cssi/SciSciGPT-SciSciNet huggingface dataset:
Welfare-maximizing Guaranteed Dashboard Mechanisms

Bidding dashboards are used in online marketplaces to aid a bidder in computing good bidding strategies, particularly when the auction used by the marketplace is constrained to have the winners-pay-bid payment format. A dashboard predicts the outcome a bidder can expect to get at each possible bid. To convince a bidder to best respond to the information published in a dashboard, a dashboard mechanism should ensure either (a) that best responding maximizes the bidder's utility (a weaker requirement) or (b) that the mechanism implements the outcome published in the dashboard (a stronger requirement that subsumes (a)). Recent work by Hartline et al. EC'19 formalized the notion of dashboard mechanisms and designed winners-pay-bid mechanisms that guaranteed epsilon-optimal utility (an epsilon-approximate version of (a)), but not (b). I.e., the mechanism could end up implementing arbitrarily different outcomes from what was promised. While this guarantee is sufficient from a purely technical perspective, it is far from enough in the real world: it is hard to convince bidders to best respond to information which could be arbitrarily inaccurate, regardless of the theoretical promise of near-optimality. In this paper we study guaranteed dashboard mechanisms, namely, ones that are guaranteed to implement what they publish, and obtain good welfare. We study this question in a repeated auction setting for general single-dimensional valuations and give tight characterizations of the loss in welfare as a function of natural parameters upper bounding the difference in valuation profile across the rounds. In particular, we give three different characterizations, bounding the loss in welfare in terms of the 0 norm, 1 norm and infinite norm of difference in valuation profile across rounds. All the characterizations generalize at least up to matroid feasibility constraints, and the infinite norm characterization extends to general downward-closed feasibility constraints. We bring to bear different techniques for each of these characterizations, including connections to differential privacy and online convex optimizations.
Noise reduction in X-ray photon correlation spectroscopy with convolutional neural networks encoder–decoder models

Like other experimental techniques, X-ray photon correlation spectroscopy is subject to various kinds of noise. Random and correlated fluctuations and heterogeneities can be present in a two-time correlation function and obscure the information about the intrinsic dynamics of a sample. Simultaneously addressing the disparate origins of noise in the experimental data is challenging. We propose a computational approach for improving the signal-to-noise ratio in two-time correlation functions that is based on convolutional neural network encoder–decoder (CNN-ED) models. Such models extract features from an image via convolutional layers, project them to a low dimensional space and then reconstruct a clean image from this reduced representation via transposed convolutional layers. Not only are ED models a general tool for random noise removal, but their application to low signal-to-noise data can enhance the data’s quantitative usage since they are able to learn the functional form of the signal. We demonstrate that the CNN-ED models trained on real-world experimental data help to effectively extract equilibrium dynamics’ parameters from two-time correlation functions, containing statistical noise and dynamic heterogeneities. Strategies for optimizing the models’ performance and their applicability limits are discussed.
Mapping the biosynthetic pathway of a hybrid polyketide-nonribosomal peptide in a metazoan.

Polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) hybrid systems typically use complex protein-protein interactions to facilitate direct transfer of intermediates between these multimodular megaenzymes. In the canal-associated neurons (CANs) of Caenorhabditis elegans, PKS-1 and NRPS-1 produce the nemamides, the only known hybrid polyketide-nonribosomal peptides biosynthesized by animals, through a poorly understood mechanism. Here, we use genome editing and mass spectrometry to map the roles of individual PKS-1 and NRPS-1 enzymatic domains in nemamide biosynthesis. Furthermore, we show that nemamide biosynthesis requires at least five additional enzymes expressed in the CANs that are encoded by genes distributed across the worm genome. We identify the roles of these enzymes and discover a mechanism for trafficking intermediates between a PKS and an NRPS. Specifically, the enzyme PKAL-1 activates an advanced polyketide intermediate as an adenylate and directly loads it onto a carrier protein in NRPS-1. This trafficking mechanism provides a means by which a PKS-NRPS system can expand its biosynthetic potential and is likely important for the regulation of nemamide biosynthesis. The only known animal polyketide-nonribosomal peptides, the nemamides, are biosynthesized by two megasynthetases in the canal-associated neurons (CANs) of C. elegans. Here, the authors map the biosynthetic roles of individual megasynthetase domains and identify additional enzymes in the CANs required for nemamide biosynthesis.
Updated simulation tools for Roman coronagraph PSFs

The Nancy Grace Roman Space Telescope Coronagraph Instrument will be the first large scale coronagraph mission with active wavefront control to be operated in space and will demonstrate technologies essential to future missions to image Earth-like planets. Consisting of multiple coronagraph modes, the coronagraph is expected to characterize and image exoplanets at 1E-8 or better contrast levels. An object-oriented physical optics modeling tool called POPPY provides flexible and efficient simulations of high-contrast point spread functions (PSFs). As such, three coronagraph modes have been modeled in POPPY. In this paper, we present the recent testing results of the models and provide quantitative comparisons between results from POPPY and existing tools such as PROPER/FALCO. These comparisons include the computation times required for PSF calculations. In addition, we discuss the future implementation of the POPPY models for the POPPY front-end package WebbPSF, a widely used simulation tool for JWST PSFs.
The closure-complement-frontier problem in saturated polytopological spaces

