cssi/SciSciGPT-SciSciNet huggingface dataset:
Adiabatic and stochastic motion of charged particles in the field of a single wave

A unified treatment of particle motion in a wave field is presented both for propagation oblique to a magnetic field and propagation across a magnetic field. It is shown that both cases are related to the dynamical motion of two nonlinear coupled oscillators whose frequencies are harmonically related at some values of their actions. The oblique propagation corresponds to accidental degeneracy of the coupled oscillators for which the oscillator frequencies are functions of the action in the absence of the perturbation. The motion with perpendicular propagation corresponds to intrinsic degeneracy for which the nonlinearity occurs only in the coupling term. For the former case islands in the phase space trajectories are formed around the resonant actions with the ratio of the bounce to cyclotron frequency ΩB/Ω ∝ ɛ1/2 and the island amplitude ΔpM ∝ ɛ1/2, where e is the coupling parameter. In the latter case ΩB/Ω ∝ ɛ and ΔpM ∝ 1. For both cases coupled oscillator theory1 predicts overlap (2ΔpM/δp = l, where δp is the resonance separation) at ΩB/Ω = 1/4. With similar parameters this implies overlap at smaller coupling for accidental degeneracy, although the use of practical parameters, corresponding to real plasma waves, may reverse this situation. The importance of 2nd order resonances in leading to stochasticity is demonstrated by showing that the 2nd order islands are exponentially small for small ΩB/Ω, but that the ratio of the 2nd order island width to their separation becomes comparable to the 1st order island ratio near overlap. The result is a nearly complete randomization of the trajectories in the phase plane near Ω B/Ω = 1/4 leading to stochasticity and heating.
Autoethnography as documentary in Iranian films and videos

In this essay I explore the place of autoethnography in recent Iranian films and videos. Anthropologists who have in past decades insisted on personal voices as ethnography, have coined the word ‘autoethnography’ as a category that engenders writing on self and society. This genre refers to a range of writing strategies from autobiography to self-reflexive stories. Authors often situate the self within society through self-narrative in socio-political contexts. Authors of autoethnography often conduct their practice across multiple social and cultural identities, exploring their different identities creatively through experimentation with technology, and through playing with different mediation styles. In what ways do these autoethnographic explorations offer a new opening for self expression and cultural critique? To what extent do they act as forms of either mediation or representation and to what extent is it a form of ‘reality’ staging? Extending the notion of autoethnography to films and videos of Iranian artists and cultural producers puts into sharp relief how autoethnography, as a genre of exploring one’s own culture, not only tells a personal story, but explores the ambiguity of story-telling and the difficulty of giving voice to one’s self and others. It frequently involves mixing genres, is often an act of political resistance (as in underground production), and is often about creating distinction in the face of social and political despair.
Dietary salt and flavor: mechanisms of taste perception and physiological controls

Abstract Maintenance of sodium levels is crucial to maintain normal physiology. Accordingly, the unique taste quality of saltiness allows animals, including humans, to identify sources of sodium in their environment. Although sodium is necessary for life and severe depletion can be fatal, most people currently face an overabundance of salt, and their excess consumption has been linked to negative health outcomes. The means by which the presence of sodium ions is converted into the sensation of salty taste is still unknown for humans. In rodents, though, saltiness depends in part on the passage of sodium ions through selective epithelial sodium channels, as well as on activation of other pathways in taste cells that are not specific for sodium ions. In addition to tasting salty, NaCl generates hedonic reactions that depend on factors such as concentration, state of need, and prior experience with severe sodium depletion. It will likely be impossible to develop a true salt substitute that tastes salty to people while lacking sodium ions. However, there may be ways to improve health outcomes by creating salty taste using less sodium than is found in pure NaCl. Such approaches will be aided by discovering the full set of events in taste buds and the brain that accompany NaCl intake. It will also be useful to confirm whether human salt intake is best modelled on the current rodent models of hormonal control of need-based salt appetite, or whether an alternate model provides a better explanation for why most people consume NaCl in excess of recommended levels.
Hazardous waste characterisation of high–density discharge lamps

This study was conducted to assess the relative hazards of used high intensity discharge lamps, based on metal analysis. The paper indicates the inherent difficulties associated with the samples and describes how this particular type of waste might be analysed. The lamps were analysed for total and soluble metals, including mercury, in order to determine inorganic persistent and bio–accumulative toxic substances. The data generated are being used to develop guidelines for the hazardous waste characterisation of these lamps in California, using California Code of Regulations, Title 22, and EPA (SW846) procedures.
Studies on polymorphonuclear leukocyte bactericidal function III: the role of extracellular matrix proteins.

