cssi/SciSciGPT-SciSciNet huggingface dataset:
Upper Bounds on Packing Density for Circular Cylinders with High Aspect Ratio

In the early 1990s, Bezdek and Kuperberg used a relatively simple argument to show a surprising result: The maximum packing density of circular cylinders of infinite length in $$\mathbb {R}^3$$ R 3 is exactly $$\pi /\sqrt{12}$$ ? / 12 , the planar packing density of the circle. This paper modifies their method to prove a bound on the packing density of finite length circular cylinders. In fact, the maximum packing density for unit radius cylinders of length $$t$$ t in $$\mathbb {R}^3$$ R 3 is bounded above by $$\pi /\sqrt{12} + 10/t$$ ? / 12 + 10 / t .
Relativity of Remembering: Why the Laws of Memory Vanished

For 120 years, cognitive psychologists have sought general laws of learning and memory. In this review I conclude that none has stood the test of time. No empirical law withstands manipulation across the four sets of factors that Jenkins (1979) identified as critical to memory experiments: types of subjects, kinds of events to be remembered, manipulation of encoding conditions, and variations in test conditions. Another factor affecting many phenomena is whether a manipulation of conditions occurs in randomized, within-subjects designs rather than between-subjects (or within-subject, blocked) designs. The fact that simple laws do not hold reveals the complex, interactive nature of memory phenomena. Nonetheless, the science of memory is robust, with most findings easily replicated under the same conditions as originally used, but when other variables are manipulated, effects may disappear or reverse. These same points are probably true of psychological research in most, if not all, domains.
Long pulse electron beams

Measurement of the parameters of a long-pulse beam is discussed. The Troll accelerator produces the beam, and a conditioning cell is used to adjust beam parameters. This system has typically been operated with the following output parameters: 2.5 MV, 1-2 kA, 0.5-1.0 mu s. >
A distributed evolutionary method to design scheduling policies for volunteer computing

Volunteer Computing (VC) is a paradigm that uses idle cycles from computing resources donated by volunteers and connected through the Internet to compute large-scale, loosely-coupled simulations. A big challenge in VC projects is the scheduling of work-units across heterogeneous, volatile, and error-prone computers. The design of effective scheduling policies for VC projects involves subjective and time-demanding tuning that is driven by the knowledge of the project designer. VC projects are in need of a faster and project-independent method to automate the scheduling design.To automatically generate a scheduling policy, we must explore the extremely large space of syntactically valid policies. Given the size of this search space, exhaustive search is not feasible. Thus in this paper we propose to solve the problem using an evolutionary method to automatically generate a set of scheduling policies that are project-independent, minimize errors, and maximize throughput in VC projects. Our method includes a genetic algorithm where the representation of individuals, the fitness function, and the genetic operators are specifically tailored to get effective policies in a short time. The effectiveness of our method is evaluated with SimBA, a Simulator of BOINC Applications. Contrary to manually-designed scheduling policies that often perform well only for the specific project they were designed for and require months of tuning, our resulting scheduling policies provide better overall throughput across the different VC projects considered in this work and were generated by our method in a time window of one week.
Form factor expansion of the row and diagonal correlation functions of the two-dimensional Ising model

We derive and prove exponential and form factor expansions of the row correlation function σ0,0 σ0,N and the diagonal correlation function σ0,0 σN,N of the two-dimensional Ising model.
Strategy-proofness and efficiency are incompatible in production economies

In a production economy where a single private good is produced via a non-linear concave technology, no direct mechanism satisfies strategy-proofness and efficiency if the preference domain contains the class of linear preferences.
Management Practices, Relational Contracts and the Decline of General Motors

Abstract General Motors was once regarded as the best-managed and most successful firm in the world. However, between 1980 and 2009, GM's US market share fell from 46 to 20 percent, and in 2009 the firm went bankrupt. We argue that the conventional explanation for this decline—namely high legacy labor and healthcare costs—is seriously incomplete, and that GM's share collapsed for many of the same reasons that many highly successful American firms of the 1960s were forced from the market, including a failure to understand the nature of the competition they faced and an inability to respond effectively once they did. We focus particularly on the problems GM encountered in developing the relational contracts essential to modern design and manufacturing, and we discuss a number of possible causes for these difficulties. We suggest that GM's experience may have important implications for our understanding of the role of management in the modern, knowledge-based firm and for the potential revival of manufacturi...
Fracture of Yttria‐Doped, Sintered Reaction‐Bonded Silicon Nitride

Flexural strength of an yttria-doped, slip-cast, sintered reaction-bonded silicon nitride was evaluated as a function of temperature (20° to 1400°C in air), applied stress, and time. Static oxidation at 700o to 1400°C was investigated in detail; in tests at 1000°C in air, the material showed anomalous weight gain. Flexural stress-rupture testing a 800° to 1200°C in air indicated that the material is susceptible to stress-enhanced oxidation and early failure. Fractographic evidence for time-dependent and -independent failures is presented.
Optically pure chiral sulfoxides using ephedrine as a chiral auxiliary

