cssi/SciSciGPT-SciSciNet huggingface dataset:
NASA's telerobotics research program

In 1985, NASA instituted a research program in telerobotics to develop and provide the technology for applications of telerobotics to the United States space program. The authors describe the goals, organizing framework, and content of that endeavor. They review the actual tasks which comprise the content of the program which has evolved significantly in terms of its content, goals, and approach. The lessons learned in that time comprise the organizing framework of the current program. This organizing framework is described. >
Directional behavior of thermal emission from a rough lunar surface.

The directionality is studied of the infrared emission from the lunar surface. A rough surface is postulated where the roughness is characterized by a crater field on a plain surface. The contour of the craters is assumed to be spherical. This makes it possible to determine the thermal emission on the basis of the temperature distribution obtained analytically by Adorjan (1970). By integrating the radiosities of both the craters and plain surfaces over a control area, and for given solar elevation and observation angles, the brightness temperatures are determined. The obtained results are presented in diagrams and discussed.
A Divide-and-Conquer Solver for Kernel Support Vector Machines

The kernel support vector machine (SVM) is one of the most widely used classification methods; however, the amount of computation required becomes the bottleneck when facing millions of samples. In this paper, we propose and analyze a novel divide-and-conquer solver for kernel SVMs (DC-SVM). In the division step, we partition the kernel SVM problem into smaller subproblems by clustering the data, so that each subproblem can be solved independently and efficiently. We show theoretically that the support vectors identified by the subproblem solution are likely to be support vectors of the entire kernel SVM problem, provided that the problem is partitioned appropriately by kernel clustering. In the conquer step, the local solutions from the subproblems are used to initialize a global coordinate descent solver, which converges quickly as suggested by our analysis. By extending this idea, we develop a multilevel Divide-and-Conquer SVM algorithm with adaptive clustering and early prediction strategy, which outperforms state-of-the-art methods in terms of training speed, testing accuracy, and memory usage. As an example, on the covtype dataset with half-a-million samples, DC-SVM is 7 times faster than LIBSVM in obtaining the exact SVM solution (to within 10-6 relative error) which achieves 96.15% prediction accuracy. Moreover, with our proposed early prediction strategy, DC-SVM achieves about 96% accuracy in only 12 minutes, which is more than 100 times faster than LIBSVM.
Nontraded goods, nontraded factors, and international non-diversification

Abstract Can the presence of nontraded consumption goods or nontraded factors of production explain the high degree of “home bias” displayed by investor portfolios? We find that the answer is no, so long as individuals have access to free international trade in financial assets. In particular, it is never optimal to exhibit home bias with respect to domestic traded-good equities. By contrast, holdings of nontraded-good equities in an optimal portfolio will depend sensitively on the elasticity of substitution between traded and nontraded goods.
Supported molecular catalysts: metal complexes and clusters on oxides and zeolites

When metal complexes and clusters are bonded to oxide or zeolite supports, they may combine the technological advantages of solid catalysts (robustness for high-temperature operation, lack of corrosiveness, ease of separation from products) with the selectivity of soluble molecular catalysts. Supported mononuclear metal complexes are typically synthesized by the reaction of a mononuclear organometallic compound with oxygen atoms or OH groups of the support, giving structures shown by infrared, X-ray absorption, and NMR spectroscopies and density functional theory to be analogous to those of molecular species, but with the support playing the role of a multidentate ligand, bonding strongly to the metal and holding the groups apart from each other on the support surface. Some supported metal complexes have new and unexpected catalytic activities. Supported metal clusters are formed by adsorption or surface-mediated synthesis of metal carbonyl clusters, which under some conditions may be decarbonylated on the support with the metal frame remaining essentially intact. The decarbonylated clusters are bonded to the supports by metal–oxygen bonds similar to those characterizing supported metal complexes; even noble metals in clusters on supports at the metal–support interface are cationic, and the metal–oxygen distances are about 2.1–2.2 A, matching the distances in mononuclear metal complexes with metal–oxygen bonds. Metal clusters are preferentially bonded at defect sites on oxide surfaces. The catalytic activities of supported metal clusters of only a few atoms are distinct from those of bulk metals; the supports act as ligands affecting the catalysis.
SLIDING DISKS IN THE PLANE

Given a pair of start and target configurations, each consisting of n pairwise disjoint disks in the plane, what is the minimum number of moves that suffice for transforming the start configuration into the target configuration? In one move a disk slides in the plane without intersecting any other disk, so that its center moves along an arbitrary (open) continuous curve. We discuss efficient algorithms for this task and estimate their number of moves under different assumptions on disk radii. For example, with n congruent disks, moves always suffice for transforming the start configuration into the target configuration; on the other hand, moves are sometimes necessary.
Random pattern testability of delay faults

