cssi/SciSciGPT-SciSciNet huggingface dataset:
Estradiol Influences Adenosinergic Signaling and NREM Sleep Need in Adult Female Rats.

Gonadal steroids and gender are risk factors for sleep disruptions and insomnia in women. However, the relationship between ovarian steroids and sleep is poorly understood. In rodent models, estradiol (E2) suppresses sleep in females suggesting that E2 may reduce homeostatic sleep need. The current study investigates whether E2 decreases sleep need and the potential mechanisms that govern E2 suppression of sleep. Our previous findings suggest that the median preoptic nucleus (MnPO) is a key nexus for E2 action on sleep. Using behavioral, neurochemical and pharmacological approaches, we tested whether (1) E2 influenced the sleep homeostat and (2) E2 influenced adenosine signaling in the MnPO of adult female rats. In both unrestricted baseline sleep and recovery sleep from 6-hour sleep deprivation, E2 significantly reduced non-rapid eye movement sleep (NREM)-delta power, NREM-Slow Wave Activity (NREM-SWA, 0.5-4.0Hz), and NREM-delta energy suggesting that E2 decreases homeostatic sleep need. However, coordinate with E2-induced changes in physiological markers of homeostatic sleep was a marked increase in MnPO extracellular adenosine (a molecular marker of homeostatic sleep need) during unrestricted and recovery sleep in E2-treated but not oil control animals. While these results seemed contradictory, systemically administered E2 blocked the ability of CGS-21680 (adenosine A2A receptor agonist) microinjected into the MnPO to increase NREM sleep suggesting that E2 may block adenosine signaling. Together, these findings provide evidence that E2 may attenuate the local effects of the A2A receptors in the MnPO which in turn may underlie estrogenic suppression of sleep behavior as well as changes in homeostatic sleep need.
The Age of Gossip in Networks

A source node updates its status as a point process and also forwards its updates to a network of observer nodes. Within the network of observers, these updates are forwarded as point processes from node to node. Each node wishes its knowledge of the source to be as timely as possible. In this network, timeliness is measured by a discrete form of age of information: each status change at the source is referred to as a version and the age at a node is how many versions out of date is its most recent update from the source. This work introduces a method for evaluating the average version age at each node in the network when nodes forward updates using a memoryless gossip protocol. This method is then demonstrated by version age analysis for a collection of simple networks. For gossip on a complete graph with symmetric updating rates, it is shown that each node has average age that grows as the logarithm of the network size.
Recommender system of scholarly papers using public datasets

The exponential growth of public datasets in the era of Big Data demands new solutions for making these resources findable and reusable. Therefore, a scholarly recommender system for public datasets is an important tool in the field of information filtering. It will aid scholars in identifying prior and related literature to datasets, saving their time, as well as enhance the datasets reusability. In this work, we developed a scholarly recommendation system that recommends research-papers, from PubMed, relevant to public datasets, from Gene Expression Omnibus (GEO). Different techniques for representing textual data are employed and compared in this work. Our results show that term-frequency based methods (BM25 and TF-IDF) outperformed all others including popular Natural Language Processing embedding models such as doc2vec, ELMo and BERT.
Unsupervised selection of optimal single-molecule time series idealization criterion.

Abstract Single-molecule (SM) approaches have provided valuable mechanistic information on many biophysical systems. As technological advances lead to ever-larger datasets, tools for rapid analysis and identification of molecules exhibiting the behavior of interest are increasingly important. In many cases the underlying mechanism is unknown, making unsupervised techniques desirable. The Divisive Segmentation and Clustering (DISC) algorithm is one such unsupervised method that idealizes noisy SM time series much faster than computationally intensive approaches without sacrificing accuracy. However, DISC relies on a user selected objective criterion (OC) to guide its estimation of the ideal time series. Here, we explore how different OCs affect DISC's performance for data typical of SM fluorescence imaging experiments. We find that OCs differing in their penalty for model complexity each optimize DISC's performance for time series with different properties such as signal-to-noise and number of sample points. Using a machine learning approach, we generate a decision boundary that allows unsupervised selection of OC based on the input time series to maximize performance for different types of data. This is particularly relevant for SM fluorescence datasets which often have signal-to-noise near the derived decision boundary and include time series of nonuniform length due to stochastic bleaching. Our approach, AutoDISC, allows unsupervised per-molecule optimization of DISC, which will substantially assist in the rapid analysis of high-throughput single-molecule datasets with noisy samples and nonuniform time windows.
Considerations for Neuromorphic Supercomputing in Semiconducting and Superconducting Optoelectronic Hardware.

