cssi/SciSciGPT-SciSciNet huggingface dataset:
Using Item Response Theory (IRT) to select hints in an ITS

Many Intelligent Tutoring Systems (ITSs) are designed to tutor students by providing error feedback and hints as students solve a series of problems, where the tutoring system's feedback is based on a model of the student's ability in the subject domain. Few ITSs, however, model the difficulty of the problems the student is solving, and those that do rarely utilize an empirical approach. Item Response Theory, a methodology applied in educational measurement, offers a way to empirically model both a student's ability and the difficulty of the problem on a common scale. This paper first describes a method for using Item Response Theory (IRT) to model the difficulty of the problems (items), which allows the system to determine the level of hints that students need during problem solving. Second, the paper reports on how the method was used in the FOSS Self-assessment System, an ITS developed to accompany part of a middle school science curriculum module. Finally, the paper presents the results of a study that compared three versions of the Self-assessment System to evaluate its efficacy, which showed that the methodology holds some promise, but needs further refinement and testing.
Labeling Solutions and Medications in Sterile Procedural Settings

Article-at-a-Glance Background Confusion resulting from unlabeled solutions and medications during sterile procedures can result in serious medication errors. Case Study During elective surgery, a seven-year-old boy was mistakenly injected with 100 times the intended dose of epinephrine. Cardiac arrest ensued, and the child died the next day. How One Hospital Met the Challenge At Marion General Hospital (Marion, Ohio), sterile procedures are performed in the surgery department, the cardiac catheterization lab, the labor and delivery area, intensive care unit rooms, and the emergency department. MGH's surgical services management team developed a policy and protocol for medication safety that refers to labeling of medications in sterile procedural settings. Discussion Sterile procedures often require medications or solutions to be placed in syringes or sterile basins. Facilities can eliminate the need for some solutions by using commercially available applicators or swabs, and can purchase some medications in sterile, labeled syringes. Sterile marking pens and blank sterile labels are available, as are preprinted sterile labels. The Association of periOperative Registered Nurses has helpful guidance statements and a medication safety toolkit. Conclusion This requirement can be challenging to meet, but good resources are available.
Two-Dimensional Scan Statistics

Let [0, T 1] × [0, T 2] be a rectangular region. Let h i = T i /N i > 0, where N i are positive integers, i = 1, 2. In many applications the exact locations of the observed events in the rectangular region are unknown. What is usually available are the counts in small rectangular subregions. For 1 ≤ i ≤ N 1 and 1 ≤ j ≤ N 2, let Xij be the number of events that have been observed in the rectangular subregion [(i−1)h l, ih l] × [(j−1)h 2, jh 2]. We are interested in detecting unusual clustering of these events under the null hypothesis that X ij are independent and identically distributed (i.i.d.) nonnegative integer valued random variables from a specified distribution.
Digermanide des Scandiums und Yttriums

Sc−Ge-, Sc−Si- und Y−Ge-Legierungen werden aus den Komponenten durch Erschmelzen im Lichtbogen oder im Induktionsofen hergestellt und mittels rontgenographischer Methoden untersucht. Es wird ein Digermanid ScGe2 aufgefunden, dessen Struktur mit ZrSi2 isotyp ist; die Gitterparameter sind:a=3,888 A,b=14,873 A,c=3,793 A. Im Y−Ge-System werden die Phasen Y2Ge3 und YGe2 festgestellt und strukturchemisch charakterisiert. Y2Ge3 besitzt AlB2-Defektstruktur mit:a=3,935 A,c=4,139 A undc/a=1,052; YGe2 kristallisiert mit ThSi2-Struktur und den Gitterabmessungen:a=4,060 A undc=13,683 A. Daneben werden noch zwei weitere Phasen im Bereich des Digermanids beobachtet. Im System: Sc−Si wird die Existenz eines Disilicids mit AlB2-Defektstruktur bestatigt.
A Bilayered Poly (Lactic-Co-Glycolic Acid) Scaffold Provides Differential Cues for the Differentiation of Dental Pulp Stem Cells.

Introduction: Regenerative Endodontics (RE) is a clinical procedure that aims to regenerate the dentin-pulp complex (DPC) inside the root canal. Current clinical outcomes of RE are unpredictable, and the regenerated tissue lacks the spatial organization seen in normal DPC. The purpose of this study was to develop and characterize in vitro a bilayered scaffold with distinct porosities on each side that supports differential penetration and odontoblastic differentiation of cultured human dental pulp stem cells (DPSCs). (DPSCs). Materials and Methods: Bilayered scaffolds were manufactured from poly (lactic-co-glycolic acid) (PLGA) using diffusion induced phase separation (DIPS). The layers were generated separately from 12% and 20% (w/v) PLGA and combined by lamination. Scaffold morphology was assessed by scanning electron microscopy. Human DPSCs were cultured on either side of the scaffold. Cell proliferation, viability, and penetration into the scaffolds were analyzed biochemically and by con...
High resolution measurement of tagged two-neutron energy and angle correlations in 252 Cf (sf)

