cssi/SciSciGPT-SciSciNet huggingface dataset:
Probabilistic Models for Unified Collaborative and Content-Based Recommendation in Sparse-Data Environments

Recommender systems leverage product and community information to target products to consumers. Researchers have developed collaborative recommenders, content-based recommenders, and a few hybrid systems. We propose a unified probabilistic framework for merging collaborative and content-based recommendations. We extend Hofmarm's (1999) aspect model to incorporate three-way co-occurrence data among users, items, and item content. The relative influence of collaboration data versus content data is not imposed as an exogenous parameter, but rather emerges naturally from the given data sources. However, global probabilistic models coupled with standard EM learning algorithms tend to drastically overfit in the sparsedata situations typical of recommendation applications. We show that secondary content information can often be used to overcome sparsity. Experiments on data from the Researchlndex library of Computer Science publications show that appropriate mixture models incorporating secondary data produce significantly better quality recommenders than k-nearest neighbors (k-NN). Global probabilistic models also allow more general inferences than local methods like k-NN.
Therapeutic devices for epilepsy

Therapeutic devices provide new options for treating drug-resistant epilepsy. These devices act by a variety of mechanisms to modulate neuronal activity. Only vagus nerve stimulation (VNS), which continues to develop new technology, is approved for use in the United States. Deep brain stimulation of anterior thalamus for partial epilepsy recently was approved in Europe and several other countries. Responsive neurostimulation, which delivers stimuli to 1 or 2 seizure foci in response to a detected seizure, recently completed a successful multicenter trial. Several other trials of brain stimulation are in planning or underway. Transcutaneous magnetic stimulation (TMS) may provide a noninvasive method to stimulate cortex. Controlled studies of TMS are split on efficacy, which may depend on whether a seizure focus is near a possible region for stimulation. Seizure detection devices in the form of shake detectors via portable accelerometers can provide notification of an ongoing tonic-clonic seizure, or peace of mind in the absence of notification. Prediction of seizures from various aspects of electroencephalography (EEG) is in early stages. Prediction appears to be possible in a subpopulation of people with refractory seizures, and a clinical trial of an implantable prediction device is underway. Cooling of neocortex or hippocampus reversibly can attenuate epileptiform EEG activity and seizures, but engineering problems remain in its implementation. Optogenetics is a new technique that can control excitability of specific populations of neurons with light. Inhibition of epileptiform activity has been demonstrated in hippocampal slices, but use in humans will require more work. In general, devices provide useful palliation for otherwise uncontrollable seizures, but with a different risk profile than with most drugs. Optimizing the place of devices in therapy for epilepsy will require further development and clinical experience.
Virtually Haken fillings and semi-bundles

Suppose thatM is a fibered three-manifold whose fiber is a surface of positive genus with one boundary component. Assume that M is not a semi-bundle. We show that infinitely many fillings of M along ∂M are virtually Haken. It follows that infinitely many Dehn-surgeries of any non-trivial knot in the three-sphere are virtually Haken.
Perioperative Epoetin Alfa Increases Red Blood Cell Mass and Reduces Exposure to Transfusions: Results of Randomized Clinical Trials

To avoid the inherent risk of complications associated with perioperative allogeneic transfusion, preoperative autologous blood donation (PAD) is frequently employed by patients undergoing major elective surgical procedures. However, many patients are unable to donate a sufficient quantity of blood prior to surgery. Recent studies have shown that epoetin alfa (Procrit; Ortho-Biotech, Raritan, NJ) effectively increases red blood cell (RBC) mass when administered preoperatively and decreases the requirement for allogeneic transfusion. These studies also demonstrated that patients with baseline hemoglobin levels ranging from 10 to 13 g/dL have the highest risk for requiring allogeneic transfusions and appear to achieve the greatest benefit from epoetin alfa treatment. We evaluated several dosing regimens and schedules for perioperative epoetin alfa administration. In our initial study, the comparative efficacy of three different epoetin alfa regimens was assessed by hemoglobin concentration, hematocrit, and absolute reticulocyte counts. In addition, we analyzed the effect of accelerated erythropoiesis on iron indices and individual RBC hemoglobin content. Our study demonstrated that epoetin alfa is safe and effective in increasing RBC mass; however, iron stores considered sufficient for basal erythropoiesis may not optimally support the accelerated RBC production associated with epoetin alfa therapy. In a subsequent randomized multicenter trial, we compared weekly epoetin alfa dosing to daily dosing in patients undergoing elective major orthopedic surgery. The results of this study indicated that administering epoetin alfa on a weekly schedule for several weeks prior to surgery may be at least as effective and more convenient than perioperative daily epoetin alfa dosing.
Energy-efficient channel estimation in MIMO systems

