cssi/SciSciGPT-SciSciNet huggingface dataset:
A statistical approach for accurate detection of atrial fibrillation and flutter

We have developed an algorithm for real-time detection of atrial fibrillation (AF) and flutter (AFL) that relies on 4 statistical techniques (root mean square of successive differences, turning point ratio and Shannon entropy). For AFL detection we use a time-frequency based method via the complex demodulation technique to recognize a characteristic rhythm of AFL. We used the MIT-BIH Atrial Fibrillation database to train the algorithm and then tested it on the MIT-BIH Arrhythmia database. We achieved sensitivity (specificity) of 94% (95%) on the training set and 90 % (91%) on the test database for AF detection. We further tested the AF performance on 36 actual Holter files obtained from The ScottCare Corporation and achieved sensitivity and specificity of 95% and 95% respectively. AFL detection was tested on 2 files of the AFIB database and we achieved 97% sensitivity and 95% specificity. The ease of implementation and minimal memory and speed requirements make this algorithm ideal for on-chip or similar usage.
What Are Microfoundations

In the extant organizational, management, and strategy literatures there are now frequent calls for microfoundations. However, there is little consensus on what micro- foundations are and what they are not. In this paper we first (briefly) review the history of the microfoundations discussion and then discuss what microfoundations are and are not. We highlight four misconceptions or "half-truths" about microfoundations: (1) that microfoundations are psychology, human resources, or micro-organizational behavior, (2) that borrowed concepts constitute microfoundations, (3) that microfoundations lead to an infinite regress, and (4) that microfoundations deny the role of structure and institutions. We discuss both the partial truths and the misconceptions associated with the above understandings of microfoundations, and we argue that questions of social aggregation and emergence need to be center stage in any discussion of microfoundations. We link our arguments about microfoundations and aggregation with closely related calls for new areas of research, such as "behavioral strategy" and the domain of multilevel human capital research. We discuss various forms of social aggregation and also highlight associated opportunities for future research, with a specific focus on the origins of capabilities and competitive advantage.
Bis-ureidodeazapterin (Bis-DeAP) as a general route to supramolecular star polymers

Abstract Supramolecular recognition unit Bis-DeAP, 1, containing two high affinity hydrogen-bonding acceptor–acceptor–donor–donor (AADD) arrays was designed to self-assemble into cyclic assemblies. It was prepared through a highly scalable synthesis and was further functionalized with 2-bromo-2-methylpropanoyl bromide and used to initiate the polymerization of methylmethacrylate (MMA). Bis-DeAP–PMMA polymers quantitatively self-assembled into star polymers in toluene. In DMF Bis-DeAP–PMMA forms a mixture of star polymers and unassembled polymers. Bis-DeAP was also functionalized with polyethylene glycol (PEG) polymers. The Bis-DeAP–PEG polymers formed star polymers in DMF; however, higher molecular weight polymeric assembles that varied with concentration were observed in water. Mixing studies in toluene indicated that the self-assembled star polymers are kinetically stable and resist mixing even at elevated temperatures. In DMF, kinetically controlled structures are initially observed, however, mixing occurs at a faster rate and assembled star polymers show a decrease in polydispersity index (PDI) over time. In addition, Bis-DeAP functionalized PS and PMMA were mixed in DMF to generate a star copolymer through self-assembly.
Vertical Links Between Formal and Informal Financial Institutions

The paper investigates vertical linkages between formal and informal financial institutions. Specifically, it studies a policy that expands formal credit to informal lenders, in the hope that this will improve loan terms for borrowers who are shut out of the formal sector. Special attention is paid to the Philippines. It is argued that the effects of stronger vertical links depend on the form of lender competition. In particular, if the relationship between lenders is one of strategic cooperation (sustained by threats of reprisal in a repeated setting), an expansion of formal credit may worsen the terms faced by informal borrowers.
What Can Gauge-Gravity Duality Teach Us about Condensed Matter Physics?

I discuss the impact of gauge-gravity duality on our understanding of two classes of systems: conformal quantum matter and compressible quantum matter. The first conformal class includes systems, such as the boson Hubbard model in two spatial dimensions, which display quantum critical points described by conformal field theories. Questions associated with non-zero temperature dynamics and transport are difficult to answer using conventional field theoretic methods. I argue that many of these can be addressed systematically using gauge-gravity duality, and discuss the prospects for reliable computation of low frequency correlations. Compressible quantum matter is characterized by the smooth dependence of the charge density, associated with a global U(1) symmetry, upon a chemical potential. Familiar examples are solids, superfluids, and Fermi liquids, but there are more exotic possibilities involving deconfined phases of gauge fields in the presence of Fermi surfaces. I survey the compressible systems studied using gauge-gravity duality, and discuss their relationship to the condensed matter classification of such states. The gravity methods offer hope of a deeper understanding of exotic and strongly-coupled compressible quantum states.
Development of Bioavailability and Biokinetics Determination Methods for Organic Pollutants in Soil to Enhance In‐Situ and On‐Site Bioremediation

