cssi/SciSciGPT-SciSciNet huggingface dataset:
High Transcriptional Activity and Diverse Functional Repertoires of Hundreds of Giant Viruses in a Coastal Marine System

ABSTRACT Viruses belonging to the Nucleocytoviricota phylum are globally distributed and include members with notably large genomes and complex functional repertoires. Recent studies have shown that these viruses are particularly diverse and abundant in marine systems, but the magnitude of actively replicating Nucleocytoviricota present in ocean habitats remains unclear. In this study, we compiled a curated database of 2,431 Nucleocytoviricota genomes and used it to examine the gene expression of these viruses in a 2.5-day metatranscriptomic time-series from surface waters of the California Current. We identified 145 viral genomes with high levels of gene expression, including 90 Imitervirales and 49 Algavirales viruses. In addition to recovering high expression of core genes involved in information processing that are commonly expressed during viral infection, we also identified transcripts of diverse viral metabolic genes from pathways such as glycolysis, the TCA cycle, and the pentose phosphate pathway, suggesting that virus-mediated reprogramming of central carbon metabolism is common in oceanic surface waters. Surprisingly, we also identified viral transcripts with homology to actin, myosin, and kinesin domains, suggesting that viruses may use these gene products to manipulate host cytoskeletal dynamics during infection. We performed phylogenetic analysis on the virus-encoded myosin and kinesin proteins, which demonstrated that most belong to deep-branching viral clades, but that others appear to have been acquired from eukaryotes more recently. Our results highlight a remarkable diversity of active Nucleocytoviricota in a coastal marine system and underscore the complex functional repertoires expressed by these viruses during infection. IMPORTANCE The discovery of giant viruses has transformed our understanding of viral complexity. Although viruses have traditionally been viewed as filterable infectious agents that lack metabolism, giant viruses can reach sizes rivalling cellular lineages and possess genomes encoding central metabolic processes. Recent studies have shown that giant viruses are widespread in aquatic systems, but the activity of these viruses and the extent to which they reprogram host physiology in situ remains unclear. Here, we show that numerous giant viruses consistently express central metabolic enzymes in a coastal marine system, including components of glycolysis, the TCA cycle, and other pathways involved in nutrient homeostasis. Moreover, we found expression of several viral-encoded actin, myosin, and kinesin genes, indicating viral manipulation of the host cytoskeleton during infection. Our study reveals a high activity of giant viruses in a coastal marine system and indicates they are a diverse and underappreciated component of microbial diversity in the ocean.
The international governance of refugee work: reflections on the Jordan compact

For the past 70 years, separate international regimes have governed the economic lives of refugees and labor migrants. The United Nations High Commissioner for Refugees (UNHCR) oversees all aspects of refugee resettlement, including livelihoods, while the International Labor Organization (ILO) is charged with addressing the labor rights of migrants. This division has become increasingly problematic as international actors have sought to move refugees into employment arenas from which they have been largely excluded since the end of WWII. This article uses a case study of the 2016 EU-Jordan Compact to illustrate the risks inherent in positioning refugees as workers in the absence of a commitment to a rights-based approach. The Compact was negotiated between the European Commission, the World Bank, and the Government of Jordan, in consultation with the UNHCR; the ILO played no role in crafting the agreement. It sought to place 150,000 Syrians in Jordanian garment export manufacturing jobs, replacing an existing migrant workforce in an industry notorious for low pay and poor conditions. This effort quickly foundered. Instead, large numbers of Syrian refugees have been channeled into informal employment in construction and agriculture in Jordan, where they and migrant co-workers face pervasive violations of labor standards. Without decent work as a central goal, the Compact ultimately concentrated some of the world’s most vulnerable workers in some of its least desirable jobs. To protect refugees and others alongside whom they labor, the article argues, refugee employment initiatives must be accompanied by attention to decent work from the outset. At the international level, this should include a critical role for the ILO, in recognition of its extensive expertise with the establishment and enforcement of labor standards for all workers.
LBT Reveals Large Dust Particles and a High Mass-loss Rate for K2-22 b

The disintegrating planet candidate K2-22 b shows periodic and stochastic transits best explained by an escaping debris cloud. However, the mechanism that creates the debris cloud is unknown. The grain size of the debris as well as its sublimation rate can be helpful in understanding the environment that disintegrates the planet. Here, we present simultaneous photometry with the g band at 0.48 microns and KS band at 2.1 microns using the Large Binocular Telescope. During an event with very low dust activity, we put a new upper limit on the size of the planet of 0.71 earth radii or 4500 km. We also detected a medium-depth transit which can be used to constrain the dust particle sizes. We find that the median particle size must be larger than about 0.5 to 1.0 microns, depending on the composition of the debris. This leads to a high mass loss rate of about 3e8 kg/s that is consistent with hydrodynamic escape models. If they are produced by some alternate mechanism such as explosive volcanism, it would require extraordinary geological activity. Combining our upper limits on the planet size with the high mass loss rate, we find a lifetime of the planet of less than 370 Myr. This drops to just 21 Myr when adopting the 0.02 earth masses predicted from hydrodynamical models.
A Verified, Efficient Embedding of a Verifiable Assembly Language

