cssi/SciSciGPT-SciSciNet huggingface dataset:
INDUCED CELL PROLIFERATION: THE EFFECT OF ISOPROTERENOL.

Abstract Isoproterenol (IPR) in pharmacologic doses produces enlargement of the salivary glands in rat and mouse. Alterations in weight, DNA-content and incorporation of 3H-thymidine in the submaxillary gland of rat were studied using autoradiographic and chemical techniques during a four-week course of IPR treatment. Within 2 days 80 to 100 mg of IPR markedly stimulated the incorporation of 3H-thymidine into the nuclei of acinar cells of the submaxillary gland and into the nuclei of hepatocytes. Continuous administration of the drug produced lesser peaks of labeling by the 7th and 21st day. The percentage of labeled interstitial and duct cells was the highest after treatment for seven days. The weight of the submaxillary gland significantly increased after the administration of IPR for 4 days and reached its maximum 3.5 times normal, after 2 weeks. The amount of DNA per gland was also significantly higher after 4 days of IPR treatment increasing further up to 14 days. The incorporation of 3H-thymidine into DNA per gland was severalfold above control level from the second day on with a 1255 per cent peak after injections of IPR for 4 days. The specific activity of DNA rose to 8 times the control after only 2 days of IPR treatment. These alterations quickly regressed after withdrawal of the drug. Studies on the turnover rate of DNA indicated reutilization of DNA or its catabolites by the cells of submaxillary gland during IPR treatment. Dichloroisoproterenol caused no alteration of the weight, DNA-content and incorporation of thymidine in the submaxillary gland and it partly prevented the effect of IPR.
The Influence of Communication Apprehension on Superiors' Propensity for and Practice of Participative Decision Making

This investigation examined if traitlike communication apprehension (CA) serves as a significant predictor of superiors' propensity for and practice of participative decision making (PDM)—that is, involving others in decision-making processes. A total of 219 superiors recruited from a variety of organizations served as participants in this study. Results revealed that traitlike CA is a significant determinant of variation in superiors' inclination for, as well as their actual practice of, PDM. These findings suggest that superiors with lower CA possess favorable perceptions of PDM and are more inclined to involve others in decision-making processes than their colleagues with higher CA. Conversely, results suggest that superiors with higher CA typically possess less favorable perceptions of PDM and are less likely to involve others when making decisions. Theoretical and practical implications underpinning these results are explored. Future research directions are also proposed.
Problem-Based Learning in Structural Engineering Education

Structural engineering education has been based historically on specialization within the framework of a four-year undergraduate degree in civil engineering. Many practitioners, however, are concerned that modern civil engineering curricula are not meeting the needs of the structural engineering profession. The purpose of this paper is to contribute to the conversation about undergraduate education and the increased technical skills requested by the structural engineering profession. Problem-based learning is presented as a strategy for expanding the civil engineering curriculum to include concentrated study and a problem-solving experience, as well as engaging students in the process of learning how to learn. The paper reports on our experience in incorporating problem-based learning within a senior-year project. The conclusions discuss the challenges of extending this learning format to additional students.
The influence of prestrain on ductility in the superplastic Pb-Sn eutectic alloy

Experiments were conducted to investigate the effect of prestraining on the ductility of the superplastic Pb-62 wt % Sn eutectic alloy at room temperature. It is shown that prestraining at a fast strain rate in region III leads to a decrease in the elongation to failure on subsequent testing at a slower rate in region II. This decrease is due to the development of strain inhomogeneities during the prestrain. There is a further decrease in elongation if a holding time is inserted between the prestrain in region III and the subsequent testing in region II. It is shown also that prestraining at a slow strain rate leads to a sharp increase in the elongation to failure on subsequent testing at a fast strain rate. The reasons for these trends are discussed with reference to the occurrence of grain growth and the uniformity of strain.
Laboratory Investigation of Buoyancy-Induced Flow (Plume Sinking) During Two-Well Tracer Tests

The occurrence of buoyancy-induced vertical flow (sinking) of a bromide (Br{sup {minus}}) tracer plume at small injection concentrations is investigated in transport experiments conducted in a large-scale physical aquifer model containing a homogeneous and isotropic sand pack. Two-well tracer tests are conducted using Br{sup {minus}} at concentrations ranging from 50 to 1,000 mg/l, corresponding to relative densities between 7.5 {times} 10{sup {minus}5} and 1.5 {times} 10{sup {minus}3}. Analysis of three-dimensional solute concentration data indicates that the center of mass of the Br{sup {minus}} plume was displaced downward as the denser tracer solution sank through the sand pack. Plume sinking occurred at all solute concentrations investigated; the magnitude of the vertical displacement increased with increasing Br{sup {minus}} concentration of the injected tracer solution. The dynamic collapse of the Br{sup {minus}} plume caused by buoyancy forces resulted in increased apparent transverse and longitudinal dispersivities. The results suggest that the possibility of buoyancy-induced flow must be considered when interpreting tracer tests conducted with anion concentrations as low as 50 mg/l. The occurrence of buoyancy-induced flows at such low relative densities also suggest that the phenomenon may be more widespread than is generally recognized.
Neuronal vulnerability in mouse models of Huntington's disease: membrane channel protein changes.

