cssi/SciSciGPT-SciSciNet huggingface dataset:
Towards Automatic Evaluation of Dialog Systems: A Model-Free Off-Policy Evaluation Approach

Reliable automatic evaluation of dialogue systems under an interactive environment has long been overdue. An ideal environment for evaluating dialog systems, also known as the Turing test, needs to involve human interaction, which is usually not affordable for large-scale experiments. Though researchers have attempted to use metrics for language generation tasks (e.g., perplexity, BLEU) or some model-based reinforcement learning methods (e.g., self-play evaluation) for automatic evaluation, these methods only show very weak correlation with the actual human evaluation in practice. To bridge such a gap, we propose a new framework named ENIGMA for estimating human evaluation scores based on recent advances of off-policy evaluation in reinforcement learning. ENIGMA only requires a handful of pre-collected experience data, and therefore does not involve human interaction with the target policy during the evaluation, making automatic evaluations feasible. More importantly, ENIGMA is model-free and agnostic to the behavior policies for collecting the experience data, which significantly alleviates the technical difficulties of modeling complex dialogue environments and human behaviors. Our experiments show that ENIGMA significantly outperforms existing methods in terms of correlation with human evaluation scores.
Stochastic Optimization for Vaccine and Testing Kit Allocation for the COVID-19 Pandemic.

We present a formal mathematical modeling framework for a multi-agent sequential decision problem during an epidemic. The problem is formulated as a collaboration between a vaccination agent and learning agent to allocate stockpiles of vaccines and tests to a set of zones under various types of uncertainty. The model is able to capture passive information processes and maintain beliefs over the uncertain state of the world. We designed a parameterized direct lookahead approximation which is robust and scalable under different scenarios, resource scarcity, and beliefs about the environment. We design a test allocation policy designed to capture the value of information and demonstrate that it outperforms other learning policies when there is an extreme shortage of resources (information is scarce). We simulate the model with two scenarios including a resource allocation problem to each state in the United States and another for the nursing homes in Nevada. The US example demonstrates the scalability of the model and the nursing home example demonstrates the robustness under extreme resource shortages.
High variability in transmission of SARS-CoV-2 within households and implications for control.

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a high risk of transmission in close-contact indoor settings, which may include households. Prior studies have found a wide range of household secondary attack rates and may contain biases due to simplifying assumptions about transmission variability and test accuracy. Methods We compiled serological SARS-CoV-2 antibody test data and prior SARS-CoV-2 test reporting from members of 9,224 Utah households. We paired these data with a probabilistic model of household importation and transmission. We calculated a maximum likelihood estimate of the importation probability, mean and variability of household transmission probability, and sensitivity and specificity of test data. Given our household transmission estimates, we estimated the threshold of non-household transmission required for epidemic growth in the population. Results We estimated that individuals in our study households had a 0.41% (95% CI 0.32%- 0.51%) chance of acquiring SARS-CoV-2 infection outside their household. Our household secondary attack rate estimate was 36% (27%- 48%), substantially higher than the crude estimate of 16% unadjusted for imperfect serological test specificity and other factors. We found evidence for high variability in individual transmissibility, with higher probability of no transmissions or many transmissions compared to standard models. With household transmission at our estimates, the average number of non-household transmissions per case must be kept below 0.41 (0.33-0.52) to avoid continued growth of the pandemic in Utah. Conclusions Our findings suggest that crude estimates of household secondary attack rate based on serology data without accounting for false positive tests may underestimate the true average transmissibility, even when test specificity is high. Our finding of potential high variability (overdispersion) in transmissibility of infected individuals is consistent with characterizing SARS-CoV-2 transmission being largely driven by superspreading from a minority of infected individuals. Mitigation efforts targeting large households and other locations where many people congregate indoors might curb continued spread of the virus.
Multi-Server Private Linear Transformation with Joint Privacy

This paper focuses on the Private Linear Transformation (PLT) problem in the multi-server scenario. In this problem, there are N servers, each of which stores an identical copy of a database consisting of K independent messages, and there is a user who wishes to compute L independent linear combinations of a subset of D messages in the database while leaking no information to the servers about the identity of the entire set of these D messages required for the computation. We focus on the setting in which the coefficient matrix of the desired L linear combinations generates a Maximum Distance Separable (MDS) code. We characterize the capacity of the PLT problem, defined as the supremum of all achievable download rates, for all parameters N, K, D ≥ 1 and L = 1, i.e., when the user wishes to compute one linear combination of D messages. We show that the capacity in this case is Φ(1/N, K − D + 1), where Φ(A, B) ≜ (1 + A + A2 + ⋯ + AB−1)−1. Moreover, we establish an upper bound and lower bounds on the capacity of the PLT problem for all parameters N, K, D, L ≥ 1. We show that for the regime where K − D is a non-negative integer multiple of L, the proposed capacity upper bound is equal to Φ(1/N, (K −D +L)/L). Also, leveraging some known capacity results, we show the tightness of this bound in the following regimes: (i) the case when there is a single server (i.e., N = 1), (ii) the case when L = 1, and (iii) the case when L = D.
When Moving‐Average Models Meet High‐Frequency Data: Uniform Inference on Volatility

