cssi/SciSciGPT-SciSciNet huggingface dataset:
Magnetically-propelled fecal surrogates for modeling the impact of solid-induced shear forces on primary colonic epithelial cells.

Abstract The colonic epithelium is continuously exposed to an array of biological and mechanical stimuli as its luminal contents are guided over the epithelial surface through regulated smooth muscle contraction . In this report, the propulsion of solid fecal contents over the colonic epithelium is recapitulated through noninvasive actuation of magnetic agarose hydrogels over primary intestinal epithelial cultures, in contrast to the vast majority of platforms that apply shear forces through liquid microflow. Software-controlled magnetic stepper motors enable experimental control over the frequency and velocity of these events to match in vivo propulsive contractions, while the integration of standardized well plate spacing facilitates rapid integration into existing assay pipelines. The application of these solid-induced shear forces did not deleteriously affect cell monolayer surface coverage, viability, or transepithelial electrical resistance unless the device parameters were raised to a 50× greater contraction frequency and 4× greater fecal velocity than those observed in healthy humans. At a frequency and velocity that is consistent with average human colonic motility , differentiation of the epithelial cells into absorptive and goblet cell phenotypes was not affected. Protein secretion was modulated with a two-fold increase in luminal mucin-2 secretion and a significant reduction in basal interleukin-8 secretion. F-actin, zonula occludens-1, and E-cadherin were each present in their proper basolateral locations, similar to those of static control cultures. While cellular height was unaffected by magnetic agarose propulsion, several alterations in lateral morphology were observed including decreased circularity and compactness , and an increase in major axis length, which align with surface epithelial cell morphologies observed in vivo and may represent early markers of luminal exfoliation . This platform will be of widespread utility for the investigation of fecal propulsive forces on intestinal physiology, shedding light on how the colonic epithelium responds to mechanical cues.
End-to-End Differentiable Learning of Turbulence Models from Indirect Observations

Abstract The emerging push of the differentiable programming paradigm in scientific computing is conducive to training deep learning turbulence models using indirect observations. This paper demonstrates the viability of this approach and presents an end-to-end differentiable framework for training deep neural networks to learn eddy viscosity models from indirect observations derived from the velocity and pressure fields. The framework consists of a Reynolds-averaged Navier–Stokes (RANS) solver and a neural-network-represented turbulence model, each accompanied by its derivative computations. For computing the sensitivities of the indirect observations to the Reynolds stress field, we use the continuous adjoint equations for the RANS equations, while the gradient of the neural network is obtained via its built-in automatic differentiation capability. We demonstrate the ability of this approach to learn the true underlying turbulence closure when one exists by training models using synthetic velocity data from linear and nonlinear closures. We also train a linear eddy viscosity model using synthetic velocity measurements from direct numerical simulations of the Navier–Stokes equations for which no true underlying linear closure exists. The trained deep-neural-network turbulence model showed predictive capability on similar flows.
New [SU(3)]4 realization of lepton/dark symmetry

Abstract Extending the well-known S U ( 3 ) C × S U ( 3 ) L × S U ( 3 ) R model of quarks and leptons to include a fourth S U ( 3 ) N gauge factor, a new realization is obtained, different from leptonic color, which contains a lepton/dark symmetry with the help of an input Z 4 symmetry. It is seen to encompass a previous extension of the standard model to S U ( 2 ) N lepton symmetry.
Evaluating Relaxations of Logic for Neural Networks: A Comprehensive Study.

Symbolic knowledge can provide crucial inductive bias for training neural models, especially in low data regimes. A successful strategy for incorporating such knowledge involves relaxing logical statements into sub-differentiable losses for optimization. In this paper, we study the question of how best to relax logical expressions that represent labeled examples and knowledge about a problem; we focus on sub-differentiable t-norm relaxations of logic. We present theoretical and empirical criteria for characterizing which relaxation would perform best in various scenarios. In our theoretical study driven by the goal of preserving tautologies, the Lukasiewicz t-norm performs best. However, in our empirical analysis on the text chunking and digit recognition tasks, the product t-norm achieves best predictive performance. We analyze this apparent discrepancy, and conclude with a list of best practices for defining loss functions via logic.
Disparate Impact of Artificial Intelligence Bias in Ridehailing Economy's Price Discrimination Algorithms