Abstract We investigated the effect of the extracellular matrix proteins fibronectin (Fn) and laminin (Ln) on polymorphonuclear leukocytes (PMN) bactericidal activity. Adherence of PMN to increasing concentrations of Ln significantly increased the killing of Escherichia coli after 240 min of adherence, while fibronectin significantly increased PMN staphlacidal activity after 240 min of adherence. The addition of IL-1β and IL-8 but not TNF-α increased PMN bactericidal activity against E. coli when PMN were adhered to Ln, while TNF-α and IL-8 increased PMN bactericidal activity against Staphylococcus aureus when PMN were adhered to Ln. TNF-α increased PMN killing of E. coli when PMN were adhered to Fn, while only IL-1β increased the killing of S. aureus when PMN were adhered to FN. Anti-VLA-3 (α 3 /β 1 ) monoclonal antibodies (mAbs) inhibited the effect of Ln on PMN bactericidal activity, while anti-VLA-5 (α 5 /β 1 ) mAbs inhibited the effect of Fn on PMN bactericidal activity. Progressive cross-linkage of these two receptors led to a dose-dependent reduction in PMN bactericidal activity for both pathogens when PMN were adhered to Ln or Fn, respectively. These results demonstrate that extracellular matrix proteins ± exogenously added cytokines have the capacity to regulate PMN bactericidal activity. The signals sent by these matrix proteins to increase PMN bactericidal activity are transduced primarily via separate α subunits of the β1 integrin complex. Stimulation of these receptors might lead to potential upregulation of PMN bactericidal activity which would be potentially advantageous in vivo at sites of infection.
Large-group identity: ‘Us and them’ polarizations in the international arena

This paper focuses on ethnic, national, religious and ideological large groups. Large-group identity refers to persistent sameness of tens, hundreds of thousands or millions of individuals, most of whom will never meet during their lifetimes. Within the interactions of large groups, ‘otherness’ is very powerful and is both desirable and frightening. We can enjoy human diversity when we are not preoccupied with the pressures and anxieties associated with the repair and maintenance of our large-group identity. When certain elements of us and them psychology are combined, derivatives of massive aggression surface. Clinicians willing to take part in interdisciplinary efforts have much to offer for those who wish to resolve us and them conflicts.
Simultaneously occurring tumours within the same cerebello-pontine angle: refining literature definitions and proposal for classification

We report on an unusual case of a patient, not affected by neurofibromatosis, harbouring two radiologically spatially contiguous tumours within the same cerebello-pontine angle. Pathological findings were consistent with the diagnosis of two spatially distinct primary tumours, namely a meningioma and a schwannoma. We proposed a classification of tumours occurring at the same location consistent with the different spatial arrangement and histological nature of these conditions. The correct classification of these nosological entities will allow further more accurate evaluations of these cases in order to clarify the pathogenesis, prognosis and best treatment of each one.
Local meanings and lived experiences of citizenship: voices from a women's organization in South Korea

This article examines how urban middle-class women in contemporary Korea understand the idea of citizenship and experience it in their lives. Focusing on the discourse of citizenship narrated by members of the People's Friendship Society (PFS), a leading women's organization with local branches, the article illuminates local meanings of citizenship and how gender and class inflect women's lived experiences of it. The analysis of the citizenship discourse shows the bottom-up process in the development of citizenship as a social status that binds individuals to a community. First, the PFS women's understanding of citizenship reveals the centrality, to citizenship, of their sense of belonging to a society where their lives are intermingled with those of others. Second, there is internal class differentiation among the PFS women in terms of how they relate to the category of citizen. Third, ambiguity shared by these women in their identification with citizen is intimately connected to the normalized view of p...
Regulation and biological function of helminth-induced cytokine responses

The immunological hallmarks of infection with parasitic helminths, namely eosinophilia, mastocytosis and increased IgE synthesis, all appear to be induced by cytokines from the TH2 subset of CD4+ T cells: IgE production is stimulated by interleukin 4 (IL-4), eosinophilia by IL-5 and mastocytosis by IL-3 and IL-4. Here, Fred Finkelman and colleagues argue that the functional significance of the eosinophilia-mastocytosis-IgE axis in helminth infection is unclear and suggest that in some worm infections TH2-cell cytokines may contribute to host protection, while in others they may promote parasite survival.
A Reaction-Diffusion Model of Basic Fibroblast Growth Factor Interactions with Cell Surface Receptors

Basic fibroblast growth factor (FGF-2) is a potent an- giogenic growth factor involved in the development of diseases such as cancer, atherosclerosis, and heart and limb ischemia, as well as normal wound healing and tissue development. Despite being one of the most heavily studied angiogenic growth fac- tors, the binding kinetics and signaling pathways of FGF-2 are still incompletely understood. In this study, we address the role of the low-affinity heparan sulfate proteoglycans (HSPGs), the identity of the minimal signaling complex leading to FGF-2 ac- tivity, and the importance of FGF-2 dimerization using a mathe- matical model of FGF-2 diffusion and ligand-receptor binding. Unique model features include the degradation of internalized cell surface species, the binding of a second FGF-2 ligand to a high-affinity FGF receptor (FGFR), and the dimerization of FGF-2 ligands. All experimentally determined reaction rates and diffusivity values are scaled to 37 - C. Our model results suggest that FGF-2-induced cellular response is the result of a tempo- ral combination of triads (FGF-2/HSPG/FGFR complexes), dou- ble triads (2 FGF-2/HSPG/FGFR complexes), and FGF-2-bound HSPGs (FGF-2/HSPG complexes). Moreover, ligand dimeriza- tion is shown to potentially regulate FGF-2 activity by shifting the distribution of signaling complexes from the less stable triads to the more stable double triads.
Artinska ovata (Sellards) 1909 and Paraprisca fragilis (Sellards) 1909 (Insecta: Polyneoptera: Lemmatophoridae) Newly Reported from the Lower Permian of Noble County, Oklahoma, with Notes on Wellington Formation Lemmatophoridae

