cssi/SciSciGPT-SciSciNet huggingface dataset:
Proposed modifications to ice accretion/icing scaling theory

The difficulty of conducting full-scale icing tests has long been appreciated. Testing in an icing wind tunnel has been undertaken for decades. While aircraft size and speeds have increased, tunnel facilities have not, thus making subscale geometric tests a necessity. Scaling laws governing these tests are almost exclusively based on analysis performed over 30 years ago and have not been rigorously validated. The following work reviews past scaling analyses and suggests revision to these analyses based on recent experimental observation. It is also suggested, based on the analysis contained herein, that current ice accretion predictive technologies, such as LEWICE when utilized in the glaze ice accretion regime, may need upgrading to more accurately estimate the rate of ice build-up on aerodynamic surfaces.
Synthesis of a natural product-inspired eight-membered ring lactam library via ring-closing metathesis

We have prepared a novel speculative eight-membered lactam demonstration library based on the skeletal structure of the potent antitumor marine natural product octalactin A. The basic scaffold was readily constructed in a convergent fashion via ring-closing metathesis chemistry from the corresponding diene amides. A cursory examination of the biological properties of the library validates the relevance and significance of these structures.
Bending effects on structural dynamic instabilities of transonic wings

Nonclassical flutter has been observed during transonic conditions associated with flight and wind tunnel testing of various fighter and bomber aircraft As contrasted with classical flutter the underlying mechanism has been ascribed to a phase lag between lift variations and wing motions Based on the observations that the wing oscillations were restricted to bending mode shapes similar to the free fundamental, the phenomenon was idealized as the lift induced forced oscillation of a Cantilever beam simulating the wing. Coupling with the aerodynamics occurs through the beam equation forcing term, representing the lift, and the tangency boundary condition for the unsteady transonic small disturbance equation for the latter Strip theory has been used with a suitably revised version of LTRAN2 to supply the aerodynamic input The resulting time integration algorithm provides a procedure to determine the destabilizing effects of sweepback Computations with the method closely predict flutter frequencies observed for the HiMAT canard during wind tunnel testing, as well as for the B-l wing in flight tests in two out of three cases Qualitative behavior of the oscillation agrees for these conditions For the third case, damped oscillations are predicted rather than the amplified ones observed Reasons for the discrepancy are provided, involving the second bending mode of these oscillations in contrast to the fun damental assumed by the current approach Specific recommendations for refinements of the procedure in volving inclusion of modal coupling analysis of limit cycle aspects and three dimensional phenomena are given
Accessing nitrosocarbonyl compounds with temporal and spatial control via the photoredox oxidation of N -substituted hydroxylamines

Abstract Photoredox catalysis is employed to generate highly reactive acylnitroso species from hydroxamic acid derivatives. The conditions are shown to be comparable to a previously developed transition metal aerobic oxidation and are amenable to a range of transformations including Diels–Alder and ene reactions. This unique application of such an approach gives access to temporal and spatial control in nitroso chemistry.
Resolving time-series structure with a controlled wavelet transform

Wavelet transforms are powerful techniques that can decompose time series into both time and frequency components. Their application to experimental data has been hindered by the lack of a straightforward method to handle noise. A noise reduction technique, developed recently for use in wavelet cluster analysis in cosmology and astronomy, is adapted here for time-series data. Noise is filtered using control surrogate data sets generated from randomized aspects of the original time series. The method is a powerful extension of the wavelet transform that is readily applied to the detection of structure in stationary and nonstationary time series.
Early results of a prospective study of hormone therapy for patients with locally advanced prostate carcinoma

BACKGROUND Locally advanced prostate carcinoma is usually not curable with surgery or radiation therapy. Primary hormone therapy is an alternative therapeutic option, but contemporary prospective studies of the outcomes of such therapy are not available. METHODS The authors conducted a prospective, hospital-based study of gonadal androgen ablation with deferred antiandrogen therapy in 103 men with prostate carcinoma clinically classified as T3-4NXM0. The median potential follow-up was 51 months (range, 36-74 months), and the median period of observation was 43 months (range, 6-74 months). RESULTS Each patient experienced regression of the primary tumor, and none experienced significant morbidity from the primary tumor during the study period. The projected 5-year cause specific, metastasis free, PSA disease free (no PSA elevation > 1.0 ng/mL after the beginning of antiandrogen therapy), and all-cause survival rates were 84%, 84%, 68%, and 58%, respectively. CONCLUSIONS Primary hormone therapy is a reasonable treatment option for locally advanced prostate carcinoma in elderly men or in men with significant comorbid disease who request therapeutic intervention. Cancer 1998;82:1112-7. © 1998 American Cancer Society.
Synthesis of Dihydrobenzofurans via Palladium-Catalyzed Annulation of 1,3-Dienes by o-Iodoaryl Acetates

The palladium-catalyzed annulation of 1,3-dienes by o-iodoaryl acetates provides an efficient approach to biologically interesting dihydrobenzofurans. The annulation is believed to proceed via (1) oxidative addition of the aryl iodide to Pd(0), (2) syn-addition of the resulting arylpalladium complex to the 1,3-diene, (3) intramolecular coordination of the phenolic oxygen to the Pd center, (4) hydrolysis of the acetyl group, and (5) reductive elimination of Pd(0), which regenerates the catalyst. This reaction is quite general, regioselective, and stereoselective, and a wide variety of terminal, cyclic, and internal 1,3-dienes, as well as electron-rich and electron-deficient o-iodoaryl acetates, can be utilized.
Aromatic annelation. A synthesis of (±)-3-methyl-8,14-dehydromorphinan.

