cssi/SciSciGPT-SciSciNet huggingface dataset:
Challenges of NIH funding for young investigators: how the AGA is filling the gap via the AGA research foundation.

Thanks to cuts to federal funding for biomedical research, scientists entering the field face unprecedented challenges launching their careers. The AGA Governing Board is committed to supporting promising young investigators through the AGA Research Foundation. Today’s research lays the groundwork for tomorrow’s patient care. R esearch in digestive diseases in some ways has never offered more excitement and promise. The ideas and technological tools available to research have never been more enticing, and investigators are on the cusp of breakthroughs in many disease areas. However, these are also difficult times for researchers in gastroenterology, particularly young researchers, as resources to support the investigative mission have become somewhat scarcer largely because of the marked slowdown in government funding. In the late 1990s, the outlook had never been better, because Congress and the White House both agreed that the National Institutes of Health (NIH) was a national priority. Between 1998 and 2003, the NIH budget rose from $13 billion to more than $27 billion in a plan known as “the doubling.” In 2003, the Human Genome Project was completed, the United States was clearly #1 in the world in biomedical research, and researchers at most academic medical centers were poised for further successes.
RISK BASED EXPLANATIONS OF THE EQUITY PREMIUM

Abstract This essay reviews the family of models that seek to provide aggregate risk-based explanations for the empirically observed equity premium. Theories based on non-expected utility preference structures, limited financial market participation, model uncertainty, and the small probability of enormous losses are detailed. We impose the additional requirements that candidate models yield consistent intertemporal portfolio choice and that a representative agent can be constructed that is independent of the underlying heterogeneous economy's initial wealth distribution. While many models are able to replicate a wide variety of financial statistics including the premium, few satisfy these latter criteria as well.
Measuring the Unequal Gains from Trade

Individuals that consume dierent baskets of goods are dierentially aected by relative price changes caused by international trade. We develop a methodology to measure the unequal gains from trade across consumers within countries that is applicable across countries and time. The approach uses data on aggregate expenditures across goods with dierent income elasticities and parameters estimated from a non-homothetic gravity equation. We nd considerable variation in the pro-poor bias of trade depending on the income elasticity of each country’s exports. Nonhomotheticities across sectors imply that the gains from trade typically favor the poor, who concentrate spending in more traded sectors.
Age–Period–Cohort Analysis

When evaluating temporal trends, three perspectives to be considered are age, period and cohort. Age refers to chronological age of a subject when the outcome of interest occurs, and period the corresponding calendar date. Cohort refers to the year of birth, which identifies a generation, but this may be calculated by taking the difference between age and period, which can make these analyses difficult to interpret. Approaches for analyzing these temporal perspectives are described, including approaches to the identifiability problem that arises when one attempts to fit models that include all three temporal parameters at the same time. These methods are demonstrated using data on births per 1000 women among US blacks. Keywords: age-period-cohort models; identifiability; birth rates
Seasonal Migration and Early Childhood Development

This paper provides unique evidence of the positive consequences of seasonal migration for investments in early childhood development. The authors analyze migration in a poor shock-prone border region in rural Nicaragua where it offers one of the main household income diversification and risk coping strategies. IV estimates show, somewhat surprisingly, that in particular mother's migration has a positive effect on early cognitive development. The authors attribute these findings to changes in income and to the intra-household empowerment gains resulting from mother's migration, which offset potential negative ECD effects from temporary lack of parenting. This paper, hence, illustrates how increased opportunities in seasonal migration due to higher South-South mobility might positively affect early childhood development and as such long-term poverty reduction.
α-Ketocarboxylic acid-based inhibitors of protein tyrosine phosphatases

A series of aryl alpha-ketocarboxylic acids was synthesized and investigated as inhibitors for the protein tyrosine phosphatase from Yersinia enterocolitica. IC(50) values for these compounds range from 79 to 2700 microM. Larger aromatic groups, and aromatic groups with high electron density, lead to more potent inhibitors. In general, the related aryl alpha-hydroxycarboxylic acids show lower activity.
Binary Hermitian forms over a cyclotomic field

Abstract Let ζ be a primitive fifth root of unity and let F be the cyclotomic field F = Q ( ζ ) . Let O ⊂ F be the ring of integers. We compute the Voronoi polyhedron of binary Hermitian forms over F and classify GL 2 ( O ) -conjugacy classes of perfect forms. The combinatorial data of this polyhedron can be used to compute the cohomology of the arithmetic group GL 2 ( O ) and Hecke eigenforms.
Realizing the gains from trade: Export crops, marketing costs, and poverty