Abstract Optically pure chiral sulfoxides can be formed in good to excellent yields by sequential displacement reactions of organometallic reagents on the 1,2,3-oxathiazolidine-S-oxide formed from ephedrine and thionyl chloride, a modification of the Wudl and Lee procedure.
Does Local Business Ownership Insulate Cities from Economic Shocks

We assess a prominent argument for local economic policies that favor locally-owned businesses – namely, that locally-owned firms are more likely to internalize the costs to the community of decisions to reduce employment and hence help to insulate cities from adverse economic shocks. We test this argument by examining how establishment-level employment responses to economic shocks are affected by establishment ownership. We find evidence that some types of local ownership do insulate regions from economic shocks, although the clearest benefits do not come from small, independent businesses, but instead from corporate headquarters and, to a lesser extent, from small, locally-owned chains.
Radar Target Recognition

Radar target recognition technology has advanced remarkably as radar technology advances recently. The resolution and features of modern radar system provide enough information to recognize tactical targets. Different types of radar, such as synthetic aperture radar (SAR ), milimeter-wave (MMW ) real aperture radar (RAR ), and interferometric synthetic aperture radar (IFSAR ), have been explored for radar target recognition. Target recognition from radar signatures is challenging since the radar signature is very sensitive to changes in look angle. There have been different approaches utilizing unique characteristics of different radar types, and they are reviewed in this article. They are hierarchical modeling of MMW RAR radar signatures for noncoorpertative target recognition, fusion of IFSAR data Earth orbit data for discriminating targets of different heights, the neural network approach, spatial matched filter for SAR , and fusion of multiple sensors. Keywords: radar target recognition; sensor fusion; hierarchical modeling; neural network
Alexander Duality, Gropes and Link Homotopy

We prove a geometric renement of Alexander duality for certain 2{complexes, the so-called gropes, embedded into 4{space. This renement can be roughly formulated as saying that 4{dimensional Alexander duality preserves the disjoint Dwyer ltration. In addition, we give new proofs and extended versions of two lemmas of Freedman and Lin which are of central importance in the A-B{slice problem ,t he main open problem in the classication theory of topological 4{manifolds. Our methods are group theoretical, rather than using Massey products and Milnor {invariants as in the original proofs. AMS Classication numbers Primary: 55M05, 57M25 Secondary: 57M05, 57N13, 57N70
Curtius rearrangement and Wolff homologation of functionalized peroxides

The Curtius and Wolff rearrangements of peroxide-containing alkanoyl azides and diazoketones provide an efficient entry to peroxy-substituted amines, isocyanates, carbamates, and peroxyalkanoates.
New insights into catalytic CO oxidation on Pt-group metals at elevated pressures

Abstract Producing a definitive picture of the CO oxidation reaction (CO + O 2 → CO 2 ) on Pt-group metals (Rh, Pd, Pt, and Ru) across the ‘pressure gap’ has proved to be a challenging task. Surface-sensitive techniques amenable to high pressure environments (e.g. PM-IRAS) have sparked a renewed interest in this reaction under realistic pressures. Here, we review recent work in our laboratory examining CO oxidation kinetics on Pt-group single crystals using PM-IRAS, XPS, and mass spectrometry from low (10 −8 –10 −3 Torr) to high (1–10 2 Torr) pressures. These studies have shown that at both low and high pressures (a) Langmuir–Hinshelwood kinetics adequately describe CO oxidation kinetics on Pt-group metals (Pt, Pd, Rh) (i.e. there is no pressure gap) and (b) the most active surface is one with minimal CO coverage. Additionally, recent investigations of high pressure CO oxidation kinetics on SiO 2 film supported Rh particles prepared in situ are discussed.
Response of an Oscillating System to Harmonic Forces of Time-Varying Frequency

Exact solutions for the steady-state response of a viscously damped linear system to excitations of sinusoidally varying frequency are presented. The principal application of these solutions is the response of a flexible component to unbalanced rotating machinery with speed governed by a closed-loop controller. Both base motions and applied forces are of interest. Previous authors have analyzed the case of a linearly increasing or decreasing excitation frequency. In this paper, the linear-sweep case is examined as an introduction to the important aspects of the problem, and the time history is obtained by numerical integration. Then, exact steady-state solutions for the response to forces and base motions of sinusoidally varying frequency are derived, along with a compact representation of the root-mean-square response that does not require numerical integration of the equation of motion. It is shown that an undamped system can have unbounded steady-state response even if the instantaneous excitation frequency never approaches the undamped natural frequency. Studies are conducted to demonstrate the behavior of the response for dierent values of the system parameters. Finally, the rotating unbalance problem is addressed for cases when the rotational speed of the machinery varies with time, in particular to investigate whether such excitations may be approximated with a force input. It is shown that as long as the frequency changes on a much longer time scale than the period of the underlying oscillation, such an approximation introduces little error. This work has applications in both the analysis of vibrations in rotating machinery and in the planning of vibration testing. The analysis focuses on near-resonant response, which is of the most practical interest and moreover can permit an approximate single-modal-degree-of-freedom analysis even when the system of interest has multiple modes, provided they are suciently separated in frequency.
Algorithmic Meta-theorems for Restrictions of Treewidth