The emergence of MIMO communications systems as practical high-data-rate wireless communications systems has created several technical challenges to be met. On the one hand, there is potential for enhancing system performance in terms of capacity and diversity. On the other hand, the presence of multiple transceivers at both ends has created additional cost in terms of hardware and energy consumption. For coherent detection as well as to do optimization such as water filling and beamforming, it is essential that the MIMO channel is known. However, due to the presence of multiple transceivers at both the transmitter and receiver, the channel estimation problem is more complicated and costly compared to a SISO system. Several solutions have been proposed to minimize the computational cost, and hence the energy spent in channel estimation of MIMO systems. We present a novel method of minimizing the overall energy consumption. Unlike existing methods, we consider the energy spent during the channel estimation phase which includes transmission of training symbols, storage of those symbols at the receiver, and also channel estimation at the receiver. We develop a model that is independent of the hardware or software used for channel estimation, and use a divide-and-conquer strategy to minimize the overall energy consumption.
Multivariate dependence and genetic networks inference

A critical task in systems biology is the identification of genes that interact to control cellular processes by transcriptional activation of a set of target genes. Many methods have been developed that use statistical correlations in high-throughput data sets to infer such interactions. However, cellular pathways are highly cooperative, often requiring the joint effect of many molecules. Few methods have been proposed to explicitly identify such higher-order interactions, partially due to the fact that the notion of multivariate statistical dependence itself remains imprecisely defined. The authors define the concept of dependence among multiple variables using maximum entropy techniques and introduce computational tests for their identification. Synthetic network results reveal that this procedure uncovers dependencies even in undersampled regimes, when the joint probability distribution cannot be reliably estimated. Analysis of microarray data from human B cells reveals that third-order statistics, but not second-order ones, uncover relationships between genes that interact in a pathway to cooperatively regulate a common set of targets.
Telecommunications policy and the pleasure principle.

Abstract Most serious discussion of telecommunications policy is governed by a utilitarian framework in which the success of communications networks is measured by some criterion of productivity. This exclusive emphasis creates undesirable rigidities in large communications systems upon which industrialized societies are so dependent. An analysis of productivity constraints on the social flexibility of existing networks is offered in support of an argument for deliberately building playfulness, in line with certain modest proposals, into the organization of emerging networks of communication.
A two-phase procedure for the study of computer network reliability in automated manufacturing systems

Abstract This paper presents a mathematical model for analyzing computer networks in production systems. The manufacturing facility, which is considered to be the main part of a production system is controlled by a computer network. Every station within a production system is assumed to have a computer and a network interface unit (NIU) as part of the overall computer network. For the system to remain operational, the computer network along with the manufacturing facilities should be extremely reliable. In this paper, we studied the reliability of the former, the computer network. The manufacturing facility is assumed to be reliable. Since every station must be operational for the whole system to function, failure in any network unit (computer of NIU) will halt the system production. For such systems the topology is logically equivalent to that of a system whose stations are connected in series. Hence, series reliability formulae is appropriate for these systems. In other systems, back-up (or stand-by) units are added to the computer and/or to the NIU to enhance the reliability. We consider our model to be a generic one because the reliability analysis it uses is independent of the network topology. It assumes constant failure rates for network components and uses a two-pass procedure in determining the effect of network reliability on the total system cost. A case study is presented to illustrate the importance of reliability considerations during the network design phase. Our analysis of the network reliability reveals that, in most cases, the incremental cost due to network failures will justify the additional units.
Prognostic Value of the Variability in Home-Measured Blood Pressure and Heart Rate: The Finn-Home Study

The objective of the study was to assess the prognostic value of variability in home-measured blood pressure (BP) and heart rate (HR) in a general population. We studied a representative sample of the Finnish adult population with 1866 study subjects aged 45-74 years. BP and HR self-measurements were performed on 7 consecutive days. The variabilities of BP and HR were defined as the SDs of morning minus evening, day-by-day, and first minus second measurements. The primary end point was incidence of a cardiovascular event. The secondary end point was total mortality. During a follow-up of 7.8 years, 179 subjects had experienced a cardiovascular event, and 130 subjects had died. In Cox proportional hazard models adjusted for age, sex, BP/HR, and other cardiovascular risk factors, morning-evening home BP variability (systolic/diastolic relative hazard: 1.04/1.10 [95% CI: 1.01-1.07/1.05-1.15] per 1-mm Hg increase in BP variability) and morning day-by-day home BP variability (relative hazard: 1.04/1.10 [95% CI: 1.00-1.07/1.04-1.16] per 1-mm Hg increase in BP variability) were predictive of cardiovascular events. Morning-evening home HR variability (relative hazard: 1.07 [95% CI: 1.02-1.12] per 1-bpm increase in HR variability) and morning day-by-day home HR variability (relative hazard: 1.11 [95% CI: 1.05-1.17] per 1-bpm increase in HR variability) were also independent predictors of cardiovascular events. Greater variabilities of morning home BP and HR are independent predictors of cardiovascular events. Because the variabilities of home BP and HR are easily acquired in conjunction with home BP and HR level, they should be used as the additive information in the assessment of cardiovascular risk.
Rank and regularity for averages over submanifolds

