cssi/SciSciGPT-SciSciNet huggingface dataset:
ROTATIONAL STABILIZATION OF MAGNETICALLY COLLIMATED JETS

We investigate the launching and stability of extragalactic jets through nonlinear magnetohydrodynamic (MHD) simulation and linear eigenmode analysis. In the simulations of jet evolution, a small-scale equilibrium magnetic arcade is twisted by a differentially rotating accretion disk. These simulations produce a collimated outflow which is unstable to the current driven m = 1 kink mode for low rotational velocities of the accretion disk relative to the Alfven speed of the coronal plasma. The growth rate of the kink mode in the jet is shown to be inversely related to the rotation rate of the disk, and the jet is stable for high rotation rates. Linear MHD calculations investigate the effect of rigid rotation on the kink mode in a cylindrical plasma. These calculations show that the Coriolis force distorts the m = 1 kink eigenmode and stabilizes it at rotation frequencies such that the rotation period is longer than a few Alfven times.
Three scales of professional deviance within organizations

Salaried professionals may exhibit organizational deviance when faced with conflict resulting from their mutual role as professional and employee. Some of this behavior may be directly harmful to both the individual and the organization, whereas some may constitute adaptive maladjustments. An earlier study proposed that these deviant behaviors could be organized into Guttman scales. In this article, three such scales were tested for underlying unidimensionality and cumulativeness using scalogram analysis. Not only was the practice of organizational deviance, although not widespread, confirmed, but the scales survived the parameters of the Guttman procedure. A replication of the scales produced sufficient validation for their further development and usage.
Economic Growth and the Rise of Forests

Although forests have diminished globally over the past 400 years, forest cover has increased in some areas, including India in the last two decades. Aggregate time-series evidence on forest growth rates and income growth across countries and within India and a newly assembled data set that combines national household survey data, census data, and satellite images of land use in rural India at the village level over a 29-year period are used to explore the hypothesis that increases in the demand for forest products associated with income and population growth lead to forest growth. The evidence is consistent with this hypothesis, which also shows that neither the expansion of agricultural productivity nor rising wages in India increased local forest cover.
Collisions of Free-floating Planets with Evolved Stars in Globular Clusters

We estimate the rate of collisions between stars and free-floating planets (FFPs) in globular clusters, in particular, the collision of FFPs with red giant branch (RGB) stars. Recent dynamical simulations imply that the density of such objects could exceed ~106 pc-3 near the cores of rich globular clusters. We show that in these clusters ~5%-10% of all RGB stars near the core would suffer a collision with an FFP and that such a collision can spin up the RGB star's envelope by an order of magnitude. In turn, the higher rotation rates may lead to enhanced mass-loss rates on the RGB, which could result in bluer horizontal branch (HB) stars. Hence, it is plausible that the presence of a large population of FFPs in a globular cluster can influence the distribution of stars on the HB of that cluster to a detectable degree.
A cospectral analysis of exchange rate comovements during Asian financial crisis

Abstract Comovements of exchange rates before and during Asian financial crisis are examined using cross-spectral methodology. The paper proposes and implements a simple frequency-domain-based test for contagion that avoids biases of the correlation breakdown tests used in the extant literature. The Asian crisis is found to be manifest in greater comovements along high-frequency components. Calculated changes in the high-frequency portion of the covariance indicate a contagion for 48 out of the possible 66 pairs of countries in the sample.
The Total Ionization Produced in Air by Electrons of Various Energies

Range in air and total ionization by electrons of energy up to 2225 volts.---Electrons from a tungsten filament were accelerated to a cylindrical anode with a small axial hole through which a fraction passed into a hemispherical ionization chamber maintained at a definite pressure by means of an adjustable leak, while the filament chamber was connected to a diffusion pump. The number of electrons entering the ionization chamber and the number of positive ions formed by them was measured with an electrometer. From ionization-pressure curves the range of electrons of various energies was determined, and was found to obey the fourth-power velocity law $R\ensuremath{\propto}{v}^{4}$, or $\sqrt{R}=\frac{V}{15900}$, where $V$ is the energy in equivalent volts and $R$ is in cm at atmospheric pressure. The total ionization curve begins at 17 volts, and rises with minor peaks at 127, 250, 375 and 494 volts of 1.83, 2.70, 4.10 and 5.05 ions per electron, to 43.2 ions per electron at 1000 volts; then the increase is approximately linear to 55 ions per electron at 2225 volts, and the values of others for high speed electrons indicate that this increase continues at about the same rate. These results tend to confirm Bohr's theory of ionization as corrected by Fowler. The voltages at which the total ionization shows peaks are interpreted as the ionization potentials of the L-electrons of argon (250) and the K-electrons of nitrogen (375) and of oxygen (494). The ionization per cm of path at 1 mm pressure, obtained by di viding the total ionization by the range, reaches a maximum of 112 ions/cm for 40 volts and a second maximum of 13.9 ions/cm for 987 volts. The first maximum agrees with that predicted from the ionization potentials of the molecule and atom of nitrogen, and the second corresponds to twice the ionization potential for the K-electrons of oxygen and gives a value of 22.8 volts energy per ion pair produced, in agreement with theory. For electrons with 40 volts energy, Bohr's theory gives the maximum effective radius of air molecules during collision as approximately 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ cm. The 987 volt electrons are probably those which give the "sphere" tracks in C. T. R. Wilson's photographs. Their range is.04 mm at atmospheric pressure.
Chemoselective Arylamidine Cyclizations: Mild Formation of 2-Arylimidazole-4-carboxylic Acids