Determination of biodegradation rates of organics in soil slurry and compacted soil systems is essential for evaluating the efficacy of bioremediation for treatment of contaminated soils. In this paper, a systematic protocol has been developed for evaluating biokinetic and transport parameters in soil slurry and compacted soil bioreactors. The protocol involves abiotic evaluation of adsorption/desorption rates, and equilibria followed by the use of respirometry to determine biodegradation rates using soil slurry, wafer, and porous tube reactors. In the soil slurry reactor, mimicking ex-situ soil biotreatment, degradation occurs in the aqueous phase by suspended microorganisms and by immobilized microbiota present in the soil phase. In a soil wafer reactor, which consists of a thin layer of soil, biodegradation occurs primarily in the soil phase, as compared to the aqueous phase, which consists of free and bound water in and around the soil particles. The wafer reactor represents biotreatment using bioventing or land farming methods. In the porous tube reactor, rate of oxygen diffusion through the compacted soil affects the overall rate of biodegradation. The porous tube reactor represents in-situ biotreatment. Experiments were conducted to determine the cumulative oxygen uptake using an uncontaminated low organic carbon soil with phenol as the spiked contaminant. Detailed mathematical models were developed for each type of soil reactor (slurry, wafer, and porous tube), and these models were fitted to the cumulative oxygen uptake data to derive the best-fit transport and biokinetic parameters. Application of the transport and biokinetic parameters to determine the attainable treatment end points is discussed in this paper.
Theoretical Models for Supernovae

The results of recent numerical simulations of supernova explosions are presented and a variety of topics discussed. Particular emphasis is given to i) the nucleosynthesis expected from intermediate mass (10 MƟ 100 MƟ) of both Population I and III. In one dimension, nuclear burning following a ‘failed’ core bounce does not appear likely to lead to a supernova explosion although, in two dimensions, a combination of rotation and nuclear burning may do so. Near solar proportions of elements from neon to calcium and very brilliant optical displays may be created by ‘hypernovae’, the explosions of stars in the mass range 100 MƟ to 300 MƟ. Above ~ 300 MƟ a black hole is created by stellar collapse following carbon ignition. Still more massive stars may be copious producers of 4He and 14N prior to their collapse on the pair instability.
Rationalizing Choice with Multi-Self Models

This paper studies a class of multi-self decision-making models proposed in economics, psychology, and marketing. In this class, choices arise from the set-dependent aggregation of a collection of utility functions, where the aggregation procedure satises some simple properties. We propose a method for characterizing the extent of irrationality in a choice behavior, and use this measure to provide a lower bound on the set of choice behaviors that can be rationalized with n utility functions. Under an additional assumption (scale-invariance), we show that generically at most ve \reasons" are needed for every \mistake."
Design and Characterization of a Hypervelocity Expansion Tube Facility

We report on the design and characterization of a 152 mm diameter expansion tube capable of accessing a range of high enthalpy test conditions with Mach numbers up to 7.1 for aerodynamic studies. Expansion tubes have the potential to offer a wide range of test flow conditions as gas acceleration is achieved through interaction with an unsteady expansion wave rather than expansion through a fixed area ratio nozzle. However, the range of test flow conditions is in practice limited by a number of considerations such as short test time and large amplitude flow disturbances. We present a generalized design strategy for small-scale expansion tubes. As a starting point, ideal gas dynamic calculations for optimal facility design to maximize test time at a given Mach number test condition are presented, together with a correction for the expansion head reflection through a non-simple region. A compilation of practical limitations that have been identified for expansion tube facilities such as diaphragm rupture and flow disturbance minimization is then used to map out a functional design parameter space. Experimentally, a range of test conditions have been verified through pitot pressure measurements and analysis of schlieren images of flow over simple geometries. To date there has been good agreement between theoretical and experimental results.
Damage-Mitigating Control of Mechanical Systems: Part II—Formulation of an Optimal Policy and Simulation

The objective of damage-mitigating control introduced in the first part of this two-part paper is to achieve high performance without overstraining the mechanical structures. The major benefits its an increase in the functional life of critical plant components along with enhanced safety, operational reliability, and availability. Specifically, a methodology for modeling fatigue damage has been developed as an augmentation to control and diagnostics of complex dynamic processes such as advanced aircraft, spacecraft, and power plants
Patterning of single walled carbon nanotubes using a low-fluence excimer laser photoablation process

Carbon nanotube films were patterned by an excimer laser projection photoablation process at low incident energy conditions. The carbon nanotubes were deposited on a quartz substrate and then a conventional photoresist was coated on it as a photoablation assistor. The photoresist and the carbon nanotubes were simultaneously patterned by the projection photoablation process, and then the photoresist was removed. It was possible to make clean patterns of carbon nanotubes even though the incident fluence on the carbon nanotubes was significantly lower than the threshold energy otherwise needed for their direct ablation.
Random Matrices: Universality of Local Eigenvalue Statistics up to the Edge