In a computer system, the maximum allowable propagation delay of the combinational logic networks between latches is equal to the interval between the system clocks. The objective of delay testing is to guarantee that the delay of the manufactured network falls within specifications. Here, the capability of random patterns to detect slow paths in combinational logic is analyzed. Formulas that relate the length of the test to the desired test quality are derived. >
Greenwash vs. Brownwash: Exaggeration and Undue Modesty in Corporate Sustainability Disclosure

Corporate greenwashing has accelerated in recent years, bringing in its wake growing skepticism about corporate green claims. Although a theory of the drivers and deterrents of greenwashing has begun to emerge, it is static in nature and does not incorporate the full range of ways in which firms can misrepresent their environmental performance. Our contribution is threefold. First, we extend the theory of organizational information disclosure to incorporate the possibility of undue modesty about a firm's environmental, social, and governance practices. Second, we hypothesize about the drivers of exaggeration and undue modesty based on which of a firm's stakeholders are salient at a given point in time; to do so, we place the firm within a dynamic context that has largely been missing in the prior literature. Third, we test our hypotheses using a data set that allows us to directly compare corporate green claims against actual performance. Results reveal that corporate output growth, deregulation, and low profits under deregulation significantly affect the choice between greenwashing and brownwashing. The effects of growth and profits are mitigated by external scrutiny.
Care-related quality of life in old age

Promoting quality of life is a central theme in recent ageing policies, but what quality of life means in concrete terms for people in different stages of old age is rather unclear. This study presents a multi-dimensional model of care-related quality of life (crQoL) and, based on analyses of three Finnish cross-sectional datasets from the years 2004–2007, examines the distinctions between dimensions of QoL by age and gender, with a special focus on older home care clients. Correlation analyses (Pearson) and stepwise linear regression were applied to analyse variation in QoL by age group and the association between QoL and perceived quality of home care. The results suggest that individual QoL and the priorities of (physical, psychical, social, and environmental) dimensions in the assessment of QoL by older persons vary considerably and exhibit distinct profiles in different stages of ageing. In addition, four dimensions for good care corresponding to the crQoL model were identified and their empirical relevance demonstrated. From the perspective of older people in need of help, home care is not just about giving them the instrumental help they need to perform their daily activities, but rather about giving responsive care that reflects their personal preferences or their view on a “good life”, and treats them with dignity and respect. The criteria for the evaluation of quality of home care should reflect these insights, and policy measures should take these differences into account.
National Brand and Private Label Pricing and Promotional Strategy

In this paper I use a unique and rich data set on prices and promotions from major US supermarkets to examine the nature of National Brand and Private Label interaction. Private labels are priced and promoted competitively with NBs, in a manner suggesting that retails are careful not to lose private label market share during times of national brand promotions. The price margin between the two types of products continues to fall in US supermarkets, and the major determinants of the price differences between the two are promotional frequency and market concentration.
The energy consumption of desktop computers: measurement and savings potential

The energy consumption of desktop personal computers was studied at three Canadian Federal Government sites, and the potential for energy savings through power management investigated. The power draw of computers and their peripherals was measured using a portable meter, and use profiles were recorded using custom software. The measured plug loads were considerably lower than nameplate ratings. Use profiles from 94 computers indicated that there were long periods during both night and day when the computers were turned on but not being used, and it was predicted that significant energy savings could be achieved if electricity consumption was more closely tailored to actual usage. Two methods of realizing these savings were tested in the field. Stickers reminding users to switch off computers when they were not being used produced reductions in mean computer energy consumption of 14% over an eight week period. However, these savings diminished with time. An automatic power management system designed to switch off computers and peripherals after a user-specified period of inactivity produced reductions in mean computer energy consumption of 63%, while visual display unit mean energy consumption was reduced by 82%. These savings were maintained over an eight week period. >
Self-Noise Models of Seismic Instruments

Based on coherence analysis methods we develop a method for computing low self-noise models of seismic sensors. We calculate self-noise models for 11 different production seismometers. This collection contains the majority of sensors currently in use at Global Seismographic Network Stations. By developing these noise models, with a standard estimation method, we are able to make absolute comparisons between different models of seismic sensors. This also provides a method of identifying quality variations between two or more of the same model sensor. Studying Earth's free oscillations requires a large amount of seismic data with a high signal-to-noise ratio at long periods (Laske 2004). Recent tomographic studies using ambient seismic noise (Shapiro et al. 2005) also require the self-noise of seismic instruments to be below that of the Earth's ambient background noise, because as they use Earth noise as the seismic signal. It is also important when making temporary sensor deployments that the instrument's noise levels are below that of the signals being used in the study (Wilson et al. 2002). In order to verify that seismic instruments meet the above demands and other user requirements it is important from a testing standpoint, that one be able to measure the self-noise of seismic sensors and develop baselines for different models of seismic instruments. The different methods used to estimate self-noise of seismic sensors have made it difficult to do side-by-side comparisons of their performance (Hutt et al. 2009). This lack of a self-noise estimate standard makes it difficult to assess when a sensor's self-noise is above the manufacturers' specifications, indicating a possible problem with the sensor or noisy site conditions. In sensor development it is important to be able to compare a prototype sensor's self-noise to that of known self-noise levels of a reference sensor. On top of these complications some …
How people do relational reasoning? Role of problem complexity and domain familiarity