Possibly the most famous algorithmic meta-theorem is Courcelle’s theorem, which states that all MSO-expressible graph properties are decidable in linear time for graphs of bounded treewidth. Unfortunately, the running time’s dependence on the formula describing the problem is in general a tower of exponentials of unbounded height, and there exist lower bounds proving that this cannot be improved even if we restrict ourselves to deciding FO logic on trees. We investigate whether this parameter dependence can be improved by focusing on two proper subclasses of the class of bounded treewidth graphs: graphs of bounded vertex cover and graphs of bounded max-leaf number. We prove stronger algorithmic meta-theorems for these more restricted classes of graphs. More specifically, we show it is possible to decide any FO property in both of these classes with a singly exponential parameter dependence and that it is possible to decide MSO logic on graphs of bounded vertex cover with a doubly exponential parameter dependence. We also prove lower bound results which show that our upper bounds cannot be improved significantly, under widely believed complexity assumptions. Our work addresses an open problem posed by Michael Fellows.
HAT-P-7: A RETROGRADE OR POLAR ORBIT, AND A THIRD BODY

We show that the exoplanet HAT-P-7b has an extremely tilted orbit, with a true angle of at least 86° with respect to its parent star's equatorial plane, and a strong possibility of retrograde motion. We also report evidence for an additional planet or companion star. The evidence for the unparalleled orbit and the third body is based on precise observations of the star's apparent radial velocity (RV). The anomalous RV due to rotation (the Rossiter-McLaughlin effect) was found to be a blueshift during the first half of the transit and a redshift during the second half, an inversion of the usual pattern, implying that the angle between the sky-projected orbital and stellar angular momentum vectors is 182°.5 ± 9°.4. The third body is implicated by excess RV variation of the host star over 2 yr. Some possible explanations for the tilted orbit of HAT-P-7b are a close encounter with another planet, the Kozai effect, and resonant capture by an inward-migrating outer planet.
FINITE-SAMPLE PROPERTIES OF FORECASTS FROM THE STATIONARY FIRST-ORDER AUTOREGRESSIVE MODEL UNDER A GENERAL ERROR DISTRIBUTION

We study the properties of the multi-period-ahead least-squares forecast for the stationary AR(1) model under a general error distribution. We find that the forecast is unbiased up to O ( T −1 ), where T is the in-sample size, regardless of the error distribution and that the mean squared forecast error, up to O ( T −3/2 ), is robust against nonnormality. The author is grateful to the co-editor Paolo Paruolo and two anonymous referees for helpful comments. The author is solely responsible for any remaining errors.
Isothermal remanent magnetization of Greenland ice: Preliminary results

The magnetic mineral content of wind-transported dust should reflect atmospheric transport dynamics and conditions in its source areas, and could thus be used as an environmental proxy. To test the feasibility of determining the magnetic mineral content in polar ice, isothermal remanent magnetization (IRM) was measured on a small suite of Greenland ice samples of Holocene (interglacial) and Last Glacial Maximum (LGM) age. Although the extremely low dust concentrations limit weak field (susceptibility) measurements, all samples contained an easily measurable concentration of magnetic minerals that can be estimated using IRM intensity provided that special precautions are used. IRM experiments at liquid nitrogen temperatures indicate ice magnetic properties which are consistent with that expected from varying concentrations of magnetite or maghemite. Interestingly, the Holocene ice samples tend to have higher magnetic concentrations, despite having much lower total polar dust contents, than the few LGM ice samples tested thus far.
Model Reference Adaptive Control of Five-Phase IPM Motors Based on Neural Network

This paper presents a novel model reference adaptive control of five-phase interior-permanent-magnet (IPM) motor drives. The primary controller is designed based on an artificial neural network (ANN) to simulate the nonlinear characteristics of the system without knowledge of accurate motor models or parameters. The proposed motor drive decouples the torque and flux components of five-phase IPM motors by applying multiple-reference-frame transformation. Therefore, the motor can be easily driven below the rated speed with the maximum-torque-per-ampere operation or above the rated speed with the flux weakening operation. The ANN-based primary controller consists of a radial basis function network which is trained online to adapt system uncertainties. The complete IPM motor drive is simulated in Matlab/Simulink environment and implemented experimentally utilizing a dSPACE DS1104 controller board on a five-phase prototype IPM motor.
Field performance of a nephelometer in rural kitchens: effects of high humidity excursions and correlations to gravimetric analyses