This paper explores the role of export costs in the process of poverty reduction in rural Africa. The authors claim that the marketing costs that emerge when the commercialization of export crops requires intermediaries can lead to lower participation into export cropping and, thus, to higher poverty. They test the model using data from the Uganda National Household Survey. The findings show that: i) farmers living in villages with fewer outlets for sales of agricultural exports are likely to be poorer than farmers residing in marketendowed villages; ii) market availability leads to increased household participation in export cropping (coffee, tea, cotton, fruits); and iii) households engaged in export cropping are less likely to be poor than subsistence-based households. The authors conclude that the availability of markets for agricultural export crops helps realize the gains from trade. This result uncovers the role of complementary factors that provide market access and reduce marketing costs as key building blocks in the link between the gains from export opportunities and the poor.
Automating software design

To anyone who has had the slightest connection with the design and construction of large programs for digital computers, it is obvious that this is no trivial task. Many times the design of such programs is woefully inadequate, and the effort required to get them right is tremendous. The sometimes ruinous cost of such inadequate design is well-known.
The life-course perspective and social policies : an issues note

A number of trends are changing the nature of social risks and increase the importance of human capital, adaptability and flexibility. This paper discusses the usefulness of a life-course perspective in developing proactive social policies that better fit the changing life cycles of individuals who combine formal work with other activities on transitional labor markets. It pays special attention to the accumulation and maintenance of human capital over the life course and stresses that reconciliation of work and family goes beyond child-care facilities and parental leave, and involves the entire life course. In particular, longer and deeper involvement in paid employment allows people to exploit their longer life to reconcile the two ambitions of, first, investing in the next generation as a parent and, second, pursuing a fulfilling career in paid work in which one keeps learning. Greater flexibility of working time over the life course requires more individual responsibility for financing leave. Moreover, rather than shielding older insiders through employment protection, labor-market institutions should enable parents of young children to easily enter and remain in the labor market. Finally, more activating social assistance and in-work benefits should replace the passive income support for breadwinners that results in high minimum-wage floors.
Remote preparation of quantum states

Remote state preparation is the variant of quantum state teleportation in which the sender knows the quantum state to be communicated. The original paper introducing teleportation established minimal requirements for classical communication and entanglement but the corresponding limits for remote state preparation have remained unknown until now: previous work has shown, however, that it not only requires less classical communication but also gives rise to a tradeoff between these two resources in the appropriate setting. We discuss this problem from first principles, including the various choices one may follow in the definitions of the actual resources. Our main result is a general method of remote state preparation for arbitrary states of many qubits, at a cost of 1 bit of classical communication and 1 bit of entanglement per qubit sent. In this "universal" formulation, these ebit and cbit requirements are shown to be simultaneously optimal by exhibiting a dichotomy. Our protocol then yields the exact tradeoff curve for memoryless sources of pure states (including the case of incomplete knowledge of the ensemble probabilities), based on the recently established quantum-classical tradeoff for visible quantum data compression. A variation of that method allows us to solve the even more general problem of preparing entangled states between sender and receiver (i.e., purifications of mixed state ensembles). The paper includes an extensive discussion of our results, including the impact of the choice of model on the resources, the topic of obliviousness, and an application to private quantum channels and quantum data hiding.
International transmission of anticipated inflation under alternative exchange-rate regimes

Abstract This paper studies the international transmission of anticipated inflation. A two-country, two-good, two-currency, cash-in-advance model is used to examine analytically and numerically the consequences of changes in a country's inflation rate. Domestic monetary policy influences real activity at home through an inflation-tax channel. These real effects are transmitted to the foreign country via fluctuations in the real exchange rate. Under a flexible nominal exchange rate, inflation is a beggar-thy-neighbor policy. Under a fixed nominal exchange rate, each country suffers a welfare loss when one country inflates. The quantitative results are fairly insensitive to variations in the cash–credit mix used to finance investment expenditures.
VERTICAL ATMOSPHERIC STRUCTURE IN A VARIABLE BROWN DWARF: PRESSURE-DEPENDENT PHASE SHIFTS IN SIMULTANEOUS HUBBLE SPACE TELESCOPE-SPITZER LIGHT CURVES

Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889 431026 over the wavelength ranges 1.1 1.7 µm and broadband 4.5 µm. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the atmospheric structure with clouds in brown dwarfs and extrasolar planets. Subject headings: brown dwarfs — stars: atmospheres — stars: individual (2MASSJ22282889 4310262) — stars: variables: general
Exponentially Stable Nonlinear Systems Have Polynomial Lyapunov Functions on Bounded Regions

