cssi/SciSciGPT-SciSciNet huggingface dataset:
A Dynamics Simulator for Soft Growing Robots

Simulating soft robots in cluttered environments remains an open problem due to the challenge of capturing complex dynamics and interactions with the environment. Furthermore, fast simulation is desired for quickly exploring robot behaviors in the context of motion planning. In this paper, we examine a particular class of inflated-beam soft growing robots called "vine robots," and present a dynamics simulator that captures general behaviors, handles robot-object interactions, and runs faster than real time. The simulator framework uses a simplified multi-link, rigid-body model with contact constraints. To bridge the sim-to-real gap, we develop methods for fitting model parameters based on video data of a robot in motion and in contact with an environment. We provide examples of simulations, including several with fit parameters, to show the qualitative and quantitative agreement between simulated and real behaviors. Our work demonstrates the capabilities of this high-speed dynamics simulator and its potential for use in the control of soft robots.
Vps54 Regulates Lifespan and Locomotor Behavior in Adult Drosophila melanogaster .

Vps54 is an integral subunit of the Golgi-associated retrograde protein (GARP) complex, which is involved in tethering endosome-derived vesicles to the trans-Golgi network (TGN). A destabilizing missense mutation in Vps54 causes the age-progressive motor neuron (MN) degeneration, muscle weakness, and muscle atrophy observed in the wobbler mouse, an established animal model for human MN disease. It is currently unclear how the disruption of Vps54, and thereby the GARP complex, leads to MN and muscle phenotypes. To develop a new tool to address this question, we have created an analogous model in Drosophila by generating novel loss-of-function alleles of the fly Vps54 ortholog (scattered/scat). We find that null scat mutant adults are viable but have a significantly shortened lifespan. Like phenotypes observed in the wobbler mouse, we show that scat mutant adults are male sterile and have significantly reduced body size and muscle area. Moreover, we demonstrate that scat mutant adults have significant age-progressive defects in locomotor function. Interestingly, we see sexually dimorphic effects, with scat mutant adult females exhibiting significantly stronger phenotypes. Finally, we show that scat interacts genetically with rab11 in MNs to control age-progressive muscle atrophy in adults. Together, these data suggest that scat mutant flies share mutant phenotypes with the wobbler mouse and may serve as a new genetic model system to study the cellular and molecular mechanisms underlying MN disease.
Hypoellipticity and the Mori–Zwanzig formulation of stochastic differential equations

We develop a thorough mathematical analysis of the effective Mori–Zwanzig (EMZ) equation governing the dynamics of noise-averaged observables in stochastic differential equations driven by multiplicative Gaussian white noise. Building upon recent work on hypoelliptic operators, we prove that the EMZ memory kernel and fluctuation terms converge exponentially fast in time to a unique equilibrium state that admits an explicit representation. We apply the new theoretical results to the Langevin dynamics of a high-dimensional particle system with smooth interaction potential.
Background-Suppressed High-Throughput Mid-Infrared Photothermal Microscopy via Pupil Engineering

Mid-infrared photothermal (MIP) microscopy has been a promising label-free chemical imaging technique for functional characterization of specimens owing to its enhanced spatial resolution and high specificity. Recently developed wide-field MIP imaging modalities have drastically improved speed and enabled high-throughput imaging of micron-scale subjects. However, the weakly scattered signal from sub-wavelength particles becomes indistinguishable from the shot-noise as a consequence of the strong background light, leading to limited sensitivity. Here, we demonstrate background-suppressed chemical fingerprinting at a single nanoparticle level by selectively attenuating the reflected light through pupil engineering in the collection path. Our technique provides over three orders of magnitude background suppression by quasi-darkfield illumination in epi-configuration without sacrificing lateral resolution. We demonstrate 6-fold signal-to-background noise ratio improvement, allowing for simultaneous detection and discrimination of hundreds of nanoparticles across a field of view of 70 um x 70 um. A comprehensive theoretical framework for photothermal image formation is provided and experimentally validated with 300 and 500~nm PMMA beads. The versatility and utility of our technique are demonstrated via hyperspectral dark-field MIP imaging of S. aureus and E. coli bacteria.
A global cancer data integrator reveals principles of synthetic lethality, sex disparity and immunotherapy.

Background Advances in cancer biology are increasingly dependent on integration of heterogeneous datasets. Large-scale efforts have systematically mapped many aspects of cancer cell biology; however, it remains challenging for individual scientists to effectively integrate and understand this data. Results We have developed a new data retrieval and indexing framework that allows us to integrate publicly available data from different sources and to combine publicly available data with new or bespoke datasets. Our approach, which we have named the cancer data integrator (CanDI), is straightforward to implement, is well documented, and is continuously updated which should enable individual users to take full advantage of efforts to map cancer cell biology. We show that CanDI empowered testable hypotheses of new synthetic lethal gene pairs, genes associated with sex disparity, and immunotherapy targets in cancer. Conclusions CanDI provides a flexible approach for large-scale data integration in cancer research enabling rapid generation of hypotheses. The CanDI data integrator is available at https://github.com/GilbertLabUCSF/CanDI .
Project 412Connect: Bridging Students and Communities

