch plots. However, a greater number of rare fungi taxa, defined in this study as those represented by a single observation, were detected in Eastern Hemlock plots, and the composition of Black Birch plots was more homogenized and less variable. The abundance of bacterial colony forming units (CFUs) in the soil organic horizon appeared to follow a seasonal pattern of variation between mature Eastern Hemlock versus young Black Birch plots; CFUs were most abundant in Black Birch soils in the fall, potentially tracking input of new deciduous leaf litter, whereas Eastern Hemlock plots had higher CFU counts in the summer. The results of this study suggest that forest-floor characteristics will be substantially altered by the impending loss of Eastern Hemlock, associated macrofungal communities may become simplified and homogenized, and the timing of peak bacterial abundance in the forest floor might be shifted to the fall.
Evaluation of Speech

The presentation of voice and laryngeal functions provides important clues for the diagnosis of a wide variety of speech disorders, but voice is just one component of the speech production system. When a person talks, the overall message is formulated and conveyed by complex integration of movements by the respiratory, phonatory, resonatory, and articulatory subsystems, as well as its prosodic components. This chapter focuses on the evaluation of speech for adults with dysarthria. The speech-language pathologist conducts a thorough, systematic examination of the speech production mechanism including observations at rest and during functional and maximal performance tasks. Auditory perceptual evaluation of speech is rated according to multiple parameters loosely arranged by subsystem. Clusters of speech characteristics, corroborated by results from the physical/functional examination, lead to the differential diagnosis among seven categories of dysarthria. Careful differential diagnosis can support the neurological workup of the patient and can lead to appropriate management plans. In addition to overall severity of the speech impairment, intelligibility is often considered a global rating of speech effectiveness. However, intelligibility is usually better than the overall impression of speech impairment and can grossly underestimate the patient’s disability and difficulties with participation in life’s activities. This chapter provides a glimpse into the complexity and depth of the motor speech evaluation and its implications for functional communication in adults with dysarthria. Each section discusses the rationale and interpretation of assessment procedures, current controversies, and recent innovations.
Cultural variations in understanding risks for delinquency among maltreated children from the perspectives of U.S. and Korean professionals

Abstract Cultural beliefs and values affect how professionals understand maltreated children who engage in delinquency and the appropriate societal responses to those youth. Guided by a sociocultural and developmental perspective, this study examined cultural variations in understanding risks for delinquency among maltreated children between the U.S. and South Korea. Cross-cultural analysis was conducted on data from the in-depth, semi-structured individual interviews with 21 U.S. and 20 Korean professionals serving various roles in the child welfare and juvenile justice systems. Professionals described common and culturally distinct risk factors. The common risk factors discussed by the U.S. and Korean professionals included: (1) psychosocial vulnerabilities of individual youth; (2) difficulties in parent-child relationship; and (3) systemic challenges to intervention. Yet their interpretations were culturally nuanced reflecting differences in social, cultural, and practice contexts: (1) external (U.S.) and internal (Korea) attribution to youth’s psychosocial vulnerabilities; (2) parents history of their own trauma (U.S.) and a lack of parental responsibilities (Korea) as underlying difficulties in the parent-child relationships; and (3) a lack of collaboration (U.S.) and a lack of accountability (Korea) across the child-serving systems as systemic challenges to intervention. Their discussion also revealed culturally unique risk factors: racial disparity (U.S.) and sociocultural justification for physical punishment (Korea). Implications are discussed for professionals, policy makers, and advocates to bring creative ideas for the implementation of culturally sensitive practices and policies in both countries.
Using Place-Based Jobs Policies to Help Distressed Communities

Place-based jobs policies seek to create jobs in particular local labor markets. Such policies include business incentives provided by state and local governments, which cost almost 50 billion USD [United States dollars] annually. The most persuasive rationale for these policies is that they can advance equity and efficiency by increasing long-term employment rates in distressed local labor markets. However, current incentives are not targeted at distressed areas. Furthermore, incentives have high costs per job created. Lower costs can be achieved by public services to business, such as manufacturing extension, customized job training, and infrastructure. Reforms to place-based jobs policies should focus on greater targeting of distressed areas and using more cost-effective policies. Such reforms could be achieved by state and local governments acting in their residents' interests or could be encouraged by federal interventions to cap incentives and provide aid to distressed areas.
OB Nest randomized controlled trial: a cost comparison of reduced visit compared to traditional prenatal care