The extinct polyneopterous family Lemmatophoridae Sellards, 1909 includes eight species found in the Wellington Formation of Kansas. Tasch and Zimmerman (1962) had previously reported the presence of Lemmatophora typa Sellards, 1909, Artinska clara Sellards, 1909, and Lisca minuta Sellards, 1909, from the Oklahoma Wellington Formation. One specimen each of the species Artinska ovata (Sellards, 1909) and Paraprisca fragilis (Sellards, 1909) have been found in the Wellington Formation deposits of Noble County Oklahoma, bringing to five the number of known species of lemmatophorids common to the Oklahoma and Kansas Permian deposits.
Minimum time collision-free path planning for robotic assembly

SUMMARY Optimum path planning of manipulator arms in assembly applications involves the selection of the optimum combination of the robot control variables under the constraints imposed by the robot's physical capabilities and the condition of the working area. The present paper describes an approach based on numerical optimization techniques to plan collision-free paths, and on Taguchi parameter design methodology to optimize the control parameters of the pick-and-place operation that would yield minimum cycle time
Second king integral equations for the classical potential theory on open surfaces I: analytical apparatus

A stable second kind integral equation formulation has been developed for the Dirichlet problem for the Laplace equation in two dimensions, with the boundary conditions specified on a collection of open curves. The performance of the obtained apparatus is illustrated with several numerical examples.
Implementation of a non-zero-order joint-transform correlator by use of phase-shifting techniques.

The implementation of non-zero-order joint-transform correlators (JTC's) is presented. The zero-order spectra (i.e., the autocorrelation power spectra) are removed from the joint-transform power spectrum by use of phase-shifting techniques by which the output diffraction and input spatial domain can more efficiently be utilized. Applications of the phase-shifting techniques to both conventional JTC's and phase-transformed input JTC's (PJTC's) are discussed. Compared with the conventional JTC, the PJTC has the advantages of higher light efficiency, a better signal-to-clutter ratio, and the simplicity to realize phase shifting. We anticipate that the proposed non-zero-order JTC's should have a significant impact on the future development of more efficient JTC's.
Phase-slip-induced dissipation in an atomic Bose-Hubbard system

Phase slips and dissipation in a clean and well characterized system (ultracold atoms trapped in an optical lattice) are studied. The results clarify the role of phase slips in superfluid systems and may be of relevance for understanding dissipation in other bosonic systems. Phase-slips control dissipation in many bosonic systems, determining the critical velocity of superfluid helium1 and the generation of resistance in thin superconducting wires2. Technological interest has been largely motivated by applications involving nanoscale superconducting circuit elements, such as standards based on quantum phase-slip junctions3. Although phase slips caused by thermal fluctuations at high temperatures are well understood4, controversy remains over the role of phase slips in small-scale superconductors5—in solids, problems such as uncontrolled noise sources and disorder complicate their study and application6. Here we show that phase slips can lead to dissipation in a clean and well-characterized Bose–Hubbard system, by experimentally studying the transport of ultracold atoms trapped in an optical lattice. In contrast to previous work, we explore a low-velocity regime described by the three-dimensional Bose–Hubbard model that is unaffected by instabilities, and we measure the effect of temperature on the dissipation strength. The damping rate of atomic motion (the analogue of electrical resistance in a solid) in the confining parabolic potential is well fitted by a model that includes finite damping at zero temperature. The low-temperature behaviour is consistent with the theory of quantum tunnelling of phase slips, whereas at higher temperatures a crossover consistent with a transition to thermal activation of phase slips is evident. Motion-induced features reminiscent of vortices and vortex rings associated with phase slips are also observed in time-of-flight imaging. These results clarify the role of phase slips in superfluid systems. They may also be of relevance in understanding the source of metallic phases observed in thin films7,8, or serve as a test bed for theories of bosonic dissipation based upon variants of the Bose–Hubbard model9.
Tritium and helium effects on plastic deformation in AISI 316 stainless steel