This paper presents a proof that existence of a polynomial Lyapunov function is necessary and sufficient for exponential stability of a sufficiently smooth nonlinear vector field on a bounded set. The main result states that if there exists an n -times continuously differentiable Lyapunov function which proves exponential stability on a bounded subset of Rn, then there exists a polynomial Lyapunov function which proves exponential stability on the same region. Such a continuous Lyapunov function will exist if, for example, the vector field is at least n-times continuously differentiable. The proof is based on a generalization of the Weierstrass approximation theorem to differentiable functions in several variables. Specifically, polynomials can be used to approximate a differentiable function, using the Sobolev norm W 1,infin to any desired accuracy. This approximation result is combined with the second-order Taylor series expansion to show that polynomial Lyapunov functions can approximate continuous Lyapunov functions arbitrarily well on bounded sets. The investigation is motivated by the use of polynomial optimization algorithms to construct polynomial Lyapunov functions.
Limit Sets as Examples in Noncommutative Geometry

The fundamental group of a hyperbolic manifold acts on the limit set, giving rise to a cross-product C ∗ -algebra. We construct nontrivial K-cycles for the cross-product algebra, thereby extending some results of Connes and Sullivan to higher dimensions. We also show how the Patterson-Sullivan measure on the limit set can be interpreted as a center-valued KMS state.
A digital self excited loop for accelerating cavity field control

We have developed a digital process that emulates an analog oscillator and ultimately a self excited loop (SEL) for field control. The SEL, in its analog form, has been used for many years for accelerating cavity field control. In essence the SEL uses the cavity as a resonant circuit - much like a resonant (tank) circuit is used to build an oscillator. An oscillating resonant circuit can be forced to oscillate at different, but close, frequencies to resonance by applying a phase shift in the feedback path. This allows the circuit to be phased-locked to a master reference, which is crucial for multiple cavity accelerators. For phase and amplitude control the SEL must be forced to the master reference frequency, and feedback provided for in both dimensions. The novelty of this design is in the way digital signal processing (DSP) is structured to emulate an analog system. While the digital signal processing elements are not new, to our knowledge this is the first time that the digital SEL concept has been designed and demonstrated. This paper reports on the progress of the design and implementation of the digital SEL for field control of superconducting accelerating cavities.
Noninvasive Sphenopalatine Ganglion Block for Acute Headache in the Emergency Department: A Randomized Placebo-Controlled Trial

Study objective We seek to test the efficacy of noninvasive sphenopalatine ganglion block for the treatment of acute anterior headache in the emergency department (ED) using a novel noninvasive delivery device. Methods We conducted a randomized, double-blind, placebo-controlled trial evaluating bupivacaine anesthesia of the sphenopalatine ganglion for acute anterior or global-based headache. This study was completed in 2 large academic EDs. Bupivacaine or normal saline solution was delivered intranasally (0.3 mL per side) with the Tx360 device. Pain and nausea were measured at 0, 5, and 15 minutes by a 100-mm visual analog scale. The primary endpoint was a 50% reduction in pain at 15 minutes. Telephone follow-up assessed 24-hour pain and nausea through a 0- to 10-point verbal scale and adverse effects. Results The median reported baseline pain in the bupivacaine group was 80 mm (IQR 66 mm - 93 mm) and 78.5 mm (IQR 64 mm to 91.75 mm) in the normal saline solution group. A 50% reduction in pain was achieved in 48.8% of the bupivacaine group (20/41 patients) versus 41.3% in the normal saline solution group (19/46 patients), for an absolute risk difference of 7.5% (95% confidence interval [CI] –13% to 27.1%). As a secondary outcome, at 24 hours, more patients in the bupivacaine group were headache free (24.7% difference; 95% CI 2.6% to 43.6%) and more were nausea free (16.9% difference; 95% CI 0.8% to 32.5%). Conclusion For patients with acute anterior headache, sphenopalatine ganglion block with the Tx360 device with bupivacaine did not result in a significant increase in the proportion of patients achieving a greater than or equal to 50% reduction in headache severity at 15 minutes compared with saline solution applied in the same manner.
Reaction of Cyanogen with SiO2 Surfaces

Infrared spectra (4000 to 1300 cm−1) of SiO2 specimens with high surface areas which had been exposed to (CN)2 at 25° to 600°C were recorded. Sorption was slight at 25°, but extensive reaction occurred at higher temperatures. The main effects of the sorption were the decrease of the 3747 cm−1 band of surface Si-OH groups and the buildup of a prominent band at 2310 cm−1 thought to be caused by surface Si-NCO species rather than Si-OCN species. The data suggest that, in addition to the isocyanate formed in the dehydroxylation reaction, HCN produced in that reaction led to the formation of Si-CN and Si-OH
Strichartz Estimates on Schwarzschild Black Hole Backgrounds