Traditional prenatal care includes up to 13 in person office visits, and the cost of this care is not well-described. Alternative models are being explored to better meet the needs of patients and providers. OB Nest is a telemedicine-enhanced program with a reduced frequency of in-person prenatal visits. The cost implications of connected care services added to prenatal care packages are unclear. Using data from the OB Nest randomized, controlled trial we analyzed the provider and staff time associated with prenatal care in the traditional and OB Nest models. Fewer visits were required for OB Nest, but given the compensatory increase in connected care activity and supplies, the actual cost difference is not known. Nursing and provider staff time was prospectively recorded for all patients enrolled in the OB Nest clinical trial. Published 2015 national wages for healthcare workers were used to calculate the actual labor cost of providing either traditional or OB Nest prenatal care in 2015 US dollars. Overhead expenses and opportunity costs were not considered. Total provider cost was decreased caring for the OB Nest participants, but nursing cost was increased. OB Nest care required an average of 160.8 (+/− 45.0) minutes provider time and 237 (+/− 25.1) minutes nursing time, compared to 215.0 (+/− 71.6) and 99.6 (+/− 29.7) minutes for traditional prenatal care (P < 0.01). This translated into decreased provider cost and increased nursing cost (P < 0.01). Supply costs increased, travel costs declined, and overhead costs declined in the OB Nest model. In this trial, labor cost for OB Nest prenatal care was 34% higher than for traditional prenatal care. The increased cost is largely attributable to additional nursing connected care time, and in some practice settings may be offset by decreased overhead costs and increased provider billing opportunities. Future efforts will be focused on development of digital solutions for some routine nursing tasks to decrease the overall cost of the model. ClinicalTrials.gov Identifier: NCT02082275 .
Heartbeat: diagnosis and management of pericardial disease

[ ]in this issue of Heart is a short summary of the key changes in the European Society of Cardiology 2020 Guidelines for management of acute coronary syndromes without ST-elevation 5 A few of the major points are use of 0 and 1 hours rapid rule-out protocols, a preference for prasugrel over ticagrelor in patients undergoing invasive intervention, delayed angiography after resuscitated out-of-hospital cardiac arrest in haemodynamically stable patients and consideration of complete revascularisation in patients with multivessel disease who are not in cardiogenic shock The unfolding story of the interaction between the COVID-19 pandemic and cardiovascular mortality is addressed in a systematic review and meta-analysis showing that despite reduced rates of admission for ST-elevation myocardial infarction (STEMI) during the COVID-19 pandemic, hospital mortality was unchanged 6 Danchin and Marijon7 express the concern that although this apparent decrease in STEMI might be due to an actual decrease in event rates, it also is possible that ‘if the decrease was primarily due to fear of getting admitted in patients actually having had an AMI, we should observe an unusually increased rate in late complications potentially related to larger myocardial infarctions caused by the lack of appropriate management at the acute stage (eg, congestive heart failure or ventricular arrhythmias) ’ The article then focuses on multimodality imaging for ischaemic heart disease;discussing the strengths and limitation of exercise treadmill testing, coronary CT angiography, exercise or pharmacological single-photon emission (SPECT), or positron emission tomographic (PET) myocardial perfusion imaging, stress cardiovascular magnetic resonance or stress echocardiography
Breastfeeding During a Pandemic: The Influence of COVID-19 on Lactation Services in the Northeastern United States.

BackgroundPandemic-related restrictions have limited traditional models of lactation support.Research AimsThe primary aim of this study was to determine changes to breastfeeding support services du...
Targeted self-regulation interventions in low-income children: Clinical trial results and implications for health behavior change.