Rural kitchens of solid-fuel burning households constitute the microenvironment responsible for the majority of human exposures to health-damaging air pollutants, particularly respirable particles and carbon monoxide. Portable nephelometers facilitate cheaper, more precise, time-resolved characterization of particles in rural homes than are attainable by gravitational methods alone. However, field performance of nephelometers must contend with aerosols that are highly variable in terms of chemical content, size, and relative humidity. Previous field validations of nephelometer performance in residential settings explore relatively low particle concentrations, with the vast majority of 24-h average gravitational PM2.5 concentrations falling below 40 microg/m3. We investigate relationships between 24-h gravitational particle measurements and nephelometric data logged by the personal DataRAM (pDR) in highly polluted rural Chinese kitchens, where gravitationally determined 24-h average respirable particle concentrations were as high as 700 microg/m3. We find that where relative humidity remained below 95%, nephelometric response was strongly linear despite complex mixtures of aerosols and variable ambient conditions. Where 95% relative humidity was exceeded for even a brief duration, nephelometrically determined 24-h mean particle concentrations were nonsystematically distorted relative to gravitational data, and neither concurrent relative humidity measurements nor use of robust statistical measures of central tendency offered means of correction. This nonsystematic distortion is particularly problematic for rural exposure assessment studies, which emphasize upper quantiles of time-resolved particle measurements within 24-h samples. Precise, accurate interpretation of nephelometrically resolved short-term particle concentrations requires calibration based on short-term gravitational sampling.
Applied computer science

It is a truism that we are in the throes of an information revolution of which one obvious manifestation is a very rapid growth in the number of users of computers and computer-like information processing systems.
Conflict, settlement, and the shadow of the future

Abstract We examine a conflictual setting in which adversaries cannot contract on an enforcement variable (arms) and where the future strategic positions of adversaries are very different when there is open conflict than when there is settlement. We show that, as the future becomes more important in this setting, open conflict becomes more likely than settlement. We demonstrate the theoretical robustness of this finding and test it in a laboratory experiment. As predicted, we find that subjects are more likely to engage in destructive conflict as the future becomes more important.
Deterministic Public-Key Encryption for Adaptively-Chosen Plaintext Distributions

Bellare, Boldyreva, and O’Neill (CRYPTO ’07) initiated the study of deterministic public-key encryption as an alternative in scenarios where randomized encryption has inherent drawbacks. The resulting line of research has so far guaranteed security only for adversarially-chosen plaintext distributions that are independent of the public key used by the scheme. In most scenarios, however, it is typically not realistic to assume that adversaries do not take the public key into account when attacking a scheme.
Some interesting things about polysiloxanes.

Poly(dimethylsiloxane) [−Si(CH3)2O−] is by far the most studied of the polysiloxanes and is known to exhibit some intriguing physical properties, in particular very high permeability to gases. Simulations are underway in an attempt to understand some of these peculiarities. In addition, other symmetrically substituted polysiloxanes exhibit mesophases that are not understood at all. In the case of cross-linked polysiloxanes, there have been many important developments, including (i) elastomers undergoing strain-induced crystallization through control of chain stiffness or stereochemical structure, (ii) model elastomers (including dangling-chain networks), (iii) possible thermoplastic elastomers, (iv) bimodal network chain-length distributions, and (v) cross linking in solution. Interesting elastomeric composites include those with (i) in-situ-generated ceramiclike particles, (ii) ellipsoidal fillers, (iii) claylike-layered fillers, (iv) polyhedral oligomeric silsesquioxane (POSS) particles, (v) porous fill...
Silver-catalyzed [2,3]-rearrangement of halonium ylides derived from allyl and propargyl halides and alkyl diazoacetates

A silver(I) complex derived from a polyfluorinated tris(pyrazolyl)borate effectively catalyzes carbene transfer to allylic and propargylic halides, leading to the formation of α-haloacetate derivatives.
Inhibition of serine proteases by functionalized sulfonamides coupled to the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold.

Abstract A challenge associated with drug design is the development of selective inhibitors of proteases (serine or cysteine) that exhibit the same primary substrate specificity, that is, show a preference for the same P 1 residue. While these proteases have similar active sites, nevertheless there are subtle differences in their S and S′ subsites which can be exploited. We describe herein for the first time the use of functionalized sulfonamides as a design and diversity element which, when coupled to the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold yields potent, time-dependent inhibitors of the serine proteases human leukocyte elastase (HLE), proteinase 3 (PR 3) and cathepsin G(Cat G). Our preliminary findings suggest that (a) appending to the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold recognition and diversity elements that interact with both the S and S′ subsites of a target protease may result in optimal enzyme selectivity and potency and, (b) functionalized sulfonamides constitute a powerful design and diversity element with low intrinsic chemical reactivity and potentially wide applicability.
POLITICAL ISSUES AND PARTY ALIGNMENTS: Assessing the Issue Evolution Perspective