Abstract This paper establishes endpoint L p – L q and Sobolev mapping properties of Radon-like operators which satisfy a homogeneity condition (similar to semiquasihomogeneity) and a condition on the rank of a matrix related to rotational curvature. For highly degenerate operators, the rank condition is generically satisfied for algebraic reasons, similar to an observation of Greenleaf, Pramanik and Tang [A. Greenleaf, M. Pramanik, W. Tang, Oscillatory integral operators with homogeneous polynomial phases in several variables, J. Funct. Anal. 244 (2) (2007) 444–487] concerning oscillatory integral operators.
Mood disorders following traumatic brain injury

Mood disorders are a frequent complication of traumatic brain injury that exerts a deleterious effect on the recovery process and psychosocial outcome of brain injured patients. Prior psychiatric history and impaired social support have been consistently reported as risk factors for developing mood disorders after traumatic brain injury (TBI). In addition, biological factors such as the involvement of the prefrontal cortex and probably other limbic and paralimbic structures may play a significant role in the complex pathophysiology of these disorders. Preliminary studies have suggested that selective serotonin reuptake inhibitors such as sertraline, mood stabilizers such as sodium valproate, as well as stimulants and ECT may be useful in treating these disorders. Mood disorders occurring after TBI are clearly an area of neuropsychiatry in which further research in etiology as well as treatment is needed.
Testing the Information Set Perspective of UK Financial Reporting Standard No.3: Reporting Financial Performance

: This study investigates whether a broader range of financial performance measures as required by FRS No.3 (FRS3) provides incremental price information beyond a single earnings-based performance measure. I find that the additional performance components reported in the layered statement of performance and reconciliation of movements in shareholders' funds and alternative earnings per share that are voluntarily disclosed by UK firms are generally associated with share returns, and provide incremental price information beyond FRS3 all-inclusive earnings. This finding supports the information set perspective underlying FRS3, and has important implications for setting a global accounting standard on reporting financial performance.
Simulating visual attention

Selective visual attention serializes the processing of stimulus data to make efficient use of limited processing resources in the human visual system. This paper describes a connectionist network that exhibits a variety of attentional phenomena reported by Treisman, Wolford, Duncan, and others. As demonstrated in several simulations, a hierarchical, multiscale network that uses feature arrays with strong lateral inhibitory connections provides responses in agreement with a number of prominent behaviors associated with visual attention. The overall network design is consistent with a range of data reported in the psychological literature, and with neurophysiol-ogical characteristics of primate vision.
Reactive, dicationic electrophiles: electrophilic activation involving the phosphonium group

Abstract In the following letter, we report our studies of dicationic electrophiles involving the phosphonium group and we present evidence that the cationic phosphonium group may dramatically enhance the reactivities of adjacent electrophilic centers. We describe superacid-catalyzed reactions involving phosphonium-substituted aldehydes, ketones, olefins, and alkynes, and their conversions to products of condensation and addition reactions. We also report the direct observation of a phosphonium–carboxonium dication in FSO3H–SbF5–SO2ClF by low-temperature 13C NMR spectroscopy.
Mushy magma beneath Yellowstone

A recent prospective on the Yellowstone Caldera discounts its explosive potential based on inferences from tomographic studies which suggests a high degree of crystallization of the underlying magma body. In this study, we show that many of the first teleseismic P-wave arrivals observed at seismic stations on the edge of the caldera did not travel through the magma body but have taken longer but faster paths around the edge. After applying a number of waveform modeling tools, we obtain much lower seismic velocities than previous studies, 2.3 km/sec (V_p) and 1.1 km/sec (V_s). We estimate the physical state of the magma body by assuming a fluid-saturated porous material consisting of granite and a mixture of rhyolite melt and water and CO_2 at a temperature of 800°C and pressure at 5 km (0.1 GPa). We found that this relatively shallow magma body has a volume of over 4,300 km^3 and is about 32% melt saturated with about 8% water plus CO_2 by volume.
Nanoimprinted SU-8 Nanopillars and Hierarchically Branched Nanowires by Anodic Aluminum Oxide Templates and Their Optical Properties

We fabricated well-dispersed SU-8 nanopillars and hierarchically branched nanowires using nanoimprinted method. Anodic aluminum oxide (AAO) templates with branched pore structures were used as templates. We successfully fabricated high density, large aspect ratio, large area SU-8 patterns. It provides a convenient and powerful approach to produce complicated nanostructures on SU-8 photoresist. The optical reflectivity was measured to characterize the SU-8 surface. Unique optical properties could be observed from these SU-8 nanopillar structures.
Stability and robust regulation of battery driven boost converter with simple feedback