A versatile, one-pot synthesis of 2-arylimidazole-4-carboxylic acids from arylamidines and methyl-2-chloroacetoacetate is described. The transformation is chemoselective, and reaction conditions are mild. Moreover, the flexibility of the strategy offers rapid access to two important classes of biaryl compounds, both 2-arylimidazoles and 2-arylpyrimidines, depending simply upon solvent and base selection.
The evolution of photospheric magnetic structures in terms of the size-flux relationship

We find that the dark regions of pores and spots (which include their penumbrae) have a nearly universal average flux density of 800±32 G while normal contrast azimuth centers (ACs) and pore sheaths, i.e., the associated magnetic envelopes about the dark regions, also show a similar constancy but at 334±22 G, and spot sheaths are characterized by 107±22 G. Using these flux density values and the observed dark and magnetic (dark+sheath) radii, we derive a magnetic flux-dark flux relation that yields radius-flux relations for pores and spots. The magnetic radius versus flux relation for spots is distinct, with larger radii at one and the same flux than those for pores, while the curve for the dark radius is continuous with that for pores. Spots differ from pores only in the nature of their sheaths. The AC structure, a "pure" sheath, has a radius-flux relation different from, but bridging, those of pores and spots. We suggest these relations to be universal. The temporal magnetic evolution for two developing pores and a decaying spot in the radius-flux plane traces the universal dark radius curve for both types of features. The evolution of an AC into a pore, perhaps via a bifurcation, follows the universal curves for dark and magnetic radii. Any bifurcation in the transition from a pore to a spot must appear via a transition in the magnetic sheath.
Unified Engineering: A Twenty Year Experiment in Sophomore Aerospace Education at MIT

Unified Engineering is the two-semester subject teaching the aerospace sophomore core curriculum at MIT. It contains material from four traditional single semester, single discipline courses. The paper summarizes the history of the course and presents its current structure including the teaching staff involved, textbooks used, and the overall organization. Some of Unified's unique features are the identification of linkages between disciplines, the encouragement of teamwork, emphasis on real-world engineering, and support for the department's implicit curriculum. Students perceive Unified as a course that imposes a high workload, teaches them a very large amount of material, and encourages strong bonds with their classmates in the department. The interaction of senior faculty, junior faculty, graduate teaching fellows, and undergraduate teaching assistants, all in one course, provides educational benefits for the entire teaching staff.
Capacity of Channels With Action-Dependent States

We consider channels with action-dependent states: Given the message to be communicated, the transmitter chooses an action sequence that affects the formation of the channel states, and then creates the channel input sequence based on the state sequence. We characterize the capacity of such a channel both for the case where the channel inputs are allowed to depend noncausally on the state sequence and the case where they are restricted to causal dependence. Our setting covers previously considered scenarios involving transmission over channels with states known at the encoder, as well as various new coding scenarios for channels with a “rewrite” option that may arise naturally in storage for computer memories with defects or in magnetic recoding. A few examples are worked out in detail.
Understanding the Practical Limits of the Gnutella P2P System : An Analysis of Query Terms and Object Name Distributions

A number of prior efforts analyzed the behavior of popular peer-to-peer (P2P) systems and proposed ways for maintaining the overlays as well as methods for searching for contents using these overlays. However, little was known about how successful users could be in locating the shared objects in these system. There might be a mismatch between the way content creators named objects and the way such objects were queried by the consumers. Our aim was to examine the terms used in the queries and shared object names in the Gnutella file-sharing system. We analyzed the object names of over 20 million objects collected from 40,000 peers as well as terms from over 230,000 queries. We observed that almost half (44.4%) of the queries had no matching objects in the system regardless of the overlay or search mechanism used to locate the objects. We also evaluated the query success rates against random peer groups of various sizes (200, 1K, 2K, 3K, 4K, 5K, 10K and 20K peers sampled from the full 40,000 peers). We showed that the success rates increased rapidly from 200 to 5,000 peers, but only exhibited modest improvements when increasing the number of peers beyond 5,000. Finally, we observed Zipf-like distribution for query terms and the object names. However, the relative popularity of a term in the object names did not correlate with the terms popularity in the query workload. This observation affected the ability of hybrid P2P systems to guide searches by creating a synopsis of the peer object names. A synopsis created by using the distribution of terms in the object names need not represent relevant terms for the query. Our results can be used to guide the design of future P2P systems that are optimized for the observed object names and user query behavior.
The Application of Command Shaping to the Tracking Problem

