cssi/SciSciGPT-SciSciNet huggingface dataset:
A crack-mechanics based model for damage and plasticity of brittle materials under dynamic loading

A rate-dependent model for damage and plastic deformation of brittle materials under dynamic loading is presented. The model improves upon a recently developed micromechanical damage model (Zuo et al., 2006) by incorporating plastic deformation of the material. The distribution of the microcracks in the material is assumed to remain isotropic, and the damage evolution is through the growth of the average crack size. Plasticity is considered through an additive decomposition of the total strain rate, and a rate-independent, von Mises model is used. The model was applied to simulate the response of a model material (SiC) under uniaxial strain loading. To further examine the behavior of the model, cyclic loading and large-strain compressive loading were considered. Numerical results of the model predictions are presented, and comparisons with those from a previous model are provided.
Two-photon wave mechanics

The position-representation wave function for multiphoton states and its equation of motion are introduced. A major strength of the theory is that it describes the complete evolution (including polarization and entanglement) of multiphoton states propagating through inhomogeneous media. As a demonstration of the two-photon wave function's use, we show how two photons in an orbital-angular-momentum entangled state decohere upon propagation through a turbulent atmosphere.
Quality of college students' experiences during cooperative learning

This study examined the quality of college students' experiences during cooperative learning (CL) tasks. Undergraduate educational psychology students were assigned to small groups to discuss how they could apply important psychological principles to teaching—learning projects. In addition to responding to questionnaires measuring goal orientations, attitudes toward CL, and perceived ability in educational psychology, they were interrupted during a small-group discussion using Csikszentmihalyi, Rathunde, and Whalen's (1993) experience sampling method to measure their quality of experience. Results indicated that quality of experience was predicted by perceived skill for the task, as well as importance of the task. Measures of pre-existing individual differences were not predictive.
Interference minimizing channel assignment using partially overlapped channels in multi-radio multi-channel wireless mesh networks (non-refereed)

Channel assignment algorithms revealed so far in the literature for multi-radio multi-channel wireless mesh networks (MRMC-WMN) mainly deals with orthogonal channels (non-overlapped channels). But considering the total number of available orthogonal channels in the case of IEEE 802.11b, which is limited to only 3 channels. Therefore, this lack of availability of assignable channels causes inefficient use of spectrum resources. It is very difficult to design a feasible channel assignment algorithm using only orthogonal channels that is interference-aware and throughput maximizing, whereas it also minimizes switching delay and at the same time makes the best utilization of spectrum resources. We had taken the novel approach of satisfying the above goals through the smartly utilization of partially overlapped channels (POC). We also introduce the notion of a 3D Node-Radio-Channel (NRC) graph model for characterizing the topological structure along with interfaces associated with different channels at each node.
Computer generation of gamma random variates with non-integral shape parameters

When the shape parameter, a, is integral, generating gamma random variables with a digital computer is straightforward. There is no simple method for generating gamma random variates with non-integral shape parameters. A common procedure is to approximately generate such random variables by use of the so-called probability switch method. Another procedure, which is exact, is due to Johnk. This paper presents a rejection method for exactly generating gamma random variables when a is greater than 1. The efficiency of the rejection method is shown to be better than the efficiency of Johnk's method. The paper concludes that when a is non-integral the following mix of procedures yields the best combination of accuracy and efficiency: (1) when a is less than 1, use Johnk's method; (2) when 1 is less than a and a is less than 5, use the rejection method; (3) when a is greater than 5, use the probability switch method.
Evolution of fluid pressure and fracture propagation during contact metamorphism

Rock fracture enhances permeability and provides pathways through which fluids migrate. During contact metamorphism, fluids contained in isolated pores and fractures expand in response to temperature increases caused by the dissipation of heat from magmas. Heat transport calculations and thermomechanical properties of water-rich fluids demonstrate (1) that thermal energy is a viable mechanism to produce and maintain pore fluid pressure (Pf) in a contact metamorphic aureole; (2) that the magnitude of Pf generated is sufficient to propagate fractures during the prograde thermal history (cause hydrofracture) and enhance permeability; and (3) that Pf-driven fracture propagation is episodic with time-scales ranging from years to thousands of years. Because Pf dissipation is orders of magnitude faster than P, f buildup, Pf oscillations and cyclical behaviour are generated as thermal heating continues. The Pf cycle amplitude depends on the initial fracture length, geometry and the rock's resistance to failure whereas the frequency of fracture depends on the rate of heating. Consequently, oscillation frequency also varies spatially with distance from the heat source. Time series of fluid pressures caused by this process suggest that cyclical fracture events are restricted to an early time period of the prograde thermal event near the intrusive contact. In the far field, however, individual fracture events have a lower frequency but continue to occur over a longer time interval. Numerous fracture cycles are possible within a single thermal event. This provides a provisional explanation for multiple generations of veins observed in outcrop. Pf cycling and oscillations may explain several petrological features. If pore fluids are trapped at various positions along a pressure cycle, the large amplitude of Pf variations for small fractures may account for different pressures recorded by fluid inclusions analysed from a single sample. Pf oscillations, during a single thermal episode, also drive chemical reactions which can produce complex mineral textures and assemblages for discontinuous reactions and/or zoning patterns for continuous reactions. These can mimic polymetamorphic or disequilibrium features. Temporal aspects of fracture propagation and permeability enhancement also constrain the likely timing of fluid flow and fluid-mineral interactions. These data suggest that fluid flow and fluid-mineral reactions are likely to be restricted to an early period in the prograde thermal history, characterized by high Pf coincident with relatively high temperatures, fracture propagation and consequent increases in permeability. This early prograde hydration event is followed by diffusional peak metamorphic reactions. This relationship is evident in the complex mineralogical textures common in some metamorphosed rocks.
A biotelemetry study of the thermoregulatory patterns of Tamias striatus and Eutamias minimus during hibernation