We conduct inference on volatility with noisy high‐frequency data. We assume the observed transaction price follows a continuous‐time Ito‐semimartingale, contaminated by a discrete‐time moving‐average noise process associated with the arrival of trades. We estimate volatility, defined as the quadratic variation of the semimartingale, by maximizing the likelihood of a misspecified moving‐average model, with its order selected based on an information criterion. Our inference is uniformly valid over a large class of noise processes whose magnitude and dependence structure vary with sample size. We show that the convergence rate of our estimator dominates n1/4 as noise vanishes, and is determined by the selected order of noise dependence when noise is sufficiently small. Our implementation guarantees positive estimates in finite samples.
Emergent Communication of Generalizations

To build agents that can collaborate effectively with others, recent research has trained artificial agents to communicate with each other in Lewis-style referential games. However, this often leads to successful but uninterpretable communication. We argue that this is due to the game objective: communicating about a single object in a shared visual context is prone to overfitting and does not encourage language useful beyond concrete reference. In contrast, human language conveys a rich variety of abstract ideas. To promote such skills, we propose games that require communicating generalizations over sets of objects representing abstract visual concepts, optionally with separate contexts for each agent. We find that these games greatly improve systematicity and interpretability of the learned languages, according to several metrics in the literature. Finally, we propose a method for identifying logical operations embedded in the emergent languages by learning an approximate compositional reconstruction of the language.
DiffPD: Differentiable Projective Dynamics

We present a novel, fast differentiable simulator for soft-body learning and control applications. Existing differentiable soft-body simulators can be classified into two categories based on their time integration methods: Simulators using explicit time-stepping scheme require tiny time steps to avoid numerical instabilities in gradient computation, and simulators using implicit time integration typically compute gradients by employing the adjoint method and solving the expensive linearized dynamics. Inspired by Projective Dynamics (PD), we present Differentiable Projective Dynamics (DiffPD), an efficient differentiable soft-body simulator based on PD with implicit time integration. The key idea in DiffPD is to speed up backpropagation by exploiting the prefactorized Cholesky decomposition in forward PD simulation. In terms of contact handling, DiffPD supports two types of contacts: a penalty-based model describing contact and friction forces and a complementarity-based model enforcing non-penetration conditions and static friction. We evaluate the performance of DiffPD and observe it is 4-19 times faster compared to the standard Newton's method in various applications including system identification, inverse design problems, trajectory optimization, and closed-loop control. We also apply DiffPD in a real-to-sim example with contact and collisions and show its capability of reconstructing a digital twin of real-world scenes.
Fairness in machine learning: against false positive rate equality as a measure of fairness

As machine learning informs increasingly consequential decisions, different metrics have been proposed for measuring algorithmic bias or unfairness. Two popular fairness measures are calibration and equality of false positive rate. Each measure seems intuitively important, but notably, it is usually impossible to satisfy both measures. For this reason, a large literature in machine learning speaks of a fairness tradeoff between these two measures. This framing assumes that both measures are, in fact, capturing something important. To date, philosophers have not examined this crucial assumption, and examined to what extent each measure actually tracks a normatively important property. This makes this inevitable statistical conflict, between calibration and false positive rate equality, an important topic for ethics. In this paper, I give an ethical framework for thinking about these measures and argue that, contrary to initial appearances, false positive rate equality does not track anything about fairness, and thus sets an incoherent standard for evaluating the fairness of algorithms.
Columnar processing of border ownership in primate visual cortex

To understand a visual scene, the brain needs to identify objects and distinguish them from background. A border marks the transition from object to background, but to differentiate which side of the border belongs to the object and which to background, the brain must integrate information across space. An early signature of this computation is that brain cells signal which side of a border is ‘owned’ by an object, also known as border ownership. But how the brain computes border ownership remains unknown. The optic nerve is a cable-like group of nerve cells that transmits information from the eye to the brain’s visual processing areas and into the visual cortex. This flow of information is often described as traveling in a feedforward direction, away from the eyes to progressively more specialized areas in the visual cortex. However, there are also numerous feedback connections in the brain, running backward from more specialized to less specialized cortical areas. To better understand the role of these feedforward and feedback circuits in the visual processing of object borders, Franken and Reynolds made use of their stereotyped projection patterns across the cortex layers. Feedforward connections terminate in the middle layers of a cortical area, whereas feedback connections terminate in upper and lower layers. Since time is required for information to traverse the cortical layers, dissecting the timing of border ownership signals may reveal if border ownership is computed in a feedforward or feedback manner. To find out more, electrodes were used to record neural activity in the upper, middle and lower layers of the visual cortex of two rhesus monkeys as they were presented with a set of abstract scenes composed of simple shapes on a background. This revealed that cells signaling border ownership in deep layers of the cortex did so before the signals appeared in the middle layer. This suggests that feedback rather than feedforward is required to compute border ownership. Moreover, Franken and Reynolds found evidence that cells that prefer the same side of border ownership are clustered in columns, showing how these neural circuits are organized within the visual cortex. In summary, Franken and Reynolds found that the circuits of the primate brain that compute border ownership occur as columns, in which cells in deep layers signal border ownership first, suggesting that border ownership relies on feedback from more specialized areas. A better understanding of how feedback in the brain works to process visual information helps us appreciate what happens when these systems are impaired.
Employment Status as a Basis of Segmentation of Female Consumers' Adaptive Shopping Behavior