Ridehailing applications that collect mobility data from individuals to inform smart city planning predict each trip's fare pricing with automated algorithms that rely on artificial intelligence (AI). This type of AI algorithm, namely a price discrimination algorithm, is widely used in the industry's black box systems for dynamic individualized pricing. Lacking transparency, studying such AI systems for fairness and disparate impact has not been possible without access to data used in generating the outcomes of price discrimination algorithms. Recently, in an effort to enhance transparency in city planning, the city of Chicago regulation mandated that transportation providers publish anonymized data on ridehailing. As a result, we present the first large-scale measurement of the disparate impact of price discrimination algorithms used by ridehailing applications. The application of random effects models from the meta-analysis literature combines the city-level effects of AI bias on fare pricing from census tract attributes, aggregated from the American Community Survey. An analysis of 100 million ridehailing samples from the city of Chicago indicates a significant disparate impact in fare pricing of neighborhoods due to AI bias learned from ridehailing utilization patterns associated with demographic attributes. Neighborhoods with larger non-white populations, higher poverty levels, younger residents, and high education levels are significantly associated with higher fare prices, with combined effect sizes, measured in Cohen's d, of -0.32, -0.28, 0.69, and 0.24 for each demographic, respectively. Further, our methods hold promise for identifying and addressing the sources of disparate impact in AI algorithms learning from datasets that contain U.S. geolocations.
Universality Near the Gradient Catastrophe Point in the Semiclassical Sine-Gordon Equation

We study the semiclassical limit of the sine-Gordon (sG) equation with below threshold pure impulse initial data of Klaus-Shaw type. The Whitham averaged approximation of this system exhibits a gradient catastrophe in finite time. In accordance with a conjecture of Dubrovin, Grava and Klein, we found that in a $\mathcal{O}(\epsilon^{4/5})$ neighborhood near the gradient catastrophe point, the asymptotics of the sG solution are universally described by the Painleve I tritronquee solution. A linear map can be explicitly made from the tritronquee solution to this neighborhood. Under this map: away from the tritronquee poles, the first correction of sG is universally given by the real part of the Hamiltonian of the tritronquee solution; localized defects appear at locations mapped from the poles of tritronquee solution; the defects are proved universally to be a two parameter family of special localized solutions on a periodic background for the sG equation. We are able to characterize the solution in detail. Our approach is the rigorous steepest descent method for matrix Riemann--Hilbert problems, substantially generalizing Bertola and Tovbis's results on the nonlinear Schrodinger equation to establish universality beyond the context of solutions of a single equation.
Definitive hematopoietic stem cells minimally contribute to embryonic hematopoiesis

Hematopoietic stem cells (HSCs) are rare cells that arise in the embryo and sustain adult hematopoiesis. Although the functional potential of nascent HSCs is detectable by transplantation, their native contribution during development is unknown, in part due to the overlapping genesis and marker gene expression with other embryonic blood progenitors. Using single-cell transcriptomics, we define gene signatures that distinguish nascent HSCs from embryonic blood progenitors. Applying a lineage-tracing approach to selectively track HSC output in situ, we find significantly delayed lymphomyeloid contribution. An inducible HSC injury model demonstrates a negligible impact on larval lymphomyelopoiesis following HSC depletion. HSCs are not merely dormant at this developmental stage, as they showed robust regeneration after injury. Combined, our findings illuminate that nascent HSCs self-renew but display differentiation latency, while HSC-independent embryonic progenitors sustain developmental hematopoiesis. Understanding these differences could improve de novo generation and expansion of functional HSCs.
Exact Minimax Estimation for Phase Synchronization

We study the phase synchronization problem with measurements ${Y}= {z}^{\ast} {z}^{\ast{\mathrm {H}}}+\sigma {W}\in \mathbb {C}^{n}\times {n}$ , where ${z}^{\ast}$ is an ${n}$ -dimensional complex unit-modulus vector and ${W}$ is a complex-valued Gaussian random matrix. It is assumed that each entry ${Y}_{jk}$ is observed with probability ${p}$ . We prove that the minimax lower bound of estimating ${z}^{\ast}$ under the squared $\ell _{2}$ loss is $(1- {o}(1))\frac {\sigma ^{2}}{2p}$ . We also show that both generalized power method and maximum likelihood estimator achieve the error bound $(1+ {o}(1))\frac {\sigma ^{2}}{2p}$ . Thus, $\frac {\sigma ^{2}}{2p}$ is the exact asymptotic minimax error of the problem. Our upper bound analysis involves a precise characterization of the statistical property of the power iteration. The lower bound is derived through an application of van Trees’ inequality.
Modulated Periodic Activations for Generalizable Local Functional Representations.

Multi-Layer Perceptrons (MLPs) make powerful functional representations for sampling and reconstruction problems involving low-dimensional signals like images,shapes and light fields. Recent works have significantly improved their ability to represent high-frequency content by using periodic activations or positional encodings. This often came at the expense of generalization: modern methods are typically optimized for a single signal. We present a new representation that generalizes to multiple instances and achieves state-of-the-art fidelity. We use a dual-MLP architecture to encode the signals. A synthesis network creates a functional mapping from a low-dimensional input (e.g. pixel-position) to the output domain (e.g. RGB color). A modulation network maps a latent code corresponding to the target signal to parameters that modulate the periodic activations of the synthesis network. We also propose a local-functional representation which enables generalization. The signal's domain is partitioned into a regular grid,with each tile represented by a latent code. At test time, the signal is encoded with high-fidelity by inferring (or directly optimizing) the latent code-book. Our approach produces generalizable functional representations of images, videos and shapes, and achieves higher reconstruction quality than prior works that are optimized for a single signal.
Rethinking Transformer-Based Set Prediction for Object Detection