Abstract (±)-3-Methyl-8,14-dehydromorphinan has been prepared by forming the aromatic ring in the late stages of the synthesis.
Generation of confinement and other nonperturbative effects by infrared gluonic degrees of freedom

Recent progress in understanding the emergence of confinement and other nonperturbative effects in the strong interaction vacuum is reviewed. Special emphasis is placed on the role of different types of collective infrared gluonic degrees of freedom in this respect. After a survey of complementary approaches, models of the QCD vacuum based on center vortices, Abelian magnetic monopoles and topological charge lumps such as instantons, merons and calorons are examined. Both the physical mechanisms governing these models as well as recent lattice studies of the respective degrees of freedom are reviewed.
Catalysis by Transition Metals: Metal-Carbon Double and Triple Bonds

Several well-characterized transition metal catalysts contain a metal-carbon double bond or a metal-carbon triple bond. In other homogeneous (or heterogeneous) catalyst systems in which the metal is likely to be in a relatively high oxidation state, such as molybdenum(VI) or tungsten(VI), metal-carbon multiple bonds may play an important role. Some recent results suggest that even supposedly well understood reactions such as ethylene polymerization may actually involve catalysts that behave as if they contained a metal-carbon double bond instead of a metal-carbon single bond. The chemistry of metal-carbon double and triple bonds should eventually complement and perhaps. overlap the known chemistry of complexes containing metal-oxygen double bonds or metal-nitrogen triple bonds, respectively; unique catalytic reactions involving carbon, nitrogen, and oxygen ligands multiply bonded to transition metals are therefore possible.
SenseTK: A Multimodal, Multimedia Sensor Networking Toolkit

This paper describes the design and implementation of a multi-modal, multimedia capable sensor networking framework called SenseTK. SenseTK allows application writers to easily construct multi-modal, multimedia sensor networks that include both traditional scalar-based sensors as well as sensors capable of recording sound and video. The distinguishing features of such systems include the need to push application processing deep within the sensor network, the need to bridge extremely low power and low computation devices, and the need to distribute and manage such systems. This paper describes the design and implementation of SenseTK and provides several diverse examples to show the flexibility and unique aspects of SenseTK. Finally, we experimentally measure several aspects of SenseTK.
Excited States of Even-Even Nuclei

A general survey of excited states of even-even nuclei yields the following results: The $n\mathrm{th}$ excited state has usually a spin $I\ensuremath{\le}2n$. For $n=1$, the assignment $I=2+(\mathrm{even}\mathrm{parity})$ is compatible with experimental results for 66 out of 68 nuclei investigated. For $n=2$, of 26 nuclei investigated, about one-third have $I=2+$, one-third $I=4+$, and one-third miscellaneous spins of both even and odd parities. The energy of the first excited state plotted against the number of protons or neutrons in the nucleus varies rather smoothly and reaches maxima at closed shells. Wherever the first excited state is very low, e.g., in the rare earths region and for the heavy elements from thorium up, the one-particle model for odd $A$ nuclei is likely to break down except for the ground state. The lack of isomers of odd proton nuclei below magic number 82 may be due to this fact. The average energy of the first excited state of the even-even core in this region is of the order of 0.1 Mev, whereas this energy is of the order of 0.5 Mev for the core of the corresponding odd neutron nuclei ($Nl82$). Isomerism in even-even nuclei is discussed. The results are compared with theoretical predictions derived from an extended $j\ensuremath{-}j$ coupling model and from the liquid drop model of the nucleus.
Boundedness of the hessian of a biharmonic function in a convex domain

We consider the Dirichlet problem for the biharmonic equation on an arbitrary convex domain and prove that the second derivatives of the variational solution are bounded in all dimensions.
Nonaqueous diazotization of 4-amino-3-arylisothiazole-5-carboxylate esters

4-Amino-3-arylisothiazole-5-carboxylate esters are converted to the corresponding desamino, chloro, bromo, and iodo esters by processes involving nonaqueous diazotization. These related procedures open up the possibility for the conversion of readily available heterocyclic ortho-amino esters and nitriles to related heterocyclic derivatives, which are not easily obtained by alternate routes.
4,4,14α-trimethyl 9β,19-cyclo-5α-26-homocholesta-24,26-dien-3β-ol: a potent mechanism-based inactivator of Δ24(25)- to Δ25(27)-sterol methyl transferase

