cssi/SciSciGPT-SciSciNet huggingface dataset:
Promoting Pretend Play in the Preschool Years: Teacher Practices and Strategies for Involving Families

Research demonstrates that creative play is critical for healthy human development. It helps children develop physical, social, and cognitive abilities and promotes problem-solving skills and creativity. Children around the world play, and the ways they play are culturally bound. Children benefit from both unstructured and structured play, and teachers and caregivers can scaffold both types of play through a variety of supportive methods. It is important to view every interaction and experience as an opportunity for learning, without providing so much structure that it interferes with the play. In this article, the authors identify the benefits of pretend play—creating imaginary scenarios—and explore ways that teachers and families can promote make-believe play for preschool children.
Semantic Closure: A Guiding Notion to Ground Artificial Life

The lack within AL of an agreed-upon notion of life and of a set of criteria for identifying life is considered. I propound a reflection upon the codified nature of the organization of living beings. The necessity of a guiding notion based on the coding is defended. After sketching some properties of the genetic code I proceed to consider the issue of functionalism as strategy for AL. Several distinctions ranging from plain multiple realizability to total implementation independence are made, arguing that the different claims should not be confused. The consideration of the semantic and intrinsically meaningful nature of the code leads to discuss the “symbol grounding” in AL. I suggest the principle of Semantic Closure as a candidate for confronting both problems inasmuch as it can be considered an accurate guiding notion to semantically ground Artificial Life.
Chapter 17 Tubular Permeability to Buffer Components as a Determinant of Net H Ion Fluxes

Publisher Summary The fundamental mechanisms of urinary acidification are bicarbonate reabsorption and formation of titratable acidity, and it is generally conceded that hydrogen ion secretion by the tubular epithelium participates in both processes. However, it has repeatedly been proposed that an additional transport mechanism could exist for the bicarbonate anion in its ionic form. This chapter provides evidence that the buffer systems exist with widely varying permeance of their acid components, varying from practically impermeant components to systems with very permeant components that appear to maintain transepithelial concentration equilibrium (glycodiazine) and that this property determines the magnitude of the H + ion flux taken up by them in the tubular lumen. The H + ion source could be related to the process of recirculation of the diffusible acid, as proposed for carbonic acid. The acid formed in the lumen by H + ion secretion would diffuse into tubular cell and there could either dissociate, yielding an H + ion to the proton pump, or neutralize OH - ions formed by the water-splitting process of a redox pump.
Panel: "Benchmarking for Real-Time High-Performance Computing"

The motivation, organization, and discussion questions for the panel session "Benchmarking for Real-Time High Pefornance Computing" are described.
The possible role of immunologic injury in the dysplastic bony lesion in LP/J mice***

An immunohistologic study was performed on temporal bones from 30 LP/J mice and 17 CBA/J mice to assess the role of immunologic injury in the pathogenesis of dysplastic bony lesions in LP/J mice. Temporal bones were harvested from animals aged 2 to 31 months to evaluate the progression of the disease. As early as 2 months of age, before the onset of bony lesions, the tympanic cavities frequently contained small effusions coating the ossicles and otic capsules that were demonstrated to contain immunoglobulins and pockets of macrophages. Later in the course of the disease, bony lesions grossly and histologically similar to human otosclerosis developed, which stained for immunoglobulins. No similar bony lesions, effusions, cellular infiltrates, or staining for immunoglobulins was detected in the control animals, even in the presence of acute otitis media. This study suggests a role of immunologic injury in the pathogenesis of dysplastic bony lesions in LP/J mice.
Comparison of Hartree−Fock, Density Functional, Møller−Plesset Perturbation, Coupled Cluster, and Configuration Interaction Methods for the Migratory Insertion of Nitric Oxide into a Cobalt−Carbon Bond

Optimized geometries at the restricted Hartree−Fock (RHF), second-order Moller−Plesset perturbation (MP2), density functional theory (DFT), and configuration interaction with singles and doubles (C...
Joint modeling of longitudinal outcomes and survival using latent growth modeling approach in a mesothelioma trial

Joint modeling of longitudinal and survival data can provide more efficient and less biased estimates of treatment effects through accounting for the associations between these two data types. Sponsors of oncology clinical trials routinely and increasingly include patient-reported outcome (PRO) instruments to evaluate the effect of treatment on symptoms, functioning, and quality of life. Known publications of these trials typically do not include jointly modeled analyses and results. We formulated several joint models based on a latent growth model for longitudinal PRO data and a Cox proportional hazards model for survival data. The longitudinal and survival components were linked through either a latent growth trajectory or shared random effects. We applied these models to data from a randomized phase III oncology clinical trial in mesothelioma. We compared the results derived under different model specifications and showed that the use of joint modeling may result in improved estimates of the overall treatment effect.
Polarization-dependent photocurrent enhancement in metamaterial-integrated quantum dot infrared detectors

We present the design, fabrication, and characterization of quantum dots-in-a-well infrared detectors integrated with a planar metamaterial layer. The resonantly excited metamaterial layer provides strongly enhanced optical fields and the increased photocurrent is obtained at the metamaterial resonant frequency.
Do Women Engage in Less Task Behavior Than Men