In this work, we describe some of the challenges Black-owned businesses face in the United States and specifically in the city of Pittsburgh. Taking into account local dynamics and the communicated desires of Black-owned businesses in the Pittsburgh region, we determine that university students represent an under-utilized market for these businesses. We investigate the root causes for this inefficiency and design and implement a platform, 412Connect (https://www.412connect.org/), to increase online support for Pittsburgh Black-owned businesses from students in the Pittsburgh university community. The site operates by coordinating interactions between student users and participating businesses via targeted recommendations. We describe the project from its conception, paying special attention to our motivation and design choices. These choices are aided by two simple models for badge design and recommendation systems that may be of theoretical interest. Along the way, we highlight challenges and lessons from coordinating a grassroots volunteer project working in conjunction with community partners and the opportunities and pitfalls of engaged scholarship.
Computer-assisted proofs of congruences for multipartitions and divisor function convolutions, based on methods of differential algebra

This paper provides elementary proofs for several types of congruences involving multipartitions and self-convolutions of the divisor function. Our computations use differential algebra and Grobner bases, and employ a couple of MAPLE programs available as ancillary files on arXiv. The first results of the paper are Ramanujan-type congruences of the form $$p^{*k}(qn+r) \equiv _q 0$$ and $$\sigma ^{*k}(qn+r) \equiv _q 0$$ , where p(n) and $$\sigma (n)$$ are the partition and divisor functions, $$q > 3$$ is prime, $$\equiv _q$$ denotes congruence modulo q, and $$^{*k}$$ denotes kth-order self-convolution. We prove all the valid congruences of this form for $$q \in \{5, 7, 11\}$$ , including the three famous partition congruences of Ramanujan, and an exceptional one for $$q = 17$$ . All such multipartition congruences have already been settled in principle (up to a numerical verification) due to Eichhorn and Ono, using modular forms. On the other hand, the majority of the divisor function congruences are new results. We then proceed to search for more general congruences modulo small primes, concerning linear combinations of $$\sigma ^{*k}(qn+r)$$ for different values of k, as well as weighted convolutions of p(n) and $$\sigma (n)$$ with polynomial weights. The paper ends with a few corollaries and extensions for the divisor function congruences, including proofs for three conjectures of N.C. Bonciocat.
Tuning the Room Temperature Ferromagnetism in Fe5GeTe2 by Arsenic Substitution

In order to tune the magnetic properties of the cleavable high-Curie temperature ferromagnet Fe$_{5-x}$GeTe$_2$, the effect of increasing the electron count through arsenic substitution has been investigated. Small additions of arsenic (2.5 and 5%) seemingly enhance ferromagnetic order in polycrystalline samples by quenching fluctuations on one of the three magnetic sublattices, whereas larger As concentrations decrease the ferromagnetic Curie temperature ($T_{\rm C}$) and saturation magnetization. This work also describes the growth and characterization of Fe$_{4.8}$AsTe$_2$ single crystals that are structurally analogous to Fe$_{5-x}$GeTe$_2$ but with some phase stability complications. Magnetization measurements reveal dominant antiferromagnetic behavior in Fe$_{4.8}$AsTe$_2$ with a N\'{e}el temperature of $T_{\rm N}$ $\approx$42K. A field-induced spin-flop below $T_{\rm N}$ results in a switch from negative to positive magnetoresistance, with significant hysteresis causing butterfly-shaped resistance loops. In addition to reporting the properties of Fe$_{4.8}$AsTe$_2$, this work shows the importance of manipulating the individual magnetic sublattices in Fe$_{5-x}$GeTe$_2$ and motivates further efforts to control the magnetic properties in related materials by fine tuning of the Fermi energy or crystal chemistry.
Promoting resilience in healthcare workers during the COVID-19 pandemic with a brief online intervention

Abstract Introduction The psychological wellbeing of healthcare workers has been impacted by the high levels of stress many have experienced during the Coronavirus Disease 2019 (COVID-19) pandemic. This study aimed to examine the feasibility and acceptability of a brief online course focused on introducing evidence-based skills that could increase resilience and decreases emotional distress in healthcare workers during the pandemic. Materials and methods Employees of a large healthcare system completed a mental health survey at baseline, and then one month and two months after some employees participated in an online resilience-enhancement course consisting of three 12–19 min videos focused on mindfulness, mentalization, and self-compassion. Results A total of 554 participants completed the baseline survey, endorsing moderate to high levels of emotional distress. Of those who completed all three assessments and participated in the course (n = 38), significant improvements in resilience and reductions in emotional distress were found across two months, in comparison to those who did not participate in the course (n = 110). Discussion: These findings suggest that a brief, online intervention can improve the mental health of healthcare workers during a crisis such as the COVID-19 pandemic.
Connections between finite difference and finite element approximations