The objective of this research study is to assess the effectiveness of employment status of female head of household for segmenting markets for non-durable goods. Results indicate that employment status correlates with adaptive shopping behaviors of female shoppers.
Memory, Electronic—Chronology to 1990

Historical Perspective Read-Only Memories (ROMs) The Groundwork for Creating the Electronic Memories of the 1990s Transferring Data between Functional Modules Keywords: memory, electronic—chronology to 1990
Practical computation of the mixed μ problem

Upper and lower bounds for the mixed μ problem have recently been developed, and this paper examines the computational aspects of these bounds. In particular a practical algorithm is developed to compute the bounds. This has been implemented as a Matlab function (m-file), and will be available shortly in a test version in conjunction with the μ-Tools toolbox. The algorithm performance is very encouraging, both in terms of accuracy of the resulting bounds, and growth rate in required computation with problem size. In particular it appears that one can handle medium size problems (less than 100 perturbations) with reasonable computational requirements.
Average Reward of a Given MDP Policy

This article describes the fundamentals of determining the average reward of a given policy for a Markov decision process (MDP). For an MDP, a given policy induces a DTMC with rewards. The average reward for the policy is then dependent on the structure of this induced Markov chain. Summarized within this article are the classifications of average reward MDPs, the definition of the gain and bias for a given MDP policy, and approaches for determining the gain and bias for each of these classifications. Keywords: Markov decision process; MDP; DTMC; average reward; stationary Markov deterministic policy
Facial Attractiveness and Helping Behavior Beliefs Both Attractive and Unattractive Targets Are Believed to Be Unhelpful Relative to Moderately Attractive Targets

On a between-subjects (Experiment 1A) and within-subjects (Experiment 1B) basis, participants indicated a belief that attractive and unattractive targets engage in less actual helping behavior than moderately attractive targets. In Experiment 2, attractive and moderately attractive targets were seen as more capable of helping than unattractive targets; attractive and unattractive targets were seen as less willing to help than moderately attractive targets. Multilevel modeling indicated that perceptions of helping capability and willingness mediated perceptions of how much targets actually help and should help. Whereas unattractive targets are seen as unhelpful due to both a lack of ability and motivation to help (negativity halo), attractive targets are also seen as unhelpful, but due uniquely to a perceived unwillingness to help.
A Proof-of-Concept Case Study for Personalized Noninvasive Prenatal Diagnosis: Can We Put It to Work?

This commentary highlights the article by van den Oever et al that describes a new method of prenatal diagnosis of single-mutation disorders.
On the mechanism and branching ratio of the cyanogen + oxygen .fwdarw. carbon monoxide + nitric oxide reaction channel using transient IR emission spectroscopy

The contribution of the title reaction to the total reaction of CN+O 2 has been determined, using time-resolved IR emission spectroscopy of the product CO(υ''). This product channel is found to contribute up to 29% with 2% experimental variance to the total reaction. A contribution of this magnitude to the total reaction of CN+O 2 by this product channel proceeding via a four-center transition state is energetically improbable. Ab initio calculations have been performed on two- and four-center transition states which are presumably formed in the reaction between CN radicals and molecular oxygen. The results of these calculations confirm the existence of a very high barrier to the formation of a four-center transition state. Consequently, a new mechanism for the formation of CO in reaction 1 is proposed
Evaluating the thermal damage resistance of graphene/carbon nanotube hybrid composite coatings

We study laser irradiation behavior of multiwalled carbon nanotubes (MWCNT) and chemically modified graphene (rGO)-composite spray coatings for use as a thermal absorber material for high-power laser calorimeters. Spray coatings on aluminum test coupon were exposed to increasing laser irradiance for extended exposure times to quantify their damage threshold and optical absorbance. The coatings, prepared at varying mass % of MWCNTs in rGO, demonstrated significantly higher damage threshold values at 2.5 kW laser power at 10.6 μm wavelength than carbon paint or MWCNTs alone. Electron microscopy and Raman spectroscopy of irradiated specimens show that the coating prepared at 50% CNT loading endure at least 2 kW.cm−2 for 10 seconds without significant damage. The improved damage resistance is attributed to the unique structure of the composite in which the MWCNTs act as an efficient absorber of laser light while the much larger rGO sheets surrounding them, dissipate the heat over a wider area.
Treading with care: foot care, litigation and the expert witness