Any large-scale spiking neuromorphic system striving for complexity at the level of the human brain and beyond will need to be co-optimized for communication and computation. Such reasoning leads to the proposal for optoelectronic neuromorphic platforms that leverage the complementary properties of optics and electronics. Starting from the conjecture that future large-scale neuromorphic systems will utilize integrated photonics and fiber optics for communication in conjunction with analog electronics for computation, we consider two possible paths towards achieving this vision. The first is a semiconductor platform based on analog CMOS circuits and waveguide-integrated photodiodes. The second is a superconducting approach that utilizes Josephson junctions and waveguide-integrated superconducting single-photon detectors. We discuss available devices, assess scaling potential, and provide a list of key metrics and demonstrations for each platform. Both platforms hold potential, but their development will diverge in important respects. Semiconductor systems benefit from a robust fabrication ecosystem and can build on extensive progress made in purely electronic neuromorphic computing but will require III-V light source integration with electronics at an unprecedented scale, further advances in ultra-low capacitance photodiodes, and success from emerging memory technologies. Superconducting systems place near theoretically minimum burdens on light sources (a tremendous boon to one of the most speculative aspects of either platform) and provide new opportunities for integrated, high-endurance synaptic memory. However, superconducting optoelectronic systems will also contend with interfacing low-voltage electronic circuits to semiconductor light sources, the serial biasing of superconducting devices on an unprecedented scale, a less mature fabrication ecosystem, and cryogenic infrastructure.
NavStick: Making Video Games Blind-Accessible via the Ability to Look Around

Video games remain largely inaccessible to visually impaired people (VIPs). Today’s blind-accessible games are highly simplified renditions of what sighted players enjoy, and they do not give VIPs the same freedom to look around and explore game worlds on their own terms. In this work, we introduce NavStick, an audio-based tool for looking around within virtual environments, with the aim of making 3D adventure video games more blind-accessible. NavStick repurposes a game controller’s thumbstick to allow VIPs to survey what is around them via line-of-sight. In a user study, we compare NavStick with traditional menu-based surveying for different navigation tasks and find that VIPs were able to form more accurate mental maps of their environment with NavStick than with menu-based surveying. In an additional exploratory study, we investigate NavStick in the context of a representative 3D adventure game. Our findings reveal several implications for blind-accessible games, and we close by discussing these.
The risk-return relation puzzle

Abstract A positive stock market variance-return relation is the key building block of extant rational-expectations asset pricing models. Empirical evidence is elusive despite forty years of intensive academic research. The conjecture is also resoundingly refuted by the late 1990s' dotcom bubble featured by sharp increases in both market prices and variance. Gao and Martin (2021) , Lochstoer and Muir (2021) , and Nagel and Xu (2021) interpret empirical findings as evidence of irrational expectations. Ai, Han, and Xu (2021) attribute the weak or negative risk-return relation to learning about economic fundamentals with imperfect signals. Guo, Lin, and Pai (2021) argue for two types of fundamental variance that have opposite effects on conditional equity premium and market prices. More research is needed to explain the risk-return relation puzzle prevalent in both U.S. and Asia-Pacific markets.
Towards a conjecture of Pappas and Rapoport on a scheme attached to the symplectic group

Let n = 2r be an even integer. We consider a closed subscheme V of the scheme of n-by-n skew-symmetric matrices, on which there is a natural action of the symplectic group Sp(n). Over a field F of characteristic not equal to 2, the scheme V is isomorphic to the scheme appeared in a conjecture by Pappas and Rapoport on local models of unitary Shimura varieties. With the additional assumption char F = 0 or char F > r, we prove the coordinate ring of V has a basis consisting of products of pfaffians labelled by King's symplectic standard tableaux with no odd-sized rows. When n is a multiple of 4, the basis can be used to show that the coordinate ring of V is an integral domain, and this proves a special case of the conjecture by Pappas and Rapoport.
Averaging over moduli in deformed WZW models

WZW models live on a moduli space parameterized by current-current deformations. The moduli space defines an ensemble of conformal field theories, which generically have N abelian conserved currents and central charge c > N. We calculate the average partition function and show that it can be interpreted as a sum over 3-manifolds. This suggests that the ensemble-averaged theory has a holographic dual, generalizing recent results on Narain CFTs. The bulk theory, at the perturbative level, is identified as U(1)2N Chern-Simons theory coupled to additional matter fields. From a mathematical perspective, our principal result is a Siegel-Weil formula for the characters of an affine Lie algebra.
DIP: Natural history model for major depression with incidence and prevalence.