This work presents a novel technique for the solution of an optimal input for trajectory tracking. Many researchers have documented the performance advantages of command shaping, which focuses on the design of an optimal input. Nearly all research in command shaping has been centered on the point-to-point motion control problem. However, tracking problems are also an important application of control theory. The proposed optimal tracking technique extends the point-to-point motion control problem to the solution of the tracking problem. Thus, two very different problems are brought into one solution scheme. The technique uses tolerances on trajectory following to meet constraints and minimize either maneuver time or input energy. A major advantage of the technique is that hard physical constraints such as acceleration or allowable tracking error can be directly constrained. Previous methods to perform such a task involved using various weightings that lack physical meaning. The optimal tracking technique allows for fast and efficient exploration of the solution space for motion control. A solution verification technique is presented and some examples are included to demonstrate the technique.
The rate of multi-step evolution in Moran and Wright-Fisher populations.

Abstract Several groups have recently modeled evolutionary transitions from an ancestral allele to a beneficial allele separated by one or more intervening mutants. The beneficial allele can become fixed if a succession of intermediate mutants are fixed or alternatively if successive mutants arise while the previous intermediate mutant is still segregating. This latter process has been termed stochastic tunneling. Previous work has focused on the Moran model of population genetics. I use elementary methods of analyzing stochastic processes to derive the probability of tunneling in the limit of large population size for both Moran and Wright–Fisher populations. I also show how to efficiently obtain numerical results for finite populations. These results show that the probability of stochastic tunneling is twice as large under the Wright–Fisher model as it is under the Moran model.
Further evidence on corporate bonds with event-risk covenants: Inferences from Standard and Poor's and Moody's bond ratings

Abstract This study considers potential differences in the appraisal of event-risk covenants by the two rating agencies, SP the difference, however, is not statistically significant. Regression analysis shows that the S&P event-risk rankings are significantly, positively related to bond yield spreads, indicating that the market values event-risk covenants and that greater yield spreads are associated with lower event-risk protection. Regression analysis further shows that the event-risk rankings in a regression model, in conjunction with the Moody's bond ratings, are also significantly related to bond yield spreads. Overall, the results indicate that the market views the event-risk covenants as important, but that Moody's does not perceive these covenants to be strong enough to provide a rationale to upgrade its bond ratings. This evidence is consistent with the observation that the majority of event-risk covenants, as ranked by S&P, provide weak or little protection to bondholders.
Twist Relation, Third Factorization, and the General Vertex in a Dual Multiparticle Theory with Nonlinear Trajectories

The following properties of the dual multiparticle theory with nonlinear trajectories are presented: (I) the twist relation, (II) the unsymmetric general vertex obtained directly from third factorization, and (III) the symmetric general vertex.
COSMIC RAY ORIGIN IN OB ASSOCIATIONS AND PREFERENTIAL ACCELERATION OF REFRACTORY ELEMENTS: EVIDENCE FROM ABUNDANCES OF ELEMENTS 26Fe THROUGH 34Se

We report abundances of elements from _(26)Fe to _(34)Se in the cosmic radiation measured during fifty days of exposure of the Trans-Iron Galactic Element Recorder (TIGER) balloon-borne instrument. These observations add support to the concept that the bulk of cosmic ray acceleration takes place in OB associations, and they further support cosmic ray acceleration models in which elements present in interstellar grains are accelerated preferentially compared with those found in interstellar gas.
Asymmetric synthesis of oxazolidine nucleosides and related chemistry.

Abstract Asymmetric synthesis of N-substituted oxazolidinyl nucleosides has been accomplished from L-isoserine. trans- and cis-Oxazolidine intermediates (4 and 5) were stereoselectively constructed from N-protected L-isoserine with a menthoxycarbonyl group by the condensation with benzoyloxy acetaldehyde dimethyl acetal in a ratio of 3.9 to 1 in favor of trans-isomer 4. The major isomer 4 was converted to enantiomerically pure β-and α- N-L-menthoxycarbonyl oxazolidinyl thymine nucleosides 11 and 12 in 6 steps.
Self-assembly of Janus Ellipsoids

We propose a primitive model of Janus ellipsoids that represents particles with an ellipsoidal core and two semisurfaces coded with dissimilar properties, for example, hydrophobicity and hydrophilicity, respectively. We investigate the effects of the aspect ratio on the self-assembly morphology and aggregation processes using Monte Carlo simulations. We also discuss certain differences between our results and those of earlier results for Janus spheres. In particular, we find that the size and structure of the aggregate can be controlled by the aspect ratio.
Three-Body Kick to a Bright Quasar Out of Its Galaxy during a Merger