High-performance cryptographic libraries often mix code written in a high-level language with code written in assembly. To support formally verifying the correctness and security of such hybrid programs, this paper presents an embedding of a subset of x64 assembly language in F* that allows efficient verification of both assembly and its interoperation with C code generated from F*. The key idea is to use the computational power of a dependent type system's type checker to run a verified verification-condition generator during type checking. This allows the embedding to customize the verification condition sent by the type checker to an SMT solver. By combining our proof-by-reflection style with SMT solving, we demonstrate improved automation for proving the correctness of assembly-language code. This approach has allowed us to complete the first-ever proof of correctness of an optimized implementation of AES-GCM, a cryptographic routine used by 90% of secure Internet traffic.
Cost shielding in executive bonus plans

Abstract Executive bonus plans often incorporate performance measures that exclude particular costs—a practice we refer to as “cost shielding.” We predict that boards use cost shielding to mitigate underinvestment and insulate new managers from the costs of prior executives’ decisions. We find evidence that boards use cost shielding to deter underinvestment in intangibles and encourage managers to take advantage of growth opportunities. We also find that cost shielding tends to be elevated for newly-hired executives, and decreases over tenure. Collectively, our results suggest that boards deliberately choose performance metrics that alleviate agency conflicts.
Policy or Partisanship in the United Kingdom? Quasi-Experimental Evidence from Brexit

Are voters motivated by policy preferences or partisan identities? In this paper, we argue that the British Conservative Party’s sudden change in Brexit policy (following the surprising result of t...
Iterated differences sets, Diophantine approximations and applications

Abstract Let v be an odd real polynomial (i.e. a polynomial of the form ∑ j = 1 l a j x 2 j − 1 ). We utilize sets of iterated differences to establish new results about sets of the form R ( v , ϵ ) = { n ∈ N | ‖ v ( n ) ‖ ϵ } where ‖ ⋅ ‖ denotes the distance to the closest integer. We then apply the new Diophantine results to obtain applications to ergodic theory and combinatorics. In particular, we obtain a new characterization of weakly mixing systems as well as a new variant of Furstenberg-Sarkozy theorem.
Increased ACTL6A Occupancy within mSWI/SNF Chromatin Remodelers Drives Human Squamous Cell Carcinoma

Mammalian SWI/SNF (BAF) chromatin remodelers play dosage-sensitive roles in many human malignancies and neurologic disorders. The gene encoding the BAF subunit, ACTL6A, is amplified at an early stage in the development of squamous cell carcinomas (SCCs), but its oncogenic role remains unclear. Here we demonstrate that ACTL6A overexpression leads to its stoichiometric assembly into BAF complexes and drives its interaction and engagement with specific regulatory regions in the genome. In normal epithelial cells, ACTL6A was sub-stoichiometric to other BAF subunits. However, increased ACTL6A levels by ectopic expression or in SCC cells led to near-saturation of ACTL6A within BAF complexes. Increased ACTL6A occupancy enhanced polycomb opposition over the genome activating SCC genes and also enhanced the recruitment of transcription factor TEAD with its co-activator YAP, promoting their chromatin binding and enhancer accessibility. Both of these mechanisms appeared to be critical and function as a molecular AND gate for SCC initiation and maintenance, thereby explaining the specificity of the role of ACTL6A amplification in SCCs.
Deep Neural Network for 3D Surface Segmentation based on Contour Tree Hierarchy

Given a 3D surface defined by an elevation function on a 2D grid as well as non-spatial features observed at each pixel, the problem of surface segmentation aims to classify pixels into contiguous classes based on both non-spatial features and surface topology. The problem has important applications in hydrology, planetary science, and biochemistry but is uniquely challenging for several reasons. First, the spatial extent of class segments follows surface contours in the topological space, regardless of their spatial shapes and directions. Second, the topological structure exists in multiple spatial scales based on different surface resolutions. Existing widely successful deep learning models for image segmentation are often not applicable due to their reliance on convolution and pooling operations to learn regular structural patterns on a grid. In contrast, we propose to represent surface topological structure by a contour tree skeleton, which is a polytree capturing the evolution of surface contours at different elevation levels. We further design a graph neural network based on the contour tree hierarchy to model surface topological structure at different spatial scales. Experimental evaluations based on real-world hydrological datasets show that our model outperforms several baseline methods in classification accuracy.
Commutator-free Lie group methods with minimum storage requirements and reuse of exponentials