Abstract Pronounced yield strength increases are observed in forged AISI 316 stainless steel when tritium is thermally charged into tensile specimens and allowed to decay to 3 He. The yield strength increase persists following low temperature vacuum annealing to remove the tritium. Analysis of helium precipitation by thin foil transmission electron microscopy indicates that prior to either vacuum annealling or mechanical deformation much of the helium present in the material is not in the form of imageable bubbles. However, the apparent volume of precipitate bubbles and the amount of helium included in the bubbles both increase after annealing or deformation. Several simple strengthening models are evaluated considering electron microscopy data, tensile test data and activation volumes calculated from dynamic strain rate change tests. Prior to annealing, the observed strength increases agree poorly with the model predictions. In the vacuum-annealed case, the observed strength increase agrees best with a small-bubble Orowan mechanism prediction, but the strain-hardening and activation volume data support a bubble-shearing mechanism.
Affinity Capture and Elution/Electrospray Ionization Mass Spectrometry Assay of Phosphomannomutase and Phosphomannose Isomerase for the Multiplex Analysis of Congenital Disorders of Glycosylation Types Ia and Ib

We report a new application of affinity capture-elution electrospray mass spectrometry (ACESI-MS) to assay the enzymes phosphomannomutase (PMM) and phosphomannose isomerase (PMI), which when deficient cause congenital disorders of glycosylation CDG-type Ia and type Ib, respectively. The novel feature of this mass-spectrometry-based assay is that it allows one to distinguish and quantify enzymatic products that are isomeric with their substrates that are present simultaneously in complex mixtures, such as cultured human cell homogenates. This is achieved by coupled assays in which the PMM and PMI primary products are in vitro subjected to another enzymatic reaction with yeast transketolase that changes the mass of the products to be detected by mass spectrometry. The affinity purification procedure is fully automated, and the mass spectrometric analysis is multiplexed in a fashion that is suitable for high-throughput applications.
Evaluation of soil venting application

This paper discusses performance limitations and containment removal optimization of soil venting technology when remediating a VOC contaminated site. Presented herein is a discussion of influential soil venting performance parameters such as containment volatility, mass transfer, and air permeability. The significance of these and other factors including placement of extraction and observation wells as related to site characterization, field tests and actual remediation projects is considered.
Failure modes of unidirectional carbon/epoxy composite compression specimens

Abstract The failure modes of unidirectional Hercules AS4/3501-6 carbon/epoxy composite compression specimens, tested using a standard IITRI compression test fixture, were analysed. Three distinct failure modes were identified, along with several minor variations. Observations suggest that the occurrence of a particular failure mode is highly dependent on the type of tabbing material used, the tab geometry, and subtle changes in the compression fixture gripping conditions.
Molecular and Biochemical Characterization of Two Plant Inositol Polyphosphate 6-/3-/5-Kinases

Despite the high deposition of inositol hexakisphosphate (IP6), also known as phytate or phytin, in certain plant tissues little is known at the molecular level about the pathway(s) involved in its production. In budding yeast, IP6 synthesis occurs through the sequential phosphorylation of I(1,4,5)P3 by two gene products, Ipk2 and Ipk1, a IP3/IP4 dual-specificity 6-/3-kinase and an inositol 1,3,4,5,6-pentakisphosphate 2-kinase, respectively. Here we report the identification and characterization of two inositol polyphosphate kinases from Arabidopsis thaliana, designated AtIpk2α and AtIpk2β that are encoded by distinct genes on chromosome 5 and that are ubiquitously expressed in mature tissue. The primary structures of AtIpk2α and AtIpk2β are 70% identical to each other and 12–18% identical to Ipk2s from yeast and mammals. Similar to yeast Ipk2, purified recombinant AtIpk2α and AtIpk2β have 6-/3-kinase activities that sequentially phosphorylate I(1,4,5)P3 to generate I(1,3,4,5,6)P5 predominantly via an I(1,4,5,6)P4 intermediate. While I(1,3,4,5)P4is a substrate for the plant Ipk2s, it does not appear to be a detectable product of the IP3 reaction. Additionally, we report that the plant and yeast Ipk2 have a novel 5-kinase activity toward I(1,3,4,6)P4 and I(1,2,3,4,6)P5, which would allow these proteins to participate in at least two proposed pathways in the synthesis of IP6. Heterologous expression of either plant isoform in an ipk2 mutant yeast strain restores IP4 and IP5 production in vivo and rescues its temperature-sensitive growth defects. Collectively our results provide a molecular basis for the synthesis of higher inositol polyphosphates in plants through multiple routes and indicate that the 6-/3-/5-kinase activities found in plant extracts may be encoded by the IPK2 gene class.
Analysis of nuclear RNA interference in human cells by subcellular fractionation and Argonaute loading

This protocol describes an optimized cell fractionation protocol for obtaining nuclei (or soluble and insoluble nuclear fractions) uncontaminated by cytoplasm or organelles— critical for studying nuclear RNAi or other nucleus-specific processes. RNAi is well known for its ability to regulate gene expression in the cytoplasm of mammalian cells. In mammalian cell nuclei, however, the impact of RNAi has remained more controversial. A key technical hurdle has been a lack of optimized protocols for the isolation and analysis of cell nuclei. Here we describe a simplified protocol for nuclei isolation from cultured cells that incorporates a method for obtaining nucleoplasmic and chromatin fractions and removing cytoplasmic contamination. Cell fractions can then be used to detect the presence and activity of RNAi factors in the nucleus. We include a method for investigating an early step in RNAi, Argonaute protein loading with small RNAs, which is enabled by our improved extract preparations. This protocol facilitates the characterization of nuclear RNAi, and it can be applied to the analysis of other nuclear proteins and pathways. From cellular fractionation to analysis of Argonaute loading results, this protocol takes 4–6 d to complete.
Inflammatory markers are not altered by an eight week dietary α-linolenic acid intervention in healthy abdominally obese adult males and females