This is a continuation of our earlier paper (Tao and Vu, http://arxiv.org/abs/0908.1982v4[math.PR], 2010) on the universality of the eigenvalues of Wigner random matrices. The main new results of this paper are an extension of the results in Tao and Vu (http://arxiv.org/abs/0908.1982v4[math.PR], 2010) from the bulk of the spectrum up to the edge. In particular, we prove a variant of the universality results of Soshnikov (Commun Math Phys 207(3):697–733, 1999) for the largest eigenvalues, assuming moment conditions rather than symmetry conditions. The main new technical observation is that there is a significant bias in the Cauchy interlacing law near the edge of the spectrum which allows one to continue ensuring the delocalization of eigenvectors.
Infinite log-concavity: Developments and conjectures

Given a sequence (a"k)=a"0,a"1,a"2,... of real numbers, define a new sequence L(a"k)=(b"k) where b"k=a"k^2-a"k"-"1a"k"+"1. So (a"k) is log-concave if and only if (b"k) is a nonnegative sequence. Call (a"k)infinitely log-concave if L^i(a"k) is nonnegative for all i>=1. Boros and Moll conjectured that the rows of Pascal's triangle are infinitely log-concave. Using a computer and a stronger version of log-concavity, we prove their conjecture for the nth row for all n=<1450. We also use our methods to give a simple proof of a recent result of Uminsky and Yeats about regions of infinite log-concavity. We investigate related questions about the columns of Pascal's triangle, q-analogues, symmetric functions, real-rooted polynomials, and Toeplitz matrices. In addition, we offer several conjectures.
TEM Studies of Protective Al Coatings on Kapton H

Polymeric materials undergo rapid erosion when exposed to the harsh low-earth-orbit (LEO) environment. Coatings can reduce the erosion rate of polyimide Kapton from atomic oxygen (AO) attack. Specifically, we are investigating how thin Al coatings can protect Kapton. Protective Al layers with variations in layer thickness and growth conditions were deposited on Kapton H. The quality of these protective coatings were evaluated by mass loss measurement and compared to Kapton alone and the SiO2 coating, where dramatically decreased erosion rate was noted. To understand how these coatings protect Kapton as well as how the AO interacts with the coatings, we are investigating the microstructure of these coated materials by plane view and cross-sectional transmission electron microscopy (TEM) methods. To understand the AO degradation mechanism, we attempted to correlate the mass loss with growth conditions and microstructures. We noted a slight improvement in erosion resistance of the Al coating due to the presence of the dendrimer, but a major improvement when the Al coating is deposited under ultrahigh vacuum conditions.
Salvage Percutaneous Nephrolithotomy: Analysis of Outcomes following Initial Treatment Failure.

Purpose: Percutaneous nephrolithotomy has high potential for morbidity or failure. There are limited data regarding risk factors for failure and to our knowledge no published reports of surgical outcomes in patients with prior failed attempts at percutaneous stone removal.Materials and Methods: We identified patients referred to 3 medical centers after prior failed attempts at percutaneous nephrolithotomy. A retrospective chart review was performed to analyze reasons for initial failure and outcomes of salvage percutaneous nephrolithotomy. Outcomes were compared to those in a prospectively maintained database of more than 1,200 patients treated with a primary procedure.Results: Salvage percutaneous nephrolithotomy was performed in 31 patients. Unsuitable access to the stone was the reason for failure in 80% of cases. Other reasons included infection, bleeding and inadequate instrument availability in 6.5% of cases each. Compared to patients who underwent primary percutaneous nephrolithotomy those treated ...
DECISION LISTS FOR LEXICAL AMBIGUITY RESOLUTION: Application to Accent Restoration in Spanish and French

This paper presents a statistical decision procedure for lexical ambiguity resolution. The algorithm exploits both local syntactic patterns and more distant collocational evidence, generating an efficient, effective, and highly perspicuous recipe for resolving a given ambiguity. By identifying and utilizing only the single best disambiguating evidence in a target context, the algorithm avoids the problematic complex modeling of statistical dependencies. Although directly applicable to a wide class of ambiguities, the algorithm is described and evaluated in a realistic case study, the problem of restoring missing accents in Spanish and French text. Current accuracy exceeds 99% on the full task, and typically is over 90% for even the most difficult ambiguities.
Defining Best Practice in Care and Protection of Children in Crisis-Affected Settings: A Delphi Study

Thirty specialists in humanitarian work supporting the care and protection of children in crisis settings completed a 3-phase Delphi consultation. Proposals of best practice were elicited, reviewed, and rated by participants. A high level of consensus support was reached for 55 statements. These statements emphasized utilization of existing resources, participation, and inclusivity. The influences of resilience theory, social ecology, and cultural sensitivity were clearly evident. The utilization of developmental theory could be strengthened in relation to more differentiated understanding of the operation of protective influences and conceptualization of such influences in terms of ‘‘adaptive systems.’’ Wider research engagement by development scientists in diverse cultural settings and clear formulation of findings for practitioners and policy makers would further support evidence-based humanitarian practice.
A Doctor's First, and Last, Responsibility is to Care Comment on "Denial of Treatment to Obese Patients-the Wrong Policy on Personal Responsibility for Health".