The goal of this paper is to study how people do relational reasoning.We present two studies that look at human performance in relational problems.Our results present the first evidence toward the role of problem complexity on performance.We did not find any evidence suggesting any role of familiarity with spreadsheets. The goal of this paper is to study how people do relational reasoning, such as selecting the grade of all students in a class with GPA (Grade Point Average) greater than 3.5. Literature in the field of psychology of human reasoning offer little insight as to how people solve relational problems. We present two studies that look at human performance in relational problems that use basic relational operators. Our results present the first evidence toward the role of problem complexity on performance as determined by the accuracy and discrimination rates. We also look at the role of familiarity with tabular representation of information, as found in spreadsheets for example, and other factors for relational reasoning, and show that familiarity does not play a significant role in determining performance in relational problem solving, which we found counterintuitive.
Evaluation and replication of impact damage to bicycle helmets

A group of 72 impacted bicycle helmets were collected, primarily from manufacturers with a crash replacement policy that encourages the return of damaged helmets. Each damaged helmet was thoroughly inspected and measured to determine the construction details and collision damage. Laboratory replication tests were then performed on selected samples using exemplar helmets to determine impact velocity and peak headform aceleration. The predominant impact location was the front left quarter and the replication studies indicate that the majority of impacts took place on flat surfaces from drop heights of 1 meter or less. Overall, it is evident that a large number of bicycle helmet users who have benefited from the use of a bicycle helmet, and future bicycle helmet standards must incorporate the protective requirements of this unique group.
Chiral mesophases of DNA

Abstract In the hexagonal columnar phase of chiral polymers a bias towards cholesteric twist competes with braiding along an average direction. When the chirality is strong, topological defects proliferate, leading to either a tilt grain boundary phase or a new “moire state” with twisted bond order. This moire phase can melt leading to a new phase: the chiral hexatic. I will discuss some recent experimental results from the NIH on DNA liquid crystals in the context of these theories.
Matthew Gentzkow, Winner of the 2014 Clark Medal

Abstract The 2014 John Bates Clark Medal of the American Economic Association was awarded to Matthew Gentzkow of the University of Chicago Booth School of Business. The citation recognized Matt's “fundamental contributions to our understanding of the economic forces driving the creation of media products, the changing nature and role of media in the digital environment, and the effect of media on education and civic engagement.” In addition to his work on the media, Matt has made a number of significant contributions to empirical industrial organization more broadly, as well as to applied economic theory. In this essay, I highlight some of these contributions.
Impacts of Trade and Agricultural Policies on the World Malt and Malting Barley Market

Major changes have been occurring in agricultural policies affecting world malt and malting barley production and trade. This paper analyzes effects of these changes on international trade and competition. A spatially disaggregated linear programing model of the world malt and malting barley sector is constructed and used to analyze effects of changes in European Union supply, European Union restitutions, the U.S. Export Enhancement Program subsidy regime, and import tariffs on malt and malting barley. Policy changes are found to generate substantial changes in trade flows and competitiveness between producing and exporting regions. De grands bouleversements secouent les politiques agricoles ressortissant a la production et aux echanges de malt et d'orge brassicole a l'echelle mondiale. Nous analysons ici les effets de ces changements sur les echanges et sur la concurrence internationaux. Au moyen d'un modele de programmation lineaire, desagrege dans l'espace, nous etudions les effets des changements sur la situation de l'approvisionnement et sur les restitutions a l'exportation dans l'Union Europeene, ainsi que sur le regime de subventions a l'exportation (US) et sur les tarifs douaniers a l'importation visant la consommation du malt et de l'orge brassicole. Nous avons constate que les grands changements strategiques modifiaient substantiellement les courants d'echange ainsi que la concurrentialite entre les regions de production et les regions d'exportation.
A synthetic approach to diaryl ethers using the Robinson annulation

Abstract An alternative synthetic approach to diaryl ethers has been developed. In the key transformation, Robinson annulation of nonracemic aldehydes 16a , b , derived from l -glutamic acid 5-methyl ester and phenoxymethylvinyl ketone, provided α-phenoxyenones 17a , b . The Cbz-protected oxazolidine 17b was further converted into the diaryl ether 18b utilizing an oxidative selenation protocol.
Cylindrical contact homology of subcritical Stein-fillable contact manifolds

We use contact handle decompositions and a stabilization process to compute the cylindrical contact homology of a subcritical Stein-fillable contact manifold with vanishing first Chern class, and show that it is completely determined by the homology of a subcritical Stein-filling of the contact manifold.
Shock formation in the presence of entropy gradients