Let $X$ be a space equipped with $n$ topologies $\tau_1,\ldots,\tau_n$ which are pairwise comparable and saturated, and for each $1\leq i\leq n$ let $k_i$ and $f_i$ be the associated topological closure and frontier operators, respectively. Inspired by the closure-complement theorem of Kuratowski, we prove that the monoid of set operators $\mathcal{KF}_n$ generated by $\{k_i,f_i:1\leq i\leq n\}\cup\{c\}$ (where $c$ denotes the set complement operator) has cardinality no more than $2p(n)$ where $p(n)=\frac{5}{24}n^4+\frac{37}{12}n^3+\frac{79}{24}n^2+\frac{101}{12}n+2$. The bound is sharp in the following sense: for each $n$ there exists a saturated polytopological space $(X,\tau_1,...,\tau_n)$ and a subset $A\subseteq X$ such that repeated application of the operators $k_i, f_i, c$ to $A$ will yield exactly $2p(n)$ distinct sets. In particular, following the tradition for Kuratowski-type problems, we exhibit an explicit initial set in $\mathbb{R}$, equipped with the usual and Sorgenfrey topologies, which yields $2p(2)=120$ distinct sets under the action of the monoid $\mathcal{KF}_2$.
RADIATION-INDUCED GROWTH OF MICRO CRYSTALLITES

Generation of colloidal particles during the radiolysis of aqueous solutions was already observed in the early days of radiation chemistry. Systematic studies using radiation chemistry techniques as synthetic tools in the preparation of colloidal particles, primarily metallic particles, were begun approximately a decade ago in conjunction since they were found to catalyze multi-electron redox processes. A large number of metallic colloidal particles were then synthesized, including silver, gold, platinum, iridium, nickel, cadmium, and others. More recently, attention has turned to semiconductor colloidal particles. The stimulus to these studies is the observation of quantum size effects in small semiconductor particles that exhibit hybrid properties between those of the molecular species and the solid state bulk material. In the following we discuss our own observations on the evolution of semiconductor particles whose growth has been initiated by pulse radiolysis. 13 refs., 2 figs.
Interhemispheric Functional Connectivity in the Primary Motor Cortex Distinguishes Between Training on a Physical and a Virtual Surgical Simulator

Functional brain connectivity using functional near-infrared spectroscopy (fNIRS) during a pattern cutting (PC) task was investigated in physical and virtual simulators. 14 right-handed novice medical students were recruited and divided into separate cohorts for physical (N = 8) and virtual (N = 6) PC training. Functional brain connectivity measured were based on wavelet coherence (WCOH) from task-related oxygenated hemoglobin (HBO2) changes from baseline at left and right prefrontal cortex (LPFC, RPFC), left and right primary motor cortex (LPMC, RPMC), and supplementary motor area (SMA). HBO2 changes within the neurovascular frequency band (0.01–0.07 Hz) from long-separation channels were used to compute average inter-regional WCOH metrics during the PC task. The coefficient of variation (CoV) of WCOH metrics and PC performance metrics were compared. WCOH metrics from short-separation fNIRS time-series were separately compared. Partial eta squared effect size (Bonferroni correction) between the physical versus virtual simulator cohorts was found to be highest for LPMC-RPMC connectivity. Also, the percent change in magnitude-squared WCOH metric was statistically (p < 0.05) different for LPMC-RPMC connectivity between the physical and the virtual simulator cohorts. Percent change in WCOH metrics from extracerebral sources was not different at the 5% significance level. Also, higher CoV for both LPMC-RPMC magnitude-squared WCOH metric and PC performance metrics were found in physical than a virtual simulator. We conclude that interhemispheric connectivity of the primary motor cortex is the distinguishing functional brain connectivity feature between the physical versus the virtual simulator cohorts. Brain-behavior relationship based on CoV between the LPMC-RPMC magnitude-squared WCOH metric and the FLS PC performance metric provided novel insights into the neuroergonomics of the physical and virtual simulators that are crucial for validating Virtual Reality technology.
ECACL: A Holistic Framework for Semi-Supervised Domain Adaptation

This paper studies Semi-Supervised Domain Adaptation (SSDA), a practical yet under-investigated research topic that aims to learn a model of good performance using unlabeled samples and a few labeled samples in the target domain, with the help of labeled samples from a source domain. Several SSDA methods have been proposed recently, which however fail to fully exploit the value of the few labeled target samples. In this paper, we propose Enhanced Categorical Alignment and Consistency Learning (ECACL), a holistic SSDA framework that incorporates multiple mutually complementary domain alignment techniques. ECACL includes two categorical domain alignment techniques that achieve class-level alignment, a strong data augmentation based technique that enhances the model's generalizability and a consistency learning based technique that forces the model to be robust with image perturbations. These techniques are applied on one or multiple of the three inputs (labeled source, unlabeled target, and labeled target) and align the domains from different perspectives. ECACL unifies them together and achieves fairly comprehensive domain alignments that are much better than the existing methods: For example, ECACL raises the state-of-the-art accuracy from 68.4 to 81.1 on VisDA2017 and from 45.5 to 53.4 on DomainNet for the 1-shot setting. Our code is available at \url{this https URL}.
Characterization of Brownian Gibbsian line ensembles