Background: Spontaneous fission events emit prompt neutrons correlated with one another in emission angle and energy. Purpose: We explore the relationship in energy and angle between correlated prompt neutrons emitted from 252Cf spontaneous fission. Methods: Measurements with the Chi-Nu array provide experimental data for coincident neutrons tagged with a fission chamber signal with 10 degree angular resolution and 1 ns timing resolution for time-of-flight energy calculations. The experimental results are compared to simulations produced by the fission event generators CGMF, FREYA, and MCNPX-POLIMI IPOL(1)=1. Results: We find that the measurements and the simulations all exhibit anisotropic neutron emission, though differences exist between fission event generators. Conclusions: This work shows that the dependence of detected neutron energy on the energy of a neutron detected in coincidence, although weak, is non-negligible, indicating that there may be correlations in energy between two neutrons emitted in the same fission event.
MHC-Based Mating Preferences in Mus Operate through Both Settlement Patterns and Female Controlled Extra-Territorial Matings

We have recently demonstrated strong MHC-based mating preferences in semi-natural populations of Mus (Potts et al., 1991). These preferences are primarily responsible for a 27% deficiency of homozygotes (relative to random mating expectations) observed in nine independent experimental populations. The strength of these preferences is sufficient to explain the majority of MHC genetic diversity found in natural populations of Mus. Here we expand our analysis of the nature of these mating preferences. Although the majority of the MHC-related non-random mating appears to be controlled by females traveling to nearby territories to mate with the resident male, a significant proportion (approximately one quarter) is explained by settlement patterns. MHC-related non-random settlement patterns were primarily due to an excess of settlement pairs that share no MHC haplotypes. Because males may exercise control over which females settle on their territories, this component of MHC non-random mating provides an explanation for the presence of male controlled MHC-based mating preferences found in laboratory studies (Yamazaki et al. 1976; Yamazaki et al. 1978; Yamazaki et al. 1988). The prevalence of studies showing male MHC mating preferences (Beauchamp et al. 1988) has been theoretically troubling due to the expectation that females should be the choosier sex (Partridge, 1988; Nei and Hughes, 1991). A companion paper in this volume (Manning et al.) provides the theory and empirical support for why female MHC mate choice may be diminished or lost during inbreeding.
Shatkin: Cities for Profit: The Real Estate Turn in Asia’s Urban Politics

Cities for Profit: The Real Estate Turn in Asia’s Urban Politics is the culmination of more than 10 years of writing by Gavin Shatkin on urban megaprojects in southern Asia and Southeast Asia. Shat...
Filtering procedures for untargeted LC-MS metabolomics data

Untargeted metabolomics datasets contain large proportions of uninformative features that can impede subsequent statistical analysis such as biomarker discovery and metabolic pathway analysis. Thus, there is a need for versatile and data-adaptive methods for filtering data prior to investigating the underlying biological phenomena. Here, we propose a data-adaptive pipeline for filtering metabolomics data that are generated by liquid chromatography-mass spectrometry (LC-MS) platforms. Our data-adaptive pipeline includes novel methods for filtering features based on blank samples, proportions of missing values, and estimated intra-class correlation coefficients. Using metabolomics datasets that were generated in our laboratory from samples of human blood, as well as two public LC-MS datasets, we compared our data-adaptive filtering method with traditional methods that rely on non-method specific thresholds. The data-adaptive approach outperformed traditional approaches in terms of removing noisy features and retaining high quality, biologically informative ones. The R code for running the data-adaptive filtering method is provided at https://github.com/courtneyschiffman/Metabolomics-Filtering . Our proposed data-adaptive filtering pipeline is intuitive and effectively removes uninformative features from untargeted metabolomics datasets. It is particularly relevant for interrogation of biological phenomena in data derived from complex matrices associated with biospecimens.
Scoping New Policy Frameworks for Local Broadband Networks

Over many years, locally-initiated and operated broadband infrastructure projects have attempted to resolve the last-mile dilemma. Many generations of do-it-yourself (DIY) network efforts that are either wireless, such as community mesh networks, or wired, such as fiber cooperatives, exist, but in the U.S. scaled developments have been stalled for a variety of reasons that include regulatory prohibitions. This research examines a current ‘third wave’ of community networking, marked by local and DIY efforts as well as technological innovations. We investigate approaches that are technological, managerial, and also aimed at regulatory and economic incentives that may be appropriate in the U.S. We argue that this ‘third wave’ of community networking efforts and technology demonstrates new connectivity models that can solve some of the nation’s broadband problems, especially when accompanied by supportive federal and state policies. The technological, organization, and market implications of the third wave of community networks suggest new policies helpful to provide improved broadband services in various regions amidst incumbent protectionism.
Transforming Culture in Health Care.

