cssi/SciSciGPT-SciSciNet huggingface dataset:
Crushing of low density foams under triaxial loadings

Abstract A micromechanically accurate Al-alloy foam model of relative density of 0.08 is crushed under displacement controlled axial compression at different levels of external pressure–triaxial loading. For all pressure levels the foam initial stiff elastic response terminates into a load maximum triggering localized crushing in a band of cells. Under further compression the crushed zone spreads with the stress tracing a plateau during which coexistence of crushed and essentially undeformed zones of cells co-exist. The material returns to homogeneous deformation with increasing stress when the crushing has spread over the whole specimen. The level of external pressure tends to lower the limit stress, the stress plateau, and the rest of the response. This behavior is subsequently simulated at the continuum level using a Drucker–Prager type compressible constitutive model calibrated to a stress–strain response with a softening branch over part of the strain history (see Yang and Kyriakides [1] ). It is demonstrated that the homogenized model captures the three-regime response of the random foam. The limit stress, the plateau stress, its extent, the hardening of the densified material, and the dependence of these on external pressure are reproduced with good accuracy. Since in such homogenized models the cellular microstructure of the foam is replaced by the finite element mesh, the evolution of localization as the stress plateau is traced can differ from the corresponding events in the foam.
Allosteric Activation of PI3Kα Results in Dynamic Access to Catalytically Competent Conformations

Class I phosphoinositide-3-kinases (PI3Ks) phosphorylate PIP2 at its 3' inositol position to generate PIP3, a second messenger that influences signaling cascades regulating cellular growth, survival, and proliferation. Previous studies have suggested that PI3Kα activation involves dislodging the p85α nSH2 domain from the p110α catalytic subunit by binding activated receptor tyrosine kinases. We carried out molecular dynamics simulations to determine, mechanistically and structurally, how PI3Kα conformations are influenced by physiological effectors and the nSH2 domain. We demonstrate that changes in protein dynamics mediated by allosteric regulation significantly increase the population of catalytically competent states without changing the enzyme ground-state structure. Furthermore, we demonstrate that modulation of active-site residue interactions with enzyme substrates can reciprocally influence nSH2 domain dynamics. Together, these results suggest that dynamic allostery plays a role in populating the catalytically competent conformation of PI3Kα, and provide a key platform for the design of novel chemotherapeutic PI3Kα inhibitors.
The cause effect: the impact of corporate social responsibility advertising on cause consumer engagement behavior after brand affiliation ceases

Brands often engage in cause involvement out of a sense of social responsibility. While these associations with causes can positively impact brand equity, brand loyalty, and brand-favorable consume...
Psychology, market pressures, and pricing decisions in higher education: the case of the US private sector

We examine listed tuition and institutional aid practices within the US private sector, a sector where market pressures are relatively strong and consequently influence organizational behavior. We present a conceptual framework that highlights three psychological aspects of pricing—the price-quality heuristic, ego-expressive aspects of aid, and the silver lining effect—that can influence the attractiveness of specific pricing strategies to prospective students. We review relevant literature from psychology, marketing, and behavioral economics to illustrate that these three psychological aspects should be especially important in higher education. Furthermore, we identify pricing strategies that could position colleges and universities advantageously within market-based competition due to these aspects. The key elements of the strategy include high listed tuition, widespread institutional aid awards, and aid awards that are framed in a manner that confers distinction upon the recipient. We use data from a range of sources to describe the nuanced ways in which these pricing strategies are used within the US private sector. Our empirical analysis reveals that many schools, especially those in the middle of the prestige hierarchy, provide institutional aid to all or almost all of their incoming students, which allows them to set listed tuition prices well above the demonstrated willingness to pay of students. We also present evidence that aid awards are named in a manner that exaggerates the distinction conferred by the award. Our conclusion highlights implications of our work for students, organizations, policymakers, and future research.
Virtualization in CyberGIS Instruction: Lessons Learned Constructing a Private Cloud to Support Development and Delivery of a WebGIS Course.

Students in geographic information systems and science (GIS) require significant experience outside of spatial analysis, cartography, and other traditional geographic topics. Computer science knowl...
Perioperative pain control and tympanostomy tube outcomes.