Abstract Background Major depression is a treatable disease, and untreated depression can lead to serious health complications. Therefore, prevention, early identification, and treatment efforts are essential. Natural history models can be utilized to make informed decisions about interventions and treatments of major depression. Methods We propose a natural history model of major depression. We use steady-state analysis to study the discrete-time Markov chain model. For this purpose, we solved the system of linear equations and tested the parameter and transition probabilities empirically. Results We showed that bias in parameters might collectively cause a significant mismatch in a model. If incidence is correct, then lifetime prevalence is 33.2% for females and 20.5% for males, which is higher than reported values. If prevalence is correct, then incidence is .0008 for females and .00065 for males, which is lower than reported values. The model can achieve feasibility if incidence is at low levels and recall bias of the lifetime prevalence is quantified to be 31.9% for females and 16.3% for males. Limitations This model is limited to major depression, and patients who have other types of depression are assumed healthy. We assume that transition probabilities (except incidence rates) are correct. Conclusion We constructed a preliminary model for the natural history of major depression. We determined the lifetime prevalences are underestimated and the average incidence rates may be underestimated for males. We conclude that recall bias needs to be accounted for in modeling or burden estimates, where the recall bias should increase with age.
Full spectrum optical constant interface to the Materials Project

Abstract Optical constants characterize the interaction of materials with light and are important properties in material design. Here we present a Python-based Corvus workflow for simulations of full spectrum optical constants from the visible and ultraviolet to hard x-ray wavelengths based on the real-space Green’s function code FEFF10 and structural data from the Materials Project (MP). The Corvus workflow manager and its associated tools provide an interface to FEFF10 and the MP database. The workflow parallelizes the FEFF computations of optical constants over all absorption edges for each material in the MP database specified by a unique MP-ID. The workflow tools determine the distribution of computational resources needed for that case. Similarly, the optical constants for selected sets of materials can be computed in a single-shot. To illustrate the approach, we present results for several elemental solids in the periodic table, as well as a sample compound, and compare our predictions with experimental results. In addition, we provide a database of calculated results for all elements for which there is a stable elemental solid at standard conditions available in the Materials Project database. As in x-ray absorption spectra, these results are interpreted in terms of an atomic-like background and fine-structure contributions.
Unsupervised Machine Learning for Unbiased Chemical Classification in X-ray Absorption Spectroscopy and X-ray Emission Spectroscopy

We report a comprehensive computational study of unsupervised machine learning for extraction of chemically relevant information in X-ray absorption near edge structure (XANES) and in valence-to-core X-ray emission spectra (VtC-XES) for classification of a broad ensemble of sulphorganic molecules. By progressively decreasing the constraining assumptions of the unsupervised machine learning algorithm, moving from principal component analysis (PCA) to a variational autoencoder (VAE) to t-distributed stochastic neighbour embedding (t-SNE), we find improved sensitivity to steadily more refined chemical information. Surprisingly, when embedding the ensemble of spectra in merely two dimensions, t-SNE distinguishes not just oxidation state and general sulphur bonding environment but also the aromaticity of the bonding radical group with 87% accuracy as well as identifying even finer details in electronic structure within aromatic or aliphatic sub-classes. We find that the chemical information in XANES and VtC-XES is very similar in character and content, although they unexpectedly have different sensitivity within a given molecular class. We also discuss likely benefits from further effort with unsupervised machine learning and from the interplay between supervised and unsupervised machine learning for X-ray spectroscopies. Our overall results, i.e., the ability to reliably classify without user bias and to discover unexpected chemical signatures for XANES and VtC-XES, likely generalize to other systems as well as to other one-dimensional chemical spectroscopies.
Neural ranking models for document retrieval

Ranking models are the main components of information retrieval systems. Several approaches to ranking are based on traditional machine learning algorithms using a set of hand-crafted features. Recently, researchers have leveraged deep learning models in information retrieval. These models are trained end-to-end to extract features from the raw data for ranking tasks, so that they overcome the limitations of hand-crafted features. A variety of deep learning models have been proposed, and each model presents a set of neural network components to extract features that are used for ranking. In this paper, we compare the proposed models in the literature along different dimensions in order to understand the major contributions and limitations of each model. In our discussion of the literature, we analyze the promising neural components, and propose future research directions. We also show the analogy between document retrieval and other retrieval tasks where the items to be ranked are structured documents, answers, images and videos.
Cohmeleon: Learning-Based Orchestration of Accelerator Coherence in Heterogeneous SoCs

One of the most critical aspects of integrating loosely-coupled accelerators in heterogeneous SoC architectures is orchestrating their interactions with the memory hierarchy, especially in terms of navigating the various cache-coherence options: from accelerators accessing off-chip memory directly, bypassing the cache hierarchy, to accelerators having their own private cache. By running real-size applications on FPGA-based prototypes of many-accelerator multi-core SoCs, we show that the best cache-coherence mode for a given accelerator varies at runtime, depending on the accelerator’s characteristics, the workload size, and the overall SoC status. Cohmeleon applies reinforcement learning to select the best coherence mode for each accelerator dynamically at runtime, as opposed to statically at design time. It makes these selections adaptively, by continuously observing the system and measuring its performance. Cohmeleon is accelerator-agnostic, architecture-independent, and it requires minimal hardware support. Cohmeleon is also transparent to application programmers and has a negligible software overhead. FPGA-based experiments show that our runtime approach offers, on average, a 38% speedup with a 66% reduction of off-chip memory accesses compared to state-of-the-art design-time approaches. Moreover, it can match runtime solutions that are manually tuned for the target architecture.
Areeda, Chicago, and Antitrust Injury: Economic Efficiency and Legal Process