Transforming Culture in Health Care Thinking of “culture” as a process in which tensions between social values are resolved, rather than as a fixed state, may help U.S. health care leaders envision...
Intractable Left Internal Mammary Artery Spasm After Coronary Artery Bypass Grafting.

Graft spasm is a rare but well-recognized complication of coronary artery bypass grafting (CABG). The occurrence of graft spam is multifactorial and can be fatal if not diagnosed and treated promptly. There are no well-defined guidelines for the management of a severe spasm. We report the case of a 29-year-old man with left internal mammary artery (LIMA) spasm in the immediate post-operative period following CABG. The intracoronary infusion of nitroglycerin relieved the spasm temporarily, confirming the diagnosis. The patient eventually underwent redo bypass grafting.
Examining Vocational Rehabilitation Services Provided to Incarcerated Persons With Disabilities

In the U.S. prison system, incarcerated persons with a disability represent a largely marginalized population with limited or inadequate provision of services in prison. In general, once released, ...
DRLindex: deep reinforcement learning index advisor for a cluster database

Cloud database providers provision different architectures to guarantee high availability. One of these architectures is a cluster database that consists of several database engine nodes, where data is replicated among the nodes. Although the cloud database providers provide various auto-indexing tools, these tools mostly address characteristics of a database deployed on a single node, not a cluster. It is possible to install an index advisor on each node, which recommends an index set for that node. The problem with this approach is that the current index advisors for a single node aim to minimize the processing cost of the workload; however, on a cluster database, other goals such as load balancing can be considered. Hence, the better solution could be an index advisor which has a comprehensive view of the cluster node. In this paper, we propose an index advisor for a replicated database on a database cluster for a read-only workload. The advisor considers both query processing cost and load balancing. It utilizes a Deep Reinforcement Learning (DRL) approach in which a DRL agent learns to select a set of index configurations for nodes in a cluster. We describe the components of the DRL-advisor such as the agent, the environment, a set of actions, the reward function, and other modules. Experimental results validate the effectiveness of the algorithm.
Do Programmers Prefer Predictable Expressions in Code

Source code is a form of human communication, albeit one where the information shared between the programmers reading and writing the code is constrained by the requirement that the code executes correctly. Programming languages are more syntactically constrained than natural languages, but they are also very expressive, allowing a great many different ways to express even very simple computations. Still, code written by developers is highly predictable, and many programming tools have taken advantage of this phenomenon, relying on language model surprisal as a guiding mechanism. While surprisal has been validated as a measure of cognitive load in natural language, its relation to human cognitive processes in code is still poorly understood. In this paper, we explore the relationship between surprisal and programmer preference at a small granularity-do programmers prefer more predictable expressions in code? Using meaning-preserving transformations, we produce equivalent alternatives to developer-written code expressions and run a corpus study on Java and Python projects. In general, language models rate the code expressions developers choose to write as more predictable than these transformed alternatives. Then, we perform two human subject studies asking participants to choose between two equivalent snippets of Java code with different surprisal scores (one original and transformed). We find that programmers do prefer more predictable variants, and that stronger language models like the transformer align more often and more consistently with these preferences.
Chronic lymphocytic leukemia B-cell-derived TNFα impairs bone marrow myelopoiesis.

Summary TNFα is implicated in chronic lymphocytic leukemia (CLL) immunosuppression and disease progression. TNFα is constitutively produced by CLL B cells and is a negative regulator of bone marrow (BM) myelopoiesis. Here, we show that co-culture of CLL B cells with purified normal human hematopoietic stem and progenitor cells (HSPCs) directly altered protein levels of the myeloid and erythroid cell fate determinants PU.1 and GATA-2 at the single-cell level within transitional HSPC subsets, mimicking ex vivo expression patterns. Physical separation of CLL cells from control HSPCs or neutralizing TNFα abrogated upregulation of PU.1, yet restoration of GATA-2 required TNFα neutralization, suggesting both cell contact and soluble-factor-mediated regulation. We further show that CLL patient BM myeloid progenitors are diminished in frequency and function, an effect recapitulated by chronic exposure of control HSPCs to low-dose TNFα. These findings implicate CLL B-cell-derived TNFα in impaired BM myelopoiesis.
Understanding Restaurant Healthfulness in Food Deserts.