The overwhelming evidence from data collected in mixed-gender groups is that men originate more behaviors related to solving the task confronting the group than do women. However, efforts to detect whether men and women interact differently in same-gender task groups have produced less consistent findings. Some studies report men originating more task behavior than women, but others report no such difference in task behaviors. We examine data from an experiment in which men and women participated in a decision-making task in two types of same gender groups. In type one, no initial differentiating structure was introduced into the group prior to interaction on the task. In type two, initial differentiating structures were introduced prior to the interaction on the task. We examine the effects that these differentiating structures have on the interaction patterns in these groups, as well as the effects that the gender of the subject has on these interaction processes. Experimental results show that in type ...
Bias drift reduction in polarization-maintaining fiber gyroscope

The output signal of a birefringent fiber gyroscope is analyzed, and sources of error due to polarization cross coupling in the fiber and fiber components are identified. Techniques to suppress such errors by modulating the fiber birefringence and balancing the optical power in the two polarization modes are proposed and demonstrated.
Intermediates in melanin formation

Abstract In the oxidation of 5,6-dihydroxyindole to melanin an intermediate pigment, with absorption maximum 530 mμ, and its reduced form, with characteristic fluorescence, are shown to be the first observed intermediates and may represent a dimeric stage. The next stages have flatter absorption maxima, around 540 mμ, and no fluorescent reduced forms can be extracted by ethyl acetate; these may be oligomers intermediate between the dimer and melanin polymer.
The Influence of Attitude upon Scaling of Attitude Items

(1937). The Influence of Attitude upon Scaling of Attitude Items. The Journal of Social Psychology: Vol. 8, No. 1, pp. 39-45.
Deuterium Reveals the Dynamics of Notch Activation

Notch activation requires unfolding of a juxtamembrane negative regulatory domain (NRR). Tiyanont et al. (2011) analyzed the dynamics of NRR unfolding in the presence of EGTA. As predicted from the crystal structure and deletion analyses, the lin-Notch repeats unfold first, facilitating access by ADAM proteases. Surprisingly, the heterodimerization domain remains stable.
Trichinella spiralis: Effect of synthetic double-stranded polyribonucleotides

Abstract Administration of double-stranded synthetic polynucleotide, polyribosinic-polyribocytidylic acid [poly(I · C)] to animals sensitized once to Trichinella spiralis antigen + complete adjuvant (Difco's H37 Ra) did not affect induction or transfer of delayed hypersensitivity. Poly (I · C) did not enhance antibody production in animals sensitized only once when tested by passive cutaneous anaphylaxis (PCA). However, it appeared to enhance antibody production in hypersensitized animals. Several of the undiluted serum samples from hypersensitized animals treated with 3 mg of poly(I · C) were anaphylactogenic and inhibitory when tested by PCA, but not when serum samples were diluted 1:80. Possible reasons for these phenomena are discussed.
The design of a real-time engineering flight simulator for the rapid prototyping of avionics systems and flight control systems

This paper describes the design of a real-time flight simulator, which is based on a modular architecture of PCs coupled by Ethernet. The simulator is required to provide a rapid prototyping environment to support the design and evaluation of avionics systems and flight control systems. Methods are described to ensure real-time implementation of the equations of motions using a standard PC and the provision of real-time graphics to simulate aircraft displays using SVGA. The paper includes analysis of the performance of the flight modelling methods and the simulation of aircraft displays. The paper concludes that high fidelity flight models and aircraft displays can be implemented using standard PC platforms and Ethernet cards, if attention is given to the design of the simulator architecture. The resultant simulator provides a rapid prototyping environment, standardising on the packet format and low-level packet protocols of Ethernet,
Induced-polarization detection and mapping of contaminant plumes

Several laboratory and scaled model investigations suggest that organic contaminants affect the surface electrical properties of exposed soils/rocks and therefore produce measurable induced polarization IP signatures. However, there is little field evidence of an IP methodology for contaminant mapping. A2D time-domain IP method is developed for mapping the FS12 contaminant plume at the Massachusetts Military Reservation MMR located in Cape Cod, Massachusetts. The FS-12 plume consists of approximately 265 m 3 of fuel that erupted from a broken underground pipeline in the early 1970s. Benzene and ethylene dibromide EDB are the primary contaminants at FS-12, with concentrations exceeding the allowed maximum concentration levels MCL, while other constituents of the plume did not exceed their MCL. Therefore, the contaminants of interest are benzene and EDB, partly because of their health risk and partly because they present the highest concentrations 2400 and 1000 g/L, respectively among the plume constituents and are therefore more likely to be related to the polarization source. IP data were acquired along a survey line that partially transects the plume extending over contaminated and uncontaminated zones and were inverted to give 2D resistivity and chargeability plots to 100 m depth and a horizontal extent of 400 m. By separately inverting IP data derived from time windows located at short and long decay times, a timedomain gross spectral chargeability difference is produced. Both the chargeability and gross spectral chargeability difference show good agreement with the known location of the plume from monitoring wells, with the IP chargeability section suggesting contaminant distribution detail that cannot otherwise be inferred from the sparse borehole distribution.
Numerical solution of the viscous hypersonic flow past blunted cones at angle of attack