DETR is a recently proposed Transformer-based method which views object detection as a set prediction problem and achieves state-of-the-art performance but demands extra-long training time to converge. In this paper, we investigate the causes of the optimization difficulty in the training of DETR. Our examinations reveal several factors contributing to the slow convergence of DETR, primarily the issues with the Hungarian loss and the Transformer cross-attention mechanism. To overcome these issues we propose two solutions, namely, TSP-FCOS (Transformer-based Set Prediction with FCOS) and TSP-RCNN (Transformer-based Set Prediction with RCNN). Experimental results show that the proposed methods not only converge much faster than the original DETR, but also significantly outperform DETR and other baselines in terms of detection accuracy.
Neural Strokes: Stylized Line Drawing of 3D Shapes

This paper introduces a model for producing stylized line drawings from 3D shapes. The model takes a 3D shape and a viewpoint as input, and outputs a drawing with textured strokes, with variations in stroke thickness, deformation, and color learned from an artist's style. The model is fully differentiable. We train its parameters from a single training drawing of another 3D shape. We show that, in contrast to previous image-based methods, the use of a geometric representation of 3D shape and 2D strokes allows the model to transfer important aspects of shape and texture style while preserving contours. Our method outputs the resulting drawing in a vector representation, enabling richer downstream analysis or editing in interactive applications.
Functional transcendence for the unipotent Albanese map

We prove a certain transcendence property of the unipotent Albanese map of a smooth variety, conditional on the Ax-Schanuel conjecture for variations of mixed Hodge structure. We show that this property allows the Chabauty-Kim method to be generalized to higher-dimensional varieties. In particular, we conditionally generalize several of the main Diophantine finiteness results in Chabauty-Kim theory to arbitrary number fields.
Durable Functions: Semantics for Stateful Serverless

Serverless, or Functions-as-a-Service (FaaS), is an increasingly popular paradigm for application development, as it provides implicit elastic scaling and load based billing. However, the weak execution guarantees and intrinsic compute-storage separation of FaaS create serious challenges when developing applications that require persistent state, reliable progress, or synchronization. This has motivated a new generation of serverless frameworks that provide stateful abstractions. For instance, Azure's Durable Functions (DF) programming model enhances FaaS with actors, workflows, and critical sections. As a programming model, DF is interesting because it combines task and actor parallelism, which makes it suitable for a wide range of serverless applications. We describe DF both informally, using examples, and formally, using an idealized high-level model based on the untyped lambda calculus. Next, we demystify how the DF runtime can (1) execute in a distributed unreliable serverless environment with compute-storage separation, yet still conform to the fault-free high-level model, and (2) persist execution progress without requiring checkpointing support by the language runtime. To this end we define two progressively more complex execution models, which contain the compute-storage separation and the record-replay, and prove that they are equivalent to the high-level model.
Long-Term, in-the-Wild Study of Feedback about Speech Intelligibility for K-12 Students Attending Class via a Telepresence Robot

Telepresence robots offer presence, embodiment, and mobility to remote users, making them promising options for homebound K-12 students. It is difficult, however, for robot operators to know how well they are being heard in remote and noisy classroom environments. One solution is to estimate the operator’s speech intelligibility to their listeners in order to provide feedback about it to the operator. This work contributes the first evaluation of a speech intelligibility feedback system for homebound K-12 students attending class remotely. In our four long-term, in-the-wild deployments we found that students speak at different volumes instead of adjusting the robot’s volume, and that detailed audio calibration and network latency feedback are needed. We also contribute the first findings about the types and frequencies of multimodal comprehension cues given to homebound students by listeners in the classroom. By annotating and categorizing over 700 cues, we found that the most common cue modalities were conversation turn timing and verbal content. Conversation turn timing cues occurred more frequently overall, whereas verbal content cues contained more information and might be the most frequent modality for negative cues. Our work provides recommendations for telepresence systems that could intervene to ensure that remote users are being heard.
The low-complexity domain of the FUS RNA binding protein self-assembles via the mutually exclusive use of two distinct cross-β cores

The low-complexity (LC) domain of the fused in sarcoma (FUS) RNA binding protein self-associates in a manner causing phase separation from an aqueous environment. Incubation of the FUS LC domain under physiologically normal conditions of salt and pH leads to rapid formation of liquid-like droplets that mature into a gel-like state. Both examples of phase separation have enabled reductionist biochemical assays allowing discovery of an N-terminal region of 57 residues that assembles into a labile, cross-β structure. Here we provide evidence of a nonoverlapping, C-terminal region of the FUS LC domain that also forms specific cross-β interactions. We propose that biologic function of the FUS LC domain may operate via the mutually exclusive use of these N- and C-terminal cross-β cores. Neurodegenerative disease-causing mutations in the FUS LC domain are shown to imbalance the two cross-β cores, offering an unanticipated concept of LC domain function and dysfunction.
Mechanoreceptor synapses in the brainstem shape the central representation of touch