A new format for commutator-free Lie group methods is proposed based on explicit classical Runge-Kutta schemes. In this format exponentials are reused at every stage and the storage is required only for two quantities: the right hand side of the differential equation evaluated at a given Runge-Kutta stage and the function value updated at the same stage. The next stage of the scheme is able to overwrite these values. The result is proven for a 3-stage third order method and a conjecture for higher order methods is formulated. Five numerical examples are provided in support of the conjecture. This new class of structure-preserving integrators has a wide variety of applications for numerically solving differential equations on manifolds.
Computing the Union Join and Subset Graph of Acyclic Hypergraphs in Subquadratic Time

We investigate the two problems of computing the union join graph as well as computing the subset graph for acyclic hypergraphs and their subclasses. In the union join graph G of an acyclic hypergraph H, each vertex of G represents a hyperedge of H and two vertices of G are adjacent if there exits a join tree T for H such that the corresponding hyperedges are adjacent in T. The subset graph of a hypergraph H is a directed graph where each vertex represents a hyperedge of H and there is a directed edge from a vertex u to a vertex v if the hyperedge corresponding to u is a subset of the hyperedge corresponding to v.
Activity-dependent modulation of synapse-regulating genes in astrocytes

Astrocytes regulate the formation and function of neuronal synapses via multiple signals; however, what controls regional and temporal expression of these signals during development is unknown. We determined the expression profile of astrocyte synapse-regulating genes in the developing mouse visual cortex, identifying astrocyte signals that show differential temporal and layer-enriched expression. These patterns are not intrinsic to astrocytes, but regulated by visually evoked neuronal activity, as they are absent in mice lacking glutamate release from thalamocortical terminals. Consequently, synapses remain immature. Expression of synapse-regulating genes and synaptic development is also altered when astrocyte signaling is blunted by diminishing calcium release from astrocyte stores. Single-nucleus RNA sequencing identified groups of astrocytic genes regulated by neuronal and astrocyte activity, and a cassette of genes that show layer-specific enrichment. Thus, the development of cortical circuits requires coordinated signaling between astrocytes and neurons, highlighting astrocytes as a target to manipulate in neurodevelopmental disorders.
Interactive Machine Comprehension with Dynamic Knowledge Graphs

Interactive machine reading comprehension (iMRC) is machine comprehension tasks where knowledge sources are partially observable. An agent must interact with an environment sequentially to gather necessary knowledge in order to answer a question. We hypothesize that graph representations are good inductive biases, which can serve as an agent’s memory mechanism in iMRC tasks. We explore four different categories of graphs that can capture text information at various levels. We describe methods that dynamically build and update these graphs during information gathering, as well as neural models to encode graph representations in RL agents. Extensive experiments on iSQuAD suggest that graph representations can result in significant performance improvements for RL agents.
Dimsyl Anion Enables Visible-Light-Promoted Charge Transfer in Cross-Coupling Reactions of Aryl Halides

A simple and mild methodology is reported for visible-light-promoted synthesis of unsymmetrical chalconides ena- bled by dimsyl anion in the absence of transition-metals or photoredox catalysts. The cross-coupling reaction between aryl halides and diaryl dichalconides proceeds in good to excellent yields with electron-rich, electron-poor, and heteroaromatic moieties. Mechanistic investigations using UV−Vis spectroscopy, time-dependent density functional theory (DFT) calculations, and control reactions suggest that dimsyl anion forms an electron-donor-acceptor (EDA) complex capable of absorbing blue light, leading to a charge transfer responsible for generation of aryl radicals from aryl halides. This previously unreported mechanistic pathway may be applied to other light-induced transformations performed in DMSO in the presence of bases and aryl halides.
Good Formal Structures for Flat Meromorphic Connections, III: Irregularity and Turning Loci

Given a formal flat meromorphic connection over an excellent scheme over a field of characteristic zero, in a previous paper we established existence of good formal structures and a good Deligne-Malgrange lattice after suitably blowing up. In this paper, we reinterpret and refine these results by introducing some related structures. We consider the turning locus, which is the set of points at which one cannot achieve a good formal structure without blowing up. We show that when the polar divisor has normal crossings, the turning locus is of pure codimension 1 within the polar divisor, and hence of pure codimension 2 within the full space; this had been previously established by Andre in the case of a smooth polar divisor. We also construct an irregularity sheaf and its associated b-divisor, which measure irregularity along divisors on blowups of the original space; this generalizes another result of Andre on the semicontinuity of irregularity in a curve fibration. One concrete consequence of these refinements is a process for resolution of turning points which is functorial with respect to regular morphisms of excellent schemes; this allows us to transfer the result from schemes to formal schemes, complex analytic varieties, and nonarchimedean analytic varieties.
Stability and molecular pathways to the formation of spin defects in silicon carbide.