This article, published in 1986, compares and contrasts the Chicago School's conceptual approach to antitrust issues with Phillip Areeda's legal process (or "Harvard School") approach. The study focuses on the antitrust injury doctrine, but it reveals the fundamental characteristics of the two schools, both of which have deeply influenced the evolution of U.S. antitrust law.
Computer Bounds for Kronheimer–Mrowka Foam Evaluation

Kronheimer and Mrowka recently suggested a possible approach towards a new proof of the four color theorem that does not rely on computer calculations. Their approach is based on a functor $J^\sharp$, which they define using gauge theory, from the category of webs and foams to the category of vector spaces over the field of two elements. They also consider a possible combinatorial replacement $J^\flat$ for $J^\sharp$. Of particular interest is the relationship between the dimension of $J^\flat(K)$ for a web $K$ and the number of Tait colorings $\mathrm{Tait}(K)$ of $K$; these two numbers are known to be identical for a special class of "reducible" webs, but whether this is the case for nonreducible webs is not known. We describe a computer program that strongly constrains the possibilities for the dimension and graded dimension of $J^\flat(K)$ for a given web $K$, in some cases determining these quantities uniquely. We present results for a number of nonreducible example webs. For the dodecahedral web $W_1$ the number of Tait colorings is $\mathrm{Tait}(W_1) = 60$, but our results suggest that $\dim J^\flat(W_1) = 58$.
Understanding the Impact of Driver’s License Suspension: Lay Opinion in Impacted and Non-Impacted Populations

The impact of low-level criminal enforcement on communities has been the subject of a growing body of scholarship and policy work, and awareness that even minor offenses can impose unaffordable cri...
In-Hardware Learning of Multilayer Spiking Neural Networks on a Neuromorphic Processor

Although widely used in machine learning, backpropagation cannot directly be applied to SNN training and is not feasible on a neuromorphic processor that emulates biological neuron and synapses. This work presents a spike-based backpropagation algorithm with biological plausible local update rules and adapts it to fit the constraint in a neuromorphic hardware. The algorithm is implemented on Intel’s Loihi chip enabling low power in-hardware supervised online learning of multilayered SNNs for mobile applications. We test this implementation on MNIST, Fashion-MNIST, CIFAR-10 and MSTAR datasets with promising performance and energy-efficiency, and demonstrate a possibility of incremental online learning with the implementation.
Forgotten at Guantanamo: The Boumediene Decision and Its Implications for Refugees at the Base under the Obama Administration

On January 22, 2009, newly inaugurated President Barack Obama signed an Executive Order calling for the closure of Guantanamo Bay Naval Base in response to longstanding criticisms of the Bush Administration‘s Guantanamo policy. 1 The Order requires review of detention and prompt disposition of all cases involving Guantanamo detainees. It was meticulously drafted to apply to all ―individuals currently detained by the Department of Defense in facilities at the Guantanamo Bay Naval Base whom the Department of Defense has ever determined to be, or treated as, enemy combatants.‖ 2 The Order attempts to bring U.S. policy into compliance with both international law and domestic law, invoking the detainee protections of both the Geneva Conventions and U.S. domestic law. 3 It also acknowledges the momentous 2008 decision Boumediene v. Bush, in which the Supreme Court held that the right to constitutional habeas extends to alleged enemy combatant detainees at Guantanamo, and that it does so by virtue of de facto U.S. sovereignty over the territory. 4
New Wheats and Social Progress.

Will the upward trend in all food production, so dramatically exemplified by the new wheats, be adequate to meet the needs of the growing population? Yes, for a while. No one knows for how long (14). The prophets of doom will undeniably be proved right in the long run unless their basic assumptions are nullified by concrete acts, and soon. At some point in time, either a zero population growth must be achieved or vast new sources of food must be developed, and purchasing power increased. There is nothing on the research horizon to reject "a prodigious need for mankind to practice human husbandry" (12). Our waste products have reached levels that cause major concern, and it may well be that both agricultural and social advancement will be halted by the demands dictated by population growth and the by-products of what now passes for progress but also brings environmental unbalance (15). At least, life will be different, and it may be catastrophic (16, 28). The "Three Ancients" (29) who helped plan and then, after a quarter of a century, reviewed the agricultural research and development work of the Rockefeller Foundation in developing nations concluded:
THE COST OF TRANSPORTATION IN PRE-INDUSTRIAL EUROPE*

In pre-industrial Europe, rising productivity both in agriculture and in industry depended on the expansion of trade, and the expansion of trade depended in turn on the reduction of trading costs. An important component of trading costs—for some goods the most important—was the cost of transportation. This had two elements: the cost of predation and the cost of carriage. This paper examines these two elements and how they changed over time. It also discusses the relative importance in lowering the cost of transportation of organizational change and technological progress.
SUPEROXIDE PRODUCTION BY PHAGOCYTOSING MACROPHAGES IN RELATION TO THE INTRACELLULAR DISTRIBUTION OF OXYGEN