The quasar HE 0450-2958 was recently discovered to reside ~7 kpc away from a galaxy that was likely disturbed by a recent merger. The lack of a massive spheroid of stars around the quasar raised the unlikely suggestion that it may have formed in a dark galaxy. Here we explain this discovery as a natural consequence of a dynamical kick imparted to the quasar as it interacted with a binary black hole system during a galaxy merger event. The typical binary stalling radius provides a kick on the order of the escape velocity of the stellar spheroid, bringing the quasar out to around the observed radius before it reverses direction. This is consistent with the observed low relative velocity between the quasar and the merger-remnant galaxy. The gas carried with the black hole throughout the three-body interaction fuels the quasar for the duration of its journey, ~2 × 107 years. Gravitational radiation recoil could not have produced the required kick.
Bayesian estimation of the shape skeleton

Skeletal representations of shape have attracted enormous interest ever since their introduction by Blum [Blum H (1973) J Theor Biol 38:205-287], because of their potential to provide a compact, but meaningful, shape representation, suitable for both neural modeling and computational applications. But effective computation of the shape skeleton remains a notorious unsolved problem; existing approaches are extremely sensitive to noise and give counterintuitive results with simple shapes. In conventional approaches, the skeleton is defined by a geometric construction and computed by a deterministic procedure. We introduce a Bayesian probabilistic approach, in which a shape is assumed to have "grown" from a skeleton by a stochastic generative process. Bayesian estimation is used to identify the skeleton most likely to have produced the shape, i.e., that best "explains" it, called the maximum a posteriori skeleton. Even with natural shapes with substantial contour noise, this approach provides a robust skeletal representation whose branches correspond to the natural parts of the shape.
Ligands of the neuropeptide Y Y2 receptor

Neuropeptide Y (NPY) is one of the most abundant neuropeptides in the mammalian brain and exerts a variety of physiological processes in humans via four different receptor subtypes Y1, Y2, Y4 and Y5. Y2 receptor is the most abundant Y subtype receptor in the central nervous system and implicated with food intake, bone formation, affective disorders, alcohol and drugs of abuse, epilepsy, pain, and cancer. The lack of small molecule non-peptidic Y2 receptor modulators suitable as in vivo pharmacological tools hampered the progress to uncover the precise pharmacological role of Y2. Only in recent years, several potent, selective and non-peptidic Y2 antagonists have been discovered providing the tools to validate Y2 receptor as a therapeutic target. This Letter reviews Y2 receptor modulators mainly non-peptidic antagonists and their structure-activity relationships.
Close or positive margins after surgical resection for the head and neck cancer patient: The addition of brachytherapy improves local control☆

Purpose: Microscopically positive or close margins after surgical resection results in an approximately 21-26% local failure rate despite excellent postoperative external radiation therapy. We sought to demonstrate improved local control in head and neck cancer patients who had a resection with curative intent, and had unexpected, microscopically positive or close surgical margins. Methods and Materials: Twenty-nine patients with microscopically close or positive margins after curative surgery were given definitive, adjuvant external radiation therapy and 125 I brachytherapy. All 29 patients had squamous cell cancer and tonsil was the most common subsite within the head and neck region. After external radiation therapy and thorough discussions with the attending surgeon and pathologists, the slides, gross specimens, and appropriate radiographs were reviewed and a target volume was determined. The target volume was the region of the margin in question and varied in size based on the surgery and pathologic results. Once the target volume was identified the patient was taken back to the operating room for insertion of 125 I seeds. Activity implanted (range 2.9-21.5 millicuries) was designed to administer a cumulative lifetime dose of 120-160 Gy. Results: Twenty-nine patients were followed for a median of 26 months (range 5-86 months). Two-year actuarial local control was 92%. Conclusion: 125 I, after external radiation therapy, is an excellent method to improve local control in the subset of patients with unexpectedly unsatisfactory margins.
Topological theory of electron-phonon interactions in high-temperature superconductors

There are large isotope effects in the phonon kinks observed in angle-resolved photoemission spectroscopy of optimally doped cuprate high-temperature superconductors (HTSC), but they are quite different from those expected for a nearly free-electron metal (Fermi liquid) with strong electron-phonon interactions (Eliashberg model). These differences, together with many other anomalies in infrared spectra, seem to suggest that other particles (such as magnons) must be contributing to HTSC. Here we use topological methods to discuss the data, emphasizing nanoscale phase separation and the importance of a narrow band of quantum percolative states near the Fermi energy that is spatially pinned to a self-organized filamentary dopant array, resulting in a filamentary glass. Topological discrete, noncontinuum, nonperturbative methods have previously explained the form of HTSC phase diagrams without involving detailed microscopic assumptions, and they are especially useful in the presence of strong nanoscale glassy disorder. These methods also explain the ``miracle'' of an ideal nearly free-electron (gas or liquid) phonon kink in sharply defined nodal quasiparticle states in LSCO at the metal-insulator transition. Careful study of the data reveals anharmonic phonon interactions. Finally, the universality of the kink energy and Fermi velocities below the Debye cutoff in different cuprates is the result of the marginally elastic nature of these configurationally glassy materials, and specifically the isostatic character of the ${\mathrm{CuO}}_{2}$ planes.
Tholins - Organic chemistry of interstellar grains and gas