We present useful connections between the finite difference and the finite element methods for a model boundary value problem. We start from the observation that, in the finite element context, the interpolant of the solution in one dimension coincides with the finite element approximation of the solution. This result can be viewed as an extension of the Green function formula for the solution at the continuous level. We write the finite difference and the finite element systems such that the two corresponding linear systems have the same stiffness matrices and compare the right hand side load vectors for the two methods. Using evaluation of the Green function, a formula for the inverse of the stiffness matrix is extended to the case of non-uniformly distributed mesh points. We provide an error analysis based on the connection between the two methods, and estimate the energy norm of the difference of the two solutions. Interesting extensions to the 2D case are provided.
Entropy spectrum of rotation classes

Abstract In this note we study the entropy spectrum of rotation classes for collections of finitely many continuous potentials φ 1 , … , φ m : X → R with respect to the set of invariant measures of an underlying dynamical system f : X → X . We show for large classes of dynamical systems and potentials that these entropy spectra are maximal in the sense that every value between zero and the maximum is attained. We also provide criteria that imply the maximality of the ergodic entropy spectra. For m being large, our results can be interpreted as a complimentary result to the classical Riesz representation theorem in the dynamical context.
Composite entanglement topology and extensional rheology of symmetric ring-linear polymer blends

Extensive molecular simulations are applied to characterize the equilibrium dynamics, entanglement topology, and nonlinear extensional rheology of symmetric ring-linear polymer blends with systematically varied ring fraction ϕR. Chains with degree of entanglement Z≈14 are mixed to produce 10 well-entangled systems with ϕR varying from neat linear to neat ring melts. Z is large enough that except for very large ϕR, the rings are threaded by multiple linear chains in equilibrium. Primitive path analysis is used to visualize and quantify the structure of the composite ring-linear entanglement network. We measure the quantity of ring-linear threading and linear-linear entanglement as a function of ϕR and identify with simple arguments a ring fraction ϕR≈0.4 where the topological constraints of the composite entanglement network are maximized. These topological analyses are used to rationalize the ϕR-dependence of ring and linear chain dynamics, conformations, and rheology. Simulations of startup uniaxial elongation flows demonstrate the extensional stress overshoot observed in recent filament stretching experiments and characterize how it depends on the blend composition and entanglement topology. The overshoot is driven by an overstretching and recoil of ring polymers due to the convective unthreading of rings from linear chains.
Training data composition affects performance of protein structure analysis algorithms

The three-dimensional structures of proteins are crucial for understanding their molecular mechanisms and interactions. Machine learning algorithms that are able to learn accurate representations of protein structures are therefore poised to play a key role in protein engineering and drug development. The accuracy of such models in deployment is directly influenced by training data quality. The use of different experimental methods for protein structure determination may introduce bias into the training data. In this work, we evaluate the magnitude of this effect across three distinct tasks: estimation of model accuracy, protein sequence design, and catalytic residue prediction. Most protein structures are derived from X-ray crystallography, nuclear magnetic resonance (NMR), or cryo-electron microscopy (cryo-EM); we trained each model on datasets consisting of either all three structure types or of only X-ray data. We find that across these tasks, models consistently perform worse on test sets derived from NMR and cryo-EM than they do on test sets of structures derived from X-ray crystallography, but that the difference can be mitigated when NMR and cryo-EM structures are included in the training set. Importantly, we show that including all three types of structures in the training set does not degrade test performance on X-ray structures, and in some cases even increases it. Finally, we examine the relationship between model performance and the biophysical properties of each method, and recommend that the biochemistry of the task of interest should be considered when composing training sets.
A coarse-grained NADH redox model enables inference of subcellular metabolic fluxes from fluorescence lifetime imaging.

Mitochondrial metabolism is of central importance to diverse aspects of cell and developmental biology. Defects in mitochondria are associated with many diseases, including cancer, neuropathology, and infertility. Our understanding of mitochondrial metabolism in situ and dysfunction in diseases are limited by the lack of techniques to measure mitochondrial metabolic fluxes with sufficient spatiotemporal resolution. Herein, we developed a new method to infer mitochondrial metabolic fluxes in living cells with subcellular resolution from fluorescence lifetime imaging of NADH. This result is based on the use of a generic coarse-grained NADH redox model. We tested the model in mouse oocytes and human tissue culture cells subject to a wide variety of perturbations by comparing predicted fluxes through the electron transport chain (ETC) to direct measurements of oxygen consumption rate. Interpreting the FLIM measurements of NADH using this model, we discovered a homeostasis of ETC flux in mouse oocytes: perturbations of nutrient supply and energy demand of the cell do not change ETC flux despite significantly impacting NADH metabolic state. Furthermore, we observed a subcellular spatial gradient of ETC flux in mouse oocytes and found that this gradient is primarily a result of a spatially heterogeneous mitochondrial proton leak. We concluded from these observations that ETC flux in mouse oocytes is not controlled by energy demand or supply, but by the intrinsic rates of mitochondrial respiration.
Generating Metaphors from Networks: A Formal Interpretation of the Semantic Field Theory of Metaphor