We study dispersive properties for the wave equation in the Schwarzschild space-time. The first result we obtain is a local energy estimate. This is then used, following the spirit of [29], to establish global-in-time Strichartz estimates. A considerable part of the paper is devoted to a precise analysis of solutions near the trapping region, namely the photon sphere.
Appointments of outsiders to Japanese boards: Determinants and implications for managers

Abstract This paper investigates the determinants of appointments of outsiders — directors previously employed by banks (bank directors) or by other nonfinancial firms (corporate directors) — to the boards of large nonfinancial Japanese corporations. Such appointments increase with poor stock performance; those of bank directors also increase with earnings losses. Turnover of incumbent top executives increases substantially in the year of both types of outside appointments. We perform a similar analysis for outside appointments in large U.S. firms and find different patterns. We conclude that banks and corporate shareholders play an important monitoring and disciplinary role in Japan.
Synthesis of averaged circuit models for switched power converters

An approach for synthesizing averaged circuit models for switching converters that realize their respective state-space averaged models is presented. The method proceeds in a systematic fashion by determining appropriate averaged circuit elements that are consistent with the averaged circuit waveforms. The averaged circuit models that are obtained are syntheses of the state-space averaged models for the underlying switched circuits. An important feature of the method is that it is applicable to switched circuits whose non-switch elements may be nonlinear. This approach is compared and contrasted with the results on averaged circuit models available in the literature. >
Degradation of Silicon Carbide by Molten Lithium

The mechanical behavior of silicon carbide exposed to molten lithium was evaluated at exposure temperatures from 200° to 1000°C. For temperatures up to 600°C, there was little change in strength and the fracture was controlled by preexisting surface flaws on the specimen surface or edges. Above 600°C, two strength populations developed: a relatively high-strength group characterized by transgranular fracture and a low-strength group characterized by intergranular degradation. Quantitative chemical analysis was used to explain the lithiuminduced strength degradation. This information, coupled with the fractographic analysis, led to a description of the corrosion mechanism.
On the very concept of free will

Determinism seems to rule out a robust sense of options but also prevent our choices from being a matter of luck. In this way, free will seems to require both the truth and falsity of determinism. If the concept of free will is coherent, something must have gone wrong. I offer a diagnosis on which this puzzle is due at least in part to a tension already present in the very idea of free will. I provide various lines of support for this hypothesis, including some experimental data gathered by probing the judgments of non-specialists.
A dataflow approach to efficient change detection of HTML/XML documents in WebVigiL

The burgeoning data on the Web makes it difficult for one to keep track of the changes that constantly occur to specific information of interest. Currently, the most widespread way of detecting changes occurring to Web content is to periodically retrieve the pages of interest and check them for changes. This approach puts the burden on the user and wastes time and resources. Alternatively, systems that detect any change to a page is an overkill as it presents information that may not be relevant. Timeliness of change detection is also an issue in this approach. In this paper, we present a change-monitoring system--WebVigiL--which efficiently monitors user-specified Web pages for customized changes and notifies the user in a timely manner. The focus of this paper is on the dataflow approach used for detecting multiple types of changes to a page and to monitor changes to more then one page at a time. This approach has been optimized to group similar/same specifications to reduce the computation of changes. Multiple changes to the same page as well as to different pages are handled in our approach. As a special case, this includes the monitoring of Web pages containing frames. We also provide the overall architecture and functionality of the WebVigiL system to highlight the role of change detection graph (CDG) which forms the core of the system.
Market Maker Quotation Behavior and Pretrade Transparency

We examine the impact of differing levels of pretrade transparency on the quotation behavior of Nasdaq market makers. We find that market makers are more likely to quote on odd ticks, and to actively narrow the spread, when they can do so anonymously by posting limit orders on Electronic Communication Networks (ECNs). From a public policy perspective, our findings suggest that making the level of pretrade transparency on Nasdaq more opaque by allowing anonymous quotes could improve price competition and narrow spreads further.
Advanced thermal tester for accurate measurement of internal thermal resistance of high power electronic modules

A thermal tester has been developed for the accurate measurement of the internal thermal resistance of high-power electronic modules. The tester is designed for the simultaneous measurement of 20 electronic modules each dissipating in excess of 200 W. The heat dissipated is transmitted to the ambient by water-cooled cold plates dedicated to each test site. The tester system layout, mounting assembly, hydraulic design, cold-plate spreader design and data acquisition instrumentation are described. Sample measurements and the associated uncertainty are also discussed. The sample results are validated by comparison with thermal modeling.
An Improved Synthesis of BrettPhos‐ and RockPhos‐Type Biarylphosphine Ligands