The paper discusses tholins, defined as complex organic solids formed by the interaction of energy - for example, UV light or spark discharge - with various mixtures of cosmically abundant gases - CH4, C2H6, NH3, H2O, HCHO, and H2S. It is suggested that tholins occur in the interstellar medium and are responsible for some of the properties of the interstellar grains and gas. Additional occurrences of tholins are considered. Tholins have been produced experimentally; 50 or so pyrolytic fragments of the brown, sometimes sticky substances have been identified by gas chromatography-mass spectrometry, and the incidence of these fragments in tholins produced by different procedures is reported.
Inhalation exposure model for volatile chemicals from indoor uses of water

Abstract An indoor air quality model, MAVRIQ, has been developed for use with a personal computer (PC) to simulate the air concentration of organic compounds due to volatilization of chemicals originating in the domestic water supply. MAVRIQ also simulates the inhalation exposure of individuals based on their location and water use behavior. An application of MAVRIQ, presented in this paper, demonstrates the effect of various water uses on the air concentrations in a test house, and on the inhalation exposure of the inhabitants. The occupants' activities, location and water-use patterns are shown to affect their inhalation exposure. In the case of a person who spends the majority of his or her time in a home (such as the primary child-care adult) with contaminated water supply, the daily inhalation exposure is likely to exceed the exposure from ingestion of the same water. A large part of the inhalation exposure occurs during showering and post-showering activities, but other water uses also contribute. In addition, it is shown that a simple remedial action, the installation of a bathroom exhaust fan, can result in significant reductions of the inhalation exposure.
The Source Coding Game With a Cheating Switcher

The problem of finding the rate-distortion function of an arbitrarily varying source (AVS) composed of a finite number of memoryless subsources is revisited. Berger's 1971 paper “The Source Coding Game” solves this problem when the adversary is allowed only strictly causal access to the subsource realizations. The case when the adversary has access to the subsource realizations non-causally is considered. This new rate-distortion function is determined to be the maximum of the rate-distortion function over a set of independent and identically distributed (IID) random variables that can be simulated by the adversary. The results are extended to allow for partial or noisy observations of subsource realizations. The model is further explored by attempting to find the rate-distortion function when the `adversary' is actually helpful. Finally, a bound is developed on the uniform continuity of the IID rate-distortion function for finite-alphabet sources. The bound is used to give a sufficient number of distributions that need to be sampled to compute the rate-distortion function of an AVS to within a desired accuracy. The bound is also used to give a rate of convergence for the estimate of the rate-distortion function for an unknown IID source.
The Combinatorial Synthesis of Purine, Pyrimidine and Triazine‐based Libraries

With the advent of combinatorial chemistry, heterocyclic scaffolds can be efficiently used for the generation of large member libraries. Due to the pressing need for such compound libraries, unique synthesis reactions and techniques have been developed to expedite and further improve the process. Present review article summarizes synthetic strategies for the construction of purine, pyrimidine and triazine libraries in both solution and solid phase syntheses. Typical strategy includes the nucleophilc aromatic substitution, such as amination. Also, metal-mediated synthesis has been used as a driving tool in expanding the diversity of the libraries. Demonstrated biological properties of these libraries, as a rich source of bioactivities, are also highlighted.
Single stock futures: Listing selection and trading volume

Abstract On November 8, 2002, two new exchanges, OneChicago and NQLX, began trading single stock futures (SSFs). We study how these exchanges choose the listed products. The selection process is consistent with the objective of maximizing the market opening success. The estimated probability of listing is a good predictor of the single stock futures' post-listing success, as measured by their trading volume in the first year.
An alternative interpretation for the Holm alpha model

By reinterpreting a recent successful closure procedure in terms of local spatial averaging and the neglect of fluctuations about that average, it is shown how the results of that closure scheme (the “alpha model”) may be more simply derived.
Conditions that guarantee no overshoot for linear systems

In practical control problems it is often desirable to make setpoint changes without overshoot. In this paper necessary and sufficient conditions are presented which guarantee that linear state-space models will not exhibit overshoot. Several examples illustrate the utility and simplicity of the new results
Electromagnetic modeling of three‐dimensional bodies in layered earths using integral equations

We have developed an algorithm based on the method of integral equations to simulate the electromagnetic responses of three‐dimensional bodies in layered earths. The inhomogeneities are replaced by an equivalent current distribution which is approximated by pulse basis functions. A matrix equation is constructed using the electric tensor Green’s function appropriate to a layered earth, and it is solved for the vector current in each cell. Subsequently, scattered fields are found by integrating electric and magnetic tensor Green’s functions over the scattering currents. Efficient evaluation of the tensor Green’s functions is a major consideration in reducing computation time. We find that tabulation and interpolation of the six electric and five magnetic Hankel transforms defining the secondary Green’s functions is preferable to any direct Hankel transform calculation using linear filters. A comparison of responses over elongate three‐dimensional (3-D) bodies with responses over two‐dimensional (2-D) bodie...
Electrical tuning and switching of an optical frequency comb generated in aluminum nitride microring resonators