Abstract Objective To determine differences in restaurant environments between neighborhood and restaurant type to understand better a food desert's eating environments. Methods The Nutrition Environment Measures Survey for restaurants was used to assess restaurant healthfulness. Kruskal-Wallis compared healthy index scores, and Pearson chi-square compared individual items. Results Healthy index scores were consistently low across neighborhoods (total mean = 4.6 out of 23). Fast-food restaurants (mean = 5.7) were more healthful than sit-down restaurants (mean = 3.1). Individual comparisons showed more healthy eating facilitators (eg, nutrition information at point-of-purchase, P = 0.004) in food deserts and more available healthful items (eg, whole grain bread, P Conclusions and Implications Findings indicate equities in restaurant environments across all neighborhoods but inequities across restaurant types, thus conclude the importance of restaurant type in understanding restaurant healthfulness. Policymakers can use these findings to develop healthy eating strategies in varying neighborhoods.
Automated Censorable Content Identification In Videos Using Deep Learning

Censorable scenes with smoking, heavy drinking, etc. are very common in movies of these days. Editors may find it too tedious a process to check the whole video to identify such censorable contents. We introduce an automated statutory warning generator that will add exact statutory labels to the scene. The system employs YOLOv3 based learning to include statutory alerts in videos. The results showed an accuracy of 85.34% mAP at 0.5 IOU and was found to be faster and efficient for detecting statutory contents from the videos thus reducing the time for movie editing.
RIFLE: Robust Inference from Low Order Marginals

The ubiquity of missing values in real-world datasets poses a challenge for statistical inference and can prevent similar datasets from being analyzed in the same study, precluding many existing datasets from being used for new analyses. While an extensive collection of packages and algorithms have been developed for data imputation, the overwhelming majority perform poorly if there are many missing values and low sample size, which are unfortunately common characteristics in empirical data. Such low-accuracy estimations adversely affect the performance of downstream statistical models. We develop a statistical inference framework for predicting the target variable without imputing missing values. Our framework, RIFLE (Robust InFerence via Low-order moment Estimations), estimates low-order moments with corresponding confidence intervals to learn a distributionally robust model. We specialize our framework to linear regression and normal discriminant analysis, and we provide convergence and performance guarantees. This framework can also be adapted to impute missing data. In numerical experiments, we compare RIFLE with state-of-the-art approaches (including MICE, Amelia, MissForest, KNN-imputer, MIDA, and Mean Imputer). Our experiments demonstrate that RIFLE outperforms other benchmark algorithms when the percentage of missing values is high and/or when the number of data points is relatively small. RIFLE is publicly available.
Must We Have the Right to Waste

Anglo-American law has long allowed an owner to do pretty much whatever she wants with her property, right down to the limiting case of using it all up or wasting it. The jus abutendi, or the "right of destroying or injuring [one's property] if one likes," has long been recognized as one of the basic rights in the "bundle of rights" that has come to symbolize property. On reflection, this affirmative right to waste is as puzzling - or ought to be - as it is entrenched. Where then did the right to waste come from? Why do we still have it to this day - indeed, why is it so taken for granted that we never seem to question it? More importantly, must we have it, as a descriptive matter? Should we continue to have it, as a normative one? This chapter explores these typically unexplored questions and argues against the continuance of the jus abutendi. It traces the evolution of the right to waste and shows its connections to an absolute conception of ownership developed largely in the context of an agrarian society and real property. It then canvasses what's wrong with waste from a political liberal point of view. This case takes on especial importance as value has moved away from land and into intangible, fungible units of value, paradigmatically money. A concern with wasting the family farm vel non has now become - or should properly become - a concern with depleting large stores of nominally private capital. The chapter concludes by proposing a revised conception of ownership with a practical law against waste, one that features a progressive consumption tax as its instantiation of the anti-waste norm. Among its other goals, the chapter thus aims at an important intellectual synthesis: the bringing of tax center stage in our thinking about property.
The Contact Process on a Homogeneous Tree

What is in this chapter? The contact process has the same birth and death rates as a particular branching Markov chain for which births occur only on nearest neighbor sites. The difference between the two models is that there is at most one particle per site for the contact process while there is no bound in the number of particles per site for branching Markov chains. So, branching Markov chains and the contact process may be thought of as two extreme points in the same class of models.
State Regulation of Religion and the Quality of Governance

