cssi/SciSciGPT-SciSciNet huggingface dataset:
The Return of von Liebig's “Law of the Minimum”

The development of optimal fertilizer recommendations requires a renewed collaborative effort between agronomists and agricultural economists. The purpose of this study is to emphasize the direction of this interdisciplinary effort in the area of crop response analysis. Using information from two separate experiments [corn (Zea mays L.) response to N and P fertilization and cotton lint (Gossypium hirsutum) response to N and irrigation water], it is shown that the best response model is a von Liebig specification, more commonly known as the law of the minimum. When the selection of a statistical specification is made among models that do not share the parameter space, hypothesis testing cannot be done by means of the familiar F-test and likelihood ratio. The selection of the von Liebig specification (chosen against square-root polynomial and Mitscherlich-Baule models) is, thus, made on the basis of a rigorous statistical analysis using a nonnested hypothesis approach. Giannini Foundation Research Paper no. 1021.
An open mapping theorem for basis separating maps

Abstract As a consequence of the open mapping theorem, a continuous linear bijection H :X→Y between Banach spaces X and Y must be a linear homeomorphism. The main result of this article (Theorem 9) is similar in form but makes no continuity assumptions on H : If X and Y have symmetric Schauder bases (see before Theorem 9 for the definition), then a “basis separating” linear bijection H is a linear homeomorphism. Given Banach spaces X and Y with Schauder bases { x n } and { y n }, respectively, we say that H :X→Y , H(∑ n∈ N x(n)x n )=∑ n∈ N Hx(n)y n , is basis separating if for all elements x=∑ n∈ N x(n)x n and y=∑ n∈ N y(n)x n of X , x ( n ) y ( n )=0 for all n∈ N implies that Hx ( n ) Hy ( n )=0 for all n∈ N . We show that associated with a linear basis separating map H , there is a support map h : N → N ∞ . The support map enables us to develop a canonical form (Theorem 4) for basis separating maps that plays a crucial role in the development of the main results.
Time-optimal control in dc-dc converters: A maximum principle perspective

In this paper, we present an analytical framework to investigate time-optimal trajectories in dc-dc buck, boost, and buck-boost converters using Pontryagin's maximum principle. Particularly, we evaluate cases where a time-optimal transfer of converter states can be achieved with a single switching action, and furthermore, determine if such a control can be uniquely synthesized.
Transoral laser microsurgery for recurrent laryngeal and pharyngeal cancer.

Study Design and Setting A two-center prospective case series analysis. Patients One hundred fourteen patients with previously treated laryngeal or pharyngeal squamous cell carcinoma who underwent salvage transoral laser microsurgery (TLM). Interventions TLM in 114 patients, neck dissection in 22 (19%) patients, adjuvant radiotherapy in 12 (11%) patients. Results Ninety-one (80%) patients had recurrent primary tumors whereas 23 (20%) patients had second primary tumors occur within a previously irradiated field. The minimum follow-up was 1 year (median, 3 years). The distribution of tumor location was oropharynx 52 (46%), glottic and subglottic larynx 44 (39%), supraglottic larynx 11 (10%), and pyriform/hypopharynx 7 (6%). Overall, three-year local and locoregional control estimates were 70 percent and 67 percent, respectively; and three-year survival and disease-free survival estimates were 62 percent and 64 percent, respectively. The average duration of hospitalization was 2.3 days. Four (3.5%) patients had significant postoperative bleeding. Two ( Conclusions Transoral laser microsurgery offers select patients an attractive alternative salvage surgical therapy to the recurrent and second primary tumor site.
Acoustic radiation force acting on elastic and viscoelastic spherical shells placed in a plane standing wave field.

Abstract The theory of the acoustic radiation force acting on elastic spherical shells suspended in a plane standing wave field is developed in relation to their thickness and the content of their hollow regions. The theory is modified to include the effect of a hysteresis type of absorption of compressional and shear waves in the material. The fluid-loading effect on the acoustic radiation force function Yst is analyzed as well. Results of numerical calculations are presented for a number of elastic and viscoelastic materials, with the hollow region filled with water or air. These results show how the damping due to absorption, the change of the interior fluid inside the shells’ hollow regions, and the exterior fluid surrounding their structures, affect the acoustic radiation force.
Complete spin-transfer measurements for inelastic polarized proton scattering from 12C.