Abstract Objective To evaluate perioperative pain management regimens as they relate to tympanostomy tube outcomes. Study design Retrospective chart review. Setting Tertiary referral children's hospital. Subjects and Methods: The medical records of patients ≤18 years old who underwent tympanostomy tube placement were reviewed for indications, perioperative pain medications, post anesthesia recovery unit (PACU) measures, and tympanostomy tube occlusion rates. Results Four hundred and fifty-five patients met inclusion criteria. Median age was 1.7 years (interquartile range: 1.2–3.3 years). Recurrent acute otitis media (n = 239, 52.5%) was the most common indication. All patients were American Society of Anesthesiologists (ASA) class 1 (n = 244, 58.1%) or 2 (n = 176, 41.9%). Fentanyl alone (n = 321, 70.6%) was the most common intraoperative analgesic administered followed by ketorolac alone (n = 40, 8.8%), and fentanyl and ketorolac together (n = 58, 12.8%). There was no significant difference in FLACC pain score at discharge and recovery time (minutes) also did not differ by intraoperative analgesia group (34.3 ± 15.2 for fentanyl; 36.2 ± 13.0 for ketorolac; 31.0 ± 12.5 for fentanyl and ketorolac together). Forty nine patients (11.6%) had an occluded tympanostomy tube at follow-up. Patients ≤1 year of age had a significantly higher risk of tube occlusion than patients >1 year of age (23.7% vs. 8.9%; p Conclusions Ketorolac is a reasonable non-narcotic alternative to fentanyl which provides equal pain control and does not increase tube occlusion rates.
Gibbs, Helmholtz, and Clausius–Clapeyron

Section 10.1 begins with a description of the treatment of energy and entropy extrema. Two phases with a single variety of constituent atoms are studied in Sect. 10.2. Minimum energy in adiabatically isolated phases is considered in Sect. 10.3, while Sect. 10.4 deals with relative size of phases, equality of energy minimum and specific internal energy of the phases. Various aspects of entropy are examined in Sects. 10.5 and 10.6. Legendre transformations and Helmholtz free energy are discussed in Sects. 10.7 and 10.8. Some of Helmholtz’ work relevant to this study is examined in Sects. 10.8.1 and 10.8.4–10.8.6. Clausius’ inequality in differential form is described in Sect. 10.8.2. Validity of the suggestion that maximum possible work that a given system, in thermal contact with a constant temperature reservoir, can possibly perform is equal to the resulting decrease in its Helmholtz free energy is checked in Sect. 10.8.3. That specific Helmholtz free energy is equal for different phases in thermodynamic equilibrium is noted in Sect. 10.8.7.
Effect of surface modification by nitrogen-containing chemicals on morphology and surface characteristics of N-doped pine bark biochars

Abstract In this study, pine bark-derived biochar was modified with melamine, urea, ammonium chloride, and ammonium nitrate to synthesize nitrogen-doped biochars. The effect of chemical modification on the extent of N-doping and surface properties were investigated. The elemental analysis suggested that melamine modified biochar samples had 4.75% nitrogen, higher than nitrogen in other modified biochars. The surface morphology and surface profile were studied with scanning electron microscopy and confocal laser scanning microscopy. X-ray photoelectron spectra showed that N-doped samples' surface nitrogen content increased to 8.3%, 3.9%, 2.3%, and 2.9% for melamine, ammonium chloride, ammonium nitrate, and urea, respectively. X-ray photoelectron spectroscopy results also revealed that among the nitrogen fractions in the N-doped biochars, melamine modified biochar has the highest percentage of pyrrolic and pyridinic nitrogen (35.2% and 36.8%, respectively) compared to others. Urea modified biochar had the highest percentage of graphitic nitrogen (26.6%). Our results suggest that application-specific nitrogen-enriched biochar can be prepared by understanding how different nitrogen precursors interact with carbon surfaces.
Toward Nonbinary Theories of Practice in Teacher Education Research

This essay argues that contemporary debates about the role of practice in teacher education run the risk of reproducing mind/body, thought/action dualisms. Absent these binaries, practice is unders...
The family’s role in sleep health

Abstract This chapter describes the specific ways in which the family unit influences the development of infant, child, and adolescent sleep patterns. Sleep health is discussed in the context of both parent practices and quality, as well as family, sociodemographic, contextual, and structural factors. In particular, factors relevant for infant sleep development include night awakenings, bedtime routines, infant temperament, sleep arrangements, household chaos, and sensitive periods for sleep health promotion. Developmental changes during adolescence that impact sleep are presented including puberty, social engagement, screen use, circadian delay, caffeine, and bedtime routines. The effects of school on adolescent sleep health are discussed in terms of multiple obligations and school start times. More distal-level factors are also examined including the role of socioeconomic status, family structure, racial disparities, discrimination, and parent workplace.
Optimisation de la capacité et de la consommation énergétique dans les réseaux maillés sans fil