The obesity epidemic raises important and complex issues for clinicians and policy-makers, such as what clinical and public health measures will be most effective and most ethically-sound. While Nir Eyal’s analysis of these issues is very helpful and while he correctly concludes that “conditioning the very aid that patients need in order to become healthier on success in becoming healthier” is wrong, further discussions of these issues must include unequivocal support for safeguarding the fundamental moral basis of the doctor-patient relationship. Regardless of any patients’ failures to demonstrate effective responsibility for their own health, each patient needs and deserves a physician whose caring is never in doubt. Policy-makers need to ensure that our health systems always make this a top priority.
Existence and uniqueness of equilibrium in nonoptimal unbounded infinite horizon economies

Abstract In applied work in macroeconomics and finance, nonoptimal infinite horizon economies are often studied in which the state-space is unbounded. Important examples of such economies are single-sector growth models with production externalities, valued fiat money, monopolistic competition, and/or distortionary government taxation. Although sufficient conditions for existence and uniqueness of Markovian equilibrium are well known for the compact state space case, no similar sufficient conditions exist for unbounded growth. This paper provides such a set of sufficient conditions, and presents a computational algorithm that will prove asymptotically consistent when computing Markovian equilibrium.
Transfection by electroporation.

Electroporation-the use of high-voltage electric shocks to introduce DNA into cells-can be used with most cell types, yields a high frequency of both stable transformation and transient gene expression, and, because it requires fewer steps, can be easier than alternate techniques. This unit describes electroporation of mammalian cells, including ES cells for the preparation of knock-out, knock-in, and transgenic mice. Protocols are described for the use of electroporation in vivo to perform gene therapy for cancer therapy and DNA vaccination. Also described are modifications for preparation and transfection of plant protoplasts. © 2018 by John Wiley & Sons, Inc.
Determinants and Effects of Subjectivity in Incentives

This study examines two questions: When do firms make greater use of subjectivity in awarding bonuses? What are the effects of subjectivity on employee pay satisfaction and firm performance? We examine these questions using data from a sample of 526 department managers in 250 car dealerships. First, the findings suggest that subjective bonuses are used to complement perceived weaknesses in quantitative performance measures and to provide employees insurance against downside risk in their pay. Specifically, use of subjective bonuses is positively related to: (1) the extent of long‐term investments in intangibles; (2) the extent of organizational interdependencies; (3) the extent to which the achievability of the formula bonus target is both difficult and leads to significant consequences if not met; and (4) the presence of an operating loss. Second, we find that the effects of subjective bonuses on pay satisfaction, productivity, and profitability are larger the greater the manager's tenure, consistent wit...
Broadcasting algorithms in radio networks with unknown topology

In this paper we present new randomized and deterministic algorithms for the classical problem of broadcasting in radio networks with unknown topology. We consider directed n-node radio networks with specified eccentricity D (maximum distance from the source node to any other node). Bar-Yehuda et al. presented an algorithm that for any n-node radio network with eccentricity D completes the broadcasting in O(D log n + log2 n) time, with high probability. This result is almost optimal, since as it has been shown by Kushilevitz and Mansour and Alon et al., every randomized algorithm requires Ω (D log(n/D) + log2 n) expected time to complete broadcasting.Our first main result closes the gap between the lower and upper bound: we describe an optimal randomized broadcasting algorithm whose running time complexity is O(D log (n/D + log2 n), with high probability. In particular, we obtain a randomized algorithm that completes broadcasting in any n-node radio network in time O(n), with high probability.The main source of our improvement is a better "selecting sequence" used by the algorithm that brings some stronger property and improves the broadcasting time. Two types of "selecting sequences" are considered: randomized and deterministic ones. The algorithm with a randomized sequence is easier (more intuitive) to analyze but both randomized and deterministic sequences give algorithms of the same asymptotic complexity.
Workspace analysis of multibody mechanical systems using continuation methods

A new approach to numerical analysis of workspaces of multibody mechanical systems is presented, based on manifold theory and computational continuation methods. Generalized coordinates that define the kinematics of a system are classified and interpreted from an input-output point of view. Boundaries of workspaces, which depend on the classification of generalized coordinates, are defined as sets of points for which Jacobian matrices of the kinematic equations are row rank deficient. This criterion generalizes the conventional determinant criteria for applications with square Jacobian matrices. Numerical methods for tracing families of one dimensional trajectories on a workspace boundary are outlined. Open and closed loop manipulator examples are analyzed, using a manifold mapping computer program.
Engineered ascorbate peroxidase as a genetically encoded reporter for electron microscopy