Abstract Self-regulation, known as the ability to harness cognitive, emotional, and motivational resources to achieve goals, is hypothesized to contribute to health behaviors across the lifespan. Enhancing self-regulation early in life may increase positive health outcomes. During pre-adolescence, children assume increased autonomy in health behaviors (e.g., eating; physical activity), many of which involve self-regulation. This article presents results from a clinical trial (NCT03060863) that used a factorial design to test behavioral interventions designed to enhance self-regulation, specifically targeting executive functioning, emotion regulation, future-oriented thinking, and approach biases. Participants were 118 children (9–12 years of age, M = 10.2 years) who had a history of living in poverty. They were randomized to receive up to four interventions that were delivered via home visits. Self-regulation was assayed using behavioral tasks, observations, interviews, and parent- and child-report surveys. Results were that self-regulation targets were reliably assessed and that interventions were delivered with high fidelity. Intervention effect sizes were very small to moderate (d range = .02–.65, median = .14), and most were not statistically significant. Intercorrelation analyses indicated that associations between measures within each target varied based on the self-regulation target evaluated. Results are discussed with regard to the role of self-regulation-focused interventions in child health promotion. Implications of findings are reviewed for informing next steps in behavioral self-regulation interventions among children from low-income backgrounds.
Intrinsic and extrinsic regulation of IgE B cell responses

Stringent regulation of IgE antibody production is critical for constraining allergic responses. This review discusses recent advances in understanding cell-intrinsic and extrinsic mechanisms that regulate the genesis and fate of IgE B cells. B cell-intrinsic regulation of IgE is orchestrated by the IgE B Cell Receptor (BCR). Through its antigen-independent signaling and low surface expression, the IgE BCR drives IgE B cells to differentiate into short-lived plasma cells and/or undergo apoptosis, restricting IgE-expressing cells from entering long-lived compartments. The pivotal extrinsic regulators of IgE responses are T follicular helper cells (TFH). TFH produce IL-4 and IL-21, which, respectively, are the major activating and inhibitory cytokines for IgE class-switching. Other newly identified T follicular subsets also contribute to IgE regulation. Although IgE responses are normally constrained, recent studies suggest that specific conditions can induce the formation of IgE responses with enhanced affinity or longevity, effectively 'breaking the rules' of IgE regulation.
Regulatory challenges of convalescent plasma collection during the evolving stages of COVID-19 pandemic in the US.

Regulations concerning COVID-19 convalescent plasma (CCP) collection during different stages of the pandemic have been challenging for the blood establishments. With the availability of advancing evidence about the safety and efficacy of CCP and the development of COVID-19 vaccines, the FDA regulations have been promptly updated at different stages of the pandemic. Evidence regarding the efficacy of high titer CCP and the antibody titer threshold required to qualify a unit as 'high titer', is still evolving. Evidence about the efficacy during early in the course of disease and in immunocompromised patients also requires larger prospective randomized controlled trials, and the major drawback of many existing clinical trials is their lack of randomization. We review the FDA regulatory updates for CCP collection during the pandemic and the challenges faced by blood donation centers, summarize the evidence for CCP efficacy, including efficacy against the SARS-CoV-2 variants and describe the future challenges and directions. This article is protected by copyright. All rights reserved.
Endplate deflection is a defining feature of vertebral fracture and is associated with properties of the underlying trabecular bone.

Endplate deflection frequently occurs with vertebral failure, but the relationship between the two remains poorly defined. This study examined associations between endplate deflection under compressive loading and characteristics of the neighboring subchondral bone and intervertebral disc (IVD). Ten L1 vertebrae with adjacent IVDs were dissected, compressed axially in a stepwise manner to failure, and imaged with micro-computed tomography before each loading step. From the images, deflection was measured across the surface of each endplate at each step. Trabecular microstructure and endplate volume fraction were evaluated in 5mm regions just under the superior endplate. IVDs were assessed using computed tomography and histology. A marked increase in superior endplate deflection coincided with a drop in the load-displacement curve. Endplate deflection was higher in regions with less robust bone microstructure (p<0.009), though these associations tended to weaken as loading progressed. Immediately following the ultimate point, endplate deflection was higher in regions underlying the nucleus pulposus vs. annulus fibrosus (p=0.035), irrespective of disc grade (p=0.346). These results indicate that a sudden increase in endplate deflection signals that the mechanical competence of the vertebra has been compromised. The mechanisms of endplate failure likely relate to anatomical features of the endplate, neighboring trabecular bone, and IVD.
The midforceps operation; preliminary study of 351 cases.