Hypersonic viscous flow over spherically blunted cones of large half angle is computed at small angles of attack in the plane of symmetry of the flow field. Time-dependent viscous shock-layer equations in body-oriented coordinates are used to describe the flow field. The shock wave is treated as a discontinuity, across which the Rankine-Hugoniot relations are used to compute the flow conditions behind the shock. A time-marching second-order finite-difference method is used to solve the equations for a perfect gas. The local CFL (Courant-Friedrich-Lewy) time increment is used to advance the solution in time at each grid point. A fourth-order damping is used to damp the oscillations in the flow quantities. The numerical results of the present analysis for quantities such as shock standoff distance, surface-pressure distribution, and heating rates compare well with the existing theoretical and experimental results.
Articulating a Geography of Pain: Metaphor, Memory, and Movement in Helena María Viramontes's Their Dogs Came with Them

Los Angeles is a metropolis physically interrupted by freeways and demographically fragmented into isolated pockets of race and class. The geographer Edward W. Soja describes contemporary LA as being “difficult to grasp persuasively in a temporal narrative for it generates too many conflicting images, confounding historization, always seeming to stretch laterally instead of unfolding sequentially” (Postmodern 222). Helena Maria Viramontes explores the sprawled and concurrent identities of LA using a nonlinear narrative focused on the disenfranchised residents of East Los Angeles, communicating this “difficult to grasp” urban space through the novel’s fractured narrative style and content. This article analyzes how Viramontes’s novel Their Dogs Came with Them (2007) articulates East Los Angeles through the use of imagery, memory, and movement. The first section deals with the figurative language—metaphor—that binds the characters to their environment and vice versa. The second section analyzes the theme of memory and its impermanence as it relates to the fractured nature of this city and its disruptive freeways. Finally, this article examines the “tactile apprehension,” a la Michel de Certeau’s theorizing of walking in the city, found in the different modes and velocities of transportation as concurrent but divergent modes of articulation (Practice 97). I argue that the novel presents multiple experiences of the city, which reveal not only the way the geography impacts the community it contains but also ways the Latino community can resist the erasive consequences of race and class by forming independent spatial meaning. Set in East Los Angeles during the 1960s, Their Dogs Came with Them tells the story of four female protagonists who struggle through the isolation and turbulence plaguing their community. A high school student living with her grandparents, Ermilia Zumaya undergoes a political awakening. Ana works in an office and struggles to take care of her mentally unstable brother Ben. Tranquilina, the daughter of missionaries, contemplates the role of faith in her violent surroundings. Finally, Antonia Gamboa, a young female gang member known as “Turtle,” lives on the street while passing as a male. A major source of disruption is the construction of freeways, which has led to entire neighborhoods being razed and bulldozed into oblivion. Furthermore, a Quarantine Authority, set up to protect the residents from rabid dogs, polices and regulates the movement of the community. The action of the novel moves fluidly between the past and the present with a few blank lines between paragraphs marking a leap
Teaching systems programming and software design: Problems and solutions

In this paper we consider the problem of teaching systems programming and software design. We point out some of the major faults of many courses in this area and propose a course structure and method of presentation which we feel overcomes these faults. We review our past experience in using the proposed method and point out some aspects which need further development.
The roles of gene duplication, gene conversion and positive selection in rodent Esp and Mup pheromone gene families with comparison to the Abp family.

Three proteinaceous pheromone families, the androgen-binding proteins (ABPs), the exocrine-gland secreting peptides (ESPs) and the major urinary proteins (MUPs) are encoded by large gene families in the genomes of Mus musculus and Rattus norvegicus. We studied the evolutionary histories of the Mup and Esp genes and compared them with what is known about the Abp genes. Apparently gene conversion has played little if any role in the expansion of the mouse Class A and Class B Mup genes and pseudogenes, and the rat Mups. By contrast, we found evidence of extensive gene conversion in many Esp genes although not in all of them. Our studies of selection identified at least two amino acid sites in b-sheets as having evolved under positive selection in the mouse Class A and Class B MUPs and in rat MUPs. We show that selection may have acted on the ESPs by determining Ka/Ks for Exon 3 sequences with and without the converted sequence segment. While it appears that purifying selection acted on the ESP signal peptides, the secreted portions of the ESPs probably have undergone much more rapid evolution. When the inner gene converted fragment sequences were removed, eleven Esp paralogs were present in two or more pairs with Ka/Ks .1.0 and thus we propose that positive selection is detectable by this means in at least some mouse Esp paralogs. We compare and contrast the evolutionary histories of all three mouse pheromone gene families in light of their proposed functions in mouse communication.
The effect of water on ZnCl2 and its glasses