Electron microscopy (EM) is the standard method for imaging cellular structures with nanometer resolution, but existing genetic tags are inactive in most cellular compartments or require light and can be difficult to use. Here we report the development of 'APEX', a genetically encodable EM tag that is active in all cellular compartments and does not require light. APEX is a monomeric 28-kDa peroxidase that withstands strong EM fixation to give excellent ultrastructural preservation. We demonstrate the utility of APEX for high-resolution EM imaging of a variety of mammalian organelles and specific proteins using a simple and robust labeling procedure. We also fused APEX to the N or C terminus of the mitochondrial calcium uniporter (MCU), a recently identified channel whose topology is disputed. These fusions give EM contrast exclusively in the mitochondrial matrix, suggesting that both the N and C termini of MCU face the matrix. Because APEX staining is not dependent on light activation, APEX should make EM imaging of any cellular protein straightforward, regardless of the size or thickness of the specimen.
The Magnetic Field in Taurus Probed by Infrared Polarization

We present maps of the plane-of-sky magnetic field within two regions of the Taurus molecular cloud: one in the dense core L1495/B213 filament and the other in a diffuse region to the west. The field is measured from the polarization of background starlight seen through the cloud. In total, we measured 287 high-quality near-infrared polarization vectors in these regions. In L1495/B213, the percent polarization increases with column density up to AV ~ 9 mag, the limits of our data. The radiative torques model for grain alignment can explain this behavior, but models that invoke turbulence are inconsistent with the data. We also combine our data with published optical and near-infrared polarization measurements in Taurus. Using this large sample, we estimate the strength of the plane-of-sky component of the magnetic field in nine subregions. This estimation is done with two different techniques that use the observed dispersion in polarization angles. Our values range from 5 to 82 μG and tend to be higher in denser regions. In all subregions, the critical index of the mass-to-magnetic flux ratio is sub-unity, implying that Taurus is magnetically supported on large scales (~2 pc). Within the region observed, the B213 filament takes a sharp turn to the north and the direction of the magnetic field also takes a sharp turn, switching from being perpendicular to the filament to becoming parallel. This behavior can be understood if we are observing the rim of a bubble. We argue that it has resulted from a supernova remnant associated with a recently discovered nearby gamma-ray pulsar.
An analysis of the membrane deflection experiment used in the investigation of mechanical properties of freestanding submicron thin films

Abstract In this paper we investigate, both experimentally and theoretically, the competition between different failure mechanisms (stretching, bending and curvature localization) in freestanding submicron thin films commonly used in micro-electromechanical systems. Microstructures made of elastic-brittle materials such as ultrananocrystalline diamond, diamond like carbon and silicon nitride, as well as elastic–plastic materials such as gold, aluminum, and copper, are tested by means of the membrane deflection experiment developed at Northwestern University. Evidence of competition between different failure modes has been found for the investigated elastic-brittle materials. The phenomenon is dependent on specimen size and shape. By contrast, in the case of elastic–plastic materials, failure due to stretching was found to be the dominant mechanism. An analytical model is proposed to rationalize the experimental data and to provide dimensionless parameters able to describe the competition between different failure mechanisms. These dimensionless parameters are particularly useful in the design of specimens employed in the MDE technique.
The impact of minimum age of employment regulation on child labor and schooling

Promoting minimum age of employment regulation has been a centerpiece in child labor policy for the last 15 years. If enforced, minimum age regulation would change the age profile of paid child employment. Using micro-data from 59 mostly low-income countries, we observe that age can explain less than one percent of the variation in child participation in paid employment. In contrast, child-invariant household attributes account for 63 percent of the variation in participation in paid employment. While age may explain little of the variation in paid employment, minimum age of employment regulation could simultaneously impact time allocation. We do not observe evidence consistent with enforcement of minimum age regulation in any country examined, although light work regulation appears to have been enforced in one country. J22, O15, J88, K42
Microwave holographic metrology for antenna diagnosis

Advances in antenna diagnostic methodologies have been very significant in recent years. In particular, microwave holographic diagnostic techniques have been applied very successfully in improving the performance of reflector and array antennas. These techniques use the knowledge of the measured amplitude and phase of the antenna radiated fields and then take advantage of the existing Fourier transform relationships between the radiated fields and the effective aperture or current distribution to eventually determine the reflector surface or array excitation coefficients anomalies. In this paper an overview of the recent developments in applying microwave holography is presented. The theoretical, numerical and measurement aspects of this technique is detailed by providing representative results.
Nonfixed Retirement Age for University Professors: Modeling Its Effects on New Faculty Hires