Les reseaux mailles sans fil sont une solution efficace, de plus en plus mise en œuvre en tant qu’infrastructure, pour interconnecter les stations d’acces des reseaux radio. Ces reseaux doivent absorber une croissance tres forte du trafic genere par les terminaux de nouvelle generation. Cependant, l’augmentation du prix de l’energie, ainsi que les preoccupations ecologiques et sanitaires, poussent a s’interesser a la minimisation de la consommation energetique de ces reseaux. Ces travaux de these s’inscrivent dans les problematiques d’optimisation de la capacite et de la minimisation de la consommation energetique globale des reseaux radio mailles. Nous definissons la capacite d’un reseau comme la quantite de trafic que le reseau peut supporter par unite de temps. Ces travaux s’articulent autour de quatre axes. Tout d’abord, nous abordons le probleme d’amelioration de la capacite des reseaux radio mailles de type WIFI ou l’acces au medium radio se base sur le protocole d’acces CSMA/CA. Nous mettons en lumiere, les facteurs determinants qui impactent la capacite du reseau, et l’existence d’un goulot d’etranglement qui limite cette capacite du reseau. Ensuite, nous proposons une architecture de communication basee sur l’utilisation conjointe de CSMA/CA et de TDMA afin de resoudre ce probleme de goulot d’etranglement. Dans la deuxieme partie de cette these, nous nous interessons aux reseaux mailles sans fil bases sur un partage des ressources temps-frequence. Afin de calculer des bornes theoriques sur les performances du reseau, nous developpons des modeles d’optimisation bases sur la programmation lineaire et la technique de generation de colonnes. Ces modeles d’optimisation integrent un modele d’interference SINR avec controle de puissance continue et variation de taux de transmission. Ils permettent, en particulier, de calculer une configuration optimale du reseau qui maximise la capacite ou minimise la consommation d’energie. Ensuite, dans le troisieme axe de recherche, nous etudions en detail le compromis entre la capacite du reseau et la consommation energetique. Nous mettons en evidence plusieurs resultats d’ingenierie necessaires pour un fonctionnement optimal d’un reseau maille sans fil. Enfin, nous nous focalisons sur les reseaux cellulaires heterogenes. Nous proposons des outils d’optimisation calculant une configuration optimale des stations de base qui maximise la capacite du reseau avec une consommation efficace d’energie. Ensuite, afin d’economiser l’energie, nous proposons une heuristique calculant un ordonnancement des stations et leur mise en mode d’endormissement partiel selon deux strategies differentes, nommees LAFS et MAFS.
Thermal Diffusivity Measurement for Titanium Thin Films on Copper Substrate by Laser Produced Plasmas

The transport properties of condensed phase materials are, in principle, dependent on the local structure and composition of the specimen. This is particularly evident near the free surface of a solid alloy specimen where the morphology, composition, and thermal diffusivity exhibit significant depth dependence, as demonstrated in an earlier study of the depth-resolved thermal diffusivity of a galvanized steel specimen. A new non-contact method was used, based on time-resolved, spectroscopic measurement of the total mass removed from the specimen surface representatively in elemental composition by a high-power laser pulse. A new study of a titanium thin film of varying thickness deposited on a copper substrate is presented. The titanium thin film is first fabricated in a vacuum and then immediately analyzed for composition and thermophysical properties in situ, both by the method of representative laser-produced plasmas (LPP). Successive ablation layers of the thin film, as exposed by LPP ablation, have revealed the dependence of the thermophysical properties on film thickness as well as on depth. The existence of a characteristic length over which the substrate influences the dynamics of thermal transport in the titanium thin film has also been observed.
An Investigation of Software Scaffolds Supporting Modeling Practices

Modeling of complex systems and phenomena is of value in science learning and is increasingly emphasised as an important component of science teaching and learning. Modeling engages learners in desired pedagogical activities. These activities include practices such as planning, building, testing, analysing, and critiquing. Designing realistic models is a difficult task. Computer environments allow the creation of dynamic and even more complex models. One way of bringing the design of models within reach is through the use of scaffolds. Scaffolds are intentional assistance provided to learners from a variety of sources, allowing them to complete tasks that would otherwise be out of reach. Currently, our understanding of how scaffolds in software tools assist learners is incomplete. In this paper the scaffolds designed into a dynamic modeling software tool called Model-It are assessed in terms of their ability to support learners' use of modeling practices. Four pairs of middle school students were video-taped as they used the modeling software for three hours, spread over a two week time frame. Detailed analysis of coded videotape transcripts provided evidence of the importance of scaffolds in supporting the use of modeling practices. Learners used a variety of modeling practices, the majority of which occurred in conjunction with scaffolds. The use of three tool scaffolds was assessed as directly as possible, and these scaffolds were seen to support a variety of modeling practices. An argument is made for the continued empirical validation of types and instances of tool scaffolds, and further investigation of the important role of teacher and peer scaffolding in the use of scaffolded tools.
Learning Rules from Distributed Data

In this paper a concern about the accuracy (as a function of parallelism) of a certain class of distributed learning algorithms is raised, and one proposed improvement is illustrated.We focus on learning a single model from a set of disjoint data sets, which are distributed across a set of computers. The model is a set of rules. The distributed data sets may be disjoint for any of several reasons. In our approach, the first step is to construct a rule set (model) for each of the original disjoint data sets. Then rule sets are merged until an eventual final rule set is obtained which models the aggregate data. We show that this approach compares to directly creating a rule set from the aggregate data and promises faster learning. Accuracy can drop off as the degree of parallelism increases. However, an approach has been developed to extend the degree of parallelism achieved before this problem takes over.
Fluidity of natural membranes and phosphatidylserine and ganglioside dispersions: Effects of local anesthetics, cholesterol and protein

