cssi/SciSciGPT-SciSciNet huggingface dataset:
Control system experiments at home

Most mechanical engineering curricula include courses in system dynamics, controls, mechatronics, and vibrations, but these courses often do not have a laboratory component. Even if there is such a component, laboratory access is often limited, and thus there is a need to increase students' laboratory experience. This paper addresses the development and testing of instructional material in the form of take-home hardware kits and software that can be used to perform control system experiments at home. The students are given a compact, low-cost hardware kit and software with which they can perform an experiment at home using only their PC/laptop. The kit consists of three components. These are: a hardware interface board which interfaces with the student's PC and with the experiment hardware, a Windows-based user interface program that the students download to their computer, and the experimental setup. Five experiments have been developed. Here we report on two of these experiments that involve control systems: a DC motor/tachometer system and a heater/temperature sensor system. Administration of the kits in several mechanical engineering courses has shown that the kits were effective in improving student understanding of key concepts.
Calibrator Design for the COBE* Far Infrared Absolute Spectrophotometer (FIRAS)

The photometric errors of the external calibrator for the Far Infrared Absolute Spectrophotometer (FIRAS) instrument on the COBE are smaller than the measurement errors on the cosmic microwave background radiation (CMBR) spectrum (typically 0.02 MJy sr-1, 1 σ) and smaller than 0.01% of the peak brightness of the CMB. The calibrator is a reentrant cone, shaped like a trumpet mute, made of Eccosorb iron-loaded epoxy. It fills the entire beam of the instrument and is the source of its accuracy. Its known errors are caused by reflections, temperature gradients, and leakage through the material and around the edge. Estimates and limits are given for all known error sources. Improvements in understanding the temperature measurements of the calibrator allow an improved CMB temperature determination of 2.725±0.002 K.
Opportunistic and cooperative spatial multiplexing in MIMO ad hoc networks

With the fast progress of multiple-input-multiple-output (MIMO) technology and its growing applications in networks, it is important to develop techniques to enable more efficient MIMO network communications. However, it is very challenging to coordinate node transmissions in a MIMO-based ad hoc network. In this work, we propose schemes that take advantage of the meshed topology of ad hoc networks to fully exploit the multiuser diversity and spatial diversity in order to maximize the data rate of the network while supporting different transmission priorities, reducing transmission delay, and ensuring fair transmissions among nodes. We formulate a concrete physical model and present cross-layer centralized and distributed scheduling algorithms that exploit physical-layer channel information to opportunistically schedule cooperative spatial multiplexed transmissions between nodes. We also propose a new MAC scheme to support our distributed algorithm. The performance of our algorithms are studied through extensive simulations, and the results demonstrate that our algorithms are very effective and can significantly increase the network throughput while reducing the transmission delay.
A non-associative arithmetic for shapes of channel networks

The purpose of this paper is to describe a method for analysis of one type of pictorial information that is abstracted from maps. The picture is a line diagram or graph that, in the language of graph theory, is a planted plane tree in which each vertex has a valency 1 or 3. In hydrology and geomorphology this type of graph is interpreted as a channel network that encompasses the topological properties of the network of rivers and streams comprising a drainage system. A recent survey paper by Dacey identifies a large number of properties of channel networks. Considering that many of these properties are clearly displayed by sketches of channel networks, the mathematical derivations seem unnecessarily complicated. This disparity in level of difficulty may reflect that the pictorial representation of a graph has a structure that is more amenable to analysis than does the conventional linguistic (i.e., mathematical) representation.
Detection of a narrow-band noise as a function of its interaural correlation

The detectability of a narrow-band noise is shown to be a function of the interaural correlation of both the signal and the masker. The maximal release from masking occurs when the addition of the signal results in a reduction in the correlation of the masking noise. The results show that people are far more sensitive to a decrease in the correlation between the stimuli at the two ears than to an increase.
Dowry and Intrahousehold Bargaining: Evidence from China

This paper analyzes the relationship between a woman's intrahousehold bargaining position and her welfare within marriage using household data from rural China. Simultaneity problems are overcome by using dowry to proxy for bargaining position. Omitted variable bias is addressed by using grain shocks in the year preceding marriage as an instrument for dowry. Instrumented dowry positively impacts numerous measures of a wife's welfare, including household purchases, the time allocation of household members, and the woman's satisfaction with life, offering strong evidence in support of collective models of the household.
Evaluation of Ice-Adhesion Strength on Erosion-Resistant Materials

Ice-adhesion properties were evaluated for coating systems based on titanium nitride applied via cathodic-arc physical vapor deposition developed for rotorcraft erosion caps. The ice-adhesion strength of titanium nitride and titanium aluminum nitride was determined experimentally and compared to the ice-adhesion strength of uncoated metallic materials currently used on rotor-blade leading-edge caps: stainless steel 430, Inconel 625, and titanium grade 2. Environmental and material parameters were investigated to identify which were most influential on impact ice-adhesion strength. The effects of median volumetric diameter of the cloud droplets, liquid water content of the cloud, ambient temperature, surface roughness, and material grain direction were tested on stainless steel 430. Tests revealed that surface roughness and temperature have the greatest effect on ice-adhesion strength. There was an increase in adhesion strength of 670% from −8 to −16 °C and 250% increase from 0.61 to 2.67Ra μm. An increas...
A distributed logic for Networked Cyber-Physical Systems