The steepening of a normal compression wave into a shock in a homentropic flow field is understood well through the method of characteristics. In a non-homentropic flow field, however, shock formation from a compression wave is more complex. The effects of entropy (or sound speed) gradients on shock formation from a compression wave are determined using a wave front expansion in Cartesian and in spherical polar coordinates. The latter problem has application to the intense energy focusing of sonoluminescence, particularly when applied to a spherically collapsing gas. The principal result is an analytical criterion for the time and place of shock formation, for a wave propagating into a field of smoothly varying entropy.
Do Organizational Socialization Tactics Influence Newcomer Embeddedness and Turnover

The author proposes that socialization tactics influence newcomer turnover by embedding newcomers more extensively into the organization. Hypotheses are tested with a sample of newcomers in a large financial services organization. Results reveal that socialization tactics enable organizations to actively embed new employees; collective, fixed, and investiture tactics were positively related to on-the-job embeddedness. Results also indicate that on-the-job embeddedness is negatively related to turnover and mediates relationships between some socialization tactics and turnover.
Percolation on Finite Cayley Graphs

In this paper, we study percolation on finite Cayley graphs. A conjecture of Benjamini says that the critical percolation $p_c$ of any vertex-transitive graph satisfying a certain diameter condition can be bounded away from one. We prove Benjamini's conjecture for some special classes of Cayley graphs. We also establish a reduction theorem, which allows us to build Cayley graphs for large groups without increasing $p_c$.
Data Transformation in Two-Way Analysis of Variance

Abstract A procedure for choosing a power transformation so that data from a replicated two-way classification better satisfy the usual analysis of variance assumptions is described. The statistic proposed in this article is compared with the Box and Cox [7] likelihood procedure by empirical sampling. Its 95 percent confidence intervals performed at their nominal level, which was not true for the likelihood method. Point estimates for both techniques were the same on the average, although those based upon the likelihood statistic were somewhat less variable.
The optimal software licensing policy under quality uncertainty

A new service model has emerged which delivers application software and services over the Web on a lease or subscription basis. Our paper studies the optimal licensing policy of a software vendor that uses that business model. We look at software vendors that are both selling (at a posted price) or leasing their products where as lessor they guarantee that the lessee will always have the latest version of the software on their desktop. We address some of the specific issues of implementing this policy at the packaged software market, including the impact of network externality, negligible marginal production costs, and upgrade compatibility. We show that by properly defining their pricing structure, software vendors can segment the market and realize effective second-degree price discrimination and show how and when software vendors can maximize their profits through the use of this new licensing policy.
Initial impacts of the Ticket to Work program: estimates based on exogenous variation in Ticket mail months

This paper presents results from an impact analysis of the Ticket to Work (TTW) program, as implemented by the Social Security Administration (SSA) from 2002 through 2007. For new, young Social Security Disability beneficiaries, we use exogenous variation in the month of Ticket mailing to rigorously estimate impacts of TTW on beneficiary outcomes over a 48-month period following the start of Ticket mailings in the beneficiary’s state. We find substantial impacts on enrollment for employment services with TTW-qualified providers, but no consistent evidence of impacts on the number of months in which beneficiaries did not receive benefits because of work, or on other outcomes. H55; I38
Dynamic Rolling for a Modular Loop Robot

Reconfigurable modular robots have the ability to use different gaits and configurations to perform various tasks. A rolling gait is the fastest currently implemented gait available for traversal over level ground and shows dramatic improvements in efficiency. In this work, we analyze and implement a sensor-based feedback controller to achieve dynamic rolling for a loop robot. The robot senses its position relative to the ground and changes its shape as it rolls. This shape is such that its center of gravity is maintained to be in front of its contact point with the ground, so in effect the robot is continuously falling and thus accelerates forward. Using simulation and experimental results, we show how the desired shape can be varied to achieve higher terminal velocities. The highest velocity achieved in this work is 26 module lengths per second (1.6 m/s) which is believed to be the fastest gait yet implemented for an untethered modular robot. One of the major findings is that more elongated shapes achieve higher terminal velocities than rounder shapes. We demonstrate that this trend holds going up inclines as well as down. We show that rounder shapes have lower specific resistance and are thus more energy efficient. The control scheme is scalable to an arbitrary number of modules, shown here using eight to 14 modules.
Structural simplification of modular bond-graph models based on junction inactivity

Abstract The modular modeling paradigm facilitates the efficient building, verification and handling of complex system models by assembling them from general-purpose component models. A drawback of this paradigm, however, is that the assembled system models may have excessively complex structures for certain purposes due to the amount of detail in the component models that has been introduced to promote modularity. For example, a multibody system can be modeled using generic rigid-body models with 6 degrees-of-freedom (DoF) to represent the components of the system, but then constraints have to be added to the model to match the DoF of the system. This work presents a structural simplification technique that can detect such unnecessary complexities in a modular bond-graph system model and eliminate them without compromising accuracy. To this end, the activity concept in the literature is extended to define “inactivity” for junction elements, and simplification is obtained by detecting and eliminating inactive junction elements and by propagating the implications. It is shown by example that this simple idea can result in models that are conceptually and computationally more efficient than the original modular models. The realization-preserving and input-dependent characteristics of this approach are highlighted.
Boundary layer flow of air over water on a flat plate