In this paper we show that a Brownian Gibbsian line ensemble is completely characterized by the finite-dimensional marginals of its top curve, that is, the finite-dimensional sets of the top curve form a separating class. A particular consequence of our result is that the parabolic Airy line ensemble is the unique Brownian Gibbsian line ensemble, whose top curve is the parabolic Airy2 process.
Mem3DG: Modeling Membrane Mechanochemical Dynamics in 3D using Discrete Differential Geometry

Biomembranes adopt varying morphological configurations that are vital to cellular functions. Many studies use computational modeling to understand how various mechanochemical factors contribute to membrane shape transformations. Compared to traditional approximation-based methods (e.g., finite element method), the class of discrete mesh models offers greater flexibility to simulate complex physics and shapes in three dimensions; its formulation produces an efficient algorithm while maintaining expressive coordinate-free geometric descriptions. However, ambiguities in geometric definitions in the discrete context have led to a lack of consensus on which discrete-mesh-based model is theoretically and numerically optimal; a bijective relationship between the terms contributing to both the energy and forces from the discrete and smooth geometric theories remains to be established. We address this and present an extensible framework, Mem3DG, for modeling 3D mechanochemical dynamics of membranes based on Discrete Differential Geometry (DDG) on triangulated meshes. The formalism of DDG resolves the inconsistency and provides a unifying perspective on how to relate the smooth and discrete energy and forces. Mem3DG is designed to facilitate models in tandem with and mimicking experimental studies. It also supports the use of realistic membrane ultrastructure from 3D imaging as an input. To demonstrate, Mem3DG is used to model a sequence of examples with increasing mechanochemical complexity: recovering classical shape transformations such as 1) biconcave disk, dumbbell, and unduloid and 2) spherical bud on spherical, flat-patch membrane; investigating how the coupling of membrane mechanics with protein mobility jointly affects phase and shape transformation. While the first two examples serve as validation, the later examples provide a blueprint for extending Mem3DG to model a system of interest. As high-resolution 3D imaging of membrane ultrastructure becomes more readily available, we envision Mem3DG to be applied as an end-to-end tool to simulate realistic cell geometry under user-specified mechanochemical conditions. We hope that Mem3DG will be a useful tool to help advance the mission of computational membrane mechanobiology.
Robustness of Collective Scenting in the Presence of Physical Obstacles

Honey bees (Apis mellifera L.) aggregate around the queen by collectively organizing a communication network to propagate volatile pheromone signals. Our previous study shows that individual bees “scent” to emit pheromones and fan their wings to direct the signal flow, creating an efficient search and aggregation process. In this work, we introduce environmental stressors in the form of physical obstacles that partially block pheromone signals and prevent a wide open path to the queen. We employ machine learning methods to extract data from the experimental recordings, and show that in the presence of an obstacle that blocks most of the path to the queen, the bees need more time but can still effectively employ the collective scenting strategy to overcome the obstacle and aggregate around the queen. Further, we increase the complexity of the environment by presenting the bees with a maze to navigate to the queen. The bees require more time and exploration to form a more populated communication network. Overall, we show that given volatile pheromone signals and only local communication, the bees can collectively solve the swarming process in a complex unstructured environment with physical obstacles and hit a limit when the obstacle is a much more complex maze.
Treatment Planning System for Electron FLASH Radiotherapy: Open-source for Clinical Implementation.

Abstract Purpose: A Monte Carlo (MC) beam model and its implementation in a clinical treatment planning system (TPS, Varian Eclipse) are presented for a modified ultra-high dose-rate electron FLASH radiotherapy LINAC (eFLASH-RT) utilizing clinical accessories and geometry. Methods: The gantry head without scattering foils or targets, representative of the LINAC modifications, was modelled in Geant4-based GAMOS MC toolkit. The energy spectrum (σE) and beam source emittance cone angle (θcone) were varied to match the calculated open field central-axis percent depth dose (PDD) and lateral profiles with Gafchromic film measurements. The beam model and its Eclipse configuration were validated with measured profiles of the open field and nominal fields for clinical applicators. A MC forward dose calculation was conducted for a mouse whole brain treatment and an eFLASH-RT plan was compared to a conventional (Conv-RT) electron plan in Eclipse for a human patient with metastatic renal cell carcinoma. Results: The eFLASH beam model agreed best with measurements at σE=0.5 MeV and θcone=3.9±0.2 degrees. The model and its Eclipse configuration were validated to clinically acceptable accuracy (the absolute average error was within 1.5% for in-water lateral, 3% for in-air lateral, and 2% for PDD's). The forward calculation showed adequate dose delivery to the entire mouse brain, while sparing the organ-at-risk (lung). The human patient case demonstrated the planning capability with routine accessories to achieve an acceptable plan (90% of the tumor volume receiving 95% and 90% of the prescribed dose for eFLASH and conventional, respectively). Conclusion: To the best of our knowledge, this is the first functional beam model commissioned in a clinical TPS for eFLASH-RT, enabling planning and evaluation with minimal deviation from Conv-RT workflow. It facilitates the clinical translation as eFLASH-RT and Conv-RT plan quality were comparable for a human patient involving complex geometries and tissue heterogeneity. The methods can be expanded to model other eFLASH irradiators with different beam characteristics.
Model-Order-Reduction Approach for Structural Health Monitoring of Large Deployed Structures With Localized Operational Excitations