Huntington's disease (HD) is caused by a polyglutamine expansion that results in atrophy of the striatum and frontal cortex during disease progression. HD-susceptible striatal neurons are affected chronologically with initial degeneration of the striatopallidal neurons then the striatonigral projections, whereas large aspiny striatal interneurons (LAN) survive. Two classes of critical membrane proteins were evaluated in transgenic mouse models to determine their association with HD susceptibility, which leads to dysfunction and death in selected striatal neuron populations. We examined potassium (K+) channel protein subunits that form membrane ionophores conducting inwardly and outwardly rectifying K+ currents. K+ channel protein staining was diminished substantially in the HD striatal projection neurons but was not expressed in the HD-resistant LAN. Because loss of K+ channel subunits depolarizes neurons, other voltage-gated ionophores will be affected. N-methyl-D-aspartate (NMDA) receptors and their phosphorylation by cyclic AMP were studied as a mechanism contributing to excitotoxic vulnerability in striatal projection neurons that would lose voltage regulation after diminished K+ channels. NR1 subunits showed significant elevation in the HD transgenic projection systems but were expressed at very low levels in LAN. NR1 subunit phosphorylation by cyclic AMP also was enhanced in striatal projection neurons but not in LAN. Cyclic AMP-driven phosphorylation of NMDA receptors increases the channel open time and elevates neuronal glutamate responsiveness, which may lead to excitotoxicity. Together our data suggest that changes in these proteins and their modification may predispose striatal projection neurons to dysfunction and then degeneratation in HD and provide a mechanism for LAN resistance in the disease. © 2005 Wiley-Liss, Inc.
Identification and Resection of Sessile Serrated Adenomas/Polyps during Routine Colonoscopy

Abstract Sessile serrated colon polyps (SSA/Ps) are precursors to colorectal cancer. In comparison to adenomatous polyps, SSA/P can be challenging to detect during colonoscopy; they are often minimally elevated, pale, and concealed behind mucus, a colonic fold, or intraluminal debris. Because they are typically flat, located in the right side of the colon, the same color as the background mucosa, and have indistinct borders, SSA/P resection also poses challenges. The authors present examples of typical SSA/Ps that illustrate pitfalls and pearls in SSA/P detection and resection. This article is part of an expert video encyclopedia.
Intervention Effectiveness for Children and Youth

We reviewed 11 articles, including efficacy and effectiveness studies, addressing intervention effectiveness for children and youth published in 2012 in the American Journal of Occupational Therapy and organized them by level and type of research according to a framework adapted from the International Classification of Functioning, Disability and Health. Compared with articles published in previous years, these studies showed improvement in their ability to guide practitioners to make evidence-based decisions by increasing understanding of the intervention's pragmatic relevance and the extent to which it promotes participation in childhood and adolescent occupations. Studies' evidence levels have increased along with efforts to increase scientific rigor. Intervention fidelity was included in several of the studies, but not consistently. Siblings and other family members were not examined, and none of the articles reviewed described longitudinal studies. Measures of client acceptability and cost-benefit analysis need more attention in future studies.
Effect of irradiation on preliminarily radiation-oxidation-treated stainless steel

Radiolytic processes of decomposition of water on specimens of stainless steel subjected to preliminary radiation-oxidation treatment are studied.
Optimal power-limited rendezvous of a spacecraft with bounded thrust and general linear equations of motion

The solution of the fixed-time optimal power-limited rendezvous with a general linear system of ordinary differential equations and a bound on the magnitude of the applied thrust is presented. Necessary and sufficient conditions for thrust saturation in an optimal solution are included. Because of the generality of the linear system of equations of motion, controllability considerations are required for a complete solution of this problem. It is shown that the condition of controllability can be defined completely in terms of a class of primer vectors associated with this problem. Moreover, it is shown that two distinct versions of the primer vector appear in this problem. Therefore, there is not a unique primer vector associated with every rendezvous problem. The work is applied to the problem of the rendezvous of a spacecraft near a satellite in circular orbit. The optimal rendezvous trajectory is determined by the interaction of a primer vector and the bound on the thrust magnitude. The results of computer simulations are presented graphically.
North American Origins of Middlewestern Frontier Populations