Improved processes for the preparation of biphenyl-based phosphine ligands t-BuBrettPhos, RockPhos, and BrettPhos are presented. The new methods, featuring the use of Grignard reagents and catalytic amounts of copper, are superior to the previous methods, which require the use of t-butyllithium and stoichiometric amounts of copper. Specifically, the use of less dangerous reagents provides a safer process, while the use of catalytic amounts of copper allows for the isolation of pure products in high yield. These improvements are particularly significant for the large scale preparation of these ligands.
Timescales of fluvial activity and intermittency in Milna Crater, Mars

Milna Crater, Mars (23.4S, 12.3W) exhibits signs of fluvial modification early in Mars history, including a large multi-lobed fan deposit cut by several sinuous valleys. We describe the past hydrologic conditions in Milna and the surrounding area, including a potential lake with a volume of 50 km^3. We also introduce new methods (i) to calculate the timescale of sediment deposition by considering fluvial sediment input into the entire crater while accounting for non-fluvial input, and (ii) to place improved constraints on the channel dimensions through which sediment was delivered to Milna by comparing to the dimensions of inner channels found in valleys in the region surrounding Milna. By calculating the flux of fluid and sediment into the crater, we find that the crater cavity was flooded for at least months and that the time of active fluvial sediment transport without hiatus is on the order of decades to centuries, with a preferred timescale of centuries. We also calculate the total amount of water required to transport the volume of sediment we measure in Milna and conclude that impacts alone are likely insufficient to deliver enough water to Milna to allow the sedimentary fill we see. Combining the timescales of fluvial activity in the adjacent Parana Valles with estimates for global Noachian erosion rates, we calculate an intermittency factor for fluvial activity of ∼0.01–0.1% during 10^5–10^6 yr near the Noachian–Hesperian boundary in the Parana Valles region. These values are comparable to arid climates on Earth where the majority of fluvial sedimentary transport takes place during floods with multi-year to decadal recurrence intervals. Our calculations of intermittency help to quantitatively reconcile the divergent estimates of the short and long timescales of fluvial activity on Mars reported in the literature.
Mean-Field Conditions for Percolation on Finite Graphs

Let {Gn} be a sequence of finite transitive graphs with vertex degree d = d(n) and |Gn| = n. Denote by pt(v, v) the return probability after t steps of the non-backtracking random walk on Gn. We show that if pt(v, v) has quasi-random properties, then critical bond-percolation on Gn behaves as it would on a random graph. More precisely, if $$\mathop {\rm {lim\, sup\,}} \limits_{n} n^{1/3} \sum\limits_{t = 1}^{n^{1/3}} {t{\bf p}^t(v,v) < \infty ,}$$ then the size of the largest component in p-bond-percolation with \({p =\frac{1+O(n^{-1/3})}{d-1}}\) is roughly n2/3. In Physics jargon, this condition implies that there exists a scaling window with a mean-field width of n−1/3 around the critical probability \({p_c =\frac{1}{d-1}}\).
Multiagent reinforcement learning algorithm using temporal difference error

When agent chooses some action and does state transition in present state in reinforcement learning, it is important subject to decide how will reward for conduct that agent chooses. In this paper, by new meta heuristic method to solve hard combinatorial optimization problems, we introduce Ant-Q learning method that has been proposed to solve Traveling Salesman Problem (TSP) to approach that is based for population that use positive feedback as well as greedy search, and suggest ant reinforcement learning model using TD-error(ARLM-TDE). We could know through an experiment that proposed reinforcement learning method converges faster to optimal solution than original ACS and Ant-Q.
A hybrid approach to recognizing programming plans

Most current models of program understanding are unlikely to scale up successfully. Top-down approaches require advance knowledge of what the program is supposed to do, which is rarely available with aging software systems. Bottom-up approaches require complete matching of the program against a library of programming plans, which is impractical with the large plan libraries needed to understand programs that contain many domain-specific plans. This paper presents a hybrid approach to program understanding that uses an indexed, hierarchical organization of the plan library to limit the number of candidate plans considered during program understanding. This approach is based on observations made from studying student programmers attempt to perform bottom-up understanding on geometrically-oriented C functions. >
Five-coloring graphs on the Klein bottle

We exhibit an explicit list of nine graphs such that a graph drawn in the Klein bottle is 5-colorable if and only if it has no subgraph isomorphic to a member of the list.
Homeostatic control for a mobile robot: Dynamic replanning in hazardous environments

A longstanding goal of robotics has been to introduce intelligent machines into environments dangerous to humans. These environments also pose hazards to the robots themselves. By embedding sensing devices as a means for monitoring the internal state of the robot, dynamic plan reformulation can occur in situations that threaten the existence of the robot. A method exploiting an analogy to the endocrine control system is forwarded as the preferred method for homeostatic control—the maintenance of a safe internal environment for the machine. Examples are given describing the impact of fuel reserve depletion and global temperature stress. A methodology using signal schemas as a means to supplement the existing motor schema control found in the Autonomous Robot Architecture (AuRA) is presented.
Noncontiguous I/O through PVFS