We simultaneously measured the con- centration of oxygen ((O2)) within the phagosomal and extracellular compartments of macrophages. By combining electron paramagnetic resonance (EPR) oximetry techniques with that of spin- trapping, we found that a significant difference in oxygen concentration ((O2)) exists between these two compartments and we were able to monitor (1) how (O2) in the extracellular compartment and the rate of mitochondrial consumption affected this difference in (O2), and (2) to what extent this gradient of (O2) influenced production of reactive oxygen species by phagosomes. Under conditions where the (O2) in the inflowing gas was high (210 mM; air), the (O2) in the extracellular and phago- somal compartments was 180 and 141 mM, respec- tively. This was sufficient to maintain maximum superoxide production in these cells. When extra- cellular (O2) was reduced to 84 or 36 mM, the (O2) in phagosomes within the cells (31.7 and 7.7 mM, respectively) was too low to maintain superoxide production by the NADPH-oxidase system within the phagosomes. The (O2) in the extracellular compartments of these samples, however, was al- ways sufficient to maintain superoxide production by phagosomes at the cell surface. Our findings suggest that the distribution of oxygen surrounding and within macrophages can influence their ability to perform microbicidal and tumoricidal functions, even at an (O2) in the media that appears to be adequate. J. Leukoc. Biol. 64: 78-84; 1998.
A Case Study: The Indirect Aerosol Effects of Mineral Dust on Warm Clouds

Abstract The indirect aerosol effect (Twomey effect) is studied during a Saharan dust-transport event that presented an unusually favorable combination of a dust-loading gradient across clouds with warm cloud-top temperatures. Standard retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E), and the Clouds and the Earth’s Radiant Energy System (CERES) provide cloud-top temperature (a surrogate for height), liquid water path (LWP), classification of precipitation regime, and radiation flux. The authors correlate a retrieved mean effective droplet radius (re) versus the number concentration of cloud condensation nuclei (NCCN), using the regressed slope d lnre/d lnNCCN as the estimator of the aerosol indirect effect (AIE). Results demonstrate statistically significant AIE for only some of the segregated cloud classes. For nonprecipitating clouds (the most direct test of Twomey effect), the estimated AIE is effec...
Movement without mobility: Adolescent status hierarchies and the contextual limits of cumulative advantage

This paper develops a theory of interpersonal status hierarchies that builds on and challenges traditional models of cumulative advantage. Cumulative advantage models predict stability in interpersonal status hierarchies, where status is defined by asymmetries in social relationships. According to strict cumulative advantage, initial status differences are exaggerated over time, making upward or downward mobility unlikely. We argue that interpersonal status hierarchies are instead quite fluid, with individuals regularly moving up or down the hierarchy. Individual status gains do not, however, disrupt the status order as the upwardly mobile are often pulled back to their original positions. This drag of the past generates the same long run status outcomes as cumulative advantage models, but through very different means: sustained upward mobility is rare because the upwardly mobile fail to maintain their status gains, and not because initial gains are impossible. More generally, the effect of the past limits sustained mobility in most, but not all, status hierarchies, and we expect sustained mobility where ties are stable and the expectations for reciprocity are low. We test our model using longitudinal data on adolescents, finding strong support for the theory. We end the paper with a reflexive discussion about measurement error, hypothesis testing, and “messy” longitudinal network data.
Influence of viscosity on the reflection and transmission of an acoustic wave by a periodic array of screens. The general 3-D problem.

An analysis is presented of the diffraction of a pressure wave by a periodic grating including the influence of the air viscosity. The direction of the incoming pressure wave is arbitrary. As opposed to the classical nonviscous case, the problem cannot be reduced to a plane problem having a definite 3-D character. The system of partial differential equations used for solving the problem consists of the compressible Navier-Stokes equations associated with no-slip boundary conditions on solid surfaces. The problem is reduced to a system of two hypersingular integral equations for determining the velocity components in the slits’ plane and a hypersingular integral equation for the normal component of velocity. These equations are solved by using Galerkin’s method with some special trial functions. The results can be applied in designing protective screens for miniature microphones realized in MEMS technology. In this case, the physical dimensions of the device are on the order of the viscous boundary layer so that the viscosity cannot be neglected. The analysis indicates that the openings in the screen should be on the order of 10 microns in order to avoid excessive attenuation of the signal. This paper also provides the variation of the transmission coefficient with frequency in the acoustical domain.
MLK4β functions as a negative regulator of MAPK signaling and cell invasion