Interpretations of American regional cultural geography have been based on inferred migration patterns of people who produced the first effective settlement of various regions. Empirically derived estimates of population origins can be constructed by combining locationally precise birthplace data from county histories with census data on state of birth. Such estimates for counties of the middlewestern states reveal the extent of latitudinal zonation in the westward migration process. Yankee and Midland culture hearths dominate most of the Middle West except for the upper Great Lakes and the southern fringe. A zone of Yankee-Midland mixture widens from a narrow strip east of Lake Michigan to a broad, discontinuous region stretching from Kansas to South Dakota. The problem of finding a northern limit for the Upland South in the Middle West is compounded by the inclusion of some Lowland South influence and by the mingling of migration streams that took place in Ohio and Indiana. Sharp boundaries (“cultural divides”) are largely absent except along the western and northern edges of Missouri and along the southern edges of lakes Erie and Michigan. The latitudinal zonation of migrant origins over most of the Middle West is too strong to fit a model of migration based on the assumption of directionally biased dispersion from separate sources.
Carrier accumulation and space-charge-limited current flow in field-effect transistors

Field effect transistors with nonuniform doping profiles along channel, calculating carrier accumulation and space charge limited current flow by two dimensional model analysis
Perspectives on ethnicity, gender and race and their empirical referents: a four-sided paradigm and critical review

Based on a sample of general textbooks in sociology, this article proposes a heuristic, four-sided paradigm of the extant literature on ethnicity, gender and race and highlights their empirical referents: (1) order–integrative, which emphasizes the progressive adaptation of ethnic and racial groups to a dominant, Anglo-Saxonic, Eurocentric culture; (2) pluralist–multiculturalist, which emphasizes markers of social differentiation between ethnic and racial groups that are compatible with social diversity; (3) power–conflict–stratification, which frames successive generations of minority ethnics in contentious power relations amongst themselves relative to the perceived or actual mainstream white powerbrokers in society; and (4) gender–feminist, which critically analyses the white, male, heterosexual bias and hegemony built into the structures and practices of social institutions and social discourse. The paper concludes by suggesting further research on cross-national perspectives as developed countries be...
Optical Feedback And Bistability: A Review

This paper presents a review of the various applications of feedback in optical systems. There are two general areas, optical image processing and bistability. In optical image processing both coherent (optical spatial feedback network internal to an optical resonator) and hybrid (TV) systems are discussed. In the area of bistability there are molecular systems (atoms in an optical resonator), both absorptive and dispersive; hybrid (employing electronic feedback) single-beam and many-element (TV and spatial light modulator-based) systems. All the systems are discussed. A detailed model showing the many facets of molecular bistability is presented along with a discussion of catastrophe theory applied to optical bistability.
Design for packageability-early consideration of packaging from a VLSI designer's viewpoint

Designing VLSI dies without considering packaging issues may result in a suboptimum system. It is argued that before the design of VLSI dies is completed, packaging issues should be evaluated, since they may affect choices in VLSI circuit design and layout. To illustrate this, the design of an image processing chip-set of three integrated circuits for wire-bond printed circuit board (PCB) and flip-chip multichip module deposited (MCM-D) technologies is reviewed. It is shown that the characteristics of these chips vary, since they are designed with different packaging in mind. >
Functional MRI of the human brain at 1.5 T during auditory, somatosensory, and visual stimulation

Human studies were conducted to determine the feasibility of functional MRI at 1.5 T during auditory stimulation in the presence of gradient sound generated during a conventional gradient-echo sequence. The gradient-echo pulse sequence was optimized to minimize the effect of gradient sound. Stimuli comprised a simple 1 kHz tone as well as spoken words to investigate possible localization during language comprehension. Also, functional images in response to somatosensory and visual stimulation were generated, albeit with a different gradient-echo sequence to optimize contrast and temporal resolution. The resulting functional images indicate a 2 - 9% increase in signal intensity localized to the corresponding auditory, somatosensory or visual cortical regions during stimulation.
ALGEBRAIC CYCLES AND VECTOR BUNDLES ON REAL AFFINE THREEFOLDS

LetX=Spec(B), whereB is a regular ring of Krull dimension 3 which is a finitely generatedR-algebra. We give necessary and sufficient conditions for the existence of a vector bundle of rank 3 onX with prescribed Chern classes. 1 Research supported by NSF Grant DMS-8602672
Sea change for metagenomics

Ed DeLong comments on the impact that the Global Ocean sampling expedition will have on marine and Earth science.
Sociodemographic Risk Factors for Autism in a US Metropolitan Area

The present study examined the association between autism and sociodemographic factors, overall and in subgroups of children with autism with and without mental retardation (Autism/MR and Autism/No MR, respectively); the association was further examined in subanalyses by child’s source of ascertainment to assess the presence of ascertainment bias. In the main analyses, one marker of higher social class (higher median family income) was significantly associated with autism overall. Both markers of higher social class (higher maternal education and higher median family income) were significantly associated with autism/no MR, but not associated with autism/MR. In the subanalyses, associations with social class varied by ascertainment source. Future studies should consider phenotypic subgroups of children with autism and must consider potential ascertainment bias.
Modeling inhomogeneous van der Waals fluids using an analytical direct correlation function.