Abstract The hibernation period of Tamias striatus is composed of a test drop, pre-plateau and plateau stage. The number of test drops during the test drop stage increases with a lowering of ambient temperature. The number of torpor bouts during the pre-plateau stage increases with a lowering of ambient temperature. The duration of bouts of torpor during the plateau stage increases linearly with a decrease in ambient temperature. (duration in hr = 139·60−5·93 Ta). Tamias striatus displays a control on the rate of cooling during the entry into a torpor bout. Differential rates of cooling are observed between torpor bouts occurring during the test drop and post-test drop stages at the ambient temperatures of 8°, 6° and 3°C but not at 16°, 13° and 10°C. The hibernation period of Eutamias minimus is composed of a pre-plateau and plateau stage. Eutamias minimus displays significantly longer durations of torpor during the plateau stage than Tamias striatus. Eutamias minimus displays a control on the rate of cooling during the entry into a torpor bout. Eutamias minimus is a “deeper” hibernator than Tamias striatus, i.e. less prone to arousals.
Control of the magnetism and magnetic anisotropy of a single-molecule magnet with an electric field.

Through systematic density functional calculations, the mechanism of the substrate induced spin reorientation transition in FePc/O-Cu(110) is explained in terms of charge transfer and rearrangement of Fe-3d orbitals. Moreover, we find giant magnetoelectric effects in this system, manifested by the sensitive dependence of its magnetic moment and magnetic anisotropy energy on an external electric field. In particular, the direction of magnetization of FePc/O-Cu(110) is switchable between in-plane and perpendicular axes, simply by applying an external electric field of 0.5 eV/A along the surface normal.
Stimulation by polyamines of carbamylphosphate:glucose phosphotransferase and glucose-6-phosphate phosphohydrolase activities of multifunctional glucose-6-phosphatase.

Abstract The effects of added polyamines on carbamylphosphate (carbamyl-P): glucose phosphotransferase and glucose-6-phosphate (Glc-6-P) phosphohydrolase activities of rat hepatic D -Glc -6-P phosphohydrolase (EC 3.1.3.9) of intact and detergent-treated microsomes have been investigated. With the former preparation, in the presence of 1.4 mM phosphate substrate and 90 mM D -glucose (phosphotransferase), 1 mM spermine, spermidine, and putrescine activated Glc-6-P phosphohydrolase 67%, 57%, and 35%, respectively. Carbamyl-P:glucose phosphotransferase, under comparable conditions, was activated 57%, 34%, and 18%. NH4+ (0.25–5.0 mM) produced at best but a minor activation (0–14%), while poly( L -lysine) (Mr = 3400; degree of polymerization 16) equimolar relative to other polyamines with respect to ionized free amino groups activated the hydrolase 358% and the transferase 222%. Treatment of microsomes with the detergent deoxycholate reduced, but did not abolish, polyamine-induced activation. The stimulatory effects of polyamines persisted in the presence of excess catalase, indicating their independence from H2O2 formation; and were eliminated in the presence of Ca2+. Kinetic analysis revealed that all tested polyamines decreased the apparent Michaelis constant values for carbamyl-P and Glc-6-P, but had no effect on the Km for glucose. Poly( L -lysine) increased the V value for both Glc-6-P phosphohydrolase and apparent V values for phosphotransferase extrapolated to infinite concentrations of either carbamyl-P or glucose. The other tested polyamines elevated only this last velocity parameter. It is proposed that a major mechanism by which polyamines activate glucose-6-phosphatase-phosphotransferase is through their electrostatic interactions with phospholipids of the membrane of the endoplasmic reticulum of which this enzyme is a part. Conformational alterations thus induced may in turn affect catalytic behavior. It is suggested that polyamines, or similar positively charged peptides, might participate in the cellular regulation of synthetic and hydrolytic activities of glucose-6-phosphatase.
Validity of the Rytov Approximation

The limitations on the applicability of the Rytov approximation are examined in this paper. It is shown that (1) the singular behavior of the perturbation series of which the Rytov approximation is the first term cannot be removed by adding a “constant” as suggested by the proponents of Rytov’s method; (2) the validity of Rytov approximation is limited to situations in which the mean-square value of the logarithmic amplitude fluctuation is much smaller than unity; (3) the MTF data of Coulman do not provide a good test on the validity of the Rytov approximation; (4) experimental data on the range dependence of intensity fluctuations do not agree with the predictions of the Rytov approximation; and (5) in problems involving propagation near the zenith, the validity of the Rytov approximation is limited to the near field of the turbulent layers at the surface of the earth and near the tropopause.
A five-phase model for clinical-outcome research.