▪ Abstract Although the study of realignment is an essential component of the rich and fruitful tradition of examining long-term partisan change, questions about the usefulness of the concept persist. We seek to redirect and reinvigorate the study of lasting political change by evaluating the critiques of classic realignment theory, examining the issue evolution perspective, and assessing whether the theory of issue evolution can be used to explain recent research on the relationship between political issues and partisan change. Our review of the theoretical and empirical literature investigating political issues and party alignments sheds light on both the utility of the issue evolution perspective and the conditions under which durable changes in party alignments are most likely to occur.
IR-Improved Operator Product Expansions in non-Abelian Gauge Theory

We present a formulation of the operator product expansion that is infrared finite to all orders in the attendant massless non-Abelian gauge theory coupling constant which we will oftentimes associate with the QCD theory. We actually have the QCD theory as our primary objective in view of the operation of the LHC at CERN. We make contact in this way with the recently introduced IR-improved DGLAP-CS theory and point-out phenomenological implications accordingly, with an eye toward the precision QCD theory for LHC physics.
Synthesis of site-directed chelating agents II: 2-formyl-3-hydroxy-4,5-bis (hydroxymethyl)pyridine thiosemicarbazone.

Abstract 2‐Formyl‐3‐hydroxy‐4,5‐bis(hydroxymethyl)pyridine thiosemicarbazone was synthesized in an attempt to direct the chelating potential of this agent to the active site of the zinc‐requiring enzyme pyridoxal phosphokinase. Evaluation of the anti‐neoplastic activity of this agent in the sarcoma 180 and L‐1210 leukemia systems in mice showed potent activity. The presence or absence of pyridoxine hydrochloride in the diet did not influence the degree of inhibition of the growth of sarcoma 180 ascites cells. In addition, 2‐formyl‐3‐hydroxy‐4,5‐bis(hydroxymethyl)pyridine thiosemicarbazone was inactive against a subline of sarcoma 180 resistant to 1‐formylisoquinoline thiosemicarbazone, suggesting that the former agent may have a biochemical mechanism of action similar to that of the latter. In keeping with this expectation, 2‐formyl‐3‐hydroxy‐4,5‐bis(hydroxymethyl)pyridine thiosemicarbazone inhibited the synthesis of DNA but not of RNA or protein in sarcoma 180 ascites cells in vitro .
Social Multipliers in Sexual Initiation Decisions Among U.S. High School Students

In this article, I use a national sample of high school students to test for several types of social influences on the decision to have sexual intercourse. I find evidence of endogenous social interactions (social multipliers), where the propensity of an individual choosing to have sex varies with the average behavior in his or her school. Additionally, the magnitude of the social multipliers and several other interesting risk factors differ by gender and by race. These findings might help explain the large variation in sexual initiation across schools in the United States. These results also add to the debate over school vouchers and ability grouping because social multipliers imply changes in school-wide rates of sexual behavior with moderate changes in school-body composition. In this way, school vouchers and ability grouping might exacerbate the situation of high rates of teenage pregnancy and out-of-wedlock births in some communities. To show the potential benefits and costs of public policies that cause students to change schools, I present the results of several simulation exercises that predict the school-level changes in rates of sexual initiation following changes in school composition.
Exploiting channel memory for joint estimation and scheduling in downlink networks

We address the problem of opportunistic multiuser scheduling in downlink networks with Markov-modeled outage channels. We consider the scenario in which the scheduler does not have full knowledge of the channel state information, but instead estimates the channel state information by exploiting the memory inherent in the Markov channels along with ARQ-styled feedback from the scheduled users. Opportunistic scheduling is optimized in two stages: (1) Channel estimation and rate adaptation to maximize the expected immediate rate of the scheduled user; (2) User scheduling, based on the optimized immediate rate, to maximize the overall long term sum-throughput of the downlink. The scheduling problem is a partially observable Markov decision process with the classic ‘exploitation vs exploration’ trade-off that is difficult to quantify. We therefore study the problem in the framework of Restless Multi-armed Bandit Processes (RMBP) and perform a Whittle's indexability analysis. Whittle's indexability is traditionally known to be hard to establish and the index policy derived based on Whittle's indexability is known to have optimality properties in various settings. We show that the problem of downlink scheduling under imperfect channel state information is Whittle indexable and derive the Whittle's index policy in closed form. Via extensive numerical experiments, we show that the index policy has near-optimal performance. Our work reveals that, under incomplete channel state information, exploiting channel memory for opportunistic scheduling can result in significant performance gains and that almost all of these gains can be realized using an easy-to-implement index policy.
Improving the scalability of parallel N-body applications with an event-driven constraint-based execution model