The effect of state regulation of religion on governance has been explored theoretically by scholars, but it has not been tested empirically across nation states. The theory posits that secular states are more likely to benefit from better governance because of the absence of clerical involvement in politics, paving the way for the expansion of civil society and the passage of progressive political, economic, and social reforms. Using a unique dataset of more than 100 nation states, I find that countries with higher levels of state intervention on religion are more likely to suffer from inferior governance as reflected by higher levels of corruption and political instability and lower levels of rule of law entrenchment, bureaucratic effectiveness, and regulatory quality. Furthermore, states wherein there is no distinct separation between church and state are more likely to have lower levels of political openness and accountability. Related Articles Beal, Amanda L., and Leah Graham. 2014. “Foundations for Change: Rule of Law, Development, and Democratization.” Politics & Policy 42 (3): 311-345. http://onlinelibrary.wiley.com/doi/10.1111/polp.12077/abstract Flavin, Patrick, Alexander C. Pacek, and Benjamin Radcliff. 2011. “State Intervention and Subjective Well-Being in Advanced Industrial Democracies.” Politics & Policy 39 (2): 251-269. http://onlinelibrary.wiley.com/doi/10.1111/j.1747-1346.2011.00290.x/abstract Wagle, Udaya R. 2013. “The Heterogeneity Politics of the Welfare State: Changing Population Heterogeneity and Welfare State Policies in High-Income OECD Countries, 1980-2005.” Politics & Policy 41 (6): 947-984. http://onlinelibrary.wiley.com/doi/10.1111/polp.12053/abstract Related Media The Quality of Government Institute. http://www.qog.pol.gu.se/ The Association of Religion Data Archives. http://www.thearda.com/ J. M. Dawson Institute. Baylor University. http://www.baylor.edu/church_state/index.php?id=2566 El efecto de la regulacion estatal de la religion sobre la gobernanza ha sido explorado teoricamente por academicos pero dicho efecto no ha sido probado comparativamente. La teoria plantea que los estados laicos tienen mayor probabilidad de beneficiarse de una mejor gobernanza porque la ausencia de involucramiento de los clerigos en la politica allana el camino para la expansion de la sociedad civil y la aprobacion de reformas progresivas politicas, economicas y sociales. Al utilizar una base de datos unica que contiene los datos de mas de 100 estado-nacion, encuentro que las naciones con los mas altos niveles de intervencion estatal sobre la religion tienen una mayor probabilidad de sufrir una baja gobernanza reflejada en altos niveles de corrupcion, inestabilidad politica y bajos niveles de atrincheramiento del estado de derecho, eficacia burocratica y calidad de la regulacion. Mas aun, estados en los que no hay una clara separacion entre iglesia y estado tienen mayor probabilidad de tener menos niveles de apertura politica y rendicion de cuentas.
The General Smith: Early 19th Century Baltimore and the Supreme Court's Admiralty Jurisdiction

The General Smith is a minor admiralty case that established the home-port lien doctrine, a doctrine that was overturned by federal law over a century ago. The case itself has been mostly forgotten to history, and is but a footnote even to admiralty historians. Yet the story behind the case provides fascinating insight early 19th century Baltimore as a growing hub of trade and commerce in the years immediately after the War of 1812. The story behind the case reveals to us the colorful personalities of Baltimore’s early 19th century maritime merchants and lawyers. Most importantly, it helps to uncover surprising insights into the inner workings of the Supreme Court of the United States and clandestine efforts by the Court's personalities to enlarge the admiralty jurisdiction of the federal courts.
Selenium Dioxide Oxidation

Selenium dioxide has developed considerable stature since it was first reviewed in this series. Search for examples of oxidation by selenium dioxide or selenious acid is difficult because the terms are seldom indexed. Frequently it is difficult to decide whether selenium dioxide or selenious acid was the oxidizing agent employed in a reaction because it is impossible to determine if water was present. The determination is complex because the free acid or anhydride may react reversibly or irreversibly with various solvents such as alcohols or acids. To give selenium-containing compounds of unknown structure which might be the real oxidizing gents. In this chapter, the practical aspects of oxidation with selenium dioxide are summarized. Mechanisms are treated in detail. Keywords: selenium dioxide; oxidation; organoselenium compounds; allylic oxidations; aliphatic carbonyl compounds; experimental considerations
Breaking through an actin cloud

One of the puzzles about actin-based cellular motility is how directionality is spontaneously imparted in an initially symmetrical situation. A computer model representing actin filaments symmetrically surrounding a bead reproduces the experimentally observed symmetry-breaking and the directed motion of the bead.
Pharmacological Therapy for Anorexia Nervosa

People with anorexia nervosa have abnormal eating behaviors with associated cognitive misconceptions concerning body image and disturbances of mood as well as alterations of a wide variety of hormonal and metabolic systems (see Chapter2 for further description of anorexia nervosa). Currently, many investigators conceptualize these disorders as being caused by a combination of cultural-social, psychological, and biological factors (1,2). In general, the response of patients with anorexia nervosa to psychotherapeutic or pharmacological treatments has been limited. The purpose of this chapter is to review the evidence for the efficacy of available drug treatments for anorexia nervosa and guidelines for pharmacological therapy (Table 1).
A novel tunable matching network for dynamic load modulation of high power amplifiers

Dynamic load modulation (DLM) has been proposed as a promising technique to improve the backoff efficiency of power amplifier (PA) for wireless communication systems with high peak-to-average power ratio (PAPR), where the design of a tunable matching network (TMN) with wide impedance tuning range and low loss is essential. This work proposes a novel TMN circuit topology that has three main features satisfying closely to the requirements of DLM: able to generate impedance trajectory close to the pure resistance, easy to produce impedance trajectory of a wide tuning range, e.g., with reflection coefficient Gcoverage up to 0.9, and possessing high potential to generate a TMN having low loss especially at high G. A TMN circuit for load modulation of 2.14GHz Class-B GaN HEMT PAs based on the proposed topology is built and measured. Static measurements show that, given a properly selected PA, the drain efficiency is improved by 30% at 7.5dB backoff by the load modulation.
A nanoscale resolution view on synaptic vesicle dynamics