Abstract We describe a distributed logical framework designed to serve as a declarative semantic foundation for Networked Cyber-Physical Systems. The framework provides notions of facts and goals that include interactions with the environment via external goal requests, observations that generate facts, and actions that achieve goals. Reasoning rules are built on a partially ordered knowledge-sharing model for loosely coupled distributed computing. The logic supports reasoning in the context of dynamically changing facts and system goals. It can be used both to program systems and to reason about possible scenarios and emerging properties. The underlying reasoning framework is specified in terms of constraints that must be satisfied, making it very general and flexible. Inference rules for an instantiation to a specific local logic (Horn clause logic) are given as a concrete example. The key novel features are illustrated with snippets from an existing application—a theory for self-organizing robots performing a distributed surveillance task. Traditional properties of logical inference and computation are reformulated in this novel context, and related to features of system design and execution. Proofs are outlined for key properties corresponding to soundness, completeness, and termination. Finally, the framework is compared to other formal systems addressing concurrent/distributed computation.
A MANOMETRIC METHOD FOR THE DETERMINATION OF OXYGEN IN ORGANIC COMPOUNDS

A vacuum apparatus is described for the determination of oxygen in 3 to 5 mg of organic substance. The oxygen of the substance is converted to carbon monoxide by ignition in a bomb at 1050 to 1055° C. Corrections are calculated from thermodynamic data for the amounts of water and carbon dioxide not reacting at the ignition temperature.
THE DEPARTMENT OF ENERGY HIGH ENERGY PHYSICS PROGRAM

This paper describes the high-energy-physics program at the US Department of Energy. The mission and goals of the program are described along with the breadth of the overall program. Information on recommendations from community-based panels and committees is provided. Finally, details about the main astrophysics and cosmology projects are given.
Finding an Educational Perspective for Object-Oriented Development

The object‐oriented model has become exceedingly attractive as the best answer to the increasingly complex needs of the software development community. The initial boasts regarding quality, reuse, concurrency, and scalability are now being substantiated by documented software development experience. It is certainly appropriate, then, for educators who teach computer science (the current preparation for emerging software developers) to examine where object‐oriented development best fits into the computer science curriculum. How much of the paradigm‐‐language, analysis, design, management‐‐ought to be addressed? At what level in an undergraduate program are object‐oriented techniques appropriate? What are the risks involved? How is the object‐oriented approach effectively taught?.
Buckling of moderately thick, laminated cylindrical shells under torsion

The problem of instability of laminated, circular cylindrical shells under the action of torsional loads is investigated. The analysis is based on higher order shear deformation theory where the effect of transverse shear is taken under consideration. The buckling is elastic for moderately thick composite shells, and the geometry is assumed to be free of initial geometric imperfections. The equilibrium equations and the related boundary conditions were derived by variational methods and the buckling equations through the perturbation technique. Three theories (higher order, first order, and classical) are compared to determine their range of applicability in predicting critical conditions for moderately thick, torsionally loaded, cylindrical shells. The effects on the buckling load of stacking sequence, radius-to-thickness ratios, and length-to-radius ratios is assessed. The numerical results are presented, for a typical graphite/epoxy material, in tabular and graphical forms.
Gap-definable counting classes

The function class #P lacks an important closure property: it is not closed under subtraction. To remedy this problem, we introduce the function class GapP as a natural alternative to #P. GapP is the closure of #P under subtraction and has all the other useful closure properties of #P as well. We show that most previously studied counting classes, including PP, C"=P, and Mod"kP, are ''gap-definable,'' i.e., definable using the values of GapP functions alone. We show that there is a smallest gap-definable class, SPP, which is still large enough to contain Few. We also show that SPP consists of exactly those languages low for GapP, and thus SPP languages are low for any gap-definable class. These results unify and improve earlier disparate results of J. Cai and L. Hemachandra (Math. Systems Theory23, No. 2 (1990), 95-106) and J. Kobler et al. (J. Comput. System Sci.44, No. 2 (1992), 272-286). We show further that any countable collection of languages is contained in a unique minimum gap-definable class, which implies that the gap-definable classes form a lattice under inclusion. Subtraction seems necessary for this result, since nothing similar is known for the #P-definable classes.
Optically coupled high-voltage isolation amplifier.