Abstract The title compound (4A) was synthesized and tested as a mechanism-based inactivator of the sterol methyl transferase (SMT) enzyme from Prototheca wickerhamii . Using cycloartenol as substrate, 4A was found to exhibit time-dependent inactivation kinetics, generating a K i value of 30 μM and K inact value of 0.30 min −1 .
On stars, their evolution and their stability

The Nobel lecture of Chandrasekhar is printed in which he describes the basic processes that determine the life history of a star with particular emphasis on the roles of stellar mass and radiation pressure. (AIP)
Approaches of FIR system identification with noisy data using higher order statistics

The problem of estimating the parameters of a moving average model from the cumulant statistics of the noisy observations of the system output is discussed. The system is driven by an independently identically distributed nonGaussian sequence that is not observed. The noise is additive and may be colored and nonGaussian. Following some existing linear parametric approaches to this problem, a linear method and a modification to an existing linear method are proposed for consistent parameter estimation in measurement noise under the assumption that the system order is known. Both recursive closed-form and batch least-squares versions of the parameter estimators are presented. The existing and the proposed linear methods utilize only a partial set of the relevant output statistics (this restriction being necessary to obtain a linear estimator), whereas there exist nonlinear method that exploit a much larger set of output statistics. A simulation example where two existing linear methods and the two new methods are compared to two existing nonlinear methods is presented. >
Reactions of several monosaccharide-derived alcohols with p-acetamidobenzenesulfonyl azide and DBU

Abstract Attempted diazo transfer to 1-O-(2-phenylacetyl)-2,3;5,6-di-O-isopropylidene-α- d -mannofuranose using p-acetamidobenzenesulfonyl azide (p-ABSA) and DBU as base affords 1-O-(2-diazo-2-phenylacetyl)-2,3;5,6-di-O-isopropylidene-α- d -mannofuranose in low yield along with 2,3;5,6-di-O-isopropylidene-α- d -mannofuranose, 1-azido-2,3;5,6-di-O-isopropylidene-β- d -mannofuranose, as well as the unreacted starting material. The azido sugar likely arises from α-mannofuranosyl sulfonate ester formation, through displacement of azide from p-ABSA by the sugar lactol, followed by stereospecific displacement by azide anion on the furanosyl sulfonate ester. This outcome has been studied further with the conditions being applied to several common monosaccharide derivatives. Accessible substrates afford the azido sugar in an overall one-pot alcohol-to-azide conversion, while hindered substrates yield the sulfonate esters.
A Synthetically Useful Regioselective Epoxide Ring-Opening Procedure

Abstract The reaction of alcohols with epoxides in the presence of boron trifluoride etherate has been investigated and found to proceed with variable regioselectivity depending on the substituents attached to the oxirane ring.
Optical eye models for gaze tracking

The traditional "bottom-up" approach to video gaze tracking consists of measuring image features, such as the position of the pupil, corneal reflex, limbus, etc. These measurements are mapped to gaze angles using coefficients obtained from calibration data, collected as a cooperative subject voluntarily fixates a series of known targets. This may be contrasted with a "top-down" approach in which the pose parameters of a model of the eye are adjusted in conjunction with a camera model to obtain a match to image data. One advantage of the model-based approach is provided by robustness to changes in geometry, in particular the disambiguation of translation and rotation. A second advantage is that the pose estimates obtained are in absolute angular units (e.g., degrees); traditional calibration serves only to determine the relation between the visual and optical axes, and provide a check for the model. While traditional grid calibration methods may not need to be applied, a set of views of the eye in a variety of poses is needed to determine the model parameters for an individual. When relative motion between the head and the camera is eliminated (as with a head-mounted camera), the model parameters can be determined from as few as two images. A single point calibration is required to determine the angular offset between the line-of-sight and the observed optical axis.
Constraints on the size of the Vredefort impact crater from numerical modeling

— The Vredefort structure in South Africa was created by a meteorite impact about two billion years ago. Since that time, the crater has been deeply eroded; so to estimate its original size, researchers have had to rely heavily upon comparison to other terrestrial impact structures. Recent estimates of the original crater diameter range from 160 km to as much as 400 km. In this study, we combined the capabilities of both hydrocode and finite-element modeling, using the former to predict where the pressure of an impact-generated shock wave would have been high enough to form planar deformation features (PDFs) and shatter cones and the latter to follow the subsequent displacement of these shock isobars during the collapse of the crater. We established constraints on the sizes of the projectile and the transient crater (and, thus, on the size of the final crater) by comparing the observed locations of PDFs around Vredefort to the results of our simulations of impacts by projectiles of various sizes. These simulations indicate that a rocky projectile with a diameter of ∼10 km, impacting vertically at a velocity of 20 km/s generates shock pressures that are consistent with the distribution of PDFs around Vredefort. These projectile parameters correspond to a transient crater ∼80 km in diameter or a final crater ∼120–160 km in diameter. Allowing for uncertainties in our modeling procedures, we consider final craters 120 to 200 km in diameter to be consistent with the observed locations of PDFs at Vredefort. The shock pressure contour corresponding to the formation of shatter cones is almost horizontal near the surface, making the locations of these features less useful constraints on the crater size. However, they may provide a constraint on the amount of erosion that has occurred since the impact.
Some Elementary Consequences of Perelman’s Canonical Neighborhood Theorem