Metaphor’s peculiar property to yield cognitive insight — often in otherwise false sentences — has been the focus of contemporary studies of metaphor. In Metaphor: Its Linguistic Structure and Cognitive Force, Kittay (1987) attempts to understand the cognitive force of metaphor by utilizing semantic field theory — a theory that assimilates conceptual structure to a semantic structure underlying the utterances we produce. According to semantic field theory, the meaning of a word is, in part, a function of its relation to words occupying the same conceptual terrain. For example, “red” takes its meaning, in part, from the other color terms in the language, terms with which it has the semantic relation of co-hyponym. Similarly, the meaning of “hot,” is determined, in part, in contrast to other terms in a gradable antonymy, that is, in contrast to “cold,” “warm,” and “cool.” The meaning of terms is also a function, in part, of the words with which they can collocate. For example, “fisherman” stands in the relation of AGENT to the verb “fish.” That is, at least part of what it means to be a fisherman is to be one who engages in the action of fishing. Furthermore, semantic field theory proposes that the lexicon is organized along conceptual affinities and contrasts reflected in the semantic relations that structure fields.
The Transtemporal Subperiosteal Approach for Midface Lifting

With an increased understanding of facial aging changes and midface anatomy, midface surgical techniques have achieved greater popularity in the management of lower eyelid and facial reconstruction and rejuvenation. In lower eyelid reconstruction and retraction management, midface skin recruitment through vertical lifting techniques may decrease the necessity for full-thickness skin grafting. Since the landmark descriptions by Shorr, the transeyelid subperiosteal midface lift combined with a lower eyelid spacer graft is an effective means to manage surgically lower eyelid retraction [1–5]. A serendipitous side effect of this vertical recruitment was midfacial rejuvenation via the elevation of the malar fat pad.
Distribution of microbial assemblages in the Central Arctic Ocean Basin studied by PCR/DGGE: analysis of a large data set

Analysis of the biogeographic distributions of bacteria has been limited by potential biases inherent in the isolations required for classical taxonomy and by the time required for phylogenetic analyses. We have attempted to circumvent both of these limitations by using denaturing gradient gel electrophoresis (DGGE) to resolve the products of polymerase chain reaction (PCR) amplifications of mixed template DNA isolated from microbial communities. DGGE separates DNA fragments based on their denaturation characteristics, which vary with the nucleotide sequence of the fragment. The banding patterns in the electropherograms were then subjected to similarity analysis using pattern matching and band comparison software. Replication experiments tested the robustness of band patterns within and between gels. Samples were collected from the Central Arctic Ocean basin during April of 1995 on the SCICEX 95 cruise of the USS Cavalla. One hundred samples collected from a depth of 59 m are the focus of this biogeographical analysis. The band identification algorithm of the software identified between 12 and 30 bands (operational taxonomic units, OTUs) per sample (mean: 21.5) with minimal editing. This number approximately doubled with more extensive editing. Four OTUs seemed to be common to most samples. The samples grouped into five major clusters with similarities greater than approximately 80%. Twenty nine samples in one of these clusters were in two branches with internal similarities greater than approximately 90%. These samples had relatively nondescript banding patterns (numerous bands with roughly equal intensity). Another cluster contained 15 samples with distinctive banding patterns dominated by one or two intense bands. These samples were collected in the same general area of the Arctic Ocean (Canada Basin) and may reflect a community response to local environmental conditions.
Therapeutic approaches to enhance natural killer cell cytotoxicity against cancer: the force awakens

Although natural killer (NK) cells can induce immune responses against malignancies, their therapeutic potential in the clinic is largely unexplored. In this Review, Childs and Carlsten discuss recent insights into NK cell biology and how these can be used for the development of new immunotherapeutic strategies against cancer.
Newton relaxation algorithms for simulating large power systems

Three methods based on Newton relaxation for simulating large power systems are developed. Large systems are partitioned into smaller subsystems using partition points called cut-nodes. The Newton relaxation algorithm is used to update the variables on the cut-nodes depending on the difference of power flow or the voltages of adjacent cutnodes. Hence, there are two nested iteration loops. Three methods are developed. Method I, the Newton voltage relaxation, utilizes power residuals and adjusts voltages between each pair of adjacent cut-nodes on two adjacent blocks, Method II, the Newton power relaxation, employ, voltage residuals, and cut-node power is adjusted. Method III, called fast decoupled relaxation, uses the imaginary part of the bus admittance (bus susceptance) matrix in place of Jacobian matrices. >
Primary vitrectomy for pseudophakic and aphakic retinal detachments.