This is a practical introduction to acting as an expert witness. The expert's report is an integral part of all litigation concerning allegations of professional negligence. A well-written report, embodying principles of sound academic research, is less likely to be challenged in court than a badly-prepared one. An expert should not hesitate to question his terms of reference if they are unclear or require widening. It is crucial to remember that the report is written for the benefit of the court, not the instructing party. In the witness box, the oath to tell the truth, the whole truth and nothing but the truth is paramount. It should be assumed that the Judge can grasp difficult medical concepts but may require fuller explanation than a fellow medical practitioner. It is important to answer the question that has been asked – but it is in order to disagree with a false premise. Appropriate concessions are more likely to impress the court than posturing. Each question should be treated on its merits. In conclusion, the role of the expert witness is demanding but application of these principles should make it a less daunting experience. Copyright © 2004 John Wiley & Sons, Ltd.
Lipid peroxidation in fish muscle microsomes in the frozen state.

Abstract The microsomal fraction from fish muscle has previously been shown to catalyze the oxidation of its lipid. In this study we have studied the rate of the reaction in the frozen state. The rate was dependent on temperature, decreasing with decreasing temperature. When the microsomes were frozen in the presence of NaCl there was greater activity than when they were frozen in the presence of KCl. The specific activity of the oxidation decreased with increasing protein concentration. This is possibly due to the limitation of oxygen in the frozen system. Lipid oxidation is a complex reaction and both initial products (lipid hydroperoxides) and breakdown products (those reacting with malondialdehyde) were measured. This ratio was relatively constant over a variety of conditions indicating that the rate-limiting step of the reaction occurred prior to the formation of lipid hydroperoxide. A study of the reaction at above-freezing temperatures and below-freezing temperatures in the presence of miscible solvents to prevent freezing at temperatures below 0 °C gave results which were consistent with the hypothesis that ice crystal formation had an accelerating effect on the reaction. Presumably this is due to concentration of reactants since freezing and thawing of the microsomes did not affect their rates of lipid oxidation. Potent inhibitors of the lipid oxidation reaction were found in the soluble fraction of the muscle tissue. These were both high-molecular and low-molecular-weight compounds. The low-molecular-weight inhibitors were more effective in the frozen state while the high-molecular-weight compounds were relatively more effective in the reaction catalyzed at temperatures above freezing.
Age-related Fatigue Resistance in the Knee Extensor Muscles Is Specific to Contraction Mode

The question of whether skeletal muscle fatigue is preserved or enhanced in older adults is a point of controversy. Disparate findings may be attributed to differences in subject population and study protocols, including contraction mode. The purpose of this study was to test the hypotheses that healthy older (65–80 years, n = 8M, 8F) adults who were matched to young adults (21–35; 8M, 8F) with similar physical activity levels would: 1) fatigue less during isometric knee extensor (KE) contractions, but 2) would show similar fatigue during dynamic KE contractions performed at 120 deg·s−1. Fatigue was induced with 4 min of intermittent, isometric or dynamic maximal voluntary contractions, performed on separate days. Electrically-stimulated contractions were used to evaluate central activation during both fatigue protocols. Older subjects maintained a higher percentage of baseline MVC torque than young subjects during isometric contractions (mean±SE of 71±3% and 57±3%, respectively, p<0.01). In contrast, there was no difference between age groups in torque maintenance during dynamic contractions (43±3% and 44±3%, respectively, p=0.86). For both groups, changes in electrically-stimulated and voluntary contractions followed similar trends, suggesting that central activation did not play a role in the age-related differences in fatigue. Fatigue during the isometric protocol was associated with fatigue during the dynamic protocol in the young group only (r=0.62, p=0.01), suggesting that distinct mechanisms influence fatigue during isometric and dynamic contractions in older adults.
Effects of some geometric variations on missile aerodynamic characteristics at supersonic speeds

A summary of some results from tests of a wing-body general research missile model is presented for a Mach number range up to 4.63. A basic ogive-cylinder body with a length-to-diameter ratio of 10 was used to which was attached a series of wing planforms. The planforms included a family of delta wings and a family of rectangular wings having a constant root chord but varying spans so that wings of constant exposed area could be compared. In addition, a cranked-tip planform was included and a rectangular planform with reduced chord. Some results are presented for wing-body-tail configurations - one utilizing a cranked wing planform and one with wings having a constant root chord and span, but tip chords that were 0, 20, and 40 percent of the root chord.
Hard magnetic FePt nanoparticles by salt-matrix annealing

Proceedings of the 50th Annual Conference on Magentism and Magnetic Materials. L10 and Other Hard Magnetic Materials L10 and Other Hard Magnetic Materials L10 and Other Hard Magnetic Materials. L10 and Other Hard Magnetic Materials.
Nutrient Intakes and Serum Antioxidant Nutrient Levels Among American Smokers Aged 17–50 Years from Nhanes III