In this purely expository note, we deduce a few known direct consequences of Perelman’s canonical neighborhood theorem for 3-dimensional Ricci flow and compactness theorem for 3-dimensional κ-solutions. These corollaries regard elementary properties of 3-dimensional singularity models and κ-solutions.
A formally verified proof of the prime number theorem

The prime number theorem, established by Hadamard and de la Vallee Poussin independently in 1896, asserts that the density of primes in the positive integers is asymptotic to 1/ln x. Whereas their proofs made serious use of the methods of complex analysis, elementary proofs were provided by Selberg and Erdos in 1948. We describe a formally verified version of Selberg's proof, obtained using the Isabelle proof assistant.
Geometric Sufficient Conditions for Compactness of the Complex Green Operator

We establish compactness estimates for \(\overline{\partial}_{M}\) on a compact pseudoconvex CR-submanifold M of ℂn of hypersurface type that satisfies the (analogue of the) geometric sufficient conditions for compactness of the \(\overline{\partial}\)-Neumann operator given in (Straube in Ann. Inst. Fourier, 54(3):699–710, 2004; Munasinghe and Straube in Pac. J. Math., 232(2):343–354 2007). These conditions are formulated in terms of certain short time flows in complex tangential directions.
ANALYSIS OF A MATHEMATICAL MODEL OF ISCHEMIC CUTANEOUS WOUNDS

Chronic wounds represent a major public health problem affecting 6.5 million people in the United States. Ischemia represents a serious complicating factor in wound healing. In this paper we analyze a recently developed mathematical model of ischemic dermal wounds. The model consists of a coupled system of PDEs in the partially healed region, with the wound boundary as a free boundary. The extracellular matrix (ECM) is assumed to be viscoelastic, and the free boundary moves with the velocity of the ECM at the boundary of the open wound. The model equations involve the concentrations of oxygen, cytokines, and the densities of several types of cells. The ischemic level is represented by a parameter which appears in the boundary conditions, $0\leq\gamma<1$; $\gamma$ near 1 corresponds to extreme ischemia and $\gamma=0$ corresponds to normal nonischemic conditions. We establish global existence and uniqueness of the free boundary problem and study the dependence of the free boundary on $\gamma$.
A translational couch technique for total body irradiation.

We have constructed a computer controlled translational couch to administer total body irradiation reproducibly and safely. The system has replaced the previous stationary anterior-posterior technique in our institution and 30 plus patients have been treated with it so far. In this technique, patients comfortably lie on a couch in supine and prone positions and are transported slowly through a narrow beam with the gantry in an upright position. Dose to the patient is determined by the couch velocity that is calculated based on physical parameters such as patients dimensions, beam geometry, and machine dose rate. In our design, the couch velocity is continuously updated to compensate for machine dose rate fluctuations. The translational couch technique provides better dose uniformity within the patient compared to fixed beam techniques, and allows a more precise shielding block placement for organs at risk. At the same time, it presents a special challenge for dosimetry calculations. A dosimetry parameter is introduced that converts the moving beam output to the fixed beam output factor. Based on this factor, a simple dosimetry calculation method has been developed that takes advantage of conventional dosimetry parameters, eliminating extensive dosimetry measurements. Multiple point dose measurements within a phantom confirmed the validity of the calculation method. 2001 American College of Medical Physics.
Exploration and development of the Cerro Prieto geothermal field

A multidisciplinary effort to locate, delineate, and characterize the geothermal system at Cerro Prieto field, Baja California, Mexico, began in the late 1950's. It led to the identification of an important high-temperature, liquid-dominated geothermal system which went into production in 1973. This paper summarizes and discusses the exploration and monitoring studies related to this field.
Optimal Variable-Structure Control Tracking of Spacecraft Maneuvers

An optimal control approach using variable-structure (sliding-mode) tracking for large angle spacecraft maneuvers is presented. The approach expands upon a previously derived regulation result using a quaternion parameterization for the kinematic equations of motion. This parameterization is used since it is free of singularities. The main contribution of this paper is the utilization of a simple term in the control law that produces a maneuver to the reference attitude trajectory in the shortest distance. Also, a multiplicative error quaternion between the desired and actual attitude is used to derive the control law. Sliding-mode switching surfaces are derived using an optimal-control analysis. Control laws are given using either external torque commands or reaction wheel commands. Global asymptotic stability is shown for both cases using a Lyapunov analysis. Simulation results are shown which use the new control strategy to stabilize the motion of the Microwave Anisotropy Probe spacecraft.
Testing the spatial mismatch hypothesis using inter-city variations in industrial composition