A partir de la litterature, il a ete montre qu'au-dessus de 90°C, ZnCl 2 cristallin anhydre a P(H 2 O)=10 mm n'est pas deliquescent. Il a egalement ete montre experimentalement que lorsque H 2 O est incorpore a des verres a base ZnCl 2 , la transition vitreuse, la devitrification et la fusion se font a une temperature beaucoup plus basse. La premiere etape de la degradation d'un verre ZnCl 2 traditionnel par exposition a une faible humidite est la deliquescence, tandis que celle d'un verre ZnCl 2 sans eau est la devitrification de surface
Osteoarthritis-related biomarkers following anterior cruciate ligament injury and reconstruction: a systematic review

summary Objective: There is an increased risk of developing knee osteoarthritis (OA) following anterior cruciate ligament (ACL) injury. Biomarkers may provide diagnostic, prognostic, or burden of disease indicators of OA before radiographic changes become apparent. Unfortunately, there has been no systematic review to clarify which biomarkers may be most informative following injury. Therefore, this review critically investigated existing studies of OA-related biomarkers in ACL-deficient (ACL-D) and reconstructed (ACLR) patients to summarize the current evidence and identify knowledge gaps. Design: A systematic review of the literature in Web of Science and PubMed databases (1960eJune 2014) was performed. All English-language caseecontrol and longitudinal studies assessing OA-related biomarkers in ACL-D and ACL-R patients were considered. Data regarding biomarker changes over time within ACL-D and ACL-R patients as well as differences in ACL-D/ACL-R patients compared with a control group were extracted from pertinent studies. Results: A descriptive summary of 20 included studies was produced. In ACL-D patients compared with controls, synovial fluid biomarkers indicated elevated collagen turnover, while the inflammatory cytokine response was inconclusive. In ACL-R patients, serum concentrations indicated decreased collagen breakdown, but urine concentrations were indicative of greater collagen breakdown when compared to controls. Compared to preoperative values, the overall inflammatory cytokine response measured with synovial fluid biomarkers increased while plasma biomarkers did not change following reconstruction. Conclusion: Patients with ACL-D or ACL-R have altered biomarkers indicative of OA. More research with standardized reporting is needed to effectively determine which biomarkers are the most indicative for OA development and progression following ACL injury.
Measurement of an isosbestic point in the Raman spectrum of liquid water by use of a backscattering geometry

Measurements presented here confirm that a temperature-insensitive point occurs in the backscattered Raman spectrum from liquid water. This result, coupled with existing laboratory measurements of Raman scattering from liquid droplets, indicates that a Raman lidar measurement of cloud liquid water is feasible.
Hyponatremia in Acute Decompensated Heart Failure: Mechanisms, Prognosis, and Treatment Options

Hyponatremia is common and is increasingly recognized as an independent prognostic marker that adversely affects morbidity and mortality in various disease states, including heart failure. In acute decompensated heart failure (ADHF), the degree of hyponatremia often parallels the severity of cardiac dysfunction and is further exacerbated by any reduction in glomerular filtration rate and arginine vasopressin dysregulation. A recent study showed that even modest improvement of hyponatremia may have survival benefits. Although management of hyponatremia in ADHF has traditionally focused on improving cardiac function and fluid restriction, the magnitude of improvement of serum sodium is fairly slow and unpredictable. In this article, we discuss the mechanisms of hyponatremia in ADHF, review its evolving prognostic significance, and evaluate the efficacy of various treatments for hyponatremia, including the recently approved vasopressin receptor antagonists for managing hyponatremia among patients hospitalized for ADHF. Copyright © 2008 Wiley Periodicals, Inc. Dr. Jun Chiong is a member of the Speaker's Bureau of Otsuka Pharmaceutical company. The authors have no additional funding, financial relationships, or conflicts of interest to disclose.
MLL-AF9 Leukemia Stem Cells: Hardwired or Taking Cues from the Microenvironment?

MLL rearrangements in humans lead to both acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). While AML has been successfully produced in mice, modeling ALL has been more difficult. In this issue of Cancer Cell, Wei et al. (2008) describe generation of AML, ALL, and biphenotypic leukemia by manipulating the cytokine milieu of human progenitor cells expressing MLL-AF9. They demonstrate that both multipotent and lineage-restricted progenitors are targeted by MLL-AF9 fusion proteins and that Rac signaling is crucial for survival. This study demonstrates the heterogeneity of MLL-AF9 leukemic stem cells and the importance of the microenvironment in determining lineage outcome.
Synthesis and Characterization of New Phenylbis(salicylato)bismuth(III) Complexes

Compounds with the compositions [BiPh(Hsal)2] (1a) and [BiPh(Hsal4Me)2] (1b) were prepared by the reactions of triphenylbismuth with 2-hydroxybenzoic acid (H2sal) and 4-methyl-2-hydroxybenzoic acid...
Deformation and stress-induced transformation of polybutene-1