Abstract Through a variety of approaches, speech-language pathologists and audiologists have produced strong evidence that treatments are generally potent. However, we have largely ignored the accepted standards for clinical-outcome testing used throughout the broader research community (e.g., by other clinical disciplines, federal regulators, and third-party payers). Several clinical professions recognize a comprehensive model for organizing and scaffolding the many forms of clinical-outcome research. An adaptation of this five-phase model of clinical-outcome research is examined as a means for structuring forms of clinical research throughout audiology and speech-language pathology. Within the organizing structure, relationships become apparent between types and grades of scientific evidence and the processes underpinning evidence-based practice which ultimately lead to decisions on the status of intervention protocols. Learning outcomes 1. Readers will be able to distinguish the phases of clinical-outcome research in a comprehensive model. 2. Readers will be able to identify relationships between the structure of the model and broadly recognized concepts associated with the terms ‘efficacy’ and ‘effectiveness.’ 3. Readers will be able to identify indicators of quality for controlled clinical trials.
A Qualitative Model of Human Interaction with Complex Dynamic Systems

A qualitative model describing human interaction with complex dynamic systems is developed. The model is hierarchical in nature and consists of three parts: a behavior generator, an internal model, and a sensory information processor. The behavior generator is responsible for action decomposition, turning higher level goals or missions into physical action at the human-machine interface. The internal model is an internal representation of the environment which the human is assumed to possess and is divided into four submodel categories. The sensory information processor is responsible for sensory composition. All three parts of the model act in consort to allow anticipatory behavior on the part of the human in goal-directed interaction with dynamic systems. Human workload and error are interpreted in this framework, and the familiar example of an automobile commute is used to illustrate the nature of the activity in the three model elements. Finally, with the qualitative model as a guide, verbal protocols from a manned simulation study of a helicopter instrument landing task are analyzed with particular emphasis on the effect of automation on human-machine performance.
Defective translational control facilitates vesicular stomatitis virus oncolysis

Abstract Vesicular stomatitis virus (VSV) exerts potent antitumor activity, although the molecular mechanisms underlying its oncolytic properties remain to be fully clarified. Here, we demonstrate that normally resistant murine embryonic fibroblasts are rendered highly permissive to VSV replication following cellular transformation, a progression that appears to compromise the antiviral effects of interferon (IFN). Subsequent studies revealed normal dsRNA-dependent protein kinase (PKR) activation and phosphorylation of eukaryotic initiation factor 2 (eIF2) α. Nevertheless, eIF2B-mediated guanine nucleotide exchange activity downstream of eIF2 was frequently aberrant in transformed cells, neutralizing eIF2α phosphorylation and permitting VSV mRNA translation. Thus, defects in translational regulation can cooperate with impaired IFN signaling to facilitate VSV replication, and may represent a common hallmark of tumorigenesis.
Mapping single and multiple multilevel structures onto the hypercube

The paper introduces algorithms that map single and multiple multilevel structures onto the hypercube. For the case of the pyramid, which is a special multilevel structure, it is shown that a new algorithm is a compromise among existing algorithms with regard to cost and performance. Comparative analysis of the algorithms is carried out using analytical techniques and simulation results.
Fat Reduces Volatiles Production in Oil Emulsion System Analyzed by Purge-and-Trap Dynamic Headspace/Gas Chromatography

Release of volatiles in oil emulsion systems containing various fat contents was determined using purge-and-trap dynamic headspace/gas chromatography. Oil emulsions were prepared using 0, 0.5, 1, 2, 4, or 8% oil, and a standard mixture was prepared using hydrocarbons, aldehydes, ketones, and alcohols. Fat content in oil emulsions reduced the volatility of added volatile standards, and the amount of volatiles released from oil emulsion correlated negatively with fat content (r 2 = 0.92 in total volatiles). Among these tested, the volatilization of ketones was least influenced by fat content. The release of nonpolar hydrocarbons was not influenced but polar compounds (aldehydes, ketones, and alcohols) were greatly influenced by water.
Some aspects of the gastrointestinal microflora of germfree mice associated with cultured microfloras.