Abstract We test the spatial mismatch hypothesis exploiting inter-city variations in industrial composition to instrument for job centralization. Job centralization raises black employment rates relative to whites. The effects are greatest in large MAs, for young and old workers, women, and those without any college. Consistent with costly mobility within cities, job centralization raises wages in the central city relative to the suburbs. IV estimates confirm our OLS results.
3D medical volume reconstruction using web services

We address the problem of 3D medical volume reconstruction using web services. The use of proposed web services is motivated by the fact that the problem of 3D medical volume reconstruction requires significant computer resources and human expertise in medical and computer science areas. Web services are implemented as an additional layer to a dataflow framework called data to knowledge. In the collaboration between UIC and NCSA, pre-processed input images at NCSA are made accessible to medical collaborators for registration. Every time UIC medical collaborators inspected images and selected corresponding features for registration, the web service at NCSA is contacted and the registration processing query is executed using the image to knowledge library of registration methods. Co-registered frames are returned for verification by medical collaborators in a new window. In this paper, we present 3D volume reconstruction problem requirements and the architecture of the developed prototype system at http://isda.ncsa.uiuc.edu/MedVolume. We also explain the tradeoffs of our system design and provide experimental data to support our system implementation. The prototype system has been used for multiple 3D volume reconstructions of blood vessels and vasculogenic mimicry patterns in histological sections of uveal melanoma studied by fluorescent confocal laser scanning microscope.
Statistical Analysis of Econometric Models

Abstract In this article, a summary of some research bearing on the statistical analysis of econometric models is reviewed. Many estimation, testing, and prediction techniques used in econometrics have just large-sample justifications. Selected Bayesian inference results relating to econometric models are reviewed. On the problem of constructing econometric models, an approach that is a blend of traditional econometric and modern time series analysis techniques is described. Many statistical problems requiring further analysis are noted. It is concluded that better solutions to these problems, better data, more sophisticated use of economic theory, application of more rigorous diagnostic checks, including forecasting checks and use of well-designed simulation experiments, probably will produce improved macroeconometric models.
Continuous-Thread Model of Load Distribution and Nut Wear in Grease-Lubricated Lead Screws

Even under constant operating conditions, greases lubricating lead screw assemblies, as well as materials comprising their nut and screw threads, must perform over a range of contact pressures that not only varies from thread to thread but also evolves with the sliding distance as most heavily loaded threads wear most rapidly. An example modeled here, consisting of a nut whose bulk body is rigid and an elastic screw body having continuous elastic meshed threads, reveals the broad distribution of load along the length of the nut threads in an unworn lead screw assembly, as well as the distribution of wear depth that must accompany an eventual steady-state of uniform rate of nut thread wear. Thread load redistributions brought on by changes in operating conditions such as applied load, or even temperature in the case of a nut/screw pair of dissimilar materials, are similarly modeled. Such load redistributions in worn lead screws may cause either the top or the bottom positions of the nut thread to become mo...
A Comparative Study of Distributed Resource Sharing on Multiprocessors

In this paper we have studied the interconnection of resources to multiprocessors and the distributed scheduling of these resources. For a given interconnection network, the resource-mapping problem entails the search of one of the free resources which can be connected to each requesting processor. To prevent the bottleneck of sequential scheduling, a request without any destination address is given to the network, and the network is responsible for finding the necessary resource and connecting it to the processor. The addressing mechanism is thus distributed in the network. Three different classes of networks have been investigated: namely, single shared bus, multiple shared buses, and multistage dynamic networks. In each case, the scheduling algorithm is described, and the tradeoffs of different network configurations are studied. The resource-sharing networks are a generalization of conventional interconnection networks with routing tags in which all the resources are of different types.
Network coding-aware queue management for TCP flows over coded wireless networks

In this paper, we are interested in improving the performance of TCP flows over wireless networks with a given constructive intersession network coding scheme. We are motivated by the observation that TCP does not fully exploit the potential of the underlying network coding opportunities. In order to improve the performance of TCP flows over coded wireless networks, without introducing changes to TCP itself, we propose a network-coding aware queue management scheme (NCAQM) that is implemented at intermediate network coding nodes and bridges the gap between network coding and TCP rate control. The design of NCAQM is grounded on the network utility maximization (NUM) framework and includes the following mechanisms. NCAQM: 1) stores coded packets at intermediate nodes in order to use the buffer space more efficiently; 2) determines what fraction of the flows should be coded together; and 3) drops packets at intermediate nodes so that it matches the rates of parts of different TCP flows that are coded together. We demonstrate, via simulation, that NCAQM significantly improves TCP throughput compared to TCP over baseline queue management schemes.
Free-Free Radiation from Dense Interstellar Shock Waves