A non-similar boundary layer theory for air blowing over a water layer on a flat plate is formulated and studied as a two-fluid problem in which the position of the interface is unknown. The problem is considered at large Reynolds number (based on x), away from the leading edge. A simple non-similar analytic solution of the problem is derived for which the interface height is proportional to x(sub 1/4) and the water and air flow satisfy the Blasius boundary layer equations, with a linear profile in the water and a Blasius profile in the air. Numerical studies of the initial value problem suggests that this asymptotic, non-similar air-water boundary layer solution is a global attractor for all initial conditions.
The capacity of hybrid quantum memory

The general stable quantum memory unit is a hybrid consisting of a classical digit with a quantum digit (qudit) assigned to each classical state. The shape of the memory is the vector of sizes of these qudits, which may differ. We determine when N copies of a quantum memory /spl Ascr/ embed in N(1+/spl ogr/(1)) copies of another quantum memory /spl Bscr/. This relationship captures the notion that/spl Bscr/ is as at least as useful as /spl Ascr/ for all purposes in the bulk limit. We show that the embeddings exist if and only if for all p/spl ges/1, the p-norm of the shape of /spl Ascr/ does not exceed the p-norm of the shape of /spl Bscr/. The log of the p-norm of the shape of /spl Ascr/ can be interpreted as the maximum of S(/spl rho/)+H(/spl rho/)/p (quantum entropy plus discounted classical entropy) taken over all mixed states /spl rho/ on /spl Ascr/. We also establish a noiseless coding theorem that justifies these entropies. The noiseless coding theorem and the bulk embedding theorem together say that either /spl Ascr/ blindly bulk-encodes into /spl Bscr/ with perfect fidelity, or A admits a state that does not visibly bulk-encode into/spl Bscr/with high fidelity. In conclusion, the utility of a hybrid quantum memory is determined by its simultaneous capacity for classical and quantum entropy, which is not a finite list of numbers, but rather a convex region in the classical-quantum entropy plane.
A modified model reference adaptive control scheme for improved transient performance

The author proposes a modified model reference adaptive control (MRAC) scheme aimed at improving the transient performance of adaptive systems while maintaining the ideal asymptotic properties possessed by standard MRAC. In the modified scheme, the estimation error, which is generated by the identification scheme, is used directly as a control signal to counteract errors resulting from the certainty equivalence design. It is shown that the modified scheme provides essentially the same stability and robustness properties as the standard adaptive MRAC approach but with the transient performance substantially improved. Simulation results are presented to illustrate the effectiveness of the proposed scheme. >
Ring-closing metathesis: A facile construct for alkaloid synthesis*

Ring-closing metathesis has been found to be a highly effective reaction for the synthesis of functionalized, bridged nitrogen heterocycles. The utility of the process has been established in several case studies, including a facile synthesis of the tropane ring system and efficient, enantioselective syntheses of the natural products (-)-peduncularine and (+)-ana- toxin-a.
Supermassive black hole growth and merger rates from cosmological N-body simulations

Understanding how seed black holes (BHs) grow into intermediate-mass and supermassive black holes (IMBHs and SMBHs, respectively) has important implications for the duty cycle of active galactic nuclei (AGN), galaxy evolution and gravitational wave astronomy. Most studies of the cosmological growth and merger history of BHs have used semianalytic models and have concentrated on SMBH growth in luminous galaxies. We have developed a ‘hybrid method’ that combines high-resolution cosmological N-body simulations for the haloes’ merger history, with semi-analytical recipes for BH pair dynamics and BH gas accretion. We track the assembly of BHs over a large range of final masses ‐ from seed BHs to SMBHs ‐ over widely varying dynamical histories. We used the dynamics of dark matter haloes to track the evolution of seed BHs in three different gas accretion scenarios. We have found that growth of a Sagittarius
Computing dynamic output feedback laws

The pole placement problem asks to find laws to feed the output of a plant governed by a linear system of differential equations back to the input of the plant so that the resulting closed-loop system has a desired set of eigenvalues. Converting this problem into a question of enumerative geometry, efficient numerical homotopy algorithms to solve this problem for general multiple-input-multiple-output systems have been proposed recently. Despite the wider application range of dynamic feedback laws, the realization of the output of the numerical homotopies as a machine to control the plant in the time domain has not been addressed before. In this note, we present symbolic-numeric algorithms to turn the solution to the question of enumerative geometry into a useful control feedback machine. We report on numerical experiments with our publicly available software PHCpack and illustrate its application on various control problems from the literature.
Fiber-optic gyroscope with polarization-holding fiber