The scalability and efficiency of graph applications are significantly constrained by conventional systems and their supporting programming models. Technology trends such as multicore, manycore, and heterogeneous system architectures are introducing further challenges and possibilities for emerging application domains such as graph applications. This paper explores the parallel execution of graphs that are generated using the Barnes-Hut algorithm to exemplify dynamic workloads. The workloads are expressed using the semantics of an exascale computing execution model called ParalleX. For comparison, results using conventional execution model semantics are also presented. We find improved load balancing during runtime and automatic parallelism discovery by using the advanced semantics for exascale computing.
Tall, Grande, or Venti: Presidential Powers in the United States and Latin America

Comparative constitutional studies rank the US president as relatively weak and most Latin American presidents as strong. However, specialized studies suggest that US presidents have great abilities to implement their agendas. We argue that presidents with weak formal powers “reinforce” their ability to impose an agenda (scope), as well as their ability to make those decisions stick (force). These reinforced powers, however, have diminishing returns as formal powers rise. As a result, the sum of presidential powers ranges from high (the US) to very high (Latin America).
Wavelength considerations in soft x-ray projection lithography

The choice of the operational wavelength for a soft-x-ray projection lithography system affects a wide variety of system parameters such as optical design, sources, resists, and multilayer mirrors. Several system constraints limit the choice for the operational wavelength. In particular, optical imaging requirements place an upper limit and throughput issues place a lower limit on the wavelength selection. We have determined that there are several discrete wavelength regions between 10 and 25 nm that satisfy the system-imposed constraints of high resolution, large depth of focus, and high throughput.
Adjunctive Psychotherapy for Bipolar Disorder: State of the Evidence

Objective: Psychotherapy has long been recommended as adjunctive to pharmacotherapy for bipolar disorder, but it is unclear which interventions are effective for which patients, over what intervals, and for what domains of outcome. This article reviews randomized trials of adjunctive psychotherapy for bipolar disorder. Method: Eighteen trials of individual and group psychoeducation, systematic care, family therapy, interpersonal therapy, and cognitive-behavioral therapy are described. Relevant outcome variables include time to recovery, recurrence, duration of episodes, symptom severity, and psychosocial functioning. Results: The effects of the treatment modalities varied according to the clinical condition of patients at the time of random assignment and the polarity of symptoms at follow-up. Family therapy, interpersonal therapy, and systematic care appeared to be most effective in preventing recurrences when initiated after an acute episode, whereas cognitive-behavioral therapy and group psychoeducatio...
On BMS Invariance of Gravitational Scattering

BMS+ transformations act nontrivially on outgoing gravitational scattering data while preserving intrinsic structure at future null infinity ( $$ \mathrm{\mathcal{I}} $$ +). BMS− transformations similarly act on ingoing data at past null infinity ( $$ \mathrm{\mathcal{I}} $$ −). In this paper we apply — within a suitable finite neighborhood of the Minkowski vacuum — results of Christodoulou and Klainerman to link $$ \mathrm{\mathcal{I}} $$ + to $$ \mathrm{\mathcal{I}} $$ − and thereby identify “diagonal” elements BMS0 of BMS+ × BMS−. We argue that BMS0 is a nontrivial infinite-dimensional symmetry of both classical gravitational scattering and the quantum gravity $$ \mathcal{S} $$ -matrix. It implies the conservation of net accumulated energy flux at every angle on the conformal S 2 at $$ \mathrm{\mathcal{I}} $$ . The associated Ward identity is shown to relate S-matrix elements with and without soft gravitons. Finally, BMS0 is recast as a U(1) Kac-Moody symmetry and an expression for the Kac-Moody current is given in terms of a certain soft graviton operator on the boundary of $$ \mathrm{\mathcal{I}} $$ .
DieHarder: securing the heap

Heap-based attacks depend on a combination of memory management error and an exploitable memory allocator. Many allocators include ad hoc countermeasures against particular exploits but their effectiveness against future exploits has been uncertain. This paper presents the first formal treatment of the impact of allocator design on security. It analyzes a range of widely-deployed memory allocators, including those used by Windows, Linux, FreeBSD and OpenBSD, and shows that they remain vulnerable to attack. It them presents DieHarder, a new allocator whose design was guided by this analysis. DieHarder provides the highest degree of security from heap-based attacks of any practical allocator of which we are aware while imposing modest performance overhead. In particular, the Firefox web browser runs as fast with DieHarder as with the Linux allocator.
Income and the utilization of long-term care services: Evidence from the Social Security benefit notch

This paper estimates the impact of income on the long-term care utilization of elderly Americans using a natural experiment that led otherwise similar retirees to receive significantly different Social Security payments based on their year of birth. Using data from the 1993 and 1995 waves of the AHEAD, we estimate instrumental variables models and find that a positive permanent income shock lowers nursing home use but increases the utilization of paid home care services. We find some suggestive evidence that the effects are due to substitution of home care for nursing home utilization. The magnitude of these estimates suggests that moderate reductions in post-retirement income would significantly alter long-term utilization patterns among elderly individuals.
Robustness and U.S. Monetary Policy Experimentation