We model the set of tenure-track faculty members at a university as a queue, where “customers” in queue are faculty members in active careers. Arrivals to the queue are usually young, untenured assistant professors, and departures from the queue are primarily those who do not pass a promotion or tenure hurdle and those who retire. There are other less-often-used ways to enter and leave the queue. Our focus is on system effects of the elimination of mandatory retirement age. In particular, we are concerned with estimating the number of assistant professor slots that annually are no longer available because of the elimination of mandatory retirement. We start with steady-state assumptions that require use of Little's Law of Queueing, and we progress to a transient model using system dynamics. We apply these simple models using available data from our home university, the Massachusetts Institute of Technology.
Adjoint for operators in Banach spaces

In this paper we show that a result of Gross and Kuelbs, used to study Gaussian measures on Banach spaces, makes it possible to construct an adjoint for operators on separable Banach spaces. This result is used to extend well-known theorems of von Neumann and Lax. We also partially solve an open problem on the existence of a Markushevich basis with unit norm and prove that all closed densely defined linear operators on a separable Banach space can be approximated by bounded operators. This last result extends a theorem of Kaufman for Hilbert spaces and allows us to define a new metric for closed densely defined linear operators on Banach spaces. As an application, we obtain a generalization of the Yosida approximator for semigroups of operators.
Triple collision in Newtonian gravitational systems

Abstract : The author describes the motions of Newtonian gravitational systems near triple collision.
New Low-Mass Stars and Brown Dwarfs with Disks in Lupus

Using the Infrared Array Camera and the Multiband Imaging Photometer aboard the Spitzer Space Telescope, we have obtained images of the Lupus 3 star-forming cloud at 3.6, 4.5, 5.8, 8.0, and 24 μm. We present photometry in these bands for the 41 previously known members that are in our images. In addition, we have identified 19 possible new members of the cloud based on red 3.6-8.0 μm colors that are indicative of circumstellar disks. We have performed optical spectroscopy on six of these candidates, all of which are confirmed as young low-mass members of Lupus 3. The spectral types of these new members range from M4.75 to M8, corresponding to masses of 0.2-0.03 M☉ for ages of ~1 Myr according to theoretical evolutionary models. We also present optical spectroscopy of a candidate disk-bearing object in the vicinity of the Lupus 1 cloud, 2M 1541-3345, which Jayawardhana & Ivanov recently classified as a young brown dwarf (M ~ 0.03 M☉) with a spectral type of M8. In contrast to their results, we measure an earlier spectral type of M5.75 ± 0.25 for this object, indicating that it is probably a low-mass star (M ~ 0.1 M☉). In fact, according to its gravity-sensitive absorption lines and its luminosity, 2M 1541-3345 is older than members of the Lupus clouds (τ ~ 1 Myr) and instead is probably a more evolved pre-main-sequence star that is not directly related to the current generation of star formation in Lupus.
New integrable lattice models from Fuss-Catalan algebras

Abstract We construct new hyperbolic solutions of the Yang-Baxter equation, using the Fuss-Catalan algebras, a set of multi-colored versions of the Temperley-Lieb algebra, recently introduced by Bisch and Jones. These lead to new two-dimensional integrable lattice models, describing dense gases of colored loops.
BEHAVIORAL CONTROL OF OVEREATING

Onnsrn is well-recognized as a major health hazard. Only two common characteristics have been observed in obese persons: a tendency to overeat and a tendency to underexercise (U.S. Public Health Service, undated). While obesity has been ascribed to various causes (Bychowski, 1950; Hamburger, 1951; Deri, 1955; Stunkard, 1959; Mendelson, 1966), the treatment of overeating has been successful when it is based solely upon a tunctional analysis of the maladaptive response (Ferster et al., 1962). The present paper presents Ferster’s approach in somewhat modified form and reports upon the clinical results to date. SELF-CONTROL Man clearly controls his own behavior so as to achieve his own objectives. The source of this control is commonly ascribed to central adaptive mechanisms ranging from the ego to the conscience. From a behavioral point of view, self-control is an inference drawn from the functional relationships among observable responses (Bijou and Baer, 1961). The behavioral processes involved in a person’s control of himself are the same as those one would use in controlling the behavior of others (Skinner, 1953). The first step in self-control is a precise analysis of the response to be controlled and its antecedent and consequent conditions. An analysis of overeating would naturally include a precise description of the topography of the response, the conditions under which it occurs, and its consequences. The second step is the identification of behavior which facilitates eating a proper amount of food (including behavior which interferes with overeating). The third step is the identification of positive or negative reinforcers which control these behavior patterns. A reinforcer can be identified for every response, using Premack’s principle (“Of any two responses, the more probable response will reinforce the less probable one;” Premack, 1965). Thus a reinforcer is always available for any desired response, independent of the topography of that response. The fourth step requires the application of the reinforcement to alter the probability of the preselected response (Homme, 1965). The outcome of self-control can be termed “contingency management*’ and is designed to increase the frequency of desired overt or covert responses while decreasing the frequency of undesired responses.
Blocking: new examples and properties of products