Abstract Atherogenesis is thought to be mediated by local and/or systemic production of pro-inflammatory cytokines and omega-3 fatty acids have been implicated in reducing these inflammatory markers. The objective of this study was to determine the effect of an isocaloric diet supplemented with a plant-based dietary omega-3 fatty acid [α-linolenic acid (ALA)] on interleukin-6, C-reactive protein, serum amyloid A, and tumor necrosis factor-α. Subjects included healthy adult males and females (∼79% female, average age 38 years) with increased waist circumference (mean WC = 99 cm) and body mass index (mean BMI = 29.8 kg/m 2 ) who were free of chronic disease, not taking medications, and sedentary. Control subjects ( n = 24) did not to alter their habitual diet and the ALA group ( n = 27) followed an enriched ALA diet by using flaxseed oil capsules (increasing ALA to 5% of total energy intake) and lowered their dietary fat consumption by a commensurate amount. Fasting blood samples were obtained before and after the 8-week intervention. We found no significant changes in the inflammatory factors after this 8-week dietary intervention. This study suggests there are no beneficial effects of an 8-week ALA intervention on these inflammatory factors among young, healthy, overweight/obese subjects whose inflammatory factors are not significantly elevated.
XK endo B is preferentially expressed in several induced embryonic tissues during the development of Xenopus laevis.

Abstract XK endo B is a type I keratin that was originally identified by its preferential expression in the embryonic notochord of the amphibian Xenopus laevis. A peptide identical to a short region of its predicted amino acid sequence was used to generate antibodies against the XK endo B protein. This paper reports an immunocytochemical study of the spatial expression pattern of XK endo B during development. The protein was observed in the notochord and endoderm as predicted from previous RNA analysis. In addition, XK endo B was detected in the cement gland, in the pituitary, olfactory and pharyngeal pouch rudiments, and in a nonuniform distribution in the neural tube as well as the inner sensorial layer of the ectoderm. XK endo B expression is not limited to any germ layer or any particular cell type, but is nevertheless highly restricted in its distribution in the embryo. Its expression in several different embryonic tissues requiring inductive interactions for differentiation makes XK endo B a valuable tool with which to study the regulation of induced gene expression during embryogenesis.
Omega-3 Fatty Acids and Ginger in Maternal Health: Pharmacology, Efficacy, and Safety

Dietary supplements may be used by pregnant women if they perceive them to be natural and healthy products, if they are fearful of using prescription drugs, or if they are recommended by a health care provider. Usage surveys indicate that midwives feel comfortable in recommending some herbal products to their patients. There are sufficient data from randomized controlled trials on omega-3 fatty acids and ginger that their pharmacologic properties, efficacy, and safety data for specific indications in maternal health can be evaluated. Requests for information regarding these substances are likely to be encountered by health care providers who care for pregnant women. Omega-3 fatty acids benefit gestation, infant vision, and neurodevelopment, while effects on major depression in pregnancy and postpartum depression are less clear. Ginger is efficacious for nausea and vomiting in pregnancy but is limited in its safety data. Pharmacologic properties of each supplement and pathophysiology related to each indication are reviewed. It is recommended that pregnant and lactating women be advised to take an omega-3 fatty acid supplement daily, while the recommendation to use ginger is tentative and will likely be based on each practitioner's comfort level with the safety data that are presented.
Behavioral predictions based on perceptions of facial expressions of emotion

Current theory and research on the emotions have tended to overlook the importance and possible role of perception on the activation of a change in the feeling states of the individual. Consequently the interaction of the perception subsystem with the individual in a predictive or behavioral way has likewise been largely ignored by emotion researchers. Ironically other fields of research gives us some insight to the perceptual and affective processes. In this study subjects were presented with thirty different photographs of people posing in several different emotions. In addition to asking some "traditional" questions as identifying the emotion expressed or rating how strongly or well the emotions were communicated, subjects were also asked to make predictions as to how often they would either see or perform each expression. The pattern of results obtained was generally consistent with what was expected, and were important in two ways: (1) Neutral expressions were found to vary in similar ways with other effective affective expressions, implying that what we have been considering as neutral may in actuality be a lower-level interaction of affects, rather than a state of non-affect; (2) these results open the way for studies involving the process of perception, and provide a framework from which we can describe the role of the perceptual subsystem within the affect system.
Ostwald ripening in multicomponent alloys