We study how a concern for robustness modifies a policy maker’s incentive to experiment. A policy maker has a prior over two submodels of inflationunemployment dynamics. One submodel implies an exploitable trade-off, the other does not. Bayes’ law gives the policy maker an incentive to experiment. The policy maker fears that both submodels and his prior probability distribution over them are misspecified. We compute decision rules that are robust to misspecifications of each submodel and of the prior distribution over submodels. We compare robust rules to ones that Cogley, Colacito, and Sargent (2007) computed assuming that the models and the prior distribution are correctly specified. We explain how the policy maker’s desires to protect against misspecifications of the submodels, on the one hand, and misspecifications of the prior over them, on the other, have different effects on the decision rule.
Color plane interpolation using alternating projections

Most commercial digital cameras have three types of color sensors (for red, green, and blue channels) that are placed on a detector surface according to a specific pattern. At the location of each pixel only one color sample is taken, and the values of the other colors must be interpolated using neighboring samples. This color plane interpolation is known as demosaicing; it is one of the important tasks in a digital camera pipeline. If demosaicing is not performed appropriately, images suffer from highly visible color artifacts. In this paper we present a new demosaicing technique that uses inter-channel correlation effectively in an alternating-projections scheme. We have compared this technique with various state-of-the-art demosaicing techniques, and it outperforms all of them, both visually and in terms of mean square error.
Strategic Militarization, Deterrence and Wars ∗

We study countries choosing armament levels and then whether or not to go to war. We show that if the costs of war are not overly high or low, then all equilibria must involve dove, hawk, and deterrent strategies and the probability of war is positive (but less than one) in any given period. Wars are between countries with differing armament levels and the frequency of wars is tempered by the presence of armament levels that are expressly chosen for their deterrent properties. As the probability of winning a war becomes more reactive to increased armament, the frequency of wars decreases. As it becomes increasingly possible to negotiate a credible settlement, the probability of peace increases, but the variance of armament levels increases and war becomes increasingly likely when negotiations break down.
Computation of Minimum-Volume Covering Ellipsoids

We present a practical algorithm for computing the minimum-volume n-dimensional ellipsoid that must contain m given points a1,',am â ân. This convex constrained problem arises in a variety of applied computational settings, particularly in data mining and robust statistics. Its structure makes it particularly amenable to solution by interior-point methods, and it has been the subject of much theoretical complexity analysis. Here we focus on computation. We present a combined interior-point and active-set method for solving this problem. Our computational results demonstrate that our method solves very large problem instances (m = 30,000 and n = 30) to a high degree of accuracy in under 30 seconds on a personal computer.
Computer abuse perpetrators and vulnerabilities of computer systems

Analysis of computer abuse experience is valuable in threat and risk studies performed to develop appropriate safeguards in computer use. A profile of computer abuse perpetrators has been developed on the basis of interviews with 17 offenders involved in a total of 15 cases. Common characteristics, occupations, and modus operandi are documented and analyzed. Computer systems' and user organizations' vulnerabilities that facilitated perpetrators' actions are also described, based on study of 375 reported cases of abuse. Eight main vulnerable functions and nine main vulnerable functional locations are identified and ranked by incidence of occurrence. Each vulnerability is described by examples in the form of brief case descriptions. Finally, priorities for safeguards are deduced from the results of the study.
Economic equality and victory in war: An empirical investigation

This paper tests a simple hypothesis: that given the occurrence of war between two countries, the country that is more egalitarian at the moment of military decision is likely to emerge the victor. First, we examine cases where comparative economic inequality can be measured directly, using the nearly comprehensive global datasets of the University of Texas Inequality Project for the years 1963–1999. Second, we examine cases where reasonable inferences about comparative economic inequality may be drawn by analogy to UTIP measurements or from other political and economic evidence, including both bi‐national wars and larger wars where there existed clear pair‐wise fronts. Third, we discuss selected cases where inferences may be drawn from literary or historical sources. We find, all in all, that the evidence for an egalitarian victory proposition is remarkably strong.
Partial Bi-Invariance of SE(3) Metrics

In a flurry of articles in the mid to late 1990s, various metrics for the group of rigid-body motions, SE(3), were introduced for measuring distance between any two reference frames or rigid-body motions. During this time it was shown that one can choose a smooth distance function that is invariant under either all left shifts or all right shifts, but not both. For example, if one defines the distance between two reference frames to be an appropriately weighted Frobenius norm of the difference of the corresponding homogeneous transformation matrices, this will be invariant under left shifts by arbitrary rigid-body motions. However, this is not the full picture — other invariance properties exist. Though the Frobenius norm is not invariant under right shifts by arbitrary rigid-body motions, for an appropriate weighting it is invariant under right shifts by pure rotations. This is also true for metrics based on the Lie-theoretic logarithm. This paper goes further to investigate the full invariance properties of distance functions on SE(3), clarifying the full subsets of motions under which both left and right invariance is possible.Copyright © 2014 by ASME
On the Precision Attainable with Various Floating-Point Number Systems