Aluminum nitride (AlN) has been shown to possess both strong Kerr nonlinearity and electro-optic Pockels effect. By combining these two effects, here we demonstrate on-chip reversible on/off switching of the optical frequency comb generated by an AlN microring resonator. We optimize the design of gating electrodes and the underneath resonator structure to effectively apply an electric field without increasing the optical loss. The switching of the comb is monitored by measuring one of the frequency comb peaks while varying the electric field. The controlled comb electro-optic response is investigated for direct comparison with the transient thermal effect.
Consumer opinions of a stance control knee orthosis

Stance control knee orthoses (SCOs) have become very popular recently. However, there is little information regarding opinions of actual orthosis users. The purpose of this study was to quantify the users' opinions of a SCO, and see whether factors found important for knee orthoses in past studies hold true for a stance control orthosis as well. A standardized survey was employed as part of a larger field trial study of the Dynamic Knee Brace System, a SCO developed by the authors. The Dynamic Knee Brace System scored well in areas of effectiveness, operability, and dependability, but areas in need of improvement included weight, cosmesis, and donning and doffing. These findings match well with previous knee orthosis studies. This study shows that wearing a stance control knee orthosis can be a positive experience for an orthosis user.
Electromagnetic probes at RHIC-II

Abstract We summarize how future measurements of electromagnetic (EM) probes at the Relativistic Heavy Ion Collider (RHIC), in connection with theoretical analysis, can advance our understanding of strongly interacting matter at high energy densities and temperatures. After a brief survey of the important role that EM probes data have played at the Super Proton Synchrotron (SPS, CERN) and RHIC to date, we identify key physics objectives and observables that remain to be addressed to characterize the (strongly interacting) Quark–Gluon Plasma (sQGP) and associated transition properties at RHIC. These include medium modifications of vector mesons via low-mass dileptons, a temperature measurement of the hot phases via continuum radiation, as well as γ – γ correlations to characterize early source sizes. We outline strategies to establish microscopic matter and transition properties such as the number of degrees of freedom in the sQGP, the origin of hadron masses and manifestations of chiral symmetry restoration, which will require accompanying but rather well-defined advances in theory. Increased experimental precision, an order of magnitude higher statistics than currently achievable, as well as a detailed scan of colliding species and energies are mandatory to discriminate between theoretical interpretations. This increased precision can be achieved through hardware upgrades to the large RHIC detectors (PHENIX and STAR) along with at least a factor of ten increase in luminosity over the next few years, as envisioned for RHIC-II.
On Vafa’s theorem for tensor categories

In this note we prove two main results. 1. In a rigid braided finite tensor category over C (not necessarily semisimple), some power of the Casimir element and some even power of the braiding is unipotent. 2. In a (semisimple) modular category, the twists are roots of unity dividing the algebraic integer D^{5/2}, where D is the global dimension of the category (the sum of squares of dimensions of simple objects). Both results generalize Vafa's theorem, saying that in a modular category twists are roots of unity, and square of the braiding has finite order. We also discuss the notion of the quasi-exponent of a finite rigid tensor category, which is motivated by results 1 and 2 and the paper math/0109196 of S.Gelaki and the author.
Stage ta-t1 bladder cancer: the relationship between findings at first followup cystoscopy and subsequent recurrence and progression.

Abstract Purpose: We studied the relationship of first cystoscopy findings with recurrence and progression rates in a large, population based series of patients with bladder cancer. Materials and Methods: All 463 patients with an initial diagnosis of stage Ta–T 1 bladder cancer in western Sweden in 1987 to 1988 were followed at least 5 years. The 355 patients who were treated with transurethral resection only until repeat cystoscopy or longer were selected for this report. Results: Negative first cystoscopy findings were associated with significantly decreased recurrence and progression rates for all grades, and for stage Ta and T 1 tumors. However, some patients with initial high grade carcinoma (WHO 2 to 3) had stage progression despite negative first cystoscopy. On multivariate analyses first cystoscopy findings and papillary urothelial neoplasm of low malignant potential versus grades 1 to 3 but not stage and the number of tumors had prognostic significance for time to recurrence. Only first cystoscopy findings and grade had prognostic significance for time to stage progression. Conclusions: Our data support other groups who recommend a less intense cystoscopy followup schedule in patients with negative cystoscopy findings 3 months after initial transurethral bladder resection. We recommend that patients with initial papillary urothelial neoplasm of low malignant potential and low grade carcinoma (WHO 1) with negative first cystoscopy findings undergo repeat cystoscopy at month 12. In our opinion followup should not be less intense in patients with high grade carcinoma (WHO 2–3), even in those with stage pTa disease.
Inexpensive Cross‐Linked Polymeric Separators Made from Water‐Soluble Polymers