Abstract A preliminary report of the midforceps operations performed at the Hartford Hospital has been presented. The survey has been based upon the experience with 351 cases which occurred in approximately eighteen months; 72.6 per cent of the procedures were for arrest in rotation, and an additional 10.5 per cent for prolonged labor. There was no universal method of delivery. Apparently each obstetrician had his personal preference when confronted with a specific set of circumstances. The Scanzoni procedure was utilized approximately three times as often as the Kielland forceps. Despite the skill of various operators, maternal complications arose in 25.6 per cent of the cases, with sulcus tears, other vaginal lacerations, and lacerations of the cervix predominating. Follow-up of 73.1 per cent of the cases revealed cervical lacerations in 24.1 per cent and a combined total of 34.2 per cent cystocele, rectocele, and prolapse. Most amazing was a corrected stillbirth rate of zero and a neonatal mortality of only 0.29 per cent. D'Esopo 3 stated that an estimated cesarean section rate of 6.0 per cent would virtually eliminate all difficult midforceps procedures. At this hospital, however, the cesarean section rate was 8.2 per cent in 1952 and 9.4 per cent in 1953. During eighteen of these twenty-four months, we still delivered 351 babies by midforceps, with a 25.6 per cent incidence of maternal complications. Perhaps the more frequent use of x-ray pelvimetry might have decreased this figure by increasing the number of cesareans. It is our opinion that the number of cases included in this preliminary report is still too small to be of statistical significance. It is anticipated that the contemplated survey of ten years' experience with the operation will result in the formulation of definite conclusions regarding the procedure.
A Synthesis Algorithm for Hybrid Systems

Hybrid systems are systems of continuous plants, subject to disturbances, interacting with sequential automata in a network. By the synthesis problem for hybrid systems we mean extracting a finite state digital controller automaton from the system equations, constraints, and cost function which define the hybrid system. This automaton senses system state, and on the basis of its state, changes state and issues a chattering control to the actuators to control the system with epsilon optimal control for a fixed epsilon in real time. We address this problem by extracting a local cost function for the control system which transforms the infinite-dimensional optimization problem into a finite-dimensional problem.
IL-18, a product of choriodecidual cells, increases during premature rupture of membranes but fails to turn on the Fas - FasL-mediated apoptosis pathway

Problem: IL-18 is a novel cytokine, which promotes inflammation and apoptosis. This study examines its expression pattern, site of production, and levels in the amniotic fluid (AF) during pregnancy complications such as preterm labor and preterm premature rupture of membranes (pPROM). The ability of IL-18 to induce the Fas–Fas ligand (FasL)/caspase-mediated apoptotic pathway is also studied.
Reach-averaged sediment routing model of a canyon river

[1] Spatial complexity in channel geometry indicates that accurate prediction of sediment transport requires modeling in at least two dimensions. However, a one-dimensional model may be the only practical or possible alternative, especially for longer river reaches of practical concern in river management or landscape modeling. We have developed a one-dimensional model of the Colorado River through upper Grand Canyon that addresses this problem by reach averaging the channel properties and predicting changes in sand storage using separate source and sink functions coupled to the sand routing model. The model incorporates results from the application of a two-dimensional model of flow, sand transport, and bed evolution, and a new algorithm for setting the near-bed sand boundary condition for sand transported over an exposed bouldery bed. Model predictions were compared to measurements of sand discharge during intermittent tributary inputs and varying discharges controlled by dam releases. The model predictions generally agree well with the timing and magnitude of measured sand discharges but tend to overpredict sand discharge during the early stages of a high release designed to redistribute sand to higher-elevation deposits.
Orientational Phases of Hydrogen Molecules on a Triangular Lattice

A mean-field theory for the ordering of hydrogen molecules on a triangular net is derived in terms of the quadrupole coupling constant Γ, the crystal field Vc, and the temperature T. The phase diagram consists of six regions, separated by firstand second-order transitions. For almost all values of Vc/Γ for which ordering occurs, the disordered to ordered phase transition is continuous. At T=0 K, all phases have energy gaps except for a ferrorotational phase which behaves like an XY model.
Limited Partnerships Revisited