Abstract Data of 7,873(3,972 men and 3,901 women) apparently healthy adults aged 17–50 years from NHANES III were analyzed to compare the nutrient intakes and the serum antioxidant-nutrient levels between smokers and nonsmokers. Subjects were grouped as nonsmokers or smokers if their serum cotinine levels were = 14 ng/ml. SUDAAN statistical software program was used for the multiple regression analysis. Smoking prevalence was 40.17 and 29.72% among men and women, respectively. Men smokers had significantly lower intakes of carbohydrate, vitamin A,D,E,CJB 1 ,B2,B6,β-carotene, folate, pantothenic acid, Ca,P,Mg and Fe, but higher intake of saturated fatty acid than nonsmokers. Likewise, women smokers had significantly lower intakes of vitamin A,C,B 1,B6, β-carotene, folate, pantothenic acid and Fe than nonsmokers. Serum levels of antioxidants were adjusted with the respective intakes to study the association of smoking. Men smokers had significantly (p
Diuretic effects on renal brush border membrane transport and metabolism

Previous studies have indicated that the thiazide diuretics exert effects on proximal electrolyte transport. To determine whether the locus of these effects is at the brush border membrane (BBM) and if renal metabolism is affected, adult female Sprague-Dawley rats were acutely treated with either 1 mg/kg metolazone, 20 mg/kg chlorothiazide followed by a 20 mg/kg/hr maintenance infusion, 10 mg/kg acetazolamide followed by a 10 mg/kg/hr maintenance infusion, or the vehicles only. Administration of these agents resulted in an approximately tenfold increase in sodium excretion. Neither urinary phosphate nor inulin excretion changed significantly in any group. Sodium dependent BBM vesicle phosphate transport was examined at 0.15, 0.5, and 1 and 120 minute incubation periods in the diuretic treated groups and their respective control groups. Decreased uptake was seen in all pre-equilibrium time points in rats treated with metolazone: 0.15 minutes: 221 +/- 24 pmoles/mg protein (pmol/mg prot) in control rats versus (vs) 185 +/- 23 pmoles/mg prot in metolazone-treated animals (P less than .05) ; 0.5 minutes: 463 +/- 54 vs 369 +/- 49 pmol/mg prot (P less than .005); 1 minute: 549 +/- 74 vs 460 +/- 61 pmol/mg prot (P less than .05); no significant difference in phosphate transport was noted at the two hour equilibrium time point. No significant differences in sodium dependent phosphate transport existed between chlorothiazide or acetazolamide treated rats and control animals. Substrate-stimulated renal gluconeogenesis did not differ between metolazone treated and control animals. We therefore conclude that metolazone inhibits phosphate transport through an effect on the BBM and does not affect renal gluconeogenesis in the rat.
The education potential of the pharmacogenetics and pharmacogenomics knowledge base (PharmGKB)

The pharmacogenetics and pharmacogenomics knowledge base (PharmGKB, http://www.pharmgkb.org) is a publicly available internet resource dedicated to the integration, annotation, and aggregation of pharmacogenomic knowledge. PharmGKB is a repository for pharmacogenetic and pharmacogenomic data, and curators provide integrated knowledge in terms of gene summaries, pathways, and annotated literature. Although PharmGKB is primarily directed toward catalyzing new research, it also has utility as a source of information for education about pharmacogenomics.
Resistance of Bovine Spongiform Encephalopathy (BSE) Prions to Inactivation

Distinct prion strains often exhibit different incubation periods and patterns of neuropathological lesions. Strain characteristics are generally retained upon intraspecies transmission, but may change on transmission to another species. We investigated the inactivation of two related prions strains: BSE prions from cattle and mouse-passaged BSE prions, termed 301V. Inactivation was manipulated by exposure to sodium dodecyl sulfate (SDS), variations in pH, and different temperatures. Infectivity was measured using transgenic mouse lines that are highly susceptible to either BSE or 301V prions. Bioassays demonstrated that BSE prions are up to 1,000-fold more resistant to inactivation than 301V prions while Western immunoblotting showed that short acidic SDS treatments reduced protease-resistant PrPSc from BSE prions and 301V prions at similar rates. Our findings argue that despite being derived from BSE prions, mouse 301V prions are not necessarily a reliable model for cattle BSE prions. Extending these comparisons to human sporadic Creutzfeldt-Jakob disease and hamster Sc237 prions, we found that BSE prions were 10- and 106-fold more resistant to inactivation, respectively. Our studies contend that any prion inactivation procedures must be validated by bioassay against the prion strain for which they are intended to be used.
A Kinetic-Model for Sulfur Accelerated Vulcanization of a Natural-Rubber Compound