Abstract The deformation at room temperature of thick (ca. 2 mm) and thin (ca. 1000 A) films of polybutene was characterized by electron microscopy and electron x-ray diffraction. The thin films, as studied, draw by micronecking whereas the thick films draw uniformly. In both types of samples the details of the deformation process varied with the orientation of the lamellae in the original spherulitic structure; in all cases, however, the lamellae broke up into “mosaic” blocks prior to uniform fibril formation. The tetragonal-hexagonal phase transformation accompanying the deformation of fresh polybutene films generally appeared to occur within the blocks except in those situations in which the lamellae are being drawn perpendicular to the molecular axes, that is, parallel to the lamella surface; in the latter case the tetragonal form can be at least partially retained until unfolding and fibril formation occurs.
StandardsߞThe evidence of concern

Some writers have accused engineers of lacking proper concern for the effects of their developments on society and the environment. There are indications that many students hold this same point of view. However, the author of this article contends that such criticisms are unwarranted and offers evidence that, with the exception of the academician, engineers have shown foresight and concern for the public by developing a large number of standards to ensure product quality and safety.
Curvature Sorting of Peripheral Proteins on Solid-Supported Wavy Membranes

Cellular membrane deformation and the associated redistribution of membrane-bound proteins are important aspects of membrane function. Current model membrane approaches for studying curvature sensing are limited to positive curvatures and often require complex and delicate experimental setups. To overcome these challenges, we fabricated a wavy substrate by imposing a range of curvatures onto an adhering lipid bilayer membrane. We examined the curvature sorting of several peripheral proteins binding to the wavy membrane and observed them to partition into distinct regions of curvature. Furthermore, single-molecule imaging experiments suggested that the curvature sensing of proteins on low-curvature substrates requires cooperative interactions.
A two-stage model of visual search.

A two-stage visual search model is described. Four experiments show that in a VM paradigm sequential presentation of the display leads to increases in accuracy and decreases in latency. Slower presentation rates allow for faster transfer of the target from iconic to short-term memory. When target and background items are dissimilar, transfer to short-term memory need not take place and decisions can be made on the basis of the Stage 1 analysis. These results are taken as confirming evidence for the proposed model.
Micromechanical Properties Of Fixed And Living Vascular Pulmonary Endothelial Cells Following Exposure To Barrier Enhancing And Barrier Disrupting Agents

Disruption of pulmonary endothelial cell (EC) barrier function is a critical pathophysiologic event that occurs in multiple inflammatory disease processes. The actin cytoskeleton, an essential regulator of endothelial permeability, is a dynamic structure whose stimuli-induced rearrangement is linked to barrier modulation. We used atomic force microscopy (AFM) to characterize structural and mechanical changes in the F-actin cytoskeleton of cultured human pulmonary artery EC in response to both barrier-enhancing and barrier-disrupting conditions. The mechanical properties of both fixed and live cells were evaluated. Elastic modulus values in the range of 50-1000 kPa were typically measured for fixed cells, while much lower values of 1-40 kPa were characteristic of live cells. In fixed cells, a differential distribution of elasticity was observed after exposure to the barrier-enhancing compound S1P (sphingosine 1-phosphate) compared to that produced by the barrier-disrupting agonist, thrombin. After S1P, the elastic modulus was elevated primarily at the periphery, while thrombin treatment increased elasticity in the central region of the cell. These observations correspond with the distribution of F-actin in parallel-treated EC as detected by immunofluorescence. In living cells, thrombin generally increased the average elastic modulus over 60 minutes; however, the S1P response was more varied and subtle. Experiments are under way to confirm these preliminary observations. These results provide novel insights into the structural and mechanical properties that dynamically regulate pulmonary EC barrier function.
The effect of hypodynamic endotoxin shock on myocardial high energy phosphates in the rat

High energy phosphate concentrations were determined in the isolated perfused (in vitro) and intact (in situ) heart preparations in the rat during a control period and at various time intervals (1,2,4,8 or 16 h) following the intraperitoneal injection of 4 mg·kg−1 E coli endotoxin. Arterial glucose and lactate concentrations were determined just prior to excising the hearts. Following the induction of endotoxin shock, myocardial ATP and creatine phosphate decreased in both the in situ and in vitro preparations, while AMP increased only in the in situ group. There was no significant alteration in ADP in either group throughout the 16 h experimental period. Myocardial energy charge decreased at 1 h following endotoxin shock and remained depressed throughout the 16 h study period. Total heart weights as well as the wet/dry ratio were unaltered throughout the experiment. The reductions in ATP and creatine phosphate during endotoxin shock were a direct result of the shock state and not due to the loss of myocardial mass or the presence of oedema. One hour following the induction of endotoxin shock plasma glucose increased then returned to the control value by 2 h and remained at the pre-endotoxin level throughout the experimental protocol. Arterial lactate concentration increased following endotoxin administration and remained elevated until 16 h, where it was not different from the control value. Data from the present study clearly indicate a myocardial energy deficit during acute hypodynamic endotoxin shock in the rat and may provide a mechanism for the cardiac dysfunction normally associated with this shock paradigm.
Epicardial Atrial Pacing