Abstract The microviscosity of artificial lipid membranes and natural membranes was measured by the fluorescence polarization technique employing perylene as the probe. Lipid dispersions composed of brain gangliosides exhibited greater microviscosity than phosphatidylserine (268 cP vs 173 cP, at 25 °C). Incorporation of cholesterol (30–50%) increased the microviscosity of lipid phases by 200–500 cP. Cholesterol's effect on membrane fluidity was completely reversed by digitonin but not by amphotericin B. Incorporation of membrane proteins into lipid vesicles gave varying results. Cytochrome b 5 did not alter membrane fluidity. However, myelin proteolipid produced an apparent increase in microviscosity, but this effect might be due to partitioning of perylene between lipid and protein binding sites since the latter have a higher fluorescence anisotropy than the lipid. The local anesthetics tetracaine and butacaine increased the fluidity of lipid dispersions, natural membranes and intact ascites tumor cell membranes. The effect of the anesthetics appears to be due to an increased disordering of lipid structure. The fluidity of natural membranes at the 25 °C varied as follows:polymorphonuclear leukocytes, 335 cP; bovine brain myelin, 270 cP; human erytherocyte, 180 cP; rat liver microsomes, 95 cP; rat liver mitochondria, 90 cP. In most cases the microviscosity of natural membranes reflects their cholesterol : phospholipid ratio. The natural variations in fluidity of cellular membranes probably reflect important fuctional requirements. Similarly, the effects of some drugs which alter membrane permeability may be the result of their effects on membrane fluidity.
Politics, Public Bads, and Private Information

Preferential treatment for politically influential sectors often has undesirable consequences such as increasing pollution or ecosystem degradation. Private information on firm productivity constrains the government’s ability both to redistribute income and regulate public bad production. Given political economy and information constraints, this article characterizes a social-welfare maximizing policy. The optimal policy uses a single instrument to achieve both goals, making income-support subsidies contingent upon reduction of bad outputs. Output price uncertainty works to the advantage of the government, potentially eliminating some firms’ information advantage. JEL Classification: D82, H23, Q52
The Intersection of Peremptory Challenges, Challenges for Cause, and Harmless Error

The Author provides a history and overview of peremptory challenges and their relationship with challenges for cause. Part I of the Article outlines the various types of state statutes and state case law related to the mandatory or permissive use of peremptory challenges to correct perceived error in deciding challenges for cause. Part II includes a discussion of the current law of error analysis in the federal courts and recent trends in that area of law. Part III consists of a review of the Supreme Court case law involving error analysis and peremptory challenges. This Part examines the specific situation, and the specific feature of Oklahoma law, that led to Ross. That feature is critical in limiting Ross. With that interpretation of Ross in mind, Part IV turns to the courts' responses to related situations, contrasting those interpreting Ross as a broad directive with those that limit it to its procedural posture. The Author concludes that the latter courts are correct in viewing Ross as by no means the final word in consideration of error involving peremptory challenges. The former courts fail to recognize the unique situation faced by the Ross court as laid out in Part lll; without such recognition, they fail to distinguish the cases they face from Ross. Part V concludes that Ross can and should be limited in a principled way to the context in which a state, in its peremptory challenge scheme, has chosen to impose two separate policy goals for peremptory challenges by requiring a litigant to use a peremptory challenge to preserve error in deciding a challenge for cause.
Parents’ preferences strongly influence their decisions to withhold prescribed opioids when faced with analgesic trade-off dilemmas for children: A prospective observational study

Abstract Background Despite parents' stated desire to treat pain in their children, recent studies have critiqued their underuse of prescribed analgesics to treat pain in their children after painful procedures. Parents' analgesic preferences, including their perceived importance of providing pain relief or avoiding adverse drug effects may have important implications for their analgesic decisions, yet no studies have evaluated the influence of preferences on decisions to withhold prescribed opioids for children. Objectives We prospectively explored how parents' preferences influenced decisions to withhold prescribed opioids when faced with hypothetical dilemmas and after hospital discharge. Design Prospective Observational Study Design: Phase 1 included hypothetical analgesic decisions and Phase 2, real analgesic decisions after hospital discharge. Setting Large tertiary care pediatric hospital in the Midwest of the United States. Participants Five-hundred seven parents whose children underwent a painful surgical procedure requiring an opioid prescription were included. Methods At baseline, parents completed surveys assessing their pain relief preference (i.e., their rated importance of pain relief relative to adverse drug event avoidance), preferred treatment thresholds (i.e., pain level at which they would give an opioid), adverse drug event understanding, and hypothetical trade-off decisions (i.e., scenarios presenting variable pain and adverse drug event symptoms in a child). After discharge, parents recorded all analgesics they gave their child as well as pain scores at the time of administration. Results Higher preference to provide pain relief (over avoid analgesic risk) lessened the likelihood that parents would withhold the prescribed opioid when adverse drug event symptoms were present together with high pain scores in the hypothetical scenarios. Additionally, higher preferred treatment thresholds increased the likelihood of parents withholding opioids during their hypothetical decision-making as well as at home. The strong influence of these preferences weakened the effect of opioid ADE understanding on decisions to withhold opioids when ADEs (i.e., nausea/vomiting or oversedation) were present together with high pain. Conclusions Findings from this study suggest that preferences strongly influence and may interfere with parents' effective and safe analgesic decision-making when conflicting symptoms (i.e., high pain and an ADE) are present. To improve effective analgesic use, there is a need to shape parents' preferences and improve their understanding of safe actions that will treat pain when ADE symptoms are present.
Purification of a protein from bovine plasma that binds to type 1 plasminogen activator inhibitor and prevents its interaction with extracellular matrix. Evidence that the protein is vitronectin.