Vulcanization kinetics for a natural rubber compound were studied by a kinetic approach using the cure meter and DSC methods. A simplified but realistic model reaction scheme was used to simulate induction, curing, and overcure periods continuously. Physically significant parameters of the model were extracted from isothermal experimental data using a cure meter. The calculation demonstrated a good correspondence with isothermal cure meter data over the temperature range studied. The length of induction time, variation of maximum modulus with temperature, and the reversion phenomena observed from cure curves can be predicted. DSC data were found to be incompatible with the cure meter test, because the complex vulcanization reaction system is multiexothermal and it is difficult to isolate the heat due to crosslinking. Hence, the cure meter technique is suggested for the study of crosslink formation. The kinetic approach provides a way to incorporate vulcanization kinetics into simulation of reactive processing operations. © 1996 John Wiley & Sons, Inc.
Juggling land retirement objectives on an agricultural landscape: coordination, conflict, or compromise?

Strategic land retirement in agricultural settings has been used as one way to achieve a combination of social objectives, which include ameliorating water quality problems and enhancing existing systems of wildlife habitat. This study uses a simulation model operating on a virtual landscape, along with the compromise programming method, to illustrate the implications of alternative weighting schemes for the long-term performance of the landscape toward various objectives. The analysis suggests that particular spatial patterns may be related to how various objectives are weighted. The analysis also illustrates the inevitable trade-offs among objectives, although it may be tempting to present retirement strategies as “win-win.”
3,7-Dimethyl-1-propargylxanthine: A potent and selective in vivo antagonist of adenosine analogs

Abstract 3,7-Dimethyl-1-propargylxanthine (DMPX), a caffeine analog that exhibits in vitro selectivity for A2-adenosine receptors, compared to A1-adenosine receptors, has now been investigated with respect to in vivo potency and selectivity. DMPX potently and selectively blocked the actions of the potent A2 adenosine agonist, 5′-N-ethylcarboxamidoadenosine (NECA), in DBA/2 mice, compared to blockade of the same responses elicited by the selective A1-adenosine agonist, N6-cyclohexyladenosine (CHA). DMPX was 57-fold more potent versus NECA-induced hypothermia than versus CHA-induced hypothermia and 11-fold more potent versus NECA-induced behavioral depression than versus CHA-induced behavioral depression. The hypothermia is mediated by peripheral receptors, based on blockade by 8-(p-sulfophenyl)theophylline (PSPT), while the behavioral depression is centrally mediated, based on lack of blockade by PSPT. DMPX was 28- and 15-fold more potent than caffeine in blocking peripheral and central NECA-responses, respectively. DMPX was equipotent with caffeine versus CHA-induced hypothermia and 2.5-fold more potent than caffeine versus CHA-induced behavioral depression. The motor stimulating potency of DMPX (ED50 10 μmol/kg) was slightly greater than caffeine.
Marginal stability boundaries for some driven, damped, non-linear oscillators

Abstract A procedure is developed for averaging the differential equations for certain non-linear oscillators which are damped and externally driven. The procedure makes possible the obtaining of marginal stability boundaries for bifurcations in parameter space and is useful for systems with unperturbed solutions involving Jacobi elliptic functions. Specific cases of a driven, damped pendulum, an anharmonie oscillator, a Duffing oscillator, and a non-linear Helmholtz oscillator are examined.
Obtaining Respondent Cooperation in Family Panel Studies

Problems of maintaining respondent rapport in surveys are exacerbated when respondents are asked to participate repeatedly over time or when several members of a family are interviewed. This article details the techniques used to maintain respondent rapport in a longitudinal study involving six interviews over eighteen years, which, after being expanded to include a second family member, still included 85% of the original respondents. The article describes techniques designed to assist and motivate the interviewers to do an effective job and those utilized to make the interviewing process pleasant and rewarding for the respondents.
On Digital Consciousness and Psychic Death

This paper describes states of consciousness in some disturbed or traumatized patients in which time is not experienced as being linked to future or past. The patient's experience in this state is “digital” rather than continuous, making it difficult for him to have an inner sense of continual “aliveness” and to link analytic sessions together. In extreme cases, his world may be experienced as a succession of moments interrupted by little blanks or psychic deaths. The experiential, developmental, and neurobiological aspects of these states are explored with an emphasis on implications for psychoanalytic treatment.
Isothermal viscoelastic properties of PMMA and LDPE over 11 decades of frequency and time: a test of time–temperature superposition

Many instruments used to measure viscoelastic properties are only capable of subjecting a sample to a limited range of loading frequencies. For thermorheologically simple materials, it is assumed that a change in temperature is equivalent to a shift of the viscoelastic behavior on the log frequency or time axis. For many materials, time–temperature superposition appears to work well for modulus or compliance curves over three decades of time or frequency, but some deviations are known if the window is expanded to five or six decades. To apply a more stringent test of the validity of time–temperature superposition, broadband viscoelastic spectroscopy is used to isothermally study polymethylmethacrylate and low-density polyethylene at several temperatures in the glassy region. Shear modulus and damping (tan δ) are measured isothermally over a wide range (up to 11 decades) of time and frequency. Results indicate that, while modulus curves can be approximately superimposed, the damping (tan δ) curves change in height and shape with temperature.
FabH Mutations Confer Resistance to FabF-Directed Antibiotics in Staphylococcus aureus