Mixed lineage kinase (MLK) 4, or MLK4, is a member of the MLK family of mitogen-activated protein kinase kinase kinases (MAP3Ks). Typically, MAP3Ks function to activate the mitogen-activated protein kinase (MAPK)-signaling pathways and regulate different cellular responses. However, here we report that MLK4β, unlike the other MLKs, negatively regulates the activities of the MAPKs, p38, c-Jun N-terminal kinase and extracellular signal-regulated kinase, and the MAP2Ks, MEK3 and 6. Our results show that MLK4β inhibits sorbitol- and tumor necrosis factor-induced activation of p38. Furthermore, MLK4β interacts with another MLK family member, MLK3, in HCT116 cells. Exogenous expression of MLK4β inhibits activation of MLK3 and also blocks matrix metalloproteinase-9 gelatinase activity and invasion in SKOV3 ovarian cancer cells. Collectively, our data establish MLK4β as a novel suppressor of MLK3 activation, MAPK signaling and cell invasion.
The principle of maximum hardness and structural effects of nonbonded interactions in chloronitromethanes

Abstract The three monochloronitromethanes encompass a variety of possible nonbonded intramolecular interactions, both attractive (Cl- - -O, N- - -O and H- - -O) and repulsive (O- - -O). These are responsible for the different NO2 orientations as well as the marked shortening of the C–Cl bond. We have investigated computationally the effectiveness of the principle of maximum hardness as a means of predicting the C–Cl bond lengths and Cl–C–N–O dihedral angles in the chloronitromethanes. The B3PW91/6-31G(d,p) procedure was used, and the hardness was determined from the energies of the highest and lowest occupied molecular orbitals. It was concluded that the maximum hardness principle is a reasonably good guide to the most stable conformations of these molecules, but less satisfactory with respect to the C–Cl distance.
Radiographic evaluation of stillbirth: What does it contribute?

Despite advances in perinatal care, stillbirth is relatively common (1/160 births) and frequently remains unexplained. Most recent protocols for etiologic evaluation of stillbirth either omit radiography or reserve it for infants with obvious skeletal disproportion. Over the past 30 years, the Wisconsin Stillbirth Service Program has collected radiographic images from 2,032 stillbirths and second trimester losses, of which about 25% (517) showed abnormalities. Review of these images by a medical geneticist showed that radiographs yielded a diagnosis in 45% of the infants with abnormalities (11.5% of all radiographs obtained) and were critical, yielding a diagnosis that would otherwise have been missed or incomplete in 1.5% of the total infants. The probability of a diagnosis was not significantly different between miscarriages <20 weeks and stillbirths. Diagnoses were mainly fetal, most commonly sporadic birth defects, idiopathic hydrops, chromosome abnormalities, and skeletal dysplasias, but chorioamnionitis with fetal sepsis, complications of twinning, and cord accidents were also diagnosed radiographically. Radiographs may help direct the use of newer technologies such as chromosomal microarray or gene sequencing. Limiting radiographs to infants with obvious skeletal disproportion would have resulted in many of these diagnoses, including 4/24 skeletal dysplasias, being overlooked. We recommend at least an anterior/posterior babygram film as part of the permanent record of all second trimester losses and stillbirths.
Centralspindlin and Chromosomal Passenger Complex Behavior During Normal and Rappaport Furrow Specification in Echinoderm Embryos

The chromosomal passenger (CPC) and Centralspindlin complexes are essential for organizing the anaphase central spindle and providing cues that position the cytokinetic furrow between daughter nuclei. However, echinoderm zygotes are also capable of forming “Rappaport furrows” between asters positioned back-to-back without intervening chromosomes. To understand how these complexes contribute to normal and Rappaport furrow formation, we studied the localization patterns of Survivin and mitotic-kinesin-like-protein1 (MKLP1), members respectively of the CPC and the Centralspindlin complex, and the effect of CPC inhibition on cleavage in mono- and binucleate echinoderm zygotes. In zygotes, Survivin initially localized to metaphase chromosomes, upon anaphase onset relocalized to the central spindle and then, together with MKLP1 spread towards the equatorial cortex in an Aurora-dependent manner. Inhibition of Aurora kinase activity resulted in disruption of central spindle organization and furrow regression, although astral microtubule elongation and furrow initiation were normal. In binucleate cells containing two parallel spindles MKLP1 and Survivin localized to the plane of the former metaphase plate, but were not observed in the secondary cleavage plane formed between unrelated spindle poles, except when chromosomes were abnormally present there. However, the secondary furrow was sensitive to Aurora inhibition, indicating that Aurora kinase may still contribute to furrow ingression without chromosomes nearby. Our results provide insights that reconcile classic micromanipulation studies with current molecular understanding of furrow specification in animal cells.
NOAA's status and trends mussel watch program: Chlorinated pesticides and PCBs in oysters (Crassostrea virginica) and sediments from the Gulf of Mexico, 1986–1987