We say that a pair of points x and y is secure if there exists a finite set of blocking points such that any geodesic between x and y passes through one of the blocking points. The main point of this paper is to exhibit new examples of blocking phenomena in both the manifold and the billiard table settings. In approaching this, we study whether a product of secure configurations (or manifolds) is also secure. We introduce the concept of midpoint security which requires that the geodesic reaches a blocking point exactly at its midpoint. We prove that products of midpoint secure configurations are midpoint secure. On the other hand, we construct a compact C1 surface which contains secure configurations that are not midpoint secure. This surface provides the first example of an insecure product of secure configurations, and generates billiard tables with similar blocking behavior.
Observations on Unstable Quantons, Hyperplane Dependence and Quantum Fields

Please follow the link below for the most recent version of this paper: http://philsci-archive.pitt.edu/archive/00004667/
Reliability analysis in intelligent machines

Given an explicit task to be executed, an intelligent machine must be able to find the probability of success, or reliability, of alternative control and sensing strategies. By using concepts for information theory and reliability theory, new techniques for finding the reliability corresponding to alternative subsets of control and sensing strategies are proposed such that a desired set of specifications can be satisfied. The analysis is straightforward, provided that a set of Gaussian random state variables is available. An example problem illustrates the technique, and general reliability results are presented for visual servoing with a computed torque-control algorithm. Moreover, the example illustrates the principle of increasing precision with decreasing intelligence at the execution level of an intelligent machine. >
Inertial effects on viscous fingering in the complex plane

We present a nonlinear unsteady Darcy's equation which includes inertial effects for flows in a porous medium or Hele-Shaw cell and discuss the conditions under which it reduces to the classical Darcy's law. In the absence of surface tension we derive a generalized Polubarinova–Galin equation in a circular geometry, using the method of conformal mapping. The linear stability of the base-flow state is examined by perturbing the corresponding conformal map. We show that inertia always has a tendency to stabilize the interface, regardless of whether a less viscous fluid is displacing a more viscous fluid or vice versa.
Status Preference, Wealth and Dynamics in the Open Economy

. The implications of status preference in a simple open economy model are investigated in this paper. The open economy is modeled as a continuum of identical representative agents who have preferences over consumption and status. In the paper status is identified as relative wealth, which takes the form of relative holdings international financial assets. A symmetric macroeconomic equilibrium is derived in which status is the source of transitional dynamics for domestic consumption and the current account balance. This result illustrates another way to combine transitional dynamics with interior equilibria in the small open economy Ramsey model with perfect capital mobility. We also show that status preference plays a critical role in influencing the open economy's adjustment to government expenditure and world interest rate shocks.
DOMAIN DECOMPOSITION METHODS IN COMPUTATIONAL FLUID DYNAMICS

The divide-and-conquer paradigm of iterative domain decomposition, or substructuring, has become a practical tool in computational fluid dynamic applications because of its flexibility in accommodating adaptive refinement through locally uniform (or quasi-uniform) grids, its ability to exploit multiple discretizations of the operator equations, and the modular pathway it provides towards parallelism. These features are illustrated on the classic model problem of flow over a backstep using Newton's method as the nonlinear iteration. Multiple discretizations (second-order in the operator and first-order in the preconditioner) and locally uniform mesh refinement pay dividends separately, and they can be combined synergistically. Sample performance results are included from an Intel iPSC/860 hypercube implementation.
A tabu search heuristic procedure for the capacitated facility location problem

A tabu search heuristic procedure is developed, implemented and computationally tested for the capacitated facility location problem. The procedure uses different memory structures. Visited solutions are stored in a primogenitary linked quad tree. For each facility, the recent move at which the facility changed its status and the frequency it has been open are also stored. These memory structures are used to guide the main search process as well as the diversification and intensification processes. Lower bounds on the decreases of total cost are used to measure the attractiveness of the moves and to select moves in the search process. A specialized network algorithm is developed to exploit the problem structure in solving transportation problems. Criterion altering, solution reconciling and path relinking are used to perform intensification functions. The performance of the procedure is tested through computational experiments using test problems from the literature and new test problems randomly generated. It found optimal solutions for almost all test problems from the literature. As compared to the heuristic method of Lagrangean relaxation with improved subgradient scheme, the tabu search heuristic procedure found much better solutions using much less CPU time.
Image computations on reconfigurable VLSI arrays

The authors consider image computations on a mesh with reconfigurable bus (reconfigurable mesh). The architecture consists of an array of processors overlaid with a reconfigurable bus system. The reconfiguration scheme can be used to dynamically obtain various interconnection patterns among the processor elements. The reconfiguration scheme supports several parallel techniques developed on the CRCW PRAM (concurrent read, concurrent write parallel random-access machine) model, leading to asymptotically superior solution times to image problems compared to those on the mesh with multiple broadcasting, the mesh with multiple buses, the mesh-of-trees, and the pyramid computer. >
Isotope edited NMR studies of glycosidases: design and synthesis of a novel glycosidase inhibitor.