A common and persistent problem in modern instrumentation is the observation and recording of small signal waveforms that are removed from ground by very high voltages. Examples of this are the instrumentation of neutral particle injectors used in controlled thermonuclear research and the construction of safety breaks for air core toroidal devices. To overcome this problem a very high voltage isolation amplifier was designed. It employs analog‐to‐digital conversion with serial data transmission on a fiber optic cable.
Growth of internal delaminations under cyclic compression in composite plates

Abstract The growth of internal delaminations in composite plates subjected to cyclic compression is investigated. Due to the compressive loading, these structures undergo repeated buckling-unloading of the delaminated layer with a resulting reduction of the interlayer resistance. An important characteristic of the problem is that the state of stress near the delamination tip is of mixed mode, I and II. Equations describing the growth of the delaminations under cyclic loads are obtained on the basis of a combined delamination buckling-post-buckling and fracture mechanics model. The latter is based on a mode-dependent critical fracture energy concept and is expressed in terms of the spread in the energy release rate in the pre- and post-buckling state. It is shown that such a model allows for the accumulation of microdamage at the delamination front. The growth laws developed in this manner are integrated numerically, in order to produce the delamination growth vs number of cycles curves. Furthermore, the investigation includes the possibility of unstable delamination growth. The study does not impose any restrictive assumptions regarding the delamination thickness and plate length (as opposed to the usual thin film assumptions). The results show that for a given value of delamination thickness h, the fatigue delamination growth is strongly affected by the relative location of the delamination through the plate thickness T, the fatigue growth being slower for a smaller value of h T (delaminations located closer to the surface). These theoretical predictions are confirmed by experimental results that are obtained for the growth of delaminations in graphite-epoxy unidirectional specimens under cyclic constant amplitude compressive loading. The test data, which were obtained for several different locations of the delamination through the thickness (hence different degrees of mode mixity), and different applied maximum compressive displacement, seem to be well-correlated with the theory.
Chemoselective Dieckmann-like condensations using N-methoxy-N-methylamides

Abstract The use of N-methoxy-N-methylamide as a chemoselective group in Dieckmann-like condensation is described. The chemoselectivity in these cyclizations is dependent on the counterion of the base employed.
Developmental Resting State Functional Connectivity for Clinicians

Resting state functional magnetic imaging (fMRI) is a novel means to examine functional brain networks. It allows investigators to identify functional networks defined by distinct, spontaneous signal fluctuations. Resting state functional connectivity (RSFC) studies examining child and adolescent psychiatric disorders are being published with increasing frequency, despite concerns about the impact of motion on findings. Here we review important RSFC findings on typical brain development and recent publications on child and adolescent psychiatric disorders. We close with a summary of the major findings and current strengths and limitations of RSFC studies.
Far-Infrared Transmittance and Reflectance of YBa2Cu3O7-δ Films on Si Substrates

The transmittance and reflectance of superconductive YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) thin films deposited on Si substrates have been measured in the far-infrared frequency region from 10 to 100 cm{sup {minus}1} (wavelength from 1,000 to 100 {micro}m) at temperatures between 10 and 300 K. The effects of interference, optical resonance, and antireflection on the radiative properties of high-temperature superconducting (HTSC) films are observed and quantitatively analyzed. Furthermore, the authors have measured the reflectance of the HTSC film-substrate composites for radiation incident on the substrate side (backside reflectance) for the first time. The backside reflectance increases significantly from the normal state to the superconducting state at certain frequencies; this experimentally demonstrates that HTSC films can be used to build far-infrared intensity modulators. The complex refractive index of the YBCO films is determined from the measured transmittance using the Drude model in the normal state and a two-fluid model in the superconducting state. The complex refractive index obtained from this study is useful for various applications of YBCO films, including radiation modulators, detectors, and Fabry-Perot resonators.
Time-dependent nucleation theory and the formation of interstellar grains

The theory of homogeneous nucleation is discussed and applied to the formation of interstellar grains. Special attention is given to the thermodynamics of very small clusters (N≈10); it is found that, at least for carbon and metals, the free energies ofN-mers may be conveniently expressed in terms of a parameter θ N which is nearly independent ofN. Estimates of θ N from the Lothe-Pound theory disagree with the experimental observations forN<10; it is preferable to simply approximate θ N ≈1/2θ∞ (θ∞ is known from bulk properties). The kinetic process of nucleation and cluster growth is essentially just a function of two dimensionless parameters; θ/T and η. The domain in which nucleation theory should be valid is delineated. Approximate formulae are given for the critical supercooling, the critical cluster size, and the mean final cluster size; more accurate numerical results are presented graphically. Nucleation of grains in planetary nebulae, novae, and red giant outflows is discussed. The origin of the Pt-rich nuggets found in the Allende meteorite is considered; it is shown that the nuggets could have been formed by homogeneous nucleation in the primordial solar nebula, whereas they couldnot have formed in a supernova explosion.
Global isostatic geoid anomalies for plate and boundary layer models of the lithosphere