Delineating the mechanisms for genetically acquired antibiotic resistance is a robust approach to target validation and anticipates the evolution of clinical drug resistance. This study defines a spectrum of mutations in fabH that render Staphylococcus aureus resistant to multiple natural products known to inhibit the elongation condensing enzyme (FabF) of bacterial type II fatty acid synthesis. Twenty independently isolated clones resistant to platensimycin, platencin, or thiolactomycin were isolated. All mutants selected against one antibiotic were cross-resistant to the other two antibiotics. Mutations were not detected in fabF, but the resistant strains harbored missense mutations in fabH. The altered amino acids clustered in and around the FabH active-site tunnel. The mutant FabH proteins were catalytically compromised based on the low activities of the purified enzymes, a fatty acid-dependent growth phenotype, and elevated expression of the fabHF operon in the mutant strains. Independent manipulation of fabF and fabH expression levels showed that the FabH/FabF activity ratio was a major determinant of antibiotic sensitivity. Missense mutations that reduce FabH activity are sufficient to confer resistance to multiple antibiotics that bind to the FabF acyl-enzyme intermediate in S. aureus.
The effect of penetrating agents and pH modification on the permeability of a loam soil to water

Abstract Five commercially available penetrating agents and sulfuric acid were tested for their ability to facilitate water penetration in soil using soil column and/or field experiments. Only one of these, “Charge”;, increased water penetration in soil column tests; all five compounds were ineffective under field conditions. While initial treatment with sulfuric acid resulted in slower penetration, periodic rewetting of treated soil indicated that water penetration was significantly enhanced.
Compatibility and commutativity of lock modes

An important characteristic of concurrency control mechanisms is the level of concurrency that they support. In this paper, we study this problem in the context of non-two-phase locking protocols which are defined for data bases in which a directed acyclic graph structure is superimposed on the data items. A new lock mode is introduced called INV, with properties fundamentally different from lock modes previously studied and show how this allows increased concurrency. Through the introduction of the INV mode of locking, a new principle of the theory of data base concurrency control is enunciated. This principle involves the separation of the effects of commutativity (which relates to serializability) and compatibility (which relates to deadlock-freedom of data manipulation operations. It is shown how the level of concurrency in an existing very general protocol could be increased. Then how the extension affects the occurrence of deadlocks is examined. Certain conditions under which deadlock-freedom is maintained are identified, and simple methods for removing deadlocks in other situations are presented.
Increased myofilament Ca2+-sensitivity and arrhythmia susceptibility.

Abstract Increased myofilament Ca2+ sensitivity is a common attribute of many inherited and acquired cardiomyopathies that are associated with cardiac arrhythmias. Accumulating evidence supports the concept that increased myofilament Ca2+ sensitivity is an independent risk factor for arrhythmias. This review describes and discusses potential underlying molecular and cellular mechanisms how myofilament Ca2+ sensitivity affects cardiac excitation and leads to the generation of arrhythmias. Emphasized are downstream effects of increased myofilament Ca2+ sensitivity: altered Ca2+ buffering/handling, impaired energy metabolism and increased mechanical stretch, and how they may contribute to arrhythmogenesis.
Iterative EM channel estimation for turbo-coded DS-CDMA receiver under time-varying interference

This paper proposes a scheme of iteratively obtaining an estimate of channel coefficients and noise power spectral density (PSD) using expectation maximization (EM) for turbo-coded code-division multiple access receivers. The EM channel estimation is tested under two scenarios - time-varying interference environment with pilot symbol-aided modulation, and a single-user environment without any pilot symbols. For the time-varying interference scenario, the initial estimate of channel coefficient and the noise PSD are obtained from pilots and further estimations are refined using turbo decoder soft outputs. In contrast, pilot symbols are eliminated for the single-user iterative receiver with initial estimation performed from the received code symbols, followed by the iterative updates using the feedback from the turbo decoder as before. The refined channel coefficients and noise PSD are iteratively passed to the turbo decoder resulting in improved decoding results for both time-varying interference and single-user scenarios.
Systematic occurrence of repeated eigenvalues in structural optimization

Examples of finite-dimensional structural design problems with constraints on natural frequency and buckling are used to demonstrate that repeated eigenvalues may be expected to occur when a structure is optimized. It is shown that a repeated eigenvalue is not generally differentiable with respect to design variables. Directional derivatives are shown to exist, and a method of calculating directional derivatives is given. Necessary conditions of optimality are derived and applied to a vibration optimization problem. Extensions of the theory to distributed-parameter structures and numerical methods are outlined.
The use of gene expression profiling to dissect the stress sensitivity of reproductive development in maize