The ability of synapses to sustain neurotransmitter release during continuous activity critically relies on an efficient vesicle recycling program. Despite extensive research on synaptic function, the basic mechanisms of vesicle recycling remain poorly understood due to the relative inaccessibility of central synapses to conventional recording techniques. The extremely small size of synaptic vesicles, nearly five times below the diffraction-limited resolution of conventional light microscopy, has hampered efforts to define the mechanisms controlling their cycling. The complex sequence of dynamic processes that occur within the nerve terminals and link vesicle endocytosis and the subsequent round of release has been particularly difficult to study. The recent development of nanoscale-resolution imaging techniques has provided an opportunity to overcome these limitations and begin to reveal the mechanisms controlling vesicle recycling within individual nerve terminals. Here we summarize the recent advances in the implementation of super-resolution imaging and single-particle tracking approaches to study the dynamic steps of the vesicle recycling process within presynaptic terminals. Synapse, 69:256–267, 2015. © 2014 Wiley Periodicals, Inc.
Who determines teacher work: The teacher, the organization, or both?

Abstract This paper examines how teachers responded when some organizational constraints on their work were loosened and why they responded as they did. It first reviews the sociological literature on teacher work to identify the main determinants studied. It then presents results of an ethnographic study of teachers in an urban school. The literature tends to portray teacher work as overly determined and may remove more responsibility from teachers for determining their own work than is warranted.
Aminoglycoside inhibition of Staphylococcus aureus biofilm formation is nutrient dependent

Biofilms represent microbial communities, encased in a self-produced matrix or extracellular polymeric substance. Microbial biofilms are likely responsible for a large proportion of clinically significant infections and the multicellular nature of biofilm existence has been repeatedly associated with antibiotic resistance. Classical in vitro antibiotic-susceptibility testing utilizes artificial growth media and planktonic microbes, but this method may not account for the variability inherent in environments subject to biofilm growth in vivo. Experiments were designed to test the hypothesis that nutrient concentration can modulate the antibiotic susceptibility of Staphylococcus aureus biofilms. Developing S. aureus biofilms initiated on surgical sutures, and in selected experiments planktonic cultures, were incubated for 16 h in 66 % tryptic soy broth, 0.2 % glucose (1× TSBg), supplemented with bactericidal concentrations of gentamicin, streptomycin, ampicillin or vancomycin. In parallel experiments, antibiotics were added to growth medium diluted one-third (1/3× TSBg) or concentrated threefold (3× TSBg). Following incubation, viable bacteria were enumerated from planktonic cultures or suture sonicates, and biofilm biomass was assayed using spectrophotometry. Interestingly, bactericidal concentrations of gentamicin (5 µg gentamicin ml−1) and streptomycin (32 µg streptomycin ml−1) inhibited biofilm formation in samples incubated in 1/3× or 1× TSBg, but not in samples incubated in 3× TSBg. The nutrient dependence of aminoglycoside susceptibility is not only associated with biofilm formation, as planktonic cultures incubated in 3× TSBg in the presence of gentamicin also showed antibiotic resistance. These findings appeared specific for aminoglycosides because biofilm formation was inhibited in all three growth media supplemented with bactericidal concentrations of the cell wall-active antibiotics, ampicillin and vancomycin. Additional experiments showed that the ability of 3× TSBg to overcome the antibacterial effects of gentamicin was associated with decreased uptake of gentamicin by S. aureus. Uptake is known to be decreased at low pH, and the kinetic change in pH of growth medium from biofilms incubated in 5 µg gentamicin ml−1 in the presence of 3× TSBg was decreased when compared with pH determinations from biofilms formed in 1/3× or 1× TSBg. These studies underscore the importance of environmental factors, including nutrient concentration and pH, on the antibiotic susceptibility of S. aureus planktonic and biofilm bacteria.
Refolding active human DNA polymerase ν from inclusion bodies

Human DNA polymerase nu (Pol nu) is a conserved family A DNA polymerase of uncertain biological function. Physical and biochemical characterization aimed at understanding Pol nu function is hindered by the fact that, when over-expressed in Escherichia coli, Pol nu is largely insoluble, and the small amount of soluble protein is difficult to purify. Here we describe the use of high hydrostatic pressure to refold Pol nu from inclusion bodies, in soluble and active form. The refolded Pol nu has properties comparable to those of the small amount of Pol nu that was purified from the soluble fraction. The approach described here may be applicable to other DNA polymerases that are expressed as insoluble inclusion bodies in E. coli.
Discriminating between the nearfield and the farfield of acoustic transducers.