Polyvinyl alcohol (PVA), cross-linked chemically with aldehyde reagents, produces membranes which demonstrate oxidation resistance, dimensional stability, low ionic resistivity (less than 0.8 Ohms sq cm), low zincate diffusivity (less than 1 x 10 to the -7th mols/sq cm per min), and low zinc dendrite penetration rate (greater than 350 min) which make them suitable for use as alkaline battery separators. They are intrinsically low in cost, and environmental health and safety problems associated with commercial production appear minimal. Preparation, property measurements, and cell test results in Ni/Zn and Ag/Zn cells are described and discussed.
A Theory for Predicting the Turbulent-Spot Production Rate

A theory is presented for predicting the production rate of turbulent spots. The theory, based on that by Mayle-Schulz for bypass transition, leads to a new correlation for the spot production rate in boundary layer flows with a zero pressure gradient. The correlation, which agrees reasonably well with data, clearly shows the effects of both free-stream turbulence level and length scale. In addition, the theory provides an estimate for the lowest level of free-stream turbulence causing bypass transition.
Wittig reaction of unprotected d-aldopentoses with stabilized ylides: metal-ion effects

Abstract Each of the four d -aldopentoses (1–4) reacts in the unprotected form with Ph3PCHCO2Me (5) in THF to give stereoslectively the coresponding trans-α,β-unsaturated C7 Wittig adducts, isolated as the corresponding 4,5,6,7-tetraacetates (7–10) or 4,5:6,7-di-O-isopropylidene derivatives (11–14). Concurrently formed are also bicyclic, 1,4-lactone derivatives, isolated as their 5,7-diacetates (15–18) or 5,7-O-isopropylidene derivatives (19), arising through intramolecular Michael addition from the initial acyclic adducts. Formation of the cyclized products is suppressed by incorporation of Cu(OAc)2 in the reaction mixture, permitting preparative isolation of the hept-3-enonate derivatives 7–10, useful as dienophiles in Diels-Alder carbocyclizations with chirality transfer. Optimized yields were 25% ( d -ribo), 50% ( d -arabino), 49% ( d -xylo), and 61% ( d -lyxo). Under Cu(OAc)2-catalyzed conditions, the formation of small proportions of 3,7-anhydroheptonic acid esters (21 and 23) was observed in the d -arabino and d -xylo series, but not with the other two pentoses.
A Conversation with Myles Hollander

Myles Hollander was born in Brooklyn, New York, on March 21, 1941. He graduated from Carnegie Mellon University in 1961 with a B.S. in mathematics. In the fall of 1961, he entered the Department of Statistics, Stanford University, earning his M.S. in statistics in 1962 and his Ph.D. in statistics in 1965. He joined the Department of Statistics, Florida State University in 1965 and retired on May 31, 2007, after 42 years of service. He was department chair for nine years 1978–1981, 1999–2005. He was named Professor Emeritus at Florida State upon retirement in 2007. Hollander served as Editor of the Journal of the American Statistical Association, Theory and Methods, 1994–1996, and was an Associate Editor for that journal from 1985 until he became Theory and Methods Editor-Elect in 1993. He also served on the editorial boards of the Journal of Nonparametric Statistics (1993–1997; 2003–2005) and Lifetime Data Analysis (1994–2007). Hollander has published over 100 papers on nonparametric statistics, survival analysis, reliability theory, biostatistics, probability theory, decision theory, Bayesian statistics and multivariate analysis. He is grateful for the generous research support he has received throughout his career, most notably from the Office of Naval Research, the U.S. Air Force Office of Scientific Research, and the National Institutes of Health. Myles Hollander has received numerous recognitions for his contributions to the profession. He was elected Fellow of the American Statistical Association (1972) and the Institute of Mathematical Statistics (1973), and became an elected member of the International Statistical Institute (1977). At Florida State University he was named Distinguished Researcher Professor (1996), he received the Professorial Excellence Award (1997), and in 1998 he was named the Robert O. Lawton Distinguished Professor, an award made to only one faculty member per year and the University’s highest faculty honor. Myles Hollander was the Ralph A. Bradley Lecturer at the University of Georgia in 1999, and in 2003 he received the Gottfried E. Noether Senior Scholar Award in Nonparametric Statistics from the American Statistical Association. He was the Buckingham Scholar-in-Residence at Miami University, Oxford, Ohio in September, 1985, and had sabbatical visits at Stanford University (1972–1973; 1981–1982), the University of Washington (1989–1990) and the University of California at Davis (Spring, 2006). The following conversation took place in Myles Hollander’s office at the Department of Statistics, Florida State University, Tallahassee, on April 19, 2007.
Real-Time Motion Planning for Agile Autonomous Vehicles

Planning the path of an autonomous, agile vehicle in a dynamic environment is a very complex problem, especially when the vehicle is required to use its full maneuvering capabilities. Recent efforts aimed at using randomized algorithms for planning the path of kinematic and dynamic vehicles have demonstrated considerable potential for implementation on future autonomous platforms. This paper builds upon these efforts by proposing a randomized path planning architecture for dynamical systems in the presence of fixed and moving obstacles. This architecture addresses the dynamic constraints on the vehicle's motion, and it provides at the same time a consistent decoupling between low-level control and motion planning. The path planning algorithm retains the convergence properties of its kinematic counterparts. System safety is also addressed in the face of finite computation times by analyzing the behavior of the algorithm when the available onboard computation resources are limited, and the planning must be performed in real time. The proposed algorithm can be applied to vehicles whose dynamics are described either by ordinary differential equations or by higher-level, hybrid representations. Simulation examples involving a ground robot and a small autonomous helicopter are presented and discussed.
Mathematical modelling of chemical engineering systems by finite element analysis using PDE/PROTRAN