Mammals use glabrous (hairless) skin of their hands and feet to navigate and manipulate their environment. Cortical maps of the body surface across species contain disproportionately large numbers of neurons dedicated to glabrous skin sensation, in part reflecting a higher density of mechanoreceptors that innervate these skin regions. Here, we find that disproportionate representation of glabrous skin emerges over postnatal development at the first synapse between peripheral mechanoreceptors and their central targets in the brainstem. Mechanoreceptor synapses undergo developmental refinement that depends on proximity of their terminals to glabrous skin, such that those innervating glabrous skin make synaptic connections that expand their central representation. In mice incapable of sensing gentle touch, mechanoreceptors innervating glabrous skin still make more powerful synapses in the brainstem. We propose that the skin region a mechanoreceptor innervates controls the developmental refinement of its central synapses to shape the representation of touch in the brain.
Black-box Adversarial Attacks on Network-wide Multi-step Traffic State Prediction Models

Traffic state prediction is necessary for many Intelligent Transportation Systems applications. Recent developments of the topic have focused on network-wide, multi-step prediction, where state of the art performance is achieved via deep learning models, in particular, graph neural network-based models. While the prediction accuracy of deep learning models is high, these models' robustness has raised many safety concerns, given that imperceptible perturbations added to input can substantially degrade the model performance. In this work, we propose an adversarial attack framework by treating the prediction model as a black-box, i.e., assuming no knowledge of the model architecture, training data, and (hyper) parameters. However, we assume that the adversary can oracle the prediction model with any input and obtain corresponding output. Next, the adversary can train a substitute model using input-output pairs and generate adversarial signals based on the substitute model. To test the attack effectiveness, two state of the art, graph neural network-based models (GCGRNN [1] and DCRNN [2]) are examined. As a result, the adversary can degrade the target model's prediction accuracy up to 54 %. In comparison, two conventional statistical models (linear regression and historical average) are also examined. While these two models do not produce high prediction accuracy, they are either influenced negligibly (less than 3%) or are immune to the adversary's attack.
Pointwise Bounds for Distribution Estimation under Communication Constraints

We consider the problem of estimating a $d$-dimensional discrete distribution from its samples observed under a $b$-bit communication constraint. In contrast to most previous results that largely focus on the global minimax error, we study the local behavior of the estimation error and provide \emph{pointwise} bounds that depend on the target distribution $p$. In particular, we show that the $\ell_2$ error decays with $O\left(\frac{\lVert p\rVert_{1/2}}{n2^b}\vee \frac{1}{n}\right)$ (In this paper, we use $a\vee b$ and $a \wedge b$ to denote $\max(a, b)$ and $\min(a,b)$ respectively.) when $n$ is sufficiently large, hence it is governed by the \emph{half-norm} of $p$ instead of the ambient dimension $d$. For the achievability result, we propose a two-round sequentially interactive estimation scheme that achieves this error rate uniformly over all $p$. Our scheme is based on a novel local refinement idea, where we first use a standard global minimax scheme to localize $p$ and then use the remaining samples to locally refine our estimate. We also develop a new local minimax lower bound with (almost) matching $\ell_2$ error, showing that any interactive scheme must admit a $\Omega\left( \frac{\lVert p \rVert_{{(1+\delta)}/{2}}}{n2^b}\right)$ $\ell_2$ error for any $\delta > 0$. The lower bound is derived by first finding the best parametric sub-model containing $p$, and then upper bounding the quantized Fisher information under this model. Our upper and lower bounds together indicate that the $\mathcal{H}_{1/2}(p) = \log(\lVert p \rVert_{{1}/{2}})$ bits of communication is both sufficient and necessary to achieve the optimal (centralized) performance, where $\mathcal{H}_{{1}/{2}}(p)$ is the R\'enyi entropy of order $2$. Therefore, under the $\ell_2$ loss, the correct measure of the local communication complexity at $p$ is its R\'enyi entropy.
Measuring Sentence-Level and Aspect-Level (Un)certainty in Science Communications

Certainty and uncertainty are fundamental to science communication. Hedges have widely been used as proxies for uncertainty. However, certainty is a complex construct, with authors expressing not only the degree but the type and aspects of uncertainty in order to give the reader a certain impression of what is known. Here, we introduce a new study of certainty that models both the level and the aspects of certainty in scientific findings. Using a new dataset of 2167 annotated scientific findings, we demonstrate that hedges alone account for only a partial explanation of certainty. We show that both the overall certainty and individual aspects can be predicted with pre-trained language models, providing a more complete picture of the author’s intended communication. Downstream analyses on 431K scientific findings from news and scientific abstracts demonstrate that modeling sentence-level and aspect-level certainty is meaningful for areas like science communication. Both the model and datasets used in this paper are released at https://blablablab.si.umich.edu/projects/certainty/.
Laser Light-Sheet Visualization of the Spatial Evolution and Mixing of Coherent Droplet Structures