This paper investigates the problem of regulating the output voltage of a battery driven boost converter where the load is uncertain or changes within a certain range. By using the state-space averaging method, the open-loop system for regulating the output voltage is described as a 6th order differential equation with a bilinear term and input constraints. A simple saturated state feedback is designed by solving some optimization problem with linear matrix inequality constraints. The optimized controller is very close to an integrator feedback. Using the newly developed Lyapunov method, we analyze the stability and regulation of the closed-loop bilinear system. Computation shows that both the optimized state feedback and the integrator feedback can achieve practically global regulation in the presence of uncertain load and uncertain battery voltage. The results are validated by experimental systems.
A fast offset-free sample-and-hold circuit

A sample-and-hold stage is described that uses a CMOS cascode inverter and a novel switching scheme. Since the output voltage need not slew back to the V/sub os/ voltage level, the new circuit does not need to have an excessively high slew rate. The experimental results show that a high-speed and small-chip-area sample-and-hold circuit can be obtained when small-geometry (1- mu m design rule) devices are available. >
Analysis of combined conductive-radiative heat transfer in a two-dimensional rectangular enclosure with a gray medium

Combined conductive-radiative heat transfer in a two-dimensional enclosure is considered. The numerical procedure is based on a combination of two previous techniques that have been demonstrated to be successful for a two-dimensional pure radiation problem and a one-dimensional combined conductive-radiative heat transfer problem, respectively. Both temperature profile and heat transfer distributions are generated efficiently and accurately. Numerical data are presented to serve as benchmark solutions for two-dimensional combined conductive-radiative heat transfer. The accuracy of two commonly used approximation procedures for multidimensional combined conductive-radiative heat transfer is assessed. The additive solution, which is effective in generating approximation to one-dimensional combined conductive-radiative heat transfer, appears to be an acceptable empirical approach in estimating heat transfer in the present two-dimensional problem. The diffusion approximation, on the other hand, is shown to be generally inaccurate. For all optical thicknesses and conduction-radiation parameters considered (including the optically thick limit), the diffusion approximation is shown to yield significant errors in both the temperature and heat flux predictions.
Pressure and Perverse Flights to Familiarity

Under pressure, people often prefer what is familiar, which can seem safer than the unfamiliar. We show that such favoring of familiarity can lead to choices precisely contrary to the source of felt pressure, thus exacerbating, rather than mitigating, its negative consequences. In Experiment 1, time pressure increased participants’ frequency of choosing to complete a longer but incidentally familiar task option (as opposed to a shorter but unfamiliar alternative), resulting in increased felt stress during task completion. In Experiment 2, pressure to reach a performance benchmark in a chosen puzzle increased participants’ frequency of choosing an incidentally familiar puzzle that both augured and delivered objectively worse performance (i.e., fewer points obtained). Participants favored this familiar puzzle even though familiarity was established through unpleasant prior experience. This “devil you know” preference under pressure contrasted with disfavoring of the negatively familiar option in a pressure-...
Adaptive control of plants with unknown dead-zones

Model reference adaptive controllers are designed for plants with unknown dead-zones. Several control strategies are investigated in which two sets of adjustable parameters, one belonging to a dead-zone inverse and the other to a linear controller, are either kept fixed or adaptively updated. The developed adaptive control schemes ensure boundedness of all closed-loop signals and reduce the tracking error. >
Exact recovery of sparsely-used dictionaries

We consider the problem of learning sparsely used dictionaries with an arbitrary square dictionary and a random, sparse coefficient matrix. We prove that O(n log n) samples are sufficient to uniquely determine the coefficient matrix. Based on this proof, we design a polynomial-time algorithm, called Exact Recovery of Sparsely-Used Dictionaries (ERSpUD), and prove that it probably recovers the dictionary and coefficient matrix when the coefficient matrix is sufficiently sparse. Simulation results show that ER-SpUD reveals the true dictionary as well as the coefficients with probability higher than many state-of-the-art algorithms.
The synthesis and evaluation of temperature sensitive tubulin toxins.

Abstract The synthesis of several potent inhibitors of tubulin polymerization that exert their activities through interaction at the colchicine binding site is described. These agents were evaluated for their abilities to inhibit the polymerization of tubulin and the growth of neoplastic cell cultures. Additionally, the inhibition of tubulin polymerization activity of these agents was assessed over a temperature range of 30–45°C to ascertain the effect of temperature on this activity. Several of the compounds possess significant inhibition of tubulin polymerization activity, and select compounds exhibit this activity in a temperature dependent manner.
Nuclear Thermodynamics of the Heaviest Elements. II

The masses of the isotopes of the heaviest elements have been calculated from known decay data in the region, extended by means of decay energies calculated from closed decay-energy cycles and estimated from the systematics of alpha and beta decay energies. The absolute values of the masses are based on the mass-spectrometrically determined mass of Pb{sup 208} and a few measured neutron binding energies. The half-life systematics of alpha decay and spontaneous fission are also presented, and some predictions of the properties of as yet undiscovered nuclides are made.
The Returns to Computer Use Revisited: Have Pencils Changed the Wage Structure Too?