With the tremendous advances in processor and memory technology, I/O has risen to become the bottleneck in high-performance computing for many applications. The development of parallel file systems has helped to ease the performance gap, but I/O still remains an area needing significant performance improvement. Research has found that noncontiguous I/O access patterns in scientific applications combined with current file system methods, to perform these accesses lead to unacceptable performance for large data sets. To enhance performance of noncontiguous I/O, we have created list I/O, a native version of noncontiguous I/O. We have used the Parallel Virtual File System (PVFS) to implement our ideas. Our research and experimentation shows that list I/O outperforms current noncontiguous I/O access methods in most I/O situations and can substantially enhance the performance of real-world scientific applications.
Constraining Dark Matter Halo Profiles and Galaxy Formation Models Using Spiral Arm Morphology. I. Method Outline

We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well correlated with the rate of
A Short Synthesis of a Novel Ring-Expanded Purine and Its Nucleoside Analogue Containing the Imidazo[4,5-e][1,3]diazepine Ring Skeleton with Multiple Amino Substituents Attached to the 7-Membered Ring

Abstract The synthesis of 4,6,8-triaminoimidazo[4,5-e][1,3]diazepine (1) and its nacleoside analogue (6) are reported. The heterocycle was prepared in a single step by condensation of 4,5-dicyanoimidazole with guanidine. The 5,7-fused ring structure of 1 was distinguished from the other possible 5:5-fused isomer 2 by preparing the 15N-labeled heterocycle (1∗) and exploring its 15N-1H coupling patterns in both 1H and 15N NMR spectra. These spectral patterns also enabled establishment of the triamino tautomeric form of 1 as assigned. Compound 1, a novel ring-expanded (“fat”) analogue of purine, is anticipated to be planar and aromatic as predicted by molecular modeling. The 1 -benzyl analogue (4), a protocol for the ribosyl analogue 6, was similarly prepared from 1-benzyl-4,5-dicyanoimidazole. The nucleoside 6 was prepared by the modified Vorbrulggen ribosylation of 1. The position of ribosylation was unequivocally established by an unambiguous synthesis of 6 from condensation of 1 -(2′,3′,5-tri-O-benzoyl-β...
Reversible projective measurement in quantum ensembles

We present experimental NMR demonstration of a scheme of reversible projective measurement, which allows extracting information on outcomes and probabilities of a projective measurement in a non-destructive way, with a minimal net effect on the quantum state of an ensemble. The scheme uses reversible dynamics and weak measurement of the intermediate state. The experimental system is an ensemble of 133Cs (S = 7/2) nuclei in a liquid-crystalline matrix.
Programmable canonical correlation analysis: a flexible framework for blind adaptive spatial filtering

We present a new framework known as the programmable canonical correlation analysis (PCCA) for the design of blind adaptive spatial filtering algorithms that attempt to separate one or more signals of interest from unknown cochannel interference and noise. Unlike many alternatives, PCCA does not require knowledge of the calibration data for the array, directions of arrival, training signals, or spatial autocorrelation matrices of the noise or interferers. A novel aspect of PCCA is the ease with which new algorithms, targeted at capturing all signals from particular classes of interest, can be developed within this framework. Several existing algorithms are unified within the PCCA framework, and new algorithms are derived as examples. Analysis for the infinite-collect case and simulation for the finite-collect case illustrate the operation of specific algorithms within the PCCA framework.
Could Some Black Holes Have Evolved from Wormholes

One way to explain the present acceleration of the universe is Einstein's cosmological constant. It is quite likely, in view of some recent studies, that a time-dependent equation of state had caused the Universe to evolve from an earlier phantom-energy model. In that case, traversable wormholes could have formed spontaneously. It is shown in this paper that such wormholes would eventually have become black holes. This would provide a possible explanation for the huge number of black holes discovered, while any evidence for the existence of wormholes is entirely missing, even though wormholes are just as good, in terms of being a prediction of general relativity, as black holes.
Sliced inverse moment regression using weighted chi-squared tests for dimension reduction

We propose a new method for dimension reduction in regression using the first two inverse moments. We develop corresponding weighted chi-squared tests for the dimension of the regression. The proposed method considers linear combinations of sliced inverse regression (SIR) and the method using a new candidate matrix which is designed to recover the entire inverse second moment subspace. The optimal combination may be selected based on the p-values derived from the dimension tests. Theoretically, the proposed method, as well as sliced average variance estimate (SAVE), is more capable of recovering the complete central dimension reduction subspace than SIR and principle Hessian directions (pHd). Therefore it can substitute for SIR, pHd, SAVE, or any linear combination of them at a theoretical level. Simulation study indicates that the proposed method may have consistently greater power than SIR, pHd, and SAVE.
Stability theory for countably infinite systems of differential equations