Complete spin-transfer observables for the two lowest ${1}^{+}$ levels in $^{12}\mathrm{C}$ have been studied with incident protons of 500 MeV. Outgoing protons were detected with an energy resolution of 120 keV at laboratory angles of 3.5\ifmmode^\circ\else\textdegree\fi{}, 5.0\ifmmode^\circ\else\textdegree\fi{}, 7.5\ifmmode^\circ\else\textdegree\fi{}, 9.5\ifmmode^\circ\else\textdegree\fi{}, and 12.5\ifmmode^\circ\else\textdegree\fi{}. Angular distributions of differential cross sections, analyzing powers, and the individual spin observables for each ${1}^{+}$ state are recombined into three transverse and one longitudinal partial differential cross section as well as the spin-sum and spin-difference functions. Results are compared with model calculations and electron-scattering data. Information about experimental quantities not accessible in electron scattering is also discussed.
Income per Natural: Measuring Development for People Rather Than Places

It is easy to learn the average income of a resident of El Salvador or Albania. But there is no systematic source of information on the average income of a Salvadoran or Albanian. We estimate a new statistic: income per natural—the mean annual income of all people born in a given country, regardless of where those people now reside. Income per natural often differs substantially from income per resident, both in its mean and in its distribution. A large part of this difference is caused by movement across borders. Indeed, for people from a number of developing countries, departing their country of birth is one of the most important sources of poverty reduction and material advancement. If economic development is that which raises human well-being, then crossing international borders is not an alternative to economic development; it is a form of economic development.
Lactate metabolism in anoxic turtles: an integrative review

Painted turtles can accumulate lactic acid to extremely high concentrations during long-term anoxic submergence, with plasma lactate exceeding 200 mmol l−1. The aims of this review are twofold: (1) To summarize aspects of lactate metabolism in anoxic turtles that have not been reviewed previously and (2) To identify gaps in our knowledge of turtle lactate metabolism by comparing it with lactate metabolism during and after exercise in other vertebrates. The topics reviewed include analyses of lactate’s fate during recovery, the effects of temperature on lactate accumulation and clearance, the interaction of activity and recovery metabolism, fuel utilization during recovery, stress hormone responses during and following anoxia, and cellular lactate transport mechanisms. An analysis of lactate metabolism in anoxic turtles in the context of the ‘lactate shuttle’ hypothesis is also presented.
Examining Patterns of Political, Social Service, and Collaborative Involvement of Religious Congregations: A Latent Class and Transition Analysis

This investigation examines typologies of congregations based on patterns of congregational political and social service activities and collaborative partners. Based on a latent class analysis of a national random sample of 2,153 congregations, results indicated four distinct types of congregations with unique patterns of political, social service, and collaborative partnerships labeled: (a) Active, (b) Not Active, (c) Social Service Not Political, and (d) Political Not Social Service. Moreover, congregational characteristics such as religious tradition and clergy characteristics predicted membership in certain types. A latent transition analysis using an additional 262 congregations revealed distinct patterns of how congregations changed types across a nine year period. Results showed both congregational continuity (e.g., Not Active congregations remained Not Active) and change (e.g., Active congregations were likely to change type membership). This study advances congregational research by examining congregational types, what predicts certain types, and how congregations change types across time. Implications for future research and partnership with religious congregations also are discussed.
Cytochrome b5 reductase: Role of the si-face residues, proline 92 and tyrosine 93, in structure and catalysis

The conserved sequence motif “RxYTSxxSN” coordinates flavin binding in NADH:cytochrome b5 reductase (cb5r) and other members of the flavin transhydrogenase superfamily of oxidoreductases. To invest...
Fatty acid profiles of orange and tangor juice sac lipids

Abstract Fatty acids from the juice sacs of four orange varieties from early season harvest, one variety from mid- and one variety from late season, and two tangors were quantitatively determined and it was found that the five major fatty acids, viz. palmitic, palmitoleic, oleic, linoleic and linolenic, comprised more than 92 per cent of all acids. There appeared to be no correlation between the major fatty acids and the harvest season of the various orange varieties. The two tangors were distinctly different from the oranges in both their major and minor fatty acid profiles. A theory is proposed for the occurrence of specific iso- and anteiso-branched acids in citrus.
Electron microscopical observations on early sialoliths in a human submaxillary gland

Abstract Specimens of human submaxillary gland were examined in the electron microscope. The intercalated duct cells were found to be pyramidal in form, and to contain mucous droplets in their apical cytoplasm. The cells are smooth in outline, and lack the membrane specializations commonly associated with ion and water transport. No specific function could be ascribed to these cells. In specimens of submaxillary gland obtained from one patient, early sialoliths were observed in the lumina of some of the intercalated and striated ducts. These sialoliths are composed of two moieties—one crystalline, the other nondashcrystalline. The crystalline component consists of numerous plate-like crystals, which measure 500A–1500A in length and about 65A in thickness and which closely resemble the hydroxyl apatite crystals seen in dentine, enamel and bone. The crystals are disposed in various arrangements in relation to the noncrystalline component, which consists of a finely fibrillar and stippled material. No sites of intracellular calcification were observed.
Color perception and deafness: College-level comparisons

The performance of three groups of college-level subjects, deaf students, normal-hearing students, and Art students, were compared on nine tests involving color perception and color-verbal materials including (a) Color-Form Sorting, (b) Color-Form Pointing, (c) Color-Word Meaning, (d) Color-Pair Preferences (N=3), and (e) Color-Word Interference (N=3). Color perception differences between the deaf and the hearing groups were not substantiated: deaf and hearing groups differed only on tests involving verbal materials. The Deaf differed more from the Art students than from the Hearing.
Population variation in spawning current speed selection in the blacktail shiner, Cyprinella venusta (Pisces: Cyprinidae)