Abstract Chlorinated pesticides and PCBs were analyzed in more than 590 oyster and sediment samples collected during 1986 and 1987, the first 2 years of the NOAA's Status and Trends Mussel Watch Program established to monitor the current status and temporal trends of these contaminants in the Gulf of Mexico. Chlorinated hydrocarbons in oysters and sediments presented similar distribution patterns; however, their concentrations in oysters were several times higher than the concentration detected in the surrounding sediments. Alpha-chlordane, trans -nonachlor and dieldrin were the most abundant non-DDT pesticides in both types of sample. The major fraction of DDT related compounds measured in oysters and sediments was DDD. Based on average PCB concentrations, penta-, hexa-, and tetrachlorobiphenyls were preferentially accumulated by oysters as compared to the average sediment composition. Although this study was designed to avoid known point-sources of contaminant inputs, the measured concentrations were, in general, within the range of concentrations previously reported for the Gulf of Mexico. After the first 2 years of this program, the geographical distribution of chlorinated hydrocarbons in oysters and sediments is well defined. In contrast, the temporal trends at the different sites are not clear. Continued sampling will allow the identification of long-term trends in concentrations of chlorinated hydrocarbons in the Gulf of Mexico.
Continuous spectrophotometric assay for ascorbate oxidase based on a novel chromophoric substrate, 2-aminoascorbic acid.

Recently, we reported the development of a sensitive continuous spectrophotometric assay for the ascorbate-dependent mammalian enzyme dopamine beta-monooxygenase based on the novel chromophoric electron donor 2-aminoascorbic acid [K. Wimalasena and D.S. Wimalasena (1991) Anal. Biochem. 197, 353-361]. We now report that ascorbate oxidase (EC 1.10.3.3, L-ascorbate:O2 oxidoreductase) also catalyzes the oxidation of 2-aminoascorbic acid to chromophoric 2,2'-nitrilodi-2(2')-deoxy-L-ascorbic acid (red pigment). The reaction is kinetically well behaved, displaying the expected stoichiometry for an oxidase-catalyzed reaction with respect to oxygen and the oxidation product (red pigment), demonstrating that 2-aminoascorbic acid is a well-behaved alternative substrate for the enzyme. Ascorbate oxidase is a very efficient enzyme toward its natural substrate, ascorbic acid. Although 2-amino-ascorbic acid is a significantly weak substrate for the enzyme in comparison to ascorbic acid, as indicated by the apparent initial rate kinetic parameters, the high extinction coefficient of the red pigment under our assay conditions suggests that this novel reactivity of the enzyme could be used to design a sensitive, convenient, and continuous spectrophotometric assay for ascorbate oxidase. While this assay is more convenient than the existing oxygen monitor assay, its adaptability to measure the activity of the enzyme in the immobilized form may be helpful in the development of technologies for the automated detection of ascorbic acid in biological fluids for industrial or clinical applications. In addition, this novel reactivity of the enzyme may be used to examine the substrate specificity and the mechanism of action of the enzyme.
Solid-vapour equilibria research on systems of interest in cryogenics

Abstract A review of research associated with solid-vapour equilibria of cryogenic systems is given with emphasis on the fundamental value of such studies. Included are discussions of vapour pressures of solidified fluids, theory applicable to the prediction of solid-vapour equilibria, available data in the solid-vapour region for systems of cryogenic interest, and a correlation derived from selected solid-vapour equilibria data, which is offered as a significant improvement in the prediction of properties of two-component systems in general.
Coherence in Cartesian squares

Abstract The primary object under consideration is a ring, A, which can be written as a particular type of fiber-product of two other rings. The objective is to ascend properties of the components of A to A itself. The paper concerns itself by and large with the notions of coherence, global dimension, and Tor dimension. Several applications are given.
Scrotal swelling: Unusual first presentation of Crohn's disease

Crohn's disease often is detected in adolescents with nonspecific gastrointestinal complaints. Extraintestinal complications are common but usually follow the onset of the bowel complaints. We present an unusual case in which scrotal swelling was the first symptom in a patient discovered to have Crohn's disease.
ToF-SIMS imaging with cluster ion beams

Molecule-specific imaging using focused ion beams is one of the most powerful applications of ToF-SIMS and offers unique surface characterization information. However, many experiments lack the necessary sensitivity to properly take advantage of the sub-100 nm probe size typical of liquid metal ion sources. The yield of biomolecules using Ga + ions, for example, is very small when compared to that obtained using Cs + ion or SF 5 + cluster ion sources. Most recently, a C 60 + source with a probe size approaching 1 x 10 -6 m has become available and offers promise to expand imaging applications dramatically. Here, we report on imaging experiments on 50×10 -6 m polystyrene resin particles used in solid phase synthesis of combinatorial libraries and on the assay of the membrane chemistry of single biological cells. Both of these examples allow much higher quality images to be acquired with, in some cases, almost no sample damage. This latter effect opens the possibility of three-dimensional molecule-specific imaging.
Dispersion of ensembles of non-interacting particles