Abstract Type 1 plasminogen activator inhibitor (PAI-1) binds to the extracellular matrix of cultured bovine aortic endothelial cells. Bovine plasma and bovine lung extract contain protein(s) that bind to PAI-1 and prevent this interaction. One of these proteins was purified approximately 425-fold from ammonium sulfate-fractionated plasma using standard chromatographic procedures together with affinity chromatography on PAI-1-Sepharose. The final product consisted of a major polypeptide of Mr 65,000 and two minor polypeptides of Mr 80,000 and 57,000. NH2-terminal amino acid sequence analysis of the Mr 65,000 polypeptide revealed that it was homologous with vitronectin, and antiserum against this purified binding protein recognized vitronectin and vice versa. Immunological analysis using these antisera demonstrated that the three peptides were immunologically related, and that vitronectin was present in the extracellular matrix of bovine endothelial cells and also in bovine lung.
Grain boundaries of nanocrystalline materials - their widths, compositions, and internal structures

Nanocrystalline materials contain many atoms at and near grain boundaries. Sufficient numbers of Mossbauer probe atoms can be situated in grain boundary environments to make a clear contribution to the measured Mossbauer spectrum. Three types of measurements on nanocrystalline materials are reported here, all using Mossbauer spectrometry in conjunction with X-ray diffractometry, transmission electron microscopy, or small angle neutron scattering. By measuring the fraction of atoms contributing to the grain boundary component in a Mossbauer spectrum, and by knowing the grain size of the material, it is possible to deduce the average width of grain boundaries in metallic alloys. It is found that these widths are approximately 0.5 nm for fcc alloys and slightly larger than 1.0 nm for bcc alloys.
A multi-objective mixed-discrete particle swarm optimization with multi-domain diversity preservation

Among population-based optimization algorithms guided by meta-heuristics, Particle Swarm Optimization (PSO) has gained significant popularity in the past two decades, particularly due to its ease of implementation and fast convergence capabilities. This paper seeks to translate the beneficial features of PSO from solving typical continuous single-objective problems to solving multi-objective mixed-discrete problems, which is relatively a new ground for PSO application. The original Mixed-Discrete PSO (MDPSO) algorithm, which included an exclusive diversity preservation technique to significantly mitigate premature particle clustering, has been shown to be a powerful single-objective solver for highly constrained MINLP problems. This papers makes fundamental advancements to MDPSO, enabling it to solve complex multi-objective problems with mixed-discrete design variables. Specifically, in the velocity update equation for any particle, the explorative term is modified to point towards a stochastically selected non-dominated solution at that iteration ? thereby adopting the concept of multi-leader swarms. The fractional domain in the diversity preservation technique, which was previously defined in terms of the best global particle, is now formulated as a function of the extreme members in the set of intermediate Pareto optimal solutions. With this advancement, diversity preservation not only mitigates premature particle stagnation, but also promotes more uniform coverage of the Pareto frontier. The multi-objective MDPSO algorithm is tested using a set of benchmark problems and a wind farm layout optimization problem. To illustrate the competitive benefits of the new MO-MDPSO algorithm, the results are compared with those given by other popular multi-objective solvers such as NSGA-II and SPEA.
Orthodontists' assessment and management of patient compliance

This study was designed to evaluate the use of predictors and methods of improving patient compliance. A survey of 118 items was developed by searching the literature for items that other researchers have found to be significant. The new questionnaire contained six sections. Sections 1 and 2 pertained to predictors of patient compliance; sections 3 and 4 related to methods of improving compliance. In section 5, the respondents were asked to evaluate patient personality traits that might be important in evaluating compliance, and in the last section, demographic background information on the respondents was collected. Questionnaires were mailed to 1,262 practicing orthodontists in the United States, and 429 responses were received. Patient-related items, such as desire for treatment and relationship with parents, were ranked as important factors motivating patients to comply. Verbal praise and communication were rated as important methods for improving compliance. Personality traits that orthodontists found to be predictive of patient compliance were: high self-esteem; obedient; accommodating; and self-confident. Patients' perceptions of their malocclusions, combined with their desire for orthodontic treatment, may be good indicators of compliance. Doctor-patient rapport and verbal praise may be useful ways to improve compliance.
Inferring upper-mantle structure by full waveform tomography with the spectral element method