Many stream fishes lay demersal eggs. Some species simply scatter the eggs across the substrate, but many place the eggs in protected sites such as crevices (e.g., Cyprinidae:Cyprinella). Eggs laid in crevices may experience increased development times or lower embryo survival due to reduced water exchange rates compared to more open egg deposition sites. If so, the presence of an appreciable current near the crevice may be important for insuring water exchange. However, currents that are too strong may prevent complete insemination or prevent the eggs from adhering to the substratum before they are washed from the crevice. Thus, current speed preferences for spawning may be under strong stabilizing selection. Representatives of four populations of a crevice spawning stream fish (blacktail shiner,Cyprinella venusta), representing environments ranging from a swift stream to a lake, were studied in stream tanks to evaluate female spawning current use. The observed frequency of use of spawning currents was significantly different from random in all populations. Low current speeds were generally avoided, and a speed of ca. 30 cm sec−1 was used most often. However, significant differences were observed among populations, and the variation correlated well with the apparent range of current speeds found in the four environments. Although other possible explanations cannot be dismissed, the results are consistent with the hypothesis that the populations have become adapted to their local current regimes.
Analysis of a Block Red-Black Preconditioner Applied to the Hermite Collocation Discretization of a Model Parabolic Equation

We are concerned with the numerical solution of a model parabolic partial differential equation (PDE) in two spatial dimensions, discretized by Hermite collocation. In order to efficiently solve the resulting systems of linear algebraic equations, we choose the Bi-CGSTAB method of van der Vorst (1992) with block Red-Black Gauss-Seidel (RBGS) preconditioner. In this article, we give analytic formulae for the eigenvalues that control the rate at which Bi-CGSTAB/RBGS converges. These formulae, which depend on the location of the collocation points, can be utilized to determine where the collocation points should be placed in order to make the Bi-CGSTAB/RBGS method converge as quickly as possible. Along these lines, we discuss issues of choice of time-step size in the context of rapid convergence. A complete stability analysis is also included. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17:584–606, 2001
Application of distractive forces to the small intestine: defining safe limits.

Background Distraction enterogenesis is a novel method for increasing small bowel length by the application of linearly directed forces. However, the magnitude of distractive forces that human and animal small bowel can safely withstand is unknown. Methods Acute ex vivo force-displacement curves for human (n = 5) and pig (n = 6) small intestine (with and without mesentery) were made by applying increasing amounts of distractive forces to bowel immersed in normal saline (39°C). Progressive load was applied until gross disruption of the tissue was detected, or the applied force reached 1000 gram-force (gf). Histology was used to detect evidence of load-induced damage. In vivo blood flow to pig bowel with distractive loads (30–200 gf) was measured by laser Doppler. Results The relationship between the level of force and degree of displacement was linear. The presence of a mesentery increased stiffness of pig bowel, but did not affect human bowel. Gross tissue disruption in pig and human tissue was seen at forces between 235 and 295 gf, respectively. However, in grossly undamaged areas, histology was unchanged even after application of higher loads. With in vivo testing, mesenteric blood flow was present up to 200 gf; however, blood flow to the bowel wall was reduced to undetectable levels at loads exceeding 100 gf. Conclusions While whole bowel tissue may tolerate greater applied loads, blood flow to the bowel wall was compromised at loads over 100 gf, suggesting that any higher forces place the bowel at risk for ischemia. These measurements will help guide the clinical application of distraction enterogenesis.
Necrosis After Craniospinal Irradiation: Results From a Prospective Series of Children With Central Nervous System Embryonal Tumors

Purpose Necrosis of the central nervous system (CNS) is a known complication of craniospinal irradiation (CSI) in children with medulloblastoma and similar tumors. We reviewed the incidence of necrosis in our prospective treatment series. Patients and Methods Between 1996 and 2009, 236 children with medulloblastoma ( n = 185) or other CNS embryonal tumors ( n = 51) received postoperative CSI followed by dose-intense cyclophosphamide, vincristine, and cisplatin. Average risk cases ( n = 148) received 23.4 Gy CSI, 36 Gy to the posterior fossa, and 55.8 Gy to the primary; after 2003, the treatment was 23.4 Gy CSI and 55.8 Gy to the primary. All high-risk cases ( n = 88) received 36-39.6 Gy CSI and 55.8 Gy primary. The primary site clinical target volume margin was 2 cm (pre-2003) or 1 cm (post-2003). With competing risk of death by any cause, we determined the cumulative incidence of necrosis. Results With a median follow-up of 52 months (range, 4-163 months), eight cases of necrosis were documented. One death was attributed. The median time to the imaging evidence was 4.8 months and to symptoms 6.0 months. The cumulative incidence at 5 years was 3.7% ± 1.3% ( n = 236) for the entire cohort and 4.4% ± 1.5% ( n = 196) for infratentorial tumor location. The mean relative volume of infratentorial brain receiving high-dose irradiation was significantly greater for patients with necrosis than for those without: ≥50 Gy (92.12% ± 4.58% vs 72.89% ± 1.96%; P =.0337), ≥52 Gy (88.95% ± 5.50% vs 69.16% ± 1.97%; P =.0275), and ≥54 Gy (82.28% ± 7.06% vs 63.37% ± 1.96%; P =.0488), respectively. Conclusions Necrosis in patients with CNS embryonal tumors is uncommon. When competing risks are considered, the incidence is 3.7% at 5 years. The volume of infratentorial brain receiving greater than 50, 52, and 54 Gy, respectively, is predictive for necrosis.
Mother Tongues and Language Planning in Africa