We present detailed calculations of the free-free emission behind shock waves in media where the postshock gas may be optically thick at radio frequencies. Using a numerical shock code, we solve the free-free radiative transfer equation at frequencies of 1.5, 5, and 15 GHz for a family of planar shock models that cover a wide range of densities (1000 cm-3 ≤ n0 ≤ 109 cm-3) and shock velocities (30 km s-1 ≤ V0 ≤ 300 km s-1). These models also predict how different preshock magnetic fields and viewing angles affect the overall free-free emission. As the shock velocities and preshock densities increase, the free-free spectral indices generally rise from optically thin values (~-0.1) and approach optically thick ones (~2.0). We find that for V ≥ 120 km s-1, the ionized precursor produced by the emergent postshock UV radiation can itself become optically thick to free-free radiation when the preshock density exceeds 106 cm-3. We also find that for some combinations of shock parameters, the superposition of radiation from the precursor onto that of the postshock region can produce spectral indices exceeding 2.0. In addition, we find that magnetic fields can suppress the free-free radiation only if they are strong enough to lower the magnetosonic Mach number below 4 for V ≥ 100 km s-1. An observer who knows the resolved angular sizes, fluxes, and spectral indices of a thermal radio source can use our grids to determine the preshock density, shock velocity, and viewing angle to the source. Possible applications include HH objects, shocked cloudlets, and accretion shocks deep within molecular clouds. As an example, we use our results to predict shock parameters for HH 1-2 and several thermal radio sources in Cep A east. We find that the predicted shock parameters for HH 1 and 2 agree well with those inferred from optical line ratios and line profiles. Radio emission from sources in Cep A are explained reasonably well as arising from thermal radiation behind a dense, fast shock like one might expect from a stellar jet deeply embedded within the molecular cloud core.
The Expanded Very Large Array: A New Telescope for New Science

Since its commissioning in 1980, the Very Large Array (VLA) has consistently demonstrated its scientific productivity. However, its fundamental capabilities have changed little since 1980, particularly in the key areas of sensitivity, frequency coverage, and velocity resolution. These limitations have been addressed by a major upgrade of the array, which began in 2001 and will be completed at the end of 2012. When completed, the Expanded VLA?the EVLA?will provide complete frequency coverage from 1 to 50?GHz, a continuum sensitivity of typically 1 ?Jy beam?1 (in 9 hr with full bandwidth), and a modern correlator with vastly greater capabilities and flexibility than the VLA's. In this Letter, we describe the goals of the EVLA project, its current status, and the anticipated expansion of capabilities over the next few years. User access to the array through the Open Shared Risk Observing and Resident Shared Risk Observing programs is described. The following papers in this special issue, derived from observations in its early science period, demonstrate the astonishing breadth of this most flexible and powerful general-purpose telescope.
The 492 GHz Atmospheric Opacity at the Geographic South Pole

We present narrow-bandwidth submillimeter-wave sky opacity measurements made from the South Pole between 1995 February 9 and November 17, a period that includes an entire Austral winter. These measurements were made with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) using a heterodyne receiver tuned to a band that includes the 492 GHz fine-structure line of neutral atomic carbon. The zenith optical depth was below 0.72 half the time during the Austral winter and spring, and it reached values as low as 0.34 on day 232. The stability was also remarkably good: the opacity remained below 1.0 for weeks at a time. The South Pole is therefore an excellent site for submillimeter astronomy throughout the Austral winter and spring. The functional relationship between 492 GHz opacity and measured precipitable water vapor shows that a significant fraction of the opacity is caused by atmospheric constituents other than water vapor, indicating the need for accurate, site-dependent atmospheric modeling when opacity measurements at lower frequencies are extrapolated into the submillimeter.
The cultural influence model: when accented natural language spoken by virtual characters matters

Advances in artificial intelligence and computer graphics digital technologies have contributed to a relative increase in realism in virtual characters. Preserving virtual characters' communicative realism, in particular, joined the ranks of the improvements in natural language technology, and animation algorithms. This paper focuses on culturally relevant paralinguistic cues in nonverbal communication. We model the effects of an English-speaking digital character with different accents on human interactants (i.e., users). Our cultural influence model proposes that paralinguistic realism, in the form of accented speech, is effective in promoting culturally congruent cognition only when it is self-relevant to users. For example, a Chinese or Middle Eastern English accent may be perceived as foreign to individuals who do not share the same ethnic cultural background with members of those cultures. However, for individuals who are familiar and affiliate with those cultures (i.e., in-group members who are bicultural), accent not only serves as a motif of shared social identity, it also primes them to adopt culturally appropriate interpretive frames that influence their decision making.
Cooperative Lewis acid/N-heterocyclic carbene catalysis

Lewis acid activation with N-heterocyclic carbene (NHC) catalysis has presented new opportunities for enantioselective reaction development. Recent findings illustrate that Lewis acids can play an important role in homoenolate annulations by: enhancement of the reactivity, reversal of the diastereo- or regioselectivity, and activation of previously inactive electrophiles. Additionally, the incorporation of a Lewis acid into Bronsted base-catalyzed conjugate addition allowed for an increase in yields.
Direct neutrino mass measurements after PLANCK