New stability results for a class of countably infinite systems of differential equations are established. We consider those systems which may be viewed as an interconnection of countably infinitely many free or isolated subsystems. Throughout, the analysis is accomplished in terms of simpler subsystems and in terms of the system interconnecting structure. This approach makes it often possible to circumvent difficulties usually encountered in the application of the Lyapunov approach to complex systems with intricate structure. Both scalar Lyapunov functions and vector Lyapunov functions are used in the analysis. The applicability of the present results is demonstrated by means of several motivating examples, including a neural model.
Efficiently inducing features of conditional random fields

Conditional Random Fields (CRFs) are undirected graphical models, a special case of which correspond to conditionally-trained finite state machines. A key advantage of CRFs is their great flexibility to include a wide variety of arbitrary, non-independent features of the input. Faced with this freedom, however, an important question remains: what features should be used? This paper presents an efficient feature induction method for CRFs. The method is founded on the principle of iteratively constructing feature conjunctions that would significantly increase conditional log-likelihood if added to the model. Automated feature induction enables not only improved accuracy and dramatic reduction in parameter count, but also the use of larger cliques, and more freedom to liberally hypothesize atomic input variables that may be relevant to a task. The method applies to linear-chain CRFs, as well as to more arbitrary CRF structures, such as Relational Markov Networks, where it corresponds to learning clique templates, and can also be understood as supervised structure learning. Experimental results on named entity extraction and noun phrase segmentation tasks are presented.
The Spatial Distribution of Entrepreneurial Support Networks: Evidence from Semiconductor Initial Public Offerings from 1996 through 2000

The Spatial Distribution of Entrepreneurial Support Networks: Evidence from Semiconductor Initial Public Offerings from 1996 through 2000* Working Paper 153 March 1, 2003 ©Copyright 2003 by BRIE Donald Patton Senior Research Associate Department of Human and Community Development University of California, Davis Davis, CA 95616 Martin Kenney Department of Human and Community Development University of California, Davis Davis, CA 95616 (530) 752–0328 (Office) (530) 752–5660 (Fax) mfkenney@ucdavis.edu and Berkeley Roundtable on the International Economy UC, Berkeley * The authors thank the University of California Office of the President ’ Industry-University s Cooperative Research Program, the University of California, Davis Academic Senate, and the Alfred P. Sloan Foundation for providing funding for this research project.
Polynomial methods for structure from motion

The authors analyze the limitations of structure from motion (SFM) methods presented in the literature and propose the use of a polynomial system of equations, with the unit quaternions representing rotation, to recover SFM under perspective projection. The authors combine the equations by the method of resultants with the MAXIMA symbolic algebra system, reducing the system to a single polynomial. Its real roots are then found with Sturm sequences. Since this system has multiple solutions, a hypothesize-and-verify scheme is used to eliminate incorrect ones. The scheme diminishes the sensitivity of using polynomial equations. The authors examine the effect of different rotation axes and angles on SFM accuracy and compare the performance of the algorithm to a few earlier approaches. Generally, it is found that a large amount of motion is the most important factor in getting good SFM accuracy. >
Acquiring Receptive Morphology: A Connectionist Model

This paper describes a modular connectionist model of the acquisition of receptive inflectional morphology. The model takes inputs in the form of phones one at a time and outputs the associated roots and inflections. Simulations using artificial language stimuli demonstrate the capacity of the model to learn suffixation, prefixation, infixation, circumfixation, mutation, template, and deletion rules. Separate network modules responsible for syllables enable to the network to learn simple reduplication rules as well. The model also embodies constraints against association-line crossing.
Linearized gravity in the Karch–Randall braneworld

Abstract We present a linearized gravity investigation of the bent braneworld, where an AdS 4 brane is embedded in AdS 5 . While we focus on static spherically symmetric mass distributions on the brane, much of the analysis continues to hold for more general configurations. In addition to the identification of the massive Karch–Randall graviton and a tower of Kaluza–Klein gravitons, we find a radion mode that couples to the trace of the energy–momentum tensor on the brane. The Karch–Randall radion arises as a property of the embedding of the brane in the bulk space, even in the context of a single brane model.
Max Weber's mysticism

For much of his life Weber favored the rational activity of the ascetic in contrast to the irrational passivity of the mystic. However, Weber developed a growing interest in mysticism both in the East and the West. Johannes Tauler and his teacher Meister Eckhart offered Weber glimpses of the western mystic's beliefs. Perhaps in Weber's last years, religion and mysticism moved from being merely intellectual interests to something more significant and personal.
Comparison of outcomes between 20, 23 and 25 gauge vitrectomy for idiopathic macular hole