The widespread use of second-phase dispersions in materials has stimulated the intensive study of the diffusion processes occurring in them at the last stage of a first-order phase transformation, termed Ostwald ripening or coarsening. As a result of the large surface area, the mixture is not in thermodynamic equilibrium. Relaxation of such a system is characterized by an increase in the scale size of the second phase and a decrease in the total energy. The authors analyze the coarsening process of an ensemble of particles, precipitation from a multicomponent alloy of arbitrary composition. The authors utilize the method of expansion of chemical potentials, which enables us to describe the coarsening rate through partial derivatives of the chemical potential, with respect to the mole fractions of different components. The latter can be easily calculated numerically, with the help of modern computer database programs such as ThermoCalc. The multicomponent interactions for diffusion are not considered, which implies rather special properties of the matrix of mobility coefficients.
Control of Pore Generation and Pore Size in Nanoparticles of Poly(styrene-methyl methacrylate-acrylic acid) *

Seeded emulsion polymerization of styrene-methyl methacrylate-acrylic acid onto seed latexes of monodisperse particles of poly(styrene-methyl methacrylate) was conducted with or without divinyl benzene as a crosslinking agent. Experiments revealed that almost no new particles were formed during the second stage of polymer- ization, and that the seeded latex particles obtained were almost monodisperse. An alkali-acid treatment was then applied to the seeded latex particles swollen in 2-bu- tanone. Experimental results indicated that: (1) for uncrosslinked particles, an opti- mum volume expansion of .50% is reached for a ratio of the swelling agent, 2-bu- tanone, to polymer (methyl-ethyl-ketone/polymer by weight) between 2.0 and 2.9; the volume expansion is much lower outside the above range. (2) For crosslinked particles, the particle volume expansion follows the same pattern, but with smaller values. (3) pH plays an important role in pore generation and volume expansion. Pore generation is optimized by decreasing pH to a value as low as 1.5 during acid treatment, and by keeping pH in the optimum range between 11.98 and 12.20 during alkali treatment. Based on the above observations, a discussion regarding the mechanism of pore gen- eration and particle expansion is provided. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 419 - 426, 1999
From “Across the Aisle” to “At the Table”: Geology, Ecology, and Hopes for a Sustaining World

Abstract Geologists and ecologists are increasingly engaged in common forums to discuss earth resource projections, environmental policy, and the concept of sustainable development. A 1998 American Association of Petroleum Geologists Division of Environmental Geology meeting led to new conversations between these groups about human population growth, the biodiversity crisis, and the prospect of global warming. Different perspectives on these phenomena may result from three factors: 1) geologists are more accustomed to certainty, as energy and mineral targets tend to be fixed in place over human time scales, whereas biological entities are not; 2) geologists are most familiar with curvilinear forecasting of substitutable reserves, whereas ecologists are becoming especially concerned with species-specific thresholds and chaos theory; and 3) both groups of scientists debate the meaning of “sustainability.” An evaluation of human population data yields a standing-room-only condition on land areas in just 674 years, a mere one-third of the Christian era. Biodiversity is not known to an order of magnitude, yet humans are driving a mass extinction event at rates 1000-10,000 times greater than background. Global warming science is limited by the unavailability of a “second Earth” to directly experiment on, forcing reliance on models that inherently involve approximations, simplifications, and assumptions upon which reasonable people will differ. “Analytic deliberation” is one new method of making environmental policy decisions, as geologists and ecologists increasingly accept participation in larger social forums.
A Gestalt-Guided Heuristic Boundary Follower for X-Ray Images of Lung Nodules

A ``piecewise heuristic'' follower of the boundaries of difficult-to-notice nonoverlapping blobs in digitized images is described. The technique was tested on 324 X-ray images of candidate lung nodules from eight radiographs with good results. This technique is several times faster than earlier detectors of the boundaries of lung nodules, while maintaining good fidelity of the detected boundaries.
Reaching informed agreement in multispecialist cooperation

Very often, complex decisions must be made by a group of specialists rather than a single decision maker. To make an effective decision, the combination of the group's expertise must be brought to bear on the situation. Fusing expertise where individuals have very detailed knowledge in their own areas and much weaker understanding of others is characterized by many difficulties: (1) agents cannot communicate their expertise in an intelligible way to nonexperts because of differences in vocabulary and conceptual content; (2) the process allows for incorrect inferences; and (3) no one knows what anyone else needs to know. This impasse cannot be broken until shared mental models are developed to provide a level of agreement in evaluating alternatives needed to focus the activity of the group. This article presents a model of decision making by teams of specialists in which agents' evaluations confound expert and naive inferences in judging alternatives. A partitioning of agent knowledge into expert and naive models is proposed. The naive portion of agents' models provides both a common language and the inferential skeleton needed for the development of shared models. Communications are categorized into types of evaluation or justification based on their form and the entities they involve within the agent models. A process of model refinement is outlined, linking communications among agents to modifications of the naive/ shared portions of their models. The process of cooperative problem solving by a team of specialists is characterized as a search among alternatives in which model refinement continually alters the agents' evaluations, leading to progressively greater accuracy and more precisely directed search. The model is intended as a research tool for investigating multiagent problem solving among people and machines.
Perinatal mortality counseling program for families who experience a stillbirth