Isostatic geoid anomalies are usually interpreted using a flat-earth, one-dimensional idealization. Isostatic anomalies on the spherical, self-gravitating earth differ from this idealization because: (1) degree one terms in the spherical harmonic expansion vanish; (2) each term in the spherical harmonic expansion is multiplied by (l + 2)/(l + 0.5) relative to the flat-earth case; (3) mass in cones rather than straight-sided columns is constant; and (4) further deformation of the earth is induced by the gravitational attraction of the deformation caused by the isostatic potential anomaly. When the effect of each of these is quantified, the second, third, and fourth nearly cancel, leaving the degree one, “over the horizon” effect providing the most important difference. Calculations of model isostatic geoid anomalies for the spherical analogues (developed here) of the plate and boundary layer thermal models show that this effect can bias estimates of geoid slopes by over 20%, although the effect is usually less than 5%. The geoid anomalies for these two models are quite different over old ocean basins, but they are unlikely to be distinguishable on the basis of global geoid observations owing to the presence of other larger perturbations in the geoid. Stripping the effects of plate aging and a hypothetical uniform, 35 km thick, isostatically-compensated continental crust from the observed geoid emphasizes that the largest-amplitude geoid anomaly is the geoid low of almost 120 m over West Antarctica. This anomaly is a factor of two greater in amplitude than the low of 60 m over Sri Lanka.
A Technique for Designing Dyadic Controllers

A new technique for designing dyadic controllers is established. By the use of the recently established matrix partial fraction expansion formula, the dyadic transformation matrices are naturally formed. A direct interpretation of the parameters of the dyadic transformation matrices via the residue matrices becomes possible.
European Organization for Research and Treatment of Cancer and Groupe d'Etude des Lymphomes de l'Adulte very favorable and favorable, lymphocyte‐predominant Hodgkin disease

BACKGROUND Lymphocyte-predominant Hodgkin disease (LPHD) is rare and has a natural history different from that of classic Hodgkin disease. There is little information in the literature regarding the role of chemotherapy in patients with early-stage LPHD. The objective of this study was to examine recurrence free survival (RFS), overall survival (OS), and patterns of first recurrence in patients with LPHD who were treated with radiotherapy alone or with chemotherapy followed by radiotherapy. METHODS From 1963 to 1996, 48 consecutive patients ages 16–49 years (median, 28 years) with Ann Arbor Stage I (n = 30 patients) or Stage II (n = 18 patients), very favorable (VF; n = 5 patients) or favorable (F; n = 43 patients) LPHD, according to the European Organization for Research and Treatment of Cancer and Groupe d'Etude des Lymphomes de l'Adulte (EORTC-GELA) criteria, received radiotherapy alone (n = 37 patients) or received chemotherapy followed by radiotherapy (n = 11 patients). The percentages of patients with VF disease (11% vs. 9% in the radiotherapy group vs. the chemotherapy plus radiotherapy group, respectively) or F disease (89% vs. 91%, respectively) within the two treatment groups were similar (P = 1.00). A median of three cycles of chemotherapy with mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) or with mitoxantrone, vincristine, vinblastine, and prednisone (NOVP) was given initially to six patients and five patients, respectively. A median total radiotherapy dose of 40 grays (Gy) given in daily fractions of 2.0 Gy was delivered to both treatment groups. RESULTS The median follow-up was 9.3 years, and 98% of patients were observed for ≥ 3.0 years. RFS was similar for patients who were treated with radiotherapy alone and patients who were treated with chemotherapy followed by radiotherapy (10-year survival rates: 77% and 68%, respectively; P = 0.89). The OS rate also was similar for the two groups (10-year survival rates: 90% and 100%, respectively; P = 0.43). MOPP or NOVP chemotherapy did not reduce the risk of recurrence outside of the radiotherapy fields. CONCLUSIONS MOPP or NOVP chemotherapy did not improve RFS or OS significantly in patients with VF or F LPHD, although the statistical power was limited. Ongoing clinical trials will help to clarify the role of a watch-and-wait strategy or systemic therapy, including anthracycline (epirubicin or doxorubicin), bleomycin, and vinblastine-based chemotherapy or antibody-based approaches, in the treatment of these patients. Cancer 2002;94:1731–8. © 2002 American Cancer Society. DOI 10.1002/cncr.10404
Reducing concurrent analysis under a context bound to sequential analysis

This paper addresses the analysis of concurrent programs with shared memory. Such an analysis is undecidable in the presence of multiple procedures. One approach used in recent work obtains decidability by providing only a partial guarantee of correctness: the approach bounds the number of context switches allowed in the concurrent program, and aims to prove safety, or find bugs, under the given bound. In this paper, we show how to obtain simple and efficient algorithms for the analysis of concurrent programs with a context bound. We give a general reduction from a concurrent program P, and a given context bound K, to a sequential program P s K such that the analysis of P s K can be used to prove properties about P. The reduction introduces symbolic constants and assume statements in P s K . Thus, any sequential analysis that can deal with these two additions can be extended to handle concurrent programs as well, under a context bound. We give instances of the reduction for common program models used in model checking, such as Boolean programs, pushdown systems (PDSs), and symbolic PDSs.
The avian and wildlife costs of fossil fuels and nuclear power