A modification of the technique for placing a permanent epicardial electrode to the atrium is described. It results in long-term atrial pacing and low sensing thresholds. The method requires meticulous surgical technique but is reliable, safe, and free from serious or long-term complications.
Light and electron microscopic study of an avian pretectal nucleus, the lentiform nucleus of the mesencephalon, magnocellular division

Using several light microscopic methods we have identified the lentiform nucleus of the mesencephalon, magnocellular division, by its position in the pretectum, its cellular composition, and its complement of retinal afferents and have distinguished it from neighboring structures. At the light microscopic level large neurons (approximately 30 X 21 microns) and small neurons (approximately 13 X 9 microns), which are more numerous, are seen interspersed among myelinated axons. The large neurons are generally ovoid and contain an eccentrically located nucleus and large clumps of Nissl-stained material. In the electron microscope the most notable feature of these neurons is the presence of ribosome rosettes and many parallel arrays of rough endoplasmic reticulum (RER). On the basis of cytological and ultrastructural features, we conclude that only one class of large neuron is present. Although in the light microscope the small neurons appear to be similar, at the ultrastructural level three neuron types have been distinguished: (1) ovoid shape with cytoplasm densely packed with organelles especially RER, (2) round shape with very little cytoplasm with few organelles, and (3) triangular shape with a pale cytoplasmic matrix with some RER. Subsurface membrane configurations are often seen in the somata of all neuron types. In addition, axon terminals, some containing flat vesicles, and other less frequent ones containing round vesicles are seen terminating on the somata of all neuronal cell types. In the neuropil, three types of presynaptic profiles can be identified. Two of these profiles are axodendritic and the third is dendrodendritic. The type R profile, which is often as large as 4 micron 2, is the most numerous, contains large round synaptic vesicles, and is often seen synapsing on several dendritic profiles. The type F profile contains flat vesicles and a relatively dense cytoplasm, and is smaller in area than type R. The third profile, which contains small clusters of pleiomorphic vesicles and apparently is dendritic, forms synapses with dendritic profiles. We propose that the type R axon terminals originate mostly from the retina and the type F mostly from the visual telencephalon.
Intraspinal synovial cysts: A retrospective study

Background: We report the clinical presentation, radiographic studies, intraoperative findings, histopathological analysis, and post-treatment outcome in 26 patients diagnosed with spinal synovial cysts (SSCs). Aims: To describe the clinical presentation, radiographic studies, operative findings, and postoperative follow-up in 26 patients with SSCs. Settings and Design: The study was retrospective in design, involving chart review. Individual patient data was tabulated and patterns were recognized. Materials and Methods: The charts for 26 patients who underwent surgical extirpation of SSC between April 1993 and October 2002 were retrospectively reviewed. Specifically, initial clinical presentation, pertinent radiographs (X-rays, magnetic resonance imaging, computed tomography), intraoperative findings, histopathology, and postoperative follow-up were noted. Statistical Analysis Used: Patient data was tabulated and analyzed for patterns in demographics, symptoms and histopathology. Results: SSCs were more common in females than males (17:9 ratio). Presenting symptoms were back pain with radiculopathy in 13 (50%), radicular pain in the absence of back pain in 10 (38%), and back pain without radicular pain in three (11%). In addition, 17 patients (65%) had sensory deficit, and 9 (35%) had motor deficit. Most SSCs occurred at the lumbar (19/26) or lumbosacral (5/26) regions, with only 2 (2/26) in the thoracic region. One patient had bilateral SSC at the L4-5 level. Intraoperatively, each cyst was located adjacent to a degenerated facet joint. These lesions could grossly be identified intraoperatively and histopathological confirmation was achieved in all the cases. Conclusions: SSCs are important lesions to consider in the differential diagnosis of lumbar epidural masses and surgical resection leads to significant improvement in the majority of cases.
Self-report of quality of medical student health care.

Objectives To summarise survey results for the quality of medical students' personal health care, characterise the results according to the demographics and career orientations of the students, and evaluate the relationship between the perceived quality of health care received and the degree of emphasis on prevention in the health care provided. Methods We carried out a cross-sectional study with 2316 medical students in the class of 2003 from 16 medical schools, surveyed at 3 points during their training. We used a self-administered questionnaire designed to assess personal health care and related variables in medical students. Results The majority (92%) reported receiving health care that was at least good, but only a minority (23%) said they received excellent health care. Half had a regular doctor. Health care quality was rated more highly at Year 1 orientation than at later timepoints by students who had a regular personal doctor, and especially by those with personal doctors who emphasised prevention. Conclusions The majority of medical students perceived that they had received health care that was good or better, but most did not believe it was excellent. As the provision of preventive care is important to students, increasing the amount of preventive care provided to students may both increase their personal satisfaction with their health care and model good clinical preventive practices for them.
CO Tolerance of Carbon-Supported Platinum-Ruthenium Catalyst at Elevated Temperature and Atmospheric Pressure in a PEM Fuel Cell