proposed earlier. The informal sites of production that youths explore and exploit in the making of fusion music provide alternatives to the conventional classroom. These alternative sites potentially have implications for issues such as social exclusion and participation because of their open and inclusive nature. In addition, the code of practice in such alternative sites of knowledge production and language teaching and learning is likely to be more accommodating, less restrictive, and a direct challenge to the hegemony that derives from the existing hierarchy of languages in education. My final word is that the legitimacy of AL as a discipline is tied to our ability as practitioners to think liberally beyond simple binary oppositions of ideological camps like north/south, native/nonnative speakers, even Western/non-Western. I do not mean to say that no concrete evidence of such oppositions appears from time to time, but to operate within such a framework, the discipline runs the risk of being locked in a grid that permanently disadvantages the weaker group of the pair in opposition. Besides, oppositions erroneously project a semblance of equality between the constitutive elements of a group whereas, in reality, they may be as diverse as can possibly be imagined. Thus, although identifying and describing non-Western perspectives in AL remains a legitimate pursuit, applied linguists must proceed with caution to maintain sight of differences within the category itself. We must acknowledge and respond specifically to the complex and diverse contexts from which the discipline's issues arise and, when necessary, redefine its hitherto Western-serving tools as I have attempted with CS.
Radiobiological studies of a high‐energy modulated proton beam utilizing cultured mammalian cells

The modulated, 160-MeV proton beam produced by the Harvard Cyclotron has been examined in detail for its ability to kill mammalian cells as assayed by colony forming ability. Using two different cell exposure techniques, the characteristics of position and total dose in producing cell death in two aneuploid cell lines selected for their radiobiological relevance have been determined. The parameters which describe the survival curves after proton or 60Co irradiation show no statistical differences, except on the distal portion of the final Bragg peak of the proton beam, where RBE increases to approximately 1.4. This increase in RBE results in extending the cell killing effect of the beam by approximately 2 mm. This effect may be of practical significance in the irradiation of tissue such as the pituitary where the position of the Bragg peak is of great importance. The overall killing efficiency ratio between the modulated high-energy proton beam and 60Co γ rays was 1.00 ± .01 (standard error).
The impact of limited English proficiency and physician language concordance on reports of clinical interactions among patients with diabetes: The DISTANCE study

Abstract Objective To assess the association of limited English proficiency (LEP) and physician language concordance with patient reports of clinical interactions. Methods Cross-sectional survey of 8638 Kaiser Permanente Northern California patients with diabetes. Patient responses were used to define English proficiency and physician language concordance. Quality of clinical interactions was based on 5 questions drawn from validated scales on communication, 2 on trust, and 3 on discrimination. Results Respondents included 8116 English-proficient and 522 LEP patients. Among LEP patients, 210 were language concordant and 153 were language discordant. In fully adjusted models, LEP patients were more likely than English-proficient patients to report suboptimal interactions on 3 out of 10 outcomes, including 1 communication and 2 discrimination items. In separate analyses, LEP-discordant patients were more likely than English-proficient patients to report suboptimal clinician–patient interactions on 7 out of 10 outcomes, including 2 communication, 2 trust, and 3 discrimination items. In contrast, LEP-concordant patients reported similar interactions to English-proficient patients. Conclusions Reports of suboptimal interactions among patients with LEP were more common among those with language-discordant physicians. Practice implications Expanding access to language concordant physicians may improve clinical interactions among patients with LEP. Quality and performance assessments should consider physician–patient language concordance.
Agency and structure: Catholic women and educational provision in early-twentieth-century Chicago

Abstract This article examines the images and words used by Catholic women educators and students in Chicago Catholic high schools and colleges during the 1910s to the early 1940s in the USA during a time of great change in the role of women in American society. It considers the social and religious contexts in which these women lived, taught, and learned and how their choices and experiences were shaped by this milieu. This study offers a sense of the many ways Catholic women demonstrated agency, taking action to both reinforce and challenge the traditional roles stipulated by their Catholic beliefs. It argues that through this agency, Catholic women religious and their students forged greater access to higher education and a wider range of professional options.
The strange persistence of consumer surplus

Despite its abandonment in theoretical work, a literature search shows that variation in consumer surplus (VCS) is the overwhelming choice in applied work – not compensating variation (CV) or equivalent variation (EV). How can this be explained? Besides the obvious ease of computation, there are three good reasons for the persistence of VCS. (1) The Willig bounds on VCS usually give close upper and lower bounds on CV and EV, respectively, and are thus conservative in the estimation of EV. (2) Without integrability, all three measures are inaccurate. Common quasi-linear utility assumptions for VCS, however, imply integrability. (3) Even with integrability, the expected values of highly nonlinear CV and EV measures cannot be determined by substituting prices or quantities into the estimated equations; simulations are required. Thus, VCS is not only simpler, it may also be more accurate.
Plant reproduction and environmental noise: How do plants do it?