Summary Attempts are described to 'normalize' germfree mice by association with 3, 21 and 71 different intestinal bacterial cultures isolated from mice with an SPF flora. Germfree mice associated .naturally with an SPF flora served as controls. Vital bacterial counts were determined by aerobic and anaerobic culture. Stomach and small intestine contained fewer bacteria per gram than caecum and large intestine. Aerobic vital counts from caecum and large intestine were higher in the experimental groups than in control mice. The aerobic and anaerobic flora in stomach and small intestine comprised mainly Gram-positive nonfusiform shaped rods. In the caecum and colon Gram-positive cocci predominated in the aerobic culture while in the anaerobic culture fusiformshaped rods were prominent. Scanning electron microscopy of oesophagus, ileum, caecum and faeces demonstrated colonization of the oesophageal epithelium only after association with 71 bacterial strains; the filamentous bacteria present in the ileum of SPF mice were not found in the experimental groups and caecum and faeces contained mainly fusiform-shaped bacteria. Nonbacterial matter decreased in the caecum and faeces with increase in the complexity of the flora. In laboratory animal science there exists a need to standardize laboratory animals. Microbiological standardization and manipulation of the microflora of laboratory animals are required for several research fields. In the present study we investigated some qualitative and quantitative aspects of the intestinal micro flora of germfree mice which were associated with combinations of bacterial strains cultured from the intestines of mice with a 'normal' microflora. After birth, bacterial colonization of mice occurs in a strict sequence (Schaedler, Dubos & Costello, 1965; Savage, Dubos & Schaedler, 1968). We tried to follow the natural sequence by associating germfree mice with microfloras cultured Received 25 August 1982. Accepted 15 December 1982. from SPF mice of 5, 20 and 60 days of age and investigating each stage. Vital bacterial counts and morphology of bacteria isolated from the stomach, small intestine, caecum and large intestine were studied. In addition the micro flora of the oesophagus, ileum, caecum and faeces was examined using a scanning electron microscope (SEM).
Impaired neonatal macrophage phagocytosis is not explained by overproduction of prostaglandin E2

Background Neonates and young infants manifest increased susceptibility to bacterial, viral and fungal lung infections. Previous work has identified a role for eicosanoids in mediating host defense functions of macrophages. This study examines the relationship between alveolar macrophage (AM) host defense and production of lipid mediators during the neonatal period compared to adult AMs.
Preparing to predict: The Second Autonomous Ocean Sampling Network (AOSN-II) experiment in the Monterey Bay

Abstract The Autonomous Ocean Sampling Network Phase Two (AOSN-II) experiment was conducted in and offshore from the Monterey Bay on the central California coast during July 23–September 6, 2003. The objective of the experiment was to learn how to apply new tools, technologies, and analysis techniques to adaptively sample the coastal ocean in a manner demonstrably superior to traditional methodologies, and to use the information gathered to improve predictive skill for quantities of interest to end-users. The scientific goal was to study the upwelling/relaxation cycle near an open coastal bay in an eastern boundary current region, particularly as it developed and spread from a coastal headland. The suite of observational tools used included a low-flying aircraft, a fleet of underwater gliders, including several under adaptive autonomous control, and propeller-driven AUVs in addition to moorings, ships, and other more traditional hardware. The data were delivered in real time and assimilated into the Harvard Ocean Prediction System (HOPS), the Navy Coastal Ocean Model (NCOM), and the Jet Propulsion Laboratory implementation of the Regional Ocean Modeling System (JPL/ROMS). Two upwelling events and one relaxation event were sampled during the experiment. The upwelling in both cases began when a pool of cold water less than 13 °C appeared near Cape Ano Nuevo and subsequently spread offshore and southward across the bay as the equatorward wind stress continued. The primary difference between the events was that the first event spread offshore and southward, while the second event spread only southward and not offshore. The difference is attributed to the position and strength of meanders and eddies of the California Current System offshore, which blocked or steered the cold upwelled water. The space and time scales of the mesoscale variability were much shorter than have been previously observed in deep-water eddies offshore. Additional process studies are needed to elucidate the dynamics of the flow.
Comparative Pulmonary Toxicological Assessment of Oil Combustion Particles Following Inhalation or Instillation Exposure

Controversy persists regarding the validity of intratracheal instillation (IT) of particulate matter (PM) as a surrogate for inhalation exposure (IH) in rodents. Concerns center on dose, doserate, and distribution of material within the lung. Acute toxicity of a residual oil fly ash (ROFA) administered by IH was compared to those effects of a single IT bolus at an IH-equivalent dose. Male Sprague Dawley rats (60 days old) were exposed by nose-only IH to ~12 mg/m 3 for 6 h. Inter-lobar dose distribution of ROFA, dissected immediately post exposure, was assayed by neutron activation. Vanadium and nickel were used as ROFA markers. IT administration of the IH-equivalent dose (110 mg) showed similar ( IH~25%). Evaluation of airway hyperreactivity (AHR), bronchoalveolar lavage fluid (BALF) constituents, and histopathology was conducted at 24, 48, and 96 h post exposure. AHR in the IH group was minimally (p > 0.05) affected by treatment, but was significantly increased (~40%) at both 24 and 48 h post IT. Inflammation in both groups, as measured by alterations in BALF protein, lactate dehydrogenase and neutrophils, was virtually identical at all time points. Alveolitis and bronchial inflammation/epithelial hypertrophy were prominent 24 h following IT, but not apparent after IH. Conversely, alveolar hemorrhage, congestion, and airway exudate were pronounced at 48 h post-IH but not remarkable in the IT group. Thus, IT-ROFA mimicked IH in terms of lobar distribution and injury biomarkers over 96 h, while morphological alterations and AHR appeared to be more dependent on the method of administration.
An Engagement Model of Cognitive Optimization Through Adulthood