This paper presents the results of using the laser light-sheet technique to examine the spatial organization of droplets within an electrohydrodynamic spray. This technique is well suited for such sprays in that it can clearly delineate the boundaries of the spray and identify spatially segregated groups of droplets that occur within the spray. The technique further provides a means to quantify the extent of mixing between groups of droplets.
STEM Education in the Foreign Language Classroom with Special Attention to the L2 German Classroom

This thesis tackles the severed relocated and complex issues of foreign language education, with special attention to German as a foreign language, and of STEM education in the K-12, and in some cases K-16, educational system. After exploring the societal and national need for improved STEM and foreign language education programs, the thesis suggests methods of integrating STEM education elements and principles in the foreign language classroom. These methods are provided in chapters about integrating state and national education standards in the STEM fields; core academic subject fields and foreign language teaching; and finally in chapters about the most appropriate and effective pedagogies for successful STEM and foreign language integration. The thesis brings together research about such integration in learning modules and discusses assessment methods, and points toward areas of research. The learning modules and research seek to answer a need to shift education in the direction of an integrative, interdisciplinary approach that supports deeper learning, purpose for student learning, and student interest.
Recognizing City Identity via Attribute Analysis of Geo-tagged Images

After hundreds of years of human settlement, each city has formed a distinct identity, distinguishing itself from other cities. In this work, we propose to characterize the identity of a city via an attribute analysis of 2 million geo-tagged images from 21 cities over 3 continents. First, we estimate the scene attributes of these images and use this representation to build a higher-level set of 7 city attributes, tailored to the form and function of cities. Then, we conduct the city identity recognition experiments on the geo-tagged images and identify images with salient city identity on each city attribute. Based on the misclassification rate of the city identity recognition, we analyze the visual similarity among different cities. Finally, we discuss the potential application of computer vision to urban planning.
Chichibabin amination reaction

Direct amination of pyridines, quinolines, and other N-heterocycles using sodium amide in liquid ammonia.
Reasons for recent marijuana use in relation to use of other illicit drugs among high school seniors in the United States

AbstractObjectives: Studies show that illicit cannabis (marijuana) use is related to use of other illicit drugs and that reasons for use are related to frequency of marijuana use. However, research is needed to examine whether specific reasons for marijuana use are associated with use of other illicit drugs. Methods: Data from recent marijuana-using high school seniors were examined from 12 cohorts of Monitoring the Future (Weighted n = 6481) to examine whether reasons for recent marijuana use are associated with use of eight other illicit drugs. Results: Using “to experiment” decreased odds of reporting use of each drug and using to decrease effects of other drugs increased odds of reporting use of each drug. In multivariable models, using marijuana “to experiment” decreased the odds for reporting use of hallucinogens other than LSD and narcotics other than heroin. Using marijuana for “insight” increased the odds for use of hallucinogens other than LSD, and use due to “boredom” increased the odds for rep...
Neurobiology of Seasonal Life-history Transitions

i Dedication iii Acknowledgements iv List of Tables vi List of Figures vii List of Abbreviations viii CHAPTER 1: Introduction 1 Life-history Stages and Transitions Synchronization of Seasonal Life-history Stages Sex Differences in Life-history Stage Transitions Neuropeptides as a Mechanism of Behavioral Transitions Study System Questions and Hypotheses CHAPTER 2: Experiment 15 Introduction Materials and Methods Results Discussion CHAPTER 3: Conclusions and Future Directions 56 Seasonal Differences Sex Differences Changes in Migratory Status Changes in Reproductive Status Comparisons between Thamnophis Populations Conclusions References 66
Human Biology of Afro-Caribbean Populations: The Afro-Caribbean population in Limón, Costa Rica

This chapter is the culmination of the entire book, as it will present a microevolutionary history of the Afro-Caribbean population in Limon, Costa Rica. We will start with an historical overview, tying the initial and subsequent migrations which formed this group with the contractions and expansions of the Caribbean economy that were reviewed in Chapter 5. Then we will discuss some of the cultural-anthropological and linguistic work on the group, although this will be by necessity a short section, as this book is about human biology, not cultural anthropology. We will then discuss work on obesity, hypertension, and diabetes in the region, as well as on infectious diseases, and put Limon in the wider Caribbean epidemiologic context. Data are limited for both chronic and infectious diseases unfortunately: in Costa Rica data are collected not according to ethnic group but only to geography. Thus if we work with data from the Limon region we might be looking at data of the Afro-Caribbean and the Hispano-Limonense groups combined. However, a few research projects have focused on the African-derived population, and these will be very helpful. In contrast with epidemiology studies, there are plenty of demographic projects which focus exclusively on the Afro-Limonense population, projects that look at the family structure and other demographic aspects of interest. There have also been more data published on the population genetics of the Afro-Limonense group than on any other Costa Rican group.
Endoplasmic microtubules connect the advancing nucleus to the tip of legume root hairs, but F‐actin is involved in basipetal migration