Rosenfeld's perturbative method [J. Chem. Phys. 98, 8126 (1993)] for constructing the Helmholtz energy functional of classical systems is applied to studying inhomogeneous Lennard-Jones fluids, in which the key input---the bulk direct correlation function---is obtained from the first-order mean-spherical approximation (FMSA) [J. Chem. Phys. 118, 4140 (2003)]. Preserving its high fidelity at the bulk limit, the FMSA shows stable and satisfactory performance for a variety of inhomogeneous Lennard-Jones fluids including those near hard walls, inside slit pores, and around colloidal particles. In addition, the inhomogeneous FMSA reproduces reliably the radial distribution function at its bulk limit. The FMSA is found, in particular, much better than the mean-field theory for fluids near hard surfaces. Unlike alternative non-mean-field approaches, the FMSA is computationally as efficient as the mean-field theory, free of any numerical determination of structure information, weight functions, or empirical parameters.
Porcine Cardiac Xenograft Valves: Analysis of Survival, Valve Failure, and Explantation

Porcine cardiac xenografts were used for cardiac valve replacement in 1,093 patients. Hospital mortality for aortic valve replacement (AVR) was 3.7%; for mitral valve replacement (MVR), 7.8%; and for AVR + MVR, 4.7%. Total follow-up was 2,036 patient-years; maximum, 7.3 years; and mean, 1.89 years. Actuarial survival (+/- standard error of the mean) for AVR was 84% +/- 2% at 56 months; for MVR, 84% +/- 3% at 56 months; and for AVR + MVR, 86% +/- 4% at 30 months. Nonfatal thromboembolism occurred in 8 of 1,030 patients (0.78%). Anticoagulation was not routinely employed. Fifty hospital survivors (4.8%) experienced valve dysfunction; 18 of the survivors (1.7%) died; and 32 of the survivors (3.1%) underwent reoperation. The rate of dysfunction increased slowly until the sixth year when an increased rate was observed (p less than 0.0001). Patients less than 34 years old had a higher incidence of dysfunction (p less than 0.01). Thirty-two hospital survivors (3.1%) underwent explantation of the porcine valve for late dysfunction. Valve dysfunction secondary to endocarditis and paravalvular leak occurred early, while leaflet deterioration or thrombosis was more gradual in onset and was noted later. The porcine valve has functioned well for 1 to 7 years with a low incidence of valve related morbidity and mortality without routine anticoagulation in patients older than 34 years of age.
Acquired haemostatic defects in the ill newborn.

Summary. The kinetics and function of platelets and fibrinogen were studied in 22 ill newborns. Overall 51Cr-platelet survival was considerably shortened (patients 2·6 d ± 1·7, adult normal 9·5 d ± 0·6, P < 0·001) while 125I-fibrinogen surival was less severely decreased (patients 2·1 d ± 0·8, adult normal 5·1 d ± 0·4, P < 0·05). Three patients with bacterial sepsis and one with disseminated herpes simplex had the most severely reduced platelet survival times (1·3 d ± 0·9), causing thrombocytopenia (62 ±32 × 109/l) despite production rates averaging 2 1/2 times normal. Although fibrinogen survival times were comparably reduced in these patients to 1·4 d ± 0·4, fibrinogen concentrations were normal because of compensatory increased production. In three patients with necrotizing enterocolitis platelet and fibrinogen survival times were similarly reduced (platelets 1·6 d ± 0·6, fibrinogen 1·6 d ± 0·6) with platelet counts of 69 ± 27 × 109/l and platelet production rates of twice normal. Since their fibrinogen production was not increased, they had decreased fibrinogen concentration (1·0 ± 0·19 g/l). In six patients with respiratory distress syndrome the kinetic results were more variable. Platelet survival was less severely affected than in the other groups and production was approximately twice normal; hence, the platelet count was maintained (177 ± 107 × 109/l). Fibrinogen in this group was slightly reduced because of decreased production in the presence of mildly decreased survival (2·7 d ± 0·7). The two patients with cytomegalovirus infection had severe thrombocytopenia (23 × 109/l) due to a combination of decreased platelet survival (3·6 d), increased splenic pooling and no compensatory increase in marrow platelet production. Fibrinogen production was normal but its plasma concentration was moderately reduced because of a decrease in fibrinogen survival. In many of these patients, fibrinogen dysfunction was suggested by a prolonged thrombin time and a discrepancy between fibrinogen concentration as determined by a time dependent assay and an equilibrium total clottable protein assay. Likewise, platelet dysfunction, evidenced as a prolonged bleeding time, was found in patients with RDS; some of these infants had otherwise unexplained bleeding.
A very high energy-efficiency switching technique for SAR ADCs