Are the large measured wage differentials for on-the-job computer use a true return to computer skills, or do they just reflect that higher wage workers use computers on their jobs? We examine this issue with three large cross-sectional surveys from Germany. First, we confirm that the estimated wage differential associated with computer use in Germany is very similar to the U.S. differential. Second, we also measure large differentials for on-the-job use of calculators, telephones, pens or pencils, or for those who work while sitting down. We argue that these findings cast some doubt on the literal interpretation of the computer use wage differential as reflecting true returns to computer use or skill.
Logic Databases on the Semantic Web: Challenges and Opportunities

An extended version of the abstract is available at {urhttp://www.SemanticWeb.org/ICLP2002}
Estimability and regulability of linear systems

A linear state-space system is said to be estimable if in estimating its state from its output the posterior error covariance matrix is strictly smaller than the prior covariance matrix. It is said to be regulatable if the quadratic cost of the state feedback control is strictly smaller than the cost when no feedback is used. Estimability and regulability are shown to be dual properties, equivalent to the nonreducibility of the Kalman filter and of the optimal linear quadratic regulator, respectively. >
3-bromo-2-pyrone: an easily prepared chameleon diene and a synthetic equivalent of 2-pyrone in thermal diels-alder cycloadditions

Abstract 3-Bromo-2-pyrone, a stable solid prepared by a new route (eq. 1), has been found to undergo smooth and regiospecific 2+4-cycloadditions between 78-90°C with both electron-rich and electron-deficient dienophiles; subsequent high-yield reductive debrominations produced halogen-free cycloadducts thus showing 3-bromo-2-pyrone to be a practical and effective synthetic equivalent of 2-pyrone in thermal Diels-Alder cycloadditions.
REAL COSTS OF NOMINAL GRADE INFLATION? NEW EVIDENCE FROM STUDENT COURSE EVALUATIONS

College GPAs in the United States rose substantially between the 1960’s and the 2000’s. Over the same period, study time declined by almost a half. This paper uses a 12-quarter panel of course evaluations from the University of California, San Diego to discern whether a link between grades and effort investment holds up in a micro setting. Results indicate that average study time would be about 50% lower in a class in which the average expected grade was an “A” than in the same course taught by the same instructor in which students expected a “C.” Simultaneity suggests estimates are biased toward zero. Findings do not appear to be driven primarily by the individual student’s expected grade, but by the average expected grade of others in the class. Class-specific characteristics that generate low expected grades appear to produce higher effort choices—evidence that nominal changes in grades may lead to real changes in effort investment.
Financing Strategies of New Technology-Based Firms: A Comparison of Women-and Men-Owned Firms

In this article we used data from the Kauffman Firm Survey to compare the financing strategies of women-and men-owned new technology-based firms. Our findings reveal that women raised dramatically less financial capital than men in the startup year and in the subsequent four years of operation. We also found that women used a significantly higher level of external debt and a significantly lower level of external equity during the startup year. Although our findings do not allow us to definitively rule out the possibility of discrimination, particularly in the market for external equity, our results indicate that women may have different motivations and expectations for their firms. These, in turn, may determine some of their financing choices.
Laser ranging and mapping with a photon-counting detector

We propose a new technique for remote sensing: photon-counting laser mapping. MicroChannel plate detectors with a crossed delay-line (MCP/CDL) readout combine high position accuracy and subnanosecond photon timing, at event rates of 10(6) detected photons per second and more. A mapping system would combine an MCP/CDL detector with a fast-pulse, high-repetition-rate laser illuminator. The system would map solid targets with exceptional in-range and cross-range resolution. The resulting images would be intrinsically three dimensional, without resorting to multiple viewing angles, so that objects of identical albedo could be discriminated. For a detector time resolution and pulse width of the order of 10(-10) s, the in-range resolution would be a few centimeters, permitting the discrimination of surfaces by their textures. Images could be taken at night, at illumination levels up to full moonlight, from ground, airborne, or space platforms. We discuss signal to noise as a function of laser flux and background level and present simulated images.
Elisabethamine: a new diterpene alkaloid from Pseudopterogorgia elisabethae

Detailed chemical studies of the methanolic extract of Pseudopterogorgia elisabethae, collected from the Florida Keys, have resulted in the isolation of elisabethamine (1), a new diterpene alkaloid. Its structure was established with the aid of extensive spectroscopic studies. Compound 1 exhibited cytotoxicity against lung and prostate cancer cell lines as determined by an MTT assay. # 2000 Elsevier Science Ltd. All rights reserved.
Transmission-line missile antennas