We present a simulation-based classification approach for large deployed structures with localized operational excitations. The method extends the two-level Port-Reduced Reduced-Basis Component (PR-RBC) technique to provide faster solution estimation to the hyperbolic partial differential equation of time-domain elastodynamics with a moving load. Time-domain correlation function-based features are built in order to train classifiers such as artificial neural networks and perform damage detection. The method is tested on a bridge example with a moving vehicle (playing the role of a digital twin) in order to detect cracks' existence. Such problem has $45$ parameters and shows the merits of the two-level PR-RBC approach and of the correlation function-based features in the context of operational excitations, other nuisance parameters and added noise. The quality of the classification task is enhanced by the sufficiently large synthetic training dataset and the accuracy of the numerical solutions, reaching test classification errors below $0.1\%$ for disjoint training set of size $7\times10^3$ and test set of size $3\times10^3$.
Universal Off-Policy Evaluation

When faced with sequential decision-making problems, it is often useful to be able to predict what would happen if decisions were made using a new policy. Those predictions must often be based on data collected under some previously used decision-making rule. Many previous methods enable such off-policy (or counterfactual) estimation of the expected value of a performance measure called the return. In this paper, we take the first steps towards a universal off-policy estimator (UnO) -- one that provides off-policy estimates and high-confidence bounds for any parameter of the return distribution. We use UnO for estimating and simultaneously bounding the mean, variance, quantiles/median, inter-quantile range, CVaR, and the entire cumulative distribution of returns. Finally, we also discuss Uno's applicability in various settings, including fully observable, partially observable (i.e., with unobserved confounders), Markovian, non-Markovian, stationary, smoothly non-stationary, and discrete distribution shifts.
The mental health impact of COVID-19 racial and ethnic discrimination against Asian American and Pacific Islanders

Hate crimes against Asian American/ Pacific Islanders (AAPI) have surged in the United States during the COVID-19 pandemic to alarming new levels. We analyzed data from the Healthy Minds Study, and found that COVID-19 related racial/ethnic discrimination was associated with greater odds of having depression, anxiety, non-suicidal self-injury, binge drinking, and suicidal ideation among AAPI university students (N=1697). Findings suggest that the COVID-19 pandemic precipitated discrimination, which has been linked to mental health problems, calling for more preventive interventions to address the AAPI population, especially given their low rates of formal treatment utilization.
A Sample of Massive Black Holes in Dwarf Galaxies Detected via [Fe x] Coronal Line Emission: Active Galactic Nuclei and/or Tidal Disruption Events

The massive black hole (BH) population in dwarf galaxies ($M_{\rm BH} \lesssim 10^5~M_\odot$) can provide strong constraints on the origin of BH seeds. However, traditional optical searches for active galactic nuclei (AGNs) only reliably detect high-accretion, relatively high-mass BHs in dwarf galaxies with low amounts of star formation, leaving a large portion of the overall BH population in dwarf galaxies relatively unexplored. Here, we present a sample of 81 dwarf galaxies ($M_\star \le 3 \times 10^9~M_\odot$) with detectable [Fe X]$\lambda$6374 coronal line emission indicative of accretion onto massive BHs, only two of which were previously identified as optical AGNs. We analyze optical spectroscopy from the Sloan Digital Sky Survey and find [Fe X]$\lambda$6374 luminosities in the range $L_{\rm [Fe\,X]}\approx10^{36}$-$10^{39}$ erg s$^{-1}$, with a median value of $1.6 \times 10^{38}$ erg s$^{-1}$. The [Fe X]$\lambda$6374 luminosities are generally much too high to be produced by stellar sources, including luminous Type IIn supernovae (SNe). Moreover, based on known SNe rates, we expect at most 8 Type IIn SNe in our sample. On the other hand, the [Fe X]$\lambda$6374 luminosities are consistent with accretion onto massive BHs from AGNs or tidal disruption events (TDEs). We find additional indicators of BH accretion in some cases using other emission line diagnostics, optical variability, X-ray and radio emission (or some combination of these). However, many of the galaxies in our sample only have evidence for a massive BH based on their [Fe X]$\lambda$6374 luminosities. This work highlights the power of coronal line emission to find BHs in dwarf galaxies missed by other selection techniques and to probe the BH population in bluer, lower mass dwarf galaxies.
Empirical evaluation of adaptive user modeling in a medical information retrieval application

A comprehensive methodology for evaluating a user model presents challenges in choosing metrics and in assessing usefulness from both user and system perspectives. In this paper, we describe such a methodology and use it to assess the effectiveness of an adaptive user model embedded in a medical information retrieval. We demonstrate that the user model helps to improve the retrieval quality without degrading the system performance and identify usability problems overlooked in the user model architecture. Empirical data help us in analyzing drawbacks in our user model and develop solutions.
Influence of a strong-binding myosin analogue on calcium-sensitive mechanical properties of skinned skeletal muscle fibers.