This article surveys changes in limited partnerships and limited partnership law and analyzes the current effort by the National Conference of Commissioners on Uniform State Laws (NCCUSL) to revise the Uniform Limited Partnership Act. The article criticizes the project in light of theories and evidence on uniform laws and statutory standard forms and NCCUSL's institutional shortcomings as a promoter of uniformity.
Development of a 1.5 micron acetylene stabilised frequency standard and the measurement of its frequency using single Sr/sup +/ standard

We report progress on the development of an optical frequency standard at 1.5 micron referenced to rovibrational transitions in acetylene. This work not only yields a frequency reference of relevance to precision physical measurements, but also addresses the near term need for 100 kHz-1 MHz accuracy in calibration procedures for dense WDM optical communication systems. Absolute frequency measurements of a tuneable diode laser stabilized on the acetylene saturated-absorption lines are being carried out using a link to the accurate NRC single ion reference.
Power Supplies for Cold Cathode Penning Discharge Ion Sources

For the generation of heavy ions at high charge states, the cold-cathode Penning discharge ion source requires a power supply capable of both the high potential essential for striking an arc and the high current for sustaining it. A series-regulated power supply developed at Oak Ridge provides up to 6 kV of striking voltage and up to 12 amperes of arc current. The power supply operates in a constant current mode with the arc voltage dependent on the gas pressure in the ion source. With this source in ORIC, the typical operating conditions are 5 to 10 amperes arc current, 600 to 2000 volts arc potential, and 5 to 20 kW power dissipation in the arc. A larger power supply is planned for extending the arc current to about 25 amperes. Various arrangements, including pre-regulators and multiple power supplies, are under consideration to reduce power dissipation in the series regulator tubes.
The behavior of model Ag/Al2O3 catalysts in various chemical environments

Abstract The sintering behavior of silver crystallites supported on nonporous alumina substrates has been investigated by means of transmission electron microscopy. When the specimens were heated in O 2 at temperatures in the range 250–400 °C, the following phenomena were observed: crystallite migration and coalescence, disappearance of small and large particles, decrease in size of small crystallites, and appearance of a large number of small crystallites of circular or wormlike shape. A few possible explanations are suggested for the appearance of a large number of small particles. The behavior of silver particles heated in H 2 at temperatures in the range 300–400 °C was qualitatively similar to that observed in O 2 . Sintering was, however, less severe, and the number of small particles that appeared was smaller. When heated in C 2 H 4 , the particles changed their shape from circular to ellipsoidal and, with few exceptions, remained almost unchanged in their locations, most probably as a result of carbon deposition on the surface and around the particles. When heated in a mixture of C 2 H 4 and O 2 , the particles exhibited milder sintering than in O 2 , but acquired more irregular shapes, as during their heating in C 2 H 4 .
Implementation of an electronic medical record does not change delivery of preventive care for HIV-positive patients

Abstract Purpose This study sought to determine the impact that an electronic medical record (EMR) had on the provision of preventive health measures – including obtaining serologies for viral hepatitis and administering vaccinations to non-immune patients – to HIV patients at a hospital-based clinic. Methods Using a pre–post study design, we compared rates of preventive health delivery to HIV patients at an outpatient clinic during the use of a paper medical record (PMR) and after implementation of an EMR. Retrospective chart reviews were conducted at two time points: 12–16 months prior to and 24 months following EMR implementation. The records of 160 active patients were randomly selected for review during both time periods. Results There was no difference between the PMR and EMR samples with regard to the proportion of patients who had hepatitis A (83% in PMR group; 77% in EMR) and hepatitis C (94% in both groups) serologies measured or the proportion of eligible patients who were given hepatitis vaccinations. Slightly fewer patients had a serology for hepatitis B measured in the EMR sample. Conclusions As EMR implementation expands, it is important to evaluate the effects that EMRs have on patient outcomes, including preventive health provision. Our study showed that after implementation of an EMR, the provision of most preventive care measures did not improve. This finding is in agreement with many published studies. Some studies have found positive effects from EMRs that may be attributable to specific aspects of EMRs. Further study of the effect of specific EMR attributes on health care outcomes is needed.
Monotone methods for a finite difference system of reaction diffusion equation with time delay