A class of protruding rocket antennas of low silhouette is analyzed in terms of an approximately equivalent circuit that consists of a shunt-driven transmission line terminated in a reactor at each end. Expressions for the currents in the several parts of the circuit are used to determine the Poynting vector and from this the radiation resistance referred to the current in the generator. The reactance is obtained from transmission-line formulas.
Price Spreads and Residential Housing Market Liquidity

Most studies of housing market liquidity have measured liquidity in terms of time on the market (TOM), and have sought to explain TOM in terms of property characteristics and measures of market conditions. This paper departs from past studies of housing market liquidity by examining the spread between the listing and contract prices.
Estimating the number of zero-one multi-way tables via sequential importance sampling

In 2005, Chen et al. introduced a sequential importance sampling (SIS) procedure to analyze zero-one two-way tables with given fixed marginal sums (row and column sums) via the conditional Poisson (CP) distribution. They showed that compared with Monte Carlo Markov chain (MCMC)-based approaches, their importance sampling method is more efficient in terms of running time and also provides an easy and accurate estimate of the total number of contingency tables with fixed marginal sums. In this paper, we extend their result to zero-one multi-way ( $$d$$ -way, $$d \ge 2$$ ) contingency tables under the no $$d$$ -way interaction model, i.e., with fixed $$d-1$$ marginal sums. Also, we show by simulations that the SIS procedure with CP distribution to estimate the number of zero-one three-way tables under the no three-way interaction model given marginal sums works very well even with some rejections. We also applied our method to Samson’s monks data set.
Improved Method for the Preparation of Oxadiazoles from Diacyl Hydrazines

N-methylimidazole (NMI) is used as the base in the triflic anhydride (Tf2O)–mediated formation of oxadiazoles from diacyl hydrazines. This reagent is superior to pyridine-derived bases in terms of cost and reaction profile.
Computer Analysis of Musical Allusions

Computer Music Journal, 27:1, pp. 11–28, Spring 2003 2003 Massachusetts Institute of Technology. In this article I describe a computer program called Sorcerer. Sorcerer provides analytical verification of the presence of musical allusions for what I call referential analysis, a semiotic approach roughly situated between hermeneutic (interpretive) analysis (e.g., Agawu 1991, 1996; Gjerdingen 1988; Nattiez 1990) and Retian (motivic) analysis (Reti 1962). Sorcerer associates patterns found in a target work— music under study—with several potential source works—music assumed to either influence or be influenced by the target work. Sorcerer then presents these patterns as possible references or allusions. The program lists its findings without regard for whether the composer of the target work consciously or subconsciously referenced the source work, only that the found allusions exist. I further describe the possible relevance and importance of this type of analysis as a complementary approach to more standard harmonic, melodic, and formal types of analysis, as a method for performers to better interpret the music they play, and as one possible approach to the deeper understanding of meaning in music.
NxTrim: optimized trimming of Illumina mate pair reads

Motivation Mate pair protocols add to the utility of paired-end sequencing by boosting the genomic distance spanned by each pair of reads, potentially allowing larger repeats to be bridged and resolved. The Illumina Nextera Mate Pair (NMP) protocol uses a circularization-based strategy that leaves behind 38-bp adapter sequences, which must be computationally removed from the data. While 'adapter trimming' is a well-studied area of bioinformatics, existing tools do not fully exploit the particular properties of NMP data and discard more data than is necessary. Results We present NxTrim, a tool that strives to discard as little sequence as possible from NMP reads. NxTrim makes full use of the sequence on both sides of the adapter site to build 'virtual libraries' of mate pairs, paired-end reads and single-ended reads. For bacterial data, we show that aggregating these datasets allows a single NMP library to yield an assembly whose quality compares favourably to that obtained from regular paired-end reads. Availability and implementation The source code is available at https://github.com/sequencing/NxTrim
Minor-minimal planar graphs of even branch-width

Let k ≥ 1 be an integer, and let H be a graph with no isolated vertices embedded in the projective plane, such that every homotopically non-trivial closed curve intersects H at least k times, and the deletion and contraction of any edge in this embedding results in an embedding that no longer has this property. Let G be the planar double cover of H obtained by lifting G into the universal covering space of the projective plane, the sphere. We prove that G is minor-minimal of branch-width 2k. We also exhibit examples of minor-minimal planar graphs of branch-width 6 that do not arise in this way.
Stereocontrolled 1,2-cis glycosylation as the driving force of progress in synthetic carbohydrate chemistry

Recent developments in stereoselective 1,2-cis glycosylation that have emerged during the past decade are surveyed herein. For detailed coverage of the previous achievements in the field the reader is referred to our earlier reviews: A. V. Demchenko, Curr. Org. Chem., 2003, 7, 35–79 and Synlett, 2003, 1225–1240.
Integrated magnetic full wave converter with flexible output inductor