Spin defects in wide-bandgap semiconductors provide a promising platform to create qubits for quantum technologies. Their synthesis, however, presents considerable challenges, and the mechanisms responsible for their generation or annihilation are poorly understood. Here, we elucidate spin defect formation processes in a binary crystal for a key qubit candidate—the divacancy complex (VV) in silicon carbide (SiC). Using atomistic models, enhanced sampling simulations, and density functional theory calculations, we find that VV formation is a thermally activated process that competes with the conversion of silicon (VSi) to carbon monovacancies (VC), and that VV reorientation can occur without dissociation. We also find that increasing the concentration of VSi relative to VC favors the formation of divacancies. Moreover, we identify pathways to create spin defects consisting of antisite-double vacancy complexes and determine their electronic properties. The detailed view of the mechanisms that underpin the formation and dynamics of spin defects presented here may facilitate the realization of qubits in an industrially relevant material. Understanding the mechanism of formation of solid-state spin defects underpins their future applications in quantum technologies. Here, the authors use a combination of ab initio molecular dynamics, enhanced sampling, and density functional theory to clarify the formation process of spin defects in silicon carbide.
Interval timing and midfrontal delta oscillations are impaired in Parkinson's disease patients with freezing of gait.

Gait abnormalities and cognitive dysfunction are common in patients with Parkinson's disease (PD) and get worse with disease progression. Recent evidence has suggested a strong relationship between gait abnormalities and cognitive dysfunction in PD patients and impaired cognitive control could be one of the causes for abnormal gait patterns. However, the pathophysiological mechanisms of cognitive dysfunction in PD patients with gait problems are unclear. Here, we collected scalp electroencephalography (EEG) signals during a 7-s interval timing task to investigate the cortical mechanisms of cognitive dysfunction in PD patients with (PDFOG +, n = 34) and without (PDFOG-, n = 37) freezing of gait, as well as control subjects (n = 37). Results showed that the PDFOG + group exhibited the lowest maximum response density at around 7 s compared to PDFOG- and control groups, and this response density peak correlated with gait abnormalities as measured by FOG scores. EEG data demonstrated that PDFOG + had decreased midfrontal delta-band power at the onset of the target cue, which was also correlated with maximum response density and FOG scores. In addition, our classifier performed better at discriminating PDFOG + from PDFOG- and controls with an area under the curve of 0.93 when midfrontal delta power was chosen as a feature. These findings suggest that abnormal midfrontal activity in PDFOG + is related to cognitive dysfunction and describe the mechanistic relationship between cognitive and gait functions in PDFOG + . Overall, these results could advance the development of novel biosignatures and brain stimulation approaches for PDFOG + .
Corpus-based Open-Domain Event Type Induction

Traditional event extraction methods require predefined event types and their corresponding annotations to learn event extractors. These prerequisites are often hard to be satisfied in real-world applications. This work presents a corpus-based open-domain event type induction method that automatically discovers a set of event types from a given corpus. As events of the same type could be expressed in multiple ways, we propose to represent each event type as a cluster of pairs. Specifically, our method (1) selects salient predicates and object heads, (2) disambiguates predicate senses using only a verb sense dictionary, and (3) obtains event types by jointly embedding and clustering pairs in a latent spherical space. Our experiments, on three datasets from different domains, show our method can discover salient and high-quality event types, according to both automatic and human evaluations.
Task Space Planning With Complementarity Constraint-Based Obstacle Avoidance

In this paper, we present a task space-based local motion planner that incorporates collision avoidance and constraints on end-effector motion during the execution of a task. Our key technical contribution is the development of a novel kinematic state evolution model of the robot where the collision avoidance is encoded as a complementarity constraint. We show that the kinematic state evolution with collision avoidance can be represented as a Linear Complementarity Problem (LCP). Using the LCP model along with Screw Linear Interpolation (ScLERP) in SE(3), we show that it may be possible to compute a path between two given task space poses by directly moving from the start to the goal pose, even if there are potential collisions with obstacles. The scalability of the planner is demonstrated with experiments using a physical robot. We present simulation and experimental results with both collision avoidance and task constraints to show the efficacy of our approach.
Adaptive control for tracking and disturbance attenuation for SISO linear systems with repeated noisy measurements

We address the worst-case adaptive controller design for single-input linear systems with repeated noisy measurements of a particular linear combination of the state variables to achieve asymptotic tracking and disturbance attenuation. Using the design paradigm outlined in, we obtained a class of single-input multiple-output adaptive controllers in closed-form with strong robustness properties. It is shown that the closed-loop system is totally stable with respect to the disturbance and the initial condition. Furthermore, when the exogenous disturbance has bounded energy and is uniformly bounded, the closed-loop system achieves asymptotic tracking of the reference trajectory. This design is further compared with certain single-input single-output design for trade-offs.
Implementing Scalable Parallel Search Algorithms for Data-Intensive Applications