Purpose To evaluate primary vitrectomy for the treatment of pseudophakic and aphakic retinal detachments. Primary vitrectomy may enable better identification of retinal breaks than scleral buckling procedures. Methods A prospective study was performed of primary vitrectomy for the treatment of 25 consecutive cases of pseudophakic and aphakic retinal detachment. Results The primary retinal reattachment rate was 84% (21 eyes). Surgical failure resulted from new/missed retinal breaks (2 eyes) and proliferative vitreoretinopathy (2 eyes). The final retinal reattachment rate with further surgery was 96% (24 eyes). There were 7 macula-on detachments which all retained their presenting visual acuity. A visual acuity of 6/18 or better was achieved by 56% of the 18 macula-off detachments. Visualisation of the peripheral retina was impaired in 17 eyes and procedures to improve visualisation were performed in 7 eyes. Retinal breaks were detected in 16 eyes at surgery that had not been identified pre-operatively. Raised intraocular pressure was the most common complication, affecting 10 eyes in the early post-operative period. Conclusions Primary vitrectomy offers certain advantages in the treatment of pseudophakic and aphakic retinal detachments. A controlled study is required to determine whether primary vitrectomy achieves a better outcome than scleral buckling procedures for these retinal detachments.
Central noradrenergic mechanisms and the acute stress response during painful stimulation

Events that threaten tissue integrity including noxious stimulation activate central noradrenergic circuits, particularly locus coeruleus and its projections. Recent advances in theory hold that an adaptive, defensive shift in brain activity takes place in response to threat. In principle, this shift may accentuate the autonomic and central biomarkers of the perception of painful events and the experience of pain itself. We have examined the effects of an alpha-2 agonist on pupil dilation responses, skin conductance responses, near field somatosensory evoked potentials and pain reports in normal volunteers undergoing repeated trials of painful fingertip stimulation delivered at low, medium and high intensities. In a double-blinded study, 114 healthy male and female volunteers underwent repeated noxious stimulation under baseline, placebo and active drug conditions where the active drug was the alpha-2 agonist tizanidine 4 mg. In contrast to baseline and placebo conditions, tizanidine 4 mg significantly reduced the magnitudes of the mean pupil dilation response, the mean skin conductance response, the mean near field somatosensory evoked potential peak-to-peak amplitude and the mean pain intensity rating. Stimulus intensity significantly altered all three biomarkers and the pain report in a graded fashion. There were no sex differences. These findings support the hypotheses that painful events activate central noradrenergic circuits, and that these circuits play a role in the autonomic and central arousal associated with pain.
The Impact of Standardization and Systematic Problem Solving on Team Member Learning and Its Implications for Developing Sustainable Continuous Improvement Capabilities

It is important for organizations to understand the factors responsible for establishing sustainable continuous improvement (CI) capabilities. This study uses learning curve experiments to examine learning obtained by team members (TMs) doing work with and without the application of fundamental aspects of the Toyota Production System (TPS). The results are used to develop a model to guide organizational activities toward achieving the ability to continuously improve in a sustainable fashion. This study uses learning curve experiments in model production cells to examine TM learning with and without the application of key elements of TPS to more clearly understand the role of systematic problem solving and standardization in creating sustainable CI processes. The results indicate that application of standardized work principles and elimination of formally defined waste using a systematic problem-solving methodology positively impacts TM learning and performance, providing the foundation for CI. Compared to...
Progesterone, 5α-dihydroprogesterone and R5020 binding in female rat anterior pituitary☆

Abstract Progestin binding, which may represent receptor binding, was examined in female rat anterior pituitary cytosol. Specific progesterone, 5α-dihydroprogesterone (5α-DHP) and R5020 binding, as well as cortico-steroid binding globulin (CBG)-like complexes, were assayed in cytosol from five animal models: estradiol benzoate primed-ovariectomized-adrenalectomized (EB-OVX-ADX), ovariectomized-adrenalecto-mized (OVX-ADX), estradiol benzoate primed-ovariectomized (EB-OVX), ovariectomized (OVX) and intact rats. With all three progestins, estrogen priming consistently and significantly enhanced specific binding levels, and cytosol from EB-OVX-ADX rats had the greatest amount of binding. In contrast, presumptive CBG-like levels increased with adrenalectomy but not with EB treatment. Specific progesterone and 5α-DHP complexes dissociated more rapidly during Sephadex LH-20 elution than specific R5020 and CBG-like binding complexes. Maximal values for progesterone and 5α-DHP binding were rapidly attained at 4°C and the binding was decreased in the presence of protease, but not DNase or RNase. 5α-DHP binding had an apparent K d of 0.9 to 2 × 10 −9 M and the number of binding sites increased with EB treatment in the OVX-ADX rat. The 5α-DHP binding exhibited greater specificity for progestins (particularly progesterone and R5020) than for androgens, glucocorticoids or estradiol.
THE ARTIFICIAL INTELLIGENCE OF URBAN DYNAMICS: NEURAL NETWORK MODELING OF URBAN STRUCTURE

A neural network, parallel distributed processing model of learning is adapted to represent the self-organizing urban system. The model is trained on a number of cases representing specific functional states of the system, and as a result “learns,” by a process of structural evolution, to recognize the general problem defined implicitly by the set of cases, and to solve it. The learning algorithm approach is based on an explicit distinction between the functional and structural organization of the system; questions such as the structural effects of a functional change are thus addressed directly. Specific results show that very simple models can “learn” to create transportation infrastructure appropriate for a variety of flow requirements, and then distribute flows in a reasonable manner over the network.
Determination of d-limonene in adipose tissue by gas chromatography-mass spectrometry.