Measurements of the performance of acoustic transducers, as well as ordinary measurements made with the same, may require discriminating between the farfield, where the field is spherically divergent, and the complementary nearfield, where the field structure is more complicated. The problem is addressed for a planar circular piston projector, with uniform normal velocity distribution, mounted in an infinite planar rigid baffle. The inward-extrapolated farfield pressure amplitude pf is compared with the exact nearfield pressure amplitude pn, modeled by the Rayleigh integral, through the error 20 log |pf /pn|. Three sets of computations are performed for a piston with wavenumber-radius product ka = 10: normalized pressure amplitudes and error versus range at angles corresponding to beam pattern losses of 0, 10, 20, and 30 dB; error versus angle at three ranges, a2/λ, πa2/λ, and 10a2/λ, where λ is the wavelength; and range versus angle for each of two inward-bounded errors, 1 and 0.3 dB. By reciprocity, the...
A Weak Interaction between Iron and Uranium in Uranium Alkyl Complexes Supported by Ferrocene Diamide Ligands

Alkyl complexes of uranium supported by ferrocene diamide ligands are described along with the corresponding cationic species. Synthesis of uranium dialkyl compounds fc(NSitBuMe2)2UR2 [R = Np (neo-pentyl), Bz (benzyl)] was accomplished by salt metathesis between fc(NSitBuMe2)2UI2(THF) and neo-pentyl lithium or benzyl potassium. Protonation of one alkyl ligand led to the isolation of a cationic uranium alkyl complex. DFT calculations and X-ray crystallography data support the existence of a donor–acceptor, weak interaction between iron and uranium.
Matrix Metalloproteinase-Induced Epithelial-Mesenchymal Transition in Breast Cancer

Matrix metalloproteinases (MMPs) degrade and modify the extracellular matrix (ECM) as well as cell-ECM and cell-cell contacts, facilitating detachment of epithelial cells from the surrounding tissue. MMPs play key functions in embryonic development and mammary gland branching morphogenesis, but they are also upregulated in breast cancer, where they stimulate tumorigenesis, cancer cell invasion and metastasis. MMPs have been investigated as potential targets for cancer therapy, but clinical trials using broad-spectrum MMP inhibitors yielded disappointing results, due in part to lack of specificity toward individual MMPs and specific stages of tumor development. Epithelial-mesenchymal transition (EMT) is a developmental process in which epithelial cells take on the characteristics of invasive mesenchymal cells, and activation of EMT has been implicated in tumor progression. Recent findings have implicated MMPs as promoters and mediators of developmental and pathogenic EMT processes in the breast. In this review, we will summarize recent studies showing how MMPs activate EMT in mammary gland development and in breast cancer, and how MMPs mediate breast cancer cell motility, invasion, and EMT-driven breast cancer progression. We also suggest approaches to inhibit these MMP-mediated malignant processes for therapeutic benefit.
Relational Uncertainty as a Consequence of Partner Jealousy Expressions

The present study examines how the relational-uncertainty levels of individuals whose partners are jealous (i.e., “jealousy targets”) are predicted by how partners express jealousy. Students and community members completed a questionnaire where they recalled an instance when they were the recipients of their romantic partners' expression of jealousy. In general, jealousy-target relational uncertainty was positively predicted by a majority of negative and general behavioral partner jealousy expressions. However, positive partner jealousy expressions were not generally associated with jealousy-target relational uncertainty. Implications for the theoretical understanding of relational uncertainty and consequences of partner jealousy expression are discussed.
A generic bioheat transfer thermal model for a perfused tissue.

A thermal model was needed to predict temperatures in a perfused tissue, which satisfied the following three criteria. One, the model satisfied conservation of energy. Two, the heat transfer rate from blood vessels to tissue was modeled without following a vessel path. Three, the model applied to any unheated and heated tissue. To meet these criteria, a generic bioheat transfer model (BHTM) was derived here by conserving thermal energy in a heated vascularized finite tissue and by making a few simplifying assumptions. Two linear coupled differential equations were obtained with the following two variables: tissue volume averaged temperature and blood volume averaged temperature. The generic model was compared with the widely employed empirical Pennes’ BHTM. The comparison showed that the Pennes’ perfusion term wCp(1−e) should be interpreted as a local vasculature dependent heat transfer coefficient term. Suggestions are presented for further adaptations of the general BHTM for specific tissues using imaging techniques and numerical simulations.
A Minimum Calculus for Logic

A logical calculus will be presented which not only is a formulation of a “basic logic” in the sense of the writer's previous papers, but which has the additional property that no weaker calculus can be a formulation of a basic logic. A sort of minimum logical calculus is thus attained, which has nothing superfluous about it for achieving the purpose for which it is designed. In the case of some logical calculi the question can arise as to whether certain of the postulates are really logically valid and necessary. Sometimes a test is available, such as the truth-table test, enabling us to distinguish between logically valid sentences and others, but often no such test is available, especially where quantifiers are involved. Is or is not the axiom of infinity, for example, to be regarded as logically valid? Or is the principle of double negation really acceptable, even though it satisfies the truth-table test?
The Masson Trichrome Staining Methods in Routine Laboratory Use

A resume of Masson's trichrome staining methods is given, with detailed directions for carrying out all of his procedures. The results obtained thru their use in a routine laboratory are discussed ...
Electoral consequences of declining participation: A natural experiment in Austria