SUMMARY Mapping the elastic and anelastic structure of the Earth's mantle is crucial for understanding the temperature, composition and dynamics of our planet. In the past quarter century, global tomography based on ray theory and first-order perturbation methods has imaged long-wavelength elastic velocity heterogeneities of the Earth's mantle. However, the approximate techniques upon which global tomographers have traditionally relied become inadequate when dealing with crustal structure, as well as short-wavelength or large amplitude mantle heterogeneity. The spectral element method, on the other hand, permits accurate calculation of wave propagation through highly heterogeneous structures, and is computationally economical when coupled with a normal mode solution and applied to a restricted region of the Earth such as the upper mantle (SEM). Importantly, SEM allows a dramatic improvement in accounting for the effects of crustal structure. Here, we develop and apply a new hybrid method of tomography, which allows us to leverage the accuracy of SEM to model fundamental and higher-mode long period (>60 s) waveforms. We then present the first global model of upper-mantle velocity and radial anisotropy developed using SEM. Our model, SEMum, confirms that the long-wavelength mantle structure imaged using approximate semi-analytic techniques is robust and representative of the Earth's true structure. Furthermore, it reveals structures in the upper mantle that were not clearly seen in previous global tomographic models. We show that SEMum favourably compares to and rivals the resolving power of continental-scale studies. This new hybrid approach to tomography can be applied to a larger and higher-frequency data set in order to gain new insights into the structure of the lower mantle and more robustly map seismic structure at the regional and smaller scales.
Several narrowband matching networks for quasi-TEM coupled microstrip lines

For multiconductor transmission line (MTL) systems, "matching" occurs in the context of multiple propagating modes and requires minimization of the reflection coefficient matrix function, one of the governing MTL longitudinal immittance matrix functions (LIMFs). This paper presents the synthesis of several matching strategies (stubs, reactances, transformers) for symmetric, coupled-line microstrip structures mismatched with several simple passive terminations. Optimization of matching network parameters yields significant reflection reduction resulting from the termination mismatches. Measurement of synthesized structures verifies the reflection reduction and power savings. General n-coupled line applications include coupled-microstrip transistor amplifiers, optoelectronics packaging, chip- and package-level interconnections, and parallel data buses.
How Teens Become Engaged in Youth Development Programs: The Process of Motivational Change in a Civic Activism Organization

The question of how youth become engaged or motivated is vital to youth development programs, because engagement influences not only program retention but the likelihood of youth gaining the benefits that programs offer. This article reports on an in-depth study aimed at generating grounded theory about the change process through which youth who are initially disengaged become motivated by program activities. Youth in a civic activism program were interviewed over a 4-month period and qualitative analyses were used to derive a model of this change process. This process was found to proceed from the youth forming a personal connection to the program’s mission to becoming intrinsically motivated by work on program activities. The analyses suggested that peers and the adult leader played important roles in supporting motivational change at each stage. The model developed from the investigation draws on existing theories of motivation.
Resonantly-Enhanced And Alloy-Assisted Photoluminescence, Band-Gap Narrowing And Stimulated Emission In A1 x Ga 1_x As

Time-resolved photoluminescence is used to study the influence of enhanced intervalley scattering and band mixing on the dynamics of dense electron-hole plasmas created by intense picosecond excitation of Alx Ga1_x As samples with Al concentrations near the direct-to-indirect band gap crossover value. Long-wave-vector scattering in these materials is enhanced by the near-degeneracy of the direct and indirect conduction-band valleys and by the alloy disorder. The relaxation of strict translational symmetry caused by this strong scattering allows the observation of indirect spontaneous emission that is comparable in strength to the direct emission, of zero-phonon indirect transitions, and of stimulated emission from the indirect band gap. Moreover, the strong mixing of the states in the direct and indirect conduction band valleys arising from this scattering causes enhanced band-gap renormalization in nominally direct-gap materials.
Progressive damage assessment of centrally notched composite specimens in fatigue

Abstract The aim of this study is to assess the residual properties and the corresponding damage states within centrally notched quasi-isotropic [0/−45/+45/90]S T650/F584 (Hexcel) carbon-fiber/epoxy composites subjected to fatigue loading using Digital Image Correlation (DIC), radiography, and a non-contact vibration measurement technique. Quasi-static tests were performed on virgin samples using DIC to determine the full-field in-plane strains at different applied load levels. Fatigue tests were interrupted during the fatigue lifetimes in order to perform quasi-static tests with DIC measurements. Non-contact vibration measurements were performed to investigate the effect of fatigue damage on residual frequency responses. X-ray computed tomography was used to determine the type, location, and extent of fatigue damage development. The results provide an important step in the validation of DIC and vibration response as a powerful combined non-destructive evaluation tool for monitoring the development of fatigue damage as well as predicting the damage level of notched composite materials.
Reactions of zirconium amide amidinates with dioxygen. Observation of an unusual peroxo intermediate in the formation of oxo compounds