Abstract The use of commercially available software for obtaining finite-element solutions to partial differential equations encountered in engineering and the applied sciences is considered. A particular software package called PDE/PROTRAN that can solve a general class of either time-dependent, steady-state, or eigenvalue type PDEs in two space dimensions is examined from both a theoretical and practical perspective. To illustrate the application of PDE/PROTRAN, two example problems that have an origin in the engineering sciences are posed and translated into a working computer code. Solutions to these mathematical models, which describe diffusion-reaction phenomena and fluid dynamics, are also given and compared to previous solutions where available. Some advantages and limitations of the program and possible enhancements are also discussed.
Two-dimensional ionospheric flow pattern associated with auroral streamers

[1] We present direct two-dimensional flow observations and auroral images from the Super Dual Auroral Radar Network (SuperDARN) radar and Wideband Imaging Camera onboard Imager for Magnetopause-to-Aurora Global Exploration (IMAGE/WIC) imager to investigate the ionospheric flow pattern associated with auroral streamers for four events. Using the SuperDARN observations allows us to observe the flow associated with the streamers in the context of the larger-scale background convection. For all four cases studied, streamers developed from preexisting east-west (EW) arcs that initiated from bead-like or small-scale auroral intensifications around the auroral poleward boundary. We find a vortex-like flow pattern with clockwise sense surrounding both the initial auroral forms and the ensuing streamers. We also found in three cases signatures of flow bifurcations at the equatorward end of the streamers, which suggests a double vortex-like flow pattern with the counterclockwise vortex east of the clockwise one. Our results are consistent with the double-vortex flow structure that results from interchange convection associated with a plasma sheet bubble predicted by different numerical simulations. This supports several previous studies and offers more complete observational evidence that the observed flow pattern may be the ionospheric manifestation of interchange instability in the plasma sheet.
Stability analysis of swarms

In this note, we specify an "individual-based" continuous-time model for swarm aggregation in n-dimensional space and study its stability properties. We show that the individuals (autonomous agents or biological creatures) will form a cohesive swarm in a finite time. Moreover, we obtain an explicit bound on the swarm size, which depends only on the parameters of the swarm model.
The Capitalization of Building Codes in House Prices

Some research shows that homes built under tougher building codes perform better in hurricanes. While houses built after the implementation of the stronger building codes could be presumed to be “safer”, no study has measured the extent to which stricter building codes are capitalized into improved property. This study measures the capitalization of stricter building codes into house prices. In addition, the study examines whether homebuyers attach greater value to the stricter building codes after the “reality check” of the 2004 and 2005 hurricane seasons. A hedonic pricing model is used to capture the differential effect on house prices of the stricter 1994 South Florida Building Code for properties sold from 2000 through 2007 in Miami-Dade County. The model also measures any increase in the marginal value of the stronger building code after the 2004/2005 storm season. Models are estimated for the aggregate data and for three geographical zones based on risk exposure. Results show that the stricter building code has a positive effect on selling price. The greatest effect is seen in the coastal zone, which has the greatest risk exposure. Selling prices for homes built under the new code were about 10.4% higher than prices for comparable homes built under the older, less strict code. The premium for safety is shown to decrease as the hurricane risk exposure decreases. For geographical areas with less risk exposure, there is less capitalization of the stricter building code into house prices. The post-catastrophe (“reality check”) variables show that, following the minimal impact of the 2004 hurricanes on the Miami area, the premium that consumers are willing to pay for structural integrity disappears. However, after the 2005 hurricanes, which were more devastating to the Miami area, the building code premium returns.
Aqueous Hafnium Sulfate Chemistry: Structures of Crystalline Precipitates

Crystalline precipitates resulting from the hydrolysis and subsequent condensation of HfIV aqueous acidic solutions at 60–95 °C are examined and compared. By varying the concentrations of the acid and sulfate source, a variety of complex hafnium-oxo-hydroxo-sulfate clusters are isolated and structures accessed. Four novel compounds were discovered, while the structures of two known compounds, an 18-mer and a planar hexamer, were updated. In total, the compounds described herein each contain one of four cluster architectures: 18-mer, 11-mer, nonamer, and planar hexamer. In addition, one compound contains small amounts of 19-mers together with 18-mers. As well as examining the individual structure of each complex cluster, we relate them to one another, as well as to the dense phases of HfO2, to gain an understanding of their formation and stability. Finally, the solution conditions under which each cluster forms are identified by plotting the crystallization regions of each cluster against acidity and sulfa...