Abstract We developed a novel method for analyzing d-limonene levels in adipose tissue. Fat samples were subjected to saponification followed by solvent extraction. d-Limonene in the sample extract was analyzed using gas chromatography–mass spectrometry (GC–MS) with selected ion monitoring. Linear calibration curves were established over the mass range of 79.0–2529 ng d-limonene per 0.1 g of adipose tissue. Satisfactory within-day precision (R.S.D. 6.7–9.6%) and accuracy (%difference of −2.7 to 3.8%) and between-day precision (R.S.D. 6.0–10.7%) and accuracy (%difference of 1.8–2.6%) were achieved. The assay was successfully applied to human fat biopsy samples from a d-limonene feeding trial.
Picosecond Streak Camera Diagnostics Of C0 2 Laser-Produced Plasmas

The interaction of intense laser radiation with solid targets is currently of considerable interest in laser fusion studies. Its understanding requires temporal knowledge of both laser and plasma parameters on a pico-second time scale. In this paper we describe the progress we have recently made in analysing, with picosecond time resolution, various features of intense nanosecond CO2 laser pulse interaction experiments. An infrared upconversion scheme, having linear response and <20 ps temporal resolution, has been utilized to characterise the 10 μm laser pulse. Various features of the interaction have been studied with the aid of pico-second IR and x-ray streak cameras. These include the temporal and spatial characteristics of high harmonic emission from the plasma, and the temporal development of the x-ray continuum spectrum.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Fine Temporal Structure of Beta Oscillations Synchronization in Subthalamic Nucleus in Parkinson's Disease

Synchronous oscillatory dynamics in the beta frequency band is a characteristic feature of neuronal activity of basal ganglia in Parkinson's disease and is hypothesized to be related to the disease's hypokinetic symptoms. This study explores the temporal structure of this synchronization during episodes of oscillatory beta-band activity. Phase synchronization (phase locking) between extracellular units and local field potentials (LFPs) from the subthalamic nucleus (STN) of parkinsonian patients is analyzed here at a high temporal resolution. We use methods of nonlinear dynamics theory to construct first-return maps for the phases of oscillations and quantify their dynamics. Synchronous episodes are interrupted by less synchronous episodes in an irregular yet structured manner. We estimate probabilities for different kinds of these “desynchronization events.” There is a dominance of relatively frequent yet very brief desynchronization events with the most likely desynchronization lasting for about one cycle of oscillations. The chances of longer desynchronization events decrease with their duration. The observed synchronization may primarily reflect the relationship between synaptic input to STN and somatic/axonal output from STN at rest. The intermittent, transient character of synchrony even on very short time scales may reflect the possibility for the basal ganglia to carry out some informational function even in the parkinsonian state. The dominance of short desynchronization events suggests that even though the synchronization in parkinsonian basal ganglia is fragile enough to be frequently destabilized, it has the ability to reestablish itself very quickly.
Application of robust control techniques to a mobile robot system

This article deals with the stabilization problem of a class of nonlinear second-order multivariable dynamical systems with bounded uncertainties. A robust discontinuous controller is proposed to guarantee asymptotic stability of this class of systems. Then, to guarantee the continuity of the control, a quasi-saturation function is introduced into the control law. Guaranteed eventual stability-in-the-large (ESL) of the dynamical systems is proved with the continuous, robust controller, which is much different from the standard “computed-torque control.” The controller requires known bounding functions that are easier to determine as well as more general than the bounds needed in other approaches. An application is given to trajectory-following control for a two-link mobile robot. © 1992 John Wiley & Sons Inc.
Deducing solid–liquid interfacial energy from superheating or supercooling: application to H2O at high pressures

We present a general method to determine the solid?liquid interfacial energy (?sl) from the maximum supercooling (or superheating), and apply it to the water?ice system. For solid?liquid phase transitions, the nucleation-theory-based systematics of maximum superheating and supercooling relate a dimensionless nucleation barrier to the superheating (supercooling) and heating (cooling) rates. Given superheating (or supercooling) values from either experiments or simulations, ?sl can then be deduced from the dimensionless nucleation barrier, equilibrium melting temperature and enthalpy of fusion. We demonstrate the accuracy of this approach using molecular dynamics (MD) simulations of the Lennard?Jones system: our predictions of ?sl at various pressures are in excellent agreement with independent, direct MD simulations. With this approach, we predict ?sl for the water?ice (Ih and III) system using experimental supercooling values in the pressure range of 0?0.3?GPa. The predicted value (28 ? 0.8?mJ?m?2) agrees with measurements on H2O?Ih at ambient pressure.
BiSb alloys for magneto-thermoelectric and thermomagnetic cooling