Abstract N - 13 C-methyl-deoxynojirimycin was synthesized and used in isotope-edited NMR studies to probe the binding site of an α-glucosidase. Results from this analysis led to the design and preparation of a novel α-glucosidase inhibitor, N -glycyl deoxynojirimycin.
Does It Matter Where Countries Are? Proximity to Knowledge, Markets and Resources, and MNE Location Choices

We suggest that the proximity of a country to other countries is a factor that affects its choice as a multinational enterprise (MNE) location. We introduce the concept of a country's proximity to the global distribution of knowledge, markets, and resources, and frame this concept as a function of both geographic distance and the worldwide spatial distribution of these factors. We test our location model on a data set comprising 138,050 investments undertaken by U.S. MNEs worldwide. Our findings show that the proximity of a country to the rest of the world has a positive impact on MNEs choosing that country as a location. Proximity to the world's knowledge and markets are stronger drivers of location choice than is proximity to the world's resources, after accounting for the country's own endowments. Larger firms are able to benefit more from remote locations than smaller firms are.
Searching for memories, sudoku, implicit check bits, and the iterative use of not-always-correct rapid neural computation

The algorithms that simple feedback neural circuits representing a brain area can rapidly carry out are often adequate to solve easy problems but for more difficult problems can return incorrect answers. A new excitatory-inhibitory circuit model of associative memory displays the common human problem of failing to rapidly find a memory when only a small clue is present. The memory model and a related computational network for solving Sudoku puzzles produce answers that contain implicit check bits in the representation of information across neurons, allowing a rapid evaluation of whether the putative answer is correct or incorrect through a computation related to visual pop-out. This fact may account for our strong psychological feeling of right or wrong when we retrieve a nominal memory from a minimal clue. This information allows more difficult computations or memory retrievals to be done in a serial fashion by using the fast but limited capabilities of a computational module multiple times. The mathematics of the excitatory-inhibitory circuits for associative memory and for Sudoku, both of which are understood in terms of energy or Lyapunov functions, is described in detail.
A near-optimal memoryless online algorithm for FIFO buffering two packet classes

We consider scheduling packets with values in a capacity-bounded buffer in an online setting. In this model, there is a buffer with limited capacity B. At any time, the buffer cannot accommodate more than B packets. Packets arrive over time. Each packet has a non-negative value. Packets leave the buffer only because they are either sent or dropped. Those packets that have left the buffer will not be reconsidered for delivery any more. In each time step, at most one packet in the buffer can be sent. The order in which the packets are sent should comply with the order of their arrival time. The objective is to maximize the total value of the packets sent in an online manner. In this paper, we study a variant of this FIFO buffering model in which a packet's value is either 1 or @a>1. We present a deterministic memoryless 1.304-competitive algorithm. This algorithm has the same competitive ratio as the one presented in Lotker and Patt-Shamir [Z. Lotker, B. Patt-Shamir, Nearly optimal FIFO buffer management for DiffServ, in: Proceedings of the 21st Annual ACM Symposium on Principles of Distributed Computing, PODC, 2002, pp. 134-142; Z. Lotker, B. Patt-Shamir, Nearly optimal FIFO buffer management for DiffServ, Computer Networks 17 (1) (2003) 77-89]. However, our algorithm is simpler and does not employ any marking bits. The idea used in our algorithm is novel and different from all previous approaches that have been applied for the general model and its variants. We do not proactively preempt one packet when a new packet arrives. Instead, we may preempt more than one 1-value packet at the time when the buffer contains sufficiently many @a-value packets.
Optimal terminal wealth under partial information: Both the drift and the volatility driven by a discrete time Markov chain

We consider a multi-stock market model. The stock price process satisfies a stochastic differential equation where both the drift and the volatility are driven by a discrete-time Markov chain of finite states. Not only the underlying Brownian motion but also the Markov chain in the stochastic differential equation are assumed to be unobservable. Investors can observe the stock price process only. The main result of this paper is that we derive the approximation of the optimal trading strategy and the corresponding optimal expected utility function from terminal wealth.
Polio vaccines and the origin of AIDS

Although mass vaccination programs have resulted in the eradication of a number of human infectious diseases, vaccine contamination has been a persistent concern. In particular, it is now known that the early polio vaccines were contaminated with at least one monkey virus, SV40. The transfer of monkey viruses to man via contaminated vaccines is particularly relevant to the acquired immunodeficiency syndrome (AIDS), since the causative agent of AIDS, human immunodeficiency virus (HIV), is thought to be derived from a simian precursor virus. Furthermore, human infection with this virus appears to be a relatively recent event. We hypothesize that the AIDS pandemic may have originated with a contaminated polio vaccine that was administered to inhabitants of Equatorial Africa from 1957 to 1959. The mechanism of evolution of HIV from this vaccine remains to be determined.