Experiments were performed to determine the carbon monoxide (CO) tolerance of an atmospheric pressure, hydrogen-oxygen, proton-exchange-membrane (PEM) fuel cell at elevated temperatures (80 to 120°C). A Nafion-Teflon-Zr(HPO 4 ) 2 composite membrane was used to avoid the high resistance normally encountered with a Nafion membrane due to dehydration at the low reactant relative humidities encountered under these conditions. A Pt-Ru/C (40 wt % precious metal, Pt/Ru = 1/1 atomic ratio) anode catalyst of 0.4 mg Pt-Ru/cm 2 loading was used. The anode polarization decreased significantly as the cell temperature was increased from 80 to 105 to 120°C due to both smaller CO coverage on the anode catalyst and improved activity of the catalyst for CO and hydrogen oxidation. At elevated temperatures, the loss of water at the anode resulted in an increase in the measured cell resistance with increasing CO concentration. This effect is presumed to be due to an increase in the anode polarization that was partially measured along with the membrane resistance, when determined using the current interruption technique. The cell performance did not increase monotonically with temperature. When the CO concentration in the hydrogen at the anode was above 100 ppm, the fuel cell performance at 105°C was higher than that at 80°C. Dehydration of the membrane and catalyst layers tended to offset improved CO tolerance at elevated temperatures from 105 to 120°C at the same reactant water vapor content.
Controlling Indium Incorporation in InGaN Barriers with Dilute Hydrogen Flows.

Abstract InxGa1−xN multiple quantum wells (MQWs) with InyGa1−yN barriers were grown by adding dilute hydrogen flows to the QW growth conditions in order to modify the barrier indium composition. With the H2 flow off, the indium concentration in the InxGa1−xN QWs were x=0.183, x=0.163, and x=0.096 for growth temperatures of 730, 750 and 770 °C respective. Using these same QW growth conditions, the H2 flow was increased up to 3 SLM resulting in a gradual decrease in the indium concentration in the InyGa1−yN barriers. Kinetic analysis suggests that hydrogen enhances indium surface desorption through the formation of more volatile indium-hydride species, thereby decreasing the surface indium concentration available for incorporation into the InyGa1−yN barriers. For the MQW structures grown at 750 °C, the photoluminescence (PL) wavelength blue-shifts from 477 to ~450 nm as the indium in the InyGa1−yN barriers increases as expected from the reduced influence of the piezoelectric fields. While a corresponding increase of spontaneous emission from the increasing overlap of electron states within the QW is also expected, the PL intensity of the QW instead decreases. This conflicting expectation of increased spontaneous emission and the observation of decreased PL intensity suggest either decreases in the QW-barrier height or increases in non-radiative defects offset any efficiency gains obtained when InGaN barriers to reduce polarization fields within the QWs.
NATURE OF THE PLANT COMMUNITY. III. FLOWERING BEHAVIOR WITHIN TWO GRASSLAND COMMUNITIES UNDER RECIPROCAL TRANSPLANTING

THE GRASSLAND type of community is an ideal experimental unit. Its structure allows a multiplicity of approaches toward a fuller understanding of the nature of the plant community. In two previous studies (McMillan, 1956a, b) of this fundamental ecological unit, transplanting of members to a uniform garden proved helpful in understanding behavior within grassland communities. In the present evaluation, the separation of habitat effects from genetic controls within the community is approached by the reciprocal transplanting of members of a prairie community and a sandhill community. Such a separation of habitat and genetic controls proved to be valuable in interpreting community phenomena in non-experimental habitats. A plant community as used in this discussion is a piece of vegetation around which a boundary can be drawn. The boundary imposed on the experimental community would include the members of each experimental population investigated. The community site from which the experimental populations are removed obviously can be carved up into numerous small communities or be treated as one large community. Here it is treated as one community. The earlier studies by Steiger (1930) at the prairie collection site separated the vegetation into smaller units which were placed in a number of categories or types of communities. Recent studies of communities in sandhill areas of Nebraska include those of Frolik and Shepherd (1940) and Tolstead (1942). METHODS AND MATERIALS.-A community from the loess hills, 9 miles west of Lincoln, Nebraska, was selected for comparison with one in the sandhills ca. 225 miles west of Lincoln. The sandhill location was in an ungrazed, unmowed area within the Nebraska National Forest at Halsey. The Lincoln area, the site of Steiger's investigation (1930) of the structure of prairie vegetation, has received annual mowings. The two community sites have obvious soil and climatic differences. However, they contain a surprisingly similar list of species. In both areas occur Andropogon scoparius Michx., Sorghastrum nutans (L.) Nash., Koeleria cristata (L.) Pers., Stipa spartea Trin., Bouteloua gracilis (H.B.K.) Lag., B.hirsuta Lag., Panicum virgatun L., Elymus canadensis L., Andropogon gerardi Vitman, Helianthus rigidus (Cass.) Des'f., Artemisia gnaphalodes Nutt., and Rosa arkansana Porter. Such grasses as
Modelling cost-effectiveness of different vasectomy methods in India, Kenya, and Mexico.