The engagement hypothesis suggests that social and intellectual engagement may buffer age-related declines in intellectual functioning. At the same time, some have argued that social structures that afford opportunities for intellectual engagement throughout the life span have lagged behind the demographic shift toward an expanding older population. Against this backdrop, we developed the Senior Odyssey, an existing team-based program of creative problem solving. We tested the engagement hypothesis in a field experiment. Relative to controls, Senior Odyssey participants showed improved speed of processing, marginally improved divergent thinking, and higher levels of mindfulness and need for cognition after the program. This pilot translational project suggests that the Senior Odyssey program may serve as one effective model of engagement with good scaling-up potential.
Importance of Reward and Prefrontal Circuitry in Hunger and Satiety: Prader-Willi Syndrome vs. Simple Obesity

The majority of research on obesity (OB) has focused primarily on clinical features (eating behavior, adiposity measures) or peripheral appetite-regulatory peptides (leptin, ghrelin). However, recent functional neuroimaging studies have demonstrated that some reward circuitry regions that are associated with appetite-regulatory hormones are also involved in the development and maintenance of OB. Prader–Willi syndrome (PWS), characterized by hyperphagia and hyperghrelinemia reflecting multi-system dysfunction in inhibitory and satiety mechanisms, serves as an extreme model of genetic OB. Simple (non-PWS) OB represents an OB-control state. This study investigated subcortical food motivation circuitry and prefrontal inhibitory circuitry functioning in response to food stimuli before and after eating in individuals with PWS compared with OB. We hypothesized that groups would differ in limbic regions (that is, hypothalamus, amygdala) and prefrontal regions associated with cognitive control (that is, dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC) after eating. A total of 14 individuals with PWS, 14 BMI- and age-matched individuals with OB, and 15 age-matched healthy-weight controls viewed food and non-food images while undergoing functional MRI before (pre-meal) and after (post-meal) eating. Using SPM8, group contrasts were tested for hypothesized regions: hypothalamus, nucleus accumbens (NAc), amygdala, hippocampus, OFC, medial PFC and DLPFC. Compared with OB and HWC, PWS demonstrated higher activity in reward/limbic regions (NAc, amygdala) and lower activity in the hypothalamus and hippocampus in response to food (vs non-food) images pre-meal. Post meal, PWS exhibited higher subcortical activation (hypothalamus, amygdala, hippocampus) compared with OB and HWC. OB showed significantly higher activity versus PWS and HWC in cortical regions (DLPFC, OFC) associated with inhibitory control. In PWS, compared with OB per se, results suggest hyperactivations in subcortical reward circuitry and hypoactivations in cortical inhibitory regions after eating, which provides evidence of neural substrates associated with variable abnormal food motivation phenotypes in PWS and simple OB.
Segmentation of Brain MR Images Using a Charged Fluid Model

In this paper, we developed a new deformable model, the charged fluid model (CFM), that uses the simulation of a charged fluid to segment anatomic structures in magnetic resonance (MR) images of the brain. Conceptually, the charged fluid behaves like a liquid such that it flows through and around different obstacles. The simulation evolves in two steps governed by Poisson's equation. The first step distributes the elements of the charged fluid within the propagating interface until an electrostatic equilibrium is achieved. The second step advances the propagating front of the charged fluid such that it deforms into a new shape in response to the image gradient. This approach required no prior knowledge of anatomic structures, required the use of only one parameter, and provided subpixel precision in the region of interest. We demonstrated the performance of this new algorithm in the segmentation of anatomic structures on simulated and real brain MR images of different subjects. The CFM was compared to the level-set-based methods [Caselles et al. (1993) and Malladi etal. (1995)] in segmenting difficult objects in a variety of brain MR images. The experimental results in different types of MR images indicate that the CFM algorithm achieves good segmentation results and is of potential value in brain image processing applications.
Hip abductor muscle activity as subjects with hip prostheses walk with different methods of using a cane

Background and Purpose. Using a cane held contralateral to a prosthetic hip is presumed to be an effective way to reduce the demands on the hip abductor (HA) muscles and, therefore, the forces on the implant. In this study, surface electromyographic (EMG) activity was measured from the HA muscles to test this notion. Subjects. Twenty-four active subjects (9 female, 15 male) with unilateral prosthetic hips were tested. The subjects, aged 40 to 86 years (X=63.3, SD=10.7), were not regular cane users. Methods. Surface EMG activity and cane force were analyzed while the subjects walked with the cane held (1) contralateral to the prosthesis (CL-CANE), (2) ipsilateral to the prosthesis (IL-CANE), and (3) contralateral to the prosthesis with instructions for the subject to push with a “near-maximal effort“ (CL-CANE +). Results. Only the following conditions showed a change in HA muscle EMG activity as compared with not using a cane: CL-CANE=−31.1%, CL-CANE+=−42.3 %. Conclusion and Discussion. Holding the cane contralateral to the prosthetic hip appears to be an effective method of reducing demands on the HA muscles.
Improvement in Exercise Capacity after Nocturnal Positive Pressure Ventilation and Tracheostomy in a Postpoliomyelitis Patient