Environmentalists and environmental scientists have criticized wind energy in various forums for its negative impacts on wildlife, especially birds. This article highlights that nuclear power and f...
Edge magnetoplasmons in a partially screened two-dimensional electron gas on a helium surface

We report a study of edge magnetoplasmons in a partially screened system of electrons on a helium surface. We compare experimental results with theories of the frequency, damping, and penetration-depth dependence on magnetic field, temperature-dependent damping, and the dependence of the frequency on screening. We show explicitly the dependence of frequency on the edge density profile. The frequency and screening are in qualitative agreement with the theory of Fetter at small fields, and the frequencies agree with theory in the limit of zero magnetic field. The frequency and linewidths in intermediate and large fields exhibit the features of the qualitative predictions of Volkov and Mikhailov, but differ numerically. The dependence of frequency on the density profile is stronger than predicted by these authors, and the penetration-depth variation with field confirms their predictions for small fields.
Scaling for vibrational modes of fractals tethered at the boundaries

Abstract Using a mapping between a scalar elastic network tethered at its boundaries and a diffusion problem with permanent traps, we study various vibrational properties of progressively tethered disordered fractals. Different scaling forms are proposed for different types of boundary tethering and numerical investigation of the scaling is performed by the approximate diagonalization of the corresponding large, sparse transition probability matrices. Rather different localization behaviors are found for the leading modes depending on the type of tethering. For example, while the largest nontrivial eigenvalue for the tethering of the hull appears to scale by a power law of the cluster size S in an essentially same manner as the untethered case except for the amplitude which depends on the number of tethered sites, the corresponding quantity for the all-boundary tethering seems to scale logarithmically with S.
Satellite characterization of urban aerosols: Importance of including hygroscopicity and mixing state in the retrieval algorithms

[1] This model study examines the sensitivity of the calculated optical properties of urban aerosols to (1) hygroscopicity and (2) internal or external mixing state, and it further investigates the associated implications for the accuracy of satellite retrievals of aerosol optical thickness (t) and aerosol effective radius (reff). State-of-the-art retrieval algorithms widely omit variable hygroscopicity and mixing state. For the study described herein, the modeled urban aerosols are composed of water-soluble sulfates and water-insoluble black carbon (BC) in the fine mode and of water-insoluble compounds in the coarse mode. The calculations show that external compared to internal mixing of black carbon and sulfate not only significantly affects the single-scattering albedo but also alters the diagnostic relationship of the Angstrom exponent (a) to the aerosol effective radius. The implication is that over a dark surface of visible reflectance less than 0.1, satellite retrievals of urban aerosols having a BC/sulfate mass ratio of 5% can differ in t and reff by as much as 60% and 0.2 mm, respectively, depending upon the retrieval algorithm’s assumptions regarding hygroscopicity and mixing state. For surface reflectances greater than 0.1 or BC/sulfate mass ratios larger than 5%, the retrieval bias, including the possibility of unphysical retrievals, increases further. The calculations also show that hygroscopic growth at elevated relative humidity increases the single-scattering albedo of urban aerosols, decreases their backscattering, and as a consequence reduces the influence of mixing state on t and reff. These results suggest that current operational retrieval algorithms lead to a possibly systematic underestimate of aerosol optical thickness when ambient BC/sulfate aerosols are internally mixed at mass ratios greater than 3%. This study’s recommendation is that aerosol retrieval algorithms, when applied to urban aerosols, incorporate in situ knowledge of relative humidity, mixing state, and BC/sulfate mass ratios, either from ground-based measurements or by auxiliary use of chemical transport models.
Certain novel ribofuranosyl phosphates derived from 5-phospho-α-D-ribofuranosyl-1-pyrophosphate: synthesis, structure, and alkaline hydrolytic reactivities

On fait reagir le dicyclohexyl carbodiimide sur le O-phosphono-5 ribofuranosyle diphosphate pour obtenir le O-phosphono-5 ribofuranosyle phosphate-1,2. Une hydrolyse basique fournit les di-O-phosphono-2,5 ribofuranose et O-phosphono-5 ribofuranosyle phosphate
Properties of Large Multispot Ultrasonically Welded Joints

Using ultrasonic spotwelds, two series of overlap joints were prepared with aluminum alloys and tested in tension. In the first series between 4x12x0.063 in.-thick panels, it is shown that on a one-for-one basis ultrasonic welds produce joints superior to those made with Vi-in. steel fasteners. In the second series on 7075T6 and 2024-T3 alclad sheets 12 x 30 x 0.063 in. thick, joints were made with different numbers and arrays of spots. Joints based on row separations of 2 in. and pitches on the order of /4 in. are shown to be optimum and able to develop sheet stresses in excess of the yield strengths at failure. At pitch distances greater than A in., the higher individual spot loads can lead to shear and nugget failures as well as lower sheet stresses at failure. With a more dense population than at optimum pitch, there is a distinct reduction of sheet stress at failure. This is due, apparently, to restricted yield strain redistributions along the edges of the close packed rows of spots.
Double differential space-time block coding for time-selective fading channels