Scalability is a critical issue in the design of parallel software for large-scale search problems. Previous research has not addressed this issue for data-intensive applications. We describe the design of a library for parallel search that focuses on efficient data and search tree management for such applications in distributed computing environments.
Dual-axis vapor cell for simultaneous laser frequency stabilization on disparate optical transitions

We have developed a dual-axis ytterbium (Yb) vapor cell and used it to simultaneously address the two laser cooling transitions in Yb at wavelengths 399 nm and 556 nm, featuring the disparate linewidths of 2π × 29 MHz and 2π × 182 KHz, respectively. By utilizing different optical paths for the two wavelengths, we simultaneously obtain comparable optical densities suitable for saturated absorption spectroscopy for both the transitions and keep both the lasers frequency stabilized over several hours. We demonstrate that by appropriate control of the cell temperature profile, two atomic transitions differing in relative strength across a large range of over three orders of magnitude can be simultaneously addressed, making the device adaptable to a variety of spectroscopic needs. We also show that our observations can be understood with a simple theoretical model of the Yb vapor.
Clinical use of psychotherapeutic drugs.

We know little of the pathogenesis of anxiety, depression and psychosis or how psychotherapeutic drugs relieve them, but drugs may figure in the total psychiatric treatment. Antianxiety drugs may be most effective when used in unconventional ways. Some drugs considered as primarily antianxiety or antipsychotic agents may be useful in specific depressive syndromes. Antipsychotic drugs provide novel treatment of undoubted efficacy. However, older drugs and methods, such as phenobarbital and electroshock therapy, should not be neglected.
In-channel micromechanical drag flow sensor with electronic readout

We report an in-channel microbeam flow sensor with electronic readout that utilizes drag forces to measure flow rates at low Reynolds numbers. The flow sensor converts the moment of a bent beam into differential strain across a Wheatstone-bridge under the anchor of the beam. The flowsensor has sensitivities of 0.5 /spl mu/VN/(nl/s). Given the thermal noise of the Wheatstone-bridge to be 80nV//spl radic/Hz, the flow sensor can measure flow rates as low as 4.2 nl/min.
Russia Faces Depopulation? Dynamics of Population Decline

Between 1992 and 1993 Russia's population declined, as it has in every succeeding year. This has been viewed as a population disaster, related to high adult male mortality and deterioration of the health care system. Some see a substantially depopulated Russia in the future. However, the prospect of long-term population decline is completely due to recent declines in fertility. High adult male mortality, although a cause of great concern, does not contribute to the chance of long-term population decline. Projections of the future population of Russia depend upon the exact fertility assumptions used. Based on the example of fertility in the United States in the Great Depression and the Baby Boom following World War II, the future depopulation of Russia is far from certain.
Arrest of afferent axon extension by target neurons in vitro is regulated by the NMDA receptor

Cerebellar granule neurons in vitro specifically arrest the extension of their appropriate presynaptic axons, mossy fibers. This "stop-growing signal" may be an essential step in the formation and specificity of synapses. Here, we have tested whether ionotropic glutamate receptors are involved in the stop-growing signal. When explants of basilar pontine nuclei, a mossy fiber source, were cultured on granule neurons, most pontine neurites terminated <200 microm from their explant of origin, a criterion for the stop-growing signal. In contrast, treatment with the NMDA antagonist D(-)-2-amino-5-phosphonopentanoic acid (D-AP5) greatly increased the number of pontine neurites extending beyond 300 microm, whereas treatment with NMDA reduced the number of pontine neurites extending beyond 200 microm. A non-NMDA agonist (AMPA) and antagonist (6-cyano-7-nitroquinoxaline-2,3-dione) did not alter pontine neurite lengths. None of these agents affected neurite outgrowth from pontine explants in the absence of granule neurons, nor did any agent affect the survival of granule neurons. These results indicate that NMDA and D-AP5 specifically perturb an interaction between axons and target cells necessary for the stop-growing signal, and that NMDA receptors are critical for the development of a major cerebellar afferent system. These findings also suggest that NMDA-sensitive refinement of axon arbors during later development may involve the direct regulation of axon extension by target neurons.
A three-level graph based interactive volume segmentation system

We present a new hierarchical graph representation for volume data as well as its associated operations to enable interactive feature segmentation for high-resolution volume data. Our method constructs a low-resolution graph which represents a coarser resolution of the data. This graph enables the user to interactively sample and edit a feature of interest by drawing strokes on data slices. A subgraph representing the feature is derived with a growing process, and is used to extract the high-resolution version of the feature from the original volume data by performing an automatic mapping and refinement procedure. Our three-level, graph-based approach overcomes partial volume effects that are introduced by downsampling the volume data, and enables interactive segmentation of fine features. We demonstrate the effectiveness of this approach with several challenging 3D segmentation applications.
Modeling Dynamic Biological Systems

Models help us understand the dynamics of real-world processes by using the computer to mimic the actual forces that are known or assumed to result in a system's behavior. This book does not require a substantial background in mathematics or computer science.
The Critical Path from Tissue Slices to Surgical Simulation: What Do Surgeons Want?