Progressive neuromuscular symptoms years after recovery from acute paralytic poliomyelitis have been termed the PPS. We describe a 52-year-old man who contracted poliomyelitis at age 9 years who fully recovered and 33 years later developed progressive dyspnea. Neurologic evaluation revealed bilateral paralysis of the vocal cords, generalized weakness, and accentuated mouth occlusion pressure and ventilatory responses to hypercapnic, hyperoxic breathing. An EMG and muscle biopsy showed changes consistent with acute and chronic denervation. Cardiopulmonary exercise evaluation demonstrated a pulmonary mechanical limit with excessive ventilation relative to CO2 output. Tracheostomy and nocturnal positive pressure ventilation resulted in increased respiratory muscle strength, normalization of ventilatory drive and marked improvement in exercise capacity.
Poster: RealDance: An exploration of 3D spatial interfaces for dancing games

We present RealDance, a prototype video game for exploring spatial 3D interaction for dance-based gaming and instruction. Our interface uses four Nintendo Wii remotes and is independent of buttons, floor position, cameras, or sensor bars so the user is untethered, allowing for natural, full-body motion. Our range of detectable movements includes stationary poses, punches, kicks, claps and stomps, which are scored in the context of the dance routine. We describe our initial experiments in interface design, gesture evaluation and scoring, and user experience, which reveals interesting new areas for 3D spatial interaction research related to creating an ‘ideal’ dance game.
Changes in forest structure of a mixed conifer forest, southwestern Colorado, USA.

We selected a warm/dry mixed conifer forest (ponderosa pine, white fir, Douglas-fir, and aspen) in southwestern Colorado to reconstruct historical conditions of fire regime and forest structure in preparation for an experiment in ecological restoration. Although mixed conifer forests are of high ecological and social value in the Southwest, they have been less studied than ponderosa pine forests. Fire-scar analysis on a 150-ha area showed recurring fires at mean intervals of 24 years (all fires with minimum of 2 sample trees scarred) to 32 years (fire scarring 25% or more of sample trees) from the 16th century until the abrupt cessation of fire after 1868, concurrent with European settlement. There was no evidence in age or species-specific data of severe burning at the scale of the study blocks (approximately 200 ha). The forest remained unharvested throughout most of the 20th century, until a cut in the early 1990s removed approximately equal basal areas of ponderosa pine and white fir. Forest structure had already changed substantially, however. Total basal area increased from an average of 11 m 2 ha 1 in 1870 to 27 m 2 ha 1 in 2003, despite harvesting of at least 8.4 m 2 ha 1 . Ponderosa pine declined from representing nearly two-thirds of basal area in 1870 to one-third in 2003. The other species increased
Social Support and Children's and Adolescents' Adaptation to Sexual Abuse

Limited research exists examining factors mitigating the negative effects of sexual abuse. This report, based on a sample of 154 participants, analyzes how social support helps explain variations in child and adolescent psychological distress at the time of sexual abuse discovery. Adolescents, compared to children, are less likely to feel supported by parents and other adult relatives, but are more likely to view friends as support resources. As expected, support from a parent is related to less psychological distress, while the use of primarily friends for support is related to increased adjustment difficulties. The findings indicate that developmental period and source of support are important to consider in understanding how support functions as a protective factor.
Middle Grades Literacy Coaching from the Coach’s Perspective

This qualitative case study investigated middle grades literacy coaches’ perspectives on their efforts to facilitate teacher change and impact classroom practice. Data were collected from three coaches as they worked with a variety of teachers in middle school settings, using field observation and interviews with coaches, teachers, and principals. Results suggest literacy coaches perceive the potential to effect positive teacher change but that they acknowledge challenges in building relationships with teachers, working within complex school structures to find time to do coaching work, and reaching across subject areas to facilitate teacher discussions of literacy instruction and student learning.
Some markers of mirroring appear intact in schizophrenia: evidence from mu suppression.