Reaction of d0 Zr(NMe2)2[MeC(NiPr)2]2 (1) with O2 at −30 °C gives three Zr containing products: a peroxo trimer {(μ-η2:η2-O2)Zr[MeC(NiPr)2]2}3 (2), an oxo dimer {(μ-O)Zr[MeC(NiPr)2]2}2 (3), and an oxo polymer {(μ-O)Zr[MeC(NiPr)2]2}n (4). 2 is a rarely observed peroxo complex from the reaction of a d0 complex with O2.
Noise and timing jitter in active and hybrid mode-locked semiconductor lasers

Summary form only given. We present a comprehensive model for the noise in active and hybrid mode-locked semiconductor lasers. The model includes the effects of gain dispersion, carrier density and accompanying refractive index fluctuations, dynamic gain and loss saturation, and the laser /spl alpha/-parameter on the amplitude, phase, frequency, and the timing fluctuations of mode-locked laser pulses. Noise contributions from spontaneous emission, photon loss, carrier generation and recombination, and from the jitter in the RF drive are included in the model. The model is completely self-consistent and, to the authors' knowledge, a first detailed presentation of the relative contribution of the various noise sources to the noise of the mode-locked pulses.
Translation of human immune interferon messenger RNA in Xenopus laevis oocytes

Summary Stimulation of human leukocytes in vitro with the mitogen, staphylococcal enterotoxin A, results in highly variable quantities of interferon. Of the 37 cultures tested, approximately 30% did not produce detectable γ-interferon, and about 30% synthesized significant quantities (>100 Units ml −1 ). Messenger RNA isolated from the cells of selected donors 48 to 72 hours after mitogenic stimulation gave rise to functional γ-interferon when translated in Xenopus laevis oocytes. The mRNA coding for γ-IFN is the largest interferon mRNA so far encountered in human cells, sedimenting at 18S in formamide-sucrose density gradients. Relative to the cytoplasmic polyadenylated RNA obtained from the entire leukocyte population, the level of γ-interferon mRNA on a molecular basis was approximately ten parts per million.
Cuanta: quantifying effects of shared on-chip resource interference for consolidated virtual machines

Workload consolidation is very attractive for cloud platforms due to several reasons including reduced infrastructure costs, lower energy consumption, and ease of management. Advances in virtualization hardware and software continue to improve resource isolation among consolidated workloads but a particular form of resource interference is yet to see a commercially widely adopted solution - the interference due to shared processor caches. Existing solutions for handling cache interference require new hardware features, extensive software changes, or reduce the achieved overall throughput. A crucial requirement for effective consolidation is to be able to predict the impact of cache interference among consolidated workloads. In this paper, we present a practical technique for predicting performance interference due to shared processor cache which works on current processor architectures and requires minimal software changes. While performance degradation can be empirically measured for a given placement of consolidated workloads, the number of possible placements grows exponentially with the number of workloads and actual measurement of degradation is thus not practical for every possible placement. Our technique predicts the degradation for any possible placement using only a linear number of measurements, and can be used to select the most efficient consolidation pattern, for required performance and resource constraints. An average prediction error of less than 4% is achieved across a wide variety of benchmark workloads, using Xen VMM on Intel Core 2 Duo and Nehalem quad-core processor platforms. We also illustrate the usefulness of our prediction technique in realizing better workload placement decisions for given performance and resource cost objectives.
H-NS regulates the Vibrio parahaemolyticus type VI secretion system 1

The marine bacterium Vibrio parahaemolyticus, a major cause of food-borne gastroenteritis, employs a type VI secretion system 1 (T6SS1), a recently discovered protein secretion system, to combat competing bacteria. Environmental signals such as temperature, salinity, cell density and surface sensing, as well as the quorum-sensing master regulator OpaR, were previously reported to regulate T6SS1 activity and expression. In this work, we set out to identify additional transcription regulators that control the tightly regulated T6SS1 activity. To this end, we determined the effect of deletions in several known virulence regulators and in two regulators encoded within the T6SS1 gene cluster on expression and secretion of the core T6SS component Hcp1 and on T6SS1-mediated anti-bacterial activity. We report that VP1391 and VP1407, transcriptional regulators encoded within the T6SS1 gene cluster, are essential for T6SS1 activity. Moreover, we found that H-NS, a bacterial histone-like nucleoid structuring protein, which mediates transcription silencing of horizontally acquired genes, serves as a repressor of T6SS1. We also show that activation of surface sensing and high salt conditions alleviate the H-NS-mediated repression. Our results shed light on the complex network of environmental signals and transcription regulators that govern the tight regulation over T6SS1 activity.
Polyunsaturated membranes are required for photosynthetic competence in a mutant of Arabidopsis

Summary High levels of polyunsaturation are characteristic of all the membranes of plant and animal cells. For example, the chloroplasts of leaf cells contain about 75–80% polyunsaturated fatty acids. For the extra-chloroplast membranes in leaf cells and the membranes of non-photosynthetic tissues, values of 60–65% are typical. We report here the production ofArabidopsisdouble mutants that contain negligible levels of polyunsaturated fatty acids. The mutants were not capable of autotrophic growth and produced extremely chlorotic cotyledons and leaves. However, on sucrose media, the double mutants were robust plants showing strong leaf and root development. These observations indicate that the vast majority of receptor-mediated and transport-related membrane functions required to sustain the organism and induce proper development are adequately supported in the absence of polyunsaturated lipids. By contrast, photosynthesis is one process that does require high levels of membrane polyunsaturation.
Biomechanical modelling of the low back during load lifting.