A new integrated magnetic full wave DC/DC power converter that provides flexible transformer design by incorporating an independent output inductor winding is introduced. The transformer is implemented on a traditional three-leg magnetic core. The inductor winding can be separately designed to control the output current ripple. The cross-sectional area of the inductor core leg can be reduced dramatically. The operation and performance of the proposed circuit are verified on a 100 W prototype converter.
Rapid and Efficient Trifluoromethylation of Aromatic and Heteroaromatic Compounds Using Potassium Trifluoroacetate Enabled by a Flow System

The trifluoromethylation of aryl/heteroaryl iodides has been demonstrated using a flow system, enabling a rapid rate of reaction. A broad spectrum of trifluoromethylated compounds were prepared in good to excellent yields using CF3CO2K as the trifluoromethyl source.
Public Opinion and the Dynamics of Reform

Why do economic reforms that are proceeding successfully often run aground? In this paper we show that there might arise circumstances where the initial success of reform might result in it running into a political impasse. We suggest that the key might lie in the effect that the reform process has on the balance of political power. In particular, if initially successful reforms change the balance of political power in such a way as to make future redistribution less likely, then public opinion may turn against reform. Thus, in some sense, an initially successful reform may well end up sowing the seeds of its own destruction.
The Surface Compositon of Enceladus: Clues from the Ultraviolet

The reflectance of Saturn's moon Enceladus has been measured at far ultraviolet (FUV) wavelengths (115-190 nm) by Cassini's UltraViolet Imaging Spectrograph (UVIS). At visible and near infrared (VNIR) wavelengths Enceladus' reflectance spectrum is very bright, consistent with a surface composed primarily of H2O ice. At FUV wavelengths, however, Enceladus is surprisingly dark - darker than would be expected for pure water ice. We find that the low FUV reflectance of Enceladus can be explained by the presence of a small amount of NH3 and a small amount of a tholin in addition to H?O ice on the surface.
Illumination for computer generated pictures

The quality of computer generated images of three-dimensional scenes depends on the shading technique used to paint the objects on the cathode-ray tube screen. The shading algorithm itself depends in part on the method for modeling the object, which also determines the hidden surface algorithm. The various methods of object modeling, shading, and hidden surface removal are thus strongly interconnected. Several shading techniques corresponding to different methods of object modeling and the related hidden surface algorithms are presented here. Human visual perception and the fundamental laws of optics are considered in the development of a shading rule that provides better quality and increased realism in generated images.
Uncertainty analysis for estimates of the first indirect aerosol effect

Abstract. The IPCC has stressed the importance of producing unbiased estimates of the uncertainty in indirect aerosol forcing, in order to give policy makers as well as research managers an understanding of the most important aspects of climate change that require refinement. In this study, we use 3-D meteorological fields together with a radiative transfer model to examine the spatially-resolved uncertainty in estimates of the first indirect aerosol forcing. The global mean forcing calculated in the reference case is -1.30 Wm-2. Uncertainties in the indirect forcing associated with aerosol and aerosol precursor emissions, aerosol mass concentrations from different chemical transport models, aerosol size distributions, the cloud droplet parameterization, the representation of the in-cloud updraft velocity, the relationship between effective radius and volume mean radius, cloud liquid water content, cloud fraction, and the change in the cloud drop single scattering albedo due to the presence of black carbon are calculated. The aerosol burden calculated by chemical transport models and the cloud fraction are found to be the most important sources of uncertainty. Variations in these parameters cause an underestimation or overestimation of the indirect forcing compared to the base case by more than 0.6 Wm-2. Uncertainties associated with aerosol and aerosol precursor emissions, uncertainties in the representation of the aerosol size distribution (including the representation of the pre-industrial size distribution), and uncertainties in the representation of cloud droplet spectral dispersion effect cause uncertainties in the global mean forcing of 0.2~0.6 Wm-2. There are significant regional differences in the uncertainty associated with the first indirect forcing with the largest uncertainties in industrial regions (North America, Europe, East Asia) followed by those in the major biomass burning regions.
INCORPORATING RISK PREFERENCES INTO REAL OPTIONS MODELS

This paper develops a framework to link the expected utility analysis to real options models in order to capture the joint effects of risk aversion and irreversibility associated with real investments. It aims at modifying the theory of investment under uncertainty by incorporating decision makers' risk preferences and allows explicitly analyzing the impacts of risk aversion, uncertainty and irreversibility on decisions such as investment and resource allocations. It addresses the shortcomings of the commonly used expected utility and investment under uncertainty models be generalizing the theory of irreversible investment under uncertainty by allowing for risk-averse investors. We found that uncertainty, irreversibility and risk aversion are important determinants of the optimal timing of irreversible decisions. Ignoring risk preferences in real options models would lead to over or underestimation of magnitude of investments.
Modified Rayleigh conjecture method and its applications