Although schizophrenia is associated with impair- ments in social cognition, the scope and neural correlates of these disturbances are largely unknown. In this study, we investigated whether schizophrenia patients show impaired functioning of the mirror neuron system (MNS), as indexed by electroencephalographic (EEG) mu (8-13 Hz) suppres- sion, a hypothesized biomarker of MNS activity that is sensi- tive to the degree of social interaction depicted in visual stimuli. A total of 32 outpatients and 26 healthy controls completed an EEG paradigm that included six action obser- vation or execution conditions that differed in their degrees of social interaction. Participants also completed a validated empathy questionnaire. Across both groups, we found a sig- nificant linear increase in mu suppression across the condi- tions involving greater levels of social engagement and inter- action, but no significant group or interaction effects. Patients self-reported diminished empathic concern and perspective taking, which showed some moderate relations to mu sup- pression levels. Thus, the schizophrenia group showed gener- ally intact modulation of MNS functioning at the electrophys- iological level, despite self-reporting empathic disturbances. The disturbances commonly seen on self-report, performance, and neuroimaging measures of mentalizing in schizophrenia may largely reflect difficulties with higher-level inferential processes about others' emotions, rather than a basic incapac- ity to share in these experiences.
Iterative vs. a directive method for solving fourth order elliptic difference equations

We compare a block successive overrelaxation method (BSOR) with a direct method for solving difference equations derived from fourth order elliptic partial differential equations. The direct method appears to be competitive in time and accuracy for a general problem.
Molecular modeling studies of IC barrier concerns

An important issue for reliability deals with migration of copper in IC structures. As line dimensions shrink and as porous materials are developed as dielectric materials, the danger of failure due to copper migration increases. This study was conducted to look at various aspects of reliability that affect copper migration. Two aspects of barrier materials were studied. Due to the link to interfacial failure, aspects of metal barrier adhesion were studied to determine whether molecular models might be used to predict and guide material choices. In addition, migration tendencies through materials were modeled to determine if material schemes might inhibit migration on the dielectric side.
Permeability to albumin in isolated coronary venules.

This study reports measurements of albumin permeability in isolated coronary venules. The isolated microvessel technique allows the quantification of transmural exchange of macromolecules under tightly controlled physical and chemical conditions. Transvenular exchange of albumin was studied in isolated coronary venules during alterations in filtration rate caused by changes in intravascular pressure. The apparent permeability coefficient of albumin (Pa) at an intraluminal pressure of 11 cmH2O was 3.92 +/- 0.43 x 10(-6) cm/s. Elevating intraluminal pressure to 16 and 21 cmH2O increased Pa to 5.13 +/- 0.57 x 10(-6) and 6.78 +/- 0.66 x 10(-6) cm/s, respectively. Calculation of the true diffusive permeability coefficient of albumin (Pd) at zero filtration rate was 1.54 x 10(-6) cm/s. The product of hydraulic conductance (Lp) and (1 - sigma), where sigma is the solute reflection coefficient, was 3.25 x 10(-7) cm.s-1 x cmH2O-1. At a net filtration pressure of 4-5 cmH2O, diffusion accounts for > 60% of total albumin transport across the venular wall. Transmural albumin flux is very sensitive to filtration rate, rising 6.7% for each cmH2O elevation of net filtration pressure. At 11 cmH2O net filtration pressure, convection accounts for nearly 70% of net albumin extravasation from the venular lumen. We suggest that the isolated coronary venule is a suitable preparation for the study of solute exchange in the heart.
Power-Associative Malcev-Admissible Algebras

The main effort in Chapter 1 was to determine flexible algebras A according to the given structures of the attached minus algebras A− when A− is a Lie or Malcev algebra. In this chapter, we determine all power-associative algebras A when A− is isomorphic to the attached minus algebra of the n × n matrix algebra, an octonion algebra, or to a finite-dimensional split semisimple Malcev algebra. This problem has been motivated by some recent works in particle physics. Eder [1, 2] used a power-associative product defined on the real associative enveloping algebra of spin 1/2, 1, or 3/2 matrices. The assumption of power-associativity in this work was necessary to have a well-defined notion of the exponential of a spin matrix and to measure a deviation from the standard spin theory. The power-associative product used in Eder’s spin theory satisfies the additional hypothesis that the Lie product under the new product remains unchanged. It appears that extensions of Eder’s work are likely to require other power-associative products defined on n × n matrices for arbitrary n. In a different point of view, Okubo [6,10] has attempted to use flexible Lie-admissible algebras A to generalize the Heisenberg equation whose solutions require the underlying algebra A to be power-associative. Power-associative products defined on octonions might suggest similar extensions of the octonionic quantum mechanics. The results in this chapter also generalize earlier works by Weiner [1,2], Okubo and Myung [2,3], Benkart and Osborn [1], and include the para-octonion and pseudo-octonion algebras introduced by Okubo [5] and Okubo and Myung [2].
Oral contraceptives and neoplasia: 1987 update

This article reviews the research evidence on the relationship between oral contraceptives (OCs) and neoplasia. More recent epidemiologic studies in this area are considered to have greater validity than earlier studies largely because of improved assessment of confounding factors. Encouraging has been the finding of a protective effect of OCs on endometrial and ovarian neoplasia: about 2000 cases of endometrial cancer and 1700 cases of ovarian cancer are averted in the US each year as a result of OC use. No consistent association either adverse or beneficial has emerged between OCs and breast cancer; however high-dose combined OCs exert a protective effect on the development of benign breast disease after 2 years of use. Longterm combined OC use appears to be related to the development of benign liver lesions but the research evidence on the association between OCs and hepatocellular carcinoma remains inconclusive. Of concern is the finding that longterm OC use is associated with an increased risk of cervical neoplasia. The mechanisms by which OCs might exert adverse effects on cervical epithelium are unclear.
Editorial: Best of the Hotline

AS PROMISED last issue, this is the second “Best of the Hotline” column from the SCAR Online Expert Hotline Archive. To visit the archive, go to www.scarnet.org and click on SCAR Expert Hotline Archive, register, and search the archive or submit your own question.
Glycolytic intermediates of human platelets: their separation and identification.