It is proposed that we are rapidly acquiring the means to measure a variety of human biomechanical responses during manual load lifting. The need to develop and validate more comprehensive biomechanical models of the low-back is presented. A description of the development of such a general purpose model using linear-programming methods is described. Use of EMGs of torso muscles to validate the model is discussed, along with the limitations of such approaches.
Emerging dragonfly diversity at small Rhode Island (U.S.A.) wetlands along an urbanization gradient

Natal habitat use by dragonflies was assessed on an urban to rural land-use gradient at a set of 21 wetlands, during two emergence seasons (2004, 2005). The wetlands were characterized for urbanization level by using the first factor from a principal components analysis combining chloride concentration in the wetland and percent forest in the surrounding buffer zone. Measurements of species diversity and its components (species richness and evenness) were analyzed and compared along the urbanization gradient, as were distributions of individual species. Dragonfly diversity, species richness, and evenness did not change along the urbanization gradient, so urban wetlands served as natal habitat for numerous dragonfly species. However, several individual species displayed strong relationships to the degree of urbanization, and most were more commonly found at urban sites and at sites with fish. In contrast, relatively rare species were generally found at the rural end of the gradient. These results suggest that urban wetlands can play important roles as dragonfly habitat and in dragonfly conservation efforts, but that conservation of rural wetlands is also important for some dragonfly species.
Retrospective review of carvedilol administration in 38 dogs with preclinical chronic valvular heart disease

Abstract Objectives Report the effect of carvedilol administration on clinical and echocardiographic parameters and outcome in dogs with preclinical (ACVIM Stage B) chronic valvular heart disease (CVD). Animals, materials and methods Retrospective case series of 38 client-owned dogs. Demographic, physical examination and diagnostic imaging findings, blood pressure (BP), administration details and outcome were obtained from medical records of dogs receiving carvedilol for preclinical CVD. When possible, additional follow-up information was obtained through telephone interviews with referring veterinarians and owners. Results Baseline data and follow-up were evaluated. Median and interquartile range (IQR) for age and weight were 8.6 (7.2–10.8) years and 8.5 (7.6–9.6) kg. 14/38 were male; 33/38 were Cavalier King Charles Spaniels; 33/38 had Stage B2 CVD. The initial dose of carvedilol was 0.31 (0.26–0.35) mg/kg PO twice daily. The carvedilol dose achieved following up titration was 1.11 (0.81–1.32) mg/kg twice daily. No adverse effects were recorded during up titration. Median survival for all dogs was 48.5 months with a 95% CI of 38.3–58.6. Conclusions This study suggests that carvedilol at the dose reported herein is well tolerated in small breed dogs with preclinical CVD. Prospective studies to evaluate efficacy are warranted.
Effect of anisotropic hopping on the Bose-Hubbard model phase diagram: Strong-coupling perturbation theory on a square lattice

There has been a recent resurgence of experimental efforts to quantitatively determine the phase diagram of the Bose-Hubbard model by carefully analyzing experiments with ultracold bosonic atoms on an optical lattice. In many realizations of these experiments, the hopping amplitudes are not homogeneous throughout the lattice, but instead, the lattice has an anisotropy where hopping along one direction is not exactly equal to hopping along a perpendicular direction. In this contribution, we examine how an anisotropy in the hopping matrix elements affects the Mott lobes of the Bose-Hubbard model. For weak anisotropy, we find the phase diagram is only slightly modified when expressed in terms of the average hopping, while for strong anisotropy, one expects to ultimately see dimensional crossover effects.
Design of Bio-inspired Flexible Wings for Flapping-Wing Micro-sized Air Vehicle Applications

The unmatched performance of insect flight is a motivation for bio-inspired designs of synthetic wings that can undergo large deformations in flapping flight. In this paper, we experimentally study the aerodynamic performance of a bio-inspired flexible flapping wing, which has the static load–deformation characteristics of a hawkmoth (Manduca sexta) wing, and compare it with a similar geometry rigid wing. The bio-inspired wing is designed using finite element analysis, coupled with an optimization solver, to match the static load–deflection characteristics of the synthetic wing with that of real hawkmoth wings. A flexible synthetic wing is constructed using a combination of materials (carbon, nylon and rubber) for the veins and a latex membrane. The aerodynamic performance of the synthetic deformable wing is tested on a robotic flapper, using commonly observed kinematic templates of insect flapping (and rotation). Our results show increased thrust by the flexible wing for all kinematic patterns in compari...