Most existing space-time coding schemes assume time-invariant fading channels and offer antenna diversity gains relying on accurate channel estimates at the receiver. Other single differential space-time block coding schemes forego channel estimation but are less effective in rapidly fading environments. Based on a diagonal unitary matrix group, a novel double differential space-time block coding approach is derived in this paper for time-selective fading channels. Without estimating the channels at the receiver, information symbols are recovered with antenna diversity gains regardless of frequency offsets. The resulting transceiver has very low complexity and is applicable to an arbitrary number of transmit and receive antennas. Approximately optimal space-time codes are also designed to minimize bit error rate. System performance is evaluated both analytically and with simulations.
Extended Strömgren Photoelectric Photometry in NGC 752

Photoelectric photometry on the extended Stromgren system (uvbyCa) is presented for 7 giants and 21 main-sequence stars in the old open cluster NGC 752. Analysis of the hk data for the turnoff stars yields a new determination of the cluster mean metallicity. From 10 single-star members, [Fe,H] = -0.06 ± 0.03, where the error quoted is the standard error of the mean and the Hyades abundance is set at [Fe,H] = +0.12. This result is unchanged if all 20 stars within the limits of the hk metallicity calibration are included. The derived [Fe/H] is in excellent agreement with past estimates, using properly zeroed m1 data, transformed moderate-dispersion spectroscopy, and recent high-dispersion spectroscopy.
Do fiduciary duties matter

Purpose – The purpose of this paper is to explore whether fiduciary duties impact the behavior of firm insiders. Trust law imposes stricter fiduciary obligations on insiders than corporate law does. This paper seeks to examine whether the difference in fiduciary duties impacts agency conflict, performance, and/or risk taking.Design/methodology/approach – The paper takes an empirical approach to answering the question by comparing mutual funds organized as trusts and as corporations. The existence of these two types of organizations within the same industry offers a unique laboratory for the study of the effects of fiduciary duties.Findings – Mutual funds organized in trust form charge significantly lower fees and take on less risk than equivalent mutual funds organized in corporate form. Evidence also suggests that the trusts tend to under‐perform their corporate counterparts, even after adjusting for differences in risk.Originality/value – Much of the existing literature on firm governance and investor p...
Coloring Kk-free intersection graphs of geometric objects in the plane

The intersection graph of a collection C of sets is the graph on the vertex set C, in which C"1,C"2@?C are joined by an edge if and only if C"1@?C"2 0@?. Erdos conjectured that the chromatic number of triangle-free intersection graphs of n segments in the plane is bounded from above by a constant. Here we show that it is bounded by a polylogarithmic function of n, which is the first nontrivial bound for this problem. More generally, we prove that for any t and k, the chromatic number of every K"k-free intersection graph of n curves in the plane, every pair of which have at most t points in common, is at most (c"tlognlogk)^c^l^o^g^k, where c is an absolute constant and c"t only depends on t. We establish analogous results for intersection graphs of convex sets, x-monotone curves, semialgebraic sets of constant description complexity, and sets that can be obtained as the union of a bounded number of sets homeomorphic to a disk. Using a mix of results on partially ordered sets and planar separators, for large k we improve the best known upper bound on the number of edges of a k-quasi-planar topological graph with n vertices, that is, a graph drawn in the plane with curvilinear edges, no k of which are pairwise crossing. As another application, we show that for every @e>0 and for every positive integer t, there exist @d>0 and a positive integer n"0 such that every topological graph with n>=n"0 vertices, at least n^1^+^@e edges, and no pair of edges intersecting in more than t points, has at least n^@d pairwise intersecting edges.
Dynamic dispatching in job class scheduled systems

Many different approaches have been attempted to the problem of controlling the processing of a multiprogramming computer system so as to improve performance. In Reference 1, Bowdon, et al. simulate an IBM 360/75 under OS with HASP and adjust job initiation priority based on estimates of processing time to effect a shortest-processing-time discipline. Their simulation demonstrates a dramatic increase in thruput and decrease in turnaround as a result of this job scheduling modification.
Asymptotic Analysis of MAP Estimation via the Replica Method and Applications to Compressed Sensing