To compare the results of 20, 23, 25 gauge pars plana vitrectomy (PPV) with two different gas tamponades for idiopathic macular hole (MH) in a multi-surgeon vitroretinal practice. In this comparative, retrospective, interventional case series, the medical charts of 142 eyes/130 patients were reviewed. Patients who matched our inclusion criteria: eye with stage 2, 3, or 4 MH that underwent 20, 23, or 25 gauge PPV, internal limiting membrane (ILM) peeling, and fluid-gas exchange from January, 2005 to May, 2012 and had at least 6 months follow-up. The best current corrected visual acuity (VA) and anatomical status of the MH were assessed by optical coherent tomography (OCT) at 6 months, 1 year, and 2 years after vitrectomy. The MH closed successfully after primary vitrectomy in 86.5 % (20 gauge), 96.4 % (23 gauge), and 92 % (25 gauge). Preoperative VA median were 20\126 (20 gauge), 20\100 (23 gauge), and 20\80 (25 gauge). At 6 months and 2 years postoperative VA did not differ significantly between the 3 groups (p = 0.570, and 0.054 respectively). However, at 12 months postoperative VA median 20\60 (20 gauge), 20\69 (23 gauge), and 20\40 (25 gauge) differ significantly (p = 0.005) likely due to cataract changes. The final median postoperative VA (at 2 years) in 25 gauge PPV group was 20/40 which was better than final visual outcomes for 20, and 23 gauge PPV groups (20/50, and 20/55 respectively). The different was not a statistically significant. MH closed successfully in 96 % (C3F8), and 88.1 % (SF6) (p = 0.063). Preoperative median VA was 20/100 in both groups of gas. At 6 months, 1 year, and 2 years postoperative median VAs did not differ significant between the 2 groups (p = 0.076, 0.343, and 0.309 respectively). MH closed successfully in (96.9 %) 12-14 % C3F8, and (95.3 %) 15-16 % C3F8 (p = 0.611). MH closed in (82.1 %) 18-20 % SF6, and (96.4 %) 22-26 % SF6 (p=0.053). Based on the results of this study, 20, 23, and 25 gauge of PPV have similar MH closure rates and VA outcomes. SF6 at 22-26 % or C3F8 at 12-14 % achieved maximum closure rates.
DETECTING AND INTERPRETING STATISTICAL LENSING BY ABSORBERS

We propose a method for detecting gravitational magnification of distant sources, such as quasars, due to absorber systems detected in their spectra. We first consider the use of metal absorption lines rather than Lyα lines; then we show how to relate the observed moments of the source magnitude distribution to the mass distribution of absorbers. In order to illustrate the feasibility of the method, we use a simple model to estimate the amplitude of the effect expected for Mg II absorption lines and show that their lensing signal might already be detectable in large surveys like the SDSS. Our model suggests that quasars behind strong Mg II absorbers are, on average, brightened by -0.05 to -0.2 mag due to magnification. One must therefore revisit the claim that, in magnitude-limited surveys, quasars with strong absorbers tend to be missed due to extinction effects. In addition to constraining the mass of absorber systems, applying our method will allow for the quantification of this bias.
Distinct Prion Strains Are Defined by Amyloid Core Structure and Chaperone Binding Site Dynamics

Summary Yeast prions are self-templating protein-based mechanisms of inheritance whose conformational changes lead to the acquisition of diverse new phenotypes. The best studied of these is the prion domain (NM) of Sup35, which forms an amyloid that can adopt several distinct conformations (strains) that produce distinct phenotypes. Using magic-angle spinning nuclear magnetic resonance spectroscopy, we provide a detailed look at the dynamic properties of these forms over a broad range of timescales. We establish that different prion strains have distinct amyloid structures, with many side chains in different chemical environments. Surprisingly, the prion strain with a larger fraction of rigid residues also has a larger fraction of highly mobile residues. Differences in mobility correlate with differences in interaction with the prion-partitioning factor Hsp104 in vivo, perhaps explaining strain-specific differences in inheritance.
Design of supervised classifiers using Boolean neural networks

In this paper we present two supervised pattern classifiers designed using Boolean neural networks. They are: 1) nearest-to-an-exemplar classifier; and 2) Boolean k-nearest neighbor classifier. The emphasis during the design of these classifiers was on simplicity, robustness, and the ease of hardware implementation. The classifiers use the idea of radius of attraction to achieve their goal. Mathematical analysis of the algorithms presented in the paper is done to prove their feasibility. Both classifiers are tested with well-known binary and continuous feature valued data sets yielding results comparable with those obtained by similar existing classifiers.