A prominent feature of tip growth in filamentous plant cells is that the nucleus often migrates in step with the tip as it extends. We have studied this long-recognized but unexplained relationship in root hairs of the legume Vicia hirsuta by a variety of microscopic techniques. Using rhodaminyl lysine phallotoxin, and antitubulin antibodies, root hairs are shown to contain axial bundles of F-actin and a complex microtubular system. To the basal side of the nucleus the microtubules are cortical and net axial but in the region between nucleus and tip the arrangement is more complicated. Electron microscopic thin sections demonstrate that internal bundles of microtubles exist in addition to the plasma membrane-associated kind. Computerized deblurring of through-focal series of antitubulin stained hairs clarifies the three-dimensional organization: bundles of endoplasmic microtubules progress from the nuclear region toward the apical dome where they can be seen to fountain out upon the cortex. The relationship between nucleus and tip can be uncoupled with antimicrotubule herbicides. Time lapse video microscopy shows that these agents cause the nucleus to migrate toward the base. This contrary migration can be inhibited by adding cytochalasin D, which fragments the F-actin bundles. It is concluded that microtubules connect the nucleus to the tip but that F-actin is involved in basipetal migration as is known to occur when symbiotic bacteria uncouple the nucleus from the tip.
ELECTRON MICROSCOPICAL AND IMMUNOLOGICAL OBSERVATIONS ON THE SERUM-HEPATITIS (S.H.) ANTIGEN IN PRIMARY BILIARY CIRRHOSIS

Abstract Particles identical to those associated with S.H. antigen were found by electron microscopy in the sera of 11 out of 12 patients with primary biliary cirrhosis. Antigen and/or antibody to S.H. antigen or antiserum were found in 9 out of 10 cases by immunological methods. It is suggested that immune complexes involving an antigen similar to or identical with S.H. antigen may be present in primary biliary cirrhosis, and that it may be important in the pathogenesis of the disease.
Giving It Away: Sharing and the Future of Scholarly Communication

Debates about open-access scholarly publishing often focus on the costs of scholarship, whether costs incurred by publishers in producing books and journals or costs faced by libraries in acquiring those publications. Taking those costs as the centre of such discussions often results in an impasse, as the financial realities of publishing—particularly within disciplines that are less well-funded than STEM fields (science, technology, engineering and mathematics)—seem to present an insurmountable obstacle to greater openness. What if, however, we were to refocus the discussion on values rather than costs? How might such a shift in focus lead us to think differently about the motives and benefits involved in scholarly communication, and how might this lead us to recognize the generosity that keeps the engine running?
Perceived Teacher Acceptance, Parental Acceptance, and the Adjustment, Achievement, and Behavior of School-Going Youths Internationally

Drawing stimulus from parental acceptance-rejection theory (PARTheory) and associated measures, articles in this special issue attempt to assess the relative contribution of perceived teacher and parental (maternal and paternal) acceptance and behavioral control to the psychological adjustment, school conduct, and academic achievement of school-going youths (boys and girls) within six nations cross-culturally. Results of analyses expose enormous gender and sociocultural variability in the pattern of predictors (i.e., perceived teacher and parental acceptance and behavioral control) associated with each of the three outcome variables studied. This is especially true with respect to predictors of students’ conduct in school and academic achievement. However, as expected from PARTheory, predictors of variations in youths’ psychological adjustment are much more stable: Both perceived teacher acceptance and parental (maternal as well as paternal) acceptance are significantly correlated with the adjustment of b...
The Measure of the Machine: How Exposure to Current Technology Can Upgrade a Student’s Education

Over the past decade there has been a distinct trend toward implementing computer technology in education. The advent of affordable, student accessible computing power has allowed engineering curricula to follow the trends of computer technology in the engineering workplace. The developments in hardware and software, combined with the explosive entrance of the Internet, have allowed design projects to evolve into elaborate and imaginative endeavors. The enhanced speed at which projects can now be completed allows students the opportunity to undertake tasks of greater magnitude, while the advanced tools now available permit students to solve more sophisticated and lifelike problems. The examination of a senior-level design course, in which students must design and build a maze-solving robot, serves to highlight the educational benefits that stand to be gained through the judicious application of technology. The evolutionary history of this design course demonstrates the remarkable progress that computer technology has allowed in educational settings.Copyright © 2004 by ASME
Success as Failure and Failure as Success: The Cultural Literacy of E. D. Hirsch, Jr.