Abstract The absolute mass scale of neutrinos remains an open question subject to experimental investigation from both particle physics and cosmology. Over the next decade, a number of experiments from both disciplines will attempt to probe the mass scale further to the very limits of the predictions from oscillation results. This paper provides a broad overview of the experimental program in neutrino mass scale measurements, with a particular focus on direct experimental probes due to come online over the next decade.
Audit firm tenure, non-audit services and internal assessments of audit quality

We use data from internal assessments of audit quality in a Big 4 firm to investigate the impact of audit firm tenure and auditor-provided non-audit services (NAS) on audit quality. We find that first-year audits receive lower assessments of audit quality and that quality improves shortly thereafter and then declines as tenure becomes very long. Partitioning our sample between SEC registrants and private clients, we find that the decline in audit quality in the long tenure range is attributable to audits of private clients. For audits of SEC registrants, the probability of a high quality audit reaches its maximum with very long tenure. We also find that audit fees are discounted for first-year audits but auditor effort is higher than in subsequent years. We find no association, on average, between total NAS fees and audit quality in the full sample but observe that total NAS fees are positively associated with quality for SEC registrants and negatively associated with quality for privately held clients. Our findings are important for regulatory policies related to audit firm tenure and auditor-provided NAS.
Generalized Traveling Waves in Disordered Media: Existence, Uniqueness, and Stability

We prove existence, uniqueness, and stability of transition fronts (generalized traveling waves) for reaction-diffusion equations in cylindrical domains with general inhomogeneous ignition reactions. We also show uniform convergence of solutions with exponentially decaying initial data to time translations of the front. In the case of stationary ergodic reactions, the fronts are proved to propagate with a deterministic positive speed. Our results extend to reaction-advection-diffusion equations with periodic advection and diffusion.
Numerical Simulation of Direct Metal Laser Sintering of Single-Component Powder on Top of Sintered Layers

A three-dimensional model describing melting and resolidification of direct metal laser sintering of loose powders on top of sintered layers with a moving Gaussian laser beam is developed. Natural convection in the liquid pool driven by buoyancy and Marangoni effects is taken into account. A temperature transforming model is employed to model melting and resolidification in the laser sintering process. The continuity, momentum, and energy equations are solved using a finite volume method. The effects of dominant processing parameters including number of the existing sintered layers underneath, laser scanning velocity, and initial porosity on the sintering process are investigated.
Social media and our misconceptions of the realities

This article will review the current laws of the expectations of privacy under the two-pronged Katz test, and more specifically other cases that the courts have tried to interpret the test as applicable to social media such as Facebook, Instagram, Twitter, and email. Since there seems to be ‘no light at the end of the tunnel’ with any uniform decision within the courts on the Fourth Amendment protections against search and seizure when there is a reasonable expectation of privacy with social media. This reasonable expectation standard is developed by the users themselves who will allow their rights to be infringed upon for the approval to access sites like Facebook, Twitter, and Instagram.
Tsuji–Trost N‐Allylation with Allylic Acetates by Using a Cellulose–Palladium Catalyst

Allylic amines were synthesized by a simple procedure using a biodegradable and easily recyclable heterogeneous cellulose–Pd catalyst through N-allylation of primary and secondary amines. The scope of this protocol includes aliphatic and benzylamines with substituted and unsubstituted allyl acetates and culminates in high yield syntheses. The highlights of the protocol include a ligand-free reaction, simple workup, and catalyst recyclability.
Low serum selenium is associated with anemia among older adults in the United States

We hypothesized that low serum selenium was associated with anemia in humans. A total of 2092 adults aged 65 and older, in the third National Nutrition Examination Survey, Phase 2 (1991–1994) (NHANES III). Examination of the relationship between serum selenium and hematological indices in NHANES III. Anemia, defined by World Health Organization criteria, was present in 12.9%. Mean serum selenium among non-anemic and anemic adults was 1.60 and 1.51 μmol l−1 (P=0.0003). The prevalence of anemia among adults in the lowest to highest quartiles of serum selenium was 18.3, 9.5, 9.7 and 6.9%, respectively (P=0.0005). The proportion of adults in the lowest quartile of selenium among those who were non-anemic or who had anemia due to nutritional causes, chronic inflammation, renal disease or unexplained anemia was 9.9, 27.5, 17.5, 24.0 and 15.4%, respectively. An increase in loge selenium was associated with a reduced risk of anemia (odds ratio per one standard deviation increase 0.75, 95% confidence interval 0.58–0.97, P=0.03), adjusting for age, race, education, body mass index and chronic diseases. Low serum selenium is independently associated with anemia among older men and women in the United States.
How Do Z and Atoll X-Ray Binaries Differ?