Vasectomy is generally considered a safe and effective method of permanent contraception. The historical effectiveness of vasectomy has been questioned by recent research results indicating that the most commonly used method of vasectomy – simple ligation and excision (L and E) – appears to have a relatively high failure rate, with reported pregnancy rates as high as 4%. Updated methods such as fascial interposition (FI) and thermal cautery can lower the rate of failure but may require additional financial investments and may not be appropriate for low-resource clinics. In order to better compare the cost-effectiveness of these different vasectomy methods, we modelled the costs of different vasectomy methods using cost data collected in India, Kenya, and Mexico and effectiveness data from the latest published research. The costs associated with providing vasectomies were determined in each country through interviews with clinic staff. Costs collected were economic, direct, programme costs of fixed vasectomy services but did not include large capital expenses or general recurrent costs for the health care facility. Estimates of the time required to provide service were gained through interviews and training costs were based on the total costs of vasectomy training programmes in each country. Effectiveness data were obtained from recent published studies and comparative cost-effectiveness was determined using cost per couple years of protection (CYP). In each country, the labour to provide the vasectomy and follow-up services accounts for the greatest portion of the overall cost. Because each country almost exclusively used one vasectomy method at all of the clinics included in the study, we modelled costs based on the additional material, labour, and training costs required in each country. Using a model of a robust vasectomy program, more effective methods such as FI and thermal cautery reduce the cost per CYP of a vasectomy by $0.08 – $0.55. Based on the results presented, more effective methods of vasectomy – including FI, thermal cautery, and thermal cautery combined with FI – are more cost-effective than L and E alone. Analysis shows that for a programme in which a minimum of 20 clients undergo vasectomies per month, the cost per CYP is reduced in all three countries by updated vasectomy methods.
Effects of neonatal gonadectomy on DRL behavior

Gonadectomy on the 1st day of life had no effect on the acquisition of DRL behavior by male rats. Together with other findings, the current results suggest that endogenous androgens are relatively unimportant in the development of sex differences in DRL performance during postnatal life.
MESSENGER Mission Overview

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, launched on August 3, 2004, is nearing the halfway point on its voyage to become the first probe to orbit the planet Mercury. The mission, spacecraft, and payload are designed to answer six fundamental questions regarding the innermost planet: (1) What planetary formational processes led to Mercury’s high ratio of metal to silicate? (2) What is the geological history of Mercury? (3) What are the nature and origin of Mercury’s magnetic field? (4) What are the structure and state of Mercury’s core? (5) What are the radar-reflective materials at Mercury’s poles? (6) What are the important volatile species and their sources and sinks near Mercury? The mission has focused to date on commissioning the spacecraft and science payload as well as planning for flyby and orbital operations. The second Venus flyby (June 2007) will complete final rehearsals for the Mercury flyby operations in January and October 2008 and September 2009. Those flybys will provide opportunities to image the hemisphere of the planet not seen by Mariner 10, obtain high-resolution spectral observations with which to map surface mineralogy and assay the exosphere, and carry out an exploration of the magnetic field and energetic particle distribution in the near-Mercury environment. The orbital phase, beginning on March 18, 2011, is a one-year-long, near-polar-orbital observational campaign that will address all mission goals. The orbital phase will complete global imaging, yield detailed surface compositional and topographic data over the northern hemisphere, determine the geometry of Mercury’s internal magnetic field and magnetosphere, ascertain the radius and physical state of Mercury’s outer core, assess the nature of Mercury’s polar deposits, and inventory exospheric neutrals and magnetospheric charged particle species over a range of dynamic conditions. Answering the questions that have guided the MESSENGER mission will expand our understanding of the formation and evolution of the terrestrial planets as a family.
ON THE MAINTENANCE OF ZONAL CIRCULATION IN THE ATMOSPHERE

Abstract The maintenance of a jet-type zonal circulation is discussed from the viewpoint of vorticity balance. Through skin friction, the atmosphere gains vorticity from the earth in the region of anticyclonic vorticity at the surface, and returns it to the earth in the region of cyclonic vorticity at the surface. There are two processes to carry out the vorticity transfer from low to high latitudes: meridional circulation and large, horizontal vortical systems. The efficiency of the two in compensating the frictional effect is about the same in low latitudes. In middle latitudes, the large, horizontal vortical systems are far more efficient. In high latitudes, the role of the mean circulation in maintaining the zonal circulation is negligible.
Resin Infusion Between Double Flexible Tooling: Evaluation of Process Parameters

Manufacturers of lean weight vehicular structures are discovering the advantages of utilizing the high strength to weight ratios found in composite materials. However, traditional closed mold techniques require a long cycle time and relatively expensive tooling. This paper reports on a new technique called Resin Infusion between Double Flexible Tooling (RIDFT). In this innovative process, the resin infusion and resin-fiber wetting are finished between two flexible tools in a two dimensional flat shape and then the entire wetted reinforcement and flexible tooling is formed into a specified part shape by using a vacuum. This process avoids complex resin flow and mold filling issues and saves mold preparation and fiber stacking time. Using a RIDFT prototype, several components were produced. A larger industrial RIDFT machine was constructed to establish its viability for large component manufacture. An evaluation of production parameters, including infusion pressure, resin temperature, number of fiber layers...