SummaryPresence of active degree of carbohydrate metabolism and identification and separation of some intermediates of this system has been directly demonstrated in human platelets. The use of radioactive phosphorous to determine specific activity of some fractions has yielded important additional data. Preliminary studies have indicated quantitative and qualitative alterations in carbohydrate metabolism during storage of normal platelets and particularly in platelets obtained from certain hematologic disorders, notably chronic granulocytic leukemia.
Comparison of European and American techniques for the analysis of volatile organic compounds in environmental matrices

The United States Environmental Protection Agency has promulgated methods for analysis of volatile organic compounds by purge and trap, or dynamic headspace, gas chromatography. In western Europe, where environmental analyses are less heavily regulated, static headspace is widely used. In this paper, these two approaches are compared and contrasted for use with different environmental matrices. The theoretical basis and state of application for purge and trap and headspace analysis are discussed, and data are presented on the accuracy and precision of both approaches. Data are reported on the use of headspace analysis for different aqueous matrix types with different sample preparation procedures. A new method for direct headspace analysis of soil samples is presented and compared with the EPA-approved purge and trap method.
Formation and Growth Mechanisms of Solid-Electrolyte Interphase Layers in Rechargeable Batteries

Battery technology is advancing rapidly with new materials and new chemistries; however, materials stability determining battery lifetime and safety issues constitutes the main bottleneck. Electrolyte degradation processes triggered by electron transfer reactions taking place at electrode surfaces of rechargeable batteries result in multicomponent solid-electrolyte interphase (SEI) layers, recognized as the most crucial yet less well-understood phenomena impacting battery technology. Electrons flow via tunneling from the bare surface of negative electrodes during initial battery charge causing electrolyte reduction reactions that lead to SEI nucleation, but the mechanisms for further growth beyond tunneling-allowed distances are not known. Our first-principles computational studies demonstrate that radical species are responsible for the electron transfer that allows SEI layer growth once its thickness has evolved beyond the electron tunneling regime. In addition, the composition, structure, and propertie...
Pitfalls and results of immediate angiography after off-pump coronary artery bypass grafting.

BACKGROUND We sought to determine the feasibility of off-pump coronary artery bypass grafting (OPCAB) in a consecutive series and prospectively assess the value of immediate post-operative coronary angiography. METHODS All patients referred for coronary artery bypass grafting, within a four-month period, were approached as candidates for OPCAB. All 50 OPCAB patients were studied by immediate post-operative coronary angiography. RESULTS The OPCAB procedure was feasible in 67% of patients (50/75). Five of 55 patients (9.1%) were converted to on-pump procedures, three for hemodynamic instability, and two because of deeply intramyocardial vessels. The other 20 underwent on-pump revascularization for anatomical and physiological reasons. The average age of OPCAB patients was 68.1 +/- 9.6 years; 26% were female, 74% male. Two (4%) were redo operations. Mean number of grafts was 2.9 +/- 0.8, 51 internal thoracic artery grafts (ITA), 17 radial artery grafts (RA), and 76 saphenous vein grafts (SVG). Angiographic graft patency was 90.2% for ITA, 88.2% for RA, and 96.1% for SVG. Interpretation of catheterization results was confounded by significant native and arterial graft spasm. Six of seven occluded arterial grafts and one of three SVG were probe patent at immediate reoperation (all had adequate flow by intra-operative doppler at the initial operation). Only two graft occlusions were noted in the 18 patients who did not receive protamine. The patency rate was 95.6% (131/137) when the probe patent anastomoses were excluded. Seven patients (14%) returned to the OR as a result of the catheterization findings; five to revise occluded grafts, one to improve the lie of a kinked SVG, and one to graft an intramyocardial intermediate ramus when an adjacent high diagonal was grafted instead (two of seven on-pump). All graft problems were found in the absence of hemodynamic instability or electrocardiogram changes. In-hospital mortality was 2% (1). Complications in survivors were atrial fibrillation in 12 patients (24.5%), permanent pacemaker in one (2%), endotracheal bleeding in one (2%), and take-back for bleeding in one (2%). CONCLUSIONS There were a significant number of unexpected arterial graft occlusions. The reversal of heparin and ITA spasm appeared to be contributory. All patients with occluded grafts had no signs of trouble. Interpretation of immediate post-operative catherization is difficult because of significant native vessel and graft spasm. It reliably determines patency but it's value is suspect for determination of long-term graft adequacy.