The ability of strong-binding myosin heads to activate the thin filament was investigated by incubating skinned single muscle fibers with N-ethylmaleimide-(NEM) modified myosin subfragment-1 (S1). Isometric force was influenced in a complex manner: during maximal calcium activation, NEM-S1 inhibited force with half-maximal inhibition at 20 microM while at submaximal calcium, NEM-S1 potentiated force with greatest effect at 6 microM. When fibers were treated with NEM-S1 (4-8 microM), the tension-pCa (-log [Ca2+]) relationship became less steep (i.e. the Hill coefficient decreased from 5.4 to 3.0 upon treatment with NEM-S1), but the midpoint was unchanged. These results support the idea that strong binding of intrinsic heads contributes to the cooperativity observed in Ca2+ activation of force. The NEM-S1-induced increase in force at low Ca2+ was associated with an acceleration of a kinetic transition, and this transition was activated to near maximum while force was not. The rate of force redevelopment following restretch (ktr) at submaximal calcium was increased by NEM-S1 in a concentration-dependent manner, yielding a maximum rate at low [Ca2+] which was similar to that observed during full activation. The effects of NEM-S1 on force and ktr indicate that strong-binding myosin cross-bridges are involved in activation of the thin filament.
Assessing strategies to minimize unintended fitness consequences of aquaculture on wild populations

Artificial propagation programs focused on production, such as commercial aquaculture or forestry, entail strong domestication selection. Spillover from such programs can cause unintended fitness and demographic consequences for wild conspecifics. The range of possible management practices to minimize such consequences vary in their control of genetic and demographic processes. Here, we use a model of coupled genetic and demographic dynamics to evaluate alternative management approaches to minimizing unintended consequences of aquaculture escapees. We find that, if strong natural selection occurs between escape and reproduction, an extremely maladapted (i.e., nonlocal-origin, highly domesticated) stock could have fitness consequences analogous to a weakly diverged cultured stock; otherwise, wild population fitness declines with increasing maladaptation in the cultured stock. Reducing escapees through low-level leakage is more effective than reducing an analogous number of escapees from large, rare pulses. This result arises because low-level leakage leads to the continual lowering of wild population fitness and subsequent increased proportional contribution of maladapted cultured escapees to the total population. Increased sterilization efficacy can cause rapid, nonlinear reductions in unintended fitness consequences. Finally, sensitivity to the stage of escape indicates a need for improved monitoring data on how the number of escapees varies across life cycle stages.
Electrical and Magnetic Properties of β-Carotene Triiodide

CHARGE–TRANSFER complexes formed between iodine and condensed ring aromatic hydrocarbons have been studied in some detail recently, most extensively by Akamatu, Inokuchi, Matsunaga and their co-workers1. We should like here to point out that iodine also reacts with β-carotene, a non-aromatic hydrocarbon containing eleven conjugated double bonds, to form a compound exhibiting electrical and magnetic properties similar to those of iodine-aromatic charge–transfer complexes. The stoichiometric formula of this compound is C40H56I3; that is, it contains three iodine atoms per β-carotene molecule.
Abstract 13006: Computed Tomographic Indexing Aortic Root Area to Height Provides Incremental Prognostic Utility in Patients With Trileaflet Aortic Valve and Dilated Aortic Root

Background: We sought to assess predictors of long-term outcomes in patients with dilated aortic roots, but with trileaflet aortic valves (TAV). We also sought to assess incremental prognostic utility of indexing aortic root area to height. Methods: We studied 584 consecutive patients (61±14 years, 89% men) with TAV & dilated aortic root (≥4 cm) that underwent echo & gated contrast-enhanced computed tomography (CT) of thoracic aorta between 2003-7. Clinical, echo & CT data were recorded. A ratio of aortic root area over height was calculated (cm2/m). A composite endpoint of death & dissection were recorded. Results: The mean Euroscore & ejection fraction were 9±5 & 55±9%; 7% had Marfan’s syndrome, 18% had ≥III+ aortic regurgitation (AR) & 3% had AV gradient ≥40 mm Hg. Aortic root sizes (on CT) were as follows: 4-4.5 cm (50%), 4.6-4.9 cm (28%), 5-5.5 cm (16%), >5.5 cm (6%). Aortic root area/height ratio was abnormal (≥10) in 27% patients. During a follow up of 4.6±4 years, 238 (41%) patients underwent ascending aortic surgery (+/- combination coronary bypass &/or AV replacement), while 104 (18%) met the composite endpoint (3% had an aortic dissection). On multivariable Cox Proportional Hazard Analysis, increasing age (Hazard ratio or HR 1.06), Marfan’s syndrome (HR 2.37), aortic root area/height ratio (HR 1.74) and aortic surgery (HR 0.86) were independently associated with composite endpoint (all p Conclusion: In TAV patients with dilated aortic root, ratio of aortic root area/height provides independent & improved stratification for prediction of death or dissection.
Physics education research: a model for introductory laboratory reform