Abstract The Rayleigh conjecture about convergence up to the boundary of the series representing the scattered field in the exterior of an obstacle D is widely used by engineers in applications. However this conjecture is false for some obstacles. AGR introduced the Modified Rayleigh Conjecture (MRC), which is an exact mathematical result. In this paper we present the theoretical basis for the MRC method for 2D and 3D obstacle scattering problems, for static problems, and for scattering by periodic structures. We also present successful numerical algorithms based on the MRC for various scattering problems. The MRC method is easy to implement for both simple and complex geometries. It is shown to be a viable alternative for other obstacle scattering methods. Various direct and inverse scattering problems require finding global minima of functions of several variables. The Stability Index Method (SIM) combines stochastic and deterministic method to accomplish such a minimization.
The Cauchy–Riemann equations on product domains

We establish the L 2 theory for the Cauchy–Riemann equations on product domains provided that the Cauchy–Riemann operator has closed range on each factor. We deduce regularity of the canonical solution on (p, 1)-forms in special Sobolev spaces represented as tensor products of Sobolev spaces on the factors of the product. This leads to regularity results for smooth data.
An unexpected allyl-transfer reaction under conditions of Lewis acid-promoted cyclization of homoallylic alcohols with aldehydes

The title reaction was observed along with cyclization in the SnCl4-promoted reaction of 2-[3,4,6-tri-O-benzyl-2-deoxy-2- (p-tolylsulfanyl)-β-D-glucopyranosyl]ethanal with pent-4-en-2-ol and this result was interpreted in terms of anchimeric assistance by sulfur to the unusual fragmentation of an intermediate alkoxycarbenium ion.
Motivated reasoning and verbal vs. numerical probability assessment: Evidence from an accounting context

Abstract A perplexing yet persistent empirical finding is that individuals assess probabilities in words and in numbers nearly equivalently, and theorists have called for future research to search for factors that cause differences. This study uses an accounting context in which individuals are commonly motivated to reach preferred (rather than accurate) conclusions. Within this context, I predict new differences between verbal and numerical probability assessments, as follows: first, individuals will justify an optimistic verbal assessment (e.g., somewhat possible) by retaining the option of re-defining it, in case of negative outcomes, as though the phrase really means something different, and, for that matter, means more things. This re-definition will maintain some connection to the original meaning of the phrase, but de-emphasized relative to the new meaning. Second, based on this behavior, I also predict individuals’ verbal probability assessments to be (1) more biased and yet (2) perceived as more justifiable than their numerical assessments. I find supportive evidence in an experiment designed to test the hypotheses. This study contributes to motivated reasoning and probability assessment theories (1) with new evidence of how individuals can word-smith in multiple attributes of a phrase to justify reaching a preferred conclusion, and (2) with new, reliable differences between verbal and numerical probability assessments. This study has important theoretical and practical implications relevant to organizational contexts in which people assess the likelihoods of uncertainties in words or numbers, and with motivations to reach a preferred conclusion.
Fetal imaging: Executive Summary of a Joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and magnetic resonance imaging in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost-effectiveness and to identify research opportunities. This article is the executive summary of the workshop.
Discrete time nonlinear filters with informative observations are stable

The nonlinear filter associated with the discrete time signal-observation model $(X_k,Y_k)$ is known to forget its initial condition as $k\to\infty$ regardless of the observation structure when the signal possesses sufficiently strong ergodic properties. Conversely, it stands to reason that if the observations are sufficiently informative, then the nonlinear filter should forget its initial condition regardless of any properties of the signal. We show that for observations of additive type $Y_k=h(X_k)+\xi_k$ with invertible observation function $h$ (under mild regularity assumptions on $h$ and on the distribution of the noise $\xi_k$), the filter is indeed stable in a weak sense without any assumptions at all on the signal process. If the signal satisfies a uniform continuity assumption, weak stability can be strengthened to stability in total variation.
Optoelectronics research for communication programs at the Goddard Space Flight Center

Current optoelectronics research and development of high-power, high-bandwidth laser transmitters, high-bandwidth, high-sensitivity optical receivers, pointing, acquisition and tracking components, and experimental and theoretical system modeling at the NASA Goddard Space Flight Center is reviewed. Program hardware and space flight milestones are presented. It is believed that these experiments will pave the way for intersatellite optical communications links for both the NASA Advanced Tracking and Data Relay Satellite System and commercial users in the 21st century. >
Input/Output Linearization Using Time Delay Control

A control procedure that uses Time Delay Control to achieve input/output linearization of a class of nonlinear systems is presented. The control system is characterized by a simple algorithm and enhanced robustness properties in comparison with current control algorithms. The paper first reviews the fundamentals of input/output linearization. The use of Time Delay Control is then shown to result in an exact linear system for sufficiently small delay time. Modified controllers for systems with a low-pass filter are also investigated. Simulation results show that the algorithm works well with measurement noise. The controller is also tested on a single-link flexible arm to show the effectiveness of the simple algorithm in the control of complicated systems.