This article examines the logic and rhetoric of E. D. Hirsch, Jr. in Cultural Literacy, attempts to answer the question of how intellectual failure guarantees success in the marketplace, and concludes with an alternative vision of the American society that Hirsch glowingly describes and with the suggestion that Hirsch's cultural literacy is in fact cross-culturalilliteracy. The subsequent publication of the Hirschian Dictionary of Cultural Literacy occasions a postscript that examines the mindset of a comfortable white gerontocracy as it manifests itself in the Dictionary's comic arrogance yet trivial accomplishement.
The effects of compound in vivo and imaginal exposure: A test of fear enhancement models

Eysenck has hypothesized that extinction procedures, such as those used in flooding and implosive therapy, contain implicit aversive reinforcement contingencies which may increase conditioned fear. An alternative view has been proposed by Gordon and his colleagues, who suggest that memory reactivation is responsible for instances of increased fear responding. The present study was designed as a differential test of these proposals. Female students who demonstrated avoidance of a harmless snake were presented with in vivo exposure to the snake in an attempt to replicate previous demonstrations of fear enhancement. Imaginal exposure was added for half of the groups. The primary findings were: (1) a generally linear relationship between the total amount of exposure (whether in vivo and/or imaginal) and improvement in both behavioral approach to the fear stimulus and self-reports of fear; (2) greater physiological improvement associated with combined in vivo and imaginal exposure. Fear enhancement was not replicated and the results were not consistent with Eysenck's incubation model. Instead, the findings support two-factor avoidance theory and are compatible with Gordon's proposal. Additionally, a question is raised regarding the suitability of control procedures in existing between-groups demonstrations of fear enhancement.
Reproductive development and ontogeny of queen pheromone production in the fire ant Solenopsis invicta

Queens of the fire ant, Solenopsis invicta Buren, produce several releaser and primer pheromones. Using bioassays, the ontogeny of three of these pheromones related to reproductive development was investigated. Virgin queens, in which the process of wing-shedding (dealation) serves as an indicator of the initiation of reproductive development, were studied. First, the production of two queen pheromones produced in the poison gland was examined. The pheromone responsible for initiation and maintenance of retinue formation, a releaser effect, was found to be produced in detectable quantities 2 days after dealation, at which time queens showed significant ovary development and many (30%) had started laying eggs. A primer pheromone that inhibits alate virgin queens from dealating was detected in queens 3 days following wing-shedding, when 80% of the queens were ovipositing. Second, I examined the onset of a pheromone of unknown glandular origin produced by reproductively active virgin queens which leads to their destruction in queenright colonies by stimulating workers to attack and kill them. This pheromone is secreted in quantities detectable by bioassay 2 days after dealation. Thus, in S. invicta, the ontogeny of three distinct queen pheromones is tightly linked with ovary development and initiation of egg laying. These results demonstrate reproductive and communicative functions are closely associated during the transition from potential to functional queen.
Science and Cyberinfrastructure: The Chicken and Egg Problem

In September, I participated in a general scientific discussion regarding the U.S. National Science Foundation Directorate for Geosciences (NSF GEO) Priorities and Frontiers 2015–2020 document. One of the key issues raised in conjunction with this document was the issue of science versus infrastructure. Although there was overwhelming agreement on the need for infrastructure to do our science, there was much concern about the corresponding balance of investment.
THE MEGAGAMETOPHYTE OF PINUS. I. INTRODUCTION

The discovery of normal stages in the development of the megagametophyte of Pinus was announced in Science 74: 337-338, I93I. The present outline is an introduction to later publications in which each stage in the development of the gametophyte of Pinus will be described in detail and illustrated with photomicrographs. The megaspore mother cell divides into two daughter cells that differ in size in the proportion of three to four. The smaller daughter cell, which is next to the micropyle, does not divide. The larger daughter cell divides unequally. In this linear row of three cells, the cell at the base serves as the functional megaspore. The remaining two cells decrease in size and finally disappear in two or three weeks' time. The functional megaspore begins a series of free nuclear divisions that occur at regular intervals of about six days. During the six-day interval following the appearance of the megaspore, the cells of the nucellus adjacent to the megaspore are transformed into a nutritive tissue. The nutritive tissue upon digestion provides the food material necessary for the growth of the gametophyte and the continued increase in the number of its nuclei. These nutritive cells, which are tapetal in nature, instead of being limited to one or two rows of cells like the tapetum of microsporangia, digest in a progressive manner all of the nucellus except the nucellar cap through which the pollen tubes are growing. The nucellus is completely digested by the time fertilization occurs in the second year. After a short period of growth, the megaspore nucleus divides into two free nuclei in the center of the ovule. In normal development, the megagametophyte is always in the center of the ovule and expands gradually with the enlargement of the cavity formed by the digestion of the nucellus. Incomplete cell walls may be present in the fourand eight-nuclei stages, but later there are no indications of cell walls. Sixteen and thirty-two nuclei are present at the end of the first month of the growing season. During the second month, 64, I28, and 256 free nuclei appear. The free nuclei are arranged in the form of a tangled network, but their number can be determined by counting all of the nuclei in each series of sections. The first year's growth in Pinus flexrilis and P. scopulorum ends with 5I2 free nuclei. The occurrence of the megagametophyte in the center of the ovule is not
Future Challenges in Single-Molecule Fluorescence and Laser Trap Approaches to Studies of Molecular Motors