Participation rates have declined sharply across developed democracies. But the precise impact of this decline on party systems has proven difficult to study due to endogeneity concerns. This paper seeks to address this issue by leveraging a natural experiment in Austrian parliamentary elections. By examining instances in which compulsory voting was gradually repealed in a federal setting, I isolate the causal relationship between turnout decline and subsequent shifts in party vote share. The findings suggest that turnout decline is not associated with a significant redistribution of votes between parties. The clearest visible effect is a consolidation of the party system, with a mild shift in votes from minor to mainstream parties. Evaluating the findings, the paper argues that characteristics of proportional representation systems insulate parties against the consequences of declining electoral participation.
Comparison of methods for positional analysis: Structural and general equivalences☆

Abstract This paper explores the conceptualization and measurement of social position in relational data. It is argued that social positions are evidenced in the interactions among individuals, which are encoded in measured social relations. Given a set of measured relations the task is to reveal social positions which consist of groups of individuals wth similar patterns of relations. Methods based on two alternative approaches are discussed. The first set of approaches is based on structural equivalence, and locates groups of similar individuals based on the extent to which they share identical ties with identical others. A second set of approaches, here called general equivalences, locates groups of similar individuals based on their sharing of “types” of ties with “types” of others. Procedures based on these different approaches are described and applied to actual data and to a constructed example. Results suggest that these different approaches identify different kinds of social groups. It is argued that structural equivalence is an unsuitable basis for analysis of relational data if the goal is detection of social positions.
Predictors of perceived work-family balance: Gender difference or gender similarity?

This article uses the 1996 General Social Survey (GSS) and the 1992 National Study of the Changing Workforce (NSCW) to examine two issues: the relationship of work characteristics, family characteristics, and work-family spillover to perceptions of work-family balance; and models of “gender difference” versus “gender similarity.” The GSS analysis supports the gender similarity model. It demonstrates that work demands such as the number of hours worked per week and work spillover into family life are the most salient predictors of feelings of imbalance for both women and men. The NSCW includes subtler measures of family spillover into work as well as measures of specific job characteristics and child care. The NSCW results support a gender difference model. They indicate that when family demands reduce work quality, there is a decreased likelihood of perceived balance. However, men and women experience balance in gendered ways. Women report more balance when they give priority to family; men report less ba...
Understanding toilet training difficulties.

Toileting skills are acquired through 2 simultaneous, reciprocal processes: toilet training (what parents do to help their child toward socially appropriate, self-sufficient toileting) and toilet learning (what a child thinks and does while learning the mores of elimination behavior, how to recognize sensory signals, how to choose whether to void, and how to control anal and urethral sphincters in implementing that choice). This learning process can be derailed, resulting in functional disorders of elimination. In this issue of Pediatrics , Schonwald et al1 infer that toilet training difficulties are associated with difficult temperament traits. Although constipation was more prevalent in their patients than in their normal control group, constipation nevertheless affected 55% of the latter. This result begged the question: Does constipation also contribute to toilet training difficulties, or is it a secondary epiphenomenon? In this month’s Pediatrics Electronic Pages , Blum et al2 confirm that constipation is contributory to the type of difficulty referred to as stool toileting refusal rather than a result of … Address correspondence to David R. Fleisher, MD, University of Missouri School of Medicine, One Hospital Drive, Columbia, MO 65212. E-mail: fleisherd{at}health.missouri.edu
Assessment of ovarian function with anti-Müllerian hormone in systemic lupus erythematosus patients undergoing hematopoietic stem cell transplant

In this small pilot study, anti-Mullerian hormone (AMH) levels in women undergoing chemotherapy and hematopoietic stem cell transplantation facilitated earlier identification of impaired ovarian reserve compared with FSH and the resumption of menses. Larger studies are needed to accurately assess the clinical significance of AMH levels in the prediction of long-term reproductive outcomes in reproductive-age transplant patients with our current conditioning regimen.
The effect of imposing a corner condition on the evolution of two-dimensional crystal morphologies by surface diffusion with anisotropic surface free energies

Abstract Continuity of the chemical potential is required from the physics of the evolution of crystal morphology by surface diffusion and in equilibrium crystal shapes (ECS). With an anisotropic surface free energy, multiple ECS with corners have been reported and instability developed in computing evolution of crystal morphology. For a cornered ECS that minimizes the total surface free energy, a corner condition is needed. Hence, in addition to continuity of the chemical potential, we add the corner condition in the evolution of crystal morphology and ensure the condition is satisfied in the numerical computation of the evolving surfaces. The evolution is governed by a nonlinear 4th order time dependent partial differential equation. By enforcing the corner condition, we obtain better stability in the evolution, which leads to ECS having lower total surface free energies than those obtained previously without satisfying the corner condition. Our study shows that the corner condition plays an important role for the cases of critically and severely anisotropic surface free energies that yield surface corners and facets.