The replica method is a nonrigorous but well-known technique from statistical physics used in the asymptotic analysis of large, random, nonlinear problems. This paper applies the replica method, under the assumption of replica symmetry, to study estimators that are maximum a posteriori (MAP) under a postulated prior distribution. It is shown that with random linear measurements and Gaussian noise, the replica-symmetric prediction of the asymptotic behavior of the postulated MAP estimate of an -dimensional vector “decouples” as scalar postulated MAP estimators. The result is based on applying a hardening argument to the replica analysis of postulated posterior mean estimators of Tanaka and of Guo and Verdu. The replica-symmetric postulated MAP analysis can be readily applied to many estimators used in compressed sensing, including basis pursuit, least absolute shrinkage and selection operator (LASSO), linear estimation with thresholding, and zero norm-regularized estimation. In the case of LASSO estimation, the scalar estimator reduces to a soft-thresholding operator, and for zero norm-regularized estimation, it reduces to a hard threshold. Among other benefits, the replica method provides a computationally tractable method for precisely predicting various performance metrics including mean-squared error and sparsity pattern recovery probability.
Some critical episodes in the progress of medical innovation: An Anglo-American perspective

Abstract The central concern of this paper is to show that medical innovations have depended heavily on breaking down barriers that have long prevailed in the academic world, in the form of disciplinary boundaries that have coalesced into separate departments; to be specific, some of the biggest breakthroughs for the Life Sciences have come from the realm of the Physical Sciences. The present study is confined mainly to molecular biology and to diagnostic technologies (as well as to the therapeutic technologies that have frequently flowed from them); both owed a great deal to institutional innovations that emerged in the Anglo-American medical research world. Opportunities for transfers of instrumentation and techniques across disciplinary boundaries have been considerably strengthened as medical schools have been located, geographically and organizationally, closer to the universities. The American Medical Centers and the Stanford Program provide many examples. These achieved more than counterparts in the UK like the Cavendish Laboratories at Cambridge, which had pioneered in such fields.
BPS saturated dyonic black holes of N = 8 supergravity vacua

We summarize the results for four-dimensional Bogomol'nyi-Prasad-Sommerfield (BPS) saturated dyonic black hole solutions arising in the Kaluza-Klein sector and the three-form field sector of the eleven-dimensional super-gravity on a seven-torus. These black hole solutions break ¾ of N = 8 supersymmetry, fill out the multipletes of U-duality group, and the two classes of solutions are related to each other by a discrete symmetry transformation in E7. Using the field redefinitions of the corresponding effective actions, we present these solutions in terms of fields describing classes of dyonic black holes carrying charges of U(1) gauge fields in Neveu-Schwarz-NeveuSchwarz and/or Ramond-Ramond sector(s) of the type-IIA superstring on a six-torus. We also summarize the dependence of their ADM masses on the asymptotic values of scalar fields, parameterizing the toroidal moduli space and the string coupling constant.
Why are ethnically divided countries poor

Abstract Ethnic divisions are associated with poor economic performance. This paper develops a model of ethnic conflict and finds that it is a significant source of poverty. Ethnic divisions lead the government to make ethnic transfers, which distort investment decisions, and lead to civil war because groups fight for control of the government. The simulated model generates the income gap between countries with and without ethnic divisions. Redistribution is the most important source of poverty. War costs cause less than a quarter of the reduction in income and divided countries are poorer even if they do not fight a war.
Flipping the classroom and instructional technology integration in a college-level information systems spreadsheet course

The purpose of this research was to explore how technology can be used to teach technological skills and to determine what benefit flipping the classroom might have for students taking an introductory-level college course on spreadsheets in terms of student achievement and satisfaction with the class. A pretest posttest quasi-experimental mixed methods design was utilized to determine any differences in student achievement that might be associated with the instructional approach being used. In addition, the scalability of each approach was evaluated along with students’ perceptions of these approaches to determine the affect each intervention might have on a student’s motivation to learn. The simulation-based instruction tested in this study was found to be an extremely scalable solution but less effective than the regular classroom and flipped classroom approaches in terms of student learning. While students did demonstrate learning gains, the process focus of the simulation’s instruction and assessments frustrated students and decreased their motivation to learn. Students’ attitudes towards the topic, their willingness to refer the course to others, and the likelihood that they would take another course like this were considerably lower than those of students in the flipped or regular classroom situations. The results of this study support the conclusion that a technology enhanced flipped classroom was both effective and scalable; it better facilitated learning than the simulation-based training and students found this approach to be more motivating in that it allowed for greater differentiation of instruction.
A Catalog of Diffuse Interstellar Bands in the Spectrum of HD 204827