Low-mass X-ray binaries containing weakly magnetized neutron stars may be divided into two classes, Z and atoll sources, based upon correlations between their X-ray timing properties and the patterns that they trace in plots of two X-ray colors. In this Letter we examine color-color diagrams of eight atoll sources and four Z sources using data from the Rossi X-Ray Timing Explorer. The 5 year span of data we have examined is significantly longer than the spans of previous studies. We find that the previous clear distinction between color-color diagrams from atoll and Z sources is an artifact of incomplete sampling, as those atoll sources that are sampled over a wide dynamic range in intensity (Fmax/Fmin 80) trace three-branched color-color patterns similar to the tracks for which Z sources are named. However, atoll sources trace this pattern over a larger range of luminosity and on much longer timescales than do Z sources and exhibit much harder spectra when they are faint, which argues against any simple unification scheme for the two classes of source.
The number of 3-SAT functions

With G k (n) denoting the number of functions of n Boolean variables definable by k-SAT formulas, we prove that G 3(n) is asymptotic to 2 n +( 3 n ). This is a strong form of the case k = 3 of a conjecture of Bollobas, Brightwell and Leader stating that for fixed k, log2 G k (n)~( k n ).
A general method of Bayesian estimation for parametric imaging of the brain

Abstract We report a general method of Bayesian estimation that uses prior measurements to improve the signal-to-noise ratio of parametric images computed from dynamic PET scanning. In our method, the ordinary weighted least squares cost function is augmented by a penalty term to yield Φ ( K , S ) = min K { ( C − f ( K ) ) T Ω C − 1 ( C − f ( K ) ) + S Φ ( K , S = 0 ) ( K − K ^ ) T Ω K − 1 ( K − K ^ ) } , where C is a PET concentration history and Ω C is its variance, f is the model of the concentration history, K = [ k 1 , k 2 ,…, k m ] T is the parameter vector, K ^ is the vector of population means for the model parameters, Ω K is its covariance, Φ K ( K , S = 0) is the conventional weighted sum of squares. S > 0 is chosen to control the balance between the prior and new data. Data from a prior population of subjects are analyzed with standard methods to provide maps of the mean parameter values and their variances. As an example of this approach we used the dynamic image data of 10 normal subjects who had previously been studied with 11 C-raclopride to estimate the prior distribution. The dynamic data were transformed to stereotactic coordinates and analyzed by standard methods. The resulting parametric maps were used to compute the voxel-wise sample statistics. Then the cohort of priors was analyzed as a function of S , using nonlinear least squares estimation and the cost function shown above. As S is increased the standard error in estimating BP in single subjects was substantially reduced allowing measurement in BP in thalamus, cortex, brain stem, etc. Additional studies demonstrate that a range of S values exist for which the bias is not excessive, even when parameter values differ markedly from the sample mean. This method can be used with any kinetic model so long as it is possible to compute a map of a priori mean parameters and their variances.
Effect of Higher Stress Harmonics and Spectral Width on Fatigue Damage of Marine Risers

Recently, experimental data from vortex induced vibrations (VIV) of long flexible cylinders have revealed the existence of (i) higher harmonic stress components, and (ii) chaotic response characteristics, in addition to the well-known first harmonic responses. To assess the effect of these phenomena on fatigue damage of long flexible structures, we generate alternative stress time series, with and then without higher harmonic components; as well as time series, which have either sharply peaked power spectral densities (PSD), or broad-banded PSDs, characteristic of chaotic response. We show that for stresses containing higher harmonics, the predicted fatigue damage to the riser can increase by a factor of 2.5 relative to the damage caused by stresses containing only the first harmonic and having equivalent total power. Likewise, for stresses with a significantly spread PSD, an indicator of chaotic response, the damage to the riser is increased by a factor of 1.8, relative to a stress with narrow-band PSD and the same total power. Thus, it is found that the increase in fatigue damage caused by chaotic response can be as significant as that caused by the stress higher harmonic components.Copyright © 2011 by ASME
New Optimal Cycle Length Formulation for Pretimed Signals at Isolated Intersections

Under near-saturated or saturated conditions, the optimal cycle length formulation proposed by Webster becomes infeasible because (1) it generates an unreasonably large cycle length as the intersection critical flow ratio approaches one, and (2) it becomes inapplicable if the intersection critical flow ratio is equal to or greater than one. An attempt is made here to rectify this deficiency by providing a simplistic but reasonably accurate formulation for optimal cycle length under saturated conditions. Using the optimal timing variables obtained based on the delay minimization criterion, the functional relationship between optimal cycle lengths and traffic flow parameters, including intersection critical flow ratio, total lost time, and duration of analysis period, is established through a nonlinear regression analysis. The resulting formulation generates fairly accurate estimates of optimal cycle length with 5.7% average deviation from the analytical solutions. The corresponding average delay, however, only deteriorates about 0.9%. The timing plans consisting of the proposed optimal cycle estimates and the equalized degree-of-saturation green splits produce near-optimal delay performance with 3.3% degradation from the optimal solutions.