Abstract The aim of this paper is to present some monotone iterative schemes for computing the solution of a system of nonlinear difference equations which arise from a class of nonlinear reaction-diffusion equations with time delays. The iterative schemes lead to computational algorithms as well as existence, uniqueness, and upper and lower bounds of the solution. An application to a diffusive logistic equation with time delay is given.
Electrochemically stimulated release of lysozyme from an alginate matrix cross-linked with iron cations

An electrochemically generated alginate matrix cross-linked with Fe3+ cations was used to entrap lysozyme and then release it upon application of an electrochemical signal. The switchable behavior of the alginate hydrogel was based on the different interaction of Fe3+ and Fe2+ cations with alginate. The oxidized Fe3+ cations strongly interact with alginate resulting in its cross-linking and formation of the hydrogel, while the reduced Fe2+ cations weakly interact with alginate and do not keep it in the hydrogel state. Thus, the electrochemical oxidation of iron cations at +0.8 V (Ag/AgCl) in the presence of alginate and lysozyme resulted in the Fe3+-cross-linked alginate hydrogel thin-film on the electrode surface with the physically entrapped lysozyme. On the other hand, application of reductive potentials (e.g. −1.0 V) converted the iron cations to the Fe2+ state, thus resulting in dissolution of the alginate thin-film and lysozyme release. The bactericidal effect of the electrochemically released lysozyme was tested on the Gram-positive bacterium Micrococcus luteus demonstrating the same activity as the unadulterated lysozyme commercially supplied by Sigma-Aldrich. The present result represents the first step towards drug delivering systems (exemplified by the lysozyme release) based on alginate hydrogels and activated by electrochemical stimuli.
Knowledge and skill retention of emergency care attendants, EMT-As, and EMT-Ps.

The retention of knowledge and skill proficiency was evaluated for emergency care attendants (ECAs), emergency medical technicians (EMT-As) and paramedics (EMT-Ps). The sample represented 4.1% of the total number of individuals trained and certified in these positions in Texas. The average loss of didactic knowledge did not exceed 10% over a two-year period. After two years the ECAs had lost approximately 55%, EMT-As 50%, and EMT-Ps 61% of their basic skills proficiency. Retention of knowledge and skill appears to be directly related to frequency of use. Participants in continuing education programs experienced an 11% better retention average for skill than did nonparticipants. The employees of privately operated ambulance services retained their basic skills better than did members of other types of services. The rate of knowledge deterioration for the sample evaluated was not correlated ( R = 0.08) to the original written score.
Enrichment of Hepatocyte-like Cells with Upregulated Metabolic and Differentiated Function Derived from Embryonic Stem Cells Using S-NitrosoAcetylPenicillamine

The generation of a large number of fully functional hepatocytes from a renewable cell source can provide an unlimited resource for bioartificial liver devices and cell replacement therapies. We ha...
Formation of stable p53 homotetramers and multiples of tetramers.

We have used gradient gel electrophoresis and chemical cross-linking to analyze the quaternary structure of purified, wild-type, murine p53. Under nondenaturing conditions, p53 electrophoreses as tetramers and multiples of tetramers. Under denaturing conditions, fully cross-linked p53 also behaves as tetrameric structures. We confirmed the composition of the tetramers by partially cross-linking p53 and dissociating tetramers into monomers, dimers, and trimers. © 1992 wiley-Liss, Inc.
Adjunctive behavior in multiple schedules of reinforcement

A recent theory of timing (Killeen & Fetterman, 1988) suggests that adjunctive behaviors may act as discriminative cues for the passage of time and that the rate of transition between those behaviors is affected by the rate of reinforcement within the experimental context. Is the rate of transition between behaviors correlated with the rate of reinforcement? What is the context in which rate of reinforcement is calibrated? If rate of transition is correlated with reinforcement frequency, does this correlation change with extended training? Four pigeons were trained on multiple fixed-time schedules of reinforcement, with one component always FT 15 sec, the other either FT 15 sec, FT 45 sec, or FT 5 sec. Behavior was coded into one of 12 categories. Response distributions in the constant component shifted when rate of reinforcement was varied in the other component and eventually shifted back toward their original location.
New simplified technique for 3D mapping and ablation of right ventricular outflow tract tachycardia.