A fiber gyroscope is reported that uses polarization-holding fiber in the coil, the phase modulator, and the coupler. The random-drift coefficient, calculated from rms noise levels, was 8.10−4deg/h, within a factor of 2 of an experimentally determined quantum and thermal limit. White-noise behavior was observed for integration time constants from 1 to 40 sec. Device characteristics and performance are presented.
A new protocol for the integration of voice and data over PRMA

In packet reservation multiple access (PRMA) the receiver in the mobile terminal is required to listen continuously to monitor the acknowledgment messages broadcasted at the end of every time slot. A new scheme for the integration of voice and data based on PRMA is proposed. The voice and the data subsystems are logically separated. The total available bandwidth is divided into three regions-voice information, voice contention, and data regions. The available bandwidth is dynamically partitioned between the above three regions subject to the fulfillment of the quality of service (QoS) requirements of the voice users. The voice subsystem has been modeled as a Markov chain and an exact analytical method used to compute the voice packet dropping probability is described. A nonlinear programming problem is formulated to optimize the bandwidth allocated for the data users. Solutions to this nonlinear programming problem that are very close to optimum have been obtained heuristically. Numerical results indicate that a significant amount of data traffic can be supported without sacrificing the voice capacity of the system.
Metastability and the Casimir effect in micromechanical systems

Electrostatic and Casimir interactions limit the range of positional stability of electrostatically actuated or capacitively coupled mechanical devices. We investigate this range experimentally for a generic system consisting of a doubly clamped Au suspended beam, capacitively coupled to an adjacent stationary electrode. The mechanical properties of the beam, both in the linear and nonlinear regimes, are monitored as the attractive forces are increased to the point of instability. There pull-in occurs, resulting in permanent adhesion between the electrodes. We investigate, experimentally and theoretically, the position-dependent lifetimes of the free state (existing prior to pull-in). We find that the data cannot be accounted for by simple theory; the discrepancy may be reflective of internal structural instabilities within the metal electrodes.
Reading newspaper text

The authors describe a method for segmenting a newspaper page image into labeled macro components (blocks) and recognizing the content. Connected component analysis is used to segment a newspaper image into several rectangular blocks and to filter connected components into character and noncharacter components. Textural analysis is then used to classify the remaining noncharacter components into graphics and photographs. Experimental results indicate that these techniques work very well. >
Dipole Relaxation Losses in DNA

The electrodynamic response of DNA in the millimeter wave range is investigated. By performing measurements under a wide range of humidity conditions and comparing the response of single-stranded DNA and double-stranded DNA, we show that the appreciable ac conductivity of DNA is not due to photon-assisted hopping between localized states but is instead due to dissipation from dipole motion in the surrounding water helix. Such a result, where the conductivity is due to the constrained motion of overdamped dipoles, reconciles the vanishing dc conductivity of DNA with the considerable ac response.
Quantifying cosmic superstructures

The large-scale structure (LSS) found in galaxy redshift surveys and in computer simulations of cosmic structure formation shows a very complex network of galaxy clusters, filaments and sheets around large voids. Here, we introduce a new algorithm, based on a minimal spanning tree, to find basic structural elements of this network and their properties. We demonstrate how the algorithm works using simple test cases and then apply it to haloes from the Millennium Run simulation. We show that about 70 per cent of the total halo mass is contained in a structure composed of more than 74000 individual elements, the vast majority of which are filamentary, with lengths of up to 15 h -1 Mpc preferred. Spatially more extended structures do exist, as do examples of what appear to be sheet-like configurations of matter. What is more, LSS appears to be composed of a fixed set of basic building blocks. The LSS formed by mass selected subsamples of haloes shows a clear correlation between the threshold mass and the mean extent of major branches, with cluster-size haloes forming structures whose branches can extend to almost 200 h -1 Mpc - the backbone of LSS to which smaller branches consisting of smaller haloes are attached.
Evaluating Throwing Ability in Baseball

We present a quantitative analysis of throwing ability for major league outfielders and catchers. We use detailed game event data to tabulate success and failure events in outfielder and catcher throwing opportunities. We attribute a run contribution to each success or failure which is tabulated for each player in each season. We use four seasons of data to estimate the overall throwing ability of each player using a Bayesian hierarchical model. This model allows us to shrink individual player estimates towards an overall population mean depending on the number of opportunities for each player. We use the posterior distribution of player abilities from this model to identify players with significant positive and negative throwing contributions. Our results for both outfielders and catchers are publicly available.
Age and Menopausal Effects of Hormonal Birth Control and Hormone Replacement Therapy in Relation to Breast Cancer Risk