A high energy-efficiency capacitor switching scheme for a successive approximation register (SAR) analog-to-digital converter (ADC) is presented in this paper. The proposed switching technique achieves a zero energy dissipation in the first 2 comparison cycles and a 4X reduction in total capacitance used in the digital-to-analog converter (DAC), i.e., for the same total capacitance, the proposed technique can produce 2 additional bits of resolution than a conventional SAR. The proposed method can achieve 95% savings in switching energy over a conventional SAR. The result has been verified through behavioral simulations.
A proof of quasi-independence of sliding window flow control and go-back- n error recovery under independent packet errors

A quasi-independence result holds for the go-back-n automatic repeat request (ARQ) protocol and the sliding window flow control protocol if packet errors are independent. The result is independent of the magnitude of the packet error probability or the cost of an error. A parallel result for the selective repeat ARQ protocol, however, does not appear to hold.
Polar temperature sensitivity to lunar forcing

Climate models and paleoclimatic evidence suggest that the earth's polar regions are particularly responsive to global scale climatic forcing. Empirical climatological evidence of the last century has thus far failed to confirm conclusively this regional sensitivity. We conduct an empirical study of polar sensitivity to climate forcing by comparing a high-quality, 17-year satellite-derived dataset of daily temperatures for 2.5° latitudinal bands to a known external forcing mechanism, the lunar phase cycle. The earth's polar regions display a temperature range of greater than 0.55°C over the course of a synodic (29.53 day) month. This lunar-influenced range in temperature is 25 times larger than a similarly computed range in aggregated global temperatures over a synodic month. Temperature variations between the polar and non-polar regions also produce a pronounced temporal shift in sensible heat transfer. Strong poleward transfer of heat dominates near the full moon but the transfer substantially weakens near the new moon. It is unlikely that this sensitivity can be explained by the type of polar forcing previously identified in GCM simulations and paleoclimatic reconstructions, because of the short duration of the lunar cycle. However, it does demonstrate a new and potentially important external influence on the polar regions' climates.
Arms Versus Alliances The Capital Structure of Military Enterprise

If a state can choose between arming itself (by extracting resources from its domestic constituents) or seeking allies who will pledge military resources to that state, does there exist an optimal ratio of its own arms to its allies' arms? This question is pursued by analogy with a corporation's ratio of debt to equity in its capital structure. Classical finance theory suggests two propositions which, if applicable to alliances, imply that there is no optimal ratio, but allies will expect greater returns from the alliance if the ratio rises. Recent theories in finance imply that the arms to allies ratio does matter and should decrease in response to increases in either the domestic costs associated with arming or the riskiness of the state's military situation. These propositions are tested using Correlates of War (COW) data. The results do not support the classical arguments as to the irrelevance of the arms to allies ratio and suggest that this measure of military capital structure responds to risk.
Terephthalamide derivatives as mimetics of the helical region of Bak peptide target Bcl-xL protein.

Abstract A group of novel Bcl-xL/Bak antagonists, based on a terephthalamide scaffold, were designed to mimic the α-helical region of the Bak peptide. Good in vitro inhibition potencies in disrupting the Bak/Bcl-xL complex have been observed (terephthalamide 4, Ki=0.78±0.07 μM).
Attack-Resistant Trust Metrics

The Internet is an amazingly powerful tool for connecting people together, unmatched in human history. Yet, with that power comes great potential for spam and abuse. Trust metrics are an attempt to compute the set of which people are trustworthy and which are likely attackers. This chapter presents two specific trust metrics developed and deployed on the Advogato Website, which is a community blog for free software developers. This real-world experience demonstrates that the trust metrics fulfilled their goals, but that for good results, it is important to match the assumptions of the abstract trust metric computation to the real-world implementation.
Analyzing and engineering cell signaling modules with synthetic biology

Signaling pathways lie at the heart of cellular responses to environmental cues. The ability to reconstruct specific signaling modules ex vivo allows us to study their inherent properties in an isolated environment, which in turn enables us to elucidate fundamental design principles for such motifs. This synthetic biology approach for analyzing natural, well-defined signaling modules will help to bridge the gap between studies on isolated biochemical reactions-which can provide great mechanistic detail but do not capture the complexity of endogenous signaling pathways-and those on entire networks of protein interactions-which offer a systems-level view of signal transduction but obscure the mechanisms that underlie signal transmission and processing. Additionally, minimal signaling modules can be tractably engineered to predictably alter cellular responses, opening up possibilities for creating biotechnologically and biomedically useful cellular devices.
Portfolio Management and Profitability in Early-Nineteenth-Century Banking