Plant populations exhibit a wide continuum of reproductive behavior, ranging from nearly constant reproductive output on one end to the extreme of masting (synchronized, highly variable reproduction) on the other. Here, we show that including variability (noise) in density-dependent pollen limitation in current models for pollen-limited plant reproduction may produce any behavior on this continuum. We previously showed that (large) variability in pollination efficiency (a related phenomenon) may induce masting in non-pollen-limited plant populations. Other modeling studies have shown that including variability in accumulated resources (and/or the threshold for reproduction) may induce masting, but do account for masting in non-pollen-limited plant populations. Thus, our results suggest that the range of plant reproductive behavior may be explained with the simple resource budget model combined with the biological realism of variability in density-dependent pollen limitation. This is a specific example of an important functional consequence of the interactions between stochasticity and nonlinearity, and highlights the importance of carefully considering both the biological basis and the mathematical effects of the noise term.
New Sports What is So Punk about Snowboarding

The life cycle of a new sport, and its cultural implications, is apparent in the sport of snowboarding. Snowboarding was born in youthful resistance to the popular sport of skiing and the values of...
Yellow fever: ecology, epidemiology, and role in the collapse of the Classic lowland Maya civilization.

Mystery has long surrounded the collapse of the Classic lowland Mayan civilization of the Peten region in Guatemala. Recent population reconstructions derived from archaeological evidence from the central lowlands show population declines from urban levels of between 2.5 and 3.5 million to around 536,000 in the two hundred year interval between 800 A.D. and 1000 A.D., the period known as the Classic Maya Collapse. A steady, but lesser rate of population decline continued until the time of European contact. When knowledge of the ecology and epidemiology of yellow fever and its known mosquito vectors are compared with what is known of the ecological conditions of lowland Guatemala as modified by the Classic Maya, provocative similarities are observed. When infection and mortality patterns of more recent urban yellow fever epidemics are used as models for a possible series of Classic Maya epidemics, a correlation is noted between the modeled rate of population decline for a series of epidemics, and population decline figures reconstructed from archaeological evidence.
Determining pentaquark quantum numbers from strong decays

Assuming that the recently observed {Theta}{sup +} and {Xi}{sup --} are members of an anti-decuplet of SU(3), decays to ground state baryons and mesons are calculated using an effective Lagrangian which incorporates chiral and SU(3) symmetry. We consider the possible quantum number assignments J{sup {Pi}} = 1/2 {sup {+-}} {center_dot} 3/2 {sup {+-}} and calculate ratios of partial widths. The branching ratios of exotic cascades can be used to discriminate between even and odd parity pentaquarks.
Effects of queen mandibular pheromone on nestmate recognition in worker honeybees, Apis mellifera

The ability to distinguish between members of a social group and unfamiliar individuals is a critical element of social behaviour. Social insects can differentiate between nestmates and non-nestmates via recognition cues, which in most species are cuticular hydrocarbons. Cuticular hydrocarbon patterns are altered by genotype and environmental conditions, but it is unclear whether colony social conditions can also affect nestmate interactions. Honeybee queens produce pheromones that regulate many aspects of worker behaviour, physiology and colony organization. A five-component blend, queen mandibular pheromone (QMP), produces many of the effects of a live queen. We found that QMP treatment alters how resident bees interact with intruder bees, based on standard nestmate recognition assays. However, QMP does not appear to alter the ability of bees to distinguish between nestmates and non-nestmates, or general aggression levels. Rather, QMP exposure significantly alters cuticular hydrocarbon patterns of worker bees, suggesting that QMP-treated nestmates are no longer recognized as nestmates by untreated bees, and vice versa. Thus, queen pheromone can have significant effects on nestmate recognition and interactions in honeybees, which may be important for colony cohesion.
Analysis of elastically coupled shells on elastic foundation by hybrid method

Abstract The theory governing the hybrid analysis computer program HYBOS is derived and presented in adequate detail for full comprehension of the method and assumptions involved. A brief description of the computer program is given and a nontrivial problem is solved to demonstrate the program capabilities. It is believed that HYBOS represents the most comprehensive tool available as of today, in linear elasticity, to analyze axisymmetric structures for non-symmetric loadings of thermal and mechanical origins.
Paternity and gene dispersal in limber pine (Pinus flexilis James).