Single-molecule analysis is a powerful modern form of biochemistry, in which individual kinetic steps of a catalytic cycle of an enzyme can be explored in exquisite detail. Both single-molecule fluorescence and single-molecule force techniques have been widely used to characterize a number of protein systems. We focus here on molecular motors as a paradigm. We describe two areas where we expect to see exciting developments in the near future: first, characterizing the coupling of force production to chemical and mechanical changes in motors, and second, understanding how multiple motors work together in the environment of the cell.
ISOTHERMAL AND ISOPIESTIC DECOMPOSITION OF POTASSIUM PERCHLORATE AND POTASSIUM CHLORATE

Samples of purified potassium perchlorate were decomposed at various constant pressures of air or oxygen and at various constant temperatures from 555 to 590 deg C. A number of differential thermal analyses of potassium chlorate was made in which the runs were stopped at various temperatures ranging from 330 to about 600 deg C. The purpose of these studies was to establish a record of the thermal behavior throughout the range from room temperature to 600 deg C and to determine the relative amounts of products formed at various stages of decomposition. (W.L.H.)
EFFECTS OF ANISOMYCIN ON RETENTION OF THE PASSIVE-AVOIDANCE HABIT AS A FUNCTION OF AGE

Abstract Three age groups of male Swiss albino CD-1 mice (2-3 mo, 6-7 mo, and 14-15 mo) were treated with a 120 mg/kg dose of the protein synthesis inhibitor anisomycin or with an equal volume of saline at various times before and after training (20 min pretraining, 0, 10, 30, or 180 min posttraining) in a shock motivated passive-avoidance task. Young (2-3 mo) and intermediate-aged (6-7 mo) mice treated with anisomycin before or immediately after training demonstrated impaired retention at a 7 day test, but retention was normal for mice injected 10, 30 or 180 min posttraining. The older mice (14-15 mo) showed similar results, with one exception: those older mice injected with anisomycin 10 min posttraining were significantly impaired in retention as compared to older saline controls and to identically treated young or intermediate-age mice. The prolonged gradient of retrograde amnesia demonstrated by older mice could not be accounted for by impaired acquisition, impaired short-term memory, altered spontan...
Quantifying the effect of wind turbine size and technology on wind power variability

Quantifying wind power variability can be essential to both power system planners and operators, as well as wind farm owners and investors. In this paper the conditional range metric, a novel probabilistic variability metric, is used to quantify wind power variability. The comparison of the wind power variability from four turbines of the same size but different technologies (fixed speed, variable slip, DFIG, full converter) yields that the full converter wind turbine has the least variable and the fixed speed the most variable output, with the fixed speed being 15% more variable than the full converter turbine output. Comparing the output from two variable speed wind turbines of different sizes suggests that wind power variability decreases slightly with turbine size in p.u. values. However, the results of comparing the wind power variability from one turbine at one site to the wind power variability from the aggregated output of two identical turbines at different sites indicate that wind power aggregation provides a significant reduction in wind power variability, since variability increases by no more than 75% regardless of wind turbine size and technology.
Seven new cases of familial isolated bladder exstrophy and epispadias complex (BEEC) and review of the literature

Clustering of the bladder exstrophy and epispadias complex (BEEC) has been described in 29 families. To explore the genetic contribution we located new families through the German and Austrian Bladder Exstrophy Support Group and the Association for the Bladder Exstrophy Community (predominantly US and Canada). We report six new families with two occurrences of BEEC, one family where the proband is the product of a consanguineous union, and four discordant twin pairs. In conjunction with the published clinical and epidemiological reports this collection suggests that there is a significant genetic predisposition for susceptibility to the BEEC. It also highlights the importance of self-referral groups for recruiting families for multicenter collaborative research efforts to identify susceptibility loci.
Time-resolved photothermal deflection measurements of thermophysical properties of solid materials with step optical excitation

Thermal properties of solid samples have been measured using recently developed time-resolved photothermal deflection spectrometry with step optical excitation. Thermal diffusivity can be measured directly, and thermal effusivity may be obtained by using a reference sample. Consequently, the thermal conductivity and the unit volume specific heat of a sample can be deduced from the measured thermal diffusivity and effusivity. The experimental results are in good agreement with literature values, indicating the time-resolved photothermal deflection spectrometry with step optical excitation is a very rigorous method in measuring thermophysical properties of solid materials.
Aerosol generation from a limited liquid medium.

A modified method for nebulization was developed for use with relatively small (20 mL) amounts of feed liquid, in this case, a suspension of radioactively tagged polystyrene (CMD = 2.87 µm, σ g = 1.25). The method may be easily adapted for use in producing other aerosols where only this quantity of suspension material is available.