The emotional impact of a stillbirth on a family has only recently begun to be appreciated. Literature regarding the grieving process in these families has been relatively scant and does not often facilitate applied approaches. The Perinatal Mortality Counseling Program (PMCP) at Shands Teaching Hospital, Gainesville, Florida, provides crisis intervention and support for these families as well as serving a research function. This article outlines the program, including its history, composition, procedures, and research.
Generalized semi-analytical solution of advection–diffusion–reaction in finite and semi-infinite cylindrical ducts

Abstract A semi-analytical solution for the transient advection–diffusion–reaction problem within finite and semi-infinite ducts is derived. The solution allows for general radial- and time-dependent inlet/outlet conditions, complex boundary conditions on the duct wall including adsorption and decay, and arbitrary velocity profiles of the transporting fluid. The only numerical step of the solution is the inverse Laplace transform in the time variable. Therefore, the approach also produces fully analytical steady-state solutions. The solution is verified against computational fluid dynamics (CFD) simulations under various boundary conditions and velocity profiles (Newtonian and power-law), and in all cases good agreement is obtained. Although theoretically applicable to all regimes, the solution is computationally difficult at very high Peclet numbers and very early times due to numerical instabilities as a result of finite precision arithmetic of computers. A convergence analysis is conducted to delineate the boundaries of this limit for two important cases. The solution was derived using a new approach for solving two-dimensional partial differential equations (PDEs) with non-constant coefficients which parallels the Frobenius and power series methods for solving ordinary differential equations (ODEs). The approach reduces the original PDE to a single infinite-order ODE with constant coefficients. The approach is suspected to provide solutions to a large class of PDEs of this type. The solution may find applications in a number of engineering and/or biomedical fields, it can be used to verify numerical simulators, and serve as a simple and easy-to-implement alternative where access to numerical simulators is not available.
A simple method of model fitting for adoption data

Traditional models used with adoption data often make strong assumptions concerning the nature of genetic transmission and assortative mating. A simple model is presented which avoids these assumptions. The model is linearized and, thus, has the further advantage that it can be used with standard statistical packages such as LISREL or EQS. The model allows tests of the internal consistency of the data, in addition to tests of the relative strength of genetic and environmental transmission parameters. To illustrate the model, measures of general cognitive ability in parents and their 7-year-old children from the Colordo Adoption Project (CAP) were fit to the model using the LISREL program. This relatively simple model may be expanded to incorporate more complex designs involving multiple measures or siblings. Although the model will not always allow constraints on the parameter estimates in more complex models, it offers a quick, flexible method for initial exploration of adoption data.
Self-interstitial bonding configurations in GaAs and Si

The charge-state-dependent stable and low-energy metastable states of self-interstitial defects in GaAs and Si are identified via self-consistent pseudopotential calculations. An unconventional type of 〈110〉-split-interstitial configuration in which there is essentially no bonding between the split interstitials is found to play an important role in determining the ground-state properties of interstitials for several charge states. Self-interstitials in GaAs are found to be ``negative-U'' defects. They are characterized by effective U's of -0.2 eV for Ga and -0.7 eV for As interstitials. The large negative-U value for As interstitials may explain why no magnetic resonance identification of As interstitials has been achieved in GaAs.
Mandibular Advancement by Distraction Osteogenesis for Tracheostomy-Dependent Children With Severe Micrognathia

Purpose The purpose of this study was to evaluate mandibular lengthening by distraction osteogenesis (DO) to achieve decannulation of micrognathic children with “permanent” tracheostomies. Patients and Methods Using a retrospective chart review, patients were included who had 1 ) airway compromise/tracheostomy, 2 ) micrognathia, 3 ) polysomnography-documented obstructive apnea, and 4 ) mandibular advancement using DO. Excluded were 1 ) adults, 2 ) neonates without tracheostomy, and 3 ) patients with central apnea. Patient age, past medical history, age at tracheostomy, and distraction protocol were documented. Oxygen saturation, posterior airway space (in millimeters), and sella-nasion-B point (SNB) angle were recorded. The distraction protocol consisted of a latency of 48 hours and a rate of 1 mm/day. Results There were 5 children, aged 2 to 14 years, who received a tracheostomy between ages 2 and 36 months for airway obstruction. All patients underwent bilateral mandibular distraction using semiburied, unidirectional devices. The average latency was 58 hours, the rate was 1 mm/day, the duration of fixation was 40 to 60 days, and the magnitude of advancement was 23 mm. Healing was evaluated by clinical, radiologic, and ultrasound examinations. No complications were experienced. Mean follow-up was 3.2 years. Postdistraction sleep studies demonstrated no obstructive apneic events and a mean oxygen saturation of 98% (preoperative, 76%, P P Conclusions The results of this preliminary study indicate that mandibular advancement by DO is a potentially viable treatment option for tracheostomy-dependent children with upper airway obstruction secondary to micrognathia.
A numerical simulation of Newtonian and visco-elastic flow past stationary and rotating cylinders