This study provides empirical information on intrapopulation gene dispersal via pollen, the size of genetic 'neighbourhoods', and interpopulation gene flow in a long-lived conifer, limber pine (Pinus flexilis). We used allozyme loci for a paternity analysis of 518 seeds produced in an isolated population of limber pine located in north-eastern Colorado, U.S.A., separated by 2 km from the nearest conspecific trees and nearly 100 km from populations in the Rocky Mountains. We also used indirect techniques (FST analyses) to estimate gene flow rates among subdivisions of the study population and among five widely separated populations. Within the main study population limber pine exhibited a polymorphism level of 50%, observed heterozygosity of 0.159, and 2.36 alleles per polymorphic locus. Mountain populations were slightly more variable. The main study population showed significant differentiation in allozymes among neighbouring subpopulations. The mean FST was 0.031 and the gene flow rate among subpopulations was estimated as 7.8 migrants per generation. Among widely separated populations the mean FST was 0.035 and the gene flow rate was estimated as 6.9 migrants per generation. The paternity analysis indicated a best estimate of 6.5% pollen immigration (minimum 1.1%) from populations 2 km to 100+ km away. For 4% of the seeds examined, paternity could be ascribed to a single tree in the study population. Fractional paternity and likelihood methods were used to estimate pollen dispersal distances for the remainder of the seeds. Mean pollen dispersal distance was estimated at 140 m using the fractional method, similar to results from the other techniques. This compares with a mean distance of 172 m between potential mates. These results suggest near-panmictic pollen dispersal over this population, which covers about 15 ha. The observed allozyme differences and surprisingly low estimates of among-subpopulation gene flow are ascribed to a probable restriction of gene dispersal by seeds.
The Use of Ninth-Grade Early Warning Indicators to Improve Chicago Schools

Chicago has been in the forefront of the country in its use of 9th-grade indicators of dropout. Catalyzed by the development of the freshman on-track indicator and research around it, Chicago school administrators, central office personnel, and external partners have developed a number of mechanisms using 9th-grade indicators to stimulate school improvement. This article describes 3 ways in which early warning indicators are useful for improving student achievement: (a) focusing conversations and efforts on actionable problems; (b) identifying students for intervention; and (c) using indicator patterns to address low performance in a strategic way. Examples from high schools in Chicago suggest that knowledge of the on-track indicator and its use in district accountability were not enough to change practice. However, the availability of data tools that make it easy to act on information about on-track rates have changed the ways in which teachers and school staff interact with each other, students, and par...
Society for Maternal-Fetal Medicine meeting presentations: what gets published and why?

Abstract Objectives The purpose of this study was to determine the publication rate and factors influencing publication among presentations to the Society for Maternal-Fetal Medicine (SMFM) from 1991 through 2000. Study design Plenary presentations matched to an equal number of concurrent presentations were examined for publication rate and associated factors by univariable and multivariable analysis, respectively. The National Library of Medicine online library, PubMed, was searched for authors and/or subject to determine publication. Various characteristics of meeting abstracts were examined related to eventual publication. Results There were 88 presentations in each group, with plenary presentations published at a higher rate (81% vs 56%, P = .004) and in more prominent journals (21% vs 1%, P Conclusion The SMFM meeting selection process identifies presentations likely to be published, and therefore presumably of high quality. The overall publication rate of concurrent presentations appears to be better than that of many other medical society meetings.
The effects of tetraphenylboron on spontaneous transmitter release at the frog neuromuscular junction.

Abstract 1 The effects of tetraphenylboron (TPB) on spontaneous transmitter release were studied in the frog sartorius muscle preparation. 2 TPB (0.001-1 mM) produced a time-dependent increase in miniature endplate potential (m.e.p.p.) activity that was not sustained. TPB (0.1 mM) produced similar effects on m.e.p.p. frequency in normal Ringer solutions, in the absence of Ca2+ or Cl- and in the presence of excess Ca2+ and of tetrodotoxin. The effect of TPB (0.01 mM) was reduced but not abolished in the absence of Ca2+. 3 As m.e.p.p. frequency fell from its peak level in TPB (0.04 mM) m.e.p.p. amplitude was reduced. The reduction of m.e.p.p. amplitude was not prevented by choline (30-300 muM). 4 When m.e.p.p. activity fell below the noise level in the presence of TPB (0.1 mM), lanthanum (0.5 mM) was ineffective in promoting measurable m.e.p.p. activity. 5 The effects of TPB were slowly reversible by washing. 6 The results indicate that TPB acts to reduce the nerve terminal stores of acetylcholine, probably by a combination of rapid release and concomitant inhibition of transmitter storage.
Understanding Perceived Image Quality: New Applications for Verbal Protocol Methodology

The present study investigated the effectiveness of ‘cued retrospective verbalization’ used in combination with eye-movement recordings as memory aids to study image quality evaluation of display products. That is, recordings of eye movements during image quality judgments were played back as cues for recalling and verbalizing thoughts which occurred during prior image evaluation. The study also examined the consistency of subjects' image quality evaluation responses over time and whether retrospective verbalization influenced and altered subsequent preference. The experiment consisted of two sessions separated by a 60-hour interval. Subjects in the experimental condition performed retrospective verbalization in both sessions whereas subjects in the control condition did so only in the second session. Judgments of perceptual quality were stable over time, and there was no indication that cued retrospective verbalization influenced subsequent perceptual evaluation. Moreover, subjects in the experimental co...
Identification of Two Topologically Independent Domains in RAG1 and Their Role in Macromolecular Interactions Relevant to V(D)J Recombination