Echelle spectra of the double-lined spectroscopic binary HD 204827 were obtained on five nights, at a resolving power R = 38,000 and with a S/N = 750 near 6000 A in the final, combined spectrum. The stars show E(B − V) = 1.11 and spectral types near O9.5 V and B0.5 III. A catalog is presented of 380 diffuse interstellar bands (DIBs) measured between 3900 and 8100 A in the stars' spectrum. The central wavelengths, the widths (FWHM), and the equivalent widths of nearly all of the bands are tabulated, along with the minimum uncertainties in the latter. The reliable removal of very weak stellar lines from the catalog, and of some stellar lines from the less severe blends with DIBs, is made generally easy by the highly variable radial velocities of both stars. The principal result of this investigation is that the great majority of the bands in the catalog are very weak and relatively narrow. Typical equivalent widths amount to a few mA, and the bandwidths (FWHM) are most often near 0.55 A. Therefore, most of these DIBs can be detected only in spectra obtained at a resolving power and a S/N at least comparable to those used here. In addition, the anomalous interstellar reddening and the very high value of the ratio N(C2)/E(B − V) seen toward HD 204827 indicate that the physical conditions in one or more of the several interstellar clouds seen in this direction differ significantly from those found toward the prototypical DIB target HD 183143, for example. Probably primarily for these reasons, 113 of the 380 bands (30%) were not detected in four previous modern surveys of the DIBs seen in the spectra of stars other than HD 204827. No preferred wavenumber spacings among the 380 bands are reliably identified which could provide clues to the identities of the large molecules thought to cause the DIBs.
Evaluating trade reform with many consumers

In this paper we look at the welfare effects of trade reform in the many-consumers case. We show that Pareto-improving reforms with lump-sum taxation or with non-lump-sum taxation are possible in the small country case if sufficient conditions for welfare to rise in
Energetics of Pt adsorption on Pt(111).

First-principles local-density-functional (FP-LDF) and embedded-atom-method (EAM) total energies, for a single Pt atom adsorbed on Pt(111), are compared to each other and to field-ion-microscope (FIM) observations. Our EAM calculations predict a small barrier to diffusion and only a slight energy difference between adsorption in the fcc and hcp threefold hollows (both smaller than 1 meV). They correspond poorly to the results of the FP-LDF calculations, which imply a diffusion barrier of 0.38 eV for passage over a bridge, and a preference of 0.18 eV for the fcc against the hcp site. FIM measurements yield a diffusion barrier of (0.25\ifmmode\pm\else\textpm\fi{}0.02) eV, and imply that binding in the fcc site is preferred.
A perturbative SU(3) Casson invariant

A perturbative SU(3) Casson invariant \( \Lambda_{SU(3)}(X) \) for integral homology 3-sphere is defined. Besides being fully perturbative, it has the nice properties: (1) \( 4\cdot \Lambda_{SU(3)} \) is an integer. (2) It is preserved under orientation change. (3) A connect sum formula. Explicit calculations of the invariant for 1/k surgery of (2, q) torus knot are presented and compared with Boden-Herald‚s different SU(3) generalization of Casson‚s invariant. For those cases computed, the invariant defined here is a quadratic polynomial in k for k > 0 and a different quadratic polynomial for k < 0.
Optimal Consumption Choices for a ‘Large’ Investor

Abstract This paper examines the optimal consumption and investment problem for a ‘large’ investor, whose portfolio choices affect the instantaneous expected returns on the traded assets. Alternatively, our analysis can be interpreted in terms of an optimal growth problem with nonlinear technologies. Existence of optimal policies is established using martingale and duality techniques under general assumptions on the securities' price process and the investor's preferences. As an illustration of our characterization result, explicit solutions are provided for specific examples involving an agent with logarithmic utilities and a generalized two-factor version of the CCAPM is derived. The analogy of the consumption problem examined in this paper to the consumption problem with constraints on the portfolio choices is emphasized.
Measures of agreement between computation and experiment: validation metrics

With the increasing role of computational modeling in engineering design, performance estimation, and safety assessment, improved methods are needed for comparing computational results and experimental measurements. Traditional methods of graphically comparing computational and experimental results, though valuable, are essentially qualitative. Computable measures are needed that can quantitatively compare computational and experimental results over a range of input, or control, variables to sharpen assessment of computational accuracy. This type of measure has been recently referred to as a validation metric. We discuss various features that we believe should be incorporated in a validation metric, as well as features that we believe should be excluded. We develop a new validation metric that is based on the statistical concept of confidence intervals. Using this fundamental concept, we construct two specific metrics: one that requires interpolation of experimental data and one that requires regression (curve fitting) of experimental data. We apply the metrics to three example problems: thermal decomposition of a polyurethane foam, a turbulent buoyant plume of helium, and compressibility effects on the growth rate of a turbulent free-shear layer. We discuss how the present metrics are easily interpretable for assessing computational model accuracy, as well as the impact of experimental measurement uncertainty on the accuracy assessment.
Managing the Intangible Aspects of a Project: The Affect of Vision, Artifacts, and Leader Values on Project Spirit and Success in Technology-Driven Projects:

Successful projects are often characterized by a unique spirit. Phase one results, based on 193 employees partaking in 60 projects across organizations, support a model positing that leader building activities affect employees' emotions, attitudes, and behavioral norms that are focused on expected project outcomes, termed project spirit. Spirit affects employees' contextual performance behavior, which in turn affects success as proposed. Phase two cases, designed to ground these results in technology-driven project contexts, highlight the value of managing the project's intangible aspects captured by spirit. Quantitative and qualitative findings imply that leaders can be coached to execute behaviors that generate a project's spirit, which boosts contextual performance behavior and increases project success.