During the 2002-2003 academic years a decision was made at American University to reform the introductory general education science classes by increasing the number of credit hours from 3 to 4. The intent of this reform effort was to add more substance to the introductory courses by increasing the laboratory experiences offered, and to make them comparable in credit hours to most introductory science courses around the country. As a result of this reform effort, the introductory physics classes were required to double the number of laboratory activities performed by the students during a given semester. The main objective behind increasing the number of laboratory activities was to increase the hands-on experiences of the students for the various topics covered within the curriculum. Through an internal grant award from American University, a significant amount of new laboratory equipment was purchased in spring 2003 and a number of new laboratory activities were created during the summer of 2003. The design and development of the new laboratory activities are described as they relate to current research in physics education. The research in this field has clearly shown that student learning can be enhanced through the use of content-specific, interactive engagement (IE) strategies. Tips regarding the choice of equipment for the introductory physics laboratory will also be shared. In addition, the overall reform effort within the introductory physics classes and laboratories are presented through a discussion of effective pedagogical strategies. The new laboratory activities were successfully piloted with over 100 students during the fail 2003 semester. This paper highlights student and instructor experiences with the new activities during the pilot semester. A description of the newly-created laboratory activities through the lens of current research in physics education should provide faculty teaching laboratory-based, introductory physics or engineering courses with some useful ideas and techniques for reforming or refreshing their own courses.
Androgen receptor signaling is required for androgen-sensitive human prostate cancer cell proliferation and survival

Androgens and androgen receptors (AR) regulate normal prostate development and growth. They also are involved in pathological development of prostatic diseases, including benign prostatic hyperplasia (BPH) and prostate cancer (PCa). Antiandrogen therapy for PCa, in conjunction with chemical or surgical castration, offers initial positive responses and leads to massive prostate cell death. However, cancer cells later appear as androgen-independent PCa. To investigate the role of AR in prostate cell proliferation and survival, we introduced a vector-based small interfering RNA (siRNA). This siRNA targeted 5'-untranslated region of AR mRNA for extended suppression of AR expression in androgen-sensitive human prostate LNCaP cells. The siRNA design successfully suppressed endogenous AR expression, as revealed by western blotting and immunofluorescence staining in LNCaP cells. LNCaP cells did not proliferate in the absence of AR and underwent apoptosis, based on elevated phospho-Histone H2B expression and higher number of apoptotic body as compared to control cells. We demonstrated that AR is vital for prostate cell proliferation and survival in this androgen-sensitive prostate cell line. These results further strengthen the hypothesis that AR can be a therapeutic target for treating androgen-sensitive stages of PCa. Unlike antiandorgens, however, siRNA targeting AR provides a direct inactivation of AR function through the suppression of AR protein expression.
BIS(Phthalocyaninato) Lanthanide Sandwich Compounds Exhibiting Mixed Valence Ligands

Bis(phthalocyaninato) lanthanide sandwich compounds have been synthesized for ytterbium and thulium. Low temperature magnetic susceptibility data suggest a strong antiferromagnetic interaction between the lanthanide f-electrons and the phthalocyaninato ligand radical electron.
Determination of heavy metals in environmental reference materials using solid sampling graphite furnace AAS

Cadmium and nickel are determined in Coal, Coal Fly Ash and Urban Particulate Matter Reference Materials using solid sampling graphite furnace AAS. The evaluation of integrated absorbance is required to overcome the effect of the matrix on the rate of atomization. The homogeneity of the samples under investigation in the range between 0.3 mg and 1.5 mg sample weight is good enough to make possible relative standard deviations around 10% for cadmium and between 10 and 20% for nickel. Cadmium can be determined against reference solutions, the nickel results are slightly lower than the certified value if calibration is performed against aqueous solutions. Calibration against a solid reference is therefore recommended. Less sensitive resonance lines and an internal gas flow through the tube are required for some of the samples to keep the absorbance in the linear calibration range. The direct determination of chromium in these samples is hampered by the lack of less sensitive resonance lines. Due to high concentrations of chromium in the samples, direct determination without dilution of the sample e.g. by spectrally pure graphite powder is impossible. The peak for the refractory carbide forming element vanadium is strongly suppressed by the Coal and the Urban Particulate matrix. Integration of the signal within a reasonable time and at an atomization temperature of 2650 °C is impossible.
All-systolic non-ECG-gated stress perfusion CMR: improved visualization of subendocardial defects compared to conventional ECG-gated imaging

Background The effects of ischemia are first realized in the subendocardium and progress transmurally. Hence, detection of the transmural extent of myocardial perfusion (MP) defects has important diagnostic/prognostic implications. Systolic MP imaging using ECG-gated methods has been shown to provide improved visualization of subendocardial defects [1]. We developed an innovative non-ECGgated perfusion CMR technique capable of imaging all slices at the same systolic phase, and hypothesized that it improves visualization of the transmural extent of MP defects compared to the conventional method in CMR studies of CAD patients.
The millimeter-wave spectrum of25MgNC and 26MgNC: bonding in magnesium isocyanides