Three themes: Building 3D Geometric Models from Slice Databases Segmentation and Extraction, and Virtual and Physical Modeling Creating an Educational Context with Information Frames The Hidden Curriculum of Surgery: Simulating Manipulations with Instruction Frames Building 3D geometric models from slice databases requires an aligned, (registered) volumetric dataset. Initial visualization of the anatomic region of surgical interest (AROSI), followed by segmentation and extraction of selected structures in each slice produces 2D masks for each anatomic structure. These are stacked to create 3D virtual anatomic models, either surface or volumetric, which can be transformed into physical 3D models by finite element, or other physical modeling algorithms. The methods for building 3D models will be discussed. Examples are: 1. the Lawrence Berkeley National Labs frog 2. the Stanford Visible Female (pelvis) segmentation is the selection of desired structures, and /or suppression of undesired structures prior to rendering extraction of selected structures in each slice allows for visualization of several types: 3D volumetric visualization and analysis can be done from unreconstructed images, reformated planes, curved planar reformatting, surface and volume rendering, maximum intensity projection, and shaded surface displays. transforming 3D volumetric models into physical models by finite element, or other physical modeling algorithms provides opportunity for deformations, incisions, etc. an application of such models, instrumented with accelerometers and pressure sensors is the crash testing of Cyber Dummies
Optimizing Outcomes During Left Main Percutaneous Coronary Intervention With Intravascular Ultrasound and Fractional Flow Reserve: The Current State of Evidence

Percutaneous coronary intervention (PCI) is an evolving indication for the treatment of unprotected left main coronary arterial (UMLCA) stenoses in selected individuals. Intravascular ultrasound (IVUS)-guided PCI within the epicardial coronary tree has been shown to improve acute procedural results and subsequent clinical outcomes. Similarly, fractional flow reserve (FFR) is rapidly gaining popularity as a means to guide the coronary interventionalist to embark upon a “physiological-based” revascularization strategy. In light of the emergence of PCI for ULMCA stenoses, the lack of randomized trials has meant that there are no systematic guidelines that advocate the routine use of these adjunctive imaging techniques to optimize procedural and clinical outcomes. Given the potential dire clinical consequences of procedural failure during ULMCA PCI, in this review we systematically address the current level of evidence for the use of FFR and IVUS during the assessment for and undertaking of PCI for ULMCA stenoses. In lieu of the current available level of evidence, we recommend the use of FFR for the assessment of (angiographic indeterminate) isolated ostial or midshaft left main coronary arterial (LMCA) stenoses in patients who are considered more appropriate candidates for coronary arterial bypass grafting. In those patients with distal/bifurcation LMCA lesions and in those with diffuse/distal coronary arterial disease, we strongly recommend the liberal use of IVUS. Furthermore, in those patients considered likely candidates for ULMCA PCI, IVUS remains crucial for assessing the degree of lumen compromise and the extent, distribution, and morphology of plaque as well as for the immediate postprocedural quantification of stent deployment.
Metformin for Prevention of Type 2 Diabetes

OBJECTIVE:To evaluate evidence from the medical literature that metformin is effective in preventing type 2 diabetes.DATA SOURCES:Primary literature was accessed via a MEDLINE search (1966—December 2003) using the terms metformin, type 2 diabetes, and prevention.DATA SYNTHESIS:Two studies evaluated metformin's potential to prevent type 2 diabetes, finding that metformin maintained or reduced fasting blood glucose in non-diabetics. Recently, a large study by the Diabetes Prevention Program showed that metformin may reduce the incidence of diabetes. Researchers compared lifestyle changes, metformin therapy, and placebo groups. They found that both lifestyle changes (58%) and metformin therapy (31%) significantly reduced the occurrence of type 2 diabetes versus placebo.CONCLUSIONS:These studies provide evidence that metformin may reduce the occurrence of type 2 diabetes. Because long-term efficacy has not been determined, further studies are needed.
The challenges of designing lab exercises for a curriculum in computer security

Increasing awareness of the vulnerabilities of computer systems has led to the introduction of several programs in computer security. Most of these programs are meant to attract graduate students. Southern Oregon University has recently started a new undergraduate track in computer security and information assurance. In this paper we describe the development of lab exercises geared toward such a curriculum. The process begins with the curriculum itself and the lab - designing one that mirrors an actual enterprise and allows machines to be "attacked" while protecting the campus and external networks. The next step is designing assignments that model real-world situations like finding vulnerabilities in a system and using them to gain access to the system. The final step is designing larger exercises or projects that can be undertaken at the capstone level or at the graduate level. The paper describes ongoing efforts as well as future plans for such exercises.
Influence of topsoil removal and fertilizer application on peanut yields from an Indonesian Ultisol.