Abstract The thermoelectric and thermomagnetic properties of undoped Bi-Sb alloys have been investigated with highly homogeneous single crystals throughout the entire alloy composition as functions of temperature (77–300°K), magnetic field (0–7·5 kilo-oersteds), and crystallographic direction (∥ and ⊥ to the trigonal axis). The undoped, n-type Bi85Sb15 alloy gave the largest magneto-thermoelectric figure of merit (11 × 10−3 deg−1) at 100°K and the same value at 80°K in transverse fields of 3 and 1·3 kilo-oersteds, respectively. Within the range of field intensity used, the largest thermomagnetic figure of merit (4·1 × 10−3 deg−1) was obtained at 100°K with undoped n-types Bi99Sb1 in a field of 7·5 kilo-oersteds. The possibility has been explored of obtaining p-type Bi-Sb alloys through additions of acceptor impurities and by applying transverse magnetic fields. The results showed that a Sn-doped Bi88Sb12 alloy yields a p-type figure of merit of 2·3 × 10−3 deg−1 at 85°K in 7·5 kilo-oersteds. The difference between the adiabatic and isothermal conditions was reviewed in some detail in connection with measurements of various transport coefficients that enter into the calculation of the figures of merit. Also, a comparison was given on the difference between the magneto-Peltier and the Ettingshausen cooling. With a hybrid cooling unit based on the combination of the Peltier and magneto-Peltier effects in telluride alloys and BiSb alloys, respectively, a continuous cooling as large as 172°K, from room temperature down to 128°K, has been achieved.
A possible model for a singularity without collisions in the five body problem

Abstract A heuristic solution is described for the five body problem in the plane in which all five bodies escape to infinity in a finite time.
Comparison of divergence-free algorithms for 3D MRI with three-directional velocity encoding

Summary Two divergence-free algorithms (finite difference and radial basis functions) are evaluated for improving the flow visualization quality of PC-VIPR 4D flow data. Both methods improve streamline length, with the finite difference method performing slightly better. Background The velocity-to-noise ratio in 4D MR Flow acquisitions can suffer, particularly for low velocity segments, because the velocity encoding settings are adjusted to the highest velocities in the volume. Blood is essentially incompressible so vascular velocity fields should be divergence free. Therefore, any remaining divergence in an acquired 3D or 4D MR flow dataset can be assumed to originate from image noise, which can be reduced by imposing divergence free conditions. Several methods have been proposed to reconstruct a divergence free velocity vector field, yet to our knowledge no comparison studies exist to explore their properties in flow MRI data. This study compares two methods in their effectiveness at improving flow visualizations, the finite difference method (FDM)[1] and the radial basis function (RBF)[2] based approach, which differ in their handling of noise and boundary conditions. Methods MR flow data were acquired in a straight tube flow phantom and the internal carotid arteries of a volunteer on a clinical 3T scanner with a 3D radially undersampled acquistion (PC-VIPR)[3]. Time resolved PCVIPR images were acquired as follows: scan time: 6 min acquired isotropic spatial resolution: 0.68 mm, TR/TE = 8.3/2.9 ms, temporal resolution: 39.5 ms. The FDM algorithm is solved with a fast Fourier solver for the Poisson equation. The RBF algorithm includes a normalized convolution, and is solved using iterative least squares. The quality of the resulting flow fields was quantified by average streamline lengths and streamline counts that extended from the emitter plane to a distal portion in the flow phantom or vessel. Data fidelity was measured by comparing flow values pre and post processing in the emitter and analysis planes. Results
Breast Cancer Risk Assessment and Counseling: A Clinician's Guide

Abstract: Most individuals concerned about hereditary breast cancer risk will neither order nor benefit from genetic testing at the present time. Many will, however, seek information about their risk and testing. Risk assessment services, in addition to providing information about hereditary risk and genetic testing, need also to include assessment of non-hereditary risks, information about how to evaluate risks, early detection modalities, the etiology of cancer, and assistance in devising follow-up health care plans. Psychosocial factors, particularly those pertaining to the individual's past history with illness and beliefs about causes and prognosis, must be taken into account to provide relevant information that is understood. A case history with examples of some of the types of information that lead to informed consent in a cancer risk assessment setting is provided.
POINT: A Prescription to Decrease Left Ventricular Function

The Courage Trial, published in 2007, has significantly reduced the incidence of treating stable angina with angioplasty. The investigators randomized 2297 patients with documented cardiac ischemia to conservative or invasive therapy and concluded that there was no difference in major events during a follow-up of 2.5 to 7 years and that the urge to open the narrowed artery was unjustified. Over the years it has been well documented by myocardial biopsy that repeated ischemic episodes result in replacement of myocardial cells by fibrous tissue, loss of mitochondria, and deterioration of left ventricular function. Ischemic episodes often occur in the absence of angina so that it is impossible to determine whether the therapy is reducing the magnitude or duration of the process. Also, in their study, 32% of the conservatively treated patients crossed over to invasive. The evidence indicated that conservative treatment may result in a progressive decrease in left ventricular function.
Critical Research and the Future of Literacy Education.