Abstract Rotational spectra of the 25 Mg and 26 Mg isotopomers of MgNC have been recorded in the frequency range 298–386 GHz using millimeter/sub-millimeter direct absorption spectroscopy. The species were created in their natural isotopic ratios in a dc discharge of cyanogen gas and magnesium vapor. Rotational and fine structure parameters were determined for these radicals, as well as magnesium 25 hyperfine constants for 25 MgNC. For this isotopomer, b F ≈ −298(16), indicating a large electron density at the nucleus and an ionic type Mg + NC − structure, as expected for a linear configuration. R 0 bond lengths were also derived, which are in good agreement with theoretical calculations.
Thermodynamic characterization of interactions between p27Kip1 and activated and non-activated Cdk2: Intrinsically unstructured proteins as thermodynamic tethers

Abstract The cyclin-dependent kinase inhibitor (CKI) p27Kip1 plays a critical role in cell cycle regulation by binding and inhibiting (or activating) various cyclin-dependent kinase (Cdk)/cyclin complexes. Thermal denaturation monitored by circular dichroism (CD) and isothermal titration calorimetry (ITC) were used to determine the relative stabilities and affinities of p27-KID (p27 kinase inhibitory domain) complexes with activated Cdk2 (phosphorylated at Thr160; P-Cdk2) and non-activated forms of Cdk2 and/or cyclin A. Phosphorylation of residue Thr160 only slightly increases the thermal stability of Cdk2, and its binary complexes with cyclin A and p27-KID. The p27-KID/P-Cdk2/cyclin A or p27-KID/Cdk2/cyclin A ternary complexes exhibited significantly higher thermal stabilities compared to the binary complexes (P-Cdk2/cyclin A or Cdk2/cyclin A). Differences in Tm values between the binary and ternary complexes with P-Cdk2 and Cdk2 were + 25.9 and + 20.4 °C, respectively. These results indicate that the ternary complex with phosphorylated Cdk2 is stabilized to a larger extent than the non-phosphorylated complex. The free energy of association (ΔGA) for formation of the two ternary complexes was more favorable than for the binary complexes, indicating that a significantly smaller population of free components existed when all three components were present. These data indicate that p27-KID, which is intrinsically disordered in solution, acts as a thermodynamic tether when bound within the ternary complexes. It is proposed that thermodynamic tethering may be a general phenomena associated with intrinsically unstructured proteins (IUPs) which often function by binding to multiple partners in multi-protein assemblies.
Institutional morality, authority, and ethics committees: how far should respect for institutional morality go?

Virtually all persons who have had a hand in shaping the concept of ethics committees in this country accept the principle that the individuals making up the ethics committee should represent different interests, backgrounds, and viewpoints. In other words, ethics committees are intended mainly to represent the interests of the communities they serve. However, ethics committees often also serve hospitals that are religiously based and who, not unreasonably, may insist on affirming their own institutional morality and their own peculiar way of looking at some problems. Deep-seated ethical quandaries, especially in shaping policy, are often unavoidable.
Comparison of epigenetic profiles of human oral epithelial cells from HIV-positive (on HAART) and HIV-negative subjects

HIV-infected subjects on highly active antiretroviral therapy (HAART) are susceptible to comorbid microbial infections in the oral cavity. We observed that primary oral epithelial cells (POECs) isolated from HIV+ subjects on HAART grow more slowly and are less innate immune responsive to microbial challenge when compared with POECs from normal subjects. These aberrant cells also demonstrate epigenetic differences that include reduction in histone deacetylase 1 (HDAC-1) levels and reduced total DNA methyltransferase (DNMT) activity specific to enzymes DNMT1 and DNMT3A. The DNMT activity correlates well with global DNA methylation, indicating that aberrant DNMT activity in HIV+ (on HAART) POECs leads to an aberrantly methylated epithelial cell phenotype. Overall, our results lead us to hypothesize that, in patients with chronic HIV infection on HAART, epigenetic changes in key genes result in increased vulnerability to microbial infection in the oral cavity.
A Christian Understanding of Aesthetic Agency: A Theological Framework of Resistance to Cultural Imperialism

Aesthetic agency refers to conditions, capacities, and states that inform artistic forms of acting and exerting power on social structures. In resistance to the marginalization of women of color, aesthetic agency is exercised through creative acts of culture-making and critique of such practices to challenge domination and representation of the oppressed other. To support this work as a feminist Christian ethicist, I construct a theological framework for aesthetic agency. This paper proposes a theological understanding of transformative aesthetics and then describes the exercise of aesthetic agency for Christian communities by using a television special, Black Girls Rock! as an example. Racism, sexism, and oppression of minorities are ethical problems that assume varied forms. One form identified by Iris Marion Young as cultural imperialism is expressed through cultural forms that universalize a dominant group’s experience and make it the societal or cultural norm. (Welch 2008) Cultural imperialism concurrently stereotypes and marks a group as “other” while rendering the perspectives of those from inside the group as invisible. By perpetuating patterns of invisibility and aversion, cultural imperialism pushes minority groups to the margins of a culture. (Welch 2008) Stereotypes of women and people of color are communicated through society’s cultural forms: books, advertising, television, and artistic images. Yet, resources for resisting this marginalization can also assume cultural forms. Artworks and literature can be sites of resistance; galleries, museums, and schools can be spaces of opposition. The act of creating is self-affirming and when undertaken by marginalized peoples can be a source of empowerment to counter their mistreatment. In Art on My Mind: Visual Politics, bell hooks states, “It occurred to me then that if one could make a people lose touch with their capacity to create, lose sight of their will and their power to make art, then the work of subjugation, of colonization, is complete. Such work can only be undone by acts of concrete reclamation.” (Hooks 1995, xv) Hooks’ statement provokes consideration of how artistic and aesthetic practices can address the ethical problem of the marginalization of women of color in the United States. 1 Edwards: A Christian Understanding of Aesthetic Agency
DISCRETE CHOICE MODELS OF TRAVELER PARTICIPATION IN DIFFERENTIAL TIME OF DAY PRICING PROGRAMS