V(D)J recombination is instigated by the recombination-activating proteins RAG1 and RAG2, which catalyze site-specific DNA cleavage at the border of the recombination signal sequence (RSS). Although both proteins are required for activity, core RAG1 (the catalytically active region containing residues 384-1008 of 1040) alone displays binding specificity for the conserved heptamer and nonamer sequences of the RSS. The nonamer-binding region lies near the N terminus of core RAG1, whereas the heptamer-binding region has not been identified. Here, potential domains within core RAG1 were identified using limited proteolysis studies. An iterative procedure of DNA cloning, protein expression, and characterization revealed the presence of two topologically independent domains within core RAG1, referred to as the central domain (residues 528-760) and the C-terminal domain (residues 761-980). The domains do not include the nonamer-binding region but rather largely span the remaining relatively uncharacterized region of core RAG1. Characterization of macromolecular interactions revealed that the central domain bound to the RSS with specificity for the heptamer and contained the predominant binding site for RAG2. The C-terminal domain bound DNA cooperatively but did not show specificity for either conserved RSS element. This domain was also found to self-associate, implicating it as a dimerization domain within RAG1.
Nonlinear dynamics of stiff polymers.

A formalism is presented for the nonlinear dynamics of inextensible stiff polymers within the model of local viscous dissipation. By casting the internal elastic forces in an intrinsic representation, enforcing the constraint of local inextensibility through a Lagrange multiplier function, and utilizing techniques from the differential geometry of curve motion, the dynamics of configurations of arbitrary complexity is reduced to a scalar partial differential equation amenable to analytical and efficient numerical study. As an example, the formalism is applied to the ``folding'' dynamics of stiff polymers with pairwise self-interactions and intrinsic curvature.
A frizzled homolog functions in a vertebrate Wnt signaling pathway

Abstract Background Wnts are secreted proteins implicated in cell–cell interactions during embryogenesis and tumorigenesis, but receptors involved in transducing Wnt signals have not yet been definitively identified. Members of a large family of putative transmembrane receptors homologous to the frizzled protein in Drosophila have been identified recently in both vertebrates and invertebrates, raising the question of whether they are involved in transducing signals for any known signaling factors. Results To test the potential involvement of frizzled homologs in Wnt signaling, we examined the effects of overexpressing rat frizzled-1 (Rfz-1) on the subcellular distribution of Wnts and of dishevelled , a cytoplasmic component of the Wnt signalling pathway. We demonstrate that ectopic expression of Rfz-1 recruits the dishevelled protein – as well as Xenopus Wnt-8 (Xwnt-8), but not the functionally distinct Xwnt-5A – to the plasma membrane. Moreover, Rfz-1 is sufficient to induce the expression of two Xwnt-8-responsive genes, siamois and Xnr -3, in Xenopus explants in a manner which is antagonized by glycogen synthase kinase-3, which also antagonizes Wnt signaling. When Rfz-1 and Xwnt -8 are expressed together in this assay, we observe greater induction of these genes, indicating that Rfz-1 can synergize with a Wnt. Conclusions The results demonstrate that a vertebrate frizzled homolog is involved in Wnt signaling in a manner which discriminates between functionally distinct Wnts, which involves translocation of the dishevelled protein to the plasma membrane, and which works in a synergistic manner with Wnts to induce gene expression. These data support the likely function of frizzled homologs as Wnt receptors, or as components of a receptor complex.
Isoform-specific proteasomal degradation of Rbfox3 during chicken embryonic development

Rbfox3, a neuron-specific RNA-binding protein, plays an important role in neuronal differentiation during development. An isoform Rbfox3-d31, which excludes the 93-nucleotide cassette exon within the RNA recognition motif of chicken Rbfox3, has been previously identified. However, the cellular functions of Rbfox3-d31 remain largely unknown. Here we find that Rbfox3-d31 mRNA is highly expressed during the early developmental stages of the chicken embryo, while Rbfox3-d31 protein is barely detected during the same stage due to its rapid degradation mediated by the ubiquitin-proteasome pathway. Importantly, this degradation is specific to the Rbfox3-d31 isoform and it does not occur with full-length Rbfox3. Furthermore, suppression of Rbfox3-d31 protein degradation with the proteasome inhibitor MG132 attenuates the splicing activity of another Rbfox family member Rbfox2 by altering the subcellular localization of Rbfox2. These results suggest that Rbfox3-d31 functions as a repressor for the splicing activity of the Rbfox family and its protein level is regulated in an isoform-specific manner in vivo.
The potential unreliability of indium 111 oxine labeling in studies of endothelial cell kinetics