-ZTa_11 A -ZTa_11 over the globe those who "have" are outperforming the "have-nots" in literacy education, with serious implications. Generally, the differences in achievement are easily predictable along the lines of race, class, gender, and language background (College Board, 2005; Perie, Grigg, & Donahue, 2005). Certainly there are structural and cultural contexts, including inequitable access to resources and institutionalized racism, that problematize the concept of the achievement gap, but these differences in academic performance still carry significant social, economic, and political consequences. At a time when we need to expand our literacy research horizons to address issues of equity and excellence in literacy education, research practices are often narrowly focused on large standardized measures that make it difficult to tease out the nuances of exemplary classroom practice. In the United States, for instance, many state departments of education rank schools only according to aggregate test scores. These standardized tests are generally taken in the spring and the results are made available the following school year. Schools that perform poorly are often threatened with takeover or the loss of resources, and administrators are challenged to offer more basic and traditional curricula delivered through a teacher-centered pedagogy to increase their scores by a number of percentage points. Taken as a whole, these tests do not tell us a great deal about what is happening or what is possible in language and literacy education. They do not help us understand how teacher experience, institutionalized racism, culturally alienating curricula, or test anxiety affect the scores of schools serving populations that are largely nonwhite or low income. What's more, the tests do not tell us about the tremendous opportunity gaps that exist between the wealthiest and the poorest students (Hilliard, 2003). They do not tell us about what is working in settings where individual students or classrooms are excelling; furthermore, these tests tell us nothing about how teachers informally assess students throughout the academic year, how they make connections between students' lived experiences and the world of academic literacy, or how students become motivated to see themselves as intellectuals and empowered 96
Tribal identity and alliance behaviour among factions of the Kurdish national movement in Iraq

While most of the current literature on secessionist and nationalist movements treats them as a collective whole, the author of this paper argues that these movements do not always act as a cohesive unit in their attempts to achieve their nationalist aspirations. The article demonstrates that primary loyalty to sectarian group identity within these movements impacts on their alliance behaviour with the central government and foreign powers. The article integrates international relations theory and nationalism and group behaviour theories and applies them to factions of the Kurdish national movement in Iraq.
Management Mentoring in a Social Service Organization

Abstract Interviews exploring the experiences of administrators in a state social service organization found informal mentoring relationships to be common and individually beneficial. Ninety-two percent (92%) of the managers reported having had a mentor and 77% reported that they had served as a mentor. All reported receiving career and personal benefits. About two-thirds of the reported relationships involved a direct supervisor who served as a mentor. Mentoring was found to be available to both men and women, however women reported a lesser degree of personal and career benefit than did men.
Ischemic preconditioning procedure induces behavioral deficits in the absence of brain injury

Preconditioning describes a phenomenon whereby a sub-injury inducing insult can protect against a later larger injury. Thus, short-term cerebral ischemia can protect against a prolonged ischemia (ischemic preconditioning). This study examines rats undergoing ischemic preconditioning to test whether preconditioning may cause changes in behavior even though they do not cause an identifiable brain lesion. Rats had a transient (15 minutes) middle cerebral artery occlusion or a sham occlusion. Forelimb placing and forelimb use asymmetry tests were used to assess behavioral deficits. Brain histology, microglia activation, heat shock protein and ferritin levels were also examined. Ischemic preconditioning did not cause brain infarction, but induced behavioral changes. There were no significant differences between ischemic preconditioning and sham rats in the two behavioral tests at day one. However, the ischemic preconditioning group showed impaired forelimb placing at days 3, 7 and 14 (p<0.05). That group also had a significant (p<0.05) behavioral deficit in the forelimb use asymmetry test at days 3 and 7 (but not 14). Our present study demonstrated that a behavioral deficit occurred in ischemic preconditioning. This raises the question of whether induction of protective mechanisms by preconditioning stimuli necessarily involves some form of brain injury, detectable by changes in behavior though not by a lesion. This would be consistent with data suggesting that brain injury can initiate mechanisms potentially favorable to neuroplasticity and neuroprotection.
On the classification of pathways in the auditory midbrain, thalamus, and cortex

Auditory forebrain pathways exhibit several morphological and physiological properties that underlie their specific neurobiological roles in auditory processing. Anatomically, such projections can be distinguished by their terminal size, arborization patterns, and postsynaptic dendritic locations. These structural features correlate with several postsynaptic physiological properties, such as EPSP amplitude, short-term plasticity, and postsynaptic receptor types. Altogether, these synaptic properties segregate into two main classes that are associated with either primarily information-bearing (Class 1) or modulatory (Class 2) roles, and have been used to delineate the principle routes of information flow through the auditory midbrain, thalamus, and cortex. Moreover, these synaptic properties engender as yet unexplored issues regarding the neuronal processing of auditory information, such as the convergent integration and long-term plasticity of auditory forebrain inputs.