Objective: To evaluate the safety and efficacy of using a circular multielectrode catheter for mapping and ablation of ventricular tachycardia (VT) or premature ventricular complexes (PVCs) from the right ventricular outflow tract (RVOT). Background: Three-dimensional (3D) mapping systems are commonly used for mapping and ablation of RVOT VT and PVCs. Newer catheters that are circular with multiple electrodes, such as the Lasso catheter, are capable of simultaneously recording from multiple points within a circumferential plane. Given the tubular structure of the RVOT, these catheters could be used for mapping tachycardias from the RVOT. Methods: A retrospective cohort study of patients undergoing radiofrequency (RF) ablation of RVOT VT or PVCs was performed. In group 1 (n = 7), mapping was performed with a single ablation catheter and fluoroscopy. In group 2 (n = 10), 3D mapping using ESI (n = 9) or CARTO (n = 1) was performed. In group 3 (n = 12), mapping was performed with a circular multielectrode catheter (n = 12). All ablations were performed with 4-mm tip catheters using RF energy. Results: Catheter ablation for RVOT VT (n = 15) or PVCs (n = 14) was performed on 29 cases in 26 patients, 9 males. Mean age was 35.9 years. In groups 1, 2, and 3, the mean number of lesions was 17.7 ± 7.7, 13.6 ± 7.7, and 18.2 ± 22.7 and the median number of lesions was 20, 13, and 5, respectively. There were no significant differences in the number of lesions, RF time, fluoroscopy time, procedure time, and acute success rate among the three techniques. There were three complications in group 2 and one in group 3. Conclusion: The use of a circular multielectrode catheter is as effective as the other standard available 3D mapping techniques, both in terms of procedural success and procedural characteristics. Additionally, because of the lower cost associated with using the circular multielectrode catheter approach, further evaluation should be performed to determine whether this is the most cost-effective approach to 3D mapping and ablation of RVOT tachycardias.
Theory of spin coherence in semiconductor heterostructures

Abstract Consideration of the spin degrees of freedom of the carriers in semiconductor heterostructures creates interesting possibilities for spin optoelectronics, magnetoelectronics and quantum computing. This theory paper attempts to explain in simple terms the concepts of optical and spin coherence, how they can be observed, simple deductions of the spin dynamics in magnetic fields, exciton interaction effects, exciton exchange effects and the spin transport across semiconductor–metal interface.
Deriving aerosol properties from satellite: in situ and satellite comparisons

The ability to derive aerosol properties from satellites is important for climate change studies and atmospheric corrections in studying surface properties. Although aerosols have been measured over land from satellite, it is more feasible to measure them over low surface albedos such as the ocean. One of the uncertainties that must be dealt with is the aerosol phase function, which depends on the aerosol size distribution and the observing wavelength.
Visibility and intersectin problems in plane geometry

We develop new data structures for solving various visibility and intersection problems about a simple polygon P on n vertices. Among our results are a simple O(n log n) algorithm for computing the illuminated subpolygon of P from a luminous side, and an O(log n) algorithm for determining which side of P is first hit by a bullet fired from a point in a certain direction. The latter method requires preprocessing on P which takes time O(n log n) and space O(n). Our main new tool in attacking these problems is geometric duality on the two-sided plane.
Bone Mineral Density, Androgens, and the Polycystic Ovary: The Complex and Controversial Issue of Androgenic Influence in Female Bone