Notwithstanding the importance of maintaining soundness, commercial banks in early ante-bellum America still strove to maximize profits, according to Professor Adams, who cites Stephen Girard's conservative private bank as an example. Using internal data from Girard's bank, of the kind that is seldom available for banks, he shows that a flexible policy of shifting from government and quasi-government securities, as they became scarcer, to business debt, both long- and short-term, kept bank profits from declining. So long as Girard lived, his bank remained fully competitive with the growing number of chartered institutions.
Gender Differences in the Effect of Linguistic Acculturation on Substance Use Among Mexican-Origin Youth in the Southwest United States

This study tested for gender differences in the impact of linguistic acculturation on pro-drug norms, substance use intentions, and actual substance use among youth of Mexican heritage in a large metropolitan area in the Southwest United States. The authors analyzed baseline survey data provided by 2,487 middle school students of Mexican heritage who were part of a larger, multiethnic randomized efficacy trial of a drug abuse prevention program. Using multi-group structural equation modeling, the authors found that linguistic acculturation was positively and directly related to adherence to pro-drug norms, substance use intentions, and recent alcohol use, controlling for age, poor grades, and socioeconomic status. In addition, linguistic acculturation had an indirect effect on substance use intentions and recent alcohol use through pro-drug norms. The direct effect of linguistic acculturation on pro-drug norms was stronger for girls than for boys, as was its indirect effect on substance use intentions.
Simplification of vector fields over tetrahedral meshes

Vector fields produced by experiments or simulations are usually extremely dense, which makes their manipulation and visualization cumbersome. Often, such fields can be simplified without much loss of information. A simplification method for 3D vector fields defined over tetrahedral meshes is presented. The underlying tetrahedral mesh is progressively simplified by successive half-edge collapses. The order of collapses is determined by a compound metric which takes into account the field and domain error incurred as well as the quality of the resulting mesh. Special attention is given to the preservation of the mesh boundary and of critical points on the vector field. A tool has been developed for the measurement of the difference between two vector fields over tetrahedral meshes, and it is used to quantify the simplification error
Finessing the fracture energy barrier in ballistic seed dispersal.

Fracture is a highly dissipative process in which much of the stored elastic energy is consumed in the creation of new surfaces. Surprisingly, many plants use fracture to launch their seeds despite its seemingly prohibitive energy cost. Here we use Impatiens glandulifera as model case to study the impact of fracture on a plant’s throwing capacity. I. glandulifera launches its seeds with speeds up to 4 m/s using cracks to trigger an explosive release of stored elastic energy. We find that the seed pod is optimally designed to minimize the cost of fracture. These characteristics may account for its success at invading Europe and North America.
Induced cell clustering enhances islet /spl beta/ cell formation from pancreatic ductal epithelial cells

Although islet transplantation holds great promise as a treatment for diabetes, a major limitation to its future clinical use is a shortage of donor tissue. During both fetal development and adult pancreatic regeneration, pancreatic ductal epithelial cells (PDEC) differentiate into endocrine cells. The goal of this project is to apply existing understanding of these processes to stimulate islet cell differentiation in vitro. Following 11-14 days of culturing adult human PDEC in a standard cell culture environment (tissue culture treated plastic, 10% FBS), they transdifferentiate to /spl beta/ cells at an extremely low efficiency (0.1%). /spl beta/-cell differentiation was enhanced greater than 4-fold (0.42%) when PDEC were grown on a low adhesive substrate (nontreated plastic) and in a low serum medium (5% Nu serum), conditions which are permissive to cell detachment and clustering. While the overall efficiency of transdifferentiation was still very low, the results suggest that induced cell-cell interactions and cell shape changes may be critical to stimulating /spl beta/-cell production in vitro. We are currently exploring additional factors (ECM factors, growth factors, transcription factors) that may improve the efficiency of transdifferentiation in order to optimize the creation of tissue-engineered islets.
Singlet gradient index lens for deep in vivo multiphoton microscopy

Micro-optical probes, including gradient index (GRIN) lenses and microprisms, have expanded the range of in vivo multiphoton microscopy to reach previously inaccessible deep brain structures such as deep cortical layers and the underlying hippocampus in mice. Yet imaging with GRIN lenses has been fundamentally limited by large amounts of spherical aberration and the need to construct compound lenses that limit the field-of-view. Here, we demonstrate the use of 0.5-mm-diameter, 1.7-mm-long GRIN lens singlets with 0.6 numerical aperture in conjunction with a cover glass and a conventional microscope objective correction collar to balance spherical aberrations. The resulting system achieves a lateral resolution of 618 nm and an axial resolution of 5.5 μm, compared to lateral and axial resolutions of ∼1 μm and ∼15 μm, respectively, for compound GRIN lenses of similar diameter. Furthermore, the GRIN lens singlets display fields-of-view in excess of 150 μm, compared with a few tens of microns for compound GRIN lenses. The GRIN lens/cover glass combination presented here is easy to assemble and inexpensive enough for use as a disposable device, enabling ready adoption by the neu-
What is the Real Thing in the Museum? An Interpretative Phenomenological Study