Abstract With the advent of large-scale genomic sequencing, complete or partial genomic sequencing has been conducted on a range of species resulting in a significant increase in gene sequence information. Although the number of genes identified is increasing, our knowledge of the function and interaction of these newly discovered genes is lacking. Functional genomic tools have been developed to improve our understanding of these genes. Gene expression profiling, also known as transcript profiling or mRNA profiling, is one such tool and its use is the focus of this paper. We utilized two unique gene expression profiling technologies, the molecular dynamic (MD)/Amersham microarray and the Affymetrix GeneChip, to investigate the effect of abiotic stress on gene expression in female reproductive tissues of maize (Zea mays L.). The MD microarray, described here as a targeted genomic approach, was populated with 384 maize genes largely comprising four important metabolic pathways with rigorous gene coverage within each pathway. In contrast, the Affymetrix GeneChip, defined here as a non-targeted genomic approach, was designed to provide a survey of metabolism, spanning 27 pathways, including >300 unknown genes. We utilized these technologies in conjunction with traditional physiological approaches to sample tissues subjected to various forms of abiotic stress. From these experiments, we conclude that flowering remains a susceptible developmental period to abiotic stress in elite maize hybrids and yield losses are associated with abnormal floral development and impaired ear growth. With the targeted approach, we show that genes within the starch biosynthetic pathway are coordinately regulated under stress and the decrease in expression of these genes co-varies with the loss of starch. The non-targeted approach: (1) revealed a set of genes that were consistently affected by abiotic stress regardless of tissue type; (2) demonstrated that gene expression in some tissues is more responsive to stress than other tissues; (3) identified a group of genes that were drought responsive that would not have been predicted a priori. Collectively, these experiments provide examples of how these technologies can be used for both gene and pathway discovery.
Medical ethics education: Coming of age.

Medical ethics education is instruction that endeavors to teach the examination of the role of values in the doctor's relationship with patients, colleagues, and society. It is one front of a broad curricular effort to develop physicians' values, social perspectives, and interpersonal skills for the practice of medicine. The authors define medical ethics education as more clinically centered than human values education and more inclusive of philosophical, social, and legal issues than is interpersonal skills training. The authors review the history of the emergence of medical ethics education over the last 20 years, examine the areas of consensus that have emerged concerning the general objectives and premises for designing medical ethics programs, and describe teaching objectives and methods, course content, and program evaluation used in such programs on both preclinical and clinical levels. The four interrelated requirements for successful institutionalization of medical ethics education programs are defined and discussed, and the paper ends with an overview of the uncertain future of medical ethics education, an accepted but still not fully mature part of physician training in the United States. An extensive reference list accompanies the article.
Long-term suppression of the cerebral spread of a memory: effects of idazoxan and clonidine.

Abstract Bitemporal injections of puromycin consistently induce amnesia of aversive maze-learning in mice when administered within 3 days of training. These bitemporal puromycin injections lose their amnestic effectiveness if the latency between training and injection is extended beyond 6 days. Consistent with other evidence, we believe that memory (in our task) “spreads” during the 6 days following training. Since previous experiments have indicated that the central noradrenergic system is involved in this process of “memory spread”, we have examined the effect of stimulation or blockade of the α 2 -receptor. To this end, we adminstered a single dose of the α 2 -adrenoceptor antagonist, idazoxan, or the α 2 -agonist, clonidine. Idazoxan (1 mg/kg, SC) had no effect on engram spread. Clonidine (25 μg–125 ng/kg, SC), by contrast, suppressed engram spread for at least 30 days after treatment. When mice were tested at 60 and 90 days after treatment, spontaneous recovery (i.e., engram spread) was evident in only about 50% of the clonidine treated mice. Coadministration of idazoxan with clonidine blocked the effects of clonidine on “memory spread.”
Genetic and antigenic characterization of Babesia bovis merozoite spherical body protein Bb-1 *

A Babesia bovis merozoite protein, Bb-1, was localized by immunoelectron microscopy to an apical organelle known as the spherical body. This unique structure appears to be analogous to dense granules of other apicomplexan protozoa. Similar to previously described dense granule proteins of Plasmodium spp., Bb-1 is secreted during or just after invasion of host erythrocytes and becomes associated with the cytoplasmic face of the infected cell. The amino terminal sequence of Bb-1 contains a predicted signal peptide and is similar to the amino terminus of another spherical body protein (BvVA1/225) which is also translocated to the erythrocyte membrane. Importantly, these two spherical body proteins are the major components of a protective fraction of B. bovis antigen. There is marked conservation of Bb-1 amino acid sequences and B-lymphocyte epitopes among geographic strains. However, a divergent Bb-1 allele (Bv80) in Australia strains encodes six regions of amino acid polymorphism, including a region of tetrapeptide repeats in the C-terminal half of the polypeptide. Two of the polymorphic regions map to previously defined Th1 epitopes on Bb-1.