Abstract Tolls that vary based on time of day or congestion are gaining attention around the world as a potential travel demand management strategy that can shift peak period travel to off peak periods thereby contributing to peak period congestion relief. However, despite the widespread interest in the concept, there is very little empirical data available on the impacts of variable tolls on traveler choices and disaggregate models that can be used to predict traveler response to variable pricing are few. This paper reports on results from two bridges with differential time of day tolls in the Lee County area of Florida in the United States. Using travel survey data collected at these two bridges, discrete choice models of traveler response to the variable toll rates are estimated. The models indicate that travelers who are retired, have a low income, have flextime at their place of employment, or have a flexible travel schedule are more likely to alter their time of travel with greater frequency due to the variable toll.
Salvage photodynamic therapy for persistent esophageal cancer after chemoradiation therapy

Summary Background Locally advanced esophageal cancer may not be completely eradicated after chemoradiation therapy (CRT) and further treatment options are limited. Since 1998, we have used porfimer sodium photodynamic therapy (PDT) for inoperable patients with persistent mucosal carcinoma after CRT. Methods Seven patients have undergone PDT after CRT: median age 75 (range 68–85), four patients male, three patients female. After upper endoscopy with biopsies documented neoplasm after CRT, patients were evaluated with contrast-enhanced computed tomography of the chest and abdomen as well as endoscopic ultrasound to confirm persistence/recurrence of only mucosal disease. Results Two patients had squamous carcinoma while five patients had Barrett's adenocarcinoma (Barrett's median segment length = 8 cm; range 5–10 cm). PDT was performed after infusion of 2 mg/kg porfimer sodium using a median light dose of 150 J/cm (range 100–200) using the bare fiber method. After PDT, all patients developed strictures requiring dilation (median number of dilations required = 5, range 1–18). These patients have subsequently been followed with endoscopy every 3–6 months (mean follow up = 30 months, range 12–50 months). After an initial response, the two patients with squamous cell carcinoma have subsequently been found to have recurrent disease and are being treated with erlotinib. The other five patients treated for Barrett's carcinoma have remained disease free although one had died 33 months from metastatic colon cancer. Conclusion In selected patients, PDT may be useful in the treatment of persistent/recurrent mucosal esophageal cancer after incomplete response to CRT.
George F. Kennan : Cold War Iconoclast

This brilliant and eloquent book by a distinguished scholar and critic examines the history, the limits, and the promise of the human mind and the knowledge of which it is capable. Professor Highet explores the meaning of our culture from the intellectual and moral monuments of the Greeks, Romans, and Judeo-Christians, and our contemporary thinkers. Out of this book comes a clear definition of knowledge and insights into the strength and limitations of the mind.
Structure-activity relationships and cancer-cell selective toxicity of novel inhibitors of glioma-associated oncogene homologue 1 (Gli1) mediated transcription.

We report novel inhibitors of Gli1-mediated transcription as potential anticancer agents. Focused chemical libraries were designed and assessed for inhibition of functional cell-based Gli1-mediated transcription and selective toxicity toward cancer cells. The SAR was revealed, and the selectivity of the lead compounds’ inhibition of Gli1-mediated transcription over that of Gli2 was determined. Compound 63 (NMDA298-1), which inhibited Gli1-mediated transcription in C3H10T1/2 cells with an IC50 of 6.9 μM, showed 3-fold selectivity for inhibiting transcription mediated by Gli1 over that by Gli2. Cell-viability assays were performed to evaluate the chemical library in a normal cell line and a panel of cancer cell lines with or without up-regulated expression of the Gli1 gene. These compounds decreased the viability of several cancer cell lines but were less active in the noncancerous BJ-hTERT cells.
Assessment of Humanistic, Transpersonal, and Spiritual Constructs: State of the Science

This article reports on the current status of psychometric testing as it pertains to the measurement and assessment of constructs relevant to humanistic and transpersonal psychologies. In so doing,...
Random DFA's can be approximately learned from sparse uniform examples

Approximate inference of finite state machines from sparse labeled examples has been proved NP-hard when an adversary chooses the target machine and the training set [Ang78, KV89, PW89]. We have, however, empirically found that DFA's are approximately learnable from sparse data when the target machine and training set are selected at random.