This article describes a study of the different ways museum visitors understand their experience of the real thing (TRT) in the museum context. Many professionals and scholars claim that the uniqueness of the museum – in relation to other leisure and educational experiences and offerings – centers on being the keepers of ‘real things.’ Having an insight into the visitor perspectives of what they consider real is important and relevant to museum professionals as well as other cultural heritage workers as it can assist them to better respond to visitor experiences of TRT. The study used an interpretative phenomenological analysis approach to inquire into the qualitatively different ways of understanding the experience of TRT in the museum. The research resulted in four ways of understanding an experience of TRT in museums: through aspects of the self, in relation to others, through the presence of the actual physical thing, and through one's surroundings.
Comparison of David V valve-sparing root replacement and bioprosthetic valve conduit for aortic root aneurysm

Objective Valve sparing root replacement (VSRR) is an attractive option for the management of aortic root aneurysms with a normal native aortic valve. Therefore, we reviewed our experience with a modification of the David V VSRR and compared it with stented pericardial bioprosthetic valve conduit (BVC) root replacement in an age-matched cohort of older patients. Methods A total of 48 VSRRs were performed at our institution, excluding those on bicuspid aortic valves. We compared these cases with 15 aortic root replacements performed using a BVC during the same period. Subgroup analysis was performed comparing 16 VSRR cases and 15 age-matched BVC cases. Results The greatest disparity between the VSRR and BVC groups was age (53 vs 69 years, respectively; P P = .036). None of the VSRR and 3 of the BVC procedures were performed for associated dissection ( P = .101). Postoperative aortic insufficiency grade was significantly different between the 2 groups ( P = .004). The cardiopulmonary bypass, crossclamp, and circulatory arrest times were not different between the VSRR and BVC groups (174 vs 187 minutes, P = .205; 128 vs 133 minutes, P = .376; and 10 vs 13 minutes, respectively; P = .175). No differences were found between the 2 groups with respect to postoperative complications. One postoperative death occurred in the BVC group and none in the VSRR group. The postoperative length of stay and aortic valve gradients were less in the VSRR group (6 vs 8 days, P = .038; 6 vs 11.4 mm Hg, P = .001). The intensive care unit length of stay was significantly less in the VSRR group (54 vs 110 hours, P = .001). Conclusions VSRR is an effective alternative to the BVC for aortic root aneurysm.
Take-off mechanics in hummingbirds (Trochilidae)

Initiating flight is challenging, and considerable effort has focused on understanding the energetics and aerodynamics of take-off for both machines and animals. For animal flight, the available evidence suggests that birds maximize their initial flight velocity using leg thrust rather than wing flapping. The smallest birds, hummingbirds (Order Apodiformes), are unique in their ability to perform sustained hovering but have proportionally small hindlimbs that could hinder generation of high leg thrust. Understanding the take-off flight of hummingbirds can provide novel insight into the take-off mechanics that will be required for micro-air vehicles. During take-off by hummingbirds, we measured hindlimb forces on a perch mounted with strain gauges and filmed wingbeat kinematics with high-speed video. Whereas other birds obtain 80–90% of their initial flight velocity using leg thrust, the leg contribution in hummingbirds was 59% during autonomous take-off. Unlike other species, hummingbirds beat their wings several times as they thrust using their hindlimbs. In a phylogenetic context, our results show that reduced body and hindlimb size in hummingbirds limits their peak acceleration during leg thrust and, ultimately, their take-off velocity. Previously, the influence of motivational state on take-off flight performance has not been investigated for any one organism. We studied the full range of motivational states by testing performance as the birds took off: (1) to initiate flight autonomously, (2) to escape a startling stimulus or (3) to aggressively chase a conspecific away from a feeder. Motivation affected performance. Escape and aggressive take-off featured decreased hindlimb contribution (46% and 47%, respectively) and increased flight velocity. When escaping, hummingbirds foreshortened their body movement prior to onset of leg thrust and began beating their wings earlier and at higher frequency. Thus, hummingbirds are capable of modulating their leg and wingbeat kinetics to increase take-off velocity.
Assessing Grammatical Development in Interactional Contexts.