The dynamics of an ensemble of particles emanating from a common point with a distribution of velocities is modeled as a continuum of particles described by a phase space distribution function. A general solution for the distribution function and the associated spatial density function is obtained for a general dynamical system. The special cases of linear dynamical systems and slow dispersion from a circular orbit are treated in detail. A transcendental equation is derived, the roots of which determine the time since initial dispersion from knowledge of the spatial density function at later times.
Effect of tidal cycle and food intake on the baseline plasma corticosterone rhythm in intertidally foraging marine iguanas

In most species, plasma levels of baseline glucocorticoids such as corticosterone (B) have a circadian rhythm. This rhythm can be entrained by both photoperiod and food intake and is related to aspects of energy intake and metabolism. Marine iguanas (Amblyrhynchus cristatus) offer a unique opportunity to better understand the relative importance of the light:dark cycle versus food intake in influencing the rhythm in baseline B in a natural system. Compared to other species, food intake is not as strictly determined by the phase of the light:dark cycle. Animals feed in the intertidal zone so feeding activity is heavily influenced by the tidal cycle. We measured baseline plasma B levels in free-living iguanas over several 24-h periods that varied in the timing of low tide/foraging activity. We found that baseline B levels were higher during the day relative to night. However, when low tide occurred during the day, baseline B levels dropped coincident with the timing of low tide. Whether the baseline B rhythm (including the drop during foraging) is an endogenous rhythm with a circatidal component, or is simply a result of feeding and associated physiological changes needs to be tested. Together, these data suggest that the baseline B rhythm in marine iguanas is influenced by the tidal cycle/food intake as well as the light:dark cycle.
Surgical Dilemmas: Diagnosis and Treatment of Atrial Plasmacytoma

Treating heart masses demands a well-planned diagnostic strategy. As with any disease in medicine, the confirmation of a diagnosis leads to a tailored, more efficacious treatment. We present the case of a 72-year-old man presenting with a right atrial mass on echocardiography and diagnosis of plasmacytoma after transvenous endomyocardial biopsy.
Dopamine receptors in human lymphocytes : Radioligand binding and quantitative RT-PCR assays

Analysis of dopamine receptors (DR) in lymphocytes of the human peripheral blood mononuclear cell (PBMC) fraction is an attractive tool for evaluation of functional properties of dopaminergic function underlying variation in complex psychological/psychopathological traits. Receptor binding assays (RBAs) with selective radioligands, which are widely used in CNS studies, have not produced consistent results when applied to isolated PBMC. We tested the assay conditions that could be essential for detection of DR in human PBMC and their membrane preparations. Using [(3)H]SCH23390, a dopamine D1-like receptor antagonist, we demonstrated the presence of two binding sites in PBMC-derived membrane fraction. One of them is characterized by the K(d) value consistent with that reported for D5 dopamine receptors in human lymphocytes, whereas the other K(d) value possibly corresponds to serotonin receptor(s). Although D5 receptor binding sites in PBMC membranes could be characterized by binding assays, the low protein expression and the large volume of blood needed for membrane preparation render the binding method impracticable for individual phenotyping. In contrast, real-time RT-PCR may be used for this purpose, contingent on the relationship between DR expression in the brain and in lymphocytes. The expression of the DRD2-DRD5 genes, as detected by this method, varied widely among samples, whereas the DRD1 expression was not detected. The expression levels were comparable with those in the brain for DRD3 and DRD4, and were significantly lower for DRD2 and DRD5.
Standards for Assessment of Lung Function and Respiratory Health in Minority Populations: Some Challenges Linger Into the New Millennium

Results of pulmonary function tests (as an indicator of respi- ratory health) are from 11 to 13 percent lower in African Americans and other racial ethnic populations than in Caucasians when controlled for gender, age, and height. Environmental factors influencing these indices are arcadian variation, altitude, air pollutants, technology, state of nutri- tion, smoking history, and other indicators of lifestyle. A. combination of subtle, genetically determined anthropometric variants may also be oper- ative, the extent of which is controversial. Population-based, population- specific standards are required to avoid erroneous diagnosis of cardio- respiratory disease, erroneous assessment of operative risk, unfair hiring practices when lungfunction tests are used for preemployment evaluation in dusty occupations, and unfair labeling when workers apply for disabil- ity compensation. Tailoring of statistical prediction standards from sim- ple linear to more complex polynomial regression models will increase the accuracy ofpopulation prediction standards for pulmonary function vari- ables into the 21st century.
fMRI of Monkey Visual Cortex

While functional magnetic resonance imaging (fMRI) is now used widely for demonstrating neural activity-related signals associated with perceptual, motor, and cognitive processes in humans, to date this technique has not been developed for use with nonhuman primates. fMRI in monkeys offers a potentially valuable experimental approach for investigating brain function, which will complement and aid existing techniques such as electrophysiology and the behavioral analysis of the effects of brain lesions. There are, however, a number of significant technical challenges involved in using fMRI with monkeys. Here, we describe the procedures by which we have overcome these challenges to carry out successful fMRI experiments in an alert monkey, and we present the first evidence of activity-related fMRI signals from monkey cerebral cortex.