Polycystic ovary syndrome (PCOS), characterized by chronic anovulation, hyperandrogenemia, obesity, central adiposity, and insulin resistance (1–3), represents a unique, natural model for study of the influences of androgenic hormones on bone mass among women. PCOS usually manifests at puberty and is currently recognized as one of the most common endocrine disorders among women of reproductive age, affecting approximately 4% of this population (4). Women with PCOS typically have acyclic production of 17b-estradiol, with circulating concentrations similar to those seen in the follicular phase of cycling women, but considerably lower than the mean 17b-estradiol concentration observed across the normal menstrual cycle (1). This static level of 17b-estradiol, with the absence of the estradiol surge associated with ovulation, would intuitively be expected to negatively affect bone density. Testosterone and androstenedione, however, are produced in excess by the PCOS ovary and perhaps by the adrenals of some affected women. This chronic elevation in androgens may exert a positive influence on bone in PCOS women, either directly through androgen receptors on bone-related cells or indirectly after conversion to 17b-estradiol and estrone, respectively, in peripheral tissues. Moreover, elevated circulating insulin levels, also associated with PCOS, may offer some additional protection against a reduction in bone mass in these women. Hyperinsulinemia has been shown to positively affect bone density (5, 6) through direct stimulatory effects on osteoblastic activity (7) and by the suppressive influences exerted by insulin on the production of sex hormone-binding globulin (SHBG) (8) and insulin-like growth factor (IGF)-binding proteins (IGFBPs) (9). This insulininduced suppression of these binding proteins may result in increased exposure of target tissues, including bone, to the stimulatory effects of elevated concentrations of free sex steroids and IGFs. Both thin and obese women develop PCOS, a presentation that allows for evaluation of the effects of life-long obesity, alterations in body composition (e.g. increased central adiposity), and related metabolic abnormalities (e.g. hyperandrogenemia and hyperinsulinemia) on the skeleton. The relatively high prevalence of PCOS and its early-life presentation render this disorder of particular importance as a model for assessing the effects of androgen and potentially insulin on the attainment of maximal bone mass. The objectives of this review article are to 1) summarize the literature exploring the androgen-bone mass relationship in normal women; 2) assess the effects of PCOS, androgen excess, and androgen-estrogen balance on bone mass in women; 3) examine study design issues related to PCOS, androgen excess, and bone mass; and 4) suggest areas for future research related to the influence of PCOS, androgen excess, and insulin on bone in women.
Using Innovative Learning Technologies to Promote Learning and Engagement in an Urban Science Classroom

Recent reform movements within the United States have called for science for all and educational reforms to support this goal. In light of these reform movements and concerns regarding learning wit...
The ion electric microfield gradient joint probability distribution function for dense plasmas

Abstract The plasma quasistatic ion electric microfield can be used to describe the effect of the many perturbing ions in a plasma on a single charged particle such as an atomic ion. Microfield spatial derivatives at the charged particle describe the non-uniformity of the electric microfield on the atomic scale and are important for higher-order multipole interactions between the plasma and atomic ions. An example of these multipole effects is the ion-quadrupole effect that leads to the asymmetric broadening of spectral lines. We examine approximations to the constrained electric microfield gradient joint probability distribution function which describes the probability of particular field gradients given a particular value of the plasma microfield. We employ molecular dynamics simulations and analytic approximations based on the APEX microfield description. We find that corrections to a previously published approximation to this joint probability function can be important and that under certain conditions, these probability functions may be approximated by Gaussian distributions. We present a theory for estimating the widths of these Gaussian approximations.
The effect of Pt on Ni3Al surface oxidation at low-pressures

Abstract The fully-oxidized surface that forms on (1 1 1) oriented Ni 3 Al single crystals, with and without Pt addition, at 300–900 K under oxygen pressures of ca. 10 −7 Torr was studied using XPS, AES, and LEIS. Two main types of surfaces form, depending upon oxidation temperature. At low-temperature, the predominant oxide is NiO, capped by a thin layer of aluminum oxide, which we refer to generically as Al x O y . At high-temperature (i.e., 700–800 K), NiO is replaced by a thick layer of Al x O y . By comparing samples that contain 0, 10 and 20 at.% Pt in the bulk, we find that the effect of Pt is to: (1) reduce the maximum amount of both NiO and Al x O y ; and (2) shift the establishment of the thick Al x O y layer to lower temperatures. Platinum also decreases the adsorption probability of oxygen on the clean surface.