Experiments were conducted on a tropical Ultisol in west central Sumatra, Indonesia, to evaluate the effects of topsoil removal and the subsequent application of phosphorus and potassium fertilizers, and calcium lime, on crop productivity. Peanut (Arachis hypogaea L.) yields and total above-ground biomass production were determined in field plots and potted soils from which 0, 3, 7 and 15 cm of topsoil had been removed. The removal of 3 cm of topsoil, which was equivalent to the entire A-horizon resulted in a significant reduction in peanut yields and above-ground biomass in both field and potted soils. No significant yield differences in peanut yields or biomass were observed between] treatments from which ⩾3 cm of topsoil had been removed. The application of fertilizers and lime restored peanut yields to levels observed in unfertilized soils from which topsoil had not been removed. However, the use of off-farm inputs was economically unfeasible for most hillside farmers in the research area.
Cotunneling spectroscopy in few-electron quantum dots

Few-electron quantum dots are investigated in the regime of strong tunneling to the leads. Inelastic cotunneling is used to measure the two-electron singlet-triplet splitting above and below a magnetic field driven singlet-triplet transition. Evidence for a nonequilibrium two-electron singlet-triplet Kondo effect is presented. Cotunneling allows orbital correlations and parameters characterizing entanglement of the two-electron singlet ground state to be extracted from dc transport.
Morphology of metazoan circulatory systems

The majority of large, bilaterally-symmetric animals possess two structurally distinct systems of internal fluid transport, the coelomic circulatory system and the blood vascular system (BVS). The coelomic circulatory system is generally situated laterally, lined by a continuous layer of mesodermally-derived cells and moves fluid with cilia or body wall muscles. The BVS occurs in extracellular matrix with the principal vessels situated dorsally and ventrally. The vessels are typically unlined by cells. Fluid is propelled by contraction of overlying muscle cells. Co-occurrence of two systems of internal fluid transport is explained by a segmentation hypothesis: Most large, triploblastic animals are segmented with at least two or three fluid-filled compartments separated by septal bulkheads. Because exchange surfaces (gas, nutrient) are regionally restricted, selective pressure favors a fluid transport system that bridges septal bulkheads. The BVS fulfills this requirement because it is situated in extracellular matrix that is non-cellular and continuous throughout organisms. A survey of animals indicates that all segmented taxa possess a BVS, except Sipuncula, where compensation sacs function as BVS analogues. Loss of the BVS in Hirudinea and other annelids is correlated with the disappearance of septa. Funicular vessels in Bryozoa are compared with BVS in other lophophorates. The fluid transport system of Nemertini and some platyhelminths is shown to conform to the definition of a coelomic circulatory system. This investigation supports Liwanow's proposition that the BVS evolved as the progressive modification of extracellular matrix in triploblastic animals. Evolution of coelomic circulatory systems is unresolved.
Current saturation in submicrometer graphene transistors with thin gate dielectric: experiment, simulation, and theory.

Recently, graphene field-effect transistors (FET) with cutoff frequencies (fT) between 100 and 300 GHz have been reported; however, the devices showed very weak drain current saturation, leading to an undesirably high output conductance (gds= dIds/dVds). A crucial figure-of-merit for analog/RF transistors is the intrinsic voltage gain (gm/gds) which requires both high gm (primary component of fT) and low gds. Obtaining current saturation has become one of the key challenges in graphene device design. In this work, we study theoretically the influence of the dielectric thickness on the output characteristics of graphene FETs by using a surface-potential-based device model. We also experimentally demonstrate that by employing a very thin gate dielectric (equivalent oxide thickness less than 2 nm), full drain current saturation can be obtained for large-scale chemical vapor deposition graphene FETs with short channels. In addition to showing intrinsic voltage gain (as high as 34) that is comparable to commer...
Tests of long-run Purchasing Power Parity using alternative methodologies☆

Abstract This study examines the empirical evidence on Purchasing Power Parity (PPP) for Canada and Japan vis-a-vis the United States for the fixed and flexible exchange rate eras by comparing results from the Perron (1989) and Dickey-Fuller (1981) methodologies. We address the potentially significant criticism of existing studies—that unit root tests have notoriously low power against alternative hypotheses. The Perron (1989) methodology offers an alternative: that a series is stationary about a structural break. Our findings substantiate those more recent studies that rely on unit root test procedures but that have ignored the bias to their finding caused by structural breaks.
Necessity, contingency, and punishment