For scientific computations on a digital computer the set of real numbers is usually approximated by a finite set F of ``floating-point'' numbers. We compare the numerical accuracy possible with different choices of F having approximately the same range and requiring the same word length. In particular, we compare different choices of base (or radix) in the usual floating-point systems. The emphasis is on the choice of F, not on the details of the number representation or the arithmetic, but both rounded and truncated arithmetic are considered. Theoretical results are given, and some simulations of typical floating-point computations (forming sums, solving systems of linear equations, finding eigenvalues) are described. If the leading fraction bit of a normalized base-2 number is not stored explicitly (saving a bit), and the criterion is to minimize the mean square roundoff error, then base 2 is best. If unnormalized numbers are allowed, so the first bit must be stored explicitly, then base 4 (or sometimes base 8) is the best of the usual systems.
Global imbalances before and after the global crisis

This paper surveys the academic and policy debate on the roots of global imbalances, their role in the inception of the global crisis, and their prospects in its aftermath. The conventional view holds that global imbalances result primarily from unsustainably high demand for goods in the United States and other rich countries, and that their impending correction must involve major United States trade adjustment and dollar depreciation -- although recent literature argues that their extent may be dampened by financial adjustment effects. In contrast, an alternative view portrays global imbalances as the equilibrium result of asymmetries in world asset demand and supply. Absent changes in the deep determinants of these, global imbalances can persist. International capital flow patterns before and during the crisis lend support to the equilibrium view. The paper also examines different hypotheses proposed in the literature on the role of global imbalances in the generation and propagation of the financial crisis. On the whole, the evidence suggests that global imbalances were not among the major causes of the crisis. Lastly, the paper assesses alternative scenarios about the future of global imbalances, considering in particular their potential consequences for developing countries, and the policy measures that these might adopt to enhance their growth prospects in a changing global equilibrium.
3D whole-heart coronary MR angiography at 1.5T in healthy volunteers: comparison between unenhanced SSFP and Gd-enhanced FLASH sequences.

Results: The SSFP sequence rendered higher visibility coronary segments, higher image quality, as well as higher SNR and CNR than the Gd-enhanced FLASH technique at 1.5T (p < 0.05). The visibility of coronary segments, image quality, SNR and CNR in the ESN, MDN and MDW with SSFP sequence did not differ significantly. Conclusion: An SSFP sequence provides an excellent method for the 3D whole-heart coronary MRA at 1.5T. Contrast enhanced coronary MRA using the FLASH sequence does not help improve the visibility of coronary segments, image quality, SNR or CNR on the 3D whole-heart coronary MRA. Index terms: Cardiac magnetic resonance; Coronary artery imaging; Steady-state free precession; Fast low-angle shot; Contrast agent; 1.5T
σ-Chelation-directed C–H functionalizations using Pd(II) and Cu(II) catalysts: regioselectivity, stereoselectivity and catalytic turnover

Recent progress in σ-chelation directed C–H functionalization from the authors' group is described to illustrate the challenges and opportunities in the development of synthetically-useful catalytic reactions involving C–H activation as the key step. Emphasis is placed on strategies for developing catalysis under mild conditions and controlling regio- and stereoselectivity.
DETERMINING THE TOUGHNESS OF CERAMICS FROM VICKERS INDENTATIONS USING THE CRACK-OPENING DISPLACEMENTS: AN EXPERIMENTAL STUDY

Recently, a method for evaluating the fracture toughness of ceramics has been proposed based on the computed crack-opening displacements of cracks emanating from Vickers hardness indentations. In order to verify this method, experiments were carried out to determine the toughness of a commercial silicon carbide ceramic, Hexaloy SA, by measuring the crack-opening profiles of such Vickers indentation cracks. While the obtained toughness value of Ko = 2.3 MPavm was within 10% of that measured using conventional fracture toughness testing, the computed crack-opening profiles corresponding to this toughness displayed poor agreement with those measured experimentally, raising concerns about the suitability of this method for determining the toughness of ceramics. The effects of subsurface cracking and cracking during loading are considered as possible causes of such discrepancies, with the former based on evidence observed for secondary radial cracking which affected the crack opening profile and deduced toughness values.
Synthesis of ThCr2Si2-type arsenides from Bi flux

LaCo2As2 can be synthesized as pure crystalline material by annealing a mixture of elements in Bi flux. The reaction, however, is accompanied by the incorporation of a small quantity of Bi into the structure and the formation of vacancies in the Co sublattice, which lead to substantial changes in structural and magnetic properties of the material.