It is unclear whether breast cancer risk varies by age and menopausal status in relation to use of hormonal birth control (HBC) and hormone replacement therapy (HRT), taken singly or cumulatively. The authors utilized data from 1,478 cases and 1,493 controls aged 20-98 years with known menopausal status, who had participated in a population-based, case-control study conducted on Long Island during 1996-1997. Exogenous hormone use over the lifecourse was assessed by use of memory aids. The authors examined associations among women in these subgroups: premenopausal (n = 968), postmenopausal or = 65 years (n = 958). Among premenopausal women, risk was increased for ever use of HBC (odds ratio (OR) = 1.37, 95% confidence interval (CI): 1.04, 1.81) or HRT (OR = 1.81, 95% CI: 1.17, 2.81) and was pronounced among women reporting use of both HBC and HRT (OR = 2.59, 95% CI: 1.50, 4.46), long-term HRT use (OR = 3.93, 95% CI: 1.43, 10.84), or estrogen-plus-progestin therapy (OR = 3.51, 95% CI: 1.45, 8.49). There was no effect of ever HBC use among postmenopausal women aged less than 65 years, but risk was modestly elevated for more than 5 years of HRT use (OR = 1.41, 95% CI: 1.00, 1.99). Among postmenopausal women aged 65 years or more, odds ratios for HBC or HRT use were around the null. These results emphasize that timing of exogenous hormone use is important. Women who used these hormones before menopause had elevated risks, but the harmful effects began to decline with age after menopause.
O–H hydrogen bonding promotes H-atom transfer from α C–H bonds for C-alkylation of alcohols

The efficiency and selectivity of hydrogen atom transfer from organic molecules are often difficult to control in the presence of multiple potential hydrogen atom donors and acceptors. Here, we describe the mechanistic evaluation of a mode of catalytic activation that accomplishes the highly selective photoredox α-alkylation/lactonization of alcohols with methyl acrylate via a hydrogen atom transfer mechanism. Our studies indicate a particular role of tetra-n-butylammonium phosphate in enhancing the selectivity for α C–H bonds in alcohols in the presence of allylic, benzylic, α-C=O, and α-ether C–H bonds.
Coupling Reactions of α-(N-Carbamoyl)alkylcuprates with Enol Triflates Derived from Cyclic β-Keto Esters: A Facile Approach to γ-Carbamoyl-α,β-enoates

α-(N-Carbamoylalkyl)cuprates couple with enol triflates derived from carbocyclic and heterocyclic (i.e., piperidinones) β-keto esters. Product yields are higher with the alkyl(cyano)cuprates [i.e., RCu(CN)Li, 56−93%] than with the dialkylcuprate reagents (i.e., R2CuLi·LiCN). An enol nonaflate works as well as the corresponding enol triflate. A facile synthetic route to γ-amino α,β-enoates not readily prepared from γ-keto-α,β-enoates is thus established. The γ-amino-α,β-enoates, available via N-Boc deprotection, can be cyclized to annulated pyrrolin-2-ones.
Performance of the ALS injection system

We started commissioning the Advanced Light Source (ALS) storage ring on January 11, 1993. The stored beam reached 60 mA on March 24, 1993 and 407 mA on April 9, 1993. The fast pace of storage ring commissioning can be attributed partially to the robust injection system. We describe the operating characteristics of the ALS injection system. >
Close Galaxy Counts as a Probe of Hierarchical Structure Formation

StandardCDM predicts that the major merger rate of galaxy-size dark matter halos rises rapidly with increasing redshift. The average number of close companions per galaxy, Nc is often used to infer the galaxy merger rate. Recent observational studies suggest that Nc evolves very little with redshift, in apparent conflict with theoretical expectations for the merger rate of dark matter halos. We use a "hybrid" N-body simulation plus analytic substructure model to build theoretical gala xy catalogs and measure Nc in the same way that it is measured in observed galaxy samples. When we identify dark matter subhalos with galaxies, we show that the observed lack of close pair count evolution arises naturall y. This unexpected result is caused by the fact that there are multiple subhalos (galaxies) per host dark matter halo, and observed pairs tend to reside in massive halos that contain several galaxies. There are fewer massive host halos at early times and this dearth of galaxy groups at high redshift compensates for the fact that the merger rate per host halo is higher in the past. We compare our results to z ∼ 1 DEEP2 data and to z ∼ 0 data that we have compiled from the SSRS2 and the UZC redshift surveys. The observed close companion counts match our simulation predictions well, provided that we assume a monotonic mapping between galaxy luminosity and the maximum circular velocity of each subhalo in our catalogs at the time when it was first accreted o nto its host halo. This strongly suggests that satellite galaxies are significantly more resilient to mass loss than are dissipationless dark matter subhalos. Finally, we argue that while Nc does not provide a direct measure of the merger rate of host dark matter halos, it offers a powerful means to constrain both the Halo Occupation Distribution and the spatial distribution of galaxies within dark matter halos. Interpreted in this way, close pair counts provide a useful test of galaxy formation processes on ∼10-100 kpc scales.
Synthesis, characterization, and reactivity of new alkylgallium acetylides