The current widespread use of indium 111 oxine for labeling endothelial cells to study their interaction with various bioprosthetic flow surfaces presupposes a high retention of the radioisotope within the cell and a lack of significant adherence of any marker released from the cell to the surface under study. We measured the loss of indium 111 from freshly harvested, canine, venous endothelial cells, and their viability in cell culture, for varying intervals up to 24 hours. At prescribed intervals, aliquots of the radiolabeled endothelial cell suspension were centrifuged, and the supernatant was separated from the cell pellet. The relative radioactivity of each was measured in a gamma well counter and the spontaneous loss of marker from the endothelial cells was calculated. Spontaneous loss of indium 111 was 7.8% +/- 1.9% at 1 hour and 47.6% +/- 1.8% at 24 hours. Loss of activity was virtually constant between 14 and 24 hours. Endothelial cell viability was 80% at 24 hours. We next studied the in vitro affinity of indium 111 oxine and indium 111 transferrin for untreated expanded polytetrafluoroethylene vascular grafts and for similar grafts treated with two surfactants commonly used to increase the "wetability" of expanded polytetrafluoroethylene, a nonionic sufectant (Nonidet) and tridodecylmethylammonium chloride, and with two glycoproteins, fibronectin and basement membrane gel. A minimum of three graft segments were studied in each group. The affinity of graft material for indium 111, in both its oxine and transferrin complex, was significantly increased by treating the graft with a wetting agent, and it was further increased by the addition of a glycoprotein.(ABSTRACT TRUNCATED AT 250 WORDS)
A toxicity testing system for exposing small invertebrates and fish to short square-wave concentrations of chlorine☆☆☆

Abstract We describe a flow-through toxicity testing system which can be manipulated to deliver a “square-wave” chlorine concentration curve for short exposure times to small invertebrates and fish. The system consists of a series of test containers, each with dual input delivery lines (dilution water alone or toxicant plus dilution water), a syringe pump for addition of toxicant to one of the two delivery lines, a constant head tank, and reservoir tanks. Control of valves on the delivery lines and on the test chamber drains caused chlorine concentration to rise to the target value in ⩽ 1 min and to fall below detection limits (0.01 mg 1−1) in ⩽ 2 min at the beginning and end of the exposure period, respectively. Using this system, we determined the toxicity of 30- and 60-min exposures of total residual chlorine (85–95% free residual to Daphnia magna and Gambusia affinis. The 30- and 60-min LC 50 values were 0.097 and 0.063 mg 1−1, respectively, for Daphnia and 1.59 and 0.84 mg 1−1, respectively, for Gambusia. Use of this (or a similar) system can provide the readily comparable data base which is important for developing chlorine criteria for power plants.
A Poisson-Charlier approximation for nonstationary queues

Abstract In this paper, we develop a new approximation for nonstationary multiserver queues with abandonment. Our method uses the Poisson–Charlier polynomials, which are a discrete orthogonal polynomial sequence that is orthogonal with respect to the Poisson distribution. We show that by appealing to the Poisson–Charlier polynomials that we can estimate the mean, variance, and probability of delay of our nonstationary queueing system with good accuracy. Lastly, we provide a numerical example that illustrates that our approximations are effective.
10.7 Gb/s CWDM system transmission with 8 channels 140 nm bandwidth over 120 km using two SOAs

We demonstrate 8-channel CWDM transmission at 10.7 Gb/s over 120 km of fiber in two different configurations using just two SOAs for wide bandwidth amplification. The total system capacity-distance product is 9.6 Tb/s-km.
Ultrafine ash aerosols from coal combustion: Characterization and health effects ☆

Abstract Ultrafine coal fly-ash particles, defined here as those with diameters less than 0.5 μm, typically comprise less than 1% of the total fly-ash mass. These particles are formed primarily through ash vaporization, nucleation, and coagulation/condensation mechanisms, which lead to compositions notably different compared to other fine or coarse particle fractions formed by fragmentation. Whereas previous studies have focused on health effects of particulate matter with aerodynamic diameters less than 2.5 μm (PM2.5) (including both vaporization and fragmentation modes), this paper reports results of interdisciplinary research focused on both characterization and health effects of primary ultrafine coal ash aerosols alone. Ultrafine, fine, and coarse ash particles were segregated and collected from a coal burned in a 20 kW laboratory combustor and two additional coals burned in an externally heated drop tube furnace. Extracted samples from both combustors were characterized by transmission electron microscopy (TEM), wavelength dispersive X-ray fluorescence (WD-XRF) spectroscopy, Mossbauer spectroscopy, and X-ray absorption fine structure (XAFS) spectroscopy. Pulmonary inflammation was characterized by albumin concentrations in mouse lung lavage fluid after instillation of collected particles in saline solutions and a single direct inhalation exposure. Results indicate that coal ultrafine ash sometimes, but not always, contains significant amounts of carbon, probably soot originating from coal tar volatiles, depending on coal type and combustion device. Surprisingly, XAFS results revealed the presence of chromium and thiophenic sulfur in the ultrafine ash particles. Although the single direct inhalation study failed to reveal significant health effects, the instillation results suggested potential lung injury, the severity of which could be correlated with the carbon (soot) content of the ultrafines. Further, this increased toxicity is consistent with theories in which the presence of carbon mediates transition metal (i.e., Fe) complexes, as revealed in this work by TEM and XAFS spectroscopy, promoting reactive oxygen species, oxidation–reduction cycling, and oxidative stress.