Abstract Numerical solutions are presented for the two-dimensional flow past a circular cylinder in an infinite domain. The flow is assumed to be uniform at infinity and the cylinder is allowed to rotate with a constant angular velocity Ω. Ω is chosen to be in the range (0 to 5 W / a ) where a is the radius of the cylinder and W is the mainstream velocity at infinity. To incorporate viscoelastic properties into the flow, an implicit four-constant Oldroyd model is used, and the resulting nonlinear constitutive equations are solved in parallel with the equations of motion as a coupled set of partial differential equations. The method of solution used is a finite difference technique with block over-relaxation. The results are compared with those of other numerical computations as well as with available experimental data. In particular, consideration is given lift experienced by the cylinder and on the streamline patterns and vorticity distribution.
Simplifying biodiesel production: The direct or in situ transesterification of algal biomass

The in situ esterification/transesterification of algal biomass lipids to produce FAME for potential use as biodiesel was investigated. Commercial algal biomass was employed, containing 20.9 wt% hexane extractable oil. This consisted of 35.1 wt% free fatty acids (FFA), 18.2 wt% TAG, and 8.8 wt% MAG, accounting for 62.1% of the extractable material. Other constituents of the hexane extractable material, accounting for 37.9% of the extracts, were not further characterized. The predominant fatty acids in the oil were palmitic (42.4 wt%), oleic (30.6 wt%), linoleic (22.8 wt%), and linolenic (16.1 wt%). Small amounts of 10-keto 16:0 and 10-OH 16:0 fatty acids were also present. Statistical experimental design was employed to coordinately examine the effects of the amounts of methanol, sulfuric acid, and reaction temperature (23–65°C) on the yield of FAME in 2 h reactions. Three methods of feedstock preparation were examined – as received, oven dried, and water-washed/dried. For all feedstocks conditions could be identified which were predicted to yield greater than 90% maximum theoretical FAME production. Oven drying the feedstock reduced the amount of methanol required, with 83% of maximum yield obtained at a methanol/fatty acid molar ratio of 220:1 (4 mL methanol/g substrate). Water washing the biomass did not reduce the methanol required for high level transesterification. Practical applications: In biodiesel production by the conventional method of alkali-catalyzed transesterification of a refined vegetable oil/the combination of feedstock and process costs threatens the economic viability of biofuel production. In situ esterification/transesterification is a method for producing biodiesel wherein a lipid-bearing material is directly treated with reagents that catalyze fatty acid alkyl ester production from FFA and acylglycerols. By eliminating the need to isolate and refine the feedstock lipid, this approach to biodiesel production eliminates some of the processing steps required by contemporary methods. This could provide a welcome reduction in the cost of biodiesel production. There is presently considerable interest in the possibility of biofuel production from algal biomass. This study describes the application and optimization of in situ transesterification to a lipid-bearing algal biomass. Application of this technology could facilitate the economical production of biodiesel from algal biomass.
Honeymoon or consolidation, or both?: Time dependence of democratic durability

Much research has been done to identify factors that facilitate or prevent democratic breakdown. Little attention, however, has been paid to the question of whether and how the baseline risk level (after controlling for the impacts of relevant factors) changes over time. Using a flexible parametric survival model, I analyse the duration of 149 democratic periods (1946–2008) and demonstrate that the baseline risk has an inverted-U shape, which provides evidence for the honeymoon effect and democratic consolidation. This finding has an important policy implication for democratic assistance programmes.
Arabidopsis, a useful weed

Plants are unique in many aspects of development, cell biology, biochemistry, and physiological response. Plant cells do not migrate during morphogenesis, and totipotency of cells from many organs shows that plant development does not require maternal storage of positional information. Plant cell division is unlike that in other eukaryotes; plant cells are connected to their neighbors by unique structures (plasmodesmata) and live encased in a singular type of matrix (the cell wall). Plant biochemistry involves not only the metabolic processes familiar in animals but also several types of photosynthesis, as well as synthesis of an extraordinary range of plant-specific chemicals, many used in defense against herbivores and bacterial and fungal plant pathogens. In response to their environment, plants utilize unique pathways of light and gravity detection; in both environmental response and development they use growth substances, or hormones, quite unlike those of organisms in other kingdoms. Not only are these hormones chemically different from those in animals, but their use does not involve specific endocrine organs. Many of the most perplexing aspects of plant physiology, development, and biochemistry are now coming to be studied by the methods of classical and molecular genetics.
Airlicking vs. water drinking in a T-maze: Thirsty rats prefer water☆

Abstract This study compares the reinforcement values of drinking and airlicking in thirsty rats. What duration of airlicking is equivalent in reward value to 10 sec of drinking? Water-deprived rats were trained to lick an airstream from a standard drinking tube. They were then tested in a T-maze in which they were confronted with a choice between 10 sec of water and access to an airstream for periods of airlicking varying from 40–300 sec. All of the rats preferred the water to the airstream, regardless of the duration of the airlicking reward and irrespective of the goal positions in the maze. It is concluded that for a thirsty rat the rewarding effects of drinking water are very much greater than those of airlicking.