IN THIS discussion we wish to examine a commonly held view of moral responsibility which might be called the Punishment Theory.' According to the Punishment Theory one is morally responsible for an action if and only if one is modifiable by punishment. A wrongdoer is morally responsible for his action if punishment will influence him to avoid such actions in the future or if it would have affected his choice to do wrong. This view has two advantages. It enables one to maintain that determinism and moral responsibility are compatible notions, for the fact that a person was determined does not itself negate the possibility of his alteration by punishment. Furthermore, on this view the question of a man's responsibility is settled by ordinary empirical procedures. No vague questions arise about his metaphysical contra-causal powers. Unfortunately, the view is untenable. Rather than suggesting counterexamples to this position as a critic such as C. A. Campbell does,2 we propose to consider the basic confusion which makes it possible to generate counter-examples. It is generally conceded that a necessary condition for moral responsibility is that a person who did wrong could have done otherwise, although, of course, the analysis of this phrase is problematic. Proponents of the Punishment Theory do not usually discuss in detail the relation of this requirement to the issue of punishment, though none of them deny that it is a requirement for moral responsibility. If the theory is to be satisfactory, however, it must give some account of the connection between punishment and the condition that an individual could have done otherwise. The basic difficulty is this. The connection between the fact that a certain person can be (or could have been) affected by punishment and the fact that he could have done otherwise is a contingent one. It may be granted that the connection in fact is often present. Individuals who we feel clearly could not have done otherwise, e.g., compulsives, and whom we thereby excuse from moral responsibility are also persons whose behavior does not seem to be affected by punishment. Thus, the fact that punishing a certain type of offender has no effect on his behavior is sometimes good evidence of the compulsive character of his crime, i.e., that he couldn't help doing it. But however reliable an indicator the fact that a man won't be
Atmospheric deposition of nitrate and its transport to the Apalachicola Bay estuary in Florida

A comparison of fluxes of ten dissolved constituents of rain water and river water has been carried out for the watershed of the Apalachicola River in order to estimate the magnitude of nitrate contribution from the atmosphere to surface water that may flow to the Apalachicola Bay estuary. The comparison is based on statistical analysis of both atmospheric and fiver water monitoring data: weekly rain water chemical data from the National Acid Deposition Program (NADP) for five sites within the watershed area, from 1978–84 until late 1989, and less frequent river water chemical data from the U.S. Geological Survey for one site ai Chattahoochee, Florida, from 1965 until late 1989. The means and standard errors of the fluxes from the atmosphere and in the river flow were determined. As a measure of correlations between different ionic concentrations in the rain and river water data sets, factor analysis was used to account for data variance by a sum of principal components according to a linear mixing model. By comparing the compositions and magnitudes of these components, judgments could be made concerning the importance of atmospheric deposition as a source of nitrate in the watershed as well as of chemical transformations and possible loss of nitrate during its residence in the watershed and transport to the estuary. Although surface sources of N and extent of loss to the atmosphere by denitrification have not yet been quantitatively determined, atmospheric deposition to the watershed appears to be sufficient to account for essentially all the dissolved nitrate and ammonium and total organic N flow in the river. After deposition most of the nitrate may be transformed to other chemical forms during the flow, except possibly under high flow conditions that mainly occur in winter. However, either nitrate or the other forms could, with high efficiency, reach the estuary and be available for its marine biological processes.
Nanoscience and technology: the next revolution in the Earth sciences

Nanoscience and technology are not exactly new, but nevertheless rapidly expanding fields that are providing revolutions in all sciences on the scale of what genomics and proteomics have done in recent years for the biological sciences. Nanoscience is based on the fact that properties of materials change as a function of the physical dimension of that material, and nanotechnology takes advantage of this by applying selected property modifications of this nature to some beneficial endeavor. The prefix 'nano' is used because the property dependence on physical size is generally observed close to the nanoscale, somewhere around 10 39 m. The dimensions at which changes are observed depend on the specific material and the property in question, as well as which of the three dimensions are restricted in real space (e.g. small particles vs. thin films vs. 'one-dimensional' phases). Properties change in these confined spaces because the electronic structure (i.e. the distribution of electron energies) of the material is modified here in the gray area between the bulk and atomistic/molecular realms, or equivalently between the continuum and strictly quantum domains. Earth materials with at least one dimension in the nanorange are essentially ubiquitous. Many have been known for several decades and more are being discovered all the time. But the scientific emphasis has now shifted to that of measuring, understanding and ultimately predicting the property changes from the bulk to nanodomains, and to the understanding of the significant ways that Earth processes are affected by these changes. In addition, where possible, Earth scientists are using nanoscience to develop nanotechnology that should play important roles in Earth sustainability issues of the future. 6 2002 Elsevier Science B.V. All rights reserved.