The TESOL Quarterly invites readers to submit short reports and updates on their work. These summaries may address any areas of interest to Quarterly readers. Authors' addresses are printed with these reports to enable interested readers to contact the authors for more details.
Folklore and Literacy: A View from Nova Scotia

This article describes a pilot project in museum based literacy learning that took place in Windsor, Nova Scotia in the autumn of 1999. The author coordinated the project in close consultation with a local literacy practitioner. The Windsor study was part of a national project undertaken by the Canadian Museums Association and funded by a SSHRC Strategic Research Grant Initiative. The project attracted four female participants, although one left before completing her research for personal reasons. The women chose objects as topics for study, and were given assistance with research and documentation techniques. As a discourse involving traditions of expressive behaviour and worldview, folklore plays an important role in literacy education. Specifically, this discussion examines the interactions between the participants, their chosen topics, and the museum environments, and underscores the need for an understanding of value, class, gender and contexts of use in an appreciation of literacy. A review of relevant literature is included, focusing on ethnographic studies of literacy with particular emphasis on recent work in Atlantic Canada. Outcomes of the study and future directions for this kind of community based, qualitative research are also discussed.
Vertically polarized radar backscattering from the rear of a cone or cylinder

Previous work indicates that although accurate predictions are generally obtained from the geometrical theory of diffraction for cylinders and frustums, scattering from the rear edges of these bodies is sometimes poorly predicted. A new formulation provides satisfactory results for a cylinder, but conical bodies require further work.
An observation of lower rates of drug use over time in community syringe exchangers.

Background and Objectives The present study evaluated changes in rates of self-reported heroin and cocaine use in opioid-dependent individuals newly registered to a syringe exchange program (SEP), and examined the effects of recovery-oriented longitudinal variables (i.e., substance abuse treatment, self-help group participation, employment) on changes in drug use. Methods Study participants (n = 240) were opioid-dependent and drawn from a larger study evaluating strategies to improve treatment-seeking. Mixed model analyses were used to evaluate changes in rates of heroin and cocaine use, and longitudinal correlates of change in these substances, over a one-year period. Results Results showed reductions in days of heroin and cocaine use over time, and that participation in recovery-oriented activities was strongly associated with greater changes in drug use. Conclusions and Scientific Significance These results suggest SEPs can play a vital role in facilitating reductions in drug use through motivating participation in treatment and other recovery-oriented activities. (Am J Addict 2013; 22:271–276)
A word in the hand: action, gesture and mental representation in humans and non-human primates

The movements we make with our hands both reflect our mental processes and help to shape them. Our actions and gestures can affect our mental representations of actions and objects. In this paper, we explore the relationship between action, gesture and thought in both humans and non-human primates and discuss its role in the evolution of language. Human gesture (specifically representational gesture) may provide a unique link between action and mental representation. It is kinaesthetically close to action and is, at the same time, symbolic. Non-human primates use gesture frequently to communicate, and do so flexibly. However, their gestures mainly resemble incomplete actions and lack the representational elements that characterize much of human gesture. Differences in the mirror neuron system provide a potential explanation for non-human primates' lack of representational gestures; the monkey mirror system does not respond to representational gestures, while the human system does. In humans, gesture grounds mental representation in action, but there is no evidence for this link in other primates. We argue that gesture played an important role in the transition to symbolic thought and language in human evolution, following a cognitive leap that allowed gesture to incorporate representational elements.
T'ien-hsia and Kuo, and the "Transvaluation of Values"

CONFUCIAN reformers found a great deal wrong with China in the seventeenth century. The trouble was this, they felt: men had strayed from the fixed ideals of Chinese civilization. In the early twentieth century, antiConfucian reformers found a great deal wrong in the China of their day; they traced disaster, however, not to the flouting of fixed ideals but to blind and slavish respect for them, to the fixity itself. A seventeenth-century world, a t'ien-hsia Ad:, in which traditional values claimed authority, had become a twentieth-century nation, a kuo KI, in which traditional valueswere impugned as tyranny. This changing fortune of a civilization, this vast and perplexing history, was caught in miniature in the changing relation between the concept t'ienhsia and the concept kuo. T'ien-hsia signifies "the (Chinese) Empire"alternatively, "the world"; as t'ien-hsia, China is the world. And kuo is a local political unit, a part of "the Empire" in classical times, and in the modern world, "the nation." But the respective meanings of t'ien-hsia and kuo are not really revealed in these simple, self-sufficient English equivalents; for at either end of this history, the definition of either term implies a reference to the other, a comparison with the other. In the earlier time it was its contrast with kuo, the regime of power, which defined the t'ien-bsia as the regime of value. But the claims of value are absolute, and if their justice comes to be doubted, respect for these claims will seem the mark of servility, not civilization. It was its contrast, then, with t'ien-hsia-preconception, dictation-which defined the kuo, at the later date, as an area of untraditional free inquiry. Just as China persists but changes, the link between t'ienhsia and kuo persists while something changes their connotations and the degree of esteem accorded to each. What works these changes is something unchanging itself: the Chinese need of a China which no defeat may compromise. In the seventeenth century, the Manchus had conquered the Chinese political power, so China as t'ien-hsia, unimpeachable, civilization in the abstract, was the China which the van-