Abstract Reaction of Me2GaCl and LiCCSiMe3 or R2GaCl (R  Me, tBu) and LiCCPh (benzene, 70°C) gives [Me2GaCCSiMe3]2 and [R2GaCCPh]2 in 62%, 58%, and 71% yields, respectively. The gallium acetylides were characterized by IR, Raman, and NMR (1H, 13C, 13C{1H}) spectroscopy. Reactions of the dimethylgallium acetylides and phosphines (R2PH; R  Et, iPr) (toluene, 110-20°C) give HCCSiMe3 or HCCPh and the corresponding dimethylgallium dialkylphosphides [Me2GaPR2]n (R  Et, n = 3, iPr, n = 2).
Computing Persistent Homology

We show that the persistent homology of a filtered d-dimensional simplicial complex is simply the standard homology of a particular graded module over a polynomial ring. Our analysis establishes the existence of a simple description of persistent homology groups over arbitrary fields. It also enables us to derive a natural algorithm for computing persistent homology of spaces in arbitrary dimension over any field. This result generalizes and extends the previously known algorithm that was restricted to subcomplexes of S3 and Z2 coefficients. Finally, our study implies the lack of a simple classification over non-fields. Instead, we give an algorithm for computing individual persistent homology groups over an arbitrary principal ideal domain in any dimension.
Zeta function on surfaces of revolution

In this paper we applied the contour integral method for the zeta function associated with a differential operator to the Laplacian on a surface of revolution. Using the WKB expansion, we calculated the residues and values of the zeta function at several important points. The results agree with those obtained from the heat kernel expansion. We also obtained a closed form formula for the determinant of the Laplacian on such a surface.
An efficient and selective synthesis of nakienone A involving a novel protocol for α-alkenylation of ketones via palladium-catalyzed alkenyl-alkenyl coupling

Abstract Nakienone A was synthesized for the first time from 3-methoxy-2-cyclopentenone, dienyl iodide 7, and LiCH2OMOM in 8 steps in 26% overall yield with full control of the alkene geometry using the Pd-catalyzed cross coupling reaction of a cyclopentenylzinc derivative 6a with 7 as a key step.
The Value of Coverage in the Medicare Advantage Insurance Market

Abstract This paper examines the impact of coverage on demand for health insurance in the Medicare Advantage (MA) insurance market. Estimating the effects of coverage on demand poses a challenge for researchers who must consider both the hundreds of benefits that affect out-of-pocket costs (OOPC) to consumers, but also the endogeneity of coverage. These problems are addressed in a discrete choice demand model by employing a unique measure of OOPC that considers a consumer’s expected payments for a fixed bundle of health services and applying instrumental variable techniques to address potential endogeneity bias. The results of the demand model show that OOPC have a significant effect on consumer surplus and that not instrumenting for OOPC results in a significant underestimate of the value of coverage.
THE EFFECT OF LINE-OF-SIGHT TEMPERATURE VARIATION AND NOISE ON DUST CONTINUUM OBSERVATIONS

We investigate the effect of line-of-sight temperature variations and noise on two commonly used methods to determine dust properties from dust-continuum observations of dense cores. One method employs a direct fit to a modified blackbody spectral energy distribution (SED); the other involves a comparison of flux ratios to an analytical prediction. Fitting fluxes near the SED peak produces inaccurate temperature and dust spectral index estimates due to the line-of-sight temperature (and density) variations. Longer wavelength fluxes in the Rayleigh-Jeans part of the spectrum (≳ 600 μm for typical cores) may more accurately recover the spectral index, but both methods are very sensitive to noise. The temperature estimate approaches the density-weighted temperature, or "column temperature," of the source as short wavelength fluxes are excluded. An inverse temperature-spectral index correlation naturally results from SED fitting, due to the inaccurate isothermal assumption, as well as noise uncertainties. We show that above some "threshold" temperature, the temperatures estimated through the flux ratio method can be highly inaccurate. In general, observations with widely separated wavelengths, and including shorter wavelengths, result in higher threshold temperatures; such observations thus allow for more accurate temperature estimates of sources with temperatures less than the threshold temperature. When only three fluxes are available, a constrained fit, where the spectral index is fixed, produces less scatter in the temperature estimate when compared to the estimate from the flux ratio method.
Within the Tent and at the Crossroads: Travel and Gender Identity among the Tuareg of Niger

This essay examines the shaping of gender relations in travel among the seminomadic Tuareg in the Niger Republic. Expressive forms including narrative, conversation, poetry, and song articulate ambivalence toward changing travel practices in a society based on movement, and afundamental preoccupation with inside, outside, and the borders that separate them. Men's and women's travel experiences undermine existing institutions, consequently enmeshing gender identity in new power relations in other domains. These Tuareg data challenge some tendencies of transnational theory to elevate the transcultural to the universal, and offer a perspective on the interaction between gender and forms of hegemony.